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Biomedical subjects

G N Okuneva

Publications and source records attributed to G N Okuneva.

At least 19 recordsLinked to original sources

[Content of microelements in left ventricular myocardium of patients with ischemic heart disease. Data of roentgenofluorescent analysis with the use of synchrotron irradiation].

Contents of 11 microelements (Se, Rb, K, Sr, Ca, Cr, Mn, Fe, Cu, Ni, Zn) in various parts (zone of infarction, of scar, periinfaction zone) of left ventricular myocardium of patients with ischemic heart disease was studied with method of rentgenofluorescent analysis with the use of synchrotron irradiation (overall 2112 analyses). Left ventricular myocardium of victims of accidents without cardiovascular pathology was studied as control. Compared with control dysbalance of various degree was noted in left ventricular myocardium of patients with ischemic heart disease. Four groups of microelements were distinguished: lowered content (Se, Rb, K); close to normal content (Mn, Cu); moderately elevated content (Cr, Sr, Fe); elevated content (Ni, Zn). Several orders of magnitude elevation of Ni and Zn was noted in all parts of left ventricle, especially in the zone of infarction and periinfarction zone.

Female↗

Laser Doppler flowmetry assessment of microcirculation in upper extremities before and in long-term period after harvesting of radial artery.

Radial artery (RA) is rather commonly used as a graft for autoarterial myocardial revascularization. Consequences of RA harvesting for the development of ischemic disturbances in distal hand segments are poorly understood. The paper presents assessment of hand microcirculation (HMC) before and in late postoperative period after RA harvesting with modern precise diagnostic method - laser Doppler flowmetry (LDF). LDF assessment of HMC was carried out in 80 patients with ischemic heart disease (160 hands) to evaluate the possibility of RA harvesting for coronary artery bypass surgery. HMC classification was developed on the base of these measurements: type 1 -normocirculatory HMC: 6.7-17 ml/min/100 g (58%); type 2 - vasospastic HMC: < or = 6.7 ml/min/100 g (20%); type 3 - hyperemic HMC: > or = 17 ml/min/100 g (22%). In 34% of cases preoperative examination revealed microcirculatory asymmetry between right and left hands. Based on preoperative examination results in 22.9% of cases the decision was made to refuse from RA excision because of positive collateral circulation test developed in our Institute (positive decision about Patent award according to appeal No2000122582/14 (023905) from 28.08.2000). In 14 patients (14 upper extremities) HMC was measured before and 1-1.5 years after RA harvesting. After RA excision baseline HMC in operated hand reduced significantly while maximal HMC reserve remained at the level close to preoperative one. Postoperative HNMC alterations evidence of adequate preoperative assessment of hand collateral circulation potential. In case of blood flow asymmetry RA must be taken from the hand with higher blood supply and adequate collateral microcirculation.

Arteriovenous Shunt, Surgical↗

[The study of cerebral oxygenation and central hemodynamics in patients with ischemic heart disease at rest and during physical effort.].

Cerebral oxygenation (rSO(2)) in the region of sagittal sinus and main hemodynamic parameters were measured in 112 patients with ischemic heart disease and class II-III angina. Four groups of patients were distinguished according to degree of rSO(2) lowering. Hemodynamics and oxygen transport function of the blood were proportionally related to degree of rSO(2) lowering. Normal rSO(2) (>70%) and degree lower (70-61%) was associated with predicted (desirable) cerebral blood flow. Lower rSO(2) values (60-50%) were accompanied with increased oxygen utilization (by 20-25%). Critical rSO(2) lowering (below 50%) was associated with>/=75% rise of oxygen utilization what was indicative of decreased brain blood flow and cerebral ischemia.

Cerebrovascular Circulation↗

[Myocardial blood flow in different regions of the heart in patients with ischemic heart disease before and after revascularization].

Laser doppler flowmetry was used for the intraoperative study of myocardial blood flow before and after revascularization in 116 patients with 2-3 vessel coronary artery disease and class II-IV angina. In patients without myocardial infarction, with microfocal myocardial infarction, or operated early after myocardial infarction revascularization caused no significant increase of myocardial blood flow. In patients with macrofocal infarction surgery was associated with significant increase of myocardial blood flow. Efficacy of revascularization could be assessed by lowering of flow gradients between various regions of the myocardium.

Adult↗

[Clinico-physiological assessment of the mechanisms of compensation and paracompensation in patients with mitral stenosis].

