980 resultados para OUTER-MEMBRANE INTEGRITY


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Medicina Veterinária - FMVZ

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Pós-graduação em Medicina Veterinária - FMVZ

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The aim of this study was to evaluate the association between cryoprotectants little studied in Brazil such as dimethylformamide and trehalose amid thinner, using protocols of fast and slow defrosting. Three adult Labrador Retrievier male, healthy dogs, weekly submitted to one semen collection during five-weeks period, were used. The base diluent medium used in this study was tris-citrate added with 3% of dimethylformamide + 3% glycerol (D1), 3% dimethylformamide and trehalose (D2) and 4% glycerol (D3). At defrosting, half of the semen samples from each diluent medium was defrosted by rapid method in water-bath at 75 °C for seven minutes, followed by a new immersion at 37 °C for 1 minute. The other half of the samples was defrosted by slow method, in water-bath at 37 °C for 1 minute. The semen was evaluated for sperm progressive motility and vigor, besides membrane integrity. For this, the semen samples were submitted to either hyposmotic and membrane integrity tests of the plasmatic membrane and acrosome (fluorescence). The results indicated that the use of glycerol as cryoprotector in TRIS diluter provides greater efficacy in cryopreserving spermatozoa of the canine species, when compared to dimethylformamide associated with trehalose or glycerol.

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Pós-graduação em Medicina Veterinária - FMVZ

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Cryopreservation of sperm is important to preserve the gerrnplasm from animals of genetic value, which can die unexpectedly. This study compares conventional and automated methods of cryopreservation of spermatozoa obtained from the epididymis of bulls post-mortem. Twenty-two epididymides were obtained from a commercial slaughterhouse. Spermatozoa were collected from the tail of the epididymis using the retrograde flow technique. Thus, the samples, which were diluted in 10 ml of extender without glycerol (Botubov (R) I, Botupharma, Botucatu, SP, Brazil), were evaluated on motility, sperm vigor, structural and functional (swelling hypoosmotic test) membrane integrity, mitochondrial activity, sperm viability and ADN fragmentation. The samples were divided into two aliquots and diluted in extender with glycerol (Botubov (R) II, Botupharma, Botucatu, SP, Brazil) at a concentration of 50x10(6) motile sperm/0.5 French straws. One sample was frozen by the conventional method (4 hours at 5 degrees C, in a refrigerator and 20 min in nitrogen vapor) and the other by the automated method (Cryogen (R) Dualflex, Neovet, Uberaba, MG, Brazil). The parameters were higher in all the tests of fresh sperm samples, with the exception of the swelling hypoosmotic test, which showed no significant difference when the results were compared with sperm frozen by the conventional method. The average motility of fresh spermatozoa was 74%, and conventional and automated averages were 29 and 25%, respectively. Therefore, although cryopreservation techniques reduce sperm quality parameters, the viability of the sperm is maintained, and these methods can be used to preserve sperm.

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The objective of this study was to evaluate alternatives in small volumes to conventional gradient of Percoll((R)) on semen quality, in vitro embryo production, sex ratio and embryo survival after vitrification. Thawed semen was randomly allocated to one of four density gradient selection methods: (1) conventional Percoll((R)) (P), (2) MiniPercoll (MP), (3) MiniIsolate (MI), and (4) MiniOptiprep (MO). Sperm kinetics and quality were evaluated. Use of P, MP and MI gradients did not affect sperm motility (P > 0.05). However, there was a decrease in total and progressive sperm motility in MO (70.8 and 51.3% vs. 87.3 and 69.5% for P; 87.3 and 73% for MP; 92.3 and 78.8% for MI; P < 0.05). The MO had lower membrane integrity compared with P, MP and MI (39.7 vs. 70.5, 72.3, 63.8%, respectively, P < 0.05). The percentage of blastocysts produced was higher in MI than in MP and MO (21.1 vs. 16.1 and 16.9%, P < 0.05) and similar to P (18.4%; P > 0.05). Sex ratio and embryo survival after vitrification were similar among groups (P > 0.05). Semen selected by Isolate and Optiprep gradient, at the concentrations and small volumes used, demonstrated similar characteristics and in vitro embryo production to conventional Percoll((R)) gradient.

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