922 research outputs found

    Loss of Num1-mediated cortical dynein anchoring negatively impacts respiratory growth

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    Num1 is a multifunctional protein that both tethers mitochondria to the plasma membrane and anchors dynein to the cell cortex during nuclear inheritance. Previous work has examined the impact loss of Num1-based mitochondrial tethering has on dynein function in Saccharomyces cerevisiae; here, we elucidate its impact on mitochondrial function. We find that like mitochondria, Num1 is regulated by changes in metabolic state, with the protein levels and cortical distribution of Num1 differing between fermentative and respiratory growth conditions. In cells lacking Num1, we observe a reproducible respiratory growth defect, suggesting a role for Num1 in not only maintaining mitochondrial morphology, but also function. A structure–function approach revealed that, unexpectedly, Num1- mediated cortical dynein anchoring is important for normal growth under respiratory conditions. The severe respiratory growth defect in Δnum1 cells is not specifically due to the canonical functions of dynein in nuclear migration but is dependent on the presence of dynein, as deletion of DYN1 in Δnum1 cells partially rescues respiratory growth. We hypothesize that misregulated dynein present in cells that lack Num1 negatively impacts mitochondrial function resulting in defects in respiratory growth

    MyD88-dependent interplay between myeloid and endothelial cells in the initiation and progression of obesity-associated inflammatory diseases.

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    Low-grade systemic inflammation is often associated with metabolic syndrome, which plays a critical role in the development of the obesity-associated inflammatory diseases, including insulin resistance and atherosclerosis. Here, we investigate how Toll-like receptor-MyD88 signaling in myeloid and endothelial cells coordinately participates in the initiation and progression of high fat diet-induced systemic inflammation and metabolic inflammatory diseases. MyD88 deficiency in myeloid cells inhibits macrophage recruitment to adipose tissue and their switch to an M1-like phenotype. This is accompanied by substantially reduced diet-induced systemic inflammation, insulin resistance, and atherosclerosis. MyD88 deficiency in endothelial cells results in a moderate reduction in diet-induced adipose macrophage infiltration and M1 polarization, selective insulin sensitivity in adipose tissue, and amelioration of spontaneous atherosclerosis. Both in vivo and ex vivo studies suggest that MyD88-dependent GM-CSF production from the endothelial cells might play a critical role in the initiation of obesity-associated inflammation and development of atherosclerosis by priming the monocytes in the adipose and arterial tissues to differentiate into M1-like inflammatory macrophages. Collectively, these results implicate a critical MyD88-dependent interplay between myeloid and endothelial cells in the initiation and progression of obesity-associated inflammatory diseases

    Estimating the incidence of acute infectious intestinal disease in the community in the UK:A retrospective telephone survey

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    Objectives: To estimate the burden of intestinal infectious disease (IID) in the UK and determine whether disease burden estimations using a retrospective study design differ from those using a prospective study design. Design/Setting: A retrospective telephone survey undertaken in each of the four countries comprising the United Kingdom. Participants were randomly asked about illness either in the past 7 or 28 days. Participants: 14,813 individuals for all of whom we had a legible recording of their agreement to participate Outcomes: Self-reported IID, defined as loose stools or clinically significant vomiting lasting less than two weeks, in the absence of a known non-infectious cause. Results: The rate of self-reported IID varied substantially depending on whether asked for illness in the previous 7 or 28 days. After standardising for age and sex, and adjusting for the number of interviews completed each month and the relative size of each UK country, the estimated rate of IID in the 7-day recall group was 1,530 cases per 1,000 person-years (95% CI: 1135 – 2113), while in the 28-day recall group it was 533 cases per 1,000 person-years (95% CI: 377 – 778). There was no significant variation in rates between the four countries. Rates in this study were also higher than in a related prospective study undertaken at the same time. Conclusions: The estimated burden of disease from IID varied dramatically depending on study design. Retrospective studies of IID give higher estimates of disease burden than prospective studies. Of retrospective studies longer recall periods give lower estimated rates than studies with short recall periods. Caution needs to be exercised when comparing studies of self-reported IID as small changes in study design or case definition can markedly affect estimated rates

