Lysophospholipid receptors in cell signaling.

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.

[Phosphatidylcholine as the basis for artificial pulmonary surfactants: comparison of surface active properties]. / Fosfatidilkholiny kak osnova iskusstvennogo legochnogo surfaktanta: sravnenie poverkhnostno-aktivnykh svoistv.

The Wilhelmy balance was used for in vitro testing of surface active properties of natural phosphatidylcholines (PCs) as possible basis for surfactant replacement therapy. Saturated PC, dipalmitoylphosphatidylcholine (DPPC) and phospholipon (PL) had similar parameters of surface activity: minimal values of equilibrium surface tension (EST) and the longest surface spreading time (SST). Unsaturated egg and soybean PCs also shared similar values of surface activity parameters (EST and SST). Correlation between fatty acid saturation of PCs and EST or SST allows to consider both these parameters as informative ones for surface tension evaluation in the search of components for artificial surfactant. Since parameters of DPPC and PL surface activity are equivalent in their performance, they may be potentially employed for testing instead of DPPC as a possible base for artificial surfactant.

[Erythrocyte cholesterol content in polycythemia vera: relation to ischemic heart disease]. / Soderzhanie kholesterina v éritrotsitakh pri istinnoi politsitemii: sviaz' s ishemicheskoi bolezn'iu serdtsa.

Relative cholesterol content and its distribution between erythrocytes and plasma were studied in 34 patients with polycythemia vera (PV) both with and without concomitant coronary heart disease (CHD). Deformability of erythrocytes, disturbances of microcirculation (blood flow fragmentation, decrease of capillary density) were also assessed. Erythrocytes cholesterol/phospholipids molar ratios (0.68+/-0.03) in patients was lower than normal value (0.8) in spite of decreased cell deformability. This was associated with some increase of peroxidation products. Blood cholesterol distribution between cell and plasma species had some peculiarities caused by high hematocrit: compared with normal value erythrocytes of patients carried relatively larger portion of total blood cholesterol (23.7+/-0.8% and 27-31%, respectively). However in CHD patients these values were significantly lower with correspondent increase of plasma cholesterol quota. This allowed to suggest possible protective role of blood cholesterol redistribution in polycythemia patients, through erythrocytes trafficking of some part of plasma cholesterol.

[Characteristics of the lipid transport system in psoriasis]. / Osobennosti lipid-transportnoi sistemy pri psoriaze.

Cholesterol of high density lipoprotein (HDL) subfractions (HDL2 and HDL3), activity of cholesterol ester transport protein (CETP), and standard lipoprotein parameters (cholesterol, triglycerides, HDL cholesterol) were measured in plasma of 192 patients with various psoriasis forms, which included simple "distributed psoriasis", erythrodermic and arthropathic psoriasis. Among psoriatic patients unusually high percent of persons with both hypo- and hyper-cholesterolemia was observed. The same situation was observed with frequency of cases with both low and high plasma HDL cholesterol levels, the distribution being depending from disease severity. In contrast to norm, psoriasis patients had big range not only in HDL2 cholesterol level, but also in HDL3 cholesterol. They also had decreased CETP activity. Data obtained suggest the existence of changes in reverse cholesterol transport system in psoriasis, which may influence skin cell proliferation (via control of cell supply with cholesterol).

Comparison of distribution characteristics of phosphatidylcholines and surfactant preparation.

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.

[The antiatherogenic action of plant oils with added omega-3 polyunsaturated fatty acids]. / Antiaterogennoe deistvie rastitel'nykh masel s dobavkoi omega-3 polinenasyshchennykh zhirnykh kislot.

Quick model of experimental atherosclerosis--3 weeks of cholesterol feeding and 3 weeks of standard diet for aorta atheromatosis development--was used in rabbits. Then one group of animals was fed 1 month by plant oil of specific composition, with added omega-3 (linolenic) fatty acid, and the other group received the same dose of fish oil. The most intensive decrease of plasma cholesterol and erythrocyte cholesterol/phospholipid ratio was in rabbits, that received the oil with linolenic acid. Triglyceride level decreased gradually in all animal groups in the same degree, and HOL cholesterol did not change. After the end of experiment the aorta damage degree in group, that received plant oil with linolenic acid, was only 10.8%, as compared with 36.2% in control group (without treatment) and 39.3% in rabbits, that received fish oil. The absence of fish oil effect supports the earlier data about rabbits specific sensitivity to this product resulting in possible hepatotoxic effect. The data indicates on the usefulness of rabbit model in fish oil effects investigations, and also on the positive, antiatherogenic effect of plant oil with added linolenic acid.

[Possible approaches to creating phospholipid preparations--acceptors of membrane cholesterol]. / Vozmozhnye podkhody k sozdaniiu fosfolipidnykh preparatov--aktseptorov membrannogo kholesterina.

The capability of liposomes with plant phosphatidylcholine to extract cholesterol from erythrocyte membrane was investigated. It was shown, that plant phosphatidylcholine extracted 42% of membrane cholesterol, without causing haemolysis. This cholesterol extraction was responsible for the decrease of membrane microviscosity and for the increase of Na+, K+-ATPase activity. It is suggested that it is possible to create the extractive agent of cholesterol with plant phosphatidylcholine.

[The use of a generalized biochemical parameter for the evaluation of the effectiveness of hemosorption in patients with mechanical jaundice of calculous etiology]. / Primenenie obobshchennogo biokhimicheskogo parametra dlia otsenki éffektivnosti gemosorbtsii u bol'nykh s mekhanicheskoi zheltukhoi kal'kuleznogo geneza.

Quantitative methods for evaluation of impairments in the functional state of liver tissue by means of a generalized biochemical index enabled to evaluate efficiency of hemosorption as compared with other methods of preoperative treatment of patients with mechanical jaundice of calculous genesis. Hemosorption was found to contribute most effectively to restoration of the liver tissue functional state decreasing the risk of acute liver tissue insufficiency during the postoperational period.

[Determination of free serum phenol by gas-liquid chromatography in hemosorption]. / Opredelenie svobodnogo fenola v syvorotke krovi metodom gazozhidkostnoi khromatografii pri gemosorptsii.

A modified procedure is developed for estimation of free phenol in blood serum by means of gas-liquid chromatography, appropriate in clinico-biochemical assays. The method enabled to evacuate the blood serum free phenol in healthy persons as well as in various pathologies of abdominal cavity before and after hemosorption. After hemosorption a distinct decrease of the free phenol content was observed in blood, correlating with improved clinico-biochemical patterns of the patients, with a decrease in encephalopathy manifestations as well as with normalization of the neurological status.