*Lane 1, untreated control A Hind III-digested DNA in pH 7.4 phosphate buffer; lane 2, same as lane 1 but with 2 mM Cr(IV) added; lane 3, same as lane I but with 0.2%H202 added; lane 4, incubation mixture containing DNA, 2 mM Cr(IV) and 0.2% H20,; lane 5, same as lane 4, but with 5000 waits/m1 catalase added; lane 6, same as lane 4, but with 2 mM deferoxamine added; lane 7, same as lane 4 but with 50 mM sodium formate added; lanes 8-11, same as lane 4, but with 0.1, 1, 2, and 5 mM aspirin added. The samples were incubated for 8 hr.