Exercise-induced changes in redox status of elite karate athletes.

Regular training has been claimed to increase the activity of antioxidant enzymes and, consequently, augments the resistance to oxidative stress; however, large volumes of training performed by elite sportsmen could lead to a chronic oxidative stress state. The aim of our study was to assess the oxidative status of elite athletes at the beginning of the preparatory and the beginning of the competition training phases, so that the influence of three months of programmed physical activity on redox status could be determined. The chronic effects of exercise on the redox state of the athletes were compared to the effects of a single bout of karate training. Thirty elite karate athletes, 16-30 years old, were subjected to maximal graded exercise test to estimate their aerobic capacity; blood sampling was also performed to measure levels of superoxide anion radical (O2⁻), hydrogen peroxide (H2O2), superoxide dismutase activity (SOD) and catalase activity (CAT). The only significant change after the three-month training process was found in the significantly decreased CAT activity (X ± SE: 7.95 ± 0.13 U/g Hb × 10³ in the preparatory period, 6.65 ± 0.28 U/g Hb × 10³ in the competition stage; P < 0.01). After a single karate training session, there was statistically significant decrease of O2⁻(X ± SE: 32.7 ± 4.9 nmol/ml in the preparatory period, 24.5 ± 2.5 nmol/ml in the competition stage; P < 0.05) and increase of H2O2(X ± SE: 11.8 ± 1.0 nmol/ml in the preparatory period, 14.2 ± 0.9 nmol/ml in the competition stage; P < 0.01), as well as significant CAT increase (X ± SE: 6.6 ± 0.6 U/g Hb × 10³ in the preparatory period, 8.5 ± 0.5 U/g Hb × 10³ in the competition stage; P < 0.05). Although the three-month training process induced, at the first sight, negative changes in the redox state, expressed through the decrease in CAT activity, adequate response of the antioxidant system of our athletes to acute exercise was preserved.

[Oxidative status evaluation in elite karate athletes during training process].

BACKGROUND/AIM: Oxidative stress is a state of disturbed balance between reactive oxygen species (ROS) and reactive nitrogen species (RNS) on the one hand, and antioxidative defense on the other. As a result of oxidative stress we have irreversible changes in cell function leading to pathological tissue changes, development of many diseases and fast aging process. Increased consumption of oxygen during exercise could be the cause of oxidative stress. The aim of the study was to establish oxidative status of elite karate athletes in the state of rest and after the loading, monitoring the parameters of oxidative stress and components of antioxidative defense in a training process. METHODS: During training process, a group of 30 elite karate athletes was included in the study of prevalence. They were males, from 16 to 30 years of age. The examination was conducted both in resting condition and after the loading. Oxidative status was determined by the level of superoxide anion radical (O2-), hydrogen peroxide (H2O2) as prooxidants, and enzymes of the antioxidant defanse system: superoxide dismutase (SOD) and catalase (CAT). RESULTS: There was a homogenous group of young athletes of normal weight and fats percentage. A significant decrease of O2- after the load was founded, while the levels of H2O2 was significantly increased. Activity of SOD was not significantly changed after exsercise while that of CAT was significantly increased. CONCLUSION: In the long run a programmed physical exercise does not lead to oxidative stress, but an excessive physical load may cause its occurrence.

Evaluation of myocardial relaxation in conditions of cardiac remodeling.

The term cardiodynamics refers to dynamic events associated with cardiac contraction and relaxation. The occurring wave of excitement spreads very quickly along the entire atrial musculature and after a brief AV retention it affects all muscle cells of the ventricles. Excitation, that is, the increase in action potentials, precedes the contraction of the myocardium, which follows the "all or none" rule. Each contraction results in relaxation of the myocardium, so that the contraction and relaxation cycles continually follow each other in succession. The entire cardiodynamics, hemnodinamics, i.e., signaling mechanisms of the heart are altered in the remodeling (alternation) condition of the left ventricular myocardium, i.e., the musculature and the whole arterial wall. Remodeling of the cardiac wall and layers of the arterial wall is a negative factor, because it leads to disturbances of the cardiac contraction and relaxation cycles and incites progression of the arterial hypertension, emergence of atherosclerosis and arterial stenosis. Today, the genetic base of the cardiac remodeling is the object of intensive studies. Cardiomyopathies are primary disorders of the myocardium associated with abnormalities of the cardiac wall thickness, the size of chambers, contractions, relaxations, signal conduct and rhythm. They are the major cause of morbidity and mortality for all age groups. Mechanisms of these events on the molecular level will be discussed in the following study.

[The use of combined hyperbaric oxygenation and erythropoietin in the treatment of cardiac insufficiency].

INTRODUCTION: The aim of this research is to evaluate therapy efficiacy of hyperbaric oxgenation (HBO) with regenerative effects on human tissues and erythropoietin, as a nonspecific growth factor. MATERIAL AND METHODS: This study included a group of 9 patients with echocardiographically diagnosed cardiac insufficiency with ejection firaction (EF%) under 60%. HBO was used according to the protocol for patients with severe cardiac insufficiency (a total of 15 treatments). All patients also received subcutaneous erythropoietin, 2000 i.v., every other day. Control echocardiography was done 30-45 days after they finished their treatments. RESULTS: The average ejection fraction before treatment was 46%. After treatment, the average EF% was 57%, so it increased by 11%. All patients felt subjectively better, with improved capacity to physical efforts. DISCUSSION AND CONCLUSION: Ejection fraction of 30-40% is an indication for hyperbaric oxygenation therapy. The decision about the treatment is made by the physician based on his experience, general condition of the patient, frequency and severity of hypoxic episodes. If EF% is 30% or below, HBO is not recommended, because antioxidative defense mechanisms are exhausted under hyypoxia and the balance of the organism should not be changed. An increase in average EF% by 11% demonstrates that combined use of HBO and Erythropoietin gives good results.

Prostacyclin reduces incidence of myocardial damage after coronary endarterectomy.

BACKGROUND: After coronary endarterectomy, patients have an increased incidence of perioperative myocardial infarction. This study was undertaken to evaluate the possible reduction of perioperative myocardial damage after coronary endarterectomy by intravenous utilization of prostacyclin. METHODS: Elective coronary artery bypass grafting was performed in 1,190 patients with diffuse and distal coronary artery disease, in whom endarterectomy of one or more vessels was used as a treatment. All procedures were done with cardiopulmonary bypass. There were 584 patients in the prostacyclin-treated group, and 606 patients in the control group. Prostacyclin (10 ng x kg(-1) x min(-1)) was started 20 minutes before the cross-clamp removal, or at the time of rewarming, and was continued during the first 24 hours after surgery. The incidence of perioperative myocardial damage was detected by creatine kinase-MB enzyme measurement, and electrocardiographic and left ventricular function changes. RESULTS: A significant decrease in perioperative myocardial damage was detected in the group treated with prostacyclin with respect to the control group. CONCLUSIONS: Prostacyclin infusion initiated during revascularization and continued in the early postoperative course could be successfully employed for the prevention of thrombocyte aggregation and potentially decrease the overall incidence of significant myocardial damage after coronary endarterectomy.

[Effects of platelet single passage on coronary circulation in the isolated guinea-pig heart: focus on the L-arginine: nitric oxide system]. / Efekat jednokratne pasaze trombocita na koronarnu cirkulaciju izolov anog srca zamorceta: fokus na l-arginin:NO sistem.

INTRODUCTION: In order to evaluate endothelial response to platelet single passage through coronary vascular bed, experiments on isolated guinea-pig hearts perfused by the Langendorff method at constant pressure were performed. MATERIAL AND METHODS: Platelet single passage was performed with platelet-rich plasma obtained from healthy volunteers, as well as from patients with acute myocardial infarction. Hearts, isolated from guinea-pigs of either sex were perfused with Krebs-Hensenleit buffer. After a stabilization period of 30 minutes at 70 cm H2O, coronary perfusion pressure decreased to 30 cm H2O and increased to 120 cm H2O. After basic protocol, hearts were perfused with PRP, PRP-AMI alone or in combination with nitric oxide synthase inhibitor, N(omega)-nitro-L arginine methyl ester (L-NAME)--30 M, and nitrite outflow (NO2-) was measured. RESULTS: Basal (at 70 cm H2O) coronary flow (CF) and NO2- was 4.71+/-0.43 ml/min and 0.55+/-0.13 nmol/min/g wt. PRP induced significant decrease of CF at all values of CPP (from 32% at 30 cm H2O to 27% at 120 cm H2O), with parallel NO2- reduction (from 25% to 28%). When L-NAME, 30 M was added, PRP was much less effective: CF was reduced from 13% to 5%, with parallel changes of NO2- (reduction of 10% at all CPP values). PRP-AMI induced higher degree of CF reduction (from 42% to 44%) with NO2 reduction from 23% to 35%. PRP-AMI after applied L-NAME induced also less CF-reduction (from 18% to 12%), with similar NO2- reduction (from 18% to 12%). CONCLUSION: Our findings show that effects of platelet single passage through coronary vascular bed should be affected by NO in isolated guinea-pig hearts.