[The effect of membrane-active compounds on the radiation-modifying effect of glucose in x-irradiated ascitic tumor cells]. / Vliianie membranoaktivnykh soedinenii na radiomodifitsiruiushchii éffekt gliukozy pri rentgenovskom obluchenii kletok astsitnoi opukholi.

A study was made of the influence of membrane-active agents with different mechanisms of action (quercetin, amiloride, valinomycin, and digitonin), that modify the transmembrane transfer of inorganic ions, on a modifying effect of a glucose loading in X-irradiated Ehrlich ascites tumor cells. The combination of digitonin with glucose increased the damaging effect of radiation on tumor cells by 1.8-2.2 times as compared to glucose alone. Merely insignificant changes in the radiation-modifying effect of glucose were observed when it was combined with other membrane-active agents.

[Interphase death of dividing cells. Relation of the death of cultured Chinese hamster fibroblasts to the inter- and extracellular pH]. / Issledovanie interfaznoi gibeli deliashchikhsia kletok. Zavisimost' gibeli kul'tiviruemykh fibroblastov kitaiskogo khomiachka ot pH vnutri i vne kletki.

In studying interphase death (ID) of dividing cells from Chinese hamster fibroblast culture a differently directed relationship between ID rate and pH has been shown: the ID rate increases with pH increasing from 6.6 to 8.1 and decreases with pH from 5.0 to 6.6. The dependence is the same as that observed with lymphoid cells. With radiation doses increasing from 100 to 600 Gy and pH defined, the ID rate increases.

[The interphase death of dividing cells. The relation of interphase death to cell energy requirements]. / Issledovanie interfaznoi gibeli deliashchikhsia kletok. Zavisimost' interfaznoi gibeli ot énergoobespecheniia kletki.

In experiments with irradiated cells of Chinese hamster and Ehrlich ascites tumor a study was made of the influence of energy provision on their interphase death rate. The presence of the uncoupler of respiration and oxidative phosphorylation--carbonyl cyanide-3-chlorophenylhydrazone--in a medium without glucose was shown to drastically increase the interphase death rate of cells of both types, whereas this effect was not observed in a medium with glucose.

[Spatial and temporal heterogeneity of pH values in lysosomes from different types of cells cultured in situ]. / Prostranstvennaia i vremennaia neodnorodnost' lizosom razlichnykh tipov kul'tiviruemykh kletok in situ po velichine pH.

Distinct variety of the pH value, at the ranges of pH 4.5-7.0, was found in lysosomes. Small lysosomes exhibited lower pH values as compared with large organelles. These lysosomes were measured in cultures of normal cells (hamster fibroblasts, pig embryonal kidney cells, primary culture of chicken embryonal fibroblasts) and of tumoral cells (neurinoma of rat trigeminal ganglion). Studies of individual lysosomes demonstrated that temporal alterations in the pH value reached up to 1.5 un of the pH period 15-45 min. Distinct space-temporal heterogeneity of the cellular lysosomal apparatus in the pH value enabled to create optimal conditions for enzymatic systems catalyzing hydrolysis of various macromolecules. The mean values of pH were very similar in all the cultivated cells studied, within ranges of pH 5.5-5.8, which appears to depend on the similarity of functions of the lysosomal apparatus in the cells of various classes.

[Effect of a pH change in the medium and cytoplasm of cultured cells on the rhythm of protein synthesis]. / Vliianie izmeneniia pH v srede i tsitoplazme kul'tiviruemykh kletok na ritm sinteza belka.

A circahoral rhythm of protein syntheses similar to that in monolayer hepatocytes was discovered in cell culture of Chinese hamster fibroblasts. Studies on the effects of pH changes in the culture medium and cultured cells on different parameters of protein synthesis showed some pH-dependent changes of predecessor pool and of its incorporation intensity into proteins. At the same time changes in a relative incorporation of the predecessor into proteins (with a correction for the pool) were insignificant. This value characterizing the productivity of protein synthesis does not seem to be directly associated with pH changes in the cells. The mean period of the rhythm of protein synthesis and intracellular pH was not changed with medium pH alterations.

[Change in cellular pH in hyperthermia and hypoxia]. / Izmenenie pH kletok pri gipertermii i gipoksii.

Change of pH of cultivated cells (Chinese hamster fibroblasts and pig embryonic kidney cells) was studied during their incubation under oxygenation conditions and at different temperatures using microfluorimetry with fluorescein diacetate. It was shown that pHc was 7.0 at temperatures 22-37 degrees C. Hyperthermia and hypoxia resulted in cell acidity. The effect was enhanced with an increase in the period of exposure to both agents. Intracellular pH more acid values were noted in the effect of hyperthermia in the presence of hypoxia or exogenous pH acid values. The authors made a conclusion of the importance of a degree of acidity of the intracellular medium for the survival of cells irradiated under hyperthermia conditions.

[Post-irradiation modification of radiation damage to cells. Increase in reproductive death during post-irradiation reduction of cellular pH]. / Postradiatsionnaia modifikatsiia luchevogo porazheniia kletok. Usilenie reproduktivnoi gibeli pri postradiatsionnom snizhenii pH kletok.

The effect of enhancement of reproductive death in postradiation reduction of intracellular pH(pHk) was studied on Chinese hamster hypoxic cells. It was shown that pHk reduction up to 6.0 for 1 h enhanced the radiation damaging effect. The maximum effect was observed in pHk reduction shortly after irradiation. The dependence of the effect on the interval between irradiation and subsequent pHk reduction was different under various conditions of postradiation incubation: in good oxygenation due to fast reparation of potential injuries the effect of pHk reduction sharply decreased with time; the effect of additional influence of pHk reduction was insignificant against a background of low survival of cells incubated after radiation under hypoxic conditions. It was assumed that low survival under postradiation hypoxic conditions was determined by pHk reduction shown in this study during cell incubation under hypoxic conditions.

[The effect of post-radiation hypoxia on potential cell injury]. / O vliianii postradiatsionnoi gipoksii na potentsial'nye povrezhdeniia kletok.

The effect is described of increasing the reproductive death of pro- and eucaryotes by the action of a short-term (approximately 60 min) acute hypoxia after a single irradiation thereof in normal culture medium at the logarithmic phase of growth. The effect observed is probably associated with the fact that potential damages are poorly repaired and are fixed under hypoxic conditions.

[Radiomodifying effect of glucose load on oxygenated and hypoxic tumor cells]. / Radiomodifitsiruiushchee deistvie gliukoznoi nagruzki na oksigenirovannye i gipoksicheskie opukholevye kletki.

A study was made of the radiomodifying effect of the glucose load on the oxygenated and hypoxic cells of Ehrlich's ascites carcinoma (EAC) in vitro. It has been shown that EAC cells actively utilize glucose causing a decrease in pH cell suspensions. Under hypoxia conditions it was slightly more pronounced than under oxygenation conditions (up to 5.2 and 5.6 respectively). The incubation of EAC cells with glucose prior to and after irradiation under hypoxia conditions enhances, to a great extent, their radiation injury: effect modifying factor (EMF) exceeds 3.5. The volume of the modification with the glucose load of the lethal effect of irradiation on EAC cells varies with EMF from 1.1. to 1.5.

[Fibroblast adhesion to glass and the dynamics of pH change in the medium in the pericellular space]. / Adgeziia fibroblastov k steklu i dinamika izmeneniia pH sredy v okolokletochnoi oblasti.

A study was made of dynamics of pH changes in the pericellular space of the Chinese hamster fibroblasts after the completion of cell sedimentation in three media. With the first medium, the cells were spread over the glass, with the second one they were attached to the glass without spreading and with the third medium the cells were not attached to the glass at all. The pH value of the medium surrounding the cells decreased, mainly, within the first 6 hours after sedimentation was completed, this depended on the cell population density on the glass surface. The outlook of this dependence was different for the three media. Based on the analysis of the results obtained it is concluded that the attachment of cells to glass may lead to the increased efflux of acid metabolic products from the cell.

[Change in the pH of Chinese hamster cells following irradiation with different doses]. / Izmenenie pH kletok kitaiskogo khomiachka posle oblucheniia v raznykh dozakh.

Changes in the intracellular pH cf Chinese hamster cells irradiated with different doses were investigated. Using the fluorescence method it was shown that irradiation of cultured cells with doses inducing reproductive death (2.5-20 Gy) caused a temporary shift of pH by 0.4-0.5 units toward the alkaline region. After a dose of 500 Gy, inducing interphase death of cells, the alkalization of the intracellular medium was more pronounced (greater than or equal to 8.0) and persisted for 1.5 h.

[pH dynamics in the lysosomes and cytoplasm of tissue culture cells measured intravitally using the indicator dye neutral red]. / Dinamika pH v lizosomakh i tsitoplazme kletok kul'tury tkanei pri prizhiznennom izmerenii s pomosch'iu indikatornogo krasitelia neitral'nogo krasnogo.

A method of pH determination in the cytoplasm and individual lysosomes of intact living cultured cells is proposed using an indicator dye--neutral red (NR). The pH value of an investigated structure stained with NR is from the ratio between its optical densities at two wave lengths, the one corresponding to the isobestic point (lambda = 470 nm), and the other--to the absorption maximum of the neutral form of the dye (lambda = 450 nm). This method enabled us to make pH determination in the range from 4.5 to 7.2; the accuracy of the method reaches +/- 0.36 at pH 4.7 and diminishes to +/- 0.16 at pH much greater than 5.5. Using this method for the culture of pig kidney embryonal cells and Chinese hamster fibroblasts a heterogeneity of lysosomes was found with respect to the average pH value, oscillating ultradian changes in intralysosomal pH values, and the relationship between the changes and the size and average pH values of lysosomes. It is shown that the accumulation of NR in lysosomes depends on the pH gradient between lysosomes and the cytoplasm, which diminishes with the development of non specific cell response under the influence of some agents) high NR concentrations, inhibitor of glycolysis, or uncouplers of oxidative phosphorus lotion).