370 research outputs found
Cowbane, Oxypolis occidentalis, A New Native Vascular Plant Species for the Queen Charlotte Islands, British Columbia
We report the recent discovery of Oxypolis occidentalis, a species that is new to both British Columbia and Canada, disjunct on the Queen Charlotte Islands
Protonation state of glutamate 73 regulates the formation of a specific dimeric association of mVDAC1.
The voltage-dependent anion channel (VDAC) is the most abundant protein in the outer mitochondrial membrane and constitutes the primary pathway for the exchange of ions and metabolites between the cytosol and the mitochondria. There is accumulating evidence supporting VDAC's role in mitochondrial metabolic regulation and apoptosis, where VDAC oligomerization has been implicated with these processes. Herein, we report a specific pH-dependent dimerization of murine VDAC1 (mVDAC1) identified by double electron-electron resonance and native mass spectrometry. Intermolecular distances on four singly spin-labeled mVDAC1 mutants were used to generate a model of the low-pH dimer, establishing the presence of residue E73 at the interface. This dimer arrangement is different from any oligomeric state previously described, and it forms as a steep function of pH with an apparent pKa of 7.4. Moreover, the monomer-dimer equilibrium affinity constant was determined using native MS, revealing a nearly eightfold enhancement in dimerization affinity at low pH. Mutation of E73 to either alanine or glutamine severely reduces oligomerization, demonstrating the role of protonated E73 in enhancing dimer formation. Based on these results, and the known importance of E73 in VDAC physiology, VDAC dimerization likely plays a significant role in mitochondrial metabolic regulation and apoptosis in response to cytosolic acidification during cellular stress
Hedgehog pathway dysregulation contributes to the pathogenesis of human gastrointestinal stromal tumors via GLI-mediated activation of KIT expression.
Gastrointestinal stromal tumors (GIST) arise within the interstitial cell of Cajal (ICC) lineage due to activating KIT/PDGFRA mutations. Both ICC and GIST possess primary cilia (PC), which coordinate PDGFRA and Hedgehog signaling, regulators of gastrointestinal mesenchymal development. Therefore, we hypothesized that Hedgehog signaling may be altered in human GIST and controls KIT expression. Quantitative RT-PCR, microarrays, and next generation sequencing were used to describe Hedgehog/PC-related genes in purified human ICC and GIST. Genetic and pharmacologic approaches were employed to investigate the effects of GLI manipulation on KIT expression and GIST cell viability. We report that Hedgehog pathway and PC components are expressed in ICC and GIST and subject to dysregulation during GIST oncogenesis, irrespective of KIT/PDGFRA mutation status. Using genomic profiling, 10.2% of 186 GIST studied had potentially deleterious genomic alterations in 5 Hedgehog-related genes analyzed, including in the PTCH1 tumor suppressor (1.6%). Expression of the predominantly repressive GLI isoform, GLI3, was inversely correlated with KIT mRNA levels in GIST cells and non-KIT/non-PDGFRA mutant GIST. Overexpression of the 83-kDa repressive form of GLI3 or small interfering RNA-mediated knockdown of the activating isoforms GLI1/2 reduced KIT mRNA. Treatment with GLI1/2 inhibitors, including arsenic trioxide, significantly increased GLI3 binding to the KIT promoter, decreased KIT expression, and reduced viability in imatinib-sensitive and imatinib-resistant GIST cells. These data offer new evidence that genes necessary for Hedgehog signaling and PC function in ICC are dysregulated in GIST. Hedgehog signaling activates KIT expression irrespective of mutation status, offering a novel approach to treat imatinib-resistant GIST
School-based education programmes for the prevention of unintentional injuries in children and young people.
Background: Unintentional injuries are the leading cause of death in children aged four to 18 years and are a major cause of ill health. The school setting offers the opportunity to deliver preventive interventions to a large number of children and has been used to address a range of public health problems. However, the effectiveness of the school setting for the prevention of different injury mechanisms in school-aged children is not well understood.
Objectives: To assess the effects of school-based educational programmes for the prevention of injuries in children and evaluate their impact on improving children's safety skills, behaviour and practices, and knowledge, and assess their cost-effectiveness.
