[Polymorphisms in the oxidative stress-related genes and cancer risk]. / Polimorfizm genów obrony antyoksydacyjnej a ryzyko rozwoju raka.

Oxidative damage induced by the generation of reactive oxygen species (ROS) is thought to be related to human cancer aetiology. Oxidative stress can result in DNA damage, including oxidized bases, formation of DNA adducts and DNA strand breaks, as well as lipid peroxidation, protein modification, membrane disruption and mitochondrial damage. The effect of reactive oxygen species is balanced by the antioxidant action ofnonenzymatic antioxidants (e.g. vitamins A, C, E, glutathione and flavonoids), as well as antioxidant enzymes. There are three main types of antioxidant defence enzymes: superoxide dismutases, catalase and glutathione peroxidases. A variety of cancer cells are known to have lower antioxidant enzyme activity when compared with their normal counterparts. Many studies have examined genetic variation in the genes coding for these enzymes and their relationship to cancer risk. Only a few genetic variants (single nucleotide polymorphisms--SNPs) in genes related to antioxidant defence were found to be associated with breast, prostate, lung, pancreatic, colorectal and bladder cancer. However, the results from these have been contradictory. Moreover, it is believed that environmental as well as genetic factors are implicated in the development of cancers, and consequently it is important to assess both genetic (including gene-gene association) and non-genetic (e.g. diet, supplementation, smoking and alcohol consumption) variability in the activities of defence enzymes in relation to cancer. In this review we focus on the biological function of antioxidant defence enzymes, and relationship between well-known SNPs in SOD1, SOD2, CAT, GPX1 and GPX4 genes and genetic susceptibility to cancer.

[Oxidative stress and trace elements affect the activity of sodium transporting systems in a cellular membrane of a erythrocyte]. / Stres oksydacyjny i pierwiastki sladowe wplywaja na aktywnosc systemów transportujacych sód w blonie komórkowej erytrocytu.

We examined the activity of sodium transporting systems (STS) in a cellular membrane of erythrocytes in a group of 21 patients under chronic hemodialysis treatment with the dialyzing fluid containing glucose HD-g(+), and 22 patients dialysed with the fluid not containing glucose HD-g(-), 21 patients with chronic kidney failure already not treated with dialysis and 21 control group. We examined the concentration of antioxidative system cofactors, such as zinc, copper and selenium in erythrocytes and plasma. The marker of oxidative stress in erythrocytes and plasma was the concentration of TBARS. Among all STS we examined the activity of Na(+)/K(+) ATP-ase, Na(+)/K(+)/Cl(-); co-transport, Na(+)/Li(+) exchanger, Na(+), K(+)-outflow. Copper zinc and selenium as cofactors of antioxidative enzymes may reflect the antioxidative processes inside the organism undergoing the influence of free radicals.

Influence of glucose in the dialysate on the activity of erythrocyte-glutathione-peroxidase and blood selenium concentration in hemodialyzed patients.

BACKGROUND: The aim of the study was to show the influence of glucose in the dialysate on the intensity of oxidative stress, activity of glutathione peroxidase (GSHPx) and concentration of selenium in patients undergoing regular hemodialysis. METHODS: The study was comprised of 85 patients hemodialyzed with dialysate containing glucose [HD-g(+)] or not containing glucose [HD-g(-)], patients with chronic renal failure on conservative treatment and control group. The concentrations of the products of reaction with thiobarbituric acid (TBARS), concentration of selenium in erythrocytes and plasma, concentration of copper in erythrocytes and the activity of GSHPx were determined. RESULTS: GSHPx had significantly higher activity in HD-g(-) group before HD than in control group. In HD-g(+) group before hemodialysis, the activity of GSHPx was significantly lower than in the control group. After HD, the activity showed a statistically significant increase. In both hemodialyzed groups, selenium concentration before hemodialysis both in plasma and erythrocytes was significantly lower, compared to control group. In the group of patients with CRF on conservative treatment, selenium concentration in RBC was significantly higher, compared to concentrations obtained in other groups except for control group. The increase of copper concentration in erythrocytes was accompanied by the increase of oxidative stress and increase of TBARS concentration. The opposite relationship was observed for selenium-its concentration was inversely correlated to copper concentration. CONCLUSIONS: In both groups of hemodialyzed patients, hemodialysis caused the increase of GSHPx in erythrocyte activity and increase of plasma and erythrocyte selenium concentration.

[Atherogenic trans isomers of fatty acids in some food products]. / Wystepowanie aterogennych kwasów tluszczowych izomerii trans w niektórych produktach spozywczych.

OBJECTIVE: Trans isomers of fatty acids (TFA) contain double bonds in their molecular structure with the trans configuration. Food products prominent for their TFA content include plant oils (margarine), mayonnaise, products baked with plant oils, and ready-made glazes and icings. The so-called fast foods and snacks (bars, chips) represent a significant source of TFA, particularly for children and youth. Considering the potentially atherogenic properties of TFA, this work was undertaken to determine the content of the principal monounsaturated TFA in some food products ubiquitous on the market, i.e. margarines and snacks. MATERIAL AND METHODS: We studied bars (Snickers, Mars, Twix), chips (Lay's, Snack, Cheetos), and margarines (Rama Classic, Rama Olivio, Vita, Flora, Finea, Delma, Masmix, Krówka, Smakowita with butter, Extra Pomorskie). The content of TFA was determined with gas chromatography. RESULTS: The highest content ofmonounsatured TFA among sweets was disclosed for the Twix bar (2.94 microg/g), while the lowest for Snickers (0.3 microg/g). Among margarines, the highest content of TFA was found for Smakowita with butter (87.6 microg/g), Krówka (46 microg/g), and Vita (38.7 microg/g), whereas the content was lowest in Finea (0.12 microg/g) and Delma (0.14 microg/g). In the case of chips, the content was highest for Cheetos (3.5 microg/g) and lowest for Snack (0.09 microg/g). CONCLUSIONS: The content of atherogenic TFA in common food products varies widely. In some cases, the content of TFA is considerable and unjustly undisclosed by manufacturers. Promotion of these products should include information in respect of TFA. This conclusion is of particular importance considering the significance of these products in the diet of children and youth.

Copper modifies the activity of sodium-transporting systems in erythrocyte membrane in patients with essential hypertension.

The aim of the study was to verify the hypothesis if copper could influence the activity of sodium-transporting systems in erythrocyte membrane that could be related to essential hypertension. The examined group of patients consisted of 15 men with hypertension. The control group was 11 healthy male volunteers. The Na+/H+ exchanger (NHE) activity in erythrocytes was determined according to Orlov et al. The activity of transporting systems (ATP-Na+/K+; co-Na+/K+/Cl-; ex-Na+/Li+; free Na+ and K+ outflow [Na+, K+-outflow]) was determined according to Garay's method. The concentration of copper in plasma was assessed using atomic absorption spectrometry. The activity of ATP-Na+/K+ (micromol/L red blood cells [RBCs]/h) in hypertensive patients was 2231.5 +/- 657.6 vs 1750.5 +/- 291 in the control (p < 0.05), the activity of co-Na+/K+/Cl- (micromol/L RBCs/h) in hypertensives was 171.3 +/- 77.9 vs 150.7 +/- 53.9 in the control (NS). Na+-outflow (micromol/L RBCs/h) in hypertensives was 118.3 +/- 51.6 vs 113.3 +/- 24.4 in the control (NS). The K+-outflow (micromol/L RBCs/h) in hypertensives was 1361.7 +/- 545.4 vs 1035.6 +/- 188.3 in the control (NS). The activity of ex-Na+/Li+ (micromol/L RBCs/h) in hypertensive patients was 266.1 +/- 76.1 vs 204.1 +/- 71.6 in the control (p < 0.05). NHE activity (mmol/L RBCs/h) in hypertensives was 9.7 +/- 2.96 vs 7.7 +/- 1.33 in the control (p < 0.05). In hypertensive patients, negative correlation was found between the activity of Na+/K+/Cl- co-transport and plasma copper concentration (Rs = -0.579, p < 0.05) and between the activity of ex-Na+/Li+ and plasma copper concentration (Rs = -0.508, p < 0.05). Plasma copper concentration significantly influences the activity of sodium transporting systems in erythrocyte membrane. Copper supplementation could be expected to provide therapeutic benefits for hypertensive patients.

Do trace elements modify the activity of erythrocyte sodium-proton exchanger in hemodialyzed patients?

The kinetics (Vmax and Km) of the erythrocyte Na+-H+ exchanger was studied in a group of 21 patients undergoing regular hemodialysis (HD) and in 21 control subjects. The activity of antioxidative enzymes--superoxide dismutase and glutathione peroxidase--as well as the concentrations of their cofactors--zinc, copper, and selenium--in plasma and in erythrocytes were determined. The thiobarbituric acid-reactive substances (TBARS) concentration served as an indicator of oxidative stress intensity in plasma and erythrocytes. It was found that in the control group the concentration of copper in erythrocytes was positively correlated with Km and Vmax. When the concentration of copper increased, the shape of the kinetic curve changed from sigmoidal to hyperbolic. In the control group, the concentration of zinc in erythrocytes also correlated with Km. However, the results obtained for the group of hemodialyzed patients were the opposite: when the erythrocyte concentration of copper increased, a Km decline was observed and the shape of the curve changed from hyperbolic to sigmoidal. In the group of hemodialyzed patients, we also found a positive correlation between Km and the concentration of selenium in erythrocytes, and a negative correlation between Km and erythrocyte TBARS.