1. Department of Otolaryngology, Fukushima Medical University, Fukushima, Japan;
2. Department of Otolaryngology, Head and Neck Surgery, Kyoto University, Kyoto, Japan;
3. Division of Animal Sciences, National Institute of Agrobiological Sciences, Ibaraki, Japan;
4. Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan