[The study of intratumoral PO2 in brain tumors]

The aim of this study was to evaluate the hypoxic cells in the human brain tumor in vivo. Untreated 16 cases of brain tumor were analysed. During the surgery for the purpose of removal of the tumor, needle type-O2 sensors were inserted into femoral artery and in brain tumor to measure PaO2 and intratumoral O2 pressure. A plate type O2 sensor was put on the surface of surrounding brain cortex to measure cortical O2 pressure. These O2 sensors for this study is able to measure O2 pressure continuously and to observe these three O2 pressure simultaneously. Operations were performed endotracheal anesthesia under inhalation of ethrane with maintaining systolic blood pressure 120 mmHg. Setting the rate of O2 and N2O gas inhalation 1/3, PaO2 revealed about 110 mmHg which is similar value as physiological state--1 ATM, air inhalation--. The value of TuO2 and BrO2 were revealed 15.3 +/- 2.3 (mean +/- SE) mmHg and 59.8 +/- 6.5 (mean +/- SE) mmHg. According to these results, it might be said that hypoxic fraction surely exist intratumoral tissue. It is also well known that O2 removes from higher pressure zone to lower pressure zone after O2 was diffused from red blood cell in brain tissue. It might be also mentioned that much lower hypoxic fraction than the value of this study is existing intratumoral tissue. It has long been recognized that hypoxia influences the response of cells and tissues to radiation. However, they have been suspected on the basis of experimental data in vitro. This study showed hypoxic fraction in human brain tumor tissue in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)