Репозиторий Университета

© 2018, Institute of Chemistry, Slovak Academy of Sciences. This work focuses on the behavior and comparative assessment of the antioxidant activity of several well-known antioxidants using three different approaches with the same ABTS•+/potassium persulfate radical-generating system: a decolorization assay, kinetic assay, and visual-spectrophotometric titration assay. The decolorization assay is the most common approach but gives little information on antioxidant behavior. The kinetic assay can be used for an in-depth study of the specific features of a particular antioxidant and facilitates identification of the mechanism of action. The visual-spectrophotometric titration assay is complementary to the above assays and subdivided into two stages to demonstrate the contribution of the “fast” and “slow” scavenging properties to the total antioxidant activity. The trolox equivalent antioxidant capacity (TEAC) value ranges for several flavonoids and the endogenous antioxidants derived from these assays vary from 0.7 to 5.1, 0.5–2.8, and 0.4–3.7, respectively, while the sequence of the weakest antioxidant to the strongest is similar. The analysis of the kinetic curves for some flavonoids showed that their interaction with ABTS•+ has an atypical character. Based on the results of the kinetic and visual-spectrophotometric titration assays, fast-reacting (trolox, α-tocopherol), slow-reacting (naringenin, apigenin) and moderate-reacting antioxidant (dihydroquercetin, quercetin, rutin, morin, and glutathione) compounds were distinguished.

© 2018, Pediatria Ltd. All rights reserved. The article presents results of the study of glutathione-S-transferase GSTM1 and GSTT1 genes polymorphism in children with an isolated form of esophageal atresia (EA) with tracheoesophageal fistula and without fistula. Study materials and methods: 130 children were examined, including 39 children with EA and 91 children without EA, whose mothers did not consume tobacco or alcohol during pregnancy. All children belong to the Russian ethnic group. Samples of DNA for further analysis were obtained from buccal epithelial cells. Typing of allelic polymorphism of GSTM1 and GSTT1 genes was performed by Real-time PCR and quantitative PCR. Results: in children with an isolated EA the study revealed a statistically significant increase in the frequency of heterozygous genotypes (+/del) for GSTM1 in comparison with the frequency estimate in the control group (χ2=6,74 df=1, p<0,001). Conclusion: the association of EA with the heterozygous genotype of GSTM1 gene was first established, which may indicate a higher risk of pathology development for carriers of this genotype. The authors believe that EA formation depends on the cumulative effect of mother and newborn genotypes, leading to a decrease in GSTM1 enzyme catalytic activity. To determine the hereditary predisposition to EA development in a fetus it is reasonable to determine the glutathione-S-transferase genes polymorphisms in pregnant women who smoke and consume alcohol, as well as pregnant women living in ecologically unfavorable regions.

© 2018 Izdatel'stvo Meditsina. All rights reserved. Okadaic acid (OA) is relating to the number of seafood toxins causing diarrhea. At the present time, there was determined the toxicity index of OA; the main target molecules of its action, its role as a promoter of tumor processes and apoptosis have been investigated. However, in the available literature, data on the toxicokinetics of OA and molecular biomarkers of its action for warm-blooded animals are practically absent. The purpose of this work was to determine biomarkers of toxicity of OA in experiments in vivo and ex vivo. The experiment was performed on 74 male Wistar rats with an initial body weight of 100 ± 10 g. In the work, there was used a solution of OA in methanol, produced by “FermentecLtd.” (Israel). Prior to the studies, methanol was removed from the preparation. To obtain working dilutions of the toxin, aliquots of the alcoholic OA solution with a concentration of 10 ppm were diluted with a sterile solution of 0.15M NaCl to obtain solutions with a concentration of OA of 50, 100 and 150 ppb. These solutions were administered to the rats in doses of 1 ml/kg of body weight intraperitoneally. The animals of the control groups were injected with NaCl solution. Excretion of animals from the experiment was carried out 6, 24 and 168 hours after the administration of OA preparations by decapitation under ether anesthesia. The mass of internal organs, biochemical and hematological blood indices, the activity of glutathione peroxidase, non-protein thiols in the liver, cytokine levels of IFN-, IL-10, IL-17A in blood plasma and liver cell lysates, liver cell apoptosis, malonic dialdehyde level in the liver were analyzed. Studies have shown minimal manifestations of toxic effects of OA in case of intraperitoneal administration (shifts in the ratio of neutrophils and lymphocytes, increased activity of AST, changes in the activity of glutathione peroxidase) to be observed even at a dose of 50 μg/kg of body weight. Taking into account the safety factor of 3, the ARfD level of OA should be revised and accepted to be equal to 0.27 μg/kg of body weight. The data obtained indicate the need for additional risk assessments of this toxin for the health of consumers and, possibly, a revision of the established values of the safe content of this toxin in mollusks. For the first time, there was shown the possibility of using the following marker of toxic action of OA: non-protein thiols, the activity of glutathione peroxidase, and the content of malonic dialdehyde in the liver.