953 resultados para Male-specific SCAR marker (MSM)


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

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Several animal studies have shown that supplementation with specific strains of lactic acid bacteria could prevent the establishment, growth, and metastasis of transplantable and chemically induced tumors. The goal of this study was to determine the effect of Enterococcus faecium CRL 183 on the incidence of colorectal tumors induced experimentally by dimethylhydrazine (DMH). We used thirty 4-week old male Wistar rat. The animals belonging to the DMH groups were injected s.c 20 mg/kg body weight of 1,2 dimethylhydrazine and 1 mM EDTA (pH 6.5), in a weekly dose, for 14 weeks. Three groups were used: (1) Control (not initiated); (2) Initiated with DMH; (3) Initiated with DMH + intake of E. faecium CRL 183. At the end of the 42nd week, all the animals were euthanized; the colons were removed and analyzed histologically. All the groups were compared histologically and IL-4, IFN-gamma and TNF-alpha cytokines. The control group did not develop pre-neoplastic lesions. The E. faecium CRL 183-DMH group showed a 50% inhibition in incidence in average number of tumors (P < 0.001), reduced the formation of ACF (P < 0.001), the lowest number of adenocarcinoma being found in this group (P < 0.001) and enhanced the immune response by increasing IL-4, IFN-gamma and TNF-alpha (P < 0.001) when compared with the DMH group.

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Previous work in our laboratory revealed that the pubertal period of reproductive development in the male rat was particularly vulnerable to gossypol exposure, with a higher frequency of round structures in the lumen of the cauda epididymidis in the treated rats. Herein, we utilized hemicastration and electron microscopy to confirm that the epididymis is a definitive target of gossypol. Although exposure to gossypol from weaning through puberty caused a significant decrease in daily sperm production, as well as in the concentration of sperm in the epididymis, serum testosterone levels and reproductive organ weights were not altered. In gossypol treated rats, sperm morphology was compromised severely, but the epithelium in testis and epididymis appeared morphologically normal. Ultrastructural examination revealed that round structures, present only in gossypol exposed males, represented: (1) principal cells exfoliated from the epididymal epithelium; (2) epididymal epithelial cell cytoplasm containing degenerating sperm; and (3) degenerating epithelial cells, consisting of vesicles and particles of different sizes, forms and densities. Taken together, the data confirm that gossypol targets the epididymis, disturbing both the structure and function of this organ, and presumably disrupts sperm maturation.

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Female Nile tilapia incubate fertilized eggs in their mouth until they are released as alevins. Consequently, the female may not eat during this period. Thus, it would be expected that female Nile tilapia are more adapted to recovering from fasting than males, which do not display this behavior. To test this hypothesis we conducted an experiment with two groups of fish consisting of 7 males and 7 females each, with one fish per aquarium. The experiment was divided into three phases involving adjustment of the animals to experimental aquaria (0-15th day), fasting (16th-27th day), and refeeding (27th-42nd day). Compensatory growth performance was assessed by specific growth rate, weight, food conversion efficiency and food intake. Food conversion efficiency increased after fasting with a similar rate for both sexes. However, specific growth rate, food intake and weight gain (%) were significantly higher in males than in females in the refeeding phase. Thus, we conclude that male Nile tilapia can compensate for a fasting period more efficiently than females, refuting our hypothesis. A possible mechanism involved in the greater male compensation is that they presented greater hyperphagia than females, concomitantly with a similar rate of food conversion efficiency for both sexes during refeeding, which would probably be provoking greater growth in males.

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Selection favors females that attend to reliable information about male genetic quality and fitness. Male nutritional condition can be a significant sign of mate quality since poor nutrition can be related to reduced sperm quality, low sperm quantity, sexually transmitted diseases, and parasites. We tested whether female Nile tilapia, Oreochromis niloticus, preferred the chemical cues of males that were well fed with high-protein diet over those fed with low-protein diet. Females do not only discriminate between males but also show a preference for well-fed males, discriminating between the odors with respect to nutritional state, suggesting that they were responding to a food-specific chemical cue. It is therefore likely that nutritional condition is related to the production of pheromones in males. Our results suggest that information about male nutritional state can be conveyed in chemical cues and that females attend to these cues during mate choice.

