Biomedical subjects

L Koulischer

Publications and source records attributed to L Koulischer.

At least 91 records · Page 5Linked to original sources

PubMed1980

Down's syndrome in Wallonia (South Belgium), 1971-1978: cytogenetics and incidence.

During the 8 year-period 1971-1978 inclusive, 268 newborn with Down's syndrome (DS) were ascertained in Wallonia (South Belgium). The chromosomes of all patients were analyzed. A standard trisomy 21 was observed in 259 cases (96.6%) and translocations in seven (2.6%). One mosaic (0.4%) and one case with a 47,XX,+21,5 p-karyotype (0.4%) were also found. The overall incidence at birth for the 8 year-period was of 0.123%. However, the comparison of the 2 four-year periods 1971-1974 and 1975-1978 showed an increased incidence in mothers below 35 during the second period, reaching a statistical significant level in Charleroi, and industrial and densely populated area of the region (Fisher's exact test: P = 0.016 less than 0.025). Young women have now become the principal source of DS patients in Wallonia. This change from the previous pattern happened abruptly in 1975, and strongly suggests that one or more persisting factors relating to meiotic non-disjunction of chromosome 21 are operating in this region since 1974, and affecting DS births from 1975 onwards.

Adolescent↗

PubMed1980

[46,XX,r(18), + mar karyotype in the niece of a leukemic patient with trisomy 21 and cri du chat chromosome (author's transl)].

The present observation concerns a female patient with a 47,XX, r(18), + mar karyotype. The size of the ring varies from mitosis to mitosis; generally it is very small. The presence of a small marker ("minute") may explain some phenotypic differences not usually observed in the "r(18) syndrome". This patient is the niece of a trisomic 21, who showed complex chromosome anomalies during the course of an acute leukemia from which he died.

Child, Preschool↗

PubMed1979

Organ culture of mammalian testis. III. Inhibin secretion.

Mouse testes were cultured for 19--20 days at either 31 or 37 degrees C with a change of medium every 4 days. After treatment with charcoal and dextran T, the recovered testis media were incubated with rat anterior pituitary cells, and secretions of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were estimated by radioimmunoassay 3 days later. FSH release was significantly lowered when pituitary cells were grown with media of testes cultured 31 degrees C compared to cultures grown with fresh medium or with media of testes cultured at 37 degrees C for more than 4 days. LH secretion was normal in one experiment and reduced in the other with the media of testes cultured at 31 degrees C. Treatment of testicular media by heat or trypsin reduced the inhibiting activity. After 8 days at 37 degrees C, both germinal and Sertoli cells were damaged in the testis cultures, while at 31 degrees germinal cells alone were destroyed, Sertoli cells remained normal. These studies suggest that (1) a substance which responds to the definition of inhibition (protein--preferentially acting on FSH) is secreted in the medium of testis culture; (2) inhibin is produced by Sertoli cells; (3) inhibin is secreted only if the temperature is inferior to 37 degrees C.

Animals↗

PubMed1978

[Organ cultures of mammalian testes. I. Adult mouse testis].

Organ cultures of adult normal mice testes have shown that the tubular structure is best preserved at 31 degrees C. With the simple anhormonal conditions we have used, the germ cells actively involved in meiosis disappear in ten days, following a stereotyped pattern. During the same time, Sertoli cells become enlarged, with a marked cytoplasmic vacuolisation. After 2 weeks in vitro, the seminiferous tubules are completely filled up with Sertoli cells and no more spermatocytes are recognized.

Animals↗

PubMed1978

[Centromere staining in ten species of ruminants by C and R banding techniques].

The centromeric regions of acrocentric or telocentric chromosomes of 10 species of the order Artiodactyla, suborder Ruminantia, have shown to be equally deeply stained either with the C-banding or the R-banding technique. These unusual staining properties could be linked with the presence of a particular type of chromatin. The importance of centromeric fusions linked with speciation in the Bovoidea is recalled.

Animals↗

PubMed1978

[Cellular receptors of gonadotropic hormones. Immunocytochemical evidence in rat testicle].

We have performed topical applications of HCG and LH on fixed paraffin-embedded sections of adult rat testes. Thereafter, immuno-cytochemical demonstration of the peptides was carried on and demonstrated that HCG and LH specifically bound to the cell membrane of Leydig cells. This technique is highly reproductible provided that adequate fixation (with formalin containing fixatives) as been performed.

Animals↗

PubMed1978

[Fate of Leydig cells in testicular organ culture].

In organ culture experiments, the Leydig cells of mouse testes can still be recognized after 12 days at 31 degrees C. HCG binding sites are effectively demonstrated. Meanwhile, when HCG is added at the initiation of the cultures, it is selectively stored in the cytoplasm of the Leydig cells. These findings point to a fairly good survival of Leydig cells in our tissue culture system.

Animals↗

PubMed1975

[Studies of the mitotic and meiotic chromosomes in infertile males].

The analysis of meiotic chromosomes in sterile males is all the more interesting as it is liable to disclose anomalies whilst the mitotic chromosomes are normal. We have described a pathological meiotic sequence observed in ten patients, very probably linked to their sterility. It would not appear an exaggeration to state that a combined study of mitotic and meiotic chromosomes tends to indicate that at least 15% of all cases of male sterility have chromosomal origin.

Aneuploidy↗

PubMed1974