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.

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. The findings indicated a need for precise histologic evaluation to generate information for comparative purposes regarding the use of hamsters in experimental pathology and carcinogenesis studies.

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. However, incidences of female genital tract tumors were 10 (EC) and 3.5% (HC) and accounted for 34 and 11%, respectively, of all tumors in females. Among all genital tract tumors, 3 (EC) and 57% (HC) were ovarian, 14% (HC) were in the fallopian tubes, 81 (EC) AND 29% (HC) were uterine, and 16% (EC), vaginal. The overall incidence of endocrine organ tumors was similar in both colonies (EC, 22%; HC, 19%). The distribution of these tumors was as follows: pituitary gland; EC, 3%, HC, 0; thyroid gland: EC, 28%, HC, 31%; parathyroid gland: EC,11%, HC, 18%; adrenal cortex: EC, 42%, HC, 31%; adrenal medulla: EC, 7%, HC, 0; and endocrine pancreas: EC, 10%, HC, 31%. The morphology of these neoplasms is described and the incidence compared with those reported in other colonies.

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. Malignant lymphomas developed in high incidences in both colonies; however, their morphology varied. Those in EC hamsters were of histiocytic and, to a lesser extent, plasmacytic types; in the HC lymphocytic and epithelioid cell types were also found. Among tumors of miscellaneous sites, Harderian gland adenomas occurred in almost equal frequencies in EC and HC hamsters, but predominated in males. Tumors of the bone and soft tissue were present only in EC hamsters, whereas skin neoplasms developed solely in HC hamsters.

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. The incidence of digestive tract tumors showed a more marked difference than that of the respiratory tract: 7% in the EC and 23% in the HC. Digestive tract tumors accounted for 15 and 41% of all tumors in the EC and HC, respectively. All EC digestive tract neoplasms were benign and occurred mostly in males; 19 (83%) were forestomach papillomas and the remaining 4 )17%) were liver hemangioendotheliomas (2) and pancreatic duct adenomas (2). In the HC, almost 50% of the digestive tract neoplasms were malignant and most frequent in females. These tumours include 19(42%) intestinal adenocarcinomas, 18(40%) liver neoplasms (hemangioendotheliomas, cholangiomas, cholangiocarcinomas), 5 (13%) forestomach papillomas, and 2 (4%) gallbladder polyps. The morphology of these neoplasms was reported.

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). In several respects these two substances produced the same organotropy in the CH as in the Syrian golden (SGH) and European hamsters (EH). DBN prolonged lung tumours and neoplasms of the injection site. NMU induced tumours of the injection site only.

Inhalation experiments with 14C-labelled cigarette smoke. III. Body size dependent distribution of particulate matter in small rodents during cigarette smoke inhalation.

Syrian golden and European hamsters were exposed to 14C-labelled cigarette smoke. The deposition of the 14C activity in the respiratory and digestive tracts was determined immediately after the exposure. From the results obtained it can be seen that the distribution of particulate matter between the upper and lower respiratory tract, as well as, between the respiratory and digestive tracts is related to the body weight of the experimental animals.

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.

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. About 6 times more smoke particles were deposited in the respiratory tract after exposure to high smoke concentration with intermittent puffs of fresh air (closed system) than after exposure to smoke diluted with air (open system). About 80% of the diluted smoke reached the bronchi and lung compared to approximately 60% of the concentrated smoke. The remainder of the dose was trapped in the upper respiratory tract, mainly by the nose and larynx. Additionally, in the open system the total dose of inhaled smoke was dependent upon the position in the exposure chamber. The results are discussed with respect to the use of the exposure systems for chronic cigarette smoke inhalation studies in experimental respiratory tract carcinogenesis.

[Animal model for the etiopathogenesis of sialadenitis].

A longitudinal study with patient-specific jaw models and simultaneous X-Rays was undertaken to examine the eruption behaviour of the mandibular premolars following physiological and pathological resorption of the roots of primary teeth. 1. The molars of the first dentition fall out earlier after pathological resorption of the roots of primary teeth. In the presence of an occlusal bony bridge the appearance of a new tooth may take years. The eruption of the replacing tooth is delayed or it may be retained. 2. The eruption times of premolars after physiological resorption of primary tooth roots given in the literature and those obtained by the author converge. After pathological resorption of primary tooth roots and rarefying osteitis with interruption of the lamina dura, vertical development occurs significantly sooner (p less than 0,01). 3. The sequence of eruption of the premolars can be altered after pathological resorption of primary tooth roots.

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). These substances, in several respects, showed a different organotropy in this species than in both the Syrian golden (SGH) and the European hamster (EH). In CH, DEN produced up to 100% squamous cell papillomata and occasionally also carcinomata of the cheek pouch, tongue, pharynix, oesophagus and forestomach. With DEN a high rate of hepatomata was simultaneously realized. DMN induced a considerable quantity of liver tumours, the highest incidence being demonstrated in the lowest dosage group.

Susceptibility of gerbils (Meriones unguiculatus) to weekly subcutaneous and single intravenous injections of N-diethylnitrosamine.

Weekly s.c. (24, 12, and 6 mg/kg b.w.) or a single i.v. (100 or 50 mg/kg b.w.) injections of N-diethylnitrosamine (DEN) to gerbils (meriones unguiculatus) resulted in tumours of the respiratory tract and liver. Carcinomata of the nasal olfactory region or respiratory-olfactory mucosal junction were most common; papillomata of the tracheobronchial system and adenomata or carcinomata of the lungs appeared in significantly lower incidences. The neoplasms of the liver were of cholangiocellular and in a few cases of hepatocellular origin.

Carcinogenic effects of different nitroso-compounds in Chinese hamsters. II. N-nitrosomorpholine and N-nitrosopiperidine.

A total of 320 Chinese hamsters (Cricetulus griseus) (CH) were subcutaneously (s.c.) treated with 1/5, 1/10, or 1/20 LD50 of N-nitrosomorpholine (NM) or N-nitrosopiperidine (NP). In the CH, NM and NP both produced up to a 100% rate of papillomas of the cheek pouch, tongue, pharynx, esophagus and forestomach. Occasionally squamous cell carcinomas also developed in these organs. A high rate of hepatomas was realized by NP.

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%). Tissue solubilization by the commercially available tissue solubilizer TS-1 revealed a better recovery and accuracy (89--95%) than tissue maceration by boiling in methanolic KOH and toluene extraction (74--91%). Depending on the laboratory equipment, lyophilization or tissue solubilization is preferred; maceration and toluene extraction as well as combustion without freeze-drying are disregarded for further investigations because of the cumbersome procedure as well as the low recovery and accuracy, respectively.

Carcinogenic effects of skin transplantation and immunosuppression in mice.

C3H and BlD2 mice received skin transplants from an animal of the other strain. Three groups were immunosuppressed for varying periods of time, and with different doses of vinblastine, cyclophosphamide, or azathioprine. Following transplantation, control animals received daily injections of NaCl. All animals developed tumours of lymphoreticular origin, which would indicate that immunosuppression is only a secondary cause for tumor development, with antigenic stimulation being the primary factor.

[Benzopyrene (BaP) implants into the glottic mucous membrane of hamsters]. / Benzpyren (BaP)-Implantate in die Glottisschleimhaut beim Feldhamster.

For testing the effect of benzo (a) pyrene (BaP) on glottical epithelium European hamsters were used. With laryngofissure hamsters larynges had been opened and a mixture of tricaprilin, beewax and 1 mg BaP was implanted into a pocket formed by mucous membrane of one vocal fold. Compared to typical histology in smoker's larynx, squamous metaplasia and dysplasia and in one case papillary polyps could be described. No squamous cell carcinomata was found.

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. In groups fed a protein deficient diet, a significantly higher percentage of kidney tumour bearing animals as well as a shortened latency period were found when compared with the DMN group on normal diet, but these differences were independent of the additional ACT treatment 9 h later than DMN and were due to the protein deprivation. Morphologically, the tumours were of epithelial and mesenchymal type with a clear preponderance of the former type. Biochemical and morphological aspects are discussed.