1. Division of Nephrology, University and Civic HospitaI, Brescia, Italy
2. Baxter Healthcare Corporation, Round Lake, Illinois, USA
3. Nephrology and Dialysis Service, S. Lazzaro Hospital, Alba, Italy
4. Division of Nephrology and Dialysis, Policlinico, Milano, Italy
5. Division of Nephrology and Dialysis, Provincial Hospital, Busto Arsizio, Italy
6. Division of Nephrology, San Bortolo Hospital, Vicenza, Italy
7. Nephrology and Dialysis Service, Civil Hospital, Piacenza, Italy