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6218b91f426218711a0fb60f49a4bcbffb49a744 | wikidoc | CLSTN1 | CLSTN1
Calsyntenin-1 is a protein that in humans is encoded by the CLSTN1 gene.
# Clinical relevance
Mutations in this gene have been shown associated to pathogenic mechanisms of Alzheimer's disease.
# Interactions
CLSTN1 has been shown to interact with APBA2 and Amyloid precursor protein. | CLSTN1
Calsyntenin-1 is a protein that in humans is encoded by the CLSTN1 gene.[1][2]
# Clinical relevance
Mutations in this gene have been shown associated to pathogenic mechanisms of Alzheimer's disease.[3]
# Interactions
CLSTN1 has been shown to interact with APBA2[4][5] and Amyloid precursor protein.[4][5] | https://www.wikidoc.org/index.php/CLSTN1 | |
7310a5890368fcb03a0ffc3b76325a658a31e3ba | wikidoc | CLUAP1 | CLUAP1
Clusterin associated protein 1, also known as CLUAP1, is a human gene.
# Model organisms
Model organisms have been used in the study of CLUAP1 function. A conditional knockout mouse line, called Cluap1tm1a(KOMP)Wtsi was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Twenty six tests were carried out on mutant mice and four significant abnormalities were observed. No homozygous mutant embryos were identified during gestation, and therefore none survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice; both sexes had decreased IgG1 levels while males also displayed abnormal spine curvature resulting in kyphosis. | CLUAP1
Clusterin associated protein 1, also known as CLUAP1, is a human gene.[1]
# Model organisms
Model organisms have been used in the study of CLUAP1 function. A conditional knockout mouse line, called Cluap1tm1a(KOMP)Wtsi[7][8] was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.[9][10][11]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[5][12] Twenty six tests were carried out on mutant mice and four significant abnormalities were observed.[5] No homozygous mutant embryos were identified during gestation, and therefore none survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice; both sexes had decreased IgG1 levels while males also displayed abnormal spine curvature resulting in kyphosis.[5] | https://www.wikidoc.org/index.php/CLUAP1 | |
48293476ea6e38b08025387fe386252af4adb2a9 | wikidoc | CMKLR1 | CMKLR1
Chemokine like receptor 1 also known as ChemR23 (Chemerin Receptor 23) is a protein that in humans is encoded by the CMKLR1 gene. Chemokine receptor-like 1 is a G protein-coupled receptor for the chemoattractant adipokine chemerin and the omega-3 fatty acid eicosapentaenoic acid-derived specialized pro-resolving molecule, resolvin E1 (see Specialized proresolving mediators#EPA-derived resolvins (i.e. RvE)). The murine receptor that shares almost 80% homology with the human receptor, is called Dez.
# Tissue distribution
CMKLR1 shows wide RNA expression profile but is notably high in plasmacytoid dendritic cells, macrophages, cardiomyocytes, adipocytes and endothelial cells.
# Function
Activating CMKLR1 by an agonist mobilizes intracellular calcium and causes the activation of several other signaling cascades like the ERK1 and NF-κB. Initial studies of CMKLR1 suggested that it might have a role in the inflammatory pathways. Its cognate ligand, chemerin was found in joint aspirate from rheumatoid arthritis and absent in aspirate from degenerative arthritis. CMKLR1 expression by plasmacytoid dendritic cells and macrophages also helped foster this idea. In vitro chemotaxis assays showed it to be utilized in attracting these cells. As an adipokine receptor it has a role in adipogenesis and adipocyte maturation. It seems also to have a role in peripheral insulin resistance.
Also studies using the mouse zymosan model and chemerin peptides showed that these peptides suppressed and helped resolve the peritonitis in mice. The same model showed that this particular molecule enhances macrophage efferocytosis (phagocyting apoptotic cells).
# Receptor antagonist CCX832
CCX832 is an orally active molecule used as a tool compound in experimental pharmacology. It antagonises the effect of CMKLR1. It is listed on the Guide to Pharmacology database as the only example of a CMKLR1 antagonist. Its chemical structure is undisclosed.
The substance was originally developed for use as a pharmaceutical drug against inflammatory diseases by ChemoCentryx, a pharmaceutical firm based in California, in alliance with GlaxoSmithKline (GSK). Development was terminated after a Phase I clinical trial in 2012. | CMKLR1
Chemokine like receptor 1 also known as ChemR23 (Chemerin Receptor 23) is a protein that in humans is encoded by the CMKLR1 gene.[1][2] Chemokine receptor-like 1 is a G protein-coupled receptor for the chemoattractant adipokine chemerin[3] and the omega-3 fatty acid eicosapentaenoic acid-derived specialized pro-resolving molecule, resolvin E1 (see Specialized proresolving mediators#EPA-derived resolvins (i.e. RvE)).[4] The murine receptor that shares almost 80% homology with the human receptor, is called Dez.[5]
# Tissue distribution
CMKLR1 shows wide RNA expression profile but is notably high in plasmacytoid dendritic cells, macrophages, cardiomyocytes, adipocytes and endothelial cells.[6]
# Function
Activating CMKLR1 by an agonist mobilizes intracellular calcium and causes the activation of several other signaling cascades like the ERK1 and NF-κB. Initial studies of CMKLR1 suggested that it might have a role in the inflammatory pathways. Its cognate ligand, chemerin was found in joint aspirate from rheumatoid arthritis and absent in aspirate from degenerative arthritis. CMKLR1 expression by plasmacytoid dendritic cells and macrophages also helped foster this idea. In vitro chemotaxis assays showed it to be utilized in attracting these cells. As an adipokine receptor it has a role in adipogenesis and adipocyte maturation.[7] It seems also to have a role in peripheral insulin resistance.[8]
Also studies using the mouse zymosan model and chemerin peptides showed that these peptides suppressed and helped resolve the peritonitis in mice.[9] The same model showed that this particular molecule enhances macrophage efferocytosis (phagocyting apoptotic cells).[10]
# Receptor antagonist CCX832
CCX832 is an orally active molecule used as a tool compound in experimental pharmacology. It antagonises the effect of CMKLR1.[11][12][13] It is listed on the Guide to Pharmacology database as the only example of a CMKLR1 antagonist. Its chemical structure is undisclosed.[14]
The substance was originally developed for use as a pharmaceutical drug against inflammatory diseases by ChemoCentryx, a pharmaceutical firm based in California, in alliance with GlaxoSmithKline (GSK).[15] Development was terminated after a Phase I clinical trial in 2012.[16] | https://www.wikidoc.org/index.php/CMKLR1 | |
4eeb95d53f648512393ce4ba5eb5681e1e349431 | wikidoc | CNKSR2 | CNKSR2
Connector enhancer of kinase suppressor of ras 2, also known as CNK homolog protein 2 (CNK2) or maguin (membrane-associated guanylate kinase-interacting protein), is an enzyme that in humans is encoded by the CNKSR2 gene.
# Function
CNKSR2 is a multidomain protein that functions as a scaffold protein to mediate the mitogen-activated protein kinase pathways downstream from Ras. This gene product is induced by vitamin D and inhibits apoptosis in certain cancer cells. It may also play a role in ternary complex assembly of synaptic proteins at the postsynaptic membrane and coupling of signal transduction to membrane/cytoskeletal remodeling.
# Mechanism of action
It is the mammalian homolog of the Drosophilia gene Cnk, which is known to bind Raf, and is implicated in ras signalling. It has been show that CNKSR2 is also a Raf binding protein, and is assumed to function in bringing together the Ras signalling complex at the post synaptic density.
It is known to have two isoforms, one of which binds PSD95 and S-SCAM (synaptic scaffolding molecule) through its PDZ domain, and another which does not. Both of the isoforms are, however, known to be synaptically localized, and it is understood that this is mediated by the Pleckstrin homology domain. It's synaptic localization is not known to be affected by NMDA receptor activation. Overexpression of Maguin's C-terminal PDZ domain is known to repress synaptic localization of PSD95. In cultures, MAGUIN colocalizes with PSD95 and synaptophysin at puncta in neurites, and these puncta are first visible at 6DIV.
Proteomic work done on binding partners of Ksr2 suggests that the CNKSR2/KSR2 complex may play a role in mediating crosstalk between the MAPK, Pi3K and insulin pathways. It was found to form a complex with MEK1 (Erk2, p38), MEK2, cdk4, PI3k, the phosphatases PP2A and PP^, and also various translational, ribosomal, transport and structural proteins. It remains to be established how many of these are affected by CNKSR2, and whether this remains true for Ksr2 in the nervous system.
Densin-180 is another important synaptic protein found to interact with CNKSR2. It is known to bind at its C-terminal PDZ domain. In transfected cells, no association could be found between PSD95 and Densin-180 without the presence of CNKSR2. This brings it into a complex with CamKII and β-catenin, and further to the binding partners of CNKSR2 suggest that CNKSR2 may have a role in dendritic branching. | CNKSR2
Connector enhancer of kinase suppressor of ras 2, also known as CNK homolog protein 2 (CNK2) or maguin (membrane-associated guanylate kinase-interacting protein), is an enzyme that in humans is encoded by the CNKSR2 gene.[1]
# Function
CNKSR2 is a multidomain protein that functions as a scaffold protein to mediate the mitogen-activated protein kinase pathways downstream from Ras. This gene product is induced by vitamin D and inhibits apoptosis in certain cancer cells. It may also play a role in ternary complex assembly of synaptic proteins at the postsynaptic membrane and coupling of signal transduction to membrane/cytoskeletal remodeling.[1]
# Mechanism of action
It is the mammalian homolog of the Drosophilia gene Cnk, which is known to bind Raf, and is implicated in ras signalling. It has been show that CNKSR2 is also a Raf binding protein, and is assumed to function in bringing together the Ras signalling complex at the post synaptic density.[2]
It is known to have two isoforms, one of which binds PSD95 and S-SCAM (synaptic scaffolding molecule) through its PDZ domain, and another which does not. Both of the isoforms are, however, known to be synaptically localized, and it is understood that this is mediated by the Pleckstrin homology domain. It's synaptic localization is not known to be affected by NMDA receptor activation. Overexpression of Maguin's C-terminal PDZ domain is known to repress synaptic localization of PSD95. In cultures, MAGUIN colocalizes with PSD95 and synaptophysin at puncta in neurites, and these puncta are first visible at 6DIV.
Proteomic work done on binding partners of Ksr2 suggests that the CNKSR2/KSR2 complex may play a role in mediating crosstalk between the MAPK, Pi3K and insulin pathways.[3] It was found to form a complex with MEK1 (Erk2, p38), MEK2, cdk4, PI3k, the phosphatases PP2A and PP^, and also various translational, ribosomal, transport and structural proteins. It remains to be established how many of these are affected by CNKSR2, and whether this remains true for Ksr2 in the nervous system.
Densin-180 is another important synaptic protein found to interact with CNKSR2. It is known to bind at its C-terminal PDZ domain. In transfected cells, no association could be found between PSD95 and Densin-180 without the presence of CNKSR2.[4] This brings it into a complex with CamKII and β-catenin, and further to the binding partners of CNKSR2 suggest that CNKSR2 may have a role in dendritic branching. | https://www.wikidoc.org/index.php/CNKSR2 | |
e55757ab73d8d4da27925a1808370e231334f7db | wikidoc | VPS13B | VPS13B
VPS13B also known as vacuolar protein sorting-associated protein 13B is a protein that in humans is encoded by the VPS13B gene. It is a giant protein associated with the Golgi apparatus that is believed to be involved in post Golgi apparatus sorting and trafficking. Mutations in the human VPS13B gene cause Cohen syndrome.
VPS13B gene is also referred to as CHS1, COH1, KIAA0532, and DKFZp313I0811.
Cytogenetic location of the human VPS13B gene is 8q22, which is the long arm of chromosome eight at position 22.2. There has been various splice variants encoding isoforms identified. The canonical form of the expressed protein encoded by the human VPS13B gene has 3997 amino acids.
# Gene
The VPS13B gene is located on chromosome 8q22, and which deletions in this chromosome are associated with Cohen Syndrome, which is why this gene is alternatively called COH1. The gene is made up of 66 exons, 4 of which are alternative. The pattern of alternative splicing in the VS13B gene is complex in the analyzed regions including exons 28B and 28. This eventually causes 4 termination codons and 3 alternatively spliced forms to be in use. Exon 2 is where its translation start codon occurs. VPS13B is a large gene; It spans a genomic DNA sequence region of about 864 kilobase pairs, or 846,000 base pairs. The VPS13B gene is widely expressed, especially in prostate, testis, ovary, and colon with transcripts of about 12 to 14 kilobase pairs. It is also expressed in fetal brain, liver, and kidney, with transcripts of about 2.0 to 5.0 kilobase pairs. Expression in the adult brain is very minimal. Variants 1A and 2A are the principle variants of the gene that encodes a 4,022 and 39,997 amino acid protein, respectively. 2 Alu repeat sequences are present in the three prime untranslated region.
# Nomenclature
The VPS13B gene is also known as:
- CHS1
- COH1
- Cohen syndrome 1
- DKFZp313I0811
- KIAA0532
- vacuolar protein sorting 13 homolog B (yeast)
- vacuolar protein sorting 13B
- VP13B_HUMAN
# Function
Proteins produced from the VPS13B gene area part of the Golgi apparatus. They are also responsible for sorting and transporting of proteins inside of the cell. The VPS13B protein is important because it plays an important role in the function of normal growth, the development of neurons, and the development of adipocytes. This protein may also play a role in the development of the function for eyes, the hematological system, the central nervous system, and in the storage and distribution of fats in the body. The VPS13B is found at locus 8q22.2. This means that the VPS13B gene is located on chromosome 8 at position 22.2 on the long q arm at 8q22.2. The VPS13B protein is composed of 4,022 amino acids and might have a total of ten trans-membrane domains and a complex pattern of functional motifs.
Presently, the VPS13B gene is recognized as a protein-coding gene that produces the VPS13B protein. The VPS13B protein has been associated with the Golgi apparatus and intracellular processes such as protein modification, protein organization, and protein distribution. It has also been speculated that the VPS13B protein may influence the development of certain somatic cells and body systems, and may be involved in the storing and allocation of fats in humans.
Mutations in the VPS13B gene can result in the abnormal function of the VPS13B protein. Mutations within the gene have been linked as a potential factor in Cohen Syndrome and autism. In Cohen syndrome, it is thought that deletion mutations in the gene alter the shape of the VPS13B protein, resulting in a shorter, nonfunctioning protein. Altered VPS13B protein is then unable to function properly due to these genetic changes, thus resulting in an obstruction of regular processes. Studies have also linked mutations in the VPS13B gene to osteoporosis. An association between an increase of the VPS13B copy number variants and a lower bone mineral density in adults has been found. Still, the normal, definitive function of the VPS13B gene is unknown, as are the specific implications of its mutated forms.
# Clinical significance
Over 150 types of different mutations in the VPS13B gene have been identified in individuals diagnosed with Cohen syndrome. A deletion in the VPS13B gene causes a premature stop signal in the instructions for making the VPS13B protein, causing the protein to become abnormally short and nonfunctional. When this happens, the nonfunctional protein causes the Golgi apparatus not to work properly and stops normal glycosylation.
## Cohen syndrome
COH1 depletion in HeLa cells by RNA interference disrupts normal Golgi organization. Deletions in this gene is a cause of autosomal recessive Cohen syndrome. Fibroblasts from Cohen syndrome patients also have abnormal Golgi. Cohen syndrome patients have been shown to have defective protein glycosylation, which is a major function of the Golgi, thus supporting the suggestion that Golgi dysfunction contributes to Cohen syndrome pathology.
Cohen syndrome is a very rare inherited genetic condition, that has been diagnosed in almost one thousand people worldwide. It occurs when there is a mutation in one’s VPS13B gene. This disorder causes a variety of symptoms that never ease. Microcephaly, hypotonia, worsening eyesight, retinal dystrophy, delayed puberty, hyper mobility, and obesity are just a few examples. People with this syndrome have distinct facial features that differ from the normal view of one. They have bulging noses, unusually shaped eyes, very thick hair, narrow hands and feet, almond like eyes, and very long, thin fingers.
The symptoms of Cohen syndrome begin to show at a very young age. At birth, newborns can show no symptoms at all, but once they start to develop their facial characteristics, it will be noticeable. It then begins with failure to thrive in infants and children, from there it is when all of the developmental delays start to show: microcephaly, retinochorodial dystrophy, psychomotor retardation, high myopia, neutropenia, joint hyper mobility and the distinct facial features start forming. Then, during the teenage and adolescent years, short stature and obesity start to become concerns. Almost thirty percent of people with this syndrome are non verbal and illiterate. In many instances where speech delay is prominent in this syndrome, aphthous ulcers are all inside the mouth causing a lot of pain to the affected individual. Over time, many Cohen syndrome affected people start to lose their eyesight by the mere age of thirty. Although Cohen syndrome does not decrease one’s life expectancy, but it reduces their quality of life due to being unable to speak and/or see. Patients with this syndrome are known to also suffer from seizures, narrow hands and feet, and growth hormone deficiencies.
Cohen syndrome is an autosomal recessive disorder that is characterized by mainly facial dysmorphism, microcephaly, joint laxity and intermittent neutropenia. Cohen syndrome is inherited in an autosomal recessive manner, which means there is a 50 percent chance of being a carrier. Children of people with this syndrome are carriers for the syndrome. Seventy-five percent of individuals with Cohen syndrome, in the Finnish population, have a mutation in both copies of the gene. Mutations in the gene VPS13B only occur in a small number of families, outside of Finnish and Amish groups.
## Neutropenia
Another disease that the VPS13B gene contributes to is neutropenia. The disease is that the person will have a low concentration of neutrophils. Neutrophils is a type of white blood cell. Which it causes the person to be able to catch other infections and disease easier. Even though it is a genetic disease it can be cause by certain medications and sometimes your bone marrow.
## Sutton disease 2
Sutton disease is a chronic inflammatory disease that happens in a person mouth. It creates painful ulcers in the mouth area. The sours can be different size and different pain levels. Another name for this disease that it is commonly known for is canker sores.
## Ewing sarcoma
Ewing sarcoma is a cancers tumor that happens in your bones or soft tissues. Examples for this cartilage or nerves. It usually shows up in children, teens and young adults. There are other diseases that are similar to the Ewing sarcoma but this one is the only one that has the VPS13B gene.
## Microcephaly
Microcephaly is a medical condition which the head is misshaped and is smaller than the normal size head shape. The reason it occurs is that will the fetus was in the womb its head stopped forming or the brain stop forming. It effects the head and brain shaped. Even when this occurs the person will be normal, and it does not affect them, but this is on occasion. Most of the time when this happens, they have problems with seizures, development delays, problems with movement and also balance, hard time eating, and hearing loss and losing vision can occur.
## Other
Syndromic autism is also associated with this gene, as well as intellectual disability. | VPS13B
VPS13B also known as vacuolar protein sorting-associated protein 13B is a protein that in humans is encoded by the VPS13B gene. It is a giant protein associated with the Golgi apparatus that is believed to be involved in post Golgi apparatus sorting and trafficking.[1] Mutations in the human VPS13B gene cause Cohen syndrome.
VPS13B gene is also referred to as CHS1, COH1, KIAA0532,[2] and DKFZp313I0811.[3]
Cytogenetic location of the human VPS13B gene is 8q22, which is the long arm of chromosome eight at position 22.2. There has been various splice variants encoding isoforms identified. The canonical form of the expressed protein encoded by the human VPS13B gene has 3997 amino acids.[2]
# Gene
The VPS13B gene is located on chromosome 8q22, and which deletions in this chromosome are associated with Cohen Syndrome, which is why this gene is alternatively called COH1.[4] The gene is made up of 66 exons, 4 of which are alternative.[5] The pattern of alternative splicing in the VS13B gene is complex in the analyzed regions including exons 28B and 28. This eventually causes 4 termination codons and 3 alternatively spliced forms to be in use.[6] Exon 2 is where its translation start codon occurs.[5] VPS13B is a large gene; It spans a genomic DNA sequence region of about 864 kilobase pairs, or 846,000 base pairs.[5] The VPS13B gene is widely expressed, especially in prostate, testis, ovary, and colon with transcripts of about 12 to 14 kilobase pairs. It is also expressed in fetal brain, liver, and kidney, with transcripts of about 2.0 to 5.0 kilobase pairs. Expression in the adult brain is very minimal.[7] Variants 1A and 2A are the principle variants of the gene that encodes a 4,022 and 39,997 amino acid protein, respectively.[4] 2 Alu repeat sequences are present in the three prime untranslated region.[8]
# Nomenclature
The VPS13B gene is also known as:[9]
- CHS1[9]
- COH1[9]
- Cohen syndrome 1[9]
- DKFZp313I0811[9]
- KIAA0532[9]
- vacuolar protein sorting 13 homolog B (yeast)[9]
- vacuolar protein sorting 13B[9]
- VP13B_HUMAN[9]
# Function
Proteins produced from the VPS13B gene area part of the Golgi apparatus.[9] They are also responsible for sorting and transporting of proteins inside of the cell.[9] The VPS13B protein is important because it plays an important role in the function of normal growth, the development of neurons, and the development of adipocytes.[9] This protein may also play a role in the development of the function for eyes, the hematological system, the central nervous system, and in the storage and distribution of fats in the body.[10] The VPS13B is found at locus 8q22.2.[9] This means that the VPS13B gene is located on chromosome 8 at position 22.2 on the long q arm at 8q22.2.[9] The VPS13B protein is composed of 4,022 amino acids and might have a total of ten trans-membrane domains and a complex pattern of functional motifs.[11]
Presently, the VPS13B gene is recognized as a protein-coding gene that produces the VPS13B protein.[12] The VPS13B protein has been associated with the Golgi apparatus and intracellular processes such as protein modification, protein organization, and protein distribution.[13] It has also been speculated that the VPS13B protein may influence the development of certain somatic cells and body systems, and may be involved in the storing and allocation of fats in humans.[2][13]
Mutations in the VPS13B gene can result in the abnormal function of the VPS13B protein. Mutations within the gene have been linked as a potential factor in Cohen Syndrome and autism.[13][14][15][16] In Cohen syndrome, it is thought that deletion mutations in the gene alter the shape of the VPS13B protein, resulting in a shorter, nonfunctioning protein.[13][15] Altered VPS13B protein is then unable to function properly due to these genetic changes, thus resulting in an obstruction of regular processes.[13] Studies have also linked mutations in the VPS13B gene to osteoporosis.[4] An association between an increase of the VPS13B copy number variants and a lower bone mineral density in adults has been found.[4] Still, the normal, definitive function of the VPS13B gene is unknown, as are the specific implications of its mutated forms.
# Clinical significance
Over 150 types of different mutations in the VPS13B gene have been identified in individuals diagnosed with Cohen syndrome.[9] A deletion in the VPS13B gene causes a premature stop signal in the instructions for making the VPS13B protein, causing the protein to become abnormally short and nonfunctional.[9] When this happens, the nonfunctional protein causes the Golgi apparatus not to work properly and stops normal glycosylation.[9]
## Cohen syndrome
COH1 depletion in HeLa cells by RNA interference disrupts normal Golgi organization. Deletions in this gene is a cause of autosomal recessive Cohen syndrome. Fibroblasts from Cohen syndrome patients also have abnormal Golgi.[17] Cohen syndrome patients have been shown to have defective protein glycosylation,[18] which is a major function of the Golgi, thus supporting the suggestion that Golgi dysfunction contributes to Cohen syndrome pathology.[17]
Cohen syndrome is a very rare inherited genetic condition, that has been diagnosed in almost one thousand people worldwide. It occurs when there is a mutation in one’s VPS13B gene. This disorder causes a variety of symptoms that never ease. Microcephaly, hypotonia, worsening eyesight, retinal dystrophy, delayed puberty, hyper mobility, and obesity are just a few examples. People with this syndrome have distinct facial features that differ from the normal view of one. They have bulging noses, unusually shaped eyes, very thick hair, narrow hands and feet, almond like eyes, and very long, thin fingers.[19]
The symptoms of Cohen syndrome begin to show at a very young age. At birth, newborns can show no symptoms at all, but once they start to develop their facial characteristics, it will be noticeable.[20] It then begins with failure to thrive in infants and children, from there it is when all of the developmental delays start to show: microcephaly, retinochorodial dystrophy, psychomotor retardation, high myopia, neutropenia, joint hyper mobility and the distinct facial features start forming. Then, during the teenage and adolescent years, short stature and obesity start to become concerns. Almost thirty percent of people with this syndrome are non verbal and illiterate.[21] In many instances where speech delay is prominent in this syndrome, aphthous ulcers are all inside the mouth causing a lot of pain to the affected individual. Over time, many Cohen syndrome affected people start to lose their eyesight by the mere age of thirty. Although Cohen syndrome does not decrease one’s life expectancy, but it reduces their quality of life due to being unable to speak and/or see.[20] Patients with this syndrome are known to also suffer from seizures, narrow hands and feet, and growth hormone deficiencies.[22]
Cohen syndrome is an autosomal recessive disorder that is characterized by mainly facial dysmorphism, microcephaly, joint laxity and intermittent neutropenia. Cohen syndrome is inherited in an autosomal recessive manner, which means there is a 50 percent chance of being a carrier. Children of people with this syndrome are carriers for the syndrome.[15] Seventy-five percent of individuals with Cohen syndrome, in the Finnish population, have a mutation in both copies of the gene. Mutations in the gene VPS13B only occur in a small number of families, outside of Finnish and Amish groups.[13]
## Neutropenia
Another disease that the VPS13B gene contributes to is neutropenia. The disease is that the person will have a low concentration of neutrophils.[23] Neutrophils is a type of white blood cell. Which it causes the person to be able to catch other infections and disease easier.[23] Even though it is a genetic disease it can be cause by certain medications and sometimes your bone marrow.[23]
## Sutton disease 2
Sutton disease is a chronic inflammatory disease that happens in a person mouth. It creates painful ulcers in the mouth area.[24] The sours can be different size and different pain levels. Another name for this disease that it is commonly known for is canker sores.[24]
## Ewing sarcoma
Ewing sarcoma is a cancers tumor that happens in your bones or soft tissues.[25] Examples for this cartilage or nerves.[25] It usually shows up in children, teens and young adults.[25] There are other diseases that are similar to the Ewing sarcoma but this one is the only one that has the VPS13B gene.[25]
## Microcephaly
Microcephaly is a medical condition which the head is misshaped and is smaller than the normal size head shape.[26] The reason it occurs is that will the fetus was in the womb its head stopped forming or the brain stop forming.[26] It effects the head and brain shaped. Even when this occurs the person will be normal, and it does not affect them, but this is on occasion.[26] Most of the time when this happens, they have problems with seizures, development delays, problems with movement and also balance, hard time eating, and hearing loss and losing vision can occur.[26]
## Other
Syndromic autism is also associated with this gene,[3] as well as intellectual disability.[27][28] | https://www.wikidoc.org/index.php/COH1 | |
3a01f5a839039284d1f3285ad9b19fbb864cb903 | wikidoc | COL3A1 | COL3A1
Collagen, type III, alpha 1 (Ehlers-Danlos syndrome type IV, autosomal dominant), also known as COL3A1, is a human gene.
This gene encodes a fibrillar collagen that is found in extensible connective tissues such as skin, lung, and the vascular system, frequently in association with type I collagen. Mutations in this gene are associated with Ehlers-Danlos syndrome type IV, and with aortic and arterial aneurysms. Although alternate transcripts have been detected for this gene, they are the result of mutations; these mutations alter splicing, often leading to the exclusion of multiple exons.
Type-III collagen is a fibrous scleroprotein in bone, cartilage, tendon, bone marrow stroma and other connective tissue; yields gelatin on boiling.
Scleroprotein is a simple protein found in horny and cartilaginous tissues and in the lens of the eye. | COL3A1
Collagen, type III, alpha 1 (Ehlers-Danlos syndrome type IV, autosomal dominant), also known as COL3A1, is a human gene.
This gene encodes a fibrillar collagen that is found in extensible connective tissues such as skin, lung, and the vascular system, frequently in association with type I collagen. Mutations in this gene are associated with Ehlers-Danlos syndrome type IV, and with aortic and arterial aneurysms. Although alternate transcripts have been detected for this gene, they are the result of mutations; these mutations alter splicing, often leading to the exclusion of multiple exons.[1]
Type-III collagen is a fibrous scleroprotein in bone, cartilage, tendon, bone marrow stroma [2] and other connective tissue; yields gelatin on boiling.
Scleroprotein is a simple protein found in horny and cartilaginous tissues and in the lens of the eye. | https://www.wikidoc.org/index.php/COL3A1 | |
04763f80536f94af1fff31440484d80c0278771f | wikidoc | COL4A1 | COL4A1
Collagen, type IV, alpha 1, also known as COL4A1, is a human gene.
This gene encodes the major type IV alpha collagen chain of basement membranes. Like the other members of the type IV collagen gene family, this gene is organized in a head-to-head conformation with another type IV collagen gene so that each gene pair shares a common promoter.
Mutations in COL4A1 exons 24 and 25 are associated with HANAC (autosomal dominant hereditary angiopathy with nephropathy, aneurysms, and muscle cramps). | COL4A1
Collagen, type IV, alpha 1, also known as COL4A1, is a human gene.[1]
This gene encodes the major type IV alpha collagen chain of basement membranes. Like the other members of the type IV collagen gene family, this gene is organized in a head-to-head conformation with another type IV collagen gene so that each gene pair shares a common promoter.[2]
Mutations in COL4A1 exons 24 and 25 are associated with HANAC (autosomal dominant hereditary angiopathy with nephropathy, aneurysms, and muscle cramps).[3] | https://www.wikidoc.org/index.php/COL4A1 | |
6062d3ec36934013cda983c0a43dd7f9f888a2a8 | wikidoc | CORO1A | CORO1A
Coronin-1A is a protein that in humans is encoded by the CORO1A gene. It has been implicated in both T-cell mediated immunity and mitochondrial apoptosis. In a recent genome-wide longevity study, its expression levels were found to be negatively associated both with age at the time of blood sample and the survival time after blood draw.
# Discovery
The Coronin protein family was discovered in 1991 by Eugenio L. Hostos. Hostos used a cytoskeletal preparation called the “contracted propeller” that efficiently helped with the purification of cytoskeletal proteins. This technique allowed him to precipitate actomyosin components together with the desired proteins.
These protein were named Corona, which is the Latin word for crown, because of the crown-like shape that it forms when making contact with the surface of the cell. Coronin-1a has been the most researched one due to its complexity and
intriguing structural components. After research, it was determined that Coronin-1a serves as actin binding facilitator when reacted with K-glutamate. The anion K + and glutamate were used because of it similarity to the environment inside the cell, allowing Coronin-1a to bind to F-actin.
Later on, the complementary DNA (cDNA) of Coronin-1a was cloned in an expression library, this led to the conclusion that Coronin-1a has very similar structure to the beta (β) subunits of the G proteins (Gβ). Therefore, it was established that Coronin-1a has five WD motif repeats, and this repeats seven times forming a propeller like structure.
In the cell, Coronin-1a serves as an auxiliary to many cytoskeletal process that involve actin. It was concluded that Coronin-1a is known to affect the “cytoskeletal reorganization” as well “actin dynamics” together with other protein.
## Phylogeny
The Coronin family is composed of twelve subfamilies which include: seven subfamilies that fall under vertebrates and five subfamilies that are composed of meteozas, fungi and amoeba.
The evolutionary Coronin family subfamilies have been grouped by its similarities and relationships between the different proteins. As we can see Coronin-1a (also referenced as CORO1A, Coronin 4 and CRN4) has been found in 19 vertebrates.
# Function
The Coronin family is composed of twelve subfamilies which include: seven subfamilies that fall under vertebrates and five subfamilies that are composed of meteozas, fungi and amoeba.
Coronin-1a has been found in the cell cortex of macrophages, which are white blood cells, helping with a process called phagocytosis.The model on Figure 3 shows Coronin-1a’s involvement in macrophages. When the cell is at rest,Coronin-1a is spread out throughout the cytoplasm and the cell cortex. Therefore, when a pathogen enters the cell, Coronin-1a binds to phagosomal membrane making sure of the binding and activation of calcinuerin, this resulting in a stop of fusion lysosomes with phagosomes. In other words, if Coronin-1a is removed and calcinuerin is inhibited then it allows the initiation of the fusion of phagosomes with lysosome and the killing of mycobacteria.
The phylogenetic tree of the Coronin family it is quiet broad. The same way that Coronin-1a helps with the reorganization of the cytoskeleton and dynamic activity with other proteins in vertebrates, Coronin can also be seen in non-vertebrates for example the Toxoplasma gondii Coronin (also known as TgCor).
Toxoplasma gondii Coronin (TgCor) binds to F-actin and it accelerates the actin polymerization process. It also prevents incursions and exits. As well as every other coronin, TgCor is an actin binding protein, it delocalizes to the posterior side of invading parasites and blocks them from leaving.
# Structure
The structure of Coronin-1A is made out of five WD repeats, and this motifs repeat seven time forming a propeller like structures.
The new ribbon visualization of the secondary structure of Coronin-1a. In model A, is the front view of Coronin-1a, the secondary structure allows you to clearly see the parallel beta sheets moving towards the bottom of the
structure. Model B, is the side view of the protein which shows the turns and the coils between the beta sheets. From this pictures we are able to see that the alpha helix and helix strands are concentrated at the bottom of the protein.
Coronin-1a was input into Database of Secondary Structure Program (DSSP), where the PDB database entered and a secondary structure panel is designed where one is clearly able to see the seven repeat that makes the propeller. Also, it
displays the amino acid sequence of Coronin-1a. The yellow arrows mean the beta strands, the purple loops are the turns, the black lines means empty meaning that there was no secondary structure assigned, the light pink is 3/10-helix is formed, royal blue line is a bend and finally the red helix signifies the alpha helices. | CORO1A
Coronin-1A is a protein that in humans is encoded by the CORO1A gene.[1][2] It has been implicated in both T-cell mediated immunity and mitochondrial apoptosis. In a recent genome-wide longevity study, its expression levels were found to be negatively associated both with age at the time of blood sample and the survival time after blood draw.[3]
# Discovery
The Coronin protein family was discovered in 1991 by Eugenio L. Hostos. Hostos used a cytoskeletal preparation called the “contracted propeller” that efficiently helped with the purification of cytoskeletal proteins. This technique allowed him to precipitate actomyosin components together with the desired proteins.[4]
These protein were named Corona, which is the Latin word for crown, because of the crown-like shape that it forms when making contact with the surface of the cell. Coronin-1a has been the most researched one due to its complexity and
intriguing structural components. After research, it was determined that Coronin-1a serves as actin binding facilitator when reacted with K-glutamate. The anion K + and glutamate were used because of it similarity to the environment inside the cell, allowing Coronin-1a to bind to F-actin.
Later on, the complementary DNA (cDNA) of Coronin-1a was cloned in an expression library, this led to the conclusion that Coronin-1a has very similar structure to the beta (β) subunits of the G proteins (Gβ). Therefore, it was established that Coronin-1a has five WD motif repeats, and this repeats seven times forming a propeller like structure.[4]
In the cell, Coronin-1a serves as an auxiliary to many cytoskeletal process that involve actin. It was concluded that Coronin-1a is known to affect the “cytoskeletal reorganization” as well “actin dynamics” together with other protein.
[4]
## Phylogeny
The Coronin family is composed of twelve subfamilies which include: seven subfamilies that fall under vertebrates and five subfamilies that are composed of meteozas, fungi and amoeba.
The evolutionary Coronin family subfamilies have been grouped by its similarities and relationships between the different proteins. As we can see Coronin-1a (also referenced as CORO1A, Coronin 4 and CRN4) has been found in 19 vertebrates.[5]
# Function
The Coronin family is composed of twelve subfamilies which include: seven subfamilies that fall under vertebrates and five subfamilies that are composed of meteozas, fungi and amoeba.
Coronin-1a has been found in the cell cortex of macrophages, which are white blood cells, helping with a process called phagocytosis.The model on Figure 3 shows Coronin-1a’s involvement in macrophages. When the cell is at rest,Coronin-1a is spread out throughout the cytoplasm and the cell cortex. Therefore, when a pathogen enters the cell, Coronin-1a binds to phagosomal membrane making sure of the binding and activation of calcinuerin, this resulting in a stop of fusion lysosomes with phagosomes. In other words, if Coronin-1a is removed and calcinuerin is inhibited then it allows the initiation of the fusion of phagosomes with lysosome and the killing of mycobacteria.[6]
The phylogenetic tree of the Coronin family it is quiet broad. The same way that Coronin-1a helps with the reorganization of the cytoskeleton and dynamic activity with other proteins in vertebrates, Coronin can also be seen in non-vertebrates for example the Toxoplasma gondii Coronin (also known as TgCor).[7]
Toxoplasma gondii Coronin (TgCor) binds to F-actin and it accelerates the actin polymerization process. It also prevents incursions and exits. As well as every other coronin, TgCor is an actin binding protein, it delocalizes to the posterior side of invading parasites and blocks them from leaving.[7]
# Structure
The structure of Coronin-1A is made out of five WD repeats, and this motifs repeat seven time forming a propeller like structures.
The new ribbon visualization of the secondary structure of Coronin-1a. In model A, is the front view of Coronin-1a, the secondary structure allows you to clearly see the parallel beta sheets moving towards the bottom of the
structure. Model B, is the side view of the protein which shows the turns and the coils between the beta sheets. From this pictures we are able to see that the alpha helix and helix strands are concentrated at the bottom of the protein.[8]
Coronin-1a was input into Database of Secondary Structure Program (DSSP), where the PDB database entered and a secondary structure panel is designed where one is clearly able to see the seven repeat that makes the propeller. Also, it
displays the amino acid sequence of Coronin-1a. The yellow arrows mean the beta strands, the purple loops are the turns, the black lines means empty meaning that there was no secondary structure assigned, the light pink is 3/10-helix is formed, royal blue line is a bend and finally the red helix signifies the alpha helices. | https://www.wikidoc.org/index.php/CORO1A | |
80839b1fc9e3ad3fbecf098e35d2c699a401f471 | wikidoc | CORO1B | CORO1B
Coronin, actin binding protein, 1B also known as CORO1B is a protein which in humans is encoded by the CORO1B gene. Members of the coronin family, such as CORO1B, are WD repeat-containing actin-binding proteins that regulate cell motility.
# Function
A mammalian coronin enriches at the leading edge of migrating cells. Studies related to this protein are as follows:
- Coronin 1B antagonizes cortactin and remodels Arp2/3-containing actin branches in lamellipodia.
- F-actin binding is essential for coronin 1B function in vivo.
- Coronin 1B coordinates Arp2/3 complex and cofilin activities at the leading edge.
- Phosphorylation of coronin 1B by protein kinase C regulates interaction with Arp2/3 and cell motility.
- In vivo and in vitro characterization of novel neuronal plasticity factors identified following spinal cord injury.
- Isolation, cloning, and characterization of a new mammalian coronin family member, coroninse, which is regulated within the protein kinase C signaling pathway. | CORO1B
Coronin, actin binding protein, 1B also known as CORO1B is a protein which in humans is encoded by the CORO1B gene.[1] Members of the coronin family, such as CORO1B, are WD repeat-containing actin-binding proteins that regulate cell motility.[2]
# Function
A mammalian coronin enriches at the leading edge of migrating cells.[3] Studies related to this protein are as follows:
- Coronin 1B antagonizes cortactin and remodels Arp2/3-containing actin branches in lamellipodia.[4]
- F-actin binding is essential for coronin 1B function in vivo.[5]
- Coronin 1B coordinates Arp2/3 complex and cofilin activities at the leading edge.[6]
- Phosphorylation of coronin 1B by protein kinase C regulates interaction with Arp2/3 and cell motility.[2]
- In vivo and in vitro characterization of novel neuronal plasticity factors identified following spinal cord injury.[7]
- Isolation, cloning, and characterization of a new mammalian coronin family member, coroninse, which is regulated within the protein kinase C signaling pathway.[8] | https://www.wikidoc.org/index.php/CORO1B | |
5f028d165ddd9a9fb310217b43baef3ed572fe6e | wikidoc | COX4I1 | COX4I1
Cytochrome c oxidase subunit 4 isoform 1, mitochondrial (COX4I1) is an enzyme that in humans is encoded by the COX4I1 gene. COX4I1 is a nuclear-encoded isoform of cytochrome c oxidase (COX) subunit 4. Cytochrome c oxidase (complex IV) is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Antibodies against COX4 can be used to identify the inner membrane of mitochondria in immunfluorescence studies. Mutations in COX4I1 have been associated with COX deficiency and Fanconi anemia.
# Structure
COX4I1 is located on the q arm of chromosome 16 in position 24.1 and has 6 exons. The COX4I1 gene produces a 9.3 kDa protein composed of 83 amino acids. COX4I1 is expressed ubiquitously. The protein encoded by COX4I1 belongs to the cytochrome c oxidase IV family. COX4I1 has a transit peptide domain and acetyl and phosphoprotein amino acid modifications. It is located at the 3' of the NOC4 (neighbor of COX4) gene in a head-to-head orientation, and shares a promoter with it.
# Function
COX4I1 encodes a protein that is located in the inner mitochondrial membrane and is an isoform of the nuclear-encoded subunit IV of cytochrome c oxidase (complex IV), the terminal oxidase in mitochondrial electron transport. Complex IV is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane. The expression of COX4I1, along with COX4I2, may be regulated by oxygen levels, with reduced levels of oxygen leading to increased COX4I2 expression and COX4I1 degradation. This suggests a role for COX4I1 in the optimization of the electron transfer chain under different conditions.
# Clinical Significance
Although relatively little is known about the function of COX4I1, mutations in this gene have been associated with mitochondrial complex IV diseases with severe phenotypes. Among these, COX deficiency and Fanconi anemia have been suspected and linked to mutations in the COX4I1 gene. Clinical features of pathogenic variants of COX4I1 can include short stature, poor weight gain, mild dysmorphic features, mental retardation, spastic paraplegia, severe epilepsy, a narrow and arched palate, malar hypoplasia, little subcutaneous fat, and arachnodactyly. The homozygous mutation K101N and a de novo 16q24.1 interstitial duplication have been found to cause defective COX4I1.
# Interactions
COX4I1 has 153 protein-protein interactions with 142 of them being co-complex interactions. COX4I1 has been found to interact with SDCBP, MT-CO1, IKBKE, TMBIM4, and MCL1. | COX4I1
Cytochrome c oxidase subunit 4 isoform 1, mitochondrial (COX4I1) is an enzyme that in humans is encoded by the COX4I1 gene. COX4I1 is a nuclear-encoded isoform of cytochrome c oxidase (COX) subunit 4. Cytochrome c oxidase (complex IV) is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain.[1][2][3] Antibodies against COX4 can be used to identify the inner membrane of mitochondria in immunfluorescence studies.[4] Mutations in COX4I1 have been associated with COX deficiency and Fanconi anemia.[5][6]
# Structure
COX4I1 is located on the q arm of chromosome 16 in position 24.1 and has 6 exons.[1] The COX4I1 gene produces a 9.3 kDa protein composed of 83 amino acids.[7][8] COX4I1 is expressed ubiquitously. The protein encoded by COX4I1 belongs to the cytochrome c oxidase IV family. COX4I1 has a transit peptide domain and acetyl and phosphoprotein amino acid modifications.[9][10] It is located at the 3' of the NOC4 (neighbor of COX4) gene in a head-to-head orientation, and shares a promoter with it.[1]
# Function
COX4I1 encodes a protein that is located in the inner mitochondrial membrane and is an isoform of the nuclear-encoded subunit IV of cytochrome c oxidase (complex IV), the terminal oxidase in mitochondrial electron transport. Complex IV is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane.[1] The expression of COX4I1, along with COX4I2, may be regulated by oxygen levels, with reduced levels of oxygen leading to increased COX4I2 expression and COX4I1 degradation. This suggests a role for COX4I1 in the optimization of the electron transfer chain under different conditions.[11]
# Clinical Significance
Although relatively little is known about the function of COX4I1, mutations in this gene have been associated with mitochondrial complex IV diseases with severe phenotypes. Among these, COX deficiency and Fanconi anemia have been suspected and linked to mutations in the COX4I1 gene. Clinical features of pathogenic variants of COX4I1 can include short stature, poor weight gain, mild dysmorphic features, mental retardation, spastic paraplegia, severe epilepsy, a narrow and arched palate, malar hypoplasia, little subcutaneous fat, and arachnodactyly. The homozygous mutation K101N and a de novo 16q24.1 interstitial duplication have been found to cause defective COX4I1.[5][6]
# Interactions
COX4I1 has 153 protein-protein interactions with 142 of them being co-complex interactions. COX4I1 has been found to interact with SDCBP, MT-CO1, IKBKE, TMBIM4, and MCL1.[12] | https://www.wikidoc.org/index.php/COX4I1 | |
be81df5d2ee628ca96005cd8e95f2c9e9aa21f89 | wikidoc | COX4I2 | COX4I2
Cytochrome c oxidase subunit 4 isoform 2, mitochondrial is an enzyme that in humans is encoded by the COX4I2 gene. COX4I2 is a nuclear-encoded isoform of cytochrome c oxidase (COX) subunit 4. Cytochrome c oxidase (complex IV) is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Mutations in COX4I2 have been associated with exocrine pancreatic insufficiency, dyserythropoietic anemia, and calvarial hyperostosis (EPIDACH).
# Structure
COX4I2 is located on the q arm of chromosome 20 in position 11.21 and has 6 exons. The COX4I2 gene produces a 20 kDa protein composed of 171 amino acids. The protein encoded by COX4I2 belongs to the cytochrome c oxidase IV family. COX4I2 has a transit peptide domain and a disulfide bond amino acid modification. A Glu138 residue, which corresponds to a Glu136 residue in COX4I1, is believed to be highly conserved and structurally important for the mitochondrial COX response to hypoxia.
# Function
Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. It is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may be involved in the regulation and assembly of the complex. The COX4I2 nuclear gene encodes isoform 2 of subunit IV. Isoform 1 of subunit IV is encoded by a different gene, however, the two genes show a similar structural organization. Subunit IV is the largest nuclear encoded subunit which plays a pivotal role in COX regulation. It is located on the inner mitochondrial membrane on the matrix side. Expression of COX4I2 is highest in the placenta and the lungs. Additionally, the expression of COX4I2, along with COX4I1, may be regulated by oxygen levels, with reduced levels of oxygen leading to increased COX4I2 expression and COX4I1 degradation. This suggests a role for COX4I2 in the optimization of the electron transfer chain under different conditions.
# Clinical Significance
Mutations in COX4I2 have been associated with exocrine pancreatic insufficiency, dyserythropoeitic anemia, and calvarial hyperostosis (EPIDACH). Characteristics of this disease include pancreatic insufficiency, intestinal malabsorption, failure to thrive, and anemia soon after birth. Additional symptoms have included steatorrhea, splenomegaly and hepatomegaly, pancreatic atrophy, generalized muscle hypotonia, hyperostosis, yellowish sclera associated with mild indirect hyperbilirubinemia, impaired coagulation functions, elevated LDH, alanine, and bilirubin, and reduced vitamin E levels. A homozygous mutation, E138K, has been found to result in reduced COX4I2 expression (25% in fibroblasts) and an impaired response to hypoxia. Functional COX4I2 expression below 40% of its normal level is predicted to be rate-limiting, with the E138K mutation occurring in what is believed to be a highly conserved residue of subunit IV.
# Interactions
COX4I2 has been shown to interact with Cytochrome c (CYCS). Additionally, APP, COA3, and KRAS have been found to have protein-protein interactions with COX4I2. | COX4I2
Cytochrome c oxidase subunit 4 isoform 2, mitochondrial is an enzyme that in humans is encoded by the COX4I2 gene.[1][2] COX4I2 is a nuclear-encoded isoform of cytochrome c oxidase (COX) subunit 4. Cytochrome c oxidase (complex IV) is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane, acting as the terminal enzyme of the mitochondrial respiratory chain. Mutations in COX4I2 have been associated with exocrine pancreatic insufficiency, dyserythropoietic anemia, and calvarial hyperostosis (EPIDACH).[3][4]
# Structure
COX4I2 is located on the q arm of chromosome 20 in position 11.21 and has 6 exons.[3] The COX4I2 gene produces a 20 kDa protein composed of 171 amino acids.[5][6] The protein encoded by COX4I2 belongs to the cytochrome c oxidase IV family. COX4I2 has a transit peptide domain and a disulfide bond amino acid modification.[7][8] A Glu138 residue, which corresponds to a Glu136 residue in COX4I1, is believed to be highly conserved and structurally important for the mitochondrial COX response to hypoxia.[4]
# Function
Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. It is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may be involved in the regulation and assembly of the complex. The COX4I2 nuclear gene encodes isoform 2 of subunit IV. Isoform 1 of subunit IV is encoded by a different gene, however, the two genes show a similar structural organization. Subunit IV is the largest nuclear encoded subunit which plays a pivotal role in COX regulation. It is located on the inner mitochondrial membrane on the matrix side. Expression of COX4I2 is highest in the placenta and the lungs.[3][7][8] Additionally, the expression of COX4I2, along with COX4I1, may be regulated by oxygen levels, with reduced levels of oxygen leading to increased COX4I2 expression and COX4I1 degradation. This suggests a role for COX4I2 in the optimization of the electron transfer chain under different conditions.[9]
# Clinical Significance
Mutations in COX4I2 have been associated with exocrine pancreatic insufficiency, dyserythropoeitic anemia, and calvarial hyperostosis (EPIDACH). Characteristics of this disease include pancreatic insufficiency, intestinal malabsorption, failure to thrive, and anemia soon after birth. Additional symptoms have included steatorrhea, splenomegaly and hepatomegaly, pancreatic atrophy, generalized muscle hypotonia, hyperostosis, yellowish sclera associated with mild indirect hyperbilirubinemia, impaired coagulation functions, elevated LDH, alanine, and bilirubin, and reduced vitamin E levels. A homozygous mutation, E138K, has been found to result in reduced COX4I2 expression (25% in fibroblasts) and an impaired response to hypoxia. Functional COX4I2 expression below 40% of its normal level is predicted to be rate-limiting, with the E138K mutation occurring in what is believed to be a highly conserved residue of subunit IV.[7][8][4]
# Interactions
COX4I2 has been shown to interact with Cytochrome c (CYCS).[10][11][12][13] Additionally, APP, COA3, and KRAS have been found to have protein-protein interactions with COX4I2.[14] | https://www.wikidoc.org/index.php/COX4I2 | |
7d5aed5b57f267de965df7766af21f0f88531470 | wikidoc | COX6A1 | COX6A1
Cytochrome c oxidase subunit 6A1, mitochondrial is an protein that in humans is encoded by the COX6A1 gene. Cytochrome c oxidase 6A1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. A mutation of the COX6A1 gene is associated with a recessive axonal or mixed form of Charcot-Marie-Tooth disease.
# Structure
The COX6A1 gene, located on the q arm of chromosome 12 in position 24.2, contains 3 exons and is 2,653 base pairs in length. The COX6A1 protein weighs 12 kDa and is composed of 109 amino acids. The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. This nuclear gene encodes polypeptide 1 (liver isoform) of subunit VIa, and polypeptide 1 is found in all non-muscle tissues. Polypeptide 2 (heart/muscle isoform) of subunit VIa is encoded by a different gene, COX6A2, and is present only in striated muscles. These two polypeptides share 66% amino acid sequence identity.
# Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.
Summary reaction:
# Clinical significance
A mutation leading to a 5 base pair deletion in the COX6A1 gene is associated with Charcot-Marie-Tooth disease (CMT). CMT is the most common inherited neuropathy and can result from mutations in over 30 different loci. Expression of COX6A1 is significantly reduced in affected individuals.
The Trans-activator of transcription protein (Tat) of human immunodeficiency virus (HIV) inhibits cytochrome c oxidase (COX) activity in permeabilized mitochondria isolated from both mouse and human liver, heart, and brain samples. Rapid loss of membrane potential (ΔΨm) occurs with submicromolar doses of Tat, and cytochrome c is released from the mitochondria. | COX6A1
Cytochrome c oxidase subunit 6A1, mitochondrial is an protein that in humans is encoded by the COX6A1 gene. Cytochrome c oxidase 6A1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. A mutation of the COX6A1 gene is associated with a recessive axonal or mixed form of Charcot-Marie-Tooth disease.[1][2]
# Structure
The COX6A1 gene, located on the q arm of chromosome 12 in position 24.2, contains 3 exons and is 2,653 base pairs in length.[1] The COX6A1 protein weighs 12 kDa and is composed of 109 amino acids.[3][4] The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. This nuclear gene encodes polypeptide 1 (liver isoform) of subunit VIa, and polypeptide 1 is found in all non-muscle tissues. Polypeptide 2 (heart/muscle isoform) of subunit VIa is encoded by a different gene, COX6A2, and is present only in striated muscles. These two polypeptides share 66% amino acid sequence identity.[1]
# Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.[1]
Summary reaction:
# Clinical significance
A mutation leading to a 5 base pair deletion in the COX6A1 gene is associated with Charcot-Marie-Tooth disease (CMT). CMT is the most common inherited neuropathy and can result from mutations in over 30 different loci. Expression of COX6A1 is significantly reduced in affected individuals.[6]
The Trans-activator of transcription protein (Tat) of human immunodeficiency virus (HIV) inhibits cytochrome c oxidase (COX) activity in permeabilized mitochondria isolated from both mouse and human liver, heart, and brain samples. Rapid loss of membrane potential (ΔΨm) occurs with submicromolar doses of Tat, and cytochrome c is released from the mitochondria.[7] | https://www.wikidoc.org/index.php/COX6A1 | |
9c21ec8e080eaaab40b9450e009bebe86cf232f7 | wikidoc | COX6A2 | COX6A2
Cytochrome c oxidase subunit VIa polypeptide 2 is a protein that in humans is encoded by the COX6A2 gene. Cytochrome c oxidase 6A2 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.
# Structure
The COX6A2 gene, located on the p arm of chromosome 16 in position 11.12, contains 3 exons and is 698 base pairs in length. The COX6A1 protein weighs 11 kDa and is composed of 97 amino acids. The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. This nuclear gene encodes polypeptide 2 (heart/muscle isoform) of subunit VIa, and polypeptide 2 is present only in striated muscles. Polypeptide 1 (liver isoform) of subunit VIa is encoded by a different gene, COX6A1, and is found in all non-muscle tissues. These two polypeptides share 66% amino acid sequence identity.
# Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.
Summary reaction:
# Clinical significance
The Trans-activator of transcription protein (Tat) of human immunodeficiency virus (HIV) inhibits cytochrome c oxidase (COX) activity in permeabilized mitochondria isolated from both mouse and human liver, heart, and brain samples. Rapid loss of membrane potential (ΔΨm) occurs with submicromolar doses of Tat, and cytochrome c is released from the mitochondria. | COX6A2
Cytochrome c oxidase subunit VIa polypeptide 2 is a protein that in humans is encoded by the COX6A2 gene. Cytochrome c oxidase 6A2 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.[1]
# Structure
The COX6A2 gene, located on the p arm of chromosome 16 in position 11.12, contains 3 exons and is 698 base pairs in length.[1] The COX6A1 protein weighs 11 kDa and is composed of 97 amino acids.[2][3] The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. This nuclear gene encodes polypeptide 2 (heart/muscle isoform) of subunit VIa, and polypeptide 2 is present only in striated muscles. Polypeptide 1 (liver isoform) of subunit VIa is encoded by a different gene, COX6A1, and is found in all non-muscle tissues. These two polypeptides share 66% amino acid sequence identity.[1]
# Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.[1]
Summary reaction:
# Clinical significance
The Trans-activator of transcription protein (Tat) of human immunodeficiency virus (HIV) inhibits cytochrome c oxidase (COX) activity in permeabilized mitochondria isolated from both mouse and human liver, heart, and brain samples. Rapid loss of membrane potential (ΔΨm) occurs with submicromolar doses of Tat, and cytochrome c is released from the mitochondria.[5] | https://www.wikidoc.org/index.php/COX6A2 | |
eb9671b7f221970080d24e8e9f70b70a2656878d | wikidoc | COX6B1 | COX6B1
Cytochrome c oxidase subunit 6B1 is an enzyme that in humans is encoded by the COX6B1 gene. Cytochrome c oxidase 6B1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. Mutations of the COX6B1 gene are associated with severe infantile encephalomyopathy and mitochondrial complex IV deficiency (MT-C4D).
# Structure
The COX6B1 gene, located on the q arm of chromosome 19 in position 13.1, contains 4 exons and is 10,562 base pairs in length. The COX6B1 protein weighs 10 kDa and is composed of 86 amino acids. The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes, and multiple structural subunits encoded by nuclear genes.
# Function
Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. It is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may be involved in the regulation and assembly of the complex. This nuclear gene encodes subunit VIb. Three pseudogenes COX6BP-1, COX6BP-2 and COX6BP-3 have been found on chromosomes 7, 17 and 22q13.1-13.2, respectively.
Summary reaction:
# Clinical significance
Mutations affecting the COX6B1 gene are associated with mitochondrial complex IV deficiency (MT-C4D), a disorder of the mitochondrial respiratory chain with heterogeneous clinical manifestations, ranging from isolated myopathy to severe multisystem disease affecting several tissues and organs. Features include hypertrophic cardiomyopathy, hepatomegaly and liver dysfunction, hypotonia, muscle weakness, exercise intolerance, developmental delay, delayed motor development, and mental retardation. Some affected individuals manifest a fatal hypertrophic cardiomyopathy resulting in neonatal death. A subset of patients manifest Leigh's syndrome. A COX6B1 R20C missense mutation has been linked to complex IV deficiency with encephalomyopathy, hydrocephalus, and hypertrophic cardiomyopathy.
# Interactions
COX6B1 has been shown to have 548 binary protein-protein interactions including 547 co-complex interactions. | COX6B1
Cytochrome c oxidase subunit 6B1 is an enzyme that in humans is encoded by the COX6B1 gene.[1] Cytochrome c oxidase 6B1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. Mutations of the COX6B1 gene are associated with severe infantile encephalomyopathy and mitochondrial complex IV deficiency (MT-C4D).[2]
# Structure
The COX6B1 gene, located on the q arm of chromosome 19 in position 13.1, contains 4 exons and is 10,562 base pairs in length.[2] The COX6B1 protein weighs 10 kDa and is composed of 86 amino acids.[3][4] The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes, and multiple structural subunits encoded by nuclear genes.[2]
# Function
Cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain, catalyzes the electron transfer from reduced cytochrome c to oxygen. It is a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. The mitochondrially-encoded subunits function in electron transfer, and the nuclear-encoded subunits may be involved in the regulation and assembly of the complex. This nuclear gene encodes subunit VIb. Three pseudogenes COX6BP-1, COX6BP-2 and COX6BP-3 have been found on chromosomes 7, 17 and 22q13.1-13.2, respectively.[2]
Summary reaction:
# Clinical significance
Mutations affecting the COX6B1 gene are associated with mitochondrial complex IV deficiency (MT-C4D), a disorder of the mitochondrial respiratory chain with heterogeneous clinical manifestations, ranging from isolated myopathy to severe multisystem disease affecting several tissues and organs. Features include hypertrophic cardiomyopathy, hepatomegaly and liver dysfunction, hypotonia, muscle weakness, exercise intolerance, developmental delay, delayed motor development, and mental retardation. Some affected individuals manifest a fatal hypertrophic cardiomyopathy resulting in neonatal death. A subset of patients manifest Leigh's syndrome.[6] A COX6B1 R20C missense mutation has been linked to complex IV deficiency with encephalomyopathy, hydrocephalus, and hypertrophic cardiomyopathy.[7]
# Interactions
COX6B1 has been shown to have 548 binary protein-protein interactions including 547 co-complex interactions.[8] | https://www.wikidoc.org/index.php/COX6B1 | |
a4c7952fcbd7cfa9729773c07cf4f9e7ef825558 | wikidoc | COX6B2 | COX6B2
Cytochrome c oxidase subunit VIb polypeptide 2 is a protein that in humans is encoded by the COX6B2 gene. Cytochrome c oxidase 6B2 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.
# Structure
The COX6B2 gene, located on the q arm of chromosome 19 in position 13.42, contains 5 exons and is 5,113 base pairs in length. The protein encoded by the COX6B2 gene weighs 11 kDa and is composed of 88 amino acids. The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes.
# Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.
Summary reaction: | COX6B2
Cytochrome c oxidase subunit VIb polypeptide 2 is a protein that in humans is encoded by the COX6B2 gene. Cytochrome c oxidase 6B2 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.[1]
# Structure
The COX6B2 gene, located on the q arm of chromosome 19 in position 13.42, contains 5 exons and is 5,113 base pairs in length.[1] The protein encoded by the COX6B2 gene weighs 11 kDa and is composed of 88 amino acids.[2][3] The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes.[1]
# Function
Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.[1]
Summary reaction: | https://www.wikidoc.org/index.php/COX6B2 | |
15294d5fa1e452bd73efd0edcd9093a4c6951d71 | wikidoc | CPPene | CPPene
# Overview
CPPene is a potent competitive antagonist at the NMDA receptor. It was originally designed as a potential therapy for excitotoxicity, epilepsy or neuropathic pain. It looked very promising in in vitro trials proving to be a potent competitive antagonist at the NMDA without affecting other receptors. It's promise continued through to in vitro tissue culture studies where it proved to limit damage after occluding the middle cerebral artery leading to ischaemia. It also blocked photosensitive epilepsies in Baboons.
CPPene has a pharmacokinetic profile suitable of progressing to clinical trials as it has no toxic by products, is excreted exclusively via the renal system and remains unchanged in the brain.
However CPPene was removed from clinical trials as it provided no suitable neuronal protection or beneficial treatment for epilepsy. The reasons behind this is the relatively short therapeutic time window following ischaemic damage and a small amount of glutamate helps neuronal survival. It is also believed that some "pro-survival" genes are activated by NMDA receptors.
Possible directions for future development is via specific AMPA, Kainate of mGlu R subunits leading to more specific responses.
- ↑ Dr David Jane | CPPene
# Overview
CPPene is a potent competitive antagonist at the NMDA receptor. It was originally designed as a potential therapy for excitotoxicity, epilepsy or neuropathic pain. It looked very promising in in vitro trials proving to be a potent competitive antagonist at the NMDA without affecting other receptors. It's promise continued through to in vitro tissue culture studies where it proved to limit damage after occluding the middle cerebral artery leading to ischaemia. It also blocked photosensitive epilepsies in Baboons.
CPPene has a pharmacokinetic profile suitable of progressing to clinical trials as it has no toxic by products, is excreted exclusively via the renal system and remains unchanged in the brain.
However CPPene was removed from clinical trials as it provided no suitable neuronal protection or beneficial treatment for epilepsy. The reasons behind this is the relatively short therapeutic time window following ischaemic damage and a small amount of glutamate helps neuronal survival. It is also believed that some "pro-survival" genes are activated by NMDA receptors.
Possible directions for future development is via specific AMPA, Kainate of mGlu R subunits leading to more specific responses.[1]
- ↑ Dr David Jane
Template:WH
Template:WS | https://www.wikidoc.org/index.php/CPPene | |
89809ab0b537b7a1c16545d08ce10e0feb6a84bf | wikidoc | CRABP1 | CRABP1
Cellular retinoic acid-binding protein 1 is a protein that in humans is encoded by the CRABP1 gene.
CRABP1 is assumed to play an important role in retinoic acid-mediated differentiation and proliferation processes. It is structurally similar to the cellular retinol-binding proteins, but binds only retinoic acid. CRABP1 is constitutively expressed and is believed to have different functions in the cell than the related CRABP2.
# Function
CRABP1 binds to retinoid acid and helps to transport it into cells (Figure 1). Both CRABP1 and CRABP2 perform this activity. The retinoic acid molecule is then released and further bound to retinoic acid receptor (RAR) and the retinoid X receptor (RXR) as homodimers or heterodimers. This complex then further binds to retinoic acid response elements (RARE) on DNA that regulates transcription of retinoid acid dependent null genes. The domains for the nuclear localization and the retinoic acid binding are shown in Figure 3.
CRABP1 has been found to be involved in multiple cancer proliferation pathways. CRABP1 activates the extracellular signal-regulated kinase, ERK1 and ERK2 kinases, which are involved in the cell cycle. CRABP1 activity can thus extend the cell cycle, e.g. in embryonic and neural stem cells. Knockout mice without CRABP1 showed increased neural stem cell proliferation and thus hippocampus neurogenesis. Furthermore, learning and memory were improved in knockout mice, as measured by the Morris water maze test and an object recognition task.
CRABP1 is also involved in cancer cell apoptosis. trans-retinoic acid was considered a as a ligand of CRABP1. It was observed that CRABP1 regulated extracellular signal regulated kinase (ERK1/2) which in turn activates the protein phosphatase 2A (PP2A) that induces apoptosis of cancer cells and lengthens the cell cycle of embryonic stem cells. PP2A activity promotes the stem cells renewal ability during the differentiation process. When CRABP1 was knocked down the apoptotic induction ability was also removed and allowed for cell proliferation. The re-expression of CRABP1 in CRABP1 null cells brought back the induced apoptotic activity. Thus CRABP1 may be used as a therapeutic target along with trans-retinoic acid for apoptotic activity within cancer cells. Figure 2 illustrates both pathways of retinoic acid binding to CRABP for cell proliferation and apoptotic activity. | CRABP1
Cellular retinoic acid-binding protein 1 is a protein that in humans is encoded by the CRABP1 gene.[1][2]
CRABP1 is assumed to play an important role in retinoic acid-mediated differentiation and proliferation processes. It is structurally similar to the cellular retinol-binding proteins, but binds only retinoic acid. CRABP1 is constitutively expressed and is believed to have different functions in the cell than the related CRABP2.[2]
# Function
CRABP1 binds to retinoid acid and helps to transport it into cells (Figure 1). Both CRABP1 and CRABP2 perform this activity. The retinoic acid molecule is then released and further bound to retinoic acid receptor (RAR) and the retinoid X receptor (RXR) as homodimers or heterodimers. This complex then further binds to retinoic acid response elements (RARE) on DNA that regulates transcription of retinoid acid dependent null genes.[6] The domains for the nuclear localization and the retinoic acid binding are shown in Figure 3.
CRABP1 has been found to be involved in multiple cancer proliferation pathways. CRABP1 activates the extracellular signal-regulated kinase, ERK1 and ERK2 kinases, which are involved in the cell cycle. CRABP1 activity can thus extend the cell cycle, e.g. in embryonic and neural stem cells. Knockout mice without CRABP1 showed increased neural stem cell proliferation and thus hippocampus neurogenesis. Furthermore, learning and memory were improved in knockout mice, as measured by the Morris water maze test and an object recognition task.[7]
CRABP1 is also involved in cancer cell apoptosis. trans-retinoic acid was considered a [null therapeutic target for cancer] as a ligand of CRABP1.[8] It was observed that CRABP1 regulated extracellular signal regulated kinase (ERK1/2) which in turn activates the protein phosphatase 2A (PP2A) that induces apoptosis of cancer cells and lengthens the cell cycle of embryonic stem cells. PP2A activity promotes the stem cells renewal ability during the differentiation process. When CRABP1 was knocked down the apoptotic induction ability was also removed and allowed for cell proliferation. The re-expression of CRABP1 in CRABP1 null cells brought back the induced apoptotic activity. Thus CRABP1 may be used as a therapeutic target along with trans-retinoic acid for apoptotic activity within cancer cells.[8] Figure 2 illustrates both pathways of retinoic acid binding to CRABP for cell proliferation and apoptotic activity. | https://www.wikidoc.org/index.php/CRABP1 | |
0c3a1cbb7d0b71891d546dca4108c2ded942654c | wikidoc | CRABP2 | CRABP2
Cellular retinoic acid-binding protein 2 is a cytoplasmic binding protein that in humans is encoded by the CRABP2 gene.
CRABP2 is structurally similar to CRABP1, but CRABP2 has a lower affinity for retinoic acid (RA). CRABP2 is associated with cells that produce large amounts of retinoic acid and may play a role in mediating the effects of retinoic acid in the cell.
# Function
A number of specific carrier proteins for members of the vitamin A family have been discovered. Retinoic acid is an active metabolite of vitamin A (retinol). Cellular retinoic acid binding proteins (CRABP) are low molecular weight proteins whose precise function remains largely unknown.
The inducibility of the CRABP2 gene suggests that this isoform is important in retinoic acid-mediated regulation of human skin growth, differentiation and development. CRABP2 is involved in the metabolism and transportation of retinoic acid from the cytosol to the RARs (retinoic acid receptors) located in the nucleus. CRABP2 is specifically co-expressed with RAR-β and cellular retinol binding protein 1 genes in certain tissues. It has been postulated that the CRABP2 gene is transcriptionally regulated by a newly synthesized regulatory protein.
# Tissue distribution
Tissue distribution of the CRABP2 gene has primarily been studied using mouse models. During embryonic development, CRABP2 is present in tissues throughout the body in a more diffuse pattern than CRABP1. CRABP1 is more isolated to specific regions, though it does appear in higher concentrations. CRABP1 and 2 often overlap in tissues.
CRABP2 gene expression is abundant in the trunk and hindbrain (and to a lesser extent the forebrain), but are present in other areas of the body. Structures such as the limbs, hindbrain and cranial neural crest cells have been shown to be excessively sensitive to high levels of retinoic acid. Rhombomere segmentation in the hindbrain and the development of cranial ganglia V, VII, VIII, IX, and X also appear to be partially dependent on CRABP2 expression. CRABP2 is abundant in the dorsal part of the limb during development.
CRABP2 genes are also expressed in structures that are less sensitive to retinoid levels throughout the body during embryonic development. These structures include the pharyngeal pouches, foregut, midgut, mandibular and frontal mesenchyme, developing muscle, interdigital mesenchyme, the urogenital system, optic vessels, and inner ear sensory epithelium.
# Defects
Vitamin A deficiency in mice has been shown to cause problems with spermatogenesis, irregular estrous cycles, changes in the uterine epithelium and reproductive failure ending with fetal death and reabsorption.
Tissues with CRABP2 can be sensitive to high levels of retinoic acid which may cause defects in the development of those tissues.
CRABP2 gene knockout studies should be performed to determine any specific defects caused by loss of this gene.
# Interactions
CRABP2 has been shown to interact with Cyclin D3. | CRABP2
Cellular retinoic acid-binding protein 2 is a cytoplasmic binding protein that in humans is encoded by the CRABP2 gene.[1][2][3]
CRABP2 is structurally similar to CRABP1, but CRABP2 has a lower affinity for retinoic acid (RA).[1] CRABP2 is associated with cells that produce large amounts of retinoic acid and may play a role in mediating the effects of retinoic acid in the cell.[1][4]
# Function
A number of specific carrier proteins for members of the vitamin A family have been discovered. Retinoic acid is an active metabolite of vitamin A (retinol).[4] Cellular retinoic acid binding proteins (CRABP) are low molecular weight proteins whose precise function remains largely unknown.
The inducibility of the CRABP2 gene suggests that this isoform is important in retinoic acid-mediated regulation of human skin growth, differentiation and development. CRABP2 is involved in the metabolism and transportation of retinoic acid from the cytosol to the RARs (retinoic acid receptors) located in the nucleus.[1][3][4][5] CRABP2 is specifically co-expressed with RAR-β and cellular retinol binding protein 1 genes in certain tissues.[1] It has been postulated that the CRABP2 gene is transcriptionally regulated by a newly synthesized regulatory protein.[3]
# Tissue distribution
Tissue distribution of the CRABP2 gene has primarily been studied using mouse models. During embryonic development, CRABP2 is present in tissues throughout the body in a more diffuse pattern than CRABP1.[1] CRABP1 is more isolated to specific regions, though it does appear in higher concentrations.[1] CRABP1 and 2 often overlap in tissues.[1]
CRABP2 gene expression is abundant in the trunk and hindbrain (and to a lesser extent the forebrain), but are present in other areas of the body.[1] Structures such as the limbs, hindbrain and cranial neural crest cells have been shown to be excessively sensitive to high levels of retinoic acid.[1] Rhombomere segmentation in the hindbrain and the development of cranial ganglia V, VII, VIII, IX, and X also appear to be partially dependent on CRABP2 expression.[1] CRABP2 is abundant in the dorsal part of the limb during development.[1]
CRABP2 genes are also expressed in structures that are less sensitive to retinoid levels throughout the body during embryonic development.[1] These structures include the pharyngeal pouches, foregut, midgut, mandibular and frontal mesenchyme, developing muscle, interdigital mesenchyme, the urogenital system, optic vessels, and inner ear sensory epithelium.[1]
# Defects
Vitamin A deficiency in mice has been shown to cause problems with spermatogenesis, irregular estrous cycles, changes in the uterine epithelium and reproductive failure ending with fetal death and reabsorption.[4]
Tissues with CRABP2 can be sensitive to high levels of retinoic acid which may cause defects in the development of those tissues.[1]
CRABP2 gene knockout studies should be performed to determine any specific defects caused by loss of this gene.
# Interactions
CRABP2 has been shown to interact with Cyclin D3.[6] | https://www.wikidoc.org/index.php/CRABP2 | |
9f66da7228fc125bab17f9b35bc374cacbc584e6 | wikidoc | CRYBB2 | CRYBB2
Beta-crystallin B2 is a protein that in humans is encoded by the CRYBB2 gene.
# Function
Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N-terminal and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, is part of a gene cluster with beta-A4, beta-B1, and beta-B3. A chain-terminating mutation was found to cause type 2 cerulean cataracts.
# Interactions
CRYBB2 has been shown to interact with Hsp27, CRYGC, CRYAA and CRYAB. | CRYBB2
Beta-crystallin B2 is a protein that in humans is encoded by the CRYBB2 gene.[1][2][3]
# Function
Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N-terminal and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, is part of a gene cluster with beta-A4, beta-B1, and beta-B3. A chain-terminating mutation was found to cause type 2 cerulean cataracts.[3]
# Interactions
CRYBB2 has been shown to interact with Hsp27,[4] CRYGC,[4] CRYAA[4] and CRYAB.[4] | https://www.wikidoc.org/index.php/CRYBB2 | |
c862a6cbc37642eec52d5d330b9adf0f2699d006 | wikidoc | CSNK1D | CSNK1D
The CSNK1D gene encodes the casein kinase I isoform delta enzyme in humans.
This gene is a member of the casein kinase I (CKI) gene family whose members have been implicated in the control of cytoplasmic and nuclear processes, including DNA replication and repair. The encoded protein is highly similar to the mouse and rat CK1 delta homologs. Two transcript variants encoding different isoforms have been found for this gene.
# Interactions
CSNK1D has been shown to interact with Gap junction protein, alpha 1. | CSNK1D
The CSNK1D gene encodes the casein kinase I isoform delta enzyme in humans.[1]
This gene is a member of the casein kinase I (CKI) gene family whose members have been implicated in the control of cytoplasmic and nuclear processes, including DNA replication and repair. The encoded protein is highly similar to the mouse and rat CK1 delta homologs. Two transcript variants encoding different isoforms have been found for this gene.[2]
# Interactions
CSNK1D has been shown to interact with Gap junction protein, alpha 1.[3] | https://www.wikidoc.org/index.php/CSNK1D | |
53b9a032b50a1694400498e269f2e5ffe33379fd | wikidoc | CSNK2B | CSNK2B
Casein kinase II subunit beta is a protein that in humans is encoded by the CSNK2B gene.
This gene encodes the beta subunit of casein kinase II, a ubiquitous protein kinase which regulates metabolic pathways, signal transduction, transcription, translation, and replication. The enzyme localizes to the endoplasmic reticulum and the Golgi apparatus.
Casein kinase, a ubiquitous, well-conserved protein kinase involved in cell metabolism and differentiation, is characterised by its preference for Serine or Threonine in acidic stretches of amino acids. The enzyme is a tetramer of 2 alpha- and 2 beta-subunits. However, some species (e.g., mammals) possess 2 related forms of the alpha-subunit (alpha and alpha'), while others (e.g., fungi) possess 2 related beta-subunits (beta and beta'). The alpha-subunit is the catalytic unit and contains regions characteristic of serine/threonine protein kinases. The beta-subunit is believed to be regulatory, possessing an N-terminal auto-phosphorylation site, an internal acidic domain, and a potential metal-binding motif. The beta subunit is a highly conserved protein of about 25kDa that contains, in its central section, a cysteine-rich motif, CX(n)C, that could be involved in binding a metal such as zinc. The mammalian beta-subunit gene promoter shares common features with those of other mammalian protein kinases and is closely related to the promoter of the regulatory subunit of cAMP-dependent protein kinase.
# Interactions
CSNK2B has been shown to interact with CD163, CSNK2A2, Casein kinase 2, alpha 1, FGF1, TRIB3, CDC34, Ribosomal protein L5, BTF3, BRCA1, RNF7, P70-S6 Kinase 1 and APC. | CSNK2B
Casein kinase II subunit beta is a protein that in humans is encoded by the CSNK2B gene.[1][2]
This gene encodes the beta subunit of casein kinase II, a ubiquitous protein kinase which regulates metabolic pathways, signal transduction, transcription, translation, and replication. The enzyme localizes to the endoplasmic reticulum and the Golgi apparatus.[3]
Casein kinase, a ubiquitous, well-conserved protein kinase involved in cell metabolism and differentiation, is characterised by its preference for Serine or Threonine in acidic stretches of amino acids. The enzyme is a tetramer of 2 alpha- and 2 beta-subunits.[4][5] However, some species (e.g., mammals) possess 2 related forms of the alpha-subunit (alpha and alpha'), while others (e.g., fungi) possess 2 related beta-subunits (beta and beta').[6] The alpha-subunit is the catalytic unit and contains regions characteristic of serine/threonine protein kinases. The beta-subunit is believed to be regulatory, possessing an N-terminal auto-phosphorylation site, an internal acidic domain, and a potential metal-binding motif.[6] The beta subunit is a highly conserved protein of about 25kDa that contains, in its central section, a cysteine-rich motif, CX(n)C, that could be involved in binding a metal such as zinc.[7] The mammalian beta-subunit gene promoter shares common features with those of other mammalian protein kinases and is closely related to the promoter of the regulatory subunit of cAMP-dependent protein kinase.[6]
# Interactions
CSNK2B has been shown to interact with CD163,[8] CSNK2A2,[9][10][11][12] Casein kinase 2, alpha 1,[10][11][12][13][14] FGF1,[15] TRIB3,[16] CDC34,[17] Ribosomal protein L5,[9][13][18][19] BTF3,[20] BRCA1,[21] RNF7,[13] P70-S6 Kinase 1[22] and APC.[23] | https://www.wikidoc.org/index.php/CSNK2B | |
3c087cc2b660a8fb35712d071aee589da2437c59 | wikidoc | CS gas | CS gas
CS gas is the common name for 2-chlorobenzalmalononitrile (also called o-Chlorobenzylidene Malononitrile) (chemical formula: C10H5ClN2), a substance that is used as a riot control agent and is generally accepted as being non-lethal. CS was discovered by two Americans, Ben Corson and Roger Staughton, at Middlebury College in 1928, and the chemical gets its name from the first letters of the scientists' surnames. The compound is actually a solid at room temperature, though it is used as an aerosol.
CS was developed and tested secretly at Porton Down in Wiltshire, England, in the 1950s and 1960s. CS was used first on animals, then subsequently on British Army servicemen volunteers. Notably, CS has a limited effect on animals due to "under-developed tear-ducts and protection by fur".
# Production
CS is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile via the Knoevenagel condensation:
The reaction is catalysed with weak base like piperidine or pyridine. The production method has not changed since the substance was discovered by Carson and Staughton. Other bases, solvent free methods and microwave promotion have been suggested to improve the production of the substance.
The physiological properties have been discovered already by the chemists first synthesising the compound in 1928:
"Physiological Properties – Certain of these dinitriles have the effect of sneeze and tear gases. They are harmless when wet but to handle the dry powder is disastrous. (sic)"
## Use as an aerosol
As 2-chlorobenzalmalononitrile is a solid at room temperature, not a gas, a variety of techniques have been used to make this solid usable as an aerosol:
- Melted and sprayed in the molten form.
- Dissolved in organic solvent.
- CS2 dry powder (CS2 is a siliconized, micro-pulverized form of CS).
- CS from thermal grenades by generation of hot gases.
In the Waco Siege, CS was dissolved in the organic solvent dichloromethane (also known as methylene chloride). When the volatile dichlormethane evaporated, the CS crystallized with the dichloromethane molecules as an aerosol. Another method typically used for grenades is to combine CS with a pyrotechnic composition which burns to generate an aerosol of CS-laden smoke. As the smoke disperses, tiny CS crystals 'ride' the smoke molecules to their targets, where they affect the eyes, nose, throat and skin causing extreme irritation.
# Effects
Many types of tear gas and other Riot Control Agents have been produced with effects ranging from mild tearing of the eyes to immediate vomiting and prostration. CN and CS are the most widely used and known, but around 15 different types of tear gas have been developed worldwide e.g. Adamsite or Bromoacetone, CNB, and CNC. CS has become the most popular due to its strong effect and lack of toxicity in comparison with other similar chemical agents. The effect of CS on a person will depend on whether it is packaged as a solution or used as an aerosol; the size of solution droplets and the size of the CS particulates after evaporation are factors determining its effect on the human body. Certain individuals, however, have been found to be particularly sensitive to CS and/or the organic solvents that are utilized. Studies on the use of CS on the public have noted that it may be ineffective against persons who are either mentally ill or who are under the effects of drugs and alcohol.
Persons who have had contact with CS sometimes develop allergic contact dermatitis, even with blisters and crust.
Studies show that most of the effects are of a relative short term, but individuals notice some mild effects even after months.
The chemical reacts with moisture on the skin and in the eyes causing a burning sensation and the immediate forceful and uncontrollable shutting of the eyes. Reported effects can include tears streaming from the eyes, running nose full of mucus, burning in the nose and throat areas, disorientation, dizziness and restricted breathing. In highly concentrated doses it can also induce severe coughing and vomiting. Almost all of the immediate effects wear off in a matter of minutes.
# Use
CS is used in spray form by many police forces as a temporary incapacitant and to subdue attackers or persons who are violently aggressive. Officers that are trained in the use and application of CS spray are routinely exposed to it as part of their training.
Recently, blank pistol cartridges carrying CS in powder form have been released to public. These, when fired in relatively close ranges, fully expose the target to the effects of CS, and are employed as a potent defensive weapon in regions where blank firing pistols are legally permitted for such use.
Although predominantly used by police it has also been used in criminal attacks in various countries.
Use of CS in war is prohibited under the terms of the 1997 Chemical Weapons Convention (signed in 1993) because it could trigger retaliation with more toxic agents such as nerve gas. Domestic police use of CS, however, is legal in many countries.
## Cyprus
CS was first tested in the field by the British army in Cyprus in 1958. At this time it was known by the code name T792.
## Vietnam
It has been reported that thousands of tons of CS gas were used by the U.S. forces in Vietnam to bring Viet Cong into the open, other estimates report 15 million pounds (7500 tons) of CS being used. It was also used by the North Vietnamese forces in some battles like Hue in 1968 or during the Easter Offensive in 1972.
## Northern Ireland
CS gas was used extensively in the Bogside area of Derry, Northern Ireland during the "Battle of the Bogside", a two-day riot in August, 1969. A total of 1,091 canisters containing 12.5g of CS each, and 14 canisters containing 50g of CS each, were released in the densely populated residential area. On 30 August the Himsworth Inquiry was set up to investigate the medical effects of its use in Derry. Its conclusions, viewed in the political context of the time, still pointed towards the necessity of further testing of CS gas before being used as a riot control agent. During the rioting in Belfast, the following year, known as the Falls Curfew, the Army fired up to 1,600 canisters into the densely populated Falls Road area. Not long after, the British Army and RUC ceased using CS in Northern Ireland. Up to this point, it had been used in crowd control scenarios in Derry and Belfast.
## Iraq
Iraq successfully developed CS during the 1970s and during the 1980s produced tons of the substance firstly at Salman Pak and later at al-Muthanna. Saddam Hussein used CS against the Kurds in his own country and against Iran during the Iran-Iraq War. Blackwater Worldwide, acting as an agent of the United States, deployed CS in the Iraq War from a helicopter hovering over a checkpoint in the Green Zone in Bagdhad.
## Philippines
CS tear gas was used in submersion of the mutiny in Makati that was led by Sen. Antonio Trillanes. The tear gas was fired in the building and all the people in the building including reporters were affected.
## England, Scotland & Wales
CS tear gas was first used in mainland Britain to quell rioting in the Toxteth area of Liverpool in 1981.
Personal incapacitant spray (PIS) was sanctioned for use by police in England and Wales in 1995. The CS preparation in this case is CS dissolved in the organic solvent MiBK, or methyl iso-butyl ketone, an industrial de-greasing agent. The aerosol propellant used in this preparation is nitrogen. Officers in Scotland carry CS spray on their belt.
It has been noted that the solvent MiBK is itself harmful, and can cause inflammation, dermatitis, burns to the skin and liver damage.
A six month trial by 16 police forces in England began on the 1 March 1996. Only two weeks later, on 16 March 1996, a Gambian asylum seeker, Ibrahima Sey was taken to Ilford Police Station in East London. Whilst incapacitating the man, police sprayed him with CS and held him on the ground for over 15 minutes. The man died, the case was taken to court and although a verdict of "unlawful killing" was given by the jury at the end of the inquiry into his death, no charges were brought against any member of the police force.
The forces that do use the PIS in the UK require that police constables should themselves be sprayed with a 3% dissolved CS, during self-defense training, in order for them to be able to be authorized to carry it as personal protection equipment. They are also trained in helping the incapacitated person recover quickly once successfully restrained. Most forces currently issue CS spray to its officers, but there has been a recent move for a few forces to issue PAVA Spray (pelargonic acid vanillylamide aka nonivamide).
The CS spray used by UK police has 5 times as much CS as the spray used by American police forces (5% dissolved CS and 1% CS respectively).
In 1999 the UK mental health charity MIND called for a suspension in its use until it is fully tested and there is proof that CS is safe.
More recently, in February 2006, there were calls to have CS spray banned in the UK after Dan Ford, from Wareham in Dorset, was permanently facially scarred after being sprayed in the face with a police CS canister. Mr Ford was subsequently advised by doctors to stay out of sunlight for at least 12 months. About the incident, his cousin, Donna Lewis, was quoted as saying, "To look at him, it was like looking at a melting man, with liquid oozing from his face."
However, it is not yet confirmed that Mr Ford's injury is a reaction to having been exposed to police CS spray, or whether an unrelated chemical exposure has caused the injury. An investigation is ongoing.
The British Armed Forces use CS gas annually to test their CBRN equipment. During initial training they introduce recruits to CS gas by ordering them into a small enclosed space known as a Respirator Test Facility (RTF) and igniting chemical tablets to induce CS production. When recruits have carried out their CBRN drills (which include immediate actions for decontamination, an eating drill, a drinking drill and a gas mask canister change) the NCO in charge of the RTF will order them to remove their respirators and inhale the CS. This is apparently to inform the trainees of what CS effects feel like, so they can have trust in their equipment and procedures, thus proving to themselves that it works in the contaminated environment in training, and are then able to take this confidence to the battlefield environment.
In 2005, a student from Mayfield School in Essex, used CS Gas inside a school. Several students were taken to A&E, but all survived. The remaining students of the school were held in classrooms and halls, until it was confirmed by the local police and firefighters that the scene was safe. The event was reported only in a local newspaper, the Ilford Recorder.
## United States
CS is used by many police forces within the United States. It was most infamously used as one of a number of techniques by FBI law enforcement officials in the 1993 Waco Siege.
Members of the US armed forces are exposed to CS during initial training, and during training refresher courses or equipment maintenance exercises, using CS tablets that are melted on a hotplate. This is to demonstrate the importance of properly wearing a gas mask or a Protective mask, as the agent's presence quickly reveals an improper fit or seal of the mask's rubber gaskets against the face. These exercises also encourage confidence in the ability of the equipment to protect the wearer from such chemical attacks. Basic Combat Trainees in the United States Army are always exposed in a gas-chamber environment using the tablet form, and often the Drill Sergeants put them in formation near the end of their 9 week cycle and throw CS grenades at them.
## Elsewhere
CS was used in large quantities to quell a protest in Lusaka, Zambia in July 1997 and the 1999 WTO protest in Seattle. Amnesty International reported that it had been manufactured by the UK company Pains-Wessex. Subsequently, Amnesty called for an export ban when the receiving regime is either not fully trained in the use of CS, or had shown usage "contrary to the manufacturer’s instructions".
In September 2000, the Guardian Newspaper revealed how a UK company, HPP, used legal loopholes to export CS to a private security company in Rwanda, in breach of United Nations sanctions. The Guardian also reported that CS was used by the Hutu militia in Rwanda to flush Tutsis out of buildings before hacking them to death.
CS has been used by the government in South Africa; by Israel against Palestinians and Israelis; by the South Korean government in Seoul, and during the Balkan conflicts by Serbia.
CS tear gas was used at the G8 protests in Genoa, Italy and Quebec, Canada during the FTAA anti-globalization demonstrations during the Quebec City Summit of the Americas.
The Canadian, Norwegian and Australian Armies train their soldiers with CS gas in a manner similar to that of the USA, as it is a basic part of NBC (nuclear, biological, chemical) or more recently within NATO, CBRN (Chemical, Biological, Radiological, Nuclear) training. Gas is released by burning tablets, usually in a tent or a small building reserved for this purpose (a "gas hut"), and soldiers are exposed to it on three occasions. During the first two exposures the soldier enters the tent or gas hut wearing a gas mask. During the first exposure he removes his gas mask and leaves the tent or hut. During the second exposure he must remove the mask, receive facial exposure, then replace and clear the mask. In the third exposure he enters the tent unprotected, must fit and clear the gas mask before leaving. Other drills such as drinking and under-mask decontamination are usually also practised yearly. Symptoms are a burning sensation on any moist skin, whether due to perspiration or other fluids such as tears or in the nasal membranes.
# Toxicity
Although described as a non-lethal weapon for crowd control, many studies have raised doubts about this classification. As well as creating severe pulmonary damage, CS can also significantly damage the heart and liver.
On September 28, 2000, Prof. Dr. Uwe Heinrich released a study commissioned by John C. Danforth, of 'The Office of Special Counsel', to investigate the use of CS by the FBI at the Branch Davidians' Mount Carmel compound. He concluded that the lethality of CS used would have been determined mainly by two factors: whether gas masks were used and whether the occupants were trapped in a room. He suggests that if no gas masks were used and the occupants were trapped, then, "...there is a distinct possibility that this kind of CS exposure can significantly contribute to or even cause lethal effects."
Many reports have associated CS exposure with miscarriages, this is consistent with its reported clastogenic effect (abnormal chromosome change) on mammalian cells.
When CS is metabolized, cyanide can be detected in human tissue. According to the United States Army Center for Health Promotion and Preventive Medicine, CS emits "very toxic fumes" when heated to decomposition, and at specified concentrations CS gas is an immediate danger to life and health. They also state that those exposed to CS gas should seek medical attention immediately.
# Decontamination
CS contamination can be removed by washing with an alkaline solution of water and 5% sodium bisulfite. A quick way to decontaminate the eyes is to pour cow's milk into them. Vision will be restored although breathing difficulties and pain will persist. | CS gas
Template:Chembox new
CS gas is the common name for 2-chlorobenzalmalononitrile (also called o-Chlorobenzylidene Malononitrile) (chemical formula: C10H5ClN2), a substance that is used as a riot control agent and is generally accepted as being non-lethal. CS was discovered by two Americans, Ben Corson and Roger Staughton, at Middlebury College in 1928, and the chemical gets its name from the first letters of the scientists' surnames.[1] The compound is actually a solid at room temperature, though it is used as an aerosol.
CS was developed and tested secretly at Porton Down in Wiltshire, England, in the 1950s and 1960s. CS was used first on animals, then subsequently on British Army servicemen volunteers. Notably, CS has a limited effect on animals due to "under-developed tear-ducts and protection by fur".[2]
# Production
CS is synthesized by the reaction of 2-chlorobenzaldehyde and malononitrile via the Knoevenagel condensation:
The reaction is catalysed with weak base like piperidine or pyridine. The production method has not changed since the substance was discovered by Carson and Staughton.[3] Other bases, solvent free methods and microwave promotion have been suggested to improve the production of the substance.[4]
The physiological properties have been discovered already by the chemists first synthesising the compound in 1928:
"Physiological Properties – Certain of these dinitriles have the effect of sneeze and tear gases. They are harmless when wet but to handle the dry powder is disastrous. (sic)"[3]
## Use as an aerosol
As 2-chlorobenzalmalononitrile is a solid at room temperature, not a gas, a variety of techniques have been used to make this solid usable as an aerosol:
- Melted and sprayed in the molten form.
- Dissolved in organic solvent.
- CS2 dry powder (CS2 is a siliconized, micro-pulverized form of CS).
- CS from thermal grenades by generation of hot gases.[5]
In the Waco Siege, CS was dissolved in the organic solvent dichloromethane (also known as methylene chloride). When the volatile dichlormethane evaporated, the CS crystallized with the dichloromethane molecules as an aerosol.[5] Another method typically used for grenades is to combine CS with a pyrotechnic composition which burns to generate an aerosol of CS-laden smoke. As the smoke disperses, tiny CS crystals 'ride' the smoke molecules to their targets, where they affect the eyes, nose, throat and skin causing extreme irritation.
# Effects
Many types of tear gas and other Riot Control Agents have been produced with effects ranging from mild tearing of the eyes to immediate vomiting and prostration. CN and CS are the most widely used and known, but around 15 different types of tear gas have been developed worldwide e.g. Adamsite or Bromoacetone, CNB, and CNC. CS has become the most popular due to its strong effect and lack of toxicity in comparison with other similar chemical agents. The effect of CS on a person will depend on whether it is packaged as a solution or used as an aerosol; the size of solution droplets and the size of the CS particulates after evaporation are factors determining its effect on the human body. Certain individuals, however, have been found to be particularly sensitive to CS and/or the organic solvents that are utilized. Studies on the use of CS on the public have noted that it may be ineffective against persons who are either mentally ill or who are under the effects of drugs and alcohol.[6]
Persons who have had contact with CS sometimes develop allergic contact dermatitis,[7] even with blisters and crust.[8][9]
Studies show that most of the effects are of a relative short term, but individuals notice some mild effects even after months.[10]
The chemical reacts with moisture on the skin and in the eyes causing a burning sensation and the immediate forceful and uncontrollable shutting of the eyes. Reported effects can include tears streaming from the eyes, running nose full of mucus, burning in the nose and throat areas, disorientation, dizziness and restricted breathing. In highly concentrated doses it can also induce severe coughing and vomiting. Almost all of the immediate effects wear off in a matter of minutes.
# Use
CS is used in spray form by many police forces as a temporary incapacitant and to subdue attackers or persons who are violently aggressive. Officers that are trained in the use and application of CS spray are routinely exposed to it as part of their training.
Recently, blank pistol cartridges carrying CS in powder form have been released to public. These, when fired in relatively close ranges, fully expose the target to the effects of CS, and are employed as a potent defensive weapon in regions where blank firing pistols are legally permitted for such use.
Although predominantly used by police it has also been used in criminal attacks in various countries.[11][12][13][14]
Use of CS in war is prohibited under the terms of the 1997 Chemical Weapons Convention (signed in 1993) because it could trigger retaliation with more toxic agents such as nerve gas. Domestic police use of CS, however, is legal in many countries.
## Cyprus
CS was first tested in the field by the British army in Cyprus in 1958. At this time it was known by the code name T792.[15]
## Vietnam
It has been reported that thousands of tons of CS gas were used by the U.S. forces in Vietnam to bring Viet Cong into the open, other estimates report 15 million pounds (7500 tons) of CS being used.[16] It was also used by the North Vietnamese forces in some battles like Hue in 1968 or during the Easter Offensive in 1972.[17]
## Northern Ireland
CS gas was used extensively in the Bogside area of Derry, Northern Ireland during the "Battle of the Bogside", a two-day riot in August, 1969. A total of 1,091 canisters containing 12.5g of CS each, and 14 canisters containing 50g of CS each, were released in the densely populated residential area.[18] On 30 August the Himsworth Inquiry was set up to investigate the medical effects of its use in Derry. Its conclusions, viewed in the political context of the time, still pointed towards the necessity of further testing of CS gas before being used as a riot control agent. During the rioting in Belfast, the following year, known as the Falls Curfew, the Army fired up to 1,600 canisters into the densely populated Falls Road area. Not long after, the British Army and RUC ceased using CS in Northern Ireland. Up to this point, it had been used in crowd control scenarios in Derry and Belfast.
## Iraq
Iraq successfully developed CS during the 1970s and during the 1980s produced tons of the substance firstly at Salman Pak and later at al-Muthanna.[19] Saddam Hussein used CS against the Kurds in his own country and against Iran during the Iran-Iraq War. Blackwater Worldwide, acting as an agent of the United States, deployed CS in the Iraq War from a helicopter hovering over a checkpoint in the Green Zone in Bagdhad.[20]
## Philippines
CS tear gas was used in submersion of the mutiny in Makati that was led by Sen. Antonio Trillanes. The tear gas was fired in the building and all the people in the building including reporters were affected.
## England, Scotland & Wales
CS tear gas was first used in mainland Britain to quell rioting in the Toxteth area of Liverpool in 1981.[21]
Personal incapacitant spray (PIS) was sanctioned for use by police in England and Wales in 1995.[22] The CS preparation in this case is CS dissolved in the organic solvent MiBK, or methyl iso-butyl ketone, an industrial de-greasing agent. The aerosol propellant used in this preparation is nitrogen.[23] Officers in Scotland carry CS spray on their belt.
It has been noted that the solvent MiBK is itself harmful, and can cause inflammation, dermatitis, burns to the skin and liver damage.[24]
A six month trial by 16 police forces in England began on the 1 March 1996. Only two weeks later, on 16 March 1996, a Gambian asylum seeker, Ibrahima Sey was taken to Ilford Police Station in East London. Whilst incapacitating the man, police sprayed him with CS and held him on the ground for over 15 minutes. The man died, the case was taken to court and although a verdict of "unlawful killing" was given by the jury at the end of the inquiry into his death, no charges were brought against any member of the police force.[25]
The forces that do use the PIS in the UK require that police constables should themselves be sprayed with a 3% dissolved CS, during self-defense training, in order for them to be able to be authorized to carry it as personal protection equipment. They are also trained in helping the incapacitated person recover quickly once successfully restrained. Most forces currently issue CS spray to its officers, but there has been a recent move for a few forces to issue PAVA Spray (pelargonic acid vanillylamide aka nonivamide).
The CS spray used by UK police has 5 times as much CS as the spray used by American police forces (5% dissolved CS and 1% CS respectively).[26]
In 1999 the UK mental health charity MIND called for a suspension in its use until it is fully tested and there is proof that CS is safe.[27]
More recently, in February 2006, there were calls to have CS spray banned in the UK after Dan Ford, from Wareham in Dorset, was permanently facially scarred after being sprayed in the face with a police CS canister. Mr Ford was subsequently advised by doctors to stay out of sunlight for at least 12 months. About the incident, his cousin, Donna Lewis, was quoted as saying, "To look at him, it was like looking at a melting man, with liquid oozing from his face."[28]
However, it is not yet confirmed that Mr Ford's injury is a reaction to having been exposed to police CS spray, or whether an unrelated chemical exposure has caused the injury. An investigation is ongoing.
The British Armed Forces use CS gas annually to test their CBRN equipment. During initial training they introduce recruits to CS gas by ordering them into a small enclosed space known as a Respirator Test Facility (RTF) and igniting chemical tablets to induce CS production. When recruits have carried out their CBRN drills (which include immediate actions for decontamination, an eating drill, a drinking drill and a gas mask canister change) the NCO in charge of the RTF will order them to remove their respirators and inhale the CS. This is apparently to inform the trainees of what CS effects feel like, so they can have trust in their equipment and procedures, thus proving to themselves that it works in the contaminated environment in training, and are then able to take this confidence to the battlefield environment.
In 2005, a student from Mayfield School in Essex, used CS Gas inside a school. Several students were taken to A&E, but all survived. The remaining students of the school were held in classrooms and halls, until it was confirmed by the local police and firefighters that the scene was safe. The event was reported only in a local newspaper, the Ilford Recorder.
## United States
CS is used by many police forces within the United States. It was most infamously used as one of a number of techniques by FBI law enforcement officials in the 1993 Waco Siege.[29]
Members of the US armed forces are exposed to CS during initial training, and during training refresher courses or equipment maintenance exercises, using CS tablets that are melted on a hotplate. This is to demonstrate the importance of properly wearing a gas mask or a Protective mask, as the agent's presence quickly reveals an improper fit or seal of the mask's rubber gaskets against the face. These exercises also encourage confidence in the ability of the equipment to protect the wearer from such chemical attacks. Basic Combat Trainees in the United States Army are always exposed in a gas-chamber environment using the tablet form, and often the Drill Sergeants put them in formation near the end of their 9 week cycle and throw CS grenades at them.
## Elsewhere
CS was used in large quantities to quell a protest in Lusaka, Zambia in July 1997 and the 1999 WTO protest in Seattle. Amnesty International reported that it had been manufactured by the UK company Pains-Wessex. Subsequently, Amnesty called for an export ban when the receiving regime is either not fully trained in the use of CS, or had shown usage "contrary to the manufacturer’s instructions".[30]
In September 2000, the Guardian Newspaper revealed how a UK company, HPP, used legal loopholes to export CS to a private security company in Rwanda, in breach of United Nations sanctions.[31] The Guardian also reported that CS was used by the Hutu militia in Rwanda to flush Tutsis out of buildings before hacking them to death.
CS has been used by the government in South Africa; by Israel against Palestinians and Israelis; by the South Korean government in Seoul, and during the Balkan conflicts by Serbia.
CS tear gas was used at the G8 protests in Genoa, Italy[32] and Quebec, Canada[33] during the FTAA anti-globalization demonstrations during the Quebec City Summit of the Americas.
The Canadian, Norwegian and Australian Armies train their soldiers with CS gas in a manner similar to that of the USA, as it is a basic part of NBC (nuclear, biological, chemical) or more recently within NATO, CBRN (Chemical, Biological, Radiological, Nuclear) training. Gas is released by burning tablets, usually in a tent or a small building reserved for this purpose (a "gas hut"), and soldiers are exposed to it on three occasions. During the first two exposures the soldier enters the tent or gas hut wearing a gas mask. During the first exposure he removes his gas mask and leaves the tent or hut. During the second exposure he must remove the mask, receive facial exposure, then replace and clear the mask. In the third exposure he enters the tent unprotected, must fit and clear the gas mask before leaving. Other drills such as drinking and under-mask decontamination are usually also practised yearly. Symptoms are a burning sensation on any moist skin, whether due to perspiration or other fluids such as tears or in the nasal membranes.
# Toxicity
Although described as a non-lethal weapon for crowd control, many studies have raised doubts about this classification. As well as creating severe pulmonary damage, CS can also significantly damage the heart and liver.[34]
On September 28, 2000, Prof. Dr. Uwe Heinrich released a study commissioned by John C. Danforth, of 'The Office of Special Counsel', to investigate the use of CS by the FBI at the Branch Davidians' Mount Carmel compound. He concluded that the lethality of CS used would have been determined mainly by two factors: whether gas masks were used and whether the occupants were trapped in a room. He suggests that if no gas masks were used and the occupants were trapped, then, "...there is a distinct possibility that this kind of CS exposure can significantly contribute to or even cause lethal effects."[5]
Many reports have associated CS exposure with miscarriages,[34] this is consistent with its reported clastogenic effect (abnormal chromosome change) on mammalian cells.
When CS is metabolized, cyanide can be detected in human tissue.[34] According to the United States Army Center for Health Promotion and Preventive Medicine, CS emits "very toxic fumes" when heated to decomposition, and at specified concentrations CS gas is an immediate danger to life and health. They also state that those exposed to CS gas should seek medical attention immediately.[35]
# Decontamination
CS contamination can be removed by washing with an alkaline solution of water and 5% sodium bisulfite.[2] A quick way to decontaminate the eyes is to pour cow's milk into them. Vision will be restored although breathing difficulties and pain will persist. | https://www.wikidoc.org/index.php/CS_gas | |
c8b673d9df86a9a4ea02b4955d061d1710cf728d | wikidoc | CTLA-4 | CTLA-4
CTLA4 or CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), also known as CD152 (cluster of differentiation 152), is a protein receptor that, functioning as an immune checkpoint, (or checkpoint inhibitor), downregulates immune responses. CTLA4 is constitutively expressed in regulatory T cells but only upregulated in conventional T cells after activation – a phenomenon which is particularly notable in cancers. It acts as an "off" switch when bound to CD80 or CD86 on the surface of antigen-presenting cells.
The CTLA-4 protein is encoded by the Ctla4 gene in mice and the CTLA4 gene in humans.
# History
In 1987, cytotoxic T-lymphocyte antigen 4, or CTLA-4, was identified by Pierre Golstein and colleagues . In November 1995, the labs of Tak Wah Mak and Arlene H. Sharpe independently published their findings on the discovery of the function of CTLA-4 as a negative regulator of T-cell activation, by knocking out the gene in mice. Previous studies from several labs had used methods which could not definitively define the function of CTLA-4, and were contradictory.
# Function
CTLA4 is a member of the immunoglobulin superfamily that is expressed by activated T cells and transmits an inhibitory signal to T cells. CTLA4 is homologous to the T-cell co-stimulatory protein, CD28, and both molecules bind to CD80 and CD86, also called B7-1 and B7-2 respectively, on antigen-presenting cells. CTLA-4 binds CD80 and CD86 with greater affinity and avidity than CD28 thus enabling it to outcompete CD28 for its ligands. CTLA4 transmits an inhibitory signal to T cells, whereas CD28 transmits a stimulatory signal. CTLA4 is also found in regulatory T cells (Tregs) and contributes to their inhibitory function. T cell activation through the T cell receptor and CD28 leads to increased expression of CTLA-4.
The mechanism by which CTLA-4 acts in T cells remains somewhat controversial. Biochemical evidence suggested that CTLA-4 recruits a phosphatase to the T cell receptor (TCR), thus attenuating the signal. This work remains unconfirmed in the literature since its first publication. More recent work has suggested that CTLA-4 may function in vivo by capturing and removing B7-1 and B7-2 from the membranes of antigen-presenting cells, thus making these unavailable for triggering of CD28.
In addition to that, it has been found that dendritic cell (DC) - Treg interaction causes sequestration of Fascin-1, an actin-bundling protein essential for immunological synapse formation and skews Fascin-1–dependent actin polarization in antigen presenting DCs toward the Treg cell adhesion zone. Although it is reversible upon T regulatory cell disengagement, this sequestration of essential cytoskeletal components causes a lethargic state of DCs, leading to reduced T cell priming. This suggests Treg-mediated immune suppression is a multi-step process. In addition to CTLA-4 CD80/CD86 interaction, fascin-dependent polarization of the cytoskeleton towards DC-Treg immune synapse may play a pivotal role.
CTLA-4 may also function via modulation of cell motility and/or signaling through PI3 kinase Early multiphoton microscopy studies observing T-cell motility in intact lymph nodes appeared to give evidence for the so-called ‘reverse-stop signaling model’. In this model CTLA-4 reverses the TCR-induced ‘stop signal’ needed for firm contact between T cells and antigen-presenting cells (APCs). However, those studies compared CTLA-4 positive cells, which are predominantly regulatory cells and are at least partially activated, with CTLA-4 negative naive T cells. The disparity of these cells in multiple regards may explain some of these results. Other groups who have analyzed the effect of antibodies to CTLA-4 in vivo have concluded little or no effect upon motility in the context of anergic T-cells. Antibodies to CTLA-4 may exert additional effects when used in vivo, by binding and thereby depleting regulatory T cells.
# Structure
The protein contains an extracellular V domain, a transmembrane domain, and a cytoplasmic tail. Alternate splice variants, encoding different isoforms, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. The intracellular domain is similar to that of CD28, in that it has no intrinsic catalytic activity and contains one YVKM motif able to bind PI3K, PP2A and SHP-2 and one proline-rich motif able to bind SH3 containing proteins. The first role of CTLA-4 in inhibiting T cell responses seem to be directly via SHP-2 and PP2A dephosphorylation of TCR-proximal signalling proteins such as CD3 and LAT. CTLA-4 can also affect signalling indirectly via competing with CD28 for CD80/86 binding. CTLA-4 can also bind PI3K, although the importance and results of this interaction are uncertain.
# Clinical significance
Variants in this gene have been associated with insulin-dependent diabetes mellitus, Graves' disease, Hashimoto's thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, primary biliary cirrhosis and other autoimmune diseases.
Polymorphisms of the CTLA-4 gene are associated with autoimmune diseases such as autoimmune thyroid disease and multiple sclerosis, though this association is often weak. In systemic lupus erythematosus (SLE), the splice variant sCTLA-4 is found to be aberrantly produced and found in the serum of patients with active SLE.
## Germline haploinsufficiency
Germline haploinsufficiency of CTLA4 leads to CTLA4 deficiency or CHAI disease (CTLA4 haploinsufficiency with autoimmune infiltration), a rare genetic disorder of the immune system. This may cause a dysregulation of the immune system and may result in lymphoproliferation, autoimmunity, hypogammaglobulinemia, recurrent infections, and may slightly increase one’s risk of lymphoma. CTLA4 mutations have first been described by a collaboration between the groups of Dr. Gulbu Uzel, Dr. Steven Holland, and Dr. Michael Lenardo from the National Institute of Allergy and Infectious Disease, Dr. Thomas Fleisher from the NIH Clinical Center at the National Institutes of Health, and their collaborators in 2014. In the same year a collaboration between the groups of Dr. Bodo Grimbacher, Dr. Shimon Sakaguchi, Dr. Lucy Walker and Dr. David Sansom and their collaborators described a similar phenotype.
CTLA4 mutations are inherited in an autosomal dominant manner. This means a person only needs one abnormal gene from one parent. The one normal copy is not enough to compensate for the one abnormal copy. Dominant inheritance means most families with CTLA4 mutations have affected relatives in each generation on the side of the family with the mutation.
### Clinical and laboratory manifestations
Symptomatic patients with CTLA4 mutations are characterized by an immune dysregulation syndrome including extensive T cell infiltration in a number of organs, including the gut, lungs, bone marrow, central nervous system, and kidneys. Most patients have diarrhea or enteropathy. Lymphadenopathy and hepatosplenomegaly are also common, as is autoimmunity. The organs affected by autoimmunity vary but include thrombocytopenia, hemolytic anemia, thyroiditis, type I diabetes, psoriasis, and arthritis. Respiratory infections are also common. Importantly, the clinical presentations and disease courses are variable with some individuals severely affected, whereas others show little manifestation of disease. This “variable expressivity,” even within the same family, can be striking and may be explained by differences in lifestyle, exposure to pathogens, treatment efficacy, or other genetic modifiers. This condition is described to have incomplete penetrance of disease. Penetrance is said to be incomplete when some individuals fail to express the trait and seem completely asymptomatic, even though they carry the allele. The penetrance is estimated to be about 60%.
The clinical symptoms are caused by abnormalities of the immune system. Most patients develop reduced levels of at least one immunoglobulin isotype, and have low CTLA4 protein expression in T regulatory cells, hyperactivation of effector T cells, low switched memory B cells, and progressive loss of circulating B cells.
### Treatment
Once a diagnosis is made, the treatment is based on an individual’s clinical condition and may include standard management for autoimmunity and immunoglobulin deficiencies. A recent study treated a Korean CHAI disease patient with CTLA4 mimetic, CTLA4-Ig (e.g.. abatacept) and was able to control immune activity and improve patient symptoms. Regular administration of abatacept improved the patient’s severe anemia and diarrhea (3L/day) and brought 3-year-long hospitalization to an end.
## Agonists to reduce immune activity
The comparatively higher binding affinity of CTLA4 has made it a potential therapy for autoimmune diseases. Fusion proteins of CTLA4 and antibodies (CTLA4-Ig) have been used in clinical trials for rheumatoid arthritis. The fusion protein CTLA4-Ig is commercially available as Orencia (abatacept). A second generation form of CTLA4-Ig known as belatacept was recently approved by the FDA based on favorable results from the randomized Phase III BENEFIT (Belatacept Evaluation of Nephroprotection and Efficacy as First Line Immunosuppression Trial) study. It was approved for renal transplantation in patients that are sensitized to Epstein–Barr virus (EBV).
## Antagonists to increase immune activity
Conversely, there is increasing interest in the possible therapeutic benefits of blocking CTLA4 (using antagonistic antibodies against CTLA such as ipilimumab (FDA approved for melanoma in 2011) as a means of inhibiting immune system tolerance to tumours and thereby providing a potentially useful immunotherapy strategy for patients with cancer. This is the first approved immune checkpoint blockade therapy. Another (not yet approved) is tremelimumab.
The 2018 Nobel Prize in Physiology or Medicine was awarded to James P. Allison and Tasuku Honjo "for their discovery of cancer therapy by inhibition of negative immune regulation".
# Interactions
CTLA-4 has been shown to interact with:
- AP2M1,
- CD80,
- CD86,
- SHP-2, and
- PPP2R5A. | CTLA-4
CTLA4 or CTLA-4 (cytotoxic T-lymphocyte-associated protein 4), also known as CD152 (cluster of differentiation 152), is a protein receptor that, functioning as an immune checkpoint, (or checkpoint inhibitor), downregulates immune responses. CTLA4 is constitutively expressed in regulatory T cells but only upregulated in conventional T cells after activation – a phenomenon which is particularly notable in cancers.[1] It acts as an "off" switch when bound to CD80 or CD86 on the surface of antigen-presenting cells.
The CTLA-4 protein is encoded by the Ctla4 gene in mice[2] and the CTLA4 gene in humans.[3]
# History
In 1987, cytotoxic T-lymphocyte antigen 4, or CTLA-4, was identified by Pierre Golstein and colleagues [2]. In November 1995, the labs of Tak Wah Mak and Arlene H. Sharpe independently published their findings on the discovery of the function of CTLA-4 as a negative regulator of T-cell activation, by knocking out the gene in mice.[4][5] Previous studies from several labs had used methods which could not definitively define the function of CTLA-4, and were contradictory.[6]
# Function
CTLA4 is a member of the immunoglobulin superfamily that is expressed by activated T cells and transmits an inhibitory signal to T cells. CTLA4 is homologous to the T-cell co-stimulatory protein, CD28, and both molecules bind to CD80 and CD86, also called B7-1 and B7-2 respectively, on antigen-presenting cells. CTLA-4 binds CD80 and CD86 with greater affinity and avidity than CD28 thus enabling it to outcompete CD28 for its ligands. CTLA4 transmits an inhibitory signal to T cells,[7][8][9][4] whereas CD28 transmits a stimulatory signal.[10][11] CTLA4 is also found in regulatory T cells (Tregs) and contributes to their inhibitory function. T cell activation through the T cell receptor and CD28 leads to increased expression of CTLA-4.
The mechanism by which CTLA-4 acts in T cells remains somewhat controversial. Biochemical evidence suggested that CTLA-4 recruits a phosphatase to the T cell receptor (TCR), thus attenuating the signal.[12] This work remains unconfirmed in the literature since its first publication. More recent work has suggested that CTLA-4 may function in vivo by capturing and removing B7-1 and B7-2 from the membranes of antigen-presenting cells, thus making these unavailable for triggering of CD28.[13]
In addition to that, it has been found that dendritic cell (DC) - Treg interaction causes sequestration of Fascin-1, an actin-bundling protein essential for immunological synapse formation and skews Fascin-1–dependent actin polarization in antigen presenting DCs toward the Treg cell adhesion zone. Although it is reversible upon T regulatory cell disengagement, this sequestration of essential cytoskeletal components causes a lethargic state of DCs, leading to reduced T cell priming. This suggests Treg-mediated immune suppression is a multi-step process. In addition to CTLA-4 CD80/CD86 interaction, fascin-dependent polarization of the cytoskeleton towards DC-Treg immune synapse may play a pivotal role.[14]
CTLA-4 may also function via modulation of cell motility and/or signaling through PI3 kinase[15] Early multiphoton microscopy studies observing T-cell motility in intact lymph nodes appeared to give evidence for the so-called ‘reverse-stop signaling model’.[16] In this model CTLA-4 reverses the TCR-induced ‘stop signal’ needed for firm contact between T cells and antigen-presenting cells (APCs).[17] However, those studies compared CTLA-4 positive cells, which are predominantly regulatory cells and are at least partially activated, with CTLA-4 negative naive T cells. The disparity of these cells in multiple regards may explain some of these results. Other groups who have analyzed the effect of antibodies to CTLA-4 in vivo have concluded little or no effect upon motility in the context of anergic T-cells.[18] Antibodies to CTLA-4 may exert additional effects when used in vivo, by binding and thereby depleting regulatory T cells.[19]
# Structure
The protein contains an extracellular V domain, a transmembrane domain, and a cytoplasmic tail. Alternate splice variants, encoding different isoforms, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. The intracellular domain is similar to that of CD28, in that it has no intrinsic catalytic activity and contains one YVKM motif able to bind PI3K, PP2A and SHP-2 and one proline-rich motif able to bind SH3 containing proteins. The first role of CTLA-4 in inhibiting T cell responses seem to be directly via SHP-2 and PP2A dephosphorylation of TCR-proximal signalling proteins such as CD3 and LAT. CTLA-4 can also affect signalling indirectly via competing with CD28 for CD80/86 binding. CTLA-4 can also bind PI3K, although the importance and results of this interaction are uncertain.
# Clinical significance
Variants in this gene have been associated with insulin-dependent diabetes mellitus, Graves' disease, Hashimoto's thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, primary biliary cirrhosis and other autoimmune diseases.
Polymorphisms of the CTLA-4 gene are associated with autoimmune diseases such as autoimmune thyroid disease and multiple sclerosis, though this association is often weak. In systemic lupus erythematosus (SLE), the splice variant sCTLA-4 is found to be aberrantly produced and found in the serum of patients with active SLE.
## Germline haploinsufficiency
Germline haploinsufficiency of CTLA4 leads to CTLA4 deficiency or CHAI disease (CTLA4 haploinsufficiency with autoimmune infiltration), a rare genetic disorder of the immune system. This may cause a dysregulation of the immune system and may result in lymphoproliferation, autoimmunity, hypogammaglobulinemia, recurrent infections, and may slightly increase one’s risk of lymphoma. CTLA4 mutations have first been described by a collaboration between the groups of Dr. Gulbu Uzel, Dr. Steven Holland, and Dr. Michael Lenardo from the National Institute of Allergy and Infectious Disease, Dr. Thomas Fleisher from the NIH Clinical Center at the National Institutes of Health, and their collaborators in 2014.[20] In the same year a collaboration between the groups of Dr. Bodo Grimbacher, Dr. Shimon Sakaguchi, Dr. Lucy Walker and Dr. David Sansom and their collaborators described a similar phenotype.[21]
CTLA4 mutations are inherited in an autosomal dominant manner. This means a person only needs one abnormal gene from one parent. The one normal copy is not enough to compensate for the one abnormal copy. Dominant inheritance means most families with CTLA4 mutations have affected relatives in each generation on the side of the family with the mutation.
### Clinical and laboratory manifestations
Symptomatic patients with CTLA4 mutations are characterized by an immune dysregulation syndrome including extensive T cell infiltration in a number of organs, including the gut, lungs, bone marrow, central nervous system, and kidneys. Most patients have diarrhea or enteropathy. Lymphadenopathy and hepatosplenomegaly are also common, as is autoimmunity. The organs affected by autoimmunity vary but include thrombocytopenia, hemolytic anemia, thyroiditis, type I diabetes, psoriasis, and arthritis. Respiratory infections are also common. Importantly, the clinical presentations and disease courses are variable with some individuals severely affected, whereas others show little manifestation of disease. This “variable expressivity,” even within the same family, can be striking and may be explained by differences in lifestyle, exposure to pathogens, treatment efficacy, or other genetic modifiers.[20][21][22][23] This condition is described to have incomplete penetrance of disease. Penetrance is said to be incomplete when some individuals fail to express the trait and seem completely asymptomatic, even though they carry the allele. The penetrance is estimated to be about 60%.
The clinical symptoms are caused by abnormalities of the immune system. Most patients develop reduced levels of at least one immunoglobulin isotype, and have low CTLA4 protein expression in T regulatory cells, hyperactivation of effector T cells, low switched memory B cells, and progressive loss of circulating B cells.[20][21][23]
### Treatment
Once a diagnosis is made, the treatment is based on an individual’s clinical condition and may include standard management for autoimmunity and immunoglobulin deficiencies. A recent study treated a Korean CHAI disease patient with CTLA4 mimetic, CTLA4-Ig (e.g.. abatacept) and was able to control immune activity and improve patient symptoms. Regular administration of abatacept improved the patient’s severe anemia and diarrhea (3L/day) and brought 3-year-long hospitalization to an end.[23]
## Agonists to reduce immune activity
The comparatively higher binding affinity of CTLA4 has made it a potential therapy for autoimmune diseases. Fusion proteins of CTLA4 and antibodies (CTLA4-Ig) have been used in clinical trials for rheumatoid arthritis.[24] The fusion protein CTLA4-Ig is commercially available as Orencia (abatacept). A second generation form of CTLA4-Ig known as belatacept was recently approved by the FDA based on favorable results from the randomized Phase III BENEFIT (Belatacept Evaluation of Nephroprotection and Efficacy as First Line Immunosuppression Trial) study. It was approved for renal transplantation in patients that are sensitized to Epstein–Barr virus (EBV).
## Antagonists to increase immune activity
Conversely, there is increasing interest in the possible therapeutic benefits of blocking CTLA4 (using antagonistic antibodies against CTLA such as ipilimumab (FDA approved for melanoma in 2011) as a means of inhibiting immune system tolerance to tumours and thereby providing a potentially useful immunotherapy strategy for patients with cancer.[1] This is the first approved immune checkpoint blockade therapy.[25] Another (not yet approved) is tremelimumab.[1]
The 2018 Nobel Prize in Physiology or Medicine was awarded to James P. Allison and Tasuku Honjo "for their discovery of cancer therapy by inhibition of negative immune regulation".
# Interactions
CTLA-4 has been shown to interact with:
- AP2M1,[26][27]
- CD80,[28][29]
- CD86,
- SHP-2, and
- PPP2R5A.[30] | https://www.wikidoc.org/index.php/CTLA-4 | |
1f0e82b9ac623699892f0edb1c260d2135e36dbd | wikidoc | CUGBP1 | CUGBP1
CUG triplet repeat, RNA binding protein 1, also known as CUGBP1, is a protein which in humans is encoded by the CUGBP1 gene.
# Function
Members of the CELF/BRUNOL protein family contain two N-terminal RNA recognition motif (RRM) domains, one C-terminal RRM domain, and a divergent segment of 160-230 aa between the second and third RRM domains. Members of this protein family regulate pre-mRNA alternative splicing and may also be involved in mRNA editing, and translation. This gene may play a role in myotonic dystrophy type 1 (DM1) via interactions with the dystrophia myotonica-protein kinase (DMPK) gene. Alternative splicing results in multiple transcript variants encoding different isoforms.
# mRNA degradation factor
It is estimated that 5 to 8% of human mRNAs are unstable because of mRNA instability elements in their 3' untranslated regions (3'UTR). A number of such elements have been called AU-rich elements (AREs). It is now known that AREs are binding sites for RNA-binding proteins that target mRNAs to rapid degradation. However, only few of the proteins reported to bind AREs were demonstrated to play a role in mRNA degradation. A shared feature of these proteins is to bind only to a subclass of the known AREs that contain the pentamer AUUUA. A convergent effort of several research teams now adds CUGBP1 (CUG binding protein 1) to the short list of ARE-Binding proteins that control mRNA stability, with the peculiarity that it binds to non-AUUUA AREs. CUGBP1 has been involved both as a key regulator of human myotonic dystrophy 1 (DM1) and more recently as a regulator of human papilloma virus mRNA expression.
Evidence for CUGBP1 acting as a RNA degradation factor came first from the Xenopus model. Xenopus CUGBP1 (xCUGBP1, formerly known as EDEN-BP) was identified in 1998 for its ability to bind specifically to a GU-rich element (Embryonic deadenylation element EDEN) located in the 3'UTRs of some mRNAs that are rapidly deadenylated and translationally repressed after fertilization in early development. Because deadenylation is often the rate limiting step of mRNA degradation the enhancement of deadenylation increases mRNA turnover.
Human CUGBP1 (hCUGBP1) had been previously identified by Timchenko and colleagues for its ability to bind to CUG repeats located in the DMPK 3'UTR. A large amount of work has since described the role of hCUGBP1 on control of alternative splicing and will not be discussed here. The demonstration that hCUGBP1 is involved in the control of mRNA deadenylation and instability like xCUGBP1 came next. In mammalian cell extract as well as in xenopus egg extracts, depletion and rescue experiments showed that specific binding of CUGBP1 to the 3'UTR of mRNA is required for the targeted specific deadenylation to occur. In rescue experiments in xenopus egg extracts, the recombinant human protein can replace the xenopus one making them functional homolog. Furthermore, the Poly(A) ribonuclease PARN was shown to interact with CUGBP1. In human cells, tethering of hCUGBP1 to a mRNA decreases its steadystate suggesting the destabilization of the mRNA. The first human mRNA reported to be targeted to rapid deadenylation and degradation by CUGBP1 is the oncogene c-jun. Years ago, it was shown that the class III ARE (devoid of any AUUUA motif) of the human c-jun oncogene directed rapid deadenylation and degradation to a reporter mRNA. Both xCUGBP1 and hCUGBP1 were shown to specifically bind to c-jun ARE. The binding of CUGBP1 to the 3'UTR of mRNAs bearing GU-rich element would target these mRNAs for rapid deadenylation by PARN and subsequent degradation. This was recently demonstrated by siRNA-mediated knockdown of hCUGBP1 that led to stabilization of a reporter RNA bearing the c-jun UG -rich ARE.
UGU(G/A) tetranucleotides are key determinants of the binding site for xCUGBP1. A SELEX approach for the identification of artificial substrate of hCUGBP1 led to the proposition that UGU containing sequences were highly favoured for binding. More recently, the reappraisal of CUGBP1 binding sites on the base of a combination of the SELEX approach and
Immunoprecipitation of the CUGBP1 containing complexes has led Graindorge et al. to propose a 15 nt motif as a key determinant of CUGBP1 binding. Such a motif is found in a number of unstable mRNAs in human cells suggesting that they are degraded by a CUGBP1 deadenylation dependant pathway. | CUGBP1
CUG triplet repeat, RNA binding protein 1, also known as CUGBP1, is a protein which in humans is encoded by the CUGBP1 gene.[1][2][3]
# Function
Members of the CELF/BRUNOL protein family contain two N-terminal RNA recognition motif (RRM) domains, one C-terminal RRM domain, and a divergent segment of 160-230 aa between the second and third RRM domains. Members of this protein family regulate pre-mRNA alternative splicing and may also be involved in mRNA editing, and translation. This gene may play a role in myotonic dystrophy type 1 (DM1) via interactions with the dystrophia myotonica-protein kinase (DMPK) gene. Alternative splicing results in multiple transcript variants encoding different isoforms.[1]
# mRNA degradation factor
It is estimated that 5 to 8% of human mRNAs are unstable because of mRNA instability elements in their 3' untranslated regions (3'UTR).[4] A number of such elements have been called AU-rich elements (AREs). It is now known that AREs are binding sites for RNA-binding proteins that target mRNAs to rapid degradation. However, only few of the proteins reported to bind AREs were demonstrated to play a role in mRNA degradation. A shared feature of these proteins is to bind only to a subclass of the known AREs that contain the pentamer AUUUA. A convergent effort of several research teams now adds CUGBP1 (CUG binding protein 1) to the short list of ARE-Binding proteins that control mRNA stability, with the peculiarity that it binds to non-AUUUA AREs. CUGBP1 has been involved both as a key regulator of human myotonic dystrophy 1 (DM1) and more recently as a regulator of human papilloma virus mRNA expression.[5]
Evidence for CUGBP1 acting as a RNA degradation factor came first from the Xenopus model. Xenopus CUGBP1 (xCUGBP1, formerly known as EDEN-BP) was identified in 1998[6] for its ability to bind specifically to a GU-rich element (Embryonic deadenylation element EDEN) located in the 3'UTRs of some mRNAs that are rapidly deadenylated and translationally repressed after fertilization in early development. Because deadenylation is often the rate limiting step of mRNA degradation the enhancement of deadenylation increases mRNA turnover.[7]
Human CUGBP1 (hCUGBP1) had been previously identified by Timchenko and colleagues[2] for its ability to bind to CUG repeats located in the DMPK 3'UTR. A large amount of work has since described the role of hCUGBP1 on control of alternative splicing and will not be discussed here.[8] The demonstration that hCUGBP1 is involved in the control of mRNA deadenylation and instability like xCUGBP1 came next. In mammalian cell extract as well as in xenopus egg extracts, depletion and rescue experiments showed that specific binding of CUGBP1 to the 3'UTR of mRNA is required for the targeted specific deadenylation to occur.[9] In rescue experiments in xenopus egg extracts, the recombinant human protein can replace the xenopus one making them functional homolog.[10] Furthermore, the Poly(A) ribonuclease PARN was shown to interact with CUGBP1.[11] In human cells, tethering of hCUGBP1 to a mRNA decreases its steadystate suggesting the destabilization of the mRNA.[12] The first human mRNA reported to be targeted to rapid deadenylation and degradation by CUGBP1 is the oncogene c-jun. Years ago, it was shown that the class III ARE (devoid of any AUUUA motif) of the human c-jun oncogene directed rapid deadenylation and degradation to a reporter mRNA.[13] Both xCUGBP1 and hCUGBP1 were shown to specifically bind to c-jun ARE.[9] The binding of CUGBP1 to the 3'UTR of mRNAs bearing GU-rich element would target these mRNAs for rapid deadenylation by PARN and subsequent degradation. This was recently demonstrated by siRNA-mediated knockdown of hCUGBP1 that led to stabilization of a reporter RNA bearing the c-jun UG -rich ARE.[14]
UGU(G/A) tetranucleotides are key determinants of the binding site for xCUGBP1. A SELEX approach for the identification of artificial substrate of hCUGBP1 led to the proposition that UGU containing sequences were highly favoured for binding.[15] More recently, the reappraisal of CUGBP1 binding sites on the base of a combination of the SELEX approach and
Immunoprecipitation of the CUGBP1 containing complexes has led Graindorge et al. to propose a 15 nt motif as a key determinant of CUGBP1 binding.[16] Such a motif is found in a number of unstable mRNAs in human cells[14] suggesting that they are degraded by a CUGBP1 deadenylation dependant pathway. | https://www.wikidoc.org/index.php/CUGBP1 | |
f9bd090f7ad5f1c25409bf4e1c91288755bade44 | wikidoc | CX3CL1 | CX3CL1
Fractalkine also known as chemokine (C-X3-C motif) ligand 1 is a protein that in humans is encoded by the CX3CL1 gene.
# Function
Fractalkine is a large cytokine protein of 373 amino acids, it contains multiple domains and is the only known member of the CX3C chemokine family. It is also commonly known under the names fractalkine (in humans) and neurotactin (in mice). The polypeptide structure of CX3CL1 differs from the typical structure of other chemokines. For example, the spacing of the characteristic N-terminal cysteines differs; there are three amino acids separating the initial pair of cysteines in CX3CL1, with none in CC chemokines and only one intervening amino acid in CXC chemokines. CX3CL1 is produced as a long protein (with 373-amino acid in humans) with an extended mucin-like stalk and a chemokine domain on top. The mucin-like stalk permits it to bind to the surface of certain cells. However a soluble (90 kD) version of this chemokine has also been observed. Soluble CX3CL1 potently chemoattracts T cells and monocytes, while the cell-bound chemokine promotes strong adhesion of leukocytes to activated endothelial cells, where it is primarily expressed. CX3CL1 elicits its adhesive and migratory functions by interacting with the chemokine receptor CX3CR1. Its gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.
Fractalkine is found commonly throughout the brain, particularly in neural cells, and its receptor is known to be present on microglial cells. It has also been found to be essential for microglial cell migration. CX3CL1 is also up-regulated in the hippocampus during a brief temporal window following spatial learning, the purpose of which may be to regulate glutamate-mediated neurotransmission tone. This indicates a possible role for the chemokine in the protective plasticity process of synaptic scaling. | CX3CL1
Fractalkine also known as chemokine (C-X3-C motif) ligand 1 is a protein that in humans is encoded by the CX3CL1 gene.
# Function
Fractalkine is a large cytokine protein of 373 amino acids, it contains multiple domains and is the only known member of the CX3C chemokine family. It is also commonly known under the names fractalkine (in humans) and neurotactin (in mice).[1][2] The polypeptide structure of CX3CL1 differs from the typical structure of other chemokines. For example, the spacing of the characteristic N-terminal cysteines differs; there are three amino acids separating the initial pair of cysteines in CX3CL1, with none in CC chemokines and only one intervening amino acid in CXC chemokines. CX3CL1 is produced as a long protein (with 373-amino acid in humans) with an extended mucin-like stalk and a chemokine domain on top. The mucin-like stalk permits it to bind to the surface of certain cells. However a soluble (90 kD) version of this chemokine has also been observed. Soluble CX3CL1 potently chemoattracts T cells and monocytes, while the cell-bound chemokine promotes strong adhesion of leukocytes to activated endothelial cells, where it is primarily expressed.[2] CX3CL1 elicits its adhesive and migratory functions by interacting with the chemokine receptor CX3CR1.[3] Its gene is located on human chromosome 16 along with some CC chemokines known as CCL17 and CCL22.[2][4]
Fractalkine is found commonly throughout the brain, particularly in neural cells, and its receptor is known to be present on microglial cells. It has also been found to be essential for microglial cell migration.[5] CX3CL1 is also up-regulated in the hippocampus during a brief temporal window following spatial learning, the purpose of which may be to regulate glutamate-mediated neurotransmission tone. This indicates a possible role for the chemokine in the protective plasticity process of synaptic scaling.[6] | https://www.wikidoc.org/index.php/CX3CL1 | |
165dcc6fc7025e60682e15c059f01dd338337897 | wikidoc | CX3CR1 | CX3CR1
CX3C chemokine receptor 1 (CX3CR1) also known as the fractalkine receptor or G-protein coupled receptor 13 (GPR13) is a protein that in humans is encoded by the CX3CR1 gene. As the name suggests, this receptor binds the chemokine CX3CL1 (also called neurotactin or fractalkine).
# Function
The fractalkine ligand CX3CL1 is a transmembrane protein and chemokine involved in the adhesion and migration of leukocytes. The protein encoded by the CX3CR1 gene is a receptor for the fractalkine ligand.
Expression of this receptor appears to be associated with lymphocytes. CX3CR1 is also expressed by monocytes and plays a major role in the survival of monocytes.
Fractalkine signaling has also recently been discovered to play a developmental role in the migration of microglia in the central nervous system to their synaptic targets, where phagocytosis and synaptic refinement occur. CX3CR1 knockout mice had more synapses on cortical neurons than wild-type mice.
# Clinical significance
CX3CR1 also is a coreceptor for HIV-1, and some variations in this gene lead to increased susceptibility to HIV-1 infection and rapid progression to AIDS.
CX3CR1 variants have been described to modify the survival time and the progression rate of patients with amyotrophic lateral sclerosis.
Mutations in CX3CR1 are associated to dysplasia of the hip . | CX3CR1
CX3C chemokine receptor 1 (CX3CR1) also known as the fractalkine receptor or G-protein coupled receptor 13 (GPR13) is a protein that in humans is encoded by the CX3CR1 gene.[1][2] As the name suggests, this receptor binds the chemokine CX3CL1 (also called neurotactin or fractalkine).
# Function
The fractalkine ligand CX3CL1 is a transmembrane protein and chemokine involved in the adhesion and migration of leukocytes. The protein encoded by the CX3CR1 gene is a receptor for the fractalkine ligand.[3]
Expression of this receptor appears to be associated with lymphocytes.[4] CX3CR1 is also expressed by monocytes and plays a major role in the survival of monocytes.[5]
Fractalkine signaling has also recently been discovered to play a developmental role in the migration of microglia in the central nervous system to their synaptic targets, where phagocytosis and synaptic refinement occur. CX3CR1 knockout mice had more synapses on cortical neurons than wild-type mice.[6]
# Clinical significance
CX3CR1 also is a coreceptor for HIV-1, and some variations in this gene lead to increased susceptibility to HIV-1 infection and rapid progression to AIDS.[3]
CX3CR1 variants have been described to modify the survival time and the progression rate of patients with amyotrophic lateral sclerosis.[7]
Mutations in CX3CR1 are associated to dysplasia of the hip .[8] | https://www.wikidoc.org/index.php/CX3CR1 | |
84ff9560f73b56e477c1dcd3b69eb40348f90c8b | wikidoc | CXCL10 | CXCL10
C-X-C motif chemokine 10 (CXCL10) also known as Interferon gamma-induced protein 10 (IP-10) or small-inducible cytokine B10 is an 8.7 kDa protein that in humans is encoded by the CXCL10 gene. C-X-C motif chemokine 10 is a small cytokine belonging to the CXC chemokine family.
# Gene
The gene for CXCL10 is located on human chromosome 4 in a cluster among several other CXC chemokines.
# Function
CXCL10 is secreted by several cell types in response to IFN-γ. These cell types include monocytes, endothelial cells and fibroblasts. CXCL10 has been attributed to several roles, such as chemoattraction for monocytes/macrophages, T cells, NK cells, and dendritic cells, promotion of T cell adhesion to endothelial cells, antitumor activity, and inhibition of bone marrow colony formation and angiogenesis.
This chemokine elicits its effects by binding to the cell surface chemokine receptor CXCR3.
# Structure
The three-dimensional crystal structure of this chemokine has been determined under 3 different conditions to a resolution of up to 1.92 Å. The Protein Data Bank accession codes for the structures of CXCL10 are 1lv9, 1o7y, and 1o80.
# Biomarkers
CXCL9, CXCL10 and CXCL11 have proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodeling.
# Clinical significance
Baseline pre-treatment plasma levels of CXCL10 are elevated in patients chronically infected with hepatitis C virus (HCV) of genotypes 1 or 4 who do not achieve a sustained viral response (SVR) after completion of antiviral therapy. CXCL10 in plasma is mirrored by intrahepatic CXCL10 mRNA, and both strikingly predict the first days of elimination of HCV RNA (“first phase decline”) during interferon/ribavirin therapy for all HCV genotypes. This also applies for patients co-infected with HIV, where pre-treatment IP-10 levels below 150 pg/mL are predictive of a favorable response, and may thus be useful in encouraging these otherwise difficult-to-treat patients to initiate therapy. | CXCL10
C-X-C motif chemokine 10 (CXCL10) also known as Interferon gamma-induced protein 10 (IP-10) or small-inducible cytokine B10 is an 8.7 kDa protein that in humans is encoded by the CXCL10 gene.[1][2] C-X-C motif chemokine 10 is a small cytokine belonging to the CXC chemokine family.
# Gene
The gene for CXCL10 is located on human chromosome 4 in a cluster among several other CXC chemokines.[3]
# Function
CXCL10 is secreted by several cell types in response to IFN-γ. These cell types include monocytes, endothelial cells and fibroblasts.[1] CXCL10 has been attributed to several roles, such as chemoattraction for monocytes/macrophages, T cells, NK cells, and dendritic cells, promotion of T cell adhesion to endothelial cells, antitumor activity, and inhibition of bone marrow colony formation and angiogenesis.[4][5]
This chemokine elicits its effects by binding to the cell surface chemokine receptor CXCR3.[6]
# Structure
The three-dimensional crystal structure of this chemokine has been determined under 3 different conditions to a resolution of up to 1.92 Å.[7] The Protein Data Bank accession codes for the structures of CXCL10 are 1lv9, 1o7y, and 1o80.
# Biomarkers
CXCL9, CXCL10 and CXCL11 have proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodeling.[8]
[9]
# Clinical significance
Baseline pre-treatment plasma levels of CXCL10 are elevated in patients chronically infected with hepatitis C virus (HCV) of genotypes 1 or 4 who do not achieve a sustained viral response (SVR) after completion of antiviral therapy.[10][11] CXCL10 in plasma is mirrored by intrahepatic CXCL10 mRNA, and both strikingly predict the first days of elimination of HCV RNA (“first phase decline”) during interferon/ribavirin therapy for all HCV genotypes.[12] This also applies for patients co-infected with HIV, where pre-treatment IP-10 levels below 150 pg/mL are predictive of a favorable response, and may thus be useful in encouraging these otherwise difficult-to-treat patients to initiate therapy.[13] | https://www.wikidoc.org/index.php/CXCL10 | |
5a6e0f78f7b787edf857c41e979a45f8b0d703f3 | wikidoc | CXCL11 | CXCL11
C-X-C motif chemokine 11 (CXCL11) is a protein that in humans is encoded by the CXCL11 gene.
C-X-C motif chemokine 11 is a small cytokine belonging to the CXC chemokine family that is also called Interferon-inducible T-cell alpha chemoattractant (I-TAC) and Interferon-gamma-inducible protein 9 (IP-9). It is highly expressed in peripheral blood leukocytes, pancreas and liver, with moderate levels in thymus, spleen and lung and low expression levels were in small intestine, placenta and prostate.
Gene expression of CXCL11 is strongly induced by IFN-γ and IFN-β, and weakly induced by IFN-α. This chemokine elicits its effects on its target cells by interacting with the cell surface chemokine receptor CXCR3, with a higher affinity than do the other ligands for this receptor, CXCL9 and CXCL10. CXCL11 is chemotactic for activated T cells. Its gene is located on human chromosome 4 along with many other members of the CXC chemokine family.
# Biomarkers
CXCL9, -10, -11 have proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodeling. | CXCL11
C-X-C motif chemokine 11 (CXCL11) is a protein that in humans is encoded by the CXCL11 gene.[1]
C-X-C motif chemokine 11 is a small cytokine belonging to the CXC chemokine family that is also called Interferon-inducible T-cell alpha chemoattractant (I-TAC) and Interferon-gamma-inducible protein 9 (IP-9). It is highly expressed in peripheral blood leukocytes, pancreas and liver, with moderate levels in thymus, spleen and lung and low expression levels were in small intestine, placenta and prostate.[2]
Gene expression of CXCL11 is strongly induced by IFN-γ and IFN-β, and weakly induced by IFN-α.[3] This chemokine elicits its effects on its target cells by interacting with the cell surface chemokine receptor CXCR3, with a higher affinity than do the other ligands for this receptor, CXCL9 and CXCL10.[2][4] CXCL11 is chemotactic for activated T cells. Its gene is located on human chromosome 4 along with many other members of the CXC chemokine family.[5][6]
# Biomarkers
CXCL9, -10, -11 have proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodeling.[7][8] | https://www.wikidoc.org/index.php/CXCL11 | |
2800c34438b00b86867047253b7ed775d476fb36 | wikidoc | CXCL13 | CXCL13
chemokine (C-X-C motif) ligand 13 (CXCL13), also known as B lymphocyte chemoattractant (BLC) or B cell-attracting chemokine 1 (BCA-1), is a protein ligand that in humans is encoded by the CXCL13 gene.
# Function
CXCL13 is a small chemokine belonging to the CXC chemokine family. As its name suggests, this chemokine is selectively chemotactic for B cells belonging to both the B-1 and B-2 subsets, and elicits its effects by interacting with chemokine receptor CXCR5. CXCL13 and its receptor CXCR5 control the organization of B cells within follicles of lymphoid tissues. and is expressed highly in the liver, spleen, lymph nodes, and gut of humans. The gene for CXCL13 is located on human chromosome 4 in a cluster of other CXC chemokines.
In T lymphocytes, CXCL13 expression is thought to reflect a germinal center origin of the T cell, particularly a subset of T cells called follicular B helper T cells (or TFH cells). Hence, expression of CXCL13 in T-cell lymphomas, such as Angioimmunoblastic T-cell Lymphoma, is thought to reflect a germinal center origin of the neoplastic T-cells. | CXCL13
chemokine (C-X-C motif) ligand 13 (CXCL13), also known as B lymphocyte chemoattractant (BLC) or B cell-attracting chemokine 1 (BCA-1), is a protein ligand that in humans is encoded by the CXCL13 gene.[1][2]
# Function
CXCL13 is a small chemokine belonging to the CXC chemokine family. As its name suggests, this chemokine is selectively chemotactic for B cells belonging to both the B-1 and B-2 subsets, and elicits its effects by interacting with chemokine receptor CXCR5.[1][3] CXCL13 and its receptor CXCR5 control the organization of B cells within follicles of lymphoid tissues.[4] and is expressed highly in the liver, spleen, lymph nodes, and gut of humans.[1] The gene for CXCL13 is located on human chromosome 4 in a cluster of other CXC chemokines.[2]
In T lymphocytes, CXCL13 expression is thought to reflect a germinal center origin of the T cell, particularly a subset of T cells called follicular B helper T cells (or TFH cells). Hence, expression of CXCL13 in T-cell lymphomas, such as Angioimmunoblastic T-cell Lymphoma, is thought to reflect a germinal center origin of the neoplastic T-cells.[5] | https://www.wikidoc.org/index.php/CXCL13 | |
df34ff27ca9f72d9c38db366aef5ec601a712810 | wikidoc | CXCL17 | CXCL17
Chemokine (C-X-C motif) ligand 17 (CXCL17) is a small cytokine belonging to the CXC chemokine family that has been identified in humans and mice. CXCL17 attracts dendritic cells and monocytes and is regulated in tumors. It is also known as VEGF co-regulated chemokine 1 (VCC-1) and dendritic cell- and monocyte-attracting chemokine-like protein (DMC). This chemokine is constitutively expressed in the lung. The gene for human CXCL17 is located on chromosome 19.
CXCL17 is an orphan chemokine with no known receptor.
# Receptor
The receptor for CXCL17 is likely to be a G protein-coupled receptor (GPCR).
The GPCR GPR35 was thought to be a receptor of CXCL17. Subsequent research has suggested that GPR35 is not a receptor for CXCL17. | CXCL17
Chemokine (C-X-C motif) ligand 17 (CXCL17) is a small cytokine belonging to the CXC chemokine family that has been identified in humans and mice. CXCL17 attracts dendritic cells and monocytes and is regulated in tumors. It is also known as VEGF co-regulated chemokine 1 (VCC-1) and dendritic cell- and monocyte-attracting chemokine-like protein (DMC).[1][2] This chemokine is constitutively expressed in the lung.[2] The gene for human CXCL17 is located on chromosome 19.[2]
CXCL17 is an orphan chemokine with no known receptor[3].
# Receptor
The receptor for CXCL17 is likely to be a G protein-coupled receptor (GPCR)[4].
The GPCR GPR35 was thought to be a receptor of CXCL17.[5] Subsequent research has suggested that GPR35 is not a receptor for CXCL17[3][6]. | https://www.wikidoc.org/index.php/CXCL17 | |
084e7feea02e34e290226dc6b5ccfef3d9ed8144 | wikidoc | CYB561 | CYB561
Cytochrome b561 is a protein that in humans is encoded by the CYB561 gene.
# Model organisms
Model organisms have been used in the study of CYB561 function. A conditional knockout mouse line, called Cyb561tm1a(EUCOMM)Wtsi was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Twenty three tests were carried out on mutant mice and one significant abnormality was observed: female homozygotes displayed a decreased circulating glucose level after a glucose tolerance test. | CYB561
Cytochrome b561 is a protein that in humans is encoded by the CYB561 gene.[1][2]
# Model organisms
Model organisms have been used in the study of CYB561 function. A conditional knockout mouse line, called Cyb561tm1a(EUCOMM)Wtsi[9][10] was generated as part of the International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.[11][12][13]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[7][14] Twenty three tests were carried out on mutant mice and one significant abnormality was observed: female homozygotes displayed a decreased circulating glucose level after a glucose tolerance test.[7] | https://www.wikidoc.org/index.php/CYB561 | |
f1e28bacc4f5e486fdbfa39888fddd852a27d472 | wikidoc | CYB5R3 | CYB5R3
NADH-cytochrome b5 reductase 3 is an enzyme that in humans is encoded by the CYB5R3 gene.
# Structure
The CYB5R3 gene is located on the 22nd chromosome, with its specific location being 22q13.2. The gene contains 12 exons. CYB5R3 encodes a 34.2 kDa protein that is composed of 301 amino acids; 63 peptides have been observed through mass spectrometry data.
The entire gene is about 31 kb in length. Exon 2 contains the junction of the membrane-binding domain and the catalytic domain of b5R, which shows that there are two forms of b5R: a soluble form and a membrane-bound form. The 5' portion of this gene does not have typical regulatory transcriptional elements, but has the sequence G-G-G-C-G-G a total of five times. The GC content of this 5' portion of the gene is 86%, much higher than the average GC of the entire gene, which is 55%. There is also an atypical polyadenylation signal in the 3'-untranslated region of the gene.
The protein encoded by the CYB5R3 gene is cytochrome b5 reductase, a flavoprotein that is produced as two different isoforms with different localizations. There is an amphipathic microsomal isoform that is found in all cell types but red blood cells; this isoform has one hydrophobic membrane-anchoring domain and one catalytic domain that is hydrophilic. The other isoform, a soluble cytochrome b5 reductase isoform, is found in human erythrocytes. This protein is truncated, and encoded by an alternative transcript that produces only the larger, hydrophilic domain. The protein contains 4 cyteine residues, Cys-203, -273, -283, and -297. Cys-283 is thought to be involved in NADH binding by chemical modification; in fact, both Cys-273 and Cys-283 are thought to be close to the NADH-binding site. The NH2-terminal structure of the membrane-binding domain is CH3(CH2)12-CO-Gly-Ala-Gln-Leu-Ser-Thr-Leu-Gly-His-Met-Val-Leu-Phe-Pro-Val-Trp-Phe-Leu-Tyr-Ser-Leu-Leu-Met-Lys.
Two forms of NADH-cytochrome b5 reductase are known, a membrane-bound form in somatic cells (anchored in the endoplasmic reticulum, mitochondria and other membranes) and a soluble form in erythrocytes. The membrane-bound form has both membrane-binding and catalytic domains. The soluble form has only the catalytic domain. This gene encodes both forms of the enzyme which arise from tissue-specific alternative transcripts that differ in the first exon. Mutations in this gene cause methemoglobinemias.
# Function
Cytochrome b5 reductase is involved in the transfer of reducing equivalents from the physiological electron donor, NADH, via an FAD domain to the small molecules of cytochrome b5. It’s also heavily involved in many oxidation and reduction reactions, such as the reduction of methemoglobin to hemoglobin. Of the two forms of NADH-cytochrome b5 reductase, the membrane-bound form exists mainly on the cytoplasmic side of the endoplasmic reticulum and functions in desaturation and elongation of fatty acids, in cholesterol biosynthesis, and in drug metabolism. The erythrocyte form is located in a soluble fraction of circulating erythrocytes and is involved in methemoglobin reduction.
# Clinical significance
Mutations in the CYB5R3 gene cause methemoglobinemia types I and II. This is a rare autosomal recessive disease due to a deficiency of isoform of NADH-cytochrome b5 reductase. Many mutations of this gene and the subsequent disease manifestation have been described. The disease manifests as the accumulation of oxidized Fe+3 in humans. Type I recessive congenital methemoglobinemia (RCM) is characterized by a deficiency of the soluble isoform and manifests as the cyanosis of skin and mucous membranes. In type II, the defect affects both isoforms and thus affects more general tissues such as red blood cells, leukocytes, and all body tissues. This type is associated with mental deficiency and other neurologic symptoms, which may be because the cytochrome b5 system plays a crucial role in the desaturation of fatty acids in the body. One patient was described as having a new class of this disorder, type III. This condition was characterized by a deficiency of NADH cytochrome b5 reductase in lymphocytes, platelets, and erythrocytes, but this was not associated with mental retardation.
# Interactions
CYB5R3 is known to interact with CYB5A, ENO1, and SUMO2 among other proteins. | CYB5R3
NADH-cytochrome b5 reductase 3 is an enzyme that in humans is encoded by the CYB5R3 gene.[1][2]
# Structure
The CYB5R3 gene is located on the 22nd chromosome, with its specific location being 22q13.2. The gene contains 12 exons.[3] CYB5R3 encodes a 34.2 kDa protein that is composed of 301 amino acids; 63 peptides have been observed through mass spectrometry data.[4][5]
The entire gene is about 31 kb in length. Exon 2 contains the junction of the membrane-binding domain and the catalytic domain of b5R, which shows that there are two forms of b5R: a soluble form and a membrane-bound form. The 5' portion of this gene does not have typical regulatory transcriptional elements, but has the sequence G-G-G-C-G-G a total of five times. The GC content of this 5' portion of the gene is 86%, much higher than the average GC of the entire gene, which is 55%. There is also an atypical polyadenylation signal in the 3'-untranslated region of the gene.[1]
The protein encoded by the CYB5R3 gene is cytochrome b5 reductase, a flavoprotein that is produced as two different isoforms with different localizations. There is an amphipathic microsomal isoform that is found in all cell types but red blood cells; this isoform has one hydrophobic membrane-anchoring domain and one catalytic domain that is hydrophilic. The other isoform, a soluble cytochrome b5 reductase isoform, is found in human erythrocytes. This protein is truncated, and encoded by an alternative transcript that produces only the larger, hydrophilic domain.[6] The protein contains 4 cyteine residues, Cys-203, -273, -283, and -297. Cys-283 is thought to be involved in NADH binding by chemical modification; in fact, both Cys-273 and Cys-283 are thought to be close to the NADH-binding site.[7] The NH2-terminal structure of the membrane-binding domain is CH3(CH2)12-CO-Gly-Ala-Gln-Leu-Ser-Thr-Leu-Gly-His-Met-Val-Leu-Phe-Pro-Val-Trp-Phe-Leu-Tyr-Ser-Leu-Leu-Met-Lys.[8]
Two forms of NADH-cytochrome b5 reductase are known, a membrane-bound form in somatic cells (anchored in the endoplasmic reticulum, mitochondria and other membranes) and a soluble form in erythrocytes. The membrane-bound form has both membrane-binding and catalytic domains. The soluble form has only the catalytic domain. This gene encodes both forms of the enzyme which arise from tissue-specific alternative transcripts that differ in the first exon. Mutations in this gene cause methemoglobinemias.[3]
# Function
Cytochrome b5 reductase is involved in the transfer of reducing equivalents from the physiological electron donor, NADH, via an FAD domain to the small molecules of cytochrome b5. It’s also heavily involved in many oxidation and reduction reactions, such as the reduction of methemoglobin to hemoglobin.[6] Of the two forms of NADH-cytochrome b5 reductase, the membrane-bound form exists mainly on the cytoplasmic side of the endoplasmic reticulum and functions in desaturation and elongation of fatty acids, in cholesterol biosynthesis, and in drug metabolism. The erythrocyte form is located in a soluble fraction of circulating erythrocytes and is involved in methemoglobin reduction.[3]
# Clinical significance
Mutations in the CYB5R3 gene cause methemoglobinemia types I and II. This is a rare autosomal recessive disease due to a deficiency of isoform of NADH-cytochrome b5 reductase.[9] Many mutations of this gene and the subsequent disease manifestation have been described.[10] The disease manifests as the accumulation of oxidized Fe+3 in humans.[6] Type I recessive congenital methemoglobinemia (RCM) is characterized by a deficiency of the soluble isoform and manifests as the cyanosis of skin and mucous membranes.[11] In type II, the defect affects both isoforms and thus affects more general tissues such as red blood cells, leukocytes, and all body tissues. This type is associated with mental deficiency and other neurologic symptoms, which may be because the cytochrome b5 system plays a crucial role in the desaturation of fatty acids in the body.[12] One patient was described as having a new class of this disorder, type III. This condition was characterized by a deficiency of NADH cytochrome b5 reductase in lymphocytes, platelets, and erythrocytes, but this was not associated with mental retardation.[13]
# Interactions
CYB5R3 is known to interact with CYB5A, ENO1, and SUMO2 among other proteins.[3] | https://www.wikidoc.org/index.php/CYB5R3 | |
5862f0ac4a79d62601aab460df730d4e683ac0de | wikidoc | CYFIP2 | CYFIP2
Cytoplasmic FMR1-interacting protein 2 is a protein that in humans is encoded by the CYFIP2 gene. Cytoplasmic FMR1 interacting protein is a 1253 amino acid long protein and is highly conserved sharing 99% sequence identity to the mouse protein. It is expressed mainly in brain tissues, white blood cells and the kidney.
# Interactions
CYFIP2 has been shown to interact with FMR1. CYFIP2 is a p-53 inducible protein and also interacts with the Fragile=X mental retardation protein.
# RNA editing
The pre-mRNA of this protein is subject to RNA editing. The editing site was previously recorded as a single nucleotide polymorphism (rs3207362) in the dbSNP.
## Type
A to I RNA editing is catalyzed by a family of adenosine deaminases acting on RNA (ADARs) that specifically recognize adenosines within double-stranded regions of pre-mRNAs and deaminate them to inosine. Inosines are recognised as guanosine by the cells translational machinery. There are three members of the ADAR family ADARs 1-3 with ADAR1 and ADAR2 being the only enzymatically active members. ADAR3 is thought to have a regulatory role in the brain. ADAR1 and ADAR 2 are widely expressed in tissues while ADAR3 is restricted to the brain. The double stranded regions of RNA are formed by base-pairing between residues in the close to region of the editing site with residues usually in a neighboring intron but can be an exonic sequence. The region that base pairs with the editing region is known as an Editing Complementary Sequence (ECS).
## Site
An editing site was found in the pre-mRNA of this protein. The substitution occurs within amino acid position 320 in humans and also in mice.A possible double stranded RNA region has not been detected for this pre-mRNA. No double stranded region required by ADARs has predicted.Immunoprecipitation experiments and RNA interference have shown that ADAR 2 is likely to be the main editing enzyme for this site with ADAR 1 having a minor role.
## Regulation
Editing seems to be differentially regulated in different tissues. The highest level of editing occurs in the cerebellum with lower frequency of editing detected in human lung, prostrate and uterus tissues. Editing frequency varies from 30-85% depending on tissue.{ There is some evidence for a decrease in CYFIP2 editing with increased age.
### Conservation
Editing of the pre-mRNA of this gene has been detected in mouse and chicken.
## Effects of RNA editing
### Structural
Editing results in a codon change resulting in a glutamic acid being translated instead of a lysine.
### Functional
Currently unknown but editing may have role in regulation of apoptotic functions of this protein.It is thought that since the protein is p53 inducible that the protein may be pro-apopototic. Also ADAR1 knock out mice show increase in apoptosis which indicates editing may be involved in regulation of the cellular process. | CYFIP2
Cytoplasmic FMR1-interacting protein 2 is a protein that in humans is encoded by the CYFIP2 gene.[1][2] Cytoplasmic FMR1 interacting protein is a 1253 amino acid long protein and is highly conserved sharing 99% sequence identity to the mouse protein.[1][3] It is expressed mainly in brain tissues, white blood cells and the kidney.[4]
# Interactions
CYFIP2 has been shown to interact with FMR1.[1][5] CYFIP2 is a p-53 inducible protein[6] and also interacts with the Fragile=X mental retardation protein.[7]
# RNA editing
The pre-mRNA of this protein is subject to RNA editing.[8] The editing site was previously recorded as a single nucleotide polymorphism (rs3207362) in the dbSNP.[8]
## Type
A to I RNA editing is catalyzed by a family of adenosine deaminases acting on RNA (ADARs) that specifically recognize adenosines within double-stranded regions of pre-mRNAs and deaminate them to inosine. Inosines are recognised as guanosine by the cells translational machinery. There are three members of the ADAR family ADARs 1-3 with ADAR1 and ADAR2 being the only enzymatically active members. ADAR3 is thought to have a regulatory role in the brain. ADAR1 and ADAR 2 are widely expressed in tissues while ADAR3 is restricted to the brain. The double stranded regions of RNA are formed by base-pairing between residues in the close to region of the editing site with residues usually in a neighboring intron but can be an exonic sequence. The region that base pairs with the editing region is known as an Editing Complementary Sequence (ECS).
## Site
An editing site was found in the pre-mRNA of this protein. The substitution occurs within amino acid position 320 in humans and also in mice.A possible double stranded RNA region has not been detected for this pre-mRNA.[8] No double stranded region required by ADARs has predicted.Immunoprecipitation experiments and RNA interference have shown that ADAR 2 is likely to be the main editing enzyme for this site with ADAR 1 having a minor role.[9][10]
## Regulation
Editing seems to be differentially regulated in different tissues. The highest level of editing occurs in the cerebellum with lower frequency of editing detected in human lung, prostrate and uterus tissues. Editing frequency varies from 30-85% depending on tissue.[8][9]{[10] There is some evidence for a decrease in CYFIP2 editing with increased age.[11]
### Conservation
Editing of the pre-mRNA of this gene has been detected in mouse and chicken.[8]
## Effects of RNA editing
### Structural
Editing results in a codon change resulting in a glutamic acid being translated instead of a lysine.[8]
### Functional
Currently unknown but editing may have role in regulation of apoptotic functions of this protein.It is thought that since the protein is p53 inducible that the protein may be pro-apopototic. Also ADAR1 knock out mice show increase in apoptosis which indicates editing may be involved in regulation of the cellular process.[6][8] | https://www.wikidoc.org/index.php/CYFIP2 | |
5e057a56b1572c8431639074c7a7128e193f9c42 | wikidoc | CYP1A1 | CYP1A1
Cytochrome P450, family 1, subfamily A, polypeptide 1 is a protein which in humans in encoded by the CYP1A1 gene. The protein a member of the cytochrome P450 superfamily of enzymes.
# Function
CYP1A1 is involved in phase I xenobiotic and drug metabolism (one substrate of it is theophylline). It is inhibited by fluoroquinolones and macrolides and induced by aromatic hydrocarbons.
CYP1A1 is also known as AHH (aryl hydrocarbon hydroxylase). It is involved in the metabolic activation of aromatic hydrocarbons (polycyclic aromatic hydrocarbons, PAH), for example, benzopyrene (BP), by transforming it to an epoxide. In this reaction, the oxidation of benzopyrene is catalysed by CYP1A1 to form BP-7,8-epoxide, which can be further oxidized by epoxide hydrolase (EH) to form BP-7,8-dihydrodiol. Finally CYP1A1 catalyses this intermediate to form BP-7,8-dihydrodiol-9,10-epoxide, which is the ultimate carcinogen.
# Regulation
The expression of the CYP1A1 and CYP1B1 genes are regulated by the aryl hydrocarbon receptor, a ligand activated transcription factor.
# Polymorphisms
Several polymorphisms have been identified in CYP1A1, some of which lead to more highly inducible AHH activity. CYP1A1 polymorphisms include:
- M1, T→C substitution at nucleotide 3801 in the 3'-non-coding region
- M2, A→G substitution at nucleotide 2455 leading to an amino acid change of isoleucine to valine at codon 462
- M3, T→C substitution at nucleotide 3205 in the 3'-non-coding region
- M4, C→A substitution at nucleotide 2453 leading to an amino acid change of threonine to asparagine at codon 461 | CYP1A1
Template:PBB
Cytochrome P450, family 1, subfamily A, polypeptide 1 is a protein[1] which in humans in encoded by the CYP1A1 gene.[2] The protein a member of the cytochrome P450 superfamily of enzymes.[3]
# Function
CYP1A1 is involved in phase I xenobiotic and drug metabolism (one substrate of it is theophylline). It is inhibited by fluoroquinolones and macrolides and induced by aromatic hydrocarbons.[4]
CYP1A1 is also known as AHH (aryl hydrocarbon hydroxylase). It is involved in the metabolic activation of aromatic hydrocarbons (polycyclic aromatic hydrocarbons, PAH), for example, benzopyrene (BP), by transforming it to an epoxide. In this reaction, the oxidation of benzo[a]pyrene is catalysed by CYP1A1 to form BP-7,8-epoxide, which can be further oxidized by epoxide hydrolase (EH) to form BP-7,8-dihydrodiol. Finally CYP1A1 catalyses this intermediate to form BP-7,8-dihydrodiol-9,10-epoxide, which is the ultimate carcinogen.[4]
# Regulation
The expression of the CYP1A1 and CYP1B1 genes are regulated by the aryl hydrocarbon receptor, a ligand activated transcription factor.[5]
# Polymorphisms
Several polymorphisms have been identified in CYP1A1, some of which lead to more highly inducible AHH activity. CYP1A1 polymorphisms include:[6][7][8][9]
- M1, T→C substitution at nucleotide 3801 in the 3'-non-coding region
- M2, A→G substitution at nucleotide 2455 leading to an amino acid change of isoleucine to valine at codon 462
- M3, T→C substitution at nucleotide 3205 in the 3'-non-coding region
- M4, C→A substitution at nucleotide 2453 leading to an amino acid change of threonine to asparagine at codon 461 | https://www.wikidoc.org/index.php/CYP1A1 | |
fb592394c29bd26e25ae6688ca8aa343f20170b5 | wikidoc | CYP1A2 | CYP1A2
Cytochrome P450 1A2 (abbreviated CYP1A2), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body. In humans, the CYP1A2 enzyme is encoded by the CYP1A2 gene.
# Function
CYP1A2 is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP1A2 localizes to the endoplasmic reticulum and its expression is induced by some polycyclic aromatic hydrocarbons (PAHs), some of which are found in cigarette smoke. The enzyme's endogenous substrate is unknown; however, it is able to metabolize some PAHs to carcinogenic intermediates. Other xenobiotic substrates for this enzyme include caffeine, aflatoxin B1, and paracetamol (acetaminophen). The transcript from this gene contains four Alu sequences flanked by direct repeats in the 3' untranslated region.
CYP1A2 also metabolizes polyunsaturated fatty acids into signaling molecules that have physiological as well as pathological activities. It has monoxygenase activity for certain of these fatty acids in that it metabolizes arachidonic acid to 19-hydroxyeicosatetraenoic acid (19-HETE) (see 20-Hydroxyeicosatetraenoic acid) but also has epoxygenase activity in that it metabolizes docosahexaenoic acid to epoxides, primarily 19R,20S-epoxyeicosapentaenoic acid and 19S,20R-epoxyeicosapentaenoic acid isomers (termed 19,20-EDP) and similarly metabolizes eicosapentaenoic acid to epoxides, primarily 17R,18S-eicosatetraenic acid and 17S,18R-eicosatetraenic acid isomers (termed 17,18-EEQ).
19-HETE is an inhibitor of 20-HETE, a broadly active signaling molecule, e.g. it constricts arterioles, elevates blood pressure, promotes inflammation responses, and stimulates the growth of various types of tumor cells; however the in vivo ability and significance of 19-HETE in inhibiting 20-HETE has not been demonstrated (see 20-Hydroxyeicosatetraenoic acid). The EDP (see Epoxydocosapentaenoic acid) and EEQ (see epoxyeicosatetraenoic acid) metabolites have a broad range of activities. In various animal models and in vitro studies on animal and human tissues, they decrease hypertension and pain perception; suppress inflammation; inhibit angiogenesis, endothelial cell migration and endothelial cell proliferation; and inhibit the growth and metastasis of human breast and prostate cancer cell lines. It is suggested that the EDP and EEQ metabolites function in humans as they do in animal models and that, as products of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid, the EDP and EEQ metabolites contribute to many of the beneficial effects attributed to dietary omega-3 fatty acids. EDP and EEQ metabolites are short-lived, being inactivated within seconds or minutes of formation by epoxide hydrolases, particularly soluble epoxide hydrolase, and therefore act locally.
CYP1A2 is not regarded as being a major contributor to forming the cited epoxides but could act locally in certain tissues to do so.
# Effect of diet
Expression of CYP1A2 appears to be induced by various dietary constituents. Vegetables such as cabbages, cauliflower and broccoli are known to increase levels of CYP1A2. Lower activity of CYP1A2 in South Asians appears to be due to cooking these vegetables in curries using ingredients such as cumin and turmeric, ingredients known to inhibit the enzyme.
# Ligands
Following is a table of selected substrates, inducers and inhibitors of CYP1A2.
Inhibitors of CYP1A2 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance of substrates.
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance of substrates.
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance of substrates. | CYP1A2
Cytochrome P450 1A2 (abbreviated CYP1A2), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body.[1] In humans, the CYP1A2 enzyme is encoded by the CYP1A2 gene.[2]
# Function
CYP1A2 is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP1A2 localizes to the endoplasmic reticulum and its expression is induced by some polycyclic aromatic hydrocarbons (PAHs), some of which are found in cigarette smoke. The enzyme's endogenous substrate is unknown; however, it is able to metabolize some PAHs to carcinogenic intermediates. Other xenobiotic substrates for this enzyme include caffeine, aflatoxin B1, and paracetamol (acetaminophen). The transcript from this gene contains four Alu sequences flanked by direct repeats in the 3' untranslated region.[3]
CYP1A2 also metabolizes polyunsaturated fatty acids into signaling molecules that have physiological as well as pathological activities. It has monoxygenase activity for certain of these fatty acids in that it metabolizes arachidonic acid to 19-hydroxyeicosatetraenoic acid (19-HETE) (see 20-Hydroxyeicosatetraenoic acid) but also has epoxygenase activity in that it metabolizes docosahexaenoic acid to epoxides, primarily 19R,20S-epoxyeicosapentaenoic acid and 19S,20R-epoxyeicosapentaenoic acid isomers (termed 19,20-EDP) and similarly metabolizes eicosapentaenoic acid to epoxides, primarily 17R,18S-eicosatetraenic acid and 17S,18R-eicosatetraenic acid isomers (termed 17,18-EEQ).[4]
19-HETE is an inhibitor of 20-HETE, a broadly active signaling molecule, e.g. it constricts arterioles, elevates blood pressure, promotes inflammation responses, and stimulates the growth of various types of tumor cells; however the in vivo ability and significance of 19-HETE in inhibiting 20-HETE has not been demonstrated (see 20-Hydroxyeicosatetraenoic acid). The EDP (see Epoxydocosapentaenoic acid) and EEQ (see epoxyeicosatetraenoic acid) metabolites have a broad range of activities. In various animal models and in vitro studies on animal and human tissues, they decrease hypertension and pain perception; suppress inflammation; inhibit angiogenesis, endothelial cell migration and endothelial cell proliferation; and inhibit the growth and metastasis of human breast and prostate cancer cell lines.[5][6][7][8] It is suggested that the EDP and EEQ metabolites function in humans as they do in animal models and that, as products of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid, the EDP and EEQ metabolites contribute to many of the beneficial effects attributed to dietary omega-3 fatty acids.[5][8][9] EDP and EEQ metabolites are short-lived, being inactivated within seconds or minutes of formation by epoxide hydrolases, particularly soluble epoxide hydrolase, and therefore act locally.
CYP1A2 is not regarded as being a major contributor to forming the cited epoxides[8] but could act locally in certain tissues to do so.
# Effect of diet
Expression of CYP1A2 appears to be induced by various dietary constituents.[10] Vegetables such as cabbages, cauliflower and broccoli are known to increase levels of CYP1A2. Lower activity of CYP1A2 in South Asians appears to be due to cooking these vegetables in curries using ingredients such as cumin and turmeric, ingredients known to inhibit the enzyme.[11]
# Ligands
Following is a table of selected substrates, inducers and inhibitors of CYP1A2.
Inhibitors of CYP1A2 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance of substrates.[12]
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance of substrates.[12]
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance of substrates.[12] | https://www.wikidoc.org/index.php/CYP1A2 | |
2155cc915d033d28edbaecb19e379871ae5a1d5a | wikidoc | CYP1B1 | CYP1B1
Cytochrome P450 1B1 is an enzyme that in humans is encoded by the CYP1B1 gene.
# Function
CYP1B1 belongs to the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids. The enzyme encoded by this gene localizes to the endoplasmic reticulum (ER) and metabolizes procarcinogens such as polycyclic aromatic hydrocarbons and 17beta-estradiol.
Despite over 20 years of research on CYP1A1 and CYP1A2, CYP1B1 was not identified and sequenced until 1994. Nucleic and amino acid analysis showed approximately 40% identity with CYP1A1. Despite this similarity, these two enzymes have very different catalytic efficiencies and metabolites when incubated with common substrates, such as retinoic acid and arachidonic acid. Recently CYP1B1 has been shown to be physiologically important in fetal development, since mutations in CYP1B1 are linked with a form of primary congenital glaucoma.
CYP1A1 and CYP1B1 are regulated by the aryl hydrocarbon receptor, a ligand activated transcription factor. They are part of the Phase I reactions of drug metabolism.
# Clinical significance
Mutations in this gene have been associated with primary congenital glaucoma; therefore it is thought that the enzyme also metabolizes a signaling molecule involved in eye development, possibly a steroid. | CYP1B1
Cytochrome P450 1B1 is an enzyme that in humans is encoded by the CYP1B1 gene.[1]
# Function
CYP1B1 belongs to the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids. The enzyme encoded by this gene localizes to the endoplasmic reticulum (ER) and metabolizes procarcinogens such as polycyclic aromatic hydrocarbons and 17beta-estradiol.
Despite over 20 years of research on CYP1A1 and CYP1A2, CYP1B1 was not identified and sequenced until 1994. Nucleic and amino acid analysis showed approximately 40% identity with CYP1A1. Despite this similarity, these two enzymes have very different catalytic efficiencies and metabolites when incubated with common substrates, such as retinoic acid and arachidonic acid. Recently CYP1B1 has been shown to be physiologically important in fetal development, since mutations in CYP1B1 are linked with a form of primary congenital glaucoma.
CYP1A1 and CYP1B1 are regulated by the aryl hydrocarbon receptor, a ligand activated transcription factor. They are part of the Phase I reactions of drug metabolism.
# Clinical significance
Mutations in this gene have been associated with primary congenital glaucoma; therefore it is thought that the enzyme also metabolizes a signaling molecule involved in eye development, possibly a steroid.[1] | https://www.wikidoc.org/index.php/CYP1B1 | |
35284ff219c771021961ce3ec01d7a53a2c21e6f | wikidoc | CYP2A6 | CYP2A6
Cytochrome P450 2A6 (abbreviated CYP2A6) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. CYP2A6 is the primary enzyme responsible for the oxidation of nicotine and cotinine. It is also involved in the metabolism of several pharmaceuticals, carcinogens, and a number of coumarin-type alkaloids. CYP2A6 is the only enzyme in the human body that appreciably catalyzes the 7-hydroxylation of coumarin, such that the formation of the product of this reaction, 7-hydroxycoumarin, is used as a probe for CYP2A6 activity.
The CYP2A6 gene is part of a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q. The gene was formerly referred to as CYP2A3; however, it has been renamed CYP2A6.
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.
- ↑ The interactive pathway map can be edited at WikiPathways: "FluoropyrimidineActivity_WP1601"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
# Distribution
CYP2A6 localizes to the endoplasmic reticulum and is found predominantly in the liver.
# Variability
Significant interindividual variability in CYP2A6 apoprotein and mRNA levels has been observed.
# Induction
CYP2A6 is known to be inducible by phenobarbital and rifampicin, and it is suspected that other antiepileptic drugs may also have this effect.
# CYP2A6 Ligands | CYP2A6
Cytochrome P450 2A6 (abbreviated CYP2A6) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. CYP2A6 is the primary enzyme responsible for the oxidation of nicotine and cotinine. It is also involved in the metabolism of several pharmaceuticals, carcinogens, and a number of coumarin-type alkaloids. CYP2A6 is the only enzyme in the human body that appreciably catalyzes the 7-hydroxylation of coumarin, such that the formation of the product of this reaction, 7-hydroxycoumarin, is used as a probe for CYP2A6 activity.
The CYP2A6 gene is part of a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q. The gene was formerly referred to as CYP2A3; however, it has been renamed CYP2A6.[1]
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.[§ 1]
- ↑ The interactive pathway map can be edited at WikiPathways: "FluoropyrimidineActivity_WP1601"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
# Distribution
CYP2A6 localizes to the endoplasmic reticulum and is found predominantly in the liver.
# Variability
Significant interindividual variability in CYP2A6 apoprotein and mRNA levels has been observed.
# Induction
CYP2A6 is known to be inducible by phenobarbital and rifampicin, and it is suspected that other antiepileptic drugs may also have this effect.
# CYP2A6 Ligands | https://www.wikidoc.org/index.php/CYP2A6 | |
3776569733c5cc6c2c45ce49db381d4c9ee373cb | wikidoc | CYP2B6 | CYP2B6
Cytochrome P450 2B6 is an enzyme that in humans is encoded by the CYP2B6 gene. CYP2B6 is a member of the Cytochrome P450 group of enzymes. Along with CYP2A6, it is involved with metabolizing nicotine, along with many other substances.
# Function
This gene, CYP2B6, encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and its expression is induced by phenobarbital. The enzyme is known to metabolize some xenobiotics, such as the anti-cancer drugs cyclophosphamide and ifosphamide.
# Gene
Transcript variants for this gene have been described; however, it has not been resolved whether these transcripts are in fact produced by this gene or by a closely related pseudogene, CYP2B7. Both the gene and the pseudogene are located in the middle of a CYP2A pseudogene found in a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q.
# CYP2B6 ligands
Following is a table of selected substrates, inducers and inhibitors of CYP2B6.
Inhibitors of CYP2B6 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance. | CYP2B6
Cytochrome P450 2B6 is an enzyme that in humans is encoded by the CYP2B6 gene.[1] CYP2B6 is a member of the Cytochrome P450 group of enzymes. Along with CYP2A6, it is involved with metabolizing nicotine, along with many other substances.[1]
# Function
This gene, CYP2B6, encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and its expression is induced by phenobarbital. The enzyme is known to metabolize some xenobiotics, such as the anti-cancer drugs cyclophosphamide and ifosphamide.[1]
# Gene
Transcript variants for this gene have been described; however, it has not been resolved whether these transcripts are in fact produced by this gene or by a closely related pseudogene, CYP2B7. Both the gene and the pseudogene are located in the middle of a CYP2A pseudogene found in a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q.[1]
# CYP2B6 ligands
Following is a table of selected substrates, inducers and inhibitors of CYP2B6.
Inhibitors of CYP2B6 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.[2]
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.[2]
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.[2] | https://www.wikidoc.org/index.php/CYP2B6 | |
a60f2bce26a336fac9d84484ce074232f96bd433 | wikidoc | CYP2C8 | CYP2C8
Cytochrome P4502C8 (abbreviated CYP2C8), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body. Cytochrome P4502C8 also possesses epoxygenase activity, i.e. it metabolizes long-chain polyunsaturated fatty acids, e.g. arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and Linoleic acid to their biologically active epoxides.
# CYP2C8 ligands
Following is a table of selected substrates, inducers and inhibitors of 2C8.
Inhibitors of CYP2C8 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a five-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
- Moderate inhibitor being one that causes at least a two-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
- Weak inhibitor being one that causes at least a 1.25-fold but less than two-fold increase in the plasma AUC values, or 20-50% decrease in clearance.
Where classes of agents are listed, there may be exceptions within the class.
# Epoxygenase activity
CYP2C8 also possesses epoxygenase activitiy: it is one of the principal enzymes responsible for attacking various long-chain polyunsaturated fatty acids at their double (i.e. alkene) bonds to form epoxide products that act as signaling agents. It metabolizes: 1) arachidonic acid to various epoxyeicosatrienoic acids (also termed EETs); 2) linoleic acid to 9,10-epoxy octadecaenoic acids (also termed vernolic acid, linoleic acid 9:10-oxide, or leukotoxin) and 12,13-epoxy-octadecaenoic (also termed coronaric acid, linoleic acid 12,13-oxide, or isoleukotoxin); 3) docosohexaenoic acid to various epoxydocosapentaenoic acids (also termed EDPs); and 4) eicosapentaenoic acid to various epoxyeicosatetraenoic acids (also termed EEQs).
Along with CYP2C8, CYP2C9, CYP2C19, CYP2J2, and possibly CYP2S1 are the main producers of EETs and, very likely, EEQs, EDPs, and the epoxides of linoleic acid. | CYP2C8
Cytochrome P4502C8 (abbreviated CYP2C8), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body. Cytochrome P4502C8 also possesses epoxygenase activity, i.e. it metabolizes long-chain polyunsaturated fatty acids, e.g. arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and Linoleic acid to their biologically active epoxides.[1]
# CYP2C8 ligands
Following is a table of selected substrates, inducers and inhibitors of 2C8.
Inhibitors of CYP2C8 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a five-fold increase in the plasma AUC values, or more than 80% decrease in clearance.[2]
- Moderate inhibitor being one that causes at least a two-fold increase in the plasma AUC values, or 50-80% decrease in clearance.[2]
- Weak inhibitor being one that causes at least a 1.25-fold but less than two-fold increase in the plasma AUC values, or 20-50% decrease in clearance.[2]
Where classes of agents are listed, there may be exceptions within the class.
# Epoxygenase activity
CYP2C8 also possesses epoxygenase activitiy: it is one of the principal enzymes responsible for attacking various long-chain polyunsaturated fatty acids at their double (i.e. alkene) bonds to form epoxide products that act as signaling agents. It metabolizes: 1) arachidonic acid to various epoxyeicosatrienoic acids (also termed EETs); 2) linoleic acid to 9,10-epoxy octadecaenoic acids (also termed vernolic acid, linoleic acid 9:10-oxide, or leukotoxin) and 12,13-epoxy-octadecaenoic (also termed coronaric acid, linoleic acid 12,13-oxide, or isoleukotoxin); 3) docosohexaenoic acid to various epoxydocosapentaenoic acids (also termed EDPs); and 4) eicosapentaenoic acid to various epoxyeicosatetraenoic acids (also termed EEQs).[4][5][6]
Along with CYP2C8, CYP2C9, CYP2C19, CYP2J2, and possibly CYP2S1 are the main producers of EETs and, very likely, EEQs, EDPs, and the epoxides of linoleic acid.[7][8] | https://www.wikidoc.org/index.php/CYP2C8 | |
06e459ccb68983493de2777fcf07022fa28cf4c8 | wikidoc | CYP2C9 | CYP2C9
Cytochrome P450 2C9 (abbreviated CYP2C9) is an enzyme that in humans is encoded by the CYP2C9 gene.
# Function
CYP2C9 is an important cytochrome P450 enzyme with a major role in the oxidation of both xenobiotic and endogenous compounds. CYP2C9 makes up about 18% of the cytochrome P450 protein in liver microsomes (data only for antifungal). Some 100 therapeutic drugs are metabolized by CYP2C9, including drugs with a narrow therapeutic index such as warfarin and phenytoin and other routinely prescribed drugs such as acenocoumarol, tolbutamide, losartan, glipizide, and some nonsteroidal anti-inflammatory drugs. By contrast, the known extrahepatic CYP2C9 often metabolizes important endogenous compound such as serotonin and, owing to its epoxygenase activity, various polyunsaturated fatty acids, converting these fatty acids to a wide range of biological active products.
In particular, CYP2C9 metabolizes arachidonic acid to the following eicosatrienoic acid epoxide (termed EETs) stereoisomer sets: 5R,6S-epoxy-8Z,11Z,14Z-eicosatetrienoic and 5S,6R-epoxy-8Z,11Z,14Z-eicosatetrienoic acids; 11R,12S-epoxy-8Z,11Z,14Z-eicosatetrienoic and 11S,12R-epoxy-5Z,8Z,14Z-eicosatetrienoic acids; and 14R,15S-epoxy-5Z,8Z,11Z-eicosatetrainoic and 14S,15R-epoxy-5Z,8Z,11Z-eicosatetrainoic acids. It likewise metablizes docosahexaenoic acid to epoxydocosapentaenoic acids (EDPs; primarily 19,20-epoxy-eicosapentaenoic acid isomers ) and eicosapentaenoic acid to epoxyeicosatetraenoic acids (EEQs, primarily 17,18-EEQ and 14,15-EEQ isomers). Animal model and a limited number of human studies implicate these epoxides in reducing hypertension; protecting against the Myocardial infarction and other insults to the heart; promoting the growth and metastasis of certain cancers; inhibiting inflammation; stimulating blood vessel formation; and possessing a variety of actions on neural tissues including modulating Neurohormone release and blocking pain perception (see epoxyeicosatrienoic acid and epoxygenase pages).
In vitro studies on human and animal cells and tissues and in vivo animal model studies indicate that certain EDPs and EEQs (16,17-EDPs, 19,20-EDPs, 17,18-EEQs have been most often examined) have actions which often oppose those of another product of CYP450 enzymes (e.g. CYP4A1, CYP4A11, CYP4F2, CYP4F3A, and CYP4F3B) viz., 20-Hydroxyeicosatetraenoic acid (20-HETE), principally in the areas of blood pressure regulation, blood vessel thrombosis, and cancer growth (see 20-Hydroxyeicosatetraenoic acid, Epoxyeicosatetraenoic acid, and Epoxydocosapentaenoic acid sections on activities and clinical significance). Such studies also indicate that the EPAs and EEQs are: 1) more potent than EETs in decreasing hypertension and pain perception; 2) more potent than or equal in potency to the EETs in suppressing inflammation; and 3) act oppositely from the EETs in that they inhibit angiogenesis, endothelial cell migration, endothelial cell proliferation, and the growth and metastasis of human breast and prostate cancer cell lines whereas EETs have stimulatory effects in each of these systems. Consumption of omega-3 fatty acid-rich diets dramatically raises the serum and tissue levels of EDPs and EEQs in animals as well as humans and in humans are by far the most prominent change in the profile of PUFA metabolites caused by dietary omega-3 fatty acids.
CYP2C9 may also metabolize linoleic acid to the potentially very toxic products, vernolic acid (also termed leukotoxin) and coronaric acid (also termed isoleukotoxin); these linoleic acid epoxides cause multiple organ failure and acute respiratory distress in animal models and may contribute to these syndromes in humans.
# Pharmacogenomics
Genetic polymorphism exists for CYP2C9 expression because the CYP2C9 gene is highly polymorphic. More than 50 single nucleotide polymorphisms (SNPs) have been described in the regulatory and coding regions of the CYP2C9 gene; some of them are associated with reduced enzyme activity compared with wild type in vitro.
Multiple in vivo studies also show that several mutant CYP2C9 genotypes are associated with significant reduction of in metabolism and daily dose requirements of selected CYP2C9 substrate. In fact, adverse drug reactions (ADRs) often result from unanticipated changes in CYP2C9 enzyme activity secondary to genetic polymorphisms. Especially for CYP2C9 substrates such as warfarin and phenytoin, diminished metabolic capacity because of genetic polymorphisms or drug-drug interactions can lead to toxicity at normal therapeutic doses.
Allele frequencies(%) of CYP2C9 polymorphism
# CYP2C9 Ligands
Most inhibitors of CYP2C9 are competitive inhibitors. Noncompetitive inhibitors of CYP2C9 include nifedipine, phenethyl isothiocyanate, medroxyprogesterone acetate and 6-hydroxyflavone. It was indicated that the noncompetitive binding site of 6-hydroxyflavone is the reported allosteric binding site of the CYP2C9 enzyme.
Following is a table of selected substrates, inducers and inhibitors of CYP2C9. Where classes of agents are listed, there may be exceptions within the class.
Inhibitors of CYP2C9 can be classified by their potency, such as:
- Strong being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
- Moderate being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
- Weak being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.
# Epoxygenase activity
CYP2C9 attacks various long-chain polyunsaturated fatty acids at their double (i.e. alkene) bonds to form epoxide products that act as signaling molecules. It along with CYP2C8, CYP2C19, CYP2J2, and possibly CYP2S1 are the principle enzymes which metabolizes 1) arachidonic acid to various epoxyeicosatrienoic acids (also termed EETs); 2) linoleic acid to 9,10-epoxy octadecaenoic acids (also termed vernolic acid, linoleic acid 9:10-oxide, or leukotoxin) and 12,13-epoxy-octadecaenoic (also termed coronaric acid, linoleic acid 12,13-oxide, or isoleukotoxin); 3) docosohexaenoic acid to various epoxydocosapentaenoic acids (also termed EDPs); and 4) eicosapentaenoic acid to various epoxyeicosatetraenoic acids (also termed EEQs). Animal model studies implicate these epoxides in regulating: hypertension, Myocardial infarction and other insults to the heart, the growth of various cancers, inflammation, blood vessel formation, and pain perception; limited studies suggest but have not proven that these epoxides may function similarly in humans (see epoxyeicosatrienoic acid and epoxygenase pages). Since the consumption of omega-3 fatty acid-rich diets dramatically raises the serum and tissue levels of the EDP and EEQ metabolites of the omega-3 fatty acid, i.e. docosahexaenoic and eicosapentaenoic acids, in animals and humans and in humans is the most prominent change in the profile of PUFA metabolites caused by dietary omega-3 fatty acids, EPA and EEQs may be responsible for at least some of the beneficial effects ascribed to dietary omega-3 fatty acids. | CYP2C9
Cytochrome P450 2C9 (abbreviated CYP2C9) is an enzyme that in humans is encoded by the CYP2C9 gene.[1][2]
# Function
CYP2C9 is an important cytochrome P450 enzyme with a major role in the oxidation of both xenobiotic and endogenous compounds. CYP2C9 makes up about 18% of the cytochrome P450 protein in liver microsomes (data only for antifungal). Some 100 therapeutic drugs are metabolized by CYP2C9, including drugs with a narrow therapeutic index such as warfarin and phenytoin and other routinely prescribed drugs such as acenocoumarol, tolbutamide, losartan, glipizide, and some nonsteroidal anti-inflammatory drugs. By contrast, the known extrahepatic CYP2C9 often metabolizes important endogenous compound such as serotonin and, owing to its epoxygenase activity, various polyunsaturated fatty acids, converting these fatty acids to a wide range of biological active products.[3][4]
In particular, CYP2C9 metabolizes arachidonic acid to the following eicosatrienoic acid epoxide (termed EETs) stereoisomer sets: 5R,6S-epoxy-8Z,11Z,14Z-eicosatetrienoic and 5S,6R-epoxy-8Z,11Z,14Z-eicosatetrienoic acids; 11R,12S-epoxy-8Z,11Z,14Z-eicosatetrienoic and 11S,12R-epoxy-5Z,8Z,14Z-eicosatetrienoic acids; and 14R,15S-epoxy-5Z,8Z,11Z-eicosatetrainoic and 14S,15R-epoxy-5Z,8Z,11Z-eicosatetrainoic acids. It likewise metablizes docosahexaenoic acid to epoxydocosapentaenoic acids (EDPs; primarily 19,20-epoxy-eicosapentaenoic acid isomers [i.e. 10,11-EDPs]) and eicosapentaenoic acid to epoxyeicosatetraenoic acids (EEQs, primarily 17,18-EEQ and 14,15-EEQ isomers).[5] Animal model and a limited number of human studies implicate these epoxides in reducing hypertension; protecting against the Myocardial infarction and other insults to the heart; promoting the growth and metastasis of certain cancers; inhibiting inflammation; stimulating blood vessel formation; and possessing a variety of actions on neural tissues including modulating Neurohormone release and blocking pain perception (see epoxyeicosatrienoic acid and epoxygenase pages).[4]
In vitro studies on human and animal cells and tissues and in vivo animal model studies indicate that certain EDPs and EEQs (16,17-EDPs, 19,20-EDPs, 17,18-EEQs have been most often examined) have actions which often oppose those of another product of CYP450 enzymes (e.g. CYP4A1, CYP4A11, CYP4F2, CYP4F3A, and CYP4F3B) viz., 20-Hydroxyeicosatetraenoic acid (20-HETE), principally in the areas of blood pressure regulation, blood vessel thrombosis, and cancer growth (see 20-Hydroxyeicosatetraenoic acid, Epoxyeicosatetraenoic acid, and Epoxydocosapentaenoic acid sections on activities and clinical significance). Such studies also indicate that the EPAs and EEQs are: 1) more potent than EETs in decreasing hypertension and pain perception; 2) more potent than or equal in potency to the EETs in suppressing inflammation; and 3) act oppositely from the EETs in that they inhibit angiogenesis, endothelial cell migration, endothelial cell proliferation, and the growth and metastasis of human breast and prostate cancer cell lines whereas EETs have stimulatory effects in each of these systems.[6][7][8][9] Consumption of omega-3 fatty acid-rich diets dramatically raises the serum and tissue levels of EDPs and EEQs in animals as well as humans and in humans are by far the most prominent change in the profile of PUFA metabolites caused by dietary omega-3 fatty acids.[6][9][10]
CYP2C9 may also metabolize linoleic acid to the potentially very toxic products, vernolic acid (also termed leukotoxin) and coronaric acid (also termed isoleukotoxin); these linoleic acid epoxides cause multiple organ failure and acute respiratory distress in animal models and may contribute to these syndromes in humans.[4]
# Pharmacogenomics
Genetic polymorphism exists for CYP2C9 expression because the CYP2C9 gene is highly polymorphic. More than 50 single nucleotide polymorphisms (SNPs) have been described in the regulatory and coding regions of the CYP2C9 gene;[11] some of them are associated with reduced enzyme activity compared with wild type in vitro.[citation needed]
Multiple in vivo studies also show that several mutant CYP2C9 genotypes are associated with significant reduction of in metabolism and daily dose requirements of selected CYP2C9 substrate. In fact, adverse drug reactions (ADRs) often result from unanticipated changes in CYP2C9 enzyme activity secondary to genetic polymorphisms. Especially for CYP2C9 substrates such as warfarin and phenytoin, diminished metabolic capacity because of genetic polymorphisms or drug-drug interactions can lead to toxicity at normal therapeutic doses.[12][13]
Allele frequencies(%) of CYP2C9 polymorphism
# CYP2C9 Ligands
Most inhibitors of CYP2C9 are competitive inhibitors. Noncompetitive inhibitors of CYP2C9 include nifedipine,[14][15] phenethyl isothiocyanate,[16] medroxyprogesterone acetate[17] and 6-hydroxyflavone. It was indicated that the noncompetitive binding site of 6-hydroxyflavone is the reported allosteric binding site of the CYP2C9 enzyme.[18]
Following is a table of selected substrates, inducers and inhibitors of CYP2C9. Where classes of agents are listed, there may be exceptions within the class.
Inhibitors of CYP2C9 can be classified by their potency, such as:
- Strong being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.[19]
- Moderate being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.[19]
- Weak being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.[19][20]
# Epoxygenase activity
CYP2C9 attacks various long-chain polyunsaturated fatty acids at their double (i.e. alkene) bonds to form epoxide products that act as signaling molecules. It along with CYP2C8, CYP2C19, CYP2J2, and possibly CYP2S1 are the principle enzymes which metabolizes 1) arachidonic acid to various epoxyeicosatrienoic acids (also termed EETs); 2) linoleic acid to 9,10-epoxy octadecaenoic acids (also termed vernolic acid, linoleic acid 9:10-oxide, or leukotoxin) and 12,13-epoxy-octadecaenoic (also termed coronaric acid, linoleic acid 12,13-oxide, or isoleukotoxin); 3) docosohexaenoic acid to various epoxydocosapentaenoic acids (also termed EDPs); and 4) eicosapentaenoic acid to various epoxyeicosatetraenoic acids (also termed EEQs).[4] Animal model studies implicate these epoxides in regulating: hypertension, Myocardial infarction and other insults to the heart, the growth of various cancers, inflammation, blood vessel formation, and pain perception; limited studies suggest but have not proven that these epoxides may function similarly in humans (see epoxyeicosatrienoic acid and epoxygenase pages).[4] Since the consumption of omega-3 fatty acid-rich diets dramatically raises the serum and tissue levels of the EDP and EEQ metabolites of the omega-3 fatty acid, i.e. docosahexaenoic and eicosapentaenoic acids, in animals and humans and in humans is the most prominent change in the profile of PUFA metabolites caused by dietary omega-3 fatty acids, EPA and EEQs may be responsible for at least some of the beneficial effects ascribed to dietary omega-3 fatty acids.[32][33][34] | https://www.wikidoc.org/index.php/CYP2C9 | |
2545007bdaf828b329b7572d2850dc53df1dea3a | wikidoc | CYP2D6 | CYP2D6
Cytochrome P450 2D6 (CYP2D6) is an enzyme that in humans is encoded by the CYP2D6 gene. CYP2D6 is primarily expressed in the liver. It is also highly expressed in areas of the central nervous system, including the substantia nigra.
CYP2D6, a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. In particular, CYP2D6 is responsible for the metabolism and elimination of approximately 25% of clinically used drugs, via the addition or removal of certain functional groups – specifically, hydroxylation, demethylation, and dealkylation. Other drugs, known as prodrugs, are activated by the action of CYP2D6. This enzyme also metabolizes several endogenous substances, such as hydroxytryptamines, neurosteroids, and both m-tyramine and p-tyramine which CYP2D6 metabolizes into dopamine in the brain and liver.
Considerable variation exists in the efficiency and amount of CYP2D6 enzyme produced between individuals. Hence, for drugs that are metabolized by CYP2D6 (that is, are CYP2D6 substrates), certain individuals will eliminate these drugs quickly (ultrarapid metabolizers) while others slowly (poor metabolizers). If a drug is metabolized too quickly, it may decrease the drug's efficacy while if the drug is metabolized too slowly, toxicity may result. So, the dose of the drug may have to be adjusted to take into account of the speed at which it is metabolized by CYP2D6.
Other drugs may function as inhibitors of CYP2D6 activity or inducers of CYP2D6 enzyme expression that will lead to decreased or increased CYP2D6 activity respectively. If such a drug is taken at the same time as a second drug that is a CYP2D6 substrate, the first drug may affect the elimination rate of the second through what is known as a drug-drug interaction.
# Gene
The gene is located near two cytochrome P450 pseudogenes on chromosome 22q13.1. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.
# Genotype/phenotype variability
CYP2D6 shows the largest phenotypical variability among the CYPs, largely due to genetic polymorphism. The genotype accounts for normal, reduced, and non-existent CYP2D6 function in subjects. Pharmacogenomic tests are now available to identify patients with variations in the CYP2D6 allele and have been shown to have widespread use in clinical practice.
The CYP2D6 function in any particular subject may be described as one of the following:
- poor metabolizer – little or no CYP2D6 function
- intermediate metabolizers – metabolize drugs at a rate somewhere between the poor and extensive metabolizers
- extensive metabolizer – normal CYP2D6 function
- ultrarapid metabolizer – multiple copies of the CYP2D6 gene are expressed, so greater-than-normal CYP2D6 function occurs
A patient's CYP2D6 phenotype is often clinically determined via the administration of debrisoquine (a selective CYP2D6 substrate) and subsequent plasma concentration assay of the debrisoquine metabolite (4-hydroxydebrisoquine).
The type of CYP2D6 function of an individual may influence the person's response to different doses of drugs that CYP2D6 metabolizes. The nature of the effect on the drug response depends not only on the type of CYP2D6 function, but also on the extent to which processing of the drug by CYP2D6 results in a chemical that has an effect that is similar, stronger, or weaker than the original drug, or no effect at all. For example, if CYP2D6 converts a drug that has a strong effect into a substance that has a weaker effect, then poor metabolizers (weak CYP2D6 function) will have an exaggerated response to the drug and stronger side-effects; conversely, if CYP2D6 converts a different drug into a substance that has a greater effect than its parent chemical, then ultrarapid metabolizers (strong CYP2D6 function) will have an exaggerated response to the drug and stronger side-effects.
# Genetic basis of variability
The genetic basis for CYP2D6-mediated metabolic variability is the CYP2D6 allele, located on chromosome 22. Subjects possessing certain allelic variants will show normal, decreased, or no CYP2D6 function, depending on the allele. Pharmacogenomic tests are now available to identify patients with variations in the CYP2D6 allele and have been shown to have widespread use in clinical practice.
# Ethnic factors in variability
Race is a factor in the occurrence of CYP2D6 variability. The lack of the liver cytochrome CYP2D6 enzyme occurs approximately in 7–10% in white populations, and is lower in most other ethnic groups such as Asians and African-Americans at 2% each. The occurrence of CYP2D6 ultrarapid metabolizers appears to be greater among Middle Eastern and North African populations.
Caucasians with European descent predominantly (around 71%) have the functional group of CYP2D6 alleles, while functional alleles represent only around 50% of the allele frequency in populations of Asian descent.
This variability is accounted for by the differences in the prevalence of various CYP2D6 alleles among the populations–approximately 10% of whites are intermediate metabolizers, due to decreased CYP2D6 function, because they appear to have the non-functional CYP2D6*4 allele, while approximately 50% of Asians possess the decreased functioning CYP2D6*10 allele.
# Ligands
Following is a table of selected substrates, inducers and inhibitors of CYP2D6. Where classes of agents are listed, there may be exceptions within the class.
Inhibitors of CYP2D6 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.
## Dopamine biosynthesis | CYP2D6
Cytochrome P450 2D6 (CYP2D6) is an enzyme that in humans is encoded by the CYP2D6 gene. CYP2D6 is primarily expressed in the liver. It is also highly expressed in areas of the central nervous system, including the substantia nigra.
CYP2D6, a member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics in the body. In particular, CYP2D6 is responsible for the metabolism and elimination of approximately 25% of clinically used drugs, via the addition or removal of certain functional groups – specifically, hydroxylation, demethylation, and dealkylation.[1] Other drugs, known as prodrugs, are activated by the action of CYP2D6. This enzyme also metabolizes several endogenous substances, such as hydroxytryptamines, neurosteroids, and both m-tyramine and p-tyramine which CYP2D6 metabolizes into dopamine in the brain and liver.[1][2]
Considerable variation exists in the efficiency and amount of CYP2D6 enzyme produced between individuals. Hence, for drugs that are metabolized by CYP2D6 (that is, are CYP2D6 substrates), certain individuals will eliminate these drugs quickly (ultrarapid metabolizers) while others slowly (poor metabolizers). If a drug is metabolized too quickly, it may decrease the drug's efficacy while if the drug is metabolized too slowly, toxicity may result.[3] So, the dose of the drug may have to be adjusted to take into account of the speed at which it is metabolized by CYP2D6.[4]
Other drugs may function as inhibitors of CYP2D6 activity or inducers of CYP2D6 enzyme expression that will lead to decreased or increased CYP2D6 activity respectively. If such a drug is taken at the same time as a second drug that is a CYP2D6 substrate, the first drug may affect the elimination rate of the second through what is known as a drug-drug interaction.[3]
# Gene
The gene is located near two cytochrome P450 pseudogenes on chromosome 22q13.1. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[5]
# Genotype/phenotype variability
CYP2D6 shows the largest phenotypical variability among the CYPs, largely due to genetic polymorphism. The genotype accounts for normal, reduced, and non-existent CYP2D6 function in subjects. Pharmacogenomic tests are now available to identify patients with variations in the CYP2D6 allele and have been shown to have widespread use in clinical practice.[6]
The CYP2D6 function in any particular subject may be described as one of the following:[7]
- poor metabolizer – little or no CYP2D6 function
- intermediate metabolizers – metabolize drugs at a rate somewhere between the poor and extensive metabolizers
- extensive metabolizer – normal CYP2D6 function
- ultrarapid metabolizer – multiple copies of the CYP2D6 gene are expressed, so greater-than-normal CYP2D6 function occurs
A patient's CYP2D6 phenotype is often clinically determined via the administration of debrisoquine (a selective CYP2D6 substrate) and subsequent plasma concentration assay of the debrisoquine metabolite (4-hydroxydebrisoquine).[8]
The type of CYP2D6 function of an individual may influence the person's response to different doses of drugs that CYP2D6 metabolizes. The nature of the effect on the drug response depends not only on the type of CYP2D6 function, but also on the extent to which processing of the drug by CYP2D6 results in a chemical that has an effect that is similar, stronger, or weaker than the original drug, or no effect at all. For example, if CYP2D6 converts a drug that has a strong effect into a substance that has a weaker effect, then poor metabolizers (weak CYP2D6 function) will have an exaggerated response to the drug and stronger side-effects; conversely, if CYP2D6 converts a different drug into a substance that has a greater effect than its parent chemical, then ultrarapid metabolizers (strong CYP2D6 function) will have an exaggerated response to the drug and stronger side-effects.[9]
# Genetic basis of variability
The genetic basis for CYP2D6-mediated metabolic variability is the CYP2D6 allele, located on chromosome 22. Subjects possessing certain allelic variants will show normal, decreased, or no CYP2D6 function, depending on the allele. Pharmacogenomic tests are now available to identify patients with variations in the CYP2D6 allele and have been shown to have widespread use in clinical practice.[6]
# Ethnic factors in variability
Race is a factor in the occurrence of CYP2D6 variability. The lack of the liver cytochrome CYP2D6 enzyme occurs approximately in 7–10% in white populations, and is lower in most other ethnic groups such as Asians and African-Americans at 2% each.[12] The occurrence of CYP2D6 ultrarapid metabolizers appears to be greater among Middle Eastern and North African populations.[13]
Caucasians with European descent predominantly (around 71%) have the functional group of CYP2D6 alleles, while functional alleles represent only around 50% of the allele frequency in populations of Asian descent.[14]
This variability is accounted for by the differences in the prevalence of various CYP2D6 alleles among the populations–approximately 10% of whites are intermediate metabolizers, due to decreased CYP2D6 function, because they appear to have the non-functional CYP2D6*4 allele,[10] while approximately 50% of Asians possess the decreased functioning CYP2D6*10 allele.[10]
# Ligands
Following is a table of selected substrates, inducers and inhibitors of CYP2D6. Where classes of agents are listed, there may be exceptions within the class.
Inhibitors of CYP2D6 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.[15]
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.[15]
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.[15]
## Dopamine biosynthesis | https://www.wikidoc.org/index.php/CYP2D6 | |
503e8d921fb9e07b0d50ae13852ebd118cd148e5 | wikidoc | CYP2E1 | CYP2E1
Cytochrome P450 2E1 (abbreviated CYP2E1, EC 1.14.13.n7) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. This class of enzymes is divided up into a number of subcategories, including CYP1, CYP2, and CYP3, which as a group are largely responsible for the breakdown of foreign compounds in mammals.
The CYP2 subfamily is responsible for the majority of P450-mediated drug metabolism in humans. While CYP2E1 itself carries out a relatively low number of these reactions (~4% of known P450-mediated drug oxidations), it and related enzymes CYP1A2 and CYP3A4 are responsible for the breakdown of a large number of toxic environmental chemicals and carcinogens that enter the body, in addition to basic metabolic reactions such as fatty acid oxidations.
# Function
CYP2E1 is a membrane protein expressed in high levels in the liver, where it composes nearly 50% of the total hepatic cytochrome P450 mRNA and 7% of the hepatic cytochrome P450 protein. The liver is therefore where most drugs undergo deactivation by CYP2E1, either directly or by facilitated excretion from the body.
CYP2E1 metabolizes mostly small, polar molecules, including toxic laboratory chemicals such as dimethylformamide, aniline, and halogenated hydrocarbons (see table below). While these oxidations are often of benefit to the body, certain carcinogens and toxins are bioactivated by CYP2E1, implicating the enzyme in the onset of hepatotoxicity caused by certain classes of drugs (see disease relevance section below).
CYP2E1 also plays a role in several important metabolic reactions, including the conversion of ethanol to acetaldehyde and to acetate in humans, where it works alongside alcohol dehydrogenase and aldehyde dehydrogenase. In the conversion sequence of acetyl-CoA to glucose, CYP2E1 transforms acetone via hydroxyacetone (acetol) into propylene glycol and methylglyoxal, the precursors of pyruvate, acetate and lactate.
CYP2E1 also carries out the metabolism of endogenous fatty acids such as the ω-1 hydroxylation of fatty acids such as arachidonic acid, involving it in important signaling pathways that may link it to diabetes and obesity. Thus, it acts as a monooxygenase to metabolize arachidonic acid to 19-hydroxyeicosatetraenoic acid (19-HETE) (see 20-Hydroxyeicosatetraenoic acid). However, it also acts as an epoxygenase activity to metabolize docosahexaenoic acid to epoxides, primarily 19R,20S-epoxyeicosapentaenoic acid and 19S,20R-epoxyeicosapentaenoic acid isomers (termed 19,20-EDP) and eicosapentaenoic acid to epoxides, primarily 17R,18S-eicosatetraenic acid and 17S,18R-eicosatetraenic acid isomers (termed 17,18-EEQ). 19-HETE is an inhibitor of 20-HETE, a broadly active signaling molecule, e.g. it constricts arterioles, elevates blood pressure, promotes inflammation responses, and stimulates the growth of various types of tumor cells; however the in vivo ability and significance of 19-HETE in inhibiting 20-HETE has not been demonstrated (see 20-Hydroxyeicosatetraenoic acid). The EDP (see Epoxydocosapentaenoic acid) and EEQ (see epoxyeicosatetraenoic acid) metabolites have a broad range of activities. In various animal models and in vitro studies on animal and human tissues, they decrease hypertension and pain perception; suppress inflammation; inhibit angiogenesis, endothelial cell migration and endothelial cell proliferation; and inhibit the growth and metastasis of human breast and prostate cancer cell lines. It is suggested that the EDP and EEQ metabolites function in humans as they do in animal models and that, as products of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid, the EDP and EEQ metabolites contribute to many of the beneficial effects attributed to dietary omega-3 fatty acids. EDP and EEQ metabolites are short-lived, being inactivated within seconds or minutes of formation by epoxide hydrolases, particularly soluble epoxide hydrolase, and therefore act locally. CYP2E1 is not regarded as being a major contributor to forming the cited epoxides but could act locally in certain tissues to do so.
## Substrates
Following is a table of selected substrates of CYP2E1. Where classes of agents are listed, there may be exceptions within the class.
# Structure
CYP2E1 exhibits structural motifs common to other human membrane-bound cytochrome P450 enzymes, and is composed of 12 major α-helices and 4 β-sheets with short intervening helices interspersed between the two. Like other enzymes of this class, the active site of CYP2E1 contains an iron atom bound by a heme center which mediates the electron transfer steps necessary to carry out oxidation of its substrates. The active site of CYP2E1 is the smallest observed in human P450 enzymes, with its small capacity attributed in part to the introduction of an isoleucine at position 115. The side-chain of this residue protrudes out above the heme center, restricting active site volume compared to related enzymes that have less bulky residues at this position. T303, which also protrudes into the active site, is particularly important for substrate positioning above the reactive iron center and is hence highly conserved by many cytochrome P450 enzymes. Its hydroxyl group is well-positioned to donate a hydrogen bond to potential acceptors on the substrate, and its methyl group has also been implicated in the positioning of fatty acids within the active site., A number of residues proximal to the active site including L368 help make up a constricted, hydrophobic access channel which may also be important for determining the enzyme's specificity towards small molecules and ω-1 hydroxylation of fatty acids.
# Regulation
## Genetic regulation
In humans, the CYP2E1 enzyme is encoded by the CYP2E1 gene. The enzyme has been identified in fetal liver, where it is posited to be the predominant ethanol-metabolizing enzyme, and may be connected to ethanol-mediated teratogenesis. In rats, within one day of birth the hepatic CYP2E1 gene is activated transcriptionally.
CYP2E1 expression is easily inducible, and can occur in the presence of a number of its substrates, including ethanol, isoniazid, tobacco, isopropanol, benzene, toluene, and acetone. For ethanol specifically, it seems that there exist two stages of induction, a post-translational mechanism for increased protein stability at low levels of ethanol and an additional transcriptional induction at high levels of ethanol.
## Chemical regulation
CYP2E1 is inhibited by a variety of small molecules, many of which act competitively. Two such inhibitors, indazole and 4-methylpyrazole, coordinate with the active site's iron atom and were crystallized with recombinant human CYP2E1 in 2008 to give the first true crystal structures of the enzyme. Other inhibitors include diethyldithiocarbamate (in cancer), and disulfiram (in alcoholism).
# Disease relevance
CYP2E1 is expressed in high levels in the liver, where it works to clear toxins from the body. In doing so, CYP2E1 bioactivates a variety of common anesthetics, including acetaminophen, halothane, enflurane, and isoflurane. The oxidation of these molecules by CYP2E1 can produce harmful substances such as trifluoroacetic acid chloride, and is a major reason for their observed hepatotoxicity in patients.
CYP2E1 and other cytochrome P450 enzymes can inadvertently produce reactive oxygen species (ROS) in their active site when catalysis is not coordinated correctly, resulting in potential lipid peroxidation as well as protein and DNA oxidation. CYP2E1 is particularly susceptible to this phenomenon compared to other P450 enzymes, suggesting that its expression levels may be important for negative physiological effects observed in a number of disease states.
CYP2E1 expression levels have been correlated with a variety of dietary and physiological factors, such as ethanol consumption, diabetes, fasting, and obesity. It appears that cellular levels of the enzyme may be controlled by the molecular chaperone HSP90, which upon association with CYP2E1 allows for transport to the proteasome and subsequent degradation. Ethanol and other substrates may disrupt this association, leading to the higher expression levels observed in their presence. The increased expression of CYP2E1 accompanying these health conditions may therefore contribute to their pathogenesis by increasing the rate of production of ROS in the body.
# Applications
Trees have been genetically engineered to overexpress the CYP2E1 enzyme. These transgenic trees have been used to remove pollutants from groundwater, a process known as phytoremediation. | CYP2E1
Cytochrome P450 2E1 (abbreviated CYP2E1, EC 1.14.13.n7) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. This class of enzymes is divided up into a number of subcategories, including CYP1, CYP2, and CYP3, which as a group are largely responsible for the breakdown of foreign compounds in mammals.[1]
The CYP2 subfamily is responsible for the majority of P450-mediated drug metabolism in humans.[1] While CYP2E1 itself carries out a relatively low number of these reactions (~4% of known P450-mediated drug oxidations), it and related enzymes CYP1A2 and CYP3A4 are responsible for the breakdown of a large number of toxic environmental chemicals and carcinogens that enter the body, in addition to basic metabolic reactions such as fatty acid oxidations.[2]
# Function
CYP2E1 is a membrane protein expressed in high levels in the liver, where it composes nearly 50% of the total hepatic cytochrome P450 mRNA[3] and 7% of the hepatic cytochrome P450 protein.[4] The liver is therefore where most drugs undergo deactivation by CYP2E1, either directly or by facilitated excretion from the body.
CYP2E1 metabolizes mostly small, polar molecules, including toxic laboratory chemicals such as dimethylformamide, aniline, and halogenated hydrocarbons (see table below). While these oxidations are often of benefit to the body, certain carcinogens and toxins are bioactivated by CYP2E1, implicating the enzyme in the onset of hepatotoxicity caused by certain classes of drugs (see disease relevance section below).
CYP2E1 also plays a role in several important metabolic reactions, including the conversion of ethanol to acetaldehyde and to acetate in humans,[5] where it works alongside alcohol dehydrogenase and aldehyde dehydrogenase. In the conversion sequence of acetyl-CoA to glucose, CYP2E1 transforms acetone via hydroxyacetone (acetol) into propylene glycol and methylglyoxal, the precursors of pyruvate, acetate and lactate.[6][7][8]
CYP2E1 also carries out the metabolism of endogenous fatty acids such as the ω-1 hydroxylation of fatty acids such as arachidonic acid, involving it in important signaling pathways that may link it to diabetes and obesity.[9] Thus, it acts as a monooxygenase to metabolize arachidonic acid to 19-hydroxyeicosatetraenoic acid (19-HETE) (see 20-Hydroxyeicosatetraenoic acid). However, it also acts as an epoxygenase activity to metabolize docosahexaenoic acid to epoxides, primarily 19R,20S-epoxyeicosapentaenoic acid and 19S,20R-epoxyeicosapentaenoic acid isomers (termed 19,20-EDP) and eicosapentaenoic acid to epoxides, primarily 17R,18S-eicosatetraenic acid and 17S,18R-eicosatetraenic acid isomers (termed 17,18-EEQ).[10] 19-HETE is an inhibitor of 20-HETE, a broadly active signaling molecule, e.g. it constricts arterioles, elevates blood pressure, promotes inflammation responses, and stimulates the growth of various types of tumor cells; however the in vivo ability and significance of 19-HETE in inhibiting 20-HETE has not been demonstrated (see 20-Hydroxyeicosatetraenoic acid). The EDP (see Epoxydocosapentaenoic acid) and EEQ (see epoxyeicosatetraenoic acid) metabolites have a broad range of activities. In various animal models and in vitro studies on animal and human tissues, they decrease hypertension and pain perception; suppress inflammation; inhibit angiogenesis, endothelial cell migration and endothelial cell proliferation; and inhibit the growth and metastasis of human breast and prostate cancer cell lines.[11][12][13][14] It is suggested that the EDP and EEQ metabolites function in humans as they do in animal models and that, as products of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid, the EDP and EEQ metabolites contribute to many of the beneficial effects attributed to dietary omega-3 fatty acids.[11][14][15] EDP and EEQ metabolites are short-lived, being inactivated within seconds or minutes of formation by epoxide hydrolases, particularly soluble epoxide hydrolase, and therefore act locally. CYP2E1 is not regarded as being a major contributor to forming the cited epoxides[14] but could act locally in certain tissues to do so.
## Substrates
Following is a table of selected substrates of CYP2E1. Where classes of agents are listed, there may be exceptions within the class.
# Structure
CYP2E1 exhibits structural motifs common to other human membrane-bound cytochrome P450 enzymes, and is composed of 12 major α-helices and 4 β-sheets with short intervening helices interspersed between the two.[9] Like other enzymes of this class, the active site of CYP2E1 contains an iron atom bound by a heme center which mediates the electron transfer steps necessary to carry out oxidation of its substrates. The active site of CYP2E1 is the smallest observed in human P450 enzymes, with its small capacity attributed in part to the introduction of an isoleucine at position 115. The side-chain of this residue protrudes out above the heme center, restricting active site volume compared to related enzymes that have less bulky residues at this position.[9] T303, which also protrudes into the active site, is particularly important for substrate positioning above the reactive iron center and is hence highly conserved by many cytochrome P450 enzymes.[9] Its hydroxyl group is well-positioned to donate a hydrogen bond to potential acceptors on the substrate, and its methyl group has also been implicated in the positioning of fatty acids within the active site.[18],[19] A number of residues proximal to the active site including L368 help make up a constricted, hydrophobic access channel which may also be important for determining the enzyme's specificity towards small molecules and ω-1 hydroxylation of fatty acids.[9]
.
# Regulation
## Genetic regulation
In humans, the CYP2E1 enzyme is encoded by the CYP2E1 gene.[20] The enzyme has been identified in fetal liver, where it is posited to be the predominant ethanol-metabolizing enzyme, and may be connected to ethanol-mediated teratogenesis.[21] In rats, within one day of birth the hepatic CYP2E1 gene is activated transcriptionally.
CYP2E1 expression is easily inducible, and can occur in the presence of a number of its substrates, including ethanol,[17] isoniazid,[17] tobacco,[22] isopropanol,[2] benzene,[2] toluene,[2] and acetone.[2] For ethanol specifically, it seems that there exist two stages of induction, a post-translational mechanism for increased protein stability at low levels of ethanol and an additional transcriptional induction at high levels of ethanol.[23]
## Chemical regulation
CYP2E1 is inhibited by a variety of small molecules, many of which act competitively. Two such inhibitors, indazole and 4-methylpyrazole, coordinate with the active site's iron atom and were crystallized with recombinant human CYP2E1 in 2008 to give the first true crystal structures of the enzyme.[9] Other inhibitors include diethyldithiocarbamate[16] (in cancer), and disulfiram[17] (in alcoholism).
# Disease relevance
CYP2E1 is expressed in high levels in the liver, where it works to clear toxins from the body.[3][4] In doing so, CYP2E1 bioactivates a variety of common anesthetics, including acetaminophen, halothane, enflurane, and isoflurane.[2] The oxidation of these molecules by CYP2E1 can produce harmful substances such as trifluoroacetic acid chloride,[24] and is a major reason for their observed hepatotoxicity in patients.
CYP2E1 and other cytochrome P450 enzymes can inadvertently produce reactive oxygen species (ROS) in their active site when catalysis is not coordinated correctly, resulting in potential lipid peroxidation as well as protein and DNA oxidation.[9] CYP2E1 is particularly susceptible to this phenomenon compared to other P450 enzymes, suggesting that its expression levels may be important for negative physiological effects observed in a number of disease states.[9]
CYP2E1 expression levels have been correlated with a variety of dietary and physiological factors, such as ethanol consumption,[25] diabetes,[26] fasting,[27] and obesity.[28] It appears that cellular levels of the enzyme may be controlled by the molecular chaperone HSP90, which upon association with CYP2E1 allows for transport to the proteasome and subsequent degradation. Ethanol and other substrates may disrupt this association, leading to the higher expression levels observed in their presence.[29] The increased expression of CYP2E1 accompanying these health conditions may therefore contribute to their pathogenesis by increasing the rate of production of ROS in the body.[9]
# Applications
Trees have been genetically engineered to overexpress the CYP2E1 enzyme. These transgenic trees have been used to remove pollutants from groundwater, a process known as phytoremediation.[30] | https://www.wikidoc.org/index.php/CYP2E1 | |
628488dcc52d9fcac4f4ff94eecd79e3d491c012 | wikidoc | CYP2J2 | CYP2J2
Cytochrome P450 2J2 (CYP2J2) is a protein that in humans is encoded by the CYP2J2 gene. CYP2J2 is a member of the cytochrome P450 superfamily of enzymes. The enzymes are oxygenases which catalyze many reactions involved in the metabolism of drugs and other xenobiotics) as well as in the synthesis of cholesterol, steroids and other lipids.
# Protein structure
The CYP2J2 contains the following domains:
- Hydrophobic binding domains
- F-G loop (containing non-conservative mutations) primary membrane binding motif
The protein also contains an N-terminal anchor.
## F-G loop
The F-G loop mediates the binding and passage of substrates, and its hydrophobic region containing residues Trp-235, Phe-239 and Ille-236 allows the enzyme to interact with cellular membranes. Mutations to hydrophilic residues in the F-G loop alter the binding mechanism by changing insertion depth of the enzyme into the membrane.
# Tissue distribution
CYP2J2 is expressed predominately in the heart and, to a lesser extent, in other tissues such as the liver, gastrointestinal tract, pancreas, lung, and central nervous system.
# Function
CYP2J2 localizes to the endoplasmic reticulum and is thought to be a prominent enzyme responsible for metabolizing endogenous polyunsaturated fatty acids to signaling molecules. It metabolizes arachidonic acid to the following eicosatrienoic acid epoxides (termed EETs): 5,6-epoxy-8Z,11Z,14Z-EET, 8,9-epoxy-8Z,11Z,14Z-EET, 11,12-epoxy-5Z,8Z,14Z-EET, and 14,15-epoxy-5Z,8Z,11Z-EET. CYP2J2 also metabolizes linoleic acid to 9,10-epoxy octadecaenoic acids (also termed vernolic acid, linoleic acid 9:10-oxide, or leukotoxin) and 12,13-epoxy-octadecaenoic (also termed coronaric acid, linoleic acid 12,13-oxide, or isoleukotoxin); docosahexaenoic acid to various epoxydocosapentaenoic acids (also termed EDPs); and eicosapentaenoic acid to various epoxyeicosatetraenoic acids (also termed EEQs).
CYP2J2, along with CYP219, CYP2C8, CYP2C9, and possibly CYP2S1 are the main producers of EETs and, very likely EEQs, EDPs, and the epoxides of linoleic acid.
# Animal studies
Animal model studies implicate the EETs, EDPs, and EEQs in regulating hypertension, the development of myocardial infarction and other damage to the heart, the growth of various cancers, inflammation, blood vessel formation, and pain perception; limited studies suggest but have not proven that these epoxides may function similarly in humans (see epoxyeicosatrienoic acid, epoxydocosapentaenoic acid, and epoxygenase pages). Vernolic and coronaric acids are potentially toxic, causing multiple organ failure and respiratory distress when injected into animals.
# Human studies
Tissue samples containing carcinomas were obtained from 130 subjects and analyzed for expression of CYP2J2. Increased detection of CYP2J2 mRNA and protein were evident in 77% of patient carcinoma cell lines. Cell proliferation was positively regulated by CYP2J2 and furthermore CYP2J2 was shown to promote tumor progression. There was also a greater amount of CYP2J2 mRNA in various tumor types, including esophageal adenocarcinoma, breast carcinoma, and stomach carcinoma compared to that of surrounding normal tissue.
The overexpression of CYP2J2 and its effects on carcinoma cells are also evident when EETs are administered exogenously, suggesting a link between the production of EETs and cancer progression. Furthermore, tumor progression increases at a faster rate in cell lines with over-expression of CYP2J2 compared to control cancer cell lines.
# Clinical significance
CYP2J2 is over-expressed in a number of cancers, and forced over-expression of CYP2J2 in human cancer cells lines accelerates proliferation and protects cells against apoptosis.
HETEs and EETs derived from CYP2J2 have also been shown to contribute to the proper functioning of the cardiovascular system and the regulation of the renal and pulmonary systems in humans. CYP2J2 is readily expressed in the cardiac myocytes and endothelial cells of the coronary artery where various EETs are produced. The presence of EETs relaxes vascular smooth muscle cells by hyperpolarizing the cell membrane, thus highlighting the protective anti-inflammatory function of CYP2J2 in the circulatory system. There is still conflict in studies on the effects of EETs in relation to the cardiovascular system. P450 enzymes have shown both positive and negative effects in the heart, and the production of EETs has been shown to produce vascular protective and vascular depressive mechanisms. The over-expression of CYP2J2 enhances the activation of mitoKATP, and is believed to confer a physiological benefit by altering the production of reactive oxygen species. | CYP2J2
Cytochrome P450 2J2 (CYP2J2) is a protein that in humans is encoded by the CYP2J2 gene.[1][2] CYP2J2 is a member of the cytochrome P450 superfamily of enzymes. The enzymes are oxygenases which catalyze many reactions involved in the metabolism of drugs and other xenobiotics) as well as in the synthesis of cholesterol, steroids and other lipids.
# Protein structure
The CYP2J2 contains the following domains:[3]
• Hydrophobic binding domains
• F-G loop (containing non-conservative mutations) primary membrane binding motif
The protein also contains an N-terminal anchor.
## F-G loop
The F-G loop mediates the binding and passage of substrates, and its hydrophobic region containing residues Trp-235, Phe-239 and Ille-236 allows the enzyme to interact with cellular membranes. Mutations to hydrophilic residues in the F-G loop alter the binding mechanism by changing insertion depth of the enzyme into the membrane.
# Tissue distribution
CYP2J2 is expressed predominately in the heart and, to a lesser extent, in other tissues such as the liver, gastrointestinal tract, pancreas, lung, and central nervous system.[4]
# Function
CYP2J2 localizes to the endoplasmic reticulum and is thought to be a prominent enzyme responsible for metabolizing endogenous polyunsaturated fatty acids to signaling molecules.[5] It metabolizes arachidonic acid to the following eicosatrienoic acid epoxides (termed EETs): 5,6-epoxy-8Z,11Z,14Z-EET, 8,9-epoxy-8Z,11Z,14Z-EET, 11,12-epoxy-5Z,8Z,14Z-EET, and 14,15-epoxy-5Z,8Z,11Z-EET. CYP2J2 also metabolizes linoleic acid to 9,10-epoxy octadecaenoic acids (also termed vernolic acid, linoleic acid 9:10-oxide, or leukotoxin) and 12,13-epoxy-octadecaenoic (also termed coronaric acid, linoleic acid 12,13-oxide, or isoleukotoxin); docosahexaenoic acid to various epoxydocosapentaenoic acids (also termed EDPs); and eicosapentaenoic acid to various epoxyeicosatetraenoic acids (also termed EEQs).[6]
CYP2J2, along with CYP219, CYP2C8, CYP2C9, and possibly CYP2S1 are the main producers of EETs and, very likely EEQs, EDPs, and the epoxides of linoleic acid.[7][8]
# Animal studies
Animal model studies implicate the EETs, EDPs, and EEQs in regulating hypertension, the development of myocardial infarction and other damage to the heart, the growth of various cancers, inflammation, blood vessel formation, and pain perception; limited studies suggest but have not proven that these epoxides may function similarly in humans (see epoxyeicosatrienoic acid, epoxydocosapentaenoic acid, and epoxygenase pages).[8] Vernolic and coronaric acids are potentially toxic, causing multiple organ failure and respiratory distress when injected into animals.[8]
# Human studies
Tissue samples containing carcinomas were obtained from 130 subjects and analyzed for expression of CYP2J2. Increased detection of CYP2J2 mRNA and protein were evident in 77% of patient carcinoma cell lines. Cell proliferation was positively regulated by CYP2J2 and furthermore CYP2J2 was shown to promote tumor progression.[9] There was also a greater amount of CYP2J2 mRNA in various tumor types, including esophageal adenocarcinoma, breast carcinoma, and stomach carcinoma compared to that of surrounding normal tissue.
The overexpression of CYP2J2 and its effects on carcinoma cells are also evident when EETs are administered exogenously, suggesting a link between the production of EETs and cancer progression. Furthermore, tumor progression increases at a faster rate in cell lines with over-expression of CYP2J2 compared to control cancer cell lines.[9]
# Clinical significance
CYP2J2 is over-expressed in a number of cancers, and forced over-expression of CYP2J2 in human cancer cells lines accelerates proliferation and protects cells against apoptosis.[4]
HETEs and EETs derived from CYP2J2 have also been shown to contribute to the proper functioning of the cardiovascular system and the regulation of the renal and pulmonary systems in humans.[citation needed] CYP2J2 is readily expressed in the cardiac myocytes and endothelial cells of the coronary artery where various EETs are produced. The presence of EETs relaxes vascular smooth muscle cells by hyperpolarizing the cell membrane, thus highlighting the protective anti-inflammatory function of CYP2J2 in the circulatory system.[4] There is still conflict in studies on the effects of EETs in relation to the cardiovascular system.[10][11] P450 enzymes have shown both positive and negative effects in the heart, and the production of EETs has been shown to produce vascular protective and vascular depressive mechanisms.[4] The over-expression of CYP2J2 enhances the activation of mitoKATP, and is believed to confer a physiological benefit by altering the production of reactive oxygen species.[4] | https://www.wikidoc.org/index.php/CYP2J2 | |
ba80882847b12c7019dcb84b0dded27e155bf0d7 | wikidoc | CYP2R1 | CYP2R1
Vitamin D 25-hydroxylase also known as cytochrome P450 2R1 is an enzyme that in humans is encoded by the CYP2R1 gene.
# Function
Vitamin D 25-hydroxylase is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. Found in the liver, this enzyme is a microsomal vitamin D hydroxylase that converts vitamin D into 25-hydroxyvitamin D (calcidiol), which is the major circulatory form of the vitamin.
# Clinical significance
An inherited mutation in the CYP2R1 gene which results in the substitution of a proline for a leucine residue at codon 99 eliminates the enzyme activity and is associated with low circulating levels of 25-hydroxyvitamin D and classic symptoms of vitamin D deficiency. The gene product which it encodes, vitamin D 25-hydroxylase, has therefore been proposed as the key enzyme in the conversion of cholecalciferol (vitamin D3) to calcidiol. Calcidiol is subsequently converted by the action of 25-hydroxyvitamin D3 1-alpha-hydroxylase to calcitriol, the active form of vitamin D3 that binds to the vitamin D receptor (VDR) which mediates most of the physiological actions of the vitamin.
## Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.
- ↑ The interactive pathway map can be edited at WikiPathways: "VitaminDSynthesis_WP1531"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
# Model organisms
Model organisms have been used in the study of CYP2R1 function. A conditional knockout mouse line called Cyp2r1tm1b(EUCOMM)Wtsi was generated at the Wellcome Trust Sanger Institute. Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Additional screens performed: - In-depth immunological phenotyping | CYP2R1
Vitamin D 25-hydroxylase also known as cytochrome P450 2R1 is an enzyme that in humans is encoded by the CYP2R1 gene.[1][2][3]
# Function
Vitamin D 25-hydroxylase is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. Found in the liver, this enzyme is a microsomal vitamin D hydroxylase that converts vitamin D into 25-hydroxyvitamin D (calcidiol), which is the major circulatory form of the vitamin.
# Clinical significance
An inherited mutation in the CYP2R1 gene which results in the substitution of a proline for a leucine residue at codon 99 eliminates the enzyme activity and is associated with low circulating levels of 25-hydroxyvitamin D and classic symptoms of vitamin D deficiency.[2] The gene product which it encodes, vitamin D 25-hydroxylase, has therefore been proposed as the key enzyme in the conversion of cholecalciferol (vitamin D3) to calcidiol. Calcidiol is subsequently converted by the action of 25-hydroxyvitamin D3 1-alpha-hydroxylase to calcitriol, the active form of vitamin D3 that binds to the vitamin D receptor (VDR) which mediates most of the physiological actions of the vitamin.[2]
## Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- ↑ The interactive pathway map can be edited at WikiPathways: "VitaminDSynthesis_WP1531"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
# Model organisms
Model organisms have been used in the study of CYP2R1 function. A conditional knockout mouse line called Cyp2r1tm1b(EUCOMM)Wtsi was generated at the Wellcome Trust Sanger Institute.[4] Male and female animals underwent a standardized phenotypic screen[5] to determine the effects of deletion.[6][7][8][9] Additional screens performed: - In-depth immunological phenotyping[10] | https://www.wikidoc.org/index.php/CYP2R1 | |
08a2b5fceb4ac3468625f31cc55a91a46a527c72 | wikidoc | CYP2S1 | CYP2S1
Cytochrome P450 2S1 is a protein that in humans is encoded by the CYP2S1 gene. The gene is located in chromosome 19q13.2 within a cluster including other CYP2 family members such as CYP2A6, CYP2A13, CYP2B6, and CYP2F1.
# Expression
CYP2S1 is highly expressed in epithelial tissues of the respiratory, gastrointestinal, urinary tracts, and skin and in leukocytes of the monocyte/macrophage and lymphocyte series; it is also expressed throughout Embryogenesis and, as discussed below, certain types of cancers.
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum. In rodents, the homologous protein has been shown to metabolize certain carcinogens although its specific function(s) in humans has not been clearly determined. In in vitro studies, the human enzyme has been found to metabolize all-trans-retinoic acid to 4-hydroxy-retinoic acid and 5, 6-epoxy-retinoic acid and therefore may play a role in processing retinoic acid in tissues where it is highly expressed such as the skin. CYP2S1 is significantly overexpressed and, perhaps directly related to this, its gene is significantly hypometylated (see gene methylation in the skin of Han Chinese patients with psoriasis suggesting that it plays a role in the development of this disease.
CYP2S1 has been suggested to be involved in the growth and/or spread of certain tumors of epithelial cell origin: its higher expression in breast or colorectal cancer tissues appears associated respectively with shorter survival times or poor prognoses, and it is more highly expressed in metastasis compared to primary tumor tissues of ovarian cancer.
CYP2S1 has recently been assigned epoxygenase activity. It metabolizes 1) arachidonic acid to its various epoxides, i.e., the epoxyeicosatrienoic acids (also termed EETs); 2) docosahexaenoic acid to its various epoxides, i.e. the epoxydocosapentaenoic acids (also termed EDPs); and 3) linoleic acid to its various epoxides, i.e. vernolic acid (also termed leukotoxin) and coronaric acid (also termed isoleukotoxin). It seems likely, although not yet tested, that CYP231 will also prove able to metabolize other polyunsaturated fatty acids to their epoxides; for example, the enzyme may metabolize eicosapentaenoic acid to epoxyeicosatetraenoic acids (also termed EEQs). Animal model studies implicate the EET, EDP, and EEQ epoxides in regulating blood pressure, tissue blood flow, new blood vessel formation (i.e. angiogenesis, pain perception, and the growth of various cancers; limited studies suggest but have not proven that these epoxides may function similarly in humans (see epoxyeicosatrienoic acid, epoxydocosapentaenoic acid, eicosatetraenoic acid, and epoxygenase pages). The CYP2S1-dependent production of EETs, which stimulate the growth of various types of cancer cells, including those of he colon (see epoxyeicosatrienoic acid#cancer), could contribute to the unfavorable effects of this CYP in the sited cancers.