Search methods: We ran the most recent searches up to 16 September 2016 for the following electronic databases: Cochrane Injuries Group Specialised Register; Cochrane Central Register of Controlled Trials; Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations; Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R); Embase and Embase Classic (Ovid); ISI Web of Science: Science Citation Index Expanded; ISI Web of Science Conference Proceedings Citation Index-Science; ISI Web of Science: Social Sciences Citation Index; ISI Web of Science: Conference Proceedings Citation Index - Social Sciences & Humanities; and the 14 October 2016 for the following electronic databases: Health Economics Evaluations Database (HEED); Health Technology Assessment Database (HTA); CINAHL Plus (EBSCO); ZETOC; LILACS; PsycINFO; ERIC; Dissertation Abstracts Online; IBSS; BEI; ASSIA; CSA Sociological Abstracts; Injury Prevention Web; SafetyLit; EconLit (US); PAIS; UK Clinical Research Network Study Portfolio; Open Grey; Index to Theses in the UK and Ireland; Bibliomap and TRoPHI.
Selection criteria: We included randomised controlled trials (RCTs), non-randomised controlled trials (non-RCTs), and controlled before-and-after (CBA) studies that evaluated school-based educational programmes aimed at preventing a range of injury mechanisms. The primary outcome was self-reported or medically attended unintentional (or unspecified intent) injuries and secondary outcomes were observed safety skills, observed behaviour, self-reported behaviour and safety practices, safety knowledge, and health economic outcomes. The control groups received no intervention, a delayed injury-prevention intervention or alternative school-based curricular activities. We included studies that aimed interventions at primary or secondary prevention of injuries from more than one injury mechanism and were delivered, in part or in full, in schools catering for children aged four to 18 years.
Data collection and analysis: We used standard methodological procedures expected by Cochrane. Two review authors identified relevant trials from title and abstracts of studies identified in searches and two review authors extracted data from the included studies and assessed risk of bias. We grouped different types of interventions according to the outcome assessed and the injury mechanism targeted. Where data permitted, we performed random-effects meta-analyses to provide a summary of results across studies.
Main results: The review included 27 studies reported in 30 articles. The studies had 73,557 participants with 12 studies from the US; four from China; two from each of Australia, Canada, the Netherlands and the UK; and one from each of Israel, Greece and Brazil. Thirteen studies were RCTs, six were non-RCTs and eight were CBAs. Of the included studies, 18 provided some element of the intervention in children aged four to 11 years, 17 studies included children aged 11 to 14 years and nine studies included children aged 14 to 18 years.
The overall quality of the results was poor, with the all studies assessed as being at high or unclear risks of bias across multiple domains, and varied interventions and data collection methods employed. Interventions comprised information-giving, peer education or were multi-component.
Seven studies reported the primary outcome of injury occurrence and only three of these were similar enough to combine in a meta-analysis, with a pooled incidence rate ratio of 0.73 (95% confidence interval (CI) 0.49 to 1.08; 2073 children) and substantial statistical heterogeneity (I2 = 63%). However, this body of evidence was low certainty, due to concerns over this heterogeneity (inconsistency) and imprecision. This heterogeneity may be explained by the non-RCT study design of one of the studies, as a sensitivity analysis with this study removed found stronger evidence of an effect and no heterogeneity (I2 = 0%).
Two studies report an improvement in safety skills in the intervention group. Likewise, the four studies measuring observed safety behaviour reported an improvement in the intervention group relative to the control. Thirteen out of 19 studies describing self-reported behaviour and safety practices showed improvements, and of the 21 studies assessing changes in safety knowledge, 19 reported an improvement in at least one question domain in the intervention compared to the control group. However, we were unable to pool data for our secondary outcomes, so our conclusions were limited, as they were drawn from highly diverse single studies and the body of evidence was low (safety skills) or very low (behaviour, safety knowledge) certainty. Only one study reported intervention costs but did not undertake a full economic evaluation (very low certainty evidence).
Authors' conclusions: There is insufficient evidence to determine whether school-based educational programmes can prevent unintentional injuries. More high-quality studies are needed to evaluate the impact of educational programmes on injury occurrence. There is some weak evidence that such programmes improve safety skills, behaviour/practices and knowledge, although the evidence was of low or very low quality certainty. We found insufficient economic studies to assess cost-effectiveness
Perception versus reality: A National Cohort Analysis of the surgery-first approach for resectable pancreatic cancer
INTRODUCTION: Although surgical resection is necessary, it is not sufficient for long-term survival in pancreatic ductal adenocarcinoma (PDAC). We sought to evaluate survival after up-front surgery (UFS) in anatomically resectable PDAC in the context of three critical factors: (A) margin status; (B) CA19-9; and (C) receipt of adjuvant chemotherapy.
