Dissociation as probable origin of mosaic 45,XY,t(15;21)/46,XY,i(21q).
(9/193)
A patient is described with some features of Down's syndrome and a 45,XY, t(15;21)(15qter leads to 15p13::21p11 leads to 21qter)/46,XY,i(21)(qter leads to cen leads to qter) karyotype. Two mechanisms are proposed for the origin of the mosaicism, one assuming the dissociation of a translocation (15;21) chromosome already present in the zygote, and the other involving a chromatid translocation in a 46,XY zygote. The possible independent origin of the two cell lines is also considered. (+info)
Two balanced translocations in three generations of a pedigree: t(7;10) (q11;q22) and t(14;21) (14qter to cen to 21qter)1.
(10/193)
A reciprocal chromosome translocation between 7q and 10q and an unrelated Robertsonian translocation involving 14q and 21q were found in a healthy 44-year-old man, in his normal 18-year-old son, and in his mother. They were ascertained through the man's brother, whose grandson has Down's syndrome as a result of an inherited 14q21q translocation. To our knowledge, this is the second report of a karyotype with both reciprocal and Robertsonian translocations in a single subject, and only the fourth report of independently segregating double translocations occurring in more than one generation. (+info)
Transformation of human cells by SV40 virus.
(11/193)
Fibroblast cultures were prepared from skin biopsies from 29 patients and tested for their susceptibility to transformation by simian virus SV40. Cells with a normal chromosome complement showed a mean transformation frequency of 25/106 cells but for cells from a single patient with Fanconi's anaemia, the value was 152/106 cells. An increased susceptibility to transformation was observed for cells from 6 patients with Down's syndrome 3 patients with trisomy 18, a patient with trisomy 18 for 5% of cells and a patient with trisomy 13. No increased susceptibility to transformation was found for cells with a chromosome complement of XO, XXY, XX/XX + 8, XX + partial 15q or XX + 9p. The susceptiability to transformation was related to susceptibility to SV40 virus infection, as measured by the number of infected cells which contained SV40 virus induced T antigen. This latter test was technically easier to perform and could serve to detect persons of increased susceptiability to transformation, since this may indicate an increased risk of natural malignant disease. (+info)
Cigarette smoking, familial hematopoietic cancer, hair dye use, and risk of t(14;18)-defined subtypes of non-Hodgkin's lymphoma.
(12/193)
Some evidence suggests that smoking, a family history of hematopoietic cancer, and use of hair dyes are associated with t(14;18)-defined subsets of non-Hodgkin's lymphoma (NHL) in men. To further evaluate these associations and to expand them to women, the authors determined t(14;18)(q32;q21) status by fluorescence in situ hybridization in 172 of 175 tumor blocks from a population-based case-control study conducted in Nebraska during 1983-1986. Exposures in 65 t(14;18)-positive cases and 107 t(14;18)-negative cases were compared with those among 1,432 controls. Odds ratios and 95% confidence intervals were calculated using polytomous logistic regression. Among men, smoking was not associated with risk of t(14;18)-positive or -negative NHL. Among women who had ever smoked cigarettes, there was an association with risk of t(14;18)-negative NHL (odds ratio (OR) = 1.9, 95% confidence interval (CI): 1.1, 3.3) but not t(14;18)-positive NHL (p-difference = 0.01). The risks for t(14;18)-negative NHL among women increased with longer duration (>30 years: OR = 2.1, 95% CI: 1.1, 4.1) and early initiation (age +info)
Fetal nasal bone in screening for trisomies 21, 18 and 13 and Turner syndrome at 11-13 weeks of gestation.
(13/193)
Epstein-Barr virus and human chromosomes: close association of the resident viral genome and the expression of the virus-determined nuclear antigen (EBNA) with the presence of chromosome 14 in human-mouse hybrid cells.
(14/193)
Fourteen hybrid clones derived from the fused cultures of human lymphoblastoid FV5 cells and 5-bromodeoxyuridine-resistant mouse fibroblastic MCB2 cells grown in hypoxanthine/aminopterin/thymidine selective medium were examined for the presence of Epstein-Barr virus (EBV) DNA, the expression of the virus-determined nuclear antigen (EBNA), and the presence of human chromosomes, in the course of serial passage in vitro. Among the hybrid clones tested, 3 were positive for EBV DNA and EBNA, whereas the remaining 11 were totally negative. The chromosome investigations showed that human chromosome 14 was consistently involved in all three EBV genome-positive and EBNA-positive hybrid clones, but not in any negative clones. In 10 subclones isolated from 1 of the 3 positive clones, all of which contained only chromosome 14 of the human chromosomes, a concordant segregation of EBNA, EBA DNA, and chromosome 14 was evident. These findings suggest that the resident EBV genome is closely associated with chromosome 14 and the presence of this particular chromosome alone is sufficient for the maintenance and the expression of EBV genetic information in human lymphoblastoid cells. (+info)
Preferential somatic pairing between homologous heterochromatic regions of human chromosomes.
(15/193)
The cytidine analog 5-azacytidine (5-azaC) induces an undercondensation of the heterochromatin in human chromosomes 1, 9, 15, 16, and Y when it is added in low concentrations to the late S-phase of growing lymphocyte cultures. In interphase nuclei, these heterochromatic regions are frequently somatically paired. The somatic pairing configurations are preserved up to metaphase stage in the 5-azaC-treated cultures and are thus susceptible to a direct microscopical examination. The statistical analysis of 1,000 somatic pairing configurations from 5-azaC-treated cells showed that the somatic pairing between the heterochromatic regions of homologous chromosomes is preferred over that between nonhomologous chromosomes. (+info)
A chromosomal breakage syndrome with profound immunodeficiency.
(16/193)
The chromosomal breakage syndromes--ataxia-telangiectasia, Fanconi's anemia, and Bloom's syndrome--are associated with growth failure, neurologic abnormalities, immunodeficiency, and an increased incidence of malignancy. The relationship between these features is unknown. We recently evaluated a 21-year-old female with more severe chromosomal breakage, immunodeficiency, and growth failure than in any of the mentioned disorders. As of November 1985, the patient remains clinically free of malignancy. At age 18, the patient's weight was 22.6 kg (50th percentile for seven years), height was 129 cm (50th percentile for eight years), and head circumference was 42 cm (50th percentile for six months). Laboratory studies demonstrated a marked decrease in both B and T cell number and function. The peripheral blood contained 400 to 900 lymphocytes/microL with 32% T11 cells, 17% T4 cells, and 21% T8 cells. The proliferative responses to phytohemagglutinin (PHA), pokeweed mitogen, and concanavalin A were less than 10% of control. There were 1% surface IgM positive cells, and serum IgG was 185 mg/dL, IgM 7 mg/dL, IgA 5 mg/dL. In lymphocyte cultures stimulated with the T cell mitogens PHA, phorbol ester, and interleukin 2, 55% of the banded metaphases demonstrated breaks or rearrangements. The majority of the breaks involved four fragile sites on chromosomes 7 and 14, 7p13, 7q35, 14q11, and 14q32. These are the sites of the genes for the T cell-antigen receptor and the immunoglobulin heavy chain and are sites of gene rearrangement in lymphocyte differentiation. Epstein-Barr virus stimulated B cells and fibroblast cultures also demonstrated a high incidence of breaks, but the sites were less selective. These findings suggest that the sites of chromosomal fragility in the chromosomal breakage syndromes may be informative and that factors other than the severity of the immunodeficiency or the high incidence of chromosomal damage may contribute to the occurrence of malignancy in the chromosomal breakage syndromes. (+info)