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Biomedical subjects

F Homburger

Publications and source records attributed to F Homburger.

At least 37 records · Page 2Linked to original sources
PubMed1979

Cigarette smoke inhalation studies in inbred Syrian golden hamsters.

Invasive carcinoma of the larynx was induced in 36.8% of inbred Syrian golden hamsters from strain B10 15.16, susceptible to this type of cancer when exposed to smoke from reference filter cigarettes for 59-80 weeks. Nearly half the animals (47.4%) showed laryngeal cancer, including noninvasive carcinoma and carcinoma in situ, which occurred with daily smoke exposures (twice a day for 12 min each time, for 27 sec out of each min) 7 days a week at smoke concentrations of 22%. When the smoke concentration was reduced to 11%, the number of induced lesions was reduced proprotionately. When a portion of tobacco was replaced in the cigarettes by a tobacco supplement, Cytrel (a trademark of the Celanese Corp., Charlotte, N.C.), a reduction of carcinogenesis proportionate to the Cytrel content of the cigarette took place. Smoke from cigarettes containing only Cytrel and no tobacco induced no carcinomas under the conditions used. Other dose-related changes observed were laryngeal papillomas, laryngeal epithelial hyperplasia, tracheal epithelial hyperplasia, and metaplasia and accumulation of alveolar macrophages. Tar deposition in lungs and accumulation of alveolar macrophages. Tar deposition in lungs and larynges was determined in a separate study by means of a marker, decachlorobiphenyl, added to the cigarettes. Admixture of Cytrel to cigarettes reduced tar deposition in the respiratory tract, which paralleled the decrease in the incidence of laryngeal carcinoma. However, the amounts of tar deposited in the larynx when 100% Cytrel was smoked were still significant, even though no carcinomas were observed. Thus smoke from Cytrel tobacco supplement may be less carcinogenic than equal amounts of tobacco smoke.

Animals↗
PubMed1978

An experimental approach to the breast cancer, reserpine problem.

Reserpine was administered intraperitoneally 3 times weekly to inbred female Syrian BIO hamsters of the 15.16 strain previously shown to be susceptible to methylcholanthrene (MC) induction of mammary cancer. Other groups of hamsters received non-carcinogenic doses of MC along with the reserpine administrations, and an additional group received a carcinogenic dose of MC alone. This last group demonstrated that BIO 15.6 females were indeed susceptible to MC mammary cancer induction, since 4 mg of MC administered by stomach tube (a total dose of 200 mg) caused mammary cancer in 52% of the animals. Mammary cancer was not observed in any of the animals given reserpine or reserpine in combination with the non-carcinogenic dose of MC.

Animals↗
PubMed1976

Mouse skin assay of condensate from smoking products other than tobacco.

The biologic activity of a smoking product other than tobacco (Cytrel) was compaed with that of an American-type blend of cigarette tobaccos by application of the smoke condensate (SC) to shaved mouse skin. In 4 nonsimultaneous experiments, SC's from the former were equivalent or lower in tumorigenicity than equal doses of those from the latter, studied simultaneously and under identical conditions; this was true for widely varying doses of SC's, ranging from 35 to 246 mg nonaqueous condensate (NAC) administered to each mouse/week for 63-92 weeks. The response to SC from smoking products other than tobacco ranged from a complete lack of epidermoid carcinomas and papillomas at the lower doses to an incidence of lesions in 25.3% of the animals at the highest dose. The SC from a typical American blend of tobaccos caused skin lesions in 18.7-39.1% of the animals. SC from type 324 Cytrel, applied at the even higher dose of 365 mg/mouse/week, caused papillomas or carcinomas in only 22.0% of the animals, as compared with 39.1% of mice after adminstration of 245 mg SC from the American blend of cigarette tobacco; this was the highest dose that could be achieved with a test material containing nicotine. SC from a 1:1 blend of Cytrel with cigarette tobacco produced considerably fewer skin lesions at the lower dose levels than did SC from tobacco. At the lowest dose of 35 mg/mouse/week, 2 and 18.7% of the animals had lesions, and at a 54-mg dose, 11.3 and 22.7% had lesions from the blend and tobacco samples, respectively. At an increased level (113 mg), the response was the same for the SC from a 1:1 blend and from cigarette tobacco. There existed an excellent dose-response relationship for SC from type 308 Cytrel tested at four dose levels: 8.4, 113, 246, and 383 mg NAC/mouse/week, with 0, 18.7, 25.3, and 57.7% of the animals exhibiting skin lesions, respectively. Based on the criteria inherent in the technique of "mouse skin painting", Cytrel variants appeared to be lower or equal in tumorigenicity than did cigarette tobacco.

Acetone↗
PubMed1976

Adenocarcinoma of the glandular stomach following 3-methylcholanthrene, N-nitrosodiethylamine, or N-nitrosodimethylamine feeding in carcinogen-susceptible inbred Syrian.

Invasive adenocarcinoma of the glandular stomach was induced in 3 BIO 87.20 inbred Syrian hamsters by the administration of 1 ppm N-nitrosodiethylamine or N-nitrosodimethylamine in the drinking water, and in 2 BIO 15.16 and 5 BIO 72.29 inbred Syrian hamsters by gavage of 3-methylcholanthrene. In contrast, many other similarly treated inbred Syrian hamster lines did not develop carcinoma of the glandular stomach. The glandular stomachs of rats and mice are resistant to polycyclic hydrocarcon carcinogenesis; however, the glandular stomachs of certain inbred Syrian hamsters develop adenocarcinoma after polycyclic hydrocarbon gavage. This work demonstrated the importance of genetic factors.

Adenocarcinoma↗
PubMed1975

Aging changes in CD-1 HaM/ICR mice reared under standard laboratory conditions.

Three hundred CD-1 HaM/ICR mice were observed for 2 years, and useful necropsies were done on 99 males and 102 females. Mortality was 50% at 16 months in the males and 18 months in the females. Among mice that came to autopsy, total tumor incidence was 54% for males and 75% for females, with most neoplasms occurring after 18 months. Adenomas or adenocarcinomas of the lung were the most frequent, followed by lymphoreticular tumors, vascular tumors, hepatomas, subcutaneous fibrosarcomas, and adenocarcinomas of the mammary glands. Some degree of amyloidosis was seen in half the mice of both sexes, beginning at 8 months in males and 12 months in females. Variability in tumor incidence among small groups if mice emphasized the need for adequate samples.

Adenocarcinoma↗
PubMed1975

"Smokers' larynx" and carcinoma of the larynx in Syrian hamsters exposed to cigarette smoke.

Several groups of investigators have recently produced carcinoma of the larynx in Syrian hamsters. This study reports on the effects of cigarette smoke from Kentucky reference cigarettes in an inbred strain (BIO 15.16) of Syrian hamsters. After "smoking" five days each week for two years, 20 percent of the surviving animals had cancer of the larynx; 40 percent had severe epithelial changes. These observations emphasize the role of cigarette smoke in the genesis of laryngeal cancer and respiratory tract cancer in general. An experimental method is now available for comparative studies of cigarettes and as a quide toward less hazardous smoking materials.

Animals↗