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Y Englert

Publications and source records attributed to Y Englert.

At least 19 recordsLinked to original sources
PubMed2005

Impact of various endocrine and paracrine factors on in vitro culture of preantral follicles in rodents.

Folliculogenesis is a complex process regulated by various paracrine and autocrine factors. In vitro growth systems of primordial and preantral follicles have been developed for future use of immature oocytes, as sources of fertilizable oocytes and for studying follicular growth and oocyte maturation mechanisms. Rodents were often chosen for in vitro follicular culture research and a lot of factors implicated in folliculogenesis have been identified using this model. To date, the mouse is the only species in which the whole process of follicular growth, oocyte maturation, fertilization and embryo transfer into recipient females was successfully performed. However, the efficiency of in vitro culture systems must still be considerably improved. Within the follicle, numerous events affect cell proliferation and the acquisition of oocyte developmental competency in vitro, including interactions between the follicular cells and the oocyte, and the composition of the culture medium. Effects of the acting factors depend on the stage of follicle development, the culture system used and the species. This paper reviews the action of endocrine, paracrine factors and other components of culture medium on in vitro growth of preantral follicles in rodents.

Animals↗
PubMed2004

Acute eosinophilic pneumonia associated with intramuscular administration of progesterone as luteal phase support after IVF: case report.

We report two cases of acute eosinophilic pneumonia induced by i.m. administration of progesterone used as luteal phase support after IVF. For both patients, the symptoms began 3 weeks after the first injection of progesterone. Both patients were in respiratory distress, and one of them required ventilatory assistance for a week, with 5 days in the intensive care unit. Symptoms improved as the i.m. form was shifted to a vaginal form of progesterone together with the administration of corticosteroids. Sesame oil (used as excipient) and benzyl alcohol (used as preservative) could both be incriminated in the development of the hypersensitivity reaction. The need for luteal phase support is clearly established in IVF cycles with GnRH agonist protocols, and progesterone is the generally recommended compound. However, there is no definitive consensus regarding the optimal route of administration of progesterone. These two cases of acute drug-induced disease show that the use of i.m. progesterone can be associated with a severe morbidity in otherwise healthy young patients. This is an additional argument to advocate the use of vaginal progesterone as luteal support in IVF.

Acute Disease↗
PubMed2004

Effect of insulin-like growth factor-I during preantral follicular culture on steroidogenesis, in vitro oocyte maturation, and embryo development in mice.

Insulin-like growth factor-I (IGF-I) is involved in the regulation of ovarian follicular development and has been shown to potentiate the FSH responsiveness of granulosa cells from preantral follicles. The aim of the present study was to investigate the effect of IGF-I during preantral follicular culture on steroidogenesis, subsequent oocyte maturation, fertilization, and embryo development in mice. Preantral follicles were isolated mechanically and cultured for 12 days in a simplified culture medium supplemented with 1% fetal calf serum, recombinant human FSH, transferrin, and selenium. In these conditions, follicles were able to grow and produce oocytes that could be matured and fertilized. The first experiment analyzed the effect of different concentrations of IGF-I (0, 10, 50, or 100 ng/ml) added to the culture medium on the follicular survival, steroidogenesis, and the oocyte maturation process. The presence of IGF-I during follicular growth increased the secretion of estradiol but had no effect on the subsequent oocyte survival and maturation rates. In the second experiment, IGF-I (0 or 50 ng/ml) was added to the culture medium during follicular growth, oocyte maturation, or both, and subsequent oocyte fertilization and embryo development rates were evaluated. Oocyte fertilization rates were comparable in the presence or absence of IGF-I. However, the blastocyst development rate was enhanced after follicular culture in the presence of IGF-I. Moreover, the total cell number of the blastocysts observed after differential labeling staining was also higher when follicles were cultured or matured in the presence of IGF-I.

Animals↗
PubMed2004

[Ten years follow-up of medically assisted procreation in Belgium].

