Biomedical subjects

B Imthurn

Publications and source records attributed to B Imthurn.

5 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

A transdermal regimen for continuous combined hormone replacement therapy in the menopause.

Transdermal systems for oestrogen therapy in the menopause have become very popular. The compliance, however, is impeded by the cyclic addition of oral progestins which leads to monthly withdrawal bleeds. In this pilot study a skin patch releasing 0.05 mg oestradiol and 0.25 mg norethisterone acetate per day, which was originally designed for sequential therapy, was used in a continuous manner. Results were quite favourable. Menopausal complaints were efficiently relieved and the Kupperman score dropped from 27.6 to 5.0. Out of 10 women, 1 had mild breakthrough bleeding, and 7 patients recorded one or several spotting episodes, mainly within the first 3 treatment months. No endometrial hyperplasia was observed and there was no significant change in plasma lipids, i.e. cholesterol, triglycerides, HDL-, HDL2-, HDL3-cholesterol, LDL-cholesterol and apolipoproteins A1 and B. The regimen might be a useful alternative to oral continuous combined replacement therapy.

Administration, Cutaneous↗

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↗