47 research outputs found

    Ca2+ Extrusion by NCX Is Compromised in Olfactory Sensory Neurons of OMP−/− Mice

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    The role of olfactory marker protein (OMP), a hallmark of mature olfactory sensory neurons (OSNs), has been poorly understood since its discovery. The electrophysiological and behavioral phenotypes of OMP knockout mice indicated that OMP influences olfactory signal transduction. However, the mechanism by which this occurs remained unknown.We used intact olfactory epithelium obtained from WT and OMP(-/-) mice to monitor the Ca(2+) dynamics induced by the activation of cyclic nucleotide-gated channels, voltage-operated Ca(2+) channels, or Ca(2+) stores in single dendritic knobs of OSNs. Our data suggested that OMP could act to modulate the Ca(2+)-homeostasis in these neurons by influencing the activity of the plasma membrane Na(+)/Ca(2+)-exchanger (NCX). Immunohistochemistry verifies colocalization of NCX1 and OMP in the cilia and knobs of OSNs. To test the role of NCX activity, we compared the kinetics of Ca(2+) elevation by stimulating the reverse mode of NCX in both WT and OMP(-/-) mice. The resulting Ca(2+) responses indicate that OMP facilitates NCX activity and allows rapid Ca(2+) extrusion from OSN knobs. To address the mechanism by which OMP influences NCX activity in OSNs we studied protein-peptide interactions in real-time using surface plasmon resonance technology. We demonstrate the direct interaction of the XIP regulatory-peptide of NCX with calmodulin (CaM).Since CaM also binds to the Bex protein, an interacting protein partner of OMP, these observations strongly suggest that OMP can influence CaM efficacy and thus alters NCX activity by a series of protein-protein interactions

    Canagliflozin and Renal Outcomes in Type 2 Diabetes and Nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to 300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m 2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    Bi-allelic Loss-of-Function CACNA1B Mutations in Progressive Epilepsy-Dyskinesia.

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    The occurrence of non-epileptic hyperkinetic movements in the context of developmental epileptic encephalopathies is an increasingly recognized phenomenon. Identification of causative mutations provides an important insight into common pathogenic mechanisms that cause both seizures and abnormal motor control. We report bi-allelic loss-of-function CACNA1B variants in six children from three unrelated families whose affected members present with a complex and progressive neurological syndrome. All affected individuals presented with epileptic encephalopathy, severe neurodevelopmental delay (often with regression), and a hyperkinetic movement disorder. Additional neurological features included postnatal microcephaly and hypotonia. Five children died in childhood or adolescence (mean age of death: 9 years), mainly as a result of secondary respiratory complications. CACNA1B encodes the pore-forming subunit of the pre-synaptic neuronal voltage-gated calcium channel Cav2.2/N-type, crucial for SNARE-mediated neurotransmission, particularly in the early postnatal period. Bi-allelic loss-of-function variants in CACNA1B are predicted to cause disruption of Ca2+ influx, leading to impaired synaptic neurotransmission. The resultant effect on neuronal function is likely to be important in the development of involuntary movements and epilepsy. Overall, our findings provide further evidence for the key role of Cav2.2 in normal human neurodevelopment.MAK is funded by an NIHR Research Professorship and receives funding from the Wellcome Trust, Great Ormond Street Children's Hospital Charity, and Rosetrees Trust. E.M. received funding from the Rosetrees Trust (CD-A53) and Great Ormond Street Hospital Children's Charity. K.G. received funding from Temple Street Foundation. A.M. is funded by Great Ormond Street Hospital, the National Institute for Health Research (NIHR), and Biomedical Research Centre. F.L.R. and D.G. are funded by Cambridge Biomedical Research Centre. K.C. and A.S.J. are funded by NIHR Bioresource for Rare Diseases. The DDD Study presents independent research commissioned by the Health Innovation Challenge Fund (grant number HICF-1009-003), a parallel funding partnership between the Wellcome Trust and the Department of Health, and the Wellcome Trust Sanger Institute (grant number WT098051). We acknowledge support from the UK Department of Health via the NIHR comprehensive Biomedical Research Centre award to Guy's and St. Thomas' National Health Service (NHS) Foundation Trust in partnership with King's College London. This research was also supported by the NIHR Great Ormond Street Hospital Biomedical Research Centre. J.H.C. is in receipt of an NIHR Senior Investigator Award. The research team acknowledges the support of the NIHR through the Comprehensive Clinical Research Network. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR, Department of Health, or Wellcome Trust. E.R.M. acknowledges support from NIHR Cambridge Biomedical Research Centre, an NIHR Senior Investigator Award, and the University of Cambridge has received salary support in respect of E.R.M. from the NHS in the East of England through the Clinical Academic Reserve. I.E.S. is supported by the National Health and Medical Research Council of Australia (Program Grant and Practitioner Fellowship)

