The contribution of recombinant DNA techniques to reproductive biology.
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Animals↗
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Illustration preparation and reproduction techniques-the publishers' needs.
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Medical Illustration↗
Early embryonic development and evaluation of equine embryo viability.
Tremendous progress has been made in the development of assisted reproductive techniques that may enhance the reproductive efficiency of the horse. However, techniques that involve the manipulation of oocytes and/or embryos may themselves be detrimental to embryo viability and subsequent development. Therefore, an objective method of assessing viability of embryos before and/or after oocyte/embryo manipulation is desirable. At this time, morphologic evaluation is the most widely used method of determining the viability of equine embryos. Although morphologic assessment of embryo quality will not always accurately predict the survival of individual embryos, it is very useful for predicting the survival of groups of embryos. Other tests that have been used to evaluate equine embryo viability include (1) development during culture in vitro; (2) quantitating metabolism of the fluorescent substrate fluorescein diacetate; (3) quantitating uptake of the fluorescent stain DAPI; and (4) quantitating embryo metabolism. Although these tests offer potential advantages over morphologic assessment alone, their current limitations have prevented their routine use for embryo evaluation. It is likely that as improvements are made in these evaluation methods, they may offer advantages for use alone or in combination to more accurately assess the viability of equine embryos.
Animals↗
Current and future issues in assisted reproduction.
The last quarter of the twentieth century has given rise to reproductive technologies and arrangements that in the earlier part of the century could only be dreamed of by the authors of science fiction. We stand in the middle of this reproductive revolution, trying to cope with the developments that have already occurred but with an uneasy sense that the future may be even more complicated ethically than the past and the present. In this brief essay, I will survey recent ethical and public-policy discussions of two reproductive techniques (assisted insemination and in vitro fertilization) and one reproductive arrangement (surrogate motherhood). After distinguishing three phases in the normative debate, I will briefly comment on some of the characteristics of, and continuing ambiguities in, the ethical debate of the past 25 years. At the conclusion of the essay, I will attempt to anticipate three future issues in ethics and reproduction.
Advisory Committees↗
Male infertility in spinal cord trauma.
Every year there are 10 thousand new cases of patients victimized by spinal cord trauma (SCT) in the United States and it is estimated that there are 7 thousand new cases in Brazil. Eighty percent of patients are fertile males. Infertility in this patient group is due to 3 main factors resulting from spinal cord lesions: erectile dysfunction, ejaculatory disorder and low sperm counts. Erectile dysfunction has been successfully treated with oral and injectable medications, use of vacuum devices and penile prosthesis implants. The technological improvement in penile vibratory stimulation devices (PVS) and rectal probe electro-ejaculation (RPE) has made such procedures safer and accessible to patients with ejaculatory dysfunction. Despite the normal number of spermatozoa found in semen of spinal cord-injured patients, their motility is abnormal. This change does not seem to be related to changes in scrotal thermal regulation, frequency of ejaculation or duration of spinal cord damage but to factors related to the seminal plasma. Despite the poor seminal quality, increasingly more men with SCT have become fathers through techniques ranging from simple homologous insemination to sophisticated assisted reproduction techniques such as intracytoplasmic sperm injection (ICSI).
Erectile Dysfunction↗
The European study of assisted reproduction families: a comparison of family functioning and child development between Eastern and Western Europe.
Developments in reproductive technology over the past 20 years have given infertile couples new opportunities to have children. Although assisted reproduction does not appear to lead to negative consequences with respect to parent-child relationships or the socioemotional development of the child, the outcome for children and their parents may well differ according to the social and cultural environment. The aim of the present study was to compare family functioning and the social and emotional development of children in families created as a result of assisted reproductive techniques in Western Europe with assisted reproduction families in an Eastern European country (Bulgaria) where there is a history of specific pronatalist interventions. The findings indicate greater difficulties in parental adjustment and child behavior in assisted conception families in Eastern Europe. In addition, Eastern European parents were more uncertain than Western European parents about whether they would tell the child, and Eastern European parents were much more secretive with respect to telling others. Thus the outcomes of assisted reproduction for family functioning and child development appear to be independent, to some extent at least, on the social context in which these techniques are carried out.
