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Biomedical subjects

V I Mil'chakov

Publications and source records attributed to V I Mil'chakov.

At least 19 recordsLinked to original sources
PubMed2002

[Effects of free oxygen radicals on impaired lung oxygenating function at aortocoronary bypass surgery].

Fifty five patients with coronary heart disease were examined. Of them 10 patients underwent multiple aortocoronary bypass surgery using intrathoracic or radial arteries under natural circulation, 45 had the same surgery under extracorporeal circulation (ECC). In the patients operated on without ECC, increases in active oxygen forms were rather moderate and practically always occurred with enhancement of antioxidative protective enzymes, the oxygen balance of arterial blood was in the normal range during and after surgery. The ECC patients displayed a considerable creatinine phosphokinase (CPK) with a lower antioxidative protection coefficient particularly when ECC was changed to natural circulation and when the lung was involved in circulation. In the postoperative period, the oxygenation index decreased from 1.7 to 1.3 in virtually all patients, the functional shunt rising from 15 to 30%. In 55% of the patients, varying arterial hypoxemia preserved in the early postoperative period. The damaging factors of ECC (hyperoxia, reperfusion syndrome, etc.) that impair the permeability of lung membranes have been shown to contribute to the activation of CPK, which causes early postoperative' arterial hypoxemia in patients operated on for coronary heart diseases.

Adult↗
PubMed2002

[Use of plasmapheresis in the treatment of drug-resistant cardiac arrhythmias].

AIM: To study the therapeutical efficiency of plasmapheresis (PA) in patients with drug-resistant cardiac arrhythmias (CA) and its mechanisms. MATERIALS AND METHODS: Discrete PA sessions were carried out in 56 patients with drug-resistant CA: paroxysmal atrial arrhythmia (AA), ventricular and supraventricular premature contractions, supraventricular tachycardia of various etiology. Biochemical blood values, coagulographic parameters, lipid peroxidation (LPO), the spectrum of nonesterified fatty acids (NEFA), the level of medium-sized molecules were determined, ECG monitoring, EchoCG, and left ventricular radioisotope computed tomography were performed before and after a PA session. RESULTS: PA was effective in 50% of cases. The duration of its effect averaged 3.0 (1.25-5.0) months. PA was more beneficial for patients with IHD, AA with normal left atrial dimensions, and hyperlipidemia. The duration of the effect was significantly higher when antiarrhythmic drug therapy was continued after PA. Due to PA, there were significant decreases in the blood concentrations of cholesterol, medium-sized molecules, malonic dialdehyde (MDA) and in the proportion of polyunsaturated NEFA. The antiarrhythmic effect was associated with the decreases in MDA and NEFA, with a tendency for a reduction in the rate of chemiluminescence. CONCLUSION: PA may be used in the treatment of drug-resistant CA. The most significant mechanism of its antiarrhythmic activity is to recover sensitivity to antiarrhythmics. The intrinsic antiarrhythmic activity may be associated with its effect on NEFA metabolism and LPO; however, its mechanisms await further studies.

Adult↗
PubMed1997

[Myocardial metabolism and functional capacity in various types of cardiac reperfusion].

Myocardial metabolism and function were studied in 128 patients operated on under extracorporeal circulation for acquired heart diseases. Three groups of patients with different types of cardiac reperfusion were analyzed. Controlled (one- and two-stage) reperfusion was carried out with hyperosmotic unified solution 7 minutes before the beginning of blood recirculation and with perfusate after restoration of blood circulation. Reperfusion was spontaneous with perfusate alone in the control group. It was shown that the use of controlled reperfusion permit the negative action of oxygen and thermal shocks on the cold anoxed myocardium to be largely overcome. This is manifested by rather rapid reorganization of myocardial cells to the aerobic pathway, by inhibited activation of free oxygen radicals, by normalization of fluid-and-electrolyte balance, etc. Two-stage reperfusion was most effective in preventing myocardial metabolic disorders, as evidenced by more rare defibrillation to restore cardiac rhythm and less catecholamine uptake than those with one-stage and especially spontaneous reperfusion. With the latter, myocardial metabolic and functional disturbances were more severe and could be corrected only by the end of an operation.

Heart↗
PubMed1992

[Assessment of myocardial function and metabolism in patients during aortocoronary bypass surgery after hypoxia-reoxygenation].

The myocardial function and metabolism were assessed in 12 patients with coronary heart disease intraoperatively during aortocoronary bypass surgery. The antioxidative properties of the blood of the heart were found to become lower along with activated peroxidation after the major stage of an arrested heart operation, that correlated with depressed myocardial function.

Adult↗
PubMed1986

[Contractile function and antioxidative system of the myocardium of the intact rabbit during hyperbaric oxygenation].

Daily exposures of rabbits to the HBO (2 ata, 1 hr) enhanced activity of glutathione-peroxidase for all 28 days of exposure. Other parameters of the antioxidative defence and the contractile function remained unchanged. The 2.5-ata oxygenation sharply reduced the activity of antioxidative enzymes, the antioxidative activity of lipids, and the tissue resistance against the induced peroxide oxidation of lipids. The heart contractile function was obviously worsened. Sites of necrosis appeared in the myocardium tissue. Increase in oxygenation seems to lead to changes of adaptation of the antioxidative system, but the exhaustion of the latter's power reserves potentiates the toxic effect of hyperoxia.

Animals↗
PubMed1984

[Superoxide dismutase inhibition as a prerequisite for disordered myocardial function under oxygen loading].

