Renal failure in children with hepatic failure undergoing liver transplantation

Over a 3½ year period, 133 children with hepatic failure underwent orthotopic liver transplantation (OLT) at our center. Renal failure (creatinine clearance <20 ml/min/1.73 m(2)) was present in 19 (14.3%) of these children. In seven of the 19 children, renal failure was present before OLT, and in the other 12 after OLT. The causes of renal failure included hepatorenal syndrome in seven, postischemic acute tubular necrosis in five, severe prerenal azotemia in five, and cyclosporine nephrotoxicity in two. Eight other patients died of renal failure while awaiting emergency transplantation. Of the total of 31 deaths among 133 children who underwent OLT, nine occurred in the 19 patients with renal failure. Thus patients with OLT and renal failure had a significantly higher mortality than other patients with transplants (P <0.025). Dialysis was not associated with improved survival. The majority of deaths in patients with renal failure were related to severe hemorrhage, thromboembolic events, and systemic fungal infections. Our experience suggests that renal failure is common in children with hepatic failure and is associated with reduced patient survival after OLT

A Mutant Ahr Allele Protects the Embryonic Kidney from Hydrocarbon-Induced Deficits in Fetal Programming

Background: The use of experimental model systems has expedited the elucidation of pathogenetic mechanisms of renal developmental disease in humans and the identification of genes that orchestrate developmental programming during nephrogenesis

Effect of renal Doppler ultrasound on the detection of nutcracker syndrome in children with hematuria

To assess the detection rate of nutcracker syndrome in children with isolated hematuria, renal Doppler ultrasound examinations were routinely performed on 216 consecutive children (176 microscopic hematuria and 40 gross hematuria). Renal Doppler ultrasound was also performed on 32 healthy normal children. The peak velocity (PV) was measured at the hilar portion of the left renal vein (LRV) and at the LRV between the aorta and the superior mesenteric artery. The PV at the aortomesenteric portion (P=0.003) and the PV ratios of the LRV (P=0.003) were significantly higher in children with hematuria than in normal children, while the PV at the hilar portion was not different. If a PV ratio of the LRV of at least 4.1 (the cut-off level set at the mean ±2 SD of the value for the normal children) was defined as abnormal, 72 cases (33.3%) in children with hematuria and no cases in normal children were diagnosed as having nutcracker syndrome. The prevalence of nutcracker syndrome is relatively high in children with isolated hematuria, and the inclusion of renal Doppler ultrasound as a screening examination has a substantial effect on the detection of nutcracker syndrome

Idiopathic membranous nephropathy in pediatric patients: presentation, response to therapy, and long-term outcome

<p>Abstract</p> <p>Background</p> <p>Idiopathic membranous nephropathy (IMN) is one of the most common causes of primary nephrotic syndrome in adults. However, it is a relatively rare entity in the pediatric population and there is a paucity of data about the incidence, prognosis, and optimal treatment of IMN in children and adolescents. We conducted this study to evaluate pediatric patients with IMN in order to clarify the presentation, response to therapy, and clinical outcome.</p> <p>Methods</p> <p>A retrospective chart review was performed on patients identified with biopsy-proven IMN between 1988–2005. Patients with systemic lupus erythematosus or hepatitis-related lesions were excluded. The following data were tabulated: age, gender, ethnicity, presenting clinical and laboratory findings, proteinuria in a first morning urine specimen, estimated glomerular filtration rate (GFR_e), histopathology, type and duration of treatment, and clinical status at final evaluation.</p> <p>Results</p> <p>13 cases of IMN were identified out of 460 renal biopsies performed for evaluation of primary kidney disease during the study interval. Mean age was 9.6 ± 4.6, gender 6 M:7 F, ethnicity 8 W:2 B:3 H. At the initial visit hematuria was present in 9 patients, edema in 5, nephrotic-range proteinuria in 5, and hypertension in 3. Mean urinary protein:creatinine ratio 3.3 ± 2.5 and all patients had a normal GFR_e. Classic glomerular findings of IMN were seen in all renal specimens, with concomitant interstitial changes in 2 cases. Treatment included an angiotensin converting enzyme inhibitor or angiotensin receptor blocker in 11 cases. Most patients were also given immunosuppressive medications – prednisone in 10, a calcineurin inhibitor in 5, and mycophenolate mofetil or azathioprine in 3 patients. At the last follow-up, 42 ± 35 months after the diagnostic biopsy, 7 children were hypertensive and the urine protein:creatinine ratio was 2.3 ± 3.1. The mean GFR_ewas 127 ± 57 mL/min/m². Three patients had Chronic Kidney Disease Stage 3, all of whom were also hypertensive.</p> <p>Conclusion</p> <p>IMN is a rare but serious glomerulopathy in pediatrics. We estimate that it accounts for approximately 3% of renal biopsies. Long-term prognosis is guarded because approximately 50% of patients may have evidence of progressive kidney disease.</p

A Novel, Low-Volume Method for Organ Culture of Embryonic Kidneys That Allows Development of Cortico-Medullary Anatomical Organization

