[Effect of carbon dioxide on free radical processes as affected by artificial hypobiosis in rats]. / Vliianie uglekisloty na svobodnoradikal'nye protsessy v usloviiakh iskusstvennogo gipobioza u krys.

High CO2 concentrations in the inspired air have been studied for their effect on the free-radical oxidation of lipids in the lipids in the blood, its serum and mitochondria of the rat liver under artificial hypobiosis. Kinetics of free-radical oxidation of lipids was estimated from the changes in chemiluminescence parameters as well as the content of products which react with thiobarbituric acid. It is found that in animals in the state of artificial hypobiosis the intensity of free-radical oxidation of lipids was rather less as compared with animals which did not fall into hypobiosis because of the exclusion of CO2 from the inspired air. The data obtained permit concluding that the increase of CO2 concentration in the inspired air prevents from the development of the oxidative stress. It is evident that the increase of CO2 in the inspired air occurs before the formation of the adaptational mechanisms, directed to the preventing of lesion of membrane lipids under artificial hypobiosis.

[Effect of N-palmitoylethanolamine on energy-dependent transport of Ca2+ in vesicles of myometrium sarcolemma and their phospholipid composition]. / Vliianie n-pal'mitoilétanolamina na énergozavisimyi transport Ca2+ v vezikulakh sarkolemmy miometriia i ikh fosfolipidnyi sostav.

N-palmitoylethanolamine (NPE) was studied for their effect on calcium pump of pig myometrium sarcolemma. NPE in concentration of 10 microM, stimulated by 28-46% Mg2+, ATP-dependent accumulation of Ca2+ in vesicles of plasmatic membrane of uterus myocytes taking absolutely no effect on passive release of this cation from them. NPE modified phospholipid composition of sarcolemma, causing the increase of percentage content of phosphatidylinositol (by 20.2%) and lysophosphatidylcholine (2.7 times). While NPE effects transport Ca2+, Mg(2+)-ATPase solubilized from plasmatic membrane and purified due to the method of affinity chromatography on calmodulin-sepharose 4B, no activating effect of NPE on the calcium pump was observed. And what is more, a weakly expressed tendency to inhibition (by 14-15%, respectively) of the rate of Ca2+, Mg(2+)-dependent enzymic hydrolysis of ATP has been revealed. It is supposed that the effect of NPE on active transmembrane transport of Ca2+ is an important link in the general mechanism of contraction-relax of the myometrium and is, apparently, connected with its modifying effect on the lipid composition of the sarcolemma.

[Effect of n-palmitoylethanolamine on energy-dependent transport of Ca2+ in intracellular structures of myometrium and their phospholipid composition]. / Vliianie n-pal'mitoilétanolamina na énergozavisimyi transport Ca2+ vo vnutrikletochnykh strukturakh miometriia i ikh fosfolipidnyi sostav.

N-palmitoylethanolamine (NPE) was studied for its effect on the systems of energy-dependent transport of Ca2+ in the intracell structures (mitochondria, endoplasmic reticulum) of permeabilized cells of smooth muscles of the rat uterus as well as on the lipid composition of myocytes. NPE in concentration of 10(-5) M partially (by 30-50%) inhibited energy-dependent accumulation of Ca2+ in endoplasmic reticulum and mitochondria of myometrium cells permeabilized by means of treatment of myocytes suspension by digitonin (0.1 mg/ml). NPE modifies the lipid composition of permeabilized myocytes when determining the increase of the amount of inorganic phosphorus of total phospholipids by 57.3% at the expense of considerable accumulation of phosphatidylcholine, phosphatidylethanolamine and sphingomyelin. It is supposed that the effect of NPE on the systems of energy-dependent transport of Ca2+ is achieved through the modification of phospholipid composition of a cell, while modulating effect of NPE on the active transmembrane transfer of Ca2+ in the intracellular structure can be an important link in the general mechanism of the effect of this compound on Ca2+ metabolism in myometrium and on Ca(2+)-depended control of the contracting function of the uterus.

[The characteristics of lectin binding to the surface of differentiated neuroblastoma C 1300 cells]. / Osobennosti sviazyvaniia nekotorykh lektinov s poverkhnost'iu differentsirovannykh kletok neiroblastomy C 1300.

