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Biomedical subjects

M V Ivanova

Publications and source records attributed to M V Ivanova.

At least 37 records · Page 2Linked to original sources
PubMed1994

Interaction of tocopherol with peroxyl radicals does not lead to the formation of lipid hydroperoxides in liposomes.

alpha-Tocopherol (alpha-TOH) is thought to act as a lipid-soluble antioxidant by scavenging the chain-carrying lipid peroxyl radical (LOO.), giving rise to alpha-TO. and LOOH. The aim of the present work is to test the possibility that alpha-TOH may also exert a protective action by converting LOO. into the parent, unoxidized lipid molecule (LH) with concomitant formation of O2- and T+O. To assess the relative contribution of the two pathways, the amounts of products accumulating were measured, i.e. LOOH and O2-, under conditions where lipid peroxidation was initiated at linear rates by the UV light-induced decomposition of AIBN. The overall conclusion of the study is based on the observation that significant amounts of O2- were produced, whereas the delta LOOH/delta alpha-TOH was considerably smaller than 1.0. A mechanism of one or two-electron oxidation of TOH is considered; according to it the phospholipid primary structure is restored (LOO.-->LH, breaking of the C-->O bond). This leads to the oxygen or superoxide anion-radical release accordingly.

Antioxidants↗
PubMed1993

[Creation of Delta mu(H)+ equal to 250 mV on the inner mitochondrial membrane is necessary, but not a sufficient condition for ATP synthesis].

Electron transport in the NADH-ferricyanide and succinate-->O2 chains and ATP synthesis in mitochondria under different incubation conditions have been studied. Ferricyanide which substitutes oxygen as a terminal acceptor provides the generation on the membrane potential, delta microH+, but does not initiate the functioning of the proton cycle. It is suggested that mitochondria can utilize delta microH+ only during the functioning of the redox chain under aerobic conditions. Presumably, under normal conditions oxygen implements two (but not one) functions; the second function of O2 may consist in the formation of a superoxide radical anion. Under conditions of decoupling caused by the free radical scavenger propylgallate, the ATP synthesis in mitochondria may be stimulated de novo through superoxide generation. This effect is abolished by superoxide dismutase.

Adenosine Triphosphate↗
PubMed1991

[Metabolism of cholesterol esters in cultured macrophages under the action of the calcium antagonists verapamil and nifedipine].

Using mouse macrophage cultures, the effects of verapamil and nifedipine on cholesterol ester metabolism were studied with special reference to the following parameters: i) incorporation of 14C-oleate into cholesterol esters (ChE), ii) contents of common and free cholesterol (FCh), iii) removal of 14C-oleate from ChE and incorporation of 3H-FCh into ChE and, iiii) excretion of 3H-Ch from the cells. Verapamil and nifedipine (10-100 microM) decreased the incorporation of 14C-oleate into ChE, increased the concentration of FCh but had no appreciable effect on the concentration of common Ch in macrophages cultured in the presence of acetylated low density lipoproteins. The drugs stimulated the removal of 14C-oleate from cellular ChE. The pharmacological concentrations (25-75 microM) of verapamil and nifedipine increased the excretion of 3H-Ch from ChE of macrophages in the presence of serum and high density lipoproteins. The results obtained suggest that verapamil and nifedipine mediate the antiatherosclerotic effect via reduction of intracellular synthesis of ChE, stimulation of ChE hydrolysis and cholesterol excretion from the cells.

Animals↗
PubMed1989

[Morphofunctional characteristics of thrombocytes in children with rheumatoid arthritis].

Altogether 205 children suffering from rheumatoid arthritis were examined for the morphofunctional status of platelets. Appreciable changes in the functional properties of platelets were revealed together with ultrastructural disorders. The correlation was noted between the characteristics under study as was their relationship with the disease activity and pattern.

Acid Phosphatase↗
PubMed1983

[Purification of antibiotics by ultrafiltration through semi-permeable membranes].

The process of purification of benzylpenicillin, penicillin V and erythromycin solutions with the use of semi-permeable membranes was studied. Practically complete separation of high-molecular admixtures and microbial colonies and separation of significant amounts of the colored compounds were shown to be possible. The purification process may be used effectively at the early stages of antibiotic production.

Anti-Bacterial Agents↗