Genotoxicity of Gamma Radiation Against Lymphocytes of Radiation Workers: The Cytokinesis-Block Micronucleus Assay

<b>Background and Objective:</b> Gamma irradiation induces genotoxicity, characterized by the formation of extra-nuclear bodies and left behind during the anaphase stage of cell division, often referred to as a micronucleus (MN). The present work aims to monitor exposure to ionizing radiation as a genotoxic agent in the lymphocytes of workers at radiation energy centers. <b>Materials and Methods:</b> The lymphocyte cytokinesis block micronucleus assay used and analyzed the correlation between the Nuclear Division Index (NDI), age, blood type and the number of micronuclei (MN). Blood samples were collected from 20 volunteers in heparin tubes, exposed to 2 Gy gamma rays and cultured <i>in vitro</i>. <b>Results:</b> A significant difference in the number of micronuclei between blood group A and blood groups A, B and AB. The Nuclear Division Index (NDI) value for lymphocytes of radiation energy center workers after gamma radiation was significant (1.74±0.1) but still within the normal range. Neither MN frequency nor NDI values correlated with age, but MN frequency showed a correlation with blood type. <b>Conclusion:</b> The gamma irradiation did not induce a cytostatic effect but proved genotoxic to the lymphocytes of radiation energy center workers. Notably, blood type A demonstrated higher sensitivity to gamma radiation.

Micronucleus frequency in Danish schoolchildren and their mothers from the DEMOCOPHES population

Micronucleus (MN) frequency is a biomarker for early genetic effects which is often used in human biomonitoring studies. Increased frequency of micronuclei has been associated with high levels of traffic exposure. Further high MN frequency was found predictive for cancer development in several studies of adults. In the present study, the MN frequency in blood samples from the Danish participants of the European pilot project DEMOCOPHES was analysed and related to the area of residence, self-reported and calculated exposure to road traffic as well as to mercury in hair and blood concentrations of persistent organic pollutants and dioxin-like activity measured in the same participants. The MN frequency analysis was performed with the cytokinesis-block micronucleus (CBMN) assay and included 100 children and 119 mothers. We found a significant correlation between mothers and children in the levels of micronuclei in 1000 binucleated T lymphocytes (‰MNBN) and in the proliferation index. Further the levels of ‰MNBN were significantly higher in mothers compared with their children. No significant associations were found for ‰MNBN for traffic related exposure in neither children nor their mothers. In children, a 2.5 times higher micronuclei in mononuclear T lymphocytes were found in children living within 50 m of a busy road, however, this was not found in mothers or in MNBN and the effect of exposure to road traffic on MN frequency needs further investigation. No significant associations were found between MN frequencies and the other biomarkers measured in the same participants.

Investigation of genotoxicity in acromegaly from peripheral blood lymphocyte cultures using a micronucleus assay

CONTEXT

Although patients with acromegaly may have an increased risk of developing several types of cancers, the degree of risk for malignancy in these patients is unresolved.

OBJECTIVE

The present study aimed to investigate the potential genotoxic effects of acromegaly on the cell cycle in peripheral blood lymphocyte cultures.

DESIGN

This was a single center, crossover, case-control study conducted on the acromegalic patients in Turkey.

SETTING

The study was conducted in the outpatient clinic of a university hospital.

PATIENTS

Seventy-one consecutively screened acromegalic patients and 56 controls participated in the study.

INTERVENTION

Patients were included, regardless of the disease activity status and their treatment duration before the study.

MAIN OUTCOME MEASURES

The primary end point was the frequency of micronucleus (MN) in the peripheral blood lymphocyte cultures, and the secondary end point was its clinical correlations.

RESULTS

The MN level was 3.82 ± 1.49 in the control group and 18.00 ± 6.13 in the acromegalic group (P < .01), whereas the nuclear division index (NDI) was 1.79 ± 0.12 in the control group and 1.68 ± 0.07 in the acromegalic group (P < .01). Neither MN nor NDI was correlated with age, GH, IGF-I, initial GH, initial IGF-I, duration of the remission period, and initial tumor size. Only the MN level was positively correlated with the duration of disease (r = 0.323, P = .014).

CONCLUSION

Our results indicated that acromegalic patients had genotoxic damage at a substantial level, and there was a positive correlation between the duration of disease and genotoxicity level.