Abstract
AIM: To investigate pathological effects of internal radiation on human body, we have determined radioactivity on samples of Nagasaki acute atomic bomb casualties. Alpha particle forms in the paraffin-embedded specimen were detected by a classical method of autoradiography. We have already reported that the presence of a genomic instability, 53BP1-focus formation, in the atomic bomb survivors as a predisposition to cancer. 53BP1 rapidly forms nuclear foci at the sites of DNA double strand breaks. The much 53BP1-focus expression was observed in the cells surrounding Thorotrast granule of liver. In this study, we determine 53BP1-focus formation on tissue specimens. The much expression of 53BP1-focus was also observed on the liver of Nagasaki atomic bomb acute casualties, who was outdoor 0.5km from the bomb hypocenter. Hyposensitivity to radiation induced apoptosis was observed in liver, kidney and lung. In this study we investigated radiation induced DNA damage response and autophage. Autophage involves the sequestration of cytosolic proteins and organelles within double-membrane structures termen autophagosomes and their subsequent degradation via lysosomal hydrases.
MATERIAL and METHODS: 1)Rats were exposured 8Gy by X ray. The liver, kidney and lung specimen were prepared after 3,6 and 24 hours and determined 53BP1 and LC3 by immunohistochemistry, and autophage by electron microscope. 2) The liver specimen from Thorotrast patient were studied. RESULTS: 1) 53BP1-focus expression, LC3 expression and autophage by electron microscope were observed in the rat liver, . 2) The much 53BP1-focus expression and LC3 expression were observed in the cells surrounding Thorotrast granule of liver. These suggested internal radiation exposure triggers DNA double strand brake and forms 53BP1-focus. The much expression of 53BP1-focus was also observed on the spleen of Nagasaki atomic bomb acute casualties, who was outdoor 0.5km from the bomb hypocenter and died at 68th day. and spleen. These suggested internal radiation exposure triggers damage response and autophage.
