[The dependence of the nitrosation activity of the gastric juice in humans on their age and the type of pathological status of the gastric mucosa]. / Zavisimost' nitroziruiushchei aktivnosti zheludochnogo soka liudei ot vozrasta i tipa patologicheskogo sostoianiia slizistoi obolochki zheludka.

The study involved two groups of patients aged 6-14 and 40-60 years, and identification of different conditions of gastric mucosa. The study has established a correlation between the nitrosation activity and acidity of gastric juice and the pathological condition of the gastric mucosa. Enhanced nitrosation activity was observed in samples with a pH under 4.0. That activity was at its lowest in cases of normal gastric mucosa, and at its peak--in high-acidity superficial and erosive gastritis. In cases of superficial gastritis with similar levels of acidity, the nitrosation activity of gastric juice for different amines in children was 2-4 times that in adults. The difference in nitrosation levels for different amines tended to diminish with the decrease in the basicity of the amine in question. A linear correlation was observed between the free-radical activity of gastric juice samples and nitrosation activity (correlation coefficient, k = 0.72).

Some approaches to prevention of endogenous formation of N-nitrosamines in humans.

In a series of experiments on formation of N-nitrosamines from precursors in the gastric juice, we investigated individual nitrosation capacity and the influence of inhibitors on this process. In the presence of a molar ratio of 2:1 ascorbic acid:NaNO2, we found increased nitrosamine formation in 34% of gastric juice samples. Ferulic acid and caffeic acid generally suppressed nitrosation at high concentrations and stimulated it at low concentrations. The concentration at which the transition from a stimulating to an inhibitory effect occurs depends on individual differences in the gastric juice.

[The formation of carcinogenic nitrosamines from a small amount of precursors in human gastric juice]. / Obrazovanie kantserogennykh nitrozaminov iz malogo kolichestva predshestvennikov v zheludochnom soke cheloveka.

It has been shown in vitro with human acidic gastric juice the nitrosomorpholine (NMOR) formation from small doses of precursors (sodium nitrite and morpholine) with a significant difference relative to the control. The presented data suggest the possibility of the nitrosation reaction in the human gastric juice under hypo- and anacidic conditions. The data obtained are one more experimental confirmation of the epidemiological evidence of the potential role of nitrates (nitrites) in the etiology of stomach and esophageal cancers.

[Effect of human gastric juice on dimethylamine nitrosation by sodium nitrite]. / Vliianie zheludochnogo soka na nitrozirovanie dimetilamina nitritom natriia.

The study was concerned with evaluation of the effect of human gastric juice (samples obtained from 157 subjects) on in vitro dimethylnitrosamine nitrosation by sodium nitrite versus gastric mucosa pathology (gastritis, polyps, ulcer, cancer), gastric juice pH and nitrate ion level. Also, the influence of gastric juice glycosaminoglycans and glycoproteins levels as well as N-acetylneuraminic acid isolated from porcine blood was assessed. An increased nitrosating activity of gastric juice was observed in cases of gastritis and ulcer and in those with low nitrate ion activity. Glycosaminoglycans and glycoproteins were found to inhibit nitrosation. N-acetylneuraminic acid in the concentrations used exerted no effect on dimethylnitrosamine nitrosation by sodium nitrite.

[Assessment of the degree of carcinogenicity of small doses of nitrites]. / Otsenka stepeni kantserogennoi opasnosti malykh doz nitritov.

Chronic experiments on CBA and C57B1 mice and acute experiments on CBA mice established: (a) carcinogenic effect of sodium nitrite given continuously with drinking water (0.1; 1.0 and 10.0 maximum allowable concentration) in combination with morpholine fed with bread, and (b) endogenous synthesis of nitrosomorpholine as a result of simultaneous intragastric administration of same doses of sodium nitrite and morpholine. Also, nitrosomorpholine and N-nitrosodimethylamine synthesis was observed in vitro following addition of low-dose sodium nitrite, morpholine and amidopyrine to human gastric juice. Carcinogenic hazard associated with low-dose nitrite consumption in humans is discussed.

[Effect of lignins and their model compounds on amine nitrosation in a human gastric juice medium and in the body of mice]. / Vliianie ligninov i nekotorykh ikh model'nykh soedinenii na nitrozirovanie aminov v srede zheludochnogo soka cheloveka i v organizme myshei.

The study was concerned with the influence of lignins of leaf-bearing and coniferous timber and 22 model compounds (lignin components) on nitrosation of dimethylamine, amidopyrine and morpholine in human gastric juice. Some results of the study were confirmed in murine experiments. Compounds of the guaiacyl series showed the highest inhibitory activity. Lignins of coniferous timber proved most effective.

[The action of inhibitors of the amine nitrosation reaction in human gastric juice and in the body of animals]. / Deistvie ingibitorov reaktsii nirtrozirovaniia aminov v zheludochnom soke cheloveka i v organizme zhivotnykh.

The effect of ascorbic, ferulic and caffeic acids on dimethylamine and amidopyrine nitrosation in a medium containing 3 samples of total gastric juice taken from 10 humans (pH = 6.1; 3.2 and 1.7) was studied versus the amount of inhibitor added to the medium. The resultant relationship proved bizarre, the inhibitor at low concentrations stimulating nitrosation in some situations. When gastric juice concentration in the medium was further lowered by dilution with a buffer at relevant value of pH, the paradoxical effect of inhibition gradually disappeared.

[Determination of N-nitroso compounds in the gastric juice for evaluation of the individual nitrosating capacity of the body]. / Opredelenie N-nitrozosoedinenii v zheludochnom soke dlia otsenki individual'noi nitroziruiushchei sposobnosti organizma.

The article deals with a comparison of the results of human body nitrosating ability determination by two methods: (a) nitroso compound (NC) assay in diurnal urine after oral administration of its precursors, and (b) assay of the same in gastric juice after in vitro addition of precursors. The data for the first part of the investigation were obtained from the literature, and for the second one--from the experiments by the authors. Both studies used essentially identical groups of patients, primarily those suffering gastrointestinal pathology. Since the results matched to a considerable degree, it was inferred that (1) gastric juice is a factor of body nitrosating ability, and (2) in vitro determinations of said ability in gastric juice are fully justified. Moreover, the latter procedure is sometimes more practicable, particularly, in view of the marked relationship between nitrosating ability, and, especially, the efficacy of inhibitors of NC endogenous synthesis, on the one hand, and the individual characteristics of the body, on the other.

[Abnormal effect of nitrosation inhibitors in human gastric juice]. / Anomal'nyi éffekt ingibitorov nitrozirovaniia pri deistvii ikh v srede zheludochnogo soka liudei.

The paper discusses the effect of vitamins C and E and Plantaglucide on nitroso compounds yield in the course of nitrosation of amines in human gastric juice. The study group included 56 subjects. The above drugs capable of inhibiting in vitro nitrosation produced an anomalous effect in gastric juice of some subjects, i.e. potentiated nitroso compounds yield in nitrosation of amines by sodium nitrite. The said action of vitamins C and E was apparent in dimethylamine and amidopyrine nitrosation but it was not in morpholine nitrosation. Sharply increased levels in nitroso compounds were observed in some mice fed precursors of nitroso compounds in combination with vitamin C and Plantaglucide. These data point to an anomalous effect of the drugs on the body.

The influence of ethanol on synthesis of N-nitrosodimethylamine in vivo and in vitro.

The yield of N-nitrosodimethylamine (NDMA) has been studied in the nitrosation reaction in the presence or in the absence of ethanol. In the experiments in vivo the mice underwent intragastric administration of amidopyrin and sodium nitrite, and in the experiments in vitro dimethylamine (DMA) and sodium nitrite were used. It has been established that both in vivo (in the stomach of mice) and in vitro (in the medium of pure reagents and human gastric juice) ethanol inhibited the reaction of nitrosation by amines in acid media, thus decreasing the yield of NDMA.

[The effect of alcohol on DMNA synthesis from its precursors in vivo and in vitro]. / Vliianie alkogolia na sintez NDMA iz ego predshestvennikov v opytakh in vivo i in vitro.

The study was concerned with a comparison of the effects of ethanol on N-nitrosodimethylamine (NDMA) synthesis from amidopyrine and sodium nitrite in rat stomach and on the same synthesis from dimethylamine (DMA) and sodium nitrite involving a 30-min incubation of their mixture at 37 degrees C in acid medium. Alcohol was found to inhibit DMA nitrosation thus lowering the yield of NDMA both in rat stomach and in a medium containing human gastric juice or glycine-hydrochloride buffer (pH = 3.4).