PubMed Health⌕ Search

Biomedical subjects

K D Zang

Publications and source records attributed to K D Zang.

At least 91 records · Page 5Linked to original sources
PubMed1987

Loss of heterozygosity and the origin of meningioma.

In some human tumors, loss of particular genes manifested indirectly by loss of heterozygosity for specific RFLPs seems to uncover either heterozygous deletions leading to a gene doses effect or homozygous deletions due to a silent allele at the corresponding locus, both causing the loss of regulatory functions (antioncogenes, suppressor genes). Meningioma, a benign human tumor derived from the coverings of brain and spinal cord, is associated with complete loss, rarely deletion, of one chromosome 22. About 60% of meningiomas exhibit monosomy 22 in all or part of cells; however, about 40% display a normal karyotype. Comparison of constitutional and tumor genomes from 12 patients showed loss of heterozygosity on 22 in three cases, suggesting the involvement of events at the DNA level.

Adult↗
PubMed1987

Enhanced expression of four cellular oncogenes in a human glioblastoma cell line.

Examination of a human glioblastoma cell line displaying a relatively stable karyotype and absence of both copies of chromosome #13 (HeRo) as well as of a SV-40 transformed subline (HeRo-SV) using analysis on the DNA and RNA level showed that both cell lines express high levels of abl, erb B, myc, and Ha-ras mRNA. Neither gene amplification nor gene rearrangement at the loci concerned nor abnormal transcription account for this activation of expression. The possible influence of the deleted sequences in the context of a suppressor gene hypothesis is discussed.

Cell Line↗
PubMed1986

Polysomy of chromosome 7 is correlated with overexpression of the erbB oncogene in human glioblastoma cell lines.

Chromosome analysis in a series of human glioblastoma cell lines (HeRo, HeRo-SV1, A172, T406, T508, T705) has indicated characteristic changes in the karyotype, the most striking and consistent of which is a significant increase in the copy number of chromosome 7, with up to 8 copies per metaphase. As determined by Spurr et al., chromosome 7 represents the genomic locus for the oncogene erbB (7pter-q22). Therefore, we have compared the number of chromosomes 7 to the levels of expression of the erbB oncogene. Interestingly, in all of them erbB-specific mRNA was found to be increased at levels even higher than expected from the number of chromosomes 7 found. In contrast, in an astrocytoma of slightly lower grade of malignancy (cell line T567), neither polysomy 7 nor significant expression of the erbB oncogene was noted.

Astrocytoma↗
PubMed1985

Establishment and characterization of a human glioblastoma cell line with a stable karyotype and nullisomy 13.

A permanent cell line (HeRo) with a stable karyotype (80-84,XXYY) and with defined numerical and structural chromosome aberrations was established from a human glioblastoma, a highly malignant brain tumor. Transformation of these cells with SV40 led to a second permanent cell line (HeRo-SV) with a reduced, but also stable, karyotype (72-74,XXYY). The morphological appearance of the glioblastoma line was similar to the main component of the original tumor tissue. The transformed cells differed from their counterparts in accelerated growth, enhanced growth in soft agar, reduced growth conditions, expression of SV40 T antigen, and altered epitheloid morphology. Both cell lines have been grown in continuous culture for more than 2 years. The stability of both the biologic properties and the karyotypic changes induced by SV40 is quite remarkable. Both lines show a nullisomy 13.

Brain Neoplasms↗
PubMed1983

Influence of hyperthermia on the phosphorylation of ribosomal protein S6 from human skin fibroblasts and meningioma cells.

Skin fibroblasts and meningioma cells, derived from primary cultures of the same patients have been used to study the influence of hyperthermia on (i) cell morphology and (ii) phosphorylation pattern of ribosomal and ribosome-associated proteins. Incubation of tumour cells and fibroblasts up to 7 h at 42 degrees C did not significantly change the cell morphology as compared to control cells kept at 37 degrees C. At 42 degrees C ribosomal protein S6 is shifted cathodically indicating a loss of negative charge, however no quantitative dephosphorylation of S6 was observed. Meningioma cells and fibroblasts did not differ significantly with respect to S6 phosphorylation.

Cells, Cultured↗
PubMed1982

Quantitative studies on the arrangement of human metaphase chromosomes. IX. Arrangement of chromosomes with and without spindle apparatus.

The spatial relationships in human male metaphase cells treated with and without colcemide were compared with each other. The following results were obtained: (1) In normal male metaphases the overall distributions of chromosomal distances regardless of chromosome identification numbers did not show normal distribution, neither in the colcemid-free sample nor in the colcemide-treated sample. (2) In both samples larger chromosomes showed a more peripheral position, and smaller chromosomes showed a more central position. This finding was statistically significant. (3) No differences between the two samples could be observed concerning the following parameters: overall distributions of the centromere-centromere distances, distributions of the distances between the homologous chromosomes (except the small acrocentric chromosomes), rank positions of the mean distances between homologous chromosomes, and rank positions of the mean distances of the different chromosomes from the center of the mitosis (except few chromosomes). (4) Visible, but not statistically accessible, differences appeared between the two samples in respect to rank positions of the mean distances of all possible acrocentric pairing groups, rank positions of the mean distances of the homologous acrocentric chromosomes from the center of the mitosis, and distances of the X chromosome from the center of the mitosis. (5) Statistically significant differences appeared between the two samples with respect to distance distributions of the small acrocentric chromosomes and positions of the chromosomes 1, 16, 18, Y, and 21, 22 in relation to the center of the mitosis.

Chromosome Mapping↗
PubMed1982

Cytogenetic studies on the nucleolar organizer region [NOR] activity in meningioma cells with normal and hypodiploid karyotypes.

The association pattern and NOR silver staining of the acrocentric chromosomes was studied in normal and hypodiploid cell lines of four meningioma patients. In three cases the hypodiploid cells showed a more increased association frequency or NOR silver staining or both than the normal ones, indicating a compensatory mechanism between the NORs. Chromosomes #14 seemed to be more frequently involved in this phenomenon than other acrocentric chromosomes. From the silver staining results it was concluded that in meningioma cells, chromosomes #22 which bear active as well as inactive NORs were missing. The compensation between the NORs was probably only activated if an active NOR was lost.

Cell Line↗
PubMed1982

Interstitial de novo deletion of the long arm of chromosome 5: mapping of 5q bands associated with particular malformations.

A new case of interstitial deletion of the long arm of one chromosome No. 5 (q13 leads to q22) is described. The girl shows mental retardation, severe hypotonia, dysmorphic facies and peculiar dermatoglyphics. The relationship between partial trisomies and partial monosomies of 5q chromosomal segments and associated clinical features is discussed. It seems possible to draw a rough phenotypic map of the long arm of chromosome 5 (5q), correlating observed malformations and phenotypic features with specific chromosomal regions.

Abnormalities, Multiple↗
PubMed1981

Dermatoglyphic peculiarities in Down's syndrome detection of mosaicism and balanced translocation carriers.

The combination of dermatoglyphic patterns and the number and intensity of traits characteristic for Down's syndrome can be statistically expressed by the "Walker" index and the "general" index. More than 96% of a Down's syndrome series and a control series could clearly be separated by the general index. Cytogenetic and dermatoglyphic features were studied in 17 patients with mosaic trisomy 21 and their parents. In the 17 cytogenetically diagnosed patients with mosaic Down's syndrome, a highly significant correlation was observed between the percentage of trisomic cells and the presence of traits characteristic for this syndrome in the dermatoglyphic patterns. The diagnostic problems and the value of dermatoglyphic examination in cases of mosaicism, where the trisomic cell line seems to have disappeared, is discussed. The results of our study also indicate an elevated incidence of a specific dermatoglyphic pattern combination with general index values similar to Down's syndrome in one parent in nearly 20% of Down's syndrome children. The possibility of hidden mosaicism in these parents of Down's syndrome children is discussed. Furthermore, the dermatoglyphic patterns in a large kindred with an inherited 15/21 translocation (21/41 carriers of the balanced translocation; 14/41 chromosomally normal; 6/41 mongoloid members) was analyzed. The data obtained from this translocation family and especially the values obtained in the general index indicate that some dermatoglyphic stigmata are directly associated with the D/21 translocation carrier state and can therefore be used for predicting this state.

