[1] Univ Calif Irvine, Med Ctr, Harold Simmons Ctr Kidney Dis Res & Epidemiol, Div Nephrol & Hypertens, Orange, CA USA
[2] Tibor Rubin Vet Affairs Med Ctr, Nephrol Sect, Long Beach, CA USA
[3] Univ Tennessee, Ctr Hlth Sci, Div Nephrol, Memphis, TN 38163 USA
[4] Memphis Vet Affairs Med Ctr, Nephrol Sect, Memphis, TN USA