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.

Endocardial tumors induced by carbamate or fluorenylacetamide derivatives in rats.

Endocardial tumors were induced in 18 rats treated with derivatives of carbamates and in 4 rats treated with derivatives of fluorenylacetamide. The endocardial tumor of 1 rat treated with N,N'-2,7-fluorenylenebisacetamide metastasized to the lung. This is the first report of metastasis of an endocardial tumor.

Comparative pulmonary tumorigenesis in DBA/2J and C57Bl/6J mice by administration of 3-methylcholanthrene and dimethylnitrosamine singly and combined.

C57Bl/6J mice, which are inducible for both hepatic and pulmonary aryl hydrocarbon hydroxylase (AHH), and DBA/2J mice, which are noninducible for hepatic AHH but moderately inducible for pulmonary AHH, received dimethylnitrosamine (DMN) i. p., or methylcholanthrene (MCA) orally, or a combination of both agents, for 10 weeks; the animals were observed for an additional 26 weeks.

Cancer associated with collagen-vascular disease.

Two cases of cancer, each associated with a different collagen-vascular disease, are reported. The first patient, a 71-year-old white man, had a history of acute dermatomyositis and malignancy for a few weeks only. Death was associated with adenocarcinoma of the lesser curvature of the stomach with metastases to the liver and beyond.

Adenocarcinoma of the gallbladder in guinea pigs.

Adenocarcinoma of the gallbladder developed in 17 of 68 untreated and in 26 of 83 irradiated guinea pigs of inbred strains 2 and 13. The carcinomas spread widely by direct extension and through lymphatic and blood vessels to lymph nodes, mesenteries, omenta, abdominal wall, liver, lungs, bones, and spleen. Whole-body exposure to gamma or X-radiation increased both the number of tumors and metastases in male inbred guinea pigs but not in females.

Angiosarcoma of the liver associated with diethylstilbestrol.

Angiosarcoma of the liver occurred in a 76-year-old man who had been treated for a well-differentiated adenocarcinoma of the liver with diethylstilbestrol for 13 years. Angiosarcoma was also present within pulmonary and renal arteries. The possibility that the intraarterial lesions might represent independent primary tumors is considered.

Differential effects of beta-naphthoflavone and pregnenolone-16alpha-carbonitrile on dimethylnitrosamine-induced hepatocarcinogenesis.

The effect of administration of beta-naphthoflavone (beta-NF) or pregnenolone-16alpha-carbonitrile (PCN) on the hepatocarcinogenicity of dimethylnitrosamine (DMN) in male SD rats was explored. Both beta-NF and PCN are potent repressors of the low Michaelis constant enzymatic form of DMN-demethylase, a mixed-function oxidase that catalyzes DMN demethylation. DMN-induced hepatocarcinogenesis was inhibited by PCN and was enhanced by beta-NF.

Enzymes in peripheral and bone marrow serum in patients with cancer.

Lactic dehydrogenase (LDH), glutamic-oxalacetic transaminase (GOT), and acid and alkaline phosphatase activities in bone marrow and in cubital vein serum were compared. For patients without cancer, marrow serum LDH attained levels four times as high, and GOT and alkaline phosphatase, levels twice as high as those normal for cubital vein serum; levels of acid phosphatase were the same for both sources. For patients with cancer, significant increase of enzyme levels over reference levels depends on the tumor origin and on the presence and localization of metastases.

Induction of carcinomas in the nasal cavity of rats by dioxane.

Six out of 120 rats fed dioxane in drinking water at levels of 0.75, 1.0, 1.