1 Research Unit for the Study of Hydromineral Metabolism, Department of Internal Medicine, Hôpital Erasme, Route de Lennik, 808, Brussels B-1070, Belgium. Electronic address: guy.decaux@skynet.be.
2 Research Unit for the Study of Hydromineral Metabolism, Department of Internal Medicine, Hôpital Erasme, Route de Lennik, 808, Brussels B-1070, Belgium.