Since 1989, the data concerning medically assisted procreation (MAP) in Belgium have been registered through the BELRAP association (Belgian Register for Assisted Procreation). In 1999, the national College of Physicians in Reproductive Medicine has been installed and given the mission to carry out the quality controls and the registration of MAP activities in our country. In 2001, a new on line system of registration of all treatment cycles was started, the basic structure of the corresponding data base having undergone a series of changes along the years. Although the number of MAP trials has considerably increased in our country, mainly because of the introduction of new techniques such as intracytoplasmic injection of sperm (ICSI), the success rate per trial has remained almost unchanged, becoming stabilized around 18.8% of ongoing pregnancies per initiated cycle. The main modification that occurred during the analyzed period has been the reduction of the number of embryos transferred at each trial, being first reduced from 3 to 2 to evolve more recently towards the replacement of only one embryo per trial. Multiple pregnancies are indeed the chief complication of MAP and in order to avoid it Belgian centers have been among the first to reduce drastically the number of transferred embryos. In 2003, legal rules were enacted, fixing the number of replacable embryos in accordance to the patient's age and to the rank of trial, while also solving the problem of the long-awaited reimbursement of MAP by our national social security system.

Belgium↗
PubMed2002

[What kind of support do couples expect when undergoing IVF treatment? Study and perspectives].

OBJECTIVES: To assess the management of the supportive aspects of treatment for couples having attempted an in vitro fertilization treatment. MATERIAL AND METHODS: Three groups of couples were contacted by questionnaire (successful treatment, unsuccessful treatment treatment, outcome still unknown). RESULTS: 48% considered it necessary to offer psychological support after the diagnosis. 80% considered it difficult to have a thorough representation of the physical aspects of an In Vitro Fertilization treatment but mostly they were surprised by their lack of an accurate emotional representation. All couples expected an availability and receptiveness from the infertility team but the unsuccessful treatment group was less satisfied and felt significantly (P < 0.001) less well supported. The most difficult moments mentioned were the numerous moments of waiting and the announcement of the final result. Emotional support was regularly provided by the nurses but 20% wanted psychological counselling. Two thirds of all couples considered that a psychological follow-up should be proposed to couples for whom the treatment remain unsuccessful. CONCLUSIONS: Results show the need for better emotional preparation of couples. As for the emotional support during treatment, the need for psychological counselling appears after the diagnosis of infertility as well as a constant demand of availability and empathy on behalf of the team. Post-treatment counselling may be particularly important also. Failure as well as lack of support at that time seemed to colour the way couples regard the whole support provided during treatments.

Adaptation, Psychological↗
PubMed2002

[Turner's syndrome and oocyte donation].

This paper reviews literature about oocyte donation for patients with Turner's syndrome and reports the experience of our center. Before contemplating pregnancy, it is essential to perform a careful evaluation of the cardiovascular system, the renal system, the thyroid status and the glucose tolerance. Different studies have reported a suboptimal response of the endometrium of women with Turner's syndrome to oestrogen therapy, and suggested that higher doses of estrogens may be necessary to achieve appropriate endometrial preparation. Pregnancy rate per transfer following oocyte donation is around 30% for patients with Turner's syndrome, comparable to the one observed for patients with other conditions requiring oocyte donation. Miscarriage rate is however higher (40-50%) after oocyte donation in Turner's syndrome, and could be related to the presence of a hypoplastic uterus along with hypovascularization. During pregnancy, cardiovascular complications are potentially the most severe, such as the exacerbation of a preexisting hypertension and the dissection of aortic aneurysms. There is a high rate of Caesarean section among Turner's syndrome patients, the main reason being fetopelvic disproportion. Regarding the increased obstetrical risks in Turner's syndrome patients, the selective transfer of one embryo should ideally be performed in order to avoid additional risks associated with multiple pregnancies. In our center, 9 patients with a Turner's syndrome had 15 cycles of oocyte donation. Five pregnancies were obtained among which three were evolutive. The outcome of oocyte donation cycles were comparable for patients with a Turner's syndrome and for patients with other indications of oocyte donation.

Abortion, Spontaneous↗
PubMed2002

Effect of preantral follicle isolation technique on in-vitro follicular growth, oocyte maturation and embryo development in mice.

