THE SINGLE-CELL GEL-ELECTROPHORESIS COMET ASSAY - A POTENTIAL TOOL FOR DETECTING RADIATION-INDUCED DNA-DAMAGE IN HUMANS

This review evaluates the applicability of the single cell gel (SCG)/c omet assay as a tool for the biomonitoring of individuals accidently, environmentally or occupationally exposed to ionizing radiation, This technique detects single-strand DNA breaks, alkali-labile damage, inco mplete excision repair sites and DNA:DNA crosslinking at the level of the individual cell, The advantages of this technique include: (a) dat a are collected at the level of the individual cell, providing informa tion on the intercellular distribution of damage and repair; (b) only small numbers of cells are required (i.e., only a few thousand); (c) v irtually any eukaryotic cell population can be used; and (d) the assay is relatively sensitive (detection limit of 5 cGy gamma rays in human lymphocytes), simple and cost effective, What the assay lacks is spec ificity for radiation-induced DNA damage, However, the possibility of identifying types of DNA damage specific for ionizing radiation in sel ected subtypes of cells may be feasible, While additional research is required before the SCG assay can readily be applied as a standard bio monitoring tool for exposure to ionizing radiation, the data collected thus far support a conclusion that such research is clearly warranted .