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Biomedical subjects

J F Guerin

Publications and source records attributed to J F Guerin.

At least 19 recordsLinked to original sources
PubMed2006

Analysis by fluorescence in situ hybridization (FISH) of the relationship between gonosomic aneuploidy and the results of assisted reproduction in men with severe oligozoospermia.

The aim of this study was to analyse the frequency of sex-chromosomal aneuploidy in human spermatozoa of severe oligozoospermic men undergoing intracytoplasmic sperm injection (ICSI), to evaluate the impact of these chromosomal anomalies on the results of the ICSI. Fluorescence in situ hybridization (FISH) with direct label fluorescence DNA probes specific for chromosome X, Y and 18 was performed on decondensed spermatozoa from fresh ejaculates of 12 patients with severe oligozoospermia undergoing ICSI. A total of 500 spermatozoa were analysed per donor. The rate of gonosomal aneuploidy was significantly increased in the patients compared with normal donors (3.5% and 0.8% respectively). The sex-chromosomal anomalies due to meiosis I (XY) are less important than the anomalies caused by meiosis II (XX or XY), but the difference was not statistically significant. There was a negative correlation between the rate of aneuploidy and the percentage of spermatozoa with normal morphology (r = -0.71; P < 0.05). The correlation was negative between the percentage of gonosomic aneuploidy and the rate of fertilization (r = -0.7; P < 0.001). Our results suggest an increased rate of gonosomic aneuploidy in the patients with oligozoospermia compared with the normal population. This aneuploidy, although it decreases the rate of fertilization, does not seem to affect the rate of cleavage, nor the embryonic quality.

Abortion, Spontaneous↗
PubMed2004

Selection bias in semen studies due to self-selection of volunteers.

BACKGROUND: Reports of a secular decrease in semen quality remain controversial, particularly due to the possibility of selection bias. We aimed to describe the potential bias due to self-selection of volunteers in semen studies involving fecund men. METHODS: Using data from the French multicentre study REPRHOM, we compared the characteristics of the partners of pregnant women for three levels of participation: completion of a refusal questionnaire (n = 698), agreement to complete the study questionnaires only (n = 676) and agreement to complete the study questionnaires and give a semen sample (n = 331, 13% of the subjects approached). RESULTS: Poorly educated men refused more often to participate than highly educated men. Semen providers were more likely to have experienced unfavourable pregnancy outcomes (odds ratio 1.68, 95% confidence interval 1.14-2.49) compared with participants completing the questionnaires only. Time to pregnancy was similar for all participants. CONCLUSIONS: This study demonstrates the existence of selection bias in semen studies associated with fertility and socio-demographic characteristics of men. The results of semen analysis for this population sample cannot be extrapolated to the whole population from which the volunteers originate. More information is required on who participates, and participation rates should be reported in semen studies to make it possible to interpret the results correctly.

Adult↗
PubMed2002

Pregnancy after safe IVF with hepatitis C virus RNA-positive sperm.

In France, assisted reproductive technology (ART) for hepatitis C virus (HCV)-infected patients is now subject to strict control after the publication of recent guidelines. Infertile serodiscordant couples (HCV-viraemic men and their seronegative female partners) require special care to carried out in designated 'viral risk' laboratories. Twelve sequential semen samples taken from an HCV chronically infected patient were analysed within 22 months. HCV RNA was detected in all the seminal plasma sampled before antiviral treatment with relatively high viral loads, and in two of the corresponding fractions of motile sperm obtained after a gradient selection, suggesting that a contamination risk by HCV through ART cannot be excluded. When the selection of sperm on a discontinuous gradient was followed by an additional swim-up step, HCV RNA was never detected in the motile sperm suspension that was frozen in highly secure straws. IVF was performed using cryopreserved sperm that tested negative for HCV RNA, resulting in a pregnancy. One month after embryo transfer, testing for HCV RNA and antibodies in the woman gave negative results.