METHODS: The National Cancer Data Base (2010-2015) was reviewed for clinically resectable (stage 0/I/II) PDAC patients. Surgical margins, pre-operative CA19-9, and receipt of adjuvant chemotherapy were evaluated. Patient overall survival was stratified based on these factors and their respective combinations. Outcomes after UFS were compared to equivalently staged patients after neoadjuvant chemotherapy on an intention-to-treat (ITT) basis.
RESULTS: Twelve thousand and eighty-nine patients were included (n = 9197 UFS, n = 2892 ITT neoadjuvant). In the UFS cohort, only 20.4% had all three factors (median OS = 31.2 months). Nearly 1/3rd (32.7%) of UFS patients had none or only one factor with concomitant worst survival (median OS = 14.7 months). Survival after UFS decreased with each failing factor (two factors: 23 months, one factor: 15.5 months, no factors: 7.9 months) and this persisted after adjustment. Overall survival was superior in the ITT-neoadjuvant cohort (27.9 vs. 22 months) to UFS.
CONCLUSION: Despite the perceived benefit of UFS, only 1-in-5 UFS patients actually realize maximal survival when known factors highly associated with outcomes are assessed. Patients are proportionally more likely to do worst, rather than best after UFS treatment. Similarly staged patients undergoing ITT-neoadjuvant therapy achieve survival superior to the majority of UFS patients. Patients and providers should be aware of the false perception of \u27optimal\u27 survival benefit with UFS in anatomically resectable PDAC
New Crayfish Species Records from the Sipsey Fork Drainage, Including Lewis Smith Reservoir (Alabama, USA): Native or Introduced Species?
As part of a study of aquatic faunal community changes along riverine-lacustrine transition zones upstream of Lewis Smith Reservoir in northwest Alabama, USA, we collected crayfish from 60 sites in the Sipsey Fork, Brushy Creek, and selected tributaries (Black Warrior River system). After finding two unexpected and possibly-introduced crayfish species, we expanded our investigation of crayfish distributions to include crayfish obtained from stomachs of black bass ( Micropterus spp.) caught at seven sites in the reservoir. To explore what crayfish species were in the drainage historically, we examined museum databases as well as stomach and intestinal contents of a variety of preserved fishes that were caught in the Sipsey Fork and Brushy Creek drainages upstream of the reservoir in the early 1990’s. Of the seven crayfish species collected, one, Orconectes ( Procericambarus ) sp. nr ronaldi , was not previously reported from Alabama, and another, O. lancifer , was not reported from the Black Warrior River system prior to the study. Three are known or possibly introduced species. Upstream of the reservoir, the native species Cambarus obstipus, C. striatus , and O. validus were common. The same three species were found in fish collected in the 1990’s. Orconectes perfectus was found only in the reservoir but may be native to the drainage. Orconectes lancifer was in the reservoir and in stream reaches influenced by the reservoir. Evidence points to O. lancifer being introduced in the drainage, but this is uncertain. Orconectes sp. nr ronaldi was found in a relatively small portion of Brushy Creek and its tributaries, in both flowing and impounded habitats, and may be introduced. Orconectes virilis is introduced in Alabama and was found only in stomachs of fish collected in the reservoir
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Membrane-To-Nucleus Signaling Links Insulin-Like Growth Factor-1- and Stem Cell Factor-Activated Pathways
Stem cell factor (mouse: Kitl, human: KITLG) and insulin-like growth factor-1 (IGF1), acting via KIT and IGF1 receptor (IGF1R), respectively, are critical for the development and integrity of several tissues. Autocrine/paracrine KITLG-KIT and IGF1-IGF1R signaling are also activated in several cancers including gastrointestinal stromal tumors (GIST), the most common sarcoma. In murine gastric muscles, IGF1 promotes Kitl-dependent development of interstitial cells of Cajal (ICC), the non-neoplastic counterpart of GIST, suggesting cooperation between these pathways. Here, we report a novel mechanism linking IGF1-IGF1R and KITLG-KIT signaling in both normal and neoplastic cells. In murine gastric muscles, the microenvironment for ICC and GIST, human hepatic stellate cells (LX-2), a model for cancer niches, and GIST cells, IGF1 stimulated Kitl/KITLG protein and mRNA expression and promoter activity by activating several signaling pathways including AKT-mediated glycogen synthase kinase-3β inhibition (GSK3i). GSK3i alone also stimulated Kitl/KITLG expression