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Biomedical subjects

V N Orekhovich

Publications and source records attributed to V N Orekhovich.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

[A new approach to the problem of cardio-vascular regulation: the endocrine function of the heart (review of the literature)].

Besides generally known functions, the heart has also an endocrine function. Atrial cardiocytes, being typical secretory cells, released peptide hormones into the blood stream: atrial natriuretic peptide containing 28 amino acids and cardiodiolatin. The structure of atrial peptides was determined. It was shown that both derived from their common precursor, a protein containing 151 amino acid. The presence of specific receptors was demonstrated on plasmatic membranes of cells of kidney epithelium, arterial smooth muscle, arterial endothelium, kidney cortex and hypophysis. The interaction of atrial peptides with these receptors activated the guanylate cyclase system. The biological action of atrial peptides manifested itself in the quick, massive and instantaneous increase of diuresis and electrolyte excretion, elevation of clearance of creatinine, decrease of kidney vascular resistance, intensification of glomerular filtration, inhibition of stimulated secretion of aldosterone, relaxation of blood vessels, elimination of arterial and intestinal spasm induced by various endogenous and exogenous vasoconstrictors and correction of kidney hypertension. Various radioimmunoassays for detection of atrial peptides in human blood plasma were developed; it was shown that in patients with congestive failure the atrial peptide content was increased.

Animals↗
PubMedDate not supplied

[The role of lysosomal proteinases in tissue destruction].

Action of lysosomal and other proteolytic enzymes on components of the intracellular matrix--collagen, proteoglycans and fibronectin are reviewed. Various types of extra- and intracellular degradation of the intracellular matrix and interrelationship of these types are discussed. Regulatory functions of lysosomal proteinases and their role in activation of latent collagenase and in inactivation of alpha 1-proteinase inhibitor are considered. Some physiological and pathological processes involving local destruction of tissues are discussed.

Animals↗
PubMedDate not supplied

[Characteristics of cysteine peptidohydrolases from the human kidney cortex].

Spectrum of cysteine peptide hydrolases was studied in human kidney cortex using a variety of protein and synthetic substrates after the preparation was fractionated on Sephadex G-100 following the precipitation with ammonium sulfate 40-70%. Activities of dipeptidyl aminopeptidase I, lysosomal carboxypeptidases A and B, cathepsins B and H, as well as the activity of Ca+2-dependent neutral proteinase were detected. A thiol-dependent proteolytic activity, which was apparently stimulated by cathepsin T- and -M like enzymes, was also observed. Besides, the proteinase with molecular mass of 50-60 KDa and high hemoglobin and casein splitting activity was found. This activity cannot be attributed to any of the proteinases so far known. Isoelectrofocusing technique showed that two forms of cathepsin B occurred in human kidney with isoelectric points at pH 5.32 and pH 5.65; two forms of cathepsin H were also detected exhibiting isoelectric points at pH 6.03 and pH 6.7.

Chromatography, Gel↗
PubMedDate not supplied

[Fluorometric method of determining prolylendopeptidase activity in human erythrocytes in normal and pathologic conditions].

A highly sensitive fluorometric method for determination of prolylendopeptidase (PE) activity in human erythrocyte hemolysates in the presence of hemoglobin has been developed. The method is based on measurement of fluorescence of 4-methyl-7-aminocoumarine released in the course of enzymatic reaction from the substrate Z-glycyl-proline-4-methylcoumarine-7-amide. A correlation was introduced for the quenching of fluorescence by hemoglobin. The method is suitable for the determination of PE activity in human erythrocyte hemolysates in various pathological states. The dependence of PE activity on the incubation time, protein and substrate concentrations were studied using the 1,200-fold purified preparations of prolylendopeptidase II. The values of PE activity in erythrocyte hemolysates of healthy donors and in those of patients with odontogenic phlegmons of maxillary-facial area were virtually identical. PE activity in erythrocyte hemolysates of stored blood was 5 times lower than that in the cell hydrolysates of fresh blood. The PE activity was not observed in blood serum of fresh and stored blood of healthy persons and of patients with acute inflammatory processes of maxillary-facial area, as well as in blood serum of patients with hepatitis and glomerulopephritis.

Acute Disease↗