PubMed Health⌕ Search

Biomedical subjects

O A Azizova

Publications and source records attributed to O A Azizova.

At least 91 records · Page 5Linked to original sources
PubMed1984

[The antioxidant system of transferrin-ceruloplasmin in experimental hypercholesterolemia].

Experimental rabbits were fed cholesterol during three months. The amount of cholesterol, lipid peroxidation products, and the ratio of the ESR signal of ceruloplasmin to one of transferrins (Cp/Tf) increased in the serum of experimental rabbits as compared with the control group animals. The animals with the high Cp/Tf ratio had a low cholesterol level and a low concentration of lipid peroxidation products in the serum. The increased Cp/Tf ratio in the serum may be explained by the elevation of the Cp and Tf antioxidant activity. The rise of the antioxidant activity may be referred to the defence reaction of the body toward hypercholesterolemia.

Animals↗
PubMed1984

[Characteristics of the structural organization of lipoproteins in the blood plasma of patients with ischemic heart disease using the spin probe method].

Structural properties of lipoprotein organization in blood plasma of the patients with ischemic heart disease have been studied by means of electronic paramagnetic resonance method, using a derivate of stearic acid (5-doxylsteararte) as a spin probe. Significant differences in the patterns of thermo-induced structural reorganizations of all the lipoprotein types in normal and pathological states were shown. However, these differences were not found in the lipids isolated from the lipoproteins. In high density lipoproteins HDL2 and HDL3 from blood plasma of the patients with ischemic heart disease a decrease in the micro-environment polarity was shown to take place at the depth of 8 A from the lipoprotein surface. The data obtained suggest the distinct changes in structural organization of all the lipoprotein types in heart ischemic disease, which appear to occur as a result of modification of apoproteins and/or protein-lipid interactions in lipoproteins.

Coronary Disease↗
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↗
PubMed1984

[Thermotropic structural rearrangements in blood plasma lipoproteins in ischemic heart disease].

Structural properties of blood plasma lipoproteins (LP) from coronary heart disease (CHD) patients were examined. Substantial differences were found in the pattern of the heat-induced structural restitution of LP of all classes in health and disease. At the same time no such differences were discovered in lipids isolated from LP. In high density lipoproteins from the plasma of CHD patients, a decrease in the microenvironmental polarity was shown to take place at a depth of 8 A from the surface of LP. The data obtained indicate substantial changes in the structural organization of LP of all classes in CHD. It is assumed that these changes are consequent on the modification of apoproteins and/or protein-lipid interactions in LP.

Coronary Disease↗
PubMed1983

[Spin labels in the analysis of Ca-ATPase in the sarcoplasmic reticulum of rabbit skeletal muscles in hypercholesteremia].

The method of electron paramagnetic resonance with spin-labeled maleimide was used to study variation of the structure of Ca-ATPase of the sarcoplasmic reticulum (SR) in rabbit skeletal muscles under long-term hypercholesterolemia (HC). The rate of the maleimide spin label binding with Ca-ATPase of the SR was decreased in HC, which correlated with a lesser access of spin-labeled thiol groups for potassium ferricyanide and sodium ascorbate. HC led to a considerable reduction in the lability and to enhancement of hydrophobia of the spin-labeled fragment of the enzyme. It is concluded that the disordered function of the SR Ca-pump is a consequence of structural changes in the Ca-ATPase molecule in HC.

Animals↗
PubMed1983

[Modification of an enzymic system for Ca2+ transport in sarcoplasmic reticulum in lipid peroxidation. Change in the molecular organization of the lipoprotein Ca-ATPase complex].

Using ESR spectroscopy of spin probes and spin labelling, the effects of lipid peroxidation (LPO) on the molecular organization of Ca-ATPase from rabbit skeletal muscle sarcoplasmic reticulum membranes were studied. Accumulation of LPO products caused an increase of the hydrophobicity and a decrease of the mobility of the Ca-ATPase polypeptide chain fragment immediately proximal to the enzyme active site. Induction of LPO in the membranes resulted in a decrease of the thermal stability of the lipoprotein Ca-ATPase complex which occurred as a biphasic process. At temperatures of 36-38 degrees C this thermodenaturation consisted in a shift of the Ca-transport ability towards a lower temperature region corresponding to the shift in the low temperature break on the Arrhenius plots for parameter 2A'zz of the maleimide spin label. Within the temperature range of 49-52 degrees C an earlier LPO-induced denaturation determines the low temperature shift of the point for a sharp decrease of the Ca-ATPase activity and of the corresponding break for parameter 2A'zz as well as the dissociation point for the lipoprotein Ca-ATPase complex and the corresponding breaks on the Arrhenius plots for the solubilization parameter, alpha, and the order parameter of spin probes, S.

Animals↗
PubMed1983

[Thermo-induced structural changes in lipoproteins of human plasma, studied with spin probes].

The thermo-induced structural changes in lipoproteins (LP) of human plasma were investigated by the electron paramagnetic resonance method, using 5-doxylstearate as a spin probe. LP were shown to undergo thermotropic transformations at temperatures specific for each LP type. Differences were found in the nature of temperature dependences of the order parameter for the probe localized in LP and for isolated lipids. The denser the LP, the more pronounced the differences. 5-Doxylstearate was shown to be localized not only in the lipid phase of LP, but also in the area of the protein--lipid contact. This indicates that 5-doxylstearate is a useful tool for the study of protein--lipid interactions in pathological processes coupled with their modifications.

Cyclic N-Oxides↗
PubMed1983

[Conformational mobility and enzymatic activity of Ca2+-ATPase from sarcoplasmic reticulum].

