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b56a053efa3c45ef672860974dc26fd1084d8821 | wikidoc | Heparin | Heparin
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
# Overview
Heparin is an unfractionated heparin that is FDA approved for the treatment of atrial fibrillation and disseminated intravascular coagulation; It is used as a prophylaxis for pulmonary embolism, thrombosis,venous catheter occlusion and
venous thromboembolism.. Common adverse reactions include thrombocytopenia and increased liver aminotransferase level.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
# Indications
- Heparin Sodium Injection is indicated for:
- Anticoagulant therapy in prophylaxis and treatment of venous thrombosis and its extension;
- (In a low-dose regimen) for prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdomino-thoracic surgery or who for other reasons are at risk of developing thromboembolic disease;
- Prophylaxis and treatment of pulmonary embolism;
- Atrial fibrillation with embolization;
- Diagnosis and treatment of acute and chronic consumption coagulopathies (disseminated intravascular coagulation);
- Prevention of clotting in arterial and heart surgery;
- Prophylaxis and treatment of peripheral arterial embolism;
- As an anticoagulant in blood transfusions, extracorporeal circulation, and dialysis procedures and in blood samples for laboratory purposes.
# Dosage
- Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Slight discoloration does not alter potency.
- When heparin is added to an infusion solution for continuous intravenous administration, the container should be inverted at least six times to ensure adequate mixing and prevent pooling of the heparin in the solution.
- Heparin sodium is not effective by oral administration and should be given by intermittent intravenous injection, intravenous infusion, or deep subcutaneous (intrafat, i.e., above the iliac crest or abdominal fat layer) injection. The intramuscular route of administration should be avoided because of the frequent occurrence of hematoma at the injection site.
- The dosage of heparin sodium should be adjusted according to the patient's coagulation test results. When heparin is given by continuous intravenous infusion, the coagulation time should be determined approximately every 4 hours in the early stages of treatment. When the drug is administered intermittently by intravenous injection, coagulation tests should be performed before each injection during the early stages of treatment and at appropriate intervals thereafter. Dosage is considered adequate when the activated partial thromboplastin time (APTT) is 1.5 to 2 times normal or when the whole blood clotting time is elevated approximately 2.5 to 3 times the control value. After deep subcutaneous (intrafat) injections, tests for adequacy of dosage are best performed on samples drawn 4–6 hours after the injections.
- Periodic platelet counts, hematocrits, and tests for occult blood in stool are recommended during the entire course of heparin therapy, regardless of the route of administration.
- Heparin Sodium Injection should not be mixed with doxorubicin, droperidol, ciprofloxacin, or mitoxantrone, since it has been reported that these drugs are incompatible with heparin and a precipitate may form.
Converting to Oral Anticoagulant
- When an oral anticoagulant of the coumarin or similar type is to be begun in patients already receiving heparin sodium, baseline and subsequent tests of prothrombin activity must be determined at a time when heparin activity is too low to affect the prothrombin time. This is about 5 hours after the last I.V. bolus and 24 hours after the last subcutaneous dose. If continuous I.V. heparin infusion is used, prothrombin time can usually be measured at any time.
- In converting from heparin to an oral anticoagulant, the dose of the oral anticoagulant should be the usual initial amount and thereafter prothrombin time should be determined at the usual intervals. To ensure continuous anticoagulation, it is advisable to continue full heparin therapy for several days after the prothrombin time has reached the therapeutic range. Heparin therapy may then be discontinued without tapering.
Therapeutic Anticoagulant Effect with Full-Dose Heparin
- Although dosage must be adjusted for the individual patient according to the results of suitable laboratory tests, the following dosage schedules may be used as guidelines:
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Heparin in adult patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Heparin in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
# Indications
- Heparin Sodium Injection is indicated for:
- Anticoagulant therapy in prophylaxis and treatment of venous thrombosis and its extension;
- (In a low-dose regimen) for prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdomino-thoracic surgery or who for other reasons are at risk of developing thromboembolic disease;
- Prophylaxis and treatment of pulmonary embolism;
- Atrial fibrillation with embolization;
- Diagnosis and treatment of acute and chronic consumption coagulopathies (disseminated intravascular coagulation);
- Prevention of clotting in arterial and heart surgery;
- Prophylaxis and treatment of peripheral arterial embolism;
- As an anticoagulant in blood transfusions, extracorporeal circulation, and dialysis procedures and in blood samples for laboratory purposes.
# Dosage
- Follow recommendations of appropriate pediatric reference texts. In general, the following dosage schedule may be used as a guideline:
- Initial Dose:
- 50 units/kg (I.V., drip)
- Maintenance Dose:
- 100 units/kg (I.V., drip) every four hours, or
20,000 units/M2/24 hours continuously
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Heparin in pediatric patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Heparin in pediatric patients.
# Contraindications
- Heparin sodium should not be used in patients:
- With severe thrombocytopenia;
- In whom suitable blood coagulation tests — e.g., the whole blood clotting time, partial thromboplastin time, etc. — cannot be performed at appropriate intervals (this contraindication refers to full-dose heparin; there is usually no need to monitor coagulation parameters in patients receiving low-dose heparin);
- With an uncontrollable active bleeding state, except when this is due to disseminated intravascular coagulation.
# Warnings
- Heparin is not intended for intramuscular use.
- Hypersensitivity: Patients with documented hypersensitivity to heparin should be given the drug only in clearly life-threatening situations.
- Hemorrhage: Hemorrhage can occur at virtually any site in patients receiving heparin. An unexplained fall in hematocrit, fall in blood pressure or any other unexplained symptom should lead to serious consideration of a hemorrhagic event.
- Heparin sodium should be used with extreme caution in disease states in which there is increased danger of hemorrhage. Some of the conditions in which increased danger of hemorrhage exists are:
- Cardiovascular — Subacute bacterial endocarditis. Severe hypertension.
- Surgical — During and immediately following (a) spinal tap or spinal anesthesia or (b) major surgery, especially involving the brain, spinal cord or eye.
- Hematology — Conditions associated with increased bleeding tendencies, such as hemophilia, thrombocytopenia, and some vascular purpuras.
- Gastrointestinal — Ulcerative lesions and continuous tube drainage of the stomach or small intestine.
- Other — Menstruation, liver disease with impaired hemostasis.
- Coagulation Testing: When heparin sodium is administered in therapeutic amounts, its dosage should be regulated by frequent blood coagulation tests. If the coagulation test is unduly prolonged or if hemorrhage occurs, heparin sodium should be discontinued promptly.
- Thrombocytopenia: thrombocytopenia in patients receiving heparin has been reported at frequencies up to 30%. It can occur 2 to 20 days (average 5 to 9) following the onset of heparin therapy. Obtain platelet counts before and periodically during heparin therapy. Monitor thrombocytopenia of any degree closely. If the count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant (see Heparin-Induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis).
- Heparin-Induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis: Heparin-induced thrombocytopenia (HIT) is a serious antibody-mediated reaction resulting from irreversible aggregation of platelets. HIT may progress to the development of venous and arterial thromboses, a condition known as heparin-induced thrombocytopenia and thrombosis (HITT). Thrombotic events may also be the initial presentation for HITT. These serious thromboembolic events include deep vein thrombosis, pulmonary embolism, cerebral vein thrombosis, limb ischemia, stroke, myocardial infarction, mesenteric thrombosis, renal arterial thrombosis, skin necrosis, gangrene of the extremities that may lead to amputation, and possibly death. Monitor thrombocytopenia of any degree closely. If the platelet count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant.
- HIT and HITT can occur up to several weeks after the discontinuation of heparin therapy. Patients presenting with thrombocytopenia or thrombosis after discontinuation of heparin should be evaluated for HIT and HITT.
- Solutions containing sodium ions should be used with great care, if at all, in patients with congestive heart failure, severe renal insufficiency and in clinical states in which there exists edema with sodium retention.
- The intravenous administration of these solutions can cause fluid and/or solute overloading resulting in dilution of serum electrolyte concentrations, overhydration, congested states or pulmonary edema.
- The risk of dilutional states is inversely proportional to the electrolyte concentrations of administered parenteral solutions. The risk of solute overload causing congested states with peripheral and pulmonary edema is directly proportional to the electrolyte concentrations of such solutions.
- In patients with diminished renal function, administration of solutions containing sodium ions may result in sodium retention.
- Excessive administration of potassium-free solutions may result in significant hypokalemia.
- As the dosage of solutions of heparin sodium must be titrated to individual patient response, additive medications should not be delivered via this solution.
## PRECAUTIONS
### General
- Increased resistance to heparin is frequently encountered in fever, thrombosis, thrombophlebitis, infections with thrombosing tendencies, myocardial infarction, cancer and in postsurgical patients.
- A higher incidence of bleeding has been reported in patients, particularly women, over 60 years of age.
- Laboratory Tests: Periodic platelet counts, hematocrits and tests for occult blood in stool are recommended during the entire course of heparin therapy, regardless of the route of administration.
# Adverse Reactions
## Clinical Trials Experience
- Hemorrhage: Hemorrhage is the chief complication that may result from heparin therapy. An overly prolonged clotting time or minor bleeding during therapy can usually be controlled by withdrawing the drug. It should be appreciated that gastrointestinal or urinary tract bleeding during anticoagulant therapy may indicate the presence of an underlying occult lesion. Bleeding can occur at any site but certain specific hemorrhagic complications may be difficult to detect:
- Adrenal hemorrhage, with resultant acute adrenal insufficiency, has occurred during anticoagulant therapy. Therefore, such treatment should be discontinued in patients who develop signs and symptoms of acute adrenal hemorrhage and insufficiency. Initiation of corrective therapy should not depend on laboratory confirmation of the diagnosis, since any delay in an acute situation may result in the patient’s death.
- Ovarian (corpus luteum) hemorrhage developed in a number of women of reproductive age receiving short- or long-term anticoagulant therapy. This complication if unrecognized may be fatal.
- Retroperitoneal hemorrhage.
- Local Irritation: Local irritation, erythema, mild pain, hematoma or ulceration may follow deep subcutaneous (intrafat) injection of heparin sodium. These complications are much more common after intramuscular use, and such use is not recommended.
- Hypersensitivity: Generalized hypersensitivity reactions have been reported with chills, fever, and urticaria as the most usual manifestations, and asthma, rhinitis, lacrimation, headache, nausea and vomiting, and anaphylactoid reactions, including shock, occurring more rarely. Itching and burning, especially on the plantar site of the feet, may occur.
- Thrombocytopenia has been reported to occur in patients receiving heparin with a reported incidence of 0 to 30%. While often mild and of no obvious clinical significance, such thrombocytopenia can be accompanied by severe thromboembolic complications such as skin necrosis, gangrene of the extremities that may lead to amputation, myocardial infarction, pulmonary embolism, stroke, and possibly death.
- Certain episodes of painful, ischemic and cyanosed limbs have in the past been attributed to allergic vasospastic reactions. Whether these are in fact identical to the thrombocytopenia associated complications remains to be determined.
- Miscellaneous: Osteoporosis following long-term administration of high doses of heparin, cutaneous necrosis after systemic administration, suppression of aldosterone synthesis, delayed transient alopecia, priapism and rebound hyperlipemia on discontinuation of heparin sodium have also been reported.
- Significant elevations of aminotransferase (SGOT and SGPT ) levels have occurred in a high percentage of patients (and healthy subjects) who have received heparin.
- Reactions which may occur because of the solution or the technique of administration include febrile response, infection at the site of injection, venous thrombosis or phlebitis extending from the site of injection, extravasation and hypervolemia.
- If an adverse reaction does occur, discontinue the infusion, evaluate the patient, institute appropriate therapeutic countermeasures and save the remainder of the fluid for examination if deemed necessary.
## Postmarketing Experience
- FDA Package Insert for Heparin contains no information regarding post marketing Adverse Reactions.
# Drug Interactions
Oral anticoagulants: Heparin sodium may prolong the one-stage prothrombin time. Therefore, when heparin sodium is given with dicumarol or warfarin sodium, a period of at least 5 hours after the last intravenous dose should elapse before blood is drawn if a valid PROTHROMBIN time is to be obtained.
Platelet inhibitors: Drugs such as acetylsalicylic acid, dextran, phenylbutazone, ibuprofen, indomethacin, dipyridamole, hydroxychloroquine and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Other interactions: Digitalis, tetracyclines, nicotine, or antihistamines may partially counteract the anticoagulant action of heparin sodium.
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA): C
- There are no adequate and well-controlled studies on heparin use in pregnant women. In published reports, heparin exposure during pregnancy did not show evidence of an increased risk of adverse maternal or fetal outcomes in humans. Heparin sodium does not cross the placenta, based on human and animal studies. Administration of heparin to pregnant animals at doses higher than the maximum human daily dose based on body weight resulted in increased resorptions. Use heparin sodium during pregnancy only if the potential benefit justifies the potential risk to the fetus.
- In a published study conducted in rats and rabbits, pregnant animals received heparin intravenously during organogenesis at a dose of 10,000 units/kg/day, approximately 10 times the maximum human daily dose based on body weight. The number of early resorptions increased in both species.
- There was no evidence of teratogenic effects.
Pregnancy Category (AUS):
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Heparin in women who are pregnant.
### Labor and Delivery
- Due to its large molecular weight, heparin is not likely to be excreted in human milk, and any heparin in milk would not be orally absorbed by a nursing infant. Exercise caution when administering Heparin Sodium to a nursing mother.
### Nursing Mothers
There is no FDA guidance on the use of Heparin in women who are nursing.
### Pediatric Use
- There are no adequate and well controlled studies on heparin use in pediatric patients. Pediatric dosing recommendations are based on clinical experience.
### Geriatic Use
- A higher incidence of bleeding has been reported in patients over 60 years of age, especially women (see PRECAUTIONS, General). Clinical studies indicate that lower doses of heparin may be indicated in these patients.
### Gender
- There is no FDA guidance on the use of Heparin with respect to specific gender populations.
### Race
- There is no FDA guidance on the use of Heparin with respect to specific racial populations.
### Renal Impairment
- There is no FDA guidance on the use of Heparin in patients with renal impairment.
### Hepatic Impairment
- There is no FDA guidance on the use of Heparin in patients with hepatic impairment.
### Females of Reproductive Potential and Males
- There is no FDA guidance on the use of Heparin in women of reproductive potentials and males.
### Immunocompromised Patients
- There is no FDA guidance one the use of Heparin in patients who are immunocompromised.
### Others
# Administration and Monitoring
### Administration
- Intravenous
- Subcutaneous
### Monitoring
- FDA Package Insert for Heparin contains no information regarding drug monitoring.
# IV Compatibility
- There is limited information about the IV Compatibility.
# Overdosage
- Symptoms: Bleeding is the chief sign of heparin overdosage. Nosebleeds, blood in urine or tarry stools may be noted as the first sign of bleeding. Easy bruising or petechial formations may precede frank bleeding.
- Treatment: Neutralization of heparin effect.
- When clinical circumstances (bleeding) require reversal of heparinization, protamine sulfate (1% solution) by slow infusion will neutralize heparin sodium. No more than 50 mg should be administered, very slowly in any 10 minute period. Each mg of protamine sulfate neutralizes approximately 100 USP units. The amount of protamine required decreases over time as heparin is metabolized. Although the metabolism of heparin is complex, it may, for the purpose of choosing a protamine dose, be assumed to have a half-life of about ½ hour after intravenous injection.
- Administration of protamine sulfate can cause severe hypotensive and anaphylactoid reactions. Because fatal reactions often resembling anaphylaxis have been reported, the drug should be given only when resuscitation techniques and treatment of anaphylactoid shock are readily available.
- For additional information, the labeling of Protamine Sulfate Injection, USP products should be consulted.
- In the event of overhydration or solute overload, re-evaluate the patient and institute appropriate corrective measures.
# Pharmacology
## Mechanism of Action
- There is limited information about the mechanism of action.
## Structure
- Intravenous solutions with heparin sodium (derived from porcine intestinal mucosa) are sterile, nonpyrogenic fluids for intravenous administration. They contain no bacteriostat or antimicrobial agent or added buffer. Edetate disodium, anhydrous is added as a stabilizer. The solution may contain sodium hydroxide and/or hydrochloric acid for pH adjustment. See Table for summary of contents and characteristics of these solutions.
- Heparin Sodium, USP is a heterogenous group of straight-chain anionic mucopolysaccharides, called glycosaminoglycans having anticoagulant properties. Although others may be present, the main sugars occurring in heparin are: (1) α- L-iduronic acid 2-sulfate, (2) 2-deoxy-2-sulfamino-α-D-glucose 6-sulfate, (3) β-D-glucuronic acid, (4) 2-acetamido-2-deoxy-α-D-glucose, and (5) α-L-iduronic acid. These sugars are present in decreasing amounts, usually in the order (2) > (1) > (4) > (3) > (5), and are joined by glycosidic linkages, forming polymers of varying sizes. Heparin is strongly acidic because of its content of covalently linked sulfate and carboxylic acid groups. In heparin sodium, the acidic protons of the sulfate units are partially replaced by sodium ions. The potency is determined by a biological assay using a USP reference standard based on units of heparin activity per milligram.
- Structure of Heparin Sodium (representative subunits):
- Sodium Chloride, USP is chemically designated NaCl, a white crystalline compound freely soluble in water.
Water for Injection, USP is chemically designated H2O.
- The flexible plastic container is fabricated from a specially formulated polyvinyl chloride. Water can permeate from inside the container into the overwrap but not in amounts sufficient to affect the solution significantly. Solutions inside the plastic container also can leach out certain of its chemical components in very small amounts before the expiration period is attained. However, the safety of the plastic has been confirmed by tests in animals according to USP biological standards for plastic containers.
## Pharmacodynamics
- Heparin inhibits reactions that lead to the clotting of blood and the formation of fibrin clots both in vitro and in vivo. Heparin acts at multiple sites in the normal coagulation system. Small amounts of heparin in combination with antithrombin III (heparin cofactor) can inhibit thrombosis by inactivating activated Factor X and inhibiting the conversion of prothrombin to thrombin. Once active thrombosis has developed, larger amounts of heparin can inhibit further coagulation by inactivating thrombin and preventing the conversion of fibrinogen to fibrin. Heparin also prevents the formation of a stable fibrin clot in inhibiting the activation of the fibrin stabilizing factor.
- Bleeding time is usually unaffected by heparin. Clotting time is prolonged by full therapeutic doses of heparin; in most cases, it is not measurably affected by low doses of heparin.
- Patients over 60 years of age, following similar doses of heparin, may have higher plasma levels of heparin and longer activated partial thromboplastin times (APTTs) compared with patients under 60 years of age.
- Peak plasma levels of heparin are achieved 2 to 4 hours following subcutaneous administration, although there are considerable individual variations. Loglinear plots of heparin plasma concentrations with time for a wide range of dose levels are linear which suggests the absence of zero order processes. Liver and the reticuloendothelial system are the site of biotransformation. The biphasic elimination curve, a rapidly declining alpha phase (t½ = 10 min) and after the age of 40 a slower beta phase, indicates uptake in organs. The absence of a relationship between anticoagulant half-life and concentration half-life may reflect factors such as protein binding of heparin.
- Heparin does not have fibrinolytic activity; therefore, it will not lyse existing clots.
## Pharmacokinetics
- Hypotonic concentrations of sodium chloride are suited for parenteral maintenance of water requirements when only small quantities of salt are desired.
- Sodium chloride in water dissociates to provide sodium (Na+) and chloride (Cl¯) ions. Sodium (Na+) is the principal cation of the extracellular fluid and plays a large part in the therapy of fluid and electrolyte disturbances. Chloride (Cl¯) has an integral role in buffering action when oxygen and carbon dioxide exchange occurs in the red blood cells. The distribution and excretion of sodium (Na+) are largely under the control of the kidney which maintains a balance between intake and output.
- Water is an essential constituent of all body tissues and accounts for approximately 70% of total body weight.
- Average normal adult daily requirements range from two to three liters (1.0 to 1.5 liters each for insensible water loss by perspiration and urine production).
- Water balance is maintained by various regulatory mechanisms. Water distribution depends primarily on the concentration of electrolytes in the body compartments and sodium (Na+) plays a major role in maintaining physiologic equilibrium.
## Nonclinical Toxicology
- Carcinogenesis, Mutagenesis, Impairment of Fertility: No long-term studies in animals have been performed to evaluate carcinogenic potential of heparin. Also, no reproduction studies in animals have been performed concerning mutagenesis or impairment of fertility.
# Clinical Studies
FDA Package Insert for Heparin contains no information regarding Clinical Studies.
# How Supplied
- Intravenous solutions with heparin sodium are available in single-dose flexible plastic containers in varied sizes and concentrations as shown in the accompanying Table as follows:
For the above Heparin Sodium products the pH range is 6.1 (5.0 – 7.5) and the osmolarity mOsmol/L (calc.) is 155.
## Storage
- Store at 20 to 25°C (68 to 77°F).Protect from freezing.
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
- FDA Package Insert for Heparin contains no information regarding Patient information.
# Precautions with Alcohol
- Alcohol-Heparin interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- Heparin sodium
# Look-Alike Drug Names
There is limited information regarding Heparin Look-Alike Drug Names in the drug label.
# Drug Shortage Status
# Price | Heparin
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
# Overview
Heparin is an unfractionated heparin that is FDA approved for the treatment of atrial fibrillation and disseminated intravascular coagulation; It is used as a prophylaxis for pulmonary embolism, thrombosis,venous catheter occlusion and
venous thromboembolism.. Common adverse reactions include thrombocytopenia and increased liver aminotransferase level.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
# Indications
- Heparin Sodium Injection is indicated for:
- Anticoagulant therapy in prophylaxis and treatment of venous thrombosis and its extension;
- (In a low-dose regimen) for prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdomino-thoracic surgery or who for other reasons are at risk of developing thromboembolic disease;
- Prophylaxis and treatment of pulmonary embolism;
- Atrial fibrillation with embolization;
- Diagnosis and treatment of acute and chronic consumption coagulopathies (disseminated intravascular coagulation);
- Prevention of clotting in arterial and heart surgery;
- Prophylaxis and treatment of peripheral arterial embolism;
- As an anticoagulant in blood transfusions, extracorporeal circulation, and dialysis procedures and in blood samples for laboratory purposes.
# Dosage
- Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Slight discoloration does not alter potency.
- When heparin is added to an infusion solution for continuous intravenous administration, the container should be inverted at least six times to ensure adequate mixing and prevent pooling of the heparin in the solution.
- Heparin sodium is not effective by oral administration and should be given by intermittent intravenous injection, intravenous infusion, or deep subcutaneous (intrafat, i.e., above the iliac crest or abdominal fat layer) injection. The intramuscular route of administration should be avoided because of the frequent occurrence of hematoma at the injection site.
- The dosage of heparin sodium should be adjusted according to the patient's coagulation test results. When heparin is given by continuous intravenous infusion, the coagulation time should be determined approximately every 4 hours in the early stages of treatment. When the drug is administered intermittently by intravenous injection, coagulation tests should be performed before each injection during the early stages of treatment and at appropriate intervals thereafter. Dosage is considered adequate when the activated partial thromboplastin time (APTT) is 1.5 to 2 times normal or when the whole blood clotting time is elevated approximately 2.5 to 3 times the control value. After deep subcutaneous (intrafat) injections, tests for adequacy of dosage are best performed on samples drawn 4–6 hours after the injections.
- Periodic platelet counts, hematocrits, and tests for occult blood in stool are recommended during the entire course of heparin therapy, regardless of the route of administration.
- Heparin Sodium Injection should not be mixed with doxorubicin, droperidol, ciprofloxacin, or mitoxantrone, since it has been reported that these drugs are incompatible with heparin and a precipitate may form.
Converting to Oral Anticoagulant
- When an oral anticoagulant of the coumarin or similar type is to be begun in patients already receiving heparin sodium, baseline and subsequent tests of prothrombin activity must be determined at a time when heparin activity is too low to affect the prothrombin time. This is about 5 hours after the last I.V. bolus and 24 hours after the last subcutaneous dose. If continuous I.V. heparin infusion is used, prothrombin time can usually be measured at any time.
- In converting from heparin to an oral anticoagulant, the dose of the oral anticoagulant should be the usual initial amount and thereafter prothrombin time should be determined at the usual intervals. To ensure continuous anticoagulation, it is advisable to continue full heparin therapy for several days after the prothrombin time has reached the therapeutic range. Heparin therapy may then be discontinued without tapering.
Therapeutic Anticoagulant Effect with Full-Dose Heparin
- Although dosage must be adjusted for the individual patient according to the results of suitable laboratory tests, the following dosage schedules may be used as guidelines:
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Heparin in adult patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Heparin in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
# Indications
- Heparin Sodium Injection is indicated for:
- Anticoagulant therapy in prophylaxis and treatment of venous thrombosis and its extension;
- (In a low-dose regimen) for prevention of postoperative deep venous thrombosis and pulmonary embolism in patients undergoing major abdomino-thoracic surgery or who for other reasons are at risk of developing thromboembolic disease;
- Prophylaxis and treatment of pulmonary embolism;
- Atrial fibrillation with embolization;
- Diagnosis and treatment of acute and chronic consumption coagulopathies (disseminated intravascular coagulation);
- Prevention of clotting in arterial and heart surgery;
- Prophylaxis and treatment of peripheral arterial embolism;
- As an anticoagulant in blood transfusions, extracorporeal circulation, and dialysis procedures and in blood samples for laboratory purposes.
# Dosage
- Follow recommendations of appropriate pediatric reference texts. In general, the following dosage schedule may be used as a guideline:
- Initial Dose:
- 50 units/kg (I.V., drip)
- Maintenance Dose:
- 100 units/kg (I.V., drip) every four hours, or
20,000 units/M2/24 hours continuously
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Heparin in pediatric patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Heparin in pediatric patients.
# Contraindications
- Heparin sodium should not be used in patients:
- With severe thrombocytopenia;
- In whom suitable blood coagulation tests — e.g., the whole blood clotting time, partial thromboplastin time, etc. — cannot be performed at appropriate intervals (this contraindication refers to full-dose heparin; there is usually no need to monitor coagulation parameters in patients receiving low-dose heparin);
- With an uncontrollable active bleeding state, except when this is due to disseminated intravascular coagulation.
# Warnings
- Heparin is not intended for intramuscular use.
- Hypersensitivity: Patients with documented hypersensitivity to heparin should be given the drug only in clearly life-threatening situations.
- Hemorrhage: Hemorrhage can occur at virtually any site in patients receiving heparin. An unexplained fall in hematocrit, fall in blood pressure or any other unexplained symptom should lead to serious consideration of a hemorrhagic event.
- Heparin sodium should be used with extreme caution in disease states in which there is increased danger of hemorrhage. Some of the conditions in which increased danger of hemorrhage exists are:
- Cardiovascular — Subacute bacterial endocarditis. Severe hypertension.
- Surgical — During and immediately following (a) spinal tap or spinal anesthesia or (b) major surgery, especially involving the brain, spinal cord or eye.
- Hematology — Conditions associated with increased bleeding tendencies, such as hemophilia, thrombocytopenia, and some vascular purpuras.
- Gastrointestinal — Ulcerative lesions and continuous tube drainage of the stomach or small intestine.
- Other — Menstruation, liver disease with impaired hemostasis.
- Coagulation Testing: When heparin sodium is administered in therapeutic amounts, its dosage should be regulated by frequent blood coagulation tests. If the coagulation test is unduly prolonged or if hemorrhage occurs, heparin sodium should be discontinued promptly.
- Thrombocytopenia: thrombocytopenia in patients receiving heparin has been reported at frequencies up to 30%. It can occur 2 to 20 days (average 5 to 9) following the onset of heparin therapy. Obtain platelet counts before and periodically during heparin therapy. Monitor thrombocytopenia of any degree closely. If the count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant (see Heparin-Induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis).
- Heparin-Induced Thrombocytopenia and Heparin-Induced Thrombocytopenia and Thrombosis: Heparin-induced thrombocytopenia (HIT) is a serious antibody-mediated reaction resulting from irreversible aggregation of platelets. HIT may progress to the development of venous and arterial thromboses, a condition known as heparin-induced thrombocytopenia and thrombosis (HITT). Thrombotic events may also be the initial presentation for HITT. These serious thromboembolic events include deep vein thrombosis, pulmonary embolism, cerebral vein thrombosis, limb ischemia, stroke, myocardial infarction, mesenteric thrombosis, renal arterial thrombosis, skin necrosis, gangrene of the extremities that may lead to amputation, and possibly death. Monitor thrombocytopenia of any degree closely. If the platelet count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant.
- HIT and HITT can occur up to several weeks after the discontinuation of heparin therapy. Patients presenting with thrombocytopenia or thrombosis after discontinuation of heparin should be evaluated for HIT and HITT.
- Solutions containing sodium ions should be used with great care, if at all, in patients with congestive heart failure, severe renal insufficiency and in clinical states in which there exists edema with sodium retention.
- The intravenous administration of these solutions can cause fluid and/or solute overloading resulting in dilution of serum electrolyte concentrations, overhydration, congested states or pulmonary edema.
- The risk of dilutional states is inversely proportional to the electrolyte concentrations of administered parenteral solutions. The risk of solute overload causing congested states with peripheral and pulmonary edema is directly proportional to the electrolyte concentrations of such solutions.
- In patients with diminished renal function, administration of solutions containing sodium ions may result in sodium retention.
- Excessive administration of potassium-free solutions may result in significant hypokalemia.
- As the dosage of solutions of heparin sodium must be titrated to individual patient response, additive medications should not be delivered via this solution.
## PRECAUTIONS
### General
- Increased resistance to heparin is frequently encountered in fever, thrombosis, thrombophlebitis, infections with thrombosing tendencies, myocardial infarction, cancer and in postsurgical patients.
- A higher incidence of bleeding has been reported in patients, particularly women, over 60 years of age.
- Laboratory Tests: Periodic platelet counts, hematocrits and tests for occult blood in stool are recommended during the entire course of heparin therapy, regardless of the route of administration.
# Adverse Reactions
## Clinical Trials Experience
- Hemorrhage: Hemorrhage is the chief complication that may result from heparin therapy. An overly prolonged clotting time or minor bleeding during therapy can usually be controlled by withdrawing the drug. It should be appreciated that gastrointestinal or urinary tract bleeding during anticoagulant therapy may indicate the presence of an underlying occult lesion. Bleeding can occur at any site but certain specific hemorrhagic complications may be difficult to detect:
- Adrenal hemorrhage, with resultant acute adrenal insufficiency, has occurred during anticoagulant therapy. Therefore, such treatment should be discontinued in patients who develop signs and symptoms of acute adrenal hemorrhage and insufficiency. Initiation of corrective therapy should not depend on laboratory confirmation of the diagnosis, since any delay in an acute situation may result in the patient’s death.
- Ovarian (corpus luteum) hemorrhage developed in a number of women of reproductive age receiving short- or long-term anticoagulant therapy. This complication if unrecognized may be fatal.
- Retroperitoneal hemorrhage.
- Local Irritation: Local irritation, erythema, mild pain, hematoma or ulceration may follow deep subcutaneous (intrafat) injection of heparin sodium. These complications are much more common after intramuscular use, and such use is not recommended.
- Hypersensitivity: Generalized hypersensitivity reactions have been reported with chills, fever, and urticaria as the most usual manifestations, and asthma, rhinitis, lacrimation, headache, nausea and vomiting, and anaphylactoid reactions, including shock, occurring more rarely. Itching and burning, especially on the plantar site of the feet, may occur.
- Thrombocytopenia has been reported to occur in patients receiving heparin with a reported incidence of 0 to 30%. While often mild and of no obvious clinical significance, such thrombocytopenia can be accompanied by severe thromboembolic complications such as skin necrosis, gangrene of the extremities that may lead to amputation, myocardial infarction, pulmonary embolism, stroke, and possibly death.
- Certain episodes of painful, ischemic and cyanosed limbs have in the past been attributed to allergic vasospastic reactions. Whether these are in fact identical to the thrombocytopenia associated complications remains to be determined.
- Miscellaneous: Osteoporosis following long-term administration of high doses of heparin, cutaneous necrosis after systemic administration, suppression of aldosterone synthesis, delayed transient alopecia, priapism and rebound hyperlipemia on discontinuation of heparin sodium have also been reported.
- Significant elevations of aminotransferase (SGOT [S-AST] and SGPT [S-ALT]) levels have occurred in a high percentage of patients (and healthy subjects) who have received heparin.
- Reactions which may occur because of the solution or the technique of administration include febrile response, infection at the site of injection, venous thrombosis or phlebitis extending from the site of injection, extravasation and hypervolemia.
- If an adverse reaction does occur, discontinue the infusion, evaluate the patient, institute appropriate therapeutic countermeasures and save the remainder of the fluid for examination if deemed necessary.
## Postmarketing Experience
- FDA Package Insert for Heparin contains no information regarding post marketing Adverse Reactions.
# Drug Interactions
Oral anticoagulants: Heparin sodium may prolong the one-stage prothrombin time. Therefore, when heparin sodium is given with dicumarol or warfarin sodium, a period of at least 5 hours after the last intravenous dose should elapse before blood is drawn if a valid PROTHROMBIN time is to be obtained.
Platelet inhibitors: Drugs such as acetylsalicylic acid, dextran, phenylbutazone, ibuprofen, indomethacin, dipyridamole, hydroxychloroquine and others that interfere with platelet-aggregation reactions (the main hemostatic defense of heparinized patients) may induce bleeding and should be used with caution in patients receiving heparin sodium.
Other interactions: Digitalis, tetracyclines, nicotine, or antihistamines may partially counteract the anticoagulant action of heparin sodium.
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA): C
- There are no adequate and well-controlled studies on heparin use in pregnant women. In published reports, heparin exposure during pregnancy did not show evidence of an increased risk of adverse maternal or fetal outcomes in humans. Heparin sodium does not cross the placenta, based on human and animal studies. Administration of heparin to pregnant animals at doses higher than the maximum human daily dose based on body weight resulted in increased resorptions. Use heparin sodium during pregnancy only if the potential benefit justifies the potential risk to the fetus.
- In a published study conducted in rats and rabbits, pregnant animals received heparin intravenously during organogenesis at a dose of 10,000 units/kg/day, approximately 10 times the maximum human daily dose based on body weight. The number of early resorptions increased in both species.
- There was no evidence of teratogenic effects.
Pregnancy Category (AUS):
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Heparin in women who are pregnant.
### Labor and Delivery
- Due to its large molecular weight, heparin is not likely to be excreted in human milk, and any heparin in milk would not be orally absorbed by a nursing infant. Exercise caution when administering Heparin Sodium to a nursing mother.
### Nursing Mothers
There is no FDA guidance on the use of Heparin in women who are nursing.
### Pediatric Use
- There are no adequate and well controlled studies on heparin use in pediatric patients. Pediatric dosing recommendations are based on clinical experience.
### Geriatic Use
- A higher incidence of bleeding has been reported in patients over 60 years of age, especially women (see PRECAUTIONS, General). Clinical studies indicate that lower doses of heparin may be indicated in these patients.
### Gender
- There is no FDA guidance on the use of Heparin with respect to specific gender populations.
### Race
- There is no FDA guidance on the use of Heparin with respect to specific racial populations.
### Renal Impairment
- There is no FDA guidance on the use of Heparin in patients with renal impairment.
### Hepatic Impairment
- There is no FDA guidance on the use of Heparin in patients with hepatic impairment.
### Females of Reproductive Potential and Males
- There is no FDA guidance on the use of Heparin in women of reproductive potentials and males.
### Immunocompromised Patients
- There is no FDA guidance one the use of Heparin in patients who are immunocompromised.
### Others
# Administration and Monitoring
### Administration
- Intravenous
- Subcutaneous
### Monitoring
- FDA Package Insert for Heparin contains no information regarding drug monitoring.
# IV Compatibility
- There is limited information about the IV Compatibility.
# Overdosage
- Symptoms: Bleeding is the chief sign of heparin overdosage. Nosebleeds, blood in urine or tarry stools may be noted as the first sign of bleeding. Easy bruising or petechial formations may precede frank bleeding.
- Treatment: Neutralization of heparin effect.
- When clinical circumstances (bleeding) require reversal of heparinization, protamine sulfate (1% solution) by slow infusion will neutralize heparin sodium. No more than 50 mg should be administered, very slowly in any 10 minute period. Each mg of protamine sulfate neutralizes approximately 100 USP units. The amount of protamine required decreases over time as heparin is metabolized. Although the metabolism of heparin is complex, it may, for the purpose of choosing a protamine dose, be assumed to have a half-life of about ½ hour after intravenous injection.
- Administration of protamine sulfate can cause severe hypotensive and anaphylactoid reactions. Because fatal reactions often resembling anaphylaxis have been reported, the drug should be given only when resuscitation techniques and treatment of anaphylactoid shock are readily available.
- For additional information, the labeling of Protamine Sulfate Injection, USP products should be consulted.
- In the event of overhydration or solute overload, re-evaluate the patient and institute appropriate corrective measures.
# Pharmacology
## Mechanism of Action
- There is limited information about the mechanism of action.
## Structure
- Intravenous solutions with heparin sodium (derived from porcine intestinal mucosa) are sterile, nonpyrogenic fluids for intravenous administration. They contain no bacteriostat or antimicrobial agent or added buffer. Edetate disodium, anhydrous is added as a stabilizer. The solution may contain sodium hydroxide and/or hydrochloric acid for pH adjustment. See Table for summary of contents and characteristics of these solutions.
- Heparin Sodium, USP is a heterogenous group of straight-chain anionic mucopolysaccharides, called glycosaminoglycans having anticoagulant properties. Although others may be present, the main sugars occurring in heparin are: (1) α- L-iduronic acid 2-sulfate, (2) 2-deoxy-2-sulfamino-α-D-glucose 6-sulfate, (3) β-D-glucuronic acid, (4) 2-acetamido-2-deoxy-α-D-glucose, and (5) α-L-iduronic acid. These sugars are present in decreasing amounts, usually in the order (2) > (1) > (4) > (3) > (5), and are joined by glycosidic linkages, forming polymers of varying sizes. Heparin is strongly acidic because of its content of covalently linked sulfate and carboxylic acid groups. In heparin sodium, the acidic protons of the sulfate units are partially replaced by sodium ions. The potency is determined by a biological assay using a USP reference standard based on units of heparin activity per milligram.
- Structure of Heparin Sodium (representative subunits):
- Sodium Chloride, USP is chemically designated NaCl, a white crystalline compound freely soluble in water.
Water for Injection, USP is chemically designated H2O.
- The flexible plastic container is fabricated from a specially formulated polyvinyl chloride. Water can permeate from inside the container into the overwrap but not in amounts sufficient to affect the solution significantly. Solutions inside the plastic container also can leach out certain of its chemical components in very small amounts before the expiration period is attained. However, the safety of the plastic has been confirmed by tests in animals according to USP biological standards for plastic containers.
## Pharmacodynamics
- Heparin inhibits reactions that lead to the clotting of blood and the formation of fibrin clots both in vitro and in vivo. Heparin acts at multiple sites in the normal coagulation system. Small amounts of heparin in combination with antithrombin III (heparin cofactor) can inhibit thrombosis by inactivating activated Factor X and inhibiting the conversion of prothrombin to thrombin. Once active thrombosis has developed, larger amounts of heparin can inhibit further coagulation by inactivating thrombin and preventing the conversion of fibrinogen to fibrin. Heparin also prevents the formation of a stable fibrin clot in inhibiting the activation of the fibrin stabilizing factor.
- Bleeding time is usually unaffected by heparin. Clotting time is prolonged by full therapeutic doses of heparin; in most cases, it is not measurably affected by low doses of heparin.
- Patients over 60 years of age, following similar doses of heparin, may have higher plasma levels of heparin and longer activated partial thromboplastin times (APTTs) compared with patients under 60 years of age.
- Peak plasma levels of heparin are achieved 2 to 4 hours following subcutaneous administration, although there are considerable individual variations. Loglinear plots of heparin plasma concentrations with time for a wide range of dose levels are linear which suggests the absence of zero order processes. Liver and the reticuloendothelial system are the site of biotransformation. The biphasic elimination curve, a rapidly declining alpha phase (t½ = 10 min) and after the age of 40 a slower beta phase, indicates uptake in organs. The absence of a relationship between anticoagulant half-life and concentration half-life may reflect factors such as protein binding of heparin.
- Heparin does not have fibrinolytic activity; therefore, it will not lyse existing clots.
## Pharmacokinetics
- Hypotonic concentrations of sodium chloride are suited for parenteral maintenance of water requirements when only small quantities of salt are desired.
- Sodium chloride in water dissociates to provide sodium (Na+) and chloride (Cl¯) ions. Sodium (Na+) is the principal cation of the extracellular fluid and plays a large part in the therapy of fluid and electrolyte disturbances. Chloride (Cl¯) has an integral role in buffering action when oxygen and carbon dioxide exchange occurs in the red blood cells. The distribution and excretion of sodium (Na+) are largely under the control of the kidney which maintains a balance between intake and output.
- Water is an essential constituent of all body tissues and accounts for approximately 70% of total body weight.
- Average normal adult daily requirements range from two to three liters (1.0 to 1.5 liters each for insensible water loss by perspiration and urine production).
- Water balance is maintained by various regulatory mechanisms. Water distribution depends primarily on the concentration of electrolytes in the body compartments and sodium (Na+) plays a major role in maintaining physiologic equilibrium.
## Nonclinical Toxicology
- Carcinogenesis, Mutagenesis, Impairment of Fertility: No long-term studies in animals have been performed to evaluate carcinogenic potential of heparin. Also, no reproduction studies in animals have been performed concerning mutagenesis or impairment of fertility.
# Clinical Studies
FDA Package Insert for Heparin contains no information regarding Clinical Studies.
# How Supplied
- Intravenous solutions with heparin sodium are available in single-dose flexible plastic containers in varied sizes and concentrations as shown in the accompanying Table as follows:
For the above Heparin Sodium products the pH range is 6.1 (5.0 – 7.5) and the osmolarity mOsmol/L (calc.) is 155.
## Storage
- Store at 20 to 25°C (68 to 77°F).Protect from freezing.
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
- FDA Package Insert for Heparin contains no information regarding Patient information.
# Precautions with Alcohol
- Alcohol-Heparin interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- Heparin sodium
# Look-Alike Drug Names
There is limited information regarding Heparin Look-Alike Drug Names in the drug label.
# Drug Shortage Status
# Price | https://www.wikidoc.org/index.php/Hep-Lock | |
57ac7a02fdd2c213bf1f12e27b573a464ebb8ed6 | wikidoc | Hickory | Hickory
# Overview
Trees in the genus Carya (Template:Lang-grc "nut") are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts. Five or six species are native to China, Indochina, and India (State of Assam), 11 or 12 are from the United States, two to four are from Canada and four are found in Mexico.
Another Asian species, beaked hickory, previously listed as Carya sinensis, is now treated in a separate genus, Annamocarya, as Annamocarya sinensis.
# Species and classification
In the APG system, genus Carya (and the whole Juglandaceae family) has been recently moved to the Fagales order.
- Carya sect. Sinocarya – Asian hickories
Carya dabieshanensis M.C. Liu – Dabie Shan Hickory (may be synonymous with C. cathayensis)
Carya cathayensis Sarg. – Chinese Hickory
Carya hunanensis W.C.Cheng & R.H.Chang – Hunan Hickory
Carya kweichowensis Kuang & A.M.Lu – Guizhou Hickory
Carya poilanei Leroy - Poilane's Hickory
Carya tonkinensis Lecomte – Vietnamese Hickory
- Carya dabieshanensis M.C. Liu – Dabie Shan Hickory (may be synonymous with C. cathayensis)
- Carya cathayensis Sarg. – Chinese Hickory
- Carya hunanensis W.C.Cheng & R.H.Chang – Hunan Hickory
- Carya kweichowensis Kuang & A.M.Lu – Guizhou Hickory
- Carya poilanei Leroy - Poilane's Hickory
- Carya tonkinensis Lecomte – Vietnamese Hickory
- Carya sect. Carya – typical hickories
Carya floridana Sarg. – Scrub Hickory
Carya glabra (Mill.) Sweet – Pignut Hickory, Pignut, Sweet Pignut, Coast Pignut Hickory, Smoothbark Hickory, Swamp Hickory, Broom Hickory
Carya myristiciformis (F.Michx.) Nutt. – Nutmeg Hickory, Swamp Hickory, Bitter Water Hickory
Carya ovalis (Wangenh.) Sarg. – Red Hickory, Spicebark Hickory, Sweet Pignut Hickory (treated as a synonym of C. glabra by Flora N. Amer.)
Carya ovata (Mill.) K.Koch – Shagbark Hickory
Carya ovata var. ovata – Northern Shagbark Hickory
Carya ovata var. australis – Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
Carya laciniosa (Mill.) K.Koch – Shellbark Hickory, Shagbark Hickory, Bigleaf Shagbark Hickory, Kingnut, Big Shellbark, Bottom Shellbark, Thick Shellbark, Western Shellbark
Carya pallida (Ashe) Engl. & Graebn. – Sand Hickory
Carya texana Buckley – Black Hickory
Carya tomentosa (Poir.) Nutt. – Mockernut Hickory (syn. C. alba)
†Carya washingtonensis - Manchester Extinct Miocene
- Carya floridana Sarg. – Scrub Hickory
- Carya glabra (Mill.) Sweet – Pignut Hickory, Pignut, Sweet Pignut, Coast Pignut Hickory, Smoothbark Hickory, Swamp Hickory, Broom Hickory
- Carya myristiciformis (F.Michx.) Nutt. – Nutmeg Hickory, Swamp Hickory, Bitter Water Hickory
- Carya ovalis (Wangenh.) Sarg. – Red Hickory, Spicebark Hickory, Sweet Pignut Hickory (treated as a synonym of C. glabra by Flora N. Amer.)
- Carya ovata (Mill.) K.Koch – Shagbark Hickory
Carya ovata var. ovata – Northern Shagbark Hickory
Carya ovata var. australis – Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
- Carya ovata var. ovata – Northern Shagbark Hickory
- Carya ovata var. australis – Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
- Carya laciniosa (Mill.) K.Koch – Shellbark Hickory, Shagbark Hickory, Bigleaf Shagbark Hickory, Kingnut, Big Shellbark, Bottom Shellbark, Thick Shellbark, Western Shellbark
- Carya pallida (Ashe) Engl. & Graebn. – Sand Hickory
- Carya texana Buckley – Black Hickory
- Carya tomentosa (Poir.) Nutt. – Mockernut Hickory (syn. C. alba)
- †Carya washingtonensis - Manchester Extinct Miocene
- Carya sect. Apocarya – pecans
Carya aquatica (F.Michx.) Nutt. – Bitter pecan or Water Hickory
Carya cordiformis (Wangenh.) K.Koch – Bitternut Hickory
Carya illinoinensis (Wangenh.) K.Koch – Pecan
Carya palmeri W.E. Manning – Mexican Hickory
- Carya aquatica (F.Michx.) Nutt. – Bitter pecan or Water Hickory
- Carya cordiformis (Wangenh.) K.Koch – Bitternut Hickory
- Carya illinoinensis (Wangenh.) K.Koch – Pecan
- Carya palmeri W.E. Manning – Mexican Hickory
# Ecology
Hickory is used as a food plant by the larvae of some Lepidoptera species. These include:
- Luna moth (Actias luna)
- Brown-tail (Euproctis chrysorrhoea)
- Coleophora case-bearers, C. laticornella and C. ostryae
- Regal moths (Citheronia regalis), whose caterpillars are known as hickory horn-devils
- Walnut sphinx (Amorpha juglandis)
- The Bride (nominate subspecies Catocala neogama neogama)
The hickory leaf stem gall phylloxera (Phylloxera caryaecaulis) also uses the hickory tree as a food source. Phylloxeridae are related to aphids and have a similarly complex life cycle. Eggs hatch in early spring and the galls quickly form around the developing insects. Phylloxera galls may damage weakened or stressed hickories, but are generally harmless. Deformed leaves and twigs can rain down from the tree in the spring as squirrels break off infected tissue and eat the galls, possibly for the protein content or because the galls are fleshy and tasty to the squirrels.
The banded hickory borer (Knulliana cincta) is also found on hickories.
# Tryma
Some fruits are borderline and difficult to categorize. Hickory nuts (Carya) and walnuts (Juglans) in the Juglandaceae family grow within an outer husk; these fruits are technically drupes or drupaceous nuts, and thus not true botanical nuts. "Tryma" is a specialized term for such nut-like drupes.
# Uses
Hickory wood is very hard, stiff, dense and shock resistant. There are
woods that are stronger than hickory and woods that are harder, but the combination of strength, toughness, hardness, and stiffness found in hickory wood is not found in any other commercial wood. It is used for tool handles, bows, wheel spokes, carts, drumsticks, lacrosse stick handles, golf club shafts (sometimes still called hickory stick, even though made of steel or graphite), the bottom of skis, walking sticks and for punitive use as a switch (like hazel), and especially as a cane-like hickory stick in schools and use by parents. Paddles are often made from hickory. Baseball bats were formerly made of hickory, but are now more commonly made of ash. Hickory is replacing ash as the wood of choice for Scottish shinty sticks (also known as camans). Hickory was extensively used for the construction of early aircraft.
Hickory is also highly prized for wood-burning stoves, because of its high energy content. Hickory wood is also a preferred type for smoking cured meats. In the Southern United States, hickory is popular for cooking barbecue, as hickory grows abundantly in the region, and adds flavor to the meat. Hickory is sometimes used for wood flooring due to its durability and character.
A bark extract from shagbark hickory is also used in an edible syrup similar to maple syrup, with a slightly bitter, smoky taste.
The nuts of some species are palatable, while others are bitter and only suitable for animal feed. Shagbark and shellbark hickory, along with pecan, are regarded by some as the finest nut trees.
When cultivated for their nuts, clonal (grafted) trees of the same cultivar cannot pollinate each other because of their self-incompatibility. Two or more cultivars must be planted together for successful pollination. Seedlings (grown from hickory nuts) will usually have sufficient genetic variation. | Hickory
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Trees in the genus Carya (Template:Lang-grc "nut") are commonly known as hickory, derived from the Powhatan language of Virginia. The genus includes 17–19 species of deciduous trees with pinnately compound leaves and big nuts. Five or six species are native to China, Indochina, and India (State of Assam), 11 or 12 are from the United States, two to four are from Canada and four are found in Mexico.
Another Asian species, beaked hickory, previously listed as Carya sinensis, is now treated in a separate genus, Annamocarya, as Annamocarya sinensis.
# Species and classification
In the APG system, genus Carya (and the whole Juglandaceae family) has been recently moved to the Fagales order.
- Carya sect. Sinocarya – Asian hickories
Carya dabieshanensis M.C. Liu – Dabie Shan Hickory (may be synonymous with C. cathayensis)
Carya cathayensis Sarg. – Chinese Hickory
Carya hunanensis W.C.Cheng & R.H.Chang – Hunan Hickory
Carya kweichowensis Kuang & A.M.Lu – Guizhou Hickory
Carya poilanei Leroy - Poilane's Hickory
Carya tonkinensis Lecomte – Vietnamese Hickory[3]
- Carya dabieshanensis M.C. Liu – Dabie Shan Hickory (may be synonymous with C. cathayensis)
- Carya cathayensis Sarg. – Chinese Hickory
- Carya hunanensis W.C.Cheng & R.H.Chang – Hunan Hickory
- Carya kweichowensis Kuang & A.M.Lu – Guizhou Hickory
- Carya poilanei Leroy - Poilane's Hickory
- Carya tonkinensis Lecomte – Vietnamese Hickory[3]
- Carya sect. Carya – typical hickories
Carya floridana Sarg. – Scrub Hickory
Carya glabra (Mill.) Sweet – Pignut Hickory, Pignut, Sweet Pignut, Coast Pignut Hickory, Smoothbark Hickory, Swamp Hickory, Broom Hickory
Carya myristiciformis (F.Michx.) Nutt. – Nutmeg Hickory, Swamp Hickory, Bitter Water Hickory
Carya ovalis (Wangenh.) Sarg. – Red Hickory, Spicebark Hickory, Sweet Pignut Hickory (treated as a synonym of C. glabra by Flora N. Amer.)
Carya ovata (Mill.) K.Koch – Shagbark Hickory
Carya ovata var. ovata – Northern Shagbark Hickory
Carya ovata var. australis – Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
Carya laciniosa (Mill.) K.Koch – Shellbark Hickory, Shagbark Hickory, Bigleaf Shagbark Hickory, Kingnut, Big Shellbark, Bottom Shellbark, Thick Shellbark, Western Shellbark
Carya pallida (Ashe) Engl. & Graebn. – Sand Hickory
Carya texana Buckley – Black Hickory
Carya tomentosa (Poir.) Nutt. – Mockernut Hickory (syn. C. alba)
†Carya washingtonensis - Manchester Extinct Miocene
- Carya floridana Sarg. – Scrub Hickory
- Carya glabra (Mill.) Sweet – Pignut Hickory, Pignut, Sweet Pignut, Coast Pignut Hickory, Smoothbark Hickory, Swamp Hickory, Broom Hickory
- Carya myristiciformis (F.Michx.) Nutt. – Nutmeg Hickory, Swamp Hickory, Bitter Water Hickory
- Carya ovalis (Wangenh.) Sarg. – Red Hickory, Spicebark Hickory, Sweet Pignut Hickory (treated as a synonym of C. glabra by Flora N. Amer.)
- Carya ovata (Mill.) K.Koch – Shagbark Hickory
Carya ovata var. ovata – Northern Shagbark Hickory
Carya ovata var. australis – Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
- Carya ovata var. ovata – Northern Shagbark Hickory
- Carya ovata var. australis – Southern Shagbark Hickory, Carolina Hickory (syn. C. carolinae-septentrionalis)
- Carya laciniosa (Mill.) K.Koch – Shellbark Hickory, Shagbark Hickory, Bigleaf Shagbark Hickory, Kingnut, Big Shellbark, Bottom Shellbark, Thick Shellbark, Western Shellbark
- Carya pallida (Ashe) Engl. & Graebn. – Sand Hickory
- Carya texana Buckley – Black Hickory
- Carya tomentosa (Poir.) Nutt. – Mockernut Hickory (syn. C. alba)
- †Carya washingtonensis - Manchester Extinct Miocene
- Carya sect. Apocarya – pecans
Carya aquatica (F.Michx.) Nutt. – Bitter pecan or Water Hickory
Carya cordiformis (Wangenh.) K.Koch – Bitternut Hickory
Carya illinoinensis (Wangenh.) K.Koch – Pecan
Carya palmeri W.E. Manning – Mexican Hickory
- Carya aquatica (F.Michx.) Nutt. – Bitter pecan or Water Hickory
- Carya cordiformis (Wangenh.) K.Koch – Bitternut Hickory
- Carya illinoinensis (Wangenh.) K.Koch – Pecan
- Carya palmeri W.E. Manning – Mexican Hickory
# Ecology
Hickory is used as a food plant by the larvae of some Lepidoptera species. These include:
- Luna moth (Actias luna)
- Brown-tail (Euproctis chrysorrhoea)
- Coleophora case-bearers, C. laticornella and C. ostryae
- Regal moths (Citheronia regalis), whose caterpillars are known as hickory horn-devils
- Walnut sphinx (Amorpha juglandis)
- The Bride (nominate subspecies Catocala neogama neogama)
The hickory leaf stem gall phylloxera (Phylloxera caryaecaulis) also uses the hickory tree as a food source. Phylloxeridae are related to aphids and have a similarly complex life cycle. Eggs hatch in early spring and the galls quickly form around the developing insects. Phylloxera galls may damage weakened or stressed hickories, but are generally harmless. Deformed leaves and twigs can rain down from the tree in the spring as squirrels break off infected tissue and eat the galls, possibly for the protein content or because the galls are fleshy and tasty to the squirrels.
The banded hickory borer (Knulliana cincta) is also found on hickories.
# Tryma
Some fruits are borderline and difficult to categorize. Hickory nuts (Carya) and walnuts (Juglans) in the Juglandaceae family grow within an outer husk; these fruits are technically drupes or drupaceous nuts, and thus not true botanical nuts. "Tryma" is a specialized term for such nut-like drupes.[4][5]
# Uses
Hickory wood is very hard, stiff, dense and shock resistant. There are
woods that are stronger than hickory and woods that are harder, but the combination of strength, toughness, hardness, and stiffness found in hickory wood is not found in any other commercial wood.[6] It is used for tool handles, bows, wheel spokes, carts, drumsticks, lacrosse stick handles, golf club shafts (sometimes still called hickory stick, even though made of steel or graphite), the bottom of skis, walking sticks and for punitive use as a switch (like hazel), and especially as a cane-like hickory stick in schools and use by parents. Paddles are often made from hickory. Baseball bats were formerly made of hickory, but are now more commonly made of ash. Hickory is replacing ash as the wood of choice for Scottish shinty sticks (also known as camans). Hickory was extensively used for the construction of early aircraft.
Hickory is also highly prized for wood-burning stoves, because of its high energy content. Hickory wood is also a preferred type for smoking cured meats. In the Southern United States, hickory is popular for cooking barbecue, as hickory grows abundantly in the region, and adds flavor to the meat. Hickory is sometimes used for wood flooring due to its durability and character.
A bark extract from shagbark hickory is also used in an edible syrup similar to maple syrup, with a slightly bitter, smoky taste.
The nuts of some species are palatable, while others are bitter and only suitable for animal feed. Shagbark and shellbark hickory, along with pecan, are regarded by some as the finest nut trees.
When cultivated for their nuts, clonal (grafted) trees of the same cultivar cannot pollinate each other because of their self-incompatibility. Two or more cultivars must be planted together for successful pollination. Seedlings (grown from hickory nuts) will usually have sufficient genetic variation. | https://www.wikidoc.org/index.php/Hickory | |
ec5d75f6ced2b2af43f6049a3f6b1ee358ceb809 | wikidoc | Hindgut | Hindgut
# Overview
The hindgut (or epigaster) is the posterior (caudal) part of the alimentary canal. It includes the distal third of the transverse colon and the splenic flexure, the descending colon, sigmoid colon, rectum and upper part of the anal canal.
# Blood flow
Arterial supply is by the Inferior mesenteric artery, and venous drainage is to the portal venous system. Lymphatic drainage is to the chyle cistern.
# Autonomic innervation
The hindgut is innervated via the inferior mesenteric plexus. Sympathetic innervation is from the Lumbar splanchnic nerves (L1-L2), parasympathetic innervation is from S2-S4.
# Additional images
- Abdominal part of digestive tube and its attachment to the primitive or common mesentery. Human embryo of six weeks.
- Tail end of human embryo twenty-five to twenty-nine days old. | Hindgut
# Overview
Template:Infobox Embryology
The hindgut (or epigaster) is the posterior (caudal) part of the alimentary canal. It includes the distal third of the transverse colon and the splenic flexure, the descending colon, sigmoid colon, rectum and upper part of the anal canal.
# Blood flow
Arterial supply is by the Inferior mesenteric artery, and venous drainage is to the portal venous system. Lymphatic drainage is to the chyle cistern.
# Autonomic innervation
The hindgut is innervated via the inferior mesenteric plexus. Sympathetic innervation is from the Lumbar splanchnic nerves (L1-L2), parasympathetic innervation is from S2-S4.
# Additional images
- Abdominal part of digestive tube and its attachment to the primitive or common mesentery. Human embryo of six weeks.
- Tail end of human embryo twenty-five to twenty-nine days old. | https://www.wikidoc.org/index.php/Hind-gut | |
0b374c7a6425b36d96b2c6e82811567bbe172c2d | wikidoc | Histone | Histone
In biology, histones are the chief protein components of chromatin. They act as spools around which DNA winds, and they play a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long. For example, each human cell has about 1.8 meters of DNA, but wound on the histones it has about 90 millimeters of chromatin, which, when duplicated and condensed during mitosis, result in about 120 micrometers of chromosomes.
# Classes
There are a total of six classes of histones (H1, H2A, H2B, H3, H4, and H5) organized into two super classes as follows:
- core histones – H2A, H2B, H3 and H4
- linker histones – H1 and H5
Two each of the core histones assemble to form one octameric nucleosome core particle by wrapping 146 base pairs of DNA around the protein spool in 1.65 left-handed super-helical turn. The linker histone H1 binds the nucleosome and the entry and exit sites of the DNA, thus locking the DNA into place and allowing the formation of higher order structure. The most basic such formation is the 10 nm fiber or beads on a string conformation. This involves the wrapping of DNA around nucleosomes with approximately 50 base pairs of DNA spaced between each nucleosome (also referred to as linker DNA). The assembled histones and DNA is called chromatin. Higher order structures include the 30 nm fiber (forming an irregular zigzag) and 100 nm fiber, these being the structures found in normal cells. During mitosis and meiosis, the condensed chromosomes are assembled through interactions between nucleosomes and other regulatory proteins.
The following is a list of human histone proteins:
# Structure
The nucleosome core is formed of two H2A-H2B dimers and a H3-H4 tetramer, forming two nearly symmetrical halves by tertiary structure (C2 symmetry; one macromolecule is the mirror image of the other). The H2A-H2B dimers and H3-H4 tetramer also show pseudodyad symmetry. The 4 'core' histones (H2A, H2B, H3 and H4) are relatively similar in structure and are highly conserved through evolution, all featuring a 'helix turn helix turn helix' motif (which allows the easy dimerisation). They also share the feature of long 'tails' on one end of the amino acid structure - this being the location of post-transcriptional modification (see below).
In all, histones make five types of interactions with DNA:
- Helix-dipoles from alpha-helices in H2B, H3, and H4 cause a net positive charge to accumulate at the point of interaction with negatively charged phosphate groups on DNA.
- Hydrogen bonds between the DNA backbone and the amide group on the main chain of histone proteins.
- Nonpolar interactions between the histone and deoxyribose sugars on DNA.
- Salt links and hydrogen bonds between side chains of basic amino acids (especially lysine and arginine) and phosphate oxygens on DNA.
- Non-specific minor groove insertions of the H3 and H2B N-terminal tails into two minor grooves each on the DNA molecule.
The highly basic nature of histones, aside from facilitating DNA-histone interactions, contributes to the water solubility of histones.
Histones are subject to posttranslational modification by enzymes primarily on their N-terminal tails, but also in their globular domains. Such modifications include methylation, citrullination, acetylation, phosphorylation, Sumoylation, ubiquitination, and ADP-ribosylation. This affects their function of gene regulation (see functions).
In general, genes that are active have less bound histone, while inactive genes are highly associated with histones during interphase. It also appears that the structure of histones has been evolutionarily conserved, as any deleterious mutations would be severely maladaptive.
# Functions
## Compacting DNA strands
Histones act as spools around which DNA winds. This enables the compaction necessary to fit the large genomes of eukaryotes inside cell nuclei: the compacted molecule is 30,000 times shorter than an unpacked molecule.
## Histone modifications in chromatin regulation
Histones undergo posttranslational modifications which alter their interaction with DNA and nuclear proteins. The H3 and H4 histones have long tails protruding from the nucleosome which can be covalently modified at several places. Modifications of the tail include methylation, acetylation, phosphorylation, ubiquitination, sumoylation, citrullination, and ADP-ribosylation. The core of the histones (H2A and H3) can also be modified. Combinations of modifications are thought to constitute a code, the so-called "histone code." Histone modifications act in diverse biological processes such as gene regulation, DNA repair and chromosome condensation (mitosis).
The common nomenclature of histone modifications is as follows:
- The name of the histone (e.g H3)
- The single letter amino acid abbreviation (e.g. K for Lysine) and the amino acid position in the protein
- The type of modification (Me: methyl, P: phosphate, Ac: acetyl, Ub: ubiquitin)
So H3K4me1 denotes the monomethylation of the 4th residue (a lysine) from the start (i.e., the N-terminal) of the H3 protein.
For a detailed example of histone modifications in transcription regulation see RNA polymerase control by chromatin structure and table.
### Influence on gene expression in mammalian cells:
# History
Histones were discovered in 1884 by Albrecht Kossel. The word "histone" dates from the late 19th century and is from the German "Histon", of uncertain origin: perhaps from Greek histanai or from histos. Until the early 1990s, histones were dismissed as merely packing material for nuclear DNA. During the early 1990s, the regulatory functions of histones were discovered.
# Conservation across species
Histones are found in the nuclei of eukaryotic cells, and in certain Archaea, namely Euryarchaea, but not in bacteria. Archaeal histones may well resemble the evolutionary precursors to eukaryotic histones. Histone proteins are among the most highly conserved proteins in eukaryotes, emphasizing their important role in the biology of the nucleus.
Core histones are highly conserved proteins, that is, there are very few differences among the amino acid sequences of the histone proteins of different species. Linker histone usually has more than one form within a species and is also less conserved than the core histones.
There are some variant forms in some of the major classes. They share amino acid sequence homology and core structural similarity to a specific class of major histones but also have their own feature that is distinct from the major histones. These minor histones usually carry out specific functions of the chromatin metabolism. For example, histone H3-like CenpA is a histone only associated with centromere region of the chromosome. Histone H2A variant H2A.Z is associated with the promoters of actively transcribed genes and also involved in the formation of the heterochromatin. Another H2A variant H2A.X binds to the DNA with double strand breaks and marks the region undergoing DNA repair. Histone H3.3 is associated with the body of actively transcribed genes. | Histone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
In biology, histones are the chief protein components of chromatin. They act as spools around which DNA winds, and they play a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long. For example, each human cell has about 1.8 meters of DNA, but wound on the histones it has about 90 millimeters of chromatin, which, when duplicated and condensed during mitosis, result in about 120 micrometers of chromosomes.[1]
# Classes
There are a total of six classes of histones (H1, H2A, H2B, H3, H4, and H5) organized into two super classes as follows:
- core histones – H2A, H2B, H3 and H4
- linker histones – H1 and H5
Two each of the core histones assemble to form one octameric nucleosome core particle by wrapping 146 base pairs of DNA around the protein spool in 1.65 left-handed super-helical turn.[2] The linker histone H1 binds the nucleosome and the entry and exit sites of the DNA, thus locking the DNA into place[3] and allowing the formation of higher order structure. The most basic such formation is the 10 nm fiber or beads on a string conformation. This involves the wrapping of DNA around nucleosomes with approximately 50 base pairs of DNA spaced between each nucleosome (also referred to as linker DNA). The assembled histones and DNA is called chromatin. Higher order structures include the 30 nm fiber (forming an irregular zigzag) and 100 nm fiber, these being the structures found in normal cells. During mitosis and meiosis, the condensed chromosomes are assembled through interactions between nucleosomes and other regulatory proteins.
The following is a list of human histone proteins:
# Structure
The nucleosome core is formed of two H2A-H2B dimers and a H3-H4 tetramer, forming two nearly symmetrical halves by tertiary structure (C2 symmetry; one macromolecule is the mirror image of the other)[2]. The H2A-H2B dimers and H3-H4 tetramer also show pseudodyad symmetry. The 4 'core' histones (H2A, H2B, H3 and H4) are relatively similar in structure and are highly conserved through evolution, all featuring a 'helix turn helix turn helix' motif (which allows the easy dimerisation). They also share the feature of long 'tails' on one end of the amino acid structure - this being the location of post-transcriptional modification (see below).
In all, histones make five types of interactions with DNA:
- Helix-dipoles from alpha-helices in H2B, H3, and H4 cause a net positive charge to accumulate at the point of interaction with negatively charged phosphate groups on DNA.
- Hydrogen bonds between the DNA backbone and the amide group on the main chain of histone proteins.
- Nonpolar interactions between the histone and deoxyribose sugars on DNA.
- Salt links and hydrogen bonds between side chains of basic amino acids (especially lysine and arginine) and phosphate oxygens on DNA.
- Non-specific minor groove insertions of the H3 and H2B N-terminal tails into two minor grooves each on the DNA molecule.
The highly basic nature of histones, aside from facilitating DNA-histone interactions, contributes to the water solubility of histones.[citation needed]
Histones are subject to posttranslational modification by enzymes primarily on their N-terminal tails, but also in their globular domains[citation needed]. Such modifications include methylation, citrullination, acetylation, phosphorylation, Sumoylation, ubiquitination, and ADP-ribosylation. This affects their function of gene regulation (see functions).
In general, genes that are active have less bound histone, while inactive genes are highly associated with histones during interphase[citation needed]. It also appears that the structure of histones has been evolutionarily conserved, as any deleterious mutations would be severely maladaptive.
# Functions
## Compacting DNA strands
Histones act as spools around which DNA winds. This enables the compaction necessary to fit the large genomes of eukaryotes inside cell nuclei: the compacted molecule is 30,000 times shorter than an unpacked molecule.
## Histone modifications in chromatin regulation
Histones undergo posttranslational modifications which alter their interaction with DNA and nuclear proteins. The H3 and H4 histones have long tails protruding from the nucleosome which can be covalently modified at several places. Modifications of the tail include methylation, acetylation, phosphorylation, ubiquitination, sumoylation, citrullination, and ADP-ribosylation. The core of the histones (H2A and H3) can also be modified. Combinations of modifications are thought to constitute a code, the so-called "histone code."[4][5] Histone modifications act in diverse biological processes such as gene regulation, DNA repair and chromosome condensation (mitosis).[citation needed]
The common nomenclature of histone modifications is as follows:
- The name of the histone (e.g H3)
- The single letter amino acid abbreviation (e.g. K for Lysine) and the amino acid position in the protein
- The type of modification (Me: methyl, P: phosphate, Ac: acetyl, Ub: ubiquitin)
So H3K4me1 denotes the monomethylation of the 4th residue (a lysine) from the start (i.e., the N-terminal) of the H3 protein.
For a detailed example of histone modifications in transcription regulation see RNA polymerase control by chromatin structure and table.
### Influence on gene expression in mammalian cells:
# History
Histones were discovered in 1884 by Albrecht Kossel. The word "histone" dates from the late 19th century and is from the German "Histon", of uncertain origin: perhaps from Greek histanai or from histos. Until the early 1990s, histones were dismissed as merely packing material for nuclear DNA. During the early 1990s, the regulatory functions of histones were discovered.[10]
# Conservation across species
Histones are found in the nuclei of eukaryotic cells, and in certain Archaea, namely Euryarchaea, but not in bacteria. Archaeal histones may well resemble the evolutionary precursors to eukaryotic histones. Histone proteins are among the most highly conserved proteins in eukaryotes, emphasizing their important role in the biology of the nucleus.[citation needed]
Core histones are highly conserved proteins, that is, there are very few differences among the amino acid sequences of the histone proteins of different species. Linker histone usually has more than one form within a species and is also less conserved than the core histones.[citation needed]
There are some variant forms in some of the major classes. They share amino acid sequence homology and core structural similarity to a specific class of major histones but also have their own feature that is distinct from the major histones. These minor histones usually carry out specific functions of the chromatin metabolism. For example, histone H3-like CenpA is a histone only associated with centromere region of the chromosome. Histone H2A variant H2A.Z is associated with the promoters of actively transcribed genes and also involved in the formation of the heterochromatin. Another H2A variant H2A.X binds to the DNA with double strand breaks and marks the region undergoing DNA repair. Histone H3.3 is associated with the body of actively transcribed genes.[citation needed] | https://www.wikidoc.org/index.php/Histone | |
5090049d93d5fa44232c4769f71a18e2a47b8088 | wikidoc | Hogging | Hogging
# Background
Hogging refers to the practice of groups of men who target overweight or obese women, typically for sexual encounters. Unlike fat fetishists, men who participate in hogging are not necessarily sexually attracted to obese women's bodies; they aim to take advantage of a female's stereotypical low self esteem or to provide comedy to themselves and their friends by engaging in sexual activities with women who are overweight. In fraternities, hogging refers to a game which is won by the pledge who returns to the fraternity house with the "fattest female who can be found".
# Publications
An unofficial study by Dr. Judith A. Sanders of the California State Polytechnic University Communications Department in Pomona found its use as an offensive slang term to "mack or dance" with overweight women, and Sarah Fenske offered an essay called "Big Game Hunters" in Scoot Over, Skinny : The Fat Nonfiction Anthology detailing various discussions by men regarding the practice. The essay was reprinted in the Cleveland Scene in October of 2003.
This practice was further discussed in an article in volume 27 of the interdisciplinary journal Deviant Behavior by Jeannine Gailey and Ariane Prohaska, "'Knocking off a Fat Girl': an Exploration of Hogging, Male Sexuality, and Neutralizations." In the article, they claim that the practice of hogging is "a part of a larger problem of cultural misogyny." | Hogging
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Background
Hogging refers to the practice of groups of men who target overweight or obese women, typically for sexual encounters. Unlike fat fetishists, men who participate in hogging are not necessarily sexually attracted to obese women's bodies; they aim to take advantage of a female's stereotypical low self esteem or to provide comedy to themselves and their friends by engaging in sexual activities with women who are overweight. In fraternities, hogging refers to a game which is won by the pledge who returns to the fraternity house with the "fattest female who can be found".[1]
# Publications
An unofficial study by Dr. Judith A. Sanders of the California State Polytechnic University Communications Department in Pomona found its use as an offensive slang term to "mack or dance" with overweight women, and Sarah Fenske offered an essay called "Big Game Hunters" in Scoot Over, Skinny : The Fat Nonfiction Anthology detailing various discussions by men regarding the practice. The essay was reprinted in the Cleveland Scene in October of 2003.[2]
This practice was further discussed in an article in volume 27 of the interdisciplinary journal Deviant Behavior by Jeannine Gailey and Ariane Prohaska, "'Knocking off a Fat Girl': an Exploration of Hogging, Male Sexuality, and Neutralizations." In the article, they claim that the practice of hogging is "a part of a larger problem of cultural misogyny."[3] | https://www.wikidoc.org/index.php/Hogging | |
b82156428d48f4d7673f7f5d74a73146f201da53 | wikidoc | Hologic | Hologic
Hologic (Template:Nasdaq) corporation is a leading developer, manufacturer and supplier of premium diagnostic and medical imaging systems dedicated to serving the healthcare needs of women, and a leading developer of state-of-the-art digital imaging technology for general radiography and mammography applications. It's core business units are focused on osteoporosis assessment, mammography and breast biopsy, direct-to-digital x-ray for general radiography applications and mini C-arm imaging for orthopedic applications. Its major brands include Lorad, Fluoroscan, Selenia, Securview, Discovery, Multicare and Directray.
Hologic is a leader in women's healthcare, particularly breast cancer diagnosis.
Hologic is currencly developing tomosynthesis technology for breast cancer diagnosis. Hologic first demonstrated the technology at the Radiological Society of North America in November 2003. It provided patient images and a prototype add-on to its Selenia digital mammography system. Clinical trials for Hologic's tomosynthesis technology began in the summer of 2004.
Hologic was the recipient of Frost and Sullivan's 2004 Technology Leadership of the Year Award in women's healthcare.
# Hologic/Cytyc Merger
On May 20, 2007, Hologic announced a merger (via a cash and stock transaction) with the Cytyc Corporation to create a $10 billion women's healthcare company with over $1 billion in projected annual sales. The new company name will be "Hologic" and Cytyc will be a wholly-owned subsidiary. The combined corporation will deal in products for screening, diagnostics and therapy for breast and cervical cancer, menorrhagia, prenatal health, osteoporosis, endometriosis and permanent contraception. The brands under the combined company include, ThinPrep(R), Lorad(R), NovaSure(R), Suros ATEC(R), Discovery(TM), FullTerm(R), R2(R) and MammoSite(R), and it will have operations in over twenty countries. Patrick Sullivan, of Cytyc will be chairman of the new company, and Jack Cumming, of Hologic, will be Chief Executive Officer. Cytyc shareholders will hold 55% of the firm, and Hologic will own 45%.
# Footnotes | Hologic
Hologic (Template:Nasdaq) corporation is a leading developer, manufacturer and supplier of premium diagnostic and medical imaging systems dedicated to serving the healthcare needs of women, and a leading developer of state-of-the-art digital imaging technology for general radiography and mammography applications. It's core business units are focused on osteoporosis assessment, mammography and breast biopsy, direct-to-digital x-ray for general radiography applications and mini C-arm imaging for orthopedic applications. Its major brands include Lorad, Fluoroscan, Selenia, Securview, Discovery, Multicare and Directray.
Hologic is a leader in women's healthcare, particularly breast cancer diagnosis. [1]
Hologic is currencly developing tomosynthesis technology for breast cancer diagnosis. Hologic first demonstrated the technology at the Radiological Society of North America in November 2003. It provided patient images and a prototype add-on to its Selenia digital mammography system. Clinical trials for Hologic's tomosynthesis technology began in the summer of 2004. [2]
Hologic was the recipient of Frost and Sullivan's 2004 Technology Leadership of the Year Award in women's healthcare. [3]
# Hologic/Cytyc Merger
On May 20, 2007, Hologic announced a merger (via a cash and stock transaction) with the Cytyc Corporation to create a $10 billion women's healthcare company with over $1 billion in projected annual sales.[4] The new company name will be "Hologic" and Cytyc will be a wholly-owned subsidiary. The combined corporation will deal in products for screening, diagnostics and therapy for breast and cervical cancer, menorrhagia, prenatal health, osteoporosis, endometriosis and permanent contraception.[5] The brands under the combined company include, ThinPrep(R), Lorad(R), NovaSure(R), Suros ATEC(R), Discovery(TM), FullTerm(R), R2(R) and MammoSite(R), and it will have operations in over twenty countries.[6] Patrick Sullivan, of Cytyc will be chairman of the new company, and Jack Cumming, of Hologic, will be Chief Executive Officer.[7] Cytyc shareholders will hold 55% of the firm, and Hologic will own 45%.
# Footnotes
- ↑ http://www.forbes.com/markets/2007/05/21/hologic-cytyc-cancer-markets-equity-cx_er_0521markets03.html
- ↑ http://www.hoise.com/vmw/04/articles/vmw/LV-VM-12-04-37.html
- ↑ http://www.hoise.com/vmw/04/articles/vmw/LV-VM-12-04-37.html
- ↑ http://www.forbes.com/feeds/ap/2007/05/21/ap3740939.html
- ↑ http://www.clpmag.com/clprime/2007-05-30_01.asp
- ↑ http://news.corporate.findlaw.com/prnewswire/20070520/20may20071503.html
- ↑ http://news.corporate.findlaw.com/prnewswire/20070520/20may20071503.html
# External Links
- http://www.hologic.com
- http://www.hologic.com/ah/seediff.htm
- http://www.hologic.com/wh/faqs.htm
- http://www.hologic.com/ir/faqs.htm
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Hologic | |
3b0214b01f72dc1fa38fc9ec4817a288d3c18d10 | wikidoc | Hoptree | Hoptree
The Hoptree (Ptelea trifoliata, Rutaceae) is a deciduous shrub or small tree 6-8 m tall with a broad crown. It is native to North America, from southern Ontario, Canada southeast to Florida, USA, west to southern California and south to Oaxaca in southern Mexico.
# Taxonomy
While most often treated as a single species with several varieties, some botanists treat the Hoptree as a group of four or more closely related species:
- Eastern Hoptree P. trifoliata var. trifoliata (P. trifoliata, sensu stricto)
- Florida Hoptree P. trifoliata var. baldwinii (P. baldwinii)
- Western Hoptree P. trifoliata var. crenulata (P. crenulata)
- Narrowleaf Hoptree P. trifoliata var. angustifolia (P. angustifolia, P. lutescens)
Ptelea, of Greek derivation, is the classical name of the elm tree, which was transferred by Linnaeus to this genus, because of the resemblance of its fruit to that of the elm. Trifoliata refers to the three-parted compound leaf.
# Description
A small tree but often a shrub of a few spreading stems. It makes part of the undergrowth of the Mississippi river valley, and is found most frequently on rocky slopes. Has thick fleshy roots, flourishes in rich, rather moist soil. Its juices are acrid and bitter and the bark possesses tonic properties.
The twigs are slender to moderately stout, brown with deep U-shaped leaf scars, and with short, light brown, fuzzy buds. The leaves are alternate, 5-18 cm long, palmately compound with three (rarely five) leaflets, each leaflet 1-10 cm long, sparsely serrated or entire, shiny dark green above, paler below. The western and southwestern forms have smaller leaves (5-11 cm) than the eastern forms (10-18 cm), an adaptation to the drier climates there.
The flowers are small, 1-2 cm across, with 4-5 narrow, greenish white petals, produced in terminal, branched clusters in spring: some find the odor unpleasant but to others trifoliata has a delicious scent. The fruit is a round wafer-like papery samara, 2-2.5 cm across, light brown, maturing in summer. Seed vessel has a thin wing and is held on tree until high winds during early winter.
The bark is reddish brown to gray brown, short horizontal lenticels, warty corky ridges, becoming slightly scaly, unpleasant odor and bitter taste. It has several Native American uses as a herbal medicine for different ailments.
- Bark: Dark reddish brown, smooth. Branchlets dark reddish brown, shining, covered with small excrescences. Bitter and ill-scented.
- Wood: Yellow brown; heavy, hard, close-grained, satiny. Sp. gr., 0.8319; weight of cu. ft., 51.84 lbs.
- Winter buds: Small, depressed, round, pale, covered with silvery hairs.
- Leaves: Alternate, compound, three-parted, dotted with oil glands. Leaflets sessile, ovate or oblong, three to five inches long, by two to three broad, pointed at base, entire or serrate, gradially pointed at apex. Feather-veined, midrib and primary veins prominent. They come out of the bud conduplicate, very downy, when full grown are dark green, shining above, paler green beneath. In autumn they turn a rusty yellow. Petioles stout, two and a half to three inches long, base enlarged. Stipules wanting.
- Flowers: May, June. Polygamo-monoecious, greenish white. Fertile and sterile flowers produced together in terminal, spreading, compound cymes; the sterile being usually fewer, and falling after the anther cells mature. Pedicels downy.
- Calyx: Four or five-parted, downy, imbricate in the bud.
- Corolla: Petals four or five, white, downy, spreading, hypogynous, imbricate in bud.
- Stamens: Five, alternate with the petals, hypogynous, the psitillate flowers with rudimentary anters; filaments awl-shaped, more or less hairy; anthers ovate or cordate, two-celled, cells opening longitudinally.
- Pistils: Ovary superior, hairy, abortive in the staminate flowers, two to three-celled; style short; stigma two to three-lobed; ovules two in each cell.
- Fruit: Samara, orbicular, surrounded by a broad, many-veined reticulate membranous ring, two-seeded. Ripens in October and hangs in clusters until midwinter. | Hoptree
The Hoptree (Ptelea trifoliata, Rutaceae) is a deciduous shrub or small tree 6-8 m tall with a broad crown. It is native to North America, from southern Ontario, Canada southeast to Florida, USA, west to southern California and south to Oaxaca in southern Mexico.
# Taxonomy
While most often treated as a single species with several varieties, some botanists treat the Hoptree as a group of four or more closely related species:
- Eastern Hoptree P. trifoliata var. trifoliata (P. trifoliata, sensu stricto)
- Florida Hoptree P. trifoliata var. baldwinii (P. baldwinii)
- Western Hoptree P. trifoliata var. crenulata (P. crenulata)
- Narrowleaf Hoptree P. trifoliata var. angustifolia (P. angustifolia, P. lutescens)
Ptelea, of Greek derivation, is the classical name of the elm tree, which was transferred by Linnaeus to this genus, because of the resemblance of its fruit to that of the elm. Trifoliata refers to the three-parted compound leaf.[1]
# Description
A small tree but often a shrub of a few spreading stems. It makes part of the undergrowth of the Mississippi river valley, and is found most frequently on rocky slopes. Has thick fleshy roots, flourishes in rich, rather moist soil. Its juices are acrid and bitter and the bark possesses tonic properties.[1]
The twigs are slender to moderately stout, brown with deep U-shaped leaf scars, and with short, light brown, fuzzy buds. The leaves are alternate, 5-18 cm long, palmately compound with three (rarely five) leaflets, each leaflet 1-10 cm long, sparsely serrated or entire, shiny dark green above, paler below. The western and southwestern forms have smaller leaves (5-11 cm) than the eastern forms (10-18 cm), an adaptation to the drier climates there.
The flowers are small, 1-2 cm across, with 4-5 narrow, greenish white petals, produced in terminal, branched clusters in spring: some find the odor unpleasant but to others trifoliata has a delicious scent. The fruit is a round wafer-like papery samara, 2-2.5 cm across, light brown, maturing in summer. Seed vessel has a thin wing and is held on tree until high winds during early winter.[1]
The bark is reddish brown to gray brown, short horizontal lenticels, warty corky ridges, becoming slightly scaly, unpleasant odor and bitter taste. It has several Native American uses as a herbal medicine for different ailments.
- Bark: Dark reddish brown, smooth. Branchlets dark reddish brown, shining, covered with small excrescences. Bitter and ill-scented.
- Wood: Yellow brown; heavy, hard, close-grained, satiny. Sp. gr., 0.8319; weight of cu. ft., 51.84 lbs.
- Winter buds: Small, depressed, round, pale, covered with silvery hairs.
- Leaves: Alternate, compound, three-parted, dotted with oil glands. Leaflets sessile, ovate or oblong, three to five inches long, by two to three broad, pointed at base, entire or serrate, gradially pointed at apex. Feather-veined, midrib and primary veins prominent. They come out of the bud conduplicate, very downy, when full grown are dark green, shining above, paler green beneath. In autumn they turn a rusty yellow. Petioles stout, two and a half to three inches long, base enlarged. Stipules wanting.
- Flowers: May, June. Polygamo-monoecious, greenish white. Fertile and sterile flowers produced together in terminal, spreading, compound cymes; the sterile being usually fewer, and falling after the anther cells mature. Pedicels downy.
- Calyx: Four or five-parted, downy, imbricate in the bud.
- Corolla: Petals four or five, white, downy, spreading, hypogynous, imbricate in bud.
- Stamens: Five, alternate with the petals, hypogynous, the psitillate flowers with rudimentary anters; filaments awl-shaped, more or less hairy; anthers ovate or cordate, two-celled, cells opening longitudinally.
- Pistils: Ovary superior, hairy, abortive in the staminate flowers, two to three-celled; style short; stigma two to three-lobed; ovules two in each cell.
- Fruit: Samara, orbicular, surrounded by a broad, many-veined reticulate membranous ring, two-seeded. Ripens in October and hangs in clusters until midwinter.[1]
# External links
- NCRS: USDA Plants Profile: Ptelea trifoliata | https://www.wikidoc.org/index.php/Hoptree | |
114aea07a82781d2d001d2e9d054ab333c78362d | wikidoc | Hormone | Hormone
A hormone (from Greek όρμή - "to set in motion") is a chemical messenger that carries a signal from one cell (or group of cells) to another. All multicellular organisms produce hormones (including plants).
The function of hormones is to carry information to the target cells; the action of hormones is determined by the pattern of secretion and response of the receiving tissue - the signal transduction response.
The best-known animal hormones are those produced by endocrine glands of vertebrate animals, but hormones are produced by nearly every organ system and tissue type in a multicellular organism.
Endocrine hormone molecules are secreted (released) directly into the bloodstream, while exocrine hormones (or ectohormones) are secreted directly into a duct, and from the duct they either flow into the bloodstream or they flow from cell to cell by diffusion in a process known as paracrine signalling.
# Hierarchical nature of hormonal control
# Hormone signaling
Hormonal signaling across this hierarchy involves the following:
- Biosynthesis of a particular hormone in a particular tissue.
- Storage and secretion of the hormone.
- Transport of the hormone to the target cell(s).
- Recognition of the hormone by an associated cell membrane or intracellular receptor protein.
- Relay and amplification of the received hormonal signal via a signal transduction process. This then leads to a cellular response. The reaction of the target cells may then be recognized by the original hormone-producing cells, leading to a down-regulation in hormone production. This is an example of a homeostatic negative feedback loop.
- Degradation of the hormone.
As can be inferred from the hierarchical diagram, hormone biosynthetic cells are typically of a specialized cell type, residing within a particular endocrine gland (e.g. the thyroid gland, ovaries or testes). Hormones may exit their cell of origin via exocytosis or another means of membrane transport. However, the hierarchical model is an over simplification of the hormonal signaling process. Typically cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues, as is the case for insulin, which triggers a diverse range of systemic physiological effects. Different tissue types may also respond differently to the same hormonal signal. Because of this, hormonal signaling is elaborate and hard to dissect.
# Interactions with receptors
Most hormones initiate a cellular response by initially combining with either a specific intracellular or cell membrane associated receptor protein. A cell may have several different receptors that recognize the same hormone and activate different signal transduction pathways, or alternatively different hormones and their receptors may invoke the same biochemical pathway.
For many hormones, including most protein hormones, the receptor is membrane associated and embedded in the plasma membrane at the surface of the cell. The interaction of hormone and receptor typically triggers a cascade of secondary effects within the cytoplasm of the cell, often involving phosphorylation or dephosphorylation of various other cytoplasmic proteins, changes in ion channel permeability, or increased concentrations of intracellular molecules that may act as secondary messengers (e.g. cyclic AMP). Some protein hormones also interact with intracellular receptors located in the cytoplasm or nucleus by an intracrine mechanism.
For hormones such as steroid or thyroid hormones, their receptors are located intracellularly within the cytoplasm of their target cell. In order to bind their receptors these hormones must cross the cell membrane. The combined hormone-receptor complex then moves across the nuclear membrane into the nucleus of the cell, where it binds to specific DNA sequences, effectively amplifying or suppressing the action of certain genes, and affecting protein synthesis. However, it has been shown that not all steroid receptors are located intracellularly, some are plasma membrane associated.
An important consideration, dictating the level at which cellular signal transduction pathways are activated in response to a hormonal signal is the effective concentration of hormone-receptor complexes that are formed. Hormone-receptor complex concentrations are effectively determined by three factors:
- The number of hormone molecules available for complex formation
- The number of receptor molecules available for complex formation and
- The binding affinity between hormone and receptor.
The number of hormone molecules available for complex formation is usually the key factor in determining the level at which signal transduction pathways are activated. The number of hormone molecules available being determined by the concentration of circulating hormone, which is in turn influenced by the level and rate at which they are secreted by biosynthetic cells. The number of receptors at the cell surface of the receiving cell can also be varied as can the affinity between the hormone and its receptor.
# Physiology of hormones
Most cells are capable of producing one or more molecules, which act as signalling molecules to other cells, altering their growth, function, or metabolism. The classical hormones produced by endocrine glands mentioned so far in this article are cellular products, specialized to serve as regulators at the overall organism level. However they may also exert their effects solely within the tissue in which they are produced and originally released.
The rate of hormone biosynthesis and secretion is often regulated by a homeostatic negative feedback control mechanism. Such a mechanism depends on factors which influence the metabolism and excretion of hormones. Thus, higher hormome concentration alone can not trigger the negative feedback mechanism. Negative feedback must be triggered by overproduction of an "effect" of the hormone.
Hormone secretion can be stimulated and inhibited by:
- Other hormones (stimulating- or releasing-hormones)
- Plasma concentrations of ions or nutrients, as well as binding globulins
- Neurons and mental activity
- Environmental changes, e.g., of light or temperature
One special group of hormones is the tropic hormones that stimulate the hormone production of other endocrine glands. For example, thyroid-stimulating hormone (TSH) causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones.
A recently-identified class of hormones is that of the "hunger hormones" - ghrelin, orexin and PYY 3-36 - and "satiety hormones" - e.g., leptin, obestatin, nesfatin-1.
In order to release active hormones quickly into the circulation, hormone biosynthetic cells may produce and store biologically inactive hormones in the form of pre- or prohormones. These can then be quickly converted into their active hormone form in response to a particular stimulus.
# Hormone effects
Hormone effects vary widely, but can include:
- stimulation or inhibition of growth,
- induction or suppression of apoptosis (programmed cell death)
- activation or inhibition of the immune system
- regulating metabolism
- preparation for a new activity (e.g., fighting, fleeing, mating)
- preparation for a new phase of life (e.g., puberty, caring for offspring, menopause)
- controlling the reproductive cycle
In many cases, one hormone may regulate the production and release of other hormones
Many of the responses to hormone signals can be described as serving to regulate metabolic activity of an organ or tissue.
# Chemical classes of hormones
Vertebrate hormones fall into three chemical classes:
- Amine-derived hormones are derivatives of the amino acids tyrosine and tryptophan. Examples are catecholamines and thyroxine.
- Peptide hormones consist of chains of amino acids. Examples of small peptide hormones are TRH and vasopressin. Peptides composed of scores or hundreds of amino acids are referred to as proteins. Examples of protein hormones include insulin and growth hormone. More complex protein hormones bear carbohydrate side chains and are called glycoprotein hormones. Luteinizing hormone, follicle-stimulating hormone and thyroid-stimulating hormone are glycoprotein hormones.
- Lipid and phospholipid-derived hormones derive from lipids such as linoleic acid and arachidonic acid and phospholipids. The main classes are the steroid hormones that derive from cholesterol and the eicosanoids. Examples of steroid hormones are testosterone and cortisol. Sterol hormones such as calcitriol are a homologous system. The adrenal cortex and the gonads are primary sources of steroid hormones. Examples of eicosanoids are the widely studied prostaglandins.
# Pharmacology
Many hormones and their analogues are used as medication. The most commonly-prescribed hormones are estrogens and progestagens (as methods of hormonal contraception and as HRT), thyroxine (as levothyroxine, for hypothyroidism) and steroids (for autoimmune diseases and several respiratory disorders). Insulin is used by many diabetics. Local preparations for use in otolaryngology often contain pharmacologic equivalents of adrenaline, while steroid and vitamin D creams are used extensively in dermatological practice.
A "pharmacologic dose" of a hormone is a medical usage referring to an amount of a hormone far greater than naturally occurs in a healthy body. The effects of pharmacologic doses of hormones may be different from responses to naturally-occurring amounts and may be therapeutically useful. An example is the ability of pharmacologic doses of glucocorticoid to suppress inflammation.
# Important human hormones
Spelling is not uniform for many hormones. Current North American and international usage is estrogen, gonadotropin, while British usage retains the Greek diphthong in oestrogen and the unvoiced aspirant h in gonadotrophin. | Hormone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
A hormone (from Greek όρμή - "to set in motion") is a chemical messenger that carries a signal from one cell (or group of cells) to another. All multicellular organisms produce hormones (including plants).
The function of hormones is to carry information to the target cells; the action of hormones is determined by the pattern of secretion and response of the receiving tissue - the signal transduction response.
The best-known animal hormones are those produced by endocrine glands of vertebrate animals, but hormones are produced by nearly every organ system and tissue type in a multicellular organism.
Endocrine hormone molecules are secreted (released) directly into the bloodstream, while exocrine hormones (or ectohormones) are secreted directly into a duct, and from the duct they either flow into the bloodstream or they flow from cell to cell by diffusion in a process known as paracrine signalling.
# Hierarchical nature of hormonal control
# Hormone signaling
Hormonal signaling across this hierarchy involves the following:
- Biosynthesis of a particular hormone in a particular tissue.
- Storage and secretion of the hormone.
- Transport of the hormone to the target cell(s).
- Recognition of the hormone by an associated cell membrane or intracellular receptor protein.
- Relay and amplification of the received hormonal signal via a signal transduction process. This then leads to a cellular response. The reaction of the target cells may then be recognized by the original hormone-producing cells, leading to a down-regulation in hormone production. This is an example of a homeostatic negative feedback loop.
- Degradation of the hormone.
As can be inferred from the hierarchical diagram, hormone biosynthetic cells are typically of a specialized cell type, residing within a particular endocrine gland (e.g. the thyroid gland, ovaries or testes). Hormones may exit their cell of origin via exocytosis or another means of membrane transport. However, the hierarchical model is an over simplification of the hormonal signaling process. Typically cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues, as is the case for insulin, which triggers a diverse range of systemic physiological effects. Different tissue types may also respond differently to the same hormonal signal. Because of this, hormonal signaling is elaborate and hard to dissect.
# Interactions with receptors
Most hormones initiate a cellular response by initially combining with either a specific intracellular or cell membrane associated receptor protein. A cell may have several different receptors that recognize the same hormone and activate different signal transduction pathways, or alternatively different hormones and their receptors may invoke the same biochemical pathway.
For many hormones, including most protein hormones, the receptor is membrane associated and embedded in the plasma membrane at the surface of the cell. The interaction of hormone and receptor typically triggers a cascade of secondary effects within the cytoplasm of the cell, often involving phosphorylation or dephosphorylation of various other cytoplasmic proteins, changes in ion channel permeability, or increased concentrations of intracellular molecules that may act as secondary messengers (e.g. cyclic AMP). Some protein hormones also interact with intracellular receptors located in the cytoplasm or nucleus by an intracrine mechanism.
For hormones such as steroid or thyroid hormones, their receptors are located intracellularly within the cytoplasm of their target cell. In order to bind their receptors these hormones must cross the cell membrane. The combined hormone-receptor complex then moves across the nuclear membrane into the nucleus of the cell, where it binds to specific DNA sequences, effectively amplifying or suppressing the action of certain genes, and affecting protein synthesis.[1] However, it has been shown that not all steroid receptors are located intracellularly, some are plasma membrane associated.[2]
An important consideration, dictating the level at which cellular signal transduction pathways are activated in response to a hormonal signal is the effective concentration of hormone-receptor complexes that are formed. Hormone-receptor complex concentrations are effectively determined by three factors:
- The number of hormone molecules available for complex formation
- The number of receptor molecules available for complex formation and
- The binding affinity between hormone and receptor.
The number of hormone molecules available for complex formation is usually the key factor in determining the level at which signal transduction pathways are activated. The number of hormone molecules available being determined by the concentration of circulating hormone, which is in turn influenced by the level and rate at which they are secreted by biosynthetic cells. The number of receptors at the cell surface of the receiving cell can also be varied as can the affinity between the hormone and its receptor.
# Physiology of hormones
Most cells are capable of producing one or more molecules, which act as signalling molecules to other cells, altering their growth, function, or metabolism. The classical hormones produced by endocrine glands mentioned so far in this article are cellular products, specialized to serve as regulators at the overall organism level. However they may also exert their effects solely within the tissue in which they are produced and originally released.
The rate of hormone biosynthesis and secretion is often regulated by a homeostatic negative feedback control mechanism. Such a mechanism depends on factors which influence the metabolism and excretion of hormones. Thus, higher hormome concentration alone can not trigger the negative feedback mechanism. Negative feedback must be triggered by overproduction of an "effect" of the hormone.
Hormone secretion can be stimulated and inhibited by:
- Other hormones (stimulating- or releasing-hormones)
- Plasma concentrations of ions or nutrients, as well as binding globulins
- Neurons and mental activity
- Environmental changes, e.g., of light or temperature
One special group of hormones is the tropic hormones that stimulate the hormone production of other endocrine glands. For example, thyroid-stimulating hormone (TSH) causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones.
A recently-identified class of hormones is that of the "hunger hormones" - ghrelin, orexin and PYY 3-36 - and "satiety hormones" - e.g., leptin, obestatin, nesfatin-1.
In order to release active hormones quickly into the circulation, hormone biosynthetic cells may produce and store biologically inactive hormones in the form of pre- or prohormones. These can then be quickly converted into their active hormone form in response to a particular stimulus.
# Hormone effects
Hormone effects vary widely, but can include:
- stimulation or inhibition of growth,
- induction or suppression of apoptosis (programmed cell death)
- activation or inhibition of the immune system
- regulating metabolism
- preparation for a new activity (e.g., fighting, fleeing, mating)
- preparation for a new phase of life (e.g., puberty, caring for offspring, menopause)
- controlling the reproductive cycle
In many cases, one hormone may regulate the production and release of other hormones
Many of the responses to hormone signals can be described as serving to regulate metabolic activity of an organ or tissue.
# Chemical classes of hormones
Vertebrate hormones fall into three chemical classes:
- Amine-derived hormones are derivatives of the amino acids tyrosine and tryptophan. Examples are catecholamines and thyroxine.
- Peptide hormones consist of chains of amino acids. Examples of small peptide hormones are TRH and vasopressin. Peptides composed of scores or hundreds of amino acids are referred to as proteins. Examples of protein hormones include insulin and growth hormone. More complex protein hormones bear carbohydrate side chains and are called glycoprotein hormones. Luteinizing hormone, follicle-stimulating hormone and thyroid-stimulating hormone are glycoprotein hormones.
- Lipid and phospholipid-derived hormones derive from lipids such as linoleic acid and arachidonic acid and phospholipids. The main classes are the steroid hormones that derive from cholesterol and the eicosanoids. Examples of steroid hormones are testosterone and cortisol. Sterol hormones such as calcitriol are a homologous system. The adrenal cortex and the gonads are primary sources of steroid hormones. Examples of eicosanoids are the widely studied prostaglandins.
# Pharmacology
Many hormones and their analogues are used as medication. The most commonly-prescribed hormones are estrogens and progestagens (as methods of hormonal contraception and as HRT), thyroxine (as levothyroxine, for hypothyroidism) and steroids (for autoimmune diseases and several respiratory disorders). Insulin is used by many diabetics. Local preparations for use in otolaryngology often contain pharmacologic equivalents of adrenaline, while steroid and vitamin D creams are used extensively in dermatological practice.
A "pharmacologic dose" of a hormone is a medical usage referring to an amount of a hormone far greater than naturally occurs in a healthy body. The effects of pharmacologic doses of hormones may be different from responses to naturally-occurring amounts and may be therapeutically useful. An example is the ability of pharmacologic doses of glucocorticoid to suppress inflammation.
# Important human hormones
Spelling is not uniform for many hormones. Current North American and international usage is estrogen, gonadotropin, while British usage retains the Greek diphthong in oestrogen and the unvoiced aspirant h in gonadotrophin. | https://www.wikidoc.org/index.php/Hormonal | |
3eea1cc495933d9a904e70ca3d1f16a95251b707 | wikidoc | Hot tub | Hot tub
A hot tub is a large home-made or manufactured tub or small pool full of heated water and used for soaking, relaxation, massage, or hydrotherapy. In most cases, they have jets for massage purposes. Hot tubs are usually located outdoors, and are often sheltered for protection from the elements, as well as for privacy.
There are two different styles of hot tubs:
- Simple wooden-staved soaking tubs
- One piece plastic tubs (usually referred to as "spas")
Hot tubs are usually heated using an electric or natural gas heater, though there are also submersible wood-fired heaters, as well as solar hot water systems. Hot tubs are also found at natural hot springs; in this case, the water may be dangerously hot and must be combined with cool water for a safe soaking temperature.
Water sanitization is very important in hot tubs, as many organisms thrive in a warm, wet environment. Maintaining the hot tub water chemistry is also necessary for proper sanitization and to prevent damage to the hot tub.
Of the 130-odd manufacturers in North America in 2005, the top twenty each produced more than 7,000 spas annually. China is fastly becoming the largest supplier of Hot Tubs
# Wooden tubs
This style of hot tub is constructed with wooden staves and steel bands, very much like a very large barrel. The staves are usually made of redwood, cedar, or teak, with most historic tubs made of redwood. Wooden hot tubs are often quite deep, 36"-48", and are inset within a wooden deck for ease of entry. Inside the tub, wooden bench seating is common, forming a ring around the inner circumference of the tub. Katie Bianchi and Celia DeJohn were the first Americans to invent the hot tub in 1901.
# One Piece Hot Tubs
One piece spas, also known as unibody spas, are formed as one piece with shapes that provide a variety of seating arrangements within the tub. Each integral seat is often equipped with one or more water jets that allows water to be directed at parts of the body. The water flow may be aerated for additional effect, and some or all of the jets may also automatically move or rotate, providing a massage-like effect.
Although wooden tubs were the most common type of hot tub in the 1970s, one-piece hot tubs now dominate the market as they are less expensive to manufacture, easier to install, and more energy efficient. In America, these kinds of tubs are also referred to as Jacuzzi or Whirlpool tubs, though both are brand names.
One piece spas are usually shallower than wooden tubs, usually being 32" to 36" in height to fit through doors and narrow hallways. Cranes are occasionally used to place one piece spas in a backyard or other location that does not have adequate clearance for carrying the tub.
Spas usually have between one and four water pumps, with one circulation pump serving the heating and filtration water loop and the other(s) driving the hydrotherapy jets. Sophisticated computer controls are now common and many tubs now are equipped with extensive lighting, sound systems, and even flat panel televisions with DVD players.
# Construction of a one-piece spa
The spa shell is the exterior of the tub, and is composed of a surface and an understructure that are bonded together during the manufacturing process. The surface is the source of the color, look and feel of the spa, so it should resist deterioration due to the sun, spa chemicals, or normal wear and tear. Some high-end shells have special coatings to make them more stain resistant or have anti-bacterial ingredients molded into the shell material.
There two primary methods used for manufacturing one piece spa shells:
- vacuum forming of an acrylic base by placing the sheet over a mold and heating with an overhead heater while pulling a vacuum on the mold
- rotational molding: involves placing polyethylene powder in an aluminum mold which is then heated and spun in a large oven so that the plastic melts and takes the form of the mold.
The understructure of the shell provides the strength needed to support hundreds of gallons of water and the weight of the bathers (the cabinet is not normally part of the weight-bearing structure). The substructure is generally made of FRP (commonly called fiberglass), though some companies use ABS or other plastics. Some manufacturers build a self-supporting shell, while others use secondary supports of wood or metal under the seats or in high-stress areas to reduce the amount of FRP required. Some companies use a perimeter frame of wood or metal to support the rim.
The plumbing of the spa consists of several distinct systems:
- A pressure system delivering water to the jets
- A suction system returning water to the pumps.
- A filtration system - the plumbing has to incorporate a filter system to help clean the water. Some models use a separate small 24/7 filter pump while others use programmed settings of the main pumps.
- Induced air - The jets may use a venturi effect to incorporate air into the water stream for a lighter massage effect; this requires another set of hoses.
- Some models use an air blower to force air through a separate set of jets for a different "bubbly" massage effect; this is a separate system from the induced air.
- An ozone system - ozonation is a common adjunct to water maintenance, and if installed will have its own set of hoses and fittings.
