Uric acid is the final product of human purine metabolism. It was pointed out that this compound acts as an antioxidant and is able to react with reactive oxygen species forming allantoin. Therefore, the measurement of allantoin levels may be used for the determination of oxidative stress in humans. The aim of the study was to clarify the antioxidant effect of uric acid during intense exercise. Whole blood samples were obtained from a group of healthy subjects. Allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes were measured using a HPLC with UV/Vis detection. Statistical significant differences in allantoin and uric acid levels during short-term intense exercise were found. Immediately after intense exercise, the plasma allantoin levels increased on the average of 200 % in comparison to baseline. Plasma uric acid levels increased slowly, at an average of 20 %. On the other hand, there were no significant changes in plasma malondialdehyde. The results suggest that uric acid, important antioxidant, is probably oxidized by reactive oxygen species to allantoin. Therefore allantoin may be suitable candidate for a marker of acute oxidative stress., R. Kanďár, X. Štramová, P. Drábková, J. Křenková., and Obsahuje bibliografii
Various reactive oxygen species (ROS) may be produced from normal biochemical, essential metabolic processes or from external sources as exposure to a variety of agents presented in the environment. Lipids, proteins, carbohydrates and DNA are all capable of reacting with ROS and can be implicated in etiology of various human disorders (rheumatoid arthritis, reperfusion injury, atherosclerosis, lung diseases etc.). In the organism damage by ROS is counteracted with natural antioxidants (glutathione peroxidases, superoxide dismutases, catalase, glutathione, ubiquinol, uric acid, and essential minerals) and nutritional antioxidants from diet (i.e. vitamins E, C, carotenoids). Possible mechanisms of nutritional depletion and side effects of high intake are in the article described., Z. Zadák ... [et al.]., and Obsahuje seznam literatury
In this study we analyzed the effects of melatonin (Mel, 1 mg/kg ip) on behavioral changes as well as cell and oxidative damage prompted by bilaterally olfactory bulbectomy. Olfactory bulbectomy caused an increase in lipid peroxidation products and caspase-3, whereas it prompted a decrease of reduced glutathione (GSH) content and antioxidative enzymes activities. Additionally, olfactory bulbectomy induced behavioral changes characterized by the enhancement of immobility time in the forced swim test and hyperactivity in the open field test. All these changes were normalized by treatment of Mel (14 days). Our data show that Mel has a beneficial neuropsychiatric action against oxidative stress, cell damage and behavior alterations., I. Tasset ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Oxidative stress is a phenomenon associated with imbalance between production of free radicals and reactive metabolites (e.g. superoxide and hydrogen peroxide) and the antioxidant defences. Oxidative stress in individuals with Down syndrome (DS) has been associated with trisomy of the 21st chromosome resulting in DS phenotype as well as with various morphological abnormalities, immune disorders, intellectual disability, premature aging and other biochemical abnormalities. Trisomy 21 in patients with DS results in increased activity of an important antioxidant enzyme Cu/Zn superoxide dismutase (SOD) which gene is located on the 21st chromosome along with other proteins such as transcription factor Ets-2, stress inducing factors (DSCR1) and precursor of beta-amyloid protein responsible for the formation of amyloid plaques in Alzheimer disease. Mentioned proteins are involved in the management of mitochondrial function, thereby promoting mitochondrial theory of aging also in people with DS. In defence against toxic effects of free radicals and their metabolites organism has built antioxidant defence systems. Their lack and reduced function increases oxidative stress resulting in disruption of the structure of important biomolecules, such as proteins, lipids and nucleic acids. This leads to their dysfunctions affecting pathophysiology of organs and the whole organism. This paper examines the impact of antioxidant interventions as well as positive effect of physical exercise on cognitive and learning disabilities of individuals with DS. Potential terapeutic targets on the molecular level (oxidative stress markers, gene for DYRK1A, neutrophic factor BDNF) after intervention of natural polyphenols are also discussed., J. Muchová, I Žitňanová, Z. Ďuračková., and Obsahuje bibliografii
As wine polyphenols were show n to possess many positive effects in mammals, including improvement of vascular function, this study investigated the effect of the Slovak Alibernet red wine extract (AWE) on blood pressure and vascular function in young normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Six weeks old, male, WKY and SHR were treated with AWE for three weeks at the dose of 24.2 mg/kg/day. Blood pressure (BP), determined by tail-cuff plethysmography, was significantly elevated in SHR vs. WKY and AWE failed to affect it. Lipid peroxidation was evaluated by determination of thiobarbituric acid-reactive substances. Vascular function was assessed in rings of the femoral artery using Mulvany-Halpern’s myograph. Maximal endothelium-dependent acetylcholine (ACh)-induced rela xation was reduced in control SHR vs. WKY rats by approximatel y 9.3 %, which was associated with a significant decrease of its NO-independent component. AWE failed to affect maximal AC h-induced relaxation, both its NO-dependent and independen t components, compared to controls of the same genotype. AWE however reduced lipid peroxidation in the left ventricle of both WKY and SHR and in the liver of SHR. In conclusion, three-week administration of AWE failed to reduce BP and to improve endothelial function in the femoral arteries of both genotypes investigated., P. Bališ ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Oxidative stress is a phenomenon associated with pathogenetic mechanisms of several diseases including atherosclerosis, neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease, cancer, diabetes mellitus, inflammatory diseases, as well as psychological diseases or aging processes. Oxidative stress is defined as an imbalance between production