    Effect of PSI-697, a novel P-selectin inhibitor, on platelet-monocyte aggregate formation in humans

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    Background: Platelet activation is central to the pathogenesis of acute coronary syndromes. Surface expression of P‐selectin on activated platelets induces formation of platelet–monocyte aggregates and promotes vascular inflammation and thrombosis. P‐selectin antagonism may represent a novel therapeutic strategy in vascular disease. We aimed to investigate the effects of the novel P‐selectin antagonist PSI‐697 on platelet–monocyte aggregate formation in humans. Methods and Results: In a double‐blind, randomized, placebo‐controlled crossover study, healthy smokers were randomized to receive either oral PSI‐697 600 mg or matched placebo. The sequence of treatment was also randomized, with all subjects receiving both PSI‐697 and placebo. Platelet–monocyte aggregates were measured by flow cytometry at 4 and 24 hours in the presence and absence of thrombin receptor‐activating peptide (TRAP; 0.1 to 1.0 μm/L). The ex vivo addition of TRAP caused a concentration‐dependent increase in platelet–monocyte aggregates from 8.2% to 94.8% (P<0.001). At 4 and 24 hours, plasma concentrations of PSI‐697 increased to 1906 and 83 ng/mL, respectively (P<0.001). PSI‐697 had no demonstrable effect on either stimulated or unstimulated platelet–monocyte aggregates at 4 or 24 hours (P>0.05). P‐selectin‐blocking antibody (CLB‐Thromb6), but not PSI‐697, inhibited both stimulated and unstimulated platelet–monocyte aggregate formation in vitro (P<0.001). Conclusions: The novel small‐molecule P‐selectin antagonist PSI‐697 did not inhibit basal or stimulated platelet–monocyte aggregate formation in humans at the dose tested. Its clinical efficacy remains to be established

    Individualized angiotensin-converting enzyme (ACE)-inhibitor therapy in stable coronary artery disease based on clinical and pharmacogenetic determinants: The PERindopril GENEtic (PERGENE) risk model

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    Background-Patients with stable coronary artery disease (CAD) constitute a heterogeneous group in which the treatment benefits by angiotensin-converting enzyme (ACE)-inhibitor therapy vary between individuals. Our objective was to integrate clinical and pharmacogenetic determinants in an ultimate combined risk prediction model. Methods and Results-Clinical, genetic, and outcomes data were used from 8726 stable CAD patients participating in the EUROPA/PERGENE trial of perindopril versus placebo. Multivariable analysis of phenotype data resulted in a clinical risk score (range, 0-21 points). Three single-nucleotide polymorphisms (rs275651 and rs5182 in the angiotensin-II type I-receptor gene and rs12050217 in the bradykinin type I-receptor gene) were used to construct a pharmacogenetic risk score (PGXscore; range, 0-6 points). Seven hundred eighty-five patients (9.0%) experienced the primary endpoint of cardiovascular mortality, nonfatal myocardial infarction or resuscitated cardiac arrest, during 4.2 years of follow-up. Absolute risk reductions ranged from 1.2% to 7.5% in the 73.5% of patients with PGXscore of 0 t

