1. Division in Anatomy and Developmental Biology, Department of Oral Biology, Research Center for Orofacial Hard Tissue Regeneration, Oral Science Research Center, College of Dentistry, Brain Korea 21 project for Medical Science, Yonsei Center of Biotechnology, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea; and
2. Department of Oral Anatomy, School of Dentistry, Iwate Medical University, 1-3-27 Chuo-dori, Morioka city, Iwate 090-8505, Japan;