Treatment of multidrug-resistant or rifampicin-resistant tuberculosis with an all-oral 9-month regimen containing linezolid or ethionamide in South Africa: A retrospective cohort study

BACKGROUND

In 2019, the South African tuberculosis program replaced ethionamide with linezolid as a part of an all-oral 9-month regimen. We evaluated treatment outcomes for patients assigned to regimens including linezolid in 2019 and ethionamide in 2017.

METHOD

This retrospective cohort study included patients treated for multi-drug resistant/rifampicin-resistant tuberculosis throughout South Africa between 1 Jan to 31 Dec 2017 and from 1 Jan to 31 Dec 2019. The cohort treated with a 9-month regimen containing ethionamide for four months, was compared with a cohort treated with a 9-month regimen containing linezolid for two months. The regimens were otherwise identical. Inverse probability weighting of propensity scores was used to adjust for potential confounding. A log-binomial regression model was used to estimate adjusted relative risk (aRR) comparing 24-month outcomes between cohorts including treatment success, death, loss to follow up, and treatment failure. Adverse event data were available for the linezolid cohort.

FINDINGS

817 patients were included in the cohort receiving ethionamide and 4244 in the cohort receiving linezolid. No evidence for a difference was observed between linezolid and ethionamide regimens for treatment success (aRR = 0·96, 95%CI 0·91-1·01), death (aRR = 1·01, 95%CI 0·87-1·17) or treatment failure (aRR = 0·87, 95%CI 0·44-1·75). Loss to follow up was more common in the linezolid group, although estimates were imprecise (aRR = 1·22, 95%CI 0·99-1·50).

INTERPRETATION

No significant differences in treatment success and survival were observed with substitution of linezolid for ethionamide as a part of an all-oral 9-month regimen. Linezolid is an acceptable alternative to ethionamide in this shorter regimen for treatment of multi-drug resistant/rifampicin resistant tuberculosis.

The Safety and Tolerability of Linezolid in Novel Short-Course Regimens Containing Bedaquiline, Pretomanid, and Linezolid to Treat Rifampicin-Resistant Tuberculosis: An Individual Patient Data Meta-analysis

BACKGROUND

Effectiveness, safety, tolerability, and adherence are critical considerations in shifting to shorter tuberculosis (TB) regimens. Novel 6-month oral regimens that include bedaquiline (B), pretomanid (Pa), and linezolid (L), with or without a fourth drug, have been shown to be as or more effective than the established longer regimens for the treatment of multidrug-resistant/rifampicin-resistant TB (MDR/RR-TB). We aimed to evaluate the safety and tolerability of linezolid in BPaL-containing regimens for the treatment of MDR/RR-TB among recently completed clinical trials.

METHODS

A review and meta-analysis was undertaken including published and unpublished data from clinical trials, conducted between 2010 and 2021, that evaluated regimens containing BPaL for the treatment of MDR/RR-TB. Individual patient data were obtained. For each BPaL-containing regimen, we evaluated the frequency and severity of treatment-related adverse events. The risk difference of adverse events for each regimen was calculated, in comparison to patients assigned to receiving the lowest cumulative exposure of linezolid.

RESULTS

Data from 3 clinical trials investigating 8 unique BPaL-containing regimens were included, comprising a total of 591 participants. Adverse events were more frequent in groups randomized to a higher cumulative linezolid dose. Among patients who were randomized to a daily dose of 1200 mg linezolid, 68 of 195 (35%) experienced a grade 3-4 adverse event versus 89 of 396 (22%) patients receiving BPaL-containing regimens containing 600 mg linezolid.

CONCLUSIONS

Regimens containing BPaL were relatively well tolerated when they included a daily linezolid dose of 600 mg. These novel regimens promise to improve the tolerability of treatment for MDR/RR-TB.

Macrophage-enriched Sectm1a promotes efficient efferocytosis to attenuate ischemia/reperfusion-induced cardiac injury

Efficient clearance and degradation of apoptotic cardiomyocytes by macrophages (collectively termed efferocytosis) is critical for inflammation resolution and restoration of cardiac function after myocardial ischemia/reperfusion (I/R). Here, we define secreted and transmembrane protein 1a (Sectm1a), a cardiac macrophage-enriched gene, as a modulator of macrophage efferocytosis in I/R-injured hearts. Upon myocardial I/R, Sectm1a-KO mice exhibited impaired macrophage efferocytosis, leading to massive accumulation of apoptotic cardiomyocytes, cardiac inflammation, fibrosis, and consequently, exaggerated cardiac dysfunction. By contrast, therapeutic administration of recombinant SECTM1A protein significantly enhanced macrophage efferocytosis and improved cardiac function. Mechanistically, SECTM1A could elicit autocrine effects on the activation of glucocorticoid-induced TNF receptor (GITR) at the surface of macrophages, leading to the upregulation of liver X receptor α (LXRα) and its downstream efferocytosis-related genes and lysosomal enzyme genes. Our study suggests that Sectm1a-mediated activation of the Gitr/LXRα axis could be a promising approach to enhance macrophage efferocytosis for the treatment of myocardial I/R injury.

BRD9-SMAD2/3 Orchestrates Stemness and Tumorigenesis in Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. The epigenetic mechanisms regulating CSCs are currently insufficiently understood, which hampers the development of novel strategies for eliminating CSCs.

METHODS

By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodeling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFβ/Activin-SMAD2/3 signaling pathway.

RESULTS

Inhibition and genetic ablation of BRD9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumors from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs.