    Studies on the actin-binding protein HS1 in platelets

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    <p>Abstract</p> <p>Background</p> <p>The platelet cytoskeleton mediates the dramatic change in platelet morphology that takes place upon activation and stabilizes thrombus formation. The Arp2/3 complex plays a vital role in these processes, providing the protrusive force for lamellipodia formation. The Arp2/3 complex is highly regulated by a number of actin-binding proteins including the haematopoietic-specific protein HS1 and its homologue cortactin. The present study investigates the role of HS1 in platelets using HS1<sup>-/- </sup>mice.</p> <p>Results</p> <p>The present results demonstrate that HS1 is not required for platelet activation, shape change or aggregation. Platelets from HS1<sup>-/- </sup>mice spread normally on a variety of adhesion proteins and have normal F-actin and Arp2/3 complex distributions. Clot retraction, an actin-dependent process, is also normal in these mice. Platelet aggregation and secretion is indistinguishable between knock out and littermates and there is no increase in bleeding using the tail bleeding assay.</p> <p>Conclusion</p> <p>This study concludes that HS1 does not play a major role in platelet function. It is possible that a role for HS1 is masked by the presence of cortactin.</p

    Volume 01

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    Introduction from Dean Dr. Charles Ross Three Decades of Digging: Undergraduate Archeology at Longwood by Jessica Fields and Stephanie Neeley Interactions of Allelopathy and Heat Stress in Plants by Derek W. Hambright and Mary E. Lehman Inertial Electrostatic Confinement D-D Fusion Device: Construction and Simulation by Andrew R. Grzankowski Shackled Nim by Zachary Johnson Development of GC-MS and Chemometric Methods for the Analysis of Accelerants in Arson Cases by Boone M. Prentice A Comparison of Image Analysis Methods in cDNA Microarrays by Ashley M. Swandby Perceived Sexual Activity of Short and Long-Term Relationships by Victoria Morgan and Katie Williamson Elderly Male Communication by Kristine G. Bender Three Poems: “Adam and Eve and an Orange Tree”, “The Name of Everything Before Dying”, and “The ‘Poet Voice’” by Katelyn N. Romaine There\u27s Nothing Like Dancing, After All : Marriage and Gender in the Dance Scenes of Jane Austen\u27s Novels by D. Nicole Swann Two Poems: “Age Nine with Mother” and “The Apple That Crawls Away From the Tree” by Jessica Fox Untitled by Mike McAteer Room 9 by Alex Grabiec Two Photographs: “Gracie” and “Emily” by Laura Nodtvedt Bowling Lanes Night by Nick Costa Two Paintings: “Can and Kettle” and “Scarecrow” by Rachel Wolfe Exploring Henrik Ibsen\u27s “Perr Gynt” by Zack Dalton Creative Writing Scholarship at Longwood University Music Scholarship at Longwood – Senior Recital Arianne K. Burrus Longwood University Theater – Peer Gyn

    Multi-site genetic analysis of diffusion images and voxelwise heritability analysis : a pilot project of the ENIGMA–DTI working group

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    The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium was set up to analyze brain measures and genotypes from multiple sites across the world to improve the power to detect genetic variants that influence the brain. Diffusion tensor imaging (DTI) yields quantitative measures sensitive to brain development and degeneration, and some common genetic variants may be associated with white matter integrity or connectivity. DTI measures, such as the fractional anisotropy (FA) of water diffusion, may be useful for identifying genetic variants that influence brain microstructure. However, genome-wide association studies (GWAS) require large populations to obtain sufficient power to detect and replicate significant effects, motivating a multi-site consortium effort. As part of an ENIGMA–DTI working group, we analyzed high-resolution FA images from multiple imaging sites across North America, Australia, and Europe, to address the challenge of harmonizing imaging data collected at multiple sites. Four hundred images of healthy adults aged 18–85 from four sites were used to create a template and corresponding skeletonized FA image as a common reference space. Using twin and pedigree samples of different ethnicities, we used our common template to evaluate the heritability of tract-derived FA measures. We show that our template is reliable for integrating multiple datasets by combining results through meta-analysis and unifying the data through exploratory mega-analyses. Our results may help prioritize regions of the FA map that are consistently influenced by additive genetic factors for future genetic discovery studies. Protocols and templates are publicly available at (http://enigma.loni.ucla.edu/ongoing/dti-working-group/)
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