    Assessment of Key Environmental Factors Influencing the Sedimentation and Aggregation Behavior of Zinc Oxide Nanoparticles in Aquatic Environment

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    Zinc oxide nanoparticles (ZnO NPs) are among the most widely used engineered nanoparticles (ENPs) in various commercial sectors to achieve both social and economic benefits. The post-use release of these NPs to the environment is inevitable, and may pose threat to the human and eco-system. In the present study, we investigated the influence of single and multiple environmental factors on sedimentation behavior of ZnO NPs. The fractional-factorial method based on Taguchi orthogonal array (OA) L27(313) design matrix was used for systematic investigation on the contribution and significance of multiple factors and their interactions. The result of single-factor showed that the ZnO NPs were unstable at or near pHzpc, with high electrolyte concentration; however, the adsorption of natural organic matter (NOM) i.e., humic acid, salicylic acid, and citric acid reverses the surface charge and enhanced NP stability. The Fourier transform infrared (FT-IR) analysis confirms the organic capping ligands on the NP surface. Moreover, the matrix result of analysis of variance (ANOVA) showed that electrolyte concentration and type, and NOM concentration were the most significant factors (p &lt; 0.001) in promoting and influencing aggregation, while the interaction between the factors was also found insignificant. In addition, the result of aggregation kinetics and environmental water samples indicated that the mobility of ENPs may vary substantially in an environment with complex and heterogeneous matrices. This study may contribute to better understanding and prediction of the sedimentation behavior and fate of ZnO NPs in aqueous environments, to facilitate their sustainable use in products and process

    Comparison of the rating scale and the standard gamble in measuring patient preferences for outcomes of gallstone disease.

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    To estimate patient preferences for gallstone-related treatments and outcomes, and assess how preferences vary by patient characteristics and scaling technique, the authors randomly assigned 40 patients without gallstones to interviews based on a rating scale (n = 22) and a standard gamble (n = 18). The patients assigned preference values (possible values 0 to 1) to open cholecystectomy (mean 0.45 by rating scale, 0.78 by standard gamble), laparoscopic cholecystectomy (0.71, 0.91), extracorporeal shock-wave lithotripsy (0.77, 0.89), acute cholecystitis (0.36, 0.77), lifetime biliary colic (0.41, 0.71), postcholecystectomy syndrome (0.43, 0.79), asymptomatic stone necessitating treatment with bile acids (0.76, 0.96), and surgical scar (0.79, 0.998). Preferences varied little by age, gender, or race. Standard gamble values were highly correlated with, but significantly greater than, rating scale values. The authors conclude that patients' preferences for gallstone-related conditions generally are significantly less than one, and differ markedly by the scaling technique used to derive them. These results should be considered when patient preferences are incorporated into analyses of gallstone treatments

    Taguchi Orthogonal Array Dataset for the Effect of Water Chemistry on Aggregation of ZnO Nanoparticles

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    The dynamic nature of engineered nanoparticle (ENP) aggregation behavior and kinetics are of paramount importance in the field of toxicological and environmental nanotechnology. The Taguchi orthogonal array (OA) L27(313) matrix based on a fractional factorials design was applied to systematically evaluate the contribution and significance of water chemistry parameters (pH, temperature, electrolyte, natural organic matter (NOM), content and type) and their interactions in the aggregation behavior of zinc oxide nanoparticles (ZnO NPs). The NPs were dispersed into the solution using a probe-sonicator cell crusher (Bio-safer, 1200-90, Nanjing, China). The data were obtained from UV&ndash;Vis spectroscopy (Optizen 2120 UV, Mecasys, Daejeon, Korea), Fourier Transform Infrared Spectrometery (FT-IR 4700, spectroscopy, a JASCO Analytical Instruments, Easton, Pennsylvania, USA) and particle electrophoresis (NanoZS, Zetasizer, Malvern Instruments Ltd., Worcestershire, UK). The dataset revealed that Taguchi OA matrix is an efficient approach to study the main and interactive effects of environmental parameters on the aggregation of ZnO NPs. In addition, the aggregation profile of ZnO NPs was significantly influenced by divalent cations and NOM. The result of the FT&ndash;IR data presents a possible mechanism of ZnO NP stabilization in the presence of different NOM. This data may be helpful to predict the aggregation behavior of ZnO NPs in environmental and ecotoxicological contexts

