From the National Institutes of Health, Bethesda, MD.

The author has disclosed that she has no significant relationships with, or financial interest in, any commercial companies pertaining to this article.

Reprints: Lyric A. Jorgenson, PhD, National Institutes of Health, Bldg 1, 1 Center Dr, Room 103, Bethesda, MD 20814. E-mail: jorgensonla@od.nih.gov.