19 research outputs found

    The role of resveratrol on skeletal muscle cell differentiation and myotube hypertrophy during glucose restriction

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    Glucose restriction (GR) impairs muscle cell differentiation and evokes myotube atrophy. Resveratrol treatment in skeletal muscle cells improves inflammatory-induced reductions in skeletal muscle cell differentiation. We therefore hypothesised that resveratrol treatment would improve muscle cell differentiation and myotube hypertrophy in differentiating C2C12 myoblasts and mature myotubes during GR. Glucose restriction at 0.6 g/L (3.3 mM) blocked differentiation and myotube hypertrophy versus high-glucose (4.5 g/L or 25 mM) differentiation media (DM) conditions universally used for myoblast culture. Resveratrol (10 μM) treatment increased SIRT1 phosphorylation in DM conditions, yet did not improve differentiation when administered to differentiating myoblasts in GR conditions. Resveratrol did evoke increases in hypertrophy of mature myotubes under DM conditions with corresponding elevated Igf-I and Myhc7 gene expression, coding for the ‘slow’ type I MYHC protein isoform. Inhibition of SIRT1 via EX-527 administration (100 nM) also reduced myotube diameter and area in DM conditions and resulted in lower gene expression of Myhc 1, 2 and 4 coding for ‘intermediate’ and ‘faster’ IIx, IIa and IIb protein isoforms, respectively. Resveratrol treatment did not appear to modulate phosphorylation of energy-sensing protein AMPK or protein translation initiator P70S6K. Importantly, in mature myotubes, resveratrol treatment was able to ameliorate reduced myotube growth in GR conditions over an acute 24-h period, but not over 48–72 h. Overall, resveratrol evoked myotube hypertrophy in DM conditions while favouring ‘slower’ Myhc gene expression and acutely ameliorated impaired myotube growth observed during glucose restriction

    A consensus guide to capturing the ability to inhibit actions and impulsive behaviors in the stop-signal task.

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    Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in some of these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our goal is to facilitate a more accurate use of the stop-signal task. To this end, we provide 12 easy-to-implement consensus recommendations and point out the problems that can arise when they are not followed. Furthermore, we provide user-friendly open-source resources intended to inform statistical-power considerations, facilitate the correct implementation of the task, and assist in proper data analysis

    Amorphism and Thermal Decomposition of Salicylsalicylic Acid - A Cautionary Tale

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    Salicylsalicylic acid (“Salsalate”) is a non-steroidal anti-inflammatory drug with anti-rheumatic properties, whose amorphous form offers the potential for enhanced dissolution rates and improved bioavailability compared with its crystalline counterpart. It has been reported to form a stable glassy phase on heating and rapid quenching. A number of the existing studies of the solid-state structure of salsalate and of its thermal decomposition contain information that is difficult to reconcile. In this article, we review much of the existing literature in light of our own recent studies using solution-state nuclear magnetic resonance, mass spectrometry, and solid-state infrared spectroscopy, and conclude that much of the literature data relating to melting and the glassy state is questionable due to failure to take into account the effects of thermal decomposition

    Flavonoid-based inhibitors of the Phi-class glutathione transferase from black-grass to combat multiple herbicide resistance

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    The evolution and growth of multiple-herbicide resistance (MHR) in grass weeds continues to threaten global cereal production. While various processes can contribute to resistance, earlier work has identified the phi class glutathione-S-transferase (AmGSTF1) as a functional biomarker of MHR in black-grass (Alopecurus myosuroides). This study provides further insights into the role of AmGSTF1 in MHR using a combination of chemical and structural biology. Crystal structures of wild-type AmGSTF1, together with two specifically designed variants that allowed the co-crystal structure determination with glutathione and a glutathione adduct of the AmGSTF1 inhibitor 4-chloro-7-nitro-benzofurazan (NBD-Cl) were obtained. These studies demonstrated that the inhibitory activity of NBD-Cl was associated with the occlusion of the active site and the impediment of substrate binding. A search for other selective inhibitors of AmGSTF1, using ligand-fishing experiments, identified a number of flavonoids as potential ligands. Subsequent experiments using black-grass extracts discovered a specific flavonoid as a natural ligand of the recombinant enzyme. A series of related synthetic flavonoids was prepared and their binding to AmGSTF1 was investigated showing a high affinity for derivatives bearing a O-5-decyl-α-carboxylate. Molecular modelling based on high-resolution crystal structures allowed a binding pose to be defined which explained flavonoid binding specificity. Crucially, high binding affinity was linked to a reversal of the herbicide resistance phenotype in MHR black-grass. Collectively, these results present a nature-inspired new lead for the development of herbicide synergists to counteract MHR in weeds

