1. From the Center for Biomedical Research, Department of Internal Medicine, Clinica Universitaria, University of Navarra, Pamplona, Spain (A.C., J.P.), and the Department of Pathology and Laboratory Medicine, Division of Biology and Medicine, Brown University, Providence, R.I. (A.C., N.F.). Address reprint requests to Dr. Fausto at the Department of Pathology, Box G-B518, Brown University, Providence, RI 02912. Supported by Beca Sandoz 1988 from the Spanish Society of Internal Medicine and Beca PF90...