1. Department of Pediatrics (J.Z., E.L.S., V.K.), Vanderbilt University Medical Center, Nashville, TN.
2. Department of Pathology, Microbiology and Immunology (J.Z.), Vanderbilt University Medical Center, Nashville, TN.
3. Department of Molecular Physiology and Biophysics (A.K.), Vanderbilt University Medical Center, Nashville, TN.
4. Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN (A.K.).