Mechanisms underlying the resolution of HDM induced allergic airways disease

Allergic asthma is a chronic inflammatory disease of the lung and deficiencies in pro-resolving mechanisms may contribute to the persistence of inflammation. The overall aim of this project was to establish a resolution model of house dust mite (HDM) induced allergic airway disease (AAD) and identify mediators of resolution. In our model, features of disease, induced by HDM at peak disease 4 hours, airway hyper-reactivity (AHR), Th2 lymphocytes and eosinophils remained significantly elevated 7 days after last challenge, resolving to baseline by 13 days. The levels of FoxP3+ regulatory lymphocytes also follow this pattern. However, as disease waned there was an elevation in the levels of alveolar macrophages and up regulation of the homeostatic molecule CD200R up to 13 days. Exposure to a single i.n administration of HDM in the resolved airways resulted in a rapid increase in Th2 inflammation and AHR suggesting that after resolution of HDM inflammation there is altered immune homeostasis in the lung. The pro-resolving lipid Lipoxin A4 was induced in the lung by HDM exposure and remained detectable during resolution. Depletion of alveolar macrophages during the resolution phase of allergen challenge resulted in delayed clearance of Th2 lymphocytes, airway neutrophils and interstitial macrophages. Conversely, adoptive transfer of alveolar macrophages during resolution resulted in reduced numbers of lung tissue leukocytes, specifically neutrophils and interstitial macrophages. This suggests a cross talk between these macrophage subsets and a novel interaction for pulmonary homeostasis. The anti-inflammatory peptide Annexin A1 is highly expressed by alveolar macrophages and mice deficient in Annexin A1 had enhanced AHR and Th2 immunity response to HDM. Blocking the Annexin A1 receptor FPR2 enhanced AHR and lung inflammation. Conversely, therapeutic administration of an Annexin A1 mimetic improved AHR and Th2 immunity. These studies demonstrate that Annexin A1: FPR2 pathway may be important in HDM disease and that resolution of allergic airways disease is an active process resulting in altered homeostasis of the lung.Open Acces

The Prostacyclin Analogue, Treprostinil, Used in the Treatment of Pulmonary Arterial Hypertension, is a Potent Antagonist of TREK-1 and TREK-2 Potassium Channels

Pulmonary arterial hypertension (PAH) is an aggressive vascular remodeling disease that carries a high morbidity and mortality rate. Treprostinil (Remodulin) is a stable prostacyclin analogue with potent vasodilatory and anti-proliferative activity, approved by the FDA and WHO as a treatment for PAH. A limitation of this therapy is the severe subcutaneous site pain and other forms of pain experienced by some patients, which can lead to significant non-compliance. TWIK-related potassium channels (TREK-1 and TREK-2) are highly expressed in sensory neurons, where they play a role in regulating sensory neuron excitability. Downregulation, inhibition or mutation of these channels leads to enhanced pain sensitivity. Using whole-cell patch-clamp electrophysiological recordings, we show, for the first time, that treprostinil is a potent antagonist of human TREK-1 and TREK-2 channels but not of TASK-1 channels. An increase in TASK-1 channel current was observed with prolonged incubation, consistent with its therapeutic role in PAH. To investigate treprostinil-induced inhibition of TREK, site-directed mutagenesis of a number of amino acids, identified as important for the action of other regulatory compounds, was carried out. We found that a gain of function mutation of TREK-1 (Y284A) attenuated treprostinil inhibition, while a selective activator of TREK channels, BL-1249, overcame the inhibitory effect of treprostinil. Our data suggests that subcutaneous site pain experienced during treprostinil therapy may result from inhibition of TREK channels near the injection site and that pre-activation of these channels prior to treatment has the potential to alleviate this nociceptive activity

Randomised, double-blind, placebo-controlled trials of non-individualised homeopathic treatment: systematic review and meta-analysis