CONCLUSIONS

Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

Exosome-associated lysophosphatidic acid signaling contributes to cancer pain

ABSTRACT

Pain associated with bone cancer remains poorly managed, and chemotherapeutic drugs used to treat cancer usually increase pain. The discovery of dual-acting drugs that reduce cancer and produce analgesia is an optimal approach. The mechanisms underlying bone cancer pain involve interactions between cancer cells and nociceptive neurons. We demonstrated that fibrosarcoma cells express high levels of autotaxin (ATX), the enzyme synthetizing lysophosphatidic acid (LPA). Lysophosphatidic acid increased proliferation of fibrosarcoma cells in vitro. Lysophosphatidic acid is also a pain-signaling molecule, which activates LPA receptors (LPARs) located on nociceptive neurons and satellite cells in dorsal root ganglia. We therefore investigated the contribution of the ATX-LPA-LPAR signaling to pain in a mouse model of bone cancer pain in which fibrosarcoma cells are implanted into and around the calcaneus bone, resulting in tumor growth and hypersensitivity. LPA was elevated in serum of tumor-bearing mice, and blockade of ATX or LPAR reduced tumor-evoked hypersensitivity. Because cancer cell-secreted exosomes contribute to hypersensitivity and ATX is bound to exosomes, we determined the role of exosome-associated ATX-LPA-LPAR signaling in hypersensitivity produced by cancer exosomes. Intraplantar injection of cancer exosomes into naive mice produced hypersensitivity by sensitizing C-fiber nociceptors. Inhibition of ATX or blockade of LPAR attenuated cancer exosome-evoked hypersensitivity in an ATX-LPA-LPAR-dependent manner. Parallel in vitro studies revealed the involvement of ATX-LPA-LPAR signaling in direct sensitization of dorsal root ganglion neurons by cancer exosomes. Thus, our study identified a cancer exosome-mediated pathway, which may represent a therapeutic target for treating tumor growth and pain in patients with bone cancer.

Genetic mapping of the p47 L.3.2 mutation in Drosophilamelanogaster

An EMS-based forward genetic screen was conducted in an apoptotic null background to identify genetic aberrations that contribute to regulation of cell growth in Drosophila melanogaster . The current work maps the genomic location of one of the identified mutants, L.3.2 . Genetic crosses conducted through the Fly-CURE consortium determined that the gene locus for the L.3.2 mutation is p47 on chromosome 2R.

Alpha-1 antitrypsin limits neutrophil extracellular trap disruption of airway epithelial barrier function

Neutrophil extracellular traps contribute to lung injury in cystic fibrosis and asthma, but the mechanisms are poorly understood. We sought to understand the impact of human NETs on barrier function in primary human bronchial epithelial and a human airway epithelial cell line. We demonstrate that NETs disrupt airway epithelial barrier function by decreasing transepithelial electrical resistance and increasing paracellular flux, partially by NET-induced airway cell apoptosis. NETs selectively impact the expression of tight junction genes claudins 4, 8 and 11. Bronchial epithelia exposed to NETs demonstrate visible gaps in E-cadherin staining, a decrease in full-length E-cadherin protein and the appearance of cleaved E-cadherin peptides. Pretreatment of NETs with alpha-1 antitrypsin (A1AT) inhibits NET serine protease activity, limits E-cadherin cleavage, decreases bronchial cell apoptosis and preserves epithelial integrity. In conclusion, NETs disrupt human airway epithelial barrier function through bronchial cell death and degradation of E-cadherin, which are limited by exogenous A1AT.

Coronary wave energy to predict functional recovery in patients with ischemic left ventricular dysfunction

Background

Invasive coronary angiography and non-invasive viability testing are the cornerstones of diagnosing and managing ischemic left ventricular dysfunction. At present there is no single test which serves both needs but, if developed, could revolutionise investigation of this condition. Coronary wave intensity analysis (cWIA) interrogates both contractility and microvascular physiology of the subtended myocardium [1,2] and therefore has the potential to fulfil this goal.

Objectives

We hypothesized that cWIA measured during coronary angiography would predict functional recovery with a similar accuracy to late gadolinium enhanced cardiac magnetic resonance imaging (LGE-CMR).

Methods

Patients with a left ventricular ejection fraction ≤40% and extensive coronary disease were enrolled. cWIA, fractional flow reserve and microvascular resistance were assessed with a simultaneous coronary Doppler and pressure-sensing guidewire during cardiac catheterization at rest, during hyperaemia and during low-dose dobutamine stress. Viability was assessed using LGE-CMR. Regional left ventricular function was assessed at baseline and 6-month follow up after optimization of medical therapy +/− revascularization, using transthoracic echocardiography. The primary outcome was regional functional recovery.

Results

Forty participants underwent baseline physiology, LGE-CMR and thirty had echocardiography at baseline and 6 months; 21/42 territories demonstrated functional recovery. Resting backward compression wave energy was significantly greater in recovering than non-recovering territories (−5240±3772 vs. −1873±1605 W m–2 s–1, p=0.099, Figure 1), and had comparable diagnostic accuracy to CMR (area under the curve 0.812 vs. 0.757, p=0.649, Figure 2); a threshold of −2500 W mm–2 s–1 had 86% sensitivity and 76% specificity at predicting recovery. Backward expansion wave energy did not predict recovery. FFR was numerically higher in recovering territories (0.81±0.17 vs. 0.71±0.16, p=0.058), whilst hyperaemic microvascular resistance did not differentiate recovering from non-recovering territories (1.97±0.73 vs. 2.29±1.00, p=0.287). The likelihood of functional recovery was similar in revascularised and non-revascularised territories (15/29 vs. 6/13 respectively, p=0.739). Low-dose dobutamine stress increased the energy of all waves, but did not improve the accuracy of cWIA in predicting recovery. In a regression model, resting backward compression wave energy and optimization of medical therapy predicted functional recovery; fractional flow reserve and hyperemic microvascular resistance did not.

Conclusions

Backward compression wave energy has similar accuracy to LGE-CMR in the prediction of functional recovery. cWIA has the potential to revolutionise the management of ischaemic left ventricular dysfunction, in a manner analogous to the effect of fractional flow reserve on the management of stable angina.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The British Heart Foundation Clinical Research Training Fellowship

Direct oral anticoagulants compared to vitamin K antagonists for the treatment of left ventricular thrombi

Background

Left ventricular thrombus (LVT) complicates around one in six cases of acute and chronic left ventricular systolic dysfunction and is associated with an increased risk of stroke, major systemic embolism and death, believed to be ameliorated by anticoagulation. Off-label use of direct oral anticoagulants (DOACs) for LVT has steadily increased, largely based on favourable outcomes in atrial fibrillation and venous thromboembolism, but the safety and efficacy of DOACs versus vitamin K antagonists (VKA) for LVT remains uncertain.

