[1] Harvard Univ, Dept Pathol, Sch Med, Ctr Vasc Biol Res,Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA
[2] Univ Calif San Francisco, Dept Surg & Anat, Ctr Bioengn & Tissue Regenerat, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Pathol, San Francisco, CA USA
[4] Univ Calif San Francisco, Dept Neurol Surg & Anat, San Francisco, CA 94143 USA