Biochemical evaluation of oxidative stress during exercise in patients with coronary heart disease.

The impact of exercise tolerance test on oxidative stress was assessed by thiobarbituric acid reactive substances and markers of antioxidant status, namely Cu Zn superoxide dismutase, glutathione peroxidase, glutathione and vitamin E in blood samples of patients with exertional angina. The study was aimed to differentiate patients with positive exercise test (coronary heart disease patients) from patients with negative exercise test, at rest and peak exercise with respect to the investigated variables. Significantly lower values for both glutathione peroxidase activity and glutathione level were observed in patients after exercise test (p<0.01 and p<0.05, respectively). Only the patients with positive exercise test had significantly lower values for Cu Zn superoxide dismutase, glutathione peroxidase and glutathione, and a significantly higher ratio of thiobarbituric acid reactive substances/glutathione after exercise, as compared to before (p<0.05, p<0.05, p<0.05, p<0.01, respectively). Our findings indicate that the exercise test applied to patients with exertional angina oxidatively stresses the erythrocytes to a greater extent in exercise test (+) patients than in exercise test (-) patients.

Circulatory changes in acute glomerulonephritis at rest and during exercise.

In order to evaluate the effects of acute glomerulonephritis on the circulation, 6 patients were investigated at rest and during moderate exercise. With the patients in a state of rest the cardiac index and the stroke volume index were significantly higher in acute glomerulonephritis than normal, despite significantly raised right and left atrial pressures. Oxygen consumption was significantly increased (P less than 0.01) and the arteriovenous oxygen difference was narrowed significantly (P less than 0.001) in acute glomerulonephritis as compared to normal subjects. The calculated increase in cardiac output was due to both a rise in oxygen consumption and a narrowing of arteriovenous oxygen difference, the latter being more significant. The exercise-induced changes in cardiac output in the patients with glomerulonephritis were not different from those in normal subjects. These results showed that the circulatory changes in the oliguric stage of acute glomerulonephritis resemble those in the hyperkinetic states; the raised mean right atrial and pulmonary wedge pressures do not indicate the presence of heart failure when resting cardiac output is above normal level and response to exercise is normal.