1. Department of Infectious Diseases, Internal Medicine, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
2. Department of Otolaryngology, Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
3. Department of Plastic and Reconstructive Surgery, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan