question
stringlengths 13
215
| ground_truth
stringlengths 2
3.15k
| context
stringlengths 0
157k
|
|---|---|---|
Which technique led to the elucidation of the role of HOXD10 in regulating lymphatic endothelial responses to VEGF-C? | DeepCAGE transcriptomics identify HOXD10 as a transcription factor regulating lymphatic endothelial responses to VEGF-C. | Author information:
(1)Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical
Sciences, ETH Zurich, Zurich 8093, Switzerland.
(2)Centre for Molecular Medicine and Therapeutics, Child and Family Research
Institute, Department of Medical Genetics, University British Columbia,
Vancouver, British Columbia, Canada V5Z 4H4.
(3)Division of Plastic and Reconstructive Surgery, Department of Surgery, Norris
Comprehensive Cancer Center, University of Southern California, Los Angeles, CA
90033, USA.
(4)RIKEN Center for Life Science Technologies, Division of Genomic Technologies,
Yokohama, Kanagawa 230-0045, Japan.
(5)RIKEN Center for Life Science Technologies, Division of Genomic Technologies,
Yokohama, Kanagawa 230-0045, Japan Telethon Kids Institute, The University of
Western Australia, Subiaco, Western Australia 6008, Australia.
(6)RIKEN Preventive Medicine and Diagnosis Innovation Program, Wako, Saitama
351-0198, Japan.
(7)RIKEN Center for Life Science Technologies, Division of Genomic Technologies,
Yokohama, Kanagawa 230-0045, Japan Cancer and Cell Biology Division, Harry
Perkins Institute of Medical Research, QEII Medical Centre and Centre for
Medical Research, the University of Western Australia, Nedlands, Western
Australia 6009, Australia.
(8)Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical
Sciences, ETH Zurich, Zurich 8093, Switzerland [email protected]. |
Is Obeticholic Acid used for treatment of Primary Biliary Cholangitis? | Yes, obeticholic acid is a farnesoid-X receptor agonist that is approved for the treatment of primary biliary cholangitis in combination with ursodeoxycholic acid in adults with an inadequate response to ursodeoxycholic acid, or as monotherapy in adults unable to tolerate ursodeoxycholic acid. | Obeticholic acid (Ocaliva(TM)) is a farnesoid-X receptor (FXR) agonist that is
being developed by Intercept Pharmaceuticals for the treatment of various liver
diseases, and has recently been granted accelerated approval in the USA for the
treatment of primary biliary cholangitis in combination with ursodeoxycholic
acid in adults with an inadequate response to ursodeoxycholic acid, or as
monotherapy in adults unable to tolerate ursodeoxycholic acid. The drug is in
preregistration for this indication in the EU. This article summarizes the
milestones in the development of obeticholic acid leading to this first approval
for primary biliary cholangitis. INTRODUCTION: Primary biliary cholangitis (PBC) is an autoimmune disease of the
liver characterized by destruction and inflammation of the intrahepatic bile
ducts. The disease affects mainly women. The disease is often discovered through
abnormal alkaline phosphatase (ALP) activity, and is confirmed when
anti-mitochondrial antibodies (AMA) are present. The etiology of PBC is poorly
understood. Cigarette smoking, immune dysregulation, nail polish, urinary tract
infections, and low socioeconomic status have been implicated but none have been
confirmed. Genome wide association studies (GWAS) have disclosed strong
associations between certain human leukocyte antigen (HLA) alleles and PBC. PBC
can progress to cirrhosis and end-stage liver disease. Hepatocellular carcinoma
(HCC) develops in up to 3.5% of PBC patients. Ursodeoxycholic acid (UDCA) is the
only medication approved for the treatment of PBC. The use of UDCA in PBC delays
histological progression and extends the transplant-free survival. 40% of PBC
patients do not respond adequately to UDCA, and these patients are at high risk
for serious complications. Therefore, there is a critical need for more
effective therapies for this problematic disease. Multiple other agents have
either been or are currently being studied as therapeutic options in UDCA
non-responder PBC patients. Six-ethyl chenodeoxycholic acid (6-ECDCA), a potent
farnesoid X receptor (FXR) agonist, has shown anti-cholestatic activity in
rodent models of cholestasis. Obeticholic acid (OCA, 6-ECDCA, or INT-747), a
first-in-class FXR agonist, has been examined in PBC patients with inadequate
response to UDCA, and shown promising results. Particularly, initial clinical
trials have demonstrated that the use of OCA (in addition to UDCA) in PBC
patients with inadequate response to UDCA led to significant reduction of serum
alkaline phosphatase (ALP, an important prognostic marker in PBC). More
recently, the results of a randomized clinical trial of OCA monotherapy in PBC
reported significant reduction of ALP in the treatment group compared to
placebo.
AREAS COVERED: This review covers the preclinical and clinical studies of OCA in
PBC. In addition, other alternative therapies that are currently being examined
in PBC patients will also be discussed in this review. A literature search was
carried out using the PubMed database.
EXPERT OPINION: If approved by the U.S. FDA, OCA will likely be an important
alternative add-on therapy in PBC patients who have inadequate response to UDCA. BACKGROUND: Primary biliary cholangitis (formerly called primary biliary
cirrhosis) can progress to cirrhosis and death despite ursodiol therapy.
Alkaline phosphatase and bilirubin levels correlate with the risk of liver
transplantation or death. Obeticholic acid, a farnesoid X receptor agonist, has
shown potential benefit in patients with this disease.
METHODS: In this 12-month, double-blind, placebo-controlled, phase 3 trial, we
randomly assigned 217 patients who had an inadequate response to ursodiol or who
found the side effects of ursodiol unacceptable to receive obeticholic acid at a
dose of 10 mg (the 10-mg group), obeticholic acid at a dose of 5 mg with
adjustment to 10 mg if applicable (the 5-10-mg group), or placebo. The primary
end point was an alkaline phosphatase level of less than 1.67 times the upper
limit of the normal range, with a reduction of at least 15% from baseline, and a
normal total bilirubin level.
RESULTS: Of 216 patients who underwent randomization and received at least one
dose of obeticholic acid or placebo, 93% received ursodiol as background
therapy. The primary end point occurred in more patients in the 5-10-mg group
(46%) and the 10-mg group (47%) than in the placebo group (10%; P<0.001 for both
comparisons). Patients in the 5-10-mg group and those in the 10-mg group had
greater decreases than those in the placebo group in the alkaline phosphatase
level (least-squares mean, -113 and -130 U per liter, respectively, vs. -14 U
per liter; P<0.001 for both comparisons) and total bilirubin level (-0.02 and
-0.05 mg per deciliter [-0.3 and -0.9 μmol per liter], respectively, vs. 0.12 mg
per deciliter [2.0 μmol per liter]; P<0.001 for both comparisons). Changes in
noninvasive measures of liver fibrosis did not differ significantly between
either treatment group and the placebo group at 12 months. Pruritus was more
common with obeticholic acid than with placebo (56% of patients in the 5-10-mg
group and 68% of those in the 10-mg group vs. 38% in the placebo group). The
rate of serious adverse events was 16% in the 5-10-mg group, 11% in the 10-mg
group, and 4% in the placebo group.
CONCLUSIONS: Obeticholic acid administered with ursodiol or as monotherapy for
12 months in patients with primary biliary cholangitis resulted in decreases
from baseline in alkaline phosphatase and total bilirubin levels that differed
significantly from the changes observed with placebo. There were more serious
adverse events with obeticholic acid. (Funded by Intercept Pharmaceuticals;
POISE ClinicalTrials.gov number, NCT01473524; Current Controlled Trials number,
ISRCTN89514817.). There is significant unmet need in Primary Biliary Cholangitis (PBC) in patients
under-responsive to the only approved therapy Ursodeoxycholic Acid (UDCA) who
are at increased risk of progressing to end-stage liver disease. Obeticholic
Acid (OCA) is a farnesoid X receptor (FXR) agonist which has been evaluated as a
second line therapy in PBC and has recently been licenced by the FDA. Areas
covered: The pharmacology and biology of OCA as an FXR agonist and its clinical
benefits. A systematic review was undertaken of published literature, meeting
abstracts and trial registries using the search terms FXR, FGF-19 (& FGF-15),
Obeticholic Acid and INT-747. Expert commentary: OCA reduces exposure to toxic
hydrophobic bile acids through reduction in bile acid synthesis (by direct and
indirect (via enterocyte-released FGF19) actions on Cyp7A1-mediated bile acid
synthesis) and bile acid excretion by hepatocytes. It significantly improves
liver biochemical parameters strongly associated with risk of disease
progression in UDCA under-responsive patients and the key side-effect of
pruritus can be reduced by optimised dosing. OCA will be the first stratified
therapy introduced in PBC, however confirmatory trial and real life data are
needed to confirm that suggestive biochemical improvements are matched by
improvement in key clinical outcomes. BACKGROUND: Chronic liver disease and cirrhosis are a leading cause of morbidity
and mortality in the United States. Primary biliary cholangitis (PBC),
previously known as primary biliary cirrhosis and which has been designated an
orphan condition, is a chronic autoimmune disease resulting in the destruction
of the small bile ducts in the liver. Without effective treatment, disease
progression frequently leads to liver failure and death. Until May 2016, the
only FDA-approved treatment for PBC was ursodiol (UDCA), an oral hydrophilic
bile acid, which can slow progression of liver damage due to PBC. However, 1 out
of 3 patients taking UDCA has an inadequate biochemical response, leading to
increased risk of disease progression, liver transplantation, and mortality.
Given this unmet clinical need, new therapies are in development for the
treatment of PBC. To provide pharmacists with an overview of the latest research
on the pathophysiology of PBC and potential new treatment options and to
highlight medical and specialty pharmacy approaches to managing access to drugs
to treat orphan diseases such as PBC, a 2-hour satellite symposium was presented
in conjunction with the 2015 Academy of Managed Care Pharmacy (AMCP) Nexus
meeting. Although obeticholic acid was approved by the FDA for the treatment of
PBC in May 2016, this development occurred after the symposium presentation. The
symposium was supported by an independent educational grant from Intercept
Pharmaceuticals and was managed by Analysis Group. Robert Navarro, PharmD,
moderated the CPE-accredited symposium titled "Medical and Specialty Pharmacy
Management Update on Primary Biliary Cirrhosis." Expert panelists included
Christopher L. Bowlus, MD; James T. Kenney, RPh, MBA; and Gary Rice, RPh, MS,
MBA, CSP.
OBJECTIVE: To summarize the educational satellite symposium presentations and
discussions.
SUMMARY: Autoimmune liver diseases, including PBC, are responsible for 15% of
all liver transplants performed and an equal percentage of deaths related to
liver disease. UDCA is the only FDA-approved therapy for treatment of PBC and is
considered the standard of care. Nevertheless, many patients do not respond to
UDCA, creating the need for new therapeutic options to improve clinical outcomes
for PBC patients with inadequate response to treatment. While several agents are
being studied in combination with UDCA, monotherapy with the novel agent
obeticholic acid, a farnesoid X receptor agonist, has also shown promising
results. Health plans are anticipated to assign any newly introduced therapy for
the treatment of PBC to specialty pharmacy given its orphan disease status. This
assignment enables the health plan to receive disease education, which is
particularly important when new drugs are indicated for orphan diseases, and
assistance with designing appropriate prior authorization criteria. The clinical
value of any new therapeutic options that will inform formulary decisions and
prior authorization criteria will be assessed based on evidence of efficacy,
safety, and tolerability, among other factors, such as the potential to reduce
or delay medical resource utilization (e.g., liver transplant). Key
considerations for prior authorization of a new therapy will be determining
which PBC patients are appropriate candidates for the new therapy and developing
criteria for that determination. These are likely to include clinical diagnostic
criteria and degree of response to prior treatment with UDCA. Initially, any new
therapy would likely be positioned as noncovered until appropriate prior
authorization criteria are established.
CONCLUSIONS: PBC is a chronic liver disease with significant morbidity and
mortality, as well as a significant burden on the health care system if the
disease progresses to the point at which a liver transplant is needed. Although
UDCA, the current standard of care, has improved outcomes for many patients,
others have an inadequate response to this treatment. This symposium discussed
these issues and also addressed the overall treatment paradigm for orphan drug
therapies, key implications for patient management, and the role of specialty
pharmacy management and any associated needs both in general and specifically
for new therapeutic options for PBC. In a double-blind, randomized, placebo-controlled study including 217 patients
with primary biliary cholangitis, the authors show that obeticholic acid (a
potent farnesoid X agonist) administered with ursodeoxycholic acid or as
monotherapy significantly decreases serum alkaline phosphatase and bilirubin
when compared to placebo. Pruritus (and serious adverse effects) was observed
more frequently in obeticholic acid-treated patients than in controls, in spite
of a decrease in serum bile acid concentration. These results are encouraging,
but more studies are needed on clinical efficacy and safety before obeticholic
acid can be widely recommended. |
What alternate indication has Vanoxerine been repositioned for? | Vanoxerine's effects were strongly frequency-dependent and we repositioned it for treatment of atrial fibrillation and flutter. Vanoxerine has been in clinical trials for Parkinsonism, depression and cocaine addiction but lacked efficacy. | INTRODUCTION: There remains an unmet need for safe and effective antiarrhythmic
drugs, especially for the treatment of atrial fibrillation. Vanoxerine is a drug
that is free of adverse cardiac events in normal volunteers, yet is a potent
blocker of the hERG (hK(v)11.1) cardiac potassium channel. Consequently,we
hypothesized that vanoxerine might also be a potent blocker of cardiac calcium
(Ca) and sodium (Na) currents, and would not affect transmural dispersion of
repolarization.
METHODS: The whole cell patch clamp technique was used to measure currents from
cloned ion channels overexpressed in stable cell lines and single ventricular
myocytes. We measured intracellular action potentials from canine ventricular
wedges and Purkinje fibers using sharp microelectrode technique.
RESULTS: We found that vanoxerine was a potent hK(v)11.1 blocker, and at
submicromolar concentrations, it blocked Ca and Na currents in a strongly
frequency-dependent manner. In the canine ventricular wedge preparation
vanoxerine did not significantly affect transmural action potential waveforms,
QT interval or transmural dispersion of repolarization.
CONCLUSIONS: Vanoxerine (1) is a potent blocker of cardiac hERG, Na and Ca
channels; (2) block is strongly frequency-dependent especially for Na and Ca
channels; and (3) transmural dispersion of ventricular repolarization is
unaffected. The multichannel block and repolarization uniformity resemble the
effects of amiodarone, the exemplar atrial fibrillation drug. Vanoxerine is a
completely different chemical and has none of amiodarone's toxic effects.
Vanoxerine has characteristics of a potentially effective and safe
antiarrhythmic. BACKGROUND: Vanoxerine produces potent block of cardiac hERG, sodium, and L-type
calcium channels. Block is strongly frequency dependent, is unassociated with
transmural dispersion of repolarization, and occurs at concentrations safe in
humans. Therefore, we proposed that vanoxerine might be antiarrhythmic. In these
studies, we tested the hypothesis that vanoxerine would terminate induced atrial
fibrillation (AF) and atrial flutter (AFL) in dogs with sterile pericarditis
(SP).
METHODS AND RESULTS: In 9 SP dogs, 11 episodes each of sustained (>10 minutes)
AF and AFL were induced. Electrophysiological studies were performed before and
after infusion of vanoxerine, which effectively terminated AF and AFL in 19 of
22 episodes. Simultaneous multisite mapping during 3 AF and 3 AFL episodes
demonstrated that termination of each arrhythmia occurred with termination of
the driver (a reentrant circuit) following an increase in tachycardia CL. Except
for conduction in an area of slow conduction in the driver's reentrant circuit,
vanoxerine did not significantly affect intraatrial or atrioventricular
conduction time, QRS duration, or QT/QTc intervals. Ventricular refractoriness
prolonged minimally during ventricular pacing at 400 and 333 ms (176 +/- 16 ms
to 182 +/- 16 ms; 173 +/- 11 ms to 178 +/- 18 ms, respectively). Vanoxerine
minimally increased (mean 0.7 mA) atrial stimulus threshold for capture.
CONCLUSIONS: Vanoxerine effectively terminated induced, sustained AF and AFL in
the canine SP model, and produced insignificant or minimal changes in
refractoriness, conduction time, or stimulus threshold, consistent with little
proarrhythmic risk. Vanoxerine has been in clinical trials for Parkinsonism, depression and cocaine
addiction but lacked efficacy. Although a potent blocker of hERG, it produced no
serious adverse events. We attributed the unexpected result to offsetting
Multiple Ion Channel Effects (MICE). Vanoxerine's effects were strongly
frequency-dependent and we repositioned it for treatment of atrial fibrillation
and flutter. Vanoxerine terminated AF/AFL in an animal model and a dose-ranging
clinical trial. Reversion to normal rhythm was associated with QT prolongation
yet absent proarrhythmia markers for Torsade de Pointes (TdP). To understand the
QT/TdP discordance, we used quantitative profiling and compared vanoxerine with
dofetilide, a selective hERG-blocking torsadogen used for intractable AF,
verapamil, a non-torsadogenic MICE comparator and bepridil, a torsadogenic MICE
comparator. At clinically relevant concentrations, verapamil blocked hCav1.2 and
hERG, as did vanoxerine and bepridil both of which also blocked hNav1.5. In
acute experiments and simulations, dofetilide produced early after
depolarizations (EADs) and arrhythmias, whereas verapamil, vanoxerine and
bepridil produced no proarrhythmia markers. Of the MICE drugs only bepridil
inhibited hERG trafficking following overnight exposure. The results are
consistent with the emphasis on MICE of the CiPA assay. Additionally we propose
that trafficking inhibition of hERG be added to CiPA. |
What is the applicability of the No Promoter Left Behind method? | No Promoter Left Behind (NPLB) is an efficient, organism-independent method for characterizing promoter architectures directly from experimentally identified genome-wide TSSs, without relying on known promoter elements. | Promoters have diverse regulatory architectures and thus activate genes
differently. For example, some have a TATA-box, many others do not. Even the
ones with it can differ in its position relative to the transcription start site
(TSS). No Promoter Left Behind (NPLB) is an efficient, organism-independent
method for characterizing such diverse architectures directly from
experimentally identified genome-wide TSSs, without relying on known promoter
elements. As a test case, we show its application in identifying novel
architectures in the fly genome.
AVAILABILITY AND IMPLEMENTATION: Web-server at http://nplb.ncl.res.in Standalone
also at https://github.com/computationalBiology/NPLB/ (Mac OSX/Linux).
CONTACT: [email protected]
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics
online. |
Which mutated genes are associated with isolated ectopia lentis? | Isolated ectopia lentis (EL) is caused by mutation in genes:
1) ADAMTSL4 and
2) Fibrillin-1 (FBN1). | Ectopia lentis is a genetically heterogeneous condition that is characterized by
the subluxation of the lens resulting from the disruption of the zonular fibers.
Patients with ectopia lentis commonly present with a marked loss in visual
acuity in addition to a number of possibly accompanying ocular complications
including cataract, myopia, and retinal detachment. We here describe an isolated
form of ectopia lentis in a large inbred family that shows autosomal-recessive
inheritance. We map the ectopia lentis locus in this family to the
pericentromeric region on chromosome 1 (1p13.2-q21.1). The linkage region
contains well more than 60 genes. Mutation screening of four candidate genes
revealed a homozygous nonsense mutation in exon 11 of ADAMTSL4 (p.Y595X;
c.1785T-->G) in all affected individuals that is absent in 380 control
chromosomes. The mutation would result in a truncated protein of half the
original length, if the mRNA escapes nonsense-mediated decay. We conclude that
mutations in ADAMTSL4 are responsible for autosomal-recessive simple ectopia
lentis and that ADAMTS-like4 plays a role in the development and/or integrity of
the zonular fibers. Aortic aneurysm and dissection cause significant morbidity and mortality. There
are several known single gene disorders that predispose to isolated aortic
disease and eventually aneurysm and dissection. FBN1 mutations are associated
with multiple clinical phenotypes, including Marfan syndrome (MFS), MASS
phenotype, and familial ectopia lentis, but rarely with isolated aortic aneurysm
and dissection. In this report, we describe three patients who presented with
primary descending thoracic aortic dissection and who were found to have an FBN1
mutation. None of the patients fulfilled clinical criteria for the diagnosis of
MFS, and all had few or none of the skeletal features typical of the condition.
Two patients had a history of long-term hypertension, and such a history was
suspected in the third patient. These observations suggest that some individuals
with FBN1 mutations have significant aortic disease involvement of other systems
that is typical of FBN1 mutation-related syndromes. Superimposed risk factors,
such as hypertension, may weaken the aortic wall and eventually lead to aortic
dissection. Given that the cost continues to decrease, we suggest that
diagnostic DNA sequencing for FBN1 mutations in patients with thoracic aortic
aneurysms and dissection may be a practical clinical step in evaluating such
patients and at-risk family members. Ectopia lentis (EL) is a zonular disease where alteration of the zonular fibers
leads progressively to lens dislocation. It is most often associated with
systemic diseases such as Marfan syndrome, Weill-Marchesani syndrome or
homocystinuria. Isolated non syndromic ectopia lentis (IEL) is reported in
families with autosomal inheritance, with domit forms being more common than
recessive. LTBP2 truncating mutations have been described as a cause of
autosomal recessive ectopia lentis as a primary or secondary feature in patients
showing ocular (eg, glaucoma) or extraocular manifestations (eg, Marfanoid
habitus). Recently, ADAMTSL4 has been shown to be responsible for isolated
autosomal recessive ectopia lentis in an inbred family. Herein we show a
consanguineous family that carries a novel homozygous splice mutation
IVS4-1G>A/IVS4-1G>A in ADAMTSL4 responsible for isolated autosomal recessive EL,
thus confirming the involvement of this gene in this condition and underlining
the major role of ADAMTS proteases in zonular fibers homeostasis. PURPOSE: The purpose of the study was to look for ADAMTSL4 mutations in a cohort
of German patients with isolated ectopia lentis from nonconsanguineous families.
METHODS: Mutation screening was performed by PCR amplification of the coding
exons of ADAMTSL4 and subsequent sequencing.
RESULTS: An identical homozygous deletion of 20 bp of coding sequence within
exon 6 (NM_019032.4:c.759_778del20) was identified in eight individuals from
seven unrelated families. In a screen of 360 ethnically matched, unaffected
individuals, two heterozygous mutation carriers were found. The mutation was
always accompanied by the identical haplotype, suggestive of a founder mutation.
CONCLUSIONS: The results emphasize the association of ADAMTSL4 null mutations
with isolated ectopia lentis and the presence of a founder mutation in the
European population. Screening of ADAMTSL4 should be considered in all patients
with isolated ectopia lentis, with or without family history. In patients from
nonconsanguineous families, the authors propose a two-step diagnostic approach,
starting with an examination of exon 6 before sequencing the entire coding
region of ADAMTSL4. PURPOSE: To identify the genetic defect in a Chinese family with autosomal
domit inherited ectopia lentis.
METHODS: twenty-one family members, including seven patients underwent general
physical and fully ophthalmic examinations. Genomic DNA was extracted from
leukocytes of venous blood of these individuals in the family. Polymerase chain
reaction (PCR) amplification and direct sequencing of all 65 coding exons of the
fibrillin-1 gene (FBN1) were analyzed.
RESULTS: Mutation screening in FBN1 identified a T>C transition at nucleotide
position c,1759 leading to substitution of Cysteine for Arginine at codon 587
(C587R). This nucleotide substitution was not seen in any unaffected member of
the family.
CONCLUSIONS: We detected a novel mutation in FBN1. Our result expands the
mutation spectrum of FBN1 and help in the study of the molecular pathogenesis of
Marfan syndrome and Marfan-related diseases. PURPOSE: To describe the genotype-phenotype relationship of a cohort of
consecutive patients with isolated ectopia lentis (EL) secondary to ADAMTSL4 and
FBN1 mutations.
METHODS: Patients underwent detailed ocular, cardiovascular, and skeletal
examination. This was correlated with Sanger sequencing of ADAMTSL4 and FBN1
genes.
RESULTS: Seventeen patients were examined, including one with ectopia lentis et
pupillae. Echocardiography and skeletal examination revealed no sign of systemic
disorders associated with EL, in particular Marfan syndrome (MFS). Nine patients
(52.9%) were found to have mutations in ADAMTSL4, including four novel nonsense
mutations. Four patients (25%) were found to have novel FBN1 mutations, not
previously reported as causing classical Marfan syndrome. One additional patient
was found to have an FBN1 mutation previously reported in classical MFS. Four
patients (25%) were found to have no mutations in either gene. Median age of
diagnosis of EL was 35 years in patients with FBN1 mutations and 2 years in
patients with ADAMTSL4 mutations (P < 0.01). Mean axial length was 22.74 mm (95%
confidence interval [CI]: 21.3-24.2) (FBN1) and 27.54 mm (95% CI: 24.2-30.9)
(ADAMTSL4) (P < 0.01). Other ophthalmic features, including corneal thickness
and power, foveal thickness, visual acuity, and direction of lens displacement,
were similar for both groups.
CONCLUSIONS: ADAMTSL4 is the most important known causative gene in isolated EL.
Mutations in ADAMTSL4 appear to cause earlier manifestation of EL and are
associated with increased axial length as compared to FBN1. We suggest that
ADAMTSL4 be screened in all patients with isolated EL and that physicians be
vigilant for the more severe ocular phenotype associated with mutations in this
gene. Craniosynostosis with ectopia lentis has been described five times since 1950
with unknown inheritance and variable phenotype. The patient was diagnosed with
right coronal synostosis at age 10 weeks requiring surgery, and bilateral
ectopia lentis with high myopia at 10 months. No other family member was
affected. There is no known consanguinity within the family. Genetic screening
ruled out FBN1, TGFBR2, and the known craniosynostosis hotspots (FGFR2 exon 8
and exon 10 and FGFR3 exon 6) as the cause. A homozygous deletion in exon 6 of
ADAMTSL4 (c.767_786del 20) that has been shown to cause isolated ectopia lentis
was found. The mutation results in a premature termination codon
(p.Gln256ProfsX38). The proband's mother, father and one sibling are
heterozygous carriers of the mutation. This is the first detailed report of a
possible genetic determit of craniosynostosis with ectopia lentis. Although
this mutation causes isolated ectopia lentis, this may be evidence of
pleiotropic effects of ADAMTSL4 and may represent an overlapping syndrome with a
causative mutation in ADAMTSL4. These findings need to be confirmed in further
cases with craniosynostosis and ectopia lentis. PURPOSE: The purpose of this paper is to describe ophthalmic findings in a
family with isolated ectopia lentis (EL) caused by a specific FBN1 mutation.
METHODS: Detailed family histories and clinical data were recorded for six
isolated EL patients of 11 family members. The ophthalmological and systematic
examinations were performed on patients and unaffected members of the
investigated family. The detailed ocular examinations included visual acuity,
anterior chamber depth, pupil size, lens location, optometry, central corneal
thickness, keratometry, slitlamp examination, fundus examination, axial length,
ocular B-ultrasound, gonioscope checking, ultrasound biomicroscopy (UBM) and
intraocular pressure (IOP; Goldmann applanation tonometer). Systematic
examinations included the measurement of echocardiogram, height, arm span,
skull, face, jaw, tooth, breast bone, spinal column, and skin. Genomic DNA was
extracted using the phenol-chloroform extraction method for all subjects, and
sequencing was carried out on an ABI Prism 3730 Genetic Analyzer.
RESULTS: A heterozygous mutation, c.184C>T (p.Arg62Cys) in exon 2 of FBN1 was
identified in all affected members but was not found in any unaffected member of
the family. Our study presented detailed clinical manifestations, including some
novel ophthalmic findings, such as pupillary abnormality, different types of
glaucoma, and progressive hyperopia.
CONCLUSIONS: Ophthalmic findings and the p.Arg62Cys mutation of FBN1 gene were
reported in a family with early-onset isolated ectopia lentis. Ectopia lentis (EL) is a condition that can either herald underlying systemic
conditions, or be isolated. The recent expansion in the genetics of these
conditions has furthered the understanding of the underlying molecular
aetiology. It is becoming apparent that novel genes, and in particular the
ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family,
are important in ocular development. The common link in these genes seems to be
EL. The clinical management of EL is challenging. In particular, the options for
addressing surgically induced aphakia in the context of an ectopic capsule are
varied. Little evidence exists to direct management of these issues. This review
summarises the molecular pathogenesis of EL and conditions associated with it,
using the genetic aetiology as a framework. Furthermore, it summarises some of
the issues involved in its clinical management. Isolated ectopia lentis is usually autosomal domit and commonly due to the
mutations of FBN1 gene. We report on a family with ectopia lentis. The
propositus is a 6-year-old boy with bilateral superior-temporal ectopia lentis.
His echocardiogram was normal and he did not meet the revised Ghent criteria for
Marfan syndrome. Molecular genetic testing revealed c.1948 C>T (p.Arg650Cys) in
FBN1. The mother has visual acuity of 20/20 with -4.50 right eye and -2.50 left
eye. She has no evidence of ectopia lentis. DNA analysis revealed that she has
the same FBN1 mutation. Seven other maternal family members also have ectopia
lentis. In conclusion, we report on a case of early-onset autosomal domit
isolated ectopia lentis caused by FBN1 mutation that has previously been
reported only in Marfan syndrome. The child's mother presumably represents a
rare case of nonpenetrance. ADAMTSL4 mutations seem to be the most common cause of isolated ectoplia lentis
(EL) and thus are important concerning the differential diagnosis of connective
tissue syndromes with EL as main feature. In this study, we describe an
additional cohort of patients with apparently isolated EL. All underwent a
detailed clinical exam with cardiac evaluation combined with ADAMTSL4 mutation
analysis. Mutations were identified in 12/15 patients with EL. Besides the
European founder mutation p. (Gln256Profs*38) we identified five further
mutations not yet described in the literature: p. (Leu249Tyrfs*21), p.
(Ala388Glyfs*8), p. (Arg746His), p. (Gly592Ser), and p. (Arg865His). Clinical
evaluation showed common additional ocular features such as high myopia, but no
major systemic findings. In particular: no dilatation of the aortic root was
reported on. This report increases the total number of patients with ADAMTSL4
mutations reported on today and reviews in detail the clinical findings in all
patients reported on to date demonstrate, that these patients have a mainly
ocular phenotype. There are no consistent systemic findings. The differentiation
between syndromic and isolated EL is crucial for the further surveillance,
treatment, and counseling of these patients, especially in young children. Author information:
(1)Medical Genetics Institute, Meir Medical Center, Kfar-Saba, Israel; Sackler
School of Medicine, Tel Aviv University, Israel. Electronic address:
[email protected].
(2)Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel
University, Ariel, Israel; Felsenstein Medical Research Center, Rabin Medical
Center, Petach Tikva, Israel.
(3)Felsenstein Medical Research Center, Rabin Medical Center, Petach Tikva,
Israel.
(4)The Raphael Recanati Genetic Institute, Rabin Medical Center, Petach Tikva,
Israel.
(5)Unit of Pediatric Ophthalmology, Wolfson Medical Center, Holon, Israel.
(6)Sackler School of Medicine, Tel Aviv University, Israel; The Genetic
Institute & Prenatal Diagnosis Unit, Tel Aviv Sourasky Medical Center, Tel Aviv,
Israel.
(7)Sackler School of Medicine, Tel Aviv University, Israel; Felsenstein Medical
Research Center, Rabin Medical Center, Petach Tikva, Israel; The Raphael
Recanati Genetic Institute, Rabin Medical Center, Petach Tikva, Israel;
Pediatric Genetics Unit, Schneider Children's Medical Center of Israel, Petach
Tikva, Israel. |
Does the word ovine refers to goats? | Ovine refers to sheep. | Bronchiolo-alveolar carcinoma has been described in man and in several animal
species, including cattle, dogs, opossums, goats and sheep. In sheep, a
bronchiolo-alveolar carcinoma, known as ovine pulmonary carcinoma (OPC), is
caused by jaagsiekte sheep retrovirus (JSRV), an exogenous type D retrovirus. In
the mid-1980s, a severe outbreak of a disease resembling OPC was described in
captive Sardinian moufflon (Ovis musimon). In the present study, the use of
polymerase chain reaction (PCR) amplification of nucleic acids extracted from
archival material established that JSRV was associated with OPC in affected
moufflon. JSRV was detected in the lungs and mediastinal lymph nodes.
Immunohistochemical and in-situ PCR demonstrated that in the lungs, JSRV
proviral DNA was localized in transformed and untransformed type II pneumocytes
and in the alveolar macrophages. In the mediastinal lymph nodes, JSRV DNA was
mainly located in the cortical follicles and paracortex. These data suggest that
JSRV is the cause of OPC in Sardinian moufflon, as it is in Sardinian sheep. Understanding the factors governing host species barriers to virus transmission
has added significantly to our appreciation of virus pathogenesis. Jaagsiekte
sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma
(OPA), a transmissible lung cancer of sheep that has rarely been found in goats.
In this study, in order to further clarify the pathogenesis of OPA, we
investigated whether goats are resistant to JSRV replication and carcinogenesis.
We found that JSRV induces lung tumors in goats with macroscopic and
histopathological features that dramatically differ from those in sheep.
However, the origins of the tumor cells in the two species are identical.
Interestingly, in experimentally infected lambs and goat kids, we revealed major
differences in the number of virus-infected cells at early stages of infection.
These differences were not related to the number of available target cells for
virus infection and cell transformation or the presence of a host-specific
immune response toward JSRV. Indeed, we also found that goats possess
transcriptionally active endogenous retroviruses (enJSRVs) that likely influence
the host immune response toward the exogenous JSRV. Overall, these results
suggest that goat cells, or at least those cells targeted for viral
carcinogenesis, are not permissive to virus replication but can be transformed
by JSRV. OBJECTIVES: Pulmonary hypertension (PHT) is associated with tricuspid annular
dilatation, but the effect of acute increase of pulmonary pressure on
three-dimensional (3D) tricuspid annular dynamics and shape is unknown. Better
understanding of tricuspid annular dynamics may lead to improved and more
durable surgical reparative techniques.
METHODS: In nine open-chest anaesthetized sheep nine sonomicrometry crystals
were implanted on the right ventricle while on cardiopulmonary bypass.
Additional nine crystals were implanted around the tricuspid annulus (TA) with
one crystal at each commissure defining three separate annular regions:
anterior, posterior and septal. Two additional equidistant crystals were
implanted between each commissure, creating three segments for every region.
Pressure transducers were placed in the left ventricular (LV), right ventricular
(RV) and right atrium. PHT was induced by acute pulmonary artery constriction
with a pneumatic occluder. Sonomicrometry and echocardiographic data were
collected before and after induction of PHT. TA area, regional and total
perimeter, and 3D annular geometry were calculated from 3D crystal coordinates.
Regional annular contraction was defined as the percentage difference between
maximal and minimal region length during the cardiac cycle.
RESULTS: PHT increased RV pressure from 31 ± 9 mmHg to 46 ± 13 mmHg (P = 0.001)
and decreased left ventricular (LV) pressure from 111 ± 24 mmHg to 78 ± 36 mmHg
(P = 0.018). There was no significant tricuspid regurgitation observed with PHT.
During PHT, the TA area increased by 12 ± 13% from 641 ± 139 mm(2) to 721 ± 177
mm(2) (P = 0.037). The total perimeter increased from 103 ± 11 mm to 109 ± 13 mm
(P = 0.02). All annular regions dilated significantly with PHT with 8 ± 10, 5 ±
5 and 5 ± 5% increase in anterior, posterior and septal annular length,
respectively (P < 0.05). PHT reduced regional annular contraction in the
anterior region only (17 ± 7 vs 14 ± 8%; P = 0.02). The TA had a complex 3D
saddle geometry and the shape of the annulus was altered during PHT only in the
antero-posterior region.
CONCLUSIONS: The changes in tricuspid annular conformation, contractility and
its 3D geometry observed during acute ovine PHT may help in the design of new
pathology-specific tricuspid annular rings. |
Does GATA-1 regulate ribosomal protein genes? | Mutations in exon 2 interfere with the synthesis of the full-length isoform of GATA-1 and lead to the production of a shortened isoform, GATA-1s. These mutations have been found in patients with Diamond-Blackfan anemia (DBA), a congenital erythroid aplasia typically caused by mutations in genes encoding ribosomal proteins. Sixteen of the corresponding transcription factors are of particular interest, as they are housekeeping genes or show a direct link to hematopoiesis, tumorigenesis or leukemia (e.g. GATA-1/2, PU.1, MZF-1). | The balanced growth of a cell requires the integration of major systems such as
DNA replication, membrane biosynthesis, and ribosome formation. An example of
such integration is evident from our recent finding that, in Saccharomyces
cerevisiae, any failure in the secretory pathway leads to severe repression of
transcription of both rRNA and ribosomal protein genes. We have attempted to
determine the regulatory circuit(s) that connects the secretory pathway with the
transcription of ribosomal genes. Experiments show that repression does not
occur through the circuit that responds to misfolded proteins in the endoplasmic
reticulum, nor does it occur through circuits known to regulate ribosome
synthesis, e.g. the stringent response, or the cAMP pathway. Rather, it appears
to depend on a stress response at the plasma membrane that is transduced through
protein kinase C (PKC). Deletion of PKC1 relieves the repression of both
ribosomal protein and rRNA genes that occurs in response to a defect in the
secretory pathway. We propose that failure of the secretory pathway prevents the
synthesis of new plasma membrane. As protein synthesis continues, stress
develops in the plasma membrane. This stress is monitored by Pkc1p, which
initiates a signal transduction pathway that leads to repression of
transcription of the rRNA and ribosomal protein genes. The importance of the
transcription of the 137 ribosomal protein genes to the economy of the cell is
apparent from the existence of at least three distinct pathways that can effect
the repression of this set of genes. BACKGROUND: The Ribosomal protein S19 gene locus (RPS19) has been linked to two
kinds of red cell aplasia, Diamond-Blackfan Anemia (DBA) and Transient
Erythroblastopenia in Childhood (TEC). Mutations in RPS19 coding sequences have
been found in 25% of DBA patients, but not in TEC patients. It has been
suggested that non-coding RPS19 sequence variants contribute to the considerable
clinical variability in red cell aplasia. We therefore aimed at identifying
non-coding variations associated with DBA or TEC phenotypes.
METHODOLOGY/PRINCIPAL FINDINGS: We targeted a region of 19'980 bp encompassing
the RPS19 gene in a cohort of 89 DBA and TEC patients for resequencing. We
provide here a catalog of the considerable, previously unrecognized degree of
variation in this region. We identified 73 variations (65 SNPs, 8 indels) that
all are located outside of the RPS19 open reading frame, and of which 67.1% are
classified as novel. We hypothesize that specific alleles in non-coding regions
of RPS19 could alter the binding of regulatory proteins or transcription
factors. Therefore, we carried out an extensive analysis to identify
transcription factor binding sites (TFBS). A series of putative interaction
sites coincide with detected variants. Sixteen of the corresponding
transcription factors are of particular interest, as they are housekeeping genes
or show a direct link to hematopoiesis, tumorigenesis or leukemia (e.g.
GATA-1/2, PU.1, MZF-1).
CONCLUSIONS: Specific alleles at predicted TFBSs may alter the expression of
RPS19, modify an important interaction between transcription factors with
overlapping TFBS or remove an important stimulus for hematopoiesis. We suggest
that the detected interactions are of importance for hematopoiesis and could
provide new insights into individual response to treatment. Mutations in the hematopoietic transcription factor GATA-1 alter the
proliferation/differentiation of hemopoietic progenitors. Mutations in exon 2
interfere with the synthesis of the full-length isoform of GATA-1 and lead to
the production of a shortened isoform, GATA-1s. These mutations have been found
in patients with Diamond-Blackfan anemia (DBA), a congenital erythroid aplasia
typically caused by mutations in genes encoding ribosomal proteins. We sequenced
GATA-1 in 23 patients that were negative for mutations in the most frequently
mutated DBA genes. One patient showed a c.2T > C mutation in the initiation
codon leading to the loss of the full-length GATA-1 isoform. |
Which gene mutations cause the Marfan syndrome? | Marfan syndrome (MFS) is an autosomal dominant disorder caused by mutations in the fibrillin 1 gene (FBN1). | The Marfan syndrome is an autosomal domit connective tissue disorder with
pleiotropic manifestations affecting skeletal, ocular and cardiovascular
systems. Because the fibrillar collagens are major structural components of
connective tissue, the hypothesis has long been set forth that the Marfan
syndrome is a disorder of fibrillar collagen. We have investigated this
hypothesis by performing linkage studies in 12 multiplex families with the
Marfan syndrome, using restriction fragment length polymorphisms (RFLP's)
associated with 3 genes encoding chains of fibrillar collagens. The data exclude
linkage to all 3 candidate genes in 2 families and at least 1 of the candidates
is excluded in 6 additional families. Each candidate was excluded in at least 3
families. In no case was strong evidence in favor of linkage of the Marfan
syndrome to any of the 3 genes observed. These data speak against the hypothesis
that mutations in one or more of these 3 fibrillar collagens cause the classic
Marfan syndrome. Mutations in the gene encoding fibrillin-1 (FBN1), a component of the
extracellular microfibril, cause the Marfan syndrome (MFS). This statement is
supported by the observations that the classic Marfan phenotype cosegregates
with intragenic and/or flanking marker alleles in all families tested and that a
significant number of FBN1 mutations have been identified in affected
individuals. We have now devised a method to screen the entire coding sequence
and flanking splice junctions of FBN1. On completion for a panel of nine
probands with classic MFS, six new mutations were identified that accounted for
disease in seven (78%) of nine patients. Nine additional new mutations have been
characterized in the early stages of a larger screening project. These 15
mutations were equally distributed throughout the gene and, with one exception,
were specific to single families. One-third of mutations created premature
termination codons, and 6 of 15 substituted residues with putative significance
for calcium binding to epidermal growth factor (EGF)-like domains. Mutations
causing severe and rapidly progressive disease that presents in the neonatal
period can occur in a larger region of the gene than previously demonstrated,
and the nature of the mutation is as important a determit as its location, in
predisposing to this phenotype. Mutations of the fibrillin gene (FBN1) are known to cause classical Marfan's
syndrome, ectopia lentis and neonatal Marfan's syndrome. We have identified a
novel missense mutation in exon 28 of the FBN1 gene (R1170H) which is
responsible for an atypical marfanoid phenotype characterised by
dolichostenomelia and arachnodactyly. BACKGROUND: The fibrillin gene encodes a protein in the extracellular matrix,
and this protein is widely distributed in elastic tissues. The fibrillin gene is
the site of mutations causing Marfan's syndrome. This disorder shows a high
degree of clinical variability both between and within families. Each family
appears to have a unique mutation in the fibrillin gene, which precludes the
routine use of mutation screening for presymptomatic diagnosis of the disorder.
The goal of this study was to develop a widely applicable method of molecular
diagnosis.
METHODS: We used three newly characterized intragenic sites of normal DNA
repeat-sequence variation (i.e., polymorphisms) as markers to follow the
inheritance pattern of specific copies (alleles) of the fibrillin gene in
multiple kindreds with various clinical features of Marfan's syndrome.
RESULTS: The polymorphic markers allowed identification of the particular copy
of the fibrillin gene that cosegregated with Marfan's syndrome in 13 of the 14
families tested. In 11 families a definite presymptomatic diagnosis of Marfan's
syndrome could be made in family members who had only equivocal manifestations
of the disorder. In two other families, some family members demonstrated either
classic Marfan's syndrome or a milder but closely related phenotype. The copy of
the fibrillin gene that cosegregated with classic Marfan's syndrome was not
inherited by family members with the latter, atypical, form of the disease.
These milder phenotypes, previously diagnosed as Marfan's syndrome, were not
associated with aortic involvement.
CONCLUSIONS: These results document the usefulness of novel polymorphic DNA
repeat sequences in the presymptomatic diagnosis of Marfan's syndrome. Our
findings also demonstrate that the various clinical phenotypes seen in selected
families may be due not to single fibrillin mutations, but rather to different
genetic alterations. These findings underscore the need for a modification of
the current diagnostic criteria for Marfan's syndrome in order to achieve
accurate risk assessment. The Marfan syndrome is an autosomal domit disorder with pleiotropic
manifestations that involve the cardiovascular, ocular, and skeletal systems.
Through a number of investigational approaches, the gene encoding for fibrillin,
the FBN1 gene on chromosome 15, has been identified as the defective gene
causing the Marfan syndrome. Fibrillin is the large glycoprotein with a
repetitive domain structure and is a major protein component of microfibrils, a
fibrillar system closely associated with elastin in connective tissue.
Mutational analysis of defects in the FBN1 gene in patients with the Marfan
syndrome has revealed that most mutations are private or unique in an affected
individual or family. Analysis of fibrillin protein or gene defects in
individuals with related phenotypes has revealed that a perinatal lethal
syndrome, termed neonatal Marfan syndrome, is due to FBN1 gene mutations. In
addition, fibroblast cell strains from a subset of patients with idiopathic
scoliosis have fibrillin protein defects. Last, fibroblasts from calves affected
with bovine Marfan syndrome display defects in the fibrillin protein. These
studies have wide-ranging implications in the diagnosis, treatment, and
prevention of Marfan syndrome and related disorders. The elastic properties of many tissues such as the lung, dermis, and large blood
vessels are due to the presence of elastic fibers in the extracellular space.
These fibers have been shown by biochemical and ultrastructural analysis to be
composed of two distinct components, a more abundant amorphous component and a
10-12 nm microfibrillar component, which is located primarily around the
periphery of the amorphous component. The protein elastin makes up the highly
insoluble amorphous component and is responsible for the elastic properties.
Elastin is found throughout the vertebrate kingdom and possesses an unusual
chemical composition rich in glycine, proline, and hydrophobic amino acids,
consot with its characteristic physical properties. The 72-kDa biosynthetic
precursor, tropoelastin, is secreted into the extracellular space where it
becomes highly cross-linked into a rubber-like network through the activity of
the copper-requiring enzyme lysyl oxidase. Analysis of the elastin gene has
demonstrated that hydrophobic and cross-linking domains are encoded in separate
exons and that there is significant alternative splicing, resulting in multiple
isoforms of tropoelastin. The elastin gene promoter contains many potential
binding sites for various modulating factors indicative of a complex pattern of
transcriptional regulation. The microfibrils contain several proteins, including
fibrillin, and probably act as an organizing scaffold in the formation of the
elastin network. There appears to be a fibrillin gene family in which each
protein contains multiple repeats of a motif previously found in epidermal
growth factor and a second motif observed in transforming growth factor beta
1-binding protein. Mutations in the fibrillin gene located on human chromosome
15 have been strongly implicated as the cause of the Marfan syndrome. The presence of elastic fibres in the extracellular matrix (ECM) provides
physiologically important elastic properties for many tissues. Until recently,
microfibrils, one component of the ECM, were thought primarily to serve as a
scaffolding on which elastin is deposited during development to form elaunin
fibres [1]. The most prominent protein that forms mammalian microfibrils is
fibrillin. It is known that mutations in the fibrillin gene cause a heterogenous
connective tissue disease called Marfan syndrome [2], so information on
mechanical properties of microfibrils or their role in tissue function would be
useful. Microfibrils are also found in the ECM of some invertebrate tissues, and
there is growing evidence that the protein forming the structure is homologous
to mammalian fibrillin [3,4]. It has been shown that the microfibril-based
arterial wall of the lobster has viscoelastic properties [5], and we have now
utilized this primitive artery to measure the modulus of elasticity of
microfibrils. It is similar to that of the rubber-like protein elastin. BACKGROUND: Mutations in the FBN1 gene are the cause of the Marfan syndrome, an
autosomal domit disorder with skeletal, ocular, and cardiovascular
complications. Aneurysms or dissections of the ascending thoracic aorta are the
major cardiovascular complications of the disorder. We tested the hypothesis
that FBN1 mutations cause thoracic aortic aneurysms or dissections in patients
who do not have the Marfan syndrome.
METHODS AND RESULTS: The FBN1 gene was screened for mutations by use of genomic
DNA from two patients with thoracic aortic aneurysms who did not have the Marfan
syndrome. Individual FBN1 exons were amplified with intron-based exon-specific
primers; the DNA fragments were screened for mutations using single-stranded
conformational polymorphism analysis; and aberrantly migrating bands were
sequenced directly. We identified a missense mutation in one patient, D1155N in
exon 27. Dermal fibroblasts from the affected individual were used to study the
effect of the missense mutation D1155N on fibrillin-1 cellular processing. The
mutation decreased the amount of fibrillin-1 deposited into the pericellular
matrix. A second putative FBN1 mutation was identified in the second patient,
P1837S in exon 44. Although this alteration was not observed in 234 chromosomes
from unrelated individuals, the alteration may represent a rare polymorphism.
CONCLUSIONS: Results of these studies support the hypothesis that FBN1 mutations
cause thoracic aortic aneurysms in patients who do not have the Marfan syndrome.
This information is important for understanding the pathogenesis of aortic
aneurysms and identification of individuals at risk for developing thoracic
aortic aneurysms or dissections. Two inherited disorders of connective tissue have major cardiovascular
complications, Marfan syndrome and Ehlers-Danlos syndrome type IV. Major
progress has been made toward understanding both the genetic defect and the
molecular pathogenesis of these two disorders. Marfan syndrome results from
mutations in the FBN1 gene, which encodes fibrillin-1, an extracellular matrix
component found in structures called microfibrils. Histologic characterization
of the effect of FBN1 mutations on fibrillin-1 cellular processing and
microfibril formation has provided insights into fibrillin-1 function.
Ehlers-Danlos syndrome type IV results from mutations in the COL3A1 gene, which
encodes the polypeptides in type III collagen. Despite advances in the molecular
genetics of these two disorders, there is not a molecular diagnostic test for
these syndromes based on the identification of gene mutations. Marfan syndrome
remains primarily a clinical diagnosis. Biochemical analysis of the amount of
type III collagen produced by dermal fibroblasts has proven to be a powerful
diagnostic test for Ehlers-Danlos syndrome type IV. The neonatal Marfan syndrome is an autosomal domitly inherited disease with
an extremely poor prognosis. This report gives a clinical and echocardiographic
description of an infant with a mutation in exon 29 of the fibrillin-1 gene
(FBN1), a region in which this severe form of Marfan syndrome seems to cluster.
The infant died at the age of 3 months due to severe acute mitral regurgitation
leading to intractable heart failure. Mutations in the gene for fibrillin-1 (FBN1) have been shown to cause Marfan
syndrome, an autosomal domit disorder of connective tissue characterised by
pleiotropic manifestations involving primarily the ocular, skeletal, and
cardiovascular systems. Fibrillin-1 is a major component of the 10-12 nm
microfibrils, which are thought to play a role in tropoelastin deposition and
elastic fibre formation in addition to possessing an anchoring function in some
tissues. Fibrillin-1 mutations have also been found in patients who do not
fulfil clinical criteria for the diagnosis of Marfan syndrome, but have related
disorders of connective tissue, such as isolated ectopia lentis, familial aortic
aneurysm, and Marfan-like skeletal abnormalities, so that Marfan syndrome may be
regarded as one of a range of type 1 fibrillinopathies. There appear to be no
particular hot spots since mutations are found throughout the entire fibrillin-1
gene. However, a clustering of mutations associated with the most severe form of
Marfan syndrome, neonatal Marfan syndrome, has been noted in a region
encompassing exons 24 to 32. The gene for fibrillin-2 (FBN2) is highly
homologous to FBN1, and mutations in FBN2 have been shown to cause a
phenotypically related disorder termed congenital contractural arachnodactyly.
Since mutations in the fibrillin genes are likely to affect the global function
of the microfibrils, the term microfibrillopathy may be the most appropriate to
designate the spectrum of disease associated with dysfunction of these
molecules. The understanding of the global and the molecular functions of the
fibrillin containing microfibrils is still incomplete and, correspondingly, no
comprehensive theory of the pathogenesis of Marfan syndrome has emerged to date.
Many, but not all, fibrillin-1 gene mutations are expected to exert a domit
negative effect, whereby mutant fibrillin monomers impair the global function of
the microfibrils. In this paper we review the molecular physiology and
pathophysiology of Marfan syndrome and related microfibrillopathies. Marfan Syndrome (MfS) is an autosomal domit inherited connective tissue
disorder with variable phenotypic expression of cardiovascular, skeletal and
ocular manifestations. Cardiovascular complications, such as aortic aneurysm and
dissection drastically reduce life expectancy of individuals with MfS, whereas
preventive surgery substantially improves the prognosis of these patients. A
number of mutations in the fibrillin 1 (FBN1) gene associated with MfS have been
identified to date, demonstrating considerable molecular heterogeneity. One
region, however, located around exon 24, exhibits a striking clustering of
mutations, which are associated with a severe, socalled neonatal form of MfS.
Here we report the first mutation (G2950A) in exon 24 of the neonatal region of
the FBN1 gene, associated with a classic MfS phenotype. The mutation leads to
the subsitution of valin by isoleucin (V984I), both uncharged amino acids, which
only differ in a single methyl group. This defect was identified in a proband
with cardiovascular manifestations of MfS by SSCP analysis of PCR-amplified
genomic DNA, direct PCR sequencing and RFLP analysis. The substitution was
neither detected in the unaffected 4-year old daughter of the proband, nor in 3
of his healthy family members nor in 108 allels from control individuals,
suggesting that this mutation is causative for MfS in the patient. Since no
other family member of the proband is affected by MfS, the defect described is
sporadic. In summary, we identified a novel defect in exon 24 of the neonatal
region of the FBN1 gene in a patient with a classic phenotype of MfS, suggesting
that conservative substitutions in this region may lead to a less severe
phenotype of the disease. This finding further demonstrates the remarkable
phenotypic heterogeneity associated with FBN1 mutations and stresses the
significance of modifying genes and individual alterations in protein function
for the pheontypic expression of the disease. Mutations in the gene for fibrillin-1 (FBN1) cause Marfan syndrome, a domitly
inherited disorder of connective tissue that primarily involves the
cardiovascular, ocular, and skeletal systems. There is a remarkable degree of
variability both within and between families with Marfan syndrome, and FBN1
mutations have also been found in a range of other related connective tissue
disorders collectively termed type-1 fibrillinopathies. FBN1 mutations have been
found in almost all of the 65 exons of the FBN1 gene and for the most part have
been unique to one affected patient or family. Aside from the "hot spots" for
the neonatal Marfan syndrome in exons 24-27 and 31-32, genotype-phenotype
correlations have been slow to emerge. Here we present the results of
temperature-gradient gel electrophoresis analysis of FBN1 exons 59-65. Six
mutations were identified, only one of which had been previously reported. Two
of the six mutations were found in patients with mild phenotypes. Taken together
with other published reports, our results suggest that a sizable subset (ca.
40%) of mutations in this region is associated with mild phenotypes
characterized by the lack of significant aortic pathology, compared with about
7% in the rest of the gene. In two cases, mutations affecting analogous
positions within one of the 43 cbEGF modules of FBN1 are associated with mild
phenotypes when found in one of the 6 C-terminal modules (encoded by exons
59-63), but are associated with classic or severe phenotypes when found in cbEGF
modules elsewhere in the gene. Most extracellular proteins consist of various modules with distinct functions.
Mutations in one common type, the calcium-binding epidermal growth factor-like
module (cbEGF), can lead to a variety of genetic disorders. Here, we describe as
a model system structural and functional consequences of two typical mutations
in cbEGF modules of fibrillin-1 (N548I, E1073K), resulting in the Marfan
syndrome. Large (80-120 kDa) wild-type and mutated polypeptides were
recombitly expressed in mammalian cells. Both mutations did not alter
synthesis and secretion of the polypeptides into the culture medium. Electron
microscopy after rotary shadowing and comparison of circular dichroism spectra
exhibited minor structural differences between the wild-type and mutated forms.
The mutated polypeptides were significantly more susceptible to proteolytic
degradation by a variety of proteases as compared with their wild-type
counterparts. Most of the sensitive cleavage sites were mapped close to the
mutations, indicating local structural changes within the mutated cbEGF modules.
Other cleavage sites, however, were observed at distances beyond the domain
containing the mutation, suggesting longer range structural effects within
tandemly repeated cbEGF modules. We suggest that proteolytic degradation of
mutated fibrillin-1 may play an important role in the pathogenesis of Marfan
syndrome and related disorders. Mutations in the gene for fibrillin-1 (FBN1) cause Marfan syndrome, an autosomal
domit disorder of connective tissue with prominent manifestations in the
skeletal, ocular, and cardiovascular system. There is a remarkable degree of
clinical variability both within and between families with Marfan syndrome as
well as in individuals with related disorders of connective tissue caused by
FBN1 mutations and collectively termed type-1 fibrillinopathies. The so-called
neonatal region in FBN1 exons 24-32 comprises one of the few generally accepted
genotype-phenotype correlations described to date. In this work, we report 12
FBN1 mutations identified by temperature-gradient gel electrophoresis screening
of exons 24-40 in 127 individuals with Marfan syndrome or related disorders. The
data reported here, together with other published reports, document a
significant clustering of mutations in exons 24-32. Although all reported
mutations associated with neonatal Marfan syndrome and the majority of point
mutations associated with atypically severe presentations have been found in
exons 24-32, mutations associated with classic Marfan syndrome occur in this
region as well. It is not possible to predict whether a given mutation in exons
24-32 will be associated with classic, atypically severe, or neonatal Marfan
syndrome. OBJECTIVE: It has been firmly established that mutations in the gene for
fibrillin 1, FBN1, cause Marfan syndrome (MFS). FBN1 mutations can also cause
other phenotypes, such as ectopia lentis (EL) and familial isolated thoracic
aortic aneurysm and dissection (FAA). When the clinical presentation is typical,
diagnosis of MFS is usually easy to make. However, there can be a marked
phenotypic variation between affected subjects even in one family, and making
the diagnosis can be challenging, especially in childhood. The objective of this
study was to test the sensitivity of conformation sensitive gel electrophoresis
(CSGE) for detecting mutations in FBN1 in MFS and related phenotypes.
DESIGN: Setting up CSGE analysis for the FBN1 gene and testing the method first
by screening coded samples from 17 MFS patients with previously detected FBN1
mutations. We then used a test set consisting of 46 coded samples representing
MFS, related phenotypes, and controls.
RESULTS: Sixteen of the 17 known mutations were detected. Altogether 23
mutations were detected in a test set consisting of 46 coded samples
representing MFS, related phenotypes, and controls. Nineteen of the mutations
were novel. The mutation was detected in 18 of the 20 MFS patients and in one
patient with familial EL, but not in a patient with sporadic MASS syndrome, any
of the five sporadic annuloaortic ectasia (AAE) patients, or any of the 15
controls. A FBN1 mutation was detected in four members of a multigeneration
family with AAE, however.
CONCLUSIONS: These results indicate that CSGE is highly sensitive for the
detection of mutations in FBN1, and that molecular diagnostics is a useful means
of confirming clinical diagnoses of MFS and related disorders. Further careful
investigations are needed, however, in order to correlate the interfamilial and
intrafamilial clinical variabilities of fibrillinopathies and mutations in FBN1. Mutations in the gene encoding fibrillin-1 (FBN1) cause Marfan syndrome (MFS)
and other related connective tissue disorders. In this study we performed SSCP
to analyze all 65 exons of the FBN1 gene in 76 patients presenting with
classical MFS or related phenotypes. We report 7 missense mutations, 3 splice
site alterations, one indel mutation, one nonsense mutation and two mutations
causing frameshifts: a 16bp deletion and a single nucleotide insertion. 5 of the
missense mutations (Y1101C, C1806Y, T1908I, G1919D, C2251R) occur in
calcium-binding Epidermal Growth Factor-like (EGFcb) domains of exons 26, 43, 46
and 55, respectively. One missense mutation (V449I) substitutes a valine residue
in the non-calcium-binding epidermal growth factor like domain (EGFncb) of exon
11. One missense mutation (G880S) affects the "hybrid" motif in exon 21 by
replacing glycine to serine. The 3 splice site mutations detected are: IVS1-1G>A
in intron 1, IVS38-1G>A in intron 38 and IVS46+5G>A in intron 46. C628delinsK
was identified in exon 15 leading to the substitution of a conserved cysteine
residue. Furthermore two frameshift mutations were found in exon 15
(1904-1919del ) and exon 63 (8025insC) leading to premature termination codons
(PTCs) in exon 17 and 64 respectively. Finally we identified a nonsense mutation
(R429X) located in the proline rich domain in exon 10 of the FBN1 gene. Y1101C,
IVS46+5G>A and R429X have been reported before. Fibrillin-1 is a mosaic protein mainly composed of 43 calcium binding epidermal
growth factor-like (cbEGF) domains arranged as multiple, tandem repeats.
Mutations within the fibrillin-1 gene cause Marfan syndrome (MFS), a heritable
disease of connective tissue. More than 60% of MFS-causing mutations identified
are localized to cbEGFs, emphasizing that the native properties of these domains
are critical for fibrillin-1 function. The cbEGF12-13 domain pair is within the
longest run of cbEGFs, and many mutations that cluster in this region are
associated with severe, neonatal MFS. The NMR solution structure of
Ca(2+)-loaded cbEGF12-13 exhibits a near-linear, rod-like arrangement of
domains. This observation supports the hypothesis that all fibrillin-1
(cb)EGF-cbEGF pairs, characterized by a single interdomain linker residue,
possess this rod-like structure. The domain arrangement of cbEGF12-13 is
stabilized by additional interdomain packing interactions to those observed for
cbEGF32-33, which may help to explain the previously reported higher calcium
binding affinity of cbEGF13. Based on this structure, a model of cbEGF11-15 that
encompasses all known neonatal MFS missense mutations has highlighted a
potential binding region. Backbone dynamics data confirm the extended structure
of cbEGF12-13 and lend support to the hypothesis that a correlation exists
between backbone flexibility and cbEGF domain calcium affinity. These results
provide important insight into the potential consequences of MFS-associated
mutations for the assembly and biomechanical properties of connective tissue
microfibrils. Fibrillin-1 is a large modular glycoprotein that assembles to form 10-12 nm
microfibrils in the extracellular matrix. Mutations in the fibrillin-1 gene
(FBN1) cause Marfan syndrome and related connective tissue disorders
(fibrillinopathies) that show autosomal domit inheritance. The pathogenic
mechanism is thought to be a domit negative effect of a mutant protein on
microfibril assembly, although direct evidence is lacking. A significant group
of disease-causing FBN1 mutations are cysteine substitutions within EGF domains
that are predicted to cause misfolding by removal of disulphide bonds that
stabilize the native domain fold. We have studied three missense mutations
(C1117Y, C1129Y and G1127S) to investigate the effect of misfolding on the
trafficking of fibrillin-1 from fibroblast cells. We demonstrate that both
C1117Y and C1129Y, expressed as recombit fragments of fibrillin-1, are
retained and accumulate within the cell. Both undergo core glycosylation but
lack the complex glycosylation observed in the secreted wild-type fragment,
suggesting retention in the endoplasmic reticulum (ER). In addition,
co-immunoprecipitation experiments show association with the ER chaperone
calreticulin, but not calnexin, 78 kDa glucose-regulated protein (Grp78/BiP) or
protein disulfide isomerase. In contrast, G1127S, which causes a moderate change
in the EGF domain fold, shows a pattern of glycosylation and trafficking profile
indistinguishable from the wild-type fragment. Since expression of the
recombit fragments does not disrupt the secretion of endogenous fibrillin-1
by the cell, we propose that G1127S causes disease via an extracellular domit
negative effect. In contrast, the observed ER retention of C1117Y and C1129Y
suggests that disease associated with these missense mutations is caused either
by an intracellular domit negative effect or haploinsufficiency. Neonatal Marfan syndrome caused by an exon 25 mutation of the Fibrillin-1 gene:
We describe a male infant with severe arachnodactyly, hypermobility of the
fingers, flexion contractures of elbows, wrists, hips, and knees,
microretrognathia, crumpled ears, rockerbottom feet, loose redundant skin, and
lens dislocations. Cardiac valve insufficiency and aortic dilatation resulted in
cardiac failure, decompensated with digitalisation and death occurred at the age
of 4 months. This case represents the severe end of the clinical spectrum of
Marfan syndrome, namely neonatal Marfan syndrome. Molecular diagnostic analyses
confirmed a de novo exon 25 mutation in the FBN1 gene. PURPOSE OF REVIEW: Marfan syndrome, the founding member of connective tissue
disorders, is characterized by involvement of three major systems (skeletal,
ocular, and cardiovascular) due to alteration in microfibrils. FBN1 at 15q21.1
was found to cause Marfan syndrome in 1991, and in 2004 TGFBR2 at 3p24.1 was
newly identified as the Marfan syndrome type II gene. Several studies implied
that fibrillin-1 and transforming growth factor-beta (TGF-beta) signaling are
functionally related in extracellular matrix. Identification of TGFBR2 mutations
in Marfan syndrome type II provided the direct evidence of the relation in
humans.
RECENT FINDINGS: More than 500 FBN1 mutations have been found in Marfan
syndrome, tentative genotype - phenotype correlations have emerged, and mouse
models are providing insight into pathogenic mechanisms. TGFBR2 mutations are
still limited, however, in 2005 were also reported to cause a new aneurysm
syndrome. Functional association between fibrillin-1 and TGF-beta signaling in
extracellular matrix has been presented.
SUMMARY: This review focuses on recent molecular genetics advances in Marfan
syndrome and overlapping connective tissue disorders. Mutation spectrum of FBN1
and TGFBR2 in relation to phenotype is presented. Functional relation between
fibrillin-1 and TGF-beta signaling is discussed. Future prospects in the study
of Marfan syndrome are presented. Marfan syndrome (MFS) is an autosomal domit connective tissue disorder
characterized by manifestations in the cardiovascular, skeletal, ocular, and
other organ systems. MFS type1 (MFS1) is caused by mutations in the gene
encoding fibrillin (FBN1). Recently, the transforming growth factor-beta
receptor-2 gene, TGFBR2, has been shown to be associated with a second type of
this disorder with typically mild or absent ocular involvement (MFS type 2;
MFS2). Several point mutations were found in the highly conserved
serine/threonine kinase domain of TGFBR2. Mutations in both TGFBR1 and TGFBR2
are associated with Loeys-Dietz aortic aneurysm syndrome (LDS). We searched for
TGFBR1 and TGFBR2 mutations in 41 unrelated patients fulfilling the diagnostic
criteria of Ghent nosology or with the tentative diagnosis of Marfan syndrome,
in whom mutations in the FBN1 coding region were not identified. In TGFBR1, two
mutations and two polymorphisms were detected. In TGFBR2, five mutations and six
polymorphisms were identified. Reexamination of patients with a TGFBR1 or TGFBR2
mutation revealed extensive clinical overlap between patients with MFS1, MFS2,
and LDS. Mutations in the fibrillin-1 (FBN1) gene cause Marfan syndrome (MFS) and have
been associated with a wide range of overlapping phenotypes. Clinical care is
complicated by variable age at onset and the wide range of severity of aortic
features. The factors that modulate phenotypical severity, both among and within
families, remain to be determined. The availability of international FBN1
mutation Universal Mutation Database (UMD-FBN1) has allowed us to perform the
largest collaborative study ever reported, to investigate the correlation
between the FBN1 genotype and the nature and severity of the clinical phenotype.
A range of qualitative and quantitative clinical parameters (skeletal,
cardiovascular, ophthalmologic, skin, pulmonary, and dural) was compared for
different classes of mutation (types and locations) in 1,013 probands with a
pathogenic FBN1 mutation. A higher probability of ectopia lentis was found for
patients with a missense mutation substituting or producing a cysteine, when
compared with other missense mutations. Patients with an FBN1 premature
termination codon had a more severe skeletal and skin phenotype than did
patients with an inframe mutation. Mutations in exons 24-32 were associated with
a more severe and complete phenotype, including younger age at diagnosis of type
I fibrillinopathy and higher probability of developing ectopia lentis, ascending
aortic dilatation, aortic surgery, mitral valve abnormalities, scoliosis, and
shorter survival; the majority of these results were replicated even when cases
of neonatal MFS were excluded. These correlations, found between different
mutation types and clinical manifestations, might be explained by different
underlying genetic mechanisms (domit negative versus haploinsufficiency) and
by consideration of the two main physiological functions of fibrillin-1
(structural versus mediator of TGF beta signalling). Exon 24-32 mutations define
a high-risk group for cardiac manifestations associated with severe prognosis at
all ages. Marfan syndrome is a well-described autosomal domit syndrome with widely
variable clinical manifestations. Cardiovascular complications include mitral
valve prolapse with or without associated mitral valve insufficiency, aortic
root dilatation, and most importantly the occasional development of aortic
aneurysms or rupture. Given the inconsistent phenotype along with the
potentially life-threatening implications, clinicians are increasingly turning
to genetic testing for definitive diagnostic confirmation. It has been well
established that mutations in the FBN1 gene encoding the structural protein
Fibrillin 1 is the molecular etiology of Marfan syndrome. However, there are
numerous patients who meet the Ghent clinical diagnostic criteria for Marfan
syndrome who do not have identifiable FBN1 mutations. Recently, mutations in
TGFBR1 and TGFBR2 (transforming growth factor beta receptors 1 and 2,
respectively) have been shown to result in Loeys-Dietz syndrome, a connective
tissue disorder with significant phenotypic overlap with Marfan syndrome.
Individuals with this Marfanoid disorder lack the ocular findings of Marfan
syndrome and often have dysmorphic features such as unusual facies, cleft
palate, and contractures. In addition, Loeys-Dietz syndrome patients often
present in childhood with significant cardiovascular problems. This article
serves to report an illustrative case of Loeys-Dietz syndrome and reviews the
phenotypic consequences of FBN1 and TGFBR1 and TGFBR2 gene mutations. Neonatal Marfan syndrome is a severe form of the syndrome mostly caused by
de-novo mutations in the fibrillin-1 gene. We report a newborn with neonatal
Marfan syndrome and functional pulmonary atresia who died from congestive heart
failure on postnatal day 22 despite treatment. He had a mutation in exon 29 of
the fibrillin-1 gene at position c.3602G>A. Functional pulmonary atresia may be
a life-threatening cardiovascular manifestation of neonatal Marfan syndrome. Marfan syndrome is an autosomal domit condition, with manifestations mainly
in the skeletal, ocular, and cardiovascular systems. The disorder is caused by
mutations in fibrillin-1 gene (FBN1). The majority of these are family-specific
point mutations, with a small number being predicted to cause exon-skipping. To
date, there have only been five reports of in-frame exon deletions in FBN1, with
the largest of these spanning three exons. Mosaicism is rarely recorded and has
only been reported in the unaffected, or mildly affected, parents of probands.
Here, we report on the clinical histories of two children with exon deletions in
FBN1. Both have severe Marfan syndrome with significant signs in infancy. One
patient has a deletion of exon 33, which has not previously been reported. The
other has the largest reported deletion, which spans 37 exons, and also
represents the first reported case of mosaicism in a patient with Marfan
syndrome. Fibrillin-1 gene (FBN1) mutations cause Marfan syndrome (MFS), an inherited
connective tissue disorder with autosomal domit transmission. Major clinical
manifestations affect cardiovascular and skeletal apparatuses and ocular and
central nervous systems. We analyzed FBN1 gene in 99 patients referred to our
Center for Marfan Syndrome and Related Disorders (University of Florence,
Florence, Italy): 85 were affected by MFS and 14 by other fibrillinopathies type
I. We identified mutations in 80 patients. Among the 77 different mutational
events, 46 had not been previously reported. They are represented by 49 missense
(61%), 1 silent (1%), 13 nonsense (16%), 6 donor splice site mutations (8%), 8
small deletions (10%), and 3 small duplications (4%). The majority of missense
mutations were within the calcium-binding epidermal growth factor-like domains.
We found preferential associations between The Cys-missense mutations and
ectopia lentis and premature termination codon mutations and skeletal
manifestations. In contrast to what reported in literature, the cardiovascular
system is severely affected also in patients carrying mutations in exons 1-10
and 59-65. In conclusion, we were able to detect FBN1 mutations in 88% of
patients with MFS and in 36% of patients with other fibrillinopathies type I,
confirming that FBN1 mutations are good predictors of classic MFS. Marfan syndrome is an autosomal domit disorder involving different organ
systems. Marfan syndrome type 1 (MFS1) is caused by mutations in the FBN1 gene.
Heterozygosity for mutations in the TGFBR1 or TGFBR2 genes cause Loeys-Dietz
syndrome (LDS) types 2A and 2B that overlap with MFS1 in their clinical
features. The phenotype of MFS1 is defined by the Ghent nosology, which
classifies the clinical manifestations in major and minor criteria. Dural
ectasia is one of the major criteria for Marfan syndrome but it is rarely tested
for. We here report 22 novel and 9 recurrent mutations in the FBN1 gene in 36
patients with clinical features of Marfan syndrome. Sixty patients with
identified mutations in the FBN1 gene and three patients with mutations in the
TGFBR1 or TGFBR2 genes were examined for dural ectasia. Forty-seven of the 60
patients (78%) with MFS1 showed the dural ectasia criterion and 13 (22%) did
not. Thirty-three (55%) patients were suspected of having Marfan syndrome and 24
(73%) of them had dural ectasia. Two of the three patients with LDS had dural
ectasia. Mutations in the gene encoding fibrillin 1 (FBN1) cause Marfan syndrome (MFS),
and related connective tissue disorders. The disease spectrum is wide and while
many genotype-phenotype correlations have been reported, few have been
consistent. In this study FBN1 was analyzed in 113 patients with MFS or
Marfan-like features. Fifty-three mutations were identified in 52 individuals,
41 of which were novel. The mutations comprised 26 missense, 11 splice site, 7
frameshift, 6 nonsense, 1 in-frame deletion, and 2 whole exon deletions. In
common with previous studies, genotype-phenotype analysis showed that a FBN1
mutation was more likely to be identified in patients fulfilling Ghent criteria
(P = 0.005) and in those who had ectopia lentis (EL) (P < 0.0001). Other
previously reported genotype-phenotype correlations were also considered and a
new inverse association between a mutation in exons 59-65, and EL emerged (P =
0.002). Marfan syndrome has been associated with approximately 562 mutations in the
fibrillin-1 (FBN1) gene. Mutation scanning of the FBN1 gene with DNA direct
sequencing is time-consuming and expensive because of its large size. This study
analyzed the diagnostic value of high-resolution melting analysis as an
alternative method for scanning of the FBN1 gene. A total of 75 polymerase chain
reaction (PCR) amplicons (179-301bp, average 256bp) that covered the complete
coding regions and splicing sites were evaluated on the 96-well LightCycler
system. Melting curves were analyzed as fluorescence derivative plots (-dF/dT
vs. temperature). To determine the sensitivity of this method, a total of 82
samples from patients with Marfan syndrome and 50 unaffected individuals were
analyzed. All mutations reported in this study had been confirmed previously by
direct sequencing analysis. Melting analysis identified 48 heterozygous
variants. The variant c.3093 G>T (exon 25) was incorrectly identified by melting
curve analysis. The sensitivity of the technique in this sample was 98.78%
(81/82). This study demonstrated that high-resolution melting analysis is a
reliable gene scanning method with greater speed than DNA sequencing. Our
results support the use of this technology as an alternative method for the
diagnosis of Marfan syndrome as well as its suitability for high-throughput
mutation scanning of other large genes. Mutations in the FBN1 gene cause Marfan syndrome (MFS) and have been associated
with a wide range of milder overlapping phenotypes. A proportion of patients
carrying a FBN1 mutation does not meet diagnostic criteria for MFS, and are
diagnosed with "other type I fibrillinopathy." In order to better describe this
entity, we analyzed a subgroup of 146 out of 689 adult propositi with incomplete
"clinical" international criteria (Ghent nosology) from a large collaborative
international study including 1,009 propositi with a pathogenic FBN1 mutation.
We focused on patients with only one major clinical criterion, [including
isolated ectopia lentis (EL; 12 patients), isolated ascending aortic dilatation
(17 patients), and isolated major skeletal manifestations (1 patient)] or with
no major criterion but only minor criteria in 1 or more organ systems (16
patients). At least one component of the Ghent nosology, insufficient alone to
make a minor criterion, was found in the majority of patients with isolated
ascending aortic dilatation and isolated EL. In patients with isolated EL,
missense mutations involving a cysteine were predomit, mutations in exons
24-32 were underrepresented, and no mutations leading to a premature truncation
were found. Studies of recurrent mutations and affected family members of
propositi with only one major clinical criterion argue for a clinical continuum
between such phenotypes and classical MFS. Using strict definitions, we conclude
that patients with FBN1 mutation and only one major clinical criterion or with
only minor clinical criteria of one or more organ system do exist but represent
only 5% of the adult cohort. The aim of this study was to establish a national database of mutations in the
fibrillin-1 (FBN1) gene that cause Marfan syndrome (MFS) in the Taiwanese
population. In this study, we screened 294 patients from 157 families for the
presence of FBN1 mutations using polymerase chain reaction/ denaturing high
performance liquid chromatography (PCR/DHPLC). We identified 56 mutations in 62
of the 157 (40%) families including 49 single-base substitutions (36 missense
mutations, seven nonsense mutations, and six splicing sites), one small
insertion, four small deletions, one small indel (insertion and deletion), and
one exonic deletion (Exon 36). When family history was taken into consideration,
the mutation detection rate rose to 91% (29 of 32). We further investigated the
phenotypic data and found that one third (47 of 157) of the families fit the
Ghent criteria for MFS. Based on that data, the mutation rate was 98% (46/47).
That finding implies that family history and the Ghent criteria play a more
important role than clinical manifestations in establishing a clinical diagnosis
of Marfan syndrome. Among the 56 mutations found in this study, 40 (71%) have
not been registered in the Human Gene Mutation Database (HGMD) or in the
Universal Mutation Database (UMD). This is the first study of the mutation
spectrum of MFS in a cohort of patients in Taiwan. The database is expected to
considerably improve genetic counseling for and medical care of MFS families. The Fibrillin-1 gene (FBN1; chromosome 15q21.1) encodes a major glycoprotein
component of the extracellular matrix. Mutations in FBN1, TGFBR1, TGFBR2 are
known to cause Marfan syndrome (MIM 154700), a pleiotropic disorder. In the
present study, we describe five novel missense FBN1 mutations in five Marfan
patients that have the peculiarity to activate two contemporary mutational
mechanisms: a missense mutation and exon skipping. BACKGROUND: Mutations in the fibrillin-1 gene have been identified in patients
with Marfan syndrome (MFS). This study aimed to identify the molecular defects
in the fibrillin-1 gene in a Chinese family with Marfan syndrome, accompanied by
aortic aneurysms/dissection.
METHODS: Two patients and one non-carrier in the family underwent complete
physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted
from leukocytes of venous blood of these individuals in the family as well as 50
healthy normal controls. Polymerase chain reaction amplification and direct
sequencing of all 65 coding exons of fibrillin-1 gene were analyzed.
RESULTS: We found a novel mutation (c.8547T > G, p.Tyr2849X) in exon 65 of
fibrillin-1 gene in a Chinese proband with Marfan syndrome, accompanied by
aortic aneurysms/dissection. Sudden death at a young age of affected members was
seen due to aortic aneurysms/dissection. By evaluating genotype-phenotype
correlations of patients with mutations in the 3' end of fibrillin-1 gene (exons
64 and 65), we also found that the presence of nonsense mutations occurring in
exons 64 and 65 appeared to be an indicator of early-onset aortic risk and
sudden death.
CONCLUSIONS: These results expand the mutation spectrum of fibrillin-1 gene and
help in the study of the molecular pathogenesis of Marfan syndrome, indicating
that mutations occurring in the 3' end of fibrillin-1 gene may play an
independent functional role in the pathogenesis of Marfan syndrome. Although thoracic aortic aneurysms and dissections (TAAD) can be inherited as a
single-gene disorder, the genetic predisposition in the majority of affected
people is poorly understood. In a multistage genome-wide association study
(GWAS), we compared 765 individuals who had sporadic TAAD (STAAD) with 874
controls and identified common SNPs at a 15q21.1 locus that were associated with
STAAD, with odds ratios of 1.6-1.8 that achieved genome-wide significance. We
followed up 107 SNPs associated with STAAD with P < 1 × 10(-5) in the region, in
two separate STAAD cohorts. The associated SNPs fall into a large region of
linkage disequilibrium encompassing FBN1, which encodes fibrillin-1. FBN1
mutations cause Marfan syndrome, whose major cardiovascular complication is
TAAD. This study shows that common genetic variants at 15q21.1 that probably act
via FBN1 are associated with STAAD, suggesting a common pathogenesis of aortic
disease in Marfan syndrome and STAAD. Mutations in the gene encoding fibrillin-1 (FBN1), a component of the
extracellular microfibril, cause Marfan syndrome (MFS). Frequent observation of
cattle with a normal withers height, but lower body weight than age-matched
normal cattle, was recently reported among cattle sired by phenotypically normal
Bull A, in Japanese Black cattle. These cattle also showed other characteristic
features similar to the clinical phenotype of human MFS, such as a long phalanx
proximalis, oval face and crystalline lens cloudiness. We first screened a
paternal half-sib family comprising 36 affected and 10 normal offspring of Bull
A using the BovineSNP50 BeadChip (illumina). Twenty-two microsatellite markers
mapped to a significant region on BTA10 were subsequently genotyped on the
family. The bovine Marfan syndrome-like disease (MFSL) was mapped onto BTA10. As
FBN1 is located in the significant region, FBN1 was sequenced in Bull A, and
three affected and one normal cattle. A G>A mutation at the intron64 splicing
accepter site (c.8227-1G>A) was detected in 31 of 36 affected animals (84.7%).
The c.8227-1G>A polymorphism was not found in 20 normal offspring of Bull A or
in 93 normal cattle unrelated to Bull A. The mutation caused a 1-base shift of
the intron64 splicing accepter site to the 3' direction, and a 1-base deletion
in processed mRNA. This 1-base deletion creates a premature termination codon,
and a 125-amino acid shorter Fibrillin-1 protein is produced from the mutant
mRNA. We therefore conclude that the c.8227-1G>A mutation is causative for MFSL.
Furthermore, it was suggested that Bull A exhibited germline mosaicism for the
mutation, and that the frequency of the mutant sperm was 14.9%. Marfan syndrome is a multisystem disorder of connective tissue that is inherited
in an autosomal domit fashion, and results from mutation of the FBN1 gene on
human chromosome 15. There are a number of conditions of the connective tissue
with a similar phenotype that can be confused with Marfan syndrome.
Modifications of the diagnostic criteria have recently been published,
facilitating the differentiation of Marfan syndrome from these conditions. It is
still difficult to use modern genetic testing for diagnosis because Marfan
syndrome can be caused by many different mutations in FBN1, a large gene with 65
coding segments, while mutations in other genes can cause overlapping
phenotypes. Several clinical trials of drug therapy, including the
antihypertensive drug losartan, are in progress. When a known microimbalance affecting multiple genes is detected in a patient
with syndromic intellectual disability, it is usually presumed causative for all
observed features. Whole exome sequencing (WES) allows questioning this
assumption. In this study of three families with children affected by
unexplained syndromic intellectual disability, genome-wide copy number and
subsequent analyses revealed a de novo maternal 1.1 Mb microdeletion in the
14q32 imprinted region causing a paternal UPD(14)-like phenotype, and two
inherited 22q11.21 microduplications of 2.5 or 2.8 Mb. In patient 1 carrying the
14q32 microdeletion, tall stature and renal malformation were unexplained by
paternal UPD(14), and there was no altered DLK1 expression or unexpected
methylation status. By WES and filtering with a mining tool, a novel FBN1
missense variant was found in patient 1 and his mother, who both showed clinical
features of Marfan syndrome by thorough anthropometric assessment, and a novel
EYA1 missense variant as a probable cause of the renal malformation in the
patient. In patient 2 with the 22q11.21 microduplication syndrome, skin hypo-
and hyperpigmentation and two maligcies were only partially explained. By
WES, compound heterozygous BLM stop founder mutations were detected causing
Bloom syndrome. In male patient 3 carrying a 22q11.21 microduplication inherited
from his unaffected father, WES identified a novel missense variant in the OPHN1
X-linked intellectual disability gene inherited from the unaffected mother as a
possible additional cause for developmental delay. Thus, WES seems warranted in
patients carrying microdeletions or microduplications, who have unexplained
clinical features or microimbalances inherited from an unaffected parent. Marfan syndrome is an autosomal domit connective tissue disorder caused by
mutations in the fibrillin gene FBN1, which encodes an extracellular matrix
glycoprotein. Major features of Marfan syndrome occur in the ocular,
cardiovascular, and skeletal systems as well as in the dura mater. Approximately
60% of known disease-causing mutations are missense mutations of single amino
acid residues. Effects on the cardiovascular system are classically associated
with mutations in exons 24-32 of the 65 FBN1 exons and many, though not all,
reports associate missense mutations in exons 59-65 with a mild cardiovascular
phenotype. Here we present 5 related individuals among whom a c.7409G>A
(p.Cys2470Tyr) missense variant in exon 59 of FBN1 is associated with
significant cardiovascular features. The index case also had an apparently de
novo 46,XX,del(5)(q33.1q33.3) deletion on chromosome 5. This family demonstrates
skeletal, dermatological and neurological features consistent with Marfan
syndrome but lacks significant ophthalmological findings to date. These findings
suggest that FBN1 C-terminal missense mutations may not confer the
ophthalmological features of Marfan syndrome, but they also confer a more
significant risk for cardiovascular pathology than that suggested by previous
studies. Furthermore, clinical data from this family supports the previously
reported association of dural ectasia with C-terminal mutations. Marfan syndrome (MFS) is an autosomal domit disorder caused by mutations in
the fibrillin 1 gene (FBN1). Neonatal form of MFS is rare and is associated with
severe phenotype and a poor prognosis. We report on a newborn girl with neonatal
MFS who displayed cyanosis and dyspnea on the first day of life. The main
clinical features included mitral and tricuspid valve insufficiency, aortic root
dilatation, arachnodactyly, and loose skin. Despite the presence of severe and
inoperable heart anomalies, the girl was quite stable on symptomatic treatment
and lived up to the 7th month of age when she died due to cardiorespiratory
failure. Molecular-genetic studies revealed a novel intronic c.4211-32_-13del
mutation in the FBN1 gene. Subsequent in vitro splicing analysis showed this
mutation led to exon 35 skipping, presumably resulting in a deletion of 42 amino
acids (p.Leu1405_Asp1446del). Interestingly, this mutation is localized outside
the region of exons 24-32, whose mutation is responsible for the substantial
majority of cases of neonatal MFS. Although the family history of MFS was
negative, the subsequent molecular genetic examination documented a mosaicism of
the same mutation in the maternal blood cells (10-25% of genomic DNA) and the
detailed clinical examination showed unilateral lens ectopy. BACKGROUND: The studies on heart rate variability (HRV), a key predictor of
all-cause mortality, in Marfan syndrome (MS), up to now have not been reported,
especially in patients with FBN1 mutations.
METHODS: Among 18 MS patients with the phenotype of MS meeting inclusion
criteria 15 have had a FBN1 gene mutation. Short electrocardiography records
were taken in the supine position and during orthostatic tests. The control
group consisted of 30 apparently healthy nonathletes matched by age and gender.
RESULTS: Heart rates in MS patients with the FBN1 mutation were increased in
both the supine position and orthostatic test (p < 0.001). Most of the
time-domain (standard deviation, pNN50) and frequency-domain (total power, very
low, low, and high frequency) parameters of HRV were significantly reduced in
the MS patients (p < 0.001).
CONCLUSIONS: A marked decrease in HRV, documented in the study, may be an
important clinical feature in MS patients with confirmed FBN1 gene mutations. |
What is the indication of ARCALYST? | In February 2008, Regeneron received Orphan Drug approval from the Food and Drug Administration for rilonacept in the treatment of two cryopyrin-associated periodic syndromes (CAPS) disorders, namely, familial cold-induced autoinflammatory syndrome (FCAS) and Muckle-Wells syndrome (MWS), for children and adults 12 years and older. | Cryopyrin-associated periodic syndromes (CAPS) are a group of inherited
inflammatory disorders consisting of familial cold-induced autoinflammatory
syndrome (FCAS), Muckle-Wells syndrome (MWS), and neonatal-onset multisystem
inflammatory disease (NOMID; also known as chronic infantile neurologic,
cutaneous, articular [CINCA] syndrome). These rare disorders are associated with
heterozygous mutations in the NLRP3 (CIAS1) gene, which encodes the protein
NALP3 or cryopyrin, and inflammation driven by excessive production of the
cytokine interleukin-1beta (IL-1beta). Amyloidosis is a serious complication
with 25% of MWS patients developing amyloidosis, with occasional fatal
consequences, whilst up to 20% of CINCA/NOMID patients die from various
complications, before reaching the early adulthood. In some CINCA/NOMID adult
survivors amyloidosis can also occur. Prior to the discovery of the CIAS1 gene
mutations and the advent of IL-1 targeted therapy, treatment was aimed at
suppressing inflammation, with limited success. The selective blockade of
IL-1beta, with anakinra (IL-1 receptor antagonist), not only provided supportive
evidence for the role of IL-1beta in CAPS, but also demonstrated the efficacy of
targeting IL-1beta for treatment of these conditions. In February, 2008, 'Orphan
Drug' approval from the Food and Drug Administration (FDA) for rilonacept (IL-1
Trap/Arcalyst(), Regeneron Pharmaceuticals, Inc) was given for the treatment of
two CAPS disorders, FCAS and MWS in adults and children 12 years and older,
making rilonacept the first therapy approved for the treatment of CAPS. Cryopyrin-associated periodic syndromes (CAPS) are a subgroup of the hereditary
periodic fever syndromes, which are rare autoinflammatory and inherited
disorders, characterized by recurrent inflammation and varying degrees of
severity. CAPS are thought to be driven by excessive production of
interleukin-1β (IL-1β), through over-activation of the inflammasome by gain of
function mutations in the gene encoding cryopyrin (NLRP3). This conclusion is
supported by the remarkable efficacy of IL-1β blockade in these conditions.
Rilonacept (Arcalyst(TM); Regeneron) is the first us Food and Drug
Administration-approved treatment for familial cold autoinflammatory syndrome
and Muckle-Wells syndrome and the first in a new line of drugs designed for
longer-acting IL-1 blockade. Rilonacept has been associated with a decrease in
disease activity, high-sensitivity C-reactive protein (hsCRP) and serum amyloid
A (SAA) in the treatment of CAPS. The clinical safety and efficacy of rilonacept
in CAPS and non-CAPS populations will be summarized in this review. Rilonacept
is also beneficial for patients who tolerate injections poorly, due to an
extended half-life over the unapproved CAPS treatment, anakinra, requiring
weekly rather than daily self-administration. Other autoinflammatory disorders
may also benefit from rilonacept treatment, with clinical trials in progress for
systemic onset juvenile idiopathic arthritis, gout and familial mediterranean
fever. |
What is ChIPpeakAnno? | ChIPpeakAnno is a Bioconductor package within the statistical programming environment R that facilitates batch annotation of enriched peaks identified from ChIP-seq, ChIP-chip, cap analysis of gene expression (CAGE) or any experiments resulting in a large number of enriched genomic regions. | BACKGROUND: Chromatin immunoprecipitation (ChIP) followed by high-throughput
sequencing (ChIP-seq) or ChIP followed by genome tiling array analysis
(ChIP-chip) have become standard technologies for genome-wide identification of
DNA-binding protein target sites. A number of algorithms have been developed in
parallel that allow identification of binding sites from ChIP-seq or ChIP-chip
datasets and subsequent visualization in the University of California Santa Cruz
(UCSC) Genome Browser as custom annotation tracks. However, summarizing these
tracks can be a daunting task, particularly if there are a large number of
binding sites or the binding sites are distributed widely across the genome.
RESULTS: We have developed ChIPpeakAnno as a Bioconductor package within the
statistical programming environment R to facilitate batch annotation of enriched
peaks identified from ChIP-seq, ChIP-chip, cap analysis of gene expression
(CAGE) or any experiments resulting in a large number of enriched genomic
regions. The binding sites annotated with ChIPpeakAnno can be viewed easily as a
table, a pie chart or plotted in histogram form, i.e., the distribution of
distances to the nearest genes for each set of peaks. In addition, we have
implemented functionalities for determining the significance of overlap between
replicates or binding sites among transcription factors within a complex, and
for drawing Venn diagrams to visualize the extent of the overlap between
replicates. Furthermore, the package includes functionalities to retrieve
sequences flanking putative binding sites for PCR amplification, cloning, or
motif discovery, and to identify Gene Ontology (GO) terms associated with
adjacent genes.
CONCLUSIONS: ChIPpeakAnno enables batch annotation of the binding sites
identified from ChIP-seq, ChIP-chip, CAGE or any technology that results in a
large number of enriched genomic regions within the statistical programming
environment R. Allowing users to pass their own annotation data such as a
different Chromatin immunoprecipitation (ChIP) preparation and a dataset from
literature, or existing annotation packages, such as GenomicFeatures and
BSgenome, provides flexibility. Tight integration to the biomaRt package enables
up-to-date annotation retrieval from the BioMart database. |
Signaling of which pathways is inhibited by Dupilumab? | Dupilumab, a fully human anti-interleukin-4 receptor α monoclonal antibody, inhibits interleukin-4 and interleukin-13 signalling. It is used for treatment of atopic or allergic diseases. | PURPOSE OF REVIEW: A small proportion of patients with asthma have severe
disease characterized by persistent airflow obstruction, airway
hyperresponsiveness and eosinophilic airway inflammation. This review focuses on
the clinical efficacy of inhibiting T helper 2-cytokine-mediated inflammatory
responses using monoclonal antibodies directed against immunoglobulin E (IgE),
interleukin (IL)-5, and IL-4/IL-13 in patients with severe refractory asthma.
RECENT FINDINGS: The heterogeneity of airway inflammation in severe asthma has
led to the recognition of multiple pathophysiologically distinct severe asthma
endotypes. Biomarkers are being developed and evaluated to identify these
endotypes and to guide the use of specific biologics in the appropriate patients
who remain uncontrolled on high doses of inhaled corticosteroids and long-acting
bronchodilators or oral corticosteroids. Examples include the efficacy of
omalizumab in patients with severe refractory atopic asthma characterized by
raised serum total IgE, mepolizumab, reslizumab, and benralizumab in patients
with recurrent eosinophilic exacerbations characterized by blood and sputum
eosinophilia despite high doses of corticosteroids, and lebrikizumab,
pitrakinra, dupilumab, and tralokinumab that target the IL-4/IL-13 signalling
pathways in patients with eosinophilic asthma or raised serum periostin.
SUMMARY: In severe refractory asthma, both an understanding of the underlying
pathophysiologic mechanisms driving airway inflammation and the identification
of appropriate biomarkers in individual patients are critical in guiding the use
of biologics and monoclonal antibodies that target the specific pathological
processes. Simultaneously with the steady progress towards a better knowledge of the
pathobiology of asthma, the potential usefulness of anticytokine therapies is
emerging as one of the key concepts in the newly developing treatments of this
widespread airway disease. In particular, given the key role played by
interleukin (IL)-4 and IL-13 in the pathophysiology of the most typical aspects
of asthma, such as chronic airway inflammation, tissue remodeling, and bronchial
hyperresponsiveness, these pleiotropic cytokines are now considered as suitable
therapeutic targets. Among the recently developed antiasthma biologic drugs, the
monoclonal antibody dupilumab is very promising because of its ability to
inhibit the biological effects of both IL-4 and IL-13. Indeed, dupilumab
prevents IL-4/13 interactions with the α-subunit of the IL-4 receptor complex. A
recent trial showed that in patients with difficult-to-control asthma, dupilumab
can markedly decrease asthma exacerbations and improve respiratory symptoms and
lung function; these effects were paralleled by significant reductions in
T-helper 2-associated inflammatory biomarkers. However, further larger and
longer trials are required to extend and validate these preliminary results, and
also to carefully study the safety and tolerability profile of dupilumab. BACKGROUND: Severe atopic dermatitis (AD) has a high unmet need for effective
and safe therapeutics. In early-phase trials, dupilumab, a fully human mAb
targeting IL-4 receptor α, markedly improved disease activity, but the effect of
IL-4/IL-13 blockade on AD at the molecular level has not been characterized.
OBJECTIVES: We sought to evaluate dupilumab modulation of the AD molecular
signature.
METHODS: We performed transcriptomic analyses of pretreatment and posttreatment
skin biopsy specimens from patients with moderate-to-severe AD treated weekly
with 150 or 300 mg of dupilumab or placebo.
RESULTS: Exacerbation of the AD transcriptome was observed in placebo-treated
patients. Dupilumab improved the AD signature in a dose-dependent manner.
Expression of genes upregulated in AD lesions decreased in patients treated with
dupilumab by 26% (95% CI, 21% to 32%) and 65% (95% CI, 60% to 71%) for treatment
with 150 and 300 mg, respectively. Genes downregulated in AD lesions increased
by 21% (95% CI, 16% to 27%) and 32% (95% CI, 26% to 37%) with dupilumab (150 and
300 mg, respectively). The molecular changes paralleled improvements in clinical
scores. A dupilumab treatment signature of 821 probes (>2-fold change, P < .05)
significantly modulated in the 300-mg dupilumab group at week 4 compared with
baseline was identified in this sample set. Significant (P < .05) decreases in
mRNA expression of genes related to hyperplasia (K16 and MKI67), T cells, and
dendritic cells (CD1b and CD1c) and potent inhibition of TH2-associated
chemokines (CCL17, CCL18, CCL22, and CCL26) were noted without significant
modulation of TH1-associated genes (IFNG).
CONCLUSIONS: This is the first report showing rapid improvement of the AD
molecular signature with targeted anti-IL-4 receptor α therapy. These data
suggest that IL-4 and IL-13 drive a complex, TH2-centered inflammatory axis in
patients with AD. Currently the only approved drug available for the systemic therapy of atopic
dermatitis is cyclosporine; however, based on current data from published
studies, azathioprine, methotrexate, and mycophenolate mofetil or mycophenolic
acid can be administered off-label. Some biologics on the market that have been
approved for other indications (ustekinumab, rituximab, tocilizumab) have been
successfully used in a few patients with atopic dermatitis. The world's first
prospective controlled studies with the biologic human anti-IL4R antibody
dupilumab for the indication "atopic dermatitis" were published in 2014. These
motivated (1) to extend the studies to dupilumab and (2) to clinically test
antagonization of other target molecules of TH2 polarized, atopic inflammation,
e.g., IL-13, IL-31, IL-22, TSLP, and CRTH2. A number of clinical trials are
currently recruiting in this area and will provide interesting new insights for
future therapeutic approaches in atopic dermatitis. INTRODUCTION: Current treatment options for moderate-to-severe atopic dermatitis
(AD) are limited and have potentially dangerous side effects. Dupilumab is a
novel monoclonal antibody that was recently studied in adult patients with
moderate-to-severe AD. Dupilumab inhibits interleukin-4 (IL-4) and
interleukin-13 (IL-13) signaling and was previously found to be effective in
asthma. Considering that both AD and asthma are Th2 cell-mediated inflammatory
processes, it is reasonable to suspect that dupilumab would be beneficial in
AD.`
AREAS COVERED: This article is a review of the one major clinical trial that
assessed the efficacy of dupilumab in patients with AD. Its goal is to provide a
comparison to the current modalities for the treatment of AD and expert insight
regarding future studies.
EXPERT OPINION: The results of this study are a significant therapeutic
advancement. Dupilumab was shown to provide a mean percent change in Eczema Area
and Severity Index score of -74% ± 3.6, in addition to, statistically and
clinically significant reductions the severity, symptomatology, and morbidity
associated with AD. However, the small sample size makes it difficult to assess
the magnitude of this effect. As a result, dupilumab will likely be reserved for
cases of severe AD unresponsive to traditional modalities. Atopic dermatitis results when aberrant barrier function and immune activation
occur within the skin. Standard therapies for atopic dermatitis have fallen
short, prompting efforts to discover novel therapeutics for this disease. Of
these, dupilumab, a fully human monoclonal antibody that inhibits the actions of
both IL-4 and IL-13, has shown the greatest promise. Clinical trials of systemic
dupilumab in moderate-to-severe atopic dermatitis have demonstrated marked
improvement in patient symptoms, including pruritus and clinically visible
disease. Importantly, dupilumab treatment has been correlated with changes in
the molecular signature of diseased skin, with reduction of both inflammatory
and proliferative markers. Dupilumab recently received US FDA breakthrough
therapy designation for atopic dermatitis, with ongoing trials in both adult and
pediatric populations. Altogether, dupilumab has shed new light on the
pathomechanisms driving atopic dermatitis and is making unprecedented advances
towards highly effective control of this debilitating disease. Asthma is a heterogeneous inflammatory disease. Most patients respond to current
standard of care, i.e., bronchodilators, inhaled glucocorticosteroids and other
anti-inflammatory drugs, but in some adequate asthma control cannot be achieved
with standard treatments. These difficult-to-treat patients would be the target
population for new biological therapies. At present, omalizumab is the only
biological agent approved for the treatment of early-onset, severe IgE-dependent
asthma. It is safe, effective, and well tolerated. Also, discovery of asthma
subtypes suggests new treatments. Half of patients with severe asthma have
T-helper type 2 (Th-2) inflammation and they are expected to benefit from
monoclonal antibody-based treatments. The efficacy of the investigational
monoclonal antibody mepolizumab which targets IL-5 has been well documented in
late onset non-atopic asthma with persistent eosinophilic airway inflammation.
Anti-IL-4 and IL-13 agents (dupilumab, lebrikizumab, and tralokinumab) which
block different Th-2 inflammatory pathways and agents targeting the Th-17
inflammatory pathway in severe refractory asthma are under development. In
clinical trials, these drugs reduce disease activity and improve lung function,
asthma symptoms, and quality of life. However, studies on larger groups of
patients are needed to confirm their safety and efficacy. The newer and emerging treatments for atopic dermatitis (AD) focus on blockade
of inflammatory cytokines, especially those that derive from T helper cell type
2 (TH2) and are associated with a pathway of immunoglobulin E (IgE)
sensitization. Among the proinflammatory cytokines that have been identified as
promising therapeutic targets are chemoattractant receptor-homologous molecule
expressed on TH2 cells (CRTH2), IgE, thymic stromal lymphopoietin (TSLP), and
several monoclonal antibodies that block key cytokine pathways in the innate
immune response. Two agents that have been studied in phase III clinical trials
are the boronbased phosphodiesterase-4 (PDE-4) inhibitor, crisaborole, and
dupilumab, an antibody that inhibits the interleukin-4/ IL-13 receptor α chain.
Semin Cutan Med Surg 35(supp5):S92-S96. Collaborators: Nikolova-Pavlova E, Stoyanova B, Vlaeva T, Alavi A, Gauvreau G,
Henein S, Poulos E, Yang W, Lepage F, Wiseman M, Bissonnette R, Agner T,
Deleuran M, Jemec G, Skov L, Kingo K, Konno P, Pender K, Põder A, Vahlberg A,
Oksman R, Pasternack R, Remitz A, Bieber T, Dominicus R, Gerlach B, Kardorff B,
Toader AL, Kleinheinz A, Gellrich S, Kreutzer K, Leitz N, Offers M, Pauser S,
Radtke M, Roloff E, Rosenbach T, Schwarz B, Sell S, Simon JC, Staubach P, Weigel
US, Werfel T, Wohlrab J, Wollenberg A, Rothenberger C, Walter A, Yazdi A, Aihara
M, Hide M, Kataoka Y, Katoh N, Kawashima M, Kobayashi S, Mitsui H, Nakahara T,
Saeki H, Sueki H, Arai S, Ikeda M, Kabashima K, Kawachi Y, Kume A, Moriwaki S,
Natsuaki Y, Ogata F, Omi T, Seishima M, Sugaya M, Tsukamoto K, Tsuruta D, Urano
S, Watanabe D, Yoshioka A, Furukawa F, Katoh A, Ang CC, Aw DC, Tang M, Lee HY,
Orpinell FB, Hernández GC, De La Cueva P, Foraster CF, Iranzo P, Serra AJ, Luna
PL, Moya SM, Ramírez DM, Muñoz JP, Carazo JS, Soong W, Hull C, Johnson S, Bhatia
N, Limova M, Raikhel M, Sher L, Sofen H, Spector S, Tan R, Yamauchi P, Weber R,
Kimura S, Nelson C, Randhawa S, Rendon M, Trevino M, Ling M, Rice Z, Silverberg
J, Siri D, Fretzin S, Fowler JF, Boh E, Merola J, Murakawa G, Korenblat P,
Campbell J, Bagel J, Beck L, Hazan C, Kalb R, Smith C, Bardelas J, Gawchik S,
Schenkel E, Krause R, Allison D, Browning J, Davis S, Lee M, Duffin K, Fisher
CT, Pariser D, Gower RG, Adams S, Sapijaszko MJ, Wasel N, Albrecht L, Hong CH,
Gulliver W, Landells I, Adam D, Gooderham M, Lomaga M, Lynde C, Rosoph L, Raman
M, Robern M, Sapra S, Toth D, Poulin Y, Bagot M, Barbarot S, Grob JJ, Guillet G,
Lacour JP, Khemis A, Misery L, Staumont-Sallé D, Brüning H, Darsow U,
Ekanayake-Bohlig S, Herbst R, Hoffmann M, Homey B, Niesmann J, Pinter A, Radny
P, Reich K, Sattler G, Sebastian M, Thaçi D, Weidinger S, Wildfeuer T, Worm M,
Chan H, Chan J, Amerio P, Carlesimo M, Di Lernia V, Emilia R, Didona B, Fargnoli
M, Ferrucci SM, Naldi L, Papini M, Parodi A, Pellacani G, Peris K, Pimpinelli N,
Romanelli M, Talamonti M, Bylaite-Bucinskiene M, Cesiene J, Narbutas R,
Sidlauskiene RB, Kucinskiene V, Adamski Z, Bystrzanowska D, Dyczek A, Hofman T,
Leszniewska L, Nowicki R, Owczarek W, Slowinska M, Sobieszek-Kundro A, Weglowska
J, Zakrzewski M, Ahn HH, Ahn KJ, Chang SE, Choi GS, Kim MB, Kim KH, Lee KH, Park
YM, Park CW, Park GH, Nahm DH, Park YL, Roh J, Seo SJ, Ameen M, Ardern-Jones M,
Bewley A, Cooper H, Cork MJ, Guha-Niyogi B, Khan M, Marshall M, Foerster J,
Smith C, Appell M, Elewski B, Haynes S, Jazayeri SS, Crowley J, Dhawan S, Ellis
M, Kim S, Meltzer S, Mitchell J, Pearlman D, Moss J, Ehrlich A, Forman S,
Kuttner B, Penate F, Vaca C, Hamilton T, Paull W, Weisman J, Glazer S, Mehlis S,
Guenthner S, Lockshin B, Kimball A, Rosmarin D, Pickett-Baisden T, Halverson P,
Kaiser H, Martin A, Stone M, Davis K, Mirkil V, Nossa R, Bretton E, Alexis A,
Guttman-Yassky E, Peredo M, Weinberg J, Fleischer A, George R, Lugo-Somolinos A,
Nasir A, Hussain I, Blauvelt A, Simpson E, Kalafer M, Hampton M, Humeniuk JM,
Rupp N, Carrasco D, MacGillivray B, Moore A, Teller C, Tyring S, Harris D,
Jenkin P. |
Does the TOP2B/TOP2A expression ratio affect the response to AML chemotherapy? | High TOP2B/TOP2A expression ratio at diagnosis correlates with favourable outcome for standard chemotherapy in acute myeloid leukaemia Genes with distinct expression profiles such as TOP2B/TOP2A expression ratio at diagnosis can be employed for outcome prediction after the treatment with standard regimens in AML patients with M2 subtype. | BACKGROUND: Cytosine arabinoside-based chemotherapy coupled with anthracycline
is currently the first-line treatment for acute myeloid leukaemia (AML), but
diverse responses to the regimen constitute obstacles to successful treatment.
Therefore, outcome prediction to chemotherapy at diagnosis is believed to be a
critical consideration.
METHODS: The mRNA expression of 12 genes closely involved in the actions of
cytosine arabinoside and anthracycline was evaluated by real-time reverse
transcriptase PCR (RT-PCR), in 54 diagnostic bone marrow specimens of M2-subtype
AML.
RESULTS: Low expression levels of ribonucleotide reductase M2 (RRM2) and high
expression levels of topoisomerase 2 beta (TOP2B) were correlated with longer
survival in a univariate analysis. Another interesting finding is that high
ratios of TOP2B/RRM2 and TOP2B/TOP2 alpha (TOP2A) in a combined analysis were
also shown to have a prognostic impact for longer survival with improved
accuracy. Among the four markers, when adjusted for the influence of other
clinical factors in multivariate analysis, the TOP2B/TOP2A ratio was
significantly correlated with treatment outcomes; patients with high ratios
trended toward longer disease-free survival (HR, 0.24; P=0.002) and overall
survival (HR, 0.29; P=0.005).
