[1] Johns Hopkins Univ, Dept Med, Baltimore, MD 21205 USA
[2] Johns Hopkins Univ, Dept Surg, Baltimore, MD 21205 USA
[3] Johns Hopkins Univ, Dept Radiol, Baltimore, MD 21205 USA
[4] Johns Hopkins Univ, Dept Pathol, Baltimore, MD 21205 USA
[5] Johns Hopkins Univ, Dept Biol Chem, Baltimore, MD 21205 USA
[6] Thomas Jefferson Univ, Dept Pathol Anat & Cell Biol, Philadelphia, PA 19107 USA