Tadalafil in patients with chronic obstructive pulmonary disease:a randomised, double-blind, parallel-group, placebo-controlled trial

SummaryBackgroundPhosphodiesterase-5 (PDE5) inhibitors improve exercise capacity and quality of life in patients with idiopathic pulmonary arterial hypertension. However, whether such beneficial effects take place in selected populations with chronic obstructive pulmonary disease (COPD) remains uncertain. We aimed to assess the effects of tadalafil—a PDE5 inhibitor—on exercise capacity and quality of life in patients with COPD and mild pulmonary hypertension.MethodsWe did a randomised, double-blind, parallel-group, placebo-controlled trial at three centres in Scotland, UK, between Sept 1, 2010, and Sept 1, 2012. Patients with moderate to severe COPD were randomly assigned (1:1), via centralised randomisation with a computer-generated sequence and block sizes of four, to receive daily tadalafil 10 mg or placebo for 12 weeks. Patients, study investigators, outcome assessors, and those administering drugs were masked to group allocation. The primary endpoint was the mean placebo-corrected difference between the baseline and final 6 min walk distance after 12 weeks. We measured change in quality of life at baseline, 8 weeks, and 12 weeks, with standardised questionnaires. Analysis was per protocol and by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01197469.Findings120 patients were randomly assigned to receive tadalafil (n=60) or placebo (n=60), of whom 56 (93%) versus 57 (95%) completed the study. At 12 weeks the difference in 6 min walking distance between the tadalafil and placebo groups was 0·5 m (95% CI −11·6 to 12·5; p=0·937). We recorded no statistically significant changes in quality of life (between-group difference on the St George's Respiratory Questionnaire −2·64 [95% CI −6·43 to 1·15]; Research and Development version 1 short-form-36 4·08 [–1·35 to 9·52]; Minnesota Living with Heart Failure questionnaire −2·31 [–7·06 to 2·45]). 19 (32%) of 60 patients in the treatment group had dyspepsia; the severity of dyspepsia ranged from mild to severe, with four (21%) of 19 patients needing a proton-pump inhibitor. Five (8%) of 60 participants had dyspepsia in the placebo group. Headache was noted in 17 (28%) patients in the treatment group versus 5 (8%) in the placebo group, but was mild in all patients. Two (3%) patients in the treatment group had facial flushing, which resulted in one withdrawal. Other withdrawals within the tadalafil group happened after a transient ischaemic attack and two deaths (ruptured abdominal aortic aneurysm and pneumonia).InterpretationTadalafil does not improve exercise capacity or quality of life despite exerting pulmonary vasodilation.FundingChief Scientist Office for Scotland

Phenotypic change and induction of cytokeratin expression during in vitro culture of corneal stromal cells

Purpose: Cells of the corneal epithelium and stroma can be distinguished in vivo by different intermediate filaments, cytokeratins for corneal epithelial cells (CEC) and vimentin for keratocytes. Isolated and cultured keratocytes change phenotype, losing expression of keratocyte markers and gaining markers associated with mesenchymal stromal cells (MSC). This study investigates this change in phenotype in relation to intermediate filament expression in cultured corneal stromal cells (CSC) compared to CEC. Methods: Expression of epithelial markers (CK3, CK12, CK19, pan cytokeratin, E-cadherin), keratocyte markers (CD34, vimentin) and MSC markers (CD73, CD90 and CD105) were compared in CEC and CSC by immunocytochemistry and RT-qPCR. Expression was evaluated at different stages of CSC culture and compared to another stromal cell type, extracted from Wharton’s jelly (WJ-MSC). Results: In vivo keratocytes did not express cytokeratins. However, cultured CSC expressed epithelial-associated CK3, CK12 and CK19 but other cytokeratins. Expression of cytokeratins increased as CSC were passaged and decreased as CSC were induced to become quiescent. Comparatively, WJ-MSC, expressed lower levels of CK3, CK12 and CK19, but also stained for pan cytokeratin and expressed KRT5. Conclusions: Cultured CSC undergo phenotypic change during culture, expressing specific cytokeratin filaments normally associated with CEC. Cytokeratin expression begins as cells are cultured on plastic and increases with passage. This discovery may influence the way that differences are discerned between cultured CEC and CSC. Investigators need to be aware that the expression of cytokeratins does not necessarily represent epithelial contamination, and that CEC and CSC may be more related than previously recognised

Automated classification of three-dimensional reconstructions of coral reefs using convolutional neural networks