BACKGROUND: The use of mechanical and enzymatic techniques to isolate preantral follicles before in-vitro culture has been previously described. The aim of this study was to assess the effect of the isolation procedure of mouse preantral follicles on their subsequent development in vitro. METHODS: Follicles were isolated either mechanically or enzymatically and cultured using an individual non-spherical culture system. Follicular development and steroidogenesis, oocyte in-vitro maturation and embryo development were assessed for both groups. RESULTS: After 12 days of culture, follicles isolated mechanically had a higher survival rate but a lower antral-like cavity formation rate than follicles isolated enzymatically. Enzymatic follicle isolation was associated with a higher production of testosterone and estradiol compared with mechanical isolation. A stronger phosphatase alkaline reaction was observed after enzymatic isolation, suggesting that follicles isolated enzymatically had more theca cells than those isolated mechanically. However, both isolation techniques resulted in similar oocyte maturation and embryo development rates. CONCLUSIONS: Enzymatic follicular isolation did not affect theca cell development. Follicular steroidogenesis was enhanced after enzymatic isolation but the developmental capacity of oocytes was comparable to that obtained after mechanical isolation.

Animals↗
PubMed2002

[Medically assisted reproduction in couples carrying the human immunodeficiency virus].

Today, in developed countries, many HIV-infected people remain in good health thanks to antiviral medication, and a growing number of them want to have children. The benefit of resorting to assisted procreation and the contamination prevention strategies, throughout pregnancy, are summarized as well as the changes in ethical considerations. The balance between the importance of the message of prevention and the benefit for patients of being assisted in their desire for a child, has evolved towards a growing interest for medical intervention in order to avoid the risks of spontaneous conception outside health care structures. We are presenting the medical structure adapted at Erasme hospital and the 38 first requests taken into account by our pluridisciplinary team. This approach, which is coherent from a scientific point of view, respects both the autonomy of people, carrying HIV as well as the essential interest of the child, in being born uninfected, and also has the enormous advantage of allowing access to parenthood without destroying the consistency and coherence of the message of prevention of sexual contamination.

Carrier State↗
PubMed2002

[The gynecology-obstetrics department].

The scientific and clinical activities of the Department of Obstetrics and Gynaecology have involved the three main subdivisions: the gynecological surgery, the obstetrics and fetal medicine, the endocrinology and the reproductive medicine. Minimal invasive surgery including laser assisted laparoscopy or robotic assisted surgery has been particularly developed. Endometriosis, a frequent and sometimes particularly invasive disease, and oncologic surgeries have been developed in collaboration with the digestive surgery department. The department has also contributed to the comprehension and treatment of prenatal pathologies such as premature labor and deliveries or the gestational diabetes. The department has supported the development of techniques to study the fetal well-being in utero: the prenatal echography, the chorionic villous sampling, the amniotic puncture or the cordocentesis for prenatal genetic diagnosis or fetal infectious contaminations, the CMV transmission more specifically. In endocrinology and reproductive medicine, the department has mainly developed the in vitro fertilization techniques. The prolonged embryo culture, the study of preimplantation embryo metabolism, the preimplantation genetic diagnosis and the cryopreservation of ovarian fragments to preserve fertility in women undergoing oncologic treatments represent the more recent developed topics. Finally, the security of viral transmission in assisted procreation and the treatment of these patients with chronic viral diseases (Hepatitis C or HIV) are another domain with important scientific activity.

Belgium↗
PubMed2001

[Medically assisted reproduction and the desire for a child by HIV infected couples: has the time for a change in attitude come?]].

Today, in developed countries, many HIV-infected people remain in good health thanks to antiviral medication. A growing number of them want to have children. Medical possibilities for preventing contamination of the partners of seropositive men through assisted reproduction and of children thanks to antiviral medicines during pregnancy are summarized. These changes result in ethical considerations which lead the authors to question the conventional systematic medical advise against pregnancy and has encouraged them to assist reproduction for a number of these couples. Today, the balance between the importance of the message of prevention and the benefit for patients of being assisted in their desire for a child has tilted towards medical intervention. It would seem legitimate today to intervene in the most favourable situations rather than see these couples take the risk of spontaneous conception outside health care structures. This implies to adapt medical structure (separate laboratory, appropriate procedure, precise protocols). This approach, which is coherent from the scientific point of view, respects both the autonomy of people carrying HIV as well as the essential interest for the child, in "being" born uninfected and also has the enormous advantage of allowing access to parenthood without destroying the consistency of the message of prevention of sexual contamination.

Anti-HIV Agents↗
PubMed2001

Amino acids promote human blastocyst development in vitro.