Here, we present a novel method for culturing kidneys in low volumes of medium that offers more organotypic development compared to conventional methods. Organ culture is a powerful technique for studying renal development. It recapitulates many aspects of early development very well, but the established techniques have some disadvantages: in particular, they require relatively large volumes (1–3 mls) of culture medium, which can make high-throughput screens expensive, they require porous (filter) substrates which are difficult to modify chemically, and the organs produced do not achieve good cortico-medullary zonation. Here, we present a technique of growing kidney rudiments in very low volumes of medium–around 85 microliters–using silicone chambers. In this system, kidneys grow directly on glass, grow larger than in conventional culture and develop a clear anatomical cortico-medullary zonation with extended loops of Henle

Improving virtual screening of G protein-coupled receptors via ligand-directed modeling

G protein-coupled receptors (GPCRs) play crucial roles in cell physiology and pathophysiology. There is increasing interest in using structural information for virtual screening (VS) of libraries and for structure-based drug design to identify novel agonist or antagonist leads. However, the sparse availability of experimentally determined GPCR/ligand complex structures with diverse ligands impedes the application of structure-based drug design (SBDD) programs directed to identifying new molecules with a select pharmacology. In this study, we apply ligand-directed modeling (LDM) to available GPCR X-ray structures to improve VS performance and selectivity towards molecules of specific pharmacological profile. The described method refines a GPCR binding pocket conformation using a single known ligand for that GPCR. The LDM method is a computationally efficient, iterative workflow consisting of protein sampling and ligand docking. We developed an extensive benchmark comparing LDM-refined binding pockets to GPCR X-ray crystal structures across seven different GPCRs bound to a range of ligands of different chemotypes and pharmacological profiles. LDM-refined models showed improvement in VS performance over origin X-ray crystal structures in 21 out of 24 cases. In all cases, the LDM-refined models had superior performance in enriching for the chemotype of the refinement ligand. This likely contributes to the LDM success in all cases of inhibitor-bound to agonist-bound binding pocket refinement, a key task for GPCR SBDD programs. Indeed, agonist ligands are required for a plethora of GPCRs for therapeutic intervention, however GPCR X-ray structures are mostly restricted to their inactive inhibitor-bound state

Determination of the parton distribution functions of the proton using diverse ATLAS data from pp collisions at √s = 7, 8 and 13 TeV

This paper presents an analysis at next-to-next-to-leading order in the theory of quantum chromodynamics for the determination of a new set of proton parton distribution functions using diverse measurements in pp collisions at \sqrt{s} = 7, 8 and 13 TeV, performed by the ATLAS experiment at the Large Hadron Collider, together with deep inelastic scattering data from ep collisions at the HERA collider. The ATLAS data sets considered are differential cross-section measurements of inclusive W^{±} and Z/gamma^{*} boson production, W^{±} and Z boson production in association with jets, t\bar{t} production, inclusive jet production and direct photon production. In the analysis, particular attention is paid to the correlation of systematic uncertainties within and between the various ATLAS data sets and to the impact of model, theoretical and parameterisation uncertainties. The resulting set of parton distribution functions is called ATLASpdf21

Modelling and computational improvements to the simulation of single vector-boson plus jet processes for the ATLAS experiment

This paper presents updated Monte Carlo configurations used to model the production of single electroweak vector bosons (W, Z/gamma*) in association with jets in proton-proton collisions for the ATLAS experiment at the Large Hadron Collider. Improvements pertaining to the electroweak input scheme, parton-shower splitting kernels and scale-setting scheme are shown for multi-jet merged configurations accurate to next-to-leading order in the strong and electroweak couplings. The computational resources required for these set-ups are assessed, and approximations are introduced resulting in a factor three reduction of the per-event CPU time without affecting the physics modelling performance. Continuous statistical enhancement techniques are introduced by ATLAS in order to populate low cross-section regions of phase space and are shown to match or exceed the generated effective luminosity. This, together with the lower per-event CPU time, results in a 50% reduction in the required computing resources compared to a legacy set-up previously used by the ATLAS collaboration. The set-ups described in this paper will be used for future ATLAS analyses and lay the foundation for the next generation of Monte Carlo predictions for single vector-boson plus jets production

Measurement of the energy asymmetry in t(t)over-barj production at 13 TeV with the ATLAS experiment and interpretation in the SMEFT framework

A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using $$139\,{\mathrm {fb}}^{-1}$$ 139 fb - 1 of data collected by the ATLAS detector at the Large Hadron Collider during pp collisions at $$\sqrt{s}=13\,\text {TeV}$$ s = 13 TeV . The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering angle with respect to the beam axis. The energy asymmetry is measured in the semileptonic $$t{\bar{t}}$$ t t ¯ decay channel, and the hadronically decaying top quark must have transverse momentum above $$350\,\text {GeV}$$ 350 GeV . The results are corrected for detector effects to particle level in three bins of the scattering angle of the associated jet. The measurement agrees with the SM prediction at next-to-leading-order accuracy in quantum chromodynamics in all three bins. In the bin with the largest expected asymmetry, where the jet is emitted perpendicular to the beam, the energy asymmetry is measured to be $$-0.043\pm 0.020$$ - 0.043 ± 0.020 , in agreement with the SM prediction of $$-0.037\pm 0.003$$ - 0.037 ± 0.003 . Interpreting this result in the framework of the Standard Model effective field theory (SMEFT), it is shown that the energy asymmetry is sensitive to the top-quark chirality in four-quark operators and is therefore a valuable new observable in global SMEFT fits