1. Dialysis Vascular Access Research Group; Division of Nephrology; Department of Medicine; University of Cincinnati; Cincinnati Ohio
2. Division of Nephrology; Armed Forces Tao-Yuan General Hospital; Tao-Yuan County Taiwan
3. Department of Medicine of the National Defense Medical Center; Taipei Taiwan
4. Cincinnati VA Medical Center; Cincinnati Ohio
5. Department of Surgery; University of Cincinnati; Cincinnati Ohio
6. Department of Pathology; University of Cincinnati; Cincinnati Ohio