Investigations on the carcinogenic burden by air pollution in man. XVIII. The morphology of neoplasms induced in NMRI Mice after subcutaneous administration of PAH (individual or combination treatment).

A single s.c. dose of polycyclic aromatic hydrocarbons (PAH) administered individually or in combinations in the neck area to NMRI mice produced mainly malignant mesenchymal neoplasms at the injection site.

Inhalation studies with polyurethane foam dust in relation to respiratory tract carcinogenesis.

Male and female Sprague-Dawley rats were exposed to freshly generated polyurethane foam dusts, in concentrations averaging 8.65 mg/m3 air, for 6 hours daily 5 days a week over a period of 12 weeks. For comparison the same numbers of rats were exposed to titanium dioxide (TiO2) (15.

Induction of pancreatic duct of carcinomas in the Syrian hamster with 2,6-dimethylnitrosomorpholine.

Pancreatic duct carcinomas were induced in Syrian hamsters by intragastric administration of 2,6-dimethylnitrosomorpholine. As early as 30 weeks after treatment began, tumors were macroscopically visible in the pancreas; the maximum incidence of such tumors reached 71% by the end of the experiment. They were ductal in origin, and some metastasized to the lung.

Intrasplenic tumor formation in the syrian hamster (Mesocricetus auratus) after tracheal implants and treatment with diethylnitrosamine.

In two simultaneous experiments (A and B), tracheal tissue from 25 young Syrian hamsters was implanted in their mothers' spleens. In A, after tracheas from 3-week-old untreated donor offspring were implanted into their mothers, the mothers received 18 mg diethylnitrosamine (DEN)/kg body weight, sc, twice weekly for 20 weeks. Thereafter, the implants were removed and transferred to the spleens of other untreated offspring that were then similarly treated with DEN for 20 weeks.

[Halothane on irradiated liver tissue].

The results of animal experiments show that distinction must be made between acute and chronic tissue changes produced by irradiation of the liver. The pathologico-morphological findings obtained by irradiation of the liver combined with repeated halothane administration during short-term experiments are scanty and dosage-dependent. Long-term observation has revealed higher-dosage irradiation to be followed by minor inflammation which, if combined with regular halothane administration, progresses to produce the patho-anatomical picture of chronic hepatitis with diffuse cell damage and focal necrosis even in those groups of animals which had been exposed to low-dosage irradiation.