Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Nitroso Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed1975

[Effect of N-nitroso compounds and aminoazo compound on organ cultures of human embryonal kidney].

It was shown that embryonal tissue of human kidney could be explanted into organ cultures during 3-4 weeks. In the immediate effect of N-methyl nitrosurea (NMU), dimethyl nitrosamine (DMNA) and orthoamino-azotoluole (OAAT) a considerable number of hyperplastic epithelial growths was revealed, various types of morphological changes: tubular epithelium hyperplasia, glomerular epithelium hyperplasia and mixed hyperplasia (simultaneous hyperplasia in tubular and glomerular epithelium) being noted. Their frequency increased as the experiment proceeded, and also was dependent on the carcinogen concentration in a nutrient medium. NMU mostly produced a hyperplastic growth in tubular epithelium, DMNA--in glomerular epithelium while OAAT resulted in enhancement of hyperplastic processes in tubular and glomerular epithelium.

Azo Compounds↗
PubMed1991

Retinoids prevent epithelial carcinogenesis induced by N-nitroso compounds.

Two new retinoic acid esters and retinamides synthesized in China, N-(4-ethoxycarbophenyl)retinamide (RI) and N-(4-carboxyphenyl)retinamide (RII), significantly inhibited carcinogenesis induced in the epithelium of the forestomach of mice by N-nitrososarcosine ethyl ester. RI also markedly inhibited carcinogenesis induced in the epithelium of the oesophagus and forestomach in rats by this ester. No sign of hypervitaminosis was noticed with doses as high as six times the therapeutic dose. RI also inhibited precancerous and cancerous lesions in the nasal cavity and nasopharynx and oesophagus of rats induced by dinitrosopiperazine. In a malignant oesophageal epithelial cell line from rats, RE25-3, established in our laboratory, RI and RII inhibited mitosis, proliferation rate, chromosomal aberrations and incorporation of 3H-thymidine into DNA. The ability to form colonies on agar plates was also inhibited by these two compounds.

Animals↗
PubMed1978

Mechanisms of inhibition by ascorbate of microbial mutagenesis induced by N-nitroso compounds.

Mutagenesis induced by N-methyl-N-nitrosoguanidine (MNNG) and dimethylnitrosamine (DMN) in Salmonella TA 1530 was inhibited by ascorbate. Inhibition of MNNG-induced mutagenesis resulted from a reaction between ascorbate and MNNG that led to consumption of MNNG. The rate of this reaction was considerably enhanced by catalytic amounts of Cu(II) and Fe(III). No direct reaction between DMN and ascorbate was detectable, but relatively high concentrations of Cu(II) enchanced inhibition of DMN-induced mutagenesis by ascorbate. Added protein reduced the effectiveness of Cu(II) as a catalyst of the reaction between ascorbate and MNNG, which suggested that the microsomal protein necessary to activate DMN, may reduce the concentration of free Cu(II) and thereby lower its catalytic efficiency. Mutagenesis by N-methyl-N-nitrosourea was not inhibited by ascorbate.

Animals↗
PubMed1984

Genetic activity in yeast assays of reputed nonmutagenic, carcinogenic N-nitroso compounds and methapyrilene hydrochloride.

Methapyrilene hydrochloride (MPHC), N-nitrosomethylaniline (NMA), N-nitrosomethyl-3-carboxypropylamine (NMCP) and N-nitrosodiethanolamine (NDELA) are reputed to be nonmutagenic carcinogens because they are genetically inactive in Salmonella mutagenesis tests but produce cancer in rats. We have assayed these compounds for their genetic activity with diploid strains D7, D7-144, and RMO52 of Saccharomyces cerevisiae. The compounds MPHC and NMA were highly toxic to the cells and induced gene conversion and reverse mutations in strains D7, D7-144 and RMO52. Metabolic activation was not required for this activity. However, in acidic (pH 5) medium, the genetic activity and cell toxicity of MPHC and NMA were markedly reduced. Ascorbic acid suppressed the mutagenicity and toxic effects of MPHC. Mutagenicity of NDELA was enhanced in strain D7-144 when cells were treated in acidic medium. At pH 7, NDELA was not mutagenic. NMCP induced reversed mutations in strains D7-144 and RMO52 in the absence of metabolic activation. Our results indicate that the four carcinogens, MPHC, NMA, NMCP and NDELA, require different physiological conditions for the expression of their genetic activity.

Aminopyridines↗
PubMed1980

[On the problems in respect ot the formation of N-nitroso compound precursors when using alkylating agents in the fumigation of foodstuffs. I. Investigations of the formation of secondary amines by the action of ethylene oxide on primary amines and amino acids (author's transl)].

Special attention must be paid to the formation of secondary amines as precursors of nitrosamines as a possible consequence of the fumigation of foodstuffs with ethylene oxide. Investigations carried out in vitro show that secondary amines can result in various ways by reaction of the amine groups with ethylene oxide: 1. directly, by reaction of ethylene oxide with primary amines, 2. by reaction with amino acids followed by decarboxylation. Identification of the secondary amines produced by the reaction of ethylene oxide with primary amines or amino acids was carried out by means of thin layer chromatography. In this manner, the formation of methylamino ethanol, ethylamino ethanol and diethanolamine was demonstrated by the reaction of ethylene oxide with methylamine, ethylamine and ethanolamine. Furthermore, the reaction of ethylene oxide with glycine and serine followed by decarboxylation produced, depending upon the pH value, the compounds methylamino ethanol and diethanolamine.

Amines↗