1 Department of Respiratory Medicine, Hakodate Goryoukaku Hospital, 38-3 Goryoukaku-cho, Hakodate-shi, Hokkaido 040-8611, Japan and Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan.
2 Department of Respiratory Medicine, Hakodate Goryoukaku Hospital, 38-3 Goryoukaku-cho, Hakodate-shi, Hokkaido 040-8611, Japan.
3 Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan.