Chromosome Damage In Lymphocytes Research Articles

Micronuclei in Cytokinesis-blocked Lymphocytes of Cancer Patients Following Fractionated Partial-body Radiotherapy

We applied the cytokinesis-block micronucleus assay to measure chromosome damage in lymphocytes of 11 cancer patients undergoing fractionated partial-body irradiation. Measurements performed before, during and after cessation of radiotherapy showed a dose-related increase in micronucleus frequency in each of the patients studied. When the results for micronucleus frequency (Y) were plotted against the estimated equivalent whole-body dose (X) the dose-response relationship obtained was Y = 75.8X + 49.5 (r = 0.783, P less than 0.0001). A general decline in MN frequency was observed during the post-treatment period down to 57 per cent (+/- 10) after 12 months but there was considerable variation between individuals. The advantages and disadvantages of the application of the cytokinesis-block micronucleus assay as a biological dosimeter for lymphocytes irradiated in vivo are discussed.

Increased bleomycin-induced chromosome damage in lymphocytes of patients with common variable immunodeficiency indicates an involvement of chromosomal instability in their cancer predisposition.

To study mutagen-induced chromosome instability in cancer disposition, late S and G2 lymphocytes of 15 patients with common variable immunodeficiency and 14 healthy controls were exposed to bleomycin in vitro. The groups did not differ in the frequency of spontaneous chromosome aberrations. In bleomycin-treated samples we found higher numbers of break events per cell and increased frequency of cells with aberrations compared to the control group. A slightly reduced breakage of chromosome group D was noted in patients. These results support the hypothesis that a higher incidence of cancer in patients with genetically determined immunodeficiencies may be explained by an increased mutagen-induced chromosome instability in at least some of them.

Bleomycin-induced chromosome breakage in G2 lymphocytes of retinoblastoma patients.

Retinoblastoma (Rb) cells may be more sensitive to X-irradiation than normal cells when assayed for clonogenic survival, suggesting that such sensitivity can be used as a trait for detecting RB1 gene carriers. We studied induction of chromosome damage in lymphocytes from patients with Rb by the radiomimetic antineoplastic antibiotic, bleomycin (BL). Lymphocytes were treated in G2 for 4 h at four concentrations of the drug (0.0, 0.3, 0.9, and 2.7 micrograms/ml), and chromosome damage was evaluated. No difference in levels of spontaneous or induced damage was detected among hereditary Rb, non-hereditary Rb, and normal lymphocytes. The role of X-ray treatment in the induction of second tumors in Rb patients is discussed.

Sister chromatid exchange and chromosome aberration rates in a group of psoriatics before and after a course of PUVA treatment.

Blood was cultured and chromosome preparations were examined for sister chromatid exchanges and chromosome aberrations in eighteen patients receiving photochemotherapy with 8-MOP and UV-A for the treatment of psoriasis, both before starting treatment and again 6 months later. The UV-A was administered both by means of low output (irradiance: 1.1--2.25 mW/cm2) and high output (irradiance: 6.1--7.6 mW/cm2) UV-A radiation cubicles. Irrespective of the intensity of irradiation or the total dose of UV-A administered there was no evidence of chromosome damage in lymphocytes following treatment.

Heroin and chromosome damage.

The article by Matsuyama et al, Chromosomes in Patients Receiving Methadone and Methadyl Acetate, in theArchives(35:989-991, 1978) is of interest to us because our laboratory has studied the frequency of chromosome damage in lymphocytes cultured from patients who have abused heroin.1-3In our studies, informed consent was obtained from all persons. In most instances, 50 cells from each person were analyzed for breaks, dicentrics, fragments, rings, or exchange figures. A summary of the longitudinal studies shows that in comparison with the cells of normal controls (Table), the cells of heroin addicts who have not been treated show an increased amount of chromosome damage after 72 hours in culture (0.4% as compared with 2.7%, which is statistically significant (ϰ21= 13.8,P≤.0001). This high level of damage persists in persons who remain in the methadone program for up to three months, but it then