Adult↗
PubMed2001

Follicular viability and morphology of sheep ovaries after exposure to cryoprotectant and cryopreservation with different freezing protocols.

OBJECTIVE: To test the toxicity of cryoprotectant in sheep ovarian tissue and to determine optimal conditions for freezing hemiovary cortex. DESIGN: Small follicles (<60 microm in diameter) were isolated enzymatically for viability testing. Dead and live follicles were identified by using trypan blue staining, and follicle morphology was examined histologically. SETTING: Centre hospitalo-universitaire de Biologie de la Reproduction, Hôpital Edouard Herriot, Lyon, France. ANIMAL(S): Lambs 5 to 6 months of age. INTERVENTION(S): Two-millimeter slices of hemiovarian cortex were prepared for cryoprotectant toxicity tests and freezing procedures. MAIN OUTCOME MEASURE(S): Follicular mortality and histologic structure. RESULT(S): For freezing procedures, the concentration of cryoprotectant was increased to 2 M on the basis of results of cryoprotectant toxicity tests in fresh tissues. Follicular mortality rates were 4.6% with of 2 M dimethyl sulfoxide (DMSO) and 3.8% with 2 M of propylene glycol (PROH). After freezing with semiautomatic seeding, follicular mortality rates were 8.4% (2 M of DMSO) and 12.4% (2 M of PROH). Tissue morphology was well preserved with 1.5 M of DMSO or PROH. With 1.5 M DMSO, results of the slow cooling protocol (2 degrees C/min) without seeding and the standard very slow cooling protocol (0.3 degrees C/min) were similar. CONCLUSION(S): Optimal survival of primordial follicles in the sheep was obtained by using a slow cooling protocol with semiautomatic seeding at 2 M of DMSO.

Animals↗
PubMed2001

Gonadotropin level abnormalities in women with cyclic mastalgia.

OBJECTIVES: Women with cyclic mastalgia seem to be at risk of fibrocystic breast disease and/or breast cancer. We studied the relationships between mastalgia and hormone levels throughout the menstrual cycle. STUDY DESIGN: Ostensibly healthy women were monitored during a sum of 326 cycles. A case-control study compared personal and hormonal variables of 30 women experiencing cyclic mastalgia with those of 77 women without this symptom. RESULTS: Except sleeping times, no significant differences were found in personal variables. Cyclic mastalgia and symptoms of fluid retention were slightly associated. Menses and the luteal phase were significantly longer in cases than in controls. Gonadotropin but not ovarian hormone levels were also significantly higher in cases throughout the cycle. CONCLUSION: Cyclic mastalgia is less related to symptoms of fluid retention or to ovarian hormone levels than to regularly high gonadotropin levels, specific inhibitors might thus be used to alleviate the symptom.

Adult↗
PubMed2001

Apoptosis in preimplantation mammalian embryo and genetics.

The presence of dead cells in the preimplantation mammalian embryo has been well described. Since Kerr et al. (1972), it has become apparent that these cells die by apoptosis, a form of programmed cell death. This review analyses the recent morphological and biochemical evidence that apoptosis play a role in early mammalian embryo development. Normal and apoptotic (i.e. fragmented) embryos express several apoptosis-related genes during mammalian preimplantation embryo development, with severe changes when apoptosis is activated; these findings support a model in which mammalian preimplantation embryo development is regulated by the ratio of pro- and -anti- apoptotic genes. Apoptosis may be a normal feature in human preimplantation development, even in vivo, and may play an active role in the developing embryo through the removal of genetically abnormal cells. Contrary to these beneficial effects, apoptosis may have detrimental effects if either the number of apoptotic cells or ratio of these cells to the normal cells is elevated. According to this value, embryos could either continue to develop or arrest.

Animals↗
PubMed2000

Cyclodextrin enhances spermicidal effects of magainin-2-amide.

