Центральная Научная Библиотека УрО РАН

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   M 46

    Medvedeva, N.
    Study of rare encounters in a membrane using quenching of cascade reaction between triplet and photochrome probes with nitroxide radicals [Text] / N. Medvedeva, V. Papper, G. I. Likhtenshtein // Physical Chemistry Chemical Physics. - 2005. - Vol. 7, № 18. - P3368-3374. - Библиогр. : с. 3373 (26 назв.)

ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Аннотация: Measurements of active encounters between molecules in native membranes containing ingredients, including proteins, are of prime importance. To estimate rare encounters in a high range of rate constants (rate coefficients) and distances between interacting molecules in membranes, a cascade of photochemical reactions for molecules diffusing in multilamellar liposomes was investigated. The sensitised cascade triplet cis-trans photoisomerisation of the excited stilbene involves the use of a triplet sensitiser (Erythrosin B), a photochrome stilbene-derivative probe (4-dimethylamino-4 -aminostilbene) exhibiting the phenomenon of trans-cis photoisomerisation, and nitroxide radicals (5-doxyl stearic acid) to quench the excited triplet state of the sensitiser. Measurement of the phosphorescence lifetime of Erythrosin B and the fluorescence enhancement of the stilbene-derivative photochrome probe, at various concentrations of the nitroxide probe, made it possible to calculate the quenching rate constant kq= 1.1*10 15 cm2 M-1 s-1 and the rate constant of the triplet-triplet energy transfer between the sensitiser and stilbene probe kT= 1.0*1012 cm2 M-1 s-1. These values, together with the data on diffusion rate constant, obtained by methods utilising various theoretical characteristic times of about seven orders of magnitude and the experimental rate constants of about five orders of magnitude, were found to be in good agreement with the advanced theory of diffusion-controlled reactions in two dimensions. Because the characteristic time of the proposed cascade method is relatively large (0.1 s), it is possible to follow rare collisions between molecules and free radicals in model and biological membranes with a very sensitive fluorescence spectroscopy technique, using a relatively low concentration of probes.

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   N 52


    New insights in to the treatment of myocardial infarction / P. Sarapultsev, O. N. Chupakhin, A. Sarapultsev, M. Rantsev, S. Medvedeva, I. Danilova // International journal of experimental pathology. - 2012. - Vol. 93, № 1. - С. 18-23. - Bibliogr. : p. 23 (18 ref.)

ББК 54
Рубрики: ХИМИЧЕСКИЕ НАУКИ
Кл.слова (ненормированные):
INFLAMMATION -- L-17 COMPOUND -- MYOCARDIAL INFARCTION
Аннотация: This study investigated the effects of the L-17 compound of the group of substituted 5R1, 6H2-1,3,4-thiadiazine-2-amines on the inflammatory cellular infiltration and myocardial remodelling which occurs after acute myocardial infarction (MI) in rats. The study is based upon recent clinical and experimental work which demonstrated the role of local and systemic inflammatory reactions in postinfarction remodelling. Acute MI in rats was induced by left coronary artery coagulation. Animals were sacrificed on day one, five and seven after MI induction. The myocardiumal samples were taken from all parts of the heart and examined by histology. This included areas of infarction, infraction and areas that were peri-infarctiom and left ventricular areas distant from the damaged tissues. Serum activity of creatine phosphokinase (CPK), aspartate aminotransferase (AST), isoenzymes 1 and 2 and lactate dehydrogenase (LDH1-2) were investigated on the same three days, before and in the process of MI development was investigated (at days 1, 5 and 7). The L-17 compound to not only decreased the area of initial infarction but also changed the pattern of inflammatory reaction in the affected myocardium fundamentally. Laboratory studies of effects of L-17 compound on the development and course of experimental MI showed that administration decreased blood AST and CPK levels significantly and provided useful the data about the correlation between the activity of these enzymes and the dimensions of the significantly necrotic area. In this model of experimental MI the use of the L-17 compound induced led to the replacement of the exudative destructive inflammation that is seen under standard conditions with a more cellular productive pattern of inflammation, with associated reduction in initial necrosis area and the, decrease in myocardial ischaemia and reperfusion injury may account for the accelerated repair process

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