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Biomedical subjects

W Feichtinger

Publications and source records attributed to W Feichtinger.

At least 19 recordsLinked to original sources
PubMed1992

Fragile site (16) (q22). III. Segregation analysis.

The rare autosomal fragile site, fra (16) (q22), is the most common of all rare autosomal fragile sites and has a heterozygote frequency of about 5%. Evidence for it was found following the segregation expected from a simple codominant trait with complete penetrance; this is in contrast to a variety of other rare autosomal fragile sites. Based on the analysis of 12 families in which fra (16) (q22) is segregating, we found that, whereas complete penetrance could be confirmed, the transmitting parent was significantly more likely to be of the female sex. On the other hand, there was no evidence for preferential transmission to offspring of either sex.

Chromosome Fragile Sites↗
PubMed1992

Chromosome banding in Amphibia. XVII. First demonstration of multiple sex chromosomes in amphibians: Eleutherodactylus maussi (Anura, leptodactylidae).

A cytogenetic study performed on a population of the South American leptodactylid frog Eleutherodactylus maussi revealed multiple sex chromosomes of the X1X1X2X2 female/X1X2Y male (= XXAA female/XXAY male) type. The diploid chromosome number is 2n = 36 in all females and 2n = 35 in most males. The multiple sex chromosomes originated by a centric fusion between the original Y chromosome and a large autosome. In male meiosis the X1X2Y (= XXAY) multiple sex chromosomes form a classical trivalent configuration. E. maussi is the first species discovered in the class Amphibia that is distinguished by a system of multiple sex chromosomes. Only one single male was found in the population with 2n = 36 chromosomes and lacking the Y-autosomal fusion. This karyotype (XYAA male) is interpreted as the ancestral condition, preceding the occurrence of the Y-autosome fusion.

Animals↗
PubMed1992

Early stages of sex chromosome differentiation in fish as analysed by simple repetitive DNA sequences.

Animal sex chromosome evolution has started on different occasions with a homologous pair of autosomes leading to morphologically differentiated gonosomes. In contrast to other vertebrate classes, among fishes cytologically demonstrable sex chromosomes are rare. In reptiles, certain motifs of simple tandemly repeated DNA sequences like (gata)n/(gaca)m are associated with the constitutive heterochromatin of sex chromosomes. In this study a panel of simple repetitive sequence probes was hybridized to restriction enzyme digested genomic DNA of poeciliid fishes. Apparent male heterogamety previously established by genetic experiments in Poecilia reticulata (guppy) was correlated with male-specific hybridization using the (GACA)4 probe. The (GATA)4 oligonucleotide identifies certain male guppies by a Y chromosomal polymorphism in the outbred population. In contrast none of the genetically defined heterogametic situations in Xiphophorus could be verified consistently using the collection of simple repetitive sequence probes. Only individuals from particular populations produced sex-specific patterns of hybridization with (GATA)4. Additional poeciliid species (P. sphenops, P. velifera) harbour different sex-specifically organized simple repeat motifs. The observed sex-specific hybridization patterns were substantiated by banding analyses of the karyotypes and by in situ hybridization using the (GACA)4 probe.

Animals↗
PubMed1992

Successful clinical application of laser for micromanipulation in an in vitro fertilization program.

This is a report of our preliminary experience with assisted hatching by laser with a case of an ongoing twin pregnancy. We used an erbium laser to create a 20 to 30-micrometer opening in the zona pellucida of human embryos to facilitate the embryonic hatching after the embryo transfer. Our report proves that it is possible to obtain a pregnancy using a simple and quick laser method instead of mechanical or chemical procedures within the scope of micromanipulation.

Adult↗
PubMed1992

[Transvaginal Doppler study of embryonic heart action in early pregnancy].

