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Biomedical subjects

P P Dikun

Publications and source records attributed to P P Dikun.

At least 19 recordsLinked to original sources
PubMed1998

Assessment of benz(a)pyrene pollution in the flood area of the Luga river.

Benz(a)pyrene pollution levels have been identified in the soils and vegetation of the flood plains of the River Luga, Leningrad Region. Maximum pollution exceeding background levels 2-10 times (11.02-52.71 mkg/kg) was detected in the soils around the towns of Luga and Kingisepp. The benz(a)pyrene levels in the vegetation (2.04 mkg/kg) were below background values. No significant correlation was established between the concentrations of pollution in the soil and vegetation. Our data suggest that the area of the mid-course of the River Luga should be preserved as a natural habitat of the plants of the Poaceae family.

Benzo(a)pyrene↗
PubMed1994

Individual values of excretion of benzo[a]pyrene metabolites and susceptibility to its carcinogenic effect in rats.

In white outbred LIO rats exposed to multiple intraperitoneal (i.p.) doses (10 mg/kg) of benzo[a]pyrene (BP) in the form of a water-lipid emulsion, individual peculiarities of the excretion of its metabolites, BP-7,8-diol and 3-hydroxy-BP (3-OH-BP) in urine and feces were detected and compared with the carcinogenic effect. Parameters of BP metabolite excretion differed from those found in our previous experiments with rats exposed to single high i.p. doses of BP (100 and 200 mg/kg), dissolved in sunflower oil [11,12]. In comparison with our previous observation, in the present study, the carcinogenic effect was considerably weaker (5/22 versus 10/19). The rats that developed tumours of internal tissues (four peritoneal malignant histiocytomas and one lung lymphosarcoma), excreted higher quantities of BP-7,8-diol in the urine than other rats. The possible implication of monitoring excretion of BP metabolites for predicting individual susceptibility to its carcinogenic effect is discussed.

Animals↗
PubMed1994

[Benz(a)pyrenes and N-nitrosamines in dry dairy products].

Results of works induding study of effect of different factors (environment, type of equipment, technology) on content of cancerogenic substances in dry milk products were summarized. Possible reasons of appearance of cancerogens in milk in process of drying were determined, dataes of concentration of benz(a)pyren and N-nytrozamens in milk and warmth carrier before and after drying were established. Explanation of separate appearances which connect with change of quantity of cancerogens in product on different stages of drying was suggested.

Animals↗
PubMed1993

[Evaluation of a drying procedure for dairy products coming in direct contact with flue gases from the oncologic viewpoint].

The study was concerned with ambient air and heat-transfer medium levels of benzo(a)-pyrene (BP) and N-nitrosoamines (NA) measured at the input and output of the drying chamber of two milk dryers using different systems of heat generation. Said concentrations were ascertained in the dried product (casein), too. One installation used electricity-heated ambient air, while the other--air-diluted products of natural gas combustion. No significant difference was registered for both dryers between ambient-air and heat-transfer medium concentrations of BP and two NAs detected--NDMA and NDEA. There was no significant difference between BP levels in the casein produced on those installations, the raw material coming from the same lot. The study registered reverse changes in NDMA and NDEA concentrations, with ambient air being heated in the heat generator and heat-transfer agent cooled in the drying chamber.

Animals↗
PubMed1992

Biomarkers for individual susceptibility to carcinogenic agents: excretion and carcinogenic risk of benzo[a]pyrene metabolites.

In rats exposed to a single intraperitoneal dose of 200 mg/kg of the environmental carcinogen benzo[a]pyrene (BP) in sunflower oil, significant individual variations in excretion of the BP activation (BP-7,8-diol) and deactivation (3-OH-BP) derivatives were found. Most rats developed peritoneal sarcomas. Only the levels of BP-7,8-diol excreted in the urine correlated directly with the latency of tumor formation. After a similar exposure to a dose of 100 mg/kg BP, Macaca fascicularis monkeys excreted smaller quantities than rats of both metabolites. After rats were given 10 intraperitoneal injections each of 10 mg/kg of BP in a water-lipid emulsion, the excreted levels of both metabolites after the first, fifth, and tenth injection were lower than those of the rats that received 200 mg/kg. BP metabolites were also detected in the urine of lung cancer patients who were heavy smokers. The applicability of monitoring the excretion of the BP metabolites to predicting individual cancer risk is discussed.

Animals↗
PubMed1992

[A comparative study of the individual characteristics of the excretion of metabolites of benzo(a)pyrene and its carcinogenic effect in rats].

Nineteen outbred LIO rats received a single intraperitoneal injection of 200 mg/kg benzo(a)pyrene (BP) in sunflower oil. Levels of excretion of a BP activation product 7.8-BP-dihydrodiol and deactivation product 3-hydroxy-BP showed significant individual variations. Half the animals developed intraperitoneal sarcoma at various stages of the experiment. A direct correlation between urine 7.8-BP-dihydrodiol excretion level and tumor latency was established. The value of metabolite excretion level monitoring for making individual prognosis of BP carcinogenic effect is discussed.

Animals↗
PubMed1991

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.

Antioxidants↗
PubMed1990

[The individual characteristics of the excretion of benzo(a)pyrene metabolites in rats].

Assessment of individual peculiarities of carcinogen metabolism in the body opens up new vistas in predicting individual sensitivity to these agents. The authors developed a spectrofluorometric [correction of spectrofluorescence] technique to assay concentrations of carcinogenic benzo(a)-pyrene (BP) metabolite (7,8-BP) and a product of its detoxication (3-BP) in excreta of male rats who had been given a single dose of 200 mg/kg of benzo(a)pyrene intraperitoneally. Ten-thirty times daily variations in individual levels of both metabolites were accompanied by less variation in their total amount. Parameters of BP metabolism perhaps can be used for predicting individual risk of BP-induced tumor development.

Animals↗
PubMed1990

[Pulsed method of sampling in monitoring of carcinogenic substances in gaseous atmosphere].

Experiments using various types of gas samplers showed that application of A phi A type fibrous material-containing filters for benzo(a)pyrene monitoring may result in significant underestimation of the carcinogen level in the air. The authors developed pulsed sampler using suspended layer of sorbent which proved most effective in catching benzo(a)pyrene in gaseous atmosphere. The unit allows simultaneous sampling of carcinogenic polycyclic aromatic hydrocarbons and N-nitroso compounds.

Air Pollutants↗
PubMed1989

[Effect of lignins and their model compounds on amine nitrosation in a human gastric juice medium and in the body of mice].

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.

Animals↗
PubMed1989

[The action of inhibitors of the amine nitrosation reaction in human gastric juice and in the body of animals].

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.

Aminopyrine↗
PubMed1987

[Determination of N-nitroso compounds in the gastric juice for evaluation of the individual nitrosating capacity of the body].

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.

Aminopyrine↗