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Biomedical subjects

K Sperling

Publications and source records attributed to K Sperling.

At least 91 records · Page 5Linked to original sources
PubMed1983

Complementation studies between Fanconi's anemia cells with different DNA repair characteristics.

Hybrids were performed between cell lines derived from four patients with Fanconi's anemia in which different biochemical lesions have been postulated. Complementation studies in these hybrids based on the rate of mitomycin C-induced chromosomal damage supported the concept of allelic mutations. It was therefore concluded that intergenic heterogeneity plays a much lower role in Fanconi's anemia than in Xeroderma pigmentosum or Ataxia teleangiectasia, two other disorders with defective DNA repair.

Anemia, Aplastic↗
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↗
PubMed1982

[Prenatal diagnosis of genetic disorders by linkage analysis (author's transl)].

Most of the well-known monogenic disorders to date cannot be diagnosed prenatally. In principle, this problem can be overcome indirectly if the gene in question is linked to a cytogenetic, biochemical, or molecular polymorphism. In this respect, the last-mentioned will gain increasing importance in prenatal diagnosis in the near future. The problems of such linkage studies in X-linked, autosomal dominant, and recessive disorders are discussed. Prenatal diagnosis, monogenic disorders, linkage group analysis, chromosomal polymorphisms, DNA-sequence polymorphisms.

Adult↗
PubMed1982

Mutagenicity testing on non-selectively cloned Chinese hamster ovary cells with the protein-mapping method.

Chemical mutagenesis was studied on Chinese hamster ovary cells by protein mapping. Cell cultures were treated with methylnitrosourea and the cells were cloned in non-selective media. The proteins of single clones were separated by 2-dimensional electrophoresis and analysed for qualitative (electrophoretic mobility) and quantitative (staining intensity; presence/absence) changes in the protein patterns. The investigation included 26 clones derived from treated cells and 26 control clones. The total number of gene loci tested was calculated from the number of protein spots analysed: it amounted to about 33 800. The protein patterns revealed 2 alterations defined as qualitative variant proteins. No alteration of this type was found in the control group. The frequency of quantitative variant proteins was increased by more than 100% compared with the control group. Our results and theoretical considerations suggest that the cellular concentration of single proteins offers a sensitive parameter for mutagenicity testing.

Animals↗
PubMed1982

Analysis of protein patterns in two-dimensional gels of cultured human cells with trisomy 21.

The occurrence of one chromosome of the cell in triplicate (trisomy, Ts) should increase the amount of all cell proteins coded by genes located on this chromosome. Many other proteins should be altered in their quantity by regulator genes, present in a threefold dosage, and by several indirect effects of the trisomy. We used two-dimensional electrophoresis to investigate the effect of the human Ts 21 on the proteins. Cells from different individuals with Ts 21 were cultured. Seven cell lines were derived from skin tissue and four from cells in amniotic fluid, and two cell clones were raised from fetal lung with Ts 21 mosaic. Stained two-dimensional protein patterns from these cell lines were compared with control patterns, and clearly visible differences in the staining intensity of corresponding polypeptide spots were evaluated. A few quantitatively variant polypeptides occurred in all trisomic cell lines investigated that were of a particular cell type, but no variants were consistently present in all of the 13 cell lines investigated. However the total number of variants (including variants not found in all individual cell lines) was considerably higher in trisomic cells than in normal cells.

Amniotic Fluid↗
PubMed1981

Arrangement of prematurely condensed chromosomes in cultured cells and lymphocytes of the Indian muntjac.

