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U Wolf

Publications and source records attributed to U Wolf.

At least 55 records · Page 3Linked to original sources
PubMed1988

An in vitro model of gonad differentiation in the chick embryo. Roller cultures in gas permeable biofoil bags.

Embryonic gonads of 6 1/2 to 12 days old chick embryos were enzymatically dissociated. The cell suspensions were cultured in small gas permeable bags of foil (Biofolie Heraeus) in a roller culture apparatus. The cells formed multiple small aggregates, in which sex specific differences developed within two days. In cell suspensions of embryonic testes smooth spheric aggregates formed with well delineated testicular cords in the center and a tunica albuginea-like mesenchymal layer at the outside. Most of the male germ cells were incorporated in the central cords. A number of germ cells were barred from entering the cords by the tunica albuginea-like mesenchymal layer and populated the outer surface of the aggregates. The aggregates of left ovary were irregular in shape and characterized by clusters of germ cells residing in an outer cortical zone. The aggregates of the right ovary, which regresses in vivo, showed poor growth and did not differentiate, thus, indicating that the suppression of right ovary was not removed in culture. In the roller cultures of dissociated embryonic gonads male and female morphogenesis was mimicked in a reproducible manner, so that the system can be used for further experimental studies of gonadal development.

Animals↗
PubMed1988

Serological H-Y antigen in the female chicken occurs during gonadal differentiation.

In the chicken, serological H-Y antigen is specific for the female sex. Male gonad differentiation can be experimentally influenced by estrogens, resulting in the transient formation of an ovotestis. The sex-inverted gonad becomes positive for H-Y antigen. Therefore, the question arises whether, in normal gonadogenesis also, the female gonad at the indifferent stage, before estrogens are produced, is negative for H-Y antigen. Here we show that this is indeed the case. The female gonad becomes positive for H-Y antigen when the ovary starts its organotypic differentiation at about day 6 1/2 of embryonal development. It is assumed that estrogens are responsible for the occurrence of H-Y antigen. This finding supports the view that H-Y antigen plays a role in primary ovogenesis in the chicken.

Animals↗
PubMed1988

An in vitro model of gonad differentiation in the chicken. Estradiol-induced sex-inversion results in the occurrence of serological H-Y antigen.

Dissociated cells from the gonads and mesonephros of 8-day-old chicken embryos were reorganized in rotation culture. The aggregates obtained from gonadal cells exhibited specific morphologic and histologic sex differences. In the presence of estradiol, aggregates from testicular cells showed characteristics similar to control ovarian aggregates, while in ovarian aggregates under estradiol treatment the female organization became more pronounced. Determination of serological H-Y antigen revealed that male aggregates of gonads and mesonephros were negative for H-Y and those of female embryos were positive for H-Y. Administration of estradiol did not change the H-Y findings in female aggregates. In contrast, in the male, gonadal cultures became H-Y positive while mesonephros cultures remained negative. It is assumed that estradiol induces the occurrence of H-Y antigen in the gonads.

Animals↗
PubMed1987

Absence of Y-specific DNA sequences in human 46,XX true hermaphrodites and in 45,X mixed gonadal dysgenesis.

A search for Y-specific DNA sequences has been performed in a sample of seven 46,XX true hermaphrodites and one 45,X mixed gonadal dysgenesis case and compared with a sample of 11 XX males. Using six Y-specific DNA probes no hybridization signal was obtained in the hermaphrodite group; in contrast, all XX males gave a positive signal with at least one probe. This difference is statistically highly significant. We conclude that the aetiology of true hermaphroditism is different from that of the XX male syndrome. As all cases of the hermaphrodite group are positive for the serological sex-specific antigen (Sxs) it is concluded that this antigen can be present even in the absence of Y-specific DNA.

DNA↗
PubMed1987

The occurrence of serological H-Y antigen (Sxs antigen) in the diandric protogynous wrasse, Coris julis (L.) (Labridae, Teleostei).

