[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.

[Evolution of subpopulations of cells of transplantable tumors following x-ray irradiation]. / Evoliutsiia subpopuliatsii kletok perevivaemykh opukholei posle rentgenovskogo oblucheniia.

The paper is devoted to a study of the structure of subpopulations of 3 experimental tumors (ascitic Ehrlich carcinoma, melanoma B-16 and Lewis lung adenocarcinoma) in their progression and following single local X-radiation. At the same time some functional indices of cell viability were investigated over time: intracellular pH, intensity of respiration, the level of cell protein, the level of lipid peroxidation (according to the content of one of its end-products--malonic dialdehyde). Considerable differences of subpopulations within one tumor and between different tumor types were established. The relationship of functional differences of these subpopulations with the clonogenicity of forming cells was shown. X-radiation caused inhomogeneous changes in the structure of subpopulations, the above indices changed. The authors have analyzed the regularity of these changes, their relationship with radiosensitivity or radioresistance of tumor cell subpopulations.

[Dynamic changes in the pH and potassium concentration in a suspension of ascitic tumor cells under glucose load]. / Dinamika izmenenii pH i kontsentratsii kaliia v suspenzii kletok astsitnoi opukholi pri gliukoznoi nagruzke.

A single addition of glucose to 10% (6 v/v) suspension of the Ehrlich ascite tumor cells results in biphasic changes of pH and potassium ion concentration in the extracellular medium during 120 minutes. Phases of pH and potassium changing do not coincide. Increasing glucose amount from 100 to 400 mumol/10 ml suspension causes no marked modification of ion dynamics. Possible mechanisms of the above phenomena and their relation to cell power are discussed.

[Fractionated irradiation of Ehrlich carcinoma using fast neutrons]. / Fraktsionirovannoe obluchenie kartsinomy Erlikha bystrymi neitronami.

Ehrlich's carcinoma growth inhibition was studied under the conditions of fractionated irradiation with fast neutrons and x-rays. Fast neutrons were obtained from a reaction of 13.6 MeV alpha----Be on the Y-120 cyclotron. Neutron beam irradiation doses were within 2-17 Gy, x-ray doses from 7.5 to 72 Gy. Tumors were subjected to local irradiation with 1-8 fractions at a 3-4 day interval. The results showed that an increase in the total duration of a course of irradiation and a decrease in a dose per fraction resulted in a reduced effect of carcinoma growth inhibition. At the same time, an increase in the fast neutron RBE under these conditions from 3.4 (in single irradiation) to 5.4 (in 8-fold irradiation) indicated more pronounced inhibition of reparation and/or repopulation in a tumor in neutron beam irradiation.

[Repair of chromosome damage in human lymphocytes after fractionated irradiation with fast neutrons]. / Reparatsiia povrezhdenii khromosom limfotsitov cheloveka pri fraktsionirovannom obluchenii bystrymi neitronami.

The frequency of chromosome aberrations in nonstimulated lymphocytes of the peripheral human blood was shown to change after fractionated neutron irradiation of mean energy of 6.0 MeV. At a 2-hour interval between exposures, the number of aberrations exceeded, and at 5-6-hour interval was less than that induced by a single exposure at the same dose.

[Principle of neutron teletherapy with the Soviet U-120 cyclotron]. / Obespechenie distantsionnoi neitronnoi terapii na otechestvennom tsiklotrone U-140.

The authors present the results of their clinical developments on fast neutron irradiation of malignant tumors on the low-flow cyclotron U-120. The technique involved design of complexes provided with the sources of fast neutrons based on beryllium, gas deuterium and beryllium-deuterium targets. The spectrometry and dosimetry measurements of collimated bunches of fast neutrons have shown that the mean energies of neutrons from beryllium and gas deuterium targets are 6.0 and 11.5 MeV, while the absorbed doses are 0.8 and 0.5 sGy/min X microA. The increase of the local power of the biological dose inside the phantom irradiated by the collimated bunch of fast neutrons is shown to be due to intermediate energy neutrons, the contribution of which to the spectrum of fast neutrons increases with the decrease of their mean energy. The problems of selection of the sources of fast neutrons for neutron therapy are discussed.

