824 research outputs found

    An Endosomal NAADP-Sensitive Two-Pore Ca(2+) Channel Regulates ER-Endosome Membrane Contact Sites to Control Growth Factor Signaling.

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    Membrane contact sites are regions of close apposition between organelles that facilitate information transfer. Here, we reveal an essential role for Ca(2+) derived from the endo-lysosomal system in maintaining contact between endosomes and the endoplasmic reticulum (ER). Antagonizing action of the Ca(2+)-mobilizing messenger NAADP, inhibiting its target endo-lysosomal ion channel, TPC1, and buffering local Ca(2+) fluxes all clustered and enlarged late endosomes/lysosomes. We show that TPC1 localizes to ER-endosome contact sites and is required for their formation. Reducing NAADP-dependent contacts delayed EGF receptor de-phosphorylation consistent with close apposition of endocytosed receptors with the ER-localized phosphatase PTP1B. In accord, downstream MAP kinase activation and mobilization of ER Ca(2+) stores by EGF were exaggerated upon NAADP blockade. Membrane contact sites between endosomes and the ER thus emerge as Ca(2+)-dependent hubs for signaling

    The transcriptional response of Caenorhabditis elegans to ivermectin exposure identifies novel genes involved in the response to reduced food intake

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    We have examined the transcriptional response of Caenorhabditis elegans following exposure to the anthelmintic drug ivermectin (IVM) using whole genome microarrays and real-time QPCR. Our original aim was to identify candidate molecules involved in IVM metabolism and/or excretion. For this reason the IVM tolerant strain, DA1316, was used to minimise transcriptomic changes related to the phenotype of drug exposure. However, unlike equivalent work with benzimidazole drugs, very few of the induced genes were members of xenobiotic metabolising enzyme families. Instead, the transcriptional response was dominated by genes associated with fat mobilization and fatty acid metabolism including catalase, esterase, and fatty acid CoA synthetase genes. This is consistent with the reduction in pharyngeal pumping, and consequential reduction in food intake, upon exposure of DA1316 worms to IVM. Genes with the highest fold change in response to IVM exposure, cyp-37B1, mtl-1 and scl-2, were comparably up-regulated in response to short–term food withdrawal (4 hr) independent of IVM exposure, and GFP reporter constructs confirm their expression in tissues associated with fat storage (intestine and hypodermis). These experiments have serendipitously identified novel genes involved in an early response of C. elegans to reduced food intake and may provide insight into similar processes in higher organisms

    Rationale and study design for a randomised controlled trial to reduce sedentary time in adults at risk of type 2 diabetes mellitus: project stand (Sedentary Time ANd diabetes)

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    <p>Abstract</p> <p>Background</p> <p>The rising prevalence of Type 2 Diabetes Mellitus (T2DM) is a major public health problem. There is an urgent need for effective lifestyle interventions to prevent the development of T2DM. Sedentary behaviour (sitting time) has recently been identified as a risk factor for diabetes, often independent of the time spent in moderate-to-vigorous physical activity. Project STAND (<it>Sedentary Time ANd Diabetes</it>) is a study which aims to reduce sedentary behaviour in younger adults at high risk of T2DM.</p> <p>Methods/Design</p> <p>A reduction in sedentary time is targeted using theory driven group structured education. The STAND programme is subject to piloting and process evaluation in line with the MRC framework for complex interventions. Participants are encouraged to self-monitor and self-regulate their behaviour. The intervention is being assessed in a randomised controlled trial with 12 month follow up. Inclusion criteria are a) aged 18-40 years with a BMI in the obese range; b) 18-40 years with a BMI in the overweight range plus an additional risk factor for T2DM. Participants are randomised to the intervention (n = 89) or control (n = 89) arm. The primary outcome is a reduction in sedentary behaviour at 12 months as measured by an accelerometer (count < 100/min). Secondary outcomes include physical activity, sitting/lying time using the ActivPAL posture monitor, fasting and 2 h oral glucose tolerance test, lipids, inflammatory biomarkers, body weight, waist circumference, blood pressure, illness perceptions, and efficacy beliefs for behaviour change.</p> <p>Conclusions</p> <p>This is the first UK trial to address sedentary behaviour change in a population of younger adults at risk of T2DM. The results will provide a platform for the development of a range of future multidisciplinary interventions in this rapidly expanding high-risk population.</p> <p>Trial registration</p> <p>Current controlled trials <a href="http://www.controlled-trials.com/ISRCTN08434554">ISRCTN08434554</a>, MRC project 91409.</p

    Patients experiences of Polymyalgia Rheumatica: a Qualitative Literature Synthesis Review

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    Background Qualitative research is needed to better understand the concepts of remission and relapse in Polymyalgia Rheumatica (PMR). Remission, relapse, and disease activity have been defined heterogeneously in clinical studies which exclude the patient view leading to a discrepancy between physician and patient perspectives when evaluating disease activity. Aims The present work is part of a project of the PMR Working Group of Outcome Measures in Rheumatology (OMERACT), which is a global, volunteer-driven, non-profit research group aiming to improve outcome measures in rheumatic diseases. We carried out a synthesis of findings from multiple qualitative studies to provide a range and depth of meanings, experiences, and perspectives of participants across health-care contexts to explore the patient perspectives of disease activity in PMR. Methods A professional librarian carried out systematic search of the qualitative research literature across Ovid (Medline), EMBASE and CINAHL to identify studies of interest. Research synthesis was carried out in accordance with the ENTERQ criteria by three researchers with qualitative research experience. Results The search was carried out from each of the database point of inception to 19/10/2023. Review of abstracts, and hand searching reference lists of manuscripts identified 12 studies of interest. There were three main over-arching ideas identified within the published work: 1. Pathway to diagnosis, 2. Managing uncertainty and 3. Challenges to everyday life. Within these three over-arching ideas there were sub-themes identified within the conceptual scaffold which were underpinned with the expression of self and control. The domain of pathway diagnosis included making sense of the condition, normalisation of symptoms and struggles navigating care systems. Within the domain of manging uncertainty where the concepts of self and illness and the positive and negative effects of steroids. The Challenges to everyday life domain comprised day to day living, adaptation and psycho-social burden of disease. Conclusion This research synthesis of qualitative work on PMR has identified three over-arching domains providing a rich narrative of lived experience which point to why discrepancies exist within current physician-focused definitions of remission and relapse. Disclosure Nonspecific to this study

    Personalisation in MOOCs: a critical literature review

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    The advent and rise of Massive Open Online Courses (MOOCs) have brought many issues to the area of educational technology. Researchers in the field have been addressing these issues such as pedagogical quality of MOOCs, high attrition rates, and sustainability of MOOCs. However, MOOCs personalisation has not been subject of the wide discussions around MOOCs. This paper presents a critical literature survey and analysis of the available literature on personalisation in MOOCs to identify the needs, the current states and efforts to personalise learning in MOOCs. The findings illustrate that there is a growing attention to personalisation to improve learners’ individual learning experiences in MOOCs. In order to implement personalised services, personalised learning path, personalised assessment and feedback, personalised forum thread and recommendation service for related learning materials or learning tasks are commonly applied

    Experimental Evidence for Reduced Rodent Diversity Causing Increased Hantavirus Prevalence

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    Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management

    What traits are carried on mobile genetic elements, and why?

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    Although similar to any other organism, prokaryotes can transfer genes vertically from mother cell to daughter cell, they can also exchange certain genes horizontally. Genes can move within and between genomes at fast rates because of mobile genetic elements (MGEs). Although mobile elements are fundamentally self-interested entities, and thus replicate for their own gain, they frequently carry genes beneficial for their hosts and/or the neighbours of their hosts. Many genes that are carried by mobile elements code for traits that are expressed outside of the cell. Such traits are involved in bacterial sociality, such as the production of public goods, which benefit a cell's neighbours, or the production of bacteriocins, which harm a cell's neighbours. In this study we review the patterns that are emerging in the types of genes carried by mobile elements, and discuss the evolutionary and ecological conditions under which mobile elements evolve to carry their peculiar mix of parasitic, beneficial and cooperative genes
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