CONCLUSION: Genes with distinct expression profiles such as TOP2B/TOP2A
expression ratio at diagnosis can be employed for outcome prediction after the
treatment with standard regimens in AML patients with M2 subtype. |
List the three main structures of the cytoskeleton. | Fibrillar polymers-actin filaments, microtubules, and intermediate filaments-are major constituents of the cytoskeleton. | The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm
playing critical roles in cell motility, shape generation, and mechanical
properties of a cell. Fibrillar polymers-actin filaments, microtubules, and
intermediate filaments-are major constituents of the cytoskeleton, which
constantly change their organization during cellular activities. The actin
cytoskeleton is especially polymorphic, as actin filaments can form multiple
higher order assemblies performing different functions. Structural information
about cytoskeleton organization is critical for understanding its functions and
mechanisms underlying various forms of cellular activity. Because of the
ometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a
key tool to determine the structure of the cytoskeleton. This article describes
application of rotary shadowing (or metal replica) EM for visualization of the
cytoskeleton. The procedure is applicable to thin cultured cells growing on
glass coverslips and consists of detergent extraction of cells to expose their
cytoskeleton, chemical fixation to provide stability, ethanol dehydration and
critical point drying to preserve three-dimensionality, rotary shadowing with
platinum to create contrast, and carbon coating to stabilize replicas. This
technique provides easily interpretable three-dimensional images, in which
individual cytoskeletal fibers are clearly resolved, and individual proteins can
be identified by immunogold labeling. More importantly, replica EM is easily
compatible with live cell imaging, so that one can correlate the dynamics of a
cell or its components, e.g., expressed fluorescent proteins, with high
resolution structural organization of the cytoskeleton in the same cell. |
What is the genus for the common European honey bee? | The genus and species of the European honey bee is Apis mellifera. | Nosema ceranae is an emerging microsporidian parasite of European honey bees,
Apis mellifera, but its distribution is not well known. Six Nosema-positive
samples (determined from light microscopy of spores) of adult worker bees from
Canada (two each from Nova Scotia, New Brunswick, and Prince Edward Island) and
two from USA (Minnesota) were tested to determine Nosema species using
previously-developed PCR primers of the 16S rRNA gene. We detected for the first
time N. ceranae in Canada and central USA. One haplotype of N. ceranae was
identified; its virulence may differ from that of other haplotypes. Mites in the genus Tropilaelaps (Acari: Laelapidae) are ectoparasites of the
brood of honey bees (Apis spp.). Different Tropilaelaps subspecies were
originally described from Apis dorsata, but a host switch occurred to the
Western honey bee, Apis mellifera, for which infestations can rapidly lead to
colony death. Tropilaelaps is hence considered more dangerous to A. mellifera
than the parasitic mite Varroa destructor. Honey bees are also infected by many
different viruses, some of them associated with and vectored by V. destructor.
In recent years, deformed wing virus (DWV) has become the most prevalent virus
infection in honey bees associated with V. destructor. DWV is distributed
world-wide, and found wherever the Varroa mite is found, although low levels of
the virus can also be found in Varroa free colonies. The Varroa mite transmits
viral particles when feeding on the haemolymph of pupae or adult bees. Both the
Tropilaelaps mite and the Varroa mite feed on honey bee brood, but no
observations of DWV in Tropilaelaps have so far been reported. In this study,
quantitative real-time RT-PCR was used to show the presence of DWV in infested
brood and Tropilaelaps mercedesae mites collected in China, and to demonstrate a
close quantitative association between mite-infested pupae of A. mellifera and
DWV infections. Phylogenetic analysis of the DWV sequences recovered from
matching pupae and mites revealed considerable DWV sequence heterogeneity and
polymorphism. These polymorphisms appeared to be associated with the individual
brood cell, rather than with a particular host. Invasion of alien species has been shown to cause detrimental effects on
habitats of native species. Insect pollinators represent such examples; the
introduction of commercial bumble bee species for crop pollination has resulted
in competition for an ecological niche with native species, genetic disturbance
caused by mating with native species, and pathogen spillover to native species.
The European honey bee, Apis mellifera, was first introduced into Japan for
apiculture in 1877, and queen bees have been imported from several countries for
many years. However, its effects on Japanese native honey bee, Apis cerana
japonica, have never been addressed. We thus conducted the survey of honey bee
viruses and Acarapis mites using both A. mellifera and A. c. japonica colonies
to examine their infestation in native and non-native honey bee species in
Japan. Honey bee viruses, Deformed wing virus (DWV), Black queen cell virus
(BQCV), Israeli acute paralysis virus (IAPV), and Sacbrood virus (SBV), were
found in both A. mellifera and A. c. japonica colonies; however, the infection
frequency of viruses in A. c. japonica was lower than that in A. mellifera
colonies. Based on the phylogenies of DWV, BQCV, and SBV isolates from A.
mellifera and A. c. japonica, DWV and BQCV may infect both honey bee species;
meanwhile, SBV has a clear species barrier. For the first time in Japan,
tracheal mite (Acarapis woodi) was specifically found in the dead honey bees
from collapsing A. c. japonica colonies. This paper thus provides further
evidence that tracheal-mite-infested honey bee colonies can die during cool
winters with no other disease present. These results demonstrate the infestation
of native honey bees by parasite and pathogens of non-native honey bees that are
traded globally. BACKGROUND: Aethina tumida is a serious pest of the European honey bee (Apis
mellifera) in North America and Australia. Here we investigate whether Laccase
2, the phenoloxidase gene essential for cuticle sclerotisation and pigmentation
in many insects, and vacuolar-ATPase V-type subunit A, vital for the generation
of proton gradients used to drive a range of transport processes, could be
potential targets for RNAi-mediated control of A. tumida.
RESULTS: Injection of V-ATPase subunit A (5 ng) and Laccase 2 (12.5 ng) dsRNAs
resulted in 100% larval mortality, and qPCR confirmed significant decreases and
enhanced suppression of transcript levels over time. Oral delivery of V-ATPase
subunit A dsRNA in solutions resulted in 50% mortality; however, gene
suppression could not be verified. We suggest that the inconsistent RNAi effect
was a consequence of dsRNA degradation within the gut owing to the presence of
extracellular nucleases. Target specificity was confirmed by a lack of effect on
survival or gene expression in honey bees injected with A. tumida dsRNAs.
CONCLUSION: This is the first study to show evidence for systemic RNAi in A.
tumida in response to injected dsRNA, but further research is required to
develop methods to induce RNAi effects via ingestion. © 2016 Crown copyright.
Pest Management Science © 2016 Society of Chemical Industry. Ecological risk assessment of plant protection products (PPPs) requires an
understanding of both the toxicity and the extent of exposure to assess risks
for a range of taxa of ecological importance including target and non-target
species. Non-target species such as honey bees (Apis mellifera), solitary bees
and bumble bees are of utmost importance because of their vital ecological
services as pollinators of wild plants and crops. To improve risk assessment of
PPPs in bee species, computational models predicting the acute and chronic
toxicity of a range of PPPs and contamits can play a major role in providing
structural and physico-chemical properties for the prioritisation of compounds
of concern and future risk assessments. Over the last three decades, scientific
advisory bodies and the research community have developed toxicological
databases and quantitative structure-activity relationship (QSAR) models that
are proving invaluable to predict toxicity using historical data and reduce
animal testing. This paper describes the development and validation of a
k-Nearest Neighbor (k-NN) model using in-house software for the prediction of
acute contact toxicity of pesticides on honey bees. Acute contact toxicity data
were collected from different sources for 256 pesticides, which were divided
into training and test sets. The k-NN models were validated with good
prediction, with an accuracy of 70% for all compounds and of 65% for highly
toxic compounds, suggesting that they might reliably predict the toxicity of
structurally diverse pesticides and could be used to screen and prioritise new
pesticides. |
Where is the TAZ (G4.5) is located in humans? | TAZ gene (G4.5) is located on Xq28 in humans. | Barth syndrome is an X-linked cardiomyopathy with neutropenia and
3-methylglutaconic aciduria. Recently, mutations in the G4.5 gene, located in
Xq28, have been described in four probands with Barth syndrome. We have now
evaluated 14 Barth syndrome pedigrees for mutations in G4.5 and have identified
unique mutations in all, including four splice-site mutations, three deletions,
one insertion, five missense mutations, and one nonsense mutation. Nine of the
14 mutations are predicted to significantly disrupt the protein products of
G4.5. The occurrence of missense mutations in exons 3 and 8 suggests that these
exons encode essential portions of the G4. 5 proteins, whose functions remain
unknown. We found no correlation between the location or type of mutation and
any of the clinical or laboratory abnormalities of Barth syndrome, which
suggests that additional factors modify the expression of the Barth phenotype.
The characterization of mutations of the G4.5 gene will be useful for carrier
detection, genetic counseling, and the identification of patients with Barth
syndrome who do not manifest all of the cardinal features of this disorder. X-linked cardioskeletal myopathy, neutropenia and abnormal mitochondria (MIM
302060) (synonyms: Barth syndrome, 3-methylglutaconic acid-uria type II,
endocardial fibroelastosis type 2) has been reported in patients and families
from Europe, North America and Australia. Previous studies characterized the
main components of the disease: dilated cardiomyopathy, skeletal myopathy,
neutropenia, 3-methylglutaconic aciduria and diminished statural growth.
Respiratory chain impairments have been found in several studies, without
pinpointing a single enzyme complex. 3-Methylglutaconic aciduria is shared with
several other disorders that affect the respiratory chain. Previous studies
excluded a block in the major pathway of leucine catabolism. We performed
leucine loading, accompanied by fasting, in patients and observed a significant
rise of 3-methylglutaconic acid and 3-methylglutaric acid. Taken together with
the absence of an enzymatic block in the major leucine catabolic route, the
possibility remains that the increased basal excretion of 3-methylglutaconic
acid and other products of branched-chain amino acids is the result of overload
of this pathway or--more likely--mitochondrial leakage. Linkage studies have
localized the gene to the Xq28 region. The associated tafazzin gene (TAZ), has
been fully characterized recently, and mutations located in conserved regions
have been reported. Carrier detection and prenatal diagnosis have now become
possible through mutation analysis. Sequence homology of the TAZ gene to a
highly conserved superclass of acyltransferases (Neuwald's hypothesis) predicts
a glycerophospholipid as the missing end product. This points to the (lipid)
structure of the inner mitochondrial membrane as a promising new area of
research. Mutation analysis of the TAZ ( G4.5) gene was performed on a patient with Barth
syndrome. The reverse transcription/polymerase chain reaction procedure showed
aberrant splicing and elongation of exon 3 because of the insertion of 106 bases
(IVS3+1 to +106) between exons 3 and 4. The genomic DNA revealed an intronic
mutation four bases downstream from the new cleavage site (IVS3+110G-->A). The
IVS3+110G-->A mutation created a novel 5' splice site that showed GC but not GT,
and the additional splice site was used preferentially over the upstream
authentic slice site. This is a new type of splicing mutation responsible for a
human genetic disease. First described in 1983, Barth syndrome (BTHS) is widely regarded as a rare
X-linked genetic disease characterised by cardiomyopathy (CM), skeletal
myopathy, growth delay, neutropenia and increased urinary excretion of
3-methylglutaconic acid (3-MGCA). Fewer than 200 living males are known
worldwide, but evidence is accumulating that the disorder is substantially
under-diagnosed. Clinical features include variable combinations of the
following wide spectrum: dilated cardiomyopathy (DCM), hypertrophic
cardiomyopathy (HCM), endocardial fibroelastosis (EFE), left ventricular
non-compaction (LVNC), ventricular arrhythmia, sudden cardiac death, prolonged
QTc interval, delayed motor milestones, proximal myopathy, lethargy and fatigue,
neutropenia (absent to severe; persistent, intermittent or perfectly cyclical),
compensatory monocytosis, recurrent bacterial infection, hypoglycaemia, lactic
acidosis, growth and pubertal delay, feeding problems, failure to thrive,
episodic diarrhoea, characteristic facies, and X-linked family history.
Historically regarded as a cardiac disease, BTHS is now considered a
multi-system disorder which may be first seen by many different specialists or
generalists. Phenotypic breadth and variability present a major challenge to the
diagnostician: some children with BTHS have never been neutropenic, whereas
others lack increased 3-MGCA and a minority has occult or absent CM.
Furthermore, BTHS was first described in 2010 as an unrecognised cause of fetal
death. Disabling mutations or deletions of the tafazzin (TAZ) gene, located at
Xq28, cause the disorder by reducing remodeling of cardiolipin, a principal
phospholipid of the inner mitochondrial membrane. A definitive biochemical test,
based on detecting abnormal ratios of different cardiolipin species, was first
described in 2008. Key areas of differential diagnosis include metabolic and
viral cardiomyopathies, mitochondrial diseases, and many causes of neutropenia
and recurrent male miscarriage and stillbirth. Cardiolipin testing and TAZ
sequencing now provide relatively rapid diagnostic testing, both prospectively
and retrospectively, from a range of fresh or stored tissues, blood or neonatal
bloodspots. TAZ sequencing also allows female carrier detection and antenatal
screening. Management of BTHS includes medical therapy of CM, cardiac
transplantation (in 14% of patients), antibiotic prophylaxis and granulocyte
colony-stimulating factor (G-CSF) therapy. Multidisciplinary teams/clinics are
essential for minimising hospital attendances and allowing many more individuals
with BTHS to live into adulthood. OBJECTIVE: Barth syndrome is an X-linked recessive disorder characterized by
dilated cardiomyopathy, neutropenia, 3-methylglutaconic aciduria, abnormal
mitochondria, variably expressed skeletal myopathy, and growth delay. The
disorder is caused by mutations in the tafazzin (TAZ/G4.5) gene located on Xq28.
We report a novel exonic splicing mutation in the TAZ gene in a patient with
atypical Barth syndrome.
PATIENT & METHODS: The 4-month-old proband presented with respiratory distress,
neutropenia, and dilated cardiomyopathy with reduced ejection fraction of 10%.
No 3-methylglutaconic aciduria was detected on repeated urine organic acid
analyses. Family history indicated that his maternal uncle died of endocardial
fibroelastosis and dilated cardiomyopathy at 26 months. TAZ DNA sequencing, mRNA
analysis, and cardiolipin analysis were performed.
RESULTS: A novel nucleotide substitution c.553A>G in exon 7 of the TAZ gene was
identified in the proband, predicting an amino acid substitution p.Met185Val.
However, this mutation created a new splice donor signal within exon 7 causing
mis-splicing of the message, producing two messages that only differ in the
presence/absence of exon 5; these retain intron 6 and have only 11 bases of exon
7. Cardiolipin analysis confirmed the loss of tafazzin activity. The proband's
mother, maternal aunt, and grandmother carry the same mutation.
CONCLUSIONS: The identification of a TAZ gene mutation, mRNA analysis, and
monolysocardiolipin/cardiolipin ratio determination were important for the
diagnosis and genetic counseling in this family with atypical Barth syndrome
that was not found to be associated with 3-methylglutaconic aciduria. Tafazzin (EC 2.3.1.23) is a Phospholipid Transacylase involved in Cardiolipin
remodeling on mitochondrial membrane and coded by TAZ gene (Cytogenetic
Location: Xq28) in human. Its mutations cause Barth syndrome (MIM ID:
#302060)/3-Methyl Glutaconyl Aciduria Type II, an inborn error of metabolism
often leading to foetal or infantile fatality. Nevertheless, some mis-sense
mutations result in mild clinical symptoms. To evaluate the rationale of mild
symptoms and for an insight of Tafazzin active site, sequence based and
structure based ramifications of wild and mutant Tafazzins were compared
in-silico. Sequence based domain predictions, surface accessibilities on
substitution & conserved catalytic sites with statistical drifts, as well as
thermal stability changes for the mutations and the interaction analysis of
Tafazzin were performed. Crystal structure of Tafazzin is not yet resolved
experimentally, therefore 3D coordinates of Tafazzin and its mutants were
spawned through homology modeling. Energetically minimized and structurally
validated models were used for comparative docking simulations. We analyzed
active site geometry of the models in addition to calculating overall substrate
binding efficiencies for each of the enzyme-ligand complex deduced from binding
energies instead of comparing only the docking scores. Also, individual binding
energies of catalytic residues on conserved HX4D motif of Acyltransferase
superfamily present in Tafazzins were estimated. This work elucidates the basis
of mild symptoms in patients with mis-sense mutations, identifies the most
pathogenic mutant among others in the study and also divulges the critical role
of HX4D domain towards successful transacylation by Taffazin. The in-silico
observations are in complete agreement with clinical findings reported for the
patients with mutations. |
What do nerve-associated peripheral glial progenitors give rise to? | Nerve-associated peripheral glial progenitors give rise to parasympathetic neurons. The parasympathetic system in mice--including trunk ganglia and the cranial ciliary, pterygopalatine, lingual, submandibular, and otic ganglia--arise from glial cells in nerves, not neural crest cells. The parasympathetic fate is induced in nerve-associated Schwann cell precursors at distal peripheral sites. | Author information:
(1)Unit of Molecular Neurobiology, Department of Medical Biochemistry and
Biophysics, Karolinska Institutet, Stockholm, Sweden. A.V. Zhirmunsky Institute
of Marine Biology of the Far Eastern Branch of the Russian Academy of Sciences,
Vladivostok, Russia.
(2)Unit of Molecular Neurobiology, Department of Medical Biochemistry and
Biophysics, Karolinska Institutet, Stockholm, Sweden.
(3)Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden.
(4)Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
(5)Division of Molecular Neurobiology, Medical Research Council (MRC) National
Institute for Medical Research, London, UK.
(6)Department of Neuroscience, The Max Delbrück Center for Molecular Medicine,
Berlin-Buch, Germany.
(7)Unit of Molecular Neurobiology, Department of Medical Biochemistry and
Biophysics, Karolinska Institutet, Stockholm, Sweden. [email protected]
[email protected].
(8)Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm,
Sweden. [email protected] [email protected]. |
How many topological associated domains are contained in the human Hox cluster? | transcriptional activation is associated with a dynamic bi-modal 3d organization, whereby the genes switch autonomously from an inactive to an active compartment. | Hox genes are essential regulators of embryonic development. Their step-wise
transcriptional activation follows their genomic topology and the various states
of activation are subsequently memorized into domains of progressively
overlapping gene products. We have analyzed the 3D chromatin organization of Hox
clusters during their early activation in vivo, using high-resolution circular
chromosome conformation capture. Initially, Hox clusters are organized as single
chromatin compartments containing all genes and bivalent chromatin marks.
Transcriptional activation is associated with a dynamic bi-modal 3D
organization, whereby the genes switch autonomously from an inactive to an
active compartment. These local 3D dynamics occur within a framework of
constitutive interactions within the surrounding Topological Associated Domains,
indicating that this regulation process is mostly cluster intrinsic. The
step-wise progression in time is fixed at various body levels and thus can
account for the chromatin architectures previously described at a later stage
for different anterior to posterior levels.DOI:
http://dx.doi.org/10.7554/eLife.02557.001. |
Is Lennox-Gastaut Syndrome usually diagnosed in older adults? | lennox-gastaut syndrome (lgs) is a severe pediatric epilepsy syndrome characterized by mixed seizures, cognitive decline, and generalized slow (<3 hz) spike wave discharges on electroencephalography. | Clinical course and results of therapy were analysed in the group of 92
children, aged between 3 and 9 years, with diagnosed Lennox-Gastaut syndrome.
The obtained results of an analysis have shown that Lennox-Gastaut syndrome
origin is not clear--causative factor can not be established in 1/3 of patients
whereas in 1/2 of them abnormal course of pregcy and perinatal period is
noted. Together with seizures of various origin, other focal neurological
symptoms, mental retardation and abnormalities in CT scans of the brain are
frequently seen in patients with Lennox-Gastaut syndrome. Clinical course,
prognosis and results of therapy are largely dependent on the degree of mental
development before the onset of epileptic seizures, course of pregcy and
perinatal period, and the time of therapy. Children with Lennox-Gastaut syndrome
require relative polytherapy in which valproic acid derivatives are
predominating together with benzodiazepines, and temporary corticosteroids. An
improvement was achieved in about 30% of the treated children. Prognosis in the
remaining 70% of children is rather poor. Irregular administration of drugs,
frequent changes of anti-epileptic agents, too low doses and abnormal
environmental effects (abnormal parental attitudes) affect the results of
therapy. An emphasis is on the poor prognosis in Lennox-Gastaut syndrome
proceeded with West syndrome. BACKGROUND: The Lennox-Gastaut syndrome is an age-specific disorder,
characterised by epileptic seizures, a characteristic electroencephalogram
(EEG), psychomotor delay and behaviour disorders. It occurs more frequently in
males and onset is usually before the age of eight, with a peak between three
and five years. Late cases occurring in adolescence and early adulthood have
rarely been reported. Language is frequently affected, with both slowness in
ideation and expression in addition to difficulties of motor dysfunction. Severe
behavioural disorders (for example hyperactivity, aggressiveness and autistic
tendencies) and personality disorders are nearly always present. There is also a
tendency for psychosis to develop with time. The long-term prognosis is poor;
although the epilepsy often improves, complete seizure freedom is rare and
conversely the mental and psychiatric disorders tend to worsen with time.
OBJECTIVES: To compare the effects of pharmaceutical therapies used to treat
Lennox-Gastaut syndrome in terms of control of seizures and adverse effects.
Many people who suffer from this syndrome will already be receiving other
antiepileptic medications at the time of their entry into a trial. However, for
the purpose of this review we will only consider the effect of the single
therapeutic agent being trialed (often as add-on therapy).
SEARCH STRATEGY: We searched the Cochrane Epilepsy Group's Specialized Register
(February 2009), the Cochrane Central Register of Controlled Trials (CENTRAL)
(The Cochrane Library Issue 1, 2009), and MEDLINE (1950 to January 2009). We
also searched EMBASE (1980 to March 2003). We imposed no language restrictions.
We searched the ISRCTN register for ongoing trials and in addition, we contacted
pharmaceutical companies and colleagues in the field to seek any unpublished or
ongoing studies.
SELECTION CRITERIA: All randomised controlled trials (RCTs) of the
administration of drug therapy to patients with Lennox-Gastaut syndrome.
DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data.
Analysis included assessing study quality, as well as statistical analysis of
the effects on overall seizure rates and effects on specific seizure types (e.g.
drop attacks), adverse effects and mortality.
MAIN RESULTS: We found seven RCTs, but were unable to perform any meta-analysis,
because each trial looked at different populations, different therapies and
considered different outcomes.
AUTHORS' CONCLUSIONS: The optimum treatment for Lennox-Gastaut syndrome remains
uncertain and no study to date has shown any one drug to be highly efficacious;
rufinamide, lamotrigine, topiramate and felbamate may be helpful as add-on
therapy. Until further research has been undertaken, clinicians will need to
continue to consider each patient individually, taking into account the
potential benefit of each therapy weighed against the risk of adverse effects. Lennox-Gastaut syndrome is a relatively rare epilepsy syndrome that usually
begins in early-mid childhood and is characterized by multiple seizure types,
particularly generalized seizures, which are often resistant to antiepileptic
drug medication. Rufinamide is a new antiepileptic drug approved as adjunctive
therapy to treat seizures in Lennox-Gastaut syndrome in those 4 years of age and
older. In this article, the putative mechanism of action is described, along
with data relating to its pharmacokinetics and metabolism. Key findings from
clinical trials are presented and discussed. Adverse effects are summarized and
compared with those encountered with competitor antiepileptic drugs. Finally,
the role of rufinamide in the holistic management of subjects with
Lennox-Gastaut syndrome is considered. The clinical symptoms associated with chromosome 15q duplication syndrome
manifest through a heterogeneous group of symptoms characterised by hypotonia,
delay in motor skills and language development, cognitive and learning
disabilities, autism spectrum disorder and refractory epilepsy. The late
development of Lennox-Gastaut syndrome in patients with 15q11q13 duplication is
a possibility that physicians should be aware of. We report the case of a
27-year-old man with a neurodevelopmental syndrome due to a 15q duplication,
with intellectual disability, psychiatric disturbances, and an epileptic
phenotype diagnosed as late-onset Lennox-Gastaut syndrome. There is scanty data regarding the efficacy and tolerability of the modified
Atkins diet in children with Lennox-Gastaut syndrome. This study was a
retrospective review of children with Lennox-Gastaut syndrome treated with the
modified Atkins diet from May 2009 and March 2011. The diet was initiated in
those children who persisted to have daily seizures despite the use of at least
3 appropriate antiepileptic drugs. Twenty-five children were started on a
modified Atkins diet, restricting carbohydrate intake to 10 g/d. After 3 months,
2 patients were seizure-free, and 10/25 children had >50% reduction in seizure
frequency. At 6 months, of 11 patients on the diet, 3 were seizure free and 8
had >50% reduction in seizure frequency. At 1 year, all 9 children on diet had
>50% reduction in seizure frequency. The side effects of the diet were mild. The
modified Atkins diet was found to be effective and well tolerated in children
with Lennox-Gastaut syndrome. Lennox-Gastaut syndrome (LGS) is a severe pediatric epilepsy syndrome
characterized by mixed seizures, cognitive decline, and generalized slow (<3 Hz)
spike wave discharges on electroencephalography. Atonic seizures result in
dangerous drop attacks with risks of injury and impairment of the quality of
life. The seizures are frequently resistant to multiple antiepileptic (AED)
drugs. Newer AEDs, such as rufinamide, are now available. When multiple AED
trials fail, non-pharmacological treatments such as the ketogenic diet, vagus
nerve stimulation, and epilepsy surgery, should be considered. The aim of this
review is to present an updated outline of LGS and the available treatments.
Although the prognosis for complete seizure control remains poor, the addition
of newer therapies provides an improved hope for some of these patients and
their families. Further long term randomized controlled trials are required to
compare different therapeutic interventions in terms of efficacy and
tolerability. OBJECTIVE: In patients with Lennox-Gastaut syndrome (LGS), recurrent epileptic
activity is thought to contribute to impaired cognition (epileptic
encephalopathy). Using concurrent electroencephalography-functional magnetic
resoce imaging (EEG-fMRI), we recently showed that epileptiform discharges in
LGS recruit large-scale networks that normally support key cognitive processes.
In LGS, given that epileptic activity engages cognitive networks, and cognition
is pervasively impaired, we hypothesized that cognitive network interactions in
LGS are persistently abnormal.
METHODS: We studied 15 LGS patients (mean age ± 1 standard deviation [SD] = 28.7
± 10.6 years) and 17 healthy controls (mean age ± 1 SD = 27.6 ± 6.6 years) using
task-free EEG-fMRI. Four networks of interest (default-mode, dorsal attention,
executive control, and anterior salience) were defined using group-level
independent components analysis (ICA). Functional connectivity within and
between networks was determined for each subject, and then LGS network
interactions were compared to network behavior in the control group. To test
whether group differences were present in periods without scalp-detectable
epileptiform discharges (i.e., persistent), we separately assessed
discharge-affected and discharge-unaffected epochs in six patients with
sufficient data for this analysis.
RESULTS: In LGS, cognitive networks showed (1) reduced within-network
integration, including weaker connectivity within the default-mode network, and
(2) impaired between-network segregation, including stronger connectivity
between the default-mode and dorsal attention networks. Abnormal interactions
were present during fMRI periods with and without discharges, indicating that
impaired network behavior may endure during periods without scalp-detectable
epileptic activity.
SIGNIFICANCE: In LGS, cognitive network interactions are persistently abnormal.
Given that cognition typically worsens with the onset of LGS, and may improve
after seizure control, our findings are consistent with the hypothesis that the
epileptic process in LGS may initiate and perhaps sustain abnormal network
behavior. We propose that epileptic encephalopathy may be a consequence of
persistently disrupted cognitive network interactions. |
Which treatment methods were compared in the EXCEL Trial? | EXCEL trial compared Everolimus Eluting Stent vs. Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization. | OBJECTIVES: The aim of this study is to verify the study hypothesis of the EXCEL
trial by comparing percutaneous coronary intervention (PCI) and coronary artery
bypass graft (CABG) in an EXCEL-like population of patients.
BACKGROUND: The upcoming EXCEL trial will test the hypothesis that left main
patients with SYNTAX score ≤ 32 experience similar rates of 3-year death,
myocardial infarction (MI), or cerebrovascular accidents (CVA) following
revascularization by PCI or CABG.
METHODS: We compared the 3-year rates of death/MI/CVA and death/MI/CVA/target
vessel revascularization (MACCE) in 556 patients with left main disease and
SYNTAX score ≤ 32 undergoing PCI (n = 285) or CABG (n = 271). To account for
confounders, outcome parameters underwent extensive statistical adjustment.
RESULTS: The unadjusted incidence of death/MI/CVA was similar between PCI and
CABG (12.7% vs. 8.4%, P = 0.892), while MACCE were higher in the PCI group
compared to the CABG group (27.0% vs. 11.8%, P < 0.001). After propensity score
matching, PCI was not associated with a significant increase in the rate of
death/MI/CVA (11.8% vs. 10.7%, P = 0.948), while MACCE were more frequently
noted among patients treated with PCI (28.8% vs. 14.1%, P = 0.002). Adjustment
by means of SYNTAX score and EUROSCORE, covariates with and without propensity
score, and propensity score alone did not change significantly these findings.
CONCLUSIONS: In an EXCEL-like cohort of patients with left main disease, there
seems to be a clinical equipoise between PCI and CABG in terms of death/MI/CVA.
However, even in patients with SYNTAX score ≤ 32, CABG is superior to PCI when
target vessel revascularization is included in the combined endpoint. Coronary artery bypass grafting (CABG) is the gold standard for the treatment of
left main disease, whereas percutaneous coronary intervention is a viable option
for patients who are candidates for revascularization but ineligible for CABG.
CABG is limited by extended hospital stay followed by rehabilitation and
mediocre long-term patency of saphenous vein grafts. Drug-eluting stents
decrease the restenosis rates compared with bare metal stents and provide
comparable clinical outcomes with those of CABG. Patients with isolated left
main disease limited to the ostium or midbody are most likely to have good
clinical outcomes with low restenosis and stent thrombosis rates. The results of
the ongoing EXCEL trial, which compares left main percutaneous coronary
intervention with drug-eluting stents and CABG, will provide insight regarding
the ideal revascularization strategy for these patients. The Evaluation of Xience Prime or Xience V versus Coronary Artery Bypass Surgery
for Effectiveness of Left Main Revascularization (EXCEL) trial is a multicenter,
ongoing trial conducted in patients with left main disease and SYNTAX score ≤ 32
to establish the presumptive advantage of percutaneous coronary intervention
(PCI) versus bypass surgery in patients with less complex coronary artery
disease than those enrolled in the Synergy between PCI with Taxus and Cardiac
Surgery (SYNTAX) trial. In this article, we aimed at critically discussing key
features and issues relevant to design and clinical interpretation of this new
contemporary trial of left main PCI. PURPOSE OF REVIEW: The aim of this article is to review the current
revascularization strategies in patients presenting with unprotected left main
coronary artery disease (LMCAD).
RECENT FINDINGS: Coronary artery bypass grafting (CABG) is the current standard
of treatment for patients with LMCAD. The development and refinement of
techniques increased the number of percutaneous coronary interventions (PCI) in
LMCAD patients.
SUMMARY: Although several observational studies show comparable results of CABG
and/or PCI in patients with LMCAD, there is currently no convincing randomized
evidence that either one of the two is associated with better long-term
survival. Recent meta-analyses of four small randomized trials revealed a
similar rate of 1-year major adverse cardiovascular and cerebrovascular events,
higher rates of target vessel revascularization and lower stroke rates for PCI.
Pooling randomized patients studies stratified by lesion complexity strengthened
the hypothesis that CABG is better in more complex LMCAD patients. However, the
randomized comparisons are affected by methodological limitations and lack power
to be conclusive. The ongoing Evaluation of XIENCE V Everolimus Eluting Stent
System Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main
Revascularization (EXCEL) trial is expected to provide a better answer on the
optimal treatment strategy for LMCAD patients. In the meantime, risk models need
to be improved and the most appropriate revascularization strategy for the
individual LMCAD patient should be chosen using a multidisciplinary heart team
that considers not only risk models but also other clinical and economic facets. Unprotected left main coronary artery (ULMCA) disease is seen in 4% of patients
who undergo angiography. Though coronary artery bypass graft surgery has
traditionally been the preferred approach to revascularization, recent major
society guidelines support the use of percutaneous coronary intervention (PCI)
in properly selected patients. This article provides an overview of recent
studies evaluating the efficacy of ULMCA PCI and looking at contemporary
approaches to the evaluation and percutaneous treatment of ULMCA disease. The
ongoing EXCEL trial will help elucidate the role of ULMCA PCI in the treatment
of left main disease compared with coronary artery bypass graft surgery. AIMS: To prospectively validate the SYNTAX Score II and forecast the outcomes of
the randomized Evaluation of the Xience Everolimus-Eluting Stent Versus Coronary
Artery Bypass Surgery for Effectiveness of Left Main Revascularization (EXCEL)
Trial.
METHODS AND RESULTS: Evaluation of the Xience Everolimus Eluting Stent vs.
Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization
is a prospective, randomized multicenter trial designed to establish the
efficacy and safety of percutaneous coronary intervention (PCI) with the
everolimus-eluting stent compared with coronary artery bypass graft (CABG)
surgery in subjects with unprotected left-main coronary artery (ULMCA) disease
and low-intermediate anatomical SYNTAX scores (<33). After completion of patient
recruitment in EXCEL, the SYNTAX Score II was prospectively applied to predict
4-year mortality in the CABG and PCI arms. The 95% prediction intervals (PIs)
for mortality were computed using simulation with bootstrap resampling (10 000
times). For the entire study cohort, the 4-year predicted mortalities were 8.5
and 10.5% in the PCI and CABG arms, respectively [odds ratios (OR) 0.79; 95% PI
0.43-1.50). In subjects with low (≤22) anatomical SYNTAX scores, the predicted
OR was 0.69 (95% PI 0.34-1.45); in intermediate anatomical SYNTAX scores
(23-32), the predicted OR was 0.93 (95% PI 0.53-1.62). Based on 4-year mortality
predictions in EXCEL, clinical characteristics shifted long-term mortality
predictions either in favour of PCI (older age, male gender and COPD) or CABG
(younger age, lower creatinine clearance, female gender, reduced left
ventricular ejection fraction).
CONCLUSION: The SYNTAX Score II indicates at least an equipoise for long-term
mortality between CABG and PCI in subjects with ULMCA disease up to an
intermediate anatomical complexity. Both anatomical and clinical characteristics
had a clear impact on long-term mortality predictions and decision making
between CABG and PCI. Unprotected left main coronary artery (ULMCA) stenosis has relatively high
prevalence and exposes patients to a high risk for adverse cardiovascular
events. The optimal revascularisation strategy (coronary artery bypass surgery
[CABG] or percutaneous coronary intervention [PCI]) for patients with complex
coronary artery disease is a topic of continuing debate. The introduction of the
newer-generation drug-eluting stents (DES) -with documented improvements in both
safety and efficacy- has prompted the interventional community to design two new
dedicated randomised trials comparing CABG and PCI: the NOBLE (Coronary Artery
Bypass Grafting Vs Drug Eluting Stent Percutaneous Coronary Angioplasty in the
Treatment of Unprotected Left Main Stenosis) and EXCEL (Evaluation of XIENCE
Everolimus Eluting Stent Versus Coronary Artery Bypass Surgery for Effectiveness
of Left Main Revascularization) trials. The aims of the present review are to
describe the similarities and contrasts between these two trials as well to
explore their future implications in ULMCA treatment. Percutaneous coronary intervention (PCI) using drug-eluting stents (DES) is
currently considered as a viable alternative to coronary artery bypass graft
surgery (CABG) for selected patients with left main coronary artery disease. The
updated results of the landmark randomized trials comparing CABG versus PCI
demonstrated comparable 5-year outcomes and are in line with the current
guidelines that designate PCI as a reasonable treatment in this disease subset.
Given that the completed randomized trials did not include contemporary DESs,
the upcoming results of the ongoing trials evaluating the performance of
new-generation DES compared with CABG (such as the EXCEL trial), may further
help to clarify the current role and future recommendations of PCI for left main
coronary artery disease. Apart from the recent stent technology, further
improvements in outcomes after PCI may be possible when it is used with an
integrated approach that combines functional concepts for decision-making,
adjunctive imaging support and optimal pharmacotherapies. |
Describe ATR-16 syndrome. | ATR-16 syndrome is due to alterations on chromosome 16p13.3, and is usually accompanied by alpha-thalassemia, mild-moderate mental retardation, dysmorphic facial features, skeletal and genitourinary malformations. | We have previously described a series of patients in whom the deletion of 1-2
megabases (Mb) of DNA from the tip of the short arm of chromosome 16 (band
16p13.3) is associated with alpha-thalassemia/mental retardation syndrome
(ATR-16). We now show that one of these patients has a de novo truncation of the
terminal 2 Mb of chromosome 16p and that telomeric sequence (TTAGGG)n has been
added at the site of breakage. This suggests that the chromosomal break, which
is paternal in origin and which probably arose at meiosis, has been stabilized
in vivo by the direct addition of the telomeric sequence. Sequence comparisons
of this breakpoint with that of a previously described chromosomal truncation
(alpha alpha)TI do not reveal extensive sequence homology. However, both
breakpoints show minimal complementarity (3-4 bp) to the proposed RNA template
of human telomerase at the site at which telomere repeats have been added.
Unlike previously characterized individuals with ATR-16, the clinical features
of this patient appear to be solely due to monosomy for the terminal portion of
16p13.3. The identification of further patients with "pure" monosomy for the tip
of chromosome 16p will be important for defining the loci contributing to the
phenotype of this syndrome. The chromosome-16 and the X-chromosome forms of alpha-thalassemia--ATR-16 and
ATR-X--exemplify 2 important causes of syndromal mental retardation. ATR-16 is a
contiguous gene syndrome which arises from loss of DNA from the tip of
chromosome 16p13.3 by truncation, interstitial deletion, or unbalanced
translocation. It provided the first example of a chromosome translocation that
could be detected by molecular analysis but not conventional cytogenetics. It
also provided the first example of a telomeric truncation giving rise to a
complex genetic syndrome. In contrast ATR-X appears to be due to mutations in a
trans-acting factor that regulates gene expression. Mutations in transcription
factors have recently been identified in a number of genetic diseases (for
example, Denys-Drash syndrome, WT1 [19]; pituitary dwarfism, PIT1 [16];
Rubinstein-Taybi syndrome, CBP [20]. Not only is this mechanism proving to be an
important cause of complex syndromes but it is providing new perspectives on
certain developmental pathways. XH2 may not be a classical transcription factor
but it is certainly involved in the regulation of gene expression, exerting its
effects on several different genes. It seems likely that other mutations in this
class of regulatory proteins will be found in patients with complex disorders
including mental retardation. In broader terms the 2 mechanisms described here
may prove to be responsible for a significant proportion of mental retardation.
However, without a feature such as alpha-thalassemia to pinpoint the area of
genome or pathways involved it may prove difficult to identify other, similarly
affected genes underlying other forms of mental retardation. As the human genome
project and rapid genome analysis evolve this problem should become less of an
obstacle. In the meantime, it is very worthwhile to continue looking for unusual
clinical associations that may point to critical genes underlying human genetic
disorders. We describe a child with alpha-thalassemia ascertained by newborn screening.
Evaluation at 9 months of age showed minor anomalies and developmental delay.
Chromosomal analysis demonstrated a de novo deletion of the most distal portion
of the short arm of chromosome 16, which contains the alpha-globin genes.
Analysis of the alpha-globin locus by Southern blot analysis did not demonstrate
altered band sizes at this locus; however, analysis of the films using
densitometry confirmed hemizygosity. This is the fifth reported case of the
ATR-16 syndrome (alpha-thalassemia retardation-16) not complicated by
duplication or deletion of other chromosomes. In the search for genetic causes of mental retardation, we have studied a
five-generation family that includes 10 individuals in generations IV and V who
are affected with mild-to-moderate mental retardation and mild, nonspecific
dysmorphic features. The disease is inherited in a seemingly autosomal domit
fashion with reduced penetrance. The pedigree is unusual because of (1) its size
and (2) the fact that individuals with the disease appear only in the last two
generations, which is suggestive of anticipation. Standard clinical and
laboratory screening protocols and extended cytogenetic analysis, including the
use of high-resolution karyotyping and multiplex FISH (M-FISH), could not reveal
the cause of the mental retardation. Therefore, a whole-genome scan was
performed, by linkage analysis, with microsatellite markers. The phenotype was
linked to chromosome 16p13.3, and, unexpectedly, a deletion of a part of 16pter
was demonstrated in patients, similar to the deletion observed in patients with
ATR-16 syndrome. Subsequent FISH analysis demonstrated that patients inherited a
duplication of terminal 3q in addition to the deletion of 16p. FISH analysis of
obligate carriers revealed that a balanced translocation between the terminal
parts of 16p and 3q segregated in this family. This case reinforces the role of
cryptic (cytogenetically invisible) subtelomeric translocations in mental
retardation, which is estimated by others to be implicated in 5%-10% of cases. We describe a child with ATR-16 [alpha-thalassemia (thal)/mental retardation],
who was referred for genetic evaluation because of minor anomalies and
developmental delay. Cytogenetic analysis demonstrated a de novo complex
rearrangement of chromosome 16. Fluorescence in situ hybridization (FISH)
analysis, using chromosome 16 subtelomeric probes, showed that this patient had
a deletion of the distal short arm of chromosome 16 that contains the
alpha-globin genes and a duplication of 16q. Analysis of the alpha-globin locus
by Southern blot showed a half normal dose of the alpha-globin gene.
Microsatellite marker studies revealed that the duplicated 16q region was
maternal in origin. Hematological studies revealed anemia, hypochromia and
occasional cells with Hb H inclusion bodies. A hematological screening for
alpha-thal should be considered in patients with mild developmental delay and a
suggestive phenotype of ATR-16 with microcytic hypochromic anemia and normal
iron status. The stellate pattern of the iris, a new finding in our patient, may
contribute to a better clinical delineation of both syndromes, ATR-16 and/or
duplication of 16qter. Alpha thalassemia retardation associated with chromosome16 (ATR-16 syndrome) is
defined as a contiguous gene syndrome resulting from haploinsufficiency of the
alpha-globin gene cluster and genes involved in mental retardation (MR). To
date, only few cases have been described which result from pure monosomy for a
deletion of 16p. In most of these cases the deletion was identified by
densitometric analysis of Southern blot results or by Fluorescent In Situ
Hybridization analysis, and these alterations have not been mapped in detail. In
this study, we have fine mapped deletions causing alpha-thalassemia within 2 Mb
from the telomere of 16p by multiplex ligation-dependent probe amplification
(MLPA). We have developed a rapid and simple test for high resolution mapping of
rearrangements involving the tip of the short arm of chromosome 16 by
incorporating 62 MLPA probes spaced approximately 10-200 kb over a region of 2
Mb from the telomere. One deletion of approximately 900 kb without MR was
identified in addition to three de novo deletions varying between 1.5 and 2 Mb
causing ATR-16 in three patients having mild MR and alpha-thalassemia. Two were
found by chance to be ATR-16 because they were included in a study to search for
telomeric loss in MR and not by hematological analysis. This would plead for
more alertness when a persistent microcytic hypochromic anemia at normal
ferritin levels is observed as suggestive for the ATR-16 syndrome. The region on
chromosome 16p for which haploinsufficiency leads to the dysmorphic features and
MR typical for ATR-16, has been narrowed down to a 800 kb region localized
between 0.9 and 1.7 Mb from the telomere. |
What is the results of inactivated ANGPLT3? | Complete ANGPTL3 deficiency caused by loss-of-function mutations of ANGPTL3 is associated with a recessive hypolipidemia | BACKGROUND: Angiopoietin-like protein 3 (ANGPTL3) affects lipid metabolism by
inhibiting the activity of lipoprotein and endothelial lipases. Angptl3 knockout
mice have marked hypolipidemia, and heterozygous carriers of ANGPLT3,
loss-of-function mutations were found among individuals in the lowest quartile
of plasma triglycerides in population studies. Recently, 4 related individuals
with primary hypolipidemia were found to be compound heterozygotes for ANGPTL3
loss-of-function mutations.
METHODS AND RESULTS: We resequenced ANGPTL3 in 4 members of 3 kindreds
originally identified for very low levels of low-density lipoprotein cholesterol
and high-density lipoprotein cholesterol (0.97±0.16 and 0.56±0.20 mmol/L,
respectively) in whom no mutations of known candidate genes for monogenic
hypobetalipoproteinemia and hypoalphalipoproteinemia had been detected. These
subjects were found to be homozygous or compound heterozygous for ANGPTL3
loss-of-function mutations (p.G400VfsX5, p.I19LfsX22/p.N147X) associated with
the absence of ANGPTL3 in plasma. They had reduced plasma levels of
triglyceride-containing lipoproteins and of HDL particles that contained only
apolipoprotein A-I and pre-β-high-density lipoprotein. In addition, their
apolipoprotein B-depleted sera had a reduced capacity to promote cell
cholesterol efflux through the various pathways (ABCA1-, SR-BI-, and
ABCG1-mediated efflux); however, these subjects had no clinical evidence of
accelerated atherosclerosis. Heterozygous carriers of the ANGPTL3 mutations had
low plasma ANGPTL3 and moderately reduced low-density lipoprotein cholesterol
(2.52±0.38 mmol/L) but normal plasma high-density lipoprotein cholesterol.
CONCLUSIONS: Complete ANGPTL3 deficiency caused by loss-of-function mutations of
ANGPTL3 is associated with a recessive hypolipidemia characterized by a
reduction of apolipoprotein B and apolipoprotein A-I-containing lipoproteins,
changes in subclasses of high-density lipoprotein, and reduced cholesterol
efflux potential of serum. Partial ANGPTL3 deficiency is associated only with a
moderate reduction of low-density lipoprotein. Mining of the genome for lipid genes has since the early 1970s helped to shape
our understanding of how triglycerides are packaged (in chylomicrons),
repackaged (in very low density lipoproteins; VLDL), and hydrolyzed, and also
how remt and low-density lipoproteins (LDL) are cleared from the circulation.
Gene discoveries have also provided insights into high-density lipoprotein (HDL)
biogenesis and remodeling. Interestingly, at least half of these key molecular
genetic studies were initiated with the benefit of prior knowledge of relevant
proteins. In addition, multiple important findings originated from studies in
mouse, and from other types of non-genetic approaches. Although it appears by
now that the main lipid pathways have been uncovered, and that only modulators
or adaptor proteins such as those encoded by LDLRAP1, APOA5, ANGPLT3/4, and
PCSK9 are currently being discovered, genome wide association studies (GWAS) in
particular have implicated many new loci based on statistical analyses; these
may prove to have equally large impacts on lipoprotein traits as gene products
that are already known. On the other hand, since 2004 - and particularly since
2010 when massively parallel sequencing has become de rigeur - no major new
insights into genes governing lipid metabolism have been reported. This is
probably because the etiologies of true Mendelian lipid disorders with overt
clinical complications have been largely resolved. In the meantime, it has
become clear that proving the importance of new candidate genes is challenging.
This could be due to very low frequencies of large impact variants in the
population. It must further be emphasized that functional genetic studies, while
necessary, are often difficult to accomplish, making it hazardous to upgrade a
variant that is simply associated to being definitively causative. Also, it is
clear that applying a monogenic approach to dissect complex lipid traits that
are mostly of polygenic origin is the wrong way to proceed. The hope is that
large-scale data acquisition combined with sophisticated computerized analyses
will help to prioritize and select the most promising candidate genes for future
research. We suggest that at this point in time, investment in sequence
technology driven candidate gene discovery could be recalibrated by refocusing
efforts on direct functional analysis of the genes that have already been
discovered. This article is part of a Special Issue entitled: From Genome to
Function. |
What percentage of rheumatoid arthritis patients are responsive to anti-TNF therapy? | Despite this, a substantial proportion of patients (approximately 30-40%) fail to respond to these potentially toxic and expensive therapies. Treatment strategies blocking tumor necrosis factor (anti-TNF) have proven very successful in patients with rheumatoid arthritis (RA), showing beneficial effects in approximately 50-60% of the patients. | The introduction of anti-TNF therapy has dramatically improved the outlook for
patients suffering from a number of inflammatory conditions including rheumatoid
arthritis and inflammatory bowel disease. Despite this, a substantial proportion
of patients (approximately 30-40%) fail to respond to these potentially toxic
and expensive therapies. Treatment response is likely to be multifactorial;
however, variation in genes or their expression may identify those most likely
to respond. By targeted testing of variants within candidate genes, potential
predictors of anti-TNF response have been reported; however, very few markers
have replicated consistently between studies. Emerging genome-wide association
studies suggest that there may be a number of genes with modest effects on
treatment response rather than a few genes of large effect. Other potential
serum biomarkers of response have also been explored including cytokines and
autoantibodies, with antibodies developing to the anti-TNF drugs themselves
being correlated with treatment failure. Treatment strategies blocking tumor necrosis factor (anti-TNF) have proven very
successful in patients with rheumatoid arthritis (RA), showing beneficial
effects in approximately 50-60% of the patients. However, a significant subset
of patients does not respond to anti-TNF agents, for reasons that are still
unknown. The aim of this study was to validate five single nucleotide
polymorphisms (SNPs) of PTPRC, CD226, AFF3, MyD88 and CHUK gene loci that have
previously been reported to predict anti-TNF outcome. In addition, two markers
of RA susceptibility, namely TRAF1/C5 and STAT4 were assessed, in a cohort of
anti-TNF-treated RA patients, from the homogeneous Greek island of Crete,
Greece. The RA patient cohort consisted of 183 patients treated with either of 3
anti-TNF biologic agents (infliximab, adalimumab and etanercept) from the Clinic
of Rheumatology of the University Hospital of Crete. The SNPs were genotyped by
TaqMan assays or following the Restriction Fragments Length Polymorphisms
(RFLPs) approach. Disease activity score in 28 joints (DAS28) at baseline and
after 6 months were available for all patients and analysis of good versus poor
response at 6 months was performed for each SNP. None of the 7 genetic markers
correlated with treatment response. We conclude that the gene polymorphisms
under investigation are not strongly predictive of anti-TNF response in RA
patients from Greece. |
Which disease is treated with semaglutide? | Semaglutide is glucagon-like peptide-1 receptor agonist that is being used for the treatment of type 2 diabetes mellitus. | The effect of semaglutide, a once-weekly human glucagon-like peptide-1 (GLP-1)
analog in development for type 2 diabetes (T2D), on the bioavailability of a
combined oral contraceptive was investigated. Postmenopausal women with T2D
(n = 43) on diet/exercise ± metformin received ethinylestradiol
(0.03 mg)/levonorgestrel (0.15 mg) once daily for 8 days before
(semaglutide-free) and during (steady-state 1.0 mg) semaglutide treatment
(subcutaneous once weekly; dose escalation: 0.25 mg 4 weeks; 0.5 mg 4 weeks;
1.0 mg 5 weeks). Bioequivalence of oral contraceptives was established if 90%CI
for the ratio of pharmacokinetic parameters during semaglutide steady-state and
semaglutide-free periods was within prespecified limits (0.80-1.25). The
bioequivalence criterion was met for ethinylestradiol area under the curve
(AUC0-24 h ) for semaglutide steady-state/semaglutide-free; 1.11 (1.06-1.15).
AUC0-24 h was 20% higher for levonorgestrel at semaglutide steady-state vs.
semaglutide-free (1.20 [1.15-1.26]). Cmax was within bioequivalence criterion
for both contraceptives. Reductions (mean ± SD) in HbA1c (-1.1 ± 0.6%) and
weight (-4.3 ± 3.1 kg) were observed. Semaglutide pharmacokinetics were
compatible with once-weekly dosing; the semaglutide dose and dose-escalation
regimen were well tolerated. Adverse events, mainly gastrointestinal, were mild
to moderate in severity. Asymptomatic increases in mean amylase and lipase were
observed. Three subjects had elevated alanine aminotransferase levels ≥3x the
upper limit of normal during semaglutide/oral contraceptive coadministration,
which were reported as adverse events, but resolved during follow-up.
Semaglutide did not reduce the bioavailability of ethinylestradiol and
levonorgestrel. OBJECTIVE: To investigate the dose-response relationship of semaglutide versus
placebo and open-label liraglutide in terms of glycemic control in patients with
type 2 diabetes.
RESEARCH DESIGN AND METHODS: This was a 12-week, randomized, double-blind phase
2 trial. Patients (n = 415) were randomized to receive a subcutaneous injection
of semaglutide once weekly without dose escalation (0.1-0.8 mg) or with dose
escalation (E) (0.4 mg steps to 0.8 or 1.6 mg E over 1-2 weeks), open-label
liraglutide once daily (1.2 or 1.8 mg), or placebo. The primary end point was
change in HbA1c level from baseline. Secondary end points included change in
body weight, safety, and tolerability.
RESULTS: Semaglutide dose-dependently reduced the level of HbA1c from baseline
(8.1 ± 0.8%) to week 12 by up to -1.7%, and body weight by up to -4.8 kg (1.6 mg
E, P < 0.001 vs. placebo). Up to 81% of patients achieved an HbA1c level of <7%.
HbA1c level and weight reductions with semaglutide 1.6 mg E were greater than
those with liraglutide 1.2 and 1.8 mg (based on unadjusted CIs), but adverse
events (AEs) and withdrawals occurred more frequently. The incidence of nausea,
vomiting, and withdrawal due to gastrointestinal AEs increased with the
semaglutide dose; most events were mild to moderate, transient, and ameliorated
by dose escalation. There were no major episodes of hypoglycemia and few cases
of injection site reactions.
CONCLUSIONS: After 12 weeks, semaglutide dose-dependently reduced HbA1c level
and weight in patients with type 2 diabetes. No unexpected safety or
tolerability concerns were identified; gastrointestinal AEs typical of
glucagon-like peptide 1 receptor agonists were mitigated by dose escalation. On
this basis, weekly semaglutide doses of 0.5 and 1.0 mg with a 4-week dose
escalation were selected for phase 3. BACKGROUND: Once-weekly glucagon-like peptide-1 receptor agonists (GLP-1RAs) are
new drugs for the treatment of type 2 diabetes.
PURPOSE: To summarize evidence for the cardiometabolic efficacy and adverse
effects of once-weekly GLP-1RAs in adults with type 2 diabetes.
DATA SOURCES: Electronic databases (PubMed, Web of Science, Cochrane Central
Register of Controlled Trials, U.S. Food and Drug Administration, European
Medicines Agency, ClinicalTrials.gov) and congress abstracts from inception
through 26 September 2015.
STUDY SELECTION: Randomized, controlled trials (≥ 24 weeks of follow-up)
studying albiglutide, dulaglutide, once-weekly exenatide, semaglutide, and
taspoglutide and reporting a cardiometabolic (primary outcome, hemoglobin A1c
[HbA1c]) or safety outcome.
DATA EXTRACTION: Extraction was done in duplicate, and risk of bias was
assessed. No language restriction was applied.
DATA SYNTHESIS: 34 trials (21,126 participants) were included. Compared with
placebo, all once-weekly GLP-1RAs reduced HbA1c and fasting plasma glucose;
taspoglutide, 20 mg, once-weekly exenatide, and dulaglutide, 1.5 mg, reduced
body weight. Among once-weekly GLP-1RAs, the greatest differences were found
between dulaglutide, 1.5 mg, and taspoglutide, 10 mg, for HbA1c (-0.4% [95% CI,
-0.7% to -0.2%]), once-weekly exenatide and albiglutide for fasting plasma
glucose (-0.7 mmol/L [CI, -1.1 to -0.2 mmol/L]; -12.6 mg/dL [CI, -19.8 to -3.6
mg/dL]), and taspoglutide, 20 mg, and dulaglutide, 0.75 mg, for body weight
(-1.5 kg [CI, -2.2 to -0.8]). Clinically marginal or no differences were found
for blood pressure, blood lipid levels, and C-reactive protein levels.
Once-weekly exenatide increased heart rate compared with albiglutide and
dulaglutide (1.4 to 3.2 beats/min). Among once-weekly GLP-1RAs, the risk for
hypoglycemia was similar, whereas taspoglutide, 20 mg, had the greatest risk for
nausea (odds ratios, 1.9 to 5.9).
LIMITATION: Data were unavailable for semaglutide, definitions of outcomes were
heterogeneous, the last-observation-carried-forward imputation method was used
in 73% of trials, and publication bias is possible.
CONCLUSION: Compared with other once-weekly GLP-1RAs, dulaglutide, 1.5 mg;
once-weekly exenatide; and taspoglutide, 20 mg, showed a greater reduction of
HbA1c, fasting plasma glucose, and body weight. Taspoglutide, 20 mg, had the
highest risk for nausea; risk for hypoglycemia among once-weekly GLP-1RAs was
similar.
PRIMARY FUNDING SOURCE: Sanofi Aventis (grant to the University of Leicester). INTRODUCTION: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are
increasingly being used for the treatment of type 2 diabetes mellitus, but
consideration of benefits and potential adverse events is required. This review
examines the state of glycemic control, weight loss, blood pressure, and
tolerability, as well as the current debate about the safety of GLP-1 RAs,
including risk of pancreatitis, pancreatic cancer, and thyroid cancer.
METHODS: A MEDLINE search (2010-2015) identified publications that discussed
longer-acting GLP-1 RAs. Search terms included GLP-1 receptor agonists,
liraglutide, exenatide, lixisenatide, semaglutide, dulaglutide, albiglutide,
efficacy, safety, pancreatitis, pancreatic cancer, and thyroid cancer. Abstracts
from the American Diabetes Association, European Association for the Study of
Diabetes, and American Association of Clinical Endocrinologists from 2010 to
2015 were also searched. Efficacy and safety studies, pooled analyses, and
meta-analyses were prioritized.
RESULTS: Research has confirmed that GLP-1 RAs provide robust glycemic control,
weight loss, and blood pressure re-duction. Current studies do not prove
increased risk of pancreatitis, pancreatic cancer, or thyroid cancer but more
trials are needed since publications that indicate safety or suggest increased
risk have methodological flaws that prevent firm conclusions to be drawn about
these rare, long-term events.
CONCLUSION: GLP-1 RA therapy in the context of individualized, patient-centered
care continues to be supported by current literature. GLP-1 RA therapy provides
robust glycemic control, blood pressure reduction, and weight loss, but studies
are still needed to address concerns about tolerability and safety, including
pancreatitis and cancer. Glucagon-like peptide-1 (GLP-1)-based therapy improves glycaemic control through
multiple mechanisms, with a low risk of hypoglycaemia and the additional benefit
of clinically relevant weight loss. Since Starling and Bayliss first proposed
the existence of intestinal secretions that stimulate the pancreas, tremendous
progress has been made in the area of incretins. As a number of GLP-1 receptor
agonists (GLP-1 RAs) continue to become available, physicians will soon face the
challenge of selecting the right option customized to their patient's needs. The
following discussion, derived from an extensive literature search using the
PubMed database, applying the terms incretin, GLP-1, exenatide, liraglutide,
albiglutide, dulaglutide, lixisenatide, semaglutide, and taspoglutide, provides
a comprehensive review of existing and upcoming molecules in the GLP-1 RA class
in terms of their structure, pharmacological profiles, efficacy, safety, and
convenience. Search Methodology: A literature search was conducted using the
PubMed database, applying the terms incretin, GLP-1, exenatide, liraglutide,
albiglutide, dulaglutide, lixisenatide, semaglutide, and taspoglutide. Relevant
articles were those that discussed structural, pharmacokinetic and
pharmacodynamic differences, classification, long-acting and short-acting GLP-1
RAs, phase 3 trials, and expert opinions. Additional targeted searches were
conducted on diabetes treatment guidelines and reviews on safety, as well as the
American Diabetes Association/European Society for Study of Diabetes (ADA/EASD)
statement on pancreatic safety. This article introduces the concept of "weekend therapy", which has now become
reality in diabetes. It briefly describes injectable and oral drugs which are
currently available, or are in advanced stages of development, for use in once
weekly administration. These include dulaglutide, exenatide QW, semaglutide,
omarigliptin and trelagliptin. The global epidemic of type 2 diabetes (T2DM) continues largely unabated due to
an increasingly sedentary lifestyle and obesogenic environment. A cost-effective
patient-centred approach, incorporating glucose-lowering therapy and
modification of cardiovascular risk factors, could help prevent the inevitable
development and progression of macrovascular and microvascular complications.
Glycaemic optimization requires patient structured education, self-management
and empowerment, and psychological support along with early and proactive use of
glucose lowering therapies, which should be delivered in a system of care as
shown by the Chronic Care Model. From diagnosis, intensive glycaemic control and
individualised care is aimed at reducing complications. In older people, the
goal is maintaining quality of life and minimizing morbidity, especially as
overtreatment increases hypoglycaemia risk. Maintaining durable glycaemic
control is challenging and complex to achieve without hypoglycaemia, weight gain
and other significant adverse effects. Overcoming patient and physician barriers
can help ensure adequate treatment initiation and intensification.
Cardiovascular safety studies with newer glucose-lowering agents are now
mandatory, with a sodium glucose co-transporter-2 inhibitor (empagliflozin), and
two glucagon like peptide-1 receptor agonists (liraglutide and semaglutide)
being the first to demonstrate superior CV outcomes compared with placebo. PURPOSE OF REVIEW: The purpose is to review evidence on cardiovascular risks and
benefits of new treatments for type 2 diabetes mellitus.
RECENT FINDINGS: In response to guidance issued by the Food and Drug
Administration, thousands of patients have been enrolled in large randomized
trials evaluating the cardiovascular effects of the three newest diabetes drug
classes: glucagon-like peptide-1 (GLP-1) receptor agonists, sodium glucose
cotransporter 2 (SGLT-2) inhibitors, and dipeptidyl peptidase-4 (DPP-4)
inhibitors. Two studies of GLP-1 receptor agonists-one of liraglutide and one of
semaglutide-have shown cardiovascular benefit relative to placebo, and one study
of the SGLT-2 inhibitor empagliflozin has shown benefit. The other published
cardiovascular outcome studies of the newest drug classes have generally
supported safety, apart from an as-yet unresolved safety concern about increased
rates of heart failure with DPP-4 inhibitors. Recent research suggests the
thiazolidinedione pioglitazone may have beneficial effects on some
cardiovascular outcomes as well, but these are counterbalanced by a known
increase of the risk of heart failure with this drug. In general, more
prospective randomized trial data is now available regarding the cardiovascular
effects of the newer diabetes drugs than on the older drug classes. New evidence
suggests that the newest diabetes drugs are safe from a cardiovascular
perspective. Evidence on benefit from at least some members of the GLP-1
receptor agonist and SGLT-2 inhibitor classes is encouraging but not yet
decisive. Cardiovascular (CV) disease remains the leading cause of death in people with
diabetes, highlighting the importance of using treatment options that do not
increase CV risk or possibly decrease CV outcomes. Since 2008, the Food and Drug
Administration has required demonstration of CV safety for all new medications
developed for the glycemic management of diabetes. Seven trials have been
published that have established CV safety for three DPP-4 inhibitors
(alogliptin, saxagliptin, and sitagliptin), three GLP-1 receptor agonists
(liraglutide, lixisenatide, and semaglutide), and one sodium-glucose
cotransporter-2 inhibitor (empagliflozin). Three of those studies also
established superiority with liraglutide, empagliflozin, and semaglutide at
reducing the composite primary endpoint of major CV events (CV death, nonfatal
myocardial infarction, and nonfatal stroke). In addition, one trial found an
increase in heart failure hospitalizations with saxagliptin. The findings of
these trials must be compared and contrasted cautiously given the differences in
patient populations and trial designs, but together they provide important
information that can be used to shape our treatment guideline recommendations
and patient-specific treatment decisions. PURPOSE: The purpose of this study was to review the results of clinical trials
assessing the cardiovascular effects of drugs for type 2 diabetes and the
cardiovascular effects of newer available drugs.
METHODS: We performed a detailed search of PubMed-listed publications, reports
from international meetings, and ongoing studies from clinical trials.gov.
FINDINGS: Currently available drugs have neutral or, in some cases, negative
effects on cardiovascular outcomes. Modern sulfonylureas appear to be safe,
although the biguanide metformin has a slightly better cardiovascular safety
profile than the sulfonylureas and is the first choice for monotherapy. The
cardiovascular tolerability of thiazolidinediones (glitazones) remains
controversial, with particularly adverse effects in patients with cardiac
failure. The cardiovascular effects of insulin in type 2 diabetes appear
neutral. Newer incretin-based therapies have been closely examined in a large
number of clinical trials, some of which are still ongoing. The dipeptidyl
peptidase-4 inhibitor (gliptins) trials to date have all found a neutral effect.
Of the glucagon-like peptide-1 (GLP-1) agonists, lixisenatide had a neutral
effect, whereas liraglutide and semaglutide had a benefit on outcomes. The
results of the sodium-glucose transporter-2 (SGLT-2) inhibitor empaglifozin
attracted interest when it was the first to report a strong benefit on
cardiovascular mortality. Liraglutide and semaglutide had a neutral effect on
cardiac failure admissions, whereas empaglifozin had a benefit. In each of the
trials, there was not a clear effect on myocardial infarction and stroke. The
mechanism of the cardiovascular benefit is debated, and further studies with
other GLP-1 agonists and SGLT-2 inhibitors are awaited.
IMPLICATIONS: After 2 decades of disappointment in attempting to control
cardiovascular progression in type 2 diabetes with careful glycemic control,
there is distinct hope that newer drugs, particularly the GLP-1 agonists and the
SGLT-2 inhibitors, will have cardiovascular benefits independent of glycemic
control. New antidiabetic drugs are being developed today that expand the range of
pharmacological intervention, in particular for patients with type 2 diabetes
(imeglimin, semaglutide, dulaglutide, FGF 21 analogue). At the same time
innovations take place that "better" the well-proven molecules, they offer new
application forms we have no experience of diabetology (osmotic pump for
exenatide, faster acting insulin aspart). New properties are brought by just the
change of concentration (insulin glargine in a concentration of 300 U/ml),
unexpected positive results are also brought by new fixed-ratio combinations of
antidiabetics (fixed-ratio combination of insulin degludec and liraglutide,
fixed-ratio combination of insulin glargine and lixisenatide). Also results of
clinical studies appear that concern molecules already in use which facilitate
the formulation of new recommendations regarding treatment type 2 diabetes.Key
words: type 2 diabetes mellitus - dulaglutide - FGF 21 - imeglimin - insulin
aspart - insulin degludek - insulin glargine - ITCA 650 - liraglutide - national
information diabetes system - semaglutide. |
What condition is usually represented by the acronym SUDEP? | The acronym SUDEP refers to Sudden Unexpected Death in Epilepsy | Sudden unexpected death in epilepsy (SUDEP) accounts for approximately 2% of
deaths in population-based cohorts of epilepsy, and up to 25% of deaths in
cohorts of more severe epilepsy. When it occurs, SUDEP usually follows a
generalised tonic-clonic seizure. Unresponsiveness, apnoea, and cardiac arrest
occur in SUDEP, rather than the typical gradual recovery. The great majority of
tonic-clonic seizures occur without difficulty and how the rare seizure
associated with SUDEP differs from others is unknown.Three mechanisms have been
proposed for SUDEP: cardiac arrhythmia, neurogenic pulmonary oedema, and
postictal suppression of brainstem respiratory centres leading to central
apnoea. Recent studies have found that the incidence of SUDEP increases with the
severity of epilepsy in the population studied. The duration of epilepsy, number
of tonic-clonic seizures, mental retardation, and simultaneous treatment with
more than two antiepileptic drugs are independent risk factors for SUDEP. Some
studies have reported that carbamazepine use, carbamazepine toxicity, and
frequent, rapid changes in carbamazepine levels, may be associated with SUDEP.
Other evidence indicates that carbamazepine could potentially increase the risk
for SUDEP by causing arrhythmia or by altering cardiac autonomic function.
However, this evidence is tenuous and most studies have not found an association
between the use of carbamazepine or any other individual antiepileptic drug and
SUDEP. There is little information regarding antiepileptic drugs other than
phenytoin and carbamazepine. The incidence of SUDEP with gabapentin, tiagabine,
and lamotrigine clinical development programmes is in the range found in other
populations with refractory epilepsy. This suggests that these individual
antiepileptic drugs are no more likely to cause SUDEP than antiepileptic drugs
in general. Best current evidence indicates that the risk of SUDEP can be
decreased by aggressive treatment of tonic-clonic seizures with as few
antiepileptic drugs as necessary to achieve complete control. At present there
is no strong reason to avoid any particular antiepileptic drug. Further studies
are needed to elucidate the potential role of individual antiepileptic drugs in
SUDEP and establish clinical relevance, if any. These studies may be challenging
to conduct and interpret because SUDEP is relatively uncommon and large numbers
will be necessary to narrow confidence intervals to determine the clinical
relevance. Also adjustments will be needed to account for the potent risks
associated with other independent factors. Epilepsy, the commonest serious neurological condition, is associated with an
increased risk in premature deaths, including an estimated 500 sudden unexpected
deaths (SUDEP) per year in the UK. In some patients seizures are associated with
cardiac arrhythmias, which are thought to be a major factor in SUDEP. Omega-3
fatty acids have been shown to reduce cardiac arrhythmias in animal studies and
to reduce sudden cardiac deaths, thought to be due to cardiac arrhythmias, in
both healthy subjects and in those who have had one myocardial infarction.
Additionally, omega-3 fatty acids in animal studies and in a small clinical
observation study have shown anti-seizure effects. Omega-3 fatty acid
supplementation in patients with refractory seizures may reduce seizures and
seizure associated cardiac arrhythmias and hence SUDEP. BACKGROUND: The National Institute for Clinical Excellence in the UK has issued
guidelines stating all individuals with epilepsy be given information about
sudden unexpected death in epilepsy (SUDEP).
METHODS: We conducted a survey of current practice among UK neurologists, using
a questionnaire sent to all practising neurologists in the UK listed on the
Association of British Neurologists database, asking under what circumstances
they told patients about SUDEP.
RESULTS: Of the validated respondents, 5% discussed SUDEP with all patients, 26%
with a majority, 61% with a few, and 7.5% with none. The commonest reasons for
SUDEP to be discussed were the patient asking about it and the neurologist
counselling people with known risk factors for SUDEP.
CONCLUSIONS: The variation we found, although not necessarily in tune with the
guidelines, reflects the variation in patients' need for knowledge about their
condition. OBJECTIVE: To evaluate risk factors for sudden and unexpected death in epilepsy
(SUDEP) in a high-risk population, i.e. patients treated in a Dutch tertiary
referral center for epilepsy.
METHODS: All patients who died between January 1999 and April 2004 while under
treatment of the epilepsy center were identified. Based on clinical data, deaths
were classified as definite, probable, possible or non-SUDEP. Potential risk
factors were compared in SUDEP cases and non-SUDEP cases.
RESULTS: SUDEP incidence was 1.24 per 1000 patient years. SUDEP patients died at
a younger age than patients from the control group of non-SUDEP deaths with
epilepsy and had an earlier onset of epilepsy. However, the frequently mentioned
factors in previous studies, i.e. male sex, generalized tonic-clonic seizures,
high seizure frequency, specific AEDs, polytherapy with several AEDs, mental
retardation, psychiatric illness and psychotropic comedication, were not found
to be correlated with SUDEP.
CONCLUSIONS: Even in this high-risk population of patients with refractory
epilepsy, treated in a tertiary referral center, SUDEP is not a frequently
occurring phenomenon. Specific risk factors could not be identified within an
already high-risk population. People with epilepsy may die suddenly and unexpectedly without a structural
pathological cause. Most SUDEP cases are likely to be related to seizures. SUDEP
incidence varies and is <1:1,000 person-years among prevalent cases in the
community and approximately 1:250 person years in specialist centres.
Case-control studies identified certain risk factors, some potentially amenable
to manipulation, including uncontrolled convulsive seizures and factors relating
to treatment and supervision. Both respiratory and cardiac mechanisms are
important. The apparent protective effect of lay supervision supports an
important role for respiratory factors, in part amenable to intervention by
simple measures. Whereas maligt tachyarrhythmias are rare during seizures,
sinus bradycardia/arrest, although infrequent, is well documented. Both types of
arrhythmias can have a genetic basis. This article reviews SUDEP and explores
the potential of coexisting liability to cardiac arrhythmias as a contributory
factor, while acknowledging that at present, bridging evidence between cardiac
inherited gene determits and SUDEP is lacking. Epilepsy is the most common serious neurological condition and sudden unexpected
death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of
death. Information concerning risk factors for SUDEP is conflicting, but high
seizure frequency is a potential risk factor. Additionally, potential
pathomechanisms for SUDEP are unknown, but it is very probable that cardiac
arrhythmias during and between seizures or transmission of epileptic activity to
the heart via the autonomic nervous system potentially play a role. In parallel,
studies have shown a link between vitamin D dysfunction and epilepsy. Moreover,
several evidences in the literature suggest an association between low vitamin D
and seizures, indicating the possibility of anticonvulsant properties of this
hormone. Quite interesting, a growing body of data suggests that low vitamin D
levels may adversely affect cardiovascular health, directly associated with
death from heart failure and sudden cardiac death. In view of the above
findings, our research group focused in this review article that SUDEP, at least
in some cases, could be related with low vitamin D levels. People with epilepsy may die unexpectedly without a clear structural or
pathologic cause. This condition is called sudden unexpected death in epilepsy
(SUDEP), and it accounts for a large proportion of deaths among people with
epilepsy. SUDEP incidence rates vary with the cohort studied, ranging from 0.35
per 1,000 person-years of follow-up in population-based studies to 9.3 per 1,000
person-years in patients with refractory epilepsy. Although many studies have
been performed, the causes of SUDEP are not understood. However, even without
precise knowledge of the underlying pathogenic mechanism(s), SUDEP prevention
could start with the identification of the most prominent risk factors. SUDEP
seems to occur more commonly during sleep and it preferentially affects young
adults with medically intractable epilepsy (especially tonic-clonic seizures),
individuals who also have neurologic comorbidity, and patients receiving
antiepileptic drug polytherapy. This article reviews the clinical features
associated with SUDEP and suggests preventive measures for this condition. Epilepsy is the main neurological condition in children and adolescents.
Unfortunately patients with medical refractory epilepsy are more susceptible for
clinical complications and death. We report a prospectively evaluated cohort of
children followed for approximately 10 years. Fifty-three of 1012 patients died.
Forty-two patients died due to epilepsy or its clinical complications and the
main causes of death were pneumonia (in 16 cases), sepsis (in 9 patients),
status epilepticus (in 8 patients). In 11 patients cause of death was sudden
unexpected death in epilepsy (SUDEP). Mental retardation was significantly more
frequent in patients who did not die from SUDEP. SUDEP may be a significant
condition associated with mortality in children and adolescents with epilepsy. Sudden unexpected death in epilepsy (SUDEP) is a category of death in people
with epilepsy occurring in the absence of a known structural cause of death and
is most likely heterogeneous with regard to mechanisms and circumstances. SUDEP
is particularly difficult to investigate in research studies for several
reasons, including its relatively low incidence, its unpredictable occurrence
often in unwitnessed settings, and its low rate of complete autopsy
examinations. Over the past two decades, two complementary definitions have been
used in most SUDEP studies, but often with variations. We propose here a unified
SUDEP definition and classification to resolve current ambiguities and to
retrieve cases that would not have been further studied if the previous
definitions were used. The proposed Unified SUDEP Definition and Classification
contains, in addition to concepts inherent in the previous definitions, nine
main recommendations. (1) The word "unexpected," and not the word "unexplained,"
should be uniformly used in the term SUDEP. (2) The SUDEP category should be
applied when appropriate, whether or not a terminal seizure is known to have
occurred. (3) The "Possible SUDEP" category should be used only for cases with
competing causes of death, with cases left unclassified when data are
insufficient to reasonably permit their classification. (4) Cases that would
otherwise fulfill the definition of SUDEP should be designated as "SUDEP Plus"
when evidence indicates that a preexisting condition, known before or after
autopsy, could have contributed to the death, which otherwise is classified as
SUDEP (e.g., coronary insufficiency with no evidence of myocardial infarction or
long-QT syndrome with no documented primary ventricular arrhythmia leading to
death). (5) To be considered SUDEP, the death should have occurred within 1 h
from the onset of a known terminal event. (6) For status epilepticus as an
exclusion criterion for SUDEP, the duration of seizure activity should be 30 min
or more. (7) A specific category of SUDEP due to asphyxia should not be
designated, the distinction being largely impractical on circumstantial or
autopsy evidence, with more than one mechanism likely to be contributory in many
cases. (8) Death occurring in water but without circumstantial or autopsy
evidence of submersion should be classified as "Possible SUDEP." If any evidence
of submersion is present, the death should not be classified as SUDEP. (9) A
category of "Near-SUDEP" should be agreed to include cases in which
cardiorespiratory arrest was reversed by resuscitation efforts with subsequent
survival for more than 1 h. Scenarios that demonstrate the basis for each SUDEP
category are described. If disagreement exists about which category fits a
particular case, we suggest the use of consensus decision by a panel of informed
reviewers to adjudicate the classification of the case. PURPOSE: Sudden unexplained death in epilepsy (SUDEP) is uncommon. Discussing
the risk of SUDEP can be difficult, particularly in those where the risk is
considered low, and previous studies have suggested that clinical practice
varies widely. The Scottish Intercollegiate Guidelines Network (SIGN) suggest
information on SUDEP is "essential" and National Institute of Clinical
Excellence (NICE) recommend that "tailored information on the person's relative
risk of SUDEP should be part of the counselling process…". The study aimed to
evaluate if discussion of SUDEP risk is being documented in clinical records and
to determine if there is an association between documented discussion and risk
factors for SUDEP.
METHODS: A retrospective case note review was undertaken in those with an
established diagnosis of epilepsy attending clinic between 1st January 2009 and
30th June 2009.
RESULTS: Overall, a documented SUDEP discussion was noted in 14/345 (4%) cases.
Patients were statistically more likely to have a documented SUDEP discussion if
they had ongoing generalised tonic-clonic seizures, with a trend also towards
informing those non-compliant with medication.
CONCLUSION: Patients were more likely to be informed of SUDEP if they had
potentially modifiable risk factors identified. There was, however, no
documented evidence to suggest that SUDEP is being discussed in the majority of
cases. Among people with epilepsy, there is a 20-fold higher risk of dying suddenly and
unexpectedly compared with the general population. This phenomenon is called
sudden unexpected death in epilepsy (SUDEP) and the term is used when sudden
death occurs in an otherwise reasonably healthy person with epilepsy and the
autopsy is unrevealing. In most cases, SUDEP occurs during sleep and is
unwitnessed. Risk factors for SUDEP include the presence or number of
generalized tonic-clonic seizures (GTCS), nocturnal seizures, young age at
epilepsy onset, longer duration of epilepsy, dementia, absence of
cerebrovascular disease, asthma, male gender, symptomatic aetiology of epilepsy
and alcohol abuse. Suggested factors predisposing to SUDEP have included
long-QT-related mutations, impaired serotonergic brain stem control of
respiration, altered autonomic control and seizures with a pronounced postictal
suppression and respiratory compromise. Final events that may lead up to SUDEP
are a postictal CNS shutdown with pronounced EEG suppression, ictal or postictal
apnoea, and ictal cardiac arrhythmia. It is unknown whether antiepileptic drugs
(AEDs) modify the risk for SUDEP. Studies have consistently found that the
presence or number of GTCS is associated with an increased risk for SUDEP. Since
continued presence of GTCS clearly necessitates the use of AEDs, both factors
must be taken into account to determine whether one or both increases the risk
for SUDEP. Some studies suggest that AEDs, such as lamotrigine and
carbamazepine, may increase the risk of SUDEP, but rarely adjust for GTCS. Other
studies, which have found that AEDs are associated with a decreased SUDEP risk,
either adjust for the number of GTCS or are meta-analyses of randomized clinical
trials. Studies assessing the impact of AEDs on the risk for SUDEP are limited
because SUDEP is a rare event, making randomized clinical trials impossible to
conduct. Observational studies focus on whether or not an AED was prescribed.
When postmortem AED concentrations are assessed they are usually low or absent,
perhaps due to sampling in deceased individuals, making it difficult to fully
resolve whether AEDs increase or decrease SUDEP risk. Despite these caveats, the
evidence suggests that AEDs are not associated with an increased risk for SUDEP
on a population level, although some individuals may be susceptible to effects
of AEDs. Recent evidence from a meta-analysis of randomized clinical trials of
adjunctive AEDs at efficacious doses provides strong support for AED treatment
as mono- or polytherapy to increase seizure control and protect against SUDEP in
patients with refractory epilepsy. For patients for whom seizure control is
unattainable, supervision or monitoring may prevent SUDEP, though this has never
been formally tested. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of
epilepsy-related mortality, but how to predict which patients are at risk and
how to prevent it remain uncertain. The underlying pathomechanisms of SUDEP are
still largely unknown, but the general consensus is that seizures somehow
disrupt normal cardiac or respiratory physiology leading to death. However, the
proportion of SUDEP cases exhibiting cardiac or respiratory dysfunction as a
critical factor in the terminal cascade of events remains unresolved. Although
many general risk factors for SUDEP have been identified, the development of
reliable patient-specific biomarkers for SUDEP is needed to provide more
accurate risk prediction and personalized patient management strategies. Studies
in animal models and patient groups have revealed at least nine different
brain-heart genes that may contribute to a genetic susceptibility for SUDEP,
making them potentially useful as genomic biomarkers. This review summarizes
data on the relationship between these neurocardiac genes and SUDEP, discussing
their brain-heart expression patterns and genotype-phenotype correlations in
mouse models and people with epilepsy. These neurocardiac genes represent good
first candidates for evaluation as genomic biomarkers of SUDEP in future
studies. The development of validated reliable genomic biomarkers for SUDEP has
the potential to transform the clinical treatment of epilepsy by pinpointing
patients at risk of SUDEP and allowing optimized, genotype-guided therapeutic
and prevention strategies. Worldwide, mortality associated with epilepsy is a matter of grave concern. The
mortality rate in epileptic population is two to three times more than that of
the general population. Sudden unexplained death in epilepsy, better known as
sudden unexpected death in epilepsy (SUDEP), is a mysterious and rare condition,
in which typically young or middle-aged people with epilepsy die without a
clearly defined cause. At times, this may raise a strong suspicion of foul play
and raise several medico-legal issues. There may be several different underlying
mechanisms but most research has focused on seizure-related cerebral and
respiratory depression, cardiac arrhythmia and autonomic dysfunction. In recent
years, some significant risk factors have been recognized and strategies have
been suggested that could be useful in prevention of SUDEP. Present
communication provides some of the updates on new advances in prevention of
SUDEP as well as highlights related medico-legal issues. Sudden unexpected death in epilepsy (SUDEP) is the most tragic potential outcome
of epilepsy. Despite recommendations from epilepsy organizations in the United
Kingdom and the United States, many neurologists choose not to discuss the risk
of SUDEP with their patients with epilepsy. Yet, the literature clearly
demonstrates that people with epilepsy and their caregivers want to know more
about SUDEP. When health care providers do not provide information, people with
epilepsy turn to other sources, risking misinformation and potentially
increasing anxiety and distress. Sharing accurate information about SUDEP can
optimize epilepsy self-management and engage the person with epilepsy as a
partner in their own care. Information about SUDEP must be part of the
comprehensive education given to all people with epilepsy. OBJECTIVES: Sudden unexpected death in epilepsy (SUDEP) is a major cause of
mortality in epilepsy. Despite its devastating consequences, SUDEP appears to be
poorly discussed with patients by health professionals. The risk of causing
psychological distress to the patient is highlighted as a reason for not
discussing SUDEP. However, no studies have assessed the adult patients' views on
this important question. We conducted this cross-sectional study to evaluate the
awareness and perspectives on SUDEP among adult patients with epilepsy.
METHODS: One hundred five consecutive adult patients with epilepsy, referred to
the Epilepsy Clinic of a tertiary hospital between October 2012 and November
2013, were surveyed to ascertain their views and understanding of SUDEP. The
data were analyzed using logistic regression to explore the association between
patients' awareness of SUDEP and characteristics such as age, gender, duration
of epilepsy, level of education, and employment.
RESULTS: Awareness of SUDEP among adult patients with epilepsy was poor (14.3%).
However, the vast majority (89.5%) wished to be informed about SUDEP, and 59%
requested detailed information. The treating neurologist was considered to be
the most appropriate source of SUDEP information by 85.6% of patients.
Multivariable analysis of the data showed no association between characteristics
of patients (age, gender, duration of epilepsy, level of education, and
employment) and their awareness of SUDEP or desire to get SUDEP-related
information.
CONCLUSIONS: Our study suggests that the majority of adult patients wish to be
informed about SUDEP. This is in contrast to the general reluctance of medical
professionals to inform all patients routinely about this condition. OBJECTIVE: Most cases of sudden unexpected death in epilepsy (SUDEP) follow a
seizure, and most deaths occur while people are in bed, presumably sleeping.
Nocturnal seizures are reported to be a risk factor for SUDEP. People with
nocturnal frontal lobe epilepsy (NFLE) have seizures predomitly or
exclusively during sleep, often many times per night. The present study aimed to
assess whether NFLE represents a high-risk condition for SUDEP.
METHODS: The present study retrospectively assessed the incidence of SUDEP in a
cohort reconstructed from a dedicated database of consecutive patients referred
to the Epilepsy and Sleep Centres of the Institute of Neurological Sciences of
Bologna from 1980 to 2012 with: (1) a diagnosis of NFLE, (2) at least 90% of
seizures during sleep, and (3) at least one-year of follow-up.
RESULTS: One hundred and three people were included. The median time from
seizure onset to last observation was 26 years, equal to a follow-up of 2789
person-years. One person died of SUDEP during the follow-up period. The
incidence rate of SUDEP was 0.36 per 1000 person-years (95% CI 0.01 to 2.0).
CONCLUSIONS: The incidence of SUDEP in the participant population was not higher
than the rates previously reported in prevalent epilepsy populations (0.4 to 2.3
per 1000 person-years). The low prevalence of SUDEP might reflect the low
occurrence of generalised tonic-clonic seizures in people with NFLE. Sudden unexpected death in epilepsy (SUDEP) remains a leading cause of
epilepsy-related death, and yet, its pathogenic mechanisms remain ill-defined.
Although epidemiological studies of SUDEP in heterogenous populations have
established a number of clinical associations, evaluation and stratification of
individual risk remains difficult. Thus, potential markers as predictors of risk
of SUDEP are important not only clinically but also for research on SUDEP
prevention. Recordings from rare monitored cases of SUDEP demonstrate postictal
generalized EEG suppression after terminal seizures, raising expectations that
postictal generalized EEG suppression may identify individuals at higher risk.
In this review, we consider the literature on postictal generalized EEG
suppression and evaluate its relevance and utility as a possible marker of
SUDEP. Seizure-related cardiac arrhythmias are frequently reported and have been
implicated as potential pathomechanisms of Sudden Unexpected Death in Epilepsy
(SUDEP). We attempted to identify clinical profiles associated with various
(post)ictal cardiac arrhythmias. We conducted a systematic search from the first
date available to July 2013 on the combination of two terms: 'cardiac
arrhythmias' and 'epilepsy'. The databases searched were PubMed, Embase (OVID
version), Web of Science and COCHRANE Library. We attempted to identify all case
reports and case series. We identified seven distinct patterns of (post)ictal
cardiac arrhythmias: ictal asystole (103 cases), postictal asystole (13 cases),
ictal bradycardia (25 cases), ictal atrioventricular (AV)-conduction block (11
cases), postictal AV-conduction block (2 cases), (post)ictal atrial
flutter/atrial fibrillation (14 cases) and postictal ventricular fibrillation (3
cases). Ictal asystole had a mean prevalence of 0.318% (95% CI 0.316% to 0.320%)
in people with refractory epilepsy who underwent video-EEG monitoring. Ictal
asystole, bradycardia and AV-conduction block were self-limiting in all but one
of the cases and seen during focal dyscognitive seizures. Seizure onset was
mostly temporal (91%) without consistent lateralisation. Postictal arrhythmias
were mostly found following convulsive seizures and often associated with (near)
SUDEP. The contrasting clinical profiles of ictal and postictal arrhythmias
suggest different pathomechanisms. Postictal rather than ictal arrhythmias seem
of greater importance to the pathophysiology of SUDEP. The aim of this study was to review population autopsy data on epilepsy-related
deaths (ERD) in Queensland, Australia, to establish the incidence of
autopsy-confirmed sudden unexpected death in epilepsy (SUDEP), explore factors
associated with SUDEP, and determine if complete autopsy examinations of SUDEP
were performed. All autopsy reports for a 5year period in Queensland were
electronically searched for the terms 'epilepsy' or 'seizure'. The identified
reports were reviewed, and data were extracted for all ERD. In the study period,
175 ERD were identified from autopsy records (123 SUDEP, 34 accident-related, 3
due to status epilepticus). From data available on the prevalence of epilepsy in
Queensland (National Health Survey), the incidence of autopsy-confirmed SUDEP
was 0.7 per 1000 person years (95% confidence interval 0.5-1.2 per 1000 person
years). The factors associated with SUDEP were male sex (for those >18 years)
and subtherapeutic anticonvulsant medication levels (found in 55%). Where
recorded, the majority of deaths happened in the person's usual residence (90%),
were overnight (70%) and unwitnessed (87%), with the person found prone (74%),
in or adjacent to their bed (49%) and with signs of proximate seizure (60%). A
complete autopsy was undertaken for only 59% of cases, the majority in urban
locations. This study provides support for an unwitnessed overnight seizure
being a key factor in autopsy-confirmed SUDEP in Queensland. The baboon represents a natural model for genetic generalized epilepsy and
sudden unexpected death in epilepsy (SUDEP). In this retrospective study,
cerebrospinal fluid (CSF) monoamine metabolites and scalp electroencephalography
(EEG) were evaluated in 263 baboons of a pedigreed colony. CSF monoamine
abnormalities have been linked to reduced seizure thresholds, behavioral
abnormalities and SUDEP in various animal models of epilepsy. The levels of
3-hydroxy-4-methoxyphenylglycol, 5-hydroxyindolacetic acid and homovanillic acid
in CSF samples drawn from the cisterna magna were analyzed using
high-performance liquid chromatography. These levels were compared between
baboons with seizures (SZ), craniofacial trauma (CFT) and asymptomatic, control
(CTL) baboons, between baboons with abnormal and normal EEG studies. We
hypothesized that the CSF levels of major monoaminergic metabolites (i.e.,
dopamine, serotonin and norepinephrine) associate with the baboons'
electroclinical status and thus can be used as clinical biomarkers applicable to
seizures/epilepsy. However, despite apparent differences in metabolite levels
between the groups, usually lower in SZ and CFT baboons and in baboons with
abnormal EEG studies, we did not find any statistically significant differences
using a logistic regression analysis. Significant correlations between the
metabolite levels, especially between 5-HIAA and HVA, were preserved in all
electroclinical groups. While we were not able to demonstrate significant
differences in monoamine metabolites in relation to seizures or EEG markers of
epilepsy, we cannot exclude the monoaminergic system as a potential source of
pathogenesis in epilepsy and SUDEP. A prospective study evaluating serial CSF
monoamine levels in baboons with recently witnessed seizures, and evaluation of
abnormal expression and function of monoaminergic receptors and transporters
within epilepsy-related brain regions, may impact the electroclinical status. |
Which proteins does the yeast Cleavage and Polyadenylation Complex contain? | The proteins Nrd1, Rap1, Trf4, Rrp6, Ssu72, Cstf64, Pcf11 and PAP are the major components of the 3' cleavage and polyadenylation complex. | Eukaryotic RNA polymerase II transcribes precursors of mRNAs and of
non-protein-coding RNAs such as snRNAs and snoRNAs. These RNAs have to be
processed at their 3' ends to be functional. mRNAs are matured by cleavage and
polyadenylation that require a well-characterized protein complex. Small RNAs
are also subject to 3' end cleavage but are not polyadenylated. Here we show
that two newly identified proteins, Pti1p and Ref2p, although they were found
associated with the pre-mRNA 3' end processing complex, are essential for yeast
snoRNA 3' end maturation. We also provide evidence that Pti1p probably acts by
uncoupling cleavage and polyadenylation, and functions in coordination with the
Nrd1p-dependent pathway for 3' end formation of non-polyadenylated transcripts. We describe the cloning and characterization of a human homolog of the yeast
transcription/RNA-processing factor Ssu72, following a yeast two-hybrid screen
for pRb-binding factors in the prostate gland. Interaction between hSsu72 and
pRb was observed in transfected mammalian cells and involved multiple domains in
pRb; however, so far, mutual effects of these two factors could not be
demonstrated. Like the yeast counterpart, mammalian Ssu72 associates with TFIIB
and the yeast cleavage/polyadenylation factor Pta1, and exhibits intrinsic
phosphatase activity. Mammals contain a single ssu72 gene and a few pseudogenes.
During mouse embryogenesis, ssu72 was highly expressed in the nervous system and
intestine; high expression in the nervous system persisted in adult mice and was
also readily observed in multiple human tumor cell lines. Both endogenous and
ectopically expressed mammalian Ssu72 proteins resided primarily in the
cytoplasm and only partly in the nucleus. Interestingly, fusion to a strong
nuclear localization signal conferred nuclear localization only in a fraction of
transfected cells, suggesting active tethering in the cytoplasm. Suppression of
ssu72 expression in mammalian cells by siRNA did not reduce
proliferation/survival, and its over-expression did not affect transcription of
candidate genes in transient reporter assays. Despite high conservation, hssu72
was unable to rescue an ssu72 lethal mutation in yeast. Together, our results
highlight conserved and mammalian specific characteristics of mammalian ssu72. Transcription termination by RNA polymerase II is coupled to transcript 3' end
formation. A large cleavage and polyadenylation complex containing the major
poly(A) polymerase Pap1 produces mRNA 3' ends, whereas those of
nonpolyadenylated snoRNAs in yeast are formed either by endonucleolytic cleavage
or by termination, followed by trimming by the nuclear exosome. We show that
synthesis of independently transcribed snoRNAs involves default polyadenylation
of two classes of precursors derived from termination at a main
Nrd1/Nab3-dependent site or a "fail-safe" mRNA-like signal. Poly(A) tails are
added by Pap1 to both forms, whereas the alternative poly(A) polymerase Tfr4
adenylates major precursors and processing intermediates to facilitate further
polyadenylation by Pap1 and maturation by the exosome/Rrp6. A more important
role of Trf4/TRAMP, however, is to enhance Nrd1 association with snoRNA genes.
We propose a model in which polyadenylation of pre-snoRNAs is a key event
linking their transcription termination, 3' end processing, and degradation. To discover antifungal treatments that possess the desired characteristics of
broad spectrum activity, a strong safety profile, and oral bioavailability, new
discovery strategies must be implemented to identify structural classes of
molecules capable of combating these microorganisms. One such technique that has
been implemented is the Candida albicans Fitness Test, a whole cell screening
platform capable of delineating the mechanism of action of compounds that
demonstrate activity against the clinically relevant pathogenic fungus, C.
albicans. Screening crude natural product extracts with this technology has
resulted in the identification of a novel family of antifungal natural products,
named the parnafungins, which inhibit the enzyme polyadenosine polymerase (PAP),
a key component of the mRNA cleavage and polyadenylation complex. Owing to the
rapid interconversion of the structural and stereoisomers of the parnafungins at
neutral pH, the determination of the structural isomer with the highest affinity
for PAP with standard biochemical assays has not been possible. Herein, we
present an application of affinity-selection/mass spectrometry (AS-MS) to
determine that the "straight" parnafungin structural isomer (parnafungin A)
binds preferentially to PAP compared to the "bent" structural isomer
(parnafungin B). The general transcription factor TFIIB plays a central role in preinitiation
complex (PIC) assembly and the recruitment of RNA polymerase II (RNA pol II) to
the promoter. Recent studies have revealed that TFIIB engages in contact with
the transcription termination region and also with complexes that are involved
in 3' end processing and/or termination. Here we report that TFIIB can be
phosphorylated within the N terminus at serine 65 in vivo and that the
phosphorylated form of TFIIB is present within (PICs). Surprisingly, TFIIB
serine 65 phosphorylation is required after the phosphorylation of serine 5 of
RNA pol II C-terminal domain (CTD) has occurred, but before productive
transcription initiation begins. We show that phosphorylation of TFIIB at serine
65 regulates the interaction between TFIIB and the CstF-64 component of the CstF
3' cleavage and polyadenylation complex. This directs the recruitment of CstF
(cleavage stimulatory factor) to the terminator and also the recruitment of the
CstF and CPSF (cleavage and polyadenylation specific factor) complexes to the
promoter. Our results reveal that phosphorylation of TFIIB is a critical event
in transcription that links the gene promoter and terminator and triggers
initiation by RNA pol II. Gene loops have been described in different organisms from yeast to human and
form through interaction between components of the transcription pre-initiation
complex and Ssu72, a member of the 3' end cleavage and polyadenylation complex.
A recent study by Tan-Wong et al. reports a new role for gene loops in promoting
ORF transcription directionality from otherwise bidirectional promoters. In Saccharomyces cerevisiae, short noncoding RNA (ncRNA) generated by RNA
polymerase II (Pol II) are terminated by the NRD complex consisting of Nrd1,
Nab3, and Sen1. We now show that Pcf11, a component of the cleavage and
polyadenylation complex (CPAC), is also generally required for NRD-dependent
transcription termination through the action of its C-terminal domain
(CTD)-interacting domain (CID). Pcf11 localizes downstream from Nrd1 on NRD
terminators, and its recruitment depends on Nrd1. Furthermore, mutation of the
Pcf11 CID results in Nrd1 retention on chromatin, delayed degradation of ncRNA,
and restricted Pol II CTD Ser2 phosphorylation and Sen1-Pol II interaction.
Finally, the pcf11-13 and sen1-1 mutant phenotypes are very similar, as both
accumulate RNA:DNA hybrids and display Pol II pausing downstream from NRD
terminators. We predict a mechanism by which the exchange of Nrd1 and Pcf11 on
chromatin facilitates Pol II pausing and CTD Ser2-P phosphorylation. This in
turn promotes Sen1 activity that is required for NRD-dependent transcription
termination in vivo. |
Which disease can be categorized using the Koos grading system? | Koos grading system is used for vestibular schwannoma. | PURPOSE: To evaluate and compare outcomes for patients with vestibular
schwannoma (VS) treated in a single institution with linac-based stereotactic
radiosurgery (SRS) or by fractionated stereotactic radiotherapy (SRT).
METHODS AND MATERIALS: One hundred and nineteen patients (SRS = 78, SRT = 41)
were treated. For both SRS and SRT, beam shaping is performed by a
mini-multileaf collimator. For SRS, a median single dose of 12.5 Gy (range,
11-14 Gy), prescribed to the 80% isodose line encompassing the target, was
applied. Of the 42 SRT treatments, 32 treatments consisted of 10 fractions of
3-4 Gy, and 10 patients received 25 sessions of 2 Gy, prescribed to the 100%
with the 95% isodose line encompassing the planning target volume. Mean largest
tumor diameter was 16.6 mm in the SRS and 24.6 mm in the SRT group. Local tumor
control, cranial nerve toxicity, and preservation of useful hearing were
recorded. Any new treatment-induced cranial nerve neuropathy was scored as a
complication.
RESULTS: Median follow-up was 62 months (range, 6-136 months), 5 patients
progressed, resulting in an overall 5-year local tumor control of 95%. The
overall 5-year facial nerve preservation probability was 88% and facial nerve
neuropathy was statistically significantly higher after SRS, after prior
surgery, for larger tumors, and in Koos Grade ≥3. The overall 5-year trigeminal
nerve preservation probability was 96%, not significantly influenced by any of
the risk factors. The overall 4-year probability of preservation of useful
hearing (Gardner-Robertson score 1 or 2) was 68%, not significantly different
between SRS or SRT (59% vs. 82%, p = 0.089, log rank).
CONCLUSION: Linac-based RT results in good local control and acceptable clinical
outcome in small to medium-sized vestibular schwannomas (VSs). Radiosurgery for
large VSs (Koos Grade ≥3) remains a challenge because of increased facial nerve
neuropathy. AIM OF THE STUDY: To evaluate the results of facial nerve (FN) grafting using
great auricular cable graft and fibrin glue without suturing to palliate FN
disruption after removal of large cerebellopontine angle (CPA) vestibular
schwannoma (VS) or facial nerve schwannoma (FNS). To assess whether tumor size
and origin influenced the results.
STUDY DESIGN AND SETTING: Retrospective review of all patients having undergone
removal of FNS/VS and needing intraoperative FN repair between 2001 and 2011.
INTERVENTION: FN was rehabilitated using great auricular nerve cable graft and
fibrin glue (Tisseal) without stitching suture.
MAIN OUTCOME MEASURES: All data recorded were reviewed to access age, sex, tumor
type, and tumor size according to the Koos classification and presenting
symptoms. FN function was evaluated preoperatively and at 18 months using the
House-Brackmann (HB) grading system.
RESULTS: Among the 595 patients operated for CPA schwannomas in this period, 15
patients (2.5%) underwent FN repair, including 7 cases of FNS and 8 cases of VS.
Tumor removal was total in all cases. FN recovery was HB3 in 13 cases (86.7%)
and HB4 in 2. The mean time to the first clinical signs of facial reinnervation
was 10 months (6-12 mo). No significant relation was found between postoperative
facial function and tumor size or type, even if all cases of preoperative FP
were noted in FNS.
CONCLUSION: Immediate FN reconstruction with fibrin glue-aided greater auricular
nerve graft can effectively restore FN function with excellent outcomes. The
results seem better than those observed by other authors using sutured grafts or
delayed hypoglossal-facial nerve anastomosis. BACKGROUND: The aim of this study was to analyze complications of vestibular
schwannoma (VS) microsurgery.
MATERIAL AND METHODS: A retrospective study was performed in 333 patients with
unilateral vestibular schwannoma indicated for surgical treatment between
January 1997 and December 2012. Postoperative complications were assessed
immediately after VS surgery as well as during outpatient followup.
RESULTS: In all 333 patients microsurgical vestibular schwannoma (Koos grade 1:
12, grade 2: 34, grade 3: 62, and grade 4: 225) removal was performed. The main
neurological complication was facial nerve dysfunction. The intermediate and
poor function (HB III-VI) was observed in 124 cases (45%) immediately after
surgery and in 104 cases (33%) on the last followup. We encountered disordered
vestibular compensation in 13%, permanent trigeminal nerve dysfunction in 1%,
and transient lower cranial nerves (IX-XI) deficit in 6%. Nonneurological
complications included CSF leakage in 63% (lateral/medial variant: 99/1%),
headache in 9%, and intracerebral hemorrhage in 5%. We did not encounter any
case of meningitis.
CONCLUSIONS: Our study demonstrates that despite the benefits of advanced
high-tech equipment, refined microsurgical instruments, and highly developed
neuroimaging technologies, there are still various and significant complications
associated with vestibular schwannomas microsurgery. BACKGROUND: Facial nerve preservation surgery for large vestibular schwannomas
is a novel strategy for maintaining normal nerve function by allowing residual
tumor adherent to this nerve or root-entry zone.
OBJECTIVE: To report, in a retrospective study, outcomes for large Koos grade 3
and 4 vestibular schwannomas.
METHODS: After surgical treatment for vestibular schwannomas in 52 patients
(2004-2013), outcomes included extent of resection, postoperative hearing, and
facial nerve function. Extent of resection defined as gross total, near total,
or subtotal were 7 (39%), 3 (17%), and 8 (44%) in 18 patients after retrosigmoid
approaches, respectively, and 10 (29.5%), 9 (26.5%), and 15 (44%) for 34
patients after translabyrinthine approaches, respectively.
RESULTS: Hearing was preserved in 1 (20%) of 5 gross total, 0 of 2 near-total,
and 1 (33%) of 3 subtotal resections. Good long-term facial nerve function
(House-Brackmann grades of I and II) was achieved in 16 of 17 gross total (94%),
11 of 12 near-total (92%), and 21 of 23 subtotal (91%) resections. Long-term
tumor control was 100% for gross total, 92% for near-total, and 83% for subtotal
resections. Postoperative radiation therapy was delivered to 9 subtotal
resection patients and 1 near-total resection patient. Follow-up averaged 33
months.
CONCLUSION: Our findings support facial nerve preservation surgery in becoming
the new standard for acoustic neuroma treatment. Maximizing resection and close
postoperative radiographic follow-up enable early identification of tumors that
will progress to radiosurgical treatment. This sequential approach can lead to
combined optimal facial nerve function and effective tumor control rates. BACKGROUND: The membranous structure of vestibular schwannoma is an important
factor in its surgical treatment. Herein, we report intraoperative and
microscopic findings relating to an outermost dura-like membrane in cases of
vestibular schwannoma and the importance of these findings.
METHODS: Intraoperative findings of 16 cases of vestibular schwannoma treated
with an initial surgery were studied with an aim to determine if the cases had a
dura-like membrane. Then we studied microscopic findings of the dura-like
membrane using hematoxylin and eosin, Masson trichrome, and immunohistochemical
staining in 2 cases.
RESULTS: The dura-like membrane was observed in 8 out of 16 cases. The average
tumor size of the cases that had a dura-like membrane was 30 ± 8.1 mm, and Koos
grading 4 was in 7 out of 8 cases, and one was grade 3. In cases without a
dura-like membrane, these values were significantly smaller, with an average
tumor size of 12.8 ± 5.2 mm, and Koos grading 4 was only in 1 of 8 cases, grade
3 was in 2 cases, and other 5 cases were grade 2. The outermost dura-like
membrane enveloped the vestibular schwannoma around the internal acoustic meatus
and was continuous with the dura mater. Reactive angiogenesis was observed in
the dura mater. Microscopic findings proved its continuity with the dura mater.
In one case, the facial nerve was damaged before it was identified during
subcapsular dissection. In that case, the dura-like membrane negatively affected
our ability to identify the facial nerve.
CONCLUSIONS: A dura-like membrane sometimes envelops vestibular schwannoma
around the internal acoustic meatus. Recognition of this membranous structure is
important for the surgical preservation of facial and acoustic nerves. |
What is the inheritance of the glucose-6-phosphate dehydrogenase (G6PD) deficiency? | Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the commonest red cell enzymopathy in humans and has a recessive X-linked inheritance. | Severe red cell glucose-6-phosphate dehydrogenase (G-6-PD) deficiency has been
found in an 'aboriginal' Finnish family. 2 male and 9 female carriers of the
variant G-6-PD were studied. The genetic pattern is consistent with x-linked
recessive inheritance and the defect is associated with drug (primaquine)
induced haemolysis. This was demonstrated by enzyme deficient red cell
(51Cr-labelled) survival studies on a normal volunteer recipient. In addition,
one of the hemizygotes studied had a slight chronic nonspherocytic haemolytic
disorder. The partially purified enzyme had many of the characteristics of
G-6-PD Mediterranean. The occurrence of this G-6-PD Mediterranean type variant
in the Finnish population, which differs greatly from Mediterranean ethnic
groups, as well as the association of slight chronic haemolysis with severe
G-6-PD deficiency is discussed. Five hundred members belonging to the Bania community of Punjab were screened
for erythrocytic glucose-6-phosphate dehydrogenase (G-6-PD) deficiency. The
incidence of enzyme deficiency in males was 2.84 per cent and in females 2.75
per cent, with an overall incidence of 2.80 per cent. No correlation between age
and G-6-PD deficiency was found. The mean values for haemoglobin and haematocrit
did not differ significantly in the normal and deficient subjects. Study of the
deficiency pattern amongst family members of the enzyme deficient subjects
confirmed the X-linked inheritance of G-6-PD deficiency. This is a report about a 9 year old turkish boy suffering from recurrent
episodes of high fever caused by Plasmodium vivax-infection (Malaria tertiana),
12 months after returning from his malarious homeland. After a 3-day course of
Chloroquin, we administrated Primaquin to eliminate residual extraerythrocyte
forms of Plasmodium vivax. On the 7th day of treatment acute haemolysis
developped. This was caused by Glucose-6-Phosphate-Dehydrogenase-Deficiency,
which could be demonstrated by a red-cell-enzyme analysis. The investigation of
the patient's whole family showed the typical recessive X-linked inheritance of
this enzyme-defect. Frequency and clinical manifestations of this defect are
discussed. Glucose 6-phosphate dehydrogenase (G6PD) is a cytosolic enzyme encoded by a
housekeeping X-linked gene whose main function is to produce NADPH, a key
electron donor in the defense against oxidizing agents and in reductive
biosynthetic reactions. Inherited G6PD deficiency is associated with either
episodic hemolytic anemia (triggered by fava beans or other agents) or life-long
hemolytic anemia. We show here that an evolutionary analysis is a key to
understanding the biology of a housekeeping gene. From the alignment of the
amino acid (aa) sequence of 52 glucose 6-phosphate dehydrogenase (G6PD) species
from 42 different organisms, we found a striking correlation between the aa
replacements that cause G6PD deficiency in humans and the sequence conservation
of G6PD: two-thirds of such replacements are in highly and moderately conserved
(50-99%) aa; relatively few are in fully conserved aa (where they might be
lethal) or in poorly conserved aa, where presumably they simply would not cause
G6PD deficiency. This is consistent with the notion that all human mutants have
residual enzyme activity and that null mutations are lethal at some stage of
development. Comparing the distribution of mutations in a human housekeeping
gene with evolutionary conservation is a useful tool for pinpointing amino acid
residues important for the stability or the function of the corresponding
protein. In view of the current explosive increase in full genome sequencing
projects, this tool will become rapidly available for numerous other genes. Glucosephosphate isomerase (GPI) deficiency in humans is an autosomal recessive
disorder, which results in nonspherocytic hemolytic anemia of variable clinical
expression. A 4-year-old female with severe congenital hemolytic anemia had low
red cell GPI activity of 15.5 IU/g Hb (50% of normal mean) indicating GPI
deficiency. Subsequent DNA sequence analysis revealed a novel homozygous 921C to
G mutation in the GPI gene sequence, predicting a Phe307 to Leu replacement.
Strikingly, the red cell GPI activity in this patient was higher than that found
in a second patient expressing the same GPI variant, with a more severe clinical
phenotype. We propose that the hemolysis in the first patient may be modified by
an accompanying deficiency of glucose-6-phosphate dehydrogenase (G6PD). The
proband's red cell G6PD activity was reduced at 4.5 IU/g Hb (50% of normal mean)
and molecular studies revealed heterozygosity for the G6PD Viangchan mutation
and a skewed pattern of X-chromosome inactivation, producing almost exclusive
expression of the mutated allele. The G6PD Viangchan variant is characterised by
severe enzyme deficiency, but not chronic hemolysis. This study suggests that
the metabolic consequences of a combined deficiency of GPI and G6PD might be
responsible for a different clinical outcome than predicted for either defect in
isolation. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the commonest red cell
enzymopathy in humans and has an X-linked inheritance. It has been reported from
India more than 30 years ago and the prevalence varies from 0-27% in different
caste, ethnic and linguistic groups. The major clinical manifestations are drug
induced hemolytic anemia, neonatal jaundice and chronic non-spherocytic
hemolytic anemia. Individuals with G6PD deficiency have a selective advantage
against falciparum malaria. Thirteen biochemically characterized variants have
been reported from India. At the molecular level, G6PD Mediterranean is the most
common deficient variant in the caste groups whereas, G6PD Orissa is more
prevalent among the tribal of India. The third common variant seen in India is
G6PD Kerala-Kalyan. Glucose-6-Phosphate Dehydrogenase (G6PD) gene is located at the X-chromosome at
Xq28 and the disease is recessively inherited predomitly in males. More than
400 variants have been proposed based on clinical and enzymatic studies. The aim
of the current study was to identify C563T mutation in G6PD-deficient newborns
and to correlate the enzyme residual activity with the presence of the mutation.
