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Biomedical subjects

E A Gorbatenkova

Publications and source records attributed to E A Gorbatenkova.

13 recordsLinked to original sources
PubMed2000

Hypochlorous acid and human blood low density lipoproteins modified by hypochlorous acid increase erythrocyte adhesion to endothelial cells.

The ability of hypochlorous acid (HOCl) (anion form - hypochlorite, OCl-) and HOCl/OCl- -modified human blood low density lipoproteins (HOCl-LDLs) to stimulate erythrocyte adhesion to endothelial cell monolayers was studied. LDLs were modified by incubating at different HOCl/OC- concentrations. This led to a damage of proteins and lipids. We found (1) a more than 20-fold decrease of LDL fluorescence intensity (extinction at 285 nm, emission at 340 nm), (2) accumulation of secondary (TBA-reactive substances) and final (Schiff bases) products of lipid peroxidation, and (3) increase in the electrophoretic mobility of LDLs. Preincubation of endothelial cells (ECs) with HOCI/OCl- (up to 50 microM) enhanced erythrocyte adhesion to the EC monolayer. Preincubation of ECs with HOCl-LDLs (up to 250 microM of HOCI//OCl- during LDL modification) (1) caused an increase in the cholesterol/phospholipid molar ratio in EC and (2) enhanced adhesion of erythrocytes to endothelium. Application of HOCl/OCl- at concentrations above 50 microM or treatment of LDLs with 500 microM HOCl resulted in the cytotoxic effect on ECs and led to a decrease in the molar cholesterol/phospholipid ratio in ECs and adhesion of erythrocytes to endothelium. The results suggest that HOCl/OCl- at physiological concentrations stimulates the adhesion of blood cells to the endothelium and cholesterol accumulation in the vessel wall ECs either directly or due to LDL modification. Both effects could be important in the development of many vascular diseases.

Arteriosclerosis↗
PubMed1989

[The red light of the helium-neon laser reactivates superoxide dismutase].

The effect of low-energy helium-neon laser (HNL) on enzymatic activity, absorbtion spectra and electron paramagnetic resonance (EPR) signals of superoxide dismutase (SOD) from bovine erythrocytes in acid medium were investigated. It was found that incubation during 2 hours at pH 5.9 led to eventually complete inactivation of the enzyme. The subsequent illumination of inactivated SOD by HNL brought about the enzyme reactivation. Both absorption and EPR-spectra were changed after incubation at pH 5.9. These changes may be attributed to protonation of histidine residue in the enzyme active site. After laser irradiation both absorption and EPR spectra were restored to those typical of native enzyme at pH 8.2. In a model system, copper-histidine complex, absorption maximum was shifted from 632-633 nm at pH 5.8 to 639-640 nm at pH 8.5-9.0. The similar long-wave length shift of the maximum was observed after illumination by HNL at pH 5.8. It may be postulated that the photoreactivation of SOD consists essentially in deprotonation of His-61 residue in the enzyme active site and subsequent recovery of imidazole bridge between copper and zinc which had been destroyed at low pH. Since many other enzymes possess similar copper-histidine structures in their active sites, one may expect diverse effects of red (laser) light on the enzyme activity.

Animals↗
PubMed1989

[Physicochemical and functional properties of the peripheral blood lymphocytes in ischemic heart disease].

Electron spin resonance techniques was used for the investigation of the structural organization of lymphocyte plasma membranes of healthy donors and IHD patients. We found the increased fluidity of peripheral blood lymphocyte membranes of patients with IHD using 5 doxyl stearic acid spin label. The ordering of the membrane lipids increased proportionally to the increase of cholesterol cell content. This is the important reason for the inhibition of mitogenic cell activity during IHD. Measured by the chlortetracycline-fluorescence alterations in the processes of mitogen-induced Ca+2 redistribution might be one of the mechanisms which mediates the influence of membrane structure changes on the lymphocyte functions.

Calcium↗
PubMed1989

[Secondary atherosclerotic immunodeficiency].

A study of peripheral and central mechanisms of secondary immunodeficiency in atherosclerotic patients demonstrated altered structural layout of lymphocyte membranes due to cholesterol accumulation in the cells. This was associated with increased membrane viscosity, suppressed mitotic activity and lower cap formation rate as well as changed intracellular calcium redistribution. Thymic ischemia due to occlusion or stenosis of thymus-supplying vessels was shown to promote age-related transformation of thymic tissue. Experimental simulation of thymic ischemia resulted in an abrupt drop of serum thymic factor in the blood of animals and the development of an immunodeficient condition.

Animals↗
PubMed1988

Photoreactivation of superoxide dismutase by intensive red (laser) light.

The effects of helium-neon laser (HNL) on activity, absorption spectra, and ESR signals of superoxide dismutase (SOD; E Cul.15.1.1) from bovine erythrocytes in acid medium were investigated. It was found that incubation during 2 hours at pH 5.9 led to inactivation of the enzyme. The subsequent illumination of SOD by HNL brought about the enzyme reactivation. Both absorption and ESR spectra were changed after incubation at pH 5.9 and restored after laser irradiation. In a model system, copper-histidine complex, absorption maximum was shifted from 632-633 nm at pH 5.8 to 639-640 nm at pH 8.5-9.0. The similar shift of the maximum was observed after illumination by HNL at pH 5.8. It may be postulated that the photoreactivation of SOD consists essentially in deprotonation of His-61 residue in the enzyme active site and subsequent recovery of imidasol bridge between copper and zinc which had been destroyed at low pH. Since many other enzymes possess similar histidine-copper structures in their active sites, one may expect diverse effects of red (laser) light on the enzyme activity. Heme-containing enzyme, catalase was also found to be photoreactivated by HNL after inactivation at pH 6.0.

