Biomedical subjects

Yvon Englert

Publications and source records attributed to Yvon Englert.

15 recordsLinked to original sources

PubMed2006

Development and evaluation of a qualitative reverse-transcriptase nested polymerase chain reaction protocol for same-day viral validation of human immunodeficiency virus type 1 ribonucleic acid in processed semen.

OBJECTIVE: To develop a method for same-day validation of processed semen in the setting of assisted reproductive techniques (ART) with patients who are seropositive for human immunodeficiency virus, type 1 (HIV-1). DESIGN: Laboratory experiments. SETTING: University hospital. PATIENT(S): Volunteers who are HIV-1 seronegative and seropositive. INTERVENTION(S): Evaluation of the sensitivity of a reverse-transcriptase (RT)-nested polymerase chain reaction (PCR) in HIV-1 RNA-positive blood plasma, in artificially infected blood plasma and semen, and in 85 semen samples of 29 HIV-1-seropositive volunteers. Semen was submitted to gradient separation, followed by swim-up. MAIN OUTCOME MEASURE(S): Qualitative detection of HIV-1 RNA in blood plasma and in different parts of semen preparation by using RT-nested PCR, PCR inhibition control by dilution of samples, and an internal control. RESULT(S): The detection limit of our PCR was 20 HIV-1 RNA copies per milliliter. Among seropositive patients, RNA was detected in 25% of fresh semen, 36.5% of seminal plasma, 27.5% of gradient supernatants, and 7.1% of final preparations before the migration-sedimentation stage. Positive final preparations were observed in patients who had blood viral loads of >/=20,000 HIV-1 RNA copies per milliliter. Inhibition was present in 17.6% of seminal plasma and in 20% gradient supernatants and in 2 final preparations among 69 tested. Among 25 preparations tested after the migration-sedimentation stage, 2 were positive (1 patient; 70,000 HIV-1 RNA copies per milliliter). CONCLUSION(S): The RT-nested PCR detects low viral load and allows the validation of semen preparations of HIV-1-seropositive patients for ART on the day of sampling. For this purpose, the validation is performed on spermatozoa that are obtained after gradient separation before swim-up. Inhibition of the PCR must be controlled by using an internal control that is well-designed to explore the detection limit of the method.

Cells, Cultured↗

PubMed2006

Ovarian function and spontaneous pregnancy after combined heterotopic and orthotopic cryopreserved ovarian tissue transplantation in a patient previously treated with bone marrow transplantation: case report.

Cryopreservation of ovarian tissue has been proposed for storing gametes of young patients at high risk of premature ovarian failure. Autotransplantation has recently provided some promising results and is still the unique option to restore ovarian function from cryopreserved ovarian tissue in humans. In this article, we analyse data from the combined orthotopic and heterotopic transplantation of cryopreserved ovarian tissue that restored the ovarian function and fertility. Orthotopic transplantation of cryopreserved ovarian tissue at ovarian and peritoneal sites, together with a heterotopic transplantation at the abdominal subcutaneous site, was performed to restore the ovarian function of a 29-year-old woman previously treated with bone marrow transplantation (BMT) for Hodgkin's disease. Ovarian reserve markers progressively suppress within values 5 months after the transplantation (basal FSH 5 mUI/ml and inhibin B 119 ng/ml). Follicular development was observed at all transplantation sites but was predominant at the ovarian site. Six natural cycles were fully documented and analysed. The patient became spontaneously pregnant following the sixth cycle, but unfortunately she later miscarried. Combined orthotopic and heterotopic transplantations succeeded in the restoration of normal spontaneous cycles. Furthermore, this spontaneous pregnancy confirmed the efficiency of this procedure for restoring human fertility.

Abortion, Spontaneous↗

PubMed2006

Multicenter quality control of the detection of HIV-1 genome in semen before medically assisted procreation.

Couples in whom the man is HIV-1-positive may use medically assisted procreation in order to conceive a child without contaminating the female partner. But, before medically assisted procreation, the semen has to be processed to exclude HIV and tested for HIV nucleic acid before and after processing. The performance was evaluated of the technical protocols used to detect and quantify HIV-1 in 11 centers providing medically assisted procreation for couples with HIV-1 infected men by testing panels of seminal plasma and cells containing HIV-1 RNA and/or DNA. The performance of these tests varied due to the different assays used. False positive results were obtained in 14-19% of cases. The sensitivity for RNA detection in seminal plasma was 500-1,000 RNA copies/ml, over 500 RNA copies/10(6) cells in semen cells, and for DNA detection in semen cells 50-500 DNA copies/10(6) cells. The use of silica-based extraction seemed to increase the assay performance, whereas the use of internal controls to detect PCR inhibitor did not. This first quality control highlights the need for technical improvements of the assays to detect and quantify HIV in semen fractions and for regular evaluation of their performance.

DNA, Viral↗

PubMed2006

Impact of the assessment of early cleavage in a single embryo transfer policy.

The policy of single embryo transfer (SET) adopted for women <36 years old since 1 July 2003, strongly calls for improvement of embryo selection. A total of 196 cycles in which SET was performed were randomly allocated to two groups. In the first group, early cleavage was assessed (ECA) 25 h after insemination. The embryo with the best score that cleaved early, if present, was selected for transfer. In the second group, early cleavage was not assessed (ECNA) and embryo selection was based solely on the embryo score. Ninety-eight cycles were allocated in the ECA and ECNA group respectively. Early cleavage occurred in 64% of cycles and 32.2% of embryos. Patient population and embryo morphology were similar between the two groups, and similar delivery rates were observed (27.6 versus 24.5% respectively in the ECA and ECNA groups). The assessment of early cleavage as additional parameter did not improve the delivery rate in the single embryo transfer policy.

Adult↗

PubMed2005

Laboratory safety during assisted reproduction in patients with blood-borne viruses.

For couples where one or both partners are infected with human immunodeficiency virus or hepatitis C, the doors to receiving fertility care are opening as a result of better antiviral medication, better long-term prognosis and consequent changes in attitude. In line with this, fertility centres electing to treat couples with blood-borne viral (BBV) infection need to re-examine their policies and procedures to ensure the safety of their staff and both non-infected and infected patients during assisted reproduction treatments. At a time when the European Tissue Directive aims to introduce quality standards for assisted reproduction throughout Europe, we highlight the risks involved when treating patients with known BBV infections and argue that safety cannot be met with any certainty unless samples from such patients are handled within a separate high security laboratory or laboratory area, technically adapted to ensure minimal cross-contamination risk to uninfected gametes and embryos.

Blood-Borne Pathogens↗

PubMed2005

Embryo-maternal interactive factors regulating the implantation process: implications in assisted reproductive.

The embryo-maternal dialogue that starts very early in the life of the embryo is crucial for its own implantation. A disturbance in this dialogue is the major reason for which 60% of all pregnancies are terminated at the end of the periimplantation period. Many studies have been performed to improve the understanding of the molecular mechanisms involved in this dialogue. Both partners, the mother and the embryo, are equally involved in this exchange of signals. Much progress has been done in understanding the role of (i) chorionic gonadotrophin, (ii) growth factors and cytokines, and (iii) steroid hormones and other mediators, produced either by the embryo, by the mother, or by both, during the peri-implantation period. Today it is clear that their production dictates changes in the endometrium, in the immunological system of the mother and in embryo metabolism, that enable the embryo to implant. Knowledge of the molecular mechanisms involved in the embryo-maternal interaction are reviewed in this article.

Blastocyst↗

PubMed2004

Comparison of the validity of preimplantation genetic diagnosis for embryo chromosomal anomalies by fluorescence in situ hybridization on one or two blastomeres.

