[Sevoflurane optimal dosage estimation for myocardium pharmacological postconditioning: an experimental study].

We estimated the optimal dosage of inhalation anesthetic sevoflurane, for the maximum cardioprotective effect with minimal angioparalytic action. 25 pigs were included in this study, they were divided into 5 groups, depending on the sevoflurane dosage used for pharmacological postconditioning (PPC): control group - PPC has't been conducted, a group of PPC 0.5 - sevoflurane PPC in a dose of 0.5 V%, a group of PPC 1.0 - sevoflurane PPC in a dose of 1.0 V%, a group of PPC 1.5 - sevoflurane PPC in a dose of 1.5 V%, a group of PPC 2.0 - sevoflurane PPC in a dose of 2.0 V%, a group of PPC 2.5 - sevoflurane PPC in a dose of 2.5 V%. Ischemia was simulated by left coronary artery crossclamping. Further PPC was held according to the following Protocol: 20 min before left coronary artery clamp off and first 20 min of reperfusion sevoflurane was given into CPB circuit. Myocardial ischemia period was 60 min in all groups. It was found and experimentally proved that the optimal sevoflurane dosage for PPC is 2 V%

[Effect of perfusion volume of the Custodiol solution on the efficiency of cardioplegia in experiment].

The purpose of the present study was to compare the efficiency of small and standard volumes (1.5-20 and 7-10 ml/g of the myocardium, respectively) of Custodiol solution in myocardial ischemia lasting 2 and 4 hours. Experiments were carried out on 24 mongrel dogs weighing 22-36 kg under extracorporeal circulation (EC) with bicaval cannulation under moderate general hypothermia and balanced general intravenous anesthesia. According to the solution volume and cardioplegia (CP) duration, all the animals were divided into 4 groups: 1) 2-hour CP (standard volume); 2) 2-hour CP (small volume); 3) 4-hour CP (standard volume); 4) 4-hour CP (small volume); of them Groups 1 and 3 served as a control. Antegrade CP was accomplished by the conventional procedure. In Groups 1 and 3, the volume of Custodiol solution was 1000-2000 ml; in Groups 2 and 4, that was 300-600 ml depending on myocardial mass. In Groups 1 and 3, the mean duration of myocardial perfusion was 9.8+/-2.8 and 8.4+/-1.4 min, respectively; and in Groups 2 and 4, that was 4.2+/-0.7 and 4.5+/-1.4 min. Groups 3 and 4 animals received additional myocardial perfusion with Custodiol solution in a volume of 400-500 and 200-250 ml, respectively. The efficiency of myocardial protection was evaluated from the course of a reperfusion period (RP) and from central hemodynamic changes, the concentrations of glucose, lactate, malonic dialdehyde, medium-weight molecules, and blood gas and electrolyte composition of the coronary sinus. The studies were performed in stages: outcome, launch of blood flow (5-10 in); RP (30 min); complete loading (30 min); disconnection from an extracorporeal circulation apparatus. The experiment has indicated that the use of Custodiol solution in the standard volumes ensures an effective cardioplegic protection within 4 hours. Reductions in the volume and time of perfusion to the values characteristic of extracellular-type solutions cause a lower efficiency of this protection. Moreover, myocardial damage progresses as the duration of CP increases. The used Custodiol solution dose of 1.5-2.0 ml/g of the myocardium is apparent to be insufficient to set an ionic balance between cardioplegic solution and intracellular fluid, which reduces the duration of CP effect and the efficiency of myocardial protection. It may be assumed that lower perfusion volume lowers the efficiency of the buffer system of the solution and the metabolic effects of substrates. The authors consider that the decreased volume and time of perfusion of intracellular Custodial solution are unjustified and may result in the development of complications associated with inadequate cardioplegic myocardial protection.

[Metabolic aspects of reperfusion syndrome in patients with chronic ischemia of the lower limbs after surgical revascularization]. / Metabolicheskie aspekty reperfuzionnogo sindroma u bol'nykh s khronicheskoi ishemiei nizhnikh konechnostei posle khirurgicheskoi revaskuliarizatsii.

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.

[Effects of free oxygen radicals on impaired lung oxygenating function at aortocoronary bypass surgery]. / Vliianie svobodnykh radikalov kisloroda na narushenie oksigeniruiushchei funktsii legkikh pri operatsiiakh aortokoronarnogo shuntirovaniia.

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.

[Use of plasmapheresis in the treatment of drug-resistant cardiac arrhythmias]. / Ispol'zovanie plazmafereza pri lechenii narushenii ritma serdtsa, rezistentnykh k lekarstvennoi terapii.

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.

[Free radical damage in the transplanted liver]. / Nekotorye aspekty svobodnoradikal'nogo povrezhdeniia transplantirovannoi pecheni.

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.

[Lipid peroxidation and content of medium weight molecules in heart surgery with artificial blood circulation]. / Perekisnoe okislenie lipidov i soderzhanie srednikh molekul pri operatsiiakh na serdtse s iskusstvennym krovoobrashcheniem.

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.

[Water purification for hemodialysis]. / Ochistka vody dlia gemodializa.

An electrodialysis system has been designed to purify water. It comprises two units: a preliminary preparation unit and an electrodialysis one. The system consists of columns containing zeolite, activated carbon, and ion-exchange resins. Zeolite makes water free from mechanical impurities and iron, activated carbon adsorbs organic matter and chlorine ions, ion-exchange resins soften water. The electrodialysis unit is noted for its original design. Mathematical simulation has allowed the authors to optimize the design and to make a block that makes the process continuous without repolarization, which can decant the minimum levels of salt concentrates, thus decreasing energy supply to 2 W per liter. The unit is made as a pressure filter design having the platinum-titanium electrodes and membranes MK-40 and MK-45 made in Russia. The system operates automatically. Its all components are made in Russia.

[Disorders of hemostasis in orthotopic liver transplantation in an experiment]. / Narusheniia gemostaza pri ortotopicheskoi transplantatsii pecheni v éksperimente.

The study was undertaken to examine blood coagulative parameters in experimental orthotopic liver grafting. Plasma hemostatic parameters were studied in animals undergone successful and unsuccessful surgery. The preservation of a graft, anesthetization, and blood-substitute therapy were found to substantially affect the severity of hemostatic disorders. The liver-free period was characterized by changes in the fibrinolytic system and the activity of a plasma coagulation, by enhanced hypocoagulation, and thrombocytopenia. The findings suggest that timely correction of blood coagulative disorders is highly essential in orthotopic liver grafting. Prevention and prompt correction of hypocoagulation and thrombocytopenia are the most urgent.

[Effective method of simultaneous extraction from the urine and purification of tissue kallikrein and acid-stable trypsin inhibitor]. / Effektivnyi sposob odnovremennogo izvlecheniia iz mochi i ochistki tkanevogo kallikreina i kislotostabil'nogo ingibitora tripsina.

A simple preparative procedure is developed for simultaneous isolation from urine of tissue kallikrein and acid stable trypsin inhibitor. The procedure involved adsorption of these proteins on chitosan at pH 5-6 and the subsequent elution with 1 N NH4OH, which enabled to obtain the enzyme and inhibitor with a yield of 80-90% and to purify 10-fold each of these components. Use of chitosan facilitated and simplified distinctly the large scale isolation from urine of the kallikrein and trypsin inhibitor, required for medicinal and diagnostic purposes.