1 United Memorial Medical Center (Araiza, Duran, Varon), Houston, Tex.; Universidad Autónoma de Baja California (Araiza), Tijuana, México; Universidad Xochicalco (Duran), Ensenada, México; The University of Houston School of Medicine (Varon), Houston, Tex.
2 United Memorial Medical Center (Araiza, Duran, Varon), Houston, Tex.; Universidad Autónoma de Baja California (Araiza), Tijuana, México; Universidad Xochicalco (Duran), Ensenada, México; The University of Houston School of Medicine (Varon), Houston, Tex. jvaron@uh.edu.