Is it necessary to analyze two blastomeres in preimplantation genetic diagnosis (PGD) by fluorescence in situ hybridization (FISH) or is one blastomere enough, as suggested by some teams? We analyzed the sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), false positives (FP), false negatives (FN), and the efficiency (Eff) of FISH performed on one (Group I) or two (Group II) blastomeres. Ninety embryos were analyzed (day 3), 19 blastocysts were replaced (day 5), 64 embryos were reanalyzed (day 5), (Group I = 23; Group II = 41). No differences were observed between the two groups for all of the parameters considered, but one false negative was observed in Group I. Furthermore, two embryos from Group II, which had a discordant diagnosis at PGD (one blastomere being normal and one abnormal), were read as abnormal after reanalysis. The accidental biopsy of the normal blastomere could have lead to the selection of these 2 embryos for transfer, causing a misdiagnosis rate of 4.8%. We conclude that embryo reanalysis is a useful tool to test the reliability of PGD in each laboratory: that PGD on two blastomeres is safer because the practice of PGD on one blastomere can result in a false-negative misdiagnosis.

Blastomeres↗

PubMed2004

Prediction of severity of symptoms in iatrogenic ovarian hyperstimulation syndrome by follicle-stimulating hormone receptor Ser680Asn polymorphism.

The ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening complication of ovarian stimulation treatments for in vitro fertilization (i.v.f.). Recently, three different mutations of the FSH receptor (FSHr) have been identified in patients who presented recurrent spontaneous OHSS. This prompted us to study a possible association between coding polymorphisms of the FSHr and the occurrence of iatrogenic OHSS. We sequenced the region of the FSHr gene encompassing the A307T and S680N polymorphisms of exon 10 of FSHr in 37 Caucasian females who developed OHSS after an IVF cycle in our fertility clinic, 130 Caucasian female patients who were treated by i.v.f. but never developed OHSS, and 99 Caucasian female controls. The FSHr allele frequencies in the Caucasian control population were identical to what has already been published (39% S680 61% N680). The control i.v.f. population was enriched in the S680 allele compared with the Caucasian control population (51% S680; 49% N680; P = 0.016). The OHSS population had a even higher enrichment in the S680 allele compared with the Caucasian control population (57% S680; 43% N680; P = 0.010). These results were unexpected, because the frequency of the S680 allele was previously found to be increased among poor responders to FSH stimulation. In a second phase, we studied FSHr allele frequencies according to the severity of OHSS. Interestingly, a significant enrichment in the allele N680 was observed as the severity of OHSS increased (P = 0.034). Bearing in mind the limitations of the small number of patients studied and the possibility of sampling biases, these results suggest that the genotype in position 680 of the FSHr cannot predict which patients will develop OHSS, but could be a predictor of severity of symptoms among OHSS patients.

Adult↗

PubMed2003

A prospective longitudinal study of the physical, psychomotor, and intellectual development of singleton children up to 5 years who were conceived by intracytoplasmic sperm injection compared with children conceived spontaneously and by in vitro fertilization.

OBJECTIVE: To assess the somatic, psychomotor, and intellectual development of children conceived through intracytoplasmic single sperm injection (ICSI) over the whole preschool period. DESIGN: Prospective, controlled, cohort study. SETTING: Fertility clinic in Brussels, Belgium. PATIENT(S): Sixty-six ICSI-conceived children prospectively compared with 52 IVF-conceived and 59 spontaneously conceived children. All children were full-term singletons. INTERVENTION(S): Home visits by a trained psychologist. Standardized interviews. Assessments using the revised Brunet-Lézine scale and the revised Wechsler preschool and primary scale of intelligence. MAIN OUTCOME MEASURE(S): Physical growth and general health. Formal developmental and intellectual assessments. RESULT(S): Children conceived by ICSI were healthy: no significant differences appeared in the incidence of combined congenital malformations (11.3%), health problems (44.1%), surgical interventions (18.6%), and hospitalizations (6.8%), nor for the developmental assessments (mean developmental quotient at 9 months: 93.9; at 18 months: 102.0). For the intellectual assessments, the between-group differences disappeared when adjusted for levels of parental education (mean intelligence quotient at 3 years: 97.0; at 5 years: 103.3). CONCLUSION(S): This pilot study shows that throughout the preschool period, ICSI-conceived children have psychomotor and intellectual development similar to that of IVF-conceived and spontaneously conceived children. These conclusions need to be confirmed by multicenter studies.