[Experience with neutron teletherapy of malignant tumors]. / Opyt distantsionnoi neitronnoi terapii zlokachestvennykh opukholei.

A medico-biological complex for fast neutron therapy of cancer and research in physics and radiobiology was developed at the Siberian Branch of the Center within the framework of Cyclotron Department of Research Institute of Nuclear Physics (Polytechnical Institute, Tomsk). Certain problems of forming a fast neutron beam from the Y-120 type cyclotron are discussed. Baseline data of dosimetric and radiobiologic studies are presented. The first experience of Soviet researchers with fast neutron treatment of head and neck cancer is described. Favorable preliminary results suggest further clinical application of the said procedure.

[Comparative effectiveness of metronidazole, hyperglycemia and hyperthermia in irradiation of Ehrlich carcinoma with fast neutrons]. / Sravnitel'naia éffektivnost' metronidazola, giperglikemii i gipertermii pri obluchenii kartsinomy Erlikha bystrymi neitronami.

A study was made of a possibility of the modification of the effects of fast neutrons (with the mean energy of about 6 MeV.) by local hyperthermia (HT), short-term induced hyperglycemia (STIH) and metronidazole (MZ). The study was conducted in vivo on intramuscularly transplantable ascitic mouse Ehrlich's carcinoma. The dose-effect relationship built up in different time after the day of irradiation, was considered in parallel with the time course of tumor growth; regression curves were obtained using computer. Using the value of 50% tumor growth inhibition and the ratio of areas under the model dose-effect curves as criteria of a degree of modification the authors have come to a conclusion that HT possesses the most noticeable intensifying effect.

[Radiosensitivity of resting and proliferating cells irradiated with fast neutrons]. / O radiochuvstvitel'nosti pokoiashchikhsia i proliferiruiushchikh kletok pri obluchenii bystrymi neitronami.

The influence of 6 MeV neutrons on the duration of the cell cycle and DNA biosynthesis was studied in rat regenerating liver cells irradiated at G0-(resting cells) and G1-stages (proliferating cells). It was demonstrated that neutron irradiation of the proliferating cells caused deeper changes both in the duration of the cell cycle and in inhibition level of DNA biosynthesis, than irradiation of the resting cells.

[Effect of hydrocortisone and insulin on changes of oxidative phosphorylation after neutron irradiation]. / O deistvii gidrokortizona i insulina na izmeneniia okislitel'nogo fosforilirovaniia posle neitronnogo oblucheniia.

Total double irradiation of rats with a fast neutron flow does not affect oxidative phosphorylation in the liver mitochondria but causes an essential decrease in the intensity of phosphorylation in mitochondria and chemoluminescence in blood serum of animals. Postradiation multiple administration of hydrocortisone intensifies the radiation inhibition of oxidation and phosphorylation of mitochondria and insulin administration stimulates phosphorylation in the liver mitochondria and the intensity of chemoluminescence in blood serum of rats. Hydrocortisone in combination with insulin has a less pronounced stimulating effect on phosphorylation than insulin, but the intensity of chemoluminescence in this case is higher than under the effect of each preparation separately.

[Effect of insulin on oxidative phosphorylation in the liver and heart mitochondria of adrenalectomized rats]. / Vliianie ubsykuba ba ijuskutek'noe fosforilirovanie v mitokhondriiiakh pecheni i serdtsa adrenalektomirovannykh krys.

The effect of insulin was studied as applied to the inhibited under conditions of adrenalectomy process of oxidative phosphorylation in the rat liver and heart mitochondria. It is established that adrenalectomy does not change oxidative activity of mitochondria but inhibits the process of phosphorylation, which results in the decreased values of the ADP/O coefficient and the respiratory control. Insulin administered to the adrenalectomized rats 3h before the experiments reduces the disturbed oxidative phosphorylation in mitochondria of the liver and heart by intensifying the degree of ADP phosphorylation.