without activating mitogenic pathways. Both IGF1 and GSK3i induced chromatin-level changes favoring transcriptional activation at the Kitl promoter including increased histone H3/H4 acetylation and H3 lysine (K) 4 methylation, reduced H3K9 and H3K27 methylation and reduced occupancy by the H3K27 methyltransferase EZH2. By pharmacological or RNA interference-mediated inhibition of chromatin modifiers we demonstrated that these changes have the predicted impact on KITLG expression. KITLG knock-down and immunoneutralization inhibited the proliferation of GIST cells expressing wild-type KIT, signifying oncogenic autocrine/paracrine KITLG-KIT signaling. We conclude that membrane-to-nucleus signaling involving GSK3i establishes a previously unrecognized link between the IGF1-IGF1R and KITLG-KIT pathways, which is active in both physiologic and oncogenic contexts and can be exploited for therapeutic purposes
Genetic determinants of co-accessible chromatin regions in activated T cells across humans.
Over 90% of genetic variants associated with complex human traits map to non-coding regions, but little is understood about how they modulate gene regulation in health and disease. One possible mechanism is that genetic variants affect the activity of one or more cis-regulatory elements leading to gene expression variation in specific cell types. To identify such cases, we analyzed ATAC-seq and RNA-seq profiles from stimulated primary CD4+ T cells in up to 105 healthy donors. We found that regions of accessible chromatin (ATAC-peaks) are co-accessible at kilobase and megabase resolution, consistent with the three-dimensional chromatin organization measured by in situ Hi-C in T cells. Fifteen percent of genetic variants located within ATAC-peaks affected the accessibility of the corresponding peak (local-ATAC-QTLs). Local-ATAC-QTLs have the largest effects on co-accessible peaks, are associated with gene expression and are enriched for autoimmune disease variants. Our results provide insights into how natural genetic variants modulate cis-regulatory elements, in isolation or in concert, to influence gene expression
Feasibility of trial procedures for a randomised controlled trial of a community based group exercise intervention for falls prevention for visually impaired older people: the VIOLET study
Background Visually impaired older people (VIOP) have a higher risk of falling than their sighted peers, and are likely to avoid physical activity. The aim was to adapt the existing Falls Management Exercise (FaME) programme for VIOP, delivered in the community, and to investigate the feasibility of conducting a definitive randomised controlled trial (RCT) of this adapted intervention. Methods Two-centre randomised mixed methods pilot trial and economic evaluation of the adapted group-based FaME programme for VIOP versus usual care. A one hour exercise programme ran weekly over 12 weeks at the study sites (Newcastle and Glasgow), delivered by third sector (voluntary and community) organisations. Participants were advised to exercise at home for an additional two hours over the week. Those randomised to the usual activities group received no intervention. Outcome measures were completed at baseline, 12 and 24 weeks. The potential primary outcome was the Short Form Falls Efficacy Scale – International (SFES-I). Participants’ adherence was assessed by reviewing attendance records and self-reported compliance to the home exercises. Adherence with the course content (fidelity) by instructors was assessed by a researcher. Adverse events were collected in a weekly phone call. Results Eighteen participants, drawn from community-living VIOP were screened; 68 met the inclusion criteria; 64 participants were randomised with 33 allocated to the intervention and 31 to the usual activities arm. 94% of participants provided data at the 12 week visit and 92% at 24 weeks. Adherence was high. The intervention was found to be safe with 76% attending nine or more classes. Median time for home exercise was 50 min per week. There was little or no evidence that fear of falling, balance and falls risk, physical activity, emotional, attitudinal or quality of life outcomes differed between trial arms at follow-up. Conclusions The intervention, FaME, was implemented successfully for VIOP and all progression criteria for a main trial were met. The lack of difference between groups on fear of falling was unsurprising given it was a pilot study but there may have been other contributory factors including suboptimal exercise dose and apparent low risk of falls in participants. These issues need addressing for a future trial
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