M.B. Ketkar

A chronic study of praziquantel in syrian golden hamsters and Sprague-Dawley rats

Groups of Syrian golden hamsters and Sprague-Dawley rats received 100 mg or 250 mg praziquantel/kg body weight, intragastrically by oral gavage once weekly for 80 weeks and 104 weeks, respectively. In both hamsters and rats the observed differences in tumour incidence, latency and multiplicity revealed no positive dose response effect. Tumours observed corresponded in their origin and morphology to those which develop spontaneously in these species. Haematological and clinico-chemical values were normal. Whereas the average survival time was slightly shortened in rats, female hamsters showed reduced weight gains in the high dose level groups, although water intake and food consumption were increased.

The carcinogenic effect of nitrosomethyldodecylamine in European hamsters

Laboratory-bred European hamsters received nitrosomethyldodecylamine (NMDA) subcutaneously in olive oil once weekly for life. The animals showed mainly mucoepidermoid carcinomas of the lung, carcinomas of the urinary bladder and squamous cell carcinomas and sarcomas at the injection site. The tumour incidence was 90% in males and 70% in females, while the average tumour latency was 32 +/- 6 weeks for both sexes. Males had an average survival time of 29 +/- 17 weeks and females 24 +/- 19 weeks.

Comparative study of the carcinogenic effect of BHP and BAP on NMRI mice.

The carcinogenic effects of N-bis(2-hydroxypropyl)nitrosamine (BHP) and N-bis(2-acetoxypropyl)nitrosamine (BAP) were studied in NMRI mice treated subcutaneously once weekly for life. The highest incidences of tumours were found in the lung (73-100%), in the liver (67-100%) and nasal cavity (0-33%) in both sexes of mice. Data were similar in animals treated with BHP or BAP. These tumours were adenomas, adenocarcinomas and squamous cell carcinomas (nasal cavity and lung) as well as hemangio-endotheliomas and hemangioendotheliosarcomas (liver). The lung tumours were found in the control mice (27-50%) 20 weeks later than in the experimental animals. The rate of malignant neoplasms rose with increasing survival and decreasing dose levels.

Investigations on the carcinogenic burden by air pollution in man. Intratracheal instillation studies with benzo(a)pyrene in bovine serum albumin in Syrian hamsters.

The chronic effect of benzo(a)pyrene (B(a)P) administered intratracheally in bovine serum albumin was studied in Syrian golden hamsters. Dose levels of 0.1 mg, 0.33 mg and 1.0 mg of B(a)P induced papillomas and carcinomas of the trachea, stem bronchi and bronchioles. In addition to such tumours, the mucosa of the respiratory tract revealed a variety of atypical epithelial alterations. Although survival time exhibited a dose-dependency, tumour incidence did not. The incidence of respiratory tract tumours was higher in female hamsters than in males. The results of these investigations are statistically evaluated.

The carcinogenic effect of dimethylnitrosamine in laboratory bred european hamsters (cricetus cricetus)

The carcinogenic effect of dimethylnitrosamine (DMN) s.c. injected at two different dose levels was studied in laboratory bred European hamsters (EH) and data compared to findings for captured EH. Malignant haemangioendotheliomas of the liver and kidney, hepatocellular carcinomas and cholangiocarcinomas were induced. In contrast to the results obtained with wild EH, a large number of the laboratory bred females additionally developed ovarian granulosa cell tumors.

The carcinogenic effect of bis-(2)-oxopropyl)-nitrosamine on Sprague-Dawley rats

Sprague-Dawley rats received subcutaneous injections of bis-2-oxopropyl)-nitrosamine (BOPN) once weekly for life. The animals developed mainly papillomas and squamous cell carcinomas of the nasal cavity, follicle cell carcinomas of the thyroid gland and papillomas and transitional cell carcinomas of renal pelvis, ureter and urinary bladder. The tumour incidence was 100% in all the 3 treated groups. Survival time, tumour latency and multiplicity showed dose dependency.

The carcinogenic effect of 1,1-diethyl-3-methyl-3-nitrosourea in Syrian golden hamsters

1,1-Diethyl-3-methyl-3-nitrosourea (Et2MNU) was subcutaneously injected in Syrian golden hamsters once weekly for 52 weeks. The animals developed mainly papillomas and squamous cell carcinomas of the nasal cavity and forestomach and hemangioendotheliomas of the spleen. Although survival time and tumour latency showed dose-dependency, tumour incidence did not.

The chronic effects of magenta, paramagenta and phenyl-β-naphthylamine in rats after intragastric administration

Abstract Sprague-Dawley rats received intragastric administration of magenta, paramagenta or phenyl-β-naphthylamine (P-2-NA), twice weekly for life. No tumours could be found which were associated with the treatment.

Carcinogenic effect of nitrosomorpholine administered in the drinking water to Syrian golden hamsters

The long term carcinogenic effect of nitrosomorpholine (NM) was tested in Syrian golden hamsters (Mesocricetus auratus W.). Groups of 30 females and 30 males were given 0.010%, 0.005% and 0.001% NM in their drinking water. The animals developed neoplasms in the larynx, and trachea (papillary polyps, papillomas and epidermoid carcinomas) and in the liver (hepatocellular adenomas and carcinomas). In addition to these, cholangiocellular and endothelial liver tumours were observed. The overall tumour frequency was dose dependent.

Investigations on the carcinogenic burden by air pollution in man. Intratracheal instillation studies with benzo[a]pyrene in a mixture of Tris buffer and saline in Syrian golden hamsters*

Syrian golden hamster received intratracheal instillations of 0.125, 0.25, 0.50 or 1.0 mg benzo[a]pyrene (B[A]P) in a mixture of Tris buffer and physiological saline once weekly for life. Papillary polyps, squamous cell papillomas and carcinomas developed in both the larynx and trachea. In addition, bronchiogenic adenomas, adenocarcinomas and squamous cell carcinomas were induced in the lung. The highest incidence of respiratory tract tumours (83%) was seen in hamsters receiving 0.25 mg B[a]P. The results of these investigations are statistically evaluated and discussed.