Biomedical subjects

Y Englert

Publications and source records attributed to Y Englert.

At least 37 records · Page 2Linked to original sources

PubMed2000

Increased sperm motility after in-vitro culture of testicular biopsies from obstructive azoospermic patients results in better post-thaw recovery rate.

The objective of this study was to optimize the use of testicular biopsies in 14 patients with obstructive azoospermia. Testicular specimens were retrieved from six patients (group I) and cultured at 32 and 37 degrees C for up to 20 days; changes in percentage motile spermatozoa were compared. In four men of group I, one portion of the specimen was frozen at retrieval, and changes in post-thaw motility after 24 h of culture at 37 degrees C were recorded. In the other eight patients (group II), testicular specimens were frozen at retrieval and after 72 h culture at 37 degrees C. Pre and post-freezing motility and post-thaw recovery rate were compared. No significant differences were observed until day 8 in the improvement of motility between 32 and 37 degrees C in-vitro culture. Maximum motility was reached, under both conditions, between 48 h and 72 h. Post-thaw 24 h culture at 37 degrees C of specimens frozen at retrieval did not improve motility; however, 72 h pre-freezing culture significantly improved initial motility (P: < 0.01), post-thaw motility (P: < 0.01) and post-thaw recovery rate (P: < 0. 001). The higher recovery rate of samples frozen 3 days after retrieval allows more economical use of the tissue that is available.

Biopsy↗

PubMed2000

Sigmoid endometriosis and ovarian stimulation.

In-vitro fertilization (IVF) and ovarian stimulation are frequently performed in patients with endometriosis. Although endometriosis is a hormone-dependent disease, the rate of IVF complications related to endometriosis is low. We report four cases of severe digestive complications due to the rapid growth of sigmoid endometriosis under ovarian stimulation. In three patients, sigmoid endometriosis was diagnosed at laparoscopy for sterility. Because of the absence of digestive symptoms or repercussion on the bowel, no bowel resection was performed before ovarian stimulation. All patients experienced severe digestive symptoms during ovarian stimulation, and a segmental sigmoid resection had to be performed. Analysis of endoscopic and radiological data demonstrated that bowel lesions of small size may rapidly enlarge and become highly symptomatic under ovarian stimulation. At immunohistochemistry, these infiltrating lesions displayed high populations of steroid receptors and a high proliferative index (Ki-67 activity), suggesting a strong dependence on circulating ovarian hormones and a potential for rapid growth under supraphysiological oestrogen concentrations. Clinicians should be aware of this rare but severe digestive complication of ovarian stimulation. The early diagnosis of such lesions may help the patients to avoid months of morbidity falsely attributed to ovarian stimulation side effects. Further experience is necessary to determine the optimal attitude when diagnosing a small and asymptomatic endometriotic bowel lesion before ovarian stimulation.

Adult↗

PubMed2000

Comparison of ethylene glycol, 1,2-propanediol and glycerol for cryopreservation of slow-cooled mouse zygotes, 4-cell embryos and blastocysts.

The aim of the study was to analyse the toxicity, the osmolar and cryoprotective activity of ethylene glycol (ETG) in terms of survival rate (SR), cleavage rate (CR) and expanded blastocysts percentage (EBP) of mouse embryos. Early mouse embryos and blastocysts were slowly cooled with ETG, 1,2-propanediol (PROH) or glycerol, and thawed. The Van t'Hoff curve for 1.5 mol/l ETG showed recovery of initial volume within 4 min. No differences were observed in CR and EBP of ETG-exposed compared with non-exposed mouse zygotes. The SR of zygotes frozen with PROH was significantly better than with ETG (92% and 60% respectively; P < 0.01), and a significantly better EBP was achieved for blastocysts frozen with glycerol compared with ETG (75% and 50% respectively; P < 0.05). For 4-cell stage embryos, no differences were observed in SR and EBP between ETG and PROH. Higher EBP was observed for 4-cell stage embryos (53%) frozen with ETG compared with pronucleate stage (19%) and blastocysts (48%). Low toxicity, good SR and EBP were observed for mouse embryos frozen with ETG, the best results being obtained at the 4-cell stage. At other embryonic stages, PROH and glycerol respectively seemed to provide better results.