Vernolic and coronaric acids are potentially toxic, causing multiple organ failure and acute respiratory distress when injected into animals and suggested to be involved in causing these syndromes in humans.
CYP2S1 has also been found to metabolize Prostaglandin G2 and Prostaglandin H2 to the biologically active product, 12-Hydroxyheptadecatrienoic acid (i.e. 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid, also termed 12-HHT). | CYP2S1
Cytochrome P450 2S1 is a protein that in humans is encoded by the CYP2S1 gene.[1][2] The gene is located in chromosome 19q13.2 within a cluster including other CYP2 family members such as CYP2A6, CYP2A13, CYP2B6, and CYP2F1.[3]
# Expression
CYP2S1 is highly expressed in epithelial tissues of the respiratory, gastrointestinal, urinary tracts, and skin and in leukocytes of the monocyte/macrophage and lymphocyte series; it is also expressed throughout Embryogenesis and, as discussed below, certain types of cancers.[3]
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum. In rodents, the homologous protein has been shown to metabolize certain carcinogens although its specific function(s) in humans has not been clearly determined.[2] In in vitro studies, the human enzyme has been found to metabolize all-trans-retinoic acid to 4-hydroxy-retinoic acid and 5, 6-epoxy-retinoic acid and therefore may play a role in processing retinoic acid in tissues where it is highly expressed such as the skin.[3] CYP2S1 is significantly overexpressed and, perhaps directly related to this, its gene is significantly hypometylated (see gene methylation in the skin of Han Chinese patients with psoriasis suggesting that it plays a role in the development of this disease.[4]
CYP2S1 has been suggested to be involved in the growth and/or spread of certain tumors of epithelial cell origin: its higher expression in breast or colorectal cancer tissues appears associated respectively with shorter survival times or poor prognoses, and it is more highly expressed in metastasis compared to primary tumor tissues of ovarian cancer.[3][5][6][7]
CYP2S1 has recently been assigned epoxygenase activity. It metabolizes 1) arachidonic acid to its various epoxides, i.e., the epoxyeicosatrienoic acids (also termed EETs); 2) docosahexaenoic acid to its various epoxides, i.e. the epoxydocosapentaenoic acids (also termed EDPs); and 3) linoleic acid to its various epoxides, i.e. vernolic acid (also termed leukotoxin) and coronaric acid (also termed isoleukotoxin).[8] It seems likely, although not yet tested, that CYP231 will also prove able to metabolize other polyunsaturated fatty acids to their epoxides; for example, the enzyme may metabolize eicosapentaenoic acid to epoxyeicosatetraenoic acids (also termed EEQs). Animal model studies implicate the EET, EDP, and EEQ epoxides in regulating blood pressure, tissue blood flow, new blood vessel formation (i.e. angiogenesis, pain perception, and the growth of various cancers; limited studies suggest but have not proven that these epoxides may function similarly in humans (see epoxyeicosatrienoic acid, epoxydocosapentaenoic acid, eicosatetraenoic acid, and epoxygenase pages).[9] The CYP2S1-dependent production of EETs, which stimulate the growth of various types of cancer cells, including those of he colon (see epoxyeicosatrienoic acid#cancer), could contribute to the unfavorable effects of this CYP in the sited cancers.
Vernolic and coronaric acids are potentially toxic, causing multiple organ failure and acute respiratory distress when injected into animals and suggested to be involved in causing these syndromes in humans.[9]
CYP2S1 has also been found to metabolize Prostaglandin G2 and Prostaglandin H2 to the biologically active product, 12-Hydroxyheptadecatrienoic acid (i.e. 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid, also termed 12-HHT).[8] | https://www.wikidoc.org/index.php/CYP2S1 | |
c1a9f8333ff8cc547eae75611a7f6a51c0963c24 | wikidoc | CYP2U1 | CYP2U1
CYP2U1 (cytochrome P450, family 2, subfamily U, polypeptide 1) is a protein that in humans is encoded by the CYP2U1 gene
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and the hydroxylation of fatty acids and fatty acid metabolites. CYP2U1 metabolized arachidonic acid, docosahexaenoic acid (DHA), and other long chain fatty acids which suggests that CYP2U1 may play a role in brain and immune functions. CYP2U1 also metabolizes propanone, acetone, and 2-oxypropane.
# Tissue distribution
The CYP2U1 gene is a highly conserved gene that is mainly expressed in brain and thymus, but also at lower levels in kidney, lung, and heart.
# Reactions
CYP2U1 hydroxylates arachidonic acid, docosahexaenoic acid (DHA), and other long chain fatty acids at their terminal (i.e., ω) carbon to form 20-hydroxy-arachidonic acid (i.e. 20-Hydroxyeicosatetraenoic acid or 20-HETE), 22-hydroxy-docosahexaneoic acid, and other ω-hydroxy long chain fatty acids, respectively, plus lesser amounts of these fatty acids ω-1 hydroxy metabolites, i.e. 19-HETE, 21-hydroxy-docosahexaenoic acid, and other ω-1 hydroxy long chain fatty acids, respectively. One of these metabolites, 20-HETE, is a regulator of blood pressure and blood flow to organs in animal models and, based on genetic studies, possibly in humans (see20-Hydroxyeicosatetraenoic acid).
# Clinical significance
A mutation (c.947A>T) in CYP2U1 has been associated in a very small number of patients with Hereditary spastic paraplegia in that it segregates with the disease at the homozygous state in two afflicted families. This mutation affects an amino acid (p.Asp316Val) that is highly conserved among CYP2U1 orthologs as well as other cytochrome P450 proteins; this p.Asp314Val mutation is located in the enzyme's functional domain, is predicted to be damaging to the enzyme's activity, and is associated with mitochondria dysfunction. A second homozygous enzyme-disabling mutation has been identified in CYP2U1, c.1A>C/p.Met1?, that is associated with <1% of hereditary spastic paraplegia sufferers. The reduction in 20-HETE production by these mutations, and thereby in 20-HETE's activation of the TRPV1 neural receptor, it is hypothesized, may contribute to the development of this disease (see 20-Hydroxyeicosatetraenoic acid for details).
CYPU21 along with members of the CYP4A and CYP4F sub-families also ω-hydroxylate and thereby reduce the activity of various fatty acid metabolites of arachidonic acid including LTB4, 5-HETE, 5-oxo-eicosatetraenoic acid, 12-HETE, and several prostaglandins that are involved in regulating various inflammatory, vascular, and other responses in animals and humans. This hydroxylation-induced inactivation may underlie the proposed roles of the cytochromes in dampening inflammatory responses and the reported associations of certain CYP4F2 and CYP4F3 single nucleotide variants with human Krohn's disease and Coeliac disease, respectively. | CYP2U1
CYP2U1 (cytochrome P450, family 2, subfamily U, polypeptide 1) is a protein that in humans is encoded by the CYP2U1 gene[1]
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and the hydroxylation of fatty acids and fatty acid metabolites.[2] CYP2U1 metabolized arachidonic acid, docosahexaenoic acid (DHA), and other long chain fatty acids which suggests that CYP2U1 may play a role in brain and immune functions.[1] CYP2U1 also metabolizes propanone, acetone, and 2-oxypropane.
# Tissue distribution
The CYP2U1 gene is a highly conserved gene that is mainly expressed in brain and thymus, but also at lower levels in kidney, lung, and heart.[3]
# Reactions
CYP2U1 hydroxylates arachidonic acid, docosahexaenoic acid (DHA), and other long chain fatty acids at their terminal (i.e., ω) carbon to form 20-hydroxy-arachidonic acid (i.e. 20-Hydroxyeicosatetraenoic acid or 20-HETE), 22-hydroxy-docosahexaneoic acid, and other ω-hydroxy long chain fatty acids, respectively, plus lesser amounts of these fatty acids ω-1 hydroxy metabolites, i.e. 19-HETE, 21-hydroxy-docosahexaenoic acid, and other ω-1 hydroxy long chain fatty acids, respectively.[1] One of these metabolites, 20-HETE, is a regulator of blood pressure and blood flow to organs in animal models and, based on genetic studies, possibly in humans (see20-Hydroxyeicosatetraenoic acid).
# Clinical significance
A mutation (c.947A>T) in CYP2U1 has been associated in a very small number of patients with Hereditary spastic paraplegia in that it segregates with the disease at the homozygous state in two afflicted families. This mutation affects an amino acid (p.Asp316Val) that is highly conserved among CYP2U1 orthologs as well as other cytochrome P450 proteins; this p.Asp314Val mutation is located in the enzyme's functional domain, is predicted to be damaging to the enzyme's activity, and is associated with mitochondria dysfunction.[4][5] A second homozygous enzyme-disabling mutation has been identified in CYP2U1, c.1A>C/p.Met1?, that is associated with <1% of hereditary spastic paraplegia sufferers.[6] The reduction in 20-HETE production by these mutations, and thereby in 20-HETE's activation of the TRPV1 neural receptor, it is hypothesized, may contribute to the development of this disease (see 20-Hydroxyeicosatetraenoic acid for details).[4]
CYPU21 along with members of the CYP4A and CYP4F sub-families also ω-hydroxylate and thereby reduce the activity of various fatty acid metabolites of arachidonic acid including LTB4, 5-HETE, 5-oxo-eicosatetraenoic acid, 12-HETE, and several prostaglandins that are involved in regulating various inflammatory, vascular, and other responses in animals and humans.[7][8] This hydroxylation-induced inactivation may underlie the proposed roles of the cytochromes in dampening inflammatory responses and the reported associations of certain CYP4F2 and CYP4F3 single nucleotide variants with human Krohn's disease and Coeliac disease, respectively.[9][10][11] | https://www.wikidoc.org/index.php/CYP2U1 | |
496d2f0c4cd79c15e07995a758086e9788027458 | wikidoc | CYP3A4 | CYP3A4
Cytochrome P450 3A4 (abbreviated CYP3A4) (EC 1.14.13.97) is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from the body.
While many drugs are deactivated by CYP3A4, there are also some drugs which are activated by the enzyme. Some substances, such as grapefruit juice and some drugs, interfere with the action of CYP3A4. These substances will therefore either amplify or weaken the action of those drugs that are modified by CYP3A4.
CYP3A4 is a member of the cytochrome P450 family of oxidizing enzymes. Several other members of this family are also involved in drug metabolism, but CYP3A4 is the most common and the most versatile one. Like all members of this family, it is a hemoprotein, i.e. a protein containing a heme group with an iron atom. In humans, the CYP3A4 protein is encoded by the CYP3A4 gene. This gene is part of a cluster of cytochrome P450 genes on chromosome 7q22.1.
# Function
CYP3A4 is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids components.
The CYP3A4 protein localizes to the endoplasmic reticulum, and its expression is induced by glucocorticoids and some pharmacological agents. Cytochrome P450 enzymes metabolize approximately 60% of prescribed drugs, with CYP3A4 responsible for about half of this metabolism; substrates include acetaminophen, codeine, ciclosporin (cyclosporin), diazepam, and erythromycin. The enzyme also metabolizes some steroids and carcinogens. Most drugs undergo deactivation by CYP3A4, either directly or by facilitated excretion from the body. Also, many substances are bioactivated by CYP3A4 to form their active compounds, and many protoxins being toxicated into their toxic forms (for examples – see table below).
CYP3A4 also possesses epoxygenase activity in that it metabolizes arachidonic acid to epoxyeicosatrienoic acids (EETs), i.e. (±)-8,9-, (±)-11,12-, and (±)-14,15-epoxyeicosatrienoic acids. The EETs have a wide range of activities including the promotion of certain types of cancers (see epoxyeicosatetraenoic acid#cancer). CYP3A4 promotes the growth of various types of human cancer cell lines in culture by producing (±)-14,15-epoxyeicosatrienoic acids which stimulate these cells to grow. The cytochrome P450 is also reported to have fatty acid monooxgenase activity for metabolizing arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE). 20-HETE has a wide range of activities that also include growth stimulation in breast and other types of cancers (see 12-hydroxyeicosatetraenoic acid#cancer).
# Evolution
The CYP3A4 gene exhibits a much more complicated upstream regulatory region in comparison with its paralogs. This increased complexity renders the CYP3A4 gene more sensitive to endogenous and exogenous PXR and CAR ligands, instead of relying on gene variants for wider specificity. Chimpanzee and human CYP3A4 are highly conserved in metabolism of many ligands, although four amino acids positively selected in humans led to a 5-fold benzylation of 7-BFC in the presence of the hepatotoxic secondary bile acid lithocholic acid. This change in consequence contributes to an increased human defense against cholestasis.
# Tissue distribution
Fetuses do not really express CYP3A4 in their liver tissue, but rather CYP3A7 (EC 1.14.14.1), which acts on a similar range of substrates. CYP3A4 is absent in fetal liver but increases to approximately 40% of adult levels in the fourth month of life and 72% at 12 months.
Although CYP3A4 is predominantly found in the liver, it is also present in other organs and tissues of the body, where it may play an important role in metabolism. CYP3A4 in the intestine plays an important role in the metabolism of certain drugs. Often this allows prodrugs to be activated and absorbed – as in the case of the histamine H1-receptor antagonist terfenadine.
Recently CYP3A4 has also been identified in the brain, however its role in the central nervous system is still unknown.
# Mechanisms
Cytochrome P450 enzymes perform an assortment of modifications on a variety of ligands, utilizing its large active site and its ability to bind more than one substrate at a time to perform complicated chemical alterations in the metabolism of endogenous and exogenous compounds. These include hydroxylation, epoxidation of olefins, aromatic oxidation, heteroatom oxidations, N- and O- dealkylation reactions, aldehyde oxidations, dehydrogenation reactions, and aromatase activity.
Hydroxylation of an sp3 C-H bond is one of the ways in which CYP3A4 (and cytochrome P450 oxygenases) affects its ligand. In fact, hydroxylation is sometimes followed by dehydrogenation, leading to more complex metabolites. An example of a molecule that undergoes more than one reaction due to CYP3A4 includes tamoxifen, which is hydroxylated to 4-hydroxy-tamoxifen and then dehydrated to 4-hydroxy-tamoxifen quinone methide. Two mechanisms have been proposed as the primary pathway of hydroxylation in P450 enzymes.
The first pathway suggested is a cage-controlled radical method ("oxygen rebound"), and the second involves a concerted mechanism that does not utilize a radical intermediate but instead acts very quickly via a "radical clock".
# Inhibition through fruit ingestion
In 1998, various researchers showed that grapefruit juice, and grapefruit in general, is a potent inhibitor of CYP3A4, which can affect the metabolism of a variety of drugs, increasing their bioavailability. In some cases, this can lead to a fatal interaction with drugs like astemizole or terfenadine. The effect of grapefruit juice with regard to drug absorption was originally discovered in 1989. The first published report on grapefruit drug interactions was in 1991 in the Lancet entitled "Interactions of Citrus Juices with Felodipine and Nifedipine", and was the first reported food-drug interaction clinically. The effects of grapefruit last from 3–7 days, with the greatest effects when juice is taken an hour previous to administration of the drug.
In addition to grapefruit, other fruits have similar effects. Noni (M. citrifolia), for example, is a dietary supplement typically consumed as a juice and also inhibits CYP3A4; pomegranate juice has this effect as well.
# Variability
While over 28 single nucleotide polymorphisms (SNPs) have been identified in the CYP3A4 gene, it has been found that this does not translate into significant interindividual variability in vivo. It can be supposed that this may be due to the induction of CYP3A4 on exposure to substrates.
CYP3A4 alleles which have been reported to have minimal function compared to wild-type include CYP3A4*6 (an A17776 insertion) and CYP3A4*17 (F189S). Both of these SNPs led to decreased catalytic activity with certain ligands, including testosterone and nifedipine in comparison to wild-type metabolism.
Variability in CYP3A4 function can be determined noninvasively by the erythromycin breath test (ERMBT). The ERMBT estimates in vivo CYP3A4 activity by measuring the radiolabelled carbon dioxide exhaled after an intravenous dose of (14C-N-methyl)-erythromycin.
# Induction
CYP3A4 is induced by a wide variety of ligands. These ligands bind to the pregnane X receptor (PXR). The activated PXR complex forms a heterodimer with the retinoid X receptor (RXR), which binds to the XREM region of the CYP3A4 gene. XREM is a regulatory region of the CYP3A4 gene, and binding causes a cooperative interaction with proximal promoter regions of the gene, resulting in increased transcription and expression of CYP3A4. Activation of the PXR/RXR heterodimer initiates transcription of the CYP3A4 promoter region and gene. Ligand binding increases when in the presence of CYP3A4 ligands, such as in the presence of aflatoxin B1, M1, and G1. Indeed, due to the enzyme's large and malleable active site, it is possible for the enzyme to bind multiple ligands at once, leading to potentially detrimental side effects.
Induction of CYP3A4 has been shown to vary in humans depending on sex. Evidence shows an increased drug clearance by CYP3A4 in women, even when accounting for differences in body weight. A study by Wolbold et al. (2003) found that the median CYP3A4 levels measured from surgically removed liver samples of a random sample of women exceeded CYP3A4 levels in the livers of men by 129%. CYP3A4 mRNA transcripts were found in similar proportions, suggesting a pre-translational mechanism for the up-regulation of CYP3A4 in women. The exact cause of this elevated level of enzyme in women is still under speculation, however studies have elucidated other mechanisms (such as CYP3A5 or CYP3A7 compensation for lowered levels of CYP3A4) that affect drug clearance in both men and women.
CYP3A4 substrate activation varies amongst different animal species. Certain ligands activate human PXR, which promotes CYP3A4 transcription, while showing no activation in other species. For instance, mouse PXR is not activated by rifampicin and human PXR is not activated by pregnenalone 16α-carbonitrile In order to facilitate study of CYP3A4 functional pathways in vivo, mouse strains have been developed using transgenes in order to produce null/human CYP3A4 and PXR crosses. Although humanized hCYP3A4 mice successfully expressed the enzyme in their intestinal tract, low levels of hCYP3A4 were found in the liver. This effect has been attributed to CYP3A4 regulation by the growth hormone signal transduction pathway. In addition to providing an in vivo model, humanized CYP3A4 mice (hCYP3A4) have been used to further emphasize gender differences in CYP3A4 activity.
CYP3A4 activity levels have also been linked to diet and environmental factors, such as duration of exposure to xenobiotic substances. Due to the enzyme's extensive presence in the intestinal mucosa, the enzyme has shown sensitivity to starvation symptoms and is upregulated in defense of adverse effects. Indeed, in fatheaded minnows, unfed female fish were shown to have increased PXR and CYP3A4 expression, and displayed a more pronounced response to xenobiotic factors after exposure after several days of starvation. By studying animal models and keeping in mind the innate differences in CYP3A4 activation, investigators can better predict drug metabolism and side effects in human CYP3A4 pathways.
# Turnover
Estimates of the turnover rate of human CYP3A4 vary widely. For hepatic CYP3A4, in vivo methods yield estimates of enzyme half-life mainly in the range of 70 to 140 hours, whereas in vitro methods give estimates from 26 to 79 hours. Turnover of gut CYP3A4 is likely to be a function of the rate of enterocyte renewal; an indirect approach based on recovery of activity following exposure to grapefruit juice yields measurements in the 12- to 33-hour range.
# Technology
Due to membrane-bound CYP3A4's natural propensity to conglomerate, it has historically been difficult to study drug binding in both solution and on surfaces. Co-crystallization is difficult since the substrates tend to have a low Kd (between 5-150 μM) and low solubility in aqueous solutions. A successful strategy in isolating the bound enzyme is the functional stabilization of monomeric CYP3A4 on silver nanoparticles produced from nanosphere lithography and analyzed via localized surface plasmon resonance spectroscopy (LSPR). These analyses can be used as a high-sensitivity assay of drug binding, and may become integral in further high-throughput assays utilized in initial drug discovery testing. In addition to LSPR, CYP3A4-Nanodisc complexes have been found helpful in other applications including solid-state NMR, redox potentiometry, and steady-state enzyme kinetics.
# CYP3A4 ligands
Following is a table of selected substrates, inducers and inhibitors of CYP3A4. Where classes of agents are listed, there may be exceptions within the class.
Inhibitors of CYP3A4 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.
- ↑ The interactive pathway map can be edited at WikiPathways: "IrinotecanPathway_WP46359"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | CYP3A4
Cytochrome P450 3A4 (abbreviated CYP3A4) (EC 1.14.13.97) is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from the body.
While many drugs are deactivated by CYP3A4, there are also some drugs which are activated by the enzyme. Some substances, such as grapefruit juice and some drugs, interfere with the action of CYP3A4. These substances will therefore either amplify or weaken the action of those drugs that are modified by CYP3A4.
CYP3A4 is a member of the cytochrome P450 family of oxidizing enzymes. Several other members of this family are also involved in drug metabolism, but CYP3A4 is the most common and the most versatile one. Like all members of this family, it is a hemoprotein, i.e. a protein containing a heme group with an iron atom. In humans, the CYP3A4 protein is encoded by the CYP3A4 gene.[1] This gene is part of a cluster of cytochrome P450 genes on chromosome 7q22.1.[2]
# Function
CYP3A4 is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids components.
The CYP3A4 protein localizes to the endoplasmic reticulum, and its expression is induced by glucocorticoids and some pharmacological agents. Cytochrome P450 enzymes metabolize approximately 60% of prescribed drugs, with CYP3A4 responsible for about half of this metabolism;[3] substrates include acetaminophen, codeine, ciclosporin (cyclosporin), diazepam, and erythromycin. The enzyme also metabolizes some steroids and carcinogens.[4] Most drugs undergo deactivation by CYP3A4, either directly or by facilitated excretion from the body. Also, many substances are bioactivated by CYP3A4 to form their active compounds, and many protoxins being toxicated into their toxic forms (for examples – see table below).
CYP3A4 also possesses epoxygenase activity in that it metabolizes arachidonic acid to epoxyeicosatrienoic acids (EETs), i.e. (±)-8,9-, (±)-11,12-, and (±)-14,15-epoxyeicosatrienoic acids.[5] The EETs have a wide range of activities including the promotion of certain types of cancers (see epoxyeicosatetraenoic acid#cancer). CYP3A4 promotes the growth of various types of human cancer cell lines in culture by producing (±)-14,15-epoxyeicosatrienoic acids which stimulate these cells to grow.[6] The cytochrome P450 is also reported to have fatty acid monooxgenase activity for metabolizing arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE).[7] 20-HETE has a wide range of activities that also include growth stimulation in breast and other types of cancers (see 12-hydroxyeicosatetraenoic acid#cancer).
# Evolution
The CYP3A4 gene exhibits a much more complicated upstream regulatory region in comparison with its paralogs.[8] This increased complexity renders the CYP3A4 gene more sensitive to endogenous and exogenous PXR and CAR ligands, instead of relying on gene variants for wider specificity.[8] Chimpanzee and human CYP3A4 are highly conserved in metabolism of many ligands, although four amino acids positively selected in humans led to a 5-fold benzylation of 7-BFC in the presence of the hepatotoxic secondary bile acid lithocholic acid.[9] This change in consequence contributes to an increased human defense against cholestasis.[9]
# Tissue distribution
Fetuses do not really express CYP3A4 in their liver tissue,[clarification needed] but rather CYP3A7 (EC 1.14.14.1), which acts on a similar range of substrates. CYP3A4 is absent in fetal liver but increases to approximately 40% of adult levels in the fourth month of life and 72% at 12 months.[10][11]
Although CYP3A4 is predominantly found in the liver, it is also present in other organs and tissues of the body, where it may play an important role in metabolism. CYP3A4 in the intestine plays an important role in the metabolism of certain drugs. Often this allows prodrugs to be activated and absorbed – as in the case of the histamine H1-receptor antagonist terfenadine.
Recently CYP3A4 has also been identified in the brain, however its role in the central nervous system is still unknown.[12]
# Mechanisms
Cytochrome P450 enzymes perform an assortment of modifications on a variety of ligands, utilizing its large active site and its ability to bind more than one substrate at a time to perform complicated chemical alterations in the metabolism of endogenous and exogenous compounds. These include hydroxylation, epoxidation of olefins, aromatic oxidation, heteroatom oxidations, N- and O- dealkylation reactions, aldehyde oxidations, dehydrogenation reactions, and aromatase activity.[13][14]
Hydroxylation of an sp3 C-H bond is one of the ways in which CYP3A4 (and cytochrome P450 oxygenases) affects its ligand.[15] In fact, hydroxylation is sometimes followed by dehydrogenation, leading to more complex metabolites.[14] An example of a molecule that undergoes more than one reaction due to CYP3A4 includes tamoxifen, which is hydroxylated to 4-hydroxy-tamoxifen and then dehydrated to 4-hydroxy-tamoxifen quinone methide.[14] Two mechanisms have been proposed as the primary pathway of hydroxylation in P450 enzymes.
The first pathway suggested is a cage-controlled radical method ("oxygen rebound"), and the second involves a concerted mechanism that does not utilize a radical intermediate but instead acts very quickly via a "radical clock".[15]
# Inhibition through fruit ingestion
In 1998, various researchers showed that grapefruit juice, and grapefruit in general, is a potent inhibitor of CYP3A4, which can affect the metabolism of a variety of drugs, increasing their bioavailability.[16][17][18][19][20] In some cases, this can lead to a fatal interaction with drugs like astemizole or terfenadine.[17] The effect of grapefruit juice with regard to drug absorption was originally discovered in 1989. The first published report on grapefruit drug interactions was in 1991 in the Lancet entitled "Interactions of Citrus Juices with Felodipine and Nifedipine", and was the first reported food-drug interaction clinically. The effects of grapefruit last from 3–7 days, with the greatest effects when juice is taken an hour previous to administration of the drug.[21]
In addition to grapefruit, other fruits have similar effects. Noni (M. citrifolia), for example, is a dietary supplement typically consumed as a juice and also inhibits CYP3A4;[22] pomegranate juice has this effect as well.[23]
# Variability
While over 28 single nucleotide polymorphisms (SNPs) have been identified in the CYP3A4 gene, it has been found that this does not translate into significant interindividual variability in vivo. It can be supposed that this may be due to the induction of CYP3A4 on exposure to substrates.
CYP3A4 alleles which have been reported to have minimal function compared to wild-type include CYP3A4*6 (an A17776 insertion) and CYP3A4*17 (F189S). Both of these SNPs led to decreased catalytic activity with certain ligands, including testosterone and nifedipine in comparison to wild-type metabolism.[24]
Variability in CYP3A4 function can be determined noninvasively by the erythromycin breath test (ERMBT). The ERMBT estimates in vivo CYP3A4 activity by measuring the radiolabelled carbon dioxide exhaled after an intravenous dose of (14C-N-methyl)-erythromycin.[25]
# Induction
CYP3A4 is induced by a wide variety of ligands. These ligands bind to the pregnane X receptor (PXR). The activated PXR complex forms a heterodimer with the retinoid X receptor (RXR), which binds to the XREM region of the CYP3A4 gene. XREM is a regulatory region of the CYP3A4 gene, and binding causes a cooperative interaction with proximal promoter regions of the gene, resulting in increased transcription and expression of CYP3A4. Activation of the PXR/RXR heterodimer initiates transcription of the CYP3A4 promoter region and gene. Ligand binding increases when in the presence of CYP3A4 ligands, such as in the presence of aflatoxin B1, M1, and G1. Indeed, due to the enzyme's large and malleable active site, it is possible for the enzyme to bind multiple ligands at once, leading to potentially detrimental side effects.[26]
Induction of CYP3A4 has been shown to vary in humans depending on sex. Evidence shows an increased drug clearance by CYP3A4 in women, even when accounting for differences in body weight. A study by Wolbold et al. (2003) found that the median CYP3A4 levels measured from surgically removed liver samples of a random sample of women exceeded CYP3A4 levels in the livers of men by 129%. CYP3A4 mRNA transcripts were found in similar proportions, suggesting a pre-translational mechanism for the up-regulation of CYP3A4 in women. The exact cause of this elevated level of enzyme in women is still under speculation, however studies have elucidated other mechanisms (such as CYP3A5 or CYP3A7 compensation for lowered levels of CYP3A4) that affect drug clearance in both men and women.[27]
CYP3A4 substrate activation varies amongst different animal species. Certain ligands activate human PXR, which promotes CYP3A4 transcription, while showing no activation in other species. For instance, mouse PXR is not activated by rifampicin and human PXR is not activated by pregnenalone 16α-carbonitrile[28] In order to facilitate study of CYP3A4 functional pathways in vivo, mouse strains have been developed using transgenes in order to produce null/human CYP3A4 and PXR crosses. Although humanized hCYP3A4 mice successfully expressed the enzyme in their intestinal tract, low levels of hCYP3A4 were found in the liver.[28] This effect has been attributed to CYP3A4 regulation by the growth hormone signal transduction pathway.[28] In addition to providing an in vivo model, humanized CYP3A4 mice (hCYP3A4) have been used to further emphasize gender differences in CYP3A4 activity.[28]
CYP3A4 activity levels have also been linked to diet and environmental factors, such as duration of exposure to xenobiotic substances.[29] Due to the enzyme's extensive presence in the intestinal mucosa, the enzyme has shown sensitivity to starvation symptoms and is upregulated in defense of adverse effects. Indeed, in fatheaded minnows, unfed female fish were shown to have increased PXR and CYP3A4 expression, and displayed a more pronounced response to xenobiotic factors after exposure after several days of starvation.[29] By studying animal models and keeping in mind the innate differences in CYP3A4 activation, investigators can better predict drug metabolism and side effects in human CYP3A4 pathways.
# Turnover
Estimates of the turnover rate of human CYP3A4 vary widely. For hepatic CYP3A4, in vivo methods yield estimates of enzyme half-life mainly in the range of 70 to 140 hours, whereas in vitro methods give estimates from 26 to 79 hours.[30] Turnover of gut CYP3A4 is likely to be a function of the rate of enterocyte renewal; an indirect approach based on recovery of activity following exposure to grapefruit juice yields measurements in the 12- to 33-hour range.[30]
# Technology
Due to membrane-bound CYP3A4's natural propensity to conglomerate, it has historically been difficult to study drug binding in both solution and on surfaces. Co-crystallization is difficult since the substrates tend to have a low Kd (between 5-150 μM) and low solubility in aqueous solutions.[31] A successful strategy in isolating the bound enzyme is the functional stabilization of monomeric CYP3A4 on silver nanoparticles produced from nanosphere lithography and analyzed via localized surface plasmon resonance spectroscopy (LSPR).[32] These analyses can be used as a high-sensitivity assay of drug binding, and may become integral in further high-throughput assays utilized in initial drug discovery testing. In addition to LSPR, CYP3A4-Nanodisc complexes have been found helpful in other applications including solid-state NMR, redox potentiometry, and steady-state enzyme kinetics.[32]
# CYP3A4 ligands
Following is a table of selected substrates, inducers and inhibitors of CYP3A4. Where classes of agents are listed, there may be exceptions within the class.
Inhibitors of CYP3A4 can be classified by their potency, such as:
- Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.[33]
- Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.[33]
- Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.[33]
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- ↑ The interactive pathway map can be edited at WikiPathways: "IrinotecanPathway_WP46359"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | https://www.wikidoc.org/index.php/CYP3A4 | |
fc2de413c06439d47cb65a87f966f6627b0b4538 | wikidoc | CYP3A5 | CYP3A5
Cytochrome P450 3A5 is a protein that in humans is encoded by the CYP3A5 gene.
# Tissue distribution
CYP3A5 encodes a member of the cytochrome P450 superfamily of enzymes. Like most of the Cytochrome P450, the CYP3A5 is expressed in the prostate and the liver. It is also expressed in epithelium of the small intestine and large intestine for uptake and in small amounts in the bile duct, nasal mucosa, kidney, adrenal cortex, epithelium of the gastric mucosa with intestinal metaplasia, gallbladder, intercalated ducts of the pancreas, chief cells of the parathyroid and the corpus luteum of the ovary (at protein level).
# Clinical significance
The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and its expression is induced by glucocorticoids and some pharmacological agents. The enzyme metabolizes drugs such as nifedipine and cyclosporine as well as the steroid hormones testosterone, progesterone and androstenedione. This gene is part of a cluster of cytochrome P450 genes on chromosome 7q21.1. This cluster includes a pseudogene, CYP3A5P1, which is very similar to CYP3A5. This similarity has caused some difficulty in determining whether cloned sequences represent the gene or the pseudogene.
CYP3A4/3A5 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. Immunoblot analysis of liver microsomes showed that CYP3A5 is expressed as a 52.5-kD protein, whereas CYP3A4 migrates as a 52.0-kD protein. The human CYP3A subfamily, CYP3A4, CYP3A5, CYP3A7 and CYP3A43, is one of the most versatile of the biotransformation systems that facilitate the elimination of drugs (37% of the 200 most frequently prescribed drugs in the U.S.
CYP3A4 and CYP3A5 together account for approximately 30% of hepatic cytochrome P450, and approximately half of medications that are oxidatively metabolized by P450 are CYP3A substrates. Both CYP3A4 and CYP3A5 are expressed in liver and intestine, with CYP3A5 being the predominant form expressed in extrahepatic tissues.
# Allele distribution
The CYP3A5 gene has several functional variants, which vary depending on ethnicity. The CYP3A5*1 allele is associated with a normal metabolization of medication. It is most common among individuals native to Sub-Equatorial Africa, though the mutation also occurs at low frequencies in other populations. The CYP3A5*3 allele is linked with a poor metabolization of medication. It is near fixation in Europe, and is likewise found at high frequencies in West Asia and Central Asia, as well as among Afro-Asiatic (Hamitic-Semitic) speaking populations in North Africa and the Horn of Africa. Additionally, the mutation occurs at moderate-to-high frequencies in South Asia, Southeast Asia and East Asia, and at low frequencies in Sub-Equatorial Africa.
Global distribution of the CYP3A5 alleles:
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles.
- ↑ The interactive pathway map can be edited at WikiPathways: "IrinotecanPathway_WP46359"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | CYP3A5
Cytochrome P450 3A5 is a protein that in humans is encoded by the CYP3A5 gene.
# Tissue distribution
CYP3A5 encodes a member of the cytochrome P450 superfamily of enzymes. Like most of the Cytochrome P450, the CYP3A5 is expressed in the prostate and the liver.[1] It is also expressed in epithelium of the small intestine and large intestine for uptake and in small amounts in the bile duct, nasal mucosa, kidney, adrenal cortex, epithelium of the gastric mucosa with intestinal metaplasia, gallbladder, intercalated ducts of the pancreas, chief cells of the parathyroid and the corpus luteum of the ovary (at protein level).[1]
# Clinical significance
The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and its expression is induced by glucocorticoids and some pharmacological agents. The enzyme metabolizes drugs such as nifedipine and cyclosporine as well as the steroid hormones testosterone, progesterone and androstenedione. This gene is part of a cluster of cytochrome P450 genes on chromosome 7q21.1. This cluster includes a pseudogene, CYP3A5P1, which is very similar to CYP3A5. This similarity has caused some difficulty in determining whether cloned sequences represent the gene or the pseudogene.[2]
CYP3A4/3A5 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics.[1] Immunoblot analysis of liver microsomes showed that CYP3A5 is expressed as a 52.5-kD protein, whereas CYP3A4 migrates as a 52.0-kD protein.[3] The human CYP3A subfamily, CYP3A4, CYP3A5, CYP3A7 and CYP3A43, is one of the most versatile of the biotransformation systems that facilitate the elimination of drugs (37% of the 200 most frequently prescribed drugs in the U.S.[4]
CYP3A4 and CYP3A5 together account for approximately 30% of hepatic cytochrome P450, and approximately half of medications that are oxidatively metabolized by P450 are CYP3A substrates.[5] Both CYP3A4 and CYP3A5 are expressed in liver and intestine, with CYP3A5 being the predominant form expressed in extrahepatic tissues.[5]
# Allele distribution
The CYP3A5 gene has several functional variants, which vary depending on ethnicity. The CYP3A5*1 allele is associated with a normal metabolization of medication. It is most common among individuals native to Sub-Equatorial Africa, though the mutation also occurs at low frequencies in other populations. The CYP3A5*3 allele is linked with a poor metabolization of medication. It is near fixation in Europe, and is likewise found at high frequencies in West Asia and Central Asia, as well as among Afro-Asiatic (Hamitic-Semitic) speaking populations in North Africa and the Horn of Africa. Additionally, the mutation occurs at moderate-to-high frequencies in South Asia, Southeast Asia and East Asia, and at low frequencies in Sub-Equatorial Africa.[6][7]
Global distribution of the CYP3A5 alleles:[7]
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- ↑ The interactive pathway map can be edited at WikiPathways: "IrinotecanPathway_WP46359"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | https://www.wikidoc.org/index.php/CYP3A5 | |
9b0e32fc222dee2950d711b3023e0f3ea6ffb2b7 | wikidoc | CYP3A7 | CYP3A7
CYP3A7 is an enzyme belonging to the cytochrome P450 family. It is 503 amino acids in size and shares 87% of its sequence with CYP3A4. It carries out a similar role in fetuses that CYP3A4 serves in adults. The gene location is 7q22.1.
The CYP3A group of enzymes are the most abundantly expressed members of the cytochrome P450 family in liver. They are responsible for the metabolism of more than 50% of all clinical pharmaceuticals.
# Notable alleles
The CYP3A7*1C allele is associated with poor outcomes in some cancer patients, possibly because of the effect of the enzyme on some chemotherapy agents. | CYP3A7
CYP3A7 is an enzyme belonging to the cytochrome P450 family. It is 503 amino acids in size and shares 87% of its sequence with CYP3A4. It carries out a similar role in fetuses that CYP3A4 serves in adults.[1] The gene location is 7q22.1.[2]
The CYP3A group of enzymes are the most abundantly expressed members of the cytochrome P450 family in liver. They are responsible for the metabolism of more than 50% of all clinical pharmaceuticals.[3]
# Notable alleles
The CYP3A7*1C allele is associated with poor outcomes in some cancer patients, possibly because of the effect of the enzyme on some chemotherapy agents.[4] | https://www.wikidoc.org/index.php/CYP3A7 | |
d7c29d11026bd5cdfd31eb5dc7d491b63538f11f | wikidoc | CYP4F2 | CYP4F2
Leukotriene-B(4) omega-hydroxylase 1 is an enzyme that in humans is encoded by the CYP4F2 gene.
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, fatty acids, and other lipids. This protein localizes to the endoplasmic reticulum. The enzyme starts the process of inactivating and degrading leukotriene B4, a potent mediator of inflammation. This gene is part of a cluster of cytochrome P450 genes on chromosome 19. Another member of this family, CYP4F11, is approximately 16 kb away.
CYP4F2 along with CYP4A22, CYP4A11, and CYP4F3 and CYP2U1 also metabolize arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) by an Omega oxidation reaction with the predominant 20-HETE-synthesizing enzymes in humans being CYP4F2 followed by CYP4A11; 20-HETE regulates blood flow, vascularization, blood pressure, and kidney tubule absorption of ions in rodents and possibly humans. Gene polymorphism variants of CYP4F2 are associated with the development of hypertension, cerebral infarction (i.e. ischemic stroke), and myocardial infarction in humans (see 20-Hydroxyeicosatetraenoic acid for details).,
Members of the CYP4A and CYP4F sub-families may also ω-hydroxylate and thereby reduce the activity of various fatty acid metabolites of arachidonic acid including LTB4, 5-HETE, 5-oxo-eicosatetraenoic acid, 12-HETE, and several prostaglandins that are involved in regulating various inflammatory, vascular, and other responses in animals and humans. This hydroxylation-induced inactivation may underlie the proposed roles of the cytochromes in dampening inflammatory responses and the reported associations of certain CYP4F2 single nucleotide variants (SNPs) with human Crohn's disease (rs2108622) and Coeliac disease (rs3093156 and rs3093156). | CYP4F2
Leukotriene-B(4) omega-hydroxylase 1 is an enzyme that in humans is encoded by the CYP4F2 gene.[1][2][3]
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, fatty acids, and other lipids. This protein localizes to the endoplasmic reticulum. The enzyme starts the process of inactivating and degrading leukotriene B4, a potent mediator of inflammation. This gene is part of a cluster of cytochrome P450 genes on chromosome 19. Another member of this family, CYP4F11, is approximately 16 kb away.[3]
CYP4F2 along with CYP4A22, CYP4A11, and CYP4F3 and CYP2U1 also metabolize arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) by an Omega oxidation reaction with the predominant 20-HETE-synthesizing enzymes in humans being CYP4F2 followed by CYP4A11; 20-HETE regulates blood flow, vascularization, blood pressure, and kidney tubule absorption of ions in rodents and possibly humans.[4] Gene polymorphism variants of CYP4F2 are associated with the development of hypertension, cerebral infarction (i.e. ischemic stroke), and myocardial infarction in humans (see 20-Hydroxyeicosatetraenoic acid for details).,[5][6][7][7][8][6][7][9][9][10][11][12][13]
Members of the CYP4A and CYP4F sub-families may also ω-hydroxylate and thereby reduce the activity of various fatty acid metabolites of arachidonic acid including LTB4, 5-HETE, 5-oxo-eicosatetraenoic acid, 12-HETE, and several prostaglandins that are involved in regulating various inflammatory, vascular, and other responses in animals and humans.[14][15] This hydroxylation-induced inactivation may underlie the proposed roles of the cytochromes in dampening inflammatory responses and the reported associations of certain CYP4F2 single nucleotide variants (SNPs) with human Crohn's disease (rs2108622)[16] and Coeliac disease (rs3093156 and rs3093156).[17][18][19][20][21] | https://www.wikidoc.org/index.php/CYP4F2 | |
a3b5c6bf6ea02affdaff2034e1faa199c369f4e3 | wikidoc | CYP4F3 | CYP4F3
Leukotriene-B(4) omega-hydroxylase 2 is an enzyme that in humans is encoded by the CYP4F3 gene. CYP4F3 encodes two distinct enzymes, CYP4F3A and CYP4F3B, which originate from the alternative splicing of a single pre-mRNA precursor molecule; selection of either isoform is tissue-specific with CYP3F3A being expressed mostly in leukocytes and CYP4F3B mostly in the liver.
# Function
The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, fatty acids and other lipids. CYP4F3 actually encodes two splice-variants, CYP4F3A and CYP4F3B, of the cytochrome P450 superfamily of enzymes. The gene is part of a cluster of cytochrome P450 genes on chromosome 19. Another member of this family, CYP4F8, is approximately 18 kb away. Both variants localize on the endoplasmic reticulum and metabolize leukotriene B4 and very likely 5-hydroxyeicosatetraenoic acid, 5-oxo-eicosatetraenoic acid, and 12-hydroxyeicosatetraenoic acid by an omega oxidation reaction, i.e. by adding a hydroxyl residue to their terminal (i.e. C-20) carbon. This addition starts the process of inactivating and degrading all of these well-known mediators of inflammation and/or allery. CYP3FA is the major enzyme accomplishing these omega oxidations in leukocytes. The hydroxylation-induced inactivation of these mediators, perhaps particularly of leukotriene B4, may underlie the proposed roles of these cytochromes in dampening inflammatory responses as well as the reported associations of certain CYP4F3 single nucleotide variants (SNPs) with human Krohn's disease (SNPs are designated Rs1290617 and rs1290620 and Celiac disease (rs1290622 and rs1290625).
CYP4F3A and/or CYP43B also omega oxidize arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) as well as epoxyeicosatrienoic acids (EETs) to 20-hydroxy-EETs. 20-HETE regulates blood flow, vascularization, blood pressure, and kidney tubule absorption of ions in rodents and possibly humans; it has also been proposed to be involved in regulating the growth of various types of human cancers (see 20-Hydroxyeicosatetraenoic acid#cancer). EETS have a similar set of regulatory functions but often act in a manner opposite to 20-HETE (see epoxyeicosatrienoic acid#cancer); since, however, the activities of the 20-HEETs have not been well-defined, the function of EET omega oxidation is unclear. | CYP4F3
Leukotriene-B(4) omega-hydroxylase 2 is an enzyme that in humans is encoded by the CYP4F3 gene.[1][2][3] CYP4F3 encodes two distinct enzymes, CYP4F3A and CYP4F3B, which originate from the alternative splicing of a single pre-mRNA precursor molecule; selection of either isoform is tissue-specific with CYP3F3A being expressed mostly in leukocytes and CYP4F3B mostly in the liver.[4]
# Function
The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, fatty acids and other lipids. CYP4F3 actually encodes two splice-variants, CYP4F3A and CYP4F3B, of the cytochrome P450 superfamily of enzymes. The gene is part of a cluster of cytochrome P450 genes on chromosome 19. Another member of this family, CYP4F8, is approximately 18 kb away.[3] Both variants localize on the endoplasmic reticulum and metabolize leukotriene B4 and very likely 5-hydroxyeicosatetraenoic acid, 5-oxo-eicosatetraenoic acid, and 12-hydroxyeicosatetraenoic acid by an omega oxidation reaction, i.e. by adding a hydroxyl residue to their terminal (i.e. C-20) carbon.[5] This addition starts the process of inactivating and degrading all of these well-known mediators of inflammation and/or allery.[6] CYP3FA is the major enzyme accomplishing these omega oxidations in leukocytes.[6] The hydroxylation-induced inactivation of these mediators, perhaps particularly of leukotriene B4, may underlie the proposed roles of these cytochromes in dampening inflammatory responses as well as the reported associations of certain CYP4F3 single nucleotide variants (SNPs) with human Krohn's disease (SNPs are designated Rs1290617[7] and rs1290620[8] and Celiac disease (rs1290622 and rs1290625).[4][9][10][10][11][12]
CYP4F3A and/or CYP43B also omega oxidize arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) as well as epoxyeicosatrienoic acids (EETs) to 20-hydroxy-EETs.[6] 20-HETE regulates blood flow, vascularization, blood pressure, and kidney tubule absorption of ions in rodents and possibly humans;[4] it has also been proposed to be involved in regulating the growth of various types of human cancers (see 20-Hydroxyeicosatetraenoic acid#cancer). EETS have a similar set of regulatory functions but often act in a manner opposite to 20-HETE (see epoxyeicosatrienoic acid#cancer); since, however, the activities of the 20-HEETs have not been well-defined, the function of EET omega oxidation is unclear.[4] | https://www.wikidoc.org/index.php/CYP4F3 | |
6ade582da774be0cfb11b7fedd2616322e504a2c | wikidoc | CYP4F8 | CYP4F8
Cytochrome P450 4F8 is a protein that in humans is encoded by the CYP4F8 gene.
# Function
This gene, CYP4F8, encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and functions as a 19-hydroxylase of the arachidonic acid metabolite, prostaglandin H2 (PGH2) and the Dihomo-γ-linolenic acid metabolite PGH1 in seminal vesicles. This gene is part of a cluster of cytochrome P450 genes on chromosome 19. Another member of this family, CYP4F3, is approximately 18 kb away. In addition to seminal vesicles, CYP4F8 is expressed in kidney, prostate, epidermis, and corneal epithelium, and its mRNA has been found in retina; CYP4F8 is also greatly up-regulated in psoriatic skin.
In addition to its ability to metabolize and presumably thereby to inactivate or reduce the activity of PGH2 and PGH1, CYP4F8 adds hydroxyl residues to carbons 18 and 19 of arachidonic acid and Dihomo-γ-linolenic acid, CYP458 possesses epoxygenase activity in that it metabolizes the omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid, (EPA) to their corresponding epoxides, the epoxydocosapentaenoic acids (EDPs) and epoxyeicosatetraenoic acids (EEQs), respectively. The enzyme metabolizes DHA primarily to 19R,20S-epoxyeicosapentaenoic acid and 19S,20R-epoxyeicosapentaenoic acid isomers (termed 19,20-EDP) and EPA primarily to 17R,18S-eicosatetraenic acid and 17S,18R-eicosatetraenic acid isomers (termed 17,18-EEQ). 19-HETE is an inhibitor of 20-HETE, a broadly active signaling molecule which acts to onstrict arterioles, elevate blood pressure, promote inflammation responses, and stimulats the growth of various types of tumor cells; however the in vivo ability and significance of 19-HETE in inhibiting 20-HETE has not been demonstrated (see 20-Hydroxyeicosatetraenoic acid). The EDPs (see Epoxydocosapentaenoic acid) and EEQs (see epoxyeicosatetraenoic acid) have a broad range of activities. In various animal models and in vitro studies on animal and human tissues, they decrease hypertension and pain perception; suppress inflammation; inhibit angiogenesis, endothelial cell migration and endothelial cell proliferation; and inhibit the growth and metastasis of human breast and prostate cancer cell lines. It is suggested that the EDP and EEQ metabolites function in humans as they do in animal models and that, as products of the omega-3 fatty acids, DHA acid and EPA, the EDP and EEQ metabolites contribute to many of the beneficial effects attributed to dietary omega-3 fatty acids. EDP and EEQ metabolites are short-lived, being inactivated within seconds or minutes of formation by epoxide hydrolases, particularly soluble epoxide hydrolase, and therefore act locally.
CYP4F8 has little activity in omega-hydroxylating leukotriene B4, prostaglandin D2, prostaglandin E2, prostaglandin E1, or prostaglandin F2.
The fatty acid metabolizing activity, including the ability to form epoxides, of CYP4F8 is very similar to that of CYP4F12. However, it and CYP4F12 are not regarded as being major contributors in forming the cited epoxides in humans although they might do so in tissues where they are highly expressed. | CYP4F8
Cytochrome P450 4F8 is a protein that in humans is encoded by the CYP4F8 gene.[1][2]
# Function
This gene, CYP4F8, encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This protein localizes to the endoplasmic reticulum and functions as a 19-hydroxylase of the arachidonic acid metabolite, prostaglandin H2 (PGH2) and the Dihomo-γ-linolenic acid metabolite PGH1 in seminal vesicles. This gene is part of a cluster of cytochrome P450 genes on chromosome 19. Another member of this family, CYP4F3, is approximately 18 kb away.[2] In addition to seminal vesicles, CYP4F8 is expressed in kidney, prostate, epidermis, and corneal epithelium, and its mRNA has been found in retina; CYP4F8 is also greatly up-regulated in psoriatic skin.[3]
In addition to its ability to metabolize and presumably thereby to inactivate or reduce the activity of PGH2 and PGH1, CYP4F8 adds hydroxyl residues to carbons 18 and 19 of arachidonic acid and Dihomo-γ-linolenic acid,[4] CYP458 possesses epoxygenase activity in that it metabolizes the omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid, (EPA) to their corresponding epoxides, the epoxydocosapentaenoic acids (EDPs) and epoxyeicosatetraenoic acids (EEQs), respectively.[5] The enzyme metabolizes DHA primarily to 19R,20S-epoxyeicosapentaenoic acid and 19S,20R-epoxyeicosapentaenoic acid isomers (termed 19,20-EDP) and EPA primarily to 17R,18S-eicosatetraenic acid and 17S,18R-eicosatetraenic acid isomers (termed 17,18-EEQ).[5] 19-HETE is an inhibitor of 20-HETE, a broadly active signaling molecule which acts to onstrict arterioles, elevate blood pressure, promote inflammation responses, and stimulats the growth of various types of tumor cells; however the in vivo ability and significance of 19-HETE in inhibiting 20-HETE has not been demonstrated (see 20-Hydroxyeicosatetraenoic acid). The EDPs (see Epoxydocosapentaenoic acid) and EEQs (see epoxyeicosatetraenoic acid) have a broad range of activities. In various animal models and in vitro studies on animal and human tissues, they decrease hypertension and pain perception; suppress inflammation; inhibit angiogenesis, endothelial cell migration and endothelial cell proliferation; and inhibit the growth and metastasis of human breast and prostate cancer cell lines.[6][7][8][9] It is suggested that the EDP and EEQ metabolites function in humans as they do in animal models and that, as products of the omega-3 fatty acids, DHA acid and EPA, the EDP and EEQ metabolites contribute to many of the beneficial effects attributed to dietary omega-3 fatty acids.[6][9][10] EDP and EEQ metabolites are short-lived, being inactivated within seconds or minutes of formation by epoxide hydrolases, particularly soluble epoxide hydrolase, and therefore act locally.
CYP4F8 has little activity in omega-hydroxylating leukotriene B4, prostaglandin D2, prostaglandin E2, prostaglandin E1, or prostaglandin F2.[11]
The fatty acid metabolizing activity, including the ability to form epoxides, of CYP4F8 is very similar to that of CYP4F12. However, it and CYP4F12 are not regarded as being major contributors in forming the cited epoxides in humans although they might do so in tissues where they are highly expressed.[4] | https://www.wikidoc.org/index.php/CYP4F8 | |
0a08bca7492e44e486ba87cdb4a7ed7c09b98f01 | wikidoc | CYP4Z1 | CYP4Z1
CYP4Z1 (cytochrome P450, family 4, subfamily Z, polypeptide 1) is a protein that in humans is encoded by the CYP4Z1 gene.
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This gene is part of a cluster of cytochrome P450 genes on chromosome 1p33.
# Clinical significance
CYP4Z1 is overexpressed in breast cancer cells. It has also been demonstrated that the expression of the CYP4Z1 gene is upregulated by activated glucocorticoid and progesterone receptors. The overexpression of CYP4Z1 is associated with the breast cancer cells' increased production of 20-Hydroxyeicosatetraenoic acid (20-HETE); it is hypothesized that CYP4Z1 metabolizes arachidonic acid to 20-HETE and that this overproduction is responsible for increasing the growth and spread of breast cancer cells in human breast cancer. CPZ4Z1 is likewise overexpressed in ovarian cancer cells. These studies also suggest that CYP4Z1 will be a valuable marker to distinguish between benign and malignant breast and ovarian growths in humans and/or the prognoses of malignant growths in these tissues. | CYP4Z1
CYP4Z1 (cytochrome P450, family 4, subfamily Z, polypeptide 1) is a protein that in humans is encoded by the CYP4Z1 gene.[1]
# Function
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This gene is part of a cluster of cytochrome P450 genes on chromosome 1p33.[2]
# Clinical significance
CYP4Z1 is overexpressed in breast cancer cells.[1] It has also been demonstrated that the expression of the CYP4Z1 gene is upregulated by activated glucocorticoid and progesterone receptors.[3] The overexpression of CYP4Z1 is associated with the breast cancer cells' increased production of 20-Hydroxyeicosatetraenoic acid (20-HETE); it is hypothesized that CYP4Z1 metabolizes arachidonic acid to 20-HETE and that this overproduction is responsible for increasing the growth and spread of breast cancer cells in human breast cancer.[4][5] CPZ4Z1 is likewise overexpressed in ovarian cancer cells.[5] These studies also suggest that CYP4Z1 will be a valuable marker to distinguish between benign and malignant breast and ovarian growths in humans and/or the prognoses of malignant growths in these tissues. | https://www.wikidoc.org/index.php/CYP4Z1 | |
04640be5f4533bd9d31e23e3f8e85d68ebb8bdbf | wikidoc | CYP7B1 | CYP7B1
25-hydroxycholesterol 7-alpha-hydroxylase also known as oxysterol and steroid 7-alpha-hydroxylase is an enzyme that in humans is encoded by the CYP7B1 gene. This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.
# Function
This endoplasmic reticulum membrane protein catalyzes the first reaction in the cholesterol catabolic pathway of extrahepatic tissues, which converts cholesterol to bile acids. This enzyme likely plays a minor role in total bile acid synthesis, but may also be involved in the development of atherosclerosis, neurosteroid metabolism and sex hormone synthesis.
CYP7B was discovered by Stapleton in a screen for transcripts expressed differentially in rat hippocampus versus the remainder of the brain. The encoded polypeptide, initially designated hct-1 (hippocampus transcript 1), had significant homology with CYP7A1. The protein was designated CYP7B1 by the P450 Nomenclature Committee. Expression of the recombinant protein demonstrated 7alpha-hydroxylation activity for steroids (DHEA, pregnenolone) and oxysterols including 25- and 27-hydroxycholesterol, confirmed by knockout in mouse that abolished oxysterol hydroxylation in liver and brain and steroid hydroxylation in multiple tissues. Reporter tagging of the Cyp7b1 gene demonstrated that the enzyme is widely expressed, particularly strongly in brain, liver, liver, kidney, heart, and spleen. | CYP7B1
25-hydroxycholesterol 7-alpha-hydroxylase also known as oxysterol and steroid 7-alpha-hydroxylase is an enzyme that in humans is encoded by the CYP7B1 gene.[1][2][3] This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.
# Function
This endoplasmic reticulum membrane protein catalyzes the first reaction in the cholesterol catabolic pathway of extrahepatic tissues, which converts cholesterol to bile acids. This enzyme likely plays a minor role in total bile acid synthesis, but may also be involved in the development of atherosclerosis, neurosteroid metabolism and sex hormone synthesis.[3]
CYP7B was discovered by Stapleton[4] in a screen for transcripts expressed differentially in rat hippocampus versus the remainder of the brain. The encoded polypeptide, initially designated hct-1 (hippocampus transcript 1), had significant homology with CYP7A1.[4] The protein was designated CYP7B1 by the P450 Nomenclature Committee. Expression of the recombinant protein demonstrated 7alpha-hydroxylation activity for steroids (DHEA, pregnenolone) and oxysterols including 25- and 27-hydroxycholesterol,[5][6][7] confirmed by knockout in mouse that abolished oxysterol hydroxylation in liver[8] and brain and steroid hydroxylation in multiple tissues.[9] Reporter tagging of the Cyp7b1 gene demonstrated that the enzyme is widely expressed, particularly strongly in brain, liver, liver, kidney, heart, and spleen.[9] | https://www.wikidoc.org/index.php/CYP7B1 | |
3f3c48c582618c7030a6d337561d5da0e1527b0b | wikidoc | CYP8B1 | CYP8B1
CYP8B1 (cytochrome P450, family 8, subfamily B, polypeptide 1) also known as sterol 12-alpha-hydroxylase is a protein which in humans is encoded by the CYP8B1 gene.
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.
CYP8B1 is an endoplasmic reticulum membrane protein and catalyzes the conversion of 7 alpha-hydroxy-4-cholesten-3-one into 7-alpha,12-alpha-dihydroxy-4-cholesten-3-one. The balance between these two steroids determines the relative amounts of the two primary bile acids, cholic acid and chenodeoxycholic acid, both of which are secreted in the bile. In the intestine these bile acids affect the solubility of cholesterol and other lipids, promoting their absorption.
CYP8B1 is unique among the cytochrome P450 genes in that it is intronless. | CYP8B1
CYP8B1 (cytochrome P450, family 8, subfamily B, polypeptide 1) also known as sterol 12-alpha-hydroxylase is a protein which in humans is encoded by the CYP8B1 gene.[1]
This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.
CYP8B1 is an endoplasmic reticulum membrane protein and catalyzes the conversion of 7 alpha-hydroxy-4-cholesten-3-one into 7-alpha,12-alpha-dihydroxy-4-cholesten-3-one. The balance between these two steroids determines the relative amounts of the two primary bile acids, cholic acid and chenodeoxycholic acid, both of which are secreted in the bile. In the intestine these bile acids affect the solubility of cholesterol and other lipids, promoting their absorption.
CYP8B1 is unique among the cytochrome P450 genes in that it is intronless.[2] | https://www.wikidoc.org/index.php/CYP8B1 | |
cb86dbbea38e993ef4ae1af906dd0a124c9381fa | wikidoc | Caco-2 | Caco-2
Caco-2 refers to a cell monolayer absorption model. Cell-based functional assays, such as the Caco-2 drug transport model for assessing intestinal transport, are extremely valuable for screening lead compounds in drug discovery.
The Caco-2 cell line was developed by the Sloan-Kettering Institute for Cancer Research through research conducted by Dr. Jorgen Fogh.
The Caco-2 cell line is widely used with in vitro assays to predict the absorption rate of candidate drug compounds across the intestinal epithelial cell barrier. The assay requires that drug absorption rates be determined 21 days after Caco-2 cell seeding to allow for monolayer formation and cell differentiation.
The Caco-2 cell line is a continuous line of heterogeneous human epithelial colorectal adenocarcinoma cells, developed by the Sloan-Kettering Institute for Cancer Research through research conducted by Dr. Jorgen Fogh.
Although derived from a colon (large intestine) carcinoma, when cultured under specific conditions the cells become differentiated and polarized such that their phenotype, morphologically and functionally, resembles the enterocytes lining the small intestine. Caco-2 cells express tight junctions, microvilli, and a number of enzymes and transporters that are characteristic of such enterocytes: peptidases, esterases, P-glycoprotein, uptake transporters for amino acids, bile acids carboxylic acids, etc. They are commercially available through the American Type Culture Collection (ATCC; Manassas, VA, USA).
When looking at Caco-2 cell cultures microscopically, it is evident even by visual inspection that the cells are heterogeneous. As a result, over the years the characteristics of the cells used in different laboratories around the world have diverged significantly, which makes it difficult to compare results across labs.
Caco-2 cells are most commonly used not as individual cells, but as a confluent monolayer on a cell culture insert filter (e.g., Transwell®). When cultured in this format, the cells differentiate to form a polarized epithelial cell monolayer that provides a physical and biochemical barrier to the passage of ions and small molecules
. The Caco-2 monolayer is widely used across the pharmaceutical industry as an in vitro model of the human small intestinal mucosa to predict the absorption of orally administered drugs. The correlation between the in vitro apparent permeability (P¬app) across Caco-2 monolayers and the in vivo fraction absorbed (fa) is well established.Transwell diagram
This application of Caco-2 cells was pioneered in the late 1980s by Ismael Hidalgo, working in the laboratory of Ron Borchardt at the University of Kansas, and Tom Raub, who was at the Upjohn Company at the time. Following stints at SmithKline Beecham and Rhone-Poulenc Rorer, Hidalgo went on to co-found a company, Absorption Systems, in 1996, where he remains as Chief Scientist.
The considerable impact of the Caco-2 cell monolayer model can be measured in at least two ways. First, considering that poor pharmacokinetic properties accounted for ~40% of drug failures in development in the early 1990s and only ~10% by 2009, an interval in which Caco-2 monolayers were widely used throughout the pharmaceutical industry to predict absorption, it is not unreasonable to attribute some of that shift to this simple yet powerful model. Second, the 1989 Gastroenterology paper that demonstrated the utility of the model for this application has been cited more than 1000 times since its publication.
The versatility of Caco-2 cells is demonstrated by the fact that, even to this day, they are serving as the basis for the creation of innovative new models that are contributing to our understanding of drug efflux transporters such as P-glycoprotein (ABCB1) and BCRP (ABCG2). RNA interference has been used to silence the expression of individual efflux transporters, either transiently or long-term. | Caco-2
Caco-2 refers to a cell monolayer absorption model. Cell-based functional assays, such as the Caco-2 drug transport model for assessing intestinal transport, are extremely valuable for screening lead compounds in drug discovery.
The Caco-2 cell line was developed by the Sloan-Kettering Institute for Cancer Research through research conducted by Dr. Jorgen Fogh.
The Caco-2 cell line is widely used with in vitro assays to predict the absorption rate of candidate drug compounds across the intestinal epithelial cell barrier. The assay requires that drug absorption rates be determined 21 days after Caco-2 cell seeding to allow for monolayer formation and cell differentiation.
The Caco-2 cell line is a continuous line of heterogeneous human epithelial colorectal adenocarcinoma cells, developed by the Sloan-Kettering Institute for Cancer Research through research conducted by Dr. Jorgen Fogh[1].
Although derived from a colon (large intestine) carcinoma, when cultured under specific conditions the cells become differentiated and polarized such that their phenotype, morphologically and functionally, resembles the enterocytes lining the small intestine[2][3]. Caco-2 cells express tight junctions, microvilli, and a number of enzymes and transporters that are characteristic of such enterocytes: peptidases, esterases, P-glycoprotein, uptake transporters for amino acids, bile acids carboxylic acids, etc. They are commercially available through the American Type Culture Collection (ATCC; Manassas, VA, USA).
When looking at Caco-2 cell cultures microscopically, it is evident even by visual inspection that the cells are heterogeneous. As a result, over the years the characteristics of the cells used in different laboratories around the world have diverged significantly, which makes it difficult to compare results across labs[4].
Caco-2 cells are most commonly used not as individual cells, but as a confluent monolayer on a cell culture insert filter (e.g., Transwell®). When cultured in this format, the cells differentiate to form a polarized epithelial cell monolayer that provides a physical and biochemical barrier to the passage of ions and small molecules[5]
[6]. The Caco-2 monolayer is widely used across the pharmaceutical industry as an in vitro model of the human small intestinal mucosa to predict the absorption of orally administered drugs. The correlation between the in vitro apparent permeability (P¬app) across Caco-2 monolayers and the in vivo fraction absorbed (fa) is well established[7].Transwell diagram
This application of Caco-2 cells was pioneered in the late 1980s by Ismael Hidalgo, working in the laboratory of Ron Borchardt at the University of Kansas, and Tom Raub, who was at the Upjohn Company at the time. Following stints at SmithKline Beecham and Rhone-Poulenc Rorer, Hidalgo went on to co-found a company, Absorption Systems, in 1996, where he remains as Chief Scientist.
The considerable impact of the Caco-2 cell monolayer model can be measured in at least two ways. First, considering that poor pharmacokinetic properties accounted for ~40% of drug failures in development in the early 1990s and only ~10% by 2009, an interval in which Caco-2 monolayers were widely used throughout the pharmaceutical industry to predict absorption, it is not unreasonable to attribute some of that shift to this simple yet powerful model. Second, the 1989 Gastroenterology paper that demonstrated the utility of the model for this application has been cited more than 1000 times since its publication.
The versatility of Caco-2 cells is demonstrated by the fact that, even to this day, they are serving as the basis for the creation of innovative new models that are contributing to our understanding of drug efflux transporters such as P-glycoprotein (ABCB1) and BCRP (ABCG2). RNA interference has been used to silence the expression of individual efflux transporters, either transiently[8] or long-term[9][10]. | https://www.wikidoc.org/index.php/Caco-2 | |
e081a7ac09e0b5879f53a554fd4f88ba9a76c2b3 | wikidoc | Cactus | Cactus
A cactus (plural: cacti, the word derives from Greek, thus the Latin plural "cacti" is etymologically inappropriate, though it is frequently used nonetheless as is otherwise singular "cactus") is any member of the succulent plant family Cactaceae, native to the Americas. They are often used as ornamental plants, but some are also crop plants.
Cacti are distinctive and unusual plants, which are adapted to extremely arid and hot environments, showing a wide range of anatomical and physiological features which conserve water. Their stems have expanded into green succulent structures containing the chlorophyll necessary for life and growth, while the leaves have become the spines for which cacti are so well known.
Cacti come in a wide range of shapes and sizes. The tallest is Pachycereus pringlei, with a maximum recorded height of 19.2 m, and the smallest is Blossfeldia liliputiana, only about 1 cm diameter at maturity. Cactus flowers are large, and like the spines and branches arise from areoles. Many cactus species are night blooming, as they are pollinated by nocturnal insects or small animals, principally moths and bats. Cactuses' sizes range from small and round to pole-like and tall.
# Description
The cacti are succulent plants that grow either as trees, shrubs or in the form of ground cover. Most species grow on the ground, but there is also a whole range of epiphytic species. In most species, except for the sub-family of the Pereskioideae (see image), the leaves are greatly or entirely reduced. The flowers, mostly radially symmetrical and hermaphrodite, bloom either by day or by night, depending on species. Their shape varies from tube-like through bell-like to wheel-shaped, and their size from 0.2 to 15-30 meters. Most of them have numerous sepals (from 5 to 50 or more), and change form from outside to inside, from bracts to petals. They have stamens in great numbers (from 50 to 1,500, rarely fewer). Nearly all species of cacti have a bitter sometimes milky sap contained within them. The berry-like fruits may contain few, but mostly many (3,000), seeds, which can be between 0.4 and 12 mm long.
The life of a cactus is seldom longer than 300 years, and there are cacti which live only 25 years (although these flower as early as their second year). The Saguaro cactus (Carnegiea gigantea) grows to a height of up to 15 meters (the record is 17 meters 67cm), but in its first ten years it grows only 10 centimeters. The "mother-in-law's cushion" (Echinocactus grusonii) reaches a height of 2.5 meters and a diameter of 1 meter and - at least on the Canaries - is already capable of flowering after 6 years. The diameter of cactus flowers ranges from 5 to 30 cm; the colors are often conspicuous and spectacular.
# Distribution
Cacti are almost exclusively New World plants. This means that they are native only in North America, South America, and the West Indies. There is however one exception, Rhipsalis baccifera; this species has a pantropical distribution, occurring in the Old World tropical Africa, Madagascar and Sri Lanka as well as in tropical America. This plant is thought to be a relatively recent colonist in the Old World (within the last few thousand years), probably carried as seeds in the digestive tracts of migratory birds. Many other cacti have become naturalized to similar environments in other parts of the world after being introduced by people. The Tehuacán Valley of Mexico has one of the richest occurrences of cacti in the world.
Cacti are believed to have evolved in the last 30 to 40 million years. Long ago, the Americas were joined to the other continents, but separated due to continental drift. Unique species in the New World must have developed after the continents had moved apart. Significant distance between the continents was only achieved in around the last 50 million years. This may explain why cacti are so rare in Africa as the continents had already separated when cacti evolved. Many succulent plants in both the Old and New World bear a striking resemblance to cacti, and are often called "cactus" in common usage. This is, however, due to parallel evolution; none of these are closely related to the Cactaceae.
Prickly pears (genus Opuntia) were imported into Australia in the 19th century to be used as a natural agricultural fence and to establish a cochineal dye industry, but quickly became a widespread weed. This invasive species is inedible for local herbivores and has rendered 40,000 km² of farming land unproductive.
# Adaptations to dry environment
Some environments, such as deserts, semi-deserts and dry steppes, receive little water in the form of precipitation. Plants that inhabit these dry areas are known as xerophytes, and many of them are succulents, with thick or reduced, "succulent", leaves. Apart a few exceptions (for example, the genus "Rhodocactus") all cacti are succulent plants, although not all succulent plants are cactuses. Like other succulents, these cactuses have a range of specific adaptations that enable them to survive in these environments.
Cacti have never lost their leaves completely; they have only reduced the size so that they reduce the surface area through which water can be lost by transpiration. In some species the leaves are still remarkably large and ordinary while in other species they have become microscopic but they still contain the stomata, xylem and phloem. Certain cactus species have also developed ephemeral leaves, which are leaves that last for a short period of time when the stem is still in its early stages of development. A good example of a species that has ephemeral leaves is the Opuntia ficus-indica, better known as the prickly pear. Cacti have also developed spines which allow less water to evaporate through transpiration by shading the plant, and defend the cactus against water-seeking animals. The spines grow from specialized structures called areoles. Very few members of the family have leaves, and when present these are usually rudimentary and soon fall off; they are typically awl-shaped and only 1-3 mm. long. Two genera, Pereskia and Pereskiopsis, do however retain large, non-succulent leaves 5-25 cm. long, and also non-succulent stems. Pereskia has now been determined to be the ancestral genus from which all other cactuses evolved.
Enlarged stems carry out photosynthesis and store water. Unlike many other succulents, the stem is the only part of a true cactus where this takes place. Much like many other plants that have waxy coatings on their leaves, Cacti often have a waxy coating on their stems to prevent water loss. This works by preventing water from spreading on the surface and allowing water to trickle down the stem to be absorbed by the roots and used for photosynthesis. Cacti have a thick, hard-walled, succulent stem - when it rains, water is stored in the stem. The stems are photosynthetic, green, and fleshy. The inside of the stem is either spongy or hollow (depending on the cactus). A thick, waxy coating keeps the water inside the cactus from evaporating.
The bodies of many cacti have become thickened during the course of evolution, and form water-retentive tissue and in many cases assume the optimal shape of the sphere (combining highest possible volume with lowest possible surface area). By reducing its surface area, the body of the plant is also protected against excessive sunlight.
Most cactuses have a short growing season and long dormancy. For example, a fully-grown Saguaro cactus (Carnegiea gigantea) can absorb up to 3,000 litres of water in ten days. This is helped by cactuses' ability to form new roots quickly. Only two hours after rain following a relatively long drought the formation of new roots begins. Apart from a few exceptions an extensively ramified root system is formed, which spreads out immediately beneath the surface. The salt concentration in the root cells is relatively high, so that when moisture is encountered, water can immediately be absorbed in the greatest possible quantity.
But the plant body itself is also capable of absorbing moisture (through the epidermis and the thorns), which for plants that are exposed to moisture almost entirely, or indeed in some cases solely, in the form of fog, is of the greatest importance for sustaining life.
Most cacti have very shallow roots that can spread out widely close to the surface of the ground to collect water, an adaptation to infrequent rains; in one examination, a young Saguaro only 12 cm. tall had a root system covering an area 2 meters in diameter, but with no roots more than 10 cm. deep. The larger columnar cactuses also develop a taproot, primarily for anchoring but also to reach deeper water supplies and mineral nutrients.
One feature distinguishes the cacti from all other plants: cacti possess areoles, as they are known. The areole appears like a cushion with a diameter of up to 15 mm. and is formed by two opposing buds in the angles of a leaf. From the upper bud develops either a blossom or a side shoot, from the lower bud develop thorns. The two buds of the areoles can lie very close together, but they can also sometimes be separated by several centimeters.
Like other succulents in the families of the Crassulaceae, Agavaceae (agaves), Euphorbiaceae (euphorbias), Liliaceae (lilies), Orchidaceae (orchids) and Vitaceae (vines), cacti reduce water loss through transpiration by Crassulacean acid metabolism. Here, transpiration does not take place during the day at the same time as photosynthesis, but at night. The plant stores the carbon dioxide chemically linked to malic acid until the daytime. During the day the stomata are closed and the plant releases the stored CO2 and uses it for photosynthesis. Because transpiration takes place during the cool humid night hours, water loss through transpiration is significantly reduced.
# Reproductive ecology
Some cactus flowers form long tubes (up to 30 centimetres) so that only moths can reach the nectar and thus pollinate the blossoms. There are also specialisations for bats, humming birds and particular species of bees. The duration of flowering is very variable. Many flowers, for example those of Selenicereus grandiflorus (Queen of the Night) are only fully open for two hours at night. Other cactuses flower for a whole week. Most cactuses are self-incompatible, and thus require a pollinator. A few are autogamous and are able to pollinate themselves. Fraileas only opens their flowers completely in exceptional circumstances; they mostly pollinate themselves or others with their flowers closed ("cleistogamy"). The flower itself has also undergone a further development: the ovary tends to become a completely protected area, protected by thorns, hairs and scales. Seed formation is very prolific, and the fruits are mostly fleshy, pleasant tasting and conspicuously coloured. Goats, birds, ants, mice and bats contribute significantly to the spreading of the seeds.
Because of the plants' high water-retention ability, detached parts of the plant can survive for long periods and are able to grow new roots anywhere on the plant body.
# History
Among the remains of the Aztec civilization, cactuses can be found repeatedly in pictorial representations, sculpture and drawings, principally Echinocactus grusonii. This cactus, also known as "Mother-in-law's Cushion," has great ritual significance - human sacrifices were carried out on these cactuses. Tenochtitlan (the earlier name of Mexico City) means "place of the sacred cactus." The coat of arms of Mexico to this day shows an eagle, snake, and cactus.
Economic exploitation of the cactus can also be traced back to the Aztecs. The North American Indians exploit the alkaloid content of many cactuses for ritual purposes. Today, besides their use as foodstuffs (jam, fruit, vegetables), their principal use is as a host for the cochineal insect, from which a red dye (carmine) is obtained which is used in Campari or high-quality lipsticks. Particularly in South America dead pillar cactuses yield valuable wood for construction. Some cactuses are also of pharmaceutical significance.
From the moment of their discovery by early European explorers, cactuses have aroused much interest: Christopher Columbus brought the first melocactuses to Europe. Scientific interest in them began in the 17th century. By 1737, twenty-four species were known, which Linnaeus grouped together as the genus "Cactus". With the passage of time cactuses enjoyed increasing popularity: sometimes they were of scientific interest only; at other times as fashionable plants they enjoyed a real boom.
From the beginning of the 20th century interest in cactuses has increased steadily, interrupted only by the two world wars. This was accompanied by a rising commercial interest, the negative consequences of which culminated in raids on the cactuses' native habitats, resulting in the extermination of many species. Through the great number of cactus admirers, whether their interest is scientific or hobby-oriented, new species and varieties are even today discovered every year.
All cactuses are covered by the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and many species by virtue of their inclusion in Appendix 1 are fully protected.
Some countries have a rather contradictory attitude to species protection. In Mexico for example to be caught in the act of digging up cactuses carries a prison sentence, but cactus habitats are destroyed for the construction of new roads and electricity lines. To be borne in mind here is that some cactus habitats have a total area of no more than 1,000 square meters. If this habitat is destroyed, either by construction or by plundering, the species growing there is lost for posterity if it is endemic (ie, growing in that one spot and nowhere else).
The Moche people of ancient Peru worshiped agriculture and often depicted the cactus in their art.
# Uses
Cactuses, cultivated by people worldwide, are a familiar sight as potted plants, houseplants or in ornamental gardens in warmer climates. They often form part of xeriphytic (dry) gardens in arid regions, or raised rockeries. Some countries, such as Australia, have water restrictions in many cities, so drought-resistant plants are increasing in popularity. Numerous species have entered widespread cultivation, including members of Echinopsis, Mammillaria and Cereus among others. Some, such as the Golden Barrel Cactus, Echinocactus grusonii, are prominent in garden design. Cactuses are commonly used for fencing material where there is a lack of either natural resources or financial means to construct a permanent fence. This is often seen in arid and warm climates, such as the Masai Mara in Kenya. This is known as a cactus fence. Cactuses fences are often used by homeowners and landscape architects for home security purposes. The sharp thorns of the cactus deter unauthorized persons from entering private properties, and may prevent break-ins if planted under windows and near drainpipes. The aesthetic characteristics of some species, in conjunction with their home security qualities, makes them a considerable alternative to artificial fences and walls.
As well as garden plants, many cactuses have important commercial uses; some cactuses bear edible fruit, such as the prickly pear and Hylocereus, which produces Dragon fruit or Pitaya. Opuntia are also used as host plants for cochineal bugs in the cochineal dye industry in Central America.
The Peyote, Lophophora williamsii, is a well-known psychoactive agent used by Native Americans in the Southwest of the United States of America. Some species of Echinopsis (previously Trichocereus) also have psychoactive properties. For example, the San Pedro cactus, a common specimen found in many garden centers, is known to contain mescaline.
# Etymology
The word cactus is ultimately derived from Greek Κακτος kaktos, used in classical Greek for a species of spiny thistle, possibly the cardoon, and used as a generic name, Cactus, by Linnaeus in 1753 (now rejected in favor of Mammillaria). There is some dispute as to the proper plural form of the word; as a Greek loan into English, the correct plural in English would be "cactoi" or "cactuses". However, as a word in Botanical Latin (as distinct from Classical Latin), "cactus" would follow standard Latin rules for pluralization and become "cacti", which has become the prevalent usage in English. Regardless, cactus is popularly used as both singular and plural, and is cited as both singular and plural by the Random House Unabridged Dictionary (2006). | Cactus
A cactus (plural: cacti, the word derives from Greek, thus the Latin plural "cacti" is etymologically inappropriate, though it is frequently used nonetheless as is otherwise singular "cactus") is any member of the succulent plant family Cactaceae, native to the Americas. They are often used as ornamental plants, but some are also crop plants.
Cacti are distinctive and unusual plants, which are adapted to extremely arid and hot environments, showing a wide range of anatomical and physiological features which conserve water. Their stems have expanded into green succulent structures containing the chlorophyll necessary for life and growth, while the leaves have become the spines for which cacti are so well known.
Cacti come in a wide range of shapes and sizes. The tallest is Pachycereus pringlei, with a maximum recorded height of 19.2 m,[1] and the smallest is Blossfeldia liliputiana, only about 1 cm diameter at maturity.[2] Cactus flowers are large, and like the spines and branches arise from areoles. Many cactus species are night blooming, as they are pollinated by nocturnal insects or small animals, principally moths and bats. Cactuses' sizes range from small and round to pole-like and tall.
# Description
The cacti are succulent plants that grow either as trees, shrubs or in the form of ground cover. Most species grow on the ground, but there is also a whole range of epiphytic species. In most species, except for the sub-family of the Pereskioideae (see image), the leaves are greatly or entirely reduced. The flowers, mostly radially symmetrical and hermaphrodite, bloom either by day or by night, depending on species. Their shape varies from tube-like through bell-like to wheel-shaped, and their size from 0.2 to 15-30 meters. Most of them have numerous sepals (from 5 to 50 or more), and change form from outside to inside, from bracts to petals. They have stamens in great numbers (from 50 to 1,500, rarely fewer). Nearly all species of cacti have a bitter sometimes milky sap contained within them. The berry-like fruits may contain few, but mostly many (3,000), seeds, which can be between 0.4 and 12 mm long.[3]
The life of a cactus is seldom longer than 300 years, and there are cacti which live only 25 years (although these flower as early as their second year). The Saguaro cactus (Carnegiea gigantea) grows to a height of up to 15 meters (the record is 17 meters 67cm), but in its first ten years it grows only 10 centimeters. The "mother-in-law's cushion" (Echinocactus grusonii) reaches a height of 2.5 meters and a diameter of 1 meter and - at least on the Canaries - is already capable of flowering after 6 years. The diameter of cactus flowers ranges from 5 to 30 cm; the colors are often conspicuous and spectacular.
# Distribution
Cacti are almost exclusively New World plants. This means that they are native only in North America, South America, and the West Indies. There is however one exception, Rhipsalis baccifera; this species has a pantropical distribution, occurring in the Old World tropical Africa, Madagascar and Sri Lanka as well as in tropical America. This plant is thought to be a relatively recent colonist in the Old World (within the last few thousand years), probably carried as seeds in the digestive tracts of migratory birds. Many other cacti have become naturalized to similar environments in other parts of the world after being introduced by people. The Tehuacán Valley of Mexico has one of the richest occurrences of cacti in the world.[4]
Cacti are believed to have evolved in the last 30 to 40 million years. Long ago, the Americas were joined to the other continents, but separated due to continental drift. Unique species in the New World must have developed after the continents had moved apart. Significant distance between the continents was only achieved in around the last 50 million years. This may explain why cacti are so rare in Africa as the continents had already separated when cacti evolved. Many succulent plants in both the Old and New World bear a striking resemblance to cacti, and are often called "cactus" in common usage. This is, however, due to parallel evolution; none of these are closely related to the Cactaceae.
Prickly pears (genus Opuntia) were imported into Australia in the 19th century to be used as a natural agricultural fence and to establish a cochineal dye industry, but quickly became a widespread weed. This invasive species is inedible for local herbivores and has rendered 40,000 km² of farming land unproductive.
# Adaptations to dry environment
Some environments, such as deserts, semi-deserts and dry steppes, receive little water in the form of precipitation. Plants that inhabit these dry areas are known as xerophytes, and many of them are succulents, with thick or reduced, "succulent", leaves. Apart a few exceptions (for example, the genus "Rhodocactus") all cacti are succulent plants, although not all succulent plants are cactuses. Like other succulents, these cactuses have a range of specific adaptations that enable them to survive in these environments.
Cacti have never lost their leaves completely; they have only reduced the size so that they reduce the surface area through which water can be lost by transpiration. In some species the leaves are still remarkably large and ordinary while in other species they have become microscopic but they still contain the stomata, xylem and phloem. Certain cactus species have also developed ephemeral leaves, which are leaves that last for a short period of time when the stem is still in its early stages of development. A good example of a species that has ephemeral leaves is the Opuntia ficus-indica, better known as the prickly pear. Cacti have also developed spines which allow less water to evaporate through transpiration by shading the plant, and defend the cactus against water-seeking animals. The spines grow from specialized structures called areoles. Very few members of the family have leaves, and when present these are usually rudimentary and soon fall off; they are typically awl-shaped and only 1-3 mm. long. Two genera, Pereskia and Pereskiopsis, do however retain large, non-succulent leaves 5-25 cm. long, and also non-succulent stems. Pereskia has now been determined to be the ancestral genus from which all other cactuses evolved.[5]
Enlarged stems carry out photosynthesis and store water. Unlike many other succulents, the stem is the only part of a true cactus where this takes place. Much like many other plants that have waxy coatings on their leaves, Cacti often have a waxy coating on their stems to prevent water loss. This works by preventing water from spreading on the surface and allowing water to trickle down the stem to be absorbed by the roots and used for photosynthesis. Cacti have a thick, hard-walled, succulent stem - when it rains, water is stored in the stem. The stems are photosynthetic, green, and fleshy. The inside of the stem is either spongy or hollow (depending on the cactus). A thick, waxy coating keeps the water inside the cactus from evaporating.
The bodies of many cacti have become thickened during the course of evolution, and form water-retentive tissue and in many cases assume the optimal shape of the sphere (combining highest possible volume with lowest possible surface area). By reducing its surface area, the body of the plant is also protected against excessive sunlight.
Most cactuses have a short growing season and long dormancy. For example, a fully-grown Saguaro cactus (Carnegiea gigantea) can absorb up to 3,000 litres of water in ten days. This is helped by cactuses' ability to form new roots quickly. Only two hours after rain following a relatively long drought the formation of new roots begins. Apart from a few exceptions an extensively ramified root system is formed, which spreads out immediately beneath the surface. The salt concentration in the root cells is relatively high, so that when moisture is encountered, water can immediately be absorbed in the greatest possible quantity.
But the plant body itself is also capable of absorbing moisture (through the epidermis and the thorns), which for plants that are exposed to moisture almost entirely, or indeed in some cases solely, in the form of fog, is of the greatest importance for sustaining life.
Most cacti have very shallow roots that can spread out widely close to the surface of the ground to collect water, an adaptation to infrequent rains; in one examination, a young Saguaro only 12 cm. tall had a root system covering an area 2 meters in diameter, but with no roots more than 10 cm. deep.[6] The larger columnar cactuses also develop a taproot, primarily for anchoring but also to reach deeper water supplies and mineral nutrients.[6]
One feature distinguishes the cacti from all other plants: cacti possess areoles, as they are known. The areole appears like a cushion with a diameter of up to 15 mm. and is formed by two opposing buds in the angles of a leaf. From the upper bud develops either a blossom or a side shoot, from the lower bud develop thorns. The two buds of the areoles can lie very close together, but they can also sometimes be separated by several centimeters.
Like other succulents in the families of the Crassulaceae, Agavaceae (agaves), Euphorbiaceae (euphorbias), Liliaceae (lilies), Orchidaceae (orchids) and Vitaceae (vines), cacti reduce water loss through transpiration by Crassulacean acid metabolism.[6] Here, transpiration does not take place during the day at the same time as photosynthesis, but at night. The plant stores the carbon dioxide chemically linked to malic acid until the daytime. During the day the stomata are closed and the plant releases the stored CO2 and uses it for photosynthesis. Because transpiration takes place during the cool humid night hours, water loss through transpiration is significantly reduced.
# Reproductive ecology
Some cactus flowers form long tubes (up to 30 centimetres) so that only moths can reach the nectar and thus pollinate the blossoms. There are also specialisations for bats, humming birds and particular species of bees. The duration of flowering is very variable. Many flowers, for example those of Selenicereus grandiflorus (Queen of the Night) are only fully open for two hours at night. Other cactuses flower for a whole week. Most cactuses are self-incompatible, and thus require a pollinator. A few are autogamous and are able to pollinate themselves. Fraileas only opens their flowers completely in exceptional circumstances; they mostly pollinate themselves or others with their flowers closed ("cleistogamy"). The flower itself has also undergone a further development: the ovary tends to become a completely protected area, protected by thorns, hairs and scales. Seed formation is very prolific, and the fruits are mostly fleshy, pleasant tasting and conspicuously coloured. Goats, birds, ants, mice and bats contribute significantly to the spreading of the seeds.
Because of the plants' high water-retention ability, detached parts of the plant can survive for long periods and are able to grow new roots anywhere on the plant body.
# History
Among the remains of the Aztec civilization, cactuses can be found repeatedly in pictorial representations, sculpture and drawings, principally Echinocactus grusonii. This cactus, also known as "Mother-in-law's Cushion," has great ritual significance - human sacrifices were carried out on these cactuses.[citation needed] Tenochtitlan (the earlier name of Mexico City) means "place of the sacred cactus." The coat of arms of Mexico to this day shows an eagle, snake, and cactus.
Economic exploitation of the cactus can also be traced back to the Aztecs. The North American Indians exploit the alkaloid content of many cactuses for ritual purposes. Today, besides their use as foodstuffs (jam, fruit, vegetables), their principal use is as a host for the cochineal insect, from which a red dye (carmine) is obtained which is used in Campari or high-quality lipsticks. Particularly in South America dead pillar cactuses yield valuable wood for construction. Some cactuses are also of pharmaceutical significance.
From the moment of their discovery by early European explorers, cactuses have aroused much interest: Christopher Columbus brought the first melocactuses to Europe. Scientific interest in them began in the 17th century. By 1737, twenty-four species were known, which Linnaeus grouped together as the genus "Cactus". With the passage of time cactuses enjoyed increasing popularity: sometimes they were of scientific interest only; at other times as fashionable plants they enjoyed a real boom.
From the beginning of the 20th century interest in cactuses has increased steadily, interrupted only by the two world wars. This was accompanied by a rising commercial interest, the negative consequences of which culminated in raids on the cactuses' native habitats, resulting in the extermination of many species. Through the great number of cactus admirers, whether their interest is scientific or hobby-oriented, new species and varieties are even today discovered every year.
All cactuses are covered by the Convention on International Trade in Endangered Species of Wild Fauna and Flora, and many species by virtue of their inclusion in Appendix 1 are fully protected.
Some countries have a rather contradictory attitude to species protection. In Mexico for example to be caught in the act of digging up cactuses carries a prison sentence, but cactus habitats are destroyed for the construction of new roads and electricity lines. To be borne in mind here is that some cactus habitats have a total area of no more than 1,000 square meters.[citation needed][dubious – discuss] If this habitat is destroyed, either by construction or by plundering, the species growing there is lost for posterity if it is endemic (ie, growing in that one spot and nowhere else).
The Moche people of ancient Peru worshiped agriculture and often depicted the cactus in their art. [7]
# Uses
Cactuses, cultivated by people worldwide, are a familiar sight as potted plants, houseplants or in ornamental gardens in warmer climates. They often form part of xeriphytic (dry) gardens in arid regions, or raised rockeries. Some countries, such as Australia, have water restrictions in many cities, so drought-resistant plants are increasing in popularity. Numerous species have entered widespread cultivation, including members of Echinopsis, Mammillaria and Cereus among others. Some, such as the Golden Barrel Cactus, Echinocactus grusonii, are prominent in garden design. Cactuses are commonly used for fencing material where there is a lack of either natural resources or financial means to construct a permanent fence. This is often seen in arid and warm climates, such as the Masai Mara in Kenya. This is known as a cactus fence. Cactuses fences are often used by homeowners and landscape architects for home security purposes. The sharp thorns of the cactus deter unauthorized persons from entering private properties, and may prevent break-ins if planted under windows and near drainpipes. The aesthetic characteristics of some species, in conjunction with their home security qualities, makes them a considerable alternative to artificial fences and walls.[8]
As well as garden plants, many cactuses have important commercial uses; some cactuses bear edible fruit, such as the prickly pear and Hylocereus, which produces Dragon fruit or Pitaya. Opuntia are also used as host plants for cochineal bugs in the cochineal dye industry in Central America.
The Peyote, Lophophora williamsii, is a well-known psychoactive agent used by Native Americans in the Southwest of the United States of America. Some species of Echinopsis (previously Trichocereus) also have psychoactive properties. For example, the San Pedro cactus, a common specimen found in many garden centers, is known to contain mescaline.
# Etymology
The word cactus is ultimately derived from Greek Κακτος kaktos, used in classical Greek for a species of spiny thistle, possibly the cardoon, and used as a generic name, Cactus, by Linnaeus in 1753 (now rejected in favor of Mammillaria). There is some dispute as to the proper plural form of the word; as a Greek loan into English, the correct plural in English would be "cactoi" or "cactuses". However, as a word in Botanical Latin (as distinct from Classical Latin), "cactus" would follow standard Latin rules for pluralization and become "cacti", which has become the prevalent usage in English. Regardless, cactus is popularly used as both singular and plural, and is cited as both singular and plural by the Random House Unabridged Dictionary (2006). | https://www.wikidoc.org/index.php/Cactus | |
9934dac2dcde9230e34263327acb8cc6c5da155d | wikidoc | Fibula | Fibula
The fibula or calf bone is a bone located on the lateral side of the tibia, with which it is connected above and below. It is the smaller of the two bones, and, in proportion to its length, the most slender of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below the level of the knee-joint, and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia, and forms the lateral part of the ankle-joint.
# Components
The bone has the following components:
- Head of fibula
- Body of fibula
- Lateral malleolus
- Interosseous membrane connecting the fibula to the tibia, forming a syndesmoses joint
# Blood Supply
The blood supply is important for planning free tissue transfer because the fibula is commonly used to reconstruct the mandible. The shaft is supplied in its middle third by a large nutrient vessel from the peroneal artery. It is also perfused from its periosteum which receives many small branches from the peroneal artery. The proximal head and the epiphysis are supplied by a branch of the anterior tibial artery. In harvesting the bone the middle third is always taken and the ends preserved (4cm proximally and 6cm distally)
# Ossification
The fibula is ossified from three centers, one for the shaft, and one for either end. Ossification begins in the body about the eighth week of fetal life, and extends toward the extremities. At birth the ends are cartilaginous.
Ossification commences in the lower end in the second year, and in the upper about the fourth year. The lower epiphysis, the first to ossify, unites with the body about the twentieth year; the upper epiphysis joins about the twenty-fifth year. | Fibula
Template:Infobox Bone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
The fibula or calf bone is a bone located on the lateral side of the tibia, with which it is connected above and below. It is the smaller of the two bones, and, in proportion to its length, the most slender of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below the level of the knee-joint, and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia, and forms the lateral part of the ankle-joint.
# Components
The bone has the following components:
- Head of fibula
- Body of fibula
- Lateral malleolus
- Interosseous membrane connecting the fibula to the tibia, forming a syndesmoses joint
# Blood Supply
The blood supply is important for planning free tissue transfer because the fibula is commonly used to reconstruct the mandible. The shaft is supplied in its middle third by a large nutrient vessel from the peroneal artery. It is also perfused from its periosteum which receives many small branches from the peroneal artery. The proximal head and the epiphysis are supplied by a branch of the anterior tibial artery. In harvesting the bone the middle third is always taken and the ends preserved (4cm proximally and 6cm distally)
# Ossification
The fibula is ossified from three centers, one for the shaft, and one for either end. Ossification begins in the body about the eighth week of fetal life, and extends toward the extremities. At birth the ends are cartilaginous.
Ossification commences in the lower end in the second year, and in the upper about the fourth year. The lower epiphysis, the first to ossify, unites with the body about the twentieth year; the upper epiphysis joins about the twenty-fifth year. | https://www.wikidoc.org/index.php/Calf_bone | |
05a9bd4529131798e02f84be1fc912b24c728378 | wikidoc | Callus | Callus
# Overview
A callus (or callous) is an especially toughened area of skin which has become relatively thick and hard as a response to repeated contact or pressure. In botany, the term is also used to announce a condition of thickened surfaces of leaves or other plant parts. Since repeated contact is required, calluses are most often found on hands or feet. Calluses are generally not harmful, but may sometimes lead to other problems, such as infection. Shoes that fit tightly can often produce calluses on the feet. String instrument players develop calluses where their fingers make contact with the strings, but these calluses are often desirable as they help alleviate the pain from the tension of the strings and make playing easier. Dancers often develop calluses on the soles of their feet from dancing barefoot, which makes performing turns less difficult. Video game players may develop calluses on their thumbs, especially if using a controller with a poor D-pad. Frequent use of a writing implement may lead to a callus on the middle finger, commonly known as a "writer's bump".
# Corns
Corns (also called clavi) are specially-shaped calluses of dead skin that usually occur on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsa of toes or fingers. They can sometimes occur on the thicker palmar or plantar skin surfaces. Corns form when the pressure point against the skin traces an elliptical or semi-elliptical path, the center of which is at the point of pressure, gradually widening. If there is constant stimulation of the tissues producing the corns, even after the corn is removed or the pressure surgically removed, the skin may continue to grow as a corn.
The name corn comes from its appearance under the microscope. The hard part at the center of the corn resembles a barley hare, that is, a funnel with a broad raised top and a pointed bottom. "Corn" used to be a generic term for grain, and the name stuck. The scientific name is heloma. Hard corns are called heloma durum, while soft corns are called heloma molle.
The place of occurrence differentiates between soft and hard corns. Hard corns occur on dry, flat surfaces of skin. Soft corns (frequently found between adjacent toes) stay moist, keeping the surrounding skin soft. The corn's center is not soft, however, but indurated.
# Development
Although usually found on the foot (where the most pressure occurs), calluses can occur anywhere on the body as a reaction to moderate, constant "grinding" pressure. It is the natural reaction of the palmar or plantar skin.
For example, players of string instruments will develop calluses on their fingers with frequent play. This actually helps the player as the thicker skin protects the fingertips - extended play is often painful before the calluses appear. If a beginning player plays too hard, or with an extended amount of left- (especially) or right-hand pizzicato, however, a blister may be produced instead.
Drummers can also develop a callus on their feet and hands. Calluses on the feet are more common in metal drummers, where double bass drumming is used more often. Use of older sticks will also cause callus on the palms and fingers of a drummer.
People with bunions may find painful calluses behind the second or third toe. These are caused by unequal pressure placed on the smaller toes. Such pressure-induced calluses can be very painful and often do not respond to trimming of the callus, soft materials, or orthotic devices. It is not the callus that causes pain, but rather the severe imbalance in the function of the foot that is taking its toll.
Shoes can produce corns by rubbing against the top of the toes or foot. Continued irritation may cause pain. Stretching the rubbing area of the shoe may reduce the pressure and stop the pain, but the corn may remain. If a toenail or a fingernail rubs against the skin, pinching it between surfaces for a period of time, a corn can form at the edge of the nail. These are difficult to treat because frequently the nail is the primary cause.
Sometimes a callus occurs where there is no rubbing or pressure. These hyperkeratoses can have a variety of causes. Some toxins, such as arsenic, can cause thick palms and soles. Some diseases, such as syphilis, can cause thickening of the palms and soles as well as pinpoint hyperkeratoses. There is a benign condition called keratosis palmaris et plantaris, which produces corns in the creases of the fingers and non-weight-bearing spaces of the feet. Some of this may be caused by actinic keratosis, which occurs due to overexposure to sun, or with age and hormonal shifts.
# Diagnosis
## Physical Examination
### Skin
- Callus. Adapted from Dermatology Atlas.
- Callus. Adapted from Dermatology Atlas.
- Callus. Adapted from Dermatology Atlas.
- Lip callosity. Adapted from Dermatology Atlas.
- Lip callosity. Adapted from Dermatology Atlas.
# Treatment
A common method, often done by a podiatrist, is to shave the calluses down, and perhaps pad them.
For calluses on the feet an inexpensive home remedy is to dissolve a foot soap powder composed of borax, iodine and bran in warm water and soak the feet in the solution for 15 to 20 minutes. This softens the calluses so that layers of dead skin can be rubbed away with a cloth towel. Repeated soaking over a period of several days can often allow removal of even the core with nothing more than the friction of the cloth towel. If this fails, use of a pumice stone can also remove the skin.
Most corns and calluses located under the foot are caused by the pressure of the foot bones against the skin, preventing it from moving with the shoe or the ground. While well-fitting shoes will help some of these problems, occasionally some other degree of intervention is required to completely rid the foot of the problem. The most basic treatment is to put a friction-reducing insole or material into the shoe, or against the foot. In some cases, this will reduce the painfulness without actually making the callus go away.
In many situations, a change in the function of the foot by use of an orthotic device is required. This reduces friction and pressure, allowing the skin to rest and to stop forming protective skin coverings.
Salicylic acid (0.5%-40%) can be used for two reasons, "(1) it decreases keratinocyte adhesion, and (2) it increases water binding which leads to hydration of the keratin."
Using a knife to cut it away is dangerous because it can result in bleeding of the foot and infection.
At other times, surgical correction of the pressure is needed.
# Diabetes
People with diabetes face special skin challenges. Because diabetes affects the capillaries, the small vessels which feed the skin its blood supply, thickening of the skin increases the difficulty to supply nutrients to the skin. Additionally, the shear and pressure forces that cause corns and calluses may tear the capillaries, causing bleeding within the callus or corn.
Often, bleeding within the calluses is an early sign of diabetes, even before elevated blood sugars. Although the bleeding can be small, sometimes small pools of blood or hematoma are formed. The blood itself is an irritant, a foreign body within the callus that makes the area burn or itch. If the pool of blood is exposed to the outside, infection may follow. Infection may lead to ulceration. Luckily, this process can be prevented at several places, but such infections can become life-threatening. Diabetic foot infections are the leading cause of diabetic limb amputation. | Callus
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2]
# Overview
A callus (or callous) is an especially toughened area of skin which has become relatively thick and hard as a response to repeated contact or pressure. In botany, the term is also used to announce a condition of thickened surfaces of leaves or other plant parts. Since repeated contact is required, calluses are most often found on hands or feet. Calluses are generally not harmful, but may sometimes lead to other problems, such as infection. Shoes that fit tightly can often produce calluses on the feet. String instrument players develop calluses where their fingers make contact with the strings, but these calluses are often desirable as they help alleviate the pain from the tension of the strings and make playing easier. Dancers often develop calluses on the soles of their feet from dancing barefoot, which makes performing turns less difficult. Video game players may develop calluses on their thumbs, especially if using a controller with a poor D-pad. Frequent use of a writing implement may lead to a callus on the middle finger, commonly known as a "writer's bump".
# Corns
Corns (also called clavi) are specially-shaped calluses of dead skin that usually occur on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsa of toes or fingers. They can sometimes occur on the thicker palmar or plantar skin surfaces. Corns form when the pressure point against the skin traces an elliptical or semi-elliptical path, the center of which is at the point of pressure, gradually widening. If there is constant stimulation of the tissues producing the corns, even after the corn is removed or the pressure surgically removed, the skin may continue to grow as a corn.
The name corn comes from its appearance under the microscope. The hard part at the center of the corn resembles a barley hare, that is, a funnel with a broad raised top and a pointed bottom. "Corn" used to be a generic term for grain, and the name stuck. The scientific name is heloma. Hard corns are called heloma durum, while soft corns are called heloma molle.
The place of occurrence differentiates between soft and hard corns. Hard corns occur on dry, flat surfaces of skin. Soft corns (frequently found between adjacent toes) stay moist, keeping the surrounding skin soft. The corn's center is not soft, however, but indurated.
# Development
Although usually found on the foot (where the most pressure occurs), calluses can occur anywhere on the body as a reaction to moderate, constant "grinding" pressure. It is the natural reaction of the palmar or plantar skin.
For example, players of string instruments will develop calluses on their fingers with frequent play. This actually helps the player as the thicker skin protects the fingertips - extended play is often painful before the calluses appear. If a beginning player plays too hard, or with an extended amount of left- (especially) or right-hand pizzicato, however, a blister may be produced instead.
Drummers can also develop a callus on their feet and hands. Calluses on the feet are more common in metal drummers, where double bass drumming is used more often. Use of older sticks will also cause callus on the palms and fingers of a drummer.
People with bunions may find painful calluses behind the second or third toe. These are caused by unequal pressure placed on the smaller toes. Such pressure-induced calluses can be very painful and often do not respond to trimming of the callus, soft materials, or orthotic devices. It is not the callus that causes pain, but rather the severe imbalance in the function of the foot that is taking its toll.
Shoes can produce corns by rubbing against the top of the toes or foot. Continued irritation may cause pain. Stretching the rubbing area of the shoe may reduce the pressure and stop the pain, but the corn may remain. If a toenail or a fingernail rubs against the skin, pinching it between surfaces for a period of time, a corn can form at the edge of the nail. These are difficult to treat because frequently the nail is the primary cause.
Sometimes a callus occurs where there is no rubbing or pressure. These hyperkeratoses can have a variety of causes. Some toxins, such as arsenic, can cause thick palms and soles. Some diseases, such as syphilis, can cause thickening of the palms and soles as well as pinpoint hyperkeratoses. There is a benign condition called keratosis palmaris et plantaris, which produces corns in the creases of the fingers and non-weight-bearing spaces of the feet. Some of this may be caused by actinic keratosis, which occurs due to overexposure to sun, or with age and hormonal shifts.
# Diagnosis
## Physical Examination
### Skin
- Callus. Adapted from Dermatology Atlas.[1]
- Callus. Adapted from Dermatology Atlas.[1]
- Callus. Adapted from Dermatology Atlas.[1]
- Lip callosity. Adapted from Dermatology Atlas.[1]
- Lip callosity. Adapted from Dermatology Atlas.[1]
# Treatment
A common method, often done by a podiatrist, is to shave the calluses down, and perhaps pad them.[citation needed]
For calluses on the feet an inexpensive home remedy is to dissolve a foot soap powder composed of borax, iodine and bran in warm water and soak the feet in the solution for 15 to 20 minutes. This softens the calluses so that layers of dead skin can be rubbed away with a cloth towel. Repeated soaking over a period of several days can often allow removal of even the core with nothing more than the friction of the cloth towel. If this fails, use of a pumice stone can also remove the skin.
Most corns and calluses located under the foot are caused by the pressure of the foot bones against the skin, preventing it from moving with the shoe or the ground. While well-fitting shoes will help some of these problems, occasionally some other degree of intervention is required to completely rid the foot of the problem. The most basic treatment is to put a friction-reducing insole or material into the shoe, or against the foot. In some cases, this will reduce the painfulness without actually making the callus go away.
In many situations, a change in the function of the foot by use of an orthotic device is required. This reduces friction and pressure, allowing the skin to rest and to stop forming protective skin coverings.
Salicylic acid (0.5%-40%) can be used for two reasons, "(1) it decreases keratinocyte adhesion, and (2) it increases water binding which leads to hydration of the keratin." [2]
Using a knife to cut it away is dangerous because it can result in bleeding of the foot and infection.
At other times, surgical correction of the pressure is needed.
# Diabetes
People with diabetes face special skin challenges. Because diabetes affects the capillaries, the small vessels which feed the skin its blood supply, thickening of the skin increases the difficulty to supply nutrients to the skin. Additionally, the shear and pressure forces that cause corns and calluses may tear the capillaries, causing bleeding within the callus or corn.
Often, bleeding within the calluses is an early sign of diabetes, even before elevated blood sugars. Although the bleeding can be small, sometimes small pools of blood or hematoma are formed. The blood itself is an irritant, a foreign body within the callus that makes the area burn or itch. If the pool of blood is exposed to the outside, infection may follow. Infection may lead to ulceration. Luckily, this process can be prevented at several places, but such infections can become life-threatening. Diabetic foot infections are the leading cause of diabetic limb amputation. | https://www.wikidoc.org/index.php/Callosities | |
4c100b9fce3157addb24f0c3060ab2076805b954 | wikidoc | Calpol | Calpol
Calpol is a brand of children's medicine sold in the UK, Ireland and India. The main product is a paracetamol suspension. It is usually a coloured syrup with a sweet taste, used to treat fever and pain. Calpol also comes in a form containing ibuprofen, marketed under the name Calprofen.
In the UK, Calpol is widely available in most pharmacies and supermarkets.
The name Calpol is commonly used to refer to any pediatric paracetamol suspension and could be considered a Genericized Trademark
Calpol comes in 5 age ranges:
- 0-5 Months (containing 0.5mg of paracetamol per sachet)
- 5-12 Months (containing 30mg of paracetamol per sachet)
- 1-2 Years (containing 50mg of paracetamol per sachet)
- 3-5 Years (containing 70mg of paracetamol per sachet)
- 6+ Years (containing 150mg of paracetamol per sachet)
Calpol also comes in tablet form and in sachets. | Calpol
Calpol is a brand of children's medicine sold in the UK, Ireland and India. The main product is a paracetamol suspension. It is usually a coloured syrup with a sweet taste, used to treat fever and pain. Calpol also comes in a form containing ibuprofen, marketed under the name Calprofen.
In the UK, Calpol is widely available in most pharmacies and supermarkets.
The name Calpol is commonly used to refer to any pediatric paracetamol suspension and could be considered a Genericized Trademark
Calpol comes in 5 age ranges:
- 0-5 Months (containing 0.5mg of paracetamol per sachet)
- 5-12 Months (containing 30mg of paracetamol per sachet)
- 1-2 Years (containing 50mg of paracetamol per sachet)
- 3-5 Years (containing 70mg of paracetamol per sachet)
- 6+ Years (containing 150mg of paracetamol per sachet)
Calpol also comes in tablet form and in sachets.
# External links
- Official Calpol website
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Calpol | |
c59162be2f15474645ddbb88c1feb0d8122d3aac | wikidoc | Canola | Canola
Canola is a type of edible oil derived from plants initially bred in Canada by Keith Downey and Baldur Stefansson in the 1970s. The oil is extracted from a group of cultivars of rapeseed variants from which low erucic acid rapeseed oil and low glucosinolate meal are obtained. The word "canola" was derived from "Canadian oil, low acid" in 1978. The oil is also known as "LEAR" oil (for Low Erucic Acid Rapeseed).
# History
Once considered a specialty crop in Canada, canola has become a major North American cash crop. Canada and the United States produce between 7 and 10 million metric tons (tonnes) of canola seed per year. Annual Canadian exports total 3 to 4 million metric tons of the seed, 700,000 metric tons of canola oil and 1 million metric tons of canola meal. The United States is a net consumer of canola oil. The major customers of canola seed are Japan, Mexico, China and Pakistan, while the bulk of canola oil and meal goes to the United States, with smaller amounts shipped to Taiwan, Mexico, China, and Europe.
World production of rapeseed oil in the 2002–2003 season was about 14 million metric tons.
Canola was developed through conventional plant breeding from rapeseed, an oilseed plant with roots in ancient civilization. The word "rape" in rapeseed comes from the Latin word "rapum," meaning turnip. Turnip, rutabaga, cabbage, Brussels sprouts, mustard and many other vegetables are related to the two canola species commonly grown: Brassica napus and Brassica rapa. The negative associations with the word "rape" resulted in the more marketing-friendly name "Canola". The change in name also serves to distinguish it from regular rapeseed oil, which has much higher erucic acid content.
Hundreds of years ago, Asians and Europeans used rapeseed oil in lamps. As time progressed, people employed it as a cooking oil and added it to foods. Its use was limited until the development of steam power, when machinists found rapeseed oil clung to water or steam-washed metal surfaces better than other lubricants. World War II saw high demand for the oil as a lubricant for the rapidly increasing number of steam engines in naval and merchant ships. When the war blocked European and Asian sources of rapeseed oil, a critical shortage developed and Canada began to expand its limited rapeseed production.
After the war, demand declined sharply and farmers began to look for other uses for the plant and its products. Edible rapeseed oil extracts were first put on the market in 1956–1957, but these suffered from several unacceptable characteristics. Rapeseed oil had a distinctive taste and a disagreeable greenish colour due to the presence of chlorophyll. It also contained a high concentration of erucic acid. Experiments on animals have pointed to the possibility that erucic acid, consumed in large quantities, may cause heart damage, though Indian researchers have published findings that call into question these conclusions and the implication that the consumption of mustard or rapeseed oil is dangerous. Feed meal from the rapeseed plant was not particularly appealing to livestock, due to high levels of sharp-tasting compounds called glucosinolates.
Plant breeders in Canada, where rapeseed had been grown (mainly in Saskatchewan) since 1936, worked to improve the quality of the plant. In 1968 Dr Baldur Stefansson of the University of Manitoba used selective breeding to develop a variety of rapeseed low in erucic acid. In 1974 another variety was produced low in both erucic acid and glucosinolates; it was named Canola, from Canadian oil, low acid.
A variety developed in 1998 is considered to be the most disease- and drought-resistant variety of Canola to date. This and other recent varieties have been produced by gene splicing techniques.
An Oregon State University researcher has determined that growing winter canola for hybrid seed appears possible in central Oregon, USA. Canola is the highest-producing oil-seed crop, but the state prohibits it from being grown in Deschutes, Jefferson and Crook counties because it may attract bees away from specialty seed crops such as carrots which require bees for pollination.
Canola was originally a trademark but is now a generic term for this variety of oil. In Canada, an official definition of canola is codified in Canadian law.
# Health effects
Canola oil has been claimed to be healthy due to its very low, or even zero, saturated fat and high—almost 60%—monounsaturated oil content and beneficial omega-3 fatty acids profile. The Canola Council of Canada states that it is completely safe and is the healthiest of all commonly used cooking oils. Claims of safety are a bit questionable as almost all the testing on humans was based on trials that lasted an average of three weeks. Traditional rapeseed oil contains higher amounts of erucic acid and glucosinolates than the commercially-sold consumer variety, both of which were deemed undesirable for human consumption by the United States Food and Drug Administration (FDA). Erucic acid may be invovled with cancer and rancidity and glucosinolates may be goitrogenic. Canola oil contains only 0.5 to 1% erucic acid, well below the 2 percent limit set by the USDA.
For many years rapeseed oil was used for human consumption in Canada despite the possible undesirable effects of glucosinolates and erucic acid, which were considered to be acceptable due the health benefits of the oil. Researchers were later able to develop "double-zero" varieties by the 1980s without significant levels of erucic acid or glucosinolates.
Nonetheless, controversy continued, with an article implicating Canola oil with glaucoma and Mad Cow Disease. This article was taken up, condensed and widely circulated in a story via email. The industry and many health professionals condemn this as an email hoax making wholly unsubstantiated claims.
# Genetic modification
Genetically modified canola which is resistant to herbicide was first introduced to Canada in 1995. Today 80% of the acreage of canola is sown with genetically modified canola.
Contamination of conventional canola crops from neighbouring genetically engineered fields has been a serious problem for Canadian canola farmers. It is very difficult for farmers to grow non-GM crops because of the frequent contamination.
The most high-profile case of contamination is Monsanto Canada Inc. v. Schmeiser, where Monsanto sued Percy Schmeiser for patent infringement because his field was contaminated with Monsanto's patented roundup ready canola. The supreme court ruled that Percy was in violation of Monsanto's patent because the crops were growing on his land, but he was not required to pay Monsanto damages since he did not benefit financially from its presence. On March 19, 2008, Schmeiser and Monsanto Canada Inc came to an out of court settlement whereby Monsanto will pay for the clean-up costs of the contamination which came to a total of 660$ canadian. Also part of the agreement was that there was no gag-order on the settlement and that Monsanto could be sued again if any further contamination occurred.
Introduction of the genetically modified crop to Australia is generating considerable controversy. Canola is Australia's third biggest crop, and is often used by wheat farmers as a break crop to improve soil quality. As of 2008 the only genetically modified crops in Australia were non-food crops: carnations and cotton. In 2003, Australia's gene technology regulator approved the release of canola altered to make it resistant to the herbicide Glufosinate ammonium.
# Other facts
- 82% of the Canola crops planted in Alberta, Manitoba, and Saskatchewan are GM (genetically modified food) herbicide-tolerant varieties.
- In 2004, North Dakota produced 91% of the Canola in the United States.
- The rapeseed blossom is a major source of nectar for honeybees.
- Canola oil is a promising source for manufacturing biodiesel, a renewable alternative to fossil fuels.
- The main price-discovery mechanism for worldwide canola trade is the Winnipeg Commodity Exchange canola futures contract. Rapeseed is traded on the Euronext exchange.
- The oil is a central component of the The Shangri-La Diet. | Canola
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]
Canola is a type of edible oil derived from plants initially bred in Canada by Keith Downey and Baldur Stefansson in the 1970s. The oil is extracted from a group of cultivars of rapeseed variants from which low erucic acid rapeseed oil and low glucosinolate meal are obtained. The word "canola" was derived from "Canadian oil, low acid" in 1978.[1][2] The oil is also known as "LEAR" oil (for Low Erucic Acid Rapeseed).[3]
# History
Once considered a specialty crop in Canada, canola has become a major North American cash crop. Canada and the United States produce between 7 and 10 million metric tons (tonnes) of canola seed per year. Annual Canadian exports total 3 to 4 million metric tons of the seed, 700,000 metric tons of canola oil and 1 million metric tons of canola meal. The United States is a net consumer of canola oil. The major customers of canola seed are Japan, Mexico, China and Pakistan, while the bulk of canola oil and meal goes to the United States, with smaller amounts shipped to Taiwan, Mexico, China, and Europe.
World production of rapeseed oil in the 2002–2003 season was about 14 million metric tons.[4]
Canola was developed through conventional plant breeding from rapeseed, an oilseed plant with roots in ancient civilization. The word "rape" in rapeseed comes from the Latin word "rapum," meaning turnip. Turnip, rutabaga, cabbage, Brussels sprouts, mustard and many other vegetables are related to the two canola species commonly grown: Brassica napus and Brassica rapa. The negative associations with the word "rape" resulted in the more marketing-friendly name "Canola". The change in name also serves to distinguish it from regular rapeseed oil, which has much higher erucic acid content.
Hundreds of years ago, Asians and Europeans used rapeseed oil in lamps. As time progressed, people employed it as a cooking oil and added it to foods. Its use was limited until the development of steam power, when machinists found rapeseed oil clung to water or steam-washed metal surfaces better than other lubricants. World War II saw high demand for the oil as a lubricant for the rapidly increasing number of steam engines in naval and merchant ships. When the war blocked European and Asian sources of rapeseed oil, a critical shortage developed and Canada began to expand its limited rapeseed production.
After the war, demand declined sharply and farmers began to look for other uses for the plant and its products. Edible rapeseed oil extracts were first put on the market in 1956–1957, but these suffered from several unacceptable characteristics. Rapeseed oil had a distinctive taste and a disagreeable greenish colour due to the presence of chlorophyll. It also contained a high concentration of erucic acid. Experiments on animals have pointed to the possibility that erucic acid, consumed in large quantities, may cause heart damage, though Indian researchers have published findings that call into question these conclusions and the implication that the consumption of mustard or rapeseed oil is dangerous.[5][6][7][8][9] Feed meal from the rapeseed plant was not particularly appealing to livestock, due to high levels of sharp-tasting compounds called glucosinolates.
Plant breeders in Canada, where rapeseed had been grown (mainly in Saskatchewan) since 1936, worked to improve the quality of the plant. In 1968 Dr Baldur Stefansson of the University of Manitoba used selective breeding to develop a variety of rapeseed low in erucic acid. In 1974 another variety was produced low in both erucic acid and glucosinolates; it was named Canola, from Canadian oil, low acid.
A variety developed in 1998 is considered to be the most disease- and drought-resistant variety of Canola to date. This and other recent varieties have been produced by gene splicing techniques.
An Oregon State University researcher has determined that growing winter canola for hybrid seed appears possible in central Oregon, USA. Canola is the highest-producing oil-seed crop, but the state prohibits it from being grown in Deschutes, Jefferson and Crook counties because it may attract bees away from specialty seed crops such as carrots which require bees for pollination.
Canola was originally a trademark but is now a generic term for this variety of oil. In Canada, an official definition of canola is codified in Canadian law.[10]
# Health effects
Canola oil has been claimed to be healthy due to its very low, or even zero, saturated fat and high—almost 60%—monounsaturated oil content and beneficial omega-3 fatty acids profile. The Canola Council of Canada states that it is completely safe and is the healthiest of all commonly used cooking oils.[12] Claims of safety are a bit questionable as almost all the testing on humans was based on trials that lasted an average of three weeks.[13] Traditional rapeseed oil contains higher amounts of erucic acid and glucosinolates than the commercially-sold consumer variety, both of which were deemed undesirable for human consumption by the United States Food and Drug Administration (FDA). Erucic acid may be invovled with cancer and rancidity and glucosinolates may be goitrogenic.[citation needed] Canola oil contains only 0.5 to 1% erucic acid, well below the 2 percent limit set by the USDA.[14]
For many years rapeseed oil was used for human consumption in Canada despite the possible undesirable effects of glucosinolates and erucic acid, which were considered to be acceptable due the health benefits of the oil. Researchers were later able to develop "double-zero" varieties by the 1980s without significant levels of erucic acid or glucosinolates.[citation needed]
Nonetheless, controversy continued, with an article implicating Canola oil with glaucoma and Mad Cow Disease.[15] This article was taken up, condensed and widely circulated in a story via email. The industry and many health professionals condemn this as an email hoax making wholly unsubstantiated claims.[16]
# Genetic modification
Genetically modified canola which is resistant to herbicide was first introduced to Canada in 1995. Today 80% of the acreage of canola is sown with genetically modified canola.[17]
Contamination of conventional canola crops from neighbouring genetically engineered fields has been a serious problem for Canadian canola farmers. It is very difficult for farmers to grow non-GM crops because of the frequent contamination.
The most high-profile case of contamination is Monsanto Canada Inc. v. Schmeiser, where Monsanto sued Percy Schmeiser for patent infringement because his field was contaminated with Monsanto's patented roundup ready canola. The supreme court ruled that Percy was in violation of Monsanto's patent because the crops were growing on his land, but he was not required to pay Monsanto damages since he did not benefit financially from its presence.[18] On March 19, 2008, Schmeiser and Monsanto Canada Inc came to an out of court settlement whereby Monsanto will pay for the clean-up costs of the contamination which came to a total of 660$ canadian. Also part of the agreement was that there was no gag-order on the settlement and that Monsanto could be sued again if any further contamination occurred.[19]
Introduction of the genetically modified crop to Australia is generating considerable controversy.[20] Canola is Australia's third biggest crop, and is often used by wheat farmers as a break crop to improve soil quality. As of 2008 the only genetically modified crops in Australia were non-food crops: carnations and cotton. In 2003, Australia's gene technology regulator approved the release of canola altered to make it resistant to the herbicide Glufosinate ammonium.[21]
# Other facts
- 82% of the Canola crops planted in Alberta, Manitoba, and Saskatchewan are GM (genetically modified food) herbicide-tolerant varieties.[22]
- In 2004, North Dakota produced 91% of the Canola in the United States.[23]
- The rapeseed blossom is a major source of nectar for honeybees.
- Canola oil is a promising source for manufacturing biodiesel, a renewable alternative to fossil fuels.
- The main price-discovery mechanism for worldwide canola trade is the Winnipeg Commodity Exchange canola futures contract. Rapeseed is traded on the Euronext exchange.
- The oil is a central component of the The Shangri-La Diet. | https://www.wikidoc.org/index.php/Canola | |
5b8b4cad2d39be363fb906d0fc97ad23f9f7d399 | wikidoc | Capsid | Capsid
# Overview
A capsid is the protein shell of a virus. It consists of several oligomeric subunits made of protein. The capsid encloses the genetic material of the virus.
Capsids are broadly classified according to their structure. The majority of viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while the helical shape is cylindrical. The capsid faces may consist of one or more proteins. For example, the foot-and-mouth disease virus capsid has faces consisting of three proteins named VP1-3.
Some viruses are enveloped, meaning that the capsid is coated with a lipid membrane known as the viral envelope. The envelope is acquired by the capsid from an intracellular membrane; some examples would include the inner nuclear membrane, the golgi membrane, or the cell's outer membrane.
Once the virus has infected the cell, it will start replicating itself, using the mechanisms of the infected host cell. During this process, new capsid subunits are synthesized according to the genetic material of the virus, using the protein biosynthesis mechanism of the cell. During the assembly process, a portal subunit is assembled at one vertex of the capsid. Through this portal, viral DNA or RNA is transported into the capsid. The structure and assembly of the Herpes virus Capsid Portal Protein has been imaged via cryo-electron microscopy.
Structural analyses of major capsid protein (MCP) architectures have been used to categorise viruses into families. For example, the bacteriophage PRD1, Paramecium bursaria Chlorella algal virus, and mammalian adenovirus have been placed in the same family.
# Notes
- ↑ Branden, Carl and Tooze, John (1991). Introduction to Protein Structure. pp. 161–162. ISBN 0-8153-0270-3.CS1 maint: Multiple names: authors list (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ "Virus Structure (web-books.com)".
- ↑ Alberts, Bruce; Bray, Dennis; Lewis, Julian; Raff, Martin; Roberts, Keith; Watson, James D. (1994). Molecular Biology of the Cell (4 ed.). p. 280.CS1 maint: Multiple names: authors list (link)
- ↑ Newcomb WW, Homa FL, Brown JC (2005 Aug). "Involvement of the portal at an early step in herpes simplex virus capsid assembly". Journal of Virology. 79 (16): 10540-6. PMID 16051846. Check date values in: |date= (help)CS1 maint: Multiple names: authors list (link)
Cardone G, Winkler DC, Trus BL, Cheng N, Heuser JE, Newcomb WW, Brown JC, Steven AC (2007 May 10). "Visualization of the herpes simplex virus portal in situ by cryo-electron tomography". Virology. 361 (2): 426-34. PMID 17188319. Check date values in: |date= (help)CS1 maint: Multiple names: authors list (link)
- ↑ Khayat et al. classified Sulfolobus turreted icosahedral virus (STIV) and Laurinmäki et al. classified bacteriophage Bam35 - Proc. Natl. Acad. Sci. U.S.A. 103, 3669 (2006); 102, 18944 (2005); Structure 13, 1819 (2005)
ca:Càpsida
de:Kapsid
it:Capside
nl:Eiwitmantel | Capsid
# Overview
A capsid is the protein shell of a virus. It consists of several oligomeric subunits made of protein. The capsid encloses the genetic material of the virus.
Capsids are broadly classified according to their structure. The majority of viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while the helical shape is cylindrical.[1] The capsid faces may consist of one or more proteins. For example, the foot-and-mouth disease virus capsid has faces consisting of three proteins named VP1-3.[2]
Some viruses are enveloped, meaning that the capsid is coated with a lipid membrane known as the viral envelope. The envelope is acquired by the capsid from an intracellular membrane; some examples would include the inner nuclear membrane, the golgi membrane, or the cell's outer membrane.[3]
Once the virus has infected the cell, it will start replicating itself, using the mechanisms of the infected host cell. During this process, new capsid subunits are synthesized according to the genetic material of the virus, using the protein biosynthesis mechanism of the cell. During the assembly process, a portal subunit is assembled at one vertex of the capsid. Through this portal, viral DNA or RNA is transported into the capsid.[4] The structure and assembly of the Herpes virus Capsid Portal Protein has been imaged via cryo-electron microscopy.[5]
Structural analyses of major capsid protein (MCP) architectures have been used to categorise viruses into families. For example, the bacteriophage PRD1, Paramecium bursaria Chlorella algal virus, and mammalian adenovirus have been placed in the same family.[6]
# Notes
- ↑ Branden, Carl and Tooze, John (1991). Introduction to Protein Structure. pp. 161–162. ISBN 0-8153-0270-3.CS1 maint: Multiple names: authors list (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ "Virus Structure (web-books.com)".
- ↑ Alberts, Bruce; Bray, Dennis; Lewis, Julian; Raff, Martin; Roberts, Keith; Watson, James D. (1994). Molecular Biology of the Cell (4 ed.). p. 280.CS1 maint: Multiple names: authors list (link)
- ↑ Newcomb WW, Homa FL, Brown JC (2005 Aug). "Involvement of the portal at an early step in herpes simplex virus capsid assembly". Journal of Virology. 79 (16): 10540-6. PMID 16051846. Check date values in: |date= (help)CS1 maint: Multiple names: authors list (link)
- ↑
Cardone G, Winkler DC, Trus BL, Cheng N, Heuser JE, Newcomb WW, Brown JC, Steven AC (2007 May 10). "Visualization of the herpes simplex virus portal in situ by cryo-electron tomography". Virology. 361 (2): 426-34. PMID 17188319. Check date values in: |date= (help)CS1 maint: Multiple names: authors list (link)
- ↑ Khayat et al. classified Sulfolobus turreted icosahedral virus (STIV) and Laurinmäki et al. classified bacteriophage Bam35 - Proc. Natl. Acad. Sci. U.S.A. 103, 3669 (2006); 102, 18944 (2005); Structure 13, 1819 (2005)
ca:Càpsida
de:Kapsid
it:Capside
nl:Eiwitmantel
Template:WS | https://www.wikidoc.org/index.php/Capsid | |
1fd26805a944794abcbbb5dc4db850588e1c0531 | wikidoc | Phenol | Phenol
Please Take Over This Page and Apply to be Editor-In-Chief for this topic:
There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
# Overview
Phenol, also known under an older name of carbolic acid, is a toxic, colourless crystalline solid with a sweet tarry odor. Its chemical formula is C6H5OH and its structure is that of a hydroxyl group (-OH) bonded to a phenyl ring; it is thus an aromatic compound.
# Phenols
The word phenol is also used to refer to any compound which contains a six-membered aromatic ring, bonded directly to a hydroxyl group (-OH). In effect, phenols are a class of organic compounds of which the phenol discussed in this article is the simplest member.
# Properties
Phenol has a limited solubility in water (8.3 g/100 ml). It is slightly acidic: the phenol molecule has weak tendencies to lose the H+ ion from the hydroxyl group, resulting in the highly water-soluble phenoxide anion C6H5O−. Compared to aliphatic alcohols, phenol shows much higher acidity; it even reacts with aqueous NaOH to lose H+, whereas aliphatic alcohols do not. One explanation for the increased acidity is resonance stabilization of the phenoxide anion by the aromatic ring. In this way, the negative charge on oxygen is shared by the ortho and para carbon atoms. In another explanation, increased acidity is the result of orbital overlap between the oxygen's lone pairs and the aromatic system. In a third, the dominant effect is the induction from the sp² hybridized carbons; the comparatively more powerful inductive withdrawal of electron density that is provided by the sp² system compared to an sp³ system allows for great stabilization of the oxyanion. In making this conclusion, one can examine the pKa of the enol of acetone, which is 10.9 in comparison to phenol with a pKa of 10.0.
# Production
Phenol can be made from the partial oxidation of benzene or benzoic acid, by the cumene process, or by the Raschig process. It can also be found as a product of coal oxidation.
# Uses
Phenol has antiseptic properties, and was used by Sir Joseph Lister (1827-1912) in his pioneering technique of antiseptic surgery, though the skin irritation caused by continual exposure to phenol eventually led to the substitution of aseptic (germ-free) techniques in surgery. (In fact, surgical gloves were first used to protect doctor's hands from phenol burns.) It is also the active ingredient in some oral anesthetics such as Chloraseptic spray. Phenol was also the main ingredient of the Carbolic Smoke Ball, a device sold in London designed to protect the user against influenza and other ailments. In the early part of the 20th century, it was used in the Battle Creek Sanitarium to discourage female masturbation.
It is also used in the production of drugs (it is the starting material in the industrial production of aspirin), weedkiller, and synthetic resins (Bakelite, one of the first synthetic resins to be manufactured, is a polymer of phenol with formaldehyde). Exposure of the skin to concentrated phenol solutions causes chemical burns which may be severe; in laboratories where it is used, it is usually recommended that polyethylene glycol solution is kept available for washing off splashes. Washing with large amounts of plain water (most labs have a safety shower or eye-wash) and removal of contaminated clothing are required, and immediate ER treatment for large splashes; particularly if the phenol is mixed with chloroform (a commonly used mixture in molecular biology for DNA purification). Notwithstanding the effects of concentrated solutions, it is also used in cosmetic surgery as an exfoliant, to remove layers of dead skin. It is also used in phenolization, a surgical procedure used to treat an ingrown nail, in which it is applied to the toe to prevent regrowth of nails.
Injections of phenol have occasionally been used as a means of rapid execution. In particular, phenol was used as a means of extermination by the Nazis during the Second World War. Phenol injections were given to thousands of people in concentration camps, especially at Auschwitz-Birkenau. Injections were administered either by medical doctors or by their assistants; such injections were originally given intravenously, more commonly in the arm, but injection directly into the heart, so as to induce nearly instant death, was later preferred. One of the most famous inmates at Auschwitz to be murdered by carbolic acid injection was St. Maximilian Kolbe, a Catholic priest who volunteered to undergo three weeks of starvation and dehydration in the place of another inmate and who was finally injected with carbolic acid so that the Nazis could make more room in their holding cells.
A use of phenol in molecular biology is the separation of genetic material (nucleic acids) (DNA & RNA) from proteins.
# Hydrothermal chemistry
Under laboratory conditions mimicking hydrothermal circulation (water, 200°C, 1.9 GPa), phenol is found to form from sodium hydrogen carbonate and iron powder (1.8% chemical yield). This discovery made in 2007 may be relevant to the origin of life question as phenol is a fragment of the biomolecule tyrosine. | Phenol
Template:Chembox new
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]
Please Take Over This Page and Apply to be Editor-In-Chief for this topic:
There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [3] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
# Overview
Phenol, also known under an older name of carbolic acid, is a toxic, colourless crystalline solid with a sweet tarry odor. Its chemical formula is C6H5OH and its structure is that of a hydroxyl group (-OH) bonded to a phenyl ring; it is thus an aromatic compound.
# Phenols
The word phenol is also used to refer to any compound which contains a six-membered aromatic ring, bonded directly to a hydroxyl group (-OH). In effect, phenols are a class of organic compounds of which the phenol discussed in this article is the simplest member.
# Properties
Phenol has a limited solubility in water (8.3 g/100 ml). It is slightly acidic: the phenol molecule has weak tendencies to lose the H+ ion from the hydroxyl group, resulting in the highly water-soluble phenoxide anion C6H5O−. Compared to aliphatic alcohols, phenol shows much higher acidity; it even reacts with aqueous NaOH to lose H+, whereas aliphatic alcohols do not. One explanation for the increased acidity is resonance stabilization of the phenoxide anion by the aromatic ring. In this way, the negative charge on oxygen is shared by the ortho and para carbon atoms[1]. In another explanation, increased acidity is the result of orbital overlap between the oxygen's lone pairs and the aromatic system[2]. In a third, the dominant effect is the induction from the sp² hybridized carbons; the comparatively more powerful inductive withdrawal of electron density that is provided by the sp² system compared to an sp³ system allows for great stabilization of the oxyanion. In making this conclusion, one can examine the pKa of the enol of acetone, which is 10.9 in comparison to phenol with a pKa of 10.0.[3]
# Production
Phenol can be made from the partial oxidation of benzene or benzoic acid, by the cumene process, or by the Raschig process. It can also be found as a product of coal oxidation.
# Uses
Phenol has antiseptic properties, and was used by Sir Joseph Lister (1827-1912) in his pioneering technique of antiseptic surgery, though the skin irritation caused by continual exposure to phenol eventually led to the substitution of aseptic (germ-free) techniques in surgery. (In fact, surgical gloves were first used to protect doctor's hands from phenol burns.) It is also the active ingredient in some oral anesthetics such as Chloraseptic spray. Phenol was also the main ingredient of the Carbolic Smoke Ball, a device sold in London designed to protect the user against influenza and other ailments. In the early part of the 20th century, it was used in the Battle Creek Sanitarium to discourage female masturbation.[4]
It is also used in the production of drugs (it is the starting material in the industrial production of aspirin), weedkiller, and synthetic resins (Bakelite, one of the first synthetic resins to be manufactured, is a polymer of phenol with formaldehyde). Exposure of the skin to concentrated phenol solutions causes chemical burns which may be severe; in laboratories where it is used, it is usually recommended that polyethylene glycol solution is kept available for washing off splashes. Washing with large amounts of plain water (most labs have a safety shower or eye-wash) and removal of contaminated clothing are required, and immediate ER treatment for large splashes; particularly if the phenol is mixed with chloroform (a commonly used mixture in molecular biology for DNA purification). Notwithstanding the effects of concentrated solutions, it is also used in cosmetic surgery as an exfoliant, to remove layers of dead skin. It is also used in phenolization, a surgical procedure used to treat an ingrown nail, in which it is applied to the toe to prevent regrowth of nails.
Injections of phenol have occasionally been used as a means of rapid execution. In particular, phenol was used as a means of extermination by the Nazis during the Second World War. Phenol injections were given to thousands of people in concentration camps, especially at Auschwitz-Birkenau. Injections were administered either by medical doctors or by their assistants; such injections were originally given intravenously, more commonly in the arm, but injection directly into the heart, so as to induce nearly instant death, was later preferred. One of the most famous inmates at Auschwitz to be murdered by carbolic acid injection was St. Maximilian Kolbe, a Catholic priest who volunteered to undergo three weeks of starvation and dehydration in the place of another inmate and who was finally injected with carbolic acid so that the Nazis could make more room in their holding cells.[5]
A use of phenol in molecular biology is the separation of genetic material (nucleic acids) (DNA & RNA) from proteins.
# Hydrothermal chemistry
Under laboratory conditions mimicking hydrothermal circulation (water, 200°C, 1.9 GPa), phenol is found to form from sodium hydrogen carbonate and iron powder (1.8% chemical yield)[6]. This discovery made in 2007 may be relevant to the origin of life question as phenol is a fragment of the biomolecule tyrosine. | https://www.wikidoc.org/index.php/Carbolic_Acids_and_Anhydrides | |
d6f4566731e88fa33d7cb3699bc5ea990752a226 | wikidoc | Carbon | Carbon
Carbon (Template:PronEng) is a chemical element with the symbol C and atomic number 6. It is a group 14, nonmetallic, tetravalent element, that presents several allotropic forms of which the best known are graphite (the thermodynamically stable form under normal conditions), diamond, and amorphous carbon. There are three naturally occurring isotopes: 12C and 13C are stable, and 14C is radioactive, decaying with a half-life of about 5700 years. Carbon is one of the few elements known to man since antiquity. The name "carbon" comes from Latin language carbo, coal, and in some Romance languages, the word carbon can refer both to the element and to coal.
It is the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body it is the second most abundant element by mass (about 18.5%) after oxygen. This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.
The physical properties of carbon vary widely with the allotropic form. For example, diamond is highly transparent, while graphite is opaque and black. Diamond is among the hardest materials known, while graphite is soft enough to form a streak on paper. Diamond has a very low electric conductivity, while graphite is a very good conductor. Also, diamond has the highest thermal conductivity of all known materials under normal conditions. All the allotropic forms are solids under normal conditions.
All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil and methane clathrates. Carbon forms more compounds than any other element, with almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such compounds that are theoretically possible under standard conditions.
# Characteristics
Carbon exhibits remarkable properties, some paradoxical. Its different forms or allotropes (see below) include the hardest naturally occurring substance (diamond) and also one of the softest substances (graphite) known. Moreover, it has a great affinity for bonding with other small atoms, including other carbon atoms, and is capable of forming multiple stable covalent bonds with such atoms. Because of these properties, carbon is known to form nearly ten million different compounds, the large majority of all chemical compounds. Moreover, carbon has the highest melting/sublimation point of all elements. At atmospheric pressure it has no actual melting point as its triple point is at 10 MPa (100 bar) so it sublimates above 4000 K. Carbon sublimes in a carbon arc which has a temperature of about 5800K. Thus irrespective of its allotropic form, carbon remains solid at higher temperatures than the highest melting point metals such as tungsten or rhenium. Although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature.
Carbon compounds form the basis of all life on Earth and the carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. Although it forms an extraordinary variety of compounds, most forms of carbon are comparatively unreactive under normal conditions. At standard temperature and pressure, it resists all but the strongest oxidizers. It does not react with sulfuric acid, hydrochloric acid, chlorine or any alkalis. At elevated temperatures carbon reacts with oxygen to form carbon oxides, and will reduce such metal oxides as iron oxide to the metal. This exothermic reaction is used in the iron and steel industry to control the carbon content of steel:
Fe3O4 + 4C(s) → 3Fe(s) + 4CO(g)
with sulfur to form carbon disulfide and with steam in the coal-gas reaction
C(s) + H2O(g) → CO(g) + H2(g).
Carbon combines with some metals at high temperatures to form metallic carbides, such as the iron carbide cementite in steel, and tungsten carbide, widely used as an abrasive and for making hard tips for cutting tools.
The system of carbon allotropes spans a range of extremes:
## Allotropes
Atomic carbon is a very short-lived specie and therefore, carbon is stabilized in various multi-atomic structures with different molecular configurations called allotropes. The three relatively well-known allotropes of carbon are amorphous carbon, graphite, and diamond. Once considered exotic, fullerenes are nowadays commonly synthesized and used in research; they include buckyballs, carbon nanotubes, carbon nanobuds and nanofibers,. Several other exotic allotropes have also been discovered, such as aggregated diamond nanorods, lonsdaleite, glassy carbon, carbon nanofoam and linear acetylenic carbon.
- The amorphous form, is an assortment of carbon atoms in a non-crystalline, irregular, glassy state, which is essentially graphite but not held in a crystalline macrostructure. It is present as a powder, and is the main constituent of substances such as charcoal, lampblack (soot) and activated carbon.
- At normal pressures carbon takes the form of graphite, in which each atom is bonded trigonally to three others in a plane composed of fused hexagonal rings, just like those in aromatic hydrocarbons. The resulting network is 2-dimensional, and the resulting flat sheets are stacked and loosely bonded through weak Van der Waals forces. This gives graphite its softness and its cleaving properties (the sheets slip easily past one another). Because of the delocalization of one of the outer electrons of each atom to form a π-cloud, graphite conducts electricity, but only in the plane of each covalently bonded sheet. This results in a lower bulk electrical conductivity for carbon than for most metals. The delocalization also accounts for the energetic stability of graphite over diamond at room temperature.
- At very high pressures carbon forms the more compact allotrope diamond, having nearly twice the density of graphite. Here, each atom is bonded tetrahedrally to four others, thus making a 3-dimensional network of puckered six-membered rings of atoms. Diamond has the same cubic structure as silicon and germanium and, thanks to the strength of the carbon-carbon bonds is the hardest naturally occurring substance in terms of resistance to scratching. Contrary to the popular belief that "diamonds are forever", they are in fact thermodynamically unstable under normal conditions and transform into graphite. But due to a high activation energy barrier, the transition into graphite is so extremely slow at room temperature as to be unnoticeable. Under some conditions, carbon crystallizes as Lonsdaleite, a form similar to diamond but forming a hexagonal crystal lattice.
- Fullerenes have a graphite-like structure, but instead of purely hexagonal packing, they also contain pentagons (or even heptagons) of carbon atoms, which bend the sheet into spheres, ellipses or cylinders. The properties of fullerenes (split into buckyballs, buckytubes and nanobuds) have not yet been fully analyzed and represents an intense are of research in nanomaterials. The name "fullerene" is given after Richard Buckminster Fuller, developer of some geodesic domes, which resemble the structure of fullerenes. The buckyballs are fairly large molecules formed completely of carbon bonded trigonally, forming spheroids (the best-known and simplest is the soccerball-shaped structure C60 buckminsterfullerene). Carbon nanotubes are structurally similar to buckyballs, except that each atom is bonded trigonally in a curved sheet that forms a hollow cylinder. Nanobuds were first published in 2007 and are hybrid bucky tube/buckyball materials (buckyballs are covalently bonded to the outer wall of a nanotube) that combine the properties of both in a single structure.
- Of the other discovered allotropes, aggregated diamond nanorods have been synthesised in 2005 and are believed to be the hardest substance known yet. Carbon nanofoam is a ferromagnetic allotrope discovered in 1997. It consists of a low-density cluster-assembly of carbon atoms strung together in a loose three-dimensional web, in which the atoms are bonded trigonally in six- and seven-membered rings. It is among the lightest known solids, with a density of about 2 kg/m³. Similarly, glassy carbon contains a high proportion of closed porosity. But unlike normal graphite, the graphitic layers are not stacked like pages in a book, but have a more random arrangement. Linear acetylenic carbon has the chemical structure -(C:::C)n- .Carbon in this modification is linear with sp orbital hybridisation, and is a polymer with alternating single and triple bonds. This type of carbyne is of considerable interest to nanotechnology as its Young's modulus is forty times that of the hardest known material - diamond.
## Occurrence
Carbon is the fourth most abundant chemical element in the universe by mass after hydrogen, helium, and oxygen. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. Some meteorites contain microscopic diamonds that were formed when the solar system was still a protoplanetary disk. Microscopic diamonds may also be formed by the intense pressure and high temperature at the sites of meteorite impacts.
In combination with oxygen in carbon dioxide, carbon is found in the Earth's atmosphere (in quantities of approximately 810 gigatonnes) and dissolved in all water bodies (approximately 36000 gigatonnes). Around 1900 gigatonnes are present in the biosphere. Hydrocarbons (such as coal, petroleum, and natural gas) contain carbon as well — coal "reserves" (not "resources") amount to around 900 gigatonnes, and oil reserves around 150 gigatonnes. With smaller amounts of calcium, magnesium, and iron, carbon is a major component of very large masses carbonate rock (limestone, dolomite, marble etc.).
Coal is a significant commercial source of mineral carbon; anthracite containing 92-98% carbon and the largest source (4000 Gt, or 80% of coal, gas and oil reserves) of carbon in a form suitable for use as fuel.
Graphite is found in large quantities in New York and Texas in the United States, Russia, Mexico, Greenland, and India.
Natural diamonds occur in the mineral kimberlite, found in ancient volcanic "necks," or "pipes". Most diamond deposits are in Africa, notably in South Africa, Namibia, Botswana, the Republic of the Congo, and Sierra Leone. There are also deposits in Arkansas, Canada, the Russian Arctic, Brazil and in Northern and Western Australia.
Carbon is also found in abundance in the Sun, stars, comets, and atmospheres of most planets. Diamonds are now also being recovered from the ocean floor off the Cape of Good Hope. About 30% of all industrial diamonds used in the U.S. are now made synthetically.
According to studies from the Massachusetts Institute of Technology, an estimate of the global carbon budget is:
Carbon-14 is formed in upper layers of the troposphere and the stratosphere, at altitudes of 9–15 km, by a reaction that is precipitated by cosmic rays. Thermal neutrons are produced that collide with the nuclei of nitrogen-14, forming carbon-14 and a proton.
## Isotopes
Isotopes of carbon are atomic nuclei that contain six protons plus a number of neutrons (varying from 2 to 16). Carbon has two stable, naturally occurring isotopes. The isotope carbon-12 (12C) forms 98.93% of the carbon on Earth, while carbon-13 (13C) forms the remaining 1.07%. The concentration of 12C is further increased in biological materials because biochemical reactions discriminate against 13C. In 1961 the International Union of Pure and Applied Chemistry (IUPAC) adopted the isotope carbon-12 as the basis for atomic weights. Identification of carbon in NMR experiments is done with the isotope 13C.
Carbon-14 (14C) is a naturally occurring radioisotope which occurs in trace amounts on Earth of up to 1 part per trillion (0.0000000001%), mostly confined to the atmosphere and superficial deposits, particularly of peat and other organic materials. This isotope decays by 0.158 MeV β- emission. Because of its relatively short half-life of 5730 years, 14C is virtually absent in ancient rocks, but is created in the upper atmosphere (lower stratosphere and upper troposphere) by interaction of nitrogen with cosmic rays. The abundance of 14C in the atmosphere and in living organisms is almost constant, but decreases predictably in their bodies after death. This principle is used in radiocarbon dating, discovered in 1949, which has been used extensively to determine the age of carbonaceous materials with ages up to about 40,000 years.
There are 15 known isotopes of carbon and the shortest-lived of these is 8C which decays through proton emission and alpha decay and has a half-life of 1.98739x10-21 s. The exotic 19C exhibits a nuclear halo, which means its radius is appreciably larger than would be expected if the nucleus was a sphere of constant density.
## Formation in stars
Formation of the carbon atomic nucleus requires a nearly simultaneous triple collision of alpha particles (helium nuclei) within the core of a giant or supergiant star. This happens in conditions of temperature and helium concentration that the rapid expansion and cooling of the early universe prohibited, and therefore no significant carbon was created during the Big Bang. Instead, the interiors of stars in the horizontal branch transform three helium nuclei into carbon by means of this triple-alpha process. In order to be available for formation of life as we know it, this carbon must then later be scattered into space as dust, in supernova explosions, as part of the material which later forms second- and third-generation star systems which have planets accreted from such dust. The Solar System is one such third-generation star system.
One of the fusion mechanisms powering stars is the carbon-nitrogen cycle.
Rotational transitions of various isotopic forms of carbon monoxide (e.g. 12CO, 13CO, and C18O) are detectable in the submillimeter regime, and are used in the study of newly forming stars in molecular clouds.
## Carbon cycle
Under terrestrial conditions, conversion of one element to another is very rare. Therefore, the amount of carbon on Earth is effectively constant. Thus, processes that use carbon must obtain it somewhere and dispose of it somewhere else. The paths that carbon follows in the environment make up the carbon cycle. For example, plants draw carbon dioxide out of their environment and use it to build biomass, as in carbon respiration or the Calvin cycle, a process of carbon fixation. Some of this biomass is eaten by animals, whereas some carbon is exhaled by animals as carbon dioxide. The carbon cycle is considerably more complicated than this short loop; for example, some carbon dioxide is dissolved in the oceans; dead plant or animal matter may become petroleum or coal, which can burn with the release of carbon, should bacteria not consume it.
# Compounds
## Inorganic compounds
Commonly carbon-containing compounds which are associated with minerals or which do not contain hydrogen or fluorine, are treated separately from classical organic compounds; however the definition is not rigid (see reference articles above). Among these are the simple oxides of carbon. The most prominent oxide is carbon dioxide (CO2). This was once the principal constituent of the paleoatmosphere, but is a minor component of the Earth's atmosphere today. Dissolved in water, it forms carbonic acid (H2CO3), but as most compounds with multiple single-bonded oxygens on a single carbon it is unstable. Through this intermediate, though, resonance-stabilized carbonate ions are produced. Some important minerals are carbonates, notably calcite. Carbon disulfide (CS2) is similar.
The other common oxide is carbon monoxide (CO). It is formed by incomplete combustion, and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly polar, resulting in a tendency to bind permanently to hemoglobin molecules, displacing oxygen, which has a lower binding affinity. Cyanide (CN–), has a similar structure, but behaves much like a halide ion (pseudohalogen). For example it can form the nitride cyanogen molecule ((CN)2), similar to diatomic halides. Other uncommon oxides are carbon suboxide (C3O2), the unstable dicarbon monoxide (C2O), and even carbon trioxide (CO3).
With reactive metals, such as tungsten, carbon forms either carbides (C4–), or acetylides (C22–) to form alloys with high melting points. These anions are also associated with methane and acetylene, both very weak acids. With an electronegativity of 2.5, carbon prefers to form covalent bonds. A few carbides are covalent lattices, like carborundum (SiC), which resembles diamond.
## Organic compounds
Carbon has the ability to form very long chains with interconnecting C-C bonds. This property is called catenation. Carbon-carbon bonds are strong, and stable. This property allows carbon to form an almost infinite number of compounds; in fact, there are more known carbon-containing compounds than all the compounds of the other chemical elements combined except those of hydrogen (because almost all organic compounds contain hydrogen too).
The simplest form of an organic molecule is the hydrocarbon—a large family of organic molecules that are composed of hydrogen atoms bonded to a chain of carbon atoms. Chain length, side chains and functional groups all affect the properties of organic molecules. By IUPAC's definition, all the other organic compounds are functionalized compounds of hydrocarbons.
Carbon occurs in all organic life and is the basis of organic chemistry. When united with hydrogen, it forms various flammable compounds called hydrocarbons which are important to industry as chemical feedstock for the manufacture of plastics, petrochemicals and as fossil fuels.
When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds including sugars, celluloses, lignans, chitins, alcohols, fats, and aromatic esters, carotenoids and terpenes. With nitrogen it forms alkaloids, and with the addition of sulfur also it forms antibiotics, amino acids and proteins. With the addition of phosphorus to these other elements, it forms DNA and RNA, the chemical codes of life, and adenosine triphosphate (ATP), the most important energy-transfer molecules in all living cells.
# History and etymology
The English name carbon comes from the Latin carbo for coal and charcoal, and hence comes French charbon, meaning charcoal. In German, Dutch and Danish, the names for carbon are Kohlenstoff, koolstof and kulstof respectively, all literally meaning coal-substance.
Carbon was discovered in prehistory and was known in the forms of soot and charcoal to the earliest human civilizations. Diamonds were known probably as early as 2500 BCE in China, while carbon in the forms of charcoal was made around Roman times by the same chemistry as it is today, by heating wood in a pyramid covered with clay to exclude air.
In 1722, René A. F. de Réaumur demonstrated that iron was transformed into steel through the absorption of some substance, now known to be carbon. In 1772, Antoine Lavoisier showed that diamonds are a form of carbon, when he burned samples of carbon and diamond then showed that neither produced any water and that both released the same amount of carbon dioxide per gram.
Carl Wilhelm Scheele showed that graphite, which had been thought of as a form of lead, was instead a type of carbon. In 1786, the French scientists Claude Louis Berthollet, Gaspard Monge and C. A. Vandermonde then showed that this substance was carbon. In their publication they proposed the name carbone (Latin carbonum) for this element. Antoine Lavoisier listed carbon as an element in his 1789 textbook.
A new allotrope of carbon, fullerene, that was discovered in 1985 includes nanostructured forms such as buckyballs and nanotubes. Their discoverers received the Noble Prize in Chemistry in 1996. The resulting renewed interest in new forms, lead to the discovery of further exotic allotropes, including glassy carbon, and the realization that "amorphous carbon" is not strictly amorphous.
## Applications
Carbon is essential to all known living systems, and without it life as we know it could not exist (see alternative biochemistry). The major economic use of carbon other than food and wood is in the form of hydrocarbons, most notably the fossil fuel] methane gas and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce, amongst others, gasoline and kerosene, through a distillation process, in refineries. Cellulose is natural carbon-containing polymer produced by plants in the form of cellulose, cotton, linen, hemp. Commercially valuable carbon polymers of animal origin include wool, cashmere and silk. Plastics are made from synthetic carbon polymers, often with oxygen and nitrogen atoms included at regular intervals in the main polymer chain. The raw materials for many of these synthetic substances come from crude oil.
The uses of carbon and its compounds are extremely varied. It can form alloys with iron, of which the most common is carbon steel. Graphite is combined with clays to form the 'lead' used in pencils used for writing and drawing. It is also used as a lubricant and a pigment, as a moulding material in glass manufacture, in electrodes for dry batteries and in electroplating and electroforming, in brushes for electric motors and as a neutron moderator in nuclear reactors.
Charcoal is used as a drawing material in artwork, for grilling, and in many other uses including iron smelting. Wood, coal and oil are used as fuel for production of energy and space heating. Gem quality diamond is used in jewelry, and Industrial diamonds are used in drilling, cutting and polishing tools for machining metals and stone. Plastics are made from fossil hydrocarbons, and carbon fiber, made by pyrolysis of synthetic polyester fibers is used to reinforce plastics to form advanced, lightweight composite materials. Carbon fiber is made by pyrolysis of extruded and stretched filaments of polyacrylonitrile (PAN) and other organic substances. The crystallographic structure and mechanical properties of the fiber depend on the type of starting material, and on the subsequent processing. Carbon fibers made from PAN have structure resembling narrow filaments of graphite, but thermal processing may re-order the structure into a continuous rolled sheet. The result is fibers with higher specific tensile strength than steel.
Carbon black is used as the black pigment in printing ink, artist's oil paint and water colours, carbon paper, automotive finishes, India ink and laser printer toner. Carbon black is also used as a filler in rubber products such as tyres and in plastic compounds. Activated charcoal is used as an absorbent and adsorbent in filter material in applications as diverse as gas masks, water purification and kitchen extractor hoods and in medicine to absorb toxins, poisons, or gases from the digestive system. Carbon is used in chemical reduction at high temperatures. Coke is used to reduce iron ore into iron. Case hardening of steel is achieved by heating finished steel components in carbon powder. Carbides of silicon, tungsten, boron and titanium, are among the hardest known materials, and are used as abrasives in cutting and grinding tools. Carbon compounds make up most of the materials used in clothing, such as natural and synthetic textiles and leather, and almost all of the interior surfaces in the built environment other than glass, stone and metal.
# Production
## Graphite Production
Commercially viable natural deposits of graphite occur in many parts of the world, but the most important sources economically are in China, India, Brazil, and North Korea. Graphite deposits are of metamorphic origin, found in association with quartz, mica and feldspars in schists, gneisses and metamorphosed sandstones and limestone as lenses or veins, sometimes of a metre or more in thickness. Deposits of graphite in Borrowdale, Cumberland, England were at first of sufficient size and purity that, until the 1800s, pencils were made simply by sawing blocks of natural graphite into strips before encasing the strips in wood. Today, smaller deposits of graphite are obtained by crushing the parent rock and floating the lighter graphite out on water.
# Precautions
Pure carbon has extremely low toxicity and can be handled and even ingested safely in the form of graphite or charcoal. It is resistant to dissolution or chemical attack, even in the acidic contents of the digestive tract, for example. Consequently if it gets into body tissues it is likely to remain there indefinitely. Carbon black was probably one of the first pigments to be used for tattooing, and Ötzi the Iceman was found to have carbon tattoos that survived during his life and for 5200 years after his death. However, inhalation of coal dust or soot (carbon black) in large quantities can be dangerous, irritating lung tissues and causing the congestive lung disease coalworker's pneumoconiosis. Similarly, diamond dust used as an abrasive can do harm if ingested or inhaled. Microparticles of carbon are produced in diesel engine exhaust fumes, and may accumulate in the lungs. In these examples, the harmful effects may result from contamination of the carbon particles, with organic chemicals or heavy metals for example, rather than from the carbon itself.
Carbon may also burn vigorously and brightly in the presence of air at high temperatures, as in the Windscale fire, which was caused by sudden release of stored Wigner energy in the graphite core. Large accumulations of coal, which have remained inert for hundred of millions of years in the absence of oxygen, may spontaneously combust when exposed to air, for example in coal mine waste tips.
The great variety of carbon compounds include such lethal poisons as tetrodotoxin, the lectin ricin from seeds of the castor oil plant Ricinus communis, cyanide (CN-) and carbon monoxide; and such essentials to life as glucose and protein. | Carbon
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Template:Infobox carbon
Carbon (Template:PronEng) is a chemical element with the symbol C and atomic number 6. It is a group 14, nonmetallic, tetravalent element, that presents several allotropic forms of which the best known are graphite (the thermodynamically stable form under normal conditions), diamond, and amorphous carbon.[1] There are three naturally occurring isotopes: 12C and 13C are stable, and 14C is radioactive, decaying with a half-life of about 5700 years.[2] Carbon is one of the few elements known to man since antiquity.[3][4] The name "carbon" comes from Latin language carbo, coal, and in some Romance languages, the word carbon can refer both to the element and to coal.
It is the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body it is the second most abundant element by mass (about 18.5%) after oxygen.[5] This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.
The physical properties of carbon vary widely with the allotropic form. For example, diamond is highly transparent, while graphite is opaque and black. Diamond is among the hardest materials known, while graphite is soft enough to form a streak on paper. Diamond has a very low electric conductivity, while graphite is a very good conductor. Also, diamond has the highest thermal conductivity of all known materials under normal conditions. All the allotropic forms are solids under normal conditions.
All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil and methane clathrates. Carbon forms more compounds than any other element, with almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such compounds that are theoretically possible under standard conditions.[6]
# Characteristics
Carbon exhibits remarkable properties, some paradoxical. Its different forms or allotropes (see below) include the hardest naturally occurring substance (diamond) and also one of the softest substances (graphite) known. Moreover, it has a great affinity for bonding with other small atoms, including other carbon atoms, and is capable of forming multiple stable covalent bonds with such atoms. Because of these properties, carbon is known to form nearly ten million different compounds, the large majority of all chemical compounds.[6] Moreover, carbon has the highest melting/sublimation point of all elements. At atmospheric pressure it has no actual melting point as its triple point is at 10 MPa (100 bar) so it sublimates above 4000 K. Carbon sublimes in a carbon arc which has a temperature of about 5800K. Thus irrespective of its allotropic form, carbon remains solid at higher temperatures than the highest melting point metals such as tungsten or rhenium. Although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature.
Carbon compounds form the basis of all life on Earth and the carbon-nitrogen cycle provides some of the energy produced by the Sun and other stars. Although it forms an extraordinary variety of compounds, most forms of carbon are comparatively unreactive under normal conditions. At standard temperature and pressure, it resists all but the strongest oxidizers. It does not react with sulfuric acid, hydrochloric acid, chlorine or any alkalis. At elevated temperatures carbon reacts with oxygen to form carbon oxides, and will reduce such metal oxides as iron oxide to the metal. This exothermic reaction is used in the iron and steel industry to control the carbon content of steel:
Fe3O4 + 4C(s) → 3Fe(s) + 4CO(g)
with sulfur to form carbon disulfide and with steam in the coal-gas reaction
C(s) + H2O(g) → CO(g) + H2(g).
Carbon combines with some metals at high temperatures to form metallic carbides, such as the iron carbide cementite in steel, and tungsten carbide, widely used as an abrasive and for making hard tips for cutting tools.
The system of carbon allotropes spans a range of extremes:
## Allotropes
Atomic carbon is a very short-lived specie and therefore, carbon is stabilized in various multi-atomic structures with different molecular configurations called allotropes. The three relatively well-known allotropes of carbon are amorphous carbon, graphite, and diamond. Once considered exotic, fullerenes are nowadays commonly synthesized and used in research; they include buckyballs,[7][8] carbon nanotubes,[9] carbon nanobuds[10] and nanofibers,[11].[12] Several other exotic allotropes have also been discovered, such as aggregated diamond nanorods,[13] lonsdaleite,[14] glassy carbon,[15] carbon nanofoam[16] and linear acetylenic carbon.[17]
- The amorphous form, is an assortment of carbon atoms in a non-crystalline, irregular, glassy state, which is essentially graphite but not held in a crystalline macrostructure. It is present as a powder, and is the main constituent of substances such as charcoal, lampblack (soot) and activated carbon.
- At normal pressures carbon takes the form of graphite, in which each atom is bonded trigonally to three others in a plane composed of fused hexagonal rings, just like those in aromatic hydrocarbons. The resulting network is 2-dimensional, and the resulting flat sheets are stacked and loosely bonded through weak Van der Waals forces. This gives graphite its softness and its cleaving properties (the sheets slip easily past one another). Because of the delocalization of one of the outer electrons of each atom to form a π-cloud, graphite conducts electricity, but only in the plane of each covalently bonded sheet. This results in a lower bulk electrical conductivity for carbon than for most metals. The delocalization also accounts for the energetic stability of graphite over diamond at room temperature.
- At very high pressures carbon forms the more compact allotrope diamond, having nearly twice the density of graphite. Here, each atom is bonded tetrahedrally to four others, thus making a 3-dimensional network of puckered six-membered rings of atoms. Diamond has the same cubic structure as silicon and germanium and, thanks to the strength of the carbon-carbon bonds is the hardest naturally occurring substance in terms of resistance to scratching. Contrary to the popular belief that "diamonds are forever", they are in fact thermodynamically unstable under normal conditions and transform into graphite.[1] But due to a high activation energy barrier, the transition into graphite is so extremely slow at room temperature as to be unnoticeable. Under some conditions, carbon crystallizes as Lonsdaleite, a form similar to diamond but forming a hexagonal crystal lattice.[14]
- Fullerenes have a graphite-like structure, but instead of purely hexagonal packing, they also contain pentagons (or even heptagons) of carbon atoms, which bend the sheet into spheres, ellipses or cylinders. The properties of fullerenes (split into buckyballs, buckytubes and nanobuds) have not yet been fully analyzed and represents an intense are of research in nanomaterials. The name "fullerene" is given after Richard Buckminster Fuller, developer of some geodesic domes, which resemble the structure of fullerenes. The buckyballs are fairly large molecules formed completely of carbon bonded trigonally, forming spheroids (the best-known and simplest is the soccerball-shaped structure C60 buckminsterfullerene).[7] Carbon nanotubes are structurally similar to buckyballs, except that each atom is bonded trigonally in a curved sheet that forms a hollow cylinder.[8][9] Nanobuds were first published in 2007 and are hybrid bucky tube/buckyball materials (buckyballs are covalently bonded to the outer wall of a nanotube) that combine the properties of both in a single structure.[10]
- Of the other discovered allotropes, aggregated diamond nanorods have been synthesised in 2005 and are believed to be the hardest substance known yet.[18] Carbon nanofoam is a ferromagnetic allotrope discovered in 1997. It consists of a low-density cluster-assembly of carbon atoms strung together in a loose three-dimensional web, in which the atoms are bonded trigonally in six- and seven-membered rings. It is among the lightest known solids, with a density of about 2 kg/m³.[19] Similarly, glassy carbon contains a high proportion of closed porosity.[15] But unlike normal graphite, the graphitic layers are not stacked like pages in a book, but have a more random arrangement. Linear acetylenic carbon[17] has the chemical structure[20] -(C:::C)n- .Carbon in this modification is linear with sp orbital hybridisation, and is a polymer with alternating single and triple bonds. This type of carbyne is of considerable interest to nanotechnology as its Young's modulus is forty times that of the hardest known material - diamond.[21]
## Occurrence
Carbon is the fourth most abundant chemical element in the universe by mass after hydrogen, helium, and oxygen. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. Some meteorites contain microscopic diamonds that were formed when the solar system was still a protoplanetary disk. Microscopic diamonds may also be formed by the intense pressure and high temperature at the sites of meteorite impacts.[22]
In combination with oxygen in carbon dioxide, carbon is found in the Earth's atmosphere (in quantities of approximately 810 gigatonnes) and dissolved in all water bodies (approximately 36000 gigatonnes). Around 1900 gigatonnes are present in the biosphere. Hydrocarbons (such as coal, petroleum, and natural gas) contain carbon as well — coal "reserves" (not "resources") amount to around 900 gigatonnes, and oil reserves around 150 gigatonnes. With smaller amounts of calcium, magnesium, and iron, carbon is a major component of very large masses carbonate rock (limestone, dolomite, marble etc.).
Coal is a significant commercial source of mineral carbon; anthracite containing 92-98% carbon and the largest source (4000 Gt, or 80% of coal, gas and oil reserves) of carbon in a form suitable for use as fuel.[23]
Graphite is found in large quantities in New York and Texas in the United States, Russia, Mexico, Greenland, and India.
Natural diamonds occur in the mineral kimberlite, found in ancient volcanic "necks," or "pipes". Most diamond deposits are in Africa, notably in South Africa, Namibia, Botswana, the Republic of the Congo, and Sierra Leone. There are also deposits in Arkansas, Canada, the Russian Arctic, Brazil and in Northern and Western Australia.
Carbon is also found in abundance in the Sun, stars, comets, and atmospheres of most planets. Diamonds are now also being recovered from the ocean floor off the Cape of Good Hope. About 30% of all industrial diamonds used in the U.S. are now made synthetically.
According to studies from the Massachusetts Institute of Technology, an estimate of the global carbon budget is:
Carbon-14 is formed in upper layers of the troposphere and the stratosphere, at altitudes of 9–15 km, by a reaction that is precipitated by cosmic rays. Thermal neutrons are produced that collide with the nuclei of nitrogen-14, forming carbon-14 and a proton.
## Isotopes
Isotopes of carbon are atomic nuclei that contain six protons plus a number of neutrons (varying from 2 to 16). Carbon has two stable, naturally occurring isotopes.[2] The isotope carbon-12 (12C) forms 98.93% of the carbon on Earth, while carbon-13 (13C) forms the remaining 1.07%.[2] The concentration of 12C is further increased in biological materials because biochemical reactions discriminate against 13C.[24] In 1961 the International Union of Pure and Applied Chemistry (IUPAC) adopted the isotope carbon-12 as the basis for atomic weights.[25] Identification of carbon in NMR experiments is done with the isotope 13C.
Carbon-14 (14C) is a naturally occurring radioisotope which occurs in trace amounts on Earth of up to 1 part per trillion (0.0000000001%), mostly confined to the atmosphere and superficial deposits, particularly of peat and other organic materials.[26] This isotope decays by 0.158 MeV β- emission. Because of its relatively short half-life of 5730 years, 14C is virtually absent in ancient rocks, but is created in the upper atmosphere (lower stratosphere and upper troposphere) by interaction of nitrogen with cosmic rays.[27] The abundance of 14C in the atmosphere and in living organisms is almost constant, but decreases predictably in their bodies after death. This principle is used in radiocarbon dating, discovered in 1949, which has been used extensively to determine the age of carbonaceous materials with ages up to about 40,000 years.[28][29]
There are 15 known isotopes of carbon and the shortest-lived of these is 8C which decays through proton emission and alpha decay and has a half-life of 1.98739x10-21 s.[30] The exotic 19C exhibits a nuclear halo, which means its radius is appreciably larger than would be expected if the nucleus was a sphere of constant density.[31]
## Formation in stars
Formation of the carbon atomic nucleus requires a nearly simultaneous triple collision of alpha particles (helium nuclei) within the core of a giant or supergiant star. This happens in conditions of temperature and helium concentration that the rapid expansion and cooling of the early universe prohibited, and therefore no significant carbon was created during the Big Bang. Instead, the interiors of stars in the horizontal branch transform three helium nuclei into carbon by means of this triple-alpha process. In order to be available for formation of life as we know it, this carbon must then later be scattered into space as dust, in supernova explosions, as part of the material which later forms second- and third-generation star systems which have planets accreted from such dust. The Solar System is one such third-generation star system.
One of the fusion mechanisms powering stars is the carbon-nitrogen cycle.
Rotational transitions of various isotopic forms of carbon monoxide (e.g. 12CO, 13CO, and C18O) are detectable in the submillimeter regime, and are used in the study of newly forming stars in molecular clouds.
## Carbon cycle
Under terrestrial conditions, conversion of one element to another is very rare. Therefore, the amount of carbon on Earth is effectively constant. Thus, processes that use carbon must obtain it somewhere and dispose of it somewhere else. The paths that carbon follows in the environment make up the carbon cycle. For example, plants draw carbon dioxide out of their environment and use it to build biomass, as in carbon respiration or the Calvin cycle, a process of carbon fixation. Some of this biomass is eaten by animals, whereas some carbon is exhaled by animals as carbon dioxide. The carbon cycle is considerably more complicated than this short loop; for example, some carbon dioxide is dissolved in the oceans; dead plant or animal matter may become petroleum or coal, which can burn with the release of carbon, should bacteria not consume it.
# Compounds
## Inorganic compounds
Commonly carbon-containing compounds which are associated with minerals or which do not contain hydrogen or fluorine, are treated separately from classical organic compounds; however the definition is not rigid (see reference articles above). Among these are the simple oxides of carbon. The most prominent oxide is carbon dioxide (CO2). This was once the principal constituent of the paleoatmosphere, but is a minor component of the Earth's atmosphere today.[32] Dissolved in water, it forms carbonic acid (H2CO3), but as most compounds with multiple single-bonded oxygens on a single carbon it is unstable. Through this intermediate, though, resonance-stabilized carbonate ions are produced. Some important minerals are carbonates, notably calcite. Carbon disulfide (CS2) is similar.
The other common oxide is carbon monoxide (CO). It is formed by incomplete combustion, and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly polar, resulting in a tendency to bind permanently to hemoglobin molecules, displacing oxygen, which has a lower binding affinity.[33][34] Cyanide (CN–), has a similar structure, but behaves much like a halide ion (pseudohalogen). For example it can form the nitride cyanogen molecule ((CN)2), similar to diatomic halides. Other uncommon oxides are carbon suboxide (C3O2),[35] the unstable dicarbon monoxide (C2O),[36][37] and even carbon trioxide (CO3).[38][39]
With reactive metals, such as tungsten, carbon forms either carbides (C4–), or acetylides (C22–) to form alloys with high melting points. These anions are also associated with methane and acetylene, both very weak acids. With an electronegativity of 2.5,[40] carbon prefers to form covalent bonds. A few carbides are covalent lattices, like carborundum (SiC), which resembles diamond.
## Organic compounds
Carbon has the ability to form very long chains with interconnecting C-C bonds. This property is called catenation. Carbon-carbon bonds are strong, and stable. This property allows carbon to form an almost infinite number of compounds; in fact, there are more known carbon-containing compounds than all the compounds of the other chemical elements combined except those of hydrogen (because almost all organic compounds contain hydrogen too).
The simplest form of an organic molecule is the hydrocarbon—a large family of organic molecules that are composed of hydrogen atoms bonded to a chain of carbon atoms. Chain length, side chains and functional groups all affect the properties of organic molecules. By IUPAC's definition, all the other organic compounds are functionalized compounds of hydrocarbons.
Carbon occurs in all organic life and is the basis of organic chemistry. When united with hydrogen, it forms various flammable compounds called hydrocarbons which are important to industry as chemical feedstock for the manufacture of plastics, petrochemicals and as fossil fuels.
When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds including sugars, celluloses, lignans, chitins, alcohols, fats, and aromatic esters, carotenoids and terpenes. With nitrogen it forms alkaloids, and with the addition of sulfur also it forms antibiotics, amino acids and proteins. With the addition of phosphorus to these other elements, it forms DNA and RNA, the chemical codes of life, and adenosine triphosphate (ATP), the most important energy-transfer molecules in all living cells.
# History and etymology
The English name carbon comes from the Latin carbo for coal and charcoal,[41] and hence comes French charbon, meaning charcoal. In German, Dutch and Danish, the names for carbon are Kohlenstoff, koolstof and kulstof respectively, all literally meaning coal-substance.
Carbon was discovered in prehistory and was known in the forms of soot and charcoal to the earliest human civilizations. Diamonds were known probably as early as 2500 BCE in China, while carbon in the forms of charcoal was made around Roman times by the same chemistry as it is today, by heating wood in a pyramid covered with clay to exclude air.[42][43]
In 1722, René A. F. de Réaumur demonstrated that iron was transformed into steel through the absorption of some substance, now known to be carbon.[44] In 1772, Antoine Lavoisier showed that diamonds are a form of carbon, when he burned samples of carbon and diamond then showed that neither produced any water and that both released the same amount of carbon dioxide per gram.
Carl Wilhelm Scheele showed that graphite, which had been thought of as a form of lead, was instead a type of carbon.[45] In 1786, the French scientists Claude Louis Berthollet, Gaspard Monge and C. A. Vandermonde then showed that this substance was carbon.[46] In their publication they proposed the name carbone (Latin carbonum) for this element. Antoine Lavoisier listed carbon as an element in his 1789 textbook.[47]
A new allotrope of carbon, fullerene, that was discovered in 1985[48] includes nanostructured forms such as buckyballs and nanotubes.[7] Their discoverers received the Noble Prize in Chemistry in 1996.[49] The resulting renewed interest in new forms, lead to the discovery of further exotic allotropes, including glassy carbon, and the realization that "amorphous carbon" is not strictly amorphous.[15]
## Applications
Carbon is essential to all known living systems, and without it life as we know it could not exist (see alternative biochemistry). The major economic use of carbon other than food and wood is in the form of hydrocarbons, most notably the fossil fuel] methane gas and crude oil (petroleum). Crude oil is used by the petrochemical industry to produce, amongst others, gasoline and kerosene, through a distillation process, in refineries. Cellulose is natural carbon-containing polymer produced by plants in the form of cellulose, cotton, linen, hemp. Commercially valuable carbon polymers of animal origin include wool, cashmere and silk. Plastics are made from synthetic carbon polymers, often with oxygen and nitrogen atoms included at regular intervals in the main polymer chain. The raw materials for many of these synthetic substances come from crude oil.
The uses of carbon and its compounds are extremely varied. It can form alloys with iron, of which the most common is carbon steel. Graphite is combined with clays to form the 'lead' used in pencils used for writing and drawing. It is also used as a lubricant and a pigment, as a moulding material in glass manufacture, in electrodes for dry batteries and in electroplating and electroforming, in brushes for electric motors and as a neutron moderator in nuclear reactors.
Charcoal is used as a drawing material in artwork, for grilling, and in many other uses including iron smelting. Wood, coal and oil are used as fuel for production of energy and space heating. Gem quality diamond is used in jewelry, and Industrial diamonds are used in drilling, cutting and polishing tools for machining metals and stone. Plastics are made from fossil hydrocarbons, and carbon fiber, made by pyrolysis of synthetic polyester fibers is used to reinforce plastics to form advanced, lightweight composite materials. Carbon fiber is made by pyrolysis of extruded and stretched filaments of polyacrylonitrile (PAN) and other organic substances. The crystallographic structure and mechanical properties of the fiber depend on the type of starting material, and on the subsequent processing. Carbon fibers made from PAN have structure resembling narrow filaments of graphite, but thermal processing may re-order the structure into a continuous rolled sheet. The result is fibers with higher specific tensile strength than steel.
Carbon black is used as the black pigment in printing ink, artist's oil paint and water colours, carbon paper, automotive finishes, India ink and laser printer toner. Carbon black is also used as a filler in rubber products such as tyres and in plastic compounds. Activated charcoal is used as an absorbent and adsorbent in filter material in applications as diverse as gas masks, water purification and kitchen extractor hoods and in medicine to absorb toxins, poisons, or gases from the digestive system. Carbon is used in chemical reduction at high temperatures. Coke is used to reduce iron ore into iron. Case hardening of steel is achieved by heating finished steel components in carbon powder. Carbides of silicon, tungsten, boron and titanium, are among the hardest known materials, and are used as abrasives in cutting and grinding tools. Carbon compounds make up most of the materials used in clothing, such as natural and synthetic textiles and leather, and almost all of the interior surfaces in the built environment other than glass, stone and metal.
# Production
## Graphite Production
Commercially viable natural deposits of graphite occur in many parts of the world, but the most important sources economically are in China, India, Brazil, and North Korea.[50] Graphite deposits are of metamorphic origin, found in association with quartz, mica and feldspars in schists, gneisses and metamorphosed sandstones and limestone as lenses or veins, sometimes of a metre or more in thickness. Deposits of graphite in Borrowdale, Cumberland, England were at first of sufficient size and purity that, until the 1800s, pencils were made simply by sawing blocks of natural graphite into strips before encasing the strips in wood. Today, smaller deposits of graphite are obtained by crushing the parent rock and floating the lighter graphite out on water.
# Precautions
Pure carbon has extremely low toxicity and can be handled and even ingested safely in the form of graphite or charcoal. It is resistant to dissolution or chemical attack, even in the acidic contents of the digestive tract, for example. Consequently if it gets into body tissues it is likely to remain there indefinitely. Carbon black was probably one of the first pigments to be used for tattooing, and Ötzi the Iceman was found to have carbon tattoos that survived during his life and for 5200 years after his death.[51] However, inhalation of coal dust or soot (carbon black) in large quantities can be dangerous, irritating lung tissues and causing the congestive lung disease coalworker's pneumoconiosis. Similarly, diamond dust used as an abrasive can do harm if ingested or inhaled. Microparticles of carbon are produced in diesel engine exhaust fumes, and may accumulate in the lungs.[52] In these examples, the harmful effects may result from contamination of the carbon particles, with organic chemicals or heavy metals for example, rather than from the carbon itself.
Carbon may also burn vigorously and brightly in the presence of air at high temperatures, as in the Windscale fire, which was caused by sudden release of stored Wigner energy in the graphite core. Large accumulations of coal, which have remained inert for hundred of millions of years in the absence of oxygen, may spontaneously combust when exposed to air, for example in coal mine waste tips.
The great variety of carbon compounds include such lethal poisons as tetrodotoxin, the lectin ricin from seeds of the castor oil plant Ricinus communis, cyanide (CN-) and carbon monoxide; and such essentials to life as glucose and protein. | https://www.wikidoc.org/index.php/Carbon | |
2d489dec40a5b961473df8cfe3a3ad1902fc8b51 | wikidoc | Septum | Septum
# Overview
A septum (Latin: something that encloses; plural Septa) is a partition separating two cavities or spaces. Septum or septa may refer to:
- Septum, a partition of two cavities or spaces
- Septum (marine biology), in marine biology, a thin membrane separating each shell chamber in cephalopods that retained their external shell (Cephalopod Septa]]: walls between each chamber, or siphuncle, in shells of nautiloids, ammonites, and belemnites; i.e. cephalopods that retain an external shell.)
- The wall dividing the right side of the heart from the left side.
- Septum nasi or septum, the cartilage wall separating the nostrils (Nasal septum: the cartilage wall separating the nostrils of the human nose. Often deviated or perforated through physical injury or cocaine abuse.)
- Septum pellucidum or septum lucidum, a thin structure separating two fluid pockets in the brain
- Interatrial septum, the wall of tissue that separates the left and right atria of the heart
- Interventricular septum or median septum, the wall separating the left and right ventricles of the heart
- Lingual septum, a vertical layer of fibrous tissue that separates the halves of the tongue
- Orbital septum, a palpabral ligament in the upper and lower eyelids
- Uterine septum or uterus didelphys, a malformation of the uterus
- Septum, in mycology, the wall partitioning fungal hyphae into discrete cells
- Septation, microbiology, the process whereby a cell divides into two cells
- Fungi produce septa to partition filamentous hyphae into discrete cells.
# Histology
Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen a soft cellular tissue, and they also provide planes of ingress for small blood vessels. Because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instances, a septum is a cross-wall.
The septum is also found within the chambers of the heart. It provides strength to the walls of the heart and separates the left and right sides of the heart.
# Chemistry
In chemistry and other experimental sciences, septa are rubber stoppers which seal flasks or bottles. They are designed to be pierced by a needle or cannula which allows fluids to be transferred. Septa are often used together with Schlenk flasks and Schlenk lines to handle oxygen- or moisture-sensitive materials.
# Particle accelerators
Septum magneta and electrostatic septum are two types of septa that can deflect an ejected beam while not affecting the orbiting beam. These devices are used with a circular particle beam accelerator to inject or eject a beam of particles to or from an accelerator.
# Brain physiology
Part of the limbic system that regulates emotions and the ability to learn and control impulses as well as such drives as sex, hunger, thirst, aggression, and fear. The septum (or septal nuclei) in the brain is named for its approximate shape (partition). The septum is rich with nicotonic cholinergic receptors.
de:Septum
simple:Septum
sv:Septum | Septum
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
A septum (Latin: something that encloses; plural Septa) is a partition separating two cavities or spaces. Septum or septa may refer to:
- Septum, a partition of two cavities or spaces
- Septum (marine biology), in marine biology, a thin membrane separating each shell chamber in cephalopods that retained their external shell (Cephalopod Septa]]: walls between each chamber, or siphuncle, in shells of nautiloids, ammonites, and belemnites; i.e. cephalopods that retain an external shell.)
- The wall dividing the right side of the heart from the left side.
- Septum nasi or septum, the cartilage wall separating the nostrils (Nasal septum: the cartilage wall separating the nostrils of the human nose. Often deviated or perforated through physical injury or cocaine abuse.)
- Septum pellucidum or septum lucidum, a thin structure separating two fluid pockets in the brain
- Interatrial septum, the wall of tissue that separates the left and right atria of the heart
- Interventricular septum or median septum, the wall separating the left and right ventricles of the heart
- Lingual septum, a vertical layer of fibrous tissue that separates the halves of the tongue
- Orbital septum, a palpabral ligament in the upper and lower eyelids
- Uterine septum or uterus didelphys, a malformation of the uterus
- Septum, in mycology, the wall partitioning fungal hyphae into discrete cells
- Septation, microbiology, the process whereby a cell divides into two cells
- Fungi produce septa to partition filamentous hyphae into discrete cells.
# Histology
Histological septa are seen throughout most tissues of the body, particularly where they are needed to stiffen a soft cellular tissue, and they also provide planes of ingress for small blood vessels. Because the dense collagen fibres of a septum usually extend out into the softer adjacent tissues, microscopic fibrous septa are less clearly defined than the macroscopic types of septa listed above. In rare instances, a septum is a cross-wall.
The septum is also found within the chambers of the heart. It provides strength to the walls of the heart and separates the left and right sides of the heart.
# Chemistry
In chemistry and other experimental sciences, septa are rubber stoppers which seal flasks or bottles. They are designed to be pierced by a needle or cannula which allows fluids to be transferred. Septa are often used together with Schlenk flasks and Schlenk lines to handle oxygen- or moisture-sensitive materials.
# Particle accelerators
Septum magneta and electrostatic septum are two types of septa that can deflect an ejected beam while not affecting the orbiting beam. These devices are used with a circular particle beam accelerator to inject or eject a beam of particles to or from an accelerator.
# Brain physiology
Part of the limbic system that regulates emotions and the ability to learn and control impulses as well as such drives as sex, hunger, thirst, aggression, and fear. The septum (or septal nuclei) in the brain is named for its approximate shape (partition). The septum is rich with nicotonic cholinergic receptors.
de:Septum
simple:Septum
sv:Septum
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Cardiac_septa | |
c992889d20e3131415a0e4cdcac7a831d06b0786 | wikidoc | Carpus | Carpus
In tetrapods, the carpus is the cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers (or toes in quadrupeds), whereas those of the metacarpus do. (The corresponding part of the foot is the tarsus.) Carpal bones are not considered part of the hand but are part of the wrist. The carpal bones allow the wrist to move and rotate vertically and horizontally.
# Variations
In some macropods, the scaphoid and lunar bones are fused into the scapholunar bone.
# The carpus
## Mnemonics
There exist several mnemonics to remember these bones:
- Some Lovers Try Positions That They Can't Handle.
- Sally left the party / to take Cathy home.
# Common characteristics of the carpal bones
Each bone (excepting the pisiform) presents six (6) surfaces.
Of these the palmar or anterior and the dorsal or posterior surfaces are rough, for ligamentous attachment; the dorsal surfaces being the broader, except in the lunate.
The superior or proximal, and inferior or distal surfaces are articular, the superior generally convex, the inferior concave; the medial and lateral surfaces are also articular where they are in contact with contiguous bones, otherwise they are rough and tuberculated.
The structure in all is similar: cancellous tissue enclosed in a layer of compact bone. | Carpus
Template:Infobox Bone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
In tetrapods, the carpus is the cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers (or toes in quadrupeds), whereas those of the metacarpus do. (The corresponding part of the foot is the tarsus.) Carpal bones are not considered part of the hand but are part of the wrist. The carpal bones allow the wrist to move and rotate vertically and horizontally.
# Variations
In some macropods, the scaphoid and lunar bones are fused into the scapholunar bone.[1]
# The carpus
## Mnemonics
There exist several mnemonics to remember these bones:[2]
- Some Lovers Try Positions That They Can't Handle.
- Sally left the party / to take Cathy home.
# Common characteristics of the carpal bones
Each bone (excepting the pisiform) presents six (6) surfaces.
Of these the palmar or anterior and the dorsal or posterior surfaces are rough, for ligamentous attachment; the dorsal surfaces being the broader, except in the lunate.
The superior or proximal, and inferior or distal surfaces are articular, the superior generally convex, the inferior concave; the medial and lateral surfaces are also articular where they are in contact with contiguous bones, otherwise they are rough and tuberculated.
The structure in all is similar: cancellous tissue enclosed in a layer of compact bone. | https://www.wikidoc.org/index.php/Carpal | |
9ee7deb1f7dc04744853b193065dae4cb689ecc3 | wikidoc | Cashew | Cashew
The cashew (Anacardium occidentale; syn. Anacardium curatellifolium A.St.-Hil.) is a tree in the flowering plant family Anacardiaceae. The plant is native to northeastern Brazil, where it is called by its Portuguese name Caju (the fruit) or Cajueiro (the tree). It is now widely grown in tropical climates for its cashew "nuts" (see below) and cashew apples.
It is a small evergreen tree growing to 10-12 m tall, with a short, often irregularly-shaped trunk. The leaves are spirally arranged, leathery textured, elliptic to obovate, 4 to 22 cm long and 2 to 15 cm broad, with a smooth margin. The flowers are produced in a panicle or corymb up to 26 cm long, each flower small, pale green at first then turning reddish, with five slender, acute petals 7 to 15 mm long.
What appears to be the fruit of the cashew tree is an oval or pear-shaped accessory fruit or false fruit that develops from the receptacle of the cashew flower. Called the cashew apple, better known in Central America as "marañón", it ripens into a yellow and/or red structure about 5–11 cm long.
The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the pseudofruit. Actually, the drupe develops first on the tree, and then the peduncle expands into the pseudofruit. Within the true fruit is a single seed, the cashew nut. Although a nut in the culinary sense, in the botanical sense the fruit of the cashew is a seed. The seed is surrounded by a double shell containing a caustic phenolic resin, urushiol, a potent skin irritant toxin also found in the related poison ivy. Some people are allergic to cashews, but cashews are a less frequent allergen than some nuts.
Other vernacular names include cajueiro, cashu, casho, acajuiba, caju, acajou, acaju, acajaiba, alcayoiba, anacarde, anacardier, anacardo, cacajuil, cajou, gajus, godambi (in Kannada), jeedi pappu (in Telugu), jocote maranon, maranon, merey, noix d’acajou, pomme cajou, pomme, jambu, jambu golok, jambu mete, jambu monyet, jambu terong, kasoy. In the Antilles, specifically Puerto Rico, it is known as pajuil and the pseudofruit is the main used part as raw fruit.
# Cashew Industry
Originally spread from Brazil by the Portuguese, the cashew tree is now cultivated in all regions with a sufficiently warm and humid climate.
Cashew is produced in around 32 countries of the world. The world production figures of cashew crop, published by FAO, was around 2.7 million tons per annum. The major raw cashew producing countries with their production figures in 2005 (as per the UN's Food and Agriculture Organization) are Vietnam (960,800 tons), Nigeria (594,000), India (460,000 tons), Brazil (147,629 tons) and Indonesia (122,000 tons).
World’s total area under the cultivation of cashew is around 35,100 km². India ranks first in area utilized for cashew production, though its yields are relatively low. The world’s average yield is 700 pounds per acre (780 kg/hectare) of land
Collectively, Vietnam, India and Brazil account for more than 90% of all cashew kernel exports. Some varieties of cashews come from Kollam or Quilon in Kerala, Southern India which alone produces 4,000 tons of cashews per annum. The major trading centers of cashew in India are Palasa, Kollam or Quilon Mangalore and Kochi.
# Uses
The cashew apple is used for its juicy but acidic pulp, which can be eaten raw or used in the production of jam, chutney, or various beverages. Depending on local customs, its juice is also processed and distilled into liquor or consumed diluted and sugared as a refreshing drink, Cajuína. Ripe cashew apples also make good caipirinha. In Goa, India, the cashew apple is the source of juicy pulp used to prepare fenny, a locally popular distilled liquor. In Nicaragua the cashew apple has many uses, it is often eaten or made into juice and also processed to create sweets and jellies. Other uses in Nicaragua include fermentation to produce wine and home-vinegar. The cashew apple contains much tannin and is very perishable. For this reason, in many parts of the world, the false fruit is simply discarded after removal of the cashew nut.
The urushiol must be removed from the dark green nut shells before the seed inside is processed for consumption; this is done by shelling the nuts, a somewhat hazardous process, and exceedingly painful skin rashes (similar to poison-ivy rashes) among processing workers are common. In India urushiol is traditionally used to control tamed elephants by their mahouts (riders or keepers). The so-called "raw cashews" available in health food shops have been cooked but not roasted or browned.
Cashew nuts are a common ingredient in Asian cooking. They can also be ground into a spread called cashew butter similar to peanut butter. Cashews have a very high oil content, and they are used in some other nut butters to add extra oil. Cashews contain 180 calories per ounce (6 calories per gram), 70% of which are from fat.
The liquid contained within the shell casing of the cashew, known as Cashew Nut Shell Liquid (CNSL), has a variety of industrial uses which were first developed in the 1930s. CNSL is fractionated in a process similar to the distillation of petroleum, and has two primary end products: solids that are pulverized and used as friction particle for brake linings, and an amber-colored liquid that is aminated to create phenalkamine curing agents and resin modifiers. Phenalkamines are primarily used in epoxy coatings for the marine and flooring markets, as they have intense hydrophobic properties and are capable of remaining chemically active at low temperatures. | Cashew
The cashew (Anacardium occidentale; syn. Anacardium curatellifolium A.St.-Hil.) is a tree in the flowering plant family Anacardiaceae. The plant is native to northeastern Brazil, where it is called by its Portuguese name Caju (the fruit) or Cajueiro (the tree). It is now widely grown in tropical climates for its cashew "nuts" (see below) and cashew apples.
It is a small evergreen tree growing to 10-12 m tall, with a short, often irregularly-shaped trunk. The leaves are spirally arranged, leathery textured, elliptic to obovate, 4 to 22 cm long and 2 to 15 cm broad, with a smooth margin. The flowers are produced in a panicle or corymb up to 26 cm long, each flower small, pale green at first then turning reddish, with five slender, acute petals 7 to 15 mm long.
What appears to be the fruit of the cashew tree is an oval or pear-shaped accessory fruit or false fruit that develops from the receptacle of the cashew flower. Called the cashew apple, better known in Central America as "marañón", it ripens into a yellow and/or red structure about 5–11 cm long.
The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the pseudofruit. Actually, the drupe develops first on the tree, and then the peduncle expands into the pseudofruit. Within the true fruit is a single seed, the cashew nut. Although a nut in the culinary sense, in the botanical sense the fruit of the cashew is a seed. The seed is surrounded by a double shell containing a caustic phenolic resin, urushiol, a potent skin irritant toxin also found in the related poison ivy. Some people are allergic to cashews, but cashews are a less frequent allergen than some nuts.
Other vernacular names include cajueiro, cashu, casho, acajuiba, caju, acajou, acaju, acajaiba, alcayoiba, anacarde, anacardier, anacardo, cacajuil, cajou, gajus, godambi (in Kannada), jeedi pappu (in Telugu), jocote maranon, maranon, merey, noix d’acajou, pomme cajou, pomme, jambu, jambu golok, jambu mete, jambu monyet, jambu terong, kasoy. In the Antilles, specifically Puerto Rico, it is known as pajuil and the pseudofruit is the main used part as raw fruit.
# Cashew Industry
Originally spread from Brazil by the Portuguese, the cashew tree is now cultivated in all regions with a sufficiently warm and humid climate.
Cashew is produced in around 32 countries of the world. The world production figures of cashew crop, published by FAO, was around 2.7 million tons per annum. The major raw cashew producing countries with their production figures in 2005 (as per the UN's Food and Agriculture Organization) are Vietnam (960,800 tons), Nigeria (594,000), India (460,000 tons), Brazil (147,629 tons) and Indonesia (122,000 tons).
World’s total area under the cultivation of cashew is around 35,100 km². India ranks first in area utilized for cashew production, though its yields are relatively low. The world’s average yield is 700 pounds per acre (780 kg/hectare) of land
Collectively, Vietnam, India and Brazil account for more than 90% of all cashew kernel exports. Some varieties of cashews come from Kollam or Quilon in Kerala, Southern India which alone produces 4,000 tons of cashews per annum. The major trading centers of cashew in India are Palasa, Kollam or Quilon Mangalore and Kochi.
# Uses
The cashew apple is used for its juicy but acidic pulp, which can be eaten raw or used in the production of jam, chutney, or various beverages. Depending on local customs, its juice is also processed and distilled into liquor or consumed diluted and sugared as a refreshing drink, Cajuína. Ripe cashew apples also make good caipirinha. In Goa, India, the cashew apple is the source of juicy pulp used to prepare fenny, a locally popular distilled liquor. In Nicaragua the cashew apple has many uses, it is often eaten or made into juice and also processed to create sweets and jellies. Other uses in Nicaragua include fermentation to produce wine and home-vinegar.[1] The cashew apple contains much tannin and is very perishable. For this reason, in many parts of the world, the false fruit is simply discarded after removal of the cashew nut.
The urushiol must be removed from the dark green nut shells before the seed inside is processed for consumption; this is done by shelling the nuts, a somewhat hazardous process, and exceedingly painful skin rashes (similar to poison-ivy rashes) among processing workers are common. In India urushiol is traditionally used to control tamed elephants by their mahouts (riders or keepers). The so-called "raw cashews" available in health food shops have been cooked but not roasted or browned.
Cashew nuts are a common ingredient in Asian cooking. They can also be ground into a spread called cashew butter similar to peanut butter. Cashews have a very high oil content, and they are used in some other nut butters to add extra oil. Cashews contain 180 calories per ounce (6 calories per gram), 70% of which are from fat.
The liquid contained within the shell casing of the cashew, known as Cashew Nut Shell Liquid (CNSL), has a variety of industrial uses which were first developed in the 1930s. CNSL is fractionated in a process similar to the distillation of petroleum, and has two primary end products: solids that are pulverized and used as friction particle for brake linings, and an amber-colored liquid that is aminated to create phenalkamine curing agents and resin modifiers. Phenalkamines are primarily used in epoxy coatings for the marine and flooring markets, as they have intense hydrophobic properties and are capable of remaining chemically active at low temperatures. | https://www.wikidoc.org/index.php/Cashew | |
e2373ecac90e8942cc9f3c828a140360c39cda4c | wikidoc | Cassia | Cassia
Cassia (Cinnamomum aromaticum, synonym C. cassia) is an evergreen tree native to southern China, Bangladesh, India, and Vietnam. Like its close relative, cinnamon (Cinnamomum zeylanicum, also known as "true cinnamon" or "Ceylon cinnamon"), it is used primarily for its aromatic bark, which is used as a spice, often under the culinary name of "cinnamon". The buds are also used as a spice, especially in India and in Ancient Rome.
The Cassia tree grows to 10-15 m tall, with greyish bark and hard elongated leaves that are 10-15 cm long and have a decidedly reddish colour when young.
# Production and uses
Cassia is a close relative to the cinnamon (Cinnamomum verum, Cinnamomum zeylanicum, or "true cinnamon"), Saigon cinnamon (Cinnamomum loureiroi, also known as "Vietnamese cinnamon"), Camphor laurel (Cinnamomum camphora), Malabathrum (Cinnamomum tamala) and Cinnamomum burmannii (also know as "Indonesian cinnamon") trees. As with these species, the dried bark of cassia is used as a spice. Cassia's flavour, however, is less delicate than that of true cinnamon; for this reason, the less expensive cassia is sometimes called "bastard cinnamon".
Whole branches and small trees are harvested for cassia bark, unlike the small shoots used in the production of cinnamon; this gives cassia bark a much thicker and rougher texture than that of true cinnamon.
Most of the spice sold as cinnamon in the United States and Canada (where true cinnamon is still generally unknown) is actually cassia. In some cases, cassia is labeled "Chinese cinnamon" to distinguish it from the more expensive true cinnamon (Cinnamomum zeylanicum), which is the preferred form of the spice used in Mexico and Europe .
"Indonesian cinnamon" can also refer to Cinnamomum burmannii, which is also
commonly sold in the United States, labeled only as cinnamon.
Cassia (Cinnamomum aromaticum) is produced in both China and Vietnam. Until the 1960s, Vietnam was the world's most important producer of Saigon cinnamon, a species which has a higher oil content than Cinnamomum aromaticum, and consequently has a stronger flavor. Saigon cinnamon is so closely related to cassia that it was often marketed as cassia (or, in North America, "cinnamon"). Of the three forms of cassia, it is the form which commands the highest price. Because of the disruption caused by the Vietnam War, however, production of another form of cassia, Cinnamomum burmannii, in the highlands of the Indonesia on island of Sumatra was increased to meet demand, and Indonesia remains one of the main exporters of cassia today. Indonesia cassia has the lowest oil content of the three types of cassia and, consequently, commands the lowest price. Saigon cinnamon, only having become available again in the United States since the early 21st century, has an intense flavour and aroma and a higher percentage of essential oils than Indonesian cassia. Cinnamomum aromaticum has a stronger and sweeter flavor, similar to Saigon cinnamon, although the oil content is lower. In China, cassia is known as Tung Hing.
Cassia bark (both powdered and in whole, or "stick" form) is used as a flavouring agent for candies, desserts, baked goods, and meat; it is specified in many curry recipes, where cinnamon is less suitable. Cassia is sometimes added to true cinnamon but is a much thicker, coarser product. Cassia is sold as pieces of bark (as pictured below) or as neat quills or sticks. Cassia sticks can be distinguished from true cinnamon sticks in the following manner: Cinnamon sticks have many thin layers and can easily be made into powder using a coffee or spice grinder, whereas cassia sticks are extremely hard, are usually made up of one thick layer, and can break an electric spice or coffee grinder if one attempts to grind them without first breaking them into very small pieces.
Cassia buds, although rare, are also occasionally used as a spice. They resemble cloves in appearance and flavor.photo
## Health benefits and risks
Cassia (called ròu gùi; 肉桂 in Chinese) is used in traditional Chinese medicine, where it is considered one of the 50 fundamental herbs.
A 2003 study published in the DiabetesCare journal followed Type 2 diabetics ingesting 1, 3, or 6 grams of cassia daily. Those taking 6 grams showed changes after 20 days, and those taking lesser doses showed changes after 40 days. Regardless of the amount of cassia taken, they reduced their mean fasting serum glucose levels 18–29%, their triglyceride levels 23–30%, their LDL cholesterol 7–27%, and their total cholesterol 12–26%, compared to others taking placebos.
The effects, which may even be produced by brewing a tea from cassia bark, may also be beneficial for non-diabetics to prevent and control elevated glucose, insulin, and blood lipid levels. However, chemist Richard Anderson says that his research has shown that most, if not all, of cinnamon's antidiabetic effect is in its water-soluble fraction, not the oil (the ground cinnamon spice itself should be ingested for benefit, not the oil or a water extraction). In fact, some cinnamon oil-entrained compounds could prove toxic in high concentrations. Cassia's effects on enhancing insulin sensitivity appear to be mediated by polyphenols . Despite these findings, cassia should not be used in place of anti-diabetic drugs, unless blood glucose levels are closely monitored, and its use is combined with a strictly controlled diet and exercise program.
Researchers at the University of California, Santa Barbara have discovered an extract of common cinnamon that contains a class of small organic molecules that inhibit several key processes in Alzheimer’s disease. The cinnamon extract inhibits the aggregation of tau and disassembles fibers that have already formed, suggesting that neurofibrillary tangles can possibly be reversed by these compounds. The extract exhibits potent inhibitory activity, is orally available, water-soluble, non-toxic, and the bioactive molecules are likely brain permeable. The extract is readily produced in large quantities and can be encapsulated in powder form for oral
administration. These properties make the cinnamon extract a highly favourable substance for development into an effective therapeutic to slow or prevent Alzheimer’s disease.
There is also much anecdotal evidence that consumption of cassia has a strong effect in lowering blood pressure, making it potentially useful to those suffering from hypertension. The USDA has three ongoing studies that are monitoring the blood pressure effect.
Though the spice has been used for thousands of years, there is concern that there is as yet no knowledge about the potential for toxic buildup of the fat-soluble components in cassia, as anything fat-soluble could potentially be subject to toxic buildup. There are no concluded long-term clinical studies on the use of cassia for health reasons.
Due to a toxic component called coumarin, European health agencies have warned against consuming high amounts of cassia.
# History
In classical times, four types of cinnamon were distinguished (and often confused):
- Cassia (Hebrew qəṣi`â), the bark of Cinnamomum iners from Arabia and Ethiopia
- Cinnamon proper (Hebrew qinnamon), the bark of Cinnamomum zeylanicum from Sri Lanka
- Malabathrum or Malobathrum (from Sanskrit तमालपत्त्रम्, tamālapattram, literally "dark-tree leaves"), Cinnamomum malabathrum from the North of India
- Serichatum, Cinnamomum aromaticum from Seres, that is, China.
In Exodus 30:23-4, Moses is ordered to use both sweet cinnamon (Kinnamon) and cassia (qəṣî`â) together with myrrh and cannabis
or sweet calamus (qənê-bosem, literally cane of fragrance) and olive oil to produce a holy oil to anoint the Ark of the Covenant. Psalm 45, 8, mentions the garments of Torah scholars that smell of myrrh, aloes and cassia.
An early reference to the trade of cinnamon occurs around 100 BC in Chinese literature. After the explorer Zhang Qian's return to China, the Han Dynasty pushed the Xiongnu back and trade and cultural exchange flourished along the Northern Silk Road. Goods moving by caravan to the west included gold, rubies, jade, textiles, coral, ivory and art works. In the opposite direction moved bronze weapons, furs, ceramics and cinnamon bark. The first Greek reference to kasia is found in a poem by Sappho in the 7th century B.C.
According to Herodotus, both cinnamon and cassia grow in Arabia, together with incense, myrrh, and ladanum, and are guarded by winged serpents. The phoenix builds its nest from cinnamon and cassia. But Herodotus mentions other writers that see the home of Dionysos, e.g., India, as the source of cassia. While Theophrastus gives a rather good account of the plants, a curious method for harvesting (worms eat away the wood and leave the bark behind), Dioscorides seems to confuse the plant with some kind of water-lily.
Pliny (nat. 12, 86-87) gives a fascinating account of the early spice trade across the Red Sea in "rafts without sails or oars", obviously using the trade winds, that costs Rome 100 million sesterces each year. According to Pliny, a pound (the Roman pound, 327 g) of cassia, cinnamon, or serichatum cost up to 300 denars, the wage of ten months' labour. Diocletian's Edict on Maximum Prices from 301 AD gives a price of 125 denars for a pound of cassia, while an agricultural labourer earned 25 denars per day.
The Greeks used kásia or malabathron to flavour wine, together with absinth (Artemisia absinthia). Pliny mentions cassia as a flavouring agent for wine as well Malabathrum leaves (folia) were used in cooking and for distilling an oil used in a caraway-sauce for oysters by the Roman gourmet Gaius Gavius Apicius. Malabathrum is among the spices that, according to Apicius, any good kitchen should contain.
Egyptian recipes for kyphi, an aromatic used for burning, included cinnamon and cassia from Hellenistic times onwards. The gifts of Hellenistic rulers to temples sometimes included cassia and cinnamon as well as incense, myrrh, and Indian incense (kostos), so we can conclude that the Greeks used it in this way too.
The famous Commagenum, an unguent produced in Commagene in present-day eastern Turkey, was made from goose-fat and aromatised with cinnamon oil and spikenard (Nardostachys jatamansi). Malobrathum from Egypt (Dioscorides I, 63) was based on cattle-fat and contained cinnamon as well; one pound cost 300 denars. The Roman poet Martial (VI, 55) makes fun of Romans who drip unguents, smell of cassia and cinnamon taken from a bird's nest, and look down on him who does not smell at all.
Cinnamon, as a warm and dry substance, was believed by doctors in ancient times to cure snakebites, freckles, the common cold, and kidney troubles, among other ailments. | Cassia
Cassia (Cinnamomum aromaticum, synonym C. cassia) is an evergreen tree native to southern China, Bangladesh, India, and Vietnam. Like its close relative, cinnamon (Cinnamomum zeylanicum, also known as "true cinnamon" or "Ceylon cinnamon"), it is used primarily for its aromatic bark, which is used as a spice, often under the culinary name of "cinnamon". The buds are also used as a spice, especially in India and in Ancient Rome.
The Cassia tree grows to 10-15 m tall, with greyish bark and hard elongated leaves that are 10-15 cm long and have a decidedly reddish colour when young.
# Production and uses
Cassia is a close relative to the cinnamon (Cinnamomum verum, Cinnamomum zeylanicum, or "true cinnamon"), Saigon cinnamon (Cinnamomum loureiroi, also known as "Vietnamese cinnamon"), Camphor laurel (Cinnamomum camphora), Malabathrum (Cinnamomum tamala) and Cinnamomum burmannii (also know as "Indonesian cinnamon") trees. As with these species, the dried bark of cassia is used as a spice. Cassia's flavour, however, is less delicate than that of true cinnamon; for this reason, the less expensive cassia is sometimes called "bastard cinnamon".[1]
Whole branches and small trees are harvested for cassia bark, unlike the small shoots used in the production of cinnamon; this gives cassia bark a much thicker and rougher texture than that of true cinnamon.
Most of the spice sold as cinnamon in the United States and Canada (where true cinnamon is still generally unknown) is actually cassia. In some cases, cassia is labeled "Chinese cinnamon" to distinguish it from the more expensive true cinnamon (Cinnamomum zeylanicum), which is the preferred form of the spice used in Mexico and Europe [1].
"Indonesian cinnamon" can also refer to Cinnamomum burmannii, which is also
commonly sold in the United States, labeled only as cinnamon.
Cassia (Cinnamomum aromaticum) is produced in both China and Vietnam. Until the 1960s, Vietnam was the world's most important producer of Saigon cinnamon, a species which has a higher oil content than Cinnamomum aromaticum, and consequently has a stronger flavor. Saigon cinnamon is so closely related to cassia that it was often marketed as cassia (or, in North America, "cinnamon"). Of the three forms of cassia, it is the form which commands the highest price. Because of the disruption caused by the Vietnam War, however, production of another form of cassia, Cinnamomum burmannii, in the highlands of the Indonesia on island of Sumatra was increased to meet demand, and Indonesia remains one of the main exporters of cassia today. Indonesia cassia has the lowest oil content of the three types of cassia and, consequently, commands the lowest price. Saigon cinnamon, only having become available again in the United States since the early 21st century, has an intense flavour and aroma and a higher percentage of essential oils than Indonesian cassia. Cinnamomum aromaticum has a stronger and sweeter flavor, similar to Saigon cinnamon, although the oil content is lower. In China, cassia is known as Tung Hing. [2]
Cassia bark (both powdered and in whole, or "stick" form) is used as a flavouring agent for candies, desserts, baked goods, and meat; it is specified in many curry recipes, where cinnamon is less suitable. Cassia is sometimes added to true cinnamon but is a much thicker, coarser product. Cassia is sold as pieces of bark (as pictured below) or as neat quills or sticks. Cassia sticks can be distinguished from true cinnamon sticks in the following manner: Cinnamon sticks have many thin layers and can easily be made into powder using a coffee or spice grinder, whereas cassia sticks are extremely hard, are usually made up of one thick layer, and can break an electric spice or coffee grinder if one attempts to grind them without first breaking them into very small pieces.
Cassia buds, although rare, are also occasionally used as a spice. They resemble cloves in appearance and flavor.[3]photo
## Health benefits and risks
Cassia (called ròu gùi; 肉桂 in Chinese) is used in traditional Chinese medicine, where it is considered one of the 50 fundamental herbs.
A 2003 study published in the DiabetesCare journal[2] followed Type 2 diabetics ingesting 1, 3, or 6 grams of cassia daily. Those taking 6 grams showed changes after 20 days, and those taking lesser doses showed changes after 40 days. Regardless of the amount of cassia taken, they reduced their mean fasting serum glucose levels 18–29%, their triglyceride levels 23–30%, their LDL cholesterol 7–27%, and their total cholesterol 12–26%, compared to others taking placebos.
The effects, which may even be produced by brewing a tea from cassia bark, may also be beneficial for non-diabetics to prevent and control elevated glucose, insulin, and blood lipid levels. However, chemist Richard Anderson says that his research has shown that most, if not all, of cinnamon's antidiabetic effect is in its water-soluble fraction, not the oil (the ground cinnamon spice itself should be ingested for benefit, not the oil or a water extraction). In fact, some cinnamon oil-entrained compounds could prove toxic in high concentrations. Cassia's effects on enhancing insulin sensitivity appear to be mediated by polyphenols [4]. Despite these findings, cassia should not be used in place of anti-diabetic drugs, unless blood glucose levels are closely monitored, and its use is combined with a strictly controlled diet and exercise program.
Researchers at the University of California, Santa Barbara have discovered an extract of common cinnamon that contains a class of small organic molecules that inhibit several key processes in Alzheimer’s disease. The cinnamon extract inhibits the aggregation of tau and disassembles fibers that have already formed, suggesting that neurofibrillary tangles can possibly be reversed by these compounds. The extract exhibits potent inhibitory activity, is orally available, water-soluble, non-toxic, and the bioactive molecules are likely brain permeable. The extract is readily produced in large quantities and can be encapsulated in powder form for oral
administration. These properties make the cinnamon extract a highly favourable substance for development into an effective therapeutic to slow or prevent Alzheimer’s disease.[3]
There is also much anecdotal evidence that consumption of cassia has a strong effect in lowering blood pressure, making it potentially useful to those suffering from hypertension. The USDA has three ongoing studies that are monitoring the blood pressure effect.
Though the spice has been used for thousands of years, there is concern that there is as yet no knowledge about the potential for toxic buildup of the fat-soluble components in cassia, as anything fat-soluble could potentially be subject to toxic buildup. There are no concluded long-term clinical studies on the use of cassia for health reasons.
Due to a toxic component called coumarin, European health agencies have warned against consuming high amounts of cassia.[4]
# History
In classical times, four types of cinnamon were distinguished (and often confused):
- Cassia (Hebrew qəṣi`â), the bark of Cinnamomum iners from Arabia and Ethiopia
- Cinnamon proper (Hebrew qinnamon), the bark of Cinnamomum zeylanicum from Sri Lanka
- Malabathrum or Malobathrum (from Sanskrit तमालपत्त्रम्, tamālapattram, literally "dark-tree leaves"), Cinnamomum malabathrum from the North of India
- Serichatum, Cinnamomum aromaticum from Seres, that is, China.
In Exodus 30:23-4, Moses is ordered to use both sweet cinnamon (Kinnamon) and cassia (qəṣî`â) together with myrrh and cannabis [5]
[6] or sweet calamus (qənê-bosem, literally cane of fragrance) and olive oil to produce a holy oil to anoint the Ark of the Covenant. Psalm 45, 8, mentions the garments of Torah scholars that smell of myrrh, aloes and cassia.
An early reference to the trade of cinnamon occurs around 100 BC in Chinese literature. After the explorer Zhang Qian's return to China, the Han Dynasty pushed the Xiongnu back and trade and cultural exchange flourished along the Northern Silk Road. Goods moving by caravan to the west included gold, rubies, jade, textiles, coral, ivory and art works. In the opposite direction moved bronze weapons, furs, ceramics and cinnamon bark.[7] The first Greek reference to kasia is found in a poem by Sappho in the 7th century B.C.
According to Herodotus, both cinnamon and cassia grow in Arabia, together with incense, myrrh, and ladanum, and are guarded by winged serpents. The phoenix builds its nest from cinnamon and cassia. But Herodotus mentions other writers that see the home of Dionysos, e.g., India, as the source of cassia. While Theophrastus gives a rather good account of the plants, a curious method for harvesting (worms eat away the wood and leave the bark behind), Dioscorides seems to confuse the plant with some kind of water-lily.
Pliny (nat. 12, 86-87) gives a fascinating account of the early spice trade across the Red Sea in "rafts without sails or oars", obviously using the trade winds, that costs Rome 100 million sesterces each year. According to Pliny, a pound (the Roman pound, 327 g) of cassia, cinnamon, or serichatum cost up to 300 denars, the wage of ten months' labour. Diocletian's Edict on Maximum Prices[8] from 301 AD gives a price of 125 denars for a pound of cassia, while an agricultural labourer earned 25 denars per day.
The Greeks used kásia or malabathron to flavour wine, together with absinth (Artemisia absinthia). Pliny mentions cassia as a flavouring agent for wine as well[9] Malabathrum leaves (folia) were used in cooking and for distilling an oil used in a caraway-sauce for oysters by the Roman gourmet Gaius Gavius Apicius.[10] Malabathrum is among the spices that, according to Apicius, any good kitchen should contain.
Egyptian recipes for kyphi, an aromatic used for burning, included cinnamon and cassia from Hellenistic times onwards. The gifts of Hellenistic rulers to temples sometimes included cassia and cinnamon as well as incense, myrrh, and Indian incense (kostos), so we can conclude that the Greeks used it in this way too.
The famous Commagenum, an unguent produced in Commagene in present-day eastern Turkey, was made from goose-fat and aromatised with cinnamon oil and spikenard (Nardostachys jatamansi). Malobrathum from Egypt (Dioscorides I, 63) was based on cattle-fat and contained cinnamon as well; one pound cost 300 denars. The Roman poet Martial (VI, 55) makes fun of Romans who drip unguents, smell of cassia and cinnamon taken from a bird's nest, and look down on him who does not smell at all.
Cinnamon, as a warm and dry substance, was believed by doctors in ancient times to cure snakebites, freckles, the common cold, and kidney troubles, among other ailments. | https://www.wikidoc.org/index.php/Cassia | |
8dd4d2eb233117138db100d5a7ac9337794dfa1f | wikidoc | Nepeta | Nepeta
Nepeta is a genus of about 250 species of flowering plants in the family Lamiaceae. The members of this group are known as catnips or catmints due to its famed liking by cats—nepeta pleasantly stimulates cats' pheromonic receptor. The genus is native to Europe, Asia, and Africa, with the highest species diversity in the Mediterranean region east to mainland China. It is now common in North America as a weed. Most of the species are herbaceous perennial plants, but some are annuals. They have sturdy stems with opposite heart-shaped, green to grayish-green leaves. The flowers are white, blue, pink, or lilac and occur in several clusters toward the tip of the stems. The flowers are tubular shaped and are spotted with tiny purple dots. The scent of the plant has a stimulating effect on cats.
Also, oil isolated from catnip by steam distillation is a repellent against insects, in particular mosquitoes, cockroaches and termites. Research suggests that while in a test tube, distilled nepetalactone, the active ingredient in catnip, repels mosquitoes 10 times more effectively than DEET, the active ingredient in most insect repellents, as a repellant on skin it is not as effective.
# Effects on cats
Catnip and catmints are mainly known for their behavioral effects they have on cats, particularly domestic cats. Both true catnip and Faassen's catnip have a sharp, biting taste, while the taste of giant catmint is bland. Approximately two thirds of cats are susceptible to the behavioral effects of catnip, as the phenomenon is hereditary. For example, most cats in Australia are not susceptible to catnip since Australian cats are drawn from a relatively closed genetic pool. The fact that it only elicits such a response in a proportion of cats — and that it is such a dramatic response — suggests that a genetic element is involved that is enriched in domesticated breeds.
When cats sense the bruised leaves or stems of catnip, they may roll over it, paw at it, chew it, lick it, leap about and purr, often salivating copiously. Some cats will also growl and meow. This reaction only lasts for a few minutes before the cat loses interest. It takes up to two hours for the cat to "reset" after which it can come back to the catnip and have the same response as before. Young kittens and older cats are less likely to have a reaction to catnip.
There is some disagreement about the susceptibility of lions and tigers to catnip. Some claim that all lions and tigers are effected by catnip but there are others who state that this is not true.
Catnip contains nepetalactone, a terpene. Nepetalactone can be extracted from catnip using steam distillation. Cats detect it through their olfactory epithelium and not through their vomeronasal organ . At the olfactory epithelium, the nepetalactone is hypothesized to bind to one or more olfactory receptors where it probably mimicks a pheromone, such as the hypothetical feline facial pheromone.
Other plants that also have this effect on cats include valerian (Valeriana officinalis) and plants that contain actinidine or dihydroactinidiolide (Smith, 2005).
# Species
Nepeta cataria (Catnip, True Catnip, Catmint or Field Balm) is a 50–100 cm tall herb resembling mint in appearance, with greyish-green leaves; the flowers are white, finely spotted with purple. It has been introduced to many countries, and is now a widespread weed in some areas, including the United States. A lemon-scented cultivar, N. cataria 'Citriodora' looks exactly like true catnip, but has the scent of lemons, and can be used like Lemon balm.
Nepeta grandiflora (Giant Catmint or Caucasus Catmint) is lusher than true catnip, and has dark green leaves and dark blue, almost purple flowers.
Nepeta × faassenii (N. racemosa × N. nepetella; Faassen's Nepeta or Faassen's Catnip) is mostly grown as an ornamental plant. This hybrid is far smaller than either of above, and is almost a ground cover. It has greyish-green leaves and light purple flowers.
Some Dracocephalum, Glechoma and Calamintha species were formerly classified in Nepeta.
Nepeta species are used as food plants by the larvae of some Lepidoptera species including Coleophora albitarsella. | Nepeta
Nepeta is a genus of about 250 species of flowering plants in the family Lamiaceae. The members of this group are known as catnips or catmints due to its famed liking by cats—nepeta pleasantly stimulates cats' pheromonic receptor. The genus is native to Europe, Asia, and Africa, with the highest species diversity in the Mediterranean region east to mainland China. It is now common in North America as a weed[1]. Most of the species are herbaceous perennial plants, but some are annuals. They have sturdy stems with opposite heart-shaped, green to grayish-green leaves. The flowers are white, blue, pink, or lilac and occur in several clusters toward the tip of the stems. The flowers are tubular shaped and are spotted with tiny purple dots. The scent of the plant has a stimulating effect on cats.
Also, oil isolated from catnip by steam distillation is a repellent against insects, in particular mosquitoes, cockroaches and termites.[2][3] Research suggests that while in a test tube, distilled nepetalactone, the active ingredient in catnip, repels mosquitoes 10 times more effectively than DEET, the active ingredient in most insect repellents,[4][5] as a repellant on skin it is not as effective.[6]
# Effects on cats
Catnip and catmints are mainly known for their behavioral effects they have on cats, particularly domestic cats. Both true catnip and Faassen's catnip have a sharp, biting taste, while the taste of giant catmint is bland. Approximately two thirds of cats are susceptible to the behavioral effects of catnip, as the phenomenon is hereditary. For example, most cats in Australia are not susceptible to catnip since Australian cats are drawn from a relatively closed genetic pool.[7] The fact that it only elicits such a response in a proportion of cats — and that it is such a dramatic response — suggests that a genetic element is involved that is enriched in domesticated breeds.[citation needed]
When cats sense the bruised leaves or stems of catnip, they may roll over it, paw at it, chew it, lick it, leap about and purr, often salivating copiously. Some cats will also growl and meow. This reaction only lasts for a few minutes before the cat loses interest. It takes up to two hours for the cat to "reset" after which it can come back to the catnip and have the same response as before. Young kittens and older cats are less likely to have a reaction to catnip.
There is some disagreement about the susceptibility of lions and tigers to catnip. Some claim that all lions and tigers are effected by catnip[8] but there are others who state that this is not true.[7]
Catnip contains nepetalactone, a terpene. Nepetalactone can be extracted from catnip using steam distillation[9]. Cats detect it through their olfactory epithelium and not through their vomeronasal organ [10]. At the olfactory epithelium, the nepetalactone is hypothesized to bind to one or more olfactory receptors where it probably mimicks a pheromone, such as the hypothetical feline facial pheromone.
Other plants that also have this effect on cats include valerian (Valeriana officinalis) and plants that contain actinidine or dihydroactinidiolide (Smith, 2005).
# Species
Nepeta cataria (Catnip, True Catnip, Catmint or Field Balm) is a 50–100 cm tall herb resembling mint in appearance, with greyish-green leaves; the flowers are white, finely spotted with purple. It has been introduced to many countries, and is now a widespread weed in some areas, including the United States. A lemon-scented cultivar, N. cataria 'Citriodora' looks exactly like true catnip, but has the scent of lemons, and can be used like Lemon balm.
Nepeta grandiflora (Giant Catmint or Caucasus Catmint) is lusher than true catnip, and has dark green leaves and dark blue, almost purple flowers.
Nepeta × faassenii (N. racemosa × N. nepetella; Faassen's Nepeta or Faassen's Catnip) is mostly grown as an ornamental plant. This hybrid is far smaller than either of above, and is almost a ground cover. It has greyish-green leaves and light purple flowers.
Some Dracocephalum, Glechoma and Calamintha species were formerly classified in Nepeta.
Nepeta species are used as food plants by the larvae of some Lepidoptera species including Coleophora albitarsella. | https://www.wikidoc.org/index.php/Catnip | |
74c8f24c034e2c23d21754da3edeef7b1d59607d | wikidoc | Cav1.1 | Cav1.1
Cav1.1 also known as the calcium channel, voltage-dependent, L type, alpha 1S subunit, (CACNA1S), is a protein which in humans is encoded by the CACNA1S gene. It is also known as CACNL1A3 and the dihydropyridine receptor (DHPR, so named due to the blocking action DHP has on it).
# Function
This gene encodes one of the five subunits of the slowly inactivating L-type voltage-dependent calcium channel in skeletal muscle cells. Mutations in this gene have been associated with hypokalemic periodic paralysis, thyrotoxic periodic paralysis and malignant hyperthermia susceptibility.
Cav1.1 is a voltage-dependent calcium channel found in the transverse tubule of muscles. In skeletal muscle it associates with the ryanodine receptor RyR1 of the sarcoplasmic reticulum via a mechanical linkage. It senses the voltage change caused by the end-plate potential from nervous stimulation and propagated by sodium channels as action potentials to the T-tubules. It was previously thought that when the muscle depolarises, the calcium channel opens, allowing calcium in and activating RyR1, which mediates much greater calcium release from the sarcoplasmic reticulum. This is the first part of the process of excitation-contraction coupling, which ultimately causes the muscle to contract. Calcium entry through Cav1.1 is not required in skeletal muscle, as it is in cardiac muscle; Cav1.1 undergoes a conformational change which allosterically activates RyR1.
# Clinical significance
In hypokalemic periodic paralysis (HOKPP), the voltage sensors in domains 2 and 4 of Cav1.1 are mutated (loss-of-function), reducing the availability of the channel to sense depolarisation, and therefore it cannot activate the ryanodine receptor as efficiently. As a result, the muscle cannot contract very well and the patient is paralysed. The condition is hypokalemic because a low extracellular potassium ion concentration will cause the muscle to repolarise to the resting potential more quickly, so any calcium conductance that does occur cannot be sustained. It becomes more difficult to reach the threshold at which the muscle can contract, and even if this is reached then the muscle is more prone to relaxing. Because of this, the severity would be reduced if potassium ion concentrations are maintained. In contrast, hyperkalemic periodic paralysis refers to gain-of-function mutations in sodium channels that maintain muscle depolarisation and therefore are aggravated by high potassium ion concentrations.
The European Malignant Hyperthermia Group accepts two mutations in CACNA1S as diagnostic for malignant hyperthermia.
# Blockers
Cav1.1 is blocked by dihydropyridine. | Cav1.1
Cav1.1 also known as the calcium channel, voltage-dependent, L type, alpha 1S subunit, (CACNA1S), is a protein which in humans is encoded by the CACNA1S gene.[1] It is also known as CACNL1A3 and the dihydropyridine receptor (DHPR, so named due to the blocking action DHP has on it).
# Function
This gene encodes one of the five subunits of the slowly inactivating L-type voltage-dependent calcium channel in skeletal muscle cells. Mutations in this gene have been associated with hypokalemic periodic paralysis, thyrotoxic periodic paralysis and malignant hyperthermia susceptibility.[1]
Cav1.1 is a voltage-dependent calcium channel found in the transverse tubule of muscles. In skeletal muscle it associates with the ryanodine receptor RyR1 of the sarcoplasmic reticulum via a mechanical linkage. It senses the voltage change caused by the end-plate potential from nervous stimulation and propagated by sodium channels as action potentials to the T-tubules. It was previously thought that when the muscle depolarises, the calcium channel opens, allowing calcium in and activating RyR1, which mediates much greater calcium release from the sarcoplasmic reticulum. This is the first part of the process of excitation-contraction coupling, which ultimately causes the muscle to contract. Calcium entry through Cav1.1 is not required in skeletal muscle, as it is in cardiac muscle; Cav1.1 undergoes a conformational change which allosterically activates RyR1.[2]
# Clinical significance
In hypokalemic periodic paralysis (HOKPP), the voltage sensors in domains 2 and 4 of Cav1.1 are mutated (loss-of-function), reducing the availability of the channel to sense depolarisation, and therefore it cannot activate the ryanodine receptor as efficiently. As a result, the muscle cannot contract very well and the patient is paralysed. The condition is hypokalemic because a low extracellular potassium ion concentration will cause the muscle to repolarise to the resting potential more quickly, so any calcium conductance that does occur cannot be sustained. It becomes more difficult to reach the threshold at which the muscle can contract, and even if this is reached then the muscle is more prone to relaxing. Because of this, the severity would be reduced if potassium ion concentrations are maintained. In contrast, hyperkalemic periodic paralysis refers to gain-of-function mutations in sodium channels that maintain muscle depolarisation and therefore are aggravated by high potassium ion concentrations.[3]
The European Malignant Hyperthermia Group accepts two mutations in CACNA1S as diagnostic for malignant hyperthermia.[4]
# Blockers
Cav1.1 is blocked by dihydropyridine. | https://www.wikidoc.org/index.php/Cav1.1 | |
94a0f05e21d893f8449e7e7e3bf8ef5510b1c858 | wikidoc | Cav1.2 | Cav1.2
Calcium channel, voltage-dependent, L type, alpha 1C subunit (also known as Cav1.2) is a protein that in humans is encoded by the CACNA1C gene. Cav1.2 is a subunit of L-type voltage-dependent calcium channel.
# Structure and function
This gene encodes an alpha-1 subunit of a voltage-dependent calcium channel. Calcium channels mediate the influx of calcium ions (Ca2+) into the cell upon membrane polarization (see membrane potential and calcium in biology).
The alpha-1 subunit consists of 24 transmembrane segments and forms the pore through which ions pass into the cell. The calcium channel consists of a complex of alpha-1, alpha-2/delta and beta subunits in a 1:1:1 ratio. The S3-S4 linkers of Cav1.2 determine the gating phenotype and modulated gating kinetics of the channel. Cav1.2 is widely expressed in the smooth muscle, pancreatic cells, fibroblasts, and neurons. However, it is particularly important and well known for its expression in the heart where it mediates L-type currents, which causes calcium-induced calcium release from the ER Stores via ryanodine receptors. It depolarizes at -30mV and helps define the shape of the action potential in cardiac and smooth muscle. The protein encoded by this gene binds to and is inhibited by dihydropyridine. In the arteries of the brain, high levels of calcium in mitochondria elevates activity of nuclear factor kappa B NF-κB and transcription of CACNA1c and functional Cav1.2 expression increases. Cav1.2 also regulates levels of osteoprotegerin.
CaV1.2 is inhibited by the action of STIM1.
# Regulation
The activity of CaV1.2 channels is tightly regulated by the Ca2+ signals they produce. An increase in intracellular Ca2+ concentration implicated in Cav1.2 facilitation, a form of positive feedback called Ca2+-dependent facilitation, that amplifies Ca2+ influx. In addition, increasing influx intracellular Ca2+ concentration has implicated to exert the opposite effect Ca2+ dependent inactivation. These activation and inactivation mechanisms both involve Ca2+ binding to calmodulin (CaM) in the IQ domain in the C-terminal tail of these channels. Cav1.2 channels are arranged in cluster of eight, on average, in the cell membrane. When calcium ions bind to calmodulin, which in turn binds to a Cav1.2 channel, it allows the Cav1.2 channels within a cluster to interact with each other. This results in channels working cooperatively when they open at the same time to allow more calcium ions to enter and then close together to allow the cell to relax.
# Clinical significance
Mutation in the CACNA1C gene, the single-nucleotide polymorphism located in the third intron of the Cav1.2 gene, are associated with a variant of Long QT syndrome called Timothy's syndrome and also with Brugada syndrome. Large-scale genetic analyses have shown the possibility that CACNA1C is associated with bipolar disorder and subsequently also with schizophrenia. Also, a CACNA1C risk allele has been associated to a disruption in brain connectivity in patients with bipolar disorder, while not or only to a minor degree, in their unaffected relatives or healthy controls.
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective Wikipedia articles.
- ↑ The interactive pathway map can be edited at WikiPathways: "NicotineActivityonChromaffinCells_WP1603"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | Cav1.2
Calcium channel, voltage-dependent, L type, alpha 1C subunit (also known as Cav1.2) is a protein that in humans is encoded by the CACNA1C gene.[1] Cav1.2 is a subunit of L-type voltage-dependent calcium channel.[2]
# Structure and function
This gene encodes an alpha-1 subunit of a voltage-dependent calcium channel. Calcium channels mediate the influx of calcium ions (Ca2+) into the cell upon membrane polarization (see membrane potential and calcium in biology).[3]
The alpha-1 subunit consists of 24 transmembrane segments and forms the pore through which ions pass into the cell. The calcium channel consists of a complex of alpha-1, alpha-2/delta and beta subunits in a 1:1:1 ratio. The S3-S4 linkers of Cav1.2 determine the gating phenotype and modulated gating kinetics of the channel.[4] Cav1.2 is widely expressed in the smooth muscle, pancreatic cells, fibroblasts, and neurons.[5][6] However, it is particularly important and well known for its expression in the heart where it mediates L-type currents, which causes calcium-induced calcium release from the ER Stores via ryanodine receptors. It depolarizes at -30mV and helps define the shape of the action potential in cardiac and smooth muscle.[4] The protein encoded by this gene binds to and is inhibited by dihydropyridine.[7] In the arteries of the brain, high levels of calcium in mitochondria elevates activity of nuclear factor kappa B NF-κB and transcription of CACNA1c and functional Cav1.2 expression increases.[8] Cav1.2 also regulates levels of osteoprotegerin.[9]
CaV1.2 is inhibited by the action of STIM1.[10]
# Regulation
The activity of CaV1.2 channels is tightly regulated by the Ca2+ signals they produce. An increase in intracellular Ca2+ concentration implicated in Cav1.2 facilitation, a form of positive feedback called Ca2+-dependent facilitation, that amplifies Ca2+ influx. In addition, increasing influx intracellular Ca2+ concentration has implicated to exert the opposite effect Ca2+ dependent inactivation.[11] These activation and inactivation mechanisms both involve Ca2+ binding to calmodulin (CaM) in the IQ domain in the C-terminal tail of these channels.[12] Cav1.2 channels are arranged in cluster of eight, on average, in the cell membrane. When calcium ions bind to calmodulin, which in turn binds to a Cav1.2 channel, it allows the Cav1.2 channels within a cluster to interact with each other.[13] This results in channels working cooperatively when they open at the same time to allow more calcium ions to enter and then close together to allow the cell to relax.[13]
# Clinical significance
Mutation in the CACNA1C gene, the single-nucleotide polymorphism located in the third intron of the Cav1.2 gene,[14] are associated with a variant of Long QT syndrome called Timothy's syndrome[15] and also with Brugada syndrome.[16] Large-scale genetic analyses have shown the possibility that CACNA1C is associated with bipolar disorder [17] and subsequently also with schizophrenia.[18][19][20] Also, a CACNA1C risk allele has been associated to a disruption in brain connectivity in patients with bipolar disorder, while not or only to a minor degree, in their unaffected relatives or healthy controls.[21]
# Interactive pathway map
Click on genes, proteins and metabolites below to link to respective Wikipedia articles. [§ 1]
- ↑ The interactive pathway map can be edited at WikiPathways: "NicotineActivityonChromaffinCells_WP1603"..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em} | https://www.wikidoc.org/index.php/Cav1.2 | |
0a2eec26307988b727689945569d0b3a382c630b | wikidoc | Cav1.3 | Cav1.3
Calcium channel, voltage-dependent, L type, alpha 1D subunit (also known as Cav1.3) is a protein that in humans is encoded by the CACNA1D gene. Cav1.3 channels belong to the Cav1 family, which form L-type calcium currents and are sensitive to selective inhibition by dihydropyridines (DHP).
# Structure and function
Voltage-dependent calcium channels (VDCC) are selectively permeable to calcium ions, mediating the movement of these ions in and out of excitable cells. At resting potential, these channels are closed, but when the membrane potential is depolarised these channels open. The influx of calcium ions into the cell can initiate a myriad of calcium-dependent processes including muscle contraction, gene expression, and secretion. Calcium-dependent processes can be halted by lowering intracellular calcium levels, which, for example, can be accomplished by calcium pumps.
Voltage-dependent calcium channels are multi-proteins composed of α1, β, α2δ and γ subunits. The major subunit is α1, which forms the selectivity pore, voltage-sensor and gating apparatus of VDCCs. In Cav1.3 channels, the α1 subunit is α1D. This subunit differentiates Cav1.3 channels from other members of the Cav1 family, such as the predominant and better-studied Cav1.2, which has an α1C subunit. The significance of the α1 subunit also means that it is the primary target for calcium-channel blockers such as dihydropyridines. The remaining β, α2δ and γ subunits have auxiliary functions.
The α1 subunit has four homologous domains, each with six transmembrane segments. Within each homologous domain, the fourth transmembrane segment (S4) is positively charged, as opposed to the other five hydrophobic segments. This characteristic enables S4 to function as the voltage-sensor. Alpha-1D subunits belong to the Cav1 family, which is characterised by L-type calcium currents. Specifically, α1D subunits confer low-voltage activation and slowly inactivating Ca2+ currents, ideal for particular physiological functions such as neurotransmitter release in cochlea inner hair cells.
The biophysical properties of Cav1.3 channels are closely regulated by a C-terminal modulatory domain (CTM), which affects both the voltage dependence of activation and Ca2+ dependent inactivation. Cav1.3 have a low affinity for DHP and activate at sub-threshold membrane potentials, making them ideal for a role in cardiac pacemaking.
# Regulation
## Alternative splicing
Post-transcriptional alternative splicing of Cav1.3 is an extensive and vital regulatory mechanism. Alternative splicing can significantly affect the gating properties of the channel. Comparable to alternative splicing of Cav1.2 transcripts, which confers functional specificity, it has recently been discovered that alternative splicing, particularly in the C-terminus, affects the pharmacological properties of Cav1.3. Strikingly, up to 8-fold differences in dihydropyridine sensitivity between alternatively spliced isoforms have been reported.
## Negative feedback
Cav1.3 channels are regulated by negative feedback to achieve Ca2+ homeostasis. Calcium ions are a critical second messenger, intrinsic to intracellular signal transduction. Extracellular calcium levels are approximated to be 12000-fold greater than intracellular levels. During calcium-dependent processes, the intracellular level of calcium rises by up to 100-fold. It is vitally important to regulate this calcium gradient, not least because high levels of calcium are toxic to the cell, and can induce apoptosis.
Ca2+-bound calmodulin (CaM) interacts with Cav1.3 to induce calcium-dependent inactivation (CDI). Recently, it has been shown that RNA editing of Cav1.3 transcripts is essential for CDI. Contrary to expectation, RNA editing does not simply attenuate the binding of CaM, but weakens the pre-binding of Ca2+-free calmodulin (apoCaM) to channels. The upshot is that CDI is continuously tuneable by changes in levels of CaM.
# Clinical significance
## Hearing
Cav1.3 channels are widely expressed in humans. Notably, their expression predominates cochlea inner hair cells (IHCs). Cav1.3 have been shown through patch clamp experiments to be essential for normal IHC development and synaptic transmission. Therefore, Cav1.3 are required for proper hearing.
## Chromaffin cells
Cav1.3 are densely expressed in chromaffin cells. The low-voltage activation and slow inactivation of these channels makes them ideal for controlling excitability in these cells. Catecholamine secretion from chromaffin cells is particularly sensitive to L-type currents, associated with Cav1.3. Catecholamines have many systemic effects on multiple organs. In addition, L-type channels are responsible for exocytosis in these cells.
## Neurodegeneration
Parkinson's disease is the second most common neurodegenerative disease, in which the death of dopamine-producing cells in the substantia nigra of the midbrain leads to impaired motor function, perhaps best characterised by tremor. Recent evidence suggests that L-type Cav1.3 Ca2+ channels contribute to the death of dopaminergic neurones in patients with Parkinson's disease. The basal activity of these neurones is highly dependent on L-type Ca2+ channels, such as Cav1.3, and it suggested that the pacemaking activity makes the dopaminergic neurones vulnerable to stressors that contribute to their death. Results suggest that inhibition of Cav1.3 is protective against the pathogenesis of Parkinson's.
Inhibition of Cav1.3 can be achieved using calcium channel blockers, such as dihydropyridines (DHPs). These drugs are used since decades to treat arterial hypertension and angina. This is due to their potent vasorelaxant properties, which are mediated by the inhibition of Cav1.2 L-type calcium channels in arterial smooth muscle. Therefore, hypotensive reactions (and leg edema) are regarded dose-limiting side effects when using DHPs for inhibiting Cav1.3 channel in the brain. In the face of this issue, attempts have been made to discover selective Cav1.3 channel blockers. One candidate has been claimed to be a potent and highly selective inhibitor of Cav1.3. This compound, 1-(3-chlorophenethyl)-3-cyclopentylpyrimidine-2,4,6-(1H,3H,5H)-trione was therefore put forward as a candidate for the future treatment of Parkinson's. However, its selectivtiy and potency could not be confirmed in two independent studies from two other groups. One of them even reported gating changes induced by this drug, which indicate channel activating rather than blocking effects
## Prostate cancer
Recent evidence from immunostaining experiments shows that CACNA1D is highly expressed in prostate cancers compared with benign prostate tissues. Blocking L-type channels or knocking down gene expression of CACNA1D significantly suppressed cell-growth in prostate cancer cells. It is important to recognise that this association does not represent a causal link between high levels of α1D protein and prostate cancer. Further investigation is needed to explore the role of CACNA1D gene overexpression in prostate cancer cell growth.
## Aldosteronism
Mutations in the S6 segment of CACNA1D are associated with primary aldosteronism, which causes arterial hypertension. Alterations to the Gly403 residue result in channel activation at less depolarised potentials and impaired channel inactivation. This leads to increased Ca2+ influx, which in turn triggers aldosterone production. | Cav1.3
Calcium channel, voltage-dependent, L type, alpha 1D subunit (also known as Cav1.3) is a protein that in humans is encoded by the CACNA1D gene.[1] Cav1.3 channels belong to the Cav1 family, which form L-type calcium currents and are sensitive to selective inhibition by dihydropyridines (DHP).
# Structure and function
Voltage-dependent calcium channels (VDCC) are selectively permeable to calcium ions, mediating the movement of these ions in and out of excitable cells. At resting potential, these channels are closed, but when the membrane potential is depolarised these channels open. The influx of calcium ions into the cell can initiate a myriad of calcium-dependent processes including muscle contraction, gene expression, and secretion. Calcium-dependent processes can be halted by lowering intracellular calcium levels, which, for example, can be accomplished by calcium pumps.[2]
Voltage-dependent calcium channels are multi-proteins composed of α1, β, α2δ and γ subunits. The major subunit is α1, which forms the selectivity pore, voltage-sensor and gating apparatus of VDCCs. In Cav1.3 channels, the α1 subunit is α1D. This subunit differentiates Cav1.3 channels from other members of the Cav1 family, such as the predominant and better-studied Cav1.2, which has an α1C subunit. The significance of the α1 subunit also means that it is the primary target for calcium-channel blockers such as dihydropyridines. The remaining β, α2δ and γ subunits have auxiliary functions.
The α1 subunit has four homologous domains, each with six transmembrane segments. Within each homologous domain, the fourth transmembrane segment (S4) is positively charged, as opposed to the other five hydrophobic segments. This characteristic enables S4 to function as the voltage-sensor. Alpha-1D subunits belong to the Cav1 family, which is characterised by L-type calcium currents. Specifically, α1D subunits confer low-voltage activation and slowly inactivating Ca2+ currents, ideal for particular physiological functions such as neurotransmitter release in cochlea inner hair cells.
The biophysical properties of Cav1.3 channels are closely regulated by a C-terminal modulatory domain (CTM), which affects both the voltage dependence of activation and Ca2+ dependent inactivation.[3] Cav1.3 have a low affinity for DHP and activate at sub-threshold membrane potentials, making them ideal for a role in cardiac pacemaking.[4]
# Regulation
## Alternative splicing
Post-transcriptional alternative splicing of Cav1.3 is an extensive and vital regulatory mechanism. Alternative splicing can significantly affect the gating properties of the channel. Comparable to alternative splicing of Cav1.2 transcripts, which confers functional specificity,[5] it has recently been discovered that alternative splicing, particularly in the C-terminus, affects the pharmacological properties of Cav1.3. Strikingly, up to 8-fold differences in dihydropyridine sensitivity between alternatively spliced isoforms have been reported.[6]
## Negative feedback
Cav1.3 channels are regulated by negative feedback to achieve Ca2+ homeostasis. Calcium ions are a critical second messenger, intrinsic to intracellular signal transduction. Extracellular calcium levels are approximated to be 12000-fold greater than intracellular levels. During calcium-dependent processes, the intracellular level of calcium rises by up to 100-fold. It is vitally important to regulate this calcium gradient, not least because high levels of calcium are toxic to the cell, and can induce apoptosis.
Ca2+-bound calmodulin (CaM) interacts with Cav1.3 to induce calcium-dependent inactivation (CDI). Recently, it has been shown that RNA editing of Cav1.3 transcripts is essential for CDI.[7] Contrary to expectation, RNA editing does not simply attenuate the binding of CaM, but weakens the pre-binding of Ca2+-free calmodulin (apoCaM) to channels. The upshot is that CDI is continuously tuneable by changes in levels of CaM.
# Clinical significance
## Hearing
Cav1.3 channels are widely expressed in humans. Notably, their expression predominates cochlea inner hair cells (IHCs). Cav1.3 have been shown through patch clamp experiments to be essential for normal IHC development and synaptic transmission.[8] Therefore, Cav1.3 are required for proper hearing.
## Chromaffin cells
Cav1.3 are densely expressed in chromaffin cells. The low-voltage activation and slow inactivation of these channels makes them ideal for controlling excitability in these cells. Catecholamine secretion from chromaffin cells is particularly sensitive to L-type currents, associated with Cav1.3. Catecholamines have many systemic effects on multiple organs. In addition, L-type channels are responsible for exocytosis in these cells.[9]
## Neurodegeneration
Parkinson's disease is the second most common neurodegenerative disease, in which the death of dopamine-producing cells in the substantia nigra of the midbrain leads to impaired motor function, perhaps best characterised by tremor. Recent evidence suggests that L-type Cav1.3 Ca2+ channels contribute to the death of dopaminergic neurones in patients with Parkinson's disease.[4] The basal activity of these neurones is highly dependent on L-type Ca2+ channels, such as Cav1.3, and it suggested that the pacemaking activity makes the dopaminergic neurones vulnerable to stressors that contribute to their death. Results suggest that inhibition of Cav1.3 is protective against the pathogenesis of Parkinson's.[4]
Inhibition of Cav1.3 can be achieved using calcium channel blockers, such as dihydropyridines (DHPs). These drugs are used since decades to treat arterial hypertension and angina. This is due to their potent vasorelaxant properties, which are mediated by the inhibition of Cav1.2 L-type calcium channels in arterial smooth muscle.[10] Therefore, hypotensive reactions (and leg edema) are regarded dose-limiting side effects when using DHPs for inhibiting Cav1.3 channel in the brain.[11] In the face of this issue, attempts have been made to discover selective Cav1.3 channel blockers. One candidate has been claimed to be a potent and highly selective inhibitor of Cav1.3. This compound, 1-(3-chlorophenethyl)-3-cyclopentylpyrimidine-2,4,6-(1H,3H,5H)-trione was therefore put forward as a candidate for the future treatment of Parkinson's.[12] However, its selectivtiy and potency could not be confirmed in two independent studies from two other groups.[13] One of them even reported gating changes induced by this drug, which indicate channel activating rather than blocking effects [14]
## Prostate cancer
Recent evidence from immunostaining experiments shows that CACNA1D is highly expressed in prostate cancers compared with benign prostate tissues. Blocking L-type channels or knocking down gene expression of CACNA1D significantly suppressed cell-growth in prostate cancer cells.[15] It is important to recognise that this association does not represent a causal link between high levels of α1D protein and prostate cancer. Further investigation is needed to explore the role of CACNA1D gene overexpression in prostate cancer cell growth.
## Aldosteronism
Mutations in the S6 segment of CACNA1D are associated with primary aldosteronism, which causes arterial hypertension. Alterations to the Gly403 residue result in channel activation at less depolarised potentials and impaired channel inactivation. This leads to increased Ca2+ influx, which in turn triggers aldosterone production.[16] | https://www.wikidoc.org/index.php/Cav1.3 | |
67e14b75e483f835f01cbd2872740abb2e1ea637 | wikidoc | Cavity | Cavity
# Overview
A cavity is a hole. It may refer to:
- Dental cavity, damage to the structure of teeth
- Resonator, a device designed to select for waves of particular wavelengths
Optical cavity, the cavity resonator of a laser
- Optical cavity, the cavity resonator of a laser
- Cavitation, the phenomenon of partial vacuums forming in fluid, for example, in propellors
- Cavitary pneumonia, a type of pneumonia in which a hole is formed in the lung
de:Kavität
nl:Caviteit
simple:Cavity | Cavity
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
A cavity is a hole. It may refer to:
- Dental cavity, damage to the structure of teeth
- Resonator, a device designed to select for waves of particular wavelengths
Optical cavity, the cavity resonator of a laser
- Optical cavity, the cavity resonator of a laser
- Cavitation, the phenomenon of partial vacuums forming in fluid, for example, in propellors
- Cavitary pneumonia, a type of pneumonia in which a hole is formed in the lung
de:Kavität
nl:Caviteit
simple:Cavity
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Cavities | |
def70f2a61e41a3bf8f7b279fc66fcad3646db8e | wikidoc | Ccdc78 | Ccdc78
Coiled-coil domain-containing 78 (CCDC78) is a protein in humans encoded by the CCDC78 gene. It has several aliases including C16orf25, FLJ34512, CNM4, and JFP10. It is located on the (-) strand on chromosome 16 (16p13.3). Its gene neighborhood includes NARFL (also on the minus strand), HAGHL, FAM173A, and METRN. The CCDC78 gene is 10,892 base pairs long, and the protein contains 438 amino acids. The protein weighs approximately 4.852 KDal. There are several isoforms, including one indicated with a unique congenital myopathy. Several expression profiles show it has ubiquitous expression at moderate levels. Although no paralogs exist several orthologs do.
# Function
The function of this gene is currently unknown. There is evidence that CCDC78 plays a role in skeletal muscle contraction. This is supported by structural similarities to other muscle proteins and by localization assays. CCDC78's predicted structure was similar to that of tropomyosin (see below). The gene product is found primarily in the perinuclear region, the sarcolemmal membrane, and in the reticular pattern of the sarcoplasm. However, localization assays predict it to also be found in the cytoplasm.
# mRNA
General Properties:
- Genomic DNA length: 10,892 bp
- Most common translated mRNA length: 1,317 bp
- 5' Untranslated region: 447 bp
- 3' Untranslated region: 2188 bp
Transcript Variants:
There are 13 known alternative splicing patterns. These can be seen in the adjacent image. One of these is indicated in disease.
# Protein
General Properties:
- Contains two coiled-coil domains
- Molecular Weight: 4.852 KDal
- Isoelectric Point: 8.27
## Expression
When looking at EST profiles in humans, CCDC78 seems to show ubiquitous expression at moderate levels.
Predicted post-translational modification:
Phosphorylation of several serine residues has been predicted by using tools at ExPasy.
## Predicted secondary structure
Secondary structure of CCDC78 was predicted using the protein secondary structure prediction tool PELE. As would be expected with a coiled-coil domain containing protein, there are several α-helices. The model was predicted to be 98% accurate to 65% of the protein. The predicted image can be seen below.
This predicted model is closely related to tropomyosin - a contractile protein.
## Protein-protein interactions
Only one protein has been found to interact with CCDC78. An analysis performed from IntAct showed an interaction between CCDC78 and dAK1_1 in Yersinia pestis.
# Homology
CCDC78 has no known paralogs in the human genome. However, it has several orthologs in other organisms. Orthologs can be found throughout the animal kingdom. CCDC78 is highly conserved in mammals. The coiled-coil domain is highly conserved throughout all orthologs, demonstrating the importance of these domains.
# Clinical relevance
A mutation in this gene has been shown to cause a unique congenital myopathy. This mutation is caused by alternative splicing - a 222 bp in-frame insertion. A group of researchers from the University of Michigan analyzed a family with a dominantly inherited congenital myopathy. After linkage analysis followed by whole-exome capture and next-generation sequencing, they found CCDC78 to be present in affected individuals and absent in >10,000 controls. They then successfully modeled this congenital myopathy in zebrafish. CCDC78 has also been associated with an immune response to Hepatitis B. | Ccdc78
Coiled-coil domain-containing 78 (CCDC78) is a protein in humans encoded by the CCDC78 gene. It has several aliases including C16orf25, FLJ34512, CNM4, and JFP10.[1] It is located on the (-) strand on chromosome 16 (16p13.3). Its gene neighborhood includes NARFL (also on the minus strand), HAGHL, FAM173A, and METRN. The CCDC78 gene is 10,892 base pairs long, and the protein contains 438 amino acids.[2] The protein weighs approximately 4.852 KDal.[3] There are several isoforms, including one indicated with a unique congenital myopathy.[4] Several expression profiles show it has ubiquitous expression at moderate levels. Although no paralogs exist several orthologs do.
# Function
The function of this gene is currently unknown. There is evidence that CCDC78 plays a role in skeletal muscle contraction. This is supported by structural similarities to other muscle proteins and by localization assays. CCDC78's predicted structure was similar to that of tropomyosin (see below).[5] The gene product is found primarily in the perinuclear region, the sarcolemmal membrane, and in the reticular pattern of the sarcoplasm. However, localization assays predict it to also be found in the cytoplasm.[4]
# mRNA
General Properties: [2]
- Genomic DNA length: 10,892 bp
- Most common translated mRNA length: 1,317 bp
- 5' Untranslated region: 447 bp
- 3' Untranslated region: 2188 bp
Transcript Variants:
There are 13 known alternative splicing patterns.[1] These can be seen in the adjacent image. One of these is indicated in disease.[4]
# Protein
General Properties:[3]
- Contains two coiled-coil domains
- Molecular Weight: 4.852 KDal
- Isoelectric Point: 8.27
## Expression
When looking at EST profiles in humans, CCDC78 seems to show ubiquitous expression at moderate levels.[2]
Predicted post-translational modification:
Phosphorylation of several serine residues has been predicted by using tools at ExPasy.[6]
## Predicted secondary structure
Secondary structure of CCDC78 was predicted using the protein secondary structure prediction tool PELE. As would be expected with a coiled-coil domain containing protein, there are several α-helices.[3] The model was predicted to be 98% accurate to 65% of the protein. The predicted image can be seen below.
This predicted model is closely related to tropomyosin - a contractile protein.[5]
## Protein-protein interactions
Only one protein has been found to interact with CCDC78. An analysis performed from IntAct showed an interaction between CCDC78 and dAK1_1 in Yersinia pestis.[7]
# Homology
CCDC78 has no known paralogs in the human genome. However, it has several orthologs in other organisms. Orthologs can be found throughout the animal kingdom. CCDC78 is highly conserved in mammals.[3] The coiled-coil domain is highly conserved throughout all orthologs, demonstrating the importance of these domains.
# Clinical relevance
A mutation in this gene has been shown to cause a unique congenital myopathy.[4] This mutation is caused by alternative splicing - a 222 bp in-frame insertion. A group of researchers from the University of Michigan analyzed a family with a dominantly inherited congenital myopathy. After linkage analysis followed by whole-exome capture and next-generation sequencing, they found CCDC78 to be present in affected individuals and absent in >10,000 controls.[4] They then successfully modeled this congenital myopathy in zebrafish. CCDC78 has also been associated with an immune response to Hepatitis B.[8] | https://www.wikidoc.org/index.php/Ccdc78 | |
2c2f355ab9c9c347b955c7c03dc963780378517d | wikidoc | Celery | Celery
Apium graveolens is plant species in the family Apiaceae, and yields two important vegetables known as celery and celeriac. Cultivars of the species have been used for centuries, whilst others have been domesticated only in the last 200-300 years.
# Common names
- English: celery, leaf celery, stalk celery, celeriac, turnip-rooted celery
- Spanish: apio
- French: céleri, céleri feuille, céleri à couper, céleri-branche, céleri à côtes, céleri-rave
- German: Sellerie
- Italian: Sedano
- Portuguese: aipo, salsão
- Russian: Сельдерей
- Chinese: 芹菜
Pinyin: qín cài
- Pinyin: qín cài
- Persian: کرفس
- Hindi: Radhuni, Ajwain
- Finnish: Selleri
- Norwegian: selleri
- Polish: seler
- Greek: Σέλινο
- Slovene: Zelena
- Swahili: Dania
# Uses
Apium graveolens is used around the world as a vegetable, either for the crisp stems or fleshy taproot.
In temperate countries, celery is also grown for its seeds, which yield a valuable volatile oil used in the perfume and pharmaceutical industries. Celery seeds can be used as flavouring or spice either as whole seeds or, ground and mixed with salt, as celery salt. Celery salt can also be made from an extract of the roots.
It is used as a seasoning, in cocktails (notably to enhance the flavour of Bloody Mary cocktails), on the Chicago-style hot dog, and in Old Bay Seasoning. Celery is one of three vegetables considered the holy trinity (along with onions and bell peppers) of Louisiana Creole and Cajun cuisine. It is also one of the three vegetables (together with onions and carrots) that constitute the French mirepoix, which is often used as a base for sauces and soups.
## Medicine
The use of celery seed in pills for relieving pain was described by Aulus Cornelius Celsus ca. 30 AD.
The whole plant is gently stimulant, nourishing, and restorative; it can be liquidized and the juice taken for joint and urinary tract inflammations, such as rheumatoid arthritis, cystitis or urethritis, for weak conditions and nervous exhaustion.
The seeds, harvested after the plant flowers in its second year, are the basis for a homeopathic extract used as a diuretic. The extract is believed to help clear toxins from the system, so are especially good for gout, where uric acid crystals collect in the joints, and arthritis. They are also used as a mild digestive stimulant. The extract can be combined with almond or sunflower oil, and massaged into arthritic joints or for painful gout in the feet or toes.
The root is an effective diuretic and has been taken for urinary stones and gravel. It also acts as a bitter digestive remedy and liver stimulant. A tincture can be used as a diuretic in hypertension and urinary disorders, as a component in arthritic remedies, or as a kidney energy stimulant and cleanser.
Celery roots, fruits (seeds), and aerial parts, are used ethnomedically to treat mild anxiety and agitation, loss of appetite, fatigue, cough, and as an anthelmintic (vermifuge).
## Caution
- Bergapten in the seeds could increase photosensitivity, so do not apply the essential oil externally in bright sunshine.
- Avoid the oil and large doses of the seeds during pregnancy: they can act as a uterine stimulant.
- Seeds intended for cultivation are not suitable for eating as they are often treated with fungicides.
# Allergic responses
Although many people enjoy foods made with celery, a small minority of people can have severe allergic reactions. For people with celery allergy, exposure can cause potentially fatal anaphylactic shock. The allergen does not appear to be destroyed at cooking temperatures. Celery root - commonly eaten as celeriac, or put into drinks - is known to contain more allergen than the stalk. Seeds contain the highest levels of allergen content. Celery is amongst a small group of foods (headed by peanuts) that appear to provoke the most severe allergic reactions (anaphylaxis). An allergic reaction also may be triggered by eating foods that have been processed with machines that have previously processed celery, making avoiding such foods difficult. In contrast with peanut allergy being most prevalent in the US, celery allergy is most prevalent in Central Europe.
# History
Zohary and Hopf note that celery leaves and inflorences were part of the garlands found in the tomb of Tutankhamun, pharaoh of ancient Egypt, and celery mericarps dated to the 7th century BC were recovered in the Heraion of Samos. However, they note "since A. graveolens grows wild in these areas it is hard to decide whether these remains represent wild or cultivated forms." Only by classical times is it certain that celery was cultivated.
M. Fragiska mentions another archeological find of celery, dating to the 9th century BC, at Kastanas; however, the literary evidence for ancient Greece is far more abundant. In Homer's Iliad, the horses of Myrmidons graze on wild celery that grows in the marshes of Troy, and in Odyssey there is mention of the meadows of violet and wild celery surrounding the cave of Calypso.
A chthonian symbol, celery was said to have sprouted from the blood of Kadmilos, father of the Cabers, chthonian divinities celebrated in Samothrace, Lemnos and Thebes. The spicy odour and dark leaf colour encouraged this association with the cult of death. In classical Greece celery leaves were used as garlands for the dead, and the wreaths of the winners at the Isthmian Games were first made of celery before being replaced by crowns made of pine. According to Pliny the Elder (Natural History XIX.46), in Archaia the garland worn by the winners of the sacred contest at Nemea was also made of celery.
# Cultivation
Apium graveolens grows to 1 m tall. The leaves are pinnate to bipinnate leaves with rhombic leaflets 3-6 cm long and 2-4 cm broad. The flowers are creamy-white, 2-3 mm diameter, produced in dense compound umbels. The seeds are broad ovoid to globose, 1.5-2 mm long and wide.
In North America, commercial production of celery is dominated by a variety called Pascal celery. Gardeners can grow a range of cultivars, many of which differ little from the wild species, mainly in having stouter leaf stems. They are ranged under two classes, white and red; the white cultivars being generally the best flavoured, and the most crisp and tender.
The wild form of celery is known as smallage. It has a furrowed stalk with wedge-shaped leaves, the whole plant having a coarse, rank taste, and a peculiar smell. With cultivation and blanching, the stalks lose their acidic qualities and assume the mild, sweetish, aromatic taste particular to celery as a salad plant.
The plants are raised from seed, sown either in a hot bed or in the open garden according to the season of the year, and after one or two thinnings out and transplantings they are, on attaining a height of 15-20 cm, planted out in deep trenches for convenience of blanching, which is affected by earthing up to exclude light from the stems.
In the past, celery was grown as a vegetable for winter and early spring; because of its antitoxic properties, it was perceived as a cleansing tonic, welcomed after the stagnation of winter.
# Trivia
- Celery contains androsterone, a hormone released through sweat glands said to attract women.
- There is a common belief that celery is so difficult for humans to digest, that it has 'negative calories' because human digestion burns more calories than can be extracted. Snopes believes this to be true, however at only 6kcal per rib, the effect is negligible. Celery is still valuable in diets, where it provides low-calorie fiber bulk.
- The Class B Michigan-Ontario League, a minor league baseball league from the early 20th century, included a team called the Kalamazoo Celery Pickers.
- Dr. Brown's makes a celery-flavoured soft drink called Cel-Ray.
- Some pet rabbits eat a lot of celery. One may wonder if this means rabbits lose a lot of weight. However, a rabbit's natural flora of bacteria in their appendix includes micro-organisms which break down the cellulose in the celery into a form which the rabbit can absorb.
- Exercise-induced anaphylaxis can be exacerbated by eating celery.
- In the British science fiction series Doctor Who, the Fifth Doctor's costume included a piece of celery on the lapel. The reason for this was that he was allergic to certain gases in praxis range of the spectrum and in the presence of these gases, the celery turned purple. In this case, he ate the celery (for if nothing else he was sure it was good for his teeth).
- The closely related Apium bermejoi from the island of Minorca is one of the rarest plants in Europe with only 60 individuals left.
- The edible celery stalk is not a plant stem as often claimed. It is a petiole, which is part of a leaf.
- Foley artists break stalks of celery into a microphone to simulate the sound of breaking bones.
- Celery was banned from the Gillingham's Priestfield Stadium in 1996 after the goalkeeper complained of being struck by celery thrown by spectators.
- Some people report that eating raw celery makes their tongues and mouths numb. (Possible allergic reaction)
- Ancient Greeks once believed that the person who does not like celery also does not enjoy living.
- Fans of Chelsea Football Club have been known to sing a saucy song in which they suggest they might use a "lump of celery" in order to tickle a lady's behind: "Celery, Celery, If she don't come, we'll tickle her bum with a lump of celery"
- In the Nick Jr. and Noggin show The Wonder Pets,when the pets save an animal,they celebrate by eating celery as a congratulations gift.
- In the Honor Harrington book series, the extraterrestrial sentient life forms known as treecats are absolutely addicted to celery.
- There is a small farming community with the name Celeryville outside Willard, Ohio once known for its large yield of celery. | Celery
Template:Nutritionalvalue
Apium graveolens is plant species in the family Apiaceae, and yields two important vegetables known as celery and celeriac. Cultivars of the species have been used for centuries, whilst others have been domesticated only in the last 200-300 years.[1]
# Common names
- English: celery, leaf celery, stalk celery, celeriac, turnip-rooted celery
- Spanish: apio
- French: céleri, céleri feuille, céleri à couper, céleri-branche, céleri à côtes, céleri-rave
- German: Sellerie
- Italian: Sedano
- Portuguese: aipo, salsão
- Russian: Сельдерей
- Chinese: 芹菜
Pinyin: qín cài
- Pinyin: qín cài
- Persian: کرفس
- Hindi: Radhuni, Ajwain
- Finnish: Selleri
- Norwegian: selleri
- Polish: seler
- Greek: Σέλινο
- Slovene: Zelena
- Swahili: Dania
# Uses
Apium graveolens is used around the world as a vegetable, either for the crisp stems or fleshy taproot.
In temperate countries, celery is also grown for its seeds, which yield a valuable volatile oil used in the perfume and pharmaceutical industries. Celery seeds can be used as flavouring or spice either as whole seeds or, ground and mixed with salt, as celery salt. Celery salt can also be made from an extract of the roots.
It is used as a seasoning, in cocktails (notably to enhance the flavour of Bloody Mary cocktails), on the Chicago-style hot dog, and in Old Bay Seasoning. Celery is one of three vegetables considered the holy trinity (along with onions and bell peppers) of Louisiana Creole and Cajun cuisine. It is also one of the three vegetables (together with onions and carrots) that constitute the French mirepoix, which is often used as a base for sauces and soups.
## Medicine
The use of celery seed in pills for relieving pain was described by Aulus Cornelius Celsus ca. 30 AD.[2]
The whole plant is gently stimulant, nourishing, and restorative; it can be liquidized and the juice taken for joint and urinary tract inflammations, such as rheumatoid arthritis, cystitis or urethritis, for weak conditions and nervous exhaustion.[verification needed]
The seeds, harvested after the plant flowers in its second year, are the basis for a homeopathic extract used as a diuretic. The extract is believed to help clear toxins from the system, so are especially good for gout, where uric acid crystals collect in the joints, and arthritis. They are also used as a mild digestive stimulant. The extract can be combined with almond or sunflower oil, and massaged into arthritic joints or for painful gout in the feet or toes.[verification needed]
The root is an effective diuretic and has been taken for urinary stones and gravel. It also acts as a bitter digestive remedy and liver stimulant. A tincture can be used as a diuretic in hypertension and urinary disorders, as a component in arthritic remedies, or as a kidney energy stimulant and cleanser.[verification needed]
Celery roots, fruits (seeds), and aerial parts, are used ethnomedically to treat mild anxiety and agitation, loss of appetite, fatigue, cough, and as an anthelmintic (vermifuge).[verification needed]
## Caution
- Bergapten in the seeds could increase photosensitivity, so do not apply the essential oil externally in bright sunshine.
- Avoid the oil and large doses of the seeds during pregnancy: they can act as a uterine stimulant.
- Seeds intended for cultivation are not suitable for eating as they are often treated with fungicides.
# Allergic responses
Although many people enjoy foods made with celery, a small minority of people can have severe allergic reactions. For people with celery allergy, exposure can cause potentially fatal anaphylactic shock.[3] The allergen does not appear to be destroyed at cooking temperatures. Celery root - commonly eaten as celeriac, or put into drinks - is known to contain more allergen than the stalk. Seeds contain the highest levels of allergen content. Celery is amongst a small group of foods (headed by peanuts) that appear to provoke the most severe allergic reactions (anaphylaxis). An allergic reaction also may be triggered by eating foods that have been processed with machines that have previously processed celery, making avoiding such foods difficult. In contrast with peanut allergy being most prevalent in the US, celery allergy is most prevalent in Central Europe.[4]
# History
Zohary and Hopf note that celery leaves and inflorences were part of the garlands found in the tomb of Tutankhamun, pharaoh of ancient Egypt, and celery mericarps dated to the 7th century BC were recovered in the Heraion of Samos. However, they note "since A. graveolens grows wild in these areas it is hard to decide whether these remains represent wild or cultivated forms." Only by classical times is it certain that celery was cultivated.[5]
M. Fragiska mentions another archeological find of celery, dating to the 9th century BC, at Kastanas; however, the literary evidence for ancient Greece is far more abundant. In Homer's Iliad, the horses of Myrmidons graze on wild celery that grows in the marshes of Troy, and in Odyssey there is mention of the meadows of violet and wild celery surrounding the cave of Calypso.[6]
A chthonian symbol, celery was said to have sprouted from the blood of Kadmilos, father of the Cabers, chthonian divinities celebrated in Samothrace, Lemnos and Thebes. The spicy odour and dark leaf colour encouraged this association with the cult of death. In classical Greece celery leaves were used as garlands for the dead, and the wreaths of the winners at the Isthmian Games were first made of celery before being replaced by crowns made of pine. According to Pliny the Elder (Natural History XIX.46), in Archaia the garland worn by the winners of the sacred contest at Nemea was also made of celery.[6]
# Cultivation
Apium graveolens grows to 1 m tall. The leaves are pinnate to bipinnate leaves with rhombic leaflets 3-6 cm long and 2-4 cm broad. The flowers are creamy-white, 2-3 mm diameter, produced in dense compound umbels. The seeds are broad ovoid to globose, 1.5-2 mm long and wide.
In North America, commercial production of celery is dominated by a variety called Pascal celery. Gardeners can grow a range of cultivars, many of which differ little from the wild species, mainly in having stouter leaf stems. They are ranged under two classes, white and red; the white cultivars being generally the best flavoured, and the most crisp and tender.
The wild form of celery is known as smallage. It has a furrowed stalk with wedge-shaped leaves, the whole plant having a coarse, rank taste, and a peculiar smell. With cultivation and blanching, the stalks lose their acidic qualities and assume the mild, sweetish, aromatic taste particular to celery as a salad plant.
The plants are raised from seed, sown either in a hot bed or in the open garden according to the season of the year, and after one or two thinnings out and transplantings they are, on attaining a height of 15-20 cm, planted out in deep trenches for convenience of blanching, which is affected by earthing up to exclude light from the stems.
In the past, celery was grown as a vegetable for winter and early spring; because of its antitoxic properties, it was perceived as a cleansing tonic, welcomed after the stagnation of winter.
# Trivia
Template:Trivia
- Celery contains androsterone, a hormone released through sweat glands said to attract women.
- There is a common belief that celery is so difficult for humans to digest, that it has 'negative calories' because human digestion burns more calories than can be extracted. Snopes[2] believes this to be true, however at only 6kcal per rib, the effect is negligible. Celery is still valuable in diets, where it provides low-calorie fiber bulk.
- The Class B Michigan-Ontario League, a minor league baseball league from the early 20th century, included a team called the Kalamazoo Celery Pickers.
- Dr. Brown's makes a celery-flavoured soft drink called Cel-Ray.
- Some pet rabbits eat a lot of celery. One may wonder if this means rabbits lose a lot of weight. However, a rabbit's natural flora of bacteria in their appendix includes micro-organisms which break down the cellulose in the celery into a form which the rabbit can absorb.
- Exercise-induced anaphylaxis can be exacerbated by eating celery.
- In the British science fiction series Doctor Who, the Fifth Doctor's costume included a piece of celery on the lapel. The reason for this was that he was allergic to certain gases in praxis range of the spectrum and in the presence of these gases, the celery turned purple. In this case, he ate the celery (for if nothing else he was sure it was good for his teeth).
- The closely related Apium bermejoi from the island of Minorca is one of the rarest plants in Europe with only 60 individuals left.
- The edible celery stalk is not a plant stem as often claimed. It is a petiole, which is part of a leaf.
- Foley artists break stalks of celery into a microphone to simulate the sound of breaking bones.
- Celery was banned from the Gillingham's Priestfield Stadium in 1996 after the goalkeeper complained of being struck by celery thrown by spectators.
- Some people report that eating raw celery makes their tongues and mouths numb. (Possible allergic reaction)
- Ancient Greeks once believed that the person who does not like celery also does not enjoy living.
- Fans of Chelsea Football Club have been known to sing a saucy song in which they suggest they might use a "lump of celery" in order to tickle a lady's behind: "Celery, Celery, If she don't come, we'll tickle her bum with a lump of celery"
- In the Nick Jr. and Noggin show The Wonder Pets,when the pets save an animal,they celebrate by eating celery as a congratulations gift.
- In the Honor Harrington book series, the extraterrestrial sentient life forms known as treecats are absolutely addicted to celery.
- There is a small farming community with the name Celeryville outside Willard, Ohio once known for its large yield of celery. | https://www.wikidoc.org/index.php/Celery | |
651b06d5cbcda651cd612e6aea926b0d8a5a7a18 | wikidoc | Oocyte | Oocyte
# Overview
An oocyte, ovocyte, or rarely oöcyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum. An oocyte is part the ovary development. The germ cells produce a primordial germ cell (PGC) which becomes an oogonia which marks the start of mitosis. After mitosis stops (due to actions of retinoic acid and the mesenephros) meiosis starts. This stage the oogonia is now an Oocyte (pronounced oh'a (like Noah)-site).
# Formation
The formation of an oocyte is called oocytogenesis, which is a part of oogenesis. Oogenesis results in the formation of both primary oocytes before birth, and of secondary oocytes after it as part of ovulation.
# Characteristics
## Cytoplasm
Oocytes are rich in cytoplasm which contains yolk granules to nourish the cell early in development.
## Nucleus
During the primary oocyte stage of oogenesis, the nucleus is called a germinal vesicle
The only normal type of secondary oocyte has sex chromosomes 23,X (where sperm can be 23,X or 23,Y).
## Nest
The space wherein an ovum or immature ovum is located is the cell-nest.
# Abnormalities
- nondisjunction -- a failure of proper homolog separation in meiosis I, or sister chromatid separation in meiosis II can lead to aneuploidy, in which the oocyte has the wrong number of chromosomes, for example 22,X or 24,X. This is the cause of conditions like Down syndrome and Edwards syndrome. It is more likely with advance maternal age.
- Some oocytes have multiple nuclei, although it is thought they never mature. | Oocyte
Template:Infobox Anatomy
# Overview
An oocyte, ovocyte, or rarely oöcyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum. An oocyte is part the ovary development. The germ cells produce a primordial germ cell (PGC) which becomes an oogonia which marks the start of mitosis. After mitosis stops (due to actions of retinoic acid and the mesenephros) meiosis starts. This stage the oogonia is now an Oocyte (pronounced oh'a (like Noah)-site).
# Formation
The formation of an oocyte is called oocytogenesis, which is a part of oogenesis[1]. Oogenesis results in the formation of both primary oocytes before birth, and of secondary oocytes after it as part of ovulation.
# Characteristics
## Cytoplasm
Oocytes are rich in cytoplasm which contains yolk granules to nourish the cell early in development.
## Nucleus
During the primary oocyte stage of oogenesis, the nucleus is called a germinal vesicle[2]
The only normal type of secondary oocyte has sex chromosomes 23,X (where sperm can be 23,X or 23,Y).
## Nest
The space wherein an ovum or immature ovum is located is the cell-nest[3].
# Abnormalities
- nondisjunction -- a failure of proper homolog separation in meiosis I, or sister chromatid separation in meiosis II can lead to aneuploidy, in which the oocyte has the wrong number of chromosomes, for example 22,X or 24,X. This is the cause of conditions like Down syndrome and Edwards syndrome. It is more likely with advance maternal age.
- Some oocytes have multiple nuclei, although it is thought they never mature. | https://www.wikidoc.org/index.php/Cell-nest | |
fd028f8e8fd454ee0fb18309fc256683884a8e1b | wikidoc | Census | Census
A census is the process of obtaining information about every member of a population (not necessarily a human population). The term is mostly used in connection with national 'population and housing censuses' (to be taken every 10 years according to United Nations recommendations); agriculture censuses (all agriculture units) and business censuses (all enterprises).
The census can be contrasted with sampling in which information is only obtained from a subset of a population. As such it is a method used for accumulating statistical data, and also plays a part in democracy (voting). Census data is also commonly used for research, business marketing, planning purposes and not at least as a base for sampling surveys.
It is widely recognized that population and housing censuses are vital for the planning of any society. Traditional censuses are however becoming more and more costly. A rule of thumb for census costs in developing countries have for a long time been 1 USD / enumerated person. More realistic figures today are around 3 USD. These approximates should be taken with great care since a various amount of activities can be included in different countries (e.g. enumerators can either be hired or requested from civil servants). The cost in developed countries is far higher. The cost for the 2000 census in the US is estimated to 4.5 billion USD. Alternative possibilities to retrieve data are investigated. Nordic countries Denmark, Finland and Norway have for several years used administrative registers. Partial censuses ‘Micro censuses’ or ‘Sample censuses' are practiced in France and Germany.
# Census and privacy
While the census provides a useful way of obtaining statistical information about a population, such information can sometimes lead to abuses, political or otherwise, made possible by the linking of individuals' identities to anonymous census data.
It is not unusual for census data to be processed in some way so as to obscure individual information. Some censuses do this by intentionally introducing small statistical errors to prevent the identification of individuals in marginal populations; others swap variables for similar respondents.
Whatever measures have been taken to reduce the privacy risk in census data, new technology in the form of better electronic analysis of data pose increasing challenges to the protection of sensitive individual information.
# Ancient and medieval censuses
The first known census was taken by the Babylonians in 3800 BC, nearly 6000 years ago. Records suggest that it was taken every six or seven years and counted the number of people and livestock, as well as quantities of butter, honey, milk, wool and vegetables.
One of the earliest documented censuses was taken in 500-499 BC by the Persian Empire's military for issuing land grants, and taxation purposes.
Censuses were conducted in the Mauryan Empire as described in Chanakya's (c. 350-283 BC) Arthashastra, which prescribed the collection of population statistics as a measure of state policy for the purpose of taxation. It contains a detailed description of methods of conducting population, economic and agricultural censuses.
The Bible relates stories of several censuses. The Book of Numbers describes a divinely-mandated census that occurred when Moses led the Israelites from Egypt. A later census called by King David of Israel, referred to as the "numbering of the people," incited divine retribution (for being militarily motivated or perhaps displaying lack of faith in God). A Roman census is also mentioned in one of the best-known passages of the Bible in the Gospel of Luke, see Census of Quirinius.
Rome conducted censuses to determine taxes (see Censor). The word 'census' origins in fact from ancient Rome, coming from the Latin word 'censere', meaning ‘estimate’. The Roman census was the most developed of any recorded in the ancient world and it played a crucial role in the administration of the Roman Empire. The Roman census was carried out every five years. It provided a register of citizens and their property from which their duties and privileges could be listed.
The world's oldest extant census data comes from China during the Han Dynasty. Taken in the fall of 2 AD, it is considered by scholars to be quite accurate. At that time there were 59.6 million living in Han China, the world's largest population. The second oldest preserved census is also from the Han, dating back to 140 AD, when only a bit more than 48 million people were recorded. Mass migrations into what is today southern China are believed to be behind this massive demographic decline.
In the Middle Ages, the most famous census in Europe is the Domesday Book, undertaken in 1086 by William I of England so that he could properly tax the land he had recently conquered. In 1183, a census was taken of the crusader Kingdom of Jerusalem, to ascertain the number of men and amount of money that could possibly be raised against an invasion by Saladin, sultan of Egypt and Syria.
A very interesting way to record census information was made in the Inca Empire in the Andean region from the 15th century until the Spaniards conquered their land. The Incas did not have any written language but recorded information collected during censuses and other numeric information as well as non-numeric data on quipus, strings from llama or alpaca hair or cotton cords with numeric and other values encoded by knots in a base 10 positional system.
# Modern censuses
## Afghanistan
A partial and incomplete population census was taken in Afghanistan in 1979. A census is planned for 2007.
## Algeria
Population and housing censuses have been carried out in Algeria in 1967, 1977, 1987 and 1997.
## Antigua & Barbuda
A Population & Housing Census was carried out in 2001
## Argentine
National population census are carried out in Argentina roughly every ten years, the last one being in 2001.
More about census, see: National Institute of Statistics and Census of Argentina
## Austria
The Austrian census is run by the Statistik Austria. It is carried out every ten years, the last on being in 2001.
## Australia
The Australian census is operated by the Australian Bureau of Statistics. It is currently conducted every five years, the last occurrence being on August 8, 2006. Past Australian censuses were conducted in 1911, 1921, 1933, 1947, 1954, 1961, 1966, 1971, 1976, 1981, 1986, 1991, 1996, 2001 and 2006. In 2006, for the first time, Australians were able to complete their census online.
## Bangladesh
Population censuses have been carried out in 1974, 1981, 1991 and 2001. It is done by the Bangladesh Bureau of Statistics (BBS)
## Benin
Population censuses have been taken in Benin in 1978, 1992 and 2002
## Bolivia
Population and housing censuses have been carried out in Bolivia in 1992 and 2001.
## Bosnia-Herzegovina
A census was taken by apostolic vicar the bishop Pavao Dragicevic in 1743.
## Brazil
The Brazilian census is carried out by IBGE, the Brazilian Institute of Geography and Statistics, every 10 years. The last one was in 2000. Earlier censuses were taken in 1872 (the first), 1900, 1920, 1941, 1950, 1960, 1970, 1980 and 1991.
## Bulgaria
The first census was organised after Bulgarian parliament passed a law for national censuses in 1880. A special Act on Statistics was enacted in 1897. It was following on the edge European standards at the time. The area of the next census was widening for the purposes of International Statistical Institute which was planning a world wide census of the then ‘civilized world’ at the time. The Directorate of Statistics was the only institution authorized and responsible with and for organization and of national censuses. The procedure remained the same until WW-II.
During the period in review Bulgaria has organized 16 population censuses (1880, 1884, 1887, 1892, 1900, 1905, 1910, 1920, 1926, 1934, 1946, 1956, 1965, 1975, 1985, 1992 all of them ending in December and 2001 providing data by March same year). Reliability of the statistics, indeed, improved with the time.
The information in the first censuses covers a wide range of data:
- Population statistic – sex, age, nationality, mother tongue, education, religion, different groups of disabled people
- Occupation….
- Animal statistics- providing detailed information on the number of beasts on the village and town level;
- Dwelling statistics – the data is broken down by villages/towns and by type of use – for living and for rent providing purposes
- Vital statistics – marriage, number of family members, age at marriage, mortality and nativity
## Canada
The Canadian census is run by Statistics Canada. The first census conducted in Canada was conducted in 1666, by French intendant Jean Talon, when he took a census to ascertain the number of people living in New France. The individual provinces conducted censuses, in the 19th century and before, sometimes in conjunction with each other. In 1871, Canada's first formal census was conducted, which counted the population of Nova Scotia, Ontario, New Brunswick, and Quebec. In 1918, the Dominion Bureau of Statistics was formed, and replaced by Statistics Canada in 1971.
Censuses in Canada are conducted in five-year intervals. The last two censuses were conducted in 2001 and 2006. Censuses taken in mid-decade (1976, 1986, 1996, etc.) are referred to as quinquennial censuses. Others are referred to as decennial censuses. The first quinquennial census was conducted in 1956.
For the 2006 Census of Canada, respondents were able, for the first time, to choose to complete their census questionnaire online. Other options for answering the questionnaire include postal mail (using a pre-paid envelope) and telephone (using a 800 number).
See also: Canada 2001 Census, Canada 2006 Census.
Alberta
In the Province of Alberta, Section 57 of its Municipal Government Act (MGA) enables municipalities to perform their own censuses on any given year. An official municipal census must be conducted no earlier than April 1 and no later than June 30 of the same year, according to the MGA's Determination of Population Regulation. If municipalities choose to make their census count official, the new population must be submitted to the Ministry of Municipal Affairs and Housing prior to September 1 of the year the census was performed. The latest census counts for Alberta's municipalities are released in the Ministry's annual Official Population List publication.
AltaPop (Alberta Population) is a very useful website that builds upon the data provided by the Province and Statistics Canada. Visit AltaPop to compare municipal and federal census results by municipality, to analyse historic population trends by municipality, and to view detailed annual population summaries either by size of municipality or sorted alphabetically.
## China
Population censuses have been taken in the People's Republic of China in 1953, 1964, 1982, 1990 and 2000. Theses are the world's biggest censuses as they attempt to count every man, woman and child in its colossal population. Some 6 million enumerators were enganged in the 2000 census. An first economic census was taken in 2004.
## Costa Rica
Costa Rica carried out its 9th population census in 2000. INEC, National Institute of Statistics and Census is in charge of conduct these census. Past Costa Rican censuses were conducted in 1864, 1883, 1892, 1927, 1950, 1963, 1973 and 1984.
## Czech Republic
Census in the Czech Republic is carried out every 10 years by the Czech Statistical Office. The last census was taken in 2001.
## Denmark
The first Danish census was in 1700-1701, and contained statistical information about adult men. Only about half of it still exists. A census of school children was taken during the 1730s.
Following these early undertakings, the first census to attempt completely covering all citizens (including women and children who had previously been listed only as numbers) of Denmark-Norway was taken in 1769 . At that point there were 797 584 citizens in the kingdom. Georg Christian Oeder took a statistical census in 1771 which covered Copenhagen, Sjælland, Møn, and Bornholm.
After that, censuses followed somewhat regularly in 1787, 1801, and 1834, and between 1840 and 1860, the censuses were taken every five years, and then every ten years until 1890. Special censuses for Copenhagen were taken in 1885 and 1895.
In the 20th century, censuses were taken every five years from 1901 to 1921, and then every ten years from 1930. The last traditional census was taken in 1970.
A limited population census based on registers was taken in 1976. From 1981 and each year onwards information that corresponds to a population and housing census is retrieved from registers. Denmark was the first country in the world to conduct these censuses from administrative registers. The most important registers are the population register (Det Centrale Personregister), a Building and Dwelling Register and an Enterprise Register. The central statistical office, Statistics Denmark is responsible for compiling these data. This information is available online in the Statbank Denmark.
It is possible to search a portion of the Danish censuses online at Dansk Demografisk Database, and also view scanned versions at Arkivalier Online.
## Egypt
- The Statistical Department of the Ministry of Finance conducted the first census in 1882, which considered as a preparatory step; the first true population census was conducted in 1897. Thereafter, censuses were conducted at ten-year intervals in 1907, 1917, 1927 and so on.
- In 2006 the Central Agency For Public Mobilization and Statistics CAPMAS conducted the thirteenth census in the Egyptian census series where the Egypt's population hit 76.5 million inside and outside the country.
## Ethiopia
Three censuses have been taken in Ethiopia: 1984, 1994 and in 2007. The responsible institution is the Central Statistical Agency.
Most of the census in 2007 was taken in August, while the Somali Region and the Afar Region were not covered. The northern Afar region is a remote, hot and arid area. The eastern Somali region (Ogaden) hosts a large nomadic Somali population and is a conflict area where Ethiopian regular forces are fighting against Ogaden National Liberation Front (ONLF).
## Finland
The first population census was taken in 1749 when Finland was a part of Sweden.
## France
Napoleon Bonaparte began the census in France as a means of determining the number of potential soldiers under his rule. Today, the census in France is carried out by INSEE. Since 2004, a partial census is carried out every year, and the results published as averages over 5 years.
## Germany
The first systematic population on the European continent was taken in 1719 in Prussia (roughly corresponding to today's northern Germany and western Poland).
The first large-scale census in the German Empire took place in 1895. Attempts at introducing a census in West Germany sparked strong popular resentment in the 1980s since many quite personal questions were asked. Some campaigned for a boycott. In the end the Constitutional Court stopped the census in 1980 and 1983. The last census was in 1987. Germany has since used population samples in combination with statistical methods, in place of a full census.
## Greece
Census takes place every 10 years and is carried out by the National Statistical Service of Greece . Last census was in 2001.
## Guatemala
Modern population censuses have been taken in Guatemala in 1930, 1950, 1964, 1973, 1981, 1994 and in 2002. Controversial cenuses were in particular the ones in 1950 and 1964 (misclassification of the Maya population) and the 1994 census (generally questioned).
Relaciones Geográficas of Mexico and Guatemala, 1577-1585.
On May 25, 1577, King Philip II of Spain ordered by royal cédula the preparation of a general description of Spain's holdings in the Indies. Instructions and a questionnaire, issued in 1577 by the Office of the Cronista Mayor-Cosmógrafo, were distributed to local officials in the Viceroyalties of New Spain and Peru to direct the gathering of information. The questionnaire, comprised of fifty items, was designed to elicit basic information about the nature of the land and the life of its peoples. The replies, known as "relaciones geográficas," were written between 1579 and 1585 and were returned to the Cronista Mayor-Cosmógrafo in Spain by the Council of the Indies.
## Hong Kong
Census takes place every 10 years and by-census between two censuses by the Census and Statistics Department of Hong Kong. The last census was conducted in 2001 and the next by-census will take place in 2006.
## Hungary
Official decennial censuses have been taken in Hungary since 1870; the latest one – in line with the recommendations of the United Nations and the Statistical Office of the European Union – was carried out in 2001.
Starting from 1880 the Hungarian census system was based on native language (the language spoken at home in the early life of the person and at the time of the survey), vulgar language (the most frequently used language in the family), and other spoken languages.
## Iceland
The first Icelandic census took place in 1703, following upon the first Danish census of 1700-1701. Further censuses were carried out in 1801, 1845 and 1865. The 1703 exercise was the first ever census to cover all inhabitants of an entire country, mentioning the name, age and social position of each individual. All of the information still exists, although some of the original documents have been lost.
The setting up, in 1952, of the National Register (þjóðskrá) eliminated the need for censuses. All those born in Iceland, and all new residents, are automatically registered. Individuals are identified in the register by means of a national identification number (the so-called kennitala), a number composed of the date of birth in the format ddmmyy and four additional digits, the last of which indicates the century in which the person was born (9 for the 1900s and 0 for the 2000s).
In Iceland, the National Register also doubles as electoral register. Likewise, all bank accounts are linked to the national identification of the owner (companies and institutions all have their own identification numbers).
## India
The decennial census of India is the primary source of information about the demographic characteristics of the population of India which is the second biggest country of the world in terms of population.
The first census in India in modern times is dated 1872. It started as far back as in 1860 and was finished in 1871. Starting from there, a population census has been carried out every 10 years, latest being the fourteenth in February-March 2001.
Census is carried out by the office of the Registrar General and Census Commissioner, India, Delhi under the Census of India Act, 1948. The act gives Central Government many powers like to notify a date for Census, power to ask for the services of any citizen for census work. The law makes it compulsory for every citizen to answer the census questions truthfully. The Act provides penalties for giving false answers or not giving answers at all to the census questionnaire. One of the most important provisions of law is the guarantee for the maintenance of secrecy of the information collected at the census of each individual. The census records are not open to inspection and also not admissible in evidence.
Census happens in two phases, first House Listing and House Numbering Operations and second actual population enumeration phase. Census is carried out by the canvassing method. In this method, each and every household is visited and the information is collected by a specially trained enumerator.
9 February 2001, the first day of the 2001 census was celebrated as the census day.
### Source
- Website of the office of the Registrar General and Census Commissioner, India
- Banthia J.K., Ex Registrar General & Census Commissioner, India. "Mobilising Support for India’s Census - Constraints and Challenges"
## Israel
The first census in Israel was held in November 1948, six months after the creation of the state. Subsequent censuses took place in 1961, 1972, 1983 and 1995. The aforementioned were conducted by the Israel Central Bureau of Statistics.
## Ireland
The census in Ireland is carried out by the Central Statistics Office (Ireland). The previous two censuses were carried out in 2002 and most recently on April 23 2006. The census is carried out every five years, except in 2001, whose census was postponed to 2002 due to the outbreak of foot and mouth disease. According to the 2006 form, "any person who fails or refuses to provide information or who knowingly provides false information may be subject to a fine of up to €25,000," under the Central Statistics Act 1993.
The census in Ireland is very similar to that of the United Kingdom. That is, the "100 year" law applies here as well, as does the recent addition of a question regarding religion to the 2006 census. However, the 1911 Census for the whole of Ireland was made publicly available some time ago.
Since the very first census, the question of "Can you speak Irish?" has been asked. This has often led to misleading figures, as many people know how to speak some Irish through schooling, but do not actually speak it frequently. The 2006 census included how often you spoke the language if you had chosen the "Yes" answer if you spoke Irish.
Also, on the CSO website, instructions for non-English speaking residents of the Republic of Ireland were available. They were mock copies of the census forms, with all headings/questions etc. being translated into a particular language. These were not to be filled out, but were only a guide on how to fill out the English or Irish form.
This census also asked two unique questions relating to ownership of PCs and what Internet connection your home had. The next census will take place in the year 2011.
- Web site of the Central Statistics Office Ireland
## Italy
The census in Italy is carried out by ISTAT every 10 years. The last four were in 1971, 1981, 1991, 2001.
## Japan
Japan collects census information every five years. The figures show the English translation of the 2005 census form. The form solicits information on name, sex, relationship to head of household, year and month of birth, marital status, nationality, number of members of household, type and nature of dwelling, floor area of dwelling, number of hours worked during the week prior to October 1, employment status, name of employer and type of business, and kind of work.
- Explanation of census form, side 1
Explanation of census form, side 1
- Explanation of census form, side 2
Explanation of census form, side 2
## Jordan
The first population census after the independence in 1946 was taken in 1952. It did only count the number of people in the households and could therefore be considered only to be a housing census. The first real complete census was taken in 1961. The following censuses have been taken in 1979, 1994 and 2004. A political sensitive issue have since the Six-Day war in 1967 been the distribution of the population in Palestinians and Jordanians.
## Kenya
Census in Kenya was first held in 1958, when Kenya was still a Colony administrated by the British. Since 1969 census has been taken every ten years. The last census to date was in 1999.
## Kosovo
Kosovo is formally a part of Serbia but is administrated by the UN since 1999. A population census is planned under international supervision for 2007.
## Latvia
The most recent census in Latvia was in 2000. Before that, it was about 6 censuses, most part of these previous censuses was in the USSR time. The census in Latvia is carried out by Centrālā Statistikas Pārvalde (Central Statistical Bureau).
## Lebanon
Any census has not been taken in Lebanon since 1932.
## Macedonia
The foundation of the Republic of Macedonia followed the break up of the former Yugoslav Republic in 1991. The first population and housing census was taken in the summer 1994. The second census was taken in the autumn 2002. Both censuses were observed by international experts due to the sensitive issue regarding the ethnic distribution (Macedonian vs Albanian population).
## Mozambique
The first census was taken in 1980. The second in 1997. The third was taken 1-14 August 2007.
## Netherlands
The first census in the Netherlands was conducted in 1795, and the last in 1971. A law was produced on April 22 1879, saying that a census be conducted every ten years.
The census that was supposed to be conducted in 1981 was postponed and later cancelled. A call for privacy was responsible for the cancellation of any further census since 1991.
## New Zealand
The census in New Zealand is carried out by Statistics New Zealand (Tatauranga Aotearoa), every five years. The last was on 7 March 2006. For the 2006 Census of New Zealand, respondents could choose to complete their census questionnaire online. See New Zealand Census of Population and Dwellings.
## Nigeria
Population censuses have been taken in Nigeria during colonial time in 1866, 1871, 1896, 1901, 1911, 1921 and 1952. The censuses covered only the southern part of the country except for the 1952 census which was country wide. It shall be noted that the censuses before 1921 were merely based on administrative estimates than on an actual enumeration.
Censuses during the independence were taken 1963, 1973, 1991 and 2006. The results from 1973 were highly disputed. The preliminary results for 2006 indicates a population of 140,000,000. 700,000 enumerators were engaged in this operation.
## Norway
The two first male census was conducted during the 1660s and 1701. Later statistical censuses were held in 1769, 1815, 1835, 1845, and 1855. Norway’s first nominative, complete census was taken in 1801, when Norway still was ruled by the Oldenburg dynasty of Denmark-Norway. The scope of the census followed the de jure principle, so military persons should be included as well as foreigners if they were residents. The 1865, 1875 and 1900 censuses are digitized, and are made searchable on the internet. The census records are made public available when 100 years have passed. Since 1900, the census has been conducted every ten years. (However, the 1940 census was postponed to 1946.) Since 2001 the population census has been combined with the housing statistics.
## Oman
Censuses have been taken in the Sultanate of Oman in 1993 and 2003.
## Peru
The first census in Peru was carried out in 1836. The tenth and last one was the 2005 Census and was carried out by Instituto Nacional de Estadística e Informática. The next census will be the 2007 Census.
## Poland
The census in Poland is carried out by GUS every circa 10 years - see censuses in Poland. The last one occurred in 2002.
## Portugal
The first census in Portugal was carried out in 1864. The census in Portugal is carried out by INE every 10 years. The last one occurred in 2001.
## Romania
The first census in Romania was carried out in 1859. Nowadays it is carried every ten years by the Institutul Naţional de Statistică (INSSE). The last one occurred in 2002.
## Russia/USSR
In Russia, the first (and the only) Russian Empire Census was carried out in 1897. All-Union Population Censuses were carried out in the USSR (which included RSFSR and the other republics) in 1920 (urban only), 1926, 1937, 1939, 1959, 1970, 1979, and 1989. The first post-Soviet Russian Census was carried out in 2002. The next census is tentatively planned for 2010. Currently, the census is the responsibility of the Federal State Statistics Service.
## Saudi Arabia
Population censuses have been taken in Saudi Arabia in 1962/63 (incomplete), 1974 (complete but not reliable), 1992 and 2004. An agriculture census was taken in 1999.
## Serbia
The census takes place every 10 years. The last census was in 2002.
## Slovenia
The first census of modern Slovenia was carried in 1991, after independence had been declared. The Statistical Office of the Republic of Slovenia (Statistični urad Republike Slovenije) conducted the second census in 2002. Further censuses are planned for every 10 years.
## South Africa
The first census of South Africa was taken in 1911. Several enumerations have occurred since then, with the most recent two being carried out by Statistics South Africa in 1996 and 2001.
## Spain
The census in Spain is carried out by INE every 10 years. The first modern census was carried out in 1768 by Conde de Aranda, under the reign of Carlos III. The last four were in 1971, 1981, 1991, 2001.
## Sudan
Population censuses have been carried out in Sudan in 1955/56, 1973 (national), 1983 (national) and 1993 (only north). A census is planned for February 2008.
## Sweden
The first population census in Sweden was carried out in 1749. The last population and housing census was carried out in 1990. It is planned to conduct population and housing censuses based on registers in the future.
## Switzerland
In Switzerland, the Federal Population Census (Template:Lang-de, Template:Lang-fr) has been carried out every 10 years starting in 1850. The census was initiated by Federal Councillor Stefano Franscini, who evaluated the data of the first census all by himself after Parliament failed to provide the necessary funds. The census is now being conducted by the Swiss Federal Statistical Office, which makes most results available on its website.
Data being collected include population data (citizenship, place of residence, place of birth, position in household, number of children, religion, languages, education, profession, place of work, etc.), household data (number of individuals living in the household, etc.), accommodation data (surface area, amount of rent paid, etc.) and building data (geocoordinates, time of construction, number of floors, etc.). Participation is compulsory and reached 99.87% of the population in 2000.
Starting in 2010, the census will cease to be conducted through written questionnaires distributed nationwide. Instead, data in existing population registers will be used. That data will be supplemented with a biannual questionnaire sample of 200,000 people as well as regular microcensuses.
## Syria
The first population census in Syria was taken by the French Mandatory Regime in 1921-22. This is however not considered reliable. Censuses during independence have been taken 1947, 1960 (the first comprehensive demographic investigation), 1970, 1976 (a sample census), 1981, 1994 and 2004.
## Turkey
The Turkish census is run by Devlet İstatistik Enstitüsü. The first census in Turkey was conducted in 1927. After 1935, it took place in every 5 years until 1990. Now, the census takes place every 10 years. The last census was in 2000. It can be noted that the census enumeration takes place on one single day in Turkey (in other countries it takes 1-2 weeks). This required some 900,000 enumerators in 2000. The 15th census based on improved geographical information systems is planned for 2010.
A census was taken in the Ottoman Empire 1831-38 by Sultan Mahmud II (1808-1839) as a part of the reform movement Tazimat. Even Christian and Jewish men were counted but no women..
## Uganda
The first censuses in Uganda were taken 1911, 1921 and 1931. It was done in a rather primitive way. Enumeration unit was 'huts' and not individuals.
More scientific censuses were taken 1948 and 1959 where the enumeration unit was persons. The census was however divided into two separate enumerations, one for Africans, and one for the non-African population.
The censuses during independence 1969, 1980, 1991 were taken jointly for all races. The censuses 1980 and 1991 included housing information and in addition a larger questionnaire for a sample of the population. It can be mentioned that the questionnaires for the 1980 were lost and only provisional figures are available from this census.
The census in 2002 involved some 50,000 enumerators and supervisors.
## Ukraine
The first post-Soviet Ukrainian Census was carried out by State Statistics Committee of Ukraine in 2001, twelve years after the last All-Union census in 1989.
## United Kingdom
In the 7th century, Dál Riata (now western Scotland and northern County Antrim in Ireland) was the first territory in what is now the UK to conduct a census, with what was called the "Tradition of the Men of Alba" (Senchus fer n-Alban). England took its first Census when the Domesday Book was compiled in 1086 for tax purposes.
Following the influence of Malthus and concerns stemming from his An Essay On The Principle Of Population the UK census as we know it today started in 1801. This was championed by John Rickman who managed the first four up to 1831, partly to ascertain the number of men able to fight in the Napoleonic wars. Rickman's 12 reasons - set out in 1798 and repeated in Parliamentary debates - for conducting a UK census included the following justifications:
- 'the intimate knowledge of any country must form the rational basis of legislation and diplomacy'
- 'an industrious population is the basic power and resource of any nation, and therefore its size needs to be known'
- 'the number of men who were required for conscription to the militia in different areas should reflect the area's population'
- 'there were defence reasons for wanting to know the number of seamen'
- 'the need to plan the production of corn and thus to know the number of people who had to be fed'
- 'a census would indicate the Government's intention to promote the public good' and
- 'the life insurance industry would be stimulated by the results.'
The census has been conducted every ten years since 1801 and most recently in 2001. The first four censuses (1801-1831) were mainly statistical (that is, they were mainly headcounts and contained virtually no personal information).
The 1841 Census, conducted by the General Register Office, was the first to record the names of everyone in a household or institution. However, their relationship to the head of the household wasn’t noted, although sometimes this can be inferred from the occupation shown (eg servant). Those under the age of 15 had their proper ages listed, but for those who were older the ages were supposed to be rounded down to the nearest five years, although this rule was not strictly adhered to. Precise birthplaces were not given - at best the birthplace can be narrowed down to the county in which the person was living.
From 1851 onwards the census shows the exact age and relationship to the head of household for each individual; the place of birth was also listed, but with varying degrees of precision. Sometimes those who were born abroad have the annotation B.S. or British Subject.
The censuses are reasonably accurate. However, ages in particular are frequently shown incorrectly, though often the difference is only one year; in general the younger the individual the more accurate the age shown. Birthplaces often vary from one census to the next: a common error is to show the place where the census was taken as the birthplace, but most of the variations in birthplace can be accounted for by changes in geographical scale (for example, the nearest town being shown instead of the precise village, or a city being shown instead of the relevant suburb).
The censuses are also remarkably complete - though inevitably a small percentage of the population wasn’t recorded for one reason or another, and in some cases the records are missing or damaged (notably in 1861). Furthermore, all censuses of Ireland before 1901 have been lost or destroyed.
Because of World War II, there was no census in 1941. However, following the passage into law (on 5 September 1939) of the National Registration Act a population count was carried out on 29 September 1939, which was, in effect, a census.
The census is undertaken for the government by the Office for National Statistics (ONS) for policy and planning purposes, and statistical information is also made available in published reports and on the ONS's website. Public access to the census returns is restricted under the terms of the 100-year rule and the most recent returns made available to researchers are those of the 1901 Census.
The 2001 census was the first year in which the government asked about religion. Perhaps encouraged by a hoax chain letter that started in New Zealand, 390,000 people entered their religion as Jedi Knight (more than either Sikhs, Buddhists or Jews), with some areas registering up to 2.6% of people as "Jedi". It was wrongly implied in emails that stating "Jedi" on the form would cause it to become an "official religion". No such thing exists in the United Kingdom. However, the director of reporting and analysis at the ONS stated that it may have helped with the collection process as it encouraged young people, who are often missed, to complete forms. (See Jedi census phenomenon.)
All of the British censuses from 1841-1901 have been transcribed and indexed and are available online; there is a joint project between the National Archives of Ireland and Library and Archives Canada to digitize the 1901 and 1911 censuses for the whole of Ireland, and it is possible this will be completed by the end of 2007.
## United States
The United States Constitution mandates that the census be taken at least once every 10 years, and that the number of members of the United States House of Representatives from each state be determined accordingly. In addition, census statistics are used for apportioning Federal funding for many social and economic programs.
The first U.S. Census was conducted in 1790 by Federal marshals. Census-takers went door-to-door and recorded the number of people in each household, along with the name of the head of the household. Slaves were enumerated, but for apportionment purposes each counted as only three-fifths of a citizen. American Indians being neither taxed nor considered during apportionment were not counted in the census. The first census counted 3.9 million people, less than half the population of New York City in 2000; the 2000 census counted over 281 million people. In 1902, Congress established the Census Bureau as a permanent Federal agency.
In recent times, there were two forms of questionnaire – long and short. The Long Form and its additional questions about items such as daily commute times, housing unit factors, etc. has been replaced by the American Community Survey (ACS). Computer algorithms (based on complex sampling rules) determined which form was mailed to a given household (in practice, of those households whose locations are on the Census Master Address List), one in six receiving the long form. This was supplemented by census workers going door-to-door to talk to people who failed to return the forms. In addition to a simple count of residents, the Census Bureau collects a variety of statistics, on topics ranging from ethnicity to the presence of indoor plumbing. While some critics claim that census questions are an invasion of privacy, the data collected by every question is either required to enforce some federal law (such as the Voting Rights Act) or is required to administer some federal program. The United States Congress gives approval to every question asked on the Census.
Despite a massive effort, the Census Bureau has never been able to count every individual, leading to controversy about whether to use statistical methods to supplement the numbers for some purposes, as well as arguments over how to improve the actual head count. The Supreme Court has ruled that only an actual head count can be used to apportion Congressional seats; however, cities and minority representatives have complained that urban residents and minorities are undercounted. In several cases, the Census Bureau will recount an area with disputed figures, provided the local government pays for the time and effort. The State of Utah protested the figures of the 2000 decennial census because it stood to gain a seat in the House of Representatives, but North Carolina gained it instead. Had the Census Bureau been mandated to count the numbers of Utahns living overseas, including many Mormon missionaries, Utah might have gained the seat.
To minimize the burden on individuals and to provide improved data, the Bureau is preparing several alternative methods for gathering economic, demographic, and social information, including the American Community Survey and record linking of depersonalized administrative records with other administrative records and Census Bureau surveys.
By law (92 Stat. 915, Public Law 95-416, enacted on October 5 1978), census records are sealed for 72 years. This figure has remained unchanged since prior to the updates of the 1978 law, reflecting an era when life expectancy was under 60 years, and thus attempts to protect individual's privacy by prohibiting the release of such information during their expected lifetimes. Thus, the most recent Census released to the public was the 1930 Census, released in 2002.
Indexes to some of the U.S. Censuses have been produced over the years, making the process of searching old census records much easier. Some indexes of census records have been produced by amateur volunteer genealogists. Due to the sheer volume of information, and the manual methodologies involved, the indexing used to be limited to the head-of-household. These indexes were published in bound volumes and are often available in regional libraries along with microfilm rolls that can be researched.
While valuable, indexes produced from these censuses can be problematic to use. The original census records from this era were completed by hand by census enumerators; this leads to problems in handwriting recognition and variations in spelling of surnames within the original documents.
The 1880 to 1920 censuses have indexes of last names, produced using the Soundex system; the indexing project was performed by the Works Progress Administration. The Soundex system is tolerant of variations in spelling; names with similar sounds but different spellings have the same encoding. The chief motivation in producing the Soundex name indexes was to assist citizens in finding census records to provide evidence of age, especially for those born before the advent of governmentally-approved birth certificates. (Verification of age was needed to establish eligibility for old-age benefits such as Social Security). Partial Soundex indexes of the 1930 census are available; resources from the Works Progress Administration were diverted towards support of World War II efforts before the project was completed.
With the advent of computers, and more recently, the Internet, expanded indexes including all family members are beginning to appear on genealogy websites. These are accompanied with hypertext links that take the researcher directly to an image of the original census page, without having to travel to a regional library and scroll through endless rolls of microfilm. (see or or / for examples)
Genealogists view censuses as secondary sources of information; primary sources of information such as birth certificates and even obituaries are viewed as more reliable. Still, census information often provides useful information for genealogists and clues on where to proceed to find further primary source documents.
Researchers must use care when working with census records. Census taker handwriting varies from excellent to illegible. Information may also be inaccurate due to spelling variants by the recorder. Some information, especially ages, may be incorrect due to vanity or confusion on the part of the information giver. Birthplaces may not be accurate depending on which family member gave the information. With these and other cautions in mind, census records can be very informative and useful.
### Local
In additional to the decennial federal census, more localized versions are often used. An example of this is Massachusetts, which takes a statewide census every fifth year. Likewise, each community in Massachusetts takes a municipal census each year. Some states conducted limited censuses for various purposes which predate the 1790 federal census schedules. Various state archives can usually direct the researcher to these sources.
# Notes
- ↑ The Census and Privacy
- ↑ Kuhrt, A. (1995) The Ancient Near East c. 3000–330BC Vol 2 Routledge, London. pp 695
- ↑ History of Indian Census
- ↑ H. Yoon (1985). "An early Chinese idea of a dynamic environmental cycle", GeoJournal 10 (2), p. 211-212.
- ↑ Central Bureaus of Statistics (Kenya): Census cartography: The Kenyan Experience
- ↑ History of the Federal Population Census, Swiss Federal Statistical Office, accessed October 2007
- ↑ Overview of the Federal Population Census, Swiss Federal Statistical Office, accessed October 2007 | Census
A census is the process of obtaining information about every member of a population (not necessarily a human population). The term is mostly used in connection with national 'population and housing censuses' (to be taken every 10 years according to United Nations recommendations); agriculture censuses (all agriculture units) and business censuses (all enterprises).
The census can be contrasted with sampling in which information is only obtained from a subset of a population. As such it is a method used for accumulating statistical data, and also plays a part in democracy (voting). Census data is also commonly used for research, business marketing, planning purposes and not at least as a base for sampling surveys.
It is widely recognized that population and housing censuses are vital for the planning of any society. Traditional censuses are however becoming more and more costly. A rule of thumb for census costs in developing countries have for a long time been 1 USD / enumerated person. More realistic figures today are around 3 USD. These approximates should be taken with great care since a various amount of activities can be included in different countries (e.g. enumerators can either be hired or requested from civil servants). The cost in developed countries is far higher. The cost for the 2000 census in the US is estimated to 4.5 billion USD. Alternative possibilities to retrieve data are investigated. Nordic countries Denmark, Finland and Norway have for several years used administrative registers. Partial censuses ‘Micro censuses’ or ‘Sample censuses' are practiced in France and Germany.
# Census and privacy
While the census provides a useful way of obtaining statistical information about a population, such information can sometimes lead to abuses, political or otherwise, made possible by the linking of individuals' identities to anonymous census data.[1]
It is not unusual for census data to be processed in some way so as to obscure individual information. Some censuses do this by intentionally introducing small statistical errors to prevent the identification of individuals in marginal populations; others swap variables for similar respondents.
Whatever measures have been taken to reduce the privacy risk in census data, new technology in the form of better electronic analysis of data pose increasing challenges to the protection of sensitive individual information.
# Ancient and medieval censuses
The first known census was taken by the Babylonians in 3800 BC, nearly 6000 years ago. Records suggest that it was taken every six or seven years and counted the number of people and livestock, as well as quantities of butter, honey, milk, wool and vegetables.
One of the earliest documented censuses was taken in 500-499 BC by the Persian Empire's military for issuing land grants, and taxation purposes.[2]
Censuses were conducted in the Mauryan Empire as described in Chanakya's (c. 350-283 BC) Arthashastra, which prescribed the collection of population statistics as a measure of state policy for the purpose of taxation. It contains a detailed description of methods of conducting population, economic and agricultural censuses.[3]
The Bible relates stories of several censuses. The Book of Numbers describes a divinely-mandated census that occurred when Moses led the Israelites from Egypt. A later census called by King David of Israel, referred to as the "numbering of the people," incited divine retribution (for being militarily motivated or perhaps displaying lack of faith in God). A Roman census is also mentioned in one of the best-known passages of the Bible in the Gospel of Luke, see Census of Quirinius.
Rome conducted censuses to determine taxes (see Censor). The word 'census' origins in fact from ancient Rome, coming from the Latin word 'censere', meaning ‘estimate’. The Roman census was the most developed of any recorded in the ancient world and it played a crucial role in the administration of the Roman Empire. The Roman census was carried out every five years. It provided a register of citizens and their property from which their duties and privileges could be listed.
The world's oldest extant census data comes from China during the Han Dynasty[citation needed]. Taken in the fall of 2 AD, it is considered by scholars to be quite accurate[citation needed]. At that time there were 59.6 million living in Han China, the world's largest population.[4] The second oldest preserved census is also from the Han, dating back to 140 AD, when only a bit more than 48 million people were recorded. Mass migrations into what is today southern China are believed to be behind this massive demographic decline.
In the Middle Ages, the most famous census in Europe is the Domesday Book, undertaken in 1086 by William I of England so that he could properly tax the land he had recently conquered. In 1183, a census was taken of the crusader Kingdom of Jerusalem, to ascertain the number of men and amount of money that could possibly be raised against an invasion by Saladin, sultan of Egypt and Syria.
A very interesting way to record census information was made in the Inca Empire in the Andean region from the 15th century until the Spaniards conquered their land. The Incas did not have any written language but recorded information collected during censuses and other numeric information as well as non-numeric data on quipus, strings from llama or alpaca hair or cotton cords with numeric and other values encoded by knots in a base 10 positional system.
# Modern censuses
## Afghanistan
A partial and incomplete population census was taken in Afghanistan in 1979. A census is planned for 2007.
## Algeria
Population and housing censuses have been carried out in Algeria in 1967, 1977, 1987 and 1997.
## Antigua & Barbuda
A Population & Housing Census was carried out in 2001
## Argentine
National population census are carried out in Argentina roughly every ten years, the last one being in 2001.
More about census, see: National Institute of Statistics and Census of Argentina
## Austria
The Austrian census is run by the Statistik Austria. It is carried out every ten years, the last on being in 2001.
## Australia
The Australian census is operated by the Australian Bureau of Statistics. It is currently conducted every five years, the last occurrence being on August 8, 2006. Past Australian censuses were conducted in 1911, 1921, 1933, 1947, 1954, 1961, 1966, 1971, 1976, 1981, 1986, 1991, 1996, 2001 and 2006. In 2006, for the first time, Australians were able to complete their census online.
## Bangladesh
Population censuses have been carried out in 1974, 1981, 1991 and 2001. It is done by the Bangladesh Bureau of Statistics (BBS)
## Benin
Population censuses have been taken in Benin in 1978, 1992 and 2002
## Bolivia
Population and housing censuses have been carried out in Bolivia in 1992 and 2001.
## Bosnia-Herzegovina
A census was taken by apostolic vicar the bishop Pavao Dragicevic in 1743.
## Brazil
The Brazilian census is carried out by IBGE, the Brazilian Institute of Geography and Statistics, every 10 years. The last one was in 2000. Earlier censuses were taken in 1872 (the first), 1900, 1920, 1941, 1950, 1960, 1970, 1980 and 1991.
## Bulgaria
The first census was organised after Bulgarian parliament passed a law for national censuses in 1880. A special Act on Statistics was enacted in 1897. It was following on the edge European standards at the time. The area of the next census was widening for the purposes of International Statistical Institute which was planning a world wide census of the then ‘civilized world’ at the time. The Directorate of Statistics was the only institution authorized and responsible with and for organization and of national censuses. The procedure remained the same until WW-II.
During the period in review Bulgaria has organized 16 population censuses (1880, 1884, 1887, 1892, 1900, 1905, 1910, 1920, 1926, 1934, 1946, 1956, 1965, 1975, 1985, 1992 all of them ending in December and 2001 providing data by March same year). Reliability of the statistics, indeed, improved with the time.
The information in the first censuses covers a wide range of data:
• Population statistic – sex, age, nationality, mother tongue, education, religion, different groups of disabled people
• Occupation….
• Animal statistics- providing detailed information on the number of beasts on the village and town level;
• Dwelling statistics – the data is broken down by villages/towns and by type of use – for living and for rent providing purposes
• Vital statistics – marriage, number of family members, age at marriage, mortality and nativity
## Canada
The Canadian census is run by Statistics Canada. The first census conducted in Canada was conducted in 1666, by French intendant Jean Talon, when he took a census to ascertain the number of people living in New France. The individual provinces conducted censuses, in the 19th century and before, sometimes in conjunction with each other. In 1871, Canada's first formal census was conducted, which counted the population of Nova Scotia, Ontario, New Brunswick, and Quebec. In 1918, the Dominion Bureau of Statistics was formed, and replaced by Statistics Canada in 1971.
Censuses in Canada are conducted in five-year intervals. The last two censuses were conducted in 2001 and 2006. Censuses taken in mid-decade (1976, 1986, 1996, etc.) are referred to as quinquennial censuses. Others are referred to as decennial censuses. The first quinquennial census was conducted in 1956.
For the 2006 Census of Canada, respondents were able, for the first time, to choose to complete their census questionnaire online. Other options for answering the questionnaire include postal mail (using a pre-paid envelope) and telephone (using a 800 number).
See also: Canada 2001 Census, Canada 2006 Census.
Alberta
In the Province of Alberta, Section 57 of its Municipal Government Act (MGA) enables municipalities to perform their own censuses on any given year. An official municipal census must be conducted no earlier than April 1 and no later than June 30 of the same year, according to the MGA's Determination of Population Regulation. If municipalities choose to make their census count official, the new population must be submitted to the Ministry of Municipal Affairs and Housing prior to September 1 of the year the census was performed. The latest census counts for Alberta's municipalities are released in the Ministry's annual Official Population List publication.
AltaPop (Alberta Population) is a very useful website that builds upon the data provided by the Province and Statistics Canada. Visit AltaPop to compare municipal and federal census results by municipality, to analyse historic population trends by municipality, and to view detailed annual population summaries either by size of municipality or sorted alphabetically.
## China
Population censuses have been taken in the People's Republic of China in 1953, 1964, 1982, 1990 and 2000. Theses are the world's biggest censuses as they attempt to count every man, woman and child in its colossal population. Some 6 million enumerators were enganged in the 2000 census. An first economic census was taken in 2004.
## Costa Rica
Costa Rica carried out its 9th population census in 2000. INEC, National Institute of Statistics and Census is in charge of conduct these census. Past Costa Rican censuses were conducted in 1864, 1883, 1892, 1927, 1950, 1963, 1973 and 1984.
## Czech Republic
Census in the Czech Republic is carried out every 10 years by the Czech Statistical Office. The last census was taken in 2001.
## Denmark
The first Danish census was in 1700-1701, and contained statistical information about adult men. Only about half of it still exists. A census of school children was taken during the 1730s.
Following these early undertakings, the first census to attempt completely covering all citizens (including women and children who had previously been listed only as numbers) of Denmark-Norway was taken in 1769 [1]. At that point there were 797 584 citizens in the kingdom. Georg Christian Oeder took a statistical census in 1771 which covered Copenhagen, Sjælland, Møn, and Bornholm.
After that, censuses followed somewhat regularly in 1787, 1801, and 1834, and between 1840 and 1860, the censuses were taken every five years, and then every ten years until 1890. Special censuses for Copenhagen were taken in 1885 and 1895.
In the 20th century, censuses were taken every five years from 1901 to 1921, and then every ten years from 1930. The last traditional census was taken in 1970.
A limited population census based on registers was taken in 1976. From 1981 and each year onwards information that corresponds to a population and housing census is retrieved from registers. Denmark was the first country in the world to conduct these censuses from administrative registers. The most important registers are the population register (Det Centrale Personregister), a Building and Dwelling Register and an Enterprise Register. The central statistical office, Statistics Denmark is responsible for compiling these data. This information is available online in the Statbank Denmark.
It is possible to search a portion of the Danish censuses online at Dansk Demografisk Database, and also view scanned versions at Arkivalier Online.
## Egypt
- The Statistical Department of the Ministry of Finance conducted the first census in 1882, which considered as a preparatory step; the first true population census was conducted in 1897. Thereafter, censuses were conducted at ten-year intervals in 1907, 1917, 1927 and so on.
- In 2006 the Central Agency For Public Mobilization and Statistics CAPMAS conducted the thirteenth census in the Egyptian census series where the Egypt's population hit 76.5 million inside and outside the country.[2]
## Ethiopia
Three censuses have been taken in Ethiopia: 1984, 1994 and in 2007. The responsible institution is the Central Statistical Agency.
Most of the census in 2007 was taken in August, while the Somali Region and the Afar Region were not covered. The northern Afar region is a remote, hot and arid area. The eastern Somali region (Ogaden) hosts a large nomadic Somali population and is a conflict area where Ethiopian regular forces are fighting against Ogaden National Liberation Front (ONLF).
## Finland
The first population census was taken in 1749 when Finland was a part of Sweden.
## France
Napoleon Bonaparte began the census in France as a means of determining the number of potential soldiers under his rule. Today, the census in France is carried out by INSEE. Since 2004, a partial census is carried out every year, and the results published as averages over 5 years.
## Germany
The first systematic population on the European continent was taken in 1719 in Prussia (roughly corresponding to today's northern Germany and western Poland).
The first large-scale census in the German Empire took place in 1895. Attempts at introducing a census in West Germany sparked strong popular resentment in the 1980s since many quite personal questions were asked. Some campaigned for a boycott. In the end the Constitutional Court stopped the census in 1980 and 1983. The last census was in 1987. Germany has since used population samples in combination with statistical methods, in place of a full census.
## Greece
Census takes place every 10 years and is carried out by the National Statistical Service of Greece [3]. Last census was in 2001.
## Guatemala
Modern population censuses have been taken in Guatemala in 1930, 1950, 1964, 1973, 1981, 1994 and in 2002. Controversial cenuses were in particular the ones in 1950 and 1964 (misclassification of the Maya population) and the 1994 census (generally questioned).
Relaciones Geográficas of Mexico and Guatemala, 1577-1585.
On May 25, 1577, King Philip II of Spain ordered by royal cédula the preparation of a general description of Spain's holdings in the Indies. Instructions and a questionnaire, issued in 1577 by the Office of the Cronista Mayor-Cosmógrafo, were distributed to local officials in the Viceroyalties of New Spain and Peru to direct the gathering of information. The questionnaire, comprised of fifty items, was designed to elicit basic information about the nature of the land and the life of its peoples. The replies, known as "relaciones geográficas," were written between 1579 and 1585 and were returned to the Cronista Mayor-Cosmógrafo in Spain by the Council of the Indies.
## Hong Kong
Census takes place every 10 years and by-census between two censuses by the Census and Statistics Department of Hong Kong. The last census was conducted in 2001 and the next by-census will take place in 2006.
## Hungary
Official decennial censuses have been taken in Hungary since 1870; the latest one – in line with the recommendations of the United Nations and the Statistical Office of the European Union – was carried out in 2001.
Starting from 1880 the Hungarian census system was based on native language (the language spoken at home in the early life of the person and at the time of the survey), vulgar language (the most frequently used language in the family), and other spoken languages.
## Iceland
The first Icelandic census took place in 1703, following upon the first Danish census of 1700-1701. Further censuses were carried out in 1801, 1845 and 1865. The 1703 exercise was the first ever census to cover all inhabitants of an entire country, mentioning the name, age and social position of each individual. All of the information still exists, although some of the original documents have been lost.
The setting up, in 1952, of the National Register (þjóðskrá) eliminated the need for censuses. All those born in Iceland, and all new residents, are automatically registered. Individuals are identified in the register by means of a national identification number (the so-called kennitala), a number composed of the date of birth in the format ddmmyy and four additional digits, the last of which indicates the century in which the person was born (9 for the 1900s and 0 for the 2000s).
In Iceland, the National Register also doubles as electoral register. Likewise, all bank accounts are linked to the national identification of the owner (companies and institutions all have their own identification numbers).
## India
The decennial census of India is the primary source of information about the demographic characteristics of the population of India which is the second biggest country of the world in terms of population.
The first census in India in modern times is dated 1872. It started as far back as in 1860 and was finished in 1871. Starting from there, a population census has been carried out every 10 years, latest being the fourteenth in February-March 2001.
Census is carried out by the office of the Registrar General and Census Commissioner, India, Delhi under the Census of India Act, 1948. The act gives Central Government many powers like to notify a date for Census, power to ask for the services of any citizen for census work. The law makes it compulsory for every citizen to answer the census questions truthfully. The Act provides penalties for giving false answers or not giving answers at all to the census questionnaire. One of the most important provisions of law is the guarantee for the maintenance of secrecy of the information collected at the census of each individual. The census records are not open to inspection and also not admissible in evidence.
Census happens in two phases, first House Listing and House Numbering Operations and second actual population enumeration phase. Census is carried out by the canvassing method. In this method, each and every household is visited and the information is collected by a specially trained enumerator.
9 February 2001, the first day of the 2001 census was celebrated as the census day.
### Source
- Website of the office of the Registrar General and Census Commissioner, India
- Banthia J.K., Ex Registrar General & Census Commissioner, India. "Mobilising Support for India’s Census - Constraints and Challenges"
## Israel
The first census in Israel was held in November 1948, six months after the creation of the state. Subsequent censuses took place in 1961, 1972, 1983 and 1995. The aforementioned were conducted by the Israel Central Bureau of Statistics.
## Ireland
The census in Ireland is carried out by the Central Statistics Office (Ireland). The previous two censuses were carried out in 2002 and most recently on April 23 2006. The census is carried out every five years, except in 2001, whose census was postponed to 2002 due to the outbreak of foot and mouth disease. According to the 2006 form, "any person who fails or refuses to provide information or who knowingly provides false information may be subject to a fine of up to €25,000," under the Central Statistics Act 1993.
The census in Ireland is very similar to that of the United Kingdom. That is, the "100 year" law applies here as well, as does the recent addition of a question regarding religion to the 2006 census. However, the 1911 Census for the whole of Ireland was made publicly available some time ago.
Since the very first census, the question of "Can you speak Irish?" has been asked. This has often led to misleading figures, as many people know how to speak some Irish through schooling, but do not actually speak it frequently. The 2006 census included how often you spoke the language if you had chosen the "Yes" answer if you spoke Irish.
Also, on the CSO website, instructions for non-English speaking residents of the Republic of Ireland were available. They were mock copies of the census forms, with all headings/questions etc. being translated into a particular language. These were not to be filled out, but were only a guide on how to fill out the English or Irish form.
This census also asked two unique questions relating to ownership of PCs and what Internet connection your home had. The next census will take place in the year 2011.
- Web site of the Central Statistics Office Ireland
## Italy
The census in Italy is carried out by ISTAT every 10 years. The last four were in 1971, 1981, 1991, 2001.
## Japan
Japan collects census information every five years. The figures show the English translation of the 2005 census form. The form solicits information on name, sex, relationship to head of household, year and month of birth, marital status, nationality, number of members of household, type and nature of dwelling, floor area of dwelling, number of hours worked during the week prior to October 1, employment status, name of employer and type of business, and kind of work.
- Explanation of census form, side 1
Explanation of census form, side 1
- Explanation of census form, side 2
Explanation of census form, side 2
## Jordan
The first population census after the independence in 1946 was taken in 1952. It did only count the number of people in the households and could therefore be considered only to be a housing census. The first real complete census was taken in 1961. The following censuses have been taken in 1979, 1994 and 2004. A political sensitive issue have since the Six-Day war in 1967 been the distribution of the population in Palestinians and Jordanians.
## Kenya
Census in Kenya was first held in 1958, when Kenya was still a Colony administrated by the British. Since 1969 census has been taken every ten years. The last census to date was in 1999.[5]
## Kosovo
Kosovo is formally a part of Serbia but is administrated by the UN since 1999. A population census is planned under international supervision for 2007.
## Latvia
The most recent census in Latvia was in 2000. Before that, it was about 6 censuses, most part of these previous censuses was in the USSR time. The census in Latvia is carried out by Centrālā Statistikas Pārvalde (Central Statistical Bureau).
## Lebanon
Any census has not been taken in Lebanon since 1932.
## Macedonia
The foundation of the Republic of Macedonia followed the break up of the former Yugoslav Republic in 1991. The first population and housing census was taken in the summer 1994. The second census was taken in the autumn 2002. Both censuses were observed by international experts due to the sensitive issue regarding the ethnic distribution (Macedonian vs Albanian population).
## Mozambique
The first census was taken in 1980. The second in 1997. The third was taken 1-14 August 2007.
## Netherlands
The first census in the Netherlands was conducted in 1795, and the last in 1971. A law was produced on April 22 1879, saying that a census be conducted every ten years.
The census that was supposed to be conducted in 1981 was postponed and later cancelled. A call for privacy was responsible for the cancellation of any further census since 1991.
## New Zealand
The census in New Zealand is carried out by Statistics New Zealand (Tatauranga Aotearoa), every five years. The last was on 7 March 2006. For the 2006 Census of New Zealand, respondents could choose to complete their census questionnaire online. See New Zealand Census of Population and Dwellings.
## Nigeria
Population censuses have been taken in Nigeria during colonial time in 1866, 1871, 1896, 1901, 1911, 1921 and 1952. The censuses covered only the southern part of the country except for the 1952 census which was country wide. It shall be noted that the censuses before 1921 were merely based on administrative estimates than on an actual enumeration.
Censuses during the independence were taken 1963, 1973, 1991 and 2006. The results from 1973 were highly disputed. The preliminary results for 2006 indicates a population of 140,000,000. 700,000 enumerators were engaged in this operation.
## Norway
The two first male census was conducted during the 1660s and 1701. Later statistical censuses were held in 1769, 1815, 1835, 1845, and 1855. Norway’s first nominative, complete census was taken in 1801, when Norway still was ruled by the Oldenburg dynasty of Denmark-Norway. The scope of the census followed the de jure principle, so military persons should be included as well as foreigners if they were residents. The 1865, 1875 and 1900 censuses are digitized, and are made searchable on the internet. The census records are made public available when 100 years have passed. Since 1900, the census has been conducted every ten years. (However, the 1940 census was postponed to 1946.) Since 2001 the population census has been combined with the housing statistics.
## Oman
Censuses have been taken in the Sultanate of Oman in 1993 and 2003.
## Peru
The first census in Peru was carried out in 1836. The tenth and last one was the 2005 Census and was carried out by Instituto Nacional de Estadística e Informática. The next census will be the 2007 Census.
## Poland
The census in Poland is carried out by GUS every circa 10 years - see censuses in Poland. The last one occurred in 2002.
## Portugal
The first census in Portugal was carried out in 1864. The census in Portugal is carried out by INE every 10 years. The last one occurred in 2001.
## Romania
The first census in Romania was carried out in 1859. Nowadays it is carried every ten years by the Institutul Naţional de Statistică (INSSE). The last one occurred in 2002.
## Russia/USSR
In Russia, the first (and the only) Russian Empire Census was carried out in 1897. All-Union Population Censuses were carried out in the USSR (which included RSFSR and the other republics) in 1920 (urban only), 1926, 1937, 1939, 1959, 1970, 1979, and 1989. The first post-Soviet Russian Census was carried out in 2002. The next census is tentatively planned for 2010. Currently, the census is the responsibility of the Federal State Statistics Service.
## Saudi Arabia
Population censuses have been taken in Saudi Arabia in 1962/63 (incomplete), 1974 (complete but not reliable), 1992 and 2004. An agriculture census was taken in 1999.
## Serbia
The census takes place every 10 years. The last census was in 2002.
## Slovenia
The first census of modern Slovenia was carried in 1991, after independence had been declared. The Statistical Office of the Republic of Slovenia (Statistični urad Republike Slovenije) conducted the second census in 2002. Further censuses are planned for every 10 years.
## South Africa
The first census of South Africa was taken in 1911. Several enumerations have occurred since then[4], with the most recent two being carried out by Statistics South Africa in 1996 and 2001.
## Spain
The census in Spain is carried out by INE every 10 years. The first modern census was carried out in 1768 by Conde de Aranda, under the reign of Carlos III. The last four were in 1971, 1981, 1991, 2001.
## Sudan
Population censuses have been carried out in Sudan in 1955/56, 1973 (national), 1983 (national) and 1993 (only north). A census is planned for February 2008.
## Sweden
The first population census in Sweden was carried out in 1749. The last population and housing census was carried out in 1990. It is planned to conduct population and housing censuses based on registers in the future.
## Switzerland
In Switzerland, the Federal Population Census (Template:Lang-de, Template:Lang-fr) has been carried out every 10 years starting in 1850. The census was initiated by Federal Councillor Stefano Franscini, who evaluated the data of the first census all by himself after Parliament failed to provide the necessary funds.[6] The census is now being conducted by the Swiss Federal Statistical Office, which makes most results available on its website.
Data being collected include population data (citizenship, place of residence, place of birth, position in household, number of children, religion, languages, education, profession, place of work, etc.), household data (number of individuals living in the household, etc.), accommodation data (surface area, amount of rent paid, etc.) and building data (geocoordinates, time of construction, number of floors, etc.). Participation is compulsory and reached 99.87% of the population in 2000.[7]
Starting in 2010, the census will cease to be conducted through written questionnaires distributed nationwide. Instead, data in existing population registers will be used. That data will be supplemented with a biannual questionnaire sample of 200,000 people as well as regular microcensuses.
## Syria
The first population census in Syria was taken by the French Mandatory Regime in 1921-22. This is however not considered reliable. Censuses during independence have been taken 1947, 1960 (the first comprehensive demographic investigation), 1970, 1976 (a sample census), 1981, 1994 and 2004.
## Turkey
The Turkish census is run by Devlet İstatistik Enstitüsü. The first census in Turkey was conducted in 1927. After 1935, it took place in every 5 years until 1990. Now, the census takes place every 10 years. The last census was in 2000. It can be noted that the census enumeration takes place on one single day in Turkey (in other countries it takes 1-2 weeks). This required some 900,000 enumerators in 2000. The 15th census based on improved geographical information systems is planned for 2010.
A census was taken in the Ottoman Empire 1831-38 by Sultan Mahmud II (1808-1839) as a part of the reform movement Tazimat. Even Christian and Jewish men were counted but no women..
## Uganda
The first censuses in Uganda were taken 1911, 1921 and 1931. It was done in a rather primitive way. Enumeration unit was 'huts' and not individuals.
More scientific censuses were taken 1948 and 1959 where the enumeration unit was persons. The census was however divided into two separate enumerations, one for Africans, and one for the non-African population.
The censuses during independence 1969, 1980, 1991 were taken jointly for all races. The censuses 1980 and 1991 included housing information and in addition a larger questionnaire for a sample of the population. It can be mentioned that the questionnaires for the 1980 were lost and only provisional figures are available from this census.
The census in 2002 involved some 50,000 enumerators and supervisors.
## Ukraine
The first post-Soviet Ukrainian Census was carried out by State Statistics Committee of Ukraine in 2001, twelve years after the last All-Union census in 1989.
## United Kingdom
Template:Subsections
In the 7th century, Dál Riata (now western Scotland and northern County Antrim in Ireland) was the first territory in what is now the UK to conduct a census, with what was called the "Tradition of the Men of Alba" (Senchus fer n-Alban). England took its first Census when the Domesday Book was compiled in 1086 for tax purposes.
Following the influence of Malthus and concerns stemming from his An Essay On The Principle Of Population the UK census as we know it today started in 1801. This was championed by John Rickman who managed the first four up to 1831, partly to ascertain the number of men able to fight in the Napoleonic wars. Rickman's 12 reasons - set out in 1798 and repeated in Parliamentary debates - for conducting a UK census included the following justifications:
- 'the intimate knowledge of any country must form the rational basis of legislation and diplomacy'
- 'an industrious population is the basic power and resource of any nation, and therefore its size needs to be known'
- 'the number of men who were required for conscription to the militia in different areas should reflect the area's population'
- 'there were defence reasons for wanting to know the number of seamen'
- 'the need to plan the production of corn and thus to know the number of people who had to be fed'
- 'a census would indicate the Government's intention to promote the public good' and
- 'the life insurance industry would be stimulated by the results.'
The census has been conducted every ten years since 1801 and most recently in 2001. The first four censuses (1801-1831) were mainly statistical (that is, they were mainly headcounts and contained virtually no personal information).
The 1841 Census, conducted by the General Register Office, was the first to record the names of everyone in a household or institution. However, their relationship to the head of the household wasn’t noted, although sometimes this can be inferred from the occupation shown (eg servant). Those under the age of 15 had their proper ages listed, but for those who were older the ages were supposed to be rounded down to the nearest five years, although this rule was not strictly adhered to. Precise birthplaces were not given - at best the birthplace can be narrowed down to the county in which the person was living.
From 1851 onwards the census shows the exact age and relationship to the head of household for each individual; the place of birth was also listed, but with varying degrees of precision. Sometimes those who were born abroad have the annotation B.S. or British Subject.
The censuses are reasonably accurate. However, ages in particular are frequently shown incorrectly, though often the difference is only one year; in general the younger the individual the more accurate the age shown. Birthplaces often vary from one census to the next: a common error is to show the place where the census was taken as the birthplace, but most of the variations in birthplace can be accounted for by changes in geographical scale (for example, the nearest town being shown instead of the precise village, or a city being shown instead of the relevant suburb).
The censuses are also remarkably complete - though inevitably a small percentage of the population wasn’t recorded for one reason or another, and in some cases the records are missing or damaged (notably in 1861). Furthermore, all censuses of Ireland before 1901 have been lost or destroyed.
Because of World War II, there was no census in 1941. However, following the passage into law (on 5 September 1939) of the National Registration Act a population count was carried out on 29 September 1939, which was, in effect, a census.
The census is undertaken for the government by the Office for National Statistics (ONS) for policy and planning purposes, and statistical information is also made available in published reports and on the ONS's website. Public access to the census returns is restricted under the terms of the 100-year rule and the most recent returns made available to researchers are those of the 1901 Census.
The 2001 census was the first year in which the government asked about religion. Perhaps encouraged by a hoax chain letter that started in New Zealand, 390,000 people entered their religion as Jedi Knight (more than either Sikhs, Buddhists or Jews), with some areas registering up to 2.6% of people as "Jedi". It was wrongly implied in emails that stating "Jedi" on the form would cause it to become an "official religion". No such thing exists in the United Kingdom. However, the director of reporting and analysis at the ONS stated that it may have helped with the collection process as it encouraged young people, who are often missed, to complete forms. (See Jedi census phenomenon.)
All of the British censuses from 1841-1901 have been transcribed and indexed and are available online; there is a joint project between the National Archives of Ireland and Library and Archives Canada to digitize the 1901 and 1911 censuses for the whole of Ireland, and it is possible this will be completed by the end of 2007.
## United States
The United States Constitution mandates that the census be taken at least once every 10 years, and that the number of members of the United States House of Representatives from each state be determined accordingly. In addition, census statistics are used for apportioning Federal funding for many social and economic programs.
The first U.S. Census was conducted in 1790 by Federal marshals. Census-takers went door-to-door and recorded the number of people in each household, along with the name of the head of the household. Slaves were enumerated, but for apportionment purposes each counted as only three-fifths of a citizen. American Indians being neither taxed nor considered during apportionment were not counted in the census. The first census counted 3.9 million people, less than half the population of New York City in 2000; the 2000 census counted over 281 million people. In 1902, Congress established the Census Bureau as a permanent Federal agency.
In recent times, there were two forms of questionnaire – long and short. The Long Form and its additional questions about items such as daily commute times, housing unit factors, etc. has been replaced by the American Community Survey (ACS). Computer algorithms (based on complex sampling rules) determined which form was mailed to a given household (in practice, of those households whose locations are on the Census Master Address List), one in six receiving the long form. This was supplemented by census workers going door-to-door to talk to people who failed to return the forms. In addition to a simple count of residents, the Census Bureau collects a variety of statistics, on topics ranging from ethnicity to the presence of indoor plumbing. While some critics claim that census questions are an invasion of privacy, the data collected by every question is either required to enforce some federal law (such as the Voting Rights Act) or is required to administer some federal program. The United States Congress gives approval to every question asked on the Census.
Despite a massive effort, the Census Bureau has never been able to count every individual, leading to controversy about whether to use statistical methods to supplement the numbers for some purposes, as well as arguments over how to improve the actual head count. The Supreme Court has ruled that only an actual head count can be used to apportion Congressional seats; however, cities and minority representatives have complained that urban residents and minorities are undercounted. In several cases, the Census Bureau will recount an area with disputed figures, provided the local government pays for the time and effort. The State of Utah protested the figures of the 2000 decennial census because it stood to gain a seat in the House of Representatives, but North Carolina gained it instead. Had the Census Bureau been mandated to count the numbers of Utahns living overseas, including many Mormon missionaries, Utah might have gained the seat.
To minimize the burden on individuals and to provide improved data, the Bureau is preparing several alternative methods for gathering economic, demographic, and social information, including the American Community Survey and record linking of depersonalized administrative records with other administrative records and Census Bureau surveys.
By law (92 Stat. 915, Public Law 95-416, enacted on October 5 1978), census records are sealed for 72 years. This figure has remained unchanged since prior to the updates of the 1978 law, reflecting an era when life expectancy was under 60 years, and thus attempts to protect individual's privacy by prohibiting the release of such information during their expected lifetimes. Thus, the most recent Census released to the public was the 1930 Census, released in 2002.
Indexes to some of the U.S. Censuses have been produced over the years, making the process of searching old census records much easier. Some indexes of census records have been produced by amateur volunteer genealogists. Due to the sheer volume of information, and the manual methodologies involved, the indexing used to be limited to the head-of-household. These indexes were published in bound volumes and are often available in regional libraries along with microfilm rolls that can be researched.
While valuable, indexes produced from these censuses can be problematic to use. The original census records from this era were completed by hand by census enumerators; this leads to problems in handwriting recognition and variations in spelling of surnames within the original documents.
The 1880 to 1920 censuses have indexes of last names, produced using the Soundex system; the indexing project was performed by the Works Progress Administration. The Soundex system is tolerant of variations in spelling; names with similar sounds but different spellings have the same encoding. The chief motivation in producing the Soundex name indexes was to assist citizens in finding census records to provide evidence of age, especially for those born before the advent of governmentally-approved birth certificates. (Verification of age was needed to establish eligibility for old-age benefits such as Social Security). Partial Soundex indexes of the 1930 census are available; resources from the Works Progress Administration were diverted towards support of World War II efforts before the project was completed.
With the advent of computers, and more recently, the Internet, expanded indexes including all family members are beginning to appear on genealogy websites. These are accompanied with hypertext links that take the researcher directly to an image of the original census page, without having to travel to a regional library and scroll through endless rolls of microfilm. (see http://www.familysearch.org or http://www.ancestry.com or http://www.census-online.com/links/ for examples)
Genealogists view censuses as secondary sources of information; primary sources of information such as birth certificates and even obituaries are viewed as more reliable. Still, census information often provides useful information for genealogists and clues on where to proceed to find further primary source documents.
Researchers must use care when working with census records. Census taker handwriting varies from excellent to illegible. Information may also be inaccurate due to spelling variants by the recorder. Some information, especially ages, may be incorrect due to vanity or confusion on the part of the information giver. Birthplaces may not be accurate depending on which family member gave the information. With these and other cautions in mind, census records can be very informative and useful.
### Local
In additional to the decennial federal census, more localized versions are often used. An example of this is Massachusetts, which takes a statewide census every fifth year. Likewise, each community in Massachusetts takes a municipal census each year. Some states conducted limited censuses for various purposes which predate the 1790 federal census schedules. Various state archives can usually direct the researcher to these sources.
# Notes
- ↑ The Census and Privacy
- ↑ Kuhrt, A. (1995) The Ancient Near East c. 3000–330BC Vol 2 Routledge, London. pp 695
- ↑ History of Indian Census
- ↑ H. Yoon (1985). "An early Chinese idea of a dynamic environmental cycle", GeoJournal 10 (2), p. 211-212.
- ↑ Central Bureaus of Statistics (Kenya): Census cartography: The Kenyan Experience
- ↑ History of the Federal Population Census, Swiss Federal Statistical Office, accessed October 2007
- ↑ Overview of the Federal Population Census, Swiss Federal Statistical Office, accessed October 2007 | https://www.wikidoc.org/index.php/Census | |
9679dfcd70b6f9ac508d377f84f48dc5cc41cf2b | wikidoc | Earwax | Earwax
Synonyms and keywords: Cerumen
# Overview
Earwax, also known by the medical term cerumen, is a yellowish, waxy substance secreted in the ear canal of humans and many other mammals. It plays an important role in the human ear canal, assisting in cleaning and lubrication, and also provides some protection from bacteria, fungi, and insects. Excess or impacted cerumen can press against the eardrum and/or occlude the external auditory canal and impair hearing.
# Production, Composition, and Different Types
Cerumen is produced in the outer third of the cartilaginous portion of the human ear canal. It is a mixture of viscous secretions from sebaceous glands and less-viscous ones from modified apocrine sweat glands. The primary components of earwax are the final products in the HMG-CoA reductase pathway, namely, squalene, lanosterol, and cholesterol.
There are two distinct genetically determined types of earwax: the wet type, which is dominant, and the dry type, which is recessive. Asians and Native Americans are more likely to have the dry type of cerumen (grey and flaky), whereas Caucasians and Africans are more likely to have the wet type (honey-brown to dark-brown and moist). Cerumen type has been used by anthropologists to track human migratory patterns, such as those of the Inuit.
The difference in cerumen type has been tracked to a single base change (a single nucleotide polymorphism) in a gene known as "ATP-binding cassette C11 gene". In addition to affecting cerumen type, this mutation also reduces sweat production. The researchers conjecture that the reduction in sweat was beneficial to the ancestors of East Asians and Native Americans who are thought to have lived in cold climates.
# Function
## Cleaning
Cleaning of the ear canal occurs as a result of the "conveyor belt" process of epithelial migration, aided by jaw movement. Cells formed in the centre of the tympanic membrane migrate outwards from the umbo (at a rate equivalent to that of fingernail growth) to the walls of the ear canal, and accelerate towards the entrance of the ear canal. The cerumen in the canal is also carried outwards, taking with it any dirt, dust, and particulate matter that may have gathered in the canal. Jaw movement assists this process by dislodging debris attached to the walls of the ear canal, increasing the likelihood of its expulsion.
## Lubrication
Lubrication prevents desiccation, itching, and burning of the skin within the ear canal (known as asteatosis). The lubricative properties arise from the high lipid content of the sebum produced by the sebaceous glands. In wet-type cerumen at least, these lipids include cholesterol, squalene, and many long-chain fatty acids and alcohols.
## Antibacterial and Antifungal Roles
While studies conducted up until the 1960s found little evidence supporting an antibacterial role for cerumen, more recent studies have found that cerumen has a bactericidal effect on some strains of bacteria. Cerumen has been found to be effective in reducing the viability of a wide range of bacteria (sometimes by up to 99%), including Haemophilus influenzae, Staphylococcus aureus, and many variants of Escherichia coli. The growth of two fungi commonly present in otomycosis was also significantly inhibited by human cerumen. These antimicrobial properties are due principally to the presence of saturated fatty acids, lysozyme and, especially, to the relatively low pH of cerumen (typically around 6.1 in normal individuals).
# Removal
Excessive cerumen may impede the passage of sound in the ear canal, causing conductive hearing loss. It is also estimated to be the cause of 60–80% of hearing aid faults. As mentioned above, movement of the jaw helps the ears' natural cleaning process, so chewing gum and talking can both help. If this is insufficient, the most common method of cerumen removal by general practitioners is syringing with warm water (used by 95% of GPs). A curette method is more likely to be used by otolaryngologists when the ear canal is partially occluded and the material is not adhering to the skin of the ear canal.
## Cerumenolysis
In cases of those who have the "wet-type" of earwax, it is usually necessary to soften wax before its removal. This process is referred to as cerumenolysis, and is achieved using a solution known as a cerumenolytic agent which is introduced into the ear canal. The most common home-remedy for this purpose is olive oil. Other commercially available and common cerumenolytics include:
- Carbamide peroxide (6.5%) and glycerine
- Sodium bicarbonate B.P.C. (sodium bicarbonate and glycerine)
- Various organic liquids (glycerol, almond oil, mineral oil, baby oil)
- Cerumol (arachis oil, turpentine and dichlorobenzene)
- Cerumenex (Triethanolamine, polypeptides and oleate-condensate)
- Exterol, Otex (UK brand name) (urea, hydrogen peroxide and glycerine)
- Docusate, a detergent,an active ingredient found in laxatives
A cerumenolytic should be used 2-3 times daily for 3-5 days prior to the cerumen extraction. Although most commercially available cerumenolytics available in the U.S. are identical, containing carbamide peroxide (6.5%) and glycerine, a 10% solution of sodium bicarbonate (baking soda) was found to be a more effective cerumenolytic than several commercially-available solutions (Cerumenex, Auralgan) and numerous organic liquids, including glycerine, olive oil, and alcohol. Additionally, 1 mL of docusate was also found to be a more effective cerumenolytic than several commercially-available solutions (Cerumenex, Debrox) . Docusate may be extracted from liquid preparations of laxatives, such as Colace.
A systematic review of studies of the effectiveness of topical preparations for the treatment of earwax concluded that cerumenolysis is better than no treatment, but there is little to choose between oil- and water-based preparations (including plain water). Applying such a preparation half an hour before syringing is probably as effective as applying it for several days. Several days' treatment with some preparations not based on water or oil appears promising. More studies are needed.
## Syringing
Once the cerumen has been softened, it may be removed from the ear canal by irrigation. Ear syringing techniques are described in great detail by Wilson & Roeser, and Blake et al., who advise pulling the external ear up and back, and aiming the nozzle of the syringe slightly upwards and backwards so that the water flows as a cascade along the roof of the canal. The irrigation solution flows out of the canal along its floor, taking wax and debris with it. The solution used to irrigate the ear canal is usually warm water, normal saline, sodium bicarbonate solution, or a solution of water and vinegar to help prevent secondary infection.
Patients generally prefer the irrigation solution to be warmed to body temperature, as dizziness is a common side effect of syringing with fluids that are colder or warmer than body temperature. Sharp et al. recommend 37 °C, while Blake et al. recommend using water at 38 °C, one degree above body temperature, and stress that this should be checked with a thermometer.
A syringe should be used to gently stream water into the ear. For children the rate and speed should be lower. After irrigating, tip the head to allow the water to drain. Irrigation may need to be repeated several times. If the water stream hurts then the flow should be slower. It is better to irrigate too gently for a long period than irrigate too forcefully attempting to remove wax quickly. This procedure can be done at home in the shower using a self-use ear irrigation syringe with a right angle tip. After the wax is removed, the ear can be dried tipping the head then gently pulling the ear upwards to straighten the ear canal. If this does not remove enough water, the ear can be dried with a hair dryer set on low.
## Curette Method
The earwax is removed through the use of an ear pick, which physically dislodges the earwax and scoops it out of the ear canal. In the west, use of a curette or ear pick is often only done in the hands of health professionals; a modified curette having a safety stop to prevent deep insertion for self-use is available. Curetting earwax using an ear pick is common in East Asia. As the earwax of most East Asians is of the dry type, it is extremely easy to remove all earwax via light scraping with an ear pick as it simply falls out in large pieces or dry flakes, often on it's own.
## Hazards
A postal survey of British general practitioners found that only 19% always performed the procedure themselves; many delegated the task to practice nurses, some of whom had received no instruction. This is problematic as the removal of cerumen is not without risk. Irrigation can be performed at home with proper equipment as long as the person is careful not to irrigate too hard. All other methods should only be carried out by individuals who have been sufficiently trained in the procedure.
Bull advised physicians: "After removal of wax, inspect thoroughly to make sure none remains. This advice might seem superfluous, but is frequently ignored." This was confirmed by Sharp et al., who, in a survey of 320 general practitioners, found that only 68% of doctors inspected the ear canal after syringing to check that the wax was removed. As a result, failure to remove the wax from the canal made up approximately 30% of the complications associated with the procedure. Other complications included otitis externa, pain, vertigo, tinnitus, and perforation of the ear drum. Based on this (single) study, a rate of major complications in 1/1000 ears syringed was suggested.
Claims arising from ear syringing mishaps account for about 25% of the total claims received by New Zealand's Accident Compensation Corporation ENT Medical Misadventure Committee. While high, this is not surprising, as ear syringing is an extremely common procedure. Grossan suggested that approximately 150,000 ears are irrigated each week in the United States, and about 40,000 per week in the United Kingdom. Extrapolating from data obtained in Edinburgh, Sharp et al. place this figure much higher, estimating that approximately 7000 ears are syringed per 100,000 population per annum. In the New Zealand claims mentioned above, perforation of the tympanic membrane was by far the most common injury resulting in significant disability.
## Cotton Swabs
It is generally advised not to use cotton swabs (Q-Tips or cotton buds) as these will likely push the wax farther down the ear canal and, if used carelessly, perforate the eardrum. Abrasion of the ear canal, particularly after water has entered from swimming or bathing, can lead the way to ear infection. Also, the cotton head may fall off and become lodged in the ear canal. Cotton swabs should be used only to clean the external ear.
## Alternative Practices
### Ear Candling
Ear candling, a folk medicine practice, is claimed to remove ear wax and improve ear health. It involves placing a hollow candle in the ear canal and lighting it; the rising hot air is believed to pull out wax and "toxins" from the ear. An earwax-like substance does indeed collect inside the ear candle as it burns - but it collects there even if the candle is placed in a clean, dry drinking glass instead of on an ear. Ear candles are a fringe remedy in North America and Europe, but the claimed benefits are not supported by scientific evidence. Ear candles can also drip hot melted candle wax inside a person's ear; if the hot wax lands on the eardrum, it can cause great pain and possible hearing damage. Seely, Quigley and Langman reported that, in a survey of 122 ENT physicians, 21 ear injuries were reported due to ear candling. Ernst, in a review of the literature, finds that ear candling has no real effect on earwax removal, and poses a danger of ear injuries. He concludes that ear candling is "a triumph of ignorance over science".
Ear candles also deposit candle wax into the bottom of the ear candle tube, which can be interpreted as ear wax, but is simply brown wax from the candle.
# Earwax in Whales
Many species of whale have an annual buildup of earwax, adding one, two, or four layers (depending upon the species) each year. Similar to the incremental dating method of dendrochronology for trees, the number of layers can be counted to determine the age of the whale after its death.
# Related Chapters
- Ear pick
- List of Mendelian traits in humans
# Further Reading
A comprehensive review of the physiology and pathophysiology of earwax can be found in a 1997 review article by Roeser and Ballachanda. See also the New York Times article on the Yoshiura earwax study. | Earwax
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Cerumen
# Overview
Earwax, also known by the medical term cerumen, is a yellowish, waxy substance secreted in the ear canal of humans and many other mammals. It plays an important role in the human ear canal, assisting in cleaning and lubrication, and also provides some protection from bacteria, fungi, and insects. Excess or impacted cerumen can press against the eardrum and/or occlude the external auditory canal and impair hearing.
# Production, Composition, and Different Types
Cerumen is produced in the outer third of the cartilaginous portion of the human ear canal. It is a mixture of viscous secretions from sebaceous glands and less-viscous ones from modified apocrine sweat glands.[1] The primary components of earwax are the final products in the HMG-CoA reductase pathway, namely, squalene, lanosterol, and cholesterol.
There are two distinct genetically determined types of earwax: the wet type, which is dominant, and the dry type, which is recessive. Asians and Native Americans are more likely to have the dry type of cerumen (grey and flaky), whereas Caucasians and Africans are more likely to have the wet type (honey-brown to dark-brown and moist).[2] Cerumen type has been used by anthropologists to track human migratory patterns, such as those of the Inuit.[3]
The difference in cerumen type has been tracked to a single base change (a single nucleotide polymorphism) in a gene known as "ATP-binding cassette C11 gene". In addition to affecting cerumen type, this mutation also reduces sweat production. The researchers conjecture that the reduction in sweat was beneficial to the ancestors of East Asians and Native Americans who are thought to have lived in cold climates.[4]
# Function
## Cleaning
Cleaning of the ear canal occurs as a result of the "conveyor belt" process of epithelial migration, aided by jaw movement.[5] Cells formed in the centre of the tympanic membrane migrate outwards from the umbo (at a rate equivalent to that of fingernail growth) to the walls of the ear canal, and accelerate towards the entrance of the ear canal. The cerumen in the canal is also carried outwards, taking with it any dirt, dust, and particulate matter that may have gathered in the canal. Jaw movement assists this process by dislodging debris attached to the walls of the ear canal, increasing the likelihood of its expulsion.
## Lubrication
Lubrication prevents desiccation, itching, and burning of the skin within the ear canal (known as asteatosis). The lubricative properties arise from the high lipid content of the sebum produced by the sebaceous glands. In wet-type cerumen at least, these lipids include cholesterol, squalene, and many long-chain fatty acids and alcohols.[6][7]
## Antibacterial and Antifungal Roles
While studies conducted up until the 1960s found little evidence supporting an antibacterial role for cerumen,[8] more recent studies have found that cerumen has a bactericidal effect on some strains of bacteria. Cerumen has been found to be effective in reducing the viability of a wide range of bacteria (sometimes by up to 99%), including Haemophilus influenzae, Staphylococcus aureus, and many variants of Escherichia coli.[9][10] The growth of two fungi commonly present in otomycosis was also significantly inhibited by human cerumen.[11] These antimicrobial properties are due principally to the presence of saturated fatty acids, lysozyme and, especially, to the relatively low pH of cerumen (typically around 6.1 in normal individuals[12]).
# Removal
Excessive cerumen may impede the passage of sound in the ear canal, causing conductive hearing loss. It is also estimated to be the cause of 60–80% of hearing aid faults.[13] As mentioned above, movement of the jaw helps the ears' natural cleaning process, so chewing gum and talking can both help. If this is insufficient, the most common method of cerumen removal by general practitioners is syringing with warm water (used by 95% of GPs[14]). A curette method is more likely to be used by otolaryngologists when the ear canal is partially occluded and the material is not adhering to the skin of the ear canal.
## Cerumenolysis
In cases of those who have the "wet-type" of earwax, it is usually necessary to soften wax before its removal. This process is referred to as cerumenolysis, and is achieved using a solution known as a cerumenolytic agent which is introduced into the ear canal. The most common home-remedy for this purpose is olive oil.[15] Other commercially available and common cerumenolytics include:
- [under multiple brand names] Carbamide peroxide (6.5%) and glycerine
- Sodium bicarbonate B.P.C. (sodium bicarbonate and glycerine)
- Various organic liquids (glycerol, almond oil, mineral oil, baby oil)
- Cerumol (arachis oil, turpentine and dichlorobenzene)
- Cerumenex (Triethanolamine, polypeptides and oleate-condensate)
- Exterol, Otex (UK brand name) (urea, hydrogen peroxide and glycerine)
- Docusate, a detergent,an active ingredient found in laxatives
A cerumenolytic should be used 2-3 times daily for 3-5 days prior to the cerumen extraction.[16] Although most commercially available cerumenolytics available in the U.S. are identical, containing carbamide peroxide (6.5%) and glycerine,[16] a 10% solution of sodium bicarbonate (baking soda) was found to be a more effective cerumenolytic than several commercially-available solutions (Cerumenex, Auralgan) and numerous organic liquids, including glycerine, olive oil, and alcohol.[17] Additionally, 1 mL of docusate was also found to be a more effective cerumenolytic than several commercially-available solutions (Cerumenex, Debrox) [2]. Docusate may be extracted from liquid preparations of laxatives, such as Colace.
A systematic review of studies of the effectiveness of topical preparations for the treatment of earwax[3] concluded that cerumenolysis is better than no treatment, but there is little to choose between oil- and water-based preparations (including plain water). Applying such a preparation half an hour before syringing is probably as effective as applying it for several days. Several days' treatment with some preparations not based on water or oil appears promising. More studies are needed.
## Syringing
Once the cerumen has been softened, it may be removed from the ear canal by irrigation. Ear syringing techniques are described in great detail by Wilson & Roeser,[16] and Blake et al.,[18] who advise pulling the external ear up and back, and aiming the nozzle of the syringe slightly upwards and backwards so that the water flows as a cascade along the roof of the canal. The irrigation solution flows out of the canal along its floor, taking wax and debris with it. The solution used to irrigate the ear canal is usually warm water,[18] normal saline,[19] sodium bicarbonate solution,[20] or a solution of water and vinegar to help prevent secondary infection.[18]
Patients generally prefer the irrigation solution to be warmed to body temperature,[19] as dizziness is a common side effect of syringing with fluids that are colder or warmer than body temperature. Sharp et al.[14] recommend 37 °C, while Blake et al.[18] recommend using water at 38 °C, one degree above body temperature, and stress that this should be checked with a thermometer.
A syringe should be used to gently stream water into the ear. For children the rate and speed should be lower. After irrigating, tip the head to allow the water to drain. Irrigation may need to be repeated several times. If the water stream hurts then the flow should be slower. It is better to irrigate too gently for a long period than irrigate too forcefully attempting to remove wax quickly. This procedure can be done at home in the shower using a self-use ear irrigation syringe with a right angle tip. After the wax is removed, the ear can be dried tipping the head then gently pulling the ear upwards to straighten the ear canal. If this does not remove enough water, the ear can be dried with a hair dryer set on low.
## Curette Method
The earwax is removed through the use of an ear pick, which physically dislodges the earwax and scoops it out of the ear canal. In the west, use of a curette or ear pick is often only done in the hands of health professionals; a modified curette having a safety stop to prevent deep insertion for self-use is available. Curetting earwax using an ear pick is common in East Asia. As the earwax of most East Asians is of the dry type, it is extremely easy to remove all earwax via light scraping with an ear pick as it simply falls out in large pieces or dry flakes, often on it's own.
## Hazards
A postal survey of British general practitioners[14] found that only 19% always performed the procedure themselves; many delegated the task to practice nurses, some of whom had received no instruction. This is problematic as the removal of cerumen is not without risk. Irrigation can be performed at home with proper equipment as long as the person is careful not to irrigate too hard. All other methods should only be carried out by individuals who have been sufficiently trained in the procedure.
Bull advised physicians: "After removal of wax, inspect thoroughly to make sure none remains. This advice might seem superfluous, but is frequently ignored."[20] This was confirmed by Sharp et al.,[14] who, in a survey of 320 general practitioners, found that only 68% of doctors inspected the ear canal after syringing to check that the wax was removed. As a result, failure to remove the wax from the canal made up approximately 30% of the complications associated with the procedure. Other complications included otitis externa, pain, vertigo, tinnitus, and perforation of the ear drum. Based on this (single) study, a rate of major complications in 1/1000 ears syringed was suggested.[14]
Claims arising from ear syringing mishaps account for about 25% of the total claims received by New Zealand's Accident Compensation Corporation ENT Medical Misadventure Committee.[18] While high, this is not surprising, as ear syringing is an extremely common procedure. Grossan suggested that approximately 150,000 ears are irrigated each week in the United States, and about 40,000 per week in the United Kingdom.[21] Extrapolating from data obtained in Edinburgh, Sharp et al.[14] place this figure much higher, estimating that approximately 7000 ears are syringed per 100,000 population per annum. In the New Zealand claims mentioned above, perforation of the tympanic membrane was by far the most common injury resulting in significant disability.
## Cotton Swabs
It is generally advised not to use cotton swabs (Q-Tips or cotton buds) as these will likely push the wax farther down the ear canal and, if used carelessly, perforate the eardrum. Abrasion of the ear canal, particularly after water has entered from swimming or bathing, can lead the way to ear infection. Also, the cotton head may fall off and become lodged in the ear canal. Cotton swabs should be used only to clean the external ear.
## Alternative Practices
### Ear Candling
Ear candling, a folk medicine practice, is claimed to remove ear wax and improve ear health. It involves placing a hollow candle in the ear canal and lighting it; the rising hot air is believed to pull out wax and "toxins" from the ear. An earwax-like substance does indeed collect inside the ear candle as it burns - but it collects there even if the candle is placed in a clean, dry drinking glass instead of on an ear. Ear candles are a fringe remedy in North America and Europe, but the claimed benefits are not supported by scientific evidence.[22] Ear candles can also drip hot melted candle wax inside a person's ear; if the hot wax lands on the eardrum, it can cause great pain and possible hearing damage.[23] Seely, Quigley and Langman reported that, in a survey of 122 ENT physicians, 21 ear injuries were reported due to ear candling.[24] Ernst, in a review of the literature, finds that ear candling has no real effect on earwax removal, and poses a danger of ear injuries. He concludes that ear candling is "a triumph of ignorance over science".[25]
Ear candles also deposit candle wax into the bottom of the ear candle tube, which can be interpreted as ear wax, but is simply brown wax from the candle.
# Earwax in Whales
Many species of whale have an annual buildup of earwax, adding one, two, or four layers (depending upon the species) each year. Similar to the incremental dating method of dendrochronology for trees, the number of layers can be counted to determine the age of the whale after its death.[26]
# Related Chapters
- Ear pick
- List of Mendelian traits in humans
# Further Reading
A comprehensive review of the physiology and pathophysiology of earwax can be found in a 1997 review article by Roeser and Ballachanda.[27] See also the New York Times article on the Yoshiura earwax study.[28] | https://www.wikidoc.org/index.php/Cerumen | |
02ec3c95aa00ee35a735073f8c3737a01018427f | wikidoc | Cervix | Cervix
# Overview
The cervix (from Latin "neck") is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. Approximately half its length is visible with appropriate medical equipment; the remainder lies above the vagina beyond view. It is occasionally called "cervix uteri", or "neck of the uterus".
# Anatomy
## Ectocervix
The portion projecting into the vagina is referred to as the portio vaginalis or ectocervix. On average, the ectocervix is 3 cm long and 2.5 cm wide. It has a convex, elliptical surface and is divided into anterior and posterior lips.
### External os
The ectocervix's opening is called the external os. The size and shape of the external os and the ectocervix varies widely with age, hormonal state, and whether the woman has had a vaginal birth. In women who have not had a vaginal birth the external os appears as a small, circular opening. In women who have had a vaginal birth, the ectocervix appears bulkier and the external os appears wider, more slit-like and gaping.
## Endocervical canal
The passageway between the external os and the uterine cavity is referred to as the endocervical canal. It varies widely in length and width, along with the cervix overall. Flattened anterior to posterior, the endocervical canal measures 7 to 8 mm at its widest in reproductive-aged women.
## Internal os
The endocervical canal terminates at the internal os which is the opening of the cervix inside the uterine cavity.
## Cervical crypts
There are pockets in the lining of the cervix known as cervical crypts. They function to produce cervical fluid.
# Histology
The epithelium of the cervix is nonkeratinized stratified squamous epithelium at the ectocervix, and simple columnar epithelium at the cervix proper. At certain times of life, the columnar epithelium is replaced by metaplastic squamous epithelium, and is then known as the transformation zone.
Nabothian cysts are often found in the cervix.
# Cervical mucus
After a menstrual period ends, the external os is blocked by mucus that is thick and acidic. This "infertile" mucus blocks spermatozoa from entering the uterus. For several days around the time of ovulation, "fertile" types of mucus are produced: they have a higher water content, are less acidic, and have a ferning pattern that helps guide spermatozoa through the cervix. This ferning is a branching pattern seen in the mucus when observed with low magnification.
Some methods of fertility awareness involve estimating a woman's periods of fertility and infertility by observing changes in her body. Among these changes are several involving the quality of her cervical mucus: the sensation it causes at the vulva, its elasticity (spinnbarkeit), its transparency, and the presence of ferning.
Most methods of hormonal contraception work primarily by preventing ovulation, but their effectiveness is increased because they prevent the fertile types of cervical mucus from being produced. Conversely, methods of thinning the mucus may help to achieve pregnancy. One suggested method is to take guaifenesin in the few days before ovulation.
During pregnancy the cervix is blocked by a special antibacterial mucosal plug which prevents infection, somewhat similar to its state during the infertile portion of the menstrual cycle. The mucus plug comes out as the cervix dilates in labor or shortly before.
# Cervical position
After menstruation and directly under the influence of estrogen, the cervix undergoes a series of changes in position and texture.
- During most of the menstrual cycle, the cervix remains firm, like the tip of the nose, and is positioned low and closed.
- However, as a woman approaches ovulation, the cervix becomes softer, and rises and opens in response to the high levels of estrogen present at ovulation. These changes, accompanied by the production of fertile types of cervical mucus, support the survival and movement of sperm.
# Functionality
During menstruation the cervix stretches open slightly to allow the endometrium to be shed. This stretching is believed to be part of the cramping pain that many women experience. Evidence for this is given by the fact that some women's cramps subside or disappear after their first vaginal birth because the cervical opening has widened.
During childbirth, contractions of the uterus will dilate the cervix up to 10 cm in diameter to allow the fetus to pass through.
During orgasm, the cervix convulses and the external os dilates. Dr. R. Robin Baker and Dr. Mark A. Bellis, both at the University of Manchester, first proposed that this behavior worked in such a way as to draw any semen in the vagina into the uterus, increasing the likelihood of conception. Later researchers, most notably Elisabeth A. Lloyd, have questioned the logic of this theory and the quality of the experimental data used to back it.
# Cervical cancer
In humans the cervix may be affected by cervical cancer, a particular form of cancer which is detectable by cytological study of epithelial cells removed from the cervix in a process known as the pap smear. Evidence now shows that those with exposure to HPV (human papilloma virus) are at increased risk for cervical cancer. These viruses are related to the viruses that causes warts. The incidence of new cases of cervical cancer in the United States was observed to be 7 per 100,000 women in 2004.
## Cervix: Squamous cell carcinoma
# Lymphatic drainage
The lymphatic drainage of the cervix is along the uterine arteries and cardinal ligaments to the parametrial, external iliac vein, internal iliac vein, and obturator and presacral lymph nodes. From these pelvic lymph nodes, drainage then proceeds to the paraaortic lymph nodes. In some women, the lymphatics drain directly to the paraaortic nodes.
# Additional images
- Organs of the female reproductive system.
- Ovary
- Uterus and uterine tubes.
- Posterior half of uterus and upper part of vagina.
- Mucus plug
# Histopathological Findings in Cervix Diseases
## Cervix: Bacterial vaginosis
## Cervix: Candida
## Cervix: Trichomonas | Cervix
Template:Infobox Anatomy
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Template:Editor help
# Overview
The cervix (from Latin "neck") is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. Approximately half its length is visible with appropriate medical equipment; the remainder lies above the vagina beyond view. It is occasionally called "cervix uteri", or "neck of the uterus".
# Anatomy
## Ectocervix
The portion projecting into the vagina is referred to as the portio vaginalis or ectocervix. On average, the ectocervix is 3 cm long and 2.5 cm wide. It has a convex, elliptical surface and is divided into anterior and posterior lips.
### External os
The ectocervix's opening is called the external os. The size and shape of the external os and the ectocervix varies widely with age, hormonal state, and whether the woman has had a vaginal birth. In women who have not had a vaginal birth the external os appears as a small, circular opening. In women who have had a vaginal birth, the ectocervix appears bulkier and the external os appears wider, more slit-like and gaping.
## Endocervical canal
The passageway between the external os and the uterine cavity is referred to as the endocervical canal. It varies widely in length and width, along with the cervix overall. Flattened anterior to posterior, the endocervical canal measures 7 to 8 mm at its widest in reproductive-aged women.
## Internal os
The endocervical canal terminates at the internal os which is the opening of the cervix inside the uterine cavity.
## Cervical crypts
There are pockets in the lining of the cervix known as cervical crypts. They function to produce cervical fluid.[1]
# Histology
The epithelium of the cervix is nonkeratinized stratified squamous epithelium at the ectocervix, and simple columnar epithelium at the cervix proper.[2][3] At certain times of life, the columnar epithelium is replaced by metaplastic squamous epithelium, and is then known as the transformation zone.
Nabothian cysts are often found in the cervix.[4]
# Cervical mucus
After a menstrual period ends, the external os is blocked by mucus that is thick and acidic. This "infertile" mucus blocks spermatozoa from entering the uterus.[5] For several days around the time of ovulation, "fertile" types of mucus are produced: they have a higher water content, are less acidic, and have a ferning pattern that helps guide spermatozoa through the cervix.[6] This ferning is a branching pattern seen in the mucus when observed with low magnification.
Some methods of fertility awareness involve estimating a woman's periods of fertility and infertility by observing changes in her body. Among these changes are several involving the quality of her cervical mucus: the sensation it causes at the vulva, its elasticity (spinnbarkeit), its transparency, and the presence of ferning.[6]
Most methods of hormonal contraception work primarily by preventing ovulation, but their effectiveness is increased because they prevent the fertile types of cervical mucus from being produced. Conversely, methods of thinning the mucus may help to achieve pregnancy. One suggested method is to take guaifenesin in the few days before ovulation.[7]
During pregnancy the cervix is blocked by a special antibacterial mucosal plug which prevents infection, somewhat similar to its state during the infertile portion of the menstrual cycle. The mucus plug comes out as the cervix dilates in labor or shortly before.
# Cervical position
After menstruation and directly under the influence of estrogen, the cervix undergoes a series of changes in position and texture.
- During most of the menstrual cycle, the cervix remains firm, like the tip of the nose, and is positioned low and closed.
- However, as a woman approaches ovulation, the cervix becomes softer, and rises and opens in response to the high levels of estrogen present at ovulation.[1] These changes, accompanied by the production of fertile types of cervical mucus, support the survival and movement of sperm.
# Functionality
During menstruation the cervix stretches open slightly to allow the endometrium to be shed. This stretching is believed to be part of the cramping pain that many women experience. Evidence for this is given by the fact that some women's cramps subside or disappear after their first vaginal birth because the cervical opening has widened.
During childbirth, contractions of the uterus will dilate the cervix up to 10 cm in diameter to allow the fetus to pass through.
During orgasm, the cervix convulses and the external os dilates. Dr. R. Robin Baker and Dr. Mark A. Bellis, both at the University of Manchester, first proposed that this behavior worked in such a way as to draw any semen in the vagina into the uterus, increasing the likelihood of conception. Later researchers, most notably Elisabeth A. Lloyd, have questioned the logic of this theory and the quality of the experimental data used to back it.
# Cervical cancer
In humans the cervix may be affected by cervical cancer, a particular form of cancer which is detectable by cytological study of epithelial cells removed from the cervix in a process known as the pap smear. Evidence now shows that those with exposure to HPV (human papilloma virus) are at increased risk for cervical cancer. These viruses are related to the viruses that causes warts. The incidence of new cases of cervical cancer in the United States was observed to be 7 per 100,000 women in 2004.[8]
## Cervix: Squamous cell carcinoma
# Lymphatic drainage
The lymphatic drainage of the cervix is along the uterine arteries and cardinal ligaments to the parametrial, external iliac vein, internal iliac vein, and obturator and presacral lymph nodes. From these pelvic lymph nodes, drainage then proceeds to the paraaortic lymph nodes. In some women, the lymphatics drain directly to the paraaortic nodes.
# Additional images
- Organs of the female reproductive system.
- Ovary
- Uterus and uterine tubes.
- Posterior half of uterus and upper part of vagina.
- Mucus plug
# Histopathological Findings in Cervix Diseases
## Cervix: Bacterial vaginosis
## Cervix: Candida
## Cervix: Trichomonas | https://www.wikidoc.org/index.php/Cervical_mucus | |
c819e1cf596f04803d5593e31a0ed77adfcadb54 | wikidoc | Cgk733 | Cgk733
CGK733 is a synthetic substance whose molecular structure is shown in the diagram.
It is a complex thiourea derivative which has remarkable properties in reversing cell senescence (aging).
Experiments have shown that it can extend the lifetime of cultured cells by approximately 20 divisions, or roughly 25%, specifically in mammalian cells. Current research is investigating its potential uses in wound healing, antiaging cosmetics and tissue engineering.
Tae Kook Kim and several associates at the Korea Advanced Institute of Science & Technology discovered its properties as a result of screening twenty thousand synthetic molecules for their effects on aging cells.
It is an inhibitor of ATM/ATR kinases, which are involved in DNA damage repair. | Cgk733
CGK733 is a synthetic substance whose molecular structure is shown in the diagram.[1]
It is a complex thiourea derivative which has remarkable properties in reversing cell senescence (aging).
Experiments have shown that it can extend the lifetime of cultured cells by approximately 20 divisions, or roughly 25%, specifically in mammalian cells. Current research is investigating its potential uses in wound healing, antiaging cosmetics and tissue engineering.
Tae Kook Kim[2] and several associates at the Korea Advanced Institute of Science & Technology discovered its properties as a result of screening twenty thousand synthetic molecules for their effects on aging cells.
It is an inhibitor of ATM/ATR kinases, which are involved in DNA damage repair. | https://www.wikidoc.org/index.php/Cgk733 | |
1de8ad33bc926cb6a98867d4be915b3f2cd9b34e | wikidoc | Cheese | Cheese
Sometimes used as a street name or slang for heroin and cold medicine combination.
Cheese is a food made from milk, usually the milk of cows, buffalo, goats, or sheep, by coagulation. The milk is acidified, typically with a bacterial culture, then the addition of the enzyme rennet or a substitute (e.g. acetic acid or vinegar) causes coagulation, to give "curds and whey". Some cheeses also have molds, either on the outer rind (similar to a fruit peel) or throughout.
Hundreds of types of cheese are produced. Their different styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether it has been pasteurized, butterfat content, the species of bacteria and mold, and the processing including the length of aging. Herbs, spices, or wood smoke may be used as flavoring agents. The yellow to red color of many cheeses is a result of adding annatto. Cheeses are eaten both on their own and cooked in various dishes; most cheeses melt when heated.
For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon juice. Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, then the addition of rennet completes the curdling. Vegetarian alternatives to rennet are available; most are produced by fermentation of the fungus Mucor miehei, but others have been extracted from various species of the Cynara thistle family.
Cheese has served as a hedge against famine and is a good travel food. It is valuable for its portability, long life, and high content of fat, protein, calcium, and phosphorus. Cheese is more compact and has a longer shelf life than the milk from which it is made. Cheesemakers near a dairy region may benefit from fresher, lower-priced milk, and lower shipping costs. The long storage life of cheese allows selling it when markets are more favorable.
# Etymology
The origin of the word cheese appears to be the Latin caseus, from which the modern word casein is closely derived. The earliest source is probably from the proto-Indo-European root *kwat-, which means "to ferment, become sour".
In the English language, the modern word cheese comes from chese (in Middle English) and cīese or cēse (in Old English). Similar words are shared by other West Germanic languages — West Frisian tsiis, Dutch kaas, German Käse, Old High German chāsi — all of which probably come from the reconstructed West-Germanic root *kasjus, which in turn is an early borrowing from Latin.
The Latin word caseus is also the source from which are derived the Spanish queso, Portuguese queijo, Malay/Indonesian Language keju (a borrowing from the Portuguese word queijo), Romanian caş and Italian cacio.
The Celtic root which gives the Irish cáis and the Welsh caws are also related.
When the Romans began to make hard cheeses for their legionaries' supplies, a new word started to be used: formaticum, from caseus formatus, or "molded cheese". It is from this word that we get the French fromage, Italian formaggio, Catalan formatge, Breton fourmaj and Provençal furmo. Cheese itself is occasionally employed in a sense that means "molded" or "formed". Head cheese uses the word in this sense.
# History
## Origins
Cheese is an ancient food whose origins predate recorded history. There is no conclusive evidence indicating where cheesemaking originated, either in Europe, Central Asia or the Middle East, but the practice had spread within Europe prior to Roman times and, according to Pliny the Elder, had become a sophisticated enterprise by the time the Roman Empire came into being.
Proposed dates for the origin of cheesemaking range from around 8000 BCE (when sheep were first domesticated) to around 3000 BCE. The first cheese may have been made by people in the Middle East or by nomadic Turkic tribes in Central Asia. Since animal skins and inflated internal organs have, since ancient times, provided storage vessels for a range of foodstuffs, it is probable that the process of cheese making was discovered accidentally by storing milk in a container made from the stomach of an animal, resulting in the milk being turned to curd and whey by the rennet from the stomach. There is a widely-told legend about the discovery of cheese by an Arab trader who used this method of storing milk. The legend has many individual variations.
Cheesemaking may also have begun independent of this by the pressing and salting of curdled milk in order to preserve it. Observation that the effect of making milk in an animal stomach gave more solid and better-textured curds, may have led to the deliberate addition of rennet.
The earliest archaeological evidence of cheesemaking has been found in Egyptian tomb murals, dating to about 2000 BCE. The earliest cheeses were likely to have been quite sour and salty, similar in texture to rustic cottage cheese or feta, a crumbly, flavorful Greek cheese.
Cheese produced in Europe, where climates are cooler than the Middle East, required less aggressive salting for preservation. In conditions of less salt and acidity, the cheese became a suitable environment for a variety of beneficial microbes and molds, which are what give aged cheeses their pronounced and interesting flavors.
Cheese has become the most popular milk invention.
## Ancient Greece and Rome
Ancient Greek mythology credited Aristaeus with the discovery of cheese. Homer's Odyssey (8th century BCE) describes the Cyclops making and storing sheep's and goats' milk cheese. From Samuel Butler's translation:
By Roman times, cheese was an everyday food and cheesemaking a mature art, not very different from what it is today. Columella's De Re Rustica (circa 65 CE) details a cheesemaking process involving rennet coagulation, pressing of the curd, salting, and aging. Pliny's Natural History (77 CE) devotes a chapter (XI, 97) to describing the diversity of cheeses enjoyed by Romans of the early Empire. He stated that the best cheeses came from the villages near Nîmes, but did not keep long and had to be eaten fresh. Cheeses of the Alps and Apennines were as remarkable for their variety then as now. A Ligurian cheese was noted for being made mostly from sheep's milk, and some cheeses produced nearby were stated to weigh as much as a thousand pounds each. Goats' milk cheese was a recent taste in Rome, improved over the "medicinal taste" of Gaul's similar cheeses by smoking. Of cheeses from overseas, Pliny preferred those of Bithynia in Asia Minor.
## Post-classical Europe
Rome spread a uniform set of cheesemaking techniques throughout much of Europe, and introduced cheesemaking to areas without a previous history of it. As Rome declined and long-distance trade collapsed, cheese in Europe diversified further, with various locales developing their own distinctive cheesemaking traditions and products. The British Cheese Board claims that Britain has approximately 700 distinct local cheeses; France and Italy have perhaps 400 each. (A French proverb holds there is a different French cheese for every day of the year, and Charles de Gaulle once asked "how can you govern a country in which there are 246 kinds of cheese?") Still, the advancement of the cheese art in Europe was slow during the centuries after Rome's fall. Many of the cheeses we know best today were first recorded in the late Middle Ages or after— cheeses like cheddar around 1500 CE, Parmesan in 1597, Gouda in 1697, and Camembert in 1791.
In 1546, John Heywood wrote in Proverbes that "the moon is made of a greene cheese." (Greene may refer here not to the color, as many now think, but to being new or unaged.) Variations on this sentiment were long repeated. Although some people assumed that this was a serious belief in the era before space exploration, it is more likely that Heywood was indulging in nonsense.
## Modern era
Until its modern spread along with European culture, cheese was nearly unheard of in oriental cultures, uninvented in the pre-Columbian Americas, and of only limited use in sub-mediterranean Africa, mainly being widespread and popular only in Europe and areas influenced strongly by its cultures. But with the spread, first of European imperialism, and later of Euro-American culture and food, cheese has gradually become known and increasingly popular worldwide, though still rarely considered a part of local ethnic cuisines outside Europe, the Middle East, and the Americas.
The first factory for the industrial production of cheese opened in Switzerland in 1815, but it was in the United States where large-scale production first found real success. Credit usually goes to Jesse Williams, a dairy farmer from Rome, New York, who in 1851 started making cheese in an assembly-line fashion using the milk from neighboring farms. Within decades hundreds of such dairy associations existed.
The 1860s saw the beginnings of mass-produced rennet, and by the turn of the century scientists were producing pure microbial cultures. Before then, bacteria in cheesemaking had come from the environment or from recycling an earlier batch's whey; the pure cultures meant a more standardized cheese could be produced.
Factory-made cheese overtook traditional cheesemaking in the World War II era, and factories have been the source of most cheese in America and Europe ever since. Today, Americans buy more processed cheese than "real", factory-made or not.
# Making cheese
## Curdling
The only strictly required step in making any sort of cheese is separating the milk into solid curds and liquid whey. Usually this is done by acidifying (souring) the milk and adding rennet. The acidification is accomplished directly by the addition of an acid like vinegar in a few cases (paneer, queso fresco), but usually starter bacteria are employed instead. These starter bacteria convert milk sugars into lactic acid. The same bacteria (and the enzymes they produce) also play a large role in the eventual flavor of aged cheeses. Most cheeses are made with starter bacteria from the Lactococci, Lactobacilli, or Streptococci families. Swiss starter cultures also include Propionibacter shermani, which produces carbon dioxide gas bubbles during aging, giving Swiss cheese or Emmental its holes.
Some fresh cheeses are curdled only by acidity, but most cheeses also use rennet. Rennet sets the cheese into a strong and rubbery gel compared to the fragile curds produced by acidic coagulation alone. It also allows curdling at a lower acidity—important because flavor-making bacteria are inhibited in high-acidity environments. In general, softer, smaller, fresher cheeses are curdled with a greater proportion of acid to rennet than harder, larger, longer-aged varieties.
## Curd processing
At this point, the cheese has set into a very moist gel. Some soft cheeses are now essentially complete: they are drained, salted, and packaged. For most of the rest, the curd is cut into small cubes. This allows water to drain from the individual pieces of curd.
Some hard cheeses are then heated to temperatures in the range of 35 °C–55 °C (100 °F–130 °F). This forces more whey from the cut curd. It also changes the taste of the finished cheese, affecting both the bacterial culture and the milk chemistry. Cheeses that are heated to the higher temperatures are usually made with thermophilic starter bacteria which survive this step—either lactobacilli or streptococci.
Salt has a number of roles in cheese besides adding a salty flavor. It preserves cheese from spoiling, draws moisture from the curd, and firms up a cheese’s texture in an interaction with its proteins. Some cheeses are salted from the outside with dry salt or brine washes. Most cheeses have the salt mixed directly into the curds.
A number of other techniques can be employed to influence the cheese's final texture and flavor. Some examples:
- Stretching: (Mozzarella, Provolone) The curd is stretched and kneaded in hot water, developing a stringy, fibrous body.
- Cheddaring: (Cheddar, other English cheeses) The cut curd is repeatedly piled up, pushing more moisture away. The curd is also mixed (or milled) for a long period of time, taking the sharp edges off the cut curd pieces and influencing the final product's texture.
- Washing: (Edam, Gouda, Colby) The curd is washed in warm water, lowering its acidity and making for a milder-tasting cheese.
Most cheeses achieve their final shape when the curds are pressed into a mold or form. The harder the cheese, the more pressure is applied. The pressure drives out moisture — the molds are designed to allow water to escape — and unifies the curds into a single solid body.
## Ageing
A newborn cheese is usually salty yet bland in flavor and, for harder varieties, rubbery in texture. These qualities are sometimes enjoyed—cheese curds are eaten on their own—but normally cheeses are left to rest under carefully controlled conditions. This ageing period (also called ripening, or, from the French, affinage) can last from a few days to several years. As a cheese ages, microbes and enzymes transform its texture and intensify its flavor. This transformation is largely a result of the breakdown of casein proteins and milkfat into a complex mix of amino acids, amines, and fatty acids.
Some cheeses have additional bacteria or molds intentionally introduced to them before or during ageing. In traditional cheesemaking, these microbes might be already present in the air of the ageing room; they are simply allowed to settle and grow on the stored cheeses. More often today, prepared cultures are used, giving more consistent results and putting fewer constraints on the environment where the cheese ages. These cheeses include soft ripened cheeses such as Brie and Camembert, blue cheeses such as Roquefort, Stilton, Gorgonzola, and rind-washed cheeses such as Limburger.
# Types
## Factors in categorization
Factors which are relevant to the categorization of cheeses include:
- Length of aging
- Texture
- Methods of making
- Fat content
- Kind of milk
- Country/Region of Origin
## List of common categories
No one categorization scheme can capture all the diversity of the world's cheeses.
In practice, no single system is employed and different factors are emphasised in describing different classes of cheeses. This typical list of cheese categories is from foodwriter Barbara Ensrud.
- Fresh
- Whey
- Pasta filata
- Semi-soft
- Semi-firm
- Hard
- Double and triple cream
- Soft-ripened
- Blue vein
- Goat or sheep
- Strong-smelling
- Processed
### Fresh, whey and stretched curd cheeses
The main factor in the categorization of these cheese is their age. Fresh cheeses without additional preservatives can spoil in a matter of days.
For these simplest cheeses, milk is curdled and drained, with little other processing. Examples include cottage cheese, Romanian Caş, Neufchâtel (the model for American-style cream cheese), and fresh goat's milk chèvre. Such cheeses are soft and spreadable, with a mild taste.
Whey cheeses are fresh cheeses made from the whey discarded while producing other cheeses. Provencal Brousse, Corsican Brocciu, Italian Ricotta, Romanian Urda, Greek Mizithra, and Norwegian Geitost are examples. Brocciu is mostly eaten fresh, and is as such a major ingredient in Corsican cuisine, but it can be aged too.
Traditional pasta filata cheeses such as Mozzarella also fall into the fresh cheese category. Fresh curds are stretched and kneaded in hot water to form a ball of Mozzarella, which in southern Italy is usually eaten within a few hours of being made. Stored in brine, it can be shipped, and is known world-wide for its use on pizzas. Other firm fresh cheeses include paneer and queso fresco.
### Classed by texture
Categorizing cheeses by firmness is a common but inexact practice. The lines between "soft", "semi-soft", "semi-hard", and "hard" are arbitrary, and many types of cheese are made in softer or firmer variations. The factor controlling the hardness of a cheese is its moisture content which is dependent on the pressure with which it is packed into molds and the length of time it is aged.
Semi-soft cheeses and the sub-group, Monastery cheeses have a high moisture content and tend to be bland in flavor. Some well-known varieties include Havarti, Munster and Port Salut.
Cheeses that range in texture from semi-soft to firm include Swiss-style cheeses like Emmental and Gruyère. The same bacteria that give such cheeses their holes also contribute to their aromatic and sharp flavors. Other semi-soft to firm cheeses include Gouda, Edam, Jarlsberg and Cantal. Cheeses of this type are ideal for melting and are used on toast for quick snacks.
Harder cheeses have a lower moisture content than softer cheeses. They are generally packed into molds under more pressure and aged for a longer time. Cheeses that are semi-hard to hard include the familiar cheddar, originating in the Cheddar Gorge of England but now used as a generic term for this style of cheese, of which varieties are imitated world-wide and are marketed by the length of time they have been aged.
Cheddar is one of a family of semi-hard or hard cheeses (including Cheshire and Gloucester) whose curd is cut, gently heated, piled, and stirred before being pressed into forms. Colby and Monterey Jack are similar but milder cheeses; their curd is rinsed before it is pressed, washing away some acidity and calcium. A similar curd-washing takes place when making the Dutch cheeses Edam and Gouda.
Hard cheeses — "grating cheeses" such as Parmesan and Pecorino Romano — are quite firmly packed into large forms and aged for months or years.
### Classed by content
Some cheeses are categorized by the source of the milk used to produce them or by the added fat content of the milk from which they are produced. While most of the world's commercially available cheese is made from cows' milk, many parts of the world also produce cheese from goats and sheep, well-known examples being Roquefort, produced in France, and Pecorino Romano, produced in Italy, from ewes's milk. One farm in Sweden also produces cheese from moose's milk. Sometimes cheeses of a similar style may be available made from milk of different sources, Fetta style cheeses, for example, being made from goats' milk in Greece and of sheep and cows milk elsewhere.
Double cream cheeses are soft cheeses of cows' milk which are enriched with cream so that their fat content is 60% or, in the case of triple creams, 75%.
### Blue-vein
There are three main categories of cheese in which the presence of mold is a significant feature: soft ripened cheeses, washed rind cheeses and blue cheeses.
Soft-ripened cheeses are those which begin firm and rather chalky in texture but are aged from the exterior inwards by exposing them to mold. The mold may be a velvety bloom of Penicillium candida or P. camemberti that forms a flexible white crust and contributes to the smooth, runny, or gooey textures and more intense flavors of these aged cheeses. Brie and Camembert, the most famous of these cheeses, are made by allowing white mold to grow on the outside of a soft cheese for a few days or weeks. Goats' milk cheeses are often treated in a similar manner, sometimes with white molds (Chèvre-Boîte) and sometimes with blue.
Washed-rind cheeses are soft in character and ripen inwards like those with white molds; however, they are treated differently. Washed rind cheeses are periodically cured in a solution of saltwater brine and other mold-bearing agents which may include beer, wine, brandy and spices, making their surfaces amenable to a class of bacteria Brevibacterium linens (the reddish-orange "smear bacteria") which impart pungent odors and distinctive flavors. Washed-rind cheeses can be soft (Limburger), semi-hard (Munster), or hard (Appenzeller). The same bacteria can also have some impact on cheeses that are simply ripened in humid conditions, like Camembert.
So-called Blue cheese is created by inoculating a cheese with Penicillium roqueforti or Penicillium glaucum. This is done while the cheese is still in the form of loosely pressed curds, and may be further enhanced by piercing a ripening block of cheese with skewers in an atmosphere in which the mold is prevalent. The mold grows within the cheese as it ages. These cheeses have distinct blue veins which gives them their name, and, often, assertive flavors. The molds may range from pale green to dark blue, and may be accompanied by white and crusty brown molds.Their texture can be soft or firm. Some of the most renowned cheeses are of this type, each with its own distinctive color, flavor, texture and smell. They include Roquefort, Gorgonzola, and Stilton.
### Processed cheeses
Processed cheese is made from traditional cheese and emulsifying salts, often with the addition of milk, more salt, preservatives, and food coloring. It is inexpensive, consistent, and melts smoothly. It is sold packaged and either pre-sliced or unsliced, in a number of varieties. It is also available in spraycans.
# Eating and cooking
At refrigerator temperatures, the fat in a piece of cheese is as hard as unsoftened butter, and its protein structure is stiff as well. Flavor and odor compounds are less easily liberated when cold. For improvements in flavor and texture, it is widely advised that cheeses be allowed to warm up to room temperature before eating. If the cheese is further warmed, to 26–32 °C (80–90 °F), the fats will begin to "sweat out" as they go beyond soft to fully liquid.
At higher temperatures, most cheeses melt. Rennet-curdled cheeses have a gel-like protein matrix that is broken down by heat. When enough protein bonds are broken, the cheese itself turns from a solid to a viscous liquid. Soft, high-moisture cheeses will melt at around 55 °C (Expression error: Missing operand for *. ), while hard, low-moisture cheeses such as Parmesan remain solid until they reach about 82 °C (Expression error: Missing operand for *. ). Acid-set cheeses, including halloumi, paneer, some whey cheeses and many varieties of fresh goat cheese, have a protein structure that remains intact at high temperatures. When cooked, these cheeses just get firmer as water evaporates.
Some cheeses, like raclette, melt smoothly; many tend to become stringy or suffer from a separation of their fats. Many of these can be coaxed into melting smoothly in the presence of acids or starch. Fondue, with wine providing the acidity, is a good example of a smoothly-melted cheese dish. Elastic stringiness is a quality that is sometimes enjoyed, in dishes including pizza and Welsh rabbit. Even a melted cheese eventually turns solid again, after enough moisture is cooked off. The saying "you can't melt cheese twice" (meaning "some things can only be done once") refers to the fact that oils leach out during the first melting and are gone, leaving the non-meltable solids behind.
As its temperature continues to rise, cheese will brown and eventually burn. Browned, partially-burned cheese has a particular distinct flavor of its own and is frequently used in cooking (e.g., sprinkling atop items before baking them).
# Health and nutrition
In general, cheese supplies a great deal of calcium, protein, and phosphorus. A 30 (Expression error: Missing operand for *. ) serving of cheddar cheese contains about 7 (Expression error: Missing operand for *. ) of protein and 200 milligrams of calcium. Nutritionally, cheese is essentially concentrated milk: it takes about 200 (Expression error: Missing operand for *. ) of milk to provide that much protein, and 150 (Expression error: Missing operand for *. ) to equal the calcium.
Cheese potentially shares milk's nutritional disadvantages as well. The Center for Science in the Public Interest describes cheese as America's number one source of saturated fat, adding that the average American ate 30 (Expression error: Missing operand for *. ) of cheese in the year 2000, up from 11 (Expression error: Missing operand for *. ) in 1970. Their recommendation is to limit full-fat cheese consumption to 2 (Expression error: Missing operand for *. ) a week. Whether cheese's highly saturated fat actually leads to an increased risk of heart disease is called into question when considering France and Greece, which lead the world in cheese eating (more than 14 /Expression error: Missing operand for *. a week per person, or over 45 /Expression error: Missing operand for *. a year) yet have relatively low rates of heart disease. This seeming discrepancy is called the French Paradox; the higher rates of consumption of red wine in these countries is often invoked as at least a partial explanation.
Some studies claim to show that cheeses including Cheddar, Mozzarella, Swiss and American can help to prevent tooth decay. Several mechanisms for this protection have been proposed:
- The calcium, protein, and phosphorus in cheese may act to protect tooth enamel.
- Cheese increases saliva flow, washing away acids and sugars.
- Cheese may have an antibacterial effect in the mouth.
## Controversy
### Effect on sleep
A study by the British Cheese Board in 2005 to determine the effect of cheese upon sleep and dreaming discovered that, contrary to the idea that cheese commonly causes nightmares, the effect of cheese upon sleep was positive. The majority of the two hundred people tested over a fortnight claimed beneficial results from consuming cheeses before going to bed, the cheese promoting good sleep. Six cheeses were tested and the findings were that the dreams produced were specific to the type of cheese. None was found to induce nightmares. However, the six cheeses were all British. The results might be entirely different if a wider range of cheeses were tested. Cheese contains tryptophan, an amino acid that has been found to relieve stress and induce sleep.
### Casein
Like other dairy products, cheese contains casein, a substance that when digested by humans breaks down into several chemicals, including casomorphine, an opioid peptide. In the early 1990s it was hypothesized that autism can be caused or aggravated by opioid peptides. Based on this hypothesis, diets that eliminate cheese and other dairy products are widely promoted. Studies supporting these claims have had significant flaws, so the data are inadequate to guide autism treatment recommendations.
### Lactose
Cheese is often avoided by those who are lactose intolerant, but ripened cheeses like Cheddar contain only about 5% of the lactose found in whole milk, and aged cheeses contain almost none. Nevertheless, people with severe lactose intolerance should avoid eating dairy cheese. As a natural product, the same kind of cheese may contain different amounts of lactose on different occasions, causing unexpected painful reactions. As an alternative, also for vegans, there is already a wide range of different soy cheese kinds available. Some people suffer reactions to amines found in cheese, particularly histamine and tyramine. Some aged cheeses contain significant concentrations of these amines, which can trigger symptoms mimicking an allergic reaction: headaches, rashes, and blood pressure elevations.
### Pasteurization
A number of food safety agencies around the world have warned of the risks of raw-milk cheeses. The U.S. Food and Drug Administration states that soft raw-milk cheeses can cause "serious infectious diseases including listeriosis, brucellosis, salmonellosis and tuberculosis". It is U.S. law since 1944 that all raw-milk cheeses (including imports since 1951) must be aged at least 60 days. Australia has a wide ban on raw-milk cheeses as well, though in recent years exceptions have been made for Swiss Gruyère, Emmental and Sbrinz, and for French Roquefort.
Government-imposed pasteurization is, itself, controversial. Some say these worries are overblown, pointing out that pasteurization of the milk used to make cheese does not ensure its safety in any case.
This is supported by statistics showing that in Europe (where young raw-milk cheeses are still legal in some countries), most cheese-related food poisoning incidents were traced to pasteurized cheeses.
Pregnant women may face an additional risk from cheese; the U.S. Centers for Disease Control has warned pregnant women against eating soft-ripened cheeses and blue-veined cheeses, due to the listeria risk, which can cause miscarriage or harm to the fetus during birth.
# World production and consumption
Worldwide, cheese is a major agricultural product. According to the Food and Agricultural Organization of the United Nations, over 18 million metric tons of cheese were produced worldwide in 2004. This is more than the yearly production of coffee beans, tea leaves, cocoa beans and tobacco combined. The largest producer of cheese is the United States, accounting for 30 percent of world production, followed by Germany and France.
The biggest exporter of cheese, by monetary value, is France; the second, Germany (although it is first by quantity). Among the top ten exporters, only Ireland, New Zealand, the Netherlands and Australia have a cheese production that is mainly export oriented: respectively 95 percent, 90 percent, 72 percent, and 65 percent of their cheese production is exported. Only 30 percent of French production, the world's largest exporter, is exported. The United States, the biggest world producer of cheese, is a marginal exporter, as most of its production is for the domestic market.
Germany is the largest importer of cheese. The UK and Italy are the second- and third-largest importers.
Greece is the world's largest (per capita) consumer of cheese, with 27.3 kg eaten by the average Greek. (Feta accounts for three-quarters of this consumption.) France is the second biggest consumer of cheese, with 24 kg by inhabitant. Emmental (used mainly as a cooking ingredient) and Camembert are the most common cheeses in France Italy is the third biggest consumer by person with 22.9 kg. In the U.S., the consumption of cheese is quickly increasing and has nearly tripled between 1970 and 2003. The consumption per person has reached, in 2003, 14.1 kg (31 pounds). Fior di latte (commonly known as mozzarella) is America's favorite cheese and accounts for nearly a third of its consumption, mainly because it is one of the main ingredients of pizza.
# Cultural attitudes
Although cheese is a vital source of nutrition in many regions of the world, and is extensively consumed in others, its use as a nutritional product is not universal.
Cheese is rarely found in East Asian dishes, as genetic traits impeding the digestion of dairy products are relatively common in that part of the world and hence such products are rare. However, East Asian sentiment against cheese is not universal; cheese made from yaks' (chhurpi) or mares' milk is common on the Asian steppes; the national dish of Bhutan, ema datsi, is made from homemade cheese and hot peppers and Yunnan cheese is produced by several ethnic minority groups in the Yunnan province of China by mixing water buffalo milk and rice vinegar. Cheese consumption is increasing in China, with annual sales more than doubling from 1996 to 2003 (to a still small 30 million U.S. dollars a year). Certain kinds of Chinese preserved bean curd are sometimes misleadingly referred to in English as "Chinese cheese", because of their texture and strong flavor.
Strict followers of the dietary laws of Islam and Judaism must avoid cheeses made with rennet from animals not slaughtered in a manner adhering to halal or kosher laws. Both faiths allow cheese made with vegetable-based rennet or with rennet made from animals that were processed in a halal or kosher manner. Many less-orthodox Jews also believe that rennet undergoes enough processing to change its nature entirely, and do not consider it to ever violate kosher law. (See Cheese and kashrut.) As cheese is a dairy food under kosher rules it cannot be eaten in the same meal with any meat.
Many vegetarians avoid any cheese made from animal-based rennet. Most widely available vegetarian cheeses are made using rennet produced by fermentation of the fungus Mucor miehei. Vegans and other dairy-avoiding vegetarians do not eat real cheese at all, but some vegetable-based cheese substitutes (usually soy-and almond-based) are available.
Even in cultures with long cheese traditions, it is not unusual to find people who perceive cheese - especially pungent-smelling or mold-bearing varieties such as Limburger or Roquefort - as unappetizing, unpalatable, or disgusting. Food-science writer Harold McGee proposes that cheese is such an acquired taste because it is produced through a process of controlled spoilage and many of the odor and flavor molecules in an aged cheese are the same found in rotten foods. He notes, "An aversion to the odor of decay has the obvious biological value of steering us away from possible food poisoning, so it is no wonder that an animal food that gives off whiffs of shoes and soil and the stable takes some getting used to."
Collecting cheese labels is called "tyrosemiophilia".
# In language
In modern English slang, something "cheesy" is kitsch, cheap, inauthentic, or of poor quality. One can also be "cheesed off" – unhappy or annoyed. Such negative connotations might derive from a ripe cheese's sometimes unpleasant odor. The odor almost certainly explains the use of "cutting the cheese" as a euphemism for flatulence and the term "cheesy feet" to mean feet which smell. A more upbeat use of slang is seen in "the big cheese", an expression referring to the most important person in a group, the "big shot" or "head honcho". This use of the word probably derived not from the word cheese, but from the Persian or Hindi word chiz, meaning a thing. "Cheese it" is a 1950s slang term that means "get away fast".
A more whimsical bit of American and Canadian slang refers to school buses as "cheese wagons", a reference to school bus yellow. Subjects of photographs are often encouraged to "say cheese!", as the word "cheese" contains the phoneme /i/, a long vowel which requires the lips to be stretched in the appearance of a smile. People from Wisconsin and the Netherlands, both centers of cheese production, have been called cheeseheads. This nickname has been embraced by Wisconsin sports fans – especially fans of the Green Bay Packers or Wisconsin Badgers – who are often seen in the stands sporting plastic or foam hats in the shape of giant cheese wedges. | Cheese
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Sometimes used as a street name or slang for heroin and cold medicine combination.
Cheese is a food made from milk, usually the milk of cows, buffalo, goats, or sheep, by coagulation. The milk is acidified, typically with a bacterial culture, then the addition of the enzyme rennet or a substitute (e.g. acetic acid or vinegar) causes coagulation, to give "curds and whey".[1] Some cheeses also have molds, either on the outer rind (similar to a fruit peel) or throughout.
Hundreds of types of cheese are produced. Their different styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether it has been pasteurized, butterfat content, the species of bacteria and mold, and the processing including the length of aging. Herbs, spices, or wood smoke may be used as flavoring agents. The yellow to red color of many cheeses is a result of adding annatto. Cheeses are eaten both on their own and cooked in various dishes; most cheeses melt when heated.
For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon juice. Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, then the addition of rennet completes the curdling. Vegetarian alternatives to rennet are available; most are produced by fermentation of the fungus Mucor miehei, but others have been extracted from various species of the Cynara thistle family.
Cheese has served as a hedge against famine and is a good travel food. It is valuable for its portability, long life, and high content of fat, protein, calcium, and phosphorus. Cheese is more compact and has a longer shelf life than the milk from which it is made. Cheesemakers near a dairy region may benefit from fresher, lower-priced milk, and lower shipping costs. The long storage life of cheese allows selling it when markets are more favorable.
# Etymology
The origin of the word cheese appears to be the Latin caseus,[2] from which the modern word casein is closely derived. The earliest source is probably from the proto-Indo-European root *kwat-, which means "to ferment, become sour".
In the English language, the modern word cheese comes from chese (in Middle English) and cīese or cēse (in Old English). Similar words are shared by other West Germanic languages — West Frisian tsiis, Dutch kaas, German Käse, Old High German chāsi — all of which probably come from the reconstructed West-Germanic root *kasjus, which in turn is an early borrowing from Latin.
The Latin word caseus is also the source from which are derived the Spanish queso, Portuguese queijo, Malay/Indonesian Language keju (a borrowing from the Portuguese word queijo), Romanian caş and Italian cacio.
The Celtic root which gives the Irish cáis and the Welsh caws are also related.
When the Romans began to make hard cheeses for their legionaries' supplies, a new word started to be used: formaticum, from caseus formatus, or "molded cheese". It is from this word that we get the French fromage, Italian formaggio, Catalan formatge, Breton fourmaj and Provençal furmo. Cheese itself is occasionally employed in a sense that means "molded" or "formed". Head cheese uses the word in this sense.
# History
## Origins
Cheese is an ancient food whose origins predate recorded history. There is no conclusive evidence indicating where cheesemaking originated, either in Europe, Central Asia or the Middle East, but the practice had spread within Europe prior to Roman times and, according to Pliny the Elder, had become a sophisticated enterprise by the time the Roman Empire came into being.
Proposed dates for the origin of cheesemaking range from around 8000 BCE (when sheep were first domesticated) to around 3000 BCE. The first cheese may have been made by people in the Middle East or by nomadic Turkic tribes in Central Asia. Since animal skins and inflated internal organs have, since ancient times, provided storage vessels for a range of foodstuffs, it is probable that the process of cheese making was discovered accidentally by storing milk in a container made from the stomach of an animal, resulting in the milk being turned to curd and whey by the rennet from the stomach. There is a widely-told legend about the discovery of cheese by an Arab trader who used this method of storing milk. The legend has many individual variations.[3][4]
Cheesemaking may also have begun independent of this by the pressing and salting of curdled milk in order to preserve it. Observation that the effect of making milk in an animal stomach gave more solid and better-textured curds, may have led to the deliberate addition of rennet.
The earliest archaeological evidence of cheesemaking has been found in Egyptian tomb murals, dating to about 2000 BCE.[5] The earliest cheeses were likely to have been quite sour and salty, similar in texture to rustic cottage cheese or feta, a crumbly, flavorful Greek cheese.
Cheese produced in Europe, where climates are cooler than the Middle East, required less aggressive salting for preservation. In conditions of less salt and acidity, the cheese became a suitable environment for a variety of beneficial microbes and molds, which are what give aged cheeses their pronounced and interesting flavors.
Cheese has become the most popular milk invention.
## Ancient Greece and Rome
Ancient Greek mythology credited Aristaeus with the discovery of cheese. Homer's Odyssey (8th century BCE) describes the Cyclops making and storing sheep's and goats' milk cheese. From Samuel Butler's translation:
By Roman times, cheese was an everyday food and cheesemaking a mature art, not very different from what it is today. Columella's De Re Rustica (circa 65 CE) details a cheesemaking process involving rennet coagulation, pressing of the curd, salting, and aging. Pliny's Natural History (77 CE) devotes a chapter (XI, 97) to describing the diversity of cheeses enjoyed by Romans of the early Empire. He stated that the best cheeses came from the villages near Nîmes, but did not keep long and had to be eaten fresh. Cheeses of the Alps and Apennines were as remarkable for their variety then as now. A Ligurian cheese was noted for being made mostly from sheep's milk, and some cheeses produced nearby were stated to weigh as much as a thousand pounds each. Goats' milk cheese was a recent taste in Rome, improved over the "medicinal taste" of Gaul's similar cheeses by smoking. Of cheeses from overseas, Pliny preferred those of Bithynia in Asia Minor.
## Post-classical Europe
Rome spread a uniform set of cheesemaking techniques throughout much of Europe, and introduced cheesemaking to areas without a previous history of it. As Rome declined and long-distance trade collapsed, cheese in Europe diversified further, with various locales developing their own distinctive cheesemaking traditions and products. The British Cheese Board claims that Britain has approximately 700 distinct local cheeses;[6] France and Italy have perhaps 400 each. (A French proverb holds there is a different French cheese for every day of the year, and Charles de Gaulle once asked "how can you govern a country in which there are 246 kinds of cheese?"[7]) Still, the advancement of the cheese art in Europe was slow during the centuries after Rome's fall. Many of the cheeses we know best today were first recorded in the late Middle Ages or after— cheeses like cheddar around 1500 CE, Parmesan in 1597, Gouda in 1697, and Camembert in 1791.[8]
In 1546, John Heywood wrote in Proverbes that "the moon is made of a greene cheese." (Greene may refer here not to the color, as many now think, but to being new or unaged.)[9] Variations on this sentiment were long repeated. Although some people assumed that this was a serious belief in the era before space exploration, it is more likely that Heywood was indulging in nonsense.
## Modern era
Until its modern spread along with European culture, cheese was nearly unheard of in oriental cultures, uninvented in the pre-Columbian Americas, and of only limited use in sub-mediterranean Africa, mainly being widespread and popular only in Europe and areas influenced strongly by its cultures. But with the spread, first of European imperialism, and later of Euro-American culture and food, cheese has gradually become known and increasingly popular worldwide, though still rarely considered a part of local ethnic cuisines outside Europe, the Middle East, and the Americas.
The first factory for the industrial production of cheese opened in Switzerland in 1815, but it was in the United States where large-scale production first found real success. Credit usually goes to Jesse Williams, a dairy farmer from Rome, New York, who in 1851 started making cheese in an assembly-line fashion using the milk from neighboring farms. Within decades hundreds of such dairy associations existed.
The 1860s saw the beginnings of mass-produced rennet, and by the turn of the century scientists were producing pure microbial cultures. Before then, bacteria in cheesemaking had come from the environment or from recycling an earlier batch's whey; the pure cultures meant a more standardized cheese could be produced.
Factory-made cheese overtook traditional cheesemaking in the World War II era, and factories have been the source of most cheese in America and Europe ever since. Today, Americans buy more processed cheese than "real", factory-made or not.[10]
# Making cheese
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## Curdling
The only strictly required step in making any sort of cheese is separating the milk into solid curds and liquid whey. Usually this is done by acidifying (souring) the milk and adding rennet. The acidification is accomplished directly by the addition of an acid like vinegar in a few cases (paneer, queso fresco), but usually starter bacteria are employed instead. These starter bacteria convert milk sugars into lactic acid. The same bacteria (and the enzymes they produce) also play a large role in the eventual flavor of aged cheeses. Most cheeses are made with starter bacteria from the Lactococci, Lactobacilli, or Streptococci families. Swiss starter cultures also include Propionibacter shermani, which produces carbon dioxide gas bubbles during aging, giving Swiss cheese or Emmental its holes.
Some fresh cheeses are curdled only by acidity, but most cheeses also use rennet. Rennet sets the cheese into a strong and rubbery gel compared to the fragile curds produced by acidic coagulation alone. It also allows curdling at a lower acidity—important because flavor-making bacteria are inhibited in high-acidity environments. In general, softer, smaller, fresher cheeses are curdled with a greater proportion of acid to rennet than harder, larger, longer-aged varieties.
## Curd processing
At this point, the cheese has set into a very moist gel. Some soft cheeses are now essentially complete: they are drained, salted, and packaged. For most of the rest, the curd is cut into small cubes. This allows water to drain from the individual pieces of curd.
Some hard cheeses are then heated to temperatures in the range of 35 °C–55 °C (100 °F–130 °F). This forces more whey from the cut curd. It also changes the taste of the finished cheese, affecting both the bacterial culture and the milk chemistry. Cheeses that are heated to the higher temperatures are usually made with thermophilic starter bacteria which survive this step—either lactobacilli or streptococci.
Salt has a number of roles in cheese besides adding a salty flavor. It preserves cheese from spoiling, draws moisture from the curd, and firms up a cheese’s texture in an interaction with its proteins. Some cheeses are salted from the outside with dry salt or brine washes. Most cheeses have the salt mixed directly into the curds.
A number of other techniques can be employed to influence the cheese's final texture and flavor. Some examples:
- Stretching: (Mozzarella, Provolone) The curd is stretched and kneaded in hot water, developing a stringy, fibrous body.
- Cheddaring: (Cheddar, other English cheeses) The cut curd is repeatedly piled up, pushing more moisture away. The curd is also mixed (or milled) for a long period of time, taking the sharp edges off the cut curd pieces and influencing the final product's texture.
- Washing: (Edam, Gouda, Colby) The curd is washed in warm water, lowering its acidity and making for a milder-tasting cheese.
Most cheeses achieve their final shape when the curds are pressed into a mold or form. The harder the cheese, the more pressure is applied. The pressure drives out moisture — the molds are designed to allow water to escape — and unifies the curds into a single solid body.
## Ageing
A newborn cheese is usually salty yet bland in flavor and, for harder varieties, rubbery in texture. These qualities are sometimes enjoyed—cheese curds are eaten on their own—but normally cheeses are left to rest under carefully controlled conditions. This ageing period (also called ripening, or, from the French, affinage) can last from a few days to several years. As a cheese ages, microbes and enzymes transform its texture and intensify its flavor. This transformation is largely a result of the breakdown of casein proteins and milkfat into a complex mix of amino acids, amines, and fatty acids.
Some cheeses have additional bacteria or molds intentionally introduced to them before or during ageing. In traditional cheesemaking, these microbes might be already present in the air of the ageing room; they are simply allowed to settle and grow on the stored cheeses. More often today, prepared cultures are used, giving more consistent results and putting fewer constraints on the environment where the cheese ages. These cheeses include soft ripened cheeses such as Brie and Camembert, blue cheeses such as Roquefort, Stilton, Gorgonzola, and rind-washed cheeses such as Limburger.
# Types
## Factors in categorization
Factors which are relevant to the categorization of cheeses include:
- Length of aging
- Texture
- Methods of making
- Fat content
- Kind of milk
- Country/Region of Origin
## List of common categories
No one categorization scheme can capture all the diversity of the world's cheeses.
In practice, no single system is employed and different factors are emphasised in describing different classes of cheeses. This typical list of cheese categories is from foodwriter Barbara Ensrud.[11]
- Fresh
- Whey
- Pasta filata
- Semi-soft
- Semi-firm
- Hard
- Double and triple cream
- Soft-ripened
- Blue vein
- Goat or sheep
- Strong-smelling
- Processed
### Fresh, whey and stretched curd cheeses
The main factor in the categorization of these cheese is their age. Fresh cheeses without additional preservatives can spoil in a matter of days.
For these simplest cheeses, milk is curdled and drained, with little other processing. Examples include cottage cheese, Romanian Caş, Neufchâtel (the model for American-style cream cheese), and fresh goat's milk chèvre. Such cheeses are soft and spreadable, with a mild taste.
Whey cheeses are fresh cheeses made from the whey discarded while producing other cheeses. Provencal Brousse, Corsican Brocciu, Italian Ricotta, Romanian Urda, Greek Mizithra, and Norwegian Geitost are examples. Brocciu is mostly eaten fresh, and is as such a major ingredient in Corsican cuisine, but it can be aged too.
Traditional pasta filata cheeses such as Mozzarella also fall into the fresh cheese category. Fresh curds are stretched and kneaded in hot water to form a ball of Mozzarella, which in southern Italy is usually eaten within a few hours of being made. Stored in brine, it can be shipped, and is known world-wide for its use on pizzas. Other firm fresh cheeses include paneer and queso fresco.
### Classed by texture
Categorizing cheeses by firmness is a common but inexact practice. The lines between "soft", "semi-soft", "semi-hard", and "hard" are arbitrary, and many types of cheese are made in softer or firmer variations. The factor controlling the hardness of a cheese is its moisture content which is dependent on the pressure with which it is packed into molds and the length of time it is aged.
Semi-soft cheeses and the sub-group, Monastery cheeses have a high moisture content and tend to be bland in flavor. Some well-known varieties include Havarti, Munster and Port Salut.
Cheeses that range in texture from semi-soft to firm include Swiss-style cheeses like Emmental and Gruyère. The same bacteria that give such cheeses their holes also contribute to their aromatic and sharp flavors. Other semi-soft to firm cheeses include Gouda, Edam, Jarlsberg and Cantal. Cheeses of this type are ideal for melting and are used on toast for quick snacks.
Harder cheeses have a lower moisture content than softer cheeses. They are generally packed into molds under more pressure and aged for a longer time. Cheeses that are semi-hard to hard include the familiar cheddar, originating in the Cheddar Gorge of England but now used as a generic term for this style of cheese, of which varieties are imitated world-wide and are marketed by the length of time they have been aged.
Cheddar is one of a family of semi-hard or hard cheeses (including Cheshire and Gloucester) whose curd is cut, gently heated, piled, and stirred before being pressed into forms. Colby and Monterey Jack are similar but milder cheeses; their curd is rinsed before it is pressed, washing away some acidity and calcium. A similar curd-washing takes place when making the Dutch cheeses Edam and Gouda.
Hard cheeses — "grating cheeses" such as Parmesan and Pecorino Romano — are quite firmly packed into large forms and aged for months or years.
### Classed by content
Some cheeses are categorized by the source of the milk used to produce them or by the added fat content of the milk from which they are produced. While most of the world's commercially available cheese is made from cows' milk, many parts of the world also produce cheese from goats and sheep, well-known examples being Roquefort, produced in France, and Pecorino Romano, produced in Italy, from ewes's milk. One farm in Sweden also produces cheese from moose's milk.[12] Sometimes cheeses of a similar style may be available made from milk of different sources, Fetta style cheeses, for example, being made from goats' milk in Greece and of sheep and cows milk elsewhere.
Double cream cheeses are soft cheeses of cows' milk which are enriched with cream so that their fat content is 60% or, in the case of triple creams, 75%.
### Blue-vein
There are three main categories of cheese in which the presence of mold is a significant feature: soft ripened cheeses, washed rind cheeses and blue cheeses.
Soft-ripened cheeses are those which begin firm and rather chalky in texture but are aged from the exterior inwards by exposing them to mold. The mold may be a velvety bloom of Penicillium candida or P. camemberti that forms a flexible white crust and contributes to the smooth, runny, or gooey textures and more intense flavors of these aged cheeses. Brie and Camembert, the most famous of these cheeses, are made by allowing white mold to grow on the outside of a soft cheese for a few days or weeks. Goats' milk cheeses are often treated in a similar manner, sometimes with white molds (Chèvre-Boîte) and sometimes with blue.
Washed-rind cheeses are soft in character and ripen inwards like those with white molds; however, they are treated differently. Washed rind cheeses are periodically cured in a solution of saltwater brine and other mold-bearing agents which may include beer, wine, brandy and spices, making their surfaces amenable to a class of bacteria Brevibacterium linens (the reddish-orange "smear bacteria") which impart pungent odors and distinctive flavors. Washed-rind cheeses can be soft (Limburger), semi-hard (Munster), or hard (Appenzeller). The same bacteria can also have some impact on cheeses that are simply ripened in humid conditions, like Camembert.
So-called Blue cheese is created by inoculating a cheese with Penicillium roqueforti or Penicillium glaucum. This is done while the cheese is still in the form of loosely pressed curds, and may be further enhanced by piercing a ripening block of cheese with skewers in an atmosphere in which the mold is prevalent. The mold grows within the cheese as it ages. These cheeses have distinct blue veins which gives them their name, and, often, assertive flavors. The molds may range from pale green to dark blue, and may be accompanied by white and crusty brown molds.Their texture can be soft or firm. Some of the most renowned cheeses are of this type, each with its own distinctive color, flavor, texture and smell. They include Roquefort, Gorgonzola, and Stilton.
### Processed cheeses
Processed cheese is made from traditional cheese and emulsifying salts, often with the addition of milk, more salt, preservatives, and food coloring. It is inexpensive, consistent, and melts smoothly. It is sold packaged and either pre-sliced or unsliced, in a number of varieties. It is also available in spraycans.
# Eating and cooking
At refrigerator temperatures, the fat in a piece of cheese is as hard as unsoftened butter, and its protein structure is stiff as well. Flavor and odor compounds are less easily liberated when cold. For improvements in flavor and texture, it is widely advised that cheeses be allowed to warm up to room temperature before eating. If the cheese is further warmed, to 26–32 °C (80–90 °F), the fats will begin to "sweat out" as they go beyond soft to fully liquid.[13]
At higher temperatures, most cheeses melt. Rennet-curdled cheeses have a gel-like protein matrix that is broken down by heat. When enough protein bonds are broken, the cheese itself turns from a solid to a viscous liquid. Soft, high-moisture cheeses will melt at around 55 °C (Expression error: Missing operand for *. ), while hard, low-moisture cheeses such as Parmesan remain solid until they reach about 82 °C (Expression error: Missing operand for *. ).[14] Acid-set cheeses, including halloumi, paneer, some whey cheeses and many varieties of fresh goat cheese, have a protein structure that remains intact at high temperatures. When cooked, these cheeses just get firmer as water evaporates.
Some cheeses, like raclette, melt smoothly; many tend to become stringy or suffer from a separation of their fats. Many of these can be coaxed into melting smoothly in the presence of acids or starch. Fondue, with wine providing the acidity, is a good example of a smoothly-melted cheese dish.[15] Elastic stringiness is a quality that is sometimes enjoyed, in dishes including pizza and Welsh rabbit. Even a melted cheese eventually turns solid again, after enough moisture is cooked off. The saying "you can't melt cheese twice" (meaning "some things can only be done once") refers to the fact that oils leach out during the first melting and are gone, leaving the non-meltable solids behind.
As its temperature continues to rise, cheese will brown and eventually burn. Browned, partially-burned cheese has a particular distinct flavor of its own and is frequently used in cooking (e.g., sprinkling atop items before baking them).
# Health and nutrition
In general, cheese supplies a great deal of calcium, protein, and phosphorus. A 30 (Expression error: Missing operand for *. ) serving of cheddar cheese contains about 7 (Expression error: Missing operand for *. ) of protein and 200 milligrams of calcium. Nutritionally, cheese is essentially concentrated milk: it takes about 200 (Expression error: Missing operand for *. ) of milk to provide that much protein, and 150 (Expression error: Missing operand for *. ) to equal the calcium.[16]
Cheese potentially shares milk's nutritional disadvantages as well. The Center for Science in the Public Interest describes cheese as America's number one source of saturated fat, adding that the average American ate 30 (Expression error: Missing operand for *. ) of cheese in the year 2000, up from 11 (Expression error: Missing operand for *. ) in 1970.[17] Their recommendation is to limit full-fat cheese consumption to 2 (Expression error: Missing operand for *. ) a week. Whether cheese's highly saturated fat actually leads to an increased risk of heart disease is called into question when considering France and Greece, which lead the world in cheese eating (more than 14 /Expression error: Missing operand for *. a week per person, or over 45 /Expression error: Missing operand for *. a year) yet have relatively low rates of heart disease.[18] This seeming discrepancy is called the French Paradox; the higher rates of consumption of red wine in these countries is often invoked as at least a partial explanation.
Some studies claim to show that cheeses including Cheddar, Mozzarella, Swiss and American can help to prevent tooth decay.[19][20] Several mechanisms for this protection have been proposed:
- The calcium, protein, and phosphorus in cheese may act to protect tooth enamel.
- Cheese increases saliva flow, washing away acids and sugars.
- Cheese may have an antibacterial effect in the mouth.[citation needed]
## Controversy
### Effect on sleep
A study by the British Cheese Board in 2005 to determine the effect of cheese upon sleep and dreaming discovered that, contrary to the idea that cheese commonly causes nightmares, the effect of cheese upon sleep was positive. The majority of the two hundred people tested over a fortnight claimed beneficial results from consuming cheeses before going to bed, the cheese promoting good sleep. Six cheeses were tested and the findings were that the dreams produced were specific to the type of cheese. None was found to induce nightmares. However, the six cheeses were all British. The results might be entirely different if a wider range of cheeses were tested.[21] Cheese contains tryptophan, an amino acid that has been found to relieve stress and induce sleep.[22]
### Casein
Like other dairy products, cheese contains casein, a substance that when digested by humans breaks down into several chemicals, including casomorphine, an opioid peptide. In the early 1990s it was hypothesized that autism can be caused or aggravated by opioid peptides.[23] Based on this hypothesis, diets that eliminate cheese and other dairy products are widely promoted. Studies supporting these claims have had significant flaws, so the data are inadequate to guide autism treatment recommendations.[24]
### Lactose
Cheese is often avoided by those who are lactose intolerant, but ripened cheeses like Cheddar contain only about 5% of the lactose found in whole milk, and aged cheeses contain almost none.[25] Nevertheless, people with severe lactose intolerance should avoid eating dairy cheese. As a natural product, the same kind of cheese may contain different amounts of lactose on different occasions, causing unexpected painful reactions. As an alternative, also for vegans, there is already a wide range of different soy cheese kinds available. Some people suffer reactions to amines found in cheese, particularly histamine and tyramine. Some aged cheeses contain significant concentrations of these amines, which can trigger symptoms mimicking an allergic reaction: headaches, rashes, and blood pressure elevations.
### Pasteurization
A number of food safety agencies around the world have warned of the risks of raw-milk cheeses. The U.S. Food and Drug Administration states that soft raw-milk cheeses can cause "serious infectious diseases including listeriosis, brucellosis, salmonellosis and tuberculosis".[26] It is U.S. law since 1944 that all raw-milk cheeses (including imports since 1951) must be aged at least 60 days. Australia has a wide ban on raw-milk cheeses as well, though in recent years exceptions have been made for Swiss Gruyère, Emmental and Sbrinz, and for French Roquefort.[27]
Government-imposed pasteurization is, itself, controversial. Some say these worries are overblown, pointing out that pasteurization of the milk used to make cheese does not ensure its safety in any case.[28]
This is supported by statistics showing that in Europe (where young raw-milk cheeses are still legal in some countries), most cheese-related food poisoning incidents were traced to pasteurized cheeses.
Pregnant women may face an additional risk from cheese; the U.S. Centers for Disease Control has warned pregnant women against eating soft-ripened cheeses and blue-veined cheeses, due to the listeria risk, which can cause miscarriage or harm to the fetus during birth.[29]
# World production and consumption
Worldwide, cheese is a major agricultural product. According to the Food and Agricultural Organization of the United Nations, over 18 million metric tons of cheese were produced worldwide in 2004. This is more than the yearly production of coffee beans, tea leaves, cocoa beans and tobacco combined. The largest producer of cheese is the United States, accounting for 30 percent of world production, followed by Germany and France.
The biggest exporter of cheese, by monetary value, is France; the second, Germany (although it is first by quantity). Among the top ten exporters, only Ireland, New Zealand, the Netherlands and Australia have a cheese production that is mainly export oriented: respectively 95 percent, 90 percent, 72 percent, and 65 percent of their cheese production is exported.[31] Only 30 percent of French production, the world's largest exporter, is exported. The United States, the biggest world producer of cheese, is a marginal exporter, as most of its production is for the domestic market.
Germany is the largest importer of cheese. The UK and Italy are the second- and third-largest importers.[33]
Greece is the world's largest (per capita) consumer of cheese, with 27.3 kg eaten by the average Greek. (Feta accounts for three-quarters of this consumption.) France is the second biggest consumer of cheese, with 24 kg by inhabitant. Emmental (used mainly as a cooking ingredient) and Camembert are the most common cheeses in France[35] Italy is the third biggest consumer by person with 22.9 kg. In the U.S., the consumption of cheese is quickly increasing and has nearly tripled between 1970 and 2003. The consumption per person has reached, in 2003, 14.1 kg (31 pounds). Fior di latte (commonly known as mozzarella) is America's favorite cheese and accounts for nearly a third of its consumption, mainly because it is one of the main ingredients of pizza.[36]
# Cultural attitudes
Although cheese is a vital source of nutrition in many regions of the world, and is extensively consumed in others, its use as a nutritional product is not universal.
Cheese is rarely found in East Asian dishes, as genetic traits impeding the digestion of dairy products are relatively common in that part of the world and hence such products are rare. However, East Asian sentiment against cheese is not universal; cheese made from yaks' (chhurpi) or mares' milk is common on the Asian steppes; the national dish of Bhutan, ema datsi, is made from homemade cheese and hot peppers and Yunnan cheese is produced by several ethnic minority groups in the Yunnan province of China by mixing water buffalo milk and rice vinegar. Cheese consumption is increasing in China, with annual sales more than doubling from 1996 to 2003 (to a still small 30 million U.S. dollars a year).[37] Certain kinds of Chinese preserved bean curd are sometimes misleadingly referred to in English as "Chinese cheese", because of their texture and strong flavor.
Strict followers of the dietary laws of Islam and Judaism must avoid cheeses made with rennet from animals not slaughtered in a manner adhering to halal or kosher laws.[38] Both faiths allow cheese made with vegetable-based rennet or with rennet made from animals that were processed in a halal or kosher manner. Many less-orthodox Jews also believe that rennet undergoes enough processing to change its nature entirely, and do not consider it to ever violate kosher law. (See Cheese and kashrut.) As cheese is a dairy food under kosher rules it cannot be eaten in the same meal with any meat.
Many vegetarians avoid any cheese made from animal-based rennet. Most widely available vegetarian cheeses are made using rennet produced by fermentation of the fungus Mucor miehei. Vegans and other dairy-avoiding vegetarians do not eat real cheese at all, but some vegetable-based cheese substitutes (usually soy-and almond-based) are available.
Even in cultures with long cheese traditions, it is not unusual to find people who perceive cheese - especially pungent-smelling or mold-bearing varieties such as Limburger or Roquefort - as unappetizing, unpalatable, or disgusting. Food-science writer Harold McGee proposes that cheese is such an acquired taste because it is produced through a process of controlled spoilage and many of the odor and flavor molecules in an aged cheese are the same found in rotten foods. He notes, "An aversion to the odor of decay has the obvious biological value of steering us away from possible food poisoning, so it is no wonder that an animal food that gives off whiffs of shoes and soil and the stable takes some getting used to."[39]
Collecting cheese labels is called "tyrosemiophilia".[40]
# In language
In modern English slang, something "cheesy" is kitsch, cheap, inauthentic, or of poor quality. One can also be "cheesed off" – unhappy or annoyed. Such negative connotations might derive from a ripe cheese's sometimes unpleasant odor. The odor almost certainly explains the use of "cutting the cheese" as a euphemism for flatulence and the term "cheesy feet" to mean feet which smell. A more upbeat use of slang is seen in "the big cheese", an expression referring to the most important person in a group, the "big shot" or "head honcho". This use of the word probably derived not from the word cheese, but from the Persian or Hindi word chiz, meaning a thing.[41] "Cheese it" is a 1950s slang term that means "get away fast".
A more whimsical bit of American and Canadian slang refers to school buses as "cheese wagons", a reference to school bus yellow. Subjects of photographs are often encouraged to "say cheese!", as the word "cheese" contains the phoneme /i/, a long vowel which requires the lips to be stretched in the appearance of a smile.[42] People from Wisconsin and the Netherlands, both centers of cheese production, have been called cheeseheads. This nickname has been embraced by Wisconsin sports fans – especially fans of the Green Bay Packers or Wisconsin Badgers – who are often seen in the stands sporting plastic or foam hats in the shape of giant cheese wedges. | https://www.wikidoc.org/index.php/Cheese | |
596679682b80f3027f05e8ef909c32a0aa55aa14 | wikidoc | Energy | Energy
In physics and other sciences, energy (from the Greek ενεργός, energos, "active, working") is a scalar physical quantity that is a property of objects and systems which is conserved by nature. Energy is often defined as the ability to do work.
Several different forms of energy, such as kinetic, potential, thermal, chemical, nuclear, and mass have been defined to explain all known natural phenomena.
Energy is converted from one form to another, but it is never created or destroyed. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.
Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but nonzero kinetic energy relative to the earth.
# History
The concept of energy emerged out of the idea of vis viva, which Leibniz defined as the product of the mass of an object and its velocity squared; he believed that total vis viva was conserved. To account for slowing due to friction, Leibniz claimed that heat consisted of the random motion of the constituent parts of matter — a view shared by Isaac Newton, although it would be more than a century until this was generally accepted. In 1807, Thomas Young was the first to use the term "energy", instead of vis viva, in its modern sense. Gustave-Gaspard Coriolis described "kinetic energy" in 1829 in its modern sense, and in 1853, William Rankine coined the term "potential energy."
It was argued for some years whether energy was a substance (the caloric) or merely a physical quantity, such as momentum.
He amalgamated all of these laws into the laws of thermodynamics, which aided in the rapid development of explanations of chemical processes using the concept of energy by Rudolf Clausius, Josiah Willard Gibbs and Walther Nernst. It also led to a mathematical formulation of the concept of entropy by Clausius, and to the introduction of laws of radiant energy by Jožef Stefan.
During a 1961 lecture for undergraduate students at the California Institute of Technology, Richard Feynman, a celebrated physics teacher and Nobel Laureate, said this about the concept of energy:
Since 1918 it has been known that the law of conservation of energy is the direct mathematical consequence of the translational symmetry of the quantity conjugate to energy, namely time. That is, energy is conserved because the laws of physics do not distinguish between different moments of time (see Noether's theorem).
# Energy in various contexts since the beginning of the universe
The concept of energy and its transformations is extremely useful in explaining and predicting most natural phenomena. The direction of transformations in energy (what kind of energy is transformed to what other kind) is often described by entropy (equal energy spread among all available degrees of freedom) considerations, since in practice all energy transformations are permitted on a small scale, but certain larger transformations are not permitted because it is statistically unlikely that energy or matter will randomly move into more concentrated forms or smaller spaces.
The concept of energy is used often in all fields of science.
Energy transformations in the universe over time are characterized by various kinds of potential energy which has been available since the Big Bang, later being "released" (transformed to more active types of energy such as kinetic or radiant energy), when a triggering mechanism is available. Familiar examples of such processes include nuclear decay, in which energy is released which was originally "stored" in heavy isotopes (such as uranium and thorium), using the gravitational potential energy released from the gravitational collapse of supernovae, which created these elements before they were incorporated into the solar system and the Earth. Heat from such nuclear decay in the core of the Earth releases heat, which in turn may lift mountains via orogenesis. This lifting represents a kind of gravitational potential energy storage, which may be released to active kinetic energy in landslides, after a triggering event. Earthquakes also release stored elastic potential energy in rocks, a store which has been produced ultimately from the same heat sources. Thus, according to present understanding, familiar events such as landslides and earthquakes release energy stored since the collapse of long-destroyed stars.
In another similar chain of transformations from the dawn of the universe, nuclear fussion of hydrogen in the Sun releases potential energy stored at the time of the Big Bang, when according to theory, space expanded and the universe cooled too rapidly for hydrogen to completely fuse into heavier elements. Energy from this fusion process is triggered by heat and pressure generated from gravitational collapse of hydrogen clouds when they produce stars, and some of the energy is transformed to sunlight. Such sunlight from our Sun may again be stored as gravitational potential energy after it strikes the Earth, when (for example) water evaporates from oceans and is deposited upon mountains (where, after being released at a hydroelectric dam, it can be used to drive turbine/generators to produce electricity). Sunlight also drives all weather phenomenon, including violent events triggered when large unstable areas of warm ocean, heated over months, give up some of their thermal energy suddently to power a few days of hurricanes. Sunlight is also is captured by plants as chemical potential energy, when carbon dioxide and water are converted into carbohydrates, lipids, and oxygen. This energy may be triggered suddenly by a spark in a forest fire; or may be available more slowly for animal or human metabolism, when these molecules are ingested, and catabolism is triggered by enzyme action. Through all of these tranformation chains, potential energy stored at the time of the Big Bang is later released by intermediate events, sometimes being stored in a number of ways over time between releases as more active energy. In all these events, one kind of energy is converted to other types of energy, including heat.
# Regarding applications of the concept of energy
Energy is subject to a strict global conservation law; that is, whenever one measures (or calculates) the total energy of a system of particles whose interactions do not depend explicitly on time, it is found that the total energy of the system always remains constant.
- The total energy of a system can be subdivided and classified in various ways. For example, it is sometimes convenient to distinguish potential energy (which is a function of coordinates only) from kinetic energy (which is a function of coordinate time derivatives only). It may also be convenient to distinguish gravitational energy, electric energy, thermal energy, and other forms. These classifications overlap; for instance thermal energy usually consists partly of kinetic and partly of potential energy.
- The transfer of energy can take various forms; familiar examples include work, heat flow, and advection, as discussed below.
- The word "energy" is also used outside of physics in many ways, which can lead to ambiguity and inconsistency. The vernacular terminology is not consistent with technical terminology. For example, the important public-service announcement, "Please conserve energy" uses vernacular notions of "conservation" and "energy" which make sense in their own context but are utterly incompatible with the technical notions of "conservation" and "energy" (such as are used in the law of conservation of energy).
In classical physics energy is considered a scalar quantity, the canonical conjugate to time. In special relativity energy is also a scalar (although not a Lorentz scalar but a time component of the energy-momentum 4-vector). In other words, energy is invariant with respect to rotations of space, but not invariant with respect to rotations of space-time (= boosts).
## Energy transfer
Because energy is strictly conserved and is also locally conserved (wherever it can be defined), it is important to remember that by definition of energy the transfer of energy between the "system" and adjacent regions is work. A familiar example is mechanical work. In simple cases this is written as:
if there are no other energy-transfer processes involved. Here \Delta{}E is the amount of energy transferred, and W represents the work done on the system.
More generally, the energy transfer can be split into two categories:
where Q represents the heat flow into the system.
There are other ways in which an open system can gain or lose energy. If mass is counted as energy (as in many relativistic problems) then E must contain a term for mass lost or gained. In chemical systems, energy can be added to a system by means of adding substances with different chemical potentials, which potentials are then extracted (both of these process are illustrated by fueling an auto, a system which gains in energy thereby, without addition of either work or heat). These terms may be added to the above equation, or they can generally be subsumed into a quantity called "energy addition term E" which refers to any type of energy carried over the surface of a control volume or system volume. Examples may be seen above, and many others can be imagined (for example, the kinetic energy of a stream of particles entering a system, or energy from a laser beam adds to system energy, without either being either work-done or heat-added, in the classic senses).
Where E in this general equation represents other additional advected energy terms not covered by work done on a system, or heat added to it.
Energy is also transferred from potential energy (E_p) to kinetic energy (E_k) and then back to potential energy constantly. This is referred to as conservation of energy. In this closed system, energy can not be created or destroyed, so the initial energy and the final energy will be equal to each other. This can be demonstrated by the following:
The equation can then be simplified further since E_p = mgh (mass times acceleration due to gravity times the height) and E_k = \frac{1}{2} mv^2 (half times mass times velocity squared). Then the total amount of energy can be found by adding E_p + E_k = E_{total}.
## Energy and the laws of motion
## The Hamiltonian
The total energy of a system is sometimes called the Hamiltonian, after William Rowan Hamilton. The classical equations of motion can be written in terms of the Hamiltonian, even for highly complex or abstract systems. These classical equations have remarkably direct analogs in
nonrelativistic quantum mechanics.
## The Lagrangian
Another energy-related concept is called the Lagrangian, after Joseph Louis Lagrange. This is even more fundamental than the Hamiltonian, and can be used to derive the equations of motion. In non-relativistic physics, the Lagrangian is the kinetic energy minus potential energy.
Usually, the Lagrange formalism is mathematically more convenient than the Hamiltonian for non-conservative systems (like systems with friction).
## Energy and thermodynamics
### Internal energy
Internal energy – the sum of all microscopic forms of energy of a system. It is related to the molecular structure and the degree of molecular activity and may be viewed as the sum of kinetic and potential energies of the molecules; it comprises the following types of energy:
### The laws of thermodynamics
According to the second law of thermodynamics, work can be totally converted into heat, but not vice versa.This is a mathematical consequence of statistical mechanics. The first law of thermodynamics simply asserts that energy is conserved, and that heat is included as a form of energy transfer. A commonly-used corollary of the first law is that for a "system" subject only to pressure forces and heat transfer (e.g. a cylinder-full of gas), the differential change in energy of the system (with a gain in energy signified by a positive quantity) is given by:
where the first term on the right is the heat transfer into the system, defined in terms of temperature T and entropy S (in which entropy increases and the change dS is positive when the system is heated); and the last term on the right hand side is identified as "work" done on the system, where pressure is P and volume V (the negative sign results since compressiong of the system is needed to do work on it, so that the volume change dV is negative when work is done on the system). Although this equation is the standard text-book example of energy conservation in classical thermodynamics, it is highly specific, ignoring all chemical, electric, nuclear, and gravitational forces, effects such as advection of any form of energy other than heat, and because it contains a term that depends on temperature. The most general statement of the first law — i.e. conservation of energy — is valid even in situations in which temperature is undefinable.
Energy is sometimes expressed as:
which is unsatisfactory because there cannot exist any thermodynamic state functions W or Q that are meaningful on the right hand side of this equation, except perhaps in trivial cases.
## Equipartition of energy
The energy of a mechanical harmonic oscillator (a mass on a spring) is alternatively kinetic and potential. At two points in the oscillation cycle it is entirely kinetic, and alternatively at two other points it is entirely potential. Over the whole cycle, or over many cycles net energy is thus equally split between kinetic and potential. This is called equipartition principle - total energy of a system with many degrees of freedom is equally split among all these degrees of freedom.
This principle is vitally important to understanding the behavior of a quantity closely related to energy, called entropy. Entropy is a measure of evenness of a distribution of energy between parts of a system. This concept is also related to the second law of thermodynamics which basically states that when an isolated system is given more degrees of freedom (= is given new available energy states which are the same as existing states), then energy spreads over all available degrees equally without distinction between "new" and "old" degrees.
## Oscillators, phonons, and photons
In an ensemble (connected collection) of unsynchronized oscillators, the average energy is spread equally between kinetic and potential types.
In a solid, thermal energy (often referred to loosely as heat content) can be accurately described by an ensemble of thermal phonons that act as mechanical oscillators. In this model, thermal energy is equally kinetic and potential.
In an ideal gas, the interaction potential between particles is essentially the delta function which stores no energy: thus, all of the thermal energy is kinetic.
Because an electric oscillator (LC circuit) is analogous to a mechanical oscillator, its energy must be, on average, equally kinetic and potential. It is entirely arbitrary whether the magnetic energy is considered kinetic and the electric energy considered potential, or vice versa. That is, either the inductor is analogous to the mass while the capacitor is analogous to the spring, or vice versa.
- By extension of the previous line of thought, in free space the electromagnetic field can be considered an ensemble of oscillators, meaning that radiation energy can be considered equally potential and kinetic. This model is useful, for example, when the electromagnetic Lagrangian is of primary interest and is interpreted in terms of potential and kinetic energy.
- On the other hand, in the key equation m^2 c^4 = E^2 - p^2 c^2, the contribution mc^2 is called the rest energy, and all other contributions to the energy are called kinetic energy. For a particle that has mass, this implies that the kinetic energy is 0.5 p^2/m at speeds much smaller than c, as can be proved by writing E = mc^2 √(1 + p^2 m^{-2}c^{-2}) and expanding the square root to lowest order. By this line of reasoning, the energy of a photon is entirely kinetic, because the photon is massless and has no rest energy. This expression is useful, for example, when the energy-versus-momentum relationship is of primary interest.
The two analyses are entirely consistent. The electric and magnetic degrees of freedom in item 1 are transverse to the direction of motion, while the speed in item 2 is along the direction of motion. For non-relativistic particles these two notions of potential versus kinetic energy are numerically equal, so the ambiguity is harmless, but not so for relativistic particles.
## Work and virtual work
Work is roughly force times distance. But more precisely, it is
This says that the work (W) is equal to the integral (along a certain path) of the force; for details see the mechanical work article.
Work and thus energy is frame dependent. For example, consider a ball being hit by a bat. In the center-of-mass reference frame, the bat does no work on the ball. But, in the reference frame of the person swinging the bat, considerable work is done on the ball.
## Quantum mechanics
In quantum mechanics energy is defined in terms of the energy operator
as a time derivative of the wave function. The Schrödinger equation equates energy operator to the full energy of a particle or a system. It thus can be considered as a definition of measurement of energy in quantum mechanics. The Schrödinger equation describes the space- and time-dependence of the wave function of quantum systems. The solution of this equation for bound system is discrete (a set of permitted states, each characterized by an energy level) which results in the concept of quanta. In the solution of the Schrödinger equation for any oscillator (vibrator) and for electromagnetic wave in vacuum, the resulting energy states are related to the frequency by the Planck equation E = h\nu (where h is the Planck's constant and \nu the frequency). In the case of electromagnetic wave these energy states are called quanta of light or photons.
## Relativity
When calculating kinetic energy (= work to accelerate a mass from zero speed to some finite speed) relativistically - using Lorentz transformations instead of Newtonian mechanics, Einstein discovered unexpected by-product of these calculations to be an energy term which does not vanish at zero speed. He called it rest mass energy - energy which every mass must possess even when being at rest. The amount of energy is directly proportional to the mass of body:
where
For example, consider electron-positron annihilation, in which the rest mass of individual particles is destroyed, but the inertia equivalent of the system of the two particles (its invariant mass) remains (since all energy is associated with mass), and this inertia and invariant mass is carried off by photons which individually are massless, but as a system retain their mass. This is a reversible process - the inverse process is called pair creation - in which the rest mass of particles is created from energy of two (or more) annihilating photons.
In general relativity, the stress-energy tensor serves as the source term for the gravitational field, in rough analogy to the way mass serves as the source term in the non-relativistic Newtonian approximation.
It is not uncommon to hear that energy is "equivalent" to mass. It would be more accurate to state that every energy has inertia and gravity equivalent, and because mass is a form of energy, then mass too has inertia and gravity associated with it.
# Measurement
There is no absolute measure of energy, because energy is defined as the work that one system does (or can do) on another. Thus, only of the transition of a system from one state into another can be defined and thus measured.
## Methods
The methods for the measurement of energy often deploy methods for the measurement of still more fundamental concepts of science, namely mass, distance, radiation, temperature, time, electric charge and electric current.
Conventionally the technique most often employed is calorimetry, a thermodynamic technique that relies on the measurement of temperature using a thermometer or of intensity of radiation using a bolometer.
## Units
Throughout the history of science, energy has been expressed in several different units such as ergs and calories. At present, the accepted unit of measurement for energy is the SI unit of energy, the joule.
# Forms of energy
Classical mechanics distinguishes between potential energy, which is a function of the position of an object, and kinetic energy, which is a function of its movement. Both position and movement are relative to a frame of reference, which must be specified: this is often (and originally) an arbitrary fixed point on the surface of the Earth, the terrestrial frame of reference. Some introductory authors attempt to separate all forms of energy in either kinetic or potential: this is not incorrect, but neither is it clear that it is a real simplification, as Feynman points out:
These notions of potential and kinetic energy depend on a notion of length scale. For example, one can speak of macroscopic potential and kinetic energy, which do not include thermal potential and kinetic energy. Also what is called chemical potential energy (below) is a macroscopic notion, and closer examination shows that it is really the sum of the potential and kinetic energy on the atomic and subatomic scale. Similar remarks apply to nuclear "potential" energy and most other forms of energy. This dependence on length scale is non-problematic if the various length scales are decoupled, as is often the case ... but confusion can arise when different length scales are coupled, for instance when friction converts macroscopic work into microscopic thermal energy.
## Potential energy
Potential energy, symbols Ep, V or Φ, is defined as the work done against a given force (= work of given force with minus sign) in changing the position of an object with respect to a reference position (often taken to be infinite separation). If F is the force and s is the displacement,
with the dot representing the scalar product of the two vectors.
The name "potential" energy originally signified the idea that the energy could readily be transferred as work—at least in an idealized system (reversible process, see below). This is not completely true for any real system, but is often a reasonable first approximation in classical mechanics.
The general equation above can be simplified in a number of common cases, notably when dealing with gravity or with elastic forces.
### Gravitational potential energy
The gravitational force near the Earth's surface varies very little with the height, h, and is equal to the mass, m, multiplied by the gravitational acceleration, g = 9.81 m/s². In these cases, the gravitational potential energy is given by
A more general expression for the potential energy due to Newtonian gravitation between two bodies of masses m1 and m2, useful in astronomy, is
where r is the separation between the two bodies and G is the gravitational constant,
6.6742(10)×10−11 m³kg−1s−2. In this case, the reference point is the infinite separation of the two bodies.
### Elastic potential energy
Elastic potential energy is defined as a work needed to compress (or expand) a spring.
The force, F, in a spring or any other system which obeys Hooke's law is proportional to the extension or compression, x,
where k is the force constant of the particular spring (or system). In this case, the calculated work becomes
Hooke's law is a good approximation for behaviour of chemical bonds under normal conditions, i.e. when they are not being broken or formed.
## Kinetic energy
Kinetic energy, symbols Ek, T or K, is the work required to accelerate an object to a given speed. Indeed, calculating this work one easily obtains the following:
At speeds approaching the speed of light, c, this work must be calculated using Lorentz transformations, which results in the following:
This equation reduces to the one above it, at small (compared to c) speed. A mathematical by-product of this work (which is immediately seen in the last equation) is that even at rest a mass has the amount of energy equal to:
This energy is thus called rest mass energy.
## Thermal energy
The general definition of thermal energy, symbols q or Q, is also problematic. A practical definition for small transfers of heat is
where Cv is the heat capacity of the system. This definition will fail if the system undergoes a phase transition—e.g. if ice is melting to water—as in these cases the system can absorb heat without increasing its temperature. In more complex systems, it is preferable to use the concept of internal energy rather than that of thermal energy (see Chemical energy below).
Despite the theoretical problems, the above definition is useful in the experimental measurement of energy changes. In a wide variety of situations, it is possible to use the energy released by a system to raise the temperature of another object, e.g. a bath of water. It is also possible to measure the amount of electric energy required to raise the temperature of the object by the same amount. The calorie was originally defined as the amount of energy required to raise the temperature of one gram of water by 1 °C (approximately 4.1855 J, although the definition later changed), and the British thermal unit was defined as the energy required to heat one gallon (UK) of water by 1 °F (later fixed as 1055.06 J).
## Electric energy
The electric potential energy of given configuration of charges is defined as the work which must be done against the Coulomb force to rearrange charges from infinite separation to this configuration (or the work done by the Coulomb force separating the charges from this configuration to infinity). For two point-like charges Q1 and Q2 at a distance r this work, and hence electric potential energy is equal to:
where ε0 is the electric constant of a vacuum, 107/4πc0² or 8.854188…×10−12 F/m. If the charge is accumulated in a capacitor (of capacitance C), the reference configuration is usually selected not to be infinite separation of charges, but vice versa - charges at an extremely close proximity to each other (so there is zero net charge on each plate of a capacitor). In this case the work and thus the electric potential energy becomes
If an electric current passes through a resistor, electric energy is converted to heat; if the current passes through an electric appliance, some of the electric energy will be converted into other forms of energy (although some will always be lost as heat). The amount of electric energy due to an electric current can be expressed in a number of different ways:
where U is the electric potential difference (in volts), Q is the charge (in coulombs), I is the current (in amperes), t is the time for which the current flows (in seconds), P is the power (in watts) and R is the electric resistance (in ohms). The last of these expressions is important in the practical measurement of energy, as potential difference, resistance and time can all be measured with considerable accuracy.
### Magnetic energy
There is no fundamental difference between magnetic energy and electric energy: the two phenomena are related by Maxwell's equations. The potential energy of a magnet of magnetic moment m in a magnetic field B is defined as the work of magnetic force (actually of magnetic torque) on re-alignment of the vector of the magnetic dipole moment, and is equal:
while the energy stored in a inductor (of inductance L) when current I is passing via it is
This second expression forms the basis for superconducting magnetic energy storage.
### Electromagnetic fields
Calculating work needed to create an electric or magnetic field in unit volume (say, in a capacitor or an inductor) results in the electric and magnetic fields energy densities:
and
in SI units.
Electromagnetic radiation, such as microwaves, visible light or gamma rays, represents a flow of electromagnetic energy. Applying the above expressions to magnetic and electric components of electromagnetic field both the volumetric density and the flow of energy in e/m field can be calculated. The resulting Poynting vector, which is expressed as
in SI units, gives the density of the flow of energy and its direction.
The energy of electromagnetic radiation is quantized (has discrete energy levels). The spacing between these levels is equal to
where h is the Planck constant, 6.6260693(11)×10−34 Js, and ν is the frequency of the radiation. This quantity of electromagnetic energy is usually called a photon. The photons which make up visible light have energies of 270–520 yJ, equivalent to 160–310 kJ/mol, the strength of weaker chemical bonds.
## Chemical energy
Chemical energy is the energy due to associations of atoms in molecules and various other kinds of aggregrates of matter. It may be defined as a work done by electric forces during re-arrangement of electric charges, electrons and protons, in the process of aggregration. If the chemical energy of a system decreases during a chemical reaction, it is transferred to the surroundings in some form of energy (often heat); on the other hand if the chemical energy of a system increases as a result of a chemical reaction - it is by converting another form of energy from the surroundings. For example,
It is common to quote the changes in chemical energy for one mole of the substance in question: typical values for the change in molar chemical energy during a chemical reaction range from tens to hundreds of kJ/mol.
The chemical energy as defined above is also referred to by chemists as the internal energy, U: technically, this is measured by keeping the volume of the system constant. However, most practical chemistry is performed at constant pressure and, if the volume changes during the reaction (e.g. a gas is given off), a correction must be applied to take account of the work done by or on the atmosphere to obtain the enthalpy, H:
A second correction, for the change in entropy, S, must also be performed to determine whether a chemical reaction will take place or not, giving the Gibbs free energy, G:
These corrections are sometimes negligible, but often not (especially in reactions involving gases).
Since the industrial revolution, the burning of coal, oil, natural gas or products derived from them has been a socially significant transformation of chemical energy into other forms of energy. the energy "consumption" (one should really speak of "energy transformation") of a society or country is often quoted in reference to the average energy released by the combustion of these fossil fuels:
On the same basis, a tank-full of gasoline (45 litres, 12 gallons) is equivalent to about 1.6 GJ of chemical energy. Another chemically-based unit of measurement for energy is the "tonne of TNT", taken as 4.184 GJ. Hence, burning a tonne of oil releases about ten times as much energy as the explosion of one tonne of TNT: fortunately, the energy is usually released in a slower, more controlled manner.
Simple examples of chemical energy are batteries and food. When you eat the food is digested and turned into chemical energy which can be transformed to kinetic energy.
## Nuclear energy
Nuclear potential energy, along with electric potential energy, provides the energy released from nuclear fission and nuclear fusion processes. The result of both these processes are nuclei in which strong nuclear forces bind nuclear particles more strongly and closely. Weak nuclear forces (different from strong forces) provide the potential energy for certain kinds of radioactive decay, such as beta decay. The energy released in nuclear processes is so large that the relativistic change in mass (after the energy has been removed) can be as much as several parts per thousand.
Nuclear particles (nucleons) like protons and neutrons are not destroyed (law of conservation of baryon number) in fission and fusion processes. A few lighter particles may be created or destroyed (example: beta minus and beta plus decay, or electron capture decay), but these minor processes are not important to the immediate energy release in fission and fusion. Rather, fission and fusion release energy when collections of baryons become more tightly bound, and it is the energy associated with a fraction of the mass of the nucleons (but not the whole particles) which appears as the heat and electromagnetic radiation generated by nuclear reactions. This heat and radiation retains the "missing" mass, but the mass is missing only because it escapes in the form of heat and light, which retain the mass and conduct it out of the system where it is not measured. The energy from the Sun, also called solar energy, is an example of this form of energy conversion. In the Sun, the process of hydrogen fusion converts about 4 million metric tons of solar matter per second into light, which is radiated into space, but during this process, the number of total protons and neutrons in the sun does not change. In this system, the light itself retains the inertial equivalent of this mass, and indeed the mass itself (as a system), which represents 4 million tons per second of electromagnetic radiation, moving into space. Each of the helium nuclei which are formed in the process are less massive than the four protons from they were formed, but (to a good approximation), no particles or atoms are destroyed in the process of turning the sun's nuclear potential energy into light.
## Surface energy
If there is any kind of tension in a surface, such as a stretched sheet of rubber or material interfaces, it is possible to define surface energy. In particular, any meeting of dissimilar materials that don't mix will result in some kind of surface tension, if there is freedom for the surfaces to move then, as seen in capillary surfaces for example, the minimum energy will as usual be sought.
A minimal surface, for example, represents the smallest possible energy that a surface can have if its energy is proportional to the area of the surface. For this reason, (open) soap films of small size are minimal surfaces (small size reduces gravity effects, and openness prevents pressure from building up. Note that a bubble is a minimum energy surface but not a minimal surface by definition).
# Transformations of energy
One form of energy can often be readily transformed into another with the help of a device- for instance, a battery, from chemical energy to electric energy; a dam: gravitational potential energy to kinetic energy of moving water (and the blades of a turbine) and ultimately to electric energy through an electric generator. Similarly, in the case of a chemical explosion, chemical potential energy is transformed to kinetic energy and thermal energy in a very short time. Yet another example is that of a pendulum. At its highest points the kinetic energy is zero and the gravitational potential energy is at maximum. At its lowest point the kinetic energy is at maximum and is equal to the decrease of potential energy. If one (unrealistically) assumes that there is no friction, the conversion of energy between these processes is perfect, and the pendulum will continue swinging forever.
Energy can be converted into matter and vice versa. The mass-energy equivalence formula E = mc², derived independently by Albert Einstein and Henri Poincaré, quantifies the relationship between mass and rest energy. Since c^2 is extremely large relative to ordinary human scales, the conversion of mass to other forms of energy can liberate tremendous amounts of energy, as can be seen in nuclear reactors and nuclear weapons. Conversely, the mass equivalent of a unit of energy is minuscule, which is why a loss of energy from most systems is difficult to measure by weight, unless the energy loss is very large. Examples of energy transformation into matter (particles) are found in high energy nuclear physics.
In nature, transformations of energy can be fundamentally classed into two kinds: those that are thermodynamically reversible, and those that are thermodynamically irreversible. A reversible process in thermodynamics is one in which no energy is dissipated into empty quantum states available in a volume, from which it cannot be recovered into more concentrated forms (fewer quantum states), without degradation of even more energy. A reversible process is one in which this sort of dissipation does not happen. For example, conversion of energy from one type of potential field to another, is reversible, as in the pendulum system described above. In processes where heat is generated, however, quantum states of lower energy, present as possible exitations in fields between atoms, act as a reservoir for part of the energy, from which it cannot be recovered, in order to be converted with 100% efficiency into other forms of energy. In this case, the energy must partly stay as heat, and cannot be completely recovered as usable energy, except at the price of an increase in some other kind of heat-like increase in disorder in quantum states, in the universe (such as an expansion of matter, or a randomization in a crystal).
As the universe evolves in time, more and more of its energy becomes trapped in irreversible states (i.e., as heat or other kinds of increases in disorder). This has been referred to as the inevitable thermodynamic heat death of the universe. In this heat death the energy of the universe does not change, but the fraction of energy which is available to do work, or be transformed to other usable forms of energy, grows less and less.
# Law of conservation of energy
Energy is subject to the law of conservation of energy. According to this law, energy can neither be created (produced) nor destroyed itself. It can only be transformed.
Most kinds of energy (with gravitational energy being a notable exception) are also subject to strict local conservation laws, as well. In this case, energy can only be exchanged between adjacent regions of space, and all observers agree as to the volumetric density of energy in any given space. There is also a global law of conservation of energy, stating that the total energy of the universe cannot change; this is a corollary of the local law, but not vice versa. Conservation of energy is the mathematical consequence of translational symmetry of time (that is, the indistinguishability of time intervals taken at different time) - see Noether's theorem.
According to energy conservation law the total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system.
This law is a fundamental principle of physics. It follows from the translational symmetry of time, a property of most phenomena below the cosmic scale that makes them independent of their locations on the time coordinate. Put differently, yesterday, today, and tomorrow are physically indistinguishable.
Because energy is quantity which is canonical conjugate to time, it is impossible to define exact amount of energy during any definite time interval - making it impossible to apply the law of conservation of energy. This must not be considered a "violation" of the law. We know the law still holds, because a succession of short time periods does not accumulate any violation of conservation of energy.
In quantum mechanics energy is expressed using the Hamiltonian operator. On
any time scales, the uncertainty in the energy is by
which is similar in form to the uncertainty principle (but not really mathematically equivalent thereto, since H and t are not dynamically conjugate variables, neither in classical nor in quantum mechanics).
In particle physics, this inequality permits a qualitative understanding of virtual particles which carry momentum, exchange by which with real particles is responsible for creation of all known fundamental forces (more accurately known as fundamental interactions). Virtual photons (which are simply lowest quantum mechanical energy state of photons) are also responsible for electrostatic interaction between electric charges (which results in Coulomb law), for spontaneous radiative decay of exited atomic and nuclear states, for the Casimir force, for van der Waals bond forces and some other observable phenomena.
# Energy and life
Any living organism relies on an external source of energy—radiation from the Sun in the case of green plants; chemical energy in some form in the case of animals—to be able to grow and reproduce. The daily 1500–2000 Calories (6–8 MJ) recommended for a human adult are taken as a combination of oxygen and food molecules, the latter mostly carbohydrates and fats, of which glucose (C6H12O6) and stearin (C57H110O6) are convenient examples. The food molecules are oxidised to carbon dioxide and water in the mitochondria
and some of the energy is used to convert ADP into ATP
The rest of the chemical energy in the carbohydrate or fat is converted into heat: the ATP is used as a sort of "energy currency", and some of the chemical energy it contains when split and reacted with water, is used for other metabolism (at each stage of a metabolic pathway, some chemical energy is converted into heat). Only a tiny fraction of the original chemical energy is used for work:
It would appear that living organisms are remarkably inefficient (in the physical sense) in their use of the energy they receive (chemical energy or radiation), and it is true that most real machines manage higher efficiencies. However, in growing organisms the energy that is converted to heat serves a vital purpose, as it allows the organism tissue to be highly ordered with regard to the molecules it is built from. The second law of thermodynamics states that energy (and matter) tends to become more evenly spread out across the universe: to concentrate energy (or matter) in one specific place, it is necessary to spread out a greater amount of energy (as heat) across the remainder of the universe ("the surroundings"). Simpler organisms can achieve higher energy efficiencies than more complex ones, but the complex organisms can occupy ecological niches that are not available to their simpler brethren. The conversion of a portion of the chemical energy to heat at each step in a metabolic pathway is the physical reason behind the pyramid of biomass observed in ecology: to take just the first step in the food chain, of the estimated 124.7 Pg/a of carbon that is fixed by photosynthesis, 64.3 Pg/a (52%) are used for the metabolism of green plants, i.e. reconverted into carbon dioxide and heat. | Energy
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In physics and other sciences, energy (from the Greek ενεργός, energos, "active, working")[1] is a scalar physical quantity that is a property of objects and systems which is conserved by nature. Energy is often defined as the ability to do work.
Several different forms of energy, such as kinetic, potential, thermal, chemical, nuclear, and mass have been defined to explain all known natural phenomena.
Energy is converted from one form to another, but it is never created or destroyed. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.[2]
Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but nonzero kinetic energy relative to the earth.
# History
The concept of energy emerged out of the idea of vis viva, which Leibniz defined as the product of the mass of an object and its velocity squared; he believed that total vis viva was conserved. To account for slowing due to friction, Leibniz claimed that heat consisted of the random motion of the constituent parts of matter — a view shared by Isaac Newton, although it would be more than a century until this was generally accepted. In 1807, Thomas Young was the first to use the term "energy", instead of vis viva, in its modern sense.[3] Gustave-Gaspard Coriolis described "kinetic energy" in 1829 in its modern sense, and in 1853, William Rankine coined the term "potential energy."
It was argued for some years whether energy was a substance (the caloric) or merely a physical quantity, such as momentum.
He amalgamated all of these laws into the laws of thermodynamics, which aided in the rapid development of explanations of chemical processes using the concept of energy by Rudolf Clausius, Josiah Willard Gibbs and Walther Nernst. It also led to a mathematical formulation of the concept of entropy by Clausius, and to the introduction of laws of radiant energy by Jožef Stefan.
During a 1961 lecture[4] for undergraduate students at the California Institute of Technology, Richard Feynman, a celebrated physics teacher and Nobel Laureate, said this about the concept of energy:
Since 1918 it has been known that the law of conservation of energy is the direct mathematical consequence of the translational symmetry of the quantity conjugate to energy, namely time. That is, energy is conserved because the laws of physics do not distinguish between different moments of time (see Noether's theorem).
# Energy in various contexts since the beginning of the universe
The concept of energy and its transformations is extremely useful in explaining and predicting most natural phenomena. The direction of transformations in energy (what kind of energy is transformed to what other kind) is often described by entropy (equal energy spread among all available degrees of freedom) considerations, since in practice all energy transformations are permitted on a small scale, but certain larger transformations are not permitted because it is statistically unlikely that energy or matter will randomly move into more concentrated forms or smaller spaces.
The concept of energy is used often in all fields of science.
Energy transformations in the universe over time are characterized by various kinds of potential energy which has been available since the Big Bang, later being "released" (transformed to more active types of energy such as kinetic or radiant energy), when a triggering mechanism is available. Familiar examples of such processes include nuclear decay, in which energy is released which was originally "stored" in heavy isotopes (such as uranium and thorium), using the gravitational potential energy released from the gravitational collapse of supernovae, which created these elements before they were incorporated into the solar system and the Earth. Heat from such nuclear decay in the core of the Earth releases heat, which in turn may lift mountains via orogenesis. This lifting represents a kind of gravitational potential energy storage, which may be released to active kinetic energy in landslides, after a triggering event. Earthquakes also release stored elastic potential energy in rocks, a store which has been produced ultimately from the same heat sources. Thus, according to present understanding, familiar events such as landslides and earthquakes release energy stored since the collapse of long-destroyed stars.
In another similar chain of transformations from the dawn of the universe, nuclear fussion of hydrogen in the Sun releases potential energy stored at the time of the Big Bang, when according to theory, space expanded and the universe cooled too rapidly for hydrogen to completely fuse into heavier elements. Energy from this fusion process is triggered by heat and pressure generated from gravitational collapse of hydrogen clouds when they produce stars, and some of the energy is transformed to sunlight. Such sunlight from our Sun may again be stored as gravitational potential energy after it strikes the Earth, when (for example) water evaporates from oceans and is deposited upon mountains (where, after being released at a hydroelectric dam, it can be used to drive turbine/generators to produce electricity). Sunlight also drives all weather phenomenon, including violent events triggered when large unstable areas of warm ocean, heated over months, give up some of their thermal energy suddently to power a few days of hurricanes. Sunlight is also is captured by plants as chemical potential energy, when carbon dioxide and water are converted into carbohydrates, lipids, and oxygen. This energy may be triggered suddenly by a spark in a forest fire; or may be available more slowly for animal or human metabolism, when these molecules are ingested, and catabolism is triggered by enzyme action. Through all of these tranformation chains, potential energy stored at the time of the Big Bang is later released by intermediate events, sometimes being stored in a number of ways over time between releases as more active energy. In all these events, one kind of energy is converted to other types of energy, including heat.
# Regarding applications of the concept of energy
Energy is subject to a strict global conservation law; that is, whenever one measures (or calculates) the total energy of a system of particles whose interactions do not depend explicitly on time, it is found that the total energy of the system always remains constant.[6]
- The total energy of a system can be subdivided and classified in various ways. For example, it is sometimes convenient to distinguish potential energy (which is a function of coordinates only) from kinetic energy (which is a function of coordinate time derivatives only). It may also be convenient to distinguish gravitational energy, electric energy, thermal energy, and other forms. These classifications overlap; for instance thermal energy usually consists partly of kinetic and partly of potential energy.
- The transfer of energy can take various forms; familiar examples include work, heat flow, and advection, as discussed below.
- The word "energy" is also used outside of physics in many ways, which can lead to ambiguity and inconsistency. The vernacular terminology is not consistent with technical terminology. For example, the important public-service announcement, "Please conserve energy" uses vernacular notions of "conservation" and "energy" which make sense in their own context but are utterly incompatible with the technical notions of "conservation" and "energy" (such as are used in the law of conservation of energy).[7]
In classical physics energy is considered a scalar quantity, the canonical conjugate to time. In special relativity energy is also a scalar (although not a Lorentz scalar but a time component of the energy-momentum 4-vector).[8] In other words, energy is invariant with respect to rotations of space, but not invariant with respect to rotations of space-time (= boosts).
## Energy transfer
Because energy is strictly conserved and is also locally conserved (wherever it can be defined), it is important to remember that by definition of energy the transfer of energy between the "system" and adjacent regions is work. A familiar example is mechanical work. In simple cases this is written as:
if there are no other energy-transfer processes involved. Here <math>\Delta{}E</math> is the amount of energy transferred, and <math>W</math> represents the work done on the system.
