1. Private Hemodialysis Unit, “Bionephros”, Athens, Greece;
2. Department of Pathology, Metropolitan Hospital, Athens, Greece;
3. Department of Nephrology, General Hospital of Chania, Chania, Greece;
4. Department of Nephrology, Evangelismos General Hospital, Athens, Greece;
5. Department of Pathology, University Hospital of Alexandroupoli, Alexandroupolis, Greece;
6. Department of Nephrology, University Hospital of Alexandroupoli, Alexandroupolis, Greece