Animals↗

PubMed2000

Re-analysis by fluorescence in situ hybridisation of spare embryos cultured until Day 5 after preimplantation genetic diagnosis for a 47, XYY infertile patient demonstrates a high incidence of diploid mosaic embryos: a case report.

Mosaicism in 4-8-cell human embryos analysed by fluorescence in situ hybridisation (FISH) has been widely reported, but few studies have addressed the incidence of mosaicism in more advanced embryonic stages. In the present study we analysed spare human embryos in a case of preimplantation genetic diagnosis (PGD) for increased risk of aneuploidy because of an infertile 47,XYY man. After replacement of two embryos typed as 1818XX at PGD, six spare embryos (not frozen because of their low quality) were re-analysed on Day 5 for PGD confirmation. Out of five embryos typed as 1818XY at PGD, four were diploid mosaic (DM) and one was normal in all cells. The sixth embryo, typed as 18XYY/1818181818X at PGD, was a DM. In spite of the bias of our small series of morphologically low-quality embryos, the surprisingly high proportion of mosaics (which confirms previous findings) questions the validity of PGD, but supports the strategy of transferring only the embryos where two blastomeres gave normal and concordant results at PGD. More data are required to understand the clinical significance of early diploid mosaicism (and its impact on implantation rate) and to determine whether some diploid mosaic embryos might be considered safe for transfer.

Adult↗

PubMed1999

HIV-1 infectivity and host range modification by cathepsin D present in human vaginal secretions.

OBJECTIVE: To investigate HIV-1 infectivity in the natural environment of vaginal secretions. DESIGN: Vaginal wash samples collected from 14 healthy women were incubated in vitro with various HIV-1 strains for 10 min at 37 degrees C and then assayed for infectivity on primary lymphocyte cultures, or on CEM cells, or on CD4- ME180 cells derived from vaginal epithelium. METHODS: HIV-1 infectivity was measured by early virus growth in the various host cells tested using a quantitative p24 assay and by the Karber procedure. RESULTS: Preincubation of HIV-1(IIIB) with vaginal wash samples or 2 microg/ml cathepsin D increased the ability of the virus to grow in lymphocyte cultures. The vaginal wash effect was abolished by 5 microg/ml pepstatin A, an inhibitor of aspartyl proteases. Presence of precursor and mature forms of cathepsin D in vaginal wash was demonstrated after passage through a pepstatin A-agarose column. Median tissue culture infective doses of HIV-1(IIIB) and HIV-1(JRFL) strains were increased 14.4-fold and 18-fold, respectively, after preincubation in vaginal wash sample, and were increased by pretreatment with 2 microg/ml cathepsin D. When CD4 receptors of CEMss cells were blocked by OKT4a monoclonal antibody, the cells lost susceptibility to HIV-1 (IIIB), but supported the growth of virus pretreated with vaginal wash sample or cathepsin D. These treated viruses were able to initiate infection of CD4-ME180 epithelial cells, which were not receptive to untreated virus. ME180 cells were shown to possess the messenger of CXC-chemokine receptor-4. CONCLUSIONS: Vaginal secretions may help HIV-1 transmission to women by increasing infectivity for CD4+ cells and allowing entrance into some CD4-epithelial cells.

CD4-Positive T-Lymphocytes↗

PubMed1999

Randomized autocontrolled comparison of the embryo culture performance of Nunc and Falcon petri dishes.

