Analysis of Mechanisms Underlying the Development of Endothelial Dysfunction and Functional Disorders in Experimental Diabetes Mellitus and Their Pathogenetic Correction.

On the model of alloxan-induced diabetes mellitus in rats, the development of oxidative stress and violation of the NO-producing function of the endothelium and internal organs was established. Structural changes in the vascular endothelium due to increased level of atherogenic LDL preventing access of L-arginine to endothelial NO synthase (eNOS) contribute to the development of endothelial dysfunction, which is paralleled by oxidative modification of L-arginine and the formation of inhibitors of eNOS expression (asymmetric dimethylarginine, L-NAME). These findings are indicative of reduced eNOS expression in experimental diabetes mellitus. Administration of L-arginine and its combination with L-carnitine caused an increase in the production NO metabolites and eNOS expression levels by 2.13 and 3.8 times, respectively. In parallel, improvement in the electrolyte excretory function of the kidneys, an increase in the Na,K-ATPase activity in organ homogenates, and a decrease in organ-specific enzymes in blood plasma were observed, which indicates the effectiveness of the correction of the identified violations. A way to eliminate metabolic and functional disorders with combinations of L-arginine and L-carnitine is pathogenetically substantiated. This methodological approach can be recommended for the prevention of microvascular complications in patients with type 1 diabetes mellitus.

Analysis of the Mechanisms of Impairment of Functional Parameters of Internal Organs in Saturnism in an Experiment in Rats.

In rats with lead intoxication (intramuscular administration of lead acetate in a dose 5 mg/kg for 30 days), the development of oxidative stress, reduced expression of endothelial NO synthase and total metabolites of NO production, as well as an increased content of norepinephrine were observed. Lead-induced nephropathy developed; diuresis and sodium excretion increased due to a decrease in tubular transport of water and sodium ions. Activation of free-radical reactions in cells of the renal cortex and medulla contributed to inhibition of Na,K-ATPase. LPO caused damage to cardiomyocytes, hepatocytes, which was seen from elevation of AST, ALT, γ-glutamyl transpeptidase, and alkaline phosphatase in the blood serum and a decrease in activity of Na,K-ATPase in the organs tissues. Metabolic disorders revealed in saturnism in experimental rats (LPO activation, reduced expression of endothelial NO synthase and total metabolites of NO, and increased blood norepinephrine) contributed to the development of vascular endothelial dysfunction and hemodynamics disturbances, and damage to cells of internal organs: kidney, myocardium, liver.

Oxidative Stress and Biochemical Markers of Endothelial Dysfunction and Organ Damage under Conditions of Experimental Nonferrous Metal Intoxication.

Chronic nickel intoxication caused by parenteral nickel chloride administration (0.5 mg/kg of body weight) to Wistar rats led to ROS generation inducing LPO in erythrocyte membranes and homogenates of renal, liver, and myocardial tissue. Superoxide dismutase (SOD) activity was inhibited, while catalase activity and ceruloplasmin concentration increased. LPO and its products disrupted nitric oxide production and reduced its bioavailability, which led to the development of endothelial dysfunction and impaired microcirculatory hemodynamics. At the same time, damage of cytoplasmic membranes of internal organs (kidney, liver, and myocardium) was revealed, which was seen from reduced Na+, K+-ATPase activity in homogenates of these organs and increased serum activity of organ-specific (ALT, AST, and γ-glutamyl transpeptidase) and excretory (alkaline phosphatase) enzymes.

[MECHANISMS OF AFOBAZOLE INFLUENCE ON THE NO PRODUCING ENDOTHELIUM FUNCTION AND INDICATORS OF OXIDATIVE STRESS IN RATS WITH EXPERIMENTAL DIABETES MELLITUS.]

Data on the mechanisms of afobazole effect on the NO-producing function of endothelium under conditions of oxidative stress in rats with experimental diabetes mellitus are presents. It is established for the first time that the drug in vivo inhibits the intensity of lipid peroxidation, reduces the concentration of malonic dialdehyde in red blood cells up to 16.07% (p = 0.05), increases superoxide dismutase activity by 13.6% (p = 0.05), and increases the total concentration of nitric oxide metabolites in blood serum by 33.3% (p = 0.001). The drug effect on NO-producing function of endothelium is due to the increased availability of L-arginine to NO-synthase (NOS-3), reduced level of atherogenesis risk factor (LDL cholesterol in serum), and increased expression of NOS-3 in vascular endothelium on the average by 30.5% (p = 0,001).

