From the *Department of Paediatrics, Children's Hospital at London Health Science Centre, University of Western Ontario, London, Ontario, Canada; and †Department of Anesthesiology, University of Colorado Health Science Center, Denver, Colorado, USA.
Received for publication September 11, 2007; accepted November 5, 2007.
Financial support: The United States National Institutes of Health/NIDDK supported this work (grant P30 DK048520-10; Clinical Nutrition Research Unit, Mass Spectrometry Core).
The study was also supported by grants from the Research Institute of the Children's Hospital of Eastern Ontario and Fujisawa Canada, Inc.
Correspondence: Guido Filler, MD, PhD, FRCPC, Professor and Chair, Department of Paediatrics, Children's Hospital of Western Ontario, 800 Commissioners Road East, London, Ontario, Canada N6A 5W9 (e-mail: [email protected]).