Supplementation of culture media with amino acids has been shown to benefit preimplantation embryo development in several species. This randomized study analysed the in-vitro development of human embryos obtained after IVF in the presence or absence of a combination of amino acids from the 2- to 4-cell stage to the blastocyst stage. A total of 129 human embryos was randomly distributed between three serum-free chemically defined sequential media: (i) glucose-free Earle's balanced salt solution (EBSS) with glutamine (Gln) prior to morula stage, supplemented with glucose for blastocyst formation; (ii) glucose-free EBSS with glutamine and non-essential amino acids (AA) for cleavage stage development, and supplemented with all 20 AA for blastocyst formation (Earle's+AA); and (iii) a sequential commercial medium containing amino acids (K-SCIM). Embryos were individually cultured for successive periods of 24 h. On day 6 of development, blastocysts were differentially labelled and the numbers of trophectoderm and inner cell mass cells, mitoses and dead cells were examined. Blastocyst development was similar for the three sequential media. The mixture of AA significantly increased total blastocyst cell numbers from 61.8 +/- 4.2 with Earle's+Gln to 99.3 +/- 8.4 with Earle's+AA and 100.2 +/- 9.4 with K-SCIM (P = 0.005). This increase was present in both the trophectoderm and inner cell mass lineages (P < 0.02). Furthermore, the dead cell index was significantly lower with Earle's+AA (P = 0.047).

Amino Acids↗
PubMed2001

Evidence of reduced single-stranded testicular sperm DNA from obstructive azoospermic men after 3 days of in-vitro culture.

The aim of the present study was to verify whether culturing testicular tissue, to obtain a higher percentage of motile spermatozoa and a better post-thaw recovery rate, affected the ratio between single/double-stranded sperm DNA and, consequently, DNA sensitivity to damage. Testicular biopsy samples from men with obstructive and secretory azoospermia, candidates for assisted reproductive treatment, were cultured for 72 h. The percentage of motile spermatozoa and the single/double stranded DNA ratio were assessed on the day of retrieval (day 0) and again on day 3. The single/double stranded DNA ratio was measured by the acridine orange (AO) staining method. Spermatozoa were classified as green (double-stranded chromatin) or red fluorescing (single-stranded chromatin). In obstructive azoospermia, median motility was 22% (range 10-44%) on day 0 and 50% (range 38-63%) on day 3 (P < 0.01). The median percentage of red stained spermatozoa was 53.5% (range 0.1-88%) on day 0 and 20% (range 2.7-99.9%) on day 3 (P < 0.05). No changes were observed in secretory azoospermia. The culture procedure from obstructive azoospermia not only increased the post-thaw recovery rate, as previously observed, but also reduced the portion of spermatozoa containing single-stranded DNA, thereby increasing the availability of double-stranded DNA spermatozoa for ICSI use.

Acridine Orange↗
PubMed2001

ART in HIV-infected couples: has the time come for a change of attitude?

Today, in developed countries, many HIV-infected people remain in good health thanks to antiviral medication. A growing number of them want to have children. Medical possibilities for preventing contamination of the partners of seropositive men, through assisted reproduction, and of children thanks to antiviral medicines during pregnancy, are summarized. These changes result in ethical considerations which lead the authors to question the conventional systematic medical advice against pregnancy and has encouraged them to assist reproduction for a number of these couples. Today, the balance between the importance of the message of prevention and the benefit for patients of being assisted in their desire for a child has tilted towards medical intervention. It would seem legitimate today to intervene in the most favourable situations rather than see these couples take the risk of spontaneous conception outside health care structures. This implies the need to adapt medical structures (separate laboratory, appropriate procedure, precise protocols). This approach, which is coherent from the scientific point of view, respects both the autonomy of people carrying HIV as well as the essential interests of the child, in being born uninfected, and also has the enormous advantage of allowing access to parenthood without destroying the consistency of the message of prevention of sexual contamination.

Attitude of Health Personnel↗
PubMed2001

Screening standards in assisted reproductive technologies. Is the British Andrology Society recommendation to recruit cytomegalovirus negative semen donors only, a reasonable one?

