Enhancement of the biological activities of deoxyribonucleic acid extracted from canine venereal tumours.

Deoxyribonucleic acid (DNA) extracted from canine venereal tumours was capable of changing normal cells to morphologically abnormal cells in an in vitro system of L-fibroblasts. The observed effects were proportional to the concentration of the nucleic acid extract used; the higher the concentration, the more pronounced the effect. Inactivation of this effect by deoxyribonuclease indicated that the active nucleic acid moiety was DNA. Purified RNA did not appear to contribute to the observed activity. The activity was enhanced by diethyl-amino ethyl-dextran (DEAE-D) and dimethyl sulphoxide (DMSO) and the data showed that 20% DMSO was superior to 300 g/ml DEAE-D as an enhancing agent.