2Department of General Internal Medicine and Clinical Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan
*Correspondence Takechiyo Yamada Department of Otorhinolaryngology, Head and Neck Surgery, Akita University, Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
Tel.: +81-188-84-6171, Fax: +81-188-36-2622, e-mail:ymdtkcy@gmail.com