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Biomedical subjects

M Kuschner

Publications and source records attributed to M Kuschner.

At least 37 records · Page 2Linked to original sources
PubMed1980

Inhalation carcinogenesis by dimethylcarbamoyl chloride in Syrian golden hamsters.

The comparative carcinogenicity of dimethylcarbamoyl chloride (DMCC) was studies in male, Syrian Golden Hamsters by inhalation. Hamsters were exposed to 1ppm and the exposure periods were 6 hours per day, 5 days per week for the lifetime of the animals. Fifty-one percent of the hamsters developed carcinomas of the nasal tract. Morphologically, all of these tumors were classified as squamous cell carcinomas. In comparing the response of rats and hamsters at 1 ppm DMCC, the rat seems to show increased sensitivity and the percentage of tumor yield is almost doubled, with the tumors appearing much earlier in rats than in hamsters. However, the remarkable tumor yield in both species indicates the potent carcinogenic effects of DMCC.

Animals↗
PubMed1978

Histologic findings in the tracheobronchial tree of uranium miners and non-miners with lung cancer.

The remaining tissue of the tracheobronchial tree from 210 men who died from lung cancer was studied to compare the histologic alterations leading to further sites of primary cancer. These men were uranium miners matched with nonminers for age and smoking habits. In the examination of a total of 28,928 cross-sections carcinoma in situ was found in 96% of the miners and in 92% of the nonminers. The number of slides from miners showing degree 2 or 3 atypia in areas of carcinoma in situ was about double the number found from the nonminers. Although the difference was not statistically significant, 32% of the miners had at least one section showing early primary invasive carcinoma compared with 22% of the nonminers. The data indicate that the synergistic effect of the exposure to uranium dust along with cigarette smoking increases the risk of lung cancer and that in addition to a main tumor mass, other sites of tissue alterations leading to tumor development are frequently already present in the lung.

Adult↗
PubMed1975

Inhalation carcinogenicity of alpha halo ethers. I. The acute inhalation toxicity of chloromethyl methyl ether and bis(chloromethyl)ether.

A range of acute studies were performed with chloromethyl methyl either (CMME) and bis(chloromethyl)ether (BCME), including 14-day LC50's following single seven-hour inhalation exposures. The LC50's for CMME were 55 ppm for rats and 65 ppm for hamsters. The LC50's for BCME were 7 ppm for both species. All animals showed characteristic changes of acute irritation of the respiratory tract manifested by congestion, edema, and hemorrhage. Severe shortening of life span was seen in 30-day exposures of rats to CMME and in all studies with BCME. Incidences of mucosal changes, including atypia, were generally increased in a dose-related manner in both species. The carcinogenicity of BCME in these range finding experiments was demonstrated by a skin cancer in a rat after three exposures and a nasal tumor in a hamster after one exposure to 1 ppm BCME.

Animals↗
PubMed1975

Inhalation carcinogenicity of alpha halo ethers. II. Chronic inhalation studies with chloromethyl methyl ether.

Rats and hamsters were exposed to 1 ppm of chloromethyl methyl ether six hours per day, five days per week, throughout their lifetime. Mortality and weight gain of the exposed animals paralleled that of the control animals. Malignant tumors of the respiratory tract were found in two rats. These were a squamous cell carcinoma of the lung with blood vessel invasion and an esthesloneuroepithelioma originating in the olfactory epithelium and invading the forebrain. One hamster was found to have an adenocarcinoma of the lung and another, a squamous papilloma of the trachea. A single exposed rat had a pituitary tumor of primitive cell type that may well have been coincidental.

Adenocarcinoma↗
PubMed1975

Inhalation carcinogenicity of alpha halo ethers. III. Lifetime and limited period inhalation studies with bis(chloromethyl)ether at 0.1 ppm.

Rats and hamsters were exposed to 0.1 ppm bis(chloromethyl)ether (BCME) six hours per day, five days per week throughout their lifetime. Additional groups of rats were given 10, 20, 40, 60, 80, and 100 exposures to 0.1 ppm BCME and then held until death. Forty cancers originating in the respiratory tract were found in the 200 rats involved in these studies. These included 14 cancers of the lung and 26 cancers of the nasal cavity. They occurred in dose-related fashion. A single undifferentiated carcinoma of the lung was seen in a hamster.

Animals↗
PubMed1975

In vitro transformation of BHK21 cells grown in the presence of calcium chromate.

Concentrations of 0.25 and 0.5 mug/ml calcium chromate (CaCrO4-2H2O)dissolved in Dulbecco's medium were found to alter the growth behavior of BHK21 cells in culture. Treated cells grew as shortened fibroblasts and in random orientation. The changes detected during the first two weeks of culture in the presence of the metal became more pronounced as the number of growth passages increased. In addition to the alterations noted above, chromate-treated cells grew into large clusters in Methocel (an alternative technique to the agar suspension system), while untreated cells underwent, at most, only one or two divisions in Methocel. These alterations in growth properties were irreversible and persisted after removal of the treated cells from chromate-containing medium, suggesting that a heritable change had occurred as opposed to a transient, chromate-dependent alteration of cell growth. This experimental observation suggests that chromate salts and perhaps salts of other metals can transform BHK21 cells in vitro or can select for spontaneously transformed cells.

Animals↗
PubMed1975

The influence of varying lengths of glass and asbestos fibres on tissue response in guinea pigs.

Intratracheal injection of samples of naturally occurring and man-made mineral fibres into guinea pigs showed that while long fibre samples produced marked fibrosis, short fibre specimens produced only a macrophage reaction. In most cases the long fibre samples were administered in smaller doses than the short. The samples tested were crocidolite asbestos, a synthetic fluoramphibole and two specimens of glass fibre with different mean diameters. With all the minerals tested some short fibres, but not long fibres, were transported to the hilar lymph nodes. In some instances the numbers of short fibres found in these nodes appeared to be much higher than would be expected from the percentage of short fibres in the original sample, and it is suggested that this may be due to the breakdown of long fibres within the lung.

Animals↗