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Biomedical subjects

I I Dement'eva

Publications and source records attributed to I I Dement'eva.

At least 19 recordsLinked to original sources
PubMed2002

[Hemorheology and morphofunctional characteristics of blood cells in children with congenital heart defects].

Patients with congenital heart diseases (CHD) aged 4 months to 12 years, hospitalized for surgical treatment, were examined. Complex viscosity of the blood and the constituents of this parameter (dynamic viscosity and elastic component) were evaluated in the range of shift strain corresponding to the range of shift velocities 0.37-500 s-1 at a frequency of 2 Hz. The threshold blood fluidity was estimated for evaluating the conditions under which erythrocyte disaggregation begins. The relationship between blood rheology and morphofunctional characteristics of blood cells was evaluated. In accordance with the findings, the patients were divided into 3 groups with different suspension stability of the blood. In group 1 the threshold fluidity approximated the norm. In group 2 with normal blood rheology the shifts were compensated and regulation of rheology was in general intact. In group 3 the hematocrit values, mean erythrocyte volume, mean concentration of hemoglobin in erythrocyte, leukocyte counts, and complex viscosity of the blood were the highest, while the suspension stability was the lowest, which indicates depletion of the adaptive potential of the organism. Hence, blood rheology in patients with CHD differs by the type of regulation, mechanisms and compensation of changes, and depend largely on the mean erythrocyte volume, mean hemoglobin concentration in erythrocytes, and leukocyte counts.

Blood Cell Count↗
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↗
PubMed2001

[Changes in blood rheological properties and erythrocyte osmotic resistance in activation of free radical processes].

Relationship between serum oxidation of different degree and micro- and macrorheology of the blood and modification of this relationship in the presence of antioxidant alpha-tocopherol were studied. Lipid peroxidation affects blood rheology and erythrocyte osmotic resistance. Erythrocytes are the first to react to increased activity of free radical oxidation and to exhaust their compensatory potential. Plasma viscosity remains stable in serum oxidation of different degree, and therefore erythrocytes are responsible for changes in blood rheology during intensification of free radical oxidation. Moreover, erythrocytes are functionally resistant to oxidative stress in malonic dialdehyde concentrations under 3.62 +/- 0.41 nM/ml. alpha-Tocopherol increases functional resistance of erythrocytes and maybe of protein components of the plasma to damaging action of free radicals.

Antioxidants↗
PubMed2000

Effects of low-density lipoproteins on blood coagulation and fibrinolytic activity.

In vitro experiments showed that copper-oxidized low-density lipoproteins activate factors of the prothrombin complex in the whole blood and inhibit fibrin generation in both blood and plasma. Moreover, oxidized low-density lipoproteins inhibit fibrinolysis and impair the structure of fibrin clot, which results in hypercoagulation.

Blood Coagulation↗
PubMed1999

[Novel method for calculation of hemostatic potential and its clinical applications. 2].

A formula for calculating the hemostatic potential is proposed: HV = -{Ig[(APTT + PTTIS)/(WBCT.Hct)] + IgPF/PT}, where APTT is activated partial thromboplastin time, sec; PTT prothrombin time, sec; IS index of sensitivity of thromboplastin reagent used; WBCT whole blood clotting time after Lee-White, sec; Het hematocrit; PF probability of liquid blood preservation: and PT probability of thrombotic complications. The aim of the study was to evaluate the probability of practical use of the method and its practical potentialities. Statistical analysis (1014 specimens from 402 patients) confirmed the correctness (plausibility) of our concept and of the model of hemostatic potential. Despite the difficulties of calculation, the resultant hemostatic potential value represents the actual conditions of hemostasis in vivo. The physiological norm is represented as small-positive values of hemostatic potential, reflecting the constant "readiness" of blood to coagulation. Time course of hemostatic potential demonstrates the hemostasis status and its stability during various exposures. The homeostatic potential is a value highly sensitive to hemostatic status and outer exposures. Its changes can be used as a criterion of therapy efficacy.

