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Biomedical subjects

V I Shumakov

Publications and source records attributed to V I Shumakov.

At least 37 records · Page 2Linked to original sources
PubMed1999

Adenosine transport in liver before and after organ preservation.

The effect of 24-h cold storage of liver on nucleoside transport was investigated. Nucleoside transport was estimated under conditions when both known types of nucleoside transport, facilitated diffusion and Na+/nucleoside cotransport, were active and when one of these transport mechanisms was inhibited. The rate of adenosine transport was not decreased after long-term cold storage of the liver. Inhibition of one of the transport systems decreased the rate of adenosine uptake before and after preservation of the liver to about the same extent. The adenosine transport rate was maintained during long-term (100 min) liver perfusion ex vivo. Slight activation of energy-dependent transport in the beginning of reperfusion and the slower recovery of this transport after the second transition from Na+-free to Na+-containing perfusion are not regarded as physiologically important because they were observed after changing the ionic content of the extracellular medium. We conclude that the nucleoside transport systems in liver are quite well preserved after 24-h cold storage of the organ.

Adenosine↗
PubMed1999

Surgical treatment of patients with ischemic cardiomyopathy: the significance of right ventricular function.

BACKGROUND: Patients with ischemic cardiomyopathy (ICMP) awaiting heart transplantation (HT) have a high mortality rate, in part because of the lack of donor organs. Given this limitation, we propose to broaden the indications for coronary artery bypass grafting (CABG) in this group and to more accurately select patients with ICMP requiring myocardial revascularization or HT. In this study, we assessed the short and long-term results of CABG in patients with ICMP. We also assessed the role of the right ventricle and the diastolic function of both ventricles in patients with ICMP. Using this information, we propose indications for CABG and/or HT in patients with ICMP. METHODS: We analyzed 49 patients with ICMP undergoing workup as potential heart transplant candidates. The patients were divided into two groups. Group A included 19 patients submitted to isolated CABG based on the preoperative assessment of myocardial viability. Group B consisted of 30 patients determined to be best suited for HT (with five patients actually receiving a donor heart). All patients were assessed by radionuclide ventriculography (RVG) and functional testing in order to assess their myocardial viability. RVGs were obtained prior to coronary bypass as well as at two and twelve months postoperatively. RESULTS: Preoperative data in group A were: left ventricular end-diastolic dimension (LVEDD) 7.0+/-0.32 cm, left ventricular ejection fraction (LVEF) 24.2+/-2.6%, and right ventricular ejection fraction (RVEF) 32.4+/-2.6%. For Group B, LVEDD was 7.7+/-0.29 cm, LVEF was 22+/-2.7%, and RVEF 26+/-2.6%. The operative mortality in group A was 16.6%. Three patients died in the early postoperative period, two of them due to acute cardiac failure, and one due to cerebral complications. The number of grafted arteries was 3.6+/-0.2. One year after coronary artery bypass, the resting LVEF increased to 33.3% (a 36% improvement compared with preoperative, p < 0.001). Three-year survival was 77% in group A and 26.8% in group B. Examination of the myocardial functional state after CABG showed that the LV diastolic and RV systolic parameters statistically improved. The decrease of RVEF was revealed in the orthostatic test in patients (group A) who died after CABG in the early postoperative period, and in group B that correlated with their parameters of the myocardial viability. CONCLUSIONS: CABG in the patients with ICMP significantly increases the functional reserves of the myocardium of both ventricles, mostly because of the improvement in the diastolic function of the LV. In the RV, the systolic function could restore even in the early postoperative period. Preoperative analysis of the parametric images made after orthostatic test and nitroglycerin intake allow prediction, with 85 % sensitivity and 95% specificity, of the areas of the myocardium which will restore their function immediately after CABG ("hibernated myocardium"). The recovery of regional wall motion amplitude and of the response of the myocardium to coronary revascularization could continue during the first year after revascularization ("stunned myocardium "), most often beginning in the LV. The decrease of the EF of the RV as a response to the "unloading" tests could be a result of the disturbance of the ventricles' interaction as well as the spreading of the scarring of the RV myocardium. This decrease could be a predictor of the possible development of the low cardiac output syndrome after CABG.

Adult↗
PubMed1998

An isocratic, reversed-phase HPLC method for the determination of postischemic efflux of purines and pyrimidines during reperfusion of isolated liver.

An isocratic, reversed-phase HPLC method was developed for the determination of the rates of purine and pyrimidine efflux during early reperfusion of isolated organs after non-perfusion cold conservation. The method enables determination of uric acid, cytidine, xanthine, hypoxanthine, uridine, AMP, inosine, and adenosine in liver perfusate using a standard C-18 column (25 cm length). Peaks are resolved by elution with buffer containing 1% acetonitrile, 20 mM potassium citrate (pH 6.25), and 25-55 mM tetramethylammonium. The effects of pH and solvents on peak retention times are described. As an example of the application of the method, the effects of allopurinol on the rates of postischemic efflux of purines and pyrimidines during reperfusion of liver stored in the cold for 24 h in Euro-Collins solution was studied.