Some 1189 full-term neonates aged 3-5 days old were tested for G6PD activity in
dried blood spots from Guthrie cards using a commercial kit. DNA extraction from
Guthrie cards and mutation identification among the deficient samples were
performed with current techniques. A total of 92 (7.7%) newborns were
G6PD-deficient. In 46 (50%), the mutation C563T was identified. The residual
activity in C563T hemizygote males (n = 28) was statistically significantly
lower (1.23 ± 0.93 U/g Hb) than that in non-C563T G6PD-deficient males (n = 25)
(4.01 ± 1.20 U/g Hb, p < 0.0001) and in controls (13.6 ± 2.9 U/g Hb, p <
0.0001). In C563T heterozygote females, the estimated enzyme activity was lower
than that determined in non-C563T females. Male C563T hemizygotes suffer from
G6PD deficiency and severe neonatal jaundice. G6PD activity showed statistically
significant correlation with total bilirubin blood levels. BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) is a metabolic enzyme
involved in the pentose phosphate pathway, its especially important in red blood
cell metabolism. Glucose-6-phosphate dehydrogenase deficiency is an X-linked
recessive hereditary disease characterised by abnormally low levels of G6PD.
About 400 million people worldwide have a deficiency of this enzyme. The
remarkable geographic correlation of G6PD deficiency distribution with
historical endemicity patterns of malaria has led to suggestions that the two
could be linked. Some studies have concluded that G6PD deficiency confers
resistance to malaria.
OBJECTIVE: To determine the prevalence of G6PD deficiency, and determine its
relationship with prevalence and incidence of P. falciparum infection among
children in Uganda.
METHODS: This was longitudinal study involving 245 children, 135 were actively
followed up for 12 months. G6PD status was assessed for using PCR-RFLP method. A
thick smear was done to determine presence of plasmodium trophozoites and
parasite densities.
RESULTS: A total of 245 children between 6 months and 9 years were recruited. Of
these 46.5% were males. Overall prevalence for the X-linked G6PD A- mutation
was; 79.59% wild type, 12.65% heterozygous and 7.76% homozygous or hemizygous.
Among the males 14% were hemizygous. At baseline, 40.8% had asymptomatic P
falciparum infection. There was no statistically significant difference in
prevalence and incidence rates of malaria infection among the different G6PD
genotypes with prevalence among heterozygous, homozygous, and wild type being
29%, 42.6% and 43% respectively (p = 0.11) and incidence among heterozygous and
wild type being 0.56 and 0.52 episodes/year (p = 0.5). The heterozygous G6PD A-
females had a lower parasite density compared to the wild type (2505 vs 941
parasites/μL; P = 0.024).
CONCLUSIONS: This study showed that 20.41% of the population in this part of
Uganda carry the G6PD A-mutation, within the range of 15-32% seen in other parts
of Africa. P. falciparum infection incidence and prevalence rates are similar
among the G6PD genotypes though, once infected, P. falciparum parasite densities
are lowest among G6PD A- heterozygous females. This suggests differences in P.
falciparum infection rates and severity of disease could be mediated by
differences in parasite densities among the different G6PD genotypes. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive
genetic defect that can cause hemolytic crisis. However, this disease affects
both males and females. In Turkey, the frequency of this enzyme deficiency was
reported to vary, from 0.25 to 18%, by the geographical area. Its prevalence in
the northern Black Sea region of Turkey is unknown. The aims of this study were
to assess the prevalence of G6PD deficiency in the northern region Turkey in
children and adults with hyperbilirubinemia and hemolytic anemia. This report
included a total of 976 G6PD enzyme results that were analyzed between May 2005
and January 2014. G6PD deficiency was detected in 5.0% of all patients. G6PD
deficiency was significantly less frequent in females (1.9%, 6/323) than in
males (6.6%, 43/653). G6PD deficiency was detected in 3.7% of infants with
hyperbilirubinemia, 9.2% of children, and 4.5% of adults with hemolytic anemia.
In both the newborn group and the group of children, G6PD deficiency was
significantly more frequent in males. In the combined group of children (groups
I and II), the proportion of males was 74% and 67% in all groups (P = .0008). In
conclusion, in northern region of Turkey, G6PD deficiency is an important cause
of neonatal hyperbilirubinemia and hemolytic crisis in children and adults. This
study suggests that most pediatricians thought that G6PD deficiency is
exclusively a male disease. For this reason, some female patients may have been
undiagnosed. Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive
hemolytic anemia caused by a mutation in the G6PD gene on Xq28. Herein, we
describe a Korean boy with G6PD deficiency resulting from a novel mutation in
G6PD. A 20-month-old boy with hemolytic anemia was referred for molecular
diagnosis. He had no relevant family history. The G6PD activity was severely
decreased at 0.2 U/g Hb (severe deficiency). Direct sequencing analyses on the
G6PD gene revealed that he was hemizygous for a novel missense variant,
c.1187C>G (p.Pro396Arg), in exon 10 of G6PD. Family study involving his parents
revealed the de novo occurrence of the mutation. This is the first report of
genetically confirmed G6PD deficiency in Korea. |
Which deep learning-based algorithms are used for enhancer prediction? | EP-DNN and DEEP. | Transcription regulation in multicellular eukaryotes is orchestrated by a number
of DNA functional elements located at gene regulatory regions. Some regulatory
regions (e.g. enhancers) are located far away from the gene they affect.
Identification of distal regulatory elements is a challenge for the
bioinformatics research. Although existing methodologies increased the number of
computationally predicted enhancers, performance inconsistency of computational
models across different cell-lines, class imbalance within the learning sets and
ad hoc rules for selecting enhancer candidates for supervised learning, are some
key questions that require further examination. In this study we developed DEEP,
a novel ensemble prediction framework. DEEP integrates three components with
diverse characteristics that streamline the analysis of enhancer's properties in
a great variety of cellular conditions. In our method we train many individual
classification models that we combine to classify DNA regions as enhancers or
non-enhancers. DEEP uses features derived from histone modification marks or
attributes coming from sequence characteristics. Experimental results indicate
that DEEP performs better than four state-of-the-art methods on the ENCODE data.
We report the first computational enhancer prediction results on FANTOM5 data
where DEEP achieves 90.2% accuracy and 90% geometric mean (GM) of specificity
and sensitivity across 36 different tissues. We further present results derived
using in vivo-derived enhancer data from VISTA database. DEEP-VISTA, when tested
on an independent test set, achieved GM of 80.1% and accuracy of 89.64%. DEEP
framework is publicly available at http://cbrc.kaust.edu.sa/deep/. Accurate identification of DNA regulatory elements becomes an urgent need in the
post-genomic era. Recent genome-wide chromatin states mapping efforts revealed
that DNA elements are associated with characteristic chromatin modification
signatures, based on which several approaches have been developed to predict
transcriptional enhancers. However, their practical application is limited by
incomplete extraction of chromatin features and model inconsistency for
predicting enhancers across different cell types. To address these issues, we
define a set of non-redundant shape features of histone modifications, which
shows high consistency across cell types and can greatly reduce the
dimensionality of feature vectors. Integrating shape features with a
machine-learning algorithm AdaBoost, we developed an enhancer predicting method,
DELTA (Distal Enhancer Locating Tool based on AdaBoost). We show that DELTA
significantly outperforms current enhancer prediction methods in prediction
accuracy on different datasets and can predict enhancers in one cell type using
models trained in other cell types without loss of accuracy. Overall, our study
presents a novel framework for accurately identifying enhancers from epigenetic
data across multiple cell types. Transcriptional enhancers are non-coding segments of DNA that play a central
role in the spatiotemporal regulation of gene expression programs. However,
systematically and precisely predicting enhancers remain a major challenge.
Although existing methods have achieved some success in enhancer prediction,
they still suffer from many issues. We developed a deep learning-based
algorithmic framework named PEDLA (https://github.com/wenjiegroup/PEDLA), which
can directly learn an enhancer predictor from massively heterogeneous data and
generalize in ways that are mostly consistent across various cell types/tissues.
We first trained PEDLA with 1,114-dimensional heterogeneous features in H1
cells, and demonstrated that PEDLA framework integrates diverse heterogeneous
features and gives state-of-the-art performance relative to five existing
methods for enhancer prediction. We further extended PEDLA to iteratively learn
from 22 training cell types/tissues. Our results showed that PEDLA manifested
superior performance consistency in both training and independent test sets. On
average, PEDLA achieved 95.0% accuracy and a 96.8% geometric mean (GM) of
sensitivity and specificity across 22 training cell types/tissues, as well as
95.7% accuracy and a 96.8% GM across 20 independent test cell types/tissues.
Together, our work illustrates the power of harnessing state-of-the-art deep
learning techniques to consistently identify regulatory elements at a
genome-wide scale from massively heterogeneous data across diverse cell
types/tissues. We present EP-DNN, a protocol for predicting enhancers based on chromatin
features, in different cell types. Specifically, we use a deep neural network
(DNN)-based architecture to extract enhancer signatures in a representative
human embryonic stem cell type (H1) and a differentiated lung cell type (IMR90).
We train EP-DNN using p300 binding sites, as enhancers, and TSS and random
non-DHS sites, as non-enhancers. We perform same-cell and cross-cell predictions
to quantify the validation rate and compare against two state-of-the-art
methods, DEEP-ENCODE and RFECS. We find that EP-DNN has superior accuracy with a
validation rate of 91.6%, relative to 85.3% for DEEP-ENCODE and 85.5% for RFECS,
for a given number of enhancer predictions and also scales better for a larger
number of enhancer predictions. Moreover, our H1 → IMR90 predictions turn out to
be more accurate than IMR90 → IMR90, potentially because H1 exhibits a richer
signature set and our EP-DNN model is expressive enough to extract these
subtleties. Our work shows how to leverage the full expressivity of deep
learning models, using multiple hidden layers, while avoiding overfitting on the
training data. We also lay the foundation for exploration of cross-cell enhancer
predictions, potentially reducing the need for expensive experimentation. |
Is Beta-Thalassemia is associated with a mutation or deletion of the gene that codes for alpha globin? | Beta-thalassemia, one of the most common single-gene disorders, is the result of reduced or absent production of β-globin chains | The beta-thalassemia syndromes are a heterogeneous group of genetic disorders
characterized by reduced or absent expression of the beta-globin gene. To date,
over 300 beta-thalassemia alleles have been characterized in or around the
beta-globin region. Thalassemia major is severe anemia necessitating chronic
blood transfusions, splenectomy, iron chelation therapy, and bone marrow
transplantation. Usually thalassemia major results from homozygosity or compound
heterozygosity for severe betaO- and/or beta+-thalassemia mutations. Thalassemia
intermedia is a clinical diagnosis that describes a symptomatic but less severe
condition than beta-thalassemia major. beta-thalassemia intermedia may arise
from several different combinations of alpha- and/or beta-thalassemia mutations.
Heterozygous beta-thalassemia is typically characterized by a mild microcytic
hypochromic anemia without any significant clinical implications. In this
report, we describe a 63-year-old Africian American woman with asymptomatic
homozygous beta-thalassemia, who seems to carry 2 copies of the -29 mutation in
the promoter region of the beta-globin gene. Her elevated hemoglobin F level of
83% was associated with heterozygosity for the Xmn I polymorphism upstream of
the Ggamma-globin gene. Southern blot analysis at the alpha-globin locus did not
show any deletion that would account for the mildness of her phenotype.
Therefore, homozygosity for the -29 mutation along with the Xmn I polymorphism
appears to confer an extremely mild beta-thalassemia phenotype. This observation
has important implications in the prenatal diagnosis and genetic counseling of
families segregating this type of genetic defect. Beta-thalassemia, one of the most common single-gene disorders, is the result of
reduced or absent production of β-globin chains. Patients with β-thalassemia
show weak genotype-phenotype correlations. Mitochondrial DNA polymorphisms are a
potential source for different physiological and pathological characteristics
and have been found to be associated as genetic modifiers with various
pathophysiologies, including cancers and neurodegenerative diseases. A group of
35 patients with β-thalassemia was investigated for the presence of mtDNA D-loop
polymorphisms in comparison with 504 normal controls. We found four mtDNA D-loop
polymorphisms at nucleotides 16,069C > T, 16,189T > C, 16,319G > A, and
16,519T > C that showed significant differences between patients and normal
subjects. There is no strong proof for the association of these polymorphisms
with β-thalassemia. It is hypothesized that iron overload or its effects on
sequestration of calcium or zinc can lead to oxidative stress and ROS production
inside the mitochondria. Therefore, possible accompanying of mtDNA polymorphisms
with β-thalassemia disease may complicate the genotype-phenotype correlation and
could affect the clinical outcomes in the patients. |
Is diphosphatidylglycerol (cardiolipin) a phospholipid of the mitochondrial membranes? | Yes, diphosphatidylglycerol (cardiolipin) is a phospholipid of the mitochondrial membranes. | Mitochondrial membranes reconstituted from lipid-depleted mitochondria and
aqueous phospholipid dispersions still have the phospholipid negative charges
available for ionic interaction with the basic protein, lysozyme. The
stoichiometry of the binding is of about 6 nmoles of lysozyme per 100 nmoles of
phospholipid in membranes reconstituted with Asolectin, and of 10 nmoles of
phospholipid phosphorus in membranes reconstituted with cardiolipin. Unextracted
submitochondrial particles ETP also bind lysozyme (about 3 nmoles per 100 nmoles
of phospholipid). These observations indicate that the phospholipid anionic
groups are not completely shielded by the mitochondrial proteins, which might
occupy areas between the nonpolar groups of the lipid molecules. 1. Mitochondria, inner and outer mitochondrial membranes and microsomes were
isolated and purified from pig heart. Their lipid composition and protein
components were studied. 2. The fatty acid distribution in the main
phospholipids seemed specific rather of a given phospholipid and not of one type
of membrane. 3. Inner mitochondrial membranes were characterized by a high
content in cardiolipin and a very low level of triglycerides together with a
high degree of unsaturation and C18 acids. Gel electrophoresis revealed 13
different polypeptide subunits of which 5 were major ranging in molecular
weights from 10000 to 215000. 4. In outer mitochondrial membranes, total lipid,
phosphatidylcholine, phosphatidylinositol, plasmologen and triglyceride contents
were much higher than in inner membranes. Fatty acids of phospholipids were
mostly saturated and the polypeptide pattern showed 12 components, of which 4
were major of mol. wt 75000, 60000, 20000 and below 10000. 5. Compared to outer
membrane, microsomes exhibited a much higher cholesterol content and markedly
different protein profiles. They contained significant amounts of cardiolipin
and phosphatidylserine, this latter phospholipid being exclusively located in
microsomes. However odd similarities were observed in some lipid components of
microsomes and inner mitochondrial membranes, but fatty acids were more
saturated in microsomes and electrophoretic profiles of protein components
appeared very different and revealed components of high mol. wt. The mechanism of cardiolipin (diphosphatidylglycerol) biosynthesis was examined
in mitochondria and outer and inner mitochondrial membranes prepared from guinea
pig and rat livers to determine whether this formation from phosphatidylglycerol
was absolutely dependent on cytidinediphosphodiglyceride, as previously reported
for intact mitochondria. Experimental results confirmed that the biosynthesis of
cardiolipin, from the membrane-bound radioactive phosphatidylglycerol in intact
mitochondria isolated from guinea pig and rat liver, was absolutely dependent on
CDP-diglycerides and required the addition of divalent cations. Furthermore, the
same mechanism for the biosynthesis of cardiolipin was operational in the outer
and inner mitochondrial membranes. This biosynthesis was associated with both
the outer and inner mitochondrial membranes prepared from guinea pig liver, but
only with the inner mitochondrial membranes prepared from rat liver. The release
of radioactive glycerol was also measured, but the amount obtained did not
satisfy the stoichiometric requirement for CDP-diglyceride-independent
biosynthesis of cardiolipin from 2 mol of phosphatidylglycerol with the
liberation of 1 mol of glycerol. Therefore, it was concluded that this mechanism
is not involved in the biosynthesis of cardiolipin in mitochondrial and
submitochondrial membranes prepared from guinea pig and rat liver. As is the case for the assembly of protein components of the membranes in animal
mitochondria, the bilayer phospholipids arise from a complicated interplay of
intra- and extra-mitochondrial reactions. Our early studies indicated that the
bulk of mitochondrial phospholipids (typified by phosphatidylcholine) had their
origin in the endoplasmic reticulum and were transported to the mitochondria as
complexes with phospholipid-exchange proteins. The polyglycerophosphatides
(typified by diphosphatidylglycerol) were apparently synthesized in situ by
intramitochondrial membrane-bound enzymes using CDP-diglycerides as
intermediates. The case for the precursors in the latter pathway is less clear,
although evidence has been presented for dual localization of enzymes for
glycerophosphate acylation and CTP:phosphatidate cytidylyl transfer in both
mitochondria and microsomes. Phosphatidylethanolamine also shows evidence for
two sites of origin: by translocation from its site of synthesis in the
endoplasmic reticulum and by translocation of phosphatidylserine followed by
decarboxylation within the mitochondria. In the latter case mitochondrial
phosphatidylserine decarboxylase may play an important role in the regulation of
phospholipid metabolism throughout the cell. Participation of microsomal CDP-diglycerides in mitochondrial biosynthesis of
phosphatidylglycerol was studied by [3H]palmitoyl, [14C]linoleoyl, and
[14C]arachidonoyl CDP-diglycerides and [3H]CDP-diglycerides which were bound to
microsomal membranes, incubated with unlabelled mitochondrial membranes, and
further incubated in the presence of radioactive sn-glycero-3-phosphate under
conditions required for mitochondrial phosphatidylglycerol biosynthesis. Ten to
15% of microsomal radioactive CDP-diglycerides was transferred to mitochondrial
membranes and incorporated into mitochondrial radioactive lipids identified as
phosphatidylglycerol, phosphatidylglycerophosphate, and, when [14C]linoleoyl
CDP-diglycerides were used, diphosphatidylglycerol (cardiolipin). Homogenates of the placental tissue of near term sheep were separated by
differential centrifugation into mitochondrial, microsomal and cytosolic
fractions. The relative proportions of the major neutral lipids and
phospholipids, together with their fatty acid compositions, were determined in
the homogenates and in each subcellular fraction. The cytosolic fraction
contained the highest proportion of cholesteryl esters (CEs) and these possessed
a fatty acid composition markedly different from the total CEs extracted from
the homogenate. Both the mitochondrial and microsomal fractions contained
significant proportions of solvent front phospholipid (SFP) and whereas the
mitochondrial SFP displayed the relatively unsaturated fatty acid composition
characteristic of diphosphatidylglycerol (cardiolipin), the fatty acids of the
microsomal SFP were distinctly more saturated. These results are compared with
those obtained from other mammalian tissues, both rumit and non-rumit, and
discussed in terms of the function of the components of the subcellular
fractions. Mitochondrial membranes were isolated from the myocardium of young (4-month-old)
and aged (33-month-old) male Long-Evans rats and compared in terms of
cholesterol content and phospholipid and fatty acid composition. In aged rats,
as compared to young, the major observations include: markedly higher
cholesterol content; increased percentage of sphingomyelin and
diphosphatidylglycerol (cardiolipin); in fatty acids, variable changes, with a
predomit increase in the 16:0 in most phospholipids except cardiolipin, and
sporadic increase in the longer chain (20:0, 24:0) fatty acids in cardiolipin;
decreased unsaturation index for most phospholipids but increased for
cardiolipin. These results are tentatively interpreted as indicative of an
aging-related decrease in fluidity and energy transduction of mitochondrial
membrane in the heart of aged rats and may be responsible, in part, for the
decrements in cardiac function with aging. Lipid changes in mitochondria isolated from rat kidney after various periods of
ischemia were analysed by thin-layer chromatography and gas-liquid
chromatography. Free fatty acids were increased at 30 min and more so
thereafter. Total phospholipid fatty acids decreased steadily. The proportion of
diphosphatidylglycerol (cardiolipin) in the total phospholipid fraction
decreased at 30 min, but the proportion of phosphatidylcholine and
phosphatidylethanolamine in the total phospholipid fraction did not change until
the irreversible phase of ischemic injury. We have shown that decrease of
cardiolipin in mitochondrial membrane occurs early during ischemia, and only
during the irreversible phase of ischemia are phosphatidylethanolamine and
phosphatidylcholine broken down. It is postulated that these phenomena are due
to activation of phospholipase in the mitochondrial membrane. The properties of the binding of annexin V to variously composed phospholipid
vesicles have been studied by applying a recently developed EPR method, using an
annexin V spin label. By this approach, this protein is seen to bind to acidic
phospholipid-containing vesicles, as reported, thus confirming the reliability
of the method. In addition, binding of this annexin to cardiolipin-containing
vesicles has been studied in more depth, and the protein has been shown to have
a distinct affinity for this phospholipid. As a cardiolipin-rich natural
membrane system, mitochondrial membranes and mitoplasts from rat liver were
considered, and a strong binding of AV to these membranes was observed. Having
compared this binding with that to phospholipid vesicles, cardiolipin-rich
microdomains in the mitochondrial membranes are proposed as the putative
mitochondrial binding sites for annexin V. The distribution of cardiolipin across the inner mitochondrial membrane was
directly determined by using the ability of the fluorescent dye
10-N-nonyl-3,6-bis(dimethylamino)acridine (10-N-nonyl acridine orange) to form
dimers when it interacts with the diacidic phospholipid. Two independent methods
were employed: (a) a spectrophotometric measurement of 10-N-nonyl acridine
orange binding to isolated rat liver mitochondria, mitoplasts and inside-out
submitochondrial particles, and (b) a flow-cytometric analysis of specific red
fluorescence, emitted when two dye molecules are bound to one membrane
cardiolipin; the stoichiometry of 10-N-nonyl acridine orange binding to
phosphatidylserine and phosphatidylinositol, 1 mol dye/mol phospholipid,
prevented dye dimerisation and subsequent red-fluorescence appearance. 57% total
cardiolipin was present in the outer leaflets of inner membranes of isolated
organelles, a distribution confirmed by saturation measurements for mitoplasts
and inside-out submitochondrial particles. The same asymmetry was directly
observed in situ with mitochondrial membranes of quiescent L1210 cells, and with
mitochondrial membranes of respiring yeasts. Nevertheless, alterations in ATP
synthesis and inhibition of mitochondrial protein synthesis revealed that
cardiolipin distribution was apparently tightly correlated with mitochondrial
membrane assembly and activity. Sycamore suspension cells (Acer pseudoplatanus L.) were grown in the presence of
sublethal concentrations of copper (50 microM). During the first 5-6 days of
treatment, growth was not affected, but cell respiration (coupled and uncoupled)
declined to approximately 60% of its normal value. This decline of respiration
was attributed to a progressive diminution of the number of mitochondria in
copper-treated cells, based on the demonstration of the concomitant decline of
(1) cardiolipin (diphosphatidylglycerol) and cytochrome aa3 (cytochrome
oxidase), two specific markers of mitochondrial inner membrane, and (2) fumarase
activity, a specific marker of mitochondrial matrix space. In addition, the
mitochondria extracted from copper-treated cells presented the same properties
as those from control cells, concerning substrate oxidation, cardiolipin and
cytochrome aa3 contents, and fumarase activity. These results strongly suggest
that copper triggered an arrest of mitochondrial biogenesis, which preceded cell
division arrest. The phospholipid cardiolipin, or diphosphatidylglycerol, is ubiquitous in
eucaryotes. It is unique in structure, subcellular localization, and potential
function. Because it is found predomitly in the mitochondrial inner membrane,
it is an excellent marker for mitochondrial biogenesis. Cardiolipin is required
for activity of several mitochondrial enzymes and possibly also for import of
proteins into the mitochondrion. To understand the role of cardiolipin in these
cellular events, it is necessary to characterize the enzymes of the cardiolipin
pathway, as well as the genes that control the expression of these enzymes. To
date, the structural genes encoding the cardiolipin biosynthetic enzymes have
not been identified in any eucaryotic organism. However, considerable
information is available regarding the regulation of this pathway in yeast. The
activity and regulation of the first enzyme of the pathway,
CDP-diacylglycerol:sn-glycerol-3-phosphate 3-phosphatidyltransferase
(phosphatidylglycerophosphate (PGP) synthase, EC 2.7.8.5), has been
characterized in two evolutionarily divergent yeasts, Saccharomyces cerevisiae
and Schizosaccharomyces pombe. In contrast to the second and third enzymes of
the pathway, this enzyme is highly regulated, both by cross-pathway control and
by factors affecting mitochondrial development. PGP synthase from S. pombe (and
cardiolipin synthase from S. cerevisiae) have been purified to homogeneity. The
amino acid sequences of these enzymes, combined with the availability of the
complete genome sequence from S. cerevisiae will simplify the cloning of these
genes in the near future. The phospholipid and protein compositions of mitochondrial membranes from
hepatopancreas of active and estivating terrestrial snails (Cepaea nemoralis)
were compared. Mitochondria from estivating snails contained 82.7% less
cardiolipin, and this was associated with an 83.9% reduction in cytochrome-c
oxidase activity. Substantial changes also occurred in the proportional amounts
of other individual phospholipid classes and their constituent fatty acids,
including a 72% loss of total mitochondrial phospholipids, a 37% increase in
monoenes, and 49% fewer n-3 fatty acids in membranes of estivating snails. These
changes are consistent with those correlated with lowered metabolic rate and
lower rates of proton leak in other animal models. Estivating snail
hepatopancreas showed no change in total phospholipid content, indicating that
the phospholipids lost from mitochondrial membranes may be sequestered elsewhere
within the cell. We suggest that estivating snails remodel mitochondrial
membranes as part of a coordinated, reversible suppression of mitochondrial
membrane-associated processes, which may include a concomitant reduction in
rates of proton pumping and leaking. The fatty acid composition of phospholipids is an important determit of
membrane function. Although the mitochondria play a pivotal role in skeletal
muscle function, the fatty acid composition of their individual phospholipids
has not been examined. The purpose of this study was to determine the fatty acid
profile of each phospholipid in rat skeletal muscle mitochondria and compare it
with that of the whole muscle. Lipids were extracted from the gastrocnemius
muscles of 10 Wistar rats, and phospholipids were separated by thin-layer
chromatography. The fatty acid composition of each phospholipid was then
determined by gas chromatography. The same procedure was applied to a
mitochondrial preparation from these muscles. We found that the fatty acid
composition of the individual mitochondrial phospholipids (phosphatidyl choline,
phosphatidyl ethanolamine, cardiolipin, phosphatidyl inositol, phosphatidyl
serine, sphingomyelin, and lysophosphatidyl choline) and of the total
mitochondrial phospholipids differed markedly (P < 0.05) from the fatty acid
composition of the corresponding whole muscle phospholipids. Notably, the
mitochondrial phospholipids had higher percentages of MUFA [13.9 (2.1) vs. 10.3
(0.9)] and lower percentages of PUFA [34.8 (4.3) vs. 39.5 (5.2)] and n6 fatty
acids [25.0 (2.5) vs. 27.6 (2.5)]. Overall, the mitochondrial phospholipids had
a lower unsaturation index than whole muscle phospholipids [135 (20) vs. 161
(26)]. Because PUFA are susceptible to peroxidation, unlike saturated fatty
acids and MUFA, we propose that the low polyunsaturation of mitochondrial
phospholipids is the result of selective pressure toward membranes that are more
resistant to oxidative damage by reactive oxygen species produced in their
vicinity. The negative effect of the low polyunsaturation on membrane fluidity
may be counterbalanced by the higher percentage of MUFA and the known low
cholesterol content of mitochondrial membranes. The phospholipid composition of membranes can influence the physiological
functioning of the cell or subcellular organelle. This association has been
previously demonstrated in skeletal muscle, where cellular or subcellular
membrane, specifically mitochondria, phospholipid composition is linked to
muscle function. However, these observations are based on whole mixed skeletal
muscle analysis, with little information on skeletal muscles of differing
fiber-type compositions. These past approaches that used mixed muscle may have
misidentified outcomes or masked differences. Thus, the purpose of this study
was to compare the phospholipid fatty acid composition of subsarcolemmal (SS)
mitochondria isolated from slow-twitch postural (soleus), fast-twitch highly
oxidative glycolytic locomotory (red gastrocnemius), and fast-twitch oxidative
glycolytic locomotory (plantaris) skeletal muscles. The main findings of the
study demonstrated unique differences between SS mitochondrial membranes from
postural soleus compared to the other locomotory skeletal muscles examined,
specifically lower percentage mole fraction of phosphatidylcholine (PC) and
significantly higher percentage mole fraction of saturated fatty acids (SFA) and
lower n6 polyunsaturated fatty acids (PUFA), resulting in a lower unsaturation
index. We also found that although there was no difference in the percentage
mole fraction of cardiolipin (CL) between skeletal muscle types examined, CL of
soleus mitochondrial membranes were approximately twofold more SFA and
approximately two-thirds less PUFA, resulting in a 20-30% lower unsaturation and
peroxidation indices. Thus, the results of this study indicate unique membrane
lipid composition of mitochondria isolated from different skeletal muscle types,
a potential consequence of their respective duty cycles. Late embryogenesis abundant (LEA) proteins are a highly diverse group of
polypeptides expected to play important roles in desiccation tolerance of plant
seeds. They are also found in other plant tissues and in some anhydrobotic
invertebrates, fungi, protists and prokaryotes. The LEA protein LEAM accumulates
in the matrix space of pea (Pisum sativum) mitochondria during late seed
maturation. LEAM is an intrinsically disordered protein folding into amphipathic
alpha-helix upon desiccation. This suggests that it could interact with the
inner mitochondrial membrane, providing structural protection in dry seeds.
Here, we have used Fourier-transform infrared and fluorescence spectroscopy to
gain insight into the molecular details of interactions of LEAM with
phospholipid bilayers in the dry state and their effects on liposome stability.
LEAM interacted specifically with negatively charged phosphate groups in dry
phospholipids, increasing fatty acyl chain mobility. This led to an enhanced
stability of liposomes during drying and rehydration, but also upon freezing.
Protection depended on phospholipid composition and was strongly enhanced in
membranes containing the mitochondrial phospholipid cardiolipin. Collectively,
the results provide strong evidence for a function of LEAM as a mitochondrial
membrane protectant during desiccation and highlight the role of lipid
composition in the interactions between LEA proteins and membranes. Membrane composition, particularly of mitochondria, could be a critical factor
by determining the propagation of reactions involved in mitochondrial function
during periods of high oxidative stress such as rapid growth and aging.
Considering that phospholipids not only contribute to the structural and
physical properties of biological membranes, but also participate actively in
cell signaling and apoptosis, changes affecting either class or fatty acid
compositions could affect phospholipid properties and, thus, alter mitochondrial
function and cell viability. In the present study, heart and brain mitochondrial
membrane phospholipid compositions were analyzed in rainbow trout during the
four first years of life, a period characterized by rapid growth and a sustained
high metabolic rate. Specifically, farmed fish of three ages (1-, 2- and
4-years) were studied, and phospholipid class compositions of heart and brain
mitochondria, and fatty acid compositions of individual phospholipid classes
were determined. Rainbow trout heart and brain mitochondria showed different
phospholipid compositions (class and fatty acid), likely related to
tissue-specific functions. Furthermore, changes in phospholipid class and fatty
acid compositions with age were also tissue-dependent. Heart mitochondria had
lower proportions of cardiolipin (CL), phosphatidylserine (PS) and
phosphatidylinositol, and higher levels of phosphatidylcholine (PC) and
phosphatidylethanolamine (PE) with age. Heart mitochondrial membranes became
more unsaturated with age, with a significative increase of peroxidation index
in CL, PS and sphingomyelin (SM). Therefore, heart mitochondria became more
susceptible to oxidative damage with age. In contrast, brain mitochondrial PC
and PS content decreased in 4-year-old animals while there was an increase in
the proportion of SM. The three main phospholipid classes in brain (PC, PE and
PS) showed decreased n-3 polyunsaturated fatty acids, docosahexaenoic acid and
peroxidation index, which indicate a different response of brain mitochondrial
lipids to rapid growth and maturation. Cardiolipin, the specific phospholipid of mitochondria, is involved in the
biogenesis, the dynamics, and the supramolecular organization of mitochondrial
membranes. Cardiolipin acquires a characteristic composition of fatty acids by
post-synthetic remodeling, a process that is crucial for cardiolipin homeostasis
and function. The remodeling of cardiolipin depends on the activity of tafazzin,
a non-specific phospholipid-lysophospholipid transacylase. This review article
discusses recent findings that suggest a novel function of tafazzin in
mitochondrial membranes. By shuffling fatty acids between molecular species,
tafazzin transforms the lipid composition and by doing so supports changes in
the membrane conformation, specifically the generation of membrane curvature.
Tafazzin activity is critical for the differentiation of cardiomyocytes, in
which the characteristic cristae-rich morphology of cardiac mitochondria
evolves. This article is part of a Special Issue entitled Phospholipids and
Phospholipid Metabolism. A unique organelle for studying membrane biochemistry is the mitochondrion whose
functionality depends on a coordinated supply of proteins and lipids.
Mitochondria are capable of synthesizing several lipids autonomously such as
phosphatidylglycerol, cardiolipin and in part phosphatidylethanolamine,
phosphatidic acid and CDP-diacylglycerol. Other mitochondrial membrane lipids
such as phosphatidylcholine, phosphatidylserine, phosphatidylinositol, sterols
and sphingolipids have to be imported. The mitochondrial lipid composition, the
biosynthesis and the import of mitochondrial lipids as well as the regulation of
these processes will be main issues of this review article. Furthermore,
interactions of lipids and mitochondrial proteins which are highly important for
various mitochondrial processes will be discussed. Malfunction or loss of
enzymes involved in mitochondrial phospholipid biosynthesis lead to dysfunction
of cell respiration, affect the assembly and stability of the mitochondrial
protein import machinery and cause abnormal mitochondrial morphology or even
lethality. Molecular aspects of these processes as well as diseases related to
defects in the formation of mitochondrial membranes will be described. Mitochondria are essential and dynamic organelles in eukaryotes. Cardiolipin
(CL) is a key phospholipid in mitochondrial membranes, playing important roles
in maintaining the functional integrity and dynamics of mitochondria in animals
and yeasts. However, CL's role in plants is just beginning to be elucidated. In
this study, we used Arabidopsis thaliana to examine the subcellular distribution
of CL and CARDIOLIPIN SYNTHASE (CLS) and analyzed loss-of-function cls mutants
for defects in mitochondrial morphogenesis and stress response. We show that CL
localizes to mitochondria and is enriched at specific domains, and CLS targets
to the inner membrane of mitochondria with its C terminus in the intermembrane
space. Furthermore, cls mutants exhibit significantly impaired growth as well as
altered structural integrity and morphogenesis of mitochondria. In contrast to
animals and yeasts, in which CL's effect on mitochondrial fusion is more
profound, Arabidopsis CL plays a domit role in mitochondrial fission and
exerts this function, at least in part, through stabilizing the protein complex
of the major mitochondrial fission factor, DYNAMIN-RELATED PROTEIN3. CL also
plays a role in plant responses to heat and extended darkness, stresses that
induce programmed cell death. Our study has uncovered conserved and
plant-specific aspects of CL biology in mitochondrial dynamics and the organism
response to environmental stresses. It is essential to understand the role of cardiolipin (CL) in mitochondrial
membrane organization given that changes in CL levels contribute to
mitochondrial dysfunction in type II diabetes, ischemia-reperfusion injury,
heart failure, breast cancer, and aging. Specifically, there are contradictory
data on how CL influences the molecular packing of membrane phospholipids.
Therefore, we determined how increasing levels of heart CL impacted molecular
packing in large unilamellar vesicles, modeling heterogeneous lipid mixtures
found within the mitochondrial inner membrane, using merocyanine (MC540)
fluorescence. We broadly categorized lipid vesicles of equal mass as loosely
packed, intermediate, and highly packed based on peak MC540 fluorescence
intensity. CL had opposite effects on loosely versus highly packed vesicles.
Exposure of loosely packed vesicles to increasing levels of CL dose-dependently
increased membrane packing. In contrast, increasing amounts of CL in highly
packed vesicles decreased the packing in a dose-dependent manner. In vesicles
that were categorized as intermediate packing, CL had either no effect or
decreased packing at select doses in a dose-independent manner. Altogether, the
results aid in resolving some of the discrepant data by demonstrating that CL
displays differential effects on membrane packing depending on the composition
of the lipid environment. This has implications for mitochondrial protein
activity in response to changing CL levels in microdomains of varying
composition. Brain mitochondria are fundamental to maintaining healthy functional brains, and
their dysfunction is involved in age-related neurodegenerative disorders such as
Alzheimer's disease (AD). In this study, we conducted a research on how both
non-synaptic and synaptic mitochondrial functions are compromised at an early
stage of AD-like pathologies and their correlation with putative changes on
membranes lipid profile, using 3 month-old nontransgenic and 3xTg-AD mice, a
murine model of experimental AD. Bioenergetic dysfunction in 3xTg-AD brains is
evidenced by a decrease of brain ATP levels resulting, essentially, from
synaptic mitochondria functionality disruption as indicated by declined
respiratory control ratio associated with a 50% decreased complex I activity.
Lipidomics studies revealed that synaptic bioenergetic deficit of 3xTg-AD brains
is accompanied by alterations in the phospholipid composition of synaptic
mitochondrial membranes, detected either in phospholipid class distribution or
in the phospholipids molecular profile. Globally, diacyl- and
lyso-phosphatidylcholine lipids increase while ethanolamine plasmalogens and
cardiolipins content drops in relation to nontransgenic background. However, the
main lipidomic mark of 3xTg-AD brains is that cardiolipin cluster-organized
profile is lost in synaptic mitochondria due to a decline of the most
representative molecular species. In contrast to synaptic mitochondria, results
support the idea that non-synaptic mitochondria function is preserved at the age
of 3 months. Although the genetically construed 3xTg-AD mouse model does not
represent the most prevalent form of AD in humans, the present study provides
insights into the earliest biochemical events in AD brain, connecting specific
lipidomic changes with synaptic bioenergetic deficit that may contribute to the
progressive synapses loss and the neurodegenerative process that characterizes
AD. Mitochondria play a key role in adaptation during stressing situations.
Cardiolipin, the main anionic phospholipid in mitochondrial membranes, is
expected to be a determit in this adaptive mechanism since it modulates the
activity of most membrane proteins. Here, we used Saccharomyces cerevisiae
subjected to conditions that affect mitochondrial metabolism as a model to
determine the possible role of cardiolipin in stress adaptation. Interestingly,
we found that thermal stress promotes a 30% increase in the cardiolipin content
and modifies the physical state of mitochondrial membranes. These changes have
effects on mtDNA stability, adapting cells to thermal stress. Conversely, this
effect is cardiolipin-dependent since a cardiolipin synthase-null mutant strain
is unable to adapt to thermal stress as observed by a 60% increase of cells
lacking mtDNA (ρ0). Interestingly, we found that the loss of cardiolipin
specifically affects the segregation of mtDNA to daughter cells, leading to a
respiratory deficient phenotype after replication. We also provide evidence that
mtDNA physically interacts with cardiolipin both in S. cerevisiae and in
mammalian mitochondria. Overall, our results demonstrate that the mitochondrial
lipid cardiolipin is a key determit in the maintece of mtDNA stability and
segregation. Cardiolipin (CL), a unique mitochondrial phospholipid, plays a key role in
several processes of mitochondrial bioenergetics as well as in mitochondrial
membrane stability and dynamics. The present study was designed to determine the
effect of MitoQ, a mitochondrial-targeted antioxidant, on the content of liver
mitochondrial membrane phospholipids, in particular CL, and its fatty acid
composition in obesogenic diet-fed rats. To do this, twenty-four 6week old male
Sprague Dawley rats were randomized into three groups of 8 animals and fed for
8weeks with either a control diet, a high fat diet (HF), or a HF diet with MitoQ
(HF+MitoQ). Phospholipid classes and fatty acid composition were assayed by
chromatographic methods in liver and liver mitochondria. Mitochondrial
bioenergetic function was also evaluated. While MitoQ had no or slight effects
on total liver fatty acid composition and phospholipid classes and their fatty
acid composition, it had major effects on liver mitochondrial phospholipids and
mitochondrial function. Indeed, MitoQ both increased CL synthase gene expression
and CL content of liver mitochondria and increased 18:2n-6 (linoleic acid)
content of mitochondrial phospholipids by comparison to the HF diet. Moreover,
mitochondrial CL content was positively correlated to mitochondrial membrane
fluidity, membrane potential and respiration, as well as to ATP synthase
activity, while it was negatively correlated to mitochondrial ROS production.
These findings suggest that MitoQ may decrease pathogenic alterations to CL
content and profiles, thereby preserving mitochondrial function and attenuating
the development of some of the features of metabolic syndrome in obesogenic
diet-fed rats. Cardiolipin (CL), the signature phospholipid of mitochondrial membranes, is
crucial for both mitochondrial function and cellular processes outside of the
mitochondria. The importance of CL in cardiovascular health is underscored by
the life-threatening genetic disorder Barth syndrome (BTHS), which manifests
clinically as cardiomyopathy, skeletal myopathy, neutropenia, and growth
retardation. BTHS is caused by mutations in the gene encoding tafazzin, the
transacylase that carries out the second CL remodeling step. In addition to
BTHS, CL is linked to other cardiovascular diseases (CVDs), including
cardiomyopathy, atherosclerosis, myocardial ischemia-reperfusion injury, heart
failure, and Tangier disease. The link between CL and CVD may possibly be
explained by the physiological roles of CL in pathways that are
cardioprotective, including mitochondrial bioenergetics, autophagy/mitophagy,
and mitogen activated protein kinase (MAPK) pathways. In this review, we focus
on the role of CL in the pathogenesis of CVD as well as the molecular mechanisms
that may link CL functions to cardiovascular health. Author information:
(1)Center for Free Radical and Antioxidant Health, Department of Environmental
and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
[email protected] [email protected] [email protected].
(2)Division of Molecular Toxicology, Institute of Environmental Medicine,
Karolinska Institutet, Stockholm 171 77, Sweden.
(3)Division of Pulmonary, Allergy and Critical Care Medicine, Department of
Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213,
USA.
(4)Center for Free Radical and Antioxidant Health, Department of Environmental
and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
(5)Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261,
USA.
(6)Division of Metabolic and Vascular Health, University of Warwick, Coventry
CV4 7AL, UK.
(7)Department of Internal Medicine, Acute Lung Injury Center of Excellence,
University of Pittsburgh, Pittsburgh, PA 15213, USA. Veterans Affairs Pittsburgh
Healthcare System, Pittsburgh, PA 15215, USA.
(8)Center for Free Radical and Antioxidant Health, Department of Environmental
and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15219, USA.
Department of Critical Care Medicine, University of Pittsburgh School of
Medicine, Pittsburgh, PA 15261, USA.
(9)Division of Molecular Toxicology, Institute of Environmental Medicine,
Karolinska Institutet, Stockholm 171 77, Sweden. [email protected]
[email protected] [email protected]. |
Have studies shown that there is no link between DNA methylation patterns and Post Traumatic Stress Disorder? | Studies do show a correlation of PTSD-related accelerated aging in DNA methylation patterns. | Post-traumatic stress disorder (PTSD) is unique among psychiatric disorders
since there is an explicit requirement for the presence of a well-defined
precipitating environmental event. This suggests the participation of adaptable
molecular processes such as epigenetic modifications, including acetylation and
methylation of histones and DNA methylation. In the present study we
investigated whether changes in DNA methylation are associated with the effects
of traumatic stressor, using a validated PTSD rat model. Screening of genomic
DNA methylation patterns revealed that maladaptation to traumatic stress is
associated with numerous changes in the methylation pattern of rat hippocampus.
Of the differentially methylated genes revealed by this global screening, Disks
Large-Associated Protein (Dlgap2) was of special interest, demonstrating an
increase in a specific methylation site which was associated with a reduction in
its gene expression in PTSD-like compared to non-PTSD-like rats. The association
between the methylation rate and Dlgap2 expression was further substantiated by
re-dividing the rats according to their methylation state. A significantly
higher expression was observed in the non-methylated compared to methylated
rats. In addition, taking all rats as one group revealed a significant
correlation between their behavioural stress responses and Dlgap2 transcript
levels. These results suggest that alterations in global methylation pattern are
involved in behavioural adaptation to environmental stress and pinpoint Dlgap2
as a possible target in PTSD. Epigenetic alterations of the brain-derived neurotrophic factor (Bdnf) gene have
been linked with memory, stress, and neuropsychiatric disorders. Here we
examined whether there was a link between an established rat model of
post-traumatic stress disorder (PTSD) and Bdnf DNA methylation. Adult male
Sprague-Dawley rats were given psychosocial stress composed of two acute cat
exposures in conjunction with 31 days of daily social instability. These
manipulations have been shown previously to produce physiological and behavioral
sequelae in rats that are comparable to symptoms observed in traumatized people
with PTSD. We then assessed Bdnf DNA methylation patterns (at exon IV) and gene
expression. We have found here that the psychosocial stress regimen
significantly increased Bdnf DNA methylation in the dorsal hippocampus, with the
most robust hypermethylation detected in the dorsal CA1 subregion. Conversely,
the psychosocial stress regimen significantly decreased methylation in the
ventral hippocampus (CA3). No changes in Bdnf DNA methylation were detected in
the medial prefrontal cortex or basolateral amygdala. In addition, there were
decreased levels of Bdnf mRNA in both the dorsal and ventral CA1. These results
provide evidence that traumatic stress occurring in adulthood can induce CNS
gene methylation, and specifically, support the hypothesis that epigenetic
marking of the Bdnf gene may underlie hippocampal dysfunction in response to
traumatic stress. Furthermore, this work provides support for the speculative
notion that altered hippocampal Bdnf DNA methylation is a cellular mechanism
underlying the persistent cognitive deficits which are prominent features of the
pathophysiology of PTSD. As potential regulators of DNA accessibility and activity, epigenetic
modifications offer a mechanism by which the environment can moderate the
effects of genes. To date, however, there have been relatively few studies
assessing epigenetic modifications associated with post-traumatic stress
disorder (PTSD). Here we investigate PTSD-associated methylation differences in
33 genes previously shown to differ in whole blood-derived gene expression
levels between those with vs. without the disorder. Drawing on DNA samples
similarly obtained from whole blood in 100 individuals, 23 with and 77 without
lifetime PTSD, we used methylation microarray data to assess whether these 33
candidate genes showed epigenetic signatures indicative of increased risk for,
or resilience to, PTSD. Logistic regression analyses were performed to assess
the main and interacting effects of candidate genes' methylation values and
number of potentially traumatic events (PTEs), adjusting for age and other
covariates. Results revealed that only one candidate gene - MAN2C1} - showed a
significant methylation x PTE interaction, such that those with both higher
MAN2C1 methylation and greater exposure to PTEs showed a marked increase in risk
of lifetime PTSD (OR 4.35, 95% CI: 1.07, 17.77, p=0.04). These results indicate
that MAN2C1 methylation levels modify cumulative traumatic burden on risk of
PTSD, and suggest that both gene expression and epigenetic changes at specific
loci are associated with this disorder. DNA methylation may mediate persistent changes in gene function following
chronic stress. To examine this hypothesis, we evaluated African American
subjects matched by age and sex, and stratified into four groups by
post-traumatic stress disorder (PTSD) diagnosis and history of child abuse.
Total Life Stress (TLS) was also assessed in all subjects. We evaluated DNA
extracted from peripheral blood using the HumanMethylation27 BeadChip and
analyzed both global and site-specific methylation. Methylation levels were
examined for association with PTSD, child abuse history, and TLS using a linear
mixed model adjusted for age, sex, and chip effects. Global methylation was
increased in subjects with PTSD. CpG sites in five genes (TPR, CLEC9A, APC5,
ANXA2, and TLR8) were differentially methylated in subjects with PTSD.
Additionally, a CpG site in NPFFR2 was associated with TLS after adjustment for
multiple testing. Notably, many of these genes have been previously associated
with inflammation. Given these results and reports of immune dysregulation
associated with trauma history, we compared plasma cytokine levels in these
subjects and found IL4, IL2, and TNFα levels associated with PTSD, child abuse,
and TLS. Together, these results suggest that psychosocial stress may alter
global and gene-specific DNA methylation patterns potentially associated with
peripheral immune dysregulation. Our results suggest the need for further
research on the role of DNA methylation in stress-related illnesses. AIM: We investigated serum DNA methylation patterns in genomic repetitive
elements, LINE-1 and Alu, for post-traumatic stress disorder (PTSD) cases and
controls who were US military service members recently deployed to Afghanistan
or Iraq.
METHODS: Cases (n = 75) had a postdeployment diagnosis of PTSD. Controls (n =
75) were randomly selected service members with no postdeployment PTSD
diagnosis. Pre- and post-deployment sera were accessed, DNA was extracted and
DNA methylation (percentage 5-methyl cytosine) was quantified via
pyrosequencing. Conditional and unconditional logistic regressions were used to
compare: cases post- to pre-deployment; controls post- to pre-deployment; cases
to controls predeployment; cases to controls postdeployment.
RESULTS: LINE-1 was hypermethylated in controls post- versus pre-deployment
(odds ratio [OR]: 1.33; 95% CI: 1.06-1.65) and hypomethylated in cases versus
controls postdeployment (OR: 0.82; 95% CI: 0.67-1.01). Alu was hypermethylated
for cases versus controls predeployment (OR: 1.46; 95% CI: 1.08-1.97).
CONCLUSION: Patterns of hypermethylation of LINE-1 in controls postdeployment
and of Alu in cases postdeployment are intriguing and may suggest resilience or
vulnerability factors. BACKGROUND: Epigenetic differences exist between trauma-exposed individuals with
and without post-traumatic stress disorder (PTSD). It is unclear whether these
epigenetic differences pre-exist, or arise following, trauma and PTSD onset.
METHOD: In pre- and post-trauma samples from a subset of Detroit Neighborhood
Health Study participants, DNA methylation (DNAm) was measured at DNA
methyltransferase 1 (DNMT1), DNMT3A, DNMT3B and DNMT3L. Pre-trauma DNAm
differences and changes in DNAm from pre- to post-trauma were assessed between
and within PTSD cases (n = 30) and age-, gender- and trauma exposure-matched
controls (n = 30). Pre-trauma DNAm was tested for association with post-trauma
symptom severity (PTSS) change. Potential functional consequences of DNAm
differences were explored via bioinformatic search for putative transcription
factor binding sites (TFBS).
RESULTS: DNMT1 DNAm increased following trauma in PTSD cases (p = 0.001), but
not controls (p = 0.067). DNMT3A and DNMT3B DNAm increased following trauma in
both cases (DNMT3A: p = 0.009; DNMT3B: p < 0.001) and controls (DNMT3A: p =
0.002; DNMT3B: p < 0.001). In cases only, pre-trauma DNAm was lower at a DNMT3B
CpG site that overlaps with a TFBS involved in epigenetic regulation (p =
0.001); lower pre-trauma DNMT3B DNAm at this site was predictive of worsening of
PTSS post-trauma (p = 0.034). Some effects were attenuated following correction
for multiple hypothesis testing.
CONCLUSIONS: DNAm among trauma-exposed individuals shows both longitudinal
changes and pre-existing epigenetic states that differentiate individuals who
are resilient versus susceptible to PTSD. These distinctive DNAm differences
within DNMT loci may contribute to genome-wide epigenetic profiles of PTSD. Traumatic stress results in hypothalamic pituitary adrenal (HPA) axis
abnormalities and an increased risk to both suicidal behaviors and
post-traumatic stress disorder (PTSD). Previous work out of our laboratory
identified SKA2 DNA methylation associations with suicidal behavior in the blood
and brain of multiple cohorts. Interaction of SKA2 with stress predicted
suicidal behavior with ~80% accuracy. SKA2 is hypothesized to reduce the ability
to suppress cortisol following stress, which is of potentially high relevance in
traumatized populations. Our objective was to investigate the interaction of
SKA2 and trauma exposure on HPA axis function, suicide attempt and PTSD. SKA2
DNA methylation at Illumina HM450 probe cg13989295 was assessed for association
with suicidal behavior and PTSD metrics in the context of Child Trauma
Questionnaire (CTQ) scores in 421 blood and 61 saliva samples from the Grady
Trauma Project (GTP) cohort. Dexamethasone suppression test (DST) data were
evaluated for a subset of 209 GTP subjects. SKA2 methylation interacted with CTQ
scores to predict lifetime suicide attempt in saliva and blood with areas under
the receiver operator characteristic curve (AUCs) of 0.76 and 0.73 (95%
confidence interval (CI): 0.6-0.92, P = 0.003, and CI: 0.65-0.78, P < 0.0001)
and to mediate the suppression of cortisol following DST (β = 0.5 ± 0.19, F =
1.51, degrees of freedom (df) = 12/167, P = 0.0096). Cumulatively, the data
suggest that epigenetic variation at SKA2 mediates vulnerability to suicidal
behaviors and PTSD through dysregulation of the HPA axis in response to stress. Genomic variation in the SKA2 gene has recently been identified as a promising
suicide biomarker. In light of its role in glucocorticoid receptor
transactivation, we investigated whether SKA2 DNA methylation influences
cortisol stress reactivity and is involved in the development of post-traumatic
stress disorder (PTSD). Increased SKA2 methylation was significantly associated
with lower cortisol stress reactivity in 85 healthy individuals exposed to the
Trier Social Stress Test (B=-173.40, t=-2.324, p-value=0.023). Next, we observed
that longitudinal decreases in SKA2 methylation after deployment were associated
with the emergence of post-deployment PTSD symptoms in a Dutch military cohort
(N=93; B=-0.054, t=-3.706, p-value=3.66 × 10(-4)). In contrast, exposure to
traumatic stress during deployment by itself resulted in longitudinal increases
in SKA2 methylation (B=0.037, t=4.173, p-value=6.98 × 10(-5)). Using
pre-deployment SKA2 methylation levels and childhood trauma exposure, we found
that the previously published suicide prediction rule significantly predicted
post-deployment PTSD symptoms (AUC=0.66, 95% CI: 0.53-0.79) with an optimal
sensitivity of 0.81 and specificity of 0.91. Permutation analysis using random
methylation loci supported these findings. Together, these data establish the
importance of SKA2 for cortisol stress responsivity and the development of PTSD
and provide further evidence that SKA2 is a promising biomarker for
stress-related disorders including PTSD. |
Is POLD3 essential for mouse development? | Yes. The Pold3 gene encodes a subunit of the Polδ DNA polymerase complex. Pold3 orthologs are not essential in Saccharomyces cerevisiae or chicken DT40 cells, but the Schizosaccharomyces pombe ortholog is essential. POLD3 also has a specialized role in the repair of broken replication forks, suggesting that POLD3 activity could be particularly relevant for cancer cells enduring high levels of DNA replication stress. In mouse, POLD3 is essential for development and is also required for viability in adult animals. | |
What is the mechanism of action of Romosozumab? | Romosozumab is humanized monoclonal antibody to sclerostin. It inhibits sclerostin, thereby increasing bone formation and decreasing bone resorption. This dual effect of romosozumab leads to rapid and substantial increases in areal bone mineral density as measured by dual-energy X-ray absorptiometry. It is developed for osteoporosis treatment. | Romosozumab (formerly AMG 785/CDP7851) is a monoclonal antibody that blocks
sclerostin from inhibiting osteoblast maturation and function. This
double-blind, placebo-controlled, randomized, ascending multiple-dose study
enrolled 32 postmenopausal women and 16 healthy men with low bone mass. Women
received six doses of 1 or 2 mg/kg once every 2 weeks (Q2W) or three doses of 2
or 3 mg/kg once every 4 weeks (Q4W) or placebo; and men received 1 mg/kg Q2W or
3 mg/kg Q4W or placebo. Mean serum romosozumab exposures increased approximately
dose-proportionally. Romosozumab increased serum type 1 aminoterminal propeptide
(PINP) by 66-147%, decreased serum C-telopeptide (sCTX) by 15-50%, and increased
lumbar spine bone mineral density by 4-7%. Two subjects developed neutralizing
antibodies without discernable effects on pharmacokinetics, pharmacodynamics, or
safety. Adverse event rates were balanced between groups without any significant
safety findings. These data support continued investigation of sclerostin
inhibition in disorders that could benefit from increased bone formation. BACKGROUND: Sclerostin is an osteocyte-derived inhibitor of osteoblast activity.
The monoclonal antibody romosozumab binds to sclerostin and increases bone
formation.
METHODS: In a phase 2, multicenter, international, randomized,
placebo-controlled, parallel-group, eight-group study, we evaluated the efficacy
and safety of romosozumab over a 12-month period in 419 postmenopausal women, 55
to 85 years of age, who had low bone mineral density (a T score of -2.0 or less
at the lumbar spine, total hip, or femoral neck and -3.5 or more at each of the
three sites). Participants were randomly assigned to receive subcutaneous
romosozumab monthly (at a dose of 70 mg, 140 mg, or 210 mg) or every 3 months
(140 mg or 210 mg), subcutaneous placebo, or an open-label active
comparator--oral alendronate (70 mg weekly) or subcutaneous teriparatide (20 μg
daily). The primary end point was the percentage change from baseline in bone
mineral density at the lumbar spine at 12 months. Secondary end points included
percentage changes in bone mineral density at other sites and in markers of bone
turnover.
RESULTS: All dose levels of romosozumab were associated with significant
increases in bone mineral density at the lumbar spine, including an increase of
11.3% with the 210-mg monthly dose, as compared with a decrease of 0.1% with
placebo and increases of 4.1% with alendronate and 7.1% with teriparatide.
Romosozumab was also associated with large increases in bone mineral density at
the total hip and femoral neck, as well as transitory increases in
bone-formation markers and sustained decreases in a bone-resorption marker.
Except for mild, generally nonrecurring injection-site reactions with
romosozumab, adverse events were similar among groups.
CONCLUSIONS: In postmenopausal women with low bone mass, romosozumab was
associated with increased bone mineral density and bone formation and with
decreased bone resorption. (Funded by Amgen and UCB Pharma; ClinicalTrials.gov
number, NCT00896532.). Osteolytic bone disease is the most common complication of multiple myeloma,
resulting in skeletal complications that cause significant morbidity and
mortality. Currently, bisphosphonates (BPs) are the mainstay for the treatment
of myeloma bone disease. Zoledronic acid which has been found to be superior to
clodronate, both in terms of reduction of skeletal-related events (SREs) and
survival, and pamidronate are used for the management of myeloma-related bone
disease. Patients with active disease (not in CR or VGPR) should receive BPs
(especially zoledronic acid) even after two years of administration.
Radiotherapy and surgical interventions can also be used for specific
conditions, such as pathological fractures, spinal cord compression or
uncontrolled pain. The better understanding of the biology of myeloma bone
disease has led to the production of several novel agents, such as denosumab
(targeting RANKL), sotatercept (activin-A antagonist) and romosozumab (targeting
sclerostin) that appear very promising and have entered to clinical development. INTRODUCTION: Disorders with inactivating mutations of the SOST gene result in
reduced or absent expression of sclerostin and are associated with high bone
mass. Sclerostin is an important regulator of bone formation due to its
inhibitory actions in the osteoanabolic Wnt signaling pathway. Advances in
understanding the mechanisms of action of this signaling molecule have led to
the development of a pharmacological inhibitor of sclerostin with potential
clinical applications as an osteoanabolic drug for the treatment of
osteoporosis.
AREAS COVERED: Romosozumab is the first humanized monoclonal sclerostin antibody
to be tested in clinical trials. Similar to preclinical animal studies with
sclerostin antibodies, initial clinical studies show that romosozumab increases
bone formation and bone mineral density.
EXPERT OPINION: Blocking sclerostin action with romosozumab is a promising new
therapeutic approach to osteoanabolic therapy of osteoporosis; efficacy and
safety data on large controlled studies are awaited. The Wnt pathway has an important role in bone formation. Inactivation of
sclerostin, an inhibitor of this pathway, has been associated with increased
bone mass both in animal experiments and in human clinical trials. Romosozumab
is a humanized monoclonal antibody targeting sclerostin. Preclinical studies
showed that this antibody primarily increases bone formation resulting in
increased bone mineral density. Initial studies carried out in humans are in
line with data obtained in animals. If these results are confirmed in larger
studies with fracture end-points, this monoclonal antibody with its anabolic
action, will become a key drug in the treatment of osteoporosis. Monoclonal antibodies to molecular targets important for bone formation and bone
resorption are being investigated for treatment of postmenopausal osteoporosis.
Postmenopausal osteoporosis is characterized by increased bone turnover, with
bone resorption typically exceeding bone formation. These pathophysiological
changes cause decreased bone mineral density and disruption of bone
microarchitecture which lead to low-trauma fractures. Sclerostin is a
glycoprotein inhibitor of osteoblast Wnt signaling produced by osteocytes that
has been recognized as a new target for therapeutic intervention in patients
with osteoporosis. Sclerostin was first recognized when disorders with
inactivating mutations of the sclerostin gene SOST were found to be associated
with high bone mass. These observations suggested that inhibitors of sclerostin
might be used to increase bone mineral density. Romosozumab (AMG 785) is the
first humanized anti-sclerostin monoclonal antibody that has been demonstrated
to increase bone formation. This investigational monoclonal antibody, and
blosozumab, another investigational anti-sclerostin antibody, have osteoanabolic
properties with the potential to improve clinical outcomes in patients with
osteoporosis. Similar to preclinical animal studies with sclerostin antibodies,
initial clinical studies have shown that romosozumab increases bone formation
and BMD. Further evaluation of the efficacy and safety of this agent in a large
phase III controlled study is awaited. Phase I clinical trial data have recently
been published with blosozumab. These novel interventions appear to be promising
agents for the treatment of osteoporosis. Odanacatib, a selective cathepsin K inhibitor, decreases bone resorption,
whereas osteoclast number increases and bone formation is maintained, perhaps
even increased on some cortical surfaces. In a phase 2 clinical trial,
post-menopausal women receiving odanacatib presented a sustained reduction of
bone resorption markers, whereas procollagen type 1 N-terminal propeptide
returned to normal. In turn areal bone mineral density increased continuously at
both spine and hip for up to 5 years. Blosozumab and romosozumab are sclerostin
neutralizing antibodies that exert potent anabolic effects on both trabecular
and cortical compartments. A phase 2 clinical trial has reported areal bone
mineral density gains at spine and hip that were greater with romosozumab
compared with placebo, but also with teriparatide. It also showed that
antagonizing sclerostin results in a transient stimulation of bone formation but
progressive inhibition of bone resorption. Other new medical entities that are
promising for the treatment of osteoporosis include abaloparatide, a parathyroid
hormone-related analogue with improved bone formation-resorption ratio. Romosozumab inhibits sclerostin, thereby increasing bone formation and
decreasing bone resorption. This dual effect of romosozumab leads to rapid and
substantial increases in areal bone mineral density (aBMD) as measured by
dual-energy X-ray absorptiometry (DXA). In a phase 1b, randomized, double-blind,
placebo-controlled study, romosozumab or placebo was administered to 32 women
and 16 men with low aBMD for 3 months, with a further 3-month follow-up: women
received six doses of 1 or 2mg/kg every 2 weeks (Q2W) or three doses of 2 or
3mg/kg every 4 weeks (Q4W); men received 1mg/kg Q2W or 3mg/kg Q4W. Quantitative
computed tomography (QCT) scans at lumbar (L1-2) vertebrae and high-resolution
QCT (HR-QCT) scans at thoracic vertebra (T12) were analyzed in a subset of
subjects at baseline, month 3, and month 6. The QCT subset included 24
romosozumab and 9 placebo subjects and the HR-QCT subset included 11 romosozumab
and 3 placebo subjects. The analyses pooled the romosozumab doses. Linear finite
element modeling of bone stiffness was performed. Compared with placebo, the
romosozumab group showed improvements at month 3 for trabecular BMD by QCT and
HR-QCT, HR-QCT trabecular bone volume fraction (BV/TV) and separation,
density-weighted cortical thickness, and QCT stiffness (all p<0.05). At month 6,
improvements from baseline were observed in QCT trabecular BMD and stiffness,
and in HR-QCT BMD, trabecular BV/TV and separation, density-weighted cortical
thickness, and stiffness in the romosozumab group (all p<0.05 compared with
placebo). The mean (SE) increase in HR-QCT stiffness with romosozumab from
baseline was 26.9% ± 6.8% and 35.0% ±6.8% at months 3 and 6, respectively;
subjects administered placebo had changes of -2.7% ± 13.4% and -6.4% ± 13.4%,
respectively. In conclusion, romosozumab administered for 3 months resulted in
rapid and large improvements in trabecular and cortical bone mass and structure
as well as whole bone stiffness, which continued 3 months after the last
romosozumab dose. Since the identification of osteoporosis as a major health issue in aging
populations and the subsequent development of the first treatment modalities for
its management, considerable progress has been made in our understanding of the
mechanisms controlling bone turnover and disease pathophysiology, thus enabling
the pinpointing of new targets for intervention. This progress, along with
advances in biotechnology, has rendered possible the development of ever more
sophisticated treatments employing novel mechanisms of action. Denosumab, a
monoclonal antibody against RANKL, approved for the treatment of postmenopausal
and male osteoporosis, significantly and continuously increases bone mineral
density (BMD) and maintains a low risk of vertebral, non-vertebral, and hip
fractures for up to 8 years. Currently available combinations of estrogens with
selective estrogen receptor modulators moderately increase BMD without causing
the extra-skeletal adverse effects of each compound alone. The cathepsin K
inhibitor odanacatib has recently been shown to decrease vertebral,
non-vertebral, and hip fracture rates and is nearing approval. Romosozumab, an
anti-sclerosin antibody, and abaloparatide, a PTH-related peptide analog, are at
present in advanced stages of clinical evaluation, so far demonstrating
efficaciousness together with a favorable safety profile. Several other agents
are currently in earlier clinical and preclinical phases of development,
including dickkopf-1 antagonists, activin A antagonists, β-arrestin analogs,
calcilytics, and Src tyrosine kinase inhibitors. Bone is constantly remodeled to maintain its volume, structural integrity and
strength Currently available bone anabolic agent is teriparatide. Teriparatide
increases bone mass and strength via both remodeling-dependent and -independent
mechanisms, although remodeling-dependent mechanism overweighs the other.
Canonical Wnt signal plays an important role in enhancing osteoblast
differentiation and bone formation, and its osteocyte-derived inhibitor,
sclerostin, regulates bone formation via the regulation of Wnt signaling.
Anti-sclerostin antibody stimulates Wnt signaling and enhances bone formation.
Phase II clinical trials with anti-sclerostin antibodies, romosozumab and
blosozumab, demonstrated a marked increase in bone mineral density after one
year of treatment. The new modality of anabolic agents via
remodeling-independent stimulation of bone formation may open up a new avenue
for the treatment of osteoporosis. For the prevention of fractures, antiresorptive drugs (bisphosphonates and
denosumab) that decrease high bone resorption and, secondarily, also bone
formation, are the mainstream of therapy. Osteoanabolic drugs, such as
teriparatide, increase bone formation more than bone resorption, and are used in
severe osteoporosis, including patients treated with antiresorptive drugs who
still lose bone and have recurrent fractures. New potential drugs for fracture
prevention that uncouple bone resorption from bone formation include odanacatib,
a specific inhibitor of cathepsin-K, the enzyme that degrades bone collagen type
I, that inhibits bone resorption and only temporarily bone formation, and
monoclonal antibodies against sclerostin (romosozumab, blosozumab), that
stimulate bone formation and decrease bone resorption. Several decades ago, a clinical condition that included severe bone overgrowth
was described in a few patients in South Africa. The autosomal-recessive disease
that later was named sclerosteosis was found to be caused by a mutation in the
SOTS gene causing a lack of the protein sclerostin. This protein is produced by
osteocytes and exerts its effect as an inhibitor of bone formation by blocking
the Wnt signaling pathway. By the use of a monoclonal antibody that can block
sclerostin a novel therapeutic pathway for rebuilding bone has been described.
Preclinical studies have shown increased bone mass following subcutaneously
administered anti-sclerostin antibody in animals with induced postmenopausal
osteoporosis as well as in intact male rats and non-human primates. In a phase
II study the efficacy and safety of an anti-sclerostin antibody, romosozumab,
has been evaluated in 419 postmenopausal women for 12 months. 70, 140 or 210 mg
was given subcutaneously monthly or every three months and compared to 70 mg of
oral alendronate given once a week or 20 μg of teriparatide subcutaneously once
daily. All dose levels of romosozumab were associated with significant increase
in BMD with the most pronounced gain in the group receiving 210 mg where lumbar
spine BMD increased with 11.3% from baseline. The BMD for the placebo group
decreased by 0.1% while the alendronate group increased 4.1% and the
teriparatide increased 7.1%. Biochemical markers revealed a transitory increase
in the bone formation marker P1NP while no change in the bone resorption marker
β-CTX. In comparison, teriparatide resulted in an increase for both P1NP and
β-CTX for the complete study period. Even though the rapid gain in BMD is
promising when considering a treatment option for osteoporosis and other
conditions with bone loss, there are so far no published studies on whether
anti-sclerostin can reduce the number of fractures. Wnt signaling might also
play an important role in fracture healing with substances that causes an
upregulation of the Wnt pathway producing enhancement of the fracture healing
process. Healing of experimental fractures in various animal models have shown
improvement following subcutaneously administered anti-sclerostin antibody.
While there are no published reports on the potential effect of systemically
administered anti-sclerostin antibodies on fracture healing in humans. Romosozumab is a humanized immunoglobulin G2 monoclonal antibody that binds and
blocks the action of sclerostin, a protein secreted by the osteocyte and an
extracellular inhibitor of canonical Wnt signaling. Blockade of sclerostin
binding to low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and
LRP6) allows Wnt ligands to activate canonical Wnt signaling in bone, increasing
bone formation and decreasing bone resorption, making sclerostin an attractive
target for osteoporosis therapy. Because romosozumab is a bone-forming agent and
an activator of canonical Wnt signaling, questions have arisen regarding a
potential carcinogenic risk. Weight-of-evidence factors used in the assessment
of human carcinogenic risk of romosozumab included features of canonical Wnt
signaling, expression pattern of sclerostin, phenotype of loss-of-function
mutations in humans and mice, mode and mechanism of action of romosozumab, and
findings from romosozumab chronic toxicity studies in rats and monkeys. Although
the weight-of-evidence factors supported that romosozumab would pose a low
carcinogenic risk to humans, the carcinogenic potential of romosozumab was
assessed in a rat lifetime study. There were no romosozumab-related effects on
tumor incidence in rats. The findings of the lifetime study and the
weight-of-evidence factors collectively indicate that romosozumab administration
would not pose a carcinogenic risk to humans. |
Symptoms of which disorder are evaluated with the Davidson Trauma Scale? | Davidson Trauma Scale is used for evaluation of post-traumatic stress disorder. | BACKGROUND: In post-traumatic stress disorder (PTSD) there is a need for
self-rating scales that are sensitive to treatment effects and have been tested
in a broad range of trauma survivors. Separate measures of frequency and
severity may also provide an advantage.
METHODS: Three hundred and fifty-three men and women completed the Davidson
Trauma Scale (DTS), a 17-item scale measuring each DSM-IV symptom of PTSD on
5-point frequency and severity scales. These subjects comprised war veterans,
survivors of rape or hurricane and a mixed trauma group participating in a
clinical trial. Other scales were included as validity checks as follows: Global
ratings, SCL-90-R, Eysenck Scale, Impact of Event Scale and Structured Clinical
Interview for DSM-III-R.
RESULTS: The scale demonstrated good test-retest reliability (r = 0.86),
internal consistency (r = 0.99). One main factor emerged for severity and a
smaller one for intrusion. In PTSD diagnosed subjects, and the factor structure
more closely resembled the traditional grouping of symptoms. Concurrent validity
was obtained against the SCID, with a diagnostic accuracy of 83% at a DTS score
of 40. Good convergent and divergent validity was obtained. The DTS showed
predictive validity against response to treatment, as well as being sensitive to
treatment effects.
CONCLUSIONS: The DTS showed good reliability and validity, and offers promised
as a scale which is particularly suited to assessing symptom severity, treatment
outcome and in screening for the likely diagnosis of PTSD. The selective serotonin reuptake inhibitors have become a first line treatment
for post-traumatic stress disorder (PTSD). In a recent double-blind study in
civilians, fluoxetine produced clinically and statistically significant effects
on all general measures of PTSD. We examined the specific effects of fluoxetine
versus placebo in the above mentioned study of PTSD clusters and individual
symptoms. Individuals were included if they met criteria for PTSD according to
the Structured Clinical Interview for DSM-III-R (SCID). Symptoms were assessed
at sequential time points by the Structured Interview for PTSD (SIP), a
clinician interview based assessment, and a self-report scale, the Davidson
Trauma Scale (DTS). A total of 53 patients were included in the analysis. On the
SIP and DTS, fluoxetine was found to produce statistically significant changes
on all clusters. Significant effects for fluoxetine were noted on 10 items of
the DTS, and 8 items of the SIP. The SIP and DTS had 6 items in common that were
significant. Fluoxetine exerts a broad spectrum effect in reducing all the
symptom clusters of PTSD in this sample. The symptoms of being physically upset
at reminders of the trauma, avoiding thoughts of the trauma, having difficulty
enjoying things, feeling distant/estranged, having a sense of foreshortened
future, and impaired concentration, were the symptoms most responsive to the
effects of treatment with fluoxetine on both scales. This report describes the reliability, validity, treatment sensitivity,
diagnostic performance and normative values for the Short Post-Traumatic Stress
Disorder (PTSD) Rating Interview (SPRINT), a brief, global assessment for PTSD.
The SPRINT was administered to subjects participating in a clinical trial of
PTSD and in a population survey assessing PTSD prevalence. The 8-item SPRINT
includes questions assessing the core symptoms of PTSD, as well as related
aspects of somatic malaise, stress vulnerability and functional impairment.
Validity was assessed against the MINI structured interview, the Davidson Trauma
Scale, Treatment Outcome for PTSD Scale, Connor-Davidson Resilience Scale,
Sheehan Stress Vulnerability Scale, Sheehan Disability Scale and Clinical Global
Impressions of Severity and Improvement Scales. Good test-retest reliability,
internal consistency, convergent and divergent validity were obtained. The
SPRINT was responsive to symptom change over time and correlated with comparable
PTSD symptom measures. In victims of trauma, a score of 14-17 was associated
with 96% diagnostic accuracy, whereas in those with PTSD, highest efficiency
corresponded to a range of 11-13. The SPRINT demonstrates solid psychometric
properties and can serve as a reliable, valid and homogeneous measure of PTSD
illness severity and of global improvement. The Chinese version of the Davidson Trauma Scale (DTS-C) was developed to
respond to the need of Chinese-speaking individuals. The DTS is a validated
self-rating scale used in the diagnosis of posttraumatic stress disorder (PTSD).
The DTS-C is translated from DTS through a two-stage translation. Subjects were
drawn from a sample of 210 survivors of the 21 September 1999, Chi-Chi
Earthquake. The scale showed good internal consistency (Cronbach's alpha = 0.97)
and test-retest reliability (r = 0.88). Concurrent validity was obtained against
the clinical diagnostic interview, with a diagnostic accuracy of 0.85 at DTS-C
score of 44. It showed that the sensitivity was 0.9, specificity 0.81, positive
likelihood ratio 4.74, and negative likelihood ratio 0.12. The recommended
stratum-specific likelihood ratios were 0.10 (95% CI: 0.05-0.20) for the score
range 0-39, 4 (2.22-7.23) for the score range of 40-59, and 6.14 (3.42-11.02)
for the scores above 60. In PTSD diagnosed subjects, the factor structures
closely resembled the DSM-IV grouping of PTSD symptoms. The psychometric
strength of DTS-C is reliable for its future use, particularly for screening for
subjects with possible diagnosis of PTSD. BACKGROUND: The serotonergic system is implicated in the pathophysiology of
posttraumatic stress disorder (PTSD) and depression. The present study focused
on platelet serotonin (5-HT) concentration and symptoms of comorbid depression
in war veterans with or without PTSD.
METHODS: PTSD and depression were evaluated using Clinician Administered PTSD
Scale, Davidson Trauma Scale, Montgomery-Asberg Depression Rating Scale and
Hamilton Anxiety Scale. Sixty-five male drug-free war veterans (48 with PTSD and
17 without PTSD) and 65 age- and sex-matched healthy controls were studied.
RESULTS: Comorbid depression occurred in 54 and 31% of war veterans with PTSD
and without PTSD, respectively. Platelet 5-HT concentration was similar in the
groups of depressed and nondepressed war veterans with or without PTSD and
healthy controls. Platelet 5-HT concentration was found to differ between war
veterans with various degrees of appetite loss. A positive correlation was
observed between platelet 5-HT concentration and severity of appetite loss in
veterans with PTSD. There was no relationship between platelet 5-HT
concentration and severity of other symptoms of PTSD or depression.
LIMITATIONS: War veterans included in the study were outpatients.
CONCLUSIONS: War veterans with PTSD had a high incidence of comorbid depression,
that was not related to platelet 5-HT concentration. The marked relationship
between platelet 5-HT concentration and severity of appetite loss, suggested
that 5-HT system is involved in the regulation of appetite, at least in
depressed war veterans with PTSD. Rates of remission were examined in two controlled 12-week studies of sertraline
and placebo for post-traumatic stress disorder (PTSD). The performance of three
scales was evaluated: the self-rated Davidson Trauma Scale (DTS), and two
interviewer scales: the Clinician Administered PTSD Scale (CAPS) and Clinical
Global Impressions (CGI). Sertraline proved significantly superior to placebo
with respect to remission on all three ratings. Rates of remission were very
similar for all scales, ranging from 23.1-26.3% for sertraline and 13.9-14.9%
for placebo. Traditional thresholds for the CAPS and DTS were tested relative to
the CGI and to each other. The CAPS and DTS thresholds of < 20 and < 18 were
found to be valid. Interest in the psychiatric consequences of trauma and the subsequent surgical
intervention has been increasing steadily; therefore, the authors assessed the
prevalence of acute symptoms of stress in patients who experienced a
craniomaxillofacial injury. Fifty patients between the ages of 18 and 65 years
were evaluated and assigned a score using the Injury Severity Scale (ISS).
Within 48 hours of surgery (T0) and at 3 months after surgery (T1), the authors
administered the Davidson Trauma Scale (DTS) to assess post-traumatic symptoms,
Spielberger's State-Trait Anxiety Inventory (STAI) to assess symptoms of
anxiety, and Zung's Self-rating Depression Scale (SDS) to assess depressive
symptoms. Of the subjects, 44% (22 patients at T0) had acute symptoms of stress,
and 26% (13 patients at T1) had post-traumatic stress symptoms. The statistical
association between demographic variables was significant only for gender,
especially for women. There was a significant correlation between the
psychopathologic variables and trauma-specific symptoms at both T0 and T1; the
same was true for the ISS at T0. Eight of the 13 patients with positive DTS
results at 3 months had aesthetic and functional sequelae that might have served
as reminders of the traumatic event. It is not only necessary to restitutio ad
integrum the anatomy and function, but also to provide psychiatric support for
patients experiencing psychiatric symptoms caused by traumatic events. This study evaluated the effectiveness of quetiapine for subjects with
post-traumatic stress disorder (PTSD) who were already on a stable dose of a
selective serotonin reuptake inhibitor (SSRI) but had significant PTSD symptoms.
Fifteen subjects were enrolled in an 8-week open-label trial for PTSD in which
quetiapine was added to an SSRI. Subjects were on a stable dose of the SSRI for
at least 6 weeks before study entry and had a Clincian-Administered PTSD Scale
(CAPS) score of greater than or equal to 50 at study baseline. The mean age of
subjects was 49 years (eight men and seven women). The average duration of PTSD
was 29 years, one-third of subjects had combat-related PTSD, and two-thirds had
noncombat PTSD. The mean dose prescribed in the study was 216 mg per day. The
initial median CAPS score was 80, indicating severe PTSD. The addition of a
modest dose of quetiapine provided significant relief from PTSD symptoms with a
42% overall improvement in PTSD symptoms based on the CAPS and significant
improvement along each dimension of symptoms: re-experiencing (Z=-3.24,
P=0.0012), hyperarousal (Z=-3.30, P=0.001) and avoidance (Z=-2.13, P=0.03).
Subjects rated themselves as 45% improved on average on the Davidson Trauma
Scale and reported a 44% decrease in their level of disability and impairment as
reflected by the Sheehan Disability Scale. Subjects with PTSD who had
significant PTSD symptoms when on an SSRI benefited from the addition of
quetiapine. Patients improved significantly on all three clusters of PTSD
symptoms: re-experiencing, hyperarousal and avoidance. The Web site for the Anxiety Disorders Association of America (ADAA) receives
more than 5 million visits per month and thus represents a unique medium for the
study of anxiety disorders. ADAA Web site users from October 2002 to January
2003 were invited to complete a survey oriented toward trauma history and
psychiatric sequelae. A diagnostic approximation of posttraumatic stress
disorder (PTSD) was based on responses to the Trauma Questionnaire, the Davidson
Trauma Scale, and questions about impairment. The Connor-Davidson Resilience
Scale was also used. Variables were tested for their association with PTSD.
Among 1558 participants, 87% had a history of trauma, and 38% had current PTSD.
The population was comprised predomitly of white middle-class women, half of
whom were married. More than 90% were first-time users of the site. Factors
associated with PTSD included death of, or harm to, a loved one; personal
history of incest, rape, or physical abuse; lower age; lower income;
unemployment; missed work; increased medical care; dissatisfaction with
psychotropic medication; depressive symptoms; and lower resilience. In this
selective convenience sample, there were high rates of traumatization and PTSD.
The demographics of this group are similar to those seen in previously studied
populations that had contacted the ADAA. Furthermore, the factors associated
with PTSD were like those in many community surveys. The ADAA Web site has the
opportunity to benefit large numbers of highly distressed individuals. PURPOSE: To determine the change in prevalence of posttraumatic stress disorder
(PTSD) symptoms in victims of the March 11 attacks and their relatives, 1 and 6
months after the attacks.
SUBJECTS AND METHODS: Evaluation of PTSD symptoms using the Davidson Trauma
Scale (DTS) and General Health Questionnaire (GHQ) in a sample of 56 patients
admitted to an emergency room of a general hospital, and assessment of PTSD
symptoms in relatives of the patients.
RESULTS: At Month 1, 41.1% of patients (31.3% of males and 54.2% of females)
presented with PTSD. At Month 6, this figure was 40.9% (30.4% of males and 52.4%
of females). There was a significant improvement in perception of health among
females between Month 1 and Month 6. Relatives presented similar DTS scores at
baseline and at 6 months.
DISCUSSION: We verified that rates of PTSD did not vary substantively between
the two evaluations. PTSD symptoms positively correlated with psychological
health involvement. This correlation points out that both PTSD symptoms and
subjective general health involvement are part of the psychological response to
trauma.
CONCLUSION: The prevalence of PTSD symptoms was high and remained stable between
Month 1 and Month 6, while subjective perception of health improved
significantly. The aim of this study was to evaluate the efficacy and tolerability of tiagabine
in adult patients with post-traumatic stress disorder (PTSD). This 12-week,
multicenter, double-blind study randomized patients to receive either tiagabine
or placebo. Tiagabine (administered in divided doses) was initiated at 4 mg/d (2
mg BID) and individually titrated of up to 4 mg/d weekly to a maximum dose of 16
mg/d. Assessments included the Clinician-Administered PTSD Scale, Clinical
Global Impressions of Change, Treatment Outcome PTSD Scale, Davidson Trauma
Scale, Connor-Davidson Resilience Scale, Sheehan Disability Scale, Massachusetts
General Hospital Sexual Functioning Questionnaire, and Montgomery-Asberg
Depression Rating Scale. A total of 232 patients (tiagabine, n = 116; placebo, n
= 116) were randomized. There were no significant differences in change from
baseline in the Clinician-Administered PTSD Scale total score at final visit for
tiagabine compared with placebo (P = 0.85). Similarly, no significant
differences were observed with tiagabine on the other efficacy outcome measures
(described above) compared with placebo. Tiagabine was generally well tolerated
and not associated with weight gain, changes in sexual function, or worsening of
depressive symptoms. Tiagabine was not significantly different from placebo in
the treatment of symptoms of PTSD. Additional studies are needed to assess the
role of drugs that target the gamma-aminobutyric acid system in the treatment of
PTSD. The Davidson Trauma Scale (DTS) is a validated, 17-item, brief global assessment
scale for posttraumatic stress disorder (PTSD). The purposes of this study were
to develop a Korean version of the DTS (DTS-K) while maintaining its basic
structure and to evaluate its reliability and validity for the Korean
population. Participants of this study included 93 patients with PTSD (PTSD
group), 73 patients with nonpsychotic mood or other anxiety disorders
(psychiatric control group), and 88 healthy controls (normal control group).
Subjects completed psychometric assessments, including the DTS-K and the Korean
version of the Clinician-Administered PTSD Scale and the State Trait Anxiety
Inventory. The DTS-K showed good internal consistency (Cronbach alpha = .97) and
test-retest reliability (r = .93). The DTS-K showed a significantly positive
correlation with Clinician-Administered PTSD Scale (r = .94). The highest
diagnostic efficiency of DTS-K was at a total score of 47, with sensitivity and
specificity of 0.87 and 0.84, respectively. Our findings suggest that the DTS-K
is composed of good psychometric properties and is a valid and reliable tool for
assessing the frequency and severity of PTSD symptoms regardless of ethnicity. In this study psychometric properties of seven self-report measures of
posttraumatic stress disorder (PTSD) were compared. The seven scales evaluated
were the Davidson Trauma Scale (DTS), the PTSD Checklist (PCL), the
Posttraumatic Stress Diagnostic Scale (PDS), the Civilian Mississippi Scale
(CMS), the Impact of Event Scale-Revised (IES-R), the Penn Inventory for
Posttraumatic Stress Disorder (Penn), and the PK scale of the MMPI-2 (PK).
Participants were 239 (79 male and 160 female) trauma-exposed undergraduates.
All seven measures exhibited good test-retest reliability and internal
consistency. The PDS, PCL and DTS demonstrated the best convergent validity; the
IES-R, PDS, and PCL demonstrated the best discrimit validity; and the PDS,
PCL, and IES-R demonstrated the best diagnostic utility. Overall, results most
strongly support the use of the PDS and the PCL for the assessment of PTSD in
this population. BACKGROUND: This study examined the accuracy of the 17-item Dutch version of the
Davidson Trauma Scale (DTS) and the four-item SPAN (Startle, Physiological
Arousal, Anger and Numbness) to detect survivors at risk for posttraumatic
stress disorder (PTSD) within the first 2 weeks after the trauma.
METHODS: 203 civilian survivors of recent trauma with relatively mild symptoms
completed the DTS a mean of 8.7 days after experiencing trauma. SPAN scores were
computed from the DTS. At a mean of 64.6 days posttrauma, 160 respondents were
assessed for diagnosis of PTSD with the Structured Interview for PTSD.
RESULTS: Receiver operating characteristic curves showed that the DTS showed
good overall screening accuracy (84%). At a cut-off value of 64, the DTS
demonstrated a sensitivity of 0.86, a specificity of 0.70, a positive predictive
value (PPV) of 0.12, and a negative predictive value (NPV) of 0.98. Overall
accuracy of the SPAN was good (89%). At a cut-off of 10 the SPAN showed a
sensitivity of 0.86, a specificity of 0.86, a PPV of 0.22, and a NPV of 0.98.
The low PPVs were possibly due to the low of prevalence of PTSD in our sample
(4.4%).
CONCLUSIONS: This study shows that both the DTS and the SPAN are comparably
accurate in screening early trauma survivors at risk for developing PTSD. The
very brief four-item SPAN may be preferred over the longer 17-item DTS
especially in settings in which time and resources are limited. Future studies
should aim to cross-validate these results in random samples. BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) are first-line
treatments for posttraumatic stress disorder (PTSD). Serotonergic (5HT)
attenuation of stress sensitivity is postulated from SSRIs' effects in other
anxiety disorders, and we studied this in PTSD.
METHODS: Ten patients with PTSD fully recovered on SSRIs (Clinical Global
Impression Scale-I 1 and 2) were enrolled in the study. Patients were tested on
two occasions 1 week apart; in each session, they received a drink containing
large neutral amino acids (LNAAs) either with (sham tryptophan depletion [STD],
control) or without (acute tryptophan depletion [ATD]) tryptophan. At 5.5 hours
after the drink, subjects were exposed to a trauma-related exposure challenge.
Self-reports of PTSD (visual analogue scales [VAS] and the Davidson Trauma Scale
[DTS]), anxiety (Spielberger State Inventory [STAI] Form Y-1), and mood (Profile
of Mood States [POMS]) were obtained. Heart rate (HR), systolic (SBP) and
diastolic (DBP) blood pressure were also measured.
RESULTS: The trauma-related exposure challenge induced anxiety on both days,
with more marked responses on the ATD day according to VAS, DTS, POMS, and DBP
(p < .05). A trend of significance (.1 > p > .05) was observed for STAI Form
Y-1, HR, and SBP.
CONCLUSIONS: These data demonstrate that ATD accentuates responses to
trauma-related stimuli in SSRI-recovered PTSD. They also suggest that
SSRI-induced increases in serotonin function restrain PTSD symptoms, especially
under provocation, supporting a role for serotonin in mediating stress
resilience. Empirical data have challenged chronic posttraumatic stress disorder (PTSD)
consisting of three dimensions. In the present study we aimed to determine the
factor structure of acute posttraumatic symptoms in two recently traumatized
samples. In sample 1, 203 civilian trauma survivors were administered the
Davidson Trauma Scale (DTS) approximately 1 week posttrauma. In sample 2, 182
civilian treatment seeking trauma survivors completed the DTS at an average of
41.4 days posttrauma. Our confirmatory factor analyses indicated that a 4-factor
intercorrelated model provided the best representation of the data in both
samples. The four factors are best described as reexperiencing, active
avoidance, dysphoria, and hyperarousal. For acute posttraumatic symptoms, the
empirical data suggest to split the avoidance cluster into 'Active avoidance'
and 'Dysphoria'-confirming findings in studies on chronic PTSD. In future
revisions of the DSM, the diagnostic criteria for PTSD may need to be adapted to
fit the research findings. OBJECTIVE: Previous studies have suggested a link between heart rate (HR)
following trauma and the development of posttraumatic stress disorder (PTSD).
This study expands on previous work by evaluating HR in burn patients followed
longitudinally for symptoms of acute stress disorder (ASD) and PTSD.
METHOD: Data were collected from consecutive patients admitted to the Johns
Hopkins Burn Center, Baltimore, Maryland, between 1997 and 2002. Patients
completed the Stanford Acute Stress Reaction Questionnaire (n = 157) to assess
symptoms of ASD. The Davidson Trauma Scale was completed at 1 (n = 145), 6 (n =
106), 12 (n = 94), and 24 (n = 66) months postdischarge to assess symptoms of
PTSD. Heart rate in the ambulance, emergency room, and burn unit were obtained
by retrospective medical chart review.
RESULTS: Pearson correlations revealed a significant relationship between HR in
the ambulance (r = 0.32, P = .016) and burn unit (r = 0.30, P = .001) and ASD
scores at baseline. Heart rate in the ambulance was related to PTSD avoidance
cluster scores at 1, 6, 12, and 24 months. In women, HR in the ambulance was
correlated with PTSD scores at 6 (r = 0.65, P = .005) and 12 (r = 0.78, P =
.005) months. When covariates (gender, β-blockers, Brief Symptom Inventory
Global Severity Index score) were included in multivariate linear regression
analyses, ambulance HR was associated with ASD and PTSD scores at baseline and 1
month, and the interaction of ambulance HR and gender was associated with PTSD
scores at 6 and 12 months. Multivariate logistic regression results were similar
at baseline and 12 months, which included an HR association yet no interaction
at 6 months and a marginal interaction at 1 month.
CONCLUSIONS: While peritraumatic HR is most robustly associated with PTSD
symptom severity, HR on admission to burn unit also predicts the development of
ASD. Gender and avoidance symptoms appear particularly salient in this
relationship, and these factors may aid in the identification of subgroups for
which HR serves as a biomarker for PTSD. Future work may identify endophenotypic
measures of increased risk for PTSD, targeting subgroups for early intervention. INTRODUCTION: Pakistan's 2005 earthquake claimed almost 87,000 lives and
displaced millions. The present study sought to assess PTSD prevalence among
earthquake survivors, to evaluate its determits, and to identify protective
factors that suggest future interventions in the aftermath of disasters.
METHODS: In a cross-sectional survey, three districts were selected based on
their proximity to the epicenter and the presence, accessibility, and security
of refugees, 300 earthquake survivors were enrolled.
RESULTS: Analysis revealed that after 30months, PTSD prevalence was high. Being
female, older, unmarried, head of the family, and currently unemployed and
having low income and living in temporary housing confer higher risks of PTSD.
Having a high social capital and religious inclination seem to have protective,
buffer effect and increase resilience against PTSD.
CONCLUSION: This is the first post-quake study in Pakistan that has utilized,
adapted and validated Davidson Trauma Scale in the local context. Results imply
the significance of continued psychological support, of drawing on resilience
factors in PTSD management. Implications and directions for future research are
discussed. Emerging data suggest that second-generation antipsychotics such as aripiprazole
may be effective in the treatment of post-traumatic stress disorder (PTSD).
However, few clinical trials have used aripiprazole in PTSD, and data are
limited on its use in Veterans with PTSD. The objective of this pilot trial was
to investigate the safety and efficacy of aripiprazole in Veterans with PTSD.
Ten individuals (five men and five women) meeting the Diagnostic and statistical
manual of mental disorders, 4th ed., PTSD criteria participated in this 12-week,
open-label, flexibly dosed monotherapy trial. The dose range of aripiprazole was
5-30 mg/day, titrated to tolerability and clinical response. The primary outcome
measure was the Clinician-Administered PTSD Scale. Additional outcomes included
the Short PTSD Rating Interview, the Treatment Outcome PTSD Scale (Top-8), the
Davidson Trauma Scale, the Positive and Negative Syndrome Scale, the Beck
Depression Inventory-Fast Screen, and Clinical Global Impressions-Improvement.
Eight participants completed the study, and aripiprazole was generally well
tolerated and associated with a significant improvement in PTSD symptoms, as
measured by the Clinician-Administered PTSD Scale (primary outcome measure) and
by the Short PTSD Rating Interview, the Treatment Outcome PTSD Scale, and the
Davidson Trauma Scale. An improvement was also observed on all three Positive
and Negative Syndrome Scale subscales and the Beck Depression Inventory-Fast
Screen, and the average Clinical Global Impressions-Improvement ratings
indicated that patients were 'much improved'. These promising initial results
merit further investigation in a larger, randomized-controlled trial. BACKGROUND: We evaluated the role that selected variants in serotonin
transporter (5-HTT), dopamine receptor 2 (DRD2) and brain-derived neurotrophic
factor (BDNF) genes play in PTSD symptom severity in an at-risk population. We
also investigated the interaction between the genetic variants to determine
whether these variables and the interactions between the variables influenced
the severity of PTSD symptoms.
METHODS: PTSD symptoms were quantitatively assessed using the Davidson Trauma
Scale (DTS) in 150 participants from an at-risk South African population. All
participants were genotyped for the 5-HTTLPR, DRD2 Taq1A and BDNF Val66Met
polymorphisms. Gene-gene interactions were investigated using various linear
models. All analyses were adjusted for age, gender, major depressive disorder
diagnosis, level of resilience, level of social support and alcohol dependence.
RESULTS: A significant interaction effect between DRD2 Taq1A and BDNF Val66Met
variants on DTS score was observed. On the background of the BDNF Val66Val
genotype, DTS score increased significantly with the addition of a DRD2 Taq1A A1
allele. However, on the BDNF Met66 allele background, the addition of an A1
allele was found to reduce total DTS score.
CONCLUSIONS: This study provides preliminary evidence for an epistatic
interaction between BDNF Val66Met and DRD2 Taq1A polymorphisms on the severity
of PTSD symptoms, where both too little and too much dopamine can result in
increased PTSD symptom severity. OBJECTIVE: This study aimed to explore retrospective childhood ADHD
symptomatology, psychiatric comorbidity, rates of substance-use disorders (SUD),
as well as their association with high-risk health behaviors in prison and
adverse health outcomes.
METHOD: A randomly selected representative sample of inmates in the Puerto Rico
correctional system (N = 1,179) was assessed with the Spanish-language Wender
Utah Rating Scale (WURS); the Composite International Diagnostic Interview
(CIDI) modules for lifetime/current major depression disorder (MDD), generalized
anxiety disorder (GAD), and SUD; the Davidson Trauma Scale (DTS; posttraumatic
stress disorder [PTSD]); and self-reports of in-site high-risk behaviors.
RESULTS: Wald χ(2) tests revealed significant associations of ADHD with MDD and
PTSD, as well as increased risk for overdosing and intravenous drug use in
prison. A logistic regression model adjusted for mood and anxiety comorbidity
predicted lifetime SUD diagnosis (odds ratio = 2.38; 95% confidence interval =
[1.15, 4.94]).
CONCLUSION: Our results provide further evidence on the association of drug
dependence and ADHD symptoms, and their overrepresentation among prison inmates. OBJECTIVE: Symptoms of posttraumatic stress disorder are a well-recognized
phenomenon in mothers of preterm infants, with implications for maternal health
and infant outcomes. This randomized controlled trial evaluated 6-month outcomes
from a skills-based intervention developed to reduce symptoms of posttraumatic
stress disorder, anxiety, and depression.
METHODS: One hundred five mothers of preterm infants were randomly assigned to
(1) a 6- or 9-session intervention based on principles of trauma-focused
cognitive behavior therapy with infant redefinition or (2) a 1-session active
comparison intervention based on education about the NICU and parenting of the
premature infant. Outcome measures included the Davidson Trauma Scale, the Beck
Depression Inventory II, and the Beck Anxiety Inventory. Participants were
assessed at baseline, 4 to 5 weeks after birth, and 6 months after the birth of
the infant.
RESULTS: At the 6-month assessment, the differences between the intervention and
comparison condition were all significant and sizable and became more pronounced
when compared with the 4- to 5-week outcomes: Davidson Trauma Scale (Cohen's d =
-0.74, P < .001), Beck Anxiety Inventory (Cohen's d = -0.627, P = .001), Beck
Depression Inventory II (Cohen's d = -0.638, P = .002). However, there were no
differences in the effect sizes between the 6- and 9-session interventions.
CONCLUSIONS: A brief 6-session intervention based on principles of
trauma-focused cognitive behavior therapy was effective at reducing symptoms of
trauma, anxiety, and depression in mothers of preterm infants. Mothers showed
increased benefits at the 6-month follow-up, suggesting that they continue to
make use of techniques acquired during the intervention phase. BACKGROUND: The apolipoprotein E (APOE) ε4 allele has been implicated in a range
of neuropsychiatric conditions. The present research examined if the ε4 allele
of the APOE gene moderated the effect of combat exposure on posttraumatic stress
disorder (PTSD) among Iraq/Afghanistan-era veterans.
METHOD: Participants included 765 non-Hispanic White (NHW) and 859 non-Hispanic
Black (NHB) Iraq/Afghanistan-era veterans. A structured interview established
psychiatric diagnoses. Combat exposure and PTSD symptom severity were assessed
via self-report.
RESULTS: The most common lifetime diagnoses were depression (39.2%), PTSD
(38.4%), and alcohol dependence (24.38%). After correcting for multiple
comparisons, no significant effects were observed on any of the outcomes among
the NHW sample; however, within the NHB sample, significant gene × environment
(G × E) interactions were observed for lifetime PTSD (P = .0029) and PTSD
symptom severity (P = .0009). In each case, the APOE ε4 allele had no effect on
the outcomes when combat exposure was low; however, when combat exposure was
high, an additive effect was observed such that ε4 homozygotes exposed to high
levels of combat reported the highest rates of PTSD (92%) and the worst symptom
severity scores on the Davidson Trauma Scale (M = 79.5).
CONCLUSIONS: Although preliminary, these findings suggest that the APOE ε4
allele, in conjunction with exposure to high levels of combat exposure, may
increase veterans' risk for developing PTSD. PURPOSE: The purpose of this paper is to assess the reliability and validity of
the Spanish version of the Davidson trauma scale (DTS-S) and to determine the
prevalence and correlates of post-traumatic stress disorder (PTSD) symptoms in a
non-clinical random sample of prison inmates.
DESIGN/METHODOLOGY/APPROACH: Probabilistic samples of 1,179 inmates from 26
penal institutions in Puerto Rico were selected using a multistage sampling
design. Population estimates and correlations were obtained for PTSD,
generalized anxiety and depression. The reliability, factor structure, and
convergent validity of the DTS-S were assessed. Cross-validation was employed to
confirm the results of the factor analyses.
FINDINGS: Using the cut-offs adopted by the scale's author, 136 (13.4 percent)
of the inmates are likely to have current PTSD and 117 (11.6 percent) reach the
cut-off for sub-threshold PTSD. Confirmatory factor analysis generated two
factors explaining 53 percent of the variance. High reliabilities were obtained
for the total scale (α=0.95) and for the frequency and severity scales (α=0.90
and 0.91). Significantly higher DTS-S scores were found for females (t=2.26,
p<0.025), for inmates diagnosed with depression or anxiety (t=2.02, p<0.05), and
those reporting suicide attempts (t=4.47, p<0.0001).
ORIGINALITY/VALUE: Findings support that the DTS-S is a reliable and valid
measure to assess PTSD symptoms in Latino inmate populations and to identify
individuals at risk for the disorder that require confirmatory diagnosis and
clinical interventions. Resilience is defined as the ability to recover from stress. However, all
resilience measures with exception of the Brief Resilience Scale (BRS) assess
resources that make resilience possible instead of recovery. The purpose of this
study was to translate the BRS to Spanish and to analyze the reliability and
validity of its scores. The psychometric properties of its scores were examined
in a heterogeneous sample of 620 Spanish adults. Confirmatory factor analyses
were carried out to study its scores' evidence of structural validity. Besides,
to study its scores' evidence of convergent, discrimit, and predictive
validity in relation to other resilience questionnaires (Connor Davidson
Resilience Scale 10-item version, Situated Subjective Resilience Questionnaire
for Adults and Resiliency Questionnaire for Adults) and to variables such as
emotions (Modified Differential Emotions Scale), coping (Person-situation Coping
Questionnaire for Adults), anxiety and depression (Hospital Anxiety and
Depression Scale), posttraumatic growth (Posttraumatic Growth Inventory),
perceived stress (Perceived Stress Scale) and posttraumatic stress (Davidson
Trauma Scale), correlation and regression analyses were conducted. To study its
sensitivity, we assessed the effect of sociodemographics and the ability of the
scale to identify high-risk populations by conducting analyses of variance and
Pearson correlations. The BRS scores showed adequate reliability (α = .83;
intraclass coefficient = .69). Confirmatory factor analyses showed that the
Spanish version of the BRS is mono-factorial (χ2/df = 2.36; standardized root
mean square residual = .036; goodness-of-fit index = .980; comparative fit index
= .984; incremental fit index = .984; root mean square error of approximation =
.067). They also showed adequate evidence of the scores' convergent, concurrent
and predictive validity. The Spanish version of the BRS is a reliable and valid
means to assess resilience as the ability to bounce back. (PsycINFO Database
Record OBJECTIVE: This was a 12-week randomized, placebo-controlled trial to assess the
efficacy of quetiapine monotherapy in the treatment of posttraumatic stress
disorder (PTSD).
METHOD: Eighty patients were randomly assigned to treatment with either
quetiapine or placebo. The primary outcome measure was the
Clinician-Administered PTSD Scale (CAPS). Secondary efficacy measures included
the CAPS subscales, the Davidson Trauma Scale, the Positive and Negative
Syndrome Scale (PANSS), the Clinical Global Impressions (CGI) scales for
severity of Illness and improvement, the Hamilton Depression Rating Scale
(HAM-D), and the Hamilton Anxiety Rating Scale (HAM-A). Safety measurements
included adverse events, vital signs, the Abnormal Involuntary Movement Scale,
the Barnes Akathisia Scale, the Simpson-Angus Scale, and the Arizona Sexual
Experiences Scale.
RESULTS: After a 1-week placebo run-in, quetiapine was started at a daily dosage
of 25 mg and increased to a maximum of 800 mg; the average was 258 mg (range,
50-800 mg). Reductions in CAPS total, re-experiencing, and hyperarousal scores
were significantly greater for the quetiapine group than for the placebo group.
Greater improvements were also observed for quetiapine in scores on the Davidson
Trauma Scale, CGI severity and improvement ratings, PANSS positive symptom and
general psychopathology subscales, HAM-A, and HAM-D than for placebo. Adverse
events were generally mild and expected based on prior studies of quetiapine in
this and other patient population. There were no differences in safety measures
between groups.
CONCLUSION: Quetiapine monotherapy was efficacious in the treatment of PTSD.
These findings suggest quetiapine as a single agent is effective in treating
military PTSD. |
What is the function of the Mis18 protein? | Kinetochores assemble on a specialized chromosomal locus termed the centromere, which is characterized by the replacement of histone H3 in centromeric nucleosomes with the essential histone H3 variant CENP-A (centromere protein A). The Mis18 complex has been identified as a critical factor for the centromeric localization of a histone H3 variant, centromeric protein A (CENP-A), which is responsible for the specification of centromere identity in the chromosome. Further, we demonstrate Mis18α's crucial role for epigenetic regulation of centromeric chromatin by reinforcing centromeric localization of DNMT3A/3B. Mis18α interacts with DNMT3A/3B, and this interaction is critical for maintaining DNA methylation and hence regulating epigenetic states of centromeric chromatin. Together, our findings uncover the functional mechanism of Mis18α and its pivotal role in mammalian cell cycle. The Mis18 complex is a critical player in determining when and where centromeres are built. | Centromeres contain specialized chromatin that includes the centromere-specific
histone H3 variant, spCENP-A/Cnp1. Here we report identification of five fission
yeast centromere proteins, Mis14-18. Mis14 is recruited to kinetochores
independently of CENP-A, and, conversely, CENP-A does not require Mis14 to
associate with centromeres. In contrast, Mis15, Mis16 (strong similarity with
human RbAp48 and RbAp46), Mis17, and Mis18 are all part of the CENP-A
recruitment pathway. Mis15 and Mis17 form an evolutionarily conserved complex
that also includes Mis6. Mis16 and Mis18 form a complex and maintain the
deacetylated state of histones specifically in the central core of centromeres.
Mis16 and Mis18 are the most upstream factors in kinetochore assembly as they
can associate with kinetochores in all kinetochore mutants except for mis18 and
mis16, respectively. RNAi knockdown in human cells shows that Mis16 function is
conserved as RbAp48 and RbAp46 are both required for localization of human
CENP-A. Mis16 and Mis18 are subunits of a protein complex required for incorporation of
the histone H3 variant CenH3 (Cnp1/CENP-A) into centromeric chromatin in
Schizosaccharomyces pombe and mammals. How the Mis16-Mis18 complex performs this
function is unknown. Here, we report that the Mis16-Mis18 complex is required
for centromere localization of Scm3(Sp), a Cnp1-binding protein related to
Saccharomyces cerevisiae Scm3. Scm3(Sp) is required for centromeric localization
of Cnp1, while Scm3(Sp) localizes at centromeres independently of Cnp1. Like the
Mis16-Mis18 complex but unlike Cnp1, Scm3(Sp) dissociates from centromeres
during mitosis. Inactivation of Scm3(Sp) or Mis18 increases centromere
localization of histones H3 and H2A/H2B, which are largely absent from
centromeres in wild-type cells. Whereas S. cerevisiae Scm3 is proposed to
replace histone H2A/H2B in centromeric nucleosomes, the dynamic behavior of S.
pombe Scm3 suggests that it acts as a Cnp1 assembly/maintece factor that
directly mediates the stable deposition of Cnp1 into centromeric chromatin. Centromeres of higher eukaryotes are epigenetically marked by the
centromere-specific CENP-A nucleosome. New CENP-A recruitment requires the
CENP-A histone chaperone HJURP. In this paper, we show that a LacI (Lac
repressor) fusion of HJURP drove the stable recruitment of CENP-A to a LacO (Lac
operon) array at a noncentromeric locus. Ectopically targeted CENP-A chromatin
at the LacO array was sufficient to direct the assembly of a functional
centromere as indicated by the recruitment of the constitutive
centromere-associated network proteins, the microtubule-binding protein NDC80,
and the formation of stable kinetochore-microtubule attachments. An
amino-terminal fragment of HJURP was able to assemble CENP-A nucleosomes in
vitro, demonstrating that HJURP is a chromatin assembly factor. Furthermore,
HJURP recruitment to endogenous centromeres required the Mis18 complex.
Together, these data suggest that the role of the Mis18 complex in CENP-A
deposition is to recruit HJURP and that the CENP-A nucleosome assembly activity
of HJURP is responsible for centromeric chromatin assembly to maintain the
epigenetic mark. Eukaryotic chromosomes segregate by attaching to microtubules of the mitotic
spindle through a chromosomal microtubule binding site called the kinetochore.
Kinetochores assemble on a specialized chromosomal locus termed the centromere,
which is characterized by the replacement of histone H3 in centromeric
nucleosomes with the essential histone H3 variant CENP-A (centromere protein A).
