FIGURE 3.

Mean fold changes in average tail moments from baseline in peripheral blood cells for each subject. Tail moments correlated significantly with plasma zinc concentrations during the entire study period [A; days (d) 1–83] and during the zinc-depletion and -repletion period (C; d13–d83) but not during the baseline period (B; d1–d13). Multiple regression analysis was conducted to assess the association of change between variables with subjects as a factor. DNA single-strand breaks were measured by comet assay, and plasma zinc concentrations were measured by inductively coupled plasma optical emission spectrophotometry. Blood samples were collected on day 1 (beginning of the study), day 13 (baseline), day 35 (middle of zinc depletion), day 55 (end of zinc depletion), and day 83 (end of zinc repletion). Two comet slides were made for each human subject at each time point. Images of 100 randomly selected nuclei (50 nuclei from each of 2 replicate slides) were measured blindly for tail moment. There was a significant correlation between fold changes in average tail moments in peripheral blood cells and plasma zinc concentrations for the whole study period (P = 0.014) and the zinc-depletion and -repletion period (P = 0.0083) but no significant correlation for the baseline period (P = 0.67).