938 resultados para Reproductive sterilization
Resumo:
OBJECTIVES The effects of advancing paternal age on the male reproductive system are well known, but its effects on fecundity remain controversial. Although oxidative stress is associated with poor semen quality and function, a relationship with advancing male age has not been established. The objective of this study was to analyze the relationship between male age and seminal reactive oxygen species (ROS) levels in men presenting for voluntary sterilization. METHODS We prospectively evaluated 98 fertile men who were candidates for vasectomy. These were divided into 2 age groups: less than 40 years (n = 78) and 40 or more years (n = 20). We used 46 infertile patients as positive controls. Standard semen analysis, seminal leukocyte count and ROS levels were measured in all samples. Fertile men with leukocytospermia were excluded. RESULTS The mean age of the men was 35.1 +/- 5.6 years. Men 40 years and older had significantly higher ROS levels compared with younger men (P < 0.001). We observed a positive correlation between seminal ROS levels and age (r = 0.20; P = 0.040). In addition, ROS was negatively correlated with sperm concentration (r = -0-48; P < 0.001) and motility (r = -0.21; P = 0.030). CONCLUSIONS Reactive oxygen species levels are significant higher in seminal ejaculates of healthy fertile men older than 40 years. ROS levels in whole ejaculate are significantly correlated to age among fertile men. Because ROS are clearly implicated in the pathogenesis of male infertility, these data suggest that delayed fatherhood may reduce the chances of pregnancy as men become progressively less fertile with age.
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We assess the effects of chemical processing, ethylene oxide sterilization, and threading on bone surface and mechanical properties of bovine undecalcified bone screws. In addition, we evaluate the possibility of manufacturing bone screws with predefined dimensions. Scanning electronic microscopic images show that chemical processing and ethylene oxide treatment causes collagen fiber amalgamation on the bone surface. Processed screws hold higher ultimate loads under bending and torsion than the in natura bone group, with no change in pull-out strength between groups. Threading significantly reduces deformation and bone strength under torsion. Metrological data demonstrate the possibility of manufacturing bone screws with standardized dimensions.
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Vitellogenin (Vg) and lipophorin (Lp) are lipoproteins which play important roles in female reproductive physiology of insects. Both are actively taken up by growing oocytes and especially Vg and its receptor are considered as female-specifically expressed. The finding that the fat body of in honey bee (Apis mellifera) drones synthesizes Vg and is present in hemolymph has long been viewed as a curiosity. The recent paradigm change concerning the role played by Vg in honey bee life history, especially social division of labor, has now led us to investigate whether a physiological constellation similar to that seen in female reproduction may also be represented in the male sex. By means of Western blot analysis we could show that both Vg and Lp are present in the reproductive tract of adult drones, including the accessory (mucus) glands, but apparently are not secreted. Furthermore, we analyzed the transcript levels of the genes encoding these proteins (vg and lp), as well as their putative receptors (Amvgr and Amlpr) in fat body and accessory glands. Whereas lp, vg and Amlpr transcript levels decreased with age in both tissues. Amvgr mRNA levels increased with age in fat body. To our knowledge this is the first report that vitellogenin and its receptor are co-expressed in the reproductive system of a male insect. We interpret these findings as a cross-sexual transfer of a social physiological trait, associated with the rewiring of the juvenile hormone/vitellogenin circuitry that occurred in the female sex of honey bees. (C) 2010 Elsevier Ltd. All rights reserved.
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We undertook a field study to determine whether comb cell size affects the reproductive behavior of Varroa destructor under natural conditions. We examined the effect of brood cell width on the reproductive behavior of V. destructor in honey bee colonies, under natural conditions. Drone and worker brood combs were sampled from 11 colonies of Apis mellifera. A Pearson correlation test and a Tukey test were used to determine whether mite reproduction rate varied with brood cell width. Generalized additive model analysis showed that infestation rate increased positively and linearly with the width of worker and drone cells. The reproduction rate for viable mother mites was 0.96 viable female descendants per original invading female. No significant correlation was observed between brood cell width and number of offspring of V. destructor. Infertile mother mites were more frequent in narrower brood cells.
