Small molecule binding to surface-supported single-site transition-metal reaction centres.

Despite dominating industrial processes, heterogeneous catalysts remain challenging to characterize and control. This is largely attributable to the diversity of potentially active sites at the catalyst-reactant interface and the complex behaviour that can arise from interactions between active sites. Surface-supported, single-site molecular catalysts aim to bring together benefits of both heterogeneous and homogeneous catalysts, offering easy separability while exploiting molecular design of reactivity, though the presence of a surface is likely to influence reaction mechanisms. Here, we use metal-organic coordination to build reactive Fe-terpyridine sites on the Ag(111) surface and study their activity towards CO and C2H4 gaseous reactants using low-temperature ultrahigh-vacuum scanning tunnelling microscopy, scanning tunnelling spectroscopy, and atomic force microscopy supported by density-functional theory models. Using a site-by-site approach at low temperature to visualize the reaction pathway, we find that reactants bond to the Fe-tpy active sites via surface-bound intermediates, and investigate the role of the substrate in understanding and designing single-site catalysts on metallic supports.

Active Ornstein-Uhlenbeck model for self-propelled particles with inertia.

Self-propelled particles, which convert energy into mechanical motion, exhibit inertia if they have a macroscopic size or move inside a gaseous medium, in contrast to micron-sized overdamped particles immersed in a viscous fluid. Here we study an extension of the active Ornstein-Uhlenbeck model, in which self-propulsion is described by colored noise, to access these inertial effects. We summarize and discuss analytical solutions of the particle's mean-squared displacement and velocity autocorrelation function for several settings ranging from a free particle to various external influences, like a linear or harmonic potential and coupling to another particle via a harmonic spring. Taking into account the particular role of the initial particle velocity in a nonstationary setup, we observe all dynamical exponents between zero and four. After the typical inertial time, determined by the particle's mass, the results inherently revert to the behavior of an overdamped particle with the exception of the harmonically confined systems, in which the overall displacement is enhanced by inertia. We further consider an underdamped model for an active particle with a time-dependent mass, which critically affects the displacement in the intermediate time-regime. Most strikingly, for a sufficiently large rate of mass accumulation, the particle's motion is completely governed by inertial effects as it remains superdiffusive for all times.

Early local activation of complement in aqueous humour of patients with age-related macular degeneration.

OBJECTIVE: To investigate complement activation in aqueous humour of patients with early, intermediate and neovascular age-related macular degeneration (AMD). PATIENTS AND METHODS: Aqueous humour of 79 AMD patients (early, intermediate and neovascular) and 77 age-matched controls was prospectively collected. The levels of the complement protein 3 (C3), activation products complement factor 3a (C3a) and Ba, C3b/iC3b, complement factors B, H and I (CFB, CFH and CFI), and total protein concentration were measured. Data were modelled using covariate analysis to assess the impact of age and glaucoma status of patients and total protein concentration of samples on complement protein concentration across groups. RESULTS: C3a concentration was significantly increased in the aqueous humour of early (p = 0.016), intermediate (p = 0.003) and neovascular (p = 0.018) AMD patients, whilst C3 concentration was significantly increased in early AMD patients only (p = 0.019). Levels of CFB and CFH were significantly increased in the aqueous humour of neovascular AMD patients (p = 0.023 and p = 0.018, respectively). CONCLUSIONS: Our findings provide evidence for early local complement dysregulation in AMD patients, suggesting that complement pathway inhibition may be a clinically relevant intervention for early stages of AMD.

Use of neuromuscular blocking agents in acute respiratory distress syndrome.

Acute respiratory distress syndrome is the result of an acute inflammatory response of the lungs, causing severe hypoxemia. A variety of therapeutic modalities have been extensively studied, with only a few demonstrating improvement in survival. Specifically, mechanical ventilation with use of low tidal volumes, prone positioning, and treatment with neuromuscular blocking agents have proven beneficial. This article focuses on the utilization of neuromuscular blocking agents in this entity. In particular, we briefly review the mechanism of action of neuromuscular blockades, the latest published evidence supporting their use in acute respiratory distress syndrome, and current recommendations for their utilization in clinical practice.

Novel factor VIII variants with a modified furin cleavage site improve the efficacy of gene therapy for hemophilia A.

Essentials Factor (F) VIII is an inefficiently expressed protein. Furin deletion FVIII variants were purified and characterized using in vitro and in vivo assays. These minimally modified novel FVIII variants have enhanced function. These variants provide a strategy for increasing FVIII expression in hemophilia A gene therapy. SUMMARY: Background The major challenge for developing gene-based therapies for hemophilia A is that human factor VIII (hFVIII) has intrinsic properties that result in inefficient biosynthesis. During intracellular processing, hFVIII is predominantly cleaved at a paired basic amino acid cleaving enzyme (PACE) or furin cleavage site to yield a heterodimer that is the major form of secreted protein. Previous studies with B-domain-deleted (BDD) canine FVIII and hFVIII-R1645H, both differing from hFVIII by a single amino acid at this site, suggested that these proteins are secreted mainly in a single polypeptide chain (SC) form and exhibit enhanced function. Objective We hypothesized that deletion(s) of the furin site modulates FVIII biology and may enhance its function. Methods A series of recombinant hFVIII-furin deletion variants were introduced into hFVIII-BDD [Δ1645, 1645-46(Δ2), 1645-47(Δ3), 1645-48(Δ4), or Δ1648] and characterized. Results In vitro, recombinant purified Δ3 and Δ4 were primarily SC and, interestingly, had 2-fold higher procoagulant activity compared with FVIII-BDD. In vivo, the variants also have improved hemostatic function. After adeno-associated viral (AAV) vector delivery, the expression of these variants is 2-4-fold higher than hFVIII-BDD. Protein challenges of each variant in mice tolerant to hFVIII-BDD showed no anti-FVIII immune response. Conclusions These data suggest that the furin deletion hFVIII variants are superior to hFVIII-BDD without increased immunogenicity. In the setting of gene-based therapeutics, these novel variants provide a unique strategy to increase FVIII expression, thus lowering the vector dose, a critical factor for hemophilia A gene therapy.

An RNA interference screen identifies new avenues for nephroprotection.

This corrects the article DOI: 10.1038/cdd.2015.128.

Chalcone-based Selective Inhibitors of a C4 Plant Key Enzyme as Novel Potential Herbicides.

Weeds are a challenge for global food production due to their rapidly evolving resistance against herbicides. We have identified chalcones as selective inhibitors of phosphoenolpyruvate carboxylase (PEPC), a key enzyme for carbon fixation and biomass increase in the C4 photosynthetic pathway of many of the world's most damaging weeds. In contrast, many of the most important crop plants use C3 photosynthesis. Here, we show that 2',3',4',3,4-Pentahydroxychalcone (IC50 = 600 nM) and 2',3',4'-Trihydroxychalcone (IC50 = 4.2 µM) are potent inhibitors of C4 PEPC but do not affect C3 PEPC at a same concentration range (selectivity factor: 15-45). Binding and modeling studies indicate that the active compounds bind at the same site as malate/aspartate, the natural feedback inhibitors of the C4 pathway. At the whole plant level, both substances showed pronounced growth-inhibitory effects on the C4 weed Amaranthus retroflexus, while there were no measurable effects on oilseed rape, a C3 plant. Growth of selected soil bacteria was not affected by these substances. Our chalcone compounds are the most potent and selective C4 PEPC inhibitors known to date. They offer a novel approach to combat C4 weeds based on a hitherto unexplored mode of allosteric inhibition of a C4 plant key enzyme.

Iron Deficiency, Zinc, Magnesium, Vitamin Deficiencies in Crohn's Disease: Substitute or Not?

Inflammatory bowel disease (IBD) is characterized by inflammatory reactions, complications, extraintestinal manifestations and a loss of intestinal functions, for example, failures of absorption and secretion. According to intestinal dysfunction, a wide array of pathogenetic pathways is existing leading to iron deficiency and numerous vitamins as well as trace element deficiencies. Complications, symptoms and signs of those deficiencies are common in IBD with varying degrees of clinical significance. This review focuses on selected micronutrients including iron, zinc, magnesium and some vitamins. Epidemiology with respect to IBD, pathophysiology, diagnosis and clinical aspects are addressed. Finally, some suggestions for treatment of deficient situations are discussed. In conclusion, some micronutrients have significant impact on complications and quality of life in IBD. Deficiencies may even influence the course of the disease. Those deficiencies should be thoroughly supplemented.

Clostridium difficile associated risk of death score (CARDS): a novel severity score to predict mortality among hospitalised patients with C. difficile infection.

BACKGROUND: Clostridium difficile infection (CDI) is a public health threat and associated with significant mortality. However, there is a paucity of objectively derived CDI severity scoring systems to predict mortality. AIM: To develop a novel CDI risk score to predict mortality entitled: Clostridium difficile associated risk of death score (CARDS). METHODS: We obtained data from the United States 2011 Nationwide Inpatient Sample (NIS) database. All CDI-associated hospitalisations were identified using discharge codes (ICD-9-CM, 008.45). Multivariate logistic regression was utilised to identify independent predictors of mortality. Clostridium difficile associated risk of death score was calculated by assigning a numeric weight to each parameter based on their odds ratio in the final logistic model. Predictive properties of model discrimination were assessed using the c-statistic and validated in an independent sample using the 2010 NIS database. RESULTS: We identified 77 776 hospitalisations, yielding an estimate of 374 747 cases with an associated diagnosis of CDI in the US, 8% of whom died in the hospital. The eight severity score predictors were identified on multivariate analysis: age, cardiopulmonary disease, malignancy, diabetes, inflammatory bowel disease, acute renal failure, liver disease and ICU admission, with weights ranging from -1 (for diabetes) to 5 (for ICU admission). The overall risk score in the cohort ranged from 0 to 18. Mortality increased significantly as CARDS increased. CDI-associated mortality was 1.2% with a CARDS of 0 compared to 100% with CARDS of 18. The model performed equally well in our validation cohort. CONCLUSION: Clostridium difficile associated risk of death score is a promising simple severity score to predict mortality among those hospitalised with C. difficile infection.

Evaluation of the efficacy and tolerance of a short 7 day third-generation cephalosporin treatment in the management of acute pyelonephritis in young women in the emergency department.

OBJECTIVES: Urinary tract infections, among the leading causes of antibiotic prescriptions in adult women, are complicated by increasing antibiotic resistance. Current recommendations propose a 7 day treatment with fluoroquinolones or a 10-14 day course of third-generation cephalosporins (3GC). Our aim was to study the efficiency and tolerance of a short 7 day treatment with 3GC in uncomplicated acute pyelonephritis in women aged between 18 and 65 years. PATIENTS AND METHODS: This study was an open, prospective, non-comparative, monocentric pilot study with consecutive patients. We included women between 18 and 65 years old who had been admitted to the emergency department with a diagnosis of acute pyelonephritis. The treatment consisted of 1 g of ceftriaxone injection followed by 6 days of 400 mg of cefixime per day. The primary endpoint was negative urine cultures on day 9. We opted for Fleming's multistage design for this trial. ClinicalTrials.gov number: NCT01390623. RESULTS: Thirty-seven patients were analysed. The bacteriological response consisted of negative urine cultures for all 37 patients on day 9. On day 9, 30 patients were completely asymptomatic, while 7 exhibited clinical improvement though persistence of bladder irritation or flank pain. On day 37, there were no remaining symptoms and no recurrences of urinary tract infection, as noted during the last follow-up visits. CONCLUSIONS: These results suggest that acute pyelonephritis in women could be successfully treated with a short-term course of 1 g of ceftriaxone on the first day followed by 400 mg of cefixime per day for 6 days. These positive results must be confirmed by a non-inferiority study.

Higher Adalimumab Drug Levels are Associated with Mucosal Healing in Patients with Crohn's Disease.

