[1] Univ Aberdeen, Inst Med Sci, Dept Med & Therapeut, Aberdeen AB25 2ZD, Scotland
[2] Emma Childrens Hosp, Amsterdam Med Ctr, Dept Clin Chem, Amsterdam, Netherlands
[3] Univ Alabama, Dept Pharmacol & Toxicol, Birmingham, AL USA
[4] US FDA, Off Clin Pharmacol & Biopharmaceut, Rockville, MD 20857 USA
[5] NCI, Lab Metab, NIH, Bethesda, MD USA
[6] Univ Extremadura, Fac Ciencias, Lab Bioquim & Biol Mol, E-06071 Badajoz, Spain