1. Department of Surgery, National Taiwan University Hospital, Taipei, 100, Taiwan. Tel.: ext 5080; Fax: ; E-mail: cshuang@ha.mc.ntu.edu.tw
2. Institute of Biomedical Sciences, Academia Sinica, Taipei, 115, Taiwan. Tel.: ; Fax: ; E-mail: bmcys@ccvax.sinica.edu.tw