The spa cabinet is the skirting around the hot tub, and serves as both an enclosure for the plumbing and a decorative wrap. For many years, spa cabinetry was made of wood, most commonly redwood or cedar, and this is still a popular choice. Wood cabinets require regular maintenance, though, especially in climates where they are exposed to severe weathering. Synthetic materials are increasingly popular because they are seen as requiring relatively little maintenance to keep their appearance.
# Energy efficiency
Effective insulation greatly improves the energy efficiency of a spa. There are several different styles of spa insulation: some manufacturers fill the entire cabinet with foam, while others insulate the underside of the shell, the inside of the cabinet, or both. Not surprisingly, many manufacturers advertise the superiority of their approach to insulation, but few independent side-by-side comparisons are available. The spa pump and hot tub heater represent most of the power consumption in a hot tub and vary in use of power depending on their size.
Energy efficiency of the tubs has been studied by the Pacific Gas and Electric Company. The industry has responded to the study.
After this study, both the California Energy Commission and National Resources Canada have taken an interest in the energy efficiency of portable spas (late 2006).
California's portable electric spa listing include R Values of thermal insulation, and standby watts.
# Alternative Designs
Metal stock tanks have also been used as a cheap alternative for a hot tub, though the lack of insulation makes heating difficult. There are also hot tubs that use firm insulation coated in vinyl to hold in water, but these must be short due to the weight of water and the relatively low tensional strength of insulation and vinyl.
# Sanitation and chemistry
Maintaining hot tub water sanitation and chemistry is necessary to prevent the spread of disease as well as damage to the tub. In addition to the use of a pump and micrometre-range particulate filter, bromine, chlorine or mineral sanitizers are almost always used as a primary sanitizer, and often supplemented with an ozone generator, UV sterilization, and/or silver and copper ion generator (also known as a "spa ionizer"). If only chlorine is used, a primary algaecide such as polyquat may be additionally needed, since these microbes are more resistant to chlorine than are most bacteria.
To periodically remove any stubborn microorganisms, or in the event of poor water sanitation, "shocking" the hot tub is recommended. This can be done with either potassium monopersulfate (usually referred to as "non-chlorine shock"), or a relatively large dose of granulated chlorine. The hot tub should not be used for a period of time after starting the shock treatment, typically 15 minutes for potassium monopersulfate and 8 hours for chlorine.
Maintaining the water chemistry involves keeping the pH, total alkalinity, and calcium hardness within acceptable margins. Most important are the pH and total alkalinity: if not maintained, the primary sanitizer (chlorine, bromine or mineral sanitizer) will not function effectively. Also, severe problems with the water chemistry may cause metal parts of the tub's plumbing to corrode, damaging or destroying them. The Langlier Saturation Index is important to determine and maintain properly, so that calcium and magnesium deposits do not form in the water heater
Poor hot tub sanitation, whether by improper design or failure of the sanitation system, can result in disease transmission and litigation. It is recommended to have multiple sanitation systems to prevent system failure if one sanitation subsystem fails.
# Commonly used terms
Hot tub - name originally given to the earliest tubs that were round, made of wood, and located outdoors; now is commonly used interchangeably with the phrases 'home spa' and 'portable spa'.
Home spa - generally made with a plastic shell; surrounding cabinet may be made of wood or synthetic materials; can be used to describe an above ground, in-ground, indoor or outdoor spa.
Portable hot tub/portable home spa - name for any hot tub/home spa that is pre-assembled and sits above ground; actual size and features of a portable hot tub vary widely, from small portable hot tubs that weigh only a few hundred pounds and plug into a household outlet to large tubs that weigh several thousand pounds and require specific installation methods and electrical wiring.
# Stereo systems
Some hot tub models have integrated sound systems. These sound systems are typically made of marine grade components that can withstand the humid environments associated with spas. | Hot tub
A hot tub is a large home-made or manufactured tub or small pool full of heated water and used for soaking, relaxation, massage, or hydrotherapy. In most cases, they have jets for massage purposes. Hot tubs are usually located outdoors, and are often sheltered for protection from the elements, as well as for privacy.
There are two different styles of hot tubs:
- Simple wooden-staved soaking tubs
- One piece plastic tubs (usually referred to as "spas")
Hot tubs are usually heated using an electric or natural gas heater, though there are also submersible wood-fired heaters, as well as solar hot water systems. Hot tubs are also found at natural hot springs; in this case, the water may be dangerously hot and must be combined with cool water for a safe soaking temperature.
Water sanitization is very important in hot tubs, as many organisms thrive in a warm, wet environment. Maintaining the hot tub water chemistry is also necessary for proper sanitization and to prevent damage to the hot tub.
Of the 130-odd manufacturers in North America in 2005, the top twenty each produced more than 7,000 spas annually.[citation needed] China is fastly becoming the largest supplier of Hot Tubs
# Wooden tubs
This style of hot tub is constructed with wooden staves and steel bands, very much like a very large barrel. The staves are usually made of redwood, cedar, or teak, with most historic tubs made of redwood. Wooden hot tubs are often quite deep, 36"-48", and are inset within a wooden deck for ease of entry. Inside the tub, wooden bench seating is common, forming a ring around the inner circumference of the tub. Katie Bianchi and Celia DeJohn were the first Americans to invent the hot tub in 1901.
# One Piece Hot Tubs
One piece spas, also known as unibody spas, are formed as one piece with shapes that provide a variety of seating arrangements within the tub. Each integral seat is often equipped with one or more water jets that allows water to be directed at parts of the body. The water flow may be aerated for additional effect, and some or all of the jets may also automatically move or rotate, providing a massage-like effect.
Although wooden tubs were the most common type of hot tub in the 1970s, one-piece hot tubs now dominate the market as they are less expensive to manufacture, easier to install, and more energy efficient. In America, these kinds of tubs are also referred to as Jacuzzi or Whirlpool tubs, though both are brand names.
One piece spas are usually shallower than wooden tubs, usually being 32" to 36" in height to fit through doors and narrow hallways. Cranes are occasionally used to place one piece spas in a backyard or other location that does not have adequate clearance for carrying the tub.
Spas usually have between one and four water pumps, with one circulation pump serving the heating and filtration water loop and the other(s) driving the hydrotherapy jets. Sophisticated computer controls are now common and many tubs now are equipped with extensive lighting, sound systems, and even flat panel televisions with DVD players.
# Construction of a one-piece spa
The spa shell is the exterior of the tub, and is composed of a surface and an understructure that are bonded together during the manufacturing process. The surface is the source of the color, look and feel of the spa, so it should resist deterioration due to the sun, spa chemicals, or normal wear and tear. Some high-end shells have special coatings to make them more stain resistant or have anti-bacterial ingredients molded into the shell material.
There two primary methods used for manufacturing one piece spa shells:
- vacuum forming of an acrylic base by placing the sheet over a mold and heating with an overhead heater while pulling a vacuum on the mold
- rotational molding: involves placing polyethylene powder in an aluminum mold which is then heated and spun in a large oven so that the plastic melts and takes the form of the mold.
The understructure of the shell provides the strength needed to support hundreds of gallons of water and the weight of the bathers (the cabinet is not normally part of the weight-bearing structure). The substructure is generally made of FRP (commonly called fiberglass), though some companies use ABS or other plastics. Some manufacturers build a self-supporting shell, while others use secondary supports of wood or metal under the seats or in high-stress areas to reduce the amount of FRP required. Some companies use a perimeter frame of wood or metal to support the rim.
The plumbing of the spa consists of several distinct systems:
- A pressure system delivering water to the jets
- A suction system returning water to the pumps.
- A filtration system - the plumbing has to incorporate a filter system to help clean the water. Some models use a separate small 24/7 filter pump while others use programmed settings of the main pumps.
- Induced air - The jets may use a venturi effect to incorporate air into the water stream for a lighter massage effect; this requires another set of hoses.
- Some models use an air blower to force air through a separate set of jets for a different "bubbly" massage effect; this is a separate system from the induced air.
- An ozone system - ozonation is a common adjunct to water maintenance, and if installed will have its own set of hoses and fittings.
The spa cabinet is the skirting around the hot tub, and serves as both an enclosure for the plumbing and a decorative wrap. For many years, spa cabinetry was made of wood, most commonly redwood or cedar, and this is still a popular choice. Wood cabinets require regular maintenance, though, especially in climates where they are exposed to severe weathering. Synthetic materials are increasingly popular because they are seen as requiring relatively little maintenance to keep their appearance.
# Energy efficiency
Effective insulation greatly improves the energy efficiency of a spa. There are several different styles of spa insulation: some manufacturers fill the entire cabinet with foam, while others insulate the underside of the shell, the inside of the cabinet, or both. Not surprisingly, many manufacturers advertise the superiority of their approach to insulation, but few independent side-by-side comparisons are available. The spa pump and hot tub heater represent most of the power consumption in a hot tub and vary in use of power depending on their size.
Energy efficiency of the tubs has been studied by the Pacific Gas and Electric Company[1]. The industry has responded to the study.[2]
After this study, both the California Energy Commission and National Resources Canada have taken an interest in the energy efficiency of portable spas (late 2006).
California's portable electric spa listing include R Values of thermal insulation, and standby watts.[3][4]
# Alternative Designs
Metal stock tanks have also been used as a cheap alternative for a hot tub, though the lack of insulation makes heating difficult. There are also hot tubs that use firm insulation coated in vinyl to hold in water, but these must be short due to the weight of water and the relatively low tensional strength of insulation and vinyl.
# Sanitation and chemistry
Maintaining hot tub water sanitation and chemistry is necessary to prevent the spread of disease as well as damage to the tub. In addition to the use of a pump and micrometre-range particulate filter, bromine, chlorine or mineral sanitizers are almost always used as a primary sanitizer, and often supplemented with an ozone generator, UV sterilization, and/or silver and copper ion generator (also known as a "spa ionizer"). [5] If only chlorine is used, a primary algaecide such as polyquat may be additionally needed, since these microbes are more resistant to chlorine than are most bacteria.
To periodically remove any stubborn microorganisms, or in the event of poor water sanitation, "shocking" the hot tub is recommended. This can be done with either potassium monopersulfate (usually referred to as "non-chlorine shock"), or a relatively large dose of granulated chlorine. The hot tub should not be used for a period of time after starting the shock treatment, typically 15 minutes for potassium monopersulfate and 8 hours for chlorine.
Maintaining the water chemistry involves keeping the pH, total alkalinity, and calcium hardness within acceptable margins. Most important are the pH and total alkalinity: if not maintained, the primary sanitizer (chlorine, bromine or mineral sanitizer) will not function effectively.[6] Also, severe problems with the water chemistry may cause metal parts of the tub's plumbing to corrode, damaging or destroying them. The Langlier Saturation Index is important to determine and maintain properly, so that calcium and magnesium deposits do not form in the water heater
Poor hot tub sanitation, whether by improper design or failure of the sanitation system, can result in disease transmission and litigation. [7] It is recommended to have multiple sanitation systems to prevent system failure if one sanitation subsystem fails.
# Commonly used terms
Hot tub - name originally given to the earliest tubs that were round, made of wood, and located outdoors; now is commonly used interchangeably with the phrases 'home spa' and 'portable spa'.
Home spa - generally made with a plastic shell; surrounding cabinet may be made of wood or synthetic materials; can be used to describe an above ground, in-ground, indoor or outdoor spa.
Portable hot tub/portable home spa - name for any hot tub/home spa that is pre-assembled and sits above ground; actual size and features of a portable hot tub vary widely, from small portable hot tubs that weigh only a few hundred pounds and plug into a household outlet to large tubs that weigh several thousand pounds and require specific installation methods and electrical wiring.
# Stereo systems
Some hot tub models have integrated sound systems. These sound systems are typically made of marine grade components that can withstand the humid environments associated with spas. | https://www.wikidoc.org/index.php/Hot_tub | |
65b696346e5982d49d88ba744a1330dc9a057c51 | wikidoc | Humerus | Humerus
# Overview
The humerus is a long bone in the arm that runs from the shoulder to the elbow. On a skeleton, it fits between the scapula and the ulna. It consists of the following three sections:
- Upper extremity of humerus
- Body of humerus
- Lower extremity of humerus
# Articulations
A bursa lies between the scapula and the chest wall, and allows the scapula to move over the chest wall. Movements of the shoulder are actually often combined movements of the glenohumeral joint as well as movement of the scapula on the chest wall.
The distal end of the humerus (at the elbow) creates a hinge joint with the ulna, allowing only flexion and extension. This happens on the trochlea of the humerus. Two pits at this end of the humerus (the coronoid fossa and the olecranon fossa) allow the ulna room to move, but prevent it from over-flexing/extending.
There is also a pivot joint between the capitulum (sometimes called the capitellum) of the humerus, and the head of the radius. This allows the hand to pronate and supinate (turn to face downwards or upwards).
# Muscle attachments
A variety of muscles attach to the humerus. These enable movement at the elbow and at the shoulder.
The rotator cuff muscles attach at the proximal humerus, and can rotate and abduct the arm at the shoulder.
Some of the forearm muscles, (such as pronator teres, and the flexors and extensors of the wrist) also attach to the distal humerus.
# Actions
- Deltoid has a variety of actions on the top of the arm.
- Pectoralis major, teres major and latissimus dorsi, which all insert at the intertubercular groove of the humerus, adduct and medially rotate the humerus.
- Biceps brachii, brachialis, coracobrachialis, and brachioradialis (which attaches very distally), act to flex the elbow. Biceps however does not attach to the humerus.
- Triceps brachii and anconeus extend the elbow, and attach to the posterior side of the humerus.
# Clinical considerations
The most common type of shoulder (glenohumeral joint) dislocation is an anterior or inferior dislocation of the humerus. This dislocation has the potential to injure the axillary nerve or axillary artery. Signs and symptoms of this dislocation are: a loss of the normal contour of the shoulder, a depression under the acromion that you can feel, and being able to feel the head of humerus in the axilla (armpit).
# Popular culture
Since 'Humerus' is the homonym of 'humorous', it is sometimes referred to in popular culture as 'the funny bone'. However, the funny bone is actually not a bone, but refers to the ulnar nerve situated at the end of the humerus near the elbow. Accidentally hitting the funny bone can cause a tingling sensation (or 'funny' feeling), and possibly a significant amount of pain.
# Additional images
- Diagram of the human shoulder joint
- Human arm bones diagram
- Humerus (right) - anterior view
- Humerus (right) - posterior view
- Left humerus. Anterior view.
- Left humerus. Posterior view.
- The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula.
- Cross-section through the middle of upper arm.
- The Supinator.
ar:عضد
bn:প্রগণ্ডাস্থি
ca:Húmer
da:Humerus
de:Humerus
eo:Humero
id:Tulang lengan atas
it:Omero (anatomia)
he:עצם הזרוע
la:Humerus
lt:Žastikaulis
hu:Felkarcsont
nl:Opperarmbeen
no:Humerus
sk:Ramenná kosť
fi:Olkaluu
sv:Överarmsben
th:กระดูกต้นแขน
uk:Плечова кістка | Humerus
Template:Infobox Bone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
The humerus is a long bone in the arm that runs from the shoulder to the elbow. On a skeleton, it fits between the scapula and the ulna. It consists of the following three sections:
- Upper extremity of humerus
- Body of humerus
- Lower extremity of humerus
# Articulations
A bursa lies between the scapula and the chest wall, and allows the scapula to move over the chest wall. Movements of the shoulder are actually often combined movements of the glenohumeral joint as well as movement of the scapula on the chest wall.
The distal end of the humerus (at the elbow) creates a hinge joint with the ulna, allowing only flexion and extension. This happens on the trochlea of the humerus. Two pits at this end of the humerus (the coronoid fossa and the olecranon fossa) allow the ulna room to move, but prevent it from over-flexing/extending.
There is also a pivot joint between the capitulum (sometimes called the capitellum) of the humerus, and the head of the radius. This allows the hand to pronate and supinate (turn to face downwards or upwards).
# Muscle attachments
A variety of muscles attach to the humerus. These enable movement at the elbow and at the shoulder.
The rotator cuff muscles attach at the proximal humerus, and can rotate and abduct the arm at the shoulder.
Some of the forearm muscles, (such as pronator teres, and the flexors and extensors of the wrist) also attach to the distal humerus.
# Actions
- Deltoid has a variety of actions on the top of the arm.
- Pectoralis major, teres major and latissimus dorsi, which all insert at the intertubercular groove of the humerus, adduct and medially rotate the humerus.
- Biceps brachii, brachialis, coracobrachialis, and brachioradialis (which attaches very distally), act to flex the elbow. Biceps however does not attach to the humerus.
- Triceps brachii and anconeus extend the elbow, and attach to the posterior side of the humerus.
# Clinical considerations
The most common type of shoulder (glenohumeral joint) dislocation is an anterior or inferior dislocation of the humerus. This dislocation has the potential to injure the axillary nerve or axillary artery. Signs and symptoms of this dislocation are: a loss of the normal contour of the shoulder, a depression under the acromion that you can feel, and being able to feel the head of humerus in the axilla (armpit).
# Popular culture
Since 'Humerus' is the homonym of 'humorous', it is sometimes referred to in popular culture as 'the funny bone'. However, the funny bone is actually not a bone, but refers to the ulnar nerve situated at the end of the humerus near the elbow. Accidentally hitting the funny bone can cause a tingling sensation (or 'funny' feeling), and possibly a significant amount of pain.
# Additional images
- Diagram of the human shoulder joint
- Human arm bones diagram
- Humerus (right) - anterior view
- Humerus (right) - posterior view
- Left humerus. Anterior view.
- Left humerus. Posterior view.
- The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula.
- Cross-section through the middle of upper arm.
- The Supinator.
Template:Gray's
Template:Bones of upper extremity
ar:عضد
bn:প্রগণ্ডাস্থি
ca:Húmer
da:Humerus
de:Humerus
eo:Humero
id:Tulang lengan atas
it:Omero (anatomia)
he:עצם הזרוע
la:Humerus
lt:Žastikaulis
hu:Felkarcsont
nl:Opperarmbeen
no:Humerus
sk:Ramenná kosť
fi:Olkaluu
sv:Överarmsben
th:กระดูกต้นแขน
uk:Плечова кістка
Template:Jb1
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Humeral | |
390f20ece3976b12d98302228c186f5d06844b87 | wikidoc | Humidor | Humidor
A humidor is any kind of box or room with constant humidity (and often temperature as well) used to store cigars or pipe tobacco. For private use, small wooden or acrylic glass humidor boxes for a few dozen cigars are used, while cigar shops may have walk-in humidors, sometimes covering a whole floor. Humidors of all sizes use hygrometers to keep track of the humidity levels.
## Maintenance
The ideal humidity in a humidor is around 65-75%. The more empty space, the more readily the humidity will drop.
Humidor cases are typically made nowadays of woodboard with an interior veneer of Spanish-cedar wood or mahogany.
Spanish-cedar is the most frequently used wood for the interior veneer of humidors. It possesses the following desirable characteristics for cigar storage:
- It holds more moisture than most woods, so it helps maintain humidity.
- It imparts its aroma to cigars if they are stored in it for long enough. For the same reason, some cigars are wrapped in Spanish-cedar sheets before they are sold.
- Spanish-cedar wood can repel tobacco beetles. These pinhead-sized beetles can ruin entire stocks of cigars. They eat the tobacco and lay eggs, causing further infestation. They can also be discouraged by ensuring the humidor does not get hotter than 20 °C. The beetle eggs usually only hatch at around 25 °C, although there are also instances where they will hatch at cooler temperatures if the humidity is too high.
Each humidor has to be seasoned after being bought or having been dry for a while. This is done by taking a moist cloth and wiping down the interior to remove any dust. A small container of water is then placed inside the humidor and left for around 12 hours with the lid closed. If the water is gone or mostly gone, then this is repeated for another 24 hours. When the liquid in the container stops evaporating, cigars can be placed in it. The humidifying element or "sponge" keeps the wood moist, which in turn keeps the cigars moist. As well, the use of distilled water is recommended for its lack of minerals, additives, or bacteria.
# Notable humidor brands
- Adorini
- Alfred Dunhill
- Elie Bleu
- Griffin's
- Manning
- Zino Davidoff
- Michel Perrenoud | Humidor
A humidor is any kind of box or room with constant humidity (and often temperature as well) used to store cigars or pipe tobacco. For private use, small wooden or acrylic glass humidor boxes for a few dozen cigars are used, while cigar shops may have walk-in humidors, sometimes covering a whole floor. Humidors of all sizes use hygrometers to keep track of the humidity levels.
## Maintenance
The ideal humidity in a humidor is around 65-75%. The more empty space, the more readily the humidity will drop.
Humidor cases are typically made nowadays of woodboard with an interior veneer of Spanish-cedar wood or mahogany.
Spanish-cedar is the most frequently used wood for the interior veneer of humidors. It possesses the following desirable characteristics for cigar storage:
- It holds more moisture than most woods, so it helps maintain humidity.
- It imparts its aroma to cigars if they are stored in it for long enough. For the same reason, some cigars are wrapped in Spanish-cedar sheets before they are sold.
- Spanish-cedar wood can repel tobacco beetles. These pinhead-sized beetles can ruin entire stocks of cigars. They eat the tobacco and lay eggs, causing further infestation. They can also be discouraged by ensuring the humidor does not get hotter than 20 °C.[1] The beetle eggs usually only hatch at around 25 °C, although there are also instances where they will hatch at cooler temperatures if the humidity is too high.
Each humidor has to be seasoned after being bought or having been dry for a while. This is done by taking a moist cloth and wiping down the interior to remove any dust. A small container of water is then placed inside the humidor and left for around 12 hours with the lid closed. If the water is gone or mostly gone, then this is repeated for another 24 hours. When the liquid in the container stops evaporating, cigars can be placed in it. The humidifying element or "sponge" keeps the wood moist, which in turn keeps the cigars moist. As well, the use of distilled water is recommended for its lack of minerals, additives, or bacteria.
# Notable humidor brands
- Adorini
- Alfred Dunhill
- Elie Bleu
- Griffin's
- Manning
- Zino Davidoff
- Michel Perrenoud | https://www.wikidoc.org/index.php/Humidor | |
03ddf38b6b8677f50c2e52148966c0d8d5ae389f | wikidoc | Hyaline | Hyaline
The term hyaline, (Hel. hualinòs = glassish) literally refers to a substance with a glass-like appearance.
In common medical histopathological usage, hyaline is a substance with a glassy, pink appearance after haematoxylin and eosin staining—most often an acellular, proteinaceous material. Hyaline cartilage is the clear, shiny ("glass-like") cartilage of articular joints.
In other scientific fields, hyaline may refer a specifically colorless and transparent substance. | Hyaline
The term hyaline, (Hel. hualinòs = glassish) literally refers to a substance with a glass-like appearance.
In common medical histopathological usage, hyaline is a substance with a glassy, pink appearance after haematoxylin and eosin staining—most often an acellular, proteinaceous material. Hyaline cartilage is the clear, shiny ("glass-like") cartilage of articular joints.
In other scientific fields, hyaline may refer a specifically colorless and transparent substance. | https://www.wikidoc.org/index.php/Hyaline | |
9eef8830039aac5bc3bffcb5ff2219dc565f0855 | wikidoc | Hydride | Hydride
Hydride is the name given to the negative ion of hydrogen, H−. Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe compounds of hydrogen with other elements, particularly those of groups 1–16. The variety of compounds formed by hydrogen is vast, arguably greater than that of any other element. Every element of the periodic table (except some noble gases) forms one or more hydrides. These may be classified into three main types by the predominant nature of their bonding:
- Saline hydrides, which have significant ionic character,
- Covalent hydrides, which include the hydrocarbons and many other compounds, and
- Interstitial hydrides, which may be described as having metallic bonding.
# Hydride ion
Aside from electride, the hydride ion is the simplest possible anion, consisting of two electrons and a proton. Hydrogen has a relatively low electron affinity, 72.77 kJ/mol, thus hydride is so basic that it is unknown in solution. The reactivity of the hypothetic hydride ion is dominated by its exothermic protonation to give dihydrogen:
As a result, the hydride ion is one of the strongest bases known. It would extract protons from almost any hydrogen-containing species. The low electron affinity of hydrogen and the strength of the H–H bond (436 kJ/mol) means that the hydride ion would also be a strong reducing agent:
# Ionic hydrides
In ionic hydrides the hydrogen behaves as a halogen and obtains an electron from the metal to form a hydride ion (H−), thereby attaining the stable electron configuration of helium by filling its 1s-orbital. The other element is a metal more electropositive than hydrogen, usually one of the alkali metals or alkaline earth metals. The hydrides are called binary if they only involve two elements including hydrogen. Chemical formulae for binary ionic hydrides typically MH (as in LiH). As the charge on the metal increases, the M-H bonding becomes more covalent as in MgH2 and AlH3. Ionic hydrides are commonly encountered as basic reagents in organic synthesis:
Such reactions are heterogeneous, the KH does not dissolve. Typical solvents for such reactions are ethers. Water cannot serve as a medium for pure ionic hydrides or LAH because the hydride ion is a stronger base than hydroxide. Hydrogen gas is liberated in a typical acid-base reaction.
Alkali metal hydrides react with metal halides. Lithium aluminium hydride (often abbreviated as LAH) arises from reactions with aluminium chloride.
# Covalent hydrides
In covalent hydrides, hydrogen is covalently bonded to more electropositive element such as p-block (boron, aluminium, and Group 4-7) elements as well as beryllium. Common compounds include the hydrocarbons and ammonia could be considered as hydrides of carbon and nitrogen, respectively. Charge neutral covalent hydrides that are molecular are often volatile at room temperature and atmospheric pressure. Some covalent hydrides are not volatile because they are polymeric—i.e. nonmolecular—such as the binary hydrides of aluminium and beryllium. Replacing some hydrogen atoms in such compounds with larger ligands, one obtains molecular derivatives. For example, diisobutylaluminium hydride (DIBAL) consists of two aluminium centers bridged by hydride ligands. Hydrides that are soluble in common solvents are widely used in organic synthesis. Particularly common are sodium borohydride (NaBH4) and lithium aluminum hydride and hindered reagents such as DIBAL.
# Transition metal hydrido complexes
Most transition metal complexes form molecular compounds described as hydrides. Usually such compounds are discussed in the context of organometallic chemistry. Transition metal hydrides are intermediates in many industrial processes that rely on metal catalysts, such as hydroformylation, hydrogenation, and hydrodesulfurization. Two famous examples, HCo(CO)4 and H2Fe(CO)4, are acidic thus demonstrating that the term hydride is used very broadly. Deprotonation of dihydrogen complexes gives metal hydrides. The anion 2- is a rare example of a molecular homoleptic metal hydride.
# Interstitial hydrides of the transitional metals
Structurally related to the saline hydrides, the transition metals form binary hydrides which are often non-stoichiometric, with variable amounts of hydrogen atoms in the lattice, where they can migrate through it. In materials engineering, the phenomenon of hydrogen embrittlement is a consequence of interstitial hydrides. Palladium absorbs up to 900 times its own volume of hydrogen at room temperatures, forming palladium hydride, and was therefore once thought as a means to carry hydrogen for vehicular fuel cells. Hydrogen gas is liberated proportional to the applied temperature and pressure but not to the chemical composition.
Interstitial hydrides show certain promise as a way for safe hydrogen storage. During last 25 years many interstitial hydrides were developed that readily absorb and discharge hydrogen at room temperature and atmospheric pressure. They are usually based on intermetallic compounds and solid-solution alloys. However, their application is still limited, as they are capable of storing only about 2 weight percent of hydrogen, which is not enough for automotive applications.
# Nomenclature
Various metal hydrides are currently being studied for use as a means of hydrogen storage in fuel cell-powered electric cars and batteries. They also have important uses in organic chemistry as powerful reducing agents, and many promising uses in hydrogen economy.
The following is a list of main group hydride nomenclature:
- alkali and alkaline earth metals: metal hydride
- boron: borane and rest of the group as metal hydride
- carbon: alkanes, alkenes, alkynes, and all hydrocarbons
- silicon: silane
- germanium: germane
- tin: stannane
- lead: plumbane
- nitrogen: ammonia ('azane' when substituted), hydrazine
- phosphorus: phosphine ('phosphane' when substituted)
- arsenic: arsine ('arsane' when substituted)
- antimony: stibine ('stibane' when substituted)
- bismuth: bismuthine ('bismuthane' when substituted)
According to the convention above, the following are "hydrogen compounds" and not "hydrides":
- oxygen: water ('oxidane' when substituted), hydrogen peroxide
- sulfur: hydrogen sulfide ('sulfane' when substituted)
- selenium: hydrogen selenide ('selane' when substituted)
- tellurium: hydrogen telluride ('tellane' when substituted)
- halogens: hydrogen halides
Examples:
- nickel hydride: used in NiMH batteries
- palladium hydride: electrodes in cold fusion experiments
- lithium aluminium hydride: a powerful reducing agent used in organic chemistry
- sodium borohydride: selective specialty reducing agent, hydrogen storage in fuel cells
- sodium hydride: a powerful base used in organic chemistry
- diborane: reducing agent, rocket fuel, semiconductor dopant, catalyst, used in organic synthesis; also borane, pentaborane and decaborane
- arsine: used for doping semiconductors
- stibine: used in semiconductor industry
- phosphine: used for fumigation
- silane: many industrial uses, e.g. manufacture of composite materials and water repellents
- ammonia: coolant, fertilizer, many other industrial uses
- hydrogen sulfide: component of natural gas, important source of sulfur
- Chemically, even water and hydrocarbons could be considered hydrides.
## Isotopes of hydride
Protide, deuteride, and tritide are used to describe ions or compounds, which contain enriched hydrogen-1, deuterium or tritium, respectively.
## Precedence convention
According to IUPAC convention, by precedence (stylized electronegativity), hydrogen falls between group 15 and group 16 elements. Therefore we have NH3, 'nitrogen hydride' (ammonia), versus H2O, 'hydrogen oxide' (water). | Hydride
Hydride is the name given to the negative ion of hydrogen, H−. Although this ion does not exist except in extraordinary conditions, the term hydride is widely applied to describe compounds of hydrogen with other elements, particularly those of groups 1–16. The variety of compounds formed by hydrogen is vast, arguably greater than that of any other element. Every element of the periodic table (except some noble gases) forms one or more hydrides. These may be classified into three main types by the predominant nature of their bonding:
- Saline hydrides, which have significant ionic character,
- Covalent hydrides, which include the hydrocarbons and many other compounds, and
- Interstitial hydrides, which may be described as having metallic bonding.
# Hydride ion
Aside from electride, the hydride ion is the simplest possible anion, consisting of two electrons and a proton. Hydrogen has a relatively low electron affinity, 72.77 kJ/mol, thus hydride is so basic that it is unknown in solution. The reactivity of the hypothetic hydride ion is dominated by its exothermic protonation to give dihydrogen:
As a result, the hydride ion is one of the strongest bases known. It would extract protons from almost any hydrogen-containing species. The low electron affinity of hydrogen and the strength of the H–H bond (436 kJ/mol) means that the hydride ion would also be a strong reducing agent:
# Ionic hydrides
In ionic hydrides the hydrogen behaves as a halogen and obtains an electron from the metal to form a hydride ion (H−), thereby attaining the stable electron configuration of helium by filling its 1s-orbital. The other element is a metal more electropositive than hydrogen, usually one of the alkali metals or alkaline earth metals. The hydrides are called binary if they only involve two elements including hydrogen. Chemical formulae for binary ionic hydrides typically MH (as in LiH). As the charge on the metal increases, the M-H bonding becomes more covalent as in MgH2 and AlH3. Ionic hydrides are commonly encountered as basic reagents in organic synthesis:
Such reactions are heterogeneous, the KH does not dissolve. Typical solvents for such reactions are ethers. Water cannot serve as a medium for pure ionic hydrides or LAH because the hydride ion is a stronger base than hydroxide. Hydrogen gas is liberated in a typical acid-base reaction.
Alkali metal hydrides react with metal halides. Lithium aluminium hydride (often abbreviated as LAH) arises from reactions with aluminium chloride.
# Covalent hydrides
In covalent hydrides, hydrogen is covalently bonded to more electropositive element such as p-block (boron, aluminium, and Group 4-7) elements as well as beryllium. Common compounds include the hydrocarbons and ammonia could be considered as hydrides of carbon and nitrogen, respectively. Charge neutral covalent hydrides that are molecular are often volatile at room temperature and atmospheric pressure. Some covalent hydrides are not volatile because they are polymeric—i.e. nonmolecular—such as the binary hydrides of aluminium and beryllium. Replacing some hydrogen atoms in such compounds with larger ligands, one obtains molecular derivatives. For example, diisobutylaluminium hydride (DIBAL) consists of two aluminium centers bridged by hydride ligands. Hydrides that are soluble in common solvents are widely used in organic synthesis. Particularly common are sodium borohydride (NaBH4) and lithium aluminum hydride and hindered reagents such as DIBAL.
# Transition metal hydrido complexes
Most transition metal complexes form molecular compounds described as hydrides. Usually such compounds are discussed in the context of organometallic chemistry. Transition metal hydrides are intermediates in many industrial processes that rely on metal catalysts, such as hydroformylation, hydrogenation, and hydrodesulfurization. Two famous examples, HCo(CO)4 and H2Fe(CO)4, are acidic thus demonstrating that the term hydride is used very broadly. Deprotonation of dihydrogen complexes gives metal hydrides. The anion [ReH9]2- is a rare example of a molecular homoleptic metal hydride.
# Interstitial hydrides of the transitional metals
Structurally related to the saline hydrides, the transition metals form binary hydrides which are often non-stoichiometric, with variable amounts of hydrogen atoms in the lattice, where they can migrate through it. In materials engineering, the phenomenon of hydrogen embrittlement is a consequence of interstitial hydrides. Palladium absorbs up to 900 times its own volume of hydrogen at room temperatures, forming palladium hydride, and was therefore once thought as a means to carry hydrogen for vehicular fuel cells. Hydrogen gas is liberated proportional to the applied temperature and pressure but not to the chemical composition.
Interstitial hydrides show certain promise as a way for safe hydrogen storage. During last 25 years many interstitial hydrides were developed that readily absorb and discharge hydrogen at room temperature and atmospheric pressure. They are usually based on intermetallic compounds and solid-solution alloys. However, their application is still limited, as they are capable of storing only about 2 weight percent of hydrogen, which is not enough for automotive applications.
# Nomenclature
Various metal hydrides are currently being studied for use as a means of hydrogen storage in fuel cell-powered electric cars and batteries. They also have important uses in organic chemistry as powerful reducing agents, and many promising uses in hydrogen economy.
The following is a list of main group hydride nomenclature:
- alkali and alkaline earth metals: metal hydride
- boron: borane and rest of the group as metal hydride
- carbon: alkanes, alkenes, alkynes, and all hydrocarbons
- silicon: silane
- germanium: germane
- tin: stannane
- lead: plumbane
- nitrogen: ammonia ('azane' when substituted), hydrazine
- phosphorus: phosphine ('phosphane' when substituted)
- arsenic: arsine ('arsane' when substituted)
- antimony: stibine ('stibane' when substituted)
- bismuth: bismuthine ('bismuthane' when substituted)
According to the convention above, the following are "hydrogen compounds" and not "hydrides":
- oxygen: water ('oxidane' when substituted), hydrogen peroxide
- sulfur: hydrogen sulfide ('sulfane' when substituted)
- selenium: hydrogen selenide ('selane' when substituted)
- tellurium: hydrogen telluride ('tellane' when substituted)
- halogens: hydrogen halides
Examples:
- nickel hydride: used in NiMH batteries
- palladium hydride: electrodes in cold fusion experiments
- lithium aluminium hydride: a powerful reducing agent used in organic chemistry
- sodium borohydride: selective specialty reducing agent, hydrogen storage in fuel cells
- sodium hydride: a powerful base used in organic chemistry
- diborane: reducing agent, rocket fuel, semiconductor dopant, catalyst, used in organic synthesis; also borane, pentaborane and decaborane
- arsine: used for doping semiconductors
- stibine: used in semiconductor industry
- phosphine: used for fumigation
- silane: many industrial uses, e.g. manufacture of composite materials and water repellents
- ammonia: coolant, fertilizer, many other industrial uses
- hydrogen sulfide: component of natural gas, important source of sulfur
- Chemically, even water and hydrocarbons could be considered hydrides.
## Isotopes of hydride
Protide, deuteride, and tritide are used to describe ions or compounds, which contain enriched hydrogen-1, deuterium or tritium, respectively.
## Precedence convention
According to IUPAC convention, by precedence (stylized electronegativity), hydrogen falls between group 15 and group 16 elements. Therefore we have NH3, 'nitrogen hydride' (ammonia), versus H2O, 'hydrogen oxide' (water). | https://www.wikidoc.org/index.php/Hydride | |
c31f05c6ea632bbc64540cfb390c0247346c2566 | wikidoc | Hygiene | Hygiene
Hygiene refers to practices associated with ensuring good health and cleanliness. The scientific term "hygiene" refers to the maintenance of health and healthy living. The term appears in phrases such as personal hygiene, domestic hygiene, dental hygiene, and occupational hygiene and is frequently used in connection with public health. The term "hygiene" is derived from Hygieia, the Greek goddess of health, cleanliness and sanitation. Hygiene is also a science that deals with the promotion and preservation of health. Also called hygienics.
# Personal hygiene
- Washing the body and hair frequently.
- Frequent washing of hands and face.
- Oral hygiene—taking care of the teeth and gums, and treating or preventing bad breath
Daily brushing (with toothpaste) and flossing the teeth, to prevent tooth decay and gum disease. This also helps treat and prevent bad breath.
Chewing gum or rinsing mouth with antibacterial mouthwashes (such as Listerine) can also dispel bad breath
- Daily brushing (with toothpaste) and flossing the teeth, to prevent tooth decay and gum disease. This also helps treat and prevent bad breath.
- Chewing gum or rinsing mouth with antibacterial mouthwashes (such as Listerine) can also dispel bad breath
- Cleaning of the clothes and living area.
- Avoiding contact with bodily fluids, such as blood, feces, urine, and vomit.
- Not touching animals before eating, or washing hands thoroughly between animal-touching and eating.
- Holding a tissue over the mouth or using the upper arm/elbow region when coughing or sneezing, rather than a bare hand. Alternatively, washing hands afterwards.
- Suppression of untidy habits, such as nose-picking, touching pimples, etc.
- Not licking fingers before picking up sheets of paper or turning pages in a book. (Rubber fingertip covers and Glycerine-based products are available for this purpose, which are available from stationery stores.)
- Not biting fingernails.
- Wearing clean underwear and clothing daily.
- Washing hands after using the toilet.
- Not sharing towels, combs, hair brushes, and other personal things.
- Changing bedsheets when a new person sleeps on the bed.
# Food and cooking hygiene
The purposes of food and cooking hygiene are to prevent food contamination, the transmission of disease, and to prevent food poisoning. Food and cooking hygiene protocols specify safe ways to handle and prepare food, and safe methods of serving and eating it. Such protocols include
- Cleaning of food-preparation areas and equipment (for example using designated cutting boards for preparing raw meats and vegetables). (Cleaning may involve use of chlorine bleach for sterilization.)
- Careful avoidance of meats contaminated by trichina worms, salmonella, and other pathogens; or thorough cooking of questionable meats.
- Extreme care in preparing raw foods, such as sushi and sashimi.
- Institutional dish sanitizing by washing with soap and clean water.
- Washing of hands after touching uncooked food when preparing meals.
- Not using the same utensils to prepare different foods.
- Not sharing cutlery when eating.
- Not licking fingers or hands while or after eating.
- Not reusing serving utensils that have been licked.
- Proper storage of food so as to prevent contamination by vermin.
- Refrigeration of foods (and avoidance of specific foods in environments where refrigeration is or was not feasible).
- Labeling food to indicate when it was produced (or, as food manufacturers prefer, to indicate its "best before" date).
- Proper disposal of uneaten food and packaging.
# Medical hygiene
- Proper bandaging and dressing of injuries.
- Use of protective clothing, such as masks, gowns, caps, eyewear and gloves.
- Sterilization of instruments used in surgical procedures.
- Safe disposal of medical waste.
Most of these practices were developed in the 19th century and were well established by the mid-20th century. Some procedures (such as disposal of medical waste) were tightened up as a result of late-20th century disease outbreaks, notably AIDS and Ebola.
# Personal service / served hygiene
- Sterilization of instruments used by hairdressers.
- Sterilization by autoclave of instruments used in body piercing and tattoo marking
- Cleaning hands before eating in food outlets, such as using soap to wash or wet wipe to mop up
# History of hygienic practices
Elaborate codes of hygiene can be found in several Hindu texts such as the Manusmriti and the Vishnu Purana. Bathing is one of the five Nitya karmas (daily duties) in Sikhism, not performing which leads to sin according to some scriptures. These codes were based on the notion of ritual purity and were not informed by an understanding of the causes of diseases and their means of transmission. However, some of the ritual-purity codes did improve hygiene, from an epidemiological point of view, more or less by accident.
Regular bathing was a hallmark of Roman civilization. Elaborate baths were constructed in urban areas to serve the public, who typically demanded the infrastructure to maintain personal cleanliness. The complexes usually consisted of large, swimming pool-like baths, smaller cold and hot pools, saunas, and spa-like facilities where individuals could be depilated, oiled, and massaged. Water was constantly changed by an aqueduct-fed flow. Bathing outside of urban centers involved smaller, less elaborate bathing facilities, or simply the use of clean bodies of water. Roman cities also had large sewers, such as Rome's Cloaca Maxima, into which public and private latrines drained. Romans didn't have demand-flush toilets but did have some toilets with a continuous flow of water under them. (Similar toilets are seen in Acre Prison in the film Exodus.)
Until the late 19th Century, only the elite in Western cities typically possessed indoor facilities for relieving bodily functions. The poorer majority used communal facilities built above cesspools in backyards and courtyards. This changed after Dr. John Snow discovered that cholera was transmitted by the fecal contamination of water. Though it took decades for his findings to gain wide acceptance, governments and sanitary reformers were eventually convinced of the health benefits of using sewers to keep human waste from contaminating water. This encouraged the widespread adoption of both the flush toilet and the moral imperative that bathrooms should be indoors and as private as possible.
## Europe
Contrary to popular belief, bathing and sanitation were not lost in Europe with the collapse of the Roman Empire. As a matter of fact, soapmaking first became an established trade during the so-called "Dark Ages." The Romans used scented oils (mostly from Egypt), among other alternatives. Also, contrary to myth, chamber pots were not emptied out the window and into streets in the European Middle Ages—this was instead a Roman practice. Bathing in fact did not fall out of fashion in Europe until shortly after the Renaissance, replaced by the heavy use of sweat-bathing and perfume, as it was thought in Europe that water could carry disease into the body through the skin. (Water, in fact, does carry disease, but more often if it is drunk than if one bathes in it; and water only carries disease if it is contaminated by pathogens.) Modern sanitation as we know it was not widely adopted until the 19th and 20th centuries. According to medieval historian Lynn Thorndike, people in Medieval Europe probably bathed more than Westerners did in the 19th century.
# Grooming
The related term personal grooming/grooming means to enhance one's physical appearance or appeal for others, by removing obvious imperfections in one's appearance or improving one's hygiene.
Grooming in humans typically includes bathroom activities such as primping: washing and cleansing the hair, combing it to extract tangles and snarls, and styling. It can also include cosmetic care of the body, such as shaving and other forms of depilation.
# Academic resources
- International Journal of Hygiene and Environmental Health, ISSN: 1438-4639, Elsevier | Hygiene
Hygiene refers to practices associated with ensuring good health and cleanliness. The scientific term "hygiene" refers to the maintenance of health and healthy living. The term appears in phrases such as personal hygiene, domestic hygiene, dental hygiene, and occupational hygiene and is frequently used in connection with public health. The term "hygiene" is derived from Hygieia, the Greek goddess of health, cleanliness and sanitation. Hygiene is also a science that deals with the promotion and preservation of health. Also called hygienics.
# Personal hygiene
- Washing the body and hair frequently.
- Frequent washing of hands and face.
- Oral hygiene—taking care of the teeth and gums, and treating or preventing bad breath
Daily brushing (with toothpaste) and flossing the teeth, to prevent tooth decay and gum disease. This also helps treat and prevent bad breath.
Chewing gum or rinsing mouth with antibacterial mouthwashes (such as Listerine) can also dispel bad breath
- Daily brushing (with toothpaste) and flossing the teeth, to prevent tooth decay and gum disease. This also helps treat and prevent bad breath.
- Chewing gum or rinsing mouth with antibacterial mouthwashes (such as Listerine) can also dispel bad breath
- Cleaning of the clothes and living area.
- Avoiding contact with bodily fluids, such as blood, feces, urine, and vomit.
- Not touching animals before eating, or washing hands thoroughly between animal-touching and eating.
- Holding a tissue over the mouth or using the upper arm/elbow region when coughing or sneezing, rather than a bare hand. Alternatively, washing hands afterwards.
- Suppression of untidy habits, such as nose-picking, touching pimples, etc.
- Not licking fingers before picking up sheets of paper or turning pages in a book. (Rubber fingertip covers and Glycerine-based products are available for this purpose, which are available from stationery stores.)
- Not biting fingernails.
- Wearing clean underwear and clothing daily.
- Washing hands after using the toilet.
- Not sharing towels, combs, hair brushes, and other personal things.
- Changing bedsheets when a new person sleeps on the bed.
# Food and cooking hygiene
The purposes of food and cooking hygiene are to prevent food contamination, the transmission of disease, and to prevent food poisoning. Food and cooking hygiene protocols specify safe ways to handle and prepare food, and safe methods of serving and eating it. Such protocols include
- Cleaning of food-preparation areas and equipment (for example using designated cutting boards for preparing raw meats and vegetables). (Cleaning may involve use of chlorine bleach for sterilization.)
- Careful avoidance of meats contaminated by trichina worms, salmonella, and other pathogens; or thorough cooking of questionable meats.
- Extreme care in preparing raw foods, such as sushi and sashimi.
- Institutional dish sanitizing by washing with soap and clean water.
- Washing of hands after touching uncooked food when preparing meals.
- Not using the same utensils to prepare different foods.
- Not sharing cutlery when eating.
- Not licking fingers or hands while or after eating.
- Not reusing serving utensils that have been licked.
- Proper storage of food so as to prevent contamination by vermin.
- Refrigeration of foods (and avoidance of specific foods in environments where refrigeration is or was not feasible).
- Labeling food to indicate when it was produced (or, as food manufacturers prefer, to indicate its "best before" date).
- Proper disposal of uneaten food and packaging.
# Medical hygiene
- Proper bandaging and dressing of injuries.
- Use of protective clothing, such as masks, gowns, caps, eyewear and gloves.
- Sterilization of instruments used in surgical procedures.
- Safe disposal of medical waste.
Most of these practices were developed in the 19th century and were well established by the mid-20th century. Some procedures (such as disposal of medical waste) were tightened up as a result of late-20th century disease outbreaks, notably AIDS and Ebola.
# Personal service / served hygiene
- Sterilization of instruments used by hairdressers.
- Sterilization by autoclave of instruments used in body piercing and tattoo marking
- Cleaning hands before eating in food outlets, such as using soap to wash or wet wipe to mop up
# History of hygienic practices
Elaborate codes of hygiene can be found in several Hindu texts such as the Manusmriti and the Vishnu Purana.[1] Bathing is one of the five Nitya karmas (daily duties) in Sikhism, not performing which leads to sin according to some scriptures. These codes were based on the notion of ritual purity and were not informed by an understanding of the causes of diseases and their means of transmission. However, some of the ritual-purity codes did improve hygiene, from an epidemiological point of view, more or less by accident.
Regular bathing was a hallmark of Roman civilization.[citation needed] Elaborate baths were constructed in urban areas to serve the public, who typically demanded the infrastructure to maintain personal cleanliness. The complexes usually consisted of large, swimming pool-like baths, smaller cold and hot pools, saunas, and spa-like facilities where individuals could be depilated, oiled, and massaged. Water was constantly changed by an aqueduct-fed flow. Bathing outside of urban centers involved smaller, less elaborate bathing facilities, or simply the use of clean bodies of water. Roman cities also had large sewers, such as Rome's Cloaca Maxima, into which public and private latrines drained. Romans didn't have demand-flush toilets but did have some toilets with a continuous flow of water under them. (Similar toilets are seen in Acre Prison in the film Exodus.)
Until the late 19th Century, only the elite in Western cities typically possessed indoor facilities for relieving bodily functions. The poorer majority used communal facilities built above cesspools in backyards and courtyards. This changed after Dr. John Snow discovered that cholera was transmitted by the fecal contamination of water. Though it took decades for his findings to gain wide acceptance, governments and sanitary reformers were eventually convinced of the health benefits of using sewers to keep human waste from contaminating water. This encouraged the widespread adoption of both the flush toilet and the moral imperative that bathrooms should be indoors and as private as possible.[2]
## Europe
Contrary to popular belief, bathing and sanitation were not lost in Europe with the collapse of the Roman Empire. As a matter of fact, soapmaking first became an established trade during the so-called "Dark Ages." The Romans used scented oils (mostly from Egypt), among other alternatives. Also, contrary to myth, chamber pots were not emptied out the window and into streets in the European Middle Ages—this was instead a Roman practice. Bathing in fact did not fall out of fashion in Europe until shortly after the Renaissance, replaced by the heavy use of sweat-bathing and perfume, as it was thought in Europe that water could carry disease into the body through the skin. (Water, in fact, does carry disease, but more often if it is drunk than if one bathes in it; and water only carries disease if it is contaminated by pathogens.) Modern sanitation as we know it was not widely adopted until the 19th and 20th centuries. According to medieval historian Lynn Thorndike, people in Medieval Europe probably bathed more than Westerners did in the 19th century.[3]
# Grooming
The related term personal grooming/grooming means to enhance one's physical appearance or appeal for others, by removing obvious imperfections in one's appearance or improving one's hygiene.
Grooming in humans typically includes bathroom activities such as primping: washing and cleansing the hair, combing it to extract tangles and snarls, and styling. It can also include cosmetic care of the body, such as shaving and other forms of depilation.
# Academic resources
- International Journal of Hygiene and Environmental Health, ISSN: 1438-4639, Elsevier | https://www.wikidoc.org/index.php/Hygiene | |
e4d0ca6fa7f3854d2c39dd61d3f7fb9da6a8abed | wikidoc | Hyphema | Hyphema
# Overview
A hyphema is the collection of blood in the anterior chamber of the eye. Visible as a reddish tinge in the anterior chamber, hyphemas are frequently caused by blunt trauma to the eye and may partially or completely block vision. When the anterior chamber is filled completely with blood, the eye appears black and is commonly known as an "eight ball hemorrhage".
A long-standing hyphema may result in hemosiderosis and heterochromia. Blood accumulation may also cause an elevation of the intraocular pressure.
# Treatment
First Aid for Hyphema (blood in the anterior chamber of the eye) includes bed rest with head elevated by 45-60 degrees with both eyes closed (not patched or bandaged), application of ice-pack, avoidance of straining during bowel movements and while bending over, and during any sexual activity. Medication to reduce eye-pressure and corticosteriods, both as eye-drops, should be started. No aspirin or NSAIDs. If pain is severe use Paracetamol. | Hyphema
# Overview
A hyphema is the collection of blood in the anterior chamber of the eye. Visible as a reddish tinge in the anterior chamber, hyphemas are frequently caused by blunt trauma to the eye and may partially or completely block vision. When the anterior chamber is filled completely with blood, the eye appears black and is commonly known as an "eight ball hemorrhage".
A long-standing hyphema may result in hemosiderosis and heterochromia.[1] Blood accumulation may also cause an elevation of the intraocular pressure.
# Treatment
First Aid for Hyphema (blood in the anterior chamber of the eye) includes bed rest with head elevated by 45-60 degrees with both eyes closed (not patched or bandaged), application of ice-pack, avoidance of straining during bowel movements and while bending over, and during any sexual activity. Medication to reduce eye-pressure and corticosteriods, both as eye-drops, should be started. No aspirin or NSAIDs. If pain is severe use Paracetamol. | https://www.wikidoc.org/index.php/Hyphaema | |
a832c4a396b7acc2f4782b40057aaac9fa887c08 | wikidoc | I-Doser | I-Doser
I-Doser is an application which claims to use binaural beats in order to simulate the effect of various drugs and other altered states of consciousness. Users can purchase "doses" of their choice from the online store. The I-Doser application then plays "dose" files which attempts to create the effects of the chosen drug. Its effects are varied, and the length of the effects depend on your state of mind when the dose is administered and the type of dose.
The user can take various doses in a wide variety of categories ranging from stimulants, anti-depressants, recreational drugs, and hallucinogens.
This natural phenomenon was discovered by Heinrich Wilhelm Dove, a German Neuroscientist in 1839. He claimed that the beat frequency of two sounds of similar frequencies could influence the fundamental state of the brain. This is called Binaural beats.
The dose is not addictive as the effect is extremely subtle. Many first time users claim to feel the effect but are willing to give it another go as it takes thirty to foruty minutes of total concentration to notice it. | I-Doser
Template:Advert
I-Doser is an application which claims to use binaural beats in order to simulate the effect of various drugs and other altered states of consciousness. Users can purchase "doses" of their choice from the online store. The I-Doser application then plays "dose" files which attempts to create the effects of the chosen drug. Its effects are varied, and the length of the effects depend on your state of mind when the dose is administered and the type of dose.
The user can take various doses in a wide variety of categories ranging from stimulants, anti-depressants, recreational drugs, and hallucinogens.
This natural phenomenon was discovered by Heinrich Wilhelm Dove, a German Neuroscientist in 1839. He claimed that the beat frequency of two sounds of similar frequencies could influence the fundamental state of the brain. This is called Binaural beats.
The dose is not addictive as the effect is extremely subtle. Many first time users claim to feel the effect but are willing to give it another go as it takes thirty to foruty minutes of total concentration to notice it.
# External links
- "Official Site" [1]
Template:Neuroscience-stub
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/I-Doser | |
4bf4bba4264bc87ac773e34b7b2043ad5ecd91a5 | wikidoc | IL18RAP | IL18RAP
Interleukin 18 receptor accessory protein, also known as IL18RAP and CDw218b (cluster of differentiation w218b), is a human gene.
# Function
The protein encoded by this gene is an accessory subunit of the heterodimeric receptor for IL18. This protein enhances the IL18 binding activity of IL18R1 (IL1RRP), a ligand binding subunit of IL18 receptor. The coexpression of IL18R1 and this protein is required for the activation of NF-κB and MAPK8 (JNK) in response to IL18.
# Disease association
Variants at IL18RAP have been linked to susceptibility to Coeliac disease. | IL18RAP
Interleukin 18 receptor accessory protein, also known as IL18RAP and CDw218b (cluster of differentiation w218b), is a human gene.[1][2]
# Function
The protein encoded by this gene is an accessory subunit of the heterodimeric receptor for IL18. This protein enhances the IL18 binding activity of IL18R1 (IL1RRP), a ligand binding subunit of IL18 receptor. The coexpression of IL18R1 and this protein is required for the activation of NF-κB and MAPK8 (JNK) in response to IL18.[1]
# Disease association
Variants at IL18RAP have been linked to susceptibility to Coeliac disease.[3] | https://www.wikidoc.org/index.php/IL18RAP | |
feda4fcd0290679be3ef15045d24fea20af45e8a | wikidoc | Illness | Illness
Illness (sometimes referred to as ill-health) can be defined as a state of poor health.
# Introduction
The mode of being healthy includes, as defined by the World Health Organization, " a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" (WHO, 1946). When these conditions are not fulfilled, then one can be considered to have an illness or be ill. Medication and the science of pharmacology is used to cure or reduce symptoms of an illness or medical conditions. Developmental disability is a term used to describe severe, life-long disabilities attributable to mental and/or physical impairments.
# Physical being
Abnormal conditions of the body or mind that cause discomfort, dysfunction, or distress to the person afflicted or those in contact with the person can be deemed an illness. Sometimes the term is used broadly to include injuries, disabilities, syndromes, infections, symptoms, deviant behaviors, and a typical variations of structure and function, while in other contexts these may be considered distinguishable categories. A pathogen or infectious agent is a biological agent that causes disease or illness to its host. A passenger virus is a virus that simply hitchhikes in the body of a person or infects the body without causing symptoms, illness or disease. Foodborne illness or food poisoning is any illness resulting from the consumption of food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites.
# Mental being
Mental illness (or Emotional disability, Cognitive dysfunction) is a broad generic label for a category of illnesses that may include affective or emotional instability, behavioral dysregulation, and/or cognitive dysfunction or impairment. Specific illnesses known as mental illnesses include major depression, generalized anxiety disorder, schizophrenia, and attention deficit hyperactivity disorder, to name a few. Mental illness can be of biological (e.g., anatomical, chemical, or genetic) or psychological (e.g., trauma or conflict) origin. It can impact one’s ability to work or go to school and contribute to problems in relationships. Other generic names for mental illness include “mental disorder”, “psychiatric disorder”, “psychological disorder”, “abnormal psychology”, “emotional disability”, “emotional problems”, or “behavior problem”. The term insanity is used technically as a legal term. Brain damage may occur due to a wide range of conditions, illnesses, or injuries.
A delusion is commonly defined as a fixed false belief and is used in everyday language to describe a belief that is either false, fanciful or derived from deception. In psychiatry, the definition is necessarily more precise and implies that the belief is pathological (the result of an illness or illness process). In the Munchausen syndrome, the sufferer feigns, exaggerates, or creates symptoms of illnesses in himself or herself in order to gain investigation, treatment, attention, or sympathy. Munchausen syndrome by proxy often involves inducing illness in another to the same end.
Mental health consumer is a person who is under treatment for a psychiatric illness or disorder. The term was coined in an attempt to empower those with mental health issues, usually considered a marginalized segment of society. The term suggests that those individuals have a choice in their treatment and that without them there could not exist mental health providers.
# Social being
Social determinants of health are the social conditions in which people live which determine their health. Illnesses are generally related to social, economic, political, and environmental circumstances. Social determinants of health have been recognized by several health organizations such as the Public Health Agency of Canada and the World Health Organization to greatly influence collective and personal well-being.
# Treatments
The governmental involvement is vital and may also be required to study a range of illnesses and treatments. Health care is the prevention, treatment, and management of illness and the preservation of mental and physical well-being through the services offered by the medical, nursing, and allied health professions. The organised provision of such services may constitute a health care system. Before the term "healthcare" became popular, English-speakers referred to medicine or to the health sector and spoke of the treatment and prevention of illness and disease. A patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and is being treated by, or in need of treatment by, a physician or other medical professional. Health consumer or health care consumer is another name for patient, usually used by some governmental agencies, insurance companies, and/or patient groups.
Medical emergencies are injuries or illnesses that pose an immediate threat to a person's health or life which require help from a doctor or hospital. The doctor's specialization of emergency medicine includes techniques for effective handling of medical emergencies and resuscitation of patients. Emergency departments provides initial treatment to patients with a broad spectrum of illnesses and injuries, some of which may be life-threatening and requiring immediate attention.
A drug is any chemical substance other than a food or device that affects the function of living things. Drugs can be used to treat illness, or they can be used recreationally to alter behavior and perception. Medications are typically produced by pharmaceutical companies and are often patented. Those that are not patented are called generic drugs. Some physicians can prescribe approved medications for other than their intended indications, referred as "Off-label use". Marketing information for the drug will list one or more indications, i.e., illnesses or medical conditions for which the drug has been shown to be both safe and effective. A drug overdose occurs when a chemical substance (i.e. drug) is ingested in quantities and/or concentrations large enough to overwhelm the homeostasis of a living organism, causing severe illness or death. Essentially it is a type of poisoning. In the context of biology, poisons are substances that can cause illness.
Bedrest as a medical treatment refers to staying in bed day and night as a treatment for a hangover. Even though most patients in hospitals spend most of their time in the hospital beds, bedrest more often refers to an extended period of recumbence at home.
Human enhancement technologies (HET) are technologies that can be used not simply for treating illness and disability, but also for enhancing human capacities and characteristics. Medication is a licenced drug taken to cure or reduce symptoms of an illness or medical condition. A wheelchair is mobility device that takes the form of a chair on wheels, used by people for whom walking is difficult or impossible due to illness or disability.
Shock therapy is the deliberate and controlled induction of some form of physiological state of shock in an individual for the purpose of psychiatric treatment. Electrotherapy is the use of electrical energy in the treatment of impairments of health and a conditions of abnormal functioning.
# Medical activities
Epidemiology is the scientific study of factors affecting the health and illness of individuals and populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine.
Behavioral medicine is an interdisciplinary field of medicine concerned with the development and integration of psychosocial, behavioral and biomedical knowledge relevant to health and illness. Clinical Global Impression scale to assess treatment response in patients with mental disorders. It's " Improvement scale" requires the clinician to rate how much the patient's illness has improved or worsened relative to a baseline state. Mental confusion and decreased alertness may indicate that a chronic illness has gotten worse. | Illness
Illness (sometimes referred to as ill-health) can be defined as a state of poor health.
# Introduction
The mode of being healthy includes, as defined by the World Health Organization, " [...] a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity" (WHO, 1946). When these conditions are not fulfilled, then one can be considered to have an illness or be ill. Medication and the science of pharmacology is used to cure or reduce symptoms of an illness or medical conditions. Developmental disability is a term used to describe severe, life-long disabilities attributable to mental and/or physical impairments.
# Physical being
Abnormal conditions of the body or mind that cause discomfort, dysfunction, or distress to the person afflicted or those in contact with the person can be deemed an illness. Sometimes the term is used broadly to include injuries, disabilities, syndromes, infections, symptoms, deviant behaviors, and a typical variations of structure and function, while in other contexts these may be considered distinguishable categories. A pathogen or infectious agent is a biological agent that causes disease or illness to its host. A passenger virus is a virus that simply hitchhikes in the body of a person or infects the body without causing symptoms, illness or disease. Foodborne illness or food poisoning is any illness resulting from the consumption of food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites.
# Mental being
Mental illness (or Emotional disability, Cognitive dysfunction) is a broad generic label for a category of illnesses that may include affective or emotional instability, behavioral dysregulation, and/or cognitive dysfunction or impairment. Specific illnesses known as mental illnesses include major depression, generalized anxiety disorder, schizophrenia, and attention deficit hyperactivity disorder, to name a few. Mental illness can be of biological (e.g., anatomical, chemical, or genetic) or psychological (e.g., trauma or conflict) origin. It can impact one’s ability to work or go to school and contribute to problems in relationships. Other generic names for mental illness include “mental disorder”, “psychiatric disorder”, “psychological disorder”, “abnormal psychology”, “emotional disability”, “emotional problems”, or “behavior problem”. The term insanity is used technically as a legal term. Brain damage may occur due to a wide range of conditions, illnesses, or injuries.
A delusion is commonly defined as a fixed false belief and is used in everyday language to describe a belief that is either false, fanciful or derived from deception. In psychiatry, the definition is necessarily more precise and implies that the belief is pathological (the result of an illness or illness process). In the Munchausen syndrome, the sufferer feigns, exaggerates, or creates symptoms of illnesses in himself or herself in order to gain investigation, treatment, attention, or sympathy. Munchausen syndrome by proxy often involves inducing illness in another to the same end.
Mental health consumer is a person who is under treatment for a psychiatric illness or disorder. The term was coined in an attempt to empower those with mental health issues, usually considered a marginalized segment of society. The term suggests that those individuals have a choice in their treatment and that without them there could not exist mental health providers.
# Social being
Social determinants of health are the social conditions in which people live which determine their health. Illnesses are generally related to social, economic, political, and environmental circumstances. Social determinants of health have been recognized by several health organizations such as the Public Health Agency of Canada and the World Health Organization to greatly influence collective and personal well-being.
# Treatments
The governmental involvement is vital and may also be required to study a range of illnesses and treatments. Health care is the prevention, treatment, and management of illness and the preservation of mental and physical well-being through the services offered by the medical, nursing, and allied health professions. The organised provision of such services may constitute a health care system. Before the term "healthcare" became popular, English-speakers referred to medicine or to the health sector and spoke of the treatment and prevention of illness and disease. A patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and is being treated by, or in need of treatment by, a physician or other medical professional. Health consumer or health care consumer is another name for patient, usually used by some governmental agencies, insurance companies, and/or patient groups.
Medical emergencies are injuries or illnesses that pose an immediate threat to a person's health or life which require help from a doctor or hospital. The doctor's specialization of emergency medicine includes techniques for effective handling of medical emergencies and resuscitation of patients. Emergency departments provides initial treatment to patients with a broad spectrum of illnesses and injuries, some of which may be life-threatening and requiring immediate attention.
A drug is any chemical substance other than a food or device that affects the function of living things. Drugs can be used to treat illness, or they can be used recreationally to alter behavior and perception. Medications are typically produced by pharmaceutical companies and are often patented. Those that are not patented are called generic drugs. Some physicians can prescribe approved medications for other than their intended indications, referred as "Off-label use". Marketing information for the drug will list one or more indications, i.e., illnesses or medical conditions for which the drug has been shown to be both safe and effective. A drug overdose occurs when a chemical substance (i.e. drug) is ingested in quantities and/or concentrations large enough to overwhelm the homeostasis of a living organism, causing severe illness or death. Essentially it is a type of poisoning. In the context of biology, poisons are substances that can cause illness.
Bedrest as a medical treatment refers to staying in bed day and night as a treatment for a hangover. Even though most patients in hospitals spend most of their time in the hospital beds, bedrest more often refers to an extended period of recumbence at home.
Human enhancement technologies (HET) are technologies that can be used not simply for treating illness and disability, but also for enhancing human capacities and characteristics. Medication is a licenced drug taken to cure or reduce symptoms of an illness or medical condition. A wheelchair is mobility device that takes the form of a chair on wheels, used by people for whom walking is difficult or impossible due to illness or disability.
Shock therapy is the deliberate and controlled induction of some form of physiological state of shock in an individual for the purpose of psychiatric treatment. Electrotherapy is the use of electrical energy in the treatment of impairments of health and a conditions of abnormal functioning.
# Medical activities
Epidemiology is the scientific study of factors affecting the health and illness of individuals and populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine.
Behavioral medicine is an interdisciplinary field of medicine concerned with the development and integration of psychosocial, behavioral and biomedical knowledge relevant to health and illness. Clinical Global Impression scale to assess treatment response in patients with mental disorders. It's " Improvement scale" requires the clinician to rate how much the patient's illness has improved or worsened relative to a baseline state. Mental confusion and decreased alertness may indicate that a chronic illness has gotten worse. | https://www.wikidoc.org/index.php/Ill-health | |
1281a8a909a3b62e28eebcab246567876b9b62e7 | wikidoc | Imhotep | Imhotep
Imhotep (sometimes spelled Immutef, Im-hotep, or Ii-em-Hotep, Egyptian Template:Unicode Template:Unicode meaning "the one who comes in peace") was an Egyptian polymath, who served under the Third Dynasty king, Djoser, as chancellor to the pharaoh and high priest of the sun god Ra at Heliopolis. He is considered to be the first architect and physician in history known by name . The full list of his titles is: Chancellor of the King of Lower Egypt, First after the King of Upper Egypt, Administrator of the Great Palace, Hereditary nobleman, High Priest of Heliopolis, Builder, Chief Carpenter, Chief Sculptor and Maker of Vases in Chief. Imhotep was one of very few mortals to be depicted as part of a pharaoh's statue. He was one of only a few commoners ever to be accorded divine status after death. The center of his cult was Memphis. From the First Intermediate Period onward Imhotep was also revered as a poet and philosopher. His sayings were famously referred to in poems: I have heard the words of Imhotep and Hordedef with whose discourses men speak so much.
The knowledge of the location of Imhotep's tomb was lost in antiquity and is still unknown, despite efforts to find it. The general consensus is that it is at Saqqara.
# Attribution of achievements and inventions
Much else 'known' about him is hear-say and conjecture. The ancient Egyptians credited him with many inventions. He has e.g. been claimed to be the inventor of the Papyrus scroll, being its oldest known bearer.
## Architecture
As one of the officials of the Pharaoh, Djosèr, he probably designed the Pyramid of Djoser (the Step Pyramid) at Saqqara in Egypt around 2630-2611 BC . He may have been responsible for the first known use of columns in architecture.
As an instigator of Egyptian culture, Imhotep's idealized image lasted well into the Ptolemaic period. The Egyptian historian Manetho credited him with inventing the method of a stone-dressed building during Djoser's reign, however he was not the first to actually build with stone. Stone walling, flooring, lintels, and jambs had appeared sporadically during the Archaic Period, though it is true that a building of the Step Pyramid's size and made entirely out of stone had never before been constructed.
## Medicine
Imhotep is credited with being the founder of Egyptian medicine and with being the author of a medical treatise remarkable for being devoid of magical thinking, the so-called Edwin Smith papyrus containing anatomical observations, ailments, and cures. The surviving papyrus was probably written around 1700 BC but may be a copy of texts a thousand years older. This attribution of authorship is speculative, however..
# Birth myths
According to myth Imhotep's mother was a mortal named Kheredu-ankh, elevated later to semi-divine status by claims that she was the daughter of Banebdjedet. Conversely, as the "Son of Ptah", his mommy woved his head for its shinyniss
# Deification
As Imhotep was considered the inventor of healing, he was also sometimes said to be the one who held up the goddess Nut (the deification of the sky), as the separation of Nut and Geb (the deification of the earth) was said to be what held back chaos. Due to the position this would have placed him in, he was also sometimes said to be Nut's son. In artwork he also is linked with the great goddess, Hathor, who eventually became identified as the wife of Ra. He also was associated with Maat, the goddess who personified the concept of truth, cosmic order, and justice—having created order out of chaos and being responsible for maintaining it.
Two thousand years after his death, his status was raised to that of a deity. He became the god of medicine and healing. He later was linked to Asclepius by the Greeks. He was associated with Amenhotep son of Hapu, who was another deified architect, in the region of Thebes where they were worshipped as "brothers".
# Legacy
The Encyclopedia Britannica says, "The evidence afforded by Egyptian and Greek texts support the view that Imhotep's reputation was very respected in early times... His prestige increased with the lapse of centuries and his temples in Greek times were the centers of medical teachings."
It is Imhotep, says Sir William Osler, who was the real Father of Medicine. "The first figure of a physician to stand out clearly from the mists of antiquity."
An inscription from Upper Egypt, dating from the Ptolemaic period, mentions a famine of seven years during the time of Imhotep. According to the inscription, the reigning pharaoh, Djoser, had a dream in which the Nile god spoke to him. Imhotep is credited with preventing the famine. The obvious parallels with the biblical story of Joseph have long been commented upon. . More recently, the Joseph parallels have led some alternative historians to identify Imhotep with Joseph, and to argue that the supposedly thousand years separating them are indicative of a faulty chronology. . | Imhotep
Imhotep (sometimes spelled Immutef, Im-hotep, or Ii-em-Hotep, Egyptian Template:Unicode Template:Unicode meaning "the one who comes in peace") was an Egyptian polymath,[1] who served under the Third Dynasty king, Djoser, as chancellor to the pharaoh and high priest of the sun god Ra at Heliopolis. He is considered to be the first architect and physician in history known by name [2]. The full list of his titles is: Chancellor of the King of Lower Egypt, First after the King of Upper Egypt, Administrator of the Great Palace, Hereditary nobleman, High Priest of Heliopolis, Builder, Chief Carpenter, Chief Sculptor and Maker of Vases in Chief. Imhotep was one of very few mortals to be depicted as part of a pharaoh's statue. He was one of only a few commoners ever to be accorded divine status after death. The center of his cult was Memphis. From the First Intermediate Period onward Imhotep was also revered as a poet and philosopher. His sayings were famously referred to in poems: I have heard the words of Imhotep and Hordedef with whose discourses men speak so much. [3]
The knowledge of the location of Imhotep's tomb was lost in antiquity [4] and is still unknown, despite efforts to find it. The general consensus is that it is at Saqqara.
# Attribution of achievements and inventions
Much else 'known' about him is hear-say and conjecture. The ancient Egyptians credited him with many inventions. He has e.g. been claimed to be the inventor of the Papyrus scroll,[citation needed] being its oldest known bearer.
## Architecture
As one of the officials of the Pharaoh, Djosèr, he probably designed the Pyramid of Djoser (the Step Pyramid) at Saqqara in Egypt around 2630-2611 BC [5]. He may have been responsible for the first known use of columns in architecture.
As an instigator of Egyptian culture, Imhotep's idealized image lasted well into the Ptolemaic period. The Egyptian historian Manetho credited him with inventing the method of a stone-dressed building during Djoser's reign, however he was not the first to actually build with stone. Stone walling, flooring, lintels, and jambs had appeared sporadically during the Archaic Period, though it is true that a building of the Step Pyramid's size and made entirely out of stone had never before been constructed.
## Medicine
Imhotep is credited[citation needed] with being the founder of Egyptian medicine and with being the author of a medical treatise remarkable for being devoid of magical thinking, the so-called Edwin Smith papyrus containing anatomical observations, ailments, and cures. The surviving papyrus was probably written around 1700 BC but may be a copy of texts a thousand years older. This attribution of authorship is speculative, however.[6].
# Birth myths
According to myth Imhotep's mother was a mortal named Kheredu-ankh, elevated later to semi-divine status by claims that she was the daughter of Banebdjedet.[7] Conversely, as the "Son of Ptah",[8] his mommy woved his head for its shinyniss
# Deification
As Imhotep was considered the inventor of healing, he was also sometimes said to be the one who held up the goddess Nut (the deification of the sky), as the separation of Nut and Geb (the deification of the earth) was said to be what held back chaos. Due to the position this would have placed him in, he was also sometimes said to be Nut's son. In artwork he also is linked with the great goddess, Hathor, who eventually became identified as the wife of Ra. He also was associated with Maat, the goddess who personified the concept of truth, cosmic order, and justice—having created order out of chaos and being responsible for maintaining it.
Two thousand years after his death, his status was raised to that of a deity. He became the god of medicine and healing. He later was linked to Asclepius by the Greeks. He was associated with Amenhotep son of Hapu, who was another deified architect, in the region of Thebes where they were worshipped as "brothers".[9]
# Legacy
The Encyclopedia Britannica says, "The evidence afforded by Egyptian and Greek texts support the view that Imhotep's reputation was very respected in early times... His prestige increased with the lapse of centuries and his temples in Greek times were the centers of medical teachings."
It is Imhotep, says Sir William Osler, who was the real Father of Medicine. "The first figure of a physician to stand out clearly from the mists of antiquity."
An inscription from Upper Egypt, dating from the Ptolemaic period, mentions a famine of seven years during the time of Imhotep. According to the inscription, the reigning pharaoh, Djoser, had a dream in which the Nile god spoke to him. Imhotep is credited with preventing the famine.[10] The obvious parallels with the biblical story of Joseph have long been commented upon. [11]. More recently, the Joseph parallels have led some alternative historians to identify Imhotep with Joseph, and to argue that the supposedly thousand years separating them are indicative of a faulty chronology. [12]. | https://www.wikidoc.org/index.php/Imhotep | |
f8f88cec939793f3f91839a862dd63ca59bd3128 | wikidoc | In vivo | In vivo
In vivo (Latin: within the living) means that which takes place inside an organism. In science, in vivo refers to experimentation done in or on the living tissue of a whole, living organism as opposed to a partial or dead one or a controlled environment. Animal testing and clinical trials are forms of in vivo research.
# in vivo research
This type of research approaches subject experimentation holistically. It is, often, better suited for observing the overall effects of an experiment on its living subject (see in vitro for its description and respective merits). In molecular biology "in vivo" may refer to experimentation done at the cellular level within the natural milieu of intact living cells. Once cells are disrupted and individual parts are tested or analyzed, this is known as "in vitro".
According to Christopher Lipinksi and Andrew Hopkins, fellows with Pfizer Global Research and Development, in vivo research has an advantage in that: Whether the aim is to discover drugs or to gain knowledge of biological systems, the nature and properties of a chemical tool cannot be considered independently of the system it is to be tested in. Compounds that bind to isolated recombinant proteins are one thing; chemical tools that can perturb cell function another; and pharmacological agents that can be tolerated by a live organism and perturb its systems are yet another. If it were simple to ascertain the properties required to develop a lead discovered in vitro to one that is active in vivo, drug discovery would be as reliable as drug manufacturing.
In the past, the guinea pig was such a commonly used in vivo experimental subject that they became part of idiomatic English: "to be a guinea pig for someone/something". However, they have largely been replaced by smaller, cheaper, and faster breeding rats and mice. | In vivo
In vivo (Latin: within the living) means that which takes place inside an organism. In science, in vivo refers to experimentation done in or on the living tissue of a whole, living organism as opposed to a partial or dead one or a controlled environment. Animal testing and clinical trials are forms of in vivo research.
# in vivo research
This type of research approaches subject experimentation holistically. It is, often, better suited for observing the overall effects of an experiment on its living subject (see in vitro for its description and respective merits). In molecular biology "in vivo" may refer to experimentation done at the cellular level within the natural milieu of intact living cells. Once cells are disrupted and individual parts are tested or analyzed, this is known as "in vitro".
According to Christopher Lipinksi and Andrew Hopkins, fellows with Pfizer Global Research and Development, in vivo research has an advantage in that: Whether the aim is to discover drugs or to gain knowledge of biological systems, the nature and properties of a chemical tool cannot be considered independently of the system it is to be tested in. Compounds that bind to isolated recombinant proteins are one thing; chemical tools that can perturb cell function another; and pharmacological agents that can be tolerated by a live organism and perturb its systems are yet another. If it were simple to ascertain the properties required to develop a lead discovered in vitro to one that is active in vivo, drug discovery would be as reliable as drug manufacturing.[1]
In the past, the guinea pig was such a commonly used in vivo experimental subject that they became part of idiomatic English: "to be a guinea pig for someone/something". However, they have largely been replaced by smaller, cheaper, and faster breeding rats and mice. | https://www.wikidoc.org/index.php/In-vivo | |
84d6be4101375f3cd46723da99186c0a22f126dc | wikidoc | Inertia | Inertia
Inertia is the resistance an object has to a change in its state of motion. The principle of inertia is one of the fundamental principles of classical physics which are used to describe the motion of matter and how it is affected by applied forces. Sir Isaac Newton defined inertia in Definition 3 of his Philosophiæ Naturalis Principia Mathematica, which states:
The vis insita, or innate force of matter is a power of resisting, by which every body, as much as in it lies, endeavors to preserve in its present state, whether it be of rest, or of moving uniformly forward in a right line.
In common usage, however, people may also use the term "inertia" to refer to an object's "amount of resistance to change in velocity" (which is quantified by its mass), and sometimes its momentum, depending on context (e.g. "this object has a lot of inertia"). The term "inertia" is more properly understood as a shorthand for "the principle of inertia as described by Newton in Newton's First Law of Motion which, expressed simply, says: "An object that is not subject to any outside forces moves at a constant velocity, covering equal distances in equal times along a straight-line path." In even simpler terms, inertia means "A body in motion tends to remain in motion, a body at rest tends to remain at rest." On the surface of the Earth the nature of inertia is often masked by the effects of friction which brings moving objects to rest relatively quickly unless they are coasting on wheels, well lubricated or perhaps falling or going downhill, being accelerated by gravity. This is what misled classical theorists such as Aristotle who believed objects moved only so long as force was being applied to them.
# History and development of the concept
## Early understanding of motion
Prior to the Renaissance in the 15th century, the generally accepted theory of motion in Western philosophy was that proposed by Aristotle (around 335 BC to 322 BC), which stated that in the absence of an external motive power, all objects (on earth) would naturally come to rest in a state of no movement, and that moving objects only continue to move so long as there is a power inducing them to do so. Aristotle explained the continued motion of projectiles, which are separated from their projector, by the action of the surrounding medium which continues to move the projectile in some way. As a consequence, Aristotle concluded that such violent motion in a void was impossible for there would be nothing there to keep the body in motion against the resistance of its own gravity. Then in a statement regarded by Newton as expressing his Principia's first law of motion, Aristotle continued by asserting that a body in (non-violent) motion in a void would continue moving forever if externally unimpeded:
Despite its remarkable success and general acceptance, Aristotle's concept of motion was disputed on several occasions by notable philosophers over the nearly 2 millennia of its reign. For example, Lucretius (following, presumably, Epicurus) clearly stated that the 'default state' of matter was motion, not stasis. In the 6th century, John Philoponus criticized Aristotle's view, noting the inconsistency between Aristotle's discussion of projectiles, where the medium keeps projectiles going, and his discussion of the void, where the medium would hinder a body's motion. Philoponus proposed that motion was not maintained by the action of the surrounding medium but by some property implanted in the object when it was set in motion. This was not the modern concept of inertia, for there was still the need for a power to keep a body in motion. This view was strongly opposed by Averroes and many scholastic philosophers who supported Aristotle. However this view did not go unchallenged in the Islamic world, where Philoponus did have several supporters.
## Chinese theories
Mozi (Chinese: 墨子; pinyin: Mòzǐ; ca. 470 BCE–ca. 390 BCE), a philosopher who lived in China during the Hundred Schools of Thought period (early Warring States Period), composed or collected his thought in the book Mozi, which contains the following sentence: 'The cessation of motion is due to the opposing force ... If there is no opposing force ... the motion will never stop. This is as true as that an ox is not a horse.' which, according to Joseph Needham, is a precursor to Newton's first law of motion.
## Islamic theories
Several Muslim scientists from the medieval Islamic world wrote Arabic treatises on theories of motion. In the early 11th century, the Islamic scientist Ibn al-Haytham (Arabic:ابن الهيثم) (Latinized as Alhacen) hypothesized that an object will move perpetually unless a force causes it to stop or change direction. Alhacen's model of motion thus bears resemblance to the law of inertia (now known as Newton's first law of motion) later stated by Galileo Galilei in the 16th century.
Alhacen's contemporary, the Persian scientist Ibn Sina (Latinized as Avicenna), developed an elaborate theory of motion, in which he made a distinction between the inclination and force of a projectile, and concluded that motion was a result of an inclination (mayl) transferred to the projectile by the thrower, and that projectile motion in a vacuum would not cease. He viewed inclination as a permanent force whose effect is dissipated by external forces such as air resistance. Avicenna also referred to mayl to as being proportional to weight times velocity, which was similar to Newton's theory of momentum. Avicenna's concept of mayl was later used in Jean Buridan's theory of impetus.
Abū Rayhān al-Bīrūnī (973-1048) was the first physicist to realize that acceleration is connected with non-uniform motion. The first scientist to reject Aristotle's idea that a constant force produces uniform motion was the Arabic Muslim physicist and philosopher Hibat Allah Abu'l-Barakat al-Baghdaadi in the early 12th century. He was the first to argue that a force applied continuously produces acceleration, which is considered "the fundamental law of classical mechanics", and vaguely foreshadows Newton's second law of motion.
In the early 16th century, al-Birjandi, in his analysis on the Earth's rotation, developed a hypothesis similar to Galileo's notion of "circular inertia", which he described in the following observational test:
"The small or large rock will fall to the Earth along the path of a line that is perpendicular to the plane (sath) of the horizon; this is witnessed by experience (tajriba). And this perpendicular is away from the tangent point of the Earth’s sphere and the plane of the perceived (hissi) horizon. This point moves with the motion of the Earth and thus there will be no difference in place of fall of the two rocks."
## Theory of impetus
In the 14th century, Jean Buridan rejected the notion that a motion-generating property, which he named impetus, dissipated spontaneously. Buridan's position was that a moving object would be arrested by the resistance of the air and the weight of the body which would oppose its impetus. Buridan also maintained that impetus increased with speed; thus, his initial idea of impetus was similar in many ways to the modern concept of momentum. Despite the obvious similarities to more modern ideas of inertia, Buridan saw his theory as only a modification to Aristotle's basic philosophy, maintaining many other peripatetic views, including the belief that there was still a fundamental difference between an object in motion and an object at rest. Buridan also maintained that impetus could be not only linear, but also circular in nature, causing objects (such as celestial bodies) to move in a circle.
Buridan's thought was followed up by his pupil Albert of Saxony (1316-1390) and the Oxford Calculators, who performed various experiments that further undermined the classical, Aristotelian view. Their work in turn was elaborated by Nicole Oresme who pioneered the practice of demonstrating laws of motion in the form of graphs.
Shortly before Galileo's theory of inertia, Giambattista Benedetti modified the growing theory of impetus to involve linear motion alone:
"… portion of corporeal matter which moves by itself when an impetus has been impressed on it by any external motive force has a natural tendency to move on a rectilinear, not a curved, path."
Benedetti cites the motion of a rock in a sling as an example of the inherent linear motion of objects, forced into circular motion.
## Classical inertia
The law of inertia states that it is the tendency of an object to resist a change in motion.The Aristotelian division of motion into mundane and celestial became increasingly problematic in the face of the conclusions of Nicolaus Copernicus in the 16th century, who argued that the earth (and everything on it) was in fact never "at rest", but was actually in constant motion around the sun. Galileo, in his further development of the Copernican model, recognized these problems with the then-accepted nature of motion and, at least partially as a result, included a restatement of Aristotle's description of motion in a void as a basic physical principle:
A body moving on a level surface will continue in the same direction at a constant speed unless disturbed.
It is also worth nothing that Galileo later went on to conclude that based on this initial premise of inertia, it is impossible to tell the difference between a moving object and a stationary one without some outside reference to compare it against. This observation ultimately came to be the basis for Einstein to develop the theory of Special Relativity.
Galileo's concept of inertia would later come to be refined and codified by Isaac Newton as the first of his Laws of Motion (first published in Newton's work, Philosophiae Naturalis Principia Mathematica, in 1687):
Unless acted upon by an unbalanced force, an object will maintain a constant velocity.
Note that "velocity" in this context is defined as a vector, thus Newton's "constant velocity" implies both constant speed and constant direction (and also includes the case of zero speed, or no motion). Since initial publication, Newton's Laws of Motion (and by extension this first law) have come to form the basis for the almost universally accepted branch of physics now termed classical mechanics.
The actual term "inertia" was first introduced by Johannes Kepler in his Epitome Astronomiae Copernicanae (published in three parts from 1618-1621); however, the meaning of Kepler's term (which he derived from the Latin word for "idleness" or "laziness") was not quite the same as its modern interpretation. Kepler defined inertia only in terms of a resistance to movement, once again based on the presumption that rest was a natural state which did not need explanation. It was not until the later work of Galileo and Newton unified rest and motion in one principle that the term "inertia" could be applied to these concepts as it is today.
Nevertheless, despite defining the concept so elegantly in his laws of motion, even Newton did not actually use the term "inertia" to refer to his First Law. In fact, Newton originally viewed the phenomenon he described in his First Law of Motion as being caused by "innate forces" inherent in matter, which resisted any acceleration. Given this perspective, and borrowing from Kepler, Newton actually attributed the term "inertia" to mean "the innate force possessed by an object which resists changes in motion"; thus Newton defined "inertia" to mean the cause of the phenomenon, rather than the phenomenon itself. However, Newton's original ideas of "innate resistive force" were ultimately problematic for a variety of reasons, and thus most physicists no longer think in these terms. As no alternate mechanism has been readily accepted, and it is now generally accepted that there may not be one which we can know, the term "inertia" has come to mean simply the phenomenon itself, rather than any inherent mechanism. Thus, ultimately, "inertia" in modern classical physics has come to be a name for the same phenomenon described by Newton's First Law of Motion, and the two concepts are now basically equivalent.
## Relativity
Albert Einstein's theory of Special Relativity, as proposed in his 1905 paper, "On the Electrodynamics of Moving Bodies," was built on the understanding of inertia and inertial reference frames developed by Galileo and Newton. While this revolutionary theory did significantly change the meaning of many Newtonian concepts such as mass, energy, and distance, Einstein's concept of inertia remained unchanged from Newton's original meaning (in fact the entire theory was based on Newton's definition of inertia). However, this resulted in a limitation inherent in Special Relativity that it could only apply when reference frames were inertial in nature (meaning when no acceleration was present). In an attempt to address this limitation, Einstein proceeded to develop his theory of General Relativity ("The Foundation of the General Theory of Relativity," 1916), which ultimately provided a unified theory for both inertial and noninertial (accelerated) reference frames. However, in order to accomplish this, in General Relativity Einstein found it necessary to redefine several fundamental aspects of the universe (such as gravity) in terms of a new concept of "curvature" of spacetime, instead of the more traditional system of forces understood by Newton.
As a result of this redefinition, Einstein also redefined the concept of "inertia" in terms of geodesic deviation instead, with some subtle but significant additional implications. The result of this is that according to General Relativity, when dealing with very large scales, the traditional Newtonian idea of "inertia" does not actually apply, and cannot necessarily be relied upon. Luckily, for sufficiently small regions of spacetime, the Special Theory can still be used, in which inertia still means the same (and works the same) as in the classical model. Towards the end of his life it seems as if Einstein had become convinced that space-time is a new form of aether, in some way serving as a reference frame for the property of inertia.
Another profound, perhaps the most well-known, conclusion of the theory of Special Relativity was that energy and mass are not separate things, but are, in fact, interchangeable. This new relationship, however, also carried with it new implications for the concept of inertia. The logical conclusion of Special Relativity was that if mass exhibits the principle of inertia, then inertia must also apply to energy as well. This theory, and subsequent experiments confirming some of its conclusions, have also served to radically expand the definition of inertia in some contexts to apply to a much wider context including energy as well as matter.
# Interpretations
## According to Isaac Asimov
According to Isaac Asimov in "Understanding Physics": "This tendency for motion (or for rest) to maintain itself steadily unless made to do otherwise by some interfering force can be viewed as a kind of "laziness," a kind of unwillingness to make a change. And indeed, Newton's first law of motion
as Isaac Asimov goes on to explain, "Newton's laws of motion represent assumptions and definitions and are not subject to proof. In particular, the notion of 'inertia' is as much an assumption as Aristotle's notion of 'natural place.'...To be sure, the new relativistic view of the universe advanced by Einstein makes it plain that in some respects Newton's laws of motion are only approximations...At ordinary velocities and distance, however, the approximations are extremely good."
## Mass and 'inertia'
Physics and mathematics appear to be less inclined to use the original concept of inertia as "a tendency to maintain momentum" and instead favor the mathematically useful definition of inertia as the measure of a body's resistance to changes in momentum or simply a body's inertial mass.
This was clear in the beginning of the 20th century, when the theory of relativity was not yet created. Mass, m, denoted something like amount of substance or quantity of matter. And at the same time mass was the quantitative measure of inertia of a body.
The mass of a body determines the momentum P of the body at given velocity v; it is a proportionality factor in the formula:
The factor m is referred to as inertial mass.
But mass as related to 'inertia' of a body can be defined also by the formula:
By this formula, the greater its mass, the less a body accelerates under given force. Masses m defined by the formula (1) and (2) are equal because the formula (2) is a consequence of the formula (1) if mass does not depend on time and speed. Thus, "mass is the quantitative or numerical measure of body’s inertia, that is of its resistance to being accelerated".
This meaning of a body's inertia therefore is altered from the original meaning as "a tendency to maintain momentum" to a description of the measure of how difficult it is to change the momentum of a body.
## Inertial mass
The only difference there appears to be between inertial mass and gravitational mass is the method used to determine them.
Gravitational mass is measured by comparing the force of gravity of an unknown mass to the force of gravity of a known mass. This is typically done with some sort of balance scale. The beauty of this method is that no matter where, or on what planet you are, the masses will always balance out because the gravitational acceleration on each object will be the same. This does break down near supermassive objects such as black holes and neutron stars due to the high gradient of the gravitational field around such objects.
Inertial mass is found by applying a known force to an unknown mass, measuring the acceleration, and applying Newton's Second Law, m = F/a. This gives an accurate value for mass, limited only by the accuracy of the measurements. When astronauts need to be weighed in outer space, they actually find their inertial mass in a special chair.
The interesting thing is that, physically, no difference has been found between gravitational and inertial mass. Many experiments have been performed to check the values and the experiments always agree to within the margin of error for the experiment. Einstein used the fact that gravitational and inertial mass were equal to begin his Theory of General Relativity in which he postulated that gravitational mass was the same as inertial mass, and that the acceleration of gravity is a result of a 'valley' or slope in the space-time continuum that masses 'fell down' much as pennies spiral around a hole in the common donation toy at a chain store.
Since Einstein used inertial mass to describe Special Relativity, inertial mass is closely related to relativistic mass and is therefore different from rest mass.
## Inertial frames
In a location such as a steadily moving railway carriage, a dropped ball (as seen by an observer in the carriage) would behave as it would if it were dropped in a stationary carriage. The ball would simply descend vertically. It is possible to ignore the motion of the carriage by defining it as an inertial frame. In a moving but non-accelerating frame, the ball behaves normally because the train and its contents continue to move at a constant velocity. Before being dropped, the ball was traveling with the train at the same speed, and the ball's inertia ensured that it continued to move in the same speed and direction as the train, even while dropping. Note that, here, it is inertia which ensured that, not its mass.
In an inertial frame all the observers in uniform (non-accelerating) motion will observe the same laws of physics. However observers in another inertial frame can make a simple, and intuitively obvious, transformation (the Galilean transformation), to convert their observations. Thus, an observer from outside the moving train could deduce that the dropped ball within the carriage fell vertically downwards.
However, in frames which are experiencing acceleration (non-inertial frames), objects appear to be affected by fictitious forces. For example, if the railway carriage was accelerating, the ball would not fall vertically within the carriage but would appear to an observer to be deflected because the carriage and the ball would not be traveling at the same speed while the ball was falling. Other examples of fictitious forces occur in rotating frames such as the earth. For example, a missile at the North Pole could be aimed directly at a location and fired southwards. An observer would see it apparently deflected away from its target by a force (the Coriolis force) but in reality the southerly target has moved because earth has rotated while the missile is in flight. Because the earth is rotating, a useful inertial frame of reference is defined by the stars, which only move imperceptibly during most observations.
In summary, the principle of inertia is intimately linked with the principles of conservation of energy and conservation of momentum.
# Rotational inertia
Another form of inertia is rotational inertia (→ moment of inertia), which refers to the fact that a rotating rigid body maintains its state of uniform rotational motion. Its angular momentum is unchanged, unless an external torque is applied; this is also called conservation of angular momentum. Rotational inertia often has hidden practical consequences. | Inertia
Template:Otheruses1
Inertia is the resistance an object has to a change in its state of motion. The principle of inertia is one of the fundamental principles of classical physics which are used to describe the motion of matter and how it is affected by applied forces. Sir Isaac Newton defined inertia in Definition 3 of his Philosophiæ Naturalis Principia Mathematica, which states:[1]
The vis insita, or innate force of matter is a power of resisting, by which every body, as much as in it lies, endeavors to preserve in its present state, whether it be of rest, or of moving uniformly forward in a right line.
In common usage, however, people may also use the term "inertia" to refer to an object's "amount of resistance to change in velocity" (which is quantified by its mass), and sometimes its momentum, depending on context (e.g. "this object has a lot of inertia"). The term "inertia" is more properly understood as a shorthand for "the principle of inertia as described by Newton in Newton's First Law of Motion which, expressed simply, says: "An object that is not subject to any outside forces moves at a constant velocity, covering equal distances in equal times along a straight-line path." In even simpler terms, inertia means "A body in motion tends to remain in motion, a body at rest tends to remain at rest." On the surface of the Earth the nature of inertia is often masked by the effects of friction which brings moving objects to rest relatively quickly unless they are coasting on wheels, well lubricated or perhaps falling or going downhill, being accelerated by gravity. This is what misled classical theorists such as Aristotle who believed objects moved only so long as force was being applied to them.[2]
# History and development of the concept
## Early understanding of motion
Prior to the Renaissance in the 15th century, the generally accepted theory of motion in Western philosophy was that proposed by Aristotle (around 335 BC to 322 BC), which stated that in the absence of an external motive power, all objects (on earth) would naturally come to rest in a state of no movement, and that moving objects only continue to move so long as there is a power inducing them to do so. Aristotle explained the continued motion of projectiles, which are separated from their projector, by the action of the surrounding medium which continues to move the projectile in some way.[3] As a consequence, Aristotle concluded that such violent motion in a void was impossible for there would be nothing there to keep the body in motion against the resistance of its own gravity.[4] Then in a statement regarded by Newton as expressing his Principia's first law of motion, Aristotle continued by asserting that a body in (non-violent) motion in a void would continue moving forever if externally unimpeded:
Despite its remarkable success and general acceptance, Aristotle's concept of motion was disputed on several occasions by notable philosophers over the nearly 2 millennia of its reign. For example, Lucretius (following, presumably, Epicurus) clearly stated that the 'default state' of matter was motion, not stasis.[6] In the 6th century, John Philoponus criticized Aristotle's view, noting the inconsistency between Aristotle's discussion of projectiles, where the medium keeps projectiles going, and his discussion of the void, where the medium would hinder a body's motion. Philoponus proposed that motion was not maintained by the action of the surrounding medium but by some property implanted in the object when it was set in motion. This was not the modern concept of inertia, for there was still the need for a power to keep a body in motion.[7] This view was strongly opposed by Averroes and many scholastic philosophers who supported Aristotle. However this view did not go unchallenged in the Islamic world, where Philoponus did have several supporters.
## Chinese theories
Mozi (Chinese: 墨子; pinyin: Mòzǐ; ca. 470 BCE–ca. 390 BCE), a philosopher who lived in China during the Hundred Schools of Thought period (early Warring States Period), composed or collected his thought in the book Mozi, which contains the following sentence: 'The cessation of motion is due to the opposing force ... If there is no opposing force ... the motion will never stop. This is as true as that an ox is not a horse.' which, according to Joseph Needham, is a precursor to Newton's first law of motion.
## Islamic theories
Several Muslim scientists from the medieval Islamic world wrote Arabic treatises on theories of motion. In the early 11th century, the Islamic scientist Ibn al-Haytham (Arabic:ابن الهيثم) (Latinized as Alhacen) hypothesized that an object will move perpetually unless a force causes it to stop or change direction. Alhacen's model of motion thus bears resemblance to the law of inertia (now known as Newton's first law of motion) later stated by Galileo Galilei in the 16th century.[8]
Alhacen's contemporary, the Persian scientist Ibn Sina (Latinized as Avicenna), developed an elaborate theory of motion, in which he made a distinction between the inclination and force of a projectile, and concluded that motion was a result of an inclination (mayl) transferred to the projectile by the thrower, and that projectile motion in a vacuum would not cease.[9] He viewed inclination as a permanent force whose effect is dissipated by external forces such as air resistance.[10] [9] Avicenna also referred to mayl to as being proportional to weight times velocity, which was similar to Newton's theory of momentum.[11] Avicenna's concept of mayl was later used in Jean Buridan's theory of impetus.
Abū Rayhān al-Bīrūnī (973-1048) was the first physicist to realize that acceleration is connected with non-uniform motion.[12] The first scientist to reject Aristotle's idea that a constant force produces uniform motion was the Arabic Muslim physicist and philosopher Hibat Allah Abu'l-Barakat al-Baghdaadi in the early 12th century. He was the first to argue that a force applied continuously produces acceleration, which is considered "the fundamental law of classical mechanics",[13] and vaguely foreshadows Newton's second law of motion.
In the early 16th century, al-Birjandi, in his analysis on the Earth's rotation, developed a hypothesis similar to Galileo's notion of "circular inertia",[14] which he described in the following observational test:
"The small or large rock will fall to the Earth along the path of a line that is perpendicular to the plane (sath) of the horizon; this is witnessed by experience (tajriba). And this perpendicular is away from the tangent point of the Earth’s sphere and the plane of the perceived (hissi) horizon. This point moves with the motion of the Earth and thus there will be no difference in place of fall of the two rocks."[15]
## Theory of impetus
Template:Seealso
In the 14th century, Jean Buridan rejected the notion that a motion-generating property, which he named impetus, dissipated spontaneously. Buridan's position was that a moving object would be arrested by the resistance of the air and the weight of the body which would oppose its impetus.[16] Buridan also maintained that impetus increased with speed; thus, his initial idea of impetus was similar in many ways to the modern concept of momentum. Despite the obvious similarities to more modern ideas of inertia, Buridan saw his theory as only a modification to Aristotle's basic philosophy, maintaining many other peripatetic views, including the belief that there was still a fundamental difference between an object in motion and an object at rest. Buridan also maintained that impetus could be not only linear, but also circular in nature, causing objects (such as celestial bodies) to move in a circle.
Buridan's thought was followed up by his pupil Albert of Saxony (1316-1390) and the Oxford Calculators, who performed various experiments that further undermined the classical, Aristotelian view. Their work in turn was elaborated by Nicole Oresme who pioneered the practice of demonstrating laws of motion in the form of graphs.
Shortly before Galileo's theory of inertia, Giambattista Benedetti modified the growing theory of impetus to involve linear motion alone:
"…[Any] portion of corporeal matter which moves by itself when an impetus has been impressed on it by any external motive force has a natural tendency to move on a rectilinear, not a curved, path."[17]
Benedetti cites the motion of a rock in a sling as an example of the inherent linear motion of objects, forced into circular motion.
## Classical inertia
The law of inertia states that it is the tendency of an object to resist a change in motion.The Aristotelian division of motion into mundane and celestial became increasingly problematic in the face of the conclusions of Nicolaus Copernicus in the 16th century, who argued that the earth (and everything on it) was in fact never "at rest", but was actually in constant motion around the sun.[18] Galileo, in his further development of the Copernican model, recognized these problems with the then-accepted nature of motion and, at least partially as a result, included a restatement of Aristotle's description of motion in a void as a basic physical principle:
A body moving on a level surface will continue in the same direction at a constant speed unless disturbed.
It is also worth nothing that Galileo later went on to conclude that based on this initial premise of inertia, it is impossible to tell the difference between a moving object and a stationary one without some outside reference to compare it against.[19] This observation ultimately came to be the basis for Einstein to develop the theory of Special Relativity.
Galileo's concept of inertia would later come to be refined and codified by Isaac Newton as the first of his Laws of Motion (first published in Newton's work, Philosophiae Naturalis Principia Mathematica, in 1687):
Unless acted upon by an unbalanced force, an object will maintain a constant velocity.
Note that "velocity" in this context is defined as a vector, thus Newton's "constant velocity" implies both constant speed and constant direction (and also includes the case of zero speed, or no motion). Since initial publication, Newton's Laws of Motion (and by extension this first law) have come to form the basis for the almost universally accepted branch of physics now termed classical mechanics.
The actual term "inertia" was first introduced by Johannes Kepler in his Epitome Astronomiae Copernicanae (published in three parts from 1618-1621); however, the meaning of Kepler's term (which he derived from the Latin word for "idleness" or "laziness") was not quite the same as its modern interpretation. Kepler defined inertia only in terms of a resistance to movement, once again based on the presumption that rest was a natural state which did not need explanation. It was not until the later work of Galileo and Newton unified rest and motion in one principle that the term "inertia" could be applied to these concepts as it is today.
Nevertheless, despite defining the concept so elegantly in his laws of motion, even Newton did not actually use the term "inertia" to refer to his First Law. In fact, Newton originally viewed the phenomenon he described in his First Law of Motion as being caused by "innate forces" inherent in matter, which resisted any acceleration. Given this perspective, and borrowing from Kepler, Newton actually attributed the term "inertia" to mean "the innate force possessed by an object which resists changes in motion"; thus Newton defined "inertia" to mean the cause of the phenomenon, rather than the phenomenon itself. However, Newton's original ideas of "innate resistive force" were ultimately problematic for a variety of reasons, and thus most physicists no longer think in these terms. As no alternate mechanism has been readily accepted, and it is now generally accepted that there may not be one which we can know, the term "inertia" has come to mean simply the phenomenon itself, rather than any inherent mechanism. Thus, ultimately, "inertia" in modern classical physics has come to be a name for the same phenomenon described by Newton's First Law of Motion, and the two concepts are now basically equivalent.
## Relativity
Albert Einstein's theory of Special Relativity, as proposed in his 1905 paper, "On the Electrodynamics of Moving Bodies," was built on the understanding of inertia and inertial reference frames developed by Galileo and Newton. While this revolutionary theory did significantly change the meaning of many Newtonian concepts such as mass, energy, and distance, Einstein's concept of inertia remained unchanged from Newton's original meaning (in fact the entire theory was based on Newton's definition of inertia). However, this resulted in a limitation inherent in Special Relativity that it could only apply when reference frames were inertial in nature (meaning when no acceleration was present). In an attempt to address this limitation, Einstein proceeded to develop his theory of General Relativity ("The Foundation of the General Theory of Relativity," 1916), which ultimately provided a unified theory for both inertial and noninertial (accelerated) reference frames. However, in order to accomplish this, in General Relativity Einstein found it necessary to redefine several fundamental aspects of the universe (such as gravity) in terms of a new concept of "curvature" of spacetime, instead of the more traditional system of forces understood by Newton.
As a result of this redefinition, Einstein also redefined the concept of "inertia" in terms of geodesic deviation instead, with some subtle but significant additional implications. The result of this is that according to General Relativity, when dealing with very large scales, the traditional Newtonian idea of "inertia" does not actually apply, and cannot necessarily be relied upon. Luckily, for sufficiently small regions of spacetime, the Special Theory can still be used, in which inertia still means the same (and works the same) as in the classical model. Towards the end of his life it seems as if Einstein had become convinced that space-time is a new form of aether, in some way serving as a reference frame for the property of inertia[20].
Another profound, perhaps the most well-known, conclusion of the theory of Special Relativity was that energy and mass are not separate things, but are, in fact, interchangeable. This new relationship, however, also carried with it new implications for the concept of inertia. The logical conclusion of Special Relativity was that if mass exhibits the principle of inertia, then inertia must also apply to energy as well. This theory, and subsequent experiments confirming some of its conclusions, have also served to radically expand the definition of inertia in some contexts to apply to a much wider context including energy as well as matter.
# Interpretations
## According to Isaac Asimov
According to Isaac Asimov in "Understanding Physics": "This tendency for motion (or for rest) to maintain itself steadily unless made to do otherwise by some interfering force can be viewed as a kind of "laziness," a kind of unwillingness to make a change. And indeed, Newton's first law of motion
as Isaac Asimov goes on to explain, "Newton's laws of motion represent assumptions and definitions and are not subject to proof. In particular, the notion of 'inertia' is as much an assumption as Aristotle's notion of 'natural place.'...To be sure, the new relativistic view of the universe advanced by Einstein makes it plain that in some respects Newton's laws of motion are only approximations...At ordinary velocities and distance, however, the approximations are extremely good."
## Mass and 'inertia'
Physics and mathematics appear to be less inclined to use the original concept of inertia as "a tendency to maintain momentum" and instead favor the mathematically useful definition of inertia as the measure of a body's resistance to changes in momentum or simply a body's inertial mass.
This was clear in the beginning of the 20th century, when the theory of relativity was not yet created. Mass, m, denoted something like amount of substance or quantity of matter. And at the same time mass was the quantitative measure of inertia of a body.
The mass of a body determines the momentum P of the body at given velocity v; it is a proportionality factor in the formula:
The factor m is referred to as inertial mass.
But mass as related to 'inertia' of a body can be defined also by the formula:
By this formula, the greater its mass, the less a body accelerates under given force. Masses m defined by the formula (1) and (2) are equal because the formula (2) is a consequence of the formula (1) if mass does not depend on time and speed. Thus, "mass is the quantitative or numerical measure of body’s inertia, that is of its resistance to being accelerated".
This meaning of a body's inertia therefore is altered from the original meaning as "a tendency to maintain momentum" to a description of the measure of how difficult it is to change the momentum of a body.
## Inertial mass
The only difference there appears to be between inertial mass and gravitational mass is the method used to determine them.
Gravitational mass is measured by comparing the force of gravity of an unknown mass to the force of gravity of a known mass. This is typically done with some sort of balance scale. The beauty of this method is that no matter where, or on what planet you are, the masses will always balance out because the gravitational acceleration on each object will be the same. This does break down near supermassive objects such as black holes and neutron stars due to the high gradient of the gravitational field around such objects.
Inertial mass is found by applying a known force to an unknown mass, measuring the acceleration, and applying Newton's Second Law, m = F/a. This gives an accurate value for mass, limited only by the accuracy of the measurements. When astronauts need to be weighed in outer space, they actually find their inertial mass in a special chair.
The interesting thing is that, physically, no difference has been found between gravitational and inertial mass. Many experiments have been performed to check the values and the experiments always agree to within the margin of error for the experiment. Einstein used the fact that gravitational and inertial mass were equal to begin his Theory of General Relativity in which he postulated that gravitational mass was the same as inertial mass, and that the acceleration of gravity is a result of a 'valley' or slope in the space-time continuum that masses 'fell down' much as pennies spiral around a hole in the common donation toy at a chain store.
Since Einstein used inertial mass to describe Special Relativity, inertial mass is closely related to relativistic mass and is therefore different from rest mass.
## Inertial frames
In a location such as a steadily moving railway carriage, a dropped ball (as seen by an observer in the carriage) would behave as it would if it were dropped in a stationary carriage. The ball would simply descend vertically. It is possible to ignore the motion of the carriage by defining it as an inertial frame. In a moving but non-accelerating frame, the ball behaves normally because the train and its contents continue to move at a constant velocity. Before being dropped, the ball was traveling with the train at the same speed, and the ball's inertia ensured that it continued to move in the same speed and direction as the train, even while dropping. Note that, here, it is inertia which ensured that, not its mass.
In an inertial frame all the observers in uniform (non-accelerating) motion will observe the same laws of physics. However observers in another inertial frame can make a simple, and intuitively obvious, transformation (the Galilean transformation), to convert their observations. Thus, an observer from outside the moving train could deduce that the dropped ball within the carriage fell vertically downwards.
However, in frames which are experiencing acceleration (non-inertial frames), objects appear to be affected by fictitious forces. For example, if the railway carriage was accelerating, the ball would not fall vertically within the carriage but would appear to an observer to be deflected because the carriage and the ball would not be traveling at the same speed while the ball was falling. Other examples of fictitious forces occur in rotating frames such as the earth. For example, a missile at the North Pole could be aimed directly at a location and fired southwards. An observer would see it apparently deflected away from its target by a force (the Coriolis force) but in reality the southerly target has moved because earth has rotated while the missile is in flight. Because the earth is rotating, a useful inertial frame of reference is defined by the stars, which only move imperceptibly during most observations.
In summary, the principle of inertia is intimately linked with the principles of conservation of energy and conservation of momentum.
# Rotational inertia
Another form of inertia is rotational inertia (→ moment of inertia), which refers to the fact that a rotating rigid body maintains its state of uniform rotational motion. Its angular momentum is unchanged, unless an external torque is applied; this is also called conservation of angular momentum. Rotational inertia often has hidden practical consequences. | https://www.wikidoc.org/index.php/Inertia | |
72f954ce642c4674ef50fae0efcabe49dabada49 | wikidoc | Infobox | Infobox
An infobox on Wikipedia is a consistently-formatted table which is present in articles with a common subject to provide summary information consistently between articles or improve navigation to closely related articles in that subject. (An infobox is a generalization of a taxobox (from taxonomy) which summarizes information for an organism or group of organisms.)
If you make an infobox for a new project, it should be placed on the Wikipedia:List of infoboxes/Proposed sub-page when it is proposed and moved to the appropriate sub-page of the main list when it has been implemented. If you choose to use colors in your table, please do not choose one that is already being used, and place your choice on this list so that others know it has been taken. You can use either the same color for all tables in a project, or use a system of coloration (for example, the organism taxobox has different colors for each of the kingdoms). To find more information about what colors can be used, see the article on web colors.
If you want to redesign an Infobox, please take it up with the appropriate WikiProject.
An infobox may or may not use the template software feature. Infobox templates are an alternative to static infoboxes; they can be used to create a common look between subject items, with a minimum of coding within articles. See also Wikipedia:Infobox templates.
If your infobox is aligned right, please consider having it no wider than 1/3 the width of the available page.
# Basic Infobox
The basic template pattern can be found at Template:Infobox. This basic template includes the use of optional parameters, compare Wikipedia:Qif conditionals.
# Taxobox Example
This is an example of a taxobox. See Wikipedia:WikiProject Tree of Life/taxobox usage for full instructions. | Infobox
Template:See Also
An infobox on Wikipedia is a consistently-formatted table which is present in articles with a common subject to provide summary information consistently between articles or improve navigation to closely related articles in that subject. (An infobox is a generalization of a taxobox (from taxonomy) which summarizes information for an organism or group of organisms.)
If you make an infobox for a new project, it should be placed on the Wikipedia:List of infoboxes/Proposed sub-page when it is proposed and moved to the appropriate sub-page of the main list when it has been implemented. If you choose to use colors in your table, please do not choose one that is already being used, and place your choice on this list so that others know it has been taken. You can use either the same color for all tables in a project, or use a system of coloration (for example, the organism taxobox has different colors for each of the kingdoms). To find more information about what colors can be used, see the article on web colors.
If you want to redesign an Infobox, please take it up with the appropriate WikiProject.
An infobox may or may not use the template software feature. Infobox templates are an alternative to static infoboxes; they can be used to create a common look between subject items, with a minimum of coding within articles. See also Wikipedia:Infobox templates.
If your infobox is aligned right, please consider having it no wider than 1/3 the width of the available page.
# Basic Infobox
The basic template pattern can be found at Template:Infobox. This basic template includes the use of optional parameters, compare Wikipedia:Qif conditionals.
# Taxobox Example
This is an example of a taxobox. See Wikipedia:WikiProject Tree of Life/taxobox usage for full instructions. | https://www.wikidoc.org/index.php/Infobox | |
f0348c9aa93cacce33529f8675e111ecf9e13c24 | wikidoc | Inhaler | Inhaler
# Overview
An inhaler or puffer is a medical device used for delivering medication into the body via the lungs. It is mainly used in the treatment of asthma and Chronic Obstructive Pulmonary Disease (COPD).
Medication is most commonly stored in solution in a pressurized canister. The canister is attached to a plastic, hand-operated actuator. For example, the metered-dose inhaler (MDI) on activation releases a fixed dose of medication in aerosol form. The correct procedure for using a MDI is to first fully exhale, place the mouth-piece end of the pump into the mouth, and having just started to inhale, depress the canister to release the medicine. The aerosolized medication is drawn into the lungs by continuing to inhale deeply before holding the breath for 10 seconds to allow absorption into the bronchial walls.
Alternatively a complementary spacer devise may be used, of which is an enclosed plastic chamber that mixes the medication with air in a simple tube, making it easier for patients to receive a full dose of the drug.
The largest manufacturers of inhalers are GlaxoSmithKline (makers of the Advair Discus (a DPI)), Merck, AstraZeneca (makers of Pulmicort and Symbicort) and Boehringer-Ingelheim (makers of Atrovent, Combivent, and Spiriva). BI, GSK, Merck, and AstraZeneca manufacture the medication being delivered via inhaler. However, 3M Drug Delivery Systems does some of the finished product manufacturing, as they are one of the leaders of MDI canisters, metering valves and other components.
# Current Types of Inhalers by Delivery
- Metered-dose inhaler or MDI
- Dry Powder Inhaler or DPI
- Nebulizer
# Current Types of Inhalers by Category
- Rescue Inhalers: Short-Acting Beta-2 Adrenergic Bronchodilator Inhalers
- Maintenance Inhalers: Long-Acting Adrenergic Bronchodilator Inhalers
- Maintenance Inhalers: Anticholinergic Bronchodilators in COPD
- Maintenance Inhalers: Corticosteroids
- Combination Inhalers: Corticosteroid with LongActing Beta-2 Adrenergic Agonist
- Combination Maintenance Inhaler: Anticholinergics with Short- Acting Beta-2 Adrenergic Agonists | Inhaler
# Overview
An inhaler or puffer is a medical device used for delivering medication into the body via the lungs. It is mainly used in the treatment of asthma and Chronic Obstructive Pulmonary Disease (COPD).
Medication is most commonly stored in solution in a pressurized canister. The canister is attached to a plastic, hand-operated actuator. For example, the metered-dose inhaler (MDI) on activation releases a fixed dose of medication in aerosol form. The correct procedure for using a MDI is to first fully exhale, place the mouth-piece end of the pump into the mouth, and having just started to inhale, depress the canister to release the medicine. The aerosolized medication is drawn into the lungs by continuing to inhale deeply before holding the breath for 10 seconds to allow absorption into the bronchial walls.
Alternatively a complementary spacer devise may be used, of which is an enclosed plastic chamber that mixes the medication with air in a simple tube, making it easier for patients to receive a full dose of the drug.
The largest manufacturers of inhalers are GlaxoSmithKline (makers of the Advair Discus (a DPI)), Merck, AstraZeneca (makers of Pulmicort and Symbicort) and Boehringer-Ingelheim (makers of Atrovent, Combivent, and Spiriva). BI, GSK, Merck, and AstraZeneca manufacture the medication being delivered via inhaler. However, 3M Drug Delivery Systems does some of the finished product manufacturing, as they are one of the leaders of MDI canisters, metering valves and other components.
# Current Types of Inhalers by Delivery
- Metered-dose inhaler or MDI
- Dry Powder Inhaler or DPI
- Nebulizer
# Current Types of Inhalers by Category
- Rescue Inhalers: Short-Acting Beta-2 Adrenergic Bronchodilator Inhalers
- Maintenance Inhalers: Long-Acting Adrenergic Bronchodilator Inhalers
- Maintenance Inhalers: Anticholinergic Bronchodilators in COPD
- Maintenance Inhalers: Corticosteroids
- Combination Inhalers: Corticosteroid with LongActing Beta-2 Adrenergic Agonist
- Combination Maintenance Inhaler: Anticholinergics with Short- Acting Beta-2 Adrenergic Agonists[1] | https://www.wikidoc.org/index.php/Inhaler | |
f29ef093b2ef60a9e124562e67f397cceb1fd2bd | wikidoc | Inhibin | Inhibin
# Overview
Inhibin is a peptide that is an inhibitor of FSH synthesis and secretion, and participates in the regulation of the menstrual cycle.
# Structure
Inhibin contains an alpha and beta subunit linked by disulfide bonds. Two forms of inhibin differ in their beta subunits (A or B), while their alpha subunits are identical.
Inhibin belongs to the transforming growth factor-β (TGF-β) superfamily.
# Action
## In women
In women, FSH stimulates the secretion of inhibin from the granulosa cells of the ovarian follicles in ovary. In turn, inhibin suppresses FSH.
Inhibin secretion is diminished by GnRH, and enhanced by insulin-like growth factor-1 (IGF-1).
- Inhibin B reaches a peak in the early- to mid-follicular phase, and a second peak at ovulation.
- Inhibin A reaches its peak in the mid-luteal phase.
Inhibin is produced in the gonads, pituitary gland, placenta and other organs.
## In men
In men, it is a hormone that inhibits FSH production.
It is secreted from the Sertoli cells, located in the seminiferous tubule inside the testes.
# Activin
Activin is a related peptide that counteracts inhibin.
# Clinical significance
Quantification of inhibin A is part of the prenatal quad screen that can be administered during pregnancy at a gestational age of 16-18 weeks. An elevated inhibin A (along with an increased beta-hCG, decreased AFP, and a decreased estriol) is suggestive of the presence of a fetus with Down's syndrome. As a screening test, abnormal quad screen test results need to be followed up with more definitive tests.
It also has been used as a marker for ovarian cancer. | Inhibin
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-632-7753
# Overview
Inhibin is a peptide that is an inhibitor of FSH synthesis and secretion,[1] and participates in the regulation of the menstrual cycle.
# Structure
Inhibin contains an alpha and beta subunit linked by disulfide bonds. Two forms of inhibin differ in their beta subunits (A or B), while their alpha subunits are identical.
Inhibin belongs to the transforming growth factor-β (TGF-β) superfamily.
# Action
## In women
In women, FSH stimulates the secretion of inhibin from the granulosa cells of the ovarian follicles in ovary. In turn, inhibin suppresses FSH.
Inhibin secretion is diminished by GnRH, and enhanced by insulin-like growth factor-1 (IGF-1).
- Inhibin B reaches a peak in the early- to mid-follicular phase, and a second peak at ovulation.
- Inhibin A reaches its peak in the mid-luteal phase.
Inhibin is produced in the gonads, pituitary gland, placenta and other organs.
## In men
In men, it is a hormone that inhibits FSH production.
It is secreted from the Sertoli cells,[2] located in the seminiferous tubule inside the testes.
# Activin
Activin is a related peptide that counteracts inhibin.
# Clinical significance
Quantification of inhibin A is part of the prenatal quad screen that can be administered during pregnancy at a gestational age of 16-18 weeks. An elevated inhibin A (along with an increased beta-hCG, decreased AFP, and a decreased estriol) is [3] suggestive of the presence of a fetus with Down's syndrome. As a screening test, abnormal quad screen test results need to be followed up with more definitive tests.
It also has been used as a marker for ovarian cancer.[4][5] | https://www.wikidoc.org/index.php/Inhibin | |
f04aa3ee54cdb4fdd8607b8ce0f7e736620a29d2 | wikidoc | Inocybe | Inocybe
Inocybe is a large, complex genus of mushrooms. Members of Inocybe are mycorrhizal, and some evidence shows that the high degree of speciation in the genus is due to adaptation to different trees and perhaps even local environments.
Typical mushrooms of the genus are any of various shades of brown, although some lilac or purplish species exist. Caps are small and conical, though flattening somewhat in age, generally with a pronounced raised central knob. The cap often appears fibrous or frayed, giving the genus its common name of "fiber caps". Many species have a distinctive odor, various described as musty or spermatic.
Inocybe species are not considered suitable for consumption. Many species contain large doses of muscarine, and no easy method of distinguishing them from potentially edible species exists. In fact, Inocybe is the most commonly-encountered mushroom genus for which microscopic characteristics are the only means of certain identification to the species level. Seven species of Inocybe are hallucinogenic, having been found to contain psilocybin including Inocybe aeruginascens which also contains aeruginascine. (N, N, N-trimethyl-4-phosphoryloxytryptamine)
There are hundreds of species of Inocybe and a complete listing here is infeasible. Representatives of the genus include:
- Inocybe adaequata
- Inocybe aeruginascens (psychoactive)
- Inocybe coelestium (psychoactive)
- Inocybe corydalina Quél. var. corydalina (psychoactive)
- Inocybe corydalina var. erinaceomorpha (psychoactive)
- Inocybe geophylla
- Inocybe haemacta (psychoactive)
- Inocybe hystrix
- Inocybe lacera
- Inocybe obscura
- Inocybe rimosa
- Inocybe patouillardii
- Inocybe sororia
- Inocybe tricolor (psychoactive)
- Inocybe violaceocaulis. (prev. I. geophylla var. lilacina) In Western Australia, what represents I. violaceocaulis was earlier referred to as I. geophylla var. lilacina by some Australian taxonomists, which Matheny & Bougher (2005) point to as a misapplication of the name I. geophylla var. lilacina.
# Footnotes
- ↑ Matheny PB, Bougher NL (2004). "A new violet species of Inocybe (Agaricales) from Urban and Rural Landscapes in Western Australia". Australasian Mycologist. 24 (1)..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}
in certain countries inocybe mushroomes are consumed as food:papua new guinea and other under developed countries,increasing the sevirity of edible species in the inocybe genus. | Inocybe
Inocybe is a large, complex genus of mushrooms. Members of Inocybe are mycorrhizal, and some evidence shows that the high degree of speciation in the genus is due to adaptation to different trees and perhaps even local environments.
Typical mushrooms of the genus are any of various shades of brown, although some lilac or purplish species exist. Caps are small and conical, though flattening somewhat in age, generally with a pronounced raised central knob. The cap often appears fibrous or frayed, giving the genus its common name of "fiber caps". Many species have a distinctive odor, various described as musty or spermatic.
Inocybe species are not considered suitable for consumption. Many species contain large doses of muscarine, and no easy method of distinguishing them from potentially edible species exists. In fact, Inocybe is the most commonly-encountered mushroom genus for which microscopic characteristics are the only means of certain identification to the species level. Seven species of Inocybe are hallucinogenic, [1] having been found to contain psilocybin including Inocybe aeruginascens which also contains aeruginascine. (N, N, N-trimethyl-4-phosphoryloxytryptamine)
There are hundreds of species of Inocybe and a complete listing here is infeasible. Representatives of the genus include:
- Inocybe adaequata
- Inocybe aeruginascens (psychoactive)
- Inocybe coelestium (psychoactive)
- Inocybe corydalina Quél. var. corydalina (psychoactive)
- Inocybe corydalina var. erinaceomorpha (psychoactive)
- Inocybe geophylla
- Inocybe haemacta (psychoactive)
- Inocybe hystrix
- Inocybe lacera
- Inocybe obscura
- Inocybe rimosa
- Inocybe patouillardii
- Inocybe sororia
- Inocybe tricolor (psychoactive)
- Inocybe violaceocaulis[2]. (prev. I. geophylla var. lilacina) In Western Australia, what represents I. violaceocaulis was earlier referred to as I. geophylla var. lilacina by some Australian taxonomists, which Matheny & Bougher (2005) point to as a misapplication of the name I. geophylla var. lilacina.
# Footnotes
- ↑ http://www.museocivico.rovereto.tn.it/UploadDocs/104_art09-Guzman%20&%20C.pdf
- ↑ Matheny PB, Bougher NL (2004). "A new violet species of Inocybe (Agaricales) from Urban and Rural Landscapes in Western Australia". Australasian Mycologist. 24 (1)..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}
in certain countries inocybe mushroomes are consumed as food:papua new guinea and other under developed countries,increasing the sevirity of edible species in the inocybe genus. | https://www.wikidoc.org/index.php/Inocybe | |
2413f3869c25d8be56af9bb6f6dcb4ee34707bbb | wikidoc | Inosine | Inosine
Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond.
Inosine is commonly found in tRNAs and is essential for proper translation of the genetic code in wobble base pairs.
Knowledge of inosine metabolism has led to advances in immunotherapy in recent decades. Inosine monophosphate is oxidised by the enzyme inosine monophosphate dehydrogenase, yielding xanthosine monophosphate, a key precursor in purine metabolism. Mycophenolate mofetil is an anti-metabolite, anti-proliferative drug that acts as an inhibitor of inosine monophosphate dehydrogenase. It is used in the treatment of a variety of autoimmune diseases including granulomatosis with polyangiitis because the uptake of purine by actively dividing B cells can exceed 8 times that of normal body cells, and, therefore, this set of white cells (which cannot operate purine salvage pathways) is selectively targeted by the purine deficiency resulting from Inherited Metabolic Diseases (IMD) inhibition.
# Reactions
Adenine is converted to adenosine or inosine monophosphate (IMP), either of which, in turn, is converted into inosine (I), which pairs with Adenine (A), cytosine (C), and uracil (U).
Purine nucleoside phosphorylase intraconverts inosine and hypoxanthine.
Inosine is also an intermediate in a chain of purine nucleotides reactions required for muscle movements.
# Clinical significance
It was tried in the 1970s in Eastern countries for improving athletic performance. Nevertheless, the clinical trials for this purpose showed no improvement.
It has been shown that inosine has neuroprotective properties. It has been proposed for spinal cord injury; because it improves axonal rewiring, and for administration after stroke, because observation has shown that axonal re-wiring is encouraged.
After ingestion, inosine produces uric acid that is suggested to be a natural antioxidant and a peroxynitrite scavenger with potential benefits to patients with multiple sclerosis (MS.) Peroxynitrite has been correlated with axon degeneration . In 2003, a study was initiated at the University of Pennsylvania MS Center to determine whether raising the levels of uric acid by the administration of inosine would slow the progression of MS. The study was completed in 2006 but the results were not reported to NIH. A subsequent publication hinted at potential benefits but the sample size (16 patients) was too small for a definitive conclusion. In addition, the side effect of the treatment was the development of kidney stones in 4 out of 16 patients. Thus, additional studies are necessary to prove the treatment's efficacy.
It is also in phase II trials for Parkinson's disease. Earlier trials had suggested those with the highest serum urate levels had lower progression of Parkinson's symptoms. The trial uses inosine to raise urate levels in those with levels lower than the population mean (6 mg/dL).
Alseres Pharmaceuticals (named Boston Life Sciences when patent was granted) patented the treatment for stroke and is currently investigating the drug in the MS setting.
In the Anatomical Therapeutic Chemical Classification System, it is classified as an antiviral.
# Biotechnology
When designing primers for polymerase chain reaction, inosine is useful in that it can pair with adenine, thymine, or cytosine. This allows for design of primers that span a single-nucleotide polymorphism, without the polymorphism disrupting the primer's annealing efficiency.
However, inosine pairs preferentially with cytidine (C) and its introduction to RNA, e.g. by the action of ADARs, thereby destabilizes double stranded RNA by changing AU base-pairs to
IU mismatches (Bass and Weintraub, Cell, 1988).
# Fitness
Despite lack of clinical evidence that it improves muscle development, inosine remains an ingredient in some fitness supplements.
# Feeding Stimulant
Inosine has also been found to be an important feed stimulant by itself or in combination with certain amino acids in some species of farmed fish. For example, inosine and inosine-5-monophosphate have been reported as specific feeding stimulants for turbot fry, (Scophthalmus maximus) and Japanese amberjack, (Seriola quinqueradiata). The main problem of using inosine and/or inosine-5-monophosphate as feeding attractants is their high cost. However, their use may be economically justified within larval feeds for marine fish larvae during the early weaning period, since the total quantity of feed consumed is relatively low. | Inosine
Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring (also known as a ribofuranose) via a β-N9-glycosidic bond.
Inosine is commonly found in tRNAs and is essential for proper translation of the genetic code in wobble base pairs.
Knowledge of inosine metabolism has led to advances in immunotherapy in recent decades. Inosine monophosphate is oxidised by the enzyme inosine monophosphate dehydrogenase, yielding xanthosine monophosphate, a key precursor in purine metabolism. Mycophenolate mofetil is an anti-metabolite, anti-proliferative drug that acts as an inhibitor of inosine monophosphate dehydrogenase. It is used in the treatment of a variety of autoimmune diseases including granulomatosis with polyangiitis because the uptake of purine by actively dividing B cells can exceed 8 times that of normal body cells, and, therefore, this set of white cells (which cannot operate purine salvage pathways) is selectively targeted by the purine deficiency resulting from Inherited Metabolic Diseases (IMD) inhibition.
# Reactions
Adenine is converted to adenosine or inosine monophosphate (IMP), either of which, in turn, is converted into inosine (I), which pairs with Adenine (A), cytosine (C), and uracil (U).
Purine nucleoside phosphorylase intraconverts inosine and hypoxanthine.
Inosine is also an intermediate in a chain of purine nucleotides reactions required for muscle movements.
# Clinical significance
It was tried in the 1970s in Eastern countries for improving athletic performance. Nevertheless, the clinical trials for this purpose showed no improvement.[1]
It has been shown that inosine has neuroprotective properties. It has been proposed for spinal cord injury;[2] because it improves axonal rewiring, and for administration after stroke, because observation has shown that axonal re-wiring is encouraged.[3]
After ingestion, inosine produces uric acid that is suggested to be a natural antioxidant and a peroxynitrite scavenger with potential benefits to patients with multiple sclerosis (MS.)[4] Peroxynitrite has been correlated with axon degeneration [1]. In 2003, a study was initiated at the University of Pennsylvania MS Center to determine whether raising the levels of uric acid by the administration of inosine would slow the progression of MS.[5] The study was completed in 2006 but the results were not reported to NIH. A subsequent publication hinted at potential benefits but the sample size (16 patients) was too small for a definitive conclusion.[6] In addition, the side effect of the treatment was the development of kidney stones in 4 out of 16 patients. Thus, additional studies are necessary to prove the treatment's efficacy.
It is also in phase II trials for Parkinson's disease. Earlier trials had suggested those with the highest serum urate levels had lower progression of Parkinson's symptoms. The trial uses inosine to raise urate levels in those with levels lower than the population mean (6 mg/dL).[7][8]
Alseres Pharmaceuticals (named Boston Life Sciences when patent was granted) patented the treatment for stroke [2] and is currently investigating the drug in the MS setting.[9]
In the Anatomical Therapeutic Chemical Classification System, it is classified as an antiviral.[10]
# Biotechnology
When designing primers for polymerase chain reaction, inosine is useful in that it can pair with adenine, thymine, or cytosine. This allows for design of primers that span a single-nucleotide polymorphism, without the polymorphism disrupting the primer's annealing efficiency.
However, inosine pairs preferentially with cytidine (C) and its introduction to RNA, e.g. by the action of ADARs, thereby destabilizes double stranded RNA by changing AU base-pairs to
IU mismatches (Bass and Weintraub, Cell, 1988).
# Fitness
Despite lack of clinical evidence that it improves muscle development, inosine remains an ingredient in some fitness supplements.
# Feeding Stimulant
Inosine has also been found to be an important feed stimulant by itself or in combination with certain amino acids in some species of farmed fish. For example, inosine and inosine-5-monophosphate have been reported as specific feeding stimulants for turbot fry, (Scophthalmus maximus) [11] and Japanese amberjack, (Seriola quinqueradiata).[12] The main problem of using inosine and/or inosine-5-monophosphate as feeding attractants is their high cost. However, their use may be economically justified within larval feeds for marine fish larvae during the early weaning period, since the total quantity of feed consumed is relatively low. | https://www.wikidoc.org/index.php/Inosine | |
87ca2862cc5d00d18dd84a5992104a448cb7a67a | wikidoc | Patient | Patient
A patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and in need of treatment by a physician or other medical professional. Health consumer, health care consumer or client are other names for patient, usually used by governmental agencies, insurance companies, and/or patient groups (who may object to some implications of the word 'patient').
# Etymology
The word patient is derived from the Latin word patiens, the present participle of the deponent verb pati, meaning "one who endures" or "one who suffers".
Patient is also the adjective form of patience. Both senses of the word share a common origin.
In itself the definition of patient doesn't imply suffering or passivity but the role it describes is often associated with the definitions of the adjective form: enduring trying circumstances with even temper. Some have argued recently that the term should be dropped, because it underlines the inferior status of recipients of health care.
For them, "the active patient is a contradiction in terms, and it is the assumption underlying the passivity that is the most dangerous". Unfortunately none of the alternative terms seem to offer a better definition.
- Client, whose Latin root cliens means "one who is obliged to make supplications to a powerful figure for material assistance", carries a sense of subservience.
- Consumer suggest both a financial relationship and a particular social/political stance, implying that health care services operate exactly like all other commercial markets. Many reject that term on the grounds that consumerism is an individualistic concept that fails to capture the particularity of health care systems.
# Outpatient vs inpatient
An outpatient is a patient who only comes to a hospital or doctor for diagnosis and/or therapy and then leaves again.
An inpatient on the other hand is 'admitted' to the hospital and stays overnight or for an indeterminate time, usually several days or weeks (though some cases, like coma patients, have stayed in hospitals for decades). | Patient
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
A patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and in need of treatment by a physician or other medical professional. Health consumer, health care consumer or client are other names for patient, usually used by governmental agencies, insurance companies, and/or patient groups (who may object to some implications of the word 'patient').
# Etymology
The word patient is derived from the Latin word patiens, the present participle of the deponent verb pati, meaning "one who endures" or "one who suffers".
Patient is also the adjective form of patience. Both senses of the word share a common origin.
In itself the definition of patient doesn't imply suffering or passivity but the role it describes is often associated with the definitions of the adjective form: enduring trying circumstances with even temper. Some have argued recently that the term should be dropped, because it underlines the inferior status of recipients of health care.
[1]
.
For them, "the active patient is a contradiction in terms, and it is the assumption underlying the passivity that is the most dangerous". Unfortunately none of the alternative terms seem to offer a better definition.
- Client, whose Latin root cliens means "one who is obliged to make supplications to a powerful figure for material assistance", carries a sense of subservience.
- Consumer suggest both a financial relationship and a particular social/political stance, implying that health care services operate exactly like all other commercial markets. Many reject that term on the grounds that consumerism is an individualistic concept that fails to capture the particularity of health care systems.
# Outpatient vs inpatient
An outpatient is a patient who only comes to a hospital or doctor for diagnosis and/or therapy and then leaves again.
An inpatient on the other hand is 'admitted' to the hospital and stays overnight or for an indeterminate time, usually several days or weeks (though some cases, like coma patients, have stayed in hospitals for decades). | https://www.wikidoc.org/index.php/Inpatient | |
f28d504ba0b48fc4bff714b0821b92e0dd50fe30 | wikidoc | Integer | Integer
The integers (from the Latin integer, which means with untouched integrity, whole, entire) are the set of numbers consisting of the natural numbers including 0 (0, 1, 2, 3, ...) and their negatives (0, −1, −2, −3, ...). They are numbers that can be written without a fractional or decimal component, and fall within the set {... −2, −1, 0, 1, 2, ...}. For example, 65, 7, and −756 are integers; 1.6 and 1½ are not integers. In other terms, integers are the numbers one can count with items such as apples or fingers, and their negatives, including 0.
More formally, the integers are the only integral domain whose positive elements are well-ordered, and in which order is preserved by addition. Like the natural numbers, the integers form a countably infinite set. The set of all integers is often denoted by a boldface Z (or blackboard bold \mathbb{Z}, Unicode U+2124 ℤ), which stands for Zahlen (German for numbers).
In algebraic number theory, these commonly understood integers, embedded in the field of rational numbers, are referred to as rational integers to distinguish them from the more broadly defined algebraic integers.
# Algebraic properties
Like the natural numbers, Z is closed under the operations of addition and multiplication, that is, the sum and product of any two integers is an integer. However, with the inclusion of the negative natural numbers, and, importantly, zero, Z (unlike the natural numbers) is also closed under subtraction. Z is not closed under the operation of division, since the quotient of two integers (e.g., 1 divided by 2), need not be an integer.
The following lists some of the basic properties of addition and multiplication for any integers a, b and c.
In the language of abstract algebra, the first five properties listed above for addition say that Z under addition is an abelian group. As a group under addition, Z is a cyclic group, since every nonzero integer can be written as a finite sum 1 + 1 + ... 1 or (−1) + (−1) + ... + (−1). In fact, Z under addition is the only infinite cyclic group, in the sense that any infinite cyclic group is isomorphic to Z.
The first four properties listed above for multiplication say that Z under multiplication is a commutative monoid. However, note that not every integer has a multiplicative inverse; e.g. there is no integer x such that 2x = 1, because the left hand side is even, while the right hand side is odd. This means that Z under multiplication is not a group.
All the rules from the above property table, except for the last, taken together say that Z together with addition and multiplication is a commutative ring with unity. Adding the last property says that Z is an integral domain. In fact, Z provides the motivation for defining such a structure.
The lack of multiplicative inverses, which is equivalent to the fact that Z is not closed under division, means that Z is not a field. The smallest field containing the integers is the field of rational numbers. This process can be mimicked to form the field of fractions of any integral domain.
Although ordinary division is not defined on Z, it does possess an important property called the division algorithm: that is, given two integers a and b with b ≠ 0, there exist unique integers q and r such that a = q × b + r and 0 ≤ r < |b|, where |b| denotes the absolute value of b. The integer q is called the quotient and r is called the remainder, resulting from division of a by b. This is the basis for the Euclidean algorithm for computing greatest common divisors.
Again, in the language of abstract algebra, the above says that Z is a Euclidean domain. This implies that Z is a principal ideal domain and any positive integer can be written as the products of primes in an essentially unique way. This is the fundamental theorem of arithmetic.
# Order-theoretic properties
Z is a totally ordered set without upper or lower bound. The ordering of Z is given by
An integer is positive if it is greater than zero and negative if it is less than zero. Zero is defined as neither negative nor positive.
The ordering of integers is compatible with the algebraic operations in the following way:
- if a < b and c < d, then a + c < b + d
- if a bc.)
It follows that Z together with the above ordering is an ordered ring.
# Construction
The integers can be constructed from the natural numbers by defining equivalence classes of pairs of natural numbers N×N under an equivalence relation, "~", where
precisely when
Taking 0 to be a natural number, the natural numbers may be considered to be integers by the embedding that maps n to , where denotes the equivalence class having (a,b) as a member.
Addition and multiplication of integers are defined as follows:
It is easily verified that the result is independent of the choice of representatives of the equivalence classes.
Typically, is denoted by
where
If the natural numbers are identified with the corresponding integers (using the embedding mentioned above), this convention creates no ambiguity.
This notation recovers the familiar representation of the integers as {...,−3,−2,−1,0,1,2,3,...}.
Some examples are:
-1 &= &= &= \cdots & &= \\
-2 &= &= &= \cdots & &=
\end{align}
# Integers in computing
An integer (sometimes known as an "int", from the name of a datatype in the C programming language) is often a primitive datatype in computer languages. However, integer datatypes can only represent a subset of all integers, since practical computers are of finite capacity. Also, in the common two's complement representation, the inherent definition of sign distinguishes between "negative" and "non-negative" rather than "negative, positive, and 0". (It is, however, certainly possible for a computer to determine whether an integer value is truly positive.)
Variable-length representations of integers, such as bignums, can store any integer that fits in the computer's memory. Other integer datatypes are implemented with a fixed size, usually a number of bits which is a power of 2 (4, 8, 16, etc.) or a memorable number of decimal digits (e.g., 9 or 10).
In contrast, theoretical models of digital computers, such as Turing machines, typically do not have infinite (but only unbounded finite) capacity.
# Cardinality
The cardinality of the set of integers is equal to \aleph_0. This is readily demonstrated by the construction of a bijection, that is, a function that is injective and surjective from \mathbb{Z} to \mathbb{N}. Consider the function
If the domain is restricted to \mathbb{Z} then each and every member of \mathbb{Z} has one and only one corresponding member of \mathbb{N} and by the definition of cardinal equality the two sets have equal cardinality.
# Notes
- ↑ "Earliest Uses of Symbols of Number Theory" | Integer
The integers (from the Latin integer, which means with untouched integrity, whole, entire) are the set of numbers consisting of the natural numbers including 0 (0, 1, 2, 3, ...) and their negatives (0, −1, −2, −3, ...). They are numbers that can be written without a fractional or decimal component, and fall within the set {... −2, −1, 0, 1, 2, ...}. For example, 65, 7, and −756 are integers; 1.6 and 1½ are not integers. In other terms, integers are the numbers one can count with items such as apples or fingers, and their negatives, including 0.
More formally, the integers are the only integral domain whose positive elements are well-ordered, and in which order is preserved by addition. Like the natural numbers, the integers form a countably infinite set. The set of all integers is often denoted by a boldface Z (or blackboard bold <math>\mathbb{Z}</math>, Unicode U+2124 ℤ), which stands for Zahlen (German for numbers).[1]
In algebraic number theory, these commonly understood integers, embedded in the field of rational numbers, are referred to as rational integers to distinguish them from the more broadly defined algebraic integers.
# Algebraic properties
Like the natural numbers, Z is closed under the operations of addition and multiplication, that is, the sum and product of any two integers is an integer. However, with the inclusion of the negative natural numbers, and, importantly, zero, Z (unlike the natural numbers) is also closed under subtraction. Z is not closed under the operation of division, since the quotient of two integers (e.g., 1 divided by 2), need not be an integer.
The following lists some of the basic properties of addition and multiplication for any integers a, b and c.
In the language of abstract algebra, the first five properties listed above for addition say that Z under addition is an abelian group. As a group under addition, Z is a cyclic group, since every nonzero integer can be written as a finite sum 1 + 1 + ... 1 or (−1) + (−1) + ... + (−1). In fact, Z under addition is the only infinite cyclic group, in the sense that any infinite cyclic group is isomorphic to Z.
The first four properties listed above for multiplication say that Z under multiplication is a commutative monoid. However, note that not every integer has a multiplicative inverse; e.g. there is no integer x such that 2x = 1, because the left hand side is even, while the right hand side is odd. This means that Z under multiplication is not a group.
All the rules from the above property table, except for the last, taken together say that Z together with addition and multiplication is a commutative ring with unity. Adding the last property says that Z is an integral domain. In fact, Z provides the motivation for defining such a structure.
The lack of multiplicative inverses, which is equivalent to the fact that Z is not closed under division, means that Z is not a field. The smallest field containing the integers is the field of rational numbers. This process can be mimicked to form the field of fractions of any integral domain.
Although ordinary division is not defined on Z, it does possess an important property called the division algorithm: that is, given two integers a and b with b ≠ 0, there exist unique integers q and r such that a = q × b + r and 0 ≤ r < |b|, where |b| denotes the absolute value of b. The integer q is called the quotient and r is called the remainder, resulting from division of a by b. This is the basis for the Euclidean algorithm for computing greatest common divisors.
Again, in the language of abstract algebra, the above says that Z is a Euclidean domain. This implies that Z is a principal ideal domain and any positive integer can be written as the products of primes in an essentially unique way. This is the fundamental theorem of arithmetic.
# Order-theoretic properties
Z is a totally ordered set without upper or lower bound. The ordering of Z is given by
An integer is positive if it is greater than zero and negative if it is less than zero. Zero is defined as neither negative nor positive.
The ordering of integers is compatible with the algebraic operations in the following way:
- if a < b and c < d, then a + c < b + d
- if a < b and 0 < c, then ac < bc. (From this fact, one can show that if c < 0, then ac > bc.)
It follows that Z together with the above ordering is an ordered ring.
# Construction
The integers can be constructed from the natural numbers by defining equivalence classes of pairs of natural numbers N×N under an equivalence relation, "~", where
precisely when
Taking 0 to be a natural number, the natural numbers may be considered to be integers by the embedding that maps n to [(n,0)], where [(a,b)] denotes the equivalence class having (a,b) as a member.
Addition and multiplication of integers are defined as follows:
It is easily verified that the result is independent of the choice of representatives of the equivalence classes.
Typically, [(a,b)] is denoted by
where
If the natural numbers are identified with the corresponding integers (using the embedding mentioned above), this convention creates no ambiguity.
This notation recovers the familiar representation of the integers as {...,−3,−2,−1,0,1,2,3,...}.
Some examples are:
-1 &= [(0,1)] &= [(1,2)] &= \cdots & &= [(k,k+1)] \\
-2 &= [(0,2)] &= [(1,3)] &= \cdots & &= [(k,k+2)]
\end{align}</math>
# Integers in computing
An integer (sometimes known as an "int", from the name of a datatype in the C programming language) is often a primitive datatype in computer languages. However, integer datatypes can only represent a subset of all integers, since practical computers are of finite capacity. Also, in the common two's complement representation, the inherent definition of sign distinguishes between "negative" and "non-negative" rather than "negative, positive, and 0". (It is, however, certainly possible for a computer to determine whether an integer value is truly positive.)
Variable-length representations of integers, such as bignums, can store any integer that fits in the computer's memory. Other integer datatypes are implemented with a fixed size, usually a number of bits which is a power of 2 (4, 8, 16, etc.) or a memorable number of decimal digits (e.g., 9 or 10).
In contrast, theoretical models of digital computers, such as Turing machines, typically do not have infinite (but only unbounded finite) capacity.
# Cardinality
The cardinality of the set of integers is equal to <math>\aleph_0</math>. This is readily demonstrated by the construction of a bijection, that is, a function that is injective and surjective from <math>\mathbb{Z}</math> to <math>\mathbb{N}</math>. Consider the function
If the domain is restricted to <math>\mathbb{Z}</math> then each and every member of <math>\mathbb{Z}</math> has one and only one corresponding member of <math>\mathbb{N}</math> and by the definition of cardinal equality the two sets have equal cardinality.
# Notes
- ↑ "Earliest Uses of Symbols of Number Theory" | https://www.wikidoc.org/index.php/Integer | |
ccd1c67c0f13283d45819af044953fc043a28c16 | wikidoc | Ocellus | Ocellus
# Overview
An ocellus (plural: ocelli) is a type of photoreceptor organ in animals. Also called "simple eyes", ocelli are miniature eyes capable of sensing light but not distinguishing its direction. See also stemmata, which are structurally similar. Ocelli are found in many invertebrates. Insects in particular have two types of ocelli, dorsal ocelli and lateral ocelli.
# Photoreceptors
In insects, ocelli are involved (along with compound eyes) in the horizon-detecting response, decreasing the latency between horizon changes and the insect's response.
## Dorsal Ocelli
Dorsal ocelli are light-sensitive organs on the dorsal surface or on the top of the head. There are generally three, forming a triangle.
They consist of a few dozen rod cells covered with a corneal lens. In some species, such as locusts, dorsal ocelli may contain several hundreds of retinula cells. Insects with dorsal ocelli also have compound eyes.
## Lateral Ocelli
Lateral ocelli have a mixture of rod cells and cone cells and are found on the sides of the head, one to six on each side.
Lateral ocelli are the only eyes of the larvae of several orders of insects (fleas, springtails, silverfish, and Strepsiptera). | Ocellus
# Overview
An ocellus (plural: ocelli) is a type of photoreceptor organ in animals. Also called "simple eyes", ocelli are miniature eyes capable of sensing light but not distinguishing its direction. See also stemmata, which are structurally similar. Ocelli are found in many invertebrates. Insects in particular have two types of ocelli, dorsal ocelli and lateral ocelli.
# Photoreceptors
In insects, ocelli are involved (along with compound eyes) in the horizon-detecting response, decreasing the latency between horizon changes and the insect's response.
## Dorsal Ocelli
Dorsal ocelli are light-sensitive organs on the dorsal surface or on the top of the head. There are generally three, forming a triangle.
They consist of a few dozen rod cells covered with a corneal lens. In some species, such as locusts, dorsal ocelli may contain several hundreds of retinula cells. Insects with dorsal ocelli also have compound eyes.
## Lateral Ocelli
Lateral ocelli have a mixture of rod cells and cone cells and are found on the sides of the head, one to six on each side.
Lateral ocelli are the only eyes of the larvae of several orders of insects (fleas, springtails, silverfish, and Strepsiptera).
# External links
- John R. Meyer, Photoreceptors
de:Ocellus
nl:Ocellus
no:Medianøye
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Invertebrate_photoreceptor | |
8a7fcb9a3b8db385e4f21bac6508b7bac77be883 | wikidoc | Iohexol | Iohexol
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
# Overview
Iohexol is a contrast media that is FDA approved for the diagnosis of intrathecal administration in adults including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography (myelography, cisternography, ventriculography. Common adverse reactions include headaches, pain, nausea, vomiting and dizziness.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
- Iohexol is indicated for intrathecal administration in adults including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography (myelography, cisternography, ventriculography).
- The volume and concentration of Iohexol to be administered will depend on the degree and extent of contrast required in the area(s) under examination and on the equipment and technique employed.
- Iohexol at a concentration of 300 mgI/mL is recommended for the examination of the lumbar, thoracic, and cervical regions in adults by lumbar or direct cervical injection and is slightly hypertonic to CSF.
- A total dose of 3060 mg iodine or a concentration of 300 mgI/mL should not be exceeded in adults in a single myelographic examination. This is based on clinical trial evaluation to date. As in all diagnostic procedures, the minimum volume and dose to produce adequate visualization should be used. Most procedures do not require either maximum dose or concentration.
- Anesthesia is not necessary. Premedication sedatives or tranquilizers are usually not needed. Patients should be well hydrated prior to and following contrast administration.
- Seizure-prone patients should be maintained on anticonvulsant medication.
- Many radiopaque contrast agents are incompatible in vitro with some antihistamines and many other drugs; therefore, concurrent drugs should not be physically admixed with contrast agents.
- To avoid excessive mixing with CSF and consequent dilution of contrast, injection should be made slowly over 1 to 2 minutes.
- Depending on the estimated volume of contrast medium which may be required for the procedure a small amount of CSF may be removed to minimize distention of the subarachnoid spaces.
- The lumbar or cervical puncture needle may be removed immediately following injection since it is not necessary to remove OMNIPAQUE after injection into the subarachnoid space.
- The usual recommended total doses for use in lumbar, thoracic, cervical, and total columnar myelography in adults are 1.2 gI to 3.0 gI as follows:
- Refer to DIRECTIONS FOR PROPER USE OF OMNIPAQUE PHARMACY BULK PACKAGE section for instructions.
- Parenteral products should be inspected visually for particulate matter or discoloration prior to administration. If particulate matter or discoloration is present, do not use.
- If in the clinical judgment of the physician sequential or repeat examinations are required, a suitable interval of time between administrations should be observed to allow for normal clearance of the drug from the body. An interval of at least 48 hours should be allowed before repeat examination; however, whenever possible, 5 to 7 days is recommended.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Iohexol in adult patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Iohexol in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Iohexol in pediatric patients.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Iohexol in pediatric patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Iohexol in pediatric patients.
# Contraindications
- OMNIPAQUE should not be administered to patients with a known hypersensitivity to iohexol.
# Warnings
- Nonionic iodinated contrast media inhibit blood coagulation, in vitro, less than ionic contrast media. Clotting has been reported when blood remains in contact with syringes containing nonionic contrast media.
- Serious, rarely fatal, thromboembolic events causing myocardial infarction and stroke have been reported during angiographic procedures with both ionic and nonionic contrast media. Therefore, meticulous intravascular administration technique is necessary, particularly during angiographic procedures, to minimize thromboembolic events. Numerous factors, including length of procedure, catheter and syringe material, underlying disease state, and concomitant medications may contribute to the development of thromboembolic events. For these reasons, meticulous angiographic techniques are recommended including close attention to guidewire and catheter manipulation, use of manifold systems and/or three-way stopcocks, frequent catheter flushing with heparinized saline solutions and minimizing the length of the procedure. The use of plastic syringes in place of glass syringes has been reported to decrease but not eliminate the likelihood of in vitro clotting.
- OMNIPAQUE should be used with extreme care in patients with severe functional disturbances of the liver and kidneys, severe thyrotoxicosis, or myelomatosis. Diabetics with a serum creatinine level above 3 mg/dL should not be examined unless the possible benefits of the examination clearly outweigh the additional risk. OMNIPAQUE is not recommended for use in patients with anuria.
- Radiopaque contrast agents are potentially hazardous in patients with multiple myeloma or other paraproteinemia, particularly in those with therapeutically resistant anuria. Although neither the contrast agent nor dehydration has separately proven to be the cause of anuria in myeloma, it has been speculated that the combination of both may be causative factors. The risk in myelomatous patients is not a contraindication; however, special precautions are necessary. Partial dehydration in the preparation of these patients prior to injection is not recommended since this may predispose the patient to precipitation of the myeloma protein in the renal tubules. No form of therapy, including dialysis, has been successful in reversing the effect. Myeloma, which occurs most commonly in persons over age 40, should be considered before instituting intravascular administration of contrast agents.
- Ionic contrast media, when injected intravenously or intra-arterially, may promote sickling in individuals who are homozygous for sickle cell disease.
- Administration of radiopaque materials to patients known or suspected of having pheochromocytoma should be performed with extreme caution. If, in the opinion of the physician, the possible benefits of such procedures outweigh the considered risks, the procedures may be performed; however, the amount of radiopaque medium injected should be kept to an absolute minimum. The patient's blood pressure should be assessed throughout the procedure and measures for the treatment of hypertensive crisis should be readily available. Reports of thyroid storm following the use of iodinated, ionic radiopaque contrast media in patients with hyperthyroidism or with an autonomously functioning thyroid nodule suggest that this additional risk be evaluated in such patients before use of any contrast medium.
- Urography should be performed with caution in patients with severely impaired renal function and patients with combined renal and hepatic disease.
# Adverse Reactions
## Clinical Trials Experience
There is limited information regarding Clinical Trial Experience of Iohexol in the drug label.
## Postmarketing Experience
- Adverse reactions following the use of Iohexol and OMNIPAQUE 350 are usually of mild to moderate severity. However, serious, life-threatening and fatal reactions, mostly of cardiovascular origin, have been associated with the administration of iodine-containing contrast media, including OMNIPAQUE.
- The injection of contrast media is frequently associated with the sensation of warmth and pain, especially in peripheral angiography; pain and warmth are less frequent and less severe with OMNIPAQUE than with many contrast media.
- Cardiovascular System
- Arrhythmias including PVCs and PACs (2%), angina/chest pain (1%), and hypotension (0.7%). Others including cardiac failure, asystole, bradycardia, tachycardia, and vasovagal reaction were reported with an individual incidence of 0.3% or less. In controlled clinical trials involving 1485 patients, one fatality occurred. A cause and effect relationship between this death and iohexol has not been established.
- Nervous System
- Vertigo (including dizziness and lightheadedness) (0.5%), pain (3%), vision abnormalities (including blurred vision and photomas) (2%), headache (2%), and taste perversion (1%). Others including anxiety, fever, motor and speech dysfunction, convulsion, paresthesia, somnolence, stiff neck, hemiparesis, syncope, shivering, transient ischemic attack, cerebral infarction, and nystagmus were reported, with an individual incidence of 0.3% or less.
- Respiratory System
- Dyspnea, rhinitis, coughing, and laryngitis, with an individual incidence of 0.2% or less.
- Gastrointestinal System
- Nausea (2%) and vomiting (0.7%). Others including diarrhea, dyspepsia, cramp, and dry mouth were reported, with an individual incidence of less than 0.1%.
- Skin and Appendages
- Urticaria (0.3%), purpura (0.1%), abscess (0.1%), and pruritus (0.1%).
- Individual adverse reactions which occurred to a significantly greater extent for a specific procedure are listed under that indication.
- In controlled clinical trials involving 391 patients for pediatric angiocardiography, urography, and contrast enhanced computed tomographic head imaging, adverse reactions following the use of Iohexol and OMNIPAQUE 350 were generally less frequent than with adults.
- Cardiovascular System
- Ventricular tachycardia (0.5%), 2:1 heart block (0.5%), hypertension (0.3%), and anemia (0.3%).
- Nervous System
- Pain (0.8%), fever (0.5%), taste abnormality (0.5%), and convulsion (0.3%).
- Respiratory System
- Congestion (0.3%) and apnea (0.3%).
- Gastrointestinal System
- Nausea (1%), hypoglycemia (0.3%), and vomiting (2%).
- Skin and Appendages
- Rash (0.3%).
- Physicians should remain alert for the occurrence of adverse effects in addition to those discussed above.
- The following reactions have been reported after administration of other intravascular iodinated contrast media, and rarely with iohexol. Reactions due to technique: hematomas and ecchymoses. Hemodynamic reactions: vein cramp and thrombophlebitis following intravenous injection. Cardiovascular reactions: rare cases of cardiac arrhythmias, reflex tachycardia, chest pain, cyanosis, hypertension, hypotension, peripheral vasodilatation, shock, and cardiac arrest. Renal reactions: occasionally, transient proteinuria and rarely, oliguria or anuria. Allergic reactions: asthmatic attacks, nasal and conjunctival symptoms, dermal reactions such as urticaria with or without pruritus, as well as pleomorphic rashes, sneezing and lacrimation and, rarely, naphylactic reactions. Rare fatalities have occurred, due to this or unknown causes. Signs and symptoms related to the respiratory system: pulmonary or laryngeal edema, bronchospasm, dyspnea; or to the nervous system: restlessness, tremors, convulsions. Other reactions: flushing, pain, warmth, metallic taste, nausea, vomiting, anxiety, headache, confusion, pallor, weakness, sweating, localized areas of edema, especially facial cramps, neutropenia, and dizziness. Rarely, immediate or delayed rigors can occur, sometimes accompanied by yperpyrexia.
- Infrequently, "iodism" (salivary gland swelling) from organic iodinated compounds appears two days after exposure and subsides by the sixth day.
- In general, the reactions which are known to occur upon parenteral administration of iodinated contrast agents are possible with any nonionic agent. Approximately 95 percent of adverse reactions accompanying the use of water-soluble intravascularly administered contrast agents are mild to moderate in degree. However, severe, life-threatening anaphylactoid reactions, mostly of cardiovascular origin, have occurred. Reported incidences of death range from 6.6 per 1 million (0.00066 percent) to 1 in 10,000 (0.01 percent). Most deaths occur during injection or 5 to 10 minutes later; the main feature being cardiac arrest with cardiovascular disease as the main aggravating factor. Isolated reports of hypotensive collapse and shock are found in the literature. The incidence of shock is estimated to be 1 out of 20,000 (0.005 percent) patients.
- Adverse reactions to injectable contrast media fall into two categories: chemotoxic reactions and idiosyncratic reactions.
- Chemotoxic reactions result from the physicochemical properties of the contrast media, the dose, and speed of injection. All hemodynamic disturbances and injuries to organs or vessels perfused by the contrast medium are included in this category.
- Idiosyncratic reactions include all other reactions. They occur more frequently in patients 20 to 40 years old. Idiosyncratic reactions may or may not be dependent on the amount of dose injected, the speed of injection, and the radiographic procedure. Idiosyncratic reactions are subdivided into minor, intermediate, and severe. The minor reactions are self-limited and of short duration; the severe reactions are life-threatening and treatment is urgent and mandatory.
- The reported incidence of adverse reactions to contrast media in patients with a history of allergy are twice that of the general population. Patients with a history of previous reactions to a contrast medium are three times more susceptible than other patients. However, sensitivity to contrast media does not appear to increase with repeated examinations.
- Most adverse reactions to injectable contrast media appear within 1 to 3 minutes after the start of injection, but delayed reactions may occur.
- Regardless of the contrast agent employed, the overall estimated incidence of serious adverse reactions is higher with angiocardiography than with other procedures. Cardiac decompensation, serious arrhythmias, angina pectoris, or myocardial ischemia or infarction may occur during angiocardiography and left ventriculography. Electrocardiographic and hemodynamic abnormalities occur less frequently with OMNIPAQUE than with diatrizoate meglumine and diatrizoate sodium injection.
- In controlled clinical trials involving 285 adult patients for various body cavity examinations using Iohexol and 350, the following adverse reactions were reported.
- Incidence > 1%: None
- Incidence ≤ 1%: Hypertension
- Incidence > 1%: Pain (26%)
- Incidence ≤ 1%: Headache, somnolence, fever, muscle weakness, burning, unwell feeling, tremors, lightheadedness, syncope
- None
- Incidence > 1%: None
- Incidence ≤ 1%: Flatulence, diarrhea, nausea, vomiting, abdominal pressure
- Incidence > 1%: Swelling (22%), heat (7%)
- Incidence ≤ 1%: Hematoma at injection site
- The most frequent reactions, pain and swelling, were almost exclusively reported after arthrography and were generally related to the procedure rather than the contrast medium. Gastrointestinal reactions were almost exclusively reported after oral pass-thru examinations.
- No adverse reactions associated with the use of OMNIPAQUE for VCU procedures were reported in 51 pediatric patients studied.
# Drug Interactions
There is limited information regarding Iohexol Drug Interactions in the drug label.
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA): B
- Reproduction studies performed in rats and rabbits at dosages up to 4.0 gI/kg and 2.5 gI/kg, respectively have not revealed evidence of impaired fertility or harm to the fetus due to OMNIPAQUE. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Iohexol in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Iohexol during labor and delivery.
### Nursing Mothers
- It is not known to what extent iohexol is excreted in human milk. However, many injectable contrast agents are excreted unchanged in human milk. Although it has not been established that serious adverse reactions occur in nursing infants, caution should be exercised when intravascular contrast media are administered to nursing women. Bottle feedings may be substituted for breast feedings for 24 hours following administration of OMNIPAQUE.
### Pediatric Use
- Pediatric patients at higher risk of experiencing adverse events during contrast medium administration may include those having asthma, a sensitivity to medication and/or allergens, congestive heart failure, a serum creatinine greater than 1.5 mg/dL or those less than 12 months of age.
### Geriatic Use
There is no FDA guidance on the use of Iohexol with respect to geriatric patients.
### Gender
There is no FDA guidance on the use of Iohexol with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Iohexol with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Iohexol in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Iohexol in patients with hepatic impairment.
### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Iohexol in women of reproductive potentials and males.
### Immunocompromised Patients
There is no FDA guidance one the use of Iohexol in patients who are immunocompromised.
# Administration and Monitoring
### Administration
- Intrathecal
- Intravascular
- Oral
### Monitoring
- During administration of large doses of OMNIPAQUE 350, continuous monitoring of vital signs is desirable.
# IV Compatibility
There is limited information regarding IV Compatibility of Iohexol in the drug label.
# Overdosage
- Overdosage may occur. The adverse effects of overdosage are life-threatening and affect mainly the pulmonary and cardiovascular systems. The symptoms included: cyanosis, bradycardia, acidosis, pulmonary hemorrhage, convulsions, coma, and cardiac arrest. Treatment of an overdosage is directed toward the support of all vital functions, and prompt institution of symptomatic therapy.
- The intravenous LD50 values of OMNIPAQUE (in grams of iodine per kilogram body weight) are 24.2 in mice and 15.0 in rats.
# Pharmacology
## Mechanism of Action
- Following intravascular injection, iohexol is distributed in the extracellular fluid compartment and is excreted unchanged by glomerular filtration. It will opacify those vessels in the path of flow of the contrast medium permitting radiographic visualization of the internal structures until significant hemodilution occurs.
- Approximately 90% or more of the injected dose is excreted within the first 24 hours, with the peak urine concentrations occurring in the first hour after administration. Plasma and urine iohexol levels indicate that the iohexol body clearance is due primarily to renal clearance. An increase in the dose from 500 mgI/kg to 1500 mgI/kg does not significantly alter the clearance of the drug. The following pharmacokinetic values were observed following the intravenous administration of iohexol (between 500 mgI/kg to 1500 mgI/kg) to 16 adult human subjects: renal clearance—120 (86-162) mL/min; total body clearance—131 (98-165) mL/min; and volume of distribution—165 (108-219) mL/kg.
- Renal accumulation is sufficiently rapid that the period of maximal opacification of the renal passages may begin as early as 1 minute after intravenous injection. Urograms become apparent in about 1 to 3 minutes with optimal contrast occurring between 5 to 15 minutes. In nephropathic conditions, particularly when excretory capacity has been altered, the rate of excretion may vary unpredictably, and opacification may be delayed after injection. Severe renal impairment may result in a lack of diagnostic opacification of the collecting system and, depending on the degree of renal impairment, prolonged plasma iohexol levels may be anticipated. In these patients, as well as in infants with immature kidneys, the route of excretion through the gallbladder and into the small intestine may increase.
- Iohexol displays a low affinity for serum or plasma proteins and is poorly bound to serum albumin. No significant metabolism, deiodination or biotransformation occurs.
- OMNIPAQUE probably crosses the placental barrier in humans by simple diffusion. It is not known to what extent iohexol is excreted in human milk.
- Animal studies indicate that iohexol does not cross an intact blood-brain barrier to any significant extent following intravascular administration.
- OMNIPAQUE enhances computed tomographic imaging through augmentation of radiographic efficiency. The degree of density enhancement is directly related to the iodine content in an administered dose; peak iodine blood levels occur immediately following rapid intravenous injection. Blood levels fall rapidly within 5 to 10 minutes and the vascular compartment half-life is approximately 20 minutes. This can be accounted for by the dilution in the vascular and extravascular fluid compartments which causes an initial sharp fall in plasma concentration. Equilibration with the extracellular compartments is reached in about ten minutes; thereafter, the fall becomes exponential.
- The pharmacokinetics of iohexol in both normal and abnormal tissue have been shown to be variable. Contrast enhancement appears to be greatest immediately after bolus administration (15 seconds to 120 seconds). Thus, greatest enhancement may be detected by a series of consecutive two-to-three second scans performed within 30 to 90 seconds after injection (ie, dynamic computed tomographic imaging). Utilization of a continuous scanning technique (ie, dynamic CT scanning) may improve enhancement and diagnostic assessment of tumor and other lesions such as abscess, occasionally revealing unsuspected or more extensive disease. For example, a cyst may be distinguished from a vascularized solid lesion when precontrast and enhanced scans are compared; the nonperfused mass shows unchanged x-ray absorption (CT number). A vascularized lesion is characterized by an increase in CT number in the few minutes after a bolus of intravascular contrast agent; it may be malignant, benign, or normal tissue, but would probably not be a cyst, hematoma, or other nonvascular lesion.
- Because unenhanced scanning may provide adequate diagnostic information in the individual patient, the decision to employ contrast enhancement, which may be associated with risk and increased radiation exposure, should be based upon a careful evaluation of clinical, other radiological, and unenhanced CT findings.
- In contrast enhanced computed tomographic head imaging, OMNIPAQUE does not accumulate in normal brain tissue due to the presence of the normal blood-brain barrier. The increase in x-ray absorption in normal brain is due to the presence of contrast agent within the blood pool. A break in the blood-brain barrier such as occurs in malignant tumors of the brain allows for the accumulation of contrast medium within the interstitial tissue of the tumor. Adjacent normal brain tissue does not contain the contrast medium.
- Maximum contrast enhancement in tissue frequently occurs after peak blood iodine levels are reached. A delay in maximum contrast enhancement can occur. Diagnostic contrast enhanced images of the brain have been obtained up to 1 hour after intravenous bolus administration. This delay suggests that radiographic contrast enhancement is at least in part dependent on the accumulation of iodine containing medium within the lesion and outside the blood pool, although the mechanism by which this occurs is not clear. The radiographic enhancement of nontumoral lesions, such as arteriovenous malformations and aneurysms, is probably dependent on the iodine content of the circulating blood pool.
- In patients where the blood-brain barrier is known or suspected to be disrupted, the use of any radiographic contrast medium must be assessed on an individual risk to benefit basis. However, compared to ionic media, nonionic media are less toxic to the central nervous system.
- In contrast enhanced computed tomographic body imaging (nonneural tissue), OMNIPAQUE diffuses rapidly from the vascular into the extravascular space. Increase in x-ray absorption is related to blood flow, concentration of the contrast medium, and extraction of the contrast medium by interstitial tissue of tumors since no barrier exists. Contrast enhancement is thus due to the relative differences in extravascular diffusion between normal and abnormal tissue, quite different from that in the brain.
- Examinations of the uterus (hysterosalpingography) and bladder (voiding cystourethrography) involve the almost immediate drainage of contrast medium from the cavity upon conclusion of the radiographic procedure.
- Orally administered iohexol is very poorly absorbed from the normal gastrointestinal tract. Only 0.1 to 0.5 percent of the oral dose was excreted by the kidneys. This amount may increase in the presence of bowel perforation or bowel obstruction. Iohexol is well tolerated and readily absorbed if leakage into the peritoneal cavity occurs.
- Visualization of the joint spaces, uterus, fallopian tubes, peritoneal herniations, pancreatic and bile ducts, and bladder can be accomplished by direct injection of contrast medium into the region to be studied. The use of appropriate iodine concentrations assures diagnostic density.
- Orally administered OMNIPAQUE produces good visualization of the gastrointestinal tract. OMNIPAQUE is particularly useful when barium sulfate is contraindicated as in patients with suspected bowel perforation or those where aspiration of contrast medium is a possibility.
## Structure
- Iohexol, N,N´ - Bis(2,3-dihydroxypropyl)-5--2,4, 6-triiodoisophthalamide, is a nonionic, water-soluble radiographic contrast medium with a molecular weight of 821.14 (iodine content 46.36%). In aqueous solution each triiodinated molecule remains undissociated. The chemical structure is:
Iohexol and OMNIPAQUE 350 have osmolalities from approximately 2.2 to 3.0 times that of plasma (285 mOsm/kg water) or cerebrospinal fluid (301 mOsm/kg water) as shown in the above table and are hypertonic under conditions of use.
## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Iohexol in the drug label.
## Pharmacokinetics
- Iohexol is absorbed from cerebrospinal fluid (CSF) into the bloodstream and is eliminated by renal excretion. No significant metabolism, deiodination, or biotransformation occurs.
- The initial concentration and volume of the medium, in conjunction with appropriate patient manipulation and the volume of CSF into which the medium is placed, will determine the extent of the diagnostic contrast that can be achieved.
- Following intrathecal injection in conventional radiography, Iohexol will continue to provide good diagnostic contrast for at least 30 minutes. Slow diffusion of iohexol takes place throughout the CSF with subsequent absorption into the bloodstream. Once in the systemic circulation, iohexol displays little tendency to bind to serum or plasma proteins. At approximately 1 hour following injection, contrast of diagnostic quality will no longer be available for conventional myelography. If computerized tomographic (CT) myelography is to follow, consideration should be given to a delay of several hours to allow the degree of contrast to decrease.
- After administration into the lumbar subarachnoid space, computerized tomography shows the presence of contrast medium in the thoracic region in about 1 hour, in the cervical region in about 2 hours, and in the basal cisterns in 3 to 4 hours.
- In patients with renal impairment, depending on the degree of impairment, prolonged plasma iohexol levels may be anticipated due to decreased renal elimination.
## Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Iohexol in the drug label.
# Clinical Studies
There is limited information regarding Iohexol Clinical Studies in the drug label.
# How Supplied
- Iohexol
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1413-68)
- OMNIPAQUE 350
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1414-98)
- FEDERAL GOVERNMENT CODES
- Iohexol
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1413-94)
- OMNIPAQUE 350
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1414-25)
- Protect polymer bottles of OMNIPAQUE from strong daylight and direct exposure to sunlight. Do not freeze. OMNIPAQUE should be stored at controlled room temperature, 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F)
## Storage
- OMNIPAQUE Injection in all presentations may be stored in a contrast media warmer for up to one month at 37°C (98.6°F).
- SPECIAL HANDLING AND STORAGE FOR POLYMER BOTTLES ONLY: DO NOT USE IF TAMPER-EVIDENT RING IS BROKEN OR MISSING.
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
There is limited information regarding Iohexol Patient Counseling Information in the drug label.
# Precautions with Alcohol
- Alcohol-Iohexol interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- OMNIPAQUE®
# Look-Alike Drug Names
There is limited information regarding Iohexol Look-Alike Drug Names in the drug label.
# Drug Shortage Status
# Price | Iohexol
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ammu Susheela, M.D. [2]
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
# Overview
Iohexol is a contrast media that is FDA approved for the diagnosis of intrathecal administration in adults including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography (myelography, cisternography, ventriculography. Common adverse reactions include headaches, pain, nausea, vomiting and dizziness.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
- Iohexol is indicated for intrathecal administration in adults including myelography (lumbar, thoracic, cervical, total columnar) and in contrast enhancement for computerized tomography (myelography, cisternography, ventriculography).
- The volume and concentration of Iohexol to be administered will depend on the degree and extent of contrast required in the area(s) under examination and on the equipment and technique employed.
- Iohexol at a concentration of 300 mgI/mL is recommended for the examination of the lumbar, thoracic, and cervical regions in adults by lumbar or direct cervical injection and is slightly hypertonic to CSF.
- A total dose of 3060 mg iodine or a concentration of 300 mgI/mL should not be exceeded in adults in a single myelographic examination. This is based on clinical trial evaluation to date. As in all diagnostic procedures, the minimum volume and dose to produce adequate visualization should be used. Most procedures do not require either maximum dose or concentration.
- Anesthesia is not necessary. Premedication sedatives or tranquilizers are usually not needed. Patients should be well hydrated prior to and following contrast administration.
- Seizure-prone patients should be maintained on anticonvulsant medication.
- Many radiopaque contrast agents are incompatible in vitro with some antihistamines and many other drugs; therefore, concurrent drugs should not be physically admixed with contrast agents.
- To avoid excessive mixing with CSF and consequent dilution of contrast, injection should be made slowly over 1 to 2 minutes.
- Depending on the estimated volume of contrast medium which may be required for the procedure a small amount of CSF may be removed to minimize distention of the subarachnoid spaces.
- The lumbar or cervical puncture needle may be removed immediately following injection since it is not necessary to remove OMNIPAQUE after injection into the subarachnoid space.
- The usual recommended total doses for use in lumbar, thoracic, cervical, and total columnar myelography in adults are 1.2 gI to 3.0 gI as follows:
- Refer to DIRECTIONS FOR PROPER USE OF OMNIPAQUE PHARMACY BULK PACKAGE section for instructions.
- Parenteral products should be inspected visually for particulate matter or discoloration prior to administration. If particulate matter or discoloration is present, do not use.
- If in the clinical judgment of the physician sequential or repeat examinations are required, a suitable interval of time between administrations should be observed to allow for normal clearance of the drug from the body. An interval of at least 48 hours should be allowed before repeat examination; however, whenever possible, 5 to 7 days is recommended.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Iohexol in adult patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Iohexol in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Iohexol in pediatric patients.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Iohexol in pediatric patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Iohexol in pediatric patients.
# Contraindications
- OMNIPAQUE should not be administered to patients with a known hypersensitivity to iohexol.
# Warnings
- Nonionic iodinated contrast media inhibit blood coagulation, in vitro, less than ionic contrast media. Clotting has been reported when blood remains in contact with syringes containing nonionic contrast media.
- Serious, rarely fatal, thromboembolic events causing myocardial infarction and stroke have been reported during angiographic procedures with both ionic and nonionic contrast media. Therefore, meticulous intravascular administration technique is necessary, particularly during angiographic procedures, to minimize thromboembolic events. Numerous factors, including length of procedure, catheter and syringe material, underlying disease state, and concomitant medications may contribute to the development of thromboembolic events. For these reasons, meticulous angiographic techniques are recommended including close attention to guidewire and catheter manipulation, use of manifold systems and/or three-way stopcocks, frequent catheter flushing with heparinized saline solutions and minimizing the length of the procedure. The use of plastic syringes in place of glass syringes has been reported to decrease but not eliminate the likelihood of in vitro clotting.
- OMNIPAQUE should be used with extreme care in patients with severe functional disturbances of the liver and kidneys, severe thyrotoxicosis, or myelomatosis. Diabetics with a serum creatinine level above 3 mg/dL should not be examined unless the possible benefits of the examination clearly outweigh the additional risk. OMNIPAQUE is not recommended for use in patients with anuria.
- Radiopaque contrast agents are potentially hazardous in patients with multiple myeloma or other paraproteinemia, particularly in those with therapeutically resistant anuria. Although neither the contrast agent nor dehydration has separately proven to be the cause of anuria in myeloma, it has been speculated that the combination of both may be causative factors. The risk in myelomatous patients is not a contraindication; however, special precautions are necessary. Partial dehydration in the preparation of these patients prior to injection is not recommended since this may predispose the patient to precipitation of the myeloma protein in the renal tubules. No form of therapy, including dialysis, has been successful in reversing the effect. Myeloma, which occurs most commonly in persons over age 40, should be considered before instituting intravascular administration of contrast agents.
- Ionic contrast media, when injected intravenously or intra-arterially, may promote sickling in individuals who are homozygous for sickle cell disease.
- Administration of radiopaque materials to patients known or suspected of having pheochromocytoma should be performed with extreme caution. If, in the opinion of the physician, the possible benefits of such procedures outweigh the considered risks, the procedures may be performed; however, the amount of radiopaque medium injected should be kept to an absolute minimum. The patient's blood pressure should be assessed throughout the procedure and measures for the treatment of hypertensive crisis should be readily available. Reports of thyroid storm following the use of iodinated, ionic radiopaque contrast media in patients with hyperthyroidism or with an autonomously functioning thyroid nodule suggest that this additional risk be evaluated in such patients before use of any contrast medium.
- Urography should be performed with caution in patients with severely impaired renal function and patients with combined renal and hepatic disease.
# Adverse Reactions
## Clinical Trials Experience
There is limited information regarding Clinical Trial Experience of Iohexol in the drug label.
## Postmarketing Experience
- Adverse reactions following the use of Iohexol and OMNIPAQUE 350 are usually of mild to moderate severity. However, serious, life-threatening and fatal reactions, mostly of cardiovascular origin, have been associated with the administration of iodine-containing contrast media, including OMNIPAQUE.
- The injection of contrast media is frequently associated with the sensation of warmth and pain, especially in peripheral angiography; pain and warmth are less frequent and less severe with OMNIPAQUE than with many contrast media.
- Cardiovascular System
- Arrhythmias including PVCs and PACs (2%), angina/chest pain (1%), and hypotension (0.7%). Others including cardiac failure, asystole, bradycardia, tachycardia, and vasovagal reaction were reported with an individual incidence of 0.3% or less. In controlled clinical trials involving 1485 patients, one fatality occurred. A cause and effect relationship between this death and iohexol has not been established.
- Nervous System
- Vertigo (including dizziness and lightheadedness) (0.5%), pain (3%), vision abnormalities (including blurred vision and photomas) (2%), headache (2%), and taste perversion (1%). Others including anxiety, fever, motor and speech dysfunction, convulsion, paresthesia, somnolence, stiff neck, hemiparesis, syncope, shivering, transient ischemic attack, cerebral infarction, and nystagmus were reported, with an individual incidence of 0.3% or less.
- Respiratory System
- Dyspnea, rhinitis, coughing, and laryngitis, with an individual incidence of 0.2% or less.
- Gastrointestinal System
- Nausea (2%) and vomiting (0.7%). Others including diarrhea, dyspepsia, cramp, and dry mouth were reported, with an individual incidence of less than 0.1%.
- Skin and Appendages
- Urticaria (0.3%), purpura (0.1%), abscess (0.1%), and pruritus (0.1%).
- Individual adverse reactions which occurred to a significantly greater extent for a specific procedure are listed under that indication.
- In controlled clinical trials involving 391 patients for pediatric angiocardiography, urography, and contrast enhanced computed tomographic head imaging, adverse reactions following the use of Iohexol and OMNIPAQUE 350 were generally less frequent than with adults.
- Cardiovascular System
- Ventricular tachycardia (0.5%), 2:1 heart block (0.5%), hypertension (0.3%), and anemia (0.3%).
- Nervous System
- Pain (0.8%), fever (0.5%), taste abnormality (0.5%), and convulsion (0.3%).
- Respiratory System
- Congestion (0.3%) and apnea (0.3%).
- Gastrointestinal System
- Nausea (1%), hypoglycemia (0.3%), and vomiting (2%).
- Skin and Appendages
- Rash (0.3%).
- Physicians should remain alert for the occurrence of adverse effects in addition to those discussed above.
- The following reactions have been reported after administration of other intravascular iodinated contrast media, and rarely with iohexol. Reactions due to technique: hematomas and ecchymoses. Hemodynamic reactions: vein cramp and thrombophlebitis following intravenous injection. Cardiovascular reactions: rare cases of cardiac arrhythmias, reflex tachycardia, chest pain, cyanosis, hypertension, hypotension, peripheral vasodilatation, shock, and cardiac arrest. Renal reactions: occasionally, transient proteinuria and rarely, oliguria or anuria. Allergic reactions: asthmatic attacks, nasal and conjunctival symptoms, dermal reactions such as urticaria with or without pruritus, as well as pleomorphic rashes, sneezing and lacrimation and, rarely, naphylactic reactions. Rare fatalities have occurred, due to this or unknown causes. Signs and symptoms related to the respiratory system: pulmonary or laryngeal edema, bronchospasm, dyspnea; or to the nervous system: restlessness, tremors, convulsions. Other reactions: flushing, pain, warmth, metallic taste, nausea, vomiting, anxiety, headache, confusion, pallor, weakness, sweating, localized areas of edema, especially facial cramps, neutropenia, and dizziness. Rarely, immediate or delayed rigors can occur, sometimes accompanied by yperpyrexia.
- Infrequently, "iodism" (salivary gland swelling) from organic iodinated compounds appears two days after exposure and subsides by the sixth day.
- In general, the reactions which are known to occur upon parenteral administration of iodinated contrast agents are possible with any nonionic agent. Approximately 95 percent of adverse reactions accompanying the use of water-soluble intravascularly administered contrast agents are mild to moderate in degree. However, severe, life-threatening anaphylactoid reactions, mostly of cardiovascular origin, have occurred. Reported incidences of death range from 6.6 per 1 million (0.00066 percent) to 1 in 10,000 (0.01 percent). Most deaths occur during injection or 5 to 10 minutes later; the main feature being cardiac arrest with cardiovascular disease as the main aggravating factor. Isolated reports of hypotensive collapse and shock are found in the literature. The incidence of shock is estimated to be 1 out of 20,000 (0.005 percent) patients.
- Adverse reactions to injectable contrast media fall into two categories: chemotoxic reactions and idiosyncratic reactions.
- Chemotoxic reactions result from the physicochemical properties of the contrast media, the dose, and speed of injection. All hemodynamic disturbances and injuries to organs or vessels perfused by the contrast medium are included in this category.
- Idiosyncratic reactions include all other reactions. They occur more frequently in patients 20 to 40 years old. Idiosyncratic reactions may or may not be dependent on the amount of dose injected, the speed of injection, and the radiographic procedure. Idiosyncratic reactions are subdivided into minor, intermediate, and severe. The minor reactions are self-limited and of short duration; the severe reactions are life-threatening and treatment is urgent and mandatory.
- The reported incidence of adverse reactions to contrast media in patients with a history of allergy are twice that of the general population. Patients with a history of previous reactions to a contrast medium are three times more susceptible than other patients. However, sensitivity to contrast media does not appear to increase with repeated examinations.
- Most adverse reactions to injectable contrast media appear within 1 to 3 minutes after the start of injection, but delayed reactions may occur.
- Regardless of the contrast agent employed, the overall estimated incidence of serious adverse reactions is higher with angiocardiography than with other procedures. Cardiac decompensation, serious arrhythmias, angina pectoris, or myocardial ischemia or infarction may occur during angiocardiography and left ventriculography. Electrocardiographic and hemodynamic abnormalities occur less frequently with OMNIPAQUE than with diatrizoate meglumine and diatrizoate sodium injection.
- In controlled clinical trials involving 285 adult patients for various body cavity examinations using Iohexol and 350, the following adverse reactions were reported.
- Incidence > 1%: None
- Incidence ≤ 1%: Hypertension
- Incidence > 1%: Pain (26%)
- Incidence ≤ 1%: Headache, somnolence, fever, muscle weakness, burning, unwell feeling, tremors, lightheadedness, syncope
- None
- Incidence > 1%: None
- Incidence ≤ 1%: Flatulence, diarrhea, nausea, vomiting, abdominal pressure
- Incidence > 1%: Swelling (22%), heat (7%)
- Incidence ≤ 1%: Hematoma at injection site
- The most frequent reactions, pain and swelling, were almost exclusively reported after arthrography and were generally related to the procedure rather than the contrast medium. Gastrointestinal reactions were almost exclusively reported after oral pass-thru examinations.
- No adverse reactions associated with the use of OMNIPAQUE for VCU procedures were reported in 51 pediatric patients studied.
# Drug Interactions
There is limited information regarding Iohexol Drug Interactions in the drug label.
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA): B
- Reproduction studies performed in rats and rabbits at dosages up to 4.0 gI/kg and 2.5 gI/kg, respectively [2.3 and 1.4 times the maximum recommended dose for a 50 kg human, or approximately 0.4 (rat) and 0.5 (rabbit) times the maximum recommended dose for a 50 kg human following normalization of the data to body surface area estimates] have not revealed evidence of impaired fertility or harm to the fetus due to OMNIPAQUE. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Iohexol in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Iohexol during labor and delivery.
### Nursing Mothers
- It is not known to what extent iohexol is excreted in human milk. However, many injectable contrast agents are excreted unchanged in human milk. Although it has not been established that serious adverse reactions occur in nursing infants, caution should be exercised when intravascular contrast media are administered to nursing women. Bottle feedings may be substituted for breast feedings for 24 hours following administration of OMNIPAQUE.
### Pediatric Use
- Pediatric patients at higher risk of experiencing adverse events during contrast medium administration may include those having asthma, a sensitivity to medication and/or allergens, congestive heart failure, a serum creatinine greater than 1.5 mg/dL or those less than 12 months of age.
### Geriatic Use
There is no FDA guidance on the use of Iohexol with respect to geriatric patients.
### Gender
There is no FDA guidance on the use of Iohexol with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Iohexol with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Iohexol in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Iohexol in patients with hepatic impairment.
### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Iohexol in women of reproductive potentials and males.
### Immunocompromised Patients
There is no FDA guidance one the use of Iohexol in patients who are immunocompromised.
# Administration and Monitoring
### Administration
- Intrathecal
- Intravascular
- Oral
### Monitoring
- During administration of large doses of OMNIPAQUE 350, continuous monitoring of vital signs is desirable.
# IV Compatibility
There is limited information regarding IV Compatibility of Iohexol in the drug label.
# Overdosage
- Overdosage may occur. The adverse effects of overdosage are life-threatening and affect mainly the pulmonary and cardiovascular systems. The symptoms included: cyanosis, bradycardia, acidosis, pulmonary hemorrhage, convulsions, coma, and cardiac arrest. Treatment of an overdosage is directed toward the support of all vital functions, and prompt institution of symptomatic therapy.
- The intravenous LD50 values of OMNIPAQUE (in grams of iodine per kilogram body weight) are 24.2 in mice and 15.0 in rats.
# Pharmacology
## Mechanism of Action
- Following intravascular injection, iohexol is distributed in the extracellular fluid compartment and is excreted unchanged by glomerular filtration. It will opacify those vessels in the path of flow of the contrast medium permitting radiographic visualization of the internal structures until significant hemodilution occurs.
- Approximately 90% or more of the injected dose is excreted within the first 24 hours, with the peak urine concentrations occurring in the first hour after administration. Plasma and urine iohexol levels indicate that the iohexol body clearance is due primarily to renal clearance. An increase in the dose from 500 mgI/kg to 1500 mgI/kg does not significantly alter the clearance of the drug. The following pharmacokinetic values were observed following the intravenous administration of iohexol (between 500 mgI/kg to 1500 mgI/kg) to 16 adult human subjects: renal clearance—120 (86-162) mL/min; total body clearance—131 (98-165) mL/min; and volume of distribution—165 (108-219) mL/kg.
- Renal accumulation is sufficiently rapid that the period of maximal opacification of the renal passages may begin as early as 1 minute after intravenous injection. Urograms become apparent in about 1 to 3 minutes with optimal contrast occurring between 5 to 15 minutes. In nephropathic conditions, particularly when excretory capacity has been altered, the rate of excretion may vary unpredictably, and opacification may be delayed after injection. Severe renal impairment may result in a lack of diagnostic opacification of the collecting system and, depending on the degree of renal impairment, prolonged plasma iohexol levels may be anticipated. In these patients, as well as in infants with immature kidneys, the route of excretion through the gallbladder and into the small intestine may increase.
- Iohexol displays a low affinity for serum or plasma proteins and is poorly bound to serum albumin. No significant metabolism, deiodination or biotransformation occurs.
- OMNIPAQUE probably crosses the placental barrier in humans by simple diffusion. It is not known to what extent iohexol is excreted in human milk.
- Animal studies indicate that iohexol does not cross an intact blood-brain barrier to any significant extent following intravascular administration.
- OMNIPAQUE enhances computed tomographic imaging through augmentation of radiographic efficiency. The degree of density enhancement is directly related to the iodine content in an administered dose; peak iodine blood levels occur immediately following rapid intravenous injection. Blood levels fall rapidly within 5 to 10 minutes and the vascular compartment half-life is approximately 20 minutes. This can be accounted for by the dilution in the vascular and extravascular fluid compartments which causes an initial sharp fall in plasma concentration. Equilibration with the extracellular compartments is reached in about ten minutes; thereafter, the fall becomes exponential.
- The pharmacokinetics of iohexol in both normal and abnormal tissue have been shown to be variable. Contrast enhancement appears to be greatest immediately after bolus administration (15 seconds to 120 seconds). Thus, greatest enhancement may be detected by a series of consecutive two-to-three second scans performed within 30 to 90 seconds after injection (ie, dynamic computed tomographic imaging). Utilization of a continuous scanning technique (ie, dynamic CT scanning) may improve enhancement and diagnostic assessment of tumor and other lesions such as abscess, occasionally revealing unsuspected or more extensive disease. For example, a cyst may be distinguished from a vascularized solid lesion when precontrast and enhanced scans are compared; the nonperfused mass shows unchanged x-ray absorption (CT number). A vascularized lesion is characterized by an increase in CT number in the few minutes after a bolus of intravascular contrast agent; it may be malignant, benign, or normal tissue, but would probably not be a cyst, hematoma, or other nonvascular lesion.
- Because unenhanced scanning may provide adequate diagnostic information in the individual patient, the decision to employ contrast enhancement, which may be associated with risk and increased radiation exposure, should be based upon a careful evaluation of clinical, other radiological, and unenhanced CT findings.
- In contrast enhanced computed tomographic head imaging, OMNIPAQUE does not accumulate in normal brain tissue due to the presence of the normal blood-brain barrier. The increase in x-ray absorption in normal brain is due to the presence of contrast agent within the blood pool. A break in the blood-brain barrier such as occurs in malignant tumors of the brain allows for the accumulation of contrast medium within the interstitial tissue of the tumor. Adjacent normal brain tissue does not contain the contrast medium.
- Maximum contrast enhancement in tissue frequently occurs after peak blood iodine levels are reached. A delay in maximum contrast enhancement can occur. Diagnostic contrast enhanced images of the brain have been obtained up to 1 hour after intravenous bolus administration. This delay suggests that radiographic contrast enhancement is at least in part dependent on the accumulation of iodine containing medium within the lesion and outside the blood pool, although the mechanism by which this occurs is not clear. The radiographic enhancement of nontumoral lesions, such as arteriovenous malformations and aneurysms, is probably dependent on the iodine content of the circulating blood pool.
- In patients where the blood-brain barrier is known or suspected to be disrupted, the use of any radiographic contrast medium must be assessed on an individual risk to benefit basis. However, compared to ionic media, nonionic media are less toxic to the central nervous system.
- In contrast enhanced computed tomographic body imaging (nonneural tissue), OMNIPAQUE diffuses rapidly from the vascular into the extravascular space. Increase in x-ray absorption is related to blood flow, concentration of the contrast medium, and extraction of the contrast medium by interstitial tissue of tumors since no barrier exists. Contrast enhancement is thus due to the relative differences in extravascular diffusion between normal and abnormal tissue, quite different from that in the brain.
- Examinations of the uterus (hysterosalpingography) and bladder (voiding cystourethrography) involve the almost immediate drainage of contrast medium from the cavity upon conclusion of the radiographic procedure.
- Orally administered iohexol is very poorly absorbed from the normal gastrointestinal tract. Only 0.1 to 0.5 percent of the oral dose was excreted by the kidneys. This amount may increase in the presence of bowel perforation or bowel obstruction. Iohexol is well tolerated and readily absorbed if leakage into the peritoneal cavity occurs.
- Visualization of the joint spaces, uterus, fallopian tubes, peritoneal herniations, pancreatic and bile ducts, and bladder can be accomplished by direct injection of contrast medium into the region to be studied. The use of appropriate iodine concentrations assures diagnostic density.
- Orally administered OMNIPAQUE produces good visualization of the gastrointestinal tract. OMNIPAQUE is particularly useful when barium sulfate is contraindicated as in patients with suspected bowel perforation or those where aspiration of contrast medium is a possibility.
## Structure
- Iohexol, N,N´ - Bis(2,3-dihydroxypropyl)-5-[N-(2,3-dihydroxypropyl)-acetamido]-2,4, 6-triiodoisophthalamide, is a nonionic, water-soluble radiographic contrast medium with a molecular weight of 821.14 (iodine content 46.36%). In aqueous solution each triiodinated molecule remains undissociated. The chemical structure is:
Iohexol and OMNIPAQUE 350 have osmolalities from approximately 2.2 to 3.0 times that of plasma (285 mOsm/kg water) or cerebrospinal fluid (301 mOsm/kg water) as shown in the above table and are hypertonic under conditions of use.
## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Iohexol in the drug label.
## Pharmacokinetics
- Iohexol is absorbed from cerebrospinal fluid (CSF) into the bloodstream and is eliminated by renal excretion. No significant metabolism, deiodination, or biotransformation occurs.
- The initial concentration and volume of the medium, in conjunction with appropriate patient manipulation and the volume of CSF into which the medium is placed, will determine the extent of the diagnostic contrast that can be achieved.
- Following intrathecal injection in conventional radiography, Iohexol will continue to provide good diagnostic contrast for at least 30 minutes. Slow diffusion of iohexol takes place throughout the CSF with subsequent absorption into the bloodstream. Once in the systemic circulation, iohexol displays little tendency to bind to serum or plasma proteins. At approximately 1 hour following injection, contrast of diagnostic quality will no longer be available for conventional myelography. If computerized tomographic (CT) myelography is to follow, consideration should be given to a delay of several hours to allow the degree of contrast to decrease.
- After administration into the lumbar subarachnoid space, computerized tomography shows the presence of contrast medium in the thoracic region in about 1 hour, in the cervical region in about 2 hours, and in the basal cisterns in 3 to 4 hours.
- In patients with renal impairment, depending on the degree of impairment, prolonged plasma iohexol levels may be anticipated due to decreased renal elimination.
## Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Iohexol in the drug label.
# Clinical Studies
There is limited information regarding Iohexol Clinical Studies in the drug label.
# How Supplied
- Iohexol
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1413-68)
- OMNIPAQUE 350
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1414-98)
- FEDERAL GOVERNMENT CODES
- Iohexol
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1413-94)
- OMNIPAQUE 350
- 500 mL in +PLUSPAK™ (polymer bottle), boxes of 10 Pharmacy Bulk Packages
- (NDC 0407-1414-25)
- Protect polymer bottles of OMNIPAQUE from strong daylight and direct exposure to sunlight. Do not freeze. OMNIPAQUE should be stored at controlled room temperature, 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F)
## Storage
- OMNIPAQUE Injection in all presentations may be stored in a contrast media warmer for up to one month at 37°C (98.6°F).
- SPECIAL HANDLING AND STORAGE FOR POLYMER BOTTLES ONLY: DO NOT USE IF TAMPER-EVIDENT RING IS BROKEN OR MISSING.
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
There is limited information regarding Iohexol Patient Counseling Information in the drug label.
# Precautions with Alcohol
- Alcohol-Iohexol interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- OMNIPAQUE®[1]
# Look-Alike Drug Names
There is limited information regarding Iohexol Look-Alike Drug Names in the drug label.
# Drug Shortage Status
# Price | https://www.wikidoc.org/index.php/Iohexol | |
448c55162074617e686c12c2636c3d8c4d41f38b | wikidoc | Ioxilan | Ioxilan
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
# Black Box Warning
# Overview
Ioxilan is a diagnostic agent that is FDA approved for the procedure of cerebral arteriography, ventriculography, visceral angiography, aortography, and peripheral arteriography. There is a Black Box Warning for this drug as shown here. Common adverse reactions include headache, fever, chills, hypertension, bradycardia,nausea, diarrhea,vomiting and dizziness.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
# Indications
INTRAARTERIAL:
- OXILAN® Injection (300 mgI/mL) is indicated for cerebral arteriography.OXILAN® Injection (350 mgI/mL) is indicated for coronary arteriography and left ventriculography, visceral angiography, aortography, and peripheral arteriography.
INTRAVENOUS:
- OXILAN® Injection (300 mgI/mL) and OXILAN® Injection (350 mgI/mL) are indicated for excretory urography and contrast enhanced computed tomographic (CECT) imaging of the head and body.
# Dosage
ADULT DOSAGE AND ADMINISTRATION - General
- The combination of volume and OXILAN® concentration to be used should be carefully individualized accounting for factors such as age, body weight, size of the vessel and the rate of blood flow within the vessel. Specific dose adjustments for age, gender, weight, and renal function have not been studied for OXILAN®. As with all iodinated contrast agents, lower doses of OXILAN® Injection may have less risk. The efficacy of OXILAN® Injection below doses recommended has not been studied. Other factors such as anticipated pathology, degree and extent of opacification required, structure(s) or area to be examined, disease processes affecting the patient, and equipment and technique to be employed should also be considered.
- The maximum recommended total dose of iodine is 86 grams.
- If during administration a reaction occurs, the injection should be immediately stopped.
- Patients should be adequately hydrated prior to and following intravascular administration of OXILAN® Injection.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Ioxilan in adult patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Ioxilan in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
- There is limited information regarding FDA-Labeled Use of Ioxilan in pediatric patients.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Ioxilan in pediatric patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Ioxilan in pediatric patients.
# Contraindications
- OXILAN® Injection is not indicated for intrathecal use.
# Warnings
SEVERE ADVERSE EVENTS-INADVERTENT INTRATHECAL ADMINISTRATION:
- Serious adverse reactions have been reported due to the inadvertent intrathecal administration of iodinated contrast media that are not indicated for intrathecal use. These serious adverse reactions include: death, convulsions, cerebral hemorrhage, coma, paralysis, arachnoiditis, acute renal failure, cardiac arrest, seizures, rhabdomyolysis, hyperthermia, and brain edema. Special attention must be given to insure that this drug product is not administered intrathecally.
- Nonionic iodinated contrast media inhibit blood coagulation, in vitro, less than ionic contrast media. Clotting has been reported when blood remains in contact with syringes containing nonionic contrast media. The use of plastic syringes in place of glass syringes has been reported to decrease but not eliminate the likelihood of in vitro clotting.
- Serious, rarely fatal, thromboembolic events causing myocardial infarction and stroke have been reported during angiographic procedures with both ionic and nonionic contrast media. Therefore, meticulous intravascular administration technique is necessary, particularly during angiographic procedures, to minimize thromboembolic events. Numerous factors, including length of procedure, catheter and syringe material, underlying disease state, and concomitant medications may contribute to the development of thromboembolic events. For these reasons, meticulous angiographic techniques are recommended including close attention to guidewire and catheter manipulation, use of manifold systems and/or three way stopcocks, frequent catheter flushing with heparinized saline solutions, and minimizing the length of the procedure.
- Serious or fatal reactions have been associated with the administration of iodine-containing radiopaque media. It is of utmost importance to be completely prepared to treat any contrast agent reaction.
- Caution must be exercised in patients with severely impaired renal function, combined renal and hepatic disease, combined renal and cardiac disease, severe thyrotoxicosis, myelomatosis, or anuria, particularly when large doses are administered.
- Intravascularly administered iodine-containing radiopaque media are potentially hazardous in patients with multiple myeloma or other paraproteinacious diseases, who are prone to disease-induced renal insufficiency and/or failure. Although neither the contrast agent nor dehydration has been proven to be the cause of renal insufficiency (or worsening renal insufficiency) in myelomatous patients, it has been speculated that the combination of both may be causative. Special precautions, including maintenance of normal hydration and close monitoring, are required. Partial dehydration in the preparation of these patients prior to injection is not recommended since this may predispose the patient to precipitation of the myeloma protein.
- Reports of thyroid storm following the intravascular use of iodinated radiopaque agents in patients with hyperthyroidism, or with an autonomously functioning thyroid nodule, suggest that this additional risk be evaluated in such patients before use of any contrast agent.
- Administration of radiopaque materials to patients with known or suspected pheochromocytoma should be performed with extreme caution. If, in the opinion of the physician, the possible benefits of such procedures outweigh the considered risks, the procedures may be performed; however, the amount of radiopaque medium injected should be kept to an absolute minimum. The blood pressure should be assessed throughout the procedure and measures for treatment of a hypertensive crisis should be available. These patients should be monitored very closely during contrast enhanced procedures.
- Contrast agents may promote sickling in individuals who are homozygous for sickle cell disease when administered intravascularly.
# Adverse Reactions
## Clinical Trials Experience
- For demographics, see clinical trials section. The following table of incidence of reactions is based upon controlled clinical studies in which OXILAN® was compared with a nonionic contrast agent (iohexol) in 531 patients. It includes all reported adverse events, regardless of attribution. Adverse reactions are listed by body system and in decreasing order of occurrence greater than 0.5% in the OXILAN® group.
- One or more adverse reactions were reported in 76 of 531 (14.3%) of patients in the clinical trials, coincidental with the administration of OXILAN® or within the study follow-up period of 24 to 72 hours. The incidence and type of adverse reactions were similar to those associated with the nonionic comparator (iohexol) used in the clinical trials. OXILAN®, as do other iodinated contrast agents, often causes warmth and/or pain on injection. The rates are similar to that of the iohexol comparator.
- Serious, life threatening and fatal reactions have been associated with the administration of iodine-containing contrast media. In all clinical trials 3/835 (0.3%) patients given OXILAN® and 3/542 (0.6%) given iohexol died 4 days or later after drug administration. In the controlled trials 8/531 (1.5%) patients given OXILAN® and 6/542 (1.1%) given iohexol had serious adverse events.
- The following adverse reactions were observed ≤ 0.5% of patients receiving OXILAN® Injection:
- BODY: allergic reaction, asthenia, chest and back pain, edema of the neck, facial edema, pain, peripheral edema;
- CARDIOVASCULAR: atrial fibrillation, syncope, tachycardia, vasodilation, ventricular extrasystole;
- DIGESTIVE: anorexia, constipation, dyspepsia, dysphagia, GI hemorrhage, ileus, liver failure;
- NERVOUS: hypotonia, nystagmus, paresthesia, somnolence, vertigo;
- RESPIRATORY: dyspnea, pharyngitis, rhinitis;
- SKIN: pruritus, sweating;
- SPECIAL SENSES: amblyopia, conjunctivitis, taste perversion, vision abnormality;
- UROGENITAL: anuria, dysuria, hematuria, infection of urinary tract, impairment of urination, kidney failure.
## Postmarketing Experience
- Additional adverse events reported in postmarketing surveillance with the use of OXILAN® Injection include: bronchospasm.
# Drug Interactions
- Renal toxicity has been reported in a few patients with liver dysfunction who were given an oral cholecystographic agent followed by intravascular contrast agents. Administration of any intravascular contrast agent should therefore be postponed in any patient with a known or suspected hepatic or biliary disorder who has recently received a cholecystographic contrast agent.
- Other drugs should not be admixed with OXILAN® (Ioxilan Injection).
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA):
Teratogenic Effects: Pregnancy Category B
- Reproduction studies performed with ioxilan injection in rats at doses up to 6.5 gI/kg (3.7 times the recommended dose for a 50 kg human, or approximately 0.7 times the human dose following normalization of the data to body surface area estimates) and rabbits at doses up to 3.5 gI/kg (2 times the recommended dose for a 50 kg human, or approximately the same as the human dose following normalization of the data to body surface area estimates) did not reveal evidence of direct harm to the fetus. Embryolethality was not detected. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Ioxilan in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Ioxilan during labor and delivery.
### Nursing Mothers
- It is not known whether ioxilan is excreted in human milk. However, many injectable contrast agents are excreted unchanged in human milk. Although it has not been established that serious adverse reactions occur in nursing infants, caution should be exercised when intravascular contrast media are administered to nursing women because of potential adverse reactions, and consideration should be given to temporarily discontinuing nursing.
### Pediatric Use
- Safety and effectiveness in children have not been established.
### Geriatic Use
There is no FDA guidance on the use of Ioxilan with respect to geriatric patients.
### Gender
There is no FDA guidance on the use of Ioxilan with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Ioxilan with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Ioxilan in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Ioxilan in patients with hepatic impairment.
### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Ioxilan in women of reproductive potentials and males.
### Immunocompromised Patients
There is no FDA guidance one the use of Ioxilan in patients who are immunocompromised.
# Administration and Monitoring
### Administration
- Intravenous
# INTRAARTERIAL PROCEDURES
Coronary Arteriography and Left Ventriculography
- OXILAN® Injection (350 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of coronary arteries and the left ventricle. Injection rates should be approximately equal to flow rate in the vessel being injected.
- The usual individual injection volumes for visualization of the coronary arteries and the left ventricle are as follows:
- Left and Right Coronary: 2 mL to 10 mL (0.7 to 3.5 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Left Ventricle: 25 mL to 50 mL (8.75 to 17.5 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Total dose for the procedure should not usually exceed 250 mL.
- When large individual volumes are administered, as in ventriculography and aortography, it is recommended that sufficient time be permitted to elapse between each injection to allow for subsidence of possible hemodynamic disturbances.
- Mandatory prerequisites to the procedure are specialized personnel, ECG monitoring apparatus and adequate facilities for immediate resuscitation and cardioversion. Electrocardiograms and vital signs should be routinely monitored throughout the procedure.
Aortography and Selective Visceral Arteriography
- OXILAN® Injection (350 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of the aorta and major visceral arterial branches. The volume and rate of contrast injection should be proportional to the blood flow through the vessels of interest, and related to the vascular and pathological characteristics of the specific vessels being studied.
- Total dose for the procedure should not usually exceed 250 mL.
Peripheral Arteriography
- OXILAN® Injection (350 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of peripheral arteries. Injection rates should be approximately equal to flow rate in the vessel being injected. The usual individual injection volumes for visualization of various peripheral arteries are as follows:
- Aortic bifurcation for distal runoff: 45 mL to 100 mL (26 to 70 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Subclavian or femoral artery: 10 mL to 40 mL (4 to 14 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Total dose for the procedure should not usually exceed 250 mL.
- Pulsation should be present in the artery to be injected.
Cerebral Arteriography
- OXILAN® Injection (300 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of arterial lesions of the brain. The usual individual volumes per injection are 8 mL to 12 mL (2.4 to 3.6 gI) of OXILAN® Injection - 300 (300 mgI/mL).
- Total dose for the procedure should not usually exceed 150 mL.
# INTRAVENOUS PROCEDURES
Intravenous Excretory Urography
- OXILAN® Injection (300 mgI/mL or 350 mgI/mL) is indicated for intravenous injection for routine excretory urography. A volume of contrast which gives a dose of approximately 250 to 390 mgI/kg of body weight is recommended as suitable for adults with normal renal function.
- Total dose for the procedure should not usually exceed 100 mL.
Contrast Enhanced Computed Tomography
- OXILAN® Injection (300 mgI/mL or 350 mgI/mL) is indicated for intravenous injection for contrast-enhancement in the evaluation of neoplastic and non-neoplastic lesions of the head and body (intrathoracic, intraabdominal, and retroperitoneal regions).
CECT of the Head:
- The usual dose is 100 mL to 200 mL (30 to 60 gI) of OXILAN® Injection (300 mgI/mL) or 86 mL to 172 mL of OXILAN® Injection (350 mgI/mL). Scanning may be performed immediately after completion of the intravenous administration.
- Total dose for the procedure should not usually exceed 200 mL.
CECT of the Body:
- OXILAN® Injection (300 mgI/mL or 350 mgI/mL) may be administered intravenously by bolus, by rapid infusion, or by a combination of both. The usual dose is 50 mL to 200 mL (15 to 60 gI) of OXILAN(300 mgI/mL) or 43 mL to 172 mL of OXILAN® (350 mgI/mL).
- Total dose for the procedure should not usually exceed 200 mL.
# DRUG HANDLING:
- As with all contrast media, because of the potential for chemical incompatibility, OXILAN® Injection should not be mixed with, or injected in, intravenous administration lines containing other drugs, solutions, or total nutritional admixtures.
- Sterile technique must be used in all vascular injections involving contrast media.
- It is desirable that intravascularly administered iodinated contrast agents be at or close to body temperature when injected.
- If non-disposable equipment is used, scrupulous care should be taken to prevent residual contamination with traces of cleaning agents.
- Withdrawal of contrast agents from their containers should be accomplished under aseptic conditions using only sterile syringes and transfer devices. Contrast agents which have been transferred into other delivery systems should be used immediately.
- discoloration prior to administration, whenever solution and container permit. Ioxilan solutions should be used only if clear and within the normal colorless to pale yellow range.
- OXILAN® formulations are supplied in single dose containers. Discard unused portion.
Direction for proper use of OXILAN®, Pharmacy Bulk Package
- The transfer of OXILAN® (ioxilan injection) from the Pharmacy Bulk Package is restricted to a suitable work area, such as a laminar flow hood.
- The container closure may be penetrated only one time, utilizing a suitable transfer device and aseptic technique.
- The withdrawal of container contents should be accomplished without delay. However, should this not be possible, a maximum time of hours from initial closure entry is permitted to complete fluid transfer operations. The container should not be removed from the aseptic area during the entire 4 hour period.
- The temperature of the container should not exceed 30°C, after the closure has been entered.
### Monitoring
There is limited information regarding Monitoring of Ioxilan in the drug label.
# IV Compatibility
There is limited information regarding IV Compatibility of Ioxilan in the drug label.
# Overdosage
- The adverse effects of overdosage are life-threatening and affect mainly the pulmonary and cardiovascular systems. Treatment of overdosage is directed toward the support of all vital functions, and prompt institution of symptomatic therapy.
- OXILAN® Injection binds negligibly to plasma or serum protein and can, therefore, be dialyzed.
# Pharmacology
## Mechanism of Action
There is limited information regarding Ioxilan Mechanism of Action in the drug label.
## Structure
- OXILAN® (Ioxilan Injection) formulations are stable, aqueous, sterile, and non-pyrogenic solutions for intravascular administration as diagnostic radiopaque media. Ioxilan is designated chemically as N-(2,3-dihydroxypropyl)-N’-(2-hydroxyethyl)-5--2,4,6-triiodoisophthalamide and has the following structural formula:
- The molecular weight of ioxilan is 791.12 and the organically bound iodine content is 48.1%. Ioxilan is nonionic and does not dissociate in solution.
- OXILAN® (Ioxilan Injection) Pharmacy Bulk Package is available in two strengths:
- OXILAN® (Ioxilan Injection) 300 mgI/mL and OXILAN® (Ioxilan Injection) 350 mgI/mL.
- Each mL of OXILAN® (Ioxilan Injection) 300 mgI/mL provides 623 mg ioxilan.
- Each mL of OXILAN® (Ioxilan Injection) 350 mgI/mL provides 727 mg ioxilan.
- Each mL of OXILAN® (Ioxilan Injection) 300 mgI/mL Pharmacy Bulk Package provides 623 mg ioxilan.
- Each mL of OXILAN® (Ioxilan Injection) 350 mgI/mL Pharmacy Bulk Package provides 727 mg ioxilan.
- Each mL of OXILAN® solution contains 0.1 mg edetate calcium disodium (anhydrous basis), 1.0 mg tromethamine, 0.5 mg sodium chloride and a minimum of 0.2 mg (0.01 mEq) sodium. The pH is adjusted to 6.8 (5.5 to 7.5) with hydrochloric acid and sodium hydroxide. The solutions contain no preservative.
- Pertinent physicochemical data are below. OXILAN® (Ioxilan Injection) is hypertonic compared to plasma (approximately 285 mOsm/kg water).
- The OXILAN® formulations are clear, colorless to pale yellow solutions containing no undissolved solids. Crystallization does not occur at room temperature. OXILAN® solutions have osmolalities of 2.1 and 2.5 times that of plasma (285 mOsm/kg water) and are hypertonic under conditions of use.
- Each bottle of OXILAN® Pharmacy Bulk Package is to be used for dispensing multiple single dose preparations utilizing a suitable transfer device.
## Pharmacodynamics
- As with other iodinated contrast agents, following OXILAN® Injection, the degree of contrast enhancement is directly related to the iodine content in the administered dose; peak iodine plasma levels occur immediately following rapid intravenous injection. Iodine plasma levels fall rapidly within 5 to 10 minutes. This can be accounted for by the dilution in the vascular and extravascular fluid compartments.
- Intravascular Contrast: Contrast enhancement appears to be greatest immediately after bolus injections (15 seconds to 120 seconds). Thus, greatest enhancement may be detected by a series of consecutive two-to-three second scans performed within 30 to 90 seconds after injection (i.e., dynamic computed tomographic imaging).
- OXILAN® Injection may be visualized in the renal parenchyma within 30-60 seconds following rapid intravenous injection. Opacification of the calyces and pelves in patients with normal renal function becomes apparent within 1-3 minutes, with optimum contrast occurring within 5-15 minutes.
- Contrast Enhanced Computerized Tomography (CECT): AS WITH OTHER IODINATED CONTRAST AGENTS, THE USE OF OXILAN® INJECTION CONTRAST ENHANCEMENT MAY OBSCURE SOME LESIONS WHICH WERE SEEN ON PREVIOUSLY UNENHANCED CT SCANS.
- In CECT some performance characteristics are different in the brain and body. In CECT of the body, iodinated contrast agents diffuse rapidly from the vascular into the extravascular space. Following the administration of iodinated contrast agents, the increase in tissue density to x-rays is related to blood flow, the concentration of the contrast agent, and the extraction of the contrast agent by various interstitial tissues. Contrast enhancement is thus due to any relative differences in extravascular diffusion between adjacent tissues.
- In the normal brain with an intact blood-brain barrier, contrast is generally due to the presence of iodinated contrast agent within the intravascular space. The radiographic enhancement of vascular lesions, such as arteriovenous malformations and aneurysms, depends on the iodine content of the circulating blood pool.
- In tissues with a break in the blood-brain barrier, contrast agent accumulates within interstitial brain tissue. The time to maximum contrast enhancement can vary from the time that peak blood iodine levels are reached to 1 hour after intravenous bolus administration. This delay suggests that radiographic contrast enhancement is at least in part dependent on the accumulation of iodine containing medium within the lesion and outside the blood pool. The mechanism by which this occurs is not clear.
- IN PATIENTS WITH NORMAL BLOOD BRAIN BARRIERS and RENAL FAILURE, iodinated contrast agents have been associated with blood brain barrier DISRUPTION and ACCUMULATION OF CONTRAST IN THE BRAIN.
- The usefulness of contrast enhancement for the investigation of the retrobulbar space and of low grade or infiltrative glioma has not been demonstrated. Calcified lesions are less likely to enhance. The enhancement of tumors after therapy may decrease. The opacification of the inferior vermis following contrast agent administration has resulted in false-positive diagnosis. Cerebral infarctions of recent onset may be better visualized with contrast enhancement. Older infarctions are obscured by the contrast agent.
- For information on coagulation parameters, fibrinolysis and complement system, please refer to the Laboratory Test Findings section.
## Pharmacokinetics
- In healthy young (21-27 years) male (n = 4) and female volunteers (n = 4) who each received OXILAN® Injection, 72.8 g ioxilan (35.0 g iodine), the drug showed biphasic and first order pharmacokinetics. Ioxilan is distributed mainly in the blood as suggested by the apparent volume of distribution (central compartment), 7.2 ± 1.0 L in women and 10.0 ± 2.4 L in men (mean ± sd). The total clearance values were 95.4 ± 11.1 mL·min-1 and 101.0 ± 14.7 mL·min-1 and the renal clearance values were 89.4 ± 13.3 mL·min-1 and 94.9 ± 16.6 mL·min-1 for women and men, respectively. An initial fast distribution phase with a half-life of 13.1 ± 4.2 minutes (women) or 23.5 ± 15.3 minutes (men) was followed by an elimination phase with a half-life of 102.0 ± 16.9 minutes (women) and 137 ± 35.4 minutes (men). Binding of ioxilan to plasma protein is negligible.
- The average amount of ioxilan excreted unchanged in urine at 24 hours represents 93.7% of the dose in young healthy subjects (21-27 years) after intravenous administration of OXILAN® Injection. This finding suggests that, compared to the renal excretion, biliary and/or gastrointestinal excretion are not important for OXILAN®.
- The pharmacokinetics profile and total clearance of ioxilan in patients with significantly impaired renal function have not been studied. In pooled data from 80 subjects with abnormal baseline BUNS or creatinines, who received either ioxilan (n = 44) or iohexol (n = 36), there was a higher occurrence of post-procedure increased creatinine levels (p = 0.008); also, the systolic pressure was lower at 2-6 hours (p = 0.043). Dose adjustment in patients with renal failure and blood brain barrier interaction has not been studied. OXILAN® Injection binds negligibly to plasma or serum protein and can be dialyzed.
Metabolism
- There is no evidence for metabolism of OXILAN® Injection.
## Nonclinical Toxicology
- Long-term animal studies have not been performed with ioxilan to evaluate carcinogenic potential or effects on fertility. Ioxilan was not genotoxic in a series of studies including the Ames test, an in vitro human lymphocytes analysis of chromosomal aberrations, an in vivo mouse micronucleus assay, and in an in vivo mouse dominant lethal assay.
# Clinical Studies
- OXILAN® Injection was administered to 834 patients in controlled and uncontrolled studies. Of these 679 patients were between 18 and 69 years of age, and 155 patients were 70 years of age or older; the mean age was 56.4 years (range 18-88). Of the 834 patients, 579 (69%) were male and 255 (31%) were female. The racial distribution was: Caucasian 668 (80%), Black 84 (10%), Hispanic 58 (7%), Asian 14 (2%), and other or unknown 10 (1%). The demographic information for patients who received the comparator (iohexol) was similar.
- In the controlled studies, 530 patients given OXILAN® Injection and 540 patients given the comparator (iohexol) were evaluated for efficacy. Efficacy assessment was based on the global evaluation of the quality of the radiographs by rating visualization as either excellent, good, poor, or no image, and on the ability to make a diagnosis. Results were compared to those with the active control (iohexol injection) at concentrations which were identical to those of OXILAN® Injection.
- Four (4) intraarterial and three (3) intravenous procedures were studied with 1 of 2 concentrations (350 mgI/mL and 300 mgI/mL). These procedures were: aortography/visceral angiography, coronary arteriography and left ventriculography, cerebral arteriography, peripheral arteriography, contrast-enhanced computed tomography (CECT) of head and body, and excretory urography.
- Cerebral arteriography was evaluated in 3 randomized, double-blind clinical trials of OXILAN® Injection 300 mgI/mL in patients with conditions such as altered cerebrovascular perfusion and/or permeability occurring in central nervous system diseases due to various CNS disorders. Results were assessed in 78 patients with OXILAN® (Ioxilan Injection) and 83 with iohexol injection 300 mgI/mL. Visualization ratings were good or excellent in 95% of the patients with OXILAN® Injection; a radiologic diagnosis was made in the majority of the patients. The results were similar to those with iohexol injection. Confirmation of the radiologic findings by other diagnostic methods was not obtained.
- Coronary arteriography/left ventriculography was evaluated in 4 randomized, double-blind clinical trials of OXILAN® Injection 350 mgI/mL in patients with conditions such as altered coronary artery perfusion due to metabolic causes and in patients with conditions such as altered ventricular function. Results were assessed in 139 patients with OXILAN® Injection and 142 with iohexol injection 350 mgI/mL. Visualization ratings were good or excellent in 99% or more of the patients with OXILAN® Injection; a radiologic diagnosis was made in the majority of the patients. The results were similar to those with iohexol injection. Confirmation of the radiologic findings by other diagnostic methods was not obtained.
- Aortography/visceral angiography was evaluated in 3 randomized, double-blind clinical trials of OXILAN® Injection 350 mgI/mL in patients with conditions such as altered aortic blood flow and/or visceral vascular disorders. The results were assessed in 51 patients with OXILAN® Injection 350 mgI/mL and 47 with iohexol injection 350 mgI/mL. Visualization ratings were good or excellent in the majority of the patients; a radiologic diagnosis was made in 90% of the patients with OXILAN® Injection. The results were similar to those with iohexol injection. Confirmation of radiologic findings by other diagnostic methods was not obtained.
- Intravenous excretory urography was evaluated in 2 randomized, double-blind clinical trials of OXILAN® Injection 350 mgI/mL. The results were assessed in 61 patients with OXILAN® Injection 350 mgI/mL and 62 with iohexol injection 350 mgI/mL. Visualization ratings were good or excellent in all of the patients; a radiologic diagnosis was made in 100% of the patients with OXILAN® Injection. The results were similar to those with iohexol injection. Confirmation of radiologic findings by other diagnostic methods was not obtained.
- CECT of head and body was evaluated in 5 randomized, double-blind clinical trials in patients with vascular disorders. A total of 146 patients received OXILAN® Injection 300 mgI/mL and 149 received iohexol injection 300 mgI/mL. Visualization ratings were good or excellent in 98% of the patients with OXILAN® Injection; a radiologic diagnosis was made in the majority of the patients. The results were similar to those with iohexol injection.
# How Supplied
- OXILAN®(Ioxilan Injection) 300 mgI/mL
- Ten 50 mL single dose bottles, NDC 67684-1000-1
- Ten 100 mL single dose bottles, NDC 67684-1000-2
- Ten 150 mL single dose bottles, NDC 67684-1000-3
- OXILAN®(Ioxilan Injection) 350 mgI/mL
- Ten 50 mL single dose bottles, NDC 67684-1001-1
- Ten 100 mL single dose bottles, NDC 67684-1001-2
- Ten 150 mL single dose bottles, NDC 67684-1001-3
- Ten 200 mL single dose bottles, NDC 67684-1001-4
- OXILAN® (Ioxilan Injection) 300 mgI/mL Pharmacy Bulk Package - Six 500 mL bottles, NDC 67684-1000-5
- OXILAN® (Ioxilan Injection) 350 mgI/mL Pharmacy Bulk Package - Six 500 mL bottles, NDC 67684-1001-5
## Storage
- Store at room temperature between 15° and 30°C (59° and 86°F) and protect from light. Do not freeze.
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
Information for Patients:
- Patients receiving iodinated intravascular contrast agents should be instructed to:
- Inform your physician if you are pregnant.
- Inform your physician if you are diabetic or if you have multiple myeloma, pheochromocytoma, homozygous sickle cell disease, or known thyroid disorder.
- Inform your physician if you are allergic to any drugs, or food, or if you have immune, autoimmune or immune deficiency disorders. Also inform your physician if you had any reactions to previous injections of dyes used for x-ray procedures.
- Inform your physician about all medications you are currently taking, including non-prescription drugs (over-the-counter) drugs, before you have this procedure.
# Precautions with Alcohol
- Alcohol-Ioxilan interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- OXILAN®
# Look-Alike Drug Names
- A® — B®
# Drug Shortage Status
# Price | Ioxilan
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2]
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# Black Box Warning
# Overview
Ioxilan is a diagnostic agent that is FDA approved for the procedure of cerebral arteriography, ventriculography, visceral angiography, aortography, and peripheral arteriography. There is a Black Box Warning for this drug as shown here. Common adverse reactions include headache, fever, chills, hypertension, bradycardia,nausea, diarrhea,vomiting and dizziness.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
# Indications
INTRAARTERIAL:
- OXILAN® Injection (300 mgI/mL) is indicated for cerebral arteriography.OXILAN® Injection (350 mgI/mL) is indicated for coronary arteriography and left ventriculography, visceral angiography, aortography, and peripheral arteriography.
INTRAVENOUS:
- OXILAN® Injection (300 mgI/mL) and OXILAN® Injection (350 mgI/mL) are indicated for excretory urography and contrast enhanced computed tomographic (CECT) imaging of the head and body.
# Dosage
ADULT DOSAGE AND ADMINISTRATION - General
- The combination of volume and OXILAN® concentration to be used should be carefully individualized accounting for factors such as age, body weight, size of the vessel and the rate of blood flow within the vessel. Specific dose adjustments for age, gender, weight, and renal function have not been studied for OXILAN®. As with all iodinated contrast agents, lower doses of OXILAN® Injection may have less risk. The efficacy of OXILAN® Injection below doses recommended has not been studied. Other factors such as anticipated pathology, degree and extent of opacification required, structure(s) or area to be examined, disease processes affecting the patient, and equipment and technique to be employed should also be considered.
- The maximum recommended total dose of iodine is 86 grams.
- If during administration a reaction occurs, the injection should be immediately stopped.
- Patients should be adequately hydrated prior to and following intravascular administration of OXILAN® Injection.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Ioxilan in adult patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Ioxilan in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
- There is limited information regarding FDA-Labeled Use of Ioxilan in pediatric patients.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Ioxilan in pediatric patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Ioxilan in pediatric patients.
# Contraindications
- OXILAN® Injection is not indicated for intrathecal use.
# Warnings
SEVERE ADVERSE EVENTS-INADVERTENT INTRATHECAL ADMINISTRATION:
- Serious adverse reactions have been reported due to the inadvertent intrathecal administration of iodinated contrast media that are not indicated for intrathecal use. These serious adverse reactions include: death, convulsions, cerebral hemorrhage, coma, paralysis, arachnoiditis, acute renal failure, cardiac arrest, seizures, rhabdomyolysis, hyperthermia, and brain edema. Special attention must be given to insure that this drug product is not administered intrathecally.
- Nonionic iodinated contrast media inhibit blood coagulation, in vitro, less than ionic contrast media. Clotting has been reported when blood remains in contact with syringes containing nonionic contrast media. The use of plastic syringes in place of glass syringes has been reported to decrease but not eliminate the likelihood of in vitro clotting.
- Serious, rarely fatal, thromboembolic events causing myocardial infarction and stroke have been reported during angiographic procedures with both ionic and nonionic contrast media. Therefore, meticulous intravascular administration technique is necessary, particularly during angiographic procedures, to minimize thromboembolic events. Numerous factors, including length of procedure, catheter and syringe material, underlying disease state, and concomitant medications may contribute to the development of thromboembolic events. For these reasons, meticulous angiographic techniques are recommended including close attention to guidewire and catheter manipulation, use of manifold systems and/or three way stopcocks, frequent catheter flushing with heparinized saline solutions, and minimizing the length of the procedure.
- Serious or fatal reactions have been associated with the administration of iodine-containing radiopaque media. It is of utmost importance to be completely prepared to treat any contrast agent reaction.
- Caution must be exercised in patients with severely impaired renal function, combined renal and hepatic disease, combined renal and cardiac disease, severe thyrotoxicosis, myelomatosis, or anuria, particularly when large doses are administered.
- Intravascularly administered iodine-containing radiopaque media are potentially hazardous in patients with multiple myeloma or other paraproteinacious diseases, who are prone to disease-induced renal insufficiency and/or failure. Although neither the contrast agent nor dehydration has been proven to be the cause of renal insufficiency (or worsening renal insufficiency) in myelomatous patients, it has been speculated that the combination of both may be causative. Special precautions, including maintenance of normal hydration and close monitoring, are required. Partial dehydration in the preparation of these patients prior to injection is not recommended since this may predispose the patient to precipitation of the myeloma protein.
- Reports of thyroid storm following the intravascular use of iodinated radiopaque agents in patients with hyperthyroidism, or with an autonomously functioning thyroid nodule, suggest that this additional risk be evaluated in such patients before use of any contrast agent.
- Administration of radiopaque materials to patients with known or suspected pheochromocytoma should be performed with extreme caution. If, in the opinion of the physician, the possible benefits of such procedures outweigh the considered risks, the procedures may be performed; however, the amount of radiopaque medium injected should be kept to an absolute minimum. The blood pressure should be assessed throughout the procedure and measures for treatment of a hypertensive crisis should be available. These patients should be monitored very closely during contrast enhanced procedures.
- Contrast agents may promote sickling in individuals who are homozygous for sickle cell disease when administered intravascularly.
# Adverse Reactions
## Clinical Trials Experience
- For demographics, see clinical trials section. The following table of incidence of reactions is based upon controlled clinical studies in which OXILAN® was compared with a nonionic contrast agent (iohexol) in 531 patients. It includes all reported adverse events, regardless of attribution. Adverse reactions are listed by body system and in decreasing order of occurrence greater than 0.5% in the OXILAN® group.
- One or more adverse reactions were reported in 76 of 531 (14.3%) of patients in the clinical trials, coincidental with the administration of OXILAN® or within the study follow-up period of 24 to 72 hours. The incidence and type of adverse reactions were similar to those associated with the nonionic comparator (iohexol) used in the clinical trials. OXILAN®, as do other iodinated contrast agents, often causes warmth and/or pain on injection. The rates are similar to that of the iohexol comparator.
- Serious, life threatening and fatal reactions have been associated with the administration of iodine-containing contrast media. In all clinical trials 3/835 (0.3%) patients given OXILAN® and 3/542 (0.6%) given iohexol died 4 days or later after drug administration. In the controlled trials 8/531 (1.5%) patients given OXILAN® and 6/542 (1.1%) given iohexol had serious adverse events.
- The following adverse reactions were observed ≤ 0.5% of patients receiving OXILAN® Injection:
- BODY: allergic reaction, asthenia, chest and back pain, edema of the neck, facial edema, pain, peripheral edema;
- CARDIOVASCULAR: atrial fibrillation, syncope, tachycardia, vasodilation, ventricular extrasystole;
- DIGESTIVE: anorexia, constipation, dyspepsia, dysphagia, GI hemorrhage, ileus, liver failure;
- NERVOUS: hypotonia, nystagmus, paresthesia, somnolence, vertigo;
- RESPIRATORY: dyspnea, pharyngitis, rhinitis;
- SKIN: pruritus, sweating;
- SPECIAL SENSES: amblyopia, conjunctivitis, taste perversion, vision abnormality;
- UROGENITAL: anuria, dysuria, hematuria, infection of urinary tract, impairment of urination, kidney failure.
## Postmarketing Experience
- Additional adverse events reported in postmarketing surveillance with the use of OXILAN® Injection include: bronchospasm.
# Drug Interactions
- Renal toxicity has been reported in a few patients with liver dysfunction who were given an oral cholecystographic agent followed by intravascular contrast agents. Administration of any intravascular contrast agent should therefore be postponed in any patient with a known or suspected hepatic or biliary disorder who has recently received a cholecystographic contrast agent.
- Other drugs should not be admixed with OXILAN® (Ioxilan Injection).
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA):
Teratogenic Effects: Pregnancy Category B
- Reproduction studies performed with ioxilan injection in rats at doses up to 6.5 gI/kg (3.7 times the recommended dose for a 50 kg human, or approximately 0.7 times the human dose following normalization of the data to body surface area estimates) and rabbits at doses up to 3.5 gI/kg (2 times the recommended dose for a 50 kg human, or approximately the same as the human dose following normalization of the data to body surface area estimates) did not reveal evidence of direct harm to the fetus. Embryolethality was not detected. Adequate and well-controlled studies in pregnant women have not been conducted. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Pregnancy Category (AUS):
- Australian Drug Evaluation Committee (ADEC) Pregnancy Category
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Ioxilan in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Ioxilan during labor and delivery.
### Nursing Mothers
- It is not known whether ioxilan is excreted in human milk. However, many injectable contrast agents are excreted unchanged in human milk. Although it has not been established that serious adverse reactions occur in nursing infants, caution should be exercised when intravascular contrast media are administered to nursing women because of potential adverse reactions, and consideration should be given to temporarily discontinuing nursing.
### Pediatric Use
- Safety and effectiveness in children have not been established.
### Geriatic Use
There is no FDA guidance on the use of Ioxilan with respect to geriatric patients.
### Gender
There is no FDA guidance on the use of Ioxilan with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Ioxilan with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Ioxilan in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Ioxilan in patients with hepatic impairment.
### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Ioxilan in women of reproductive potentials and males.
### Immunocompromised Patients
There is no FDA guidance one the use of Ioxilan in patients who are immunocompromised.
# Administration and Monitoring
### Administration
- Intravenous
# INTRAARTERIAL PROCEDURES
Coronary Arteriography and Left Ventriculography
- OXILAN® Injection (350 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of coronary arteries and the left ventricle. Injection rates should be approximately equal to flow rate in the vessel being injected.
- The usual individual injection volumes for visualization of the coronary arteries and the left ventricle are as follows:
- Left and Right Coronary: 2 mL to 10 mL (0.7 to 3.5 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Left Ventricle: 25 mL to 50 mL (8.75 to 17.5 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Total dose for the procedure should not usually exceed 250 mL.
- When large individual volumes are administered, as in ventriculography and aortography, it is recommended that sufficient time be permitted to elapse between each injection to allow for subsidence of possible hemodynamic disturbances.
- Mandatory prerequisites to the procedure are specialized personnel, ECG monitoring apparatus and adequate facilities for immediate resuscitation and cardioversion. Electrocardiograms and vital signs should be routinely monitored throughout the procedure.
Aortography and Selective Visceral Arteriography
- OXILAN® Injection (350 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of the aorta and major visceral arterial branches. The volume and rate of contrast injection should be proportional to the blood flow through the vessels of interest, and related to the vascular and pathological characteristics of the specific vessels being studied.
- Total dose for the procedure should not usually exceed 250 mL.
Peripheral Arteriography
- OXILAN® Injection (350 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of peripheral arteries. Injection rates should be approximately equal to flow rate in the vessel being injected. The usual individual injection volumes for visualization of various peripheral arteries are as follows:
- Aortic bifurcation for distal runoff: 45 mL to 100 mL (26 to 70 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Subclavian or femoral artery: 10 mL to 40 mL (4 to 14 gI) of OXILAN® Injection - 350 (350 mgI/mL)
- Total dose for the procedure should not usually exceed 250 mL.
- Pulsation should be present in the artery to be injected.
Cerebral Arteriography
- OXILAN® Injection (300 mgI/mL) is indicated for intraarterial injection in the radiographic contrast evaluation of arterial lesions of the brain. The usual individual volumes per injection are 8 mL to 12 mL (2.4 to 3.6 gI) of OXILAN® Injection - 300 (300 mgI/mL).
- Total dose for the procedure should not usually exceed 150 mL.
# INTRAVENOUS PROCEDURES
Intravenous Excretory Urography
- OXILAN® Injection (300 mgI/mL or 350 mgI/mL) is indicated for intravenous injection for routine excretory urography. A volume of contrast which gives a dose of approximately 250 to 390 mgI/kg of body weight is recommended as suitable for adults with normal renal function.
- Total dose for the procedure should not usually exceed 100 mL.
Contrast Enhanced Computed Tomography
- OXILAN® Injection (300 mgI/mL or 350 mgI/mL) is indicated for intravenous injection for contrast-enhancement in the evaluation of neoplastic and non-neoplastic lesions of the head and body (intrathoracic, intraabdominal, and retroperitoneal regions).
CECT of the Head:
- The usual dose is 100 mL to 200 mL (30 to 60 gI) of OXILAN® Injection (300 mgI/mL) or 86 mL to 172 mL of OXILAN® Injection (350 mgI/mL). Scanning may be performed immediately after completion of the intravenous administration.
- Total dose for the procedure should not usually exceed 200 mL.
CECT of the Body:
- OXILAN® Injection (300 mgI/mL or 350 mgI/mL) may be administered intravenously by bolus, by rapid infusion, or by a combination of both. The usual dose is 50 mL to 200 mL (15 to 60 gI) of OXILAN(300 mgI/mL) or 43 mL to 172 mL of OXILAN® (350 mgI/mL).
- Total dose for the procedure should not usually exceed 200 mL.
# DRUG HANDLING:
- As with all contrast media, because of the potential for chemical incompatibility, OXILAN® Injection should not be mixed with, or injected in, intravenous administration lines containing other drugs, solutions, or total nutritional admixtures.
- Sterile technique must be used in all vascular injections involving contrast media.
- It is desirable that intravascularly administered iodinated contrast agents be at or close to body temperature when injected.
- If non-disposable equipment is used, scrupulous care should be taken to prevent residual contamination with traces of cleaning agents.
- Withdrawal of contrast agents from their containers should be accomplished under aseptic conditions using only sterile syringes and transfer devices. Contrast agents which have been transferred into other delivery systems should be used immediately.
- discoloration prior to administration, whenever solution and container permit. Ioxilan solutions should be used only if clear and within the normal colorless to pale yellow range.
- OXILAN® formulations are supplied in single dose containers. Discard unused portion.
Direction for proper use of OXILAN®, Pharmacy Bulk Package
- The transfer of OXILAN® (ioxilan injection) from the Pharmacy Bulk Package is restricted to a suitable work area, such as a laminar flow hood.
- The container closure may be penetrated only one time, utilizing a suitable transfer device and aseptic technique.
- The withdrawal of container contents should be accomplished without delay. However, should this not be possible, a maximum time of [4] hours from initial closure entry is permitted to complete fluid transfer operations. The container should not be removed from the aseptic area during the entire 4 hour period.
- The temperature of the container should not exceed 30°C, after the closure has been entered.
### Monitoring
There is limited information regarding Monitoring of Ioxilan in the drug label.
# IV Compatibility
There is limited information regarding IV Compatibility of Ioxilan in the drug label.
# Overdosage
- The adverse effects of overdosage are life-threatening and affect mainly the pulmonary and cardiovascular systems. Treatment of overdosage is directed toward the support of all vital functions, and prompt institution of symptomatic therapy.
- OXILAN® Injection binds negligibly to plasma or serum protein and can, therefore, be dialyzed.
# Pharmacology
## Mechanism of Action
There is limited information regarding Ioxilan Mechanism of Action in the drug label.
## Structure
- OXILAN® (Ioxilan Injection) formulations are stable, aqueous, sterile, and non-pyrogenic solutions for intravascular administration as diagnostic radiopaque media. Ioxilan is designated chemically as N-(2,3-dihydroxypropyl)-N’-(2-hydroxyethyl)-5-[N-(2,3-dihydroxypropyl) acetamido]-2,4,6-triiodoisophthalamide and has the following structural formula:
- The molecular weight of ioxilan is 791.12 and the organically bound iodine content is 48.1%. Ioxilan is nonionic and does not dissociate in solution.
- OXILAN® (Ioxilan Injection) Pharmacy Bulk Package is available in two strengths:
- OXILAN® (Ioxilan Injection) 300 mgI/mL and OXILAN® (Ioxilan Injection) 350 mgI/mL.
- Each mL of OXILAN® (Ioxilan Injection) 300 mgI/mL provides 623 mg ioxilan.
- Each mL of OXILAN® (Ioxilan Injection) 350 mgI/mL provides 727 mg ioxilan.
- Each mL of OXILAN® (Ioxilan Injection) 300 mgI/mL Pharmacy Bulk Package provides 623 mg ioxilan.
- Each mL of OXILAN® (Ioxilan Injection) 350 mgI/mL Pharmacy Bulk Package provides 727 mg ioxilan.
- Each mL of OXILAN® solution contains 0.1 mg edetate calcium disodium (anhydrous basis), 1.0 mg tromethamine, 0.5 mg sodium chloride and a minimum of 0.2 mg (0.01 mEq) sodium. The pH is adjusted to 6.8 (5.5 to 7.5) with hydrochloric acid and sodium hydroxide. The solutions contain no preservative.
- Pertinent physicochemical data are below. OXILAN® (Ioxilan Injection) is hypertonic compared to plasma (approximately 285 mOsm/kg water).
- The OXILAN® formulations are clear, colorless to pale yellow solutions containing no undissolved solids. Crystallization does not occur at room temperature. OXILAN® solutions have osmolalities of 2.1 and 2.5 times that of plasma (285 mOsm/kg water) and are hypertonic under conditions of use.
- Each bottle of OXILAN® Pharmacy Bulk Package is to be used for dispensing multiple single dose preparations utilizing a suitable transfer device.
## Pharmacodynamics
- As with other iodinated contrast agents, following OXILAN® Injection, the degree of contrast enhancement is directly related to the iodine content in the administered dose; peak iodine plasma levels occur immediately following rapid intravenous injection. Iodine plasma levels fall rapidly within 5 to 10 minutes. This can be accounted for by the dilution in the vascular and extravascular fluid compartments.
- Intravascular Contrast: Contrast enhancement appears to be greatest immediately after bolus injections (15 seconds to 120 seconds). Thus, greatest enhancement may be detected by a series of consecutive two-to-three second scans performed within 30 to 90 seconds after injection (i.e., dynamic computed tomographic imaging).
- OXILAN® Injection may be visualized in the renal parenchyma within 30-60 seconds following rapid intravenous injection. Opacification of the calyces and pelves in patients with normal renal function becomes apparent within 1-3 minutes, with optimum contrast occurring within 5-15 minutes.
- Contrast Enhanced Computerized Tomography (CECT): AS WITH OTHER IODINATED CONTRAST AGENTS, THE USE OF OXILAN® INJECTION CONTRAST ENHANCEMENT MAY OBSCURE SOME LESIONS WHICH WERE SEEN ON PREVIOUSLY UNENHANCED CT SCANS.
- In CECT some performance characteristics are different in the brain and body. In CECT of the body, iodinated contrast agents diffuse rapidly from the vascular into the extravascular space. Following the administration of iodinated contrast agents, the increase in tissue density to x-rays is related to blood flow, the concentration of the contrast agent, and the extraction of the contrast agent by various interstitial tissues. Contrast enhancement is thus due to any relative differences in extravascular diffusion between adjacent tissues.
- In the normal brain with an intact blood-brain barrier, contrast is generally due to the presence of iodinated contrast agent within the intravascular space. The radiographic enhancement of vascular lesions, such as arteriovenous malformations and aneurysms, depends on the iodine content of the circulating blood pool.
- In tissues with a break in the blood-brain barrier, contrast agent accumulates within interstitial brain tissue. The time to maximum contrast enhancement can vary from the time that peak blood iodine levels are reached to 1 hour after intravenous bolus administration. This delay suggests that radiographic contrast enhancement is at least in part dependent on the accumulation of iodine containing medium within the lesion and outside the blood pool. The mechanism by which this occurs is not clear.
- IN PATIENTS WITH NORMAL BLOOD BRAIN BARRIERS and RENAL FAILURE, iodinated contrast agents have been associated with blood brain barrier DISRUPTION and ACCUMULATION OF CONTRAST IN THE BRAIN.
- The usefulness of contrast enhancement for the investigation of the retrobulbar space and of low grade or infiltrative glioma has not been demonstrated. Calcified lesions are less likely to enhance. The enhancement of tumors after therapy may decrease. The opacification of the inferior vermis following contrast agent administration has resulted in false-positive diagnosis. Cerebral infarctions of recent onset may be better visualized with contrast enhancement. Older infarctions are obscured by the contrast agent.
- For information on coagulation parameters, fibrinolysis and complement system, please refer to the Laboratory Test Findings section.
## Pharmacokinetics
- In healthy young (21-27 years) male (n = 4) and female volunteers (n = 4) who each received OXILAN® Injection, 72.8 g ioxilan (35.0 g iodine), the drug showed biphasic and first order pharmacokinetics. Ioxilan is distributed mainly in the blood as suggested by the apparent volume of distribution (central compartment), 7.2 ± 1.0 L in women and 10.0 ± 2.4 L in men (mean ± sd). The total clearance values were 95.4 ± 11.1 mL·min-1 and 101.0 ± 14.7 mL·min-1 and the renal clearance values were 89.4 ± 13.3 mL·min-1 and 94.9 ± 16.6 mL·min-1 for women and men, respectively. An initial fast distribution phase with a half-life of 13.1 ± 4.2 minutes (women) or 23.5 ± 15.3 minutes (men) was followed by an elimination phase with a half-life of 102.0 ± 16.9 minutes (women) and 137 ± 35.4 minutes (men). Binding of ioxilan to plasma protein is negligible.
- The average amount of ioxilan excreted unchanged in urine at 24 hours represents 93.7% of the dose in young healthy subjects (21-27 years) after intravenous administration of OXILAN® Injection. This finding suggests that, compared to the renal excretion, biliary and/or gastrointestinal excretion are not important for OXILAN®.
- The pharmacokinetics profile and total clearance of ioxilan in patients with significantly impaired renal function have not been studied. In pooled data from 80 subjects with abnormal baseline BUNS or creatinines, who received either ioxilan (n = 44) or iohexol (n = 36), there was a higher occurrence of post-procedure increased creatinine levels (p = 0.008); also, the systolic pressure was lower at 2-6 hours (p = 0.043). Dose adjustment in patients with renal failure and blood brain barrier interaction has not been studied. OXILAN® Injection binds negligibly to plasma or serum protein and can be dialyzed.
Metabolism
- There is no evidence for metabolism of OXILAN® Injection.
## Nonclinical Toxicology
- Long-term animal studies have not been performed with ioxilan to evaluate carcinogenic potential or effects on fertility. Ioxilan was not genotoxic in a series of studies including the Ames test, an in vitro human lymphocytes analysis of chromosomal aberrations, an in vivo mouse micronucleus assay, and in an in vivo mouse dominant lethal assay.
# Clinical Studies
- OXILAN® Injection was administered to 834 patients in controlled and uncontrolled studies. Of these 679 patients were between 18 and 69 years of age, and 155 patients were 70 years of age or older; the mean age was 56.4 years (range 18-88). Of the 834 patients, 579 (69%) were male and 255 (31%) were female. The racial distribution was: Caucasian 668 (80%), Black 84 (10%), Hispanic 58 (7%), Asian 14 (2%), and other or unknown 10 (1%). The demographic information for patients who received the comparator (iohexol) was similar.
- In the controlled studies, 530 patients given OXILAN® Injection and 540 patients given the comparator (iohexol) were evaluated for efficacy. Efficacy assessment was based on the global evaluation of the quality of the radiographs by rating visualization as either excellent, good, poor, or no image, and on the ability to make a diagnosis. Results were compared to those with the active control (iohexol injection) at concentrations which were identical to those of OXILAN® Injection.
- Four (4) intraarterial and three (3) intravenous procedures were studied with 1 of 2 concentrations (350 mgI/mL and 300 mgI/mL). These procedures were: aortography/visceral angiography, coronary arteriography and left ventriculography, cerebral arteriography, peripheral arteriography, contrast-enhanced computed tomography (CECT) of head and body, and excretory urography.
- Cerebral arteriography was evaluated in 3 randomized, double-blind clinical trials of OXILAN® Injection 300 mgI/mL in patients with conditions such as altered cerebrovascular perfusion and/or permeability occurring in central nervous system diseases due to various CNS disorders. Results were assessed in 78 patients with OXILAN® (Ioxilan Injection) and 83 with iohexol injection 300 mgI/mL. Visualization ratings were good or excellent in 95% of the patients with OXILAN® Injection; a radiologic diagnosis was made in the majority of the patients. The results were similar to those with iohexol injection. Confirmation of the radiologic findings by other diagnostic methods was not obtained.
- Coronary arteriography/left ventriculography was evaluated in 4 randomized, double-blind clinical trials of OXILAN® Injection 350 mgI/mL in patients with conditions such as altered coronary artery perfusion due to metabolic causes and in patients with conditions such as altered ventricular function. Results were assessed in 139 patients with OXILAN® Injection and 142 with iohexol injection 350 mgI/mL. Visualization ratings were good or excellent in 99% or more of the patients with OXILAN® Injection; a radiologic diagnosis was made in the majority of the patients. The results were similar to those with iohexol injection. Confirmation of the radiologic findings by other diagnostic methods was not obtained.
- Aortography/visceral angiography was evaluated in 3 randomized, double-blind clinical trials of OXILAN® Injection 350 mgI/mL in patients with conditions such as altered aortic blood flow and/or visceral vascular disorders. The results were assessed in 51 patients with OXILAN® Injection 350 mgI/mL and 47 with iohexol injection 350 mgI/mL. Visualization ratings were good or excellent in the majority of the patients; a radiologic diagnosis was made in 90% of the patients with OXILAN® Injection. The results were similar to those with iohexol injection. Confirmation of radiologic findings by other diagnostic methods was not obtained.
- Intravenous excretory urography was evaluated in 2 randomized, double-blind clinical trials of OXILAN® Injection 350 mgI/mL. The results were assessed in 61 patients with OXILAN® Injection 350 mgI/mL and 62 with iohexol injection 350 mgI/mL. Visualization ratings were good or excellent in all of the patients; a radiologic diagnosis was made in 100% of the patients with OXILAN® Injection. The results were similar to those with iohexol injection. Confirmation of radiologic findings by other diagnostic methods was not obtained.
- CECT of head and body was evaluated in 5 randomized, double-blind clinical trials in patients with vascular disorders. A total of 146 patients received OXILAN® Injection 300 mgI/mL and 149 received iohexol injection 300 mgI/mL. Visualization ratings were good or excellent in 98% of the patients with OXILAN® Injection; a radiologic diagnosis was made in the majority of the patients. The results were similar to those with iohexol injection.
# How Supplied
- OXILAN®(Ioxilan Injection) 300 mgI/mL
- Ten 50 mL single dose bottles, NDC 67684-1000-1
- Ten 100 mL single dose bottles, NDC 67684-1000-2
- Ten 150 mL single dose bottles, NDC 67684-1000-3
- OXILAN®(Ioxilan Injection) 350 mgI/mL
- Ten 50 mL single dose bottles, NDC 67684-1001-1
- Ten 100 mL single dose bottles, NDC 67684-1001-2
- Ten 150 mL single dose bottles, NDC 67684-1001-3
- Ten 200 mL single dose bottles, NDC 67684-1001-4
- OXILAN® (Ioxilan Injection) 300 mgI/mL Pharmacy Bulk Package - Six 500 mL bottles, NDC 67684-1000-5
- OXILAN® (Ioxilan Injection) 350 mgI/mL Pharmacy Bulk Package - Six 500 mL bottles, NDC 67684-1001-5
## Storage
- Store at room temperature between 15° and 30°C (59° and 86°F) and protect from light. Do not freeze.
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
Information for Patients:
- Patients receiving iodinated intravascular contrast agents should be instructed to:
- Inform your physician if you are pregnant.
- Inform your physician if you are diabetic or if you have multiple myeloma, pheochromocytoma, homozygous sickle cell disease, or known thyroid disorder.
- Inform your physician if you are allergic to any drugs, or food, or if you have immune, autoimmune or immune deficiency disorders. Also inform your physician if you had any reactions to previous injections of dyes used for x-ray procedures.
- Inform your physician about all medications you are currently taking, including non-prescription drugs (over-the-counter) drugs, before you have this procedure.
# Precautions with Alcohol
- Alcohol-Ioxilan interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- OXILAN®[1]
# Look-Alike Drug Names
- A® — B®[2]
# Drug Shortage Status
# Price | https://www.wikidoc.org/index.php/Ioxilan | |
f5d8cd99a7d47ec682c19e72abde5894798d5982 | wikidoc | Ipomoea | Ipomoea
# Overview
Ipomoea /ˌɪpˈmiːə/ is the largest genus in the flowering plant family Convolvulaceae, with over 500 species. It is a large and diverse group with common names including morning glory, sweet potato, bindweed, moonflower, etc.
The most widespread common name is morning glories, but there are also species in related genera bearing the same common name. Those formerly separated in Calonyction (Greek καλός, kalos, good and νύκτα, nycta, night) are called moonflowers. The generic name is derived from the Greek words ιπς (ips) or ιπος (ipos), meaning "worm" or "bindweed," and όμοιος (homoios), meaning "resembling". It refers to their twining habit. The genus occurs throughout the tropical and subtropical regions of the world, and comprises annual and perennial herbaceous plants, lianas, shrubs and small trees; most of the species are twining climbing plants.
# Uses and ecology
Human use of Ipomoea include:
- Most species have spectacular, colorful flowers and are often grown as ornamentals, and a number of cultivars have been developed. Their deep flowers attract large Lepidoptera - especially Sphingidae such as the pink-spotted hawk moth (Agrius cingulata) - or even hummingbirds.
- The genus includes food crops; the tubers of sweet potatoes (Ipomoea batatas) and the leaves of water spinach (I. aquatica) are commercially important food items and have been for millennia. The sweet potato is one of the Polynesian "canoe plants", transplanted by settlers on islands throughout the Pacific. Water spinach is used all over eastern Asia and the warmer regions of the Americas as a key component of well-known dishes, such as Canh chua rau muống (Mekong sour soup) or callaloo; its numerous local names attest to its popularity. Other species are used on a smaller scale, e.g. the whitestar potato (I. lacunosa) traditionally eaten by some Native Americans, such as the Chiricahua Apaches, or the Australian bush potato (I. costata).
- Peonidin, an anthocyanidin potentially useful as a food additive, is present in significant quantities in the flowers of the 'Heavenly Blue' cultivars.
- Moon vine (I. alba) sap was used for vulcanization of the latex of Castilla elastica (Panama rubber tree, Nahuatl: olicuáhuitl) to rubber; as it happens, the rubber tree seems well-suited for the vine to twine upon, and the two species are often found together. As early as 1600 BCE, the Olmecs produced the balls used in the Mesoamerican ballgame.
- The root called John the Conqueror in hoodoo and used in lucky and/or sexual charms (though apparently not as a component of love potions, because it is a strong laxative if ingested) usually seems to be from I. jalapa. The testicle-like dried tubers are carried as amulets and rubbed by the users to gain good luck in gambling or flirting. As Willie Dixon wrote, somewhat tongue-in-cheek, in his song "Rub My Root" (a Muddy Waters version is titled "My John the Conquer Root"):
## As medicine and entheogen
Humans use Ipomoea for their content of medical and psychoactive compounds, mainly alkaloids. Some species are renowned for their properties in folk medicine and herbalism; for example Vera Cruz jalap (I. jalapa) and Tampico jalap (I. simulans) are used to produce jalap, a cathartic preparation accelerating the passage of stool. Kiribadu Ala (giant potato, I. mauritiana) is one of the many ingredients of chyawanprash, the ancient Ayurvedic tonic called "the elixir of life" for its wide-ranging properties.
The leaves of I. batatas are eaten as a vegetable, and have been shown to slow oxygenation of LDLs, with some similar potential health benefits to green tea and grape polyphenols.
Other species were and still are used as potent entheogens. Seeds of Mexican morning glory (tlitliltzin, I. tricolor) were thus used by Aztecs and Zapotecs in shamanistic and priestly divination rituals, and at least by the former also as a poison, to give the victim a "horror trip" (see also Aztec entheogenic complex). Beach moonflower (I. violacea) was also used thus, and the cultivars called 'Heavenly Blue Morning Glory', touted today for their psychoactive properties, seem to represent an indeterminable assembly of hybrids of these two species.
Ergoline derivatives (lysergamides) are probably responsible for the entheogenic activity. Ergine (LSA), isoergine, D-lysergic acid N-(α-hydroxyethyl)amide and lysergol have been isolated from I. tricolor, I. violacea and/or purple morning glory (I. purpurea); although these are often assumed to be the cause of the plants' effects, this is not supported by scientific studies, which show although they are psychoactive, they are not notably hallucinogenic. Alexander Shulgin in TiHKAL suggests ergonovine is responsible, instead. It has verified psychoactive properties, though as yet other undiscovered lysergamides possibly are present in the seeds.
Though most often noted as "recreational" drugs, the lysergamides are also of medical importance. Ergonovine enhances the action of oxytocin, used to still post partum bleeding. Ergine induces drowsiness and a relaxed state and might be useful in treating anxiety disorder. Whether Ipomoea species are a useful source of these compounds remains to be determined. In any case, in some jurisdictions certain Ipomoea are regulated, e.g. by the Louisiana State Act 159 which bans cultivation of I. violacea except for ornamental purposes.
## Pests and diseases
Many herbivores avoid morning glories such as Ipomoea, as the high alkaloid content makes these plants unpalatable, if not toxic. Nonetheless, Ipomoea species are used as food plants by the caterpillars of certain Lepidoptera (butterflies and moths); see list of Lepidoptera which feed on Ipomoea. For a selection of diseases of the sweet potato (I. batatas), many of which also infect other members of this genus, see List of sweet potato diseases. | Ipomoea
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Ipomoea /ˌɪp[invalid input: 'ɵ']ˈmiːə/[1] is the largest genus in the flowering plant family Convolvulaceae, with over 500 species. It is a large and diverse group with common names including morning glory, sweet potato, bindweed, moonflower, etc.
The most widespread common name is morning glories, but there are also species in related genera bearing the same common name. Those formerly separated in Calonyction (Greek καλός, kalos, good and νύκτα, nycta, night) are called moonflowers. The generic name is derived from the Greek words ιπς (ips) or ιπος (ipos), meaning "worm" or "bindweed," and όμοιος (homoios), meaning "resembling". It refers to their twining habit.[2] The genus occurs throughout the tropical and subtropical regions of the world, and comprises annual and perennial herbaceous plants, lianas, shrubs and small trees; most of the species are twining climbing plants.
# Uses and ecology
Human use of Ipomoea include:
- Most species have spectacular, colorful flowers and are often grown as ornamentals, and a number of cultivars have been developed. Their deep flowers attract large Lepidoptera - especially Sphingidae such as the pink-spotted hawk moth (Agrius cingulata) - or even hummingbirds.
- The genus includes food crops; the tubers of sweet potatoes (Ipomoea batatas) and the leaves of water spinach (I. aquatica) are commercially important food items and have been for millennia. The sweet potato is one of the Polynesian "canoe plants", transplanted by settlers on islands throughout the Pacific. Water spinach is used all over eastern Asia and the warmer regions of the Americas as a key component of well-known dishes, such as Canh chua rau muống (Mekong sour soup) or callaloo; its numerous local names attest to its popularity. Other species are used on a smaller scale, e.g. the whitestar potato (I. lacunosa) traditionally eaten by some Native Americans, such as the Chiricahua Apaches, or the Australian bush potato (I. costata).
- Peonidin, an anthocyanidin potentially useful as a food additive, is present in significant quantities in the flowers of the 'Heavenly Blue' cultivars.
- Moon vine (I. alba) sap was used for vulcanization of the latex of Castilla elastica (Panama rubber tree, Nahuatl: olicuáhuitl) to rubber; as it happens, the rubber tree seems well-suited for the vine to twine upon, and the two species are often found together. As early as 1600 BCE, the Olmecs produced the balls used in the Mesoamerican ballgame.[3]
- The root called John the Conqueror in hoodoo and used in lucky and/or sexual charms (though apparently not as a component of love potions, because it is a strong laxative if ingested) usually seems to be from I. jalapa. The testicle-like dried tubers are carried as amulets and rubbed by the users to gain good luck in gambling or flirting. As Willie Dixon wrote, somewhat tongue-in-cheek, in his song "Rub My Root" (a Muddy Waters version is titled "My John the Conquer Root"):
## As medicine and entheogen
Humans use Ipomoea for their content of medical and psychoactive compounds, mainly alkaloids. Some species are renowned for their properties in folk medicine and herbalism; for example Vera Cruz jalap (I. jalapa) and Tampico jalap (I. simulans) are used to produce jalap, a cathartic preparation accelerating the passage of stool. Kiribadu Ala (giant potato, I. mauritiana) is one of the many ingredients of chyawanprash, the ancient Ayurvedic tonic called "the elixir of life" for its wide-ranging properties.
The leaves of I. batatas are eaten as a vegetable, and have been shown to slow oxygenation of LDLs, with some similar potential health benefits to green tea and grape polyphenols.[4]
Other species were and still are used as potent entheogens. Seeds of Mexican morning glory (tlitliltzin, I. tricolor) were thus used by Aztecs and Zapotecs in shamanistic and priestly divination rituals, and at least by the former also as a poison, to give the victim a "horror trip" (see also Aztec entheogenic complex). Beach moonflower (I. violacea) was also used thus, and the cultivars called 'Heavenly Blue Morning Glory', touted today for their psychoactive properties, seem to represent an indeterminable assembly of hybrids of these two species.
Ergoline derivatives (lysergamides) are probably responsible for the entheogenic activity. Ergine (LSA), isoergine, D-lysergic acid N-(α-hydroxyethyl)amide and lysergol have been isolated from I. tricolor, I. violacea and/or purple morning glory (I. purpurea); although these are often assumed to be the cause of the plants' effects, this is not supported by scientific studies, which show although they are psychoactive, they are not notably hallucinogenic.[citation needed] Alexander Shulgin in TiHKAL suggests ergonovine is responsible, instead. It has verified psychoactive properties, though as yet other undiscovered lysergamides possibly are present in the seeds.
Though most often noted as "recreational" drugs, the lysergamides are also of medical importance. Ergonovine enhances the action of oxytocin, used to still post partum bleeding. Ergine induces drowsiness and a relaxed state and might be useful in treating anxiety disorder. Whether Ipomoea species are a useful source of these compounds remains to be determined. In any case, in some jurisdictions certain Ipomoea are regulated, e.g. by the Louisiana State Act 159 which bans cultivation of I. violacea except for ornamental purposes.
## Pests and diseases
Many herbivores avoid morning glories such as Ipomoea, as the high alkaloid content makes these plants unpalatable, if not toxic. Nonetheless, Ipomoea species are used as food plants by the caterpillars of certain Lepidoptera (butterflies and moths); see list of Lepidoptera which feed on Ipomoea. For a selection of diseases of the sweet potato (I. batatas), many of which also infect other members of this genus, see List of sweet potato diseases. | https://www.wikidoc.org/index.php/Ipomoea | |
47d04b07e7a55b9c1229e96ed57307a37b222db1 | wikidoc | Isozyme | Isozyme
# Overview
Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes usually display different kinetic parameters (i.e. different KM values), or different regulatory properties.
The existence of isozymes permits the fine-tuning of metabolism to meet the particular needs of a given tissue or developmental stage (for example lactate dehydrogenase (LDH)).
In biochemistry, isozymes (or isoenzymes) are isoforms (closely related variants) of enzymes. In many cases, they are coded for by homologous genes that have diverged over time. Although, strictly speaking, allozymes represent enzymes from different alleles of the same gene, and isozymes represent enzymes from different genes whose products catalyse the same reaction, the two words are usually used interchangeably.
# Introduction
Isozymes were first described by R. L. Hunter and Clement Markert (1957) who defined them as different variants of the same enzyme having identical functions and present in the same individual. This definition encompasses (1) enzyme variants that are the product of different genes and thus represent different loci (described as isozymes) and (2) enzymes that are the product of different alleles of the same gene (described as allozymes).
Isozymes are usually the result of gene duplication, but can also arise from polyploidisation or nucleic acid hybridization. Over evolutionary time, if the function of the new variant remains identical to the original, then it is likely that one or the other will be lost as mutations accumulate, resulting in a pseudogene. However, if the mutations do not immediately prevent the enzyme from functioning, but instead modify either its function, or its pattern of gene expression, then the two variants may both be favoured by natural selection and become specialised to different functions. For example, they may be expressed at different stages of development or in different tissues.
Allozymes may result from point mutations or from insertion-deletion (indel) events that affect the DNA coding sequence of the gene. As with any other new mutation, there are three things that may happen to a new allozyme:
- It is most likely that the new allele will be non-functional — in which case it will probably result in low fitness and be removed from the population by natural selection.
- Alternatively, if the amino acid residue that is changed is in a relatively unimportant part of the enzyme, for example a long way from the active site then the mutation may be selectively neutral and subject to genetic drift.
- In rare cases the mutation may result in an enzyme that is more efficient, or one that can catalyse a slightly different chemical reaction, in which case the mutation may cause an increase in fitness, and be favoured by natural selection.
# An example of an isozyme
An example of an isozyme is glucokinase, a variant of hexokinase which is not inhibited by glucose 6-phosphate. Its different regulatory features and lower affinity for glucose (compared to other hexokinases), allows it to serve different functions in cells of specific organs, such as control of insulin release by the beta cells of the pancreas, or initiation of glycogen synthesis by liver cells. Both of these processes must only occur when glucose is abundant, or problems occur.
# Distinguishing isozymes
Isozymes (and allozymes) are variants of the same enzyme. Unless they are identical in terms of their biochemical properties, for example their substrates and enzyme kinetics, they may be distinguished by a biochemical assay. However, such differences are usually subtle (particularly between allozymes which are often neutral variants). This subtlety is to be expected, because two enzymes that differ significantly in their function are unlikely to have been identified as isozymes.
Whilst isozymes may be almost identical in function, they may differ in other ways. In particular, amino acid substitutions that change the electric charge of the enzyme (such as replacing aspartic acid with glutamic acid) are simple to identify by gel electrophoresis, and this forms the basis for the use of isozymes as molecular markers. To identify isozymes, a crude protein extract is made by grinding animal or plant tissue with an extraction buffer, and the components of extract are separated according to their charge by gel electrophoresis. Historically, this has usually been done using gels made from potato starch, however, acrylamide gels provide better resolution, and cellulose acetate gels are now (as of 2005) the norm.
All the proteins from the tissue are present in the gel, so that individual enzymes must be identified using an assay that links their function to a staining reaction. For example, detection can be based on the localised precipitation of soluble indicator dyes such as tetrazolium salts which become insoluble when they are reduced by cofactors such as NAD or NADP, which generated in zones of enzyme activity. This assay method requires that the enzymes are still functional after separation (native gel electrophoresis), and provides the greatest challenge to using isozymes as a laboratory technique.
# Isozymes and allozymes as molecular markers
Population genetics is essentially a study of the causes and effects of genetic variation within and between populations, and in the past isozymes have been amongst the most widely used Molecular markers for this purpose. Although they have now been largely superseded by more informative DNA-based approaches (such as direct DNA sequencing, single nucleotide polymorphisms and microsatellites), they are still amongst the quickest and cheapest marker systems to develop, and remain (as of 2005) an excellent choice for projects that only need to identify low levels of genetic variation, e.g. quantifying mating systems. | Isozyme
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Isozymes (also known as isoenzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. These enzymes usually display different kinetic parameters (i.e. different KM values), or different regulatory properties.
The existence of isozymes permits the fine-tuning of metabolism to meet the particular needs of a given tissue or developmental stage (for example lactate dehydrogenase (LDH)).
In biochemistry, isozymes (or isoenzymes) are isoforms (closely related variants) of enzymes. In many cases, they are coded for by homologous genes that have diverged over time. Although, strictly speaking, allozymes represent enzymes from different alleles of the same gene, and isozymes represent enzymes from different genes whose products catalyse the same reaction, the two words are usually used interchangeably.
# Introduction
Isozymes were first described by R. L. Hunter and Clement Markert (1957) who defined them as different variants of the same enzyme having identical functions and present in the same individual. This definition encompasses (1) enzyme variants that are the product of different genes and thus represent different loci (described as isozymes) and (2) enzymes that are the product of different alleles of the same gene (described as allozymes).
Isozymes are usually the result of gene duplication, but can also arise from polyploidisation or nucleic acid hybridization. Over evolutionary time, if the function of the new variant remains identical to the original, then it is likely that one or the other will be lost as mutations accumulate, resulting in a pseudogene. However, if the mutations do not immediately prevent the enzyme from functioning, but instead modify either its function, or its pattern of gene expression, then the two variants may both be favoured by natural selection and become specialised to different functions. For example, they may be expressed at different stages of development or in different tissues.
Allozymes may result from point mutations or from insertion-deletion (indel) events that affect the DNA coding sequence of the gene. As with any other new mutation, there are three things that may happen to a new allozyme:
- It is most likely that the new allele will be non-functional — in which case it will probably result in low fitness and be removed from the population by natural selection.
- Alternatively, if the amino acid residue that is changed is in a relatively unimportant part of the enzyme, for example a long way from the active site then the mutation may be selectively neutral and subject to genetic drift.
- In rare cases the mutation may result in an enzyme that is more efficient, or one that can catalyse a slightly different chemical reaction, in which case the mutation may cause an increase in fitness, and be favoured by natural selection.
# An example of an isozyme
An example of an isozyme is glucokinase, a variant of hexokinase which is not inhibited by glucose 6-phosphate. Its different regulatory features and lower affinity for glucose (compared to other hexokinases), allows it to serve different functions in cells of specific organs, such as control of insulin release by the beta cells of the pancreas, or initiation of glycogen synthesis by liver cells. Both of these processes must only occur when glucose is abundant, or problems occur.
# Distinguishing isozymes
Isozymes (and allozymes) are variants of the same enzyme. Unless they are identical in terms of their biochemical properties, for example their substrates and enzyme kinetics, they may be distinguished by a biochemical assay. However, such differences are usually subtle (particularly between allozymes which are often neutral variants). This subtlety is to be expected, because two enzymes that differ significantly in their function are unlikely to have been identified as isozymes.
Whilst isozymes may be almost identical in function, they may differ in other ways. In particular, amino acid substitutions that change the electric charge of the enzyme (such as replacing aspartic acid with glutamic acid) are simple to identify by gel electrophoresis, and this forms the basis for the use of isozymes as molecular markers. To identify isozymes, a crude protein extract is made by grinding animal or plant tissue with an extraction buffer, and the components of extract are separated according to their charge by gel electrophoresis. Historically, this has usually been done using gels made from potato starch, however, acrylamide gels provide better resolution, and cellulose acetate gels are now (as of 2005) the norm.
All the proteins from the tissue are present in the gel, so that individual enzymes must be identified using an assay that links their function to a staining reaction. For example, detection can be based on the localised precipitation of soluble indicator dyes such as tetrazolium salts which become insoluble when they are reduced by cofactors such as NAD or NADP, which generated in zones of enzyme activity. This assay method requires that the enzymes are still functional after separation (native gel electrophoresis), and provides the greatest challenge to using isozymes as a laboratory technique.
# Isozymes and allozymes as molecular markers
Population genetics is essentially a study of the causes and effects of genetic variation within and between populations, and in the past isozymes have been amongst the most widely used Molecular markers for this purpose. Although they have now been largely superseded by more informative DNA-based approaches (such as direct DNA sequencing, single nucleotide polymorphisms and microsatellites), they are still amongst the quickest and cheapest marker systems to develop, and remain (as of 2005) an excellent choice for projects that only need to identify low levels of genetic variation, e.g. quantifying mating systems. | https://www.wikidoc.org/index.php/Isoenzyme | |
c7b2012e888ec2d3a20f29f38afe79790d7ae7d1 | wikidoc | Isotope | Isotope
# Overview
Isotopes are any of the several different forms of an element each having different atomic mass (mass number). Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons. Therefore, isotopes have different mass numbers, which give the total number of nucleons—the number of protons plus neutrons.
A nuclide is any particular atomic nucleus with a specific atomic number Z and mass number A; it is equivalently an atomic nucleus with a specific number of protons and neutrons. Collectively, all the isotopes of all the elements form the set of nuclides. The distinction between the terms isotope and nuclide has somewhat blurred, and they are often used interchangeably. Isotope is best used when referring to several different nuclides of the same element; nuclide is more generic and is used when referencing only one nucleus or several nuclei of different elements. For example, it is more correct to say that an element such as fluorine consists of one stable nuclide rather than that it has one stable isotope.
In IUPAC nomenclature, isotopes and nuclides are specified by the name of the particular element, implicitly giving the atomic number, followed by a hyphen and the mass number (e.g. helium-3, carbon-12, carbon-13, iodine-131 and uranium-238). In symbolic form, the number of nucleons is denoted as a superscripted prefix to the chemical symbol (e.g. 3He, 12C, 13C, 131I and 238U).
The term isotope was coined in 1913 by Margaret Todd, a Scottish doctor, during a conversation with Frederick Soddy (to whom she was distantly related by marriage). Soddy, a chemist at Glasgow University, explained that it appeared from his investigations as if several elements occupied each position in the periodic table. Hence Todd suggested the Greek for "at the same place" as a suitable name. Soddy adopted the term and went on to win the Nobel Prize for Chemistry in 1921 for his work on radioactive substances.
In 1913, as part of his exploration into the composition of canal rays, JJ Thomson channeled a stream of ionized neon through a magnetic and an electric field and measured its deflection by placing a photographic plate in its path. Thomson observed two patches of light on the photographic plate (see image on right), which suggested two different parabolas of deflection. Thomson concluded that some of the atoms in the gas were of higher mass than the rest.
# Variation in properties between isotopes
A neutral atom has the same number of electrons as protons. Thus, different isotopes of a given element all have the same number of protons and electrons and the same electronic structure, and because the chemical behavior of an atom is largely determined by its electronic structure, different isotopes exhibit nearly identical chemical behavior. The main exception to this is the kinetic isotope effect: due to their larger masses, heavier isotopes tend to react somewhat more slowly than lighter isotopes of the same element. This is most pronounced for protium (1H) vis-à-vis deuterium (2H), because deuterium has twice the mass of protium. For heavier elements the relative mass difference between isotopes is much less, and the mass effect is usually negligible.
Similarly, two molecules which differ only in the isotopic nature of their atoms (isotopologues) will have identical electronic structure and therefore almost indistinguishable physical and chemical properties (again with deuterium providing the primary exception to this rule). The vibrational modes of a molecule are determined by its shape and by the masses of its constituent atoms. Consequently, isotopologues will have different sets of vibrational modes. Since vibrational modes allow a molecule to absorb photons of corresponding energies, isotopologues have different optical properties in the infrared range.
Although isotopes exhibit nearly identical electronic and chemical behavior, their nuclear behavior varies dramatically. Atomic nuclei consist of protons and neutrons bound together by the strong nuclear force. Because protons are positively charged, they repel each other. Neutrons, which are electrically neutral, allow some separation between the positively charged protons, reducing the electrostatic repulsion. Neutrons also stabilize the nucleus because at short ranges they attract each other and protons equally by the strong nuclear force, and this also offsets the electrical repulsion between protons. For this reason, one or more neutrons are necessary for two or more protons to be bound into a nucleus. As the number of protons increases, additional neutrons are needed to form a stable nucleus; for example, although the neutron to proton ratio of 3He is 1:2, the neutron/proton ratio of 238U is greater than 3:2. If too many or too few neutrons are present, the nucleus is unstable and subject to nuclear decay. As a rule there is for each mass number only one stable stable isotope, having the right proportion of protons and neutrons, while the others decay by beta decay or double-beta decay.
# Occurrence in nature
Elements are composed of one or more naturally occurring isotopes, which are normally stable. Some elements have unstable (radioactive) isotopes, either because their decay is so slow that a fraction still remains since they were created (examples: uranium, potassium), or because they are continually created through cosmic radiation (tritium, carbon-14) or by decay from an isotope in the first category (radium, radon).
The tabulated atomic masses of elements are averages that account for the presence of multiple isotopes with different masses. A good example is chlorine, having the composition 35Cl, 75.8%, and 37Cl, 24.2%, giving an atomic mass of 35.5. Values like this confounded scientists before the discovery of isotopes, as most light element atomic masses are close to integer multiples of hydrogen.
According to generally accepted cosmology only the isotopes of hydrogen and helium, and traces of some isotopes of lithium, beryllium and boron were created at the big bang, while all others were synthesized in stars and supernovae. (See nucleosynthesis.) Their respective abundances on Earth result from the quantities formed by these processes, their spread through the galaxy, and their rates of decay. After the initial coalescence of the solar system, isotopes were redistributed according to mass, and the isotopic composition of elements varies slightly from planet to planet. This sometimes makes it possible to trace the origin of meteorites.
# Molecular mass of isotopes
The molecular mass (Mr) of an element is determined by its nucleons. For example, Carbon-12 (12C) has 6 Protons and 6 Neutrons. When a sample contains two isotopes the equation below is applied where Mr(1) and Mr(2) are the molecular masses of each individual isotope, and % abundance is the percentage abundance of that isotope in the sample.
# Applications of isotopes
Several applications exist that capitalize on properties of the various isotopes of a given element.
## Use of chemical and biological properties
- Isotope analysis is the determination of isotopic signature, the relative abundances of isotopes of a given element in a particular sample. For biogenic substances in particular, significant variations of isotopes of C, N and O can occur. Analysis of such variations has a wide range of applications, such as the detection of adulteration of food products. The identification of certain meteorites as having originated on Mars is based in part upon the isotopic signature of trace gases contained in them.
- Another common application is isotopic labeling, the use of unusual isotopes as tracers or markers in chemical reactions. Normally, atoms of a given element are indistinguishable from each other. However, by using isotopes of different masses, they can be distinguished by mass spectrometry or infrared spectroscopy (see "Properties"). For example, in 'stable isotope labeling with amino acids in cell culture (SILAC)' stable isotopes are used to quantify proteins. If radioactive isotopes are used, they can be detected by the radiation they emit (this is called radioisotopic labeling).
- A technique similar to radioisotopic labelling is radiometric dating: using the known half-life of an unstable element, one can calculate the amount of time that has elapsed since a known level of isotope existed. The most widely known example is radiocarbon dating used to determine the age of carbonaceous materials.
- Isotopic substitution can be used to determine the mechanism of a reaction via the kinetic isotope effect.
## Use of nuclear properties
- Several forms of spectroscopy rely on the unique nuclear properties of specific isotopes. For example, nuclear magnetic resonance (NMR) spectroscopy can be used only for isotopes with a nonzero nuclear spin. The most common isotopes used with NMR spectroscopy are 1H, 2D,15N, 13C, and 31P.
- Mössbauer spectroscopy also relies on the nuclear transitions of specific isotopes, such as 57Fe.
- Radionuclides also have important uses. Nuclear power and nuclear weapons development require relatively large quantities of specific isotopes. The process of isotope separation represents a significant technological challenge, but more so with heavy elements such as uranium or plutonium, than with lighter elements such as hydrogen, lithium, carbon, nitrogen, and oxygen. The lighter elements are commonly separated by gas diffusion of their compounds such as CO and NO. Uranium isotopes have been separated in bulk by gas diffusion, gas centrifugation, laser ionization separation, and (in the Manhattan Project) by a type of production mass spectroscopy. | Isotope
# Overview
Isotopes are any of the several different forms of an element each having different atomic mass (mass number). Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons. Therefore, isotopes have different mass numbers, which give the total number of nucleons—the number of protons plus neutrons.
A nuclide is any particular atomic nucleus with a specific atomic number Z and mass number A; it is equivalently an atomic nucleus with a specific number of protons and neutrons. Collectively, all the isotopes of all the elements form the set of nuclides. The distinction between the terms isotope and nuclide has somewhat blurred, and they are often used interchangeably. Isotope is best used when referring to several different nuclides of the same element; nuclide is more generic and is used when referencing only one nucleus or several nuclei of different elements. For example, it is more correct to say that an element such as fluorine consists of one stable nuclide rather than that it has one stable isotope.
In IUPAC nomenclature, isotopes and nuclides are specified by the name of the particular element, implicitly giving the atomic number, followed by a hyphen and the mass number (e.g. helium-3, carbon-12, carbon-13, iodine-131 and uranium-238). In symbolic form, the number of nucleons is denoted as a superscripted prefix to the chemical symbol (e.g. 3He, 12C, 13C, 131I and 238U).
The term isotope was coined in 1913 by Margaret Todd, a Scottish doctor, during a conversation with Frederick Soddy (to whom she was distantly related by marriage).[1] Soddy, a chemist at Glasgow University, explained that it appeared from his investigations as if several elements occupied each position in the periodic table. Hence Todd suggested the Greek for "at the same place" as a suitable name. Soddy adopted the term and went on to win the Nobel Prize for Chemistry in 1921 for his work on radioactive substances.
In 1913, as part of his exploration into the composition of canal rays, JJ Thomson channeled a stream of ionized neon through a magnetic and an electric field and measured its deflection by placing a photographic plate in its path. Thomson observed two patches of light on the photographic plate (see image on right), which suggested two different parabolas of deflection. Thomson concluded that some of the atoms in the gas were of higher mass than the rest.
# Variation in properties between isotopes
A neutral atom has the same number of electrons as protons. Thus, different isotopes of a given element all have the same number of protons and electrons and the same electronic structure, and because the chemical behavior of an atom is largely determined by its electronic structure, different isotopes exhibit nearly identical chemical behavior. The main exception to this is the kinetic isotope effect: due to their larger masses, heavier isotopes tend to react somewhat more slowly than lighter isotopes of the same element. This is most pronounced for protium (1H) vis-à-vis deuterium (2H), because deuterium has twice the mass of protium. For heavier elements the relative mass difference between isotopes is much less, and the mass effect is usually negligible.
Similarly, two molecules which differ only in the isotopic nature of their atoms (isotopologues) will have identical electronic structure and therefore almost indistinguishable physical and chemical properties (again with deuterium providing the primary exception to this rule). The vibrational modes of a molecule are determined by its shape and by the masses of its constituent atoms. Consequently, isotopologues will have different sets of vibrational modes. Since vibrational modes allow a molecule to absorb photons of corresponding energies, isotopologues have different optical properties in the infrared range.
Although isotopes exhibit nearly identical electronic and chemical behavior, their nuclear behavior varies dramatically. Atomic nuclei consist of protons and neutrons bound together by the strong nuclear force. Because protons are positively charged, they repel each other. Neutrons, which are electrically neutral, allow some separation between the positively charged protons, reducing the electrostatic repulsion. Neutrons also stabilize the nucleus because at short ranges they attract each other and protons equally by the strong nuclear force, and this also offsets the electrical repulsion between protons. For this reason, one or more neutrons are necessary for two or more protons to be bound into a nucleus. As the number of protons increases, additional neutrons are needed to form a stable nucleus; for example, although the neutron to proton ratio of 3He is 1:2, the neutron/proton ratio of 238U is greater than 3:2. If too many or too few neutrons are present, the nucleus is unstable and subject to nuclear decay. As a rule there is for each mass number only one stable stable isotope, having the right proportion of protons and neutrons, while the others decay by beta decay or double-beta decay.
# Occurrence in nature
Elements are composed of one or more naturally occurring isotopes, which are normally stable. Some elements have unstable (radioactive) isotopes, either because their decay is so slow that a fraction still remains since they were created (examples: uranium, potassium), or because they are continually created through cosmic radiation (tritium, carbon-14) or by decay from an isotope in the first category (radium, radon).
The tabulated atomic masses of elements are averages that account for the presence of multiple isotopes with different masses. A good example is chlorine, having the composition 35Cl, 75.8%, and 37Cl, 24.2%, giving an atomic mass of 35.5. Values like this confounded scientists before the discovery of isotopes, as most light element atomic masses are close to integer multiples of hydrogen.
According to generally accepted cosmology only the isotopes of hydrogen and helium, and traces of some isotopes of lithium, beryllium and boron were created at the big bang, while all others were synthesized in stars and supernovae. (See nucleosynthesis.) Their respective abundances on Earth result from the quantities formed by these processes, their spread through the galaxy, and their rates of decay. After the initial coalescence of the solar system, isotopes were redistributed according to mass, and the isotopic composition of elements varies slightly from planet to planet. This sometimes makes it possible to trace the origin of meteorites.
# Molecular mass of isotopes
The molecular mass (Mr) of an element is determined by its nucleons. For example, Carbon-12 (12C) has 6 Protons and 6 Neutrons. When a sample contains two isotopes the equation below is applied where Mr(1) and Mr(2) are the molecular masses of each individual isotope, and % abundance is the percentage abundance of that isotope in the sample.
# Applications of isotopes
Several applications exist that capitalize on properties of the various isotopes of a given element.
## Use of chemical and biological properties
- Isotope analysis is the determination of isotopic signature, the relative abundances of isotopes of a given element in a particular sample. For biogenic substances in particular, significant variations of isotopes of C, N and O can occur. Analysis of such variations has a wide range of applications, such as the detection of adulteration of food products.[2] The identification of certain meteorites as having originated on Mars is based in part upon the isotopic signature of trace gases contained in them.[3]
- Another common application is isotopic labeling, the use of unusual isotopes as tracers or markers in chemical reactions. Normally, atoms of a given element are indistinguishable from each other. However, by using isotopes of different masses, they can be distinguished by mass spectrometry or infrared spectroscopy (see "Properties"). For example, in 'stable isotope labeling with amino acids in cell culture (SILAC)' stable isotopes are used to quantify proteins. If radioactive isotopes are used, they can be detected by the radiation they emit (this is called radioisotopic labeling).
- A technique similar to radioisotopic labelling is radiometric dating: using the known half-life of an unstable element, one can calculate the amount of time that has elapsed since a known level of isotope existed. The most widely known example is radiocarbon dating used to determine the age of carbonaceous materials.
- Isotopic substitution can be used to determine the mechanism of a reaction via the kinetic isotope effect.
## Use of nuclear properties
- Several forms of spectroscopy rely on the unique nuclear properties of specific isotopes. For example, nuclear magnetic resonance (NMR) spectroscopy can be used only for isotopes with a nonzero nuclear spin. The most common isotopes used with NMR spectroscopy are 1H, 2D,15N, 13C, and 31P.
- Mössbauer spectroscopy also relies on the nuclear transitions of specific isotopes, such as 57Fe.
- Radionuclides also have important uses. Nuclear power and nuclear weapons development require relatively large quantities of specific isotopes. The process of isotope separation represents a significant technological challenge, but more so with heavy elements such as uranium or plutonium, than with lighter elements such as hydrogen, lithium, carbon, nitrogen, and oxygen. The lighter elements are commonly separated by gas diffusion of their compounds such as CO and NO. Uranium isotopes have been separated in bulk by gas diffusion, gas centrifugation, laser ionization separation, and (in the Manhattan Project) by a type of production mass spectroscopy. | https://www.wikidoc.org/index.php/Isotope | |
a5ad7b995cad7c9d26222f542f7b4c801b76b9ef | wikidoc | Isthmus | Isthmus
An isthmus (Template:IPAEng, Template:Lang-el, plural isthmuses or isthmi) is a narrow strip of land that is bordered on two sides by water and connects two larger land masses. It is the inverse of a strait (which lies between two land masses and connects two larger bodies of water).
Isthmi are naturally good places to build canals. The Panama Canal, for instance, which connects the Atlantic and Pacific Oceans, drastically reduces the naval travel time between the east and west coasts of America.
# List of isthmuses
- Auckland isthmus, which connects the North Auckland Peninsula|Northland Peninsula to the rest of New Zealand's North Island.
- Isthmus of Avalon, which connects the populous Avalon Peninsula to the rest of Newfoundland.
- Isthmus of Corinth, which connects the Peloponnese peninsula to the rest of Greece.
- Isthmus of Gibraltar, which joins Gibraltar to mainland Spain.
- Karelian Isthmus between Gulf of Finland and Lake Ladoga.
- Isthmus of Kra, which joins the Malay Peninsula with mainland Asia.
- Isthmus of Kushimoto in Japan - connects Honshū with Cape Shiono-Misaki.
- La Coupée isthmus in Sark.
- Madison Isthmus, between Lake Mendota and Lake Monona in Madison, Wisconsin.
- Mavis Grind isthmus in Shetland, UK.
- Isthmus of Médanos - licks Venezuela to Médanos.
- Neck in Bruny Island, Tasmania - connects North and South Bruny.
- Ofqui Isthmus, Aysen Region, Chile.
- Isthmus of Panama - arguably the most famous isthmus, connects North America and South America.
- Isthmus of Perekop between Crimea and Ukraine proper.
- Isthmus of Potidea, connecting the Kassandra peninsula with the mainland of Greece.
- Quezon Province, in Luzon, Philippines - connecting Bicol peninsula with mainland Luzon.
- Adam's Bridge, between India and Sri Lanka (a former Isthmus).
- Isthmus of Suez - the isthmus between North Africa and Southwest Asia, in Egypt where the Suez Canal is located.
- Isthmus of Summerside, connecting the Western section of Prince Edward Island, Canada with the remainder of the island.
- Isthmus of Tehuantepec - connects Yucatan and Central America with the rest of Mexico.
- Isthumus of Nahant connecting Nahant, Massachusetts to Massachusetts. | Isthmus
An isthmus (Template:IPAEng, Template:Lang-el, plural isthmuses or isthmi) is a narrow strip of land that is bordered on two sides by water and connects two larger land masses. It is the inverse of a strait (which lies between two land masses and connects two larger bodies of water).
Isthmi are naturally good places to build canals. The Panama Canal, for instance, which connects the Atlantic and Pacific Oceans, drastically reduces the naval travel time between the east and west coasts of America.
# List of isthmuses
- Auckland isthmus, which connects the North Auckland Peninsula|Northland Peninsula to the rest of New Zealand's North Island.
- Isthmus of Avalon, which connects the populous Avalon Peninsula to the rest of Newfoundland.
- Isthmus of Corinth, which connects the Peloponnese peninsula to the rest of Greece.
- Isthmus of Gibraltar, which joins Gibraltar to mainland Spain.
- Karelian Isthmus between Gulf of Finland and Lake Ladoga.
- Isthmus of Kra, which joins the Malay Peninsula with mainland Asia.
- Isthmus of Kushimoto in Japan - connects Honshū with Cape Shiono-Misaki.
- La Coupée isthmus in Sark.
- Madison Isthmus, between Lake Mendota and Lake Monona in Madison, Wisconsin.
- Mavis Grind isthmus in Shetland, UK.
- Isthmus of Médanos - licks Venezuela to Médanos.
- Neck in Bruny Island, Tasmania - connects North and South Bruny.
- Ofqui Isthmus, Aysen Region, Chile.
- Isthmus of Panama - arguably the most famous isthmus, connects North America and South America.
- Isthmus of Perekop between Crimea and Ukraine proper.
- Isthmus of Potidea, connecting the Kassandra peninsula with the mainland of Greece.
- Quezon Province, in Luzon, Philippines - connecting Bicol peninsula with mainland Luzon.
- Adam's Bridge, between India and Sri Lanka (a former Isthmus).
- Isthmus of Suez - the isthmus between North Africa and Southwest Asia, in Egypt where the Suez Canal is located.
- Isthmus of Summerside, connecting the Western section of Prince Edward Island, Canada with the remainder of the island.
- Isthmus of Tehuantepec - connects Yucatan and Central America with the rest of Mexico.
- Isthumus of Nahant connecting Nahant, Massachusetts to Massachusetts. | https://www.wikidoc.org/index.php/Isthmus | |
6393bec5fe14183575addbfeb9e7f03d5de8f837 | wikidoc | Isuprel | Isuprel
Isoproterenol hydrochloride or isoprenaline (Medihaler-Iso®) is a sympathomimetic beta adrenergic receptor agonist medication.
It is structurally similar to epinephrine but acts for the most part on beta receptors.
# Uses
It is used as an inhaled aerosol to treat asthma. Although it activates all beta adrenergic receptors, it works in a similar fashion to the more selective beta2-adrenergic receptor agonists e.g. salbutamol, by relaxing the airways to increase airflow.
It is also supplied in ampules under the brand name Isuprel® for injection and in sublingual pill form for treatment of asthma, chronic bronchitis and emphysema.
Used with caution, it can also be used to treat torsades de pointes, in conjunction with overdrive pacing and magnesium.
# Pharmacology
Isoproterenol is a β1- and β2-adrenoceptor agonist which was commonly used to treat asthma before the more widespread use of salbutamol, which has more selective effects on the airways. Its route of administration is either intravenous, oral, intranasal, subcutaneous, or intramuscular, depending on use. The plasma half-life for isoproterenol is approximately two hours.
Isoproterenol's effects on the cardiovascular system relate to its actions on cardiac β1 receptors and β2 receptors on skeletal muscle arterioles. Isoproterenol has positive inotropic and chronotropic effects on the heart. In skeletal muscle arterioles it produces vasodilatation. Its inotropic and chronotropic effects elevate systolic blood pressure, while its vasodilatory effects tend to lower diastolic blood pressure.
The adverse effects of isoproterenol are also related to the drug's cardiovascular effects. Isoproterenol can produce an elevated heart rate (tachycardia), which predisposes patients to cardiac dysrhythmias.
# Warnings and Contraindications
Isoproterenol should not be administered to patients with myocardial ischaemia.
de:Isoprenalin
it:Isoprotenerolo
sk:Izoprenalín | Isuprel
Isoproterenol hydrochloride or isoprenaline (Medihaler-Iso®) is a sympathomimetic beta adrenergic receptor agonist medication.
It is structurally similar to epinephrine but acts for the most part on beta receptors.
# Uses
It is used as an inhaled aerosol to treat asthma. Although it activates all beta adrenergic receptors, it works in a similar fashion to the more selective beta2-adrenergic receptor agonists e.g. salbutamol, by relaxing the airways to increase airflow.
It is also supplied in ampules under the brand name Isuprel® for injection and in sublingual pill form for treatment of asthma, chronic bronchitis and emphysema.
Used with caution, it can also be used to treat torsades de pointes, in conjunction with overdrive pacing and magnesium.
# Pharmacology
Isoproterenol is a β1- and β2-adrenoceptor agonist which was commonly used to treat asthma before the more widespread use of salbutamol, which has more selective effects on the airways. Its route of administration is either intravenous, oral, intranasal, subcutaneous, or intramuscular, depending on use. The plasma half-life for isoproterenol is approximately two hours.
Isoproterenol's effects on the cardiovascular system relate to its actions on cardiac β1 receptors and β2 receptors on skeletal muscle arterioles. Isoproterenol has positive inotropic and chronotropic effects on the heart. In skeletal muscle arterioles it produces vasodilatation. Its inotropic and chronotropic effects elevate systolic blood pressure, while its vasodilatory effects tend to lower diastolic blood pressure.
The adverse effects of isoproterenol are also related to the drug's cardiovascular effects. Isoproterenol can produce an elevated heart rate (tachycardia), which predisposes patients to cardiac dysrhythmias.
# Warnings and Contraindications
Isoproterenol should not be administered to patients with myocardial ischaemia.
Template:Adrenergic and dopaminergic agents
Template:Pharma-stub
de:Isoprenalin
it:Isoprotenerolo
sk:Izoprenalín
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/Isuprel | |
d4832252583ee45194838c8aeccf0c0fae2bd490 | wikidoc | JARID1A | JARID1A
Jumonji, AT rich interactive domain 1A, also known as JARID1A, is a human gene.
The protein encoded by this gene is a ubiquitously expressed nuclear protein. It binds directly, with several other proteins, to retinoblastoma protein which regulates cell proliferation. It was formally known as Retinoblastoma Binding Protein 2 (RBP2). This protein also interacts with rhombotin-2 which functions distinctly in erythropoiesis and in T-cell leukemogenesis. Rhombotin-2 is thought to either directly affect the activity of the encoded protein or may indirectly modulate the functions of the retinoblastoma protein by binding to this protein. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene.
This protein was found to be an H3K4 histone demethylase that binds to c-Myc. It was recently renamed to Lysine Demethylase 5A (KDM5A). | JARID1A
Jumonji, AT rich interactive domain 1A, also known as JARID1A, is a human gene.[1]
The protein encoded by this gene is a ubiquitously expressed nuclear protein. It binds directly, with several other proteins, to retinoblastoma protein which regulates cell proliferation. It was formally known as Retinoblastoma Binding Protein 2 (RBP2). This protein also interacts with rhombotin-2 which functions distinctly in erythropoiesis and in T-cell leukemogenesis. Rhombotin-2 is thought to either directly affect the activity of the encoded protein or may indirectly modulate the functions of the retinoblastoma protein by binding to this protein. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene.[1]
This protein was found to be an H3K4 histone demethylase that binds to c-Myc. [2] It was recently renamed to Lysine Demethylase 5A (KDM5A). | https://www.wikidoc.org/index.php/JARID1A | |
082594da610215ddf08885054890c76a9c2b2370 | wikidoc | JARID1B | JARID1B
Lysine-specific demethylase 5B also known as histone demethylase JARID1B is a demethylase enzyme that in humans is encoded by the KDM5B gene. JARID1B belongs to the alpha-ketoglutarate-dependent hydroxylase superfamily.
# Function
Jarid1B (also known as KDM5B or PLU1) is in the family of JHDM genes. These are responsible for demethylation of tri- and di-methylated lysines in the 4 position of histone 3 (H3K4me3 and H3K4me2). Jarid1B is a multidomain enzyme that is part of the subfamily KDM5. The whole Jarid1 family is a protein family that possesses H3K4 histone demethylase activity.
Jarid1B has been implicated in the development of prostate, breast, and skin cancer and also has been associated with melanoma maintenance. Knockout mice (Jarid1b−/−) produced are viable in neonatal life. These mice do exhibit the phenotype of premature mortality, decreased fertility in female mice, reduction in body weight and impairment in mammary gland development. It also acted to decrease serum estrogen levels and caused reduced mammary epithelial cell proliferation in the early stages of puberty. These Jarid1b−/− mice seem to be greatly affected in many regulators of the development of mammy development such as FOXA1 and estrogen receptor α. However, others have shown that a Jarid1B knockout embryos usually have neonatal lethality due to the failure of their respiratory system. Knockout embryos have also been seen to have several different neural defects including: disorganized cranial nerves, increased incidences of exencephaly, and defects in eye development.
# Interactions
JARID1B has been shown to interact with FOXG1 and PAX9. | JARID1B
Lysine-specific demethylase 5B also known as histone demethylase JARID1B is a demethylase enzyme that in humans is encoded by the KDM5B gene.[1][2][3] JARID1B belongs to the alpha-ketoglutarate-dependent hydroxylase superfamily.
# Function
Jarid1B (also known as KDM5B or PLU1) is in the family of JHDM genes. These are responsible for demethylation of tri- and di-methylated lysines in the 4 position of histone 3 (H3K4me3 and H3K4me2). Jarid1B is a multidomain enzyme that is part of the subfamily KDM5. The whole Jarid1 family is a protein family that possesses H3K4 histone demethylase activity.[4]
Jarid1B has been implicated in the development of prostate, breast, and skin cancer and also has been associated with melanoma maintenance. Knockout mice (Jarid1b−/−) produced are viable in neonatal life. These mice do exhibit the phenotype of premature mortality, decreased fertility in female mice, reduction in body weight and impairment in mammary gland development. It also acted to decrease serum estrogen levels and caused reduced mammary epithelial cell proliferation in the early stages of puberty. These Jarid1b−/− mice seem to be greatly affected in many regulators of the development of mammy development such as FOXA1 and estrogen receptor α.[5] However, others have shown that a Jarid1B knockout embryos usually have neonatal lethality due to the failure of their respiratory system. Knockout embryos have also been seen to have several different neural defects including: disorganized cranial nerves, increased incidences of exencephaly, and defects in eye development.[6]
# Interactions
JARID1B has been shown to interact with FOXG1[7] and PAX9.[7] | https://www.wikidoc.org/index.php/JARID1B | |
27d71c6786e7d95b494ec4728452ac43f4d5b2c9 | wikidoc | JWH-051 | JWH-051
JWH-051 is an analgesic drug which is a cannabinoid agonist. Its chemical structure is closely related to that of the potent cannabinoid agonist HU-210, with the only difference being the removal of the hydroxyl group at position 1 of the aromatic ring.
JWH-051 retains high affinity for the CB1 receptor, but is a much stronger agonist for CB2, with a Ki value of 0.03nM at CB2 vs 1.20nM at CB1. It was one of the first CB2-selective ligands developed, although its selectivity for CB2 is modest compared to newer compounds such as HU-308.
It has similar effects to other cannabinoid agonists such as sedation and analgesia, but with a relatively strong antiinflammatory effect due to its strong activity at CB2. | JWH-051
JWH-051 is an analgesic drug which is a cannabinoid agonist. Its chemical structure is closely related to that of the potent cannabinoid agonist HU-210, with the only difference being the removal of the hydroxyl group at position 1 of the aromatic ring.
JWH-051 retains high affinity for the CB1 receptor, but is a much stronger agonist for CB2, with a Ki value of 0.03nM at CB2 vs 1.20nM at CB1.[1] It was one of the first CB2-selective ligands developed, although its selectivity for CB2 is modest compared to newer compounds such as HU-308.
It has similar effects to other cannabinoid agonists such as sedation and analgesia, but with a relatively strong antiinflammatory effect due to its strong activity at CB2.[2][3][4]
Template:Pharm-stub | https://www.wikidoc.org/index.php/JWH-051 | |
7aafc1f773faa9335ab0b740b3c54b80e794a038 | wikidoc | J chain | J chain
A J chain is a protein component of the antibodies IgM and IgA. It is a 137 residue polypeptide, encoded by the IGJ gene.
# Structure
The J Chain's molecular weight is approximately 15 kDa. It exhibits a standard immunoglobulin folding structure of two β-pleated sheets of four ribbons folded against one another. It has 8 cystine residues. Two of these residues link the α chains of IgA or the μ chains of IgM via disulfide bridges, effectively serving as the "glue" between two Fc regions of the antibody.
The J-chain shows a large degree of homology between avian and human species, suggesting that it serves an important function.
# Function
The J Chain is required for IgM or IgA to be secreted into mucosa. As part of a polymeric immunoglobulin (pIg), the J-chain is essential for binding of pIg to the pIgR, which forms the secretory component upon excretion of the secretory pIg by epithelial cells. This binding facilitates transport of the J-chain positive pIg molecules from the basal to the apical sides of epithelial cells.
Because IgM and IgA are the only two types of antibody that polymerize, initial hypotheses stated that J chain was required for polymerization. However, it was subsequently found that IgM is able to polymerize in the absence of J chain as both a pentamer and a hexamer, however, both of these exist to lesser numbers in organisms lacking J chains. In such cases, there are also fewer IgA dimers.
The J-chain also plays a role in the activation of complement. J-chain negative IgM hexamers are 15-20 times more effective at activating complement than J-chain positive IgM pentamers. A consequence of this lack of complement activation is it allows J-chain positive pIgM to bind antigens without causing excessive damage to epithelial membranes through complement activation. | J chain
A J chain is a protein component of the antibodies IgM and IgA.[1] It is a 137 residue polypeptide,[2] encoded by the IGJ gene.[3][4][5]
# Structure
The J Chain's molecular weight is approximately 15 kDa. It exhibits a standard immunoglobulin folding structure of two β-pleated sheets of four ribbons folded against one another. It has 8 cystine residues. Two of these residues link the α chains of IgA or the μ chains of IgM via disulfide bridges, effectively serving as the "glue" between two Fc regions of the antibody.[6]
The J-chain shows a large degree of homology between avian and human species, suggesting that it serves an important function.[6]
# Function
The J Chain is required for IgM or IgA to be secreted into mucosa.[2] As part of a polymeric immunoglobulin (pIg), the J-chain is essential for binding of pIg to the pIgR, which forms the secretory component upon excretion of the secretory pIg by epithelial cells.[7] This binding facilitates transport of the J-chain positive pIg molecules from the basal to the apical sides of epithelial cells.
Because IgM and IgA are the only two types of antibody that polymerize, initial hypotheses stated that J chain was required for polymerization. However, it was subsequently found that IgM is able to polymerize in the absence of J chain as both a pentamer and a hexamer, however, both of these exist to lesser numbers in organisms lacking J chains. In such cases, there are also fewer IgA dimers.[2]
The J-chain also plays a role in the activation of complement. J-chain negative IgM hexamers are 15-20 times more effective at activating complement than J-chain positive IgM pentamers.[7] A consequence of this lack of complement activation is it allows J-chain positive pIgM to bind antigens without causing excessive damage to epithelial membranes through complement activation. | https://www.wikidoc.org/index.php/J_chain | |
11ae0732eff71a2ac5a25a8663fae5a079c6fa97 | wikidoc | Jacuzzi | Jacuzzi
Jacuzzi is a company producing whirlpool bathtubs and hot tubs. Its first product was a bath with massaging jets. The trademarked Jacuzzi name is also commonly used to refer to any bath with water jets, and can thus be considered a genericized trademark. Sometimes spas and hot tubs are also mistakenly referred to as Jacuzzis. The company advertises that "they are Jacuzzi, and everyone else's are just hot tubs." Their current slogan is "Jacuzzi: The Home Spa Experience."
# History
Around 1900, seven brothers named Jacuzzi emigrated from Italy to the United States. They eventually settled on the West Coast in Berkeley, California and became machinists. One of them, Rachele, began making aircraft propellers, inspired by an airshow he saw at the 1915 Panama Pacific Exposition in nearby San Francisco. He and his brothers created an aircraft manufacturing company in Berkeley called "Jacuzzi Bros.," which remained in business until 1976, although their product line changed over the years.
In 1925, as a result of a crash of one of their planes in 1921 en route between Yosemite and San Francisco, which killed brother Giocondo, Jacuzzi Bros. stopped making aircraft. Rachele turned the company's know-how in making hydraulic aircraft pumps to the manufacture of a new kind of deep well agricultural pump.
In 1948, brother Candido used the company's expertise in pumps to develop a submersible bathtub pump for his son who had contracted rheumatoid arthritis in 1943, at the age of 15 months, leaving the boy crippled and distorted with pain. The boy received regular hydrotherapy treatments at local hospitals but Candido could not stand to see his son suffering between the therapeutic visits. He realized that the water pumps Jacuzzi Brothers was making for industrial use could be adapted to give his son soothing whirlpool treatments in the tub at home. Jacuzzi Bros. marketed this pump, model J-300, in 1955. The son, Kenneth Jacuzzi, eventually came to run the company. During this period, Jack Benny was hired as a spokesman for Jacuzzi.
In 1955, the firm decided to market the Jacuzzi whirlpool bath as a therapeutic aid, selling it in drugstores and bath supply shops. To generate a little publicity for the unknown product portable Jacuzzis were included in the gifts showered on contestants on TV's Queen for a Day. It was pitched as relief for the worn-down housewife but when Hollywood stars like Randolph Scott and Jayne Mansfield, who were decidedly not worn-down, began offering testimonials the Jacuzzi started to acquire its legendary allure.
In 1968 Candido Jacuzzi invented and brought to market the first self-contained, fully integrated whirlpool bath by incorporating jets into the sides of the tub. See patent #3297,025 filed Jan. 10th, 1967. A new industry and era of whirlpool bathing pleasure was born. The Jacuzzi became a symbol of the sybaritic lifestyle. Hundreds of thousands of Jacuzzi portables were installed, both indoors and outdoors, at recreation centers and private homes. No self-respecting hotel suite could be rented without a Jacuzzi and in many places a Jacuzzi is standard in new homes.
But the whirlpool bath was still mostly a sideline at Jacuzzi Brothers. By far the bulk of Jacuzzi revenues came from sales of water pumps, marine jets and swimming pool equipment.
The J-300 pump was portable and could be placed in any bath enclosure. The medical community immediately saw the benefit of this product for their hydro-therapeutic programs. Physical Therapists and Orthopedists would prescribe their use in clinics and in the home. Hollywood celebrities began making personal use of them, bringing further popularity.
# Today
Jacuzzi branded hot tubs, baths, showers, toilets, sinks and accessories are commonly found in residential homes, hotels and aboard cruise ships and have become popular in high-end spas around the world. Jacuzzi products are distributed in about 60 countries.
The family history is the classic tale of European immigrants coming to the USA and living the American Dream. They arrived from Italy in the early 1900s. They started out by picking oranges and building small fixed-wing aircraft. They built a unique propeller known as the "Jacuzzi toothpick." They built the first enclosed cabin monoplane, which was used by the U.S. Postal Service to carry passengers from the San Francisco Bay area to Yosemite National Park.
Because of their knowledge and design experience in aircraft pumps, they turned their attention to the need of the agricultural community for groundwater. In 1925, the Jacuzzi brothers revolutionized the pump industry by designing the most efficient pump of the era. They received a Gold Medal at the California State Fair in 1930 for their new design.
In 1968, Roy Jacuzzi introduced the world to the "Roman Bathtub." This was the first integrated whirlpool bath. His patented jets, placed along the sides, produced a 50/50 air to water ratio providing an experience like none before. The same patented mixture ratio is still a signature feature of today's Jacuzzi jets. Suzanne Somers, then a model, was used in some of the first print advertisements published by Jacuzzi.
In the early 1970s, the company produced larger units with built-in heating and filtration systems. This was the beginning of the spa industry as we know it today. Friends and family were now invited to share the experience of a vacation in their own backyard.
Moving into the 1980s, the company's product line expanded with models that worked in multi-use configurations as hot tubs, whirlpool baths, or both. These models could be installed indoors or outdoors.
The Jacuzzi Spas International assembly plant is located in Chino, California. This plant was the first ISO 9001 certified hot tub production facility in the world. It has the capability of producing up to 300 spas per day for their domestic and export business needs. Their product line has many unique features such as patented jets, rainbow waterfalls, synthetic sun-resistant siding, stereos, ergonomic seating, triple-layered shells, full foam insulation, and a solid A.B.S. pan bottom.
Jacuzzi today is the world's most widely recognized name in jetted baths, spas, and hot tubs. | Jacuzzi
Template:Newsrelease
Template:Infobox Company
Jacuzzi is a company producing whirlpool bathtubs and hot tubs. Its first product was a bath with massaging jets. The trademarked Jacuzzi name is also commonly used to refer to any bath with water jets, and can thus be considered a genericized trademark. Sometimes spas and hot tubs are also mistakenly referred to as Jacuzzis. The company advertises that "they are Jacuzzi, and everyone else's are just hot tubs." Their current slogan is "Jacuzzi: The Home Spa Experience."
# History
Around 1900, seven brothers named Jacuzzi emigrated from Italy to the United States. They eventually settled on the West Coast in Berkeley, California and became machinists. One of them, Rachele, began making aircraft propellers, inspired by an airshow he saw at the 1915 Panama Pacific Exposition in nearby San Francisco. He and his brothers created an aircraft manufacturing company in Berkeley called "Jacuzzi Bros.," which remained in business until 1976, although their product line changed over the years.
In 1925, as a result of a crash of one of their planes in 1921 en route between Yosemite and San Francisco, which killed brother Giocondo, Jacuzzi Bros. stopped making aircraft. Rachele turned the company's know-how in making hydraulic aircraft pumps to the manufacture of a new kind of deep well agricultural pump.
In 1948, brother Candido used the company's expertise in pumps to develop a submersible bathtub pump for his son who had contracted rheumatoid arthritis in 1943, at the age of 15 months, leaving the boy crippled and distorted with pain. The boy received regular hydrotherapy treatments at local hospitals but Candido could not stand to see his son suffering between the therapeutic visits. He realized that the water pumps Jacuzzi Brothers was making for industrial use could be adapted to give his son soothing whirlpool treatments in the tub at home. Jacuzzi Bros. marketed this pump, model J-300, in 1955. The son, Kenneth Jacuzzi, eventually came to run the company. During this period, Jack Benny was hired as a spokesman for Jacuzzi.
In 1955, the firm decided to market the Jacuzzi whirlpool bath as a therapeutic aid, selling it in drugstores and bath supply shops. To generate a little publicity for the unknown product portable Jacuzzis were included in the gifts showered on contestants on TV's Queen for a Day. It was pitched as relief for the worn-down housewife but when Hollywood stars like Randolph Scott and Jayne Mansfield, who were decidedly not worn-down, began offering testimonials the Jacuzzi started to acquire its legendary allure.
In 1968 Candido Jacuzzi invented and brought to market the first self-contained, fully integrated whirlpool bath by incorporating jets into the sides of the tub. See patent #3297,025 filed Jan. 10th, 1967. A new industry and era of whirlpool bathing pleasure was born. The Jacuzzi became a symbol of the sybaritic lifestyle. Hundreds of thousands of Jacuzzi portables were installed, both indoors and outdoors, at recreation centers and private homes. No self-respecting hotel suite could be rented without a Jacuzzi and in many places a Jacuzzi is standard in new homes.
But the whirlpool bath was still mostly a sideline at Jacuzzi Brothers. By far the bulk of Jacuzzi revenues came from sales of water pumps, marine jets and swimming pool equipment.
The J-300 pump was portable and could be placed in any bath enclosure. The medical community immediately saw the benefit of this product for their hydro-therapeutic programs. Physical Therapists and Orthopedists would prescribe their use in clinics and in the home. Hollywood celebrities began making personal use of them, bringing further popularity.
# Today
Jacuzzi branded hot tubs, baths, showers, toilets, sinks and accessories are commonly found in residential homes, hotels and aboard cruise ships and have become popular in high-end spas around the world. Jacuzzi products are distributed in about 60 countries.
The family history is the classic tale of European immigrants coming to the USA and living the American Dream. They arrived from Italy in the early 1900s. They started out by picking oranges and building small fixed-wing aircraft. They built a unique propeller known as the "Jacuzzi toothpick." They built the first enclosed cabin monoplane, which was used by the U.S. Postal Service to carry passengers from the San Francisco Bay area to Yosemite National Park.
Because of their knowledge and design experience in aircraft pumps, they turned their attention to the need of the agricultural community for groundwater. In 1925, the Jacuzzi brothers revolutionized the pump industry by designing the most efficient pump of the era. They received a Gold Medal at the California State Fair in 1930 for their new design.
In 1968, Roy Jacuzzi introduced the world to the "Roman Bathtub." This was the first integrated whirlpool bath. His patented jets, placed along the sides, produced a 50/50 air to water ratio providing an experience like none before. The same patented mixture ratio is still a signature feature of today's Jacuzzi jets. Suzanne Somers, then a model, was used in some of the first print advertisements published by Jacuzzi.
In the early 1970s, the company produced larger units with built-in heating and filtration systems. This was the beginning of the spa industry as we know it today. Friends and family were now invited to share the experience of a vacation in their own backyard.
Moving into the 1980s, the company's product line expanded with models that worked in multi-use configurations as hot tubs, whirlpool baths, or both. These models could be installed indoors or outdoors.
The Jacuzzi Spas International assembly plant is located in Chino, California. This plant was the first ISO 9001 certified hot tub production facility in the world. It has the capability of producing up to 300 spas per day for their domestic and export business needs. Their product line has many unique features such as patented jets, rainbow waterfalls, synthetic sun-resistant siding, stereos, ergonomic seating, triple-layered shells, full foam insulation, and a solid A.B.S. pan bottom.
Jacuzzi today is the world's most widely recognized name in jetted baths, spas, and hot tubs. | https://www.wikidoc.org/index.php/Jacuzzi | |
53f5cf99116b7e761b60d48eb72f30782ac02a94 | wikidoc | Jejunum | Jejunum
# Overview
In anatomy of the digestive system, the jejunum is the central of the three divisions of the small intestine and lies between the duodenum and the ileum. The change from the duodenum to the jejunum is usually defined as the ligament of Treitz.
In adult humans, the small intestine is usually between 5.5-6m long, 2.5m of which is the jejunum.
The pH in the jejunum is usually between 7 and 8 (neutral or slightly alkaline).
The jejunum and the ileum are suspended by mesentery which gives the bowel great mobility within the abdomen. It also contains muscles to help move the food along.
# Internal structure
The inner surface of the jejunum, its mucous membrane, is covered in projections called villi, which increase the surface area of tissue available to absorb nutrients from the gut contents. The villi in the jejunum are much longer than in the duodenum or ileum.
The jejunum contains very few Brunner's glands (found in the duodenum) or Peyer's patches (found in the ileum). Instead, it has many large circular folds in its submucosa called plicae circulares which increase the surface area for nutrient absorption.
# Etymology
Jejunum is derived from the adjective jejune, which means "fasting" or "hungry" in Early Modern English.
It was so called because this portion of the intestine was found "empty" following death
# Additional images
- Duodenojejunal fossa.
- Transmission electron microscope (TEM) of Human Jejunum
- TEM of Mouse Jejunum x14000 | Jejunum
# Overview
Template:Infobox Anatomy
In anatomy of the digestive system, the jejunum is the central of the three divisions of the small intestine and lies between the duodenum and the ileum. The change from the duodenum to the jejunum is usually defined as the ligament of Treitz.
In adult humans, the small intestine is usually between 5.5-6m long, 2.5m of which is the jejunum.
The pH in the jejunum is usually between 7 and 8 (neutral or slightly alkaline).
The jejunum and the ileum are suspended by mesentery which gives the bowel great mobility within the abdomen. It also contains muscles to help move the food along.
# Internal structure
The inner surface of the jejunum, its mucous membrane, is covered in projections called villi, which increase the surface area of tissue available to absorb nutrients from the gut contents. The villi in the jejunum are much longer than in the duodenum or ileum.
The jejunum contains very few Brunner's glands (found in the duodenum) or Peyer's patches (found in the ileum). Instead, it has many large circular folds in its submucosa called plicae circulares which increase the surface area for nutrient absorption.
# Etymology
Jejunum is derived from the adjective jejune, which means "fasting" or "hungry" in Early Modern English.
It was so called because this portion of the intestine was found "empty" following death [Latin: jejunus, fasting; barren]
# Additional images
- Duodenojejunal fossa.
- Transmission electron microscope (TEM) of Human Jejunum
- TEM of Mouse Jejunum x14000 | https://www.wikidoc.org/index.php/Jejunum | |
d7a72f38e69ac1872467921bb714e7d3a9825f73 | wikidoc | Jet lag | Jet lag
# Overview
Jet lag, also jetlag or jet-lag, is a physiological condition which is a consequence of alterations to the circadian rhythm. Such disturbances may result from shift work, daylight saving time, altered day length, or, as the name implies, transmeridian travel (as on a jet plane). They are known as desynchronosis, dysrhythmia, dyschrony, jet lag, or jet syndrome. The condition is generally believed to be the result of disruption of the "light/dark" cycle that entrains the body's circadian rhythm. It can be exacerbated by environmental factors.
The condition of jet lag may last many days, and medical experts have deemed that a recovery rate of "one day per time zone" is a fair guideline. Good sleep hygiene promotes rapid recovery from jet lag: in fact sleep, relaxation, moderate exercise, and sensible diet seem to be the simplest recovery methods.
However, since the experience of jet lag varies among individuals, it is difficult to assess the efficacy of any single remedy. Age may also be a factor on the severity of jet lag, as younger people will suffer worse jet lag than older people would.
Women are more susceptible to jet lag than are men, in part because estrogen is often vulnerable to jet lag-like conditions.
Most chemical and herbal remedies, including the hormone melatonin, have not been tested nor approved by official agencies such as the U.S. Food and Drug Administration.
A recent study in hamsters showed that sildenafil (also known commercially as Viagra) aided in a 50% faster recovery from shifts comparable to eastward travel experienced by humans and was effective starting at low doses. However, this use has not been tested in humans and is considered an off-label use by the drug's manufacturers.
# Causes
When traveling across a number of time zones, the body clock will be out of sync with the destination time, as it experiences daylight and darkness contrary to the rhythms to which it has grown accustomed: the body's natural pattern is upset, as the rhythms that dictate times for eating, sleeping, hormone regulation and body temperature no longer correspond to the environment nor to each other in some cases. "Jet lag" describes the physical symptoms that occur because the body cannot immediately realign these rhythms. The speed at which the body readjusts itself to new daylight/darkness hours varies among individuals. Thus, while it may take several days for some people to readjust to a new time zone, others seem to experience little disruption to their body's natural patterns. It is, however, not common to get jet lag from a crossing of only one or two time zones.
There have been links made with jet lag and contamination of cabin air by TCP or Tricresylphosphate from contaminated engine bleed air, which supplies the cabin pressurisation system, although these have not been substantiated, and aircraft manufacturers are adament that air quality is generally high.
# Symptoms
The symptoms of jet lag can be quite varied, though on the whole, an individual may experience the following:
- Dehydration (possibly due to the dryness of air on planes)
- Loss of appetite
- Nausea and/or upset stomach
- Headaches and/or sinus irritation
- Fatigue
- Disorientation and/or grogginess
- Insomnia and/or highly irregular sleep patterns
- Irritability, irrationality
- Mild depression
Frequent changes of time zone, working long hours, or rotating shifts causes a loss of productivity, alertness, and safety costing an estimated $70 billion per year.
The condition is not linked to the length of flight, but to the transmeridian (i.e., east-west) distance traveled. Hence, a ten-hour flight between Frankfurt and Johannesburg (going south, staying roughly on the same meridian) is much less inducive of jet lag than a five-hour flight between New York and Los Angeles or vice versa. Also, the International Date Line should not be confused as contributing to jet lag, as the maximum possible disruption is plus or minus 12 hours. If the time difference between two locations is greater than 12 hours, subtract that number from 24. (For example, a 20 hour time difference equals 4 hours of jet lag.) Layovers can complicate this simple arithmetic, however.
Jet lag can be especially difficult near the north and south poles, where there are extreme periods of daylight or darkness, depending on the time of year, which often causes insomnia or hypersomnia.
# Direction of Travel
There seems to be some evidence that traveling west to east is the more disruptive. This may be because flights to the east run counter to the circadian rhythm. Most people have a circadian period which is a bit longer than 24 hours, making it easier to stay up later than to get up earlier.
It may also be that flights to the east are more likely to require people to stay awake more than one full night in order to adjust to the local time zone. For example, comparing a typical schedule for a traveler flying to the East vs a traveler flying to the West:
- Westward from London to Los Angeles, VIA BA0279, Jan 29, 2008. Time zone difference 8 hours.
- Eastward from Los Angeles to London, VIA BA0278, Jan 29, 2008.
The first scenario is equivalent to staying up all night and going to bed at 6am the next day—8 hours later than usual. But the second scenario (eastward) is equivalent to staying up all night and going to bed at 2pm the next day—16 hours after the time one would otherwise have gone to bed.
# Net Lag
People depending of updated information from other time zones, may suffer from biological clock variations causing them to be less time adjusted to the social routines of the surrounding geographical region and may suffer from similar symptoms of jet lag during the adaptation period. | Jet lag
Template:DiseaseDisorder infobox
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Jet lag, also jetlag or jet-lag, is a physiological condition which is a consequence of alterations to the circadian rhythm. Such disturbances may result from shift work, daylight saving time, altered day length, or, as the name implies, transmeridian travel (as on a jet plane). They are known as desynchronosis, dysrhythmia, dyschrony, jet lag, or jet syndrome. The condition is generally believed to be the result of disruption of the "light/dark" cycle that entrains the body's circadian rhythm. It can be exacerbated by environmental factors.
The condition of jet lag may last many days, and medical experts have deemed that a recovery rate of "one day per time zone" is a fair guideline. Good sleep hygiene promotes rapid recovery from jet lag: in fact sleep, relaxation, moderate exercise, and sensible diet seem to be the simplest recovery methods.
However, since the experience of jet lag varies among individuals, it is difficult to assess the efficacy of any single remedy. Age may also be a factor on the severity of jet lag, as younger people will suffer worse jet lag than older people would.[1]
Women are more susceptible to jet lag than are men, in part because estrogen is often vulnerable to jet lag-like conditions.[2][3]
Most chemical and herbal remedies, including the hormone melatonin, have not been tested nor approved by official agencies such as the U.S. Food and Drug Administration.
A recent study in hamsters showed that sildenafil (also known commercially as Viagra) aided in a 50% faster recovery from shifts comparable to eastward travel experienced by humans and was effective starting at low doses.[4] However, this use has not been tested in humans and is considered an off-label use by the drug's manufacturers.
# Causes
When traveling across a number of time zones, the body clock will be out of sync with the destination time, as it experiences daylight and darkness contrary to the rhythms to which it has grown accustomed: the body's natural pattern is upset, as the rhythms that dictate times for eating, sleeping, hormone regulation and body temperature no longer correspond to the environment nor to each other in some cases. "Jet lag" describes the physical symptoms that occur because the body cannot immediately realign these rhythms. The speed at which the body readjusts itself to new daylight/darkness hours varies among individuals. Thus, while it may take several days for some people to readjust to a new time zone, others seem to experience little disruption to their body's natural patterns. It is, however, not common to get jet lag from a crossing of only one or two time zones.
There have been links made with jet lag and contamination of cabin air by TCP or Tricresylphosphate from contaminated engine bleed air, which supplies the cabin pressurisation system, although these have not been substantiated, and aircraft manufacturers are adament that air quality is generally high.[5][6][7]
# Symptoms
The symptoms of jet lag can be quite varied, though on the whole, an individual may experience the following:[8]
- Dehydration (possibly due to the dryness of air on planes)
- Loss of appetite
- Nausea and/or upset stomach
- Headaches and/or sinus irritation
- Fatigue
- Disorientation and/or grogginess
- Insomnia and/or highly irregular sleep patterns
- Irritability, irrationality
- Mild depression
Frequent changes of time zone, working long hours, or rotating shifts causes a loss of productivity, alertness, and safety costing an estimated $70 billion per year.[9]
The condition is not linked to the length of flight, but to the transmeridian (i.e., east-west) distance traveled. Hence, a ten-hour flight between Frankfurt and Johannesburg (going south, staying roughly on the same meridian) is much less inducive of jet lag than a five-hour flight between New York and Los Angeles or vice versa. Also, the International Date Line should not be confused as contributing to jet lag, as the maximum possible disruption is plus or minus 12 hours. If the time difference between two locations is greater than 12 hours, subtract that number from 24. (For example, a 20 hour time difference equals 4 hours of jet lag.) Layovers can complicate this simple arithmetic, however.
Jet lag can be especially difficult near the north and south poles, where there are extreme periods of daylight or darkness, depending on the time of year, which often causes insomnia or hypersomnia.
# Direction of Travel
There seems to be some evidence that traveling west to east is the more disruptive. This may be because flights to the east run counter to the circadian rhythm.[10] Most people have a circadian period which is a bit longer than 24 hours, making it easier to stay up later than to get up earlier.
It may also be that flights to the east are more likely to require people to stay awake more than one full night in order to adjust to the local time zone. For example, comparing a typical schedule for a traveler flying to the East vs a traveler flying to the West:
- Westward from London to Los Angeles, VIA BA0279, Jan 29, 2008. Time zone difference 8 hours.
- Eastward from Los Angeles to London, VIA BA0278, Jan 29, 2008.
The first scenario is equivalent to staying up all night and going to bed at 6am the next day—8 hours later than usual. But the second scenario (eastward) is equivalent to staying up all night and going to bed at 2pm the next day—16 hours after the time one would otherwise have gone to bed.
# Net Lag
People depending of updated information from other time zones, may suffer from biological clock variations causing them to be less time adjusted to the social routines of the surrounding geographical region and may suffer from similar symptoms of jet lag during the adaptation period. | https://www.wikidoc.org/index.php/Jet-lag | |
8c6dd12ab7e11dec44ccda0a12c628d6ede8e6a9 | wikidoc | KHDRBS1 | KHDRBS1
KH domain-containing, RNA-binding, signal transduction-associated protein 1 is a protein that in humans is encoded by the KHDRBS1 gene.
This gene encodes a member of the K homology domain-containing, RNA-binding, signal transduction-associated protein family. The encoded protein appears to have many functions and may be involved in a variety of cellular processes, including alternative splicing, cell cycle regulation, RNA 3'-end formation, tumorigenesis, and regulation of human immunodeficiency virus gene expression.
# Function
Sam68 (the Src-Associated substrate in Mitosis of 68 kDa) is officially called KHDRBS1 (KH domain containing, RNA binding, signal transduction associated 1). Sam68 is a KH-type RNA binding protein that recognizes U(U/A)AA direct repeats with relative high affinity. Sam68 is predominantly nuclear and its major function in the nucleus is to regulate alternative splicing by recognizing RNA sequences neighboring the included/excluded exon(s). Direct evidence for the involvement of Sam68 in alternative splicing has been shown in promoting the inclusion of the variable exon 5 (v5) in CD44 correlating with cell migration potential. In addition, Sam68 in conjunction with hnRNPA1 influences the choice of the alternative 5' splice sites of Bcl-x regulating pro-survival and apoptotic pathways. The role of Sam68 was further highlighted in spinal muscular atrophy (SMA), as Sam68 promotes the skipping of exon 7 leading to a non-functional SMN2 protein. Sam68 was demonstrated to be involved in the alternative splicing of mRNAs implicated in normal neurogenesis using splicing-sensitive microarrays. Sam68 was also shown to participate in the epithelial-to-mesenchymal transition by regulating the alternative splicing of SF2/ASF. Sam68 was shown to regulate the activity-dependent alternative splicing of the neurexin-1 in the central nervous system with implications for neurodevelopment disorders. Sam68 influences alternative splicing of the mTOR kinase contributing to the lean phenotype observed in the Sam68 deficient mice.
The RNA binding activity of Sam68 is regulated by post-translational modifications such that Sam68 is often referred to as a STAR (Signal Transduction Activator of RNA) protein by which signals from growth factors or soluble tyrosine kinases, such as Src family kinases, act to regulate cellular RNA processes such as alternative splicing. For example, the Sam68-dependent CD44 alternative splicing of exon v5 is regulated by ERK phosphorylation of Sam68 and Bcl-x alternative splicing is regulated by the p59fyn-dependent phosphorylation of Sam68. Sam68 is also downstream of the epidermal growth factor receptor (EGFR), hepatocyte growth factor (HGF)/Met receptor (c-Met), leptin and tumor necrosis factor (TNF) receptors. While the role of Sam68 in these pathways is slowly emerging much remains to be determined. Sam68 has also been shown to re-localize in the cytoplasm near the plasma membrane, where it functions to transport and regulate the translation of certain mRNAs and regulates cell migration.
# Gene knockout studies
Sam68-deficient mice were generated by targeted disruption of exons 4-5 of the sam68 gene, which encode the functional region of the KH domain. The genotypes of the offspring from heterozygote intercrosses exhibited a Mendelian segregation at E18.5. Despite the lack of visible deformity, many of the Sam68-/- pups died at birth of unknown causes. Sam68+/- mice were phenotypically normal and Sam68-/- pups that survived the peri-natal period invariably lived to old age. Sam68-/- mice weighed less than Sam68+/+ littermates and magnetic resonance imaging analysis confirmed that young Sam68-/- mice exhibited a profound reduction in adiposity, although food intake was similar. Moreover, Sam68-/- mice were protected against dietary-induced obesity. Sam68 deficient preadipocytes (3T3-L1 cells) had impaired adipogenesis and Sam68-/- mice had ~45% less adult derived stem cells (ADSCs) in their stromal vascular fraction (SVF) from WAT.
Sam68-/- mice did not develop tumors and showed no immunological or other major illnesses. Sam68-/- mice did, however, have difficulty breeding due to male infertility and female subfertility. The Sam68-null mice exhibited motor coordination defects and fell from the rotating drum at lower speeds and prematurely compared to the wild-type controls. Sam68-/- mice are protected against age-induced osteoporosis. Using the mammary tumor virus-polyoma middle T-antigen (MMTV-PyMT) mouse model of mammary tumorigenesis, it was shown that reduced Sam68 expression decreases tumor burden and metastasis. Kaplan-Meier curves showed that loss of one sam68 allele (PyMT; Sam68+/-) was associated with a significant delay in the onset of palpable tumors and a significant reduction in tumor multiplicity. These findings suggest that Sam68 is required for PyMT-induced mammary tumorigenesis. The knockdown of Sam68 expression in PyMT-derived mammary cells reduced the number of lung tumor foci in athymic mice, suggesting that Sam68 is also required for mammary tumor metastasis. The knockdown of Sam68 delayed LNCaP prostate cancer cells proliferation. The roles of Sam68 in cancer have been reviewed. | KHDRBS1
KH domain-containing, RNA-binding, signal transduction-associated protein 1 is a protein that in humans is encoded by the KHDRBS1 gene.[1][2]
This gene encodes a member of the K homology domain-containing, RNA-binding, signal transduction-associated protein family. The encoded protein appears to have many functions and may be involved in a variety of cellular processes, including alternative splicing, cell cycle regulation, RNA 3'-end formation, tumorigenesis, and regulation of human immunodeficiency virus gene expression.[3]
# Function
Sam68 (the Src-Associated substrate in Mitosis of 68 kDa) is officially called KHDRBS1 (KH domain containing, RNA binding, signal transduction associated 1). Sam68 is a KH-type RNA binding protein that recognizes U(U/A)AA direct repeats with relative high affinity.[4][5] Sam68 is predominantly nuclear and its major function in the nucleus is to regulate alternative splicing by recognizing RNA sequences neighboring the included/excluded exon(s). Direct evidence for the involvement of Sam68 in alternative splicing has been shown in promoting the inclusion of the variable exon 5 (v5) in CD44 correlating with cell migration potential.[6][7] In addition, Sam68 in conjunction with hnRNPA1 influences the choice of the alternative 5' splice sites of Bcl-x regulating pro-survival and apoptotic pathways.[8] The role of Sam68 was further highlighted in spinal muscular atrophy (SMA), as Sam68 promotes the skipping of exon 7 leading to a non-functional SMN2 protein.[9] Sam68 was demonstrated to be involved in the alternative splicing of mRNAs implicated in normal neurogenesis using splicing-sensitive microarrays.[10] Sam68 was also shown to participate in the epithelial-to-mesenchymal transition by regulating the alternative splicing of SF2/ASF.[9] Sam68 was shown to regulate the activity-dependent alternative splicing of the neurexin-1 in the central nervous system with implications for neurodevelopment disorders.[11] Sam68 influences alternative splicing of the mTOR kinase contributing to the lean phenotype observed in the Sam68 deficient mice.[12]
The RNA binding activity of Sam68 is regulated by post-translational modifications such that Sam68 is often referred to as a STAR (Signal Transduction Activator of RNA) protein by which signals from growth factors or soluble tyrosine kinases, such as Src family kinases, act to regulate cellular RNA processes such as alternative splicing.[13] For example, the Sam68-dependent CD44 alternative splicing of exon v5 is regulated by ERK phosphorylation of Sam68[7] and Bcl-x alternative splicing is regulated by the p59fyn-dependent phosphorylation of Sam68.[8] Sam68 is also downstream of the epidermal growth factor receptor (EGFR),[14] hepatocyte growth factor (HGF)/Met receptor (c-Met),[15] leptin[16] and tumor necrosis factor (TNF) receptors.[17] While the role of Sam68 in these pathways is slowly emerging much remains to be determined. Sam68 has also been shown to re-localize in the cytoplasm near the plasma membrane, where it functions to transport and regulate the translation of certain mRNAs[18] and regulates cell migration.[14]
# Gene knockout studies
Sam68-deficient mice were generated by targeted disruption of exons 4-5 of the sam68 gene, which encode the functional region of the KH domain.[19] The genotypes of the offspring from heterozygote intercrosses exhibited a Mendelian segregation at E18.5. Despite the lack of visible deformity, many of the Sam68-/- pups died at birth of unknown causes.[19] Sam68+/- mice were phenotypically normal and Sam68-/- pups that survived the peri-natal period invariably lived to old age. Sam68-/- mice weighed less than Sam68+/+ littermates and magnetic resonance imaging analysis confirmed that young Sam68-/- mice exhibited a profound reduction in adiposity, although food intake was similar.[12] Moreover, Sam68-/- mice were protected against dietary-induced obesity.[12] Sam68 deficient preadipocytes (3T3-L1 cells) had impaired adipogenesis and Sam68-/- mice had ~45% less adult derived stem cells (ADSCs) in their stromal vascular fraction (SVF) from WAT.[12]
Sam68-/- mice did not develop tumors and showed no immunological or other major illnesses. Sam68-/- mice did, however, have difficulty breeding due to male infertility[18][19] and female subfertility.[20] The Sam68-null mice exhibited motor coordination defects and fell from the rotating drum at lower speeds and prematurely compared to the wild-type controls.[21] Sam68-/- mice are protected against age-induced osteoporosis.[19] Using the mammary tumor virus-polyoma middle T-antigen (MMTV-PyMT) mouse model of mammary tumorigenesis, it was shown that reduced Sam68 expression decreases tumor burden and metastasis.[22] Kaplan-Meier curves showed that loss of one sam68 allele (PyMT; Sam68+/-) was associated with a significant delay in the onset of palpable tumors and a significant reduction in tumor multiplicity. These findings suggest that Sam68 is required for PyMT-induced mammary tumorigenesis. The knockdown of Sam68 expression in PyMT-derived mammary cells reduced the number of lung tumor foci in athymic mice, suggesting that Sam68 is also required for mammary tumor metastasis. The knockdown of Sam68 delayed LNCaP prostate cancer cells proliferation.[23] The roles of Sam68 in cancer have been reviewed.[24] | https://www.wikidoc.org/index.php/KHDRBS1 | |
e17b0727c69088b3e2f14480e4d193b967f13319 | wikidoc | KIR2DL4 | KIR2DL4
Killer cell immunoglobulin-like receptor 2DL4 is a protein that in humans is encoded by the KIR2DL4 gene.
# Function
Killer cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed by natural killer cells and subsets of CD8+ T cells. The KIR genes are polymorphic and highly homologous and they are found in a cluster on chromosome 19q13.4 within the 1 Mb leukocyte receptor complex (LRC). The gene content of the KIR gene cluster varies among haplotypes, although several "framework" genes are found in all haplotypes (KIR3DL3, KIR3DP1, KIR3DL4, KIR3DL2). The KIR proteins are classified by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM), while KIR proteins with the short cytoplasmic domain lack the ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals. The ligands for several KIR proteins are subsets of HLA class I molecules; thus, KIR proteins are thought to play an important role in regulation of the immune response. This gene is one of the "framework" loci that is present on all haplotypes. Alternative splicing results in multiple transcript variants.
The only so far reported ligand of KIR2DL4 is the non-classical HLA class 1 gene HLA-G, leading to the inhibition of the cytolytic NK cell function. | KIR2DL4
Killer cell immunoglobulin-like receptor 2DL4 is a protein that in humans is encoded by the KIR2DL4 gene.[1][2]
# Function
Killer cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed by natural killer cells and subsets of CD8+ T cells.[3] The KIR genes are polymorphic and highly homologous and they are found in a cluster on chromosome 19q13.4 within the 1 Mb leukocyte receptor complex (LRC). The gene content of the KIR gene cluster varies among haplotypes, although several "framework" genes are found in all haplotypes (KIR3DL3, KIR3DP1, KIR3DL4, KIR3DL2). The KIR proteins are classified by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM), while KIR proteins with the short cytoplasmic domain lack the ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals. The ligands for several KIR proteins are subsets of HLA class I molecules; thus, KIR proteins are thought to play an important role in regulation of the immune response. This gene is one of the "framework" loci that is present on all haplotypes. Alternative splicing results in multiple transcript variants.[2]
The only so far reported ligand of KIR2DL4 is the non-classical HLA class 1 gene HLA-G, leading to the inhibition of the cytolytic NK cell function.[3] | https://www.wikidoc.org/index.php/KIR2DL4 | |
6460d0f64e35de6eaa46301a2c4cd2ec1938d49c | wikidoc | KIRREL3 | KIRREL3
Kin of IRRE-like protein 3 (KIRREL3) also known as kin of irregular chiasm-like protein 3 or NEPH2 is a protein that in humans is encoded by the KIRREL3 gene.
NEPH2 is a member of the NEPH protein family of transmembrane proteins, which includes NEPH1 (KIRREL) and NEPH3 (KIRREL2). The NEPH proteins can interact with nephrin and CASK.
# Function
NEPH2 has been implicated in synapse formation. Disruption of KIRREL3 gene function had been associated with abnormal brain function.
NEPH1 and NEPH2 are involved in the blood filtration function of the kidney and are located in the slit diaphragm. | KIRREL3
Kin of IRRE-like protein 3 (KIRREL3) also known as kin of irregular chiasm-like protein 3 or NEPH2 is a protein that in humans is encoded by the KIRREL3 gene.[1]
NEPH2 is a member of the NEPH protein family of transmembrane proteins, which includes NEPH1 (KIRREL) and NEPH3 (KIRREL2). The NEPH proteins can interact with nephrin and CASK.
# Function
NEPH2 has been implicated in synapse formation.[2] Disruption of KIRREL3 gene function had been associated with abnormal brain function.[3]
NEPH1 and NEPH2 are involved in the blood filtration function of the kidney and are located in the slit diaphragm.[4] | https://www.wikidoc.org/index.php/KIRREL3 | |
6ef943b826e04e5bf744dff376d08757c74d0777 | wikidoc | KREMEN1 | KREMEN1
Kremen protein 1 is a protein that in humans is encoded by the KREMEN1 gene. Kremen1 is conserved in chordates including amphioxus and most vertebrate species. The protein is a type I transmembrane receptor of ligands Dickkopf1, Dickkopf2, Dickkopf3, Dickkopf4, EpCAM and Rspondin1.
# Function
This gene encodes a high-affinity dickkopf homolog 1 (DKK1) transmembrane receptor that functionally cooperates with DKK1 to block wingless (WNT)/beta-catenin signaling. The encoded protein is a component of a membrane complex that modulates canonical WNT signaling through lipoprotein receptor-related protein 6 (LRP6). It contains extracellular kringle, WSC, and CUB domains. Alternatively spliced transcript variants encoding distinct isoforms have been observed for this gene.
Kremen1 also has a function in the induction of cell death by apoptosis. This proapototic activity is conditional and depends on the absence of ligand Dickkopf1. These observations led to the classification of this protein as a Dependence Receptor.
A mouse knock out of Kremen1 and its paralog Kremen2 is viable and fertile. | KREMEN1
Kremen protein 1 is a protein that in humans is encoded by the KREMEN1 gene.[1][2] Kremen1 is conserved in chordates including amphioxus[3] and most vertebrate species.[4] The protein is a type I transmembrane receptor of ligands Dickkopf1,[5] Dickkopf2, Dickkopf3, Dickkopf4, EpCAM[6] and Rspondin1.
# Function
This gene encodes a high-affinity dickkopf homolog 1 (DKK1) transmembrane receptor that functionally cooperates with DKK1 to block wingless (WNT)/beta-catenin signaling. The encoded protein is a component of a membrane complex that modulates canonical WNT signaling through lipoprotein receptor-related protein 6 (LRP6). It contains extracellular kringle, WSC, and CUB domains. Alternatively spliced transcript variants encoding distinct isoforms have been observed for this gene.[2]
Kremen1 also has a function in the induction of cell death by apoptosis.[4] This proapototic activity is conditional and depends on the absence of ligand Dickkopf1.[4] These observations led to the classification of this protein as a Dependence Receptor.
A mouse knock out of Kremen1 and its paralog Kremen2 is viable and fertile.[7] | https://www.wikidoc.org/index.php/KREMEN1 | |
8d6b7fb4649bb37c886a47787a0e37a6d9e20867 | wikidoc | Kahweol | Kahweol
Coffea (coffee) is a large genus (containing more than 90 species) of flowering plants in the family Rubiaceae. They are shrubs or small trees, native to subtropical Africa and southern Asia. Seeds of several species are the source of the beverage 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), 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', which is smaller and rounder than a normal coffee bean. Some claim that peaberries have a different flavor profile in the cup, while others dispute this. Either way, it is often 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 (butterfly and moth) species including Dalcera abrasa, Turnip Moth and some members of the genus Endoclita including E. damor and E. malabaricus.
## 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.
# Chemistry: Green-Coffee-Bean
In this paragraph the expression “green coffee bean” refers to both mature and immature coffee beans, having been processed by wet or dry method for removing the pulp and mucilage, with an intact wax layer on the outer surface, a green (immature) and brown to yellow colour, and weight of 300 mg to 330 mg / dried coffee bean. Non-volatile and volatile compounds of green coffee beans are responsible for their attraction of insects but also distraction of animals preventing them from eating the coffee fruit and beans. Further, both non-volatile and volatile compounds are contributing to the flavor of the roasted coffee bean. Among the non-volatile compounds nitrogenous compounds together with carbohydrates are of major importance for the full aroma of roasted coffee and its biological action. The nitrogenous compound are consisting of alkaloids, trigonelline, proteins and free amino acids.
Non-volatile Alkaloids
Caffeine (1,3,7-trimethyl-xanthine) is the most important molecule of the alkaloids being present in green and roasted coffee beans. Dried green coffee beans have a weight of 300 mg to 330 mg. The content of caffeine is between 1 % (w/w) and 2,5 % (w/w of dry green coffee). The content of caffeine does not change during maturation of green coffee beans . Lower concentrations of theophylline, theobromine, paraxanthine, liberine, and methylliberine can be found. The concentration of theophylline, a major alkaloid of green tea, is gradually reduced along the roasting time of green coffee(15 min, 230 degrees Celsius) whereas the other alkalois are not changed . The solubility of caffeine in water increases with temperature and with the addition of chlorogenic acids, citric acid, tartic acid, which all are present in green coffee beans; e.g. 1 g caffeine dissolves in 46 mL of water at room temperature, and 5,5 mL at 80 degrees Celsius . The xanthine alkaloides are odorless but have a bitter taste in water, which however is masked by organic acids being present in green coffee.
Trigonelline (N-methyl-nicotinate) is a derivative of vitamine B6 with a low bitter taste compared to caffeine. In green coffee beans the content is between 0,6 % (w/w) and 1 % (w/w). At roasting temperature (230 degrees Celsius) trigonelline is degraded to nicotinic acid by 85% leaving little amounts of the unchanged molecule in the roasted beans. In green coffee beans, trigonelline is synthetised from nicotinic acid (pyridinium-3-carboxylic acid) by methylation from methionine, a sulfur containing amino acid . Mutagenic activity of trigonelline has been reported .
Non-volatile Proteins
Proteins are accounting for 8% (w/w) to 12% (w/w) of dried green coffee beans, presenting a valuable source of amino acids. Major part of the proteins are consisting of 11-S-storage proteins (alpha - component of 32 kDa, beta – component of 22 kDa), which are degraded during maturation of green coffee beans to free amino acids. Further, 11-S-storage proteins are degraded to the individual amino acids under roasting temperature and thus being an additional source of bitter components due to generation of maillard products . Water boiling temperature, oxygene and acid pH 2.0 to pH 4.5 are degrading 11-S-storage–proteins of geen coffee beans to low molecular weight peptides and amino acids. The degradation is accelerated in the presence of organic acids such as chlorogenic acids and their derivatives. Other proteins are consisting of enzymes such as catalase, and polyphenoloxydase which are important for the maturation of green coffee beans. Mature coffee contains free amino acids (4.0 mg amino acid / g robusta coffee and up to 4 .5 mg amino acid /g arabica coffee). In arabica, alanine is the amino acid with the highest concentration, i.e. 1.2 mg / g followed by asparagine of 0.66 mg/g, whereas in in robusta alanine is present with 0.8 mg/g and asparagine with 0.36 mg/g ; . Free hydrophobic amino acids being present in fresh green coffee beans are contributing to the unpleasant bitter vomiting organoleptic taste making it impossible to prepare a beverage with such compounds. The concentrations of free hydrophobic amino acids in fresh geen coffee from Peru have been determined as follows: isoleucine 81 mg /kg, leucine 100 mg/kg, valine 93 mg/kg, tyrosine 81 mg/kg, phenylalanine 133 mg /kg. The concentration of gamma-amino-butyric-acid, a neurotransmitter in the CNS, has been determined between 143 mg/ kg and 703 mg/kg in green coffee beans from Tanzania . Roasted coffee beans literally do not contain any free amino acid. Amino acids from geen coffee beans are degraded under roasting temperature to Maillard products, i.e. reaction products between the aldehyde group of sugar (aldo-hexose) and the alpha-amino-group of the amino acids. Further, diketopiperazines, e.g. cyclo(proline-proline), cyclo(proline-leucine), cyclo(proline-isoleucine), are generated from the corresponding amino acids, being the major source of bitter taste of roasted coffee . The bitter perception of diketopiperazines starts around 20 mg/ 1 liter water. The content of diketopiperazines in espresso is about 20 mg to 30 mg which is responsible for the bitter taste perception of an espresso.
Non-volatile Carbohydrates
Green coffee beans are a valuable source of carbohydrates which make up about 50 % of the dry weight of green coffee beans. The carbohydrate fraction of green coffee is dominated by polysaccharides such as arabinogalactan, galactomanan, and cellulose contributing to the tasteless flavor of green coffee. Arabinogalactan is making up to 17 % of dry weight of green coffee beans with a molecular weight of 90 kDa to 200 kDa. It is composed of beta-1-3-linked galactan main chain with frequent members of arabinose (pentose) and galactose (hexose) residues at the side chains comprising immunomodulating properties by stimulating the celluar defence system (Th-1 response) of the body. Mature brown to yellow coffee beans contain less residues of galactose and arabinose at the side chain of the polysaccharides, making the green coffee bean more resistant against physical brake down and less soluble in water .The molecular weight of arabiniogalactan is higher than from other plants, making an improvement of the cellular defence system of the digestive tract compared to arabinogalactan with lower molecular weight ).Free monosaccharides are present in mature brown to yellow yellow green coffee beans. The free part of monosaccharides contains sucrose (gluco-fructose) up to 9000 mg/ 100g of arabica green coffee bean, a lower amount in robustas, i.e. 4500 mg/100g. In arabica green coffee beans the content of free glucose was 30 mg to 38 mg / 100 g, free fructose 23 mg to 30 mg/ 100 g; free galactose 35 mg/ 100g and mannitol 50 mg/100g dried coffee beans, respectively. Mannitol is a powerful scavenger for hydroxy redicals which are generated during the peroxydation of lipids of biological membranes .
Non-volatile Lipids
Lipids are non-polar, hydrophobic molecules and not soluble in water. Lipids are comprising linoleic acid, plamitic acid,oleic acid, stearic acid, arachidic acid, diterpenes, triglycerides, unsaturated long-chain fatty acids, esters between the hydroxy group of triglycerol and the carboxyl group of fatty acids and amides. The total content of lipids from dried green coffee is between 11,7 g to 14 g / 100 g . Lipids are present on the surface and in the interior matrix of green coffee beans. On the surface they include derivatives of carboxylic acid-5-hydroxytryptamides with an amid bond to fatty acids (unsaturated C6 to C24) making up to 3% (w/w) of total lipid content or 1200 to 1400 microgram / g dried green coffee bean. Such compounds are building up a wax cover on the surface of the coffee bean (200 mg to 300 mg lipids / 100 g dried green coffee beans) protecting the interior matrix against oxydation and immigration of insects and diffusion of low molecular compounds generated during the wet processing fermentation from the fermentation brew into the tissue of the green coffee bean. Further, such molecules are generating antioxydative activity due to their chemical structure . Lipds of the interior tissue are triglycerids, linoleic acid (46% of total free lipids), palmitic acid (30% to 35% of total free lipids), and esters. Arabica have a highter content of lipids (13,5 g to 17,4 g lipids/100 g dried green coffee beans) than robustas (9,8 g to 10,7 g lipids / 100 g dried green coffee beans).
The content of diterpenes is about 20% of the lipid fraction. Diterpenes are comprising e.g. cafestol, kahweol, 16-O-methyl-kafestol, cafestal, kahweal. Diterpenes are known for their in-vitro protection of liver tissue against chemical oxydation .In coffee oil from green coffee beans the diterpenes are ersterfied with saturated long chain fatty acids.
Non-volatine Chlorogenic acids
Chlorogenic acids belong to a group consisting of compounds which are known as polyphenols which are antioxydants. The content of chlorogeneic acid in dried green coffee beans of robusta is 65 mg/ g and of arabica 140 mg / g, depending on time of harvesting. At roasting temperature chlorogenic acids are destroyed by more than 70% or leaving a residue of less than 30 mg/g roasted coffee bean. In contrast to green coffee, green tea contains an average of 85 mg polyphenols/g. Therefor chlorogenic acids could be a valuable inexpensive source of antioxydants. Chlorogenic acids are homologous compounds comprising caffeic acid, ferulic acid and 3,4 dimethoxycinnamic acid which are connected by an ester-bond to the hydroxy groups of quinic acid (1alpha, 3R, 4 alpha, 5R-tetrahydroxy-cyclohexane carboxylic acid) The anti-oxydation capacity of Chlorogenic acid is more potent than of ascorbic acid (vitamine-C) or mannitol, which is a selective hydroxy-radical scavenger . Chlorgenic acids have a bitter taste in low concentrations such as 50 mg / 1 L water. At higher concentrations of 1 g/ 1 L water they appear with a sour taste. Chlorogenic acid increase the solubility of caffeine and are imoprtant modulaters of taste.
Volatile compounds of Green Coffee
Volatile compounds of green coffee beans are comprising short chain fatty acids, aldehydes, and nitrogen containing aromatic molecules such as derivatives of pyrazines green-herbeaceous-earthy odor. Briefly, such volatile compounds are responsible for the unpleasant odor and taste of green coffee being capable of causing nausea and vomiting on inspiration of the odor of ground green coffee beans or ingestion of a beverage made up by pulverised green coffee beans. Due to this nauseating odor green coffee beens have never been used first hand for the preparation of a refreshing beverage, which in fact would cause vomiting, although green coffee beans are containing the same amount of caffeine as rosted coffee. On roasting of green coffee beans other molecules with the typical pleasant aroma of coffee are generated, which is not present in fresh green coffee. Other tried to neutralise or transform the nauseating odor-molecules of green coffee beans into innovative flavor by fermentation of the intact mature brown to yellow coffee bean similar to the wet processing of the mature coffee fruit . However such fermented green coffee beans must be further roasted in order to obtain an organoleptic accepted beverage based on coffee. On roasting major part of the unpleasant tasting volatile compounds are neutralised. Unfortunately other important molecules such as antioxydants and vitamines being present in green coffee are destroyed. Such volatile compounds with nauseating odor for humans which have been identified are e.g. acetic acid (pungent, unpleasant odor); propionic acid (odor of sour milk, or butter); butanoic acid (odor of rancid butter, present in green coffee with 2 mg/100 g coffee beans); pentanoic acid (unpleasant fruity flavor, present in green coffe with 40 mg/100 g coffee beans); hexanoic acid (fatty-rancid odor), heptanoic acid (fatty odor); octanoic acid ( repulsive oily rancid odor); nonanoic acid (mild nut-like fatty odor); decanoic acid (sour repulsive odor); and derivatives of such fatty acids. 3-methyl-valericacid (sour, green-herbaceous, unpleasant odor); acetaldehyde (pungent-nauseating odor, even in high dilutions; present in dried green coffee beans with 5 mg/1 kg); propanal (chocking effect on respiratory system, penetrating-nauseating), butanal (nauseating effect; present in dried green coffee beans with 2 to 7 mg /1 kg); pentanal or valerianic aldehyde very repulsive nauseating effect .
Health properties of Green Coffee
Green coffee beans are a rich source of antioxydants such as polyphenols and mannitol with a high protecting effect against chemical peroxydation. The high content of arabinogalactans can stimulate the immune system (e.g. macrophage)of the gastrointestinal tract and might help to overcome problems of colon irritabile or inflamabel bowl diseases. Extracts of green coffee have been shown to improve varoreactivity in humans . Unfortunately, green coffee can only consumed by humans thru coated capsules because of the nauseating odor of the volatile compounds of – healthy – green coffee beans. | Kahweol
Coffea (coffee) is a large genus (containing more than 90 species)[1] of flowering plants in the family Rubiaceae. They are shrubs or small trees, native to subtropical Africa and southern Asia. Seeds of several species are the source of the beverage 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), 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', which is smaller and rounder than a normal coffee bean. Some claim that peaberries have a different flavor profile in the cup, while others dispute this. Either way, it is often 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 (butterfly and moth) species including Dalcera abrasa, Turnip Moth and some members of the genus Endoclita including E. damor and E. malabaricus.
## 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.[2]
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.[2]
# Chemistry: Green-Coffee-Bean
In this paragraph the expression “green coffee bean” refers to both mature and immature coffee beans, having been processed by wet or dry method for removing the pulp and mucilage, with an intact wax layer on the outer surface, a green (immature) and brown to yellow colour, and weight of 300 mg to 330 mg / dried coffee bean. Non-volatile and volatile compounds of green coffee beans are responsible for their attraction of insects but also distraction of animals preventing them from eating the coffee fruit and beans. Further, both non-volatile and volatile compounds are contributing to the flavor of the roasted coffee bean. Among the non-volatile compounds nitrogenous compounds together with carbohydrates are of major importance for the full aroma of roasted coffee and its biological action. The nitrogenous compound are consisting of alkaloids, trigonelline, proteins and free amino acids.
Non-volatile Alkaloids
Caffeine (1,3,7-trimethyl-xanthine) is the most important molecule of the alkaloids being present in green and roasted coffee beans. Dried green coffee beans have a weight of 300 mg to 330 mg. The content of caffeine is between 1 % (w/w) and 2,5 % (w/w of dry green coffee). The content of caffeine does not change during maturation of green coffee beans [3]. Lower concentrations of theophylline, theobromine, paraxanthine, liberine, and methylliberine can be found. The concentration of theophylline, a major alkaloid of green tea, is gradually reduced along the roasting time of green coffee(15 min, 230 degrees Celsius) whereas the other alkalois are not changed [4]. The solubility of caffeine in water increases with temperature and with the addition of chlorogenic acids, citric acid, tartic acid, which all are present in green coffee beans; e.g. 1 g caffeine dissolves in 46 mL of water at room temperature, and 5,5 mL at 80 degrees Celsius [5]. The xanthine alkaloides are odorless but have a bitter taste in water, which however is masked by organic acids being present in green coffee.
Trigonelline (N-methyl-nicotinate) is a derivative of vitamine B6 with a low bitter taste compared to caffeine. In green coffee beans the content is between 0,6 % (w/w) and 1 % (w/w). At roasting temperature (230 degrees Celsius) trigonelline is degraded to nicotinic acid by 85% leaving little amounts of the unchanged molecule in the roasted beans. In green coffee beans, trigonelline is synthetised from nicotinic acid (pyridinium-3-carboxylic acid) by methylation from methionine, a sulfur containing amino acid [6]. Mutagenic activity of trigonelline has been reported [7].
Non-volatile Proteins
Proteins are accounting for 8% (w/w) to 12% (w/w) of dried green coffee beans, presenting a valuable source of amino acids. Major part of the proteins are consisting of 11-S-storage proteins (alpha - component of 32 kDa, beta – component of 22 kDa), which are degraded during maturation of green coffee beans to free amino acids. Further, 11-S-storage proteins are degraded to the individual amino acids under roasting temperature and thus being an additional source of bitter components due to generation of maillard products [8]. Water boiling temperature, oxygene and acid pH 2.0 to pH 4.5 are degrading 11-S-storage–proteins of geen coffee beans to low molecular weight peptides and amino acids. The degradation is accelerated in the presence of organic acids such as chlorogenic acids and their derivatives. Other proteins are consisting of enzymes such as catalase, and polyphenoloxydase which are important for the maturation of green coffee beans. Mature coffee contains free amino acids (4.0 mg amino acid / g robusta coffee and up to 4 .5 mg amino acid /g arabica coffee). In arabica, alanine is the amino acid with the highest concentration, i.e. 1.2 mg / g followed by asparagine of 0.66 mg/g, whereas in in robusta alanine is present with 0.8 mg/g and asparagine with 0.36 mg/g [9]; [10]. Free hydrophobic amino acids being present in fresh green coffee beans are contributing to the unpleasant bitter vomiting organoleptic taste making it impossible to prepare a beverage with such compounds. The concentrations of free hydrophobic amino acids in fresh geen coffee from Peru have been determined as follows: isoleucine 81 mg /kg, leucine 100 mg/kg, valine 93 mg/kg, tyrosine 81 mg/kg, phenylalanine 133 mg /kg. The concentration of gamma-amino-butyric-acid, a neurotransmitter in the CNS, has been determined between 143 mg/ kg and 703 mg/kg in green coffee beans from Tanzania [11]. Roasted coffee beans literally do not contain any free amino acid. Amino acids from geen coffee beans are degraded under roasting temperature to Maillard products, i.e. reaction products between the aldehyde group of sugar (aldo-hexose) and the alpha-amino-group of the amino acids. Further, diketopiperazines, e.g. cyclo(proline-proline), cyclo(proline-leucine), cyclo(proline-isoleucine), are generated from the corresponding amino acids, being the major source of bitter taste of roasted coffee [12]. The bitter perception of diketopiperazines starts around 20 mg/ 1 liter water. The content of diketopiperazines in espresso is about 20 mg to 30 mg which is responsible for the bitter taste perception of an espresso.
Non-volatile Carbohydrates
Green coffee beans are a valuable source of carbohydrates which make up about 50 % of the dry weight of green coffee beans. The carbohydrate fraction of green coffee is dominated by polysaccharides such as arabinogalactan, galactomanan, and cellulose contributing to the tasteless flavor of green coffee. Arabinogalactan is making up to 17 % of dry weight of green coffee beans with a molecular weight of 90 kDa to 200 kDa. It is composed of beta-1-3-linked galactan main chain with frequent members of arabinose (pentose) and galactose (hexose) residues at the side chains comprising immunomodulating properties by stimulating the celluar defence system (Th-1 response) of the body. Mature brown to yellow coffee beans contain less residues of galactose and arabinose at the side chain of the polysaccharides, making the green coffee bean more resistant against physical brake down and less soluble in water [13].The molecular weight of arabiniogalactan is higher than from other plants, making an improvement of the cellular defence system of the digestive tract compared to arabinogalactan with lower molecular weight [14]).Free monosaccharides are present in mature brown to yellow yellow green coffee beans. The free part of monosaccharides contains sucrose (gluco-fructose) up to 9000 mg/ 100g of arabica green coffee bean, a lower amount in robustas, i.e. 4500 mg/100g. In arabica green coffee beans the content of free glucose was 30 mg to 38 mg / 100 g, free fructose 23 mg to 30 mg/ 100 g; free galactose 35 mg/ 100g and mannitol 50 mg/100g dried coffee beans, respectively. Mannitol is a powerful scavenger for hydroxy redicals which are generated during the peroxydation of lipids of biological membranes [15].
Non-volatile Lipids
Lipids are non-polar, hydrophobic molecules and not soluble in water. Lipids are comprising linoleic acid, plamitic acid,oleic acid, stearic acid, arachidic acid, diterpenes, triglycerides, unsaturated long-chain fatty acids, esters between the hydroxy group of triglycerol and the carboxyl group of fatty acids and amides. The total content of lipids from dried green coffee is between 11,7 g to 14 g / 100 g [16]. Lipids are present on the surface and in the interior matrix of green coffee beans. On the surface they include derivatives of carboxylic acid-5-hydroxytryptamides with an amid bond to fatty acids (unsaturated C6 to C24) making up to 3% (w/w) of total lipid content or 1200 to 1400 microgram / g dried green coffee bean. Such compounds are building up a wax cover on the surface of the coffee bean (200 mg to 300 mg lipids / 100 g dried green coffee beans) protecting the interior matrix against oxydation and immigration of insects and diffusion of low molecular compounds generated during the wet processing fermentation from the fermentation brew into the tissue of the green coffee bean. Further, such molecules are generating antioxydative activity due to their chemical structure [17]. Lipds of the interior tissue are triglycerids, linoleic acid (46% of total free lipids), palmitic acid (30% to 35% of total free lipids), and esters. Arabica have a highter content of lipids (13,5 g to 17,4 g lipids/100 g dried green coffee beans) than robustas (9,8 g to 10,7 g lipids / 100 g dried green coffee beans).
The content of diterpenes is about 20% of the lipid fraction. Diterpenes are comprising e.g. cafestol, kahweol, 16-O-methyl-kafestol, cafestal, kahweal. Diterpenes are known for their in-vitro protection of liver tissue against chemical oxydation [18].In coffee oil from green coffee beans the diterpenes are ersterfied with saturated long chain fatty acids.
Non-volatine Chlorogenic acids
Chlorogenic acids belong to a group consisting of compounds which are known as polyphenols which are antioxydants. The content of chlorogeneic acid in dried green coffee beans of robusta is 65 mg/ g and of arabica 140 mg / g, depending on time of harvesting. At roasting temperature chlorogenic acids are destroyed by more than 70% or leaving a residue of less than 30 mg/g roasted coffee bean. In contrast to green coffee, green tea contains an average of 85 mg polyphenols/g. Therefor chlorogenic acids could be a valuable inexpensive source of antioxydants. Chlorogenic acids are homologous compounds comprising caffeic acid, ferulic acid and 3,4 dimethoxycinnamic acid which are connected by an ester-bond to the hydroxy groups of quinic acid (1alpha, 3R, 4 alpha, 5R-tetrahydroxy-cyclohexane carboxylic acid) [19] The anti-oxydation capacity of Chlorogenic acid is more potent than of ascorbic acid (vitamine-C) or mannitol, which is a selective hydroxy-radical scavenger [20]. Chlorgenic acids have a bitter taste in low concentrations such as 50 mg / 1 L water. At higher concentrations of 1 g/ 1 L water they appear with a sour taste. Chlorogenic acid increase the solubility of caffeine and are imoprtant modulaters of taste.
Volatile compounds of Green Coffee
Volatile compounds of green coffee beans are comprising short chain fatty acids, aldehydes, and nitrogen containing aromatic molecules such as derivatives of pyrazines green-herbeaceous-earthy odor. Briefly, such volatile compounds are responsible for the unpleasant odor and taste of green coffee being capable of causing nausea and vomiting on inspiration of the odor of ground green coffee beans or ingestion of a beverage made up by pulverised green coffee beans. Due to this nauseating odor green coffee beens have never been used first hand for the preparation of a refreshing beverage, which in fact would cause vomiting, although green coffee beans are containing the same amount of caffeine as rosted coffee. On roasting of green coffee beans other molecules with the typical pleasant aroma of coffee are generated, which is not present in fresh green coffee. Other tried to neutralise or transform the nauseating odor-molecules of green coffee beans into innovative flavor by fermentation of the intact mature brown to yellow coffee bean similar to the wet processing of the mature coffee fruit [21]. However such fermented green coffee beans must be further roasted in order to obtain an organoleptic accepted beverage based on coffee. On roasting major part of the unpleasant tasting volatile compounds are neutralised. Unfortunately other important molecules such as antioxydants and vitamines being present in green coffee are destroyed. Such volatile compounds with nauseating odor for humans which have been identified are e.g. acetic acid (pungent, unpleasant odor); propionic acid (odor of sour milk, or butter); butanoic acid (odor of rancid butter, present in green coffee with 2 mg/100 g coffee beans); pentanoic acid (unpleasant fruity flavor, present in green coffe with 40 mg/100 g coffee beans); hexanoic acid (fatty-rancid odor), heptanoic acid (fatty odor); octanoic acid ( repulsive oily rancid odor); nonanoic acid (mild nut-like fatty odor); decanoic acid (sour repulsive odor); and derivatives of such fatty acids. 3-methyl-valericacid (sour, green-herbaceous, unpleasant odor); acetaldehyde (pungent-nauseating odor, even in high dilutions; present in dried green coffee beans with 5 mg/1 kg); propanal (chocking effect on respiratory system, penetrating-nauseating), butanal (nauseating effect; present in dried green coffee beans with 2 to 7 mg /1 kg); pentanal or valerianic aldehyde very repulsive nauseating effect [22].
Health properties of Green Coffee
Green coffee beans are a rich source of antioxydants such as polyphenols and mannitol with a high protecting effect against chemical peroxydation. The high content of arabinogalactans can stimulate the immune system (e.g. macrophage)of the gastrointestinal tract and might help to overcome problems of colon irritabile or inflamabel bowl diseases. Extracts of green coffee have been shown to improve varoreactivity in humans [23]. Unfortunately, green coffee can only consumed by humans thru coated capsules because of the nauseating odor of the volatile compounds of – healthy – green coffee beans. | https://www.wikidoc.org/index.php/Kahweol | |
245f6023349fe6cc3d059ec89f5baeb006571dd3 | wikidoc | Kalirin | Kalirin
Kalirin, also known as Huntingtin-associated protein-interacting protein (HAPIP), protein duo (DUO), or serine/threonine-protein kinase with Dbl- and pleckstrin homology domain, is a protein that in humans is encoded by the KALRN gene. Kalirin was first identified in 1997 as a protein interacting with huntingtin-associated protein 1. Is also known to play an important role in nerve growth and axonal development.
Kalirin is a member of the Dbl family of proteins and is a Rho guanine nucleotide exchange factor.
It is named after the multiple-handed Hindu goddess Kali for its ability to interact with numerous other proteins. Kalirin's other name, DUO, comes from the fact that it is 98% identical to rat DUO protein and 80.6% identical to a human protein named TRIO. Unlike TRIO, which is expressed in numerous tissues, Kalirin isoforms are mainly found in the brain.
# Clinical significance
Several isoforms of Kalirin are produced through alternative splicing. One of the isoforms, Kalirin-7, was found to be necessary for the remodeling of synapses in mature cortical neurons and is thought to be important in the development of schizophrenia, as demonstrated by adolescent development of schizophrenia-like symptoms in kalirin knockout mice. Alzheimer's disease may also be linked to kalirin-7. | Kalirin
Kalirin, also known as Huntingtin-associated protein-interacting protein (HAPIP), protein duo (DUO), or serine/threonine-protein kinase with Dbl- and pleckstrin homology domain, is a protein that in humans is encoded by the KALRN gene.[1][2] Kalirin was first identified in 1997 as a protein interacting with huntingtin-associated protein 1.[1] Is also known to play an important role in nerve growth and axonal development.[3]
Kalirin is a member of the Dbl family of proteins and is a Rho guanine nucleotide exchange factor.
It is named after the multiple-handed Hindu goddess Kali for its ability to interact with numerous other proteins. Kalirin's other name, DUO, comes from the fact that it is 98% identical to rat DUO protein and 80.6% identical to a human protein named TRIO. Unlike TRIO, which is expressed in numerous tissues, Kalirin isoforms are mainly found in the brain.
# Clinical significance
Several isoforms of Kalirin are produced through alternative splicing.[4] One of the isoforms, Kalirin-7, was found to be necessary for the remodeling of synapses in mature cortical neurons and is thought to be important in the development of schizophrenia,[5][6][7][8] as demonstrated by adolescent development of schizophrenia-like symptoms in kalirin knockout mice.[9] Alzheimer's disease may also be linked to kalirin-7.[8][10][11] | https://www.wikidoc.org/index.php/Kalirin | |
5c7d3d4eae30e77b5fa13e1705164af6a5558361 | wikidoc | Keratin | Keratin
Keratins are a family of fibrous structural proteins; tough and insoluble, they form the hard but nonmineralized structures found in reptiles, birds, amphibians and mammals. They are rivaled as biological materials in toughness only by chitin.
There are various types of keratins within a single animal.
# Variety of animal uses
Keratins are the main constituent of structures that grow from the skin:
- the α-keratins in the hair (including wool), horns, nails, claws and hooves of mammals
- the harder β-keratins found in nails and in the scales and claws of reptiles, their shells (chelonians, such as tortoise, turtle, terrapin), and in the feathers, beaks, and claws of birds. (These keratins are formed primarily in beta sheets. However, beta sheets are also found in α-keratins.)
Arthropods such as crustaceans often have parts of their armor or exoskeleton made of keratin, sometimes in combination with chitin.
The baleen plates of filter-feeding whales are made of keratin.
They can be integrated in the chitinophosphatic material that makes up the shell and setae in many brachiopods.
Keratins are also found in the gastrointestinal tracts of many animals, including roundworms (who also have an outer layer made of keratin).
Although it is now difficult to be certain, the scales, claws, some protective armour and the beaks of dinosaurs would, almost certainly, have been composed of a type of keratin.
In Crossopterygian fish, the outer layer of cosmoid scales was keratin.
# Cornification
In mammals there are soft epithelial keratins, the cytokeratins, and harder hair keratins. As certain skin cells differentiate and become cornified, pre-keratin polypeptides are incorporated into intermediate filaments. Eventually the nucleus and cytoplasmic organelles disappear, metabolism ceases and cells undergo a programmed death as they become fully keratinized.
Cells in the epidermis contain a structural matrix of keratin which makes this outermost layer of the skin almost waterproof, and along with collagen and elastin, gives skin its strength. Rubbing and pressure cause keratin to proliferate with the formation of protective calluses — useful for athletes and on the fingertips of musicians who play stringed instruments. Keratinized epidermal cells are constantly shed and replaced (see dandruff).
These hard, integumentary structures are formed by intercellular cementing of fibers formed from the dead, cornified cells generated by specialized beds deep within the skin. Hair grows continuously and feathers moult and regenerate. The constituent proteins may be phylogenetically homologous but differ somewhat in chemical structure and supermolecular organization. The evolutionary relationships are complex and only partially known. Multiple genes have been identified for the β-keratins in feathers, and this is probably characteristic of all keratins.
# Molecular biology and biochemistry
The properties which make structural proteins like keratins useful depend on their supermolecular aggregation. These depend on the properties of the individual polypeptide strands, which depend in turn on their amino acid composition and sequence. The α-helix and β-sheet motifs, and disulfide bridges, are crucial to the conformations of globular, functional proteins like enzymes, many of which operate semi-independently, but they take on a completely dominant role in the architecture and aggregation of keratins.
## Glycine and alanine
Keratins contain a high proportion of the smallest of the 20 amino acids, glycine, whose "side group" is a single hydrogen atom; also the next smallest, alanine, with a small and noncharged methyl group. In the case of β-sheets, this allows sterically-unhindered hydrogen bonding between the amino and carboxyl groups of peptide bonds on adjacent protein chains, facilitating their close alignment and strong binding. Fibrous keratin molecules can twist around each other to form helical intermediate filaments.
Limited interior space is the reason why the triple helix of the (unrelated) structural protein collagen, found in skin, cartilage and bone, likewise has a high percentage of glycine. The connective tissue protein elastin also has a high percentage of both glycine and alanine. Silk fibroin, considered a β-keratin, can have these two as 75–80% of the total, with 10–15% serine, with the rest having bulky side groups. The chains are antiparallel, with an alternating C → N orientation. A preponderance of amino acids with small, nonreactive side groups is characteristic of structural proteins, for which H-bonded close packing is more important than chemical specificity.
## Disulfide bridges
In addition to intra- and intermolecular hydrogen bonds, keratins have large amounts of the sulfur-containing amino acid cysteine, required for the disulfide bridges that confer additional strength and rigidity by permanent, thermally-stable crosslinking—a role sulfur bridges also play in vulcanized rubber. Human hair is approximately 14% cysteine. The pungent smells of burning hair and rubber are due to the sulfur compounds formed. Extensive disulfide bonding contributes to the insolubility of keratins, except in dissociating or reducing agents.
The more flexible and elastic keratins of hair have fewer interchain disulfide bridges than the keratins in mammalian fingernails, hooves and claws (homologous structures), which are harder and more like their analogs in other vertebrate classes. Hair and other α-keratins consist of α-helically-coiled single protein strands (with regular intra-chain H-bonding), which are then further twisted into superhelical ropes that may be further coiled. The β-keratins of reptiles and birds have β-pleated sheets twisted together, then stabilized and hardened by disulfide bridges.
# Silk
The silk fibroins produced by insects and spiders are often classified as keratins, though it is unclear whether they are phylogenetically related to vertebrate keratins.
Silk found in insect pupae, and in spider webs and egg casings, also has twisted β-pleated sheets incorporated into fibers wound into larger supermolecular aggregates. The structure of the spinnerets on spiders’ tails, and the contributions of their interior glands, provide remarkable control of fast extrusion. Spider silk is typically about 1 to 2 micrometres (µm) thick, compared with about 60 µm for human hair, and more for some mammals. (Hair, or fur, occurs only in mammals.) The biologically and commercially useful properties of silk fibers depend on the organization of multiple adjacent protein chains into hard, crystalline regions of varying size, alternating with flexible, amorphous regions where the chains are randomly coiled. A somewhat analogous situation occurs with synthetic polymers such as nylon, developed as a silk substitute. Silk from the hornet cocoon contains doublets about 10 µm across, with cores and coating, and may be arranged in up to 10 layers; also in plaques of variable shape. Adult hornets also use silk as a glue, as do spiders.
# Pairing
# Clinical significance
Some infectious fungi, such as those which cause athlete's foot, ringworm or the Batrachochytrium dendrobatidis (Chytrid fungus) which is killing amphibians all over the world, feed on keratin.
Diseases caused by mutations in the keratin genes include
- Epidermolysis bullosa simplex
- Ichthyosis bullosa of Siemens
- Epidermolytic hyperkeratosis
- Steatocystoma multiplex | Keratin
Keratins are a family of fibrous structural proteins; tough and insoluble, they form the hard but nonmineralized structures found in reptiles, birds, amphibians and mammals. They are rivaled as biological materials in toughness only by chitin.
There are various types of keratins within a single animal.
# Variety of animal uses
Keratins are the main constituent of structures that grow from the skin:
- the α-keratins in the hair (including wool), horns, nails, claws and hooves of mammals[verification needed]
- the harder β-keratins found in nails and in the scales and claws of reptiles, their shells (chelonians, such as tortoise, turtle, terrapin), and in the feathers, beaks, and claws of birds.[verification needed] (These keratins are formed primarily in beta sheets. However, beta sheets are also found in α-keratins.)[1]
Arthropods such as crustaceans often have parts of their armor or exoskeleton made of keratin, sometimes in combination with chitin.
The baleen plates of filter-feeding whales are made of keratin.
They can be integrated in the chitinophosphatic material that makes up the shell and setae in many brachiopods.
Keratins are also found in the gastrointestinal tracts of many animals, including roundworms (who also have an outer layer made of keratin).
Although it is now difficult to be certain, the scales, claws, some protective armour and the beaks of dinosaurs would, almost certainly, have been composed of a type of keratin.
In Crossopterygian fish, the outer layer of cosmoid scales was keratin.
# Cornification
In mammals there are soft epithelial keratins, the cytokeratins, and harder hair keratins. As certain skin cells differentiate and become cornified, pre-keratin polypeptides are incorporated into intermediate filaments. Eventually the nucleus and cytoplasmic organelles disappear, metabolism ceases and cells undergo a programmed death as they become fully keratinized.
Cells in the epidermis contain a structural matrix of keratin which makes this outermost layer of the skin almost waterproof, and along with collagen and elastin, gives skin its strength. Rubbing and pressure cause keratin to proliferate with the formation of protective calluses — useful for athletes and on the fingertips of musicians who play stringed instruments. Keratinized epidermal cells are constantly shed and replaced (see dandruff).
These hard, integumentary structures are formed by intercellular cementing of fibers formed from the dead, cornified cells generated by specialized beds deep within the skin. Hair grows continuously and feathers moult and regenerate. The constituent proteins may be phylogenetically homologous but differ somewhat in chemical structure and supermolecular organization. The evolutionary relationships are complex and only partially known. Multiple genes have been identified for the β-keratins in feathers, and this is probably characteristic of all keratins.
# Molecular biology and biochemistry
The properties which make structural proteins like keratins useful depend on their supermolecular aggregation. These depend on the properties of the individual polypeptide strands, which depend in turn on their amino acid composition and sequence. The α-helix and β-sheet motifs, and disulfide bridges, are crucial to the conformations of globular, functional proteins like enzymes, many of which operate semi-independently, but they take on a completely dominant role in the architecture and aggregation of keratins.
## Glycine and alanine
Keratins contain a high proportion of the smallest of the 20 amino acids, glycine, whose "side group" is a single hydrogen atom; also the next smallest, alanine, with a small and noncharged methyl group. In the case of β-sheets, this allows sterically-unhindered hydrogen bonding between the amino and carboxyl groups of peptide bonds on adjacent protein chains, facilitating their close alignment and strong binding. Fibrous keratin molecules can twist around each other to form helical intermediate filaments.
Limited interior space is the reason why the triple helix of the (unrelated) structural protein collagen, found in skin, cartilage and bone, likewise has a high percentage of glycine. The connective tissue protein elastin also has a high percentage of both glycine and alanine. Silk fibroin, considered a β-keratin, can have these two as 75–80% of the total, with 10–15% serine, with the rest having bulky side groups. The chains are antiparallel, with an alternating C → N orientation.[1] A preponderance of amino acids with small, nonreactive side groups is characteristic of structural proteins, for which H-bonded close packing is more important than chemical specificity.
## Disulfide bridges
In addition to intra- and intermolecular hydrogen bonds, keratins have large amounts of the sulfur-containing amino acid cysteine, required for the disulfide bridges that confer additional strength and rigidity by permanent, thermally-stable crosslinking—a role sulfur bridges also play in vulcanized rubber. Human hair is approximately 14% cysteine. The pungent smells of burning hair and rubber are due to the sulfur compounds formed. Extensive disulfide bonding contributes to the insolubility of keratins, except in dissociating or reducing agents.
The more flexible and elastic keratins of hair have fewer interchain disulfide bridges than the keratins in mammalian fingernails, hooves and claws (homologous structures), which are harder and more like their analogs in other vertebrate classes. Hair and other α-keratins consist of α-helically-coiled single protein strands (with regular intra-chain H-bonding), which are then further twisted into superhelical ropes that may be further coiled. The β-keratins of reptiles and birds have β-pleated sheets twisted together, then stabilized and hardened by disulfide bridges.
# Silk
The silk fibroins produced by insects and spiders are often classified as keratins, though it is unclear whether they are phylogenetically related to vertebrate keratins.
Silk found in insect pupae, and in spider webs and egg casings, also has twisted β-pleated sheets incorporated into fibers wound into larger supermolecular aggregates. The structure of the spinnerets on spiders’ tails, and the contributions of their interior glands, provide remarkable control of fast extrusion. Spider silk is typically about 1 to 2 micrometres (µm) thick, compared with about 60 µm for human hair, and more for some mammals. (Hair, or fur, occurs only in mammals.) The biologically and commercially useful properties of silk fibers depend on the organization of multiple adjacent protein chains into hard, crystalline regions of varying size, alternating with flexible, amorphous regions where the chains are randomly coiled.[2] A somewhat analogous situation occurs with synthetic polymers such as nylon, developed as a silk substitute. Silk from the hornet cocoon contains doublets about 10 µm across, with cores and coating, and may be arranged in up to 10 layers; also in plaques of variable shape. Adult hornets also use silk as a glue, as do spiders.
# Pairing
# Clinical significance
Some infectious fungi, such as those which cause athlete's foot, ringworm or the Batrachochytrium dendrobatidis (Chytrid fungus) which is killing amphibians all over the world, feed on keratin.
Diseases caused by mutations in the keratin genes include
- Epidermolysis bullosa simplex
- Ichthyosis bullosa of Siemens
- Epidermolytic hyperkeratosis
- Steatocystoma multiplex | https://www.wikidoc.org/index.php/Keratin | |
0ae6e260b4ffc42a4925e383ba2dfdb249293bd3 | wikidoc | Kigelia | Kigelia
Kigelia is a genus of flowering plants in the family Bignoniaceae. The genus comprises only one species, Kigelia africana, which occurs throughout tropical Africa from Eritrea and Chad south to northern South Africa, and west to Senegal and Namibia.
The genus name comes from the Mozambican Bantu name, kigeli-keia, while the common name Sausage Tree refers to the long, sausage-like fruit. Its name in Afrikaans Worsboom also means Sausage Tree, and its Arabic name means "the father of kit bags" (Roodt 1992).
It is a tree growing up to 20 m tall. The bark is grey and smooth at first, peeling on older trees. It can be as thick as 6 mm on a 15-cm branch (Roodt 1992). The wood is pale brown or yellowish, undifferentiated and not prone to cracking (Roodt 1992).
The tree is evergreen where rainfall occurs throughout the year, but deciduous where there is a long dry season. The leaves are opposite or in whorls of three, 30–50 cm long, pinnate, with six to ten oval leaflets up to 20 cm long and 6 cm broad; the terminal leaflet can be either present or absent. The flowers (and later the fruit) hang down from branches on long flexible stems (2-6 metres long). Flowers are produced in panicles; they are bell-shaped (similar to those of the african tulip tree but darker and more waxy), orange to reddish or purplish green, and about 10 cm wide. Individual flowers do not hang down but are oriented horizontally. Some birds are attracted to these flowers and the strong stems of each flower make ideal footholds. Their scent is most notable at night indicating their reliance on pollination by bats, which visit them for pollen and nectar.
The fruit is a woody berry from 30–100 cm long and up to 18 cm broad; it weighs between 5–10 kg, and hang down on long, rope-like peduncles. The fruit pulp is fibrous and pulpy, and contains numerous seeds. It is eaten by several species of mammals, including Baboons, Bushpigs, Savannah Elephants, Giraffes, Hippopotami, monkeys, and porcupines. The seeds are dispersed in their dung. The seeds are also eaten by Brown Parrots and Brown-headed Parrots, and the foliage by elephants and Greater Kudu (Joffe 2003; del Hoyo et al. 1997). Introduced specimens in Australian parks are very popular with cockatoos.
# Cultivation and uses
In African herbal medicine, the fruit is believed to be a cure for a wide range of ailments, from rheumatism, snakebites, evil spirits, syphilis, and even tornadoes (Watkins 1975). An alcoholic beverage similar to beer is also made from it. The fresh fruit is poisonous and strongly purgative; fruit are prepared for consumption by drying, roasting or fermentation (Joffe 2003; McBurney 2004). In Botswana the timber is used for makoros, yokes and oars (Roodt 1992).
The tree is widely grown as an ornamental tree in tropical regions for its decorative flowers and unusual fruit. Planting sites should be selected carefully, as the falling fruit can cause serious injury to people, and damage vehicles parked under the trees.
Kigelia is also used in a number of skin care products. The most notable being African Earthworks Kigelia. The main aim of the African earthworks range of products is to alleviate the damage caused by the harsh African sun.
## Synonymy
Some synonyms are still accepted by a few horticulturists as distinct species, but botanical studies agree that the genus contains only one species (Joffe 2003, GRIN).
- Bignonia africana Lam. (basionym)
Tecoma africana (Lam.) G.Don
- Tecoma africana (Lam.) G.Don
- Crescentia pinnata Jacq.
Kigelia pinnata (Jacq.) DC.
- Kigelia pinnata (Jacq.) DC.
- Kigelia abyssinica A.Rich.
- Kigelia aethiopica Decne. | Kigelia
Kigelia is a genus of flowering plants in the family Bignoniaceae. The genus comprises only one species, Kigelia africana, which occurs throughout tropical Africa from Eritrea and Chad south to northern South Africa, and west to Senegal and Namibia.
The genus name comes from the Mozambican Bantu name, kigeli-keia, while the common name Sausage Tree refers to the long, sausage-like fruit. Its name in Afrikaans Worsboom also means Sausage Tree, and its Arabic name means "the father of kit bags" (Roodt 1992).
It is a tree growing up to 20 m tall. The bark is grey and smooth at first, peeling on older trees. It can be as thick as 6 mm on a 15-cm branch (Roodt 1992). The wood is pale brown or yellowish, undifferentiated and not prone to cracking (Roodt 1992).
The tree is evergreen where rainfall occurs throughout the year, but deciduous where there is a long dry season. The leaves are opposite or in whorls of three, 30–50 cm long, pinnate, with six to ten oval leaflets up to 20 cm long and 6 cm broad; the terminal leaflet can be either present or absent. The flowers (and later the fruit) hang down from branches on long flexible stems (2-6 metres long). Flowers are produced in panicles; they are bell-shaped (similar to those of the african tulip tree but darker and more waxy), orange to reddish or purplish green, and about 10 cm wide. Individual flowers do not hang down but are oriented horizontally. Some birds are attracted to these flowers and the strong stems of each flower make ideal footholds. Their scent is most notable at night indicating their reliance on pollination by bats, which visit them for pollen and nectar.
The fruit is a woody berry from 30–100 cm long and up to 18 cm broad; it weighs between 5–10 kg, and hang down on long, rope-like peduncles. The fruit pulp is fibrous and pulpy, and contains numerous seeds. It is eaten by several species of mammals, including Baboons, Bushpigs, Savannah Elephants, Giraffes, Hippopotami, monkeys, and porcupines. The seeds are dispersed in their dung. The seeds are also eaten by Brown Parrots and Brown-headed Parrots, and the foliage by elephants and Greater Kudu (Joffe 2003; del Hoyo et al. 1997). Introduced specimens in Australian parks are very popular with cockatoos.
# Cultivation and uses
In African herbal medicine, the fruit is believed to be a cure for a wide range of ailments, from rheumatism, snakebites, evil spirits, syphilis, and even tornadoes (Watkins 1975). An alcoholic beverage similar to beer is also made from it. The fresh fruit is poisonous and strongly purgative; fruit are prepared for consumption by drying, roasting or fermentation (Joffe 2003; McBurney 2004). In Botswana the timber is used for makoros, yokes and oars (Roodt 1992).
The tree is widely grown as an ornamental tree in tropical regions for its decorative flowers and unusual fruit. Planting sites should be selected carefully, as the falling fruit can cause serious injury to people, and damage vehicles parked under the trees.
Kigelia is also used in a number of skin care products. The most notable being African Earthworks Kigelia. The main aim of the African earthworks range of products is to alleviate the damage caused by the harsh African sun.
## Synonymy
Some synonyms are still accepted by a few horticulturists as distinct species, but botanical studies agree that the genus contains only one species (Joffe 2003, GRIN).
- Bignonia africana Lam. (basionym)
Tecoma africana (Lam.) G.Don
- Tecoma africana (Lam.) G.Don
- Crescentia pinnata Jacq.
Kigelia pinnata (Jacq.) DC.
- Kigelia pinnata (Jacq.) DC.
- Kigelia abyssinica A.Rich.
- Kigelia aethiopica Decne. | https://www.wikidoc.org/index.php/Kigelia | |
f5c8054f3ef1c239f5f4241f079f6b57044aadc5 | wikidoc | Kikayon | Kikayon
Kikayon (קיקיון) is the Hebrew name of a plant mentioned in the Biblical Book of Jonah.
# Origins
The first use of the term kikayon is in the biblical book of Jonah, Chapter 4:
# Classification
The word kikayon is only referenced in the book of Jonah and there is some question as to what kind of plant it is. Some hypotheses include a gourd and a castor oil plant.
# Entheogenic interpretation
The description may indicate an entheogenic mushroom such as fly agaric (Amanita muscaria). Mushrooms grow and wither very rapidly ("in a night"), were uncultivated in ancient times ("not labored over") due to the invisibility of mushroom spores to the naked eye, and in some cultures the Amanita muscaria mushroom is associated with–and named after– an umbrella or parasol because of its shape ("a shadow over his head"). Paradoxically, the red cap of Amanita muscaria was also associated with the sun due to its round shape and color. When the mushroom cap is dried its color changes from red to gold, like the sun rising in the sky. The "rising sun" mushroom cap beating on Jonah's head and causing him to become faint describes the effects of fly agaric intoxication. In ancient times worms, maggots, serpents and dragons all fitted into one category (the Old English "wyrm" could mean any of these creatures), symbolizing chthonic forces, to which the Amanita muscaria mushroom also belonged. The Sanskrit mushroom names ahichattra(ka) and sarpacchattra(ka) mean "snake parasol". | Kikayon
Kikayon (קיקיון) is the Hebrew name of a plant mentioned in the Biblical Book of Jonah.
# Origins
The first use of the term kikayon is in the biblical book of Jonah, Chapter 4:
# Classification
The word kikayon is only referenced in the book of Jonah and there is some question as to what kind of plant it is. Some hypotheses include a gourd and a castor oil plant.
# Entheogenic interpretation
The description may indicate an entheogenic mushroom such as fly agaric (Amanita muscaria). Mushrooms grow and wither very rapidly ("in a night"), were uncultivated in ancient times ("not labored over") due to the invisibility of mushroom spores to the naked eye, and in some cultures the Amanita muscaria mushroom is associated with–and named after– an umbrella or parasol because of its shape [1] ("a shadow over his head"). Paradoxically, the red cap of Amanita muscaria was also associated with the sun due to its round shape and color. When the mushroom cap is dried its color changes from red to gold, like the sun rising in the sky.[2] The "rising sun" mushroom cap beating on Jonah's head and causing him to become faint describes the effects of fly agaric intoxication. In ancient times worms, maggots, serpents and dragons all fitted into one category [1] (the Old English "wyrm" could mean any of these creatures), symbolizing chthonic forces, to which the Amanita muscaria mushroom also belonged. The Sanskrit mushroom names ahichattra(ka) and sarpacchattra(ka) mean "snake parasol". [2]
# External links
- A biological data from Purdue University | https://www.wikidoc.org/index.php/Kikayon | |
e3e71ae964c51034dfb9d6db9eb54d637d9d6cce | wikidoc | Kinetic | Kinetic
The kinetic energy of an object is the extra energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its current velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. Negative work of the same magnitude would be required to return the body to a state of rest from that velocity.
# Etymology
The adjective "kinetic" to the noun energy has its roots in the Greek word for "motion" (kinesis). The terms kinetic energy and work and their present scientific meanings date back to the mid 19th century. Early understandings of these ideas can be attributed to Gaspard-Gustave Coriolis who in 1829 published the paper titled Du Calcul de l'Effet des Machines outlining the mathematics of kinetic energy.
William Thomson, later Lord Kelvin, is given the credit for coining the term kinetic energy c. 1849.
# Introduction
There are various forms of energy : chemical energy, heat, electromagnetic radiation, potential energy (gravitational, electric, elastic, etc.), nuclear energy, rest energy. These can be categorized in two main classes: potential energy and kinetic energy.
Kinetic energy can be best understood by examples that demonstrate how it is transformed from other forms of energy and to the other forms. For example, a cyclist will use chemical energy that was provided by food to accelerate a bicycle to a chosen speed. This speed can be maintained without further work, except to overcome air-resistance and friction. The energy has been converted into the energy of motion, known as kinetic energy but the process is not completely efficient and heat is also produced within the cyclist.
The kinetic energy in the moving bicycle and the cyclist can be converted to other forms. For example, the cyclist could encounter a hill just high enough to coast up, so that the bicycle comes to a complete halt at the top. The kinetic energy has now largely been converted to gravitational potential energy that can be released by freewheeling down the other side of the hill. (Since the bicycle lost some of its energy to friction, it will never regain all of its speed without further pedaling. Note that the energy is not destroyed; it has only been converted to another form by friction.) Alternatively the cyclist could connect a dynamo to one of the wheels and also generate some electrical energy on the descent. The bicycle would be traveling more slowly at the bottom of the hill because some of the energy has been diverted into making electrical power. Another possibility would be for the cyclist to apply the brakes, in which case the kinetic energy would be dissipated through friction as heat energy.
Like any physical quantity which is a function of velocity, the kinetic energy of an object does not depend only on the inner nature of that object. It also depends on the relationship between that object and the observer (in physics an observer is formally defined by a particular class of coordinate system called an inertial reference frame). Physical quantities like this are said to be not invariant. The kinetic energy is co-located with the object and contributes to its gravitational field.
## Calculations
There are several different equations that may be used to calculate the kinetic energy of an object. In many cases they give almost the same answer to well within measurable accuracy. Where they differ, the choice of which to use is determined by the velocity of the body or its size. Thus, if the object is moving at a velocity much smaller than the speed of light, the Newtonian (classical) mechanics will be sufficiently accurate; but if the speed is comparable to the speed of light, relativity starts to make significant differences to the result and should be used. If the size of the object is sub-atomic, the quantum mechanical equation is most appropriate.
# Newtonian kinetic energy
## Kinetic energy of rigid bodies
In classical mechanics, the kinetic energy of a "point object" (a body so small that its size can be ignored), or a non rotating rigid body, is given by the equation E_k = \begin{matrix} \frac{1}{2} \end{matrix} mv^2 where m is the mass and v is the speed of the body.
For example - one would calculate the kinetic energy of an 80 kg mass traveling at 18 meters per second (40 mph) as
Note that the kinetic energy increases with the square of the speed. This means, for example, that an object traveling twice as fast will have four times as much kinetic energy. As a result of this, a car traveling twice as fast requires four times as much distance to stop (assuming a constant braking force. See mechanical work).
Thus, the kinetic energy can be calculated using the formula:
where:
For the translational kinetic energy of a body with constant mass m, whose center of mass is moving in a straight line with speed v, as seen above is equal to
where:
Thus kinetic energy is a relative measure and no object can be said to have a unique kinetic energy. A rocket engine could be seen to transfer its energy to the rocket ship or to the exhaust stream depending upon the chosen frame of reference. But the total energy of the system, i.e. kinetic energy, fuel chemical energy, heat energy etc, will be conserved regardless of the choice of measurement frame.
The kinetic energy of an object is related to its momentum by the equation:
## Derivation and definition
The work done accelerating a particle during the infinitesimal time interval dt is given by the dot product of force and displacement:
Applying the product rule we see that:
Therefore (assuming constant mass), the following can be seen:
Since this is a total differential (that is, it only depends on the final state, not how the particle got there), we can integrate it and call the result kinetic energy:
This equation states that the kinetic energy (Ek) is equal to the integral of the dot product of the velocity (v) of a body and the infinitesimal change of the body's momentum (p). It is assumed that the body starts with no kinetic energy when it is at rest (motionless).
## Kinetic energy of systems
For a single point, or a rigid body that is not rotating, the kinetic energy goes to zero when the body stops.
However, for systems containing multiple independently moving bodies, which may exert forces between themselves, and may (or may not) be rotating; this is no longer true.
This energy is called 'internal energy'.
The kinetic energy of the system at any instant in time is simply the sum of the kinetic energies of the masses- including the kinetic energy due to the rotations.
An example would be the solar system. In the center of mass frame of the solar system, the Sun is (almost) stationary, but the planets and planetoids are in motion about it. Thus even in a stationary center of mass frame, there is still kinetic energy present.
However, recalculating the energy from different frames would be tedious, but there is a trick. The kinetic energy of the system from a different inertial frame can be calculated simply from the sum of the kinetic energy in the center of mass frame and adding on the energy that the total mass of bodies in the center of mass frame would have if it were moving at the relative speed between the two frames.
This may be simply shown: let V be the relative speed of the frame k from the center of mass frame i :
However, let \int \frac{v_i^2 dm}{2} = E_i the kinetic energy in the center of mass frame, \int v_i dm would be simply the total momentum which is by definition zero in the center of mass frame, and let the total mass: \int dm = M . Substituting, we get:
The kinetic energy of a system thus depends on the inertial frame of reference and it is lowest with respect to the center of mass reference frame, i.e., in a frame of reference in which the center of mass is stationary. In any other frame of reference there is an additional kinetic energy corresponding to the total mass moving at the speed of the center of mass.
## Rotating bodies
If a rigid body is rotating about any line through the center of mass then it has rotational kinetic energy (E_r) which is simply the sum of the kinetic energies of its moving parts, and thus it is equal to:
where:
(In this equation the moment of inertia must be taken about an axis through the center of mass and the rotation measured by ω must be around that axis; more general equations exist for systems where the object is subject to wobble due to its eccentric shape).
## Rotation in systems
It sometimes is convenient to split the total kinetic energy of a body into the sum of the body's center-of-mass translational kinetic energy and the energy of rotation around the center of mass rotational energy:
where:
Thus the kinetic energy of a tennis ball in flight is the kinetic energy due to its rotation, plus the kinetic energy due to its translation.
# Relativistic kinetic energy of rigid bodies
In special relativity, we must change the expression for linear momentum. Integrating by parts, we get:
Remembering that \gamma = (1 - v^2/c^2)^{-1/2}\!, we get:
And thus:
The constant of integration is found by observing that \gamma = 1\! when \mathbf{v }= 0, so we get the usual formula:
If a body's speed is a significant fraction of the speed of light, it is necessary to use relativistic mechanics (the theory of relativity as expounded by Albert Einstein) to calculate its kinetic energy.
For a relativistic object the momentum p is equal to:
where m is the rest mass, v is the object's speed, and c is the speed of light in vacuum.
Thus the work expended accelerating an object from rest to a relativistic speed is:
The equation shows that the energy of an object approaches infinity as the velocity v approaches the speed of light c, thus it is impossible to accelerate an object across this boundary.
The mathematical by-product of this calculation is the mass-energy equivalence formula—the body at rest must have energy content equal to:
At a low speed (v<<c), the relativistic kinetic energy may be approximated well by the classical kinetic energy. This is done by binomial approximation. Indeed, taking Taylor expansion for square root and keeping first two terms we get:
So, the total energy E can be partitioned into the energy of the rest mass plus the traditional Newtonian kinetic energy at low speeds.
When objects move at a speed much slower than light (e.g. in everyday phenomena on Earth), the first two terms of the series predominate. The next term in the approximation is small for low speeds, and can be found by extending the expansion into a Taylor series by one more term:
For example, for a speed of 10 km/s the correction to the Newtonian kinetic energy is 0.07 J/kg (on a Newtonian kinetic energy of 50 MJ/kg) and for a speed of 100 km/s it is 710 J/kg (on a Newtonian kinetic energy of 5 GJ/kg), etc.
For higher speeds, the formula for the relativistic kinetic energy is derived by simply subtracting the rest mass energy from the total energy:
The relation between kinetic energy and momentum is more complicated in this case, and is given by the equation:
This can also be expanded as a Taylor series, the first term of which is the simple expression from Newtonian mechanics.
What this suggests is that the formulas for energy and momentum are not special and axiomatic, but rather concepts which emerge from the equation of mass with energy and the principles of relativity.
# Quantum mechanical kinetic energy of rigid bodies
In the realm of quantum mechanics, the expectation value of the electron kinetic energy, \langle\hat{T}\rangle, for a system of electrons described by the wavefunction \vert\psi\rangle is a sum of 1-electron operator expectation values:
where m_e is the mass of the electron and \nabla^2_i is the Laplacian operator acting upon the coordinates of the ith electron and the summation runs over all electrons. Notice that this is the quantized version of the non-relativistic expression for kinetic energy in terms of momentum:
The density functional formalism of quantum mechanics requires knowledge of the electron density only, i.e., it formally does not require knowledge of the wavefunction. Given an electron density \rho(\mathbf{r}), the exact N-electron kinetic energy functional is unknown; however, for the specific case of a 1-electron system, the kinetic energy can be written as
where T is known as the Von Weizsacker kinetic energy functional.
# Some examples
Spacecraft use chemical energy to take off and gain considerable kinetic energy to reach orbital velocity. This kinetic energy gained during launch will remain constant while in orbit because there is almost no friction. However it becomes apparent at re-entry when the kinetic energy is converted to heat.
Kinetic energy can be passed from one object to another. In the game of billiards, the player gives kinetic energy to the cue ball by striking it with the cue stick. If the cue ball collides with another ball, it will slow down dramatically and the ball it collided with will accelerate to a speed as the kinetic energy is passed on to it. Collisions in billiards are effectively elastic collisions, where kinetic energy is preserved.
Flywheels are being developed as a method of energy storage (see article flywheel energy storage). This illustrates that kinetic energy can also be rotational. Note the formula in the articles on flywheels for calculating rotational kinetic energy is different, though analogous. | Kinetic
The kinetic energy of an object is the extra energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its current velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. Negative work of the same magnitude would be required to return the body to a state of rest from that velocity.
# Etymology
The adjective "kinetic" to the noun energy has its roots in the Greek word for "motion" (kinesis). The terms kinetic energy and work and their present scientific meanings date back to the mid 19th century. Early understandings of these ideas can be attributed to Gaspard-Gustave Coriolis who in 1829 published the paper titled Du Calcul de l'Effet des Machines outlining the mathematics of kinetic energy.
William Thomson, later Lord Kelvin, is given the credit for coining the term kinetic energy c. 1849.[citation needed]
# Introduction
There are various forms of energy : chemical energy, heat, electromagnetic radiation, potential energy (gravitational, electric, elastic, etc.), nuclear energy, rest energy. These can be categorized in two main classes: potential energy and kinetic energy.
Kinetic energy can be best understood by examples that demonstrate how it is transformed from other forms of energy and to the other forms. For example, a cyclist will use chemical energy that was provided by food to accelerate a bicycle to a chosen speed. This speed can be maintained without further work, except to overcome air-resistance and friction. The energy has been converted into the energy of motion, known as kinetic energy but the process is not completely efficient and heat is also produced within the cyclist.
The kinetic energy in the moving bicycle and the cyclist can be converted to other forms. For example, the cyclist could encounter a hill just high enough to coast up, so that the bicycle comes to a complete halt at the top. The kinetic energy has now largely been converted to gravitational potential energy that can be released by freewheeling down the other side of the hill. (Since the bicycle lost some of its energy to friction, it will never regain all of its speed without further pedaling. Note that the energy is not destroyed; it has only been converted to another form by friction.) Alternatively the cyclist could connect a dynamo to one of the wheels and also generate some electrical energy on the descent. The bicycle would be traveling more slowly at the bottom of the hill because some of the energy has been diverted into making electrical power. Another possibility would be for the cyclist to apply the brakes, in which case the kinetic energy would be dissipated through friction as heat energy.
Like any physical quantity which is a function of velocity, the kinetic energy of an object does not depend only on the inner nature of that object. It also depends on the relationship between that object and the observer (in physics an observer is formally defined by a particular class of coordinate system called an inertial reference frame). Physical quantities like this are said to be not invariant. The kinetic energy is co-located with the object and contributes to its gravitational field.
## Calculations
There are several different equations that may be used to calculate the kinetic energy of an object. In many cases they give almost the same answer to well within measurable accuracy. Where they differ, the choice of which to use is determined by the velocity of the body or its size. Thus, if the object is moving at a velocity much smaller than the speed of light, the Newtonian (classical) mechanics will be sufficiently accurate; but if the speed is comparable to the speed of light, relativity starts to make significant differences to the result and should be used. If the size of the object is sub-atomic, the quantum mechanical equation is most appropriate.
# Newtonian kinetic energy
## Kinetic energy of rigid bodies
In classical mechanics, the kinetic energy of a "point object" (a body so small that its size can be ignored), or a non rotating rigid body, is given by the equation <math>E_k = \begin{matrix} \frac{1}{2} \end{matrix} mv^2 </math> where m is the mass and v is the speed of the body.
For example - one would calculate the kinetic energy of an 80 kg mass traveling at 18 meters per second (40 mph) as
Note that the kinetic energy increases with the square of the speed. This means, for example, that an object traveling twice as fast will have four times as much kinetic energy. As a result of this, a car traveling twice as fast requires four times as much distance to stop (assuming a constant braking force. See mechanical work).
Thus, the kinetic energy can be calculated using the formula:
where:
For the translational kinetic energy of a body with constant mass m, whose center of mass is moving in a straight line with speed v, as seen above is equal to
where:
Thus kinetic energy is a relative measure and no object can be said to have a unique kinetic energy. A rocket engine could be seen to transfer its energy to the rocket ship or to the exhaust stream depending upon the chosen frame of reference. But the total energy of the system, i.e. kinetic energy, fuel chemical energy, heat energy etc, will be conserved regardless of the choice of measurement frame.
The kinetic energy of an object is related to its momentum by the equation:
## Derivation and definition
The work done accelerating a particle during the infinitesimal time interval dt is given by the dot product of force and displacement:
Applying the product rule we see that:
Therefore (assuming constant mass), the following can be seen:
Since this is a total differential (that is, it only depends on the final state, not how the particle got there), we can integrate it and call the result kinetic energy:
This equation states that the kinetic energy (Ek) is equal to the integral of the dot product of the velocity (v) of a body and the infinitesimal change of the body's momentum (p). It is assumed that the body starts with no kinetic energy when it is at rest (motionless).
## Kinetic energy of systems
For a single point, or a rigid body that is not rotating, the kinetic energy goes to zero when the body stops.
However, for systems containing multiple independently moving bodies, which may exert forces between themselves, and may (or may not) be rotating; this is no longer true.
This energy is called 'internal energy'.
The kinetic energy of the system at any instant in time is simply the sum of the kinetic energies of the masses- including the kinetic energy due to the rotations.
An example would be the solar system. In the center of mass frame of the solar system, the Sun is (almost) stationary, but the planets and planetoids are in motion about it. Thus even in a stationary center of mass frame, there is still kinetic energy present.
However, recalculating the energy from different frames would be tedious, but there is a trick. The kinetic energy of the system from a different inertial frame can be calculated simply from the sum of the kinetic energy in the center of mass frame and adding on the energy that the total mass of bodies in the center of mass frame would have if it were moving at the relative speed between the two frames.
This may be simply shown: let V be the relative speed of the frame k from the center of mass frame i :
However, let <math> \int \frac{v_i^2 dm}{2} = E_i </math> the kinetic energy in the center of mass frame, <math> \int v_i dm </math> would be simply the total momentum which is by definition zero in the center of mass frame, and let the total mass: <math> \int dm = M </math>. Substituting, we get:[1]
The kinetic energy of a system thus depends on the inertial frame of reference and it is lowest with respect to the center of mass reference frame, i.e., in a frame of reference in which the center of mass is stationary. In any other frame of reference there is an additional kinetic energy corresponding to the total mass moving at the speed of the center of mass.
## Rotating bodies
If a rigid body is rotating about any line through the center of mass then it has rotational kinetic energy (<math>E_r</math>) which is simply the sum of the kinetic energies of its moving parts, and thus it is equal to:
where:
(In this equation the moment of inertia must be taken about an axis through the center of mass and the rotation measured by ω must be around that axis; more general equations exist for systems where the object is subject to wobble due to its eccentric shape).
## Rotation in systems
It sometimes is convenient to split the total kinetic energy of a body into the sum of the body's center-of-mass translational kinetic energy and the energy of rotation around the center of mass rotational energy:
where:
Thus the kinetic energy of a tennis ball in flight is the kinetic energy due to its rotation, plus the kinetic energy due to its translation.
# Relativistic kinetic energy of rigid bodies
In special relativity, we must change the expression for linear momentum. Integrating by parts, we get:
Remembering that <math>\gamma = (1 - v^2/c^2)^{-1/2}\!</math>, we get:
And thus:
The constant of integration is found by observing that <math>\gamma = 1\!</math> when <math>\mathbf{v }= 0</math>, so we get the usual formula:
If a body's speed is a significant fraction of the speed of light, it is necessary to use relativistic mechanics (the theory of relativity as expounded by Albert Einstein) to calculate its kinetic energy.
For a relativistic object the momentum p is equal to:
where m is the rest mass, v is the object's speed, and c is the speed of light in vacuum.
Thus the work expended accelerating an object from rest to a relativistic speed is:
The equation shows that the energy of an object approaches infinity as the velocity v approaches the speed of light c, thus it is impossible to accelerate an object across this boundary.
The mathematical by-product of this calculation is the mass-energy equivalence formula—the body at rest must have energy content equal to:
At a low speed (v<<c), the relativistic kinetic energy may be approximated well by the classical kinetic energy. This is done by binomial approximation. Indeed, taking Taylor expansion for square root and keeping first two terms we get:
So, the total energy E can be partitioned into the energy of the rest mass plus the traditional Newtonian kinetic energy at low speeds.
When objects move at a speed much slower than light (e.g. in everyday phenomena on Earth), the first two terms of the series predominate. The next term in the approximation is small for low speeds, and can be found by extending the expansion into a Taylor series by one more term:
For example, for a speed of 10 km/s the correction to the Newtonian kinetic energy is 0.07 J/kg (on a Newtonian kinetic energy of 50 MJ/kg) and for a speed of 100 km/s it is 710 J/kg (on a Newtonian kinetic energy of 5 GJ/kg), etc.
For higher speeds, the formula for the relativistic kinetic energy [2] is derived by simply subtracting the rest mass energy from the total energy:
The relation between kinetic energy and momentum is more complicated in this case, and is given by the equation:
This can also be expanded as a Taylor series, the first term of which is the simple expression from Newtonian mechanics.
What this suggests is that the formulas for energy and momentum are not special and axiomatic, but rather concepts which emerge from the equation of mass with energy and the principles of relativity.
# Quantum mechanical kinetic energy of rigid bodies
In the realm of quantum mechanics, the expectation value of the electron kinetic energy, <math>\langle\hat{T}\rangle</math>, for a system of electrons described by the wavefunction <math>\vert\psi\rangle</math> is a sum of 1-electron operator expectation values:
where <math>m_e</math> is the mass of the electron and <math>\nabla^2_i</math> is the Laplacian operator acting upon the coordinates of the ith electron and the summation runs over all electrons. Notice that this is the quantized version of the non-relativistic expression for kinetic energy in terms of momentum:
The density functional formalism of quantum mechanics requires knowledge of the electron density only, i.e., it formally does not require knowledge of the wavefunction. Given an electron density <math>\rho(\mathbf{r})</math>, the exact N-electron kinetic energy functional is unknown; however, for the specific case of a 1-electron system, the kinetic energy can be written as
where <math>T[\rho]</math> is known as the Von Weizsacker kinetic energy functional.
# Some examples
Spacecraft use chemical energy to take off and gain considerable kinetic energy to reach orbital velocity. This kinetic energy gained during launch will remain constant while in orbit because there is almost no friction. However it becomes apparent at re-entry when the kinetic energy is converted to heat.
Kinetic energy can be passed from one object to another. In the game of billiards, the player gives kinetic energy to the cue ball by striking it with the cue stick. If the cue ball collides with another ball, it will slow down dramatically and the ball it collided with will accelerate to a speed as the kinetic energy is passed on to it. Collisions in billiards are effectively elastic collisions, where kinetic energy is preserved.
Flywheels are being developed as a method of energy storage (see article flywheel energy storage). This illustrates that kinetic energy can also be rotational. Note the formula in the articles on flywheels for calculating rotational kinetic energy is different, though analogous. | https://www.wikidoc.org/index.php/Kinetic | |
3b98b6a9591da5c0eb3b02b0e26c53a47acd025c | wikidoc | Nitrone | Nitrone
A nitrone is the N-oxide of an imine and a functional group in organic chemistry. The general structure is R1R2C=NR3+O-.
A nitrone is 1,3-dipole in 1,3-dipolar cycloadditions. It reacts with alkenes to an isoxazolidine:
One example of this reaction type is the reaction of various Baylis-Hillman adducts with C-Phenyl-N-methylnitrone forming an isoxazolidine in which R1 is phenyl, R2 is hydrogen and R3 is a methyl group .
Nitrones react with terminal alkynes and a copper salt to beta-lactam. This reaction is also called the The Kinugasa reaction for example in this reaction: :
The first step in this reaction is a dipolar cycloaddition of the nitrone with the in situ generated copper(I) acetylide to a 5-membered ring structure which rearranges in the second step. | Nitrone
A nitrone is the N-oxide of an imine and a functional group in organic chemistry. The general structure is R1R2C=NR3+O-.
A nitrone is 1,3-dipole in 1,3-dipolar cycloadditions. It reacts with alkenes to an isoxazolidine:
One example of this reaction type is the reaction of various Baylis-Hillman adducts with C-Phenyl-N-methylnitrone forming an isoxazolidine in which R1 is phenyl, R2 is hydrogen and R3 is a methyl group [1].
Nitrones react with terminal alkynes and a copper salt to beta-lactam. This reaction is also called the The Kinugasa reaction [2] for example in this reaction: [3]:
The first step in this reaction is a dipolar cycloaddition of the nitrone with the in situ generated copper(I) acetylide to a 5-membered ring structure which rearranges in the second step. | https://www.wikidoc.org/index.php/Kinugasa_reaction | |
ad59f42f6b16b321a62ae4f05d84822b774c4282 | wikidoc | Patella | Patella
# Overview
The patella or kneecap is a thick, triangular bone which articulates with the femur and covers and protects the front of the knee joint. It is the largest sesamoid bone in the human body. It is attached to the tendon of the quadriceps femoris muscle, which contracts to straighten the leg. The vastus intermedialis muscle is attached to the base of patella. The vastus lateralis and vastus medialis are attached to lateral and medial borders of patella respectively.
The patella is stabilised by the insertion of vastus medialis and the prominence of the anterior femoral condyles, which prevent lateral dislocation during flexion. The retinacular fibres of the patella also stabilise it during exercise.
The primary functional role of the patella is knee extension. The patella increases the leverage that the tendon can exert on the femur by increasing the angle at which it acts.
The patella ossifies between the ages 2-6 years. In some people it may be absent congenitally or hypoplastic. In 2% of the population there is a bipartite patella, which is usually asymptomatic.
Regarding non-human animals, the patella is fully developed only in placental mammals; marsupials have only rudimentary, non-ossified patellae. | Patella
Template:Infobox Bone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
The patella or kneecap is a thick, triangular bone which articulates with the femur and covers and protects the front of the knee joint. It is the largest sesamoid bone in the human body. It is attached to the tendon of the quadriceps femoris muscle, which contracts to straighten the leg. The vastus intermedialis muscle is attached to the base of patella. The vastus lateralis and vastus medialis are attached to lateral and medial borders of patella respectively.
The patella is stabilised by the insertion of vastus medialis and the prominence of the anterior femoral condyles, which prevent lateral dislocation during flexion. The retinacular fibres of the patella also stabilise it during exercise.
The primary functional role of the patella is knee extension. The patella increases the leverage that the tendon can exert on the femur by increasing the angle at which it acts.
The patella ossifies between the ages 2-6 years. In some people it may be absent congenitally or hypoplastic. In 2% of the population there is a bipartite patella, which is usually asymptomatic.
Regarding non-human animals, the patella is fully developed only in placental mammals; marsupials have only rudimentary, non-ossified patellae.[1] | https://www.wikidoc.org/index.php/Knee_cap | |
5a1d33eb1b6842d4da29a4e27ed00a2a0958e814 | wikidoc | Kriging | Kriging
Kriging is a group of geostatistical techniques to interpolate the value of a random field (e.g. the elevation Z of the landscape as a function of the geographic location) at an unobserved location from observations of its value at nearby locations.
The theory behind interpolation and extrapolation by Kriging was developed by the French mathematician Georges Matheron based on the Master's thesis of Daniel Gerhardus Krige, the pioneering plotter of distance-weighted average gold grades at the Witwatersrand reef complex in South Africa. The English verb is to krige and the most common adjective is kriging.
# Kriging interpolation
Kriging belongs to the family of linear least squares estimation algorithms. As illustrated in Figure 1, the aim of kriging is to estimate the value of an unknown real function f at a point x^*, given the values of the function at some other points x_1,\ldots, x_n. A kriging estimator is said to be linear because the predicted value \hat f(x^*) is a linear combination that may be written as
The weights \lambda_i are solutions of a system of linear equations which is obtained by assuming that f is a sample-path of a random process F(x), and that the error of prediction
is to be minimized in some sense. For instance, the so-called simple kriging assumption is that the mean and the covariance of F(x) is known and then, the kriging predictor is the one that minimizes the variance of the prediction error.
From the geological point of view, the practice of kriging is based on assuming continued mineralization between measured values. Assuming prior knowledge encapsulates how minerals co-occur as a function of space. Then, given an ordered set of measured grades, interpolation by kriging predicts mineral concentrations at unobserved points.
# Applications of kriging
The application of kriging to problems in geology and mining as well as to hydrology started in the mid-60's and especially in the 70's with the work of Georges Matheron. The connection between kriging and Geostatistics is still prevailing today.
Kriging is e.g. used in
- Mining
- Hydrogeology
- Natural resources
- Environmental science
- Remote sensing
- Black box modelling in computer experiments
## Controversy in mineral exploration and mining
The question of whether spatial dependence may be assumed or ought to be verified by applying Fisher's F-test to the variance of a set of measured values and the first variance term of the ordered set prior to interpolation by kriging is of particular relevance in mineral exploration and mining. For example, Clark’s hypothetical uranium data in Practical Geostatistics do not display a significant degree of spatial dependence but the author reports a kriged estimate for some selected coordinates within this sample space anyway. The practice of kriging lends itself to abuse, particularly when applied to a model ore distribution based on the assumption that ore concentrations display a significant degree of spatial dependency in the sample space under examination. Spatial dependence between borehole grades was assumed at Bre-X's Busang property, Hecla's Grouse Creek mine and scores of others where gold grades turned out to be lower than predicted. A significant degree of spatial dependence is required to justify interpolation between measured values in ordered sets. Failing to pass a test for spatial dependence would indicate that a constant model cannot be distinguished from a kriging model without further information or knowledge.
# Mathematical details
## General equations of kriging
Kriging is a group of geostatistical techniques to interpolate the value Z(x_0) of a random field Z(x) (e.g. the elevation Z of the landscape as a function of the geographic location x) at an unobserved location x_0 from observations z_i=Z(x_i),\;i=1,\ldots,n of the random field at nearby locations x_1,\ldots,x_n. Kriging computes the best linear unbiased estimator \hat{Z}(x_0) of Z(x_0) based on a stochastic model of the spatial dependence quantified either by the variogram \gamma(x,y) or by expectation \mu(x)=E and the covariance function c(x,y) of the random field.
The kriging estimator is given by a linear combination
-f the observed values z_i=Z(x_i) with weights w_i(x_0),\;i=1,\ldots,n chosen such that the variance (also called kriging variance or kriging error):
- \mathrm{Var}\left(Z(x)\right)-2\sum_{i=1}^nw_i(x_0)c(x_i,x_0)
minimized subject to the unbiasedness condition:
\mathrm{E}=\sum_{i=1}^n w_i(x_0)\mu(x_i) - \mu(x_0) =0
Depending on the stochastic properties of the random field different types of kriging apply. For the different types of kriging the unbiasedness condition is rewritten into different linear constraints for the weights w_i.
The kriging variance must not be confused with the variance
\mathrm{Var}\left(\hat{Z}(x_0)\right)=\mathrm{Var}\left(\sum_{i=1}^n w_iZ(x_i)\right)=\sum_{i=1}^n\sum_{j=1}^n w_i w_j c(x_i,x_j)
-f the kriging predictor \hat{Z}(x_0) itself.
## The types of kriging
Classical types of kriging are
- Simple kriging assuming a known constant trend: \mu(x)=0.
- Ordinary kriging assuming an unknown constant trend: \mu(x)=\mu.
- Universal kriging assuming a general linear trend model \mu(x)=\sum_{k=0}^p \beta_k f(x).
- IRFk-kriging assuming \mu(x) to be an unknown polynomial in x.
- Indicator kriging using indicator functions instead of the process itself, in order to estimate transition probabilities.
- Multiple-indicator kriging is a version of indicatior kriging working with a family of indicators. However, MIK has fallen out of favour as an interpolation technique in recent years. This is due to some inherent difficulties related to operation and model validation. Conditional simulation is fast becoming the accepted replacement technique in this case.
- Disjunctive kriging is a nonlinear generalisation of kriging.
- Lognormal kriging interpolates positive data by means of logarithms.