Understanding how CENP-A chromatin is assembled and maintained is central to
understanding chromosome segregation mechanisms. CENP-A nucleosome assembly
requires the Mis18 complex and the CENP-A chaperone HJURP. These factors
localize to centromeres in telophase/G1, when new CENP-A chromatin is assembled.
The mechanisms that control their targeting are unknown. In this paper, we
identify a mechanism for recruiting the Mis18 complex protein M18BP1 to
centromeres. We show that depletion of CENP-C prevents M18BP1 targeting to
metaphase centromeres and inhibits CENP-A chromatin assembly. We find that
M18BP1 directly binds CENP-C through conserved domains in the CENP-C protein.
Thus, CENP-C provides a link between existing CENP-A chromatin and the proteins
required for new CENP-A nucleosome assembly. Ubiquitin E3 ligases including SCF complex are key regulators of cell cycle.
Here, we show that Mis18β, a component of Mis18 complex governing CENP-A
localization, is a new substrate of βTrCP-containing SCF complex. βTrCP
interacted with Mis18β exclusively during interphase but not during mitosis and
mediated proteasomal degradation of Mis18β leading to the inactivation of Mis18
complex during interphase. In addition, uncontrolled stabilization of Mis18β
caused cell death. Together, we propose that βTrCP-mediated regulation of Mis18β
stability is a mechanism to restrict centromere function of Mis18 complex from
late mitosis to early G1 phase. CENP-A is a centromere-specific variant of histone H3 that is required for
accurate chromosome segregation. The fission yeast Schizosaccharomyces pombe and
mammalian Mis16 and Mis18 form a complex essential for CENP-A recruitment to
centromeres. It is unclear, however, how the Mis16-Mis18 complex achieves this
function. Here, we identified, by mass spectrometry, novel fission yeast
centromere proteins Mis19 and Mis20 that directly interact with Mis16 and Mis18.
Like Mis18, Mis19 and Mis20 are localized at the centromeres during interphase,
but not in mitosis. Inactivation of Mis19 in a newly isolated
temperature-sensitive mutant resulted in CENP-A delocalization and massive
chromosome missegregation, whereas Mis20 was dispensable for proper chromosome
segregation. Mis19 might be a bridge component for Mis16 and Mis18. We isolated
extragenic suppressor mutants for temperature-sensitive mis18 and mis19 mutants
and used whole-genome sequencing to determine the mutated sites. We identified
two groups of loss-of-function suppressor mutations in non-sense-mediated mRNA
decay factors (upf2 and ebs1), and in SWI/SNF chromatin-remodeling components
(snf5, snf22 and sol1). Our results suggest that the Mis16-Mis18-Mis19-Mis20
CENP-A-recruiting complex, which is functional in the G1-S phase, may be
counteracted by the SWI/SNF chromatin-remodeling complex and non-sense-mediated
mRNA decay, which may prevent CENP-A deposition at the centromere. CENP-A chromatin forms the foundation for kinetochore assembly.
Replication-independent incorporation of CENP-A at centromeres depends on its
chaperone HJURP(Scm3), and Mis18 in vertebrates and fission yeast. The
recruitment of Mis18 and HJURP(Scm3) to centromeres is cell cycle regulated.
Vertebrate Mis18 associates with Mis18BP1(KNL2), which is critical for the
recruitment of Mis18 and HJURP(Scm3). We identify two novel fission yeast
Mis18-interacting proteins (Eic1 and Eic2), components of the Mis18 complex.
Eic1 is essential to maintain Cnp1(CENP-A) at centromeres and is crucial for
kinetochore integrity; Eic2 is dispensable. Eic1 also associates with
Fta7(CENP-Q/Okp1), Cnl2(Nkp2) and Mal2(CENP-O/Mcm21), components of the
constitutive CCAN/Mis6/Ctf19 complex. No Mis18BP1(KNL2) orthologue has been
identified in fission yeast, consequently it remains unknown how the key
Cnp1(CENP-A) loading factor Mis18 is recruited. Our findings suggest that Eic1
serves a function analogous to that of Mis18BP1(KNL2), thus representing the
functional counterpart of Mis18BP1(KNL2) in fission yeast that connects with a
module within the CCAN/Mis6/Ctf19 complex to allow the temporally regulated
recruitment of the Mis18/Scm3(HJURP) Cnp1(CENP-A) loading factors. The novel
interactions identified between CENP-A loading factors and the CCAN/Mis6/Ctf19
complex are likely to also contribute to CENP-A maintece in other organisms. Author information:
(1)Department of Biochemistry and Molecular Genetics, University of Virginia,
Charlottesville, VA 22901, USA.
(2)Department of Biochemistry and Molecular Genetics, University of Virginia,
Charlottesville, VA 22901, USA; Department of Cell Biology, University of
Virginia, Charlottesville, VA 22901, USA. Electronic address:
[email protected]. Despite having caused one of the greatest medical catastrophies of the last
century through its teratogenic side-effects, thalidomide continues to be an
important agent in the treatment of leprosy and cancer. The protein cereblon,
which forms an E3 ubiquitin ligase compex together with damaged DNA-binding
protein 1 (DDB1) and cullin 4A, has been recently indentified as a primary
target of thalidomide and its C-terminal part as responsible for binding
thalidomide within a domain carrying several invariant cysteine and tryptophan
residues. This domain, which we name CULT (cereblon domain of unknown activity,
binding cellular ligands and thalidomide), is also found in a family of secreted
proteins from animals and in a family of bacterial proteins occurring primarily
in δ-proteobacteria. Its nearest relatives are yippee, a highly conserved
eukaryotic protein of unknown function, and Mis18, a protein involved in the
priming of centromeres for recruitment of CENP-A. Searches for distant homologs
point to an evolutionary relationship of CULT, yippee, and Mis18 to proteins
sharing a common fold, which consists of two four-stranded β-meanders packing at
a roughly right angle and coordinating a zinc ion at their apex. A β-hairpin
inserted into the first β-meander extends across the bottom of the structure
towards the C-terminal edge of the second β-meander, with which it forms a
cradle-shaped binding site that is topologically conserved in all members of
this fold. We name this the β-tent fold for the striking arrangement of its
constituent β-sheets. The fold has internal pseudosymmetry, raising the
possibility that it arose by duplication of a subdomain-sized fragment. The Mis18 proteins (Mis18α, Mis18β, and M18BP1) are pivotal to the deposition of
CENP-A at the centromere during cell cycle progression and are indispensable for
embryonic development. Here, we show that Mis18α is critical for the
proliferation of keratinocytes and stratification of the epidermis. Mice lacking
Mis18α in the epidermis died shortly after birth, showing skin abnormalities
like thin and translucent skin and defective skin barrier functions. The
epidermis of newborn Mis18α-deficient mice lacked distinct stratification and
mature hair follicles, with a reduction in the number of proliferating cells and
increased cell death in the basal layer. Earlier expression of the Cre
recombinase from keratin-14 promoter in the ventral region resulted in earlier
keratinocyte death in the ventral part compared with the dorsal part in the
absence of Mis18α, leading to more severe malformation of the ventral epidermal
layers. As observed in Mis18α-deficient mouse keratinocytes, knockdown of Mis18α
in HaCaT cells caused marked loss of centromeric CENP-A dots and chromosomal
misalignment. Overall, we propose that Mis18α is important for epidermal cell
proliferation and stratification, because it is required for the deposition of
CENP-A at the centromeric nucleosomes. |
Are hepadnaviral minichromosomes free of nucleosomes? | Nucleosomes along viral cccDNA in the minichromosomes are not random but sequence-specifically positioned. | We operationally define two forms of SV40 minichromosomes, a 75S-form, prepared
at low salt concentration, referred to as native minichromosomes, and a
50S-form, obtained after treatment with 0.5 M potassium acetate, the
salt-treated minichromosomes. Both preparations of minichromosomes serve well as
templates for replication in vitro. Their respective replication products are
strikingly different: replicated native minichromosomes contain a densely packed
array of the maximal number of nucleosomes whereas replicated salt-treated
minichromosomes carry, on average, half of the maximal number. We conclude that
in both cases parental nucleosomes are transferred to progeny DNA, and, in
addition, that an assembly of new nucleosomes occurs during the replication of
native minichromosomes. This is apparently due to the presence of a nucleosome
assembly factor as a constituent of native minichromosomes that dissociates upon
treatment with salt. We further show that preparations of minichromosomes
usually contain significant amounts of copurifying hnRNP particles and SV40
virion precursor particles. However, these structures do not detectably affect
the replication and the chromatin assembly reactions. The structure of replicating simian virus 40 (SV40) minichromosomes was studied
by DNA crosslinking with trimethyl-psoralen. The procedure was used both in
vitro with extracted SV40 minichromosomes as well as in vivo with SV40-infected
cells. Both procedures gave essentially the same results. Mature SV40
minichromosomes are estimated to contain about 27 nucleosomes (error +/- 2),
except for those molecules with a nucleosome-free gap, which are interpreted to
contain 25 nucleosomes (error +/- 2). In replicative intermediates, nucleosomes
are present in the unreplicated parental stem with the replication fork possibly
penetrating into the nucleosomal DNA before the histone octamer is removed.
Nucleosomes reassociate on the newly replicated DNA branches at distances from
the branch point of 225 ( +/- 145) nucleotides on the leading strand and of 285(
+/- 120) nucleotides on the lagging strand. In the presence of cycloheximide,
daughter duplexes contained unequal numbers of nucleosomes, supporting
dispersive and random segregation of parental nucleosomes. These were arranged
in clusters with normal nucleosome spacing. We detected a novel type of
interlocked dimer comprising two fully replicated molecules connected by a
single-stranded DNA bridge. We cannot decide whether these dimers represent
hemicatees or whether the two circles are joined by a Holliday-type
structure. The joining site maps within the replication terminus. We propose
that these dimers represent molecules engaged in strand segregation. |
Is Cri Du Chat associated with an expansion of a repeat with in the gene found on chromosome 5? | Cri-du-chat syndrome is a chromosomal disorder caused by a deletion of the short arm of chromosome 5 | A case is reported in which features of pseudohypoparathyroidism were found in
association with the cri du chat syndrome. This association may throw some light
on the localization of the chromosomal abberration which underlies
pseudohypoparathyroidism, since deletion of the short arm of chromosome 5 has
been clearly established in the cri du chat syndrome. A female infant presented at birth with hypotonia, growth retardation,
distinctive facies, multiple congenital anomalies, and a high-pitched mewing cry
characteristic of cri du chat syndrome. Chromosome studies from both peripheral
blood and fibroblasts showed a 46,XX,5p- karyotype. Parental chromosome studies
revealed that the mother carried an apparently balanced pericentric inversion of
one chromosome no. 5, 46,XX,inv(5)(p14q35). Meiotic crossing-over in the mother
within the inverted segment of chromosome 5 gave rise to the unbalanced
karyotype, 46,XX,rec(5)dup q, inv(5)(p14q35)mat in the infant. A small terminal
segment of the long arm of chromosome 5 (q35-pter) is duplicated with a deletion
of the short arm of chromosome 5 (p14-pter), accounting for the features of cri
du chat syndrome. Fewer than 1 in 200 of cri du chat syndrome cases are due to
recombination aneusomy arising from a parental inversion of chromosome 5. Some
of these cases, however, do not have typical cri du chat syndrome, reflecting
significant duplication of 5q material. These cases are reviewed with the
present case, and recombination behaviour leading to chromosome imbalance is
discussed. Cri-du-chat is a well described partial aneusomy resulting from deletion of the
short arm of chromosome 5. The hallmark clinical feature of cri-du-chat, a
high-pitched monochromatic cry, has recently been localized to 5p15.3, separate
from the remaining clinical features of the syndrome, which have been localized
to 5p15.2. Five chromosome 5-specific probes from the latter region, designated
the cri-du-chat critical region (CDCCR), were used to isolate 30 cosmids from
the LANL chromosome 5 specific cosmid library. The 30 framework cosmids were
used in a direct selection with three cDNA sources to isolate an initial set of
expressed sequences. Nine unique cDNAs were found that hybridized to four
discrete sets of cosmids in the CDCCR. The nine cDNAs are novel by sequence
database comparisons, and conservatively represent four transcription units.
More recently, we have also constructed a YAC contig of the CDCCR which spans
approximately 2 Mb. As expected, ESTs derived from the nine novel cDNAs map back
to the contig. Limited expression profiles of these cDNAs have been obtained.
Two cDNAs that map to one discrete set of cosmids have different expression
patterns, suggesting that they represent two different genes and increasing the
number of putative genes to five. Further characterization of these genes and
the estimated 100 additional genes deleted in cri-du-chat should lead to better
diagnostic markers and an understanding of the molecular mechanisms of the
disease. The cri-du-chat syndrome is a contiguous gene syndrome that results from a
deletion of the short arm of chromosome 5 (5p). Patients present with a cat-like
cry at birth, which is usually considered diagnostic of this syndrome.
Additional features of the syndrome include failure to thrive, microcephaly,
hypertelorism, epicanthal folds, hypotonia, and severe mental retardation. We
report on four families in which patients with 5p deletions have only the
characteristic cat-like cry, with normal to mildly delayed development. The
precise locations of the deletions in each family were determined by FISH using
lambda phage and cosmid clones. All of the deletion breakpoints map distal to a
chromosomal region that is implicated with the facial features and severe mental
and developmental delay in the cri-du-chat syndrome. DNA clones mapping in the
chromosomal region associated with the cat-like cry feature will be useful
diagnostic tools. They will allow for the distinction between 5p deletions that
will result in the severe delay observed in most cri-du-chat syndrome patients
and those deletions that result in the isolated cat-like cry feature, which is
associated with a better prognosis. Cri-du-chat is a chromosomal deletion syndrome characterized by partial deletion
of the short arm of chromosome 5. The clinical symptoms include growth and
mental retardation, microcephaly, hypertelorism, epicanthal folds, hypotonia,
and a high-pitched monochromatic cry that is usually considered diagnostic for
the syndrome. Recently, a correlation between clinical features and the extent
of the chromosome 5 deletions has identified two regions of the short arm that
appear to be critical for the abnormal development manifested in this syndrome.
Loss of a small region in 5p15.2 correlates with all of the clinical features of
cri-du-chat with the exception of the cat-like cry, which maps to 5p15.3. Here
we report the construction of a YAC contig that spans the chromosomal region in
5p15.2 that plays a major role in the etiology of the cri-du-chat syndrome. YACs
that span the 2-Mb cri-du-chat critical region have been identified and
characterized. This YAC contig lays the groundwork for the construction of a
transcriptional map of this region and the eventual identification of genes
involved in the clinical features associated with the cri-du-chat syndrome. It
also provides a new diagnostic tool for cri-du-chat in the shape of a YAC clone
that may span the entire critical region. Cri-du-chat is a human contiguous gene deletion syndrome resulting from
hemizygous deletions of chromosome 5p. Here we describe the isolation from
within this interval of the human Semaphorin F (SEMAF) gene, a member of a
family of proteins that has been implicated in axonal pathfinding. The human
SEMAF gene covers at least 10% of the deleted region and defines a new class
within this large gene family characterized by the presence of seven type 1
thrombospondin repeats. Prominent expression of murine semaphorin F (Semaf) was
observed in the mouse brain, consistent with a role for semaphorin F as a
signaling molecule that guides axons or migrating neuronal precursors during
development. The known functions of semaphorins and the interesting pattern of
expression for Semaf suggest that haploinsufficiency for SEMAF may disrupt
normal brain development and might lead to some of the features of Cri-du-chat. Structural variations between great ape and human chromosomes due to pericentric
inversions and translocations have created at apparent controversy during the
reconstruction of hominoid phylogeny. One such variation involves human
chromosome 5, which is equivalent to chromosome 4 in chimpanzee and orangutan
but equivalent to segments of chromosomes 4 and 19 in gorilla. Obviously,
neither banding patterns nor centromeric indecies in these chromosomes match.
The pathological condition of cri du chat syndrome is due to the cytogenetic
deletion of band p15.2 of chromosome 5. Is this region involved during
pericentric inversion of apes chromosome 4? We used a human cosmid probe for cri
du chat syndrome as a phylogenetic marker in search of the aforementioned
question. The genomic sequences for cri du chat syndrome region were conserved
in chimpanzee (PTR4) and orangutan (PPY4) but displayed a positional divergence
in gorilla on chromosome 19(GG019). In addition, we used a human cosmid DNA
probe for DiGeorge syndrome which is located on chromosome 22 band q11.2 and was
conserved within band 23q11.2 in apes. The loci specific human genomic probes
may help to describe the inversions and translocations for other chromosomes. A case of prenatally detected cri du chat syndrome (5p-) is reported.
Amniocentesis was performed following an abnormal ultrasound finding of isolated
moderate bilateral ventriculomegaly. The karyotype showed a terminal deletion of
the short arm of chromosome 5 including the critical region 5p15 for cri du chat
syndrome. This was confirmed by fluorescence in situ hybridisation (FISH).
Isolated mild ventriculomegaly may be a non-specific marker for cri du chat
syndrome. The Cri du Chat syndrome (CdCS) is a genetic disease resulting from a deletion
of variable size occurring on the short arm of chromosome 5 (5p-). The incidence
ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features
are a high-pitched monochromatic cry, microcephaly, broad nasal bridge,
epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor
and mental retardation. Malformations, although not very frequent, may be
present: cardiac, neurological and renal abnormalities, preauricular tags,
syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has
allowed a cytogenetic and phenotypic map of 5p to be defined, even if results
from the studies reported up to now are not completely in agreement.
Genotype-phenotype correlation studies showed a clinical and cytogenetic
variability. The identification of phenotypic subsets associated with a specific
size and type of deletion is of diagnostic and prognostic relevance. Specific
growth and psychomotor development charts have been established. Two genes,
Semaphorin F (SEMAF) and delta-catenin (CTNND2), which have been mapped to the
"critical regions", are potentially involved in cerebral development and their
deletion may be associated with mental retardation in CdCS patients. Deletion of
the telomerase reverse transcriptase (hTERT) gene, localised to 5p15.33, could
contribute to the phenotypic changes in CdCS. The critical regions were recently
refined by using array comparative genomic hybridisation. The cat-like cry
critical region was further narrowed using quantitative polymerase chain
reaction (PCR) and three candidate genes were characterised in this region. The
diagnosis is based on typical clinical manifestations. Karyotype analysis and,
in doubtful cases, FISH analysis will confirm the diagnosis. There is no
specific therapy for CdCS but early rehabilitative and educational interventions
improve the prognosis and considerable progress has been made in the social
adjustment of CdCS patients. Cri-du-chat syndrome is caused by haploinsufficiency of the genes on the distal
part of the short arm of chromosome 5, and characteristic features include
microcephaly, developmental delays, and a distinctive high-pitched mewing cry.
Most cri-du-chat syndrome cases result from a sporadic de novo deletion that is
associated with a low recurrence risk. On rare occasions, however, cri-du-chat
syndrome with 5p monosomy can be accompanied by 5q trisomy. This combination is
virtually always associated with parental large pericentric inversions. Among
previously reported cri-du-chat syndrome cases with 5p monosomy accompanied by
5q trisomy, the aneusomy of chromosome 5 in all but one case was cytogenetically
visible using G-banding. When an accompanying 5q trisomy is detected, a
significant recurrence risk is expected. We here report on a patient with
cri-du-chat syndrome phenotype who initially exhibited a normal karyotype on
G-banding but in whom molecular analysis using multiplex ligation-dependent
probe amplification and array comparative genomic hybridization revealed a 5p
deletion accompanied by a 5q duplication. Parental chromosomal testing led to
the identification of a very large pericentric inversion, of which breakpoints
resided at the terminal regions of 5p15.31 and 5q35.1. This information was
vital for counseling the family regarding the significantly high recurrence
risk. Cri du chat syndrome is characterized by cat-like cry, facial dysmorphisms,
microcephaly, speech delay, intellectual disability and slow growth rate, which
are present with variable frequency. The typical cri du chat syndrome, due to
5p15.2 deletion, includes severe intellectual disability, facial dysmorphisms,
neonatal hypotonia and pre- and post-natal growth retardation, whereas more
distal deletions in 5p15.3 lead to cat-like cry and speech delay and produce the
clinical picture of the atypical cri du chat syndrome, with minimal or absent
intellectual impairment. In this article we report a three-generation family
with an unbalanced whole arm translocation between chromosome 5 and 15 and a
microdeletion of 5.5 Mb involving 5p15.33-32. By reporting the smallest terminal
deletion of 5p15.3 described so far and by reviewing the literature we discuss
the genotype/phenotype correlations of the distal region of the cri du chat
syndrome. The previously described critical region for the speech delay may be
narrowed down and microcephaly, growth retardation and dysmorphic facial
features can be included in the phenotypic expression of the atypical cri du
chat syndrome due to 5p15.3 deletions. Cri-du-chat syndrome is a chromosomal disorder caused by a deletion of the short
arm of chromosome 5. The disease severity, levels of intellectual and
developmental delay, and patient prognosis have been related to the size and
position of the deletion. Aiming to establish genotype-phenotype correlations,
we applied array-CGH to evaluate six patients carrying cytogenetically detected
deletions of the short arm of chromosome 5 who were followed at a genetics
community service. The patients' cytogenetic and clinical profiles were
reevaluated. A database review was performed to predict additional genes and
regulatory elements responsible for the characteristic phenotypic and behavioral
traits of this disorder. Array-CGH analysis allowed for delineation of the
terminal deletions, which ranged in size from approximately 11.2 Mb to 28.6 Mb,
with breakpoints from 5p15.2 to 5p13. An additional dup(8)(p23) (3.5 Mb),
considered to be a benign copy number variation, was also observed in one
patient. The correlation coefficient value (ρ = 0.13) calculated indicated the
presence of a weak relationship between developmental delay and deletion size.
Genetic background, family history, epigenetic factors, quantitative trait locus
polymorphisms, and environmental factors may also affect patient phenotype and
must be taken into account in genotype-phenotype correlations. |
What are the roles of Smyd3 in zebrafish? | Smyd3 is required for the development of cardiac and skeletal muscle in zebrafish. Transcripts of smyd3 are expressed in zebrafish embryos at all developmental stages and knockdown of smyd3 in embryos resulted in pericardial edema and defects in the trunk structure. In addition, these phenotypes are associated with abnormal expression of three heart-chamber markers including cmlc2, amhc and vmhc, and abnormal expression of myogenic regulatory factors including myod and myog. | While increasing evidence indicates the important function of histone
methylation during development, how this process influences cardiac development
in vertebrates has not been explored. Here, we elucidate the functions of two
histone H3 lysine 4 (H3K4) methylation enzymes, SMYD3 and SETD7, during
zebrafish heart morphogenesis using gene expression profiling by whole mount in
situ hybridization and antisense morpholino oligonucleotide (MO)-based gene
knockdown. We find both smyd3 and setd7 are highly expressed within developing
zebrafish heart and knock-down of these genes led to severe defects in cardiac
morphogenesis without altering the expressions pattern of heart markers,
including cmlc2, vmhc, and amhc. Furthermore, double knock-down by coinjection
of smyd3 and setd7 MOs caused the synergistic defects in heart development. As
similar to knock-down effect, overexpression of these genes also caused the
heart morphogenesis defect in zebrafish. These results indicate that histone
modifying enzymes, SMYD3 and SETD7, appear to function synergistically during
heart development and their proper functioning is essential for normal heart
morphogenesis during development. |
Which enzyme is inhibited by ribociclib? | Ribociclib is inhibitor of cyclin D-cyclin-dependent kinase 4/6 (CDK 4/6). It is used for breast cancer treatment. | Acute kidney injury (AKI) is a potentially fatal syndrome characterized by a
rapid decline in kidney function caused by ischemic or toxic injury to renal
tubular cells. The widely used chemotherapy drug cisplatin accumulates
preferentially in the renal tubular cells and is a frequent cause of
drug-induced AKI. During the development of AKI the quiescent tubular cells
reenter the cell cycle. Strategies that block cell-cycle progression ameliorate
kidney injury, possibly by averting cell division in the presence of extensive
DNA damage. However, the early signaling events that lead to cell-cycle
activation during AKI are not known. In the current study, using mouse models of
cisplatin nephrotoxicity, we show that the G1/S-regulating cyclin-dependent
kinase 4/6 (CDK4/6) pathway is activated in parallel with renal cell-cycle entry
but before the development of AKI. Targeted inhibition of CDK4/6 pathway by
small-molecule inhibitors palbociclib (PD-0332991) and ribociclib (LEE011)
resulted in inhibition of cell-cycle progression, amelioration of kidney injury,
and improved overall survival. Of additional significance, these compounds were
found to be potent inhibitors of organic cation transporter 2 (OCT2), which
contributes to the cellular accumulation of cisplatin and subsequent kidney
injury. The unique cell-cycle and OCT2-targeting activities of palbociclib and
LEE011, combined with their potential for clinical translation, support their
further exploration as therapeutic candidates for prevention of AKI. Imbalance of the cyclin D and cyclin-dependent kinase (CDK) pathway in cancer
cells may result in diversion away from a pathway to senescence and toward a
more proliferative phenotype. Cancer cells may increase cyclin D-dependent
activity through a variety of mechanisms. Therapeutic inhibition of CDKs in
tumors to negate their evasion of growth suppressors has been identified as a
key anticancer strategy. In this review, we outline the development of CDK
inhibitory therapy in breast cancer, including the initial experience with the
pan-CDK inhibitor flavopiridol and the next generation of oral highly selective
CDK4 and CDK6 inhibitors PD0332991 (palbociclib), LEE011 (ribociclib), and
LY2835219 (abemaciclib). Data from phase I and II studies in estrogen
receptor-positive (ER+) breast cancer demonstrate promising efficacy with
manageable toxic effects, chiefly neutropenia. We discuss these studies and the
phase III studies that are accruing or nearing completion. We describe the
application of such therapy to other breast cancer settings, including
HER2-positive breast cancer and the adjuvant treatment of early breast cancer.
We also discuss potential concerns surrounding the combination of CDK inhibitors
with chemotherapy and their effects on repair of double-strand DNA breaks in
cancer cells. Oral highly selective CDK inhibitors show great promise in
improving the outcomes of patients with ER+ breast cancer, although caution must
apply to their combination with other agents and in the early breast cancer
setting. For millions of women, breast cancer remains a potentially life-endangering
diagnosis. With advances in research, new therapies targeted to tumor biology
are emerging to treat the most common form of this disease. Cyclin-dependent
kinase (CDK) 4/6 inhibitors are a new class of therapeutic agents that have the
potential to improve the outcomes of patients with hormone receptor-positive
(HR(+)) breast cancer. Three CDK 4/6 inhibitors have been investigated for the
treatment of HR(+) breast cancer, including palbociclib (PD 0332991), ribociclib
(LEE011), and abemaciclib (LY2835219). Palbociclib recently received accelerated
Food and Drug Administration approval for the treatment of HR(+) metastatic
breast cancer in combination with letrozole, and recent data suggest improved
outcome when combined with fulvestrant. In this article, the mechanism of action
of CDK 4/6 inhibitors, preclinical studies on their efficacy, ongoing clinical
trials in breast cancer, and toxicity profiles are reviewed. Several selective CDK4/6 inhibitors are in clinical trials for non-small cell
lung cancer (NSCLC). Palbociclib (PD0332991) is included in the phase II/III
Lung-MAP trial for squamous cell lung carcinoma (LUSQ). We noted differential
cellular activity between palbociclib and the structurally related ribociclib
(LEE011) in LUSQ cells. Applying an unbiased mass spectrometry-based
chemoproteomics approach in H157 cells and primary tumor samples, we here report
distinct proteome-wide target profiles of these two drug candidates in LUSQ,
which encompass novel protein and, for palbociclib only, lipid kinases. In
addition to CDK4 and 6, we observed CDK9 as a potent target of both drugs.
Palbociclib interacted with several kinases not targeted by ribociclib, such as
casein kinase 2 and PIK3R4, which regulate autophagy. Furthermore, palbociclib
engaged several lipid kinases, most notably, PIK3CD and PIP4K2A/B/C.
Accordingly, we observed modulation of autophagy and inhibition of AKT signaling
by palbociclib but not ribociclib. PURPOSE OF REVIEW: In this article, we not only review the preclinical and
clinical studies of cyclin-dependent kinase (CDK) 4/6 inhibitors in breast
cancer, liposarcoma, mantel cell lymphoma, melanoma and germ cell tumors, but
also examine promising preclinical data in glioblastoma, renal and ovarian
cancer models that may provide directions for future development.
RECENT FINDINGS: Targeting CDKs has been the focus of considerable basic science
and clinical research. The CDK 4/6 inhibitors are a novel class of therapeutics
that target the CDK 4/6 kinases that promote transition through the cell cycle.
Currently, palbociclib (PD0332991, Pfizer), abemaciclib (LY2835219, Lilly) and
ribociclib (LEE011, Novartis) are being investigated in clinical trials. These
oral agents offer the hope of clinical efficacy in many tumor types, and have
been associated with minimal toxicity. Amplification/overexpression of cyclin D,
loss of CDKN2A (p16) and amplification/overexpression of CDK4 are proposed
biomarkers of improved response to CDK4/6 inhibition.
SUMMARY: Palbociclib, abemaciclib and ribociclib have demonstrated very
promising clinical activity in breast cancer, liposarcoma, mantel cell lymphoma
and melanoma. Moreover, CDK4/6 inhibitors have shown promising preclinical
activity in glioblastoma, renal and ovarian cancer models that may provide
directions for their future clinical development. Further preclinical and
clinical research is needed to better understand mechanisms of resistance and
develop rational combination therapies with other targeted agents. Dysregulation of the cyclin D-cyclin-dependent kinase (CDK)
4/6-INK4-retinoblastoma (Rb) pathway is an important contributor to endocrine
therapy resistance. Recent clinical development of selective inhibitors of CDK4
and CDK6 kinases has led to renewed interest in cell cycle regulators, following
experience with relatively non-selective pan-CDK inhibitors that often resulted
in limited activity and poor safety profiles in the clinic. The highly selective
oral CDK 4/6 inhibitors palbociclib (PD0332991), ribociclib (LEE011), and
abemaciclib (LY2835219) are able to inhibit the proliferation of Rb-positive
tumor cells and have demonstrated dose-dependent growth inhibition in ER+ breast
cancer models. In metastatic breast cancer, all three agents are being explored
in combination with endocrine therapy in Phase III studies. Results so far
indicated promising efficacy and manageable safety profiles, and led to the FDA
approval of palbociclib. Phase II-III studies of these agents, in combination
with endocrine therapy, are also underway in early breast cancer in the
neoadjuvant and adjuvant settings. Selective CDK 4/6 inhibitors are also being
investigated with other targeted agents or chemotherapy in the advanced setting.
This article reviews the rationale for targeting cyclin D-CDK 4/6 in hormone
receptor-positive (HR+) breast cancer, provides an overview of the available
preclinical and clinical data with CDK 4/6 inhibitors in breast cancer to date,
and summarizes the main features of ongoing clinical trials of these new agents
in breast cancer. Future trials evaluating further combination strategies with
CDK 4/6 backbone and translational studies refining predictive biomarkers are
needed to help personalize the optimal treatment regimen for individual patients
with ER+ breast cancer. The cyclin D-cyclin dependent kinase (CDK) 4/6-inhibitor of CDK4
(INK4)-retinoblastoma (Rb) pathway controls cell cycle progression by regulating
the G1-S checkpoint. Dysregulation of the cyclin D-CDK4/6-INK4-Rb pathway
results in increased proliferation, and is frequently observed in many types of
cancer. Pathway activation can occur through a variety of mechanisms, including
gene amplification or rearrangement, loss of negative regulators, epigenetic
alterations, and point mutations in key pathway components. Due to the
importance of CDK4/6 activity in cancer cells, CDK4/6 inhibitors have emerged as
promising candidates for cancer treatment. Moreover, combination of a CDK4/6
inhibitor with other targeted therapies may help overcome acquired or de novo
treatment resistance. Ongoing studies include combinations of CDK4/6 inhibitors
with endocrine therapy and phosphatidylinositol 3-kinase (PI3K) pathway
inhibitors for hormone receptor-positive (HR+) breast cancers, and with
selective RAF and MEK inhibitors for tumors with alterations in the mitogen
activated protein kinase (MAPK) pathway such as melanoma. In particular, the
combination of CDK4/6 inhibitors with endocrine therapy, such as palbociclib's
recent first-line approval in combination with letrozole, is expected to
transform the treatment of HR+ breast cancer. Currently, three selective CDK4/6
inhibitors have been approved or are in late-stage development: palbociclib
(PD-0332991), ribociclib (LEE011), and abemaciclib (LY2835219). Here we describe
the current preclinical and clinical data for these novel agents and discuss
combination strategies with other agents for the treatment of cancer. Uncontrolled cellular proliferation, mediated by dysregulation of the cell-cycle
machinery and activation of cyclin-dependent kinases (CDKs) to promote
cell-cycle progression, lies at the heart of cancer as a pathological process.
Clinical implementation of first-generation, nonselective CDK inhibitors,
designed to inhibit this proliferation, was originally hampered by the high risk
of toxicity and lack of efficacy noted with these agents. The emergence of a new
generation of selective CDK4/6 inhibitors, including ribociclib, abemaciclib and
palbociclib, has enabled tumour types in which CDK4/6 has a pivotal role in the
G1-to-S-phase cell-cycle transition to be targeted with improved effectiveness,
and fewer adverse effects. Results of pivotal phase III trials investigating
palbociclib in patients with advanced-stage oestrogen receptor (ER)-positive
breast cancer have demonstrated a substantial improvement in progression-free
survival, with a well-tolerated toxicity profile. Mechanisms of acquired
resistance to CDK4/6 inhibitors are beginning to emerge that, although
unwelcome, might enable rational post-CDK4/6 inhibitor therapeutic strategies to
be identified. Extending the use of CDK4/6 inhibitors beyond ER-positive breast
cancer is challenging, and will likely require biomarkers that are predictive of
a response, and the use of combination therapies in order to optimize CDK4/6
targeting. Treatment of metastatic breast cancer (MBC) that is resistant to endocrine
therapy presents a significant clinical challenge. The well-known role of cell
cycle dysregulation in these patients is partly mediated by cyclin-dependent
kinase (CDK) activity. Specific cyclin and CDK complexes regulate cell cycle
progression by managing the transition through the cell cycle, and inhibition of
CDKs represents an important target for novel agents. First-generation CDK
inhibitors (e.g., flavopiridol) were relatively nonselective and had an
unacceptable toxicity profile in early trials. Second-generation CDK inhibitors
were designed to target the CDK4 and CDK6 (CDK4/6) pathway and have shown
promising clinical activity with an acceptable toxicity profile in patients with
MBC. Palbociclib is a first-in-class CDK4/6 inhibitor that was granted
accelerated U.S. Food and Drug Administration approval in combination with
letrozole for the treatment of MBC in the first-line setting (February 2015) as
well as in combination with fulvestrant for MBC that had progressed on previous
endocrine therapy (February 2016). Other CDK4/6 inhibitors, including ribociclib
and abemaciclib, are under investigation as monotherapy and in combination with
endocrine or anti-human epidermal growth receptor 2 therapy for the treatment of
MBC. Ongoing clinical trials should provide additional information to guide the
appropriate use of these agents and identify patient populations that could
derive the most benefit. OBJECTIVES: Cyclin D-cyclin-dependent kinase (CDK) 4/6-inhibitor of
CDK4/6-retinoblastoma (Rb) pathway hyperactivation is associated with hormone
receptor-positive (HR+) breast cancer (BC). This study assessed the biological
activity of ribociclib (LEE011; CDK4/6 inhibitor) plus letrozole compared with
single-agent letrozole in the presurgical setting.
MATERIALS AND METHODS: Postmenopausal women (N = 14) with resectable, HR+, human
epidermal growth factor receptor 2-negative (HER2-) early BC were randomized
1:1:1 to receive 2.5 mg/day letrozole alone (Arm 1), or with 400 or 600 mg/day
ribociclib (Arm 2 or 3). Circulating tumor DNA and tumor biopsies were collected
at baseline and, following 14 days of treatment, prior to or during surgery. The
primary objective was to assess antiproliferative response per Ki67 levels in
Arms 2 and 3 compared with Arm 1. Additional assessments included safety,
pharmacokinetics, and genetic profiling.
RESULTS: Mean decreases in the Ki67-positive cell fraction from baseline were:
Arm 1 69% (range 38-100%; n = 2), Arm 2 96% (range 78-100%; n = 6), Arm 3 92%
(range 75-100%; n = 3). Decreased phosphorylated Rb levels and CDK4, CDK6,
CCND2, CCND3, and CCNE1 gene expression were observed following ribociclib
treatment. Ribociclib and letrozole pharmacokinetic parameters were consistent
with single-agent data. The ribociclib plus letrozole combination was well
tolerated, with no Grade 3/4 adverse events over the treatment.
CONCLUSION: The results suggest absence of a drug-drug interaction between
ribociclib and letrozole and indicate ribociclib plus letrozole may reduce Ki67
expression in HR+, HER2- BC (NCT01919229). PURPOSE: Ribociclib (an oral, highly specific cyclin-dependent kinase 4/6
inhibitor) inhibits tumor growth in preclinical models with intact
retinoblastoma protein (Rb+). This first-in-human study investigated the MTD,
recommended dose for expansion (RDE), safety, preliminary activity,
pharmacokinetics, and pharmacodynamics of ribociclib in patients with Rb+
advanced solid tumors or lymphomas.
EXPERIMENTAL DESIGN: Patients received escalating doses of ribociclib
(3-weeks-on/1-week-off or continuous). Dose escalation was guided by a Bayesian
Logistic Regression Model with overdose control principle.
RESULTS: Among 132 patients, 125 received ribociclib 3-weeks-on/1-week-off and 7
were dosed continuously. Nine dose-limiting toxicities were observed among 70
MTD/RDE evaluable patients during cycle 1, most commonly neutropenia (n = 3) and
thrombocytopenia (n = 2). The MTD and RDE were established as 900 and 600 mg/day
3-weeks-on/1-week-off, respectively. Common treatment-related adverse events
were (all-grade; grade 3/4) neutropenia (46%; 27%), leukopenia (43%; 17%),
fatigue (45%; 2%), and nausea (42%; 2%). Asymptomatic Fridericia's corrected QT
prolongation was specific to doses ≥600 mg/day (9% of patients at 600 mg/day;
33% at doses >600 mg/day). Plasma exposure increases were slightly higher than
dose proportional; mean half-life at the RDE was 32.6 hours. Reduced Ki67 was
observed in paired skin and tumor biopsies, consistent with ribociclib-mediated
antiproliferative activity. There were 3 partial responses and 43 patients
achieved a best response of stable disease; 8 patients were progression-free for
>6 months.
CONCLUSIONS: Ribociclib demonstrated an acceptable safety profile,
dose-dependent plasma exposure, and preliminary signs of clinical activity.
Phase I-III studies of ribociclib are under way in various indications. Clin
Cancer Res; 22(23); 5696-705. ©2016 AACR. BACKGROUND: The inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6) could
potentially overcome or delay resistance to endocrine therapy in advanced breast
cancer that is positive for hormone receptor (HR) and negative for human
epidermal growth factor receptor 2 (HER2).
METHODS: In this randomized, placebo-controlled, phase 3 trial, we evaluated the
efficacy and safety of the selective CDK4/6 inhibitor ribociclib combined with
letrozole for first-line treatment in 668 postmenopausal women with HR-positive,
HER2-negative recurrent or metastatic breast cancer who had not received
previous systemic therapy for advanced disease. We randomly assigned the
patients to receive either ribociclib (600 mg per day on a 3-weeks-on,
1-week-off schedule) plus letrozole (2.5 mg per day) or placebo plus letrozole.
The primary end point was investigator-assessed progression-free survival.
Secondary end points included overall survival, overall response rate, and
safety. A preplanned interim analysis was performed on January 29, 2016, after
243 patients had disease progression or died. Prespecified criteria for
superiority required a hazard ratio of 0.56 or less with P<1.29×10-5.
RESULTS: The duration of progression-free survival was significantly longer in
the ribociclib group than in the placebo group (hazard ratio, 0.56; 95% CI, 0.43
to 0.72; P=3.29×10-6 for superiority). The median duration of follow-up was 15.3
months. After 18 months, the progression-free survival rate was 63.0% (95%
confidence interval [CI], 54.6 to 70.3) in the ribociclib group and 42.2% (95%
CI, 34.8 to 49.5) in the placebo group. In patients with measurable disease at
baseline, the overall response rate was 52.7% and 37.1%, respectively (P<0.001).
Common grade 3 or 4 adverse events that were reported in more than 10% of the
patients in either group were neutropenia (59.3% in the ribociclib group vs.
0.9% in the placebo group) and leukopenia (21.0% vs. 0.6%); the rates of
discontinuation because of adverse events were 7.5% and 2.1%, respectively.
CONCLUSIONS: Among patients receiving initial systemic treatment for
HR-positive, HER2-negative advanced breast cancer, the duration of
progression-free survival was significantly longer among those receiving
ribociclib plus letrozole than among those receiving placebo plus letrozole,
with a higher rate of myelosuppression in the ribociclib group. (Funded by
Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT01958021 .). Purpose: Neuroblastoma is treated with aggressive multimodal therapy, yet more
than 50% of patients experience relapse. We recently showed that relapsed
neuroblastomas frequently harbor mutations leading to hyperactivated ERK
signaling and sensitivity to MEK inhibition therapy. Here we sought to define a
synergistic therapeutic partner to potentiate MEK inhibition.Experimental
Design: We first surveyed 22 genetically annotated human neuroblastoma-derived
cell lines (from 20 unique patients) for sensitivity to the MEK inhibitor
binimetinib. After noting an inverse correlation with sensitivity to ribociclib
(CDK4/6 inhibitor), we studied the combinatorial effect of these two agents
using proliferation assays, cell-cycle analysis, Ki67 immunostaining, time-lapse
microscopy, and xenograft studies.Results: Sensitivity to binimetinib and
ribociclib was inversely related (r = -0.58, P = 0.009). MYCN amplification
status and expression were associated with ribociclib sensitivity and
binimetinib resistance, whereas increased MAPK signaling was the main
determit of binimetinib sensitivity and ribociclib resistance. Treatment with
both compounds resulted in synergistic or additive cellular growth inhibition in
all lines tested and significant inhibition of tumor growth in three of four
xenograft models of neuroblastoma. The augmented growth inhibition was
attributed to diminished cell-cycle progression that was reversible upon removal
of drugs.Conclusions: Here we demonstrate that combined binimetinib and
ribociclib treatment shows therapeutic synergy across a broad panel of high-risk
neuroblastoma preclinical models. These data support testing this combination
therapy in relapsed high-risk neuroblastoma patients, with focus on cases with
hyperactivated RAS-MAPK signaling. Clin Cancer Res; 23(7); 1785-96. ©2016 AACR. The combination of antiestrogen therapy and ribociclib, an investigational
CDK4/6 inhibitor, led to improved outcomes in women with metastatic HR-positive,
HER2-negative breast cancer, according to findings presented at a meeting of the
European Society for Medical Oncology. The combination significantly increased
progression-free survival compared with letrozole alone in a large phase III
trial-data that could lead to FDA approval. |
Which histone mutations have been associated with pediatric gliomas? | About 80% of Diffuse intrinsic pontine glioma (DIPG) cases and 70% of midline glioblastomas contain a mutation at one allele of the H3F3A gene (encoding histone H3 variant H3.3), replacing the lysine 27 with methionine (K27M). Moreover, approximately 30% of pediatric high grade gliomas (pedHGG) including GBM and DIPG harbor a lysine 27 mutation (K27M) in histone 3.3 (H3.3) which is correlated with poor outcome. Recent studies on high-grade pediatric GBM have identified two recurrent mutations (K27M and G34R/V) in genes encoding histone H3 (H3F3A for H3.3 and HIST1H3B for H3.1) | Recurrent mutations affecting the histone H3.3 residues Lys27 or indirectly
Lys36 are frequent drivers of pediatric high-grade gliomas (over 30% of HGGs).
To identify additional driver mutations in HGGs, we investigated a cohort of 60
pediatric HGGs using whole-exome sequencing (WES) and compared them to 543
exomes from non-cancer control samples. We identified mutations in SETD2, a
H3K36 trimethyltransferase, in 15% of pediatric HGGs, a result that was
genome-wide significant (FDR = 0.029). Most SETD2 alterations were truncating
mutations. Sequencing the gene in this cohort and another validation cohort (123
gliomas from all ages and grades) showed SETD2 mutations to be specific to
high-grade tumors affecting 15% of pediatric HGGs (11/73) and 8% of adult HGGs
(5/65) while no SETD2 mutations were identified in low-grade diffuse gliomas
(0/45). Furthermore, SETD2 mutations were mutually exclusive with H3F3A
mutations in HGGs (P = 0.0492) while they partly overlapped with IDH1 mutations
(4/14), and SETD2-mutant tumors were found exclusively in the cerebral
hemispheres (P = 0.0055). SETD2 is the only H3K36 trimethyltransferase in
humans, and SETD2-mutant tumors showed a substantial decrease in H3K36me3 levels
(P < 0.001), indicating that the mutations are loss-of-function. These data
suggest that loss-of-function SETD2 mutations occur in older children and young
adults and are specific to HGG of the cerebral cortex, similar to the H3.3
G34R/V and IDH mutations. Taken together, our results suggest that mutations
disrupting the histone code at H3K36, including H3.3 G34R/V, IDH1 and/or SETD2
mutations, are central to the genesis of hemispheric HGGs in older children and
young adults. Sequencing of pediatric gliomas has identified missense mutations Lys27Met
(K27M) and Gly34Arg/Val (G34R/V) in genes encoding histone H3.3 (H3F3A) and H3.1
(HIST3H1B). We report that human diffuse intrinsic pontine gliomas (DIPGs)
containing the K27M mutation display significantly lower overall amounts of H3
with trimethylated lysine 27 (H3K27me3) and that histone H3K27M transgenes are
sufficient to reduce the amounts of H3K27me3 in vitro and in vivo. We find that
H3K27M inhibits the enzymatic activity of the Polycomb repressive complex 2
through interaction with the EZH2 subunit. In addition, transgenes containing
lysine-to-methionine substitutions at other known methylated lysines (H3K9 and
H3K36) are sufficient to cause specific reduction in methylation through
inhibition of SET-domain enzymes. We propose that K-to-M substitutions may
represent a mechanism to alter epigenetic states in a variety of pathologies. Recent studies have identified a Lys 27-to-methionine (K27M) mutation at one
allele of H3F3A, one of the two genes encoding histone H3 variant H3.3, in 60%
of high-grade pediatric glioma cases. The median survival of this group of
patients after diagnosis is ∼1 yr. Here we show that the levels of H3K27 di- and
trimethylation (H3K27me2 and H3K27me3) are reduced globally in H3.3K27M patient
samples due to the expression of the H3.3K27M mutant allele. Remarkably, we also
observed that H3K27me3 and Ezh2 (the catalytic subunit of H3K27
methyltransferase) at chromatin are dramatically increased locally at hundreds
of gene loci in H3.3K27M patient cells. Moreover, the gain of H3K27me3 and Ezh2
at gene promoters alters the expression of genes that are associated with
various cancer pathways. These results indicate that H3.3K27M mutation
reprograms epigenetic landscape and gene expression, which may drive
tumorigenesis. Glioblastoma (GBM) is the most aggressive primary brain tumor in human. Recent
studies on high-grade pediatric GBM have identified two recurrent mutations
(K27M and G34R/V) in genes encoding histone H3 (H3F3A for H3.3 and HIST1H3B for
H3.1). The two histone H3 mutations are mutually exclusive and give rise to
tumors in different brain compartments. Recently, we and others have shown that
the histone H3 K27M mutation specifically altered the di- and tri-methylation of
endogenous histone H3 at Lys27. Genome-wide studies using ChIP-seq on H3.3K27M
patient samples indicate a global reduction of H3K27me3 on chromatin.
Remarkably, we also found a dramatic enrichment of H3K27me3 and EZH2 (the
catalytic subunit H3K27 methyltransferase) at hundreds of gene loci in H3.3K27M
patient cells. Here, we discuss potential mechanisms whereby H3K27me3 is
enriched at chromatin loci in cells expressing the H3.3K27M mutation and report
effects of Lys-to-Met mutations of other well-studied lysine residues of histone
H3.1/H3.3 and H4 on the corresponding endogenous lysine methylation. We suggest
that mutation(s) on histones may be found in a variety of human diseases, and
the expression of mutant histones may help to address the function of histone
lysine methylation and possibly other modifications in mammalian cells. INTRODUCTION: Mutations in H3F3A, which encodes histone H3.3, commonly occur in
pediatric glioblastoma. Additionally, H3F3A K27M substitutions occur in gliomas
that arise at midline locations (eg, pons, thalamus, spine); moreover, this
substitution occurs mainly in tumors in children and adolescents. Here, we
sought to determine the association between H3F3A mutations and adult thalamic
glioma.
METHODS: Genomic H3F3A was sequenced from 20 separate thalamic gliomas.
Additionally, for 14 of the 20 gliomas, 639 genes--including cancer-related
genes and chromatin-modifier genes--were sequenced, and the Infinium
HumanMethylation450K BeadChip was used to examine DNA methylation across the
genome.
RESULTS: Of the 20 tumors, 18 were high-grade thalamic gliomas, and of these 18,
11 were from patients under 50 years of age (median age, 38 y; range, 17-46),
and 7 were from patients over 50 years of age. The H3F3A K27M mutation was
present in 10 of the 11 (91%) younger patients and absent from all 7 older
patients. Additionally, H3F3A K27M was not detected in the 2 diffuse
astrocytomas. Further sequencing revealed recurrent mutations in TP53, ATRX,
NF1, and EGFR. Gliomas with H3F3A K27M from pediatric or young adult patients
had similar, characteristic DNA methylation profiles. In contrast, thalamic
gliomas with wild-type H3F3A had DNA methylation profiles similar to those of
hemispheric glioblastomas.
CONCLUSION: We found that high-grade thalamic gliomas from young adults, like
those from children and adolescents, frequently had H3F3A K27M. Histone H3 lysine(27)-to-methionine (H3K27M) gain-of-function mutations occur in
highly aggressive pediatric gliomas. We established a Drosophila animal model
for the pathogenic histone H3K27M mutation and show that its overexpression
resembles polycomb repressive complex 2 (PRC2) loss-of-function phenotypes,
causing derepression of PRC2 target genes and developmental perturbations.
Similarly, an H3K9M mutant depletes H3K9 methylation levels and suppresses
position-effect variegation in various Drosophila tissues. The histone H3K9
demethylase KDM3B/JHDM2 associates with H3K9M-containing nucleosomes, and its
misregulation in Drosophila results in changes of H3K9 methylation levels and
heterochromatic silencing defects. We have established histone
lysine-to-methionine mutants as robust in vivo tools for inhibiting methylation
pathways that also function as biochemical reagents for capturing site-specific
histone-modifying enzymes, thus providing molecular insight into chromatin
signaling pathways. Pediatric glioblastomas (GBM) are highly aggressive and lethal tumors. Recent
sequencing studies have shown that ~30 % of pediatric GBM and ~80 % of diffuse
intrinsic pontine gliomas show K27M mutations in the H3F3A gene, a variant
encoding histone H3.3. H3F3A K27M mutations lead to global reduction in
H3K27me3. Our goal was to develop biomarkers for the histopathologic detection
of these tumors. Therefore, we evaluated the utility of measuring H3K27me3
global reduction as a histopathologic and prognostic biomarker and tested an
antibody directed specifically against the H3.3 K27M mutation in 290 samples.
The study cohort included 203 pediatric (including 38 pediatric high-grade
astrocytomas) and 38 adult brain tumors of various subtypes and grades and 49
non-neoplastic reactive brain tissues. Detection of H3.3 K27M by
immunohistochemistry showed 100 % sensitivity and specificity and was superior
to global reduction in H3K27me3 as a biomarker in diagnosing H3F3A K27M
mutations. Moreover, cases that stained positive for H3.3 K27M showed a
significantly poor prognosis compared to corresponding negative tumors. These
results suggest that immunohistochemical detection of H3.3 K27M is a sensitive
and specific surrogate for the H3F3A K27M mutation and defines a prognostically
poor subset of pediatric GBM. Brain tumors are the most common solid tumors in children. Pediatric high-grade
glioma (HGG) accounts for ∼8-12 % of these brain tumors and is a devastating
disease as 70-90 % of patients die within 2 years of diagnosis. The failure to
advance therapy for these children over the last 30 years is largely due to
limited knowledge of the molecular basis for these tumors and a lack of disease
models. Recently, sequencing of tumor cells revealed that histone H3 is
frequently mutated in pediatric HGG, with up to 78 % of diffuse intrinsic
pontine gliomas (DIPGs) carrying K27M and 36 % of non-brainstem gliomas carrying
either K27M or G34R/V mutations. Although mutations in many chromatin modifiers
have been identified in cancer, this was the first demonstration that histone
mutations may be drivers of disease. Subsequent studies have identified
high-frequency mutation of histone H3 to K36M in chondroblastomas and to G34W/L
in giant cell tumors of bone, which are diseases of adolescents and young
adults. Interestingly, the G34 mutations, the K36M mutations, and the majority
of K27M mutations occur in genes encoding the replacement histone H3.3. Here, we
review the peculiar characteristics of histone H3.3 and use this information as
a backdrop to highlight current thinking about how the identified mutations may
contribute to disease development. Diffuse intrinsic pontine glioma (DIPG) is an aggressive pediatric brain tumor
with a median survival of 1 year after diagnosis. It has been reported recently
that about 80% of DIPG cases and 70% of midline glioblastomas contain a mutation
at one allele of the H3F3A gene (encoding histone H3 variant H3.3), replacing
the lysine 27 with methionine (K27M). In order to facilitate diagnosis of DIPG
patients, a quick and reliable method to identify the H3F3A K27M mutation is
needed. Here, we describe a real-time PCR-based procedure involving a
mutant-specific primer, a blocker oligonucleotide, and a reverse primer that can
differentiate samples with H3F3A K27M mutation from those that do not. We first
tested four different mutant-specific primers for their ability to selectively
amplify H3F3A K27M-mutant allele and found that one primer amplified the mutant
allele more efficiently than the rest. We then determined the optimal
concentration of blocker oligo that significantly improved amplification of the
H3F3A K27M-mutant allele. Using this optimized real-time PCR assay, we analyzed
eleven samples, two of which containing H3F3A K27M mutation, and found that
these two samples were differentially amplified from the nine others. In
addition, we were able to discern the H3F3A K27M mutation in a newly obtained
pediatric brainstem glioblastoma sample whose H3.3 status was not known
previously, and in three other DIPG samples as well as paraffin embedded
samples. These results demonstrate that we have developed a new reliable
procedure for detecting the H3F3A K27M mutation in pediatric glioblastoma
patient samples. Author information:
(1)Department of Human Genetics, McGill University, Montreal, Québec, Canada H3A
1B1.
(2)McGill University and Génome Québec Innovation Centre, Montreal, Québec,
Canada H3A 0G1.
(3)Research Center for Genetic Medicine, Children's National Health System,
Washington, District Of Columbia 20010, USA.
(4)Institute for Biomedical Sciences, George Washington University School of
Medicine and Health Sciences, Washington, District Of Columbia 20052, USA.
(5)Department of Pediatrics, McGill University and McGill University Heath
Centre Research Institute, Montreal, Québec, Canada H4A 3J1.
(6)Division of Pathology, Children's National Health System, Washington,
District Of Columbia 20010, USA.
(7)Center for Cancer and Blood Disorders, Children's National Health System,
Washington, District Of Columbia 20010, USA.
(8)The Department of Neurological Surgery, George Washington University School
of Medicine and Health Sciences, Washington, District Of Columbia 20052, USA.
(9)Center for Molecular Oncologic Pathology, Department of Medical Oncology,
Dana-Farber Cancer Institute, Boston, Massachusett 02115, USA.
(10)Department of Pathology, CHU Ste-Justine, Université de Montréal, Montreal,
Québec, Canada H3T 1C5.
(11)UQ Child Health Research Centre, The University of Queensland, Brisbane,
Queensland 4101, Australia.
(12)University of Queensland Diamantina Institute, The University of Queensland,
Brisbane, Queensland 4102, Australia.
(13)Oncology Service, Children's Health Queensland Hospital and Health Service,
Brisbane, Queensland 4101, Australia.
(14)National Cancer Institute, National Institute of Health, Bethesda, Maryland
20892, USA.
(15)Department of Pathology, Montreal Neurological Hospital, McGill University,
Montreal, Québec, Canada H3A 2B4.
(16)Brain Tumour Institute, Center for Neuroscience and Behavioral Medicine,
Children's National Health System, Washington, District Of Columbia, 20010, USA.
(17)Department of Integrative Systems Biology, George Washington University
School of Medicine and Health Sciences, Washington, District Of Columbia 20052,
USA. BACKGROUND: Glioblastoma multiforme (GBM) and diffuse intrinsic pontine glioma
(DIPG) belong to the most aggressive cancers in children with poor prognosis and
limited therapeutic options. Therapeutic targeting of epigenetic proteins may
offer new treatment options. Preclinical studies identified Enhancer of Zeste
Homolog 2 (EZH2) within polycomb repressor complex 2 (PRC2) as a potential
epigenetic anti-tumor target in adult GBM cells but similar inhibition studies
in pediatric GBM/DIPG were still missing. Moreover, approximately 30% of
pediatric high grade gliomas (pedHGG) including GBM and DIPG harbor a lysine 27
mutation (K27M) in histone 3.3 (H3.3) which is correlated with poor outcome and
was shown to influence EZH2 function.
PATIENTS, MATERIALS AND METHODS: The present study investigated the correlation
of expression of EZH2 and other PRC2 genes (EZH1, SUZ12, EED) with overall
survival of pediatric GBM patients and the cytotoxic impact of EZH2 inhibition
by the novel agent Tazemetostat in pediatric GBM/DIPG cells harboring either a
H3.3 mutation or a H3 wildtype.
RESULTS: EZH2 gene expression does not correlate with survival of pedHGG
patients, and EZH2 inhibition does not induce significant cytotoxicity in pedHGG
cells independently of H3.3 mutations.
DISCUSSION AND CONCLUSION: We suggest that EZH2 inhibition might not offer an
effective single agent treatment option for paedHGG patients. However, the
therapeutic efficacy in combination with cytotoxic and/or other epigenetically
active agents still has to be elucidated. Gliomas represent the most common primary intraparenchymal tumors of the central
nervous system in adults and children and are a genetic and phenotypic
heterogeneous group. Large multi-institutional studies and The Cancer Genome
Atlas have provided firm insights into the basic genetic drivers in gliomas. The
main molecular biomarkers routinely applied to evaluate diffuse gliomas include
MGMT promoter methylation, EGFR alterations (eg, EGFRvIII), IDH1 or IDH2
mutations, and 1p19q co-deletion. Many of these markers have become standard of
care for molecular testing and prerequisites for clinical trial enrollment.
Other recent biomarkers include TERT promoter and ATRX mutations, alterations
that identify specific molecular subgroups of diffuse gliomas with biological
and clinical relevance. It has also become apparent that distinctive patterns of
molecular genetic evolution develop in the context of current therapeutic
regimens. Important insights have also been uncovered in the field of pediatric
glioma, including the identification of recurrent mutation, fusion, and/or
duplication events of the BRAF, FGFR1, MYB, and MYBL1 genes in pediatric
low-grade gliomas, mutations affecting histone components (H3F3A p.K27M or
p.G34) in pediatric high-grade gliomas, and aggressive subsets developing in
midline central nervous system structures. Here, we summarize current concepts
in molecular testing for glial tumors, including recent findings by large-scale
discovery efforts and technologic advances that are affecting routine diagnostic
work. |
Is it feasible to obtain DNA read lengths that exceed 30 Kb? | The emergence and development of so called third generation sequencing platforms such as PacBio has permitted exceptionally long reads (over 20 kb) to be generated but not yet read length >30 Kb. | During the past decade, DNA sequencing output has been mostly dominated by the
second generation sequencing platforms which are characterized by low cost, high
throughput and shorter read lengths for example, Illumina. The emergence and
development of so called third generation sequencing platforms such as PacBio
has permitted exceptionally long reads (over 20 kb) to be generated. Due to read
length increases, algorithm improvements and hybrid assembly approaches, the
concept of one chromosome, one contig and automated finishing of microbial
genomes is now a realistic and achievable task for many microbial laboratories.
In this paper, we describe high quality sequence datasets which span three
generations of sequencing technologies, containing six types of data from four
NGS platforms and originating from a single microorganism, Clostridium
autoethanogenum. The dataset reported here will be useful for the scientific
community to evaluate upcoming NGS platforms, enabling comparison of existing
and novel bioinformatics approaches and will encourage interest in the
development of innovative experimental and computational methods for NGS data. MOTIVATION: Single-molecule, real-time sequencing (SMRT) developed by Pacific
BioSciences produces longer reads than secondary generation sequencing
technologies such as Illumina. The long read length enables PacBio sequencing to
close gaps in genome assembly, reveal structural variations, and identify gene
isoforms with higher accuracy in transcriptomic sequencing. However, PacBio data
has high sequencing error rate and most of the errors are insertion or deletion
errors. During alignment-based homology search, insertion or deletion errors in
genes will cause frameshifts and may only lead to marginal alignment scores and
short alignments. As a result, it is hard to distinguish true alignments from
random alignments and the ambiguity will incur errors in structural and
functional annotation. Existing frameshift correction tools are designed for
data with much lower error rate and are not optimized for PacBio data. As an
increasing number of groups are using SMRT, there is an urgent need for
dedicated homology search tools for PacBio data.
RESULTS: In this work, we introduce Frame-Pro, a profile homology search tool
for PacBio reads. Our tool corrects sequencing errors and also outputs the
profile alignments of the corrected sequences against characterized protein
families. We applied our tool to both simulated and real PacBio data. The
results showed that our method enables more sensitive homology search,
especially for PacBio data sets of low sequencing coverage. In addition, we can
correct more errors when comparing with a popular error correction tool that
does not rely on hybrid sequencing.
AVAILABILITY AND IMPLEMENTATION: The source code is freely available at
https://sourceforge.net/projects/frame-pro/
CONTACT: [email protected]. De novo sequencing of complex genomes is one of the main challenges for
researchers seeking high-quality reference sequences. Many de novo assemblies
are based on short reads, producing fragmented genome sequences.
Third-generation sequencing, with read lengths >10 kb, will improve the assembly
of complex genomes, but these techniques require high-molecular-weight genomic
DNA (gDNA), and gDNA extraction protocols used for obtaining smaller fragments
for short-read sequencing are not suitable for this purpose. Methods of
preparing gDNA for bacterial artificial chromosome (BAC) libraries could be
adapted, but these approaches are time-consuming, and commercial kits for these
methods are expensive. Here, we present a protocol for rapid, inexpensive
extraction of high-molecular-weight gDNA from bacteria, plants, and animals. Our
technique was validated using sunflower leaf samples, producing a mean read
length of 12.6 kb and a maximum read length of 80 kb. |
Is osteocrin expressed exclusively in the bone? | No, Osteocrin (Ostn) has been detected in the bones and the brain. | Osteocrin (Ostn), a bone-active molecule, has been shown in animals to be highly
expressed in cells of the osteoblast lineage. We have characterized this protein
in human cultured primary human osteoblasts, in developing human neonatal bone,
and in iliac crest bone biopsies from adult women. In vivo, Ostn expression was
localized in developing human neonatal rib bone, with intense immunoreactivity
in osteoblasts on bone-forming surfaces, in newly incorporated osteocytes, and
in some late hypertrophic chondrocytes. In adult bone, Ostn expression was
specifically localized to osteoblasts and young osteocytes at bone-forming
sites. In vitro, Ostn expression decreased time dependently (p<0.02) in
osteoblasts cultured for 2, 3, and 6 days. Expression was further decreased in
cultures containing 200 nM hydrocortisone by 1.5-, 2.3-, and 3.1-fold (p<0.05)
at the same time points. In contrast, alkaline phosphatase expression increased
with osteoblast differentiation (p<0.05). Low-dose estradiol decreased Ostn
expression time dependently (p<0.05), whereas Ostn expression in cultures
treated with high-dose estradiol was not significantly changed. These results
demonstrate that Ostn is expressed in human skeletal tissue, particularly in
osteoblasts in developing bone and at sites of bone remodeling, suggesting a
role in bone formation. Thus, Ostn provides a marker of osteoblast lineage cells
and appears to correlate with osteoblast activity. Sensory stimuli drive the maturation and function of the mammalian nervous
system in part through the activation of gene expression networks that regulate
synapse development and plasticity. These networks have primarily been studied
in mice, and it is not known whether there are species- or clade-specific
activity-regulated genes that control features of brain development and
function. Here we use transcriptional profiling of human fetal brain cultures to
identify an activity-dependent secreted factor, Osteocrin (OSTN), that is
induced by membrane depolarization of human but not mouse neurons. We find that
OSTN has been repurposed in primates through the evolutionary acquisition of DNA
regulatory elements that bind the activity-regulated transcription factor MEF2.
In addition, we demonstrate that OSTN is expressed in primate neocortex and
restricts activity-dependent dendritic growth in human neurons. These findings
suggest that, in response to sensory input, OSTN regulates features of neuronal
structure and function that are unique to primates. |
What is Achondroplasia? | Achondrogenesis type II also known as Achondroplasia is an autosomal-dominant disease leading to severe micromelic dwarfism | Fibroblast growth factor receptor 3 (FGFR3) is a receptor tyrosine kinase that
plays an important role in long bone development. The G380R mutation in FGFR3
transmembrane domain is known as the genetic cause for achondroplasia, the most
common form of human dwarfism. Despite many studies, there is no consensus about
the exact mechanism underlying the pathology. To gain further understanding into
the physical basis behind the disorder, here we measure the activation of
wild-type and mutant FGFR3 in mammalian cells using Western blots, and we
analyze the activation within the frame of a physical-chemical model describing
dimerization, ligand binding, and phosphorylation probabilities within the
dimers. The data analysis presented here suggests that the mutation does not
increase FGFR3 dimerization, as proposed previously. Instead, FGFR3 activity in
achondroplasia is increased due to increased probability for phosphorylation of
the unliganded mutant dimers. This finding has implications for the design of
targeted molecular treatments for achondroplasia. Achondrogenesis type II is an autosomal-domit disease leading to severe
micromelic dwarfism. Here, we report on the postmortem identification of a de
novo heterozygous mutation in the COL2A1 gene (c.1529G>A, p.Gly510Asp) in a
fetus who presented with generalized hydrops fetalis and severe micromelia
during prenatal sonographic examinations. Initially, a reciprocal translocation
t(4;17)(q31;p13) was detected in this fetus by chorionic villus sampling.
Subsequent chromosomal analysis of maternal and paternal blood showed that the
patient's mother was carrier of the same reciprocal translocation. SNP array
analysis of the fetus did not provide evidence for chromosomal imbalances or
CNVs that could be associated with the fetal phenotype. The coexistence of a
cytogenetic (reciprocal translocation) and a molecular genetic (COL2A1 mutation)
abnormality in the fetus carries important implications for genetic counseling. |
What is the indication for Mirabegron? | Mirabegron, the first 尾3-adrenoceptor agonist in clinical practice, is approved for treatment of overactive bladder (OAB) syndrome symptoms. | Mirabegron (YM-178), currently in development by Astellas Pharma Inc, is an
orally active β₃-adrenoceptor (AR) agonist for the potential symptomatic
treatment of overactive bladder (OAB). Mirabegron demonstrates omolar EC50
values against the human β₃-AR in biochemical assays with potent selectivity
over the β₁- and β₂-ARs. Originally developed as a treatment for diabetes, the
development of mirabegron was later refocused to OAB. Cystometric experiments in
rats reported a reduction in resting intravesical pressure and contraction
frequency in anesthetized rats, without any effect on the amplitude of
micturition contraction. Mirabegron also reduced non-micturition bladder
contractions in an awake rat model of bladder outlet obstruction. Top-line
results from clinical trials to date indicate that mirabegron has been well
tolerated with significant efficacy in reducing the number of incontinence
episodes and mean micturition frequency in patients. Evidence of cytochrome P450
(CYP)2D6 inhibition in clinical trials highlighted a concern for pharmacokinetic
interaction with other drugs that are CYP2D6 substrates, as confirmed by a rise
in the pharmacokinetic parameters of desipramine with concomitant administration
of mirabegron. Mirabegron exhibits a novel mode of action in targeting the β₃-AR
for bladder relaxation, and the studies and trials conducted to date suggest
mirabegron as a promising new treatment in the management of OAB symptoms, such
as increased urinary urgency and frequency, and urgency incontinence. BACKGROUND: Mirabegron is the first β3-adrenoceptor agonist that is clinically
effective for overactive bladder.
OBJECTIVE: The effects of mirabegron on primary bladder mechanosensitive
single-unit afferent activities (SAAs) and bladder microcontractions were
evaluated and compared with the effects of oxybutynin.
DESIGN, SETTING, AND PARTICIPANTS: Female Sprague-Dawley rats were anesthetized.
The SAAs generated from left L6 dorsal roots were identified by electrical
stimulation of the left pelvic nerve and bladder distension. Nerves with
conduction velocities (CVs) >2.5 m/s were designated as Aδ-fibers, and nerves
with CVs<2.5 m/s were designated as C-fibers.
OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Two measurements were performed
in separate animals. First, after measuring the baselines of SAA during constant
filling cystometry, the procedure was repeated with each intravenous
administration of mirabegron at three doses-0.1, 0.3, and 1.0mg/kg-cumulatively.
Second, the bladder was filled with saline until the intravesical pressure
reached 30 cm H(2)O and was kept under an isovolumetric condition; then the
recording was performed for 5 min with vehicle and mirabegron or oxybutynin
administrated intravenously.
RESULTS AND LIMITATIONS: A total of 74 single-unit afferent fibers were isolated
from 55 rats (Aδ-fibers: n=34; C-fibers: n=40). SAAs of both Aδ-fibers and
C-fibers in response to bladder filling significantly decreased after mirabegron
administration in a dose-dependent manner, which was more remarkable for
Aδ-fibers. During an isovolumetric condition of the bladder, the mean bladder
pressure and the number of microcontractions decreased after mirabegron
administration, whereas these parameters did not change with oxybutynin
administration. SAAs of Aδ-fibers were significantly decreased by mirabegron
administration at both 0.3 and 1mg/kg, whereas SAAs of C-fibers decreased only
at 1mg/kg. In contrast, oxybutynin (1mg/kg) did not alter either type of SAA.
CONCLUSIONS: The present study demonstrates that mirabegron can inhibit
mechanosensitive bladder afferent activity, especially of Aδ-fibers, which may
be related to suppression of bladder microcontractions. Researchers are constantly seeking ways to improve existing drugs, drug
mechanisms of activity, find new indications for old drugs or to develop new
drugs to treat urological diseases and conditions. In Canada, tadalafil in a 5
mg daily dosage (old drug), and a new drug, silodosin, have recently become
available to treat patients who have benign prostatic hyperplasia (BPH) with
lower urinary tract symptoms (LUTS). In clinical studies, silodosin has shown
promise as a treatment for ureteral stones, whereas it has shown conflicting
results as a potential treatment for prostatitis. Two new therapies have emerged
for treating overactive bladder (OAB): Mirabegron (not yet available in Canada)
and fesoterodine (newly introduced in the marketplace). New therapies--denosumab
(to prevent skeletal events) and abiraterone acetate and enzalutamide--were
recently approved to treat certain patients with advanced prostate cancer. With
the advent of new therapies to treat urological diseases, in many cases, primary
management of the patient is often shifted from the urologist to the family
physician, and sometimes moved from the oncologist to the urologist. OBJECTIVE: To review the place in therapy of mirabegron, a new oral
β3-adrenergic receptor agonist, for the treatment of overactive bladder (OAB).
DATA SOURCES: A literature search of MEDLINE and MEDLINE In-Process & Other
Non-Indexed Citations Databases (1996-April 2013) was conducted using the key
words mirabegron, receptor, adrenergic, beta-3; adrenergic beta-3 receptor;
beta-3 receptor, and overactive bladder; urinary bladder; overactive. All
published articles regarding mirabegron were included. References of selected
articles, data from poster presentations, and abstract publications were
additionally reviewed.
STUDY SELECTION AND DATA EXTRACTION: Available English-language data from
reviews, abstracts, presentations, and clinical trials of mirabegron in humans
were reviewed; relevant clinical data were selected and included.
DATA SYNTHESIS: Mirabegron is the newest option for treatment of OAB with
symptoms of urge incontinence. As a β3-receptor agonist, it reduces bladder
muscle contractions. In two 12-week, randomized, double-blind,
placebo-controlled Phase 3 studies, mirabegron significantly reduced the number
of incontinence episodes per 24 hours from baseline (-1.47, -1.63, and -1.13; p
< 0.05; and -1.57, -1.46, and -1.17; p < 0.05; all values for mirabegron 50 mg,
100 mg, and placebo). Micturitions per 24 hours were also reduced from baseline
(-1.66, -1.75, and -1.05; p < 0.05; and -1.93, -1.77, and -1.34; p < 0.05; all
values for mirabegron 50 mg, 100 mg, and placebo). A 12-month trial found
mirabegron to have a safety and efficacy profile similar to that of tolterodine.
CONCLUSIONS: Treatment of OAB initially includes lifestyle and nonpharmacologic
intervention; for patients with persistent symptoms despite these treatments,
drug therapy represents a next-step approach for symptom control. Mirabegron
alleviates symptoms of OAB while having a mechanism of action that provides an
alternative for patients who are intolerant of or who have contraindications to
anticholinergic agents. The place in therapy of mirabegron relative to
anticholinergics in the treatment of urge incontinence has not yet been
established. AIMS: Mirabegron, the first β3 -adrenoceptor agonist to enter clinical practice,
has a different mechanism of action from antimuscarinic agents. This review
presents data on the efficacy, safety, and tolerability of mirabegron in studies
conducted to date.
METHODS: All clinical data on mirabegron that are currently in the public domain
are included, including some in-press manuscripts.
RESULTS: In Phase III clinical trials in patients with overactive bladder (OAB),
mirabegron at daily doses of 25, 50, and 100 mg demonstrated significant
efficacy in treating the symptoms of OAB, including micturition frequency,
urgency incontinence, and urgency. Significant improvements in micturition
frequency, urgency incontinence, and mean volume voided/micturition were seen as
early as the first assessment (week 4) for mirabegron 50 and 100 mg, and were
maintained throughout treatment. Responder analyses showed a significant
improvement with mirabegron 50 and 100 mg in terms of dry rates, ≥50% reduction
in mean number of incontinence episodes/24 hr, and the proportion of patients
with ≤8 micturitions/24 hr at final visit. The benefit of mirabegron 50 and
100 mg was also evident in patients ≥65 years of age, and in both
treatment-naïve patients and those who previously discontinued antimuscarinic
therapy. These data therefore demonstrate a clinically meaningful benefit with
mirabegron in the objective endpoints of OAB. Assessment of measures of
health-related quality of life and treatment satisfaction showed that patients
perceived treatment with mirabegron as meaningful. In OAB clinical trials of up
to 12 months mirabegron appeared to be well tolerated. The most common adverse
events (AEs) observed with mirabegron in clinical trials of up to 12 months were
hypertension, nasopharyngitis, and urinary tract infection. The incidence of dry
mouth was similar to placebo, and was between three and fivefold less than for
tolterodine extended release 4 mg. Since dry mouth is the most bothersome AE
associated with antimuscarinic drugs and often a reason for treatment
discontinuation, mirabegron may be a valuable treatment option for these
patients.
CONCLUSIONS: In Phase III clinical trials, mirabegron at daily doses of 25, 50,
and 100 mg demonstrated significant efficacy in treating symptoms of OAB and, at
doses of 50 and 100 mg, demonstrated significant improvements versus placebo on
key secondary endpoints, as early as the first assessment (week 4), and these
were maintained throughout treatment. In OAB clinical trials of up to 12 months,
mirabegron appeared to be well tolerated. PURPOSE: Long-term persistence with pharmacotherapy for overactive bladder (OAB)
requires a drug with an early onset of action and good efficacy and tolerability
profile. Although antimuscarinics improve OAB symptoms within 1-2 weeks of
initiating treatment, adherence after 3 months is relatively poor due to
bothersome side effects (e.g., dry mouth and constipation). Mirabegron, a
β3-adrenoceptor agonist, has demonstrated significant improvements in key
symptoms of OAB and good tolerability after 12 weeks in Phase III studies.
METHODS: This was a prespecified pooled analysis of three randomized,
double-blind, placebo-controlled, 12-week studies, and a Phase II study, to
evaluate efficacy and tolerability of mirabegron 25 and 50 mg versus placebo.
The main efficacy endpoints were change from baseline to week 1 (Phase II only),
week 4, and final visit in mean number of incontinence episodes/24 h,
micturitions/24 h, and mean volume voided/micturition (MVV).
RESULTS: A significant benefit for mirabegron 25 and 50 mg versus placebo was
evident at the first assessment point, 4 weeks after initiation of therapy, in
Phase III studies for incontinence, micturitions, and MVV. The earliest measured
benefit was after 1 week, in the Phase II study. Quality-of-life parameters also
significantly improved with mirabegron 25 and 50 mg as early as week 4.
Significant benefits continued throughout the studies. Mirabegron was well
tolerated.
CONCLUSIONS: The early onset of action and good overall efficacy and
tolerability balance that mirabegron offers may lead to high rates of
persistence with mirabegron in the long-term treatment of OAB. To critically analyse available phase II and III randomised control trials
(RCTs) reporting clinical data about the efficacy and tolerability of Mirabegron
(a β₃-adrenoceptor agonist) in the treatment of overactive bladder (OAB)
syndrome. A review of the literature was performed in September 2013 using the
MEDLINE database. A 'free text' protocol was used for the search strategy using
'overactive bladder' and 'Mirabegron' as keywords. Subsequently, the searches
were pooled and limited to phase II and III RCTs. Two phase II and five phase
III RCTs were selected and analysed. The available phase II studies showed the
efficacy and tolerability of different doses of Mirabegron compared with
placebo. Moreover, a dose-ranging study showed that 50 mg once daily should be
considered the most promising dose for clinical use. The 12-week phase III
studies confirmed the effectiveness of Mirabegron to significantly reduce the
mean number of incontinence episodes/24 h and the mean number of
micturitions/24 h compared with placebo. A post hoc analysis confirmed that
favourable results with Mirabegron were reported both in patients with OAB who
were antimuscarinic naïve and in those who had discontinued prior antimuscarinic
therapy. Moreover, a phase III trial showed the safety and tolerability of
12-month treatment of Mirabegron. Discontinuation due to adverse events was low
both using the 50 and 100 mg dose of Mirabegron. Mirabegron is the first of a
new class of drugs for the treatment of OAB able to influence non-voiding
activity and produce an increased storage capacity and inter-void interval.
Recently published phase II and III RCTs have shown that the
β₃-adrenoceptor-selective agonist, Mirabegron, is an effective and safe drug for
the symptomatic treatment of OAB syndrome. Mirabegron represents a valid medical
option both for patients with OAB who are antimuscarinic naïve, as well as in
those where antimuscarinics are ineffective or not tolerated. CONTEXT: Mirabegron, the first β3-adrenoceptor agonist in clinical practice, is
approved for treatment of overactive bladder (OAB) syndrome symptoms. Because
β3-adrenoceptors are expressed in cardiovascular (CV) tissues, there are
concerns that OAB treatment with β3-adrenoceptor agonists may affect the heart
and vasculature.
OBJECTIVE: To provide a summary of CV effects of β3-adrenoceptor agonists in
clinical studies.
EVIDENCE ACQUISITION: A systematic literature search from inception until
November 2014 was performed on studies in PubMed and Medline.
EVIDENCE SYNTHESIS: Twenty papers, published between 1994 and 2014, were
identified: mirabegron (16), solabegron (2), AK-677 (1), and BRL35135 (1). More
detailed CV data from mirabegron studies were available in online regulatory
documents filed with the US Food and Drug Administration and the UK National
Institute for Health and Care Excellence.
CONCLUSIONS: The CV safety of mirabegron appears to be acceptable at therapeutic
doses and comparable with that of antimuscarinic agents, currently first-line
therapy for OAB.
PATIENT SUMMARY: In this review we looked at the cardiovascular (CV) effects of
β3-adrenoceptor agonists used for the treatment of overactive bladder (OAB). The
CV safety of mirabegron (the only clinically approved β3-adrenoceptor agonist)
appears to be acceptable at therapeutic doses and comparable with that of
antimuscarinic agents, the current first-line therapy for OAB. LINKED ARTICLE: This article is commented on by Michel, M. C., pp. 429-430 of
this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.13379.
BACKGROUND AND PURPOSE: Mirabegron is the first β3 -adrenoceptor agonist
approved for treatment of overactive bladder syndrome. This study aimed to
investigate the effects of β3 -adrenoceptor agonist mirabegron in mouse urethra.
The possibility that mirabegron also exerts α1 -adrenoceptor antagonism was also
tested in rat smooth muscle preparations presenting α1A - (vas deferens and
prostate), α1D - (aorta) and α1B -adrenoceptors (spleen).
EXPERIMENTAL APPROACH: Functional assays were carried out in mouse and rat
isolated tissues. Competition assays for the specific binding of [(3) H]prazosin
to membrane preparations of HEK-293 cells expressing each of the human α1
-adrenoceptors, as well as β-adrenoceptor mRNA expression and cyclic AMP
measurements in mouse urethra, were performed.
KEY RESULTS: Mirabegron produced concentration-dependent urethral relaxations
that were shifted to the right by the selective β3 -adrenoceptor antagonist
L-748,337 but unaffected by β1 - and β2 -adrenoceptor antagonists (atenolol and
ICI-118,551 respectively). Mirabegron-induced relaxations were enhanced by the
PDE4 inhibitor rolipram, and the agonist stimulated cAMP synthesis. Mirabegron
also produced rightward shifts in urethral contractions induced by the α1
-adrenoceptor agonist phenylephrine. Schild regression analysis revealed that
mirabegron behaves as a competitive antagonist of α1 -adrenoceptors in urethra,
vas deferens and prostate (α1A -adrenoceptor, pA2 ≅ 5.6) and aorta (α1D
-adrenoceptor, pA2 ≅ 5.4) but not in spleen (α1B -adrenoceptor). The affinities
estimated for mirabegron in functional assays were consistent with those
estimated in radioligand binding with human recombit α1A - and α1D
-adrenoceptors (pKi ≅ 6.0).
CONCLUSION AND IMPLICATIONS: The effects of mirabegron in urethral smooth muscle
are the result of β3 -adrenoceptor agonism together with α1A and α1D
-adrenoceptor antagonism. Antimuscarinic medications have long been the mainstay of drug treatment for
overactive bladder. This article describes mirabegron, one of a new class of
agents that relaxes the detrusor muscle directly via a beta3 adrenoceptor
agonist. Mirabegron's efficacy on frequency, urgency, and urge incontinence was
tested in several trials before its wide clinical introduction. However, caution
is still needed as data are lacking on the drug's efficacy and safety in frail
older adults and for long-term therapy. OBJECTIVES: To evaluate the efficacy and safety of the β3 -adrenoceptor agonist,
mirabegron, compared with placebo in Japanese patients with overactive bladder
(OAB).
METHODS: Patients with OAB symptoms for ≥24 weeks, ≥8 micturitions/24 h on
average, and ≥1 episode of urgency and/or urgency incontinence/24 h were
randomized to mirabegron (25, 50 or 100 mg) or placebo for 12 weeks. The primary
endpoint was change from baseline to end of study in the mean number of
micturitions/24 h. Secondary endpoints included micturition variables related to
urgency, incontinence, volume voided, and quality of life based on the King's
Health Questionnaire (KHQ). Safety was evaluated based on adverse events (AEs),
laboratory findings, vital signs, electrocardiogram, and post-void residual
volume.
RESULTS: In total, 842 patients were randomized to placebo (n = 214), mirabegron
25 mg (n = 211), 50 mg (n = 208), or 100 mg (n = 209). The primary endpoint was
significantly improved in each mirabegron group compared with placebo
(P < 0.001; Williams' multiple comparison test). The maximal efficacy in the
primary endpoint was observed at the 50 mg dose. Significant improvements were
also observed in incontinence, urgency incontinence, mean volume voided, and 3
of the 9 domains from the KHQ (incontinence impact, physical limitations, and
severity measures) at each mirabegron dose. Urgency episodes decreased, and mean
volume voided increased, dose-dependently. The incidence of AEs in each
mirabegron dose was comparable with placebo.
CONCLUSIONS: Mirabegron demonstrated significant improvements in OAB symptoms
compared with placebo and was well tolerated. Mirabegron is the first drug in a new class of oral therapy for overactive
bladder (OAB). It is a beta-3 adrenergic agonist, a class of drugs for the first
time used for the treatment of urination disorders. Recently, following many
years of rigorous multicenter randomized trials mirabegron has been approved for
use in Europe and North America. The clinical indication for mirabegron is
overactive bladder with symptoms of urge urinary incontinence, urgency, and
urinary frequency and other storage symptoms in both men and women. Mirabegron
is used in primary patients, or in patients who previously were unsuccessfully
treated with anticholinergics. The drug has a good safety profile and causes no
side effects typical of anticholinergics. CONTEXT: OnabotulinumtoxinA and mirabegron have recently gained marketing
authorisation to treat symptoms of overactive bladder (OAB).
OBJECTIVE: To evaluate the relative efficacy of mirabegron and
onabotulinumtoxinA in patients with idiopathic OAB.
DESIGN: Network meta-analysis.
DATA SOURCES: A search of 9 electronic databases, review documents, guidelines
and websites.
METHODS: Randomised trials comparing any licensed dose of onabotulinumtoxinA or
mirabegron with each other, anticholinergic drugs or placebo were eligible (19
randomised trials were identified). 1 reviewer extracted data from the studies
and a second reviewer checked the data. Candidate trials were assessed for
similarity and networks were developed for each outcome. Bayesian network
meta-analysis was conducted using both fixed-effects and random-effects models.
When there were differences in mean baseline values between mirabegron and
onabotulinumtoxinA trials they were adjusted for using network meta-regression
(NMR).
RESULTS: No studies directly comparing onabotulinumtoxinA to mirabegron were
identified. A network was created for each of the 7 outcomes, with 3-9 studies
included in each individual network. The trials included in the networks were
broadly similar. Patients in the onabotulinumtoxinA trials had more urinary
incontinence and urgency episodes at baseline than patients in the mirabegron
trials and these differences were adjusted for using NMR. Both
onabotulinumtoxinA and mirabegron were more efficacious than placebo at reducing
the frequency of urinary incontinence, urgency, urination and nocturia.
OnabotulinumtoxinA was more efficacious than mirabegron (50 and 25 mg) in
completely resolving daily episodes of urinary incontinence and urgency and in
reducing the frequency of urinary incontinence, urgency and urination. NMR
supported the results of the network meta-analysis.
CONCLUSIONS: In the absence of head-to-head trials comparing onabotulinumtoxinA
to mirabegron, this indirect comparison indicates that onabotulinumtoxinA may be
superior to mirabegron in improving symptoms of urinary incontinence, urgency
and urinary frequency in patients with idiopathic OAB. |
What is the cause of Tardive dyskinesia? | Tardive dyskinesia (TD) is a movement disorder characterized by abnormal involuntary facial movements induced by chronic therapy with classical antipsychotic medications. | Tardive dyskinesia (TD) is a movement disorder characterized by abnormal
involuntary facial movements induced by chronic therapy with classical
antipsychotic medications. Currently, there is no satisfactory pharmacotherapy
for TD, which represents a major limitation to therapy with classical
antipsychotics. In order to develop or optimize therapies for TD, and to develop
new APDs with lower indices of motor side effects, the pathology underlying TD
must first be understood. The use of animal models has been used to further this
objective. Here, we review different preparations that have been used to model
TD and discuss the contribution of neuroimaging studies conducted in these
models. Studies in animal models have lead to several hypotheses of TD
pathology, although none has yet emerged as the ultimate underlying cause of
this syndrome. We discuss alterations in functional indices, neuron and synapse
morphology and changes in specific neurotransmitter systems that have been
described in animal models of TD, and outline how these findings have
contributed to our understanding of antipsychotic-induced dyskinesias. We
conclude that several non-mutually exclusive theories of TD are supported by
animal studies, including increases in oxidative stress leading to structural
and functional changes in specific neurotransmitter systems. Elucidating the
mechanisms underlying TD neuropathology partly through the use of animal models
will lead to the development of APDs with superior side effect profiles or more
effective therapies for TD. Tardive dyskinesia (TD) is a serious, often disabling, movement disorder that is
caused by medications that block dopamine receptors (i.e., neuroleptics,
anti-emetics). There is currently no standard treatment approach for physicians
confronted with such patients. This may be the result of notions that TD is
disappearing because of the switch to second-generation antipsychotic agents and
that it is largely reversible. In this article we demonstrate that
second-generation antipsychotics do, indeed, cause TD and, in fact, the
frequency is likely higher than expected because of growing off-label uses and a
tripling of prescriptions written in the last 10 years. In addition, studies
demonstrate that TD actually remits in only a minority of patients when these
drugs are withdrawn. Furthermore, neuroleptic agents are often utilized to treat
TD, despite prolonged exposure being a risk factor for irreversibility. The
outcome of these trends is a growing population afflicted with TD. We review
non-neuroleptic agents that have shown positive results in small, early-phase,
blinded trials, including tetrabenazine, amantadine, levetiracetam, piracetam,
clonazepam, propranolol, vitamin B6, and Ginkgo biloba. Other options, such as
botulinum toxin and deep brain stimulation, will also be discussed, and a
suggested treatment algorithm is provided. While these agents are reasonable
treatment options at this time there is a need, with a concerted effort between
neurology and psychiatry, for full-scale drug development, including
multicenter, randomized, blinded trials to confirm the effectiveness of the
agents that were positive in phase 2 trials and the development of newer ones. |
Are alterations in ultraconserved elements associated with colorectal adenocarcinoma? | yes | We investigated whether single nucleotide polymorphisms within ultraconserved
elements (UCEs) are associated with susceptibility to overall colorectal cancer
(CRC) and susceptibility to tumor site-specific CRC. The study included 787 CRC
patients and 551 healthy controls. The study comprised of a training set (520
cases and 341 controls) and a replication set (267 cases and 210 controls). We
observed associations in rs7849 and rs1399685 with CRC risk. For example, a
dose-dependent trend (per-allele odds ratio (OR), 0.78; 95% confidence interval
(CI), 0.63-1.00; P for trend = 0.05) associated with the variant allele of
rs7849 in the training set. The significant trend toward a decrease in CRC risk
was confirmed in the replication set (per-allele OR, 0.72; 95% CI, 0.52-0.99; P
for trend = 0.044). When stratified by tumor location, for left-sided CRC (LCRC)
risk, significant association was observed for the variant-containing genotypes
of rs1399685 (OR, 1.77; 95% CI, 1.02-3.06) and the risk was replicated in the
replication population (OR, 2.04; 95% CI, 1.02-4.07). The variant genotypes of
rs9784100 and rs7849 conferred decreased risk but the associations were not
replicated. Three right-sided CRC (RCRC) susceptibility loci were identified in
rs6124509, rs4243289 and rs12218935 but none of the loci was replicated. Joint
effects and potential higher order gene-gene interactions among significant
variants further categorized patients into different risk groups. Our results
strongly suggest that several genetic variants in the UCEs may contribute to CRC
susceptibility, individually and jointly, and that different genetic etiology
may be involved in RCRC and LCRC. OBJECTIVES: The development of colorectal cancer (CRC) is characterized by
multiple genetic alterations. Transcribed ultraconserved regions (T-UCRs) are a
subset of 481 sequences longer than 200 bp, which are absolutely conserved
between orthologous regions of human, rat and mouse genomes, and are actively
transcribed. It has recently been proven in cancer systems that differentially
expressed T-UCRs could alter the functional characteristics of maligt cells.
Genome-wide profiling revealed that T-UCRs have distinct signatures in human
leukemia and carcinoma.
METHODS: In our study, we examined the expression levels of uc.43, uc.73,
uc.134, uc.230, uc.339, uc.388 and uc.399 in 54 samples of primary colorectal
carcinomas and 15 samples of non-tumoral adjacent tissues by real-time PCR.
T-UCR expression levels were also correlated with commonly used
clinicopathological features of CRC.
RESULTS: Expression levels of uc.73 (p = 0.0139) and uc.388 (p = 0.0325) were
significantly decreased in CRC tissue, and uc.73 indicated a positive
correlation with overall survival (p = 0.0315). The lower expression of uc.388
was associated with the distal location of CRC (p = 0.0183), but no correlation
of any evaluated T-UCR with clinical stage, grade and tumor diameter was
observed.
CONCLUSION: Our preliminary results suggest that uc.73 and uc.388 could be
potential diagnostic and prognostic biomarkers in CRC patients. |
What is PANTHER-PSEP? | PANTHER-PSEP is a new software tool for predicting non-synonymous genetic variants that may play a causal role in human disease. Several previous variant pathogenicity prediction methods have been proposed that quantify evolutionary conservation among homologous proteins from different organisms. PANTHER-PSEP employs a related but distinct metric based on 'evolutionary preservation': homologous proteins are used to reconstruct the likely sequences of ancestral proteins at nodes in a phylogenetic tree, and the history of each amino acid can be traced back in time from its current state to estimate how long that state has been preserved in its ancestors. | PANTHER-PSEP is a new software tool for predicting non-synonymous genetic
variants that may play a causal role in human disease. Several previous variant
pathogenicity prediction methods have been proposed that quantify evolutionary
conservation among homologous proteins from different organisms. PANTHER-PSEP
employs a related but distinct metric based on 'evolutionary preservation':
homologous proteins are used to reconstruct the likely sequences of ancestral
proteins at nodes in a phylogenetic tree, and the history of each amino acid can
be traced back in time from its current state to estimate how long that state
has been preserved in its ancestors. Here, we describe the PSEP tool, and assess
its performance on standard benchmarks for distinguishing disease-associated
from neutral variation in humans. On these benchmarks, PSEP outperforms not only
previous tools that utilize evolutionary conservation, but also several highly
used tools that include multiple other sources of information as well. For
predicting pathogenic human variants, the trace back of course starts with a
human 'reference' protein sequence, but the PSEP tool can also be applied to
predicting deleterious or pathogenic variants in reference proteins from any of
the ∼100 other species in the PANTHER database.
AVAILABILITY AND IMPLEMENTATION: PANTHER-PSEP is freely available on the web at
http://pantherdb.org/tools/csnpScoreForm.jsp Users can also download the
command-line based tool at ftp://ftp.pantherdb.org/cSNP_analysis/PSEP/ CONTACT:
[email protected]
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics
online. |
What is MPE-seq? | MPE-seq (methidiumpropyl-EDTA sequencing) is a new method for the genome-wide characterization of chromatin that involves the digestion of nuclei with MPE-Fe(II) followed by massively parallel sequencing. Like micrococcal nuclease (MNase), MPE-Fe(II) preferentially cleaves the linker DNA between nucleosomes. However, there are differences in the cleavage of nuclear chromatin by MPE-Fe(II) relative to MNase. MPE-seq provides a unique and straightforward means for the genome-wide analysis of chromatin structure with minimal DNA sequence bias. In particular, the combined use of MPE-seq and MNase-seq enables the identification of noncanonical chromatin structures that are likely to be important for the regulation of gene expression. | |
Describe the mechanism of action of Bezlotoxumab? | Bezlotoxumab (Zinplava™) is a human monoclonal antibody against Clostridium difficile toxin B (TcdB). It is used for prevention of recurrent C. difficile infections. | The symptoms of Clostridium difficile infections are caused by two exotoxins,
TcdA and TcdB, which target host colonocytes by binding to unknown cell surface
receptors, at least in part via their combined repetitive oligopeptide (CROP)
domains. A combination of the anti-TcdA antibody actoxumab and the anti-TcdB
antibody bezlotoxumab is currently under development for the prevention of
recurrent C. difficile infections. We demonstrate here through various
biophysical approaches that bezlotoxumab binds to specific regions within the
N-terminal half of the TcdB CROP domain. Based on this information, we solved
the x-ray structure of the N-terminal half of the TcdB CROP domain bound to Fab
fragments of bezlotoxumab. The structure reveals that the TcdB CROP domain
adopts a β-solenoid fold consisting of long and short repeats and that
bezlotoxumab binds to two homologous sites within the CROP domain, partially
occluding two of the four putative carbohydrate binding pockets located in TcdB.
We also show that bezlotoxumab neutralizes TcdB by blocking binding of TcdB to
mammalian cells. Overall, our data are consistent with a model wherein a single
molecule of bezlotoxumab neutralizes TcdB by binding via its two Fab regions to
two epitopes within the N-terminal half of the TcdB CROP domain, partially
blocking the carbohydrate binding pockets of the toxin and preventing toxin
binding to host cells. The exotoxins TcdA and TcdB are the major virulence factors of Clostridium
difficile. Circulating neutralizing antitoxin antibodies are protective in C.
difficile infection (CDI), as demonstrated, in part, by the protective effects
of actoxumab and bezlotoxumab, which bind to and neutralize TcdA and TcdB,
respectively. The question of how systemic IgG antibodies neutralize toxins in
the gut lumen remains unresolved, although it has been suggested that the Fc
receptor FcRn may be involved in active antibody transport across the gut
epithelium. In this study, we demonstrated that genetic ablation of FcRn and
excess irrelevant human IgG have no impact on actoxumab-bezlotoxumab-mediated
protection in murine and hamster models of CDI, suggesting that Fc-dependent
transport of antibodies across the gut wall is not required for efficacy. Tissue
distribution studies in hamsters suggest, rather, that the transport of
antibodies depends on toxin-induced damage to the gut lining. In an in vitro
two-dimensional culture system that mimics the architecture of the intestinal
mucosal epithelium, toxins on the apical side of epithelial cell monolayers are
neutralized by basolateral antibodies, and antibody transport across the cell
layer is dramatically increased upon addition of toxin to the apical side.
Similar data were obtained with F(ab')2 fragments, which lack an Fc domain,
consistent with FcRn-independent paracellular, rather than transcellular,
transport of antibodies. Kinetic studies show that initial damage caused by
apical toxin is required for efficient neutralization by basolateral antibodies.
These data may represent a general mechanism of humoral response-mediated
protection against enteric pathogens. Clostridium difficile infections (CDIs) are the leading cause of
hospital-acquired infectious diarrhea and primarily involve two exotoxins, TcdA
and TcdB. Actoxumab and bezlotoxumab are human monoclonal antibodies that
neutralize the cytotoxic/cytopathic effects of TcdA and TcdB, respectively. In a
phase II clinical study, the actoxumab-bezlotoxumab combination reduced the rate
of CDI recurrence in patients who were also treated with standard-of-care
antibiotics. However, it is not known whether the antibody combination will be
effective against a broad range of C. difficile strains. As a first step toward
addressing this, we tested the ability of actoxumab and bezlotoxumab to
neutralize the activities of toxins from a number of clinically relevant and
geographically diverse strains of C. difficile. Neutralization potencies, as
measured in a cell growth/survival assay with purified toxins from various C.
difficile strains, correlated well with antibody/toxin binding affinities.
Actoxumab and bezlotoxumab neutralized toxins from culture supernatants of all
clinical isolates tested, including multiple isolates of the BI/NAP1/027 and
BK/NAP7/078 strains, at antibody concentrations well below plasma levels
observed in humans. We compared the bezlotoxumab epitopes in the TcdB receptor
binding domain across known TcdB sequences and found that key substitutions
within the bezlotoxumab epitopes correlated with the relative differences in
potencies of bezlotoxumab against TcdB of some strains, including ribotypes 027
and 078. Combined with in vitro neutralization data, epitope modeling will
enhance our ability to predict the coverage of new and emerging strains by
actoxumab-bezlotoxumab in the clinic. Clostridium difficile infection (CDI) represents the most prevalent cause of
antibiotic-associated gastrointestinal infections in health care facilities in
the developed world. Disease symptoms are caused by the two homologous
exotoxins, TcdA and TcdB. Standard therapy for CDI involves administration of
antibiotics that are associated with a high rate of disease recurrence,
highlighting the need for novel treatment paradigms that target the toxins
rather than the organism itself. A combination of human monoclonal antibodies,
actoxumab and bezlotoxumab, directed against TcdA and TcdB, respectively, has
been shown to decrease the rate of recurrence in patients treated with
standard-of-care antibiotics. However, the exact mechanism of antibody-mediated
protection is poorly understood. In this study, we show that the antitoxin
antibodies are protective in multiple murine models of CDI, including systemic
and local (gut) toxin challenge models, as well as primary and recurrent models
of infection in mice. Systemically administered actoxumab-bezlotoxumab prevents
both the damage to the gut wall and the inflammatory response, which are
associated with C. difficile in these models, including in mice challenged with
a strain of the hypervirulent ribotype 027. Furthermore, mutant antibodies
(N297Q) that do not bind to Fcγ receptors provide a level of protection similar
to that of wild-type antibodies, demonstrating that the mechanism of protection
is through direct neutralization of the toxins and does not involve host
effector functions. These data provide a mechanistic basis for the prevention of
recurrent disease observed in CDI patients in clinical trials. Clostridium difficile causes infections of the colon in susceptible patients.
Specifically, gut dysbiosis induced by treatment with broad-spectrum antibiotics
facilitates germination of ingested C. difficile spores, expansion of vegetative
cells, and production of symptom-causing toxins TcdA and TcdB. The current
standard of care for C. difficile infections (CDI) consists of administration of
antibiotics such as vancomycin that target the bacterium but also perpetuate gut
dysbiosis, often leading to disease recurrence. The monoclonal antitoxin
antibodies actoxumab (anti-TcdA) and bezlotoxumab (anti-TcdB) are currently in
development for the prevention of recurrent CDI. In this study, the effects of
vancomycin or actoxumab/bezlotoxumab treatment on progression and resolution of
CDI were assessed in mice and hamsters. Rodent models of CDI are characterized
by an early severe phase of symptomatic disease, associated with high rates of
morbidity and mortality; high intestinal C. difficile burden; and a disrupted
intestinal microbiota. This is followed in surviving animals by gradual recovery
of the gut microbiota, associated with clearance of C. difficile and resolution
of disease symptoms over time. Treatment with vancomycin prevents disease
initially by inhibiting outgrowth of C. difficile but also delays microbiota
recovery, leading to disease relapse following discontinuation of therapy. In
contrast, actoxumab/bezlotoxumab treatment does not impact the C. difficile
burden but rather prevents the appearance of toxin-dependent symptoms during the
early severe phase of disease, effectively preventing disease until the
microbiota (the body's natural defense against C. difficile) has fully
recovered. These data provide insight into the mechanism of recurrence following
vancomycin administration and into the mechanism of recurrence prevention
observed clinically with actoxumab/bezlotoxumab. |
Is apremilast effective for psoriasis? | Yes, apremilast is effective for treatment of psoriasis. | INTRODUCTION: Psoriasis is a common skin disorder characterized by chronic
inflammatory lesions that are frequently vexing for patients and difficult for
physicians to treat. Although multiple therapeutic options are available, all
have limitations. Topical preparations have issues with patient adherence, as
compared to oral routes of administration. Currently available oral medications,
such as methotrexate, possess unfavorable toxicity profiles that limit use.
There is a large unmet need for an effective, safe oral treatment for psoriasis.
Apremilast is an oral medication that inhibits the activity of multiple
inflammatory markers involved in the pathogenesis of psoriasis.
AREAS COVERED: The present review article presents the pharmacokinetic
properties of apremilast, as well as available preliminary pre-clinical and
clinical trial data, and gives an overview of its safety and efficacy.
EXPERT OPINION: Apremilast has been well tolerated in phase I and II clinical
trials. It has favorable safety and toxicity profiles at doses that are also
effective for the treatment of plaque psoriasis. Phase III clinical trials are
currently underway and will better elucidate appropriate dosing of apremilast
and further illuminate its side effect profile. In future studies, a comparison
of apremilast to other psoriasis medications administered through different
routes would be beneficial, to document whether patient adherence is better with
an oral medication. Depending on the price of the agent, efficacy and perhaps
most importantly its safety profile, apremilast may fill a key need as a safe,
first-line oral treatment for patients with psoriasis. BACKGROUND: Apremilast, a specific inhibitor of phosphodiesterase 4, modulates
pro-inflammatory and anti-inflammatory cytokine production.
OBJECTIVES: Apremilast's effect on patient-reported outcomes (PROs) in patients
with moderate to severe psoriasis was evaluated in a phase IIb randomized,
controlled trial (NCT00773734).
METHODS: In this 16-week, placebo-controlled study, 352 patients with moderate
to severe plaque psoriasis received placebo or apremilast (10, 20, or 30 mg
BID). PROs included Dermatology Life Quality Index (DLQI), pruritus visual
analog scale (VAS), and Short-Form Health Survey (SF-36) to assess
health-related quality of life (HRQOL). Changes from baseline and patients
reporting improvements ≥minimum clinically important differences (MCID) were
analyzed. Correlations between changes across various PRO instruments were
explored.
RESULTS: Baseline DLQI (>10 points) and SF-36 MCS and domain scores indicated
impairments in HRQOL. At 16 weeks, greater improvements from baseline in DLQI
scores were reported with apremilast 20 (-5.9) and 30 mg BID (-4.4) compared
with placebo (1.9; P≤0.005 for both), and a greater proportion of patients
reported improvements ≥MCID (20 mg BID, 49.4%, 30 mg BID, 44.3%) versus placebo
(25.0%; P<0.04). Greater improvements from baseline in pruritus VAS scores were
reported with apremilast 20 (-35.5%) and 30 mg BID (-43.7%) versus placebo
(-6.1%; P≤0.005). Significant and clinically meaningful improvements in SF-36
mental component summary scores (P≤0.008) and Bodily Pain, Mental Health, and
Role-Emotional domains were reported with all apremilast doses (P<0.05), and
Social Functioning with 20 and 30 mg BID (P<0.05) and Physical Functioning with
20 mg BID (P<0.03). Correlations between SF-36 scores and DLQI were moderate
(r>0.30 and ≤0.60) and low between SF-36 and pruritus VAS (r≤0.30), indicating
they measure different aspects of the disease.
CONCLUSIONS: Apremilast treatment resulted in improved HRQOL, including DLQI and
pruritus VAS over 16 weeks of treatment, in patients with moderate to severe
psoriasis. OBJECTIVES: Apremilast, an oral phosphodiesterase 4 inhibitor, regulates
inflammatory mediators. Psoriatic Arthritis Long-term Assessment of Clinical
Efficacy 1 (PALACE 1) compared apremilast with placebo in patients with active
psoriatic arthritis despite prior traditional disease-modifying antirheumatic
drug (DMARD) and/or biologic therapy.
METHODS: In the 24-week, placebo-controlled phase of PALACE 1, patients (N=504)
were randomised (1:1:1) to placebo, apremilast 20 mg twice a day (BID) or
apremilast 30 mg BID. At week 16, patients without ≥20% reduction in swollen and
tender joint counts were required to be re-randomised equally to either
apremilast dose if initially randomised to placebo or remained on their initial
apremilast dose. Patients on background concurrent DMARDs continued stable doses
(methotrexate, leflunomide and/or sulfasalazine). Primary outcome was the
proportion of patients achieving 20% improvement in modified American College of
Rheumatology response criteria (ACR20) at week 16.
RESULTS: At week 16, significantly more apremilast 20 mg BID (31%) and 30 mg BID
(40%) patients achieved ACR20 versus placebo (19%) (p<0.001). Significant
improvements in key secondary measures (physical function, psoriasis) were
evident with both apremilast doses versus placebo. Across outcome measures, the
30-mg group generally had higher and more consistent response rates, although
statistical comparison was not conducted. The most common adverse events were
gastrointestinal and generally occurred early, were self-limiting and
infrequently led to discontinuation. No imbalance in major adverse cardiac
events, serious or opportunistic infections, maligcies or laboratory
abnormalities was observed.
CONCLUSIONS: Apremilast was effective in the treatment of psoriatic arthritis,
improving signs and symptoms and physical function. Apremilast demonstrated an
acceptable safety profile and was generally well tolerated.
CLINICAL TRIAL REGISTRATION NUMBER: NCT01172938. BACKGROUND: Apremilast works intracellularly to regulate inflammatory mediators.
OBJECTIVE: ESTEEM 1 evaluated efficacy/safety of apremilast at 30 mg twice a day
for moderate to severe plaque psoriasis.
METHODS: This phase III, multicenter, double-blind, placebo-controlled study
randomized adults (2:1) to apremilast or placebo. At week 16, the placebo group
switched to apremilast through week 32, followed by a randomized treatment
withdrawal phase to week 52. Binary end points were analyzed using χ(2) test;
continuous end points used analysis of covariance.
RESULTS: In all, 844 patients were randomized (n = 282, placebo; n = 562,
apremilast). At week 16, significantly more patients taking apremilast achieved
75% or greater reduction from baseline Psoriasis Area and Severity Index score
(PASI-75) (33.1%) versus placebo (5.3%, P < .0001; primary end point). Most
(61.0%) patients rerandomized to apremilast at week 32 achieved PASI-75 at week
52 versus 11.7% rerandomized to placebo. Of patients rerandomized to apremilast
at week 32, mean percentage change from baseline PASI score was -88% to -81%
(weeks 32-52). During the placebo-controlled period, 55.7% and 69.3% of patients
randomized to placebo and apremilast, respectively, had 1 or more adverse
events. Most adverse events were mild/moderate in severity. No new significant
adverse events emerged with continued apremilast exposure versus the
placebo-controlled period.
LIMITATIONS: Data were limited to 52 weeks and may not generalize to nonplaque
psoriasis.