Adaptation, Psychological↗
Clinical practice of embryo transfer.
In this review, several embryo transfer methods are considered, together with factors involved in achieving an effective transfer. The approach most used is transcervical intrauterine transfer. This is described in detail, together with the many variables influencing success, e.g. technical ability and training of personnel, catheter choice, value of a previous 'dummy transfer' and the need to minimize trauma during transfer and so prevent damage to the uterine lining, bleeding and uterine contractions. These factors can each negatively impact on pregnancy rates. Emphasis is put on quality, developmental stage and number of embryos to be transferred to limit multiple pregnancies and their unwanted side-effects. Culture to blastocyst stages and single embryo transfer when optimal quality embryos are available are discussed as means of avoiding multiple pregnancies. Reference is made to embryo cryopreservation and fertility following frozen embryo transfer. Other techniques, such as ultrasound-controlled transcervical intrauterine transfer, and ultrasound-controlled transmyometrial transfer, are reviewed. More invasive procedures, generically grouped as surgical embryo transfer, including gamete intra-Fallopian transfer (GIFT), zygote intra-Fallopian transfer (ZIFT), pronuclear stage transfer and embryo intra-Fallopian transfer (EIFT), are also described. These techniques had a place in IVF when the need to apply assisted reproductive techniques exceeded the capacity of most laboratories, but not today thanks to refined laboratory technology and improved understanding of implantation. Alternative assisted reproductive technologies, such as direct intra-follicular insemination (DIFI), Fallopian spermatic perfusion (FSP), peritoneal oocyte stage and sperm transfer and intra-vaginal culture (IVC), are mentioned briefly.
Cryopreservation↗
Perspectives: the possible influence of assisted reproductive technologies on transgenerational reproductive effects of environmental endocrine disruptors.
Demasculinization by environmental endocrine-disrupting chemicals (EDCs) is observed in many animal species but less evident in humans. Rodent studies with gestational exposure to either the fungicide vinclozolin or the insecticide methoxychlor demonstrate impaired male fertility with abnormal DNA methylation patterns in spermatozoa. Once established, these epigenetic changes may be permanent and thus paternally passed to subsequent generations. Conclusive evidence of a similar phenomenon in humans has not been established, but several observations bring up the possibility. Some, but not all, studies show an increase in male genital abnormalities after prenatal EDC exposure. Other studies demonstrate sperm abnormalities in males with EDC contact, although it is unclear as to whether this is due to prenatal or postnatal exposure. Although not examined in males with EDC exposure, one study shows gamete DNA methylation abnormalities in males with severe oligospermia. A subsequent study failed to corroborate these findings. The use of assisted reproductive techniques including intracytoplasmic sperm injection has removed natural selection barriers thus enabling reproduction in males that would otherwise be sterile. This review explores the hypothesis that prenatal EDC exposure results in transgenerational male reproductive abnormalities propagated by the use of assisted reproductive technologies.
Animals↗
Male factor infertility and assisted reproductive technologies.
Male infertility has many facets that need to be evaluated in an initial screening. Once these are known, recommendations become clearer for aggressively pursuing assisted reproductive techniques. Progress has been made in defining more clearly the severe male factor: concentration less than 5 x 10(6) sperm/mL, motility less than 10%, morphology less than 4% normal forms (by strict criteria), and recovered swim-up sperm less than 1.5 x 10(6). Sperm preparation techniques may be improved by use of Percoll separation medium, and morphology may be used in prediction of cleavage rate in in vitro fertilization. Hopefully, these techniques will lead to more specific guidelines for successful use of assisted reproductive technology in male factor patients.
Female↗
Improvement of sperm motility by the addition of progesterone to the Percoll medium during sperm purification.
