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Biomedical subjects

V G Naumov

Publications and source records attributed to V G Naumov.

At least 19 recordsLinked to original sources

[Effects of digoxin on ventricular arrhythmia in patients with heart failure: relations with the state of the sympathetic-adrenal system].

Ventricular arrhythmias were analysed in 38 patients with Stages I-IIB heart failure from 24-hour Holter monitoring data obtained before and after digoxin therapy by comparing with the concentrations of catecholamines. There was a direct relationship between the plasma levels of epinephrine and norepinephrine and the severity of ventricular arrhythmias, as well as between the changes in cumulative catecholamine levels and ventricular arrhythmias during digoxin therapy. Virtually in all cases, the antiarrhythmic effect of the drug was accompanied by lower plasma catecholamine concentrations whereas the levels of norepinephrine and epinephrine remained nearly unchanged or increased with the tentatively arrhythmogenic action. The findings may suggest that hypercatecholaminemias are essential in the genesis of ventricular arrhythmias in heart failure. Cardiac glycosides can heterogeneously affect ventricular arrhythmias by modifying the activity of the sympathoadrenal system.

Adolescent

[Anti-arrhythmia and hemodynamic effects of allapinin during a course therapy in patients with circulatory failure].

The antiarrhythmic effects of allapinine were studied in 57 patients with chronic circulatory failure (CCF) and cardiac arrhythmias by employing 48-hour Holter monitoring. Allapinine was found to suppress premature ventricular contraction, group premature ventricular contraction and 'runs' of ventricular tachycardia by 82.5, 88.6, and 93.1%, respectively. The antiarrhythmic activity of the agent was more pronounced in patients with coronary heart disease, Stages I-IIA CCF and left ventricular ejection fraction greater than 40%. In addition, in Stages I-IIA CCF allapinine increased myocardial contractility and left ventricular ejection fraction, whereas in Stages IIB-III CCF it showed a slight cardiodepressive effect. Thus, when given in the course therapy in patients with CCF, allapinine has a high antiarrhythmic activity and, to a lesser extent, affects central hemodynamics.

Aconitine

[Cellular mechanisms of impaired cardiac energetics in patients with dilated cardiomyopathy: decrease in mitochondrial respiration and creatine kinase expression].

The mitochondrial functional characteristics were assessed in the biopsy specimens from patients with various Functional Classes dilated cardiomyopathy (DCMP). The assessment was made by using endomyocardial biopsy specimens weighing 2-4 mg which had been taken from 39 patients aged 19-64 years during coronary ventriculography and cardiac transplantation. The status of mitochondria and the efficiency of mitochondrial creatine kinase functioning were evaluated by recording the respiration of saponin-skinned muscular fibers. The maximum mitochondrial respiration rate calculated on a dry weight basis was not substantially different in all functional classes of DCMP, while the acceptor control index (Vmax/V0) and the level of creatine-activated respiration decreased with an increase in the functional class of DCMP. The findings show a good positive correlation between ejection fraction and creatine-stimulated respiration values and a linear negative correlation between this parameter and end-diastolic pressures. Thus, the respiratory parameters of mitochondria in the endomyocardial biopsy specimens may be used to assess the severity of cardias lesions.

Adult

[The radionuclide diagnosis of dilated cardiomyopathy: a new approach to assessing myocardial perfusion function by 201Tl scintigraphic data at rest and during the performance of the dipyridamole test].

A method for quantitative determination of the percentage of left ventricular myocardial 201Tl isotope uptake at rest and during dipyridamole test was first used in patients with dilated cardiomyopathy and coronary heart disease complicated by circulatory insufficiency or chronic myocarditis. This method makes it possible to judge the level of myocardial blood flow and perfusion reserve in these diseases. The most common differences were found between patients with coronary heart disease and those with chronic myocarditis. The patients with chronic myocarditis exhibited the greatest sizes of perfusion defects, highest values of 201Tl uptake at rest and a lower myocardial perfusion reserve during dipyridamole test. In response to exercise, most patients with chronic myocarditis had diminished perfusion defects, whereas those with coronary heart disease displayed increased defects. The myocardial perfusion was varied in patients with dilated cardiomyopathy. Some patients had a scintigraphic pattern close to that in patients with chronic myocarditis and others had a pattern identical to that in patients with coronary heart disease.

