ture yielded 15 additional cases of dicentric Y chromosomes. Among the cases, a wide range ofvariation in phenotype, external genitalia, histology, and chromosomal findings was observed. Factors possibly contributing to such variability are discussed and include: the exact site of breakage and exchange in the Y chromosome; the timing of dicentric formation (meiotic vs mitotic); the occurrence o...

Here we report an 8 years old girl who had post natal growth deficiency, microcephaly, facial dysmorphism, partial syndactyly of the second and third toes, susceptibility to infections, leukocytosis, immunodeficiency, adenopathy, but now sign of telangiectasia, ataxia and in evolution developed malignancy. Chromosomal analysis showed anomalies. By combining clinical manifestations and laborator...

A case of T lymphoblastic leukemia (T-ALL) showing t(1;7)(p34;q34) as the sole karyotypic abnormality was investigated at the molecular level. Screening of a phage library of tumor DNA with a probe for the beta T cell receptor gene (TCRB), which maps to chromosomal band 7q34, resulted in the isolation of a clone containing DNA spanning the translocation breakpoint of the der(1) chromosome. This...

13 children with ataxia-telangiectasia were followed for 6 years. Unlike previously reported cases, these patients had progressive, debilitating neurological disease and slight pulmonary or infectious symptoms. Immunological dysfunction was variable and endocrinological defects were absent. Oculomotor findings, alpha-fetoprotein levels, and the incidence of chromosomal breakage were the most co...

The patients evaluated in this study were classified into three groups of severe, moderate, and mild according to the severity of exposure to sulfur mustard. We evaluated the Immunological and Cytogenetical status of the patients after eight years of their exposure to sulfur mustard. The investigations revealed that the number of neutrophils, lymphocytes and monocytes in the patients with sever...

Genetic instability is a hallmark of cancer. Most tumors show complex patterns of translocations, amplifications, and deletions, which have occupied scientists for decades. A specific problem arises in carcinomas with a genetic defect termed chromosomal instability; these solid tumors undergo gains and losses of entire chromosomes, as well as segmental defects caused by chromosome breaks. To da...

Bleomycin exposure evoked a specific sensitivity in five ataxia telangiectasia (AT) long-term lymphoblastoid cell lines when compared to lines derived from four normal individuals or three patients with xeroderma pigmentosum. At all concentrations tested or after each treatment regimen, statistically significant differences in viability and cytogenetic damage were obvious, with the AT cell line...

Interactions between ends from different DNA double-strand breaks (DSBs) can produce tumorigenic chromosome translocations. Two theories for the juxta-position of DSBs in translocations, the static "contact-first" and the dynamic "breakage-first" theory, differ fundamentally in their requirement for DSB mobility. To determine whether or not DSB-containing chromosome domains are mobile and can i...

Rearrangements in the Mixed Lineage Leukemia breakpoint cluster region ( MLL bcr) are frequently involved therapy-induced leukemia, a severe side effect of anti-cancer therapies. Previous work unraveled Endonuclease G as critical nuclease causing initial breakage bcr response to different types chemotherapeutic treatment. To identify peptides protecting against we screened hemofiltrate-derived ...

Bleomycin exposure evoked a specific sensitivity in five ataxia telangiectasia (AT) long-term lymphoblastoid cell lines when compared to lines derived from four normal individuals or three patients with xeroderma pigmentosum. At all concen trations tested or after each treatment regimen, statistically significant differences in viability and cytogenetic damage were obvious, with the AT cell lin...