The Percoll centrifugation technique is widely used to select the most motile spermatozoa in connection with assisted reproduction techniques (ART). Progesterone is known to enhance the motility of spermatozoa in vivo and in vitro. This study evaluates whether the motility of spermatozoa can be enhanced by the presence of progesterone simultaneously with purification using a routine Percoll centrifugation technique. Motility is measured by computer-assisted sperm analysis. The 100% Percoll medium contained a progesterone concentration of 2 micrograms/ml, which is in the range of that found in pre-ovulatory follicular fluid and peritoneal fluid around ovulation. With a two-layer purification procedure (55/80% Percoll medium), exposure of the progesterone in the Percoll medium for only 25 min caused a highly significant improvement of motility in the spermatozoa isolated from the semen samples of 14 healthy men. It is concluded that the addition of progesterone to the Percoll purification medium can further enhance sperm motility without the need for a change in the routinely used semen purification technique in most assisted reproduction programmes.
Cell Separation↗
Italy enacts new law on medically assisted reproduction.
In 2004, the Italian Parliament enacted a law regulating medically assisted reproduction. Although the law recognizes as legal certain assisted reproduction techniques, several other procedures are implicitly or expressly banned: oocyte and sperm donation, using embryos for the scientific research purposes and reproductive cloning. In this article, I outline the new legal framework, pointing out some of the shortcomings of its provisions, such as the failure to define what an 'embryo' is, the contradictions between this law and the law on abortion, the opportunity for Italian couples to circumvent some of the prohibitions by resorting to 'reproductive tourism', and the central role that physicians play in the new legal framework.
Cryopreservation↗
Features associated with reproductive ageing in female rhesus monkeys.
BACKGROUND: The specific aims were to determine the effects of maternal age on the meiotic and developmental competence of oocytes and incidence of chromosomal anomalies in oocytes from a population of fertile rhesus monkeys. METHODS: Monkeys were divided into two age groups (4-15 and 16-26 years of age) and underwent ovarian stimulation for collection of oocytes. RESULTS: In the older, compared with younger, monkeys, serum basal concentrations of FSH were elevated (P < 0.05), peak concentrations of estradiol during a stimulation cycle were diminished (P < 0.05), and mean numbers of oocytes retrieved following ovarian stimulation were markedly (P < 0.05) reduced. There were no significant maternal age-related impairments in oocyte maturation, fertilization or blastocyst development. Both abnormal numbers of whole chromosomes, as well as free chromatids, were detected in a limited number of rhesus oocytes. CONCLUSIONS: Similarities between female rhesus monkeys and women in several features associated with reproductive ageing, in conjunction with our ability to perform IVF and other assisted reproductive techniques in monkeys, demonstrate the suitability of these animals for studies on human reproductive ageing and maternal age-related infertility. Although maternal age-related impairments in oocytes were not evident prior to implantation, further studies may reveal more subtle impairments, manifested during post-implantation development.
Aging↗
[Oocyte donation in France and national balance sheet (GEDO). Different European approaches].
Oocyte donation (OD), a technique successfully used in Assisted reproductive techniques (ART), has been effective for 20 years as the palliative treatment of certain exocrine ovarian failures. Its indications have also been extended to cover some genetic diseases and documented occult ovarian insufficiency. In France, after an extensive judicial and ethical deliberation, OD was deemed legal and its practice was proscribed in the Bioethics Laws 94-653 and 94-654 of 29 July 1994. Its essential underlying principles are: voluntary, free, anonymous and confidential OD; according to a French decree to meet safety concerns, OD-derived embryos must be quarantined for six months. In vitro fertilization (IVF) programs using donated oocytes are conducted in authorized centers under the responsibility of physicians authorized to retrieve and manipulate donated oocytes. The managers of these programs are the system's keystone, as their role includes, among other, the verification of indications, legal documents, public health safety, anonymous pairing of donor and recipient, and the collection of outcome data. At present, depending of the year, French programs have achieved 17-22% clinical pregnancy rates from transferred OD-derived frozen-thawed embryos, and follow-up studies reported excellent results concerning family relationships, and the physical and psychological development of the children. However, difficulties encountered in the daily practice of OD have led concerned physicians to form the Study group for OD (GEDO) to explore different topics with the aim of improving the overall management of this form of ART. We discussed these points herein, in comparison with the approaches of other European countries.
Adult↗
[Gynecologic surgery evolution during the 50 years of professional career in surgery].
