[1] Washington Univ, Dept Biomed Engn, St Louis, MO 63110 USA
[2] Washington Univ, Sch Med, Dept Orthoped Surg, St Louis, MO 63110 USA
[3] Shriners Hosp Children St Louis, St Louis, MO USA
[4] Washington Univ, Sch Med, Dept Internal Med, Div Oncol, St Louis, MO 63110 USA
[5] Washington Univ, Div Biol & Biomed Sci, Sch Med, St Louis, MO 63110 USA
[6] Washington Univ, Sch Med, Dept Neurosci, St Louis, MO 63110 USA
[7] Washington Univ, Sch Med, Dept Pathol & Immunol, St Louis, MO 63110 USA
[8] Washington Univ, Dept Biol, Campus Box 1137, St Louis, MO 63130 USA
[9] Washington Univ, Dept Neurol, Sch Med, St Louis, MO 63110 USA