1. Department of Otolaryngology, Head and Neck Surgery, Shizuoka City Shizuoka Hospital, Shizuoka, Shizuoka 420-8630, Japan
2. Department of Pathology, Shizuoka City Shizuoka Hospital, Shizuoka, Shizuoka 420-8630, Japan
3. Department of Otolaryngology, Shin-Suma General Hospital, Kobe, Hyogo 654-0048, Japan
4. Department of Physiology, Kurume University School of Medicine, 67 Asahi-Machi, Kurume 830-0011, Japan