VARIABILITY IN CHROMOSOME-ABERRATIONS, SISTER-CHROMATID EXCHANGES, AND MITOGEN-INDUCED BLASTOGENESIS IN PERIPHERAL LYMPHOCYTES FROM CONTROLINDIVIDUALS

Confidence in results from monitoring genetic end points in environmen tally or occupationally exposed individuals can be improved with knowl edge of the normal variability of changes in genetic end points in the general population. Confounding effects can be determined, and study interpretation can be improved by correlation of this variability with various lifestyle factors such as sex and age, smoking and drinking h abits, viral infections, exposure to diagnostic X-rays, etc. Eight blo od samples were taken from each of 24 male and 24 female volunteers ov er a period of 2 years. Questionnaires pertaining to lifestyle were co mpleted at the time of each sampling. Whole blood was cultured and sli des prepared for chromosome abberration (CA) or sister chromatid excha nge (SCE) analysis. Separated mononuclear cells were cultured with a r ange of phytohemagglutinin concentrations, and the maximum level of mi togen-induced blastogenesis was determined by measurement of [H-3]thym idine uptake. There was a significant effect of both year and season o f sampling for all three end points. Because there was no consistent p attern in 2 successive years, effects were thought to be independent o f season. No significant effects in any of the three end points were f ound with respect to sex or age nor any of the other lifestyle factors , although SCE frequency and mitogen-induced blastogenesis were nearly always higher in females than in males. These results point to the ne ed for concurrent sampling of controls with exposed populations.