Received: 14 November 2019
Accepted: 23 December 2019
First Online: 24 January 2020
Compliance with ethical standards
: The authors declare that they have no conflicts of interest.
: This study was approved by the institutional ethical committees of National Defense Medical College (No. 2914) and Nagoya University (No. 2011-1248-7). All procedures were performed in accordance with the Declaration of Helsinki and its later amendments.
: A written informed consent was obtained from each subject participating in the study.