139 research outputs found
Genetically Confirmed Spinal Muscular Atrophy Type 3 With Epilepsy In A Malay Patient, A Case Report
Spinal Muscular Atrophy (SMA) is an autosomal recessive disease affecting the anterior horn cells of the spinal cord. The diagnosis is usually based on the clinical presentation with or without muscle biopsy and the molecular detection of mutation in the SMNI gene. There have been a few reported cases of SMA with central nervous system involvement, but these were without genetic diagnoses. We report a Malay girl with genetically confirmed SMA complicated by epilepsy. She first presented with motor weakness at the age of 17 months and recurrent seizures a month later. The molecular genetic
analysis of her SMN gene showed homozygous deletion of exon 7 and 8 of the SMN1 gene. The seizure responded well to carbamazepine. To the best of our knowledge, this is the first case of genetically comfirmed Malay SMA patient with an association with epilepsy
Two-dimensional universal conductance fluctuations and the electron-phonon interaction of topological surface states in Bi2Te2Se nanoribbons
The universal conductance fluctuations (UCFs), one of the most important
manifestations of mesoscopic electronic interference, have not yet been
demonstrated for the two-dimensional surface state of topological insulators
(TIs). Even if one delicately suppresses the bulk conductance by improving the
quality of TI crystals, the fluctuation of the bulk conductance still keeps
competitive and difficult to be separated from the desired UCFs of surface
carriers. Here we report on the experimental evidence of the UCFs of the
two-dimensional surface state in the bulk insulating Bi2Te2Se nanoribbons. The
solely-B\perp-dependent UCF is achieved and its temperature dependence is
investigated. The surface transport is further revealed by weak
antilocalizations. Such survived UCFs of the topological surface states result
from the limited dephasing length of the bulk carriers in ternary crystals. The
electron-phonon interaction is addressed as a secondary source of the surface
state dephasing based on the temperature-dependent scaling behavior
Correlation between p38 mitogen-activated protein kinase and human telomerase reverse transcriptase in sarcomas
<p>Abstract</p> <p>Background</p> <p>One of the major components of telomerase is the human telomerase reverse transcriptase (hTERT) as the catalytic protein. hTERT mRNA expression are reported to be associated with prognosis and tumor progression in several sarcomas. However, there is no clear understanding of the mechanisms of hTERT in human sarcomas. Recent studies have suggested that signals transmitted through p38 mitogen-activated protein kinase (MAPK) can increase or decrease hTERT transcription in human cells. The purpose of this study was to analyse the correlation between p38 MAPK and hTERT in sarcoma samples.</p> <p>Methods</p> <p>We investigated 36 soft tissue malignant fibrous histiocytomas (MFH), 24 liposarcomas (LS) and 9 bone MFH samples for hTERT and p38 MAPK expression. Quantitative detection of hTERT and p38 MAPK was performed by RT-PCR.</p> <p>Results</p> <p>There was a significant positive correlation between the values of hTERT and p38 MAPK in all samples (r = 0.445, p = 0.0001), soft tissue MFH (r = 0.352, p = 0.0352), LS (r = 0.704, p = 0.0001) and bone MFH samples (r = 0.802, p = 0.0093). Patients who had a higher than average expression of p38 MAPK had a significantly worse prognosis than other patients (p = 0.0036).</p> <p>Conclusions</p> <p>p38 MAPK may play a role in up-regulation of hTERT, and therefore, p38 MAPK may be a useful marker in the assessment of hTERT and patients' prognosis in sarcomas.</p
Adipocyte-specific protein tyrosine phosphatase 1B deletion increases lipogenesis, adipocyte cell size and is a minor regulator of glucose homeostasis
Peer reviewedPublisher PD
Cardiac fibrosis can be attenuated by blocking the activity of transglutaminase 2 using a selective small-molecule inhibitor
Cardiac fibrosis is implicit in all forms of heart disease but there are no effective treatments. In this report, we investigate the role of the multi-functional enzyme Transglutaminase 2 (TG2) in cardiac fibrosis and assess its potential as a therapeutic target. Here we describe the use a highly selective TG2 small-molecule inhibitor to test the efficacy of TG2 inhibition as an anti-fibrotic therapy for heart failure employing two different in vivo models of cardiac fibrosis: Progressively induced interstitial cardiac fibrosis by pressure overload using angiotensin II infusion: Acutely induced focal cardiac fibrosis through myocardial infarction by ligation of the left anterior descending coronary artery (AMI model). In the AMI model, in vivo MRI showed that the TG2 inhibitor 1–155 significantly reduced infarct size by over 50% and reduced post-infarct remodelling at 20 days post insult. In both models, Sirius red staining for collagen deposition and levels of the TG2-mediated protein crosslink ε(γ-glutamyl)lysine were significantly reduced. No cardiac rupture or obvious signs of toxicity were observed. To provide a molecular mechanism for TG2 involvement in cardiac fibrosis, we show that both TGFβ1-induced transition of cardiofibroblasts into myofibroblast-like cells and TGFβ1- induced EndMT, together with matrix deposition, can be attenuated by the TG2 selective inhibitor 1–155, suggesting a new role for TG2 in regulating TGFβ1 signalling in addition to its role in latent TGFβ1 activation. In conclusion, TG2 has a role in cardiac fibrosis through activation of myofibroblasts and matrix deposition. TG2 inhibition using a selective small-molecule inhibitor can attenuate cardiac fibrosis
Zigzag Turning Preference of Freely Crawling Cells
The coordinated motion of a cell is fundamental to many important biological
processes such as development, wound healing, and phagocytosis. For eukaryotic
cells, such as amoebae or animal cells, the cell motility is based on crawling
and involves a complex set of internal biochemical events. A recent study
reported very interesting crawling behavior of single cell amoeba: in the
absence of an external cue, free amoebae move randomly with a noisy, yet,
discernible sequence of ‘run-and-turns’ analogous to the
‘run-and-tumbles’ of swimming bacteria. Interestingly, amoeboid
trajectories favor zigzag turns. In other words, the cells bias their crawling
by making a turn in the opposite direction to a previous turn. This property
enhances the long range directional persistence of the moving trajectories. This
study proposes that such a zigzag crawling behavior can be a general property of
any crawling cells by demonstrating that 1) microglia, which are the immune
cells of the brain, and 2) a simple rule-based model cell, which incorporates
the actual biochemistry and mechanics behind cell crawling, both exhibit similar
type of crawling behavior. Almost all legged animals walk by alternating their
feet. Similarly, all crawling cells appear to move forward by alternating the
direction of their movement, even though the regularity and degree of zigzag
preference vary from one type to the other
Physics of Neutron Star Crusts
The physics of neutron star crusts is vast, involving many different research
fields, from nuclear and condensed matter physics to general relativity. This
review summarizes the progress, which has been achieved over the last few
years, in modeling neutron star crusts, both at the microscopic and macroscopic
levels. The confrontation of these theoretical models with observations is also
briefly discussed.Comment: 182 pages, published version available at
<http://www.livingreviews.org/lrr-2008-10
Polymorphisms in MTHFR, MS and CBS Genes and Homocysteine Levels in a Pakistani Population
Background: Hyperhomocysteinemia (\u3e15 mol/L) is highly prevalent in South Asian populations including Pakistan. In order to investigate the genetic determinants of this condition, we studied 6 polymorphisms in genes of 3 enzymes--methylenetetrahydrofolate reductase (MTHFR, C677T, A1298C), methionine synthase (MS, A2756G), cystathionine-beta-synthase (CBS, T833C/844ins68, G919A) involved in homocysteine metabolism and investigated their interactions with nutritional and environmental factors in a Pakistani population. Methodology/Principal Findings: In a cross-sectional survey, 872 healthy adults (355 males and 517 females, age 18-60 years) were recruited from a low-income urban population in Karachi. Fasting venous blood was obtained and assessed for plasma/serum homocysteine, folate, vitamin B12, pyridoxal phosphate and blood lead. DNA was isolated and genotyping was performed by PCR-RFLP (restriction-fragment-length-polymorphism) based assays. The average changes in homocysteine levels for MTHFR 677CT and TT genotypes were positive [beta(SE beta), 2.01(0.63) and 16.19(1.8) mol/L, respectively]. Contrary to MTHFR C677T polymorphism, the average changes in plasma homocysteine levels for MS 2756AG and GG variants were negative [beta(SE beta), -0.56(0.58) and -0.83(0.99) mol/L, respectively]. The average change occurring for CBS 844ins68 heterozygous genotype (ancestral/insertion) was -1.88(0.81) mol/L. The combined effect of MTHFR C677T, MS A2756G and CBS 844ins68 genotypes for plasma homocysteine levels was additive (p valu