The British Andrology Society recently recommended the exclusion of all cytomegalovirus (CMV) seropositive semen donors to prevent the risk of congenital CMV infection. The recommendation is based on the results of recent studies that identified a high percentage of symptomatic congenital CMV infections in newborns of women with CMV seropositivity pre-existing to pregnancy and on the fact that CMV can be detected in semen of CMV seropositive men. These are not new data. CMV seropositive women can infect their fetuses with their own latent CMV strain that can reactivate, or with an exogenous strain that can be transmitted to them by a sexual partner, but also by contacts, for example with an excreting child. The efficiency of these various ways of transmission to the fetus and the factors that could influence this transmission are for the moment completely unknown. An infectious virus is recovered by culture in the semen of <5% of CMV seropositive men. Exclusion of a large population of donors on the sole criteria of a positive CMV serology introduces the general message that this part of the male population is also not suitable as possible partners in couples who have no fertility problems. The problem of congenital infection in neonates of CMV seropositive women is a complex one that has just begun to be investigated. No data exists concerning this risk in the setting of assisted reproduction. We think that alternatives to the drastic BAS recommendation exist and should be more deeply discussed.

Cytomegalovirus Infections↗
PubMed2001

[Genetic counseling versus genetic self testing: what challenges?].

The development of molecular genetics allows us to have access to an increasing number of informations on our own genetic code. This leads to a new form of medical activity, called predictive and preclinical medicine. It involves significant ethical stakes in terms of individual information and consent for the test as well as in terms of support for the patient which is summarized by the concept of "genetic council". The self-test, which bypasses this medical supervision, represents, for the patient becoming a consumer, a threat from the emotional point of view as well as from a social perspective (insurance, access to the working market). This analysis shows that the only real driving force for the development of the genetic self-test is commercial. To resist what is sometimes called "genetic shopping" one must consider an ethical, deontological and social priority.

Ethics, Medical↗
PubMed2000

Noninvasive assessment of glucose and pyruvate uptake by human embryos after intracytoplasmic sperm injection and during the formation of pronuclei.

OBJECTIVE: To improve in vitro culture conditions and human embryo selection before transfer after IVF with intracytoplasmic sperm injection (ICSI). DESIGN: A controlled, randomized, prospective study. SETTING: University hospital-based IVF-ET program. PATIENT(S): Couples undergoing ICSI. INTERVENTION(S): Culture of human embryos in the presence of 1 mM or 5.56 mM glucose and metabolic measurements with the use of noninvasive microfluorescence assays immediately after ICSI to the time of transfer. MAIN OUTCOME MEASURE(S): Embryo development, implantation rate, and glucose and pyruvate uptake. RESULT(S): Fertilization rates, early embryo development, and implantation rates were not significantly different between 1 mM and 5.56 mM glucose. Pyruvate uptake was significantly higher during the formation of the pronuclei, at 15 +/- 0.7 and 11.4 +/- 1.3 pmol/embryo/h for fertilized and unfertilized oocytes, respectively. Pyruvate uptake did not correlate with cleavage stage or embryo morphology. However, during the second day of incubation, pyruvate uptake was significantly higher for the untransferred embryos of pregnant women compared with nonpregnant women, at 17.9 +/- 1.5 and 10.8 +/- 1.0 pmol/embryo/h, respectively. CONCLUSION(S): The increased level of pyruvate uptake during fertilization reflects the increased demand for energy necessary for the formation of the pronuclei. However, the metabolic measurements could not improve the selection of embryos with the best implantation potential. Finally, the reduction of glucose concentration in the culture medium failed to improve embryo viability.

Embryo Implantation↗
PubMed2000

In vitro development and metabolism of the human embryo up to the blastocyst stage.

The preimplantation period begins with the fertilisation of the oocyte and ends with the formation of the blastocyst. During this period, several major events occur resulting in an embryo composed of pluripotent cells. These morphological changes correspond to changes in the embryonic metabolism. The cleavage stages are characterised by a low metabolism and the inability of the embryo to metabolise glucose. After the activation of the embryonic genome, there is a surge in the embryonic metabolism with increased demand for ATP. The embryo is then able to metabolise glucose. Recently, the importance of amino acids has been highlighted by experiments with mouse, hamster and bovine embryos. Amino acids have also been reported to benefit human embryo development in vitro. Some growth factors have been shown to play a role in human embryo development too. The importance of lipids or vitamins, however, is poorly investigated. Culture media have been developed to improve preimplantation development, but more information is required for adapting culture condition to embryonic requirements which hopefully will improve the outcome of in vitro fertilisation (IVF).

Amino Acids↗