409 research outputs found

    Utilidad de la antitrombina III en la detección de coagulopatías asociadas a anemias hemolíticas en animales críticos

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    En este trabajo se describe el resultado de la determinación de antitrombina III (ATIII) en veintitrés casos de anemia hemolítica asociada a estados de hipercoagulabilidad sanguínea. El 74% de los pacientes presentaron tasas bajas de ATIII y por lo tanto presentaban riesgos de desarrollar trombosis o coagulaciones intravasculares diseminadas (CID).

    Enlace de encuestas: una propuesta metodológica y aplicación a la encuesta de presupuestos de tiempo

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    Tratamos el problema de completar dos ficheros con registros conteniendo un subconjunto común de variables. La técnica investigada utiliza árboles de regresión y/o clasificación. Se propone y estudia una extensión para variables respuesta multivariantes, ilustrando su empleo sobre la Encuesta de Presupuestos de Tiempo (EPT-93)

    Modeling Nonconfined Density Currents Using 3D Hydrodynamic Models

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    Density currents generated by marine brine discharges, e.g., from desalination plants, can have a negative impact on marine ecosystems. It is therefore important to accurately predict their behavior. Predictions are often made using computational hydrodynamic models, which should be validated using field or laboratory measurements. This paper focuses on the setup and validation of three-dimensional (3D) models for estimating the transport and mixing processes that occur in these types of flows. Through a comprehensive sensitivity analysis based on the reproduction of several laboratory-generated density currents, a set of recommendations are made regarding the modeling aspects, including the domain discretization, the treatment of momentum at the density current source, the hydrostatic hypothesis and the selection of turbulence closure models. Finally, the proposed numerical model setup is validated using different experimental data showing good agreement in terms of the main variables considered: errors of less than 1.3% for dilution and of 6% for velocity. This study serves as a first step toward the full validation of these 3D hydrodynamic models for the simulation of field-scale density currents.This study was partially funded by the Ministry of Economy and Competitiveness (MINECO) under research project TRA2011-28900 (PLVMA3D). B. Pérez-Díaz would like to thank MINECO for providing funding under the FPI Program (research fellowship, reference number BES-2012-053693) and the Coasts and Ocean Group of HRWallingford for their assistance with numerical tasks

    B-Function Expression in the Flower Center Underlies the Homeotic Phenotype of Lacandonia schismatica (Triuridaceae)

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    Spontaneous homeotic transformations have been described in natural populations of both plants and animals, but little is known about the molecular-genetic mechanisms underlying these processes in plants. In the ABC model of floral organ identity in Arabidopsis thaliana, the B- and C-functions are necessary for stamen morphogenesis, and C alone is required for carpel identity. We provide ABC model-based molecular-genetic evidence that explains the unique inside-out homeotic floral organ arrangement of the monocotyledonous mycoheterotroph species Lacandonia schismatica (Triuridaceae) from Mexico. Whereas a quarter million flowering plant species bear central carpels surrounded by stamens, L. schismatica stamens occur in the center of the flower and are surrounded by carpels. The simplest explanation for this is that the B-function is displaced toward the flower center. Our analyses of the spatio-temporal pattern of B- and C-function gene expression are consistent with this hypothesis. The hypothesis is further supported by conservation between the B-function genes of L. schismatica and Arabidopsis, as the former are able to rescue stamens in Arabidopsis transgenic complementation lines, and Ls-AP3 and Ls-PI are able to interact with each other and with the corresponding Arabidopsis B-function proteins in yeast. Thus, relatively simple molecular modifications may underlie important morphological shifts in natural populations of extant plant taxa

    GD3 synthase overexpression sensitizes hepatocarcinoma cells to hypoxia and reduces tumor growth by suppressing the cSrc/NF-κB survival pathway

