[1] Wake Forest Univ, Sch Med, Dept Pediat, Winston Salem, NC 27157 USA
[2] RTI Int, Res Triangle Pk, NC USA
[3] Yale Univ, Sch Med, Dept Pediat, New Haven, CT 06510 USA
[4] Univ Rochester, Sch Med & Dent, Dept Pediat, Rochester, NY 14642 USA
[5] Univ Miami, Sch Med, Dept Pediat, Miami, FL USA
[6] Emory Univ, Sch Med, Dept Pediat, Atlanta, GA USA
[7] Women & Infants Hosp Rhode Isl, Dept Pediat, Providence, RI USA
[8] Indiana Univ, Sch Med, Dept Pediat, Indianapolis, IN 46202 USA
[9] NICHHD, Rockville, MD USA