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Biomedical subjects

H Reznik-Schüller

Publications and source records attributed to H Reznik-Schüller.

At least 19 recordsLinked to original sources
PubMed1980

Atrophy induced in the tubules of the testes of Syrian hamsters by two retinoids.

This paper describes toxic lesions induced in the hamster testes by 3 different retinoids. Groups of 13 Syrian Golden hamsters were fed diets containing 120 mg/kg 13-cis-retinoic acid (CRA), 327 mg/kg ethyl retinamide (ER), or 343 mg/kg 2-hydroxyethyl retinamide (HER) for 6 months. The germinal epithelium of the testicular tubules was completely atrophic in the groups fed ER and HER. Mean testicular weights were 0.8 g and 0.7 g respectively as compared to 3.3 g in the control group. No alterations in testicular weights or morphological characteristics, at the light microscopic level, were found in the group fed CRA. At the ultrastructural level, however, asymmetrical head caps and deformed acrosomes were observed in the spermatids.

Animals↗
PubMed1980

A morphometric study of the pulmonary Clara cell in normal and nitrosoheptamethyleneimine-treated European hamsters.

Previous studies have identified the bronchial Clara cell as the progenitor of the lung tumors induced in European hamsters by nitrosoheptamethyleneimine (NHMI). Using stereological methods, we compared the ultrastructure of Clara cells from untreated animals and lung tumor cells, induced by NHMI, in the European hamster. The composition and volume of the cytoplasm was significantly altered in the tumor cells whereas the nuclei did not show any measurable changes in size or structure when compared with the controls.

Animals↗
PubMed1980

Morphology of nasal-cavity tumours in rats after chronic inhalation of 1,2-dibromo-3-chloropropane.

Groups of 50 F344 rats of each sex sere exposed to 0.6 or 3.0 pts/10(6) of 1,2-dibromo-3-chloropropane (DBCP) by inhalation for 6 h/day, 5 days/week for 103 weeks. Fifty rats of each sex inhaling filtered air were used as unexposed controls. All survivors were killed at 104 weeks. Up to 93% of the male and female rats developed neoplasms of the nasal cavity. Most of the tumours were adenomas, squamous-cell papillomas, squamous-cell carcinomas, and adenocarcinomas. In the low-dose group 78% of the tumours in males and 66% in females were benign, whereas in the high-dose groups 89% in males and 76% in females were malignant. Invasion through the cribriform plate into the cerebrum or metastasis to the regional lymph nodes was found in 73% of the carcinomas in males and 51% in females. Electron-microscopic examination suggested that the basal cells of the olfactory epithelium were the site of origin of the poorly differentiated adenocarcinomas.

Adenocarcinoma↗
PubMed1980

Ultrastructure of pancreatic tumors induced in Syrian hamsters by N-nitroso-2,6-dimethylmorpholine.

Tumors of the pancreas diagnosed as duct carcinomas and adenomas were induced in Syrian hamsters by intragastric administration of N-nitroso-2,6-dimethylmorpholine (2,6-DMNM). The ultrastructure of the well differentiated tumor cells reflected the morphology of normal duct epithelia while such features were less conspicuous in poorly differentiated neoplasms. Under the light and electron microscopes, the pancreatic tumors closely resembled those induced by N-nitroso-bis(2-hydroxypropyl)amine.

Adenoma↗
PubMed1980

Ganglioneuromas in the adrenal medulla of F344 rats.

