Ⅱ. Ultrastructural changes of cells

Different characteristic damages of cells after heating and radiation were studied by electron mictroscopy.The visible damages,such as the enlarged mitochondria,increasing amout of lysosmes and perichromatin granules could be shown 1 hours after heating at 43℃ for 30 min,but no visible changes were shown until 36 hours following radiation（500 rad）.
Using a new method of the ultrastructural study on selected mitotic cells after hyperthermia and radiation by the first time the ultrastructural changes of chromosome and spindle were observed.We have found loosen structure of chromosome and disappearance of microtubles at 1 hour following hyperthermia,but at the same time no apparent abnormalities were observed after radiarion.It may be the main reason for division delay in heat injured cells.After radiation,the giant cells and abnormal morphologic changes of cells were gradually increasing.Division of a few giant cells was observed.