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Biomedical subjects

P Hirsch

Publications and source records attributed to P Hirsch.

At least 19 recordsLinked to original sources
PubMed1992

Prenatal diagnosis by amniocentesis in 82 pregnancies after in vitro fertilization.

We report on the outcome of 82 amniocenteses (AC) carried out during pregnancies after in vitro fertilization (IVF) from 1-1-1985 to 31-12-1989. The main indication for amniocentesis was a maternal age of greater than or equal to 35 years. In 48 cases, we found an anterior placenta and assumed that this was related to the position in which the uterine embryo transfer was performed. In six pregnancies, we found an abnormal karyotype, including two cases of trisomy 21; the two couples decided for abortion. Four aberrations in the fetal karyotypes were also present in either the mother or the father, the resulting children are healthy. The further course of pregnancies after IVF and AC was characterized by a higher incidence of toxemia, uterine bleeding before the 28th week of gestation, abruptio placentae, and premature deliveries, when compared to the course of pregnancies after spontaneous conception. We believe that these occurrences were not caused by AC, as the incidence was higher in all our pregnancies after IVF (without AC) and has also been reported in pregnancies after ovarian hyperstimulation without IVF. Therefore, we see no reason to renounce AC after IVF. However, the special risks inherent in pregnancies after IVF must always be discussed with the couple.

Adult↗
PubMed1992

Mutagenesis and chromosome mobilization in Hyphomicrobium facilis B-522.

Spontaneously derived antibiotic-resistant mutants of Hyphomicrobium facilis B-522, a restricted facultative methylotroph, occurred at a high frequency on agar plates with low antibiotic concentrations. Mutants specifically defective in methanol oxidation have been obtained using an allyl alcohol direct selection technique. By chemical mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine in the presence of chloramphenicol several stable auxotrophic mutants could be isolated: three leucine auxotrophs, two threonine auxotrophs, and two leucine-methionine double auxotrophic mutants. Optimal conditions for transposon mutagenesis have been developed by comparing several transposon delivery vectors. With the suicide plasmid pRK2013 as a vector, the tetracycline resistance conferring transposon Tn5-132 was introduced into the genome of H. facilis B-522. The following insertion mutants have been obtained: leu-3::Tn5-132, ilv-1::Tn5-132, and pur-1::Tn5-132. Broad host range IncP-1 plasmids could be successfully transferred by interspecific matings. Chromosome mobilization was demonstrated with the conjugative IncP-1 plasmids RP1, R68.45, pMO60, and H. facilis 2189 (leu-2, met-1, mox-1, nfs-1, str-12) as recipient strain. Transconjugants occurred at frequencies ranging from 10(-6) to 10(-8) for each marker.

Bacteria↗
PubMed1992

Cervical cancer.

Explore the source record for details and available documents.

Carcinoma in Situ↗
PubMed1991

Follicle stimulating hormone stimulates the production of gonadotrophin surge attenuating factor (GnSAF) in vivo.

OBJECTIVE: To study the time-course production of gonadotrophin surge attenuating factor (GnSAF) after the onset of FSH treatment in women. DESIGN: Normally cycling women were treated with FSH injections (225 IU per day) starting on cycle day 2 (0800 h). The response of LH to an i.v. injection of 10 micrograms GnRH (GnSAF bioactivity) was investigated 12, 24, 36 and 48 hours after the first FSH injection, as well as during the early follicular phase of an untreated spontaneous cycle. PATIENTS: Six normally ovulating women with long-standing unexplained infertility were studied. The women were used as their own controls during the spontaneous cycles. MEASUREMENTS: Pituitary response to GnRH was calculated as the net increase in LH at 30 min (delta LH30) above the basal value. RESULTS: delta LH30 was significantly attenuated 12, 24, 36 and 48 hours after the first FSH injection as compared to the spontaneous cycles. In the latter cycles, delta LH30 decreased significantly from day 2 (12 hours) to day 4 (48 hours). Serum oestradiol levels at 12 and 24 hours did not differ significantly between the FSH and the spontaneous cycles. CONCLUSIONS: These results demonstrate that in superovulated women, a marked attenuation in the pituitary response to GnRH occurs as early as 12 hours from a single injection of FSH before any significant increase in serum oestradiol levels. It is suggested that FSH is a potent stimulus of GnSAF production in women.

Biological Factors↗
PubMed1991

Electron spectroscopic diffraction and imaging of the early and mature stages of calcium phosphate formation in the epiphyseal growth plate.

