DESOXYRIBONUCLEIC ACID CONTENT AND CELL DENSITY IN BRAIN AND HUMAN BRAIN TUMORS

Abstract

The desoxyribonucleic acid (DNA) content per nucleus and per unit weight of tissue have been determined chemically in normal cerebral cortex, cerebellar cortex, and corpus callosum of man, dog, and cat and in various human brain tumors. Nuclear densities have been calculated from these determinations. Corpus callosum contains approximately the same total number of cells as does cerebral cortex; cerebellar cortex contains several times this number. The nuclear density in tumors is usually higher than in cerebral cortex or corpus callosum. The amount of DNA per nucleus in primary brain tumors is considerably higher than in normal tissue. The average DNA per nucleus in the more primitive and malignant tumors appears to be higher than in the more differentiated tumors. Calculations indicate that the increase in the DNA per nucleus in brain tumors is more likely to be due to polyploidy than to increased mitotic activity.