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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)

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PURPOSE:To assess whether late introduction of a specific COX-2 inhibitor (Meloxicam) can treat and/or prevent the progression of tumors in the stomach of rats submitted to duodenogastric reflux. METHODS: Seventy five male Wistar rats, weighing 150 grams, were submitted to the induction of duodenogastric reflux through the pylorus. At 36 weeks of follow-up were established three experimental groups: DGR36 sacrificed immediately, DGR54 and DGR54MLX both sacrificed at 54th week of follow-up . The animals of the latter group were fed with a rat chow premixed with Meloxicam (2.0 mg/ kg feed; 0.3 mg / kg bw / day) and the other two with standard rat chow. The lesions found in the pyloric mucosa and gastrojejunal anastomosis were analyzed macroscopically and histologically. For statistical analysis was adjusted a generalized linear model assuming a binomial distribution with LOGIT link function. RESULTS: No significant differences were found when comparing the incidences of benign tumor lesions (Adenomatous Hyperplasia), p=0.4915, or malignant (Mucinous Adenocarcinoma), p=0.2731, among groups. CONCLUSION: Late introduction of specific COX-2 inhibitor (Meloxicam) did not treat and was not able to prevent the progression of tumoral lesions induced by duodenogastric reflux in the rat stomachs.

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Since gonadal denervation and pineal deafferentation by cervical superior ganglionectomy affect sexual development, this study was performed to evaluate testicular steroidogenesis, spermatogenesis and the cervical superior ganglion (CSG) histology in rats treated with guanethidine (GD). The treatment was performed by GD s.c. injections for 3 weeks, from the 21st day of age to the 41st day of age (pre-puberty), when the animals were sacrificed. Different doses were used: group A=10 mg/kg/day, group B=50 mg/kg/day and saline (control group). Testicular denervation was confirmed by HPLC for catecholamines in testicular tissue. Testicular concentrations (TC) of progesterone (P4) and testosterone (T) were measured by RIA. Significantly higher TC of P4 and lower TC of T were observed only in group A in comparison with group B and the control group. No alteration of sperm production was observed in either treated group. Histological analysis of CSG showed only few neuronal alterations in group A rats, while in group B the nervous cells were practically destroyed. This suggests that 10 mg/kg/day GD treatment probably produces a specific blockade of 17 alpha-hydroxylase/17,20 desmolase at pre-puberty leading to a decrease of the androgen production. However, in the 50 mg/kg/day group no differences were observed concerning the steroid profiles, this result being attributed to the extensive damage to the CSG observed only in group B. The CSG destruction causes deafferentation of the pineal gland producing abolishment of the inhibition of the 17 alpha-hydroxylase/17,20 desmolase promoted by melatonin or by an out of phase production of androgen.

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Gossypol, a yellow pigment found in cottonseeds, well known for its antifertility properties in animals, has been used as a contraceptive by men. The aims of this work were to evaluate the effects of gossypol throughout sexual development of male rats and to provide additional data to clarify the target site or sites of this compound in the male reproductive system, Gossypol (15 mg/kg per day) was given to animals from weaning through prepuberty (41 days), early puberty (51 days), puberty (61 days), and sexual maturity (91 days). Ventral prostate weight and fructose levels were similar in control and treated rats, suggesting that androgen levels were normal. No histological effects on the testis were detected, but there was a significant decrease in the sperm concentration in the cauda epididymidis of gossypol-treated animals killed at 61 and 91 days, as well as a significant increase in abnormal sperm in the vas deferens of treated animals. Moreover, the histology of the cauda epididymidis of the rats treated throughout puberty (ie, until days 51 and 61) showed a great number of round bodies in the lumen of the epididymis. These structures stained for the epididymis-specific protein E. Collectively, the data demonstrate that the epididymis is a target of gossypol when postweaning exposure extends throughout pubertal development, and that whereas more subtle histological effects commence around puberty, indicators reproductive competence are compromised in adulthood.

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Specific essential oil (EO) blends and probiotics used as feed additives have been shown to promote healthy digestive microbials resulting in improved poultry production. Two consecutive experiments were conducted with broilers fed corn-soybean meal diets to determine comparative effects of feed additives on ileal and caecal microbial populations (MP). Ross 708 broilers were placed in 84 pens with previously used litter and treatments maintained in the same pens for both experiments. Eight treatment groups were fed diets containing: Bacitracin methylene disalicylate (BMD) as positive control (PC); no additives as negative control (NC); three probiotics: BC-30; BioPlus 2B (B2B); and Calsporin; and the essential oil blends Crina Poultry Plus (CPP) at 300 or 150 ppm in the first experiment; and CPP at 300 ppm and Crina Poultry AF at 100 ppm in experiment 2. Starter and grower diets contained the ionophore (Coban). Ileal and caecal samples were collected at 43 days of age from male broilers. The DNA of microbial populations was isolated from digesta samples and analysed by denaturing gradient gel electrophoresis to generate percentage similarity coefficients (%SC) from band pattern dendrograms. Differences were observed in ileal and caecal populations depending on treatment, respectively, and especially between experiments. Broilers fed diets with probiotics had very similar MP. The EO CPP at 300 ppm resulted in ilea! MP similar to those observed in chickens fed probiotics. We concluded that antibiotic treatment affected ileal, but no caecal MP. More pronounced changes in ileal and caecal MP were seen in broilers at 43 days of age following probiotic and essential oil treatments.