[Comparison of results of the fluorescent method in the determination of atherogenic lipids and the data of biochemical methods]. / Sravnenie rezul'tatov fliuorestsentnogo metoda opredeleniia aterogennykh lipidov s dannymi biokhimicheskikh metodov.

Devices based on assessment of fluorescence of special "probes" incorporated in lipoprotein particles of the blood were developed at Research Institute of Physicochemical Medicine of the Ministry of Health of the Russian Federation. The resultant value is considered to reflect the sum of total cholesterol and triglycerides. The present study was aimed at elucidation of the relationship between the fluorescent and enzymatic methods, the enzymatic method realized by the Centrifikhem autoanalyzer. Coronary angiography during which blood for analysis by the two methods was collected was carried out in 182 patients aged 26 to 68 (mean age 49). Analysis of correlations revealed a direct relationship of the fluorescent value with the sum of total cholesterol and triglycerides, with triglycerides, with total cholesterol, and an inverse relationship with high-density lipoproteins. Using multifactorial regression analysis, the level of fluorescent parameter could be predicted only on the basis of triglyceride level and ratio of total cholesterol to high-density lipoproteins. Using the linear regression equation it is possible, if the fluorescent parameter value is available, to calculate triglyceride level. No relationship of the fluorescent parameter or triglycerides with the dissemination of coronary atherosclerosis, which is characteristic of total cholesterol sum, was detected.

[Food supplement containing ω-3 polyunsaturated fatty acids prevents experimental thrombotic occlusion of coronary arteries in dogs]. / Pishchevaia dobavka, soderzhashchaia omega-3 polinenasyshchennye zhirnye kisloty, predotvrashchaet éksperimental'nuiu tromboticheskuiu okkliuziiu koronarnoi arterii u sobak.

The antithrombotic effect of fish oil (FO) cannot be explained by its action on platelets. FO may act on the activity of the fibrinolytic system. A food additive of the oil was studied for its effects on thrombosis and fibrinolysis in a canine model of experimental coronary thrombosis. During 4 weeks, 6 animals were fed a diet containing Sardinops sagax melanosticta oil (400 mg/kg/day) (omega 3-polyunsaturated fatty acids (omega 3-PUFA), 5 dogs had isocaloric amounts of olive oil (00), 5 animals were controls on a routine diet. Thrombosis was induced by anodal current, 170 mcA, through the silver electrode inserted into the coronary artery across its wall, thus contacting with the intima of the preconstricted left circumflex artery. Plasma levels of eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) and euglobulin clot lysis time were determined before and after diet. The frequency of occlusion for 180 min after power turning-on was 5/5 in the 00 and control groups, but 1/5 in the FO group. Thus, dietary supplementation with FO which caused a substantial increase in plasma omega 3-PUFA prevented coronary artery occlusions without decreasing euglobulin clot lysis time. So, while producing antithrombotic effects, the oil failed to affect fibrinolysis in this model of thrombosis.

[Several peculiarities of the interaction of troponin T and troponin C of skeletal and cardiac muscle]. / Nekotorye osobennosti vzaimodeistviia troponina T i troponina C skeletnykh i serdechnykh myshts.

Using several independent methods, the interaction between troponin T and troponin C from skeletal and cardiac muscles was studied. It was found that troponin T and troponin C from skeletal muscles form a complex whose stability depends on Ca2+ concentration. Study of interactions between these troponin components demonstrated that both electrostatic and hydrophobic forces are involved in the complex formation. Cardiac troponin T and troponin C weakly interact with each other irrespective of experimental conditions. It was assumed that the weakening of interactions between the components of cardiac troponin is due to structural peculiarities of cardiac troponin T.

[Troponin from th bovine heart: isolation and study of cation-binding properties using a 3-dimethylaminonaphtheurodine fluorescent probe]. / Troponin serdtsa byka: vydelenie i izuchenie kationsviazyvaiushchikh svoistv s pomoshch'iu fluorestsentnogo zonda dimetilaminoaftéirodina.

A method for isolation of bovine heart troponin has been developed. The troponin complex was separated into constituent components. The fluorescent probe 3-dimethylaminonaphtheurodine binds to heart troponin: the fluorescence of the troponin--dimethylaminonaphtheurodine complex is increased with a rise in Ca2+ concentration from pCa 8 to pCa 5. The apparent constant for Ca2+ binding to heart troponin calculated from the changes in fluorescence of the troponin-dimethylaminonaphtheurodine complex is equal to 2,1 . 10(6) M(-1). The corresponding constant for Sr2+ binding by heart troponin is 5 . 10(5) M(-1), Mg2+ have no effect on Ca2+ and Sr2+ binding. The results obtained suggest that heart troponin contains Ca-specific binding sites and that the binding of Ca2+ to these sites evokes conformational changes, which are registered by means of the fluorescent probe. The Hill coefficient for the conformational changes of heart troponin induced by Ca2+ and Sr2+ measured with the probe is equal to unity. The use of 3-dimethylaminonaphtheurodine as a marker of conformational changes allows to compare the cation-binding properties of troponin from heart and skeletal muscles.