Atypical hemolytic uremic syndrome (aHUS) is a disease characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury. The histopathologic lesions of aHUS include thrombotic microangiopathy involving the glomerular capillaries and thrombosis involving arterioles or interlobar arteries. Extra-renal manifestations occur in up to 20% of patients. The majority of aHUS is caused by complement system defects impairing ordinary regulatory mechanisms. Activating events therefore lead to unbridled, ongoing complement activity producing widespread endothelial injury. Pathologic mutations include those resulting in loss-of-function in a complement regulatory gene (CFH, CFI, CD46 or THBD) or gain-of-function in an effector gene (CFB or C3). Treatment with the late complement inhibitor, eculizumab – a monoclonal antibody directed against C5 – is effective.

The incidence of early stage renal cell carcinoma (RCC) is increasing and observational studies have shown equivalent oncological outcomes of partial versus radical nephrectomy for stage I tumours. Population studies suggest that compared with radical nephrectomy, partial nephrectomy is associated with decreased mortality and a lower rate of postoperative decline in kidney function. However, rates of chronic kidney disease (CKD) in patients who have undergone nephrectomy might be higher than in the general population. The risks of new-onset or accelerated CKD and worsened survival after nephrectomy might be linked, as kidney insufficiency is a risk factor for cardiovascular disease and mortality. Nephron-sparing approaches have, therefore, been proposed as the standard of care for patients with type 1a tumours and as a viable option for those with type 1b tumours. However, prospective data on the incidence of de novo and accelerated CKD after cancer nephrectomy is lacking, and the only randomized trial to date was closed prematurely. Intrinsic abnormalities in non-neoplastic kidney parenchyma and comorbid conditions (including diabetes mellitus and hypertension) might increase the risks of CKD and RCC. More research is needed to better understand the risk of CKD post-nephrectomy, to develop and validate predictive scores for risk-stratification, and to optimize patient management.

A B S T R A C TBackground: Sodium disarrays are common in peritoneal dialysis (PD) patients, and may be associated with adverse outcomes in this population. However, few studies of limited sample size have examined the association of serum sodium with mortality in PD patients, with inconsistent results. We hypothesized that both hypo-and hypernatremia are associated with higher death risk in a nationally representative cohort of US PD patients. Methods: We sought to examine the association of serum sodium over time and mortality among 4687 adult incident PD patients from a large US dialysis organization who underwent one or more serum sodium measurements within the first 3 months of dialysis over January 2007 to December 2011. We examined the association of time-dependent and baseline sodium with allcause mortality as a proxy of short-and long-term sodium-mortality associations, respectively. Hazard ratios were estimated using Cox models with three adjustment levels: minimally adjusted, case-mix adjusted, and case-mix þ laboratory adjusted. Results: In time-dependent analyses, sodium levels <140 mEq/ L were associated with incrementally higher death risk in casemix models (ref: 140 to <142 mEq/L); following laboratory covariate adjustment, associations between lower sodium and higher mortality remained significant for levels <136 mEq/L. In analyses using baseline values, sodium levels <140 mEq/L were associated with higher mortality risk across all models (ref: 140 to <142 mEq/L). Conclusions: In PD patients, lower time-dependent and baseline sodium levels were independently associated with higher death risk. Further studies are needed to determine whether correction of dysnatremia improves longevity in this population.

Mitochondrial Oxa1p homologs have been shown to function in protein export and membrane insertion in bacteria, mitochondria and chloroplasts, but their mode of action, organismal distribution and evolutionary origins are poorly understood. All sequenced homologs of Oxa1p were retrieved from the databases and multiply aligned. All organisms with a fully sequenced genome possess at least one Oxa1p homolog showing that the family is truly ubiquitous. Most prokaryotes possess just one Oxa1p homolog, but several Gram-positive bacteria and one archaeon possess two, and eukaryotes may have as many as six. Although these proteins vary in length over a 5-fold range, they exhibit a common hydrophobic core region of about 200 residues. Multiple sequence alignments reveal conserved residues and provide the basis for structural and phylogenetic analyses that serve to characterize the Oxa1 family.

Physician caseload may be a predictor of patient outcomes associated with various medical conditions and procedures, but the association between patient-physician ratio and mortality among patients undergoing hemodialysis has not been determined. We examined whether a higher patient-nephrologist ratio affects patient mortality risk using de-identified data from DaVita dialysis clinics and the U.S. Renal Data System. A total of 41 nephrologists with a caseload of 50-200 hemodialysis patients from an urban California region were retrospectively ranked according to their hemodialysis patient mortality rate during a 6-year period between 2001 and 2007. We calculated all-cause mortality hazard ratios for each nephrologist and compared patient-and provider-level characteristics between the 10 nephrologists with the highest patient mortality rates and the 10 nephrologists with the lowest patient mortality rates. Nephrologists with the lowest patient mortality rates had significantly lower patient caseloads than nephrologists with the highest mortality rates (median [interquartile range], 65 [55-76] versus 103 [78-144] patients per nephrologist, respectively; P,0.001). Additionally, patients treated by nephrologists with the lowest patient mortality rates received higher dialysis doses, had longer sessions, and received more kidney transplants. In demographic characteristic-adjusted analyses, each 50-patient increase in caseload was associated with a 2% increase in patient mortality risk (hazard ratio, 1.02; 95% confidence interval, 1.00 to 1.04; P,0.001). Hence, these results suggest that nephrologist caseload influences hemodialysis patient outcomes, and future research should focus on identifying the factors underlying this association.