ALKALINE SINGLE-CELL GEL-ELECTROPHORESIS OF DNA FRAGMENTS IN BIOMONITORING FOR GENOTOXICITY - AN INTRODUCTORY STUDY ON HEALTHY-HUMAN VOLUNTEERS

Alkaline single cell gel electrophoresis (also known as the 'comet ass ay') is a rapid method for detecting DNA strand breaks in individual c ells. Before the assay is used for biomonitoring in human populations the test conditions must be accurately characterised. Five healthy mal e volunteers donating capillary blood over a period of 20 weeks showed a fairly stable level of DNA damage in their lymphocytes. The values for tail moment and tail inertia, as evaluated by computerised image a nalysis of coded samples, were similar to those in lymphocytes from co ntrol mice but only 10% of those in lymphocytes from mice given cyclop hosphamide (200 mg/kg b.wt.) 15-17 h before sacrifice. Inter- and intr aindividual variations among the human subjects were related to both i ndividual factors and laboratory conditions. When the comet assay is u sed for biomonitoring purposes it is suggested that each electrophores is session should include not only the coded samples from the subjects , but also freshly isolated control cells and, in addition, cells that have been exposed to a well-characterised genotoxic insult.