Affiliation: | (1) Department of Neurosurgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-0006, Japan e-mail: shingo4@igaku.md.tsukuba.ac.jp Tel.: +11-81-298-53-3167 Fax: +11-81-298-53-3214, JP;(2) National Institute of Bioscience and Human Technology, Agency of Industrial Science and Technology, Tsukuba, Ibaraki, Japan, JP |