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J F Guérin

Publications and source records attributed to J F Guérin.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of two blastocyst culture systems: coculture on Vero cells and sequential media.

OBJECTIVE: To compare two blastocyst culture systems: culture on Vero cells and sequential media in the same time period. DESIGN: Retrospective study. SETTING: Institutional practice assisted reproductive technology center. PATIENT(S): Ninety-nine selected patients undergoing IVF with blastocyst culture. INTERVENTION(S): In vitro fertilization and transfer of at least one expanded blastocyst after culture using either Vero cells or sequential media (S(2) medium). MAIN OUTCOME MEASURE(S): Blastocyst, pregnancy, and implantation rates. RESULT(S): The blastocyst formation rate (41.6% vs. 31.6%) is significantly increased with sequential media compared with the coculture system, but there is no statistically significant difference in the pregnancy and implantation rates (39.5% vs. 38.6% and 23.7% vs. 15.1%, respectively). CONCLUSION(S): Blastocyst culture on sequential media offers a better dynamic of embryo development (22% vs. 13.6% blastocyst at day 5). There was no statistically significant difference between the two groups in the take-home baby rate (18 vs. 12).

Adult↗
PubMed2000

Regional methylation of the 5' end CpG island of BRCA1 is associated with reduced gene expression in human somatic cells.

In mammalians, demethylation of specific promoter regions often correlates with gene activation; inversely, dense methylation of CpG islands leads to gene silencing, probably mediated by methyl-CpG binding proteins. In cell lines and cancers, inhibition of tissue-specific genes and tumor suppressor genes expression seems to be related to such hypermethylation. The 5' end of the breast cancer predisposition gene BRCA1 is embedded in a large CpG island of approximately 2.7 kb in length. In human sporadic breast cancers, the down-regulation of BRCA1 does not seem to be related to BRCA1 gene alterations. Southern blot analysis and the bisulfite sequencing method indicate that the BRCA1 CpG island is regionally methylated in all human tissues analyzed and unmethylated in the gametes, suggesting a role for DNA methylation in the control of gene expression. We have therefore investigated the potential role of methyl-CpG binding proteins in the regulation of BRCA1 gene expression. In vitro, partial methylation of constructs containing this region strongly inhibits gene expression in the presence of MeCP2 protein. Moreover, in the five human cell lines analyzed, chemically induced hypomethylation is associated with BRCA1 gene activation. These data suggest that methyl-CpG binding proteins might be associated with the control of BRCA1 gene expression and that methyl-DNA binding proteins may participate in the regulation of gene expression in mammalian cells.

Azacitidine↗
PubMed1996

Uterine rupture in first or second trimester of pregnancy after in-vitro fertilization and embryo transfer.

We report five cases of early rupture of cornual pregnancy with history of previous salpingectomy and cornual resection following in-vitro fertilization (IVF) and embryo transfer. We discuss the predisposing factors, diagnostic and therapeutic modalities in these patients. A high index of suspicion is required for an early diagnosis. It is imperative that the physicians who care for the patients be fully aware of the possibility of such a complication in a high risk population; therefore, appropriate counselling and close follow-up might help to avoid such obstetrical catastrophes, by termination of pregnancy, either surgically or medically.

Adult↗
PubMed1996

Effects of progesterone on human spermatozoa prepared for in-vitro fertilization.

