Biomedical subjects
Publications and source records attributed to M M Levachev.
Chemical composition and technology of preparation of fat part of breast milk substitutes closed in lipid composition of prototype (in PUFA, phospholipid and cholesterol contents) are presented. It was shown that chosen combination of fats with antioxidant vitamins provides effective defense of food against spoiling during storage.
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Wistar male rats received polysynthetic diets incorporating lard or fish of different oxidation degree as the sourse of fat. The feeding lasted 4 weeks. In the liver of rats on fish oil diet the activity of the enzymes of xenobiotic metabolism phase I (monooxigenase system, epoxide hydrolase, carboxyl esterase) and phase II (native and activated UDP-glucuronosyl transferase, glutathione transferase) located both in microsoma membranes and in cytozole was higher than in the animals on lard diet. The enzyme activity was much more enhanced in the use of oxidated fish oil. No effect of fish oil on serum and lysosome enzyme activity and rat hepatic structure was found.
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The influence of dietary essential fatty acids on the immune functions and nonspecific resistance of male Wistar rats weighing 135.0 +/- 3.2 g was investigated after 3 months feeding. Rats were fed isocaloric purified diets containing 24% of fat (combinations of lard, sunflower oil and fish oil, eiconol, this providing the ratios of omega 6/omega 3 fatty acids equal to 1.1; 2.1; 6.1; and 49.0. An increase of immune responsiveness and nonspecific resistance in the groups fed diets with the minimal ratios of omega 6/omega 3 fatty acids as compared to that in rats fed a diet with ratio 49.0 was noted. Fatty acid analysis of peripheral lymphoid organs tissue lipids showed an increase in percentage of eicosenic omega 3 fatty acids in rats fed diets with increased content of polyunsaturated fatty acids omega 3.
Purified diets for rats contained 24% fat, with presented with the mixture of sunflower and fish oils whose combination yielded ratios of omega 6 to omega 3 fatty acids equal to 99 0, 49 0, 5 2, 1.9 and 0.12. The alterations in fatty acid composition of blood plasma and the liver were noticed, which manifested in increased omega 3 fatty acid levels in proportion to their dietary content. The elevation of PUFA proportion in the diet increased TBA-reactive substances in the liver. Using radioimmunoassay the levels of PGF2 alpha, TxA2 and PGI2 were determined. The decrease of arachidonic acid as part of tissue lipids caused an inhibition of PGF2 alpha formation in the liver, TxA2 and PGI2 in blood plasma, that showed a possibility of influence the ratio omega 6/omega 3 PUFA in a diet on eicosanoid synthesis by substrate regulation. These results suggest that for characteristics of dietary fat the ratio omega 6/omega 3 PUFA as a criterion reflecting the biological action of two families of essential fatty acids should not be used.
Measurements were made of the composition of fatty acids contained by platelet lipids in practically healthy persons depending on the diets. Both the amount of essential fatty acids in the diet and their appurtenance to the omega-6 or omega-3 families were established to influence the composition of platelet fatty acids. The conclusion is drawn about the necessity of taking into consideration that diet influence while using platelet as a test system for estimating physiological and pathological conditions of the body.
HSA structure was studied in healthy subjects and cancer patients using infrared spectroscopy. No significant differences were observed although the intensity of valent C-H fluctuation lines in alkyl groups of HSA was slightly increased in cancer patients. Gas-liquid chromatography established changes in the profile of polyunsaturated fatty acids binding to HSA in cancer patients. The data obtained suggest inhibition of omega-6 pathway of fatty acid metabolism and activation of omega-3 pathway. Marked binding of POL products to serum albumin was found nonspecific and was considered evidence of protective function of that protein.
In aborigines from the costal and continental areas of Chukotka who differ in dietary polyunsaturated fatty acid (PFA) n-3 intake, specific features of the composition of fatty acids in cell membranes were revealed in a model of erythrocytes: the costal inhabitants showed a higher proportion of PFA n-3 mainly through eicosapentaenic acid and lower proportion of major PFA n-6. With this, plasma lipoprotein lipids in whose composition the acids transported to the cell membranes displayed the similar regularities in changes in fatty acid composition. Only a far larger portion of eicosapentaenic acid in the cell membranes from the costal inhabitants than from the continental inhabitants was associated with greater mass of the left ventricular myocardium. It was concluded that transport of lipids containing high PFA n-3 in the composition of lipoproteins to the cell membranes caused an increase of the acids in them and, evidently, a change in physicochemical and, therefore, functional properties of cells.
Studies of the actual nutrition and wide spectrum of biochemical, haematological, and anthropometric indices in the representatives of the native population of Kamchatka and Chukotka showed that along with the significant changes in nutritional patterns due to the added products, local sources of feeding (fish, sea mammals, deer meat) greatly contribute to fulfilling the physiological requirements and exert a specific effect on metabolic processes. This is mostly associated with the features of lipid metabolism as a result of marine fat intake. Recommendations on the rational nutrition organization in these regions are discussed.
A study was made of the fatty acid composition of erythrocytes in the Chukchi aged 30 to 59 with myocardial hypertrophy and in controls. In erythrocytes of the Chukchi the percentage of polyunsaturated fatty acids of omega-3 series including eicosapentaenoic acid was increased (C 20:5), and the percentage of linoleic acid and arachidonic acid was decreased (C 18:2 and C 20:4, respectively) as compared to similar indices of erythrocytes in Muscovites. Myocardial hypertrophy was diagnosed in the Chukchi in whom the percentage C 20:5 in erythrocytes was higher and exceeded that in PL. It was assumed that changes in the fatty acid composition of cell membranes played certain part in disorder of their function and the development of myocardial hypertrophy in the Chukchi.
TLC, GLC and GC-MS methods were applied for studying the fatty acid composition of rat cerebellum phospholipids. 75 male Wistar rats had a diet without fat for 6 weeks and then a diet with linseed oil, fish oil in combination with lard and mixture of sunflower oil with lard (control group) for 3 months; PUFA omega 6/omega 3 rations were 0.27; 0.5 and 45.0. PUFA omega 3 in all fractions were represented mainly by 22:6 omega 3 (0.2-12.0%) acid and its share depends on the total PUFA omega 3 amount in the diet. The absence of 18:3, 20:5 and 22:5 omega 3 in cerebellum lipids, fed in great amount with test diets, suggested that these acids are rapidly desaturated and elongated to 22:6 omega 3 at the blood-brain barrier. Established competitive inhibition of desaturases responsible for the synthesis of tissues PUFA omega 6 and omega 3 proves the expressed regulatory effect of alimentary factor on brain lipids.
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A comparative analysis of the fatty acid composition of phosphatidylcholines (PC) and sphingomyelins (SP) of lipoproteins (LP) of low and very low density was performed in the blood plasma of Eskimos (indigenous population of the Chukot Peninsula) in myocardial hypertrophy and in the control group as well as in the control group of Muscovites. Some characteristic features of the fatty acid composition of low density LP PC and SP were revealed in Eskimos in myocardial hypertrophy. The role of changes in the transport of fatty acids of low density LP PC and SP of the blood plasma in the myocyte membrane liquidity as well as in the synthesis of biologically active prostacyclin revealed in myocardial hypertrophy was discussed.
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