[Effect of vitamin E on erythrocyte enzymes and total antioxidant status in diabetic patients with ischemic heart disease]. / Dejstvo vitamina E na enzime eritrocita i ukupni antioksidantni status kod dijabeticnih bolesnika s ishemijskom bolescu srca.

Lipid peroxidation is thought to be one of the major factors involved in atherogenesis. There is an increasing evidence is increasing that oxidation of LDL cholesterol may be instrumental in atherogenesis. Diabetics are known to be at increased risk of cardiovascular diseases, a phenomenon which has previously been linked to the lipid peroxidation process. As a result, a number of studies have been undertaken to evaluate the effects of antioxidant vitamins on coronary heart disease and risks factors of ischaemic heart disease such as diabetes mellitus. Lipid peroxidation and antioxidant status were studied in 51 patients with ischaemic heart disease and some of with having diabetes mellitus (18%). Results were compared before and after supplementation of 450 mg of tocopherol acetate for three months. SOD were found to be elevated in patients with diabetes and in whole groups of patients after supplementation of tocopherol acetate. Also, TAS was found to be elevated in a subgroup of patients without diabetes and no significant changes were found in glutathion-peroxidase after supplementation. We found statistically significantly decreased mean values of glucose after supplementation in all groups of patients. The monitoring of antioxidant parameters in diabetic patients could be of vital importance in the study of the disease.

Interaction between L-arginine: no system and cyclooxygenase metabolic products of arachidonic acid in coronary autoregulation.

Coronary autoregulation (CA) is the intrinsic ability of the heart to maintain its nutritive blood supply constant over a wide range of perfusion pressure. This phenomenon is regulated through several control mechanisms, while metabolic and myogenic control mechanism have dominant effects. In last few years, endothelial control mechanism, which is part of metabolic control, was intensive investigated. Dominant topic of endothelial-investigation was bioregulatory L-arginine: NO system, with his effective product--nitric oxide (NO). On the other hand, cyclooxygenase metabolic pathway products of arachidonic acid plays an important role in the control of vasomotor tone of coronary arteries. For this purpose, the aim of our study was to evaluate role of L-arginine: NO system, cyclooxygenase metabolites of arachidonic acid, as well as, their interactions in the control of CA of the isolated rat heart.. In our study rat hearts autoregulate CF between 50 and 90 cm H2O of CPP. Basal release (at 60 cm H2O) of NO (as nitrite), cAMP, cGMP and HX+X (i.e. adenosine) amounted to 2.85+/-0.25 nmol/min/g wt, 29.45+/-2.22 pmol/min/g wt, 0.43+/-0.08 pmol/min/g wt and 37.50+/-2.89 nmol/min/g wt respectively. Release of NO, cAMP and cGMP were strictly parallel with CPP-CF curve, while release of adenosine (i.e. HX + X) was an inverse function of perfusion pressure. Inhibition of NOS (L-NAME, 30 micromol/l) significantly widened autoregulatory range (40-100 cm H2O), with significant reduction in CF and NO- and cGMP release, while release of cAMP was completely reversed in the presence of L-NAME. However, inhibition of cyclooxygenase didn't influence autoregulatory range, with similar changes of NO- and cAMP-release and completely inversed values of released adenosine. When L-NAME an indomethacin (an nonspecific COX-inhibitor), 3 micromol/l where added together, they exhibit interactions between these two enzymatic systems. Namely, when L-NAME was added first, indomethacin didn't influence hemodynamic effects of NOS-inhibitor. On the other hand, when COX-inhibitor was added first, L-NAME widened autoregulatory range in small manner as after control autoregulatory experiments (40-90 cm H2O). All hemodynamic changes were followed with similar changes in NO-release, what suggest that exist interaction between L-arginine: NO system and COX-metabolites in the regulation of coronary autoregulation.

Enhanced erythropoietin and prostaglandin E production in the dog following renal artery constriction.

Renal artery constriction (RAC) to 30% of normal flow for 12 hr in the unilaterally nephrectomized dog produced a marked increase in both erythropoietin titers and prostaglandin E (PGE) levels in the blood. In dogs pretreated prior to RAC with indomethacin, a potent inhibitor of prostaglandin synthetase, there was no significant increase in either PGE or erythropoietin levels as compared to zero-time control values. These data suggested an involvement of renal PGE in the generation of erythropoietin following RAC.