5,629 research outputs found

    Connexin 40 promoter-based enrichment of embryonic stem cell-derived cardiovascular progenitor cells

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    Background: Pluripotent embryonic stem (ES) cells that can differentiate into functional cardiomyocytes as well as vascular cells in cell culture may open the door to cardiovascular cell transplantation. However, the percentage of ES cells in embryoid bodies (EBs) which spontaneously undergo cardiovascular differentiation is low (< 10%), making strategies for their specific labeling and purification indispensable. Methods: The human connexin 40 (Cx40) promoter was isolated and cloned in the vector pEGFP. The specificity of the construct was initially assessed in Xenopus embryos injected with Cx40-EGFP plasmid DNA. Stable Cx40-EGFP ES cell clones were differentiated and fluorescent cells were enriched manually as well as via fluorescence-activated cell sorting. Characterization of these cells was performed with respect to spontaneous beating as well as via RT-PCRs and immunofluorescent stainings. Results: Cx40-EGFP reporter plasmid injection led to EGFP fluorescence specifically in the abdominal aorta of frog tadpoles. After crude manual enrichment of highly Cx40-EGFP- positive EBs, the appearance of cardiac and vascular structures was increased approximately 3-fold. Immuno fluorescent stainings showed EGFP expression exclusively in vascular-like structures simultaneously expressing von Willebrand factor and in formerly beating areas expressing alpha-actinin. Cx40-EGFP-expressing EBs revealed significantly higher numbers of beating cardiomyocytes and vascular-like structures. Semiquantitative RT-PCRs confirmed an enhanced cardiovascular differentiation as shown for the cardiac markers Nkx2.5 and MLC2v, as well as the endothelial marker vascular endothelial cadherin. Conclusions: Our work shows the feasibility of specific labeling and purification of cardiovascular progenitor cells from differentiating EBs based on the Cx40 promoter. We provide proof of principle that the deleted CD4 (Delta CD4) surface marker-based method for magnetic cell sorting developed by our group will be ideally suitable for transference to this promoter. Copyright (c) 2008 S. Karger AG, Basel

    Recombinant Human Insulin in Global Diabetes Management – Focus on Clinical Efficacy

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    Biosynthetic human insulin and insulin analogues are the mainstay of insulin therapy for both type 1 and type 2 diabetes although access to human insulin at affordable prices remains a global issue. The world is experiencing an exponential rise in the prevalence of diabetes presenting an urgent need to establish effective diabetes therapy in countries burdened by inadequate health care budgets, malnutrition and infectious diseases. Recombinant human insulin has replaced animal insulins and animal-based semisynthetic human insulin thereby available in sufficient quantities and at affordable prices able to provide global access to insulin therapy. In many patients, analog insulins can offer additional clinical benefit, although at a considerably higher price thus severely restricting availability in low income countries. The approval process for recombinant human insulins (i.e. biosimilars) and analogue insulins is highly variable in the developing countries in contrast to Europe and in North America, where it is well established within a strict regulatory framework. This review aims to discuss the future access to human insulin therapy in a global context with an ever increasing burden of diabetes and significant economic implications

    Evolution of priorities in strategic funding for collaborative health research. A comparison of the European Union Framework Programmes to the program funding by the United States National Institutes of Health

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    The historical research-funding model, based on the curiosity and academic interests of researchers, is giving way to new strategic funding models that seek to meet societal needs. We investigated the impact of this trend on health research funded by the two leading funding bodies worldwide, i.e. the National Institutes of Health (NIH) in the United States, and the framework programs of the European Union (EU). To this end, we performed a quantitative analysis of the content of projects supported through programmatic funding by the EU and NIH, in the period 2008-2014 and 2015-2020. We used machine learning for classification of projects as basic biomedical research, or as more implementation directed clinical therapeutic research, diagnostics research, population research, or policy and management research. In addition, we analyzed funding for major disease areas (cancer, cardio-metabolic and infectious disease). We found that EU collaborative health research projects clearly shifted towards more implementation research. In the US, the recently implemented UM1 program has a similar profile with strong clinical therapeutic research, while other NIH programs remain heavily oriented to basic biomedical research. Funding for cancer research is present across all NIH and EU programs, and in biomedical as well as more implementation directed projects, while infectious diseases is an emerging theme. We conclude that demand for solutions for medical needs leads to expanded funding for implementation- and impact-oriented research. Basic biomedical research remains present in programs driven by scientific initiative and strategies based on excellence, but may be at risk of declining funding opportunities

    Basal conditions of two Transantarctic Mountains outlet glaciers from observation-constrained diagnostic modelling

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    This is the published version. Copyright 2014 International Glaciological SocietyWe present a diagnostic glacier flowline model parameterized and constrained by new velocity data from ice-surface GPS installations and speckle tracking of TerraSAR-X satellite images, newly acquired airborne-radar data, and continental gridded datasets of topography and geothermal heat flux, in order to better understand two outlet glaciers of the East Antarctic ice sheet. Our observational data are employed as primary inputs to a modelling procedure that first calculates the basal thermal regime of each glacier, then iterates the basal sliding coefficient and deformation rate parameter until the fit of simulated to observed surface velocities is optimized. We find that the two glaciers have both frozen and thawed areas at their beds, facilitating partial sliding. Glacier flow arises from a balance between sliding and deformation that fluctuates along the length of each glacier, with the amount of sliding typically varying by up to two orders of magnitude but with deformation rates far more constant. Beardmore Glacier is warmer and faster-flowing than Skelton Glacier, but an up-glacier deepening bed at the grounding line, coupled with ice thicknesses close to flotation, lead us to infer a greater vulnerability of Skelton Glacier to grounding-line recession if affected by ocean-forced thinning and concomitant acceleration

    Determining conductivity and mobility values of individual components in multiphase composite Cu_(1.97)Ag_(0.03)Se

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    The intense interest in phase segregation in thermoelectrics as a means to reduce the lattice thermal conductivity and to modify the electronic properties from nanoscale size effects has not been met with a method for separately measuring the properties of each phase assuming a classical mixture. Here, we apply effective medium theory for measurements of the in-line and Hall resistivity of a multiphase composite, in this case Cu_(1.97) Ag_(0.03)Se. The behavior of these properties with magnetic field as analyzed by effective medium theory allows us to separate the conductivity and charge carrier mobility of each phase. This powerful technique can be used to determine the matrix properties in the presence of an unwanted impurity phase, to control each phase in an engineered composite, and to determine the maximum carrier concentration change by a given dopant, making it the first step toward a full optimization of a multiphase thermoelectric material and distinguishing nanoscale effects from those of a classical mixture
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