## Simple kriging
Simple kriging is the most simple kind of kriging. It assumes the expectation of the random field to be known, and relies on a covariance function. However, in most applications neither the expectation nor the covariance are known beforehand.
### Simple kriging assumptions
The practical assumptions for the application of simple kriging are:
- wide sense stationarity of the field.
- The expectation is zero everywhere: \mu(x)=0.
- Known covariance function c(x,y)=\mathrm{Cov}(Z(x),Z(y))
### Simple kriging equation
The kriging weights of simple kriging have no unbiasedness condition
and are given by the simple kriging equation system:
\begin{pmatrix}c(x_1,x_1) & \cdots & c(x_1,x_n) \\
\vdots & \ddots & \vdots \\
c(x_n,x_1) & \cdots & c(x_n,x_n)
\end{pmatrix}^{-1}
\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0) \end{pmatrix}
### Simple kriging interpolation
The interpolation by simple kriging is given by:
\begin{pmatrix}c(x_1,x_1) & \cdots & c(x_1,x_n) \\
\vdots & \ddots & \vdots \\
c(x_n,x_1) & \cdots & c(x_n,x_n)
\end{pmatrix}^{-1}
\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0)\end{pmatrix}
### Simple kriging error
The kriging error is given by:
\underbrace{\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0)\end{pmatrix}'
\begin{pmatrix}
c(x_1,x_1) & \cdots & c(x_1,x_n) \\
\vdots & \ddots & \vdots \\
c(x_n,x_1) & \cdots & c(x_n,x_n)
\end{pmatrix}^{-1}
\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0) \end{pmatrix}}_{\mathrm{Var}(\hat{Z}(x))}
which leads to the generalised least squares version of the Gauss-Markov theorem (Chiles & Delfiner 1999, p. 159):
## Ordinary kriging
Ordinary kriging is the most commonly used type of kriging. It assumes a constant but unknown mean.
### Typical ordinary kriging assumptions
The typical assumptions for the practical application of ordinary kriging are:
- Intrinsic stationarity or wide sense stationarity of the field
- enough observations to estimate the variogram.
The mathematical condition for applicability of ordinary kriging are:
- The mean E=\mu is unknown but constant
- The variogram \gamma(x,y)=E of Z(x) is known.
### Ordinary kriging equation
The kriging weights of ordinary kriging fulfill the unbiasedness condition
and are given by the ordinary kriging equation system:
\begin{pmatrix}\gamma(x_1,x_1) & \cdots & \gamma(x_1,x_n) &1 \\
\vdots & \ddots & \vdots & \vdots \\
\gamma(x_n,x_1) & \cdots & \gamma(x_n,x_n) & 1 \\
1 &\cdots& 1 & 0
\end{pmatrix}^{-1}
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}
the additional parameter \lambda is a Lagrange multiplier used in the minization of the kriging error \sigma_k^2(x) to honor the unbiasedness condition.
### Ordinary kriging interpolation
The interpolation by ordinary kriging is given by:
\begin{pmatrix}\gamma(x_1,x_1) & \cdots & \gamma(x_1,x_n) &1 \\
\vdots & \ddots & \vdots & \vdots \\
\gamma(x_n,x_1) & \cdots & \gamma(x_n,x_n) & 1 \\
1 &\cdots& 1 & 0
\end{pmatrix}^{-1}
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}
### Ordinary kriging error
The kriging error is given by:
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}'
\begin{pmatrix}
\gamma(x_1,x_1) & \cdots & \gamma(x_1,x_n) &1 \\
\vdots & \ddots & \vdots & \vdots \\
\gamma(x_n,x_1) & \cdots & \gamma(x_n,x_n) & 1 \\
1 &\cdots& 1 & 0
\end{pmatrix}^{-1}
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}
## Properties of kriging
(Cressie 1993, Chiles&Delfiner 1999, Wackernagel 1995)
- The kriging estimation is unbiased: E=E
- The kriging estimation honors the actually observed value: \hat{Z}(x_i)=Z(x_i)
- The kriging estimation \hat{Z}(x) is the best linear unbiased estimator of Z(x) if the assumptions hold. However (e.g. Cressie 1993):
As with any method: If the assumptions do not hold, kriging might be bad.
There might be better nonlinear and/or biased methods.
No properties are guaranteed, when the wrong variogram is used. However typically still a 'good' interpolation is achieved.
Best is not necessarily good: e.g. In case of no spatial dependence the kriging interpolation is only as good as the arithmetic mean.
- As with any method: If the assumptions do not hold, kriging might be bad.
- There might be better nonlinear and/or biased methods.
- No properties are guaranteed, when the wrong variogram is used. However typically still a 'good' interpolation is achieved.
- Best is not necessarily good: e.g. In case of no spatial dependence the kriging interpolation is only as good as the arithmetic mean.
- Kriging provides \sigma_k^2 as a measure of precision. However this measure relies on the correctness of the variogram.
# Related terms and techniques
## Kriging terms
A series of related terms were also named after Krige, including kriged estimate, kriged estimator, kriging variance, kriging covariance, zero kriging variance, unity kriging covariance, kriging matrix, kriging method, kriging model, kriging plan, kriging process, kriging system, block kriging, co-kriging, disjunctive kriging, linear kriging, ordinary kriging, point kriging, random kriging, regular grid kriging, simple kriging and universal kriging.
## Related methods
Kriging is mathematically closely related to regression analysis. Both theories derive a best linear unbiased estimator, based on assumptions on covariances, make use of Gauss-Markov theorem to prove independence of the estimate and error, and make use of very similar formulae. They are nevertheless useful in different frameworks: Kriging is made for interpolation of a single realisation of a random field, while regression models are based on multiple observations of a multivariate dataset.
In the statistical community the same technique is also known as Gaussian process regression, Kolmogorov Wiener prediction, or best linear unbiased prediction.
The kriging interpolation may also be seen as a spline in a reproducing kernel Hilbert space, with reproducing kernel given by the covariance function. The difference with the classical kriging approach is provided by the interpretation: while the spline is motivated by a minimum norm interpolation based on a Hilbert space structure, kriging is motivated by an expected squared prediction error based on a stochastic model.
Kriging with polynomial trend surfaces is mathematically identical to generalized least squares polynomial curve fitting.
Kriging can also be understood as a form of bayesian inference. Kriging starts with a prior distribution over functions. This prior takes the form of a Gaussian process: N samples from a function will be normally distributed, where the covariance between any two samples is the covariance function (or kernel) of the Gaussian process evaluated at the spatial location of two points. A set of values is then observed, each value associated with a spatial location. Now, a new value can be predicted at any new spatial location, by combining the Gaussian prior with a Gaussian likelihood function for each of the observed values. The resulting posterior distribution is also Gaussian, with a mean and covariance that can be simply computed from the observed values, their variance, and the kernel matrix derived from the prior.
# History
The theory of Kriging was developed by the French mathematician Georges Matheron based on the Master's thesis of Daniel Gerhardus Krige, the pioneering plotter of distance-weighted average gold grades at the Witwatersrand reef complex. The English verb is to krige and the most common adjective is kriging. The method was called krigeage for the first time in Matheron's 1960 Krigeage d’un Panneau Rectangulaire par sa Périphérie. Matheron, in this Note Géostatistique No 28, derives k*, his 'estimateur' and a precursor to the kriged estimate or kriged estimator. In classical statistics, Matheron’s k- is the length-weighted average grade of each of his panneaux in his set. What Matheron failed to derive was var(k*), the variance of his estimateur. On the contrary, he computed the length-weighted average grade of each panneau but did not compute the variance of its central value. In time, he replaced length-weighted average grades for three-dimensional sample spaces such as Matheronian blocks of ore with more abundant distance-weighted average grades for zero-dimensional sample spaces such as Matheronian points.
A central doctrine of geostatistics is that spatial dependence need not be verified but may be assumed to exist between two or more Matheronian points, determined in samples selected at positions with different coordinates. This doctrine of assumed causality is the quintessence of Matheron's new science of geostatistics. The question remains whether assumed causality makes sense in any other scientific discipline. The more so because central values such as distance- and length-weighted averages metamorphosed so smoothly into either kriged estimates or kriged estimators.
Matheron’s 1967 Kriging, or Polynomial Interpolation Procedures? A contribution to polemics in mathematical geology, praises the precise probabilistic background of kriging and finds least-squares polynomial interpolation wanting. In fact, Matheron preferred kriging because it gives infinite sets of kriged estimates or kriged estimators in finite three-dimensional sample spaces. Infinite sets of points on polynomials were rather restrictive for Matheron’s new science of geostatistics. | Kriging
Kriging is a group of geostatistical techniques to interpolate the value of a random field (e.g. the elevation Z of the landscape as a function of the geographic location) at an unobserved location from observations of its value at nearby locations.
The theory behind interpolation and extrapolation by Kriging was developed by the French mathematician Georges Matheron based on the Master's thesis of Daniel Gerhardus Krige, the pioneering plotter of distance-weighted average gold grades at the Witwatersrand reef complex in South Africa. The English verb is to krige and the most common adjective is kriging.
# Kriging interpolation
Kriging belongs to the family of linear least squares estimation algorithms. As illustrated in Figure 1, the aim of kriging is to estimate the value of an unknown real function <math>f</math> at a point <math>x^*</math>, given the values of the function at some other points <math>x_1,\ldots, x_n</math>. A kriging estimator is said to be linear because the predicted value <math>\hat f(x^*)</math> is a linear combination that may be written as
The weights <math>\lambda_i</math> are solutions of a system of linear equations which is obtained by assuming that <math>f</math> is a sample-path of a random process <math>F(x)</math>, and that the error of prediction
is to be minimized in some sense. For instance, the so-called simple kriging assumption is that the mean and the covariance of <math>F(x)</math> is known and then, the kriging predictor is the one that minimizes the variance of the prediction error.
From the geological point of view, the practice of kriging is based on assuming continued mineralization between measured values. Assuming prior knowledge encapsulates how minerals co-occur as a function of space. Then, given an ordered set of measured grades, interpolation by kriging predicts mineral concentrations at unobserved points.
# Applications of kriging
The application of kriging to problems in geology and mining as well as to hydrology started in the mid-60's and especially in the 70's with the work of Georges Matheron. The connection between kriging and Geostatistics is still prevailing today.
Kriging is e.g. used in
- Mining[1][2]
- Hydrogeology[3][4][5]
- Natural resources[6][7]
- Environmental science[8]
- Remote sensing[9]
- Black box modelling in computer experiments[10]
## Controversy in mineral exploration and mining
The question of whether spatial dependence may be assumed or ought to be verified by applying Fisher's F-test to the variance of a set of measured values and the first variance term of the ordered set prior to interpolation by kriging is of particular relevance in mineral exploration and mining. For example, Clark’s hypothetical uranium data in Practical Geostatistics do not display a significant degree of spatial dependence but the author reports a kriged estimate for some selected coordinates within this sample space anyway. The practice of kriging lends itself to abuse, particularly when applied to a model ore distribution based on the assumption that ore concentrations display a significant degree of spatial dependency in the sample space under examination. Spatial dependence between borehole grades was assumed at Bre-X's Busang property, Hecla's Grouse Creek mine and scores of others where gold grades turned out to be lower than predicted. A significant degree of spatial dependence is required to justify interpolation between measured values in ordered sets. Failing to pass a test for spatial dependence would indicate that a constant model cannot be distinguished from a kriging model without further information or knowledge.
# Mathematical details
## General equations of kriging
Kriging is a group of geostatistical techniques to interpolate the value <math>Z(x_0)</math> of a random field <math>Z(x)</math> (e.g. the elevation <math>Z</math> of the landscape as a function of the geographic location <math>x</math>) at an unobserved location <math>x_0</math> from observations <math>z_i=Z(x_i),\;i=1,\ldots,n</math> of the random field at nearby locations <math>x_1,\ldots,x_n</math>. Kriging computes the best linear unbiased estimator <math>\hat{Z}(x_0)</math> of <math>Z(x_0)</math> based on a stochastic model of the spatial dependence quantified either by the variogram <math>\gamma(x,y)</math> or by expectation <math>\mu(x)=E[Z(x)]</math> and the covariance function <math>c(x,y)</math> of the random field.
The kriging estimator is given by a linear combination
of the observed values <math>z_i=Z(x_i)</math> with weights <math>w_i(x_0),\;i=1,\ldots,n</math> chosen such that the variance (also called kriging variance or kriging error):
+ \mathrm{Var}\left(Z(x)\right)-2\sum_{i=1}^nw_i(x_0)c(x_i,x_0)</math>
minimized subject to the unbiasedness condition:
\mathrm{E}[\hat{Z}(x)-Z(x)]=\sum_{i=1}^n w_i(x_0)\mu(x_i) - \mu(x_0) =0
</math>
Depending on the stochastic properties of the random field different types of kriging apply. For the different types of kriging the unbiasedness condition is rewritten into different linear constraints for the weights <math>w_i</math>.
The kriging variance must not be confused with the variance
\mathrm{Var}\left(\hat{Z}(x_0)\right)=\mathrm{Var}\left(\sum_{i=1}^n w_iZ(x_i)\right)=\sum_{i=1}^n\sum_{j=1}^n w_i w_j c(x_i,x_j)
</math>
of the kriging predictor <math>\hat{Z}(x_0)</math> itself.
## The types of kriging
Classical types of kriging are
- Simple kriging assuming a known constant trend: <math>\mu(x)=0</math>.
- Ordinary kriging assuming an unknown constant trend: <math>\mu(x)=\mu</math>.
- Universal kriging assuming a general linear trend model <math>\mu(x)=\sum_{k=0}^p \beta_k f(x)</math>.
- IRFk-kriging assuming <math>\mu(x)</math> to be an unknown polynomial in <math>x</math>.
- Indicator kriging using indicator functions instead of the process itself, in order to estimate transition probabilities.
- Multiple-indicator kriging is a version of indicatior kriging working with a family of indicators. However, MIK has fallen out of favour as an interpolation technique in recent years. This is due to some inherent difficulties related to operation and model validation. Conditional simulation is fast becoming the accepted replacement technique in this case.
- Disjunctive kriging is a nonlinear generalisation of kriging.
- Lognormal kriging interpolates positive data by means of logarithms.
## Simple kriging
Simple kriging is the most simple kind of kriging. It assumes the expectation of the random field to be known, and relies on a covariance function. However, in most applications neither the expectation nor the covariance are known beforehand.
### Simple kriging assumptions
The practical assumptions for the application of simple kriging are:
- wide sense stationarity of the field.
- The expectation is zero everywhere: <math>\mu(x)=0</math>.
- Known covariance function <math>c(x,y)=\mathrm{Cov}(Z(x),Z(y))</math>
### Simple kriging equation
The kriging weights of simple kriging have no unbiasedness condition
and are given by the simple kriging equation system:
\begin{pmatrix}c(x_1,x_1) & \cdots & c(x_1,x_n) \\
\vdots & \ddots & \vdots \\
c(x_n,x_1) & \cdots & c(x_n,x_n)
\end{pmatrix}^{-1}
\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0) \end{pmatrix}
</math>
### Simple kriging interpolation
The interpolation by simple kriging is given by:
\begin{pmatrix}c(x_1,x_1) & \cdots & c(x_1,x_n) \\
\vdots & \ddots & \vdots \\
c(x_n,x_1) & \cdots & c(x_n,x_n)
\end{pmatrix}^{-1}
\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0)\end{pmatrix}
</math>
### Simple kriging error
The kriging error is given by:
\underbrace{\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0)\end{pmatrix}'
\begin{pmatrix}
c(x_1,x_1) & \cdots & c(x_1,x_n) \\
\vdots & \ddots & \vdots \\
c(x_n,x_1) & \cdots & c(x_n,x_n)
\end{pmatrix}^{-1}
\begin{pmatrix}c(x_1,x_0) \\ \vdots \\ c(x_n,x_0) \end{pmatrix}}_{\mathrm{Var}(\hat{Z}(x))}
</math>
which leads to the generalised least squares version of the Gauss-Markov theorem (Chiles & Delfiner 1999, p. 159):
## Ordinary kriging
Ordinary kriging is the most commonly used type of kriging. It assumes a constant but unknown mean.
### Typical ordinary kriging assumptions
The typical assumptions for the practical application of ordinary kriging are:
- Intrinsic stationarity or wide sense stationarity of the field
- enough observations to estimate the variogram.
The mathematical condition for applicability of ordinary kriging are:
- The mean <math>E[Z(x)]=\mu</math> is unknown but constant
- The variogram <math>\gamma(x,y)=E[(Z(x)-Z(y))^2]</math> of <math>Z(x)</math> is known.
### Ordinary kriging equation
The kriging weights of ordinary kriging fulfill the unbiasedness condition
and are given by the ordinary kriging equation system:
\begin{pmatrix}\gamma(x_1,x_1) & \cdots & \gamma(x_1,x_n) &1 \\
\vdots & \ddots & \vdots & \vdots \\
\gamma(x_n,x_1) & \cdots & \gamma(x_n,x_n) & 1 \\
1 &\cdots& 1 & 0
\end{pmatrix}^{-1}
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}
</math>
the additional parameter <math>\lambda</math> is a Lagrange multiplier used in the minization of the kriging error <math>\sigma_k^2(x)</math> to honor the unbiasedness condition.
### Ordinary kriging interpolation
The interpolation by ordinary kriging is given by:
\begin{pmatrix}\gamma(x_1,x_1) & \cdots & \gamma(x_1,x_n) &1 \\
\vdots & \ddots & \vdots & \vdots \\
\gamma(x_n,x_1) & \cdots & \gamma(x_n,x_n) & 1 \\
1 &\cdots& 1 & 0
\end{pmatrix}^{-1}
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}
</math>
### Ordinary kriging error
The kriging error is given by:
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}'
\begin{pmatrix}
\gamma(x_1,x_1) & \cdots & \gamma(x_1,x_n) &1 \\
\vdots & \ddots & \vdots & \vdots \\
\gamma(x_n,x_1) & \cdots & \gamma(x_n,x_n) & 1 \\
1 &\cdots& 1 & 0
\end{pmatrix}^{-1}
\begin{pmatrix}\gamma(x_1,x^*) \\ \vdots \\ \gamma(x_n,x^*) \\ 1\end{pmatrix}
</math>
## Properties of kriging
(Cressie 1993, Chiles&Delfiner 1999, Wackernagel 1995)
- The kriging estimation is unbiased: <math>E[\hat{Z}(x_i)]=E[Z(x_i)]</math>
- The kriging estimation honors the actually observed value: <math>\hat{Z}(x_i)=Z(x_i)</math>
- The kriging estimation <math>\hat{Z}(x)</math> is the best linear unbiased estimator of <math>Z(x)</math> if the assumptions hold. However (e.g. Cressie 1993):
As with any method: If the assumptions do not hold, kriging might be bad.
There might be better nonlinear and/or biased methods.
No properties are guaranteed, when the wrong variogram is used. However typically still a 'good' interpolation is achieved.
Best is not necessarily good: e.g. In case of no spatial dependence the kriging interpolation is only as good as the arithmetic mean.
- As with any method: If the assumptions do not hold, kriging might be bad.
- There might be better nonlinear and/or biased methods.
- No properties are guaranteed, when the wrong variogram is used. However typically still a 'good' interpolation is achieved.
- Best is not necessarily good: e.g. In case of no spatial dependence the kriging interpolation is only as good as the arithmetic mean.
- Kriging provides <math>\sigma_k^2</math> as a measure of precision. However this measure relies on the correctness of the variogram.
# Related terms and techniques
## Kriging terms
A series of related terms were also named after Krige, including kriged estimate, kriged estimator, kriging variance, kriging covariance, zero kriging variance, unity kriging covariance, kriging matrix, kriging method, kriging model, kriging plan, kriging process, kriging system, block kriging, co-kriging, disjunctive kriging, linear kriging, ordinary kriging, point kriging, random kriging, regular grid kriging, simple kriging and universal kriging.
## Related methods
Kriging is mathematically closely related to regression analysis. Both theories derive a best linear unbiased estimator, based on assumptions on covariances, make use of Gauss-Markov theorem to prove independence of the estimate and error, and make use of very similar formulae. They are nevertheless useful in different frameworks: Kriging is made for interpolation of a single realisation of a random field, while regression models are based on multiple observations of a multivariate dataset.
In the statistical community the same technique is also known as Gaussian process regression, Kolmogorov Wiener prediction, or best linear unbiased prediction.
The kriging interpolation may also be seen as a spline in a reproducing kernel Hilbert space, with reproducing kernel given by the covariance function.[11] The difference with the classical kriging approach is provided by the interpretation: while the spline is motivated by a minimum norm interpolation based on a Hilbert space structure, kriging is motivated by an expected squared prediction error based on a stochastic model.
Kriging with polynomial trend surfaces is mathematically identical to generalized least squares polynomial curve fitting.
Kriging can also be understood as a form of bayesian inference.[12] Kriging starts with a prior distribution over functions. This prior takes the form of a Gaussian process: <math>N</math> samples from a function will be normally distributed, where the covariance between any two samples is the covariance function (or kernel) of the Gaussian process evaluated at the spatial location of two points. A set of values is then observed, each value associated with a spatial location. Now, a new value can be predicted at any new spatial location, by combining the Gaussian prior with a Gaussian likelihood function for each of the observed values. The resulting posterior distribution is also Gaussian, with a mean and covariance that can be simply computed from the observed values, their variance, and the kernel matrix derived from the prior.
# History
The theory of Kriging was developed by the French mathematician Georges Matheron based on the Master's thesis of Daniel Gerhardus Krige, the pioneering plotter of distance-weighted average gold grades at the Witwatersrand reef complex. The English verb is to krige and the most common adjective is kriging. The method was called krigeage for the first time in Matheron's 1960 Krigeage d’un Panneau Rectangulaire par sa Périphérie. Matheron, in this Note Géostatistique No 28, derives k*, his 'estimateur' and a precursor to the kriged estimate or kriged estimator. In classical statistics, Matheron’s k* is the length-weighted average grade of each of his panneaux in his set. What Matheron failed to derive was var(k*), the variance of his estimateur. On the contrary, he computed the length-weighted average grade of each panneau but did not compute the variance of its central value. In time, he replaced length-weighted average grades for three-dimensional sample spaces such as Matheronian blocks of ore with more abundant distance-weighted average grades for zero-dimensional sample spaces such as Matheronian points.
A central doctrine of geostatistics is that spatial dependence need not be verified but may be assumed to exist between two or more Matheronian points, determined in samples selected at positions with different coordinates. This doctrine of assumed causality is the quintessence of Matheron's new science of geostatistics. The question remains whether assumed causality makes sense in any other scientific discipline. The more so because central values such as distance- and length-weighted averages metamorphosed so smoothly into either kriged estimates or kriged estimators.
Matheron’s 1967 Kriging, or Polynomial Interpolation Procedures? A contribution to polemics in mathematical geology, praises the precise probabilistic background of kriging and finds least-squares polynomial interpolation wanting. In fact, Matheron preferred kriging because it gives infinite sets of kriged estimates or kriged estimators in finite three-dimensional sample spaces. Infinite sets of points on polynomials were rather restrictive for Matheron’s new science of geostatistics. | https://www.wikidoc.org/index.php/Kriging | |
36da4a516f3e7e9e666619ebc8b86675c347927e | wikidoc | Lindane | Lindane
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# Black Box Warning
# Overview
Lindane is an ectoparasiticide and ovicide. that is FDA approved for the treatment of Scabies (infestations of Sarcoptes scabei ) only in patients who cannot tolerate other approved therapies or have failed treatment with other approved therapies. There is a Black Box Warning for this drug as shown here. Common adverse reactions include pruritus, post-treatment, dizziness, insomnia, anxiety.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
- Apply a thin layer of Lindane Lotion over all skin from the neck down. One ounce is sufficient for an average adult. Do not prescribe more than 2 ounces for larger adults. Apply only once. Wash off in 8 to 12 hours. Do not retreat.
- Patients should be provided specific information on use of product.
- Patients should be instructed on proper use of Lindane Lotion, especially the amount to apply, how long to leave on and the need to avoid retreatment. Patients should be informed that itching occurs after the successful killing of scabies (mites) and continued itching is not necessarily an indication for retreatment with Lindane Lotion.
- A Lindane Lotion Medication Guide must be given to the patient each time Lindane Lotion is dispensed, as required by law. The Lindane Lotion Medication Guide is an important part of the risk management program for the patient.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Lindane in adult patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Lindane in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
- Apply a thin layer of Lindane Lotion over all skin from the neck down. One ounce is sufficient for an average adult. Do not prescribe more than 2 ounces for larger adults. Apply only once. Wash off in 8 to 12 hours. Do not retreat.
- Patients should be provided specific information on use of product.
- Patients should be instructed on proper use of Lindane Lotion, especially the amount to apply, how long to leave on and the need to avoid retreatment. Patients should be informed that itching occurs after the successful killing of scabies (mites) and continued itching is not necessarily an indication for retreatment with Lindane Lotion.
- A Lindane Lotion Medication Guide must be given to the patient each time Lindane Lotion is dispensed, as required by law. The Lindane Lotion Medication Guide is an important part of the risk management program for the patient.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Lindane in pediatric patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Lindane in pediatric patients.
# Contraindications
- Lindane Lotion is contraindicated for premature infants because their skin may be more permeable than that of full term infants and their liver enzymes may not be sufficiently developed to metabolize Lindane. Lindane Lotion is also contraindicated for patients with crusted (Norwegian) scabies and other skin conditions (e.g., atopic dermatitis, psoriasis) that may increase systemic absorption of the drug. Lindane Lotion is contraindicated for patients with known uncontrolled seizure disorders and for individuals with a known sensitivity to the product or any of its components.
# Warnings
- Seizures and deaths have been reported following Lindane Lotion's use with repeat or prolonged application, but also in rare cases following a single application reportedly used according to directions. It is not known how soon after application of a single dose of Lindane Lotion that a second dose of Lindane Lotion can be safely applied.
- There have been cases of adverse events reported for Lindane Lotion and Lindane Shampoo in which a serious outcome (hospitalization, disability or death) has occurred.4 In approximately 20% of the total reported cases, Lindane Lotion and Shampoo were reported to have been used according to the labeled directions. Of these cases, thirteen deaths were reported, many cases which were remote from the time of actual Lindane use. Lindane toxicity, verified by autopsy was the cause of one infant's death, was the cause of death reported for an adult who ingested it orally in a successful suicide. The direct causes of death for the other cases were attributed to reasons other than Lindane. Most of these adverse events occurred with Lindane Lotion.
- Infants, children, the elderly, and individuals with other skin conditions and those who weigh < 110 lbs (50 kg) may be at greater risk of serious neurotoxicity. Animal studies have shown increased susceptibility to neurologic adverse events in younger animals. Children have a larger body surface area to volume ratio that may result in a proportionately larger systemic exposure.
- Careful consideration should be given before prescribing Lindane Lotion to patients with conditions that may increase the risk of seizure, such as HIV infection, history of head trauma or a prior seizure, CNS tumor, the presence of severe hepatic cirrhosis, excessive use of alcohol, abrupt withdrawal from alcohol or sedatives, as well as concomitant use of medications known to lower seizure threshold.
- Patients should be instructed on proper use of Lindane Lotion, especially the amount to apply, how long to leave the lotion on, and the need to avoid retreatment. Patients should be informed that itching may occur, and even worsen, after the successful killing of scabies. Repeat treatment is usually not necessary.
- A Lindane Lotion Medication Guide must be given to the patient each time Lindane Lotion is dispensed, as required by law.
# Adverse Reactions
## Clinical Trials Experience
- Lindane Lotion has been reported to cause central nervous system stimulation ranging from dizziness to seizures. Although seizures were almost always associated with ingestion or misuse of the product (to include repeat treatment), seizures and deaths have been reported when Lindane Lotion was used according to directions. Irritant dermatitis from contact with this product has also been reported
## Postmarketing Experience
- The following adverse reactions reflect additional postmarketing experience of Lindane Lotion. These events include alopecia, dermatitis, headache, pain, paresthesia, pruritus and urticaria. The relationship of some of these events to Lindane therapy is unknown.
# Drug Interactions
Oils may enhance absorption of Lindane, therefore, patients or caregivers applying Lindane Lotion should be warned about simultaneous use of creams, ointments, or oils. In addition, there are many drugs that may lower the seizure threshold, and Lindane Lotion should be prescribed with caution in patients taking these medications. Drugs that may lower the seizure threshold include, but are not limited to the following:
- Antipsychotics
- Antidepressants
- Theophylline
- Cyclosporine
- Mycophenolate mofetil
- Tacrolimus capsules
- Penicillins, imipenem, quinolone antibiotics
- Chloroquine sulfate, pyrimethamine
- Isoniazid
- Meperidine
- Radiographic contrast agents
- Centrally active anticholinesterases
- Methocarbamol
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA): C
- All pregnancies have a risk of birth defect, loss, or other adverse event regardless of drug exposure. Predictions of fetal risk from drug exposure rely heavily on animal data. However, animal studies may fail to predict effects in humans or may overstate such risks. Even if human data are available, the data may not be sufficient to determine whether there is an increased risk to the fetus, and individual reports of adverse outcomes in pregnancy in association with a drug may not reflect a causal relationship.
- Lindane Lotion should be given to pregnant women only if clearly needed. There are no adequate and well-controlled studies of Lindane Lotion in pregnant women. There are no known maternal or fetal health risks if the scabies is not treated. Lindane is lipophilic and may accumulate in the placenta. There has been a single case report of a stillborn infant following multiple maternal exposures to lindane during pregnancy. The relationship of the maternal exposures to the fetal outcome is unknown.
- Animal data suggest that lindane exposure of the fetus may increase the likelihood of neurologic developmental abnormalities, based on findings at systemic exposures close to that expected in humans when Lindane Lotion is used to treat scabies. The immature central nervous system (as in the fetus) may have increased susceptibility to the effects of the drug.
Pregnancy Category (AUS):
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Lindane in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Lindane during labor and delivery.
### Nursing Mothers
- Lindane is lipophilic and is present in human breast milk, but exact quantities are not known. There may be a risk of toxicity if lindane is ingested from breast milk, or from skin absorption from mother to baby in the course of breast-feeding when Lindane Lotion is applied topically to the chest area. Nursing mothers who require treatment with Lindane Lotion should be advised of the potential risks and be counseled to avoid large areas of skin-to-skin contact with the infant while Lindane Lotion is applied, as well as to interrupt breast-feeding, with expression and discarding of milk, for at least 24 hours following use.
### Pediatric Use
- Animal data demonstrated increased risk of adverse events in the young across species. Pediatric patients have a higher surface to volume ratio and may be at risk of greater systemic exposure when Lindane Lotion is applied to the body. Infants and children may be at an even higher risk due to immaturity of organ systems such as skin and liver. Lindane Lotion should be used with extreme caution in patients who weigh less than approximately 110 lbs (50 kg) and especially in infants. Lindane Lotion is indicated only for the treatment of scabies; patients with lice should use Lindane Shampoo according to the labeled instructions.
### Geriatic Use
- There have been no studies of Lindane Lotion in the elderly. There are four postmarketing reports of deaths in elderly patients who were treated for scabies with Lindane Lotion. Two patients died within 24 hours of Lindane Lotion application, and the third patient died 41 days after application of Lindane Lotion, having suffered a seizure on the day of death. A fourth patient died of an unreported cause of death on the same day that Lindane Lotion treatment for scabies was administered.
### Gender
There is no FDA guidance on the use of Lindane with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Lindane with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Lindane in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Lindane in patients with hepatic impairment.
### Females of Reproductive Potential and Males
- Although no studies have been conducted with Lindane Lotion, numerous long-term feeding studies have been conducted in mice and rats to evaluate the carcinogenic potential of the technical grade of hexachlorocyclohexane as well as the alpha, beta, gamma (lindane) and delta isomers. Both oral and topical applications have been evaluated. Increased incidences of neoplasms were not clearly related to administration of lindane. The results of mutagenicity tests in bacteria do not indicate that lindane is mutagenic. Lindane did not cause sister chromatid exchange in an in vivo assay. The number of spermatids in the testes of rats 2 weeks after oral administration of a single dose of 30 mg/kg body weight (12 times the estimated human exposure for scabies on a body surface area comparison and assuming 50% rat oral bioavailability and 10% human bioavailability) was significantly reduced compared to the control rats.
### Immunocompromised Patients
There is no FDA guidance one the use of Lindane in patients who are immunocompromised.
# Administration and Monitoring
### Administration
There is limited information regarding Lindane Administration in the drug label.
### Monitoring
There is limited information regarding Lindane Monitoring in the drug label.
# IV Compatibility
There is limited information regarding the compatibility of Lindane and IV administrations.
# Overdosage
Contact the closest Poison Control Center in the event of suspected overdosage with Lindane Lotion.
- If accidental ingestion occurs, prompt gastric lavage should be instituted. However, since oils enhance absorption, saline cathartics for intestinal evacuation should be given rather than oil laxatives. If central nervous system (CNS) manifestations occur, they may be antagonized by the administration of pentobarbital, phenobarbital, or diazepam.
# Pharmacology
## Mechanism of Action
There is limited information regarding Lindane Mechanism of Action in the drug label.
## Structure
- Lindane is the gamma isomer of 1,2,3,4,5,6-hexachlorocyclohexane having the following structural formula:
## Pharmacodynamics
There is limited information regarding Lindane Pharmacodynamics in the drug label.
## Pharmacokinetics
- Lindane Lotion, USP 1%, is an ectoparasiticide and ovicide effective against Sarcoptes scabiei (scabies). Lindane exerts its parasiticidal action by being directly absorbed into the parasites and their ova. Feldmann and Maibach1 reported approximately 10% systemic absorption of a lindane acetone solution when applied to the forearm of human subjects and left in place for 24 hours. This vehicle was different from the approved product and the percutaneous penetration of lindane is dependent on the vehicle. Therefore, the clinical significance of these observations is unknown. Dale, et al2 reported a blood level of 290 ng/mL associated with convulsions following the accidental ingestion of a lindane-containing product. Ginsburg 3 found the greatest peak blood level of 64 ng/mL, 6 hours after total body application of Lindane Lotion in 1 of 8 non-scabietic pediatric patients. The half-life in blood was determined to be approximately 18 hours.
- Data available in the literature suggest that lindane has a rapid distribution phase followed by a longer β-elimination phase.1, 2, 3
## Nonclinical Toxicology
There is limited information regarding Lindane Nonclinical Toxicology in the drug label.
# Clinical Studies
There is limited information regarding Lindane Clinical Studies in the drug label.
# How Supplied
- Lindane Lotion, USP 1% is supplied in patient-size 2 fl oz (60 mL) bottles.
## Storage
- Store at 20° to 25°C (68° to 77°F)
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
There is limited information regarding Lindane Patient Counseling Information in the drug label.
# Precautions with Alcohol
- Alcohol-Lindane interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- Kwell
- Thionex
# Look-Alike Drug Names
There is limited information regarding Lindane Look-Alike Drug Names in the drug label.
# Drug Shortage Status
# Price | Lindane
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alberto Plate [2]
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
# Black Box Warning
# Overview
Lindane is an ectoparasiticide and ovicide. that is FDA approved for the treatment of Scabies (infestations of Sarcoptes scabei ) only in patients who cannot tolerate other approved therapies or have failed treatment with other approved therapies. There is a Black Box Warning for this drug as shown here. Common adverse reactions include pruritus, post-treatment, dizziness, insomnia, anxiety.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
- Apply a thin layer of Lindane Lotion over all skin from the neck down. One ounce is sufficient for an average adult. Do not prescribe more than 2 ounces for larger adults. Apply only once. Wash off in 8 to 12 hours. Do not retreat.
- Patients should be provided specific information on use of product.
- Patients should be instructed on proper use of Lindane Lotion, especially the amount to apply, how long to leave on and the need to avoid retreatment. Patients should be informed that itching occurs after the successful killing of scabies (mites) and continued itching is not necessarily an indication for retreatment with Lindane Lotion.
- A Lindane Lotion Medication Guide must be given to the patient each time Lindane Lotion is dispensed, as required by law. The Lindane Lotion Medication Guide is an important part of the risk management program for the patient.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Lindane in adult patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Lindane in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
- Apply a thin layer of Lindane Lotion over all skin from the neck down. One ounce is sufficient for an average adult. Do not prescribe more than 2 ounces for larger adults. Apply only once. Wash off in 8 to 12 hours. Do not retreat.
- Patients should be provided specific information on use of product.
- Patients should be instructed on proper use of Lindane Lotion, especially the amount to apply, how long to leave on and the need to avoid retreatment. Patients should be informed that itching occurs after the successful killing of scabies (mites) and continued itching is not necessarily an indication for retreatment with Lindane Lotion.
- A Lindane Lotion Medication Guide must be given to the patient each time Lindane Lotion is dispensed, as required by law. The Lindane Lotion Medication Guide is an important part of the risk management program for the patient.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Lindane in pediatric patients.
### Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Lindane in pediatric patients.
# Contraindications
- Lindane Lotion is contraindicated for premature infants because their skin may be more permeable than that of full term infants and their liver enzymes may not be sufficiently developed to metabolize Lindane. Lindane Lotion is also contraindicated for patients with crusted (Norwegian) scabies and other skin conditions (e.g., atopic dermatitis, psoriasis) that may increase systemic absorption of the drug. Lindane Lotion is contraindicated for patients with known uncontrolled seizure disorders and for individuals with a known sensitivity to the product or any of its components.
# Warnings
- Seizures and deaths have been reported following Lindane Lotion's use with repeat or prolonged application, but also in rare cases following a single application reportedly used according to directions. It is not known how soon after application of a single dose of Lindane Lotion that a second dose of Lindane Lotion can be safely applied.
- There have been cases of adverse events reported for Lindane Lotion and Lindane Shampoo in which a serious outcome (hospitalization, disability or death) has occurred.4 In approximately 20% of the total reported cases, Lindane Lotion and Shampoo were reported to have been used according to the labeled directions. Of these cases, thirteen deaths were reported, many cases which were remote from the time of actual Lindane use. Lindane toxicity, verified by autopsy was the cause of one infant's death, was the cause of death reported for an adult who ingested it orally in a successful suicide. The direct causes of death for the other cases were attributed to reasons other than Lindane. Most of these adverse events occurred with Lindane Lotion.
- Infants, children, the elderly, and individuals with other skin conditions and those who weigh < 110 lbs (50 kg) may be at greater risk of serious neurotoxicity. Animal studies have shown increased susceptibility to neurologic adverse events in younger animals. Children have a larger body surface area to volume ratio that may result in a proportionately larger systemic exposure.
- Careful consideration should be given before prescribing Lindane Lotion to patients with conditions that may increase the risk of seizure, such as HIV infection, history of head trauma or a prior seizure, CNS tumor, the presence of severe hepatic cirrhosis, excessive use of alcohol, abrupt withdrawal from alcohol or sedatives, as well as concomitant use of medications known to lower seizure threshold.
- Patients should be instructed on proper use of Lindane Lotion, especially the amount to apply, how long to leave the lotion on, and the need to avoid retreatment. Patients should be informed that itching may occur, and even worsen, after the successful killing of scabies. Repeat treatment is usually not necessary.
- A Lindane Lotion Medication Guide must be given to the patient each time Lindane Lotion is dispensed, as required by law.
# Adverse Reactions
## Clinical Trials Experience
- Lindane Lotion has been reported to cause central nervous system stimulation ranging from dizziness to seizures. Although seizures were almost always associated with ingestion or misuse of the product (to include repeat treatment), seizures and deaths have been reported when Lindane Lotion was used according to directions. Irritant dermatitis from contact with this product has also been reported
## Postmarketing Experience
- The following adverse reactions reflect additional postmarketing experience of Lindane Lotion. These events include alopecia, dermatitis, headache, pain, paresthesia, pruritus and urticaria. The relationship of some of these events to Lindane therapy is unknown.
# Drug Interactions
Oils may enhance absorption of Lindane, therefore, patients or caregivers applying Lindane Lotion should be warned about simultaneous use of creams, ointments, or oils. In addition, there are many drugs that may lower the seizure threshold, and Lindane Lotion should be prescribed with caution in patients taking these medications. Drugs that may lower the seizure threshold include, but are not limited to the following:
- Antipsychotics
- Antidepressants
- Theophylline
- Cyclosporine
- Mycophenolate mofetil
- Tacrolimus capsules
- Penicillins, imipenem, quinolone antibiotics
- Chloroquine sulfate, pyrimethamine
- Isoniazid
- Meperidine
- Radiographic contrast agents
- Centrally active anticholinesterases
- Methocarbamol
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA): C
- All pregnancies have a risk of birth defect, loss, or other adverse event regardless of drug exposure. Predictions of fetal risk from drug exposure rely heavily on animal data. However, animal studies may fail to predict effects in humans or may overstate such risks. Even if human data are available, the data may not be sufficient to determine whether there is an increased risk to the fetus, and individual reports of adverse outcomes in pregnancy in association with a drug may not reflect a causal relationship.
- Lindane Lotion should be given to pregnant women only if clearly needed. There are no adequate and well-controlled studies of Lindane Lotion in pregnant women. There are no known maternal or fetal health risks if the scabies is not treated. Lindane is lipophilic and may accumulate in the placenta. There has been a single case report of a stillborn infant following multiple maternal exposures to lindane during pregnancy. The relationship of the maternal exposures to the fetal outcome is unknown.
- Animal data suggest that lindane exposure of the fetus may increase the likelihood of neurologic developmental abnormalities, based on findings at systemic exposures close to that expected in humans when Lindane Lotion is used to treat scabies. The immature central nervous system (as in the fetus) may have increased susceptibility to the effects of the drug.
Pregnancy Category (AUS):
There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Lindane in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Lindane during labor and delivery.
### Nursing Mothers
- Lindane is lipophilic and is present in human breast milk, but exact quantities are not known. There may be a risk of toxicity if lindane is ingested from breast milk, or from skin absorption from mother to baby in the course of breast-feeding when Lindane Lotion is applied topically to the chest area. Nursing mothers who require treatment with Lindane Lotion should be advised of the potential risks and be counseled to avoid large areas of skin-to-skin contact with the infant while Lindane Lotion is applied, as well as to interrupt breast-feeding, with expression and discarding of milk, for at least 24 hours following use.
### Pediatric Use
- Animal data demonstrated increased risk of adverse events in the young across species. Pediatric patients have a higher surface to volume ratio and may be at risk of greater systemic exposure when Lindane Lotion is applied to the body. Infants and children may be at an even higher risk due to immaturity of organ systems such as skin and liver. Lindane Lotion should be used with extreme caution in patients who weigh less than approximately 110 lbs (50 kg) and especially in infants. Lindane Lotion is indicated only for the treatment of scabies; patients with lice should use Lindane Shampoo according to the labeled instructions.
### Geriatic Use
- There have been no studies of Lindane Lotion in the elderly. There are four postmarketing reports of deaths in elderly patients who were treated for scabies with Lindane Lotion. Two patients died within 24 hours of Lindane Lotion application, and the third patient died 41 days after application of Lindane Lotion, having suffered a seizure on the day of death. A fourth patient died of an unreported cause of death on the same day that Lindane Lotion treatment for scabies was administered.
### Gender
There is no FDA guidance on the use of Lindane with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Lindane with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Lindane in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Lindane in patients with hepatic impairment.
### Females of Reproductive Potential and Males
- Although no studies have been conducted with Lindane Lotion, numerous long-term feeding studies have been conducted in mice and rats to evaluate the carcinogenic potential of the technical grade of hexachlorocyclohexane as well as the alpha, beta, gamma (lindane) and delta isomers. Both oral and topical applications have been evaluated. Increased incidences of neoplasms were not clearly related to administration of lindane. The results of mutagenicity tests in bacteria do not indicate that lindane is mutagenic. Lindane did not cause sister chromatid exchange in an in vivo assay. The number of spermatids in the testes of rats 2 weeks after oral administration of a single dose of 30 mg/kg body weight (12 times the estimated human exposure for scabies on a body surface area comparison and assuming 50% rat oral bioavailability and 10% human bioavailability) was significantly reduced compared to the control rats.
### Immunocompromised Patients
There is no FDA guidance one the use of Lindane in patients who are immunocompromised.
# Administration and Monitoring
### Administration
There is limited information regarding Lindane Administration in the drug label.
### Monitoring
There is limited information regarding Lindane Monitoring in the drug label.
# IV Compatibility
There is limited information regarding the compatibility of Lindane and IV administrations.
# Overdosage
Contact the closest Poison Control Center in the event of suspected overdosage with Lindane Lotion.
- If accidental ingestion occurs, prompt gastric lavage should be instituted. However, since oils enhance absorption, saline cathartics for intestinal evacuation should be given rather than oil laxatives. If central nervous system (CNS) manifestations occur, they may be antagonized by the administration of pentobarbital, phenobarbital, or diazepam.
# Pharmacology
## Mechanism of Action
There is limited information regarding Lindane Mechanism of Action in the drug label.
## Structure
- Lindane is the gamma isomer of 1,2,3,4,5,6-hexachlorocyclohexane having the following structural formula:
## Pharmacodynamics
There is limited information regarding Lindane Pharmacodynamics in the drug label.
## Pharmacokinetics
- Lindane Lotion, USP 1%, is an ectoparasiticide and ovicide effective against Sarcoptes scabiei (scabies). Lindane exerts its parasiticidal action by being directly absorbed into the parasites and their ova. Feldmann and Maibach1 reported approximately 10% systemic absorption of a lindane acetone solution when applied to the forearm of human subjects and left in place for 24 hours. This vehicle was different from the approved product and the percutaneous penetration of lindane is dependent on the vehicle. Therefore, the clinical significance of these observations is unknown. Dale, et al2 reported a blood level of 290 ng/mL associated with convulsions following the accidental ingestion of a lindane-containing product. Ginsburg 3 found the greatest peak blood level of 64 ng/mL, 6 hours after total body application of Lindane Lotion in 1 of 8 non-scabietic pediatric patients. The half-life in blood was determined to be approximately 18 hours.
- Data available in the literature suggest that lindane has a rapid distribution phase followed by a longer β-elimination phase.1, 2, 3
## Nonclinical Toxicology
There is limited information regarding Lindane Nonclinical Toxicology in the drug label.
# Clinical Studies
There is limited information regarding Lindane Clinical Studies in the drug label.
# How Supplied
- Lindane Lotion, USP 1% is supplied in patient-size 2 fl oz (60 mL) bottles.
## Storage
- Store at 20° to 25°C (68° to 77°F)
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
There is limited information regarding Lindane Patient Counseling Information in the drug label.
# Precautions with Alcohol
- Alcohol-Lindane interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- Kwell
- Thionex
# Look-Alike Drug Names
There is limited information regarding Lindane Look-Alike Drug Names in the drug label.
# Drug Shortage Status
# Price | https://www.wikidoc.org/index.php/Kwell | |
fa6bae76dce853f7fd311438fc46da57153d866b | wikidoc | Proline | Proline
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.
Proline (abbreviated as Pro or P) is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that humans can synthesize it. It is the unique proteogenic amino acid where the α-amino group is secondary.
# Biosynthesis
Proline is biosynthetically derived from the amino acid L-glutamate and its immediate precursor is the imino acid (S)-Δ1-pyrroline-5-carboxylate (P5C). Enzymes involved in a typical biosynthesis include:
- glutamate kinase (ATP-dependent)
- glutamate dehydrogenase (requires NADH or NADPH)
- pyrroline-5-carboxylate reductase (requires NADH or NADPH)
# Structural properties
The distinctive cyclic structure of proline's side chain locks its \phi backbone dihedral angle at approximately -75°, giving proline an exceptional conformational rigidity compared to other amino acids. Hence, proline loses less conformational entropy upon folding, which may account for its higher prevalence in the proteins of thermophilic organisms. Proline acts as a structural disruptor in the middle of regular secondary structure elements such as alpha helices and beta sheets; however, proline is commonly found as the first residue of an alpha helix and also in the edge strands of beta sheets. Proline is also commonly found in turns, which may account for the curious fact that proline is usually solvent-exposed, despite having a completely aliphatic side chain. Because proline lacks a hydrogen on the amide group, it cannot act as a hydrogen bond donor, only as a hydrogen bond acceptor.
Multiple prolines and/or hydroxyprolines in a row can create a polyproline helix, the predominant secondary structure in collagen. The hydroxylation of proline by prolyl hydroxylase (or other additions of electron-withdrawing substituents such as fluorine) increases the conformational stability of collagen significantly. Hence, the hydroxylation of proline is a critical biochemical process for maintaining the connective tissue of higher organisms. Severe diseases such as scurvy can result from defects in this hydroxylation, e.g., mutations in the enzyme prolyl hydroxylase or lack of the necessary ascorbate (vitamin C) cofactor.
Sequences of proline and 2-aminoisobutyric acid (Aib) also form a helical turn structure.
In 2006, scientists at ASU discovered that solutions of TiO2 illuminated with ultraviolet radiation can serve as an extremely cost-effective and accurate protein cleavage catalyst. The TiO2 catalyst preferentially and rapidly cleaves protein at sites where proline is present, while taking much longer to degrade the protein from its endpoints.
# Cis-trans isomerization
Peptide bonds to proline and other N-substituted amino acids (such as sarcosine) are able to populate both the cis and trans isomers. Most peptide bonds prefer overwhelmingly to adopt the trans isomer (typically 99.9% under unstrained conditions), chiefly because the amide hydrogen (trans isomer) offers less steric repulsion to the preceding \mathrm{C}^{\alpha} atom than does the following \mathrm{C}^{\alpha} atom (cis isomer). By contrast, the cis and trans isomers of the X-Pro peptide bond both experience steric clashes with the neighboring subtitution and are nearly equally energetically disfavorable. Hence, the fraction of X-Pro peptide bonds in the cis isomer under unstrained conditions ranges from 10-40%; the fraction depends slightly on the preceding amino acid X, with aromatic residues favoring the cis isomer slightly.
From a kinetic standpoint, Cis-trans proline isomerization is a very slow process that can impede the progress of protein folding by trapping one or more prolines crucial for folding in the nonnative isomer, especially when the native protein requires the cis isomer. This is because proline residues are exclusively synthesized in the ribosome as the trans isomer form. All organisms possess prolyl isomerase enzymes to catalyze this isomerization, and some bacteria have specialized prolyl isomerases associated with the ribosome. However, not all prolines are essential for folding, and protein folding may proceed at a normal rate despite having non-native conformers of many X-Pro peptide bonds.
# Usage
Proline and its derivatives are often used as asymmetric catalysts in organic reactions. The CBS reduction and proline catalysed aldol condensation are prominent examples.
L-proline is an ingredient in energy drinks such as "Sobe power fruit punch". Proline has a sweet flavor with a distinct aftertaste. | Proline
Template:NatOrganicBox
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
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 [2] 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.
Proline (abbreviated as Pro or P) is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that humans can synthesize it. It is the unique proteogenic amino acid where the α-amino group is secondary.
# Biosynthesis
Proline is biosynthetically derived from the amino acid L-glutamate and its immediate precursor is the imino acid (S)-Δ1-pyrroline-5-carboxylate (P5C). Enzymes involved in a typical biosynthesis include:[1]
- glutamate kinase (ATP-dependent)
- glutamate dehydrogenase (requires NADH or NADPH)
- pyrroline-5-carboxylate reductase (requires NADH or NADPH)
# Structural properties
The distinctive cyclic structure of proline's side chain locks its <math>\phi</math> backbone dihedral angle at approximately -75°, giving proline an exceptional conformational rigidity compared to other amino acids. Hence, proline loses less conformational entropy upon folding, which may account for its higher prevalence in the proteins of thermophilic organisms. Proline acts as a structural disruptor in the middle of regular secondary structure elements such as alpha helices and beta sheets; however, proline is commonly found as the first residue of an alpha helix and also in the edge strands of beta sheets. Proline is also commonly found in turns, which may account for the curious fact that proline is usually solvent-exposed, despite having a completely aliphatic side chain. Because proline lacks a hydrogen on the amide group, it cannot act as a hydrogen bond donor, only as a hydrogen bond acceptor.
Multiple prolines and/or hydroxyprolines in a row can create a polyproline helix, the predominant secondary structure in collagen. The hydroxylation of proline by prolyl hydroxylase (or other additions of electron-withdrawing substituents such as fluorine) increases the conformational stability of collagen significantly. Hence, the hydroxylation of proline is a critical biochemical process for maintaining the connective tissue of higher organisms. Severe diseases such as scurvy can result from defects in this hydroxylation, e.g., mutations in the enzyme prolyl hydroxylase or lack of the necessary ascorbate (vitamin C) cofactor.
Sequences of proline and 2-aminoisobutyric acid (Aib) also form a helical turn structure[citation needed].
In 2006, scientists at ASU discovered that solutions of TiO2 illuminated with ultraviolet radiation can serve as an extremely cost-effective and accurate protein cleavage catalyst. The TiO2 catalyst preferentially and rapidly cleaves protein at sites where proline is present, while taking much longer to degrade the protein from its endpoints.[2]
# Cis-trans isomerization
Peptide bonds to proline and other N-substituted amino acids (such as sarcosine) are able to populate both the cis and trans isomers. Most peptide bonds prefer overwhelmingly to adopt the trans isomer (typically 99.9% under unstrained conditions), chiefly because the amide hydrogen (trans isomer) offers less steric repulsion to the preceding <math>\mathrm{C}^{\alpha}</math> atom than does the following <math>\mathrm{C}^{\alpha}</math> atom (cis isomer). By contrast, the cis and trans isomers of the X-Pro peptide bond both experience steric clashes with the neighboring subtitution and are nearly equally energetically disfavorable. Hence, the fraction of X-Pro peptide bonds in the cis isomer under unstrained conditions ranges from 10-40%; the fraction depends slightly on the preceding amino acid X, with aromatic residues favoring the cis isomer slightly.
From a kinetic standpoint, Cis-trans proline isomerization is a very slow process that can impede the progress of protein folding by trapping one or more prolines crucial for folding in the nonnative isomer, especially when the native protein requires the cis isomer. This is because proline residues are exclusively synthesized in the ribosome as the trans isomer form. All organisms possess prolyl isomerase enzymes to catalyze this isomerization, and some bacteria have specialized prolyl isomerases associated with the ribosome. However, not all prolines are essential for folding, and protein folding may proceed at a normal rate despite having non-native conformers of many X-Pro peptide bonds.
# Usage
Proline and its derivatives are often used as asymmetric catalysts in organic reactions. The CBS reduction and proline catalysed aldol condensation are prominent examples.
L-proline is an ingredient in energy drinks such as "Sobe power fruit punch". [3] Proline has a sweet flavor with a distinct aftertaste. | https://www.wikidoc.org/index.php/L-proline | |
00400ac4b26e2efeefc5d1c8b2a901dfb99764e8 | wikidoc | LAPTM4B | LAPTM4B
Lysosomal-associated transmembrane protein 4B is a protein that in humans is encoded by the LAPTM4B gene.
LAPTM4B protein contains a lysosome localization motif and localizes on late endosomes and lysosomes.
# Clinical significance
Increased expression of LAPTM4B has been found in breast, liver, lung, ovarian, uterine, gastric cancers. Elevated LAPTM4B level contributes to chemotherapy resistance in breast cancer. It was found that overexpression of LAPTM4B causes anthracyclines (doxorubicin, daunorubicin, and epirubicin) resistance by retaining drug in the cytoplasm and decreasing nuclear localization of drug and drug induced DNA damage.
In 2011, the same group reported that LAPTM4B also promotes autophagy, a cell survival mechanism mediated by lysosomes. LAPTM4B promotes autophagy and renders tumor cells resistant to metabolic and genotoxic stress and results in more rapid tumor growth.
Based on these findings, LAPTM4B can be utilized to be a therapeutic target to prevent chemotherapy resistance or a marker to identify the patients who will not benefit from anthracyclines. | LAPTM4B
Lysosomal-associated transmembrane protein 4B is a protein that in humans is encoded by the LAPTM4B gene.[1]
LAPTM4B protein contains a lysosome localization motif and localizes on late endosomes and lysosomes.
# Clinical significance
Increased expression of LAPTM4B has been found in breast, liver, lung, ovarian, uterine, gastric cancers. Elevated LAPTM4B level contributes to chemotherapy resistance in breast cancer. It was found that overexpression of LAPTM4B causes anthracyclines (doxorubicin, daunorubicin, and epirubicin) resistance by retaining drug in the cytoplasm and decreasing nuclear localization of drug and drug induced DNA damage.[2]
In 2011, the same group reported that LAPTM4B also promotes autophagy, a cell survival mechanism mediated by lysosomes. LAPTM4B promotes autophagy and renders tumor cells resistant to metabolic and genotoxic stress and results in more rapid tumor growth.[3]
Based on these findings, LAPTM4B can be utilized to be a therapeutic target to prevent chemotherapy resistance or a marker to identify the patients who will not benefit from anthracyclines.[2] | https://www.wikidoc.org/index.php/LAPTM4B | |
458dbebca19613177d50350f27cfd5b5cc4ca2a7 | wikidoc | LGALS13 | LGALS13
Placental protein 13 (PP13) is a protein that in humans is encoded by the LGALS13 gene.
# Structure and function
# Function
It is composed of two identical subunits which are held together by disulfide bonds. The monomer of this protein has structural similarity to several members of the beta-galactoside-binding S-type lectin family, but it could not bind beta-galactoside. This is because the ligand binding site is lack of key residue for binding beta-galactoside. It is a galectin-like protein. The ligand of this protein is still unknown.
# Clinical significance
PP13 levels that are low in the first trimester of pregnancy confers a higher risk for developing pre-eclampsia later in pregnancy. | LGALS13
Placental protein 13 (PP13) is a protein that in humans is encoded by the LGALS13 gene.[1][2]
# Structure and function
# Function
It is composed of two identical subunits which are held together by disulfide bonds. The monomer of this protein has structural similarity to several members of the beta-galactoside-binding S-type lectin family, but it could not bind beta-galactoside. This is because the ligand binding site is lack of key residue for binding beta-galactoside. [3]It is a galectin-like protein. The ligand of this protein is still unknown.
# Clinical significance
PP13 levels that are low in the first trimester of pregnancy confers a higher risk for developing pre-eclampsia later in pregnancy.[4] | https://www.wikidoc.org/index.php/LGALS13 | |
b2026c948170bec24493967b4c16c908c88c7517 | wikidoc | LRRC16A | LRRC16A
Leucine rich repeat containing 16A is a protein that in humans is encoded by the LRRC16A gene. The gene is also known as LRRC16, CARMIL, CARMIL1 or CARMIL1a.
# Model organisms
Model organisms have been used in the study of LRRC16A function. A conditional knockout mouse line, called Lrrc16atm1a(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 — at the Wellcome Trust Sanger Institute.
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Twenty two tests were carried out on mutant mice but no significant abnormalities were observed. | LRRC16A
Leucine rich repeat containing 16A is a protein that in humans is encoded by the LRRC16A gene.[1] The gene is also known as LRRC16, CARMIL, CARMIL1 or CARMIL1a.[1]
# Model organisms
Model organisms have been used in the study of LRRC16A function. A conditional knockout mouse line, called Lrrc16atm1a(KOMP)Wtsi[6][7] 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 — at the Wellcome Trust Sanger Institute.[8][9][10]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[4][11] Twenty two tests were carried out on mutant mice but no significant abnormalities were observed.[4] | https://www.wikidoc.org/index.php/LRRC16A | |
a27e48aa88f2255e106c9e016cd1fbbcfc6db5ea | wikidoc | LYPLAL1 | LYPLAL1
Lysophospholipase-like 1 is a protein in humans that is encoded by the LYPLAL1 gene.
The protein is a α/β-hydrolase of uncharacterized metabolic function. Genome-wide association studies in humans have linked the gene to fat distribution and waist-to-hip ratio. The protein's enzymatic function is unclear. LYPLAL1 was reported to act as a triglyceride lipase in adipose tissue and another study suggested that the protein may play a role in the depalmitoylation of calcium-activated potassium channels. However, LYPLAL1 does not depalmitoylate the oncogene Ras and a structural and enzymatic study concluded that LYPLAL1 is generally unable to act as a lipase and is instead an esterase that prefers short-chain substrates, such as acetyl groups.
# Relationship to acyl-protein thioesterases
Sequence conservation and structural homology suggest a close relationship of LYPLAL1 proteins to acyl-protein thioesterases, and, therefore, it has been suggested that LYPLAL1 might be the third human acyl-protein thioesterase. However, the major structural difference between both protein families has been established in the hydrophobic substrate binding tunnel, which has been identified in human acyl-protein thioesterases 1 and 2, as well as in Zea mays acyl-protein thioesterase 2. In LYPLAL1, this tunnel is closed due to a different loop conformation, changing the enzyme's substrate specificity to short acyl chains.
# Model organisms
Model organisms have been used in the study of LYPLAL1 function. A conditional knockout mouse line called Lyplal1tm1a(KOMP)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 | LYPLAL1
Lysophospholipase-like 1 is a protein in humans that is encoded by the LYPLAL1 gene.
[1] The protein is a α/β-hydrolase of uncharacterized metabolic function. Genome-wide association studies in humans have linked the gene to fat distribution[2] and waist-to-hip ratio.[3] The protein's enzymatic function is unclear. LYPLAL1 was reported to act as a triglyceride lipase in adipose tissue[4] and another study suggested that the protein may play a role in the depalmitoylation of calcium-activated potassium channels.[5] However, LYPLAL1 does not depalmitoylate the oncogene Ras[6] and a structural and enzymatic study concluded that LYPLAL1 is generally unable to act as a lipase and is instead an esterase that prefers short-chain substrates, such as acetyl groups.[7]
# Relationship to acyl-protein thioesterases
Sequence conservation and structural homology suggest a close relationship of LYPLAL1 proteins to acyl-protein thioesterases, and, therefore, it has been suggested that LYPLAL1 might be the third human acyl-protein thioesterase.[8] However, the major structural difference between both protein families has been established in the hydrophobic substrate binding tunnel, which has been identified in human acyl-protein thioesterases 1[9] and 2,[10] as well as in Zea mays acyl-protein thioesterase 2.[11] In LYPLAL1, this tunnel is closed due to a different loop conformation, changing the enzyme's substrate specificity to short acyl chains.[7]
# Model organisms
Model organisms have been used in the study of LYPLAL1 function. A conditional knockout mouse line called Lyplal1tm1a(KOMP)Wtsi was generated at the Wellcome Trust Sanger Institute.[12] Male and female animals underwent a standardized phenotypic screen[13] to determine the effects of deletion.[14][15][16][17] Additional screens performed: - In-depth immunological phenotyping[18] | https://www.wikidoc.org/index.php/LYPLAL1 | |
730fc80ab03a52013b50e2eb68af5ab20781c05d | wikidoc | Lactase | Lactase
Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness. Lacking lactase, a person consuming dairy products may experience the symptoms of lactose intolerance. Lactase can be purchased as a food supplement, and is added to milk to produce "lactose-free" milk products.
Lactase (also known as lactase-phlorizin hydrolase, or LPH), a part of the β-galactosidase family of enzymes, is a glycoside hydrolase involved in the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers. Lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine. In humans, lactase is encoded by the LCT gene.
# Uses
## Food use
Lactase is an enzyme that some people are unable to produce in their small intestine. Without it they can't break down the natural lactose in milk, leaving them with diarrhea, gas and bloating when drinking regular milk. Technology to produce lactose-free milk, ice cream and yogurt was developed by the USDA Agricultural Research Service in 1985. This technology is used to add lactase to milk, thereby hydrolyzing the lactose naturally found in milk, leaving it slightly sweet but digestible by everyone. Without lactase, lactose intolerant people pass the lactose undigested to the colon where bacteria break it down creating carbon dioxide and that leads to bloating and flatulence.
## Medical use
Lactase supplements are sometimes used to treat lactose intolerance.
## Industrial use
Lactase produced commercially can be extracted both from yeasts such as Kluyveromyces fragilis and Kluyveromyces lactis and from molds, such as Aspergillus niger and Aspergillus oryzae. Its primary commercial use, in supplements such as Lacteeze and Lactaid, is to break down lactose in milk to make it suitable for people with lactose intolerance, However, the U.S. Food and Drug Administration has not formally evaluated the effectiveness of these products.
Lactase is also used to screen for blue white colonies in the multiple cloning sites of various plasmid vectors in Escherichia coli or other bacteria.
# Mechanism
The optimum temperature for human lactase is about 37 °C for its activity and has an optimum pH of 6.
In metabolism, the β-glycosidic bond in D-lactose is hydrolyzed to form D-galactose and D-glucose, which can be absorbed through the intestinal walls and into the bloodstream. The overall reaction that lactase catalyzes is C12H22O11 + H2O → C6H12O6 + C6H12O6 + heat.
The catalytic mechanism of D-lactose hydrolysis retains the substrate anomeric configuration in the products. While the details of the mechanism are uncertain, the stereochemical retention is achieved through a double displacement reaction. Studies of E. coli lactase have proposed that hydrolysis is initiated when a glutamate nucleophile on the enzyme attacks from the axial side of the galactosyl carbon in the β-glycosidic bond. The removal of the D-glucose leaving group may be facilitated by Mg-dependent acid catalysis. The enzyme is liberated from the α-galactosyl moiety upon equatorial nucleophilic attack by water, which produces D-galactose.
Substrate modification studies have demonstrated that the 3′-OH and 2′-OH moieties on the galactopyranose ring are essential for enzymatic recognition and hydrolysis. The 3′-hydroxy group is involved in initial binding to the substrate while the 2′- group is not necessary for recognition but needed in subsequent steps. This is demonstrated by the fact that a 2-deoxy analog is an effective competitive inhibitor (Ki = 10mM). Elimination of specific hydroxyl groups on the glucopyranose moiety does not completely eliminate catalysis.
Proposed mechanism of lactose hydrolysis by Lactase enzyme
Lactase also catalyzes the conversion of phlorizin to phloretin and glucose.
# Structure and biosynthesis
Preprolactase, the primary translation product, has a single polypeptide primary structure consisting of 1927 amino acids. It can be divided into five domains: (i) a 19-amino-acid cleaved signal sequence; (ii) a large prosequence domain that is not present in mature lactase; (iii) the mature lactase segment; (iv) a membrane-spanning hydrophobic anchor; and (v) a short hydrophilic carboxyl terminus. The signal sequence is cleaved in the endoplasmic reticulum, and the resulting 215-kDa pro-LPH is sent to the Golgi apparatus, where it is heavily glycosylated and proteolytically processed to its mature form. The prodomain has been shown to act as an intramolecular chaperone in the ER, preventing trypsin cleavage and allowing LPH to adopt the necessary 3-D structure to be transported to the Golgi apparatus.
Mature human lactase consists of a single 160-kDa polypeptide chain that localizes to the brush border membrane of intestinal epithelial cells. It is oriented with the N-terminus outside the cell and the C-terminus in the cytosol. LPH contains two catalytic glutamic acid sites. In the human enzyme, the lactase activity has been connected to Glu-1749, while Glu-1273 is the site of phlorizin hydrolase function.
# Genetic expression and regulation
Lactase is encoded by a single genetic locus on chromosome 2. It is expressed exclusively by mammalian small intestine enterocytes and in very low levels in the colon during fetal development. Humans are born with high levels of lactase expression. In most of the world’s population, lactase transcription is down-regulated after weaning, resulting in diminished lactase expression in the small intestine, which causes the common symptoms of adult-type hypolactasia, or lactose intolerance.
Some population segments exhibit lactase persistence resulting from a mutation that is postulated to have occurred 5,000–10,000 years ago, coinciding with the rise of cattle domestication. This mutation has allowed almost half of the world’s population to metabolize lactose without symptoms. Studies have linked the occurrence of lactase persistence to two different single-nucleotide polymorphisms about 14 and 22 kilobases upstream of the 5’-end of the LPH gene. Both mutations, C→T at position -13910 and G→ A at position -22018, have been independently linked to lactase persistence.
The lactase promoter is 150 base pairs long and is located just upstream of the site of transcription initiation. The sequence is highly conserved in mammals, suggesting that critical cis-transcriptional regulators are located nearby. Cdx-2, HNF-1α, and GATA have been identified as transcription factors. Studies of hypolactasia onset have demonstrated that despite polymorphisms, little difference exists in lactase expression in infants, showing that the mutations become increasingly relevant during development. Developmentally regulated DNA-binding proteins may down-regulate transcription or destabilize mRNA transcripts, causing decreased LPH expression after weaning. | Lactase
Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives milk its sweetness. Lacking lactase, a person consuming dairy products may experience the symptoms of lactose intolerance.[1] Lactase can be purchased as a food supplement, and is added to milk to produce "lactose-free" milk products.
Lactase (also known as lactase-phlorizin hydrolase, or LPH), a part of the β-galactosidase family of enzymes, is a glycoside hydrolase involved in the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers. Lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine.[2] In humans, lactase is encoded by the LCT gene.[3][4]
# Uses
## Food use
Lactase is an enzyme that some people are unable to produce in their small intestine.[5] Without it they can't break down the natural lactose in milk, leaving them with diarrhea, gas and bloating when drinking regular milk. Technology to produce lactose-free milk, ice cream and yogurt was developed by the USDA Agricultural Research Service in 1985.[6] This technology is used to add lactase to milk, thereby hydrolyzing the lactose naturally found in milk, leaving it slightly sweet but digestible by everyone.[7] Without lactase, lactose intolerant people pass the lactose undigested to the colon[citation needed] where bacteria break it down creating carbon dioxide and that leads to bloating and flatulence.
## Medical use
Lactase supplements are sometimes used to treat lactose intolerance.[8]
## Industrial use
Lactase produced commercially can be extracted both from yeasts such as Kluyveromyces fragilis and Kluyveromyces lactis and from molds, such as Aspergillus niger and Aspergillus oryzae.[9] Its primary commercial use, in supplements such as Lacteeze and Lactaid, is to break down lactose in milk to make it suitable for people with lactose intolerance,[10][11] However, the U.S. Food and Drug Administration has not formally evaluated the effectiveness of these products.[12]
Lactase is also used to screen for blue white colonies in the multiple cloning sites of various plasmid vectors in Escherichia coli or other bacteria.[13]
# Mechanism
The optimum temperature for human lactase is about 37 °C for its activity[14] and has an optimum pH of 6.[2]
In metabolism, the β-glycosidic bond in D-lactose is hydrolyzed to form D-galactose and D-glucose, which can be absorbed through the intestinal walls and into the bloodstream. The overall reaction that lactase catalyzes is C12H22O11 + H2O → C6H12O6 + C6H12O6 + heat.
The catalytic mechanism of D-lactose hydrolysis retains the substrate anomeric configuration in the products.[15] While the details of the mechanism are uncertain, the stereochemical retention is achieved through a double displacement reaction. Studies of E. coli lactase have proposed that hydrolysis is initiated when a glutamate nucleophile on the enzyme attacks from the axial side of the galactosyl carbon in the β-glycosidic bond.[16] The removal of the D-glucose leaving group may be facilitated by Mg-dependent acid catalysis.[16] The enzyme is liberated from the α-galactosyl moiety upon equatorial nucleophilic attack by water, which produces D-galactose.[15]
Substrate modification studies have demonstrated that the 3′-OH and 2′-OH moieties on the galactopyranose ring are essential for enzymatic recognition and hydrolysis.[17] The 3′-hydroxy group is involved in initial binding to the substrate while the 2′- group is not necessary for recognition but needed in subsequent steps. This is demonstrated by the fact that a 2-deoxy analog is an effective competitive inhibitor (Ki = 10mM).[17] Elimination of specific hydroxyl groups on the glucopyranose moiety does not completely eliminate catalysis.[17]
Proposed mechanism of lactose hydrolysis by Lactase enzyme
Lactase also catalyzes the conversion of phlorizin to phloretin and glucose.
# Structure and biosynthesis
Preprolactase, the primary translation product, has a single polypeptide primary structure consisting of 1927 amino acids.[3] It can be divided into five domains: (i) a 19-amino-acid cleaved signal sequence; (ii) a large prosequence domain that is not present in mature lactase; (iii) the mature lactase segment; (iv) a membrane-spanning hydrophobic anchor; and (v) a short hydrophilic carboxyl terminus.[3] The signal sequence is cleaved in the endoplasmic reticulum, and the resulting 215-kDa pro-LPH is sent to the Golgi apparatus, where it is heavily glycosylated and proteolytically processed to its mature form.[18] The prodomain has been shown to act as an intramolecular chaperone in the ER, preventing trypsin cleavage and allowing LPH to adopt the necessary 3-D structure to be transported to the Golgi apparatus.[19]
Mature human lactase consists of a single 160-kDa polypeptide chain that localizes to the brush border membrane of intestinal epithelial cells. It is oriented with the N-terminus outside the cell and the C-terminus in the cytosol.[3] LPH contains two catalytic glutamic acid sites. In the human enzyme, the lactase activity has been connected to Glu-1749, while Glu-1273 is the site of phlorizin hydrolase function.[20]
# Genetic expression and regulation
Lactase is encoded by a single genetic locus on chromosome 2.[21] It is expressed exclusively by mammalian small intestine enterocytes and in very low levels in the colon during fetal development.[21] Humans are born with high levels of lactase expression. In most of the world’s population, lactase transcription is down-regulated after weaning, resulting in diminished lactase expression in the small intestine,[21] which causes the common symptoms of adult-type hypolactasia, or lactose intolerance.[22]
Some population segments exhibit lactase persistence resulting from a mutation that is postulated to have occurred 5,000–10,000 years ago, coinciding with the rise of cattle domestication.[23] This mutation has allowed almost half of the world’s population to metabolize lactose without symptoms. Studies have linked the occurrence of lactase persistence to two different single-nucleotide polymorphisms about 14 and 22 kilobases upstream of the 5’-end of the LPH gene.[24] Both mutations, C→T at position -13910 and G→ A at position -22018, have been independently linked to lactase persistence.[25]
The lactase promoter is 150 base pairs long and is located just upstream of the site of transcription initiation.[25] The sequence is highly conserved in mammals, suggesting that critical cis-transcriptional regulators are located nearby.[25] Cdx-2, HNF-1α, and GATA have been identified as transcription factors.[25] Studies of hypolactasia onset have demonstrated that despite polymorphisms, little difference exists in lactase expression in infants, showing that the mutations become increasingly relevant during development.[26] Developmentally regulated DNA-binding proteins may down-regulate transcription or destabilize mRNA transcripts, causing decreased LPH expression after weaning.[26] | https://www.wikidoc.org/index.php/Lactase | |
cb6948617ffdfa0fb5ab9cbdbfff219fb8886e76 | wikidoc | Lacteal | Lacteal
# Overview
A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine.
The combination of fat and lymph in the lacteals is milky in appearance and called chyle. Individual lacteals merge to form larger lymphatic vessels that transport the fats to the thoracic duct which empties into the left subclavian vein.
At this point, the fats are in the bloodstream. They can be converted to lipoproteins (HDL, LDL or VLDL) in the liver or be transported to tissues throughout the body and stored in adipose cells as triglycerides. | Lacteal
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Template:Infobox Anatomy
A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine.
The combination of fat and lymph in the lacteals is milky in appearance and called chyle. Individual lacteals merge to form larger lymphatic vessels that transport the fats to the thoracic duct which empties into the left subclavian vein.
At this point, the fats are in the bloodstream. They can be converted to lipoproteins (HDL, LDL or VLDL) in the liver or be transported to tissues throughout the body and stored in adipose cells as triglycerides. | https://www.wikidoc.org/index.php/Lacteal | |
986769508e479ec444585b8b36c64e694bf238ad | wikidoc | Lactone | Lactone
A lactone is a cyclic ester in organic chemistry . It is the condensation product of an alcohol group and a carboxylic acid group in the same molecule. The most stable structure for lactones are the 5-membered lactones (gamma-lactone) and 6-membered lactones (delta-lactone), because of the minimal angle strain in the compounds' structure. Gamma-lactones are so stable that 4-hydroxy acids (R-CH(OH)-(CH2)2-COOH) are unstable in the presence of dilute acids at room temperature, immediately undergoing spontaneous esterification and cyclisation to the lactone. Beta-lactones do exist, but can only be made by special methods.
# Etymology
The name lactone derives from the ring compound called lactide, which is formed from the dehydration of 2-hydroxypropanoic acid (lactic acid) CH3-CH(OH)-COOH. Lactic acid, in turn, derives its name from its original isolation from soured milk (latin: lac, lactis). An internal dehydration within the same molecule of lactic acid would have produced a 3-membered lactone which is unstable.
# Nomenclature
Lactones are named by labelling the carbon atoms in the chain of the lactones' precursor compounds. The first carbon atom after the carbon in the -COOH group on the parent compound is labelled alpha, the second will be labelled beta and so forth. The lactone formed will be named after the carbon atom which is connected to the -OH (hydroxy) group that the -COOH group reacts with, and this will determine the prefix of the lactone. The prefixes also indicate the ring size: beta-lactone (4-membered), gamma-lactone (5-membered), delta-lactone (6-membered ring).
# Synthesis
Many methods in ester synthesis can also be applied to that of lactones. In one industrial synthesis of oxandrolone the key lactone-forming step is an organic reduction - esterfication :
In halolactonization, an alkene is attacked by a halogen via electrophilic addition with the cationic intermediate captured intramolecularly by an adjacent carboxylic acid (See also iodolactamization), for example in this iodolactonization :
# Reactions
The reactions of lactones are similar to those of esters, as exemplified by gamma-lactone in the following sections:
## Hydrolysis
Heating a lactone with a base (sodium hydroxide) will hydrolyse the lactone to its parent compound, the straight chained bifunctional compound. Like straight-chained esters, the hydrolysis-condensation reaction of lactones is a reversible reaction, with an equilibrium. However, the equilibrium constant of the hydrolysis reaction of the lactone is higher than that of the straight-chained ester i.e. the products (hydroxyacids) are favoured in the case of the lactones. This is because although the enthalpies of the hydrolysis of esters and lactones are about the same, the entropy of the hydrolysis of lactones is less than the entropy of straight-chained esters.
## Reduction
Lactones can be reduced to diols using lithium aluminium hydride in dry ether. The reduction reaction will first break the ester bond of the lactone and then, reduce the carboxylic acid group (-COOH) to the alcohol group (-OH). Gamma-lactones, for instance, will be reduced to butane-1,4-diol, (CH2(OH)-(CH2)2-CH2(OH)
## Ammonolysis
Lactones also react with ethanolic ammonia, which will first break the ester bond and then react with the acidic -COOH group, because of the basic properties of ammonia, to form a difunctional group, i.e. alcohol and amide. Gamma-lactones will react to yield CH2(OH)-(CH2)2-CO-NH2.
# Examples
- β-propiolactone
β-propiolactone
- γ-butyrolactone (GBL)
γ-butyrolactone (GBL)
- D-glucono-δ-lactone (E575)
D-glucono-δ-lactone (E575)
- ε-caprolactone
ε-caprolactone | Lactone
A lactone is a cyclic ester in organic chemistry [1]. It is the condensation product of an alcohol group and a carboxylic acid group in the same molecule. The most stable structure for lactones are the 5-membered lactones (gamma-lactone) and 6-membered lactones (delta-lactone), because of the minimal angle strain in the compounds' structure. Gamma-lactones are so stable that 4-hydroxy acids (R-CH(OH)-(CH2)2-COOH) are unstable in the presence of dilute acids at room temperature, immediately undergoing spontaneous esterification and cyclisation to the lactone. Beta-lactones do exist, but can only be made by special methods.
# Etymology
The name lactone derives from the ring compound called lactide, which is formed from the dehydration of 2-hydroxypropanoic acid (lactic acid) CH3-CH(OH)-COOH. Lactic acid, in turn, derives its name from its original isolation from soured milk (latin: lac, lactis). An internal dehydration within the same molecule of lactic acid would have produced a 3-membered lactone which is unstable.
# Nomenclature
Lactones are named by labelling the carbon atoms in the chain of the lactones' precursor compounds. The first carbon atom after the carbon in the -COOH group on the parent compound is labelled alpha, the second will be labelled beta and so forth. The lactone formed will be named after the carbon atom which is connected to the -OH (hydroxy) group that the -COOH group reacts with, and this will determine the prefix of the lactone. The prefixes also indicate the ring size: beta-lactone (4-membered), gamma-lactone (5-membered), delta-lactone (6-membered ring).
# Synthesis
Many methods in ester synthesis can also be applied to that of lactones. In one industrial synthesis of oxandrolone the key lactone-forming step is an organic reduction - esterfication [2] [3]:
In halolactonization, an alkene is attacked by a halogen via electrophilic addition with the cationic intermediate captured intramolecularly by an adjacent carboxylic acid (See also iodolactamization), for example in this iodolactonization [4]:
# Reactions
The reactions of lactones are similar to those of esters, as exemplified by gamma-lactone in the following sections:
## Hydrolysis
Heating a lactone with a base (sodium hydroxide) will hydrolyse the lactone to its parent compound, the straight chained bifunctional compound. Like straight-chained esters, the hydrolysis-condensation reaction of lactones is a reversible reaction, with an equilibrium. However, the equilibrium constant of the hydrolysis reaction of the lactone is higher than that of the straight-chained ester i.e. the products (hydroxyacids) are favoured in the case of the lactones. This is because although the enthalpies of the hydrolysis of esters and lactones are about the same, the entropy of the hydrolysis of lactones is less than the entropy of straight-chained esters.
## Reduction
Lactones can be reduced to diols using lithium aluminium hydride in dry ether. The reduction reaction will first break the ester bond of the lactone and then, reduce the carboxylic acid group (-COOH) to the alcohol group (-OH). Gamma-lactones, for instance, will be reduced to butane-1,4-diol, (CH2(OH)-(CH2)2-CH2(OH)
## Ammonolysis
Lactones also react with ethanolic ammonia, which will first break the ester bond and then react with the acidic -COOH group, because of the basic properties of ammonia, to form a difunctional group, i.e. alcohol and amide. Gamma-lactones will react to yield CH2(OH)-(CH2)2-CO-NH2.
# Examples
- β-propiolactone
β-propiolactone
- γ-butyrolactone (GBL)
γ-butyrolactone (GBL)
- D-glucono-δ-lactone (E575)
D-glucono-δ-lactone (E575)
- ε-caprolactone
ε-caprolactone | https://www.wikidoc.org/index.php/Lactone | |
5473ab538e20250c0c74db931fb09b5d18a67b12 | wikidoc | Laetoli | Laetoli
Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominid footprints, preserved in volcanic ash (Site G). The site of the Laetoli footprints is located 45 km south of Olduvai gorge. Professor Terry Harrison, a physical anthropologist at New York University, has continued research at the site since the late 1990s.
# Date
The footprint-bearing layers are Pliocene in age, dated by the K/Ar method to 3.7 million years ago (m.y.a.).
# The footprints
A line of hominid fossil footprints, discovered in 1978 by Mary Leakey, Richard Hay, Tim White and their team, is preserved in powdery volcanic ash from an eruption of the 20 km distant Sadiman Volcano. Soft rain cemented the ash-layer (15 cm thick) to tuff without destroying the prints. In time, they were covered by other ash deposits. The hominid prints were produced by three individuals, one walking in the footprints of the other, making the original tracks difficult to discover. As the tracks lead in the same direction, they might have been produced by a group -- but there is nothing else to support the common reconstruction of a nuclear family visiting the waterhole together.
The footprints demonstrate that the hominids walked upright habitually, as there are no knuckle-impressions. The feet do not have the mobile big toe of apes; instead, they have an arch (the bending of the sole of the foot) typical of modern humans. The hominids seem to have moved in a leisurely stroll.
# Other animals
Other prints show the presence of twenty other animal species, among them hyenas, wild cats (Machairodont), baboons, wild boar, giraffes, gazelles, rhinos, several kinds of antelope, hipparion, buffalo, elephants (of the extinct Deinotherium genus), hare and birds. Traces of raindrops can be seen as well. Few prints are superimposed, which indicates that they were rapidly covered up again. Most of these animals are represented by skeletal remains in the area as well.
# Human remains
The German anthropologist Ludwig Kohl-Larsen was the first to go to Laetoli to look for fossil remains. In 1934 he found the jaw of Australopithecus afarensis.
The remains of 13 hominids have been found, mainly mandibles and teeth. They show affinities to the female skeleton Lucy from Hadar, Ethiopia. Most scholars classify them as Australopithecus afarensis, but some stress the greater similarity to Homo and prefer to speak of Homo sp. indet.
A rather complete skull found at Ngaloba in 1976 has been dated to ca. 120,000 to 100,000 years ago. It is very modern anatomically, with a cranial capacity of ca. 1200 cm³, but the forehead is still very low.
# Artifacts
No artifacts have been found in the vicinity.
# Further reading
- Mary D. Leakey and J. M. Harris (eds), Laetoli: a Pliocene site in Northern Tanzania (Oxford, Clarendon Press 1987). ISBN 0-19-854441-3.
- Richard L. Hay and Mary D. Leakey, "Fossil footprints of Laetoli." Scientific American, February 1982, 50-57. | Laetoli
Laetoli is a site in Tanzania, dated to the Plio-Pleistocene and famous for its hominid footprints, preserved in volcanic ash (Site G). The site of the Laetoli footprints is located 45 km south of Olduvai gorge. Professor Terry Harrison, a physical anthropologist at New York University, has continued research at the site since the late 1990s.
# Date
The footprint-bearing layers are Pliocene in age, dated by the K/Ar method to 3.7 million years ago (m.y.a.).
# The footprints
A line of hominid fossil footprints, discovered in 1978 by Mary Leakey, Richard Hay, Tim White and their team, is preserved in powdery volcanic ash from an eruption of the 20 km distant Sadiman Volcano. Soft rain cemented the ash-layer (15 cm thick) to tuff without destroying the prints. In time, they were covered by other ash deposits. The hominid prints were produced by three individuals, one walking in the footprints of the other, making the original tracks difficult to discover. As the tracks lead in the same direction, they might have been produced by a group -- but there is nothing else to support the common reconstruction of a nuclear family visiting the waterhole together.
The footprints demonstrate that the hominids walked upright habitually, as there are no knuckle-impressions. The feet do not have the mobile big toe of apes; instead, they have an arch (the bending of the sole of the foot) typical of modern humans. The hominids seem to have moved in a leisurely stroll.
# Other animals
Other prints show the presence of twenty other animal species, among them hyenas, wild cats (Machairodont), baboons, wild boar, giraffes, gazelles, rhinos, several kinds of antelope, hipparion, buffalo, elephants (of the extinct Deinotherium genus), hare and birds. Traces of raindrops can be seen as well. Few prints are superimposed, which indicates that they were rapidly covered up again. Most of these animals are represented by skeletal remains in the area as well.
# Human remains
The German anthropologist Ludwig Kohl-Larsen was the first to go to Laetoli to look for fossil remains. In 1934 he found the jaw of Australopithecus afarensis.[1]
The remains of 13 hominids have been found, mainly mandibles and teeth. They show affinities to the female skeleton Lucy from Hadar, Ethiopia. Most scholars classify them as Australopithecus afarensis, but some stress the greater similarity to Homo and prefer to speak of Homo sp. indet.
A rather complete skull found at Ngaloba in 1976 has been dated to ca. 120,000 to 100,000 years ago. It is very modern anatomically, with a cranial capacity of ca. 1200 cm³, but the forehead is still very low.
# Artifacts
No artifacts have been found in the vicinity.
# Further reading
- Mary D. Leakey and J. M. Harris (eds), Laetoli: a Pliocene site in Northern Tanzania (Oxford, Clarendon Press 1987). ISBN 0-19-854441-3.
- Richard L. Hay and Mary D. Leakey, "Fossil footprints of Laetoli." Scientific American, February 1982, 50-57. | https://www.wikidoc.org/index.php/Laetoli | |
742ea83083224acfe12aa1b358818b6c341648dd | wikidoc | Lanolin | Lanolin
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
NOTE: Most over the counter (OTC) are not reviewed and approved by the FDA. However, they may be marketed if they comply with applicable regulations and policies. FDA has not evaluated whether this product complies.
# Overview
Lanolin is a non-petroleum based lubricants that is FDA approved for the treatment of diaper dermatitis and protection of chafed skin or minor skin irritations due to incontinence. Common adverse reactions include burning, stinging, redness and irritation.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
There is limited information regarding FDA-Label Guideline-Supported Use of Lanolin in adult patients.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Lanolin in adult patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Lanolin in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
# Indications
- Helps prevent and treat diaper dermatitis
- Protects chafed skin or minor skin irritations due to incontinence and helps seal out wetness.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Lanolin in pediatric patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Lanolin in pediatric patients.
# Contraindications
There is limited information regarding Lanolin Contraindications in the drug label.
# Warnings
- For External Use Only
- Avoid contact with eyes
- Do not apply to deep or puncture wounds
- If condition worsens, or does not improve within 7 days, consult a doctor
KEEP OUT OF REACH OF CHILDREN
- If swallowed, get medical help or contact a Poison Control Center right away
# Adverse Reactions
## Clinical Trials Experience
- There is limited information regarding Clinical Trial Experience of Lanolin in the drug label.
## Postmarketing Experience
- There is limited information regarding Postmarketing Experience of Lanolin in the drug label.
# Drug Interactions
There is limited information regarding Lanolin Drug Interactions in the drug label.
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA):
There is no FDA guidance on usage of Lanolin in women who are pregnant.
Pregnancy Category (AUS):
- There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Lanolin in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Lanolin during labor and delivery.
### Nursing Mothers
There is no FDA guidance on the use of Lanolin with respect to nursing mothers.
### Pediatric Use
There is no FDA guidance on the use of Lanolin with respect to pediatric patients.
### Geriatic Use
There is no FDA guidance on the use of Lanolin with respect to geriatric patients.
### Gender
There is no FDA guidance on the use of Lanolin with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Lanolin with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Lanolin in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Lanolin in patients with hepatic impairment.
### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Lanolin in women of reproductive potentials and males.
### Immunocompromised Patients
There is no FDA guidance one the use of Lanolin in patients who are immunocompromised.
# Administration and Monitoring
### Administration
- Topical
- Gently cleanse and dry area
- Apply liberally to affected area as needed
- Avoid contact with eyes
- Do not apply to deep or puncture wounds
- If condition worsens, or does not improve within 7 days, consult a doctor
### Monitoring
- There is limited information regarding Monitoring of Lanolin in the drug label.
# IV Compatibility
- There is limited information regarding IV Compatibility of Lanolin in the drug label.
# Overdosage
- There is limited information regarding Chronic Overdose of Lanolin in the drug label.
# Pharmacology
There is limited information regarding Lanolin Pharmacology in the drug label.
## Mechanism of Action
There is limited information regarding Lanolin Mechanism of Action in the drug label.
## Structure
There is limited information regarding Lanolin Structure in the drug label.
## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Lanolin in the drug label.
## Pharmacokinetics
There is limited information regarding Pharmacokinetics of Lanolin in the drug label.
## Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Lanolin in the drug label.
# Clinical Studies
There is limited information regarding Clinical Studies of Lanolin in the drug label.
# How Supplied
There is limited information regarding Lanolin How Supplied in the drug label.
## Storage
- Store at room temperature 20 deg C to 25 deg C 68 deg F to 77 deg F
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
There is limited information regarding Patient Counseling Information of Lanolin in the drug label.
# Precautions with Alcohol
- Alcohol-Lanolin interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- LANOLIN ®
# Look-Alike Drug Names
- A® — B®
# Drug Shortage Status
# Price | Lanolin
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2]
# Disclaimer
WikiDoc MAKES NO GUARANTEE OF VALIDITY. WikiDoc is not a professional health care provider, nor is it a suitable replacement for a licensed healthcare provider. WikiDoc is intended to be an educational tool, not a tool for any form of healthcare delivery. The educational content on WikiDoc drug pages is based upon the FDA package insert, National Library of Medicine content and practice guidelines / consensus statements. WikiDoc does not promote the administration of any medication or device that is not consistent with its labeling. Please read our full disclaimer here.
NOTE: Most over the counter (OTC) are not reviewed and approved by the FDA. However, they may be marketed if they comply with applicable regulations and policies. FDA has not evaluated whether this product complies.
# Overview
Lanolin is a non-petroleum based lubricants that is FDA approved for the treatment of diaper dermatitis and protection of chafed skin or minor skin irritations due to incontinence. Common adverse reactions include burning, stinging, redness and irritation.
# Adult Indications and Dosage
## FDA-Labeled Indications and Dosage (Adult)
There is limited information regarding FDA-Label Guideline-Supported Use of Lanolin in adult patients.
## Off-Label Use and Dosage (Adult)
### Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Lanolin in adult patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Lanolin in adult patients.
# Pediatric Indications and Dosage
## FDA-Labeled Indications and Dosage (Pediatric)
# Indications
- Helps prevent and treat diaper dermatitis
- Protects chafed skin or minor skin irritations due to incontinence and helps seal out wetness.
## Off-Label Use and Dosage (Pediatric)
### Guideline-Supported Use
- There is limited information regarding Off-Label Guideline-Supported Use of Lanolin in pediatric patients.
### Non–Guideline-Supported Use
- There is limited information regarding Off-Label Non–Guideline-Supported Use of Lanolin in pediatric patients.
# Contraindications
There is limited information regarding Lanolin Contraindications in the drug label.
# Warnings
- For External Use Only
- Avoid contact with eyes
- Do not apply to deep or puncture wounds
- If condition worsens, or does not improve within 7 days, consult a doctor
KEEP OUT OF REACH OF CHILDREN
- If swallowed, get medical help or contact a Poison Control Center right away
# Adverse Reactions
## Clinical Trials Experience
- There is limited information regarding Clinical Trial Experience of Lanolin in the drug label.
## Postmarketing Experience
- There is limited information regarding Postmarketing Experience of Lanolin in the drug label.
# Drug Interactions
There is limited information regarding Lanolin Drug Interactions in the drug label.
# Use in Specific Populations
### Pregnancy
Pregnancy Category (FDA):
There is no FDA guidance on usage of Lanolin in women who are pregnant.
Pregnancy Category (AUS):
- There is no Australian Drug Evaluation Committee (ADEC) guidance on usage of Lanolin in women who are pregnant.
### Labor and Delivery
There is no FDA guidance on use of Lanolin during labor and delivery.
### Nursing Mothers
There is no FDA guidance on the use of Lanolin with respect to nursing mothers.
### Pediatric Use
There is no FDA guidance on the use of Lanolin with respect to pediatric patients.
### Geriatic Use
There is no FDA guidance on the use of Lanolin with respect to geriatric patients.
### Gender
There is no FDA guidance on the use of Lanolin with respect to specific gender populations.
### Race
There is no FDA guidance on the use of Lanolin with respect to specific racial populations.
### Renal Impairment
There is no FDA guidance on the use of Lanolin in patients with renal impairment.
### Hepatic Impairment
There is no FDA guidance on the use of Lanolin in patients with hepatic impairment.
### Females of Reproductive Potential and Males
There is no FDA guidance on the use of Lanolin in women of reproductive potentials and males.
### Immunocompromised Patients
There is no FDA guidance one the use of Lanolin in patients who are immunocompromised.
# Administration and Monitoring
### Administration
- Topical
- Gently cleanse and dry area
- Apply liberally to affected area as needed
- Avoid contact with eyes
- Do not apply to deep or puncture wounds
- If condition worsens, or does not improve within 7 days, consult a doctor
### Monitoring
- There is limited information regarding Monitoring of Lanolin in the drug label.
# IV Compatibility
- There is limited information regarding IV Compatibility of Lanolin in the drug label.
# Overdosage
- There is limited information regarding Chronic Overdose of Lanolin in the drug label.
# Pharmacology
There is limited information regarding Lanolin Pharmacology in the drug label.
## Mechanism of Action
There is limited information regarding Lanolin Mechanism of Action in the drug label.
## Structure
There is limited information regarding Lanolin Structure in the drug label.
## Pharmacodynamics
There is limited information regarding Pharmacodynamics of Lanolin in the drug label.
## Pharmacokinetics
There is limited information regarding Pharmacokinetics of Lanolin in the drug label.
## Nonclinical Toxicology
There is limited information regarding Nonclinical Toxicology of Lanolin in the drug label.
# Clinical Studies
There is limited information regarding Clinical Studies of Lanolin in the drug label.
# How Supplied
There is limited information regarding Lanolin How Supplied in the drug label.
## Storage
- Store at room temperature 20 deg C to 25 deg C 68 deg F to 77 deg F
# Images
## Drug Images
## Package and Label Display Panel
# Patient Counseling Information
There is limited information regarding Patient Counseling Information of Lanolin in the drug label.
# Precautions with Alcohol
- Alcohol-Lanolin interaction has not been established. Talk to your doctor about the effects of taking alcohol with this medication.
# Brand Names
- LANOLIN ®[1]
# Look-Alike Drug Names
- A® — B®[2]
# Drug Shortage Status
# Price | https://www.wikidoc.org/index.php/Lanolin | |
cd4c18729f98291df7df99af240aa657fd32f822 | wikidoc | Lapsana | Lapsana
Lapsana is a genus of flowering plants in the family Asteraceae, containing a single species, Lapsana communis (Nipplewort). It is native to Europe and northern Asia.
It is an annual or perennial herbaceous plant growing to 1-1.2 m tall, with hairy stems and clear (not milky) sap. The leaves are spirally arranged; larger leaves at the base of the flowering stem are often pinnate, with a large oval terminal leaflet and one to four small side leaflets, while smaller leaves higher on the stem are simple oval; all leaves have a toothed margin. The flowers are yellow, produced in a capitulum 1-2 cm diameter, the capitula being numerous in loose clusters at the top of the stem.
There are six subspecies:
- Lapsana communis subsp. communis. Most of Europe, except the southeast. Annual.
- Lapsana communis subsp. adenophora (Boiss.) Rech.f. Southeast Europe.
- Lapsana communis subsp. alpina (Boiss. & Balansa) P.D.Sell. Crimea.
- Lapsana communis subsp. grandiflora (M. Bieb.) P.D.Sell. Southwest Asia.
- Lapsana communis subsp. intermedia (M. Bieb.) Hayek. Southwest Asia, southeast Europe. Perennial.
- Lapsana communis subsp. pisidica (Boiss. & Heldr.) Rech.f. Greece.
In the past, a number of other species were included in the genus; these species are now treated in the genera Crepis and Lapsanastrum.
# Cultivation and uses
The young leaves are edible, and can be used in salads or cooked like spinach. The scientific name comes from Lapsane, an edible herb described by Marcus Terentius Varro of ancient Rome. The English name 'Nipplewort' derives from its closed flower buds, which resemble nipples. Because of its resemblance to nipples, under the doctrine of signatures it was once used as treatment for breast ulcers.
Away from its native area, Lapsana communis is naturalised, and sometimes considered an invasive species, in many areas around the world, including Australia, Chile, New Zealand, and most of North America. | Lapsana
Lapsana is a genus of flowering plants in the family Asteraceae, containing a single species, Lapsana communis (Nipplewort). It is native to Europe and northern Asia.
It is an annual or perennial herbaceous plant growing to 1-1.2 m tall, with hairy stems and clear (not milky) sap. The leaves are spirally arranged; larger leaves at the base of the flowering stem are often pinnate, with a large oval terminal leaflet and one to four small side leaflets, while smaller leaves higher on the stem are simple oval; all leaves have a toothed margin. The flowers are yellow, produced in a capitulum 1-2 cm diameter, the capitula being numerous in loose clusters at the top of the stem.[1][2]
There are six subspecies:[3][4][1]
- Lapsana communis subsp. communis. Most of Europe, except the southeast. Annual.
- Lapsana communis subsp. adenophora (Boiss.) Rech.f. Southeast Europe.
- Lapsana communis subsp. alpina (Boiss. & Balansa) P.D.Sell. Crimea.
- Lapsana communis subsp. grandiflora (M. Bieb.) P.D.Sell. Southwest Asia.
- Lapsana communis subsp. intermedia (M. Bieb.) Hayek. Southwest Asia, southeast Europe. Perennial.
- Lapsana communis subsp. pisidica (Boiss. & Heldr.) Rech.f. Greece.
In the past, a number of other species were included in the genus; these species are now treated in the genera Crepis and Lapsanastrum.[5][6]
## Cultivation and uses
The young leaves are edible, and can be used in salads or cooked like spinach.[7] The scientific name comes from Lapsane, an edible herb described by Marcus Terentius Varro of ancient Rome. The English name 'Nipplewort' derives from its closed flower buds, which resemble nipples. Because of its resemblance to nipples, under the doctrine of signatures it was once used as treatment for breast ulcers.[8]
Away from its native area, Lapsana communis is naturalised, and sometimes considered an invasive species, in many areas around the world, including Australia, Chile, New Zealand, and most of North America.[9][10][11][12] | https://www.wikidoc.org/index.php/Lapsana | |
4b44db38cffce44c434ee2d449f14ed0c3457f10 | wikidoc | Laugher | Laugher
A laugher is a slang term for one of several types of drugs, usually euphorics or stimulants, that have a tendency to make the user laugh easily and hysterically while under its influence. Examples of laughers include cannabis (in small amounts), ecstasy and speed.
Other categories into which drugs may fall include uppers, downers, screamers and psychedelics.
Laughers are not always stimulants. When under the influence of certain sedative drugs such as marijuana or hashish, the user can get the "giggles" and can laugh for no apparent reason for long periods of time. When taken in small doses, the psilocybin mushroom can cause euphoria and make the user giggle and laugh. | Laugher
A laugher is a slang term for one of several types of drugs, usually euphorics or stimulants, that have a tendency to make the user laugh easily and hysterically while under its influence. Examples of laughers include cannabis (in small amounts), ecstasy and speed.
Other categories into which drugs may fall include uppers, downers, screamers and psychedelics.
Laughers are not always stimulants. When under the influence of certain sedative drugs such as marijuana or hashish, the user can get the "giggles" and can laugh for no apparent reason for long periods of time. When taken in small doses, the psilocybin mushroom can cause euphoria and make the user giggle and laugh. | https://www.wikidoc.org/index.php/Laugher | |
cb8e8a607e3446ea1013ca4680e7a722c37f3d55 | wikidoc | Lettuce | Lettuce
The Lettuce (Lactuca sativa) is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold and raw, in salads, hamburgers, tacos, and many other dishes. In some places, including China, lettuce is typically eaten cooked and use of the stem is as important as use of the leaf. Both the English name and the Latin name of the genus are ultimately derived from lac, the Latin word for “milk”, referring to the plant’s milky juice. Mild in flavour, it has been described over the centuries as a cooling counterbalance to other ingredients in a salad.
The lettuce plant has a short stem initially (a rosette growth habit), but when it blooms the stem lengthens and branches, and it produces many flower heads that look like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is harvested before it bolts. Lettuce is used as a food plant by the larvae of some Lepidoptera.
# Cultivars
There are six commonly recognised Cultivar Groups of lettuce which are ordered here by head formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf shape and colour, as well as extended field and shelf life, within each of these Cultivar Groups:
- Butterhead, also called Boston or Bibb, forms loose heads; it has a buttery texture. Butterhead cultivars are most popular in Europe.
- Chinese lettuce types generally have long, sword-shaped, non-head-forming leaves, with a bitter and robust flavour unlike Western types, appropriate for use in stir-fried dishes and stews. Chinese lettuce cultivars are divided into “stem-use” types (called celtuce in English), and “leaf-use” types such as youmaicai (Template:Zh-cp) or shengcai (生菜).
- Crisphead, also called Iceberg, which form tight, dense heads that resemble cabbage. They are generally the mildest of the lettuces, valued more for their crunchy texture than for flavour. Cultivars of iceberg lettuce are the most familiar lettuces in the USA. The name Iceberg comes from the way the lettuce was transported in the US starting in the 1920s on train-wagons covered in crushed ice, making them look like icebergs.
- Looseleaf, with tender, delicate, and mildly flavoured leaves. This group comprises oak leaf and lollo rosso lettuces.
- Romaine, also called Cos, is a head-forming type with elongated leaves.
- Summer Crisp, also called Batavian, which form moderately dense heads with a crunchy texture; this type is intermediate between iceberg and looseleaf types.
Some lettuces (especially iceberg) have been specifically bred to remove the bitterness from their leaves. These lettuces have a high water content with very little nutrient value. The more bitter lettuces and the ones with pigmented leaves contain antioxidants.
- Some lettuce cultivars
Some lettuce cultivars
- A Romaine lettuce
A Romaine lettuce
- Chemical compunds which occur in lettuce: 1: α-Lactucerol (=Taraxasterol); 2: β-Lactucerol (=Lactucon, Lactucerin); 3: Lactucin; 4: Lactucopicrin.
Chemical compunds which occur in lettuce:1: α-Lactucerol (=Taraxasterol); 2: β-Lactucerol (=Lactucon, Lactucerin); 3: Lactucin; 4: Lactucopicrin.
- More lettuce cultivars
More lettuce cultivars
# Breeding
L. sativa can easily be bred with closely related species in Lactuca such as L. serriola, L. saligna, and L. virosa, and breeding programs for cultivated lettuce have included those species to broaden the available gene pool. Starting in the 1990s, breeding programs began to include more distantly related species such as L. tatarica.
# Facts and figures
- Lactucarium (or “Lettuce Opium”) is a mild opiate-like substance that is contained in all types of lettuce. Both the Romans and Egyptians took advantage of this property eating lettuce at the end of a meal to induce sleep.
- Lettuce is a fat free, low calorie and saturated fat free food. It is a valuable source of vitamin A and folic acid
- The largest lettuce head weighed 11 kg (25 lb), of the Salad Bowl cultivar, grown by Colin Bowcock of Willaston, England, in 1974.
- In the United States, 95% of all head lettuce is grown in California and Arizona.
- The Yazidi consider eating lettuce taboo.
# History
The lettuce that we see today actually started out as a weed around the Mediterranean basin. Served in dishes for more than 4500 years, lettuce has certainly made its mark in history- as seen from tomb paintings in Egypt to the depiction of many different varieties in ancient Greek relics. Christopher Columbus introduced lettuce to the new world.