BACKGROUND AND AIMS: The current approach to managing the loss of response to anti-tumour necrosis factor (TNF) agents is generally empirical. Prior studies have suggested that adalimumab levels of >4.9 µg/mL are required to achieve clinical remission. Our aim was to identify an optimal adalimumab level to achieve endoscopic healing in Crohn's disease (CD). METHODS: A cohort of 60 CD patients treated with adalimumab between 2005 and 2013 were reviewed for the study. Demographic and clinical information was obtained from chart review and patient interview. Disease activity was determined using the Harvey-Bradshaw index (HBI), ileocolonoscopy reports and C-reactive protein (CRP) levels. Clinical remission was defined as HBI <5. Endoscopic remission/mucosal healing (MH) was defined as the absence of any ulceration in all ileocolonic segments. Trough adalimumab levels and adalimumab antibody levels were tested using a liquid-phase mobility shift assay. RESULTS: Lower median CRP was significantly associated with MH 1.2mg/dl vs no MH 14.4mg/dl (p = 6.93×10(-6)). Higher adalimumab trough level was significantly associated with MH (median 14.7 µg/mL in those with MH vs 3.4 µg/mL in those without, p = 6.25×10(-5)). Higher adalimumab trough level was also significantly associated with the combined outcome of clinical and endoscopic remission (median 13.0 vs 4.8 µg/mL, p = 5.36×10(-3)). A cut-off of 8.14 µg/ml best discriminated subjects with MH from those without MH, with sensitivity and specificity of 91.4 and 76.0%, respectively (positive and negative predictive values 84.2 and 86.4%, respectively). CONCLUSIONS: Higher adalimumab levels were significantly associated with MH. This study suggests that attaining MH alone or a combined outcome of clinical and endoscopic remission is more likely to occur in those patients who achieve an adalimumab trough level of at least 8.14 µg/mL.

American Gastroenterological Association Institute Guideline on the Medical Management of Microscopic Colitis

This article has an accompanying continuing medical education activity on page e17. Learning Objective: Upon completion of this test, successful learners will be able to: (1) learn first-line treatment for the induction of remission in microscopic colitis; (2) identify the expected clinical benefi ts and adverse effects of induction therapy for microscopic colitis; (3) understand the in-dications for and dosing of maintenance therapy for microscopic colitis; (4) consider medications that may precipitate microscopic colitis especially in those who are refractory to medical therapy; and (5) become familiar with treatment strategies for microscopic colitis refractory to first-line therapy.

An RNA interference screen identifies new avenues for nephroprotection.

Acute kidney injury is a major public health problem, which is commonly caused by renal ischemia and is associated with a high risk of mortality and long-term disability. Efforts to develop a treatment for this condition have met with very limited success. We used an RNA interference screen to identify genes (BCL2L14, BLOC1S2, C2ORF42, CPT1A, FBP1, GCNT3, RHOB, SCIN, TACR1, and TNFAIP6) whose suppression improves survival of kidney epithelial cells in in vitro models of oxygen and glucose deprivation. Some of the genes also modulate the toxicity of cisplatin, an anticancer agent whose use is currently limited by nephrotoxicity. Furthermore, pharmacological inhibition of TACR1 product NK1R was protective in a model of mouse renal ischemia, attesting to the in vivo relevance of our findings. These data shed new light on the mechanisms of stress response in mammalian cells, and open new avenues to reduce the morbidity and mortality associated with renal injury.

Gene expression of INPP5F as an independent prognostic marker in fludarabine-based therapy of chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a heterogeneous disease. Various disease-related and patient-related factors have been shown to influence the course of the disease. The aim of this study was to identify novel biomarkers of significant clinical relevance. Pretreatment CD19-separated lymphocytes (n=237; discovery set) and peripheral blood mononuclear cells (n=92; validation set) from the REACH trial, a randomized phase III trial in relapsed CLL comparing rituximab plus fludarabine plus cyclophosphamide with fludarabine plus cyclophosphamide alone, underwent gene expression profiling. By using Cox regression survival analysis on the discovery set, we identified inositol polyphosphate-5-phosphatase F (INPP5F) as a prognostic factor for progression-free survival (P<0.001; hazard ratio (HR), 1.63; 95% confidence interval (CI), 1.35-1.98) and overall survival (P<0.001; HR, 1.47; 95% CI, 1.18-1.84), regardless of adjusting for known prognostic factors. These findings were confirmed on the validation set, suggesting that INPP5F may serve as a novel, easy-to-assess future prognostic biomarker for fludarabine-based therapy in CLL.