Magainins are antimicrobial peptides with known spermicidal activity. Their activity is inhibited by cholesterol present in eukaryotic cell membranes. Pretreatment of spermatozoa with methyl-beta-cyclodextrin, which extracts cholesterol from cell membranes and induces capacitation, sensitizes them to magainin-2-amide as shown by a decrease in human sperm motility determined by computer-assisted sperm analysis and a concomitant decrease in sperm viability, as measured by MitoTracker(R) Red CMXRos labeling. Magainin-2-amide affects mainly the fast progressive spermatozoa inducing them directly into an immotile state, without an increase in motile non-progressive and slow progressive spermatozoa. We conclude that methyl-beta-cyclodextrin highly potentiates the deleterious effect of magainin-2-amide on human spermatozoa. Most probably, this effect can be explained by cholesterol extraction from sperm cell membranes.

Animals↗
PubMed2000

Proteasomes in human spermatozoa.

In the present study we describe the localization of proteasomes in human spermatozoa by means of immunolabelling with different monoclonal and polyclonal antibodies detected by confocal microscopy. Western blotting confirmed the specificity of the antibodies and has shown that proteasomes are present in spermatozoa and in seminal fluid. In spermatozoa proteasomes are concentrated in the neck region where the centrioles are located. Some labelling was also detected at the periphery of the head, but no proteasomal antigens were detected in either the nucleus or associated with the flagellum. Proteasome inhibitors did not affect the motility of the spermatozoa, acrosome reaction nor zona binding. It is hypothesized that paternal proteasomes enter the oocyte during fertilization in tight association with the centrioles and may serve a special function during further development which can be associated with the function of a hypothetical proteolysis centre.

Blotting, Western↗
PubMed2000

Transmission risk of hepatitis C virus in assisted reproductive techniques.

Medical assistance for procreation in a couple where one or both parents has hepatitis C viral infection (HCV) raises the issue of the transmission of the infection to the baby and/or of possible contamination of both the technicians and the gametes or embryos from virus-free parents in the laboratory. It becomes essential to assess transmission risk in assisted reproductive techniques in order to define clearly the management of couples according to their viral status. To define the HCV transmissibility risk in assisted reproduction related to the presence of virus in semen from infected infertile men, HCV RNA detection was performed in sera, and semen and sperm fractions obtained after Percoll gradient centrifugation. HCV RNA was detected in 5% (2/39) of the semen samples tested: in the raw semen, in the seminal fluid and in the cell pellet but never after Percoll selection. According to these results, we suggest a strategy for HCV-infected infertile men who need assistance for procreation.

Adult↗
PubMed2000

Localization of proteasomes in human oocytes and preimplantation embryos.

In the present study we describe the localization of proteasomes in human oocytes, apoptotic preimplantation embryos, and triploid preimplantation embryos by means of immunolabelling with the MCP21 monoclonal antibody detected by confocal microscopy. While in the oocytes proteasomes are scattered throughout the cytoplasm, in the pronuclear zygote they appear to concentrate at the periphery of the cytoplasm and do not enter the pronuclei. During early cleavage stages, proteasome immunolabelling is concentrated in the nuclei, while the examination of triploid blastocysts showed that proteasomes had a similar cellular distribution to somatic cell lines, i.e. in the nuclei but not in the nucleoli or the cytoplasm. It appears that the distribution of proteasomes dramatically changes during human preimplantation embryo development.

Cysteine Endopeptidases↗
PubMed1999

Restoration of ovarian steroid secretion and histologic assessment after freezing, thawing, and autograft of a hemi-ovary in sheep.

