[1] JOHNS HOPKINS UNIV, SCH MED, BALTIMORE, MD 21218 USA
[2] KANTONSSPITAL, CH-4004 BASEL, SWITZERLAND
[3] WASHINGTON UNIV, SCH MED, ST LOUIS, MO 63130 USA
[4] VET ADM HOSP, W ROXBURY, MA 02132 USA
[5] ST ELIZABETHS HOSP, BOSTON, MA USA
[6] UNIV ROCHESTER, ROCHESTER, NY 14627 USA
[7] UNIV N CAROLINA, CHAPEL HILL, NC 27514 USA
[8] BETH ISRAEL HOSP, BOSTON, MA 02215 USA
[9] CATHOLIC UNIV LEUVEN, B-3000 LOUVAIN, BELGIUM