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Background]: Hypoxia-mediated HIF-1a stabilization and NF-kB activation play a key role in carcinogenesis by fostering cancer cell survival, angiogenesis and tumor invasion. Gangliosides are integral components of biological membranes with an increasingly recognized role as signaling intermediates. In particular, ganglioside GD3 has been characterized as a proapoptotic lipid effector by promoting cell death signaling and suppression of survival pathways. Thus, our aim was to analyze the role of GD3 in hypoxia susceptibility of epatocarcinoma cells and in vivo tumor growth.[Methodology/Principal Findings]: We generated and characterized a human hepatocarcinoma cell line stably expressing GD3 synthase (Hep3B-GD3), which catalyzes the synthesis of GD3 from GM3. Despite increased GD3 levels (2–3 fold), no significant changes in cell morphology or growth were observed in Hep3B-GD3 cells compared to wild type Hep3B cells under normoxia. However, exposure of Hep3B-GD3 cells to hypoxia (2% O2) enhanced reactive oxygen species (ROS) generation, resulting in decreased cell survival, with similar findings observed in Hep3B cells exposed to increasing doses of exogenous GD3. In addition, hypoxia-induced c-Src phosphorylation at tyrosine residues, NF-kB activation and subsequent expression of Mn-SOD were observed in Hep3B cells but not in Hep3B-GD3 cells. Moreover, MnTBAP, an antioxidant with predominant SOD mimetic activity, reduced ROS generation, protecting Hep3B-GD3 cells from hypoxia-induced death. Finally, lower tumor growth, higher cell death and reduced Mn-SOD expression were observed in Hep3B-GD3 compared to Hep3B tumor xenografts.[Conclusion]: These findings underscore a role for GD3 in hypoxia susceptibility by disabling the c-Src/NF-kB survival pathway resulting in lower Mn-SOD expression, which may be of relevance in hepatocellular carcinoma therapy.Grant support: CIBEREHD and grants FIS06/0395, FIS07/1039, SAF2006-06789 and SAF2008-02199 by Instituto de Salud Carlos III and Ministry of Science and Innovation from Spain, and from the Research Center for Liver and Pancreatic Diseases, P50-AA-11999 funded by the US National Institute on Alcohol Abuse and Alcoholism.Peer reviewe

    Aging impairs the hepatic subcellular distribution of ChREBP in response to fasting/feeding in rats: Implications on hepatic steatosis

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    © 2015 Elsevier Inc. All rights reserved. Aging is associated with alterations of lipid metabolism and increased prevalence of non alcoholic hepatic steatosis.Nevertheless, themechanisms bywhich fat is accumulated in the liver during aging remain incompletely understood. In the present study, we investigated potential alterations that might contribute to the development of hepatic steatosis with aging. To this end, we analyzed the expression and the subcellular localization of key transcriptional factors involved in lipid metabolism such as ChREBP, Foxo1, Foxa2 and SREBP-1c in the liver of 3- and 24-month oldWistar rats. In addition, we studied the intracellular redistribution of ChREBP in response to fasting/refeeding transition. Old rats were characterized by hepatic steatosis, low serum ketone body levels and postprandial hyperinsulinemia. These observations were paralleled by the cytoplasmic localization and decreased expression of Foxa2, while ChREBP expression was markedly up-regulated and mainly localized in the nucleus. Consequently, the expression of lipogenic and β-oxidation genes was up-regulated or downregulated, respectively. Besides, the intracellular redistribution of ChREBP in response to fasting/refeeding transition was also impaired in old animals. Additionally, a negative correlation between serum ketone body levels and the nuclear localization of ChREBP was observed only in adult but not in old rats. Taken together, these data suggest that an age-related dysfunctional adaptation of ChREBP, in response to changes in the nutritional state, might contribute to the development of liver steatosis with aging.Junta de Comunidades de Castilla-La Mancha (JCCM), BFU2012- 39705-C03-01 from Ministerio de Ciencia e Innovación, and S2010/BMC2423 from Comunidad de Madrid, Spain. A.S. was supported by FPU predoctoral fellowship from Ministerio de Educación y Ciencia (MEC), Spain, and B.B. was supported by CONACyT predoctoral fellowship from México. The Centre of Molecular Biology “Severo Ochoa” is the recipient of institutional aid from the Ramón Areces FoundationPeer Reviewe
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