The present invention provides methods of inhibiting the development or progression of atherosclerotic, microvascular, or neurologic disease due to diabetes or insulin resistance in a mammal, or conditions resulting therefrom. The methods involve specifically inhibitingpoly(ADP-ribose) polymerase (PARP) activity or accumulation in the mammal. Also provided are antibodies that specifically react with N.alpha.-acetyl-N.delta. (5-hydro-5-methyl)4-imidazolone. Additionally, the invention provides methods of monitoring the effectiveness of an anti-diabetic or anti-insulin resistance treatment or an anti-diabetic or anti-insulin resistance complication treatment in a mammal. The methods involve measuring ADP-ribosylated protein levels, or measuring methylglyoxyl AGE levels in the mammal using an antibodies that specifically react with N.alpha.-acetyl-N.delta. (5-hydro-5-methyl)4-imidazolone, or measuring GlcNAc-modified protein levels in the mammal.