[Effect of L-carnitine, afobazole and their combination with L-arginine on biochemical and histological indices of endothelial disfunction in cobalt intoxication in rats].

The influence of L-carnitine and afobazole and their combination with L-arginine on biochemical and histological indices of endothelial dysfunction in rats with cobalt intoxication. The obtained data revealed biochemical markers of endothelial dysfunction. Found that-in rats with cobalt intoxication during treatment occurred inhibition of lipid peroxidation (LPO), reduced the concentration of malondialdehyde (MDA) in erythrocytes, activation of superoxide dismutase (SOD). This was accompanied by increased concentrations of nitric oxide (NO), the availability of the substrate L-arginine and possibly the expression of eNOS in the background of L-carnitine and afobazole.

[The changes in the biochemical indices of blood in cobalt intoxication on the background of the regulators of the expression of endothelial NO-synthase].

On the background of chronic cobalt intoxication in rats develops oxidative stress. This is accompanied by a decrease in the content of total metabolites of nitric oxide in the blood serum. The reasons for lower levels of the vasodilatation factor are the following: a deficiency of L-arginine and the increase in the content of the inhibitor of NOS-3. We found a decrease in the bioavailability of nitric oxide due to the increase in the content of oxidized low density lipids, total cholesterol and cholesterol-lowering lipids high density.

Effects of endogenous regulators of endothelial NO synthase on nitric oxide homeostasis and blood serum lipoproteins during experimental diabetes mellitus.

Experimental diabetes mellitus was associated with the development of oxidative stress and a decrease in blood concentration of total nitric oxide (NO) metabolites. Administration of L-arginine induced positive changes in the LPO-antioxidant enzyme system and elevated NO concentration in blood serum, whereas L-NAME, inhibitor of eNOS (NOS-III) increased LPO intensity via SOD inhibition and reduced NO content. Combined administration of Q10 and L-arginine led the suppression of oxidative stress and significant increase in NO level. Combined treatment with Q10 and L-NAME partly abolished the effects of the inhibitor on the parameters of the LPO-antioxidant enzyme system and NO concentration. In all variants of the study, Q10 stimulated eNOS expression and increases NO bioavailability by reducing the levels of total cholesterol and LDL and increasing HDL content in blood serum.

[Influence of combined treatment on biochemical and functional characteristics in patients with vascular complications of type 1 diabetes mellitus and different pathways of compensation].

The study included 39 patients with DM1, symptoms of peripheral diabetic angiopathy and metabolic disorders either compensated, subcompensated or decompensated 20 subjects served as controls. All the patients were given basal therapy with short-acting and intermediate-acting insulins, Some subcompensated patients were treated with hypoglycemic agents in combination with coenzyme Q10. The following parameters were measured: lipid peroxidation, activity of antioxidative enzymes, total nitric oxide (NO) metabolites, cholesterol (CH) metabolism, ALT AST GGT blood flow in the lower extremities was evaluated from rheovasograms. It was shown that patients with decompensated or subcompensated DM1 experienced oxidative stress accompanied by reduced NO levels and bioavailability. Elevated concentration of total CH and LDLP and decreased HDLP levels promoted endothelial dysfunction and were risk factors of atherosclerosis. Traditional therapy relieved disorders of carbohydrate and lipid metabolism but failed to correct hemodynamic disturbances in the lower extremities. Combined treatment with coenzyme Q10 reduced lipid peroxidation, increased activity of antioxidant enzymes, total NO metabolites and bioavailability, decreased the level of atherogenic LDLP. Improvement of metabolism was associated with normalization of elasticity of microvessels and pulse blood filling of the lower limb vessels, reduced tone and modulus of elasticity of arterioles and capillaries, correction of venous hyperemia. Reduced resistance of the microcirculatory bed resulted in normalization of arterial pressure.

Effect of combination therapy with coenzyme Q10 on functional and metabolic parameters in patients with type 1 diabetes mellitus.

Functional state of the kidneys, severity of metabolic disturbances, intensity of LPO, and activity of the antioxidant system in 30 patients (18-36 years old) with type 1 diabetes mellitus and diabetic nephropathy of different compensation were studied before and after standard therapy or combination treatment with coenzyme Q10. Similar parameters were evaluated in 20 healthy subjects of the same age group. The development of metabolic disturbances in patients with type 1 diabetes mellitus (decompensated form) was accompanied by activation of LPO and inhibition of the antioxidant system. These patients were characterized by oxidative stress, diabetic nephropathy with associated proteinuria, and impairment of water excretion, electrolyte excretion, and nitrogen excretion in the kidneys. Combination therapy with coenzyme Q10 had a positive effect on LPO and antioxidant system. This treatment was followed by the relief of hyperglycemia, decrease in the concentrations of glycosylated hemoglobin and LDL cholesterol, and improvement of nitrogen metabolism.