Chromosomes, Human, 13-15↗
PubMed1980

Association frequency and silver staining of nucleolus organizing regions in hyperthyroid patients.

The intensity of the silver staining of nucleolus organizing regions (NORs) and the frequency of chromosomal associations were studied before and after antithyroid treatment in seven and eight hyperthyroid patients, respectively. For one patient, the NOR staining was significantly more intense after treatment, while for another the opposite result was found. A higher stainability of chromosome 22 was observed after treatment in six of seven patients. The difference was significant for the group of patients considered as a whole but only for one patient considered separately. Chromosome 22 also showed an increased association frequency. Fro one patient, the number of large associations and the total number of associating chromosomes was also significantly increased after treatment. A decrease of associating chromosomes 14 and 21 such as was reported by Nilsson et al, (1975) after antithyroid treatment could not be found in our sample. The possible reason for this difference are discussed.

Chromosomes, Human↗
PubMed1980

Dermatoglyphs in carriers of a balanced 15;21 translocation.

Cytogenetic and dermatoglyphic features were studied in a large family with an inherited 15;21 translocation. Of 35 healthy members of the family, 21 carried the translocation chromosome and 14 were chromosomally normal. There were six members with Down's syndrome who had the translocation. Dermatoglyphic studies showed that carriers of this balanced translocation had the following peculiarities significantly more often than the general population. On the hands, they had ulnar loops on the fingertips, symmetrical high terminations of the A line, symmetrical ulnar loops on the hypothenar areas, distal loops in the 3rd interdigital areas, open fields in the 4th interdigital areas, axial triradii in the distal position, and single transverse palmar creases (Sydney lines). On the feet, they had small distal loops on the hallucal area and distal loops in the 4th interdigital areas. The translocation carriers also had significantly more often than non-carrier relatives symmetrical high terminations of the A line, open fields in the 4th interdigital areas, distal axial triradii, and Sydney lines. On the feet, they had small distal loops on the hallucal areas, distal loops in the 4th interdigital areas, and tibial loops on the proximal hypothenar areas. The data obtained from this study, and especially the values of the Walker and general indices, indicate that some of the dermatoglyphic stigmata of Down's syndrome are directly associated with the 15;21 translocation carrier state and can therefore be used for predicting that state.

Chromosomes, Human, 13-15↗
PubMed1979

Quantitative studies on the arrangement of human metaphase chromosomes. VII. The association pattern of acrocentric chromosomes in carriers of Robertsonian translocations and in their relatives with normal karyotypes.

The pattern of association of acrocentric chromosomes was examined in ten and five carriers of a 15/21 and a 13/14 Robertsonian translocation, respectively, and was compared with that of the same numbers of relatives with normal karyotypes. In the carriers of 15/21 translocation, the number of large associations (involving more than two acrocentrics) and the association frequencies for individual acrocentric chromosomes, were significantly higher than in the control group. The mean number of associations of the single homologs of the translocation chromosomes was much higher than that of the other acrocentrics. In the carriers of 13/14 translocations, only the association frequency for chromosome 13 was higher than in the normal relatives. The uninvolved chromosomes homologous to those involved in translocation showed an insignificant increase in associations in comparison with the other acrocentrics. These results suggest that some mechanism within the cells compensates for the effect of missing acrocentrics or of acrocentrics lacking NORs on the number of associations. The possible relations of this phenomenon to the activity of the nucleolus organizing regions are discussed.

Chromosome Banding↗