1. Department of Otolaryngology, Asan Medical Center and University of Ulsan College of Medicine, Seoul 138-736, Korea.
2. Department of Otolaryngology, Kangwon National University College of Medicine, Chuncheon 200-701, Korea.
3. Department of Physiology, Asan Medical Center and University of Ulsan College of Medicine, Seoul 138-736, Korea.
4. Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan 614-735, Korea.