Figure 1. Plasma urea concentrations in apolipoprotein E–deficient (apo-E −/−) mice with chronic renal failure (CRF). Figure 1. Plasma urea concentrations in apolipoprotein E–deficient (apo-E −/−) mice with chronic renal failure (CRF). Plasma urea concentrations after 5/6 nephrectomy (CRF mice), unilateral nephrectomy (UNX mice), or no surgery at day 0. ▪ CRF mice (n = 28); •, UNX mice (n = 24); ○, no-surgery mice (n = 23). Values are mean ± SEM. *P < 0.01 and ** P < 0.001 compared with the no-surgery group. Susanne Bro et al. JASN 2003;14:2466-2474 ©2003 by American Society of Nephrology