cytotoxicity , as measured by cell-plating efficiency , correlates linearly with the level of dna breakage induced by both agents ( hgcl2 , r = 0.97 ; x-rays , r = 0.99 ) , although a substantial difference in axis intercepts of the two linear regression lines indicates that a higher level of dna damage was required by x-rays as compared with hgcl2 to produce an equivalent level of cell killing .
C0012854
dna
C0000702
a