Analysis of Variance↗

PubMed2003

Preliminary experience of ovarian tissue cryopreservation procedure: alternatives, perspectives and feasibility.

Chemotherapy and radiotherapy induce premature ovarian failure in many patients treated for oncological or benign diseases. The present paper reviews the risk of developing premature ovarian failure according to the type of treatment and the different options to preserve fertility, focusing on the cryopreservation of ovarian tissue. This technique constitutes a promising approach to preserve the fertility of young patients and offers the advantage of storing a large number of follicles that could be subsequently transplanted or cultured in vitro to obtain mature oocytes. Based on 34 requests, from which 19 were performed, the feasibility of the ovarian cryopreservation procedure is evaluated. The medical and ethical approaches of this protocol are also discussed. Cryopreservation of ovarian tissue constitutes new hope for many patients, but must still be kept for selected cases, with a significant risk of premature ovarian failure after treatments such as bone marrow transplantation.

Adolescent↗

PubMed2003

Higher degree of chromosome mosaicism in preimplantation embryos from carriers of robertsonian translocation t(13;14) in comparison with embryos from karyotypically normal IVF patients.

PURPOSE: To compare the frequency and the degree of mosaicism in human embryos from Robertsonian translocation (RT) t(13;14) carriers, with embryos from karyotypically normal IVF patients METHODS: FISH analysis of embryos from PGD cycles for RT t(13;14), with probes for chromosomes 13, 14, and 18 (Group I) and of embryos from karyotypically normal IVF patients with probes for chromosomes 13, 18, 21, X, and Y (Group II). RESULTS: The incidence of abnormal mosaic embryos was significantly higher in group I (38/51) as compared with group II (6/45) (chi2: P < 0.01). Furthermore, in group I the percentage of diploid cells per embryo was lower for chromosome 13 and 14 in comparison with 18, while in group II no differences were observed between the five chromosomes analyzed. CONCLUSIONS: RT induces a high frequency of mosaicism specifically for the chromosomes implicated in the translocation; the analysis by FISH of two blastomeres is strongly recommended for these patients

Adult↗

PubMed2003

Incidence of chromosomal mosaicism in human embryos at different developmental stages analyzed by fluorescence in situ hybridization.

Chromosomal mosaicism has been reported in in vitro-cultured embryos at early cleavage stages, as well as in morulae and blastocysts. We have assessed the incidence and pattern of mosaicism during in vitro development of human embryos from early-cleavage stages to morula and blastocyst. Fifty spare embryos were fixed for fluorescence in situ hybridization (FISH) analysis for chromosomes X, Y, 13, 18, and 21 on days 2 or 3 (4- to 10-cell stage) (n = 16), on day 4 (morula stage) (n = 14), on day 5 (pre-expanded blastocyst) (n = 5), and the expanded blastocyst stages (n = 15). Blocked embryos (no cleavage observed within the last 24 hr) were not included. A total of 2367 cells were analyzed. Four early-cleavage stage embryos were found uniformly diploid; all of the others were mosaic for the chromosomes analyzed (mean diploid nuclei 48.3% +/- 28.7). All of the embryos at more advanced developmental stages, except one fully normal morula, had mosaic chromosome constitutions, with an increase in the percentage of diploid cells in morulae, pre-expanded, and expanded blastocysts, respectively (mean diploid nuclei 78.6% +/- 11.7, 66.0% +/- 20.8, 79.6% +/- 12.8), in comparison with earlier stages. Hypotheses about the origin of mosaicism and embryo regulation mechanisms will be discussed.

Aneuploidy↗

PubMed2003

Similar delivery rates in a selected group of patients, for day 2 and day 5 embryos both cultured in sequential medium: a randomized study.

