Contraception, fertilite, sexualite (1992)最新文献

Background: Couples where the male partner is HIV-infected but the female partner is not often express a desire for children. Assisted reproduction techniques (ART) with sperm "wash" can reduce the risk of acquisition of infection for the woman. The information about the characteristics of such couples coming to these clinics for advice and support is scant.

Objective: To describe the characteristics of a cohort of HIV-discordant couples seeking reproductive assistance in a referral clinic in Barcelona, Spain.

Methods: Demographic, social and HIV related information were collected prospectively according to a standard protocol. Blood tests, a full evaluation for STDs and sperm analysis were performed.

Results: Between April 1994 and February 1999, 140 couples contacted the clinic for reproductive advice, 100 couples were fully assessed and were offered reproductive assistance. The vast majority were white, with a history of injecting drug use. Nearly half of the men had been diagnosed during their present relationship. STDs were uncommon and abnormalities among sperm analysis were frequent.

Conclusion: An increasing number of HIIV infected individuals desire to have children. With the introduction of HAART and the safety of sperm wash in such cases, the need to have children is more frequently expressed. These couples are in general healthy and accept to be included in an ART program.

Sex determination relies on the translation of chromosomal sex established at fertilisation into gonadal sex (testis or ovary), and later into somatic sex (male or female) under the control of gonadal hormone secretions. The aim of the current review will be to highlight our knowledge of the key events which, in the presence of a Y chromosome, induce the organisation of the developing epithelial cells located inside the genital ridges into testicular cords. Many groups have tried to define the molecules relevant to this process, with a double goal: unravelling a molecular pathway which leads to cell fate decision (Sertoli cell in this particular case) during development; improving the establishment of a diagnosis and subsequent medical management in cases where chromosomal, gonadal and then somatic sexes are discordant. Recent progress made in this area will be depicted, with the introduction of several pieces to this developmental jigsaw puzzle.

Maturation of human oocytes has 3 aspects: nuclear maturation leading to the extrusion of the 1st polar body, membranar maturation essential for the fixation of spermatozoa to the zona pellucida and penetration into the oocyte and cytoplasmic maturation which allows protein synthesis required for normal fertilisation and embryo development. In vitro maturation (IVM) of human oocytes may be appropriate in 5 different situations: for PCOs patients (natural cycle), in normoovulatory patients (natural cycles), for oocytes not exposed to hCG (stimulated cycle), for immature oocytes recovered in the course of an ICSI protocol (stimulated cycle) and after freezing-thawing of immature oocytes. Data from the literature show that in vitro maturation of human oocytes together with ICSI can lead to normal fertilisation, embryo development, pregnancies and the delivery of healthy children. However, the overall efficiency is still very low, indicating that embryo viability is compromised. The incidence of chromosome abnormalities in mature oocytes obtained after IVM is similar to that of oocytes recovered after in vivo maturation and therefore does not seem to be the reason of the failures. Conversely, protein synthesis abnormalities and abnormal calcium signalling might explain the poor viability of the embryos. The key factor seems to be cytoplasmic maturation not yet fully understood in the human.

Human embryonic cells obtained through somatic cloning would allow selfgrafting for therapeutical purposes. Data available from animal research indicate that this issue should be considered with great care.

During the year 1998, the French Federation of CECOS recorded the results of the 23 CECOS centers and IFRAERES in Toulouse. 1,573 first demands of procreation with sperm donors were registed (versus 1,620 in 1997). From 9,339 cycles (AID or IVFD), 1351 pregnancies were obtained, scoring the identical amount in terms of pregnancies as in 1997 but with less 9% in terms of cycles. Ovulation monitoring and IVFD are more and more used. The analysis of the 1,169 deliveries of the 1997 pregnancies shows a malformation rate of 1.8%. 658 male volunteers came forward as semen donors (51% more than in 1997). In gamete autocryopreservation, the number of semen preservation is globaly increasing (16% more than in 1997), mainly due to the capacity of a better reutilisation with ICSI. At the end of 1998, 15 Centres was looking after 21,222 cryopreserved embryos, 25% in the aim of a near future use.

In children and young women, antimitotic chemotherapy and radiotherapy can provoke premature ovarian failure, as well as chromosomal or genic mutations potentially responsible of pregnancy wastage, congenital malformations or genetic diseases in the progeny. After an abdominal radiotherapy, the long term sequelae of uterine irradiation can induce pregnancy wastage, prematurity or low birth-weight. Irreversible ovarian damages are mainly due to alkylating agents and abdominal radiotherapy. The gradual depletion of the follicular pool accounts for the apparent increasing ovarian sensitivity: in women over 40, almost any therapy can be responsible of an immediate menopause, while in younger patients retaining a normal ovarian function at the end of a treatment including alkylating agents or an abdominal radiotherapy, a premature ovarian failure will occur several years later.

Oocyte maturation represents the final step of a long differentiation process that allows this very special cell to fully express its reproductive task. During maturation the oocyte nucleus, blocked at the late prophase of meiosis from the end of foetal life, resumes meiosis and progress to the metaphase II stage. Beyond these nuclear aspects, oocyte maturation also involves cytoplasmic modifications including well known morphological progression as well as poorly understood biochemical changes that are determinant for successful fertilisation and early embryo development. In physiological conditions, maturation occurs in the preovulatory follicle after the ovulatory surge of gonadotropins, in a complex and changing environment. This complexity leaded to the formulation of the first in vitro maturation systems involving tissue culture media supplemented with biological fluids. A more precise study of the effect of individual medium components allowed the design of more simple maturation conditions providing more reproducible results with less sanitary risks. Amongst maturation activating factors, the epidermal growth factor (EGF) seems to play a key function in several species. Other factors such as hormones, ovarian peptides (inhibin, activin) and other growth factors may also be involved but the interplay between these factors remains to be clearly established. Improvement of in vitro maturation techniques allowed to evaluate the importance of oocyte intrafollicular differentiation before maturation on the resulting developmental competence. The increased knowledge of the regulation of intrafollicular meiotic arrest now allow the design of a prematuration step to allow oocytes from smaller follicles to complete their differentiation in vitro. This improvement will allow a larger use of the huge reproductive potential stored in the ovary.

Fertility and results of infertility therapies are submitted to amajor drop in relation with the age of the female patient and her so-called ovarian reserve. Although there is no clear definition of what is exactly the ovarian reserve, the consequence of its decline is a greater difficulty to produce ovocytes with a capacity of becoming living embryos after fertilization. Several tests have been developed to assess the ovarian reserve in order to evaluate the prognosis of spontaneous fertility, the results of infertility therapy and assisted procreation techniques, and to make necessary technical adaptations. Basal determinations of FSH, estradiol and inhibin B at day 3 of the cycle an all reflect the ovarian potential, but only FSH reflects a decline infecundability reliable enough to be used as a screening test. Challenge tests such as the clomiphene citrate, the exogenous FSH or the GnRH challenge tests have the purpose to reveal an exaggerated liberation of FSH or an insufficient secretion of estradiol after stimulation. None of these tests have demonstrated a better sensibility together with a higher specificity and they should be considered as evaluating tools in specific cases only. In conclusion, assessing the ovarian reserve has become a clinical necessity in the following situations: ovulation defect, unexplained infertility, before undergoing ovarian stimulation for assisted procreation, in particular in women above the age of 35. This assessment can be made by determining the basal FSH level on day 3 of a cycle and should be renewed every year.