Of 60,048 aging F344 rats, 28 had ganglioneuromas of the adrenal gland. The rats were between 58 and 122 weeks old; 25 of them between 93 and 122 weeks when the tumors were found. The neoplasms were composed of large or small typical ganglion cells with a large pale nucleus and a prominent, often eccentric, nucleolus. The ganglion cells usually were distributed throughout the medullary tumor and surrounded by various numbers of supporting cells, including Schwann's cell types, and capsular or satellite cells. Often there was no clear-cut border between ganglion cells and neoplastic pheochromocytes. Electron microscopy of re-embedded tissues showed neurosecretory granules and cytoplasmic areas with an extensive rough endoplasmic reticulum (Nissl substance) in the ganglion cells and axons. The Schwann's cells were surrounded by a basement membrane and formed long cytoplasmic extensions around the axons. Almost all ganglioneuromas were associated with neoplastic pheochromocytes which usually were located at the edge of the tumors.

Adrenal Gland Neoplasms↗
PubMed1980

Morphological and histochemical characteristics of pigments in aging F344 rats.

Pigments found in spleen, lymph nodes, kidney, thyroid, adrenal, liver, ovary, central nervous system, heart and connective tissues of aging F344 rats were studied morphologically and histochemically. The morphology of the pigment accumulations depended on the tissue affected. Pigments resembling lipofuscin were found in most of these tissues. The ultrastructural appearance of siderosomes in splenic macrophages suggested that erythrocyte degradation was responsible for pigment production. Adrenal ultrastructure showed that lipofuscin-like material may have originated from degradation of lipid droplets of epithelial cells.

Adrenal Glands↗
PubMed1980

Pathology of the clitoral and prepucial glands in aging F344 rats.

Clitoral and prepucial glands from 112-week-old untreated F344 male and female rats were studied histologically. Lesions included acinar cell atrophy, fibrosis, duct distension, inflammation, and neoplasms. Acinar cell atrophy and fibrosis were seen in 68% of the males and 58% of the females. More severe acinar cell atrophy, fibrosis, and inflammation were seen in the male rats. The neoplasms were small and circumscribed, cystic, or papillary cystic adenomas derived from acinar cells. One cystic adenocarcinoma was diagnosed.

Aging↗
PubMed1979

Carcinogenic effects of diethylstilbestrol in male Syrian golden hamsters and European hamsters.

The tumorigenic effects of sc-implanted diethylstilbestrol (DES) on male Syrian golden hamsters and European hamsters were compared. The adenohypophyses, kidneys, and testes of both species showed neoplastic responses to DES treatment. European hamsters were more sensitive than were Syrian hamsters, inasmuch as the European hamsters had a higher tumor incidence. The testicular tumors were all Leydig cell adenomas and seemed to depend on the coincident occurrence of hypophyseal neoplasms (all composed of gonadotropic cells). Of the European hamsters tested, 29% also developed liver tumors (hepatocellular adenomas, carcinomas, and cholangiocarcinomas.

Animals↗
PubMed1979

Bronchoscopy in the European hamster (Cricetus cricetus).

A pediatric bronchoscope was modified for use in the European hamster (Cricetus cricetus) and has been used successfully to obtain biopsy specimens from these animals. Biopsy specimens were obtained by means of small forceps with visual control given by the modified bronchoscope.

Animals↗
PubMed1979

Tissue differentiation as a prerequisite for transplacental carcinogenesis in the hamster respiratory system, with specific respect to the trachea.

The significance of tissue differentiation for the transplacental carcinogenicity of DEN was examined. In one experiment, pregnant Syrian golden hamsters received a single sc injection of DEN on one of the different days of pregnancy. Approximately 95% of the offspring of those mothers treated on one of the last 4 days (days 12--15) of gestation developed respiratory tract tumors. Transplacental DEN treatment before the 12th prenatal day failed to induce any neoplastic response in the young. In the second experiment, the differentiation of the prenatal Syrian golden hamster tracheal epithelium was examined histologically and by electron microscopy. We found that on the 12th prenatal day the ER occurred for the first time in its functionally competent form. On earlier prenatal days, the epithelial cells lacked this organelle. We conclude that this development of ER is a prerequisite for transplacental DEN carcinogenesis, since this organelle contains the nonspecific enzyme systems necessary for the transformation of DEN to its ultimate carcinogen.

