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Biomedical subjects

O M Panasenko

Publications and source records attributed to O M Panasenko.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Low-density lipoproteins with different capacity for aggregation].

Preparations of low-density lipoproteins from healthy donor blood contain lipoprotein particles with different capacity for aggregation: upon stirring, some particles form aggregates significantly more quick than others. After stirring, lipoprotein particles are separated by ultracentrifugation into two fractions: a fraction of large aggregates and a fraction of small particles without intermediate forms. It is known that lipoprotein aggregates can accelerate intracellular accumulation of lipids. Therefore, it is supposed that particles of high aggregation ability are more atherogenic.

Centrifugation, Density Gradient↗
PubMedDate not supplied

[A comparative study of the lipid phase in native and circulating multiple-modified low-density lipoproteins of human blood by the use of the spin probe method].

Different approaches based on the spin probe method were used to compare the physical state of the surface lipid monolayer in subfractions of low-density lipoproteins: in native low-density lipoproteins constituting the bulk of human blood low-density lipoproteins and in circulating multiple-modified low-density lipoproteins whose portion is minor in healthy persons but significantly increases in atherosclerotic patients. The data obtained in in vitro experiments suggest that circulating multiple-modified low-density lipoproteins possess atherogenic properties. The order parameter S, rotational correlation time tau, and hydrophobicity parameter h were calculated from electron spin resonance spectra of a series of spin probes whose paramagnetic groups are located at different depths of the lipid monolayer. These parameters characterize the molecular packing, fluidity, and polarity in the microenvironment of paramagnetic groups. The kinetics of the reduction of paramagnetic groups by ascorbate and oxidation by hypochlorite were obtained for the spin probe whose paramagnetic group is located deeply in the lipid monolayer at the level of the terminal segments of phospholipid acyl chains. No difference between native low-density lipoproteins and circulating multiple-modified low-density lipoproteins was revealed in respect of the physical properties of the lipid domain of surface proteolipid layer, as sampled by spin probes.

Arteriosclerosis↗
PubMedDate not supplied

[Spin label study of structural changes at different depths of phospholipid membranes after their peroxidation].

Changes of structural organization of liposomal phospholipid membranes, after their Fe2+-induced peroxidation were studied at different depth using nitroxyl derivatives of stearic acid. It was established that during Fe2+-induced lipid peroxidation a strong rise in lipid polarity accompanied with immobilization of acyl chains of phospholipids at the depth of 0.6-0.8 nm from the surface was measured. At the same time no significant changes in the structural organization were seen at the depth of 20-22 nm.

Electron Spin Resonance Spectroscopy↗
PubMedDate not supplied

[Determination of the surface charge of lipoproteins and its changes during lipid peroxidation].

Surface potential of human plasma lipoproteins was studied by the use of positively charged spin probe. The calculated values of surface potential of high and low density lipoproteins appeared to be -29 +/- 1 and -16 +/- 1 respectively. It was shown that lipid peroxidation process induces an increase of surface potential of both high and low density lipoproteins. Probably, it is connected with the increase of the negative charge density on their surface. This fact can play an important role in pathogenesis of diseases with lipid metabolism and lipid peroxidation level disorders in plasma (atherosclerosis, ischemic heart disease etc.).

Electricity↗
PubMedDate not supplied

[Effect of thyroid hormones on the physico-chemical properties of lipids in the liver mitochondria of rats].

The administration of thyroxine to rats (300 micrograms per 100 g of body mass intraperitoneally) resulted in a decrease in the content of cardiolipin, cholesterol and an increase in lysophosphatidylethanolamine in rat mitochondria as compared to normal in 48 hours. During the registration of spin-labeled mitochondrial lipids using the EPR method thyroid-related changes in the regulation parameter on Arrenius' charts were detected suggesting the regulation of the physical state of mitochondrial lipids by thyroid hormones. It was assumed that the observed hormone-related modifications of the physicochemical state of mitochondrial lipids illustrated the membranotropic mechanism of the regulation of mitochondrial functions by thyroid hormones.

Animals↗
PubMedDate not supplied

[Effect of thyroid hormones on heat-induced changes in the EPR-spectra of erythrocytes].

An increase in the fluidity of membranes in experimental hyperthyreosis of rats was shown by the registration of EPR-signals labeled with spin probe (5-dosilsterate). Modifications of the physical state of erythrocytic membranes induced in vivo by thyroid hormones were shown to depend on the fatty acid composition of food fats. Thus, the simulation of hyperthyreosis against a background of a diet with more viscous fats (pork lard) was accompanied by a decrease in the fluidity of erythrocytic membranes, whereas food enrichment with polyunsaturated fats (sunflower oil) inhibited the effect of hyperthyreosis on the structural state of membranes. An increase in the fluidity of membranes also resulted from the incubation of erythrocytes of normal animals with physiological concentrations of triiodothyronine (10(-9) M). Under these conditions adding up of thyroxine (10(-7) M) prevented the effect of the first hormone on the structure of membranes. It was assumed that a modifying effect of thyroid hormones in vivo was partially based on rearrangements in the fatty acid composition of membrane lipids.

Animals↗
PubMedDate not supplied

[The effect of hypochlorite on electrical surface properties of human blood lipoproteins].

Surface potential of human blood lipoproteins was studied by the use of Mn(2+)-ions as a positively charged spin probe. The calculated values of surface potential of low density lipoproteins (LDL) appeared to be -17.7 +/- 1.2 mV. It was shown that hypochlorite (OCl-) induced an increase of negative surface potential of LDL. Agarose gel electrophoresis was used for the comparative analysis of electrophoretic mobility of human blood lipoproteins of different classes. It was shown that the interaction of hypochlorite with lipoproteins caused the partial degradation of lipoproteins and the increase in surface charge. High density lipoproteins appeared to be more resistant to the action of OCl- than LDL and especially very low density lipoproteins.

Electricity↗
PubMedDate not supplied

[Correction of lipoprotein lipid peroxidation in experimental atherosclerosis with polyunsaturated fatty acids combined with antioxidants].

Atherosclerotic lesion of the aorta and lipid peroxidation (LPO) in blood and in lipoproteins produced in hepatocytes were studied in rabbits with experimental atherosclerosis maintained on a diet enriched in polyunsaturated fatty acids containing in corn oil (2 ml/kg daily during 30 days) and antioxidants alpha-tocopherol and carnosine (2.5 mg/kg and 50 mg/kg, respectively, daily during 30 days). This diet exhibited a hypocholesterolemic effect accompanied by approximately a 10-fold decrease of the impaired aortic area, as well as lowered content of 2-thiobarbituric acid-positive LPO products occurring in blood and, especially, in apoB lipoproteins. The antioxidant-containing diet decreased distinctly the content of LPO products both in the liver tissue homogenate and lipoprotein fraction (d < 1.065 g/cm3) produced by hepatocytes during 30-min perfusion of liver tissue. The findings suggest that the diet enriched in polyunsaturated fatty acids and antioxidants contributed to a decrease of LPO products content in the blood serum and apoB lipoproteins as well as to the inhibition of lipoprotein oxidation during their synthesis in liver cells; the diet may be recommended for the prophylaxis and treatment of atherosclerosis.

Animals↗
PubMedDate not supplied

[Comparative study of the kinetics of phospholipid liposome peroxidation, induced by hypochlorite and in the Fe2+ + ascorbate system].

The present study examined the kinetics of accumulation of lipid peroxidation products in phosphatidylcholine liposomes incubated with hypochlorite (HOCl/OCl-) or with FeSO4 in the presence of ascorbate. The incubation of liposomes with HOCl/OCl- led to the accumulation of primary (lipid hydroperoxides and conjugated dienes) and secondary (TBA-reactive substances) lipid peroxidation products identical to those generated in the presence of Fe2+/ascorbate. However the rate of the formation of lipid peroxidation products as well as the gain in their amount were sufficiently higher (4-150-fold and 3-6-fold, respectively) in the case of HOCl/OCl(-)-induced lipid peroxidation as compared to lipid peroxidation in the Fe2+/ascorbate system. The accumulation of lipid peroxidation products lasted until HOCl/OCl- was present in the reaction mixture. The data obtained support our hypothesis that hypochlorite produced by activated neutrophils and monocyte/macrophages may be reasonable for the initiation of lipid peroxidation in blood.

Animals↗
PubMedDate not supplied

[Effect of hypochlorite and hydrogen peroxide on the ability of hemoglobin to stimulate lipid peroxidation of low density lipoproteins].

The ability of hemoglobin, modified by H2O2 or HOCl/OCl-, to induce lipid peroxidation (LPO) in low density lipoproteins (LDL) was studied, as well as the effects of haptoglobin. It was found that Hb modification by H2O2 or HOCl/OCl- increased generation of TBA-reactive substances in low density lipoproteins. Modified Hb was as double or more reactive compared to intact Hb. Free radical scavengers (ethanol and mannitol) gave no effect on LPO in LDL. On the other hand, ferric iron chelator desferrioxamine decreased LPO 5-6 times. Ferrous iron chelator- o-phenanthroline was effective only in the case of LPO, induced by H2O2 modified Hb. Haptoglobin (plasma protein forming complexes with Hb) decreased LPO induced by both intact or HOCl/OCl modified Hb. The results of the paper show that modification of Hb by H2O2 or HOCl/OCl- increase the ability of Hb to induce LPO in LDL, probably due to metHb, ferrylHb or free iron production.

Free Radical Scavengers↗