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The review highlights the membrane aspect of cholesterol efflux from cell membranes to high density lipoproteins (HDL), an initial stage of reverse cholesterol transport to liver. In addition to traditional viewpoints considering cholesterol transport as the step of sequential lipoprotein transformation, which involves blood plasma apoproteins and proteins transporters, employment of proteomic approaches has shown the active role of cell plasma membranes as cholesterol donors and plasma membrane bound proteins in cholesterol transport. These include ATP-binding ABC-A1 transporter and membrane receptor SR-B1. There is experimental and clinical evidence that impairment of genes encoding these proteins cause impairments of reverse cholesterol transport (e.g. Tangier disease and genetic manipulations with experimental animals.) Although precise mechanism involving these membrane proteins remains unknown it is suggested that ABC-AI with free plasma apoA1 facilitates the efflux of membrane phospholipids and formation of their complex with apoAI. This complex accepts membrane cholesterol, with simultaneous formation of a full HDL particle. In certain cells there is correlation between cholesterol efflux into HDL and expression of SR-BI, which reversibly binds to HDL. This receptor protein may influence molecular organization of membrane phospholipids and cholesterol, facilitating cholesterol efflux. The review also deals with properties of ABC-A1 and SR-B1, putative mechanisms of their effects, the role of these proteins in reverse cholesterol transport and their functional coupling to the phospholipid matrix of biomembranes.

There is increasing evidence that different phospholipids are involved in regulation of various cell processes and cell-cell interactions. Lysophospholipids (lysophosphatidic acid, lysophosphatidylcholine) and a number of lysosphingolipids play particular roles in these regulations. Their effects are mediated by specific G-protein-coupled receptors. G-Protein coupled signal transduction to the cell nucleus involving a chain of intracellular protein kinases induces the main effects in cells--growth, proliferation, survival, or apoptosis. This review summarizes recent data on various groups of lysophospholipid receptors and their cell signal transduction pathways.

This review considers various functional aspects of cell sphingolipids (sphingomyelin, ceramides) and lysosphingolipids (sphingosine-1-phosphate (S1P) and sphingosine phosphorylcholine). Good evidence now exists that they are actively involved in numerous cell-signaling processes. The enzymes responsible for formation and interconversion of cell sphingolipids (sphingomyelinases, ceramidase, sphingosine kinase, S1P-lyase) exhibit high sensitivity to various stimulating factors. This determines the content of individual cell sphingolipids and therefore the mode of cell response. Special attention is paid to preferential localization of sphingolipids in the rigid plasma membrane domains (rafts) coupled to many signal proteins. The suggestion is discussed that ceramide signaling may be based on the modification of fine molecular interactions in lipid rafts, resulting in its clusterization inducing the signal transduction. The review also highlights involvement of sphingolipids in cell proliferation, apoptosis, and in processes implicated to atherosclerosis.

Therapeutic effect of corn oil was studied in rabbits with alimentary atherosclerosis. Corn oil was administered (2 ml/kg, 30 days) after the completion of cholesterol diet unlike studies, where they were administered simultaneously. Total cholesterol, apoB-lipoprotein cholesterol and triglycerides decreased more intensively in rabbits fed by corn oil than in control group. No changes in high-density lipoprotein cholesterol were observed. The most pronounced effect was noted in aorta morphological analysis: an aorta damage degree was 4.8% as compared with 52.9% in the control group. The results show that available plant oils with omega-6 polyunsaturated fatty acids (PUFA), in particular corn oil, may as well as omega-3 PUFA be used as the base for antiatherogenic preparations.

Basing on the data of Bouissou et al. on an increase of cholesterol content in the skin biopsies in atherosclerosis patients, the cholesterol amount was evaluated after superficial atraumatic rapid treatment of patients palm skin. The optimization of the extraction conditions was performed: the surface skin cholesterol value was constant for individual subjects (variability factor 5%). The range of this value was 1.5-6 Mg/cm2 and it was higher for atherosclerotic patients. No correlations with any conventional plasma lipoprotein parameters were observed. At the same time positive correlation (r = 0.54. p < 0.01) was observed with dyslipoprotein coefficient--(Ch+TG/alpha-Ch). Possible diagnostic significance of this skin cholesterol parameter is discussed.

Using the methods of surface balance we compared surface activity of different natural phosphatidylcholines. Dipalmitoylphosphatidylcholine, the principal component of natural surfactant, is characterized by less rapid spreading on the air-water interface compared to unsaturated yolk and soybean phosphatidylcholines, while the absolute rate of surface tension reduction was the same for all test lecithines. The surface activity of modified saturated soybean phosphadtidylcholine (Phospholipon) was similar to that of dipalmitoylphosphatidylcholine. The relationship between saturation of fatty acids in the molecule of phosphatidylcholine and the time of spreading on the air-water interface revealed in this study allows to use this parameter together with equilibrium surface tension for evaluation of surface activity when testing synthetic surfactant constituents.

Using the methods of surface balance we compared the effects of different phosphatidylcholines and synthetic surfactant Exosurf on the equilibrium surface tension at the air-water interface. It was found that dipalmitoyl-lecithin, the principal component of natural surfactant, and its synthetic substitutes can be replaced by other phosphatidylcholines, in particular, by modified soybean phosphatidylcholine phospholipon. It was demonstrated that equilibrium surface tension is an informative characteristic in the assessment of potential components for synthetic surfactants.

The effect of droperidol, a butyrophenone derivative, on the food reflex to electrical stimulation of the hypothalamic food center was studied in experiments on freely moving rabbits. Intravenous injection of droperidol (0.3 mg/kg) lowered the threshold of the evoked food response. Inhibitory influences of the anterior neocortical zones on food responses were absent but facilitatory influences of the caudal regions of the cortex were preserved or even somewhat increased. The effects observed can be explained by the dopamine-negative action of droperidol and by disturbance of the brain inhibitory system.

A polarographic method is suggested and can be recommended as a simple device for measuring the rates of oxidation of steroid hormones and xenobiotics. The rate of hydroxylation of steroids depends, it is suggested, on the polarity of the molecule of the oxidation substrate.