Progesterone has been tested in vitro with human spermatozoa to verify its physiological effects and its possible therapeutic use in cases of male infertility. Progesterone induced a rapid, dose-dependent influx of calcium in capacitated and non-capacitated spermatozoa with a half-maximally effective dose of 30 nM. The agonist, 19-nortestosterone, was much less potent that progesterone itself. Progesterone-induced calcium influx was not inhibited by a similar concentration (0.1 microgram/ml) of RU 486, a classical progesterone antagonist. The increase in intracytoplasmic calcium levels was unable to induce the acrosome reaction (AR) even after incubation for 5 h, when this was evaluated by double staining, using a monoclonal antibody GB24 raised against the inner acrosome membrane and ethidium homodimer as a vital probe. However, after incubation for 5 h, progesterone was able to enhance the tyrosine phosphorylation of a 95 kD sperm protein, which is phosphorylated progressively during capacitation in well-defined culture media. Incubation of spermatozoa with 1 or 10 micrograms/ml progesterone for 3 or 30 min did not induce major modifications of hyperactivated movement when analysed by computer-assisted semen analysis. Progesterone secreted by cumulus cells may physiologically increase sperm intracytoplasmic free calcium during capacitation. This priming effect may facilitate the acrosome reaction, induced by binding to the zona pellucida, without enhancing spontaneous acrosome reaction prematurely. It therefore seems useful to propose progesterone as a means of accelerating capacitation during in vitro fertilization in cases of male infertility.

Acrosome↗
PubMed1995

Morphological and cytogenetic observations of unfertilized human oocytes and abnormal embryos obtained after ovarian stimulation with pure follicle stimulating hormone following pituitary desensitization.

Morphological and cytological observations of 189 unfertilized oocytes and 40 abnormal embryos obtained from 32 patients in a routine in-vitro fertilization programme were performed. Both the oocytes and the embryos were mounted whole to preserve the original topology of all the structural elements. With the applied protocol of ovarian stimulation associating pituitary desensitization and follicle stimulating hormone stimulation, a high degree of immaturity of the unfertilized eggs was observed in comparison with previous reports. This immaturity was deduced from the higher incidence of unfertilized eggs arrested at the germinal vesicle or metaphase I stage, as well as metaphase II oocytes with multiple metaphase plates. Nine triploid and four tetraploid embryos were analysed: except for one tetraploid embryo, all the polyploid embryos cleaved. The percentages of mononucleated blastomeres in these polyploid embryos were 57 and 27% respectively. We also analysed 21 cleaving diploid embryos which exhibited a high degree of fragmentation. No more than 40% of the blastomeres contained a single nucleus. Moreover, in only one of the 21 diploid embryos could all the blastomeres be considered normal.

Blastomeres↗
PubMed1993

[Normal sperm].

The evaluation of male infertility rationally begins with a study of the characteristics of the semen, notably sperm count and motility assessment. However, this examination is difficult to interpret due to the important intra- and interindividual variability of these parameters, making it impossible to determine accurately the criteria of "normality". In each given subject the characteristics of semen can be influenced by the conditions of sample collection, the length of abstinence, and any disease that may have occurred in the 3 months preceding the examination. To draw firm conclusions from one single examination would be misleading and a second examination is advised. The criteria of normality laid down by WHO are not very useful to determine the degree of fertility in males: one may speak of oligozoospermia when the sperm count is below 20 million/ml, but several recent prospective studies have shown that fertility significantly falls only below 5 million/ml. A threshold value concerning the percentage of normal forms has been established at 30-40%, whereas teratozoospermia has been defined by the WHO as from 50% onwards. Sperm count can be completed by a fine analysis of sperm motions, and this has been made possible by the development of digital microvideographic analysis techniques. However, defining norms for the main parameters of sperm motility is delicate and can only be done by teams of specialists.

Fertility↗
PubMed1993

[Value of plasma progesterone (rapid assay) during ovarian stimulation for in vitro fertilization using LHRH agonists and hMG].

We have studied all the cycles (= 276) induced for in vitro fertilization using a LHRH agonist and the hMG (113 short protocols, 163 long protocols) from 01.90 to 07.90 to know the plasmatic profiles of the estradiol (E2), of the LH and specially of the progesterone (P) between J-7 and the day of the hCG (= J0). We observe in the short protocol an elevation (effect flare up) and afterwards a fall concomitant of the P and of the LH up to J-5, J-6 (effect of pituitary down regulation), in the short and long protocols a progressive elevation of J-3 up to J0 of the P parallel to E2, so that the LH remain stable or decrease. The LH of J0 is higher in short protocol than in long protocol (10.14 +/- 2.9 versus 4.72 +/- 1.3 Ul/l, p < 0.00001). We found the same progressive elevation of the P of J-3 up to J0 in pregnant and not pregnant patients. The surveillance of the P coupled to the E2 and to the follicular ultrasonography could help in the choice of the day of the hCG and avoid a post-maturity of oocyte. The consequences of the elevation of P In the morning of J0 have been study for P levels < 1 ng/ml (73 cases) and P > or = 1 ng/ml (203 cases) and afterwards for progressive elevation of P levels (1.5-2-2.5-3 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Study of different components in spermatic function after failure of in vitro fertilization].

The fertilizing potential of sperm depends on numerous properties which influence its functional competence. In order to understand the causes of IVF failure, we studied some of these properties-movement characteristics, hyperactivated motility, acrosome reaction-for infertile sperm (0% in vitro fertilization) and compared to those of fertile sperm (> or = 50% fertilization, control group). Movement characteristics, assessed by video-micrographic analysis, are significantly different for the 2 groups: infertile sperm register the lowest values for motility characteristics and hyperactivation. The addition of ionophore A23187 to the medium improves the hyperactivation and the acrosome reaction, the values for the latter, however, remain significantly lower compared to the control. These results are in favor of a detailed study of motility and induced acrosome reaction as complement for the diagnosis of male infertility.

Acrosome↗
PubMed1992

Motility and fertilizing capacity of epididymal human spermatozoa in normal and pathological cases.

OBJECTIVE: To investigate different factors involved in the outcome of in vitro fertilization (IVF) with epididymal spermatozoa in cases of vas deferens agenesis, with particular emphasis on sperm movement parameters. DESIGN: Prospective study in which sperm movement characteristics, level of puncture, and sperm preparation technique were studied relative to the outcome of IVF. SETTING: Département de Gynécologie, Oncologie Gynécologique, Sénologie, Médecine de la Reproduction, Hôpital Edouard-Herriot, Lyon France. PATIENTS: Thirteen couples underwent 15 IVF cycles. In 14 cycles (12 patients) epididymal spermatozoa could be recovered by surgical punctures. Epididymides were taken from 10 subjects in state of cerebral death to study epididymal spermatozoa under physiological status of the epididymis. RESULTS: The cleavage rate in IVF was low (25/158: 15.8%). In seven cases, embryo transfer was possible, leading to two twin pregnancies (4 infants born). Fertilization could be achieved with spermatozoa from the epididymis caput. Motility was paradoxically higher in the proximal epididymis than in the distal epididymis. In healthy epididymides, spermatozoa collected from the caput did not exhibit any progressive motility, whereas progressive motility was always present in the epididymis corpus. CONCLUSIONS: Our study showed that forward motility could be observed in the epididymis caput in patients with congenital absence of the vas deferens and that fertilization and ongoing pregnancies could be obtained from caput spermatozoa. On the other hand, in physiological status of the epididymis, forward motility was observed only as from the corpus area, confirming observations in other species.

Adult↗
PubMed1991

[The value of the level of alpha-1,4-glucosidase and seminal l-carnitine in patients with oligoasthenospermia].

Samples of sperm have been obtained from 95 who consulted us for infertility. In each case seminal plasma was examined for levels of alpha-1,4-glucosidase and L-carnitine. Our results have led us to fix the threshold value of 42.6 mlU per ejaculate for alpha-1,4-glucosidase and 960 nanomoles of L-carnitine below those levels that we thought occur where the origin of the oligospermia is obstructive (series 1 patients). In series 2 patients the cause of the oligospermia purely being secretory, there is normal epididymal function and therefore the excretory doubts are proven. It is not impossible to have both pathologies because we have found this in men of the intermediate groups C and D. We have found that there is a correlation between the presence of epididymal pathology and a drop in epididymal markers which can be found in severe oligospermia (which can be epididymal in origin and not testicular). Also when there is non abnormalities in the spermogram. This last situation can occur in "invisible" abnormalities of spermaturation in the epidymus.

Biomarkers↗