PURPOSE: Our purpose was to compare the embryo culture performance of two types of petri dishes (Nunc and Falcon). METHODS: Mouse zygotes were cultured up to the expanded blastocyst stage in both types of dishes. The oocytes from 50 in vitro fertilization cycles were randomly divided between the two types of dishes. Fertilization, cleavage, and embryo quality were compared. Oocytes from another 50 cycles were all cultured at random in either type of dish. Pregnancy and implantation rates were compared between the two types. RESULTS: Of 91 mouse zygotes, 81 cleaved to two-cell-stage embryos, and 64 became expanded blastocysts in Falcon dishes; of 99 zygotes, 81 cleaved to two-cell-stage embryos and 66 became expanded blastocysts in Nunc dishes. Of 248 oocyte-cumulus complexes (OCC), 145 fertilized in Falcon dishes, and of 269 OCC, 175 fertilized in Nunc dishes. The high quality embryo ratio was 51 out of 118 in Falcon dishes, not different from that in Nunc dishes, 58 out of 139. In Falcon dishes 72 out of 118 embryos were at least at the four-cell stage after 45 hr, versus 70 out of 139 in Nunc dishes. Twenty-three clinical pregnancies were obtained in the first 50 cycles with sibling oocytes. In the second group, with randomization of the cycles between Nunc and Falcon, 8 pregnancies were obtained in the Nunc and 10 in the Falcon dishes. The implantation rate in this second group of 50 cycles was 9 out of 61 in Falcon and 11 out of 57 in Nunc dishes.

Animals↗

PubMed1999

The outcome of cryopreserved human embryos after intracytoplasmic sperm injection and traditional IVF.

OBJECTIVE: Our objective was to analyze the outcome of cryopreserved embryos obtained after intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) in terms of survival rate, implantation rate (IR), total and clinical pregnancy rate (PR) in a retrospective, comparative study. METHODS: Three hundred seventy-five IVF and 463 ICSI surnumerary cleaved embryos, frozen on Day 2 with 1,2-propanediol, were thawed. RESULTS: Thirty-two percent of the thawed IVF embryos survived and 11 pregnancies (8 clinical) were obtained from 68 transfers (16.1%). Fourty-seven percent of the ICSI embryos survived, with 19 pregnancies (18 clinical) from 116 transfers (16.4%). The IR was 8.5% (8/94) in IVF cycles and 10.8% (20/185) in ICSI cycles. CONCLUSIONS: A significantly better survival rate of ICSI embryos was observed but with no difference in PR, preclinical, and clinical abortion rate, or IR.

Adult↗

PubMed1999

Comparison of two elective transfer policies of two embryos to reduce multiple pregnancies without impairing pregnancy rates.

A first elective transfer policy of two embryos based solely on embryo morphology was compared to a more restrictive policy transferring two embryos to all patients aged < 35 years with less than three previous cycles to reduce the incidence of multiple pregnancies. With a significant reduction in the number of triple transfers from 72.4 to 44.3%, the delivery rates were similar for both policies, 31 and 32.1%. However, the multiple pregnancy rates per transfer significantly decreased from 12.5 to 7.8% (P < 0.05). Of 99 pregnancies, only 24.2% were multiple including 1% of triplets compared to 40.7% multiple pregnancies including 6.7% of triplets for the first policy. Forty-eight transfers of two average embryos with the new policy were compared to 264 transfers of three average embryos with the old policy. Multiple pregnancy rates per transfer were significantly reduced by a third from 23 to 8% (P < 0.05) without a reduction of the pregnancy rates (42 and 48%). This study demonstrated that elective transfer of two embryos reduced the number of multiple pregnancies without impairing the pregnancy rates even with the transfer of average embryos.

Adult↗

PubMed1999

Selection of good embryos for transfer depends on embryo cohort size: implications for the 'mild ovarian stimulation' debate.

Embryo quality evaluated by the embryo morphology is a critical parameter in human in-vitro fertilization (IVF) and embryo transfer. It determines which and how many embryos will be replaced, as pregnancy rates are directly related to number and quality of transferred embryos. This retrospective analysis included 1301 IVF and embryo transfer cycles to identify which factors influenced embryo quality. Embryo quality did not correlate with maternal age, causes of infertility, ovarian stimulation parameters or embryo cohort size. However, the mean score of transferred embryos was significantly higher for patients with more than five embryos compared to fewer than five embryos (P < 0.001), irrespective of maternal age. Patients tended to produce a similar embryo quality from cycle to cycle, r = 0.33 (P < 0.001) for the embryo cohort and r= 0.47 (P < 0.001) for the transferred embryos. Poor embryo morphology probably reflects oocytes with compromised development competence and could be an independent factor of infertility. Furthermore, a large embryo cohort was the main factor increasing the chances of at least one good embryo in the cohort.

Adult↗

PubMed1999

Effects of taurine on human embryo development in vitro.

Glutamine and taurine are reported to be beneficial for mouse embryo development in vitro, and we have recently shown that glutamine improves human blastocyst formation in vitro. This randomized study compared the development of supernumerary human embryos in the presence of 1 mmol/l glutamine and/or 5 mmol/l taurine from the 2-4-cell stage to the blastocyst stage. Blastocyst development and cell numbers were similar in the presence of glutamine or taurine: 52.6% and 58.3% of the embryos reached the blastocyst stage, respectively. Pyruvate uptake was similar in the presence of glutamine or taurine throughout development, as was lactate production after the 8-cell stage. Before this stage, lactate production was 4-fold higher in the presence of taurine (P < 0.001). The proportion of embryos reaching the blastocyst stage was similar with glutamine alone or with glutamine and taurine (62.5% and 47.2% respectively), as were the blastocyst cell numbers (63.0 +/- 4.6 and 61.0 +/- 5.1 respectively). In conclusion, taurine supports development of 2-4-cell human embryos to the blastocyst stage, although it does not further augment the beneficial effects of glutamine.

Blastocyst↗

PubMed1999

[In vitro fertilization at the Erasme Hospital: 10 years and 1000 pregnancies later...].

This contribution summarize ten years of in vitro fertilization of clinical work. Activity growth, improvements of results (mean fertilization rate increased from 45% to 58%, fertilization failure dropped from 18% to 7%, pregnancy chances gains 9% to reach 44% per trial) and new treatments possibilities (severe male infertility) thanks to the ICSI technic were the major characteristics of this last ten years. The original anonymous oocyte donation program with donors permutation initiated as soon as 1990 has imposed itself due to it's exceptional efficiency with a pregnancy rate of 95% per oocyte pick up on a population of 46 donors and 145 recipient cycles. Thanks to the large population studied (4028 cycles, 1071 pregnancies), the tendencies in human fecundity (impact of age) and the risks linked to multiples pregnancies could be highlighted, stressing the importance of future developments presented in the other contributions following this general presentation of results.

Adult↗

PubMed1999

[Evolution of ovarian stimulation in in vitro fertilization].

This paper reviews the different treatments of ovarian stimulation for in vitro fertilization (IVF). It emphasizes the recent development of new molecules, including recombinant gonadotrophins and GnRH antagonists. Because of their higher purity, recombinant gonadotrophins are theoretically less immunogenic than the urinary forms. Their preparation mode ensures a better batch to batch consistency. Their clinical use in IVF seems to be associated with a higher number of developing follicules and retrieved oocytes, but pregnancy rates are comparable to those obtained after ovarian stimulation with urinary gonadotrophins. The GnRH antagonists induce a direct inhibition of the pituitary gonadotrophin secretion. In association with an ovarian stimulation with gonadotrophins, they efficiently prevent premature LH surges when administered during the end of the follicular phase. The GnRH antagonists are still in clinical evaluation phase and the optimal protocol and dose still to be defined. They should become available in the coming year. The risks related to the controlled hyperstimulation together with the reduction of the number of transferred embryos has recently led "soft stimulation" to a reevaluation of the stimulation protocols towards a simplified procedure. However, the validity of this attitude could be in opposition with the wish to limit the number of transferred embryos since embryo quality seems to be directly related to the total number of embryos.