Peculiarities of the binding of lectins of castor bean, cochlea, soya bean, lime bean and wheat germs to the surface of differential neuroblastoma C 1300 N 18 cells have been studied using the method electron cytochemistry. It is found that the quantity of the bound lectin conjugates with colloidal gold on the surface of differentiated cells varied considerably from that on the surface of nondifferentiated cells.

[Morphological differentiation and change in the lipid composition of neuroblastoma C1300 cells treated with gangliosides]. / Morfologicheskaia differentsirovka i izmenenie sostava lipidov kletok neiroblastomy C1300 pod vliianiem gangliozidov.

The effect of exogenous gangliosides on the morphological differentiation of neuroblastoma 1300 N18 cells was studied Simultaneously the content of gangliosides and lipid composition of the cells was investigated. Gangliosides were shown to increase the quantity of cells with long neurites. This effect depended on the dose of gangliosides. The addition of 50 and 100 micrograms of gangliosides per 4 ml of serum-free culture medium increased the quantity of cells with neurites by 38 and 63.4%, respectively. The level of morphological differentiation in cells cultivated with gangliosides was higher than in cells incubated with 5'-bromodeoxyuridine. Noticeable quantities of lysophosphatidylcholine (absent in the control) appeared in ganglioside-treated cells and the level of cholesterol increased. The amount of other lipid compounds in cells differentiated in the presence of gangliosides was similar, but not identical to the quantity of lipid compounds in cells differentiated by 5'-bromodeoxyuridine and by the serum-free medium.

Changes in lipid composition of neuroblastoma C1300 N18 cell during differentiation.

Phospholipids and cholesterol were found to be the main lipids in mature and immature neuroblastoma cells. The ratios for the total cholesterol/phospholipids in these undifferentiated and differentiated cells were 0.33 and 0.52, respectively. The ratios of 0.45 and 0.62 were obtained with corresponding plasma membrane fractions. Individual fatty acid contents in the loosely bound lipid fraction were higher than in tightly bound lipids. The total levels of saturated fatty acids increased in both of these fractions. While arachidonic acid content significantly decreased, it increased simultaneously (600%) in the free fatty acid fraction during differentiation. The amount of cholesterol esters increased three-fold as a result of maturation. For the first time it was possible to detect, in neuroblastoma cells, several lipids, namely N-acylphosphatidylethanolamine, N-acylethanolamine and semilysobisphosphatidic acid. They all changed during maturation. Total N-acylphosphatidylethanolamine content decreased by 50%, disappearing completely from membrane fractions. N-Acylethanolamine disappeared from the cell as well as from membrane fractions. On the other hand the total cellular content of semilysobisphosphatidic acid increased without any alterations in its membrane content. Functional implications of our investigations are discussed.

[Detection of N-acylethanolamine phospholipids in neuroblastoma C1300 cells]. / Obnaruzhenie N-atsilétanolaminovykh fosfolipidov v kletkakh neiroblastomy C1300.

Phospholipids with high chromatographic mobility are detected in cells of murine neuroblastoma C 1300. One of them is identified (proceeding from data of successive chemical degradation) as N-acylphosphatidylethanolamine. It may be a precursor of physiologically active N-acylethanolamines. N-palmitoyl and N-stearoylethanolamines are shown to inhibit the transport of ions through the veratrine-activated fast sodium channels as well as remove the effect of lysophospholipids accumulation in cells under the effect of veratrine.

[Transmembrane lipid transport between lecithin liposomes and neuroblastoma C1300 N18 cells]. / Transmembrannyi transport lipidov mezhdu letsitinovymi liposomami i kletkami neiroblastomy C1300 N18.

