[The microenvironment of tumor cells and the antitumor effect of hyperthermia].

Intravenous infusion of 20% solution of glucose (80 mg/kg of body mass per 1 min) resulted in considerable changes in microenvironment of tumor cells: by the 90th-120th min of infusion there was a decrease in pH, pO2, blood flow inhibition, an increase in the relative number of cells in the S-phase of the mitotic cycle in a tumor. There was no increase in tumor ATP and glucose up to the values at which these substance could enhance thermoresistance, a situation being rather favorable for realizing a damaging effect of hyperthermia. The use of hyperglycemia in the above regimen prior to MWF-hyperthermia enhanced 2-3 times its antitumor effect on the model of subcutaneously transplanted Guéren carcinoma and Pliss lymphosarcoma.

[Hydrogen ion concentration in tumor issue and artificial hyperglycemia].

A series of articles concerned with determination of pH in the tumour and with studies of pH changes under induced hyperglycemia are reviewed. Based on the available data the following conclusions are drawn: pH in the tumour tissue is lower than in the initial normal or surrounding tissues by 0.5 units on the average; the optimal pH value is more acidic; alkalosis in the tumour-bearing organism is a hypercompensatory reaction of the host as a result of advanced tumour in which pH is dropped; the induced hyperglycemia promotes a pronounced decrease of pH in the tumour, pH of the normal tissues being unchanged; the possibility to decrease pH in the tumour should be taken into account when developing new methods of the antitumour therapy.

[Antitumor action of thiophosphamide against a background of glucose modification of the tumor cell mitotic cycle and a decrease in intratumor pH].

The scheme of thiophosphamide injections on the background of glucose infusion intravenously has been employed. It was shown that thiophosphamide injections at the moment of the increased quantity of tumor cells in G2-phase, in the transition G1 leads to S of the cell cycle ad hyperacidity of tumor tissue enhanced significantly the therapeutic effects. The complete tumor regression was noted in 60% of cases.

[Activation of tumor tissue glycolysis by inorganic phosphate at low pH values].

It was shown that the activating effect of inorganic phosphorus on glucose utilization by the tumour tissue in vitro was retained at low pH of the incubation medium. The 0.15M Na2HPO4 in tris-buffer solutions infusion at the moment of cessation of the tumour selfacidity under glucose infusion led to further decrease of the tumour tissue pH.