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Biomedical subjects

A G Tonevitskiĭ

Publications and source records attributed to A G Tonevitskiĭ.

At least 19 recordsLinked to original sources
PubMed2006

[Spectral parameters of heart rate variability and frequency of detection of autoantibodies to beta(1)-adrenoreceptors in patients with tachyarrhythmias: idiopathic and at the background of primary myocardial diseases].

In order to assess parameters of heart rate variability (HRV) and prevalence of autoantibodies against the beta(1)-adrenoreceptors in patients with cardiac arrhythmias we studied 42 patients with arrhythmias and 20 healthy control subjects. Thirty one patients with idiopathic arrhythmias were included in group I: with paroxysmal atrial fibrillation or flutter (n=13), paroxysmal atrial tachycardia (n=2) and paroxysmal ventricular tachycardia (n=16). Group II was formed of 11 patients with paroxysmal ventricular tachycardia and dilated cardiomyopathy or chronic myocarditis. ab1-AR were determined in blood serum by direct immunoassay. Synthetic fragment containing 26 amino acids of ab1-AR second loop was used as antigen. Groups I (54.8%) and II (63.6%) showed similar prevalence of ab1-AR, which was significantly higher than in control subjects (10%) (p<0.005). HRV parameters in I group were lower in ab1-AR-positive compared with ab1-AR-negative patients. At the same time HRV parameters in ab1-AR-positive patients were significantly different from those in controls (p<0.05). In group II HRV parameters of ab1-AR-positive and ab1-AR-negative patients were significantly lower than in control subjects (p<0.05). We suppose, that ab1-AR could participate in dysfunction of chronotropic heart regulation and contribute to development of arrhythmias in patients with structurally normal hearts.

Adult↗
PubMed2006

[The role of anti-beta1-adrenergic receptor autoantibodies in development of heart failure].

Epitopic analysis of anti-beta1-adrenergic receptor autoantibodies in the serum of patients with cardiomyopathy was performed. An immunoenzyme test system for detection of autoantibodies was developed using peptide containing 26 amino acids of the second extracellular loop of the beta1-adrenergic receptor as antigen. It was demonstrated that removal of autoantibodies against beta1-adrenergic receptor in patients with cardiomyopathy by immunoadsorption and plasmapheresis metodes led to improvement of the heart pumping capacity.

Amino Acid Sequence↗
PubMed2006

[C-reactive protein level and rate of detection of autoantibodies to beta(1)-adrenoreceptors in patients with supraventricular tachyarrhythmias].

In order to assess concentration of C-reactive protein (CRP) and prevalence of autoantibodies against beta(1)-adrenoreceptors (abeta(1)-AR) in patients with cardiac supraventricular arrhythmias we studied 53 patients with arrhythmias and 20 healthy control subjects. Patients with idiopathic arrhythmias (atrial fibrillation or flutter and atrial tachycardia, n=35) comprised group I. Group II was formed of 15 patients with supraventricular arrhythmias and dilated cardiomyopathy (DCM) or chronic myocarditis. Patients of group III (n=23) had supraventricular arrhythmias and arterial hypertension (AH). CRP concentration was determined by recently developed well standardized high sensitivity method. abeta(1)-AR were detected in blood serum by direct immunoassay. Synthetic fragment containing 26 amino acids of abeta(1)-AR second loop was used as antigen. Patients with supraventricular arrhythmias and DCM or chronic myocarditis had higher median CRP (8.0 mg/1) than patients with idiopathic arrhythmias (0.78 mg/l), with supraventricular arrhythmias and AH (1.57 mg/l), or control group (0.6 mg/l). Groups I, II and III showed similar prevalence of ab1-AR (51.4, 40.0, 52.2%, respectively), that was significantly higher than in control subjects (10%) (p<0.005). These results provide evidence of the possible presence of autoimmune and/or inflammatory processes that may be involved in the genesis of supraventricular arrhythmias.

Adult↗
PubMed2002

[Prevalence of detection of autoantibodies to beta-1 adrenoreceptors in patients with myocarditides and cardiomyopathies].