OBJECTIVE: To evaluate the effects of freezing, thawing, and autograft of a hemi-ovary on steroid secretion, endometrial maturation, and ovarian histology in ewes. DESIGN: Experimental animal study. SETTING: Laboratoire de Zootechnie, Ecole Nationale Vétérinaire, Marcy l'Etoile, France. ANIMAL(S): Six lambs aged 6 months to 1 year old. INTERVENTION(S): Hemi-ovaries were prepared and frozen from the right ovary of six lambs and autografted 4 weeks later to the contralateral ovarian hilus. The autografts and the uterus were recovered 1 year later. Blood tests were performed each week to measure P concentration. MAIN OUTCOME MEASURE(S): Number of primordial follicles; levels of plasma P. RESULT(S): Histologic examination of ovarian slices after freezing showed no destruction of primordial, primary, secondary, or cavitary follicles. The frozen ovarian autograft showed good recovery of the macroscopic and microscopic ovarian structure. After autografting, histologic examination revealed primordial to cavitary follicles. Secretion of P started to rise 4 weeks after the autograft. Histologic analysis of the endometrium showed numerous glands, vessels, and mucous secretion. CONCLUSION(S): Frozen ovarian autografts achieved P secretion and endometrial maturity.

Animals↗
PubMed1998

Freezing, thawing, and autograft of ovarian fragments in sheep: preliminary experiments and histologic assessment.

OBJECTIVE: To evaluate the effects of freezing and thawing on the histologic changes in ovarian fragments from sheep and to determine the feasibility of ovarian autografts. DESIGN: Histologic evaluation of follicles that survived after freezing at -196 degrees C for 2 weeks. Histologic evaluation of ovarian fragments 6 months after the autografts. SETTING: Laboratoire de Zootechnie, Ecole National Véterinaire, Marcy l'Etoile, France. ANIMAL(S): Six ewes aged 6 months to 1 year. INTERVENTION(S): Cortical fragments were prepared from the right ovary of 6 lambs and were grafted immediately to the contralateral ovarian hilus or were cooled slowly to -196 degrees C in medium containing dimethyl sulfoxide for 2 weeks. The autografts were recovered 6 months later. RESULT(S): Histologic examination of ovarian slices after freezing showed no destruction of primordial, primary, secondary, or cavitary follicles. The ovarian autograft showed good recovery of the macroscopic and microscopic ovarian structure. After autografting, histologic examination revealed primordial to cavitary follicles. CONCLUSION(S): Freezing of ovarian fragments is possible without damaging the follicles. Ovarian autografts showed good recovery of ovarian structure.

Animals↗
PubMed1998

Laser scanning confocal imaging of abnormal or arrested human preimplantation embryos.

PURPOSE: The improved resolution and optical sectioning of a confocal microscope make it an ideal instrument for extracting three-dimensional information, especially from extended biological specimens such as human embryos. The staining of actin together with chromatin allowed us to specify the architecture of the embryo and the appearance of the nucleus. METHODS: F-Actin and chromatin distributions were visualized using laser scanning confocal microscopy in "fresh" and "cryopreserved" human preimplantation embryos obtained by in vitro fertilization. RESULTS: The current study revealed a high rate of multinucleation in arrested or poor-quality embryos (89%, in grade IV embryos). CONCLUSIONS: Confocal microscopy revealed high levels of multinucleated blastomeres, suggesting that the probable cause of arrested development in these embryos was due to multinucleation of blastomeres.

4-Chloro-7-nitrobenzofurazan↗
PubMed1998

Annexin V labelling and terminal transferase-mediated DNA end labelling (TUNEL) assay in human arrested embryos.

Confocal laser scanning microscopy was used to observe human arrested and fragmented preimplantation embryos obtained by in-vitro fertilization. Observation of the cellular actin cortex and chromatin showed a high frequency of embryos with blastomeres exhibiting two or more nuclei, while others had nuclei displaying chromatin condensation and fragmentation patterns. Many of the abnormal chromatin images could be due to the process of programmed cell death (apoptosis). The possible link between abnormalities of the blastomeres and apoptosis was investigated using two detection methods for cells undergoing apoptosis. Detection of phosphatidylserine exposure was performed using annexin V; the chromosomal breakdown preceding the nuclear collapse of apoptotic nuclei was tested using the terminal transferase-mediated DNA end labelling (TUNEL) assay. Annexin V staining was observed in all arrested and/or fragmented human embryos, but not in cryopreserved embryos which continued to develop normally after thawing. The TUNEL assay was positive in 30% (15/50) of arrested embryos, all of which had cytoplasmic fragments. In contrast, embryos showing regular size blastomeres without fragments were TUNEL negative.

