[Polyradiomodification. The efficacy of the postradiation use of hyperglycemia and hyperthermia in treating tumors of different sizes]. / Poliradiomodifikatsiia. Effektivnost' postradiatsionnogo primeneniia giperglikemii i gipertermii pri lechenii opukholei raznoi velichiny.

The paper is concerned with comparative assessment of the effectiveness of the separate and combined postradiation use of induced hyperglycemia (IH) and local hyperthermia (HT) with respect to tumor size in experiments on mice with transplantable Ehrlich carcinoma. The antitumor effect of these modalities was estimated by the criteria of the duration of tumor growth inhibition and cure of animals. The combined use of IH and HT significantly enhanced antitumor action of prior irradiation and resulted in improved therapeutic results for medium- and large-size tumors as compared to small ones. The authors discussed probable causes of enhancing the effectiveness of IH and HT with tumor growth, as a result of changes in pH, blood supply and other tumor characteristics.

[Hyperglycemia as a means of increasing the efficacy of hyperthermia in radiotherapy of tumors]. / Giperglikemiia kak sredstvo povysheniia éffektivnosti gipertermii pri luchevoi terapii opukholei.

In experiments on mice with Ehrlich carcinoma transplanted into the thigh the authors determined a gain in tumor heating from the use of induced hyperglycemia (IH) during thermoradiotherapy. Tumors were irradiated at a dose of 20 Gy followed in 3 h by local hyperthermia (HT) by emerging a tumor into water at 40-45 degrees C for 30 min. IH followed irradiation (i.e. 3 h before HT) in the form of 5-time ip administration of glucose at a total dose of 10.4 g/kg for 2 h. Isoeffective tumor damage was achieved in irradiation combined with HT (45 degrees C) only and in irradiation with subsequent IH and HT (40 degrees C), i.e. a gain in the temperature of heated water as a result of glucose use was 5 degrees C. In the independent use (without irradiation) of HT this value was equal approximately 2.5 degrees C. Thermometric investigations have shown that these effects are partially accounted for by better heating (by 0.2-0.4 degrees C) of tumor tissue in IH. However glucose action was mainly connected with resultant physiological changes in tumors like a noticeable decrease in pH and stable disorder of the blood flow.

[Polyradiomodification. Optimization of the combined use of hyperglycemia and local hyperthermia in tumor irradiation]. / Poliradiomodifikatsiia. Optimizatsiia sochetannogo primeneniia giperglikemii i lokal'noi gipertermii pri obluchenii opukholei.

Therapeutic potentialities of various types of polyradiomodification were compared in experiments on mice with solid Ehrlich carcinoma by using separate and combined use of short-term hyperglycemia (SH) and local hyperthermia (HT). In the combination of modifiers SH was always created 3 h after the beginning of glucose administration. Irradiation of tumors was performed in either of 5 moments: 4 h or immediately before SH, in-between SH and HT, 30 min. or 2.5 h after SH. Two control schemes, in which irradiation was combined with one of the modifiers only, corresponded to each polyradiomodification regimen. The combined use of SH and HT produced a more noticeable effect than their separate action. A maximum effect on a tumor was observed in the combined use of both modalities shortly after irradiation, and it was not accompanied by enhanced skin radiation injury in a tumor growth zone. Irradiation after or in-between SH and TH resulted in enhanced skin radiation reactions. Thus, the highest therapeutic effect was noted in those schemes of polyradiomodification in which SH and HT followed radiation treatment. SH and HT induced suppression of the blood supply in tumors played an important role in the optimization of the combined use of SH and HT with irradiation.

[The role of a decrease in pH in enhancing the antitumor action of ionizing radiation with the aid of hyperglycemia]. / Rol' snizheniia pH v usilenii protivoopukholevogo deistviia ioniziruiushchego izlucheniia s pomoshch'iu giperglikemii.

The role of a pH decrease in glucose-enhanced antitumor action of prior irradiation was investigated in experiments on mice with Ehrlich solid carcinoma. For this purpose changes in pH and the blood flow as well as the modification of a tumor radiation effect caused by glucose and weakly metabolizing galactose injected in similar regimens, were compared in parallel groups. It was shown that in both regimens glucose and galactose injections resulted in approximately the same reduction of a blood flow rate in tumors, however a pH decrease after the use of glucose was much greater, and glucose-enhanced antitumor radiation action was more noticeable. A conclusion has been made that a pH decrease in tumors is a major factor determining the efficacy of glucose as a radiomodifier.