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Models of experimental dyslipoproteinemias have been developed by using non-inbred rats (males and females) and guinea-pigs. Administration of cholesterol (C) with fats and supplementation of 4-hydroxy-6-methyl-2-thiouracil to male rats and that of C in the mixture of fats to guinea-pigs have been demonstrated to lead to the development of atherogenic dyslipoproteinemias. Genfibrozil, cholestyramine and vasosan II, a new pectin-enriched formulation, promoted normalization of the impaired serum lipoprotein spectrum caused by exogenous C administration. Bilateral ovariectomy in female rats induced atherogenic dyslipoproteinemia. The use of the estrogen derivative methyl ether of 6-oxa-D-homo-8-isoestrone normalized lipid and lipoprotein metabolic disturbances.

The level of lipids and apolipoproteins was studied in the serum of patients with various degrees of obesity without hormonal impairments in order to find interrelationship between obesity and atherosclerosis development. 14 men and 42 women aged 19-59 years were examined. Concentration of triglycerides and very low density lipoprotein (VLDL) cholesterol was distinctly higher in obese patients of both sexes than in normal weight persons. However, content of apo A-I and apo B was similar in blood of both obese and normal persons, while concentration of apo E was higher in obesity. In obesity, the ratio HDL cholesterol/A-I was decreased, thus indicating that the HDL3/HDL2 ratio was altered, showing a decreased content of the latter subfraction. The findings suggest that impairment in metabolism of mainly HDL and VLDL subfractions occurred in patients with obesity. These impairments were atherogenic and may be responsible for a high risk for atherosclerosis and heart ischemic disease in obese patients.

Experiments on rats, guinea pigs and rabbits with experimental dyslipoproteinemia have revealed that the new water-soluble high-molecular weight polymers containing digitonin (ED) or a quaternary nitrogen atom (EA) have a more marked hypolipidemic action than cholestyramine and normalize lipoprotein metabolism. The digitonin-containing enterosorbent has been shown to decrease the absorption of 4-14C-cholesterol, while the nitrogen-containing enterosorbent diminishes the absorption of 3H-cholic acid.

A procedure of theoretical determination of the dependence of protein molecule charge on the medium pH has been developed. The suggested procedure allows calculating the protein pI value, the molecule charge at the definite pH value, as well as the corresponding values for the protein molecule. Calculations for insulin, apo A-I and apo A-II molecules have been carried out. Calculated pI values are equal to 5.25, 5.64 and 4.86, respectively. A comparison of the theoretical curves and experimental data allows obtaining information of the molecule structure. Carboxyl groups with abnormally high pK values are discovered, that, probably, indicates to the direct interaction of two COOH-groups. A supposition is made on the most probable arrangement of the functional fragments in apo A-I and apo A-II molecules.

The bile acid sequestering agent Vasosan P is a new form of pectin-enriched cholestyramine (20%), saccharose (5%) and sorbic acid (0.18%). In comparison with cholestyramine Vasosan P has a more marked hypolipidemic effect in experiment. Vasosan P is remarkable for good organoleptic properties. It is effective in treating patients with type IIa hyperlipoproteinemia and practically has no side effects as cholestyramine.

Levels of some fractions of blood neutral lipids and lipoperoxides were compared in the families of patients with coronary heart disease. The patients and their relatives (including healthy ones) were found to show a statistically significant increase in the atherogenic index, total cholesterol, low density lipoprotein cholesterol, triglyceride, total lipid, and lipoperoxide concentrations and a decrease in high density lipoprotein cholesterol levels as against controls. The changes in the values of lipids and lipoperoxides in the families of patients with coronary heart disease were homogenous and might be one of the pathogenetic links in the formation of hereditary predisposition to atherosclerotic cardiovascular diseases which might be detected in a prehospital period.

In men with increase of age from senile to longevity content of total cholesterol was practically unaltered (182 and 184 mg/100 ml), concentration of cholesterol in LPHD was increased from 52 mg up to 58.3 mg/100 ml simultaneously with unaltered content of LPLD cholesterol (102 mg/100 ml) and of LPVLD cholesterol (27.1 and 27 mg/100 ml). Triglycerides decreased from 136 mg down to 101 mg/100 ml. In women content of total blood cholesterol was about 218 mg/100 ml in senile age and 204 mg/100 ml in longevity and concentration of LPHD cholesterol--61 mg and 64.6 mg/100 ml, respectively. Contrary to men, in women a distinct decrease in content of LPLD cholesterol (from 127 mg to 110 mg/100 ml) as well as of triglycerides (from 154 to 145 mg/100 ml) were found on transition from senile age to longevity. Concentration of the apolipoproteins studied was unaltered in men on transition from senile age to longevity and in women concentration of apolipoprotein A-I decreased from 143 mg to 130 mg/100 ml and of apo-E from 11.1 mg to 9.2 mg/100 ml. The decrease in LPLD cholesterol content and increase of LPHD cholesterol, simultaneously with relatively low content of total blood cholesterol, appear to be considered among the reasons responsible for longevity and lesser risk of heart ischemic disease.

Particle diameters of very low density lipoprotein (VLDL)--29.5, 36.3, 22.0; low density lipoprotein (LDL)--18.4, 19.0, 22.0; high density lipoprotein subclass 2 (HDL2)--8.5, 9.7, 15.0; and high density lipoprotein subclass 3 (HDL3)--7.2, 7.6, 14.4 nm were evaluated by means of flotation velocity (FV), optical mixing (OM), and fluorescent probe (FP) respectively. On the basis of the calculated frictional ratio f/f0 from FV and OM data for VLDL, LDL, HDL2, and HDL3--1.51, 1.07, 1.31, and 1.10, assuming the sphericity lipoprotein particles as an index for structural peculiarity a conclusion is made that in contrast to LDL and HDL3 HDL2 have asymmetrical weight distribution per particle volume. A model is suggested suitable for the structural peculiarity of VLDL established on the data of three independent methods which outlines VLDL as particles consisting of several associated subunits with the mean diameter of about 20 nm.