CONCLUSIONS: Apremilast was effective in moderate to severe plaque psoriasis. Apremilast (Otezla(®)) is an oral phosphodiesterase 4 inhibitor indicated for
the twice-daily treatment of adults with psoriasis and psoriatic arthritis
(PsA). Its use in these patient populations has been assessed in two phase III
clinical trial programmes (ESTEEM and PALACE). At 16 weeks in the two ESTEEM
trials, apremilast reduced the severity and extent of moderate to severe plaque
psoriasis, including nail, scalp and palmoplantar manifestations, versus placebo
in adults, with these benefits generally being sustained over 52 weeks of
treatment. Similarly, in three PALACE trials (PALACE 1-3), apremilast improved
the signs and symptoms of PsA relative to placebo at 16 weeks in adults with
active disease despite treatment with conventional synthetic and/or biologic
disease-modifying anti-rheumatic drugs. These PsA benefits were generally
sustained for up to 104 weeks of treatment; skin involvement, enthesitis and
dactylitis also improved with the drug. Apremilast was generally well tolerated,
with the most common adverse events being diarrhoea and nausea in the first year
of treatment (usually occurring in the first 2 weeks after the first dose and
resolving within 4 weeks) and nasopharyngitis and upper respiratory tract
infection with continued treatment. Although further longer-term and comparative
efficacy and tolerability data would be beneficial, the current clinical data
indicate that apremilast is an effective and well tolerated option for the
management of psoriasis and PsA in adults. INTRODUCTION: Psoriasis is a chronic inflammatory skin disease characterized by
dysregulation of the immune system and release of pro-inflammatory mediators.
Drugs available for psoriasis show some limits as tolerability and route of
administration. Apremilast , Otezla®, is an oral small molecule recently
approved for the treatment of patients with moderate-to-severe plaque psoriasis.
Compared to biologics that target a single cytokine, apremilast, degrading
phosphodiesterase 4 (PDE4), interferes with cyclic anti-microbial peptides,
which is involved in the transduction of intracellular signals, controlling the
balance of pro-inflammatory and anti-inflammatory signals.
AREAS COVERED: This review reported the latest data available from Phase I, II
and III trials on apremilast for the treatment of plaque psoriasis. A focus on
the clinical management of apremilast, safety and clinical efficacy based on two
pivotal clinical trials (ESTEEM 1 and ESTEEM 2) currently ongoing was described.
A systematic search was conducted using the PubMed Medline database for primary
articles.
EXPERT OPINION: Apremilast treatment was demonstrated effective and well
tolerated in Phase II and III clinical trials. Several drug peculiarities, such
as the low frequency of adverse events and the oral route of administration,
make apremilast an innovative treatment for moderate-to-severe psoriasis. BACKGROUND: Increased knowledge of the molecular regulatory mechanisms that
contribute to the pathogenesis of psoriasis and other inflammatory diseases has
created new opportunities for the development of targeted drug therapy for
inflammatory conditions. Two new oral medications, apremilast and tofacitinib,
have been developed for their immunomodulatory properties, and their potential
efficacy in treating psoriasis is being evaluated.
METHODS: We reviewed phase III randomized, placebo-controlled clinical trial
results for apremilast and tofacitinib for efficacy and safety in psoriasis.
RESULTS: Psoriasis Area and Severity Index (PASI) 75 after 16 weeks for
apremilast was between 28.8% and 33.1%. PASI 75 was 39.5% after 12 weeks on
tofacitinib 5 mg, and 63.6% after 12 weeks on tofacitinib 10 mg. Common side
effects for both drugs included nasopharyngitis and upper respiratory tract
infections. Gastrointestinal disturbance was common for apremilast. Dyslipidemia
and infections were more common with tofacitinib than placebo.
CONCLUSION: Both new oral medications, apremilast and tofacitinib, appear to be
effective in treating psoriasis BACKGROUND: Apremilast, an oral phosphodiesterase 4 inhibitor, regulates immune
responses associated with psoriasis.
OBJECTIVES: ESTEEM 2 evaluated the efficacy and safety of apremilast 30 mg twice
daily for moderate-to-severe plaque psoriasis.
METHODS: This phase III, double-blind, placebo-controlled trial randomized
adults to apremilast or placebo (2 : 1). At week 16, placebo patients switched
to apremilast. At week 32, apremilast patients achieving ≥ 50% reduction in
Psoriasis Area and Severity Index (PASI 50) were rerandomized (1 : 1) to
continue apremilast or receive placebo. Upon loss of 50% of PASI improvement
obtained at week 32, patients rerandomized to placebo resumed apremilast.
RESULTS: The modified intention-to-treat population (full analysis set) included
137 placebo and 274 apremilast patients. At week 16, significantly more
apremilast patients achieved PASI 75 (28·8%), PASI 50 (55·5%) and static
Physician's Global Assessment score of 0 or 1 (20·4%) vs. placebo (5·8%, 19·7%,
4·4%, respectively; P < 0·001). Most patients rerandomized to apremilast at week
32 had a PASI 50 response at week 52 (80%). Patients treated with apremilast
showed significant improvements in quality of life (as assessed by the
Dermatology Life Quality Index) and pruritus at week 16 compared with placebo
(P < 0·001). The exposure-adjusted incidence of adverse events did not increase
with continued apremilast treatment for up to 52 weeks. The most common adverse
events were nausea, diarrhoea, nasopharyngitis and upper respiratory tract
infection.
CONCLUSIONS: Apremilast was effective in the treatment of moderate-to-severe
plaque psoriasis over 52 weeks. BACKGROUND: In the phase III double-blind Efficacy and Safety Trial Evaluating
the Effects of Apremilast in Psoriasis (ESTEEM) 1 and 2, apremilast, an oral
phosphodiesterase 4 inhibitor, demonstrated efficacy in moderate to severe
psoriasis.
OBJECTIVE: We sought to evaluate efficacy of apremilast in nail/scalp psoriasis
in ESTEEM 1 and 2.
METHODS: A total of 1255 patients were randomized (2:1) to apremilast 30 mg
twice daily or placebo. At week 16, placebo patients switched to apremilast
through week 32, followed by a randomized withdrawal phase to week 52. A priori
efficacy analyses included patients with nail (target nail Nail Psoriasis
Severity Index score ≥1) and moderate to very severe scalp (Scalp Physician
Global Assessment score ≥3) psoriasis at baseline.
RESULTS: At baseline, 66.1% and 64.7% of patients had nail psoriasis; 66.7% and
65.5% had moderate to very severe scalp psoriasis in ESTEEM 1 and 2. At week 16,
apremilast produced greater improvements in Nail Psoriasis Severity Index score
versus placebo; mean percent change: -22.5% versus +6.5% (ESTEEM 1; P < .0001)
and -29.0% versus -7.1% (ESTEEM 2; P = .0052). At week 16, apremilast produced
greater NAPSI-50 response (50% reduction from baseline in target nail Nail
Psoriasis Severity Index score) versus placebo (both studies P < .0001) and
ScPGA response (Scalp Physician Global Assessment score 0 or 1) versus placebo
(both studies P < .0001). Improvements were generally maintained over 52 weeks
in patients with Psoriasis Area and Severity Index response at week 32.
LIMITATIONS: Baseline randomization was not stratified for nail/scalp psoriasis.
CONCLUSION: Apremilast reduces the severity of nail/scalp psoriasis. Author information:
(1)Sorbonne Universités, UPMC Univ Paris 06, Institut Pierre Louis
d'Epidémiologie et de Santé Publique, GRC-UPMC 08 (EEMOIS), Paris, France
Department of rheumatology, AP-HP, Pitié Salpêtrière Hospital, Paris, France.
(2)Division of Rheumatology, Department of Medicine 3, Medical University of
Vienna, Vienna, Austria Second Department of Medicine, Hietzing Hospital,
Vienna, Austria.
(3)Department of Rheumatology, Leiden University Medical Centre, Leiden, The
Netherlands.
(4)EULAR, representing People with Arthritis/Rheumatism in Europe (PARE),
London, UK.
(5)Research Laboratory and Clinical Division of Rheumatology, Department of
Internal Medicine, University of Genova, Viale Benedetto, Italy.
(6)Medicine Faculty, Paris Descartes University, Paris, France Rheumatology B
Department, APHP, Cochin Hospital, Paris, France.
(7)Leeds NIHR Musculoskeletal Biomedical Research Unit, LTHT, Leeds, UK Leeds
Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds,
UK.
(8)Department of Clinical Immunology & Rheumatology, Amsterdam Rheumatology
Center, Amsterdam, The Netherlands Atrium Medical Center, Heerlen, The
Netherlands.
(9)North Devon, UK.
(10)Division of Rheumatology, Department of Medicine 3, Medical University of
Vienna, Vienna, Austria.
(11)Rheumazentrum Ruhrgebiet, Herne and Ruhr-Universität Bochum, Herne, Germany.
(12)Department of Rheumatology and Clinical Immunology, Charité-University
Medicine Berlin, Germany.
(13)Arthritis Unit, Department of Rheumatology, Hospital Clínic and IDIBAPS,
Barcelona, Spain.
(14)Belgrade University School of Medicine, Belgrade, Serbia.
(15)Department of Rheumatology, St. Vincent's University Hospital and Conway
Institute, University College Dublin, Dublin, Ireland.
(16)Section of Rheumatology, Department of Clinical Sciences, Lund University,
Lund, Sweden Sweden and School of Business, Engineering and Science, Halmstad
University, Halmstad, Sweden.
(17)Section of Musculoskeletal Disease, Leeds Institute of Molecular Medicine,
University of Leeds, Leeds, UK.
(18)Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
(19)Laboratory of Tissue Homeostasis and Disease, Skeletal Biology and
Engineering Research Center, KU Leuven, Belgium Division of Rheumatology,
University Hospitals Leuven, Leuven, Belgium.
(20)Department of Dermatology, University Hospital Münster, Münster, Germany.
(21)A.DI.PSO. (Associazione per la Difesa degli Psoriasici)-PE.Pso.POF (Pan
European Psoriasis Patients' Organization Forum), Rome, Italy.
(22)Institute of Infection, Immunity and Inflammation, University of Glasgow,
Glasgow, UK.
(23)Rheumatology Department of Lucania, San Carlo Hospital of Potenza and
Madonna delle Grazie Hospital of Matera, Potenza, Italy.
(24)Institute and Clinic of Rheumatology Charles University Prague, Czech
Republic.
(25)Department of Internal Medicine 3, University of Erlangen-Nuremberg,
Erlangen, Germany.
(26)Department of Rheumatology, Campus Benjamin Franklin, Charité, Berlin,
Germany.
(27)Ghent University Hospital, Ghent, Belgium.
(28)Centre for Arthritis and Rheumatic Disease, Dublin Academic Medical Centre,
St. Vincent's University Hospital, Dublin, Ireland.
(29)Schoen Klinik Hamburg, Rheumatology and Clinical Immunology, Hamburg,
Germany.
(30)Department of Rheumatology and Clinical Immunology, German Rheumatism
Research Centre Berlin, Charité-University Medicine Berlin, Germany. OBJECTIVE: To update the evidence on the efficacy and safety of pharmacological
agents in psoriatic arthritis (PsA).
METHODS: Systematic literature review of randomised controlled trials comparing
pharmacological interventions in PsA: non-steroidal anti-inflammatory drugs,
glucocorticoid, synthetic disease modifying antirheumatic drugs (sDMARDs) either
conventional or targeted, biologicals (bDMARDs), placebo or any combination.
Main outcomes were American College of Rheumatology (ACR)20-50, Psoriasis Area
Severity Index 75, radiographic progression, and withdrawals due to adverse
events (AEs). Multiple studies of the same intervention were meta-analysed using
random effects.
RESULTS: In total, 25 papers and 12 abstracts were included. The efficacy of
tumour necrosis factor inhibitors (including the recently added golimumab and
certolizumab pegol) was confirmed and 16 articles/abstracts focused on 3 drugs
with new modes of action: ustekinumab (UST), secukinumab (SEC) and apremilast
(APR). All were placebo-compared trials and met their primary end point, ACR20.
In 2 studies with UST ACR20 was met by 50% and 44% of patients with UST 90 mg,
42% and 44% with UST 45 mg vs 23% and 20% with placebo, respectively. In two
studies with SEC ACR20 ranged 54% (SEC 300 mg), 50-51% (SEC 150 mg), 29-51% (SEC
75 mg) and 15-17% (placebo). In four studies with APR, ACR20 ranged 32-43% (APR
30 mg), 29-38% (APR 20 mg) and 17-20% (placebo). For all three drugs, no more
withdrawals due to AEs than placebo were seen and, in general, safety appeared
satisfactory. A strategy trial, TIght COntrol of Psoriatic Arthritis (TICOPA),
showed better ACR responses with treatment adaptations upon tight control
compared with standard care.
CONCLUSIONS: UST, SEC and APR are new drugs with efficacy demonstrated for the
treatment of PsA. No major safety signals arise, but long-term studies are
needed. This review informed about the European League Against Rheumatism
recommendations for management of PsA. OBJECTIVE: To review the pharmacology, efficacy, and safety of apremilast and
determine its role relative to other agents in the treatment of psoriasis and
psoriatic arthritis.
DATA SOURCES: A PubMed search (1946 to December 2015) using the terms apremilast
and CC-10004 was conducted to identify relevant articles.
STUDY SELECTION AND DATA EXTRACTION: In vitro or in vivo evaluations of
apremilast published in the English language were eligible for inclusion.
Controlled clinical trials that involved psoriasis or psoriatic arthritis were
selected for review.
DATA SYNTHESIS: Four trials were identified on the treatment of psoriasis. In
those that involved doses of 30 mg twice daily, a significantly greater
percentage of patients receiving apremilast (28.8% to 40.9%) compared with
placebo (5.3% to 5.8%) achieved at least 75% improvement from baseline in
Psoriasis Area and Severity Index score at 16 weeks. Two trials were identified
on the treatment of psoriatic arthritis. In the one that involved a dose of 30
mg twice daily, a significantly greater percentage of patients receiving
apremilast (38.1%) compared with placebo (19.0%) achieved the American College
of Rheumatology criteria for 20% improvement at 16 weeks. In all trials, the
drug had an acceptable safety profile, with the most common adverse effects of
diarrhea, nausea, and headache.
CONCLUSIONS: Apremilast has a novel mechanism of action and is safe and
effective for the management of psoriasis and psoriatic arthritis. At this time,
apremilast should be reserved for patients unable to take disease-modifying
antirheumatic drugs. OBJECTIVE: To evaluate apremilast treatment in patients with active psoriatic
arthritis, including current skin involvement, despite prior therapy with
conventional disease-modifying antirheumatic drugs and/or biologic agents.
METHODS: Patients (N=505) were randomised (1:1:1) to placebo, apremilast 20 mg
twice daily, or apremilast 30 mg twice daily. Rescue therapy with apremilast was
designated at week 16 for placebo patients not achieving 20% improvement in
swollen and tender joint counts. At week 24, the remaining placebo patients were
then randomised to apremilast 20 mg twice daily or 30 mg twice daily. The
efficacy and safety of apremilast were assessed over 52 weeks.
RESULTS: At week 16, significantly more patients receiving apremilast 20 mg
twice daily (28%) and 30 mg twice daily (41%) achieved 20% improvement in
American College of Rheumatology response criteria versus placebo (18%; p=0.0295
and p<0.0001, respectively), and mean decrease in the Health Assessment
Questionnaire-Disability Index score was significantly greater with apremilast
30 mg twice daily (-0.20) versus placebo (-0.07; p=0.0073). In patients with
baseline psoriasis body surface area involvement ≥3%, significantly more
apremilast 30 mg twice daily patients achieved 50% reduction from baseline
Psoriasis Area and Severity Index score (41%) versus placebo (24%; p=0.0098) at
week 16. At week 52, observed improvements in these measures demonstrated
sustained response with continued apremilast treatment. Most adverse events were
mild to moderate in severity; the most common were diarrhoea, nausea, headache
and upper respiratory tract infection.
CONCLUSIONS: Apremilast demonstrated clinically meaningful improvements in
psoriatic arthritis and psoriasis at week 16; sustained improvements were seen
with continued treatment through 52 weeks. Apremilast was generally well
tolerated and demonstrated an acceptable safety profile.
TRIAL REGISTRATION NUMBER: NCT01212770. Phosphodiesterases 4 (PDE4) act as proinflammatory enzymes via degradation of
cAMP, whereas PDE4 inhibitors play an anti-inflammatory role in vitro and in
vivo. In particular, apremilast has been recently approved for the treatment of
psoriasis and psoriatic arthritis. However, little is known on the expression
pattern of PDE4 in psoriasis. We report that PDE4B and PDE4D mRNA are
overexpressed in peripheral blood mononuclear cells (PBMC) from psoriasis, as
compared with normal controls, while apremilast reduces PBMC production of a
number of pro-inflammatory cytokines and increases the levels of
anti-inflammatory mediators. PDE4 expression is up-regulated in psoriatic dermis
as compared with normal skin, with particular regard to fibroblasts. This is
confirmed in vitro, where both dermal fibroblasts (DF) and, to a greater extent,
myofibroblasts (DM) express all PDE4 isoforms at the mRNA and protein level.
Because PDE4 interacts with the nerve growth factor (NGF) receptor CD271 in lung
fibroblasts, we evaluated the relationship and function of PDE4 and CD271 in
normal human skin fibroblasts. All PDE4 isoforms co-immunoprecipitate with CD271
in DM, while apremilast inhibits apoptosis induced by β-amyloid, a CD271 ligand,
in DM. Furthermore, apremilast significantly reduces NGF- and transforming
growth factor-β1 (TGF-β1)-induced fibroblast migration, and inhibits DF
differentiation into DM mediated by NGF or TGF-β1. Finally, in DM, apremilast
significantly reduces cAMP degradation induced by treatment with β-amyloid.
Taken together, these results indicate that PDE4 play an important role in
psoriasis. In addition, the study reveals that the PDE4/CD271 complex could be
important in modulating fibroblast functions. As part of the National Institute for Health and Care Excellence's (NICE) single
technology appraisal (STA) process, apremilast was assessed to determine the
clinical and cost effectiveness of its use in the treatment of moderate to
severe plaque psoriasis in two patient populations, differentiated by the
severity of the patient's Psoriasis Area Severity Index (PASI) score. The Centre
for Reviews and Dissemination (CRD) and the Centre for Health Economics (CHE)
Technology Appraisal Group at the University of York was commissioned to act as
the evidence review group (ERG). This article provides a summary of the
company's submission, the ERG report and NICE's subsequent guidance. In the
company's initial submission, a sequence of treatments including apremilast was
found to be both more effective and cheaper than a comparator sequence without
it in both populations considered. However, this result was found to be highly
sensitive to a series of assumptions made by the company, primarily reflecting
the costs of best supportive care once no further treatments are available, and
the source of utility estimates. A re-estimation of the cost effectiveness of
apremilast by the ERG suggested that the apremilast sequence in the two
populations was more effective, but due to high additional costs was not
indicative of a cost-effective use of NHS resources. As such, in the final
appraisal decision NICE concluded that apremilast was not cost effective in
either population. The diverse clinical picture of PsA suggests the need to identify suitable
therapies to address the different combinations of clinical manifestations. This
review aimed to classify the available biologic agents and new small molecule
inhibitors (licensed and nonlicensed) based on their proven efficacy in treating
different clinical manifestations associated with psoriasis and PsA. This review
presents the level of evidence of efficacy of different biologic treatments and
small molecule inhibitors for certain clinical features of treatment of PsA and
psoriasis, which was graded in categories I-IV. The literature searches were
performed on the following classes of biologic agents and small molecules: TNF
inhibitors (adalimumab, etanercept, infliximab, golimumab, certolizumab),
anti-IL12/IL23 (ustekinumab), anti-IL17 (secukinumab, brodalumab, ixekizumab),
anti-IL6 (tocilizumab), T cell modulators (alefacept, efalizumab, abatacept,
itolizumab), B cell depletion therapy (rituximab), phosphodiesterase 4 inhibitor
(apremilast) and Janus kinase inhibitor (tofacitinib). A comprehensive table
including 17 different biologic agents and small molecule inhibitors previously
tested in psoriasis and PsA was generated, including the level of evidence of
their efficacy for each of the clinical features included in our review (axial
and peripheral arthritis, enthesitis, dactylitis, and nail and skin disease). We
also proposed a limited set of recommendations for a sequential biologic
treatment algorithm for patients with PsA who failed the first anti-TNF therapy,
based on the available literature data. There is good evidence that many of the
biologic treatments initially tested in psoriasis are also effective in PsA.
Further research into both prognostic biomarkers and patient stratification is
required to allow clinicians the possibility to make better use of the various
biologic treatment options available. This review showed that there are many
potentially new treatments that are not included in the current guidelines that
can be used for selected categories of patients based on their disease
phenotype, clinician experience and access to new biologic therapies. Several classes of new oral therapy are in use or in development for the
treatment of psoriasis. Despite the high efficacy of biologics, new oral
therapies remain important as patients generally prefer this mode of
administration and they offer an alternative risk-benefit profile. In this
review, we discuss the novel modes of action of these drugs, including
modulation of cellular pathways involving diverse targets such as Janus kinase,
phosphodiesterase 4, sphingosine 1-phosphate, A3 adenosine receptor and
rho-associated kinase 2. We review the available evidence around licensed drugs
(apremilast) and drugs that are advanced (tofacitinib) or early (ponesimod,
baricitinib, peficitinib, INCB039110, CF101, KD025) in the development pipeline.
The key limitations of these oral therapies are their modest efficacy profile
(apremilast, ponesimod) and the limitations of their safety profile
(tofacitinib, ponesimod), while the evidence for the early pipeline drugs are at
phase II level only. Potential niches of current unmet needs include apremilast
for patients with concomitant psoriatic arthritis, as combination treatments
with biologic therapies, and/or for patients in whom multiple biologic therapies
have failed due to immunogenicity and secondary inefficacy. The present
knowledge gap regarding these novel drugs includes the need for longer clinical
trials or observational studies to evaluate safety, and randomised phase III
trials for the early pipeline drugs. We conclude that further research and data
are necessary to conclusively establish the role of these agents in the current
psoriasis treatment paradigm. INTRODUCTION: A significant portion of patients with psoriasis have scalp and
nail involvement. It has been reported that 40% to 45% of patients with
psoriasis have nail psoriasis, and up to 80% have scalp involvement. Nail and
scalp psoriasis have often been found to be difficult to treat, due to the poor
penetration and poor compliance of topical medication. Oral and biologic
therapies have shown significant efficacy but often with undesirable side
effects. Herein, we analyze the efficacy of apremilast, an oral
phosphodiesterase-4 (PDE-4) inhibitor, in the treatment of nail and scalp
psoriasis at 16-, 32-, and 52 weeks.
METHODS: We reviewed the results of the phase IIb and phase III clinical trials
for apremilast in treating nail and scalp psoriasis.
RESULTS: In ESTEEM 1, patients on apremilast showed a 22.5%, 43.6%, and 60.2%
improvement in NAPSI at weeks 16, 32, and 52. 33.3%, 45.2%, and 63% of patients
achieved NAPSI-50, respectively. In ESTEEM 2, patients on apremilast showed a
29%, 60%, and 59.7% improvement in NAPSI at weeks 16, 32, and 52, with 44.6%,
55.4%, and 68.6% of patients achieving NAPSI-50. In PSOR-005 at week 16,
patients on a dose of 30 mg twice weekly had a 42.9% improvement in NAPSI with
45.5% reaching NAPSI-50. For scalp psoriasis, 46.5%, 37.4%, and 73% of patients
achieved an Sc-PGA of 0 or 1 at weeks 16, 32, and 52 in ESTEEM 1. In ESTEEM 2,
40.9%, 32.4%, and 62.5% of patients achieved an Sc-PGA of 0 or 1 at weeks 16,
32, and 52.
CONCLUSION: With its limited safety profile of only diarrhea and headache and no
additional lab requirements, apremilast may be a safer and more convenient
alternative for patients with severe nail and scalp psoriasis. BACKGROUND: Difficult-to-treat palmoplantar psoriasis has a disproportionately
negative impact on quality of life.
OBJECTIVE: We evaluated the efficacy and safety of apremilast in palmoplantar
psoriasis.
METHODS: A post hoc analysis of data pooled from phase IIb (PSOR-005) and phase
III (Efficacy and Safety Trial Evaluating the Effects of Apremilast in Psoriasis
[ESTEEM] 1 and 2) clinical studies was conducted to determine the effect of
apremilast 30 mg twice daily versus placebo at week 16 in a subset of patients
with moderate to severe plaque psoriasis with active palmoplantar psoriasis
(baseline Palmoplantar Psoriasis Physician Global Assessment [PPPGA] score ≥1).
RESULTS: Significantly more patients taking apremilast with moderate to severe
palmoplantar psoriasis (baseline PPPGA score ≥3) achieved PPPGA score 0 (clear)
or 1 (almost clear) compared with placebo at week 16 (48% vs 27%; P = .021). At
week 16, 46% of the apremilast group with baseline PPPGA score 1 or higher
achieved a PPPGA score of 0 versus 25% of the placebo group (P < .001); 59% of
the apremilast group had a PPPGA score of 0 or 1 with 1-point or more
improvement versus 39% receiving placebo (P < .001).
LIMITATIONS: This post hoc analysis was limited to 16 weeks and did not assess
palmoplantar pustules, lesion localization, or surface area involvement.
CONCLUSION: Apremilast may be a useful oral treatment option for patients with
moderate to severe palmoplantar plaque psoriasis. BACKGROUND: Apremilast, an oral phosphodiesterase 4 inhibitor, has an acceptable
safety profile and is effective for treatment of plaque psoriasis and psoriatic
arthritis.
OBJECTIVES: To evaluate the impact of apremilast on health-related quality of
life (HRQOL), general functioning and mental health using patient-reported
outcome (PRO) assessments among patients with moderate to severe plaque
psoriasis in the ESTEEM 1 and 2 trials.
METHODS: A total of 1255 patients were randomized (2 : 1) to apremilast 30 mg
BID or placebo for 16 weeks; all received apremilast through Week 32. PRO
assessments included the Dermatology Life Quality Index (DLQI), 36-Item
Short-Form Health Survey version 2 mental/physical component summary scores
(SF-36v2 MCS/PCS), Patient Health Questionnaire-8 (PHQ-8), EuroQol-5D (EQ-5D)
and Work Limitations Questionnaire-25 (WLQ-25). Post hoc analyses examined
relationships between Psoriasis Area and Severity Index (PASI) scores and PHQ-8
in the apremilast-treated population at Week 16.
RESULTS: Treatment with apremilast improved all HRQOL PROs at Week 16 (vs.
placebo), except the SF-36v2 PCS, and improvements were sustained through Week
32. Mean DLQI and SF-36v2 MCS improvements exceeded minimal clinically important
differences. Changes at Week 16 in PHQ-8 and PASI were weakly correlated, and
only 35.8% of patients who achieved a ≥75% reduction from baseline in PASI score
(PASI-75) with apremilast treatment also achieved PHQ-8 scores of 0-4.
CONCLUSIONS: Apremilast led to improvements in HRQOL PROs vs. placebo in
patients with moderate to severe plaque psoriasis. |
Is skin color affected by variations of the SLC24A5 gene? | Yes. The alleles of single-nucleotide polymorphisms rs1426654 and rs1834640 (SLC24A5) are associated with light skin pigmentation in Eurasian population. | The recent feasibility of genome-wide studies of adaptation in human populations
has provided novel insights into biological pathways that have been affected by
adaptive pressures. However, only a few African populations have been
investigated using these genome-wide approaches. Here, we performed a
genome-wide analysis for evidence of recent positive selection in a sample of
120 individuals of Wolaita ethnicity belonging to Omotic-speaking people who
have inhabited the mid- and high-land areas of southern Ethiopia for millennia.
Using the 11 HapMap populations as the comparison group, we found
Wolaita-specific signals of recent positive selection in several human leukocyte
antigen (HLA) loci. Notably, the selected loci overlapped with HLA regions that
we previously reported to be associated with podoconiosis-a geochemical
lymphedema of the lower legs common in the Wolaita area. We found selection
signals in PPARA, a gene involved in energy metabolism during prolonged food
deficiency. This finding is consistent with the dietary use of enset, a crop
with high-carbohydrate and low-fat and -protein contents domesticated in
Ethiopia subsequent to food deprivation 10 000 years ago, and with metabolic
adaptation to high-altitude hypoxia. We observed novel selection signals in
CDKAL1 and NEGR1, well-known diabetes and obesity susceptibility genes. Finally,
the SLC24A5 gene locus known to be associated with skin pigmentation was in the
top selection signals in the Wolaita, and the alleles of single-nucleotide
polymorphisms rs1426654 and rs1834640 (SLC24A5) associated with light skin
pigmentation in Eurasian populations were of high frequency (47.9%) in this
Omotic-speaking indigenous Ethiopian population. OBJECTIVES: South Asians exhibit extensive variation in skin melanin index (MI)
which is observed across the broader region of South Asia as well as within
restricted geographic regions. However, the genetic variants associated with
variation in the skin pigmentation phenotype are poorly understood in these
populations. The present study examines the association between MI measures and
genetic variants from 5 candidate pigmentation genes among 533 individuals
representing 6 populations of West Maharashtra.
METHODS: Associations between five single nucleotide polymorphisms (SNPs) known
to play a role in pigmentation (rs1426654-SLC24A5, rs1042602-TYR,
rs16891982-SLC45A2, rs6058017-ASIP, and rs642742-KITLG) and MI measures were
tested using standard one-way analysis of variance (ANOVA) within each
population. Multiple linear regression was used to test the effects of these
SNPs in the full West Maharashtra sample using sex, age, and population or
social group as covariates.
RESULTS: rs1426654 showed significant association with MI in all six study
populations (P < 0.01). Association tests using sex, age, and population as
covariates showed rs1426654 and rs1042602 to be significantly (P < 0.01)
associated with lighter skin pigmentation in West Maharashtra as a whole. By
contrast, when social group was added as a covariate instead of population,
rs1426654, rs1042602, and rs16891982 were significantly (P < 0.01) associated
with lighter skin pigmentation.
CONCLUSIONS: Only rs1426654 is significantly associated with MI in each
individual population; however, rs1426654, rs1042602, and rs16891982 are
significantly associated with pigmentation in the broader West Maharashtra
region after controlling for population and social group, with rs1426654
(SLC24A5) explaining the majority of the observed variation. Am. J. Hum. Biol.
28:610-618, 2016. © 2016 Wiley Periodicals, Inc. |
How are Arboviruses transmitted? | Arboviruses are transmitted by arthropods. | The medical importance, ecology and control of riceland mosquitoes using
alternative strategies is reviewed. Over 135 pest and vector anopheline and
culicine mosquito species found in association with riceland habitats and their
medical importance are presented. Malaria and Japanese encephalitis are the two
most serious human diseases transmitted by riceland mosquitoes, but they have
been incriminated as vectors of dozens of arboviruses and other parasites and
pathogens including the causal agents of West Nile and Rift Valley Fevers and
lymphatic filariasis. Control of vector and pest mosquitoes using chemical
pesticides has generated several problems including: insecticide resistance,
safety risks for humans and domestic animals, and other environmental concerns.
These problems and the high cost and sustainability of programs based
predomitly on conventional insecticides have stimulated increased interest in
integrated control measures in ricelands. The integrated pest management (IPM)
strategy for mosquito control, also known as integrated vector control (IVC), is
an ecologically based approach that may involve several complementary
interventions used in combination or singly. Environmental management, and
chemical, biological and mechanical control, comprise the elements of IVC
proposed for use in or near riceland habitats. Some of the elements of
environmental management include the use of intermittent irrigation; flushing of
fields; use of rice cultivars that require less water; shifting of planting
schedules to avoid optimal mosquito breeding conditions; relocation of
communities or use of dry belt farming around them; and zooprophylaxis and other
personal protection methods, especially use of insecticide-impregnated bed nets.
Biological control agents that have been used successfully in rice fields
include several species of larvivorous fish, a mermithid nematode (Romanomermis
culicivorax), a fungus (Lagenidium giganteum) and bacteria (Bacillus
thuringiensis var. israelensis and Bacillus sphaericus). The mermithid and the
entomopathogens have demonstrated little or no adverse effects on populations of
vertebrate and invertebrate nontarget organisms. The successful use of any
particular method or combination of interventions for the control of riceland
mosquitoes will depend on in-depth ecological studies on the target species and
nontarget organisms, sound geographic reconnaissance and effective routine
sampling and evaluation. When biological control agents are considered,
additional background on the environmental factors limiting their efficacy will
also be needed. In addition to the technical components of the various
interventions employed in integrated control, sustained suppression of riceland
mosquitoes and the diseases they transmit will require a greater sociocultural
supportive background, particularly in developing countries.(ABSTRACT TRUNCATED
AT 400 WORDS) Arboviruses differ from other viruses in their need to replicate in both
vertebrate and invertebrate hosts. The invertebrate is a blood-sucking arthropod
that is competent to transmit the virus between susceptible animals. Arboviruses
transmitted by ticks must adapt to the peculiar physiological and behavioral
characteristics of ticks, particularly with regard to blood feeding, bloodmeal
digestion, and molting. Virus imbibed with the blood meal first infects cells of
the midgut wall. During this phase the virus must contend with the heterophagic
bloodmeal digestion of ticks (an intracellular process occurring within midgut
cells) and overcome the as yet undefined "gut barrier" to infection. Genetic and
molecular data for a number of tick-borne viruses indicate ways in which such
viruses may have adapted to infecting ticks, but far more information is needed.
After infection of midgut cells, tick-borne viruses pass to the salivary glands
for transmission during the next blood-feeding episode. To do this, the virus
must survive molting by establishing an infection in at least one cell type that
does not undergo histolysis. Different tick-borne viruses have different
strategies for surviving the molting period, targeting a variety of tick
tissues. The infection can then persist for the life span of the tick with
little evidence of any detrimental effects on the tick. Transmission to a
vertebrate host during feeding most probably occurs via saliva that contains
virus secreted from infected salivary gland cells. The virus then enters the
skin site of feeding, which has been profoundly modified by the pharmacological
effects of tick saliva. At least three tick-borne viruses exploit such
tick-induced host changes. This phenomenon (saliva-activated transmission) is
believed to underlie "nonviremic transmission," whereby a virus is transmitted
from an infected to an uninfected cofeeding tick through a host that has an
undetectable or very low viremia. Thus tick-borne viruses that have adapted to
the feeding characteristics of their tick vectors may not need to induce a
virulent infection (with high viremia) in their natural vertebrate hosts.
Efficient transmission of tick-borne viruses between cofeeding ticks may be a
means of amplifying virus infection prevalence in F1 generations infected by
transovarial transmission. In the last two to three decades a significant increase of viral zoonotic
infections was observed. These zoonoses are not only newly (or previously
unrecognized) emerging diseases, but also due to the reappearance of diseases
thought to have been defeated (re-emerging diseases). "New" viral diseases can
arise when viruses broaden their host-range (monkey poxvirus; equine
morbillivirus), or can be a consequence of intrinsic properties of the virus
itself, such as high mutation rates (influenza A virus). Most new or reemerging
viral zoonoses are due to infections with hemorrhagic viruses. Many of them are
transmitted by insects (arboviruses, e.g. yellow fever virus) or by rodents
(e.g. Hanta viruses), others by contact with patients and nosocomial infections
(e.g. Ebola virus). The emergence and increase of these diseases are a
consequence of anthropogenic environmental changes, such as distortions of the
ecological balance and changes in agriculture. In addition, the uncontrolled
growth of the cities in tropical and subtropical regions without improvement of
the public health measures and the increasing international animal trade and
travel also favour the spread and recurrence of these diseases. BACKGROUND: There are over 700 known arboviruses and at least 80 immunologically
distinct types that cause disease in humans. Arboviruses are transmitted among
vertebrates by biting insects, chiefly mosquitoes and ticks. These viruses are
widely distributed throughout the world, depending on the presence of
appropriate hosts (birds, horses, domestic animals, humans) and vectors.
Mosquito-borne arboviruses present some of the most important examples of
emerging and resurgent diseases of global significance.
METHODS: A strategy has been developed by which host-range mutants of Dengue
virus can be constructed by generating deletions in the transmembrane domain
(TMD) of the E glycoprotein. The host-range mutants produced and selected
favored growth in the insect hosts. Mouse trials were conducted to determine if
these mutants could initiate an immune response in an in vivo system.
RESULTS: The DV2 E protein TMD defined as amino acids 452SWTMKILIGVIITWIG467 was
found to contain specific residues which were required for the production of
this host-range phenotype. Deletion mutants were found to be stable in vitro for
4 sequential passages in both host cell lines. The host-range mutants elicited
neutralizing antibody above that seen for wild-type virus in mice and warrant
further testing in primates as potential vaccine candidates.
CONCLUSIONS: Novel host-range mutants of DV2 were created that have preferential
growth in insect cells and impaired infectivity in mammalian cells. This method
for creating live, attenuated viral mutants that generate safe and effective
immunity may be applied to many other insect-borne viral diseases for which no
current effective therapies exist. Arthropod-borne viruses (arboviruses) are transmitted to humans primarily
through the bites of infected mosquitoes and ticks. West Nile virus (WNV) is the
leading cause of domestically acquired arboviral disease in the United States.
However, several other arboviruses also cause sporadic cases and seasonal
outbreaks of neuroinvasive disease (i.e., meningitis, encephalitis, and acute
flaccid paralysis). This report summarizes surveillance data reported to CDC in
2013 for WNV and other nationally notifiable arboviruses, excluding dengue.
Forty-seven states and the District of Columbia reported 2,469 cases of WNV
disease. Of these, 1,267 (51%) were classified as WNV neuroinvasive disease, for
a national incidence of 0.40 per 100,000 population. After WNV, the next most
commonly reported cause of arboviral disease was La Crosse virus (LACV) (85
cases), followed by Jamestown Canyon virus (JCV), Powassan virus (POWV), and
eastern equine encephalitis virus (EEEV) (eight). WNV and other arboviruses
continue to cause serious illness in substantial numbers of persons annually.
Maintaining surveillance remains important to help direct and promote prevention
activities. Author information:
(1)MRC - University of Glasgow Centre for Virus Research, Glasgow G11 5JR, UK
The Roslin Institute and Royal (Dick) School of Veterinary Studies, University
of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
[email protected].
(2)Faculty of Science, University of South Bohemia and Biology Centre, Institute
of Parasitology, Czech Academy of Sciences, 37005 České Budějovice (Budweis),
Czech Republic.
(3)The Roslin Institute and Royal (Dick) School of Veterinary Studies,
University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK.
(4)Markey Centre for Structural Biology, Department of Biological Sciences,
Purdue University, West Lafayette IN 47907, USA.
(5)Laboratory of Virology, Wageningen University, 6708 PB Wageningen, The
Netherlands.
(6)Institute of Evolutionary Biology and Centre for Infection Immunity and
Evolution, University of Edinburgh, EH9 3JT, UK.
(7)MRC - University of Glasgow Centre for Virus Research, Glasgow G11 5JR, UK.
(8)Innate Immunity and Pathogenesis Unit, Laboratory of Virology, Rocky Mountain
Laboratories, Division of Intramural Research, National Institute of Allergy and
Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
(9)Centre for Immunity, Infection and Evolution, University of Edinburgh, EH9
3JT, UK.
(10)Unité des Virus Emergents, Faculté de Médicine Timone, 13385 Marseille Cedex
05, France Centre for Hydrology and Ecology, Maclean Building, Oxon OX10 8BB,
UK.
(11)MRC - University of Glasgow Centre for Virus Research, Glasgow G11 5JR, UK
The Roslin Institute and Royal (Dick) School of Veterinary Studies, University
of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK [email protected]. Epizootic congenital abnormalities, encephalomyelitis and febrile illnesses in
cattle caused by arthropod-borne viruses (arboviruses) are prevalent in Japan.
Causative viruses including orthobunyaviruses, orbiviruses and rhabdovirus are
thought to be transmitted by Culicoides biting midges. Recently, the incursions
of several arboviruses, potentially Culicoides-borne, were newly confirmed in
Japan. However, their spread pattern and exact vector species are currently
uncertain. Attempts to isolate arboviruses from Culicoides biting midges and
sentinel cattle were conducted in Kagoshima, located at the southernmost end of
the main islands of Japan, a potentially high-risk area for incursion of
arboviral diseases and outbreak of endemic ones. Seventy-eight isolates
comprising Akabane, Peaton and Sathuperi viruses of the genus Orthobunyavirus of
the family Bunyaviridae, bluetongue virus serotype 16, D'Aguilar virus, Bunyip
Creek virus and epizootic haemorrhagic disease virus serotype 1 of the genus
Orbivirus of the family Reoviridae, a potentially novel rhabdovirus of the genus
Ephemerovirus and unidentified orbivirus-like viruses were obtained from
Culicoides biting midges and sentinel cattle between 2003 and 2013. Akabane,
Sathuperi, D'Aguilar and Bunyip Creek viruses were selectively isolated from
Culicoides oxystoma, suggesting this vector's responsibility for these arbovirus
outbreaks. The results of virus isolation also implied that C. taius,
C. jacobsoni and C. punctatus are competent for the transmission of bluetongue
virus serotype 16, Peaton virus and epizootic haemorrhagic disease virus
serotype 1, respectively. Our monitoring in Culicoides biting midges and
sentinel cattle detected the circulation of Akabane virus just prior to the
accumulations of bovine congenital abnormalities and encephalomyelitis by it
around study sites in 2003, 2006, 2008 and 2013. Silent circulations of the
other arboviruses, including potentially new viruses, were also detected during
the study period. Arboviruses - viruses transmitted by haematophagous arthropods - are responsible
for febrile syndromes, which sometimes include haemorrhagic or neurological
symptoms. Human activities have facilitated the emergence of these originally
zoonotic viruses and the domestication and spread throughout the world of their
major vectors. The last decade has seen significant changes in the epidemiology
of arboviruses transmitted by mosquitoes of the genus Aedes, particularly in
relation to the intercontinental spread of Aedes albopictus. Here, we address
the epidemiological consequences of the invasion by this species into Central
Africa and Europe in a context of viral globalization. The risk of transmission
in these areas is influenced by virus-vector adaptation phenomena as well as
environmental phenomena including climate. Faced with these new risks, it is
essential to develop competences in entomological and virological surveillance,
risk assessment and forecasting of epidemic risk in order to develop strategies
for the prevention and control of epidemics. BACKGROUND: Zika virus (ZIKV) is an arthropod-borne virus (arbovirus)
transmitted by mosquitoes. The potential for ZIKV transmission through blood
transfusion was demonstrated during the ZIKV outbreak that occurred in French
Polynesia from October 2013 to April 2014. Pathogen inactivation of blood
products is a proactive strategy that provides the potential to reduce
transfusion-transmitted diseases. Inactivation of arboviruses by amotosalen and
ultraviolet A (UVA) illumination was previously demonstrated for chikungunya,
West Nile, and dengue viruses. We report here the efficiency of this process for
ZIKV inactivation of human plasma.
STUDY DESIGN AND METHODS: Plasma units were spiked with ZIKV. Viral titers and
RNA loads were measured in plasma before and after amotosalen and UVA
photochemical treatment.
RESULTS: The mean ZIKV titers and RNA loads in plasma before inactivation were
respectively 6.57 log TCID50 /mL and 10.25 log copies/mL. After inactivation,
the mean ZIKV RNA loads was 9.51 log copies/mL, but cell cultures inoculated
with inactivated plasma did not result in infected cells and did not produce any
replicative virus after one passage, nor detectable viral RNA from the second
passage.
CONCLUSION: In this study we demonstrate that amotosalen combined with UVA light
inactivates ZIKV in fresh-frozen plasma. This inactivation process is of
particular interest to prevent plasma transfusion-transmitted ZIKV infections in
areas such as French Polynesia, where several arboviruses are cocirculating. Author information:
(1)Department of Pathology, University of Texas Medical Branch, Galveston, TX
77555, USA.
(2)Department of Entomology, Pennsylvania State University, University Park, PA
16802, USA; The Huck Institutes of the Life Sciences, Pennsylvania State
University, University Park, PA 16802, USA; Center for Infectious Disease
Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
(3)Department of Pathology, University of Texas Medical Branch, Galveston, TX
77555, USA; Institute for Human Infections and Immunity, University of Texas
Medical Branch, Galveston, TX 77555, USA. Electronic address: [email protected]. Arboviruses transmitted by mosquitoes are a major cause of human disease
worldwide. The absence of vaccines and effective vector control strategies has
resulted in the need for novel mosquito control strategies. The endosymbiotic
bacterium Wolbachia has been proposed to form the basis for an effective
mosquito biocontrol strategy. Resident strains of Wolbachia inhibit viral
replication in Drosophila fruit flies and induce a reproductive phenotype known
as cytoplasmic incompatibility that allows rapid invasion of insect populations.
Transinfection of Wolbachia strains into the principle mosquito vector of dengue
virus, Stegomyia aegypti, has resulted in dengue-refractory mosquito lines with
minimal effects on mosquito fitness. Wolbachia strains have now been established
in wild St. aegypti populations through open releases in dengue-endemic
countries. In this review, we outline the current state of Wolbachia-based
biocontrol strategies for dengue and discuss the potential impact of resident
Wolbachia strains for additional target mosquito species that transmit
arboviruses. Arboviruses are arthropod-borne viruses that exhibit worldwide distribution,
contributing to systemic and neurologic infections in a variety of geographical
locations. Arboviruses are transmitted to vertebral hosts during blood feedings
by mosquitoes, ticks, biting flies, mites, and nits. While the majority of
arboviral infections do not lead to neuroinvasive forms of disease, they are
among the most severe infectious risks to the health of the human central
nervous system. The neurologic diseases caused by arboviruses include
meningitis, encephalitis, myelitis, encephalomyelitis, neuritis, and myositis in
which virus- and immune-mediated injury may lead to severe, persisting
neurologic deficits or death. Here we will review the major families of emerging
arboviruses that cause neurologic infections, their neuropathogenesis and host
neuroimmunologic responses, and current strategies for treatment and prevention
of neurologic infections they cause. Diseases caused by arboviruses transmitted by Aedes aegypti, such as dengue,
chikungunya and Zika continue to rise in annual incidence and geographic
expansion. A key limitation for achieving control of Ae. aegypti has been the
lack of effective tools for monitoring its population, and thus determine what
control measures actually work. Surveillance of Ae. aegypti has been based
mainly on immature indexes, but they bear little relation to the number of
mosquito females, which are the ones capable of transmitting the viruses. The
recent development of sampling techniques for adults of this vector species
promises to facilitate surveillance and control activities. In this review, the
various monitoring techniques for this mosquito are presented, along with a
discussion of their usefulness, and recommendations for improved entomological
surveillance. |
Which bacterium has the smallest genome in base pairs yet found? | Our results reveal that Nasuia-ALF has the smallest bacterial genome yet sequenced (112 kb), and that the Sulcia-ALF genome (190 kb) is smaller than that of Sulcia in other insect lineages. Both regions exhibit a significant reduction in length and gene number in B. aphidicola BCc, as it could be expected since it possess the smallest bacterial genome. We sequenced genomes of the obligate symbionts, Sulcia muelleri and Nasuia deltocephalinicola, of the phloem-feeding pest insect, Macrosteles quadrilineatus (Auchenorrhyncha: Cicadellidae). | Many insects rely on bacterial symbionts with tiny genomes specialized for
provisioning nutrients lacking in host diets. Xylem sap and phloem sap are both
deficient as insect diets, but differ dramatically in nutrient content,
potentially affecting symbiont genome evolution. For sap-feeding insects,
sequenced symbiont genomes are available only for phloem-feeding examples from
the suborder Sternorrhyncha and xylem-feeding examples from the suborder
Auchenorrhyncha, confounding comparisons. We sequenced genomes of the obligate
symbionts, Sulcia muelleri and Nasuia deltocephalinicola, of the phloem-feeding
pest insect, Macrosteles quadrilineatus (Auchenorrhyncha: Cicadellidae). Our
results reveal that Nasuia-ALF has the smallest bacterial genome yet sequenced
(112 kb), and that the Sulcia-ALF genome (190 kb) is smaller than that of Sulcia
in other insect lineages. Together, these symbionts retain the capability to
synthesize the 10 essential amino acids, as observed for several symbiont pairs
from xylem-feeding Auchenorrhyncha. Nasuia retains genes enabling synthesis of
two amino acids, DNA replication, transcription, and translation. Both symbionts
have lost genes underlying ATP synthesis through oxidative phosphorylation,
possibly as a consequence of the enriched sugar content of phloem. Shared
genomic features, including reassignment of the UGA codon from Stop to
tryptophan, and phylogenetic results suggest that Nasuia-ALF is most closely
related to Zinderia, the betaproteobacterial symbiont of spittlebugs. Thus,
Nasuia/Zinderia and Sulcia likely represent ancient associates that have
co-resided in hosts since the divergence of leafhoppers and spittlebugs >200 Ma,
and possibly since the origin of the Auchenorrhyncha, >260 Ma. |
Which are the triad symptoms of pheochromocytoma? | The classic triad of symptoms are episodic headache, excessive sweating (diaphoresis) and palpitation. | A right adrenal tumor was found incidentally by renal echography in a
25-year-old man, who had been on hemodialysis for 4 years. Inquiry and clinical
examination suggested pheochromocytoma, which was confirmed by plasma
catecholamine measurements. Subsequent adrenalectomy was uneventful. Although
hypertension, headache, and diaphoresis are common symptoms in a dialyzed
patient, pheochromocytoma has to be eliminated in the presence of this clinical
triad. Pheochromocytoma is an unusual but potentially devastating tumor. Although a
high index of suspicion is necessary, the likelihood of a pheochromocytoma is
lower in the absence of the typical symptoms and findings. Nonetheless,
screening must be broadened to include patients with a lower risk of the
disease, such as those with resistant or labile hypertension who are minimally
symptomatic. Extensive diagnostic evaluations should be reserved for those whose
clinical or laboratory findings are more suggestive. Symptoms in a group of
patients in whom a pheochromocytoma was seriously considered but excluded
overlap symptoms in patients with a pheochromocytoma. Certain symptoms are
useful: flushing to suggest a non-pheochromocytoma illness; visual symptoms,
flank pain, and pallor to suggest that a pheochromocytoma is more likely.
Combinations of symptoms can be of value: 2 or more symptoms from the triad of
headache, palpitations, and diaphoresis were present in the majority of
pheochromocytoma patients, but in a smaller number of non-pheochromocytoma
patients. The presence of the entire triad is more specific, but less sensitive.
New hypertension, or hypertension associated with unexplained orthostatic
hypotension, are suggestive of an underlying pheochromocytoma. Twenty-four-hour
urine studies are consistently abnormal in patients with a pheochromocytoma, but
are also elevated in a significant proportion of non-pheochromocytoma patients.
Values greater then 1.5-2-fold above the upper limit of normal are very
suggestive that a pheochromocytoma is present, and warrant a more intensive
subsequent evaluation. Imaging studies are reliable in the diagnosis of
pheochromocytoma, and can help to confirm or exclude the disease. Patients with
a higher clinical likelihood and any elevated urinary testing, or with a lower
clinical likelihood and persistently and/or significantly elevated urinary
testing, should have imaging studies performed. This combination of clinical
screening, 24-hour urinary testing, and imaging studies is a useful and reliable
approach to patients suspected of harboring a pheochromocytoma. Pheochromocytoma is a catecholamine secreting tumor originating from the adrenal
medulla (up to 90%), or from the chromaffin tissue along the paravertebral
sympathetic chain. The hallmark of pheochromocytoma is paroxysmal hypertension
associated with diaphoresis, headache, tremulousness, and palpitations. The
triad of diaphoresis, tachycardia, and headache in hypertensive patients is
highly suggestive of pheochromocytoma. Other symptoms like flushing, nausea,
vomiting, personality changes, and visual disturbances may however cast doubt on
the diagnosis of pheochromocytoma. Death resulting from pheochromocytoma is
usually due to congestive heart failure, myocardial infarction, or intracerebral
hemorrhage. Although less than 0.1 percent of patients with hypertension have a
pheochromocytoma, nearly 50 percent of the mortality with unsuspected
pheochromocytoma occurred during anesthesia and surgery or parturition. Patients
of unsuspected pheochromocytoma have higher risk for surgery, because some
mandatory pre-op medical treatments might have been ignored. It is also a
challenge to anesthesiologists to handle unsuspected hypertensive crisis during
anesthesia and surgery. We presented such a case of unexpected Pheochromocytoma
which was mis-diagnosed by the surgeon and was treated as an ordinary adrenal
gland tumor and was scheduled for surgical operation. When the patient was
undergoing excision of the tumor, manipulations of the tumor initiated an
tremendous elevation of the blood pressure. Upon reviewing her history of
normotension with visual disturbance, nausea and restlessness, she was immediate
treated as with a pheochromocytoma. Appropriate managements were applied to
control her abnormally high fluctuating blood pressure with success and with no
complications or adverse effect.(ABSTRACT TRUNCATED AT 250 WORDS) BACKGROUND: Hypertension is the most common medical complication of pregcy.
Pheochromocytoma in pregcy is rare, and if unrecognized, can cause serious
perinatal morbidity and mortality.
METHODS: A patient with severe hypertension, postpartum pulmonary edema, and a
recognized pheochromocytoma is described.
RESULTS: Abdominal palpation after vaginal childbirth reproduced the diagnostic
triad of hypertension, headaches, and palpitations. Magnetic resoce imaging
established the correct diagnosis before biochemical confirmation of excess
catecholamine production. The patient responded to alpha-adrenergic receptor
blockade with control of her severe hypertension and clearing of pulmonary
edema. The best time to diagnose a pheochromocytoma is before delivery because
vaginal childbirth stimulates the release of lethal amounts of catecholamines.
CONCLUSIONS: The physician who delivers babies must distinguish between labile
hypertension and paroxysmal hypertension. Most experts believe that a
spontaneous vaginal delivery is contraindicated when the patient has a
pheochromocytoma. Postpartum pulmonary edema associated with a pheochromocytoma
is unusual. The profound pressor response elicited by palpation of the
postpartum abdomen, the failure of medications usually effective in the
treatment of a hypertensive crisis, and the use of magnetic resoce imaging to
confirm a functioning adrenal adenoma are the features unique to this case. INTRODUCTION: Pheochromocytomas are most commonly tumours of adrenal medullary
origin. Pheochromocytoma by definition produces and secretes catecholamines.
Similar tumours that do not secrete active substances of any kind are called non
functioning paragangliomas. The hallmark clinical manifestation of
pheochromocytoma is hypertension accompanied with various signs and symptoms in
excess of catecholamines or other bioactive substances. The early diagnosis of
pheochromocytoma is important not only because it offers the possibility of
curing hypertension but also because unrecognised pheochromocytoma is a
potentially lethal condition. The aim of this article is to stress the specify
of the clinical finding, diagnostical values of the laboratory tests and
possibilities of morphological localizing techniques in a series of 98 patients
with surgically proven pheochromocytoma.
RESULTS: Over the period from 1954 to 2002 pheochromocytoma was diagnosed and
surgically treated in 98 patients. The diagnosis was confirmed at operation
except in patients who refused operation or continued the examination in other
Clinical wards. There were 59 females and 48 males (F:M = 1.23:1), the age
ranged from 7 to 64 years with the pick incidence in the second and third
decades of life in males and the third and fourth decades of life in females.
The basic clinical characteristic was hypertension which was found in 94% of
patients with an approximately equal frequency of fixed and paroxysmal
hypertension cases. The most often accompanning manifestations were headache
(62%), perspiration (61%) and palpitations (65%). A high level of vanyl mandelic
acid (VMA) and free catecholamines in 24-hour urine collection confirmed the
diagnosis in 94% of cases. In boderline cases we performed dynamic tests, the
most relevant among them being the test with phentolamin. It was positive in 95%
of patients. Retropneumothomography contributed to a successful localisation of
tumour in 83% of cases. Computed tomography (CT) was performed in 69 patients
and was positive in 97% of them. Magnetic resoce imaging (MRI) localized the
tumour in all 16 patient in whom it was performed. The whole body MIBG-J-131
(metaiodobenzylguanidine) scanes were positive in 92% (45/49) and false negative
in the remainder of 8% (4/49) of cases. Selective angiography was performed in
40 patients and in all it was positive.
DISCUSSION: Although pheochromocytomas were among the first recognized adrenal
tumours, the prompt and safe diagnosis is mandatory up to date. The average
annual incidence has been estimated by several epidemiologic studies to range
from 0.8 to between 1.55 and 2.1 million persons per year. It is reported that
it is curable cause of hypertension in 0.1% to 1% of cases. Pheochromocytoma has
been classified as a "10% tumour" because various studies have shown that each
of the characteristics mentioned bellow occurs with a frequency of approximately
10%: bilateral, extra-adrenal, multiple, maligt, familial and occurring in
children. Our series of patients has a similar distribution: pheochromocytoma
was in 9.2% of patients extra-adrenal, in 7.1% bilateral, in 9.2% multiple and
in 4.08% maligt. Hypertension was the constant finding in 94% of our
patients. Three clinical patterns of hypertenson have been observed. The first
is paroxysmal hypertension, and the others are fixed or combinations of fixed
and paroxysmal hypertension. According to our experience there were the equal
incidence of all forms of hypertension. We noticed, like others, when the triad
of headache, sweating and palpitations is accompanied by hypertension, the
diagnosis of pheochromocytoma can be made with specify and sensitivity over 93%.
In absence of this finding the diagnosis can be excluded with certainty of 99%.
As a specify of the clinical finding, we mention two patients with
manifestations of hypercorticism, two patients with pheochromocytoma of the
urinary bladder, and four with MEN syndrome (one with MEN 2A and three with MEN
2B). For confirming the diagnosis the most relevant laboratory test was the
higher level of VMA and free catecholamines in 24-hour urine collections. Once
pheochromocytoma has been diagnosed by biochemical analyses, the anatomic
location of the tumour or tumors must be determined. Currently, the best
approach is to obtain MIBG-J-131 scan and then to perform MRI or CT of the
abdomen and other areas identified on MIBG scan in order to provide more
accurate spatial information. With this approach the great majority of
pheochromocytomas can be localized.
CONCLUSION: There is no classic picture, no stereotype for pheochromocytoma,
although the history and physical finding are helpful. Patients come to the
clinician in a variety of ways and settings. They may have classic attacks of
hypertension accompanied with headache, perspiration and paplpitations or they
may have identical symptoms and physical findings as the patients with primary
hypertension. On the other hand, they may have signs and symptoms of diabetes
mellitus, hyperthyroidism, hypercalcaemia, congestive heart failure, myocardial
infarction, maligt hypertension or a variety of other conditions. Rarely,
they have no complaints at all. Once the diagnosis was made, spatial localizing
of the tumour or tumours, and surgical treatment are necessary. Unrecognized
disease may be fatal. Sporadic pheochromocytoma is a rare tumor of childhood and accounts for less
than 1% of cases of hypertension. We describe the presentation and outcome of 19
adolescents with sporadic pheochromocytoma seen over past 10 years at a tertiary
care center in north India. The mean age (+/- SD) at presentation was 15.1 +/-
2.4 years with range from 9-18 years. The male to female ratio was 12:7. The lag
time between onset of symptoms to diagnosis ranged from 1 month to 5 years with
mean (+/- SD) of 1.09 +/- 1.02 years. The majority of children presented with
hypertension and paroxysms. Paroxysms, characterized by the triad of headache,
palpitations and sweating, was present in 13 (68%) of these patients. Twelve
(63%) patients had postural fall in blood pressure, ten (53%) had abdominal
pain, four (21%) had visual blurring, and three (16%) each had palpable
abdominal mass and significant weight loss at presentation. Nausea and vomiting
are common symptoms in children with pheochromocytoma and were present in six
(32%) and three (16%) patients, respectively. Café-au-lait macule was present in
only two (11%) patients. Urinary vanilyl mandelic acid (VMA) was found to be
significantly high in ten (53%) patients, and urinary epinephrine and
norepinephrine in eight (42%). Six (32%) patients had both VMA and urinary
epinephrine and norepinephrine within normal limits and five (26%) had
significant elevation of both. The tumor was localized by ultrasonography in 17
(89%) patients and by computed tomography in 18 (95%), and in one patient it was
localized by 131I-MIBG scan. Sixteen (84%) patients had adrenal pheochromocytoma
(including four with bilateral masses), while the remaining three (16%) had
abdominal extra-adrenal pheochromocytoma originating from sympathetic ganglions.
The mean (+/- SD) diameter of the tumor was 4.4 +/- 1.7 cm, ranging from 2.2-7.5
cm. Pre-operatively, hypertension was managed by phenoxybenzamine in six (32%),
sustained release prazosin in 12 (63%), beta-blockers in 14 (74%), calcium
channel blockers in 12 (63%), and angiotensin converting enzyme inhibitors and
diuretics in only two (11%) patients. Eighteen (85%) patients underwent
exploratory laparotomy for removal of the tumor. On follow-up, 13 (72%) patients
became normotensive, while six (32%) patients continued to have hypertension. In
conclusion, childhood pheochromocytoma is characterized by atypical
symptomatology; ultrasonography is a useful modality in localizing the lesions
in the majority of patients; surgery is rewarding in most patients. Pheochromocytoma (Pheo) is a rare cause of hypertension (HTN). Classically, a
triad of symptoms includes sweating, palpitations, and headache. HTN is often
present and labile. Although a triad of symptoms is cited as the most frequent
presenting complaints, our clinical experience leads us to question how often
these are present. Thirty-two patients with histologically proven pheo or
paraganglionoma were evaluated. Around 84.4% patients had adrenal pheos and
15.6% had extra-adrenal pheos. Two patients had bilateral adrenal tumors, two
had a history of prior pheos, and four had a family history of pheo. There were
19 (59.4%) female and 13 (40.6%) male patients. Six (18.7%) patients were black
and 26 (81.3%) were white. The mean age at presentation was 43.2+/-13.9 years.
Two patients were known to have neurofibromatosis type 1, two had von
Hippel-Lindau disease, one had multiple endocrine neoplasia 2A, and one PGL/SDHD
genetic mutation. Twenty-six patients had sporadic tumors or had not had genetic
testing. Biochemical diagnosis was confirmed with 24-h urine measurements. Urine
catecholamine measurements were elevated at least 2 to 4 times above normal
levels. Mean SBP readings at presentation were 128+/-19 mmHg. Mean DBP readings
were 81+/-13 mmHg. Around 65.6% patients were hypertensive at presentation.
Fifty percent of the patients had palpitations, 40.6% had tachycardia, 34.4% had
sweating, and 31.3% had headaches. Initial presenting symptoms were diverse.
Pheo is a rare clinical entity and remains a huge diagnostic challenge for all
clinicians. Pheochromocytoma can mimic a number of other diseases, and that's why it is hard
to diagnose. The classic triad of symptoms are episodic headache, excessive
sweating and palpitation. Hereby I present a case without any symptoms mentioned
above. A 58-year-old patient with controlled hypertension without any previous
complaints connected with respiratory tract, was admitted to hospital because of
round shadows found in chest X-ray. The attempts to find initial focus as a
basis of neoplasma failed. Postmortal histologic examination of the adrenal
glands revealed pheochromocytoma with multiple focuses in lungs and mediastinal
lymph nodes. Diagnosis pheochromocytoma was as surprising for the physicians as
for pathologists despite the presence of a small tumor of the left adrenal gland
found previously in CT scan of the abdomen. In case of presence of "round
shadows" in lungs connected with changes in adrenal glands one ought to think
about pheochromosytoma. Pheochromocytoma is a rare catecholamine-producing tumor arising from chromaffin
tissue in the adrenal medulla, occurring in less than 0.2 percent of patients
with hypertension. The mean age at diagnosis is about 40 years.
Pheochromocytomas are commonly inherited as features of multiple endocrine
neoplasia type 2 or several other pheochromocytoma-associated syndromes and have
variable clinical presentation. Among the presenting symptoms, episodes of
palpitations, headaches, and profuse sweating are typical and constitute a
classic triad. We report a case of a 17-year-old male patient with rare
bilateral pheochromocytoma presenting with persistent hiccups for 4 months and
blurring of vision for 1 week, later followed by hypertensive crisis. There was
neither family history of pheochromocytoma nor any classic symptoms. Patient was
diagnosed with bilateral pheochromocytoma without any syndromic association. But
still this patient needs to be followed for future development of medullary
carcinoma of thyroid because it could be an initial presentation of MEN
2A/2B/VHL syndromes. Our paper highlights the importance of maintaining a high
level of suspicion for persistent hiccups and careful clinical screening for
hypertension even in absence of associated syndromes of pheochromocytoma and
classical symptoms to achieve prompt diagnosis and to avoid improper management. Autoimmune polyendocrine syndrome type II (APS-II) is the most common
immunoendocrinopathy syndrome. APS-II is defined by the development of two or
more of the following entities: primary adrenal insufficiency (Addison's
disease), Graves' disease, type 1A diabetes mellitus, autoimmune thyroiditis,
primary hypogonadism, celiac disease, and myasthenia gravis. Other frequent
clinical findings are vitiligo, alopecia, pernicious anemia and/or serositis.
Primary adrenal insufficiency in these patients affects the adrenal cortex,
which is destroyed by autoantibodies against 21-hydroxylase. Unlike other causes
of adrenal insufficiency (infectious diseases, infiltrative diseases, bleeding,
tumors), the adrenal medulla is not involved. Pheochromocytomas are tumors
arising from the chromaffin cells of the sympathetic nervous system in the
adrenal medulla. The clinical symptoms of these tumors vary from isolated
hypertension or hypertension accompanied by paroxysmal episodes -including the
classical triad of headache, palpitations and diaphoresis-to potentially serious
manifestations such as acute pulmonary edema, arrhythmias and sudden death.
Nevertheless, up to 40% of affected patients are asymptomatic. We present the
case of a patient diagnosed with APS-II who developed a pheochromocytoma. In
this patient, the adrenal gland cortex was atrophied and the tumor was attached
to the adrenal medulla. This coexistence of endocrinopathies, with no etiologic
connection, is a surprising finding, which has not previously been described in
the current literature. Pheochromocytoma is a rare catecholamine secreting neuroendocrine tumor with an
estimated annual incidence of one to four per million and prevalence among
hypertensive patients of 0.1 to 0.6%. The symptoms and signs of pheochromocytoma
include the classic triad of episodic headache, increased sweating, and
palpitations. These are as a result of an uncontrolled release of
catecholamines. There exist only a small number of reports of pheochromocytoma
simulating hypertrophic obstructive cardiomyopathy, few reports of
pheochromocytoma-induced ischemic stroke and only two reported cases with
pheochromocytoma-induced arterial thrombosis. We present a case of multiple,
rare clinical complications of pheochromocytoma occurring in the same patient
and the review of literature of these complications. OBJECTIVE: The purpose of this study was to determine the spectrum of imaging
appearances of pheochromocytoma and the associated clinical and biochemical
features.
MATERIALS AND METHODS: In this retrospective study, a citywide pathology
database (2000-2011) was searched to identify the records of patients with
pheochromocytoma. The search yielded the cases of 53 patients (28 men, 25 women;
mean age, 50 years). The institutional PACS and radiology information system
records, hospital charts, and the provincial electronic health records of these
patients were reviewed. Imaging appearances and clinical and biochemical
features related to pheochromocytomas were recorded.
RESULTS: One chart was not available for review. In the 52 cases analyzed, 40 of
the patients had symptoms: 31 patients had hypertension; 10 had the triad of
palpitations, diaphoresis, and headaches; and all had elevated urinary
metanephrine concentrations. Seven patients had a familial syndrome, and five
had bilateral pheochromocytomas. One patient had an extraadrenal
pheochromocytoma, and five had maligt tumors. The mean size of
pheochromocytomas was 4.0 cm. Most pheochromocytomas were heterogeneous (CT,
56%; MRI, 65%; ultrasound, 45%) and were MIBG positive (90%). Eleven of 34 (32%)
pheochromocytomas had T2 signal intensity greater than that of the spleen. Most
pheochromocytomas were less enhancing than the spleen (CT, 85%; MRI, 71%).
Contrast-enhanced CT was performed on 33 tumors, of which 20 enhanced less than
the spleen and 8 showed similar enhancement to the spleen; contrast-enhanced MRI
was performed on 24 tumors, of which 12 enhanced less than the spleen and 5
showed similar enhancement to the spleen. Predomit cystic change was found in
4 of 20 (20%) ultrasound, 9 of 41 (22%) CT, and 11 of 34 (32%) MRI examinations.
Eight of 34 (24%) pheochromocytomas were hemorrhagic, two (5%) had
calcifications, and three of six were PET positive. Two cystic pheochromocytomas
and one lipid-containing pheochromocytoma were misdiagnosed as adrenal adenomas.
CONCLUSION: Most pheochromocytomas were heterogeneous at imaging, were MIBG
positive, accompanied elevated urinary metanephrine concentrations, and were
symptomatic. High T2 signal intensity was found in approximately one third of
solid tumors. Atypical imaging features included homogeneity, cystic change,
hemorrhage, intense enhancement, calcifications, intracellular lipid,
bilaterality, and maligcy. BACKGROUND: Pheochromocytomas are catecholamine producing tumors that
classically present with the triad of sweating, palpitations and headache.
CASE CHARACTERISTICS: 9-year-old boy whose only presenting complaints were
polyuria and polydipsia for 2 years.
OBSERVATION: Routine measurement of blood pressure detected mild hypertension,
and subsequent investigations revealed bilateral pheochromocytoma.
OUTCOME: Surgical removal of the tumors resulted in complete resolution of
polyuria and polydipsia.
MESSAGE: The case highlights the importance of measuring BP for children as part
of physical examination. CONTEXT: Pheochromocytoma is a rare disease but with high mortality if it is not
being diagnosed early. Several biochemical tests with high accuracy have been
obtained, but the clinical threshold for request of these tests is not
determined clearly.
OBJECTIVES: To determine the Likelihood Ratios of clinical symptoms and signs in
diagnosing pheochromocytoma. And also meta-analysis of their sensitivity in this
disease.
DATA SOURCES: MEDLINE was searched for relevant English-language articles dated
1960 to February 2014. Bibliographies were searched to find additional articles.
STUDY SELECTION: We included original studies describing the sensitivity and/or
likelihood ratios of signs and symptoms in clinical suspicion of
pheochromocytoma. Their method of diagnosis should have been based on pathology.
We excluded specific subtypes or syndromes related to pheochromocytoma, or
specific ages or gender. Also we excluded studies before 1993 (JNC5) which no
definition of hypertension was presented. 37 articles were chosen finally.
DATA EXTRACTION: Two authors reviewed data from articles independently and gave
discrepancies to third author for decision. The aim was extraction of raw
numbers of patients having defined signs or symptoms, and draw 2 × 2 tables if
data available. We meta-analyzed sensitivities by Statsdirect and Likelihood
Ratios by Meta-disc soft wares. Because our data was heterogeneous based on
I(2) > 50 % (except negative Likelihood ratio of hypertension), we used random
effect model for doing meta-analysis. We checked publication bias by drawing
Funnel plot for each sign/symptom, and also Egger test.
DATA SYNTHESIS: The most prevalent signs and symptoms reported were hypertension
(pooled sensitivity of 80.7 %), headache (pooled sensitivity of 60.4 %),
palpitation (pooled sensitivity of 59.3 %) and diaphoresis (pooled sensitivity
of 52.4 %). The definition of orthostatic hypotension was different among
studies. The sensitivity was 23-50 %. Paroxysmal hypertension, chest pain,
flushing, and weakness were the signs/symptoms which had publication bias based
on Funnel plot and Egger test (P value < 0.05). Seven of the articles had
control group, and could be used for calculating LR of signs/symptoms.
Diaphoresis (LR+ 2.2, LR- 0.45), Palpitation (LR+ 1.9, LR- 0.52) and headache
(LR+ 1.6, LR- 0.24) were significant symptoms in clinical diagnosis of
pheochromocytoma. Other signs and symptoms had been reported in only one study
and could not have been meta-analyzed. Classic triad of headache, palpitation
and diaphoresis in hypertensive patients had the LR+ 6.312 (95 % CI
0.217-183.217) and LR- 0.139 (95 % CI 0.059-0.331). Surprisingly, hypertension
was not important in clinical suspicion of pheochromocytoma, and even
normotension increased the probability of the disease.
CONCLUSIONS: By available data, there is no single clinical finding that has
significant value in diagnosis or excluding pheochromocytoma. Combination of
certain symptoms, signs and para-clinical exams is more valuable for physicians.
Further studies should be done, to specify the value of clinical findings. Until
that time the process of diagnosis will be based on clinical suspicion and lab
tests followed by related imaging. |
List the types of the Cardiorenal syndrome (CRS) according to the five-part classification system. | Cardiorenal syndromes (CRS) have been recently classified into five distinct entities, each with different major pathophysiologic mechanisms.
CRS type 1: acute worsening of heart function (AHF-ACS) leading to kidney injury and/or dysfunction.
CRS type 2: chronic abnormalities in heart function (CHF-CHD) leading to kidney injury or dysfunction.
CRS type 3: acute worsening of kidney function (AKI) leading to heart injury and/or dysfunction.
CRS type 4: chronic kidney disease (CKD) leading to heart injury, disease and/or dysfunction.
CRS type 5: systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney. | The term cardiorenal syndrome (CRS) increasingly has been used without a
consistent or well-accepted definition. To include the vast array of
interrelated derangements, and to stress the bidirectional nature of
heart-kidney interactions, we present a new classification of the CRS with 5
subtypes that reflect the pathophysiology, the time-frame, and the nature of
concomitant cardiac and renal dysfunction. CRS can be generally defined as a
pathophysiologic disorder of the heart and kidneys whereby acute or chronic
dysfunction of 1 organ may induce acute or chronic dysfunction of the other.
Type 1 CRS reflects an abrupt worsening of cardiac function (e.g., acute
cardiogenic shock or decompensated congestive heart failure) leading to acute
kidney injury. Type 2 CRS comprises chronic abnormalities in cardiac function
(e.g., chronic congestive heart failure) causing progressive chronic kidney
disease. Type 3 CRS consists of an abrupt worsening of renal function (e.g.,
acute kidney ischemia or glomerulonephritis) causing acute cardiac dysfunction
(e.g., heart failure, arrhythmia, ischemia). Type 4 CRS describes a state of
chronic kidney disease (e.g., chronic glomerular disease) contributing to
decreased cardiac function, cardiac hypertrophy, and/or increased risk of
adverse cardiovascular events. Type 5 CRS reflects a systemic condition (e.g.,
sepsis) causing both cardiac and renal dysfunction. Biomarkers can contribute to
an early diagnosis of CRS and to a timely therapeutic intervention. The use of
this classification can help physicians characterize groups of patients,
provides the rationale for specific management strategies, and allows the design
of future clinical trials with more accurate selection and stratification of the
population under investigation. The term 'cardiorenal syndrome' (CRS) has increasingly been used in recent years
without a constant meaning and a well-accepted definition. To include the vast
array of interrelated derangements, and to stress the bidirectional nature of
the heart-kidney interactions, the classification of the CRS today includes 5
subtypes whose etymology reflects the primary and secondary pathology, the time
frame and simultaneous cardiac and renal codysfunction secondary to systemic
disease. The CRS can generally be defined as a pathophysiological disorder of
the heart and kidneys whereby acute or chronic dysfunction in one organ may
induce acute or chronic dysfunction in the other organ. Type I CRS reflects an
abrupt worsening of cardiac function (e.g. acute cardiogenic shock or
decompensated congestive heart failure) leading to acute kidney injury. Type II
CRS describes chronic abnormalities in cardiac function (e.g. chronic congestive
heart failure) causing progressive and permanent chronic kidney disease. Type
III CRS consists in an abrupt worsening of renal function (e.g. acute kidney
ischemia or glomerulonephritis) causing acute cardiac disorder (e.g. heart
failure, arrhythmia, ischemia). Type IV CRS describes a state of chronic kidney
disease (e.g. chronic glomerular disease) contributing to decreased cardiac
function, cardiac hypertrophy and/or increased risk of adverse cardiovascular
events. Type V CRS reflects a systemic condition (e.g. diabetes mellitus,
sepsis) causing both cardiac and renal dysfunction. Biomarkers can help to
characterize the subtypes of the CRS and to indicate treatment initiation and
effectiveness. The identification of patients and the pathophysiological
mechanisms underlying each syndrome subtype will help to understand clinical
derangements, to make the rationale for management strategies and to design
future clinical trials with accurate selection and stratification of the studied
population. The term cardiorenal syndrome (CRS) has increasingly been used in recent years
without a constant meaning and a well accepted definition. To include the vast
array of interrelated derangements, and to stress the bi-directional nature of
the heart-kidney interactions, the classification of the cardiorenal syndrome
includes today five sub-types whose etymology reflects the primary and secondary
pathology, the time-frame and simultaneous cardiac and renal co-dysfunction
secondary to systemic disease. The cardiorenal syndrome can be generally defined
as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic
dysfunction in one organ may induce acute or chronic dysfunction in the other
organ. Type I CRS reflects an abrupt worsening of cardiac function (e.g. acute
cardiogenic shock or decompensated congestive heart failure) leading to acute
kidney injury. Type II CRS describes chronic abnormalities in cardiac function
(e.g. chronic congestive heart failure) causing progressive and permanent
chronic kidney disease. Type III CRS consists in an abrupt worsening of renal
function (e.g. acute kidney ischaemia or glomerulonephritis) causing acute
cardiac disorder (e.g. heart failure, arrhythmia, ischemia). Type IV CRS
describes a state of chronic kidney disease (e.g. chronic glomerular disease)
contributing to decreased cardiac function, cardiac hypertrophy and/or increased
risk of adverse cardiovascular events. Type V CRS reflects a systemic condition
(e.g. diabetes mellitus, sepsis) causing both cardiac and renal dysfunction.
Biomarkers can help to characterize the subtypes of the CRS and to indicate
treatment initiation and effectiveness. To include the vast array of interrelated derangements and to stress the
bidirectional nature of the heart-kidney interactions, the classification of the
cardiorenal syndrome today includes 5 subtypes whose terminology reflects their
primary and secondary pathology, time frame, and the presence of concomitant
cardiac and renal dysfunction. Cardiorenal syndromes (CRSs) are pathophysiologic
disorders of the heart and kidneys whereby acute or chronic dysfunction of one
organ may induce acute or chronic dysfunction of the other. Type 1 CRS reflects
an abrupt worsening of cardiac function leading to acute kidney injury. Type 2
CRS describes chronic abnormalities in cardiac function causing progressive
chronic kidney disease. Type 3 CRS consists in an abrupt worsening of renal
function causing acute cardiac disorder. Type 4 CRS describes a state of chronic
kidney disease contributing to decreased cardiac function, cardiac hypertrophy,
and/or increased risk of adverse cardiovascular events. Type 5 CRS reflects a
systemic condition (eg, sepsis) simultaneously causing both cardiac and renal
dysfunction. Biomarkers can help characterize the subtypes of CRS as well as
suggest the timing of treatment initiation and its likely effectiveness. The
identification of patients and the pathophysiologic mechanisms underlying each
syndrome subtype, including fluid overload or, in general, altered conditions of
fluid status, can help physicians understand clinical derangements, provide the
rationale for management strategies, and allow the design of future clinical
trials with more accurate selection and stratification of the population under
investigation. The cardiorenal syndrome type 4 (Chronic Renocardiac Syndrome) is characterized
by a condition of primary chronic kidney disease (CKD) that leads to an
impairment of the cardiac function, ventricular hypertrophy, diastolic
dysfunction, and/or increased risk of adverse cardiovascular events. Clinically,
it is very difficult to distinguish between CRS type 2 (Chronic Cardiorenal
Syndrome) and CRS type 4 (Chronic Renocardiac Syndrome) because often it is not
clear whether the primary cause of the syndrome depends on the heart or the
kidney. Autosomal domit polycystic kidney disease (ADPKD), a genetic disease
that causes CKD, could be viewed as an ideal prototype of CRS type 4 because it
is certain that the primary cause of cardiorenal syndrome is the kidney disease.
In this paper, we will briefly review the epidemiology of ADPKD, conventional
and novel biomarkers which may be useful in following the disease process, and
prevention and treatment strategies. "Cardio-renal syndromes" (CRS) are disorders of the heart and kidneys whereby
acute or chronic dysfunction in one organ may induce acute or chronic
dysfunction of the other. The current definition has been expanded into five
subtypes whose etymology reflects the primary and secondary pathology, the
time-frame and simultaneous cardiac and renal co-dysfunction secondary to
systemic disease: CRS type I: acute worsening of heart function (AHF-ACS)
leading to kidney injury and/or dysfunction. CRS type II: chronic abnormalities
in heart function (CHF-CHD) leading to kidney injury or dysfunction. CRS type
III: acute worsening of kidney function (AKI) leading to heart injury and/or
dysfunction. CRS type IV: chronic kidney disease (CKD) leading to heart injury,
disease and/or dysfunction. CRS type V: systemic conditions leading to
simultaneous injury and/or dysfunction of heart and kidney. These different
subtypes may have a different pathophysiological mechanism and they may
represent separate entities in terms of prevention and therapy. Cardiorenal syndrome (CRS) clinical types, prevalence, aetiology, and acute
cardiovascular morbidity impact on the outcome of acute kidney function
perturbation were determined. Forty-seven of 101 (46.53%) patients with
perturbed kidney function had CRS. Types 3 and 5 CRS were found in 10 and 37
patients, respectively. Type 3 CRS was due to acute glomerulonephritis (AGN; n =
7), captopril (n = 1), frusemide (n = 1), and hypovolaemia (n = 1).
Malaria-associated haemoglobinuria (n = 20), septicaemia (n = 11), lupus
nephritis (n = 3), tumour lysis syndrome (n = 2), and acute lymphoblastic
leukaemia (n = 1) caused Type 5 CRS. The cumulative mortality in hypertensive
CRS was similar to nonhypertensive CRS (51.4% versus 40.9%; P = .119). Mortality
in CRS and non-CRS was similar (45.7% versus 24.5%; P = .053). Type 5 survived
better than type 3 CRS (66.7% versus 12.5%; P = .001). Risk factors for
mortality were Type 3 CRS (P = .001), AGN-associated CRS (P = .023), dialysis
requiring CRS (P = .008), and heart failure due to causes other than anaemia (P
= .003). All-cause-mortality was 34.2%. Preventive measures aimed at the
preventable CRS aetiologies might be critical to reducing its prevalence. Over the last decade, it has become increasingly clear that the cardiovascular
and renal systems are interdependent. Primary disorders of either system have
been shown to disturb the other system. As a result, a class of cardiorenal
syndrome (CRS) has been identified where in a vicious cycle is established in
which acute/chronic dysfunction of either the kidney or the heart exacerbates
the loss of function in the other organ. The ADQI organization has proposed a
classification derived from a consensus conference held in 2008. CRS is
classified as a disorder of the heart and kidneys whereby acute or chronic
dysfunction in one organ may induce acute or chronic dysfunction in the other.
The general definition has been expanded into five subtypes: CRS type 1 = acute
worsening of heart function (acute heart failure-acute coronary syndrome)
leading to kidney injury and/or dysfunction; CRS type 2 = chronic abnormalities
in heart function (chronic heart failure-chronic heart disease) leading to
kidney injury or dysfunction; CRS type 3 = acute worsening of kidney function
(acute kidney injury) leading to heart injury and/or dysfunction; CRS type 4 =
chronic kidney disease (chronic kidney disease) leading to heart injury, disease
and/or dysfunction; and CRS type 5 = systemic conditions leading to simultaneous
injury and/or dysfunction of heart and kidney. A major problem with previous
terminology was that it did not allow for identification of pathophysiological
interactions occurring in the different types of combined heart/kidney
disorders. The subdivision into different subtypes seems to provide a better
approach to this syndrome. The term cardiorenal syndrome (CRS) describes a broad spectrum of clinical
conditions with four combinations of acute and chronic heart and kidney failure.
Based on the pathophysiological primum movens, the actual classification
recognizes five CRS types: in type I and II CRS, the initiating event is heart
failure (acute or chronic), while it is kidney failure in type III and IV CRS;
type V is linked to systemic diseases. Ultrasound techniques (echocardiography
and ultrasonography of the kidney, inferior vena cava and chest) can be
extremely helpful in establishing a prompt diagnosis and a correct CRS
classification. Basic echocardiography allows evaluation of ventricular
diastolic and systolic functions, investigates pulmonary congestion and
pericardial effusion, and describes volume overload. On the other hand, renal
ultrasound helps clinicians to distinguish between acute and chronic renal
failure, excludes urinary tract dilation or pathological bladder repletion, and
provides crucial information regarding kidney volume or echogenicity. Applying
basic knowledge of echocardiography and renal ultrasound, nephrologists may be
in a better position for patient treatment and management, bearing in mind that
doctors can properly use a stethoscope although not being a cardiologist. The term cardiorenal syndrome (CRS) refers to multiple possible
clinicopathological correlations between heart and kidney failure. The most
recent classification recognizes five types of CRS: types I and II originate
from heart failure (acute and chronic, respectively), type III and IV from
kidney failure (again acute and chronic), while type V originates from a range
of systemic diseases. Echocardiography and renal ultrasound are important means
to arrive at a correct diagnosis. Basic echocardiography (defined by some as
"echocardioscopy") allows the assessment of the left and right ventricles
(diastolic and systolic function), atrial size, pulmonary circulation markers
such as systolic pulmonary arterial pressure (PAPs) and tricuspid annular plane
excursion (TAPSE), pericardial effusions, valve dysfunctions, and volume
repletion. Renal ultrasound is of help in distinguishing between chronic and
acute renal failure (kidney volume, parenchymal thickness, echogenicity) and
excluding obstructive kidney disease. Heart and kidney disease often coexist in the same patient, and observational
studies have shown that cardiac disease can directly contribute to worsening
kidney function and vice versa. Cardiorenal syndrome (CRS) is defined as a
complex pathophysiological disorder of the heart and the kidneys in which acute
or chronic dysfunction in one organ may induce acute or chronic dysfunction in
the other organ. This has been recently classified into five subtypes on the
basis of the primary organ dysfunction (heart or kidney) and on whether the
organ dysfunction is acute or chronic. Of particular interest to the critical
care specialist are CRS type 1 (acute cardiorenal syndrome) and type 3 (acute
renocardiac syndrome). CRS type 1 is characterized by an acute deterioration in
cardiac function that leads to acute kidney injury (AKI); in CRS type 3, AKI
leads to acute cardiac injury and/or dysfunction, such as cardiac ischemic
syndromes, congestive heart failure, or arrhythmia. Both subtypes are
encountered in high-acuity medical units; in particular, CRS type 1 is commonly
seen in the coronary care unit and cardiothoracic intensive care unit. This
paper will provide a concise review of the epidemiology, pathophysiology,
prevention strategies, and selected kidney management aspects for these two
acute CRS subtypes. The cardiorenal syndrome (CRS) indicates how close the relationship is between
heart and kidney during failure of these organs. At present, the classification
of the syndrome includes five types of CRS: types I and II which are strictly
related to initial heart failure (both acute and chronic), types III and IV
which include initial kidney failure, and type V which includes several systemic
diseases. Many pathophysiological pathways have been described illustrating how
heart and kidney disease are involved in clinical conditions. The diagnosis of
CRS is based on both blood tests and ultrasound imaging. Several biomarkers
indicating levels of heart and kidney function have emerged over the last few
decades which can be used to predict kidney failure in patients with acute or
chronic heart disease. Kidney injury biomarkers have also to be tested,
especially those indicating glomerular and tubular damage. Renal ultrasound and
trans-thoracic echocardiography can provide further information on heart and
kidney failure in patients with cardio-renal syndrome at any stage. Cardiorenal syndrome (CRS) includes a broad spectrum of diseases within which
both the heart and kidneys are involved, acutely or chronically. An effective
classification of CRS in 2008 essentially divides CRS in two main groups,
cardiorenal and renocardiac CRS, based on primum movens of disease (cardiac or
renal); both cardiorenal and renocardiac CRS are then divided into acute and
chronic, according to onset of disease. The fifth type of CRS integrates all
cardiorenal involvement induced by systemic disease. This article addresses the
pathophysiology, diagnosis, treatment, and outcomes of the 5 distinct types of
CRS. BACKGROUND: Many patients admitted to a Department of Internal Medicine have
different degrees of heart and kidney dysfunction. Mortality, morbidity and cost
of care greatly increase when cardiac and renal diseases coexist.
METHODS: A retrospective cohort study was conducted on 1,087 patients admitted
from December 2009 to December 2012 to evaluate the prevalence of the
cardiorenal syndrome (CRS) and clinical features.
RESULTS: Out of 1,087 patients discharged from our unit during the study period,
190 (17.5%) were diagnosed as having CRS and classified into five types. CRS was
more common in males (68.9%). CRS type 1 was associated with higher age (79.9 ±
8.9 years) and accounted for 61.5% of all deaths (p < 0.001), representing a
risk factor for mortality (OR 4.23, 95% CI 1.8-10). Congestive heart failure was
significantly different among the five CRS types (p < 0.0001) with a greater
frequency in type 1 patients. Infectious diseases were more frequent in CRS
types 1, 3 and 5 (p < 0.05). Pneumonia presented a statistically higher
frequency in CRS types 1 and 5 compared to other classes (p < 0.01), and
community-acquired infections were statistically more frequent in CRS types 1
and 5 (p < 0.05). The distribution of community-acquired pneumonia was different
among the classes (p < 0.01) with a higher frequency in CRS types 1, 3 and 5.
CONCLUSION: CRS is a condition that is more frequently observed in the clinical
practice. The identification of predisposing trigger factors, such as infectious
diseases, particularly in the elderly, plays a key role in reducing morbidity
and mortality. An early recognition can be useful to optimize therapy, encourage
a multidisciplinary approach and prevent complications. The coexistence of essential hypertension (EH) in type 2 diabetic (T2D) patients
greatly enhances chronic kidney disease.
OBJECTIVES: To assess the acute renal dysfunction in two cohorts of
diabetic-hypertensive subjects. The inaugural pathology for each group is either
T2D or EH.
PATIENTS AND METHODS: The study was undertaken on 506 subjects who were divided
in 5 groups according to age and sex: diabetic, hypertensive, diabetic-
hypertensive (DH and HD) and healthy groups. Patients were phenotyped regarding
their cardiometabolic syndrome (CMS) profile using the NCEP/ATPIII criteria and
cardiorenal syndrome (CRS) according to the International kidney foundation.
Hypertension was defined as systolic (SBP) and diastolic (DBP) blood pressure ≥
140/90 mmHg, respectively. Insulin resistance (IR) was assessed by Homa-IR
model. Glomerular filtration rate (GFR) by creatinine clearance. CMS and CRS
parameters were determined on Cobas®. The SBP and DBP measurements by electronic
blood pressure using Omron 705 CP® type.
RESULTS: IR was found in all diabetics and hypertensive patients. Dyslipidemia
are correlated to % body fat mass accretion in all groups. In DH group, the
renal disorder is confirmed by decreased GFR (30%) and increased
microalbuminuria (> 30 mg/24h); associated with increased NT-pro BNP and plasma
aldosterone depletion.
CONCLUSION: Several biomarkers are necessary to detection kidney disease and
renal failure prevention in diabetic patients to hypertensive state. The renal
dysfunction was significantly related to T2D-EH disease. Chronic kidney disease (CKD) increases the risk of all-cause mortality and
cardiovascular disease as well as progression to end stage kidney failure. The
relationship of glomerular filtration rate (GFR) and albuminuria with clinical
outcomes in the general population are revealed. This allows to present levels
of GFR and microalbuminuria (MA), which increases the risk of mortality. Renal
dysfunction, which revealed by the level of GFR and creatinine, can have
definite role in hemodynamic changes and heart failure progression. For
mentioning the interaction of cardiovascular and renal diseases the cardiorenal
syndrome (CRS) term was introduced, with its classification on 5 types,
according to the presence of acute/chronic heart failure and primary/secondary
origination of heart and kidney injury. We study interrelations between
echocardiographic data of left ventricular remodeling, MA level and degree of
renal dysfunction in 115 patients with CRS. MA was measured with diagnostic
strips, contractile function of left ventricle (LV) - by echocardiography and
GFR was assessed by Cocroft-Gault method. The association between MA with
decreased GFR and elevated creatinine levels and its connection with increased
LV myocardial mass and preclinical disturbances of LV systolic function was
revealed. We determined direct correlation between MA and myocardial mass index
and indirect - between ejection fraction of LV and MA. Obtained data allow to
mention the level of MA (25,4±5,8 ng/ml) in which there is more probability of
LV contractile functional changes, which will allow early prediction and
prevention of CRS progression and pathogenetically approved pharmacotherapy
organization in this category patients. Heart and kidney are closely interacting organs which function interdependently.
Organ crosstalk between these two organs is based on humoral regulation and by
inflammatory mediators, which are similar to those dominating systemic
inflammation syndrome. The close interaction between heart and kidney results in
organ dysfunction following both chronic and acute functional impairment of the
respective counterpart. These changes are summarized under the term cardiorenal
syndrome (CRS) which is subdivided into 5 types. In the setting of emergency
medicine and intensive care units, CRS types 1 and 3 are the most common. CRS
type 1 is characterized by acute kidney injury (AKI) developing as a consequence
of acute heart failure. CRS type 3 is represented by acute cardiac failure
following AKI, often occurring as a consequence of nephrotoxins. Diagnosis of
CRS should preferably be made on basis of the Kidney Disease: Improving Global
Outcomes (KDIGO) criteria for the diagnosis and staging of AKI. The cardiac
diagnostic workup should include echocardiography, electrocardiogram (ECG),
cardiac enzymes, and brain natriuretic peptide (BNP). The therapeutic approach
in CRS is primarily aimed at treating the causative organ dysfunction. In case
of CRS type 3 this means ensuring adequate kidney perfusion, cautious fluid
management, and avoiding additional nephrotoxins. In case of diuretic resistant
fluid overload, early initiation of extracorporeal fluid removal, preferably by
renal replacement therapy, should be considered. |
What is a miR? | The discovery of microRNAs (miRNAs) has opened an entire new avenue for drug development. These short (15-22 nucleotides) noncoding RNAs, which function in RNA silencing and posttranscriptional regulation of gene expression, have been shown to critically affect numerous pathways in both development and disease progression. | Bladder cancer (BC) is generally divided into non-muscle-invasive BC (NMIBC) and
muscle-invasive BC (MIBC). The standard treatment protocol for MIBC patients is
radical cystectomy preceded by neoadjuvant chemotherapy (NAC). About one-half of
the MIBC patients show a priori resistance to chemotherapy, and are therefore
exposed to the risks of disease progression and toxicity from ineffective NAC.
The discovery of microRNA (miRNA) regulation in tumorigenesis has provided new
directions for the development of a new type of BC biomarkers. In this review,
we describe the emerging miRNAs as BC biomarkers for different purposes,
including diagnosis, prognosis and therapeutic response. miRNA expression
profile changes with alteration of the tissue phenotype. This phenomenon is
utilized to predict tumor diagnosis, cancer subclass, disease stage, prognosis
and therapeutic response. We classified the miRNAs which are involved in bladder
cancer according to maligt potential, chemoresistance, discrimination between
normal to cancerous and clinical outcome. Focusing on the major obstacle
regarding MIBC patient's NAC response, we summarized the miRNAs that are
deregulated and have the potential to identify the patients resistant to NAC,
such as miR-34, miR-100, miR-146b and miR-9 and miR-193a-3p. In conclusion,
miRNAs expression profile of bladder cancer patient is a promising tool that can
serve as biomarker for different aims. Based on this profile we propose upfront
radical cystectomy instead of standard NAC to those MIBC patients who are at
higher risk for chemoresistance and poor response. Liver fibrosis occurs during chronic injury and represents, in large part, an
exaggerated matrigenic output by hepatic stellate cells (HSCs) which become
activated as a result of injury-induced signaling pathways in parenchymal and
inflammatory cells (hepatocytes, macrophages, etc.). The molecular components in
these pathways (e.g., CCN proteins) are modulated by transcription factors as
well as by factors such as microRNAs (miRs) that act posttranscriptionally. MiRs
are small (~23 nt) noncoding RNAs that regulate gene expression by specifically
interacting with the 3' untranslated region (UTR) of target gene mRNA to repress
translation or enhance mRNA cleavage. As well as acting in their cells of
production, miRs (and other cellular constituents such as mRNAs and proteins)
can be liberated from their cells of origin in ovesicular membrane exosomes,
which traverse the intercellular spaces, and can be delivered to neighboring
cells into which they release their molecular payload, causing alterations in
gene expression in the target cells. Here we summarize some of the experimental
approaches for studying miR action and exosomal trafficking between hepatic
cells. Insights into the mechanisms involved will yield new information about
how hepatic fibrosis is regulated and, further, may identify new points of
therapeutic intervention. Diabetes is generally associated with vasculopathy, which contains both
microvascular and macrovascular complications, associated with high morbidity
and mortality. Currently, despite interventional therapy, the overall prognosis
for patients with diabetic vasculopathy remains unsatisfactory. Angiogenesis and
vascular injury and repair are associated with a variety of cells. However, the
molecular mechanisms of the cells that are involved in pathogenesis of diabetic
vasculopathy remain largely unknown. As novel molecules, microRNAs (miRs) take
part in regulating protein-coding gene expression at the post-transcriptional
level, and contribute to the pathogenesis of various types of chronic metabolism
disease, especially diabetic vasculopathy. This allows miRs to have a direct
function in regulation of various cellular events. Additionally, circulating
miRs have been proposed as biomarkers for a wide range of cardiovascular
diseases. This review elucidates miR-mediated regulatory mechanisms in diabetic
vasculopathy. Furthermore, we discuss the current understanding of miRs in
diabetic vasculopathy. Finally, we summarize the development of novel diagnostic
and therapeutic strategies for diabetic vasculopathy related to miRs. The discovery of microRNAs (miRNAs) has opened an entire new avenue for drug
development. These short (15-22 nucleotides) noncoding RNAs, which function in
RNA silencing and posttranscriptional regulation of gene expression, have been
shown to critically affect numerous pathways in both development and disease
progression. Current miRNA drug development focuses on either reintroducing the
miRNA into cells through the use of a miRNA mimic or inhibiting its function via
use of a synthetic antagomir. Although these methods have shown some success as
therapeutics, they face challenges particularly with regard to cellular uptake
and for use as systemic reagents. We recently presented a novel mechanism of
inhibiting miR-544 by directed inhibition of miRNA biogenesis. We found that
inhibition of DICER processing of miR-544 through the use of a small molecule
abolished miR-544 function in regulating adaptation of breast cancer cells to
hypoxic stress. Herein, we describe a protocol that utilizes bioinformatics to
first identify lead small molecules that bind to DICER cleavage sites in
pre-miRNAs and then employ an efficient, high-throughput fluorescent-based
screening system to determine the inhibitory potential of the lead compounds and
their derivatives. |
Do circRNAs remain untranslated? | The resulting circRNA can be translated to generate functional proteins. | While the human transcriptome contains a large number of circular RNAs
(circRNAs), the functions of most circRNAs remain unclear. Sequence annotation
suggests that most circRNAs are generated from splicing in reversed orders
across exons. However, the mechanisms of this backsplicing are largely unknown.
Here we constructed a single exon minigene containing split GFP, and found that
the pre-mRNA indeed produces circRNA through efficient backsplicing in human and
Drosophila cells. The backsplicing is enhanced by complementary introns that
form double-stranded RNA structure to bring splice sites in proximity, but such
structure is not required. Moreover, backsplicing is regulated by general
splicing factors and cis-elements, but with regulatory rules distinct from
canonical splicing. The resulting circRNA can be translated to generate
functional proteins. Unlike linear mRNA, poly-adenosine or poly-thymidine in 3'
UTR can inhibit circular mRNA translation. This study revealed that backsplicing
can occur efficiently in diverse eukaryotes to generate circular mRNAs. The human genome is under constant invasion by retrotransposable elements. The
most successful of these are the Alu elements; with a copy number of over a
million, they occupy about 10 % of the entire genome. Interestingly, the vast
majority of these Alu insertions are located in gene-rich regions, and one-third
of all human genes contains an Alu insertion. Alu sequences are often embedded
in gene sequence encoding pre-mRNAs and mature mRNAs, usually as part of their
intron or UTRs. Once transcribed, they can regulate gene expression as well as
increase the number of RNA isoforms expressed in a tissue or a species. They
also regulate the function of other RNAs, like microRNAs, circular RNAs, and
potentially long non-coding RNAs. Mechanistically, Alu elements exert their
effects by influencing diverse processes, such as RNA editing, exonization, and
RNA processing. In so doing, they have undoubtedly had a profound effect on
human evolution. Circular RNAs (circRNAs) are involved in the development of various diseases,
but there is little knowledge of circRNAs in osteoarthritis (OA). The aim of
study was to identify circRNA expression in articular cartilage and to explore
the function of chondrocyte extracellular matrix (ECM)-related circRNAs
(circRNA-CER) in cartilage. To identify circRNAs that are specifically expressed
in cartilage, we compared the expression of circRNAs in OA cartilage with that
in normal cartilage. Bioinformatics was employed to predict the interaction of
circRNAs and mRNAs in cartilage. Loss-of-function and rescue experiments for
circRNA-CER were performed in vitro. A total of 71 circRNAs were differentially
expressed in OA and normal cartilage. CircRNA-CER expression increased with
interleukin-1 and tumor necrosis factor levels in chondrocytes. Silencing of
circRNA-CER using small interfering RNA suppressed MMP13 expression and
increased ECM formation. CircRNA-CER could compete for miR-136 with MMP13. Our
results demonstrated that circRNA-CER regulated MMP13 expression by functioning
as a competing endogenous RNA (ceRNA) and participated in the process of
chondrocyte ECM degradation. We propose that circRNA-CER could be used as a
potential target in OA therapy. Recent studies have revealed that, in addition to hormones and other protein
factors, noncoding RNA molecules play an important regulatory role in milk
protein synthesis. Circular RNAs (circRNAs) are universally expressed noncoding
RNA species that have been proposed recently to regulate the expression of their
parental genes. In the present study, the deep RNA-sequencing technique known as
RNA-seq was used to compare expression profiles of circRNAs from 2 pooled RNA
samples from cow mammary gland on d 90 and 250 postpartum and to identify the
key circRNAs involved in lactation. A total of 4,804 and 4,048 circRNAs were
identified in the cow mammary gland on d 90 and 250 postpartum, respectively, of
which only 2,231 circRNAs were co-expressed at both lactation stages, suggesting
high stage specificity in the circRNAs. The enrichment of some Gene Ontology
terms for the circRNA parental genes differed between lactation stages. Among
the top 10 enriched Gene Ontology terms, vesicle, endoplasmic reticulum, and
mitochondrial lumen were more common on lactation d 90. All 4 casein-coding
genes (CSN1S1, CSN1S2, CSN2, and CSN3) produced circRNAs in the cattle mammary
gland. In total, 80 circRNAs were identified from these 4 genes; circRNAs from
CSN1S1 had very high abundance, and 3 of them accounted for 36% of all the
circRNAs expressed in the mammary gland on lactation d 90. Three circRNAs from
CSN1S1, 1 circRNA from CSN1S2, and 1 circRNA from CSN2 were all more highly
expressed on lactation d 90 than on lactation d 250, as confirmed by
quantitative PCR. These circRNAs had several target sites for the microRNA
miR-2284 family and were predicted to target CSN1S1 and CSN2 mRNA, suggesting
their potential involvement in regulating expression of the casein genes. AIMS: This study aimed to identify the different expression of circular RNAs
(circRNAs) in the placental tissues of pregt women with preeclampsia (PE) and
to provide a new avenue of research regarding the pathological mechanisms of PE.
METHODS: In this study, we collected 40 placental tissues from PE patients and
35 placental tissues from gestational age-matched patients who gave premature
birth. Arraystar circRNA Microarray Technology (KANGCHEN, Shanghai, China) was
used to analyze the differential expression of circRNAs. According to the basic
content of circRNAs in the two groups and their fold changes and due to the
practicability of the designed divergent primers of each candidate circRNA, we
selected three up-regulated circRNAs, hsa_circRNA_100782, hsa_circRNA_102682 and
hsa_circRNA_104820, to validate the data. Real-time quantitative reverse
transcriptase-polymerase chain reaction (qRT-PCR) was utilized to estimate the
Ct values in both groups. We further evaluated the differences with a paired
t-test and a receiver operating characteristic (ROC) curve.
RESULTS: Many circRNAs were found to be differentially expressed in PE placental
tissues versus their controls; of these, 143 circRNAs were up-regulated and 158
were down-regulated. The expression levels of hsa_circRNA_100782 (p < 0.05),
hsa_circRNA_102682 (p < 0.05), and hsa_circRNA_104820 (p < 0.0001) were
validated as significantly up-regulated in the experimental group compared with
the controls. Finally, we performed a literature comparison to forecast the
possible mechanisms of circRNA function during PE.
CONCLUSION: circRNA expression significantly differed in placental PE tissues
compared with controls. According to the circRNA microarray results and the
existing papers, circRNAs may contribute to the pathogenesis of PE by acting as
miRNA sponges; this possibility requires additional investigation in future
studies. The pathogenesis of nonalcoholic steatohepatitis (NASH) is still unclear, where
involvement of circRNA is considered for its active role as "miRNA sponge".
Therefore, we aimed to investigate the circRNA expression pattern in NASH and
further construct the circRNA-miRNA-mRNA network for in-depth mechanism
exploration. Briefly, NASH mice model was established by Methionine and choline
deficiency (MCD) diet feeding. Liver circRNA and mRNA profile was initially
screened by microarray and ensuing qRT-PCR verification was carried out. The
overlapped predicted miRNAs as downstream targets of circRNAs and upstream
regulators of mRNAs were verified by qRT-PCR and final circRNA-miRNA-mRNA
network was constructed. Gene Ontology (GO) and KEGG pathway analysis were
further applied to enrich the huge mRNA microarray data. To sum up, there were
69 up and 63 down regulated circRNAs as well as 2760 up and 2465 down regulated
mRNAs in NASH group, comparing with control group. Randomly selected 13 of 14
mRNAs and 2 of 8 circRNAs were successfully verified by qRT-PCR. Through
predicted overlapped miRNA verification, four circRNA-miRNA-mRNA pathways were
constructed, including circRNA_002581-miR-122-Slc1a5, circRNA_002581-
miR-122-Plp2, circRNA_002581-miR-122-Cpeb1 and circRNA_007585-miR-326- UCP2. GO
and KEGG pathway analysis also enriched specific mRNAs. Therefore, circRNA
profile may serve as candidate for NASH diagnosis and circRNA-miRNA -mRNA
pathway may provide novel mechanism for NASH. Cell states in hematopoiesis are controlled by master regulators and by complex
circuits of a growing family of RNA species impacting cell phenotype maintece
and plasticity. Circular RNAs (circRNAs) are rapidly gaining the status of
particularly stable transcriptome members with distinctive qualities. RNA-seq
identified thousands of circRNAs with developmental stage- and tissue-specific
expression corroborating earlier suggestions that circular isoforms are a
natural feature of the cell expression program. CircRNAs are abundantly
expressed also in the hematopoietic compartment. There are a number of studies
on circRNAs in blood cells, a specific overview is however lacking. In this
review we first present current insight in circRNA biogenesis discussing the
relevance for hematopoiesis of the highly interleaved processes of splicing and
circRNA biogenesis. Regarding molecular functions circRNAs modulate host gene
expression, but also compete for binding of microRNAs, RNA-binding proteins or
translation initiation and participate in regulatory circuits. We examine
circRNA expression in the hematopoietic compartment and in hematologic
maligcies and review the recent breakthrough study that identified pathogenic
circRNAs derived from leukemia fusion genes. CircRNA high and regulated
expression in blood cell types indicate that further studies are warranted to
inform the position of these regulators in normal and maligt hematopoiesis. |
What is the biological function of the SRY circular RNA (circRNA)? | We suggest that the circles arise from normal splicing processes as a consequence of the unusual genomic structure surrounding the Sry locus in the mouse. While this result does not prove a direct interaction between the two genes, it defines the critical period during which Sry must act to initiate Sertoli cell differentiation. We also attempted to make clear whether the equine SRY gene transcript is expressed in the adult testis, and whether the type of transcript is expressed as linear or circular RNA. We further show that the testis-specific circRNA, sex-determining region Y (Sry), serves as a miR-138 sponge, suggesting that miRNA sponge effects achieved by circRNA formation are a general phenomenon Recent studies have mainly been devoted to the function of the circular RNA sponge for miR-7 (ciRS-7) and sex-determining region Y (SRY) by targeting microRNA-7 (miR-7) and microRNA-138 (miR-138), respectively However, the characteristics and the critical role of circRNA in co-/post-transcriptional regulation were not well recognized until the "microRNA sponge" function of circRNA is discovered | Sry is expressed at higher levels in the adult testis, where no function has
been determined, than in the genital ridge, its critical site of action. cDNA
and 5' RACE clones isolated from testis or from Sry-transfected cell lines have
an unusual structure, with 3' sequences located in a 5' position. RNAase
protection assays and reverse transcription polymerase chain reactions confirmed
that these unusual RNA molecules represent the most abundant transcript in
testis. Furthermore, oligonucleotide hybridization and RNAase H digestion proved
that these Sry RNA molecules are circular. Similar transcripts were detected in
the testes of mice with Mus musculus musculus, Mus musculus domesticus, and Mus
spretus Sry genes. The circular RNA is found in the cytoplasm but is not
substantially bound to polysomes. We suggest that the circles arise from normal
splicing processes as a consequence of the unusual genomic structure surrounding
the Sry locus in the mouse. Correct ligation of exons in pre-mRNA splicing requires splice site
juxtaposition (splice site pairing), usually involving a 5' splice site and a
downstream 3' splice site. Splicing of a 5' splice site to an upstream 3' splice
site, however, is predicted to result in a circular RNA. This mode of splice
site pairing across the axon has been hypothesized to account for rare RNAs
containing scrambled exons (Nigro JM et al., 1991, Celt 64:607-613; Cocquerelle
C et al., 1992, EMBO J 11:1 095-1098). Additionally, this mode of splice site
pairing has been postulated to explain the formation of SRY circular transcripts
in mouse testis (Capel B et al., 1993, Celt 73:1019- 1030). Here we show that
splice site pairing across the exon can result in exon circularization in vitro.