Adolescent

Phosphocreatine pathway for energy transport: ADP diffusion and cardiomyopathy.

Chemically skinned (by treatment with saponin, 40 micrograms/ml) isolated cardiomyocytes were used to study the intracellular diffusion of ADP and creatine (Cr). Stimulation of respiration was studied in these cardiomyocytes without intact sarcolemma and in isolated heart mitochondrial by addition of ADP and Cr in the presence of 0.2 mM ATP (via mitochondrial creatine kinase reaction: Cr + MgATP = MgADP + PCr). The Michaelis constant (Km) for Cr was similar in both cases, 5.67 +/- 0.11 (SD) mM in skinned myocytes and 6.9 +/- 0.2 mM in mitochondria, showing that there is no significant restriction to the diffusion of this substrate. However, the apparent Km for external ADP increased from 17.6 +/- 1.0 microM for mitochondria to 250 +/- 38 microM for skinned cardiomyocytes, showing decreased diffusivity of ADP as a result of binding to cellular structures. In the presence of 25 mM Cr, the Km for ADP for myocytes decreased to 35.6 +/- 5.6 microM due to the coupling of the creatine kinase and oxidative phosphorylation reactions. Provision of substrate for the creatine kinase reaction amplified the weak ADP signal in the regulation of respiration. The activity of the mitochondrial creatine kinase was decreased by a factor of two in cardiomyopathic hamsters and human hearts and was associated with a twofold decrease in creatine-stimulated respiration. These data show a potentially key role of mitochondrial creatine kinase in the regulation of cellular respiration and the possible importance of changes in its activity for the functional disturbances of the cardiomyopathic heart.

Adenosine Diphosphate

[The clinical importance of the dynamic determination of the serum neopterin level in patients with dilated cardiomyopathy].

Serum neopterin was measured over time (from 3 to 24 months) by RIA in 15 patients with dilated cardiomyopathy. Comparison with the clinical data revealed that the initially normal concentration of neopterin (less than 9 nM/l) was associated with a stable disease course on a long-term observation (group I). The second group with an initially high neopterin concentration showed an objective improvement of the health status together with normalization of the neopterin level. The third group of patients were characterized by an increase of the neopterin level measured over time, coupled with a disease progress. It should be noted that 5 out of 8 patients died. In addition to neopterin measurements, the patients with dilated cardiomyopathy were examined for serum beta-2-microglobulin (beta-2M). Analysis of the data obtained has demonstrated a similar relationship between the level of neopterin and beta-2M and the clinical course of dilated cardiomyopathy. Still, neopterin is a more sensitive marker. Therefore, the data obtained attest to a possibility of the use of serum neopterin as a prognostic marker in patients suffering from dilated cardiomyopathy.

Adolescent

[Permanent forms of tachyarrhythmia as the possible cause of the development of the dilated cardiomyopathy syndrome].

To specify a possible role played by rhythm disorders in the development of dilated cardiomyopathy (DCM), 9 patients showing permanent sinus and/or supraventricular tachycardia (since birth or within the first 5 years of life) coupled with ventricular rhythm disorders and 11 patients with an assumed infectious disease onset were examined. It has been established that in supraventricular tachycardia, sinus tachycardia included, patients of the child and juvenile age may develop dysfunction of the left ventricle followed by its dilatation which manifests clinically by DCM. The use of antiarrhythmic (cordarone) in such cases may lead to diminution and even to normalization of the heart size and to amelioration of the hemodynamic parameters.

Adolescent

[Serum type III procollagen in dilated cardiomyopathy].

A radioimmunoassay study of procollagen type III end protein (PEP) was conducted in the serum of 11 patients with confirmed dilated cardiomyopathy (DCMP) and 9 patients with coronary heart disease. For DCMP patients PEP levels averaged 8.8 +/- 7.9 micrograms/l, for coronary patients 4.4 +/- 1.6 micrograms/l, in donors 1.7 +/- 1.4 micrograms/l. Thus, the difference between DCMP and coronary patients, donors appeared significant (p less than 0.05). PEP concentrations over 4.5 micrograms/l occurred in 54% of DCMP patients. Growing of PEP turned out most substantial in severe disease (circulatory failure stage IIB-III, pulmonary thromboembolism). Determination of PEP is thought valid for laboratory diagnosis of myocardial inflammation and fibrosis. The discussion covers possible causes and mechanisms underlying high production of PEP from the view point of impaired collagen production.

