[1] Massachusetts Gen Hosp, Brigham & Womens Hosp, Harvard Affiliated Emergency Med Residency, Dept Emergency Med, Boston, MA 02116 USA
[2] Univ Cape Town, Div Emergency Med, ZA-7925 Cape Town, South Africa
[3] Univ Stellenbosch, ZA-7600 Stellenbosch, South Africa
[4] Univ So Calif, Dept Biochem & Mol Biol, Los Angeles, CA USA