    Influence of Organic Ligands on the Colloidal Stability and Removal of ZnO Nanoparticles from Synthetic Waters by Coagulation

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    The large-scale production and usage of zinc oxide nanoparticles (ZnO NPs) may lead to their post-release into the aquatic environment. In this study, the effect of hydrophobic/hydrophilic organic ligands on sorption and sedimentation of ZnO NPs has been systematically investigated. In addition, the coagulation efficiency of ZnO NPs, Zn2+, dissolved organic carbon (DOC), and UV254 with varying ferric chloride (FC) dosages in synthetic waters were also evaluated. The results showed that the higher concentration of organic ligands, i.e., humic acid (HA), salicylic acid (SA), and L-cysteine (L-cys) reduced the &zeta;-potential and hydrodynamic diameter (HDD) of particles, which enhanced the NPs stability. The adsorption of organic ligands onto ZnO NPs was fitted with the Langmuir model, with maximum adsorption capacities of 143, 40.47, and 66.05 mg/g for HA, SA and L-cys respectively. Removal of up to 95% of ZnO NPs and Zn2+ was achieved in studied waters at the effective coagulation zone (ECR), above which excess charge induced by coagulant restabilized the NPs in suspension. Moreover, the removal rate of DOC and UV254 were found to be higher in hydrophobic waters than hydrophilic waters. The width of ECR strongly depends on the characteristics of source water. The waters with hydrophobic ligand and higher UV254 values require more coagulant than hydrophilic waters to achieve the similar ZnO NPs and Zn2+ removal. The results of Fourier transform infrared (FT-IR) analysis of ZnO NPs composite contaminant flocs indicated that the combined effect of enmeshment and charge neutralization might be a possible removal mechanism. These findings may facilitate the prediction of fate, transport, and removal of ZnO NPs in the natural waters, and might contribute to risk assessment, as well as decision making about engineered nanoparticles (ENPs) in aquatic systems

    Nivolumab Plus Ipilimumab Versus EXTREME Regimen as First-Line Treatment for Recurrent/Metastatic Squamous Cell Carcinoma of the Head and Neck: The Final Results of CheckMate 651.

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    PURPOSE: CheckMate 651 (ClinicalTrials.gov identifier: NCT02741570) evaluated first-line nivolumab plus ipilimumab versus EXTREME (cetuximab plus cisplatin/carboplatin plus fluorouracil ≤ six cycles, then cetuximab maintenance) in recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). METHODS: Patients without prior systemic therapy for R/M SCCHN were randomly assigned 1:1 to nivolumab plus ipilimumab or EXTREME. Primary end points were overall survival (OS) in the all randomly assigned and programmed death-ligand 1 combined positive score (CPS) ≥ 20 populations. Secondary end points included OS in the programmed death-ligand 1 CPS ≥ 1 population, and progression-free survival, objective response rate, and duration of response in the all randomly assigned and CPS ≥ 20 populations. RESULTS: Among 947 patients randomly assigned, 38.3% had CPS ≥ 20. There were no statistically significant differences in OS with nivolumab plus ipilimumab versus EXTREME in the all randomly assigned (median: 13.9 v 13.5 months; hazard ratio [HR], 0.95; 97.9% CI, 0.80 to 1.13; P = .4951) and CPS ≥ 20 (median: 17.6 v 14.6 months; HR, 0.78; 97.51% CI, 0.59 to 1.03; P = .0469) populations. In patients with CPS ≥ 1, the median OS was 15.7 versus 13.2 months (HR, 0.82; 95% CI, 0.69 to 0.97). Among patients with CPS ≥ 20, the median progression-free survival was 5.4 months (nivolumab plus ipilimumab) versus 7.0 months (EXTREME), objective response rate was 34.1% versus 36.0%, and median duration of response was 32.6 versus 7.0 months. Grade 3/4 treatment-related adverse events occurred in 28.2% of patients treated with nivolumab plus ipilimumab versus 70.7% treated with EXTREME. CONCLUSION: CheckMate 651 did not meet its primary end points of OS in the all randomly assigned or CPS ≥ 20 populations. Nivolumab plus ipilimumab showed a favorable safety profile compared with EXTREME. There continues to be a need for new therapies in patients with R/M SCCHN
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