This is a retrospective analysis of how gynecological surgery has changed over the last 50 years; these practices have been modified from mutilative and extirpative to conservative and with the least invasion possible. The major breakthroughs-apart from changes in pathology-have been those with use of microsurgery techniques, endoscopic surgery, and assisted reproductive techniques; this highlights the fact that each day surgeon gynecologists are better prepared. Also, there has occurred the notable evolution of methods of detection and diagnosis such as laboratory test, MRI, ultrasound, CT, etc. as well as anesthetic procedures. We describe the most notable changes of gynecological surgery techniques with different examples and figures. Surgical obstetric procedures will be shown in another communication.
Female↗
[Assisted fertilization--where are we now and where are we going?].
The authors review the development of assisted reproduction, and describe the present status. The efficacy of in vitro fertilization is compared with the results of tubal surgery. A comparison is also made of the efficacy of different assisted reproductive techniques. Future aspects of assisted reproduction are discussed, with particular emphasis on the need for better understanding of the implantation process. This may reduce the need for transfer of multiple embryos, thereby decreasing risk of multiple pregnancies.
Female↗
[Human oocyte freezing in Spain: comment on the Real Decree 120/2003].
This work analyzes some scientific, ethic and legal aspects about the freezing of human ovocites in Spain. Inside the context of the Law 35/1998 of Assisted Reproduction Techniques, it is analyzed the Royal Decree 120/2003 which regulates the authorization of controlled experiences with reproductive aims. These experiences investigate the fecundation of ovocites or ovaric tissue previously frozen. It is also studied the inform made through parliament by the General Court of Judicial Power and it is also valued the importance of the terms "experience", "investigation" and "project" used in the legal text.
Cryopreservation↗
Presence of thyroid antibodies in early reproductive failure: biochemical versus clinical pregnancies.
OBJECTIVE: To evaluate the clinical usefulness of thyroid antibodies in determining early pregnancy outcome. SETTING: University-based facility at the Center for Reproductive Health, University of California, Irvine. PATIENTS: Four hundred eighty-seven infertile patients that successfully conceived with assisted reproductive techniques from January 1991 to December 1992. INTERVENTIONS: An enzyme immunoassay for semiquantification of thyroglobulin (TG) and thyroid peroxidase antibodies used to determine antibody status from stored serum of these patients. MAIN OUTCOME MEASURE: Thyroid antibody status in early pregnancy. RESULTS: Of the 487 patients studied, there were 106 women who were antibody positive for anti-TG, antithyroid peroxidase, or both, and 381 who were negative. The overall incidence of positivity was 22%. In the antibody-positive group there was a 32% clinical miscarriage rate in comparison to 16% in the antibody-negative group. This did reach statistical significance. There was no significant difference between the two groups in the incidence of biochemical or ectopic pregnancies. There also was no significant difference between the groups in age, gravidity, or number of prior pregnancy losses. CONCLUSION: In our patient population, thyroid antibodies proved to be a useful marker for identifying women at risk for clinical miscarriage but they appear not to have an association with biochemical pregnancies.
Abortion, Spontaneous↗
To add or not to add LH: comments on a recent commentary.
From a period of time when LH activity supplementation in stimulation protocols for assisted reproductive technology was questioned, recent scientific evidence seems to prove a role of LH activity in optimizing the clinical results of certain subgroups. Until now, apart from the hypogonadotrophic hypogonadal patient, two subgroups of patients have attracted attention: patients over 35 years of age, and normogonadotrophic patients with an initial low response to recombinant FSH (rFSH). However, in a recent paper, another subgroup of patients has been identified: normogonadotrophic patients with high endogenous LH levels (>1.99 IU/l) on day 8 of stimulation after a long GnRH agonist down-regulation. By adding recombinant LH (rLH) from day 8 to the stimulation protocol, this subgroup of patients achieved good implantation rates, similar to those of patients with lower LH levels. Interestingly, the dynamics of the endogenous LH levels during down-regulation in this group of patients differed from those of patients with lower LH levels. The immunoreactivity of the LH molecule does not necessarily reflect the bioactivity, which might explain the beneficial effect of LH activity supplementation in patients with high endogenous LH levels after down-regulation. Future studies should be focused on subgroups to further explore the effect of LH activity supplementation in assisted reproduction techniques.
Adult↗