Lipid peroxidation and total glutathione after different intensities of resistance exercise in trained men.

AIM: Since studies on resistance exercise and oxidative stress markers show contradictory results, it is not clear whether different intensities of exercise are the determinant of changes in such markers. The objective of this study was to investigate the acute effects of different intensities of resistance exercise on lipid peroxidation and total glutathione in previously resistance trained men. METHODS: Eight male subjects with at least 2 years of resistance training experience performed two different resistance exercise protocols: low-intensity (LI), 60% of one repetition maximum (1RM) and high-intensity (HI), 85% of 1RM. Both protocols involved seven exercises and subjects performed one set of each exercise. Blood samples were obtained before and immediately after exercise for lipid peroxidation and total glutathione analysis. RESULTS: The results indicated a significant difference in total workload (load multiplied by repetitions performed) between the LI and HI protocols (P<0.05) and no differences on lipid peroxidation and total glutathione after both LI and HI protocols. CONCLUSION: This study suggests that resistance exercise protocols composed of a single set of seven exercises, regardless of the intensity or total workload do not induce to oxidative stress, suggesting that volume is the main variable to induce oxidative stress in previously resistance trained individuals.

Effects of chronic resveratrol supplementation in military firefighters undergo a physical fitness test--a placebo-controlled, double blind study.

PURPOSE: The purpose of this study was to determine the plasma metabolic response and certain indicators of oxidative stress (antioxidant system and oxidative stress biomarkers) in plasma and erythrocytes of Brazilian military firefighters supplemented or not with resveratrol (RES) for 90 days (100 mg/day). The analyses were performed before and after a typical physical fitness test (FT) used to induce oxidative stress. METHODS/RESULTS: In this placebo-controlled double-blinded study, we observed that RES supplementation did not present hepatic consequences compared with the placebo group following analysis of AST, ALT and GGT plasma activities. Plasma glucose and triglycerides levels were increased after the FT in firefighters supplemented with RES but were not elevated at baseline. Neither total nor cholesterol fractions were modified by RES supplementation. CK levels were increased after the firefighters performed the FT; however, no differences were determined between the placebo and RES groups. Ferric-reducing ability of plasma as well as uric acid was increased after the FT, but was not modified by RES supplementation. Plasma oxidative stress biomarkers, such as thiol content, 8-isoprostane and 8OHdG, showed no modifications, while IL-6 and TNF-α were decreased in the RES group after the FT. Among antioxidant enzyme activities determined in erythrocytes from the firefighters, only GPx activity was reduced by RES supplementation both before and after the FT. CONCLUSION: In summary, the most pronounced effect of RES supplementation is its anti-inflammatory effect, which reduced IL-6 and TNF-α level. The FT applied to Brazilian military firefighters was not sufficient to challenge the antioxidant defense systems, and, therefore, 100mg of RES for three months did not induce significant effects.

Phenanthrene decreases neutrophil function by disrupting intracellular redox balance.

The aim of the present work was to evaluate whether the treatment of human neutrophils with phenanthrene (PHN) can alter the phagocytic and microbicidal capacity of these cells by causing a disruption in redox balance. Peripheral neutrophils from healthy subjects were treated for up to 24 h with increasing concentrations of phenanthrene. Phagocytic/microbicidal activities, antioxidant enzymes, oxidative lesions (thiobarbituric acid-reactive substances and protein thiol and carbonyl groups) and redox signaling compounds (intracellular Ca(2+), superoxide, hydrogen peroxide and nitric oxide) were monitored on neutrophils exposed to 10 microg PHN ml(-1). Cell viability decreased abruptly at PHN concentrations above 10 microg ml(-1) (LC50 = 20.86 +/- 0.51 microg ml(-1) and p-sigmoidal slope = 19.88 +/- 10.11). Phagocytic and microbicidal capacities were decreased by 60 and 82%, respectively. Substantial increases in total-/Mn-SOD, catalase, glutathione peroxidase and glutathione reductase activities (by 61, 15, 87, 245 and 70%, respectively) matched the oxidative injury obtained in TBARS (2.5-fold higher) and protein thiol (54% lower). Diminished productions of superoxide by 18% and hydrogen peroxide by 29% were observed in association to exacerbated calcium (27%) and nitric oxide (63%) levels. The data indicate that phenanthrene might be associated with substantial reduction in human neutrophil functions due to severe intracellular redox imbalances.

First isolation of Cryptococcus neoformans var. gattii from a native jungle tree in the Brazilian Amazon rainforest.

Cryptococcus neoformans var. gattii was isolated for the first time from decaying wood in a hollow of a native jungle tree Guettarda acreana, in a wild area of an Amazon rainforest island, in Brazil. The presence of this variety in a virgin environment without either anthropic action or introduced vegetation is discussed with regard to the common knowledge of Cr. neoformans ecology.