Person:
Pérez Gutiérrez, José Félix

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First Name
José Félix
Last Name
Pérez Gutiérrez
URI
https://hdl.handle.net/20.500.14352/80379
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Veterinaria
Department
Medicina y Cirugía Animal
Area
Medicina y Cirugía Animal
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1990 - 199912010 - 20201
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Author: Pérez Gutiérrez, José Félix ×

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    Cryopreservation effects on canine sperm morphometric variables and ultrastructure: comparison between vitrification and conventional freezing
    (Cryobiology, 2020) Cerdeira Lozano, Joaquín Vicente; Sánchez Calabuig, María Jesús; Pérez Gutiérrez, José Félix; Hijon, M.; Castaño, C.; Santiago Moreno, Julián
    Semen cryopreservation is an increasingly demanded technique in canids, particularly in order to preserve and spread high genetic value material. Sperm vitrification may represent an interesting alternative to costly and time consuming conventional freezing. The objective of this study was to evaluate the effect of sperm vitrification on sperm morphometry and ultrastructure compared to conventional freezing. Pools of nine beagle dogs were both frozen and vitrified. Computerized morphological parameters (length, wide, area and perimeter) and sperm ultrastructure, using scanning and transmission microscopy, were analysed in both fresh and in thawed/warmed samples. There were no differences (p > 0.05) between post-thaw and fresh morphometric variables of the sperm heads. However, cluster analysis revealed that sperm-heads turned out to be smaller after thawing (p < 0.05) in two of the four subpopulations. Vitrification-warming process led to an overall increase in sperm-head size. Furthermore, the sperm head size increased after warming in two subpopulations (p < 0.05). In conclusion, the variations in the sperm head area depended on the cryopreservation procedure (conventional freezing or vitrification). Conventional freezing tended to decrease the head dimensions, at least in some subpopulations, and vitrification led to an overall increase in the sperm head size. Decondensation of chromatin and plasma membrane blebbing in the head region was observed by transmission electron microscopy in several vitrified sperm, which might explain the increase of head dimensions detected by CASA-Morph system.
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    Distribución de los estrógenos sintéticos aplicados por técnicas mesoterápicas
    (Medicina Holística, 1990) Pérez Gutiérrez, José Félix; Fontanillas Pérez, Juan Carlos; García Botey, Concepción; Mayenco Aguirre, Ana María
    La aplicación de estrógenos para el control de la reproducción canina y determinadas patologías sexuales de las hembras domésticas, supone un factor de riesgo desencadenante de hipoplásia y aplasia medular, trastornos hepáticos, alteraciones fetales, etc. Mediante la aplicación de estrógenos por vía mesoterápica se busca una fármaco-cinética distinta que evite la biotransformación de los estrógenos epor vía hepática y digestiva, a la vez que menores dosis para conseguir respuestas positivas, a los test biológicos de distribución estrogénica en conejas ovariohisterectomizadas.