These results indicate that spliceosome-mediated axon circularization indeed can
account for the formation of scrambled exons and circular RNAs. Exon
circularization efficiency decreased dramatically as the length of the exon was
increased from 95 nt to 274 nt. Circularization of this longer exon was
restored, however, when intronic complementary sequences were included in the
RNA substrate. These complementary sequences could form a stem that served to
bring the splice sites into proximity and thereby promote splice site pairing.
Therefore, the splicing of this structured RNA recapitulated SRY-like exon
circularization in vitro. Employing a combination of reverse transcription-polymerase chain reaction
(RT-PCR) and rapid amplification of cDNA ends (RACE) techniques, the complete
coding sequence of cDNA for the equine SRY gene was determined. We also
attempted to make clear whether the equine SRY gene transcript is expressed in
the adult testis, and whether the type of transcript is expressed as linear or
circular RNA. As a result, in total a 1420 bp cDNA sequence was determined.
Accomplishment of 3' RACE infers that equine SRY gene was expressed as a linear
RNA transcript in testicular tissue just after puberty, in contrast to the
situation in mice. Recently, the sex determining region Y ( Sry) and the cerebellar
degeneration-related protein 1 ( CDR1as) RNA transcripts have been described to
function as a new class of post-transcriptional regulatory RNAs that behave as
circular endogenous RNA sponges for the micro RNAs (miRNAs) miR-138 and miR-7,
respectively. A special feature of the Sry gene is its ability to generate
linear and circular transcripts, both transcribed in the sense orientation. Here
we remark that both sense (e.g. Sry RNA) and antisense (e.g. CDR1as) transcripts
could circularize and behave as miRNAs sponges, and importantly, that also
protein-coding segments of mRNAs could also assume this role. Thus, it is
reasonable to think that the linear Sry sense transcript could additionally act
as a miRNA sponge, or as an endogenous competing RNA for miR-138. Circular RNAs (circRNAs) are long, non-coding RNAs that result from the
non-canonical splicing of linear pre-mRNAs. However, the characteristics and the
critical role of circRNA in co-/post-transcriptional regulation were not well
recognized until the "microRNA sponge" function of circRNA is discovered. Recent
studies have mainly been devoted to the function of the circular RNA sponge for
miR-7 (ciRS-7) and sex-determining region Y (SRY) by targeting microRNA-7
(miR-7) and microRNA-138 (miR-138), respectively. In this review, we illustrate
the specific role of circRNAs in a wide variety of cancers and in regulating the
biological behavior of cancers via miR-7 or miR-138 regulation. Furthermore,
circRNA, together with its gene silencing ability, also shows its potential in
RNA interference (RNAi) therapy by binding to target RNAs, which provides a
novel perspective in cancer treatment. Thus, this review concerns the
biogenesis, biological function, oncogenesis, progression and possible therapies
for cancer involving circRNAs. |
What is Uhl's anomaly? | uhl's anomaly is an extremely rare cardiac defect characterized by absence of the myocardium of the right ventricle. | Uhl's anomaly was first reported by Uhl in 1952 and is characterized by
congenital partial or complete absence of right ventricular myocardium. It is a
very rare anomaly with unknown aetiology. Associations with other congenital
heart diseases, familial occurrency, sudden death and arrhythmia with Uhl's
anomaly have been reported. Pathologic findings vary with the patient's age and
severity of the right ventricular disorder. In infancy, it may occur with severe
right-sided heart failure as well as asymptomatic cardiomegaly. Despite its
rarity, Uhl's anomaly may be considered in patients with right ventricular
failure due to dilated cardiomyopathy of the right ventricle. We report the case
of six-year-old boy presenting with striking ascites due to severe right heart
failure of Uhl's anomaly. Uhl's anomaly is an evolutive disease leading to terminal right ventricular
failure. The most difficult differential diagnosis at presentation is the
Ebstein disease. We describe the evolution of a foetus with Uhl's anomaly from
21 to 30 weeks of gestation, with progressive reduction in the right ventricular
anterior myocardium suggestive of apoptosis, leading to foetal demise. Uhl anomaly is a rare form of congenital hypoplasia of the right ventricular
myocardium. Here, we report, a rare finding in fetal cardiac ultrasound in a
33-year-old woman who presented at 20 weeks' of gestation. A diagnosis of Uhl
anomaly was made. An autopsy was performed at 23weeks gestation after obtaining
permission for medicolegal termination of pregcy. Histopathological
examination confirmed the diagnosis. Diagnosing Uhl anomaly in fetal life is
essential since mortality and survival mainly depend on the severity of right
ventricle dysfunction related to, the either partial or complete absence of the
myocardium. Hence, surviving cases need to be followed up carefully and
counselled accordingly. |
Is autophagy the process where bacteria ingest viral particles? | Autophagy, a cellular degradation process | Autophagy (macroautophagy) is a dynamic process for degradation of cytosolic
components. Autophagy has intracellular anti-viral and anti-bacterial functions,
and plays a role in the initiation of innate and adaptive immune system
responses to viral and bacterial infections. Some viruses encode virulence
factors for blocking autophagy, whereas others utilize some autophagy components
for their intracellular growth or cellular budding. The "core" autophagy-related
(Atg) complexes in mammals are ULK1 protein kinase, Atg9-WIPI-1 and
Vps34-beclin1 class III PI3-kinase complexes, and the Atg12 and LC3 conjugation
systems. In addition, PI(3)-binding proteins, PI3-phosphatases, and Rab proteins
contribute to autophagy. The autophagy process consists of continuous dynamic
membrane formation and fusion. In this review, the relationships between these
Atg complexes and each process are described. Finally, the critical points for
monitoring autophagy, including the use of GFP-LC3 and GFP-Atg5, are discussed. Japanese encephalitis virus (JEV), an enveloped Flavivirus with a positive-sense
RNA genome, causes acute encephalitis with high mortality in humans. We used a
virulent (RP-9) and an attenuated (RP-2ms) JEV strain to assess the role of
autophagy in JEV infection. By monitoring the levels of lipidated LC3, we found
that autophagy was induced in human NT-2 cells infected with RP-2ms, especially
at the late stage, and to a lesser extent with RP-9. The induction of autophagy
by rapamycin increased viral production, whereas the inhibition of autophagy by
3-methyladenine reduced viral yields for both RP-9 and RP-2ms. The viral
replication of RP-9 and RP-2ms was also reduced in cells with downregulated ATG5
or Beclin 1 expression, suggesting a proviral role of autophagy in JEV
replication. To determine the step of JEV life cycle affected by autophagy, we
used an mCherry-LC3 fusion protein as the autophagosome marker. Little of no
colocalization of LC3 puncta with dsRNA was noted, whereas the input JEV
particles were targeted to autophagosomes stained positive for early endosome
marker. Overall, we show for the first time that the cellular autophagy process
is involved in JEV infection and the inoculated viral particles traffic to
autophagosomes for subsequent steps of viral infection. Autophagy, an intracellular degradation process highly conserved from yeast to
humans, is viewed as an important defence mechanism to clear intracellular
bacteria. However, recent work has shown that autophagy may have different roles
during different bacterial infections that restrict bacterial replication
(antibacterial autophagy), act in cell autonomous signalling (non-bacterial
autophagy) or support bacterial replication (pro-bacterial autophagy). This
review will focus on newfound interactions of autophagy and pathogenic bacteria,
highlighting that, in addition to delivering bacteria to the lysosome, autophagy
responding to bacterial invasion may have a much broader role in mediating
disease outcome. Autophagy is a lysosome-mediated catabolic process involving the degradation of
intracellular contents (e.g., proteins and organelles) as well as invading
microbes (e.g., parasites, bacteria and viruses). Multiple forms of cellular
stress can stimulate this pathway, including nutritional imbalances, oxygen
deprivation, immunological response, genetic defects, chromosomal anomalies and
cytotoxic stress. Damage-associated molecular pattern molecules (DAMPs) are
released by stressed cells undergoing autophagy or injury, and act as endogenous
danger signals to regulate the subsequent inflammatory and immune response. A
complex relationship exists between DAMPs and autophagy in cellular adaption to
injury and unscheduled cell death. Since both autophagy and DAMPs are important
for pathogenesis of human disease, it is crucial to understand how they
interplay to sustain homeostasis in stressful or dangerous environments. Autophagy and the effects of its inhibition or induction were investigated
during the entire infectious cycle of varicella-zoster virus (VZV), a human
herpesvirus. As a baseline, we first enumerated the number of autophagosomes per
cell after VZV infection compared with the number after induction of autophagy
following serum starvation or treatment with tunicamycin or trehalose. Punctum
induction by VZV was similar in degree to punctum induction by trehalose in
uninfected cells. Treatment of infected cells with the autophagy inhibitor
3-methyladenine (3-MA) markedly reduced the viral titer, as determined by assays
measuring both cell-free virus and infectious foci (P < 0.0001). We next
examined a virion-enriched band purified by density gradient sedimentation and
observed that treatment with 3-MA decreased the amount of VZV gE, while
treatment with trehalose increased the amount of gE in the same band. Because
VZV gE is the most abundant glycoprotein, we selected gE as a representative
viral glycoprotein. To further investigate the role of autophagy in VZV
glycoprotein biosynthesis as well as confirm the results obtained with 3-MA
inhibition, we transfected cells with ATG5 small interfering RNA to block
autophagosome formation. VZV-induced syncytium formation was markedly reduced by
ATG5 knockdown (P < 0.0001). Further, we found that both expression and glycan
processing of VZV gE were decreased after ATG5 knockdown, while expression of
the nonglycosylated IE62 tegument protein was unchanged. Taken together, our
cumulative results not only documented abundant autophagy within VZV-infected
cells throughout the infectious cycle but also demonstrated that VZV-induced
autophagy facilitated VZV glycoprotein biosynthesis and processing. Autophagy is a cellular process that targets proteins, lipids and organelles to
lysosomes for degradation, but it has also been shown to combat infection with
various pathogenic bacteria. In turn, bacteria have developed diverse strategies
to avoid autophagy by interfering with autophagy signalling or the autophagy
machinery and, in some cases, they even exploit autophagy for their growth. In
this Review, we discuss canonical and non-canonical autophagy pathways and our
current knowledge of antibacterial autophagy, with a focus on the interplay
between bacterial factors and autophagy components. Autophagy, a programmed process in which cell contents are delivered to
lysosomes for degradation, appears to have both tumor-suppressive and
tumor-promoting functions; both stimulation and inhibition of autophagy have
been reported to induce cancer cell death, and particular genes and proteins
have been associated both positively and negatively with autophagy. To provide a
basis for incisive analysis of those complexities and ambiguities and to guide
development of new autophagy-targeted treatments for cancer, we have compiled a
comprehensive, curated inventory of autophagy modulators by integrating
information from published siRNA screens, multiple pathway analysis algorithms,
and extensive, manually curated text-mining of the literature. The resulting
inventory includes 739 proteins and 385 chemicals (including drugs, small
molecules, and metabolites). Because autophagy is still at an early stage of
investigation, we provide extensive analysis of our sources of information and
their complex relationships with each other. We conclude with a discussion of
novel strategies that could potentially be used to target autophagy for cancer
therapy. Autophagy is a highly conserved process by which cells can recycle organelles
and proteins by degrading them in the lysosomes. Although autophagy is
considered a dynamic system responsible for cellular renovation and homeostasis
under physiological conditions, it is increasingly clear that autophagy is
directly relevant to clinical disease. During disease progression, autophagy not
only serves as a cellular protective mechanism but also can represent a harmful
event under certain conditions. In addition, although autophagy can act as a
nonselective bulk degradation process, recent research shows that autophagy can
selectively degrade specific proteins, organelles, and invading bacteria, in
processes termed "selective autophagy." Selective autophagy has drawn the
attention of researchers because of its potential importance in clinical
diseases. In this article, we outline the most recent studies implicating
autophagy and selective autophagy in human lung diseases, including chronic
obstructive pulmonary disease, pulmonary hypertension, idiopathic pulmonary
fibrosis, and sepsis. We also discuss the relationship between autophagy and
other molecular mechanisms related to disease progression, including programmed
necrosis (necroptosis) and the inflammasome, an inflammatory signaling platform
that regulates the secretion of IL-1β and IL-18. Finally, we examine the dual
nature of autophagy and selective autophagy in the lung, which have both
protective and injurious effects for human lung disease. Oncogene-induced senescence (OIS) is a highly dynamic process, involving several
different effector mechanisms, the multitude and combination of which likely
determines the quality of the phenotype (Pérez-Mancera et al., Nat Rev Cancer
14:547-558, 2014). Autophagy, a cellular degradation process, has been proposed
to be one of these senescence effectors, although its functional relevance seems
highly context dependent (Hoare et al., Semin Cancer Biol 21:397-404, 2011). A
number of methods for monitoring autophagy are available, and several excellent
protocols have been published in this journal (Klionsky et al., Autophagy
8:445-544, 2012; Tooze et al., Methods Mol Biol 1270:155-165, 2015; Tabata et
al., Methods Mol Biol 931:449-466, 2013; Young and Tooze, Methods Mol Biol
445:147-157, 2008). The same principles apply to models of OIS in culture. Thus,
in this chapter, we describe how to generate OIS cells using human diploid
fibroblasts (HDFs), the best-characterized cell model of OIS, and how to detect
autophagy, particularly focusing on immunofluorescence methods. Autophagy, a form of lysosomal degradation capable of eliminating dysfunctional
proteins and organelles, is a cellular process associated with homeostasis.
Autophagy functions in cell survival by breaking down proteins and organelles
and recycling them to meet metabolic demands. However, aberrant up regulation of
autophagy can function as an alternative to apoptosis. The duality of autophagy,
and its regulation over cell survival/death, intimately links it with human
disease. Non-coding RNAs regulate mRNA levels and elicit diverse effects on
mammalian protein expression. The most studied non-coding RNAs to-date are
microRNAs (miRNA). MicroRNAs function in post-transcriptional regulation,
causing profound changes in protein levels, and affect many biological processes
and diseases. The role and regulation of autophagy, whether it is beneficial or
harmful, is a controversial topic in cardiovascular disease. A number of recent
studies have identified miRNAs that target autophagy-related proteins and
influence the development, progression, or treatment of cardiovascular disease.
Understanding the mechanisms by which these miRNAs work can provide promising
insight and potential progress towards the development of therapeutic treatments
in cardiovascular disease. |
Can aspirin be used in cancer prevention? | Long-term aspirin use was associated with a modest but significantly reduced risk for overall cancer, especially gastrointestinal tract tumors. Regular aspirin use may prevent a substantial proportion of colorectal cancers and complement the benefits of screening. | BACKGROUND: Evidence for an association between aspirin or other nonsteroidal
antiinflammatory drug (NSAID) use and basal cell carcinoma (BCC) has been
inconsistent.
OBJECTIVE: We conducted a systematic review and metaanalysis to assess the
effect of oral NSAIDs on BCC.
METHODS: PubMed, Web of Science, and Embase databases were searched up to
December 3, 2014. A random effects model metaanalysis was used to calculate
summary estimates of the effects of aspirin, nonaspirin NSAIDs, or any (aspirin
or nonaspirin) NSAID use in patients with BCC.
RESULTS: The summary estimates from 11 studies (1 randomized controlled trial, 5
cohort studies, and 5 case control studies) found a 10% risk reduction of BCC
among those using any NSAID (relative risk [RR], 0.90 [95% confidence interval
{CI}, 0.84-0.97]). A similar but not statistically significant inverse
association was observed for nonaspirin NSAIDs (RR, 0.93 [95% CI, 0.86-1.02]),
while aspirin use was more weakly associated (RR, 0.95 [95% CI, 0.91-1.00]). The
strongest inverse associations were noted among those with either a history of
skin cancers or a high prevalence of actinic keratoses.
LIMITATIONS: Dose-effect estimates could not be calculated because the available
data were too heterogeneous to pool.
CONCLUSION: The intake of NSAIDs may help prevent BCC, particularly in high-risk
populations. A large randomized controlled trial is required to confirm these
findings. PURPOSE: Based on suggestive findings from a recent study of high-risk Japanese
patients, we sought to determine whether the risk of colorectal polyps
associated with smoking may be modified by daily use of aspirin in an analysis
of a large US screening population.
METHODS: This is a cross-sectional study of 2,918 consecutive colonoscopy
patients at a university hospital over a 30-month period. Data were abstracted
from electronic medical records. Multivariate models of polyp counts were used
to examine the competing risks of smoking and aspirin use. Models were further
stratified by polyp location (proximal vs. distal) and pathologic subtype
(dysplastic vs. serrated).
RESULTS: Incidental rate of polyps was higher among active smokers [incidence
rate ratio (IRR) 1.72; 95 % confidence interval (CI) 1.46-2.02] and lower among
daily aspirin users (IRR 0.73; 95 % CI 0.61-0.86) compared to those who used
neither. Smoking interacts significantly with aspirin use resulting in loss of
aspirin protection (IRR 1.69; 95 % CI 1.28-2.24). Stratified analyses
demonstrate that aspirin specifically reduces the risk of traditional dysplastic
adenomas (IRR 0.72; 95 % CI 0.61-0.86) not serrated/hyperplastic polyps (IRR
0.92; 95 % CI 0.72-1.17) and that the modification of aspirin protection by
smoking is primarily observed within the distal colorectum (p < 0.03).
CONCLUSIONS: We report for the first time, in a typical risk US clinical
population, a lack of protective association of aspirin for polyps among active
smokers. Future prospective studies are recommended to confirm this mitigating
effect in order to improve the precision of the growing evidence base about the
chemopreventive benefit of aspirin in colorectal cancer. A Best Evidence Topic was undertaken to systematically review the evidence
regarding the use of NSAIDS in breast cancer patients. The search strategy
generated 149 titles, of which six were best placed to answer the clinical
question. These included three prospective cohort studies, two retrospective
cohort studies and one case control study, examining a total of 18,415 breast
cancer patients. The study methodologies were highly variable and all relied on
approximate measures of NSAID consumption. There is limited evidence that use of
aspirin and non-aspirin NSAIDs may be associated with decreased breast cancer
mortality and all-cause mortality in patients diagnosed with breast cancer.
Optimum type and dosage of NSAID for this purpose remains unclear. There is a
need for large-scale randomised controlled trials to further clarify. IMPORTANCE: The US Preventive Services Task Force recently recommended the use
of aspirin to prevent colorectal cancer and cardiovascular disease among many US
adults. However, the association of aspirin use with the risk for other cancer
types and the potential population-wide effect of aspirin use on cancer,
particularly within the context of screening, remain uncertain.
OBJECTIVES: To examine the potential benefits of aspirin use for overall and
subtype-specific cancer prevention at a range of doses and durations of use and
to estimate the absolute benefit of aspirin in the context of screening.
DESIGN, SETTING, AND PARTICIPANTS: Two large US prospective cohort studies, the
Nurses' Health Study (1980-2010) and Health Professionals Follow-up Study
(1986-2012), followed up 135 965 health care professionals (88 084 women and
47 881 men, respectively) who reported on aspirin use biennially. The women were
aged 30 to 55 years at enrollment in 1976; the men, aged 40 to 75 years in 1986.
Final follow-up was completed on June 30, 2012, for the Nurses' Health Study
cohort and January 31, 2010, for the Health Professionals Follow-up Study
cohort, and data were accessed from September 15, 2014, to December 17, 2015.
MAIN OUTCOMES AND MEASURES: Relative risks (RRs) for incident cancers and
population-attributable risk (PAR).
RESULTS: Among the 88 084 women and 47 881 men who underwent follow-up for as
long as 32 years, 20 414 cancers among women and 7571 cancers among men were
documented. Compared with nonregular use, regular aspirin use was associated
with a lower risk for overall cancer (RR, 0.97; 95% CI, 0.94-0.99), which was
primarily owing to a lower incidence of gastrointestinal tract cancers (RR,
0.85; 95% CI, 0.80-0.91), especially colorectal cancers (RR, 0.81; 95% CI,
0.75-0.88). The benefit of aspirin on gastrointestinal tract cancers appeared
evident with the use of at least 0.5 to 1.5 standard aspirin tablets per week;
the minimum duration of regular use associated with a lower risk was 6 years.
Among individuals older than 50 years, regular aspirin use could prevent 33
colorectal cancers per 100 000 person-years (PAR, 17.0%) among those who had not
undergone a lower endoscopy and 18 colorectal cancers per 100 000 person-years
(PAR, 8.5%) among those who had. Regular aspirin use was not associated with the
risk for breast, advanced prostate, or lung cancer.
CONCLUSIONS AND RELEVANCE: Long-term aspirin use was associated with a modest
but significantly reduced risk for overall cancer, especially gastrointestinal
tract tumors. Regular aspirin use may prevent a substantial proportion of
colorectal cancers and complement the benefits of screening. BACKGROUND: Through search the possible randomized control trials, we make a
renewed meta-analysis in order to assess the impact of aspirin in preventing the
recurrence of colorectal adenoma.
MATERIALS AND METHODS: The Medicine/PubMed, Embase, Cochrane Central Register of
Controlled Trials (CENTRAL), Chinese biomedical literature service system
(SinoMed) databases were searched for the related randomized controlled trials
until to the April 2016. Three different authors respectively evaluated the
quality of studies and extracted data, and we used the STATA software to
analyze, investigate heterogeneity between the data, using the fixed-effects
model to calculate and merge data.
RESULTS: 7 papers were included the renewed meta- analysis, among these studies,
two pairs were identified as representing the same study population, with the
only difference being the duration of follow-up. Thus there were only five
papers included our meta-analysis, and one Chinese paper were also included the
work. Results were categorized by the length of follow-up, different kinds of
people, varied dose of oral aspirin. The relative of adenoma in patients taking
aspirin vs placebo were 0.73 (95% CI 0.55-0.98, P=0.039) with 1 year follow up;
0.84 (95% CI 0.72-0.98, P=0.484) with greater than 1 year follow up; for the
advanced adenoma, the RR 0.68 (95% CI 0.49-0.94, P=0.582),for one year; RR=0.75
(95% CI 0.52-1.07, P=0.552) for greater one year. Furthermore the white
population could divided into two subgroups according to the different length of
follow-up time. When the length of follow-up time less than 3-year, The RR of
two subgroups respective were RR=0.86 (95% CI 0.76-0.98, P=0.332), I2=0%,
RR=0.68 (95% CI 0.47-0.98, P=0.552), I2=64.6%, But with the extension of
follow-up time greater than 2-year, with the white, oral aspirin without
considering dose had no efficacy on preventing the recurrence of any adenoma,
the RR was 0.86 (95% CI 0.71-1.05, P=0.302), I2=16.4%.
CONCLUSIONS: This meta-analysis indicated that oral aspirin is associated with a
remarkable decrease in the recurrence of any adenoma and advanced adenomas in
patients follow-up for 1 year without concerning the dose of aspirin, but with
the extension of follow-up time for greater than 1 year, oral aspirin can be
effective on preventing the recurrence of any adenoma, but for the advanced
adenoma, the result indicated that oral aspirin had no efficacy, According to
the inclusion of ethnic groups, we also divided relevant papers into two
subgroups as the yellow and white group. Then the follow-up time was less than 3
years, oral aspirin without considering the dose, had an significant efficacy on
preventing the recurrence of any adenoma. But with the follow-up greater than 2
years, oral aspirin had no effect in the white. Considerable interest has emerged over the last decade regarding the role of
aspirin in prevention of colorectal cancer. This disease is one of the commonest
cancers in the Western World, therefore, the existence of a simple "everyday"
agent, which could have the ability to prevent the disease, represents an
invaluable opportunity clinicians may be able to exploit. Evidence from
case-control and cohort studies, and recent updates of randomised controlled
trials have been very encouraging-indicating benefit from long term use of
aspirin at low dose. Possible mechanisms of chemoprevention include inhibition
of the cyclooxygenase (COX) pathway, or COX-independent mechanisms, for example,
the PIK3CA pathway, or therapy-induced senescence of cancer cells. The most
serious side effect of prolonged aspirin treatment is haemorrhage, especially
from the GI tract. This is likely to be less of a problem with chemoprevention
at lower doses. One also needs to consider the impact if aspirin resistance, an
increasingly recognised clinical entity. BACKGROUND: Colorectal cancer (CRC) is one of the most common cancers in the
developed world and is the second leading cause of cancer-related mortality in
the UK and USA. Regular use of aspirin can reduce cancer incidence, recurrence,
metastasis and cancer-related mortality.
SOURCES OF DATA: Peer-reviewed journals, governmental and professional society
publications.
AREAS OF AGREEMENT: There is a wide body of evidence from observational studies
and randomized trials that aspirin reduces risk of CRC. There is a delay of
several years between initiation and effect. There is interpersonal variation in
aspirin metabolism but pharmacogenetic testing is not yet sufficiently sensitive
or specific to justify routine use.
AREAS OF DISAGREEMENT: There is uncertainty about the optimal dose and the
duration of aspirin. There is debate around use for the general population but
there is growing consensus on use in those at increased risk of developing
cancer.
GROWING POINTS: Understanding is growing of the possible mechanisms by which
aspirin exerts its anticancer effects. Large-scale meta-analyses are quantifying
the cost-benefit ratio in the general population. International trials are
underway to assess the optimal dose in high-risk individuals and the role of
aspirin as an adjuvant in those who present with a maligcy. PURPOSE: Studies suggest that aspirin, other nonsteroidal anti-inflammatory
drugs (NSAIDs), and statins may reduce risk of some cancers. However, findings
have been conflicting as to whether these agents reduce the risk of pancreatic
cancer.
METHODS: We used data from the Queensland Pancreatic Cancer Study, a
population-based case-control study. In total, 704 cases and 711 age- and
sex-matched controls were recruited. Participants completed an interview in
which they were asked about history of NSAID and statin use. We included 522
cases and 653 controls who had completed the medication section of the interview
in this analysis. Unconditional multivariable logistic regression was used to
estimate associations between medication use and pancreatic cancer.
RESULTS: We found no consistent evidence of an association between use of NSAIDs
or statins and risk of pancreatic cancer. There was some suggestion of a
protective effect in infrequent users of selective COX-2 inhibitors, but no
association in more frequent users. We did not find evidence of protective
effects in analyses stratified by sex, smoking status, time between diagnosis
and interview, or presence/absence of metastases.
CONCLUSIONS: Overall, our results do support the hypothesis that use of NSAIDs
or statins may reduce the odds of developing pancreatic cancer. |
Which are the components of the pre-replication complex (pre-RC) in eukaryotes? | The components of the pre-replication complex (pre-RC) in eukaryotes are:
1) Cdc6/Cdc18,
2) MCM,
3) ORC1-6,
4) Cdt1 and
5) Sap1/Gi. | The overall organization of cell division in Plasmodium is unique compared to
that observed in model organisms because DNA replicates more than once per cell
cycle at several points of its life cycle. The sequencing of the Plasmodium
genome has also revealed the apparent absence of many key components (e.g. Cdt1,
DDK and Cdc45) of the eukaryotic cell cycle machinery that are responsible for
the formation of the pre-replication complex (pre-RC). We have characterized the
Plasmodium falciparum minichromosome maintece complex (MCM) that plays a key
role in the transition of pre-RC to the RC. Similar to other eukaryotes, the
Plasmodium genome encodes six MCM subunits. Here, we show that expression levels
of at least three of the PfMCM subunits, the homologues of MCM2, MCM6 and MCM7,
change during the intraerythrocytic development cycle, peaking in schizont and
decreasing in the ring and trophozoite stages. PfMCM2, 6 and 7 subunits interact
with each other to form a developmentally regulated complex: these interactions
are detectable in rings and schizonts, but not in trophozoites. PfMCM2, 6 and 7
subunits are localized in both cytosolic and nucleosolic fractions during all
intraerythrocytic stages of P. falciparum development, with increased nuclear
localization in schizonts. Only PfMCM6 is associated with the chromatin fraction
at all stages of growth. No phosphorylation of PfMCM2, 6 and 7 was detected, but
two as yet unidentified threonine-phosphosphorylated proteins were present in
the complex, whose pattern of phosphorylation varied during parasite
development. Origins of replication are expected to recruit initiation proteins like origin
recognition complex (ORC) and Cdc6 in eukaryotes and provide a platform for
unwinding DNA. Here we test whether localization of initiation proteins onto DNA
is sufficient for origin function. Different components of the ORC complex and
Cdc6 stimulated prereplicative complex (pre-RC) formation and replication
initiation when fused to the GAL4 DNA-binding domain and recruited to plasmid
DNA containing a tandem array of GAL4-binding sites. Replication occurred once
per cell cycle and was inhibited by Geminin, indicating that the plasmid was
properly licensed during the cell cycle. The GAL4 fusion protein recruits other
polypeptides of the ORC-Cdc6 complex, and nascent strand abundance was highest
near the GAL4-binding sites. Therefore, the artificial origin recapitulates many
of the regulatory features of physiological origins and is valuable for studies
on replication initiation in mammalian cells. We demonstrated the utility of
this system by showing the functional importance of the ATPase domains of human
Cdc6 and Orc1 and the dispensability of the N-terminal segments of Orc1 and Orc2
in this assay. Artificial recruitment of a eukaryotic cellular replication
initiation factor to a DNA sequence can create a functional origin of
replication, providing a robust genetic assay for these factors and a novel
approach to generating episomal vectors for gene therapy. Replication of eukaryotic genomes is limited to once per cell cycle, by a
two-step mechanism. DNA replication origins are first "licensed" during G1 phase
by loading of an inactive DNA helicase (Mcm2-7) into pre-replicative complexes
(pre-RCs). Initiation then occurs during S phase, triggered by cyclin-dependent
kinases (CDKs), which promote recruitment of proteins required for helicase
activation and replisome assembly. CDKs and the anaphase promoting
complex/cyclosome (APC/C) restrict licensing to G1 phase by directly and
indirectly regulating pre-RC components, including ORC, Cdc6, Cdt1, and Mcm2-7.
Despite the fundamental importance of licensing regulation, the mechanisms by
which pre-RC components are regulated differ widely across Eukarya. Here we show
that even within the genus Saccharomyces, Cdc6 is regulated differently in
different species. We propose that two factors contribute to the rapid evolution
of licensing regulation. The first is redundancy: eliminating any single
pre-RC-regulatory mechanism has very little affect on viability. The second is
interchangeability: we show that regulatory mechanisms can be swapped between
pre-RC components without compromising the block to re-replication. These
experiments provide a framework for understanding the diversity of licensing
regulation in eukaryotes and provide new tools for manipulating the
chromosome-replication cycle. In higher eukaryotes, the pre-replication complex (pre-RC) component Cdt1 is the
major regulator in licensing control for DNA replication. The Cul4-DDB1-based
ubiquitin ligase mediates Cdt1 ubiquitylation for subsequent proteolysis. During
the initiation of chorion gene amplification, Double-parked (Dup), the
Drosophila ortholog of Cdt1, is restricted to chorion gene foci. We found that
Dup accumulated in nuclei in Cul4 mutant follicle cells, and the accumulation
was less prominent in DDB1 mutant cells. Loss of Cul4 or DDB1 activity in
follicle cells also compromised chorion gene amplification and induced ectopic
genomic DNA replication. The focal localization of Orc2, a subunit of the origin
recognition complex, is frequently absent in Cul4 mutant follicle cells.
Therefore, Cul4 and DDB1 have differential functions during chorion gene
amplification. The pre-replicative complex (pre-RC) is formed at all potential origins of
replication through the action of the origin recognition complex (ORC), Cdc6,
Cdt1, and the Mcm2-7 complex. The end result of pre-RC formation is the loading
of the Mcm2-7 replicative helicase onto origin DNA. We examined pre-RC formation
in vitro and found that it proceeds through separable binding events.
Origin-bound ORC recruits Cdc6, and this ternary complex then promotes helicase
loading in the presence of a pre-formed Mcm2-7-Cdt1 complex. Using a stepwise
pre-RC assembly assay, we investigated the fate of pre-RC components during
later stages of the reaction. We determined that helicase loading is accompanied
by dissociation of ORC, Cdc6, and Cdt1 from origin DNA. This dissociation
requires ATP hydrolysis at a late stage of pre-RC assembly. Our results indicate
that pre-RC formation is a dynamic process. Several replication-initiation proteins are assembled stepwise onto replicators
to form pre-replicative complexes (pre-RCs) to license eukaryotic DNA
replication. We performed a yeast functional proteomic screen and identified the
Rix1 complex members (Ipi1p-Ipi2p/Rix1-Ipi3p) as pre-RC components and critical
determits of replication licensing and replication-initiation frequency.
Ipi3p interacts with pre-RC proteins, binds chromatin predomitly at ARS
sequences in a cell cycle-regulated and ORC- and Noc3p-dependent manner and is
required for loading Cdc6p, Cdt1p and MCM onto chromatin to form pre-RC during
the M-to-G₁ transition and for pre-RC maintece in G₁ phase-independent of its
role in ribosome biogenesis. Moreover, Ipi1p and Ipi2p, but not other ribosome
biogenesis proteins Rea1p and Utp1p, are also required for pre-RC formation and
maintece, and Ipi1p, -2p and -3p are interdependent for their chromatin
association and function in pre-RC formation. These results establish a new
framework for the hierarchy of pre-RC proteins, where the Ipi1p-2p-3p complex
provides a critical link between ORC-Noc3p and Cdc6p-Cdt1p-MCM in replication
licensing. DNA replication in all eukaryotes starts with the process of loading the
replicative helicase MCM2-7 onto chromatin during late mitosis of the cell
cycle. MCM2-7 is a key component of the prereplicative complex (pre-RC), which
is loaded onto chromatin by the concerted action of origin recognition complex,
Cdc6, and Cdt1. Here, we demonstrate that And-1 is assembled onto chromatin in
late mitosis and early G(1) phase before the assembly of pre-RC in human cells.
And-1 forms complexes with MCM2-7 to facilitate the assembly of MCM2-7 onto
chromatin at replication origins in late mitosis and G(1) phase. We also present
data to show that depletion of And-1 significantly reduces the interaction
between Cdt1 and MCM7 in G(1) phase cells. Thus, human And-1 facilitates loading
of the MCM2-7 helicase onto chromatin during the assembly of pre-RC. Chromosomal DNA replication is one of the central biological events occurring
inside cells. Due to its large size, the replication of genomic DNA in
eukaryotes initiates at hundreds to tens of thousands of sites called DNA
origins so that the replication could be completed in a limited time. Further,
eukaryotic DNA replication is sophisticatedly regulated, and this regulation
guarantees that each origin fires once per S phase and each segment of DNA gets
duplication also once per cell cycle. The first step of replication initiation
is the assembly of pre-replication complex (pre-RC). Since 1973, four proteins,
Cdc6/Cdc18, MCM, ORC and Cdt1, have been extensively studied and proved to be
pre-RC components. Recently, a novel pre-RC component called Sap1/Girdin was
identified. Sap1/Girdin is required for loading Cdc18/Cdc6 to origins for pre-RC
assembly in the fission yeast and human cells, respectively. At the transition
of G1 to S phase, pre-RC is activated by the two kinases, cyclindependent kinase
(CDK) and Dbf4-dependent kinase (DDK), and subsequently, RPA, primase-polα,
PCNA, topoisomerase, Cdc45, polδ, and polɛ are recruited to DNA origins for
creating two bi-directional replication forks and initiating DNA replication. As
replication forks move along chromatin DNA, they frequently stall due to the
presence of a great number of replication barriers on chromatin DNA, such as
secondary DNA structures, protein/DNA complexes, DNA lesions, gene
transcription. Stalled forks must require checkpoint regulation for their
stabilization. Otherwise, stalled forks will collapse, which results in
incomplete DNA replication and genomic instability. This short review gives a
concise introduction regarding the current understanding of replication
initiation and replication fork stabilization. Recent clinical studies have raised the clinically important question of the
relationship between dihydrotestosterone (DHT) and prostate cancer (PCa)
progression. The significance of DHT or 5α-reductase inhibitors (5ARI) in PCa
development and progression has not yet been fully characterized. The aim of
this study was to determine whether the initiation of DNA replication was
influenced by DHT in PCa. Three cell lines were used. LNCaP: a human PCa cell
line that exhibits androgen-dependent proliferation, C4-2: a human PCa cell line
that exhibits androgen-independent proliferation, and C4-2AT6: a castration
resistant prostate cancer cell line. Two 5ARIs, finasteride and dutasteride,
were used. We examined the mRNA expression of the components of pre-replication
complex (Pre-RC), CDC6, CDT1, and MCM2-7. DHT induced cell proliferation of
LNCaP accompanied by significantly increased CDC6, CDT1, and MCM2-7 expression.
In contrast to LNCaP, DHT inhibited cell proliferation in C4-2AT6 cells
accompanied by decreased expression of CDC6, CDT1, and MCM2-7. These reverse
effects resemble the effects of 5ARIs in Pre-RC. Treatment with finasteride or
dutasteride inhibited CDC6 expression in LNCaP, but both 5ARIs induced CDC6
expression in C4-2 and C4-2AT6 cells.These results indicate that DHT showed
reversal effects on PCa cell proliferation among prostate cancer cells based on
androgen-dependence, accompanied by regulation of the initiation of DNA
replication. 5ARIs may modulate the DNA replication system in someaggressive PCa
through up-regulation of CDC6 expression. |
What is the inheritance of hypophosphatemic rickets? | Hypophosphatemic rickets are transmitted with:
1) autosomal recessive
2) autosomal dominant
3) X-linked recessive and
4) X-linked dominant inheritance. | X-linked familial hypophosphatemic rickets (X.L.F.H.R.) is one of the D
resistant rickets. The inheritance pattern is related to the X chromosome. Most
constant feature is hypophosphatemia. Pathogenesis is still a subject of
controversy. There are three main theories: a) An abnormal vitamin D metabolism.
b) Secondary hyperparathyroidism developping as a result of the diminished
calcium absorption by gut. c) A primary deffect of phosphate transport al
various levels. Authors study and comment six cases of X.L.F.H.R., three of
which belong to the same family. Clinical, radiological and higtological
findings correspond to those of severe rickets. It is a chronic disease which
affects children during growth period, giving rise to deforming bones
invalidism. Treatment consists on continuous administration of oral phosphate
and vitamin D. A familial observation of hypophosphatemic rickets with unusual inheritance and
evolution, different from that of X linked hypophosphatemia, is reported. The
mode of inheritance was autosomal domit, a father and his son being affected.
Severe early signs of rickets and delayed growth were present in both cases.
Plasma 1,25 dihydroxyvitamin D and PTH levels were normal. There was no
hypercalciuria. Complete cure of rickets and catch-up growth were obtained with
the only treatment of vitamin D (40,000 U/day) in the father and of 1 alpha
hydroxyvitamin D (1 microgram/day) in the son. This observation is quite similar
to the 'autosomal hypophosphatemic bone disease' described by Scriver et al. It
illustrates the heterogeneity of familial hypophosphatemia which presently
includes 4 different physiopathological entities. We report two cases of x-linked domit hypophosphatemic rickets involving a
man and his daughter. The family tree consists of 44 members with 13 of them
having short stature and bowing of the lower limbs. The study of this family
tree strongly suggests an x-linked domit inheritance. CONTEXT: Familial hypophosphatemic rickets is usually transmitted as an X-linked
domit disorder (XLH), although autosomal domit forms have also been
observed. Genetic studies of these disorders have identified mutations in PHEX
and FGF23 as the causes of X-linked domit disorder and autosomal domit
forms, respectively.
OBJECTIVE: The objective of the study was to describe the molecular genetic
findings in a family affected by hypophosphatemic rickets with presumed
autosomal domit inheritance.
PATIENTS: We studied a family in which the father and the elder of his two
daughters, but not the second daughter, were affected by hypophosphatemic
rickets. The pedigree interpretation of the family suggested that genetic
transmission of the disorder occurred as an autosomal domit trait.
METHODS AND RESULTS: Direct nucleotide sequencing of FGF23 and PHEX revealed
that the elder daughter was heterozygous for an R567X mutation in PHEX, rather
than FGF23, suggesting that the genetic transmission occurred as an X-linked
domit trait. Unexpectedly, the father was heterozygous for this mutation.
Single-nucleotide primer extension and denaturing HPLC analysis of the father
using DNA from single hair roots revealed that he was a somatic mosaic for the
mutation. Haplotype analysis confirmed that the father transmitted the genotypes
for 18 markers on the X chromosome equally to his two daughters. The fact that
the father transmitted the mutation to only one of his two daughters indicated
that he was a germline mosaic for the mutation.
CONCLUSIONS: Somatic and germline mosaicism for an X-linked domit mutation in
PHEX may mimic autosomal domit inheritance. Hypophosphatemia due to isolated renal phosphate wasting is a genetically
heterogeneous disease. Two new genes linked to two different forms of hereditary
hypophosphatemias have recently been described. Autosomal recessive form of
hypophosphatemic rickets was mapped to chromosome 4q21 and identified homozygous
mutations in dentin matrix protein 1 (DMP1) gene, which encodes a
non-collagenous bone matrix protein. Intact plasma levels of the phosphaturic
protein FGF23 (fibroblast growth factor 23) were clearly elevated in some of the
affected individuals, providing a possible explanation for the phosphaturia and
inappropriately normal 1,25(OH)2D levels, and suggesting that DMP1 may regulate
FGF23 expression. Hereditary hypophosphatemic rickets with hypercalciuria is
another rare disorder of autosomal recessive inheritance. Affected individuals
present with hypercalciuria due to increased serum 1,25-dihydroxyvitamin D
levels and increased intestinal calcium absorption. The disease was mapped to a
1.6 Mbp region on chromosome 9q34, which contains SLC34A3, the gene encoding the
renal sodium-phosphate cotransporter NaPi-IIc. This was the first demonstration
that NaPi-IIc has a key role in the regulation of phosphate homeostasis. Thus,
DMP1 and NaPi-IIc add two new members to the bone-kidney axis proposed since it
was discovered that the first phosphatonin, FGF23, was of osteoblastic/osteocyte
origin. This provides a mechanism for the skeleton to communicate with the
kidney to coordinate the mineralization of extracelular matrix and the renal
handling of phosphate. We previously demonstrated that the mutations Met1Val (M1V) and the deletion of
nucleotides 1484-1490 (1484-1490del) in Dentin matrix protein-1 (DMP1) cause the
novel disorder autosomal recessive hypophosphatemic rickets (ARHR), which is
associated with elevated fibroblast growth factor-23 (FGF23). To further
understand the role of DMP1 in ARHR, we undertook molecular genetic and in vitro
expression studies. First, we examined a kindred with a severe hypophosphatemic
rickets phenotype and recessive inheritance. Analyses of this family
demonstrated that the affected members had elevated serum FGF23 and carried a
large, biallelic deletion that removed the majority of DMP1. At a minimum, this
deletion encompassed 49 kb between DMP1 exon 3 and an intergenic region 5' to
the next telomeric gene, integrin-binding sialoprotein (IBSP). We next performed
immunofluorescent studies in cells to understand the effects of the known ARHR
mutations on DMP1 cellular processing. These analyses showed that the M1V DMP1
mutant was not sorted to the trans-Golgi network (TGN) and secretory pathway,
but filled the entire cytoplasm. In contrast, the 1484-1490del mutant localized
to the TGN and was secreted, similar to wild type DMP1. The 1484-1490del
mutation replaces the DMP1 18 C-terminal amino acids with 33 non-native
residues. Truncation of wild type DMP1 by these native 18 residues followed by
Western blot and confocal microscopic analyses demonstrated a wild type
expression pattern when compared with the 1484-1490del mutant, indicating that
the last 18 residues are not critical for cellular trafficking, but that the 33
additional residues arising from the 1484-1490del mutation likely compromise
DMP1 processing. The relationship between DMP1 and FGF23 is unclear. To test
endogenous DMP1 response to serum metabolites that also regulate FGF23, UMR-106
cells were treated with 1,25(OH)(2) vitamin D (1x10(-7) M) and showed a 12-fold
increase in DMP1 mRNA and protein at 24 h. In summary, we have identified a
novel DMP1 deletion as the cause of ARHR, as well as demonstrated that the ARHR
mutations alter DMP1 cellular processing, and that DMP1 can be regulated by
vitamin D. Taken together, this work expands our understanding of the genetic
and molecular mechanisms associated with DMP1 alterations causing ARHR. Autosomal recessive hypophosphatemic rickets (ARHR) is an extremely rare
disorder of autosomal recessive inheritance, characterized by hypophosphatemia
resulting from renal phosphate wasting. Dentin matrix protein 1 (DMP1), a
noncollagenous extracellular protein, plays critical roles in bone
mineralization and phosphate homeostasis. Recently, loss-of-function mutations
in DMP1 gene have been identified as the molecular cause of ARHR. Here, we
describe a Japanese family that includes two ARHR-affected siblings carrying a
novel mutation of the DMP1 gene. The patients were a 53-year-old woman and a
50-year-old man with short stature and skeletal deformities who were the
offspring of a first-cousin marriage. Biochemical examination revealed
hypophosphatemia with renal phosphate excretion and low levels of 1,25(OH)(2)D.
Serum calcium, parathyroid hormone, and urinary calcium excretion were within
the normal range, leading to clinical diagnosis of ARHR. Sequence analysis of
peripheral leukocytes from the patients revealed that they carried a novel
homozygous nonsense mutation in the DMP1 gene (98G>A, W33X), which leads to a
truncated DMP protein with no putative biological function. Unaffected family
members were heterozygous for the mutation. This is the first report of a
Japanese family with ARHR carrying a novel mutation of the DMP1 gene. BACKGROUND: X-linked hypophosphatemia (XLH) is the most common form of heritable
rickets characterized by X-linked domit inheritance, renal phosphate wasting,
hypophosphatemia, and defective bone mineralization. Inactivating mutations of
the PHEX gene located at Xp22.1 have been linked with this disease. Ethnic
distribution of such mutations seems widespread but only a few mutations in the
Chinese population have been reported to date.
MATERIALS AND METHODS: We report on a large Han Chinese family affected with XLH
rickets, which included 13 patients from four generations. Polymerase chain
reaction and direct sequencing were performed for all exons and intron-exon
boundaries of the PHEX gene. The effect of nucleotide changes was analyzed using
bioinformatic software. Prenatal diagnosis was performed on umbilical cord blood
at the 20th gestational week.
RESULTS: A novel G-->A splice mutation in intron 7 (c.849+1G>A) was identified
in all patients from the family. As confirmed by reverse-transcription
(RT)-polymerase chain reaction (PCR), the mutation has rendered loss of a normal
splice donor site (c.849+1G) while activating a cryptic one at c.849+519G, which
resulted in addition of 518 nucleotides to the mature RNA. Prenatal diagnosis
had excluded the fetus for carrying the same mutation. A healthy boy was born
later.
CONCLUSIONS: A novel splice mutation c.849+1G>A in the PHEX gene is responsible
for XLH in the studied family. Further studies may enhance our understanding of
the role of this mutation in the pathogenesis of XLH. PURPOSE OF REVIEW: Description of the recent advances on the regulation of
phosphate metabolism, gene mutations, and new approaches to treatment in
patients with hypophosphatemic rickets.
RECENT FINDINGS: Fibroblast growth factor 23 (FGF23) overproduction may be a
primary cause of hypophosphatemic rickets. Inactivating mutations of
phosphate-regulating gene with homologies to endopeptidases on the X chromosome,
dentin matrix acidic phosphoprotein 1, and ectonucleotide
pyrophosphatase/phosphodiesterase 1 are associated with X-linked
hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets 1, and
autosomal recessive hypophosphatemic rickets 2, respectively. Activating
mutations of FGF23 gene is the cause of autosomal domit hypophosphatemic
rickets. Iron deficiency may affect autosomal domit hypophosphatemic rickets
phenotype by regulating FGF23 production.Current treatment with activated
vitamin D metabolites and oral inorganic phosphate salts may partially correct
skeletal lesions and linear growth in patients with hypophosphatemic rickets.
However, some patients have poor improvement by the current treatment.
SUMMARY: Identification of the causative mutation in patients with
hypophosphatemic rickets may be useful to confirm the diagnosis and probably for
prognosis. Inhibition of FGF23 overproduction by anti-FGF23 neutralizing
antibodies could be a future approach for treatment of patients with
FGF23-dependent hypophosphatemic rickets. |
Which mushroom is poisonous, Amanita phalloides or Agaricus Bisporus | The well-known cultivated species Agaricus bisporus is safe to eat while Amanita Phalloides is poisonous. | Seventeen edible mushrooms commercially available in Korea were analysed for
their umami taste compounds (5'-nucleotides: AMP, GMP, IMP, UMP, XMP; free amino
acids: aspartic, glutamic acid) and subjected to human sensory evaluation and
electronic tongue measurements. Amanita virgineoides featured the highest total
5'-nucleotide content (36.9 ± 1.50 mg/g), while monosodium glutamate-like
components (42.4 ± 6.90 mg/g) were highest in Agaricus bisporus. The equivalent
umami concentration (EUC) ranged from 1.51 ± 0.42 to 3890 ± 833 mg MSG/g dry
weight; most mushrooms exhibited a high umami taste. Pleurotus ostreatus scored
the highest in the human sensory evaluation, while Flammulina velutipes obtained
the maximum score in the electronic tongue measurement. The EUC and the sensory
score from the electronic tongue test were highly correlated, and also showed
significant correlation with the human sensory evaluation score. These results
suggest that the electronic tongue is suitable to determine the characteristic
umami taste of mushrooms. Author information:
(1)Competence Center for Applied Mycology and Environmental Studies, Niederrhein
University of Applied Sciences, Rheydter Str. 277, 41065 Mönchengladbach,
Germany; Institute for Virology and Microbiology, University of Witten/Herdecke,
Stockumer Strasse 10, 58453 Witten, Germany. Electronic address:
[email protected].
(2)Competence Center for Applied Mycology and Environmental Studies, Niederrhein
University of Applied Sciences, Rheydter Str. 277, 41065 Mönchengladbach,
Germany; Institute for Virology and Microbiology, University of Witten/Herdecke,
Stockumer Strasse 10, 58453 Witten, Germany; Center for Advanced Microstructures
and Devices (CAMD), Louisiana State University, 6980 Jefferson Highway, Baton
Rouge, LA 70806, USA.
(3)Competence Center for Applied Mycology and Environmental Studies, Niederrhein
University of Applied Sciences, Rheydter Str. 277, 41065 Mönchengladbach,
Germany; GAMU GmbH, Hüttenallee 241, 47800 Krefeld, Germany.
(4)Competence Center for Applied Mycology and Environmental Studies, Niederrhein
University of Applied Sciences, Rheydter Str. 277, 41065 Mönchengladbach,
Germany. |
Which is the most common gene signature in Rheumatoid Arthritis patients? | A five gene type I IFN signature was assessed in these subjects to identify subpopulations showing both activation and concordance of the type I IFN pathway in the peripheral blood and disease-affected tissues of each disease and to correlate activation of this pathway in the WB with clinical measurements.R Baseline disease activity measurements correlated with a type I IFN gene signature in the WB of subjects with SLE, PM and SSc, as did various serum autoantibody levels in subjects with SLE and DM. | Susceptibility to autoimmune disorders results from the interaction of multiple
genetic factors that regulate the threshold of autoreactivity. Genome-wide
microsatellite screens and large-scale single nucleotide polymorphism (SNP)
association studies have identified chromosomal loci that are associated with
specific disorders including systemic lupus erythematosus, rheumatoid arthritis,
juvenile arthritis, multiple sclerosis, and diabetes. Numerous candidate gene
association studies have in turn investigated the association of specific genes
within these chromosomal regions, with susceptibility to autoimmune diseases
(e.g. FcgammaReceptors, TYK2 and systemic lupus). More recently, large-scale
differential gene expression studies performed on selected tissues from patients
with autoimmune disorders, have led to the identification of gene signatures
associated with the activation of specific pathways in these diseases (e.g.
interferon signature in lupus). In the future, integrated analyses of gene (and
protein) expression together with SNP data will allow us to sketch an
intelligible picture of the genesis of autoimmunity in humans. This review sets
out to illustrate how the most recent advances in the field of systemic lupus
erythematosus, rheumatoid arthritis and juvenile arthritis have led to a better
understanding of these disorders. Type I interferons play an outstanding role in innate and adaptive immunity by
enhancing functions of dendritic cells, inducing differentiation of monocytes,
promoting immunoglobulin class switching in B cells and stimulating effector
functions of T cells. The increased production of IFNα/β by plasmacytoid
dendritic cells could be responsible for not only efficient antiviral defence,
but it also may be a pathological factor in the development of various
autoimmune disorders. The first evidence of a genetic link between type I
interferons and autoimmune diseases was the observation that elevated IFNα
activity is frequently detected in the sera of patients with systemic lupus
erythematosus, and that this trait shows high heritability and familial
aggregation in their first-degree healthy relatives. To date, a number of genes
involved in interferon signalling have been associated with various autoimmune
diseases. Patients with systemic lupus erythematosus, Sjögren's syndrome,
dermatomyositis, psoriasis, and a fraction of patients with rheumatoid arthritis
display a specific expression pattern of interferon-dependent genes in their
leukocytes, termed the interferon signature. Here, in an attempt to understand
the role of type I interferons in the pathogenesis of autoimmunity, we review
the recent advances in the genetics of autoimmune diseases focusing on the
association of genes involved in type I interferon pathways. OBJECTIVE: To analyze the relationship between the type I interferon (IFN)
signature and clinical response to rituximab in rheumatoid arthritis (RA)
patients.
METHODS: Twenty RA patients were treated with rituximab (cohort 1). Clinical
response was defined as a decrease in the Disease Activity Score evaluated in 28
joints (DAS28) and as a response according to the European League Against
Rheumatism (EULAR) criteria at week 12 and week 24. The presence of an IFN
signature was analyzed in peripheral blood mononuclear cells by measuring the
expression levels of 3 IFN response genes by quantitative polymerase chain
reaction analysis. After comparison with the findings in healthy controls,
patients were classified as having an IFN high or an IFN low signature. The data
were confirmed in a second independent cohort (n = 31). Serum IFNα bioactivity
was analyzed using a reporter assay.
RESULTS: In cohort 1, there was a better clinical response to rituximab in the
IFN low signature group. Consistent with these findings, patients with an IFN
low signature had a significantly greater reduction in the DAS28 and more often
achieved a EULAR response at weeks 12 and 24 as compared with the patients with
an IFN high signature in cohort 2 versus cohort 1. The pooled data showed a
significantly stronger decrease in the DAS28 in IFN low signature patients at
weeks 12 and 24 as compared with the IFN high signature group and a more
frequent EULAR response at week 12. Accordingly, serum IFNα bioactivity at
baseline was inversely associated with the clinical response, although this
result did not reach statistical significance.
CONCLUSION: The type I IFN signature negatively predicts the clinical response
to rituximab treatment in patients with RA. This finding supports the notion
that IFN signaling plays a role in the immunopathology of RA. A significant role for IFNα in the pathogenesis of systemic lupus erythematosus
is well supported, and clinical trials of anti-IFNα monoclonal antibodies are in
progress in this disease. In other autoimmune diseases characterized by
substantial inflammation and tissue destruction, the role of type I interferons
is less clear. Gene expression analysis of peripheral blood cells from patients
with rheumatoid arthritis and multiple sclerosis demonstrate an interferon
signature similar to but less intense than that seen in patients with lupus. In
both of those diseases, presence of the interferon signature has been associated
with more significant clinical manifestations. At the same time, evidence
supports an anti-inflammatory and beneficial role of IFNβ locally in the joints
of patients with rheumatoid arthritis and in murine arthritis models, and many
patients with multiple sclerosis show a clinical response to recombit IFNβ.
As can also be proposed for type I diabetes mellitus, type I interferon appears
to contribute to the development of autoimmunity and disease progression in
multiple autoimmune diseases, while maintaining some capacity to control
established disease - particularly at local sites of inflammation. Recent
studies in both rheumatoid arthritis and multiple sclerosis suggest that
quantification of type I interferon activity or target gene expression might be
informative in predicting responses to distinct classes of therapeutic agents. INTRODUCTION: The finding of antinuclear antibody (ANA) positivity in a healthy
individual is usually of unknown significance and in most cases is benign.
However, a subset of such individuals is at risk for development of autoimmune
disease. We examined demographic and immunological features that are associated
with ANA positivity in clinically healthy persons to develop insights into when
this marker carries risk of progression to lupus.
METHODS: Biological samples from healthy individuals and patients with systemic
lupus erythematosus (SLE) were obtained from the Dallas Regional Autoimmune
Disease Registry (DRADR). Measurements carried out on serum samples included
ANA, extractable nuclear antibodies (ENA) and autoantibody profiling using an
array with more than 100 specificities. Whole blood RNA samples from a subset of
individuals were used to analyze gene expression on the Illumina platform. Data
were analyzed for associations of high ANA levels with demographic features, the
presence of other autoantibodies and with gene expression profiles.
RESULTS: Overall, ANA levels are significantly higher in females than in males
and this association holds in patients with the autoimmune diseases lupus and
rheumatoid arthritis (RA) as well as in healthy controls (HC). Age was not
significantly associated with ANA levels and the elevated ANA values could not
be explained by higher IgG levels. Another autoantibody, anti- cyclic
citrullinated peptide (CCP), did not show gender dimorphism in rheumatoid
arthritis (RA) or healthy individuals. The autoantigen array showed significant
elevations of other autoantibodies in high ANA HCs. Some of these autoantibodies
were directed to antigens in skin and others were related to autoimmune
conditions of kidney, thyroid or joints. Gene expression analyses showed a
greater prevalence of significantly upregulated genes in HCs with negative ANA
values than in those with significant ANA positivity. Genes upregulated in high
ANA HCs included a celiac disease autoantigen and some components of the Type I
interferon (IFN) gene signature.
CONCLUSIONS: Risks for ANA positivity include female gender and organ-specific
autoimmunity. Upregulation of skin-specific autoantibodies may indicate that
early events in the break of tolerance take place in cutaneous structures. Some
of these changes may be mediated by Type I IFN. Blood profiling for expressed
autoantibodies and genes has the potential to identify individuals at risk for
development of autoimmune diseases including lupus. OBJECTIVE: To characterise activation of the type I interferon (IFN) pathway in
patients with systemic lupus erythematosus (SLE), dermatomyositis (DM),
polymyositis (PM), rheumatoid arthritis (RA) and systemic scleroderma (SSc) and
to evaluate the potential to develop a molecular diagnostic tool from the
peripheral blood that reflects this activation in disease-affected tissues.
METHODS: Overexpressed transcripts were identified in the whole blood (WB) of
262 patients with SLE, 44 with DM, 33 with PM, 28 with SSc and 89 with RA and
compared with 24 healthy subjects using Affymetrix microarrays. A five gene type
I IFN signature was assessed in these subjects to identify subpopulations
showing both activation and concordance of the type I IFN pathway in the
peripheral blood and disease-affected tissues of each disease and to correlate
activation of this pathway in the WB with clinical measurements.
RESULTS: A common set of 36 type I IFN inducible transcripts were identified
among the most overexpressed in the WB of all subjects. Significant activation
of the type I IFN pathway in subgroups of each of the five diseases studied was
observed. Baseline disease activity measurements correlated with a type I IFN
gene signature in the WB of subjects with SLE, PM and SSc, as did various serum
autoantibody levels in subjects with SLE and DM. This signature was also well
correlated between disease-affected tissue and WB in subjects with SLE, DM, PM
and SSc.
CONCLUSIONS: The results indicate that the type I IFN pathway is activated in
patient subsets of five rheumatic diseases and suggest that these subsets may
benefit from anti-IFN therapy. BACKGROUND: The analysis of gene expression data shows that many genes display
similarity in their expression profiles suggesting some co-regulation. Here, we
investigated the co-expression patterns in gene expression data and proposed a
correlation-based research method to stratify individuals.
METHODOLOGY/PRINCIPAL FINDINGS: Using blood from rheumatoid arthritis (RA)
patients, we investigated the gene expression profiles from whole blood using
Affymetrix microarray technology. Co-expressed genes were analyzed by a
biclustering method, followed by gene ontology analysis of the relevant
biclusters. Taking the type I interferon (IFN) pathway as an example, a
classification algorithm was developed from the 102 RA patients and extended to
10 systemic lupus erythematosus (SLE) patients and 100 healthy volunteers to
further characterize individuals. We developed a correlation-based algorithm
referred to as Classification Algorithm Based on a Biological Signature (CABS),
an alternative to other approaches focused specifically on the expression
levels. This algorithm applied to the expression of 35 IFN-related genes showed
that the IFN signature presented a heterogeneous expression between RA, SLE and
healthy controls which could reflect the level of global IFN signature
activation. Moreover, the monitoring of the IFN-related genes during the
anti-TNF treatment identified changes in type I IFN gene activity induced in RA
patients.
CONCLUSIONS: In conclusion, we have proposed an original method to analyze genes
sharing an expression pattern and a biological function showing that the
activation levels of a biological signature could be characterized by its
overall state of correlation. The mechanisms by which environmental toxicants alter developmental processes
predisposing individuals to adult onset chronic disease are not well-understood.
Transplacental arsenic exposure promotes atherogenesis in apolipoprotein
E-knockout (ApoE(-/-)) mice. Because the liver plays a central role in
atherosclerosis, diabetes and metabolic syndrome, we hypothesized that
accelerated atherosclerosis may be linked to altered hepatic development. This
hypothesis was tested in ApoE(-/-) mice exposed to 49 ppm arsenic in utero from
gestational day (GD) 8 to term. GD18 hepatic arsenic was 1.2 µg/g in dams and
350 ng/g in fetuses. The hepatic transcriptome was evaluated by microarray
analysis to assess mRNA and microRNA abundance in control and exposed pups at
postnatal day (PND) 1 and PND70. Arsenic exposure altered postnatal
developmental trajectory of mRNA and microRNA profiles. We identified an arsenic
exposure related 51-gene signature at PND1 and PND70 with several hubs of
interaction (Hspa8, IgM and Hnf4a). Gene ontology (GO) annotation analyses
indicated that pathways for gluconeogenesis and glycolysis were suppressed in
exposed pups at PND1, and pathways for protein export, ribosome, antigen
processing and presentation, and complement and coagulation cascades were
induced by PND70. Promoter analysis of differentially-expressed transcripts
identified enriched transcription factor binding sites and clustering to common
regulatory sites. SREBP1 binding sites were identified in about 16% of PND70
differentially-expressed genes. Western blot analysis confirmed changes in the
liver at PND70 that included increases of heat shock protein 70 (Hspa8) and
active SREBP1. Plasma AST and ALT levels were increased at PND70. These results
suggest that transplacental arsenic exposure alters developmental programming in
fetal liver, leading to an enduring stress and proinflammatory response
postnatally that may contribute to early onset of atherosclerosis. Genes
containing SREBP1 binding sites also suggest pathways for diabetes mellitus and
rheumatoid arthritis, both diseases that contribute to increased cardiovascular
disease in humans. INTRODUCTION: Hypoxia and T-helper cell 1 (Th1) cytokine-driven inflammation are
key features of rheumatoid arthritis (RA) and contribute to disease pathogenesis
by promoting angiogenesis. The objective of our study was to characterise the
angiogenic gene signature of RA fibroblast-like synoviocytes (FLS) in response
to hypoxia, as well as Th1 and T-helper cell 2 (Th2) cytokines, and in
particular to dissect out effects of combined hypoxia and cytokines on hypoxia
inducible transcription factors (HIFs) and angiogenesis.
METHODS: Human angiogenesis PCR arrays were used to screen cDNA from RA FLS
exposed to hypoxia (1% oxygen) or dimethyloxalylglycine, which stabilises HIFs.
The involvement of HIF isoforms in generating the angiogenic signature of RA FLS
stimulated with hypoxia and/or cytokines was investigated using a DNA-binding
assay and RNA interference. The angiogenic potential of conditioned media from
hypoxia-treated and/or cytokine-treated RA FLS was measured using an in vitro
endothelial-based assay.
RESULTS: Expression of 12 angiogenic genes was significantly altered in RA FLS
exposed to hypoxia, and seven of these were changed by dimethyloxalylglycine,
including ephrin A3 (EFNA3), vascular endothelial growth factor (VEGF),
adipokines angiopoietin-like (ANGPTL)-4 and leptin. These four proangiogenic
genes were dependent on HIF-1 in hypoxia to various degrees: EFNA3 >ANGPTL-4
>VEGF >leptin. The Th1 cytokines TNFα and IL-1β induced HIF-1 but not HIF-2
transcription as well as activity, and this effect was additive with hypoxia. In
contrast, Th2 cytokines had no effect on HIFs. IL-1β synergised with hypoxia to
upregulate EFNA3 and VEGF in a HIF-1-dependent fashion but, despite strongly
inducing HIF-1, TNFα suppressed adipokine expression and had minimal effect on
EFNA3. Supernatants from RA FLS subjected to hypoxia and TNFα induced fewer
endothelial tubules than those from FLS subjected to TNFα or hypoxia alone,
despite high VEGF protein levels. The Th2 cytokine IL-4 strongly induced
ANGPTL-4 and angiogenesis by normoxic FLS and synergised with hypoxia to induce
further proangiogenic activity.
CONCLUSION: The present work demonstrates that Th1 cytokines in combination with
hypoxia are not sufficient to induce angiogenic activity by RA FLS despite HIF-1
activation and VEGF production. In contrast, Th2 cytokines induce angiogenic
activity in normoxia and hypoxia, despite their inability to activate HIFs,
highlighting the complex relationships between hypoxia, angiogenesis and
inflammation in RA. OBJECTIVES: Gene expression signatures can provide an unbiased view into the
molecular changes underlying biologically and medically interesting phenotypes.
We therefore initiated this study to identify signatures that would be of
utility in studying rheumatoid arthritis (RA).
METHODS: We used microarray profiling of peripheral blood mononuclear cells
(PBMCs) in 30 RA patients to assess the effect of different biologic agent
(biologics) treatments and to quantify the degree of a type-I interferon (IFN)
signature in these patients. A numeric score was derived for the quantification
step and applied to patients with RA. To further characterize the IFN response
in our cohort, we employed type-I IFN treatment of PBMCs in vitro and in
reporter assays.
RESULTS: Profiling identified a subset of RA patients with upregulation of
type-I IFN-regulated transcripts, thereby corroborating previous reports showing
RA to be heterogeneous for an IFN component. A comparison of individuals
currently untreated with a biologic with those treated with infliximab,
tocilizumab, or abatacept suggested that each biologic induces a specific gene
signature in PBMCs.
CONCLUSIONS: It is possible to observe signs of type-I IFN pathway activation in
a subset of clinically active RA patients without C-reactive protein elevation.
Furthermore, biologics-specific gene signatures in patients with RA indicate
that looking for a biologic-specific response pattern may be a potential future
tool for predicting individual patient response. OBJECTIVE: The folate antagonist methotrexate (MTX) is an anchor drug in the
treatment of rheumatoid arthritis (RA), but its mechanism of action with regard
to the impact on folate metabolism remains elusive. The aim of the present study
was to investigate the cellular pharmacologic impact of MTX on peripheral blood
cells, by comparing MTX-treated RA patients to MTX-naive RA patients and healthy
controls.
METHODS: Gene expression microarray data were used to investigate the expression
of 17 folate pathway genes by peripheral blood cells from a cohort of 25 RA
patients treated with MTX, 10 MTX-naive RA patients starting treatment with MTX,
and 15 healthy controls (test cohort). Multiplex real-time polymerase chain
reaction was used to validate the results in an independent cohort, consisting
of 151 RA patients treated with MTX, 28 MTX-naive RA patients starting treatment
with MTX, and 24 healthy controls (validation cohort).
RESULTS: Multiple folate metabolism-related genes were consistently and
significantly altered between the 3 groups in both cohorts. Concurrent with
evidence of an immune-activation gene signature in MTX-naive RA patients,
significant up-regulation of the folate-metabolizing enzymes γ-glutamyl
hydrolase and dihydrofolate reductase, as well as the MTX/folate efflux
transporters ABCC2 and ABCC5, was observed in the MTX-naive RA group compared to
healthy controls. Strikingly, MTX treatment of RA patients normalized these
differential gene expression levels to the levels observed in healthy controls.
CONCLUSION: These results suggest that under inflammatory conditions, basal
folate metabolism in the peripheral blood cells of RA patients is markedly
up-regulated, and treatment with MTX restores folate metabolism to normal
levels. Identification of this novel gene signature provides insight into the
mechanism of action of MTX, thus paving the way for development of novel folate
metabolism-targeted therapies. INTRODUCTION: Rheumatoid arthritis (RA) is a complex and clinically
heterogeneous autoimmune disease. Currently, the relationship between pathogenic
molecular drivers of disease in RA and therapeutic response is poorly
understood.
METHODS: We analyzed synovial tissue samples from two RA cohorts of 49 and 20
patients using a combination of global gene expression, histologic and cellular
analyses, and analysis of gene expression data from two further publicly
available RA cohorts. To identify candidate serum biomarkers that correspond to
differential synovial biology and clinical response to targeted therapies, we
performed pre-treatment biomarker analysis compared with therapeutic outcome at
week 24 in serum samples from 198 patients from the ADACTA (ADalimumab ACTemrA)
phase 4 trial of tocilizumab (anti-IL-6R) monotherapy versus adalimumab
(anti-TNFα) monotherapy.
RESULTS: We documented evidence for four major phenotypes of RA synovium -
lymphoid, myeloid, low inflammatory, and fibroid - each with distinct underlying
gene expression signatures. We observed that baseline synovial myeloid, but not
lymphoid, gene signature expression was higher in patients with good compared
with poor European league against rheumatism (EULAR) clinical response to
anti-TNFα therapy at week 16 (P =0.011). We observed that high baseline serum
soluble intercellular adhesion molecule 1 (sICAM1), associated with the myeloid
phenotype, and high serum C-X-C motif chemokine 13 (CXCL13), associated with the
lymphoid phenotype, had differential relationships with clinical response to
anti-TNFα compared with anti-IL6R treatment. sICAM1-high/CXCL13-low patients
showed the highest week 24 American College of Rheumatology (ACR) 50 response
rate to anti-TNFα treatment as compared with sICAM1-low/CXCL13-high patients
(42% versus 13%, respectively, P =0.05) while anti-IL-6R patients showed the
opposite relationship with these biomarker subgroups (ACR50 20% versus 69%, P
=0.004).
CONCLUSIONS: These data demonstrate that underlying molecular and cellular
heterogeneity in RA impacts clinical outcome to therapies targeting different
biological pathways, with patients with the myeloid phenotype exhibiting the
most robust response to anti-TNFα. These data suggest a path to identify and
validate serum biomarkers that predict response to targeted therapies in
rheumatoid arthritis and possibly other autoimmune diseases.
TRIAL REGISTRATION: ClinicalTrials.gov NCT01119859 Rheumatoid arthritis (RA) is a chronic inflammatory disease whose pathogenesis
and severity correlates with the presence of macrophage-derived pro-inflammatory
cytokines within the inflamed synovium. Macrophage-derived cytokines fuel the
pathological processes in RA and are targets of clinically successful therapies.
However, although macrophage polarization determines cytokine production, the
polarization state of macrophages in RA joints remains poorly defined. To
dissect the molecular basis for the tissue-damaging effects of macrophages in RA
joints, we undertook the phenotypic and transcriptomic characterization of ex
vivo isolated CD14(+) RA synovial fluid (RA-SF) macrophages. Flow cytometry and
gene profiling indicated that RA-SF macrophages express pro-inflammatory
polarization markers (MMP12, EGLN3, CCR2), lack expression of markers associated
with homeostatic and anti-inflammatory polarization (IGF1, HTR2B) and exhibit a
transcriptomic profile that resembles the activin A-dependent gene signature of
pro-inflammatory in vitro-generated macrophages. In fact, high levels of
Smad-activating activin A were found in RA-SF and, accordingly, the Smad
signalling pathway was activated in ex vivo-isolated RA-SF macrophages. In vitro
experiments on monocytes and macrophages indicated that RA-SF promoted the
acquisition of pro-inflammatory markers (INHBA, MMP12, EGLN3, CCR2) but led to a
significant reduction in the expression of genes associated with homeostasis and
inflammation resolution (FOLR2, SERPINB2, IGF1, CD36), thus confirming the
pro-inflammatory polarization ability of RA-SF. Importantly, the
macrophage-polarizing ability of RA-SF was inhibited by an anti-activin
A-neutralizing antibody, thus demonstrating that activin A mediates the
pro-inflammatory macrophage-polarizing ability of RA-SF. Moreover, and in line
with these findings, multicolour immunofluorescence evidenced that macrophages
within RA synovial membranes (RA-SM) also express pro-inflammatory polarization
markers whose expression is activin A-dependent. Altogether, our results
demonstrate that macrophages from RA synovial fluids and membranes exhibit an
MMP12(+) EGLN3(+) CCR2(+) pro-inflammatory polarization state whose acquisition
is partly dependent on activin A from the synovial fluid. Approximately 30% of rheumatoid arthritis patients achieve inadequate response
to anti-TNF biologics. Attempts to identify molecular biomarkers predicting
response have met with mixed success. This may be attributable, in part, to the
variable and subjective disease assessment endpoints with large placebo effects
typically used to classify patient response. Sixty-one patients with active RA
despite methotrexate treatment, and with MRI-documented synovitis, were
randomized to receive infliximab or placebo. Blood was collected at baseline and
genome-wide transcription in whole blood was measured using microarrays. The
primary endpoint in this study was determined by measuring the transfer rate
constant (Ktrans) of a gadolinium-based contrast agent from plasma to synovium
using MRI. Secondary endpoints included repeated clinical assessments with
DAS28(CRP), and assessments of osteitis and synovitis by the RAMRIS method.
Infliximab showed greater decrease from baseline in DCE-MRI Ktrans of wrist and
MCP at all visits compared with placebo (P<0.001). Statistical analysis was
performed to identify genes associated with treatment-specific 14-week change in
Ktrans. The 256 genes identified were used to derive a gene signature score by
averaging their log expression within each patient. The resulting score
correlated with improvement of Ktrans in infliximab-treated patients and with
deterioration of Ktrans in placebo-treated subjects. Poor responders showed high
expression of activated B-cell genes whereas good responders exhibited a gene
expression pattern consistent with mobilization of neutrophils and monocytes and
high levels of reticulated platelets. This gene signature was significantly
associated with clinical response in two previously published whole blood gene
expression studies using anti-TNF therapies. These data provide support for the
hypothesis that anti-TNF inadequate responders comprise a distinct molecular
subtype of RA characterized by differences in pre-treatment blood mRNA
expression. They also highlight the importance of placebo controls and robust,
objective endpoints in biomarker discovery.
TRIAL REGISTRATION: ClinicalTrials.gov NCT01313520. |
Which NGS alignment software implement the Burrows-Wheeler Transform? | The most widely used software belong to the family of the Burrows-Wheeler Aligner (BWA) and its variants for local alignment BWASW, map reduce BWASW-PMR and multi-threaded implementation BWA-MT. Other approaches include Bowtie, SOAP2, BWBBLE, SOAP2 and FANSe2. | MOTIVATION: The enormous amount of short reads generated by the new DNA
sequencing technologies call for the development of fast and accurate read
alignment programs. A first generation of hash table-based methods has been
developed, including MAQ, which is accurate, feature rich and fast enough to
align short reads from a single individual. However, MAQ does not support gapped
alignment for single-end reads, which makes it unsuitable for alignment of
longer reads where indels may occur frequently. The speed of MAQ is also a
concern when the alignment is scaled up to the resequencing of hundreds of
individuals.
RESULTS: We implemented Burrows-Wheeler Alignment tool (BWA), a new read
alignment package that is based on backward search with Burrows-Wheeler
Transform (BWT), to efficiently align short sequencing reads against a large
reference sequence such as the human genome, allowing mismatches and gaps. BWA
supports both base space reads, e.g. from Illumina sequencing machines, and
color space reads from AB SOLiD machines. Evaluations on both simulated and real
data suggest that BWA is approximately 10-20x faster than MAQ, while achieving
similar accuracy. In addition, BWA outputs alignment in the new standard SAM
(Sequence Alignment/Map) format. Variant calling and other downstream analyses
after the alignment can be achieved with the open source SAMtools software
package.
AVAILABILITY: http://maq.sourceforge.net. MOTIVATION: Many programs for aligning short sequencing reads to a reference
genome have been developed in the last 2 years. Most of them are very efficient
for short reads but inefficient or not applicable for reads >200 bp because the
algorithms are heavily and specifically tuned for short queries with low
sequencing error rate. However, some sequencing platforms already produce longer
reads and others are expected to become available soon. For longer reads,
hashing-based software such as BLAT and SSAHA2 remain the only choices.
Nonetheless, these methods are substantially slower than short-read aligners in
terms of aligned bases per unit time.
RESULTS: We designed and implemented a new algorithm, Burrows-Wheeler Aligner's
Smith-Waterman Alignment (BWA-SW), to align long sequences up to 1 Mb against a
large sequence database (e.g. the human genome) with a few gigabytes of memory.
The algorithm is as accurate as SSAHA2, more accurate than BLAT, and is several
to tens of times faster than both.
AVAILABILITY: http://bio-bwa.sourceforge.net SUMMARY: The increasing availability of high-throughput sequencing technologies
has led to thousands of human genomes having been sequenced in the past years.
Efforts such as the 1000 Genomes Project further add to the availability of
human genome variation data. However, to date, there is no method that can map
reads of a newly sequenced human genome to a large collection of genomes.
Instead, methods rely on aligning reads to a single reference genome. This leads
to inherent biases and lower accuracy. To tackle this problem, a new alignment
tool BWBBLE is introduced in this article. We (i) introduce a new compressed
representation of a collection of genomes, which explicitly tackles the genomic
variation observed at every position, and (ii) design a new alignment algorithm
based on the Burrows-Wheeler transform that maps short reads from a newly
sequenced genome to an arbitrary collection of two or more (up to millions of)
genomes with high accuracy and no inherent bias to one specific genome.
AVAILABILITY: http://viq854.github.com/bwbble. Due to next-generation sequencing (NGS) technology, genome sequencing is able to
process much more data at low cost. In NGS data analysis, the mapping of
sequences into a reference genome takes the largest amount of time to process.
Although the Burrows-Wheeler Aligner (BWA) tool is one of the most widely used
open-source software tools to align read sequences, it is still limited in that
it does not fully support multi-thread mechanisms during the alignment steps. In
this paper, we propose a BWA-MT tool, evolved from BWA but supporting
multi-thread computation, designed to fully utilize the underlying multi-core
architecture of computing resources. By using multi-thread computation, BWA-MT
can significantly shorten the time needed to generate an alignment for
single-end read sequences. Meanwhile, it generates an identical Sequence
Alignment Map (SAM) result file as BWA. To evaluate BWA-MT, we use an evaluation
system equipped with twelve cores and 32 GB memory. As a workload, we used the
hg19 human genome reference sequence and various numbers of read sequences from
1M to 40M. In our evaluation, BWA-MT displays up to 3.7 times faster performance
and generates an identical SAM result file to BWA. Although the increased speed
might be dependent on computing resources, we confirm that BWA-MT is highly
efficient and effective. |
Is intraoperative radiotherapy used for treatment of glioblastoma? | Yes, intraoperative radiotherapy (IORT) is being used for treatment of glioblastoma. IORT combined with extensive tumor removal has an acceptable toxicity in previously irradiated patients and can be effective for selected recurrent malignant brain tumors. | An intraoperative remote afterloading endocurietherapy technique with
high-activity 60Co for the treatment of glioblastoma multiforme is described.
The technique can be used for initial management of the unresectable tumor or
for retreatment of patients with recurrent tumor who have been treated
previously with surgery and postoperative radiotherapy. Neither intraoperative
nor postoperative complications were encountered in our treatment of 11 patients
in this Phase I toxicity study. We studied the effects of increased-dose radiation therapy in terms of survival
time and improvement in the quality of life in 50 glioblastoma patients with
minimal residual tumors. 1) Intraoperative radiotherapy ( IOR , 1,000-2,000 rad)
was applied in 13 cases; the 2-year survival was 41.6%. However, in 9 patients
who had undergone macroscopic total removal the 2-year survival rate was 68.6%.
2) Wide resection with necrotomy after conventional external irradiation was
used in 9 cases and conformation irradiation was added; their 2-year survival
was 44.4%. 3) In 22 patients who received only conventional irradiation
following surgery, the 2-year survival was 7.5%. Intraoperative radiotherapy (IORT) was performed in 20 of 36 patients with
glioma; 11 glioblastomas, 7 maligt astrocytomas, 2 benign astrocytomas.
Twenty or 25 Gy of irradiation was delivered in a single fraction
intraoperatively, followed by external beam irradiation. The electron beam
energy was selected so that the 80% isodose line fell at 2 or 3 cm below the
residual tumor surface. Median survival time of IORT group was 14 months and
that of the control group was 10 months. Difference of survival curve was
significant. There were 6 incidences of complication caused by IORT; 1
radionecrosis, 1 convulsion, 1 abscess, and 3 severe brain edemas. IORT is
suited for the treatment of maligt gliomas. BACKGROUND: Even after surgery and radiotherapy, maligt gliomas still have a
poor prognosis. The authors report on their experience with IORT in 71 patients.
PATIENTS AND METHODS: From May 1992 to February 2004, 71 patients with maligt
gliomas were treated with IORT. 26 patients suffered from grade III gliomas, 45
patients from glioblastomas (GBM). IORT was carried out using a standard
electron tube and 9- to 18-MeV electrons. 52/71 patients who were primarily
treated received 20 Gy IORT + 60 Gy postoperative radiotherapy, 19/71 patients
with recurrences only received IORT (20-25 Gy).
RESULTS: The complication rates were 1.4% for wound infections and 5.6% for
hemorrhage. Median disease-specific survival amounted to 14.9 months (gliomas
III) and 14.2 months (GBM). The 2-year survival rates amounted to 26.9% (gliomas
III) and 6.8% (GBM; p = 0.0296). Total versus subtotal resection had no
significant influence on survival (p = 0.0741), nor had age, sex, tumor site,
performance status, size, primary versus recurrence, and radiation dose. A
comparison to a conventionally treated patient group did not show a significant
survival improvement. 3 months after treatment, initial symptoms had improved in
59% (hemiparesis), 50% (aphasia), 50% (hemianopsia), and 60% (convulsions).
CONCLUSION: IORT has been shown to be feasible; perioperative complication rates
were not increased. Survival was generally not improved compared to a historical
control group. Recurrences achieved the same survival as primary tumors, and GBM
also had a slightly increased survival, thus being possible indications for
IORT. BACKGROUND: The study investigated if intraoperative use of carmustine wafers,
particularly in combination with Stupp regimen, is a viable and safe first-line
treatment option of glioblastomas.
METHODS: Eighty-three consecutive adult patients (50 men; mean age 60 years)
with newly diagnosed supratentorial primary glioblastomas that underwent
surgical resection with intraoperative carmustine wafers implantation (n = 7.1 ±
1.7) were retrospectively studied.
RESULTS: The median overall survival (OS) was 15.8 months with 56 patients dying
over the course of the study. There was no significant association between the
number of implanted carmustine wafers and complication rates (four surgical site
infections, one death). The OS was significantly longer in Stupp regimen
patients (19.5 months) as compared with patients with other postoperative
treatments (13 months; p = 0.002). In addition patients with eight or more
implanted carmustine wafers survived longer (24.5 months) than patients with
seven or less implanted wafers (13 months; p = 0.021). Finally, regardless of
the number of carmustine wafers, median OS was significantly longer in patients
with a subtotal or total resection (21.5 months) than in patients with a partial
resection (13 months; p = 0.011).
CONCLUSIONS: The intraoperative use of carmustine wafers in combination with
Stupp regimen is a viable first-line treatment option of glioblastomas. The
prognostic value of this treatment association should be evaluated in a
multicenter trial, ideally in a randomized and placebo-controlled one. Glioblastoma is the most common and aggressive adult primary brain cancer.
Despite multimodal therapy, it is associated with a survival of less than two
years. Greater than 85% of recurrences occur within the original area of surgery
and radiotherapy, suggesting a potential for improved local treatments. In
addition to cancer cell invasion beyond surgical margins, a plethora of
postinjury pro-proliferative stimuli are released from local healing brain,
which both protect and nourish remaining cancer cells. This review compiles
preclinical and clinical evidence for a dedicated treatment of both residual
cancer cells and regional microenvironment using intraoperative radiotherapy
(IORT). |
Which server is used for generating modes of pseudo components of DNA, RNA and protein sequences? | Pse-in-One is a web server for generating various modes of pseudo components of DNA, RNA, and protein sequences. It can, through its 28 different modes, generate nearly all the possible feature vectors for DNA, RNA and protein sequences. Particularly, it can also generate those feature vectors with the properties defined by users themselves. These feature vectors can be easily combined with machine-learning algorithms to develop computational predictors and analysis methods for various tasks in bioinformatics and system biology. | With the avalanche of biological sequences generated in the post-genomic age,
one of the most challenging problems in computational biology is how to
effectively formulate the sequence of a biological sample (such as DNA, RNA or
protein) with a discrete model or a vector that can effectively reflect its
sequence pattern information or capture its key features concerned. Although
several web servers and stand-alone tools were developed to address this
problem, all these tools, however, can only handle one type of samples.
Furthermore, the number of their built-in properties is limited, and hence it is
often difficult for users to formulate the biological sequences according to
their desired features or properties. In this article, with a much larger number
of built-in properties, we are to propose a much more flexible web server called
Pse-in-One (http://bioinformatics.hitsz.edu.cn/Pse-in-One/), which can, through
its 28 different modes, generate nearly all the possible feature vectors for
DNA, RNA and protein sequences. Particularly, it can also generate those feature
vectors with the properties defined by users themselves. These feature vectors
can be easily combined with machine-learning algorithms to develop computational
predictors and analysis methods for various tasks in bioinformatics and system
biology. It is anticipated that the Pse-in-One web server will become a very
useful tool in computational proteomics, genomics, as well as biological
sequence analysis. Moreover, to maximize users' convenience, its stand-alone
version can also be downloaded from
http://bioinformatics.hitsz.edu.cn/Pse-in-One/download/, and directly run on
Windows, Linux, Unix and Mac OS. |
What is the link between TB (Turbeculosis) infection and TNFa inhibition? | The occurrence of tuberculosis (TB) in patients treated with immunosuppressive drugs (ISD) is an old problem that has been highlighted by cases occurring in patients using anti-TNFalpha drugs. | TNFalpha plays a pivotal role not only in the inflammatory process but also in
the normal response against pathogens and therefore, interfering with this
cytokine may increase the risk of infection. TNFalpha antagonists are commonly
used in daily clinical practice for the treatment of inflammatory rheumatic
diseases including rheumatoid arthritis, ankylosing spondylitis, psoriatic
arthritis and juvenile idiopathic arthritis since the beginning of 2000. The
spectrum of pathogens giving infectious disease in patients under anti-TNFalpha
therapies ranges from common bacteria to more opportunistic organisms such as
Mycobacterium tuberculosis. The infections which were described with TNFalpha
inhibitors may have a benign course or may be a serious, life threatening
disease, and may be localized or disseminated. These TNFalpha inhibitors related
infections were described in the randomized clinical trials, and were then
declared to post-marketing surveillance systems and special registries.
Tuberculosis (TB) is the most frequent opportunistic infection which has been
reported with TNFalpha antagonists and the highest risk appears to be associated
with infliximab, and at a lesser extent with etanercept. Currently available
data and recent patents on the risk of TB with adalimumab are not sufficient to
conclude, but TB cases were also reported with this agent. The description of TB
infections with TNFalpha inhibitors led to the establishment of new guidelines
for screening patients at high risk of developing TB. These data highlight the
importance of post-marketing surveillance and special registries for accurately
evaluating the safety profile and particularly the infectious risk of this very
effective class of drug in inflammatory rheumatic diseases. OBJECTIVE: To compare the performance of two interferon gamma release assays
(IGRAs) and conventional screening tests in patients with inflammatory arthritis
undergoing screening for latent tuberculosis infection (LTBI) before treatment
with anti-tumour necrosis factor alpha (anti-TNFalpha) compounds.
METHODS: Successive patients were subjected to conventional LTBI screening,
including a tuberculin skin test (TST). The T-SPOT.TB test was performed on all
patients and the QuantiFERON-TB Gold test was performed on a large subset. The
results of the IGRAs were compared with the results of conventional screening
tests.
RESULTS: A total 150 patients were evaluated. The majority (57.9%) had
rheumatoid arthritis. Previous vaccination with Bacille Calmette-Guerin was
confirmed in 82% of patients. No patient had received prior anti-TB treatment. A
total of 57 patients (38.0%) had at least one positive conventional risk factor.
In contrast, an unequivocally positive T-SPOT.TB test was seen in only 14/143
(9.8%). There was 98.2% agreement between the two IGRAs. Statistically
significant associations were found between each of the IGRAs and both TST and
risk history, but not chest x-ray (CXR). A positive IGRA result was
significantly associated with increased age. TB was not reactivated in any
patient during the follow-up period.
INTERPRETATION: This study suggests that IGRAs may be useful when screening for
LTBI before anti-TNFalpha therapy in patients with immune-mediated inflammatory
diseases. The observations reported here also highlight the inadequate
performance of CXR as a marker of LTBI. Author information:
(1)Department of Internal Medicine, University Hospitals Leuven, Herestraat 49,
B-3000 Leuven, Belgium.
(2)Department of Infectious Diseases, University Hospitals Leuven, Herestraat
49, B-3000 Leuven, Belgium.
(3)Department of Respiratory Division, University Hospitals Leuven, Herestraat
49, B-3000 Leuven, Belgium.
(4)Department of Radiology, University Hospitals Leuven, Herestraat 49, B-3000
Leuven, Belgium.
(5)Department of Gastroenterology, University Hospitals Leuven, Herestraat 49,
B-3000 Leuven, Belgium.
(6)Department of Gastroenterology, University Hospitals Leuven, Herestraat 49,
B-3000 Leuven, Belgium. Electronic address: [email protected]. The use of TNFalpha blockers is associated with reactivation of tuberculosis
(TB). The previous guidelines of the Israeli Association of Rheumatology were
based on the tuberculin skin test (TST), chest X ray and a questionnaire on
possible previous exposure to TB. The growing use of Interferon-gamma released
assay (IGRA) has prompted the need for an update to these guidelines. All
patients who are candidates to receive TNFalpha blockers should be screened for
active or Latent tuberculosis. The screening includes: Tuberculin Skin Test
(TST), interferon-gamma release assays (IGRA), chest X-ray and a questionnaire
about possible exposure to tuberculosis. TST > or = 10 mm is considered
positive; TST < or = 5 is negative; in case of TST = 0, a 2-step screening is
recommended. If TST is > or = 5 mm but < 10 mm or in heavy immunosuppressed
patients with TST = 0, an IGRA test should be performed and the diagnosis of
latent TB taken accordingly. If the IGRA test is indeterminate, the decision
should be taken based on the TST and patient's characteristics. Patients with a
TST less than 5 mm. should be questioned about prior exposure to tuberculosis.
Latent tuberculosis should be treated with a 9 month course of isoniazid (300
mg/d) or a 4 month course of rifampicin (600 mg/d) or for 3 months with a
combination of 300 mg. isoniazid and 600 mg. rifampicin daily. The committee
recommends postponing treatment with TNFalpha blockers until completion of
anti-tuberculosis therapy. If the clinical condition requires the urgent use of
TNFalpha blockers, these may be initiated one month after starting treatment for
latent tuberculosis. |
Which class of genes are mutated in Diamond Blackfan Anemia patients? | Diamond-Blackfan Anemia (DBA) is characterized by a defect of erythroid progenitors and, clinically, by anemia and malformations. Diamond Blackfan anemia (DBA) is an inherited erythroblastopenia associated with mutations in at least 8 different ribosomal protein genes. Diamond-Blackfan anemia (DBA) is a rare congenital disease affecting erythroid precursor differentiation. Diamond-Blackfan anemia (DBA) is a congenital disease characterized by defective erythroid progenitor maturation and physical malformations. | The gene encoding ribosomal protein S19 (RPS19) has been shown to be mutated in
25% of the patients affected by Diamond-Blackfan anemia (DBA), a congenital
erythroblastopenia. As the role of RPS19 in erythropoiesis is still to be
defined, we performed studies on RPS19 expression during terminal erythroid
differentiation. Comparative analysis of the genomic sequences of human and
mouse RPS19 genes enabled the identification of 4 conserved sequence elements in
the 5' region. Characterization of transcriptional elements allowed the
identification of the promoter in the human RPS19 gene and the localization of a
strong regulatory element in the third conserved sequence element. By Northern
blot and Western blot analyses of murine splenic erythroblasts infected with the
anemia-inducing strain Friend virus (FAV cells), RPS19 mRNA and protein
expression were shown to decrease during terminal erythroid differentiation. We
anticipate that these findings will contribute to further development of our
understanding of the contribution of RPS19 to erythropoiesis. Ribosomal protein S19 (RPS19) is frequently mutated in Diamond-Blackfan anemia
(DBA), a rare congenital hypoplastic anemia. Recent studies have shown that
RPS19 expression decreases during terminal erythroid differentiation. Currently
no information is available on the subcellular localization of normal RPS19 and
the potential effects of various RPS19 mutations on cellular localization. In
the present study, using wild-type and mutant RPS19 cDNA, we explored the
subcellular distribution of normal and mutant proteins in a fibroblast cell line
(Cos-7 cells). RPS19 was detected primarily in the nucleus, and more
specifically in the nucleoli, where RPS19 colocalized with the nucleolar protein
nucleolin. Using various N-terminal and C-terminal deletion constructs, we
identified 2 nucleolar localization signals (NoSs) in RPS19: the first
comprising amino acids Met1 to Arg16 in the NH2-terminus and the second
comprising Gly120 to Asn142 in the COOH-terminus. Importantly, 2 mutations
identified in DBA patients, Val15Phe and Gly127Gln, each of which localized to 1
of the 2 NoS, failed to localize RPS19 to the nucleolus. In addition to their
mislocalization, there was a dramatic decrease in the expression of the 2 mutant
proteins compared to the wild type. This decrease in protein expression was
specific for the mutant RPS19, since expression of other proteins was normal.
The present findings enable us to document the nucleolar localization signals in
RPS19 and help define the phenotypic consequences of some mutations in RPS19 in
DBA. Diamond-Blackfan anemia (DBA) typically presents with red blood cell aplasia
that usually manifests in the first year of life. The only gene currently known
to be mutated in DBA encodes ribosomal protein S19 (RPS19). Previous studies
have shown that the yeast RPS19 protein is required for a specific step in the
maturation of 40S ribosomal subunits. Our objective here was to determine
whether the human RPS19 protein functions at a similar step in 40S subunit
maturation. Studies where RPS19 expression is reduced by siRNA in the
hematopoietic cell line, TF-1, show that human RPS19 is also required for a
specific step in the maturation of 40S ribosomal subunits. This maturation
defect can be monitored by studying rRNA-processing intermediates along the
ribosome synthesis pathway. Analysis of these intermediates in CD34- cells from
the bone marrow of patients with DBA harboring mutations in RPS19 revealed a
pre-rRNA-processing defect similar to that observed in TF-1 cells where RPS19
expression was reduced. This defect was observed to a lesser extent in CD34+
cells from patients with DBA who have mutations in RPS19. Diamond-Blackfan anemia (DBA) is a rare congenital red-cell aplasia
characterized by anemia, bone-marrow erythroblastopenia, and congenital
anomalies and is associated with heterozygous mutations in the ribosomal protein
(RP) S19 gene (RPS19) in approximately 25% of probands. We report identification
of de novo nonsense and splice-site mutations in another RP, RPS24 (encoded by
RPS24 [10q22-q23]) in approximately 2% of RPS19 mutation-negative probands. This
finding strongly suggests that DBA is a disorder of ribosome synthesis and that
mutations in other RP or associated genes that lead to disrupted ribosomal
biogenesis and/or function may also cause DBA. Diamond-Blackfan anemia (DBA) is a congenital erythroid aplasia characterized as
a normochromic macrocytic anemia with a selective deficiency in red blood cell
precursors in otherwise normocellular bone marrow. In 40% of DBA patients,
various physical anomalies are also present. Currently two genes are associated
with the DBA phenotype--the ribosomal protein (RP) S19 mutated in 25% of DBA
patients and RPS24 mutated in approximately 1.4% of DBA patients. Here we report
the identification of a mutation in yet another ribosomal protein, RPS17. The
mutation affects the translation initiation start codon, changing T to G
(c.2T>G), thus eliminating the natural start of RPS17 protein biosynthesis. RNA
analysis revealed that the mutated allele was expressed, and the next downstream
start codon located at position +158 should give rise to a short peptide of only
four amino acids (Met-Ser-Arg-Ile). The mutation arose de novo, since all
healthy family members carry the wild-type alleles. The identification of a
mutation in the third RP of the small ribosomal subunit in DBA patients further
supports the theory that impaired translation may be the main cause of DBA
pathogenesis. Diamond-Blackfan anemia (DBA) is a rare congenital disease affecting erythroid
precursor differentiation. DBA is emerging as a paradigm for a new class of
pathologies potentially linked to disorders in ribosome biogenesis. Three genes
encoding ribosomal proteins have been associated to DBA: after RPS19, mutations
in genes RPS24 and RPS17 were recently identified in a fraction of the patients.
Here, we show that cells from patients carrying mutations in RPS24 have
defective pre-rRNA maturation, as in the case of RPS19 mutations. However, in
contrast to RPS19 involvement in the maturation of the internal transcribed
spacer 1, RPS24 is required for processing of the 5' external transcribed
spacer. Remarkably, epistasis experiments with small interfering RNAs indicate
that the functions of RPS19 and RPS24 in pre-rRNA processing are connected.
Resolution of the crystal structure of RPS24e from the archeon Pyroccocus abyssi
reveals domains of RPS24 potentially involved in interactions with
pre-ribosomes. Based on these data, we discuss the impact of RPS24 mutations and
speculate that RPS19 and RPS24 cooperate at a particular stage of ribosome
biogenesis connected to a cell cycle checkpoint, thus affecting differentiation
of erythroid precursors as well as developmental processes. Diamond-Blackfan anemia (DBA) is an inherited bone marrow failure syndrome
characterized by anemia, congenital abnormalities, and cancer predisposition.
Small ribosomal subunit genes RPS19, RPS24, and RPS17 are mutated in
approximately one-third of patients. We used a candidate gene strategy combining
high-resolution genomic mapping and gene expression microarray in the analysis
of 2 DBA patients with chromosome 3q deletions to identify RPL35A as a potential
DBA gene. Sequence analysis of a cohort of DBA probands confirmed involvement
RPL35A in DBA. shRNA inhibition shows that Rpl35a is essential for maturation of
28S and 5.8S rRNAs, 60S subunit biogenesis, normal proliferation, and cell
survival. Analysis of pre-rRNA processing in primary DBA lymphoblastoid cell
lines demonstrated similar alterations of large ribosomal subunit rRNA in both
RPL35A-mutated and some RPL35A wild-type patients, suggesting additional large
ribosomal subunit gene defects are likely present in some cases of DBA. These
data demonstrate that alterations of large ribosomal subunit proteins cause DBA
and support the hypothesis that DBA is primarily the result of altered ribosomal
function. The results also establish that haploinsufficiency of large ribosomal
subunit proteins contributes to bone marrow failure and potentially cancer
predisposition. BACKGROUND: Mutations in the ribosomal protein S19 gene (RPS19) have been found
in 25% of patients with Diamond-Blackfan anemia, a rare syndrome of congenital
bone marrow failure characterized by erythroblastopenia and various
malformations. Mechanistic understanding of the role of RPS19 in normal
erythropoiesis and in the Diamond-Blackfan anemia defect is still poor. However,
defective ribosome biogenesis and, in particular, impaired 18S ribosomal RNA
maturation have been documented in association with various identified RPS19
mutations. Recently, new genes, all encoding ribosomal proteins, have been found
to be mutated in Diamond-Blackfan anemia, adding further support to the concept
that ribosome biogenesis plays an important role in regulating erythropoiesis.
We previously showed variability in the levels of expression and subcellular
localization of a subset of RPS19 mutant proteins.
DESIGN AND METHODS: To define the mechanistic basis for this variability better,
we studied a large number of mutant proteins and characterized both RPS19
expression level using a specific antibody against RPS19 and RPS19 subcellular
localization after transfection of Cos-7 cells with various green fluorescent
protein-RPS19 mutants. To investigate the role of the proteasome in RPS19
degradation, we examined the effect of various proteasome inhibitors, namely
lactacystin, MG132, and bortezomib on RPS19 expression and subcellular
localization
RESULTS: We found two distinct classes of RPS19 protein defects in
Diamond-Blackfan anemia based on the stability of the mutant proteins: (i)
slightly decreased to normal levels of expression and normal nucleolar
localization and (ii) markedly deficient expression and failure to localize to
the nucleolus. All the proteasome inhibitors tested were able to restore the
expression levels and normal subcellular localization of several unstable mutant
proteins.
CONCLUSIONS: Our findings demonstrate an important role for the proteasomal
degradation pathway in regulating the expression levels and nucleolar
localization of certain mutant RPS19 proteins in Diamond-Blackfan anemia. Mutations in ribosomal proteins RPS19, RPS24 and RPS17 have been reported in
Diamond-Blackfan Anemia (DBA), an autosomal domit disease characterised by
pure red cell aplasia. DBA is the prototype of ribosomapathies: a protein
synthesis defect in a tissue with a high cellular turnover is considered the
cause of the erythroid progenitor failure. We have created the Diamond-Blackfan
Anemia mutation database to curate and record DBA gene mutations, together with
their functional consequences and clinical phenotypes. This locus-specific
resource is open to future submissions and is available online
(http://www.dbagenes.unito.it). It is founded on the Leiden Open (source)
Variation Database (LOVD) system and includes data from sequence and structure
analysis tools, genomic database resources and published reports. It lists all
identified variants and background genomic information. Phenotypic data are
accessed by selecting a particular mutation. The database includes 219 unique
variants of which 86 are disease-causing mutations. The database will be
supplemented with other DBA genes as soon as they are reported and their
mutations are identified and it should be of assistance to clinicians and
investigators involved in DBA research and care. Diamond-Blackfan anemia (DBA) is a congenital red blood cell aplasia that is
usually diagnosed during early infancy. Apart from defects in red blood cell
maturation, the disorder is also associated with various physical anomalies in
40% of patients. Mutations in the ribosomal protein (RP) S19 are found in 25% of
patients, while mutations in other proteins of the small ribosomal
subunit--RPS17 and RPS24--have been found in a fraction of patients. Recently,
mutations in RPL5, RPL11, and RPL35a of the large ribosomal subunit have also
been reported in several DBA patients. Here, we present the identification of
mutations in the RPL5 and RPL11 genes in patients from the Czech DBA Registry.
Mutations in RPL5 were identified in eight patients from 6 out of 28 families
(21.4%), and mutations in RPL11 in two patients from 2 out of 28 families
(7.1%). Interestingly, all 10 patients with either an RPL5 or RPL11 mutation
exhibited one or more physical anomalies; specifically, thumb anomalies (flat
thenar) were always present, while no such anomaly was observed in seven
patients with an RPS19 mutation. Moreover, 9 out of 10 patients with either an
RPL5 or RPL11 mutation were born small for gestational age (SGA) compared to 3
out of 7 patients from the RPS19-mutated group. These observations may suggest
that mutations, at least in RPL5, seem to generally have more profound impact on
fetal development than mutations in RPS19. Since RPL5 and RPL11, together with
RPL23, are also involved in the MDM2-mediated p53 pathway regulation, we also
screened the RPL23 gene for mutations; however, no mutations were identified. Diamond-Blackfan anemia (DBA), an inherited bone marrow failure syndrome
characterized by anemia that usually presents before the first birthday or in
early childhood, is associated with birth defects and an increased risk of
cancer. Although anemia is the most prominent feature of DBA, the disease is
also characterized by growth retardation and congenital malformations, in
particular craniofacial, upper limb, heart, and urinary system defects that are
present in approximately 30%-50% of patients. DBA has been associated with
mutations in seven ribosomal protein (RP) genes, RPS19, RPS24, RPS17, RPL35A,
RPL5, RPL11, and RPS7, in about 43% of patients. To continue our large-scale
screen of RP genes in a DBA population, we sequenced 35 ribosomal protein genes,
RPL15, RPL24, RPL29, RPL32, RPL34, RPL9, RPL37, RPS14, RPS23, RPL10A, RPS10,
RPS12, RPS18, RPL30, RPS20, RPL12, RPL7A, RPS6, RPL27A, RPLP2, RPS25, RPS3,
RPL41, RPL6, RPLP0, RPS26, RPL21, RPL36AL, RPS29, RPL4, RPLP1, RPL13, RPS15A,
RPS2, and RPL38, in our DBA patient cohort of 117 probands. We identified three
distinct mutations of RPS10 in five probands and nine distinct mutations of
RPS26 in 12 probands. Pre-rRNA analysis in lymphoblastoid cells from patients
bearing mutations in RPS10 and RPS26 showed elevated levels of 18S-E pre-rRNA.
This accumulation is consistent with the phenotype observed in HeLa cells after
knockdown of RPS10 or RPS26 expression with siRNAs, which indicates that
mutations in the RPS10 and RPS26 genes in DBA patients affect the function of
the proteins in rRNA processing. BACKGROUND: Diamond-Blackfan anemia is a rare, clinically heterogeneous,
congenital red cell aplasia: 40% of patients have congenital abnormalities.
Recent studies have shown that in western countries, the disease is associated
with heterozygous mutations in the ribosomal protein (RP) genes in about 50% of
patients. There have been no studies to determine the incidence of these
mutations in Asian patients with Diamond-Blackfan anemia.
DESIGN AND METHODS: We screened 49 Japanese patients with Diamond-Blackfan
anemia (45 probands) for mutations in the six known genes associated with
Diamond-Blackfan anemia: RPS19, RPS24, RPS17, RPL5, RPL11, and RPL35A. RPS14 was
also examined due to its implied involvement in 5q- syndrome.
RESULTS: Mutations in RPS19, RPL5, RPL11 and RPS17 were identified in five,
four, two and one of the probands, respectively. In total, 12 (27%) of the
Japanese Diamond-Blackfan anemia patients had mutations in ribosomal protein
genes. No mutations were detected in RPS14, RPS24 or RPL35A. All patients with
RPS19 and RPL5 mutations had physical abnormalities. Remarkably, cleft palate
was seen in two patients with RPL5 mutations, and thumb anomalies were seen in
six patients with an RPS19 or RPL5 mutation. In contrast, a small-for-date
phenotype was seen in five patients without an RPL5 mutation.
CONCLUSIONS: We observed a slightly lower frequency of mutations in the
ribosomal protein genes in patients with Diamond-Blackfan anemia compared to the
frequency reported in western countries. Genotype-phenotype data suggest an
association between anomalies and RPS19 mutations, and a negative association
between small-for-date phenotype and RPL5 mutations. Diamond Blackfan anemia (DBA) is an inherited erythroblastopenia associated with
mutations in at least 8 different ribosomal protein genes. Mutations in the gene
encoding ribosomal protein S19 (RPS19) have been identified in approximately 25%
of DBA families. Most of these mutations disrupt either the translation or
stability of the RPS19 protein and are predicted to cause DBA by
haploinsufficiency. However, approximately 30% of RPS19 mutations are missense
mutations that do not alter the stability of the RPS19 protein and are
hypothesized to act by a domit negative mechanism. To formally test this
hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation
in which an arginine residue is replaced with a tryptophan residue at codon 62
(RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal.
Conditional expression of RPS19R62W resulted in growth retardation, a mild
anemia with reduced numbers of erythroid progenitors, and significant inhibition
of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated
more than 700 dysregulated genes belonging to the same pathways that are
disrupted in RNA profiles of DBA patient cells. We conclude that RPS19R62W is a
domit negative DBA mutation. Within the decade following the demonstration that mutations in the RPS19 gene
can lead to Diamond-Blackfan anemia (DBA), this disease has become a paradigm
for an emerging group of pathologies linked to defects in ribosome biogenesis.
DBA patients exhibit abnormal pre-rRNA maturation patterns and the majority bear
mutations in one of several ribosomal protein genes that encode structural
components of the ribosome essential for the correct assembly of the ribosomal
subunits. Extensive study of the most frequently mutated gene, RPS19, has shown
that mutations prevent the assembly of the ribosomal protein into forming
pre-ribosomal particles. This defect in ribosome production triggers nucleolar
stress pathways, the activation of which appears to be central to
pathophysiological mechanisms. Why mutations in ribosomal protein genes so
strongly and specifically affect erythropoiesis in DBA remains a challenging
question, especially given the fact that defects in genes encoding nonstructural
ribosome biogenesis factors have been shown to cause diseases other than DBA. A
major problem in understanding the pathophysiological mechanisms in DBA remains
the lack of a suitable animal model. Despite this, considerable strides have
been made over that past few years demonstrating that several factors involved
in the synthesis of ribosomes are targets of disease-causing mutations. Diamond-Blackfan anemia is an autosomal domit disease due to mutations in
nine ribosomal protein encoding genes. Because most mutations are loss of
function and detected by direct sequencing of coding exons, we reasoned that
part of the approximately 50% mutation negative patients may have carried a copy
number variant of ribosomal protein genes. As a proof of concept, we designed a
multiplex ligation-dependent probe amplification assay targeted to screen the
six genes that are most frequently mutated in Diamond-Blackfan anemia patients:
RPS17, RPS19, RPS26, RPL5, RPL11, and RPL35A. Using this assay we showed that
deletions represent approximately 20% of all mutations. The combination of
sequencing and multiplex ligation-dependent probe amplification analysis of
these six genes allows the genetic characterization of approximately 65% of
patients, showing that Diamond-Blackfan anemia is indisputably a ribosomopathy. More than a decade has passed since the initial identification of ribosomal
protein gene mutations in patients with Diamond-Blackfan anemia (DBA), a
hematologic disorder that became the founding member of a class of diseases
known as ribosomopathies. In these diseases, genetic abnormalities that result
in defective ribosome biogenesis cause strikingly tissue-specific phenotypes in
patients, specifically bone marrow failure, craniofacial abnormalities and
skeletal defects. Several animal models and numerous in vitro studies have
demonstrated that the p53 pathway is central to the ribosomopathy phenotype.