Actins↗
PubMed1997

Detection of cytomegalovirus in semen from a population of men seeking infertility evaluation.

OBJECTIVE: To determine the incidence of cytomegalovirus in the ejaculates of infertile men who were seropositive for IgG antibodies to cytomegalovirus. DESIGN: Prospective study. PATIENT(S): We tested cytomegalovirus infection in the semen of men participating in an IVF-ET program. MAIN OUTCOME MEASURE(S): IgG and IgM antibodies to cytomegalovirus were measured in sera. We used polymerase chain reaction (PCR) and cell culture to look for both cytomegalovirus DNA and infectious virus in the semen of 70 men with cytomegalovirus-specific antibodies detected in sera. RESULT(S): Of the infertile couples, 13.5% exhibited "mismatching" serology (i.e., detection of IgG antibodies to cytomegalovirus in male serum only and not in female serum) and constituted a potential risk for cytomegalovirus transmission. Cytomegalovrius was identified in the semen of two patients who were positive for IgG antibodies to cytomegalovirus. Cytomegalovirus DNA also was detected in one positive sample after centrifugation through a three-layer Percoll gradient. CONCLUSION(S): Human cytomegalovirus was present in the semen from a population of infertile men. Rapid detection can be achieved by molecular techniques such as PCR combined with a hybridization assay. Even though cytomegalovirus was infrequently detected in semen, these data must be considered in determining the risk of transmission and developmental anomalies in infected fetuses.

Adult↗
PubMed1997

Interest of co-cultures for embryos obtained by in-vitro fertilization: a French collaborative study.

Co-cultures of human embryos, particularly with Vero cells, are used by several French groups, mainly in cases of successive failures of implantation. In most cases co-culture is continued until the blastocyst stage, expanded if possible. A total of 1603 co-cultures have been performed by 11 groups over a 2-year period. Of these, 41.8% of cleaved eggs (day 2) reached the blastocyst stage at day 5 or day 6. The mean pregnancy rate and implantation rate per transfer were 32.9 and 24.8% respectively, which represented a significant improvement compared to the transfer of 2 day old embryos. The rate of multiple pregnancies remained high (29.1%), which implies that there should be transfer of not more than two blastocysts. The rate of anomalies perceived at birth or in utero was not different from the rate observed in the general population, taking account of the maternal age.

Adult↗
PubMed1997

Influence of co-culture with established human endometrial epithelial and stromal cell lines on sperm movement characteristics.

The effects of co-culture of human spermatozoa with human immortalized endometrial cells - epithelial or stromal - on sperm movement characteristics, including hyperactivation, were studied using computer-assisted sperm analysis (CASA). Epithelial and stromal cell types could be separated following 8-10 days of culture of endometrial cells originating from human biopsies. Both cell types were immortalized by the SV 40 large T antigen. Co-incubation of sperm with epithelial and stromal monolayers enhanced the rate of hyperactivation: 24.9% (P <0.05) and 17.8% (P = 0.05) versus 9.5% as control, respectively, whereas the majority of motility parameters remained unchanged. Conditioned media had no effect upon sperm parameters, including hyperactivation. Co-incubation with either monolayer was able to maintain sperm motility over a longer period than incubation in control medium alone. In four patients whose spermatozoa did not exhibit hyperactivation, co-incubation with epithelial cells, but not conditioned medium, allowed normal rates of hyperactivation (range: 6.9-15.6%).

Antigens, Polyomavirus Transforming↗