Adolescent

[Evaluation of the hemodynamic effects of the long-acting peripheral vasodilator flosequinan in patients with chronic heart failure].

The hemodynamic effects of the peripheral vasodilator flosequinan, 100 mg/day, were evaluated in 20 patients with Stage IIA-IIB (the Lang-Strazhesko-Vasilenko classification) heart failure. The doses of digoxin and diuretics were found to be stable. The right cardiac cavities and pulmonary artery were catheterized by Swan-Ganz balloon catheters. The agent was demonstrated to produced profound effects showing decreased pre- and afterload when given both in a single dose or in course therapy.

Adult

[Atrial natriuretic factor in chronic heart failure].

Seventy-six patients with chronic heart failure, stages I-III, that developed after different heart diseases were examined. Catheterization of the right heart was carried out in 51 patients. The concentration of immunoreactive atrial natriuretic factor (ANF) in peripheral blood plasma and in the blood from the right atrium was increased in patients and rose as heart failure progressed. No correlation was discovered between the character of heart disease and the concentration of immunoreactive ANF in the plasma. The latter one was directly dependent on the wedging pressure in the pulmonary artery and on the pressure in the right atrium. The level of immunoreactive ANF in the atrium was higher than in the periphery. However, that was not of statistical power.

Adult

[An attempt to use cordarone in the treatment of rhythm disorders in patients with circulatory insufficiency].

Anti-arrhytmic activity of cordarone was studied in 68 patients with circulatory failure (CF) and heart rhythm disorders with the aid of the 48-hour monitoring of the ECG. Cordarone was administered after the maintenance therapy with digoxin (the mean concentration of digoxin in the plasma 1.38 +/- 0.09 ng/ml) at an average dose of 300 mg/day. Cordarone suppressed supraventricular premature heart beat by 80.2%, ventricular premature heart beat (VPHB) by 76.4%, group VPHB by 82.9% and runnings of ventricular tachycardia by 86.6%. Antiarrhythmic activity of cordarone was more remarkable at the early stages of CF. The concentration of digoxin in the plasma did not exceed the mean therapeutic one. Therefore, cordarone possesses a high antiarrhythmic activity, with its efficacy being significantly higher in patients with moderately pronounced CF. At the same time cordarone influences to a less measure the quality of ventricular rhythm disorders in patients with severe CF and apparently does not avert the cases of sudden death in such patients.

Adolescent

Two-dimensional electrophoresis of heart muscle proteins in human cardiomyopathies.

Human heart muscle proteins have been analyzed by two-dimensional electrophoresis. Twenty five autopsy heart muscle samples obtained from individuals who had died in accidents and who had no signs of cardiovascular pathology have been compared with biopsy and autopsy myocardium samples of patients with: dilated cardiomyopathy (5 cases), hypertrophical cardiomyopathy (2 cases) and myocarditis (2 cases). In dilated cardiomyopathy in 3 out of 5 cases an additional protein spot was found in the myocardial myosin light chain 1 area.

Cardiomyopathies

[Comparative analysis of parametric images in patients with dilated cardiomyopathy and coronary heart disease by radionuclide ventriculography].

After equiponderant radionuclide ventriculography the parametric images (phasic and amplitude) of heart function were estimated in 20 patients with dilated cardiomyopathy and in 17 patients with coronary heart disease associated with cardiomegaly. The patients with dilated cardiomyopathy and those with coronary heart disease showed principal differences in local disturbances of the amplitude of movements of left ventricle myocardium walls. While assessing synchronism of myocardial contraction in the patients with dilated cardiomyopathy the presence of the zones of myocardial asynchronism appeared to be a suggestive sign. At the same time the phenomena of asynchronism were not directly connected with impairment of heart conduction and became aggravated as dilatation of the left ventricle progressed, being often coupled with the ECG signs of cicatrical alterations in the myocardium, which came on the phasic images in the form of dyssynergia areas.

Adult

[Cellular beta-adrenergic receptor complex in patients with heart failure and its changes during digoxin therapy].

