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Biomedical subjects

M A Kisel'

Publications and source records attributed to M A Kisel'.

At least 19 recordsLinked to original sources
PubMed2001

Modification of humoral immune response in C57Bl/6 mice with a complex of alpha-fetoprotein and retinoid acid derivatives.

Amides of all trans-retinoic acid and O-phospho-L-threonine, O-phospho-L-tyrosine, and O-phosphoethanolamine injected intravenously in a dose of 6.8 microg/kg 1.5-3.4-fold increased the count of antibody-producing cells in the spleen of C57Bl/6 mice (primary immune response to sheep erythrocytes). Activity of the complex containing alpha-fetoprotein and L-threonine ligand did not differ from that of free retinoid. This complex holds much promise as a prototype of immunomodulators with a wide range of activity.

Animals↗
PubMed1997

[Formation of hemichrome during reaction of hemoglobin with polar phosphatidylcholine derivatives].

Polar phosphatidylcholine derivatives [1-acyl-2-lyso-sn-glycero-3-phosphocholine, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet-activating factor), 1-acyl-2-glutaryl-sn-glycero-3-phosphocholine, and 1-acyl-2-azelaoyl-sn-glycero-3-phosphocholine], which are formed in biological structures by enzymatic and free-radical reactions, were studied as effectors of the conversion of methemoglobin and oxyhemoglobin into an oxidized low-spin form referred to as hemichrome. It is shown that all these phosphatidylcholine derivatives act as effectors in the course of the transition of met- and oxyhemoglobin to hemichrome. Among the compounds studied, phosphatidylcholine derivatives containing glutaric and azelaic acids residues have the greatest effect on the rate of hemichrome formation.

Hemeproteins↗
PubMed1996

[Entrapment of antibiotics in liposomes containing phosphatidylethanol].

Antibiotic entrapment to liposomes containing phosphatidyl ethanol, a negatively charged phospholipid, as a lipid component was studied. Antibiotics of various groups such as doxorubicin, rifampicin and doxycycline were entrapped to liposomes consisting of a mixture of phosphatidyl choline and phosphatidyl ethanol at a ratio of 1:1 (v/v) or phosphatidyl choline alone. It was shown that the liposomes containing phosphatidyl ethanol were able to entrap the antibiotics in higher amounts by comparison with the liposomes containing phosphatidyl choline. Phosphatidyl ethanol in the composition of the liposomes had the highest effect on the entrapment of doxorubicin.

Anti-Bacterial Agents↗
PubMed1995

[Synthesis and properties of membrane-addressed antioxidants based on phosphorylated pyrocatechols].

Amphiphilic membrane-addressed antioxidants differing in their hydrophobic-hydrophilic balance, 3,5-di-tert-butyl-2-hydroxyphenyl phosphate, (3,5-di-tert-butyl-2-hydroxyphenyl)hexadecyl phosphate, and (3,5-di-tert-butyl-2-hydroxyphenyl)-5-cholesten-3 beta-yl phosphate, were synthesized starting from 3,5-di-tert-butyl-o-quinone. Even at 10(-8) M concentration, 3,5-di-tert-butyl-2-hydroxyphenyl phosphate and (3,5-di-tert-butyl-2-hydroxyphenyl)hexadecyl phosphate inhibit formation of malonic aldehyde during peroxidation of lipids from rat brain homogenate initiated with a Fe(2+)-ascorbate system. At 10(-4) M and higher concentrations of antioxidants in the brain homogenate, the formation of malonic aldehyde is inhibited more efficiently than with tocopherol at the same concentrations.

Animals↗
PubMed1992

[Lipolysis in model membranes in the presence of positively charged soluble proteins].

Phospholipase A2 hydrolysis of neutral and negatively charged lipid membranes modified by positively charged proteins has been studied using liposomes composed of either dioleoylphosphatidylcholine (DOPC) or dioleoylphosphatidylglycerol (DOPG) alone or their equimolar mixture in the presence of cytochrome c, histone H1, cytochrome b5, and polylysine. Twenty minutes after the reaction had been initiated, DOPC hydrolysis was 58%, while that in the equimolar mixture with DOPG was 35%. DOPG hydrolysis was more complete in binary mixtures of liposomes. The same was observed for liposomes in the presence of cytochrome c. Hydrolysis of phospholipids in binary liposomes in the presence of histone H1 was 3 times faster than that in protein-free liposomes. In the presence of polylysine the rate of DOPG hydrolysis was decreased. The results obtained are suggestive of electrostatic interactions between hydrophilic proteins and negatively charged phospholipids, the phospholipase A2 catalytic activity being affected by these interactions.

Cytochrome c Group↗
PubMed1989

[Study of phospholipase A2 specificity in substrate-containing structures having different supramolecular organization].

The specificity of snake venom phospholipase A2(PLA2) towards a number of phospholipid (PL) substrates, e. g., phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) organized in Triton X-100 mixed micelles, liposomes and proteoliposomes was studied. PC was shown to be more rapidly hydrolyzed in micelles. For other PLs, the rate of hydrolysis decreased in the following sequence: PC greater than PI greater than PE greater than PG. The incorporation into micelles of a non-hydrolyzable by PLA2 sphinogomyelin which, similar to PC, has a choline group, resulted in an increase of PLA2 specificity towards PL that are known to be devoid of this group: PE greater than PI greater than PG greater than PC. Quite a different picture was observed in bilayer liposomal structures: PI congruent to PE greater than PC greater than PG. The incorporation of cytochrome P-450 into liposomes caused the acceleration of PE and PG hydrolysis. The course of the PLA2-catalyzed hydrolysis in model membrane structures seems to be governed primarily by the supramolecular organization and localization of the substrate in the bilayer, but not by its chemical structure.

Animals↗
PubMed1987

[Fatty-acid initiated auto-oxidation of hemoglobin].

The interaction of fatty acids (FA) with oxyhemoglobin (HbO2) was investigated. It was found that under effect of FA HbO2 is converted into the oxidized low-spin form, i. e., hemichrome. An increase in the level of reactive oxygen species was registered by the ESP method, using the spin traps, 1.2-dioxybenzo-3.5-disulphonate (tiron) and 5.5-dimethylpyrroline-1-oxide (DMPO). To investigate the nature of radical particles, the OH radical traps. thiourea and D-mannitol, as well as superoxide dismutase (SOD) and catalase were employed. The mechanism of interaction of HbO2 and FA is discussed; its feasible physiological role in the functioning of erythrocytes is postulated.

Animals↗
PubMed1987

[Effector role of fatty acids in the transformation of methemoglobin into hemichrome].

The interaction of fatty acids (FA) with methemoglobin (met-Hb) was investigated. It was found that under the action of FA met-Hb is rapidly converted into a low-spin form (the so-called hemichrome). This process is reversible as proved by the addition of bovine serum albumin into the system. Using differential spectrophotometry, the efficiency of FA action on met-Hb depending on concentration and nature of FA was estimated. Using the circular dichroism (CD) method, it was demonstrated that under the action of FA the concentration of R-conformation in the met-Hb molecule is increased. The stoichiometry of the hemichrome complex with FA at various FA concentrations was assessed. A comparative analysis of the effect of various detergents with known structures on met-Hb was carried out. The mechanism of met-Hb conversion into hemichrome is discussed.

Animals↗
PubMed1985

[Effect of phosphatidylglycerol on the incorporation process of cytochrome P-450 in liposomes from dimyristoylphosphatidylcholine].

Using the electron paramagnetic resonance (EPR) method with spin-labeled fatty acids and gel-penetrating chromatography, the effect of phosphatidylglycerol on cytochrome P-450 incorporation into liposomes from dimyristoylphosphatidylcholine was investigated. An addition of phosphatidylglycerol caused an increase in the protein content of the proteoliposomes as well as their accelerated formation at temperatures below and above the liposome phase transition temperature (Ts). The dependence of the proteoliposome formation rate on the phosphatidylglycerol content in the liposome mixture is described by complex kinetics with a maximum in the presence of 10 mol.% of the negatively charged phospholipid. The mechanism of proteoliposome formation is discussed in terms of asymmetric distribution and phase state of the phospholipids in the original vesicles.

Animals↗
PubMed1981

[Effects of phospholipids on oxidative demethylation of dimethylcyclohexylamine by cumene hydroperoxide involving methemoglobin].

The reaction of oxidative demethylation of N-dimethylcyclohexylamine by cumene hydroperoxide involving methemoglobin was studied. Data from differential spectroscopy and kinetic analysis revealed the formation of a methemoglobin--N-dimethylcyclohexylamine--cumene hydroperoxide complex. The inhibiting analysis revealed the radical stages in the process of demethylation. An addition to the reaction mixture of phosphatidyl serine, phosphatidyl inositol and lysophosphatidyl choline at a ratio of 50 divided by 500 molecules per 1 molecule of protein increased the rate of the reaction product accumulation 2--3-fold. Phosphatidyl choline and the ionic detergent sodium cholate did not practically affect the reaction rate under the given experimental conditions. The nature of the activating effect of some phospholipids on oxidative demethylation is discussed.

Animals↗
PubMedDate not supplied

[The characteristics of the radiation-initiated peroxidation of the phosphatidylcholine making up liposomes containing phospholipids which are susceptible to free-radical fragmentation].

The regularities of accumulation of conjugated dienes and thiobarbituric acid (TBA)-reactive substances under gamma-irradiation of liposomes from rat liver phosphatidylcholine (PC) and its mixtures with the resistant to lipid peroxidation saturated phospholipids and bovine brain sphingomyelin (SM) were studied. It was established that the incorporation of negatively charged dipalmitoylphosphatidylglycerol (DPPG) and dipalmitoylphosphatidylethanol (DPPET) into lipid bilayer resulted in the increase of primary and secondary products of LPO, whereas neutral dipalmitoylphosphatidylcholine (DPPC) and SM involving in the phospholipid mixtures inhibited the peroxidation of PC. For anionic phospholipids, DPPG had more profound activating action on LPO, amongst the neutral phospholipids SM was more potent inhibitor of the reaction. Unlike DPPET and DPPC, DPPG and SM were subjected to free radical fragmentation on gamma-radiation. It is suggested that the intermediates and products of free radical fragmentation may modulate the progress of LPO.

Adenosine Triphosphate↗