1. Division of Urology, Department of Surgery, Taichung Veterans General Hospital, Taichung 407;
2. Division of Urology, Department of Surgery, Tri-Service General Hospital, Taipei 100;
3. Department of Biology and Anatomy, National Defense Medical Center, Taipei 100, Taiwan, Republic of China; and
4. Department of Pharmacology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261