Twenty eight males with dilated cardiomyopathy, 5 males with coronary heart disease concurrent with postinfarction cardiosclerosis, 4 males and 2 females with rheumatic heart disease were examined. The findings suggest desensitization of the cellular beta-adrenoreceptor complex in patients with circulatory failure, which appeared as lower beta-adrenoreceptor density with cardiac decompensation progression and impaired transmission of a hormonal signal in the cell, particularly in patients with dilated cardiomyopathy. Digoxin therapy let to an increase in beta-adrenoreceptor density with its initial decrease and to adenylate cyclase activity enhancement. The absence of a positive ++clinico-hemodynamic effect and time course of plasma catecholamine levels in some patients with severe circulatory failure during digoxin use, as well as no changes in the values of the beta-adrenoreceptor adenylate cyclase complex indicate that the abnormalities in beta-adrenergic regulation play an important role in the pathogenesis of refractoriness at the cellular level. Retention of forskolin's stimulant effect allows one to expect a significant positive therapeutic response to be shown with the usage of drugs whose load point is a catalytic subunit of adenylate cyclase.

Adenylyl Cyclases

[Serum neopterin in dilated cardiomyopathy].

RIA was used to measure the level of neopterine and beta 2-microglobulin in the sera of 43 patients with a verified diagnosis of dilated cardiomyopathy (DCMP). In DCMP patients, the mean level of neopterine was 11.25 +/- 1.05 nM/l and was significantly higher than in donors (5.6 +/- 0.5 nM/l). The concentration of neopterine exceeding 9 nM/l was discovered in 55% of DCMP patients. The rise of neopterine concentration was particularly marked in patients with inflammatory reaction in the myocardium according to endomyocardial biopsy. In that patients' group, the mean level of neopterine was 12.9 +/- 2.02 nM/l while the rise of its concentration over 9 nM/l was recorded in 9 (81%) of 11 patients examined. The correlation was established between the rise of the concentration of neopterine and beta 2-microglobulin. In patients with the concentration of neopterine over 9 nM/l, the mean level of beta 2-microglobulin constituted 3.33 +/- 0.32 mg/l and in patients with the normal concentration of neopterine, it amounted to 1.91 +/- 0.18 mg/l. The growth of the concentration of beta 2-microglobulin in the groups of patients under comparison was seen in 79 and 14% of cases, respectively. It is concluded that neopterine measurements are advisable in the laboratory diagnosis of myocarditis in DCMP patients. Potential mechanisms of the rise of neopterine formation are discussed from the standpoint of hyperinterferonemia.

Adolescent

[The ECG in dilated cardiomyopathy with different degrees of the manifestation of cardiosclerosis].

ECG of 46 patients who had died from dilated cardiomyopathy were retrospectively examined in order to evaluate characteristic ECG changes in relation to myocardial sclerotic severity according to autopsy findings. It was found that 1) one of ECG features in this disease is QRS complex morphology in left chest leads in the form of "rS", "RS" as being independent of cardiosclerotic severity. The deep wave S V5-V6 was due not only to rotation shifts during left ventricular hypertrophy (dilatation), which was typical of dilated cardiomyopathy right ventricle mass; 2) as cardiosclerosis progresses, the frequency and severity of intraventricular conduction disturbances progressively increase; 3) ectopic arrhythmias and atrioventricular block are not caused only by cardiosclerosis and likely to be induced by drug therapy (cardiac glycosides); 4) despite cardiosclerotic development in patients with dilated cardiomyopathy, ECG retains voltage criteria of enlarged cardiac cavities; 5) enlarged cardiac cavities can be determined by standard 12 ECG leads in 73.9% of cases.

Adolescent

[The characteristics of cardiosclerosis in dilated cardiomyopathy].

In 52 patients who had died of dilated cardiomyopathy (DCMP) severity of cardiosclerosis (CS) was studied in relation to the patients' age, possible etiological factors, disease duration, and heart weight. In DCMP, diffuse and diffuse small focal CS were common in all segments of the heart, including myocardial portions without macroscopically visible changes. Various types of CS in DCMP were seen in the left ventricular (92.3% cases), ventricular septum (86.5%) and right ventricle (68.2%). There are highly significant variations in the degree of CS in various patients with DC, however, different parts of the heart showed similar changes within the observation. No direct relationship was found between the cardiac weight and severity of CS. Diffuse CS prevailed in cases of DCMP with infective onset of disease. There was a direct relationship between the CS severity and disease duration in DCMP patients.

Adolescent