[1] MED COLL VIRGINIA, DEPT PEDIAT, MCV STN, RICHMOND, VA 23298 USA
[2] NIAMDD, PROGRAM ARTIFICIAL KIDNEY CHRON UREMIA, BETHESDA, MD 20014 USA
[3] NHLBI, HYPERTENS ENDOCRINE BRANCH, STEROID & MINERAL METAB, BETHESDA, MD 20014 USA
[4] CHILDRENS HOSP, NATL MED CTR, DEPT PEDIAT, WASHINGTON, DC 20009 USA
[5] GEORGE WASHINGTON UNIV, SCH MED, WASHINGTON, DC 20006 USA
[6] UNIV WISCONSIN, COLL AGR & LIFE SCI, DEPT BIOCHEM, MADISON, WI 53706 USA