1. Department of Urology, Viet Duc University Hospital, Hanoi, Vietnam.
2. Department of Urology, Seoul Medical Center, Seoul, Korea.
3. Department of Physiology, Advanced Urogenital Diseases Research Center, Chung-Ang University College of Medicine, Seoul, Korea.
4. Department of Urology, Advanced Urogenital Diseases Research Center, Chung-Ang University College of Medicine, Seoul, Korea.