Author contributions
All authors had access to the data and a role in writing this
manuscript. The authors fulfill the ICMJE Criteria for Authorship.
Yoshihiro Nakamura wrote the initial draft. Kazuhiro Asada, Masashi
Toyama, and Yoshiro Fujita reviewed the manuscript and provided critical
intellectual input. All authors read and approved the submitted draft of
the manuscript.
Acknowledgements: We thank Dr Waka Kokuryo for making
constructive comments and for providing encouragement.