The method of double isotopic labels was used to study dynamics of lipid metabolism between neuroblastoma C 1300 N 18 A 1 cells and lecithin liposomes which contained 4.5-5 mumol of lecithin in 1 ml of the suspension. The cell lipids were labelled by radioactive carbon and cultivated on the medium with [1-14C] sodium acetate, phosphatidylcholine of liposomes was labelled by tritium. It is shown that 15-30 min long incubation with liposomes causes a sharp decrease of the cholesterol esters amount with a simultaneous fall of the free cholesterol level. The total content of phospholipids in this case remains unchanged though there occurs the noticeable exchange of labelled phospholipids between cells and liposomes. The cholesterol content in the plasma membranes of cells lowers sharply. The neuroblastoma cells are able to compensate arising changes in the cholesterol level for 45-60 min after which they progressively die. 90 min later only an insignificant part of the population (about 10% of cells) is retained.

[Modification of the lipid composition of neuroblastoma C1300 cells using liposomes]. / Modifikatsiia lipidnogo sostava kletok neiroblastomy C1300 s pomoshch'iu liposom.

An essential increase in the total cholesterol content with a significant growth in the level of its esters was observed in neuroblastoma C1300 cells differentiated by means of 5'-bromodesoxyuridine and incubated for 1 h with lecithin-cholesterol liposomes (1:1 mol/mol). These cells also displayed an increased amount of polyunsaturated fatty acids in the composition of lecithin molecules and the appearance of lysolicethin as well. Incubation of the cells with lecithin liposomes was accompanied by a decrease in the content of cholincholesterol in the cells. In this case the level of cholesterol esters decreased to a greater extent than the level of free cholesterol. In lecithin molecules of these cells there occurred a relative increase of saturated fatty acids. The cells can retain viability and compensate changes caused by cholesterol excess during their incubation with lecithin-cholesterol liposome for 60-90 min. A longer incubation with liposomes results in a sharp drop of cell viability.

[Relation between the functional characteristics of fast sodium channels and lipid composition of neuroblastoma C1300 cells]. / Zavisimost' funktsional'nykh kharakteristik bystrykh natrievykh kanalov ot lipidnogo sostava kletok neiroblastomy C1300.

The paper deals with functional characteristics of fast sodium channels modified by liposomes of differentiated neuroblastoma cells. Cells with a 60% increased total cholesterol content were used. The cells were found to contain lysolecithin. In lecithin the amount of polyunsaturated fatty acids was enhanced. It is established that veratrin added to the culture medium of cholesterol-enriched cells increased the rate of 86Rb release to a greater extent than in the control cells. When studying the temperature dependence of veratrin-activated transport of Rb+ in the intact and lecithin-cholesterol-lyposomes-modified cells it was shown that the veratrin-activated Rb+ release is more sensitive to temperature fluctuations than nonactivated one. In this case it is higher in lecithin-cholesterol-lyposomes-modified cells than in intact ones.

[Changes in the lipid composition of murine neuroblastoma C 1300 cells during the process of differentiation]. / Izmenenie lipidnogo sostava kletok neiroblastomy myshi C 1300 v protsesse differentsirovki.

The paper deals with the lipid composition of nondifferentiated cells at the logarithmic and stationary growth phases as well as with differentiated cells of C 1300 neuroblastoma adopted to the Eagle medium. It is shown that phospholipids and cholesterol dominate at the studied growth phases among lipids. Their amount in the differentiation process is thrice as high calculating per cells. The quantity of individual phospholipids changes in different manner during differentiation. The phosphatidylinosite level is higher than of other substances.

[Transport of Rb+ via activated sodium channels of clone N 18 phi 1 neuroblastoma cells]. / Transport Rb+ cherez aktivirovannye natrievye kanaly kletok neiroblastomy klona N 18 fi 1.

A study was made of the Rb+ transport via activated sodium channels of clone N 18 phi 1 neuroblastoma cells cultured in the Eagle medium with 10% bovine serum. The time of population doubling was about 10 h. The cell differentiation was induced by adding bromdeoxyuridine in a concentration of 1-4 10(-5) M. The cells contained 172 +/- 12 and 340 +/- 35 micrograms of protein per 10(6) cells at the logarithmic growth phase and in differentiated state, respectively. It is shown that veratrin produced a 1.3-fold increase in the rate of 86Rb+ removal from undifferentiated cells and 2.5-fold increase in that from differentiated cells. Tetrodotoxin removed completely the effect of veratrin. A conclusion is made on the presence of a new clone of fast sodium channels in cell membranes.