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M O Alnot

Publications and source records attributed to M O Alnot.

At least 19 recordsLinked to original sources
PubMed1999

French Machado-Joseph disease patients do not exhibit gametic segregation distortion: a sperm typing analysis.

Segregation distortion has been reported to occur in a number of the trinucleotide repeat disorders. On the basis of a sperm typing study performed in patients of Japanese descent with Machado-Joseph disease (MJD), it was reported that disease alleles are preferentially transmitted during meiosis. We performed a sperm typing study of five MJD patients of French descent and analysis of the pooled data shows a ratio of mutant to normal alleles of 379:436 (46.5:53.5%), which does not support meiotic segregation distortion. To confirm these results, sperm typing analysis was also performed using a polymorphic marker, D14S1050, closely linked to the MJD1 gene. Among 910 sperm analyzed, the allele linked to the disease chromosome was detected in 50.3% of the samples and the allele linked to the normal chromosome was found in 49.6% of the sperm. The difference in frequency of these two alleles is not significant ( P = 0.8423). Likelihood-based analysis of segregation distortion in the single sperm data using the SPERMSEG program also showed no support for segregation distortion at the gamete level in this patient population. The previous report on the Japanese patients also suggested that disease allele stability may be influenced by a trans effect of an intragenic polymorphism (987 G/C) in the wild-type allele. All of the French patients were heterozygous for this polymorphism. However, analysis of the variance in repeat number in sperm from the French MJD patients overlapped significantly with the variance in repeat number observed in the C/C homozygous Japanese patients.

Alleles↗
PubMed1998

Cryopreservation in human assisted reproduction is now routine for embryos but remains a research procedure for oocytes.

Human embryo cryopreservation represents an indispensable extension of in-vitro fertilization (IVF) programmes as long as they are based upon the recovery of a large number of oocytes. The most widely used procedures include the cryopreservation of human zygotes or embryos in early cleavage, using 1,2-propanediol and sucrose as cryoprotectants. Our results over a 10 year period (1986-1995) on 5032 thawed cycles involving 14 222 stored embryos make it possible to appraise the results and the contribution of embryo freezing to assisted reproduction. Embryos survived the freeze-thaw process in 73% of cases leading to 4590 transfers of 2.2 embryos (91% of thawed cycles). The clinical pregnancy rate per transfer was 16%, the live birth rate 12%, and the rate of babies born alive per transferred embryo was 6%. Embryo freezing monitored 10 years later produced an average of 8% of additional births. By then, 86% of stored embryos had been thawed for transfer to patients. Destruction or donation were required for only 8% of all frozen embryos and there was no news from the parental couple in relation to almost 6% of embryos. The fate of the vast majority of embryos was decided during the first 5 years of storage. Blastocyst cryopreservation is making new strides, thanks to co-culture systems and embryo selection. Micromanipulation procedures seem to have little impact on the outcome of embryo freezing. Human oocyte freezing is again clinically applied. Indeed, much of the concern about injuries to the oocyte structures through the freeze-thaw process do not seem to be justified, and the problems with frozen-thawed oocyte fertilization has been overcome using intracytoplasmic sperm injection (ICSI). As long as oocyte in-vitro maturation is not well controlled, better results will probably be obtained with mature oocyte cryopreservation. Emerging methods include the freezing of immature oocytes, follicles and ovarian tissue.

Cryopreservation↗
PubMed1996

[Cryopreservation of human embryos after in vitro fertilization: immediate and long-term results].

Between 1990 and 1994, a clinical retrospective study has been carried out at Tenon Hospital on 1200 patients: during this periods. 4845 embryos have been cryopreserved and 31% of the patients had this procedure for their supranumerary embryos. The rate of implantation by embryo was 8% per transfer, comparable to those fresh embryos. Less than 1% of the embryos were abandoned. The contribution of cryopreservation to the IVF program is substantial, increasing pregnancy rate by 10%. Moreover, the rate of multiples pregnancies is significantly lower when implanting frozen thawed embryos (9.6%) vs fresh embryos (p < 0.001). There was no difference between frozen-thawed and fresh embryos, in the implantation rate by embryo, the mean gestational age, and birth weight of singleton, twin and triplet births. From a biological point de vue, a series of 3693 embryos, carried on the same period, in our center has showed that for the success of this procedure, the quality of the embryos was more important, than the duration of the storage. The incidence of major and minor congenital malformations was not different in the two groups of babies (less than 3%). But a retrospective analysis carried out on 84 children, showed 4 major abnormalities, after a follow up of 1 to 9 years. However these anomalies do not seem to have some evident correlation with the cryopreservation procedure; a larger series and a prospective study are needed to get significant results concerning the health of the children born after the procedure of cryopreserved embryos.

Birth Weight↗
PubMed1996

[Oocyte donation -- embryo donation].

From 1993 to 1995, 82 donors have permitted the retrieval of 810 oocytes allowing to obtain 411 embryos. 95 receiving couples have been included : 30 obtained a pregnancy, 7 abandoned and 38 are waiting for a transfer. The rate of pregnancies by transfer is superior to the one observed with the transfer of frozen embryos (40.5% versus 27%).

Adult↗
PubMed1993

[1992 results of sperm donor procreation. French Federation of CECOS and private cooperative centers].

In 1992, the results record the referred activity of French Federation of CECOS and IFREARES-Toulouse. 6,714 patients underwent donor inseminations for one or more cycles, 20,525 cycles were undertaken resulting in 2,234 pregnancies using AID or IVF. 606 volunteers men come forwards as donors. The analysis of 1,777 deliveries resulting of recoveries realised in 1991, showed with IVF a high rate for twins and multiple births. The activity of semen preservation and embryo's storage is always increasing. The wishes about the parentless outcome embryos is performed.

