This study was supported by Siriraj Research Development
Fund, Faculty of Medicine Siriraj Hospital, Mahidol University,
Bangkok, Thailand.
Contributors: S. Chearskul took responsibility for the
study concept and design, collection and analysis of the
data, and writing the manuscript. W. Nitiyanant took a
response on clinical aspects of studied patients. W. Kriengsinyos,
S. Sangurai, S. Kooptiwut, S. Onreabroi, M. Churintaraphan
and N. Semprasert provided their skillful technical
assistance.