Purpose

The main aim of our study was to compare treatment of LVT with VKA to DOAC, focusing on all-cause mortality, stroke, major systemic emboli and major bleeding.

Methods

We conducted a retrospective observational longitudinal study of patients presenting to two large quaternary centres between 2011 and 2021 with a diagnosis of LVT. Patients were eligible if they had a documented LVT and received anticoagulation with either VKA or DOAC. Baseline data, thrombus characteristics, treatment type and duration, follow up imaging and clinical events were recorded using electronic health care records. Outcome measures included thrombus resolution, stroke and systemic embolism (SSE), major bleeding and mortality.

Results

A total of 955 patients were identified, of whom 901 received treatment with either a VKA (567 pts, 62.9%) or a DOAC (334 pts, 37.1%) and were included in the analysis. Underlying aetiologies included acute myocardial infarction (AMI) (38.3%), chronic ischaemic cardiomyopathy (38.0%) and non-ischaemic cardiomyopathy (23.7%). Rivaroxaban (43.4%) was the most frequently prescribed DOAC followed by apixaban (35.9%), and the remaining on edoxaban (20.7%). AMI related LVT was more commonly treated with DOAC (53.0%) and chronic ischaemic cardiomyopathy with VKA (72.9%).

There was a lower baseline LVEF in the VKA cohort (29.5±13.2 vs 33.1±14.2, p<0.0001). Other demographic features were comparable. Median follow up was 2.5 years (IQR: 1–3.5). There were no differences in follow up duration between the two treatments (p=0.17). Greater rates of thrombus resolution were seen in the DOAC group compared to VKA (1 year: 78.4% vs 51.4%, p<0.0001), with higher rates of persistent thrombus over the follow-up period seen in the VKA group (25.1% vs 12.9%, p<0.0001). Rates of stroke and systemic embolization were similar between the groups (VKA 9.3% vs 9.6% DOAC, p=0.93). Higher rates of bleeding (BARC >3, 8.1% VKA, 3.6% DOAC, p=0.031) (Figure 1A) and mortality (VKA 18.5%, DOAC 10.2%, p=0.001) (Figure 1B) were seen in the VKA group over the follow-up period.

Conclusions

In a large multi-centre registry of LVT of mixed aetiology, anticoagulation with DOAC was associated with earlier and greater rates of thrombus resolution and consequential reduced adverse events (major bleeding and mortality) during follow up. A funding application to support a multi-centre randomised control trial is underway.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): This work was supported by the British Heart Foundation (Fellowship FS/CRTF/21/24190 to HM) and the National Institute for Health Research (Biomedical Research Centre Award to Guy's and St Thomas' NHS FT and King's College London).

The HIV-1 proviral landscape reveals that Nef contributes to HIV-1 persistence in effector memory CD4+ T cells

Despite long-term antiretroviral therapy (ART), HIV-1 persists within a reservoir of CD4+ T cells that contribute to viral rebound if treatment is interrupted. Identifying the cellular populations that contribute to the HIV-1 reservoir and understanding the mechanisms of viral persistence are necessary to achieve an effective cure. In this regard, through Full-Length Individual Proviral Sequencing, we observed that the HIV-1 proviral landscape was different and changed with time on ART across naive and memory CD4+ T cell subsets isolated from 24 participants. We found that the proportion of genetically intact HIV-1 proviruses was higher and persisted over time in effector memory CD4+ T cells when compared with naive, central, and transitional memory CD4+ T cells. Interestingly, we found that escape mutations remained stable over time within effector memory T cells during therapy. Finally, we provided evidence that Nef plays a role in the persistence of genetically intact HIV-1. These findings posit effector memory T cells as a key component of the HIV-1 reservoir and suggest Nef as an attractive therapeutic target.

832Detecting spatial clusters of human salmonellosis in Victoria

Focus of Presentation

‘Cluster Tracker’ is an automated tool for spatial cluster detection of notifiable disease data collected by the Department of Health (DH), Victoria. The tool combines R statistical software and a SaTScan cluster detection algorithm (prospective space-time permutation scan statistic) to detect notifiable disease case clusters in Victoria and is presently implemented for salmonellosis (categorised by type and/or MLVA). The objective of the tool is to conduct an initial screening of case data to improve the prioritisation of salmonellosis cases for epidemiological investigation.

Findings

The Cluster Tracker tool parameters have been validated using historical data from 2017-2018, comparing DH outbreak and cluster investigations identified by usual surveillance activities with clusters detected by the Cluster Tracker tool. Parameter selection considered cluster detection agreement and disagreement, disease-specific epidemiological characteristics, and operational requirements. The Cluster Tracker tool was able to provide closely-aligned agreement with existing DH outbreak and cluster investigations using the validated parameters.

Implications

This automated spatial cluster detection tool complements existing desktop surveillance of salmonellosis notifications to enhance public health decision making, and serves as an example of how spatial methods can improve real-time surveillance.

Key messages

Advanced spatial statistical tools have a role alongside traditional methods to make better use of limited epidemiological capacity and improve the timeliness and prioritisation of surveillance activities for notifiable diseases.

Myocardial perfusion quantification by CMR for detection of obstructive coronary artery disease in patients with previous coronary artery bypass surgery

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): British Heart Foundation

Background

Coronary artery bypass grafting (CABG) is an established treatment for patients with advanced coronary artery disease (CAD). A subsequent recurrence of symptoms can cause the need for re-assessment of the coronary circulation. The accuracy of visually assessed stress perfusion cardiovascular magnetic resonance (CMR) for the detection of obstructive CAD is reduced in patients with prior CABG. In patients with complex multi-vessel CAD, myocardial perfusion quantification by CMR is superior to visual assessment (VA) for detection of obstructive disease however patients with CABG have been absent from previous studies.

