Reduction of papilloma size by ultraviolet irradiation in the Japanese newt, Cynops pyrrhogaster.
Experiments were conducted on 44 captive Japanese newts (Cynops pyrrhogaster) to test the hypothesis that ultraviolet (UV) irradiation might inhibit growth or induce regression of spontaneous skin papillomas of probable viral origin. An empirically derived exposure to UV irradiation (42 microW per cm2 per day) induced reduction of papilloma size which began approximately 4 weeks after irradiation was initiated. This regression included histological evidence of tissue vacuolization and cellular necrosis of papillomatous epithelium. These findings, taken together with previous data on seasonal, temperature and geographical influences on papilloma prevalence, lend support to the notion that solar UV radiation may modulate papilloma prevalence in the natural environment, possibly by direct effects on viral infection.
Oka
K
K
Department of Biology, School of Medicine, Tokyo University, Japan.
Kishi
K
K
Shiroya
T
T
Asashima
M
M
Pfeiffer
C J
CJ
D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000473:pathology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D008297:Male; D010212:Papilloma / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D012455:Salamandridae; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D014466:Ultraviolet Rays