Clomiphene↗

PubMed1999

[Impact of the introduction of intracytoplasmic sperm injection (ICSI) on the treatment of severe male sterility].

The introduction of the Intracytoplasmic Single Sperm Injection (ICSI) has been a turning point for the treatment of severe male infertility. ICSI allowed not only to reduce fertilization failure from 35% to 0.7% but created at the same time the opportunity for a group of patients with extremely low sperm counts to procreate. The discovery that breaking the tail of the spermatozoon prior to the injection was the most important step is at the origin of major improvements: fertilization increased from 22% to 77%, pregnancy rate from 16% to 54% and the implantation rate from 7.4% to 26%. From October 1994 to April 1999, 835 ICSI cycles were performed and resulted in 312 ongoing pregnancies (37%), fertilization rate was 75%, with a fertilization failure of only 0.7%. The use of ICSI and IVF on sibling oocytes for semen samples with doubtful fertilizing ability clearly illustrated the superiority of ICSI. No fertilization failures occurred after ICSI and the fertilization rate was 76% versus 27.8% (P < 0.01). Similar benefit of ICSI was shown for crytozoospermia up to then a hopeless situation. A total of 26 pregnancies were obtained out of 87 cycles with a fertilization rate of 58.8%. Similar results were obtained when ICSI was combined with testicular sperm, 20 pregnancies occurred after from 46 transfers (43%) including cycles with cryopreserved testicular sperm. It is now clear that ICSI is the method of choice for the treatment of severe male infertility.

Belgium↗

PubMed1999

[Diminishing the risk of multiple pregnancies in in vitro fertilization: from selective transfer of two embryos to that of one blastocyst?].

The risk of multiple pregnancy after IVF needs to be drastically reduced. Several policies can be applied including the transfer of a maximum of three embryos to all patients, the fertilization of a maximum of three oocytes or a selective reduction of the number of transferred embryos. The first policy previously applied at the Fertility Clinic at Erasme Hospital until 1996, transferred two good quality embryos to patients with at least three good embryos. If this policy demonstrated that patients with two transferred embryos had similar chances of pregnancies compared to patients with three transferred embryos, it failed to sufficiently decrease the number of multiple pregnancies. The second policy applied since 1997, transferring a maximum of two average or good embryos to all patients aged under 35 years and with less than 3 previous attempts, demonstrated that while preserving the chances of pregnancy for these patients, it decreased by 20% the number of multiple pregnancies and almost eliminated triplets. With the improvement of culture media, it is now possible to culture embryos in vitro for a longer period and therefore transfer embryos with proven viability at a time corresponding more to in vivo physiological conditions. The implantation rates for these embryos, for patients with at least 4 previous attempts can reach 40%. If these results persist, it would be possible to transfer blastocysts to all patients and perhaps move on to the replacement of a single embryo, a policy that will practically eradicate all multiple pregnancies.

Adult↗

PubMed1999

[Aspects of scientific research and technical progress in human fertility].

The development of an outstanding in vitro fertilization program greatly benefits from the contribution of research because it remains an unfailing source of questions on human reproduction, as much in the fields of physiology and pathology as in those of psychology and sociology. This paper shows five major themes that are tackled by the laboratory of biology and psychology of human fertility and the Fertility Clinic, whether it's endocrinology (the ovarian renin and angiotensin regulation), cellular metabolism (embryo metabolism), genetics (preimplantation genetic diagnosis) or cancerology (ovarian tissue conservation before or after chemo- or radiotherapy), all of these are crossed by the fifth (the psychological and ethical aspects of in vitro fertilization) which gives a human dimension to the biological work, since it's a very special biology that it's our own reproduction, the very base of the specie's survival.

