[1] Wake Forest Univ, Med Ctr, Dept Dermatol, Sch Med, Winston Salem, NC 27157 USA
[2] Wake Forest Univ, Med Ctr, Dept Neurobiol & Anat, Sch Med, Winston Salem, NC 27157 USA
[3] Wake Forest Univ, Med Ctr, Dept Regenerat Med, Sch Med, Winston Salem, NC 27157 USA
[4] Natl Univ Singapore, Yong Loo Lin Sch Med, Biostat Unit, Singapore 117548, Singapore