Antibody Vh Repertoire Differences between Resolving and Chronically Evolving Hepatitis C Virus Infections
Despite the production of neutralizing antibodies to hepatitis C virus (HCV), many patients fail to clear the virus and instead develop chronic infection and long-term complications. To understand how HCV infection perturbs the antibody repertoire and to identify molecular features of antibody genes associated with either viral clearance or chronic infection, we sequenced the V(D)J region of naïve and memory B cells of 6 persons who spontaneously resolved an HCV infection (SR), 9 patients with a newly diagnosed chronically evolving infection (CE), and 7 healthy donors. In both naïve and memory B cells, the frequency of use of particular antibody gene subfamilies and segments varied among the three clinical groups, especially between SR and CE. Compared to CE, SR antibody genes used fewer VH, D and JH gene segments in naïve B cells and fewer VH segments in memory B cells. SR and CE groups significantly differed in the frequency of use of 7 gene segments in naïve B cell clones and 3 gene segments in memory clones. The nucleotide mutation rates were similar among groups, but the pattern of replacement and silent mutations in memory B cell clones indicated greater antigen selection in SR than CE. Greater clonal evolution of SR than CE memory B cells was revealed by analysis of phylogenetic trees and CDR3 lengths. Pauciclonality of the peripheral memory B cell population is a distinguishing feature of persons who spontaneously resolved an HCV infection. This finding, previously considered characteristic only of patients with HCV-associated lymphoproliferative disorders, suggests that the B cell clones potentially involved in clearance of the virus may also be those susceptible to abnormal expansion
Culture dependent and independent analyses of 16S rRNA and ATP citrate lyase genes : a comparison of microbial communities from different black smoker chimneys on the Mid-Atlantic Ridge
Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Extremophiles 12 (2008): 627-640, doi:10.1007/s00792-008-0167-5.The bacterial and archaeal communities of three deep-sea hydrothermal vent systems
located on the Mid-Atlantic Ridge (MAR; Rainbow, Logatchev and Broken Spur) were
investigated using an integrated culture-dependent and independent approach.
Comparative molecular phylogenetic analyses, using the 16S rRNA gene and the deduced
amino acid sequences of the alpha and beta subunits of the ATP citrate lyase encoding
genes were carried out on natural microbial communities, on an enrichment culture
obtained from the Broken Spur chimney, and on novel chemolithoautotrophic bacteria
and reference strains originally isolated from several different deep-sea vents. Our data
showed that the three MAR hydrothermal vent chimneys investigated in this study host
very different microbial assemblages. The microbial community of the Rainbow chimney
was dominated by thermophilic, autotrophic, hydrogen-oxidizing, sulfur- and nitrate
reducing Epsilonproteobacteria related to the genus Caminibacter. The detection of
sequences related to sulfur-reducing bacteria and archaea (Archaeoglobus) indicated that
thermophilic sulfate reduction might also be occurring at this site. The Logatchev
bacterial community included several sequences related to mesophilic sulfur-oxidizing
bacteria, while the archaeal component of this chimney was dominated by sequences
related to the ANME-2 lineage, suggesting that anaerobic oxidation of methane may be
occurring at this site. Comparative analyses of the ATP citrate lyase encoding genes from
natural microbial communities suggested that Epsilonproteobacteria were the dominant
primary producers using the reverse TCA cycle (rTCA) at Rainbow, while Aquificales of
the genera Desulfurobacterium and Persephonella were prevalent in the Broken Spur
chimney.This research was supported by NSF grants MCB 04-56676 (C.V.), OCE 03-27353 (C.V.), MCB 04-56689 (S.M.S.), a grant from the New Jersey Agricultural Experiment Station to C.V., and a NIH Ph.D. Training
Program in Biotechnology Fellowship (NIH NIGMS 5 T32 GM08339) to J.V. M.H. was
supported through a postdoctoral scholarship from the Woods Hole Oceanographic
Institution
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