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Biomedical subjects

W Feichtinger

Publications and source records attributed to W Feichtinger.

At least 109 records · Page 6Linked to original sources
PubMed1988

On the highest chromosome number in mammals.

The mitotic and meiotic chromosomes of the semiaquatic rodent Ichthyomys pittieri (Rodentia, Cricetinae) from Venezuela were analyzed by means of conventional staining and several banding techniques. The diploid chromosome number of this rare species is 2n = 92, which is the highest value known for mammals. It is assumed that this exceptionally high chromosome number is the result of repeated centric fissions. The karyotype of I. pittieri was compared with that of Anotomys leander, for which a diploid number of 2n = 92 has also been reported. The karyological relationships existing within the Neotropical Cricetidae are summarized.

Animals↗
PubMed1987

The fragile site (17)(p12): induction by AT-specific DNA-ligands and population cytogenetics.

The rare fragile site at 17p12 can be induced in lymphocyte cultures with the AT-specific DNA-ligands distamycin A, DAPI, Hoescht 33258 and berenil. The optimum culture conditions for the experimental induction of fra(17)(p12) were studied. There are indications that fra(17)(p12) is a late-replicating chromosome region in which AT-rich DNA is located. The fragile site also occurs spontaneously in cell cultures of most fra(17)(p12) carriers. A population screening of 250 unselected individuals showed that the frequency of carriers heterozygous for fra(17)(p12) is 2%. The results are compatible with a population being in Hardy-Weinberg equilibrium with respect to fra(17)(p12) and its non-fragile allelomorph. Neither the heterozygous nor the homozygous condition of fra(17)(p12) have any deleterious effects.

Adult↗
PubMed1987

The fragile site (16)(q22). II. Sister chromatid exchanges.

In the lymphocytes of heterozygous carriers of the rare autosomal fragile site (16)(q22) an exceptionally high frequency of sister chromatid exchanges was demonstrated at the induced fragile site by means of simultaneous berenil and BrdU treatment of the cultures. The rate of sister chromatid exchanges at q22 is also increased in the fragile chromosome 16 by treating the cells with BrdU alone. The possible reasons for the preferential occurrence of induced and spontaneous sister chromatid exchanges at fra (16)(q22) are discussed.

Bromodeoxyuridine↗
PubMed1987

Morphological anomalies in the placentae of IVF pregnancies: preliminary report of a multicentric study.

Macroscopic characteristics of 100 fetal adnexae from pregnancies obtained by in-vitro fertilization and embryo transfer (IVF-ET) were compared with data for normal pregnancies taken from the literature. Material was obtained from 63 singleton, 15 twin, one triplet and one quadruplet pregnancies. The fetal and placental weights as well as the fetal:placental weight ratio were within the normal range for gestational age. Whilst placental morphology was normal, the insertion of the umbilical cord was frequently abnormal. Marginal (15%) and velamentous (14%) insertions of the umbilical cord were found more frequently than in a general obstetrical population (6% and 1% respectively). Excluding placentae from multiple pregnancies (which are known to have a higher incidence of abnormal cord insertion) the frequency did not decrease and remained significantly higher than in a normal population (P less than 0.01 and P less than 0.001, for marginal and velamentous insertion respectively). Abnormal insertion of the cord is of major clinical importance because of its association with vasa praevia and fetal haemorrhage (Benkiser Syndrome). Since this condition is thought to be caused by disturbed orientation of the blastocyst at implantation it is probably related to the IVF-ET procedure.

Embryo Implantation↗
PubMed1986

The fragile site (16) (q22). I. Induction by AT-specific DNA-ligands and population frequency.

The rare fragile site at 16q22 was experimentally induced in lymphocyte cultures with various AT-specific, non-intercalating DNA-ligands. The optimum conditions for the induction of fra(16)(q22) were determined. The best expression of fra(16)(q22) was found with the aromatic diamidine berenil which is recommended for further studies on this fragile site. The results indicate that fra(16)(q22) is a region with AT-rich, late replicating DNA. The simultaneous treatment of lymphocytes with berenil and aphidicolin (inhibitor of DNA polymerase alpha) induces both the rare fra(16)(q22) and the common fra(16)(q23) within the same chromosome. A population study on 350 unselected individuals showed that fra(16)(q22) is the most common of all rare autosomal fragile sites in man. The frequency of individuals heterozygous for fra(16)(q22) is 5.1%, no homozygosity for fra(16)(q22) was detected. Statistical analysis indicates that the population is in Hardy-Weinberg equilibrium with respect to the fragile and non-fragile chromosomes 16.

Base Sequence↗
PubMed1986

The use of synthetic culture medium and patient serum for human in vitro fertilization and embryo replacement.