    Combined Modeling of US Fluvial, Pluvial, and Coastal Flood Hazard Under Current and Future Climates

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    This study reports a new and significantly enhanced analysis of US flood hazard at 30 m spatial resolution. Specific improvements include updated hydrography data, new methods to determine channel depth, more rigorous flood frequency analysis, output downscaling to property tract level, and inclusion of the impact of local interventions in the flooding system. For the first time, we consider pluvial, fluvial, and coastal flood hazards within the same framework and provide projections for both current (rather than historic average) conditions and for future time periods centered on 2035 and 2050 under the RCP4.5 emissions pathway. Validation against high-quality local models and the entire catalog of FEMA 1% annual probability flood maps yielded Critical Success Index values in the range 0.69–0.82. Significant improvements over a previous pluvial/fluvial model version are shown for high-frequency events and coastal zones, along with minor improvements in areas where model performance was already good. The result is the first comprehensive and consistent national-scale analysis of flood hazard for the conterminous US for both current and future conditions. Even though we consider a stabilization emissions scenario and a near-future time horizon, we project clear patterns of changing flood hazard (3σ changes in 100 years inundated area of −3.8 to +16% at 1° scale), that are significant when considered as a proportion of the land area where human use is possible or in terms of the currently protected land area where the standard of flood defense protection may become compromised by this time

    Patterns of Recurrence After Resection of Pancreatic Ductal Adenocarcinoma: A Secondary Analysis of the ESPAC-4 Randomized Adjuvant Chemotherapy Trial

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    Importance: The patterns of disease recurrence after resection of pancreatic ductal adenocarcinoma with adjuvant chemotherapy remain unclear. Objective: To define patterns of recurrence after adjuvant chemotherapy and the association with survival. Design, Setting, and Participants: Prospectively collected data from the phase 3 European Study Group for Pancreatic Cancer 4 adjuvant clinical trial, an international multicenter study. The study included 730 patients who had resection and adjuvant chemotherapy for pancreatic cancer. Data were analyzed between July 2017 and May 2019. Interventions: Randomization to adjuvant gemcitabine or gemcitabine plus capecitabine. Main Outcomes and Measures: Overall survival, recurrence, and sites of recurrence. Results: Of the 730 patients, median age was 65 years (range 37-81 years), 414 were men (57%), and 316 were women (43%). The median follow-up time from randomization was 43.2 months (95% CI, 39.7-45.5 months), with overall survival from time of surgery of 27.9 months (95% CI, 24.8-29.9 months) with gemcitabine and 30.2 months (95% CI, 25.8-33.5 months) with the combination (HR, 0.81; 95% CI, 0.68-0.98; P = .03). The 5-year survival estimates were 17.1% (95% CI, 11.6%-23.5%) and 28.0% (22.0%-34.3%), respectively. Recurrence occurred in 479 patients (65.6%); another 78 patients (10.7%) died without recurrence. Local recurrence occurred at a median of 11.63 months (95% CI, 10.05-12.19 months), significantly different from those with distant recurrence with a median of 9.49 months (95% CI, 8.44-10.71 months) (HR, 1.21; 95% CI, 1.01-1.45; P = .04). Following recurrence, the median survival was 9.36 months (95% CI, 8.08-10.48 months) for local recurrence and 8.94 months (95% CI, 7.82-11.17 months) with distant recurrence (HR, 0.89; 95% CI, 0.73-1.09; P = .27). The median overall survival of patients with distant-only recurrence (23.03 months; 95% CI, 19.55-25.85 months) or local with distant recurrence (23.82 months; 95% CI, 17.48-28.32 months) was not significantly different from those with only local recurrence (24.83 months; 95% CI, 22.96-27.63 months) (P = .85 and P = .35, respectively). Gemcitabine plus capecitabine had a 21% reduction of death following recurrence compared with monotherapy (HR, 0.79; 95% CI, 0.64-0.98; P = .03). Conclusions and Relevance: There were no significant differences between the time to recurrence and subsequent and overall survival between local and distant recurrence. Pancreatic cancer behaves as a systemic disease requiring effective systemic therapy after resection. Trial Registration: Clinicaltrials.gov Identifier: NCT00058201, EudraCT 2007-004299-38, and ISRCTN 96397434
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