1. Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, Sapporo 001-0021, Japan
2. Department of Advanced Clinical Glycobiology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo 001-0021, Japan
3. Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan
4. Faculty of Science, Ochanomizu University, Bunkyo-ku, Tokyo 112-0860, Japan