1. Pathology Department, Kashima Laboratory, Nonclinical Research Center, LSI Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan
2. Current affiliation: Pathology Department, Kashima Laboratories, LSIM Safety institute Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan