[Parameters of oxidative stress in patients with cardiopathies]. / Parametre oxidacného stresu u pacientov s kardiopatiami.

BACKGROUND: Routine biochemical parameters in the blood of patients with chronic cardiopathies are nonspecific and of no reliable diagnostic value. OBJECTIVES: Since marked changes of some biochemical blood parameters concerning the oxidative metabolism of the organism were observed in patients with acute myocardial diseases, the aim of this study was to estimate some antioxidant enzyme activities and metabolites in the blood of patients with cardiopathies-diseases with chronic heart failure of unknown origin. METHODS: In 21 hospitalized patients with cardiopathy the venous blood samples were analyzed for plasma levels of thiobarbituric acid reactive substances (TBARS) as representatives of lipid peroxidation, levels of selenium and zinc as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) and reduced glutathione (GSH) level in erythrocytes. RESULTS: Comparing the group of 25 clinically healthy individuals some marked changes in enzyme activities and metabolite levels were found in patients with cardiopathy: a significant increase of plasma TBARS and-on the other hand-markedly decreased activities of SOD and GPX and of GSH level in erythrocytes. Also a decreased plasma selenium level was observed in patients. CONCLUSIONS: A marked decrease of antioxidant enzyme activities and GSH levels suggest a possible drop in total antioxidant status of patients with cardiopathy. Raised TBARS plasma levels might be regarded as a decreased ability of organism to abolish the produced free reactive oxygen forms leading thus to rise in lipoprotein rare.

The blood volume and the renin-angiotensin-aldosterone system following open-heart surgery.

The circulating blood volume changes, plasma electrolytes, aldosterone as well as plasma-renin-activity (PRA) were studied in 14 patients following open-heart surgery with cardiopulmonary bypass (CPB) and in 14 patients following cardiac surgery without CPB. In both the groups a postoperative decrease of circulating blood volume was observed. This decrease occurred in spite of the positive fluid balance, and so a shift of fluid from vascular to extravascular compartment was likely. In the bypass group the plasma aldoserone level rose immediately after the operation and reached the peak on the first postoperative day. In the non-bypass group the aldosterone level started to fall after the operation, and reached the lowest level on the third postoperative day. The pattern of the postoperative PRA changes was almost identical with the aldosterone level changes in both the groups studied, which suggests that the activation of renin-angiotensin-aldosterone axis might be responsible for the observed plasma aldosterone changes.

Resting values of left ventricular work to coronary blood flow ratio in rats exposed to intermittent high altitude hypoxia and swimming.

Total hemodynamic values and left ventricular blood flow were studied using Sapirstein's method of 86Rb uptake in female rats 24 h after a last exposure to high altitude. A stimulated altitude of 1350 m was used, initial exposure being for 30 min, gradually increased by 30 min daily up to 330 min daily for 5 days a week; the total number of exposures was 32. In another animal group the hypobaric exposure was combined with swimming in water at 37 degrees C. In both experimental groups the cardiac output and stroke volume increased, and in rats undergoing swimming the total peripheral resistance decreased as well. In the rats exposed to intermittent hypoxia only, left ventricular blood flow increased by about the same proportion as the cardiac output. The ratio of left ventricular work to coronary blood flow was significantly increased. In rats exposed to the combined influence of hypoxia and swimming, the increase in left ventricular blood flow did not match either the increase in cardiac output, or the weight gain of the left ventricle. The ventricular work to coronary blood flow ratio was the same as in controls.

Correlation of ovarian binding of 125I-HCG with formation of cAMP, estradiol and progesterone during pregnancy.

The content of ovarian gonadotropin receptors in rat was found to change during pregnancy. The specific binding of 125I-HCG to ovarian homogenates rose to its maximal values on days 13 and 16. Thereafter, the binding declined as parturition approached. No consistent changes in responsiveness of rat ovary to LH in synthesis of cAMP and estradiol were observed during pregnancy. Plasma estradiol concentration increased on day 16 and remained high throught days 21 and 22. Progesterone levels increase steadily during the first half of pregnancy and then fall, especially sharply on day 21 and 22. The results demonstrate that the secretion of progesterone correlates with gonadotropin receptors during pregnancy.

Activity of sympathetic nerves in heart during cardiopulmonary bypass in patients.

The sympathetic nerve activity in heart during cardiopulmonary bypass was studied in 20 patients. The rate of release of dopamine-beta-hydroxylase from cardiac nerves was used as an indicator. It was found that the thoracotomy alone does not represent such a stimulus which would lead unambiguously to sympathetic overactivity in heart. Cardiopulmonary bypass represents, on the other hand, an intensive sympathomimetic stimulus, as it was demonstrated by significnat increase of coronary A-V difference negativity of dopamine-beta-hydroxylase as early in 15th minute of its duration. The washout of enzyme to the end of 30 min. duration of bypass still increased. After finishing of bypass the coronary A-V diff. of dopamine-beta-hydroxylase again decreased.

Influence of alpha-adrenergic block and beta-adrenergic stimulation on distribution of cardiac output after cardiopulmonary bypass.

Organ and tissue damage restricts total cardiopulmonary bypass to a few hours in patients. The cause might be the disturbance of tissue flow in which the sympatho-adrenal hyper-activity plays a decisive role. In dogs, killed 30 min after cardiopulmonary bypass was stopped, we studied the tissue distribution of cardiac output with the method of Sapirstein. In one group the alpha-adrenergic blocker, in the other one the beta-adrenergic stimulator was continuously applied during the whole operation-period. Compared to a control group the per cent of cardiac output as well as the regional tissue flow after alpha-adrenergic block increased in the liver, ileum, adrenals, testes, kidney and in the skin and decreased in the spleen and thyroid gland. After beta-adrenergic stimulation the per cent of cardiac output increased in the heart muscle, lungs, liver, ileum, adrenals and m. soleus and decreased in the spleen and thyroid gland. The absolute values of organ tissue flow increased in ileum and decreased in the spleen, thyroid gland and in the kidney.

Activity of catecholamines inactivating enzymes in heart muscle during anoxic cardioplegia in cardiosurgical patients.

On the model of anoxic cardioplegia in cardiosurgical patients the influence of anoxia on the activity of monoamine oxidase (MAO) and catechol-O-methyltransferase (COMPT) in right auricular tissue was studied. It was found out that the activity of COMT does not change during anoxia, the activity of MAO considerably increases. With regard to catecholamines stimulating effect upon cardiac metabolism as well as to their calorigenic and oxygen wasting effect the raise of MAO activity may be regarded as favourable phenomenon, because the hastened degradation of released catecholamines at least to a certain degree diminishes the disproportion between oxygen supply and actual oxygen need of the heart and by means of that mitigates the anoxic damage of myocardium.