Spontaneous tumors and common diseases in two colonies of Syrian hamsters. IV. Vascular and lymphatic systems and lesions of other sites.

Spontaneous tumors were found in the vascular and lymphatic systems upon systemic histologic examination of the cardiovascular, hematopoietic, and lymphatic tissues of Syrian hamsters from the Eppley (EC) and Hannover colonies (HC). The incidence of endothelial tumors (hemangioendotheliomas) was similar in both colonies and sexes. The hemangioendotheliomas generally originated in the liver and spleen.

Spontaneous tumors and common diseases in two colonies of Syrian hamsters. III. Urogenital system and endocrine glands.

The frequency of spontaneously occuring neoplasms in the urogenital system and endocrine organs was examined in two Syrian hamster colonies [Eppley colony (EC); Hannover colony (HC)]. With the exception of a renal adenoma in an EC female, the urinary systems of animals in both colonies were free of neoplastic growths. A single epididymal adenoma of the male fenital system (EC) was found.

Spontaneous tumors and common diseases in two colonies of Syrian hamsters. I. Incidence and sites.

Syrian hamsters from two colonies [Eppley colony (EC); Hannover colony (HC)] were examined for spontaneous neoplastic and noneoplastic diseases. Significant differences were found in tumor incidence (30%, EC' 42%, HC), occurrence of malignant neoplasms (15%, EC; 32%, HC), appearance of multiple primary tumors in different organs (42%, EC; 30%, HC), average survival rates of tumor-bearing animals, organ distribution and histologic types, and average survival rates of all animals. The frequencies of nonneoplastic diseases also varied between the two colonies.

Spontaneous tumors and common diseases in two colonies of Syrian hamsters. II. Respiratory tract and digestive system.

Spontaneous respiratory tract neoplasms in Syrian hamsters occurred in almost equal frequencies in two colonies: 3% in the Eppley Colony (EC) and 3.6% in the Hannover Colony (HC). Neoplasms were in the nasal cavity, trachea, and lungs, and most were benign; however, 2 adenocarcinomas of the nasal cavity (EC) and 1 adenocarcinoma of the larynx (HC) were found.

Ultrastructure and formation of lamellated inclusion bodies in induced lung tumors of the European hamster.

Utlrastructure and formation of lamellated inclusion bodies (LB) in N-dibutyl-nitrosamine-induced lung tumors in European hamsters are described. Two types of LBs are observed: one with cross-barred lamellae and one with concentric lamellae. Both types develop from lysosome-like dense bodies which are formed by the Golgi apparatus.

Carcinogenic effects of different nitroso-compounds in Chinese hamsters. I. Dimethylnitrosamine and N-diethylnitrosamine.

Three hundred and twenty Chinese hamsters (Cricetulus griseus) (CH) were treated (s.c.) with 1/5, 1/10 or 1/20 LD50 of dimethylnitrosamine (DMN) or N-diethylnitrosamine (DEN).

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.

Carcinogenic effects of different nitroso-compounds in chinese hamsters: N-dibutylnitrosamine and N-nitrosomethylurea.

Three hundred and twenty Chinese hamsters (Cricetulus griseus) (CH) were subcutaneously (s.c.) treated with 1/5, 1/10 or 1/20 the mean lethal dose (LD50) of N-dibutylnitrosamine (DBN) or N-nitrosomethylurea (NMU).

Histogenesis of tumors from the nasal cavities induced by diethylnitrosamine.

Chronic subcutaneous (s.c.) or single intravenous (i.

The modification of the renal carcinogenicity of dimethylnitrosamine by actinomycin D and a protein deficient diet.

The effect of a single treatment with 30 mg dimethylnitrosamine (DMN) and 6 mug actinomycin D (ACT), given at different time intervals (ACT application to DMN, 2 h before, simultaneously, 5, 9 or 48 h later), was tested in female Sprague-Dawley rats in relation to renal carcinogenesis; additionally, the animals were fed either a normal or a protein deficient diet. The ACT treatment did not significantly modify either the kidney tumour incidence or the survival time in the different groups fed a normal diet. Nevertheless, there are indications that additional ACT application may shorten the latency period for DMN induced renal neoplasms or, when administered 5 h later than DMN, a slightly decreased and delayed tumour induction can be assumed.

Induction of pancreatic neoplasms by 2,2'-dioxopropyl-N-propylnitrosamine.

A high incidence of pancreatic duct adenomas and carcinomas were induced in Syrian golden hamsters as early as 13 weeks after chronic administration of 2,2'-dioxopropyl-n-propylnitrosamine (DOPN) at a 10 mg/kg dose. In contrast to another pancreatic carcinogen, 2,2'-dihydroxy-propyl-n-propyl-nitrosamine, DOPN induced no tumors of the upper respiratory tract or kidneys, and only a few neoplasms of the lungs and liver.

Transplacental effects of diethylnitrosamine in Syrian hamsters as related to different days of administration during pregnancy.

Female Syrian hamsters were given a single sc dose of 45 mg diethylnitrosamine (DEN)/kg body weight on 1 of the 15 days of pregnancy. In the offspring of females treated on 1 of the first 11 days of pregnancy, no respiratory tract tumors were found. The offspring of mothers given DEN on 1 of the last 4 days (12-15) of pregnancy developed respiratory tract neoplasms at a rate of up to 95%.

Specific carcinogenic effect of N-methyl-N-nitrosourea on the midventral sebaceous gland of the gerbil (Meriones unguiculatus).