[The influence of afobazole on biochemical and histo-patho-morphological parameters of endothelial function at experimental diabetes mellitis in rats].

Oxidizing stress in rats with experimental diabetes mellitis is accompanied by endothelial dysfunction develops. Its biochemical markers are the increase of concentration of blood MDA, the impairments of cell antioxidant depence and a decrease in concentration of total metabolites of NO and expression of endothelial NO-synthetase (e-NOS). Biochemical changes are considered with histopathomorphologic impairments of aortic endothelium. Treatment with afobazole suppressed free-radical oxidation, increased activity of SOD and concentration of total metabolites of NO and a level of eNOS expression and also restored of a histologic pattern of aortic endothelium due to activation of nucleocytoplasmic regenerative processes.

[Role of free radical oxidation in the development of cardiovascular events in chronic renal failure].

AIM: to refine a role of free radical oxidation (FRO), anemia, and endothelial dysfunction in the development of cardiovascular events in patients with chronic renal failure (CRF) at diferent stages of the disease. SUBJECTS AND METHODS: Eighty-six patients, including 46 (53%) women and 40 (47%) men with Stages II-IV CRF, were examined. The patients' mean age was 43.6 +/- 14 years. Echocardiography, measurements of the blood levels of hemoglobin, albumin, cholesterol, and uric acid, and determination of blood electrolytic composition were made. Blood creatinine concentrations in the group averaged 0.3 mmol/l. Glomerular filtration rate (GFR) calculated from the Cockroft-Goult formula averaged 33.96 +/- 13 ml/min; the duration of CRF was 9.3 +/- 1.6 years. Anemia was detected in 46 (53%) patients. Iron metabolism was estimated from serum ferritin levels. Special studies involved determination of FRO--malondialdehyde (MDA) and the activities of catalase and superoxide dismutase (SOD) in plasma and serum. The plasma concentrations of endohelin-1 (ET-1), thromboxane A2, and prostacyclin were measured by radioimmunoassay. Results. The higher concentrations of MDA and the decreased activities of catalase and SOD, i.e., FRO, correlated with the progression of renal failure. There were also increases in the levels of ET-1 and thromboxane A, and a reduction in the concentration of prostacyclin as blood creatinine levels elevated. Left ventricular hypertrophy was found in 43 (50%) of the 86 patients. Its severity depended on the decrease of creatine phosphokinase and the severity of anemia and arterial hypertension. There was a stable correlation between the changes in left ventricular myocardial mass, MDA levels, and catalase and SOD activities. CONCLUSION: The higher level of MDA and the lower activities of catalase and SOD in patients with CRF, which correlate with diminished renal function, confirm that the disease is closely associated with FRO, that, by aggravating anemia and endothelial dysfunction, affects the magnitude of morphological and functional changes in the cardiovascular system in patients with CRF patients.

[Lipid peroxidation, activity of Na+,k(+) -ATPase and exzymes of antioxidant defence in rats with nephropathy induced by cobalt chloride].

Chronic parenteral administration of cobalt chloride (6 mg/kg) to male rats for 2 weeks or 1 month was accompanied by activation of lipid peroxidation (LPO), a decrease of superoxide dismutase activity and an increase of catalase activity. The membrane toxic action also resulted in a decrease of cortical and medullar Na+,K(+)-ATPase activity of kidneys, and the decrease in renal functions (glomerular filtration, renal water reabsorption, spontaneous diuresis, electrolyte excretion).

[A highly sensitive method of detecting the structural proteins of hepatitis A virus]. / Vysokochuvstvitel'nyi sposob vyiavleniia strukturnykh belkov virusa gepatita A.

A modified technique of protein staining with silver nitrate was employed in electrophoretic analysis of hepatitis A virus structural proteins. The modifications of the original technique, i.e. thorough washing of the gel, increased formaldehyde concentration and a more intensive lighting of the gel, have elevated the method sensitivity 10-fold permitting the detection of up to 0.1 ng protein. The modification has allowed detection of VP1, VP2, and VP3 structural proteins with molecular masses 33, 29, and 27 kD, respectively, in virus preparations of low concentrations.