[Effect of metronidazole and local irradiation of the tumor on paramagnetic metal complexes of the liver and tumor tissues]. / Vliianie metronidazola i lokal'nogo oblucheniia opukholi na paramagnitnye metallokompleksy tkanei pecheni i opukholi.

A study was made of changes in the intensity of the ESR signals in tissues of sarcoma-37 and liver of mice after radiation of the tumor, administration of metronidazole, and after the combined effect of the two factors. The most pronounced changes in the ESR signals were induced by metronidazole. An appreciable increase in the content of nitrosyl complexes in the tumor was noted after the combined effect of metronidazole and radiation which was indicative of the radiation-induced formation of a large number of metronidazole anion-radicals in the tumor.

[Combined effect of metronidazole, interferon synthesis inducers and DNA repair inhibitors]. / Sovmestnoe deistvie metronidazola, induktorov sinteza interferona i ingibitorov reparatsii DNK.

In experiments on mice with solid sarcoma 37, a study was made of modification of the radiosensitizing effect of metronidazole. The increase in the leucotic interferon titre, induced by the interferon synthesis inductors, did not influence the radiosensitizing efficiency of metronidazole: after the administration of the repair inhibitor, 8-bromocaffeine, the coefficient of suppression of tumor growth was higher and the number of mice with the regressed tumors greater as compared to animals affected by metronidazole and radiation.

[Radiosensitizing effect of interferon synthesis inducers]. / Radiosensibiliziruiushchee deistvie induktorov sinteza interferona.

The preinjection of inductors of leukocytic interferon synthesis of rapid (poly I.poly C, dextransulfate) and slow (tyloron) types to mice bearing inoculated solid sarcoma 37 considerably increases the efficiency of X-irradiation of tumors: the coefficient of tumor growth inhibition (kappa *) exceeds 1.0, and the number of animals with the completely regressed tumors increases. The effectiveness of the procedure depends on the time of the injection of the preparations and modes of irradiation.

[Oxygen status and angioarchitectonics of different types of tumors and their changes after radiotherapy]. / Kislorodnyi status i angioarkhitektonika opukholei razlichnykh tipov i ikh izmenenie pri luchevoi terapii.

The study of the oxygen tension and blood supply to the implanted tumors of different histological structures demonstrated a correlation between pO2 and blood supply of sarcoma 37 after a single and fractionated irradiation. As to Lewis carcinoma and B-16 melanoma, the correlation was only found in tumors of a small size: as the tumor grew up to 14-15 mm such a correlation was absent. It was also established that the radiation-induced changes in the vessels and the oxygenation depended upon the histological structure of the tumor.

[Oxygen status of transplantable murine tumors and its change during radiotherapy]. / Kislorodnyi status perevivnykh opukholei myshei i ego izmenenie pri luchevoi terapii.

The degree of oxygenation in sarcoma 37, Lewis' carcinoma and melanoma B-16 of mice has been shown to depend on a tumor type (the most marked degree in sarcoma 37), it decreases from the periphery and with tumor growth. In single and fractionated irradiation the oxygen tension increases considerably in large size tumors and in the central zones of small size tumors. In melanoma B-16 reoxygenation is insignificant. It is assumed that the oxygen status plays an important role in the radiation response of large size tumors only.

[Universal approaches to the control of tissue radiosensitivity during radiation therapy of malignant tumors]. / Universal'nye podkhody k upravleniiu tkanevoi radiochuvstvitel'nost'iu pri luchevoi terapii zlokachestvennykh opukholei

Approaches to the problem of the control over tissue radiosusceptibility, united by the common purpose--a need for selective increase of the intact tissues tolerance to overcome tumor hypoxia, are discussed. Such universal approaches include an application of radiation characterized by high linear wastes of radiation energy, methods of increased oxygenation of tumors, the use of electron sink compounds, and irradiation under conditions of hypoxia--hypoxiradiotherapy. The experiments conducted by the author and his collaborators with local irradiation of a number of transplantable mice tumors under general hypoxia, produced by inhalation of oxygen poor gaseous mixtures (5% O2+95% N2), have shown not only a selective protection of normal tissues, but also greater regression of tumors. The mechanism of the observed phenomenon is being suggested, and some prospects of hypoxiradiotherapy in the oncological clinic are discussed.