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O A Azizova

Publications and source records attributed to O A Azizova.

131 records · Page 8Linked to original sources
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↗
PubMedDate not supplied

[Role of lipoprotein bound copper ions in lipid peroxidation of low and high density lipoproteins].

Copper-catalyzed lipid peroxidation (LPO) in low density lipoprotein (LDL) and two subfractions of high density lipoprotein (HDL2 and HDL3) isolated from human serum was studied. The levels of LPO were estimated as thiobarbituric acid-reactive substances (TBARS). The amount of TBARS increased in a time-dependent manner when either LDL, HDL2 or HDL3 (0.4-1.2 mg protein/ml) was incubated at 37 degrees C during 4 h with phosphate-buffered saline containing CuSO4 (2-80 microM). The increase in CuSO4 concentration to some value therewith caused the enhancement of the rate of TBARS formation but the following increase in CuSO4 concentration beyond that value didn't already affect the kinetics of LPO in lipoproteins. It was also shown that the lesser was the concentration of lipoprotein the lesser CuSO4 concentration was needed to reach maximal rate of TBARS formation. The data obtained point to the versatility of the mechanism of copper-catalyzed oxidation of low and high density lipoproteins and suggest that the decisive role in the process belongs to copper ions bound to lipoprotein particle.

Copper↗
PubMedDate not supplied

[Effect of metal cations on the copper induced peroxidation of the low density lipoproteins].

The effect of metal cations on copper-catalyzed lipid peroxidation (LPO) of low density lipoproteins (LDL) was examined. The presence of metal cations in the incubation media containing LDL (0.8 mg protein/ml) and CuSO4 (0-80 microM) influenced on LPO of LDL as evident by the measurement of TBARS. With the concentrations of CuSO4 less than 10 microM, the metal cations caused an increase in LDL peroxidation. Zn2+ appeared to be the most effective inductor, Mn2+ was less effective, and the influence of Ca2+ and Mg2+ was insignificant. With greater CuSO4 concentrations Mg2+ showed no effect on TBARS formation in LDL while the addition of other nontransition metal cations to the incubation mixture led to the inhibition of LDL peroxidation. The capacity for inhibition decreased in the row Mn2+ > Zn2+ > Ca2+ > Mg2+. The possible mechanism explaining these results may be in the competition of metal ions for copper binding sites on LDL. Our results allow to suggest the existence of two types of copper binding sites on LDL, tight-binding sites which are non-effective in LPO and effective weak-binding sites.

Binding Sites↗
PubMedDate not supplied

[The effect of oxidized low density lipoproteins on ADP-induced platelet aggregation in plasma].

The investigation of the effect of oxidized lipoproteins on platelet activity is important for the understanding of the plague formation under atherosclerosis. In the present work, we examined the influence of low density lipoproteins (LDL) on ADP-induced platelet aggregation in the platelet rich plasma. In was demonstrated that mixing of plasma and LDL was accompanied by the decrease of ADP-induced aggregation parameters as compared to control (mixing with buffer). After 1 h incubation, platelet ADP-aggregation in the sample containing oxidized LDL (oxLDL) exceeded the ADP-aggregation in the control sample. The dependence of the aggregation parameters on the incubation time and on the degree of LDL oxidation were obtained. No difference in the cholesterol and phospholipid content was observed between cells incubated with buffer, native or oxidized LDL. Therefore, the possible oxLDL-induced accumulation of cholesterol in platelet membranes is excluded as a reason for the increased cell aggregation.

Adenosine Diphosphate↗