# Notes
- ↑ Simpson, D.P. (1979). Cassell's Latin Dictionary (5 ed.). London: Cassell Ltd. p. 883. ISBN 0-304-52257-0..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}
- ↑ Grigson, Jane (1978). The Vegetable Book. London: Penguin. pp. p. 312-14. ISBN 0-14-046-352-6.CS1 maint: Extra text (link)
- ↑ Wim J. M. Koopman, Eli Guetta, Clemens C. M. van de Wiel, Ben Vosman and Ronald G. van den Berg (1998). "Phylogenetic relationships among Lactuca (Asteraceae) species and related genera based on ITS-1 DNA sequences". American Journal of Botany. pp. 1517–1530.CS1 maint: Multiple names: authors list (link)
"Lettuce - Lactuca sativa - Daisy family". Hamilton, Dave (2005).
- ↑ "Lettuce:Food Facts & Trivia". Retrieved 2007-11-02. | Lettuce
Template:FixBunching
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Template:FixBunching
The Lettuce (Lactuca sativa) is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. In many countries, it is typically eaten cold and raw, in salads, hamburgers, tacos, and many other dishes. In some places, including China, lettuce is typically eaten cooked and use of the stem is as important as use of the leaf. Both the English name and the Latin name of the genus are ultimately derived from lac, the Latin word for “milk”,[1] referring to the plant’s milky juice. Mild in flavour, it has been described over the centuries as a cooling counterbalance to other ingredients in a salad.[2]
The lettuce plant has a short stem initially (a rosette growth habit), but when it blooms the stem lengthens and branches, and it produces many flower heads that look like those of dandelions, but smaller. This is called bolting. When grown to eat, lettuce is harvested before it bolts. Lettuce is used as a food plant by the larvae of some Lepidoptera.
# Cultivars
There are six commonly recognised Cultivar Groups of lettuce which are ordered here by head formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf shape and colour, as well as extended field and shelf life, within each of these Cultivar Groups:
- Butterhead, also called Boston or Bibb, forms loose heads; it has a buttery texture. Butterhead cultivars are most popular in Europe.
- Chinese lettuce types generally have long, sword-shaped, non-head-forming leaves, with a bitter and robust flavour unlike Western types, appropriate for use in stir-fried dishes and stews. Chinese lettuce cultivars are divided into “stem-use” types (called celtuce in English), and “leaf-use” types such as youmaicai (Template:Zh-cp) or shengcai (生菜).
- Crisphead, also called Iceberg, which form tight, dense heads that resemble cabbage. They are generally the mildest of the lettuces, valued more for their crunchy texture than for flavour. Cultivars of iceberg lettuce are the most familiar lettuces in the USA. The name Iceberg comes from the way the lettuce was transported in the US starting in the 1920s on train-wagons covered in crushed ice, making them look like icebergs.
- Looseleaf, with tender, delicate, and mildly flavoured leaves. This group comprises oak leaf and lollo rosso lettuces.
- Romaine, also called Cos, is a head-forming type with elongated leaves.
- Summer Crisp, also called Batavian, which form moderately dense heads with a crunchy texture; this type is intermediate between iceberg and looseleaf types.
Some lettuces (especially iceberg) have been specifically bred to remove the bitterness from their leaves. These lettuces have a high water content with very little nutrient value.[citation needed] The more bitter lettuces and the ones with pigmented leaves contain antioxidants.[citation needed]
- Some lettuce cultivars
Some lettuce cultivars
- A Romaine lettuce
A Romaine lettuce
- Chemical compunds which occur in lettuce: 1: α-Lactucerol (=Taraxasterol); 2: β-Lactucerol (=Lactucon, Lactucerin); 3: Lactucin; 4: Lactucopicrin.
Chemical compunds which occur in lettuce:1: α-Lactucerol (=Taraxasterol); 2: β-Lactucerol (=Lactucon, Lactucerin); 3: Lactucin; 4: Lactucopicrin.
- More lettuce cultivars
More lettuce cultivars
# Breeding
L. sativa can easily be bred with closely related species in Lactuca such as L. serriola, L. saligna, and L. virosa, and breeding programs for cultivated lettuce have included those species to broaden the available gene pool. Starting in the 1990s, breeding programs began to include more distantly related species such as L. tatarica.[3]
# Facts and figures
- Lactucarium (or “Lettuce Opium”) is a mild opiate-like substance that is contained in all types of lettuce. Both the Romans and Egyptians took advantage of this property eating lettuce at the end of a meal to induce sleep.[4]
- Lettuce is a fat free, low calorie and saturated fat free food. It is a valuable source of vitamin A and folic acid
- The largest lettuce head weighed 11 kg (25 lb), of the Salad Bowl cultivar, grown by Colin Bowcock of Willaston, England, in 1974.
- In the United States, 95% of all head lettuce is grown in California and Arizona.
- The Yazidi consider eating lettuce taboo.
# History
The lettuce that we see today actually started out as a weed around the Mediterranean basin. Served in dishes for more than 4500 years, lettuce has certainly made its mark in history- as seen from tomb paintings in Egypt to the depiction of many different varieties in ancient Greek relics. Christopher Columbus introduced lettuce to the new world.[5]
# Notes
- ↑ Simpson, D.P. (1979). Cassell's Latin Dictionary (5 ed.). London: Cassell Ltd. p. 883. ISBN 0-304-52257-0..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}
- ↑ Grigson, Jane (1978). The Vegetable Book. London: Penguin. pp. p. 312-14. ISBN 0-14-046-352-6.CS1 maint: Extra text (link)
- ↑ Wim J. M. Koopman, Eli Guetta, Clemens C. M. van de Wiel, Ben Vosman and Ronald G. van den Berg (1998). "Phylogenetic relationships among Lactuca (Asteraceae) species and related genera based on ITS-1 DNA sequences". American Journal of Botany. pp. 1517–1530.CS1 maint: Multiple names: authors list (link)
- ↑
"Lettuce - Lactuca sativa - Daisy family". Hamilton, Dave (2005).
- ↑ "Lettuce:Food Facts & Trivia". Retrieved 2007-11-02. | https://www.wikidoc.org/index.php/Lettuce | |
e15d1ce440c077afcd41c8b4f275b0643a379582 | wikidoc | Levulan | Levulan
Levulan photodynamic therapy is a treatment method for certain skin conditions developed by Dusa Pharmaceuticals. The active ingredient is δ-aminolevulinic acid (ALA). Food and Drug Administration (FDA) approval for actinic keratosis was received in December 1999; it is also prescribed against acne but this is an off-label use, which means it is not approved by the FDA.
A 20% solution of ALA is applied to the lesions, and after 14–18 hours wait the skin is irradiated with blue light for 15 minutes. This generates an active form of oxygen in the skin that kills cells and bacteria. The treated areas are sensitive to light, and patients must protect themselves against bright sunshine for two or three days after treatment. Patients must stop using topical acne medicine and avoid steam rooms, hot showers, and generally protect the skin in every way possible for up to one week after treatment.
Clinical trials indicate an 80% success rate for face lesions and a 50% success rate for scalp lesions after a 12 week course of treatment. | Levulan
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Levulan photodynamic therapy is a treatment method for certain skin conditions developed by Dusa Pharmaceuticals. The active ingredient is δ-aminolevulinic acid (ALA). Food and Drug Administration (FDA) approval for actinic keratosis was received in December 1999; it is also prescribed against acne but this is an off-label use, which means it is not approved by the FDA.
A 20% solution of ALA is applied to the lesions, and after 14–18 hours wait the skin is irradiated with blue light for 15 minutes. This generates an active form of oxygen in the skin that kills cells and bacteria. The treated areas are sensitive to light, and patients must protect themselves against bright sunshine for two or three days after treatment. Patients must stop using topical acne medicine and avoid steam rooms, hot showers, and generally protect the skin in every way possible for up to one week after treatment.
Clinical trials indicate an 80% success rate for face lesions and a 50% success rate for scalp lesions after a 12 week course of treatment. | https://www.wikidoc.org/index.php/Levulan | |
4ad6ef8908dcbe991f6f8810f0ab1e0aaa536ab5 | wikidoc | Lighter | Lighter
A lighter is a portable device used to create a flame. It consists of a metal or plastic container filled with lighter fluid (usually naphtha or liquid butane under pressure), as well as a means of ignition and some provision for extinguishing the flame, either by depriving it of air or of fuel.
Lighters using naphtha have a wick which is immersed in the fluid and becomes saturated. This type usually has a fiber packing material which absorbs the liquid to keep it from leaking. They also must have an enclosed top to prevent the volatile liquid from evaporating, and to conveniently extinguish the flame. Butane lighters have a valved orifice that meters the butane as it escapes as a gas.
A spark is created by striking metal against a flint, or by pressing a button that compresses a piezoelectric crystal, generating a voltaic arc (see Piezo ignition). In naphtha lighters the liquid is volatile enough that flammable gas is present as soon as the top of the lighter is opened. Butane lighters combine the striking action with the opening of the valve to release gas. The spark ignites the flammable gas causing a flame to come out of the lighter which continues until either the top is closed (naphtha type), or the valve is released (butane type).
A metal enclosure with air holes generally surrounds the flame, and is designed to allow mixing of fuel and air while making the lighter less sensitive to wind. The high energy jet in butane lighters allows mixing to be accomplished by using Bernoulli's principle, so that the air hole(s) in this type tend to be much smaller and farther from the flame.
# History
The first lighter, Döbereiner's lamp, was invented by Johann Wolfgang Döbereiner in 1823. It stayed in production until 1880.The first "match" was created in 1805. The first friction match, which can be ignited on virtually any surface (i.e. fabric) was created in 1827, 4 years after the lighter.
# Lighter Re-Distribution
It is common place for a cigarette lighter to change ownership many times in its lifetime. According to a recent study at TVU in Reading an average disposable lighter will make its way in to the pockets of 7 different smokers during its time and only 1 out of 45 lighters ever survive until they become un-useable.
# Car cigarette lighters
Most cars are equipped with an electric cigarette lighter plug that fits in the socket. Its internal heating element becomes glowing orange hot in seconds when the device is activated, and is capable of lighting cigarettes, cigars and tinder (among other things).
The lighter's socket doubles as a 12 volt power outlet that can be used to power many small electrical devices. In some newer cars, due to the decreasing popularity of smoking in some countries and the popularity of in-car electronics, the lighter plug has been omitted while leaving the socket behind as a power source.
# In Pop Culture
During slow songs at live concerts, particularly power ballads, concert goers often wave lighters in the air. This tradition is being at least partly superseded by the waving of mobile phones, both for safety reasons, and because mobile phone users are becoming more common than smokers.
## History
According to an interview by Matthew Alice, the use of lighters in concerts started due to the influence of several sources, making it difficult to trace. First, there is the theory that the practice simply started at a Neil Diamond concert of 1972 or a Bob Dylan concert at 1974, because the audience had lighters available. Another theory is that the gesture is symbolic of songs with flames mentioned, such as the Doors' "Light My Fire." Another theory is that this practice came out of a performance during Woodstock where candles (rather than lighters) were held aloft, and evolved from this. | Lighter
A lighter is a portable device used to create a flame. It consists of a metal or plastic container filled with lighter fluid (usually naphtha or liquid butane under pressure), as well as a means of ignition and some provision for extinguishing the flame, either by depriving it of air or of fuel.
Lighters using naphtha have a wick which is immersed in the fluid and becomes saturated. This type usually has a fiber packing material which absorbs the liquid to keep it from leaking. They also must have an enclosed top to prevent the volatile liquid from evaporating, and to conveniently extinguish the flame. Butane lighters have a valved orifice that meters the butane as it escapes as a gas.
A spark is created by striking metal against a flint, or by pressing a button that compresses a piezoelectric crystal, generating a voltaic arc (see Piezo ignition). In naphtha lighters the liquid is volatile enough that flammable gas is present as soon as the top of the lighter is opened. Butane lighters combine the striking action with the opening of the valve to release gas. The spark ignites the flammable gas causing a flame to come out of the lighter which continues until either the top is closed (naphtha type), or the valve is released (butane type).
A metal enclosure with air holes generally surrounds the flame, and is designed to allow mixing of fuel and air while making the lighter less sensitive to wind. The high energy jet in butane lighters allows mixing to be accomplished by using Bernoulli's principle, so that the air hole(s) in this type tend to be much smaller and farther from the flame.
# History
The first lighter, Döbereiner's lamp, was invented by Johann Wolfgang Döbereiner in 1823. It stayed in production until 1880.The first "match" was created in 1805. The first friction match, which can be ignited on virtually any surface (i.e. fabric) was created in 1827, 4 years after the lighter.[1]
# Lighter Re-Distribution
It is common place for a cigarette lighter to change ownership many times in its lifetime. According to a recent study at TVU in Reading an average disposable lighter will make its way in to the pockets of 7 different smokers during its time and only 1 out of 45 lighters ever survive until they become un-useable.[citation needed]
# Car cigarette lighters
Template:Seealso
Most cars are equipped with an electric cigarette lighter plug that fits in the socket. Its internal heating element becomes glowing orange hot in seconds when the device is activated, and is capable of lighting cigarettes, cigars and tinder (among other things).
The lighter's socket doubles as a 12 volt power outlet that can be used to power many small electrical devices. In some newer cars, due to the decreasing popularity of smoking in some countries and the popularity of in-car electronics, the lighter plug has been omitted while leaving the socket behind as a power source.
# In Pop Culture
During slow songs at live concerts, particularly power ballads, concert goers often wave lighters in the air. This tradition is being at least partly superseded by the waving of mobile phones, both for safety reasons, and because mobile phone users are becoming more common than smokers.[citation needed]
## History
According to an interview by Matthew Alice, the use of lighters in concerts started due to the influence of several sources, making it difficult to trace. First, there is the theory that the practice simply started at a Neil Diamond concert of 1972 or a Bob Dylan concert at 1974, because the audience had lighters available. Another theory is that the gesture is symbolic of songs with flames mentioned, such as the Doors' "Light My Fire." Another theory is that this practice came out of a performance during Woodstock where candles (rather than lighters) were held aloft, and evolved from this. [1]
Template:Sect-stub | https://www.wikidoc.org/index.php/Lighter | |
3172ba2fae05758d4dcf0f0973299eb20465c921 | wikidoc | Lignite | Lignite
Lignite, often referred to as brown coal, is the lowest rank of coal and used almost exclusively as fuel for steam-electric power generation.
It is brownish-black and has a high inherent moisture content, sometimes as high as 66 percent, and very high ash content compared with bituminous coal. It is also a heterogeneous mixture of compounds for which no single structural formula will suffice.
The heat content of lignite ranges from 10 to 20 MJ/kg (9 to 17 million Btu per short ton) on a moist, mineral-matter-free basis. The heat content of lignite consumed in the United States averages 13 million Btu/ton (15 MJ/kg), on the as-received basis (i.e., containing both inherent moisture and mineral matter).
When reacted with quaternary amine, amine treated lignite (ATL) forms. ATL is used in oil well drilling fluids to reduce fluid loss.
Because of its low energy density, brown coal is inefficient to transport and is not traded extensively on the world market compared with higher coal grades. It is often burned in power stations constructed very close to any mines, such as in Australia's Latrobe Valley. Carbon dioxide emissions from brown coal fired plants are generally much higher than for comparable black coal plants. The continued operation of brown coal plants, particularly in combination with strip mining and in the absence of emissions-avoiding technology like carbon sequestration, is politically contentious.
Lignite mined in millions of metric tons: | Lignite
Lignite, often referred to as brown coal, is the lowest rank of coal and used almost exclusively as fuel for steam-electric power generation.
It is brownish-black and has a high inherent moisture content, sometimes as high as 66 percent, and very high ash content compared with bituminous coal. It is also a heterogeneous mixture of compounds for which no single structural formula will suffice.
The heat content of lignite ranges from 10 to 20 MJ/kg (9 to 17 million Btu per short ton) on a moist, mineral-matter-free basis. The heat content of lignite consumed in the United States averages 13 million Btu/ton (15 MJ/kg), on the as-received basis (i.e., containing both inherent moisture and mineral matter).
When reacted with quaternary amine, amine treated lignite (ATL) forms. ATL is used in oil well drilling fluids to reduce fluid loss.
Because of its low energy density, brown coal is inefficient to transport and is not traded extensively on the world market compared with higher coal grades. It is often burned in power stations constructed very close to any mines, such as in Australia's Latrobe Valley. Carbon dioxide emissions from brown coal fired plants are generally much higher than for comparable black coal plants. The continued operation of brown coal plants, particularly in combination with strip mining and in the absence of emissions-avoiding technology like carbon sequestration, is politically contentious.[1][2]
Lignite mined in millions of metric tons[citation needed]: | https://www.wikidoc.org/index.php/Lignite | |
ed94f5265accbca4ba80d9307f6eef2bc1b77dce | wikidoc | Lingula | Lingula
Lingula is Latin for "little tongue". It can stand for:
- Lingula (genus) a brachiopod genus of the family Lingulidae, which is among the few brachiopods surviving today but also known from fossils over 50 million years old.
- In anatomy:
the Lingula of left lung is one of the segments of the left lung with a tongue-shape
The Sphenoidal lingula is part of the sphenoid bone
The Lingula of mandible, a ridge on the medial aspect of the body of the mandible, just anterior to the mandibular foramen
the Lingula of cerebellum
- the Lingula of left lung is one of the segments of the left lung with a tongue-shape
- The Sphenoidal lingula is part of the sphenoid bone
- The Lingula of mandible, a ridge on the medial aspect of the body of the mandible, just anterior to the mandibular foramen
- the Lingula of cerebellum | Lingula
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Lingula is Latin for "little tongue". It can stand for:
- Lingula (genus) a brachiopod genus of the family Lingulidae, which is among the few brachiopods surviving today but also known from fossils over 50 million years old.
- In anatomy:
the Lingula of left lung is one of the segments of the left lung with a tongue-shape
The Sphenoidal lingula is part of the sphenoid bone
The Lingula of mandible, a ridge on the medial aspect of the body of the mandible, just anterior to the mandibular foramen
the Lingula of cerebellum
- the Lingula of left lung is one of the segments of the left lung with a tongue-shape
- The Sphenoidal lingula is part of the sphenoid bone
- The Lingula of mandible, a ridge on the medial aspect of the body of the mandible, just anterior to the mandibular foramen
- the Lingula of cerebellum | https://www.wikidoc.org/index.php/Lingula | |
9af0eeb207918c6d5fee39df237b01ba597e310c | wikidoc | Lingzhi | Lingzhi
Língzhī (traditional Chinese: 靈芝; simplified Chinese: 灵芝; Japanese: reishi; Korean: yeongji, hangul: 영지) is the name for one form of the mushroom Ganoderma lucidum, and its close relative Ganoderma tsugae, which grows in the northern Eastern Hemlock forests. These two species of bracket fungus have a worldwide distribution in both tropical and temperate geographical regions, including North and South America, Africa, Europe, and Asia, growing as a parasite or saprotroph on a wide variety of trees. Ganoderma lucidum enjoys special veneration in Asia, where it has been used in traditional Chinese medicine as a herbal medicine for more than 4,000 years, making it one of the oldest mushrooms known to have been used in medicine. Similar species of Ganoderma have been found growing in the Amazon, according to mycologist Christopher Hobbs.
The word lingzhi, in Chinese, means "herb of spiritual potency" and has also been described as "mushroom of immortality". Because of its presumed health benefits and apparent absence of side-effects, it has attained a reputation in the East as the ultimate herbal substance. Lingzhi has now been added to the American Herbal Pharmacopoeia and Therapeutic Compendium.
# Taxonomy and naming
The name Ganoderma is derived from the Greek ganos/γανος "brightness, sheen", hence "shining" and derma/δερμα "skin", while the specific epithet lucidum in Latin for "shining" and tsugae refers to being of the Hemlock (Tsuga). Another Japanese name is mannentake, meaning "10 000 year mushroom".
There are multiple species of lingzhi, scientifically known to be within the Ganoderma lucidum species complex and mycologists are still researching the differences between species within this complex of species.
# Description
Lingzhi is a polypore mushroom that is soft (when fresh), corky, and flat, with a conspicuous red-varnished, kidney-shaped cap and, depending on specimen age, white to dull brown pores underneath. It lacks gills on its underside and releases its spores through fine pores, leading to its morphological classification as a polypore.
## Varieties
Ganoderma lucidum generally occurs in two growth forms, one, found in North America, is sessile and rather large with only a small or no stalk, while the other is smaller and has a long, narrow stalk, and is found mainly in the tropics. However, many growth forms exist that are intermediate to the two types, or even exhibit very unusual morphologies, raising the possibility that they are separate species. Environmental conditions also play a substantial role in the different morphological characteristics lingzhi can exhibit. For example, elevated carbon dioxide levels result in stem elongation in lingzhi. Other forms show "antlers', without a cap and these may be affected by carbon dioxide levels as well.
According to The Chinese Herbal Materia Medica (本草綱目), lingzhi may be classified into six categories according to their shapes and colors, each of which is believed to nourish a different part of the body.
- Red - heart
- Purple - joints
- Green - liver
- White - lungs and skin
- Yellow - spleen
- Black - kidneys and brain
# Biochemistry
Ganoderma lucidum is the only known source of a group of triterpenes, known as ganoderic acids, which have a molecular structure similar to steroid hormones. It is a source of biologically active polysaccharides with presumed medicinal properties, and it also contains:
- ergosterol
- coumarin
- mannitol
- lactones
- alkaloids
- unsaturated fatty acids
- vitamins and minerals.
Unlike many other mushrooms, which have up to 90% water content, fresh Lingzhi only contains about 75% water.
# Habitat
In nature, Lingzhi grows at the base and stumps of deciduous trees, especially maple (National Audubon Society; Field guide to Mushrooms,1993). Only two or three out of 10,000 such aged trees will have Lingzhi growth, and therefore its wild form is generally rare. Today, Lingzhi is effectively cultivated both indoors under sterile conditions and outdoors on either logs or woodchip beds.
# History
The Shen Nong's Herbal Classic, a 2000-year old medicinal Chinese book considered today as the oldest book on oriental herbal medicine, classifies 365 species of roots, grass, woods, furs, animals and stones into three categories of herbal medicine:
- The first category, called "superior", includes herbs effective for multiple diseases and are mostly responsible for maintaining and restoring the body balance. They have almost no unfavorable side-effects.
- The second category comprises tonics and boosters, for which their consumption must not be prolonged.
- The third category must be taken, usually in small doses, and for the treatment of specific ailments only.
Lingzhi ranked number one of the superior medicines, and was therefore the most exalted medicine in ancient times.
# Current usage
Lingzhi can be found for sale in many Asian markets as well as Western health shops. Extracts of 'lingzhi,' which may also be called 'reishi' are also available. In general, a hot water extract is best at concentrating the polysaccharides in lingzhi and alcohol extracts are best at concentrating the triterpenoids in lingzhi but an extract can also be made with a blend of both extracts.
## Medicinal uses
Lingzhi may possess some anti-tumor, immunomodulatory and immunotherapeutic activities, supported by some studies on polysaccharides, terpenes, and other bioactive compounds isolated from fruiting bodies and mycelia of this fungus (reviewed by R. R. Paterson). However, the efficacy of these compounds in the treatment of cancer has not yet been shown in clinical trials. Moreover, as with any herb, variation between preparations and potential negative side effects cannot be ruled out. It is understood as adaptogenic, anti-allergenic and anti-hypertensive due to the presence of triterpenes. Apart from these properties, lingzhi has been found to be anti-inflammatory, antiviral, anti-parasitic, anti-fungal, antidiabetic, anti-hypotensive, and protective of the liver. It has also been found to inhibit platelet aggregation, and to lower blood pressure, cholesterol and blood sugar.
Because of these properties, lingzhi has been regarded as blood pressure stabilizer, antioxidant, analgesic, a kidney and nerve tonic. It has been used in bronchitis prevention and in cardiovascular treatment, and in the treatment of high triglycerides, high blood pressure, hepatitis, allergies, chemotherapy support, HIV support, and even for fatigue and altitude sickness.
Some peer-reviewed studies indicate that ganoderic acid has some protective effects against liver injury by viruses and other toxic agents in mice, suggesting a potential benefit of this compound in the treatment of liver diseases in humans.
Although the experiences in fighting cancer are more inconsistent, the extract has been claimed to be effective in regressing tumors. The results depend on the type of cancer and the severity of the condition. It is usually recommended that it be used in combination with other prescribed medical treatments and as part of a fu zheng formula with a variety of supporting herbs. The Ganoderma extract has been employed to help substantially reduce or eliminate the side-effects of radio- and chemotherapies if it is taken before, during and after the treatments. It has been found clinically to reduce side-effects like hair loss, nausea, vomiting, stomatitis, sore throat, loss of appetite and insomnia.
## Preparation
Because mushrooms contain chitin which locks up medicinal components, preparations of lingzhi are unlikely to be medicinally active unless there has been a prolonged water extraction. Simply tincturing the mushroom in ethanol or powdering it and encapsulating it makes preparations that are essentially inert and may account for some of the inconsistency in research results. Additionally, mushrooms traditionally incorporate or transform constituents from their host trees and mycelial fractions grown in sawdust or other substrate may differ appreciably from the whole fungus.
Lingzhi is traditionally prepared by simmering in water. Thinly sliced or pulverized lingzhi (either fresh or dried) is added to a pot of boiling water, the water is then brought to a simmer, and the pot is covered; the lingzhi is then simmered for two hours. The resulting liquid should be fairly bitter in taste, with the more active red lingzhi more bitter than the black. The process may be repeated. Alternatively, it can be used as an ingredient in a formula decoction or used to make an extract (in liquid, capsule, or powder form). The more active red forms of lingzhi are far too bitter to be consumed in a soup, as long cooked shitake mushrooms might be.
## Side effects
It has been shown in some studies that long term use of Lingzhi (usually four months or so) can result in some mild side effects, including dryness of the nasal passages, mouth and throat, as well as stomach upset and nosebleed. However, these effects were avoided by discontinuing use of the mushroom for one month after taking it for four months, and taking it again for four months and so on.
# Modern scientific studies
Numerous studies of lingzhi, mainly in China, Korea, Japan and the United States, have shown its effectiveness in the treatment of a very wide range of diseases and symptoms. But the studies have not given any explanation of exactly how lingzhi has so many diverse effects, because none of the known active components taken alone have produced results as powerful as the intake of lingzhi itself, suggesting synergy is important. For example, reports of lingzhi's effect on stamina, appetite, and other human conditions are largely anecdotal and haven't been studied scientifically. It is perhaps more comprehensible at this time to explain lingzhi's "miraculous powers" from the traditional Chinese medicine point of view.
In the West, scientists have traditionally separated and classified each disease meticulously, and have specialized in each of them to such a degree that it seems as if each disease is autonomous and standing alone. Oriental medicine, resulting from knowledge accumulated through 4,000 years of human observation, asserts that health can be maintained by sustaining the proper balance within the body and that diseases can be cured by restoring this balance through nutrition, including medicinal herbs, exercise and mental peace. Traditional oriental medicine believes that a disease is but the mere tip of an iceberg, the result of the underlying imbalance of the body which must be restored.
Observations have shown that lingzhi generally has only slight side effects and can be consumed in high doses, in parallel with other medications. Its main properties are adaptogenic which mean that it is nontoxic, it works in a generalized manner on the hypothalamic-pituitary-adrenal axis and the neuroendocrine system. Its actions are alterative, enhance the immune system and lessen nervous tension. These properties are conducive to normalizing and balancing the body (homeostasis and allostasis), and as a result, lingzhi is able to help the body cure a multitude of disease states from within.
Lingzhi has been found to strengthen the respiratory system and to have a healing effect on the lungs, and is particularly beneficial for individuals with asthma, cough and other respiratory complaints. At least one population study conducted in the 1970s confirms this claim. When more than 2,000 Chinese with chronic bronchitis took lingzhi syrup, 60 to 90% felt better within two weeks and reported an improved appetite, according to an article entitled, Medicinal Mushrooms, written by Christopher Hobbs, and published in Herbs for Health, Jan/February 97.
In Japan, after daily injections in mice with cancer it was reported that tumors in 50% of the animals had completely regressed within 10 days. (Ikekawa et al,1968;Japanese Journal of Cancer Research; 59: 155-157) The host-dependent anti-tumor activity has been subsequently confirmed to be from the polysaccharide fractions of Ganoderma by Sasaki et al.. Multiple similar studies subsequently confirms this observation and anti-tumor efficacy of Ganoderma has been demonstrated from various species, at different stages of growth and using different solvents for extraction and different routes of administration. Anti-tumor activity has been demonstrated in vitro as well as in syngeneic tumor systems in animals. However, no human trials of Ganoderma against cancer in peer reviewed journals nor any controlled clinical trials in humans have yet been conducted or published.
There has been research showing lingzhi an effective supplement during chemotherapy or radiotherapy to reduce side-effects such as fatigue, loss of appetite, hair loss, bone marrow suppression and risk of infection. Ganodermas was shown effective against fatigue , hair loss , and bone marrow suppression . There is similar clinical evidence for other glucan BRMs applied in the setting of cancer chemotherapy or radiotherapy lending further support to the supplementation of Ganoderma in combination with cytotoxic cancer therapies. The recommended dose should be in the range of five to ten grams of fruiting body or equivalent per day .
In an animal model, Ganoderma has been demonstrated to effectively prevent cancer metastasis , and these results are comparable to those of Lentinan from shitake mushrooms While only anecdotal or clinical data exists indicating ganoderma supplementation may enhance survival of human cancer patients, this survival advantage has been demonstrated for a number of comparable glucan BRMs like lentinan. Lentinan use in advanced gastric cancer demonstrated a significant life span prolongation advantage at 1, 2, 3 and 4 years in a randomized control trial . Lentinan is however injected. More appropriate for comparison to Ganoderma is perhaps PSK or PSP, which are orally administered. Mitomi et al. found significantly improved survival and disease-free survival (P=0.013) in colorectal cancer given PSK supplementation over three years when compared to control in a multi-center randomized controlled trials. | Lingzhi
Template:Mycomorphbox
Língzhī (traditional Chinese: 靈芝; simplified Chinese: 灵芝; Japanese: reishi; Korean: yeongji, hangul: 영지) is the name for one form of the mushroom Ganoderma lucidum, and its close relative Ganoderma tsugae, which grows in the northern Eastern Hemlock forests. These two species of bracket fungus have a worldwide distribution in both tropical and temperate geographical regions, including North and South America, Africa, Europe, and Asia, growing as a parasite or saprotroph on a wide variety of trees.[1] Ganoderma lucidum enjoys special veneration in Asia, where it has been used in traditional Chinese medicine as a herbal medicine for more than 4,000 years, making it one of the oldest mushrooms known to have been used in medicine. Similar species of Ganoderma have been found growing in the Amazon, according to mycologist Christopher Hobbs. [2]
The word lingzhi, in Chinese, means "herb of spiritual potency" and has also been described as "mushroom of immortality".[1] Because of its presumed health benefits and apparent absence of side-effects, it has attained a reputation in the East as the ultimate herbal substance. Lingzhi has now been added to the American Herbal Pharmacopoeia and Therapeutic Compendium.
# Taxonomy and naming
The name Ganoderma is derived from the Greek ganos/γανος "brightness, sheen", hence "shining" and derma/δερμα "skin",[3] while the specific epithet lucidum in Latin for "shining" and tsugae refers to being of the Hemlock (Tsuga). Another Japanese name is mannentake, meaning "10 000 year mushroom".
There are multiple species of lingzhi, scientifically known to be within the Ganoderma lucidum species complex and mycologists are still researching the differences between species within this complex of species.[4]
# Description
Lingzhi is a polypore mushroom that is soft (when fresh), corky, and flat, with a conspicuous red-varnished, kidney-shaped cap and, depending on specimen age, white to dull brown pores underneath.[1] It lacks gills on its underside and releases its spores through fine pores, leading to its morphological classification as a polypore.
## Varieties
Ganoderma lucidum generally occurs in two growth forms, one, found in North America, is sessile and rather large with only a small or no stalk, while the other is smaller and has a long, narrow stalk, and is found mainly in the tropics. However, many growth forms exist that are intermediate to the two types, or even exhibit very unusual morphologies,[1] raising the possibility that they are separate species. Environmental conditions also play a substantial role in the different morphological characteristics lingzhi can exhibit. For example, elevated carbon dioxide levels result in stem elongation in lingzhi. Other forms show "antlers', without a cap and these may be affected by carbon dioxide levels as well.
According to The Chinese Herbal Materia Medica (本草綱目), lingzhi may be classified into six categories according to their shapes and colors, each of which is believed to nourish a different part of the body.
- Red - heart
- Purple - joints
- Green - liver
- White - lungs and skin
- Yellow - spleen
- Black - kidneys and brain
# Biochemistry
Ganoderma lucidum is the only known source of a group of triterpenes, known as ganoderic acids, which have a molecular structure similar to steroid hormones. It is a source of biologically active polysaccharides with presumed medicinal properties, and it also contains:
- ergosterol
- coumarin
- mannitol
- lactones
- alkaloids
- unsaturated fatty acids
- vitamins and minerals.
Unlike many other mushrooms, which have up to 90% water content, fresh Lingzhi only contains about 75% water.
# Habitat
In nature, Lingzhi grows at the base and stumps of deciduous trees, especially maple (National Audubon Society; Field guide to Mushrooms,1993). Only two or three out of 10,000 such aged trees will have Lingzhi growth, and therefore its wild form is generally rare. Today, Lingzhi is effectively cultivated both indoors under sterile conditions and outdoors on either logs or woodchip beds.
# History
The Shen Nong's Herbal Classic, a 2000-year old medicinal Chinese book considered today as the oldest book on oriental herbal medicine, classifies 365 species of roots, grass, woods, furs, animals and stones into three categories of herbal medicine:
- The first category, called "superior", includes herbs effective for multiple diseases and are mostly responsible for maintaining and restoring the body balance. They have almost no unfavorable side-effects.
- The second category comprises tonics and boosters, for which their consumption must not be prolonged.
- The third category must be taken, usually in small doses, and for the treatment of specific ailments only.
Lingzhi ranked number one of the superior medicines, and was therefore the most exalted medicine in ancient times.
# Current usage
Lingzhi can be found for sale in many Asian markets as well as Western health shops. Extracts of 'lingzhi,' which may also be called 'reishi' are also available. In general, a hot water extract is best at concentrating the polysaccharides in lingzhi and alcohol extracts are best at concentrating the triterpenoids in lingzhi but an extract can also be made with a blend of both extracts.
## Medicinal uses
Lingzhi may possess some anti-tumor, immunomodulatory and immunotherapeutic activities, supported by some studies on polysaccharides, terpenes, and other bioactive compounds isolated from fruiting bodies and mycelia of this fungus (reviewed by R. R. Paterson[5]). However, the efficacy of these compounds in the treatment of cancer has not yet been shown in clinical trials.[6] Moreover, as with any herb, variation between preparations and potential negative side effects cannot be ruled out. It is understood as adaptogenic, anti-allergenic and anti-hypertensive due to the presence of triterpenes. Apart from these properties, lingzhi has been found to be anti-inflammatory, antiviral, anti-parasitic, anti-fungal, antidiabetic, anti-hypotensive, and protective of the liver. It has also been found to inhibit platelet aggregation, and to lower blood pressure, cholesterol and blood sugar. [7][8][9]
Because of these properties, lingzhi has been regarded as blood pressure stabilizer, antioxidant, analgesic, a kidney and nerve tonic. It has been used in bronchitis prevention and in cardiovascular treatment, and in the treatment of high triglycerides, high blood pressure, hepatitis, allergies, chemotherapy support, HIV support, and even for fatigue and altitude sickness. [10][11][12]
Some peer-reviewed studies indicate that ganoderic acid has some protective effects against liver injury by viruses and other toxic agents in mice, suggesting a potential benefit of this compound in the treatment of liver diseases in humans.[13]
Although the experiences in fighting cancer are more inconsistent, the extract has been claimed to be effective in regressing tumors. The results depend on the type of cancer and the severity of the condition. It is usually recommended that it be used in combination with other prescribed medical treatments and as part of a fu zheng formula with a variety of supporting herbs. The Ganoderma extract has been employed to help substantially reduce or eliminate the side-effects of radio- and chemotherapies if it is taken before, during and after the treatments. It has been found clinically to reduce side-effects like hair loss, nausea, vomiting, stomatitis, sore throat, loss of appetite and insomnia.
## Preparation
Because mushrooms contain chitin which locks up medicinal components, preparations of lingzhi are unlikely to be medicinally active unless there has been a prolonged water extraction.[citation needed] Simply tincturing the mushroom in ethanol or powdering it and encapsulating it makes preparations that are essentially inert and may account for some of the inconsistency in research results. Additionally, mushrooms traditionally incorporate or transform constituents from their host trees and mycelial fractions grown in sawdust or other substrate may differ appreciably from the whole fungus.
Lingzhi is traditionally prepared by simmering in water. Thinly sliced or pulverized lingzhi (either fresh or dried) is added to a pot of boiling water, the water is then brought to a simmer, and the pot is covered; the lingzhi is then simmered for two hours. The resulting liquid should be fairly bitter in taste, with the more active red lingzhi more bitter than the black. The process may be repeated. Alternatively, it can be used as an ingredient in a formula decoction or used to make an extract (in liquid, capsule, or powder form). The more active red forms of lingzhi are far too bitter to be consumed in a soup, as long cooked shitake mushrooms might be.
## Side effects
It has been shown in some studies that long term use of Lingzhi (usually four months or so) can result in some mild side effects, including dryness of the nasal passages, mouth and throat, as well as stomach upset and nosebleed[citation needed]. However, these effects were avoided by discontinuing use of the mushroom for one month after taking it for four months, and taking it again for four months and so on.
# Modern scientific studies
Numerous studies of lingzhi, mainly in China[14][15], Korea[16], Japan[17] and the United States, have shown its effectiveness in the treatment of a very wide range of diseases and symptoms. [18] But the studies have not given any explanation of exactly how lingzhi has so many diverse effects, because none of the known active components taken alone have produced results as powerful as the intake of lingzhi itself, suggesting synergy is important. For example, reports of lingzhi's effect on stamina, appetite, and other human conditions are largely anecdotal and haven't been studied scientifically. It is perhaps more comprehensible at this time to explain lingzhi's "miraculous powers" from the traditional Chinese medicine point of view.
In the West, scientists have traditionally separated and classified each disease meticulously, and have specialized in each of them to such a degree that it seems as if each disease is autonomous and standing alone. Oriental medicine, resulting from knowledge accumulated through 4,000 years of human observation, asserts that health can be maintained by sustaining the proper balance within the body and that diseases can be cured by restoring this balance through nutrition, including medicinal herbs, exercise and mental peace. Traditional oriental medicine believes that a disease is but the mere tip of an iceberg, the result of the underlying imbalance of the body which must be restored.
Observations have shown that lingzhi generally has only slight side effects and can be consumed in high doses, in parallel with other medications. Its main properties are adaptogenic which mean that it is nontoxic, it works in a generalized manner on the hypothalamic-pituitary-adrenal axis and the neuroendocrine system. Its actions are alterative, enhance the immune system and lessen nervous tension. [19]These properties are conducive to normalizing and balancing the body (homeostasis and allostasis), and as a result, lingzhi is able to help the body cure a multitude of disease states from within.
Lingzhi has been found to strengthen the respiratory system and to have a healing effect on the lungs, and is particularly beneficial for individuals with asthma, cough and other respiratory complaints. At least one population study conducted in the 1970s confirms this claim. When more than 2,000 Chinese with chronic bronchitis took lingzhi syrup, 60 to 90% felt better within two weeks and reported an improved appetite, according to an article entitled, Medicinal Mushrooms, written by Christopher Hobbs, and published in Herbs for Health, Jan/February 97.
In Japan, after daily injections in mice with cancer it was reported that tumors in 50% of the animals had completely regressed within 10 days. (Ikekawa et al,1968;Japanese Journal of Cancer Research; 59: 155-157) The host-dependent anti-tumor activity has been subsequently confirmed to be from the polysaccharide fractions of Ganoderma by Sasaki et al.. [20]Multiple similar studies subsequently confirms this observation and anti-tumor efficacy of Ganoderma has been demonstrated from various species, at different stages of growth and using different solvents for extraction and different routes of administration. Anti-tumor activity has been demonstrated in vitro as well as in syngeneic tumor systems in animals. However, no human trials of Ganoderma against cancer in peer reviewed journals nor any controlled clinical trials in humans have yet been conducted or published.
There has been research showing lingzhi an effective supplement during chemotherapy or radiotherapy to reduce side-effects such as fatigue, loss of appetite, hair loss, bone marrow suppression and risk of infection. Ganodermas was shown effective against fatigue [21], hair loss [22], and bone marrow suppression [23]. There is similar clinical evidence for other glucan BRMs applied in the setting of cancer chemotherapy or radiotherapy [24] lending further support to the supplementation of Ganoderma in combination with cytotoxic cancer therapies. The recommended dose should be in the range of five to ten grams of fruiting body or equivalent per day [25].
In an animal model, Ganoderma has been demonstrated to effectively prevent cancer metastasis [26], and these results are comparable to those of Lentinan from shitake mushrooms [27] While only anecdotal or clinical data exists indicating ganoderma supplementation may enhance survival of human cancer patients, this survival advantage has been demonstrated for a number of comparable glucan BRMs like lentinan. Lentinan use in advanced gastric cancer demonstrated a significant life span prolongation advantage at 1, 2, 3 and 4 years in a randomized control trial [28]. Lentinan is however injected. More appropriate for comparison to Ganoderma is perhaps PSK or PSP, which are orally administered. Mitomi et al. [29] found significantly improved survival and disease-free survival (P=0.013) in colorectal cancer given PSK supplementation over three years when compared to control in a multi-center randomized controlled trials. | https://www.wikidoc.org/index.php/Lingzhi | |
bb72cf0868d78fe01d283b6e3ee86fc24ed607d1 | wikidoc | Lipoxin | Lipoxin
Lipoxins are a series of anti-inflamatory mediators. Lipoxins are short lived endogenously produced eicosanoids whose appearance in inflammation signals the resolution of inflammation. During the acute inflammatory process, the proinflammatory cytokines such as IFN-γ and IL-1β can induce the expression of anti-inflammatory mediators such as lipoxins (LXs) and IL-4, which promote the resolution phase of inflammation.
They are abbreviated as LX, an acronym for lipoxygenase (LO) interaction products.
Lipoxins are derived from arachidonic acid, an ω-6 fatty acid
An analogous class, the resolvins, is derived from EPA and DHA, ω-3 fatty acids.
At present two lipoxins have been identified; lipoxin A4 (LXA4) and lipoxin B4 (LXB4).
Lipoxins, as well as certain peptides, are high affinity (sub nanomolar) ligands for the lipoxin A4 receptor (ALXR), which was first identified based on sequence homology as the formyl peptide receptor like receptor (FPRL1). Lipoxin signaling through the ALXR inhibits chemotaxis, transmigration, superoxide generation and NF-kB activation.
Conversely, peptide signalling through the same receptor, in vitro, has been shown to stimulate chemotaxis of PMN and calcium mobilization. The peptides that have ALXR affinity tend to be signals for leukocyte migration and subsequent phagocytosis such as acute phase proteins, bacterial peptides, HIV envelope proteins and neurotoxic peptides.
Lipoxins are also high affinity antagonists to the cystienyl leukotriene receptor 1 (CysLT1) to which several leukotrienes (LTC4, LTD4 and LTE4) mediate their smooth muscle contraction and eosinophil chemotactic effects. The CysLT1 receptor is also the site of action for the asthma drug, Montelukast(Singulair) | Lipoxin
Lipoxins are a series of anti-inflamatory mediators. Lipoxins are short lived endogenously produced eicosanoids whose appearance in inflammation signals the resolution of inflammation. During the acute inflammatory process, the proinflammatory cytokines such as IFN-γ and IL-1β can induce the expression of anti-inflammatory mediators such as lipoxins (LXs) and IL-4, which promote the resolution phase of inflammation.[1]
They are abbreviated as LX, an acronym for lipoxygenase (LO) interaction products.
Lipoxins are derived from arachidonic acid, an ω-6 fatty acid
An analogous class, the resolvins, is derived from EPA and DHA, ω-3 fatty acids.[2]
At present two lipoxins have been identified; lipoxin A4 (LXA4) and lipoxin B4 (LXB4).
Lipoxins, as well as certain peptides, are high affinity (sub nanomolar) ligands for the lipoxin A4 receptor (ALXR), which was first identified based on sequence homology as the formyl peptide receptor like receptor (FPRL1). Lipoxin signaling through the ALXR inhibits chemotaxis, transmigration, superoxide generation and NF-kB activation.[3]
Conversely, peptide signalling through the same receptor, in vitro, has been shown to stimulate chemotaxis of PMN and calcium mobilization.[3] The peptides that have ALXR affinity tend to be signals for leukocyte migration and subsequent phagocytosis such as acute phase proteins, bacterial peptides, HIV envelope proteins and neurotoxic peptides.
Lipoxins are also high affinity antagonists to the cystienyl leukotriene receptor 1 (CysLT1) to which several leukotrienes (LTC4, LTD4 and LTE4) mediate their smooth muscle contraction and eosinophil chemotactic effects. The CysLT1 receptor is also the site of action for the asthma drug, Montelukast(Singulair)[4] | https://www.wikidoc.org/index.php/Lipoxin | |
d99fa59bb6d80c6e440251ca65dd9f7ddeb4ee24 | wikidoc | Loa loa | Loa loa
# Overview
Loa loa is the filarial nematode (roundworm) species that causes Loa loa filariasis. It is commonly known as the "eye worm". Its geographic distribution includes Africa and India.
L. loa is one of three parasitic filarial nematodes that cause subcutaneous filariasis in humans. The two other filarial nematodes are Mansonella streptocerca and Onchocerca volvulus (causes river blindness).
Maturing larvae and adults of the "eye worm" occupy the subcutaneous layer of the skin – the fat layer – of humans, causing disease. The young larvae develop in horseflies of the genus Chrysops (deer flies, yellow flies), including the species C. dimidiata and C. silacea, which infect humans by biting them.
# Biology
## Morphology
Loa loa worms have a simple body including a head, body, and tail. Males range from 20mm to 34mm long and 350μm to 430μm wide. Females range from 20mm to 70mm long and are about 425μm wide.
## Life cycle
Three species involved in the life cycle include the parasite Loa loa, the fly vector, and the human host:
- A vector fly bites an infected human host and ingests microfilariae.
- Microfilariae move to the fat body of the insect host.
- Microfilariae develop into first stage larvae, second stage, then third stage larvae.
- Third stage larvae (infective) travel to the proboscis of fly.
- An infected vector fly bites an uninfected human host and the third stage larvae penetrates the skin and enters human subcutaneous tissue.
- Larvae mature into adults, who produce microfilariae that have been found in spinal fluid, urine, peripheral blood, and lungs.
# Disease
## Pathogenesis
Loa loa parasites infect human hosts by travelling from the entry site through subcutaneous tissues and causing inflammation in the skin wherever they travel. If a parasite stops in one place for a short period of time, the human host will suffer from local inflammation known as Calabar swellings. These are localized, tense, inflammatory pruritic subcutaneous edema seen in joints of extremities, lasting for 1–3 days. They represent areas of angioedema resulting from a host response to allergens released by the maturating worm and its metabolic products. Calabar swellings often occur in the wrist and ankle joints but disappear as soon as the parasite begins to move again. Parasites can also travel through and infect the eye, causing the swelling of the eye. Common symptoms include itching, joint pain, fatigue, and death.
## Diagnosis and treatment
The main methods of diagnosis include the presence of microfilariae in the blood, the presence of a worm in the eye, and the presence of skin swellings. Surgical removal of the worm can easily be performed. The common treatment for the disease is the use of the drug Ivermectin.
Ivermectin has become the most common antiparasitic agent used worldwide but can lead to residual microfilarial load when given in the management of loiasis. High microfilarial loads should be decreased by a course of ivermectin, a prolonged administration of albendazole, or cytapheresis sessions to prevent occurrence of serious adverse events, including fatal encephalopathy induced by dying microfilariae. Cytapheresis is helpful in decreasing very high microfilarial loads up to 75%. Diethylcarbamazine kills both microfilariae and adult worms but has more severe side effects and can be fatal. | Loa loa
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
Loa loa is the filarial nematode (roundworm) species that causes Loa loa filariasis. It is commonly known as the "eye worm". Its geographic distribution includes Africa and India.[1]
L. loa is one of three parasitic filarial nematodes that cause subcutaneous filariasis in humans. The two other filarial nematodes are Mansonella streptocerca and Onchocerca volvulus (causes river blindness).
Maturing larvae and adults of the "eye worm" occupy the subcutaneous layer of the skin – the fat layer – of humans, causing disease. The young larvae develop in horseflies of the genus Chrysops (deer flies, yellow flies), including the species C. dimidiata and C. silacea, which infect humans by biting them.
# Biology
## Morphology
Loa loa worms have a simple body including a head, body, and tail. Males range from 20mm to 34mm long and 350μm to 430μm wide. Females range from 20mm to 70mm long and are about 425μm wide.[1]
## Life cycle
Three species involved in the life cycle include the parasite Loa loa, the fly vector, and the human host:[2]
- A vector fly bites an infected human host and ingests microfilariae.
- Microfilariae move to the fat body of the insect host.
- Microfilariae develop into first stage larvae, second stage, then third stage larvae.
- Third stage larvae (infective) travel to the proboscis of fly.
- An infected vector fly bites an uninfected human host and the third stage larvae penetrates the skin and enters human subcutaneous tissue.
- Larvae mature into adults, who produce microfilariae that have been found in spinal fluid, urine, peripheral blood, and lungs.
# Disease
## Pathogenesis
Loa loa parasites infect human hosts by travelling from the entry site through subcutaneous tissues and causing inflammation in the skin wherever they travel. If a parasite stops in one place for a short period of time, the human host will suffer from local inflammation known as Calabar swellings. These are localized, tense, inflammatory pruritic subcutaneous edema seen in joints of extremities, lasting for 1–3 days. They represent areas of angioedema resulting from a host response to allergens released by the maturating worm and its metabolic products.[3] Calabar swellings often occur in the wrist and ankle joints but disappear as soon as the parasite begins to move again. Parasites can also travel through and infect the eye, causing the swelling of the eye. Common symptoms include itching, joint pain, fatigue, and death.[1]
## Diagnosis and treatment
The main methods of diagnosis include the presence of microfilariae in the blood, the presence of a worm in the eye, and the presence of skin swellings. Surgical removal of the worm can easily be performed. The common treatment for the disease is the use of the drug Ivermectin.[1]
Ivermectin has become the most common antiparasitic agent used worldwide but can lead to residual microfilarial load when given in the management of loiasis. High microfilarial loads should be decreased by a course of ivermectin, a prolonged administration of albendazole, or cytapheresis sessions to prevent occurrence of serious adverse events, including fatal encephalopathy induced by dying microfilariae. Cytapheresis is helpful in decreasing very high microfilarial loads up to 75%. Diethylcarbamazine kills both microfilariae and adult worms but has more severe side effects and can be fatal. | https://www.wikidoc.org/index.php/Loa_loa | |
e6a6a30c6782d84139519ff99fa282704c5a9a79 | wikidoc | Lobelia | Lobelia
Lobelia (also known as Indian Tobacco, Asthma Weed, Pukeweed, or Vomitwort) is a genus in the family Campanulaceae, comprising over 400 species, some of which are cultivated in gardens. These include Lobelia cardinalis (Cardinal Flower or Indian Pink), Lobelia siphilitica (Blue Lobelia), Lobelia fulgens and Lobelia erinus, as well as some hybrids.
Some botanists place the genus and its relatives in the separate family Lobeliaceae. The Angiosperm Phylogeny Group did not make a firm decision in this, listing the genus under both families.
Lobelia erinus, a South African annual plant is often grown in window boxes and hanging baskets. Many varieties have been cultivated with a wide variety of colours.
Lobelia is probably the base form from which many other lobelioid genera are derived; it is therefore highly paraphyletic and not a good genus. For example, the Hawaiian species are part of a group including other genera that appear very different (see Hawaiian lobelioids). However, the group is not well-enough known to rearrange the classification.
Lobelia species are used as food plants by the larvae of some Lepidoptera species including Setaceous Hebrew Character.
The genus is named for the Belgian botanist Matthias de Lobel (1538-1616)
In the Victorian language of flowers, the lobelia symbolizes malevolence and ill will.
# Medicinal use
Native Americans used Lobelia to treat respiratory and muscle disorders, and as a purgative. Today it is used to treat asthma and food poisoning, and is often used as part of smoking cessation programs. It is a physical relaxant, and can serve as a nerve depressant, easing tension and panic. The species used most commonly in modern herbalism is Lobelia inflata (Indian Tobacco).
As used in North America, Lobelia's medicinal properties include the following: emetic (induces vomiting), stimulant, antispasmodic, expectorant, diaphoretic, relaxant, nauseant, sedative, diuretic, and nervine.
Because of its similarity to nicotine, the internal use of Lobelia may be dangerous to susceptible populations, including children, pregnant women, and individuals with cardiac disease. Excessive use will cause nausea and vomiting. It is not recommended for use by pregnant women and is best administered by a practitioner qualified in its use.
Two species, Lobelia siphilitica and Lobelia cardinalis, were considered a cure for syphilis.
Herbalist Samuel Thompson popularized medicinal use of lobelia in the United States in the early 1800s, as well as other medicinal plants like goldenseal.
One species, L. chinensis (called bàn biān lián, 半边莲 in Chinese), is used as one of the 50 fundamental herbs in traditional Chinese medicine.
# Selected species
- L. aberdarica
- L. anatina : Southwestern Blue Lobelia
- L. anceps
- L. appendiculata
- L. assurgens
- L. berlandieri
- L. boykinii
- L. canbyi
- L. cardinalis : Cardinal Flower, Scarlet Lobelia (Syn.: L. fulgens, S. splendens, L. graminea)
- L. chinensis
- L. comosa
- L. coronopifolia
- L. deckenii
- L. dortmanna
- L. erinus : Edging Lobelia, Annual Lobelia, Trailing Lobelia
- L. flaccidifolia
- L. flaccida
- L. gaudichaudii
- L. gerardii
- L. gibberoa
- L. ilicifolia (Lobelia Purpurascens): Purple Lobelia
- L. inflata : Indian Tobacco
- L. kalmii
- L. keniensis
- L. laxiflora : Sierra Madre Lobelia
- L. leschenaultiana
- L. monostachya
- L. nicotianifolia
- L. niihauensis
- L. oahuensis
- L. persicifolia
- L. pinifolia
- L. puberula
- L. pyramidalis
- L. radicans (synonym for L. chinensis)
- L. rhombifolia
- L. rosea
- L. sessilifolia
- L. siphilitica
- L. spicata
- L. telekii
- L. tenuior
- L. thapsoidea
- L. tupa
- L. urens
- L. valida
- L. zeylanica
# Notes
- ↑ Jump up to: 1.0 1.1 "Lobelia". EBSCO Complementary and Alternative Medicine (CAM) Review Board. January 2006. Retrieved 2007-09-12..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}
- ↑ Guédon, Marie-Françoise (2000). Sacred Smudging in North America. Walkabout Press.
de:Männertreu
nl:Lobelia | Lobelia
Lobelia (also known as Indian Tobacco, Asthma Weed, Pukeweed, or Vomitwort) is a genus in the family Campanulaceae, comprising over 400 species, some of which are cultivated in gardens. These include Lobelia cardinalis (Cardinal Flower or Indian Pink), Lobelia siphilitica (Blue Lobelia), Lobelia fulgens and Lobelia erinus, as well as some hybrids.
Some botanists place the genus and its relatives in the separate family Lobeliaceae. The Angiosperm Phylogeny Group did not make a firm decision in this, listing the genus under both families.
Lobelia erinus, a South African annual plant is often grown in window boxes and hanging baskets. Many varieties have been cultivated with a wide variety of colours.
Lobelia is probably the base form from which many other lobelioid genera are derived; it is therefore highly paraphyletic and not a good genus. For example, the Hawaiian species are part of a group including other genera that appear very different (see Hawaiian lobelioids). However, the group is not well-enough known to rearrange the classification.
Lobelia species are used as food plants by the larvae of some Lepidoptera species including Setaceous Hebrew Character.
The genus is named for the Belgian botanist Matthias de Lobel (1538-1616)
In the Victorian language of flowers, the lobelia symbolizes malevolence and ill will.
# Medicinal use
Native Americans used Lobelia to treat respiratory and muscle disorders, and as a purgative. Today it is used to treat asthma and food poisoning, and is often used as part of smoking cessation programs. It is a physical relaxant, and can serve as a nerve depressant, easing tension and panic. The species used most commonly in modern herbalism is Lobelia inflata (Indian Tobacco).[1]
As used in North America, Lobelia's medicinal properties include the following: emetic (induces vomiting), stimulant, antispasmodic, expectorant, diaphoretic, relaxant, nauseant, sedative, diuretic, and nervine.
Because of its similarity to nicotine, the internal use of Lobelia may be dangerous to susceptible populations, including children, pregnant women, and individuals with cardiac disease. Excessive use will cause nausea and vomiting. It is not recommended for use by pregnant women and is best administered by a practitioner qualified in its use.
Two species, Lobelia siphilitica and Lobelia cardinalis, were considered a cure for syphilis[2].
Herbalist Samuel Thompson popularized medicinal use of lobelia in the United States in the early 1800s, as well as other medicinal plants like goldenseal.[1]
One species, L. chinensis (called bàn biān lián, 半边莲 in Chinese), is used as one of the 50 fundamental herbs in traditional Chinese medicine.
# Selected species
- L. aberdarica
- L. anatina : Southwestern Blue Lobelia
- L. anceps
- L. appendiculata
- L. assurgens
- L. berlandieri
- L. boykinii
- L. canbyi
- L. cardinalis : Cardinal Flower, Scarlet Lobelia (Syn.: L. fulgens, S. splendens, L. graminea)
- L. chinensis
- L. comosa
- L. coronopifolia
- L. deckenii
- L. dortmanna
- L. erinus : Edging Lobelia, Annual Lobelia, Trailing Lobelia
- L. flaccidifolia
- L. flaccida
- L. gaudichaudii
- L. gerardii
- L. gibberoa
- L. ilicifolia (Lobelia Purpurascens): Purple Lobelia
- L. inflata : Indian Tobacco
- L. kalmii
- L. keniensis
- L. laxiflora : Sierra Madre Lobelia
- L. leschenaultiana
- L. monostachya
- L. nicotianifolia
- L. niihauensis
- L. oahuensis
- L. persicifolia
- L. pinifolia
- L. puberula
- L. pyramidalis
- L. radicans (synonym for L. chinensis)
- L. rhombifolia
- L. rosea
- L. sessilifolia
- L. siphilitica
- L. spicata
- L. telekii
- L. tenuior
- L. thapsoidea
- L. tupa
- L. urens
- L. valida
- L. zeylanica
# Notes
- ↑ Jump up to: 1.0 1.1 "Lobelia". EBSCO Complementary and Alternative Medicine (CAM) Review Board. January 2006. Retrieved 2007-09-12..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}
- ↑ Guédon, Marie-Françoise (2000). Sacred Smudging in North America. Walkabout Press.
de:Männertreu
nl:Lobelia | https://www.wikidoc.org/index.php/Lobelia | |
1e9a10a80404aecd18ade7d5c2fe4e5602f09c8f | wikidoc | Lobster | Lobster
Clawed lobsters compose a family (Nephropidae, sometimes also Homaridae) of large marine crustaceans. Lobsters are economically important as seafood, forming the basis of a global industry that nets US$1.8 billion in trade annually.
Though several different groups of crustaceans are known as "lobsters," the clawed lobsters are most often associated with the name. Clawed lobsters are not closely related with spiny lobsters or slipper lobsters, which have no claws (chelae), or squat lobsters. The closest relatives of clawed lobsters are the reef lobster Enoplometopus and the three families of freshwater crayfish.
# Biology
Lobsters are invertebrates and have a tough protective exoskeleton. Like most arthropods, lobsters must molt in order to grow, leaving them vulnerable during this time. During the molting process, several species may experience a change in color.
Lobsters live on rocky, sandy, or muddy bottoms from the shoreline to beyond the edge of the continental shelf. They generally live singly in crevices or in burrows under rocks.
Lobsters typically eat live food, consisting of fish, mollusks, other crustaceans, worms, and some plant life. Occasionally, they will scavenge if necessary, and may resort to cannibalism in captivity; however, this has not been observed in the wild. Lobster skin in the stomachs of lobsters has been found before, although this is because lobsters will eat their shed skin after molting . Lobsters grow throughout their lives and it is not unusual for a lobster to live for more than 100 years . They can thus reach impressive sizes. According to the Guinness World Records, the largest lobster was caught in Nova Scotia, Canada and weighed 20.14 kg (44.4 lb).
Being arthropods, lobsters are largely bilaterally symmetrical; clawed lobsters often possess unequal, specialized claws, like the king crab. A freshly caught lobster will have a claw that is full and fleshy, not atrophied. The anatomy of the lobster includes the cephalothorax which is the head fused with the thorax, both of which are covered by the carapace, of chitinous composition, and the abdomen. The lobster's head consists of antennae, antennules, mandibles, the first and second maxillae, and the first, second, and third maxillipeds. Because a lobster lives in a murky environment at the bottom of the ocean, its vision is poor and it mostly uses its antennae as sensors. Studies have shown that the lobster eye is formed with a reflective structure atop a convex retina. In contrast, most complex eyes use refractive ray concentrators (lenses) and a concave retina . The abdomen of the lobster includes swimmerets and its tail is composed of uropods and the telson.
In general, lobsters move slowly by walking on the bottom of the sea floor. However, when they are in danger and need to flee, they swim backwards quickly by curling and uncurling their abdomen. A speed of 5 meters per second has been recorded .
## Symbion
The genus Symbion, the only member of the phylum Cycliophora is only known from the gills of lobsters .
# List of clawed lobster species
This list contains all known species in the family Nephropidae :
# Gastronomy
Lobster is a valued foodstuff; well-known recipes include Lobster Newberg and Lobster Thermidor. Lobster is best eaten fresh, and they are normally purchased live. Lobsters are usually shipped and sold with their claws banded to prevent them from injuring each other or the purchaser. Lobsters cannot open and close the claws when they are banded, which causes the claws to begin to atrophy inside the shell. Very fresh lobsters will not show this, and the claws will be full. Many restaurants that serve lobster keep a tank of the live creatures, often allowing patrons to pick their own.
If the lobster is to be boiled or steamed, most cooks place the live lobster into the pot. If the lobster is to be fried, grilled or baked it is best not to boil the lobster before further cooking. Freezing the lobster may toughen the meat.
When boiling a lobster, the general rule of thumb is to simmer the lobster for 7 minutes for the first pound and 3 minutes for each additional pound .
The shell of the lobster makes eating them a slow process for the unskilled or timid, who may require a number of implements including nutcrackers, a small fork, and a plastic bib. It is possible to shell a lobster by hand if one is careful to avoid the sharp points. The tail can be snapped open by first squeezing its sides inward, and then grabbing the edges of the shell, placing the thumbs on the dorsal side and pulling the sides apart. The claws usually open by hyper-extending the lobster's "thumb" and then pulling it out. Sometimes the claws can then be cracked by simply squeezing them. Otherwise, an ordinary fork is usually sufficient to snap open the side of the claw. Some restaurants will split the tail of the lobster and crack the claws in the kitchen. This is done to simplify their diner's meals and in some cases as a decorative step. (Especially when the lobster is to be served with a sauce poured over the tail.)
The majority of the meat is in the tail and the two front claws, but smaller quantities can be found in the legs and torso. The larger the lobster the greater the proportion of meat in the small legs and body. Lobster can be consumed simply, boiled or steamed, or used in a wide array of dishes and salads. It can be served as lobster soup or bisque or mixed with mayonnaise or salad dressing for lobster rolls. Lobster meat is often dipped in melted butter, resulting in a sweetened flavor.
## History
The European wild lobster, among whom is the royal blue lobster of Audresselles, is more expensive and rare than the American lobster but was always appreciated chiefly among the royal and aristocratic families of France and the Netherlands. Such scenes were depicted in Dutch paintings of the sixteenth and seventeenth centuries.
In North America prior to the 20th century, local lobster was not a popular food. In the Maritimes, eating lobster was considered a mark of poverty. In some parts of the Maritime provinces of Canada, lobster was used as a fertilizer for farmers' fields, and a great deal of lobster was fed to slaves or the lower members of society. Outside of the rural outports lobster was sold canned, losing much of its flavour, which can be disguised if the lobster is dipped in drawn butter.
The reputation of lobster changed with the development of the modern transportation industry that allowed live lobsters to be shipped from the outports to large urban centres. Fresh lobster quickly became a luxury food and a tourist attraction for the Maritime provinces and Maine and an export to Europe and Japan where it is especially expensive.
The expense of eating lobster has led to supermarkets selling "faux lobster"; (which is clearly labeled as such), and it is made from fish (often pollock or other whitefish) that has been altered to look and taste similar to lobster. A few restaurants have gone so far as to sell "langostino lobster". Langostino translates into prawn, however the actual animal is, (more likely than not), a crab. Maine fishermen are upset that restaurants are passing off the fake as though is an actual lobster, (the spiny lobster is also called langouste). It is doubtful that the customers would be very happy to find out they are paying more for what is probably nothing more than a fancy-named crab. Rubio's Fresh Mexican Grill sold a "Lobster Burrito" which was made from squat lobster, another shellfish which is also very similar to the crab .
## Catching
The usual method of catching lobsters has been to use baited, one-way traps located deep underwater with a coded marker buoy at the surface so that fishermen can find their cages and not pull up someone else's traps. Around the year 2000, due to overfishing and demand overwhelming supply, many countries began to try lobster farming, which is similar to fish farming.
# Capacity for pain and suffering
The question of whether or not lobsters can experience pain is unresolved. Because of the ambiguous nature of suffering, most people who contend that lobsters do have this capacity approach the issue using 'argument by analogy' — that is, they hold that certain similarities between lobsters' and humans' biology or behavior warrants an assumption that lobsters can feel pain . In February 2005, a review of the literature by the Norwegian Scientific Committee for Food Safety tentatively concluded that "it is unlikely that can feel pain," though they note that "there is apparently a paucity of exact knowledge on sentience in crustaceans, and more research is needed." This conclusion is based on the lobster's simple nervous system. The report assumes that the violent reaction of lobsters to boiling water is a reflex to noxious stimuli . However, a Scottish review released in the same year reported that "scientific evidence ... strongly suggests that there is a potential for to experience pain and suffering," primarily because lobsters (and other decapod crustaceans) "have opioid receptors and respond to opioids (analgesics such as morphine) in a similar way to vertebrates," and because of similarities in lobsters' and vertebrates' stress systems and behavioral responses to pain .
## Opioids
In vertebrates, endogenous opioids are neurochemicals that moderate pain by interacting with opiate receptors. Opioid peptides and opiate receptors occur naturally in crustaceans, and although "at present no certain conclusion can be drawn," some have interpreted their presence as an indication that lobsters may be able to experience pain . The aforementioned Scottish paper holds that lobsters' opioids may "mediate pain in the same way" as in vertebrates .
Morphine, an analgesic, and naloxone, an opioid receptor antagonist, may affect a related species of crustacean (Chasmagnathus granulatus) in much the same way they affect vertebrates: injections of morphine into crabs produced a dose-dependent reduction of their defensive response to an electric shock . (However, the attenuated defensive response could originate from either the analgesic or sedative properties of morphine, or both .) These findings have been replicated for other invertebrate species , but similar data is not yet available for lobsters.
## Animal rights issues
The most common way of killing a lobster is by placing it, live, in boiling water. (This method is also used to kill crayfish and shrimp.) This is controversial because some people believe that the lobster suffers. The practice is illegal in some places, such as in Reggio Emilia, Italy, where offenders face fines of up to €495 . The Norwegian study states that the lobster may be de-sensitized by placing it in a salt-solution 15 minutes before killing it. The quickest way to kill a lobster may be to insert a knife into its head and cleave the head in two, thereby destroying two of the most important nerve clusters of the lobster. Some feel that this is more humane than placing the live lobster into boiling water. Freezing the lobster for 15 minutes to 2 hours before boiling may de-sensitize the lobster.
Some stores will kill a lobster upon purchase by microwaving it. Whether or not death occurs more quickly than when the lobster is dropped in boiling water is not clear. There are, however, locations where the sale of a dead lobster to be eaten is illegal, including Massachusetts .
In 2006, British inventor Simon Buckhaven invented the CrustaStun, which electrocutes lobsters with a 110 V electric shock, killing them in about five seconds. This ensures a quicker death for the lobster. Seafood wholesalers in Britain already use a commercial version. A home version measuring about 46 cm width and depth came into the retail market in late 2006 for about GB£2000 .
# Lobsters in culture
The Moche people of ancient Peru worshipped the sea and its animals. Lobsters were often depicted in their art . | Lobster
Clawed lobsters compose a family (Nephropidae, sometimes also Homaridae) of large marine crustaceans. Lobsters are economically important as seafood, forming the basis of a global industry that nets US$1.8 billion in trade annually.
Though several different groups of crustaceans are known as "lobsters," the clawed lobsters are most often associated with the name. Clawed lobsters are not closely related with spiny lobsters or slipper lobsters, which have no claws (chelae), or squat lobsters. The closest relatives of clawed lobsters are the reef lobster Enoplometopus and the three families of freshwater crayfish.
# Biology
Lobsters are invertebrates and have a tough protective exoskeleton. Like most arthropods, lobsters must molt in order to grow, leaving them vulnerable during this time. During the molting process, several species may experience a change in color.
Lobsters live on rocky, sandy, or muddy bottoms from the shoreline to beyond the edge of the continental shelf. They generally live singly in crevices or in burrows under rocks.
Lobsters typically eat live food, consisting of fish, mollusks, other crustaceans, worms, and some plant life. Occasionally, they will scavenge if necessary, and may resort to cannibalism in captivity; however, this has not been observed in the wild. Lobster skin in the stomachs of lobsters has been found before, although this is because lobsters will eat their shed skin after molting [1]. Lobsters grow throughout their lives and it is not unusual for a lobster to live for more than 100 years [2]. They can thus reach impressive sizes. According to the Guinness World Records, the largest lobster was caught in Nova Scotia, Canada and weighed 20.14 kg (44.4 lb).
Being arthropods, lobsters are largely bilaterally symmetrical; clawed lobsters often possess unequal, specialized claws, like the king crab. A freshly caught lobster will have a claw that is full and fleshy, not atrophied. The anatomy of the lobster includes the cephalothorax which is the head fused with the thorax, both of which are covered by the carapace, of chitinous composition, and the abdomen. The lobster's head consists of antennae, antennules, mandibles, the first and second maxillae, and the first, second, and third maxillipeds. Because a lobster lives in a murky environment at the bottom of the ocean, its vision is poor and it mostly uses its antennae as sensors. Studies have shown that the lobster eye is formed with a reflective structure atop a convex retina. In contrast, most complex eyes use refractive ray concentrators (lenses) and a concave retina [3]. The abdomen of the lobster includes swimmerets and its tail is composed of uropods and the telson.
In general, lobsters move slowly by walking on the bottom of the sea floor. However, when they are in danger and need to flee, they swim backwards quickly by curling and uncurling their abdomen. A speed of 5 meters per second has been recorded [4].
## Symbion
The genus Symbion, the only member of the phylum Cycliophora is only known from the gills of lobsters [5].
# List of clawed lobster species
This list contains all known species in the family Nephropidae [6]:
# Gastronomy
Lobster is a valued foodstuff; well-known recipes include Lobster Newberg and Lobster Thermidor. Lobster is best eaten fresh, and they are normally purchased live. Lobsters are usually shipped and sold with their claws banded to prevent them from injuring each other or the purchaser. Lobsters cannot open and close the claws when they are banded, which causes the claws to begin to atrophy inside the shell. Very fresh lobsters will not show this, and the claws will be full. Many restaurants that serve lobster keep a tank of the live creatures, often allowing patrons to pick their own.
If the lobster is to be boiled or steamed, most cooks place the live lobster into the pot. If the lobster is to be fried, grilled or baked it is best not to boil the lobster before further cooking. Freezing the lobster may toughen the meat.
When boiling a lobster, the general rule of thumb is to simmer the lobster for 7 minutes for the first pound and 3 minutes for each additional pound [7].
The shell of the lobster makes eating them a slow process for the unskilled or timid, who may require a number of implements including nutcrackers, a small fork, and a plastic bib. It is possible to shell a lobster by hand if one is careful to avoid the sharp points. The tail can be snapped open by first squeezing its sides inward, and then grabbing the edges of the shell, placing the thumbs on the dorsal side and pulling the sides apart. The claws usually open by hyper-extending the lobster's "thumb" and then pulling it out. Sometimes the claws can then be cracked by simply squeezing them. Otherwise, an ordinary fork is usually sufficient to snap open the side of the claw. Some restaurants will split the tail of the lobster and crack the claws in the kitchen. This is done to simplify their diner's meals and in some cases as a decorative step. (Especially when the lobster is to be served with a sauce poured over the tail.)
The majority of the meat is in the tail and the two front claws, but smaller quantities can be found in the legs and torso. The larger the lobster the greater the proportion of meat in the small legs and body. Lobster can be consumed simply, boiled or steamed, or used in a wide array of dishes and salads. It can be served as lobster soup or bisque or mixed with mayonnaise or salad dressing for lobster rolls. Lobster meat is often dipped in melted butter, resulting in a sweetened flavor.
## History
The European wild lobster, among whom is the royal blue lobster of Audresselles, is more expensive and rare than the American lobster but was always appreciated chiefly among the royal and aristocratic families of France and the Netherlands. Such scenes were depicted in Dutch paintings of the sixteenth and seventeenth centuries.
In North America prior to the 20th century, local lobster was not a popular food. In the Maritimes, eating lobster was considered a mark of poverty. In some parts of the Maritime provinces of Canada, lobster was used as a fertilizer for farmers' fields, and a great deal of lobster was fed to slaves or the lower members of society. Outside of the rural outports lobster was sold canned, losing much of its flavour, which can be disguised if the lobster is dipped in drawn butter.
The reputation of lobster changed with the development of the modern transportation industry that allowed live lobsters to be shipped from the outports to large urban centres. Fresh lobster quickly became a luxury food and a tourist attraction for the Maritime provinces and Maine and an export to Europe and Japan where it is especially expensive.
The expense of eating lobster has led to supermarkets selling "faux lobster"; (which is clearly labeled as such), and it is made from fish (often pollock or other whitefish) that has been altered to look and taste similar to lobster. A few restaurants have gone so far as to sell "langostino lobster". Langostino translates into prawn, however the actual animal is, (more likely than not), a crab. Maine fishermen are upset that restaurants are passing off the fake as though is an actual lobster, (the spiny lobster is also called langouste). It is doubtful that the customers would be very happy to find out they are paying more for what is probably nothing more than a fancy-named crab. Rubio's Fresh Mexican Grill sold a "Lobster Burrito" which was made from squat lobster, another shellfish which is also very similar to the crab [8].
## Catching
The usual method of catching lobsters has been to use baited, one-way traps located deep underwater with a coded marker buoy at the surface so that fishermen can find their cages and not pull up someone else's traps. Around the year 2000, due to overfishing and demand overwhelming supply, many countries began to try lobster farming, which is similar to fish farming.
# Capacity for pain and suffering
The question of whether or not lobsters can experience pain is unresolved. Because of the ambiguous nature of suffering, most people who contend that lobsters do have this capacity approach the issue using 'argument by analogy' — that is, they hold that certain similarities between lobsters' and humans' biology or behavior warrants an assumption that lobsters can feel pain [9]. In February 2005, a review of the literature by the Norwegian Scientific Committee for Food Safety tentatively concluded that "it is unlikely that [lobsters] can feel pain," though they note that "there is apparently a paucity of exact knowledge on sentience in crustaceans, and more research is needed." This conclusion is based on the lobster's simple nervous system. The report assumes that the violent reaction of lobsters to boiling water is a reflex to noxious stimuli [10]. However, a Scottish review released in the same year reported that "scientific evidence ... strongly suggests that there is a potential for [lobsters] to experience pain and suffering," primarily because lobsters (and other decapod crustaceans) "have opioid receptors and respond to opioids (analgesics such as morphine) in a similar way to vertebrates," and because of similarities in lobsters' and vertebrates' stress systems and behavioral responses to pain [9].
## Opioids
In vertebrates, endogenous opioids are neurochemicals that moderate pain by interacting with opiate receptors. Opioid peptides and opiate receptors occur naturally in crustaceans, and although "at present no certain conclusion can be drawn,"[10] some have interpreted their presence as an indication that lobsters may be able to experience pain [10][9]. The aforementioned Scottish paper holds that lobsters' opioids may "mediate pain in the same way" as in vertebrates [9].
Morphine, an analgesic, and naloxone, an opioid receptor antagonist, may affect a related species of crustacean (Chasmagnathus granulatus) in much the same way they affect vertebrates: injections of morphine into crabs produced a dose-dependent reduction of their defensive response to an electric shock [11]. (However, the attenuated defensive response could originate from either the analgesic or sedative properties of morphine, or both [12].) These findings have been replicated for other invertebrate species [12], but similar data is not yet available for lobsters.
## Animal rights issues
The most common way of killing a lobster is by placing it, live, in boiling water. (This method is also used to kill crayfish and shrimp.) This is controversial because some people believe that the lobster suffers. The practice is illegal in some places, such as in Reggio Emilia, Italy, where offenders face fines of up to €495 [13]. The Norwegian study states that the lobster may be de-sensitized by placing it in a salt-solution 15 minutes before killing it. The quickest way to kill a lobster may be to insert a knife into its head and cleave the head in two, thereby destroying two of the most important nerve clusters of the lobster. Some feel that this is more humane than placing the live lobster into boiling water. Freezing the lobster for 15 minutes to 2 hours before boiling may de-sensitize the lobster.
Some stores will kill a lobster upon purchase by microwaving it. Whether or not death occurs more quickly than when the lobster is dropped in boiling water is not clear. There are, however, locations where the sale of a dead lobster to be eaten is illegal, including Massachusetts [14].
In 2006, British inventor Simon Buckhaven invented the CrustaStun, which electrocutes lobsters with a 110 V electric shock, killing them in about five seconds. This ensures a quicker death for the lobster. Seafood wholesalers in Britain already use a commercial version. A home version measuring about 46 cm width and depth came into the retail market in late 2006 for about GB£2000 [15][16].
# Lobsters in culture
The Moche people of ancient Peru worshipped the sea and its animals. Lobsters were often depicted in their art [17]. | https://www.wikidoc.org/index.php/Lobster | |
45a81326eee84f99c1497823e7bb4d959abffcf1 | wikidoc | Lovemap | Lovemap
A lovemap is a concept originated by John Money to assist a discussion of why people like what they enjoy sexually and erotically. According to Money, it is "a developmental representation or template in the mind and in the brain depicting the idealized lover and the idealized program of sexual and erotic activity projected in imagery or actually engaged in with that lover."
A lovemap can be shaped by both positive and negative factors, things that attract or repel the person whose erotic tastes are being mapped. For reasons that are not always easy to understand, one person may be attracted to people of a particular gender, with a particular physical characteristic, with particular personality traits, and so forth. One may also find certain characteristics so threatening or objectionable that it strongly mitigates against an erotic attraction being manifested.
A lovemap can be shaped by environmental factors that facilitate the formation of an erotic bond, or that enhance or diminish erotic response. For instance, some people may bond strongly to people with whom they share a crisis situation. Some people may find their erotic responses muted in the presence of intimidating environmental factors (observant elders or nosy neighbors, for instance).
# Origin
According to Money, the word lovemap was first used in 1980 in an article entitled: “Pairbonding and Limerence”. Before this time, as he states, Money began to talk about lovemaps, in precursory form, with his students in lectures. The seed for this concept can be found in his 1980 book "Love and Lovesickness: the Science of Sex, Gender Difference and Pairbonding”, where on page 65 he states:
# Overview
Like the acquirement of a native language, a person’s lovemap also bears the mark of his or her own unique individuality, or accent. A lovemap is usually quite specific as to details of the physiognomy, build, race, and color of the ideal lover, not to mention temperament, manner, etc. Since its inception, the concept of “love maps”, applied to interpersonal relationships, has found apt acceptance and is frequently referenced in love / relationship / sexual-evolution theory books; as for example in Wilson and McLaughlin’s 2001 The Science of Love.
In "Gay, Straight, and In-Between: The Sexology of Erotic Orientation," Money (1988: 127-128) suggests that love is like a Rorschach (ink blot) test, where if projections (shaped by a body/mind's lovemap) on the other are mutual, pair-bonding occurs, typically in a courtship phase of mating.
# Variations
- Heterosexual lovemaps – love mappings associative to the average or typical sexual relationships.
- Homosexual lovemaps – love mappings associative to persons of the same gender. Generally regarded as atypical, as this encompasses only a minority of the population, it still occurs nonetheless in every culture and generation.
- Vandalized lovemaps – is when the love mapping process or neurological template development stage becomes traumatized, as in for example being exposed at a young age, typically five to eight, to the sights, sounds and tortures of paraphilic sadist or masochist parents; or as in being led into a pedophilic relationship; or as being involved in an incestuous relationship.
- Paraphilic lovemaps – when lust is attached to fantasies and practices that are socially forbidden, disapproved, ridiculed, or penalized; sometimes as a result of birth deformity (micropenis), chromosomal abnormality (45, X/46, XY), or as in accelerated growth (premature puberty).
- Native lovemap - by analogy with native language, is a lovemap that is assimilated as one's own personal, inalienable possession, regardless of how many of its attributes are shared, or not shared by others.
- Klismaphilic lovemap – specifies both in fantasy and performance that the person’s sexual and erotic will be aroused, and orgasm achieved, only if the partner participates in a scenario of administering an enema.
- Acrotomophilic lovemap – specifies a paraphilia of the stigmatic/eligibilic type in which sexual and erotic arousal and facilitation of attainment of orgasm are responsive to, and dependent upon a partner who is an amputee, or in extreme cases a thalidomide baby who has reached adulthood.
- Zoophilic lovemap – specifies a paraphilia of the stigmatic/eligibilic type in which sexual and erotic arousal and facilitation of attainment of orgasm are responsive to, and dependent upon engaging in cross-species sexual activities, that is, with an animal. | Lovemap
A lovemap is a concept originated by John Money to assist a discussion of why people like what they enjoy sexually and erotically. According to Money, it is "a developmental representation or template in the mind and in the brain depicting the idealized lover and the idealized program of sexual and erotic activity projected in imagery or actually engaged in with that lover."[1]
A lovemap can be shaped by both positive and negative factors, things that attract or repel the person whose erotic tastes are being mapped. For reasons that are not always easy to understand, one person may be attracted to people of a particular gender, with a particular physical characteristic, with particular personality traits, and so forth. One may also find certain characteristics so threatening or objectionable that it strongly mitigates against an erotic attraction being manifested.
A lovemap can be shaped by environmental factors that facilitate the formation of an erotic bond, or that enhance or diminish erotic response. For instance, some people may bond strongly to people with whom they share a crisis situation. Some people may find their erotic responses muted in the presence of intimidating environmental factors (observant elders or nosy neighbors, for instance).
# Origin
According to Money, the word lovemap was first used in 1980 in an article entitled: “Pairbonding and Limerence”. Before this time, as he states, Money began to talk about lovemaps, in precursory form, with his students in lectures. The seed for this concept can be found in his 1980 book "Love and Lovesickness: the Science of Sex, Gender Difference and Pairbonding”, where on page 65 he states:
# Overview
Like the acquirement of a native language, a person’s lovemap also bears the mark of his or her own unique individuality, or accent. A lovemap is usually quite specific as to details of the physiognomy, build, race, and color of the ideal lover, not to mention temperament, manner, etc. Since its inception, the concept of “love maps”, applied to interpersonal relationships, has found apt acceptance and is frequently referenced in love / relationship / sexual-evolution theory books; as for example in Wilson and McLaughlin’s 2001 The Science of Love.[2]
In "Gay, Straight, and In-Between: The Sexology of Erotic Orientation," Money (1988: 127-128) suggests that love is like a Rorschach (ink blot) test, where if projections (shaped by a body/mind's lovemap) on the other are mutual, pair-bonding occurs, typically in a courtship phase of mating.
# Variations
- Heterosexual lovemaps – love mappings associative to the average or typical sexual relationships.
- Homosexual lovemaps – love mappings associative to persons of the same gender. Generally regarded as atypical, as this encompasses only a minority of the population, it still occurs nonetheless in every culture and generation.
- Vandalized lovemaps – is when the love mapping process or neurological template development stage becomes traumatized, as in for example being exposed at a young age, typically five to eight, to the sights, sounds and tortures of paraphilic sadist or masochist parents; or as in being led into a pedophilic relationship; or as being involved in an incestuous relationship.
- Paraphilic lovemaps – when lust is attached to fantasies and practices that are socially forbidden, disapproved, ridiculed, or penalized; sometimes as a result of birth deformity (micropenis), chromosomal abnormality (45, X/46, XY), or as in accelerated growth (premature puberty).
- Native lovemap - by analogy with native language, is a lovemap that is assimilated as one's own personal, inalienable possession, regardless of how many of its attributes are shared, or not shared by others.
- Klismaphilic lovemap – specifies both in fantasy and performance that the person’s sexual and erotic will be aroused, and orgasm achieved, only if the partner participates in a scenario of administering an enema.
- Acrotomophilic lovemap – specifies a paraphilia of the stigmatic/eligibilic type in which sexual and erotic arousal and facilitation of attainment of orgasm are responsive to, and dependent upon a partner who is an amputee, or in extreme cases a thalidomide baby who has reached adulthood.
- Zoophilic lovemap – specifies a paraphilia of the stigmatic/eligibilic type in which sexual and erotic arousal and facilitation of attainment of orgasm are responsive to, and dependent upon engaging in cross-species sexual activities, that is, with an animal.[3] | https://www.wikidoc.org/index.php/Lovemap | |
9b6369f7fe2586e6f2517b4efd89da2bc97727d0 | wikidoc | Lumican | Lumican
Lumican, also known as LUM, is an extracellular matrix protein that, in humans, is encoded by the LUM gene on chromosome 12.
# Structure
Lumican is a proteoglycan Class II member of the small leucine-rich proteoglycan (SLRP) family that includes decorin, biglycan, fibromodulin, keratocan, epiphycan, and osteoglycin.
Like the other SLRPs, lumican has a molecular weight of about 40 kiloDaltons and has four major intramolecular domains:
- a signal peptide of 16 amino acid residues;
- a negatively-charged N-terminal domain containing sulfated tyrosine and disulfide bond(s);
- ten tandem leucine-rich repeats allowing lumican to bind to other extracellular components such as collagen;
- a carboxyl terminal domain of 50 amino acid residues containing two conserved cysteines 32 residues apart.
There are four N-linked sites within the leucine-rich repeat domain of the protein core that can be substituted with keratan sulfate. The core protein of lumican (like decorin and fibromodulin) is horseshoe shaped. This enables it bind to collagen molecules within a collagen fibril, thus helping keep adjacent fibrils apart.
# Function
Lumican is a major keratan sulfate proteoglycan of the cornea but is ubiquitously distributed in most mesenchymal tissues throughout the body. Lumican is involved in collagen fibril organization and circumferential growth, corneal transparency, and epithelial cell migration and tissue repair. Corneal transparency is possible due to the exact alignment of collagen fibers by lumican (and keratocan) in the intrafibrillar space.
# Clinical significance
Mice that have the lumican gene knocked out (Lum-/-) develop opacities of the cornea in both eyes and fragile skin. The lumican (LUM) gene was thought to be a candidate susceptibility gene for high myopia; however, a meta-analysis showed no association between LUM polymorphism and high myopia susceptibility in all genetic models studied.
Lum knockout mice also have abnormal collagen in their heart tissue, with fewer and thicker fibrils. Mice deficient in both lumican and fibromodulin develop severe tendinopathy (tendon pathology), revealing the importance of these SLRPs in the development of correctly sized and aligned collagen fibers in tendon. Along with other extracellular matrix components, lumican expression was increased in equine flexor tendons six weeks after an injury.
Lumican is present in the extracellular matrix of uteral tissues in fertile women. There is an increase of lumican during the proliferative to secretory phase of the endometrium. In menopausal endometrial tissue, the level of lumican expression decreases and is also low in pathological compared to normal endometrium.
Lumican is highly expressed in pleural effusions (lung fluid) of patients with adenocarcinoma. Its expression was low in cancer cells but high in the extracellular matrix surrounding the tumor. Lumican expression was not associated with tumor grade or stage. In about half the patients with pancreatic ductal adenocarcinoma tested, lumican in the extracellular matrix around the tumor was associated with a reduction in metastatic recurrence after surgery and with a three-fold longer survival than patients without stromal lumican. As lumican can directly bind to and inhibit matrix metalloproteinase-14 (MMP14), lumican may limit tumor progression by preventing extracellular matrix collagen proteolysis by this enzyme. | Lumican
Lumican, also known as LUM, is an extracellular matrix protein that, in humans, is encoded by the LUM gene on chromosome 12.[1][2]
# Structure
Lumican is a proteoglycan Class II member of the small leucine-rich proteoglycan (SLRP) family that includes decorin, biglycan, fibromodulin, keratocan, epiphycan, and osteoglycin.[3]
Like the other SLRPs, lumican has a molecular weight of about 40 kiloDaltons and has four major intramolecular domains:[4]
- a signal peptide of 16 amino acid residues;
- a negatively-charged N-terminal domain containing sulfated tyrosine and disulfide bond(s);
- ten tandem leucine-rich repeats allowing lumican to bind to other extracellular components such as collagen;
- a carboxyl terminal domain of 50 amino acid residues containing two conserved cysteines 32 residues apart.
There are four N-linked sites within the leucine-rich repeat domain of the protein core that can be substituted with keratan sulfate. The core protein of lumican (like decorin and fibromodulin) is horseshoe shaped. This enables it bind to collagen molecules within a collagen fibril, thus helping keep adjacent fibrils apart.[5]
# Function
Lumican is a major keratan sulfate proteoglycan of the cornea but is ubiquitously distributed in most mesenchymal tissues throughout the body.[6] Lumican is involved in collagen fibril organization and circumferential growth, corneal transparency, and epithelial cell migration and tissue repair.[1] Corneal transparency is possible due to the exact alignment of collagen fibers by lumican (and keratocan) in the intrafibrillar space.
# Clinical significance
Mice that have the lumican gene knocked out (Lum-/-) develop opacities of the cornea in both eyes and fragile skin.[7] The lumican (LUM) gene was thought to be a candidate susceptibility gene for high myopia; however, a meta-analysis showed no association between LUM polymorphism and high myopia susceptibility in all genetic models studied.[8]
Lum knockout mice also have abnormal collagen in their heart tissue, with fewer and thicker fibrils.[9] Mice deficient in both lumican and fibromodulin develop severe tendinopathy (tendon pathology), revealing the importance of these SLRPs in the development of correctly sized and aligned collagen fibers in tendon.[10] Along with other extracellular matrix components, lumican expression was increased in equine flexor tendons six weeks after an injury.[11]
Lumican is present in the extracellular matrix of uteral tissues in fertile women.[12] There is an increase of lumican during the proliferative to secretory phase of the endometrium. In menopausal endometrial tissue, the level of lumican expression decreases and is also low in pathological compared to normal endometrium.
Lumican is highly expressed in pleural effusions (lung fluid) of patients with adenocarcinoma.[13] Its expression was low in cancer cells but high in the extracellular matrix surrounding the tumor. Lumican expression was not associated with tumor grade or stage. In about half the patients with pancreatic ductal adenocarcinoma tested,[14] lumican in the extracellular matrix around the tumor was associated with a reduction in metastatic recurrence after surgery and with a three-fold longer survival than patients without stromal lumican. As lumican can directly bind to and inhibit matrix metalloproteinase-14 (MMP14), lumican may limit tumor progression by preventing extracellular matrix collagen proteolysis by this enzyme.[15] | https://www.wikidoc.org/index.php/Lumican | |
9a40fcd1c5e6dd4d897ae6eab78ddd8c401ebf4a | wikidoc | Lunatic | Lunatic
# Background
A lunatic (colloquially: "looney") is a commonly used term for a person who is mentally ill, dangerous, foolish or unpredictable, a condition once called lunacy.
The word lunatic is borrowed from Latin "lunaticus", which gains its stem from "luna" for moon, which denotes the traditional link made in folklore between madness and the phases of the moon. This probably refers to the symptoms of cyclic mood disorders such as bipolar disorder or cyclothymia, the symptoms of which may also go through phases. As yet there is little evidence for any causal link between phases of the moon and the progression of mood disorder symptoms.
In a 1999 Journal of Affective Disorders article, a hypothesis was suggested indicating that the phase of the moon may in the past have had an effect on bipolar patients by providing light during nights which would otherwise have been dark, and affecting susceptible patients through the well-known route of sleep deprivation. With the introduction of electric light, this effect would have gone away, as light would be available every night, explaining the negative results of modern studies. They suggest ways in which this hypothesis might be tested.
Mental institutions used to be called "lunatic asylums" or colloquially, "loony bins".
In Russian, Polish and Czech, a lunatic refers to a sleepwalker, literally "one who walks under the moon" or "moon walker".
In Romanian, a word with the meaning of "lunatic" is "zănatic", derived from Latin "dianaticus", from Diana, the Roman goddess of the Moon.
In England and Wales the Lunacy Acts 1890 - 1922 referred to lunatics, but the Mental Treatment Act 1930 changed the legal term to Person of Unsound Mind, an expression which was replaced under the Mental Health Act 1959 by mental illness. Person of unsound mind was the term used in 1950 in the English version of the European Convention on Human Rights as one of the types of person who could be deprived of liberty by a judicial process. The 1930 act also replaced Asylum by Mental Hospital. Criminal Lunatics became Broadmoor Patients in 1948 under the National Health Service Act. The terms are still used by journalists, especially in tabloid newspapers.
# Lunar Distance
The term lunatic was also used by supporters of John Harrison and his marine chronometer method of determining longitude to refer to proponents of the Method of Lunar Distances, advanced by Astronomer Royal Nevil Maskelyne.
Later, members of the Lunar Society of Birmingham called themselves lunaticks. In an age with little street lighting, the society met on or about the night of the full moon. | Lunatic
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Background
A lunatic (colloquially: "looney") is a commonly used term for a person who is mentally ill, dangerous, foolish or unpredictable, a condition once called lunacy.
The word lunatic is borrowed from Latin "lunaticus", which gains its stem from "luna" for moon, which denotes the traditional link made in folklore between madness and the phases of the moon. This probably refers to the symptoms of cyclic mood disorders such as bipolar disorder or cyclothymia, the symptoms of which may also go through phases. As yet there is little evidence for any causal link between phases of the moon and the progression of mood disorder symptoms.
In a 1999 Journal of Affective Disorders article, a hypothesis was suggested indicating that the phase of the moon may in the past have had an effect on bipolar patients by providing light during nights which would otherwise have been dark, and affecting susceptible patients through the well-known route of sleep deprivation. With the introduction of electric light, this effect would have gone away, as light would be available every night, explaining the negative results of modern studies. They suggest ways in which this hypothesis might be tested.
Mental institutions used to be called "lunatic asylums" or colloquially, "loony bins".
In Russian, Polish and Czech, a lunatic refers to a sleepwalker, literally "one who walks under the moon" or "moon walker".
In Romanian, a word with the meaning of "lunatic" is "zănatic", derived from Latin "dianaticus", from Diana, the Roman goddess of the Moon.[1]
In England and Wales the Lunacy Acts 1890 - 1922 referred to lunatics, but the Mental Treatment Act 1930 changed the legal term to Person of Unsound Mind, an expression which was replaced under the Mental Health Act 1959 by mental illness. Person of unsound mind was the term used in 1950 in the English version of the European Convention on Human Rights as one of the types of person who could be deprived of liberty by a judicial process. The 1930 act also replaced Asylum by Mental Hospital. Criminal Lunatics became Broadmoor Patients in 1948 under the National Health Service Act. The terms are still used by journalists, especially in tabloid newspapers.
# Lunar Distance
The term lunatic was also used by supporters of John Harrison and his marine chronometer method of determining longitude to refer to proponents of the Method of Lunar Distances, advanced by Astronomer Royal Nevil Maskelyne.
Later, members of the Lunar Society of Birmingham called themselves lunaticks. In an age with little street lighting, the society met on or about the night of the full moon. | https://www.wikidoc.org/index.php/Lunatic | |
1aeb67dae59ab49be294209fc4ae8d270cefa179 | wikidoc | MAGEA11 | MAGEA11
Melanoma-associated antigen 11 is a protein that in humans is encoded by the MAGEA11 gene. It is also involved in the androgen and progesterone receptor signaling pathways.
MAGEA11 is an androgen coregulator specific to primates. It was first identified in human melanomas, and has since been linked to several cancers. It is observed on spermatogonia and primary spermatocytes, and in some prostate and breast cancers.
This gene is a member of the MAGEA gene family. The members of this family encode proteins with 50 to 80% sequence identity to each other. The promoters and first exons of the MAGEA genes show considerable variability, suggesting that the existence of this gene family enables the same function to be expressed under different transcriptional controls. The MAGEA genes are clustered at chromosomal location Xq28. They have been implicated in some hereditary disorders, such as . Two transcript variants encoding different isoforms have been found for this gene.
# Interactions
MAGEA11 has been shown to interact with TCEA2, androgen receptor and SH2D4A.
# Genetics
MAGE-A genes have several noncoding exons followed by one protein-coding exon. MAGEA11 is mapped to the human chromosome X, forming a locus at q28 with other MAGE-A proteins. MAGE-A11 is located between two copies of MAGEA9 and MAGEA8, and is immediately downstream of the duplicated area. Its sublocus is about 2 Mb from the second sublocus containing the other MAGEA genes.
# Androgen receptor
MAGE-A11 is part of the androgen receptor signaling pathway in humans. It binds directly to the androgen receptor, promoting transcriptional through direct binding to the androgen receptor FXXLF motif region. This control is specific to primates, and is due to a mutation in the androgen receptor from alanine to valine at residue 33, which extends the α-helix, which enables direct MAGE-A11 binding to the androgen receptor. Post-translational modification of the protein by phosphorylation of Thr-360 and monoubiquitinylation of Lys-240 and Lys-245 also stabilizes the interaction with the androgen receptor. MAGE-A11 likely links transcriptionally active androgen receptor dimers. The MAGE-A11 dependent increase in androgen receptor transcriptional activity is mediated by a direct interaction of MAGE-A11 and transcriptional intermediary factor 2 (TIF2), suggesting that MAGE-A11 may act as a bridging factor to recruit other androgen receptor coactivators. Mutations in the androgen receptor that interfere with binding of MAGE-A11 can cause partial androgen insensitivity syndrome.
# Progesterone receptor
MAGE-A11 also acts as an isoform-specific coregulator of full-length human progesterone receptor-B through an interaction with the receptor's N terminal. It increases progesterone and glucocorticoid receptor activity, resulting in greater regulatory control over activation domain dominance compared to mice.
# Cancer
Most MAGE-A genes are not expressed in healthy tissues except testicular, ovarian, and placental germ cells. They are expressed in tumor cells. MAGE-A11 in particular shows high expression in a small number of tumors, but low levels in all others.
## Breast cancers
The MAGE-A family are linked to many kinds of cancerous tumors. MAGE-A11 expression is positively associated with HER-2 expression, and increased MAGE-A11 concentrations are associated with shorter life expectancies of patients with breast cancer.
## Prostate cancer
Increased expression of MAGE-A11 during prostate cancer progression enhances both the androgen receptor signaling pathway and cancer growth. MAGE-A11 mRNA levels increase significantly during androgen deprivation therapy to treat prostate cancer, and MAGE-A11 levels have been found to be highest in castration-recurrent prostate cancer. The drastic increase is the result of DNA hypomethylation of a CpG island in the 5’ promoter of the MAGE-A11 gene. Cyclic AMP has also been found to increase MAGE-A11 expression as well as androgen receptor activity in prostate cancer cell lines, and extensive DNA methylation of the promoter inhibits the effects of cAMP. | MAGEA11
Melanoma-associated antigen 11 is a protein that in humans is encoded by the MAGEA11 gene.[1][2] It is also involved in the androgen and progesterone receptor signaling pathways.
MAGEA11 is an androgen coregulator specific to primates.[3] It was first identified in human melanomas, and has since been linked to several cancers.[4] It is observed on spermatogonia and primary spermatocytes, and in some prostate and breast cancers.[5]
This gene is a member of the MAGEA gene family. The members of this family encode proteins with 50 to 80% sequence identity to each other. The promoters and first exons of the MAGEA genes show considerable variability, suggesting that the existence of this gene family enables the same function to be expressed under different transcriptional controls. The MAGEA genes are clustered at chromosomal location Xq28. They have been implicated in some hereditary disorders, such as [dyskeratosis congenita]. Two transcript variants encoding different isoforms have been found for this gene.[2]
# Interactions
MAGEA11 has been shown to interact with TCEA2,[6] androgen receptor[7][8] and SH2D4A.[6]
# Genetics
MAGE-A genes have several noncoding exons followed by one protein-coding exon. MAGEA11 is mapped to the human chromosome X, forming a locus at q28 with other MAGE-A proteins. MAGE-A11 is located between two copies of MAGEA9 and MAGEA8, and is immediately downstream of the duplicated area. Its sublocus is about 2 Mb from the second sublocus containing the other MAGEA genes.[4]
# Androgen receptor
MAGE-A11 is part of the androgen receptor signaling pathway in humans. It binds directly to the androgen receptor, promoting transcriptional through direct binding to the androgen receptor FXXLF motif region.[3][9] This control is specific to primates, and is due to a mutation in the androgen receptor from alanine to valine at residue 33, which extends the α-helix, which enables direct MAGE-A11 binding to the androgen receptor.[3] Post-translational modification of the protein by phosphorylation of Thr-360 and monoubiquitinylation of Lys-240 and Lys-245 also stabilizes the interaction with the androgen receptor.[10] MAGE-A11 likely links transcriptionally active androgen receptor dimers.[11] The MAGE-A11 dependent increase in androgen receptor transcriptional activity is mediated by a direct interaction of MAGE-A11 and transcriptional intermediary factor 2 (TIF2), suggesting that MAGE-A11 may act as a bridging factor to recruit other androgen receptor coactivators.[10] Mutations in the androgen receptor that interfere with binding of MAGE-A11 can cause partial androgen insensitivity syndrome.[12]
# Progesterone receptor
MAGE-A11 also acts as an isoform-specific coregulator of full-length human progesterone receptor-B through an interaction with the receptor's N terminal.[11] It increases progesterone and glucocorticoid receptor activity, resulting in greater regulatory control over activation domain dominance compared to mice.[3]
# Cancer
Most MAGE-A genes are not expressed in healthy tissues except testicular, ovarian, and placental germ cells. They are expressed in tumor cells. MAGE-A11 in particular shows high expression in a small number of tumors, but low levels in all others.[13]
## Breast cancers
The MAGE-A family are linked to many kinds of cancerous tumors. MAGE-A11 expression is positively associated with HER-2 expression, and increased MAGE-A11 concentrations are associated with shorter life expectancies of patients with breast cancer.[14]
## Prostate cancer
Increased expression of MAGE-A11 during prostate cancer progression enhances both the androgen receptor signaling pathway and cancer growth. MAGE-A11 mRNA levels increase significantly during androgen deprivation therapy to treat prostate cancer, and MAGE-A11 levels have been found to be highest in castration-recurrent prostate cancer.[11][15] The drastic increase is the result of DNA hypomethylation of a CpG island in the 5’ promoter of the MAGE-A11 gene. Cyclic AMP has also been found to increase MAGE-A11 expression as well as androgen receptor activity in prostate cancer cell lines, and extensive DNA methylation of the promoter inhibits the effects of cAMP.[15] | https://www.wikidoc.org/index.php/MAGEA11 | |
860851a78629be8a6cdd4107de47938e88557331 | wikidoc | MAP3K11 | MAP3K11
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Mitogen-activated protein kinase kinase kinase 11 is an enzyme that in humans is encoded by the MAP3K11 gene.
# Function
The protein encoded by this gene is called MLK3 and it is a member of the serine/threonine kinase family. This kinase contains a SH3 domain and a leucine zipper-basic motif. This kinase preferentially activates MAPK8/JNK kinase, and functions as a positive regulator of JNK signaling pathway. This kinase can directly phosphorylate, and activates JNK and p38, and is found to be involved in the transcription activity of AP1 mediated by Rho family GTPases and CDC42.
# Interactions
MAP3K11 has been shown to interact with:
- AKT1,
- CDC42,
- MAPK8IP1,
- MAPK8IP2, and
- SH3RF1. | MAP3K11
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Mitogen-activated protein kinase kinase kinase 11 is an enzyme that in humans is encoded by the MAP3K11 gene.[1][2]
# Function
The protein encoded by this gene is called MLK3 and it is a member of the serine/threonine kinase family. This kinase contains a SH3 domain and a leucine zipper-basic motif. This kinase preferentially activates MAPK8/JNK kinase, and functions as a positive regulator of JNK signaling pathway. This kinase can directly phosphorylate, and activates JNK and p38, and is found to be involved in the transcription activity of AP1 mediated by Rho family GTPases and CDC42.[3][4]
# Interactions
MAP3K11 has been shown to interact with:
- AKT1,[5]
- CDC42,[6][7]
- MAPK8IP1,[8]
- MAPK8IP2,[8] and
- SH3RF1.[9] | https://www.wikidoc.org/index.php/MAP3K11 | |
0ddca11f448d54012fb978997f5e1c822d50fd17 | wikidoc | MAP3K12 | MAP3K12
Mitogen-activated protein kinase kinase kinase 12 is an enzyme that in humans is encoded by the MAP3K12 gene.
