Biomedical subjects

E Macas

Publications and source records attributed to E Macas.

6 recordsLinked to original sources

PubMed1992

[In-vitro fertilization--progress in a method of sterility treatment].

UNLABELLED: The first IVF-baby (in-vitro fertilization) was born in England in 1978 and was greeted enthusiastically. But, despite the enormous effort invested, pregnancy rates were disappointingly low. Although in recent years the clinical pregnancy rate has increased worldwide to 15-20% per retrieval, a vast number of people remained unaware of this improvement. To demonstrate and analyze the progress of IVF we evaluated all 196 IVF treatments effected from 1988-1991 at Zürich University Hospital. With an initial clinical pregnancy rate of only 6% per retrieval in 1988, the rate improved to 35% (p < 0.025) in 1991. The crucial factors relating to this improvement were the 1990 introduction of the programmed short-term protocol for ovarian stimulation and reevaluation of the previously used embryo freezing technique. CONCLUSION: After a difficult start, IVF has become, if accurately indicated, a method of sterility treatment with a realistic pregnancy and delivery prospect.

Antibodies↗

PubMed1992

[Programmed stimulation for in vitro fertilization].

A programmed stimulation protocol for in vitro fertilisation was evaluated in order to perform oocytes aspiration from Tuesday to Friday only. For this purpose, norethisterone acetate (Primolut-Nor) was given in a daily dose of 10 mg for 10-25 days, starting on the 2nd day of the preceding cycle and ending on a Monday. The stimulation was started on the following Friday by administering daily 0.1 mg D-Trp-6-LHRH s. c. (Decapeptyl). In group A (preliminary study) the treatment with HMG 150 IU/d (Pergonal) was initiated two days later. In group B the treatment with HMG was individualised with respect to the initial dose and the starting point. 10 ultrasonographic, needle-guided, transvaginal aspirations were performed from January to March 1990 in Group A, 29 aspirations from April to December 1990 in Group B. Indication for IVF in all patients was tubal infertility. All aspirations were possible from Tuesday to Friday. In Group A 5 of 15 cycles (33%) had to be cancelled. A total of 53 oocytes (5.3 +/- 2.3 per aspiration) were retrieved. Cleavage per oocyte took place in 62%. There was no pregnancy. In Group B, the cancellation rate could be reduced to 3% (1/30 cycles; p less than 0.025). 227 oocytes were recovered (7.8 +/- 3.1 per aspiration; p less than 0.05) and there was a higher cleavage rate (74%, n.s.). The clinical pregnancy rate (with allowance for progressive introduction of freezing) increased to 30% per stimulation cycle (9/30, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Developmental capacities of two-cell mouse embryos frozen by three methods.

The following three methods were evaluated in order to obtain a most efficient freezing protocol for the preservation of two-cell mouse embryos: (a) slow cooling and slow thawing in 1.5 M dimethyl sulfoxide, (b) slow cooling and fast thawing in 1.5 M propanediol (PROH), and (c) ultrarapid freezing and fast thawing in either 3.5 M DMSO or 3.0 M PROH. In the slow-cooling procedures (a and b) ice nucleation (seeding) was induced manually or automatically. With method a, only a slight difference, 51.8% for manual and 58.9% for automatic seeding, was observed in survival rates, while the development to blastocysts was significantly affected: 35.4% with manual and less than 10% with automatic induction (P less than 0.001). Method b gave high survival (86.2%) and developmental rates (69.0%) with manual seeding compared with automatic seeding (20.7 and 9.8%, respectively; P less than 0.001). Using protocol c, higher survival and developmental rates were obtained with DMSO (84.8 and 55.9%) than with PROH (39.8 and 19.4%, P less than 0.001). These results demonstrate that inducing nucleation manually is superior to the use of a highly sophisticated autoseeding system and that method b with manual seeding is most effective in preserving the developmental capacity of two-cell mouse embryos after freezing and thawing. There is evidence that this is also true of human embryo cryopreservation.

