抄録
The detecting ability of the photon counting system of single photoelectron counting method has been greatly improved and an equipment of this method, designed for biochemical and biomedical applications, was developed. The photomultiplier used in the instrument was of bialkali photocathode of 5cm diameter with the spectral responce nearly from 300nm to 660nm and of specifically low noise selected from hundreds of the same photomultipliers. The photomultiplier was cooled down to -20° in the equipment in the actual photon counting for the further reduction of the noise. All other possible electrical noises from the inside and the outside of the counting machine were eliminated or minimized. The sensitivity of the photon counting equipment reached the level high enough to permit the determination of extremely weak light emission like those of human blood and tissue samples. Thus, the first quantitative measurement, to our knowledge, of ultra weak chemiluminescence of human blood samples was performed with this instrument. The whole blood and plasma samples of normal subjects gave relatively low levels of light emission. On the contrary, the blood samples of patients with diabetes mellitus and with liver diseases showed significantly higher light emission levels. Of particular interest was of the blood of patients with obstructive jaundice and of severe hepatitis. The light emission of the blood samples of these disease was generally very high and in the levels allowing the spectral analysis of the emitted light.
The analysis and the scavenger experiments indicated the contribution of singlet oxygen as the photon emitting entity in these blood samples.