Purpose

This study sought to assess the performance of myocardial perfusion quantification by CMR against invasive coronary angiography (ICA) for detecting obstructive CAD in patients with previous CABG.

Methods

Twenty-nine patients with a history of previous CABG and subsequent clinically indicated perfusion CMR study and invasive coronary angiography were recruited. Patients underwent a dual bolus stress perfusion CMR with late gadolinium enhancement (LGE) imaging at 3 Tesla. Stress myocardial blood flow (MBF) was estimated at the coronary territory level according to the AHA 16 segment model using Fermi function-constrained deconvolution. Segments with transmural LGE were excluded from MBF analysis. Stress perfusion images were analysed visually alongside LGE images and matched perfusion-LGE defects were considered negative. On ICA, coronary territories with lumen stenosis >70% without an unobstructed bypass graft (<70% stenosis) were considered positive.

Results

86/87 coronary territories were suitable for analysis. Sixty-five territories had at least one bypass graft including 32 territories with arterial grafts. 28/86 territories (33%) had obstructive disease on angiography. Territories with obstructive CAD had significantly lower stress MBF than unobstructed territories (1.21 [IQR: 0.96–1.45] vs 1.58 [1.40–1.84] ml/g/min, p < 0.001, Figure 1). Stress MBF had good accuracy to detect coronary territories with obstructive CAD (sensitivity 71%, specificity 84%, area under the curve (AUC) 0.83, p < 0.001, Figure 2A). For visual assessment, sensitivity was 79%, specificity 78% and diagnostic accuracy 78%. When analysis was confined to only territories with bypass grafts, stress MBF had 78% sensitivity, 81% specificity and AUC of 0.85, p < 0.001 (Figure 2B).. In this subgroup, VA had a sensitivity of 78%, specificity of 76% and a 77% diagnostic accuracy.

Conclusions

In patients with previous surgical revascularisation, quantification of stress myocardial blood flow by CMR offers good diagnostic accuracy for the detection and localisation of anatomically significant stenoses. Accuracy is reduced compared with published data in patients without coronary grafts but remains comparable to expert visual assessment.

Cellular activation, differentiation and proliferation influence the dynamics of genetically-intact proviruses over time

Human immunodeficiency virus (HIV) persists in cells despite antiretroviral therapy; however, the influence of cellular mechanisms such as activation, differentiation, and proliferation upon the distribution of proviruses over time is unclear. To address this, we used full-length sequencing to examine proviruses within memory CD4⁺ T-cell subsets longitudinally in 8 participants. Over time, the odds of identifying a provirus increased in effector and decreased in transitional memory cells. In all subsets, more activated (HLA-DR–expressing) cells contained a higher frequency of intact provirus, as did more differentiated cells such as transitional and effector memory subsets. The proportion of genetically identical proviruses increased over time, indicating that cellular proliferation was maintaining the persistent reservoir; however, the number of genetically identical proviral clusters in each subset was stable. As such, key biological processes of activation, differentiation, and proliferation influence the dynamics of the HIV reservoir and must be considered during the development of any immune intervention.

Pharmacological Inhibition of MALT1 Protease Leads to a Progressive IPEX-Like Pathology

Genetic disruption or short-term pharmacological inhibition of MALT1 protease is effective in several preclinical models of autoimmunity and B cell malignancies. Despite these protective effects, the severe reduction in regulatory T cells (Tregs) and the associated IPEX-like pathology occurring upon congenital disruption of the MALT1 protease in mice has raised concerns about the long-term safety of MALT1 inhibition. Here we describe the results of a series of toxicology studies in rat and dog species using MLT-943, a novel potent and selective MALT1 protease inhibitor. While MLT-943 effectively prevented T cell-dependent B cell immune responses and reduced joint inflammation in the collagen-induced arthritis rat pharmacology model, in both preclinical species, pharmacological inhibition of MALT1 was associated with a rapid and dose-dependent reduction in Tregs and resulted in the progressive appearance of immune abnormalities and clinical signs of an IPEX-like pathology. At the 13-week time point, rats displayed severe intestinal inflammation associated with mast cell activation, high serum IgE levels, systemic T cell activation and mononuclear cell infiltration in multiple tissues. Importantly, using thymectomized rats we demonstrated that MALT1 protease inhibition affects peripheral Treg frequency independently of effects on thymic Treg output and development. Our data confirm the therapeutic potential of MALT1 protease inhibitors but highlight the safety risks and challenges to consider before potential application of such inhibitors into the clinic.

Reducing Asthma Attacks in Children using Exhaled Nitric Oxide as a biomarker to inform treatment strategy: a randomised trial (RAACENO)

Background

Childhood asthma is a common condition. Currently there is no validated objective test which can be used to guide asthma treatment in children. This study tests the hypothesis that the addition of fractional exhaled nitric oxide (F_ENO) monitoring in addition to standard care reduces the number of exacerbations (or attacks) in children with asthma.

Methods

This is a multi-centre, randomised controlled study. Children will be included of age 6–16 years who have a diagnosis of asthma, currently use inhaled corticosteroids (ICSs) and have had an exacerbation in the previous 12 months. Exclusion criteria include being unable to provide F_ENO measurement at baseline assessment, having another chronic respiratory condition and being currently treated with maintenance oral steroids. Participants will be recruited in both primary and secondary care settings and will be randomised to either receive asthma treatment guided by F_ENO plus symptoms (F_ENO group) or asthma treatment guided by symptoms only (standard care group). Within the F_ENO group, different treatment decisions will be made dependent on changes in F_ENO. Participants will attend assessments 3, 6, 9 and 12 months post randomisation. The primary outcome is asthma exacerbation requiring prescription and/or use of an oral corticosteroid over 12 months as recorded by the participant/parent or in general practitioner records. Secondary outcomes include time to first attack, number of attacks, asthma control score and quality of life. Adherence to ICS treatment is objectively measured by an electronic logging device. Participants are invited to participate in a “phenotyping” assessment where skin prick reactivity and bronchodilator response are determined and a saliva sample is collected for DNA extraction. Qualitative interviews will be held with participants and research nurses. A health economic evaluation will take place.

Discussion

This study will evaluate whether F_ENO can provide an objective index to guide and stratify asthma treatment in children.

Trial registration

ISRCTN, ISRCTN67875351. Registered on 12 April 2017. Prospectively registered.

"Moving on" through the locked ward system for women with intellectual disabilities

Background

The move to community support for all people with intellectual disabilities is an aspiration with international significance. In this article, we draw on rich accounts from women with intellectual disabilities detained under the Mental Health Act (E&W) 1983 and staff at an National Health Service secure setting in England to explore how “moving on” is defined and perceived.

Methods

The study reports on an ethnographic study using the field‐notes and the 26 semi‐structured interviews with detained women and staff on three wards.

Results

We first explore staff conceptions of moving on, which include behavioural change and utilizing coping strategies. Then, we discuss the areas of analysis that women discussed: taking back responsibility, success in arranged relationships, acceptance of regime and resistance to progression.

Conclusion

The concepts of moving on were not determined by the women but by the service. We recommend further research which explores women's own rehabilitation requirements.

Evaluation of in vitro Assays to Assess the Modulation of Dendritic Cells Functions by Therapeutic Antibodies and Aggregates

Therapeutic antibodies have the potential to induce immunogenicity leading to the development of anti-drug antibodies (ADA) that consequently may result in reduced serum drug concentrations, a loss of efficacy or potential hypersensitivity reactions. Among other factors, aggregated antibodies have been suggested to promote immunogenicity, thus enhancing ADA production. Dendritic cells (DC) are the most efficient antigen-presenting cell population and are crucial for the initiation of T cell responses and the subsequent generation of an adaptive immune response. This work focuses on the development of predictive in vitro assays that can monitor DC maturation, in order to determine whether drug products have direct DC stimulatory capabilities. To this end, four independent laboratories aligned a common protocol to differentiate human monocyte-derived DC (moDC) that were treated with either native or aggregated preparations of infliximab, natalizumab, adalimumab, or rituximab. These drug products were subjected to different forms of physical stress, heat and shear, resulting in aggregation and the formation of subvisible particles. Each partner developed and optimized assays to monitor diverse end-points of moDC maturation: measuring the upregulation of DC activation markers via flow cytometry, analyzing cytokine, and chemokine production via mRNA and protein quantification and identifying cell signaling pathways via quantification of protein phosphorylation. These study results indicated that infliximab, with the highest propensity to form aggregates when heat-stressed, induced a marked activation of moDC as measured by an increase in CD83 and CD86 surface expression, IL-1β, IL-6, IL-8, IL-12, TNFα, CCL3, and CCL4 transcript upregulation and release of respective proteins, and phosphorylation of the intracellular signaling proteins Syk, ERK1/2, and Akt. In contrast, natalizumab, which does not aggregate under these stress conditions, induced no DC activation in any assay system, whereas adalimumab or rituximab aggregates induced only slight parameter variation. Importantly, the data generated in the different assay systems by each partner site correlated and supported the use of these assays to monitor drug-intrinsic propensities to drive maturation of DC. This moDC assay is also a valuable tool as an in vitro model to assess the intracellular mechanisms that drive DC activation by aggregated therapeutic proteins.

Indications for chest X-rays in children and how to obtain and interpret them

Chest X-ray (CXR) is one of the most common radiological investigations undertaken in practice with children. CXRs are requested for a number of suspected diagnoses, including pneumonia, pneumothorax and foreign body aspiration or ingestion. They may also be requested as part of a skeletal survey or to confirm the position of central and umbilical lines, as well as nasogastric tubes. Nurses play a vital role in ensuring that X-rays are performed in a safe and timely manner, and to ensure children are supported and positioned appropriately to obtain the best quality images. It is useful for nurses working with children to understand the underlying mechanism and rationale for requesting X-rays because this helps them to communicate the relevance of the procedure to other team members. This article provides an overview of the fundamental principles of obtaining a CXR and interpreting the images.

Dielectric characterization of Plasmodium falciparum-infected red blood cells using microfluidic impedance cytometry

Although malaria is the world's most life-threatening parasitic disease, there is no clear understanding of how certain biophysical properties of infected cells change during the malaria infection cycle. In this article, we use microfluidic impedance cytometry to measure the dielectric properties of Plasmodium falciparum-infected red blood cells (i-RBCs) at specific time points during the infection cycle. Individual parasites were identified within i-RBCs using green fluorescent protein (GFP) emission. The dielectric properties of cell sub-populations were determined using the multi-shell model. Analysis showed that the membrane capacitance and cytoplasmic conductivity of i-RBCs increased along the infection time course, due to membrane alterations caused by parasite infection. The volume ratio occupied by the parasite was estimated to vary from less than 10% at earlier stages, to approximately 90% at later stages. This knowledge could be used to develop new label-free cell sorting techniques for sample pre-enrichment, improving diagnosis.

Rab35-dependent extracellular nanovesicles are required for induction of tumour supporting stroma

Communication between diseased cells and the microenvironment is a complex yet crucial element in progression of varied pathological processes. Recent studies in cancer highlight an important role for small extracellular nanovesicles secreted by cancer cells as modulators of cancer-associated stroma, leading to enhanced angiogenesis and metastatic priming. The intrinsic factors regulating extracellular nanovesicle biogenesis and secretion are therefore relevant in studies of nano-communication in the cancer milieu. We generated prostate cancer cells bearing stable knockdown of several candidate vesicle regulating factors and examined the impact on cell health, vesicle secretion and on communication with fibroblastic stromal cells. We highlight that RAB11B and RAB35 regulate phenotypically distinct nanovesicle populations, each accounting for only around 20% of the total. Depleting RAB35, but not RAB11B leaves a remaining population of vesicles whose phenotype is insufficient for driving fibroblast to myofibroblast differentiation, leading to attenuated motile behaviours in 3D in vitro models. Co-implantation of tumour cells with stromal fibroblasts in xenografts similarly showed that RAB11B knockdown had little effect on growth rates in vivo. In contrast, significant attenuation in growth, and attenuation of myofibroblasts at the tumour site was evident when using RAB35-knockdown cells. The study concludes that a RAB35 regulated nanovesicle sub-population is particularly important for communication between cancer and stromal cells, and is required for generating a tumour-supportive microenvironment.