It is established that low-density lipoproteins (LDLP) are present in the human vascular wall in the form of complexes with glycosaminoglycans. These complexes dissociate in an electric field and in salt solutions which are usually used for isolating lipoproteins by ultracentrifugation. Besides, in distinction from blood plasma LDL, the LDL of the vascular wall are characterized by a higher flotation rate and asymmetric distribution according to the flotation rate.

Content of apo A-I constitute 136 mg/100 ml, of apo A-II--64 mg/100 ml and of apo E--10 mg/100 ml in blood plasma of 20--60 years old men with normal concentration of cholesterol (alpha-CS) in blood. In the patients with hyper-alpha-lipoproteinemia (alpha-CS was above 76 mg per 100 ml) concentrations of apo A-I and apo A-II were distinctly higher (173 and 71 mg per 100 ml, respectively) and that of apo E--was lower (8 mg per 100 ml) as compared with the healthy persons. Under the conditions of hypo-alpha-lipoproteinemia (alpha-CS was below 37 mg per 100 ml) the contents of apo A-I and apo A-II were decreased down to 116 and 50 mg per 100 ml, respectively, and that of apo E--increased up to 12 mg per 100 ml. Concentration of the total fraction of high density lipoproteins (LPHD), LPHD2 and their subfraction LPHD2a and LPHD2b was also distinctly increased in hyper-alpha-lipoproteinemia; it was decreased in hypo-alpha-lipoproteinemia, while the LPHD3 content was slightly altered in blood plasma. The capacity of LPHD to transfer of CS appears to increase in hyper-alpha-lipoproteinemia and to decrease in hypo-alpha-lipoproteinemia. As shown by correlation analysis, metabolism of LPHD3 occurred independently from the other LPHD subfractions.

The value of kdiss of the "proteinkinase-cAMP" complex was increased 1.8-fold, number of the nucleotide binding sites was increased 3.7-fold with simultaneous decrease in cAMP concentration, when the cyclase system was studied in skeletal muscles of mice with experimental thyrotoxic myopathy. Activities of phosphodiesterase, adenylate cyclase, rate of activation of adenylate cyclase by adrenaline and sodium fluoride did not significantly differ as compared with normal values. Impairment of hormonal regulation of the cAMP-dependent processes is apparently responsible for multiple molecular and structural injuries in skeletal muscles in thyrotoxicosis.

A new subclass of high density lipoproteins designated as HLD2c was found in the human blood plasma of newborn by analytic ultracentrifugation in the flotation rate interval Fo1,20 8.0--12.0. HDL2c was isolated from the total HDL fraction of newborn by preparative ultracentrifugation at the density 1.071.

Rabbit mesenteric lymph contained all the main classes of lipoproteins detected in plasma: chylomicrons (CM), very low density lipoproteins (VLDL), low density lipoproteins (LDL), high density lipoproteins (HDL). The main classes of lipoproteins in lymph were CM and VLDL, whereas LDL and HDL were the main lipoproteins in blood plasma. The heaviest subfractions HDL3 were not observed in mesenteric lymph. Lymph contained only low amount of LDL; molecular mass of lymphatic LDL was lower as compared with the blood plasma lipoproteins. Mesenteric lymph lipoproteins were enriched with triglycerides and contained less cholesterol, phospholipids and protein than the corresponding blood plasma lipoproteins. As distinct from blood plasma lipoproteins, apo E and apoproteins of low molecular mass (apo C?) were not found in lymphatic lipoproteins. Content of Apo-I was much higher in lymphatic VLDL as compared with the blood plasma VLDL. The dissimilarity in patterns and composition between blood plasma and lymphatic lipoproteins indicated that the latter were derived from intestine. Thus, intestine was able to produce CM, VLDL, HDL2 and apparently a small amount of LDL.

Native and modified horse LPHD (methylated, succinylated, with blocked Arg-residues and COOH-groups) were administered intravenously (400 mg by protein) into healthy rabbits and into animals with hypercholesterolemia. Concentration of the modified LPHD decreased much more distinct in blood plasma of healthy rabbits as compared with native LPHD. The same results were obtained in rabbits with hypercholesterolemia after administration of methylated and succinylated LPHD. The higher rate of elimination of the modified LPHD appears to occur due to their phagocytosis by macrophages. The data obtained suggest that catabolism of LPHD in rabbits, contrary to LPLD catabolism, did not involve specific cell receptors.

Lipoprotein complexes were studied in intact parts of human aorta as well as in areas of aorta impaired with atherosclerosis. The arterial walls contained particles, which were similar to pre-beta and beta-lipoproteins as evidenced by immunological properties and by size. At the same time, lipoproteins of the vascular walls differed distinctly from those of blood serum because these former lipoproteins possesed altered electrophoretic mobilities in acetyl cellulose, contained glycosamineglycans, exhibited lower rate of flotation in salt-free solution as compared with the salt-containing solution under conditions of analytical ultracentrifugation. The data obtained suggest that the lipoproteins formed complexes with glycosamineglucans in vascular walls.

The mean cholesterol content in erythrocytes of patients, which are not impaired by hepatic diseases is 1.26 +/- 0.02 X 10-13 g/cell and it is not depended on the plasma cholesterol level.