Mammary gland tumors in irradiated and untreated guinea pigs.

This is a report of mammary gland tumors from 62 guinea pigs. The tumors arose in the terminal ductal-lobular units as either lobular acinar carcinoma or cystadenocarcinoma or as papillary carcinomas within large ducts near the mammilla. About half the number of the males had terminal ductal-lobular carcinomas and all but 2 of the papillary duct carcinomas also arose in males.

Comparative pathology of cardiac neoplasms in humans and in laboratory rodents: a review.

This review deals with the frequency, heredity, and morphology of 19 different histologic types of cardiac tumors that may affect humans, rat, mouse, guinea pig, and mastomys. Chemicals, durable fibrous materials, viruses, and probably irradiation have induced cardiac tumors in rodents. Apart from the involvement of asbestos in the induction of pericardial mesothelioma, no carcinogens have been identified in induction or promotion of cardiac tumors in humans.

Tumor induction in Praomys (Mastomys) natalensis by N,N'-2,7-fluorenylenebisacetamide.

Feeding N,N'-2,7-fluorenylenebisacetamide (CAS:304-28-9) at 0.025% to 15 male and 15 female mastomys considerably shortened their life-span. At death every treated mastomys had several primary tumors; untreated animals at comparable ages had none.

Cardiac tumors of mice.

Of the 7 primary tumors of the mouse heart, accessed at the Registry of Experimental Cancers, 3 were mesenchymal cell sarcomas, 3 were hemangioendotheliomas, and 1 was a mesenchymoma. The mesenchymal cell sarcomas metastasized via the bloodstream to lungs, kidneys, and spleen. Five of the tumors arose in mice treated with ionizing radiation.

Endocardial tumors in rats exposed to durable fibrous materials.

Endocardial tumors in the rat found in association with intrathoracic implantation of durable fibrous materials are reported here for the first time. In Osborne-Mendel female rats, endocardial tumors occurred in 3 of 50 rats associated with the implantation of fiberglass greater than 5 micron in length and 1-3 micron in diameter, in 1 of 15 rats associated with fiberglass of 0.03 X 3 micron, and in 1 of 15 rats associated with pulverized glass fiber.