Micronuclei (MN) and other nuclear anomalies such as nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) are biomarkers of genotoxic events and chromosomal instability. These genome damage events can be measured simultaneously in the cytokinesis-block micronucleus cytome (CBMNcyt) assay. The molecular mechanisms leading to these events have been investigated over the past two decades using mo...

Although the risk factors contributing to the etiology of brain tumors remain largely unknown, this pilot study suggests that genetically determined sensitivity to environmental carcinogens may play a role in the pathogenesis of these tumors. In this study, we examined short-term lymphocyte cultures from 45 adult malignant glioma patients and 117 age-, sex-, and ethnicity-matched healthy contro...

Cleistanthin B, one of the toxic constituents of Cleistanthus collinus, was found to be cytotoxic to normal and tumour cells. In comparison with normal cells, tumour cells were sensitive to lower doses of toxin. The 50% growth inhibition (GI50) values for normal cell lines were from 2 x 10(-5) to 4.7 x 10(-4) M and for tumour cells the values ranged from 1.6 x 10(-6) to 4 x 10(-5) M. Short expo...

Bloom's syndrome (BS), a disorder associated with genomic instability and cancer predisposition, results from defects in the Bloom's helicase (BLM) protein. In BS cells, chromosomal abnormalities such as sister chromatid exchanges occur at highly elevated rates. Using Xenopus egg extracts, we have studied Xenopus BLM (Xblm) during both unperturbed and disrupted DNA replication cycles. Xblm bind...

Cells with non-functional poly(ADP-ribose) polymerase (PARP-1) show increased levels of sister chromatid exchange, suggesting a hyper recombination phenotype in these cells. To further investigate the involvement of PARP-1 in homologous recombination (HR) we investigated how PARP-1 affects nuclear HR sites (Rad51 foci) and HR repair of an endonuclease-induced DNA double-strand break (DSB). Seve...

The formation of chromosome aberrations induced by alkylating agents such as mitomycin C has been shown to require the passage of the treated cell through S phase. However, the exact mechanisms by which mitomycin C-induced DNA lesions are translated into chromosome aberra tions during S phase are not known. The purpose of these studies was to better understand the molecular basis of chromosome ...

chromosomal appearance of 12 holstein bulls selected for artificial inseminations were examined bysister chromatid exchanges (sces). for differential staining of sister chromatids bromodeoxyuridine (brdu)was inoculated in lymphocyte cultures. the mean, maximum and minimum number of sce per cell weredetermined 6.8 ± 1.14, 8.3 ± 1.1 and 5.7 ± 1.5, respectively. sce frequencies of all animals were...