Animals↗
PubMed1979

In vivo autoradiography and nitrosoheptamethyleneimine carcinogenesis in hamsters.

Quantitative autoradiograms were made, in vivo, in European hamsters with the use of [14C]nitrosoheptamethyleneimine (260 muCi/animal; time between administration of nitrosamine and killing of animals, 6 hr). In this species, the lung is the principal target, and radioactivity was found in the Clara cells of the bronchial epithelium and in the nitrosoheptamethyleneimine-induced tumors which derive from these cells. Tumors are not induced in the liver, which can metabolize this compound, and labeling is found principally in the cytoplasm, whereas in the target cells there is a high degree of labeling in both the cytoplasm and the nuclei.

Animals↗
PubMed1978

Ultrastructure of N-diethylnitrosamine induced tumours in the nasal olfactory region of the Syrian golden hamster.

Tumours of the nasal olfactory region induced in five Syrian golden hamsters ater s.c. treatment with N-diethylnitrosamine (DEN) were examined electron microscopically. The neoplasms consisted of two cell types, the ultrastructure of which showed them to have originated from the precursors of olfactory sensory cells (neuroblasts) and the precursors of sustentacular cells (basal cells).

Animals↗
PubMed1978

Ultrastructure of nitrosoheptamethyleneimine-induced lung tumors in European hamsters.

The ultrastructure of lung tumors induced in European hamsters through chronic subcutaneous treatment with nitrosoheptamethyleneimine (NHMI) is described. The neoplasms demonstrated either adenomatous (adenomas and adenocarcinomas) or mixed (tumors with areas of adenoid and squamous differentiation) pattern. Adenomatous areas consisted of Clara cells and of cells with lamellated inclusion bodies in their cytoplasm. Cells in areas with squamous differentiation contained cytoplasmic filaments and filament bundles as well as dense-cored granules.

Adenocarcinoma↗
PubMed1977

Pulmonary tumorigenesis in Syrian golden hamsters after intratracheal instillations with automobile exhaust condensate.

Syrian golden hamsters were intratracheally instilled once every two weeks for life with automobile exhaust condensate (AEC) at two dose levels. The condensate was prepared from the most common German passenger car driven in the Europa-Test cycle (simulated city driving) and contained 340 microgram/g benzo(a)pyrene (B(a)P). Despite the very low total dose of B(a)P received, all animals of both dosage groups developed multiple pulmonary adenomas. Electron microscopy revealed these tumors to resemble B(a)P induced pulmonary adenomas in their ultrastructure. Numerous condensate-laden macrophages in tumor and peripheral lung tissues indicated that little of the instilled condensate had been removed from the airways through mucociliary action.

Adenoma↗
PubMed1977

Ultrastructural alterations of APUD cells during nitrosamine-induced lung carcinogenesis.

Groups of Syrian golden hamsters were treated twice weekly for life with 1/10 LD50 DEN, or once weekly for life with 1/5 LD50 DBN. The sequential alterations in the ultrastructure of Apud cells in their bronchial lining were examined. Both carcinogens caused pronounced proliferation of this cell type during the initial treatment period. Thereafter, the formation of increasing numbers of filamentous bundles was observed in the cytoplasm of the Apud cells, whereas their neurosecretory granules decreased in number. The present findings suggest that after an initial phase of proliferation, the Apud cells undergo squamous metaplasia when treated with the two nitrosamines investigated.

Animals↗
PubMed1977

Ultrastructure of N-dibutylnitrosamine-induced tumors of the urinary bladder in European hamsters.

European hamsters were treated sc with 0.025 the median lethan dose of N-dibutylnitrosamine. The induced neoplasms of the urinary bladder (transitional cell carcinomas and squamous cell carcinomas) were examined electron microscopically. Their ultrastructure indicated these tumors to be different developmental stages of the same type of tumor rather than two fundamentally different types of neoplasm.

Animals↗