Background: A rigorous systematic review and meta-analysis focused on randomised controlled trials (RCTs) of non-individualised homeopathic treatment has not previously been reported. We tested the null hypothesis that the main outcome of treatment using a non-individualised (standardised) homeopathic medicine is indistinguishable from that of placebo. An additional aim was to quantify any condition-specific effects of non-individualised homeopathic treatment. Methods: Literature search strategy, data extraction and statistical analysis all followed the methods described in a pre-published protocol. A trial comprised ‘reliable evidence’ if its risk of bias was low or it was unclear in one specified domain of assessment. ‘Effect size’ was reported as standardised mean difference (SMD), with arithmetic transformation for dichotomous data carried out as required; a negative SMD indicated an effect favouring homeopathy. Results: Forty-eight different clinical conditions were represented in 75 eligible RCTs. Forty-nine trials were classed as ‘high risk of bias’ and 23 as ‘uncertain risk of bias’; the remaining three, clinically heterogeneous, trials displayed sufficiently low risk of bias to be designated reliable evidence. Fifty-four trials had extractable data: pooled SMD was –0.33 (95% confidence interval (CI) –0.44, –0.21), which was attenuated to –0.16 (95% CI –0.31, –0.02) after adjustment for publication bias. The three trials with reliable evidence yielded a non-significant pooled SMD: –0.18 (95% CI –0.46, 0.09). There was no single clinical condition for which meta-analysis included reliable evidence. Conclusions: The quality of the body of evidence is low. A meta-analysis of all extractable data leads to rejection of our null hypothesis, but analysis of a small sub-group of reliable evidence does not support that rejection. Reliable evidence is lacking in condition-specific meta-analyses, precluding relevant conclusions. Better designed and more rigorous RCTs are needed in order to develop an evidence base that can decisively provide reliable effect estimates of non-individualised homeopathic treatment

Characterization and regulation of wild‐type and mutant TASK‐1 two pore domain potassium channels indicated in pulmonary arterial hypertension

Key points The TASK-1 channel gene (KCNK3) has been identified as a possible disease-causing gene in heritable pulmonary arterial hypertension (PAH). In the present study, we show that novel mutated TASK-1 channels, seen in PAH patients, have a substantially reduced current compared to wild-type TASK-1 channels. These mutated TASK-1 channels are located at the plasma membrane to the same degree as wild-type TASK-1 channels. ONO-RS-082 and alkaline pH 8.4 both activate TASK-1 channels but do not recover current through mutant TASK-1 channels. We show that the guanylate cyclase activator, riociguat, a novel treatment for PAH, enhances current through TASK-1 channels but does not recover current through mutant TASK-1 channels. Pulmonary arterial hypertension (PAH) affects ∼15–50 people per million. KCNK3, the gene that encodes the two pore domain potassium channel TASK-1 (K2P3.1), has been identified as a possible disease-causing gene in heritable PAH. Recently, two new mutations have been identified in KCNK3 in PAH patients: G106R and L214R. The present study aimed to characterize the functional properties and regulation of wild-type (WT) and mutated TASK-1 channels and determine how these might contribute to PAH and its treatment. Currents through WT and mutated human TASK-1 channels transiently expressed in tsA201 cells were measured using whole-cell patch clamp electrophysiology. Localization of fluorescence-tagged channels was visualized using confocal microscopy and quantified with in-cell and on-cell westerns. G106R or L214R mutated channels were located at the plasma membrane to the same degree as WT channels; however, their current was markedly reduced compared to WT TASK-1 channels. Functional current through these mutated channels could not be restored using activators of WT TASK-1 channels (pH 8.4, ONO-RS-082). The guanylate cyclase activator, riociguat, enhanced current through WT TASK-1 channels; however, similar to the other activators investigated, riociguat did not have any effect on current through mutated TASK-1 channels. Thus, novel mutations in TASK-1 seen in PAH substantially alter the functional properties of these channels. Current through these channels could not be restored by activators of TASK-1 channels. Riociguat enhancement of current through TASK-1 channels could contribute to its therapeutic benefit in the treatment of PAH

The first assessment of Batrachochytrium dendrobatidis in amphibian populations in the Kanuku Mountains Protected Area of Guyana

