E A R L Y in radiation genetic investigations it was reported that X-ray-induced sex-linked recessive lethals were not homogeneous in composition. Instead they included: ( 1 ) apparent intragenic changes without observable cytological abnormalities (point mutations) ; (2) deficiencies; and (3) changes associated with and, for the most part, inseparable from chromosome rearrangements (OLIVER 193...

Clustered DNA damage induced by ionizing radiation is refractory to repair and may trigger carcinogenic events for reasons that are not well understood. Here, we used an in situ method to directly monitor induction and repair of clustered DNA lesions in individual cells. We showed, consistent with biophysical modeling, that the kinetics of loss of clustered DNA lesions was substantially comprom...

Latar belakang: Benzena sudah digunakan sejak lama dalam industri dan penggunaannya cenderung meningkat sehingga memerlukan pengendalian. Walaupun benzena industri dikendalikan < 1 ppm, namun efeknya masih terlihat, antara lain berupa patahan kromosom limfosit. Penelitian ini bertujuan mengevaluasi patahan kromosom limfosit sebagai efek pajanan benzena kurang 1 ppm di lingkungan kerja, dan fakt...

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...

P UTRESCINE has been found to induce chromosome aberrations in cells undergoing meiosis in Oenothera [8] but not in cells undergoing mitosis in roots of Vicia faba [9]. In re-examining the action of putrescine and cadaverine in less toxic concentrations [cf. 91, we have tested the ability of these polyamines either to induce chromosome breakage or to upset the process of chromosome condensation...

The frequency of chromosome aberrations in the lymphocytes of three established heterozygotes for the Bloom's syndrome gene (ages 67, 57, 46) was compared to that in controls (ages 68, 67, 61, 46, 34). The main part of the study was done on coded slides. No difference was found between the heterozygotes and the control group, except for one control (aged 46) who had a significantly higher numbe...

AIM To describe multiple retinal abnormalities in a patient with Bloom syndrome, including early macular drusen, diabetic retinopathy, and the onset of leukaemic retinopathy. METHODS Clinical data were collected over 1 year of follow up, and ocular abnormalities in Bloom syndrome were reviewed from the literature. RESULTS A 39 year old man with a rare autosomal recessive "chromosome breakag...

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...

Chromosomal instability occurs early in the development of cancer and may represent an important step in promoting the multiple genetic changes required for the initiation and/or progression of the disease. Telomere erosion is one of the factors that contribute to chromosome instability through end-to-end chromosome fusions entering BFB (breakage-fusion-bridge) cycles. Uncapped chromosomes with...