1. Department of Anatomy and Embryology, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan;
2. Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology, Open Space Laboratory, Tsukuba, Ibaraki, Japan; and
3. School of Medical Sciences, and
4. Department of Surgery, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan