1. Department of Pathology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093–0612, USA.
2. Department of Anesthesiology, University of California, San Diego, La Jolla, CA 92093, USA.
3. Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Chiba, 260-8677 Japan.