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C Stock

Publications and source records attributed to C Stock.

61 records · Page 4Linked to original sources
PubMedDate not supplied

[Cytogenetic aspects of pediatric germ cell tumors].

We have performed in situ hybridization (ISH) studies predominantly on paraffin sections and on isolated nuclei of 22 pediatric germ cell tumors (GCTs) from 18 patients including 4 recurrences from three patients. In addition, we performed conventional cytogenetic analyses in three tumor samples. Because reports on cytogenetic studies in pediatric GCTs are scarce we focused our studies on those chromosome abnormalities frequently observed in adult GCTs. These included numeric and structural abnormalities of chromosomes 1 and 12 (e.g. isochromosome 12p) and numeric deviations of chromosomes 8, 10, X and Y. The histological subsets of the tumors investigated included two dysgerminomas (DGE), one seminoma (SE), one combined seminoma, two embryonal carcinomas (EC), two recurrent ECs, six pure yolk sac tumors (YST), five combined teratomas, one immature teratoma (IT) and two recurrences of IT, and three differentiated teratomas (TD). Similar to the GCTs in adults, additional copies of chromosome 12 were the most frequently observed numeric abnormalities. The analysis of two paraffin-embedded tumors suggested that changes in the size of the pericentromeric hybridization signals of chromosome 12 may be attributed to the presence of i(12)(p10). This was confirmed following the karyotype analysis of one EC which unequivocally revealed the presence of two i(12)(p10). Interestingly, using these probes, no chromosomal abnormalities were found in the pure TD or in the TD cells of mixed tumors containing a YST component. In the YST portion, however, the 1p deletions and/or numeric chromosome changes were present. Surprisingly, deletions at the short arm of chromosome 1, del(1)(p36.3), were frequently observed in malignant pediatric GCTs and were the sole abnormality detected in one case.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

T-lymphocyte subpopulations in rheumatoid arthritis. II. Definition by monoclonal antibodies.

Samples of peripheral blood of 27 patients with seropositive rheumatoid arthritis (RA) and 27 healthy age- and sex-matched controls were coded and studied for lymphocyte subpopulations. Monoclonal antibodies and indirect immunofluorescence were used to analyse subpopulations of purified T cells: OKT3 reacts selectively with all peripheral human T cells, OKT4 defines the helper/inducer subpopulation and OKT8 the suppressor/cytotoxic T cells. RA patients had a significantly lower relative lymphocyte count (p less than 0.001). whereas the percentage of all T cells was similar in patients and controls, RA patients had a significantly higher proportion of helper/inducer cells (62 +/- 1.3 vs. 56 +/- 1.0, p less than 0.005) and significantly decreased suppressors/cytotoxic cells (25 +/- 1.5 vs. 32 +/- 1.0; p less than 0.001). This resulted in an increased "immunoregulatory ratio" of helper to suppressor cells in RA patients (2.68 +/- 0.17) compared to their normal controls (1.83 +/- 0.10; p less than 0.001). The proportions of T cells expressing HLA-D-like antigens (defined by a monoclonal antibody to human Ia) was not different in patients and controls. These findings confirm conclusions derived from our previous study of T cell subsets defined by the expression of Fe-receptors (Tm and Tg), that in the peripheral blood of patients with RA, helper mechanisms predominate over suppressor mechanisms. This derangement of the immunoregulatory balance may have an important role in the pathogenesis of seropositive RA.

Adult↗