Additionally, there is mounting evidence of a link between the dysregulation of
components of the translational machinery and the pathology of various
maligcies. The importance of the role of ribosomal dysfunction in the
pathogenesis of hematologic disorders is becoming clearer, and elucidation of
the underlying mechanisms could have broad implications for both basic cellular
biology and clinical intervention strategies. Mutations in the hematopoietic transcription factor GATA-1 alter the
proliferation/differentiation of hemopoietic progenitors. Mutations in exon 2
interfere with the synthesis of the full-length isoform of GATA-1 and lead to
the production of a shortened isoform, GATA-1s. These mutations have been found
in patients with Diamond-Blackfan anemia (DBA), a congenital erythroid aplasia
typically caused by mutations in genes encoding ribosomal proteins. We sequenced
GATA-1 in 23 patients that were negative for mutations in the most frequently
mutated DBA genes. One patient showed a c.2T > C mutation in the initiation
codon leading to the loss of the full-length GATA-1 isoform. |
List the human acrocentric chromosomes that are involved in Robertsonian translocation. | Robertsonian translocations (ROBs) are the most common chromosomal rearrangements in humans. ROBs are whole-arm rearrangements between the acrocentric chromosomes 13, 14, 15, 21, and 22. | The pattern of association of acrocentric chromosomes was examined in ten and
five carriers of a 15/21 and a 13/14 Robertsonian translocation, respectively,
and was compared with that of the same numbers of relatives with normal
karyotypes. In the carriers of 15/21 translocation, the number of large
associations (involving more than two acrocentrics) and the association
frequencies for individual acrocentric chromosomes, were significantly higher
than in the control group. The mean number of associations of the single
homologs of the translocation chromosomes was much higher than that of the other
acrocentrics. In the carriers of 13/14 translocations, only the association
frequency for chromosome 13 was higher than in the normal relatives. The
uninvolved chromosomes homologous to those involved in translocation showed an
insignificant increase in associations in comparison with the other
acrocentrics. These results suggest that some mechanism within the cells
compensates for the effect of missing acrocentrics or of acrocentrics lacking
NORs on the number of associations. The possible relations of this phenomenon to
the activity of the nucleolus organizing regions are discussed. We characterized 21 t(13;14) and 3 t(14;21) Robertsonian translocations for the
presence of DNA derived from the short arms of the translocated acrocentric
chromosomes and identified their centromeres. Nineteen of these 24 translocation
carriers were unrelated. Using centromeric alpha-repeat DNA as
chromosome-specific probe, we found by in situ hybridization that all 24
translocation chromosomes were dicentric. The chromatin between the two
centomeres did not stain with silver, and no hybridization signal was detected
with probes for rDNA or beta-satellite DNA that flank the distal and proximal
ends of the rDNA region on the short arm of the acrocentrics. By contrast, all
24 translocation chromosomes gave a distinct hybridization signal when satellite
III DNA was used as probe. This result strongly suggests that the chromosomal
rearrangements leading to Robertsonian translocations occur preferentially in
satellite III DNA. We hypothesize that guanine-rich satellite III repeats may
promote chromosomal recombination by formation of tetraplex structures. The
findings localize satellite III DNA to the short arm of the acrocentric
chromosomes distal to centromeric alpha-repeat DNA and proximal to
beta-satellite DNA. The present study explores the origin of human Robertsonian translocations (RT)
and the causes of the nonrandom participation of the different acrocentrics in
them. Satellite associations have been analysed in 966 cells from 8 persons, and
1266 RT with ascertainment have been collected from the literature. The
observation that the chromosomes preferentially taking part in satellite
associations vary between individuals is confirmed. However, since a preferred
chromosome appears to associate at random with the others, this phenomenon
should not add to the nonrandomness of the RT. Most RT presumably arise through
adjacent chromatid exchanges corresponding to mitotic chiasmata, in the
pericentric regions of the acrocentrics. Our working hypothesis is that there is
a basic exchange rate between any two acrocentrics. The surplus of t(14q21q) is
presumed to depend on these two chromosomes having a homologous pericentric
region. The 10-20 times higher incidence of t(13q14q) as compared with other RT
is best explained by crossing-over between homologous, but relatively inverted,
segments in these chromosomes. Of the 246 RT ascertained through repeated
abortions or infertility, 56 were found through the latter. Of these, chromosome
14 was involved in 51. The infertility may be caused by a small deletion of 14q,
as is often the case in 15q in Prader-Willi syndrome. In all RT ascertained
through 21 or 13 trisomy, respectively, the relevant chromosome is one of the
participants. Our data thus do not give any support to the idea of
interchromosomal effects exerted by RT. In situ hybridization of five new and one previously described alpha-satellite
sequences isolated from chromosome 21 libraries gave the following chromosomal
distribution patterns: (a) two sequences (pTRA-1 and -4) hybridizing to
chromosomes 13, 14, 15, 21, and 22 (also 19 and 20); (b) one sequence (pTRA-7)
hybridizing to chromosome 14; and (c) three sequences (pTRA-2, -11 and -15)
hybridizing to chromosomes 13, 14, and 21, with significant but weaker signals
on 15 and 22. These results suggested the sharing of alphoid domains between
different acrocentric chromosomes and the coexistence of multiple domains on
each chromosome. Analysis of somatic cell hybrids carrying a single human
acrocentric chromosome using pTRA-2 demonstrated a higher-order repeating
structure common to chromosomes 13, 14, and 21, but not to 15 and 22, providing
direct evidence for sequence homogenization in this domain among the former
three chromosomes. We present a model of evolution and genetic exchange of alpha
sequences on the acrocentric chromosomes which can satisfactorily explain these
and previous observations of (a) two different alphoid subfamilies, one common
to chromosomes 13 and 21 and the other common to chromosomes 14 and 22, (b) a
different alphoid subfamily on chromosome 22, and (c) nonrandom participation of
chromosomes 13 and 14, and 14 and 21 in Robertsonian translocations. We report a new subfamily of alpha satellite DNA (pTRA-2) which is found on all
the human acrocentric chromosomes. The alphoid nature of the cloned DNA was
established by partial sequencing. Southern analysis of restriction
enzyme-digested DNA fragments from mouse/human hybrid cells containing only
human chromosome 21 showed that the predomit higher-order repeating unit for
pTRA-2 is a 3.9 kb structure. Analysis of a "consensus" in situ hybridisation
profile derived from 13 normal individuals revealed the localisation of 73% of
all centromeric autoradiographic grains over the five acrocentric chromosomes,
with the following distribution: 20.4%, 21.5%, 17.1%, 7.3% and 6.5% on
chromosomes 13, 14, 21, 15 and 22 respectively. An average of 1.4% of grains was
found on the centromere of each of the remaining 19 nonacrocentric chromosomes.
These results indicate the presence of a common subfamily of alpha satellite DNA
on the five acrocentric chromosomes and suggest an evolutionary process
consistent with recombination exchange of sequences between the nonhomologues.
The results further suggests that such exchanges are more selective for
chromosomes 13, 14 and 21 than for chromosomes 15 and 22. The possible role of
centromeric alpha satellite DNA in the aetiology of 13q14q and 14q21q
Robertsonian translocations involving the common and nonrandom association of
chromosomes 13 and 14, and 14 and 21 is discussed. Acrocentric bivalent associations were studied in 232 human male germ cells at
pachytene in order to understand better the preferential involvement of
chromosomes 13, 14, and 21 in Robertsonian translocations. The tendency of each
acrocentric bivalent to associate with another was not correlated with NOR
activity, as measured by silver staining. Good agreement was noticed between
their ability to associate and the amount of satellite DNA in human acrocentric
chromosomes. The distribution of two-by-two acrocentric bivalent associations
was random. In order to reconcile this result with the nonrandom distribution of
Robertsonian translocations, a molecular hypothesis is proposed. The model is
based on homology of recombinational sites, interspersed at regular interval in
satellite DNA, which could increase the probability of accidental unequal
crossing-over between two specific acrocentric chromosomes. Satellite III DNA has been located by in situ hybridization in chromosomes 1,
3--5, 7, 9, 10, 13--18, 20--22, and Y and ribosomal DNA (rDNA) in the
acrocentric chromosomes 13--15, 21, and 22. In the acrocentric chromosomes, the
satellite DNA is located in the short arm. Here we report comparisons by in situ
hybridization of the amount of satellite DNA in Robertsonian translocation and
"normal variant" chromosomes with that in their homologs. In almost all
dicentric Robertsonian translocations, the amount of satellite DNA is less than
that in the normal homologs, but it is rarely completely absent, indicating that
satellite DNA is located between the centromere and the nucleolus organizer
region (NOR) and that the breakpoints are within the satellite DNA. The amount
of satellite DNA shows a range of variation in "normal" chromosomes, and this is
still more extreme in "normal variant" chromosomes, those with large short arm
(p+ or ph+) generally having more satellite DNA than those with small short arms
(p- or ph-). The cytological satellites are heterogeneous in DNA content; some
contain satellite DNA, others apparently do not, and the satellite DNA content
is not related to the size or intensity of fluorescence of the satellites. The
significance of these variations for the putative functions of satellite DNA is
discussed. Translocations involving acrocentric chromosomes are frequent in chromosomal
male infertility. Robertsonian translocations are usually concerned whereas
reciprocal translocations between acrocentric chromosomes are rarely
encountered. The first reciprocal translocation involving the long arms of the
two acrocentric chromosomes 13 and 14 [46,XY,t(13,14)(q33,q22)] is presented in
this paper. The patient presents a severe oligoasthenospermia; testicular
histology shows an important impairment of spermatogenesis. The quadrivalent is
present in all the pachytene nuclei analyzed. A straight contact between the sex
vesicle and the quadrivalent was found in 40.9% of the nuclei. A frequent
asynapsis is localized at the breakpoint region (33.8%). The XY-autosome
association was obtained by the central asynapsis and/or by the terminal
chromomeres of the acrocentric chromosomes involved in the translocation. Most Robertsonian translocations are dicentric, suggesting that the location of
chromosomal breaks leading to their formation occur in the acrocentric short
arm. Previous cytogenetic and molecular cytogenetic studies have shown that few
Robertsonian translocations retain ribosomal genes or beta-satellite DNA.
Breakpoints in satellite III DNA, specifically between two chromosome
14-specific subfamilies, pTRS-47 and pTRS-63, have been indicated for most of
the dicentric 14q21q and 13q14q translocations that have been studied. We have
analyzed the structure of 36 dicentric translocations, using several repetitive
DNA probes that localize to the acrocentric short arm. The majority of the
translocations retained satellite III DNA, while others proved variable in
structure. Of 10 14q21q translocations analyzed, satellite III DNA was
undetected in 1; 6 retained one satellite III DNA subfamily, pTRS-47; and 3
appeared to contain two 14-specific satellite III DNA sub-families, pTRS-47 and
pTRS-63. In 10/11 translocations involving chromosome 15, the presence of
satellite III DNA was observed. Our results show that various regions of the
acrocentric short arm, and, particularly, satellite III DNA sequences, are
involved in the formation of Robertsonian translocations. Members of the long-range, low-copy-number repetitive DNA sequence family chAB4
are located on nine different human chromosome pairs and the Y chromosome, i.e.
on the short arms of all the acrocentrics. To localize the chAB4 sequences more
precisely on the acrocentrics, chAB4-specific probes together with rDNA and a
number of satellite sequences were hybridized to metaphase chromosomes of normal
probands and of carriers of Robertsonian translocations of the frequent types
rob(13q14q) and rob(14q21q). The results demonstrate that chAB4 is located on
both sides of the rDNA on all the acrocentrics; the exact location, however, may
be chromosome specific. Chromosome 22, most probably, is the only chromosome
where chAB4 is found in the direct neighbourhood of the centromere. Fluorescence
in situ hybridization analyses of metaphase chromosomes of carriers of
rob(21q22q) revealed breakpoint diversity for this rare type of Robertsonian
translocation chromosome. A direct involvement of chAB4 sequences in
recombination processes leading to the Robertsonian translocations analysed in
this study can be excluded. Fluorescent in situ hybridization (FISH) was employed in mapping the
alpha-satellite DNA that was revealed in the cosmid libraries specific for human
chromosomes 13, 21, and 22. In total, 131 clones were revealed. They contained
various elements of centromeric alphoid DNA sequences of acrocentric
chromosomes, including those located close to SINEs, LINEs, and classical
satellite sequences. The heterochromatin of acrocentric chromosomes was shown to
contain two different groups of alphoid sequences: (1) those immediately
adjacent to the centromeric regions (alpha 13-1, alpha 21-1, and alpha 22-1
loci) and (2) those located in the short arm of acrocentric chromosomes (alpha
13-2, alpha 21-2, and alpha 22-2 loci). Alphoid DNA sequences from the alpha
13-2, alpha 21-2, and alpha 22-2 loci are apparently not involved in the
formation of centromeres and are absent from mitotically stable marker
chromosomes with a deleted short arm. Robertsonian translocations t(13q; 21q)
and t(14q; 22q), and chromosome 21p-. The heterochromatic regions of chromosomes
13, 21, and 22 were also shown to contain relatively chromosome-specific
repetitive sequences of various alphoid DNA families, whose numerous copies
occur in other chromosomes. Pools of centromeric alphoid cosmids can be of use
in further studies of the structural and functional properties of
heterochromatic DNA and the identification of centromeric sequences. Moreover,
these clones can be employed in high-resolution mapping and in sequencing the
heterochromatic regions of the human genome. The detailed FISH analysis of
numerous alphoid cosmid clones allowed the identification of several new, highly
specific DNA probes of molecular cytogenetic studies--in particular, the
interphase and metaphase analyses of chromosomes 2, 9, 11, 14, 15, 16, 18, 20,
21-13, 22-14, and X. Robertsonian translocations (ROBs) are the most common rearrangements in humans,
contributing significantly to genetic imbalance, fetal wastage, mental
retardation and birth defects. Rob(14q21q) and rob(13q14q), which are formed
predomitly during female meiosis, comprise the majority (approximately 85%)
of all ROBs. Previous studies have shown that the breakpoints are consistently
located within specific regions of the proximal short arms of chromosomes 13,
14, and 21. The high prevalence of these translocations, the consistent
breakpoints found, and the fact that roughly 50% of cases occur sporadically
suggest that the sequences at or near the breakpoints confer susceptibility to
chromosome rearrangement and that the rearrangements occur through a specific
mechanism. To investigate this hypothesis, we developed hamster-human somatic
cell hybrids derived from de novo rob(14q21q) patients that contained the
translocated chromosome segregated from the other acrocentric chromosomes. We
determined the physical order of five satellite III subfamilies on 14p, and
investigated their involvement in formation of these de novo translocations. We report the prenatal diagnosis of a fetus with a de novo Robertsonian
translocation: 45,XY,der(15;15)(q10;q10). Although Robertsonian translocations
are common chromosomal rearrangements, those involving homologous chromosomes
are infrequent. Since chromosome 15 is imprinted, uniparental disomy (UPD) is a
concern when chromosomal rearrangements involving chromosome 15 are identified.
In the present case, UPD studies showed normal biparental inheritance. In
contrast to the fact that most homologous acrocentric rearrangements are
isochromosomes, these results indicate postzygotic formation of a Robertsonian
translocation between biparentally inherited chromosomes 15. Carriers of either homologous or non-homologous acrocentric rearrangements are
at an increased risk for aneuploidy, and, thus, for uniparental disomy (UPD).
Abnormal phenotypes due to genomic imprinting are associated with UPD for the
acrocentric chromosomes 14 and 15. The purpose of this study was to determine
the prevalence of UPD in a population with acrocentric rearrangements (either an
isochromosome or a Robertsonian translocation) and abnormal phenotypes. Fifty
individuals were studied. Of the 50 rearrangements, two were homologous
rearrangements and both showed UPD. Forty-eight were non-homologous Robertsonian
translocations, of which two showed UPD. This study demonstrates that UPD
explains the abnormal phenotypes in some balanced carriers of acrocentric
rearrangements. Our results and the large number of case reports in the
literature suggest that patients with abnormal phenotypes and acrocentric
rearrangements of chromosomes 14 or 15 should be tested for UPD. OBJECTIVE: The purpose of this study was to search for cytologic evidence of
robertsonian translocation formation that involves chromosomes 14q and 21q in
human oogenesis with the use of dual color fluorescent in situ hybridization
with whole chromosome paints.
STUDY DESIGN: The oocytes from a chromosomally normal fetus at 23.5 weeks of
gestation underwent cohybridization with chromosome specific DNA libraries from
chromosomes 14 and 21. The nuclei were scored for the proportion of meiosis I
prophase substages and for hybridization efficiency and were evaluated for the
presence of hybridization signals that were suggestive of heterologous
associations between chromosomes 14q and 21q in zygotene, pachytene, and
diplotene.
RESULTS: A total of 1769 meiotic nuclei were analyzed. Of 272 informative nuclei
at zygotene, pachytene, and diplotene, 1 nucleus at pachytene demonstrated
hybridization signals for chromosomes 14 and 21 that could be consistent with a
robertsonian translocation.
CONCLUSION: A heterologous association between chromosomes 14q and 21q that
possibly represent robertsonian translocation formation was observed
cytologically with the use of fluorescent in situ hybridization. Robertsonian translocations have been well documented in domestic cattle, with
the most commonly occurring fusion involving chromosomes 1 and 29. The
widespread nature of this translocation is indicative of its ancient origin. The
gaur (Bos gaurus) is one of many wild cattle species currently listed as
vulnerable or endangered. Due to the small founder stock and 50 years of
restricted breeding, the captive herd is showing signs of inbreeding and reduced
fertility. Recent cytogenetic analysis of a female gaur at Toronto Zoo found
that the individual contained 2n=57 chromosomes instead of the normal 2n=58,
with an extra submetacentric and the loss of two acrocentric chromosomes being
observed. This study was undertaken to identify the translocation in this
individual and to examine the karyotype of immediate family members. Chromosome
analysis of fibroblast cell cultures was carried out using GTG-banding,
C-banding and FISH (bovine 1 and 29 paints) techniques to characterize the
translocation. Results from the GTG-banding and FISH analyses confirm that the
two autosomes involved in the translocation are the bovine homologues 1 and 29.
A monocentric centromere was observed by C-banding. Chromosome abnormalities
have not been detected in other gaur tested to date. This study demonstrates the
importance of cytogenetic analysis for the establishment of screening protocols
for the assessment of reproductive potential in this and other exotic bovinae. Robertsonian translocation have been well documented in domestic cattle, with
the most commonly occurring fusion involving chromosomes 1 and 29. The
widespread nature of this translocation is indicative of its ancient origin.
Fifty Giemsa's stained metaphase spreads derived from lymphocyte cultures of the
Thai gaur were analyzed for each animal. The Thai gaur had diploid chromosome
number of 2n = 57 in male and 2n = 56 in female instead of the normal 2n = 58.
The 2n = 57 in male chromosomes presence of an extra submetacentric chromosome
and loss of two acrocentric chromosomes was observed [XY, 57, rob (1;29)]. The
2n = 56 in female chromosomes presence of two extra submetacentric chromosomes
and loss of four acrocentric chromosomes was observed [XX, 56, rob (1;29)].
Results from the Giemsa's stained analyses confirm that the two autosomes (2n =
57) and four autosomes (2n = 56) involved in the translocation are the bovine
homologues 1 and 29. The prenatal diagnosis is currently widely spread and facilitates the acquiring
of important genetic information about the fetus by a rate extremely accelerate
and considered without precedent. In this paper, we like to present our
experience concerning the genetic diagnosis and counseling offered for
pregcies in which a structural chromosomal aberration was found. The study
group is formed by 528 prenatal samples of amniotic fluid and chorionic villi,
received by our laboratory from 2006 through October 2012 for cytogenetic
diagnosis. The appropriate genetic investigation was selected based on the
indications for prenatal diagnosis. The cases with structural chromosomal
anomalies and polymorphic variants were analyzed as regard to the maternal age,
gestational age, referral indications and type of chromosomal anomaly found. A
total number of 21 structural chromosomal anomalies and polymorphic variants
were identified in the study group. Out of 21 structural chromosomal anomalies
and polymorphic variants, six deletions and microdeletions, four situations with
abnormal long "p" arm of acrocentric chromosomes, two duplications, two
reciprocal translocations, two inversions, two additions, one Robertsonian
translocation associating trisomy 13, one 9q heteromorphism and one complex
chromosome rearrangement were noticed. To the best of our knowledge, this is the
first Romanian study in which the diagnostic strategies and the management of
the prenatal cases with structural rearrangements are presented. The data
provided about the diagnosis strategy and the management of the prenatal cases
with structural chromosomal anomalies represents a useful tool in genetic
counseling of pregcies diagnosed with rare structural chromosomal anomalies. Despite that Robertsonian translocations (ROBs) are the most common chromosomal
rearrangements in humans (1/1000 individuals), an exact breakpoint and the
molecular mechanisms leading to their formation are still not well known. This
is partly due to the fact that Human Genome Project did not provide any map or
sequence for the acrocentric short arms. The main aim of our studies was to
narrow the breakpoints in de novo arising and in familial cases of the most
frequently occurring ROBs, using eight, previously not tested clones derived
from 21p. Our results from PCR and FISH analysis showed that only the clones
CR382285, CR382287, and a small fragment of CR382332 are retained in the
examined ROBs. Moreover, interphase FISH on monochromosomal hybrids verified the
orientation of studied clones in relation to centromeres of chromosomes 14 and
21. Given our results, we propose localization of the breakpoints in or nearby
to clone CR382332. Summarizing, our results allowed to narrow the region where
the breakpoints are localized and demonstrated that their position could be the
same in all common ROBs. |
Is tirilazad effective for treatment of aneurysmal subarachnoid haemorrhage? | No. Based on meta-analysis, there is no evidence that tirilazad, in addition to nimodipine, reduces mortality or improves poor outcome in patients with aneurysmal subarachnoid haemorrhage. | Tirilazad mesylate, a nonglucocorticoid 21-aminosteroid, has been shown in
experimental models to reduce vasospasm following subarachnoid hemorrhage (SAH)
and to reduce infarct size from focal cerebral ischemia. To test whether
treatment with tirilazad would reduce ischemic symptoms from vasospasm and
improve overall outcome in patients with ruptured aneurysms, a prospective
randomized, double-blind, vehicle-controlled trial was conducted at 41
neurosurgical centers in Europe, Australia, and New Zealand. One thousand
twenty-three patients were randomly assigned to receive 0.6, 2, or 6 mg/kg per
day of intravenously administered tirilazad or a placebo containing the citrate
vehicle. All patients were also treated with intravenously administered
nimodipine. Patients receiving 6 mg/kg per day of tirilazad had reduced
mortality (p = 0.01) and a greater frequency of good recovery on the Glasgow
Outcome Scale 3 months after SAH (p = 0.01) than similar patients treated with
vehicle. There was a reduction in symptomatic vasospasm in the group that
received 6 mg/kg per day tirilazad; however, the difference was not
statistically significant (p = 0.048). The benefits of treatment with tirilazad
were predomitly shown in men rather than in women. There were no material
differences between the outcomes in the groups treated with 0.6 and 2 mg/kg
tirilazad per day and the group treated with vehicle. Tirilazad was well
tolerated at all three dose levels. These observations suggest that tirilazad
mesylate, at a dosage of 6 mg/kg per day, is safe and improves overall outcome
in patients (especially in men) who have experienced an aneurysmal SAH. The 21-aminosteroid lipid-peroxidation inhibitor, tirilazad mesylate (U-74006F),
recently was shown in a large multinational Phase III clinical trial to decrease
mortality and improve neurological recovery in patients 3 months after onset of
aneurysmal subarachnoid hemorrhage (SAH). A major tirilazad metabolite in
animals and man, U-89678 is formed when the 4-5 double bond in the A-ring is
reduced and has been postulated to contribute significantly to tirilazad's
neuroprotective effects. In the first experiment of the present study, the
authors compared the effects of tirilazad and U-89678 on acute blood-brain
barrier (BBB) damage in rats subjected to SAH via injection of 300 microliters
of autologous nonheparinized blood under the dura of the left cortex. The rats
were treated by intravenous administration of either 0.3 or 1.0 mg/kg of
tirilazad or U-89678 10 minutes before and 2 hours after SAH, and BBB damage was
quantified according to the extravasation of the protein-bound Evans' blue dye
into the injured cortex 3 hours post-SAH. The results revealed that 0.3 and 1.0
mg/kg tirilazad significantly reduced SAH-induced BBB damage 35.2% (p < 0.05)
and 60.6% (p < 0.0001), respectively, in comparison to treatment with vehicle.
The 0.3- and 1.0-mg/kg doses of U-89678 also decreased injury by 39.1% (p <
0.05) and 21.3% (not significant), respectively. In the second experiment, the
investigators assessed the relative abilities of tirilazad and U-89678 to
protect cultured neurons from iron-induced lipid peroxidative injury. Fetal
mouse spinal cord cells were pretreated with 3, 10, or 30 microM tirilazad or
U-89678 for 1 hour and then exposed to 200 microM ferrous ammonium sulfate (FAS)
for 40 minutes. Cell viability was measured in terms of the uptake of
[3H]alpha-(methyl)-aminoisobutyric acid 45 minutes after the FAS treatment. Both
compounds enhanced neuronal survival in a concentration-dependent fashion.
Although the two were equally efficacious, U-89678 was slightly more potent than
its parent. On the basis of these findings, the authors conclude that the
tirilazad metabolite, U-89678, possesses vaso- and neuroprotective properties
that are essentially equivalent to the parent 21-aminosteroid. Hence, U-89678
probably contributes to the protective effects of tirilazad in SAH and other
insults to the central nervous system. Subarachnoid haemorrhage (SAH) following cerebral aneurysm rupture or trauma can
result in the induction of secondary ischaemic brain damage via a decrease in
microvascular perfusion, a disruption of the blood-brain barrier and consequent
vasogenic oedema, and the delayed spasm of the major cerebral arteries (i.e.
vasospasm). It is increasingly apparent that oxygen radical-induced,
iron-catalyzed lipid peroxidation (LP) within the subarachnoid blood and
vascular wall plays a key role in the occurrence of these secondary events.
Tirilazad mesylate is a potent cytoprotective inhibitor of LP that works by a
combination of radical scavenging and membrane stabilizing properties. It has
been demonstrated to attenuate the acute and delayed vascular consequences of
SAH and to protect the brain against ischaemic insults. Much of its action is
mediated by an effect on the vascular endothelium, although it also appears to
exert some direct neuroprotection and to inhibit LP in the subarachnoid blood.
These actions of tirilazad in experimental SAH are reviewed. To test the safety and efficacy of tirilazad mesylate, a nonglucocorticoid
21-aminosteroid, in improving the outcome of patients with aneurysmal
subarachnoid hemorrhage (SAH), 902 patients were enrolled in a prospective
randomized, double-blind, vehicle-controlled trial at 54 North American
neurosurgical centers. Five patients were excluded prior to receiving any study
drug. Of 897 patients who received at least one dose of study medication, 300
received a placebo containing a citrate vehicle, 298 received 2 mg/kg per day
tirilazad, and 299 received 6 mg/kg per day tirilazad, all administered
intravenously beginning within 48 hours of the SAH and continuing through 10
days posthemorrhage. All patients were also treated with orally administered
nimodipine. At 3 months post-SAH, there were no significant differences (p <
0.025) among the groups with regard to mortality rate, favorable outcome on the
Glasgow Outcome Scale, or employment status. During the first 14 days after the
SAH, there were no significant differences among the groups in the incidence or
severity of clinically symptomatic or angiographically identifiable cerebral
vasospasm. Mortality data stratified by gender and neurological grade on
admission (assessed according to a modified World Federation of Neurological
Surgeons scale) demonstrated that the men with Grades IV to V had a 33%
mortality rate in the vehicle group, 52% in the 2 mg/kg per day tirilazad group
(p = 0.29), and 5% in the 6 mg/kg per day tirilazad group (p = 0.03). Tirilazad
was well tolerated at both dose levels. Tirilazad mesylate at dosage levels of
up to 6 mg/kg per day for 8 to 10 days following SAH did not improve the overall
outcome in patients with aneurysmal SAH in this trial. The differences in the
efficacy of tirilazad in this trial and a previously reported trial in Europe,
Australia, and New Zealand, in which dosage levels of tirilazad of 6 mg/kg per
day reduced mortality rates and increased good recovery, may be a result of
differences in admission characteristics of the patients and/or differences in
management protocols, including the use of anticonvulsant medications. This study used data from a multinational phase III randomized, double-blind,
vehicle-controlled trial to evaluate the cost-effectiveness of tirilazad
mesylate (Freedox) in the treatment of aneurysmal subarachnoid hemorrhage. In
men, therapy with 6 mg/kg per day of tirilazad mesylate was associated with
significantly increased survival, increased cost of care, and ratios of cost per
death averted that compare favorably with the ratios of other life and death
interventions. In women, it appeared to have no effects on costs or survival.
Further clinical studies may provide additional information about the
cost-effectiveness of this intervention. Tirilazad mesylate, a nonglucocorticoid 21-aminosteroid, has been used in two
randomized, double-blind, vehicle-controlled trials in Europe, Australia, New
Zealand, and in North America in patients with aneurysmal subarachnoid
hemorrhage. The first trial has been concluded, enrolled 1023 patients, and
demonstrated a dramatic reduction in mortality from 27% to 3% (p = 0.01) in
males receiving 6 mg/kg/day tirilazad for 10 days, when compared to
vehicle-treated patients. There was also a less incidence of symptomatic
vasospasm, and the frequency of hypertensive-hypervolemic-hemodilution therapy
was significantly reduced. The reduction in mortality rate was remarkable,
however the benefits of treatment with tirilazad were predomitly shown in men
rather than in women. This clinical trial suggest that tirilazad mesylate, at a
dosage of 6 mg/kg/day, improves overall outcome in aneurysmal subarachnoid
hemorrhage patients. Further data from the North America trial and the trial in
women receiving higher doses of tirilazad are still pending. BACKGROUND: Tirilazad is a non-glucocorticoid, 21-aminosteriod that inhibits
lipid peroxidation. It had neuroprotective effects in experimental ischemic
stroke and reduced angiographic vasospasm after experimental subarachnoid
hemorrhage (SAH). Five randomized clinical trials of tirilazad were conducted in
patients with SAH. We performed a meta-analysis of these trials to assess the
effect of tirilazad on unfavorable outcome, symptomatic vasospasm, and cerebral
infarction after SAH.
METHODS: Data from 3,797 patients were analyzed and modeled using random effect
and Mantel-Haenszel meta-analyses and multivariable logistic regression to
determine the effect of tirilazad on clinical outcome, symptomatic vasospasm,
and cerebral infarction. Clinical outcome was assessed 3 months after SAH using
the Glasgow outcome scale, and symptomatic vasospasm was defined by clinical
criteria with laboratory and radiological exclusion of other causes of
neurological deterioration.
RESULTS: The five trials were randomized, double-blind, and placebo-controlled.
Tirilazad did not significantly decrease unfavorable clinical outcome on the GOS
(odds ratio [OR] 1.04, 95% confidence interval [CI] 0.89-1.20) or cerebral
infarction (OR 1.04, 95% CI 0.89-1.22). There was a significant reduction in
symptomatic vasospasm in patients treated with tirilazad (OR 0.80, 95% CI
0.69-0.93). There was no heterogeneity across the five trials.
CONCLUSION: Tirilazad had no effect on clinical outcome but did decrease
symptomatic vasospasm in five trials of aneurysmal SAH. The dissociation between
clinical outcome and symptomatic vasospasm deserves further investigation. OBJECTIVE: Cerebral vasospasm is a major source of morbidity and mortality
following aneurysmal subarachnoid hemorrhage (SAH). A variety of therapies have
been utilized to prevent or treat vasospasm. Despite the large number of
clinical trials, few randomized controlled trials (RCTs) of sufficient quality
have been published. We review the RCTs and meta-analyses in the literature
regarding the treatment and prevention of cerebral vasospasm following
aneurysmal SAH.
METHODS: A literature search of MEDLINE, the Cochrane Controlled Trials
Registry, and the National Institutes of Health/National Library of Medicine
clinical trials registry was performed in January 2010 using predefined search
terms. These trials were critically reviewed and categorized based on
therapeutic modality.
RESULTS: Forty-four RCTs and 9 meta-analyses met the search criteria.
Significant findings from these trials were analyzed. The results of this study
were as follows: nimodipine demonstrated benefit following aneurysmal SAH; other
calcium channel blockers, including nicardipine, do not provide unequivocal
benefit; triple-H therapy, fasudil, transluminal balloon angioplasty,
thrombolytics, endothelin receptor antagonists, magnesium, statins, and
miscellaneous therapies such as free radical scavengers and antifibrinolytics
require additional study. Tirilazad is ineffective.
CONCLUSIONS: There are many possible successful treatment options for preventing
vasospasm, delayed ischemic neurologic deficits, and poor neurologic outcome
following aneurysmal subarachnoid hemorrhage; however, further multicenter RCTs
need to be performed to determine if there is a significant benefit from their
use. Nimodipine is the only treatment that provided a significant benefit across
multiple studies. |
Which protein is the main marker of Cajal bodies? | Coilin is widely known as the protein marker of the Cajal body, a subnuclear domain important to the biogenesis of small nuclear ribonucleoproteins and telomerase, complexes that are crucial to pre-messenger RNA splicing and telomere maintenance, respectively The Cajal body has now regained the interest of biologists, due to the isolation of a protein marker, coilin. | Cajal bodies (coiled bodies, CBs) are nuclear organelles of unknown function and
are characterized by a wide variety of components including various basal
transcription and cell cycle proteins, the nucleolar proteins fibrillarin and
Nopp140, numerous small nuclear ribonucleoproteins, the survival motor neuron
protein complex, and the marker protein, p80 coilin. To gain insight into the
role of p80 coilin in CBs, we have cloned the murine gene Coil and have mapped
it to the distal portion of chromosome band 11D. The approximately 2.6-kb
transcript is detectable in all tissues analyzed, with the highest levels in
brain and testis. Sequence analysis shows that, like its human counterpart, the
mouse coilin gene is composed of seven exons and spans nearly 30 kb of genomic
DNA. The predicted amino acid sequence reveals two conserved N- and C-terminal
domains, and comparison with the Xenopus SPH-1 protein reveals that these three
genes are indeed orthologous. These results should facilitate gene disruption
experiments aimed at creating a genetic model system to study CBs. The Cajal (coiled) body is a discrete nuclear organelle that was first described
in mammalian neurons in 1903. Because the molecular composition, structure, and
function of Cajal bodies were unknown, these enigmatic structures were largely
ignored for most of the last century. The Cajal body has now regained the
interest of biologists, due to the isolation of a protein marker, coilin.
Despite current widespread use of coilin to identify Cajal bodies in various
cell types, its structure and function are still little understood. Here, I
would like to discuss what we have learned about coilin and suggest a possible
role for coilin in RNA processing and cellular trafficking, especially in
relation to Cajal bodies and nucleoli. Although coilin has been investigated
primarily in somatic cells, I will emphasize the advantages of using the
amphibian oocyte to study nuclear proteins and organelles. Cajal bodies are small nuclear organelles first described nearly 100 years ago
by Ramón y Cajal in vertebrate neural tissues. They have since been found in a
variety of animal and plant nuclei, suggesting that they are involved in basic
cellular processes. Cajal bodies contain a marker protein of unknown function,
p80-coilin, and many components involved in transcription and processing of
nuclear RNAs. Among these are the three eukaryotic RNA polymerases and factors
required for transcribing and processing their respective nuclear transcripts:
mRNA, rRNA, and pol III transcripts. A model is discussed in which Cajal bodies
are the sites for preassembly of transcriptosomes, unitary particles involved in
transcription and processing of RNA. A parallel is drawn to the nucleolus and
the preassembly of ribosomes, which are unitary particles involved in
translation of proteins. SMN, the affected protein in spinal muscular atrophy (SMA), is a cytoplasmic
protein that also occurs in nuclear structures called "gems" and is involved in
snRNP maturation. Coilin-p80 is a marker protein for nuclear Cajal bodies
(coiled bodies; CBs) which are also involved in snRNP maturation, storage or
transport. We now show that gems and CBs are present in all fetal tissues, even
those that lack gems/CBs in the adult. Most gems and CBs occur as separate
nuclear structures in fetal tissues, but their colocalization increases with
fetal age and is almost complete in the adult. In adult tissues, up to half of
all gems/CBs are inside the nucleolus, whereas in cultured cells they are almost
exclusively nucleoplasmic. The nucleolar SMN is often more diffusely
distributed, compared with nucleoplasmic gems. Up to 30% of cells in fetal
tissues have SMN distributed throughout the nucleolus, instead of forming gems
in the nucleoplasm. The results suggest a function for gems distinct from Cajal
bodies in fetal nuclei and a nucleolar function for SMN. Spinal cord, the
affected tissue in SMA, behaves differently in several respects. In both fetal
and adult motor neurons, many gems/CBs occur as larger bodies closely associated
with the nucleolar perimeter. Uniquely in motor neurons, gems/CBs are more
numerous in adult than in fetal stages and colocalization of gems and CBs occurs
earlier in development. These unusual features of motor neurons may relate to
their special sensitivity to reduced SMN levels in SMA patients. In vitellogenic oocytes of Tenebrio molitor (inactive stage), numerous
fibrogranular nuclear bodies (NBs) are present. Using immunofluorescent
microscopy, these NBs were shown to contain pre-mRNA splicing factors (small
nuclear [sn] RNPs and SR-protein, SC35) as well as RNA polymerase II. A limited
set of NBs also contained coilin, a marker protein for Cajal bodies (CBs). We
suggest that in T. molitor oocytes, coilin-containing NBs, which also contain
splicing factors and RNA polymerase II, seem to represent CBs. In the species
studied, no morphological features of CBs were established as compared with
other NBs, which do not contain coilin. Microinjectons in oocytes of myc-tagged
coilin mRNA, followed by revealing newly translated protein with antibody
specific for this tag, have shown targeting of myc-coilin with CBs. The own and
literary data on the morphology and molecular composition of CBs are discussed
in terms of searching for criteria for CB identification in cells of different
origin, and at active and inactive stages. Coilin is a marker protein for the Cajal body, a subnuclear domain acting as a
site for assembly and maturation of nuclear RNA-protein complexes. Using a yeast
two-hybrid screen to identify coilin-interacting proteins, we have identified
hCINAP (human coilin interacting nuclear ATPase protein), a nuclear factor of
172 amino acids with a P-loop nucleotide binding motif and ATPase activity. The
hCINAP protein sequence is highly conserved across its full-length from human to
plants and yeast and is ubiquitously expressed in all human tissues and cell
lines tested. The yeast orthologue of CINAP is a single copy, essential gene.
Tagged hCINAP is present in complexes containing coilin in mammalian cells and
recombit, Escherichia coli expressed hCINAP binds directly to coilin in
vitro. The 214 carboxyl-terminal residues of coilin appear essential for the
interaction with hCINAP. Both immunofluorescence and fluorescent protein tagging
show that hCINAP is specifically nuclear and distributed in a widespread,
diffuse nucleoplasmic pattern, excluding nucleoli, with some concentration also
in Cajal bodies. Overexpression of hCINAP in HeLa cells results in a decrease in
the average number of Cajal bodies per nucleus, consistent with it affecting
either the stability of Cajal bodies and/or their rate of assembly. The hCINAP
mRNA is an alternatively spliced transcript from the TAF9 locus, which encodes
the basal transcription factor subunit TAFIID32. However, hCINAP and TAFIID32
mRNAs are translated from different ATG codons and use distinct reading frames,
resulting in them having no identity in their respective protein sequences. Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by
loss of spinal motor neurons. The gene encoding the survival of motor neurons
(SMN) protein is mutated in >95% of SMA cases. SMN is the central component of a
large oligomeric complex, including Gemins2-7, that is necessary and sufficient
for the in vivo assembly of Sm proteins onto the small nuclear (sn)RNAs that
mediate pre-mRNA splicing. After cytoplasmic assembly of the Sm core, both SMN
and splicing snRNPs are imported into the nucleus, accumulating in Cajal bodies
for additional snRNA maturation steps before targeting to splicing factor
compartments known as "speckles." In this study, we analyzed the function of
individual SMN complex members by RNA interference (RNAi). RNAi-mediated
knockdown of SMN, Gemin2, Gemin3, and Gemin4 each disrupted Sm core assembly,
whereas knockdown of Gemin5 and Snurportin1 had no effect. Assembly activity was
rescued by expression of a GFP-SMN construct that is refractive to RNAi but not
by similar constructs that contain SMA patient-derived mutations. Our results
also demonstrate that Cajal body homeostasis requires SMN and ongoing snRNP
biogenesis. Perturbation of SMN function results in disassembly of Cajal bodies
and relocalization of the marker protein, coilin, to nucleoli. Moreover, in
SMN-deficient cells, newly synthesized SmB proteins fail to associate with U2
snRNA or accumulate in Cajal bodies. Collectively, our results identify a
previously uncharacterized function for Gemin3 and Gemin4 in Sm core assembly
and correlate the activity of this pathway with SMA. The Cajal body, originally identified over 100 years ago as a nucleolar
accessory body in neurons, has come to be identified with nucleoplasmic
structures, often quite tiny, that contain coiled threads of the marker protein,
coilin. The interaction of coilin with other proteins appears to increase the
efficiency of several nuclear processes by concentrating their components in the
Cajal body. The best-known of these processes is the modification and assembly
of U snRNPs, some of which eventually form the RNA splicing machinery, or
spliceosome. Over the last 10 years, research into the function of Cajal bodies
has been greatly stimulated by the discovery that SMN, the protein deficient in
the inherited neuromuscular disease, spinal muscular atrophy, is a Cajal body
component and has an essential role in the assembly of spliceosomal U snRNPs in
the cytoplasm and their delivery to the Cajal body in the nucleus. Protein phosphorylation by kinases plays a central role in the regulation and
coordination of multiple biological processes. In general, knowledge on kinase
specificity is restricted to substrates identified in the context of specific
cellular responses, but kinases are likely to have multiple additional
substrates and be integrated in signaling networks that might be spatially and
temporally different, and in which protein complexes and subcellular
localization can play an important role. In this report the substrate
specificity of atypical human vaccinia-related kinases (VRK1 and VRK2) using a
human peptide-array containing 1080 sequences phosphorylated in known signaling
pathways has been studied. The two kinases identify a subset of potential
peptide targets, all of them result in a consensus sequence composed of at least
four basic residues in peptide targets. Linear peptide arrays are therefore a
useful approach in the characterization of kinases and substrate identification,
which can contribute to delineate the signaling network in which VRK proteins
participate. One of these target proteins is coilin; a basic protein located in
nuclear Cajal bodies. Coilin is phosphorylated in Ser184 by both VRK1 and VRK2.
Coilin colocalizes and interacts with VRK1 in Cajal bodies, but not with the
mutant VRK1 (R358X). VRK1 (R358X) is less active than VRK1. Altered regulation
of coilin might be implicated in several neurological diseases such as ataxias
and spinal muscular atrophies. Human coilin interacting nuclear ATPase protein (hCINAP) directly interacts with
coilin, a marker protein of Cajal Bodies (CBs), nuclear organelles involved in
the maturation of small nuclear ribonucleoproteins UsnRNPs and snoRNPs. hCINAP
has previously been designated as an adenylate kinase (AK6), but is very
atypical as it exhibits unusually broad substrate specificity, structural
features characteristic of ATPase/GTPase proteins (Walker motifs A and B) and
also intrinsic ATPase activity. Despite its intriguing structure, unique
properties and cellular localization, the enzymatic mechanism and biological
function of hCINAP have remained poorly characterized. Here, we offer the first
high-resolution structure of hCINAP in complex with the substrate ADP (and
dADP), the structure of hCINAP with a sulfate ion bound at the AMP binding site,
and the structure of the ternary complex hCINAP-Mg(2+) ADP-Pi. Induced fit
docking calculations are used to predict the structure of the hCINAP-Mg(2+)
ATP-AMP ternary complex. Structural analysis suggested a functional role for
His79 in the Walker B motif. Kinetic analysis of mutant hCINAP-H79G indicates
that His79 affects both AK and ATPase catalytic efficiency and induces homodimer
formation. Finally, we show that in vivo expression of hCINAP-H79G in human
cells is toxic and drastically deregulates the number and appearance of CBs in
the cell nucleus. Our findings suggest that hCINAP may not simply regulate
nucleotide homeostasis, but may have broader functionality, including control of
CB assembly and disassembly in the nucleus of human cells. Coilin is known as the marker protein for Cajal bodies (CBs), subnuclear domains
important for the biogenesis of small nuclear ribonucleoproteins (snRNPs) which
function in pre-mRNA splicing. CBs associate non-randomly with U1 and U2 gene
loci, which produce the small nuclear RNA (snRNA) component of the respective
snRNP. Despite recognition as the CB marker protein, coilin is primarily
nucleoplasmic, and the function of this fraction is not fully characterized.
Here we show that coilin binds double stranded DNA and has RNase activity in
vitro. U1 and U2 snRNAs undergo a processing event of the primary transcript
prior to incorporation in the snRNP. We find that coilin displays RNase activity
within the CU region of the U2 snRNA primary transcript in vitro, and that
coilin knockdown results in accumulation of the 3' pre-processed U1 and U2
snRNA. These findings present new characteristics of coilin in vitro, and
suggest additional functions of the protein in vivo. Coilin is widely known as the protein marker of the Cajal body, a subnuclear
domain important to the biogenesis of small nuclear ribonucleoproteins and
telomerase, complexes that are crucial to pre-messenger RNA splicing and
telomere maintece, respectively. Extensive studies have characterized the
interaction between coilin and the various other protein components of CBs and
related subnuclear domains; however, only a few have examined interactions
between coilin and nucleic acid. We have recently published that coilin is
tightly associated with nucleic acid, displays RNase activity in vitro, and is
redistributed to the ribosomal RNA (rRNA)-rich nucleoli in cells treated with
the DNA-damaging agents cisplatin and etoposide. Here, we report a specific in
vivo association between coilin and rRNA, U small nuclear RNA (snRNA), and human
telomerase RNA, which is altered upon treatment with DNA-damaging agents. Using
chromatin immunoprecipitation, we provide evidence of coilin interaction with
specific regions of U snRNA gene loci. We have also utilized bacterially
expressed coilin fragments in order to map the region(s) important for RNA
binding and RNase activity in vitro. Additionally, we provide evidence of coilin
involvement in the processing of human telomerase RNA both in vitro and in vivo. Cajal bodies are specialized and dynamic compartments in the nucleus that are
involved in the biogenesis of small nuclear ribonucleoproteins (snRNPs). Because
of the dynamic and varied roles of Cajal bodies, it is of great interest to
identify the components of Cajal bodies to better understand their functions. We
performed a genome-wide screen to identify proteins that colocalize with coilin,
the marker protein of Cajal bodies. In this study, we identified and
characterized Fam118B as a newly discovered component of Cajal bodies. Fam118B
is widely expressed in a variety of cell lines derived from various origins.
Overexpression of Fam118B changes the canonical morphology of Cajal bodies,
whereas depletion of Fam118B disrupts the localization of components of Cajal
bodies, including coilin, the survival of motor neuron protein (SMN) and the Sm
protein D1 (SmD1, also known as SNRPD1). Moreover, depletion of Fam118B reduces
splicing capacity and inhibits cell proliferation. In addition, Fam118B
associates with coilin and SMN proteins. Fam118B depletion reduces symmetric
dimethylarginine modification of SmD1, which in turn diminishes the binding of
SMN to this Sm protein. Taken together, these data indicate that Fam118B, by
regulating SmD1 symmetric dimethylarginine modification, plays an important role
in Cajal body formation, snRNP biogenesis and cell viability. Coilin is a marker protein for subnuclear organelles known as Cajal bodies,
which are sites of various RNA metabolic processes including the biogenesis of
spliceosomal small nuclear ribonucleoprotein particles. Through
self-associations and interactions with other proteins and RNA, coilin provides
a structural scaffold for Cajal body formation. However, despite a conspicuous
presence in Cajal bodies, most coilin is dispersed in the nucleoplasm and
expressed in cell types that lack these organelles. The molecular function of
coilin, particularly of the substantial nucleoplasmic fraction, remains
uncertain. We identified coilin loss-of-function mutations in a genetic screen
for mutants showing either reduced or enhanced expression of an alternatively
spliced GFP reporter gene in Arabidopsis thaliana The coilin mutants feature
enhanced GFP fluorescence and diminished Cajal bodies compared with wild-type
plants. The amount of GFP protein is several-fold higher in the coilin mutants
owing to elevated GFP transcript levels and more efficient splicing to produce a
translatable GFP mRNA. Genome-wide RNA-sequencing data from two distinct coilin
mutants revealed a small, shared subset of differentially expressed genes, many
encoding stress-related proteins, and, unexpectedly, a trend toward increased
splicing efficiency. These results suggest that coilin attenuates splicing and
modulates transcription of a select group of genes. The transcriptional and
splicing changes observed in coilin mutants are not accompanied by gross
phenotypic abnormalities or dramatically altered stress responses, supporting a
role for coilin in fine tuning gene expression. Our GFP reporter gene provides a
sensitive monitor of coilin activity that will facilitate further investigations
into the functions of this enigmatic protein. |
Which mutated gene causes the Chédiak–Higashi Syndrome? | Mutation in the lysosomal trafficking regulator (LYST) gene causes the Chédiak-Higashi syndrome (CHS). | Chediak-Higashi syndrome (CHS) is a rare multiorgan disease entity with
autosomal recessive inheritance characterized by oculocutaneous albinism,
bleeding tendency, recurrent bacterial infections and various neurological
symptoms. Intracellular vesicle formation is deficient, resulting in giant
granules in many cells, e.g. giant melanosomes in the melanocytes. Diagnosis has
been based on morphological examination of peripheral blood and bone marrow,
with giant granules seen in cells of the myeloid lineage and in lymphocytes. The
ultimate diagnostic test is to look for a mutated LYST gene. Most patients
develop an accelerated phase of the disease with deposition of lymphohistiocytes
in the liver, spleen, lymph nodes and bone marrow, resulting in
hepatosplenomegaly, bone marrow infiltration and haemophagocytosis. Peripheral
blood neutropenia becomes more profound as anaemia and thrombocytopenia develop.
Most patients succumb before the age of 10 years. Four patients with CHS are
described, one of whom is a long-term survivor after successful allogeneic bone
marrow transplantation, two succumbed during the accelerated phase and one is
living with a chronic form of the disease.
CONCLUSION: Allogeneic bone marrow transplantation from an HLA-matched sibling
is the therapy of choice and should be performed early. If there is no matched
family donor, an unrelated donor or a placental blood graft is a good
alternative. The clinical picture of CHS is heterogeneous and therapeutic
decisions need to be made on an individual basis. LYST is a large cytosolic protein that influences the biogenesis of
lysosome-related organelles, and mutation of the encoding gene, LYST, can cause
Chediak-Higashi syndrome. Recently, Lyst-mutant mice were recognized to also
exhibit an iris disease resembling exfoliation syndrome, a common cause of
glaucoma in humans. Here, Lyst-mutant iris phenotypes were used in a search for
genes that influence Lyst pathways. In a candidate gene-driven approach, albino
Lyst-mutant mice homozygous for a mutation in Tyr, whose product is key to
melanin synthesis within melanosomes, exhibited complete rescue of Lyst-mutant
iris phenotypes. In a genetic background-driven approach using a DBA/2J strain
of congenic mice, an interval containing Tyrp1 enhanced Lyst-dependent iris
phenotypes. Thus, both experimental approaches implicated the melanosome, an
organelle that is a potential source of oxidative stress, as contributing to the
disease phenotype. Confirming an association with oxidative damage, Lyst
mutation resulted in genetic context-sensitive changes in iris lipid
hydroperoxide levels, being lowest in albino and highest in DBA/2J mice.
Surprisingly, the DBA/2J genetic background also exposed a late-onset
neurodegenerative phenotype involving cerebellar Purkinje-cell degeneration.
These results identify an association between oxidative damage to lipid
membranes and the severity of Lyst-mutant phenotypes, revealing a new mechanism
that contributes to pathophysiology involving LYST. INTRODUCTION: Haemophagocytic syndrome (HS) is a common manifestation of several
congenital disorders characterised by a disruption of lysosomal secretion,
interrupting the cytolytic pathway and triggering a dysfunction in the immune
synapse. In this situation, the recognition of certain extra-immunological
manifestations may help in the diagnostic process.
PATIENTS AND METHODS: We describe the clinical and biological features present
in two brothers with familial haemophagocytic lymphohistiocytosis type 3
(FHL-3), two patients with Griscelli syndrome type 2 (GS-2) and one patient with
Chédiak-Higashi syndrome (CHS).
RESULTS: Mutational assays at UNC13D were carried out on two brothers after
diagnosing an early onset HS in the first one, yielding a positive result in
both cases with a consequent diagnosis of FHL-3. The diagnosis of GS-2 was
supported by positive results of mutational Rab27A studies in one patient with
HS and abnormal pigmentation, and in her cousin who was affected by a similar
abnormal pigmentation. The diagnosis of CHS was established in one patient with
HS, abnormal pigmentation and atypical granules on cytological examination of a
bone marrow smear. Diagnosis was confirmed in this patient by the finding of a
homozygous LYST mutation.
CONCLUSIONS: We point out the importance of recognising the presence of typical
extra-immunological manifestations of certain congenital disorders of lysosome
secretion in patients diagnosed with HS. The association of albinism and
immunodeficiency has played a critical role in the recent identification of the
molecular mechanism involved in these disorders. One of the colors of mink is Aleutian (aa)-a specific gun-metal gray
pigmentation of the fur-commonly used in combination with other color loci to
generate popular colors such as Violet (aammpp) and Sapphire (aapp). The
Aleutian color allele is a manifestation of mink Chédiak-Higashi syndrome (CHS),
which has been described in humans and several other species. As with forms of
CHS in other species, we report that the mink CHS is linked to the lysosomal
trafficking regulator ( LYST ) gene. Furthermore, we have identified a base
deletion (c.9468delC) in exon 40 of LYST, which causes a frameshift and
virtually terminates the LYST product prematurely (p.Leu3156Phefs*37). We
investigated the blood parameters of three wild-type mink and three CHS mink. No
difference in the platelet number between the two groups was observed, but an
accumulation of platelets between the groups appears different when collagen is
used as a coagulant. Microscopic analysis of peripheral blood indicates giant
inclusions in the neutrophils of the Aleutian mink types. Molecular findings at
the LYST locus enable the development of genetic tests for analyzing the color
selection in American mink. BACKGROUND: Mutations in LYST, a gene encoding a putative lysosomal trafficking
protein, cause Chédiak-Higashi syndrome (CHS), an autosomal recessive disorder
typically characterized by infantile-onset hemophagocytic syndrome and
immunodeficiency, and oculocutaneous albinism. A small number of reports of
rare, attenuated forms of CHS exist, with affected individuals exhibiting
progressive neurodegenerative disease beginning in early adulthood with
cognitive decline, parkinsonism, features of spinocerebellar degeneration, and
peripheral neuropathy, as well as subtle pigmentary abnormalities and
subclinical or absent immune dysfunction.
METHODS: In a consanguineous Pakistani kindred with clinical phenotypes
consistent with attenuated CHS, we performed SNP array-based homozygosity
mapping and whole gene sequencing of LYST.
RESULTS: We identified three individuals homozygous for a novel six base pair
in-frame deletion in LYST (c.9827_9832ATACAA), predicting the loss of asparagine
and threonine residues from the LYST transcript (p.Asn3276_Thr3277del), and
segregating with the phenotype in this family.
CONCLUSIONS: We further characterize the neurologic features of the attenuated
form of CHS, and discuss pathophysiologic mechanisms underlying the
neurodegenerative components of CHS. Attenuated CHS is phenotypically
heterogenous and should be considered when young adults develop
neurodegenerative disease and have pigmentary abnormalities. We briefly discuss
surveillance and management of patients with CHS-related neurodegeneration. Chediak-Higashi syndrome (CHS) is an autosomal recessive hereditary disorder in
Japanese Black cattle, caused by a mutation of the Lyst gene. So far, the
mutation has been detected by PCR-restriction fragment length polymorphism
(PCR-RFLP) analysis. However, this method is disadvantaged by its low-throughput
performance. Here, we report an alternative method involving real-time PCR with
TaqMan minor groove binder probes, which shortens the total assay time by more
than 120 min, analyzing 10 samples in a duplicated manner. Using this method, we
examined 102 Japanese Black cattle and found that 8.8% of the cattle were
CHS-carriers. These data indicate that our technique is useful for routine
diagnostic testing for CHS in Japanese Black cattle. BACKGROUND: Chédiak-Higashi syndrome (CHS) is a rare autosomal recessive
disorder characterized by immunodeficiency, neurological dysfunction, and
oculocutaneous albinism. Recently, several clinical CHS phenotypes have been
reported. Here, we report results of a nationwide survey performed to clarify
clinical characteristics and outcomes of CHS patients in Japan.
METHODS: Questionnaires were sent to 287 institutions to collect data regarding
CHS patients diagnosed between 2000 and 2010, including results of lysosomal
trafficking regulator (LYST) gene analysis. Cytotoxicity and degranulation
activity of cytotoxic T lymphocytes were analyzed in available patient samples.
RESULTS: A total of 15 patients diagnosed with CHS were eligible for enrollment
in this study. Of these, 10 (67%) had recurrent bacterial infections, five (33%)
developed life-threatening hemophagocytic lymphohistiocytosis (HLH), and one
patient had complicated maligt lymphoma. Hematopoietic stem cell
transplantation (HSCT) was performed for six patients including three with HLH,
and 10 of the enrolled patients have survived at the time of this writing. LYST
analysis was performed for 10 patients; seven different mutations were detected
in seven patients, whereas no mutation was identified in three patients.
Cytotoxicity and degranulation activity were impaired in patients with and
without LYST mutation.
DISCUSSION: Results of this survey indicate that one or two patients with CHS
were newly diagnosed each year in Japan. The incidence of HLH was not as high as
expected. Mutations of genes other than LYST were suspected in some cases. We
conclude that determining indication for HSCT for CHS patients should be based
on genetic and cytotoxic analysis. BACKGROUND: Autosomal-recessive hereditary spastic paraplegias (AR-HSP) consist
of a genetically diverse group of neurodegenerative diseases characterised by
pyramidal tracts dysfunction. The causative genes for many types of AR-HSP
remain elusive. We tried to identify the gene mutation for AR-HSP with
cerebellar ataxia and neuropathy.
METHODS: This study included two patients in a Japanese family with their
parents who are first cousins. Neurological examination and gene analysis were
conducted in the two patients and two normal family members. We undertook
genome-wide linkage analysis employing single nucleotide polymorphism arrays
using the two patients' DNAs and exome sequencing using one patient's sample.
RESULTS: We detected a homozygous missense mutation (c.4189T>G, p.F1397V) in the
lysosomal trafficking regulator (LYST) gene, which is described as the causative
gene for Chédiak-Higashi syndrome (CHS). CHS is a rare autosomal-recessive
syndrome characterised by hypopigmentation, severe immune deficiency, a bleeding
tendency and progressive neurological dysfunction. This mutation was
co-segregated with the disease in the family and was located at well-conserved
amino acid. This LYST mutation was not found in 200 Japanese control DNAs.
Microscopic observation of peripheral blood in the two patients disclosed large
peroxidase-positive granules in both patients' granulocytes, although they had
no symptoms of immune deficiency or bleeding tendency.
CONCLUSIONS: We diagnosed these patients as having adult CHS presenting spastic
paraplegia with cerebellar ataxia and neuropathy. The clinical spectrum of CHS
is broader than previously recognised. Adult CHS must be considered in the
differential diagnosis of AR-HSP. Peripheral neuropathy (PN) has been reported in idiopathic and hereditary forms
of parkinsonism, but the pathogenic mechanisms are unclear and likely
heterogeneous. Levodopa-induced vitamin B12 deficiency has been discussed as a
causal factor of PN in idiopathic Parkinson's disease, but peripheral nervous
system involvement might also be a consequence of the underlying
neurodegenerative process. Occurrence of PN with parkinsonism has been
associated with a panel of mitochondrial cytopathies, more frequently related to
a nuclear gene defect and mainly polymerase gamma (POLG1) gene. Parkin (PARK2)
gene mutations are responsible for juvenile parkinsonism, and possible
peripheral nervous system involvement has been reported. Rarely, an association
of parkinsonism with PN may be encountered in other neurodegenerative diseases
such as fragile X-associated tremor and ataxia syndrome related to premutation
CGG repeat expansion in the fragile X mental retardation (FMR1) gene,
Machado-Joseph disease related to an abnormal CAG repeat expansion in ataxin-3
(ATXN3) gene, Kufor-Rakeb syndrome caused by mutations in ATP13A2 gene, or in
hereditary systemic disorders such as Gaucher disease due to mutations in the
β-glucocerebrosidase (GBA) gene and Chediak-Higashi syndrome due to LYST gene
mutations. This article reviews conditions in which PN may coexist with
parkinsonism. |
The pathogen Fusarium graminearum affects what type of plant species? | Fusarium graminearum is a broad host pathogen threatening cereal crops in temperate regions around the world. | The fungal pathogens Fusarium graminearum and F. culmorum cause ear blight
disease on cereal crops worldwide. The disease lowers both grain quality and
grain safety. Disease prevalence is increasing due to changes in cropping
practices and the difficulties encountered by plant breeders when trying to
introgress the polygene-based resistance. The molecular basis of resistance to
Fusarium ear blight in cereal species is poorly understood. This is primarily
due to the large size of cereal genomes and the expensive resources required to
undertake gene function studies in cereals. We therefore explored the
possibility of developing various model floral infection systems that would be
more amenable to experimental manipulation and high-throughput gene function
studies. The floral tissues of tobacco, tomato, soybean and Arabidopsis were
inoculated with Fusarium conidia and this resulted in disease symptoms on
anthers, anther filaments and petals in each plant species. However, only in
Arabidopsis did this initial infection then spread into the developing siliques
and seeds. A survey of 236 Arabidopsis ecotypes failed to identify a single
genotype that was extremely resistant or susceptible to Fusarium floral
infections. Three Arabidopsis floral mutants that failed to develop anthers
and/or functional pollen (i.e. agamous-1, apetala1-3 and dad1) were
significantly less susceptible to Fusarium floral infection than wild type.
Deoxynivalenol (DON) mycotoxin production was also detected in Fusarium-infected
flowers at >1 ppm. This novel floral pathosystem for Arabidopsis appears to be
highly representative of a serious cereal crop disease. Species of the necrotrophic fungal pathogen Fusarium that cause head blight and
crown rot of cereals including wheat also infect a number of alternative host
plants. This raises the prospect of more damaging pathogen strains originating
and persisting as highly successful saprophytes on hosts other than wheat. The
immediate impact on pathogenic (aggressiveness) and saprophytic (growth rate and
fecundity) behaviour of six isolates with low, moderate or high initial
aggressiveness was examined in two species of Fusarium after their passage
through 10 alternative plant hosts. One passage through alternative hosts
significantly reduced the pathogenic fitness of most isolates, but this change
was not associated with a concomitant change in their overall saprophytic
behaviour. The overall weak association between aggressiveness, fecundity and
growth rate both before and after passage through the alternative hosts indicate
that pathogenic and saprophytic fitness traits may be independently controlled
in both Fusarium species. Thus, there was no trade-off between pathogenic and
saprophytic fitness in these necrotrophic plant pathogens. BACKGROUND: Fusarium species cause Fusarium head blight (FHB) and other
important diseases of cereals. The causal agents produce trichothecene
mycotoxins such as deoxynivalenol (DON). The dicotyledonous model species
Arabidopsis thaliana has been used to study Fusarium-host interactions but it is
not ideal for model-to-crop translation. Brachypodium distachyon (Bd) has been
proposed as a new monocotyledonous model species for functional genomic studies
in grass species. This study aims to assess the interaction between the most
prevalent FHB-causing Fusarium species and Bd in order to develop and exploit Bd
as a genetic model for FHB and other Fusarium diseases of wheat.
RESULTS: The ability of Fusarium graminearum and Fusarium culmorum to infect a
range of Bd tissues was examined in various bioassays which showed that both
species can infect all Bd tissues examined, including intact foliar tissues. DON
accumulated in infected spike tissues at levels similar to those of infected
wheat spikes. Histological studies revealed details of infection, colonisation
and host response and indicate that hair cells are important sites of infection.
Susceptibility to Fusarium and DON was assessed in two Bd ecotypes and revealed
variation in resistance between ecotypes.
CONCLUSIONS: Bd exhibits characteristics of susceptibility highly similar to
those of wheat, including susceptibility to spread of disease in the spikelets.
Bd is the first reported plant species to allow successful infection on intact
foliar tissues by FHB-causing Fusarium species. DON appears to function as a
virulence factor in Bd as it does in wheat. Bd is proposed as a valuable model
for undertaking studies of Fusarium head blight and other Fusarium diseases of
wheat. Fusarium graminearum is an important plant pathogen that causes head blight of
major cereal crops. The fungus produces mycotoxins that are harmful to animal
and human. In this study, a systematic analysis of 17 phenotypes of the mutants
in 657 Fusarium graminearum genes encoding putative transcription factors (TFs)
resulted in a database of over 11,000 phenotypes (phenome). This database
provides comprehensive insights into how this cereal pathogen of global
significance regulates traits important for growth, development, stress
response, pathogenesis, and toxin production and how transcriptional regulations
of these traits are interconnected. In-depth analysis of TFs involved in sexual
development revealed that mutations causing defects in perithecia development
frequently affect multiple other phenotypes, and the TFs associated with sexual
development tend to be highly conserved in the fungal kingdom. Besides providing
many new insights into understanding the function of F. graminearum TFs, this
mutant library and phenome will be a valuable resource for characterizing the
gene expression network in this fungus and serve as a reference for studying how
different fungi have evolved to control various cellular processes at the
transcriptional level. Fusarium graminearum is a toxigenic fungal pathogen that causes Fusarium head
blight (FHB) and crown rot on cereal crops worldwide. This fungus also causes
damping-off and crown and root rots at the early stage of crop development in
soybean cultivated in North and South America. Several F. graminearum genes were
investigated for their contribution to FHB in cereals but no inherent study is
reported for the dicotyledonous soybean host. In this study we determined the
disease severity on soybean seedlings of five single gene disrupted mutants of
F. graminearum, previously characterized in wheat spike infection. Three of
these mutants are impaired on a specific function as the production of
deoxynivalenol (DON, Δtri5), lipase (ΔFgl1), and xylanase (Δxyl03624), while the
remaining two are MAP kinase mutants (ΔFgOS-2, Δgpmk1), which are altered in
signaling pathways. The mutants that were reduced in virulence (Δtri5, ΔFgl1,
and ΔFgOS-2) or are avirulent (Δgpmk1) on wheat were correspondently less
virulent or avirulent in soybean seedlings, as shown by the extension of lesions
and seedling lengths. The Δxyl03624 mutant was as virulent as the wild type
mirroring the behavior observed in wheat. However, a different ranking of
symptom severity occurred in the two hosts: the ΔFgOS-2 mutant, that infects
wheat spikelets similarly to Δtri5 and ΔFgl1 mutants, provided much reduced
symptoms in soybean. Differently from the other mutants, we observed that the
ΔFgOS-2 mutant was several fold more sensitive to the glyceollin phytoalexin
suggesting that its reduced virulence may be due to its hypersensitivity to this
phytoalexin. In conclusion, lipase and DON seem important for full disease
symptom development in soybean seedlings, OS-2 and Gpmk1 MAP kinases are
essential for virulence, and OS-2 is involved in conferring resistance to the
soybean phytoalexin. The cereal pathogen Fusarium graminearum threatens food and feed production
worldwide. It reduces the yield and poisons the remaining kernels with
mycotoxins, notably deoxynivalenol (DON). We analyzed the importance of
gamma-aminobutanoic acid (GABA) metabolism for the life cycle of this fungal
pathogen. GABA metabolism in F. graminearum is partially regulated by the global
nitrogen regulator AreA. Genetic disruption of the GABA shunt by deletion of two
GABA transaminases renders the pathogen unable to utilize the plant stress
metabolites GABA and putrescine. The mutants showed increased sensitivity
against oxidative stress, GABA accumulation in the mycelium, downregulation of
two key enzymes of the TCA cycle, disturbed potential gradient in the
mitochondrial membrane and lower mitochondrial oxygen consumption. In contrast,
addition of GABA to the wild type resulted in its rapid turnover and increased
mitochondrial steady state oxygen consumption. GABA concentrations are highly
upregulated in infected wheat tissues. We conclude that GABA is metabolized by
the pathogen during infection increasing its energy production, whereas the
mutants accumulate GABA intracellularly resulting in decreased energy
production. Consequently, the GABA mutants are strongly reduced in virulence
but, because of their DON production, are able to cross the rachis node. Fusarium head blight (FHB) of small cereals is a disease of global importance
with regard to economic losses and mycotoxin contamination harmful to human and
animal health. In Germany, FHB is predomitly associated with wheat and F.
graminearum is recognised as the major causal agent of the disease, but little
is known about FHB of barley. Monitoring of the natural occurrence of FHB on
Bavarian barley revealed differences for individual Fusarium spp. in incidence
and severity of grain infection between years and between spring and winter
barley. Parallel measurement of fungal DNA content in grain and mycotoxin
content suggested the importance of F. graminearum in winter barley and of F.
langsethiae in spring barley for FHB. The infection success of these two species
was associated with certain weather conditions and barley flowering time.
Inoculation experiments in the field revealed different effects of five Fusarium
spp. on symptom formation, grain yield and mycotoxin production. A significant
association between fungal infection of grain and mycotoxin content was observed
following natural or artificial infection with the type B trichothecene producer
F. culmorum, but not with the type A trichothecene-producing species F.
langsethiae and F. sporotrichioides. Trichothecene type A toxin contamination
also occurred in the absence of significant damage to grain and did not
necessarily promote fungal colonisation. Fusarium graminearum is a broad host pathogen threatening cereal crops in
temperate regions around the world. To better understand how F. graminearum
adapts to different hosts, we have performed a comparison of the transcriptome
of a single strain of F. graminearum during early infection (up to 4 d
post-inoculation) of barley, maize, and wheat using custom oligomer microarrays.
Our results showed high similarity between F. graminearum transcriptomes in
infected wheat and barley spike tissues. Quantitative RT-PCR was used to
validate the gene expression profiles of 24 genes. Host-specific expression of
genes was observed in each of the three hosts. This included expression of
distinct sets of genes associated with transport and secondary metabolism in
each of the three crops, as well as host-specific patterns for particular gene
categories such as sugar transporters, integral membrane protein PTH11-like
proteins, and chitinases. This study identified 69 F. graminearum genes as
preferentially expressed in developing maize kernels relative to wheat and
barley spikes. These host-specific differences showcase the genomic flexibility
of F. graminearum to adapt to a range of hosts. Fusarium graminearum is the fungal pathogen that causes globally important
diseases of cereals and produces mycotoxins such as deoxynivalenol (DON). Owing
to the dearth of available sources of resistance to Fusarium pathogens,
characterization of novel genes that confer resistance to mycotoxins and
mycotoxin-producing fungi is vitally important for breeding resistant crop
varieties. In this study, a wheat methionyl-tRNA synthetase (TaMetRS) gene was
identified from suspension cell cultures treated with DON. It shares conserved
aminoacylation catalytic and tRNA anticodon binding domains with human MetRS and
with the only previously characterized plant MetRS, suggesting that it functions
in aminoacylation in the cytoplasm. However, the TaMetRS comprises a typical
nuclear localization signal and cellular localization studies with a
TaMetRS::GFP fusion protein showed that TaMetRS is localized in the nucleus.
Expression of TaMetRS was activated by DON treatment and by infection with a
DON-producing F. graminearum strain in wheat spikes. No such activation was
observed following infection with a non-DON-producing F. graminearum strain.
Expression of TaMetRS in Arabidopsis plants conferred significant resistance to
DON and F. graminearum. These results indicated that this DON-activated TaMetRS
gene may encode a novel type of MetRS in plants that has a role in defense and
detoxification. |
List viral vectors used in gene therapy. | adeno-associated viruses
lentiviruses
herpes simplex viral vector | This study examined the efficacy of gene therapy of lung adenocarcinoma using
specifically controlled type I herpes simplex virus recombit vector
expressing Gibbon ape leukemia virus membrane fusion glycoprotein gene
(GALV.fus). Recombit HSV-I plasmid carrying target transgene was constructed,
and recombit viral vector was generated in Vero cells using Lipofectamine
transfection. Viral vector was introduced into lung adenocarcinoma A549 cells or
human fetal fibroblast HFL-I GNHu 5 cells, or inoculated into human lung
adenocarcinoma xenografts in nude mice. The anti-tumor and cytotoxic effects of
GALV-FMG, the transgene, were examined in these cell and animal models.
Expression of GALV-FMG in xenographs achieved 100 % tumorigenicity. Recombit
HSV-I viral vector also exhibited significant tumor cell killing effect in
vitro. Relative survival rates of tumor cells treated with GALV-FMG or control
vectors were, respectively, 20 and 70 %. GALV.fus has a potent anti-tumor effect
against lung cancer both in vitro and in vivo. This anti-tumor potential
provides foundation for further studies with this vector. Over the last five years, the number of clinical trials involving AAV
(adeno-associated virus) and lentiviral vectors continue to increase by about
150 trials each year. For continued success, AAV and lentiviral expression
cassettes need to be designed to meet each disease's specific needs. This review
discusses how viral vector expression cassettes can be engineered with elements
to enhance target specificity and increase transgene expression. The key
differences relating to target specificity between ubiquitous and
tissue-specific promoters are discussed, as well as how endogenous miRNAs and
their target sequences have been used to restrict transgene expression.
Specifically, relevant studies indicating how cis-acting elements such as
introns, WPRE, polyadenylation signals, and the CMV enhancer are highlighted to
show their utility for enhancing transgene expression in gene therapy
applications. All discussion bears in mind that expression cassettes have space
constraints. In conclusion, this review can serve as a menu of vector genome
design elements and their cost in terms of space to thoughtfully engineer viral
vectors for gene therapy. Author information:
(1)Graduate Program in Molecular Virology and Microbiology, University of
Pittsburgh, School of Medicine, Pittsburgh, PA, 15213, USA. [email protected].
(2)Department of Ophthalmology, University of Pittsburgh School of Medicine,
Room 1020 EEI, 203 Lothrop Street, Pittsburgh, PA, 15213, USA.
[email protected].
(3)Department of Anesthesiology, New Jersey Medical School, Rutgers, State
University of New Jersey, 185 S. Orange Ave., MSB, F-548, Newark, NJ, 07103,
USA. [email protected].
(4)Department of Anesthesiology, University of Miami Miller School of Medicine,
Miami, FL, 33136, USA. [email protected].
(5)Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, USA.
[email protected].
(6)Microbiology and Molecular Genetics, University of Pittsburgh School of
Medicine, 424 Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA, 15219,
USA. [email protected].
(7)Department of Anesthesiology, University of Miami Miller School of Medicine,
Miami, FL, 33136, USA. [email protected].
(8)Department of Anesthesiology, University of Miami Miller School of Medicine,
Miami, FL, 33136, USA. [email protected].
(9)Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA.
[email protected].
(10)Department of Anesthesiology, New Jersey Medical School, Rutgers, State
University of New Jersey, 185 S. Orange Ave., MSB, F-548, Newark, NJ, 07103,
USA. [email protected].
(11)Department of Anesthesiology, New Jersey Medical School, Rutgers, State
University of New Jersey, 185 S. Orange Ave., MSB, F-548, Newark, NJ, 07103,
USA. [email protected].
(12)Department of Cell Biology & Molecular Medicine, New Jersey Medical School,
Rutgers, State University of New Jersey, Newark, NJ, 07103, USA.
[email protected].
(13)Department of Neurology & Neuroscience, New Jersey Medical School, Rutgers,
State University of New Jersey, Newark, NJ, 07103, USA. [email protected].
(14)Department of Physiology & Pharmacology, New Jersey Medical School, Rutgers,
State University of New Jersey, Newark, NJ, 07103, USA. [email protected].
(15)Graduate Program in Molecular Virology and Microbiology, University of
Pittsburgh, School of Medicine, Pittsburgh, PA, 15213, USA.
[email protected].
(16)Department of Ophthalmology, University of Pittsburgh School of Medicine,
Room 1020 EEI, 203 Lothrop Street, Pittsburgh, PA, 15213, USA.
[email protected].
(17)Microbiology and Molecular Genetics, University of Pittsburgh School of
Medicine, 424 Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA, 15219,
USA. [email protected].
(18)Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, USA.
[email protected].
(19)Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA.
[email protected].
(20)Department of Pharmacology, University of Minnesota, 9-177 Weaver Densford
Hall, 308 Harvard Street, Minneapolis, MN, 55455, USA. [email protected].
(21)Department of Anesthesiology, University of Miami Miller School of Medicine,
Miami, FL, 33136, USA. [email protected]. Adenoviral vectors have proven to be valuable resources in the development of
novel therapies aimed at targeting pathological conditions of the central
nervous system, including Alzheimer's disease and neoplastic brain lesions. Not
only can some genetically engineered adenoviral vectors achieve remarkably
efficient and specific gene delivery to target cells, but they also may act as
anticancer agents by selectively replicating within cancer cells.Due to the
great interest in using adenoviral vectors for various purposes, the need for a
comprehensive protocol for viral vector production is especially apparent. Here,
we describe the process of generating an adenoviral vector in its entirety,
including the more complex process of adenoviral fiber modification to restrict
viral tropism in order to achieve more efficient and specific gene delivery. Author information:
(1)Department of Translational Science & Molecular Medicine, Michigan State
University, 333 Bostwick Ave., NE, Grand Rapids, MI, 49503-2532, USA.
(2)MD/PhD Program, Michigan State University, Grand Rapids, MI, USA.
(3)Neuroscience Graduate Program, Michigan State University, Grand Rapids, MI,
USA.
(4)Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH, USA.
(5)Translational Science and Molecular Medicine, Michigan State University,
College of Human Science, 333 Bostwick Ave., NE, Grand Rapids, MI, 49503-2532,
USA.
(6)Department of Translational Science & Molecular Medicine, Michigan State
University, 333 Bostwick Ave., NE, Grand Rapids, MI, 49503-2532, USA.
[email protected]. |
Is dexamethasone recommended for treatment of intracerebral hemorrhage? | No. Dexamethasone and other glucocorticoids should be avoided for treatment of intracerebral hemorrhage because they do not improve patient outcome and are associated with increased risk of side effects. | To evaluate the efficacy of dexamethasone for treatment of primary
supratentorial intracerebral hemorrhage, we studied 93 patients 40 to 80 years
old, using a double-blind randomized block design. After the subjects were
stratified according to their level of consciousness (Glasgow Coma Scale), those
with objectively documented primary supratentorial intracerebral hemorrhage were
randomly assigned to either dexamethasone or placebo. For ethical reasons, three
interim analyses were planned, to permit early termination of the trial if one
study group did better than the other. During the third interim analysis, the
death rate at the 21st day was identical in the two groups (dexamethasone vs.
placebo, 21 of 46 vs. 21 of 47; chi-square = 0.01, P = 0.93). In contrast, the
rate of complications (mostly infections and complications of diabetes) was much
higher in the dexamethasone group (chi-square = 10.89, P less than 0.001),
leading to early termination of the study. In the light of the absence of a
demonstrable beneficial effect and the presence of a significant harmful effect,
current practices of using dexamethasone for treatment of primary supratentorial
hemorrhage should be reconsidered. BACKGROUND: Corticosteroids, particularly dexamethasone, are commonly used for
treatments in patients with subarachnoid haemorrhage (SAH) and primary
intracerebral haemorrhage (PICH) despite the lack of evidence.
OBJECTIVES: This review aimed: (1) to determine whether corticosteroid therapy
reduces the proportion of patients who die or have a poor outcome at one to six
months after the onset of SAH or PICH; (2) to determine whether corticosteroid
therapy reduces the frequency of delayed cerebral ischaemia (DCI) in patients
with SAH; (3) to determine the frequency of adverse effects of corticosteroid
therapy in patients with SAH or PICH within six months of the onset of the
event.
SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last
searched November 2003). In addition, we searched MEDLINE (1966 to March 2004)
and EMBASE (1980 to March 2004), and searched reference lists of relevant
studies identified. We also made an attempt to identify any relevant ongoing and
published or unpublished studies by contacting trialists and pharmaceutical
companies.
SELECTION CRITERIA: We sought to identify all randomised or quasi-randomised
clinical trials of corticosteroid therapy, in patients with SAH or PICH, that
have a placebo or standard strategy arm as control. Patients of any age and
either gender with clinically (bed-side) diagnosed PICH and cerebrospinal fluid
documented SAH were included in the analysis. The data were analysed both
separately and combined for computed tomography (CT)/magnetic resoce imaging
(MRI)/autopsy/angiography verified patients.
DATA COLLECTION AND ANALYSIS: Data extracted from eligible clinical trials
included: (1) death and poor outcome (death, severe disability, or vegetative
state) within the first one to six months of the event onset (primary outcomes);
(2) development of delayed cerebral ischaemia (as defined by the trialists) in
patients with SAH; and (3) adverse effects of the treatment during the scheduled
treatment or follow-up period (secondary outcomes). A pooled estimate of the
effect size was computed, and the test for heterogeneity between trial results
was carried out using The Cochrane Collaboration's Review Manager software,
RevMan 4.2. Intention-to-treat analysis was carried out whenever possible.
MAIN RESULTS: Eight trials that fulfilled the eligibility criteria were
identified, with a total of 256 randomised patients in three SAH trials, and 206
patients in five PICH trials. The studies differed substantially with regard to
the study populations and drugs, and methodological quality. The number of
patients allocated to either hydrocortisone or fludrocortisone acetate treatment
in patients with SAH, or to dexamethasone treatment in patients with PICH, was
too small to make any definitive conclusions (confidence intervals were wide for
any of the outcome estimates).
AUTHORS' CONCLUSIONS: Overall, there is no evidence of a beneficial or adverse
effect of corticosteroids in patients with either SAH or PICH. Confidence
intervals are wide and include clinically significant effects in both
directions. |
What happens upon disruption of a TAD boundary? | rewiring occurred only if the variant disrupted a ctcf-associated boundary domain . of a tad boundary causes ectopic chromosomal contacts and long-range transcriptional misregulation. . of topological chromatin domains cause pathogenic rewiring of gene-enhancer interactions . | In eukaryotes transcriptional regulation often involves multiple long-range
elements and is influenced by the genomic environment. A prime example of this
concerns the mouse X-inactivation centre (Xic), which orchestrates the
initiation of X-chromosome inactivation (XCI) by controlling the expression of
the non-protein-coding Xist transcript. The extent of Xic sequences required for
the proper regulation of Xist remains unknown. Here we use chromosome
conformation capture carbon-copy (5C) and super-resolution microscopy to analyse
the spatial organization of a 4.5-megabases (Mb) region including Xist. We
discover a series of discrete 200-kilobase to 1 Mb topologically associating
domains (TADs), present both before and after cell differentiation and on the
active and inactive X. TADs align with, but do not rely on, several domain-wide
features of the epigenome, such as H3K27me3 or H3K9me2 blocks and
lamina-associated domains. TADs also align with coordinately regulated gene
clusters. Disruption of a TAD boundary causes ectopic chromosomal contacts and
long-range transcriptional misregulation. The Xist/Tsix sense/antisense unit
illustrates how TADs enable the spatial segregation of oppositely regulated
chromosomal neighbourhoods, with the respective promoters of Xist and Tsix lying
in adjacent TADs, each containing their known positive regulators. We identify a
novel distal regulatory region of Tsix within its TAD, which produces a long
intervening RNA, Linx. In addition to uncovering a new principle of
cis-regulatory architecture of mammalian chromosomes, our study sets the stage
for the full genetic dissection of the X-inactivation centre. Author information:
(1)Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195
Berlin, Germany; Institute for Medical and Human Genetics, Charité
Universitätsmedizin Berlin, 13353 Berlin, Germany.
(2)Institute for Medical and Human Genetics, Charité Universitätsmedizin Berlin,
13353 Berlin, Germany.
(3)Medical Genetics Unit, Policlinico Tor Vergata University Hospital, 00133
Rome, Italy.
(4)Institute of Human Genetics Biozentrum, Julius Maximilian University of
Würzburg, 97070 Würzburg, Germany.
(5)Medical Genetics Department, Istanbul Medical Faculty, Istanbul University,
34093 Istanbul, Turkey.
(6)Department of Pediatrics, School of Medicine, University of Utah, Salt Lake
City, UT 84108, USA.
(7)Instituto de Genética Médica y Molecular (INGEMM), IdiPAZ, Hospital
Universitario La Paz, 28046 Madrid, Spain; U753 Centro de Investigación
Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III,
28046 Madrid, Spain.
(8)Service de Génétique, C.H.U. de Poitiers, 86021 Poitiers, France.
(9)Department Developmental Genetics, Max Planck Institute for Molecular
Genetics, 14195 Berlin, Germany.
(10)Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195
Berlin, Germany.
(11)Department of Computational Molecular Biology, Max Planck Institute for
Molecular Genetics, 14195 Berlin, Germany.
(12)Genomics Division, MS 84-171, Lawrence Berkeley National Laboratory,
Berkeley, CA 94720, USA.
(13)Max Planck Institute for Molecular Genetics, Sequencing Core Facility, 14195
Berlin, Germany.
(14)Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195
Berlin, Germany; Berlin-Brandenburg Center for Regenerative Therapies (BCRT),
Charité Universitätsmedizin Berlin, 13353 Berlin, Germany.
(15)Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195
Berlin, Germany; Institute for Medical and Human Genetics, Charité
Universitätsmedizin Berlin, 13353 Berlin, Germany; Berlin-Brandenburg Center for
Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, 13353 Berlin,
Germany.
(16)Genomics Division, MS 84-171, Lawrence Berkeley National Laboratory,
Berkeley, CA 94720, USA; U.S. Department of Energy Joint Genome Institute,
Walnut Creek, CA 94598, USA; School of Natural Sciences, University of
California, Merced, CA 95343, USA.
(17)Max Planck Institute for Molecular Genetics, RG Development & Disease, 14195
Berlin, Germany; Institute for Medical and Human Genetics, Charité
Universitätsmedizin Berlin, 13353 Berlin, Germany; Berlin-Brandenburg Center for
Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, 13353 Berlin,
Germany. Electronic address: [email protected]. |
List the classical symptoms of the Moschcowitz syndrome (Thrombotic thrombocytopenic purpura). | The typical manifestations of Moschocowitz syndrome (Thrombotic-thrombocytopenic purpura) are:
1) thrombocytopenia,
2) haemolysis,
3) fever,
4) coma and
5) renal failure. | PIP: Thrombotic thrombocytopenic purpura (TTP) is a syndrome that occurs mainly
in adults with multiorgan microvascular thrombosis consisting of
thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, renal
involvement, and fever. The female to male ratio is 3:2, and peak incidence
occurs in the 3rd decade of life. Clinical signs are the consequence of hyaline
thrombosis and occlusion of capillaries and arterioles. Renal ailment manifests
itself in hematuria and proteinuria with azotemia and even overt renal failure.
In severe disease, azotemia is typical of hemolytic uremic syndrome (HUS). TTP
was first described in 1925 by Moschcowitz. The clinical picture of TTP consists
of a prodromal phase, a viruslike disease occurring in up to 40% of patients.
60% have neurologic disturbances, 90% have purpura initially, and fever occurs
in all. Anemia is often severe with hemoglobin values of 7-9 gm/dl, renal
involvement in 90%, and renal failure in 40-80% of patients. Clinical variants
include the acute and fulmit variety mortality, the chronic form, and the
relapsing form. Predisposing factors and triggering agents are autosomal
recessive inherited traits in acute idiopathic TTP, systemic diseases, tumor
antigens, pregcy and puerperium, viruses (endotoxins for HUS), and possibly
oral contraceptives and hypertension. Therapy includes corticosteroids
(prednisone 100-400 mg/day); heparin for postpartum HUS; and antiplatelet agents
(Dextran 70, aspirin, and dipyridamole in high doses). The infusion of PGI2 is
controversial; splenectomy is also questionable; and vincristine, azathioprine,
and cyclophosphamide have unproven efficacy. Fresh-frozen plasma exchange is the
method of choice as it produces survival in 90%. Others are iv immunoglobulins,
vitamin E, and dialysis and renal transplant. Platelet transfusions are
contraindicated because of sudden death and decreased survival. In addition to the typical manifestations of thrombotic-thrombocytopenic purpura
like thrombocytopenia, haemolysis, fever, coma and renal failure, signs of a
beginning DIC could be seen in a patient after abdominal surgery. Haemostatic,
cardiovascular and respiratory data are presented. Pulmonary angiography by
using a Swan-Ganz-catheter revealed multiple filling defects reversible with
therapy. Treatment with fresh whole blood aggravated thrombocytopenia. Daily
infusions of fresh frozen plasma combined with heparinisation and antithrombin
III because of DIC, induced haematologic remission. Renal failure and cerebral
symptoms could not be influenced. Diagnosis, monitoring and therapy are
discussed. Moschcowitz syndrome or thrombotic thrombocytopenic purpura is a rare disorder
with a poor prognosis. This syndrome is characterized by a microangiopathic
hemolytic anemia with thrombocytopenia, neurologic symptoms and renal disease.
The vascular lesion consists of disseminated hyaline thrombi in the
microvasculature composed mainly of platelet aggregates. The mechanisms are
still poorly understood and are probably multiple. Recent data focus on an
abnormal endothelial synthesis of prostacyclin and the presence of a factor (or
the reduction of its inhibitor) in plasma able to induce intravascular
disseminated platelet aggregation. The most efficient therapy seems to be
infusions of fresh plasma with or without plasma exchange. Moschcowitz's syndrome is a rare condition with poor prognosis. It is
characterized by a microangiopathic haemolytic anaemia associated with
thrombocytopenia, neurological symptoms and renal involvement. The vascular
lesions consist of hyaline microthrombi, predomitly made up of platelet
aggregates, disseminated in the smaller vessels. The physiopathological
mechanisms are still poorly understood and probably multiple. Recent studies
have demonstrated abnormalities in the endothelial synthesis of prostacyclin,
and in many cases the lack of a plasma factor has been held responsible for
intravascular disseminated platelet aggregation. The latest therapeutic attempts
suggest that the most effective treatment probably is fresh plasma transfusions
associated or not with plasma exchanges. ANAMNESIS AND CLINICAL FINDINGS: A 75-year-old woman with a history of recurrent
ischemic cerebral events was admitted with acute unspecific neurological
symptoms and fever.
EXAMINATION: Intracerebral hemorrhage due to hypertension and antithrombotic
therapy with ticlopidine was ruled out with cranial computed tomography.
Laboratory findings on admission included thrombocytopenia (12/nl), renal
insufficiency (serum creatinine 1.6 mg/dl) and LDH elevation (1,218 U/l). The
hemoglobin on admission was normal.
THERAPY AND CLINICAL COURSE: In the presence of rapidly declining hemoglobin
values and fragmentation of red cells thrombotic-thrombocytopenic purpura (TTP)
was diagnosed and the patient received fresh frozen plasma. Shortly after the
plasma infusion the patient's condition deteriorated rapidly showing clinical
signs of an allergic shock. In the sequel of 24 to 48 hours the patient
developed renal failure, severe anemia and the thrombocyte count fell to 5/nl.
The patient was mechanically ventilated during the next 48 hours and needed
intravenous catecholamines. Even after restoration of spontaneous respiration
and cessation of pharmacological sedation the patient remained comatose. Cranial
computed tomography on the fourth day after admission showed multiple infarction
syndrome. The patient died on the ninth day after admission in status
epilepticus which could not be stopped with pharmacological means.
CONCLUSIONS: The combination of neurological symptoms, thrombocytopenia, fever,
renal failure and hemolytic anemia in a patient taking ticlopidine points to a
diagnosis of TTP. The high mortality of TTP can probably only be reduced by
early plasmapheresis. BACKGROUND: Thrombotic thrombocytopenic purpura (TTP), in 1924 first described
by Moschcowitz, is a clinically heterogeneous syndrome associated with
thrombocytopenia, Coombs-negative hemolytic anemia, neurologic changes, renal
impairment, and fever. TTP is found after various bacterial or viral infectious
diseases, autoimmune diseases and also in association with different drugs.
PATHOGENESIS: After initial endothelial cell injury unusually large von
Willebrand factors (vWF) are found in plasma of patients with thrombotic
thrombocytopenic purpura. Because of impaired proteolysis these large forms lead
to thrombosis of the small vessels. The microangiopathy is followed by
mechanical destruction of red cells. In peripheral blood smears these
fragmentocytes are important for diagnosis and clinical course.
THERAPY: The therapy of choice is plasma exchange against fresh frozen plasma,
whereupon the mortality could be dramatically reduced in the past decades. In
case of treatment resistance to plasma exchange there exists no common treatment
schedule. One therapy option is immunosuppressive treatment with corticosteroids
and vincristine. In case of chronic relapsing TTP splenectomy should be
discussed. In spite of severe thrombocytopenia substitution of thrombocytes is
contraindicated. BACKGROUND: Severe deficiency of von Willebrand factor-cleaving protease
(ADAMTS-13) activity (<5% of normal) is specific for classical thrombotic
thrombocytopenic purpura (TTP), a disorder presenting with thrombocytopenia,
microangiopathic haemolytic anaemia and often with organ dysfunction such as
neurological symptoms, renal failure, and fever. A certain, though according to
several case series, variable percentage of patients with clinically diagnosed
TTP and most patients with other forms of thrombotic icroangiopathies (TMA) do
not show severe ADAMTS-13 deficiency.
METHODS: We determined ADAMTS-13 activity in 508 plasma samples of 309 patients
referred to our laboratory in 2001 and 2002. Plasma samples with ADAMTS-13
activity <5% were additionally tested for the presence of inhibitory antibodies.
Patients were assigned to ten predefined clinical categories according to
information provided in the referral letter (TMA not specified; TMA associated
with neoplasia or chemotherapy; TMA following haematopoietic stem cell
transplantation; TMA with additional disorder; idiopathic TTP;
haemolytic-uraemic syndrome (HUS) not specified; HUS with diarrhoea prodrome;
atypical HUS; other haematological disorder; no clinical information available).
RESULTS: We detected 50 (16%) patients with severe ADAMTS-13 deficiency.
Forty-four (88%) of these patients had been classified as idiopathic TTP, 2 as
neoplasia- or chemotherapy-associated, and 4 as non-specified TMA. Among the
patients labelled as acute idiopathic TTP, the prevalence of severe ADAMTS-13
deficiency was 63% (44/70). Inhibitory antibodies were found in 31 (62%)
patients with ADAMTS-13 activity <5%. Of the 44 patients with acute idiopathic
TTP, at initial presentation or at relapse, with ADAMTS-13 activity <5%, 11 were
identified to have (probable) constitutional severe ADAMTS-13 deficiency.
CONCLUSION: Severe ADAMTS-13 deficiency is found in about 60% of patients
diagnosed with idiopathic TTP but in none of 111 diagnosed with HUS. Plasma
ADAMTS-13 activity <5%, however, does not identify all patients clinically
diagnosed with TTP. Detection of inhibitory antibodies against ADAMTS-13 helps
to differentiate between acquired and constitutional forms of TTP, which may be
important for treatment strategies. Thrombotic thrombocytopenic purpura (TTP) is a rare microangiopathic disorder
with high morbidity and significant mortality. The primary form of TTP is caused
by severe deficiency, acquired or hereditary, of the von Willebrand factor
cleaving protease (VWF-CP), ADAMTS-13. Because TTP occurs less frequently in
children, general pediatricians are not well informed about the spectrum of
clinical symptoms and altered laboratory values, increasing the risk of
nondiagnosis and possible fatal outcome. If renal involvement is present, the
condition can easily be misdiagnosed as hemolytic-uremic syndrome (HUS). We
present a case series of children with severe VWF-CP deficiency with emphasis on
the clinical heterogeneity responsible for misdiagnosis and inappropriate
treatment. The inherited form may involve onset of symptoms ranging from
isolated thrombocytopenia to the full clinical picture characteristic of
classical TTP. The most common assumed diagnoses of oligosymptomatic forms are
immune thrombocytopenia (ITP) and Evans syndrome, respectively. Accordingly,
this article is directed towards pediatricians on neonatal and intensive care
units, as well as their colleagues specializing in nephrology, hematology, and
neurology. The clinical syndrome of fever, neurologic abnormalities, renal impairment with
laboratory findings of thrombocytopenic and microangiopathic hemolytic anemia is
seen in thrombotic thrombocytopenic purpura (TTP) and a variety of disorders
associated with thrombotic microangiopathy (TMA). With improved understanding of
the pathogenesis of the perturbed metabolic pathway of von Willebrand factor in
TTP, the classic Moschcowitz syndrome, now more accurately referred to as
idiopathic TTP, can be distinguished from other TMAs. The distinguishing
features are useful not only in providing an accurate diagnosis but also help to
determine the best therapeutic strategy. Thrombotic microangiopathies are characterized by platelet activation,
endothelial damage, hemolysis and microvascular occlusion. This group of
diseases is primary represented by thrombotic thrombocytopenic purpura (TTP) and
hemolytic uremic syndrome (HUS). Patients present with microangiopathic
hemolytic anemia and thrombocytopenia as well as occlusion-related organ
ischemia to a variable degree. A deficiency of the metalloprotease ADAMTS-13 is
a major risk for acute disease manifestation as this is a regulator of unusually
large von Willebrand factor (vWF) multimers, which are extremely adhesive and
secreted by endothelial cells. In classical TTP an ADAMTS-13 activity below 5%
is specific, whereas in other forms of thrombotic microangiopathies activity of
ADAMTS-13 ranges from very low to normal. Symptoms of different forms of
thrombotic microangiopathy are frequently overlapping and a clear classification
according to clinical criteria is often difficult. Due to a high mortality,
particularly of TTP, immediate diagnosis and therapy are essential. In this
article two cases of thombotic microangiopathy after cardiac surgery are
reported. After exclusion of TTP and HUS as well as other etiologies of
thrombotic microangiopathy a relationship between the use of extracorporeal
circulation and the pathogenesis of thrombotic microangiopathy is assumed. Thrombotic thrombocytopenic purpura (TTP, Moschcowitz disease) is characterized
by thrombotic microangiopathy leading to microvascular occlusion and ischemic
dysfunction of various organs including the brain. In the course of the rare
disease most patients develop neurological symptoms of varying severity and
characteristics. The case presented is that of a 34-year-old female patient with
profound thrombocytopenia, anemia and rapidly progressive neurological
deterioration into coma with normal result of brain imaging. TTP was recognized
on the basis of hematological analysis. The initiated steroid therapy and plasma
exchange failed to prevent the turbulent course of disease in the patient, who
died exhibiting symptoms of multiple organ failure caused by thrombotic
microangiopathy. TTP remains to be a diagnostic challenge, particularly in the
case of atypical symptoms or when neuroimaging and laboratory results are
inconclusive. Before using the corticosteroids and plasma exchange, TTP had a
case fatality rate of approx. 90% (Podolak-Dawidziak, 2013). Nowadays recovery
is possible when vigorous treatment is introduced early in the course of this
disease. |
Is airplane stroke syndrome a common disease. | No. Only 37 cases of stroke during or soon after long-haul flights have been published. A single center study reported that 42 out of 5727 stroke admissions (0.73%) were flight-related strokes. | In the economy class syndrome (ECS) the patient presents a deep venous
thrombosis (DVT) with or without pulmonary thromboembolism (PTE) during or after
a long trip as a result of prolonged immobilization. Economy class stroke
syndrome is an infrequent ECS variant in which ischemic stroke is associated
with a patent foramen ovale (PFO). Few cases have been published in the
literature to date. We present a patient who suffered a PTE and an ischemic
stroke immediately after a transoceanic flight. A 36-year-old woman with no
significant medical or familial history flew economy class from Lima, Peru, to
Madrid, Spain. On disembarkation she presented sudden dyspnea and a depressed
level of consciousness, global aphasia, and right hemiparesis. A pulmonary
scintigraphy showed a PTE and a cranial MRI revealed an ischemic infarct in the
left middle cerebral artery territory. We simultaneously performed a
transesophageal echocardiography and a transcranial Doppler and observed a
massive right-to-left shunt through a PFO. The patient was a heterozygous
carrier of the C46T mutation of coagulation factor XII. The appearance of a
stroke following a long trip is suggestive of paradoxical embolism through a
PFO, mainly if it is associated with a DVT and/or a PTE. The cause of the
initial event, the DVT, could be a prothrombotic state. BACKGROUND AND PURPOSE: Stroke on board aircraft has been reported in
retrospective case series, mainly focusing on economy class stroke syndrome.
Data on the actual incidence, pathogenesis, and prognosis of stroke in
commercial flights are lacking.
METHODS: A prospective registry was designed to include all consecutive patients
referred from an international airport (40 million passengers a year) to our
hospital with a diagnosis of ischemic stroke or transient ischemic attack and
onset of symptoms during a flight or immediately after landing.
RESULTS: Forty-four patients (32 ischemic strokes and 12 transient ischemic
attacks) were included over a 76-month period (January 2008 to April 2014). The
estimated incidence of stroke was 1 stroke in 35 000 flights. Pathogeneses of
stroke or transient ischemic attack were atherothrombotic in 16 (36%), economy
class stroke syndrome in 8 (18%), cardioembolic in 7 (16%), arterial dissection
in 4 (9%), lacunar stroke in 4 (9%), and undetermined in 5 (12%) patients.
Carotid stenosis >70% was found in 12 (27%) of the patients. Overall prognosis
was good, and thrombolysis was applied in 44% of the cases. The most common
reason for not treating patients who had experienced stroke onset midflight was
the delay in reaching the hospital. Only 1 patient with symptom onset during the
flight prompted a flight diversion.
CONCLUSIONS: We found a low incidence of stroke in the setting of air travel.
Economy class stroke syndrome and arterial dissection were well represented in
our sample. However, the main pathogenesis was atherothrombosis with a high
proportion of patients with high carotid stenosis. Only 37 cases of stroke during or soon after long-haul flights have been
published to our knowledge. In this retrospective observational study, we
searched the Royal Melbourne Hospital prospective stroke database and all
discharge summaries from 1 September 2003 to 30 September 2014 for
flight-related strokes, defined as patients presenting with stroke within 14days
of air travel. We hypothesised that a patent foramen ovale (PFO) is an
important, but not the only mechanism, of flight-related stroke. We describe the
patient, stroke, and flight characteristics. Over the study period, 131 million
passengers arrived at Melbourne airport. Our centre admitted 5727 stroke
patients, of whom 42 (0.73%) had flight-related strokes. Flight-related stroke
patients were younger (median age 65 versus 73, p<0.001), had similar stroke
severity, and received intravenous thrombolysis more often than
non-flight-related stroke patients. Seven patients had flight-related
intracerebral haemorrhage. The aetiology of the ischaemic strokes was
cardioembolic in 14/35 (40%), including seven patients with confirmed PFO, one
with atrial septal defect, four with atrial fibrillation, one with endocarditis,
and one with aortic arch atheroma. Paradoxical embolism was confirmed in six
patients. Stroke related to air travel is a rare occurrence, less than one in a
million. Although 20% of patients had a PFO, distribution of stroke aetiologies
was diverse and was not limited to PFO and paradoxical embolism. |
Which R / bioconductor package is used for enrichment analysis of genomic regions? | locus overlap analysis (lola) provides easy and automatable enrichment analysis for genomic region sets, thus facilitating the interpretation of functional genomics and epigenomics data. | Genomic datasets are often interpreted in the context of large-scale reference
databases. One approach is to identify significantly overlapping gene sets,
which works well for gene-centric data. However, many types of high-throughput
data are based on genomic regions. Locus Overlap Analysis (LOLA) provides easy
and automatable enrichment analysis for genomic region sets, thus facilitating
the interpretation of functional genomics and epigenomics data.
AVAILABILITY AND IMPLEMENTATION: R package available in Bioconductor and on the
following website: http://lola.computational-epigenetics.org. |
Which is the major RNA editing enzyme in Drosophila melanogaster? | Adenosine deaminases that act on RNA [adenosine deaminase, RNA specific (ADAR)] catalyze the site-specific conversion of adenosine to inosine in primary mRNA transcripts. The ADAR RNA editing enzyme controls neuronal excitability in Drosophila melanogaster. TIRs were deduced to form dsRNAs as a putative target of ADAR. Genetic Determinants of RNA Editing Levels of ADAR Targets in Drosophila melanogaster. RNA editing usually affects only a fraction of expressed transcripts and there is a vast amount of variation in editing levels of ADAR (adenosine deaminase, RNA-specific) targets. | Pre-mRNA editing involving the conversion of adenosine to inosine is mediated by
adenosine deaminases that act on RNA (ADAR1 and ADAR2). ADARs contain multiple
double-stranded RNA(dsRNA)-binding domains in addition to an adenosine deaminase
domain. An adenosine deaminase acting on tRNAs, scTad1p (also known as scADAT1),
cloned from Saccharomyces cerevisiae has a deaminase domain related to the ADARs
but lacks dsRNA-binding domains. We have identified a gene homologous to scADAT1
in the region of Drosophila melanogaster Adh chromosome II. Recombit
Drosophila ADAT1 (dADAT1) has been expressed in the yeast Pichia pastoris and
purified. The enzyme has no activity on dsRNA substrates but is a tRNA deaminase
with specificity for adenosine 37 of insect alanine tRNA. dADAT1 shows greater
similarity to vertebrate ADARs than to yeast Tad1p, supporting the hypothesis of
a common evolutionary origin for ADARs and ADATs. dAdat1 transcripts are
maternally supplied in the egg. Zygotic expression is widespread initially and
later concentrates in the central nervous system. Genome analysis of the fruit fly Drosophila melanogaster reveals three new
ligand-gated ion channel subunits with the characteristic YXCC motif found only
in alpha-type nicotinic acetylcholine receptor subunits. The subunits are
designated Dalpha5, Dalpha6, and Dalpha7. Cloning of the Dalpha5 embryonic cDNAs
reveals an atypically large N terminus, part of which is without identifiable
sequence motifs and is specified by two polymorphic alleles. Embryonic clones
from Dalpha6 contain multiple variant transcripts arising from alternative
splicing as well as A-to-I pre-mRNA editing. Alternative splicing in Dalpha6
involves exons encoding nAChR functional domains. The Dalpha6 transcript is a
target of the Drosophila adenosine deaminase acting on RNA (dADAR). This is the
first case for any organism where a nAChR gene is the target of mRNA editing.
Seven adenosines could be modified in the extracellular ligand-binding region of
Dalpha6, four of which are also edited in the Dalpha6 ortholog in the tobacco
budworm Heliothis virescens. The conservation of an editing site between the
insect orders Diptera and Lepidoptera makes nAChR editing the most
evolutionarily conserved invertebrate RNA editing site so far described. These
findings add to our understanding of nAChR subunit diversity, which is increased
and regulated by mechanisms acting at the genomic and mRNA levels. BACKGROUND: ADARs are RNA editing enzymes that target double stranded RNA and
convert adenosine to inosine, which is read by translation machinery as if it
were guanosine. Aside from their role in generating protein diversity in the
central nervous system, ADARs have been implicated in the hypermutation of some
RNA viruses, although why this hypermutation occurs is not well understood.
RESULTS: Here we describe the hypermutation of adenosines to guanosines in the
genome of the sigma virus--a negative sense RNA virus that infects Drosophila
melanogaster. The clustering of these mutations and the context in which they
occur indicates that they have been caused by ADARs. However, ADAR-editing of
viral RNA is either rare or edited viral RNA are rapidly degraded, as we only
detected evidence for editing in two of the 104 viral isolates we studied.
CONCLUSION: This is the first evidence for ADARs targeting viruses outside of
mammals, and it raises the possibility that ADARs could play a role in the
antiviral defences of insects. RNA editing is proposed as a modulator of transcriptomes, but its biological
impact has not been fully elucidated. In particular, its importance for
transposable elements is controversial. We found RNA editing on antisense
read-through transcripts of KP elements, one of the deletion derivatives of P
transposable elements in Drosophila melanogaster. Three kinds of RNA editing
were detected at 20 sites around the terminal inverted repeats (TIR); 15 A-to-G,
four U-to-C, and one C-to-U conversions. A-to-G conversions are suggested to be
attributed to A-to-I RNA editing on KP element RNAs, because inosine (I) in RNA
is recognized as G by reverse transcriptase. TIRs were deduced to form dsRNAs as
a putative target of ADAR. This is the first report of RNA editing on mobile
elements of Drosophila. Drosophila melanogaster has a single Adar gene encoding a protein related to
mammalian ADAR2 that edits transcripts encoding glutamate receptor subunits. We
describe the structure of the Drosophila Adar locus and use ModENCODE
information to supplement published data on Adar gene transcription, and
splicing. We discuss the roles of ADAR in Drosophila in terms of the two main
types of RNA molecules edited and roles of ADARs as RNA-binding proteins.
Site-specific RNA editing events in transcripts encoding ion channel subunits
were initially found serendipitously and subsequent directed searches for
editing sites and transcriptome sequencing have now led to 972 edited sites
being identified in 597 transcripts. Four percent of D. melanogaster transcripts
are site-specifically edited and these encode a wide range of largely
membrane-associated proteins expressed particularly in CNS. Electrophysiological
studies on the effects of specific RNA editing events on ion channel subunits do
not suggest that loss of RNA editing events in ion channels consistently produce
a particular outcome such as making Adar mutant neurons more excitable. This
possibility would have been consistent with neurodegeneration seen in Adar
mutant fly brains. A further set of ADAR targets are dsRNA intermediates in
siRNA generation, derived from transposons and from structured RNA loci.