Allopurinol↗
PubMed1996

[The importance of the clinical classification of chronic glomerulonephritis for the prognosis of its progression and of the efficacy of therapy].

A significant correlation exists between clinical types of chronic glomerulonephritis (CGN) in a new clinical classification and morphological CGN types according to classification of WHO experts. Rapid progression is significantly correlated with clinicomorphological variants of CGN represented by unfavorable clinical types and unfavorable morphological types. No rapid progression occurred in combination of clinically favourable types and morphologically favourable and unfavorable types. The above classification is recommended for practice.

Adolescent↗
PubMed1995

[The dynamics of the heart contraction rate and arterial pressure during physical loading after a heart transplant].

Compared to healthy controls, patients with transplanted heart have higher baseline heart rate (HR), delayed initial HR reaction, slower changes of HR both during exercise and after it, diminished chronotropic and inotropic reserves. The data obtained contribute to better understanding of physiology of transplanted denervated heart and objective assessment of patients after heart transplantation.

Adolescent↗
PubMed1995

[Indicators of bicycle ergometry after heart transplantation].

Exercise tolerance in postcardiac transplantation patients versus healthy controls was studied at different intervals after the surgery using bicycle ergometry. Being low after the transplantation, exercise tolerance in the patients increased throughout the rehabilitation period but still did not reach the values characteristic for healthy subjects. Initial heart rate in the above patients was higher, while chronotropic and inotropic reserves of the transplanted heart appeared lower than in the controls. The data obtained help objectively assess the condition of the patients with transplanted heart.

Adolescent↗
PubMed1993

[Echocardiographic diagnosis of acute rejection of transplanted heart].

Comparing echocardiographic parameters with endomyocardial biopsy findings in 6 patients with acute crises of mild, moderate, and severe graft rejections and in 2 patients with persistent acute rejection crisis has shown that there are decreases in end-diastolic size and left ventricular end-diastolic ejection fraction volume, an increase in left ventricular myocardial mass, and thickening of the left ventricular posterior wall and ventricular septum, as evidenced by ultrasonic study. Such changes are detected in moderate and severe acute crises of graft rejection. Normalization of ultrasonic parameters of the grafted heart occurs 2-3 weeks after abolition of rejection crisis. A positive dynamics of echocardiographic parameters in persistent acute rejection crises suggests a good prognosis. Echocardiographic monitoring data obtained in the outpatient setting may serve an indication for unplanned endomyocardial biopsy.

Acute Disease↗
PubMed1993

[The selection and preparation of recipients for orthotopic liver transplantation].

Transplantation of the liver, which was performed for the first time in world practice in 1963, employs today the experience in more than 10,000 liver transplantations and solves successfully such scientific-practical problems of this large field as: further improvement in the schemes for selection and preparation of the recipients, improvement of diagnostics and differential diagnostics, and treatment. Since there is neither much experience nor good information on the subject in our country, not all clinics for internal diseases are sufficiently informed. In view of that, there is a growing need in preparation from the psychological standpoint rather than in the selection of patients. The inefficacy of the traditional therapy of chronic hepatic insufficiency created the premises for the search for new methods in the period of complex preparation with the use of modern pathogenetically substantiated technology. This led to wide introduction of auxiliary methods of treatment into the clinic, such as plasmapheresis and hemoperfusion through cryopreserved hepatocytes which, we think, produce good results in preoperative management of the patients. The principal problem of our preoperative management by extracorporeal methods is temporary compensation of the nonfunctioning kidney during the critical period so that its regeneration would attain the minimal volume necessary for maintenance of vital processes. And in this temporary period of "the stage of relative remission" or favorable period transplantation of the liver must be carried out. Extracorporeal methods of blood cleansing in potential recipients with malignant neoplasms in the liver showed quite the reverse, we do not recommend this method for these patients without jaundice.

Adolescent↗
PubMed1992

[Schemes for implanting shovel pumps for assisted circulation].

The authors propose a design of an axial shovel pump for extracorporeal circulation. They show how to introduce it into various cardiovascular segments and make a comparative assessment of its efficacy in relation to the type and severity of heart failure, surgical access, and treatment policy.

Assisted Circulation↗
PubMed1992

[Surgical technique and approaches in orthotopic liver transplantation].

The first clinical experience with orthotopic transplantation of the liver was summarized. Within the period of from February 1990 to May 1991, 8 operations were performed, including one retransplantation of the liver. The peculiarities and variants of surgical technique, general principles of the performance of operation, methods for vascular and biliary reconstruction are presented. After the operation, 3 patients are alive, no surgical complications were observed.

Adult↗