Premature chromosome condensation (PCC) was induced in order to study the arrangement of muntjac chromosomes in the interphase nuclei of proliferating and resting cells with respect to their polarity and the spatial relationship between them. The data were compared with the situation in in situ fixed and colcemid blocked metaphases. It appears that in rapidly dividing cells almost all G1- and G2 interphase chromosomes exhibit the Rabl type polarized orientation. This pattern still predominates in G0 lymphocytes which may have been arrested at this stage for some months or even years. - The location of the small chromosome Y2 was found to be "central" in normal metaphases but "peripheral" in colcemid blocked mitoses. The behavior in the premature condensed chromosome preparations was intermediate. Measurements of centromere distances between all possible pairs of chromosomes as well as on the relative position of chromosomes in circular spreads revealed no evidence for homologous somatic association during interphase and metaphase or any other suprachromosomal ordering principle. Interphase chromosome orientation seems to be solely the result of chromosome arrangement of the foregoing anaphase. Association between heterochromatic regions or the nucleolus organizers did not substantially influence this pattern. There is no support for speculations that in mammalian cells close proximity of homologous sites is instrumental in functional cooperation.

Animals↗
PubMed1981

Evolution of muntjac DNA.

The extent of nuclear single-copy DNA divergence between Muntiacus reevesi and Muntiacus muntjak vaginalis (Cervidae), a species pair showing extreme karyotype differences but striking morphological similarity, is 2%, as judged from the thermal stability of interspecific DNA-DNA hybrids. A comparison of the total nuclear DNA reassociation kinetics of the two species indicates a reduction of lowly repetitive sequences in M. m. vaginalis.

Animals↗
PubMed1980

Genetic heterogeneity of Fanconi's anemia demonstrated by somatic cell hybrids.

Cells of patients with Fanconi's anemia (FA) are characterized by their high mitomycin C sensitivity. This specific response was used to study the question of heterogeneity in cell hybrids. After fusion of somatic cells of different FA patients and a normal control, the resulting hybrids were cytogenetically analyzed with respect to their mitomycin C susceptibility. Complementation--indicating heterogeneity--should lead to normal amounts of mitomycin C-induced chromosomal damage. No complementation was found in hybrids between cells of a classical FA patient and one without skeletal malformations. However, clear evidence for heterogeneity was observed in hybrids between cells of the latter patient with early onset and another with late onset of the disease. This confirms the assumption of Schroeder and coworkers based on the high intrafamilial correlation for age at onset.

Adult↗
PubMed1980

Antagonistic effect of cocultivation on mitomycin C-induced aberration rate in cells of a patient with Fanconi's anemia and in Chinese hamster ovary cells.

The rate of spontaneous chromosomal aberrations in fibroblasts of a patient with Fanconi's anemia was slightly reduced after cocultivation with Chinese hamster ovary (CHO) cells. However, after mitomycin C treatment, a significant reduction of induced chromosomal damage was found in the FA cells while a significant increase was observed in the CHO cells. This antagonistic effect could be attributed to some diffusible agent(s). The results are discussed with respect to the underlying mechanism of the disease.

Adult↗
PubMed1980

Different sensitivity of diploid and trisomic cells from patients with Down syndrome mosaic after treatment with the trifunctional alkylating agent trenimon.

Normal and trisomic cells of patients with Down syndrome mosaic offer the unique possibility to study the effect of an additional chromosome no. 21 against an identical genetic background. Here we show that a significant increase in the frequency of Trenimon induced sister chromatid exchanges (SCEs) and chromosome aberrations can be found in trisomic lymphocytes and fibroblasts as compared to disomic cells. The relative increase was clearly higher for chromosomal breaks than for SCEs.

Alkylating Agents↗
PubMed1980

Activity of rRNA genes in cells of a patient with Down syndrome mosaic.

Disomic and trisomic cells of a patient with Down syndrome mosaic were used to study the effect of the additional chromosome 21 against an identical genetic background. The frequency of AG staining and the participation in satellite associations were determined for each pair of acrocentric chromosomes. The additional chromosome 21 of the trisomic cells and its homologues proved to be regularly Ag positive. Therefore the trisomic cells showed more AG positive chromosomes and more satellite associations per cell than the diploid cells. Thus, no compensation for the additional rRNA-gene dose could be found in the cells of the trisomic line.

Cells, Cultured↗