Clinical Protocols↗
PubMed1993

[In defense of intra-uterine inseminations].

Intrauterine insemination (IUI) has been used for treatment of infertility for many years with discouraging results (8.3% in the analysis of Dorangeon and Quereux). A new approach of IUI, using ovarian stimulation, ovulation monitoring and sperm preparation has significantly improved the results. The obtained pregnancy rate (15 to 25%) are now comparable to those reported with IVF or GIFT. Therefore IUI should be offered to patients with patent tubes prior to their referral for the more invasive procedure FIV or GIFT.

Clinical Trials as Topic↗
PubMed1990

[Methods for studying the sperm fertilizing capacity].

Spermatozoa achieve their fertilizing capacity through numerous biocellular changes occurring in male and female genital tracts. From testicular production to male pronucleus formation, the aim of this study is to point out the various laboratory techniques which have been developed to assay semen fertilizing capacity. Most assessments only investigate one of the aspects of sperm fertilizing ability, IVF only can appraise the whole process.

Female↗
PubMed1988

Cryopreservation of human embryos and oocytes.

The success rate of human embryo cryopreservation depends on technical and embryonic parameters. First of all, the cryoprotectant can affect embryo survival as we found by comparing two freeze-thaw procedures using propanediol (PROH) (1.5 mol) alone or with sucrose (0.1 mol). Embryo survival was significantly enhanced with sucrose (62 versus 32%). Embryo quality is another major parameter involved in the success of freezing; the rates of positive survival were found to be 67% for morphologically normal embryos versus 49% for embryos with fragments (P less than 0.001). The efficiency of embryo cryopreservation in an IVF programme could be estimated in 1986: a woman with extra embryos, stored after transfer of 3-4 fresh embryos (16% of all cycles), can expect a 22% pregnancy rate per transfer of fresh embryos and a 32% pregnancy rate per collection after transfer of the stored eggs. A comparative study of the cryopreservability of immature or mature oocytes was performed in humans. Human oocytes have a low survival rate (36%) whatever the cryopreservation protocol or the initial maturation stage. Immature human oocytes could survive freezing and thawing, mature and be fertilized in vitro, but with a very low efficiency.

Embryo Transfer↗
PubMed1988

Anonymous and non-anonymous oocyte donation preliminary results.

During the past year, we have developed an oocyte donation programme in 10 patients with complete absence of endogenous ovarian function (premature ovarian failure in seven cases, castration in two cases and Turner's syndrome in one case). In cases of anonymous donation, donors were volunteers devoid of any major genetical risk who were included in our IVF programme and who consented to donate one oocyte when at least seven oocytes were recovered, and two oocytes when at least 11 oocytes were recovered, to a recipient couple. As far as possible, morphological characteristics of both couples were paired. In cases of non-anonymous donation, donors were 'affective' donors, having at least one child. The resulting embryos after IVF of donated oocytes were either replaced directly in recipient women which required synchronization of the donor's and recipient's cycles, or cryopreserved and then thawed, usually at day 16 of recipient's artificial cycle, i.e. 2 days after introduction of the progestational compound. On the 10 patients entering this oocyte donation programme (20 cycles), 13 transfers were carried out resulting in four clinical pregnancies in three patients with premature ovarian failure and one with Turner's syndrome (20% pregnancy per cycle and 31% per transfer). Despite the small numbers, these good results prompted us to develop this protocol.

Adult↗
PubMed1987

Human embryo cryopreservation, extrinsic and intrinsic parameters of success.

Freezing and thawing (F - T) was applied to 490 early human embryos using propanediol as cryoprotectant. The survival rate of embryos frozen with propanediol alone did not exceed 31% (26/83). The combination of propanediol and sucrose, however, significantly increased the percentage of surviving (248/407 = 61%) and intact (188/407 = 46%) embryos and seemed to enhance embryo viability as suggested by the implantation rate (14.5 versus 8%) without, however, any statistical significance. Embryo survival, but not viability, was correlated with morphological features, whereas neither the age of embryos (1, 2 or 3 days post-insemination) nor the segmentation stage (regular or intermediate) were involved in F - T ability. Thirty-eight F - T embryos implanted when replaced in utero, representing 8% of all F - T embryos and 14% of the F - T replaced embryos. The pregnancy rate per transfer reached 19% (35/185) and was identical to the pregnancy rate per transfer of fresh embryos (253/1149 = 22%). In oocyte donation, too, embryo freezing did not impair the pregnancy rate (25%). In spontaneous cycles, synchronous transfer gave better results than asynchronous transfers (20 versus 10%), but spontaneous cycles had no significant advantage (16% pregnancy/transfer) as compared to stimulated (26%) and artificial (27%) cycles.

Blastomeres↗
PubMedDate not supplied

[Evolution of the practice of sperm cryopreservation and fate of the preserved specimens : retrospective study of testicular cancer].

Testis cancer, chemotherapy and radiation can induce temporary or permanent infertility in men. Cryopreservation of spermatozoa seems an absolute prerequisite in such situation for male patients who are old enough to procreate. We propose a national retrospective study carried out in 17 CECOS. This survey demonstrates a regular increase for semen preservation in testis cancer and analyses the modalities of gametes preservation and their possible use. In view of this activity, we propose a discussion of the attitude of the various CECOS and of particular cases involving ethical issues.

Adolescent↗