Histochemical Studies of Experimentally Produced Bovine Fibropapillomas**From the Department of Veterinary Science, College of Agriculture and Life Science, The University of Wisconsin, Madison, Wisconsin 53706.

Abstract

ABSTRACTExperimentally produced bovine fibropapillomas could be divided into the stages of inflammatory reaction, fibroplasia, acanthosis, papillomatosis and regression. In the stage of papillomatosis, characteristic clear or vacuolated cells developed intranuclear inclusion bodies which had a DNA type of fluorescence with euchrysine stain, were Feulgen positive, and consisted of aggregations of bovine papilloma viruses.There was prominent enzyme activity of DPNH-diaphorase, TPNH-diaphorase, cytochrome oxidase, succinic dehydrogenase, and esterase in the hyperplastic epithelial cells of the acanthotic stage. These enzyme activities decreased progressively toward the keratinized layer in the stage of papillomatosis and regression. Proliferating fibroblasts in the dermis exhibited intense activity of cytochrome oxidase, DPNH-diaphorase, TPNH-diaphorase, succinic dehydrogenase, aminopeptidase, alkaline phosphatase, and nonspecific esterase. These enzyme activities decreased gradually as fibroblasts matured to fibrocytes in the stages of papillomatosis and regression