http://jasn.asnjournals.org Journal of the American Society of Nephrology RSS feed -- recent Disease of the Month articles 1533-3450 Journal of the American Society of Nephrology 1046-6673 http://jasn.asnjournals.org/icons/banner/title.gif http://jasn.asnjournals.org http://jasn.asnjournals.org/cgi/content/short/18/6/1845?rss=1 Many of the known benefits of exercise in the general population are of particular relevance to the ESRD population. In addition, the poor physical functioning that is experienced by patients who are on dialysis is potentially addressable through exercise interventions. The study of exercise in the ESRD population dates back almost 30 yr, and numerous interventions, including aerobic training, resistance exercise training, and combined training programs, have reported beneficial effects. Recently, interventions during hemodialysis sessions have become more popular and have been shown to be safe. The risks of exercise in this population have not been rigorously studied, but there have been no reports of serious injury as a result of participation in an exercise training program. It is time that we incorporate exercise into the routine care of patients who are on dialysis, but identification of an optimal training regimen or regimens, according to patient characteristics or needs, is still needed to facilitate implementation of exercise programs.

]]> 2007-05-25 info:doi/10.1681/ASN.2007010009 American Society of Nephrology 6 18 1854 2007-06-01 1845 Disease of the Month http://jasn.asnjournals.org/cgi/content/short/18/6/1855?rss=1 Nephronophthisis (NPHP), an autosomal recessive cystic kidney disease, represents the most frequent genetic cause of end-stage kidney disease in the first three decades of life. Contrary to polycystic kidney disease, NPHP shows normal or diminished kidney size, cysts are concentrated at the corticomedullary junction, and tubulointerstitial fibrosis is dominant. NPHP can be associated with retinitis pigmentosa (Senior-Løken syndrome), liver fibrosis, and cerebellar vermis aplasia (Joubert syndrome) in approximately 10% of patients. Positional cloning of six novel genes (NPHP1 through 6) as mutated in NPHP and functional characterization of their encoded proteins have contributed to the concept of "ciliopathies." It has helped advance a new unifying theory of cystic kidney diseases. This theory states that the products of all genes that are mutated in cystic kidney diseases in humans, mice, or zebrafish are expressed in primary cilia or centrosomes of renal epithelial cells. Primary cilia are sensory organelles that connect mechanosensory, visual, osmotic, and other stimuli to mechanisms of cell-cycle control and epithelial cell polarity. The ciliary theory explains the multiple organ involvement in NPHP regarding retinitis pigmentosa, liver fibrosis, ataxia, situs inversus, and mental retardation. Mutations in NPHP genes cause defects in signaling mechanisms, including the noncanonical Wnt signaling pathway. The "ciliopathy" NPHP thereby is caused by defects in tissue differentiation and maintenance as a result of impaired processing of extracellular cues. Nephrocystins, the proteins that are encoded by NPHP genes, are highly conserved in evolution. Positional cloning of additional causative genes of NPHP will elucidate further signaling mechanisms that are involved, thereby establishing therapeutic approaches using animal models in mouse, zebrafish, and Caenorhabditis elegans.

]]> 2007-05-25 info:doi/10.1681/ASN.2006121344 American Society of Nephrology 6 18 1871 2007-06-01 1855 Disease of the Month