صفحه 1 از جانب 16 نتایج
In rats, N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) induce liver tumours and, to a lesser extent, nasal tumours. Polybrominated biphenyls (PBBs) are liver tumour promoters and are highly persistent in tissues of rats. To characterize the development of preneoplastic lesions in the
The toxicological evaluation and histopathological findings of a long-term inhalation study in progress with N-nitrosodimethylamine (NDMA) are presented. Exposure was to three concentrations of NDMA: 0.04, 0.2 and 1.0 ppm (corresponding to 120, 600 and 3000 micrograms/m3). A significant reduction in
Previous studies have demonstrated that rats fed Chinese salted fish developed carcinomas of the nasopharynx and nasal cavity. In the present work the contents of nitrosamines in salted fish from the city of Guangzhou, southern China, and the contents of nitrosamines and possible nitrosamine-induced
Female Sprague-Dawley rats were given an ip dose of N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR), singly or in combination, and the sequential development of lesions in the liver and nasal cavity was characterized. Liver and nasal tissues were collected from rats given either NDMA
Four nitrosomethylalkylamines were given to F344 rats in drinking water at concentrations of 0.22 mM or less. The total doses delivered to each animal were 0.5 and 0.2 mmol of nitrosodimethylamine (NDMA), 0.6 mmol of nitrosomethyl-2-oxopropylamine (NMOP) and nitrosomethyl-2-hydroxy-propylamine
The tumorigenic activities and DNA methylating abilities in F344 rats of the tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and the structurally related nitrosamine N-nitrosodimethylamine (NDMA) were compared. Groups of 30 male rats were given 60 s.c. injections of
The endogenous formation of metabolites of NO - nitrite (NI), nitrates (NA) and volatile nitrosamines in the body, tumor tissue and by abdominal cavity by macrophages for dynamics was investigated in mice F1(C57BlxCBA), Balb/c and BDF with subcutaneous transplanted tumors (Erlich carcinoma - EC and
UNASSIGNED
The possible alternative approach to whole-organ transplantation is a cell-based therapy, which can also be used as a "bridge" to liver transplantation. However, morphological and functional changes in the liver of patients suffering from chronic liver fibrosis and cirrhosis restrict the
An ex vivo model to detect nonspecific DNA damage in different rat tissues has been developed and employed to study systemic properties of tobacco-specific N-nitrosamines. One hour after treatment of rats with the carcinogens, primary, intact cells were isolated from various organs. Viability of the
The carcinogenic effectiveness of 5 simple aliphatic nitrosamines was compared by feeding to groups of 20 Fischer rats in drinking water. Nitrosodi-isobutylamine was by far the weakest carcinogen, giving rise after comparatively high doses to tumors of the nasal cavity and trachea.
Disulfiram (DSF) can considerably alter the organotropy of chemical carcinogens. For N-nitrosodimethylamine and for N-nitrosodiethylamine the organotropy is shifted from the liver to the nasal cavity or the oesophagus, respectively. Whereas the influence of DSF or its metabolites on enzyme systems
Parathymic lymph nodes as potential sites of tumor progression have been neglected in humans. We have established a rat renal capsule-parathymic lymph node model to study in vivo metastasis. Epithelial liver carcinoma (HeDe) and mesenchymal mesoblastic nephroma (NeDe) cell lines have been
OBJECTIVE
This study evaluates whether wood dust and/or wood preservatives develop a carcinogenic potential against the tissues of the airways of rats.
METHODS
The formation of tumors of the respiratory tract after exposure to wood dust was studied in six groups of approximately 60 female Fischer
Azoxyalkanes are isomeric with nitrosodialkylamines and could be similar in their biochemical and biological actions. To compare the structure-activity relations in the two series, the tumorigenic activities of four azoxyalkanes, azoxymethane, azoxyethane, Z-ethyl-O,N,N-azoxymethane, and
Kinetic parameters were determined for the hydroxylation of N'-nitrosonornicotine (NNN), N-nitrosobenzylmethylamine (NBzMA), coumarin, and ethoxycoumarin catalyzed by rat nasal mucosa microsomes. NNN is a tobacco-specific nitrosamine that, in rats, causes tumors in the nasal cavity and esophagus,