953 resultados para vieillissement normal


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The presence of heparin and a mixture of penicillamine, hypotaurine, and epinephrine (PHE) solution in the in vitro fertilization (IVF) media seem to be a prerequisite when bovine spermatozoa are capacitated in vitro, in order to stimulate sperm motility and acrosome reaction. The present study was designed to determine the effect of the addition of heparin and PHE during IVF on the quality and penetrability of spermatozoa into bovine oocytes and on subsequent embryo development. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes and mitochondrial function, was diminished (P < 0.05) in the presence of heparin and PHE. Oocyte penetration and normal pronuclear formation rates, as well as the percentage of zygotes presenting more than two pronuclei, was higher (P < 0.05) in the presence of heparin and PHE. No differences were observed in cleavage rates between treatment and control (P > 0.05). However, the developmental rate to the blastocyst stage was increased in the presence of heparin and PHE (P > 0.05). The quality of embryos that reached the blastocyst stage was evaluated by counting the inner cell mass (ICM) and trophectoderm (TE) cell numbers and total number of cells; the percentage of ICM and TE cells was unaffected (P > 0.05) in the presence of heparin and PHE (P < 0.05). In conclusion, this study demonstrated that while the supplementation of IVF media with heparin and PHE solution impairs spermatozoa quality, it plays an important role in sperm capacitation, improving pronuclear formation, and early embryonic development. © 2013 The Society for In Vitro Biology.

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Las consecuencias sociales del envejecimiento son múltiples y suele admitirse que una de ellas es el aumento de la carga que pesa sobre la población activa, especialmente en el contexto de creciente urbanización como es el de Uruguay. La gran mayoría de los jubilados trabaja ante la recepción de pensiones insuficientes para vivir. El envejecimiento de la población se ha visto agravado por la enorme emigración selectiva que compromete a personas en edad activa. Sin embargo, se observan transformaciones importantes en el país que remiten al enorme aumento de la tasa de participación femenina y al aumento de las familias extensas, como dos mecanismos para hacer frente a las condiciones de vida. Estos cambios tienden a fortificar el papel de los ancianos como suplentes de los padres en el hogar.

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Educação Escolar - FCLAR

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Educação Matemática - IGCE

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Documento de Sala de Conferencia, No 2 y No 2, Add.1

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Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)