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Biomedical subjects

O A Azizova

Publications and source records attributed to O A Azizova.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

[Effect of redox-modified fibrinogen on blood leukocyte functions].

The influence of oxidized fibrinogen on the intensity of luminol-dependent chemilumin escence of blood leukocytes, stimulated by opsonized zymosan was studied. It was shown that the introduction of fibrinogen modified by UV-irradiation in to a suspension of cells resulted in a significant increase in the intensity of the luminol-dependent chemiluminescence of leukocytes. It was suggested that oxidized fibrinogen can influence blood leukocytes, enhancing their functional activity.

Fibrinogen↗
PubMedDate not supplied

[Kinetic characteristics of Cu2+-induced lipid peroxidation in blood plasma and serum].

The aim of this study was to determine the concentration parameters and time-course of copper-induced oxidation in serum and whole blood plasma. We investigated the oxidizability of undiluted and (2-60-fold) diluted whole plasma (prepared with citrate as an anticoagulant) and serum by monitoring the change in the level of conjugated dienes, ketodienes and malondialdehyde in the samples. The kinetic curves of the accumulation of different lipid peroxidation (LPO) products had similar S-shape, but they differed by a number of quantitative parameters--lag-time, time of improvement and the level of maximal rate of oxidation, as well as time of improvement of the maximal accumulation and maximal amount of LPO products. When the LPO products were formed in undiluted plasma and serum, the lag phase of 2-2.5 h for conjugated dienes and ketodienes, and 11-12 h for malondialdehyde was observed. Oxidation profile showed a negligibly short period of inhibition followed by rapid oxidation for all investigated LPO products when plasma and serum were diluted at least 10-fold. The rate of accumulation and amount of LPO products decreased in the following order: conjugated dienes > ketodienes > malondialdehyde. Choice of blood plasma or serum and a dilution factor strongly influenced intensity of copper-induced LPO. Anticoagulant (sodium citrate), that was used by preparation of plasma, possessed an inhibitory action on LPO, due to formation of copper-citrate chelates. Dilution of plasma and serum increased LPO through lowering of influence of water-soluble antioxidants, but action of fat-soluble antioxidants (dissolved in the lipid phase of lipoprotein particles) by was unchanged. These results indicate that measurement of lipid oxidation induced in vitro in the whole plasma or serum might be more relevant model of the lipoprotein oxidation in the blood than the in vitro oxidation of single isolated lipoproteins.

Adult↗
PubMedDate not supplied

[Interrelationship between structural and functional modifications in the membranes of the sarcoplasmic reticulum following lipid peroxidation].

Structural and functional modifications of sarcoplasmic reticulum membranes from skeletal muscles by molecular oxygen was studied. Lipid peroxidation (accumulation of 5-10 nmoles hydroperoxides/mg lipids) results in membrane permeability increase for Ca2+-ions whereas the activity of Ca2+-dependant ATPase preserved unchanged. In the temperature range 5-30 degrees C decrease of solubilization parameter alpha (for nitroxide radical 2,2,6,6-tetramethylpiperidin-1-oxyl) was registered while alpha reached the control values at temperatures higher than 30 degrees C. Further increase in lipoperoxide content (more than 20 nmoles/mg lipids) lead to inhibition of Ca2+dependant ATPase. In this case alpha was lower than in intack membranes in the whole temperature interval investigated. The loss of Ca2+-accumulating capacity is explained on the basis of peroxide clusters formation in lipid bilayer regions of sarcoplasmic membrane. One of the mechanisms of Ca2+-dependant ATPase inhibition after lipid peroxidation is the deficiency of polyunsaturated fatty acyls in microenvironment of the enzyme.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Lipid peroxidation in the blood of patients with suppurative meningitis].

It is shown that the dynamics of lipid peroxidation (LPO) in patients with purulent meningitis is unspecified in character and is encountered both in meningococcal and pneumococcal infection. The level of secondary LPO products and the degree of hyperfermentemia, which are determined according to the dynamics of changes in the activity of aspartate transaminase, are objective characteristics of the severity of the patient's condition and reach maximum on the 5th day of the disease. The correlation between the dynamics of the primary LPO products and the ceruloplasmin/transferin coefficient allows the severity of the disease to be prognosticated.

