the various liquid scintillation counting-based unscheduled dna synthesis assay procedures were examined according to the following groupings : ( 1 ) procedures based on the acid precipitation of cellular macromolecules , ( 2 ) procedures based on isopycnic gradient centrifugation of solubilized cells , ( 3 ) procedures based on nuclei isolation in conjunction with other dna purification methods , and ( 4 ) procedures based on the selective retention of hepatocellular dna .
C0007634
cells
C0007610
nuclei