Biomedical subjects

V F Pozdnev

Publications and source records attributed to V F Pozdnev.

40 records · Page 3Linked to original sources

PubMedDate not supplied

[Correction of cardiac functions in rats with experimental myocardial ischemia by chronic administration of endothelin-converting enzyme inhibitor].

Experiments on chronically instrumented Wistar rats demonstrated that 15 mm microsphere embolization of coronary arteries led to a significant decrease in the systemic (APsyst) and maximal left ventricular systolic pressures (LVSPmax) to 10.1 and 21.1%, respectively (p < 0.05). To evaluate the role of endothelin in this pathology, the inhibitor of endothelin-converting enzyme (ECE), PP-36, was used. PP-36 abolished hemodynamic changes caused by embolization after 4 days per os treatment (starting 2 days before surgical procedure). Dobutamine test revealed marked decrease of LVSPmax and +dP/dtmax responses in the embolized versus sham operated animals. PP-36 normalized ischemical heart response to beta-adrenergic stimulation. Maximal APsyst and LVSPmax increases were observed in embolized rats. PP-36 abolished this effect and led to parallel rising reaction to aminoguanidin in embolized (APsyst: +12.4 +/- 1.6 vs. +6.8 +/- 2.3 mmHg, p < 0.05) as well as in sham operated rats (APsyst: +8.5 +/- 1.1 vs. +5.6 +/- 0.7 mmHg, p < 0.05). Thus, the present research showed the possibility to correct ischemical heart disturbance by using a new ECE inhibitor, PP-36. One possible mechanism of this drugs action may include systemic or myocardial changes in NO contribution to the maintenance of normal arterial pressure.

Administration, Oral↗

PubMedDate not supplied

[Determination of carboxycathepsin (peptidyl dipeptidase) activity in human blood serum].

Based on fluorometric determination of a dipeptide histidil-leucine, which is splitted off from a synthetic substrate (Cbz-Phe-His-Leu) by carboxycathepsin (carboxydipeptidyl peptide hydrolase), a method was developed for estimation of the enzymatic activity in human blood serum. The method is characterized by simplicity and high sensitivity; Use of small amount of blood serum (about 0.03 ml) was possible. In normal human blood serum the carboxycathepsin activity varied from 7.5 to 18 nmoles of the dipeptide, liberated per mg of protein per hr.

Angiotensin-Converting Enzyme Inhibitors↗

PubMedDate not supplied

[The use of various fluorogenic substrates for determining peptide hydrolase activity of the blood serum].

4-methoxy-beta-naphthylamide and 7-amino-4-methyl coumarin, derivatives of Z-Ala-Arg-Arg, Leu- and Gly-Phe-beta-naphthylamides were used as substrates in estimation of peptide hydrolases activity in blood serum of patients with malignant tumors and glomerulonephritis in order to ascertain their efficiency for diagnostic purposes in clinic. Each of the fluorogenic substrates studied was hydrolyzed by various peptide hydrolases from blood serum both under normal and pathological conditions: metallopeptidases, cysteine- and serine-dependent peptide hydrolases. The rate of Z-Ala-Arg-Arg-MNA hydrolysis was decreased in lung, kidney and ileum cancer as well as in glomerulonephritis as compared with normal state. The "alkaline-resistant" cysteine-dependent cathepsin B-like proteinase, hydrolyzing this peptide, was not detected in blood serum neither in normal state nor in these diseases studied. Leu-NA and Gly-Phe-NA were hydrolyzed most effectively in blood serum of patients with lung cancer and glomerulonephritis as compared with normal state; cysteine-dependent peptide hydrolases were most markedly activated. Alterations in the enzymatic activity, detected in blood serum, did not exhibit any specificity for definite diseases, they were observed both in malignant and inflammatory impairments. The data obtained suggest that the fluorogenic substrates studied could not be suitable for clinico-diagnostic purposes.

Clinical Enzyme Tests↗

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↗