DNA concentrations in the human cerebellum. Computation from kinetics of deoxyribose extraction in hot acid

: DNA can be measured in mammalian tissues by extracting deoxyribose from unfixed, lyophilized tissue specimens with 0.5 N perchloric acid at 90 degrees C. Deoxyribose concentrations in the extract are determined photometrically by reaction with diphenylamine. Inevitably, some deoxyribose is destroyed during exposure to the hot acid. A computer program has been written which corrects photometric absorbance data for such loss of deoxyribose. When extrapolated to infinite duration of extraction, the corrected absorbances yield a measure of the DNA content of the specimen. This method was used to estimate DNA concentrations in human cerebellar cortex and white matter. The results are discussed in relation to stable carbon isotope ratios of human cerebellar DNA.