1. Department of Anatomy, Faculty of Health Sciences; Kyorin University; Tokyo Japan
2. Sakai Electron Microscopy Application Laboratory; Saitama Japan
3. Department of Physiology; Iwate Medical University School of Dentistry; Iwate Japan
4. Department of Anatomy Faculty of Medicine; Kyorin Unversity; Tokyo Japan
5. Department of Anatomy; Kawasaki Medical School; Okayama Japan