1. Department of Orthopedic Surgery, Nihon University School of Medicine, Tokyo, Japan.
2. Division of Cell Regeneration and Transplantation, Department of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan.
3. Department of Pediatrics, Nihon University School of Medicine, Tokyo, Japan.
4. Laboratory of Cell and Tissue Biology, College of Bioresource Science, Nihon University, Fujisawa, Japan.