OXYGENATION OF THE RAT-9L GLIOSARCOMA AND THE RAT-13672 MAMMARY-CARCINOMA WITH VARIOUS DOSES OF A HEMOGLOBIN SOLUTION

Tumor oxygen tensions were measured using a computer controlled pO(2) microelectrode in two preclinical solid tumor models, the rat 9L glios arcoma and the rat 13672 mammary carcinoma. Tumor oxygenation profiles were determined under four conditions: 1) normal air breathing, 2) ca rbogen (95% O-2/5% CO2) breathing, 3) after intravenous administration of a solution of ultrapurified polymerized bovine hemoglobin with nor mal air breathing and 4) after intravenous administration of a solutio n of ultrapurified polymerized bovine hemoglobin with carbogen breathi ng. Both tumors had severely hypoxic regions under normal air breathin g conditions. Although carbogen breathing increased the oxygenation of the better oxygenated portions of the tumor, it did not impact on the severely hypoxic tumor regions. Administration of the hemoglobin solu tion was effective in increasing the oxygenation throughout both tumor s under normal air breathing conditions. The addition of carbogen brea thing to administration of the hemoglobin solution eliminated severe h ypoxia in the 9L gliosarcoma and markedly reduced the severely hypoxic regions of the 13672 mammary carcinoma.