The Effect of Selenium Supplementation in the Prevention of DNA Damage in White Blood Cells of Hemodialyzed Patients: A Pilot Study

Patients with chronic kidney disease (CKD) have an increased incidence of cancer. It is well known that long periods of hemodialysis (HD) treatment are linked to DNA damage due to oxidative stress. In this study, we examined the effect of selenium (Se) supplementation to CKD patients on HD on the prevention of oxidative DNA damage in white blood cells. Blood samples were drawn from 42 CKD patients on HD (at the beginning of the study and after 1 and 3 months) and from 30 healthy controls. Twenty-two patients were supplemented with 200 μg Se (as Se-rich yeast) per day and 20 with placebo (baker's yeast) for 3 months. Se concentration in plasma and DNA damage in white blood cells expressed as the tail moment, including single-strand breaks (SSB) and oxidative bases lesion in DNA, using formamidopyrimidine glycosylase (FPG), were measured. Se concentration in patients was significantly lower than in healthy subjects (P < 0.0001) and increased significantly after 3 months of Se supplementation (P < 0.0001). Tail moment (SSB) in patients before the study was three times higher than in healthy subjects (P < 0.01). After 3 months of Se supplementation, it decreased significantly (P < 0.01) and was about 16% lower than in healthy subjects. The oxidative bases lesion in DNA (tail moment, FPG) of HD patients at the beginning of the study was significantly higher (P < 0.01) compared with controls, and 3 months after Se supplementation it was 2.6 times lower than in controls (P < 0.01). No changes in tail moment was observed in the placebo group. In conclusion, our study shows that in CKD patients on HD, DNA damage in white blood cells is higher than in healthy controls, and Se supplementation prevents the damage of DNA

Research Into Kinetic Patterns of Chemical Metallization of Powder­like Polyvinylchloride

We present kinetic patterns of metallization of zinc-activated polyvinylchloride in the solution of chemical copper plating. The influence was studied of pH of the medium and the amount of metal of the activator on the copper deposition rate on the activated polymeric surface. It was established that in the case of activation of the polymeric surface with zinc, the solution undergoes two competing reactions of copper reduction. By using a volumetric method, we determined that pH of the medium exerts a decisive impact on the reduction mechanism of copper. It is proved that with the growth of pH in the solutions of chemical copper plating and the amount of metal-activator, the amount of copper reduced as a result of exchange reaction with zinc increases. The optimal pH of the solutions for the course of reaction of copper reduction by formaldehyde is 12. The obtained samples of metallized powder-like polyvinylchloride contain a significant quantity of copper on the surface and could be used to create metal-filled composites.The research conducted allows us to establish optimal conditions and effectively influence the copper reduction process on the activated polymeric surface in the solutions of chemical metallization. By changing the speed and efficiency of copper deposition on the polymeric surface, it is possible to control the content of metal in polymeric composites that are obtained from such materials, and thus control their propertie