title: Appearance of ear tumors in Sprague-Dawley rats treated with 1,2-dimethylhydrazine when used as a model for colonic carcinogenesis.
abstract: One of the models of colon carcinogenesis in rats is produced by s.c. injections of 1,2-dimethylhydrazine (DMH). This specific colon carcinogen provokes other tumors in the rat, notably intestinal tumors. Ear tumors are just marginally mentioned in the literature. We have studied the appearance and histologic characteristics of ear tumors produced by 19 s.c. injections of 21 mg/kg of DMH in 18 Sprague-Dawley rats: 15 tumors appeared in 13 ears of 10 rats (55% of the animals). Simultaneously there were 23 colonic tumors: four (26.6%) of the tumors were carcinomas, 10 (66.6%) papillomas and one (6.6%) pseudoepitheliomatous hyperplasia. We conclude that ear tumors induced by DMH appear in 55% of the rats and that it is not possible to distinguish macroscopically in terms of size and aspect between benign and malignant lesions.
authors.affiliation: Department of Medicine and Surgery, Faculty of Medicine, Estudi General de Lleida, University of Barcelona, Catalonia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Viñas-Salas
authors.forename: J C
authors.initials: JC
authors.lastname: Fortuny
authors.forename: J
authors.initials: J
authors.lastname: Panades
authors.forename: C
authors.initials: C
authors.lastname: Piñol
authors.forename: M
authors.initials: M
authors.lastname: Prim
authors.forename: A
authors.initials: A
authors.lastname: Fermiñan
authors.forename: G
authors.initials: G
authors.lastname: Corbella
authors.forename: J
authors.initials: J
authors.lastname: Calderó
authors.forename: R
authors.initials: R
authors.lastname: Egido
mesh_terms: D019813:1,2-Dimethylhydrazine; D000818:Animals; D002273:Carcinogens; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced / Q000473:pathology; D003110:Colonic Neoplasms / Q000139:chemically induced*; D004127:Dimethylhydrazines; D004423:Ear / Q000473:pathology; D004428:Ear Neoplasms / Q000139:chemically induced* / Q000473:pathology; D004431:Ear, External; D006965:Hyperplasia / Q000139:chemically induced; D010212:Papilloma / Q000139:chemically induced; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002273:Carcinogens; D004127:Dimethylhydrazines; D019813:1,2-Dimethylhydrazine