it was found that treatment of cells irradiated early in cell cycle , that is , in g1 and early s , with apc or ara-c in g2 , ( 1 ) reduced the frequency of chromatid and chromosome exchanges below that of cells treated with x-rays alone , ( 2 ) produced no more chromatid breaks and gaps than were seen in unirradiated cells , ( 3 ) increased the number of chromosome fragments and gaps in a more than additive fashion , and ( 4 ) produced only an additive effect , by comparison with the effect of x-rays and drug given separately , on the total number of chromosomal aberrations .
C0008545
chromatid
C0007634
cells