[Effect of lipid hydroperoxides on the yield of chromosome aberrations in irradiated cells].

The combined effect of linoleic acid hydroperoxide and gamma-radiation on Ehrlich ascites tumor cells was not additive with regard to the formation of chromosome aberrations. When cells were preincubated in the presence of a subliminal hydroperoxide dose of 2.10(-5) M the number of aberrant cells increased after irradiation.

[Correlation of the membrane and genetic effects of lipid peroxidation].

Linoleic acid hydroperoxides delivered to Ehrlich ascites tumor cells in vitro in a concentration reaching a threshold one (approximately 10(-5) M) sharply decrease their ionic permeability and the value of membrane capacity. With suprathreshold hydroperoxide concentrations (greater than 10(-5) M), the specific yield of chromosome aberrations and the share of aberrant cells increase while the mitotic index decreases. The correlation between general regularities and the equality of the threshold concentrations, with a reference to membrane and genetic effects of hydroperoxides, is thought to be an indication of a close relationship between membrane lesions caused by the development of induced lipid peroxidation and injury to genetic apparatus of the cell.

[Damage of cell membranes by linoleic acid hydroperoxide].

It has been shown on Ehrlich ascite carcinoma cells that under the effect of linoleic acid hydroperoxides in vitro ionic permeability and membrane capacity of the cells sharply decrease after some threshold concentration of hydroperoxides (greater than 10(-5) M), while the threshold value decreases with the increase of the time of cell incubation in the presence of hydroperoxides. Interrelationship between the development of induced POL processes in the cell membranes and disturbance of their functional-structural state in the living cell is discussed.

[Relation of K+-dependent cellular swelling to the state of cellular membranes].

It has been shown that after heating of ACE cells for 15 min at temperature 46 degrees C inhibition of K+-dependent swelling and a sharp decrease of cell resistance and capacity are observed. Changes of the parameters studied were of a threshold pattern, the threshold temperature proved to be uniform and equaled 46 degrees C. It is believed that the temperature relationships obtained point to an important role of barrier functions of cellular membranes in K+-dependent cell swelling.

[Dose relationship of the electric conductivity of liver cells at early periods after gamma-radiation].

The dependence of electroconductivity and electric capacity of isolated liver cells, irradiated in vitro, upon radiation dose (within 100 Gy) was described by an extreme curve characterized by the presence of a "critical" dose (25 Gy) at which the effect was maximum. The kinetics of changes in the electric parameters, which were measured at early times following irradiation (up to 4 h), has an opposite direction. The possibility is discussed that peroxidation and repair processes in membrane lipids are involved in the effects observed.

[Fe2+ ion effect on Ehrlich ascites tumor cell conductivity and ion permeability].

It is shown that incubation of EAT cells in the presence of Fe2+ ions caused the threshold decrease of active and capacitance constituents of cell suspension impedance and rate of ion efflux from cells to the isotonic sucrose media, and decrease extent rose with an increase of Fe2+ ion concentration and temperature. A discrepancy between the results described and experimental model system data is discussed.

[K+-dependent swelling of Ehrlich ascitic carcinoma cells in the presence of linoleic acid hydroperoxides and Fe2+ ions].

EFfect of linoleic acid hydroperoxide (I) and Fe++ on viscous elastic properties of cell membranes of Ehrlich ascite carcinoma was studied by the method of K+-dependent swelling. It has been shown that the action of 1 and Fe++ is of similar character, and the effect depends on the incubation time and concentration of agents in the incubation mineral solutions. After 2 h incubation the concentration relationships have two patterns characterized by increased swelling at concentrations 10(-6)-10(-5) M and inhibition of this process at concentrations above 10(-5) M.

[Complex effect of K+ ions and viability inhibitors of tumor cells].

It is shown that NaCN, actinomycin D and sarcolysin damaged EAT cells, and the level of cell damage depended on K+ concentration in the incubation salt solution and the injury agent. With respect to NaCN the cell sensitivity was found to rise to a great extent when the cells were incubated in the presence of 143 mM K+. For actinomycin D and sarcolysin the effect of K+ ions was negligible.

[Temperature phase transitions in cancer cells].

Light scattering (90 degrees) of Ehrlich ascites tumor and sarcoma 37 cell suspension in the temperature range 25-60 degrees C was studied (heating velocity was 3 grad/min). It is found that the scattering curve has the peak at 46 degrees C and two plots which are typical of phase transitions in the membranes; the first plot in the range 40-46 degrees C is reversible and the second one at 46-51 degrees C is irreversible. It is proposed that 46 degrees is a critical temperature for the membranes structure stability and viability of the studied cells.

[Letter: Mechanism of K+-dependent swelling of Ehrlich ascites carcinoma cells].

Limiting values of cell volume measured under the conditions of K+-dependent swelling of EAC cells decrease when the medium is hypertonized, the extent of the decrease depending more on the type of the agent applied than on the concentration gradient. According to the action efficiency the agents studied can be placed in the following sequence: Ca2+, succrose Na+,K+. It is concluded that Ca ions strengthen the cell membrane, while K+ ions produce a contrary effect.