150 research outputs found

    Access and Outcomes Among Minority Transplant Patients, 1999–2008, with a Focus on Determinants of Kidney Graft Survival

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    Coincident with an increasing national interest in equitable health care, a number of studies have described disparities in access to solid organ transplantation for minority patients. In contrast, relatively little is known about differences in posttransplant outcomes between patients of specific racial and ethnic populations. In this paper, we review trends in access to solid organ transplantation and posttransplant outcomes by organ type, race and ethnicity. In addition, we present an analysis of categories of factors that contribute to the racial/ethnic variation seen in kidney transplant outcomes. Disparities in minority access to transplantation among wait-listed candidates are improving, but persist for those awaiting kidney, simultaneous kidney and pancreas and intestine transplantation. In general, graft and patient survival among recipients of solid organ transplants is highest for Asians and Hispanic/Latinos, intermediate for whites and lowest for African Americans. Although much of the difference in outcomes between racial/ethnic groups can be accounted for by adjusting for patient characteristics, important observed differences remain. Age and duration of pretransplant dialysis exposure emerge as the most important determinants of survival in an investigation of the relative impact of center-related versus patient-related variables on kidney graft outcomes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79270/1/j.1600-6143.2009.03009.x.pd

    Impaired mitochondrial fat oxidation induces adaptive remodeling of muscle metabolism

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    © 2015, National Academy of Sciences. All rights reserved. The correlations between intramyocellular lipid (IMCL), decreased fatty acid oxidation (FAO), and insulin resistance have led to the hypothesis that impaired FAO causes accumulation of lipotoxic intermediates that inhibit muscle insulin signaling. Using a skeletal muscle-specific carnitine palmitoyltransferase-1 KO model, we show that prolonged and severe mitochondrial FAO inhibition results in increased carbohydrate utilization, along with reduced physical activity; increased circulating nonesterified fatty acids; and increased IMCLs, diacylglycerols, and ceramides. Perhaps more importantly, inhibition of mitochondrial FAO also initiates a local, adaptive response in muscle that invokes mitochondrial biogenesis, compensatory peroxisomal fat oxidation, and amino acid catabolism. Loss of its major fuel source (lipid) induces an energy deprivation response in muscle coordinated by signaling through AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) to maintain energy supply for locomotion and survival. At the whole-body level, these adaptations result in resistance to obesity

    Growth Hormone Reduces the Severity of Fibrosis Associated With Chronic Intestinal Inflammation

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    BACKGROUND & AIMS: Growth hormone (GH) is used to treat growth delay in children with Crohn's disease and in patients with short-bowel syndrome. GH can increase collagen accumulation in intestinal mesenchymal cells, raising concern that GH therapy could exacerbate fibrosis in patients with Crohn's disease. We tested if GH treatment altered inflammation or fibrosis during chronic, experimental granulomatous enterocolitis. METHODS: Ileum and cecum of Lewis rats were subserosally injected with peptidoglycan-polysaccharide (PG-APS) or control human serum albumin. At the onset of chronic PG-APS-induced inflammation, rats were administered recombinant human GH or vehicle for 14 days. Fibrosis and inflammation were quantified by gross gut disease scoring, histologic scoring, type I collagen, and cytokine expression in cecum. Abundance and localization of suppressor of cytokine signaling-3 (SOCS-3) messenger RNA and/or protein were determined in cecum. Effect of GH, cytokines, or PG-APS on SOCS-3 synthesis was measured in intestinal myofibroblasts. Myofibroblasts overexpressing SOCS-3 were used to test whether SOCS-3 inhibits collagen accumulation. RESULTS: In PG-APS-injected rats, GH modestly reduced gross adhesions and mesenteric contractions, cecal fibrosis score, and collagen expression, but had no effect on intestinal inflammation. GH increased SOCS-3 messenger RNA and protein abundance in PG-APS rats and SOCS-3 messenger RNA was localized to the periphery of granulomas. GH in combination with cytokines or PG-APS, but not alone, induced SOCS-3 synthesis in intestinal myofibroblasts. Myofibroblasts overexpressing SOCS-3 showed reduced cytokine-induced collagen accumulation. CONCLUSIONS: GH modestly reduces intestinal fibrosis associated with chronic experimental enterocolitis and stimulates expression of antifibrogenic SOCS-3, suggesting that GH therapy in inflammatory bowel disease should not exacerbate fibrosis

    Enhanced survival and mucosal repair after dextran sodium sulfate–induced colitis in transgenic mice that overexpress growth hormone

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    AbstractBackground & Aims: Growth hormone (GH) is used as therapy for inflammatory bowel disease (IBD), but the specific effects on intestine are unknown. Transgenic mice overexpressing GH (MT1-bGH-TG) were used to test whether increased plasma GH levels alter inflammation or crypt damage during dextran sodium sulfate (DSS)-induced colitis. Methods: MT1-bGH-TG and wild-type (WT) littermates were given 3% DSS for 5 days followed by up to 10 days of recovery. Colitis and epithelial cell proliferation were evaluated histologically. Plasma insulin-like growth factor (IGF)-I and colonic IGF-I, interleukin (IL)-1β, and intestinal trefoil factor (ITF) messenger RNAs (mRNAs) were measured. Results: DSS induced similar disease onset in MT1-bGH-TG and WT. More MT1-bGH-TG survived than WT. By recovery day 7, MT1-bGH-TG had less inflammation and crypt damage, elevated plasma IGF-I, and increased colonic ITF expression relative to WT. Colonic IL-1β was elevated in DSS-treated MT1-bGH-TG and WT, but IL-1β mRNA abundance correlated with disease only in WT. MT1-bGH-TG showed earlier increases in epithelial cell proliferation than WT during recovery but only WT showed atypical repair. Conclusions: GH does not alter susceptibility to acute DSS-induced colitis but enhances survival, remission of inflammation, and mucosal repair during recovery. GH therapy may be beneficial during active IBD by improving mucosal repair.GASTROENTEROLOGY 2001;120:925-93

    Use of POES SEM-2 observations to examine radiation belt dynamics and energetic electron precipitation into the atmosphere

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    The coupling of the Van Allen radiation belts to the Earth's atmosphere through precipitating particles is an area of intense scientific interest. Currently, there are significant uncertainties surrounding the precipitating characteristics of medium energy electrons (> 20 keV), and even more uncertainties for relativistic electrons. In this paper we examine roughly 10 years of measurements of trapped and precipitating electrons available from the Polar Orbiting Environmental Satellites (POES)/Space Environment Monitor (SEM-2), which has provided long-term global data in this energy range. We show that the POES SEM-2 detectors suffer from some contamination issues that complicate the understanding of the measurements, but that the observations provide insight into the precipitation of energetic electrons from the radiation belts, and may be developed into a useful climatology for medium energy electrons. Electron contamination also allows POES/SEM-2 to provide unintended observations of > 700 keV relativistic electrons. Finally, there is an energy-dependent time delay observed in the POES/SEM-2 observations, with the relativistic electron enhancement (electrons > 800 keV) delayed by approximately one week relative to the > 30 keV electron enhancement, probably due to the timescales of the acceleration processes. Observations of trapped relativistic electron fluxes near the geomagnetic equator by GOES show similar delays, indicating a "coherency" to the radiation belts at high and low orbits, and also a strong link between trapped and precipitating particle fluxes. Such large delays should have consequences for the timing of the atmospheric impact of geomagnetic storms

    Reticulated origin of domesticated emmer wheat supports a dynamic model for the emergence of agriculture in the fertile crescent

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    We used supernetworks with datasets of nuclear gene sequences and novel markers detecting retrotransposon insertions in ribosomal DNA loci to reassess the evolutionary relationships among tetraploid wheats. We show that domesticated emmer has a reticulated genetic ancestry, sharing phylogenetic signals with wild populations from all parts of the wild range. The extent of the genetic reticulation cannot be explained by post-domestication gene flow between cultivated emmer and wild plants, and the phylogenetic relationships among tetraploid wheats are incompatible with simple linear descent of the domesticates from a single wild population. A more parsimonious explanation of the data is that domesticated emmer originates from a hybridized population of different wild lineages. The observed diversity and reticulation patterns indicate that wild emmer evolved in the southern Levant, and that the wild emmer populations in south-eastern Turkey and the Zagros Mountains are relatively recent reticulate descendants of a subset of the Levantine wild populations. Based on our results we propose a new model for the emergence of domesticated emmer. During a pre-domestication period, diverse wild populations were collected from a large area west of the Euphrates and cultivated in mixed stands. Within these cultivated stands, hybridization gave rise to lineages displaying reticulated genealogical relationships with their ancestral populations. Gradual movement of early farmers out of the Levant introduced the pre-domesticated reticulated lineages to the northern and eastern parts of the Fertile Crescent, giving rise to the local wild populations but also facilitating fixation of domestication traits. Our model is consistent with the protracted and dispersed transition to agriculture indicated by the archaeobotanical evidence, and also with previous genetic data affiliating domesticated emmer with the wild populations in southeast Turkey. Unlike other protracted models, we assume that humans played an intuitive role throughout the process.Natural Environment Research Council [NE/E015948/1]; Slovak Research and Development Agency [APVV-0661-10, APVV-0197-10]info:eu-repo/semantics/publishedVersio

    An Overview of the 2014 ALMA Long Baseline Campaign

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    A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to make accurate images with resolutions of tens of milliarcseconds, which at submillimeter (submm) wavelengths requires baselines up to ~15 km. To develop and test this capability, a Long Baseline Campaign (LBC) was carried out from September to late November 2014, culminating in end-to-end observations, calibrations, and imaging of selected Science Verification (SV) targets. This paper presents an overview of the campaign and its main results, including an investigation of the short-term coherence properties and systematic phase errors over the long baselines at the ALMA site, a summary of the SV targets and observations, and recommendations for science observing strategies at long baselines. Deep ALMA images of the quasar 3C138 at 97 and 241 GHz are also compared to VLA 43 GHz results, demonstrating an agreement at a level of a few percent. As a result of the extensive program of LBC testing, the highly successful SV imaging at long baselines achieved angular resolutions as fine as 19 mas at ~350 GHz. Observing with ALMA on baselines of up to 15 km is now possible, and opens up new parameter space for submm astronomy.Comment: 11 pages, 7 figures, 2 tables; accepted for publication in the Astrophysical Journal Letters; this version with small changes to affiliation

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Has Selection for Improved Agronomic Traits Made Reed Canarygrass Invasive?

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    Plant breeders have played an essential role in improving agricultural crops, and their efforts will be critical to meet the increasing demand for cellulosic bioenergy feedstocks. However, a major concern is the potential development of novel invasive species that result from breeders' efforts to improve agronomic traits in a crop. We use reed canarygrass as a case study to evaluate the potential of plant breeding to give rise to invasive species. Reed canarygrass has been improved by breeders for use as a forage crop, but it is unclear whether breeding efforts have given rise to more vigorous populations of the species. We evaluated cultivars, European wild, and North American invader populations in upland and wetland environments to identify differences in vigor between the groups of populations. While cultivars were among the most vigorous populations in an agricultural environment (upland soils with nitrogen addition), there were no differences in above- or below-ground production between any populations in wetland environments. These results suggest that breeding has only marginally increased vigor in upland environments and that these gains are not maintained in wetland environments. Breeding focuses on selection for improvements of a specific target population of environments, and stability across a wide range of environments has proved elusive for even the most intensively bred crops. We conclude that breeding efforts are not responsible for wetland invasion by reed canarygrass and offer guidelines that will help reduce the possibility of breeding programs releasing cultivars that will become invasive
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