The intervention process in the European Fans in Training (EuroFIT) trial: a mixed method protocol for evaluation

BACKGROUND

EuroFIT is a gender-sensitised, health and lifestyle program targeting physical activity, sedentary time and dietary behaviours in men. The delivery of the program in football clubs, led by the clubs' community coaches, is designed to both attract and engage men in lifestyle change through an interest in football or loyalty to the club they support. The EuroFIT program will be evaluated in a multicentre pragmatic randomised controlled trial (RCT), for which ~1000 overweight men, aged 30-65 years, will be recruited in 15 top professional football clubs in the Netherlands, Norway, Portugal and the UK. The process evaluation is designed to investigate how implementation within the RCT is achieved in the various football clubs and countries and the processes through which EuroFIT affects outcomes.

METHODS

This mixed methods evaluation is guided by the Medical Research Council (MRC) guidance for conducting process evaluations of complex interventions. Data will be collected in the intervention arm of the EuroFIT trial through: participant questionnaires (n = 500); attendance sheets and coach logs (n = 360); observations of sessions (n = 30); coach questionnaires (n = 30); usage logs from a novel device for self-monitoring physical activity and non-sedentary behaviour (SitFIT); an app-based game to promote social support for physical activity outside program sessions (MatchFIT); interviews with coaches (n = 15); football club representatives (n = 15); and focus groups with participants (n = 30). Written standard operating procedures are used to ensure quality and consistency in data collection and analysis across the participating countries. Data will be analysed thematically within datasets and overall synthesis of findings will address the processes through which the program is implemented in various countries and clubs and through which it affects outcomes, with careful attention to the context of the football club.

DISCUSSION

The process evaluation will provide a comprehensive account of what was necessary to implement the EuroFIT program in professional football clubs within a trial setting and how outcomes were affected by the program. This will allow us to re-appraise the program's conceptual base, optimise the program for post-trial implementation and roll out, and offer suggestions for the development and implementation of future initiatives to promote health and wellbeing through professional sports clubs.

TRIAL REGISTRATION

ISRCTN81935608 . Registered on 16 June 2015.

Analysis of Parasitic Protozoa at the Single-cell Level using Microfluidic Impedance Cytometry

At present, there are few technologies which enable the detection, identification and viability analysis of protozoan pathogens including Cryptosporidium and/or Giardia at the single (oo)cyst level. We report the use of Microfluidic Impedance Cytometry (MIC) to characterise the AC electrical (impedance) properties of single parasites and demonstrate rapid discrimination based on viability and species. Specifically, MIC was used to identify live and inactive C. parvum oocysts with over 90% certainty, whilst also detecting damaged and/or excysted oocysts. Furthermore, discrimination of Cryptosporidium parvum, Cryptosporidium muris and Giardia lamblia, with over 92% certainty was achieved. Enumeration and identification of (oo)cysts can be achieved in a few minutes, which offers a reduction in identification time and labour demands when compared to existing detection methods.

Role of Tumor Necrosis Factor-α and Natural Killer Cells in Uterine Artery Function and Pregnancy Outcome in the Stroke-Prone Spontaneously Hypertensive Rat

Women with chronic hypertension are at increased risk of maternal and fetal morbidity and mortality. We have previously characterized the stroke-prone spontaneously hypertensive rat (SHRSP) as a model of deficient uterine artery function and adverse pregnancy outcome compared with the control Wistar-Kyoto. The activation of the immune system plays a role in hypertension and adverse pregnancy outcome. Therefore, we investigated the role of tumor necrosis factor-α in the SHRSP phenotype in an intervention study using etanercept (0.8 mg/kg SC) at gestational days 0, 6, 12, and 18 in pregnant SHRSP compared with vehicle-treated controls (n=6). Etanercept treatment significantly lowered systolic blood pressure after gestational day 12 and increased litter size in SHRSP. At gestational day 18, etanercept improved the function of uterine arteries from pregnant SHRSP normalizing the contractile response and increasing endothelium-dependent relaxation, resulting in increased pregnancy-dependent diastolic blood flow in the uterine arteries. We identified that the source of excess tumor necrosis factor-α in the SHRSP was a pregnancy-dependent increase in peripheral and placental CD3^- CD161⁺ natural killer cells. Etanercept treatment also had effects on placental CD161⁺ cells by reducing the expression of CD161 receptor, which was associated with a decrease in cytotoxic granzyme B expression. Etanercept treatment improves maternal blood pressure, pregnancy outcome, and uterine artery function in SHRSP by antagonizing signaling from excess tumor necrosis factor-α production and the reduction of granzyme B expression in CD161⁺ natural killer cells in SHRSP.

Abstract 046: The Role of Tumor Necrosis Factor α and Natural Killer Cells in Uterine Artery Function During Pregnancy in the Stroke Prone Spontaneously Hypertensive Rat

Objective: We have previously characterised the stroke prone spontaneously hypertensive rat (SHRSP) as a model of deficient uterine artery remodelling and identified an increase in pro-inflammatory TNFα relative to the normotensive WKY strain during pregnancy.

Method: SHRSP were treated with etanercept (0.8 mg/kg) or vehicle at gestational day (GD) 0, 6, 12 and 18. Animals were sacrificed at GD18.

Results: Etanercept reduced systolic blood pressure in the SHRSP after GD12 (ΔSBP GD 10-21 SHRSP 12.0 ± 4.17 vs. ETN 25.8 ± 4.27 mmHg; p<0.05). Uterine arteries from GD18 showed that etanercept reduced uterine artery contraction (SHRSP 57.3 ± 8.75 vs. ETN 35.2 ± 2.19 kPa; p<0.01) and increased carbachol response (SHRSP 13.8 ± 3.8 vs. ETN 40.1 ± 3.25 %; p<0.05). Uteroplacental blood flow analysed using Doppler showed that etanercept reduced uterine artery resistance index in SHRSP (SHRSP 0.79 ± 0.02 vs. ETN 0.61 ± 0.02 UARI; p<0.01). Etanercept increased litter size (SHRSP 7.80 ± 0.44 vs. ETN 12.75 ± 0.94 fetuses), reduced resorption frequency (SHRSP 66.7% vs. ETN 25.0% dams with resorption) and decreased glycogen cell loss from the placenta in SHRSP. We sought to identify the source of excess TNFα in the SHRSP. Natural killer (NK) cells (CD3-CD161+) were increased in the SHRSP relative to the WKY in the maternal circulation (WKY 1.5 ± 0.4 vs. SHRSP 6.06 ± 0.28 %; p<0.01) and placenta (WKY 11.6 ± 2.39 vs. SHRSP 659.8 ± 201.2 cells/mg; p<0.01). These NK cells produced excess TNFα in the SHRSP maternal circulation (SHRSP 6.5 ± 0.4 vs. WKY 2.5 ± 0.4 %; p<0.05) and placenta (SHRSP 65.7 ± 4.2 vs. WKY 16.9 ± 1.7 %; p<0.01) relative to the WKY. In the SHRSP placenta, etanercept treatment reduced the number of cytotoxic NK cells (SHRSP 659.8 ± 201.2 vs. ETN 148.0 ± 12.62 cells/mg; p<0.01) by down-regulating CD161 expression associated with a decrease in granzyme B production (CD161+ 71.47 ± 2.1 vs. CD161 Low 14.32 ± 0.77 % granzyme B+; p<0.01).

Conclusions: Excess TNFα plays a causative role in adverse pregnancy outcome in the SHRSP. One source of this TNFα is an increase in NK cells during gestation in the SHRSP. Etanercept targets NK cells in the SHRSP placenta and down-regulates cytotoxic granzyme B production.

Effect of subthreshold slope on the sensitivity of nanoribbon sensors

In this work, we investigate how the sensitivity of a nanowire or nanoribbon sensor is influenced by the subthreshold slope of the sensing transistor. Polysilicon nanoribbon sensors are fabricated with a wide range of subthreshold slopes and the sensitivity is characterized using pH measurements. It is shown that there is a strong relationship between the sensitivity and the device subthreshold slope. The sensitivity is characterized using the current sensitivity per pH, which is shown to increase from 1.2% ph(-1) to 33.6% ph(-1) as the subthreshold slope improves from 6.2 V dec(-1) to 0.23 V dec(-1) respectively. We propose a model that relates current sensitivity per pH to the subthreshold slope of the sensing transistor. The model shows that sensitivity is determined only on the subthreshold slope of the sensing transistor and the choice of gate insulator. The model fully explains the values of current sensitivity per pH for the broad range of subthreshold slopes obtained in our fabricated nanoribbon devices. It is also able to explain values of sensitivity reported in the literature, which range from 2.5% pH(-1) to 650% pH(-1) for a variety of nanoribbon and nanowire sensors. Furthermore, it shows that aggressive device scaling is not the key to high sensitivity. For the first time, a figure-of-merit is proposed to compare the performance of nanoscale field effect transistor sensors fabricated using different materials and technologies.

Dual-gate polysilicon nanoribbon biosensors enable high sensitivity detection of proteins

We demonstrate the advantages of dual-gate polysilicon nanoribbon biosensors with a comprehensive evaluation of different measurement schemes for pH and protein sensing. In particular, we compare the detection of voltage and current changes when top- and bottom-gate bias is applied. Measurements of pH show that a large voltage shift of 491 mV pH(-1) is obtained in the subthreshold region when the top-gate is kept at a fixed potential and the bottom-gate is varied (voltage sweep). This is an improvement of 16 times over the 30 mV pH(-1) measured using a top-gate sweep with the bottom-gate at a fixed potential. A similar large voltage shift of 175 mV is obtained when the protein avidin is sensed using a bottom-gate sweep. This is an improvement of 20 times compared with the 8.8 mV achieved from a top-gate sweep. Current measurements using bottom-gate sweeps do not deliver the same signal amplification as when using bottom-gate sweeps to measure voltage shifts. Thus, for detecting a small signal change on protein binding, it is advantageous to employ a double-gate transistor and to measure a voltage shift using a bottom-gate sweep. For top-gate sweeps, the use of a dual-gate transistor enables the current sensitivity to be enhanced by applying a negative bias to the bottom-gate to reduce the carrier concentration in the nanoribbon. For pH measurements, the current sensitivity increases from 65% to 149% and for avidin sensing it increases from 1.4% to 2.5%.

Hydrocarbon bio-jet fuel from bioconversion of poplar biomass: techno-economic assessment

BACKGROUND

Infrastructure compatible hydrocarbon biofuel proposed to qualify as renewable transportation fuel under the U.S. Energy Independence and Security Act of 2007 and Renewable Fuel Standard (RFS2) is evaluated. The process uses a hybrid poplar feedstock, which undergoes dilute acid pretreatment and enzymatic hydrolysis. Sugars are fermented to acetic acid, which undergoes conversion to ethyl acetate, ethanol, ethylene, and finally a saturated hydrocarbon end product. An unfermentable lignin stream may be burned for steam and electricity production, or gasified to produce hydrogen. During biofuel production, hydrogen gas is required and may be obtained by various methods including lignin gasification.