- Batrachochytrium dendrobatidis (Bd) is a fungal pathogen threatening hundreds of amphibian species with extinction across the globe, especially in Latin America. Extensive investigations have revealed the presence of Bd in many South American countries, but there has been a lack of such research conducted in Guyana. We assessed the presence of Bd in the amphibian populations of the Kanuku Mountains Protected Area, in the south-west of the country. We swabbed two hundred and fifty anurans and processed the samples using standard Polymerase Chain Reaction analysis to identify cutaneous presence of Bd, making this the most comprehensive investigation into the existence of Bd in Guyana. All samples were negative for the presence of Bd DNA. Given the presence of Bd in countries neighbouring Guyana, and the severe declines it has caused in amphibian populations, we consider Guyana to be under severe threat. We advocate further surveillance in Guyana to fully determine the presence or absence of Bd, and we emphasise the importance of biosecurity and monitoring in mitigating a potential outbreak of this fungal pathogen

Combined PLIF-IR thermal measurements of wavy film flows undergoing forced harmonic excitation

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.A combined PLIF/IR thermography technique was developed and employed towards the measurement of unsteady and conjugate heat transfer in thin, gravity-driven falling liquid film flows (with and without flow pulsation) over an inclined heated metal foil. Simultaneous, local film thickness, film and substrate temperature, heat flux exchanged with a heated foil and heat transfer coefficient results are reported for a range of electrically applied heat input values, flow Reynolds (Re) numbers and flow pulsation frequencies. Moreover, interfacial wave velocities were calculated from cross-correlations across successive thickness profiles. Results concerning the instantaneous and local heat transfer coefficient variation and how this is correlated with the instantaneous and local film thickness variation (waves) suggest that the heat transfer coefficient experiences an enhancement in thinner films. The particular observation is most probably attributed to a number of unsteady flow phenomena within the wavy fluid films that are not captured by the steady analysis. At low flow Re number values the mean Nusselt (Nu) was around 2.5, in agreement with laminar flow theory, while at higher Re values, higher Nu were observed. Finally, lower wave amplitude intensities were associated with higher heat transfer coefficient fluctuation intensities.cf201

Learning to work together - lessons from a reflective analysis of a research project on public involvement

Abstract Background Patient and public involvement (PPI) is now an expectation of research funders, in the UK, but there is relatively little published literature on what this means in practice – nor is there much evaluative research about implementation and outputs. Policy literature endorses the need to include PPI representation at all stages of planning, performing and research dissemination, and recommends resource allocation to these roles; but details of how to make such inputs effective in practice are less common. While literature on power and participation informs the debate, there are relatively few published case studies of how this can play out through the lived experience of PPI in research; early findings highlight key issues around access to knowledge, resources, and interpersonal respect. This article describes the findings of a case study of PPI within a study about PPI in research. Methods The aim of the study was to look at how the PPI representatives’ inputs had developed over time, key challenges and changes, and lessons learned. We used realist evaluation and normalisation process theory to frame and analyse the data, which was drawn from project documentation, minutes of meetings and workshops, field notes and observations made by PPI representatives and researchers; documented feedback after meetings and activities; and the structured feedback from two formal reflective meetings. Findings Key findings included the need for named contacts who support, integrate and work with PPI contributors and researchers, to ensure partnership working is encouraged and supported to be as effective as possible. A structure for partnership working enabled this to be enacted systematically across all settings. Some individual tensions were nonetheless identified around different roles, with possible implications for clarifying expectations and deepening understandings of the different types of PPI contribution and of their importance. Even in a team with research expertise in PPI, the data showed that there were different phases and challenges to ‘normalising’ the PPI input to the project. Mutual commitment and flexibility, embedded through relationships across the team, led to inclusion and collaboration. Conclusion Work on developing relationships and teambuilding are as important for enabling partnership between PPI representatives and researchers as more practical components such as funding and information sharing. Early explicit exploration of the different roles and their contributions may assist effective participation and satisfaction