Changes in the contractility of rabbit myocardium following administration of diethyl dithiocarbamate were studied to determine the role of superoxide dismutase (SOD) in cardiac support function. It was observed that in healthy rabbits, a 50% decrease in the left ventricle SOD level induced by the inhibitor was not followed by any considerable disturbances in myocardial contractility as determined without additional stimulation and load. HBO sessions caused appreciable disorders in heart contractility which could be partly prevented by SOD administration. In rabbits with adrenaline-induced heart lesions, depression of myocardial contractility induced by the inhibitor alone or in combination with intensive oxygenation was also observed.

Animals↗
PubMed1984

[Effect of combined use of hyperbaric oxygenation and alpha-tocopherol on the contractile function and various components of the antioxidant system of the heart after adrenaline lesioning].

A session of hyperbaric oxygenation (HBO) at 2.5 at. abs. conducted for one hour in rabbits with adrenalin heart affection (AHA) immediately after adrenalin administration prevented a decrease in the cardiac contractile function usually developing within two hours after AHA. On the third day of the follow up, rabbits with AHA receiving daily HBO displayed a decrease in the pump and contractile functions as well as in superoxide dismutase (SOD) activity and the antioxidant activity (AOA) of the left ventricle lipids. Combination of HBO sessions with the intra-muscular administration of alpha-tocopherol (50 mg/kg) made the decrease in SOD activity less pronounced and prevented both the fall in lipid AOA and the depression of the heart contractile and pump functions on the third day following AHA. It is suggested that the combined use of HBO and substances increasing the potency of the cell antioxidation system may become one of the principles of reducing HBO side effects and of expanding the potentialities of HBO in treating ischemic and adrenergic heart impairments.

Animals↗
PubMedDate not supplied

[Lipid peroxidation and content of medium weight molecules in heart surgery with artificial blood circulation].

Malonic dialdehyde (MDA), level of medium-weight molecules, and chemiluminescence (CL) of the blood were evaluated in 24 coronary patients during and after aorto-mammary-coronary bypass operations. Time course of MDA concentration, content of medium-weight molecules, and CL extinction rate were similar in all the patients, but the values were higher in the patients with a complicated course of the postoperative period. Significant difference in CL intensity at the beginning of total anesthesia in patients with uneventful and complicated course of the postoperative period recommend this method for prediction of reperfusion complications. In further studies we intend to determine the diagnostically significant differences in the studied parameters and to distinguish the most informative parameters for each stage, for more effective prevention of oxidative stress in cardiosurgical patients subjected to aortocoronary bypass operations.

Adult↗
PubMedDate not supplied

[Free radical damage in the transplanted liver].

The activity of lipid peroxidation (LPO), antiradical characteristics, content of sodium, potassium, magnesium, total and ionized calcium, copper, zink and iron in blood were studied in 12 patients in the course of ortotopic transplantation of the liver. The duration of the operation was on the average 11.5 +/- 1.5 hours, liver-free period 16.4 +/- 52 minutes, blood loss 7.2 +/- 2.5 l. It was discovered that in the liver-free period and in liver reperfusion there was a prominent shift of free radical and antioxidant properties, content of macro- and trace elements of blood. Because the studied parameters returned to the baseline level to the end of the operation the metabolic shifts are thought reversible.

Electrolytes↗
PubMedDate not supplied

[Metabolic aspects of reperfusion syndrome in patients with chronic ischemia of the lower limbs after surgical revascularization].

24 patients with chronic lower limb ischemia were examined during arterial reconstructive surgery and on the first postoperative day. The parameters of acid-base balance, lipid peroxidation and antioxidant system were measured in arterial and venous blood to determine laboratory criteria of the reperfusion syndrome. The arteriovenous oxygen difference decreased after revascularization while chemiluminescence emission, malonic dialdehyde concentration, antioxidant activity coefficient and medium-weight molecules elevated. On the first postoperative day all these parameters recovered but remained higher than their baseline values. These data illustrate excessive production of free oxygen radicals after limb revascularization, which contributes to reperfusion syndrome. Since determination of lipid peroxidation and antioxidant activity is a time-consuming work, levels of medium-weight molecules content in plasma may indicate reperfusion damage to the limb.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Assessment of reperfusion damage to the myocardium by oxygen free radicals in patients with ischemic heart disease subjected to surgery with artificial blood circulation].

The study was performed on 47 patients with ischemic heart disease subjected to aortocoronary bypass surgery. The study has revealed adaptation changes of free-radical blood properties that led to the damage of the myocardium by oxygen free radicals. Blood sampling from the coronary sinus is of greatest diagnostic value, enhancement of antiradical properties of this blood indicate damage of the myocardium. Detection of lactate in coronary blood may be an early sign of hypoxic myocardial damage caused among other reasons by activation of free-radical processes. Abrupt changes from hypoxic to hyperoxic oxygenation may complicate the recovery of cardiac function, while an even regimen of oxygen supply with a certain tendency of hyperoxia and adequate myocardial protection will not promote damage of the myocardium.

Adult↗
PubMedDate not supplied

[Effects of halothane on cerebral blood flow and its protective action in ischemia].

Halothane impact on cerebral blood flow, brain metabolism and its protective effect in ischemia have been assessed in 30 patients operated on for the occlusion of brachiocephalic arteries. The data obtained indicate that additional use of halothane in N2O:O2 anesthesia during reconstructive surgery on brachiocephalic arteries makes it possible to enhance collateral blood flow, increase retrograde pressure, and decrease O2 consumption by the brain, without considerable changes in systemic hemodynamics. In addition, the studies have shown that halothane decreases lipid peroxidation processes.

Adult↗