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Biomedical subjects

A V Kariakin

Publications and source records attributed to A V Kariakin.

At least 19 recordsLinked to original sources
PubMed2002

[Tumor necrosis factor, interleukin-6, endotoxin and procalcitonin in septic shock in patients with hematologic neoplasms].

AIM: To study changes in proinflammatory markers and mediators in septic shock in patients with hematologic malignancy (HM). MATERIAL AND METHODS: The examination of 33 patients with HM and septic shock included measurement of plasma concentrations of tumor necrosis factor (TNF), interleukine-6 (IL-6), endotoxin, procalcitonin (PCT) 12-24 hours before and each 12 hours after shock; registration of central hemodynamics parameters, the condition severity by APACHE II. RESULTS: Out of 33 patients 18 died of refractory shock, 15 survived the shock. Within the first shock hour TNF fell from 571.2 +/- 195 to 115.8 +/- 71.1 pg/ml (p < 0.02), later being stable. In those who died and survived TNF was the same. IL-6 fall was seen 36 hours after shock and was observed in the survivors; in those who died IL-6 was unchanged. Endotoxin in the blood was detected in 21 of 33 patients. In the survivors endotoxinemia declined after 2 days of treatment. 72 hours after beginning of the shock the survivors had no endotoxin. In shock APACH II severity of the patient's condition was graver in patients with endotoxinemia than without it (31.6 +/- 1.6 and 28.1 +/- 1.6 scores, p < 0.05). Blood endotoxin levels and APACHE II scores correlated (r = 0.24, p < 0.05) positively and negatively with deficiency of buffer bases (r = -0.29, p < 0.05) and blood pH) r = -0.3, p < 0.05), left ventricular contractility index (r = -0.46, p < 0.01) and right ventricle (r = -0.52, p < 0.01), mean AP (r = -0.22, p < 0.03). PCT concentration was lower before shock than on its hour 1 (4.2 +/- 2.9 and 6.9 +/- 1.1 ng/ml, p < 0.05). No significant changes in PCT were found later. CONCLUSION: PCT is a specific marker of a severe infection. Rapid elimination from the blood of TNF and IL-6 makes them inadequate in sepsis diagnosis. Endotoxinemia aggravates the patients condition. Positive LAL-test results were obtained in gram-negative and fungal infections.

Adult↗
PubMed1990

[Oxygenase activity of cytochrome P-450 electrochemically reduced in the presence of methylviologen].

An electrochemical system of cytochrome P-450 reduction in the presence of the water-soluble redox carrier methylviologen has been developed. In this system cytochrome P-450 effectuates a steady-state demethylation of dimethylaniline and hydroxylation of aniline. The results of control experiments suggest that the above reactions are mediated by cytochrome P-450. The effect of the peroxidase reaction is excluded by an addition of high concentrations of catalase to the incubation mixture. At the same time the hydroxylation of these substrates is accompanied by methylviologen demethylation.

Animals↗
PubMed1981

[Stoichiometric protein-lipid interactions in liver microsomal membranes measured by the induction-resonance energy transfer method].

The stoichiometry of proteins and lipids in the microsomal membranes of the liver were studied by the induction-resonance energy transfer method. The energy was transferred between the fluorescent tryptophane residues of membrane proteins and fluorescent probes (pyrene and 4-dimethylaminochalcone) located in the microsomal lipid bilayer. It was assumed that the rate of protein fluorescence is correlated with protein mass. All microsomal proteins were arbitrarily divided into two groups, i.e. proteins located at a distance of more ("peripheral" proteins) and less than 30 A from the lipid bilayer surface. The former proteins made up to 14-24% of total microsomal protein, while microsomal ghosts--less than 10%. In the microsomes the bulk of other proteins is located at an average distance of about 19-26 A from the lipid bilayer surface, while the grosts--at about 4-9 A. Treatment of the ghosts with pronase results in approximation of the protein mass locus with the lipid by about 5 A. In this way the generation of ghosts and their treatment with pronase cause a loss of proteins predominantly from the peripheral parts of the microsomal membrane.

Animals↗
PubMed1981

[Effect of incorporation and removal of cholesterol on the lipid bilayer viscosity and the rate of oxidative reactions in rat liver microsomal membranes].

The interrelationship between the lipid bilayer viscosity and the rate of oxidative reactions in rat liver microsomal membranes were investigated. The viscosity of the lipid bilayer is increased upon incorporation of cholesterol into the microsomes and is decreased upon its removal. This results in a corresponding decrease and increase of the rate of cytochrome b5 reduction by NAD(P)H. The rates of cytochrome P-450 reduction and oxidation of dimethylaniline, aniline, p-nitroanisol and NAD(P)H, as well as those of oxygen uptake and lipid peroxidation do not depend on the bilayer viscosity. Hence only the reactions of cytochrome b5 reduction by NADH- and NADPH-specific flavoproteins are diffusion-dependent processes in the microsomal oxidation chain.

Animals↗
PubMed1980

[Kinetics of formation of the enzyme-substrate complexes of cytochrome P-450 in rat liver microsomes].

A spectrophotometric study of the kinetics of binding of I and II type substrates to cytochrome P-450 from rat liver microsomes has been carried out. The rates of binding of the substrates of type I to a low spin form of the enzyme and those of substrates of type II to a high spin form are approximately the same. The interaction of type II substrates with a low spin form of cytochrome P-450 occurs at a 15--20-fold lower rate. The dependence of initial reaction rates on substrate concentration describing the Michaelis equation suggests that the reaction occurs in more than one step both for type I and II substrates. The data obtained allowed to develop a two-step scheme of reactions, according to which the substrate in the first step rapidly and irreversibly interacts with the binding centers, which can be located both in the microsomal membrane and in cytochrome P-450. At the second stage the substrate in transferred into the active center of cytochrome P-450, resulting in a formation of complexes with specific optical properties.

Animals↗
PubMed1979

[Electrochemical analysis of microsomal cytochromes].

The electrochemical behaviour of the electron transfer proteins -- cytochromes b5, c and P-450 was studied by classical polarography and electrolysis with spectrophotometric monitoring. It was shown electrons are directly transferred from the electrode to oxidized cytochromes c and b5. Cytochrome P-450 is not reduced on the electrodes. However, the reduced inactivated from of cytochrome P-420 was detected at high potential values (-1,5 v).

Animals↗
PubMed1975

[Respiration and oxidative phosphorylation in isolated liver cells].

Two methods of preparation of isolated rat liver cells were studied. In the first method, the dissociative effect of enzymes and mechanical treatment and Hanks' solution as isolation medium were used. In the second method, enzymes were replaced by compexon-ethylenediamine tetraacetate and Hanks' solution -- by 0.25 M sucrose. The cells obtained by the second method are able of oxidative phosphorylation and keep better NAD-H-cytochrom c-reductase. The fine structure of these cells revealed by means of electron microscopy analysis was well preserved.

Animals↗