Blood antioxidant status in road cyclists during progressive (VO2max) and constant cyclist intensity test (MLSS).

AIM: The aim of the study was to evaluate the effect of two different cycling intensities on the blood antioxidant status in seven road cyclists male (M) (age 25.6±4.9 years; height 1.8±0.0 m; body mass 72.4±3.4 kg, and VO2max 66.8±8.9 mL*kg-1*min-1) and six road cyclists females (F) (age 26.5±2.5 years; height 1.67 ±0.01 m; body mass 56.5±5.3 kg; and VO2max 57.2±4.1 mL*kg-1*min-1). METHODS: The experiment was carried out with two tests: a progressive test (VO2max) (TP), and a 30-minute submaximal steady state test (TMLSS). The activity of superoxide dismutase, catalase (CAT), glutathione peroxidase, glutathione reductase, and creatine kinase, and the concentration of uric acid, reduced glutathione, malondialdehyde (MDA), blood lactate as well as total antioxidant potential, were assayed. RESULTS: Exercise significantly differentiated the activity and level of antioxidants. In both tests, after exercise a significant increase of CAT (P≤0.05) and CK (P≤0.05) activity was observed, as well as MDA (P≤0.05) level. CONCLUSION: It was demonstrated that neither the type of test (TP, TMLSS) nor the sex of the subjects exerted significant influence upon the activity of antioxidant enzymes and the level of low molecular weight antioxidants. Due to the workload in road cycling, where an average race or stage lasts a few hours, the 30-minute test was probably too weak a stimulus for the organism to disturb the pro- and antioxidative homeostasis.

[Transformation reactions of special metals in organisms and in the environment. 2. Abiotic methylation reactions of mercury, especially by methyltin compounds and humic and fulvic acids]. / Transformationsreaktionen ausgewählter Metalle in Organismen und in der Umwelt. 2. Mitt. Abiotische Methylierungsreaktionen von Quecksilber, insbesondere durch Methylzinn-Verbindungen und Humin- und Fulvinsäuren.

Following a literature survey concerning abiological methylation reactions including transmethylation of mercury we present the results of transmethylation experiments. Model experiments in aqueous solution show an instantaneous methylation of mercuric chloride by mono-, di-, and trimethyltin chloride, the dimethyl compound having the highest rate of formation. The same is valid for similar experiments with soils, in which influences of the kind of soil also play a certain role. The methylation experiments of HgCl2 with humic and fulvic acids isolated from soil yielded positive results only in some few of the extracts and only with humic acid fractions.