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The total meat yield in a beef cattle production cycle is economically very important and depends on the number of calves born per year or birth season, being directly related to reproductive potential. Accumulated Productivity (ACP) is an index that expresses a cow`s capacity to give birth regularly at a young age and to wean animals of greater body weight. Using data from cattle participating in the ""Program for Genetic Improvement of the Nelore Breed"" (PMGRN - Nelore Brasil), bi-trait analyses were performed using the Restricted Maximum Likelihood method based on an ACP animal model and the following traits: age at first calving (AFC), female body weight adjusted for 365 (BW365) and 450 (BW450) days of age, and male scrotal circumference adjusted for 365 (SC365), 450 (SC450), 550 (SC550) and 730 (SC730) days of age. Median estimated ACP heritability was 0.19 and the genetic correlations with AFC, BW365, BW450, SC365, SC450, SC550 and SC730 were 0.33, 0.70, 0.65, 0.08, 0.07, 0.12 and 0.16, respectively. ACP increased and AFC decreased over time, revealing that the selection criteria genetically improved these traits. Selection based on ACP appears to favor the heaviest females at 365 and 450 days of age who showed better reproductive performance as regards AFC. Scrotal circumference was not genetically associated with ACP. (C) 2007 Elsevier B.V. All rights reserved.
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Contents The aim of this research was to evaluate the efficacy of zinc gluconate associated with dimethyl sulphoxide (DMSO) for chemical neutering in canine males. Fifteen sexually mature male dogs were divided in two groups, named control and treated. An injection was administered to both testicles, at a concentration of 26.2 mg zinc gluconate per ml and 0.5% DMSO in the treated group (11 dogs). The control group was given injections of saline solution (four dogs). Clinical examination and blood collection for a haemogram were done both before and after drug injection. There were 12 spermograms performed to analyse sperm motility, sperm vigour, ejaculate volume, testicle size, pathology and sperm concentrations. Libido was also measured. An ultrasound examination and histopathology were performed at the end of the experiment. Dogs` libido after chemical injection was reduced by over 50%. The spermogram analysis showed final mean results of 14.54% for sperm motility, 0.72 of sperm vigour and 37 150 per million spermatozoa per millilitre, values considered below the necessary levels at which fertilization can occur. Ultrasound and histopathology analyses of testicles for the treated group revealed more intense injuries when compared with the control group, with compromised testicular parenchyma and a decrease of germ cell number leading to total atrophy, indicating that the treatment reduced the fertilizing potential of male dogs, promoting a possible subfertile status.
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Tityus serrulatus is the most venomous scorpion in Brazil. Little is known about the effect of maternal exposure to the venom on fetal development. We investigated the effect of low to moderate doses of the venom (0.3 or 1.0 mg/kg s.c. on either day 5 or day 10 of gestation) on pregnant rats and on their offspring. For dams, we observed their body weight gain and reproductive parameters. For the offspring, we observed their body weight and weight of internal organs and the number of live and dead fetuses, and we investigated whether the venom caused external, visceral, skeletal or histopathological alterations in the offspring. The offspring were examined on gestational day 21. Injection of the venom on gestational day 5 did not change the reproductive parameters of the dams, their weight or fetuses` weight. Rats that received the high dose of the venom (1.0 mg/kg) on gestational day 10 had heavier placentas and heavier fetuses with heavier lungs. Injections on day 10 of gestation did not alter the reproductive parameters of the dams nor their weight gain at either dose. The venom did not cause malformations of the fetal skeleton or viscera and did not delay fetal development with either dose. In conclusion, subcutaneous administration of 0.3 or 1.0 mg/kg T. serrulatus venom to pregnant Wistar rats at either day 5 or day 10 of gestation did not cause maternal or clear fetal toxicity. Subtle increases in placental weight and fetal body and lung weights observed following treatment with 1.0 mg/kg on day 10 of gestation were not associated with histopathological findings. Whether these observations represent a reaction to treatment and, if so, the underlying mechanisms and their toxicological impact remain to be examined further in future studies. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
The objectives were to evaluate the effects of equine chorionic gonadotropin (eCG) supplementation (with or without eCG) and type of ovulatory stimulus (GnRH or ECP) on ovarian follicular dynamics, luteal function, and pregnancies per AI (P/AI) in Holstein cows receiving timed artificial insemination (TAI). On Day 0, 742 cows in a total of 782 breedings, received 2 mg of estradiol benzoate (EB) and one intravaginal progesterone (P4) insert (CIDR). On Day 8, the CIDR was removed, and all cows were given PGF2 alpha and assigned to one of four treatments in a 2 x 2 factorial arrangement: (1) CG: GnRH 48 h later; (2) CE: ECP; (3) EG: eCG + GnRH 48 It later; (4) EE: eCG + ECP. There were significant interactions for eCG x ovulatory stimulus and eCG x BCS. Cows in the CG group were less likely (28.9% vs. 33.8%; P < 0.05) to become pregnant compared with those in the EG group (odds ratio [OR] = 0.28). There were no differences in P/AI between CE and EE cows (30.9% vs. 29.1%; OR = 0.85; P = 0.56), respectively. Thinner cows not receiving eCG had lower P/AI than thinner cows receiving eCG (15.2% vs. 38.0%; OR = 0.20; P < 0.01). Treatment with eCG tended to increase serum progestesterone concentrations during the diestrus following synchronized ovulation (P < 0.10). However, the treatment used to induce ovulation did not affect CL volume or serum progesterone concentrations. In conclusion, both ECP and GnRH yielded comparable P/AI. However, eCG treatment at CIDR removal increased pregnancy rate in cows induced to ovulate with GnRH and in cows with lower BCS. (C) 2009 Elsevier Inc. All rights reserved.
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Non-invasive techniques such as the measurement of fecal steroids are now widely used to monitor reproductive hormones in captive and free-ranging wild-life. These methods offer great advantages and deserve to be used in domestic animals. The aim of the present study was to determine the endocrine profile of dairy goats throughout pregnancy by the quantification of fecal progestins and estrogens and assess its con-elation with serum concentrations. Blood and fecal samples were collected weekly from I I adult, multiparous goats, from mating through pregnancy and 2 weeks post-partum. The extraction of estradiol and progesterone fecal metabolites was performed by dilution in ethanol. The radioimmunoassay (RIA) in solid phase was used to quantify serum 17 beta-estradiol (estradiol) and progesterone, as well as their fecal metabolites. The mean concentrations of both fecal and serum estradiol started to increase between weeks 7 and 11, reached peak values near parturition and then decreased sharply (range: 19.8 +/- 5.8 ng/g of feces to 608.6 +/- 472.4 ng/g of feces and 0.007 +/- 0.005 ng/ml to 0.066 +/- 0.024 ng/ml). An increase in both fecal and blood progestagens occurred in the second week, mean concentrations remained greater until week 20, and then decreased in the last week of gestation and 2 weeks post-partum (range: 108.8 +/- 43.6 ng/g of feces to 3119.5 +/- 2076.9 ng/g of feces and 0. 12 +/- 0.04 ng/ml to 13.10 +/- 4.29 ng/ml). The changes in blood and fecal hormone concentrations were analyzed and compared throughout gestation for each single goat, for each breed and for the whole group. Results indicated that matched values of serum and fecal hormone concentrations were correlated (r = 0.79; p < 0.001 for progesterone and r = 0.84;p < 0.001 for estradiol mean concentrations in the whole group). Regression analysis showed that logarithmic model allows significant prediction of serum from fecal concentrations with an R-2 = 0.729 (y = 0.013 1n x - 0.021) for estradiol and R-2 = 0.788 (y = 3.835 1n x - 18.543) for progesterone. Neither fecal nor serum concentrations were affected by the breed but a significant effect of the number of fetuses on progestin concentrations was found. Therefore, the profiles of progesterone and estradiol fecal metabolites reflect the serum concentrations of the same hormones in pregnant goats. (C) 2006 Elsevier B.V. All rights reserved.
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Early-life environmental events that disrupt the mother-pup relationship may induce profound long-lasting changes on several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces sexual behavior and induces anovulatory estrous cycles in female rats. On the afternoon of proestrus, neonatally handled females show a reduced surge of luteinizing hormone (LH) and an increased content of gonadotropin-releasing hormone in the medial preoptic area (MPOA). In order to detect the possible causes for the reduced ovulation and sexual behavior, the present study aimed to analyze the effects of neonatal handling on noradrenaline (NA) and nitric oxide (NO) levels in the MPOA on the afternoon of proestrus. Neonatal handling reduced MHPG (NA metabolite) levels and MHPG/NA ratio in the MPOA, indicating decreased NAergic activity. Additionally, neonatal handling decreased NO levels, as measured by the metabolites (NO x), nitrite and nitrate in the same period. We may conclude that the neonatal handling procedure decreased activity of the NAergic and NOergic systems in the MPOA during proestrus, which is involved in the control of LH and FSH secretion, and this may possibly explain the anovulatory estrous cycles and reduced sexual behavior of the neonatally handled female rats. Copyright (c) 2007 S. Karger AG, Basel.
Resumo:
Reproductive experience (i.e., pregnancy and lactation) induces physiological changes in mammals. We recently showed that a previous reproductive experience can modulate the activity of dopaminergic hypothalamic systems while decreasing serum prolactin (PRL) levels and oxidative burst activity in peritoneal macrophages. Dopamine receptor antagonists increase serum PRL levels, and both PRL and dopamine receptors might be involved in the modulation of macrophage activity, providing a means of communication between the nervous and immune systems. The present study evaluated the in vitro effects of PRL and the dopamine receptor 02 antagonist domperidone (DOMP) on the peritoneal activity of macrophages from primiparous and multiparous female rats during lactation. Oxidative bursts and phagocytosis in peritoneal macrophages were evaluated by flow cytometry. Primiparous and multiparous Wistar rats, during the period of lactation (i.e., days 5-7 after parturition) were used. Samples of peritoneal fluid from these rats were first incubated with PRL (10 and 100 nM) for different periods of time. The same procedure was repeated to evaluate the effects of DOMP (10 and 100 nM). Our results showed that macrophages from multiparous rats respond more effectively to in vitro incubation with PRL, especially with regard to oxidative bursts and the percentage of phagocytosis. Additionally, these effects were more pronounced after 30 min of incubation. These data suggest that reproductive experience is associated with a reduction in serum PRL levels, and cells in experienced female animals, including their macrophages, become more sensitive to the effects of PRL (C) 2011 Elsevier Ireland Ltd. All rights reserved.
Resumo:
Phthalates are environmental contaminants used in the production of plastics, cosmetics and medical devices. Studies on the effects of phthalates on female reproductive health are particularly sparse and mostly restricted to high-dose exposure in rats. In the present study, pregnant rats were treated with 100 mg/kg-d of di-eta-butyl-phthalate (DBP) or only the vehicle (control group), from GD 12 to GD 20 for evaluation of reproductive outcomes and fetal gonads analysis (F0), and from GD 12 to PND 21 to evaluate reproductive development and function on F1 female offspring. Results showed that all parameters were comparable between groups, although there was a significant increase in the fetal weight after DBP exposure. However, the body weight at birth was normal. Based on these data we can conclude that, in these experimental conditions, DBP did not disturb the reproductive development or function of female rats. (C) 2009 Elsevier Inc. All rights reserved.
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This article describes findings from empirical research examining sterilization applications for miners made to the Family Court of Australia between 1992 and 1999. Original materials and written reports from experts,family members, and judicial officers are used to highlight the dominant discourse and themes. These are compared with historical characterizations of young women with disabilities used during the notorious eugenics period in the first half of the 20th century. The new ways of justifying sterilization use the sanitized language of best interests, silencing constructionist approaches to disability and gender issues. The new ways are reminiscent of the old ways of discrimination, prejudice, and violation.
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I examined age effects on reproduction in the Brown Thornbill Acanthiza pusilla in Canberra, Australia. I found that the reproductive performance of both males and females improved with age, although only age-related improvement in male performance had a significant effect on annual reproductive success. Reproductive success improved with male age as a result of improved performance during two stages of the breeding cycle: first-year males were less likely to fledge young than those aged two or more, while both first and second-year males were less successful at raising fledglings to independence than males of three or more. Male performance appears to improve over three years as they gain experience at provisioning nestlings and caring for fledglings without attracting predators, rather than as a direct result of improved foraging skills. In contrast, reproductive success only improved slightly with female age, although females of two or more years initiated their first clutch earlier in the season than one-year-old females, and tended to be mure likely to re-nest if a breeding attempt failed. The poor performance of young females appears unlikely to be related to their foraging ability but may be associated with costs imposed by dispersing to a breeding vacancy earlier in the year. Although the reproductive performance of Brown Thornbills improves considerably with age 1 found no evidence that performance improved as a result of repeated breeding attempts with the same partner.