The use of heat-inactivated patient serum as both fertilization and embryo replacement medium was compared in a prospective randomized study with a fully synthetic culture medium containing human serum albumin without serum addition (B3 INRA Menezo). Another series of the author's IVF program was analyzed retrospectively when a commercially available synthetic medium with bovine serum albumin (B2 INRA Menezo) or B3, as mentioned above, was used without serum addition for fertilization but with 50-100% patient serum as embryo replacement medium. Fertilization rates were significantly higher in the synthetic culture media (70%) than in serum (57%). The rate of polyploid fertilization was significantly lowest in B3 medium. There was a clear trend toward better pregnancy rates when high-percentage or 100% patient serum was used for embryo replacement, no matter if one, two, three, four or more embryos were replaced. We conclude that there should be no need for any kind of serum addition to fertilization media. The present study proves our previous observation that the use of serum seems to be beneficial as embryo replacement medium. This might well be explained by a "protein stick effect" due to the high macromolecular contents of serum rather than by viscosity measurements, since no significant increase in viscosity was observed when a high percentage of serum was added to culture media.

Blood↗
PubMed1986

Transvaginal sector scan sonography for needle guided transvaginal follicle aspiration and other applications in gynecologic routine and research.

A transvaginal sector scanner probe has been developed for precise needle-guided transvaginal follicle aspiration under sonographic control. The first results of transvaginal needle-guided follicle aspiration are presented. A high recovery rate was obtained (86% /follicle). The pregnancy rate after in vitro fertilization and embryo replacement was remarkably high (21.3%/cycle). Because exceptionally high-quality images of the organs in the pelvis are obtained, there are numerous other potential applications for the trans-vaginal sector scanner.

Female↗
PubMed1986

Trans-vaginal oocyte retrieval using a trans-vaginal sector scan probe combined with an automated puncture device.

A new trans-vaginal sector scanning ultrasound probe has been developed providing a forward viewing sector of 240 degrees. Due to its rotating one-beam scanner, the images of the uterus and the ovaries with their follicles are of high resolution and are clearly outlined on the screen. An automated puncturing device has been adjusted to this probe which gives the surgeon more precision in placing the tip of an aspiration needle into the middle of the follicle. This combination of a trans-vaginal ultrasound probe with an automated puncturing device for aspirating oocytes for in-vitro fertilization avoids the need for a full urinary bladder, with less discomfort for the patients and permits easy orientation because the organs of the pelvis are within a close range. More accurate follicular punctures can thus be performed. First experiences with 40 oocyte retrievals revealed that 79% of oocytes were recovered and the incidence of clinical pregnancy was 17.5%.

Female↗
PubMed1986

Smoking and in-vitro fertilization.

One-hundred and fourteen patients who underwent IVF treatment were asked about their smoking habits. Their rhodanide (SCN) concentrations were then estimated in serum and follicular fluid. SCN has been identified as an indicator for the amount of cigarettes smoked. The IVF outcome of non-smokers was compared with that of the smokers and no significant differences of fertilization rate and pregnancy rate between the two groups were found, but the SCN concentrations in serum and follicular fluid were increased in smokers (P less than 0.05). The effect of cigarette smoke toxins was perhaps not observable because other factors influencing the IVF treatment could possibly overlap with the influence of these particular toxins.

Adult↗
PubMed1986

Prednisolone supplementation to Clomid and/or gonadotrophin stimulation for in-vitro fertilization--a prospective randomized trial.

In a prospective randomized trial, 73 patients received prednisolone, 7.5 mg daily, for one cycle in addition to Clomid and/or gonadotrophins, while another 73 patients were not given the corticosteroid. In-vitro fertilization (IVF) resulted in 16 versus six clinical pregnancies in the prednisolone and the non-prednisolone group, respectively (P less than 0.05). Oestrogen was significantly higher under prednisolone during the ovulatory phase, while LH was significantly lower. The adrenal androgen dehydroepiandrosterone sulphate was markedly depressed by prednisolone and testosterone was also markedly lower in the prednisolone group. A stress-related androgen excess might occur in some patients undergoing IVF with consequent cystic degeneration of some follicles as in polycystic ovarian disease. Prednisolone might counteract this detrimental effect by depressing adrenal and ovarian androgens.

Clomiphene↗
PubMed1986

[Initial results of a cryopreservation program for human ova and embryos].

A human egg and embryo freezing program for non fertilized eggs and spare embryos was established recently in our ib vitro fertilization clinic. The first results are reported. Two cryoprotectants, glycerol and dimethylsulfoxid (DMSO) were used in an automatic computerized freezing program. DMSO gave us better results in terms of a 55% survival of all blastomeres (from 6 normal and 5 pathologic 2- to 16-cell embryos) after thawing. Some of the thawed embryos continued cleavage in vitro. Four embryo replacements were performed with the 6 normal embryos, but none of them resulted in pregnancy. The rapid technique using glycerol gave us less good results in terms of blastomere survival (34%); however, from 3 embryo replacements one "biochemical pregnancy" was obtained from a thawed four-cell embryo. At first attempts to freeze and thaw unfertilized eggs, DMSO seemed also to give better results. The presented cryopreservation techniques which are modifications of those published by Trounson et al. and Zeilmaker et al. need further improvement although the first results are encouraging.

Computers↗