# Function
The protein encoded by this gene is a member of serine/threonine protein kinase family. This kinase contains a leucine-zipper domain, and is predominately expressed in neuronal cells. The phosphorylation state of this kinase in synaptic terminals was shown to be regulated by membrane depolarization via calcineurin. This kinase forms heterodimers with leucine zipper containing transcription factors, such as cAMP responsive element binding protein (CREB) and MYC, and thus may play a regulatory role in PKA or retinoic acid induced neuronal differentiation.
# Interactions
MAP3K12 has been shown to interact with MAPK8IP1, MAP2K7 and MAPK8IP2.
# Role in Development
MAP3K12, otherwise known as DLK, can initiate coordinated signalling cascades that culminate in the phosphorylation of C-Jun N-terminal kinases or JNK. Several experiments have implicated this interaction as having a role in the developing mammalian nervous system. For example, neuronal migration and axon growth are critical components of neuronal development. DLK null mice have defects in neuronal migration, hypoplasia of several different axonal tracts and reduced axon number in various areas of the brain such as the cingulum and internal capsule. In addition, inhibition of DLK or JNK delays radial migration and disrupts the formation of the neocortex in mice. Another important function of the developing mammalian nervous system is neuronal apoptosis. The absence of DLK also protects cultured mice sensory neurons from apoptosis that would normally be triggered by a lack of NGF. This, among other experiments, heavily implicates it as having a role in neuronal apoptosis.
DLK has several different interactions that contribute to mammalian nervous system development. For axon growth, DLK phosphorylates MAP2K4/7 which then phosphorylates JNK, activating it. In neuronal migration DLK phosphorylates MAP2K4/7 which phosphorylates JNK, and also interacts with JIP which then interacts with MAP2K4/7 and JNK. There is a similar interaction for neuronal apoptosis, where DLK phosphorylates JIP3 and MAP2K7, which both phosphorylate JNK. It is evident then that DLK interactions are a versatile and critical part of neuronal development in mammals. | MAP3K12
Mitogen-activated protein kinase kinase kinase 12 is an enzyme that in humans is encoded by the MAP3K12 gene.[1][2]
# Function
The protein encoded by this gene is a member of serine/threonine protein kinase family. This kinase contains a leucine-zipper domain, and is predominately expressed in neuronal cells. The phosphorylation state of this kinase in synaptic terminals was shown to be regulated by membrane depolarization via calcineurin. This kinase forms heterodimers with leucine zipper containing transcription factors, such as cAMP responsive element binding protein (CREB) and MYC, and thus may play a regulatory role in PKA or retinoic acid induced neuronal differentiation.[2]
# Interactions
MAP3K12 has been shown to interact with MAPK8IP1,[3] MAP2K7[4] and MAPK8IP2.[3]
# Role in Development
MAP3K12, otherwise known as DLK, can initiate coordinated signalling cascades that culminate in the phosphorylation of C-Jun N-terminal kinases or JNK. Several experiments have implicated this interaction as having a role in the developing mammalian nervous system.[5] For example, neuronal migration and axon growth are critical components of neuronal development. DLK null mice have defects in neuronal migration, hypoplasia of several different axonal tracts and reduced axon number in various areas of the brain such as the cingulum and internal capsule.[5] In addition, inhibition of DLK or JNK delays radial migration and disrupts the formation of the neocortex in mice.[5] Another important function of the developing mammalian nervous system is neuronal apoptosis. The absence of DLK also protects cultured mice sensory neurons from apoptosis that would normally be triggered by a lack of NGF.[5] This, among other experiments, heavily implicates it as having a role in neuronal apoptosis.
DLK has several different interactions that contribute to mammalian nervous system development. For axon growth, DLK phosphorylates MAP2K4/7 which then phosphorylates JNK, activating it.[5] In neuronal migration DLK phosphorylates MAP2K4/7 which phosphorylates JNK, and also interacts with JIP which then interacts with MAP2K4/7 and JNK.[5] There is a similar interaction for neuronal apoptosis, where DLK phosphorylates JIP3 and MAP2K7, which both phosphorylate JNK.[5] It is evident then that DLK interactions are a versatile and critical part of neuronal development in mammals. | https://www.wikidoc.org/index.php/MAP3K12 | |
c6e3ce5c1ee503bcc5ff0081d1b9c27de9ed3683 | wikidoc | MEDLINE | MEDLINE
# Overview
MEDLINE (Medical Literature Analysis and Retrieval System Online) is an international literature database of life sciences and biomedical information. It covers the fields of medicine, nursing, pharmacy, dentistry, veterinary medicine, and health care. MEDLINE covers much of the literature in biology and biochemistry, and fields with no direct medical connection, such as molecular evolution. Listing of an article in MEDLINE does not mean endorsement of that article.
Compiled by the U.S. National Library of Medicine (NLM), MEDLINE is freely available on the Internet and searchable via PubMed and NLM's National Center for Biotechnology Information's Entrez system.
# Indexing
MEDLINE uses Medical Subject Headings (MeSH) for information retrieval. Engines designed to search MEDLINE (such as Entrez) generally use a Boolean expressioncombining MeSH terms, words in abstract and title of the article, author names, date of publication, etc. Entrez allows also to find articles similar to a given one based on a mathematical scoring system that takes into account the similarity of word content of the abstracts and titles of two articles.
# Impact
MEDLINE functions as an important resource for biomedical researchers and journal clubs from all over the world. Along with the Cochrane Library and a number of other databases, MEDLINE facilitates evidence-based medicine. Most systematic review articles published nowadays build on extensive searches of MEDLINE to identify articles that might be useful in the review. Many articles mention the terms that have been used to search MEDLINE, so that the search is reproducible by other scientists.
Additionally, MEDLINE influences researchers in their choice of journals in which to publish. Few biomedical researchers today would consider publishing in a journal not indexed by MEDLINE, because then other researchers would not find (and cite) their work.
# Inclusion of journals
Approximately 5,000 of the world's leading biomedical journals are indexed in MEDLINE. Selection is based on the recommendations of a panel, the Literature Selection Technical Review Committee (LSTRC), based on scientific policy and scientific quality. New journals are not included immediately.
PubMed's Journals Database contains information about each included journal, such as official name abbreviation and URL.
# Usage
Searching MEDLINE effectively is a learned skill; untrained users are sometimes frustrated with the large numbers of articles returned by simple searches. Counterintuitively, a search that returns thousands of articles is not guaranteed to be comprehensive.
There are tutorials for instruction on the PubMed interface to MEDLINE. Unlike Google searching of the Web, PubMed searching of MEDLINE requires a little investment of time. Using the MeSH database to define the subject of interest is one of the most useful ways to improve the quality of a search. Using MeSH terms in conjunction with limits (such as publication date or publication type), qualifiers (such as adverse effects or prevention and control), and text-word searching is another. Finding one article on the subject and clicking on the "Related Articles" link to get a collection of similarly classified articles can expand a search that yields few results. In addition to the National Library of Medicine's tutorials, there are several other aids to effective searching, such as pages from a book on MEDLINE usage that can be browsed at Google Book Search.
# Online access
- PubMed
- GoPubMed - Explore PubMed/MEDLINE with Gene Ontology
- EBIMed - Explore PubMed/MEDLINE with Gene Ontology and UniProt
- MeshPubMed - Explore PubMed/MEDLINE with Medical Subject Headings (MeSH)
- Authoratory - a data-mining interface to PubMed showing author's status, most frequent coauthors, professional interests, affiliated institution, etc.
- HubMed - An alternative interface to the PubMed medical literature database.
- eTBLAST - a natural language text similarity engine for MEDLINE and other text databases.
- BIOWIZARD - a Digg-style site for PubMed/MEDLINE with search functionality through Medical Subject Headings (MeSH)
- CureHunter - Explore the relationships between diseases, drugs and therapies in PubMed using the MeSH ontology
- www.medscape.com
- FABLE - a gene-centric text-mining search engine for MEDLINE
- Unbound MEDLINE - Clinician-friendly MEDLINE searcing via PDA, wireless devices and the Web
- PubMed Reader - A free web-based alternative interface for Medline search
- Twease An open-source biomedical search engine (see source distribution). Twease.org searches MEDLINE. Relevance or chronological searches; highlights text passages that match the query; collects and exports references seamlessly to RefWorks, EndNote, BibTex; searches for articles similar to a group of articles; offers a slider to control query expansion with common synonyms, word variants, mesh terms, etc.; content updated weekly; can be downloaded and setup locally to run thousands of searches against Medline. | MEDLINE
# Overview
MEDLINE (Medical Literature Analysis and Retrieval System Online) is an international literature database of life sciences and biomedical information. It covers the fields of medicine, nursing, pharmacy, dentistry, veterinary medicine, and health care. MEDLINE covers much of the literature in biology and biochemistry, and fields with no direct medical connection, such as molecular evolution. Listing of an article in MEDLINE does not mean endorsement of that article.
Compiled by the U.S. National Library of Medicine (NLM), MEDLINE is freely available on the Internet and searchable via PubMed and NLM's National Center for Biotechnology Information's Entrez system.
# Indexing
MEDLINE uses Medical Subject Headings (MeSH) for information retrieval. Engines designed to search MEDLINE (such as Entrez) generally use a Boolean expressioncombining MeSH terms, words in abstract and title of the article, author names, date of publication, etc. Entrez allows also to find articles similar to a given one based on a mathematical scoring system that takes into account the similarity of word content of the abstracts and titles of two articles.
# Impact
MEDLINE functions as an important resource for biomedical researchers and journal clubs from all over the world. Along with the Cochrane Library and a number of other databases, MEDLINE facilitates evidence-based medicine. Most systematic review articles published nowadays build on extensive searches of MEDLINE to identify articles that might be useful in the review. Many articles mention the terms that have been used to search MEDLINE, so that the search is reproducible by other scientists.
Additionally, MEDLINE influences researchers in their choice of journals in which to publish. Few biomedical researchers today would consider publishing in a journal not indexed by MEDLINE, because then other researchers would not find (and cite) their work.
# Inclusion of journals
Approximately 5,000 of the world's leading biomedical journals are indexed in MEDLINE. Selection is based on the recommendations of a panel, the Literature Selection Technical Review Committee (LSTRC), based on scientific policy and scientific quality. New journals are not included immediately.
PubMed's Journals Database [1] contains information about each included journal, such as official name abbreviation and URL.
# Usage
Searching MEDLINE effectively is a learned skill; untrained users are sometimes frustrated with the large numbers of articles returned by simple searches. Counterintuitively, a search that returns thousands of articles is not guaranteed to be comprehensive.
There are tutorials for instruction on the PubMed interface to MEDLINE. Unlike Google searching of the Web, PubMed searching of MEDLINE requires a little investment of time. Using the MeSH database to define the subject of interest is one of the most useful ways to improve the quality of a search. Using MeSH terms in conjunction with limits (such as publication date or publication type), qualifiers (such as adverse effects or prevention and control), and text-word searching is another. Finding one article on the subject and clicking on the "Related Articles" link to get a collection of similarly classified articles can expand a search that yields few results. In addition to the National Library of Medicine's tutorials, there are several other aids to effective searching, such as pages from a book on MEDLINE usage that can be browsed at Google Book Search.
# Online access
- PubMed
- GoPubMed - Explore PubMed/MEDLINE with Gene Ontology
- EBIMed - Explore PubMed/MEDLINE with Gene Ontology and UniProt
- MeshPubMed - Explore PubMed/MEDLINE with Medical Subject Headings (MeSH)
- Authoratory - a data-mining interface to PubMed showing author's status, most frequent coauthors, professional interests, affiliated institution, etc.
- HubMed - An alternative interface to the PubMed medical literature database.
- eTBLAST - a natural language text similarity engine for MEDLINE and other text databases.
- BIOWIZARD - a Digg-style site for PubMed/MEDLINE with search functionality through Medical Subject Headings (MeSH)
- CureHunter - Explore the relationships between diseases, drugs and therapies in PubMed using the MeSH ontology
- www.medscape.com
- FABLE - a gene-centric text-mining search engine for MEDLINE
- Unbound MEDLINE - Clinician-friendly MEDLINE searcing via PDA, wireless devices and the Web
- PubMed Reader - A free web-based alternative interface for Medline search
- Twease An open-source biomedical search engine (see source distribution). Twease.org searches MEDLINE. Relevance or chronological searches; highlights text passages that match the query; collects and exports references seamlessly to RefWorks, EndNote, BibTex; searches for articles similar to a group of articles; offers a slider to control query expansion with common synonyms, word variants, mesh terms, etc.; content updated weekly; can be downloaded and setup locally to run thousands of searches against Medline. | https://www.wikidoc.org/index.php/MEDLINE | |
daa9105dceaba46de785a8723141f2a6c3f60c64 | wikidoc | MPGES-1 | MPGES-1
Microsomal prostaglandin E synthase-1 (mPGES-1) or Prostaglandin E synthase is an enzyme that in humans is encoded by the PTGES gene.
The protein encoded by this gene is a glutathione-dependent prostaglandin E synthase. The expression of this gene has been shown to be induced by proinflammatory cytokine interleukin 1 beta (IL1B). Its expression can also be induced by tumor suppressor protein TP53, and may be involved in TP53-induced apoptosis.
Knockout studies in mice suggest that this gene may contribute to the pathogenesis of collagen-induced arthritis and mediate acute pain during inflammatory responses. | MPGES-1
Microsomal prostaglandin E synthase-1 (mPGES-1)[1][2] or Prostaglandin E synthase is an enzyme that in humans is encoded by the PTGES gene.[3][4][5]
The protein encoded by this gene is a glutathione-dependent prostaglandin E synthase. The expression of this gene has been shown to be induced by proinflammatory cytokine interleukin 1 beta (IL1B). Its expression can also be induced by tumor suppressor protein TP53, and may be involved in TP53-induced apoptosis.
Knockout studies in mice suggest that this gene may contribute to the pathogenesis of collagen-induced arthritis and mediate acute pain during inflammatory responses.[5] | https://www.wikidoc.org/index.php/MPGES-1 | |
cf15f16f32809572e91963137e98093b6f4ebf9e | wikidoc | MPGES-2 | MPGES-2
Microsomal prostaglandin E synthase-2 (mPGES-2) or Prostaglandin E synthase 2 is an enzyme that in humans encoded by the PTGES2 gene located on chromosome 9. The protein encoded by this gene is a membrane-associated prostaglandin E synthase, which catalyzes the conversion of prostaglandin H2 to prostaglandin E2. This protein also has been shown to activate the transcription regulated by a gamma-interferon-activated transcription element (GATE). Multiple transcript variants have been found for this gene.
# Structure
Microsomal prostaglandin E synthase type-2 (mPTGES2) has been crystallized with an anti-inflammatory drug indomethacin (IMN). The N-terminal of mPTGES2 is attached to the lipid membrane and the two hydrophobic pockets connected to form a V shape are located in the bottom of a large cavity for IMN binding. The mPTGES2 exists in a dimer.
# Function
The gene encoding the PTGES2 protein contains 10 exons. The PTGE2 protein encoded by the gene is a 33-kDa membrane-associated prostaglandin E synthase that is thought to be targeted to the Golgi apparatus as well as the mitochondrion within the cell. Prostaglandin E synthase catalyzes the conversion of prostaglandin H2 to prostaglandin E2. The particular reaction catalyzed by PTGE2 is thought to be:
(5Z,13E)-(15S)-9-alpha,11-alpha-epidioxy-15-hydroxyprosta-5,13-dienoate = (5Z,13E)-(15S)-11-alpha,15-dihydroxy-9-oxoprosta-5,13-dienoate.
The PTGE2 protein functions in part of the prostaglandin synthesis pathway, which forms a component of the overall lipid synthesis mechanism in the human body. The activity of PTGES2 is thought to be increased in the presence of sulfhydril coumpounds, in particular dithiothreitol.
The PTGE2 protein also has been shown to activate the transcription regulated by an interferon-gamma gamma-interferon-activated transcription element (GATE).
Model organisms have been used in the study of PTGES2 function. A conditional knockout mouse line, called Ptges2tm1a(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 — at the Wellcome Trust Sanger Institute.
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Twenty two tests were carried out on mutant mice, but no significant abnormalities were observed.
# Clinical significance
The excess production of prostaglandin E 2 is known to contribute to inflammatory diseases which includes rheumatoid arthritis, atherosclerosis, and cancer. Furthermore, naturally occurring polymorphisms of PTGES2 have been shown to be associated with increased risks for diabetes mellitus and metabolic syndromes.
As such, pharmacological inhibition of prostaglandin E 2 production by synthetic minor prenylated chalcones and flavonoids has potential therapeutic viability. It has been shown that the synthesis of prostaglandin E 2 in the endothelial cells of the brain is important for inflammation-induced fever. Additionally, investigators have observed elevations in cell doubling rates for several cancer cell types in the presence of prostaglandin E 2 –producing cell lines. | MPGES-2
Microsomal prostaglandin E synthase-2 (mPGES-2)[1][2] or Prostaglandin E synthase 2 is an enzyme that in humans encoded by the PTGES2 gene located on chromosome 9.[3][4] The protein encoded by this gene is a membrane-associated prostaglandin E synthase, which catalyzes the conversion of prostaglandin H2 to prostaglandin E2. This protein also has been shown to activate the transcription regulated by a gamma-interferon-activated transcription element (GATE). Multiple transcript variants have been found for this gene.[5]
# Structure
Microsomal prostaglandin E synthase type-2 (mPTGES2) has been crystallized with an anti-inflammatory drug indomethacin (IMN).[6] The N-terminal of mPTGES2 is attached to the lipid membrane and the two hydrophobic pockets connected to form a V shape are located in the bottom of a large cavity for IMN binding. The mPTGES2 exists in a dimer.[6]
# Function
The gene encoding the PTGES2 protein contains 10 exons. The PTGE2 protein encoded by the gene is a 33-kDa membrane-associated [7] prostaglandin E synthase that is thought to be targeted to the Golgi apparatus as well as the mitochondrion within the cell. Prostaglandin E synthase catalyzes the conversion of prostaglandin H2 to prostaglandin E2. The particular reaction catalyzed by PTGE2 is thought to be:
(5Z,13E)-(15S)-9-alpha,11-alpha-epidioxy-15-hydroxyprosta-5,13-dienoate = (5Z,13E)-(15S)-11-alpha,15-dihydroxy-9-oxoprosta-5,13-dienoate.[8]
The PTGE2 protein functions in part of the prostaglandin synthesis pathway, which forms a component of the overall lipid synthesis mechanism in the human body. The activity of PTGES2 is thought to be increased in the presence of sulfhydril coumpounds, in particular dithiothreitol.[9]
The PTGE2 protein also has been shown to activate the transcription regulated by an interferon-gamma gamma-interferon-activated transcription element (GATE).[4]
Model organisms have been used in the study of PTGES2 function. A conditional knockout mouse line, called Ptges2tm1a(EUCOMM)Wtsi[14][15] 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 — at the Wellcome Trust Sanger Institute.[16][17][18]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[12][19] Twenty two tests were carried out on mutant mice, but no significant abnormalities were observed.[12]
# Clinical significance
The excess production of prostaglandin E 2 is known to contribute to inflammatory diseases which includes rheumatoid arthritis, atherosclerosis, and cancer.[20][21] Furthermore, naturally occurring polymorphisms of PTGES2 have been shown to be associated with increased risks for diabetes mellitus and metabolic syndromes.[22][23]
As such, pharmacological inhibition of prostaglandin E 2 production by synthetic minor prenylated chalcones and flavonoids has potential therapeutic viability.[20] It has been shown that the synthesis of prostaglandin E 2 in the endothelial cells of the brain is important for inflammation-induced fever.[24] Additionally, investigators have observed elevations in cell doubling rates for several cancer cell types in the presence of prostaglandin E 2 –producing cell lines.[25] | https://www.wikidoc.org/index.php/MPGES-2 | |
c45806fae997a37ec5a6d3acf389bf305c7268a8 | wikidoc | MT-ATP6 | MT-ATP6
MT-ATP6 (or ATP6) is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 6' that encodes the ATP synthase Fo subunit 6 (or subunit/chain A). This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase. This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Mutations in the MT-ATP6 gene have been found in approximately 10 to 20 percent of people with Leigh syndrome.
# Structure
The MT-ATP6 gene provides information for making a protein that is essential for normal mitochondrial function. The human MT-ATP6 gene, located in mitochondrial DNA, is 681 base pairs in length. An unusual feature of MT-ATP6 is the 46-nucleotide gene overlap of its first codons with the end of the MT-ATP8 gene. With respect to the MT-ATP6 reading frame (+3), the MT-ATP8 gene ends in the +1 reading frame with a TAG stop codon.
The MT-ATP6 protein weighs 24.8 kDa and is composed of 226 amino acids. The protein is a subunit of the F1Fo ATPase, also known as Complex V, which consists of 14 nuclear- and 2 mitochondrial-encoded subunits. As an A subunit, MT-ATP6 is contained within the non-catalytic, transmembrane Fo portion of the complex.
The nomenclature of the enzyme has a long history. The F1 fraction derives its name from the term "Fraction 1" and Fo (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally-derived antibiotic that is able to inhibit the Fo unit of ATP synthase. The Fo region of ATP synthase is a proton pore that is embedded in the mitochondrial membrane. It consists of three main subunits A, B, and C, and (in humans) six additional subunits, d, e, f, g, F6, and 8 (or A6L). 3D structure of E. coli homologue of this subunit was modeled based on electron microscopy data (chain M of PDB: 1c17). It forms a transmembrane 4-α-bundle.
# Function
This subunit is a key component of the proton channel, and may play a direct role in the translocation of protons across the membrane. Catalysis in the F1 complex depends upon the rotation of the central stalk and Fo c-ring, which in turn is driven by the flux of protons through the membrane via the interface between the F0 c-ring and subunit A. The peripheral stalk links subunit A to the external surface of the F1 domain, and is thought to act as a stator to counter the tendency of subunit A and the F1alpha3 beta3 catalytic portion to rotate with the central rotary element.
# Clinical significance
Mutations to MT-ATP6 and other genes affecting oxidative phosphorylation in the mitochondria have been associated with a variety of neurodegenerative and cardiovascular disorders, including mitochondrial complex V deficiency, Leber's hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS), Leigh syndrome, and NARP syndrome. Most of the body's cells contain thousands of mitochondria, each with one or more copies of mitochondrial DNA. The severity of some mitochondrial disorders is associated with the percentage of mitochondria in each cell that has a particular genetic change. People with Leigh syndrome due to a MT-ATP6 gene mutation tend to have a very high percentage of mitochondria with the mutation (from more than 90 percent to 95 percent). The less-severe features of NARP result from a lower percentage of mitochondria with the mutation, typically 70 percent to 90 percent. Because these two conditions result from the same genetic changes and can occur in different members of a single family, researchers believe that they may represent a spectrum of overlapping features instead of two distinct syndromes.
## Mitochondrial complex V deficiency
Mitochondrial complex V deficiency is a shortage (deficiency) or loss of function in complex V of the electron transport chain that can cause a wide variety of signs and symptoms affecting many organs and systems of the body, particularly the nervous system and the heart. The disorder can be life-threatening in infancy or early childhood. Affected individuals may have feeding problems, slow growth, low muscle tone (hypotonia), extreme fatigue (lethargy), and developmental delay. They tend to develop elevated levels of lactic acid in the blood (lactic acidosis), which can cause nausea, vomiting, weakness, and rapid breathing. High levels of ammonia in the blood (hyperammonemia) can also occur in affected individuals, and in some cases result in abnormal brain function (encephalopathy) and damage to other organs. Ataxia, microcephaly, developmental delay and intellectual disability have been observed in patients with a frameshift mutation in MT-ATP6. This causes a C insertion at position 8612 that results in a truncated protein only 36 amino acids long, and two T > C single-nucleotide polymorphisms at positions 8610 and 8614 that result in a homopolymeric cytosine stretch.
Another common feature of mitochondrial complex V deficiency is hypertrophic cardiomyopathy. This condition is characterized by thickening (hypertrophy) of the cardiac muscle that can lead to heart failure. The m.8528T>C mutation occurs in the overlapping region of the MT-ATP6 and MT-ATP8 genes and has been described in multiple patients with infantile cardiomyopathy. This mutation changes the initiation codon in MT-ATP6 to threonine as well as a change from tryptophan to arginine at position 55 of MT-ATP8. Individuals with mitochondrial complex V deficiency may also have a characteristic pattern of facial features, including a high forehead, curved eyebrows, outside corners of the eyes that point downward (downslanting palpebral fissures), a prominent bridge of the nose, low-set ears, thin lips, and a small chin (micrognathia).
## Leigh Syndrome
Pathogenic variants of the mitochondrial gene MT-ATP6 are known to cause mtDNA-associated Leigh syndrome, a progressive brain disorder that usually appears in infancy or early childhood. Affected children may experience delayed development, muscle weakness, problems with movement, or difficulty breathing. Other variants known to cause mtDNA-associated Leigh syndrome involve MT-TL1, MT-TK, MT-TW, MT-TV, MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND5, MT-ND6 and MT-CO3. Abnormalities in mitochondrial energy generation result in neurodegenerative disorders like Leigh syndrome, which is characterized by an onset of symptoms between 12 months and three years of age. The symptoms frequently present themselves following a viral infection and include movement disorders and peripheral neuropathy, as well as hypotonia, spasticity and cerebellar ataxia. Roughly half of affected patients die of respiratory or cardiac failure by the age of three. Leigh syndrome is a maternally inherited disorder and its diagnosis is established through genetic testing of the aforementioned mitochondrial genes, including MT-ATP6. MT-ATP6 gene mutations associated with Leigh syndrome change one DNA building block (nucleotide) in the MT-ATP6 gene. The most common genetic change replaces the nucleotide thymine with guanine at position 8993 (written as T8993G). The mutations that cause Leigh syndrome impair the function or stability of the ATP synthase complex, inhibiting ATP production and impairing oxidative phosphorylation. Although the exact mechanism is unclear, researchers believe that impaired oxidative phosphorylation can lead to cell death because of decreased energy available in the cell. Certain tissues that require large amounts of energy, such as the brain, muscles, and heart, seem especially sensitive to decreases in cellular energy. Cell death in the brain likely causes the characteristic changes in the brain seen in Leigh syndrome, which contribute to the signs and symptoms of the condition. Cell death in other sensitive tissues may also contribute to the features of Leigh syndrome. A heteroplasmic T→C MT-ATP6 mutation at position 9185 results in the substitution of a highly conserved leucine to proline at codon 220 and a heteroplasmic T→C missense mutation at position 9191 converted a highly conserved leucine to a proline at position 222 of the polypeptide, leading to a Leigh-type phenotype. The T9185C mutation resulted in a mild and reversible phenotype, with 97% of the patient's muscle and blood samples reflecting the mutation. The T9191C mutation presented a much more severe phenotype that resulted in the death of the patient at 2 years of age.
## NARP syndrome
Some of the mutations of the ATP6 gene that cause Leigh syndrome are also responsible for a similar, but less severe, condition called neuropathy, ataxia, and retinitis pigmentosa (NARP). A small number of mutations in the MT-ATP6 gene have been identified in people with NARP. Each of these mutations changes one nucleotide in the MT-ATP6 gene. As in Leigh syndrome, the most common genetic change associated with NARP replaces the nucleotide thymine with guanine at position 8993 (written as T8993G). The mutations that cause NARP alter the structure or function of ATP synthase, reducing the ability of mitochondria to produce ATP. Although the precise effects of these mutations are unclear, researchers continue to investigate how changes in the MT-ATP6 gene interfere with ATP production and lead to muscle weakness, vision loss, and the other features of NARP.
## Familial bilateral striatal necrosis
A condition called familial bilateral striatal necrosis, which is similar to Leigh syndrome, can also result from changes in the MT-ATP6 gene. In the few reported cases with these mutations, affected children have had delayed development, problems with movement and coordination, weak muscle tone (hypotonia), and an unusually small head size (microcephaly). Researchers have not determined why MT-ATP6 mutations result in this combination of signs and symptoms in children with bilateral striatal necrosis.
# Interactions
MT-ATP6 has been shown to have 20 binary protein-protein interactions including 17 co-complex interactions. MT-ATP6 appears to interact with SP1.
# Research
The SENS Research Foundation have published a paper detailing the successful allotopic expression of replacement DNA for the MT-ATP6 gene in the cell nuclear DNA. | MT-ATP6
MT-ATP6 (or ATP6) is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 6' that encodes the ATP synthase Fo subunit 6 (or subunit/chain A). This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase.[1] This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Mutations in the MT-ATP6 gene have been found in approximately 10 to 20 percent of people with Leigh syndrome.[2]
# Structure
The MT-ATP6 gene provides information for making a protein that is essential for normal mitochondrial function. The human MT-ATP6 gene, located in mitochondrial DNA, is 681 base pairs in length.[3] An unusual feature of MT-ATP6 is the 46-nucleotide gene overlap of its first codons with the end of the MT-ATP8 gene. With respect to the MT-ATP6 reading frame (+3), the MT-ATP8 gene ends in the +1 reading frame with a TAG stop codon.
The MT-ATP6 protein weighs 24.8 kDa and is composed of 226 amino acids.[4][5] The protein is a subunit of the F1Fo ATPase, also known as Complex V, which consists of 14 nuclear- and 2 mitochondrial-encoded subunits. As an A subunit, MT-ATP6 is contained within the non-catalytic, transmembrane Fo portion of the complex.[3]
The nomenclature of the enzyme has a long history. The F1 fraction derives its name from the term "Fraction 1" and Fo (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally-derived antibiotic that is able to inhibit the Fo unit of ATP synthase.[6][7] The Fo region of ATP synthase is a proton pore that is embedded in the mitochondrial membrane. It consists of three main subunits A, B, and C, and (in humans) six additional subunits, d, e, f, g, F6, and 8 (or A6L). 3D structure of E. coli homologue of this subunit was modeled based on electron microscopy data (chain M of PDB: 1c17). It forms a transmembrane 4-α-bundle.
# Function
This subunit is a key component of the proton channel, and may play a direct role in the translocation of protons across the membrane. Catalysis in the F1 complex depends upon the rotation of the central stalk and Fo c-ring, which in turn is driven by the flux of protons through the membrane via the interface between the F0 c-ring and subunit A. The peripheral stalk links subunit A to the external surface of the F1 domain, and is thought to act as a stator to counter the tendency of subunit A and the F1alpha3 beta3 catalytic portion to rotate with the central rotary element.[8]
# Clinical significance
Mutations to MT-ATP6 and other genes affecting oxidative phosphorylation in the mitochondria have been associated with a variety of neurodegenerative and cardiovascular disorders, including mitochondrial complex V deficiency, Leber's hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS), Leigh syndrome, and NARP syndrome. Most of the body's cells contain thousands of mitochondria, each with one or more copies of mitochondrial DNA. The severity of some mitochondrial disorders is associated with the percentage of mitochondria in each cell that has a particular genetic change. People with Leigh syndrome due to a MT-ATP6 gene mutation tend to have a very high percentage of mitochondria with the mutation (from more than 90 percent to 95 percent). The less-severe features of NARP result from a lower percentage of mitochondria with the mutation, typically 70 percent to 90 percent. Because these two conditions result from the same genetic changes and can occur in different members of a single family, researchers believe that they may represent a spectrum of overlapping features instead of two distinct syndromes.[2]
## Mitochondrial complex V deficiency
Mitochondrial complex V deficiency is a shortage (deficiency) or loss of function in complex V of the electron transport chain that can cause a wide variety of signs and symptoms affecting many organs and systems of the body, particularly the nervous system and the heart. The disorder can be life-threatening in infancy or early childhood. Affected individuals may have feeding problems, slow growth, low muscle tone (hypotonia), extreme fatigue (lethargy), and developmental delay. They tend to develop elevated levels of lactic acid in the blood (lactic acidosis), which can cause nausea, vomiting, weakness, and rapid breathing. High levels of ammonia in the blood (hyperammonemia) can also occur in affected individuals, and in some cases result in abnormal brain function (encephalopathy) and damage to other organs.[9] Ataxia, microcephaly, developmental delay and intellectual disability have been observed in patients with a frameshift mutation in MT-ATP6. This causes a C insertion at position 8612 that results in a truncated protein only 36 amino acids long, and two T > C single-nucleotide polymorphisms at positions 8610 and 8614 that result in a homopolymeric cytosine stretch.[10]
Another common feature of mitochondrial complex V deficiency is hypertrophic cardiomyopathy. This condition is characterized by thickening (hypertrophy) of the cardiac muscle that can lead to heart failure.[9] The m.8528T>C mutation occurs in the overlapping region of the MT-ATP6 and MT-ATP8 genes and has been described in multiple patients with infantile cardiomyopathy. This mutation changes the initiation codon in MT-ATP6 to threonine as well as a change from tryptophan to arginine at position 55 of MT-ATP8.[11][12] Individuals with mitochondrial complex V deficiency may also have a characteristic pattern of facial features, including a high forehead, curved eyebrows, outside corners of the eyes that point downward (downslanting palpebral fissures), a prominent bridge of the nose, low-set ears, thin lips, and a small chin (micrognathia).[9]
## Leigh Syndrome
Pathogenic variants of the mitochondrial gene MT-ATP6 are known to cause mtDNA-associated Leigh syndrome, a progressive brain disorder that usually appears in infancy or early childhood. Affected children may experience delayed development, muscle weakness, problems with movement, or difficulty breathing.[2] Other variants known to cause mtDNA-associated Leigh syndrome involve MT-TL1, MT-TK, MT-TW, MT-TV, MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND5, MT-ND6 and MT-CO3. Abnormalities in mitochondrial energy generation result in neurodegenerative disorders like Leigh syndrome, which is characterized by an onset of symptoms between 12 months and three years of age. The symptoms frequently present themselves following a viral infection and include movement disorders and peripheral neuropathy, as well as hypotonia, spasticity and cerebellar ataxia. Roughly half of affected patients die of respiratory or cardiac failure by the age of three. Leigh syndrome is a maternally inherited disorder and its diagnosis is established through genetic testing of the aforementioned mitochondrial genes, including MT-ATP6.[13] MT-ATP6 gene mutations associated with Leigh syndrome change one DNA building block (nucleotide) in the MT-ATP6 gene. The most common genetic change replaces the nucleotide thymine with guanine at position 8993 (written as T8993G). The mutations that cause Leigh syndrome impair the function or stability of the ATP synthase complex, inhibiting ATP production and impairing oxidative phosphorylation. Although the exact mechanism is unclear, researchers believe that impaired oxidative phosphorylation can lead to cell death because of decreased energy available in the cell. Certain tissues that require large amounts of energy, such as the brain, muscles, and heart, seem especially sensitive to decreases in cellular energy. Cell death in the brain likely causes the characteristic changes in the brain seen in Leigh syndrome, which contribute to the signs and symptoms of the condition. Cell death in other sensitive tissues may also contribute to the features of Leigh syndrome. A heteroplasmic T→C MT-ATP6 mutation at position 9185 results in the substitution of a highly conserved leucine to proline at codon 220 and a heteroplasmic T→C missense mutation at position 9191 converted a highly conserved leucine to a proline at position 222 of the polypeptide, leading to a Leigh-type phenotype. The T9185C mutation resulted in a mild and reversible phenotype, with 97% of the patient's muscle and blood samples reflecting the mutation. The T9191C mutation presented a much more severe phenotype that resulted in the death of the patient at 2 years of age.[14]
## NARP syndrome
Some of the mutations of the ATP6 gene that cause Leigh syndrome are also responsible for a similar, but less severe, condition called neuropathy, ataxia, and retinitis pigmentosa (NARP).[15] A small number of mutations in the MT-ATP6 gene have been identified in people with NARP. Each of these mutations changes one nucleotide in the MT-ATP6 gene. As in Leigh syndrome, the most common genetic change associated with NARP replaces the nucleotide thymine with guanine at position 8993 (written as T8993G). The mutations that cause NARP alter the structure or function of ATP synthase, reducing the ability of mitochondria to produce ATP. Although the precise effects of these mutations are unclear, researchers continue to investigate how changes in the MT-ATP6 gene interfere with ATP production and lead to muscle weakness, vision loss, and the other features of NARP.[2]
## Familial bilateral striatal necrosis
A condition called familial bilateral striatal necrosis, which is similar to Leigh syndrome, can also result from changes in the MT-ATP6 gene. In the few reported cases with these mutations, affected children have had delayed development, problems with movement and coordination, weak muscle tone (hypotonia), and an unusually small head size (microcephaly). Researchers have not determined why MT-ATP6 mutations result in this combination of signs and symptoms in children with bilateral striatal necrosis.[2]
# Interactions
MT-ATP6 has been shown to have 20 binary protein-protein interactions including 17 co-complex interactions. MT-ATP6 appears to interact with SP1.[16]
# Research
The SENS Research Foundation have published a paper detailing the successful allotopic expression of replacement DNA for the MT-ATP6 gene in the cell nuclear DNA.[17] | https://www.wikidoc.org/index.php/MT-ATP6 | |
87ae983a91d7dd8099761da6e7bbc41529ae672d | wikidoc | MT-ATP8 | MT-ATP8
MT-ATP8 (or ATP8) is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 8' that encodes a subunit of mitochondrial ATP synthase, ATP synthase Fo subunit 8 (or subunit A6L). This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase. This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP. Subunit 8 differs in sequence between Metazoa, plants and Fungi.
# Structure
The ATP synthase protein 8 of human and other mammals is encoded in the mitochondrial genome by the MT-ATP8 gene. When the complete human mitochondrial genome was first published, the MT-ATP8 gene was described as the unidentified reading frame URF A6L. An unusual feature of the MT-ATP8 gene is its 46-nucleotide overlap with the MT-ATP6 gene. With respect to the reading frame (+1) of MT-ATP8, the MT-ATP6 gene starts on the +3 reading frame.
The MT-ATP8 protein weighs 8 kDa and is composed of 68 amino acids. The protein is a subunit of the F1Fo ATPase, also known as Complex V, which consists of 14 nuclear- and 2 mitochondrial-encoded subunits. F-type ATPases consist of two structural domains, F1 containing the extramembraneous catalytic core and Fo containing the membrane proton channel, linked together by a central stalk and a peripheral stalk. As an A subunit, MT-ATP8 is contained within the non-catalytic, transmembrane Fo portion of the complex, comprising the proton channel. The catalytic portion of mitochondrial ATP synthase consists of 5 different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alpha, 3 beta, and a single representative of the other 3. The proton channel consists of three main subunits (a, b, c). This gene encodes the delta subunit of the catalytic core. Alternatively spliced transcript variants encoding the same isoform have been identified.
# Function
The MT-ATP8 gene encodes a subunit of mitochondrial ATP synthase, located within the thylakoid membrane and the inner mitochondrial membrane. Mitochondrial ATP synthase catalyzes ATP synthesis, utilizing an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation. The Fo region causes rotation of F1, which has a water-soluble component that hydrolyzes ATP and together, the F1Fo creates a pathway for movement of protons across the membrane.
This protein subunit appears to be an integral component of the stator stalk in yeast mitochondrial F-ATPases. The stator stalk is anchored in the membrane, and acts to prevent futile rotation of the ATPase subunits relative to the rotor during coupled ATP synthesis/hydrolysis. This subunit may have an analogous function in Metazoa.
# Nomenclature
The nomenclature of the enzyme has a long history. The F1 fraction derives its name from the term "Fraction 1" and Fo (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally-derived antibiotic that is able to inhibit the Fo unit of ATP synthase. The Fo region of ATP synthase is a proton pore that is embedded in the mitochondrial membrane. It consists of three main subunits A, B, and C, and (in humans) six additional subunits, d, e, f, g, MT-ATP6 (or F6), and MT-ATP8 (or A6L). 3D structure of E. coli homologue of this subunit was modeled based on electron microscopy data (chain M of PDB: 1c17). It forms a transmembrane 4-α-bundle.
# Clinical Significance
Mutations to MT-ATP8 and other genes affecting oxidative phosphorylation in the mitochondria have been associated with a variety of neurodegenerative and cardiovascular disorders, including mitochondrial complex V deficiency, Leber's hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS), Leigh syndrome, and NARP syndrome. Most of the body's cells contain thousands of mitochondria, each with one or more copies of mitochondrial DNA. The severity of some mitochondrial disorders is associated with the percentage of mitochondria in each cell that has a particular genetic change. People with Leigh syndrome due to a MT-ATP6 gene mutation tend to have a very high percentage of mitochondria with the mutation (from more than 90 percent to 95 percent). The less-severe features of NARP result from a lower percentage of mitochondria with the mutation, typically 70 percent to 90 percent. Because these two conditions result from the same genetic changes and can occur in different members of a single family, researchers believe that they may represent a spectrum of overlapping features instead of two distinct syndromes.
Mitochondrial complex V deficiency presents with heterogeneous clinical manifestations including neuropathy, ataxia, hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy can present with negligible to extreme hypertrophy, minimal to extensive fibrosis and myocyte disarray, absent to severe left ventricular outflow tract obstruction, and distinct septal contours/morphologies with extremely varying clinical course.
Mitochondrial complex V deficiency is a shortage (deficiency) or loss of function in complex V of the electron transport chain that can cause a wide variety of signs and symptoms affecting many organs and systems of the body, particularly the nervous system and the heart. The disorder can be life-threatening in infancy or early childhood. Affected individuals may have feeding problems, slow growth, low muscle tone (hypotonia), extreme fatigue (lethargy), and developmental delay. They tend to develop elevated levels of lactic acid in the blood (lactic acidosis), which can cause nausea, vomiting, weakness, and rapid breathing. High levels of ammonia in the blood (hyperammonemia) can also occur in affected individuals, and in some cases result in abnormal brain function (encephalopathy) and damage to other organs. Ataxia, microcephaly, developmental delay and intellectual disability have been observed in patients with a frameshift mutation in MT-ATP6. This causes a C insertion at position 8612 that results in a truncated protein only 36 amino acids long, and two T > C single-nucleotide polymorphisms at positions 8610 and 8614 that result in a homopolymeric cytosine stretch.
Hypertrophic cardiomyopathy, a common feature of mitochondrial complex V deficiency, is characterized by thickening (hypertrophy) of the cardiac muscle that can lead to heart failure. The m.8528T>C mutation occurs in the overlapping region of the MT-ATP6 and MT-ATP8 genes and has been described in multiple patients with infantile cardiomyopathy. This mutation changes the initiation codon in MT-ATP6 to threonine as well as a change from tryptophan to arginine at position 55 of MT-ATP8. Individuals with mitochondrial complex V deficiency may also have a characteristic pattern of facial features, including a high forehead, curved eyebrows, outside corners of the eyes that point downward (downslanting palpebral fissures), a prominent bridge of the nose, low-set ears, thin lips, and a small chin (micrognathia).
Infantile hypertrophic cardiomyopathy (CMHI) is also caused by mutations affecting distinct genetic loci, including MT-ATP6 and MT-ATP8. An infantile form of hypertrophic cardiomyopathy, a heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death. | MT-ATP8
MT-ATP8 (or ATP8) is a mitochondrial gene with the full name 'mitochondrially encoded ATP synthase membrane subunit 8' that encodes a subunit of mitochondrial ATP synthase, ATP synthase Fo subunit 8 (or subunit A6L). This subunit belongs to the Fo complex of the large, transmembrane F-type ATP synthase.[1] This enzyme, which is also known as complex V, is responsible for the final step of oxidative phosphorylation in the electron transport chain. Specifically, one segment of ATP synthase allows positively charged ions, called protons, to flow across a specialized membrane inside mitochondria. Another segment of the enzyme uses the energy created by this proton flow to convert a molecule called adenosine diphosphate (ADP) to ATP.[2] Subunit 8 differs in sequence between Metazoa, plants and Fungi.
# Structure
The ATP synthase protein 8 of human and other mammals is encoded in the mitochondrial genome by the MT-ATP8 gene. When the complete human mitochondrial genome was first published, the MT-ATP8 gene was described as the unidentified reading frame URF A6L.[1] An unusual feature of the MT-ATP8 gene is its 46-nucleotide overlap with the MT-ATP6 gene. With respect to the reading frame (+1) of MT-ATP8, the MT-ATP6 gene starts on the +3 reading frame.
The MT-ATP8 protein weighs 8 kDa and is composed of 68 amino acids.[3][4] The protein is a subunit of the F1Fo ATPase, also known as Complex V, which consists of 14 nuclear- and 2 mitochondrial-encoded subunits. F-type ATPases consist of two structural domains, F1 containing the extramembraneous catalytic core and Fo containing the membrane proton channel, linked together by a central stalk and a peripheral stalk. As an A subunit, MT-ATP8 is contained within the non-catalytic, transmembrane Fo portion of the complex, comprising the proton channel. The catalytic portion of mitochondrial ATP synthase consists of 5 different subunits (alpha, beta, gamma, delta, and epsilon) assembled with a stoichiometry of 3 alpha, 3 beta, and a single representative of the other 3. The proton channel consists of three main subunits (a, b, c). This gene encodes the delta subunit of the catalytic core. Alternatively spliced transcript variants encoding the same isoform have been identified.[5][2]
# Function
The MT-ATP8 gene encodes a subunit of mitochondrial ATP synthase, located within the thylakoid membrane and the inner mitochondrial membrane. Mitochondrial ATP synthase catalyzes ATP synthesis, utilizing an electrochemical gradient of protons across the inner membrane during oxidative phosphorylation.[5] The Fo region causes rotation of F1, which has a water-soluble component that hydrolyzes ATP and together, the F1Fo creates a pathway for movement of protons across the membrane.[6]
This protein subunit appears to be an integral component of the stator stalk in yeast mitochondrial F-ATPases.[7] The stator stalk is anchored in the membrane, and acts to prevent futile rotation of the ATPase subunits relative to the rotor during coupled ATP synthesis/hydrolysis. This subunit may have an analogous function in Metazoa.
# Nomenclature
The nomenclature of the enzyme has a long history. The F1 fraction derives its name from the term "Fraction 1" and Fo (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally-derived antibiotic that is able to inhibit the Fo unit of ATP synthase.[8][9] The Fo region of ATP synthase is a proton pore that is embedded in the mitochondrial membrane. It consists of three main subunits A, B, and C, and (in humans) six additional subunits, d, e, f, g, MT-ATP6 (or F6), and MT-ATP8 (or A6L). 3D structure of E. coli homologue of this subunit was modeled based on electron microscopy data (chain M of PDB: 1c17). It forms a transmembrane 4-α-bundle.
# Clinical Significance
Mutations to MT-ATP8 and other genes affecting oxidative phosphorylation in the mitochondria have been associated with a variety of neurodegenerative and cardiovascular disorders, including mitochondrial complex V deficiency, Leber's hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy with stroke-like episodes (MELAS), Leigh syndrome, and NARP syndrome. Most of the body's cells contain thousands of mitochondria, each with one or more copies of mitochondrial DNA. The severity of some mitochondrial disorders is associated with the percentage of mitochondria in each cell that has a particular genetic change. People with Leigh syndrome due to a MT-ATP6 gene mutation tend to have a very high percentage of mitochondria with the mutation (from more than 90 percent to 95 percent). The less-severe features of NARP result from a lower percentage of mitochondria with the mutation, typically 70 percent to 90 percent. Because these two conditions result from the same genetic changes and can occur in different members of a single family, researchers believe that they may represent a spectrum of overlapping features instead of two distinct syndromes.[2]
Mitochondrial complex V deficiency presents with heterogeneous clinical manifestations including neuropathy, ataxia, hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy can present with negligible to extreme hypertrophy, minimal to extensive fibrosis and myocyte disarray, absent to severe left ventricular outflow tract obstruction, and distinct septal contours/morphologies with extremely varying clinical course.[10][11]
Mitochondrial complex V deficiency is a shortage (deficiency) or loss of function in complex V of the electron transport chain that can cause a wide variety of signs and symptoms affecting many organs and systems of the body, particularly the nervous system and the heart. The disorder can be life-threatening in infancy or early childhood. Affected individuals may have feeding problems, slow growth, low muscle tone (hypotonia), extreme fatigue (lethargy), and developmental delay. They tend to develop elevated levels of lactic acid in the blood (lactic acidosis), which can cause nausea, vomiting, weakness, and rapid breathing. High levels of ammonia in the blood (hyperammonemia) can also occur in affected individuals, and in some cases result in abnormal brain function (encephalopathy) and damage to other organs.[12] Ataxia, microcephaly, developmental delay and intellectual disability have been observed in patients with a frameshift mutation in MT-ATP6. This causes a C insertion at position 8612 that results in a truncated protein only 36 amino acids long, and two T > C single-nucleotide polymorphisms at positions 8610 and 8614 that result in a homopolymeric cytosine stretch.[13]
Hypertrophic cardiomyopathy, a common feature of mitochondrial complex V deficiency, is characterized by thickening (hypertrophy) of the cardiac muscle that can lead to heart failure.[12] The m.8528T>C mutation occurs in the overlapping region of the MT-ATP6 and MT-ATP8 genes and has been described in multiple patients with infantile cardiomyopathy. This mutation changes the initiation codon in MT-ATP6 to threonine as well as a change from tryptophan to arginine at position 55 of MT-ATP8.[14][11] Individuals with mitochondrial complex V deficiency may also have a characteristic pattern of facial features, including a high forehead, curved eyebrows, outside corners of the eyes that point downward (downslanting palpebral fissures), a prominent bridge of the nose, low-set ears, thin lips, and a small chin (micrognathia).[12]
Infantile hypertrophic cardiomyopathy (CMHI) is also caused by mutations affecting distinct genetic loci, including MT-ATP6 and MT-ATP8. An infantile form of hypertrophic cardiomyopathy, a heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death.[10][11] | https://www.wikidoc.org/index.php/MT-ATP8 | |
08a24ee98bd377c6e5d93fb731fb131040573953 | wikidoc | MT-ND4L | MT-ND4L
NADH-ubiquinone oxidoreductase chain 4L is a protein that in humans is encoded by the mitochondrial gene MT-ND4L. The ND4L protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variants of MT-ND4L are associated with increased BMI in adults and Leber's Hereditary Optic Neuropathy (LHON).
# Structure
The MT-ND4L gene is located in human mitochondrial DNA from base pair 10,469 to 10,765. An unusual feature of the human MT-ND4L gene is the 7-nucleotide gene overlap of its last three codons (5'-CAA TGC TAA-3' coding for Gln, Cys and Stop) with the first three codons of the MT-ND4 gene (5'-ATG CTA AAA-3' coding for amino acids Met-Leu-Lys). With respect to the MT-ND4L reading frame (+1), the MT-ND4 gene starts in the +3 reading frame: AA versus CA.
The MT-ND4L gene produces an 11 kDa protein composed of 98 amino acids. MT-ND4L is one of seven mitochondrially-encoded subunits of the enzyme NADH dehydrogenase (ubiquinone). Also known as Complex I, it is the largest of the respiratory complexes. The structure is L-shaped with a long, hydrophobic transmembrane domain and a hydrophilic domain for the peripheral arm that includes all the known redox centres and the NADH binding site. MT-ND4L and the rest of the mitochondrially encoded subunits are the most hydrophobic of the subunits of Complex I and form the core of the transmembrane region.
# Function
MT-ND4L is a subunit of the respiratory chain Complex I that is believed to belong to the minimal assembly of core proteins required to catalyze NADH dehydrogenation and electron transfer to ubiquinone (coenzyme Q10). Initially, NADH binds to Complex I and transfers two electrons to the isoalloxazine ring of the flavin mononucleotide (FMN) prosthetic arm to form FMNH2. The electrons are transferred through a series of iron-sulfur (Fe-S) clusters in the prosthetic arm and finally to coenzyme Q10 (CoQ), which is reduced to ubiquinol (CoQH2). The flow of electrons changes the redox state of the protein, resulting in a conformational change and pK shift of the ionizable side chain, which pumps four hydrogen ions out of the mitochondrial matrix.
# Clinical significance
Mitochondrial dysfunction resulting from variants of MT-ND4L, MT-ND1 and MT-ND2 have been linked to BMI in adults and implicated in metabolic disorders including obesity, diabetes and hypertension.
A T>C mutation at position 10,663 in the mitochondrial gene MT-ND4L is known to cause Leber's Hereditary Optic Neuropathy (LHON). This mutation results in the replacement of the amino acid valine with alanine at position 65 of the protein ND4L, disrupting function of Complex I in the electron transport chain. It is unknown how this mutation leads to the loss of vision in LHON patients, but it may interrupt ATP production due to the impaired activity of Complex I. Mutations in other genes encoding subunits of Complex I, including MT-ND1, MT-ND2, MT-ND4, MT-ND5, and MT-ND6 are also known to cause LHON. | MT-ND4L
NADH-ubiquinone oxidoreductase chain 4L is a protein that in humans is encoded by the mitochondrial gene MT-ND4L.[1] The ND4L protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.[2] Variants of MT-ND4L are associated with increased BMI in adults and Leber's Hereditary Optic Neuropathy (LHON).[3][4]
# Structure
The MT-ND4L gene is located in human mitochondrial DNA from base pair 10,469 to 10,765.[1][5] An unusual feature of the human MT-ND4L gene is the 7-nucleotide gene overlap of its last three codons (5'-CAA TGC TAA-3' coding for Gln, Cys and Stop) with the first three codons of the MT-ND4 gene (5'-ATG CTA AAA-3' coding for amino acids Met-Leu-Lys).[5] With respect to the MT-ND4L reading frame (+1), the MT-ND4 gene starts in the +3 reading frame: [CAA][TGC][TAA]AA versus CA[ATG][CTA][AAA].
The MT-ND4L gene produces an 11 kDa protein composed of 98 amino acids.[6][7] MT-ND4L is one of seven mitochondrially-encoded subunits of the enzyme NADH dehydrogenase (ubiquinone). Also known as Complex I, it is the largest of the respiratory complexes. The structure is L-shaped with a long, hydrophobic transmembrane domain and a hydrophilic domain for the peripheral arm that includes all the known redox centres and the NADH binding site. MT-ND4L and the rest of the mitochondrially encoded subunits are the most hydrophobic of the subunits of Complex I and form the core of the transmembrane region.[2]
# Function
MT-ND4L is a subunit of the respiratory chain Complex I that is believed to belong to the minimal assembly of core proteins required to catalyze NADH dehydrogenation and electron transfer to ubiquinone (coenzyme Q10).[8] Initially, NADH binds to Complex I and transfers two electrons to the isoalloxazine ring of the flavin mononucleotide (FMN) prosthetic arm to form FMNH2. The electrons are transferred through a series of iron-sulfur (Fe-S) clusters in the prosthetic arm and finally to coenzyme Q10 (CoQ), which is reduced to ubiquinol (CoQH2). The flow of electrons changes the redox state of the protein, resulting in a conformational change and pK shift of the ionizable side chain, which pumps four hydrogen ions out of the mitochondrial matrix.[2]
# Clinical significance
Mitochondrial dysfunction resulting from variants of MT-ND4L, MT-ND1 and MT-ND2 have been linked to BMI in adults and implicated in metabolic disorders including obesity, diabetes and hypertension.[3]
A T>C mutation at position 10,663 in the mitochondrial gene MT-ND4L is known to cause Leber's Hereditary Optic Neuropathy (LHON). This mutation results in the replacement of the amino acid valine with alanine at position 65 of the protein ND4L, disrupting function of Complex I in the electron transport chain. It is unknown how this mutation leads to the loss of vision in LHON patients, but it may interrupt ATP production due to the impaired activity of Complex I. Mutations in other genes encoding subunits of Complex I, including MT-ND1, MT-ND2, MT-ND4, MT-ND5, and MT-ND6 are also known to cause LHON.[4] | https://www.wikidoc.org/index.php/MT-ND4L | |
69e2ac413fe88b0ff9d76aeaa2b6d535bc76fc96 | wikidoc | MT-RNR1 | MT-RNR1
Mitochondrially encoded 12S ribosomal RNA (often abbreviated as 12S or 12S rRNA), also known as Mitochondrial-derived peptide MOTS-c or Mitochondrial open reading frame of the 12S rRNA-c is a component of the small subunit (SSU) of the mitochondrial ribosome. In humans, 12S is encoded by the MT-RNR1 gene and is 959 nucleotides long. MT-RNR1 is one of the 37 genes contained in animal mitochondria genomes. Their 2 rRNA, 22 tRNA and 13 mRNA genes are very useful in phylogenetic studies, in particular the 12S and 16S rRNAs. The 12S rRNA is the mitochondrial homologue of the prokaryotic 16S and eukaryotic nuclear 18S ribosomal RNAs. Mutations in the MT-RNR1 gene may be associated with hearing loss.
# Structure
The MT-RNR1 gene is located on the p arm of the mitochondrial DNA at position 12 and it spans 953 base pairs.
# Function
The MT-RNR1 gene encodes for a protein responsible for regulating insulin sensitivity and metabolic homeostasis. The protein acts as an inhibitor of the folate cycle, thereby reducing de novo purine biosynthesis which leads to the accumulation of the de novo purine synthesis intermediate 5-aminoimidazole-4-carboxamide (AICAR) and the activation of the metabolic regulator 5'-AMP-activated protein kinase (AMPK). The protein also protects against age-dependent and diet-induced insulin resistance as well as diet-induced obesity.
# Clinical significance
## Nonsyndromic Hearing Loss and Deafness, Mitochondrial
Pathogenic mutations in the MT-RNR1 gene have been found to cause late-onset Mitochondrial Nonsyndromic Hearing Loss and Deafness with predisposed aminoglycoside ototoxicities. Nonsyndromic Deafness is characterized by a partial or total sensorineural hearing loss (SNHL) of variable onset and severity that is not associated with other signs and symptoms. Most forms of nonsyndromic deafness are associated with permanent hearing loss caused by damage to structures in the inner ear.
Mutations of 1494C>T, 1555A>G, and 1095T>C in the MT-RNR1 gene have been identified to cause the hearing loss.
## Complex IV Deficiency
MT-RNR1 mutations have been associated with complex IV deficiency of the mitochondrial respiratory chain, also known as the cytochrome c oxidase deficiency. Cytochrome c oxidase deficiency is a rare genetic condition that can affect multiple parts of the body, including skeletal muscles, the heart, the brain, or the liver. Common clinical manifestations include myopathy, hypotonia, and encephalomyopathy, lactic acidosis, and hypertrophic cardiomyopathy. A 9952G>A mutation was found in a patient with the deficiency. | MT-RNR1
Mitochondrially encoded 12S ribosomal RNA (often abbreviated as 12S or 12S rRNA), also known as Mitochondrial-derived peptide MOTS-c or Mitochondrial open reading frame of the 12S rRNA-c is a component of the small subunit (SSU) of the mitochondrial ribosome. In humans, 12S is encoded by the MT-RNR1 gene and is 959 nucleotides long.[1][2][3] MT-RNR1 is one of the 37 genes contained in animal mitochondria genomes. Their 2 rRNA, 22 tRNA and 13 mRNA genes are very useful in phylogenetic studies, in particular the 12S and 16S rRNAs. The 12S rRNA is the mitochondrial homologue of the prokaryotic 16S and eukaryotic nuclear 18S ribosomal RNAs.[4] Mutations in the MT-RNR1 gene may be associated with hearing loss.[5]
# Structure
The MT-RNR1 gene is located on the p arm of the mitochondrial DNA at position 12 and it spans 953 base pairs.[6]
# Function
The MT-RNR1 gene encodes for a protein responsible for regulating insulin sensitivity and metabolic homeostasis. The protein acts as an inhibitor of the folate cycle, thereby reducing de novo purine biosynthesis which leads to the accumulation of the de novo purine synthesis intermediate 5-aminoimidazole-4-carboxamide (AICAR) and the activation of the metabolic regulator 5'-AMP-activated protein kinase (AMPK). The protein also protects against age-dependent and diet-induced insulin resistance as well as diet-induced obesity.[3][2]
# Clinical significance
## Nonsyndromic Hearing Loss and Deafness, Mitochondrial
Pathogenic mutations in the MT-RNR1 gene have been found to cause late-onset Mitochondrial Nonsyndromic Hearing Loss and Deafness with predisposed aminoglycoside ototoxicities.[7] Nonsyndromic Deafness is characterized by a partial or total sensorineural hearing loss (SNHL) of variable onset and severity that is not associated with other signs and symptoms.[8] Most forms of nonsyndromic deafness are associated with permanent hearing loss caused by damage to structures in the inner ear.[2][3]
Mutations of 1494C>T, 1555A>G, and 1095T>C in the MT-RNR1 gene have been identified to cause the hearing loss.[9][10][11]
## Complex IV Deficiency
MT-RNR1 mutations have been associated with complex IV deficiency of the mitochondrial respiratory chain, also known as the cytochrome c oxidase deficiency. Cytochrome c oxidase deficiency is a rare genetic condition that can affect multiple parts of the body, including skeletal muscles, the heart, the brain, or the liver. Common clinical manifestations include myopathy, hypotonia, and encephalomyopathy, lactic acidosis, and hypertrophic cardiomyopathy.[12] A 9952G>A mutation was found in a patient with the deficiency.[13] | https://www.wikidoc.org/index.php/MT-RNR1 | |
8e5d0e6f4e54abdf4836356879ba8476f682c9ae | wikidoc | MTHFD1L | MTHFD1L
Monofunctional C1-tetrahydrofolate synthase, mitochondrial also known as formyltetrahydrofolate synthetase, is an enzyme that in humans is encoded by the MTHFD1L gene (methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1-like).
# Function
One-carbon substituted forms of tetrahydrofolate (THF) are involved in the de novo synthesis of purines and thymidylate and support cellular methylation reactions through the regeneration of methionine from homocysteine. MTHFD1L is an enzyme involved in THF synthesis in mitochondria.
In contrast to MTHFD1 that has trifunctional methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase, and formyltetrahydrofolate synthetase enzymatic activities, MTHFD1L only has formyltetrahydrofolate synthetase activity.
# Clinical significance
Certain variants of the MTHFD1L are associated neural tube defects.
# Model organisms
Model organisms have been used in the study of MTHFD1L function. A conditional knockout mouse line, called Mthfd1ltm1a(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 six tests were carried out on mutant mice and two significant abnormalities were observed. The homozygous mutant embryos identified during gestation had exencephaly. None survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice and no further abnormalities were observed. | MTHFD1L
Monofunctional C1-tetrahydrofolate synthase, mitochondrial also known as formyltetrahydrofolate synthetase, is an enzyme that in humans is encoded by the MTHFD1L gene (methylenetetrahydrofolate dehydrogenase (NADP+ dependent) 1-like).[1][2][3]
# Function
One-carbon substituted forms of tetrahydrofolate (THF) are involved in the de novo synthesis of purines and thymidylate and support cellular methylation reactions through the regeneration of methionine from homocysteine. MTHFD1L is an enzyme involved in THF synthesis in mitochondria.[3]
In contrast to MTHFD1 that has trifunctional methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase, and formyltetrahydrofolate synthetase enzymatic activities, MTHFD1L only has formyltetrahydrofolate synthetase activity.[4]
# Clinical significance
Certain variants of the MTHFD1L are associated neural tube defects.[5]
# Model organisms
Model organisms have been used in the study of MTHFD1L function. A conditional knockout mouse line, called Mthfd1ltm1a(EUCOMM)Wtsi[10][11] 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.[12][13][14]
Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion.[8][15] Twenty six tests were carried out on mutant mice and two significant abnormalities were observed.[8] The homozygous mutant embryos identified during gestation had exencephaly. None survived until weaning. The remaining tests were carried out on heterozygous mutant adult mice and no further abnormalities were observed.[8] | https://www.wikidoc.org/index.php/MTHFD1L | |
83361d5927564b57ff7a9f7e70f89b1f10757249 | wikidoc | MTHFD2L | MTHFD2L
NAD-dependent methylenetetrahydrofolate dehydrogenase 2-like protein (MTHFD2L), also known as bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2, is an enzyme that in humans is encoded by the MTHFD2L gene on chromosome 4. This enzyme localizes to the inner mitochondrial membrane, where it performs the NADP+-dependent dehydrogenase/cyclohydrolase activity as part of the mitochondrial pathway to convert folate to formate.
It is associated with fluctuations in cytokine secretion in response to viral infections and vaccines.
# Structure
The MTHFD2L gene consists of nine exons and is conserved among mammals. This gene encodes a 340-residue protein that is homologous to the mitochondrial bifunctional dehydrogenase/cyclohydrolase (MTHFD2) and to the N-terminal dehydrogenase/cyclohydrolase domains of cytoplasmic and mitochondrial C1-THF synthases (MTHFD1 and MTHFD1L, respectively). The MTHFD2L protein contains a predicted N-terminal mitochondrial targeting sequence and four amino acids (Lys-93, Arg-206, Gly-211, and Arg-238) necessary for the protein's dehydrogenase/cyclohydrolase activity. Three classes of MTHFD2L RNA transcripts have been detected at equal levels in adult human brain and placenta, though their translation into stable proteins in vivo has not been confirmed.
# Function
MTHFD2L is a member of the tetrahydrofolate dehydrogenase/cyclohydrolase family. This enzyme is expressed in all adult tissues and localizes to the mitochondria, specifically as a peripheral membrane protein in the mitochondrial matrix side of the inner mitochondrial membrane. Within the mitochondria, it participates the conversion of folate to formate as part of the mitochondrial pathway for 1-carbon metabolism. In the final step of this pathway, the NADP+-dependent CH2-THF dehydrogenase/CH+-THF cyclohydrolase activity of bifunctional MTHFD2L complements the 10-CHO-THF synthetase activity of monofunctional MTHFD1L. The formate produced via the mitochondrial pathway can contribute to purine and thymidine synthesis and homocysteine remethylation into methionine, as well as be converted into 1-carbon units to fuel the cytoplasmic pathway of folate metabolism.
# Clinical significance
In a GWAS study concerning variations in cytokine responses observed in smallpox vaccine recipients, a number of SNPs associated with variations in IL-1β secretion were identified in or within the vicinity of the MTHFD2L gene. Identification of the genetic elements controlling cytokine secretion in response to viral infection or vaccination can improve next-generation vaccines to provide robust immune protection while avoiding adverse effects. | MTHFD2L
NAD-dependent methylenetetrahydrofolate dehydrogenase 2-like protein (MTHFD2L), also known as bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase 2, is an enzyme that in humans is encoded by the MTHFD2L gene on chromosome 4.[1][2] This enzyme localizes to the inner mitochondrial membrane, where it performs the NADP+-dependent dehydrogenase/cyclohydrolase activity as part of the mitochondrial pathway to convert folate to formate.[3]
It is associated with fluctuations in cytokine secretion in response to viral infections and vaccines.[4][4]
# Structure
The MTHFD2L gene consists of nine exons and is conserved among mammals. This gene encodes a 340-residue protein that is homologous to the mitochondrial bifunctional dehydrogenase/cyclohydrolase (MTHFD2) and to the N-terminal dehydrogenase/cyclohydrolase domains of cytoplasmic and mitochondrial C1-THF synthases (MTHFD1 and MTHFD1L, respectively). The MTHFD2L protein contains a predicted N-terminal mitochondrial targeting sequence and four amino acids (Lys-93, Arg-206, Gly-211, and Arg-238) necessary for the protein's dehydrogenase/cyclohydrolase activity. Three classes of MTHFD2L RNA transcripts have been detected at equal levels in adult human brain and placenta, though their translation into stable proteins in vivo has not been confirmed.[3]
# Function
MTHFD2L is a member of the tetrahydrofolate dehydrogenase/cyclohydrolase family.[2] This enzyme is expressed in all adult tissues and localizes to the mitochondria, specifically as a peripheral membrane protein in the mitochondrial matrix side of the inner mitochondrial membrane. Within the mitochondria, it participates the conversion of folate to formate as part of the mitochondrial pathway for 1-carbon metabolism.[3][4] In the final step of this pathway, the NADP+-dependent CH2-THF dehydrogenase/CH+-THF cyclohydrolase activity of bifunctional MTHFD2L complements the 10-CHO-THF synthetase activity of monofunctional MTHFD1L.[3][5] The formate produced via the mitochondrial pathway can contribute to purine and thymidine synthesis and homocysteine remethylation into methionine, as well as be converted into 1-carbon units to fuel the cytoplasmic pathway of folate metabolism.[5]
# Clinical significance
In a GWAS study concerning variations in cytokine responses observed in smallpox vaccine recipients, a number of SNPs associated with variations in IL-1β secretion were identified in or within the vicinity of the MTHFD2L gene. Identification of the genetic elements controlling cytokine secretion in response to viral infection or vaccination can improve next-generation vaccines to provide robust immune protection while avoiding adverse effects.[4] | https://www.wikidoc.org/index.php/MTHFD2L | |
d079b71b5e71effba38e04ffaaaea723d10d6685 | wikidoc | MakeBot | MakeBot
# Overview
MakeBot is an extension which allows bureaucrats to grant and revoke bot status from user accounts. It was written by Rob Church for use on Wikimedia wikis, and was taken live on 22nd April 2006.
# Use
# Restrictions
Bot flags can not be placed on accounts that have sysop or bureaucrat flags already set.
# Logs
A log of all bot status changes is maintained at Special:Log/makebot.
# Licencing and downloads
The extension is available under the GNU General Public Licence 2.0 or later, and can be from SVN downloaded from Subversion, or accessed via the web-based viewer.
The software is provided as-is. Updates will be made according to the needs of Wikimedia wikis; or where critical vulnerabilities are discovered. | MakeBot
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
MakeBot is an extension which allows bureaucrats to grant and revoke bot status from user accounts. It was written by Rob Church for use on Wikimedia wikis, and was taken live on 22nd April 2006.
# Use
# Restrictions
Bot flags can not be placed on accounts that have sysop or bureaucrat flags already set.
# Logs
A log of all bot status changes is maintained at Special:Log/makebot.
# Licencing and downloads
The extension is available under the GNU General Public Licence 2.0 or later, and can be from SVN downloaded from Subversion, or accessed via the web-based viewer.
The software is provided as-is. Updates will be made according to the needs of Wikimedia wikis; or where critical vulnerabilities are discovered.
Template:WikiDoc Sources | https://www.wikidoc.org/index.php/MakeBot | |
739f52405974163853c2afa80ce3695ee708cc40 | wikidoc | Malleus | Malleus
# Overview
The malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum. The word is Latin for hammer.
It transmits the sound vibrations from the eardrum to the incus.
The malleus is unique to mammals, and evolved from a lower jaw bone in basal amniotes called the articular, which still forms part of the jaw joint in reptiles.
# Additional images
- Head and neck of a human embryo eighteen weeks old, with Meckel’s cartilage and hyoid bar exposed.
- External and middle ear, opened from the front. Right side.
- Chain of ossicles and their ligaments, seen from the front in a vertical, transverse section of the tympanum. | Malleus
Template:Infobox Bone
# Overview
The malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum. The word is Latin for hammer.
It transmits the sound vibrations from the eardrum to the incus.
The malleus is unique to mammals, and evolved from a lower jaw bone in basal amniotes called the articular, which still forms part of the jaw joint in reptiles.
# Additional images
- Head and neck of a human embryo eighteen weeks old, with Meckel’s cartilage and hyoid bar exposed.
- External and middle ear, opened from the front. Right side.
- Chain of ossicles and their ligaments, seen from the front in a vertical, transverse section of the tympanum. | https://www.wikidoc.org/index.php/Malleus | |
753cbcf2cafbf59b5d1e59f31159d82318743ebd | wikidoc | Mannose | Mannose
Mannose is a sugar monomer of the hexose series of carbohydrates.
# Metabolism
Mannose enters the carbohydrate metabolism stream in two steps:
- First it undergoes phosphorylation to mannose-6-phosphate by hexokinase.
- Then, it is converted to fructose-6-phosphate by mannose phosphate isomerase.
# Formation
Mannose can be formed by the oxidation of mannitol.
It can also be formed from D-glucose in the Lobry-de Bruyn-van Ekenstein transformation
# Etymology
The root of both "mannose" and "manitol" is manna, which the Bible records as the food supplied to the Israelites during their journey through the Sinai Peninsula. Manna is a sweet secretion of several trees and shrubs, such as Fraxinus ornus.
# Cranberry juice
D-Mannose, which appears in some fruits including cranberry, has been shown to prevent the adhesion of bacteria to tissues of the urinary tract and bladder.
# Configuration
The fact that D-mannose has the same configuration at its penultimate carbon as D-glyceraldehyde is unsurprising as that is what defines the dextro classification. However, mannose differs from D-glucose by inversion of the C2 chiral centre. This apparently simple change leads to the drastically different chemistry of the two hexoses, as it does the remaining six hexoses.
# Mnemonic
The hexoses can be remembered conveniently by the following phrase: | Mannose
Template:Chembox new
Mannose is a sugar monomer of the hexose series of carbohydrates.
# Metabolism
Mannose enters the carbohydrate metabolism stream in two steps:
- First it undergoes phosphorylation to mannose-6-phosphate by hexokinase.
- Then, it is converted to fructose-6-phosphate by mannose phosphate isomerase.
# Formation
Mannose can be formed by the oxidation of mannitol.
It can also be formed from D-glucose in the Lobry-de Bruyn-van Ekenstein transformation
# Etymology
The root of both "mannose" and "manitol" is manna, which the Bible records as the food supplied to the Israelites during their journey through the Sinai Peninsula. Manna is a sweet secretion of several trees and shrubs, such as Fraxinus ornus.
# Cranberry juice
D-Mannose, which appears in some fruits including cranberry, has been shown to prevent the adhesion of bacteria to tissues of the urinary tract and bladder.[citation needed]
# Configuration
The fact that D-mannose has the same configuration at its penultimate carbon as D-glyceraldehyde is unsurprising as that is what defines the dextro classification. However, mannose differs from D-glucose by inversion of the C2 chiral centre. This apparently simple change leads to the drastically different chemistry of the two hexoses, as it does the remaining six hexoses.
# Mnemonic
The hexoses can be remembered conveniently by the following phrase: | https://www.wikidoc.org/index.php/Mannose | |
50b03f11cbff1d950b290f138702a80d2801d1a2 | wikidoc | Manroot | Manroot
The Manroots or Wild cucumbers (Marah spp.) are flowering plants in the gourd family Cucurbitaceae native to western North America. They are also commonly called Old man in the ground.
# Characteristics
The manroots are perennial plants, growing from a large tuberous root. Most have stout, scabrous or hairy stems, with coiling tendrils that enable them to climb up other plants; they can also grow rapidly across level ground. Their leaves tend to have multiple lobes, up to 7 in some species. The fruits are striking and easily recognised. They are large, and spherical, oval or cylindrical. At a minimum they are 3 cm in diameter, but can be up to 20 cm long, and in many species they are covered in long spines. Both leaf and fruit shape vary widely between individual plants and leaves can be particularly variable even on the same vine.
The anthropomorphic common names "manroot" and "old man" derive from the swollen lobes and arm-like extensions of the unearthed tuber. On old plants, the tuber can be several meters long and weigh in excess of 100 kg.
The name "Marah" comes from a Hebrew word meaning "bitter" (cf. Ruth 1:20 ), and was given because all parts of these plants tend to have a bitter taste.
# Distribution
Except for the isolated range of Marah gilensis in west-central Arizona, all other manroot species inhabit overlapping ranges distributed from Southern Canada to Northern Mexico. Although Coastal Manroot Marah oreganus extends inland into Idaho, all other manroot species, excluding M. gilensis, are confined to the states and province that immediately border the Pacific Ocean.
# Taxonomy
Marah species hybridize freely where ranges overlap and this, in addition to intra-species leaf and fruit variability, makes definite identification of specimens a particular challenge.
Some authors include the man-roots in genus Echinocystis. Considered as a separate genus, however, it includes six or seven species, some of them with well-defined varieties within them.
# Medicinal uses
Marah oreganus was used by the Native Americans for various problems. The Chinook made a poultice from the gourd. The Squaxin mashed the upper stalk in water to dip aching hands. The Chehalis burned the root and mixed the resulting powder with bear grease to apply to scrofula sores. The Coast Salish made a decoction to treat venereal disease, kidney trouble and scrofula sores.
Seeds of Marah fabaceus have been reported as being hallucinogenic. The tubers of M. fabaceus and M. macrocarpus contain saponins which can act as a natural soap but are toxic if ingested.
Like many medicinal plants, at least some Marah species are toxic and deaths have been reported from ingesting them.
# Species in genus Marah
- California Manroot, Marah fabaceus
Marah fabaceus var. agrestis
Marah fabaceus var. fabaceus
- Marah fabaceus var. agrestis
- Marah fabaceus var. fabaceus
- Gila Manroot, Marah gilensis
- Sierra Manroot, Marah horridus
- Cucamonga Manroot, Marah macrocarpus
Marah macrocarpus var. macrocarpus
Marah macrocarpus var. major
Marah macrocarpus var. micranthus
- Marah macrocarpus var. macrocarpus
- Marah macrocarpus var. major
- Marah macrocarpus var. micranthus
- Coastal Manroot Marah oreganus
- Taw Manroot Marah watsonii | Manroot
The Manroots or Wild cucumbers (Marah spp.) are flowering plants in the gourd family Cucurbitaceae native to western North America. They are also commonly called Old man in the ground.
# Characteristics
The manroots are perennial plants, growing from a large tuberous root. Most have stout, scabrous or hairy stems, with coiling tendrils that enable them to climb up other plants; they can also grow rapidly across level ground. Their leaves tend to have multiple lobes, up to 7 in some species. The fruits are striking and easily recognised. They are large, and spherical, oval or cylindrical. At a minimum they are 3 cm in diameter, but can be up to 20 cm long, and in many species they are covered in long spines. Both leaf and fruit shape vary widely between individual plants and leaves can be particularly variable even on the same vine.
The anthropomorphic common names "manroot" and "old man" derive from the swollen lobes and arm-like extensions of the unearthed tuber. On old plants, the tuber can be several meters long and weigh in excess of 100 kg.
The name "Marah" comes from a Hebrew word meaning "bitter" (cf. Ruth 1:20 [1]), and was given because all parts of these plants tend to have a bitter taste.
# Distribution
Except for the isolated range of Marah gilensis in west-central Arizona, all other manroot species inhabit overlapping ranges distributed from Southern Canada to Northern Mexico. Although Coastal Manroot Marah oreganus extends inland into Idaho, all other manroot species, excluding M. gilensis, are confined to the states and province that immediately border the Pacific Ocean.
# Taxonomy
Marah species hybridize freely where ranges overlap and this, in addition to intra-species leaf and fruit variability, makes definite identification of specimens a particular challenge.
Some authors include the man-roots in genus Echinocystis. Considered as a separate genus, however, it includes six or seven species, some of them with well-defined varieties within them.
# Medicinal uses
Marah oreganus was used by the Native Americans for various problems. The Chinook made a poultice from the gourd. The Squaxin mashed the upper stalk in water to dip aching hands. The Chehalis burned the root and mixed the resulting powder with bear grease to apply to scrofula sores. The Coast Salish made a decoction to treat venereal disease, kidney trouble and scrofula sores.
Seeds of Marah fabaceus have been reported as being hallucinogenic. The tubers of M. fabaceus and M. macrocarpus contain saponins which can act as a natural soap but are toxic if ingested.
Like many medicinal plants, at least some Marah species are toxic and deaths have been reported from ingesting them.
# Species in genus Marah
- California Manroot, Marah fabaceus
Marah fabaceus var. agrestis
Marah fabaceus var. fabaceus
- Marah fabaceus var. agrestis
- Marah fabaceus var. fabaceus
- Gila Manroot, Marah gilensis
- Sierra Manroot, Marah horridus
- Cucamonga Manroot, Marah macrocarpus
Marah macrocarpus var. macrocarpus
Marah macrocarpus var. major
Marah macrocarpus var. micranthus
- Marah macrocarpus var. macrocarpus
- Marah macrocarpus var. major
- Marah macrocarpus var. micranthus
- Coastal Manroot Marah oreganus
- Taw Manroot Marah watsonii
# External links
- Jepson manual treatment of genus Marah
- Website About 5 California-native Marah Species | https://www.wikidoc.org/index.php/Manroot | |
b8103b58176b92b4bc8401859523de7ea0bc0d50 | wikidoc | Methane | Methane
# Overview
Methane is a chemical compound with the molecular formula CH4. It is the simplest alkane, and the principal component of natural gas. Methane's bond angles are 109.5 degrees. Burning one molecule of methane in the presence of oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O:
Methane's relative abundance and clean burning process makes it a very attractive fuel. However, because it is a gas (at normal temperature and pressure - see, STP) and not a liquid or solid, methane is difficult to transport from the areas that produce it to the areas that consume it. Converting methane to derivatives that are more easily transported, such as methanol, is an active area of research. Certain microorganisms can effect this selective oxidation using enzymes called methane monooxygenases.
Methane is a relatively potent greenhouse gas with a high global warming potential (i.e., warming effect compared to carbon dioxide). When averaged over 100 years each kg of CH4 warms the Earth
times as much as the same mass of CO2. The total warming effect of CH4 is smaller than that of CO2, since there is approximately 220 times as much CO2 in the Earth's atmosphere as methane. However, methane in the atmosphere is eventually oxidised, producing carbon dioxide and water. Methane in the atmosphere has a half life of seven years, meaning that every seven years, half of the methane present is converted to carbon dioxide and water.
The Earth's crust contains huge amounts of methane. Large amounts of methane are produced anaerobically by methanogenesis. Other sources include mud volcanoes which are connected with deep geological faults.
# Properties
Methane is the major component of a natural gas, about 97% by volume. At room temperature and standard pressure, methane is a colorless, odorless gas; the smell characteristic of natural gas is an artificial safety measure caused by the addition of an odorant, often methanethiol or ethanethiol. Methane has a boiling point of −161°C at a pressure of one atmosphere. As a gas it is flammable only over a narrow range of concentrations (5–15%) in air. Liquid methane does not burn unless subjected to high pressure (normally 4–5 atmospheres.)
## Potential health effects
Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogens, and some halogen-containing compounds. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia may result if the oxygen concentration is reduced to below 19.5% by displacement. The concentrations at which flammable or explosive mixtures form are much lower than the concentration at which asphyxiation risk is significant. When structures are built on or near landfills, methane off-gas can penetrate the buildings' interiors and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements to actively capture such fugitive off-gas and vent it away from the building. An example of this type of system is in the Dakin Building, Brisbane, California.
## Reactions of methane
Main reactions with methane are: combustion, steam reforming to syngas, and halogenation. In general, methane reactions are hard to control. Partial oxidation to methanol, for example, is difficult to achieve; the reaction typically progresses all the way to carbon dioxide and water.
### Combustion
In the combustion of methane, several steps are involved:
Methane is believed to form a formaldehyde (HCHO or H2CO). The formaldehyde gives a formyl radical (HCO), which then forms carbon monoxide (CO). The process is called oxidative pyrolysis:
Following oxidative pyrolysis, the H2 oxidizes, forming H2O, replenishing the active species, and releasing heat. This occurs very quickly, usually in significantly less than a millisecond.
Finally, the CO oxidizes, forming CO2 and releasing more heat. This process is generally slower than the other chemical steps, and typically requires a few to several milliseconds to occur.
### Hydrogen activation
The strength of the carbon-hydrogen covalent bond in methane is among the strongest in all hydrocarbons, and thus its use as a chemical feedstock is limited. Despite the high activation barrier for breaking the C–H bond, CH4 is still the principal starting material for manufacture of hydrogen in steam reforming. The search for catalysts which can facilitate C–H bond activation in methane and other low alkanes is an area of research with considerable industrial significance.
### Reactions with halogens
Methane reacts with all halogens given appropriate conditions, as follows:
where X is a halogen: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This mechanism for this process is called free radical halogenation.
# Uses
## Fuel
Methane is important for electrical generation by burning it as a fuel in a gas turbine or steam boiler. Compared to other hydrocarbon fuels, burning methane produces less carbon dioxide for each unit of heat released. Also, methane's heat of combustion is about 802 kJ/mol, which is lower than any other hydrocarbon, but if a ratio is made with the molecular mass (16.0 g/mol) divided by the heat of combustion (802 kJ/mol) it is found that methane, being the simplest hydrocarbon, actually produces the most heat per unit mass than other complex hydrocarbons. In many cities, methane is piped into homes for domestic heating and cooking purposes. In this context it is usually known as natural gas, and is considered to have an energy content of 1,000 BTU/standard cubic foot.
Methane in the form of compressed natural gas is used as a fuel for vehicles, and is claimed to be more environmentally friendly than alternatives such as gasoline/petrol and diesel. Research is being conducted by NASA on methane's potential as a rocket fuel. One advantage of methane is that it is abundant in many parts of the solar system and it could potentially be harvested in situ, providing fuel for a return journey.
## Industrial uses
Methane is used in industrial chemical processes and may be transported as a refrigerated liquid (liquefied natural gas, or LNG). While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air. Gas pipelines distribute large amounts of natural gas, of which methane is the principal component.
In the chemical industry, methane is the feedstock of choice for the production of hydrogen, methanol, acetic acid, and acetic anhydride. When used to produce any of these chemicals, methane is first converted to synthesis gas, a mixture of carbon monoxide and hydrogen, by steam reforming. In this process, methane and steam react on a nickel catalyst at high temperatures (700–1100 °C).
The ratio of carbon monoxide to hydrogen in synthesis gas can then be adjusted via the water gas shift reaction to the appropriate value for the intended purpose.
Less significant methane-derived chemicals include acetylene, prepared by passing methane through an electric arc, and the chloromethanes (chloromethane, dichloromethane, chloroform, and carbon tetrachloride), produced by reacting methane with chlorine gas. However, the use of these chemicals is declining, acetylene as it is replaced by less costly substitutes, and the chloromethanes due to health and environmental concerns.
# Sources of methane
## Natural gas fields
The major source of methane is extraction from geological deposits known as natural gas fields. It is associated with other hydrocarbon fuels and sometimes accompanied by helium and nitrogen. The gas at shallow levels (low pressure) is formed by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface. In general, sediments buried deeper and at higher temperatures than those which give oil generate natural gas. Methane is also produced in considerable quantities from the decaying organic wastes of solid waste landfills.
## Alternative sources
Apart from gas fields an alternative method of obtaining methane is via biogas generated by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste (including landfills), or any other biodegradable feedstock, under anaerobic conditions. Methane hydrates/clathrates (icelike combinations of methane and water on the sea floor, found in vast quantities) are a potential future source of methane. Some say that significant quantities are also produced by cattle belching. This however, remains to be proven and most scientists refute this as a fact. The livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane". However animals "that put their energies into making gas are less efficient at producing milk and meat". Early research has found a number of medical treatments and dietary adjustments that help limit the production of methane in ruminants.
Industrially, methane can be created from common atmospheric gases and hydrogen (produced, perhaps, by electrolysis) through chemical reactions such as the Sabatier process, Fischer-Tropsch process. Coal bed methane extraction is a method for extracting methane from a coal deposit.
A recent scientific experiment has also yielded results pointing to the fact that all plants produce methane, and as the climate warms they produce more . In fact 600 million metric tons of methane a year are produced, 225 of those produced by plants.
# Methane in Earth's atmosphere
Methane in the Earth's atmosphere is an important greenhouse gas with a global warming potential of 25 over a 100 year period. This means that a 1 tonne methane emission will have 25 times the impact on temperature of a 1 tonne carbon dioxide emission during the following 100 years. Methane has a large effect for a brief period (about 10 years), whereas carbon dioxide has a small effect for a long period (over 100 years). Because of this difference in effect and time period, the global warming potential of methane over a 20 year time period is 72. The methane concentration has increased by about 150% since 1750 and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases.
The average concentration of methane at the Earth's surface in 1998 was 1,745 ppb. Its concentration is higher in the northern hemisphere as most sources (both natural and human) are larger. The concentrations vary seasonally with a minimum in the late summer.
Methane is created near the surface, and it is carried into the stratosphere by rising air in the tropics. Uncontrolled build-up of methane in Earth's atmosphere is naturally checked—although human influence can upset this natural regulation—by methane's reaction with a molecule known as the hydroxyl radical, a hydrogen-oxygen molecule formed when single oxygen atoms react with water vapor.
Early in the Earth's history—about 3.5 billion years ago—there was 1,000 times as much methane in the atmosphere as there is now. The earliest methane was released into the atmosphere by volcanic activity. During this time, Earth's earliest life appeared. These first, ancient bacteria added to the methane concentration by converting hydrogen and carbon dioxide into methane and water. Oxygen did not become a major part of the atmosphere until photosynthetic organisms evolved later in Earth's history. With no oxygen, methane stayed in the atmosphere longer and at higher concentrations than it does today.
## Emissions of methane
Houweling et al. (1999) give the following values for methane emissions (Tg/a=teragrams per year):
Slightly over half of the total emission is due to human activity.
Living plants (e.g. forests) have recently been identified as a potentially important source of methane. A 2006 paper calculated emissions of 62–236 Tg a-1, and "this newly identified source may have important implications". However the authors stress "our findings are preliminary with regard to the methane emission strength". These findings have been called into question in a 2007 paper which found "there is no evidence for substantial aerobic methane emission by terrestrial plants, maximally 0.3% of the previously published values".
Long term atmospheric measurements of methane by NOAA show that the build up of methane has slowed dramatically over the last decade, after nearly tripling since pre-industrial times . It is thought that this reduction is due to reduced industrial emissions and drought in wetland areas.
## Removal processes
The major removal mechanism of methane from the atmosphere is by reaction with the hydroxyl radical (·OH), which may be produced when a cosmic ray strikes a molecule of water vapor:
This reaction in the troposphere gives a methane lifetime of 9.6 years. Two more minor sinks are soil sinks (160 year lifetime) and stratospheric loss by reaction with ·OH, ·Cl and ·O1D in the stratosphere (120 year lifetime), giving a net lifetime of 8.4 years. Oxidation of methane is the main source of water vapor in the upper stratosphere (beginning at pressure levels around 10 kPa).
## Sudden release from methane clathrates
At high pressures, such as are found on the bottom of the ocean, methane forms a solid clathrate with water, known as methane hydrate. An unknown, but possibly very large quantity of methane is trapped in this form in ocean sediments. The sudden release of large volumes of methane from such sediments into the atmosphere has been suggested as a possible cause for rapid global warming events in the Earth's distant past, such as the Paleocene–Eocene Thermal Maximum of 55 million years ago.
One source estimates the size of the methane hydrate deposits of the oceans at ten trillion tons (10 exagrams). Theories suggest that should global warming cause them to heat up sufficiently, all of this methane could again be suddenly released into the atmosphere. Since methane is twenty-three times stronger (for a given weight, averaged over 100 years) than CO2 as a greenhouse gas; this would immensely magnify the greenhouse effect, heating Earth to unprecedented levels (see Clathrate gun hypothesis).
## Release of methane from bogs
Although less dramatic than release from clathrates, but already happening, is an increase in the release of methane from bogs as permafrost melts. Although records of permafrost are limited, recent years (1999 to 2007) have seen record thawing of permafrost in Alaska and Siberia.
Recent measurements in Siberia show that the methane released is five times greater than previously estimated .
# Extraterrestrial methane
Methane has been detected or is believed to exist in several locations of the solar system. It is believed to have been created by processes, with the possible exception of Mars.
Traces of methane gas are present in the thin atmosphere of the Earth's Moon.
Methane has also been detected in interstellar clouds.
- Methane is believed to be present on Charon, but it is not 100% confirmed. | Methane
# Overview
Methane is a chemical compound with the molecular formula CH4. It is the simplest alkane, and the principal component of natural gas. Methane's bond angles are 109.5 degrees. Burning one molecule of methane in the presence of oxygen releases one molecule of CO2 (carbon dioxide) and two molecules of H2O:
Methane's relative abundance and clean burning process makes it a very attractive fuel. However, because it is a gas (at normal temperature and pressure - see, STP) and not a liquid or solid, methane is difficult to transport from the areas that produce it to the areas that consume it. Converting methane to derivatives that are more easily transported, such as methanol, is an active area of research. Certain microorganisms can effect this selective oxidation using enzymes called methane monooxygenases.
Methane is a relatively potent greenhouse gas with a high global warming potential (i.e., warming effect compared to carbon dioxide).[1] When averaged over 100 years each kg of CH4 warms the Earth
25[2]
times as much as the same mass of CO2. The total warming effect of CH4 is smaller than that of CO2, since there is approximately 220 times as much CO2 in the Earth's atmosphere as methane.[3] However, methane in the atmosphere is eventually oxidised, producing carbon dioxide and water. Methane in the atmosphere has a half life of seven years, meaning that every seven years, half of the methane present is converted to carbon dioxide and water.
The Earth's crust contains huge amounts of methane. Large amounts of methane are produced anaerobically by methanogenesis. Other sources include mud volcanoes which are connected with deep geological faults.
# Properties
Methane is the major component of a natural gas, about 97% by volume. At room temperature and standard pressure, methane is a colorless, odorless gas; the smell characteristic of natural gas is an artificial safety measure caused by the addition of an odorant, often methanethiol or ethanethiol. Methane has a boiling point of −161°C at a pressure of one atmosphere. As a gas it is flammable only over a narrow range of concentrations (5–15%) in air. Liquid methane does not burn unless subjected to high pressure (normally 4–5 atmospheres.)
## Potential health effects
Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogens, and some halogen-containing compounds. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia may result if the oxygen concentration is reduced to below 19.5% by displacement. The concentrations at which flammable or explosive mixtures form are much lower than the concentration at which asphyxiation risk is significant. When structures are built on or near landfills, methane off-gas can penetrate the buildings' interiors and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements to actively capture such fugitive off-gas and vent it away from the building. An example of this type of system is in the Dakin Building, Brisbane, California.
## Reactions of methane
Main reactions with methane are: combustion, steam reforming to syngas, and halogenation. In general, methane reactions are hard to control. Partial oxidation to methanol, for example, is difficult to achieve; the reaction typically progresses all the way to carbon dioxide and water.
### Combustion
In the combustion of methane, several steps are involved:
Methane is believed to form a formaldehyde (HCHO or H2CO). The formaldehyde gives a formyl radical (HCO), which then forms carbon monoxide (CO). The process is called oxidative pyrolysis:
Following oxidative pyrolysis, the H2 oxidizes, forming H2O, replenishing the active species, and releasing heat. This occurs very quickly, usually in significantly less than a millisecond.
Finally, the CO oxidizes, forming CO2 and releasing more heat. This process is generally slower than the other chemical steps, and typically requires a few to several milliseconds to occur.
### Hydrogen activation
The strength of the carbon-hydrogen covalent bond in methane is among the strongest in all hydrocarbons, and thus its use as a chemical feedstock is limited. Despite the high activation barrier for breaking the C–H bond, CH4 is still the principal starting material for manufacture of hydrogen in steam reforming. The search for catalysts which can facilitate C–H bond activation in methane and other low alkanes is an area of research with considerable industrial significance.
### Reactions with halogens
Methane reacts with all halogens given appropriate conditions, as follows:
where X is a halogen: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This mechanism for this process is called free radical halogenation.
# Uses
## Fuel
Methane is important for electrical generation by burning it as a fuel in a gas turbine or steam boiler. Compared to other hydrocarbon fuels, burning methane produces less carbon dioxide for each unit of heat released. Also, methane's heat of combustion is about 802 kJ/mol, which is lower than any other hydrocarbon, but if a ratio is made with the molecular mass (16.0 g/mol) divided by the heat of combustion (802 kJ/mol) it is found that methane, being the simplest hydrocarbon, actually produces the most heat per unit mass than other complex hydrocarbons. In many cities, methane is piped into homes for domestic heating and cooking purposes. In this context it is usually known as natural gas, and is considered to have an energy content of 1,000 BTU/standard cubic foot.
Methane in the form of compressed natural gas is used as a fuel for vehicles, and is claimed to be more environmentally friendly than alternatives such as gasoline/petrol and diesel. Research is being conducted by NASA on methane's potential as a rocket fuel. One advantage of methane is that it is abundant in many parts of the solar system and it could potentially be harvested in situ, providing fuel for a return journey. [2]
## Industrial uses
Methane is used in industrial chemical processes and may be transported as a refrigerated liquid (liquefied natural gas, or LNG). While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air. Gas pipelines distribute large amounts of natural gas, of which methane is the principal component.
In the chemical industry, methane is the feedstock of choice for the production of hydrogen, methanol, acetic acid, and acetic anhydride. When used to produce any of these chemicals, methane is first converted to synthesis gas, a mixture of carbon monoxide and hydrogen, by steam reforming. In this process, methane and steam react on a nickel catalyst at high temperatures (700–1100 °C).
The ratio of carbon monoxide to hydrogen in synthesis gas can then be adjusted via the water gas shift reaction to the appropriate value for the intended purpose.
Less significant methane-derived chemicals include acetylene, prepared by passing methane through an electric arc, and the chloromethanes (chloromethane, dichloromethane, chloroform, and carbon tetrachloride), produced by reacting methane with chlorine gas. However, the use of these chemicals is declining, acetylene as it is replaced by less costly substitutes, and the chloromethanes due to health and environmental concerns.
# Sources of methane
## Natural gas fields
The major source of methane is extraction from geological deposits known as natural gas fields. It is associated with other hydrocarbon fuels and sometimes accompanied by helium and nitrogen. The gas at shallow levels (low pressure) is formed by anaerobic decay of organic matter and reworked methane from deep under the Earth's surface. In general, sediments buried deeper and at higher temperatures than those which give oil generate natural gas. Methane is also produced in considerable quantities from the decaying organic wastes of solid waste landfills.
## Alternative sources
Apart from gas fields an alternative method of obtaining methane is via biogas generated by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste (including landfills), or any other biodegradable feedstock, under anaerobic conditions. Methane hydrates/clathrates (icelike combinations of methane and water on the sea floor, found in vast quantities) are a potential future source of methane. Some say that significant quantities are also produced by cattle belching. This however, remains to be proven and most scientists refute this as a fact. [4][5] The livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane".[6] However animals "that put their energies into making gas are less efficient at producing milk and meat". Early research has found a number of medical treatments and dietary adjustments that help limit the production of methane in ruminants.[7] [8]
Industrially, methane can be created from common atmospheric gases and hydrogen (produced, perhaps, by electrolysis) through chemical reactions such as the Sabatier process, Fischer-Tropsch process. Coal bed methane extraction is a method for extracting methane from a coal deposit.
A recent scientific experiment has also yielded results pointing to the fact that all plants produce methane, and as the climate warms they produce more [9]. In fact 600 million metric tons of methane a year are produced, 225 of those produced by plants.
# Methane in Earth's atmosphere
Methane in the Earth's atmosphere is an important greenhouse gas with a global warming potential of 25 over a 100 year period. This means that a 1 tonne methane emission will have 25 times the impact on temperature of a 1 tonne carbon dioxide emission during the following 100 years. Methane has a large effect for a brief period (about 10 years), whereas carbon dioxide has a small effect for a long period (over 100 years). Because of this difference in effect and time period, the global warming potential of methane over a 20 year time period is 72. The methane concentration has increased by about 150% since 1750 and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases.[10]
The average concentration of methane at the Earth's surface in 1998 was 1,745 ppb.[11] Its concentration is higher in the northern hemisphere as most sources (both natural and human) are larger. The concentrations vary seasonally with a minimum in the late summer.
Methane is created near the surface, and it is carried into the stratosphere by rising air in the tropics. Uncontrolled build-up of methane in Earth's atmosphere is naturally checked—although human influence can upset this natural regulation—by methane's reaction with a molecule known as the hydroxyl radical, a hydrogen-oxygen molecule formed when single oxygen atoms react with water vapor.
Early in the Earth's history—about 3.5 billion years ago—there was 1,000 times as much methane in the atmosphere as there is now. The earliest methane was released into the atmosphere by volcanic activity. During this time, Earth's earliest life appeared. These first, ancient bacteria added to the methane concentration by converting hydrogen and carbon dioxide into methane and water. Oxygen did not become a major part of the atmosphere until photosynthetic organisms evolved later in Earth's history. With no oxygen, methane stayed in the atmosphere longer and at higher concentrations than it does today.
## Emissions of methane
Houweling et al. (1999) give the following values for methane emissions (Tg/a=teragrams per year):[11]
Slightly over half of the total emission is due to human activity.[10]
Living plants (e.g. forests) have recently been identified as a potentially important source of methane. A 2006 paper calculated emissions of 62–236 Tg a-1, and "this newly identified source may have important implications".[12][13] However the authors stress "our findings are preliminary with regard to the methane emission strength".[14] These findings have been called into question in a 2007 paper which found "there is no evidence for substantial aerobic methane emission by terrestrial plants, maximally 0.3% of the previously published values".[15]
Long term atmospheric measurements of methane by NOAA show that the build up of methane has slowed dramatically over the last decade, after nearly tripling since pre-industrial times [16]. It is thought that this reduction is due to reduced industrial emissions and drought in wetland areas.
## Removal processes
The major removal mechanism of methane from the atmosphere is by reaction with the hydroxyl radical (·OH), which may be produced when a cosmic ray strikes a molecule of water vapor:
This reaction in the troposphere gives a methane lifetime of 9.6 years. Two more minor sinks are soil sinks (160 year lifetime) and stratospheric loss by reaction with ·OH, ·Cl and ·O1D in the stratosphere (120 year lifetime), giving a net lifetime of 8.4 years.[11] Oxidation of methane is the main source of water vapor in the upper stratosphere (beginning at pressure levels around 10 kPa).
## Sudden release from methane clathrates
At high pressures, such as are found on the bottom of the ocean, methane forms a solid clathrate with water, known as methane hydrate. An unknown, but possibly very large quantity of methane is trapped in this form in ocean sediments. The sudden release of large volumes of methane from such sediments into the atmosphere has been suggested as a possible cause for rapid global warming events in the Earth's distant past, such as the Paleocene–Eocene Thermal Maximum of 55 million years ago.
One source estimates the size of the methane hydrate deposits of the oceans at ten trillion tons (10 exagrams). Theories suggest that should global warming cause them to heat up sufficiently, all of this methane could again be suddenly released into the atmosphere. Since methane is twenty-three times stronger (for a given weight, averaged over 100 years) than CO2 as a greenhouse gas; this would immensely magnify the greenhouse effect, heating Earth to unprecedented levels (see Clathrate gun hypothesis).
## Release of methane from bogs
Although less dramatic than release from clathrates, but already happening, is an increase in the release of methane from bogs as permafrost melts. Although records of permafrost are limited, recent years (1999 to 2007) have seen record thawing of permafrost in Alaska and Siberia.
Recent measurements in Siberia show that the methane released is five times greater than previously estimated [17].
# Extraterrestrial methane
Methane has been detected or is believed to exist in several locations of the solar system. It is believed to have been created by processes, with the possible exception of Mars.
Traces of methane gas are present in the thin atmosphere of the Earth's Moon.[18]
Methane has also been detected in interstellar clouds.[19]
- Methane is believed to be present on Charon, but it is not 100% confirmed.[20] | https://www.wikidoc.org/index.php/Marsh_gas | |
b6ad2f01a8c568e5508f5491ccb9da8ebad9d2da | wikidoc | Maxilla | Maxilla
# Overview
The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible, which is also a fusion of two halves at the mental symphysis.
# Function
The alveolar process of the maxilla holds the upper teeth, and is referred to as the maxillary arch. The maxilla attaches laterally to the zygomatic bones (cheek bones).
The maxilla assists in forming the boundaries of three cavities:
- the roof of the mouth
- the floor and lateral wall of the nasal antrum
- the floor of the orbit
The maxilla also enters into the formation of two fossae: the infratemporal and pterygopalatine, and two fissures, the inferior orbital and pterygomaxillary.
# Components
Each half of the fused maxilla consists of:
- The body of the maxilla
- Four processes
The zygomatic process
The frontal process
The alveolar process
The palatine process
- The zygomatic process
- The frontal process
- The alveolar process
- The palatine process
- Infraorbital foramen
# Articulations
The maxilla articulates with nine bones:
- two of the cranium: the frontal and ethmoid
- seven of the face: the nasal, zygomatic, lacrimal, inferior nasal concha, palatine, vomer, and the adjacent fused maxillary bone.
Sometimes it articulates with the orbital surface, and sometimes with the lateral pterygoid plate of the sphenoid.
# Additional images
- The seven bones which articulate to form the orbit.
- Facial bones.
- Left maxilla. Outer surface.
- Left maxilla. Nasal surface.
- Left maxillary sinus opened from the exterior.
- The bony palate and alveolar arch.
- Sphenoid bone visible center right.
- Articulation of left palatine bone with maxilla.
- Side view of the teeth and jaws. | Maxilla
Template:Infobox Bone
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
# Overview
The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible, which is also a fusion of two halves at the mental symphysis.
# Function
The alveolar process of the maxilla holds the upper teeth, and is referred to as the maxillary arch. The maxilla attaches laterally to the zygomatic bones (cheek bones).
The maxilla assists in forming the boundaries of three cavities:
- the roof of the mouth
- the floor and lateral wall of the nasal antrum
- the floor of the orbit
The maxilla also enters into the formation of two fossae: the infratemporal and pterygopalatine, and two fissures, the inferior orbital and pterygomaxillary.
# Components
Each half of the fused maxilla consists of:
- The body of the maxilla
- Four processes
The zygomatic process
The frontal process
The alveolar process
The palatine process
- The zygomatic process
- The frontal process
- The alveolar process
- The palatine process
- Infraorbital foramen
# Articulations
The maxilla articulates with nine bones:
- two of the cranium: the frontal and ethmoid
- seven of the face: the nasal, zygomatic, lacrimal, inferior nasal concha, palatine, vomer, and the adjacent fused maxillary bone.
Sometimes it articulates with the orbital surface, and sometimes with the lateral pterygoid plate of the sphenoid.
# Additional images
- The seven bones which articulate to form the orbit.
- Facial bones.
- Left maxilla. Outer surface.
- Left maxilla. Nasal surface.
- Left maxillary sinus opened from the exterior.
- The bony palate and alveolar arch.
- Sphenoid bone visible center right.
- Articulation of left palatine bone with maxilla.
- Side view of the teeth and jaws. | https://www.wikidoc.org/index.php/Maxilla |
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