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hopkinson, B. M., King, A. C., Owen, D. P., Johnson-Roberson, M., Long, M. H., & Bhandarkar, S. M. Automated classification of three-dimensional reconstructions of coral reefs using convolutional neural networks. PLoS One, 15(3), (2020): e0230671, doi: 10.1371/journal.pone.0230671.Coral reefs are biologically diverse and structurally complex ecosystems, which have been severally affected by human actions. Consequently, there is a need for rapid ecological assessment of coral reefs, but current approaches require time consuming manual analysis, either during a dive survey or on images collected during a survey. Reef structural complexity is essential for ecological function but is challenging to measure and often relegated to simple metrics such as rugosity. Recent advances in computer vision and machine learning offer the potential to alleviate some of these limitations. We developed an approach to automatically classify 3D reconstructions of reef sections and assessed the accuracy of this approach. 3D reconstructions of reef sections were generated using commercial Structure-from-Motion software with images extracted from video surveys. To generate a 3D classified map, locations on the 3D reconstruction were mapped back into the original images to extract multiple views of the location. Several approaches were tested to merge information from multiple views of a point into a single classification, all of which used convolutional neural networks to classify or extract features from the images, but differ in the strategy employed for merging information. Approaches to merging information entailed voting, probability averaging, and a learned neural-network layer. All approaches performed similarly achieving overall classification accuracies of ~96% and >90% accuracy on most classes. With this high classification accuracy, these approaches are suitable for many ecological applications.This study was funded by grants from the Alfred P. Sloan Foundation (BMH, BR2014-049; https://sloan.org), and the National Science Foundation (MHL, OCE-1657727; https://www.nsf.gov). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript

An overview of current techniques for ocular toxicity testing

Given the hazardous nature of many materials and substances, ocular toxicity testing is required to evaluate the dangers associated with these substances after their exposure to the eye. Historically, animal tests such as the Draize test were exclusively used to determine the level of ocular toxicity by applying a test substance to a live rabbit’s eye and evaluating the biological response. In recent years, legislation in many developed countries has been introduced to try to reduce animal testing and promote alternative techniques. These techniques include ex vivo tests on deceased animal tissue, computational models that use algorithms to apply existing data to new chemicals and in vitro assays based on two dimensional (2D) and three dimensional (3D) cell culture models. Here we provide a comprehensive overview of the latest advances in ocular toxicity testing techniques, and discuss the regulatory framework used to evaluate their suitability

The development of a novel human corneal substitute using decellularized corneas

The development of a novel human corneal substitute using decellularized cornea

Combined fluorescence lifetime and surface topographical imaging of biological tissue

In this work a combined fluorescence lifetime and surface topographical imaging system is demonstrated. Based around a 126 × 192 time resolved single photon avalanche diode (SPAD) array operating in time correlated single-photon counting (TCSPC) mode, both the fluorescence lifetime and time of flight (ToF) can be calculated on a pixel by pixel basis. Initial tests on fluorescent samples show it is able to provide 4 mm resolution in distance and 0.4 ns resolution in lifetime. This combined modality has potential biomedical applications such as surgical guidance, endoscopy and diagnostic imaging. The system is demonstrated on both ovine and human pulmonary tissue samples, where it offers excellent fluorescence lifetime contrast whilst also giving a measure of the distance to the sample surfac

Electrokinetic generation of iron-rich barriers in soils:realising the potential for nuclear site management and decommissioning

Following earlier field-scale pilot work on nuclear site materials in the late 2000s, there has recently been renewed research and industry interest in the application of electrokinetic technologies for nuclear site management and remediation in the UK. One relatively novel application of electrokinetics is the use of sacrificial steel electrodes (coupled with an in situ generated pH-Eh gradient in the treated material) to precipitate sub-surface iron-rich barriers for groundwater and/or leachate containment, which could be used to grout or contain contaminated fluids in the sub-surface on working nuclear sites or sites undergoing decommissioning. Here, we report previously unpublished data from two work programmes exploring the higher Technology Readiness Level (TRL) application of this electrokinetic iron-barrier approach to materials typical of those found in the subsurface of the Sellafield nuclear licensed site, UK. The first programme, funded by the UK National Nuclear Laboratory (NNL), assessed the electrokinetic generation of iron-rich barriers at metre + scale in simulated Sellafield materials, while the second programme, funded under the current UK TRANSCEND consortium project, examined electrokinetic iron-barrier formation at smaller (&lt;1 m) scale, but in real site materials. Both programmes indicate that iron-rich barriers can be conveniently and electrokinetically grown in different geometries over reasonable timescales (months) in realistic site subsurface materials (sands), in electrolytes similar to natural waters found in the environment. Voltage requirements are low (&lt;1 V cm−1) with energy and consumables costs of no more than single-digit or tens of US dollars at the metre-plus scale. Further work is needed however to assess the longevity of the iron precipitates forming the subsurface barrier, and to explore barrier generation at the geometries and scales required for (site specific) field application.</p