Funding for this research was provided by:
Grant-in-Aid for Scientific Research (17K1158)
Received: 5 June 2019
Revised: 12 October 2019
Accepted: 21 October 2019
First Online: 27 November 2019
Ethics approval and consent to participate
: The study was approved by the Ethics Review Board of Kansai Medical University (No.0617) in accordance with the ethical guidelines of the Helsinki Declaration of 1975. All specimens were collected and used with informed consent from the volunteer donors.
: Not applicable.
: The authors declare that they have no competing interests.