999 resultados para reproductive


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Some aspects of the reproductive biology of the polychaete Gorgoniapolynoe caeciliae have been described for the first time. Gorgoniapolynoe caeciliae is a deep-sea commensal species associated with Candidella imbricala, all octocoral that populates the New England Seamount chain. Gorgoniapolynoe caeciliae is a dioccious species with an equal sex ratio and fertile segments throughout most of the adult body. The gonads of both sexes are associated with genital blood vessels emerging from the posterior surface of most intersegmental septa. In the female, oogenesis is intraovarian with oocytes being retained within the ovary until vitellogenesis is completed. The largest female examined contained over 3000 eggs with a maximum diameter of 80-90 mu m. In the male, the testes are repeated in numerous segments and consist of small clusters of spermatogonia, spermatocytes and early spermatids associated with the walls of the genital blood vessels. Early spermatids are shed into the coelom where they complete differentiation into mature ect-aquasperm with a spherical head (4 mu m), a small cap-like acrosome, and a short mid-piece with four mitochondria. Indirect evidence suggests that this species is an annual breeder that releases its gametes into seawater and produces a planktotrophic larva following fertilization. The reproductive biology of G. caeciliae is consistent with that of most other polynoids including many shallow water species suggesting that phylogenetic history strongly shapes its biology.

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Numerous genes expressed in placenta or testis localize to the X-chromosome. Both tissues undergo specialized X-chromosome inactivation (imprinted paternal inactivation in placenta and MSCI in testicular germ cells). When the X-chromosome is duplicated or improperly inactivated, defects in placentation, growth and spermatogenesis are noted, suggesting tight control of X-chromosome gene dosage is important for reproduction. ^ Esx1 is a mouse homeobox gene on the X-chromosome with expression limited to extraembryonic tissues and testicular germ cells. Here, we examine the effects of increased and decreased Esx1 dosage on placental and testicular development, the role of genetic background on Esx1 function and characterize the human orthologue of Esx1. ^ Previously, by targeted deletion, Esx1 was shown to be an X-chromosome imprinted regulator of placental development and fetal growth. We show C57Bl6-congenic Esx1 mutants display a more severe phenotype with decreased viability and that the 129 genetic background contains dominant modifier genes that enhance Esx1 mutant survival. ^ Varying Esx1 dosage impacts testicular germ cell development. Esx1 hemizygous null mice are fertile, but we show their testes are two-thirds normal size. To examine the effect of increased Esx1 dosage, Esx1 BAC transgenic mice were generated. Increased Esx1 dosage results in dramatic deficits in testicular germ cell development, leading to sterility and testes one-fourth normal size. We show germ cell loss occurs through apoptosis, begins between postnatal day 6 and 10, and that no spermatocytes complete meiosis. Interestingly, increased Esx1 dosage in testes mimics germ cell loss seen in Klinefelter's (XXY) mice and humans and may represent a molecular mechanism for the infertility characteristic of this syndrome. ^ Esx1 dosage impacts reproductive fitness when maternally transmitted. Three transgenic founder females were unable to transmit the transgene to live offspring, but did produce transgenic pups at earlier stages. Additionally, one line of Esx1 BAC transgenic mice demonstrated decreased embryo size and fitness when the transgene is inherited compared to wild type littermates. ^ It is possible that Esx1 plays a role in human disorders of pregnancy, growth and spermatogenesis. Therefore, we cloned and characterized ESX1L (human Esx1), and show it is expressed in human testis and placenta. ^

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Regardless of genetic sex, amniotes develop two sets of genital ducts, the Wolffian and Müllerian ducts. Normal sexual development requires the differentiation of one duct and the regression of the other. I show that cells in the rostral most region of the coelomic epithelium (CE) are specified to a Müllerian duct fate beginning at Tail Somite Stage 19 (TS19). The Müllerian duct (MD) invaginates from the CE where it extends caudally to and reaches the Wolffian duct (WD) by TS22. Upon contact, the MD elongates to the urogenital sinus separating the WD from the CE and its formation is complete by TS34. During its elongation, the MD is associated with and dependent upon the WD and I have identified the mechanism for MD elongation. Using the Rosa26 reporter to fate map the WD, I show that the WD does not contribute cells to the MD. Using an in vitro recombinant explant culture assay I show that the entire length of the MD is derived from the CE. Furthermore, I analyzed cell proliferation and developed an in vitro assay to show that a small population of cells at the caudal tip proliferates, laying the foundation for the formation of the MD. I also show that during its formation, the MD has a distinctive mesoepithelial character. The MD in males regresses under the influence of Anti-Müllerian Hormone (AMH). Through tissue-specific gene inactivation I have identified that Acvr1 and Bmpr1a and Smad1, Smad5 and Smad8 function redundantly in transducing the AMH signal. In females the MD differentiates into an epithelial tube and eventually the female reproductive tract. However, the exact tissue into which the MD differentiates has not been determined. I therefore generated a MD specific Cre allele that will allow for the fate mapping of the MD in both females males. The MD utilizes a unique form of tubulogenesis during development and to my knowledge is the only tubule that relies upon a signal from and the presence of another distinct epithelial tube for its formation.^