Reciprocal encoding of signal intensity and duration in a glucose-sensing circuit.

Cells continuously adjust their behavior in response to changing environmental conditions. Both intensity and duration of external signals are critical factors in determining what response is initiated. To understand how intracellular signaling networks process such multidimensional information, we studied the AtRGS1-mediated glucose response system of Arabidopsis. By combining experiments with mathematical modeling, we discovered a reciprocal dose and duration response relying on the orchestrated action of three kinases (AtWNK1, AtWNK8, and AtWNK10) acting on distinct timescales and activation thresholds. Specifically, we find that high concentrations of D-glucose rapidly signal through AtWNK8 and AtWNK10, whereas low, sustained sugar concentration slowly activate the pathway through AtWNK1, allowing the cells to respond similarly to transient, high-intensity signals and sustained, low-intensity signals. This "dose-duration reciprocity" allows encoding of both the intensity and persistence of glucose as an important energy resource and signaling molecule.

Rectification properties of conically shaped nanopores: consequences of miniaturization.

Nanopores attracted a great deal of scientific interest as templates for biological sensors as well as model systems to understand transport phenomena at the nanoscale. The experimental and theoretical analysis of nanopores has been so far focused on understanding the effect of the pore opening diameter on ionic transport. In this article we present systematic studies on the dependence of ion transport properties on the pore length. Particular attention was given to the effect of ion current rectification exhibited in conically shaped nanopores with homogeneous surface charges. We found that reducing the length of conically shaped nanopores significantly lowered their ability to rectify ion current. However, rectification properties of short pores can be enhanced by tailoring the surface charge and the shape of the narrow opening. Furthermore we analyzed the relationship of the rectification behavior and ion selectivity for different pore lengths. All simulations were performed using MsSimPore, a software package for solving the Poisson-Nernst-Planck (PNP) equations. It is based on a novel finite element solver and allows for simulations up to surface charge densities of -2 e per nm(2). MsSimPore is based on 1D reduction of the PNP model, but allows for a direct treatment of the pore with bulk electrolyte reservoirs, a feature which was previously used in higher dimensional models only. MsSimPore includes these reservoirs in the calculations, a property especially important for short pores, where the ionic concentrations and the electric potential vary strongly inside the pore as well as in the regions next to the pore entrance.

Impact of Clostridium difficile colitis on 5-year health outcomes in patients with ulcerative colitis.

BACKGROUND: Clostridium difficile colitis (CDC) is associated with an increased short-term mortality risk in hospitalised ulcerative colitis (UC) patients. We sought to determine whether CDC also impacts long-term risks of adverse health events in this population. AIM: To determine whether CDC also impacts long-term risks of adverse health events in this population. METHODS: A population-based retrospective cohort study was conducted of UC patients hospitalised in Ontario, Canada between 2002 and 2008. Patients with and without CDC were compared on the rates of adverse health events. The primary outcomes were the 5-year adjusted risks of colectomy and death. RESULTS: Among 181 patients with CDC and 1835 patients without CDC, the 5-year cumulative colectomy rates were 44% and 33% (P = 0.0052) and the 5-year cumulative mortality rates were 27% and 14% (P < 0.0001) respectively. CDC was associated with a higher adjusted 5-year risk of mortality [adjusted hazard ratio (aHR) 2.40, 95% CI 1.37-4.20], but not of colectomy (aHR 1.18, 95% CI 0.90-1.54). CDC impacted mortality risk both during index hospitalisation (adjusted odds ratio 8.90, 95% CI 2.80-28.3) as well as over 5 years following hospital discharge among patients who recovered from their acute illness (aHR 2.41, 95% CI 1.37-4.22). Colectomy risk was not influenced by CDC in this cohort. CONCLUSION: Clostridium difficile colitis is associated with increased short-term and long-term mortality risks among hospitalised ulcerative colitis patients. As colectomy risk is not similarly impacted by Clostridium difficile colitis, factors predictive of death among C. difficile-infected ulcerative colitis patients require elucidation.