1,483 research outputs found
Structurally similar allosteric modulators of α7 nicotinic acetylcholine receptors exhibit five distinct pharmacological effects.
Activation of nicotinic acetylcholine receptors (nAChRs) is associated with the binding of agonists such as acetylcholine to an extracellular site that is located at the interface between two adjacent receptor subunits. More recently, there has been considerable interest in compounds, such as positive and negative allosteric modulators (PAMs and NAMs), that are able to modulate nAChR function by binding to distinct allosteric sites. Here we examined a series of compounds differing only in methyl substitution of a single aromatic ring. This series of compounds includes a previously described α7-selective allosteric agonist, cis-cis-4-p-tolyl-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide (4MP-TQS), together with all other possible combinations of methyl substitution at a phenyl ring (18 additional compounds). Studies conducted with this series of compounds have revealed five distinct pharmacological effects on α7 nAChRs. These five effects can be summarized as: 1) nondesensitizing activation (allosteric agonists), 2) potentiation associated with minimal effects on receptor desensitization (type I PAMs), 3) potentiation associated with reduced desensitization (type II PAMs), 4) noncompetitive antagonism (NAMs), and 5) compounds that have no effect on orthosteric agonist responses but block allosteric modulation (silent allosteric modulators (SAMs)). Several lines of experimental evidence are consistent with all of these compounds acting at a common, transmembrane allosteric site. Notably, all of these chemically similar compounds that have been classified as nondesensitizing allosteric agonists or as nondesensitizing (type II) PAMs are cis-cis-diastereoisomers, whereas all of the NAMs, SAMs, and type I PAMs are cis-trans-diastereoisomers. Our data illustrate the remarkable pharmacological diversity of allosteric modulators acting on nAChRs
Learning About Development at A-Level
Young people’s interest in development issues has been the focus of numerous
studies but there has been little research that looks at the impact of learning of
a specific educational course. This research paper looks at the impact of studying
A-level World Development on young people in England and Wales. It summarises
the outcomes of research by Bowes in 2011 and a further survey in 2012 with
students who have completed the course.
This study looks specifically at the relevance, effectiveness and impact of the
course on students. The evidence suggests that the A-level is popular and seen
as relevant to young people’s lives and views about the world. Both teachers and
students state that the themes discussed are up-to-date and accessible to study.
In terms of effectiveness of the course overall, there is evidence of understanding
of the key issues in development, although the priorities given to particular themes
varied from school and college.
Programmes and projects on learning about development have often been
promoted because there is an assumption that mere engagement with these
themes has an impact on young people’s learning in terms of changing their
behaviour and attitudes towards taking action to reduce global poverty. The
evidence from this research shows a complex picture of impact with the emphasis
appearing to be more on the social and moral aspects of development than the
political. The research indicates positive changes in perceptions of global poverty
and inequality in the world, but less so on the more social and political aspects.
There is evidence that studying the A-level has had an impact upon the students’
future learning in higher education with Geography and Development Studies
becoming more popular.
The first full World Development A-level began in 2008 so the examination is still
relatively new. The sample taken for this study and the research by Bowes covered
a relatively small number of students. However, what is clear from this research
is that an A-level of this type can play an important contribution in deepening a
young person’s learning and understanding about development and that it is a
subject that is seen as popular and relevant to their lives
Computational Controversy
Climate change, vaccination, abortion, Trump: Many topics are surrounded by
fierce controversies. The nature of such heated debates and their elements have
been studied extensively in the social science literature. More recently,
various computational approaches to controversy analysis have appeared, using
new data sources such as Wikipedia, which help us now better understand these
phenomena. However, compared to what social sciences have discovered about such
debates, the existing computational approaches mostly focus on just a few of
the many important aspects around the concept of controversies. In order to
link the two strands, we provide and evaluate here a controversy model that is
both, rooted in the findings of the social science literature and at the same
time strongly linked to computational methods. We show how this model can lead
to computational controversy analytics that have full coverage over all the
crucial aspects that make up a controversy.Comment: In Proceedings of the 9th International Conference on Social
Informatics (SocInfo) 201
The influence of allosteric modulators and transmembrane mutations on desensitisation and activation of α7 nicotinic acetylcholine receptors.
Acetylcholine activates nicotinic acetylcholine receptors (nAChRs) by binding at an extracellular orthosteric site. Previous studies have described several positive allosteric modulators (PAMs) that are selective for homomeric α7 nAChRs. These include type I PAMs, which exert little or no effect on the rate of receptor desensitisation, and type II PAMs, which cause a dramatic loss of agonist-induced desensitisation. Here we report evidence that transmembrane mutations in α7 nAChRs have diverse effects on receptor activation and desensitisation by allosteric ligands. It has been reported previously that the L247T mutation, located toward the middle of the second transmembrane domain (at the 9' position), confers reduced levels of desensitisation. In contrast, the M260L mutation, located higher up in the TM2 domain (at the 22' position), does not show any difference in desensitisation compared to wild-type receptors. We have found that in receptors containing the L247T mutation, both type I PAMs and type II PAMs are converted into non-desensitising agonists. In contrast, in receptors containing the M260L mutation, this effect is seen only with type II PAMs. These findings, indicating that the M260L mutation has a selective effect on type II PAMs, have been confirmed both with previously described PAMs and also with a series of novel α7-selective PAMs. The novel PAMs examined in this study have close chemical similarity but diverse pharmacological properties. For example, they include compounds displaying effects on receptor desensitisation that are typical of classical type I and type II PAMs but, in addition, they include compounds with intermediate properties
Home-based isometric exercise training induced reductions resting blood pressure
Purpose:
Isometric exercise training (IET) reduces resting blood pressure (BP). Most previous protocols impose exercise barriers which undermine its effectiveness as a potential physical therapy for altering BP. An inexpensive, home-based programme would promote IET as a valuable tool in the fight against hypertension. The aims of this study were: (a) to investigate whether home-based wall squat training could successfully reduce resting BP, and (b) to explore the physiological variables that might mediate a change in resting BP.
Methods:
Twenty-eight healthy normotensive males were randomly assigned to a control and a 4 week home-based IET intervention using a crossover design with a 4 week ‘washout’ period in-between. Wall squat training was completed 3x weekly over 4 weeks with 48 hours between sessions. Each session comprised 4x 2 minute bouts of wall squat exercise performed at a participant-specific knee joint angle relative to a target HR of 95% HRpeak, with 2 minutes rest between bouts. Resting heart rate, BP, cardiac output, total peripheral resistance and stroke volume were taken at baseline and post each condition.
Results:
Resting BP (systolic = -4 ± 5, diastolic = -3 ± 3 and mean arterial = -3 ± 3 mmHg), cardiac output (-0.54 ± 0.66 L∙min-1) and heart rate (-5 ± 7 beats∙min-1) were all reduced following IET, with no change in total peripheral resistance or stroke volume compared to the control.
Conclusion:
These findings suggest the wall squat provides an effective method for reducing resting BP in the home resulting primarily from a reduction in resting heart rate
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A solution to the misrepresentations of CO2-equivalent emissions of short-lived climate pollutants under ambitious mitigation
While cumulative carbon dioxide (CO2) emissions dominate anthropogenic warming over centuries, temperatures over the coming decades are also strongly affected by short-lived climate pollutants (SLCPs), complicating the estimation of cumulative emission budgets for ambitious mitigation goals. Using conventional Global Warming Potentials (GWPs) to convert SLCPs to “CO2-equivalent” emissions misrepresents their impact on global temperature. Here we show that peak warming under a range of mitigation scenarios is determined by a linear combination of cumulative CO2 emissions to the time of peak warming and non-CO2 radiative forcing immediately prior to that time. This may be understood by expressing aggregate non-CO2 forcing as cumulative
CO2 forcing-equivalent (CO2-fe) emissions. We show further that contributions to CO2-fe emissions are well approximated by a new usage of GWP, denoted GWP*, which relates cumulative CO2 emissions to date with the current rate of emission of SLCPs. GWP* accurately indicates the impact of emissions of both long-lived and short-lived pollutants on radiative forcing and temperatures over a wide range of timescales, including under ambitious mitigation when conventional GWPs fail. Measured by GWP*,implementing the Paris Agreement would reduce the expected rate of warming in 2030 by 28% relative to a No Policy scenario. Expressing mitigation efforts in terms of their impact on future cumulative emissions aggregated using GWP* would relate them directly to contributions to future warming, better informing both burden-sharing discussions and long-term policies and measures in pursuit of ambitious global temperature goals
Is heavy eccentric calf training superior to wait-and-see, sham rehabilitation, traditional physiotherapy and other exercise interventions for pain and function in mid-portion Achilles tendinopathy?
Background: Mid-portion Achilles tendinopathy (AT) is prevalent amongst athletic and non-athletic populations with pain, stiffness and impaired function typically reported. While different management options exist, loading protocols remain the best available intervention and have been shown to be effective in the management of AT. Trials investigating loading in AT have used a variety of different protocols, and recent narrative reviews suggest that no protocol is superior to another when comparing outcomes in pain and function. However, there has been no systematic review or meta-analysis completed to determine this. Furthermore, the narrative review did not consider wait-and-see or sham interventions, thus a systematic review and met-analysis which includes wait-and see or sham interventions is warranted.