Adult↗
PubMed1998

[Role of academic B.V. Petrovskiĭ in the development of extracorporeal circulation].

The paper shows the role of Academician B.V. Petrovsky and his scientific school in the development of extracorporeal circulation, as well as his ties with S.S. Bryukhonenko (1890-1960), the founder of extracorporeal circulation in Russia. Heart-lung apparatuses were designed with the participation of collaborators of the Surgery Research Center (SRC), Russian Academy of Medical Sciences. A short account is given of the principal aspects of extracorporeal circulation, which have been studied at the SRC, such as protective blood flow distribution, centralization of circulation, the optimal perfusion rate, criteria for adequate extracorporeal circulation, control of blood coagulation and acid-base state, blood concentration, extracorporeal circulation with autooxygenation, hyperbaric perfusion, normothermal perfusion with continuous warm blood cardioplegia).

Extracorporeal Circulation↗
PubMed1998

[Laboratory of rapid diagnosis (validation, purpose, and procedures)].

The authors discuss the problem of decreasing the number of errors in clinical laboratory diagnosis using artificial "neuron network" in which subjective and half-empirical euristics are replaced with objective regulations based on quantitative and logic analysis. The proposed method was used to derive the decisive rules ensuring prediction of outcomes of abdominal surgery. Reliability of prognostic table reflecting the new decisive rules in common form is confirmed by clinical data.

Clinical Laboratory Techniques↗
PubMed1997

[Role of membrane protectors and antioxidants in the process of perfusion and preservation of donor lungs].

Comparative study of the effect of four perfusion and preservation solutions on lung function, conducted in experiments on 69 inbred dogs, revealed the following regular features. Euro-Collins and electrolyte solutions cause a marked increase of the capillary-hydrostatic pressure, a significant decrease of colloido-osmotic pressure of the plasma, and, as a result, reduction of the ient between them. This is manifested by edema of the lungs. The use of LPD solution is attended by moderate edema of the lungs in moderately increased capillary hydrostatic pressure and mildly reduced colloido-osmotic pressure of the plasma. Perfusion and preservation of the lungs with the LPD solution, containing membrane protectors and antioxidants, for 12 hours is marked by practically unchanged indices of capillary-hydrostatic pressure, plasma coloido-osmotic pressure, and the gradient between them. Edema of the lungs does not develop in this case.

Animals↗
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↗
PubMed1997

[Use of software "Aggregate state of the blood" in staged diagnosis and correction of disorders of blood coagulation and rheology].

The "Aggregate State of the Blood" software was created at the National Research Center of Surgery in 1994. The software is intended for comprehensive assessment of the blood fluidity under different conditions of clotting, rheology, and acid-base balance and shows deviations of the detected values from the norm, predicting the risk of thrombotic and/or hemorrhagic complications. From 1994 to 1996, the program was used in more than 1000 patients subjected to cardiopulmonary bypass surgery with complicated and uneventful peri- and postoperative period. The operations were as follows: heart and liver transplantations (19 and 7 cases), intraaortic balloon counterpulsation (16), extracorporeal detoxication (10), acute myocardial infarction (9), etc. The results were compared with the data recorded in case histories of 255 patients who underwent similar operations in 1991-1994. The results of diagnosis and prediction were commented in the protocol for each case. The conclusions were used for therapy or prevention. The incidence of thrombotic and hemorrhagic complications and the DIC syndrome in 1995-1996, when the new software started to be used, was significantly lower than before. The best clinical results were attained in the patients examined before surgery (n = 92). In this group application of the program (and subsequent preventive treatment) helped improve the adaptive potential of the physiological systems maintaining the blood fluidity. This resulted in a lower postoperative blood loss and a lesser incidence of thrombotic and hemorrhagic complications and the DIC syndrome as against the reference group.

Blood Coagulation↗