7,571 research outputs found

    Protein kinase A (PKA) phosphorylation of Shp2 inhibits its phosphatase activity and modulates ligand specificity.

    Get PDF
    Pathological cardiac hypertrophy (an increase in cardiac mass resulting from stress-induced cardiac myocyte growth) is a major factor underlying heart failure. Src homology 2 domain-containing phosphatase (Shp2) is critical for cardiac function as mutations resulting in loss of Shp2 catalytic activity are associated with congenital cardiac defects and hypertrophy. We have identified a novel mechanism of Shp2 inhibition that may promote cardiac hypertrophy. We demonstrate that Shp2 is a component of the A-kinase anchoring protein (AKAP)-Lbc complex. AKAP-Lbc facilitates protein kinase A (PKA) phosphorylation of Shp2, which inhibits Shp2 phosphatase activity. We have identified two key amino acids in Shp2 that are phosphorylated by PKA: Thr73 contributes a helix-cap to helix αB within the N-terminal SH2 domain of Shp2, whereas Ser189 occupies an equivalent position within the C-terminal SH2 domain. Utilizing double mutant PKA phospho-deficient (T73A/S189A) and phospho-mimetic (T73D/S189D) constructs, in vitro binding assays, and phosphatase activity assays, we demonstrate that phosphorylation of these residues disrupts Shp2 interaction with tyrosine-phosphorylated ligands and inhibits its protein tyrosine phosphatase activity. Overall, our data indicate that AKAP-Lbc integrates PKA and Shp2 signaling in the heart and that AKAP-Lbc-associated Shp2 activity is reduced in hypertrophic hearts in response to chronic β-adrenergic stimulation and PKA activation. Thus, while induction of cardiac hypertrophy is a multifaceted process, inhibition of Shp2 activity through AKAP-Lbc-anchored PKA is a previously unrecognized mechanism that may promote this compensatory response

    Dramatic Increases in Obesity and Overweight Prevalence and Body Mass Index Among Ethnic-Immigrant and Social Class Groups in the United States, 1976–2008

    Get PDF
    This study examined trends in US obesity and overweight prevalence and body mass index (BMI) among 30 immigrant groups, stratified by race/ethnicity and length of immigration, and among detailed education, occupation, and income/poverty groups from 1976 to 2008. Using 1976–2008 National Health Interview Surveys, differentials in obesity, overweight, and BMI, based on self-reported height and weight, were analyzed by using disparity indices, logistic, and linear regression. The obesity prevalence for the US population aged ≥18 tripled from 8.7% in 1976 to 27.4% in 2008. Overweight prevalence increased from 36.9% in 1976 to 62.0% in 2008. During 1991–2008, obesity prevalence for US-born adults increased from 13.9 to 28.7%, while prevalence for immigrants increased from 9.5 to 20.7%. While immigrants in each ethnic group and time period had lower obesity and overweight prevalence and BMI than the US-born, immigrants’ risk of obesity and overweight increased with increasing duration of residence. In 2003–2008, obesity prevalence ranged from 2.3% for recent Chinese immigrants to 31–39% for American Indians, US-born blacks, Mexicans, and Puerto Ricans, and long-term Mexican and Puerto Rican immigrants. Between 1976 and 2008, the obesity prevalence more than quadrupled for those with a college education or sales occupation. Although higher prevalence was observed for lower education, income, and occupation levels in each period, socioeconomic gradients in obesity and overweight decreased over time because of more rapid increases in prevalence among higher socioeconomic groups. Continued immigrant and socioeconomic disparities in prevalence will likely have substantial impacts on future obesity trends in the US

    Association of the 894G>T polymorphism in the endothelial nitric oxide synthase gene with risk of acute myocardial infarction

    Get PDF
    Background: This study was designed to investigate the association of the 894G>T polymorphism in the eNOS gene with risk of acute myocardial infarction (AMI), extent of coronary artery disease (CAD) on coronary angiography, and in-hospital mortality after AMI. Methods: We studied 1602 consecutive patients who were enrolled in the GEMIG study. The control group was comprised by 727 individuals, who were randomly selected from the general adult population. Results: The prevalence of the Asp298 variant of eNOS was not found to be significantly and independently associated with risk of AMI (RR = 1.08, 95%CI = 0.77–1.51, P = 0.663), extent of CAD on angiography (OR = 1.18, 95%CI = 0.63–2.23, P = 0.605) and in-hospital mortality (RR = 1.08, 95%CI = 0.29–4.04, P = 0.908). Conclusion: In contrast to previous reports, homozygosity for the Asp298 variant of the 894G>T polymorphism in the eNOS gene was not found to be associated with risk of AMI, extent of CAD and in-hospital mortality after AM

    Monolithic simulation of convection-coupled phase-change - verification and reproducibility

    Full text link
    Phase interfaces in melting and solidification processes are strongly affected by the presence of convection in the liquid. One way of modeling their transient evolution is to couple an incompressible flow model to an energy balance in enthalpy formulation. Two strong nonlinearities arise, which account for the viscosity variation between phases and the latent heat of fusion at the phase interface. The resulting coupled system of PDE's can be solved by a single-domain semi-phase-field, variable viscosity, finite element method with monolithic system coupling and global Newton linearization. A robust computational model for realistic phase-change regimes furthermore requires a flexible implementation based on sophisticated mesh adaptivity. In this article, we present first steps towards implementing such a computational model into a simulation tool which we call Phaseflow. Phaseflow utilizes the finite element software FEniCS, which includes a dual-weighted residual method for goal-oriented adaptive mesh refinement. Phaseflow is an open-source, dimension-independent implementation that, upon an appropriate parameter choice, reduces to classical benchmark situations including the lid-driven cavity and the Stefan problem. We present and discuss numerical results for these, an octadecane PCM convection-coupled melting benchmark, and a preliminary 3D convection-coupled melting example, demonstrating the flexible implementation. Though being preliminary, the latter is, to our knowledge, the first published 3D result for this method. In our work, we especially emphasize reproducibility and provide an easy-to-use portable software container using Docker.Comment: 20 pages, 8 figure

    Differential expression analysis for sequence count data

    Get PDF
    *Motivation:* High-throughput nucleotide sequencing provides quantitative readouts in assays for RNA expression (RNA-Seq), protein-DNA binding (ChIP-Seq) or cell counting (barcode sequencing). Statistical inference of differential signal in such data requires estimation of their variability throughout the dynamic range. When the number of replicates is small, error modelling is needed to achieve statistical power.

*Results:* We propose an error model that uses the negative binomial distribution, with variance and mean linked by local regression, to model the null distribution of the count data. The method controls type-I error and provides good detection power. 

*Availability:* A free open-source R software package, _DESeq_, is available from the Bioconductor project and from "http://www-huber.embl.de/users/anders/DESeq":http://www-huber.embl.de/users/anders/DESeq

    Components of acquisition-to-acquisition variance in continuous arterial spin labelling (CASL) imaging

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Images of perfusion estimates obtained with the continuous arterial spin labelling technique are characterized by variation between single acquisitions. Little is known about the spatial determinants of this variation during the acquisition process and their impact on voxel-by-voxel estimates of effects.</p> <p>Results</p> <p>We show here that the spatial patterns of covariance between voxels arising during the acquisition of these images uncover distinct mechanisms through which this variance arises: through variation in global perfusion levels; through the action of large vessels and other, less well characterized, large anatomical structures; and through the effect of noisy areas such as the edges of the brain.</p> <p>Conclusions</p> <p>Knowledge of these covariance patterns is important to experimenters for a correct interpretation of findings, especially for studies where relatively few acquisitions are made.</p

    A new Al-Zr-Ti master alloy for ultrasonic grain refinement of wrought and foundry aluminum alloys

    Get PDF
    A new grain refiner master alloy based on the Al-Zr-Ti system was prepared by salt assisted synthesis. 90% of Al3Zr particles in the master alloy were ranged between 1 and 13 μm. 80% reduction of grain size was observed with the addition of 0.2wt% Zr equivalent master alloy combined with ultrasonic treatment in an Al alloy. The new master alloy demonstrated 30% improvement in grain refinement efficiency compared to the one prepared by a conventional alloy route.The authors wish to acknowledge financial support from the ExoMet Project, which is co-funded by the European Commission in the 7th Framework Programme (contract FP7-NMP3-LA-2012-280421), by the European Space Agency and by the individual partner organisations

    Transcriptomic Analyses of Inner Ear Sensory Epithelia in Zebrafish

    Get PDF
    Analysis of gene expression has the potential to assist in the understanding of multiple cellular processes including proliferation, cell-fate specification, senesence, and activity in both healthy and disease states. Zebrafish model has been increasingly used to understand the process of hearing and the development of the vertebrate auditory system. Within the zebrafish inner ear, there are three otolith organs, each containing a sensory macula of hair cells. The saccular macula is primarily involved in hearing, the utricular macula is primarily involved in balance and the function of the lagenar macula is not completely understood. The goal of this study is to understand the transcriptional differences in the sensory macula associated with different otolith organs with the intention of understanding the genetic mechanisms responsible for the distinct role each organ plays in sensory perception. The sensory maculae of the saccule, utricle, and lagena were dissected out of adult Et(krt4:GFP) zebrafish expressing green fluorescent protein in hair cells for transcriptional analysis. The total RNAs of the maculae were isolated and analyzed by RNA GeneChip microarray. Several of the differentially expressed genes are known to be involved in deafness, otolith development and balance. Gene expression among these otolith organs was very well conserved with less than 10% of genes showing differential expression. Data from this study will help to elucidate which genes are involved in hearing and balance. Furthermore, the findings of this study will assist in the development of the zebrafish model for human hearing and balance disorders. Anat Rec, 303:527-543, 2020. © 2019 American Association for Anatomy
    corecore