Background: Kidney biopsy is a vital tool in the diagnosis of kidney disease. Although it has become a routine procedure, it is not complication-free. Some serious complications of percutaneous kidney biopsy include retroperitoneal hemorrhage and death. There is an increased belief that smaller biopsy needle size results in a lower complication rate. As renal pathologists, we witness an increased number of kidney biopsies performed with a small needle size (as low as gauge 22), which results in inadequate tissue sampling and often non-diagnostic biopsy results. Herein we report the diagnostic value of kidney biopsies according to the size of the biopsy needles. Methods: We performed kidney biopsies from nephrectomy specimens using biopsy needles of different sizes. Morphologic parameters were analyzed. Results: We found that biopsies performed by small needles (gauges 20 and 22) contain significantly lower numbers of glomeruli and blood vessels, which limits pathologic evaluation. Data from our institution do not show differences in kidney biopsy complication rates between 16- and 18-gauge needles. Conclusions: Our data indicate that small biopsy needles do not provide sufficient material for diagnosis, and they increase the likelihood for a repeat biopsy.

Background Endothelial microparticles (EMP) are membrane vesicles shed from endothelial cell in response to injury, activation or apoptosis. Kidney transplantation (KTx) is the treatment of choice for patients with end stage kidney disease (ESKD). The aim of this study was to analyze changes in EMP and serum creatinine (SCr) in patients following KTx. Methods Blood was periodically collected from patients before (pre-KTx) and after KTx for two months. EMP were identified as CD31+/CD42b− microparticles and quantified by fluorescence-activated cell scanning. Results This study included 213 KTx, 14 kidney/pancreas (KPTx) recipients and 60 healthy donors prior to donation. The recipients were divided into 5 groups based on the cause of ESKD. No differences in the quantity of circulating EMP were seen in the pre-KPTx or KTx recipient sera and healthy donor sera. Patients with ESKD secondary to diabetes mellitus, obstructive/inherited kidney disease and autoimmune disease had a decrease in both circulating EMP and SCr by day 60 after KTx. Conclusion Reduction in both circulating EMP and SCr was seen after kidney KTx in patients with selective ESKD.

Drug induced Long QT syndrome results primarily from block of the cardiac potassium channel heRG (human-ether-a-gogo related gene). In some cases prolongation of the QT interval can result in the lethal arrhythmia torsade de pointes, an arrhythmia characterized by a rapid heart rate and severely compromised cardiac output. Many patients requiring medication present with abnormal serum electrolyte levels due to a variety of conditions including gastrointestinal dysfunction, renal and endocrine disorders, diuretic use, alcoholism and aging. Extracellular cations have significant influence on HERG channel gating and in some instances they have been shown to alter drug block of heRG. however, the mechanisms by which drug block is altered in different extracellular cation solutions are not well understood. In this study, heRG block by quinidine and cisapride was assessed in extracellular solutions of calcium, potassium, rubidium, cesium and tetraethylammonium (TeA) using two-electrode voltage clamping of Xenopus oocytes. Consistent with previous reports we show that increases in extracellular potassium reduce heRG block by quinidine and cisapride. We also show that increasing extracellular rubidium and cesium reduced heRG block by quinidine and cisapride whereas increasing extracellular calcium and extracellular TeA did not alter heRG block by quinidine and cisapride. These results demonstrate that at lower extracellular potassium concentrations, the permeant ion is almost exclusively responsible for the reduction in quinidine and cisapride block of heRG due to increases in extracellular potassium.