Impact of pH on Urine Chemistry Assayed on Roche Analyzers.

BACKGROUND: The pH may impact the concentration of certain urinary parameters, making urine pre-treatment questionable. METHODS: 1) Determining the impact of pH in vitro on the urinary concentration of chemistry parameters assayed on Roche Modular analyzers. 2) Evaluating whether concentrations depended on pH in non-pretreated urines from patients. RESULTS: 1) The optimal urinary pH values for each measurement were: 6.3 ± 0.8 (amylase), < 5.5 (calcium and magnesium), < 6.5 (phosphorus), > 6.5 (uric acid). Urinary creatinine, sodium and urea concentrations were not pH-dependent. 2) In urines from patients, the pH was negatively associated with the concentration of some urinary parameters. However, concentrations of all the parameters were strongly and positively correlated with urinary creatinine, and relationships with pH were no longer evidenced after creatinine-normalization. CONCLUSIONS: The need for urine pH adjustment does not seem necessary when considering renal function. However, from an analytical and accreditation standpoint, the relationship between urine pH and several parameters justifies its measurement.

Spectrum of mutations in cystinuria patients presenting with prenatal hyperechoic colon.

Cystinuria is a heterogeneous, rare but important cause of inherited kidney stone disease due to mutations in 2 genes: SLC3A1 and SLC7A9. Antenatal hyperechoic colon (HEC) has been reported in some patients as a non-pathological consequence of the intestinal transport defect. We report 83 patients affected by cystinuria: 44 presented prenatally with a HEC (HEC group) and 39 with a classical postnatal form (CC group). SLC3A1 and SLC7A9 were sequenced. All patients were fully genotyped, and the relationship between the genotype and clinical features was analyzed. We identified mutations in SLC3A1 in 80% of the HEC group and in only 49% of the CC group. The SLC3A1 p.Thr216Met mutation was found in 21% of the alleles in the HEC group but was never found in the CC group. Most of the mutations found in the HEC group were considered severe mutations in contrast with the CC group. Twenty-five novel mutations were reported. This study shows a relationship between genotype and the clinical form of cystinuria, suggesting that only the patients with the most severe mutations presented with an HEC. These results emphasized the need for prenatal cystinuria screening using classical third-trimester ultrasound scan and the early management of suspected newborns.

[Simultaneous bilateral percutaneous nephrolithotomy: Series of 60 cases]. / Néphrolithotomie percutanée bilatérale en un temps: série de 60 cas.

OBJECTIVE: Retrospective evaluation of the efficacy and morbidity of simultaneous bilateral percutaneous nephrolithotomy (SB-PCNL). METHODS: From January 1993 to July 2009, 60 patients have undergone SB-PCNL over a series of 1709 PCNL. Thirty men and 30 women, mean age 45 years old (13-78), were treated for bilateral renal stones (120 kidneys) of 1177 mm(2) (268-4972 mm(2)); 25 were complete staghorn stones. RESULTS: Operating time for the first side of PCNL was 80 min (30-270) and 45 min (10-90) for the opposite side. Overall OR occupation was 188 min (90-360). Forty-five patients were stone free after one session; 15 patients (25%) have a complementary treatment to be stone free: five PCNL (one bilateral); eight ESWL (four with JJ stent) and two flexible ureteroscopy. No blood transfusion was required. Renal function was unchanged at 1 month. Clavien grade for complications were as follows: two grade IIIb, one grade IVa and one grade IVb. Hospitalization stay was 4±4.9 days (2-35) taking account of two major sepsis (one pulmonary and one septicemia). CONCLUSION: SB-PCNL was well tolerated with comparable morbidity and efficacy to PCNL performed on each side in two separate sessions. Nevertheless, SB-PCNL has to be performed for selected patients in expert centers.

Advanced glycation end products regulate extracellular matrix protein and protease expression by human glomerular mesangial cells.

Advanced glycation end products (AGEs) may play a role in the pathogenesis of diabetic nephropathy, by modulating extracellular matrix turnover. AGEs are known to activate specific membrane receptors, including the receptor for AGE (RAGE). In the present study, we analyzed the various receptors for AGEs expressed by human mesangial cells and we studied the effects of glycated albumin and of carboxymethyl lysine on matrix protein and remodelling enzyme synthesis. Membrane RAGE expression was confirmed by FACS analysis. Microarray methods, RT-PCR, and Northern blot analysis were used to detect and confirm specific gene induction. Zymographic analysis and ELISA were used to measure the induction of tPA and PAI-1. We show herein that cultured human mesangial cells express AGE receptor type 1, type 2 and type 3 and RAGE. AGEs (200 microg/ml) induced at least a 2-fold increase in mRNA for 10 genes involved in ECM remodelling, including tPA, PAI-1 and TIMP-3. The increase in tPA synthesis was confirmed by fibrin zymography. The stimulation of PAI-1 synthesis was confirmed by ELISA. AGEs increased PAI-1 mRNA through a signalling pathway involving reactive oxygen species, the MAP kinases ERK-1/ERK-2 and the nuclear transcription factor NF-kappaB, but not AP-1. Carboxymethyl lysine (CML, 5 microM), which is a RAGE ligand, also stimulated PAI-1 synthesis by mesangial cells. In addition, a blocking anti-RAGE antibody partially inhibited the AGE-stimulated gene expression and decreased the PAI-1 accumulation induced by AGEs and by CML. Inhibition of AGE receptors or neutralization of the protease inhibitors TIMP-3 and PAI-1 could represent an important new therapeutic strategy for diabetic nephropathy.

MR imaging features of acute bilateral renal cortical necrosis.

Bilateral renal cortical necrosis (BRCN) is an uncommon cause of acute renal failure. Kidney biopsy, arteriography, and contrast-enhanced computed tomography (CT) are usually used to diagnose BRCN. However, these methods can have potentially serious side effects. We report two cases in which magnetic resonance imaging (MRI) evidenced characteristic features of BRCN, which were confirmed by histological findings and arteriography and correlated with clinical evolution. In the first case report, the diagnosis of a massive and complete cortical necrosis variety was suggested on MRI that showed a thin rim of low signal intensity along border of kidneys. It was confirmed on kidney biopsy, and the renal function did not recover. The second case is an incomplete form with cortical patchy areas of low signal intensity. In these two patients, MRI helped to establish an early diagnosis of BRCN with characteristic representative findings, without the potential nephrotoxic effects of iodinated contrast that has to be used in CT and arteriography. Kidney biopsy, besides the risks of complications, provides only a parceled analysis of the renal tissue and therefore does not allow any conclusion as to the extension of cortical necrosis. MRI may be of great help for the diagnosis and follow-up of acute renal cortical necrosis.

Feasibility and safety of ultrasound-aided thoracentesis in mechanically ventilated patients.

OBJECTIVE: Thoracentesis in a ventilated patient is rarely performed because of the risk of pneumothorax. We have evaluated the safety of this procedure when aided by ultrasound. DESIGN: Prospective study. SETTING: Medical intensive care unit, university-affiliated hospital. PATIENTS: 45 procedures were performed in 40 consecutive patients with ultrasound signs of pleural effusion, all mechanically ventilated. INTERVENTIONS: Pleural effusion was defined on ultrasound as a collection of fluid between parietal and visceral pleura leading to variations in interpleural distance during breathing. When the interpleural distance was >/= 15 mm and visible over three intercostal spaces, a needle (16 or 21 G) was inserted after ultrasound localization in a patient in either dorsal or lateral decubitus. RESULTS: No complication occurred in the 45 thoracenteses. Fluid was obtained in 44 of 45 procedures, thus confirming the diagnosis of pleural effusion. The procedure was immediate (less than 10 s) in 40 of 45 cases. It was easy (i. e., keeping the patient supine) in 22 of 45 procedures. In 44 cases where fluid was obtained, only 27 bedside radiographs revealed signs of effusion, whereas 17 showed absence of a visible effusion. Ultrasound thus appeared more efficient than bedside X-ray in detecting pleural effusion. CONCLUSIONS: If basic rules are followed, ultrasound localization makes thoracentesis a safe, easy and simple procedure in patients on mechanical ventilation.