1. Department of Internal Medicine, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Toubetsu, Hokkaido 061-0293, Japan
2. Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan
3. Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan