Radiation signature on exposed cells: Relevance in dose estimation

Abstract

The radiation is considered as a double edged sword, as its beneficial and detrimental effects have been demonstrated. The potential benefits are being exploited to its maximum by adopting safe handling of radionuclide stipulated by the regulatory agencies. While the occupational workers are monitored by personnel monitoring devices, for general publics, it is not a regular practice. However, it can be achieved by using biomarkers with a potential for the radiation triage and medical management. An ideal biomarker to adopt in those situations should be rapid, specific, sensitive, reproducible, and able to categorize the nature of exposure and could provide a reliable dose estimation irrespective of the time of the exposures. Since cytogenetic markers shown to have many advantages relatively than other markers, the origins of various chromosomal abnormalities induced by ionizing radiations along with dose-response curves generated in the laboratory are presented. Current status of the gold standard dicentric chromosome assay, micronucleus assay, translocation measurement by fluorescence in-situ hybridization and an emerging protein marker the γ-H2AX assay are discussed with our laboratory data. With the wide choice of methods, an appropriate assay can be employed based on the net.

Keywords: Biomarker; Dicentric chromosomes; Fluorescence in-situ hybridization; Micronucleus.

Figure 1

Various biomarkers of ionizing radiation exposure. FISH: Fluorescence in situ hybridization; PCC: Premature chromosome condensation; ROS: Reactive oxygen species; ATM: Ataxia telangiectasia mutated.

Figure 2

Diagrammatic illustration on the formation of ionizing radiation induced chromosome aberrations.

Figure 3

General dose response relationship for chromosome aberrations induced by different types of ionizing radiations.

Figure 4

Metaphase chromosomes with (or) without dicentric chromosomes and dose response curve coefficients obtained from peripheral blood lymphocytes. AF: Acentric fragment; DC: Dicentric chromosome.

Figure 5

Binucleated cell with (or) without micronucleus and dose response curve coefficients obtained from peripheral blood lymphocytes.

Figure 6

Metaphase chromosomes with (or) without translocation and dose response curve coefficients after whole chromosome painting.

Figure 7

4’,6-diamidino-2-phenylindole, dihydrochloride stained nucleus with (or) without γ-H2AX foci and their coefficients obtained from peripheral blood lymphocytes.