The serological sex-specific (Sxs) antigen (previously called 'H-Y antigen') has been shown, in various vertebrate species ranging from fish to mammals, to be characteristic of the heterogametic sex. We studied a protogynous hermaphrodite, Coris julis, in order to examine whether the change of a female to a secondary male also involves a change in the Sxs-antigen phenotype. The (homogametic) females of this species were found to be Sxs negative, while both primary and secondary males were Sxs positive. This was true not only for gonads but also for nongonadal tissues. The administration of androgen to females is known to cause sex inversion in this species; we were able to demonstrate this again at the histological level, and found that androgen results in a Sxs positive phenotype in all tissues studied (gonads, spleen, muscle). We propose that androgen is responsible, directly or indirectly, for the occurrence of the Sxs antigen.

Animals↗
PubMed1986

[Programmed electric stimulation following acute myocardial infarct. Significance of stimulation timing].

To assess the influence of time on the inducibility by programmed electrical stimulation of ventricular arrhythmias after acute myocardial infarction, we studied 18 patients on the 5th and 24th day after infarction with a stimulation protocol employing a maximum of 3 right ventricular extrastimuli during sinus rhythm and at 3 paced cycle lengths. All patients were without documented sustained ventricular arrhythmias (sustained ventricular tachycardia or ventricular fibrillation) prior to the investigation. Sustained ventricular arrhythmias were induced in 2 patients on day 5, but in 9 on day 24 after infarction. This difference in incidence was statistically significant (p less than 0.05), as was the change in the distribution ratio of induced sustained ventricular arrhythmias from day 5 to day 24 (p less than 0.05). The types of arrhythmia induced on day 24 were sustained ventricular tachycardia with a mean cycle length of 207 ms in 6 cases (5 monomorphic, 1 polymorphic), and ventricular fibrillation in 3 cases. These 9 patients did not differ from the remaining 9 patients in maximal CPK, infarct site, number of stenosed coronary arteries, global left ventricular ejection fraction, and in the results of 24-hour Holter monitoring, but they had a significantly shorter right ventricular effective refractory period (223 +/- 10 ms versus 259 +/- 28 ms; p less than 0.05). During the follow-up period of 24 +/- 5 months no patient died, had syncopal attacks, or developed spontaneous episodes of sustained ventricular arrhythmia. The timing of programmed electrical stimulation with a maximum of 3 right ventricular extrastimuli strongly influences the inducibility of sustained ventricular arrhythmias after acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Determination of 5-aminolevulinic acid in biological samples by high-performance liquid chromatography.

5-Aminolevulinic acid (ALA), the common precursor of all naturally occurring tetrapyrroles, forms a stable condensation product with 2-amino-3-hydroxynaphthalene which can be identified by its fluorescence. Separation of the compound by reversed-phase high-performance liquid chromatography on RPC-18 columns allows its detection down to the picomolar range and can be successfully applied for ALA analysis in small biological samples. The reaction product of ALA with 2-amino-3-hydroxynaphthalene has been synthesized and characterized.

Aminolevulinic Acid↗
PubMed1985

A 45,X male with evidence of a translocation of Y euchromatin onto chromosome 15.

A 19-year-old male with azoospermia was found to have a 45,X karyotype with additional euchromatic material on 15p. The parents' karyotypes are normal. The cytogenetic data, the positive H-Y-typing, and the presence of Yp-specific restriction fragments detected in the proband's genome by molecular DNA probes suggest that the short arm of the Y chromosome, including part of the centromere, is translocated onto the nucleolus organizer region (NOR) of chromosome 15.

Adult↗
PubMed1983

The X linked recessive form of XY gonadal dysgenesis with a high incidence of gonadal germ cell tumours: clinical and genetic studies.

Five phenotypic females in one family had the genotype 46,XY and all had gonadal germ cell tumours. Studies of the family pedigree suggest that this form of XY gonadal dysgenesis is inherited in an X linked recessive manner. G banding of elongated metaphase chromosomes from two subjects with XY gonadal dysgenesis and a female carrier showed no aberrations of the X chromosome. The titres of H-Y antigen in three girls with XY gonadal dysgenesis were in the male control range. Thus it appears that, in the X linked form, XY gonadal dysgenesis may be caused by a point deletion or mutation of a gene on the X chromosome, which controls the gonad specific receptor for the H-Y antigen. Studies of Xg blood groups were uninformative about linkage of Xg with the X borne gene causing the XY gonadal dysgenesis. Dermatoglyphic studies in the girls with XY gonadal dysgenesis and female carriers revealed high a-b palmar ridge counts and a tendency for the A mainline to terminate in the thenar area. Both of these features have been described in patients with Turner's syndrome.

Adolescent↗
PubMed1983

H-Y antigen in human X-autosome translocations.

The distal segment of the X chromosome short arm (Xp223) escapes X-inactivation in the normal female. This was shown by the activity of three genes assigned to this segment, those for Xg, STS, and H-YB. In contrast, in cases with non-random X-inactivation due to structural aberration of one X chromosome, the genes for Xg and STS may undergo inactivation. In this article, it is shown that in X-autosome translocation, the H-YB gene which modifies the activity of H-Y antigen, may be inactivated as well. Evidence is presented that in these cases, expression of all three genes on Xp223 is concordant.

Animals↗
PubMed1983

[Use of electronic data processing for quality control in perinatal medicine].

Pregnancy, delivery and neonatal period are influenced by many factors, which effect on perinatal and neonatal mortality and morbidity on the other-hand. Numerous parameters are to be recorded and analyzed for control of quality. With conventional technic of data processing this is only possible in large perinatological centers on a restricted scale. Therefore the electronic data processing project "perinatal medicine" was developed for recording important perinatological efficiency parameters. It was introduced in the practice of gynecological and infant hospital in Karl-Marx-Stadt.

Computers↗
PubMed1982

[Genetics of sexual differentiation].

Sexual differentiation normally proceeds in a series of consecutive steps including sex determination, gonadal differentiation, genital development, and the realization of somatic and psycho-social sex characteristics. Deviations from the normal course are known at each level of this process, resulting in sex reversal and intersexuality. Many of these abnormalities can be traced to genetic mutations. From the level of the differentiated gonad onwards, further sexual development is largely controlled by endocrine functions which are fairly well understood. By contrast, the development of the as yet undifferentiated gonad into either testis or ovary is hormone-independent, and is now believed to be due to the presence or absence of a cell surface component, the H-Y antigen. While the exact mechanism of H-Y antigen action is still under study, its biological function in testicular differentiation is well established. There are a number of mutations which interfere with normal primary gonadal differentiation, and it can be concluded from these mutations that several different genes are involved in this basic step of sexual development. Of these genes comprising the H-Y antigen system, some have regulatory, others structural functions. The H-Y antigen system promises to become a model for the understanding of the genetic control of cellular differentiation.

Disorders of Sex Development↗
PubMed1982

Correlation between the number of sex chromosomes and the H-Y antigen titer.

H-Y antigen was studied serologically on blood cells and cultured fibroblasts of patients with numerical aberrations of the sex chromosomes. As compared with normal males, patients with the karyotypes 48,XXXY and 49,XXXXY have reduced H-Y antigen titers; a tendency toward reduced titers can also be detected in the 47,XXY Klinefelter syndrome. The existence of an intermediary titer was further substantiated by a quantitative absorption test applied to cells with the 49,XXXXY karyotype. It appears that in the presence of one Y chromosome, the H-Y antigen titer decreases with an increasing number of X chromosomes. In contrast, the H-Y antigen titer is increased if, at a given number of X chromosomes, the number of Y chromosomes is increased, as in the 47,XYY male. Consequently, patients with 48,XXYY chromosomes are in the male control range. The findings are interpreted under the hypothesis of a controlling or modifying influence of the sex chromosomes on the titer of H-Y antigen.

Adolescent↗