of free radicals and reactive metabolites, so-called oxidants, and their elimination by protective mechanisms, referred to as antioxidative systems. This imbalance leads to damage of important biomolecules and organs with potential impact on the whole organism. Oxidative and antioxidative processes are associated with electron transfer influencing the redox state of cells and the organism. The changed redox state stimulates or inhibits activities of various signal proteins, resulting in a changed ability of signal pathways to influence the fate of cells. At present, the opinion that oxidative stress is not always harmful, has been accepted. Depending on the type of oxidants, intensity and time of redox imbalance as well as on the type of cells, oxidative stress can play a role in the regulation of other important processes through modulation of signal pathways, influencing synthesis of antioxidant enzymes, repair processes, inflammation, apoptosis and cell proliferation, and thus processes of malignity. Imprudent administration of antioxidants may therefore have a negative impact on the organism., Z. Ďuračková., and Obsahuje bibliografii a bibliografické odkazy
The aim of this study was to follow up whether the modification of pro-antioxidant status by oral thiol administration such as N- acetylcysteine and α-lipoic acid affects the hematological response. Twenty-eight healthy men participated in two independent experiments. Subjects were randomly assigned to one of four groups: controls (CNAC and CALA ), N-acetylcysteine (NAC) and α-lipoic acid (ALA). 1200 mg of N-acetylcysteine, 600 mg of α-lipoic acid or placebo were administered for 8 days in two doses. NAC or ALA administration significantly elevated plasma total antioxidant stat us (TAS) and reduced protein carbonylation (PC) and lipid peroxidation (TBARS) by more than 30 %. The reduced glutathione (GSH) and hematological parameters changed only in response to NAC administration. NAC significantly elevated the level of GSH (+33 %), EPO (+26 %), Hb (+9 %) and Hct (+9 %) compared with CNAC. The mean corpuscular volume (MCV) and the mean corpuscular hemoglobin (MCH) also increased by more than 12 % after NAC. The numerous negative or positive correlations between the measures of TAS, PC, TBARS and hematological parameters were found, which suggest the NAC-induced interaction between pro-antioxidant and hematological values. Our study has shown that both N-acetylcysteine and α-lipoic acid intake reveal an antioxidant action, but only N-acetylcysteine improves the haematological response., A. Zembron-Lacny ... [et al.]., and Obsahuje seznam literatury
Fat-enriched diet is strongly associated with cataract development. Laurus nobilis shows antioxidant activity. Herein we evaluated the effect of Laurus nobilis oral administration on the blood and lenses antioxidant activity in rabbits under fat-enriched diet. Sixty rabbits divided into 4 groups were used. One group represented the control (N-CTR). The second group (P-CTR) fed a diet supplemented with 2.5 % of pig fat; the third group (EXP1) received a diet supplemented with 2.5 % of pig fat and 1 g/kg of dried-bay leaves; the fourth group (EXP2) was treated with dried-bay leaves at the rate of 1 g/kg of feed. At baseline and at the end of the study (56 days) the following blood parameters were determined: thiobarbituric acid reactive substances (TBARS), reactive oxygen metabolites (ROMs), total phenols, superoxide dismutase (SOD), oxygen radical absorbance capacity (ORACpca), ferric ion reducing antioxidant power (FRAP), retinol and alfa-tocopherol. At the end of the follow-up, the eyes were enucleated and the antioxidant profile, such as total antioxidant activity (TAC), TBARS, retinol and alfa-tocopherol of lenses was evaluated. Plasma ROMs and TBARS levels were statistically lower in the groups receiving bay leaves integration. A significant increase of plasma retinol, FRAP and ORACpca levels was found in EXP1 and EXP2 groups, whereas plasma alfa-tocopherol resulted statistically higher only in EXP2 group. Bay leaves supplementation enhanced TAC, retinol and alfa-tocopherol in rabbit lens, particularly in EXP2 group; whereas lenses TBARS levels significantly decreased in both treated groups. These findings demonstrate that Laurus nobilis oral administration exerts a protective effect on the risk of cataract development in rabbits under fat-enriched diet., D. Casamassima, F. Chiosi, F. Vizzarri, M. Palazzo, C. Costagliola., and Obsahuje bibliografii
Obstructive sleep apnoea syndrome (OSAS) is a common disorder associated with upper airway muscle dysfunction. Agents that improve respiratory muscle performance may have considerable therapeutic value. We examined the effects of acute exposure to sustained and intermittent hypoxia on rat pharyngeal dilator muscle function. Additionally, we sought to test the efficacy of antioxidant treatment in ameliorating or preventing hypoxia-related muscle dysfunction. Isometric contractile and endurance properties of isolated rat sternohyoid muscle bundles were examined at 35 °C in vitro. Muscle bundles were exposed to one of four gas treatments: hyperoxia (control), sustained hypoxia (SH), intermittent hypoxia (IH) or hypoxia/reoxygenation (HR), in the absence or presence of the superoxide scavenger – Tempol (10 mM). Stress-frequency relationship was determined in response to electrical stimulation (10-100 Hz in increments of 10-20 Hz, train duration: 300 ms). Muscle performance was also assessed during repetitive muscle stimulation (40 Hz, 300 ms every 2 s for 2.5 min). Compared to control, IH and HR treatments significantly decreased sternohyoid muscle force. The negative inotropic effect of the two gas protocols was similar, but both were of lesser magnitude than the effects of SH. SH, but not IH and HR, increased muscle fatigue. Tempol significantly increased sensitivity to stimulation in all muscle preparations and caused a leftward shift in the stressfrequency relationship of IH and SH treated muscles. Tempol did not ameliorate sternohyoid muscle fatigue during SH. We conclude that Tempol increases upper airway muscle sensitivity to stimulation but only modestly ameliorates respiratory muscle weakness during intermittent and sustained hypoxic conditions in vitro. Respiratory muscle fatigue during sustained hypoxia appears unrelated to oxidative stress., J. R. Skelly, ... [et al.]., and Obsahuje seznam literatury