Unique characteristics of radiation-induced apoptosis in the postnatally developing small intestine and colon of mice - Imaoka, T.; Kakinuma, S.; Kaminishi, M.; Miyoshi-Imamura, T.; Murakami-Murofushi, K.; Nishimura, M.; Nishimura, Y.; Okamoto, M.; Shimada, Y.; Takabatake, T.