Animals↗

PubMed1990

Abnormal chromosomal arrangements in human oocytes.

Ninety-one human oocytes, lacking signs of fertilization 50 h after insemination in vitro, were investigated cytogenetically to assess the frequency and type of chromosomal abnormalities. Chromosome spreading permitted adequate karyotyping in 55 oocytes. Non-determined numerical aberrations occurred with the following frequencies: hypohaploidy, 10.9% (6/55), hyperhaploidy, 14.5% (8/55) and hyperdiploidy, 3.6% (2/55). Total aneuploidy occurred with a frequency of 29.1% and was observed in oocytes from 30 patients. No correlation was found between specific chromosomal aberrations and type of infertility, stimulation treatment or gonadotrophin levels. On the other hand, the frequency of aneuploidy was significantly higher (P less than 0.05) in patients greater than 35 years of age. Two chromosomal complements (3.6%) had structural rearrangements; one oocyte had both structural and numerical chromosomal abnormalities and the other had differently condensed regions on the long arms of three chromosomes from group C. The overall frequency of chromosomal aberrations was 32.7%. Only two samples contained an additional set of polar body chromosomes. Thirteen oocytes presented sperm chromosomes in an arrested stage of premature chromosome condensation of the G1 phase and four oocytes showed asynchronous condensation of pronuclear chromosomes. Finally, it was concluded that the high proportion of chromosomal aberrations observed in human oocytes may contribute significantly to abnormal embryonic development in vitro.

Adult↗

PubMed1988

Prostaglandin F2 alpha, progesterone and estradiol concentrations in human follicular fluid and their relation to success of in vitro fertilization.

Prostaglandin F2 alpha (PGF2 alpha), progesterone (P4) and estradiol-17 beta (E2) in follicular fluid were measured by radioimmunoassay in patients undergoing in vitro fertilization and embryo transfer. Follicular growth was induced using clomiphene citrate-hMG-hCG (15 patients) and FSH-hMG-hCG (4 patients). There was no significant difference in follicular fluid PGF2 alpha and P4 concentrations relative to oocyte maturity as assessed morphologically. The highest PGF2 alpha concentration was found in fluid from FSH-hMG-hCG cycles where fertilization occurred. The value is significantly higher (p less than 0.002) than in fluid from clomiphene-hMG-hCG cycles whether fertilization took place or not. There was no significant difference in P4 and E2 levels in relation to the type of ovarian induction or success in fertilization. Positive correlation between P4 and E2 in follicular fluid was found (r = 0.404). The positive correlation between total dose of hMG given to the patients and PGF2 alpha concentration in their preovulatory follicular fluid (r = 0.434) suggests that PGF2 alpha is secreted locally as the result of hMG and hCG stimulation. It is proposed that PGF2 alpha could be a biochemical marker for assessing the success of in vitro fertilization.

Adult↗

PubMed1988

Chromosomal preparations of human triploid zygotes and embryos fertilized in vitro.

Forty-eight zygotes with more than two pronuclei were identified after in vitro fertilization, representing 6.1% of all fertilized oocytes. The chromosome preparations from pronuclear stage to the cleaved human embryos were examined. Prophase was found in eight out of ten zygotes. The spreading of chromosomes allowed an adequate counting in only two cases. Six of the eight preparations displayed a late prophase. In this stage each haploid group of chromosomes can be analysed separately. Kariogamy usually occurred 4 to 5 h after the pronuclei had disappeared, and polyploid number of chromosomes were found in well-spread metaphases. The chromosomal preparations were made for eleven human embryos arising from zygotes with three pronuclei. Out of ten preparations, where the chromosomes could be counted, seven embryos (70%) contained hypodiploidic groups of chromosomes. In two of the cases, however, triploid metaphases were found, and in the last one a triploid/diploid mosaicism.

Embryo, Mammalian↗