Gerbils (Meriones unguiculatus), given N-methyl-N-nitrosourea iv once weekly for 15 weeks at doses related to the mean lethal dose, developed tumors of the species-specific midventral sebaceous gland. These neoplasms were more frequent in males than females and were histologically classified as sebaceous adenomas or carcinomas of varying differentiation.

The ultrastructure of N-dibutylnitrosamine induced pulmonary tumours (adenocarcinomata) in European hamsters.

N-dibutyl-nitrosamine induced pulmonary adenocarcinoma in European hamsters were studied electron microscopically. The tumours were composed of light and dark cells, which, due to their lamellar bodies, resembled alveolar epithelial cells Type II. As cells containing lamellar bodies also occasionally occurred with the epithelial lining of tumour associated peripheral bronchi, a possible bronchiolar origin of the neoplasms is discussed.

Effects of cigarette smoke on the bronchial epithelium of Syrian hamsters: ultrastructural studies.

The effects of two types of research cigarettes, which differed in their total smoke delivery and condensate, on the bronchial epithelium of Syrian hamsters were examined electronmicroscopically. The animals were exposed once a day for 5 days each week for 1 year to the total smoke of the cigarettes. Two groups and a control group were killed 1 day after the last exposure, and one group 12 months after the last exposure.

A new approach for induction of pancreatic neoplasms.

Weekly s.c. injections of equitoxic doses of 2-hydroxy-propyl-n-propylnitrosamine, 2-oxopropyl-n-propylnitrosamine, and methyl-n-propylnitrosamine, assumed metabolites of di-n-propylnitrosamine by beta oxidation, induced low incidences of pancreatic duct adenomas in Syrian golden hamsters.

Pancreatic neoplasms in an animal model: morphological, biological, and comparative studies.

After a short latency (15 weeks), a 100% incidence of pancreatic neoplasms was induced in Syrian golden hamsters, following the administration of 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN). Data extracted from reports of human pancreatic neoplasms were compared with findings relative to the induced neoplasms. The latter resembled human pancreatic tumors, in both biological and morphological aspects.

Inhalation experiments with 14C-labelled cigarette smoke. II. The distribution of cigarette smoke particles in the hamster respiratory tract after exposure in two different smoking systems.

Male and female Syrian golden hamsters were exposed to the smoke of [14C]dotriacontane-16,17 ([14C]DOT)-labelled cigarettes in 2 different exposure systems. These 2 systems differed in terms of the smoke concentration drawn into the exposure chamber. To compare the effectiveness of the exposure systems, the inhaled dose of 14C-labelled cigarette smoke was determined in the different parts of the hamster respiratory tract by liquid scintillation counting.

Inhalation experiments with 14C-labelled cigarette smoke. I. Determination of the effectiveness of two different smoking systems with labelled cigarettes.

Two different smoking systems were tested by exposing Syrian golden hamsters to the smoke of cigarettes labelled with (14C)dotriacontane-16, 17 (DOT). In 3 experiments, the activity of mainstream and sidestream Total Oarticulate Matter (TPM) and of butts and ash was determined. Comparing the results, the system involving individual exposure was shown to provide the animals with higher amounts of mainstream TPM than the system using simultaneous exposure of numerous animals.

Comparison of four different methods for the recovery of dotriacontane-16,17-14C from small animal respiratory tissue.

The efficiency and accuracy of four different methods of tissue preparation for the recovery of dotriacontane-16,17-14C (DOT-16,17-14C) from rat respiratory tissue were compared by means of liquid scintillation counting. A DOT-16,17-14C standard solution was placed on the respiratory epithelium of the nasal apex, larynx, trachea and main bronchi. Combustion of the lyophilized organs in a Packard sample oxidizer revealed the highest recovery and accuracy (93--100%), sample oxidizing by combustion without lyophilization the lowest recovery and accuracy (73--92%).

Comparative studies concerning the suitability of European hamsters and Syrian golden hamsters for investigations on smoke exposure.

The suitability of the European hamster and the Syrian golden hamster for experiments with tobacco smoke has been tested under various conditions by exposure of the animals to total smoke and the gas vapour phase of two cigarettes. Respiration rate, tidal volume and CO-Hb concentrations were measured before and after the exposures. The results demonstrate that the European hamster tolerates smoke inhalation under all conditions studied better than the Syrian golden hamster.

Comparative studies of blood from hibernating and nonhibernating European hamsters (Cricetus cricetus L).

The blood of 6 male and 6 female European hamsters (Cricetus cricetus L) was examined in summer, in winter before hibernation, and 1 da after awaking from hibernation. Blood was drawn from a sublingual vein under ether anesthesia in nonhibernating animals. No influence of hibernation upon the number of erythrocytes and the differentials was found, whereas the number of thrombocytes and leukocytes were reduced to a minimum.

Carcinogenic effects of Di-n-propylnitrosamine, beta-hydroxypropyl-n-propylnitrosamine, and methyl-n-propylnitrosamine on Sprague-Dawlay rats.

The carcinogenic effects of di-n-propylnitrosamine and its two related compounds, beta-hydroxypropyl-n-propylnitrosamine (HPPN) and methyl-n-propylnitrosamine (MPN), were tested in rats and compared. All three substances induced neoplasms in the nasal and paranasal cavities, esophagus, and liver. MPN treatment caused the highest tumor incidence in the esophagus, whereas HPPN induced the most hepatic tumors.