[1] Vet Adm Med Ctr, Metab Sect, San Francisco, CA 94121 USA
[2] Univ Calif San Francisco, San Francisco, CA 94143 USA
[3] Tufts Univ, Boston, MA 02111 USA
[4] Columbia Univ, Sch Med, New York, NY USA
[5] St Lukes Roosevelt Hosp, New York, NY 10025 USA
[6] Univ Alabama, Birmingham, AL USA
[7] Univ Vermont, Burlington, VT USA
[8] Merck Res Labs, Rahway, NJ USA