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Purpose. The purpose of this study was to identify the health needs and barriers that young men face in accessing health care and family planning services and to identify what health centers can do to attract young men to the clinic. A focus group format was used to elicit ideas from participants. ^ Methods. Forty-eight young men participated in nine focus groups. The young men were asked about the health issues they have, the barriers they face in accessing reproductive health care, and what clinics can do to attract young men to the clinic. Thematic analysis principles were used to identify the main themes that emerged in the focus groups. ^ Results. Sexually transmitted infections (STIs), mental health problems, and drug use were the major health issues that were mentioned in the majority of the focus groups. The main barriers discussed in the focus groups were attitudinal factors such as young men thinking it is unmanly to seek help, emotional factors such as young men not seeking help because of their ego or pride, and institutional factors such as the location of the clinic. The main suggestions for improvements in the health clinic included decreasing waiting times, emphasizing the fact that the clinics are free for males, having more female nurses, and encouraging clinic staff to treat the young men with respect. Young men suggested advertising and promoting the clinic in schools, in the community, and through the media. Focus group participants also provided their input about the design and format of the clinic flyer. ^ Conclusions. Many studies focus on the reproductive health care needs of adolescent and young females. This study has helped to show that young men also have health care needs and face barriers to accessing reproductive health care services.^

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This research examined the relation between prenatal exposure to diethylstilbestrol (DES) and subsequent reproductive performance in females. Although previous studies have agreed that unfavorable pregnancy outcomes (spontaneous abortions, stillbirths, ectopic pregnancies, and premature births) occur with greater frequency in the exposed as compared to unexposed women, the role of exposure to DES in-utero on subsequent fertility (pregnancy achievement) remains controversial. Also, the possibility that the reproductive dysfunction reported in exposed women might be due to familial predisposition to reproductive dysfunction rather than to DES exposure has not been examined heretofore.^ The purposes of the research were to: (1) measure the overall differences in rates of live births between exposed and unexposed women; (2) determine if infertility or early unrecognized spontaneous miscarriages (as opposed to recognized fetal death) contributes to poor reproductive performance in the exposed; and (3) determine if constitutional predisposition contributes to poor reproductive performance in exposed daughters.^ The study population comprised those participants in the National Cooperative Diethylstilbestrol Adenosis (DESAD) Project who were identified through review of prenatal records. Birth interval curves (survival analyses) were used to compare the reproductive performance of exposed daughters and unexposed women. Birth interval curves were also constructed for unexposed siblings (of exposed participants) and unexposed nonsiblings to determine the role of constitutional predisposition in the reproductive performance of exposed daughters.^ The DES-daughters, as compared to unexposed women, were found to be at a reproductive disadvantage when the overall differences in rates of live births were compared.^ When the differences in rates of live births due specifically to infertility or early unrecognized spontaneous miscarriages (as opposed to recognized fetal death) were examined, the exposed maintained the reproductive disadvantage. This analysis was suggestive but not statistically significant for the first-birth-interval and was neither suggestive nor significant in the second-birth-interval. (Abstract shortened with permission of author.) ^

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Sexual/reproductive/health and rights are crucial public health concerns that have been specifically integrated into the Millennium Development Goals to be accomplished by 2015. These issues are related to several health outcomes, including HIV/AIDS and gender-based violence (GBV) among women. The Middle East and North Africa (MENA) region comprises Algeria, Bahrain, Egypt, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Qatar, Saudi Arabia, Syria, Tunisia, United Arab Emirates (UAE), West Bank and Gaza (WBG), and Yemen. This region is primarily Arabic speaking (except for Israel and Iran), and primarily Muslim (except for Israel). Some traditional and cultural views and practices in this region engender gender inequalities, which manifest themselves in the economic, political and social spheres. HIV and gender-based violence in the region may be interlinked with gender inequalities which breed justification for partner violence and honour killings, and increase the chance that HIV will transform into an epidemic in the region if not addressed. A feminist framework, focused on economic, political and social empowerment for women would be useful to consider applying to sexual/reproductive health in the region.^