1. Department of Neurosurgery (IS), School of Medicine, Kyorin University, Tokyo
2. Department of Neurosurgery (TA), Saitama Medical Center School, Kawagoe
3. Department of Neurosurgery (KS), Fuji Brain Institute Hospital, Shizuoka
4. Department of Neurosurgery (KT), Tokyo Women's Medical College, Tokyo
5. Department of Neurosurgery (HA), School of Medicine, Hokkaido University, Sapporo
6. Department of Neurosurgery (TY), School of Medicine, Tohoku University, Sendai
7. Department of Neurosurgery (HK), National Cardiovascular Center, Osaka
8. Department of Neurosurgery (TO), Osaka Medical College, Osaka
9. Department of Physiological Chemistry (SI), School of Medicine, Hiroshima University, Hiroshima, Japan