BACKGROUND: Autoantibodies to the second extracellular loop of a cardiac beta1-adrenoreceptors has been detected in some patients with cardiomyopathies and myocarditides. In animal experiments these autoantibodies have been shown to cause reduction of myocardial contractility. AIM: To estimate prevalence of detection of autoantibodies to beta1-adrenoreceptors in patients with myocarditides and cardiomyopathies. MATERIAL: Forty three patients including 18 with dilated cardiomyopathy (DCM), 14 with ischemic heart disease (IHD), 3 with myocarditides, 1 with alcoholic cardiomyopathy and 7 after cardiac transplantation. METHOD: Autoantibodies to beta1-adrenoreceptor were determined in patient's blood serum by direct immunoassay. Synthetic fragment containing 26 amino acids of the beta1-adrenoreceptor second loop was used as antigen. RESULTS: Ten patients had obviously elevated content of autoantibodies. Three of these patients had IHD, 3 - DCM, 1 was studied 6 moths after myocarditis and 3 - 6-9 years after cardiac transplantation. Tests were repeated with intervals from 6 months to 1 year and levels of autoantibodies remained elevated in all these patients. Detection of antibodies did not depend on the etiology of systolic cardiac failure (IHD, DCM), severity of hemodynamic impairment, presence of disorders of cardiac rhythm or conduction.

Autoantibodies↗
PubMed1991

[Monoclonal antibodies to human small-cell lung cancer].

Murine monoclonal antibodies to human small cell lung cancer (SCLC) have been developed and partially characterized. Primary hybridoma clones were screened in the indirect immunofluorescence assay (IFA) on alive H417 cells. Then five clones (IgG1, IgG2a, IgG3 and IgM) non-reactive with normal human bone marrow cells and positively reactive with SCLC tumors were selected. The H417.3 antibody is directed against 47-50kD surface antigens of H417 cells. The antibodies are supposed to be applied for the immunodetection of SCLC metastases to bone marrow and immunotoxin preparations.

Animals↗
PubMed1990

[Study of dipeptidyl peptidase IV as a surface marker of human natural killer cells].

The enriched populations of natural killer (NK) cells have been obtained using two different approaches. The first one was based on the separation in a density gradient of Percoll and further formation of rosettes with sheep erythrocytes. This method allowed to isolate the population containing approximately 70% of CD16(+)-cells. The second approach consisted in separating lymphocytes on a flow cytofluorometer FACS II. Using this method the population with 80% CD16(+)-cells was isolated from PBMC. Studies on morphological, phenotypical and functional characteristics of the first population revealed that NK cells constituted 70% of total number of cells; T-lymphocytes, 8-lymphocytes and monocytes constituted the minor population (10%, 8% and 1% respectively). Activity of DPIV was determined on both cell populations obtained. As it was shown, approximately 27% of the cells isolated using percoll density gradient and 22% of the cells after the separation on a flow cytofluorometer carried the enzyme molecules on the cell surface. The results of the present study apparently indicate that part of NK cells (about 10%) is characterised by the presence of DPIV on the cell surface.

Cell Separation↗
PubMed1990

[Isolation of desialylated low density lipoproteins from the blood of patients with ischemic heart disease by affinity chromatography].

The attempt was performed to isolate desialylated low density lipoproteins (LDL) from the blood of healthy subjects and patients with coronary heart disease by affinity chromatography with immobilized agglutinin of Ricinus communis, a lectin that interacts specifically with galactose residues. A part of LDL was bound to sorbent and could be replaced by galactose but not other saccharide constituents of the LDL molecule. Bound LDL subfraction had a 2-3-fold lower content of desialylated LDL in CAD patients was about 3-fold higher than in healthy subjects. Desialylated LDL induced a 2- to 4-fold increase of total cholesterol content in cultured human aortic intimal cells, whereas unbound LDL had no effect on intracellular cholesterol level. It is assumed that the subfraction of desialylated LDL may be responsible for the atherogenic properties of LDL in CAD patients.

Adult↗
PubMed1990

[Biotinylated pH-sensitive liposomes--containers for guided administration of biologically active substances to the cells].

The technique is described for obtaining pH-sensitive biotinylated liposomes. The liposomes included phosphatidyl ethanolamine, oleic acid, cholesterol, biotin amidocaproyl phosphatidyl ethanolamine, with a molar ratio of 7:3:3:0.1 or 4:2:4:0.1. The fluorescein stain calcein at ++self-limited concentration, 32-P-dTTP, or DNA was incorporated into the internal liposome medium. The liposomes were stable in neutral or mildly alkaline medium but became leaky and showed agglutination at pH 5.7. Liposomes were agglutinated in the presence of avidin and bound specifically to the layer of avidin on the surface of immunological plates. The apparent liposome affinity to the avidin layer was up to 10(-11) M. The avidin-biotin system allows for specific binding of liposomes to human lymphocytes via biotinylated anti-CD5-antibodies. A simple, convenient, and rapid procedure has been elaborated for the binding of water-soluble substances (plasmid DNA included) to liposomes without DNA destruction.

Avidin↗