Transcripts with convergent overlapping 3' ends are also edited and the first
discovered instance of RNA editing in Drosophila, in the Rnp4F transcript, is an
example. There is no evidence yet to show that Adar antagonizes RNA interference
in Drosophila. Evidence has been obtained that catalytically inactive ADAR
proteins exert effects on microRNA generation and RNA interference. Whether all
effects of inactive ADARs are due to RNA-binding or to even further roles of
these proteins remains to be determined. RNA editing by deamination of specific adenosine bases to inosines during
pre-mRNA processing generates edited isoforms of proteins. Recoding RNA editing
is more widespread in Drosophila than in vertebrates. Editing levels rise
strongly at metamorphosis, and Adar(5G1) null mutant flies lack editing events
in hundreds of CNS transcripts; mutant flies have reduced viability, severely
defective locomotion and age-dependent neurodegeneration. On the other hand,
overexpressing an adult dADAR isoform with high enzymatic activity ubiquitously
during larval and pupal stages is lethal. Advantage was taken of this to screen
for genetic modifiers; Adar overexpression lethality is rescued by reduced
dosage of the Rdl (Resistant to dieldrin), gene encoding a subunit of inhibitory
GABA receptors. Reduced dosage of the Gad1 gene encoding the GABA synthetase
also rescues Adar overexpression lethality. Drosophila Adar(5G1) mutant
phenotypes are ameliorated by feeding GABA modulators. We demonstrate that
neuronal excitability is linked to dADAR expression levels in individual
neurons; Adar-overexpressing larval motor neurons show reduced excitability
whereas Adar(5G1) null mutant or targeted Adar knockdown motor neurons exhibit
increased excitability. GABA inhibitory signalling is impaired in human
epileptic and autistic conditions, and vertebrate ADARs may have a relevant
evolutionarily conserved control over neuronal excitability. RNA editing usually affects only a fraction of expressed transcripts and there
is a vast amount of variation in editing levels of ADAR (adenosine deaminase,
RNA-specific) targets. Here we explore natural genetic variation affecting
editing levels of particular sites in 81 natural strains of Drosophila
melanogaster. The analysis of associations between editing levels and
single-nucleotide polymorphisms allows us to map putative cis-regulatory regions
affecting editing of 16 A-to-I editing sites (cis-RNA editing quantitative trait
loci or cis-edQTLs, P < 10(-8)). The observed changes in editing levels are
validated by independent molecular technique. All identified regulatory variants
are located in close proximity of modulated editing sites. Moreover, colocalized
editing sites are often regulated by same loci. Similar to expression and
splicing QTL studies, the characterization of edQTLs will greatly expand our
understanding of cis-regulatory evolution of gene expression. |
What is the CEGA catalog? | CEGA is a catalog of conserved elements from genomic alignments. Harnessing the power of multiple species comparisons to detect genomic elements under purifying selection, CEGA provides a comprehensive set of CNCs identified at different radiations along the vertebrate lineage. Evolutionary constraint is identified using threshold-free phylogenetic modeling of unbiased and sensitive global alignments of genomic synteny blocks identified using protein orthology. The dynamic CEGA web interface displays alignments, genomic locations, as well as biologically relevant data to help prioritize and select CNCs of interest for further functional investigations. | By identifying genomic sequence regions conserved among several species,
comparative genomics offers opportunities to discover putatively functional
elements without any prior knowledge of what these functions might be.
Comparative analyses across mammals estimated 4-5% of the human genome to be
functionally constrained, a much larger fraction than the 1-2% occupied by
annotated protein-coding or RNA genes. Such functionally constrained yet
unotated regions have been referred to as conserved non-coding sequences
(CNCs) or ultra-conserved elements (UCEs), which remain largely uncharacterized
but probably form a highly heterogeneous group of elements including enhancers,
promoters, motifs, and others. To facilitate the study of such CNCs/UCEs, we
present our resource of Conserved Elements from Genomic Alignments (CEGA),
accessible from http://cega.ezlab.org. Harnessing the power of multiple species
comparisons to detect genomic elements under purifying selection, CEGA provides
a comprehensive set of CNCs identified at different radiations along the
vertebrate lineage. Evolutionary constraint is identified using threshold-free
phylogenetic modeling of unbiased and sensitive global alignments of genomic
synteny blocks identified using protein orthology. We identified CNCs
independently for five vertebrate clades, each referring to a different last
common ancestor and therefore to an overlapping but varying set of CNCs with 24
488 in vertebrates, 241 575 in amniotes, 709 743 in Eutheria, 642 701 in
Boreoeutheria and 612 364 in Euarchontoglires, spanning from 6 Mbp in
vertebrates to 119 Mbp in Euarchontoglires. The dynamic CEGA web interface
displays alignments, genomic locations, as well as biologically relevant data to
help prioritize and select CNCs of interest for further functional
investigations. |
Which protein is associated with hyperemesis gravidarum during pregrancy? | Human chorionic gonadotropin (hCG) is associated with hyperemesis gravidarum during pregrancy. | BACKGROUND: hCG is a term referring to 4 independent molecules, each produced by
separate cells and each having completely separate functions. These are hCG
produced by villous syncytiotrophoblast cells, hyperglycosylated hCG produced by
cytotrophoblast cells, free beta-subunit made by multiple primary
non-trophoblastic maligcies, and pituitary hCG made by the gonadotrope cells
of the anterior pituitary.
RESULTS AND DISCUSSION: hCG has numerous functions. hCG promotes progesterone
production by corpus luteal cells; promotes angiogenesis in uterine vasculature;
promoted the fusion of cytotrophoblast cell and differentiation to make
syncytiotrophoblast cells; causes the blockage of any immune or macrophage
action by mother on foreign invading placental cells; causes uterine growth
parallel to fetal growth; suppresses any myometrial contractions during the
course of pregcy; causes growth and differentiation of the umbilical cord;
signals the endometrium about forthcoming implantation; acts on receptor in
mother's brain causing hyperemesis gravidarum, and seemingly promotes growth of
fetal organs during pregcy. Hyperglycosylated hCG functions to promote growth
of cytotrophoblast cells and invasion by these cells, as occurs in implantation
of pregcy, and growth and invasion by choriocarcinoma cells. hCG free
beta-subunit is produced by numerous non-trophoblastic maligcies of different
primaries. The detection of free beta-subunit in these maligcies is generally
considered a sign of poor prognosis. The free beta-subunit blocks apoptosis in
cancer cells and promotes the growth and maligcy of the cancer. Pituitary hCG
is a sulfated variant of hCG produced at low levels during the menstrual cycle.
Pituitary hCG seems to mimic luteinizing hormone actions during the menstrual
cycle. Human chorionic gonadotropin (hCG) is a pregcy hormone secreted by the
placental synctiotrophoblast cell layer that has been linked to fetal growth and
various placental, uterine and fetal functions. In order to investigate the
effects of hCG on clinical endpoints, knowledge on reference range (RR)
methodology and determits of gestational hCG levels is crucial. Moreover, a
better understanding of gestational hCG physiology can improve current screening
programs and future clinical management. Serum total hCG levels were determined
in 8195 women participating in the Generation R Study. Gestational age specific
RRs using 'ultrasound derived gestational age' (US RRs) were calculated and
compared with 'last menstrual period derived gestational age' (LMP RRs) and a
model-based RR. We also investigated which pregcy characteristics were
associated with hCG levels. Compared to the US RRs, the LMP RRs were lower, most
notably for the median and lower limit levels. No considerable differences were
found between RRs calculated in the general population or in uncomplicated
pregcies only. Maternal smoking, BMI, parity, ethnicity, fetal gender,
placental weight and hyperemesis gravidarum symptoms were associated with total
hCG. We provide gestational RRs for total hCG and show that total hCG values and
RR cut-offs during pregcy vary depending on pregcy dating methodology.
This is likely due to the influence of hCG on embryonic growth, suggesting that
ultrasound based pregcy dating might be less reliable in women with high/low
hCG levels. Furthermore, we identify different pregcy characteristics that
influence total hCG levels considerably and should therefore be accounted for in
clinical studies. |
Is hydroxyurea usually used to treated infectious disease? | Hydroxyurea represents the only available disease-modifying therapy for Sickle Cell Anemia (SCA). | Clinical experience with hydroxyurea for patients with sickle cell disease (SCD)
has been accumulating for the past 25 years. The bulk of the current evidence
suggests that hydroxyurea is well-tolerated, safe, and efficacious for most
patients with SCD. Hydroxyurea has proven clinical efficacy for reducing acute
vaso-occlusive events including pain episodes and acute chest syndrome. Salutary
effects on hematological parameters include increases in fetal hemoglobin (HbF),
hemoglobin, and MCV; also significant decreases occur in WBC, ANC,
reticulocytes, LDH, and bilirubin. Treatment with hydroxyurea is usually
considered for patients with recurrent vaso-occlusive events, but additional
indications for treatment may include laboratory markers of disease severity and
evidence of chronic organ dysfunction. Ten years ago, the US Food and Drug
Administration approved hydroxyurea for adult patients with clinically severe
SCD; however, its use in children remains off-label. Despite the large body of
evidence regarding its efficacy and safety, hydroxyurea is currently prescribed
only sparingly for patients with SCD and therefore has only limited
effectiveness for this disorder; barriers to its use need to be identified and
overcome. BACKGROUND: Sickle cell anemia (SCA) is an inherited hematological disorder that
causes a large but neglected global health burden, particularly in Africa.
Hydroxyurea represents the only available disease-modifying therapy for SCA, and
has proven safety and efficacy in high-resource countries. In sub-Saharan
Africa, there is minimal use of hydroxyurea, due to lack of data, absence of
evidence-based guidelines, and inexperience among healthcare providers.
PROCEDURE: A partnership was established between investigators in North America
and sub-Saharan Africa, to develop a prospective multicenter research protocol
designed to provide data on the safety, feasibility, and benefits of hydroxyurea
for children with SCA.
RESULTS: The Realizing Effectiveness Across Continents with Hydroxyurea (REACH,
ClinicalTrials.gov NCT01966731) trial is a prospective, phase I/II open-label
dose escalation study of hydroxyurea that will treat a total of 600 children age
1-10 years with SCA: 150 at each of four different clinical sites within
sub-Saharan Africa (Angola, Democratic Republic of Congo, Kenya, and Uganda).
The primary study endpoint will be severe hematological toxicities that occur
during the fixed-dose treatment phase. REACH has an adaptive statistical design
that allows for careful assessment of toxicities to accurately identify a safe
hydroxyurea dose.
CONCLUSIONS: REACH will provide data that address critical gaps in knowledge for
the treatment of SCA in sub-Saharan Africa. By developing local expertise with
the use of hydroxyurea and helping to establish treatment guidelines, the REACH
trial results will have the potential to transform care for children with SCA in
Africa. Sickle cell disease (SCD) is the most common inherited hemoglobinopathy in the
world, with the majority of cases in sub-Saharan Africa. Concomitant nutritional
deficiencies, infections or exposure to environmental toxins exacerbate chronic
anemia in children with SCD. The resulting relative anemia is associated with
increased risk of strokes, poor cognitive function and impaired growth. It may
also attenuate optimal response to hydroxyurea therapy, the only effective and
practical treatment option for SCD in sub-Saharan Africa. This review will focus
on the epidemiology, clinical sequelae, and treatment of relative anemia in
children with SCD living in low and middle-income countries in sub-Saharan
Africa. Areas covered: The causes and treatment of relative anemia in children
with SCD in sub-Saharan Africa. The MEDLINE database was searched using medical
subject headings (MeSH) and keywords for articles regarding relative anemia in
children with SCD in sub-Saharan Africa. Expert commentary: Anemia due to
nutritional deficiencies and infectious diseases such as helminthiasis and
malaria are prevalent in sub-Saharan Africa. Their co-existence in children with
SCD increases morbidity and mortality. Therefore, preventing, diagnosing and
treating the underlying cause of this relative anemia will improve SCD-related
outcomes in children in sub-Saharan Africa. |
What is magnetoreception? | Magnetoreception is an enigmatic, poorly understood sensory ability, described mainly on the basis of behavioural studies in animals of diverse taxa. The ability to perceive geomagnetic fields (GMFs) represents a fascinating biological phenomenon. Studies on transgenic flies have provided evidence that photosensitive Cryptochromes (Cry) are involved in the response to magnetic fields (MFs). The photoreceptor protein cryptochrome is thought to host, upon light absorption, a radical pair that is sensitive to very weak magnetic fields, endowing migratory birds with a magnetic compass sense. | Author information:
(1)Institute of Entomology, Biology Centre of Academy of Sciences of the Czech
Republic, 370 05, Ceske Budejovice, Czech Republic; Department of Molecular
Biology, Faculty of Science, University of South Bohemia, 370 05, Ceske
Budejovice, Czech Republic;
(2)Department of Animal Physiology and Immunology, Faculty of Science, Masaryk
University, 611 37, Brno, Czech Republic;
(3)Department of Zoology and Animal Physiology, Institute for Biology II, RWTH
Aachen University, D-52056, Aachen, Germany;
(4)Department of Entomology, National Taiwan University, Taipei 106, Taiwan;
(5)Institute of Entomology, Biology Centre of Academy of Sciences of the Czech
Republic, 370 05, Ceske Budejovice, Czech Republic;
(6)Department of Plant Physiology and Photobiology, Faculty of Biology,
Philipps-University, D-35032 Marburg, Germany [email protected]
[email protected] [email protected].
(7)Institute of Entomology, Biology Centre of Academy of Sciences of the Czech
Republic, 370 05, Ceske Budejovice, Czech Republic; Department of Molecular
Biology, Faculty of Science, University of South Bohemia, 370 05, Ceske
Budejovice, Czech Republic; [email protected]
[email protected] [email protected].
(8)Department of Animal Physiology and Immunology, Faculty of Science, Masaryk
University, 611 37, Brno, Czech Republic; [email protected]
[email protected] [email protected]. Cryptochromes, blue-light absorbing proteins involved in the circadian clock,
have been proposed to be the receptor molecules of the avian magnetic compass.
In birds, several cryptochromes occur: Cryptochrome 2, Cryptochrome 4 and two
splice products of Cryptochrome 1, Cry1a and Cry1b. With an antibody not
distinguishing between the two splice products, Cryptochrome 1 had been detected
in the retinal ganglion cells of garden warblers during migration. A recent
study located Cry1a in the outer segments of UV/V-cones in the retina of
domestic chickens and European robins, another migratory species. Here we report
the presence of cryptochrome 1b (eCry1b) in retinal ganglion cells and displaced
ganglion cells of European Robins, Erithacus rubecula. Immuno-histochemistry at
the light microscopic and electron microscopic level showed eCry1b in the cell
plasma, free in the cytosol as well as bound to membranes. This is supported by
immuno-blotting. However, this applies only to robins in the migratory state.
After the end of the migratory phase, the amount of eCry1b was markedly reduced
and hardly detectable. In robins, the amount of eCry1b in the retinal ganglion
cells varies with season: it appears to be strongly expressed only during the
migratory period when the birds show nocturnal migratory restlessness. Since the
avian magnetic compass does not seem to be restricted to the migratory phase,
this seasonal variation makes a role of eCry1b in magnetoreception rather
unlikely. Rather, it could be involved in physiological processes controlling
migratory restlessness and thus enabling birds to perform their nocturnal
flights. Although it has been known for almost half a century that migratory birds can
detect the direction of the Earth's magnetic field, the primary sensory
mechanism behind this remarkable feat is still unclear. The leading hypothesis
centers on radical pairs-magnetically sensitive chemical intermediates formed by
photoexcitation of cryptochrome proteins in the retina. Our primary aim here is
to explain the chemical and physical aspects of the radical-pair mechanism to
biologists and the biological and chemical aspects to physicists. In doing so,
we review the current state of knowledge on magnetoreception mechanisms. We dare
to hope that this tutorial will stimulate new interdisciplinary experimental and
theoretical work that will shed much-needed additional light on this fascinating
problem in sensory biology. Magnetoreception is essential for magnetic orientation in animal migration. The
molecular basis for magnetoreception has recently been elucidated in fruitfly as
complexes between the magnetic receptor magnetoreceptor (MagR) and its ligand
cryptochrome (Cry). MagR and Cry are present in the animal kingdom. However, it
is unknown whether they perform a conserved role in diverse animals. Here we
report the identification and expression of zebrafish MagR and Cry homologs
towards understanding their roles in lower vertebrates. A single magr gene and 7
cry genes are present in the zebrafish genome. Zebrafish has four cry1 genes
(cry1aa, cry1ab, cry1ba and cry1bb) homologous to human CRY1 and a single
ortholog of human CRY2 as well as 2 cry-like genes (cry4 and cry5). By RT-PCR,
magr exhibited a high level of ubiquitous RNA expression in embryos and adult
organs, whereas cry genes displayed differential embryonic and adult expression.
Importantly, magr depletion did not produce apparent abnormalities in
organogenesis. Taken together, magr and cry2 exist as a single copy gene,
whereas cry1 exists as multiple gene duplicates in zebrafish. Our result
suggests that magr may play a dispensable role in organogenesis and predicts a
possibility to generate magr mutants for analyzing its role in zebrafish. |
Can acupuncture cause spinal epidural hematoma? | Yes, acupuncture can cause spinal epidural hematoma. | Unintentional acupuncture needling of the thoracic spinal canal produced a
spinal epidural hematoma and subarachnoid hemorrhage. This case demonstrates
that patients are sometimes reluctant to disclose folk medical treatments to
Western physicians, and the proper diagnosis may depend upon the prowess of the
neuroradiologist. STUDY DESIGN: A retrospective case report.
OBJECTIVE: The objective of this article is to report an unusual complication of
dry needling.
SUMMARY OF BACKGROUND DATA: Epidural hematomas after dry needling are quite
unusual and only a few cases of epidural hematoma after acupuncture have been
reported in the literature. We are presenting the first report of acute cervical
epidural hematoma after dry needling.
METHODS: A 58-year-old woman presented with quadriparesis and neck pain.
Magnetic resoce imaging of the spine revealed a hyperintense mass in the
T2-weighted magnetic resoce image at the C2-T2 level, which proved to be an
epidural hematoma.
RESULTS: Symptoms related to the epidural hematoma resolved after decompression.
CONCLUSION: Though rare, epidural hematomas are a possible complication when
applying needling therapies. Therapists need to have precise knowledge of human
anatomy, especially in the region where he or she will puncture. Continuous
attention must be paid throughout the whole procedure. BACKGROUND CONTEXT: Muscle needling therapy is common for chronic pain
management, but the development of unusual complications such as hemiplegia is
not well understood.
PURPOSE: We report on three cases with hemiplegia after cervical paraspinal
muscle needling and propose possible explanations for these unusual
complications.
STUDY DESIGN: Case report.
METHODS: The authors retrospectively reviewed the medical charts from a decade
(2002-2013) at Korea University Hospital. The records were systematically
searched, and the cases with hemiplegia (grade<3) after needing therapy were
collected. No conflict of interest reported. No funding received.
RESULTS: A 54-year-old woman, a 38-year-old woman, and a 60-year-old man with
hemiplegia by cervical subdural or epidural hematoma after cervical posterior
paraspinal muscle needling without direct invasion (intramuscular stimulation,
acupuncture, or intramuscular lidocaine) were observed. All patients were taken
for emergent decompressive laminectomy, and their postoperative motor function
improved substantially.
CONCLUSION: Spinal hematoma after muscle needling is unusual but was thought to
result after a rupture of the epidural or subarachnoid veins by a sharp increase
in blood pressure delivered in the intraabdominal or intrathoracic areas after
needling therapy. |
Is edema a symptom of nephrotic syndrome? | Yes, edema is the commonest presenting symptom and sign in nephrotic syndrome. | A case of interstitial shadows associated with oral cyclophosphamide therapy in
a 32-month-old girl with steroid-resistant nephrotic syndrome, who was admitted
to the Nishi-Kobe Medical Center with systemic edema, is reported. Due to the
lack of response to prednisolone, cyclophosphamide was also administered orally
at a dose of 3 mg/kg per day, 4 weeks after the start of steroid therapy.
Approximately 3 weeks after the combination treatment she developed a fever, dry
cough and cyanosis. Radiographic examination showed diffuse ground-glass shadow
in both lungs, presumably indicating that she had interstitial pneumonitis. Her
pulmonary signs and symptoms deteriorated despite various antimicrobial
treatments. A discontinuation of cyclophosphamide and the administration of
high-dose methylprednisolone yielded a dramatic improvement. These findings
suggest that the diffuse pulmonary disease in this case was induced by
cyclophosphamide. Since interstitial pneumonitis may be fatal and irreversible,
attention should be paid to this rare complication even in patients undergoing
low-dose oral cyclophosphamide treatment. A 26-year-old woman who presented facial and lower leg edema associated with
massive proteinuria was admitted to our hospital in February 1992. Nine months
before this admission, she exhibited myasthenia gravis and maligt thymoma,
and underwent total thymectomy. On admission, there was no symptom of myasthenia
gravis. She was diagnosed as having nephrotic syndrome and the first renal
biopsy was performed. The histological findings showed membranous nephropathy.
Immunofluorescent microscopy revealed that IgG and C3 were stained in a granular
pattern in the periphery, and subepithelial deposits were observed in the
basement membrane of the glomerulus by electron microscopy. With the
administration of prednisolone, proteinuria disappeared and the nephrotic
syndrome remitted. She was admitted again in January 1993 due to proteinuria and
lower leg edema following cystitis. The findings of the second renal biopsy were
unremarkable. She was administered cyclosporin A to improve the nephrotic
syndrome and to reduce the side effects of prednisolone. The proteinuria
disappeared again and this effect was dependent on the dose of cyclosporin A.
Since the first administration, no symptoms of myasthenia gravis or maligt
thymoma have been observed. The relationships among myasthenia gravis, maligt
thymoma and nephrotic syndrome were examined. Although the first renal biopsy
findings showed membranous nephropathy, from the therapeutic responses of both
prednisolone and cyclosporin A, the main course of proteinuria in this case may
have been due to minimal change nephrotic syndrome. We consider this case of
nephrotic syndrome to be important considering its etiology and the relationship
between the histological findings and its clinical course. Nephrotic syndrome represents a constellation of symptoms including
hyperalbuminuria, hypoalbuminemia, edema formation, hypercholesterolemia,
hypertension, hypercoagulopathy, and increased infection risk. The hallmark of
this syndrome is proteinuria greater than 3.5 grams per 24 hours, and the
clinical features are secondary manifestations of an underlying primary
glomerular or systemic disease. The objectives of treatment are threefold:
correcting the primary disease, decreasing the symptoms and secondary effects
associated with this syndrome, and preventing complications. This article
presents a case report of a man diagnosed with nephrotic syndrome secondary to
amyloidosis. The clinical aspects of the disease processes, the diagnostic
evaluation, the treatment course, and disease management are discussed. Oedema is the commonest presenting symptom and sign in nephrotic syndrome.
Hypercholesterolaemia, thromboembolic events, and infectious complications may
also be features. Three patients are described, each of whose nephrotic syndrome
presented with a less common symptom or sign--recurrent pleural effusion,
hypercholesterolaemia and oedema, pulmonary embolism--and, as a result,
experienced some diagnostic delay. By forgetting to consider nephrotic syndrome,
and its underlying causes, there may be inappropriate investigations and
treatment for the patient. We successfully treated a patient with chronic lymphocytic leukemia (CLL)
associated with a nephrotic syndrome. An 82-year-old man had been diagnosed as
having CLL and been under observation for a year without treatment. In January,
2001, he developed hypoprotenemia, proteinurea, and edema in the extremities and
face. With the exacerbation of the symptoms, he was admitted to our hospital in
March of the same year. Under the diagnosis of nephrotic syndrome with CLL, the
patient underwent induction therapy for CLL with fludarabine (13 mg/m2/day for 4
days), which brought about a complete remission of CLL and the disappearance of
the edema. To our knowledge, this was the first case in Japan where fludarabine
was dramatically effective in treating both CLL and the nephrotic syndrome. This
result indicated that fludarabine is beneficial for not only CLL but also
complications like nephrotic syndrome. AA amyloidosis may be a complication of Familial Mediterranean Fever (FMF). This
is a case history of a female patient who did not have the classic symptoms of
FMF, which usually precede the renal manifestation. The patient was admitted
with edema of both legs, and the nephrotic syndrome was discovered, leading to
the diagnosis of AA amyloidosis on kidney biopsy. Genetic testing uncovered the
homozygous M694V type mutation, the most common mutation of FMF, which renders
the patients prone to amyloidosis. This case represents the phenotype II of FMF,
which presents with amyloidosis without prior classic attacks of FMF. Since
effective prevention of the development of amyloidosis is available, genetic
testing should be considered in order to identify mutations which carry high
risk for the development of amyloidosis. This is also relevant in asymptomatic
individuals with family history of FMF. OBJECTIVE: To study the evidence-based therapy of edema in nephrotic syndrome by
analyzing the literatures systematically.
METHODS: The literatures related to the treatment of nephrotic edema were
retrieved from the following: Chinese Biological Medicine Database (CBM-disk),
Chinese Journals Full-text Database (CNKI, 1994-2006), Chinese Technological
Periodicals Database (VIP, 1989-2006), Chinese Evidence Biological
Medicine/Cochrane Central Database (CEBM/CCD), Cochrane Library Database,
MEDLINE (1966-2006), EMBASE (1975-2006), MEDLARS, SCI (1985-2006) and OVID by
electron and craft search with the following key words: nephrotic syndrome,
edema, recalcitrant edema, refractory edema or resistant nephrotic edema, and
treatment, diuretic therapy or human albumin treatment. The relevant literatures
on randomized controlled trials (RCT) that met the criteria were statistically
analyzed by the Coorporative network software RevMan 4.2.
RESULTS: A total of 113 articles were searched (60 in Chinese and 53 in
English), of which 12 were RCT. Three of the 12 articles were included for Meta
analysis. Meta analysis showed that dextran-40 together with furosemide was
effective for nephrotic edema. Human albumin solution could be used in nephrotic
edema patients with coexistent severe hypoalbuminemia. A combination of
diuretics by intravenous drip infusion was effective for diuretic-resistant
nephrotic edema.
CONCLUSIONS: The treatment for nephrotic edema should be individualized. The
evidence of treatment of nephrotic edema has not been fully elucidated. Further
multicentre, large sample, and randomized controlled trials are needed. Nephrotic syndrome is an unusual manifestation of IgA Nephropathy (IgAN). Some
cases respond to steroid treatment. Here we describe a case-series of IgAN
patients with steroid-responsive nephrotic syndrome. Twelve patients with IgAN
with steroid-responsive nephrotic syndrome were evaluated and followed up. All
patients presented with generalized edema. Renal insufficiency was found in two
patients. The renal biopsy of eight patients revealed wide foot process
effacement in addition to the typical features of IgAN. They showed complete
remission after steroid therapy. Seven relapses were reported in five patients;
six of the relapsed cases responded to steroid therapy. Compared with
steroid-non-responsive patients, the patients with steroid-responsive nephrotic
syndrome had shorter symptom duration, more weight gain, more proteinuria, and
lower histologic grade than did those that had steroid-non-responsive nephrotic
syndrome at presentation. None of the responders progressed to end stage renal
disease, whereas five (38%) non-responders required dialysis or renal
transplantation. Patients with IgAN who have steroid-responsive nephrotic
syndrome likely have both minimal change disease and IgAN. The clinical features
of sudden onset of generalized edema, initial heavy proteinuria and initial
severe hypoalbuminemia might help identify the subset of patients, especially in
low grade IgAN. BACKGROUND: Nephrotic syndrome is defined as urine total protein excretion
greater than 3.5 g/d or total protein-creatinine ratio greater than 3.5 g/g, low
serum albumin level, high serum cholesterol level, and peripheral edema. These
threshold levels have not been rigorously evaluated in patients with diabetic
kidney disease or by using urine albumin excretion, the preferred measure of
proteinuria in patients with diabetes.
STUDY DESIGN: Diagnostic test study.
SETTING & PARTICIPANTS: Adults with type 2 diabetes, hypertension, and urine
total protein level greater than 0.9 g/d enrolled in the Irbesartan in Diabetic
Nephropathy Trial.
INDEX TEST: Baseline measures of proteinuria (total protein and albumin
excretion and protein-creatinine and albumin-creatinine ratios). Linear
regression to relate measures.
REFERENCE TEST: Other signs and symptoms of nephrotic syndrome at baseline
(serum albumin < 3.5 g/dL, serum total cholesterol > 260 mg/dL or use of a
statin, and edema or use of a loop diuretic); progression of chronic kidney
disease during follow-up (doubling of baseline serum creatinine level or
requirement for dialysis or kidney transplantation). Logistic regression to
relate index and reference tests.
RESULTS: In 1,608 participants, total urine protein level of 3.5 g/d was
equivalent to urine albumin level of 2.2 g/d (95% confidence interval, 1.4 to
3.5). Of 1,467 participants, 641 (44%) had urine total protein level of 3.5 g/d
or greater at baseline, 132 (9%) had other signs and symptoms of nephrotic
syndrome at baseline, and 385 (26%) had progression of kidney disease during a
mean follow-up of 2.6 years. Areas under the receiver operating curves for
measures of proteinuria were 0.80 to 0.83 for other signs and symptoms of
nephrotic syndrome and 0.72 to 0.74 for kidney disease progression. Threshold
levels for nephrotic-range proteinuria and albuminuria were close to the points
of maximal accuracy for both outcomes.
LIMITATIONS: Study population limits generalizability; inability to adjust for
several variables known to affect serum albumin levels; lack of spot urine
samples.
CONCLUSIONS: The historical definition of nephrotic-range proteinuria appears
reasonable in patients with diabetic kidney disease. Equivalent thresholds for
nephrotic-range albuminuria and albumin-creatinine ratio are 2.2 g/d and 2.2
g/g, respectively. Our study aimed to obtain a comprehensive insight into the etiology of nephrotic
syndrome in our patient population. We analyzed medical records of 290 patients
with diagnosis of nephrotic syndrome as defined by International Study of Kidney
Disease in Children (ISKDC), between January 1987 and December 2000, at the
Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar. Primary
glomerular disease was found to be the most prevalent, accounting for 91.73% of
all glomerular diseases. Among primary glomerular diseases, minimal change
disease (MCD) was the most common histological lesion (43.79%). Most patients
presented within 3 months duration (61.4%) and the most common symptom was
puffiness of face (98.45%) followed by pedal edema (91%). Focal segmental
glomerulosclerosis (FSGS) was the second most common lesion (16.89%) followed by
membranous glomerulonephritis (GN) (13.4%) and membranoproliferative GN
(11.72%). Amongst secondary glomerular diseases, diabetes mellitus was the most
prevalent (4.48%), followed by lupus nephritis (3.1%). In conclusion, primary
glomerular diseases constituted the most common group encountered and the
prevalence of MCD was quite high with males, children and young adults. FSGS was
associated with a high prevalence of end-stage renal disease (ESRD; 26.53%),
hypertension (71.42%) and hematuria (81.63%). Cystinuria is an autosomal recessive disorder characterized with abnormal
tubular reabsorption of cystine and dibasic amino acids leading to cystine
urolithiasis. The classical form is caused by mutations in the SLC3A1 gene (OMIM
220100). The cornerstone of the treatment is high hydration and alkalization of
the urine to achieve urine pH between 7.0 and 7.5, at which point, cystine
solubility in the urine is optimal. These measures very often fail, and thus
addition of sulfhydryl agents like penicillamine and tiopronin
(mercaptopropionyl glycine) is recommended. Herein, we report a 3-year-old boy
with cystinuria resulting in recurrent nephrolithiasis requiring surgery and
extracorporeal shock wave lithotripsy. Nine months after introduction of
tiopronin, the boy manifested generalized edema, oliguria, and biochemical
indices of nephrotic syndrome. Tiopronin was withdrawn, and the boy was given
only supportive treatment. Within 10 days, he entered into clinical and
biochemical remission. Pediatricians should be aware of this adverse effect of
tiopronin, and therefore, testing of the urine with strips or sulfosalicylic
acid at least once weekly at home may be very helpful for early detection of
proteinuria. The present case study is on a 16-year-old woman who was suffering from
nephrotic syndrome after recovery from complete type of hydatiform mole. She was
admitted in hospital because of proteinurea and hematuria. Then she was showing
a generalized edema compatible with neprhotic syndrome. In her past medical
history she had a suction curettage for hydatiform mole. After she received 4
courses chemotherapy, she completely recovered and βhCG has fallen from 12127
IU/L to under 10 IU/mL. Then she showed generalized edema, proteinurea and
hematuria compatible with nephritic syndrome. After six courses chemotherapy the
symptoms of nephrotic syndrome and invasive mole diminished, she released from
hospital and scheduled for follow-up. Glomerular diseases are among the most common renal pathologies leading
frequently to end-stage renal disease. Clinical disease can be divided into five
different groups the features of which are determined by the underlying
pathophysiology. One of these five clinical syndromes is the nephrotic syndrome,
which is characterized by proteinuria > 3.5 g/day accompanied by hypalbuminemia,
hyperlipoproteinemia and pronounced edema. The nephrotic syndrome may be the
clinical manifestation of a row of underlying diseases. The pathophysiological
basics had remained elusive for decades, yet recently significant progress which
allows for establishing new therapeutic strategies has been made. A major
breakthrough in understanding the function of the glomerular filter unit has
been possible in the last years through both genetic and cell biological
studies, which have revealed a crucial role for the visceral epithelial cells of
the glomerulus - the podocytes. By now various factors have been found causing
podocyte damage, such as toxines, immunological phenomena or systemic disease
like diabetes mellitus. Nephrotic syndrome is basically a set of signs or symptoms that may point to
kidney problems, a condition when large amounts of protein leak out into the
urine. In children protein excretion greater than 40 mg/m2.hr(-1) indicate
presence of nephrotic syndrome. Edema is the prominent feature of nephrotic
syndrome and initially develops around the eyes and legs. The 1st line treatment
given is steroid therapy. The prospective study was conducted to determine the
rational use of steroidal therapy, steroid sensitive nephrotic syndrome and
causes of remission. 10 children were selected randomly presenting with the
complaint of steroid sensitive nephrotic syndrome. The result of this study
provide some evidence that steroidal therapy is effective in treating childhood
nephrotic syndrome and they recover more rapidly if the steroidal regimen is
carefully followed. It is concluded that rational use of steroid (prednisolone)
has a very effective role in the prevention and control of nephrotic syndrome
either at initial stage or in complicated cases. Corticosteroids have decreased
the mortality rate upto 3%. Some very interesting findings have been observed
and thus recorded and reported in this paper. BACKGROUND AND OBJECTIVES: Nephrotic syndrome (NS) represents a common disease
in pediatric nephrology typified by a relapsing and remitting course and
characterized by the presence of edema that can significantly affect the
health-related quality of life in children and adolescents. The PROMIS pediatric
measures were constructed to be publically available, efficient, precise, and
valid across a variety of diseases to assess patient reports of symptoms and
quality of life. This study was designed to evaluate the ability of children and
adolescents with NS to complete the PROMIS assessment via computer and to
initiate validity assessments of the short forms and full item banks in
pediatric NS. Successful measurement of patient reported outcomes will
contribute to our understanding of the impact of NS on children and adolescents.
DESIGN: This cross-sectional study included 151 children and adolescents 8-17
years old with NS from 16 participating institutions in North America. The
children completed the PROMIS pediatric depression, anxiety, social-peer
relationships, pain interference, fatigue, mobility and upper extremity
functioning measures using a web-based interface. Responses were compared
between patients experiencing active NS (n = 53) defined by the presence of
edema and patients with inactive NS (n = 96) defined by the absence of edema.
RESULTS: All 151 children and adolescents were successfully able to complete the
PROMIS assessment via computer. As hypothesized, the children and adolescents
with active NS were significantly different on 4 self-reported measures
(anxiety, pain interference, fatigue, and mobility). Depression, peer
relationships, and upper extremity functioning were not different between
children with active vs. inactive NS. Multivariate analysis showed that the
PROMIS instruments remained sensitive to NS disease activity after adjusting for
demographic characteristics.
CONCLUSIONS: Children and adolescents with NS were able to successfully complete
the PROMIS instrument using a web-based interface. The computer based pediatric
PROMIS measurement effectively discriminated between children and adolescents
with active and inactive NS. The domain scores found in this study are
consistent with previous reports investigating the health-related quality of
life in children and adolescents with NS. This study establishes known-group
validity and feasibility for PROMIS pediatric measures in children and
adolescents with NS. Blessed were the days when it all made sense and the apparent mechanism for
edema formation in nephrotic syndrome was straightforward: the kidneys lost
protein in the urine, which lowered the plasma oncotic pressure. Thus, fluid
leaked into the interstitium, depleting the intravascular volume with subsequent
activation of renin/aldosterone and consequent avid renal sodium retention. As
simple as that! Unfortunately, a number of clinical and laboratory observations
have raised serious concerns about the accuracy of this "underfill" hypothesis.
Instead, an "overfill" hypothesis was generated. Under this assumption, the
nephrotic syndrome not only leads to urinary protein wasting, but also to
primary sodium retention with consequent intravascular overfilling, with the
excess fluid spilling into the flood plains of the interstitium, leading to
edema. Recently, an attractive mechanism was proposed to explain this primary
sodium retention: proteinuria includes plasma proteinases, such as plasmin,
which activate the epithelial sodium channel in the collecting duct, ENaC. In
this edition, further evidence for this hypothesis is being presented by
confirming increased plasmin content in the urine of children with nephrotic
syndrome and demonstrating ENaC activation. If correct, this hypothesis would
provide a simple treatment for the edema: pharmacological blockade of ENaC, for
instance, with amiloride. Yet, how come clinicians have not empirically
discovered the presumed power of ENaC blockers in nephrotic syndrome? And why is
it that some patients clearly show evidence of intravascular underfilling? The
controversy of over- versus underfilling demonstrates how much we still have to
learn about the pathophysiology of nephrotic syndrome. Nephrotic syndrome (NS) is a renal disorder characterized by heavy proteinuria,
hypoalbuninemia, edema and hypercholesterolemia. Nephrotic syndrome in children
is known to be associated with an hypercoagulable state and thromboembolic
complications. However cerebral sinovenous thrombosis (CSVT) is very rare. Here
we report a seven-year-old child with steroid-dependent idopathic nephrotic
syndrome resulting from a minimal change disease, developed multiple cerebral
sinovenous thrombosis, presenting with headache, left sixth nerve palsy, and
papilledema. The diagnosis of CSVT was established by cranial computed
tomography, magnetic resoce imaging, and magnetic resoce angiography. He
gradually recovered after anticoagulant therapy. CSVT is very rare in nephrotic
children. The diagnosis of CSVT should be considered in any patient with
nephrotic syndrome who develops neurologic symptoms. This report highlights the
importance of suspecting and recognizing this potentially life threatening
complication and initiating early treatment. Publisher: Das Nephrotische Syndrom ist gekennzeichnet durch eine definierende
Kombination an pathologischen Laborwerten und klinischen Symptomen, d. h. einer
so genten grossen Proteinurie (häufig mehr als 3 – 3,5 g Eiweissausscheidung
im Urin pro 24 h), Hypalbuminämie, Ödemen und Hyperlipidämie. Die Ursachen des
Nephrotischen Syndroms sind vielfältig und können entweder angeboren oder
erworben, chronisch persistierend oder reversibel sein. Die Häufigkeit und
Verteilung der Ursachen des Nephrotischen Syndroms unterscheiden sich zwischen
Kindes- und Erwachsenenalter. Während im Erwachsenenalter vorrangig von
erworbenen Formen ausgegangen wird, finden sich im Kindesalter sehr häufig
genetisch determinierte Formen. Allen Erkrankungen, die mit einer nephrotischen
Proteinurie einhergehen ist gemeinsam, dass der ursächliche Defekt primär oder
sekundär die Fussfortsatzzellen (Podozyten) der Nierenglomerula betrifft. Der
vorliegende Übersichtsartikel beschäftigt sich mit der Frage, wann aus heutiger
Sicht eine genetische Abklärung beim Vorliegen eines nephrotischen Syndroms
sinnvoll ist. BACKGROUND: Nephrotic syndrome (NS) is a common clinical disease with four main
clinical manifestations: hypoalbuminemia (<30 g/L), macro-proteinuria (>3.5 g/24
h), edema, and hyperlipidemia. There is a variety of pathological types that are
associated with NS. Percutaneous renal biopsy (PRB) plays an important role in
clinical practice in that it can be used to establish a histological diagnosis,
to provide information for an ultimate NS diagnosis, and subsequent prognosis.
Our aim was to observe the psychological status of patients with NS before and
after PRB and investigate the factors affecting their psychological status.
METHODS: Two hundred and thirty-five patients with NS were enrolled in the
present study. We evaluated the psychological status of patients 24 hours before
and 6 hours after PRB by using the Symptom Check List-90 and State-Trait Anxiety
Inventory.
RESULTS: We analyzed the factors affecting the psychological status of the study
participants before and after this important NS procedure. Before the PRB
procedure was administered, the factorial anxiety and phobic anxiety scores were
higher than normal (p < 0.0.5). After PRB, only anxiety was determined to be
higher than normal in the somatization score (p < 0.05). In general, there were
higher scores among males rather than the female study participants (p < 0.05).
Scores of all indices decreased significantly in all patients after PRB (p <
0.05).
CONCLUSION: Psychological status was common in patients who underwent PRB and
were affected by many factors. |
Angelman syndrome is associated with deletion of a part of Chromosome 15 but if the deletion occurs in the paternally inherited chromosome 15, what is the disease? | Prader-Willi syndrome (PWS) results from a deletion of the paternal genes in the region of chromosome 15q11-q13. | Deletions of the proximal long arm of chromosome 15 (bands 15q11q13) are found
in the majority of patients with two distinct genetic disorders, Angelman
syndrome (AS) and Prader-Willi syndrome (PWS). The deleted regions in the two
syndromes, defined cytogenetically and by using cloned DNA probes, are similar.
However, deletions in AS occur on the maternally inherited chromosome 15, and
deletions in PWS occur on the paternally derived chromosome 15. This observation
has led to the suggestion that one or more genes in this region show
differential expression dependent on parental origin (genetic imprinting). No
genes of known function have previously been mapped to this region. We show here
that the gene encoding the GABAA (gamma-aminobutyric acid) receptor beta 3
subunit maps to the AS/PWS region. Deletion of this gene (GABRB3) was found in
AS and PWS patients with interstitial cytogenetic deletions. Evidence of beta 3
gene deletion was also found in an AS patient with an unbalanced 13;15
translocation but not in a PWS patient with an unbalanced 9;15 translocation.
The localization of this receptor gene to the AS/PWS region suggests a possible
role of the inhibitory neurotransmitter GABA in the pathogenesis of one or both
of these syndromes. Genetic imprinting has been implicated in the etiology of two clinically
distinct but cytogenetically indistinguishable disorders--Angelman syndrome (AS)
and Prader-Willi syndrome (PWS). This hypothesis is derived from two lines of
evidence. First, while the molecular extents of de novo cytogenetic deletions of
chromosome 15q11q13 in AS and PWS patients are the same, the deletions originate
from different parental chromosomes. In AS, the deletion occurs in the
maternally inherited chromosome 15, while in PWS the deletion is found in the
paternally inherited chromosome 15. The second line of evidence comes from the
deletion of an abnormal parental contribution of 15q11q13 in PWS patients
without a cytogenetic and molecular deletion. These patients have two maternal
copies and no paternal copy of 15q11q13 (maternal uniparental disomy) instead of
one copy from each parent. By qualitative hybridization with chromosome 15q11q13
specific DNA markers, we have now examined DNA samples from 10 AS patients (at
least seven of which are familial cases) with no cytogenetic or molecular
deletion of chromosome 15q11q13. Inheritance of one maternal copy and one
paternal copy of 15q11q13 was observed in each family, suggesting that paternal
uniparental disomy of 15q11q13 is not responsible for expression of the AS
phenotype in these patients. Six persons with the classical Angelman syndrome (AS) phenotype and de novo
deletions of chromosome 15q11-q13 were studied to determine the parental origin
of the chromosome deletion. Four of the 6 patients had informative cytogenetic
studies and all demonstrated maternal inheritance of the deletion. These
findings, together with other reported cases of the origin of the chromosome 15
deletion in AS, suggest that deletion of the maternally contributed chromosome
leads to the AS phenotype. This contrasts with the Prader-Willi syndrome (PWS)
in which a similar deletion of the paternally contributed chromosome 15 is
observed. In deletion cases, a parental gamete effect such as genomic imprinting
may be the best model to explain why apparently identical 15q11-q13 deletions
may develop the different phenotypes of AS or PWS. Many Prader-Willi syndrome (PWS) and Angelman syndrome (AS) patients have a
cytogenetic deletion of 15q11q13. While AS and PWS share a similar cytogenetic
anomaly, they have very different clinical phenotypes. DNAs from 4 AS patients
were examined using 5 chromosome 15q11q13-specific cloned DNA segments. With the
present level of resolution, the molecular deletions between AS and those
previously reported for PWS did not appear to differ. However, in contrast to
the paternal inheritance of the deleted chromosome 15 observed in the majority
of PWS patients, maternal inheritance of the deleted chromosome 15 was
demonstrated in the AS patients by restriction fragment length polymorphisms
(RFLPs). |
What is the phenotype of people carrying mutations in the gene PRDM12? | New therapeutic options have recently been derived from studies of individuals with congenital insensitivity to pain (CIP). Here we identified 10 different homozygous mutations in PRDM12 (encoding PRDI-BF1 and RIZ homology domain-containing protein 12) in subjects with CIP from 11 families. | PR homology domain-containing member 12 (PRDM12) belongs to a family of
conserved transcription factors implicated in cell fate decisions. Here we show
that PRDM12 is a key regulator of sensory neuronal specification in Xenopus.
Modeling of human PRDM12 mutations that cause hereditary sensory and autonomic
neuropathy (HSAN) revealed remarkable conservation of the mutated residues in
evolution. Expression of wild-type human PRDM12 in Xenopus induced the
expression of sensory neuronal markers, which was reduced using various human
PRDM12 mutants. In Drosophila, we identified Hamlet as the functional PRDM12
homolog that controls nociceptive behavior in sensory neurons. Furthermore,
expression analysis of human patient fibroblasts with PRDM12 mutations uncovered
possible downstream target genes. Knockdown of several of these target genes
including thyrotropin-releasing hormone degrading enzyme (TRHDE) in Drosophila
sensory neurons resulted in altered cellular morphology and impaired
nociception. These data show that PRDM12 and its functional fly homolog Hamlet
are evolutionary conserved master regulators of sensory neuronal specification
and play a critical role in pain perception. Our data also uncover novel
pathways in multiple species that regulate evolutionary conserved nociception. Author information:
(1)1] Department of Medical Genetics, University of Cambridge, Cambridge, UK.
[2] Cambridge Institute for Medical Research, University of Cambridge,
Cambridge, UK.
(2)Department of Orthopaedics, Medical University Vienna, Vienna, Austria.
(3)Department of Life Sciences, Graduate School of Arts and Sciences, University
of Tokyo, Tokyo, Japan.
(4)Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich,
Germany.
(5)1] Nuffield Department of Clinical Neurosciences, University of Oxford,
Oxford, UK. [2] Brain Function Research Group, School of Physiology, Faculty of
Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
(6)1] Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg,
Germany. [2] Institute of Human Genetics, Technische Universität München,
Munich, Germany.
(7)Department of Medical Genetics, University of Lausanne, Lausanne,
Switzerland.
(8)Disease Mechanism Research Core, RIKEN Brain Science Institute, Saitama,
Japan.
(9)Neusentis Research Unit, Pfizer, Cambridge, UK.
(10)1] Nuffield Department of Clinical Neurosciences, University of Oxford,
Oxford, UK. [2] School of Health and Rehabilitation Sciences, The University of
Queensland, St. Lucia, Australia.
(11)Department of Neurology, Istanbul University, Istanbul, Turkey.
(12)Ambulantes Gesundheitszentrum der Charité Campus Virchow (Humangenetik),
Universitätsmedizin Berlin, Berlin, Germany.
(13)1] Praxis für Humangenetik Cottbus, Cottbus, Germany. [2] Institut für
Humangenetik, Universitätsklinikum Leipzig, Leipzig, Germany.
(14)1] Institut für Humangenetik, Universitätsklinikum Leipzig, Leipzig,
Germany. [2] Institut für Humangenetik, Universitätsklinikum Essen, Essen,
Germany.
(15)Department of Dermatology, Our Lady's Children's Hospital, Dublin, Ireland.
(16)Department of Clinical Genetics, Odense University Hospital, Odense,
Denmark.
(17)Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.
(18)Neuropädiatrische Ambulanz, Krankenhaus der Barmherzigen Schwestern Linz,
Linz, Austria.
(19)Neurogenetics Unit, Casa Sollievo della Sofferenza, San Giovanni Rotondo,
Italy.
(20)Departamento de Cirugía Plástica, Hospital Infantil Universitario de San
José, Bogotá, Colombia.
(21)Unidad de Genética, Universidad del Rosario, Bogotá, Colombia.
(22)Institut für Neuropathologie, Uniklinik RWTH Aachen, Aachen, Germany.
(23)1] Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich,
Germany. [2] German Center for Neurodegenerative Diseases (DZNE), Munich,
Germany.
(24)Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.
(25)Department of Clinical Biochemistry, University of Cambridge, Cambridge, UK.
(26)SPZ Neuropädiatrie Charité, Universitätsmedizin Berlin, Berlin, Germany.
(27)CharitéCentrum für Zahn-, Mund- und Kieferheilkunde, Arbeitsbereich
Kinderzahnmedizin, Universitätsmedizin Berlin, Berlin, Germany.
(28)GENDIA (GENetic DIAgnostic Network), Antwerp, Belgium.
(29)Cambridge Institute for Medical Research, University of Cambridge,
Cambridge, UK.
(30)Yorkshire Regional Genetics Service, Chapel Allerton Hospital, Leeds, UK.
(31)1] Department of Neurology, University of California San Francisco, San
Francisco, California, USA. [2] Department of Neuroscience, Bambino Gesù
Children's Hospital and Research Institute, Rome, Italy.
(32)Department of Neurology and Neurophysiology, Our Lady's Children's Hospital,
Dublin, Ireland.
(33)1] Department of Neurology, Adelaide &Meath Hospital, Dublin, Ireland. [2]
Academic Unit of Neurology, Trinity College, Dublin, Ireland.
(34)1] Department of Dermatology, Our Lady's Children's Hospital, Dublin,
Ireland. [2] Clinical Medicine, Trinity College, Dublin, Ireland.
(35)Department of Clinical Genetics, Aarhus University Hospital, Aarhus,
Denmark.
(36)1] Center for Human Genetics, Bioscientia, Ingelheim, Germany. [2]
Department of Medicine, Renal Division, Freiburg University Medical Center,
Freiburg, Germany. [3] Center for Clinical Research, Freiburg University Medical
Center, Freiburg, Germany.
(37)1] Friedrich-Baur-Institute, Ludwig Maximilians University Munich, Munich,
Germany. [2] Medizinisch Genetisches Zentrum, Munich, Germany.
(38)1] Neurogenetics Group, VIB Department of Molecular Genetics, University of
Antwerp, Antwerp, Belgium. [2] Laboratory of Neurogenetics, Institute
Born-Bunge, University of Antwerp, Antwerp, Belgium. [3] Department of
Neurology, Antwerp University Hospital, Antwerp, Belgium.
(39)MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, National
Hospital for Neurology, London, UK.
(40)Department of Human Genetics, Ruhr-University Bochum, Bochum, Germany.
(41)Institute of Human Genetics, Jena University Hospital, Jena, Germany.
(42)1] Institute of Human Genetics, Technische Universität München, Munich,
Germany. [2] Department of Neuroscience, Karolinska Institutet, Stockholm,
Sweden. [3] Department of Clinical Neuroscience, Karolinska Institutet,
Stockholm, Sweden.
(43)Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford,
UK. Erroneous activation of the pain-sensing system, as in chronic or neuropathic
pain, represents a major health burden with insufficient treatment options.
However, the study of genetic disorders rendering individuals completely unable
to feel pain offers hope. All causes of congenital painlessness affect
nociceptors, evolutionarily conserved specialist neurons able to sense all type
of tissue damage. The discovery of new genes essential for sensing pain (SCN11A,
PRDM12, and CLTCL1) has provided unexpected insights into the biological
mechanisms that drive distinct stages of nociception. Drugs targeting two
previously discovered painlessness genes, NGF and SCN9A, are currently in
late-stage clinical trials; thus, characterization of these new painlessness
genes has significant potential for the generation of new classes of analgesics. |
Is there an association between Histone H3.3 mutations and glioma? | Yes, histone H3.3 mutation in the codon for lysine 27 has been found as driver mutations in pediatric glioblastoma and has been suggested to play critical roles in the pathogenesis of thalamic gliomas and diffuse intrinsic pontine gliomas. | Glioblastoma multiforme (GBM) is a lethal brain tumour in adults and children.
However, DNA copy number and gene expression signatures indicate differences
between adult and paediatric cases. To explore the genetic events underlying
this distinction, we sequenced the exomes of 48 paediatric GBM samples. Somatic
mutations in the H3.3-ATRX-DAXX chromatin remodelling pathway were identified in
44% of tumours (21/48). Recurrent mutations in H3F3A, which encodes the
replication-independent histone 3 variant H3.3, were observed in 31% of tumours,
and led to amino acid substitutions at two critical positions within the histone
tail (K27M, G34R/G34V) involved in key regulatory post-translational
modifications. Mutations in ATRX (α-thalassaemia/mental retardation syndrome
X-linked) and DAXX (death-domain associated protein), encoding two subunits of a
chromatin remodelling complex required for H3.3 incorporation at pericentric
heterochromatin and telomeres, were identified in 31% of samples overall, and in
100% of tumours harbouring a G34R or G34V H3.3 mutation. Somatic TP53 mutations
were identified in 54% of all cases, and in 86% of samples with H3F3A and/or
ATRX mutations. Screening of a large cohort of gliomas of various grades and
histologies (n = 784) showed H3F3A mutations to be specific to GBM and highly
prevalent in children and young adults. Furthermore, the presence of
H3F3A/ATRX-DAXX/TP53 mutations was strongly associated with alternative
lengthening of telomeres and specific gene expression profiles. This is, to our
knowledge, the first report to highlight recurrent mutations in a regulatory
histone in humans, and our data suggest that defects of the chromatin
architecture underlie paediatric and young adult GBM pathogenesis. Recurrent mutations affecting the histone H3.3 residues Lys27 or indirectly
Lys36 are frequent drivers of pediatric high-grade gliomas (over 30% of HGGs).
To identify additional driver mutations in HGGs, we investigated a cohort of 60
pediatric HGGs using whole-exome sequencing (WES) and compared them to 543
exomes from non-cancer control samples. We identified mutations in SETD2, a
H3K36 trimethyltransferase, in 15% of pediatric HGGs, a result that was
genome-wide significant (FDR = 0.029). Most SETD2 alterations were truncating
mutations. Sequencing the gene in this cohort and another validation cohort (123
gliomas from all ages and grades) showed SETD2 mutations to be specific to
high-grade tumors affecting 15% of pediatric HGGs (11/73) and 8% of adult HGGs
(5/65) while no SETD2 mutations were identified in low-grade diffuse gliomas
(0/45). Furthermore, SETD2 mutations were mutually exclusive with H3F3A
mutations in HGGs (P = 0.0492) while they partly overlapped with IDH1 mutations
(4/14), and SETD2-mutant tumors were found exclusively in the cerebral
hemispheres (P = 0.0055). SETD2 is the only H3K36 trimethyltransferase in
humans, and SETD2-mutant tumors showed a substantial decrease in H3K36me3 levels
(P < 0.001), indicating that the mutations are loss-of-function. These data
suggest that loss-of-function SETD2 mutations occur in older children and young
adults and are specific to HGG of the cerebral cortex, similar to the H3.3
G34R/V and IDH mutations. Taken together, our results suggest that mutations
disrupting the histone code at H3K36, including H3.3 G34R/V, IDH1 and/or SETD2
mutations, are central to the genesis of hemispheric HGGs in older children and
young adults. Recent studies have identified a Lys 27-to-methionine (K27M) mutation at one
allele of H3F3A, one of the two genes encoding histone H3 variant H3.3, in 60%
of high-grade pediatric glioma cases. The median survival of this group of
patients after diagnosis is ∼1 yr. Here we show that the levels of H3K27 di- and
trimethylation (H3K27me2 and H3K27me3) are reduced globally in H3.3K27M patient
samples due to the expression of the H3.3K27M mutant allele. Remarkably, we also
observed that H3K27me3 and Ezh2 (the catalytic subunit of H3K27
methyltransferase) at chromatin are dramatically increased locally at hundreds
of gene loci in H3.3K27M patient cells. Moreover, the gain of H3K27me3 and Ezh2
at gene promoters alters the expression of genes that are associated with
various cancer pathways. These results indicate that H3.3K27M mutation
reprograms epigenetic landscape and gene expression, which may drive
tumorigenesis. Glioblastoma (GBM) is the most aggressive primary brain tumor in human. Recent
studies on high-grade pediatric GBM have identified two recurrent mutations
(K27M and G34R/V) in genes encoding histone H3 (H3F3A for H3.3 and HIST1H3B for
H3.1). The two histone H3 mutations are mutually exclusive and give rise to
tumors in different brain compartments. Recently, we and others have shown that
the histone H3 K27M mutation specifically altered the di- and tri-methylation of
endogenous histone H3 at Lys27. Genome-wide studies using ChIP-seq on H3.3K27M
patient samples indicate a global reduction of H3K27me3 on chromatin.
Remarkably, we also found a dramatic enrichment of H3K27me3 and EZH2 (the
catalytic subunit H3K27 methyltransferase) at hundreds of gene loci in H3.3K27M
patient cells. Here, we discuss potential mechanisms whereby H3K27me3 is
enriched at chromatin loci in cells expressing the H3.3K27M mutation and report
effects of Lys-to-Met mutations of other well-studied lysine residues of histone
H3.1/H3.3 and H4 on the corresponding endogenous lysine methylation. We suggest
that mutation(s) on histones may be found in a variety of human diseases, and
the expression of mutant histones may help to address the function of histone
lysine methylation and possibly other modifications in mammalian cells. INTRODUCTION: Mutations in H3F3A, which encodes histone H3.3, commonly occur in
pediatric glioblastoma. Additionally, H3F3A K27M substitutions occur in gliomas
that arise at midline locations (eg, pons, thalamus, spine); moreover, this
substitution occurs mainly in tumors in children and adolescents. Here, we
sought to determine the association between H3F3A mutations and adult thalamic
glioma.
METHODS: Genomic H3F3A was sequenced from 20 separate thalamic gliomas.
Additionally, for 14 of the 20 gliomas, 639 genes--including cancer-related
genes and chromatin-modifier genes--were sequenced, and the Infinium
HumanMethylation450K BeadChip was used to examine DNA methylation across the
genome.
RESULTS: Of the 20 tumors, 18 were high-grade thalamic gliomas, and of these 18,
11 were from patients under 50 years of age (median age, 38 y; range, 17-46),
and 7 were from patients over 50 years of age. The H3F3A K27M mutation was
present in 10 of the 11 (91%) younger patients and absent from all 7 older
patients. Additionally, H3F3A K27M was not detected in the 2 diffuse
astrocytomas. Further sequencing revealed recurrent mutations in TP53, ATRX,
NF1, and EGFR. Gliomas with H3F3A K27M from pediatric or young adult patients
had similar, characteristic DNA methylation profiles. In contrast, thalamic
gliomas with wild-type H3F3A had DNA methylation profiles similar to those of
hemispheric glioblastomas.
CONCLUSION: We found that high-grade thalamic gliomas from young adults, like
those from children and adolescents, frequently had H3F3A K27M. Until recently, mutations in histones had not been described in any human
disease. However, genome-wide sequencing of pediatric high-grade gliomas
revealed somatic heterozygous mutations in the genes encoding histones H3.1 and
H3.3, as well as mutations in the chromatin modifiers ATRX and DAXX. The
functional significance and mechanistic details of how these mutations affect
the tumors is currently under intensive investigation. The information gained
from these studies will shed new light on normal brain development as well as
increase our understanding of the tumorigenic processes that drive pediatric
high-grade gliomas. Pediatric glioblastomas (GBM) are highly aggressive and lethal tumors. Recent
sequencing studies have shown that ~30 % of pediatric GBM and ~80 % of diffuse
intrinsic pontine gliomas show K27M mutations in the H3F3A gene, a variant
encoding histone H3.3. H3F3A K27M mutations lead to global reduction in
H3K27me3. Our goal was to develop biomarkers for the histopathologic detection
of these tumors. Therefore, we evaluated the utility of measuring H3K27me3
global reduction as a histopathologic and prognostic biomarker and tested an
antibody directed specifically against the H3.3 K27M mutation in 290 samples.
The study cohort included 203 pediatric (including 38 pediatric high-grade
astrocytomas) and 38 adult brain tumors of various subtypes and grades and 49
non-neoplastic reactive brain tissues. Detection of H3.3 K27M by
immunohistochemistry showed 100 % sensitivity and specificity and was superior
to global reduction in H3K27me3 as a biomarker in diagnosing H3F3A K27M
mutations. Moreover, cases that stained positive for H3.3 K27M showed a
significantly poor prognosis compared to corresponding negative tumors. These
results suggest that immunohistochemical detection of H3.3 K27M is a sensitive
and specific surrogate for the H3F3A K27M mutation and defines a prognostically
poor subset of pediatric GBM. Advances in understanding pediatric high-grade glioma (pHGG) genetics have
revealed key differences between pHGG and adult HGG and have uncovered unique
molecular drivers among subgroups within pHGG. The 3 core adult HGG pathways,
the receptor tyrosine kinase-Ras-phosphatidylinositide 3-kinase, p53, and
retinoblastoma networks, are also disrupted in pHGG, but they exhibit a
different spectrum of effectors targeted by mutation. There are also
similarities and differences in the genomic landscape of diffuse intrinsic
pontine glioma (DIPG) and pediatric nonbrainstem (pNBS)-HGG. In 2012, histone H3
mutations were identified in nearly 80% of DIPGs and ~35% of pNBS-HGG. These
were the first reports of histone mutations in human cancer, implicating novel
biology in pediatric gliomagenesis. Additionally, DIPG and midline pNBS-HGG vary
in the frequency and specific histone H3 amino acid substitution compared with
pNBS-HGGs arising in the cerebral hemispheres, demonstrating a molecular
difference among pHGG subgroups. The gene expression signatures as well as DNA
methylation signatures of these tumors are also distinctive, reflecting a
combination of the driving mutations and the developmental context from which
they arise. These data collectively highlight unique selective pressures within
the developing brainstem and solidify DIPG as a specific molecular and
biological entity among pHGGs. Emerging studies continue to identify novel
mutations that distinguish subgroups of pHGG. The molecular heterogeneity among
pHGGs will undoubtedly have clinical implications moving forward. The discovery
of unique oncogenic drivers is a critical first step in providing patients with
appropriate, targeted therapies. Despite these insights, our vantage point has
been largely limited to an in-depth analysis of protein coding sequences. Given
the clear importance of histone mutations in pHGG, it will be interesting to see
how aberrant epigenetic regulation contributes to tumorigenesis in the pediatric
context. New mechanistic insights may allow for the identification of distinct
vulnerabilities in this devastating spectrum of childhood tumors. Brain tumors are the most common solid tumors in children. Pediatric high-grade
glioma (HGG) accounts for ∼8-12 % of these brain tumors and is a devastating
disease as 70-90 % of patients die within 2 years of diagnosis. The failure to
advance therapy for these children over the last 30 years is largely due to
limited knowledge of the molecular basis for these tumors and a lack of disease
models. Recently, sequencing of tumor cells revealed that histone H3 is
frequently mutated in pediatric HGG, with up to 78 % of diffuse intrinsic
pontine gliomas (DIPGs) carrying K27M and 36 % of non-brainstem gliomas carrying
either K27M or G34R/V mutations. Although mutations in many chromatin modifiers
have been identified in cancer, this was the first demonstration that histone
mutations may be drivers of disease. Subsequent studies have identified
high-frequency mutation of histone H3 to K36M in chondroblastomas and to G34W/L
in giant cell tumors of bone, which are diseases of adolescents and young
adults. Interestingly, the G34 mutations, the K36M mutations, and the majority
of K27M mutations occur in genes encoding the replacement histone H3.3. Here, we
review the peculiar characteristics of histone H3.3 and use this information as
a backdrop to highlight current thinking about how the identified mutations may
contribute to disease development. Diffusely infiltrating gliomas are inherently heterogeneous tumors, and there
are ongoing efforts to establish a classification scheme that incorporates new
molecular and traditional histologic features. In less than a decade,
high-throughput sequencing of gliomas has transformed the field, uncovering
several pivotal, highly prevalent genetic alterations that stratify patients
into different prognostic and treatment-response categories. We highlight the
genetic aberrations recently discovered in isocitrate dehydrogenase, alpha
thalassemia/mental retardation syndrome X-linked, death-domain-associated
protein, histone H3.3, and telomerase reverse transcriptase and discuss how
these mutations lead to unexpected changes in the epigenetic landscape in
gliomas. We describe the opportunities these discoveries might provide for the
development of novel targeted therapy aimed at reversing early epigenetic
aberrations in glioma precursor cells. Finally, we discuss the challenges for
effective treatment of this fatal disease posed by intratumoral heterogeneity
and clonal evolution. Somatic mutations of the H3F3A and HIST1H3B genes encoding the histone H3
variants, H3.3 and H3.1, were recently identified in high-grade gliomas arising
in the thalamus, pons and spinal cord of children and young adults. However, the
complete range of patients and locations in which these tumors arise, as well as
the morphologic spectrum and associated genetic alterations remain undefined.
Here, we describe a series of 47 diffuse midline gliomas with histone H3-K27M
mutation. The 25 male and 22 female patients ranged in age from 2 to 65 years
(median = 14). Tumors were centered not only in the pons, thalamus, and spinal
cord, but also in the third ventricle, hypothalamus, pineal region and
cerebellum. Patients with pontine tumors were younger (median = 7 years) than
those with thalamic (median = 24 years) or spinal (median = 25 years) tumors. A
wide morphologic spectrum was encountered including gliomas with giant cells,
epithelioid and rhabdoid cells, primitive neuroectodermal tumor (PNET)-like
foci, neuropil-like islands, pilomyxoid features, ependymal-like areas,
sarcomatous transformation, ganglionic differentiation and pleomorphic
xanthoastrocytoma (PXA)-like areas. In this series, histone H3-K27M mutation was
mutually exclusive with IDH1 mutation and EGFR amplification, rarely co-occurred
with BRAF-V600E mutation, and was commonly associated with p53 overexpression,
ATRX loss (except in pontine gliomas), and monosomy 10. Recurrent missense mutations in histone H3 were recently reported in pediatric
gliomas and soft tissue tumors. Strikingly, these mutations only affected a
minority of the total cellular H3 proteins and occurred at or near lysine
residues at positions 27 and 36 on the amino-terminal tail of H3 that are
subject to well-characterized posttranslational modifications. Here we review
recent progress in elucidating the mechanisms by which these mutations perturb
the chromatin landscape in cells through their effects on chromatin-modifying
machinery, particularly through inhibition of specific histone lysine
methyltransferases. One common feature of histone mutations is their ability to
arrest cells in a primitive state refractory to differentiation induction,
highlighting the importance of studying these mutations in their proper
developmental context. |
Which cellular function is associated with transcription factors forkhead 1 and 2 (Fkh1 and Fkh2)? | Forkhead transcription factors establish origin timing and long-range clustering in S. cerevisiae. Here we show that the yeast Forkhead transcription factors, Fkh1 and Fkh2, are global determinants of replication origin timing. Forkhead box O (FOXO) transcription factors have a conserved function in regulating metazoan lifespan. Fkh1 and Fkh2 bind Fkh-activated origins, and interact physically with ORC, providing a plausible mechanism to cluster origins. Instead, we show that Fkh1 and Fkh2 are required for the clustering of early origins and their association with the key initiation factor Cdc45 in G1 phase, suggesting that Fkh1 and Fkh2 selectively recruit origins to emergent replication factories. | The fork-head type transcription factors are a class of regulators that function
in a broad spectrum of cellular and developmental processes in many species
ranging from yeasts to human. Previous data on yeast fork-head genes suggested
roles for these regulators in the control of cell division, sexual
differentiation and development. The genome of Schizosaccharomyces pombe has
four genes that code for proteins containing fork-head domains (FKH), two of
which have been characterised. Here we describe the remaining two genes, fhl1
and fkh2, that code for proteins containing fork-head-associated domains (FHA)
besides their FKHs. Neither of them is essential for viability, although the
deletion of either fhl1 (putative homologue of Saccharomyces cerevisiae FHL1) or
fkh2 (similar to FKH1 and FKH2 of S. cerevisiae) reduced the growth rate and
caused an extension of cell length due to delayed G2-to-M transition.
Occasionally, multiseptate cells were also produced, indicating the involvement
of fhl1 and fkh2 in efficient septum cleavage. The fkh2Delta cells were slightly
more sensitive than the wild-type cells to certain environmental stresses,
showed reduced fertility and occasional deficiencies in meiosis II, indicating
that fkh2 might also act in stress response and sexual differentiation. Forkhead box O (FOXO) transcription factors have a conserved function in
regulating metazoan lifespan. A key function in this process involves the
regulation of the cell cycle and stress responses including free radical
scavenging. We employed yeast chronological and replicative lifespan assays, as
well as oxidative stress assays, to explore the potential evolutionary
conservation of function between the FOXOs and the yeast forkhead box
transcription factors FKH1 and FKH2. We report that the deletion of both FKH
genes impedes normal lifespan and stress resistance, particularly in stationary
phase cells, which are non-responsive to caloric restriction. Conversely,
increased expression of the FKHs leads to extended lifespan and improved stress
response. Here we show the Anaphase-Promoting Complex (APC) genetically
interacts with the Fkh pathway, likely working in a linear pathway under normal
conditions, as fkh1Δ fkh2Δ post-mitotic survival is epistatic to that observed
in apc5(CA) mutants. However, under stress conditions, post-mitotic survival is
dramatically impaired in apc5(CA) fkh1Δ fkh2Δ, while increased expression of
either FKH rescues APC mutant growth defects. This study establishes the FKHs
role as evolutionarily conserved regulators of lifespan in yeast and identifies
the APC as a novel component of this mechanism under certain conditions, likely
through combined regulation of stress response, genomic stability, and cell
cycle regulation. |
What is the role of the Ctf4-interacting-peptide or CIP-box? | Crystallographic analysis classifies CIP-boxes into two related groups that target different sites on Ctf4. Mutations in the CIP-box motifs of the Dna2 nuclease or the rDNA-associated protein Tof2 do not perturb DNA synthesis genome-wide, but instead lead to a dramatic shortening of chromosome 12 that contains the large array of rDNA repeats. Data reveal unexpected complexity of Ctf4 function, as a hub that connects multiple accessory factors to the replisome. Most strikingly, Ctf4-dependent recruitment of CIP-box proteins couples other processes to DNA synthesis, including rDNA copy-number regulation. | Replisome assembly at eukaryotic replication forks connects the DNA helicase to
DNA polymerases and many other factors. The helicase binds the leading-strand
polymerase directly, but is connected to the Pol α lagging-strand polymerase by
the trimeric adaptor Ctf4. Here, we identify new Ctf4 partners in addition to
Pol α and helicase, all of which contain a "Ctf4-interacting-peptide" or
CIP-box. Crystallographic analysis classifies CIP-boxes into two related groups
that target different sites on Ctf4. Mutations in the CIP-box motifs of the Dna2
nuclease or the rDNA-associated protein Tof2 do not perturb DNA synthesis
genome-wide, but instead lead to a dramatic shortening of chromosome 12 that
contains the large array of rDNA repeats. Our data reveal unexpected complexity
of Ctf4 function, as a hub that connects multiple accessory factors to the
replisome. Most strikingly, Ctf4-dependent recruitment of CIP-box proteins
couples other processes to DNA synthesis, including rDNA copy-number regulation. |
What type of genome, (RNA or DNA, double stranded single stranded) is found in the the virus that causes blue tongue disease? | The Bluetongue virus (BTV) genome contains ten double-stranded RNA segments. | Bluetongue virus (BTV) genome contains ten double-stranded RNA segments. The
sequence of the plus strand of each of the BTV genomic double-stranded RNAs is
the same as that of its mRNA, which encodes for a single viral protein, except
the smallest S4 segment which can encode for two nonstructural proteins,
primarily for the release assistance of the viral progeny. The separation and
isolation of each BTV dsRNA segment and viral protein have provided extensive
data related to its viral infection, pathology, suppression of host cellular
functions, and eventual apoptosis of the infected host cells. This cytoplasmic
virus is also an animal killer that costs the U.S. livestock industry at least
$125 million yearly. However, this virus has no known effect on humans. Thus, it
is very safe to carry out investigation with the virus, preferably in a BSL-2
laboratory. |
What is a "chemobrain"? | The term "chemobrain" is sometimes used to denote deficits in neuropsychological functioning that may occur as a result of cancer treatment. | PURPOSE: The term "chemobrain" is sometimes used to denote deficits in
neuropsychological functioning that may occur as a result of cancer treatment.
As breast cancer survivors now commonly reach late life, it is not known whether
previous exposure to chemotherapy may affect long-term risk for cognitive
impairment. To help address this concern, this study tested whether successfully
surviving chemotherapy earlier in life was associated with later differences in
brain metabolic function as an older adult compared to controls. This question
was examined using positron emission tomography measures of brain glucose
metabolism in elderly women cancer survivors.
METHODS: Breast cancer survivors (N = 10), currently free of recurrent cancer
and without a diagnosis of a cognitive disorder, were compared to matched
healthy controls (N = 10). All subjects were imaged at rest with
[(18)F]fluorodeoxyglucose. Images were analyzed semi-quantitatively using the
Alzheimer's Discrimination Tool and a volume of interest-based approach derived
from co-registered magnetic resoce imaging.
RESULTS: Relative [(18)F]fluorodeoxyglucose uptake (normalized to global) was
significantly lower in the survivors compared with control subjects in bilateral
orbital frontal regions, consistent with differences between the groups in
cognition and executive function (i.e., Trail Making Test, Part B and
mini-mental state examination) and despite no significant differences with
respect to age, education, intelligence, or working memory. None of the
survivors and only one control manifested a global positron emission tomography
score consistent with an Alzheimer's disease metabolic pattern.
CONCLUSION: Breast cancer survivors treated with chemotherapy may manifest
long-term changes in brain glucose metabolism indicative of subtle frontal
hypometabolism, a finding consistent with results from neuropsychological
testing and other imaging modalities. Nowadays it has been established that metals and metal-induced oxidative stress
act on signal transduction pathways, and are in association with cancer growth
and spreading as well as in neurodegenerative disorders. In cases of several
neurodegenerative diseases metals, especially Al, can be considered as a risk
factor. Frequency of chemotherapy-related cognitive impairment or "chemobrain"
is mentioned to be significant in literature, although very little is known
about the chemotherapy-caused chemobrain and its connection with metal
homeostasis alteration. Dysregulation of metal homeostasis can be assumed as one
of the key factors in the progression of neurodegeneration. Therefore we were
interested in studying metal element status of 27 adult patients in 3 years
after their colectomy, 22 outpatients and 10 healthy volunteers in both genders.
Tumour markers, laboratory parameters and metal element concentrations were
determined. We found significant difference among the Al concentrations in
operated patients compared with controls. Redox active Fe and Cu levels were
also elevated slightly in this patient group. P and S concentrations changed in
different ways, and Ca levels were slightly lower, than in healthy controls.
Because of all above mentioned, examination of metal homeostasis in cancerous
patients is necessary to moderate the risk of chemobrain and other redox-related
disorders. BACKGROUND: Cognitive decline or dementia is a debilitating problem of
neurological disorders such as Alzheimer's and Parkinson's disease, including
special conditions like chemobrain. Dietary flavonoids proved to be efficacious
in delaying the incidence of neurodegenerative diseases. Two such flavonoids,
naringin (NAR) and rutin (RUT) were reported to have neuroprotective potential
with beneficial effects on spatial and emotional memories in particular.
However, the efficacy of these flavonoids is poorly understood on episodic
memory, which comprises an important form of autobiographical memory.
OBJECTIVE: This study objective is to evaluate NAR and RUT to reverse
time-delay-induced long-term and scopolamine-induced short-term episodic memory
deficits in Wistar rats.
MATERIALS AND METHODS: We have evaluated both short-term and long-term episodic
memory forms using novel object recognition task. Open field paradigm was used
to assess locomotor activity for any confounding influence on memory assessment.
Donepezil was used as positive control and was effective in both models at 1
mg/kg, i.p.
RESULTS: Animals treated with NAR and RUT at 50 and 100 mg/kg, p.o. spent
significantly more time exploring novel object compared to familiar one, whereas
control animals spent almost equal time with both objects in choice trial. NAR
and RUT dose-dependently increased recognition and discriminative indices in
time-induced long-term as well as scopolamine-induced short-term episodic memory
deficit models without interfering with the locomotor activity.
CONCLUSION: We conclude that, NAR and RUT averted both short- and long-term
episodic memory deficits in Wistar rats, which may be potential interventions
for neurodegenerative diseases as well as chemobrain condition.
SUMMARY: Incidence of Alzheimer's disease is increasing globally and the current
therapy is only symptomatic. Curative treatment is a major lacuna. NAR and RUT
are natural flavonoids proven for their pleiotropic pharmacological effects with
potential neuroprotective benefits. The study evaluated these flavonoids for
their potential to improve the most common form of episodic memory (memory of
autobiographical events in relation to time, places etc.) in two differential
animal models assessing short-term and long-term memory, respectively. We also
found that NAR and RUT were able to reverse both short-term and long-term memory
deficits dose dependently in female Wistar rats. Abbreviations used: AD:
Alzheimer's disease, AChE: Acetylcholinesterase, COX: Cyclooxygenase, DI:
Discriminative index, ITI: Inter trial interval, NAR: Naringin, RUT: Rutin,
NORT: Novel object recognition task, NOS: Nitric oxide synthase, QOL: Quality of
life, RI: Recognition index, WFI: Water for injection. PURPOSE: Most cancer patients treated with systemic adjuvant chemotherapy endure
long-lasting side effects including decrease in concentration, forgetfulness and
slower thinking, which are globally termed "chemobrain." Cotinine, the main
derivative of nicotine, improved visual and spatial working memory and decreased
depressive-like behavior in an animal model of chemotherapy-induced cognitive
impairment.
METHODS: In this study, we investigated the effect of cotinine on weight gain,
locomotor activity, cognitive abilities and depressive-like behavior in rats
treated with the chemotherapy mix, cyclophosphamide, methotrexate and
5-fluorouracil. Locomotor activity and depressive-like behavior were assessed
using the rotarod and Porsolt's tests, respectively. Changes in cognitive
abilities were determined using the novel place recognition test.
RESULTS: Female rats treated with cotinine after chemotherapy, recovered weight
faster, showed superior cognitive abilities and lower levels of depressive-like
behavior than chemotherapy, vehicle-treated rats.
CONCLUSIONS: This evidence suggests that treatment with cotinine may facilitate
the recovery and diminish the cognitive consequences of chemotherapy. |
Borden classification is used for which disease? | Borden classification systems is used for the prediction of clinical behavior of cranial dural arteriovenous fistulas. | BACKGROUND AND PURPOSE: Venous drainage patterns are a major determit of
clinical outcome in intracranial dural arteriovenous fistula (DAVF) patients. In
this study, we sought to identify MR imaging finding differences between DAVF
types classified on the basis of venous drainage patterns.
METHODS: Twenty-seven patients diagnosed as having DAVFs by conventional
angiography were included. Medical records (n = 27), and MR imaging (n = 27) and
MR angiography (MRA; n = 11) findings were retrospectively reviewed. MR imaging
findings included flow void cluster, engorged ophthalmic vein/proptosis, white
matter hyperintensity, intracranial hemorrhage, dilated leptomeningeal or
medullary vessels, venous pouch, and leptomeningeal or medullary vascular
enhancements. MRA findings included identifiable fistula, venous flow-related
enhancement, and prominent extracranial vessels. Patients' presentations and MR
imaging findings were compared among angiographic type I, II, and III cases
(according to Borden's classification), and MRA findings were compared between
cases with and without retrograde leptomeningeal venous drainage (RLVD).
RESULTS: Patient presentations were aggressive in one (13%) of the type I cases,
5 (50%) of the type II cases, and 8 (100%) of the type III cases (P = .002).
Aggressive presentations included hemorrhage, focal neurologic deficits,
seizures, intracranial hypertension, and an altered mental status. MR images
showed significantly higher frequencies of dilated leptomeningeal or medullary
vessels in a higher type [0 in type I, 5 (42%) in type II, and 7 (100%) in type
III], and of leptomeningeal or medullary vascular enhancements [0 in type I, 4
(33%) in type II, and 7 (100%) in type III]. By using MRA, fistulas were
identified only in cases with RLVD (5 [83%]). Venous flow-related enhancement
was present in 10 cases (91%). A sole false-negative case on MRA, as compared
with conventional angiography, resulted from nonvisualization of the slow venous
flow (8%). No false-positive fistula was found at the other intracranial sites
in all cases. Overall, MRA assessment for DAVF was adequate for both fistula and
venous flow-related enhancement in 10 cases (91%) and inadequate in a remaining
case because of the fistular location out of field.
CONCLUSION: MR imaging demonstration of leptomeningeal or medullary vascular
dilation and enhancements may be associated with features that are considered
predictors of a poor outcome and indicates a need for urgent therapy in
intracranial dural AVF patients. MRA is a complementary tool for the
identification of dural AVF with venous flow-related enhancement. This article presents a modification to the existing classification scales of
intracranial dural arteriovenous fistulas based on newly published research
regarding the relationship of clinical symptoms and outcome. The 2 commonly used
scales, the Borden-Shucart and Cognard scales, rely entirely on angiographic
features for categorization. The most critical anatomical feature is the
identification of cortical venous drainage (CVD; Borden-Shucart Types II and III
and Cognard Types IIb, IIa + b, III, IV, and V), as this feature identifies
lesions at high risk for future hemorrhage or ischemic neurological injury. Yet
recent data has emerged indicating that within these high-risk groups, most of
the risk for future injury is in the subgroup presenting with intracerebral
hemorrhage or nonhemorrhagic neurological deficits. The authors have defined
this subgroup as symptomatic CVD. Patients who present incidentally or with
symptoms of pulsatile tinnitus or ophthalmological phenomena have a less
aggressive clinical course. The authors have defined this subgroup as
asymptomatic CVD. Based on recent data the annual rate of intracerebral
hemorrhage is 7.4-7.6% for patients with symptomatic CVD compared with 1.4-1.5%
for those with asymptomatic CVD. The addition of asymptomatic CVD or symptomatic
CVD as modifiers to the Borden-Shucart and Cognard systems improves their
accuracy for risk stratification of patients with high-grade dural arteriovenous
fistulas. BACKGROUND: The results of treatment of intracranial dural arteriovenous
fistulas (DAVFs) since Onyx became available as an embolic agent at our
institution is reported. An algorithm is presented for treatment of DAVFs with
Onyx, and the role of endovascular transvenous, surgical, and radiosurgical
approaches are presented.
METHODS: Thirty-two patients with DAVFs treated between November 2005 and
November 2008 by endovascular embolization, surgery, or radiosurgery were
identified by a retrospective chart review. Treatment strategies were based on
the location or complexity of the fistula and the patient's clinical status.
Data collected included DAVF characteristics, obliteration rates, complications,
and outcomes. The results were analyzed and correlated with the treatment
modality.
RESULTS: Presenting symptoms were as follows: hemorrhage (n = 12 patients),
headaches (n = 12), tinnitus (n = 5), orbital symptoms (n = 7), and seizures (n
= 1). Thirty patients were treated by endovascular embolization (transarterial
only with Onyx-21, transvenous only with platinum coils-6, transarterial [Onyx]
and transvenous [coils]-3). Five patients (4 after incomplete/failed
embolization) had surgical excision of the fistula. Three patients were treated
with Gamma Knife radiosurgery (primary-1, 2 after incomplete/failed
embolization). The locations of the fistulas were transverse sigmoid (10
patients), petrotentorial (7 patients), indirect carotid cavernous fistula (7
patients), parasagittal/falcine (3 patients), middle fossa dura (3 patients),
torcula (1 patient), and anterior fossa dura (1 patient). The distribution of
patients according to Borden classification was I-6, II-13, and III-13. Complete
obliteration of the fistula was achieved in 26/32 (81%) patients after
multimodal treatment. All surgical cases had complete obliteration. In the
high-risk group with cortical venous reflux, 23/26 (89%) patients were cured.
Endovascular complications included a stuck microcatheter tip with fracture of
the tip in two patients and cranial nerves V and VII palsies in one patient. At
last follow-up (range 1-36 months), 24 patients had modified Rankin score of
0-2, 5 patients had modified Rankin score of 3-5, and 3 patients were dead. Two
patients died during admission due to the insult of the hemorrhage, and one died
after an accidental fall with subsequent traumatic subdural hematoma.
CONCLUSIONS: Multimodality treatment of DAVFs has high success rates for cure at
our center. Transarterial embolization with Onyx has become the primary
treatment for intracranial DAVFs at our center and is associated with high
safety profile and efficacy. Transvenous coil embolization is still preferred in
DAVFs with supply from arterial branches supplying cranial nerves, predomit
internal carotid artery feeders and potential extracranial-intracranial
collateral anastomosis. In our series, patients with incompletely treated DAVFs
were treated with surgery and those with partially treated type I fistulas had
radiosurgery for palliation. The clinical presentation of dural arteriovenous fistulas (DAVFs), in particular
the associated risk of intracranial hemorrhage, shows a strong correlation with
their pattern of venous drainage. The two most commonly used and clinically
accepted DAVF classifications are the Merland-Cognard classification and the
Borden classification, both based on the morphology of the venous drainage. A
revised classification that grades DAVFs through a combination of angiographic
and clinical features has also been proposed. This article offers a review of
these various classification schemes, and discusses their application to
treatment decision making. INTRODUCTION: The aetiology of dural arteriovenous fistula (DAVF) is not well
known, but it has been suggested that abnormality in angiogenesis plays a
pathological role. Abnormality in angiogenesis is also involved in diabetes
mellitus (DM). The purpose of this study was to quantify the relation between
DAVF and DM in a Korean population.
METHODS: Medical records of 192 patients with DAVF between 2002 and 2011 were
reviewed. Age, sex and the presence of DM, hypertension, hyperlipidaemia,
stroke, coronary artery disease and cancers were compared between DAVF and
control subjects. Data for control were obtained from the Korean National Health
and Nutrition Examination Survey. The relationship of DM and DAVF location,
presenting symptoms (benign vs. aggressive) and classification (Borden and
Geibprasert) were assessed using the Pearson's chi-square test.
RESULTS: Prevalence of DM was higher in DAVF patients (19.8 %) than in controls
(9.5 %; p = 0.004). Univariate analysis showed that DM (odds ratio (OR), 2.356;
95 % confidence interval (CI), 1.634-3.399; p < 0.001) and age (OR, 1.022; 95 %
CI, 1.012-1.032; p < 0.001) increased the odds of DAVF. This was supported by
multivariate analysis (DM: OR, 2.092; 95 % CI, 1.391-3.145; p = 0.0004 and Age:
OR, 1.021; 95 % CI, 1.009-1.033; p = 0.001). When these analyses were repeated
after stratification by sex, there was no relation between age and DAVF in men.
Borden II and III (p = 0.038) and aggressive symptoms (p = 0.023) were related
to DM.
CONCLUSION: There was a positive relation between DM and DAVF in a Korean
population. DAVFs with aggressive symptoms and behaviour were more commonly
related to DM. This study was to evaluate the value of four-dimensional computed tomography
angiography (4D-CTA) in the diagnosis of intracranial dural arteriovenous
fistula (DAVF). This study included 16 patients who were diagnosed to have
intracranial DAVF by digital subtraction angiography (DSA). The 4D-CTA was
performed by Aquilion ONE multi-detector CT scanner (Toshiba Medical Systems,
Japan) equipped with 320 × 0.5 mm detector rows. Standard biplane fluoroscopy
equipments (Infinix, Toshiba Medical Systems, Japan and ADVANTX LC/LP, GE
Medical Systems, Milwaukee, WI, USA) were applied in the diagnosis of
intra-arterial DSA. Examinations were performed to evaluate the findings of DSA
and 4D-CTA in each patient. The examination results were read by two independent
readers in a blind manner. All results were documented on standardized scoring
sheets. In all 16 cases, the same diagnosis results of intracranial DAVF were
obtained from DSA and 4D-CTA. The results of subtype (Borden and Cognard
classification), venous reflux and fistula sites were also accurately exhibited
in 4D-CTA. In addition, there was a little discrepancy in identifying smaller
and specific arterial branches and in distinguishing fistula type (focal or
diffuse) using 4D-CTA. Good-to-excellent agreements were made between 4D-CTA and
DSA. Therefore, 4D-CTA could be a feasible tool for the characterization of
intracranial DAVF, with respect to determining fistula site and venous drainage. OBJECT: The goal of this study was to evaluate the obliteration rate of
intracranial dural arteriovenous fistulas (DAVFs) in patients treated with
stereotactic radiosurgery (SRS), and to compare obliteration rates between
cavernous sinus (CS) and noncavernous sinus (NCS) DAVFs, and between DAVFs with
and without cortical venous drainage (CVD).
METHODS: A systematic literature review was performed using PubMed. The CS DAVFs
and the NCS DAVFs were categorized using the Barrow and Borden classification
systems, respectively. The DAVFs were also categorized by location and by the
presence of CVD. Statistical analyses of pooled data were conducted to assess
complete obliteration rates in CS and NCS DAVFs, and in DAVFs with and without
CVD.
RESULTS: Nineteen studies were included, comprising 729 patients harboring 743
DAVFs treated with SRS. The mean obliteration rate was 63% (95% CI 52.4%-73.6%).
Complete obliteration for CS and NCS DAVFs was achieved in 73% and 58% of
patients, respectively. No significant difference in obliteration rates between
CS and NCS DAVFs was found (OR 1.72, 95% CI 0.66-4.46; p=0.27). Complete
obliteration in DAVFs with and without CVD was observed in 56% and 75% of
patients, respectively. A significantly higher obliteration rate was observed in
DAVFs without CVD compared with DAVFs with CVD (OR 2.37, 95% CI 1.07-5.28;
p=0.03).
CONCLUSIONS: Treatment with SRS offers favorable rates of DAVF obliteration with
low complication rates. Patients harboring DAVFs that are refractory or not
amenable to endovascular or surgical therapy may be safely and effectively
treated using SRS. The commonly used Borden and Cognard classification systems for the prediction
of clinical behavior of cranial dural arteriovenous shunts focus on the venous
drainage, particularly the presence of leptomeningeal venous drainage, and on
the direction of flow, particularly the presence of retrograde flow. In
addition, the latter includes ectasia and spinal drainage as criteria of two
distinct grades. However, none of the above classifications (a) differentiates
direct from exclusive leptomeningeal venous drainage, (b) considers cortical
venous congestion as a factor potentially associated with an aggressive clinical
course, and (c) anticipates ectasia in shunts with a mixed dural-cortical venous
drainage (type 2). In this study, we analyzed the angiographic images of 107
consecutive patients having a cranial dural arteriovenous fistula with
leptomeningeal venous drainage, based on a newly developed scheme. This scheme,
symbolized with the acronym "DES," groups the dural shunts according to three
factors: directness and exclusivity of leptomeningeal venous drainage and signs
of venous strain. According to the combination of the three factors, eight
different groups were distinguished. All analyzed cases could be assigned to one
of these groups. Directness of leptomeningeal venous drainage expresses the
exact site of the shunt (bridging vein vs sinus wall), whereas exclusivity
expresses venous outlet restrictions. All bridging vein shunts had a direct
leptomeningeal venous drainage. Almost all bridging vein shunts and all
"isolated" sinus shunts had an exclusive leptomeningeal venous drainage. Venous
strain, manifested as ectasia and/or congestion, denotes the decompensation of
the cerebral venous system due to the shunt reflux. The comparison of the
presented concept with the currently used classifications highlighted the
advantages of the former and the weaknesses of the latter. The efficacy and limitations of transarterial acrylic glue embolization for the
treatment of intracranial dural arteriovenous fistulas (DAVFs) were
investigated. Thirty-four DAVFs treated by transarterial embolization using
n-butyl cyanoacrylate were retrospectively reviewed. The locations of DAVFs were
the transverse-sigmoid sinus in 11, tentorium in 10, cranial vault in 9, and
superior sagittal sinus, jugular bulb, foramen magnum, and middle cranial fossa
in 1 each. Borden classification was type I in 7, type II in 3, and type III in
24. Eight patients had undergone prior transvenous coil embolization. Complete
obliteration rate was 56% immediately after embolization, 71% at follow-up
angiography, and 85% after additional treatments (1 transvenous embolization and
4 direct surgery). Complications occurred in three patients, consisting of
asymptomatic vessel perforations during cannulation in two patients and leakage
of contrast medium resulting in medullary infarction in one patient.
Transarterial glue embolization is highly effective for Borden type III DAVF
with direct cortical venous drainage, but has limitations for Borden type I and
II DAVFs in which the affected sinus is part of the normal venous circulation.
Onyx is a new liquid embolic material and is becoming the treatment of choice
for DAVF. The benefits of glue embolization compared to Onyx embolization are
high thrombogenicity, and relatively low risks of cranial nerve palsies and of
excessive migration into the draining veins of high flow fistula. Transarterial
glue embolization continues to be useful for selected patients, and complete
cure can be expected in most patients with fewer complications if combined with
transvenous embolization or direct surgery. PURPOSE: To investigate which clinical and angioarchitectural features were
associated with the occurrence of intracranial hemorrhage in patients with
intracranial dural arteriovenous fistulas (DAVFs).
MATERIALS AND METHODS: We retrospectively reviewed the clinical and
angioarchitectural features of 236 consecutive patients diagnosed with DAVF in
our department from April 2009 to November 2013. Two groups of patients, with or
without intracranial hemorrhage as clinical presentation at the initial
diagnosis, were analysed to identify the differences in clinical and
angioarchitectural features in univariate analysis. A multivariate logistic
regression model was also developed to assess the independent contribution of
the potential risk factors. Associations were considered significant for p<0.05.
RESULTS: Fifty-six patients (23.7%) presented with intracranial hemorrhage at
the initial diagnosis of DAVF. In univariate analysis, male patients (p =
0.002), patients with medical history of smoking (p<0.001) or alcohol
consumption (p = 0.022), and DAVFs located at the tentorium (p = 0.010),
frontalbasal (p = 0.007), foramen magnum (p = 0.043) or cerebral convexity
(p<0.001) were associated with an increased risk of intracranial hemorrhage. A
higher risk of hemorrhagic occurrence was also observed in DAVFs with
superficial cortical venous drainage (p<0.001), deep venous drainage (p =
0.003), occluded venous sinus (p<0.032), or higher Borden type (p<0.001). A
multivariate logistic regression model showed that intracranial hemorrhage in
patients with DAVFs was correlated with higher Borden classification (OR 5.880;
95% CI, 3.370-10.257; p<0.001).
CONCLUSION: Venous drainage pattern was the only independent risk factor of
intracranial hemorrhage in our patients with intracranial DAVF. The other
potential risk factors may be confounding factors in predicting intracranial
hemorrhage. PURPOSE: The purpose of this article is to prospectively test the hypothesis
that time-resolved CT angiography (TRCTA) on a Toshiba 320-slice CT scanner
enables the same characterization of cerebral vascular malformation (CVM)
including arteriovenous malformation (AVM), dural arteriovenous fistula (DAVF),
pial arteriovenous fistula (PAVF) and developmental venous anomaly (DVA)
compared to digital subtraction angiography (DSA).
MATERIALS AND METHODS: Eighteen (eight males, 10 females) consecutive patients
(11 AVM, four DAVF, one PAVF, and two DVA) underwent 19 TRCTA (Aquillion one,
Toshiba) for suspected CVM diagnosed on routine CT or MRI. One patient with a
dural AVF underwent TRCTA and DSA twice before and after treatment. Of the 18
patients, 13 were followed with DSA (Artis, Siemens) within two months of TRCTA.
Twenty-three sequential volume acquisitions of the whole head were acquired
after injection of 50 ml contrast at the rate of 4 ml/sec. Two patients with DVA
did not undergo DSA. Two TRCTA were not assessed because of technical
problems.TRCTAs were independently reviewed by two neuroradiologists and DSA by
two other neuroradiologists and graded according to the Spetzler-Martin
classification, Borden classification, overall diagnostic quality, and level of
confidence. Weighted kappa coefficients (k) were calculated to compare reader's
assessment of DSA vs TRCTA.
RESULTS: There was excellent (k = 0.83 and 1) to good (k = 0.56, 0.61, 0.65 and
0.67) agreement between the different possible pairs of neuroradiologists for
the assessment of vascular malformations.
CONCLUSION: TRCTA may be a sufficient noninvasive substitute for conventional
DSA in certain clinical situations. |
Which effects create neighborhoods of transcriptional regulation in eukaryotes? | Enhancer Sharing Promotes Neighborhoods of Transcriptional Regulation Across Eukaryotes. Here, we present cross-organismic evidence suggesting that most EP pairs are compatible, largely determined by physical proximity rather than specific interactions. we find that the transcription of gene neighbors is correlated over distances that scale with genome size. We propose that enhancer sharing is commonplace among eukaryotes, and that EP distance is an important layer of information in gene regulation. | MOTIVATION: Identifying the target genes regulated by transcription factors
(TFs) is the most basic step in understanding gene regulation. Recent advances
in high-throughput sequencing technology, together with chromatin
immunoprecipitation (ChIP), enable mapping TF binding sites genome wide, but it
is not possible to infer function from binding alone. This is especially true in
mammalian systems, where regulation often occurs through long-range enhancers in
gene-rich neighborhoods, rather than proximal promoters, preventing
straightforward assignment of a binding site to a target gene.
RESULTS: We present EMBER (Expectation Maximization of Binding and Expression
pRofiles), a method that integrates high-throughput binding data (e.g. ChIP-chip
or ChIP-seq) with gene expression data (e.g. DNA microarray) via an unsupervised
machine learning algorithm for inferring the gene targets of sets of TF binding
sites. Genes selected are those that match overrepresented expression patterns,
which can be used to provide information about multiple TF regulatory modes. We
apply the method to genome-wide human breast cancer data and demonstrate that
EMBER confirms a role for the TFs estrogen receptor alpha, retinoic acid
receptors alpha and gamma in breast cancer development, whereas the conventional
approach of assigning regulatory targets based on proximity does not.
Additionally, we compare several predicted target genes from EMBER to
interactions inferred previously, examine combinatorial effects of TFs on gene
regulation and illustrate the ability of EMBER to discover multiple modes of
regulation.
AVAILABILITY: All code used for this work is available at
http://dinner-group.uchicago.edu/downloads.html. Enhancers physically interact with transcriptional promoters, looping over
distances that can span multiple regulatory elements. Given that
enhancer-promoter (EP) interactions generally occur via common protein
complexes, it is unclear whether EP pairing is predomitly deterministic or
proximity guided. Here, we present cross-organismic evidence suggesting that
most EP pairs are compatible, largely determined by physical proximity rather
than specific interactions. By reanalyzing transcriptome datasets, we find that
the transcription of gene neighbors is correlated over distances that scale with
genome size. We experimentally show that nonspecific EP interactions can explain
such correlation, and that EP distance acts as a scaling factor for the
transcriptional influence of an enhancer. We propose that enhancer sharing is
commonplace among eukaryotes, and that EP distance is an important layer of
information in gene regulation. |
Is Pfh1 a component of the replisome? | No. Pfh1 Is an Accessory Replicative Helicase that Interacts with the Replisome to Facilitate Fork Progression and Preserve Genome Integrity. DNA replication through hard-to-replicate sites, including both highly transcribed RNA Pol II and Pol III genes, requires the S. pombe Pfh1 helicase. | Replication forks encounter impediments as they move through the genome,
including natural barriers due to stable protein complexes and highly
transcribed genes. Unlike lesions generated by exogenous damage, natural
barriers are encountered in every S phase. Like humans, Schizosaccharomyces
pombe encodes a single Pif1 family DNA helicase, Pfh1. Here, we show that Pfh1
is required for efficient fork movement in the ribosomal DNA, the mating type
locus, tRNA, 5S ribosomal RNA genes, and genes that are highly transcribed by
RNA polymerase II. In addition, converged replication forks accumulated at all
of these sites in the absence of Pfh1. The effects of Pfh1 on DNA replication
are likely direct, as it had high binding to sites whose replication was
impaired in its absence. Replication in the absence of Pfh1 resulted in DNA
damage specifically at those sites that bound high levels of Pfh1 in wild-type
cells and whose replication was slowed in its absence. Cells depleted of Pfh1
were inviable if they also lacked the human TIMELESS homolog Swi1, a replisome
component that stabilizes stalled forks. Thus, Pfh1 promotes DNA replication and
separation of converged replication forks and suppresses DNA damage at
hard-to-replicate sites. Replicative DNA helicases expose the two strands of the double helix to the
replication apparatus, but accessory helicases are often needed to help forks
move past naturally occurring hard-to-replicate sites, such as tightly bound
proteins, RNA/DNA hybrids, and DNA secondary structures. Although the
Schizosaccharomyces pombe 5'-to-3' DNA helicase Pfh1 is known to promote fork
progression, its genomic targets, dynamics, and mechanisms of action are largely
unknown. Here we address these questions by integrating genome-wide
identification of Pfh1 binding sites, comprehensive analysis of the effects of
Pfh1 depletion on replication and DNA damage, and proteomic analysis of Pfh1
interaction partners by immunoaffinity purification mass spectrometry. Of the
621 high confidence Pfh1-binding sites in wild type cells, about 40% were sites
of fork slowing (as marked by high DNA polymerase occupancy) and/or DNA damage
(as marked by high levels of phosphorylated H2A). The replication and integrity
of tRNA and 5S rRNA genes, highly transcribed RNA polymerase II genes, and
nucleosome depleted regions were particularly Pfh1-dependent. The association of
Pfh1 with genomic integrity at highly transcribed genes was S phase dependent,
and thus unlikely to be an artifact of high transcription rates. Although Pfh1
affected replication and suppressed DNA damage at discrete sites throughout the
genome, Pfh1 and the replicative DNA polymerase bound to similar extents to both
Pfh1-dependent and independent sites, suggesting that Pfh1 is proximal to the
replication machinery during S phase. Consistent with this interpretation, Pfh1
co-purified with many key replisome components, including the hexameric MCM
helicase, replicative DNA polymerases, RPA, and the processivity clamp PCNA in
an S phase dependent manner. Thus, we conclude that Pfh1 is an accessory DNA
helicase that interacts with the replisome and promotes replication and
suppresses DNA damage at hard-to-replicate sites. These data provide insight
into mechanisms by which this evolutionarily conserved helicase helps preserve
genome integrity. |
What is the function of mTOR? | The mTOR protein regulates assembly of the translation initiation machinery and are master regulators of cellular survival, growth and metabolism. | The mammalian target of rapamycin (mTOR), a downstream effector of the
phosphatidylinositol 3-kinase (PI3K)/Akt (protein kinase B) signaling pathway
that mediates cell survival and proliferation, is a prime strategic target for
anticancer therapeutic development. By targeting mTOR, the immunosuppressant and
antiproliferative agent rapamycin inhibits signals required for cell cycle
progression, cell growth, and proliferation. Both rapamycin and novel rapamycin
analogues with more favorable pharmaceutical properties, such as CCI-779, RAD
001, and AP23573, are highly specific inhibitors of mTOR. In essence, these
agents gain function by binding to the immunophilin FK506 binding protein 12 and
the resultant complex inhibits the activity of mTOR. Because mTOR activates both
the 40S ribosomal protein S6 kinase (p70s6k) and the eukaryotic initiation
factor 4E-binding protein-1, rapamycin-like compounds block the actions of these
downstream signaling elements, which results in cell cycle arrest in the G1
phase. Rapamycin and its analogues also prevent cyclin-dependent kinase (CDK)
activation, inhibit retinoblastoma protein phosphorylation, and accelerate the
turnover of cyclin D1, leading to a deficiency of active CDK4/cyclin D1
complexes, all of which potentially contribute to the prominent inhibitory
effects of rapamycin at the G1/S boundary of the cell cycle. Rapamycin and
rapamycin analogues have demonstrated impressive growth-inhibitory effects
against a broad range of human cancers, including breast cancer, in preclinical
and early clinical evaluations. In breast cancer cells, PI3K/Akt and mTOR
pathways seem to be critical for the proliferative responses mediated by the
epidermal growth factor receptor, the insulin growth factor receptor, and the
estrogen receptor. Furthermore, these pathways may be constitutively activated
in cancers with many types of aberrations, including those with loss of PTEN
suppressor gene function. Therefore, the development of inhibitors of mTOR and
related pathways is a rational therapeutic strategy for breast and other
maligcies that possess a wide range of aberrant molecular constituents. This
review will summarize the principal mechanisms of action of rapamycin and
rapamycin derivatives, as well as the potential utility of these agents as
anticancer therapeutic agents with an emphasis on breast cancer. The preliminary
results of early clinical evaluations with rapamycin analogues and the unique
developmental challenges that lie ahead will also be discussed. The mammalian target of rapamycin (mTOR), a member of the phosphoinositide
3-kinase related kinase (PIKK) family, plays a central role in the regulation of
cell growth. The cellular function of mTOR has been proposed based solely on
loss-of-function analyses using the specific inhibitor rapamycin or
RNAi-mediated knockdown. There have been recent reports of mTOR mutants with
enhanced activity that were isolated by genetic screening in yeast. These
isolated mTOR mutants exhibited enhanced kinase activity in vitro, and when
expressed in cells, prevented the dephosphorylation of known mTOR substrates.
The application of these mutants in gain-of-function analyses has enabled a
re-evaluation of the function of mTOR. Although these studies confirmed many of
the proposed mTOR functions some unexpected observations urged a reconsideration
of the regulatory mechanisms and the physiological function of the mTOR pathway.
Hyperactive mTOR mutants are thus valuable tools for analysis of the activation
mechanism as well as the in vivo function of mTOR. Cancer cells feature increased de novo lipogenesis. Sterol regulatory
element-binding protein 1 (SREBP1), when presented in its mature form (mSREBP1),
enhances lipogenesis by increasing transcription of several of its target genes.
Mammalian target of rapamycin (mTOR) complexes, mTORC1 and mTORC2, are master
regulators of cellular survival, growth and metabolism. A role for mTORC1 in the
regulation of SREBP1 activity has been suggested; however, the connection
between mTORC2 and SREBP1 has not been clearly established and hence is the
focus of this study. mTOR kinase inhibitors (for example, INK128), which inhibit
both mTORC1 and mTORC2, decreased mSREBP1 levels in various cancer cell lines.
Knockdown of rictor, but not raptor, also decreased mSREBP1. Consistently,
reduced mSREBP1 levels were detected in cells deficient in rictor or Sin1
compared with parent or rictor-deficient cells with re-expression of ectopic
rictor. Hence it is mTORC2 inhibition that causes mSREBP1 reduction. As a
result, expression of the mSREBP1 target genes acetyl-CoA carboxylase and
fatty-acid synthase was suppressed, along with suppressed lipogenesis in cells
exposed to INK128. Moreover, mSREBP1 stability was reduced in cells treated with
INK128 or rictor knockdown. Inhibition of proteasome, GSK3 or the E3 ubiquitin
ligase, FBXW7, prevented mSREBP1 reduction induced by mTORC2 inhibition. Thus
mTORC2 inhibition clearly facilitates GSK3-dependent, FBXW7-mediated mSREBP1
degradation, leading to mSREBP1 reduction. Accordingly, we conclude that mTORC2
positively regulates mSREBP1 stability and lipogenesis. Our findings reveal a
novel biological function of mTORC2 in the regulation of lipogenesis and warrant
further study in this direction. Protein synthesis regulation via mammalian target of rapamycin complex 1
(mTORC1) signaling pathway has key roles in neural development and function, and
its dysregulation is involved in neurodevelopmental disorders associated with
autism and intellectual disability. mTOR regulates assembly of the translation
initiation machinery by interacting with the eukaryotic initiation factor eIF3
complex and by controlling phosphorylation of key translational regulators.
Collybistin (CB), a neuron-specific Rho-GEF responsible for X-linked
intellectual disability with epilepsy, also interacts with eIF3, and its binding
partner gephyrin associates with mTOR. Therefore, we hypothesized that CB also
binds mTOR and affects mTORC1 signaling activity in neuronal cells. Here, by
using induced pluripotent stem cell-derived neural progenitor cells from a male
patient with a deletion of entire CB gene and from control individuals, as well
as a heterologous expression system, we describe that CB physically interacts
with mTOR and inhibits mTORC1 signaling pathway and protein synthesis. These
findings suggest that disinhibited mTORC1 signaling may also contribute to the
pathological process in patients with loss-of-function variants in CB. |
What is the indication for valbenazine? | Valbenazine granted breakthrough drug status for treating tardive dyskinesia. | Abnormal involuntary movements often improve in response to anti-dopaminergic
drugs. In contrast to classic neuroleptics that block dopamine receptors, drugs
that deplete presynaptic dopamine by blocking vesicular monoamine transporter
type 2 (VMAT2) seem to be safer and have little or no risk of tardive
dyskinesia. This is one reason why there has been a recent emergence of novel
VMAT2 inhibitors. Areas covered: Since the approval of tetrabenazine, the
classic VMAT2 inhibitor, in the treatment of chorea associated with Huntington
disease (HD), other VMAT2 inhibitors (e.g. deutetrabenazine and valbenazine)
have been studied in the treatment of HD-related chorea, tardive dyskinesia and
tics associated with Tourette syndrome. This review, based largely on a detailed
search of PubMed, will summarize the pharmacology and clinical experience with
the various VMAT2 inhibitors. Expert commentary: Because of differences in
pharmacology and pharmacokinetics these new VMAT2 inhibitors promise to be at
least as effective as tetrabenazine but with a lower risk of adverse effects,
such as sedation, insomnia, depression, parkinsonism, and akathisia. |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.