Embryonic cardiac activity was observed by means of transvaginal Doppler ultrasound in a period from the 28th through the 78th day after conception (p. c.). We were able to detect a correlation between the embryonic heart rate and the stage of pregnancy as well as a correlation to the crown-rump length. The maternal age did not seem to have any effect on the appearance of embryonic heart activity. The number of registered Doppler echoes did not yield information on embryonic heart development.

Adult↗
PubMed1992

The use of fibrin sealant for embryo transfer: development and clinical studies.

Many embryo transfers after in-vitro fertilization may fail because of expulsion of the embryos from the uterus. Approximately 5-8% of pregnancies resulting from embryo transfer are ectopic. The aim of our study was to find a technique to avoid ectopic pregnancies and to improve the pregnancy rate. We used a two-component fibrin sealant which also contains a fibrinolysis inhibitor (aprotinin) at various concentrations. After gaining experience with mouse embryos, the sealant was used in human embryo transfer with great success. The results of a pilot study encouraged us to perform a prospective randomized study on 546 patients (270 with fibrin sealant, 276 conventional embryo transfers). There were 47 (17.0%) orthotopic pregnancies and 6 (2.2%) ectopic pregnancies in the control group, whereas there were 51 (18.9%) intrauterine and no ectopic pregnancies in the treatment group. The difference in ectopic pregnancies was statistically significant (P less than 0.05). With regard to the aprotinin concentration, there was a trend towards better results with 100-150 kIU (28.5% clinical pregnancies) in comparison to 250-300 kIU (19.2%) or no aprotinin (20.4%) (not significant). Further improvements of the technique may raise the pregnancy rate when fibrin sealant is used. As shown in our prospective randomized study, ectopic pregnancies may be completely avoided.

Adult↗
PubMed1992

'Chemical curettage' using intrauterine methotrexate injection.

A 22-year-old woman with multiple urogenital anomalies presented for the second time with a blighted ovum situated in the rudimentary right horn of a uterus communicans bicornis. A dilatation and curettage was not possible owing to the inaccessibility of this horn. The first blighted ovum was aborted in 1989 (at age 21 years) following the use of intramuscular prostaglandin therapy. On this occasion, therapy was by the transvaginal, intrauterine (intra-amniotic) instillation of 100 mg methotrexate and a complete abortion of the products of conception occurred. Similar to the treatment of ectopic pregnancy, in certain cases, termination of intrauterine pregnancies using local methotrexate injection may be considered.

Abortion, Therapeutic↗
PubMed1992

An intriguing Y chromosome in Heteromys anomalus (Rodentia, Heteromyidae).

The mitotic chromosomes of the pocket mouse Heteromys anomalus (Rodentia, Heteromyidae) from Venezuela were analyzed by means of conventional staining and various banding techniques. The karyotype of this species is distinguished by a Y chromosome with exceptional banding properties. The very large heterochromatic Y long arm shows a remarkable bright quinacrine fluorescence, but only moderate or dull fluorescence when labeled with other AT base pair-specific fluorochromes. The implications of these findings are discussed.

Animals↗
PubMed1992

Current technology of oocyte retrieval.

Transvaginal follicle puncture under sonographic control has become the method of choice for ovum retrieval worldwide. Because it is the current technology of the 1990s, there are very few reports in the literature on other methods of oocyte retrieval. Furthermore, perhaps because of the simplicity of transvaginal follicle puncture under sonographic control, there are only a few reports on the technique itself in the current literature. This review classifies the papers on hand according to general studies of the subject, appropriate anesthesia, necessity of follicle flushing for oocyte retrieval, vaginal disinfection and the evaluation of the risk following transvaginal oocyte retrieval, and new techniques in connection with the harvesting of oocytes.

Anesthesia↗
PubMed1991

[Vaginal ultrasonographic observation of uterine contractions in embryo transfer and its relevance to treatment success].

441 patients were treated by in-vitro fertilisation and embryo transfer (ET) from January 1989 to May 1990. Transvaginal ultrasound allowed pre-transfer assessment of the uterine architecture and confirmation of successful transfer after the procedure. The length and direction of the cervical and uterine cavity were noted. The real-time image was observed for one minute to see, if uterine contractions occurred. These can be clearly seen as pulsatile movements, which can be distinguished from breathing motions. We also recognised the localisation and the movement of the transferred air bubble. A "double bubble sign" occurs as a result of the two air bubbles being seen in sagittal transvaginal ultrasound. The embryos are sandwiched between the two visible bubbles. As far as the subjective methods used permit a definitive statement, there is no connection between contractions, localisation and movement of the air bubble with the success or failure of the E.T.

Embryo Transfer↗
PubMed1991

Clinical experience with ultra-rapid freezing of embryos.

A modified ultra-rapid freezing technique was introduced in January 1989 in our clinical in-vitro fertilization freezing programme. Thus, we wish to report our 1 1/2 year experience with ultra-rapid freezing as a simple and inexpensive method of routine cryopreservation. Of 181 frozen-thawed embryos, 110 (61%) survived with 50-100% blastomeres intact, and were used in 91 embryo replacements. Nine clinical pregnancies were established including two sets of twins. There was one miscarriage and one ectopic pregnancy. So far, five patients have delivered six normal, healthy infants and two other pregnancies are normally ongoing, including another twin pregnancy. These results were similar to those obtained by the conventional slow freezing method using propanediol. There is no doubt that there is a marked advantage of ultra-rapid freezing when compared to previous methods in terms of cost and time. We therefore believe that more clinical attention should be given to ultra-rapid freezing and it should become increasingly the method of choice for human embryo freezing in IVF programmes.

Clinical Protocols↗
PubMed1991

Environmental factors and fertility.

This review deals with the decrease of male and female fertility during the last few decades which might to due to harmful environmental influences, stress and pollutants. Particular attention is drawn to the extent to which alcohol, coffee drinking, cigarette smoking and environmental pollutants may influence human fertility. Possible influences of increased radiation exposure after the nuclear accident of Chernobyl and possible hazards of electromagnetic fields are also discussed. Continuing research on the effects of environmental pollution on reproduction should be intensified and supported.

Environment↗
PubMed1991

[Side effects of oral contraceptives in the first treatment cycle].

In order to compare the secondary effects of oral contraceptive pills during the first cycle of application, 308 women between the age of 25 and 45 were interrogated by questionnaires about their subjective complaints. The patients received a contraceptive within an In-vitro-Fertilization-program (IVF-program) in preparation for a stimulation treatment to follow. The study consisted of two parts: at the beginning a pilot study was carried out in which retrospectively a pill containing 0.150 mg Desogestrel and 0.030 mg Ethinylestradiol and a contraceptive containing 0.075 mg Gestoden and 0.030 mg Ethinylestradiol were compared. In a following prospective randomized examination a product, new on the market, containing 0.250 mg Norgestimat and 0.035 mg Ethinylestradiol, was included. The most common secondary effects, occurring in 34% of our patients, were spottings and break through bleedings. Regarding the secondary effects--during the first cycle of application--no significant difference between the contraceptives could be established.

Adult↗
PubMed1991

[Ultrasound monitoring of follicle growth in IVF].

Vaginal sonography is a well-established method to monitor follicular growth and to detect the optimum time for induction of ovulation with hCG. In this study we found significantly less and smaller follicles in the left ovary compared to the right. However, during the procedure of oocyte retrieval we found an equal number of follicles and oocytes in both ovaries. We assume therefore that the used sonographic method is less valid for the left ovary compared to the right. The reason could be that on the left side the ovary is often hidden behind the sigma which makes visualization by ultrasound more difficult. Vaginal sonography should therefore be performed on a gynecological chair where it is easier to bring the probe closer to the left ovary. On the basis of follicular fluid volume measurements at the puncture the sizes of the follicles on day hCG were calculated and resulted in a range of 14.7-20.7 mm for the average of all follicles.

Chorionic Gonadotropin↗