BACKGROUND: The existence of a real benefit of blastocyst transfer is still a matter of debate. The aim of this study was to compare, in a prospective randomized trial, the outcome of day 2 and day 5 transfer of human embryos cultured in an 'in-house' sequential medium. METHODS: A total of 193 cycles from 171 patients with less than four previous IVF cycles, <39 years old and with four or more zygotes on day 1, were randomly allocated to day 2 (94 cycles) or day 5 (99 cycles) transfer. Zygotes were kept in fertilization medium until 18 h post-fertilization and then placed in a 'glucose-free' cleavage medium. Embryos allocated for day 5 transfer were placed in a blastocyst medium 66 h post-fertilization. Two or three embryos were replaced according to the morphology. RESULTS: A mean (+/- SEM) number of 2.1 +/- 0.4 and 1.9 +/- 0.3 embryos were replaced on day 2 and day 5 (P < 0.001) respectively. Delivery rates per transfer were 44.1 and 37.1% [P = not significant (NS)], implantation rates were 31.4 and 29.4% (NS) and multiple delivery rates 22 and 36% (NS) for day 2 and day 5 groups respectively. Ten patients (10.1%) had no blastocysts available for transfer. CONCLUSIONS: No clear benefits were observed using blastocyst transfer for patients aged <39 years who had had less than four previous IVF cycle attempts.

Adult↗

PubMed2002

Correlation between fluorescence in-situ hybridization analyses and in-vitro development to blastocyst stage of embryos from Robertsonian translocation (13;14) carriers.

BACKGROUND: Little is known about the extent and timing of selection against the embryos that are carriers of unbalanced translocations. METHODS: Fluorescence in-situ hybridization (FISH) with probes for chromosomes 13, 14 and 18 was performed, mostly on day 3, on 69 human embryos which were then allowed to develop further in culture to day 5, from five carriers of Robertsonian translocation (RT) t(13;14). RESULTS: Twelve normal/balanced blastocysts were replaced in seven consecutive cycles (day 5). Three cycles resulted in clinical pregnancies. The proportion of blastocysts displaying a normal/balanced karyotype was 56%, while only the 20% of blocked embryos were normal/balanced (chi(2): P < 0.05). All the embryos analysed on day 5, except one, displayed mosaicism. The percentages of diploid cells for chromosomes 13 and 14 were significantly lower than for chromosome 18 (chromosome 13: 49.0 +/- 28.0; chromosome 14: 53.0 +/- 31.8; chromosome 18: 75.7 +/- 20.4; Mann-Whitney test: P < 0.01). The embryos displaying vertical line 62% of diploid cells for at least two of the three chromosomes analysed, more frequently reached the blastocyst stage (blocked embryos: blastocysts chromosome 13: 43.1 +/- 30.3, 64.9 +/- 29.0; chromosome 18: 64.9 +/- 29.0, 83.0 +/- 12.9; Mann-Whitney test: P < 0.01). CONCLUSIONS: Normal/balanced embryos developed better but the proportion of abnormal blastocysts was still high. Preimplantation genetic diagnosis is recommended to select normal/balanced embryos from RT t(13;14) carriers.

Adult↗

PubMedDate not supplied

Medically assisted reproduction in the presence of chronic viral diseases.

Teams practising medically assisted reproduction techniques try to avoid viruses as much as possible. Attitudes towards chronic carriers of viruses are rapidly changing, especially for human immunodeficiency virus (HIV) patients. We focus our attention on the legitimacy of systematic screening before assisted reproductive techniques and the need for specialized approaches including an adapted laboratory for viral hazards as well as the need for a multidisciplinary team. Specificities of HIV, hepatitis C virus (HCV), hepatitis B virus (HBV) carriers and the hypothesis of a reduced fertility potential are discussed. Are male HIV carriers a new indication for assisted reproductive techniques in order to prevent virus transmission? It is largely proven that sperm gradient preparation techniques efficiently decrease viral loads and therefore have a protective effect on contamination risk during assisted reproductive techniques. Although a few thousand assisted reproductive technique cycles were performed in the world for this indication without contamination, it is still too early to demonstrate that this technology is fully safe. Two examples of contaminations during insemination are examined. Many questions remain unresolved, such as the lack of standardized techniques for semen preparation or virus detection or the relative merits of intrauterine insemination or ICSI to prevent HIV contamination during assisted reproductive techniques. The authors plead for well-structured, separate programmes of care linked to research objectives.

Acquired Immunodeficiency Syndrome↗