Purified preparations of Ca2+-dependent ATPase were lipid-deleted and incorporated into egg lecithin (EL) and dipalmitoyl lecithin (DPL) liposomes. The temperature dependences of the catalytic activity and of molecular mobility of the spin label (N-1-hydroxyl-2,2,6,6-tetramethyl-4-piperidyl) maleimide linked to a highly reactive SH-group in the vicinity of the active center (15-16 A) and of the fatty acid spin probe (6-doxylpalmitate) located in the protein-lipid moiety were compared. The molecular mobility of the spin label was measured by the saturation transfer method; that of the spin probe was estimated from the maximal splitting value. It was found that the catalytic activity of DPL is correlated with the molecular mobility of the hydrophobic part of ATPase, while that of EL with the segment flexibility in the vicinity of the active center.

Animals↗
PubMed1982

[Interaction of spin-labelled phosphatidyl choline with Ca-dependent ATPase from sarcoplasmic reticulum].

The interaction between 3-acyl-2-(6-doxylpalmitoyl) phosphatidyl choline used as a hydrophobic spin probe and Ca2+-dependent ATPase from sarcoplasmic reticulum membranes of rabbit and carp white skeletal muscles was studied. The spin label incorporation into ATPase preparations was performed at initial steps of ATPase isolation by incubating reticulum membranes with the spin probe in the presence of cholic acid. A comparison of the molecular mobility of the probe incorporated into ATPase preparations and into liposomes formed from ATPase phospholipids demonstrated that the presence of the protein in the membrane produces the same effect on the probe mobility as does the decrease of temperature by 10-15 degrees C. The molecular mobility of the probe in the ATPase preparation is increased during protein thermal denaturation. The breaks on the Arrhenius plots for the probe molecular mobility are revealed at the same temperatures (25 degrees for rabbit reticulum and 16 degrees for carp reticulum) as those for the ATPase activity.

Animals↗
PubMed1981

[Interaction between free fatty acids and Ca2+-dependent ATPase from sarcoplasmic reticulum membranes].

The interaction between free fatty acids and Ca2+-dependent ATPase, an intrinsic protein of sarcoplasmic reticulum membranes, was studied with relevance to the changes in membrane permeability induced by free fatty acids. It was found that only unsaturated fatty acids increase the permeability of reticulum membranes for Ca2+, this effect being completely reversible. The increase in the membrane permeability by fatty acids is coupled to a generation of a channel for Ca2+ efflux under effect of Ca2+-dependent ATPase. The interaction between fatty acids and Ca2+-dependent ATPase was demonstrated by the protein fluorescence and electron paramagnetic resonance methods, using spin-labelled fatty acid derivatives. A model demonstrating the increase of sarcoplasmic reticulum membrane permeability for Ca2+ in the presence of the fatty acid-Ca2+-dependent ATPase complex is proposed.

Animals↗
PubMed1980

[Thyroxine: structural transformations in the membranes of rabbit skeletal muscle sarcoplasmic reticulum].

The structure of the membranes of sarcoplasmic reticulum fragments (SRF) normally and in thyrotoxicosis was studied by the spin-label and spin-probe methods and by chemifluorescence. The curves of temperature dependence of the regularity parameter show a typical break for the spin probe at 20 degrees C shifted by 4 degrees C to sower temperatures for thyrotoxins. The same shift was observed with temperature dependence for the correlation period of the spin label covalently bound to the thiol groups of Ca2+ dependent ATPase of sarcoplasmic reticulum. The latent period of thyrotoxins was reduced and the chemifluorescence intensity increased. The results obtained suggest the occurrence of considerable changes in the structure of SRF membranes in thyrotoxicosis.

Animals↗
PubMedDate not supplied

[Letter: Study of the interaction of histones F1, F2b, F2a1, F3 with nucleotides by the method of high resolution nuclear magnetic resonance].

Interaction of nucleotides with histones F-1, F-2b, F-2a1, F-3 have been studied by NMP method. It has been found that the interaction of nucleotides with histones increase in the line F-1. F-2b, F-3, F-2a1. It is suggested that histone F-1 is bound with the nucleotides mainly by electrostatic forces. Bounding of histones F-2a1 and F-3 with nucleotides is due not only to electrostatic sinteractions but also to more specific bonds of the base ring with protein.

Adenosine Diphosphate↗
PubMedDate not supplied

[Binding of divalent cations with low density lipoproteins. A study by ESR].

The binding of bivalent metal ions Cu2+, Zn2+, Ca2+, Mg2+ to low-density lipoproteins (LDL) was investigated by the ESR technique. The monitoring of ESR spectra of paramagnetic Mn2+ ions in the presence of above-listed cations made it possible to evaluate the dissociation constants of their complexes with LDL. The effective dissociation constant of the complex Mn(2+)-LDL used for calculations was KD = (1.1 +/- 0.4) x 10(-4) M according to literature data. The investigated cations may be classified into two groups: 1) low dissociation constants were characteristic for Cu2+ ions [KD = (1.3 +/- 0.5) x 10(-4) M], which demonstrated a high oxidative ability, and for Zn2+ [KD = (0.95 +/- 0.45) x 10(-4) M] and Mn2+ ions, which could strongly influence the copper-induced LDL oxidation; 2) Ca2+ and Mg2+ were characterized by higher values of KD [(6 +/- 1) x 10(-4) M and (7.5 +/- 1.5) x 10(-4) M, accordingly] and slightly affected the Cu(2+)-induced oxidation of LDL. The results of the present work reinforced our earlier conjecture that cations may influence the process of lipid peroxidation, binding only to particular binding sites on the surface of LDL.

Algorithms↗