1. Dipartimento Farmaco-chimico, University of Bari, Via E. Orabona 4, I-70125 Bari, Italy; Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, S. Francisco 1, E-15782 Santiago de Compostela, Spain; and Institut de Chimie Thérapeutique, Université de Lausanne, BEP, CH-1015 Lausanne, Switzerland