পৃষ্ঠা 1 থেকে 69 ফলাফল
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the tobacco-specific N-nitrosamine, labeled with 14C on the carbonyl group, was given iv or orally to F334 rats. The animals were killed 4 hours later, and the localization of bound radioactivity in the nasal cavities was studied by light
The tissue localization of the DNA adducts O6- and 7-methylguanine induced in the nasal cavity by the nicotine-derived carcinogen 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK, 30 mg/kg intraperitoneally) has been investigated immunocytochemically in male Sprague-Dawley rats.
Experimental identification of potential chemopreventive or tumor promotive agents in the lung is important. Establishment of short-term bioassay models is therefore a high priority. In an attempt to induce strong promotion effects, in Experiment 1, left thoracotomy was performed on A/J mice at week
The Areca-derived 3-(methylnitrosamino)propionitrile (MNPN) was tested for its tumor initiating activity on mouse skin and for its tumorigenic potential in the oral mucosa of rats. On mouse skin, like the otherwise strongly carcinogenic, tobacco-specific
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its analogues substituted with deuterium at the methylene carbon, 4,4-dideutero-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone [4,4-D2)NNK], and the methyl carbon, 4-(trideuteromethylnitrosamino)-1-(3-pyridyl)-1-butanone [(CD3)NNK], adjacent
The metabolism of the tobacco-specific carcinogen, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), was studied in the F344 rat, in which it induces tumors of the nasal cavity, liver, and lung. When NNK was incubated with rat liver microsomes and a reduced nicotinamide adenine dinucleotide
Smokeless tobacco products have been associated with increased risks of oro-pharyngeal cancers, due in part to the presence of tobacco-specific nitrosamines (TSNAs) such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These potent carcinogens are formed during tobacco curing and as a result
In an earlier study, young male and female mink (Mustela vison) were found to be highly susceptible to the carcinogenic effect of N'-nitrosonornicotine (NNN). In this follow-up study we tested (i) the importance of the age of the animals with regard to the carcinogenic effect of NNN, (ii) the
The tissue distribution of the tobacco-specific N-nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in the F344 rat was studied by whole-body autoradiography and high-performance liquid chromatography. The results of the wholebody autoradiography experiments indicate that the
In this study we assayed the effects of snuff and nicotine on the DNA methylation by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a powerful tobacco-specific N-nitrosamine. Male F344 rats were pretreated for 2 weeks with either a solution of a snuff extract or 0.002% nicotine in the
The tobacco-specific carcinogens, N'-nitrosonornicotine (NNN) and 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), were tested for carcinogenicity in F344 rats. Each nitrosamine in trioctanoin was administered by s.c. injection to 12 male and 12 female rats over a period of 20 weeks. The
4-(N-Methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a major nitrosamine formed in tobacco smoke, induces a high incidence of lung, liver, and nasal cavity tumors in rats. Since alpha-hydroxylation of NNK by target tissues can lead to the generation of a methylating agent, the formation and
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent carcinogen in adult laboratory rodents. Our previous studies have shown that NNK crosses the placenta in pregnant hamsters and is metabolized into DNA-methylating and clastogenic intermediates by fetal
The rat lung and nasal cavity are two target organs for carcinogenesis by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In order to characterize further the enzymes involved in the bioactivation of NNK, detailed kinetic and inhibitory studies were conducted with rat lung and nasal mucosa
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