RESULTS

Both technical and economic aspects of the biorefinery are analyzed, with different hydrogen sources considered including steam reforming of natural gas and gasification of lignin. Cash operating costs for jet fuel production are estimated to range from 0.67 to 0.86 USD L^-1 depending on facility capacity. Minimum fuel selling prices with a 15 % discount rate are estimated to range from 1.14 to 1.79 USD L^-1. Capacities of 76, 190, and 380 million liters of jet fuel per year are investigated. Capital investments range from 356 to 1026 million USD.

CONCLUSIONS

A unique biorefinery is explored to produce a hydrocarbon biofuel with a high yield from bone dry wood of 330 L t^-1. This yield is achieved chiefly due to the use of acetogenic bacteria that do not produce carbon dioxide as a co-product during fermentation. Capital investment is significant in the biorefinery in part because hydrogen is required to produce a fully de-oxygenated fuel. Minimum selling price to achieve reasonable returns on investment is sensitive to capital financing options because of high capital costs. Various strategies, such as producing alternative, intermediate products, are investigated with the intent to reduce risk in building the proposed facility. It appears that producing and selling these intermediates may be more profitable than converting all the biomass into aviation fuel. With variability in historical petroleum prices and environmental subsidies, a high internal rate of return would be required to attract investors.

Hydrocarbon bio-jet fuel from bioconversion of poplar biomass: life cycle assessment

BACKGROUND

Bio-jet fuels compatible with current aviation infrastructure are needed as an alternative to petroleum-based jet fuel to lower greenhouse gas emissions and reduce dependence on fossil fuels. Cradle to grave life cycle analysis is used to investigate the global warming potential and fossil fuel use of converting poplar biomass to drop-in bio-jet fuel via a novel bioconversion platform. Unique to the biorefinery designs in this research is an acetogen fermentation step. Following dilute acid pretreatment and enzymatic hydrolysis, poplar biomass is fermented to acetic acid and then distilled, hydroprocessed, and oligomerized to jet fuel. Natural gas steam reforming and lignin gasification are proposed to meet hydrogen demands at the biorefineries. Separate well to wake simulations are performed using the hydrogen production processes to obtain life cycle data. Both biorefinery designs are assessed using natural gas and hog fuel to meet excess heat demands.

RESULTS

Global warming potential of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from CO2 equivalences of 60 to 66 and 32 to 73 g MJ(-1), respectively. Fossil fuel usage of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from 0.78 to 0.84 and 0.71 to 1.0 MJ MJ(-1), respectively. Lower values for each impact category result from using hog fuel to meet excess heat/steam demands. Higher values result from using natural gas to meet the excess heat demands.

CONCLUSION

Bio-jet fuels produced from the bioconversion of poplar biomass reduce the global warming potential and fossil fuel use compared with petroleum-based jet fuel. Production of hydrogen is identified as a major source of greenhouse gas emissions and fossil fuel use in both the natural gas steam reforming and lignin gasification bio-jet simulations. Using hog fuel instead of natural gas to meet heat demands can help lower the global warming potential and fossil fuel use at the biorefineries.

Abnormal uterine artery remodelling in the stroke prone spontaneously hypertensive rat

INTRODUCTION

The stroke prone spontaneously hypertensive rat (SHRSP) is an established model of human cardiovascular risk. We sought to characterise the uteroplacental vascular response to pregnancy in this model and determine whether this is affected by the pre-existing maternal hypertension.

METHODS

Doppler ultrasound and myography were utilised to assess uterine artery functional and structural changes pre-pregnancy and at gestational day 18 in SHRSP (untreated and nifedipine treated) and in the normotensive Wistar-Kyoto (WKY) rat. Maternal adaptations to pregnancy were also assessed along with histology and expression of genes involved in oxidative stress in the placenta.

RESULTS

SHRSP uterine arteries had a pulsatile blood flow and were significantly smaller (70906 ± 3903 μm(2) vs. 95656 ± 8524 μm(2) cross-sectional area; p < 0.01), had a significant increase in contractile response (57.3 ± 10.5 kPa vs 27.7 ± 1.9 kPa; p < 0.01) and exhibited impaired endothelium-dependent vasorelaxation (58.0 ± 5.9% vs 13.9 ± 4.6%; p < 0.01) compared to WKY. Despite significant blood pressure lowering, nifedipine did not improve uterine artery remodelling, function or blood flow in SHRSP. Maternal plasma sFLT-1/PlGF ratio (5.3 ± 0.3 vs 4.6 ± 0.1; p < 0.01) and the urinary albumin/creatinine ratio (1.9 ± 0.2 vs 0.6 ± 0.1; p < 0.01) was increased in SHRSP vs WKY. The SHRSP placenta had a significant reduction in glycogen cell content and an increase in Hif1α, Sod1 and Vegf.

DISCUSSION

We conclude that the SHRSP exhibits a number of promising characteristics as a model of spontaneous deficient uteroplacental remodelling that adversely affect pregnancy outcome, independent of pre-existing hypertension.

Real-time microfluidic recombinase polymerase amplification for the toxin B gene of Clostridium difficile on a SlipChip platform

Clostridium difficile is one of the key bacterial pathogens that cause infectious diarrhoea both in the developed and developing world. Isothermal nucleic acid amplification methods are increasingly used for identification of toxinogenic infection by clinical labs. For this purpose, we developed a low-cost microfluidic platform based on the SlipChip concept and implemented real-time isothermal recombinase polymerase amplification (RPA). The on-chip RPA assay targets the Clostridium difficile toxin B gene (tcdB) coding for toxin B, one of the proteins responsible for bacterial toxicity. The device was fabricated in clear acrylic using rapid prototyping methods. It has six replicate 500 nL reaction wells as well as two sets of 500 nL control wells. The reaction can be monitored in real-time using exonuclease fluorescent probes with an initial sample volume of as little as 6.4 μL. We demonstrated a limit of detection of 1000 DNA copies, corresponding to 1 fg, at a time-to-result of <20 minutes. This miniaturised platform for pathogen detection has potential for use in resource-limited environments or at the point-of-care because of its ease of use and low cost, particularly if combined with preserved reagents.