More generally, the energy transfer can be split into two categories:
where <math>Q</math> represents the heat flow into the system.
There are other ways in which an open system can gain or lose energy. If mass is counted as energy (as in many relativistic problems) then <math>E</math> must contain a term for mass lost or gained. In chemical systems, energy can be added to a system by means of adding substances with different chemical potentials, which potentials are then extracted (both of these process are illustrated by fueling an auto, a system which gains in energy thereby, without addition of either work or heat). These terms may be added to the above equation, or they can generally be subsumed into a quantity called "energy addition term <math>E</math>" which refers to any type of energy carried over the surface of a control volume or system volume. Examples may be seen above, and many others can be imagined (for example, the kinetic energy of a stream of particles entering a system, or energy from a laser beam adds to system energy, without either being either work-done or heat-added, in the classic senses).
Where E in this general equation represents other additional advected energy terms not covered by work done on a system, or heat added to it.
Energy is also transferred from potential energy (<math>E_p</math>) to kinetic energy (<math>E_k</math>) and then back to potential energy constantly. This is referred to as conservation of energy. In this closed system, energy can not be created or destroyed, so the initial energy and the final energy will be equal to each other. This can be demonstrated by the following:
The equation can then be simplified further since <math>E_p = mgh</math> (mass times acceleration due to gravity times the height) and <math>E_k = \frac{1}{2} mv^2</math> (half times mass times velocity squared). Then the total amount of energy can be found by adding <math>E_p + E_k = E_{total}</math>.
## Energy and the laws of motion
## The Hamiltonian
The total energy of a system is sometimes called the Hamiltonian, after William Rowan Hamilton. The classical equations of motion can be written in terms of the Hamiltonian, even for highly complex or abstract systems. These classical equations have remarkably direct analogs in
nonrelativistic quantum mechanics.[9]
## The Lagrangian
Another energy-related concept is called the Lagrangian, after Joseph Louis Lagrange. This is even more fundamental than the Hamiltonian, and can be used to derive the equations of motion. In non-relativistic physics, the Lagrangian is the kinetic energy minus potential energy.
Usually, the Lagrange formalism is mathematically more convenient than the Hamiltonian for non-conservative systems (like systems with friction).
## Energy and thermodynamics
### Internal energy
Internal energy – the sum of all microscopic forms of energy of a system. It is related to the molecular structure and the degree of molecular activity and may be viewed as the sum of kinetic and potential energies of the molecules; it comprises the following types of energy:[10]
### The laws of thermodynamics
According to the second law of thermodynamics, work can be totally converted into heat, but not vice versa.This is a mathematical consequence of statistical mechanics. The first law of thermodynamics simply asserts that energy is conserved,[11] and that heat is included as a form of energy transfer. A commonly-used corollary of the first law is that for a "system" subject only to pressure forces and heat transfer (e.g. a cylinder-full of gas), the differential change in energy of the system (with a gain in energy signified by a positive quantity) is given by:
where the first term on the right is the heat transfer into the system, defined in terms of temperature T and entropy S (in which entropy increases and the change dS is positive when the system is heated); and the last term on the right hand side is identified as "work" done on the system, where pressure is P and volume V (the negative sign results since compressiong of the system is needed to do work on it, so that the volume change dV is negative when work is done on the system). Although this equation is the standard text-book example of energy conservation in classical thermodynamics, it is highly specific, ignoring all chemical, electric, nuclear, and gravitational forces, effects such as advection of any form of energy other than heat, and because it contains a term that depends on temperature. The most general statement of the first law — i.e. conservation of energy — is valid even in situations in which temperature is undefinable.
Energy is sometimes expressed as:
which is unsatisfactory[7] because there cannot exist any thermodynamic state functions W or Q that are meaningful on the right hand side of this equation, except perhaps in trivial cases.
## Equipartition of energy
The energy of a mechanical harmonic oscillator (a mass on a spring) is alternatively kinetic and potential. At two points in the oscillation cycle it is entirely kinetic, and alternatively at two other points it is entirely potential. Over the whole cycle, or over many cycles net energy is thus equally split between kinetic and potential. This is called equipartition principle - total energy of a system with many degrees of freedom is equally split among all these degrees of freedom.
This principle is vitally important to understanding the behavior of a quantity closely related to energy, called entropy. Entropy is a measure of evenness of a distribution of energy between parts of a system. This concept is also related to the second law of thermodynamics which basically states that when an isolated system is given more degrees of freedom (= is given new available energy states which are the same as existing states), then energy spreads over all available degrees equally without distinction between "new" and "old" degrees.
## Oscillators, phonons, and photons
In an ensemble (connected collection) of unsynchronized oscillators, the average energy is spread equally between kinetic and potential types.
In a solid, thermal energy (often referred to loosely as heat content) can be accurately described by an ensemble of thermal phonons that act as mechanical oscillators. In this model, thermal energy is equally kinetic and potential.
In an ideal gas, the interaction potential between particles is essentially the delta function which stores no energy: thus, all of the thermal energy is kinetic.
Because an electric oscillator (LC circuit) is analogous to a mechanical oscillator, its energy must be, on average, equally kinetic and potential. It is entirely arbitrary whether the magnetic energy is considered kinetic and the electric energy considered potential, or vice versa. That is, either the inductor is analogous to the mass while the capacitor is analogous to the spring, or vice versa.
- By extension of the previous line of thought, in free space the electromagnetic field can be considered an ensemble of oscillators, meaning that radiation energy can be considered equally potential and kinetic. This model is useful, for example, when the electromagnetic Lagrangian is of primary interest and is interpreted in terms of potential and kinetic energy.
- On the other hand, in the key equation <math>m^2 c^4 = E^2 - p^2 c^2</math>, the contribution <math>mc^2</math> is called the rest energy, and all other contributions to the energy are called kinetic energy. For a particle that has mass, this implies that the kinetic energy is <math>0.5 p^2/m</math> at speeds much smaller than c, as can be proved by writing <math>E = mc^2 </math> √<math>(1 + p^2 m^{-2}c^{-2})</math> and expanding the square root to lowest order. By this line of reasoning, the energy of a photon is entirely kinetic, because the photon is massless and has no rest energy. This expression is useful, for example, when the energy-versus-momentum relationship is of primary interest.
The two analyses are entirely consistent. The electric and magnetic degrees of freedom in item 1 are transverse to the direction of motion, while the speed in item 2 is along the direction of motion. For non-relativistic particles these two notions of potential versus kinetic energy are numerically equal, so the ambiguity is harmless, but not so for relativistic particles.
## Work and virtual work
Work is roughly force times distance. But more precisely, it is
This says that the work (<math>W</math>) is equal to the integral (along a certain path) of the force; for details see the mechanical work article.
Work and thus energy is frame dependent. For example, consider a ball being hit by a bat. In the center-of-mass reference frame, the bat does no work on the ball. But, in the reference frame of the person swinging the bat, considerable work is done on the ball.
## Quantum mechanics
In quantum mechanics energy is defined in terms of the energy operator
as a time derivative of the wave function. The Schrödinger equation equates energy operator to the full energy of a particle or a system. It thus can be considered as a definition of measurement of energy in quantum mechanics. The Schrödinger equation describes the space- and time-dependence of the wave function of quantum systems. The solution of this equation for bound system is discrete (a set of permitted states, each characterized by an energy level) which results in the concept of quanta. In the solution of the Schrödinger equation for any oscillator (vibrator) and for electromagnetic wave in vacuum, the resulting energy states are related to the frequency by the Planck equation <math>E = h\nu</math> (where <math>h</math> is the Planck's constant and <math>\nu</math> the frequency). In the case of electromagnetic wave these energy states are called quanta of light or photons.
## Relativity
When calculating kinetic energy (= work to accelerate a mass from zero speed to some finite speed) relativistically - using Lorentz transformations instead of Newtonian mechanics, Einstein discovered unexpected by-product of these calculations to be an energy term which does not vanish at zero speed. He called it rest mass energy - energy which every mass must possess even when being at rest. The amount of energy is directly proportional to the mass of body:
where
For example, consider electron-positron annihilation, in which the rest mass of individual particles is destroyed, but the inertia equivalent of the system of the two particles (its invariant mass) remains (since all energy is associated with mass), and this inertia and invariant mass is carried off by photons which individually are massless, but as a system retain their mass. This is a reversible process - the inverse process is called pair creation - in which the rest mass of particles is created from energy of two (or more) annihilating photons.
In general relativity, the stress-energy tensor serves as the source term for the gravitational field, in rough analogy to the way mass serves as the source term in the non-relativistic Newtonian approximation.[8]
It is not uncommon to hear that energy is "equivalent" to mass. It would be more accurate to state that every energy has inertia and gravity equivalent, and because mass is a form of energy, then mass too has inertia and gravity associated with it.
# Measurement
There is no absolute measure of energy, because energy is defined as the work that one system does (or can do) on another. Thus, only of the transition of a system from one state into another can be defined and thus measured.
## Methods
The methods for the measurement of energy often deploy methods for the measurement of still more fundamental concepts of science, namely mass, distance, radiation, temperature, time, electric charge and electric current.
Conventionally the technique most often employed is calorimetry, a thermodynamic technique that relies on the measurement of temperature using a thermometer or of intensity of radiation using a bolometer.
## Units
Throughout the history of science, energy has been expressed in several different units such as ergs and calories. At present, the accepted unit of measurement for energy is the SI unit of energy, the joule.
# Forms of energy
Classical mechanics distinguishes between potential energy, which is a function of the position of an object, and kinetic energy, which is a function of its movement. Both position and movement are relative to a frame of reference, which must be specified: this is often (and originally) an arbitrary fixed point on the surface of the Earth, the terrestrial frame of reference. Some introductory authors[citation needed] attempt to separate all forms of energy in either kinetic or potential: this is not incorrect, but neither is it clear that it is a real simplification, as Feynman points out:
These notions of potential and kinetic energy depend on a notion of length scale. For example, one can speak of macroscopic potential and kinetic energy, which do not include thermal potential and kinetic energy. Also what is called chemical potential energy (below) is a macroscopic notion, and closer examination shows that it is really the sum of the potential and kinetic energy on the atomic and subatomic scale. Similar remarks apply to nuclear "potential" energy and most other forms of energy. This dependence on length scale is non-problematic if the various length scales are decoupled, as is often the case ... but confusion can arise when different length scales are coupled, for instance when friction converts macroscopic work into microscopic thermal energy.
## Potential energy
Potential energy, symbols Ep, V or Φ, is defined as the work done against a given force (= work of given force with minus sign) in changing the position of an object with respect to a reference position (often taken to be infinite separation). If F is the force and s is the displacement,
with the dot representing the scalar product of the two vectors.
The name "potential" energy originally signified the idea that the energy could readily be transferred as work—at least in an idealized system (reversible process, see below). This is not completely true for any real system, but is often a reasonable first approximation in classical mechanics.
The general equation above can be simplified in a number of common cases, notably when dealing with gravity or with elastic forces.
### Gravitational potential energy
The gravitational force near the Earth's surface varies very little with the height, h, and is equal to the mass, m, multiplied by the gravitational acceleration, g = 9.81 m/s². In these cases, the gravitational potential energy is given by
A more general expression for the potential energy due to Newtonian gravitation between two bodies of masses m1 and m2, useful in astronomy, is
where r is the separation between the two bodies and G is the gravitational constant,
6.6742(10)×10−11 m³kg−1s−2.[12] In this case, the reference point is the infinite separation of the two bodies.
### Elastic potential energy
Elastic potential energy is defined as a work needed to compress (or expand) a spring.
The force, F, in a spring or any other system which obeys Hooke's law is proportional to the extension or compression, x,
where k is the force constant of the particular spring (or system). In this case, the calculated work becomes
Hooke's law is a good approximation for behaviour of chemical bonds under normal conditions, i.e. when they are not being broken or formed.
## Kinetic energy
Kinetic energy, symbols Ek, T or K, is the work required to accelerate an object to a given speed. Indeed, calculating this work one easily obtains the following:
At speeds approaching the speed of light, c, this work must be calculated using Lorentz transformations, which results in the following:
This equation reduces to the one above it, at small (compared to c) speed. A mathematical by-product of this work (which is immediately seen in the last equation) is that even at rest a mass has the amount of energy equal to:
This energy is thus called rest mass energy.
## Thermal energy
The general definition of thermal energy, symbols q or Q, is also problematic. A practical definition for small transfers of heat is
where Cv is the heat capacity of the system. This definition will fail if the system undergoes a phase transition—e.g. if ice is melting to water—as in these cases the system can absorb heat without increasing its temperature. In more complex systems, it is preferable to use the concept of internal energy rather than that of thermal energy (see Chemical energy below).
Despite the theoretical problems, the above definition is useful in the experimental measurement of energy changes. In a wide variety of situations, it is possible to use the energy released by a system to raise the temperature of another object, e.g. a bath of water. It is also possible to measure the amount of electric energy required to raise the temperature of the object by the same amount. The calorie was originally defined as the amount of energy required to raise the temperature of one gram of water by 1 °C (approximately 4.1855 J, although the definition later changed), and the British thermal unit was defined as the energy required to heat one gallon (UK) of water by 1 °F (later fixed as 1055.06 J).
## Electric energy
The electric potential energy of given configuration of charges is defined as the work which must be done against the Coulomb force to rearrange charges from infinite separation to this configuration (or the work done by the Coulomb force separating the charges from this configuration to infinity). For two point-like charges Q1 and Q2 at a distance r this work, and hence electric potential energy is equal to:
where ε0 is the electric constant of a vacuum, 107/4πc0² or 8.854188…×10−12 F/m.[12] If the charge is accumulated in a capacitor (of capacitance C), the reference configuration is usually selected not to be infinite separation of charges, but vice versa - charges at an extremely close proximity to each other (so there is zero net charge on each plate of a capacitor). In this case the work and thus the electric potential energy becomes
If an electric current passes through a resistor, electric energy is converted to heat; if the current passes through an electric appliance, some of the electric energy will be converted into other forms of energy (although some will always be lost as heat). The amount of electric energy due to an electric current can be expressed in a number of different ways:
where U is the electric potential difference (in volts), Q is the charge (in coulombs), I is the current (in amperes), t is the time for which the current flows (in seconds), P is the power (in watts) and R is the electric resistance (in ohms). The last of these expressions is important in the practical measurement of energy, as potential difference, resistance and time can all be measured with considerable accuracy.
### Magnetic energy
There is no fundamental difference between magnetic energy and electric energy: the two phenomena are related by Maxwell's equations. The potential energy of a magnet of magnetic moment m in a magnetic field B is defined as the work of magnetic force (actually of magnetic torque) on re-alignment of the vector of the magnetic dipole moment, and is equal:
while the energy stored in a inductor (of inductance L) when current I is passing via it is
This second expression forms the basis for superconducting magnetic energy storage.
### Electromagnetic fields
Calculating work needed to create an electric or magnetic field in unit volume (say, in a capacitor or an inductor) results in the electric and magnetic fields energy densities:
and
in SI units.
Electromagnetic radiation, such as microwaves, visible light or gamma rays, represents a flow of electromagnetic energy. Applying the above expressions to magnetic and electric components of electromagnetic field both the volumetric density and the flow of energy in e/m field can be calculated. The resulting Poynting vector, which is expressed as
in SI units, gives the density of the flow of energy and its direction.
The energy of electromagnetic radiation is quantized (has discrete energy levels). The spacing between these levels is equal to
where h is the Planck constant, 6.6260693(11)×10−34 Js,[12] and ν is the frequency of the radiation. This quantity of electromagnetic energy is usually called a photon. The photons which make up visible light have energies of 270–520 yJ, equivalent to 160–310 kJ/mol, the strength of weaker chemical bonds.
## Chemical energy
Chemical energy is the energy due to associations of atoms in molecules and various other kinds of aggregrates of matter. It may be defined as a work done by electric forces during re-arrangement of electric charges, electrons and protons, in the process of aggregration. If the chemical energy of a system decreases during a chemical reaction, it is transferred to the surroundings in some form of energy (often heat); on the other hand if the chemical energy of a system increases as a result of a chemical reaction - it is by converting another form of energy from the surroundings. For example,
It is common to quote the changes in chemical energy for one mole of the substance in question: typical values for the change in molar chemical energy during a chemical reaction range from tens to hundreds of kJ/mol.
The chemical energy as defined above is also referred to by chemists as the internal energy, U: technically, this is measured by keeping the volume of the system constant. However, most practical chemistry is performed at constant pressure and, if the volume changes during the reaction (e.g. a gas is given off), a correction must be applied to take account of the work done by or on the atmosphere to obtain the enthalpy, H:
A second correction, for the change in entropy, S, must also be performed to determine whether a chemical reaction will take place or not, giving the Gibbs free energy, G:
These corrections are sometimes negligible, but often not (especially in reactions involving gases).
Since the industrial revolution, the burning of coal, oil, natural gas or products derived from them has been a socially significant transformation of chemical energy into other forms of energy. the energy "consumption" (one should really speak of "energy transformation") of a society or country is often quoted in reference to the average energy released by the combustion of these fossil fuels:
On the same basis, a tank-full of gasoline (45 litres, 12 gallons) is equivalent to about 1.6 GJ of chemical energy. Another chemically-based unit of measurement for energy is the "tonne of TNT", taken as 4.184 GJ. Hence, burning a tonne of oil releases about ten times as much energy as the explosion of one tonne of TNT: fortunately, the energy is usually released in a slower, more controlled manner.
Simple examples of chemical energy are batteries and food. When you eat the food is digested and turned into chemical energy which can be transformed to kinetic energy.
## Nuclear energy
Nuclear potential energy, along with electric potential energy, provides the energy released from nuclear fission and nuclear fusion processes. The result of both these processes are nuclei in which strong nuclear forces bind nuclear particles more strongly and closely. Weak nuclear forces (different from strong forces) provide the potential energy for certain kinds of radioactive decay, such as beta decay. The energy released in nuclear processes is so large that the relativistic change in mass (after the energy has been removed) can be as much as several parts per thousand.
Nuclear particles (nucleons) like protons and neutrons are not destroyed (law of conservation of baryon number) in fission and fusion processes. A few lighter particles may be created or destroyed (example: beta minus and beta plus decay, or electron capture decay), but these minor processes are not important to the immediate energy release in fission and fusion. Rather, fission and fusion release energy when collections of baryons become more tightly bound, and it is the energy associated with a fraction of the mass of the nucleons (but not the whole particles) which appears as the heat and electromagnetic radiation generated by nuclear reactions. This heat and radiation retains the "missing" mass, but the mass is missing only because it escapes in the form of heat and light, which retain the mass and conduct it out of the system where it is not measured. The energy from the Sun, also called solar energy, is an example of this form of energy conversion. In the Sun, the process of hydrogen fusion converts about 4 million metric tons of solar matter per second into light, which is radiated into space, but during this process, the number of total protons and neutrons in the sun does not change. In this system, the light itself retains the inertial equivalent of this mass, and indeed the mass itself (as a system), which represents 4 million tons per second of electromagnetic radiation, moving into space. Each of the helium nuclei which are formed in the process are less massive than the four protons from they were formed, but (to a good approximation), no particles or atoms are destroyed in the process of turning the sun's nuclear potential energy into light.
## Surface energy
If there is any kind of tension in a surface, such as a stretched sheet of rubber or material interfaces, it is possible to define surface energy. In particular, any meeting of dissimilar materials that don't mix will result in some kind of surface tension, if there is freedom for the surfaces to move then, as seen in capillary surfaces for example, the minimum energy will as usual be sought.
A minimal surface, for example, represents the smallest possible energy that a surface can have if its energy is proportional to the area of the surface. For this reason, (open) soap films of small size are minimal surfaces (small size reduces gravity effects, and openness prevents pressure from building up. Note that a bubble is a minimum energy surface but not a minimal surface by definition).
# Transformations of energy
One form of energy can often be readily transformed into another with the help of a device- for instance, a battery, from chemical energy to electric energy; a dam: gravitational potential energy to kinetic energy of moving water (and the blades of a turbine) and ultimately to electric energy through an electric generator. Similarly, in the case of a chemical explosion, chemical potential energy is transformed to kinetic energy and thermal energy in a very short time. Yet another example is that of a pendulum. At its highest points the kinetic energy is zero and the gravitational potential energy is at maximum. At its lowest point the kinetic energy is at maximum and is equal to the decrease of potential energy. If one (unrealistically) assumes that there is no friction, the conversion of energy between these processes is perfect, and the pendulum will continue swinging forever.
Energy can be converted into matter and vice versa. The mass-energy equivalence formula E = mc², derived independently by Albert Einstein and Henri Poincaré,[citation needed] quantifies the relationship between mass and rest energy. Since <math>c^2</math> is extremely large relative to ordinary human scales, the conversion of mass to other forms of energy can liberate tremendous amounts of energy, as can be seen in nuclear reactors and nuclear weapons. Conversely, the mass equivalent of a unit of energy is minuscule, which is why a loss of energy from most systems is difficult to measure by weight, unless the energy loss is very large. Examples of energy transformation into matter (particles) are found in high energy nuclear physics.
In nature, transformations of energy can be fundamentally classed into two kinds: those that are thermodynamically reversible, and those that are thermodynamically irreversible. A reversible process in thermodynamics is one in which no energy is dissipated into empty quantum states available in a volume, from which it cannot be recovered into more concentrated forms (fewer quantum states), without degradation of even more energy. A reversible process is one in which this sort of dissipation does not happen. For example, conversion of energy from one type of potential field to another, is reversible, as in the pendulum system described above. In processes where heat is generated, however, quantum states of lower energy, present as possible exitations in fields between atoms, act as a reservoir for part of the energy, from which it cannot be recovered, in order to be converted with 100% efficiency into other forms of energy. In this case, the energy must partly stay as heat, and cannot be completely recovered as usable energy, except at the price of an increase in some other kind of heat-like increase in disorder in quantum states, in the universe (such as an expansion of matter, or a randomization in a crystal).
As the universe evolves in time, more and more of its energy becomes trapped in irreversible states (i.e., as heat or other kinds of increases in disorder). This has been referred to as the inevitable thermodynamic heat death of the universe. In this heat death the energy of the universe does not change, but the fraction of energy which is available to do work, or be transformed to other usable forms of energy, grows less and less.
# Law of conservation of energy
Energy is subject to the law of conservation of energy. According to this law, energy can neither be created (produced) nor destroyed itself. It can only be transformed.
Most kinds of energy (with gravitational energy being a notable exception)[1] are also subject to strict local conservation laws, as well. In this case, energy can only be exchanged between adjacent regions of space, and all observers agree as to the volumetric density of energy in any given space. There is also a global law of conservation of energy, stating that the total energy of the universe cannot change; this is a corollary of the local law, but not vice versa.[4][7] Conservation of energy is the mathematical consequence of translational symmetry of time (that is, the indistinguishability of time intervals taken at different time)[13] - see Noether's theorem.
According to energy conservation law the total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system.
This law is a fundamental principle of physics. It follows from the translational symmetry of time, a property of most phenomena below the cosmic scale that makes them independent of their locations on the time coordinate. Put differently, yesterday, today, and tomorrow are physically indistinguishable.
Because energy is quantity which is canonical conjugate to time, it is impossible to define exact amount of energy during any definite time interval - making it impossible to apply the law of conservation of energy. This must not be considered a "violation" of the law. We know the law still holds, because a succession of short time periods does not accumulate any violation of conservation of energy.
In quantum mechanics energy is expressed using the Hamiltonian operator. On
any time scales, the uncertainty in the energy is by
which is similar in form to the uncertainty principle (but not really mathematically equivalent thereto, since H and t are not dynamically conjugate variables, neither in classical nor in quantum mechanics).
In particle physics, this inequality permits a qualitative understanding of virtual particles which carry momentum, exchange by which with real particles is responsible for creation of all known fundamental forces (more accurately known as fundamental interactions). Virtual photons (which are simply lowest quantum mechanical energy state of photons) are also responsible for electrostatic interaction between electric charges (which results in Coulomb law), for spontaneous radiative decay of exited atomic and nuclear states, for the Casimir force, for van der Waals bond forces and some other observable phenomena.
# Energy and life
Any living organism relies on an external source of energy—radiation from the Sun in the case of green plants; chemical energy in some form in the case of animals—to be able to grow and reproduce. The daily 1500–2000 Calories (6–8 MJ) recommended for a human adult are taken as a combination of oxygen and food molecules, the latter mostly carbohydrates and fats, of which glucose (C6H12O6) and stearin (C57H110O6) are convenient examples. The food molecules are oxidised to carbon dioxide and water in the mitochondria
and some of the energy is used to convert ADP into ATP
The rest of the chemical energy in the carbohydrate or fat is converted into heat: the ATP is used as a sort of "energy currency", and some of the chemical energy it contains when split and reacted with water, is used for other metabolism (at each stage of a metabolic pathway, some chemical energy is converted into heat). Only a tiny fraction of the original chemical energy is used for work:[14]
It would appear that living organisms are remarkably inefficient (in the physical sense) in their use of the energy they receive (chemical energy or radiation), and it is true that most real machines manage higher efficiencies. However, in growing organisms the energy that is converted to heat serves a vital purpose, as it allows the organism tissue to be highly ordered with regard to the molecules it is built from. The second law of thermodynamics states that energy (and matter) tends to become more evenly spread out across the universe: to concentrate energy (or matter) in one specific place, it is necessary to spread out a greater amount of energy (as heat) across the remainder of the universe ("the surroundings").[15] Simpler organisms can achieve higher energy efficiencies than more complex ones, but the complex organisms can occupy ecological niches that are not available to their simpler brethren. The conversion of a portion of the chemical energy to heat at each step in a metabolic pathway is the physical reason behind the pyramid of biomass observed in ecology: to take just the first step in the food chain, of the estimated 124.7 Pg/a of carbon that is fixed by photosynthesis, 64.3 Pg/a (52%) are used for the metabolism of green plants,[16] i.e. reconverted into carbon dioxide and heat. | https://www.wikidoc.org/index.php/Chemical_energy | |
7444cec920fb100813520b20be34697328b0a1aa | wikidoc | Qigong | Qigong
Qigong or chi kung is an aspect of traditional Chinese medicine, some forms of which involve the coordination of different breathing patterns with various physical postures and motions of the body. Qigong is mostly taught for health maintenance purposes, but there are also some who teach it as a therapeutic intervention or practice it as a medical profession. Various forms of traditional qigong are also widely taught in conjunction with Chinese martial arts, and are especially prevalent in the advanced training of what are known as the Neijia, or internal martial arts where the object is the full mobilization and proper coordination and direction of the energies of the body as they are applied to facilitate all physical actions.
Qigong relies on the traditional Chinese belief that the body has something that might be described as an "energy field" generated and maintained by the natural respiration of the body, known as qi. Qi means breath or gas in Chinese, and, by extension, the energy produced by breathing that keeps us alive; gong means work applied to a discipline or the resultant level of technique. Qigong is then "breath work" or the art of managing one's breathing in order to achieve and maintain good health, and (especially in the martial arts) to enhance the energy mobilization and stamina of the body in coordination with the physical process of respiration.
Attitudes toward the scientific basis (or lack of it) for qigong vary markedly. Most Western medical practitioners and many practitioners of traditional Chinese medicine, as well as the Chinese government, view qigong as a set of breathing and movement exercises, with possible benefits to health through stress reduction and exercise. Others see qigong in more metaphysical terms, claiming that breathing and movement exercises can help one tap the fundamental energies of the universe.
# Uses
Today millions of people in China and around the world regularly practice qigong as a health maintenance exercise. Qigong and related disciplines are still associated with the martial arts and meditation routines practiced by Taoist and Buddhist monks, professional martial artists, and their students. Once more closely guarded, in the modern era such practices have become widely available to the general public both in China and around the world.
Medical qigong treatment has been officially recognized as a standard medical technique in Chinese hospitals since 1989. It has been included in the curriculum of major universities in China. After years of debate, the Chinese government decided to officially manage qigong through government regulation in 1996 and has also listed qigong as part of their National Health Plan.
Qigong can help practitioners to learn Diaphragmatic breathing, an important component of the relaxation response, which is important in combating stress. In contrast, Taoist qigong employs the inverse breath of inhaling to the back of the thoracic cavity rather than so-called Diaphragmatic breathing. Improper use of Diaphragmatic breathing can lead to reproductive pathologies for women. (Nan Huai-Chin, 南懷瑾（1918年——）, Meditation and the cultivation of immortality, Gu lu press, Tawain 1991 p.59)
Yan Xin (嚴新), a doctor of both Western and Chinese medicine as well as founder of the relatively popular Yan Xin Qigong school, suggests that in order for qigong to be accepted by the modern world it must pass the test of scientific study. Without such studies, Yan maintains, qigong will be dismissed as "superstition" (see "Criticism of Qigong" chapter below). In the mid-1980s he and others began systematic study of qigong in some research institutions in China and the United States. More than 20 papers
have been published.
Taijiquan, a martial art based on the principles of internal qigong, appears to be a potent intervention to prevent falls in the elderly, maintain joint mobility, and improve balance.
In 2003 the Chinese Government respectively their mass-organization "Chinese Health QiGong Association" presented the newly developed four Health Qigong Exercises.
# Beliefs
Qigong and its intimate relation to the Chinese martial arts are often associated with spirituality. Therefore, for many centuries the popular imagination has placed it in the province of the religious practitioners. This link is much stronger than with other techniques in traditional Chinese medicine. Qigong was historically practiced extensively in Taoist and Buddhist monasteries as an adjunct to martial arts training, and the claimed benefits of martial qigong practice are widely known in East Asian martial traditions and popular culture. In addition, the traditional teaching methods of most qigong schools (at least in Asia) descend from the strict teacher-disciple relationship conventions inherited in Chinese culture from Confucianism.
In some styles of qigong, it is taught that humanity and nature are inseparable, and any belief otherwise is held to be an artificial discrimination based on a limited, two-dimensional view of human life. According to this philosophy, access to higher energy states and the subsequent health benefits said to be provided by these higher states is possible through the principle of cultivating virtue (de or te 德, see Tao Te Ching, chapters 16, 19, 28, 32, 37, and 57). Cultivating virtue could be described as a process by which one comes to realize that one was never separated from the primal, undifferentiated state of being free of artificial discrimination that is the true nature of the universe. Progress toward this goal can be made with the aid of deep relaxation (meditation), and deep relaxation is facilitated by the practice of qigong.
# Criticisms of qigong
Much of the criticism of qigong involves its claimed method of operation. Both traditional Chinese and Western medicine practitioners have little argument with the notion that qigong can improve and in many cases maintain health by encouraging movement, increasing range of motion, and improving joint flexibility and resilience. However, the benefits of qigong become much more controversial when it is asserted that qigong derives its benefits from qi acting as a kind of "biological plasma" that cannot be detected by scientific instruments. Many biologists and physicists are skeptical of these claims and regard them as pseudoscientific.
Association of qigong with practices involving spirit possession have added to establishment criticism. Some experts in China have warned against practices involving the claimed evocation of demons, and practices involving the worship of gods during qigong practice.
Many proponents of qigong claim that they can directly detect and manipulate qi. Others, including some traditional Chinese practitioners, believe that qi can be viewed as a metaphor for certain biological processes, and the effectiveness of qigong can also be explained in terms of concepts more familiar to Western medicine such as stress management.
# Controversies within qigong
In the 1980s and 1990s, the increasing popularity of qigong and related practices led to the establishment of many groups and methods in China and elsewhere that have been viewed in a critical light by more traditional qigong practitioners as well as by skeptical outside observers. In their view, a large number of people started studying qigong under inadequate supervision, indeed, perhaps the majority of people today who study qigong work from books or video tapes and DVDs without supervision by a teacher. This laxness can lead to several problems, according to those who view themselves as representative of orthodox schools. Most traditional training takes many years of practice under the supervision of someone who has also learned over years, someone who can guide and prevent the student from taking an unbalanced approach to qigong practice. The othodox practitioners warn that improperly supervised practice can cause unbalanced circulation of inner energies that can eventually lead to unbalanced effects on the various systems of the body, both mental and physical.
Stories of unguided practitioners or inexpertly guided students developing chronic mental and physical health problems as a result of such training are not uncommon. The term "Qi Gong-Induced Psychosis" was included in the Diagnostic and Statistical Manual, of the American Psychiatric Association in the late 1990s, and is described as a culturally bound disorder with painful psychosomatic symptoms. Dr. Arthur Kleinman and Dr. Sing Lee from Harvard Medical School, researchers on various psychiatric topics in China, suggest that in international psychiatry this illness would be recognized as “…a specific type of brief reactive psychosis or as the precipitation of an underlying mental illness, such as schizophrenia, bipolar disorder, or posttraumatic stress disorder.”
Lee and Kleinman both claim to have had experience with patients suffering from the condition. "Many kinds of qigong share certain similarities, such as the attainment of a trance state, patterned bodily posture or movement…, the practice of which could induce mental illnesses in some of its practitioners."
# Qigong and the People's Republic of China
While some historians have suggested that in the early days of rule by the People's Republic of China there was a drive to promote the Traditional Chinese Medicine aspects of Qigong to a quasi-religious status (and therefore deviate from standard communist government policy on religion), the PRC has most recently attempted to reposition the definition of qigong to a traditional Chinese sport involving "deep breathing exercises" rather than anything to do with Qi as energy. Xinhua News Agency articles have also attempted to explain the healing "Qi emissions" of Qigong masters as a type of hypnotherapy or placebo effect. This attitude to qigong may be related to Falun Gong and Zhong Gong, which practice their own form of qigong which they claim to be for spiritual development. In the process of cracking down on the practice, The PRC government created a set of rules for qigong groups practicing in the country.
# Footnotes
- ↑ Windoe, R. K., Martins, R. K. & McNeil, D. W. (2006). Anxiety disorders in ethnic minorities. In Y. Jackson (Ed.), Encyclopedia of multicultural psychology (pp. 45-51). Thousand Oaks: Sage.
- ↑ DSM-IV General Information: Appendix I, Outline for Cultural Formulation and Glossary of Culture-Bound Syndromes)
- ↑ Anthony Spaeth, Master Li's Brave New Age, TIME ASIA, May 10, 1999, Vol. 153 No. 18
- ↑ Sing Lee, MB, BS, and Arthur Kleinman, MD, “Psychiatry in its Political and Professional Contexts: A Response to Robin Munro”, J Am Acad Psychiatry Law, 30:120–5, 2002, p 122
- ↑ Columbia University information
- ↑ Jump up to: 6.0 6.1 Xinhua News Agency article
- ↑ Cesnur.org | Qigong
Template:Contains Chinese text
Template:Chinese
Qigong or chi kung is an aspect of traditional Chinese medicine, some forms of which involve the coordination of different breathing patterns with various physical postures and motions of the body. Qigong is mostly taught for health maintenance purposes, but there are also some who teach it as a therapeutic intervention or practice it as a medical profession. Various forms of traditional qigong are also widely taught in conjunction with Chinese martial arts, and are especially prevalent in the advanced training of what are known as the Neijia, or internal martial arts where the object is the full mobilization and proper coordination and direction of the energies of the body as they are applied to facilitate all physical actions.
Qigong relies on the traditional Chinese belief that the body has something that might be described as an "energy field" generated and maintained by the natural respiration of the body, known as qi. Qi means breath or gas in Chinese, and, by extension, the energy produced by breathing that keeps us alive; gong means work applied to a discipline or the resultant level of technique. Qigong is then "breath work" or the art of managing one's breathing in order to achieve and maintain good health, and (especially in the martial arts) to enhance the energy mobilization and stamina of the body in coordination with the physical process of respiration.
Attitudes toward the scientific basis (or lack of it) for qigong vary markedly. Most Western medical practitioners and many practitioners of traditional Chinese medicine, as well as the Chinese government, view qigong as a set of breathing and movement exercises, with possible benefits to health through stress reduction and exercise. Others see qigong in more metaphysical terms, claiming that breathing and movement exercises can help one tap the fundamental energies of the universe.
# Uses
Today millions of people in China and around the world regularly practice qigong as a health maintenance exercise. Qigong and related disciplines are still associated with the martial arts and meditation routines practiced by Taoist and Buddhist monks, professional martial artists, and their students. Once more closely guarded, in the modern era such practices have become widely available to the general public both in China and around the world.
Template:Alternative medical systems
Medical qigong treatment has been officially recognized as a standard medical technique in Chinese hospitals since 1989. It has been included in the curriculum of major universities in China. After years of debate, the Chinese government decided to officially manage qigong through government regulation in 1996 and has also listed qigong as part of their National Health Plan.
Qigong can help practitioners to learn Diaphragmatic breathing, an important component of the relaxation response, which is important in combating stress. In contrast, Taoist qigong employs the inverse breath of inhaling to the back of the thoracic cavity rather than so-called Diaphragmatic breathing. Improper use of Diaphragmatic breathing can lead to reproductive pathologies for women. (Nan Huai-Chin, 南懷瑾（1918年——）, Meditation and the cultivation of immortality, Gu lu press, Tawain 1991 p.59)
Yan Xin (嚴新), a doctor of both Western and Chinese medicine as well as founder of the relatively popular Yan Xin Qigong school, suggests that in order for qigong to be accepted by the modern world it must pass the test of scientific study. Without such studies, Yan maintains, qigong will be dismissed as "superstition" (see "Criticism of Qigong" chapter below). In the mid-1980s he and others began systematic study of qigong in some research institutions in China and the United States. More than 20 papers [1]
[2] [3] [4] [5]
have been published.
Taijiquan, a martial art based on the principles of internal qigong, appears to be a potent intervention to prevent falls in the elderly, maintain joint mobility, and improve balance.
In 2003 the Chinese Government respectively their mass-organization "Chinese Health QiGong Association" presented the newly developed four Health Qigong Exercises.
# Beliefs
Qigong and its intimate relation to the Chinese martial arts are often associated with spirituality. Therefore, for many centuries the popular imagination has placed it in the province of the religious practitioners. This link is much stronger than with other techniques in traditional Chinese medicine. Qigong was historically practiced extensively in Taoist and Buddhist monasteries as an adjunct to martial arts training, and the claimed benefits of martial qigong practice are widely known in East Asian martial traditions and popular culture. In addition, the traditional teaching methods of most qigong schools (at least in Asia) descend from the strict teacher-disciple relationship conventions inherited in Chinese culture from Confucianism.
In some styles of qigong, it is taught that humanity and nature are inseparable, and any belief otherwise is held to be an artificial discrimination based on a limited, two-dimensional view of human life. According to this philosophy, access to higher energy states and the subsequent health benefits said to be provided by these higher states is possible through the principle of cultivating virtue (de or te 德, see Tao Te Ching, chapters 16, 19, 28, 32, 37, and 57). Cultivating virtue could be described as a process by which one comes to realize that one was never separated from the primal, undifferentiated state of being free of artificial discrimination that is the true nature of the universe. Progress toward this goal can be made with the aid of deep relaxation (meditation), and deep relaxation is facilitated by the practice of qigong.
# Criticisms of qigong
Much of the criticism of qigong involves its claimed method of operation. Both traditional Chinese and Western medicine practitioners have little argument with the notion that qigong can improve and in many cases maintain health by encouraging movement, increasing range of motion, and improving joint flexibility and resilience. However, the benefits of qigong become much more controversial when it is asserted that qigong derives its benefits from qi acting as a kind of "biological plasma" that cannot be detected by scientific instruments. Many biologists and physicists are skeptical of these claims and regard them as pseudoscientific.[citation needed]
Association of qigong with practices involving spirit possession have added to establishment criticism. Some experts in China have warned against practices involving the claimed evocation of demons, and practices involving the worship of gods during qigong practice.[citation needed]
Many proponents of qigong claim that they can directly detect and manipulate qi. Others, including some traditional Chinese practitioners, believe that qi can be viewed as a metaphor for certain biological processes, and the effectiveness of qigong can also be explained in terms of concepts more familiar to Western medicine such as stress management.
# Controversies within qigong
In the 1980s and 1990s, the increasing popularity of qigong and related practices led to the establishment of many groups and methods in China and elsewhere that have been viewed in a critical light by more traditional qigong practitioners as well as by skeptical outside observers. In their view, a large number of people started studying qigong under inadequate supervision, indeed, perhaps the majority of people today who study qigong work from books or video tapes and DVDs without supervision by a teacher. This laxness can lead to several problems, according to those who view themselves as representative of orthodox schools. Most traditional training takes many years of practice under the supervision of someone who has also learned over years, someone who can guide and prevent the student from taking an unbalanced approach to qigong practice. The othodox practitioners warn that improperly supervised practice can cause unbalanced circulation of inner energies that can eventually lead to unbalanced effects on the various systems of the body, both mental and physical.
Stories of unguided practitioners or inexpertly guided students developing chronic mental and physical health problems as a result of such training are not uncommon.[1] The term "Qi Gong-Induced Psychosis" was included in the Diagnostic and Statistical Manual, of the American Psychiatric Association in the late 1990s[2], and is described as a culturally bound disorder with painful psychosomatic symptoms.[3] Dr. Arthur Kleinman and Dr. Sing Lee from Harvard Medical School, researchers on various psychiatric topics in China, suggest that in international psychiatry this illness would be recognized as “…a specific type of brief reactive psychosis or as the precipitation of an underlying mental illness, such as schizophrenia, bipolar disorder, or posttraumatic stress disorder.”[4]
Lee and Kleinman both claim to have had experience with patients suffering from the condition.[citation needed] "Many kinds of qigong share certain similarities, such as the attainment of a trance state, patterned bodily posture or movement…, the practice of which could induce mental illnesses in some of its practitioners."
# Qigong and the People's Republic of China
While some historians have suggested that in the early days of rule by the People's Republic of China there was a drive to promote the Traditional Chinese Medicine aspects of Qigong to a quasi-religious status (and therefore deviate from standard communist government policy on religion),[5] the PRC has most recently attempted to reposition the definition of qigong to a traditional Chinese sport involving "deep breathing exercises" rather than anything to do with Qi as energy.[6] Xinhua News Agency articles have also attempted to explain the healing "Qi emissions" of Qigong masters as a type of hypnotherapy or placebo effect.[6] This attitude to qigong may be related to Falun Gong and Zhong Gong, which practice their own form of qigong which they claim to be for spiritual development. In the process of cracking down on the practice, The PRC government created a set of rules for qigong groups practicing in the country.[7]
# Footnotes
- ↑ Windoe, R. K., Martins, R. K. & McNeil, D. W. (2006). Anxiety disorders in ethnic minorities. In Y. Jackson (Ed.), Encyclopedia of multicultural psychology (pp. 45-51). Thousand Oaks: Sage.
- ↑ DSM-IV General Information: Appendix I, Outline for Cultural Formulation and Glossary of Culture-Bound Syndromes)
- ↑ Anthony Spaeth, Master Li's Brave New Age, TIME ASIA, May 10, 1999, Vol. 153 No. 18
- ↑ Sing Lee, MB, BS, and Arthur Kleinman, MD, “Psychiatry in its Political and Professional Contexts: A Response to Robin Munro”, J Am Acad Psychiatry Law, 30:120–5, 2002, p 122
- ↑ Columbia University information
- ↑ Jump up to: 6.0 6.1 Xinhua News Agency article
- ↑ Cesnur.org | https://www.wikidoc.org/index.php/Chi_Kung | |
f2808ab36eb90ee46c632fde6685bf59b3582cb9 | wikidoc | Chitin | Chitin
# Overview
Chitin (C8H13O5N)n (Template:PronEng) is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world. It is the main component of the cell walls of fungi, the exoskeletons of arthropods, such as crustaceans (e.g. crabs, lobsters and shrimps) and insects, including ants, beetles and butterflies, the radula of mollusks and the beaks of cephalopods, including squid and octopuses. Chitin has also proven useful for several medical and industrial purposes. Chitin is a biological substance which may be compared to the polysaccharide cellulose and to the protein keratin. Although keratin is a protein, and not a carbohydrate like chitin, both keratin and chitin have similar structural functions.
# Chemistry, physical properties and biological function
Chitin is a polysaccharide; it is synthesized from units of N-acetylglucosamine (more completely, N-acetyl-D-glucos-2-amine). These units form covalent β-1,4 linkages (similar to the linkages between glucose units forming cellulose). Chitin may therefore be described as cellulose with one hydroxyl group on each monomer substituted with an acetylamine group. This allows for increased hydrogen bonding between adjacent polymers, giving the chitin-polymer matrix increased strength.
In its unmodified form, chitin is translucent, pliable, resilient and quite tough. In arthropods, however, it is often modified, becoming embedded in a hardened proteinaceous matrix, which forms much of the exoskeleton. In its pure form it is leathery, but when encrusted in calcium carbonate it becomes much harder. The difference between the unmodified and modified forms can be seen by comparing the body wall of a caterpillar (unmodified) to a beetle (modified).
# Chitin
Chitin is one of many naturally occurring polymers. It is one of the most abundant natural materials in the world. Over time it is bio-degradable in the natural environment. Its breakdown may be catalyzed by enzymes called chitinases, secreted by microorganisms such as bacteria and fungi, and produced by some plants. Some of these microorganisms have receptors to simple sugars from the decomposition of chitin. If chitin is detected, they then produce enzymes to digest it by cleaving the glycosidic bonds in order to convert it to simple sugars and ammonia.
Chemically, chitin is closely related to chitosan (a more water-soluble derivative of chitin). It is also closely related to cellulose in that it is a long unbranched chain of glucose derivatives. Both materials contribute structure and strength, protecting the organism.
# Etymology
The English word "chitin" comes from the French word "chitine", which first appeared in 1836. These words were derived from the Latin word "chitōn", meaning mollusk. That is either influenced by, or related to the Greek word khitōn, meaning "tunic" or "frock", the Central Semitic word "*kittan", the Akkadian words "kitû" or "kita’um", meaning flax or linen, and the Sumerian word "gada" or "gida".
A similar word, "chiton", refers to a marine animal with a protective shell (also known as a "sea cradle").
# Uses
## Agriculture
Most recent studies point out that chitin is a good inducer for defense mechanisms in plants. It was recently tested as a fertilizer that can help plants develop healthy immune responses, and have a much better yield and life expectancy.
The EPA regulates chitin for agricultural use. Chitosan is derived from chitin, which is used as a biocontrol elicitor in agriculture and horticulture.
## Industrial
Chitin is used industrially in many processes. It is used in water purification, and as an additive to thicken and stabilize foods and pharmaceuticals. It also acts as a binder in dyes, fabrics, and adhesives. Industrial separation membranes and ion-exchange resins can be made from chitin. Processes to size and strengthen paper employ chitin.
## Medicine
Chitin's properties as a flexible and strong material make it favorable as surgical thread. Its biodegradibility means it wears away with time as the wound heals. Moreover, chitin has some unusual properties that accelerate healing of wounds in humans.
Occupations associated with high environmental chitin levels, such as shellfish processors, are prone to high incidences of asthma. Recent studies have suggested that chitin may play a role in a possible pathway in human allergic disease.
Specifically, mice treated with chitin develop an allergic response, characterized by a build-up of interleukin-4 expressing innate immune cells. In these treated mice, additional treatment with a chitinase enzyme abolishes the response. | Chitin
# Overview
Chitin (C8H13O5N)n (Template:PronEng) is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world. It is the main component of the cell walls of fungi, the exoskeletons of arthropods, such as crustaceans (e.g. crabs, lobsters and shrimps) and insects, including ants, beetles and butterflies, the radula of mollusks and the beaks of cephalopods, including squid and octopuses. Chitin has also proven useful for several medical and industrial purposes. Chitin is a biological substance which may be compared to the polysaccharide cellulose and to the protein keratin. Although keratin is a protein, and not a carbohydrate like chitin, both keratin and chitin have similar structural functions.
# Chemistry, physical properties and biological function
Chitin is a polysaccharide; it is synthesized from units of N-acetylglucosamine (more completely, N-acetyl-D-glucos-2-amine). These units form covalent β-1,4 linkages (similar to the linkages between glucose units forming cellulose). Chitin may therefore be described as cellulose with one hydroxyl group on each monomer substituted with an acetylamine group. This allows for increased hydrogen bonding between adjacent polymers, giving the chitin-polymer matrix increased strength.
In its unmodified form, chitin is translucent, pliable, resilient and quite tough. In arthropods, however, it is often modified, becoming embedded in a hardened proteinaceous matrix, which forms much of the exoskeleton. In its pure form it is leathery, but when encrusted in calcium carbonate it becomes much harder.[1] The difference between the unmodified and modified forms can be seen by comparing the body wall of a caterpillar (unmodified) to a beetle (modified).
# Chitin
Chitin is one of many naturally occurring polymers. It is one of the most abundant natural materials in the world. Over time it is bio-degradable in the natural environment. Its breakdown may be catalyzed by enzymes called chitinases, secreted by microorganisms such as bacteria and fungi, and produced by some plants. Some of these microorganisms have receptors to simple sugars from the decomposition of chitin. If chitin is detected, they then produce enzymes to digest it by cleaving the glycosidic bonds in order to convert it to simple sugars and ammonia.
Chemically, chitin is closely related to chitosan (a more water-soluble derivative of chitin). It is also closely related to cellulose in that it is a long unbranched chain of glucose derivatives. Both materials contribute structure and strength, protecting the organism.
# Etymology
The English word "chitin" comes from the French word "chitine", which first appeared in 1836. These words were derived from the Latin word "chitōn", meaning mollusk. That is either influenced by, or related to the Greek word khitōn, meaning "tunic" or "frock", the Central Semitic word "*kittan", the Akkadian words "kitû" or "kita’um", meaning flax or linen, and the Sumerian word "gada" or "gida".[2]
A similar word, "chiton", refers to a marine animal with a protective shell (also known as a "sea cradle").
# Uses
## Agriculture
Most recent studies point out that chitin is a good inducer for defense mechanisms in plants.[3] It was recently tested as a fertilizer that can help plants develop healthy immune responses, and have a much better yield and life expectancy.[4]
The EPA regulates chitin for agricultural use.[5] Chitosan is derived from chitin, which is used as a biocontrol elicitor in agriculture and horticulture.
## Industrial
Chitin is used industrially in many processes. It is used in water purification, and as an additive to thicken and stabilize foods and pharmaceuticals. It also acts as a binder in dyes, fabrics, and adhesives. Industrial separation membranes and ion-exchange resins can be made from chitin. Processes to size and strengthen paper employ chitin.
## Medicine
Chitin's properties as a flexible and strong material make it favorable as surgical thread. Its biodegradibility means it wears away with time as the wound heals. Moreover, chitin has some unusual properties that accelerate healing of wounds in humans.
Occupations associated with high environmental chitin levels, such as shellfish processors, are prone to high incidences of asthma. Recent studies have suggested that chitin may play a role in a possible pathway in human allergic disease.
Specifically, mice treated with chitin develop an allergic response, characterized by a build-up of interleukin-4 expressing innate immune cells. In these treated mice, additional treatment with a chitinase enzyme abolishes the response.[6] | https://www.wikidoc.org/index.php/Chitin | |
8bfd919c2b7f89153f0894f2eed89211a7421933 | wikidoc | Chives | Chives
Chives (Allium schoenoprasum) are the smallest species of the onion family Alliaceae, native to Europe, Asia and North America. They are referred to only in the plural, because they grow in clumps rather than as individual plants. Allium schoenoprasum is also the only species of Allium native to both the New and the Old World.
Its species name derives from the Greek skhoinos (sedge) and prason (onion). Its English name, chive, derives from the French word cive, which was derived from cepa, the Latin word for onion.
Culinary uses for chives involve shredding its leaves (straws) for use as condiment for fish, potatoes and soups. Because of this, it is a common household herb, frequent in gardens as well as in grocery stores. It also has insect-repelling properties which can be used in gardens to control pests.
# Biology
The chive is a bulb-forming herbaceous perennial plant, growing to 30-50 cm tall. The bulbs are slender conical, 2-3 cm long and 1 cm broad, and grow in dense clusters from the roots. The leaves are hollow tubular, up to 50 cm long, and 2-3 mm in diameter, with a soft texture, although, prior to the emergence of a flower from a leaf, it may appear stiffer than usual. The flowers are pale purple, star-shaped with six tepals, 1-2 cm wide, and produced in a dense inflorescence of 10-30 together; before opening, the inflorescence is surrounded by a papery bract. The seeds are produced in a small three-valved capsule, maturing in summer. The herb flowers from April to May in the southern parts of its habitat zones and in June in the northern parts.
Chives are the only species of Allium native to both the Old World and New. Sometimes, the plants found in North America are classified as A. schoenoprasum var. sibiricum, although this is disputed. There have been significant differences among specimens: one example was found in northern Maine growing solitary, instead of in clumps, also exhibiting dingy grey flowers.
Albeit repulsive to insects in general, due to its sulfur compounds, its flowers are attractive to bees, and it is sometimes kept to increase desired insect life.
# Uses
## Culinary
Chives are grown for their leaves, which are used for culinary purposes as condiment, which provide a somewhat milder flavour than its neighbouring Allium species.
Chives have a wide variety of culinary uses, such as in traditional dishes in France and Sweden, among others. In his 1806 book Attempt at a Flora (Försök til en flora), Retzius describes how chives are used with pancakes, soups, fish and sandwiches. It is also an ingredient of the gräddfil sauce served with the traditional herring dish served at Swedish midsummer celebrations. The flowers may also be used to garnish dishes.
Chives are one of the "fines herbes" of French cuisine, which also include tarragon, chervil and/or parsley.
Chives can be found fresh at most markets year-round, making it a readily available spice herb; it can also be dry-frozen without much impairment to its taste, giving home growers the opportunity to store large quantities harvested from their own garden.
## In cultivation
Retzius also describes how farmers would plant chives between the rocks making up the borders of their flowerbeds, to keep the plants free from pests (such as Japanese beetles).. While the growing plant repels unwanted insect life, the juice of the leaves can be used for the same purpose, as well as fighting fungal infections, mildew and scab.
Its flowers are attractive to bees, which are important for gardens with an abundance of plants in need of pollination.
## Medical uses
The medical properties of chives are similar to those of garlic, but weaker; the faint effects in comparison with garlic are probably the main reason for its limited use as a medicinal herb. Containing numerous organisulplide compounds such as allyl sulfides and alkyl sulfoxides, chives have a beneficial effect on the circulatory system, acting upon it by lowering the blood pressure. As chives are usually served in small amounts and never as the main dish, negative effects are rarely encountered, although digestive problems may occur following over-consumption.
Chives are also rich in vitamins A and C, and contain trace amounts of sulfur and iron.
# Cultivation
Chives are cultivated both for its culinary uses as well as its ornamental value; the violet flowers are often used in ornamental dry bouquets.
Chives thrive in well drained soil, rich in organic matter, with a pH of 6-7 and full sun.
Chives can be grown from seed and mature in summer, or early the following spring. Typically, chives need to be germinated at a temperature of 15 °C to 20 °C and kept moist. They can also be planted under a cloche or germinated indoors in cooler climates, then planted out later. After at least four weeks, the young shoots should be ready to be planted out.
In the winter, chives die back to the underground bulbs, with the new leaves appearing in early spring. Chives starting to look old can be cut back to about 2-5 cm; this length is also preferred when harvesting, making the unattractive yellowing appear close to the ground, so that the plant can retain its aesthetic value.
# History and cultural importance
Chives have been cultivated in Europe since the Middle Ages, although signs of its usage date back to 5000 years ago.
The Romans believed chives could relieve the pain from sunburn or a sore throat. They believed that eating chives would increase blood pressure and acted as a diuretic.
Romanian Gypsies have used chives in fortune telling.
It was believed that bunches of dried chives hung around a house would ward off disease and evil.
# Gallery
- Clump of chives
Clump of chives
- Close-up of a chive flower
Close-up of a chive flower
- Close-up of a flower
Close-up of a flower
- Capsules with seeds
Capsules with seeds
- Close-up of a clump of chives
Close-up of a clump of chives
- Chives flowering in a bed
Chives flowering in a bed | Chives
Template:Otheruses1
Chives (Allium schoenoprasum) are the smallest species of the onion family[1] Alliaceae, native to Europe, Asia and North America[2]. They are referred to only in the plural, because they grow in clumps rather than as individual plants. Allium schoenoprasum is also the only species of Allium native to both the New and the Old World.
Its species name derives from the Greek skhoinos (sedge) and prason (onion).[3] Its English name, chive, derives from the French word cive, which was derived from cepa, the Latin word for onion.[4]
Culinary uses for chives involve shredding its leaves (straws) for use as condiment for fish, potatoes and soups. Because of this, it is a common household herb, frequent in gardens as well as in grocery stores. It also has insect-repelling properties which can be used in gardens to control pests.[5]
# Biology
The chive is a bulb-forming herbaceous perennial plant, growing to 30-50 cm tall. The bulbs are slender conical, 2-3 cm long and 1 cm broad, and grow in dense clusters from the roots. The leaves are hollow tubular, up to 50 cm long, and 2-3 mm in diameter, with a soft texture, although, prior to the emergence of a flower from a leaf, it may appear stiffer than usual. The flowers are pale purple, star-shaped with six tepals, 1-2 cm wide, and produced in a dense inflorescence of 10-30 together; before opening, the inflorescence is surrounded by a papery bract. The seeds are produced in a small three-valved capsule, maturing in summer. The herb flowers from April to May in the southern parts of its habitat zones and in June in the northern parts.[6][7]
Chives are the only species of Allium native to both the Old World and New. Sometimes, the plants found in North America are classified as A. schoenoprasum var. sibiricum, although this is disputed. There have been significant differences among specimens: one example was found in northern Maine growing solitary, instead of in clumps, also exhibiting dingy grey flowers.[8]
Albeit repulsive to insects in general, due to its sulfur compounds, its flowers are attractive to bees, and it is sometimes kept to increase desired insect life.[9]
# Uses
## Culinary
Template:Limitedgeographicscope
Chives are grown for their leaves, which are used for culinary purposes as condiment, which provide a somewhat milder flavour than its neighbouring Allium species.
Chives have a wide variety of culinary uses, such as in traditional dishes in France[10] and Sweden[11], among others. In his 1806 book Attempt at a Flora (Försök til en flora), Retzius describes how chives are used with pancakes, soups, fish and sandwiches.[11] It is also an ingredient of the gräddfil sauce served with the traditional herring dish served at Swedish midsummer celebrations. The flowers may also be used to garnish dishes. [12]
Chives are one of the "fines herbes" of French cuisine, which also include tarragon, chervil and/or parsley.
Chives can be found fresh at most markets year-round, making it a readily available spice herb; it can also be dry-frozen without much impairment to its taste, giving home growers the opportunity to store large quantities harvested from their own garden.[4]
## In cultivation
Retzius also describes how farmers would plant chives between the rocks making up the borders of their flowerbeds, to keep the plants free from pests (such as Japanese beetles[13]).[11]. While the growing plant repels unwanted insect life, the juice of the leaves can be used for the same purpose, as well as fighting fungal infections, mildew and scab. [14][15][16]
Its flowers are attractive to bees, which are important for gardens with an abundance of plants in need of pollination.
## Medical uses
The medical properties of chives are similar to those of garlic, but weaker; the faint effects in comparison with garlic are probably the main reason for its limited use as a medicinal herb. Containing numerous organisulplide compounds such as allyl sulfides[17] and alkyl sulfoxides, chives have a beneficial effect on the circulatory system, acting upon it by lowering the blood pressure.[18] As chives are usually served in small amounts and never as the main dish, negative effects are rarely encountered, although digestive problems may occur following over-consumption.[18]
Chives are also rich in vitamins A and C, and contain trace amounts of sulfur and iron.[19]
# Cultivation
Chives are cultivated both for its culinary uses as well as its ornamental value; the violet flowers are often used in ornamental dry bouquets.[20]
Chives thrive in well drained soil, rich in organic matter, with a pH of 6-7 and full sun.[2]
Chives can be grown from seed and mature in summer, or early the following spring. Typically, chives need to be germinated at a temperature of 15 °C to 20 °C and kept moist. They can also be planted under a cloche or germinated indoors in cooler climates, then planted out later. After at least four weeks, the young shoots should be ready to be planted out.
In the winter, chives die back to the underground bulbs, with the new leaves appearing in early spring. Chives starting to look old can be cut back to about 2-5 cm; this length is also preferred when harvesting, making the unattractive yellowing appear close to the ground, so that the plant can retain its aesthetic value.
# History and cultural importance
Chives have been cultivated in Europe since the Middle Ages, although signs of its usage date back to 5000 years ago[4].
The Romans believed chives could relieve the pain from sunburn or a sore throat. They believed that eating chives would increase blood pressure and acted as a diuretic.[citation needed]
Romanian Gypsies have used chives in fortune telling.[19]
It was believed that bunches of dried chives hung around a house would ward off disease and evil.[19]
# Gallery
- Clump of chives
Clump of chives
- Close-up of a chive flower
Close-up of a chive flower
- Close-up of a flower
Close-up of a flower
- Capsules with seeds
Capsules with seeds
- Close-up of a clump of chives
Close-up of a clump of chives
- Chives flowering in a bed
Chives flowering in a bed | https://www.wikidoc.org/index.php/Chives | |
a926a1365864047a4b069763f250271261d8b0ff | wikidoc | Choana | Choana
# Overview
Choana (plural: Choanae) is the posterior nasal aperture.
The choanae are separated by the vomer.
# Boundaries
It is the opening between the nasal cavity and the nasopharynx.
It is therefore not a structure but a space bounded as follows:
- anteriorly and inferiorly by the horizontal plate of palatine bone,
- superiorly and posteriorly by the sphenoid bone
- laterally by the medial pterygoid plates.
# Etymology
The term is a latinization from the Greek "choanē" meaning funnel.
# Choanae in different animals
The only animals with choana are the tetrapoda, and they could as well be called Choanata (they are also the only ones with a vomeronasal organ, which has an embryonic origin from the olfactory structure).
These internal nasal passages evolved while the vertebrates still lived in water. At this point they already needed to gulp air to get enough oxygen, and rather than open their jaws each time to do this, some groups acquired small openings to breathe through as a better design.
## Fish
Fish don't have choana, instead they have a pair of external nostrils: two tubes whose frontal openings lie close to the upper jaw, and the posterior openings further behind near the eyes.
A 400-million-year-old fossil lobe-finned fish called Kenichthys campbelli has something between a choana and the external nostrils seen on other fish, which makes it look like it has a cleft palate or cleft lip. The reason seems to be that the posterior opening of the external nostrils has migrated into the mouth for some reason.
## Tetrapods
Similar migration is still seen in the tetrapod embryo, and can cause a baby to be born with a cleft palate. Why it should migrate is a mystery, since the nostrils would be useless as a breathing device before their final position inside the mouth. They could also already breath air through their spiracles.
Tetrapods are also equipped with a lacrimal duct, or tear duct. How it evolved is not known, but it has an internal connection with the choana. It's possible that the choana started as a natural crack between maxilla and premaxilla because of an incomplete fusion in air breathing animals. If this gap got wider and deeper with time, the frontal part of it would have to fuse together to avoid weakening the upper jaw, creating a small opening on the upper lip. Some more migrating, and this gap would meet the anterior pair of the external nasal openings. The posterior pair of the openings was then free to form the lacrimal duct if a migration caused them to come in contact with the eyes.
## Choanae analogues in other animals and fossils
This wouldn't been the first time the jaws evolved some sort of opening. For instance, snakes have evolved a cleft in the lower jaw, allowing them to stick out their tongue without having to open the jaw. For an animal living in water, the formation of a paired cleft on the upper jaw would be quite logical. Terrestrial vertebrates would in any case need a way to breath without needing to open their jaws each time.
Some fossil species are said to have both conventional external nostrils and a choana, but only more fossils will give a real answer to how the choanas evolved.
## Lungfish and hagfishes
In addition to tetrapods, the lungfish has internal nostrils too. These seem to have a different origin than those of the tetrapods, and lungfish have no tear duct either.
Hagfishes have a single internal nostril that opens inside the mouth cavity, while Chimaerae have open canals that leads water from their external nostrils into their mouth and through their gills. | Choana
Template:Infobox Anatomy
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Choana (plural: Choanae) is the posterior nasal aperture.
The choanae are separated by the vomer.
# Boundaries
It is the opening between the nasal cavity and the nasopharynx.
It is therefore not a structure but a space bounded as follows:
- anteriorly and inferiorly by the horizontal plate of palatine bone,
- superiorly and posteriorly by the sphenoid bone
- laterally by the medial pterygoid plates.
# Etymology
The term is a latinization from the Greek "choanē" meaning funnel.
# Choanae in different animals
The only animals with choana are the tetrapoda, and they could as well be called Choanata (they are also the only ones with a vomeronasal organ, which has an embryonic origin from the olfactory structure).
These internal nasal passages evolved while the vertebrates still lived in water. At this point they already needed to gulp air to get enough oxygen, and rather than open their jaws each time to do this, some groups acquired small openings to breathe through as a better design.
## Fish
Fish don't have choana, instead they have a pair of external nostrils: two tubes whose frontal openings lie close to the upper jaw, and the posterior openings further behind near the eyes.
A 400-million-year-old fossil lobe-finned fish called Kenichthys campbelli has something between a choana and the external nostrils seen on other fish, which makes it look like it has a cleft palate or cleft lip. The reason seems to be that the posterior opening of the external nostrils has migrated into the mouth for some reason.
## Tetrapods
Similar migration is still seen in the tetrapod embryo, and can cause a baby to be born with a cleft palate. Why it should migrate is a mystery, since the nostrils would be useless as a breathing device before their final position inside the mouth. They could also already breath air through their spiracles.
Tetrapods are also equipped with a lacrimal duct, or tear duct. How it evolved is not known, but it has an internal connection with the choana. It's possible that the choana started as a natural crack between maxilla and premaxilla because of an incomplete fusion in air breathing animals. If this gap got wider and deeper with time, the frontal part of it would have to fuse together to avoid weakening the upper jaw, creating a small opening on the upper lip. Some more migrating, and this gap would meet the anterior pair of the external nasal openings. The posterior pair of the openings was then free to form the lacrimal duct if a migration caused them to come in contact with the eyes.
## Choanae analogues in other animals and fossils
This wouldn't been the first time the jaws evolved some sort of opening. For instance, snakes have evolved a cleft in the lower jaw, allowing them to stick out their tongue without having to open the jaw. For an animal living in water, the formation of a paired cleft on the upper jaw would be quite logical. Terrestrial vertebrates would in any case need a way to breath without needing to open their jaws each time.
Some fossil species are said to have both conventional external nostrils and a choana, but only more fossils will give a real answer to how the choanas evolved.
## Lungfish and hagfishes
In addition to tetrapods, the lungfish has internal nostrils too. These seem to have a different origin than those of the tetrapods, and lungfish have no tear duct either.
Hagfishes have a single internal nostril that opens inside the mouth cavity, while Chimaerae have open canals that leads water from their external nostrils into their mouth and through their gills. | https://www.wikidoc.org/index.php/Choana | |
bebd485f347d9526866bbcace9110521c64ba833 | wikidoc | Chorea | Chorea
# Overview
Chorea sancti viti (Latin for "St. Vitus' dance") is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias. The term chorea is derived from a Greek word χορεία (a kind of dance), as the quick movements of the feet or hands are vaguely comparable to dancing or piano playing.
# Presentation
Chorea is characterized by brief, irregular contractions that are not repetitive or rhythmic, but appear to flow from one muscle to the next.
These 'dance-like' movements of chorea (from the same root word as "choreography") often occur with athetosis, which adds twisting and writhing movements.
# Causes
Chorea can occur in a variety of conditions and disorders.
- Chorea is a primary feature of Huntington's disease, a progressive, hereditary movement disorder.
- Twenty percent of children and adolescents with rheumatic fever develop Sydenham's chorea as a complication.
- Chorea may also be caused by drugs (levodopa, anti-convulsants, anti-psychotics), metabolic disorders, endocrine disorders, and vascular incidents.
## Common Causes
## Causes by Organ System
## Causes In alphabetical order
# Ballism
When chorea is serious, slight movements will become thrashing motions; this form of severe chorea is referred to as ballism. Walking may become peculiar, and include odd postures and leg movements. Unlike ataxia and dystonia, which affect the quality of voluntary movements or parkinsonism, which is a hindrance of voluntary movements, the movements of chorea and ballism occur on their own, without conscious effort.
# Diagnosis
## History and Symptoms
- Complete history required
- Psychiatric symptoms (Huntington's)
## Appearance of the Patient
## Eyes
- Appearance of Kayser-Fleischer rings in cornea is diagnostic for Wilson's disease (slit-lamp examination)
## Laboratory Findings
- Antinuclear antibody (ANA) to diagnose lupus
- Serology (ASO) or throat cultures required to rule out streptococcal infection
- Urinalysis (Wilson's)
- Serum ceruloplasmin (Wilson's)
- Thyroid function tests to diagnose hyperthyroidism
## MRI and CT
- CT scans and/or MRIs are required to rule out Huntington's disease and mass lesions
## Echocardiography or Ultrasound
- In order to diagnose carditis, an ECG may be indicated
## Other Imaging Findings
- In order to reveal cerebral and cerebellar atrophies in patients with DRPLA, various imaging studies are indicated
## Other Diagnostic Studies
- Genetic testing may be required for those patients suspected of having Huntington's disease
- Peripheral smear for diagnostic neuroacanthocytosis
# Treatment
- Disease-specific treatment for AIDS, hyperthyroidism, lupus
- Symptom resolution occurs within 15 weeks for those patients with Sydenham's chorea
- Within nine years of onset of symptoms, neuroacanthocytosis is usually fatal
- Discontinue use of drugs that may have caused drug-induced chorea
- Genetic counseling is usually recommended for those patients with Huntington's disease
## Acute Pharmacotherapies
- For patients with Wilson's disease, copper-chelating agents are recommended
- For patients with acute rheumatic fever, antibiotic therapy and possibly corticosteroids
- For patients with Huntington's disease, antidepressants, neuroleptics | Chorea
Template:Search infobox
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Chorea sancti viti (Latin for "St. Vitus' dance") is an abnormal involuntary movement disorder, one of a group of neurological disorders called dyskinesias. The term chorea is derived from a Greek word χορεία (a kind of dance), as the quick movements of the feet or hands are vaguely comparable to dancing or piano playing.
# Presentation
Chorea is characterized by brief, irregular contractions that are not repetitive or rhythmic, but appear to flow from one muscle to the next.
These 'dance-like' movements of chorea (from the same root word as "choreography") often occur with athetosis, which adds twisting and writhing movements.
# Causes
Chorea can occur in a variety of conditions and disorders.
- Chorea is a primary feature of Huntington's disease, a progressive, hereditary movement disorder.
- Twenty percent of children and adolescents with rheumatic fever develop Sydenham's chorea as a complication.
- Chorea may also be caused by drugs (levodopa, anti-convulsants, anti-psychotics), metabolic disorders, endocrine disorders, and vascular incidents.
## Common Causes
## Causes by Organ System
## Causes In alphabetical order [1] [2]
# Ballism
When chorea is serious, slight movements will become thrashing motions; this form of severe chorea is referred to as ballism. Walking may become peculiar, and include odd postures and leg movements. Unlike ataxia and dystonia, which affect the quality of voluntary movements or parkinsonism, which is a hindrance of voluntary movements, the movements of chorea and ballism occur on their own, without conscious effort.
# Diagnosis
## History and Symptoms
- Complete history required
- Psychiatric symptoms (Huntington's)
## Appearance of the Patient
## Eyes
- Appearance of Kayser-Fleischer rings in cornea is diagnostic for Wilson's disease (slit-lamp examination)
## Laboratory Findings
- Antinuclear antibody (ANA) to diagnose lupus
- Serology (ASO) or throat cultures required to rule out streptococcal infection
- Urinalysis (Wilson's)
- Serum ceruloplasmin (Wilson's)
- Thyroid function tests to diagnose hyperthyroidism
## MRI and CT
- CT scans and/or MRIs are required to rule out Huntington's disease and mass lesions
## Echocardiography or Ultrasound
- In order to diagnose carditis, an ECG may be indicated
## Other Imaging Findings
- In order to reveal cerebral and cerebellar atrophies in patients with DRPLA, various imaging studies are indicated
## Other Diagnostic Studies
- Genetic testing may be required for those patients suspected of having Huntington's disease
- Peripheral smear for diagnostic neuroacanthocytosis
# Treatment
- Disease-specific treatment for AIDS, hyperthyroidism, lupus
- Symptom resolution occurs within 15 weeks for those patients with Sydenham's chorea
- Within nine years of onset of symptoms, neuroacanthocytosis is usually fatal
- Discontinue use of drugs that may have caused drug-induced chorea
- Genetic counseling is usually recommended for those patients with Huntington's disease
## Acute Pharmacotherapies
- For patients with Wilson's disease, copper-chelating agents are recommended
- For patients with acute rheumatic fever, antibiotic therapy and possibly corticosteroids
- For patients with Huntington's disease, antidepressants, neuroleptics | https://www.wikidoc.org/index.php/Chorea | |
85646470673ddf1a37501c03d844da1f3b8c0985 | wikidoc | Hiccup | Hiccup
A hiccup or hiccough (normally pronounced "HICK-up" (Template:IPAEng) regardless of spelling) is an involuntary spasm of the diaphragm; typically this repeats several times a minute. The sudden rush of air into the lungs causes the epiglottis to close, creating the "hic" noise. A bout of hiccups generally resolves itself without intervention, although many home remedies are in circulation that claim to shorten the duration, and medication is occasionally necessary. By extension, the term "hiccup" is also used to describe a small and unrepeated aberration in an otherwise consistent pattern. The medical term is singultus.
While many cases develop spontaneously, hiccups are known to develop often in specific situations, such as eating too quickly, taking a cold drink while eating a hot meal, belching, eating very hot or spicy food, laughing vigorously or coughing, drinking an alcoholic beverage to excess, crying out loud (sobbing causes air to enter the stomach), some smoking situations where abnormal inhalation can occur (in tobacco or other smoke like cannabis, perhaps triggered by precursors to coughing), or electrolyte imbalance. Hiccups may be caused by pressure to the phrenic nerve by other anatomical structures, or rarely by tumors and certain kidney disease. It is reported that 30% of chemotherapy patients suffer singultus as a side effect of treatment. (American Cancer Society) Diaphragmatic irritation can lead to hiccups.
# Purpose
One possible beneficial effect of hiccups is to dislodge foreign pieces of food, which have become stuck in the esophagus, or which are traveling too slowly. When a piece of food is swallowed that is too large for the natural peristalsis of the esophagus to move the food quickly into the stomach, it applies pressure on the phrenic nerve, invoking the hiccup reflex. This causes the diaphragm to contract, creating a vacuum in the thoracic cavity, which creates a region of low pressure on the side of the lump of food nearest the stomach, and a region of high pressure on the side of the lump of food nearest the mouth. This lungs differential across the food creates a force, which assists peristalsis. In humans, gravity partially assists peristalsis, but in quadrupeds and many marine vertebrates, their oesophagi run roughly perpendicular to the force of gravity, so that gravity provides little assistance. The hiccup mechanism likely evolved as an aid to peristalsis in our ancestors. It now only appears to offer little benefit.
Ultrasound scans have also shown that babies in-utero experience hiccups. Some hypotheses suggest that hiccups are a muscle exercise for the respiratory system prior to birth, or that they prevent amniotic fluid from entering the lungs. More research is required to ascertain their true nature, origins, and purpose, if any.
# Phylogenetic hypothesis
Christian Straus and co-workers at the Respiratory Research Group, University of Calgary, Canada, propose that the hiccup is an evolutionary remnant of earlier amphibian respiration; amphibians such as frogs and toads gulp air and water via a rather simple motor reflex akin to mammalian hiccuping. In support of this idea, they observe that the motor pathways that enable hiccuping form early during fetal development, before the motor pathways that enable normal lung ventilation form; thus according to recapitulation theory the hiccup is evolutionarily antecedent to advanced lung respiration. Additionally, they point out that hiccups and amphibian gulping are inhibited by elevated CO2 and can be completely stopped by the drug Baclofen (a GABAB receptor agonist), illustrating a shared physiology and evolutionary heritage. These proposals would explain why premature infants spend 2.5% of their time hiccuping, indeed they are gulping just like amphibians, as their lungs are not yet fully formed.
# Amniotic/atmospheric hypothesis
Another explanation, the amniotic/atmospheric hypothesis, holds that there are two distinct systems in the brain for controlling respiration: one that is used when the fetus is respiring amniotic fluid during its time in the womb, and another that only comes into use following birth, used for breathing air. Since amniotic fluid is much more viscous than air, a much greater effort is required from the diaphragm to inhale it. If this amniotic breathing system becomes dominant for any reason during life outside the womb, the result will be a momentary, very forceful effort at inhalation. The body senses that things are not correct, and since so much force is actually dangerous to the lungs and other organs, the system is immediately preempted and switched back to the atmospheric system. However, this preemptive control gradually relaxes, making the phenomenon cyclic as long as there is underlying activation of the amniotic respiration system: as the preemptive control falls below the threshold, the amniotic routine resumes control, only to be preempted again, and this cycle continues until the underlying conditions leading to the amniotic breathing activation revert to their normal state – at which point the hiccups stop. This theory is supported by the finding that hiccups are more common in premature newborns, as in these cases the atmospheric respiration system is less prepared to take precedence over the amniotic respiration system.
## Causes
## Drug Side Effect
- Dexamethasone
- Tiagabine
# Home remedies
The following are some commonly suggested home remedies. While numerous remedies are offered, they mostly fall into a few broad categories. These categories include purely psychosomatic cures centered around relaxation and distraction, cures involving swallowing and eating (with the rationale generally that this would remove irritants or reset mechanisms in the affected region), and cures involving controlled/altered breathing.
The first two categories may prove effective for many short lived and minor cases of hiccups. For instance, with an assistant applying pressure to one's ears, drinking any quantity of liquid whilst holding one's nose is a common home remedy for hiccups. However, those suffering from an intractable case may become desperate sorting through various ineffective home remedies. Many of the cures centered around controlled breathing (i.e. holding breath) are often ineffective for prolonged hiccups crisis, but do have a significant efficacy for the most casual, short lasting cases. For these scenarios, the underlying rationale could be the displacement of an irritated nerve through prolonged diaphragmatic expansion.
However, one respiratory remedy has a fairly sound rationale underlying it. Breathing into a bag or small enclosed container (ensuring that it is completely sealed around the mouth and nose) induces a state that is termed respiratory acidosis. The effect is caused by increasing the amount of inspired carbon dioxide, which then increases the level of carbon dioxide in the serum. These increased levels of CO2 lower the pH in the blood, hence creating a state of acidosis. This state of acidosis produces vasodilation and depression of the central nervous system. The effect allows for increased blood flow to the affected muscles, and suppression of the aberrant nervous impulses. Inducing a state of acidemia through hypoventilation is particularly effective in curing hiccups because the diaphragm rests directly against the pulmonary vasculature that is then flowing with especially low pH blood. This is a potentially dangerous action; and should only be done with another person present. As the serum CO2 level rises abruptly, the person will begin to feel lightheaded and within a few minutes will pass out. If done without a spotter, the person might either injure him or herself as he or she passes out, or pass out in such a way that the bag or container continues to prevent oxygen intake (see also asphyxia).
Additionally, another respiratory remedy appears to be of the most effective in treating persistent hiccups. One breathes out all the air that they are able to in one long exhalation then breathes in all the air they feel they possibly can in one continuous inhalation. The person then attempts to breathe in even more air in a series of short powerful puffs, until their lungs cannot hold any more. The person remains in this state for as long as they feel a small gas bubble coming at the very base of the throat, ready to be burped. Although the success rate is not 100%, many people find this method consistently works. One scientific explanation for this method is that, by breathing an extreme load of air, the lungs tend to take more space in the chest, applying pressure on the surrounding content. The so-called gas bubble, which was located in an abnormal location potentially disturbing a nerve and causing the spasm, is then released.
Psychosomatic
- Distraction from one's hiccup (e.g. being startled, asked a perplexing question, or counting in reverse from 100 down)
- Concentration on one's hiccups - using sheer will to stop them
Respiratory
- Breathing slowly and deeply in while thinking 'breathing out' and breathing slowly and fully out while thinking 'breathing in'
- Holding one's breath while optionally squeezing one's stomach
- Breathing deeply through the nose, then exhaling slowly through the mouth
- Exhaling all the air from one's lungs and holding one's breath while swallowing water or saliva
- Smoking a cigarette
- Blowing up a balloon
- Inducing sneezing
Other
- In babies, hiccups are usually immediately stopped by the suckling reflex, either by breastfeeding or simply by insertion of a finger, bottle teat or dummy into the baby's mouth.
- Take your right hand, and push it on your left arm.
- Pinch your ear lobe and breath normally. Can turn into second-nature (psychosomatic). *Works on some Dogs too.
- Giving the person suffering from hiccups a sudden and unexpected fright (for example, by shouting at them) can have the effect of ending a bout of hiccups.
# Medical treatment
Ordinary hiccups are cured easily without medical intervention; in most cases they can be stopped simply by forgetting about them. However, there are a number of anecdotally prescribed treatments for casual cases of hiccups. These include being startled, drinking water while upside down, eating something very sweet, for example a tart (particularly lemon juice) , and anything that interrupts one's breathing. Another method is to exhale air into a small paper bag and to immediately re-inhale that air from it.Drink water quickly and vigorous burping.
Hiccups are treated medically only in severe and persistent (termed "intractable") cases (such as in the case of a 15 year old girl who in 2007 hiccuped continuously for five weeks ). Haloperidol (Haldol, an anti-psychotic and sedative), metoclopramide (Reglan, a gastrointestinal stimulant), and chlorpromazine (Thorazine, an anti-psychotic with strong sedative effects) are used in cases of intractable hiccups. In severe or resistant cases, baclofen (an anti-spasmodic) is sometimes required to suppress hiccups. Effective treatment with sedatives often requires a dose that renders the person either unconscious or highly lethargic. Hence, medicating singultus is done short-term, as the affected individual cannot continue with normal life activities while taking the medication.
Persistent and intractable hiccups due to electrolyte imbalance (hypokalemia, hyponatremia) may benefit from drinking a carbonated beverage containing salt to balance out the potassium-sodium tae in the nervous system. The carbonation promotes quicker absorption.
The administration of intranasal vinegar is thought to be safe and handy method to stimulate dorsal wall of nasopharynx, where the pharyngeal branch of the glossopharyngeal nerve (afferent of the hiccup reflex arc) is distributed.
Dr. Bryan R. Payne, a neurosurgeon at the Louisiana State University Health Sciences Center in New Orleans, has had some success with an experimental new procedure in which a vagus nerve stimulator is implanted in the upper chest of patients with an intractable case of hiccups. "It sends rhythmic bursts of electricity to the brain by way of the vagus nerve, which passes through the neck. The Food and Drug Administration approved the vagus nerve stimulator in 1997 as a way to control seizures in some patients with epilepsy. In 2005, the agency endorsed the use of the stimulator as a treatment of last resort for people with severe depression."
In 2006, Francis Fesmire of the University of Tennessee College of Medicine received an Ig Nobel prize for medicine after he published "Termination of intractable hiccups with digital rectal massage" in 1988. In an attempt to block the runaway messages on the vagus nerve, Fesmire found that stimulation of the vagus nerve by digital rectal massage worked, stopping a bout of hiccupping.
# Long-term cases
American man Charles Osborne had the hiccups for 68 years, from 1922 to 1990, and was entered in the Guinness World Records as the man with the Longest Attack of Hiccups.
In January 2007, teenager Jennifer Mee from Florida in the United States hiccuped for five weeks, from January 23, 2007 until February 28, 2007.
A man in Lincolnshire, England was reported to have had hiccups for at least twenty two weeks from February 2007.
A man who lives in Belfast, Northern Ireland has had intractable hiccups for five years and has had two major operations so far to try to stop his hiccups. | Hiccup
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]
A hiccup or hiccough (normally pronounced "HICK-up" (Template:IPAEng) regardless of spelling) is an involuntary spasm of the diaphragm; typically this repeats several times a minute. The sudden rush of air into the lungs causes the epiglottis to close, creating the "hic" noise. A bout of hiccups generally resolves itself without intervention, although many home remedies are in circulation that claim to shorten the duration, and medication is occasionally necessary. By extension, the term "hiccup" is also used to describe a small and unrepeated aberration in an otherwise consistent pattern. The medical term is singultus.
While many cases develop spontaneously, hiccups are known to develop often in specific situations, such as eating too quickly, taking a cold drink while eating a hot meal, belching, eating very hot or spicy food, laughing vigorously or coughing, drinking an alcoholic beverage to excess, crying out loud (sobbing causes air to enter the stomach), some smoking situations where abnormal inhalation can occur (in tobacco or other smoke like cannabis, perhaps triggered by precursors to coughing), or electrolyte imbalance. Hiccups may be caused by pressure to the phrenic nerve by other anatomical structures, or rarely by tumors and certain kidney disease. It is reported that 30% of chemotherapy patients suffer singultus as a side effect of treatment. (American Cancer Society) Diaphragmatic irritation can lead to hiccups.
# Purpose
One possible beneficial effect of hiccups is to dislodge foreign pieces of food, which have become stuck in the esophagus, or which are traveling too slowly. When a piece of food is swallowed that is too large for the natural peristalsis of the esophagus to move the food quickly into the stomach, it applies pressure on the phrenic nerve, invoking the hiccup reflex. This causes the diaphragm to contract, creating a vacuum in the thoracic cavity, which creates a region of low pressure on the side of the lump of food nearest the stomach, and a region of high pressure on the side of the lump of food nearest the mouth. This lungs differential across the food creates a force, which assists peristalsis. In humans, gravity partially assists peristalsis, but in quadrupeds and many marine vertebrates, their oesophagi run roughly perpendicular to the force of gravity, so that gravity provides little assistance. The hiccup mechanism likely evolved as an aid to peristalsis in our ancestors. It now only appears to offer little benefit.
Ultrasound scans have also shown that babies in-utero experience hiccups. Some hypotheses suggest that hiccups are a muscle exercise for the respiratory system prior to birth, or that they prevent amniotic fluid from entering the lungs[3]. More research is required to ascertain their true nature, origins, and purpose, if any.
# Phylogenetic hypothesis
Christian Straus and co-workers at the Respiratory Research Group, University of Calgary, Canada, propose that the hiccup is an evolutionary remnant of earlier amphibian respiration; amphibians such as frogs and toads gulp air and water via a rather simple motor reflex akin to mammalian hiccuping.[1] In support of this idea, they observe that the motor pathways that enable hiccuping form early during fetal development, before the motor pathways that enable normal lung ventilation form; thus according to recapitulation theory the hiccup is evolutionarily antecedent to advanced lung respiration. Additionally, they point out that hiccups and amphibian gulping are inhibited by elevated CO2 and can be completely stopped by the drug Baclofen (a GABAB receptor agonist), illustrating a shared physiology and evolutionary heritage. These proposals would explain why premature infants spend 2.5% of their time hiccuping, indeed they are gulping just like amphibians, as their lungs are not yet fully formed.[2]
# Amniotic/atmospheric hypothesis
Another explanation, the amniotic/atmospheric hypothesis, holds that there are two distinct systems in the brain for controlling respiration: one that is used when the fetus is respiring amniotic fluid during its time in the womb, and another that only comes into use following birth, used for breathing air. Since amniotic fluid is much more viscous than air, a much greater effort is required from the diaphragm to inhale it. If this amniotic breathing system becomes dominant for any reason during life outside the womb, the result will be a momentary, very forceful effort at inhalation. The body senses that things are not correct, and since so much force is actually dangerous to the lungs and other organs, the system is immediately preempted and switched back to the atmospheric system. However, this preemptive control gradually relaxes, making the phenomenon cyclic as long as there is underlying activation of the amniotic respiration system: as the preemptive control falls below the threshold, the amniotic routine resumes control, only to be preempted again, and this cycle continues until the underlying conditions leading to the amniotic breathing activation revert to their normal state – at which point the hiccups stop. This theory is supported by the finding that hiccups are more common in premature newborns, as in these cases the atmospheric respiration system is less prepared to take precedence over the amniotic respiration system.
## Causes
## Drug Side Effect
- Dexamethasone
- Tiagabine
# Home remedies
The following are some commonly suggested home remedies. While numerous remedies are offered, they mostly fall into a few broad categories. These categories include purely psychosomatic cures centered around relaxation and distraction, cures involving swallowing and eating (with the rationale generally that this would remove irritants or reset mechanisms in the affected region), and cures involving controlled/altered breathing.
The first two categories may prove effective for many short lived and minor cases of hiccups. For instance, with an assistant applying pressure to one's ears, drinking any quantity of liquid whilst holding one's nose is a common home remedy for hiccups. However, those suffering from an intractable case may become desperate sorting through various ineffective home remedies. Many of the cures centered around controlled breathing (i.e. holding breath) are often ineffective for prolonged hiccups crisis, but do have a significant efficacy for the most casual, short lasting cases. For these scenarios, the underlying rationale could be the displacement of an irritated nerve through prolonged diaphragmatic expansion.
However, one respiratory remedy has a fairly sound rationale underlying it. Breathing into a bag or small enclosed container (ensuring that it is completely sealed around the mouth and nose) induces a state that is termed respiratory acidosis. The effect is caused by increasing the amount of inspired carbon dioxide, which then increases the level of carbon dioxide in the serum. These increased levels of CO2 lower the pH in the blood, hence creating a state of acidosis. This state of acidosis produces vasodilation and depression of the central nervous system. The effect allows for increased blood flow to the affected muscles, and suppression of the aberrant nervous impulses. Inducing a state of acidemia through hypoventilation is particularly effective in curing hiccups because the diaphragm rests directly against the pulmonary vasculature that is then flowing with especially low pH blood. This is a potentially dangerous action; and should only be done with another person present. As the serum CO2 level rises abruptly, the person will begin to feel lightheaded and within a few minutes will pass out. If done without a spotter, the person might either injure him or herself as he or she passes out, or pass out in such a way that the bag or container continues to prevent oxygen intake (see also asphyxia).
Additionally, another respiratory remedy appears to be of the most effective in treating persistent hiccups. One breathes out all the air that they are able to in one long exhalation then breathes in all the air they feel they possibly can in one continuous inhalation. The person then attempts to breathe in even more air in a series of short powerful puffs, until their lungs cannot hold any more. The person remains in this state for as long as they feel a small gas bubble coming at the very base of the throat, ready to be burped. Although the success rate is not 100%, many people find this method consistently works. One scientific explanation for this method is that, by breathing an extreme load of air, the lungs tend to take more space in the chest, applying pressure on the surrounding content. The so-called gas bubble, which was located in an abnormal location potentially disturbing a nerve and causing the spasm, is then released.
Psychosomatic
- Distraction from one's hiccup (e.g. being startled, asked a perplexing question, or counting in reverse from 100 down)
- Concentration on one's hiccups - using sheer will to stop them
Respiratory
- Breathing slowly and deeply in while thinking 'breathing out' and breathing slowly and fully out while thinking 'breathing in'
- Holding one's breath while optionally squeezing one's stomach
- Breathing deeply through the nose, then exhaling slowly through the mouth
- Exhaling all the air from one's lungs and holding one's breath while swallowing water or saliva
- Smoking a cigarette
- Blowing up a balloon
- Inducing sneezing
Other
- In babies, hiccups are usually immediately stopped by the suckling reflex, either by breastfeeding or simply by insertion of a finger, bottle teat or dummy into the baby's mouth.
- Take your right hand, and push it on your left arm.
- Pinch your ear lobe and breath normally. Can turn into second-nature (psychosomatic). *Works on some Dogs too.
- Giving the person suffering from hiccups a sudden and unexpected fright (for example, by shouting at them) can have the effect of ending a bout of hiccups.
# Medical treatment
Ordinary hiccups are cured easily without medical intervention; in most cases they can be stopped simply by forgetting about them. However, there are a number of anecdotally prescribed treatments for casual cases of hiccups. These include being startled, drinking water while upside down, eating something very sweet, for example a tart (particularly lemon juice) [4], and anything that interrupts one's breathing. Another method is to exhale air into a small paper bag and to immediately re-inhale that air from it.Drink water quickly and vigorous burping.
Hiccups are treated medically only in severe and persistent (termed "intractable") cases (such as in the case of a 15 year old girl who in 2007 hiccuped continuously for five weeks [5]). Haloperidol (Haldol, an anti-psychotic and sedative), metoclopramide (Reglan, a gastrointestinal stimulant), and chlorpromazine (Thorazine, an anti-psychotic with strong sedative effects) are used in cases of intractable hiccups. In severe or resistant cases, baclofen (an anti-spasmodic) is sometimes required to suppress hiccups. Effective treatment with sedatives often requires a dose that renders the person either unconscious or highly lethargic. Hence, medicating singultus is done short-term, as the affected individual cannot continue with normal life activities while taking the medication.
Persistent and intractable hiccups due to electrolyte imbalance (hypokalemia, hyponatremia) may benefit from drinking a carbonated beverage containing salt to balance out the potassium-sodium tae in the nervous system. The carbonation promotes quicker absorption.
The administration of intranasal vinegar is thought to be safe and handy method to stimulate dorsal wall of nasopharynx, where the pharyngeal branch of the glossopharyngeal nerve (afferent of the hiccup reflex arc) is distributed.[3]
Dr. Bryan R. Payne, a neurosurgeon at the Louisiana State University Health Sciences Center in New Orleans, has had some success with an experimental new procedure in which a vagus nerve stimulator is implanted in the upper chest of patients with an intractable case of hiccups. "It sends rhythmic bursts of electricity to the brain by way of the vagus nerve, which passes through the neck. The Food and Drug Administration approved the vagus nerve stimulator in 1997 as a way to control seizures in some patients with epilepsy. In 2005, the agency endorsed the use of the stimulator as a treatment of last resort for people with severe depression."[6]
In 2006, Francis Fesmire of the University of Tennessee College of Medicine received an Ig Nobel prize for medicine after he published "Termination of intractable hiccups with digital rectal massage" in 1988.[4] In an attempt to block the runaway messages on the vagus nerve, Fesmire found that stimulation of the vagus nerve by digital rectal massage worked, stopping a bout of hiccupping. [7]
# Long-term cases
American man Charles Osborne had the hiccups for 68 years, from 1922 to 1990, and was entered in the Guinness World Records as the man with the Longest Attack of Hiccups.
In January 2007, teenager Jennifer Mee from Florida in the United States hiccuped for five weeks, from January 23, 2007 until February 28, 2007.[5]
A man in Lincolnshire, England was reported to have had hiccups for at least twenty two weeks from February 2007.
A man who lives in Belfast, Northern Ireland has had intractable hiccups for five years and has had two major operations so far to try to stop his hiccups.[6] | https://www.wikidoc.org/index.php/Chronic_hiccup | |
f71720dc520136d69bb26ac523ebaa78383c627c | wikidoc | Cicuta | Cicuta
Cicuta (Water Hemlock or Cowbane) is a small genus of four species of highly poisonous flowering plants in the family Apiaceae, native to temperate regions of the Northern Hemisphere, mainly North America. They are perennial herbaceous plants which grow up to 2 m tall. The species grow in wet meadows, along streambanks and other wet and marshy areas.
Although water hemlock bears a superficial resemblance to poison hemlock (Conium genus)--and is a member of the same family--the species are distinct.
# Appearance
The stems are smooth, branching, swollen at the base, purple-striped, or mottled (C. malculata only), and hollow except for partitions at the junction of the leaves and stem. The leaves are alternate, tripinnate, only coarsely toothed, unlike the ferny, lacy leaves found in many other members of the Apiaceae. The flowers are small, white and clustered in the umbrella shape so familiar to this family. An oily, yellow liquid oozes from cuts to the stems and roots. This liquid has a rank smell resembling that of parsnips, carrots or mice.
# Toxicity
The plant is occasionally mistaken for parsnips, due to its clusters of white tuberous roots; this is an often fatal error, as the Cicuta is extremely poisonous. Indeed, some consider water hemlock to be North America's most toxic plant. Cicuta is fatal when swallowed, causing violent and painful convulsions. Though a number of people have died from water hemlock poisoning over the centuries, livestock have long been the worst affected (hence the name "cowbane"), causing death in as little as 15 minutes. ,
The chief poison is cicutoxin, an unsaturated aliphatic alcohol that is most concentrated in the roots. Upon human consumption, nausea, vomiting, and tremors occur within 30-60 minutes, followed by severe cramps, projectile vomiting, and convulsions. There are occasional long-term effects, like retrograde amnesia.
- Cicuta bulbifera - Bulblet-bearing Water Hemlock. Northern North America.
- Cicuta douglasii - Western Water Hemlock. Western North America.
- Cicuta maculata - Spotted Water Hemlock. North America (widespread).
- Cicuta virosa - Cowbane or Northern Water Hemlock. Northern Europe and Asia, also Alaska. | Cicuta
Cicuta (Water Hemlock or Cowbane) is a small genus of four species of highly poisonous flowering plants in the family Apiaceae, native to temperate regions of the Northern Hemisphere, mainly North America. They are perennial herbaceous plants which grow up to 2 m tall. The species grow in wet meadows, along streambanks and other wet and marshy areas.
Although water hemlock bears a superficial resemblance to poison hemlock (Conium genus)--and is a member of the same family--the species are distinct.
# Appearance
The stems are smooth, branching, swollen at the base, purple-striped, or mottled (C. malculata only), and hollow except for partitions at the junction of the leaves and stem. The leaves are alternate, tripinnate, only coarsely toothed, unlike the ferny, lacy leaves found in many other members of the Apiaceae. The flowers are small, white and clustered in the umbrella shape so familiar to this family. An oily, yellow liquid oozes from cuts to the stems and roots. This liquid has a rank smell resembling that of parsnips, carrots or mice.
# Toxicity
The plant is occasionally mistaken for parsnips, due to its clusters of white tuberous roots; this is an often fatal error, as the Cicuta is extremely poisonous. Indeed, some consider water hemlock to be North America's most toxic plant.[1] Cicuta is fatal when swallowed, causing violent and painful convulsions. Though a number of people have died from water hemlock poisoning over the centuries, livestock have long been the worst affected (hence the name "cowbane"), causing death in as little as 15 minutes. [2],[3]
The chief poison is cicutoxin, an unsaturated aliphatic alcohol that is most concentrated in the roots. Upon human consumption, nausea, vomiting, and tremors occur within 30-60 minutes, followed by severe cramps, projectile vomiting, and convulsions. There are occasional long-term effects, like retrograde amnesia.[4]
- Cicuta bulbifera - Bulblet-bearing Water Hemlock. Northern North America.
- Cicuta douglasii - Western Water Hemlock. Western North America.
- Cicuta maculata - Spotted Water Hemlock. North America (widespread).
- Cicuta virosa - Cowbane or Northern Water Hemlock. Northern Europe and Asia, also Alaska.
# External links
- Purdue University: "27. Spotted Water Hemlock". Accessed 1/27/07.
- Rook.org: "Spotted Water Hemlock, Cicuta maculata." Accessed 1/27/07. | https://www.wikidoc.org/index.php/Cicuta | |
2d32d4901d390d8540fe0c9ea8686772ecc21416 | wikidoc | Cilium | Cilium
# Overview
A cilium (plural cilia) is an organelle found in eukaryotic cells. Cilia are tail-like projections extending approximately 5–10 micrometers outwards from the cell body.
There are two types of cilia: motile cilia, which constantly beat in a single direction, and non-motile cilia, which typically serve as sensory organelles. Along with flagella, they make up a group of organelles known as undulipodia.
# Types and distribution
Cilia are rare in plants, occurring most notably in cycads. Ciliates possess motile cilia exclusively and use them for either locomotion or to simply move liquid over their surface. Some ciliates bear groups of cilia that are fused together into large mobile projections called cirri (singular, cirrus).
Larger eukaryotes, such as mammals, have motile cilia as well. Motile cilia are rarely found alone, usually present on a cell's surface in large numbers and beating in coordinated waves. In humans, for example, motile cilia are found in the lining of the trachea (windpipe), where they sweep mucus and dirt out of the lungs. In female mammals, the beating of cilia in the Fallopian tubes moves the ovum from the ovary to the uterus.
In contrast to motile cilia, non-motile cilia usually occur one per cell. The outer segment of the rod photoreceptor cell in the human eye is connected to its cell body with a specialized non-motile cilium. The dendritic knob of the olfactory neuron, where the odorant receptors are located, is also carrying non-motile cilia (about 10 cilia / dendritic knobs). Aside from these specialized examples, almost all mammalian cells have a single non-motile primary cilium. Although the primary cilium has historically been one of the oldest cellular organelles to be studied (at least since 1898), only a small group of devotees have followed it until its importance began to become clear in the late 1990. Recent findings regarding its physiological roles in chemical sensation, signal transduction, and control of cell growth, have led scientists to acknowledge its importance in cell function, with the discovery of its role in diseases not previously recognized to involve the dysgenesis and dysfunction of cilia, such as polycystic kidney disease and congenital heart disease.
# Assembly and maintenance
To grow a cilium, the building blocks of the cilia such as tubulins and other partially assembled axonemal proteins are added to the ciliary tips which point away from the cell body. In most species bi-directional motility called intraflagellar transport or IFT plays an essential role to move these building materials from the cell body to the assembly site. IFT also carries the disassembled material to be recycled from the ciliary tip back to the cell body. By regulating the equilibrium between these two IFT proceses, the length of cilia can be maintained dynamically.
Exceptions where IFT is not present include Plasmodium falciparum which is one of the species of Plasmodium that cause malaria in humans. In this parasite, cilia assemble in the cytoplasm.
# Cilium-related disease
File:Eukaryotic cilium diagram en.svg
Ciliary defects can lead to several human diseases. Genetic mutations compromising the proper functioning of cilia can cause chronic disorders such as primary ciliary dyskinesia (PCD). In addition, a defect of the primary cilium in the renal tube cells can lead to polycystic kidney disease (PKD). In another genetic disorder called Bardet-Biedl syndrome (BBS), the mutant gene products are the components in the basal body and cilia.
Lack of functional cilia in mammalian Fallopian tubes can cause ectopic pregnancy. A fertilized ovum may not reach the uterus if the cilia are unable to move it there. In such a case, the ovum will implant in the Fallopian tubes, causing a tubal pregnancy, the most common form of ectopic pregnancy.
Since the flagellum of human sperm is actually a modified cilium, ciliary dysfunction can also be responsible for male infertility.
Of interest, there is an association of primary ciliary dyskinesia with left-right anatomic abnormalities such as situs inversus (a combination of findings known as Kartagener's syndrome) and other heterotaxic defects. These left-right anatomic abnormalities can also result in congenital heart disease. In fact, it has been shown that proper cilial function is responsible for the normal left-right asymmetry in mammals. | Cilium
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
A cilium (plural cilia) is an organelle found in eukaryotic cells. Cilia are tail-like projections extending approximately 5–10 micrometers outwards from the cell body.
There are two types of cilia: motile cilia, which constantly beat in a single direction, and non-motile cilia, which typically serve as sensory organelles. Along with flagella, they make up a group of organelles known as undulipodia.
# Types and distribution
Cilia are rare in plants, occurring most notably in cycads. Ciliates possess motile cilia exclusively and use them for either locomotion or to simply move liquid over their surface. Some ciliates bear groups of cilia that are fused together into large mobile projections called cirri (singular, cirrus).
Larger eukaryotes, such as mammals, have motile cilia as well. Motile cilia are rarely found alone, usually present on a cell's surface in large numbers and beating in coordinated waves. In humans, for example, motile cilia are found in the lining of the trachea (windpipe), where they sweep mucus and dirt out of the lungs. In female mammals, the beating of cilia in the Fallopian tubes moves the ovum from the ovary to the uterus.
In contrast to motile cilia, non-motile cilia usually occur one per cell. The outer segment of the rod photoreceptor cell in the human eye is connected to its cell body with a specialized non-motile cilium. The dendritic knob of the olfactory neuron, where the odorant receptors are located, is also carrying non-motile cilia (about 10 cilia / dendritic knobs). Aside from these specialized examples, almost all mammalian cells have a single non-motile primary cilium. Although the primary cilium has historically been one of the oldest cellular organelles to be studied (at least since 1898), only a small group of devotees have followed it until its importance began to become clear in the late 1990. Recent findings regarding its physiological roles in chemical sensation, signal transduction, and control of cell growth, have led scientists to acknowledge its importance in cell function, with the discovery of its role in diseases not previously recognized to involve the dysgenesis and dysfunction of cilia, such as polycystic kidney disease[1] and congenital heart disease[2].
# Assembly and maintenance
To grow a cilium, the building blocks of the cilia such as tubulins and other partially assembled axonemal proteins are added to the ciliary tips which point away from the cell body. In most species bi-directional motility called intraflagellar transport or IFT plays an essential role to move these building materials from the cell body to the assembly site. IFT also carries the disassembled material to be recycled from the ciliary tip back to the cell body. By regulating the equilibrium between these two IFT proceses, the length of cilia can be maintained dynamically.
Exceptions where IFT is not present include Plasmodium falciparum which is one of the species of Plasmodium that cause malaria in humans. In this parasite, cilia assemble in the cytoplasm.[3]
# Cilium-related disease
File:Eukaryotic cilium diagram en.svg
Ciliary defects can lead to several human diseases. Genetic mutations compromising the proper functioning of cilia can cause chronic disorders such as primary ciliary dyskinesia (PCD). In addition, a defect of the primary cilium in the renal tube cells can lead to polycystic kidney disease (PKD). In another genetic disorder called Bardet-Biedl syndrome (BBS), the mutant gene products are the components in the basal body and cilia.
Lack of functional cilia in mammalian Fallopian tubes can cause ectopic pregnancy. A fertilized ovum may not reach the uterus if the cilia are unable to move it there. In such a case, the ovum will implant in the Fallopian tubes, causing a tubal pregnancy, the most common form of ectopic pregnancy.
Since the flagellum of human sperm is actually a modified cilium, ciliary dysfunction can also be responsible for male infertility.[4]
Of interest, there is an association of primary ciliary dyskinesia with left-right anatomic abnormalities such as situs inversus (a combination of findings known as Kartagener's syndrome) and other heterotaxic defects. These left-right anatomic abnormalities can also result in congenital heart disease[5]. In fact, it has been shown that proper cilial function is responsible for the normal left-right asymmetry in mammals.[6] | https://www.wikidoc.org/index.php/Cilia | |
cf6ef49144be29e9046de73d051976aa92ad7452 | wikidoc | Citral | Citral
Citral, or 3,7-dimethyl-2,6-octadienal or lemonal, is either of a pair of terpenoids with the molecular formula C10H16O. The two compounds are double bond isomers. The trans isomer is known as geranial or citral A. The cis isomer is known as neral or citral B.
Geranial has a strong lemon odor. Neral has a lemon odor that is less intense, but sweeter. Citral is therefore an aroma compound used in perfumery for its citrus effect. Citral is also used as a flavor and for fortifying lemon oil. It also has strong anti-microbial qualities, and pheromonal effects in insects.
Citral is used in the synthesis of vitamin A, ionone, and methylionone.
Citral is present in the oils of several plants, including lemon myrtle (90-95%), Litsea cubeba (70-85%), lemongrass (65-85%), Lemon verbena (30-35%), lemon balm, lemon and orange.
# Health & Safety information
Citral should be avoided by people with perfume allergy. | Citral
Citral, or 3,7-dimethyl-2,6-octadienal or lemonal, is either of a pair of terpenoids with the molecular formula C10H16O. The two compounds are double bond isomers. The trans isomer is known as geranial or citral A. The cis isomer is known as neral or citral B.
Geranial has a strong lemon odor. Neral has a lemon odor that is less intense, but sweeter. Citral is therefore an aroma compound used in perfumery for its citrus effect. Citral is also used as a flavor and for fortifying lemon oil. It also has strong anti-microbial qualities[1], and pheromonal effects in insects.[2][3]
Citral is used in the synthesis of vitamin A, ionone, and methylionone.
Citral is present in the oils of several plants, including lemon myrtle (90-95%), Litsea cubeba (70-85%), lemongrass (65-85%), Lemon verbena (30-35%), lemon balm, lemon and orange.[4]
# Health & Safety information
Citral should be avoided by people with perfume allergy[5]. | https://www.wikidoc.org/index.php/Citral | |
c181c6c326fa10b87b7c290d51c849f55a3ebb21 | wikidoc | Citrin | Citrin
Citrin also known as solute carrier family 25, member 13 (citrin) or SLC25A13 is a protein which in humans is encoded by the SLC25A13 gene.
Citrin is associated with type II citrullinemia and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD).
The term Citrin when referring to Vitamin-P was the most active Bio-flavonoid in lemons, it was found to be Eriodictyol (but a more active form constituent was found there decades later). | Citrin
Citrin also known as solute carrier family 25, member 13 (citrin) or SLC25A13 is a protein which in humans is encoded by the SLC25A13 gene.[1]
Citrin is associated with type II citrullinemia[2][3][4] and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD).
The term Citrin when referring to Vitamin-P was the most active Bio-flavonoid in lemons, it was found to be Eriodictyol (but a more active form constituent was found there decades later). | https://www.wikidoc.org/index.php/Citrin | |
f607180bbbe993b7420705908b47a544d84072b2 | wikidoc | Clalit | Clalit
Clalit (Template:Lang-he, lit. General) is one of Israel's leading HMOs. It was founded in 1911 by a group of 150 immigrants desiring a mutual aid health care association. When the State of Israel was founded in 1948, Clalit helped in the restructuring of Israel's health care system to provide for the huge wave of new immigrants. Nowadays there are Clalit clinics in almost every neighborhood in the country.
# Currently
In January, 1995 Israel's national health insurance law went into effect, creating a compulsory health care system based on four service providers; Clalit, Leumit, Maccabi, and Meuhedet. Clalit is the largest of the four with around 3.8 million insured members, 60% of the Israeli population.
Clalit runs its own network of hospitals throughout Israel. It has a total of 14 hospitals, including psychiatric hospitals, and a rehabilitation hospital, all of which are university-affiliated. It also runs 1,200 primary and specialized clinics and has a network of pharmacies and dental clinics.
## Clalit-run hospitals
- Rabin Medical Center – Beilinson Campus (founded in 1938) in Petah Tikva. Among its specialities are open-heart surgery and neurosurgery, as well as heart, liver and kidney transplants.
- Rabin Medical Center – Golda Campus (founded in 1942) in Petah Tikva. Among its specialities are total joint replacement, home dialysis, vascular surgery, and hematology research using electromicroscopic techniques.
- Lady Davis Hospital (founded in 1967) in Haifa. It is part of the modern Carmel Medical Center. and provides comprehensive healthcare to the heterogeneous inhabitants of Haifa, its suburbs and points north. Among its specialities are its Cardiology, Cardiovascular and Thoracic Surgery Departments, as well as its Community and Medicine Epidemiology Department.
- HaEmek Hospital (founded in 1930)in Afula. It is part of the HaEmek Valley Medical Center. It specializes in the treatment of fertility and reproductive problems.
- Meir Hospital (founded in 1960) in Kfar Saba. It is part of the Sapir Medical Center. It specializes in its treatment of pulmonary diseases and spinal surgery.
- Kaplan Medical Center (founded in 1953) in Rehovot. It is known for its expertise in hand surgery.
- Soroka Hospital (founded in 1960) in Beersheba, the major hospital in the Negev region.
- Yoseftal Hospital (founded in 1968) in Eilat. It is part of the Yoseftal Medical Center. It is Israel’s southernmost hospital.
# Criticism of Clalit-run hospitals
In March 2007, Prof. Gabi Barabash, director of Tel Aviv's Ichilov Hospital criticised the Israeli Health Ministry for allowing Clalit to run private hospitals. He claims that it would be a disaster for the public hospitalization system. Ruth Ralbag, a senior official in the Health Ministry's budget department, argues that the incentives for opening private hospitals lead to a decline in the public health system and the division of health consumers into rich and poor. | Clalit
Clalit (Template:Lang-he, lit. General) is one of Israel's leading HMOs. It was founded in 1911 by a group of 150 immigrants desiring a mutual aid health care association. When the State of Israel was founded in 1948, Clalit helped in the restructuring of Israel's health care system to provide for the huge wave of new immigrants. Nowadays there are Clalit clinics in almost every neighborhood in the country.
# Currently
In January, 1995 Israel's national health insurance law went into effect, creating a compulsory health care system based on four service providers; Clalit, Leumit, Maccabi, and Meuhedet. Clalit is the largest of the four with around 3.8 million insured members, 60% of the Israeli population.
Clalit runs its own network of hospitals throughout Israel. It has a total of 14 hospitals, including psychiatric hospitals, and a rehabilitation hospital, all of which are university-affiliated.[1] It also runs 1,200 primary and specialized clinics and has a network of pharmacies and dental clinics.
## Clalit-run hospitals
- Rabin Medical Center – Beilinson Campus (founded in 1938) in Petah Tikva. Among its specialities are open-heart surgery and neurosurgery, as well as heart, liver and kidney transplants.
- Rabin Medical Center – Golda Campus (founded in 1942) in Petah Tikva. Among its specialities are total joint replacement, home dialysis, vascular surgery, and hematology research using electromicroscopic techniques.
- Lady Davis Hospital (founded in 1967) in Haifa. It is part of the modern Carmel Medical Center. and provides comprehensive healthcare to the heterogeneous inhabitants of Haifa, its suburbs and points north. Among its specialities are its Cardiology, Cardiovascular and Thoracic Surgery Departments, as well as its Community and Medicine Epidemiology Department.
- HaEmek Hospital (founded in 1930)in Afula. It is part of the HaEmek Valley Medical Center. It specializes in the treatment of fertility and reproductive problems.
- Meir Hospital (founded in 1960) in Kfar Saba. It is part of the Sapir Medical Center. It specializes in its treatment of pulmonary diseases and spinal surgery.
- Kaplan Medical Center (founded in 1953) in Rehovot. It is known for its expertise in hand surgery.
- Soroka Hospital (founded in 1960) in Beersheba, the major hospital in the Negev region.
- Yoseftal Hospital (founded in 1968) in Eilat. It is part of the Yoseftal Medical Center. It is Israel’s southernmost hospital. [2]
# Criticism of Clalit-run hospitals
In March 2007, Prof. Gabi Barabash, director of Tel Aviv's Ichilov Hospital criticised the Israeli Health Ministry for allowing Clalit to run private hospitals. He claims that it would be a disaster for the public hospitalization system. Ruth Ralbag, a senior official in the Health Ministry's budget department, argues that the incentives for opening private hospitals lead to a decline in the public health system and the division of health consumers into rich and poor. [3] | https://www.wikidoc.org/index.php/Clalit | |
9ae8f757772bf4b6299c394f3c4b70c4dc5b8998 | wikidoc | Clinic | Clinic
A clinic or outpatient clinic are originally small private or public health facility that provide health care for ambulatory patients or clients in a community, in contrast to inpatients treated in a hospital. Some grow to be institutions as large as major hospitals, whilst retaining the name Clinic. General practice clinics are run by one or more general practitioners or practice managers. Physiotherapy clinics are usually operated by physiotherapists and psychology clinics by clinical psychologists, and so on for each health profession. Some clinics are operated in-house by employers, government organizations or hospitals and some clinical services are outsourced to private corporations, specialising in provision of health services. In China, for example, owners of those clinics do not have formal medical education. Health care in India, China, Russia and Africa is provided to vast rural areas by mobile health clinics or roadside dispensaries, some of which integrate traditional health practices. In India these traditional clinics provide ayurvedic medicine and unani herbal medical practice. In each of these countries traditional medicine tends to be an hereditary practice.
The function of clinics will differ from country to country. For instance, a local general practice run by a single general practitioner will provide primary health care and will usually be run as a for-profit business by the owner whereas a government specialist clinic may provide subsidized specialized health care.
Some clinics function as a place for people with injuries or illnesses to come and be seen by triage nurse or other health worker. In these clinics, the injury or illness may not be serious enough to warrant a visit to an emergency room, but the person can be moved to one if required. Treatment at these clinics is often less expensive than it would be at a casualty department. Also, unlike an ER these clinics are often not open on a 24 x 7 x 365 basis. They sometimes have access to diagnostic equipment such as X-ray machines, especially if the clinic is part of a larger facility. Doctors at such clinics can often refer patients to specialists if the need arises.
# Etymology
The word derives from the Greek klinein meaning to slope, lean or recline. Hence kline a couch or bed, klinikos sloping or reclining and to Latin clinicus . An early use of the word clinic was, 'one who receives baptism on a sick bed' . Psychoanalytic clinics tradtionally have the patient reclining on a couch to undergo analysis.
# Types of clinics
- In the United States, a free clinic provides free or low cost health care for those without insurance.
- A Retail Based Clinic is housed in supermarkets and similar retail outlets providing walk in health care, which may be staffed by nurse practitioners.
- A general out-patient clinic is a clinic offering a community general diagnoses or treatments without an overnight stay.
- A polyclinic is a clinic, hospital, or school where many diseases are treated and studied.
- A fertility clinic aims to help those couples and individuals to become pregnant. An abortion clinic is a medical facility providing certain kinds of outpatient medical care, including abortion to women. Such clinics may be public medical centers or private medical practices.
- A specialist clinic is a clinic with in-depth diagnosis or treatment on diseases of specific parts of the body. This type of clinic contrasts with general out-patient clinics, which deal with general diseases.
# Examples of clinics
- Tavistock Clinic part of the Britain NHS, was founded in 1920's one of its most celebrated members was R D Laing.
- San Francisco's Suitcase Clinic is a prime example of a free clinic.
- Christian Medical College & Hospital in Vellore, India has extensive roadside dispensaries and began as a one bed clinic in 1900.
- The Edmonton Clinic is a joint venture of the University of Alberta and a government health care body Capital health, expected to be completed in 2011.
- The Shyness Clinic founded by Zimbardo to assist those disabled by public or private shyness.
- La Borde clinic in the Loire valley France, is an innovative psychiatric clinic where patients are liberated to actively participate in the running the facility.
- The Mayo Clinic and Cleveland Clinic are two comprehensive health care systems. Both began as much smaller group practices that have grown into large medical programs in the United States, whilst retaining their names.
# Issues
## Show rate for appointments
The no-show rate for clinics is about 23% to 15%.
A common reason for now showing for an appointment is the patient's forgetting they have an appointment.
Regarding predictors of no show rates;
- Patient characteristics:
Younger patiients
Minority demographics
Lower socioeconomic status
- Younger patiients
- Minority demographics
- Lower socioeconomic status
- Appointment characteristics:
Appointment lead time (time interval between the date when the appointment is made and the actual appointment date) is the most important factor. Lead time intervals greater than 3 days increase the rate of no-show
Prior missed appointments by the patient
- Appointment lead time (time interval between the date when the appointment is made and the actual appointment date) is the most important factor. Lead time intervals greater than 3 days increase the rate of no-show
- Prior missed appointments by the patient
- Clinic characteristics
Patients' relations with clinic staff
Patients' sense of belonging
- Patients' relations with clinic staff
- Patients' sense of belonging
Interventions in high-risk populations have reduced show rates to:
- 7% (started at 10%) | Clinic
A clinic or outpatient clinic are originally small private or public health facility that provide health care for ambulatory patients or clients in a community, in contrast to inpatients treated in a hospital. Some grow to be institutions as large as major hospitals, whilst retaining the name Clinic. General practice clinics are run by one or more general practitioners or practice managers. Physiotherapy clinics are usually operated by physiotherapists and psychology clinics by clinical psychologists, and so on for each health profession. Some clinics are operated in-house by employers, government organizations or hospitals and some clinical services are outsourced to private corporations, specialising in provision of health services. In China, for example, owners of those clinics do not have formal medical education. Health care in India, China, Russia and Africa is provided to vast rural areas by mobile health clinics or roadside dispensaries, some of which integrate traditional health practices. In India these traditional clinics provide ayurvedic medicine and unani herbal medical practice. In each of these countries traditional medicine tends to be an hereditary practice.
The function of clinics will differ from country to country. For instance, a local general practice run by a single general practitioner will provide primary health care and will usually be run as a for-profit business by the owner whereas a government specialist clinic may provide subsidized specialized health care.
Some clinics function as a place for people with injuries or illnesses to come and be seen by triage nurse or other health worker. In these clinics, the injury or illness may not be serious enough to warrant a visit to an emergency room, but the person can be moved to one if required. Treatment at these clinics is often less expensive than it would be at a casualty department. Also, unlike an ER these clinics are often not open on a 24 x 7 x 365 basis. They sometimes have access to diagnostic equipment such as X-ray machines, especially if the clinic is part of a larger facility. Doctors at such clinics can often refer patients to specialists if the need arises.
# Etymology
The word derives from the Greek klinein meaning to slope, lean or recline. Hence kline a couch or bed, klinikos sloping or reclining and to Latin clinicus [1]. An early use of the word clinic was, 'one who receives baptism on a sick bed' [2]. Psychoanalytic clinics tradtionally have the patient reclining on a couch to undergo analysis.
# Types of clinics
- In the United States, a free clinic provides free or low cost health care for those without insurance.
- A Retail Based Clinic is housed in supermarkets and similar retail outlets providing walk in health care, which may be staffed by nurse practitioners.
- A general out-patient clinic is a clinic offering a community general diagnoses or treatments without an overnight stay.
- A polyclinic is a clinic, hospital, or school where many diseases are treated and studied.
- A fertility clinic aims to help those couples and individuals to become pregnant. An abortion clinic is a medical facility providing certain kinds of outpatient medical care, including abortion to women. Such clinics may be public medical centers or private medical practices.
- A specialist clinic is a clinic with in-depth diagnosis or treatment on diseases of specific parts of the body. This type of clinic contrasts with general out-patient clinics, which deal with general diseases.
# Examples of clinics
- Tavistock Clinic part of the Britain NHS, was founded in 1920's one of its most celebrated members was R D Laing.
- San Francisco's Suitcase Clinic is a prime example of a free clinic.
- Christian Medical College & Hospital in Vellore, India has extensive roadside dispensaries and began as a one bed clinic in 1900.
- The Edmonton Clinic is a joint venture of the University of Alberta and a government health care body Capital health, expected to be completed in 2011.
- The Shyness Clinic founded by Zimbardo to assist those disabled by public or private shyness.
- La Borde clinic in the Loire valley France, is an innovative psychiatric clinic where patients are liberated to actively participate in the running the facility.
- The Mayo Clinic and Cleveland Clinic are two comprehensive health care systems. Both began as much smaller group practices that have grown into large medical programs in the United States, whilst retaining their names.
# Issues
## Show rate for appointments
The no-show rate for clinics is about 23%[3] to 15%[4].
A common reason for now showing for an appointment is the patient's forgetting they have an appointment[5].
Regarding predictors of no show rates;
- Patient characteristics[3]:
Younger patiients
Minority demographics
Lower socioeconomic status
- Younger patiients
- Minority demographics
- Lower socioeconomic status
- Appointment characteristics[3]:
Appointment lead time (time interval between the date when the appointment is made and the actual appointment date) is the most important factor. Lead time intervals greater than 3 days increase the rate of no-show[6]
Prior missed appointments by the patient
- Appointment lead time (time interval between the date when the appointment is made and the actual appointment date) is the most important factor. Lead time intervals greater than 3 days increase the rate of no-show[6]
- Prior missed appointments by the patient
- Clinic characteristics
Patients' relations with clinic staff[7]
Patients' sense of belonging[7]
- Patients' relations with clinic staff[7]
- Patients' sense of belonging[7]
Interventions in high-risk populations have reduced show rates to:
- 18%[8]
- 15%[9]
- 7% (started at 10%)[6] | https://www.wikidoc.org/index.php/Clinic | |
46162c53aab26febf89282faa4200bd1bbbc43d7 | wikidoc | Cloves | Cloves
Cloves (Syzygium aromaticum, syn. Eugenia aromaticum or Eugenia caryophyllata) are the aromatic dried flower buds of a tree in the family Myrtaceae. Cloves are native to Indonesia and used as a spice in cuisine all over the world. The name derives from French clou, a nail, as the buds vaguely resemble small irregular nails in shape. Cloves are harvested primarily in Zanzibar, Indonesia and Madagascar; it is also grown in Pakistan, India, and Sri Lanka.
The clove tree is an evergreen which grows to a height ranging from 10-20 m, having large oval leaves and crimson flowers in numerous groups of terminal clusters. The flower buds are at first of a pale color and gradually become green, after which they develop into a bright red, when they are ready for collecting. Cloves are harvested when 1.5-2 cm long, and consist of a long calyx, terminating in four spreading sepals, and four unopened petals which form a small ball in the centre.
# Uses
According to FAO, Indonesia produced almost 80% of the world's clove output in 2005 followed at a distance by Madagascar and Tanzania.
Cloves can be used in cooking either whole or in a ground form, but as they are extremely strong, they are used sparingly. The spice is used throughout Europe and Asia and is smoked in a type of cigarettes locally known as kretek in Indonesia. Cloves are also an important incense material in Chinese and Japanese culture.
Cloves have historically been used in Indian cuisine (both North Indian and South Indian) as well as in Mexican cuisine, where it is often paired together with cumin and cinnamon. In the north Indian cuisine, it is used in almost every sauce or side dish made, mostly ground up along with other spices. They are also a key ingredient in tea along with green cardamoms. In the south Indian cuisine, it finds extensive use in the biryani dish (similar to the pilaf, but with the addition of local spice taste), and is normally added whole to enhance the presentation and flavor of the rice.
# Medicinal uses
Cloves are used in Ayurveda called Lavang in India, Chinese medicine and western herbalism and dentistry where the essential oil is used as an anodyne (painkiller) for dental emergencies. Cloves are used as a carminative, to increase hydrochloric acid in the stomach and to improve peristalsis. Cloves are also said to be a natural antihelmintic. The essential oil is used in aromatherapy when stimulation and warming is needed, especially for digestive problems. Topical application over the stomach or abdomen will warm the digestive tract.
In Chinese medicine cloves or ding xiang are considered acrid, warm and aromatic, entering the kidney, spleen and stomach meridians, and are notable in their ability to warm the middle, direct stomach qi downward, to treat hiccough and to fortify the kidney yang. Because the herb is so warming it is contraindicated in any persons with fire symptoms and according to classical sources should not be used for anything except cold from yang deficiency. As such it is used in formulas for impotence or clear vaginal discharge from yang deficiency, for morning sickness together with ginseng and patchouli, or for vomiting and diarrhea due to spleen and stomach coldness. This would translate to hypochlorhydria.
Ayurvedic herbalist K.P. Khalsa, RH (AHG), uses cloves internally as a tea and topically as an oil for hypotonic muscles, including for multiple sclerosis. This is also found in Tibetan medicine. Ayurvedic herbalist Alan Tilotson, RH (AHG) suggests avoiding more than occasional use of cloves internally in the presence of pitta inflammation such as is found in acute flares of autoimmune diseases.
In West Africa, the Yorubas use cloves infused in water as a treatment for stomach upsets, vomitting and diarrhoea.The infusion is called Ogun Jedi-jedi.
Western studies have supported the use of cloves and clove oil for dental pain, and to a lesser extent for fever reduction, as a mosquito repellent and to prevent premature ejaculation. Clove may reduce blood sugar levels.
# Toxicity
Large amounts should be avoided in pregnancy.
Cloves can be irritating to the gastrointestinal tract, and should be avoided by people with gastric ulcers, colitis, or irritable bowel syndrome. In overdoses, cloves can cause vomiting, nausea, diarrhea, and upper gastrointestinal hemorrhage.
Severe cases can lead to changes in liver function, dyspnea, loss of consciousness, hallucination, and even death. The internal use of the essential oil should be restricted to 3 drops per day for an adult as excessive use can cause severe kidney damage.
# History
Until modern times, cloves grew only on a few islands in the Maluku Islands (historically called the Spice Islands), including Bacan, Makian, Moti, Ternate, and Tidore. Nevertheless, they found their way west to the Middle East and Europe well before the first century CE. Archeologists found cloves within a ceramic vessel in Syria along with evidence dating the find to within a few years of 1721 BC.
Cloves, along with nutmeg and pepper, were highly prized in Roman times, and Pliny the Elder once famously complained that "there is no year in which India does not drain the Roman Empire of fifty million sesterces". Cloves were traded by Arabs during the Middle Ages in the profitable Indian Ocean trade. In the late fifteenth century, Portugal took over the Indian Ocean trade, including cloves, due to the Treaty of Tordesillas with Spain and a separate treaty with the sultan of Ternate. The Portuguese brought large quantities of cloves to Europe, mainly from the Maluku Islands. Clove was then one of the most valuable spices, a kg costing around 7 g of gold.
The trade later became dominated by the Dutch in the seventeenth century. With great difficulty the French succeeded in introducing the clove tree into Mauritius in the year 1770; subsequently their cultivation was introduced into Guiana, Brazil, most of the West Indies, and Zanzibar, where the majority of cloves are grown today.
In Britain in the seventeenth and eighteenth centuries, cloves were worth at least their weight in gold, due to the high price of importing them.
The clove has become a commercial 'success', with products including clove drops being released and enjoyed by die-hard clove fans.
# Active compounds
The compound responsible for the cloves' aroma is eugenol. It is the main component in the essential oil extracted from cloves, comprising 72-90%. Eugenol has pronounced antiseptic and anaesthetic properties. Other important constituents include essential oils acetyl eugenol, beta-caryophylline and vanillin; crategolic acid; tannins, gallotannic acid, methyl salicylate (painkiller); the flavanoids eugenin, kaempferol, rhamnetin, and eugenitin; triterpenoids like oleanolic acid, stigmasterol and campesterol; and several sesquiterpenes.
# Notes and references
- ↑ Dorenburg, Andrew and Page, Karen. "The New American Chef: Cooking with the Best Flavors and Techniques from Around the World", John Wiley and Sons Inc., ©2003.
- ↑ Balch, Phyllis and Balch, James. Prescription for Nutritional Healing, 3rd ed., Avery Publishing, ©2000, pg. 94.
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble 2004
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble 2004
- ↑ TibetMed - Question: Multiple Sclerosis
- ↑ Tilotson, Alan. Special Diets for Illness
- ↑ National Institutes of Health, Medicine Plus. Clove (Eugenia aromatica) and Clove oil (Eugenol)
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble 2004
- ↑ Jump up to: 9.0 9.1 Turner, Jack (2004). Spice: The History of a Temptation. Vintage Books. pp. p. xv. ISBN 0-375-70705-0.CS1 maint: Extra text (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble. 2004
bg:Карамфил (подправка)
ca:Clavell d'espècia
cs:Hřebíček
co:Viulaccia
de:Gewürznelke
el:Γαριφαλόδενδρο
et:Nelk_(vürts)
eo:Kariofilo
id:Cengkeh
it:Eugenia caryophyllata
he:ציפורן (תבלין)
ht:Jiwòf
la:Syzygium aromaticum
lb:Neelcheskapp
lt:Kvapnusis gvazdikmedis
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ta:கிராம்பு
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wa:Djirofe | Cloves
Cloves (Syzygium aromaticum, syn. Eugenia aromaticum or Eugenia caryophyllata) are the aromatic dried flower buds of a tree in the family Myrtaceae. Cloves are native to Indonesia and used as a spice in cuisine all over the world. The name derives from French clou, a nail, as the buds vaguely resemble small irregular nails in shape. Cloves are harvested primarily in Zanzibar, Indonesia and Madagascar; it is also grown in Pakistan, India, and Sri Lanka.
The clove tree is an evergreen which grows to a height ranging from 10-20 m, having large oval leaves and crimson flowers in numerous groups of terminal clusters. The flower buds are at first of a pale color and gradually become green, after which they develop into a bright red, when they are ready for collecting. Cloves are harvested when 1.5-2 cm long, and consist of a long calyx, terminating in four spreading sepals, and four unopened petals which form a small ball in the centre.
# Uses
According to FAO, Indonesia produced almost 80% of the world's clove output in 2005 followed at a distance by Madagascar and Tanzania.
Cloves can be used in cooking either whole or in a ground form, but as they are extremely strong, they are used sparingly. The spice is used throughout Europe and Asia and is smoked in a type of cigarettes locally known as kretek in Indonesia. Cloves are also an important incense material in Chinese and Japanese culture.
Cloves have historically been used in Indian cuisine (both North Indian and South Indian) as well as in Mexican cuisine, where it is often paired together with cumin and cinnamon.[1] In the north Indian cuisine, it is used in almost every sauce or side dish made, mostly ground up along with other spices. They are also a key ingredient in tea along with green cardamoms. In the south Indian cuisine, it finds extensive use in the biryani dish (similar to the pilaf, but with the addition of local spice taste), and is normally added whole to enhance the presentation and flavor of the rice.
# Medicinal uses
Cloves are used in Ayurveda called Lavang in India, Chinese medicine and western herbalism and dentistry where the essential oil is used as an anodyne (painkiller) for dental emergencies. Cloves are used as a carminative, to increase hydrochloric acid in the stomach and to improve peristalsis. Cloves are also said to be a natural antihelmintic.[2] The essential oil is used in aromatherapy when stimulation and warming is needed, especially for digestive problems. Topical application over the stomach or abdomen will warm the digestive tract.
In Chinese medicine cloves or ding xiang are considered acrid, warm and aromatic, entering the kidney, spleen and stomach meridians, and are notable in their ability to warm the middle, direct stomach qi downward, to treat hiccough and to fortify the kidney yang.[3] Because the herb is so warming it is contraindicated in any persons with fire symptoms and according to classical sources should not be used for anything except cold from yang deficiency. As such it is used in formulas for impotence or clear vaginal discharge from yang deficiency, for morning sickness together with ginseng and patchouli, or for vomiting and diarrhea due to spleen and stomach coldness.[4] This would translate to hypochlorhydria.
Ayurvedic herbalist K.P. Khalsa, RH (AHG), uses cloves internally as a tea and topically as an oil for hypotonic muscles, including for multiple sclerosis. This is also found in Tibetan medicine.[5] Ayurvedic herbalist Alan Tilotson, RH (AHG) suggests avoiding more than occasional use of cloves internally in the presence of pitta inflammation such as is found in acute flares of autoimmune diseases.[6]
In West Africa, the Yorubas use cloves infused in water as a treatment for stomach upsets, vomitting and diarrhoea.The infusion is called Ogun Jedi-jedi.
Western studies have supported the use of cloves and clove oil for dental pain, and to a lesser extent for fever reduction, as a mosquito repellent and to prevent premature ejaculation. Clove may reduce blood sugar levels.[7]
# Toxicity
Large amounts should be avoided in pregnancy.[citation needed]
Cloves can be irritating to the gastrointestinal tract, and should be avoided by people with gastric ulcers, colitis, or irritable bowel syndrome. In overdoses, cloves can cause vomiting, nausea, diarrhea, and upper gastrointestinal hemorrhage.[citation needed]
Severe cases can lead to changes in liver function, dyspnea, loss of consciousness, hallucination, and even death.[8] The internal use of the essential oil should be restricted to 3 drops per day for an adult as excessive use can cause severe kidney damage.[citation needed]
# History
Until modern times, cloves grew only on a few islands in the Maluku Islands (historically called the Spice Islands), including Bacan, Makian, Moti, Ternate, and Tidore.[9] Nevertheless, they found their way west to the Middle East and Europe well before the first century CE. Archeologists found cloves within a ceramic vessel in Syria along with evidence dating the find to within a few years of 1721 BC.[9]
Cloves, along with nutmeg and pepper, were highly prized in Roman times, and Pliny the Elder once famously complained that "there is no year in which India does not drain the Roman Empire of fifty million sesterces". Cloves were traded by Arabs during the Middle Ages in the profitable Indian Ocean trade. In the late fifteenth century, Portugal took over the Indian Ocean trade, including cloves, due to the Treaty of Tordesillas with Spain and a separate treaty with the sultan of Ternate. The Portuguese brought large quantities of cloves to Europe, mainly from the Maluku Islands. Clove was then one of the most valuable spices, a kg costing around 7 g of gold[citation needed].
The trade later became dominated by the Dutch in the seventeenth century. With great difficulty the French succeeded in introducing the clove tree into Mauritius in the year 1770; subsequently their cultivation was introduced into Guiana, Brazil, most of the West Indies, and Zanzibar, where the majority of cloves are grown today.
In Britain in the seventeenth and eighteenth centuries, cloves were worth at least their weight in gold, due to the high price of importing them.[citation needed]
The clove has become a commercial 'success', with products including clove drops being released and enjoyed by die-hard clove fans.
# Active compounds
The compound responsible for the cloves' aroma is eugenol. It is the main component in the essential oil extracted from cloves, comprising 72-90%. Eugenol has pronounced antiseptic and anaesthetic properties. Other important constituents include essential oils acetyl eugenol, beta-caryophylline and vanillin; crategolic acid; tannins, gallotannic acid, methyl salicylate (painkiller); the flavanoids eugenin, kaempferol, rhamnetin, and eugenitin; triterpenoids like oleanolic acid, stigmasterol and campesterol; and several sesquiterpenes.[10]
# Notes and references
- ↑ Dorenburg, Andrew and Page, Karen. "The New American Chef: Cooking with the Best Flavors and Techniques from Around the World", John Wiley and Sons Inc., ©2003.
- ↑ Balch, Phyllis and Balch, James. Prescription for Nutritional Healing, 3rd ed., Avery Publishing, ©2000, pg. 94.
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble 2004
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble 2004
- ↑ TibetMed - Question: Multiple Sclerosis
- ↑ http://oneearthherbs.squarespace.com/diseases/special-diets-for-illness.html Tilotson, Alan. Special Diets for Illness
- ↑ http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-clove.html National Institutes of Health, Medicine Plus. Clove (Eugenia aromatica) and Clove oil (Eugenol)
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble 2004
- ↑ Jump up to: 9.0 9.1 Turner, Jack (2004). Spice: The History of a Temptation. Vintage Books. pp. p. xv. ISBN 0-375-70705-0.CS1 maint: Extra text (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("https://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
- ↑ Chinese Herbal Medicine: Materia Medica, Third Edition by Dan Bensky, Steven Clavey, Erich Stoger, and Andrew Gamble. 2004
Template:Herbs & spices
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el:Γαριφαλόδενδρο
et:Nelk_(vürts)
eo:Kariofilo
id:Cengkeh
it:Eugenia caryophyllata
he:ציפורן (תבלין)
ht:Jiwòf
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b4603c717e92cdc9af92b49702b6b4c2040e0a2e | wikidoc | Cobalt | Cobalt
# Overview
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought by alchemists to be due to the known metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue-pigment producing minerals; they were named because they were poor in known metals and gave poisonous arsenic-containing fumes upon smelting. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the kobold.
Today, some cobalt is produced specifically from various metallic-lustered ores, for example cobaltite (CoAsS), but the main source of the element is as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo and Zambia yields most of the cobalt mined worldwide.
Cobalt is primarily used as the metal, in the preparation of magnetic, wear-resistant and high-strength alloys. Its compounds cobalt silicate and cobalt(II) aluminate (CoAl2O4, cobalt blue) give a distinctive deep blue color to glass, smalt, ceramics, inks, paints and varnishes. Cobalt occurs naturally as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high intensity gamma rays.
Cobalt is the active center of coenzymes called cobalamins, the most common example of which is ]. As such it is an essential trace dietary mineral for all animals. Cobalt in inorganic form is also an active nutrient for bacteria, algae and fungi.
# Characteristics
Cobalt is a ferromagnetic metal with a specific gravity of 8.9. Pure cobalt is not found in nature, but compounds of cobalt are common. Small amounts of it are found in most rocks, soil, plants, and animals. The Curie temperature is 1115 °C and the magnetic moment is 1.6–1.7 Bohr magnetons per atom. In nature, it is frequently associated with nickel, and both are characteristic minor components of meteoric iron. Cobalt has a relative permeability two thirds that of iron. Metallic cobalt occurs as two crystallographic structures: hcp and fcc. The ideal transition temperature between the hcp and fcc structures is 450 °C, but in practice, the energy difference is so small that random intergrowth of the two is common.
Cobalt is a weakly reducing metal that is protected from oxidation by a passivating oxide film. It is attacked by halogens and sulfur. Heating in oxygen produces Co3O4 which loses oxygen at 900 °C to give the monoxide CoO. The metal reacts with Fluorine gas (F2) at 520 K to give CoF3, with chlorine (Cl2), bromine (Br2) and iodine (I2), the corresponding binary halides formed. It has no reaction with hydrogen gas (H2) or nitrogen gas (N2) even when heated, but it does react with boron, carbon, phosphorus, arsenic and sulphur. At ordinary temperatures, it reacts slowly with mineral acids, and very slowly with moist air, but not with dry air.
# Compounds
Common oxidation states of cobalt include +2 and +3, although compounds with oxidation states ranging from −3 to +4 are also known. A common oxidation state for simple compounds is +2. Cobalt(II) salts form the red-pink 2+ complex in aqueous solution. Addition of chloride gives the intensely blue 2−.
## Oxygen and chalcogen compounds
Several oxides of cobalt are known. Green cobalt(II) oxide (CoO) has rocksalt structure. It is readily oxidized with water and oxygen to brown cobalt(III) hydroxide (Co(OH)3). At temperatures of 600–700 °C, CoO oxidizes to the blue cobalt(II,III) oxide (Co3O4), which has a spinel structure. Black cobalt(III) oxide (Co2O3) is also known. Cobalt oxides are antiferromagnetic at low temperature: CoO (Neel temperature 291 K) and Co3O4 (Neel temperature: 40 K), which is analogous to magnetite (Fe3O4), with a mixture of +2 and +3 oxidation states.
The principal chalcogenides of cobalt include the black cobalt(II) sulfides, CoS2, which adopts a pyrite-like structure, and Co2S3. Pentlandite (Co9S8) is metal-rich.
## Halides
Four dihalides of cobalt(II) are known: cobalt(II) fluoride (CoF2, pink), cobalt(II) chloride (CoCl2, blue), cobalt(II) bromide (CoBr2, green), cobalt(II) iodide (CoI2, blue-black). These halides exist in anhydrous and hydrated forms. Whereas the anhydrous dichloride is blue, the hydrate is red.
The reduction potential for the reaction
is +1.92 V, beyond that for chlorine to chloride, +1.36 V. As a consequence cobalt(III) and chloride would result in the cobalt(III) being reduced to cobalt(II). Because the reduction potential for fluorine to fluoride is so high, +2.87 V, cobalt(III) fluoride is one of the few simple stable cobalt(III) compounds. Cobalt(III) fluoride, which is used in some fluorination reactions, reacts vigorously with water.
## Coordination compounds
As for all metals, molecular compounds of cobalt are classified as coordination complexes, that is molecules or ions that contain cobalt linked to several ligands. The principles of electronegativity and hardness–softness of a series of ligands can be used to explain the usual oxidation state of the cobalt. For example Co+3 complexes tend to have ammine ligands. As phosphorus is softer than nitrogen, phosphine ligands tend to feature the softer Co2+ and Co+, an example being tris(triphenylphosphine)cobalt(I) chloride ((P(C6H5)3)3CoCl). The more electronegative (and harder) oxide and fluoride can stabilize Co4+ and Co5+ derivatives, e.g. caesium hexafluorocobaltate (Cs2CoF6) and potassium percobaltate (K3CoO4).
Alfred Werner, a Nobel-prize winning pioneer in coordination chemistry, worked with compounds of empirical formula CoCl3(NH3)6. One of the isomers determined was cobalt(III) hexammine chloride. This coordination complex, a "typical" Werner-type complex, consists of a central cobalt atom coordinated by six ammine ligands orthogonal to each other and three chloride counteranions. Using chelating ethylenediamine ligands in place of ammonia gives tris(ethylenediamine)cobalt(III) chloride (Cl3), which was one of the first coordination complexes that was resolved into optical isomers. The complex exists as both either right- or left-handed forms of a "three-bladed propeller". This complex was first isolated by Werner as yellow-gold needle-like crystals.
## Organometallic compounds
Cobaltocene is a structural analog to ferrocene, where cobalt substitutes for iron. Cobaltocene is sensitive to oxidation, much more than ferrocene. Cobalt carbonyl (Co2(CO)8) is a catalyst in carbonylation reactions. Vitamin BTemplate:Ssub (see below) is an organometallic compound found in nature and is the only vitamin to contain a metal atom.
# Isotopes
59Co is the only stable cobalt isotope and the only isotope to exist naturally on Earth. 22 radioisotopes have been characterized with the most stable being 60Co with a half-life of 5.2714 years, 57Co with a half-life of 271.79 days, 56Co with a half-life of 77.27 days, and 58Co with a half-life of 70.86 days. All of the remaining radioactive isotopes have half-lives that are shorter than 18 hours, and the majority of these are shorter than 1 second. This element also has 4 meta states, all of which have half-lives shorter than 15 minutes.
The isotopes of cobalt range in atomic weight from 50 u (50Co) to 73 u (73Co). The primary decay mode for isotopes with atomic mass unit values less than that of the most abundant stable isotope, 59Co, is electron capture and the primary mode of decay for those of greater than 59 atomic mass units is beta decay. The primary decay products before 59Co are element 26 (iron) isotopes and the primary products after are element 28 (nickel) isotopes.
# History
Cobalt compounds have been used for centuries to impart a rich blue color to glass, glazes and ceramics. Cobalt has been detected in Egyptian sculpture and Persian jewelry from the third millennium BC, in the ruins of Pompeii (destroyed in 79 AD), and in China dating from the Tang dynasty (618–907 AD) and the Ming dynasty (1368–1644 AD).
Cobalt has been used to color glass since the Bronze Age. The excavation of the Uluburun shipwreck yielded an ingot of blue glass, which was cast during the 14th century BC. Blue glass items from Egypt are colored with copper, iron, or cobalt. The oldest cobalt-colored glass was from the time of the Eighteenth dynasty in Egypt (1550–1292 BC). The location where the cobalt compounds were obtained is unknown.
The word cobalt is derived from the German kobalt, from kobold meaning "goblin", a superstitious term used for the ore of cobalt by miners. The first attempts at smelting these ores to produce metals such as copper or nickel failed, yielding simply powder (cobalt(II) oxide) instead. Also, because the primary ores of cobalt always contain arsenic, smelting the ore oxidized the arsenic content into the highly toxic and volatile arsenic oxide, which also decreased the reputation of the ore for the miners.
Swedish chemist Georg Brandt (1694–1768) is credited with discovering cobalt circa 1735, showing it to be a new previously unknown element different from bismuth and other traditional metals, and calling it a new "semi-metal." He was able to show that compounds of cobalt metal were the source of the blue color in glass, which previously had been attributed to the bismuth found with cobalt. Cobalt became the first metal to be discovered since the pre-historical period, during which all the known metals (iron, copper, silver, gold, zinc, mercury, tin, lead and bismuth) had no recorded discoverers.
During the 19th century, a significant part of the world's production of cobalt blue (a dye made with cobalt compounds and alumina) and smalt (cobalt glass powdered for use for pigment purposes in ceramics and painting) was carried out at the Norwegian Blaafarveværket. The first mines for the production of smalt in the 16th to 18th century were located in Norway, Sweden, Saxony and Hungary. With the discovery of cobalt ore in New Caledonia in 1864 the mining of cobalt in Europe declined. With the discovery of ore deposits in Ontario, Canada in 1904 and the discovery of even larger deposits in the Katanga Province in the Congo in 1914 the mining operations shifted again. With the Shaba conflict starting in 1978, the main source for cobalt, the copper mines of Katanga Province, nearly stopped their production. The impact on the world cobalt economy from this conflict was however smaller than expected. Cobalt being a rare metal and the pigment being highly toxic, the industry had already established effective ways for recycling cobalt materials and in some cases was able to change to cobalt-free alternatives.
In 1938, John Livingood and Glenn T. Seaborg discovered cobalt-60. This isotope was famously used at Columbia University in the 1950s to establish parity violation in radioactive beta decay.
After World War II, the US wanted to be sure it was never short of the ore needed for military cobalt uses (as the Germans had been during that war) and explored for cobalt within the U.S. border. A good supply of the ore needed was found in Idaho near Blackbird canyon in the side of a mountain. The firm Calera Mining Company got production started at the site.
# Occurrence
The stable form of cobalt is created in supernovas via the r-process. It comprises 0.0029% of the Earth's crust and is one of the first transition metal series.
Cobalt occurs in copper and nickel minerals and in combination with sulfur and arsenic in the sulfidic cobaltite (CoAsS), safflorite (CoAs2) and skutterudite (CoAs3) minerals. The mineral cattierite is similar to pyrite and occurs together with vaesite in the copper deposits of the Katanga Province. Upon contact with the atmosphere, weathering occurs and the sulfide minerals oxidize to form pink erythrite ("cobalt glance": Co3(AsO4)2·8H2O) and spherocobaltite (CoCO3).
Cobalt is not found as a native metal. The main ores of cobalt are cobaltite, erythrite, glaucodot and skutterudite, but most cobalt is obtained not by active mining of cobalt ores, but rather by reducing cobalt compounds that occur as by-products of nickel and copper mining activities. ].
# Production
In 2005, the copper deposits in the Katanga Province (former Shaba province) of the Democratic Republic of the Congo were the top producer of cobalt with almost 40% world share, reports the British Geological Survey. The political situation in the Congo influences the price of cobalt significantly.
The Mukondo Mountain project, operated by the Central African Mining and Exploration Company in Katanga, may be the richest cobalt reserve in the world. It is estimated to be able to produce about one third of total global production of cobalt in 2008.
In July 2009 CAMEC announced a long term agreement under which CAMEC would deliver its entire annual production of cobalt in concentrate from Mukondo Mountain to Zhejiang Galico Cobalt & Nickel Materials of China.
Several methods exist for the separation of cobalt from copper and nickel. They depend on the concentration of cobalt and the exact composition of the used ore. One separation step involves froth flotation, in which surfactants bind to different ore components, leading to an enrichment of cobalt ores. Subsequent roasting converts the ores to the cobalt sulfate, whereas the copper and the iron are oxidized to the oxide. The leaching with water extracts the sulfate together with the arsenates. The residues are further leached with sulfuric acid yielding a solution of copper sulfate. Cobalt can also be leached from the slag of the copper smelter.
The products of the above-mentioned processes are transformed into the cobalt oxide (Co3O4). This oxide is reduced to the metal by the aluminothermic reaction or reduction with carbon in a blast furnace.
# Applications
The main application of cobalt is as the free metal, in production of certain high performance alloys.
## Alloys
Cobalt-based superalloys consume most of the produced cobalt. The temperature stability of these alloys makes them suitable for use in turbine blades for gas turbines and jet aircraft engines, though nickel-based single crystal alloys surpass them in this regard. Cobalt-based alloys are also corrosion and wear-resistant. This makes them useful in the medical field, where cobalt is often used (along with titanium) for orthopedic implants that do not wear down over time. The development of the wear-resistant cobalt alloys started in the first decade of the 19th century with the stellite alloys, which are cobalt-chromium alloys with varying tungsten and carbon content. The formation of chromium and tungsten carbides makes them very hard and wear resistant. Special cobalt-chromium-molybdenum alloys like Vitallium are used for prosthetic parts such as hip and knee replacements. Cobalt alloys are also used for dental prosthetics, where they are useful to avoid allergies to nickel. Some high speed steel drill bits also use cobalt to increase heat and wear-resistance. The special alloys of aluminium, nickel, cobalt and iron, known as Alnico, and of samarium and cobalt (samarium-cobalt magnet) are used in permanent magnets. It is also alloyed with 95% platinum for jewelry purposes, yielding an alloy that is suitable for fine detailed casting and is also slightly magnetic.
## Batteries
Lithium cobalt oxide (LiCoO2) is widely used in lithium ion battery cathodes. The material is composed of cobalt oxide layers in which the lithium is intercalated. During discharging the lithium intercalated between the layers is set free as lithium ion. Nickel-cadmium (NiCd) and nickel metal hydride (NiMH) batteries also contain significant amounts of cobalt; the cobalt improves the oxidation capabilities of nickel in the battery.
## Catalysis
Several cobalt compounds are used in chemical reactions as oxidation catalysts. Cobalt acetate is used for the conversion of xylene to terephthalic acid, the precursor to the bulk polymer polyethylene terephthalate. Typical catalysts are the cobalt carboxylates (known as cobalt soaps). They are also used in paints, varnishes, and inks as "drying agents" through the oxidation of drying oils. The same carboxylates are used to improve the adhesion of the steel to rubber in steel-belted radial tires.
Cobalt-based catalysts are also important in reactions involving carbon monoxide. Steam reforming, useful in hydrogen production, uses cobalt oxide-base catalysts. Cobalt is also a catalyst in the Fischer–Tropsch process, used in the hydrogenation of carbon monoxide into liquid fuels. The hydroformylation of alkenes often rely on cobalt octacarbonyl as the catalyst, although such processes have been partially displaced by more efficient iridium- and rhodium-based catalysts, e.g. the Cativa process.
The hydrodesulfurization of petroleum uses a catalyst derived from cobalt and molybdenum. This process helps to rid petroleum of sulfur impurities that interfere with the refining of liquid fuels.
## Pigments and coloring
Before the 19th century, the predominant use of cobalt was as pigment. Since the Middle Ages, it has been involved in the production of smalt, a blue colored glass. Smalt is produced by melting a mixture of the roasted mineral smaltite, quartz and potassium carbonate, yielding a dark blue silicate glass which is ground after the production. Smalt was widely used for the coloration of glass and as pigment for paintings. In 1780, Sven Rinman discovered cobalt green and in 1802 Louis Jacques Thénard discovered cobalt blue. The two varieties of cobalt blue pigment, cobalt blue (cobalt aluminate) and cobalt green (a mixture of cobalt(II) oxide and zinc oxide), were used as pigments for paintings because of their superior stability.
## Radioisotopes
Cobalt-60 (Co-60 or 60Co) is useful as a gamma ray source because it can be produced in predictable quantity and high activity by bombarding cobalt with neutrons. It produces two gamma rays with energies of 1.17 and 1.33 MeV.
Its uses include external beam radiotherapy, sterilization of medical supplies and medical waste, radiation treatment of foods for sterilization (cold pasteurization), industrial radiography (e.g. weld integrity radiographs), density measurements (e.g. concrete density measurements), and tank fill height switches. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation protection. Cobalt from radiotherapy machines has been a serious hazard when not disposed of properly, and one of the worst radiation contamination accidents in North America occurred in 1984, after a discarded radiotherapy unit containing cobalt-60 was mistakenly disassembled in a junkyard in Juarez, Mexico.
Cobalt-60 has a radioactive half-life of 5.27 years. This decrease in activity requires periodic replacement of the sources used in radiotherapy and is one reason why cobalt machines have been largely replaced by linear accelerators in modern radiation therapy.
Cobalt-57 (Co-57 or 57Co) is a cobalt radioisotope most often used in medical tests, as a radiolabel for vitamin BTemplate:Ssub uptake, and for the Schilling test. Cobalt-57 is used as a source in Mössbauer spectroscopy and is one of several possible sources in X-ray fluorescence devices.
Nuclear weapon designs could intentionally incorporate 59Co, some of which would be activated in a nuclear explosion to produce 60Co. The 60Co, dispersed as nuclear fallout, creates what is sometimes called a cobalt bomb.
## Other uses
Other uses of cobalt are in electroplating, owing to its attractive appearance, hardness and resistance to oxidation, and as ground coats for porcelain enamels.
# Biological role
Cobalt is essential to all animals. It is a key constituent of cobalamin, also known as vitamin BTemplate:Ssub, which is the primary biological reservoir of cobalt as an "ultratrace" element. Bacteria in the guts of ruminant animals convert cobalt salts into vitamin BTemplate:Ssub, a compound which can only be produced by bacteria or archaea. The minimum presence of cobalt in soils therefore markedly improves the health of grazing animals, and an uptake of 0.20 mg/kg a day is recommended for them, as they can obtain vitamin BTemplate:Ssub in no other way. In the early 20th century during the development for farming of the North Island Volcanic Plateau of New Zealand, cattle suffered from what was termed "bush sickness". It was discovered that the volcanic soils lacked cobalt salts, which was necessary for cattle. The ailment was cured by adding small amounts of cobalt to fertilizers.
In the 1930s "coast disease" of sheep in the Ninety Mile Desert of the Southeast of South Australia was found to be due to nutrient deficiencies of the trace elements cobalt and copper. The cobalt deficiency was overcome by the development of "cobalt bullets", dense pellets of cobalt oxide mixed with clay, which are orally inserted to lodge in the animal's rumen.
Non-ruminant herbivores produce vitamin BTemplate:Ssub from bacteria in their colons which again make the vitamin from simple cobalt salts. However the vitamin cannot be absorbed from the colon, and thus non-ruminants must ingest feces to obtain the nutrient. Animals that do not follow these methods of getting vitamin BTemplate:Ssub from their own gastrointestinal bacteria or that of other animals, must obtain the vitamin pre-made in other animal products in their diet, and they cannot benefit from ingesting simple cobalt salts.
The cobalamin-based proteins use corrin to hold the cobalt. Coenzyme B12 features a reactive C-Co bond, which participates in its reactions. In humans, B12 exists with two types of alkyl ligand: methyl and adenosyl. MeB12 promotes methyl (-CH3) group transfers. The adenosyl version of B12 catalyzes rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine. Methylmalonyl coenzyme A mutase (MUT) converts MMl-CoA to Su-CoA, an important step in the extraction of energy from proteins and fats.
Although far less common than other metalloproteins (e.g. those of zinc and iron), cobaltoproteins are known aside from B12. These proteins include methionine aminopeptidase 2 an enzyme that occurs in humans and other mammals which does not use the corrin ring of B12, but binds cobalt directly. Another non-corrin cobalt enzyme is nitrile hydratase, an enzyme in bacteria that are able to metabolize nitriles.
# Precautions
Cobalt is an essential element for life in minute amounts. The LD50 value for soluble cobalt salts has been estimated to be between 150 and 500 mg/kg. Thus, for a 100 kg person the LD50 for a single dose would be about 20 grams.
However, chronic cobalt ingestion has caused serious health problems at doses far less than the lethal dose. In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to a pecular form of toxin-induced cardiomyopathy, which came to be known as beer drinker's cardiomyopathy.
After nickel and chromium, cobalt is a major cause of contact dermatitis. | Cobalt
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought by alchemists to be due to the known metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue-pigment producing minerals; they were named because they were poor in known metals and gave poisonous arsenic-containing fumes upon smelting. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the kobold.
Today, some cobalt is produced specifically from various metallic-lustered ores, for example cobaltite (CoAsS), but the main source of the element is as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo and Zambia yields most of the cobalt mined worldwide.
Cobalt is primarily used as the metal, in the preparation of magnetic, wear-resistant and high-strength alloys. Its compounds cobalt silicate and cobalt(II) aluminate (CoAl2O4, cobalt blue) give a distinctive deep blue color to glass, smalt, ceramics, inks, paints and varnishes. Cobalt occurs naturally as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high intensity gamma rays.
Cobalt is the active center of coenzymes called cobalamins, the most common example of which is [[vitamin B12|vitamin BTemplate:Ssub]]. As such it is an essential trace dietary mineral for all animals. Cobalt in inorganic form is also an active nutrient for bacteria, algae and fungi.
# Characteristics
Cobalt is a ferromagnetic metal with a specific gravity of 8.9. Pure cobalt is not found in nature, but compounds of cobalt are common. Small amounts of it are found in most rocks, soil, plants, and animals. The Curie temperature is 1115 °C[1] and the magnetic moment is 1.6–1.7 Bohr magnetons per atom.[2] In nature, it is frequently associated with nickel, and both are characteristic minor components of meteoric iron. Cobalt has a relative permeability two thirds that of iron.[3] Metallic cobalt occurs as two crystallographic structures: hcp and fcc. The ideal transition temperature between the hcp and fcc structures is 450 °C, but in practice, the energy difference is so small that random intergrowth of the two is common.[4][5][6]
Cobalt is a weakly reducing metal that is protected from oxidation by a passivating oxide film. It is attacked by halogens and sulfur. Heating in oxygen produces Co3O4 which loses oxygen at 900 °C to give the monoxide CoO.[7] The metal reacts with Fluorine gas (F2) at 520 K to give CoF3, with chlorine (Cl2), bromine (Br2) and iodine (I2), the corresponding binary halides formed. It has no reaction with hydrogen gas (H2) or nitrogen gas (N2) even when heated, but it does react with boron, carbon, phosphorus, arsenic and sulphur.[8] At ordinary temperatures, it reacts slowly with mineral acids, and very slowly with moist air, but not with dry air.
# Compounds
Common oxidation states of cobalt include +2 and +3, although compounds with oxidation states ranging from −3 to +4 are also known. A common oxidation state for simple compounds is +2. Cobalt(II) salts form the red-pink [Co(H2O)6]2+ complex in aqueous solution. Addition of chloride gives the intensely blue [CoCl4]2−.[9]
## Oxygen and chalcogen compounds
Several oxides of cobalt are known. Green cobalt(II) oxide (CoO) has rocksalt structure. It is readily oxidized with water and oxygen to brown cobalt(III) hydroxide (Co(OH)3). At temperatures of 600–700 °C, CoO oxidizes to the blue cobalt(II,III) oxide (Co3O4), which has a spinel structure.[9] Black cobalt(III) oxide (Co2O3) is also known.[10] Cobalt oxides are antiferromagnetic at low temperature: CoO (Neel temperature 291 K) and Co3O4 (Neel temperature: 40 K), which is analogous to magnetite (Fe3O4), with a mixture of +2 and +3 oxidation states.[11]
The principal chalcogenides of cobalt include the black cobalt(II) sulfides, CoS2, which adopts a pyrite-like structure, and Co2S3. Pentlandite (Co9S8) is metal-rich.[9]
## Halides
Four dihalides of cobalt(II) are known: cobalt(II) fluoride (CoF2, pink), cobalt(II) chloride (CoCl2, blue), cobalt(II) bromide (CoBr2, green), cobalt(II) iodide (CoI2, blue-black). These halides exist in anhydrous and hydrated forms. Whereas the anhydrous dichloride is blue, the hydrate is red.[12]
The reduction potential for the reaction
is +1.92 V, beyond that for chlorine to chloride, +1.36 V. As a consequence cobalt(III) and chloride would result in the cobalt(III) being reduced to cobalt(II). Because the reduction potential for fluorine to fluoride is so high, +2.87 V, cobalt(III) fluoride is one of the few simple stable cobalt(III) compounds. Cobalt(III) fluoride, which is used in some fluorination reactions, reacts vigorously with water.[7]
## Coordination compounds
As for all metals, molecular compounds of cobalt are classified as coordination complexes, that is molecules or ions that contain cobalt linked to several ligands. The principles of electronegativity and hardness–softness of a series of ligands can be used to explain the usual oxidation state of the cobalt. For example Co+3 complexes tend to have ammine ligands. As phosphorus is softer than nitrogen, phosphine ligands tend to feature the softer Co2+ and Co+, an example being tris(triphenylphosphine)cobalt(I) chloride ((P(C6H5)3)3CoCl). The more electronegative (and harder) oxide and fluoride can stabilize Co4+ and Co5+ derivatives, e.g. caesium hexafluorocobaltate (Cs2CoF6) and potassium percobaltate (K3CoO4).[7]
Alfred Werner, a Nobel-prize winning pioneer in coordination chemistry, worked with compounds of empirical formula CoCl3(NH3)6. One of the isomers determined was cobalt(III) hexammine chloride. This coordination complex, a "typical" Werner-type complex, consists of a central cobalt atom coordinated by six ammine ligands orthogonal to each other and three chloride counteranions. Using chelating ethylenediamine ligands in place of ammonia gives tris(ethylenediamine)cobalt(III) chloride ([Co(en)3]Cl3), which was one of the first coordination complexes that was resolved into optical isomers. The complex exists as both either right- or left-handed forms of a "three-bladed propeller". This complex was first isolated by Werner as yellow-gold needle-like crystals.[13][14]
## Organometallic compounds
Cobaltocene is a structural analog to ferrocene, where cobalt substitutes for iron. Cobaltocene is sensitive to oxidation, much more than ferrocene.[15] Cobalt carbonyl (Co2(CO)8) is a catalyst in carbonylation reactions.[16] Vitamin BTemplate:Ssub (see below) is an organometallic compound found in nature and is the only vitamin to contain a metal atom.[17]
# Isotopes
59Co is the only stable cobalt isotope and the only isotope to exist naturally on Earth. 22 radioisotopes have been characterized with the most stable being 60Co with a half-life of 5.2714 years, 57Co with a half-life of 271.79 days, 56Co with a half-life of 77.27 days, and 58Co with a half-life of 70.86 days. All of the remaining radioactive isotopes have half-lives that are shorter than 18 hours, and the majority of these are shorter than 1 second. This element also has 4 meta states, all of which have half-lives shorter than 15 minutes.[18]
The isotopes of cobalt range in atomic weight from 50 u (50Co) to 73 u (73Co). The primary decay mode for isotopes with atomic mass unit values less than that of the most abundant stable isotope, 59Co, is electron capture and the primary mode of decay for those of greater than 59 atomic mass units is beta decay. The primary decay products before 59Co are element 26 (iron) isotopes and the primary products after are element 28 (nickel) isotopes.[18]
# History
Cobalt compounds have been used for centuries to impart a rich blue color to glass, glazes and ceramics. Cobalt has been detected in Egyptian sculpture and Persian jewelry from the third millennium BC, in the ruins of Pompeii (destroyed in 79 AD), and in China dating from the Tang dynasty (618–907 AD) and the Ming dynasty (1368–1644 AD).[19]
Cobalt has been used to color glass since the Bronze Age. The excavation of the Uluburun shipwreck yielded an ingot of blue glass, which was cast during the 14th century BC.[20][21] Blue glass items from Egypt are colored with copper, iron, or cobalt. The oldest cobalt-colored glass was from the time of the Eighteenth dynasty in Egypt (1550–1292 BC). The location where the cobalt compounds were obtained is unknown.[22][23]
The word cobalt is derived from the German kobalt, from kobold meaning "goblin", a superstitious term used for the ore of cobalt by miners. The first attempts at smelting these ores to produce metals such as copper or nickel failed, yielding simply powder (cobalt(II) oxide) instead. Also, because the primary ores of cobalt always contain arsenic, smelting the ore oxidized the arsenic content into the highly toxic and volatile arsenic oxide, which also decreased the reputation of the ore for the miners.[24]
Swedish chemist Georg Brandt (1694–1768) is credited with discovering cobalt circa 1735, showing it to be a new previously unknown element different from bismuth and other traditional metals, and calling it a new "semi-metal."[25][26] He was able to show that compounds of cobalt metal were the source of the blue color in glass, which previously had been attributed to the bismuth found with cobalt. Cobalt became the first metal to be discovered since the pre-historical period, during which all the known metals (iron, copper, silver, gold, zinc, mercury, tin, lead and bismuth) had no recorded discoverers.[27]
During the 19th century, a significant part of the world's production of cobalt blue (a dye made with cobalt compounds and alumina) and smalt (cobalt glass powdered for use for pigment purposes in ceramics and painting) was carried out at the Norwegian Blaafarveværket.[28][29] The first mines for the production of smalt in the 16th to 18th century were located in Norway, Sweden, Saxony and Hungary. With the discovery of cobalt ore in New Caledonia in 1864 the mining of cobalt in Europe declined. With the discovery of ore deposits in Ontario, Canada in 1904 and the discovery of even larger deposits in the Katanga Province in the Congo in 1914 the mining operations shifted again.[24] With the Shaba conflict starting in 1978, the main source for cobalt, the copper mines of Katanga Province, nearly stopped their production.[30][31] The impact on the world cobalt economy from this conflict was however smaller than expected. Cobalt being a rare metal and the pigment being highly toxic, the industry had already established effective ways for recycling cobalt materials and in some cases was able to change to cobalt-free alternatives.[30][31]
In 1938, John Livingood and Glenn T. Seaborg discovered cobalt-60.[32] This isotope was famously used at Columbia University in the 1950s to establish parity violation in radioactive beta decay.[33][34]
After World War II, the US wanted to be sure it was never short of the ore needed for military cobalt uses (as the Germans had been during that war) and explored for cobalt within the U.S. border. A good supply of the ore needed was found in Idaho near Blackbird canyon in the side of a mountain. The firm Calera Mining Company got production started at the site.[35]
# Occurrence
The stable form of cobalt is created in supernovas via the r-process.[36] It comprises 0.0029% of the Earth's crust and is one of the first transition metal series.
Cobalt occurs in copper and nickel minerals and in combination with sulfur and arsenic in the sulfidic cobaltite (CoAsS), safflorite (CoAs2) and skutterudite (CoAs3) minerals.[7] The mineral cattierite is similar to pyrite and occurs together with vaesite in the copper deposits of the Katanga Province.[37] Upon contact with the atmosphere, weathering occurs and the sulfide minerals oxidize to form pink erythrite ("cobalt glance": Co3(AsO4)2·8H2O) and spherocobaltite (CoCO3).[38][39]
Cobalt is not found as a native metal. The main ores of cobalt are cobaltite, erythrite, glaucodot and skutterudite, but most cobalt is obtained not by active mining of cobalt ores, but rather by reducing cobalt compounds that occur as by-products of nickel and copper mining activities. ].[40][41]
# Production
In 2005, the copper deposits in the Katanga Province (former Shaba province) of the Democratic Republic of the Congo were the top producer of cobalt with almost 40% world share, reports the British Geological Survey.[42] The political situation in the Congo influences the price of cobalt significantly.[43]
The Mukondo Mountain project, operated by the Central African Mining and Exploration Company in Katanga, may be the richest cobalt reserve in the world. It is estimated to be able to produce about one third of total global production of cobalt in 2008.[44]
In July 2009 CAMEC announced a long term agreement under which CAMEC would deliver its entire annual production of cobalt in concentrate from Mukondo Mountain to Zhejiang Galico Cobalt & Nickel Materials of China.[45]
Several methods exist for the separation of cobalt from copper and nickel. They depend on the concentration of cobalt and the exact composition of the used ore. One separation step involves froth flotation, in which surfactants bind to different ore components, leading to an enrichment of cobalt ores. Subsequent roasting converts the ores to the cobalt sulfate, whereas the copper and the iron are oxidized to the oxide. The leaching with water extracts the sulfate together with the arsenates. The residues are further leached with sulfuric acid yielding a solution of copper sulfate. Cobalt can also be leached from the slag of the copper smelter.[46]
The products of the above-mentioned processes are transformed into the cobalt oxide (Co3O4). This oxide is reduced to the metal by the aluminothermic reaction or reduction with carbon in a blast furnace.[7]
# Applications
The main application of cobalt is as the free metal, in production of certain high performance alloys.[40][41]
## Alloys
Cobalt-based superalloys consume most of the produced cobalt.[40][41] The temperature stability of these alloys makes them suitable for use in turbine blades for gas turbines and jet aircraft engines, though nickel-based single crystal alloys surpass them in this regard.[47] Cobalt-based alloys are also corrosion and wear-resistant. This makes them useful in the medical field, where cobalt is often used (along with titanium) for orthopedic implants that do not wear down over time. The development of the wear-resistant cobalt alloys started in the first decade of the 19th century with the stellite alloys, which are cobalt-chromium alloys with varying tungsten and carbon content. The formation of chromium and tungsten carbides makes them very hard and wear resistant.[48] Special cobalt-chromium-molybdenum alloys like Vitallium are used for prosthetic parts such as hip and knee replacements.[49] Cobalt alloys are also used for dental prosthetics, where they are useful to avoid allergies to nickel.[50] Some high speed steel drill bits also use cobalt to increase heat and wear-resistance. The special alloys of aluminium, nickel, cobalt and iron, known as Alnico, and of samarium and cobalt (samarium-cobalt magnet) are used in permanent magnets.[51] It is also alloyed with 95% platinum for jewelry purposes, yielding an alloy that is suitable for fine detailed casting and is also slightly magnetic.[52]
## Batteries
Lithium cobalt oxide (LiCoO2) is widely used in lithium ion battery cathodes. The material is composed of cobalt oxide layers in which the lithium is intercalated. During discharging the lithium intercalated between the layers is set free as lithium ion.[53] Nickel-cadmium[54] (NiCd) and nickel metal hydride[55] (NiMH) batteries also contain significant amounts of cobalt; the cobalt improves the oxidation capabilities of nickel in the battery.[54]
## Catalysis
Several cobalt compounds are used in chemical reactions as oxidation catalysts. Cobalt acetate is used for the conversion of xylene to terephthalic acid, the precursor to the bulk polymer polyethylene terephthalate. Typical catalysts are the cobalt carboxylates (known as cobalt soaps). They are also used in paints, varnishes, and inks as "drying agents" through the oxidation of drying oils.[53] The same carboxylates are used to improve the adhesion of the steel to rubber in steel-belted radial tires.
Cobalt-based catalysts are also important in reactions involving carbon monoxide. Steam reforming, useful in hydrogen production, uses cobalt oxide-base catalysts. Cobalt is also a catalyst in the Fischer–Tropsch process, used in the hydrogenation of carbon monoxide into liquid fuels.[56] The hydroformylation of alkenes often rely on cobalt octacarbonyl as the catalyst,[57] although such processes have been partially displaced by more efficient iridium- and rhodium-based catalysts, e.g. the Cativa process.
The hydrodesulfurization of petroleum uses a catalyst derived from cobalt and molybdenum. This process helps to rid petroleum of sulfur impurities that interfere with the refining of liquid fuels.[53]
## Pigments and coloring
Before the 19th century, the predominant use of cobalt was as pigment. Since the Middle Ages, it has been involved in the production of smalt, a blue colored glass. Smalt is produced by melting a mixture of the roasted mineral smaltite, quartz and potassium carbonate, yielding a dark blue silicate glass which is ground after the production.[58] Smalt was widely used for the coloration of glass and as pigment for paintings.[59] In 1780, Sven Rinman discovered cobalt green and in 1802 Louis Jacques Thénard discovered cobalt blue.[60] The two varieties of cobalt blue pigment, cobalt blue (cobalt aluminate) and cobalt green (a mixture of cobalt(II) oxide and zinc oxide), were used as pigments for paintings because of their superior stability.[61][62]
## Radioisotopes
Cobalt-60 (Co-60 or 60Co) is useful as a gamma ray source because it can be produced in predictable quantity and high activity by bombarding cobalt with neutrons. It produces two gamma rays with energies of 1.17 and 1.33 MeV.[18][63]
Its uses include external beam radiotherapy, sterilization of medical supplies and medical waste, radiation treatment of foods for sterilization (cold pasteurization),[64] industrial radiography (e.g. weld integrity radiographs), density measurements (e.g. concrete density measurements), and tank fill height switches. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation protection. Cobalt from radiotherapy machines has been a serious hazard when not disposed of properly, and one of the worst radiation contamination accidents in North America occurred in 1984, after a discarded radiotherapy unit containing cobalt-60 was mistakenly disassembled in a junkyard in Juarez, Mexico.[65][66]
Cobalt-60 has a radioactive half-life of 5.27 years. This decrease in activity requires periodic replacement of the sources used in radiotherapy and is one reason why cobalt machines have been largely replaced by linear accelerators in modern radiation therapy.[67]
Cobalt-57 (Co-57 or 57Co) is a cobalt radioisotope most often used in medical tests, as a radiolabel for vitamin BTemplate:Ssub uptake, and for the Schilling test. Cobalt-57 is used as a source in Mössbauer spectroscopy and is one of several possible sources in X-ray fluorescence devices.[68][69]
Nuclear weapon designs could intentionally incorporate 59Co, some of which would be activated in a nuclear explosion to produce 60Co. The 60Co, dispersed as nuclear fallout, creates what is sometimes called a cobalt bomb.[70]
## Other uses
Other uses of cobalt are in electroplating, owing to its attractive appearance, hardness and resistance to oxidation,[71] and as ground coats for porcelain enamels.[72]
# Biological role
Cobalt is essential to all animals. It is a key constituent of cobalamin, also known as vitamin BTemplate:Ssub, which is the primary biological reservoir of cobalt as an "ultratrace" element.[73] Bacteria in the guts of ruminant animals convert cobalt salts into vitamin BTemplate:Ssub, a compound which can only be produced by bacteria or archaea. The minimum presence of cobalt in soils therefore markedly improves the health of grazing animals, and an uptake of 0.20 mg/kg a day is recommended for them, as they can obtain vitamin BTemplate:Ssub in no other way.[74] In the early 20th century during the development for farming of the North Island Volcanic Plateau of New Zealand, cattle suffered from what was termed "bush sickness". It was discovered that the volcanic soils lacked cobalt salts, which was necessary for cattle.[75] The ailment was cured by adding small amounts of cobalt to fertilizers.
In the 1930s "coast disease" of sheep in the Ninety Mile Desert of the Southeast of South Australia was found to be due to nutrient deficiencies of the trace elements cobalt and copper. The cobalt deficiency was overcome by the development of "cobalt bullets", dense pellets of cobalt oxide mixed with clay, which are orally inserted to lodge in the animal's rumen.[76]
Non-ruminant herbivores produce vitamin BTemplate:Ssub from bacteria in their colons which again make the vitamin from simple cobalt salts. However the vitamin cannot be absorbed from the colon, and thus non-ruminants must ingest feces to obtain the nutrient. Animals that do not follow these methods of getting vitamin BTemplate:Ssub from their own gastrointestinal bacteria or that of other animals, must obtain the vitamin pre-made in other animal products in their diet, and they cannot benefit from ingesting simple cobalt salts.
The cobalamin-based proteins use corrin to hold the cobalt. Coenzyme B12 features a reactive C-Co bond, which participates in its reactions.[77] In humans, B12 exists with two types of alkyl ligand: methyl and adenosyl. MeB12 promotes methyl (-CH3) group transfers. The adenosyl version of B12 catalyzes rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine. Methylmalonyl coenzyme A mutase (MUT) converts MMl-CoA to Su-CoA, an important step in the extraction of energy from proteins and fats.[78]
Although far less common than other metalloproteins (e.g. those of zinc and iron), cobaltoproteins are known aside from B12. These proteins include methionine aminopeptidase 2 an enzyme that occurs in humans and other mammals which does not use the corrin ring of B12, but binds cobalt directly. Another non-corrin cobalt enzyme is nitrile hydratase, an enzyme in bacteria that are able to metabolize nitriles.[79]
# Precautions
Cobalt is an essential element for life in minute amounts. The LD50 value for soluble cobalt salts has been estimated to be between 150 and 500 mg/kg. Thus, for a 100 kg person the LD50 for a single dose would be about 20 grams.[80]
However, chronic cobalt ingestion has caused serious health problems at doses far less than the lethal dose. In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to a pecular form of toxin-induced cardiomyopathy, which came to be known as beer drinker's cardiomyopathy.[81]
After nickel and chromium, cobalt is a major cause of contact dermatitis.[82] | https://www.wikidoc.org/index.php/Cobalt | |
cfa1f62145aceaaa43809e51b8f027f00e683468 | wikidoc | Coccus | Coccus
# Overview
Cocci (singular - coccus, from the Latin coccinus (scarlet) and derived from the Greek kokkos (berry) ) are any microorganism (usually bacteria) whose overall shape is spherical or nearly spherical.
Aggregations of coccoid bacteria often occur and these forms have specific names as well; listed here are the basic forms as well as representative bacterial genera:
- pairs, or diplococci (Neisseria)
- groups of four or eight known as tetrads or sarcina (Micrococci)
- bead-like chains, or streptococci (Streptococcus)
- grapelike clusters, or staphylococci (Staphylococcus)
Important human pathogens caused by coccoid bacteria include staphylococci infections, some types of food poisoning,
some urinary tract infections, toxic shock syndrome, gonorrhea, as well as some forms of meningitis, throat infections, pneumonias, and sinusitis. | Coccus
# Overview
Cocci (singular - coccus, from the Latin coccinus (scarlet) and derived from the Greek kokkos (berry) ) are any microorganism (usually bacteria) whose overall shape is spherical or nearly spherical.[1]
Aggregations of coccoid bacteria often occur and these forms have specific names as well[2]; listed here are the basic forms as well as representative bacterial genera:
- pairs, or diplococci (Neisseria)
- groups of four or eight known as tetrads or sarcina (Micrococci)
- bead-like chains, or streptococci (Streptococcus)
- grapelike clusters, or staphylococci (Staphylococcus)
Important human pathogens caused by coccoid bacteria include staphylococci infections, some types of food poisoning,
some urinary tract infections, toxic shock syndrome, gonorrhea, as well as some forms of meningitis, throat infections, pneumonias, and sinusitis.[3] | https://www.wikidoc.org/index.php/Cocci | |
9b27f2f6dc735a140bb2edaf91a8b49344fee5f2 | wikidoc | Coccyx | Coccyx
# Overview
The coccyx (pronounced kok-siks) (Latin: os coccygis), commonly referred to as the tailbone, is the final segment of the human vertebral column, of four fused vertebrae (the coccygeal vertebrae) below the sacrum. It is attached to the sacrum in a fibrocartilaginous joint, which permits limited movement between them. The term coccyx comes originally from the Greek language and means "cuckoo," referring to the shape of a cuckoo's beak.
# Function
The coccyx provides an attachment for nine muscles, such as the gluteus maximus, and those necessary for defecation. It also acts as something of a shock absorber when a person sits down, although forceful impact can cause damage and subsequent bodily pains. In tailed species the coccygeal vertebrae support the tail and accommodate its nerves.
# Structure
The coccyx is usually formed of four rudimentary vertebrae; the number may be as high as five or as low as three. It articulates superiorly with the sacrum. In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone. All the segments are destitute of pedicles, laminae, and spinous processes. The first is the largest; it resembles the lowest sacral vertebra, and often exists as a separate piece; the last three diminish in size from above downward. Most anatomy books wrongly state that the coccyx is normally fused in adults. In fact it has been shown that the coccyx may consist of up to 5 separate bony segments, the most common configuration being two or three segments. Only about 5% of the population have a coccyx in one piece, separate from the sacrum, as described in anatomy books. This error in anatomy teaching can lead doctors to diagnose a 'fractured coccyx' when they see a coccyx in several segments on x-ray.
## Surfaces
The anterior surface is slightly concave, and marked with three transverse grooves which indicate the junctions of the different segments. It gives attachment to the anterior sacrococcygeal ligament and the Levatores ani, and supports part of the rectum.
The posterior surface is convex, marked by transverse grooves similar to those on the anterior surface, and presents on either side a linear row of tubercles, the rudimentary articular processes of the coccygeal vertebrae. Of these, the superior pair are large, and are called the coccygeal cornua; they project upward, and articulate with the cornua of the sacrum, and on either side complete the foramen for the transmission of the posterior division of the fifth sacral nerve.
## Borders
The lateral borders are thin, and exhibit a series of small eminences, which represent the transverse processes of the coccygeal vertebrae. Of these, the first is the largest; it is flattened from before backward, and often ascends to join the lower part of the thin lateral edge of the sacrum, thus completing the foramen for the transmission of the anterior division of the fifth sacral nerve; the others diminish in size from above downward, and are often wanting. The borders of the coccyx are narrow, and give attachment on either side to the sacrotuberous and sacrospinous ligaments, to the Coccygeus in front of the ligaments, and to the gluteus maximus behind them.
## Apex
The apex is rounded, and has attached to it the tendon of the Sphincter ani externus. It may be bifid.
## Sacrococcygeal and intercoccygeal joints
The joints are variable and may be: (1) synovial joints; (2) thin discs of fibrocartilage; (3) intermediate between these two; (4) ossified.
# Pathology
Injuring the coccyx can give rise to a condition called coccydynia.
# Additional images
- Vertebral column.
- Vertebral column.
- Left Levator ani from within.
- Median sagittal section of male pelvis.
- Median sagittal section of female pelvis. | Coccyx
Editor-In-Chief: Patrick Foye, MD, Associate Professor, and Director, Coccyx Pain Service, New Jersey Medical School [1]
# Overview
The coccyx (pronounced kok-siks) (Latin: os coccygis), commonly referred to as the tailbone, is the final segment of the human vertebral column, of four fused vertebrae (the coccygeal vertebrae) below the sacrum. It is attached to the sacrum in a fibrocartilaginous joint, which permits limited movement between them. The term coccyx comes originally from the Greek language and means "cuckoo," referring to the shape of a cuckoo's beak[1].
# Function
The coccyx provides an attachment for nine muscles, such as the gluteus maximus, and those necessary for defecation. It also acts as something of a shock absorber when a person sits down, although forceful impact can cause damage and subsequent bodily pains. In tailed species the coccygeal vertebrae support the tail and accommodate its nerves.
# Structure
The coccyx is usually formed of four rudimentary vertebrae; the number may be as high as five or as low as three. It articulates superiorly with the sacrum. In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone. All the segments are destitute of pedicles, laminae, and spinous processes. The first is the largest; it resembles the lowest sacral vertebra, and often exists as a separate piece; the last three diminish in size from above downward. Most anatomy books wrongly state that the coccyx is normally fused in adults. In fact it has been shown[2] [3] that the coccyx may consist of up to 5 separate bony segments, the most common configuration being two or three segments. Only about 5% of the population have a coccyx in one piece, separate from the sacrum, as described in anatomy books. This error in anatomy teaching can lead doctors to diagnose a 'fractured coccyx' when they see a coccyx in several segments on x-ray.[citation needed]
## Surfaces
The anterior surface is slightly concave, and marked with three transverse grooves which indicate the junctions of the different segments. It gives attachment to the anterior sacrococcygeal ligament and the Levatores ani, and supports part of the rectum.
The posterior surface is convex, marked by transverse grooves similar to those on the anterior surface, and presents on either side a linear row of tubercles, the rudimentary articular processes of the coccygeal vertebrae. Of these, the superior pair are large, and are called the coccygeal cornua; they project upward, and articulate with the cornua of the sacrum, and on either side complete the foramen for the transmission of the posterior division of the fifth sacral nerve.
## Borders
The lateral borders are thin, and exhibit a series of small eminences, which represent the transverse processes of the coccygeal vertebrae. Of these, the first is the largest; it is flattened from before backward, and often ascends to join the lower part of the thin lateral edge of the sacrum, thus completing the foramen for the transmission of the anterior division of the fifth sacral nerve; the others diminish in size from above downward, and are often wanting. The borders of the coccyx are narrow, and give attachment on either side to the sacrotuberous and sacrospinous ligaments, to the Coccygeus in front of the ligaments, and to the gluteus maximus behind them.
## Apex
The apex is rounded, and has attached to it the tendon of the Sphincter ani externus. It may be bifid.
## Sacrococcygeal and intercoccygeal joints
The joints are variable and may be: (1) synovial joints; (2) thin discs of fibrocartilage; (3) intermediate between these two; (4) ossified.[4]
[5]
# Pathology
Injuring the coccyx can give rise to a condition called coccydynia. [6] [7]
# Additional images
- Vertebral column.
- Vertebral column.
- Left Levator ani from within.
- Median sagittal section of male pelvis.
- Median sagittal section of female pelvis. | https://www.wikidoc.org/index.php/Coccygeal | |
42f2d77f936232290db2f1fec96696f93d3bd2e4 | wikidoc | Coffea | Coffea
Coffea (coffee) is a genus of ten species of flowering plants in the family Rubiaceae. They are shrubs or small trees, native to subtropical Africa and southern Asia. Seeds of this plant are the source of a stimulating beverage called coffee. The seeds are called "beans" in the trade. Coffee beans are widely cultivated in tropical countries in plantations for both local consumption and export to temperate countries. Coffee ranks as one of the world's major commodity crops and is the major export product of some countries.
# Botany
When grown in the tropics coffee is a vigorous bush or small tree easily grown to a height of 3–3.5 m (10–12 feet). It is capable of withstanding severe pruning. It cannot be grown where there is a winter frost. Bushes grow best at high elevations. To produce a maximum yield of coffee berries (800-1400 kg per hectare), the plants need substantial amounts of water and fertilizer. Calcium carbonate and other lime minerals are sometimes used to reduce acidity in the soil, which can occur due to run off of minerals from the soil in mountainous areas. The caffeine content in coffee "beans" is a natural defense, the toxic substance repelling many creatures that would otherwise eat the seeds, as with nicotine in tobacco leaves.
There are several species of Coffee that may be grown for the beans, but Coffea arabica is considered to have the best quality. The other species (especially Coffea canephora (var. robusta)) are grown on land unsuitable for Coffea arabica. The tree produces red or purple fruits (drupes, or "coffee berries"), which contain two seeds (the "coffee beans", although not true beans). In about 5-10% of any crop of coffee cherries, the cherry will contain only a single bean, rather than the two usually found. This is called a 'peaberry' and contains a distinctly different flavor profile to the normal crop, with a higher concentration of the flavors, especially acidity, present due to the smaller sized bean. As such, it is usually removed from the yield and either sold separately (such as in New Guinea Peaberry), or discarded.
The coffee tree will grow fruits after 3–5 years, for about 50–60 years (although up to 100 years is possible). The blossom of the coffee tree is similar to jasmine in color and smell. The fruit takes about nine months to ripen. Worldwide, an estimate of 15 billion coffee trees are growing on 100,000 km² of land.
Coffee is used as a food plant by the larvae of some Lepidoptera species including Dalcera abrasa, Turnip Moth and some members of the genus Endoclita including E. damor and E. malabaricus.
# Processing
After picking, the coffee beans are pulped (usually using a mechanical pulper) to remove the bulk of the soft flesh, and then the beans are fermented (by one of several means, most often wet fermentation in water for 10 to 36 hours), then washed (to remove the last of the sticky mucilage not removed by fermentation) and dried (usually in the sun). This process is time-consuming, expensive and, for most growers, labour-intensive. Coffee beans at this stage are known as milled beans.
Once the raw ('green') coffee beans arrive in their destination country, they are roasted; this darkens their color and alters the internal chemistry of the beans and therefore their flavor and aroma. Blending can occur before or after roasting and is often performed to ensure a consistent flavor. Once the beans are roasted, they become much more perishable.
## The economics of growing coffee
It is very questionable whether small growers can generate a high return on capital growing coffee if they have less than 1.2 ha (3 acres or 12,000 m²) and if they are based in the United States. The retail price of the beans varies between about 1 USD/pound for ripe berries to 9 USD/pound for Kona milled beans, and there are many costs including fertiliser, irrigation, labour (e.g. picking and pruning) and land value. Integrated operations that capture much or all of the available revenue (by controlling the whole process from growing to retail) may generate higher returns.
It is estimated that 10 million people are working on plantations in the source lands of coffee. A single worker can harvest 50–100 kg of fruits per day, which results in 10–20 kg of raw coffee. Crops from Brazil (30%) and Colombia (10%) comprise 40% of the worldwide coffee production. As of 1998, the world's coffee production equals about 100 million sacks of coffee.
Many farmers receive a low price for their coffee because of a global market slump. This has led to coffee being available as a 'fair trade' labelled item in many countries.
## Shade Grown Coffee
In its natural environment, coffea grows under the shade. Most coffee is produced on full-sun plantations, some of which were prepared through deforestation. Shade grown coffee naturally mulches its environment, lives twice as long as sun grown varieties, and depletes less of the soil's resources. Shade grown coffee is also believed by some to be of higher quality than sun grown varieties, as the cherries produced by the coffea plants under the shade are not as large as commercial varieties. Some believe that this smaller cherry concentrates the flavors of the cherry into the seed (bean) itself.
Shade grown coffee is also associated with environmentally friendly ecosystems that provide a wider variety and number of migratory birds than those of sun grown coffea farms. | Coffea
Coffea (coffee) is a genus of ten species of flowering plants in the family Rubiaceae. They are shrubs or small trees, native to subtropical Africa and southern Asia. Seeds of this plant are the source of a stimulating beverage called coffee. The seeds are called "beans" in the trade. Coffee beans are widely cultivated in tropical countries in plantations for both local consumption and export to temperate countries. Coffee ranks as one of the world's major commodity crops and is the major export product of some countries.
# Botany
When grown in the tropics coffee is a vigorous bush or small tree easily grown to a height of 3–3.5 m (10–12 feet). It is capable of withstanding severe pruning. It cannot be grown where there is a winter frost. Bushes grow best at high elevations. To produce a maximum yield of coffee berries (800-1400 kg per hectare), the plants need substantial amounts of water and fertilizer. Calcium carbonate and other lime minerals are sometimes used to reduce acidity in the soil, which can occur due to run off of minerals from the soil in mountainous areas.[1] The caffeine content in coffee "beans" is a natural defense, the toxic substance repelling many creatures that would otherwise eat the seeds, as with nicotine in tobacco leaves.
There are several species of Coffee that may be grown for the beans, but Coffea arabica is considered to have the best quality. The other species (especially Coffea canephora (var. robusta)) are grown on land unsuitable for Coffea arabica. The tree produces red or purple fruits (drupes, or "coffee berries"), which contain two seeds (the "coffee beans", although not true beans). In about 5-10% of any crop of coffee cherries, the cherry will contain only a single bean, rather than the two usually found. This is called a 'peaberry' and contains a distinctly different flavor profile to the normal crop, with a higher concentration of the flavors, especially acidity, present due to the smaller sized bean. As such, it is usually removed from the yield and either sold separately (such as in New Guinea Peaberry), or discarded.
The coffee tree will grow fruits after 3–5 years, for about 50–60 years (although up to 100 years is possible). The blossom of the coffee tree is similar to jasmine in color and smell. The fruit takes about nine months to ripen. Worldwide, an estimate of 15 billion coffee trees are growing on 100,000 km² of land.
Coffee is used as a food plant by the larvae of some Lepidoptera species including Dalcera abrasa, Turnip Moth and some members of the genus Endoclita including E. damor and E. malabaricus.
# Processing
Template:See details
After picking, the coffee beans are pulped (usually using a mechanical pulper) to remove the bulk of the soft flesh, and then the beans are fermented (by one of several means, most often wet fermentation in water for 10 to 36 hours), then washed (to remove the last of the sticky mucilage not removed by fermentation) and dried (usually in the sun). This process is time-consuming, expensive and, for most growers, labour-intensive. Coffee beans at this stage are known as milled beans.
Once the raw ('green') coffee beans arrive in their destination country, they are roasted; this darkens their color and alters the internal chemistry of the beans and therefore their flavor and aroma. Blending can occur before or after roasting and is often performed to ensure a consistent flavor. Once the beans are roasted, they become much more perishable.
## The economics of growing coffee
It is very questionable whether small growers can generate a high return on capital growing coffee if they have less than 1.2 ha (3 acres or 12,000 m²) and if they are based in the United States. The retail price of the beans varies between about 1 USD/pound for ripe berries to 9 USD/pound for Kona milled beans, and there are many costs including fertiliser, irrigation, labour (e.g. picking and pruning) and land value. Integrated operations that capture much or all of the available revenue (by controlling the whole process from growing to retail) may generate higher returns.
It is estimated that 10 million people are working on plantations in the source lands of coffee. A single worker can harvest 50–100 kg of fruits per day, which results in 10–20 kg of raw coffee. Crops from Brazil (30%) and Colombia (10%) comprise 40% of the worldwide coffee production. As of 1998, the world's coffee production equals about 100 million sacks of coffee.
Many farmers receive a low price for their coffee because of a global market slump. This has led to coffee being available as a 'fair trade' labelled item in many countries.
## Shade Grown Coffee
In its natural environment, coffea grows under the shade.[1] Most coffee is produced on full-sun plantations, some of which were prepared through deforestation.[2] Shade grown coffee naturally mulches its environment, lives twice as long as sun grown varieties, and depletes less of the soil's resources.[3] Shade grown coffee is also believed by some to be of higher quality than sun grown varieties, as the cherries produced by the coffea plants under the shade are not as large as commercial varieties.[4] Some believe that this smaller cherry concentrates the flavors of the cherry into the seed (bean) itself.[5]
Shade grown coffee is also associated with environmentally friendly ecosystems that provide a wider variety and number of migratory birds than those of sun grown coffea farms.[6] | https://www.wikidoc.org/index.php/Coffea | |
d17997e3e95a4ad491e15351dc0205ed4cd2c3a0 | wikidoc | Coffee | Coffee
Coffee is a widely consumed stimulant beverage prepared from roasted seeds, commonly called beans, of the coffee plant. Coffee was first consumed in the 9th century, when it was discovered in the highlands of Ethiopia. From there, it spread to Egypt and Yemen, and by the 15th century had reached Persia, Turkey, and northern Africa. From the Muslim world, coffee spread to Italy, then to the rest of Europe and the Americas. Today, coffee is one of the most popular beverages worldwide.
Coffee have berries, which contain the coffee bean, are produced by several species of small evergreen bush of the genus Coffea. The two most commonly grown species are Coffea canephora (also known as Coffea robusta) and Coffea arabica. These are cultivated in Latin America, southeast Asia, and Africa. Once ripe, coffee berries are picked, processed, and dried. The seeds are then roasted, undergoing several physical and chemical changes. They are roasted to various degrees, depending on the desired flavor. They are then ground and brewed to create coffee. Coffee can be found in a country named tutscua.
Coffee has played an important role in many societies throughout modern history. In Africa and Yemen, it was used in religious ceremonies. As a result, the Ethiopian Church banned its consumption until the reign of Emperor Menelik II of Ethiopia. It was banned in Ottoman Turkey in the 17th century for political reasons, and was associated with rebellious political activities in Europe. Coffee is an important export commodity: in 2004, coffee was the top agricultural export for 12 countries; and in 2005, it was the world's seventh largest legal agricultural export by value. Some controversy is associated with coffee cultivation and its impact on the environment. Many studies have examined the relationship between coffee consumption and certain medical conditions; whether the effects of coffee are positive or negative is still disputed.
# Etymology
The English word coffee first came to be used in the early- to mid-1600s, but early forms of the word date to the last decade of the 1500s. It comes from the Italian caffè. This, in turn, was borrowed from the Ottoman Turkish kahveh, and the Arabic qahwa (قهوة) collectively. The origin of the Arabic term is uncertain; it is either derived from the name of the Kaffa (Ethiopic ከፋ) region in western Ethiopia, where coffee was cultivated, or by a truncation of qahwat al-būnn, meaning "wine of the bean" in Arabic. In Eritrea, "būnn" (also meaning "wine of the bean" in Tigrinya) is used. The Amharic and Afan Oromo name for coffee is bunna.
# History
Coffee use can be traced at least to as early as the 9th century, when it appeared in the highlands of Ethiopia. According to legend, Ethiopian shepherds were the first to observe the influence of the caffeine in coffee beans when the goats appeared to "dance" and to have an increased level of energy after consuming wild coffee berries. The legend names the shepherd "Kaldi." From Ethiopia, coffee spread to Egypt and Yemen, and by the 15th century, it had reached the rest of the Middle East, Persia, Turkey, and northern Africa.
In 1583, Leonhard Rauwolf, a German physician, gave this description of coffee after returning from a ten year trip to the Near East:
From the Muslim world, coffee spread to Italy. The thriving trade between Venice and North Africa, Egypt, and the Middle East brought many goods, including coffee, to the Venetian port. From Venice, it was introduced to the rest of Europe. Coffee became more widely accepted after it was deemed a Christian beverage by Pope Clement VIII in 1600, despite appeals to ban the "Muslim drink". The first European coffee house opened in Italy in 1645. The Dutch were the first to import coffee on a large scale, and they were among the first to defy the Arab prohibition on the exportation of plants or unroasted seeds when Pieter van den Broeck smuggled seedlings from Aden into Europe in 1616. The Dutch later grew the crop in Java and Ceylon. Through the efforts of the British East India Company, coffee became popular in England as well. It was introduced in France in 1657, and in Austria and Poland after the 1683 Battle of Vienna, when coffee was captured from supplies of the defeated Turks.
When coffee reached North America during the colonial period, it was initially not as successful as it had been in Europe. During the Revolutionary War, however, the demand for coffee increased so much that dealers had to hoard their scarce supplies and raise prices dramatically; this was partly due to the reduced availability of tea from British merchants. After the War of 1812, during which Britain temporarily cut off access to tea imports, the Americans' taste for coffee grew, and high demand during the American Civil War together with advances in brewing technology secured the position of coffee as an everyday commodity in the United States.
# Biology
The Coffea plant is native to subtropical Africa and southern Asia.
It belongs to a genus of 10 species of flowering plants of the family Rubiaceae. It is an evergreen shrub or small tree that may grow 5 meters (16 ft) tall when unpruned. The leaves are dark green and glossy, usually 10–15 centimeters (3.9–5.9 in) long and 6.0 centimeters (2.4 in) wide. It produces clusters of fragrant, white flowers that bloom simultaneously. The fruit berry is oval, about 1.5 centimeters (0.6 in) long, and green when immature, but ripens to yellow, then crimson, becoming black on drying. Each berry usually contains two seeds, but from 5 to 10 percent of the berries have only one; these are called peaberries. Berries ripen in seven to nine months.
# Cultivation
Coffee is usually propagated by seed. The traditional method of planting coffee is to put 20 seeds in each hole at the beginning of the rainy season; half are eliminated naturally. Coffee is often intercropped with food crops, such as corn, beans, or rice, during the first few years of cultivation.
The two main cultivated species of the coffee plant are Coffea canephora and Coffea arabica. Arabica coffee (from C. arabica) is considered more suitable for drinking than robusta coffee (from C. canephora); robusta tends to be bitter and have less flavor than arabica. For this reason, about three-fourths of coffee cultivated worldwide is C. arabica. However, C. canephora is less susceptible to disease than C. arabica and can be cultivated in environments where C. arabica will not thrive. Robusta coffee also contains about 40–50 percent more caffeine than arabica. For this reason, it is used as an inexpensive substitute for arabica in many commercial coffee blends. Good quality robustas are used in some espresso blends to provide a better foam head and to lower the ingredient cost. Other cultivated species include Coffea liberica and Coffea esliaca, believed to be indigenous to Liberia and southern Sudan, respectively.
Most arabica coffee beans originate from either Latin America, eastern Africa, Arabia, or Asia. Robusta coffee beans are grown in western and central Africa, throughout southeast Asia, and to some extent in Brazil. Beans from different countries or regions usually have distinctive characteristics such as flavor, aroma, body, and acidity. These taste characteristics are dependent not only on the coffee's growing region, but also on genetic subspecies (varietals) and processing. Varietals are generally known by the region in which they are grown, such as Colombian, Java, or Kona.
## Ecological effects
Originally, coffee farming was done in the shade of trees, which provided habitat for many animals and insects. Today, farmers use sun cultivation, in which coffee is grown in rows under full sun with little or no forest canopy. This causes berries to ripen more rapidly and bushes to produce higher yields but requires the clearing of trees and increased use of fertilizer and pesticides. Opponents of sun cultivation say environmental problems such as deforestation, pesticide pollution, habitat destruction, and soil and water degradation are the side effects of these practices. The American Birding Association has led a campaign for "shade-grown" and organic coffees, which it says are sustainably harvested. While certain types of shaded coffee cultivation systems show greater biodiversity than full-sun systems, they still compare poorly to native forest in terms of habitat value, and some researchers are concerned that the push for "shade grown" coffee may actually be encouraging deforestation in ecologically sensitive regions.
# Processing
## Roasting
Coffee berries and their seeds undergo multi-step processing before they become the roasted coffee with which most consumers are familiar. First, coffee berries are picked, generally by hand. Then, the flesh of the berry is removed, usually by machine, and the seeds—usually called beans—are fermented to remove the slimy layer of mucilage still present on the bean. When the fermentation is finished, the beans are washed with large quantities of fresh water to remove the fermentation residue, generating massive amounts of highly polluted coffee wastewater. Finally the seeds are dried and sorted and labeled as green coffee beans.
The next step in the process is the roasting of the green coffee. Coffee is usually sold in a roasted state, and all coffee is roasted before it is consumed. It can be sold roasted by the supplier, or it can be home roasted. The roasting process influences the taste of the beverage by changing the coffee bean both physically and chemically. The bean decreases in weight as moisture is lost but increases in volume, causing it to become less dense. The density of the bean also influences the strength of the coffee and requirements for packaging. The actual roasting begins when the temperature inside the bean reaches 200 °C (392 °F), though different varieties of beans differ in moisture and density and therefore roast at different rates. During roasting, caramelization occurs as intense heat breaks down starches in the bean, changing them to simple sugars that begin to brown, changing the color of the bean. Sucrose is rapidly lost during the roasting process and may disappear entirely in darker roasts. During roasting, aromatic oils, acids, and caffeine weaken, changing the flavor; at 205 °C (400 °F), other oils start to develop. One of these oils is caffeol, created at about 200 °C (392 °F), which is largely responsible for coffee's aroma and flavor.
Depending on the color of the roasted beans, they will be labeled as light, cinnamon, medium, high, city, full city, French, or Italian roast. Darker roasts are generally smoother, because they have less fiber content and a more sugary flavor. Lighter roasts have more caffeine, resulting in a slight bitterness, and a stronger flavor from aromatic oils and acids destroyed by longer roasting times. A small amount of chaff is produced during roasting from the skin left on the bean after processing. Chaff is usually removed from the beans by air movement, though a small amount is added to dark roast coffees to soak up oils on the beans. Decaffeination may also be part of the processing that coffee seeds undergo. Seeds are decaffeinated when they are still green. Many methods can remove caffeine from coffee, but all involve either soaking beans in hot water or steaming them, then using a solvent to dissolve caffeine-containing oils. Decaffeination is often done by processing companies, and the extracted caffeine is usually sold to the pharmaceutical industry.
## Storage
Once roasted, coffee beans must be stored properly to preserve the fresh taste of the bean. Ideal conditions are air-tight and cool. Air, moisture, heat and light are the environmental factors in order of importance to preserving flavor in coffee beans.
Typical commercial coffee containers in which coffee is purchased are generally not ideal for long-term storage. Some newer packages contain one-way valves which allow for the release of carbon dioxide (a byproduct of the roasting process) while preventing air from entering the bag.
## Preparation
Coffee beans must be ground and brewed in order to create a beverage. Grinding the roasted coffee beans is done at a roastery, in a grocery store, or in the home. They are most commonly ground at a roastery then packaged and sold to the consumer, though "whole bean" coffee can be ground at home. Coffee beans may be ground in several ways. A burr mill uses revolving elements to crush or tear the bean, an electric grinder chops the beans with blades moving at high speeds, and a mortar and pestle grinds the beans to a powder. The type of grind is often named after the brewing method for which it is generally used. Turkish grind is the finest grind, while coffee percolator or French press are the coarsest grind. The most common grinds are between the extremes; a medium grind is used in most common home coffee brewing machines.
Coffee may be brewed by several methods: boiled, steeped, or pressured. Brewing coffee by boiling was the earliest method, and Turkish coffee is an example of this method. It is prepared by powdering the beans with a mortar and pestle, then adding the powder to water and bringing it to a boil in a pot called a cezve or, in Greek, a briki. This produces a strong coffee with a layer of foam on the surface.
Machines such as percolators or automatic coffeemakers brew coffee by gravity. In an automatic coffeemaker, hot water drips onto coffee grounds held in a coffee filter made of paper or perforated metal, allowing the water to seep through the ground coffee while absorbing its oils and essences. Gravity causes the liquid to pass into a carafe or pot while the used coffee grounds are retained in the filter. In a percolator, boiling water is forced into a chamber above a filter by pressure created by boiling. The water then passes downwards through the grounds due to gravity, repeating the process until shut off by an internal timer.
Coffee may also be brewed by steeping in a device such as a French press (also known as a cafetière). Ground coffee and hot water are combined in a coffee press and left to brew for a few minutes. A plunger is then depressed to separate the coffee grounds, which remain at the bottom of the container. Because the coffee grounds are in direct contact with the water, all the coffee oils remain in the beverage, making it stronger and leaving more sediment than in coffee made by an automatic coffee machine.
The espresso method forces hot, but not boiling, pressurized water through ground coffee. As a result of brewing under high pressure (ideally between 9-10 atm) the espresso beverage is more concentrated (as much as 10 to 15 times the amount of coffee to water as gravity brewing methods can produce) and has a more complex physical and chemical constitution. A well prepared espresso has a reddish-brown foam called crema that floats on the surface. The drink "Americano" is popularly thought to have been named after American soldiers in WW II who found the European way of drinking espresso too strong. Baristas would cut the espresso with hot water for them.
## Presentation
Once brewed, coffee may be presented in a variety of ways. Drip brewed, percolated, or French-pressed/cafetière coffee may be served with no additives (colloquially known as black) or with either sugar, milk or cream, or both. When served cold, it is called iced coffee.
Espresso-based coffee has a wide variety of possible presentations. In its most basic form, it is served alone as a "shot" or in the more watered down style café américano—a shot or two of espresso with hot water. The Americano should be served with the espresso shots on top of the hot water to preserve the crema. Milk can be added in various forms to espresso: steamed milk makes a caffè latte, equal parts espresso and milk froth make a cappuccino, and a dollop of hot, foamed milk on top creates a caffè macchiato.
A number of products are sold for the convenience of consumers who do not want to prepare their own coffee. Instant coffee is dried into soluble powder or freeze dried into granules that can be quickly dissolved in hot water. Canned coffee has been popular in Asian countries for many years, particularly in Japan and South Korea. Vending machines typically sell varieties of flavored canned coffee, much like brewed or percolated coffee, available both hot and cold. Japanese convenience stores and groceries also have a wide availability of bottled coffee drinks, which are typically lightly sweetened and pre-blended with milk. Bottled coffee drinks are also consumed in the United States. Liquid coffee concentrates are sometimes used in large institutional situations where coffee needs to be produced for thousands of people at the same time. It is described as having a flavor about as good as low-grade robusta coffee and costs about 10 cents a cup to produce. The machines used can process up to 500 cups an hour, or 1,000 if the water is preheated.
# Social aspects
Coffee was initially used for spiritual reasons. At least 1,000 years ago, traders brought coffee across the Red Sea into Arabia (modern day Yemen), where Muslim monks began cultivating the shrub in their gardens. At first, the Arabians made wine from the pulp of the fermented coffee berries. This beverage was known as qishr (kisher in modern usage) and was used during religious ceremonies.
Coffee became the substitute beverage in place of wine in spiritual practices where wine was forbidden. Coffee drinking was briefly prohibited to Muslims as haraam in the early years of the 16th century, but this was quickly overturned. Use in religious rites among the Sufi branch of Islam led to coffee's being put on trial in Mecca, accused of being a heretic substance, and its production and consumption was briefly repressed. It was later prohibited in Ottoman Turkey under an edict by the Sultan Murad IV. Coffee, regarded as a Muslim drink, was prohibited to Ethiopian Orthodox Christians until as late as 1889; it is now considered a national drink of Ethiopia for people of all faiths. Its early association in Europe with rebellious political activities led to its banning in England, among other places.
A contemporary example of coffee prohibition can be found in The Church of Jesus Christ of Latter-day Saints, a religion with over 13 million followers worldwide, which calls for coffee abstinence. The organization claims that it is both physically and spiritually unhealthy to consume coffee. This comes from the Mormon doctrine of health, given in 1833 by Mormon founder Joseph Smith, in a revelation called the Word of Wisdom. It does not identify coffee by name, but includes the statement that "hot drinks are not for the belly", which has been interpreted to forbid both coffee and tea.
# Health and pharmacology
Scientific studies have examined the relationship between coffee consumption and an array of medical conditions. Most studies are contradictory as to whether coffee has any specific health benefits, and results are similarly conflicting regarding negative effects of coffee consumption.
Coffee appears to reduce the risk of Alzheimer's disease, Parkinson's disease, heart disease, diabetes mellitus type 2, cirrhosis of the liver, and gout. Some health effects are due to the caffeine content of coffee, as the benefits are only observed in those who drink caffeinated coffee, while others appear to be due to other components. For example, the antioxidants in coffee prevent free radicals from causing cell damage.
Coffee's negative health effects are mostly due to its caffeine content. Research suggests that drinking caffeinated coffee can cause a temporary increase in the stiffening of arterial walls. Excess coffee consumption may lead to a magnesium deficiency or hypomagnesaemia, and may be a risk factor for coronary heart disease. Some studies suggest that it may have a mixed effect on short-term memory, by improving it when the information to be recalled is related to the current train of thought, but making it more difficult to recall unrelated information. Nevertheless, the mainstream view of medical experts is that drinking three 8-ounce (236 ml) cups of coffee per day (considered average or moderate consumption) does not have significant health risks for adults.
An American scientist Yaser Dorri has recently suggested that coffee beans can restore the appetite after cooking and refresh olfactory receptors. He believes the intense odorants in coffee release the sensory receptors in the nose. This scientist sugguest that people can regain their appetite by smelling coffee beans. He has suggested this method to be also used for animals in research institutes.
## Caffeine content
Depending on the type of coffee and method of preparation, the caffeine content of a single serving can vary greatly. On average, a single cup of coffee of about 207 milliliters (7 fluid ounces) or a single shot of espresso of about 30 mL (1oz) can be expected to contain the following amounts of caffeine:
- Drip coffee: 115–175 mg
- Espresso: 30 mg
- Colombian Espresso: 40 mg
- Brewed/Pressed: 80–135 mg
- Instant: 65–100 mg
- Decaf, brewed: 3–4 mg
- Decaf, instant: 2–3 mg
# Economics
Coffee ingestion on average is about a third of that of tap water in North America and Europe. Worldwide, 6.7 million metric tons of coffee were produced annually in 1998–2000, and the forecast is a rise to 7 million metric tons annually by 2010.
Brazil remains the largest coffee exporting nation, but in recent years Vietnam has become a major producer of robusta beans. Colombia is the third exporter and the largest producer of washed arabica coffee. Robusta coffees, traded in London at much lower prices than New York's arabica, are preferred by large industrial clients, such as multinational roasters and instant coffee producers, because of the lower cost. Four single roaster companies buy more than 50 percent of all of the annual production: Kraft, Nestlé, Procter & Gamble, and Sara Lee. The preference of the "Big Four" coffee companies for cheap robusta is believed by many to have been a major contributing factor to the crash in coffee prices, and the demand for high-quality arabica beans is only slowly recovering.
Many experts believe the giant influx of cheap green coffee after the collapse of the International Coffee Agreement of 1975–1989 led to the prolonged price crisis from 1989 to 2004. In 1997 the price of coffee in New York broke US$3.00/lb, but by late 2001 it had fallen to US$0.43/lb. In 2007, wholesale coffee was about US$1/lb (e.g. 69 cents in London in March to 134 cents in New York in October), with robusta being about 70% of the price of arabica. Retail prices varied from an average of $3 in Poland to $3.50 in the US to $17 in the UK.
The concept of fair trade labeling, which guarantees coffee growers a negotiated pre-harvest price, began with the Max Havelaar Foundation's labelling program in the Netherlands. In 2004, 24,222 metric tons out of 7,050,000 produced worldwide were fair trade; in 2005, 33,991 metric tons out of 6,685,000 were fair trade, an increase from 0.34 percent to 0.51 percent. A number of studies have shown that fair trade coffee has a positive impact on the communities that grow it.
A study in 2002 found that fair trade strengthened producer organizations, improved returns to small producers, and positively affected their quality of life. A 2003 study concluded that fair trade has "greatly improved the well-being of small-scale coffee farmers and their families" by providing access to credit and external development funding and greater access to training, giving them the ability to improve the quality of their coffee. The families of fair trade producers were also more stable than those who were not involved in fair trade, and their children had better access to education. A 2005 study of Bolivian coffee producers concluded that Fairtrade certification has had a positive impact on local coffee prices, economically benefiting all coffee producers, Fairtrade certified or not.
The production and consumption of "Fair Trade Coffee" has grown in recent years as some local and national coffee chains have started to offer fair trade alternatives. | Coffee
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3]
Template:Infobox Beverage
Coffee is a widely consumed stimulant beverage prepared from roasted seeds, commonly called beans, of the coffee plant. Coffee was first consumed in the 9th century, when it was discovered in the highlands of Ethiopia.[1] From there, it spread to Egypt and Yemen, and by the 15th century had reached Persia, Turkey, and northern Africa. From the Muslim world, coffee spread to Italy, then to the rest of Europe and the Americas.[2] Today, coffee is one of the most popular beverages worldwide.[3]
Coffee have berries, which contain the coffee bean, are produced by several species of small evergreen bush of the genus Coffea. The two most commonly grown species are Coffea canephora (also known as Coffea robusta) and Coffea arabica. These are cultivated in Latin America, southeast Asia, and Africa. Once ripe, coffee berries are picked, processed, and dried. The seeds are then roasted, undergoing several physical and chemical changes. They are roasted to various degrees, depending on the desired flavor. They are then ground and brewed to create coffee. Coffee can be found in a country named tutscua.
Coffee has played an important role in many societies throughout modern history. In Africa and Yemen, it was used in religious ceremonies. As a result, the Ethiopian Church banned its consumption until the reign of Emperor Menelik II of Ethiopia.[4] It was banned in Ottoman Turkey in the 17th century for political reasons, and was associated with rebellious political activities in Europe. Coffee is an important export commodity: in 2004, coffee was the top agricultural export for 12 countries;[5] and in 2005, it was the world's seventh largest legal agricultural export by value.[6] Some controversy is associated with coffee cultivation and its impact on the environment. Many studies have examined the relationship between coffee consumption and certain medical conditions; whether the effects of coffee are positive or negative is still disputed.[7]
# Etymology
The English word coffee first came to be used in the early- to mid-1600s, but early forms of the word date to the last decade of the 1500s.[8] It comes from the Italian caffè. This, in turn, was borrowed from the Ottoman Turkish kahveh, and the Arabic qahwa (قهوة) collectively.[9] The origin of the Arabic term is uncertain; it is either derived from the name of the Kaffa (Ethiopic ከፋ) region in western Ethiopia, where coffee was cultivated, or by a truncation of qahwat al-būnn, meaning "wine of the bean" in Arabic. In Eritrea, "būnn" (also meaning "wine of the bean" in Tigrinya) is used.[10] The Amharic and Afan Oromo name for coffee is bunna.
# History
Coffee use can be traced at least to as early as the 9th century, when it appeared in the highlands of Ethiopia.[1] According to legend, Ethiopian shepherds were the first to observe the influence of the caffeine in coffee beans when the goats appeared to "dance" and to have an increased level of energy after consuming wild coffee berries.[11] The legend names the shepherd "Kaldi." From Ethiopia, coffee spread to Egypt and Yemen,[12] and by the 15th century, it had reached the rest of the Middle East, Persia, Turkey, and northern Africa.
In 1583, Leonhard Rauwolf, a German physician, gave this description of coffee after returning from a ten year trip to the Near East:[13]
From the Muslim world, coffee spread to Italy. The thriving trade between Venice and North Africa, Egypt, and the Middle East brought many goods, including coffee, to the Venetian port. From Venice, it was introduced to the rest of Europe. Coffee became more widely accepted after it was deemed a Christian beverage by Pope Clement VIII in 1600, despite appeals to ban the "Muslim drink". The first European coffee house opened in Italy in 1645.[2] The Dutch were the first to import coffee on a large scale, and they were among the first to defy the Arab prohibition on the exportation of plants or unroasted seeds when Pieter van den Broeck smuggled seedlings from Aden into Europe in 1616.[14] The Dutch later grew the crop in Java and Ceylon.[15] Through the efforts of the British East India Company, coffee became popular in England as well. It was introduced in France in 1657, and in Austria and Poland after the 1683 Battle of Vienna, when coffee was captured from supplies of the defeated Turks.[16]
When coffee reached North America during the colonial period, it was initially not as successful as it had been in Europe. During the Revolutionary War, however, the demand for coffee increased so much that dealers had to hoard their scarce supplies and raise prices dramatically; this was partly due to the reduced availability of tea from British merchants.[17] After the War of 1812, during which Britain temporarily cut off access to tea imports, the Americans' taste for coffee grew, and high demand during the American Civil War together with advances in brewing technology secured the position of coffee as an everyday commodity in the United States.[18]
# Biology
The Coffea plant is native to subtropical Africa and southern Asia.[19]
It belongs to a genus of 10 species of flowering plants of the family Rubiaceae. It is an evergreen shrub or small tree that may grow 5 meters (16 ft) tall when unpruned. The leaves are dark green and glossy, usually 10–15 centimeters (3.9–5.9 in) long and 6.0 centimeters (2.4 in) wide. It produces clusters of fragrant, white flowers that bloom simultaneously. The fruit berry is oval, about 1.5 centimeters (0.6 in) long,[20] and green when immature, but ripens to yellow, then crimson, becoming black on drying. Each berry usually contains two seeds, but from 5 to 10 percent of the berries[21] have only one; these are called peaberries.[22] Berries ripen in seven to nine months.
# Cultivation
Coffee is usually propagated by seed. The traditional method of planting coffee is to put 20 seeds in each hole at the beginning of the rainy season; half are eliminated naturally. Coffee is often intercropped with food crops, such as corn, beans, or rice, during the first few years of cultivation.[20]
The two main cultivated species of the coffee plant are Coffea canephora and Coffea arabica. Arabica coffee (from C. arabica) is considered more suitable for drinking than robusta coffee (from C. canephora); robusta tends to be bitter and have less flavor than arabica. For this reason, about three-fourths of coffee cultivated worldwide is C. arabica.[19] However, C. canephora is less susceptible to disease than C. arabica and can be cultivated in environments where C. arabica will not thrive. Robusta coffee also contains about 40–50 percent more caffeine than arabica.[1] For this reason, it is used as an inexpensive substitute for arabica in many commercial coffee blends. Good quality robustas are used in some espresso blends to provide a better foam head and to lower the ingredient cost.[23] Other cultivated species include Coffea liberica and Coffea esliaca, believed to be indigenous to Liberia and southern Sudan, respectively.[1]
Most arabica coffee beans originate from either Latin America, eastern Africa, Arabia, or Asia. Robusta coffee beans are grown in western and central Africa, throughout southeast Asia, and to some extent in Brazil.[19] Beans from different countries or regions usually have distinctive characteristics such as flavor, aroma, body, and acidity.[24] These taste characteristics are dependent not only on the coffee's growing region, but also on genetic subspecies (varietals) and processing.[25] Varietals are generally known by the region in which they are grown, such as Colombian, Java, or Kona.
## Ecological effects
Originally, coffee farming was done in the shade of trees, which provided habitat for many animals and insects.[26] Today, farmers use sun cultivation, in which coffee is grown in rows under full sun with little or no forest canopy. This causes berries to ripen more rapidly and bushes to produce higher yields but requires the clearing of trees and increased use of fertilizer and pesticides.[27] Opponents of sun cultivation say environmental problems such as deforestation, pesticide pollution, habitat destruction, and soil and water degradation are the side effects of these practices.[26] The American Birding Association has led a campaign for "shade-grown" and organic coffees, which it says are sustainably harvested.[28] While certain types of shaded coffee cultivation systems show greater biodiversity than full-sun systems, they still compare poorly to native forest in terms of habitat value,[29] and some researchers are concerned that the push for "shade grown" coffee may actually be encouraging deforestation in ecologically sensitive regions.[30]
# Processing
## Roasting
Coffee berries and their seeds undergo multi-step processing before they become the roasted coffee with which most consumers are familiar. First, coffee berries are picked, generally by hand. Then, the flesh of the berry is removed, usually by machine, and the seeds—usually called beans—are fermented to remove the slimy layer of mucilage still present on the bean. When the fermentation is finished, the beans are washed with large quantities of fresh water to remove the fermentation residue, generating massive amounts of highly polluted coffee wastewater. Finally the seeds are dried and sorted and labeled as green coffee beans.[31]
The next step in the process is the roasting of the green coffee. Coffee is usually sold in a roasted state, and all coffee is roasted before it is consumed. It can be sold roasted by the supplier, or it can be home roasted.[32] The roasting process influences the taste of the beverage by changing the coffee bean both physically and chemically. The bean decreases in weight as moisture is lost but increases in volume, causing it to become less dense. The density of the bean also influences the strength of the coffee and requirements for packaging. The actual roasting begins when the temperature inside the bean reaches 200 °C (392 °F), though different varieties of beans differ in moisture and density and therefore roast at different rates.[33] During roasting, caramelization occurs as intense heat breaks down starches in the bean, changing them to simple sugars that begin to brown, changing the color of the bean.[34] Sucrose is rapidly lost during the roasting process and may disappear entirely in darker roasts. During roasting, aromatic oils, acids, and caffeine weaken, changing the flavor; at 205 °C (400 °F), other oils start to develop.[33] One of these oils is caffeol, created at about 200 °C (392 °F), which is largely responsible for coffee's aroma and flavor.[15]
Depending on the color of the roasted beans, they will be labeled as light, cinnamon, medium, high, city, full city, French, or Italian roast.[35] Darker roasts are generally smoother, because they have less fiber content and a more sugary flavor. Lighter roasts have more caffeine, resulting in a slight bitterness, and a stronger flavor from aromatic oils and acids destroyed by longer roasting times.[36] A small amount of chaff is produced during roasting from the skin left on the bean after processing.[37] Chaff is usually removed from the beans by air movement, though a small amount is added to dark roast coffees to soak up oils on the beans.[33] Decaffeination may also be part of the processing that coffee seeds undergo. Seeds are decaffeinated when they are still green. Many methods can remove caffeine from coffee, but all involve either soaking beans in hot water or steaming them, then using a solvent to dissolve caffeine-containing oils.[15] Decaffeination is often done by processing companies, and the extracted caffeine is usually sold to the pharmaceutical industry.[15]
## Storage
Once roasted, coffee beans must be stored properly to preserve the fresh taste of the bean. Ideal conditions are air-tight and cool. Air, moisture, heat and light are the environmental factors in order of importance to preserving flavor in coffee beans.
Typical commercial coffee containers in which coffee is purchased are generally not ideal for long-term storage. Some newer packages contain one-way valves which allow for the release of carbon dioxide (a byproduct of the roasting process) while preventing air from entering the bag.
## Preparation
Coffee beans must be ground and brewed in order to create a beverage. Grinding the roasted coffee beans is done at a roastery, in a grocery store, or in the home. They are most commonly ground at a roastery then packaged and sold to the consumer, though "whole bean" coffee can be ground at home. Coffee beans may be ground in several ways. A burr mill uses revolving elements to crush or tear the bean, an electric grinder chops the beans with blades moving at high speeds, and a mortar and pestle grinds the beans to a powder.[38] The type of grind is often named after the brewing method for which it is generally used. Turkish grind is the finest grind, while coffee percolator or French press are the coarsest grind. The most common grinds are between the extremes; a medium grind is used in most common home coffee brewing machines.[39]
Coffee may be brewed by several methods: boiled, steeped, or pressured. Brewing coffee by boiling was the earliest method, and Turkish coffee is an example of this method.[40] It is prepared by powdering the beans with a mortar and pestle, then adding the powder to water and bringing it to a boil in a pot called a cezve or, in Greek, a briki. This produces a strong coffee with a layer of foam on the surface.[40]
Machines such as percolators or automatic coffeemakers brew coffee by gravity. In an automatic coffeemaker, hot water drips onto coffee grounds held in a coffee filter made of paper or perforated metal, allowing the water to seep through the ground coffee while absorbing its oils and essences. Gravity causes the liquid to pass into a carafe or pot while the used coffee grounds are retained in the filter.[41] In a percolator, boiling water is forced into a chamber above a filter by pressure created by boiling. The water then passes downwards through the grounds due to gravity, repeating the process until shut off by an internal timer.[41]
Coffee may also be brewed by steeping in a device such as a French press (also known as a cafetière). Ground coffee and hot water are combined in a coffee press and left to brew for a few minutes. A plunger is then depressed to separate the coffee grounds, which remain at the bottom of the container. Because the coffee grounds are in direct contact with the water, all the coffee oils remain in the beverage, making it stronger and leaving more sediment than in coffee made by an automatic coffee machine.[42]
The espresso method forces hot, but not boiling, pressurized water through ground coffee. As a result of brewing under high pressure (ideally between 9-10 atm) the espresso beverage is more concentrated (as much as 10 to 15 times the amount of coffee to water as gravity brewing methods can produce) and has a more complex physical and chemical constitution. A well prepared espresso has a reddish-brown foam called crema that floats on the surface.[39] The drink "Americano" is popularly thought to have been named after American soldiers in WW II who found the European way of drinking espresso too strong. Baristas would cut the espresso with hot water for them.
## Presentation
Once brewed, coffee may be presented in a variety of ways. Drip brewed, percolated, or French-pressed/cafetière coffee may be served with no additives (colloquially known as black) or with either sugar, milk or cream, or both. When served cold, it is called iced coffee.
Espresso-based coffee has a wide variety of possible presentations. In its most basic form, it is served alone as a "shot" or in the more watered down style café américano—a shot or two of espresso with hot water.[43] The Americano should be served with the espresso shots on top of the hot water to preserve the crema. Milk can be added in various forms to espresso: steamed milk makes a caffè latte,[44] equal parts espresso and milk froth make a cappuccino,[43] and a dollop of hot, foamed milk on top creates a caffè macchiato.[45]
A number of products are sold for the convenience of consumers who do not want to prepare their own coffee. Instant coffee is dried into soluble powder or freeze dried into granules that can be quickly dissolved in hot water.[46] Canned coffee has been popular in Asian countries for many years, particularly in Japan and South Korea. Vending machines typically sell varieties of flavored canned coffee, much like brewed or percolated coffee, available both hot and cold. Japanese convenience stores and groceries also have a wide availability of bottled coffee drinks, which are typically lightly sweetened and pre-blended with milk. Bottled coffee drinks are also consumed in the United States.[47] Liquid coffee concentrates are sometimes used in large institutional situations where coffee needs to be produced for thousands of people at the same time. It is described as having a flavor about as good as low-grade robusta coffee and costs about 10 cents a cup to produce. The machines used can process up to 500 cups an hour, or 1,000 if the water is preheated.[48]
# Social aspects
Coffee was initially used for spiritual reasons. At least 1,000 years ago, traders brought coffee across the Red Sea into Arabia (modern day Yemen), where Muslim monks began cultivating the shrub in their gardens. At first, the Arabians made wine from the pulp of the fermented coffee berries. This beverage was known as qishr (kisher in modern usage) and was used during religious ceremonies.[citation needed]
Coffee became the substitute beverage in place of wine in spiritual practices where wine was forbidden.[11] Coffee drinking was briefly prohibited to Muslims as haraam in the early years of the 16th century, but this was quickly overturned. Use in religious rites among the Sufi branch of Islam led to coffee's being put on trial in Mecca, accused of being a heretic substance, and its production and consumption was briefly repressed. It was later prohibited in Ottoman Turkey under an edict by the Sultan Murad IV.[49] Coffee, regarded as a Muslim drink, was prohibited to Ethiopian Orthodox Christians until as late as 1889; it is now considered a national drink of Ethiopia for people of all faiths. Its early association in Europe with rebellious political activities led to its banning in England, among other places.[50]
A contemporary example of coffee prohibition can be found in The Church of Jesus Christ of Latter-day Saints, a religion with over 13 million followers worldwide, which calls for coffee abstinence. The organization claims that it is both physically and spiritually unhealthy to consume coffee.[51] This comes from the Mormon doctrine of health, given in 1833 by Mormon founder Joseph Smith, in a revelation called the Word of Wisdom. It does not identify coffee by name, but includes the statement that "hot drinks are not for the belly", which has been interpreted to forbid both coffee and tea.[51]
# Health and pharmacology
Scientific studies have examined the relationship between coffee consumption and an array of medical conditions. Most studies are contradictory as to whether coffee has any specific health benefits, and results are similarly conflicting regarding negative effects of coffee consumption.[7]
Coffee appears to reduce the risk of Alzheimer's disease, Parkinson's disease, heart disease, diabetes mellitus type 2, cirrhosis of the liver,[52] and gout. Some health effects are due to the caffeine content of coffee, as the benefits are only observed in those who drink caffeinated coffee, while others appear to be due to other components.[53] For example, the antioxidants in coffee prevent free radicals from causing cell damage.[54]
Coffee's negative health effects are mostly due to its caffeine content. Research suggests that drinking caffeinated coffee can cause a temporary increase in the stiffening of arterial walls.[55] Excess coffee consumption may lead to a magnesium deficiency or hypomagnesaemia[56], and may be a risk factor for coronary heart disease. Some studies suggest that it may have a mixed effect on short-term memory, by improving it when the information to be recalled is related to the current train of thought, but making it more difficult to recall unrelated information.[57] Nevertheless, the mainstream view of medical experts is that drinking three 8-ounce (236 ml) cups of coffee per day (considered average or moderate consumption) does not have significant health risks for adults.[58]
An American scientist Yaser Dorri has recently suggested that coffee beans can restore the appetite after cooking and refresh olfactory receptors. He believes the intense odorants in coffee release the sensory receptors in the nose. This scientist sugguest that people can regain their appetite by smelling coffee beans. He has suggested this method to be also used for animals in research institutes. [59]
## Caffeine content
Depending on the type of coffee and method of preparation, the caffeine content of a single serving can vary greatly. On average, a single cup of coffee of about 207 milliliters (7 fluid ounces) or a single shot of espresso of about 30 mL (1oz) can be expected to contain the following amounts of caffeine:[60][61][62]
- Drip coffee: 115–175 mg
- Espresso: 30 mg
- Colombian Espresso: 40 mg
- Brewed/Pressed: 80–135 mg
- Instant: 65–100 mg
- Decaf, brewed: 3–4 mg
- Decaf, instant: 2–3 mg
# Economics
Coffee ingestion on average is about a third of that of tap water in North America and Europe.[3] Worldwide, 6.7 million metric tons of coffee were produced annually in 1998–2000, and the forecast is a rise to 7 million metric tons annually by 2010.[63]
Brazil remains the largest coffee exporting nation, but in recent years Vietnam has become a major producer of robusta beans.[64] Colombia is the third exporter and the largest producer of washed arabica coffee. Robusta coffees, traded in London at much lower prices than New York's arabica, are preferred by large industrial clients, such as multinational roasters and instant coffee producers, because of the lower cost. Four single roaster companies buy more than 50 percent of all of the annual production: Kraft, Nestlé, Procter & Gamble, and Sara Lee.[65] The preference of the "Big Four" coffee companies for cheap robusta is believed by many to have been a major contributing factor to the crash in coffee prices,[66] and the demand for high-quality arabica beans is only slowly recovering.
Many experts believe the giant influx of cheap green coffee after the collapse of the International Coffee Agreement of 1975–1989 led to the prolonged price crisis from 1989 to 2004.[67] In 1997 the price of coffee in New York broke US$3.00/lb, but by late 2001 it had fallen to US$0.43/lb.[68] In 2007, wholesale coffee was about US$1/lb (e.g. 69 cents in London in March to 134 cents in New York in October), with robusta being about 70% of the price of arabica. Retail prices varied from an average of $3 in Poland to $3.50 in the US to $17 in the UK.[69]
The concept of fair trade labeling, which guarantees coffee growers a negotiated pre-harvest price, began with the Max Havelaar Foundation's labelling program in the Netherlands. In 2004, 24,222 metric tons out of 7,050,000 produced worldwide were fair trade; in 2005, 33,991 metric tons out of 6,685,000 were fair trade, an increase from 0.34 percent to 0.51 percent.[70][71] A number of studies have shown that fair trade coffee has a positive impact on the communities that grow it.
A study in 2002 found that fair trade strengthened producer organizations, improved returns to small producers, and positively affected their quality of life.[72] A 2003 study concluded that fair trade has "greatly improved the well-being of small-scale coffee farmers and their families"[73] by providing access to credit and external development funding[74] and greater access to training, giving them the ability to improve the quality of their coffee.[75] The families of fair trade producers were also more stable than those who were not involved in fair trade, and their children had better access to education.[76] A 2005 study of Bolivian coffee producers concluded that Fairtrade certification has had a positive impact on local coffee prices, economically benefiting all coffee producers, Fairtrade certified or not.[77]
The production and consumption of "Fair Trade Coffee" has grown in recent years as some local and national coffee chains have started to offer fair trade alternatives. [78] | https://www.wikidoc.org/index.php/Coffee |
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