1 Department of Gastroenterology, Nagano Red Cross Hospital, Nagano, Japan.
2 Department of Internal Medicine, Division of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan.
3 Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
4 Department of Metabolic Regulation, Shinshu University School of Medicine, Matsumoto, Japan.
5 Research Center for Social Systems, Shinshu University, Matsumoto, Japan.