The investigators have recently demonstrated in a porcine model that PERC is associated acutely with significant deleterious effects on renal function. Following routine PERC, glomerular filtration rate (GFR) and renal plasma flow (RPF) decline by 50% in both the treated and the untreated kidney and return to normal when measured at 72 & 74 hours (n=3 pigs). Sodium excretion, however, was markedly below baseline at 72 and 74 hours in 2 of the 3 pigs. PAH extraction, a measure of the efficiency of renal tubular secretion of organic anions, averaged 43.5 ± 9.7% and 42.6 ± 14.1% at 72 and 74 hours for the 3 pigs. These values are substantially below the baseline value of 80.4 ± 4.0% measured in sham-PNL pigs.