1. Department of Medical Technology, Kagawa Prefectural University of Health Sciences, 281-1, Hara, Mure-cho, Takamatsu 761-0123, Kagawa, Japan
2. Department of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki-cho 761-0793, Kagawa, Japan