The improvement in the anemia in patients with end-stage renal disease (ESRD) on continuous ambulatory peritoneal dialysis (CAPD) suggests that dialyzable substances present in the sera of uremic patients either inhibit erythropoiesis directly or inactivate erythropoietin (EPO). In the present study predialysis sera from patients with ESRD inhibited erythroid colony (CFU-E) (N = 10) formation to a significantly (P less than 0.01) greater degree than granulocyte-macrophage (CFU-GM) (N = 7) colony formation in mouse bone marrow (MBM) cultures. The polyamines spermine (SP) (18 to 560 nm/ml) and spermidine (SD) (4 to 648 nm/ml) exerted a more significant (P less than 0.05) inhibition of CFU-E (N greater than or equal to 5) than that of CFU-GM (N greater than or equal to 5) growth. Concentrations of 0.80, 1.0, and 1.5 nm/ml of putrescine (PU) were 92%, 85%, and 77% of erythroid colony (CFU-E) controls (N = 4) and 104%, 130%, and 127% of CFU-GM controls (N = 4). Putrescine (PU) at 1.5 nm/ml also produced a significant (P less than 0.05) inhibition of CFU-E, whereas CFU-GM were stimulated by PU. These data suggest that predialysis sera from uremic patients, as well as SP, SD, and PU, are selectively more inhibitory to CFU-E than CFU-GM growth. The immunoreactivity of EPO was not significantly changed when it was coincubated with SP, SD and PU and measured by radioimmunoassay. PU was found to inhibit noncompetitively the bioactivity of EPO in a CFU-E assay. These data support the hypothesis that polyamines may be important uremic toxins in the anemia of ESRD.

Chronic kidney disease (CKD) introduces a unique set of nutritional challenges for the growing and developing child. This article addresses initial evaluation and ongoing assessment of a child with CKD. It aims to provide an overview of nutritional challenges unique to a pediatric patient with CKD and practical management guidelines. Caloric assessment in children with CKD is critical as many factors contribute to poor caloric intake. Tube feeding is a practical option to provide the required calories and fluid in children who have difficulty with adequate oral intake. Protein intake should not be limited and should be further adjusted for protein loss with dialysis. Supplementation or restriction of sodium is patient specific. Urine output, fluid status, and modality of dialysis are factors that influence sodium balance. Hyperkalemia poses a significant cardiac risk, and potassium is closely monitored. In addition to a low potassium diet, potassium binders may be prescribed to reduce potassium load from oral intake. Phosphorus and calcium play a significant role in cardiovascular and bone health. Phosphorus binders have helped children and families manage phosphorus levels in conjunction with a phosphorusrestricted diet. Nutritional management of children with CKD is a challenge that requires continuous reassessment and readjustment as the child ages, CKD progresses, and urine output decreases.

The ability to minimize and even resolve warts can improve quality of life by reducing risk of skin malignancies and emotional distress in solid organ transplant patients. Leflunomide is a potential therapeutic option for posttransplantation patients with skin warts because it serves both as an adjunct to the immunosuppressive regimen and an antiviral agent.

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