Methods: A systematic review and meta-analyses will be conducted as per the PRISMA guidelines. The databases PUBMED, CINAHL (Ovid) and CINAHL (EBSCO) will be searched for articles published from inception to 31 December 2017. Our search focuses on studies examining the improvement of pain and function when completing a loading program for mid-portion AT. Only randomised/ quasi-randomised trials will be included while case reports and case series will be excluded. The primary outcome assessing pain and function will be the Victorian Institute Sports Assessment - Achilles (VISA-A). Two reviewers will screen articles, extract data and assess the risk of bias independently with a third reviewer resolving any disagreements between the two reviewers. A meta-analysis will then be performed on the data (if appropriate) to determine if the traditional heavy load calf training protocol described by Alfredson is superior to wait-and-see, sham intervention, traditional physiotherapy, and other forms of exercise rehabilitation.
Discussion: This systematic review and meta-analysis will allow us to investigate if there are difference in pain and function when comparing wait-and-see, sham interventions, traditional physiotherapy and different exercise interventions to the traditional heavy eccentric calf training protocol for mid-portion Achilles tendon pain.
Systematic review registration: PROSPERO registration number CRD42018084493
Pilot evaluation of the psychometric properties of a self-medication Risk Assessment Tool among elderly patients in a community setting
<p>Abstract</p> <p>Background</p> <p>Although community pharmacists in the United Kingdom are expected to assess elderly patients' needs for additional support in managing their medicines, there is limited data on potentially useful assessment tools. We sought to evaluate a 13-item assessment instrument among community dwelling elderly patients, 65 years and above. The instrument is composed of a cognitive risk sub-scale of 6 items and a physical risk sub-scale of 7 items.</p> <p>Findings</p> <p>The instrument was administered to elderly patients in a survey performed in a community to the west of Glasgow, Scotland. The survey recruited 37 participants, 31 from 4 community pharmacies and 6 patients whose medication management tasks were managed by the West Glasgow Community Health and Care Partnership (managed patients). Community pharmacists independently rated 29 of the 37 participants' comprehension of, and dexterity in handling their medicines. We assessed scale reliability, convergent validity and criterion validity. In sub-analyses, we assessed differences in scores between the managed patients and those recruited from the community pharmacies, and between multi-compartment compliance aid users and non-users. The instrument showed satisfactory internal consistency (Cronbach's alpha of 0.792 for 13-item scale). There was significant strong negative correlation between the cognitive risk sub-scores and community pharmacists' assessment of comprehension (ρ = -0.546, p = 0.0038); and physical risk sub-scores and community pharmacists' assessment of dexterity (ρ = -0.491, p = 0.0093). The Area Under the Receiver Operator Characteristic Curve (AUC ± SE; 95%CI) showed that the instrument had good discriminatory capacity (0.86 ± 0.07; 0.68, 0.96). The best cut-off (sensitivity, specificity) was ≥4 (65%, 100%). In the sub-analyses, managed patients had significantly higher cognitive risk sub-scores (6.5 versus 4.0, p = 0.0461) compared to non-managed patients. There was a significant difference in total risk score (4 versus 2, p = 0.0135) and cognitive risk sub-score (4 versus 1.5, p = 0.0029) between users and non-users of multi-compartment compliance aids.</p> <p>Conclusions</p> <p>This instrument shows potential for use in identifying elderly patients who may have problems managing their own medicines in the community setting. However, more robust validity and reliability assessments are needed prior to introduction of the tool into routine practice.</p
Core Site-Moiety Maps Reveal Inhibitors and Binding Mechanisms of Orthologous Proteins by Screening Compound Libraries
Members of protein families often share conserved structural subsites for interaction with chemically similar moieties despite low sequence identity. We propose a core site-moiety map of multiple proteins (called CoreSiMMap) to discover inhibitors and mechanisms by profiling subsite-moiety interactions of immense screening compounds. The consensus anchor, the subsite-moiety interactions with statistical significance, of a CoreSiMMap can be regarded as a “hot spot” that represents the conserved binding environments involved in biological functions. Here, we derive the CoreSiMMap with six consensus anchors and identify six inhibitors (IC50<8.0 µM) of shikimate kinases (SKs) of Mycobacterium tuberculosis and Helicobacter pylori from the NCI database (236,962 compounds). Studies of site-directed mutagenesis and analogues reveal that these conserved interacting residues and moieties contribute to pocket-moiety interaction spots and biological functions. These results reveal that our multi-target screening strategy and the CoreSiMMap can increase the accuracy of screening in the identification of novel inhibitors and subsite-moiety environments for elucidating the binding mechanisms of targets
Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model
Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures
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