Animals↗
PubMed1986

[Role of the cholesterol of platelet membranes in disorders of their structuro-functional condition in angina pectoris patients].

A study of 80 anginal patients showed their platelet molar cholesterol/phospholipid ratios, platelet membrane microviscosity, membrane release of calcium and fatty acids, and platelet aggregation capacity to be elevated. It is assumed that excessive platelet cholesterol has a significant effect on platelet aggregation, that is mediated by the intraplatelet processes examined, in anginal patients.

Adult↗
PubMed1984

[Structural and functional properties of the thrombocytes in ischemic heart disease].

Electronic paramagnetic resonance was used to study the structural and functional properties of platelets from patients with coronary heart disease. It was established with the use of the spin probe 5-doxylstearate that cytoplasmic platelet membranes of coronary heart disease patients are marked by a higher molecular packing as compared to normal. The rate of platelet aggregation studied independently of plasma factors appeared also higher, with a direct correlation being discovered between the aggregation properties and viscosity of platelet membranes. Such a modification of the physical and functional properties might be accounted for by cholesterol accumulation which is evidenced by an increase in the molar content of cholesterol in the cells. It is suggested that platelets from coronary heart disease patients, which have more rigid membranes, have a greater ability to adhere to other, particularly to endothelial cells, thereby giving rise to the atherosclerosis of the vascular wall.

Adult↗
PubMed1984

[Structural and functional changes in thrombocytes in experimental atherosclerosis].

Electron paramagnetic resonance with the use of stearic acid derivatives (5- and 16-doxylstearate) as spin probes was applied to studies of the structural organization of rabbit platelets in experimental atherosclerosis. Substantial differences were established in the molecular packing of phospholipid plasma membranes, associated with a higher molar content of cholesterol in the cells. An increase in the aggregation properties of platelets was also observed, manifesting in a shorter time of the ADP-induced aggregation of platelets isolated from plasma. The data obtained confirm the primary part of membranotropic cholesterol activity in atherosclerosis, attesting to the validity of the "membraneous" hypothesis of the atherogenesis.

Animals↗
PubMedDate not supplied

[Cholesterol-acceptor properties of high-density lipoproteins with respect to erythrocyte membranes in patients with ischemic heart disease].

A capacity of high density lipoproteins (HDL), isolated from blood of patients with ischemic heart disease, to accept cholesterol of erythrocyte membranes was studied by means of monitoring, using spectra of electron paramagnetic resonance, a disease in the correlation period of rotation, in the patterns of regularity of stearic acid nitroxyl derivatives introduced into the membranes and by a decrease in the molar ratio "cholesterol/phospholipids" in erythrocytes. HDL2 and HDL3, isolated from blood plasma of the patients, were shown to bind cholesterol less effectively after incubation with erythrocytes as compared with the corresponding lipoproteins from blood plasma of healthy persons. Relationship between the phenomenon observed and the physico-chemical properties of HDL in ischemic heart disease are discussed.

Cholesterol↗
PubMedDate not supplied

[Incorporation and release of cholesterol from plasma membranes of hepatocytes and Zajdela hepatoma cells].

Molar ratio of cholesterol/phospholipids was decreased in Zajdela hepatoma cell membranes as compared with rat normal hepatocytes. Microviscosity of lipid bilayer was increased in membranes of normal and malignant cells, while the activity of Na+, K+-ATPase and 5'-nucleotidase was decreased during introduction of cholesterol into the cell membranes. As compared with control groups the duration of life was increased in the group of animals implanted with Zajdela hepatoma cells modified by cholesterol. The data obtained suggest that an increase in microviscosity of membranes in tumoral cells, enriched with cholesterol, might inhibit their mitotic divisions.

5'-Nucleotidase↗
PubMedDate not supplied

[Reactivation of superoxide dismutase by the helium-neon laser irradiation].

When incubating SOD for two hours in the buffer with pH 6.0 practically complete loss of the activity of enzyme was observed at insignificant changes of the absorption spectra in the region of 450 and 680 nm. Irradiation of SOD solution with helium-neon laser resulted in the dose-dependent reduction of spectral and enzymic properties. Similar effect of the red light was also observed when SOD was inactivated with hydrogen peroxide: laser irradiation brought about the reduction of initial absorption spectrum of the enzyme. One can believe that the therapeutic effect of helium-neon laser radiation is conditioned, at least partially, by photochemical reactivation of SOD inactivated under pathological conditions (inflammation, hypoxia) in the tissues.

Enzyme Activation↗
PubMedDate not supplied

[Lipid composition and structure-functional properties of membranes of erythrocytes of different ages].

Age-dependent alterations of plasmatic membranes were studied in rabbit erythrocytes after separation of erythrocytes of various age by means of centrifugation. The membrane structure characteristics were studied using a fluorescent probe pyrene and spin-labelled probes--nitroxyl derivatives of stearic acid and carboline derivatives. Microviscosity of the membrane lipid phase was shown to increase depending on the cell age. Alterations in the membrane structure were accompanied by a decrease in activity of Na-, K+-ATPase. The content and ratio of membrane lipids were altered with an increase in the cell age, which could be one of reasons of the membrane microviscosity elevation. The age-dependent alterations in erythrocyte membranes may be related, firstly, to the mechanism of old erythrocyte elimination from circulation and, secondly, to be the common characteristic for cell ageing, according to the "membrane hypothesis" of ageing.

Animals↗