39 research outputs found

    Autoévaluation

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    NHE3 activity and trafficking depend on the state of actin organization in proximal tubule

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    The present study was addressed to define the contribution of cytoskeleton elements in the kidney proximal tubule Na+/H+exchanger 3 (NHE3) activity under basal conditions. We used luminal membrane vesicles (LMV) isolated from suspensions of rat cortical tubules pretreated with either colchicine (Colch) or cytochalasin D (Cyto D). Colch pretreatment of suspensions (200 μM for 60 min) moderately decreased LMV NHE3 activity. Cyto D pretreatment (1 μM for 60 min) elicited an increase in LMV NHE3 transport activity but did not increase Na-glucose cotransport activity. Cyto D pretreatment of suspensions did not change the apparent affinity of NHE3 for internal H+. In contrast, after Cyto D pretreatment of the suspensions, NHE3 protein abundance was increased in LMV and remained unchanged in cortical cell homogenates. The effect of Cyto D on NHE3 was further assessed with cultures of murine cortical cells. The amount of surface biotinylated NHE3 increased on Cyto D treatment, whereas NHE3 protein abundance was unchanged in cell homogenates. In conclusion, under basal conditions NHE3 activity depends on the state of actin organization possibly involved in trafficking processes between luminal membrane and intracellular compartment.</jats:p

    A reaction norm model for genomic selection using high-dimensional genomic and environmental data

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    In most agricultural crops the effects of genes on traits are modulated by environmental conditions, leading to genetic by environmental interaction (G × E). Modern genotyping technologies allow characterizing genomes in great detail and modern information systems can generate large volumes of environmental data. In principle, G × E can be accounted for using interactions between markers and environmental covariates (ECs). However, when genotypic and environmental information is high dimensional, modeling all possible interactions explicitly becomes infeasible. In this article we show how to model interactions between high-dimensional sets of markers and ECs using covariance functions. The model presented here consists of (random) reaction norm where the genetic and environmental gradients are described as linear functions of markers and of ECs, respectively. We assessed the proposed method using data from Arvalis, consisting of 139 wheat lines genotyped with 2,395 SNPs and evaluated for grain yield over 8 years and various locations within northern France. A total of 68 ECs, defined based on five phases of the phenology of the crop, were used in the analysis. Interaction terms accounted for a sizable proportion (16 %) of the within-environment yield variance, and the prediction accuracy of models including interaction terms was substantially higher (17–34 %) than that of models based on main effects only. Breeding for target environmental conditions has become a central priority of most breeding programs. Methods, like the one presented here, that can capitalize upon the wealth of genomic and environmental information available, will become increasingly important

    Consensus on circulatory shock and hemodynamic monitoring. Task force of the European Society of Intensive Care Medicine.

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    OBJECTIVE: Circulatory shock is a life-threatening syndrome resulting in multiorgan failure and a high mortality rate. The aim of this consensus is to provide support to the bedside clinician regarding the diagnosis, management and monitoring of shock. METHODS: The European Society of Intensive Care Medicine invited 12 experts to form a Task Force to update a previous consensus (Antonelli et al.: Intensive Care Med 33:575-590, 2007). The same five questions addressed in the earlier consensus were used as the outline for the literature search and review, with the aim of the Task Force to produce statements based on the available literature and evidence. These questions were: (1) What are the epidemiologic and pathophysiologic features of shock in the intensive care unit ? (2) Should we monitor preload and fluid responsiveness in shock ? (3) How and when should we monitor stroke volume or cardiac output in shock ? (4) What markers of the regional and microcirculation can be monitored, and how can cellular function be assessed in shock ? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock ? Four types of statements were used: definition, recommendation, best practice and statement of fact. RESULTS: Forty-four statements were made. The main new statements include: (1) statements on individualizing blood pressure targets; (2) statements on the assessment and prediction of fluid responsiveness; (3) statements on the use of echocardiography and hemodynamic monitoring. CONCLUSIONS: This consensus provides 44 statements that can be used at the bedside to diagnose, treat and monitor patients with shock
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