1. Pathology Department, Kashima Laboratory, Nonclinical Research Center, Mitsubishi Chemical Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan
2. Pathology Department, Kumamoto Laboratory, Nonclinical Research Center, Mitsubishi Chemical Medience Corporation, 1285 Kurisaki, Uto, Kumamoto 869-0425, Japan
3. Department of Pathology, Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotouge, Hirakata, Osaka573-0101, Japan