1. Laboratory of Veterinary Pathophysiology and Animal Health, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
2. School of Nursing, Ibaraki Christian University, 6-11-1 Omika, Hitachi, Ibaraki 319-1295, Japan
3. Graduate School of Nursing, Ibaraki Christian University, 6-11-1 Omika, Hitachi, Ibaraki 319-1295, Japan