Adult↗
PubMedDate not supplied

[Formation of iron complexes with ascorbic acid in physiological conditions in vitro and in tissue in vivo].

Rapid dissociated Fe(III)-ascorbic acid complexes are formed after the mixing of Fe(II) (100 mkM) with ascorbic acid (1 mM) at pH-7,4. As a result of these complexes formation Fe(II) concentration was decreased in solution, but o-phenantrolin addition or pH decreased up to 6.1 lead to the destruction of these complexes and reduction of iron up to Fe(II). Iron-ascorbic acid paramagnetic complexes were not observed in the perfused rat liver homogenate. Probably, these facts were due to the presence of other stronger reductants in the tissue.

Animals↗
PubMedDate not supplied

[Free radicals formed during UV-irradiation of unsaturated fatty acids containing peroxidation products].

On the irradiation of oxidized linolic acid an assymetric ESR signal with g-factor 2.0039 and the linewidth 30--33 Oe has been registered. The signal could be the result of photolysis of hydroperoxides. During prolonged irradiation of all the samples accumulation of alkyl radicals characterized by a symmetric signal with a well-defined ultrafine structure has been observed. An increase of the sample temperature up to 87 K in the presence of oxygen was preceded by transformation of alkyl radical R into RO2. All the radicals disappeared at the temperature of 160 K. All these processes seem to be the first phases of photoperoxidation of unsaturated fat acids in lipid-containing systems, including biological membranes.

Electron Spin Resonance Spectroscopy↗
PubMedDate not supplied

[Free radicals formed during UV-irradiation of biological membrane lipids].

Formation of free radicals under UV-irradiation of egg phosphatidyl choline, and synthetic phosphatidyl cholines and their analogs, as well as of their model compounds was studied. When saturated fat lipids are UV-irradiated radicals--CH2CH2 are accumulated at the expense of the breakage of--CH2CH2--COOH-bond. Radicals CH3--OCH2, HCO are formed in aminoalcohols due to the breakage of --OCH2--CH2N+(CH3)3- and--CH2--N+(CH3)3-bonds. It has been found that in natural and synthetic phospholipids radicals are formed in the course of photochemical reactions in complex ether and amine groups. The mechanism of radical formation is discussed.

Amino Alcohols↗
PubMedDate not supplied

Na+/H+ exchange in PAF-stimulated platelets.

In experiments on human platelets, inhibition of Na+/H+ exchange was caused either by equimolar substitution of external Na+ with choline or N-methyl-D-glucamine, by decreasing the pHo to 6.8, or by an inhibitor of the antiport 5-(N-ethyl-N-isopropyl)amiloride (EIPA). In all these cases a considerable inhibition of PAF-induced platelet aggregation and as a rule a more or less marked decrease in the cytoplasmic Ca2+ signal (quin-2-loaded platelets) occurred. Stimulation by 10(-7) M PAF caused biphasic pHi changes in human platelets loaded with the pH-sensitive fluorescent probe BCECF: a small transient decrease, followed by a sustained increase of 0.02 +/- 0.006 pH units, resulted from stimulation of the Na+/H+ exchange. Thrombin (0.1 U/ml) also caused biphasic pHi changes, but the alkalinization step was more pronounced (0.15 +/- 0.03 U). Every means of Na+/H+ exchange inhibition prevented a rise in pHi in stimulated platelets. Activation of the adenylate cyclase system by carbacyclin suppressed the agonist-induced pHi increase. The inhibition of neither cyclooxygenase by 10(-5) M indomethacin nor calmodulin-dependent enzymes by 10(-5) M calmidazolium affected the agonist-induced pHi signals. A decrease in temperature from 37 to 24 degrees C caused a considerable increase in the lag phase of the pHi signal induced by tetradecanoyl phorbol acetate (TPA), but did not affect the kinetics of the pHi signal induced by PAF. An inhibitor of protein kinase C (PKC), compound H-7 (60 microM), completely abolished the TPA-induced increase in pHi but caused only a partial inhibition of the pHi signal in about 50% of the experiments with PAF. On the basis of these results the conclusion is drawn that the activation of PKC is not the only pathway for the PAF-induced stimulation of Na+/H+ exchange. The PAF-induced pHi rise depended both on the presence of extracellular Ca2+ and on the [Ca2+]i increase. On the other hand, inhibition of Na+/H+ exchange decreased the magnitude of the Ca2+i signal in PAF-induced platelets loaded with quin-2, but did not influence the Ca2+ mobilization from intracellular stores as measured by quin-2 or chlortetracycline in experiments with thrombin-stimulated platelets. We conclude that in PAF-activated platelets some initial increase of [Ca2+]i is essential for Na+/H+ exchange activation while activated antiport potentiates a full-scale Ca2+ influx into the cells.

Arachidonic Acids↗
PubMedDate not supplied

[Role of the ceruloplasmin-transferrin system in regulating lipid peroxidation of the blood serum under various regimens of hyperbaric oxygenation].

Rats were treated with oxygen under the pressure of O-4 excessive atmospheres (ati) within 1 hr. Under the pressure of 2 ati content of ceruloplasmin was increased, while concentration of transferrin and content of lipid peroxidation products were decreased in blood serum. The level of ceruloplasmin and transferrin was unaltered, while lipid peroxidation was augmented under the pressure of 3-4 ati. At the same time, in vitro content of these proteins did not alter in blood serum, while concentration of the lipid peroxidation products was increased under the pressure of 2 ati. The system of ceruloplasmin-transferrin appears to be involved in regulation of lipid peroxidation in blood serum under conditions of hyperbaric oxygenation.

Animals↗
PubMedDate not supplied

[Initiation of nonenzymatic lipid peroxidation in a Fe2+-ascorbate-linolenate system].

Using spin trapping method there were discovered and identified the radicals of linolenic acid formed when initiating its peroxidation by the system Fe2+-ascorbate. Mechanism of formation of linolenic acid radicals and their role in initiation of peroxidation were studied. A scheme of reactions of peroxidation initiation in the system Fe2+-ascorbate. linolenic acid is proposed.

Ascorbic Acid↗
PubMedDate not supplied

[Effect of chronic ethanol consumption on emotional stress in the white rat].

Chronic pain emotional stress (PES), paired action of the white noise and electric skin stimulation and chronic (during 7 months) ethanol consumption in white rats were shown to act in the same direction. Hypertension, decrease of respiratory rate and increase of Hildebrandt index were observed as a result of PES, ethanol consumption, and especially under PES during ethanol consumption. Ethanol consumption by the animals led to their growth retardation and increase of the spleen and heart mass. Accidental thymus involution was noted both under ethanol consumption and PES. Activation of lipid peroxidation and decrease of superoxide dismutase activity (of its mitochondrial form especially) as well as of Na+,K+-ATP-ase activity were observed in brain homogenates of the rats after PES, while the general ATP-ase activity remained unchanged. An increase of triiodothyronine level and the tendency to thyroxine level increase as well as a decrease of superoxide dismutase activity were observed in the blood serum of these animals. A tendency towards lipid peroxidation level decrease and to brain superoxide dismutase activity increase, as well as blood antioxidation activity increase (evaluated by transferrin and coeruloplasmin contents and by serum superoxide dismutase activity) and a decrease of thyroxine level were observed as a result of ethanol consumption. The mechanisms are discussed of the "anti-stress" action of short-term ethanol consumption and of the action of its chronic consumption, additive to PES.

Adenosine Triphosphatases↗
PubMedDate not supplied

[Psoralen-photosensitized formation of free lipid radicals at 77 degrees K].

It is shown by ESR method that 8-methoxypsoralen (8-MOP) under low temperature UV-irradiation has no influence on free radical formation of saturated fatty acids (FA). Under the same conditions the quantum yield of free radical photogeneration for unsaturated FA (oleate and limolenate) after addition of 8-MOP increased 7.5-15 times. The ESR spectrum of free radicals generated after interaction of 8-MOP with polyunsaturated FA, may be presented as superposition of signals-CH-(CH = CH)2-, -CH2CHCH2- and -CH2CH2. The molecular mechanism of photosensitized reactions is discussed.

Electron Spin Resonance Spectroscopy↗
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

[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↗