The paper presents the results of an examination of 292 patients with Stages II-V mitral stenosis. Clinical, roentgenological, and electrocardiographic characteristics of the defect were analysed. Physical fitness and gas exchange during exercise were studied in 183 patients with Stages III and IV mitral stenosis. The findings were compared with the intensity of tissue oxygen exchange and the levels of myocardial myoglobin. The patients with mitral stenosis exhibited lower exercise tolerance that was more pronounced in Stage IV. The patients also displayed characteristic profound disturbances in work energy regimen, lower reserve potentialities and functional mobility of the cardiorespiratory system. The pronounced changes in the acid-base balance and gas composition of their capillary blood in Stage IV mitral stenosis during exercise may be explained by a sharply marked arteriolar barrier in the pulmonary circulation (a paracompensatory reaction). The comparison of physiological and clinical findings has enabled the relationship of mechanisms responsible for compensation and paracompensation to be evaluated at various stages of mitral stenosis.

Acid-Base Equilibrium↗

[Blood oxygen saturation in various regions of the circulatory system in healthy persons].

The gaseous composition of the blood has been determined in cardiac cavities and major vessels in 180 practically healthy individuals aged from 1 to 30 years, during diagnostic catheterization of the heart. Physiological norms of gaseous composition of the blood in cardiac cavities and in the major blood vessels have been determined. Blood saturation with oxygen in the identical cardiac cavities and the major blood vessels are the same in men and women. The arterial blood having oxygenation below 93% is considered hypoxaemic. Normal figures of oxygenation for venous blood are from 75-84%. Exponential decrease of blood oxygenation with age (arterial and mixed venous) is roughly the same, due to this the arteriovenous difference of oxygenation at rest remains constant and is roughly equal to 20%. Minimum arterio-venous difference in oxygenation is 10%, maximum 40%.

Adolescent↗

[ABO and Rh blood groups in cardiovascular pathology].

A relationship between erythrocytic antigens of the ABO and Rh blood systems and cardiovascular pathology was revealed by comparing the distribution of blood groups in 13,175 patients and 7,800 donors. Prevalence of A gene and Rh+ phenotype in congenital and acquired heart diseases and ischemic heart disease was found. The frequency of B gene is increased in patients with acquired heart diseases.

ABO Blood-Group System↗

[Work capacity of mitral stenosis patients before and after mitral commissurotomy].

Analysis of the working capacity of 1,000 patients who underwent mitral commissurotomy showed that 67.0% of individuals who were operated on for grade III stenosis and 27.99% of those operated on for grade IV stenosis resumed work. Frequent exacerbations of rheumatism and changes in the myocardium and valvular apparatus are among the causes of the decrease in the number of persons who resume work after the operation. Another reason is overestimation of the group of invalidity or its unjustified qualification

Disability Evaluation↗

[Evolution of lesser circulation hypertension in patients with congenital heart defects based on the example of an interventricular septal defect].

The results of direct pressure measurement in pulmonary circulation in 452 patients with ventricular septal defect (216 males and 236 females), whose age ranged from 12 months to 37 years, were analysed. The findings of diagnostic catheterization of the heart in 150 practically healthy persons 12 months to 40 years of age were used to elaborate the normal values of pressure in pulmonary circulation. The results of pressure measurement in pulmonary circulation repeated at intervals of 1 to 6 years in 46 patients with ventricular septal defect, 18 months to 23 years of age, were analysed. Reverse evolution of pressure in pulmonary circulation after surgical rehabilitation was followed up in 85 patients in 1, 2, 3, 5, and 7 years after the operation. At the age of 12 months to 7 years, systolic pressure in the right ventricle and pulmonary artery comes down to a possible minimum due to expenditure of the adaptational reserve. In large ventricular septal defects, however, the organism proves incapable of reducing the pressure in the early and first periods of childhood as a rule, and so the pressure increases throughout life.

Adolescent↗

[Adaptive reactions of the erythrocytes in the evaluation of physical work capacity in patients with tetralogy of Fallot].

One of the leading factors affecting the functional state of the red blood system is arterial hypoxemia. Under such conditions signs of polycythemia are known to appear. At the same time, changes in the quality characteristics of the blood develop in patients with congenital heart diseases (tetralogy of Fallot including). Therefore a study of the physical rehabilitation as a total functional index may describe the adaptation of the body to hypoxemia, the variants and stages of its development. For this purpose the red blood parameters were examined (the content of hemoglobin, the erythrocyte count and their diameter) and the tolerance of physical exercises was tested by ergometry. The data were analyzed with due regard of the age of the patients and the reduction of their capacity for work, as compared to the due level. Stage 1 reduction of the capacity for work was found in patients with high red blood parameters. In groups of patients with Stage 2, 3 and especially 4 reduction of working capacity the red blood indices were significantly reduced. A distinct correlation was revealed between the erythrocyte count and their diameter, on the one hand, and the capacity for work, on the other.

Adaptation, Physiological↗