A review of different models of biomineralization in collagen-rich hard tissues shows that further investigations of crystal formation are necessary. The electron spectroscopic diffraction (ESD) mode of operation of an energy-filtering electron microscope offers the possibility of being able to avoid the background from inelastic scattering in selected-area electron diffraction patterns. First experiments on the different stages of mineralization in the epiphyseal growth plate have only indicated the presence of apatite. The ESD mode can be complemented by the electron spectroscopic imaging mode and by elemental mapping of calcium.

Animals↗
PubMed1990

Microbial colonization of aquifer sediment exposed in a groundwater well in northern Germany.

Microbial growth within the water-saturated subsurface environment was investigated by exposing sandy sediments to groundwater for 12 weeks at a depth of 10 or 20 m in a stainless-steel groundwater well. Washing and heating the sediment to 600 degrees C (removal of organic carbon) prior to the exposure did not prevent the natural microbial community from colonizing the sterilized sediment samples. Total cell counts of more than 10(7) or 10(8) per g of dried sediment were obtained. Viable cell counts of 10(5) cells per g on oligotrophic media indicated the presence, within the exposed sediment, of a highly active and multiplying biota. Microscopic analysis of enrichments inoculated with exposed sediment samples revealed a total of 45 different morphotypes, approximately 42% of the microbial community observed in previous studies of this site. The interstitial water running off of the retrieved sediment contained only 17 morphotypes and had up to 6 x 10(5) viable cells per ml.

Animals↗
PubMed1989

[Triple extra-uterine pregnancy following in vitro fertilization and embryo transfer].

The article reports on an ectopic pregnancy after IVF/ET that was characterized by the simultaneous nidation of three of the four transferred pre-implantation embryos in both (heavily damaged) Fallopian tubes. The ectopic nidation not only in one of the Fallopian tubes must be seen as a pointer to the importance of active mechanisms of transport from the cavum into the Fallopian tubes. Therefore it is unlikely that ectopic pregnancies after IVF/ET--even if the technique is satisfactory--can be avoided completely. In view of the fact that several IVF treatments were performed in vain, the nidation of three of the four transferred embryos must be interpreted as supporting the theory that the conditions in the Fallopian tubes are more favourable for the development of the human pre-implantation embryos.

Adult↗
PubMed1989

[Intra-tubal embryo transfer (IVF/IT-ET) in the treatment of non-tubal-induced sterility. Initial studies of the value of a new and expensive therapy procedure].

Intratubar embryo transfer is a form of sterility treatment, in which the in-vitro-fertilized pre-implantation embryos are transferred into the intact fallopian tube(s). This enables the benefits of in-vitro fertilization (information of the gamete fertilization behavior, specific incubation of dysmature oocytes, reduction of the polyploidy rate, risk of multiple pregnancies) to be combined with those of gamete intrafallopian transfer (GIFT; tubar environment for the further development of the pre-implantation embryos). Intratubar embryo transfer is indicated in cases of sterility that are not due to the fallopian tubes; in addition to idiopathic sterility, particular emphasis is put on a certain form of immunological sterility (antibodies against sperm antigens), which seems to be a special indication for this method. Intratubar embryo transfer demands a two sided approach. It is advisable to collect the oocytes transvaginally, guided by ultrasound, since general anaesthesia maybe dispensed with - if so desired. The embryo transfer itself still requires a pelviscopy, which is only performed once fertilization of the oocyte has been confirmed; which is in contrast to GIFT, in which pelviscopy is an inherent part of each treatment cycle. In spite of this advantage, intratubar embryo transfer is a method, which is associated with a high expenditure. The aim of the study was, to evaluate the success rate when all the alternative, less costly options have been exhausted. Our first results are demonstrating, that intratubar embryo transfer is successful, even as a second line therapy. Therefore the method has a significance in the treatment of sterility, not caused by the tubes and the expenditure, with which it is associated, can be justified.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Initial experiences with amniocentesis for prenatal diagnosis in pregnancy following in-vitro fertilization].

We report on first experiences with amniocentesis in 63 pregnancies after IVF treatment over a period of 3 years. It is shown, that there is no increased risk through amniocentesis; it does not require special precautions. Above average number of aberrations could be found in amniotic cultures in cases where it could be identified additionally in one parent. It remains to be seen, whether the small number and sterility causes were coincidental or manifest themselves in future, especially, if the sterility concerned can be classified as idiopathic. The occurrence of trisomy 21 in accordance with the frequency is to be expected in the group of persons over 35 years of age and no increased risk through IVF treatment can be found.

Adolescent↗