Cryopreservation↗

PubMed1998

Short-term medical complications of 1500 oocyte retrievals for in vitro fertilization and embryo transfer.

OBJECTIVE: To evaluate the different short-term complications after in vitro fertilization and embryo transfer. DESIGN: a retrospective study on 7 years in the fertility clinic of an university hospital. MATERIALS AND METHODS: Short-term medical complications were analysed after 1500 transvaginal ultrasonographically guided oocyte retrievals. RESULTS: Ovarian hyperstimulation syndrome (1.8%), pelvic infections (0.4%), intraperitoneal bleeding (0.2%) and adnexal torsions (0.13%) were observed. One case of adnexal torsion occurred during pregnancy (0.18%). Two unusual case of bowel endometriosis were encountered (0.13%). CONCLUSIONS: Short-term medical complications after in vitro fertilization and embryo transfer are rare (2.8%). This contrast with the high rate of multifetal pregnancies which increases maternal and perinatal morbidity and mortality and must be considered as the major complication of in vitro fertilization treatment.

Adnexal Diseases↗

PubMed1998

A first prospective study of the individual straight line velocity of the spermatozoon and its influences on the fertilization rate after intracytoplasmic sperm injection.

The straight line velocity of 500 individual spermatozoa was measured immediately before their direct injection into the cytoplasm of 500 metaphase II oocytes. The straight line velocity (VSL) did not have a normal distribution (P < 0.01) and ranged between 0 and 35 microm/s. The fertilization rate (84%) was significantly (P < 0.008) higher in the quartile of the sperm population with the highest VSL compared to the fertilization rate (68%) in the quartile with the lowest VSL. Embryo cleavage and embryo quality were not different in the quartiles of the sperm population used for injection.

Cleavage Stage, Ovum↗

PubMed1998

Comparison of pregnancy outcome after intracytoplasmic sperm injection and in-vitro fertilization.

The aim of this study was to compare pregnancy characteristics and perinatal outcome of intracytoplasmic sperm injection (ICSI) pregnancies with pregnancies obtained after in-vitro fertilization (IVF). Retrospectively, 145 ICSI pregnancies were matched with 145 IVF pregnancies using the last menstruation data. The main outcome measures were preclinical and clinical abortions, ectopic pregnancies, multiple gestations, prenatal morbidity, prematurity, Caesarean section, birthweight, perinatal mortality and malformations for singletons, twins and triplets. Although patients were significantly younger (P < 0.001) in ICSI (31 years) than in IVF (33 years), their infertility duration (5 years) was similar. The mean number of transferred embryos (2.7 embryos per transfer) was similar in IVF and ICSI. The rates of preclinical (15%) and clinical abortions (11% in ICSI versus 15% in IVF) were not different. Four ectopic pregnancies were observed in the IVF group and none in the ICSI group. In ICSI, two minor malformations were detected and two therapeutic abortions were performed respectively for polymalformations and suspicion of cystic fibrosis. The rate of congenital malformation was 2.8% in ICSI and 2.2% in IVF. In this last group, one therapeutic abortion for malformation of neural tube was performed and two minor malformations were detected. The rate of aborted embryonic sacs before 16 weeks of gestation was not significantly lower in ICSI compared with IVF (13.7% versus 20%). The rate of multiple gestations was similar in both groups (31% in IVF and 35% in ICSI). The number of Caesarean sections was similar in IVF and in ICSI and was twice as frequent for twins versus singletons. The number of singletons born by Caesarean section was 21% after ICSI and 17% after IVF. Mean birthweights and gestational ages at birth for twins were significantly higher (P < 0.05) in ICSI than in IVF (2488 versus 2281 g and 36.5 versus 35.5 weeks). This difference was not observed for singletons. In conclusion, pregnancy characteristics and perinatal outcome after ICSI showed no increase in the number of pathologies in comparison with IVF.

Adult↗