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Biomedical subjects

S F Leonova

Publications and source records attributed to S F Leonova.

At least 19 recordsLinked to original sources
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↗
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↗
PubMed1990

Changes in the properties of plasma fibronectin in Shigella-induced endotoxaemia and the responses to hyperbaric oxygenation and indomethacin.

In rabbits, Shigella endotoxin causes hypoxaemia, metabolic acidosis, and hypocapnia. These changes are more marked at a dose of 1 mg kg-1 than with one of 0.5 mg kg-1 body weight. The endotoxin also reduces the plasma level and heparin-binding activity of fibronectin (FN). During convalescence, FN activity recovers at a slower rate than its level. Hyperbaric oxygenation (HBO; 2 atm for 1 h) normalizes blood gas composition and acid-base and electrolyte balance, improves the clinical picture of endotoxaemia, enhances FN activity and, to a lesser degree, its concentration, and lowers mortality. Indomethacin (IN) (5 mg kg-1 orally) has a similar action. When HBO and IN are used in combination, there is no enhancement of the therapeutic effect and mortality increases.

Animals↗
PubMed1990

[Anaerobic threshold levels in the assessment of central and peripheral hemodynamics].

A treadmill test involving a noninvasive evaluation of cardiac pump function and the anaerobic threshold (AT) was performed to examine 110 patients with cardiac malformations, 31 with atherosclerotic lesions in arteries of the lower limbs, and 49 normal subjects. The results were compared with those of direct measurement of blood lactate concentrations. Simultaneously, changes in transcutaneous O2 tension (TcpO2) were recorded in the recovery periods after each exercise stage, recovery of continuous blood flow (td). TcpO2 and td were indicated to reflect AT resulted just from decompensation of cardiac pump function in patients with impaired central hemodynamics. It was ascertained that TcpO2 and td might be objective measures for severity of central or peripheral hemodynamic abnormalities and reflected the levels of AT at systemic, organic, and microcirculatory levels.

Anaerobic Threshold↗
PubMed1989

Hemoperfusion effect on oxygen-carrying function of preserved donor blood and erythrocytic mass.

The purpose of the study was to explore the preserved (7-21 days) donor blood and erythrocytic mass, following perfusion through hemosorbent SKN-D. After the sorption the oxygen-transport function of erythrocytes was found to improve considerably (oxyhemoglobin dissociation curve was shifted to the right on average by 4-4.2 mm Hg). The energy supply became better (ATP level was increased by 38-59%). In view of the above, long-preserved blood and erythrocytic mass following their perfusion through SKN-D hemosorbent can be considered a sufficiently valid transfusion medium.

Biological Transport↗
PubMedDate not supplied

[The diagnostic value of blood rheology studies in cardiac surgical interventions].

The diagnostic value of routine studies of blood rheology in cardiosurgical patients was investigated. Blood rheology, hemostatic system, and acid-base balance were analyzed in 75 cardiosurgical patients during the early postoperative period. In 41 of these the postoperative period was uneventful and 34 patients developed complications. The blood fluidity conditions and estimation of the risk of thrombotic and hemorrhagic complications were assessed using the "Aggregate Status of the Blood" software. The data indicate a high diagnostic and prognostic significance of plasma viscosity, relative blood viscosity, erythrocyte aggregation and deformability indices in evaluation of the status of cardiosurgical patients in early periods after surgery. Application of hemorheological studies as routine methods for examination of patients improved the quality of treatment. Hence, rheological studies of the blood and plasma should become an obligatory component in the diagnosis of the hemostatic status in the early postoperative period after aortocoronary bypass surgery.

Arteries↗
PubMedDate not supplied

[The role of lactate acidosis and enzyme hyperactivity in evaluating hypoxic organ disorders in patients following cardiopulmonary byøass].

One hundred and fifty patients after cardiopulmonary bypass surgery have been examined. It has been shown that overall enzyme activity should be taken into consideration when determining the genesis of postoperative hyperenzymemia and diagnosing the topical (organic) damage. High lactate level (6-8 mmol/l) reflects profound circulatory hypoxia and shows a great likelihood of secondary damage of parenchymatous organs in patients after cardiopulmonary bypass surgery. Marked lactatacidosis combined with a 5-10-fold increase in enzyme activity in the early postoperative period is an unfavourable prognostic sign. Prolonged antagosan (trasilol) administration during cardiopulmonary bypass surgery may be one of the techniques preventing and correcting hypoxic organ damage.

Acidosis, Lactic↗
PubMedDate not supplied

[The status of the renin-angiotensin-aldosterone system in patients in the early period following aortocoronary bypass surgery].

The state of renin-angiotensin-aldosterone system has been studied in 43 patients after aortocoronary bypass surgery. Renin activity, angiotensin II and aldosterone content have been studied, using radioimmunoassay, in comparison with hemodynamic findings and water-electrolyte balance parameters. The study was performed in patients with uncomplicated postoperative period and in patients with acute circulation disturbances just after surgery and 3, 6, 18 and 48 hours after surgical intervention. It has been shown that in uncomplicated postoperative period there is a 6-8-fold increase in plasma renin content and a 1.5-2-fold increase in aldosterone concentration. Despite an increase in aldosterone activity clinical signs of hyperaldosteronism became evident by the 18-48th hour postoperatively. A persistent increase in renin-angiotensin-aldosterone system activity in patients with acute circulation disturbances is considered as a compensatory body reaction directed at stabilization of the circulating blood volume and heart performance.

Adult↗
PubMedDate not supplied

[Dynamics of the level of plasma vasopressin and its role in the regulation of water-electrolyte metabolism in patients following aortocoronary bypass].

Changes in plasma vasopressin, K+, Na levels, osmolality in blood and urine samples, as well as hemodynamic parameters, cardiac output and circulating blood volume including, have been assessed in 38 patients 3, 6, 18 and 48 hours after aortocoronary bypass surgery. It has been found that vasopressin blood level in the postoperative period is considerably (5-7 times) higher than physiological hormone level. The main reasons for vasopressin blood level increase are surgical stress, increase in blood plasma osmolality, hypokalemia, a drop of the arterial blood pressure and central venous pressure elevation. Despite a high vasopressin level and its pronounced impact on the renal excretory function, the first postoperative hours are marked by polyuria, mediated mainly by osmotic diuresis due to infusions of high amounts of osmotically active substances.

Adult↗
PubMedDate not supplied

[Diagnostic value of laboratory indicators in various states of oxygen transport function of the blood in patients, operated on under conditions of cardiopulmonary bypass].

Changes in oxygen and acid-base balance have been studied in 86 patients with different oxygen transport function after cardiopulmonary bypass surgery. It has been shown that diagnostic value of such indexes as SO2 and pO2 in mixed venous blood, O2 consumption and transport, blood and erythrocyte acid-base balance, lactate concentration depends on the cardiac pump function, microcirculatory patterns, pulmonary oxygenation and cell metabolism. In case of acute circulatory disturbances in the early postoperative period the prognostic value of each laboratory finding is in close correlation with the degree of circulatory failure. The observation of changes in oxygen and acid-base balance in the first hours after the operation enables a more accurate diagnosis of disturbances in the inner body medium and a choice of pathogenetically verified methods of their correction in patients after cardiopulmonary bypass surgery to be made.

Blood Chemical Analysis↗