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Biomedical subjects

M Plachot

Publications and source records attributed to M Plachot.

At least 127 records · Page 7Linked to original sources
PubMed1982

[Evaluation of the fertility of human sperm by interspecies (man-hamster) in vitro fertilization].

An "in vitro" fertilization test employing zona-free hamster eggs was used to analyse human spermatozoal fertilizing ability. Sperms from 28 men (group 1) whose wives were candidates for "in vitro" fertilization and embryo transfer, and from 5 men belonging to infertile couples (group 2), were evaluated for their ability to penetrate and decondense in zona-free hamster ova. All men had spermiograms in the normal range. A total of 529 eggs were inseminated with spermatozoa from group 1 and the fertilization rate was found to range from 8% to 100% with an average of 57.5%. Of the 130 ova tested with sperm from group 2 individuals, only one showed any evidence of penetration. The fertilization rate and the degree of polyspermy failed to show a significant correlation with sperm concentration in the ejaculate or motility. This cross-species system is a useful additional test to the classic spermiogram and may have a potential value as a diagnostic tool in evaluating human spermatozoal fertilizing capacity, avoiding the ethical and logistical problems associated with fertilization of human eggs "in vitro".

Animals↗
PubMed1980

[Maturation and in vitro fertilisation of human oocytes recovered after spontaneous ovulation or after induction of ovulation by use of gonadotrophins (preliminary results) (author's transl)].

Maturation and/or in vitro fertilisation of human oocytes was carried out on 70 oocytes recovered from 56 young women who had normal periods and were having laparoscopy for tubal sterility. Five oocytes were recovered in the pre-ovulatory phase of spontaneous cycles by the use of ultrasound determination of follicular growth and the presence of an LH peak estimated from urine levels. 65 oocytes were obtained by puncture of follicules that had been stimulated using HMG/HCG 32-36 hours after HCG had been injected. 66 per cent of these eggs showed signs of degeneration before culture. The immature oocytes which were cultured for 42-46 hours at 36 degrees C with or without gonadotrophins underwent meoisis in 80 per cent of cases and 41 per cent expelled their first polar body. None of these oocytes could be fertilised in vitro, whereas 50 per cent of the oocytes that were recovered in metaphase II and fertilised in vitro had reached the stage of pronuclei 20 hours later. Ultrastructural and cytogenic studies will be carried out to ascertain the quality of these eggs before any attempt is made to reimplant.

Adult↗
PubMed1978

[Anomaly of the nuclear maturation in vitro of golden hamster oocytes].

Nuclear anomalies were observed during maturation in vitro of golden hamster oocytes, as follows: 1) In 33 p. cent of oocytes, the axis of the first meiotic division spindle was oriented incorrectly. This leads either to the formation of "large" polar bodies or to non-expulsion of the polar body if the spindle occupied a central instead of peripherical position. 2) Triploidy was observed in 0.3 p. cent of the oocytes which accomplished their maturation and fertilization in vitro. 3) Two rare anomalies--reconstitution of the nucleus after expulsion of the first polar body and formation of two second division spindles--appeared to be due to degenerescence of the oocytes in culture.

Animals↗
PubMed1977

[Infertility of the hamster oocyte having matured in vitro].

The comparative study of fertilization, with the same sperm sample, of in vitro matured oocytes and freshly ovulated ones, shows a new aspect of mammalian oocyte maturation. While 80% of freshly ovulated oocytes are fertilized, in vitro matured eggs are not fertilizable. They present the ability to be penetrated by spermatozoa 4 to 6 hrs. only after HCG injection. This is therefore not on tubal influence but depends on an oocyte specific factor which appears during the end of intrafollicular maturation.

Animals↗
PubMed1975

[Estroprogestational drugs and the ultimate embyogenesis in the rat].

Cyclic female rats were fed with ethinodiol diacetate plus mestranol (EDM) for periods of 45 to 180 days. They were mated during prooestrus, on the first cycle following the end of the treatment. Results were as follows: 1. The cycle is blocked about eight days after starting E.D.M. The longer the treatment, the later rats resume their cycle. 2. Degeneration of the ova before implantation and embryonic mortality are slightly augmented when fecundation takes place within two days after stopping E.D.M.; whereas from the third cycle on, the quality of th ova is identical to the control group. The ova are euploid; they are more fragile to hypotonic shock than the ova of the control animals. No influence of E.D.M. upon meiotic or mitotic processes could be demonstrated. Those experiments do no allow any inference to the human species, but they are inkeeping with the observations of Boué et al. on women.

Animals↗
PubMedDate not supplied

[Chromosome abnormalities in male sterility].

A study of the caryotype in 281 cases of male secretory sterility. Chromosomal anomalies were found in 81 cases, i.e. 78 cases, of azoospermia, 3 cases of oligospermia. Barr bodies were found in 66 cases of Klinefelter syndrome or one of its varieties. In the remaining 15 cases, there was no Barr chromatin: 7 of them bore gonosomal abnormalities with or without mosaicism. In 8 cases reciprocal translocations were found: in 2 of them a sexual chromosome was involved. The high rate of chromosomal anomalies should be stressed: every male secretory sterility, especially with azoospermia, warrants a chromosomal study. In the group of translocations, FSH and LH rates are not elevated in spite of the existence of azoospermia, whereas they are consistently increased in all the other chromosomal abnormalities: this so far undescribed phenomenon has no present explanation. The role played by translocations in male secretory sterility, although difficult to understand, is well documented, since translocations occur ten times more frequently in male sterility than in the general population.

Chromosome Aberrations↗
PubMedDate not supplied

Gamete quality in human in vitro fertilization.

The success of in vitro fertilization and embryo transfer depends mainly on oocyte and sperm quality. As far as the oocyte is concerned, its fertilizability and capacity for subsequent development are related to intrinsic factors: quality and maturity, and extrinsic factors; quality of superovulation monitoring. These parameters have been widely studied using morphological (appearance of the oocyte-cumulus complex) and endocrine (plasma and follicular hormonology) criteria.

Cells, Cultured↗
PubMedDate not supplied

Evaluation of human sperm fertility by interspecific (human spermatozoa-hamster oocytes) in vitro fertilization.

The fertilizing capacity of 1) Males with unproven fertility to be admitted to an IVF/RE programme; 2) Probably infertile subjects and of 3) Males with idiopathic infertility, has been evaluated using the humster (HUMan-hamSTER) test. Sixty-seven percent of normal sperms from the IVF-Re couples were capable of fertilizing hamster oocytes, with an average fertilization rate of 52%. In one of the suspect male infertility group sperms were able to fertilize hamster oocytes and in the idiopathic infertility group forty-eight percent of sperms fertilize, but the average fertilization rate is clearly lower. It is surprising that 26% of normal sperms have a negative humster test and fertilize the human oocytes at the same rates (86%) as those having a positive humster test. It means that if statistically and over large populations this test undoubtedly gives good results, when the individual cases are taken into consideration this test does not provide final proof of the patient's infertility. Nevertheless the authors stress that the test may provide a new criterion for determining sperm quality and in the future it might become a complementary examination of the spermogram and postcoital test and supply fundamental data on the mechanism of fertilization (capacitation, acrosome reaction, spermatozoa-oocyte fusion and pronuclei formation).

Animals↗
PubMedDate not supplied

[Oocyte maturity and quality: value of intracytoplasmic sperm injection. Fertility of microinjected oocytes after in vitro maturation].

Many studies in IVF practice, have tried to assess the maturity and quality of oocytes prior to insemination and relate it to IVF efficiency and to the pattern of ovarian stimulation. They were based on the indirect evaluation of the aspect of the cumulus-corona-cell complex (CCC) which was rapidly shown to be poorly correlated to the oocyte nuclear and cytoplasmic maturity in stimulated cycles. For sperm microinjection procedures, oocytes need to be peeled off from any follicular cell through hyaluronidase action in order to gain an easy access to the zona pellucida and the ooplasm. If therefore becomes possible to precisely known at recovery the nuclear status of the oocyte cohort as well as the rate of degenerative gametes. Immature oocytes can be further matured in vitro. Moreover, the ICSI procedure (intracytoplasmic sperm injection) allows a direct assessment of the cytoplasmic maturation, whatever the maturity of the ZP and its receptors and of the plasma membrane. On a preliminary evaluation of 70 ICSI cycles performed in our collaborative group from september to november 1994 and leading to a 24 % pregnancy rate per oocyte pick-up we focused on the true maturation of the oocyte cohort, its outcome and correlation with ICSI efficiency and stimulation protocol. On the 760 oocytes, 13.9% were atretic, 9% at the germinal vesicle stage (GV), 3.4% in metaphase 1 and 73.7% in metaphase 2 at recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Indications for intracytoplasmic sperm injection: possible influence of oocyte quality on the results].

Intracytoplasmic sperm injection is theoretically the first line treatment of many forms of severe male infertility, but the prognostic factors are to be determined according to the indications. Thus the results of two clinical teams working with the same biological Unit show statistically different pregnancy rates per oocyte pick-up (15.9% versus 35.7% - p < 0.02) and per transfer (16.9% versus 34.9% - p < 0.03). They could by explained by female factors such as age and ovarian response to stimulation, which probably have influence on embryonic quality.

Cytoplasm↗
PubMedDate not supplied

[Fertility tests (hamster, electronic microscopy): are they useful?].

Tests of sperm function are often considered to be able to predict the in vivo or in vitro fertility of a given patient although they only assess part of the process of sperm fertilizing ability. It appears from the literature, that the sperm penetration assay (SPA) which investigates the sperm fusiogenic and nuclear functions cannot accurately predict the in vivo fertility and there is still much debate on the reliability of its correlation with in vitro fertilization (IVF) principally in cases of severe sperm deficiency. With the development of new techniques of assisted fertilization, by-passing the zona pellucida, a test of sperm fusion, hetero or homospecific as well, could be interesting. Considering sperm ultrastructure and beyond some specific morphological alterations of the whole sperm population that can be responsible for the infertility, such studies were not able, as yet, to reveal significative differences between semen fertile in vitro or not.

Animals↗
PubMedDate not supplied

[Oocyte maturation and intracytoplasmic sperm injection].

Intracytoplasmic sperm injection (ICSI), treatment of severe male infertility allows an accurate evaluation of oocyte maturity at recovery after corona-cell removal. In cycles comprising a GnRH analog desensitization and a stimulation by hMG or FSH, 12% of oocytes aspirated from follicles (> 14 mm), 34 hours post-hCG are still immature, in prophase or metaphase 1. They are able to achieve meiosis in vitro in 66% of the cases and will be fertilized (2 PN) by ICSI in 51% of the cases as the in vivo mature oocytes of the same cohort. Nevertheless, the quality of cytoplasmic maturation and consequently of embryonic viability remains to be assessed as there still are few pregnancies arising from in vitro matured oocytes. ICSI also represents the only way to obtain normal fertilization in some exceptional but observed anomalies of oocyte maturation, particularly when there is a lack of zona reaction leading to repetitive polyspermy in conventional IVF.

Adult↗