Sub-inhibitory fosmidomycin exposures elicits oxidative stress in Salmonella enterica Serovar typhimurium LT2

Fosmidomycin is a time-dependent nanomolar inhibitor of methylerythritol phosphate (MEP) synthase, which is the enzyme that catalyzes the first committed step in the MEP pathway to isoprenoids. Importantly, fosmidomycin is one of only a few MEP pathway-specific inhibitors that exhibits antimicrobial activity. Most inhibitors identified to date only exhibit activity against isolated pathway enzymes. The MEP pathway is the sole route to isoprenoids in many bacteria, yet has no human homologs. The development of inhibitors of this pathway holds promise as novel antimicrobial agents. Similarly, analyses of the bacterial response toward MEP pathway inhibitors provides valuable information toward the understanding of how emergent resistance may ultimately develop to this class of antibiotics. We have examined the transcriptional response of Salmonella enterica serovar typhimurium LT2 to sub-inhibitory concentrations of fosmidomycin via cDNA microarray and RTPCR. Within the regulated genes identified by microarray were a number of genes encoding enzymes associated with the mediation of reactive oxygen species (ROS). Regulation of a panel of genes implicated in the response of cells to oxidative stress (including genes for catalases, superoxide dismutases, and alkylhydrogen peroxide reductases) was investigated and mild upregulation in some members was observed as a function of fosmidomycin exposure over time. The extent of regulation of these genes was similar to that observed for comparable exposures to kanamycin, but differed significantly from tetracycline. Furthermore, S. typhimurium exposed to sub-inhibitory concentrations of fosmidomycin displayed an increased sensitivity to exogenous H2O2 relative to either untreated controls or kanamycin-treated cells. Our results suggest that endogenous oxidative stress is one consequence of exposures to fosmidomycin, likely through the temporal depletion of intracellular isoprenoids themselves, rather than other mechanisms that have been proposed to facilitate ROS accumulation in bacteria (e.g. cell death processes or the ability of the antibiotic to redox cycle)

A demonstration of 'broken' visual space

It has long been assumed that there is a distorted mapping between real and ‘perceived’ space, based on demonstrations of systematic errors in judgements of slant, curvature, direction and separation. Here, we have applied a direct test to the notion of a coherent visual space. In an immersive virtual environment, participants judged the relative distance of two squares displayed in separate intervals. On some trials, the virtual scene expanded by a factor of four between intervals although, in line with recent results, participants did not report any noticeable change in the scene. We found that there was no consistent depth ordering of objects that can explain the distance matches participants made in this environment (e.g. A > B > D yet also A < C < D) and hence no single one-to-one mapping between participants’ perceived space and any real 3D environment. Instead, factors that affect pairwise comparisons of distances dictate participants’ performance. These data contradict, more directly than previous experiments, the idea that the visual system builds and uses a coherent 3D internal representation of a scene

Chemotaxis: a feedback-based computational model robustly predicts multiple aspects of real cell behaviour

The mechanism of eukaryotic chemotaxis remains unclear despite intensive study. The most frequently described mechanism acts through attractants causing actin polymerization, in turn leading to pseudopod formation and cell movement. We recently proposed an alternative mechanism, supported by several lines of data, in which pseudopods are made by a self-generated cycle. If chemoattractants are present, they modulate the cycle rather than directly causing actin polymerization. The aim of this work is to test the explanatory and predictive powers of such pseudopod-based models to predict the complex behaviour of cells in chemotaxis. We have now tested the effectiveness of this mechanism using a computational model of cell movement and chemotaxis based on pseudopod autocatalysis. The model reproduces a surprisingly wide range of existing data about cell movement and chemotaxis. It simulates cell polarization and persistence without stimuli and selection of accurate pseudopods when chemoattractant gradients are present. It predicts both bias of pseudopod position in low chemoattractant gradients and-unexpectedly-lateral pseudopod initiation in high gradients. To test the predictive ability of the model, we looked for untested and novel predictions. One prediction from the model is that the angle between successive pseudopods at the front of the cell will increase in proportion to the difference between the cell's direction and the direction of the gradient. We measured the angles between pseudopods in chemotaxing Dictyostelium cells under different conditions and found the results agreed with the model extremely well. Our model and data together suggest that in rapidly moving cells like Dictyostelium and neutrophils an intrinsic pseudopod cycle lies at the heart of cell motility. This implies that the mechanism behind chemotaxis relies on modification of intrinsic pseudopod behaviour, more than generation of new pseudopods or actin polymerization by chemoattractant

Integrating case-finding and initial management for osteoarthritis, anxiety, and depression into primary care long-term condition reviews: results from the ENHANCE pilot trial.

Background: Multimorbidity is increasingly the norm; however, primary care remains focused on single diseases. Osteoarthritis, anxiety, and depression are frequently comorbid with other long-term conditions (LTCs), but rarely prioritized by clinicians.Objectives: To test the feasibility of a randomized controlled trial (RCT) of an intervention integrating case-finding and management for osteoarthritis, anxiety, and depression within LTC reviews.Methods: A pilot stepped-wedge RCT across 4 general practices recruited patients aged >= A5 years attending routine LTC reviews. General practice nurses provided usual LTC reviews (control period), then, following training, delivered the ENHANCE LTC review (intervention period). Questionnaires, an ENHANCE EMIS-embedded template and consultation audio-recordings, were used in the evaluation.Results: General practice recruitment and training attendance reached prespecified success criteria. Three hundred and eighteen of 466 (68%) of patients invited responded; however, more patients were recruited during the control period (206 control, 112 intervention). Eighty-two percent and 78% returned their 6-week and 6-month questionnaires, respectively. Integration of the ENHANCE LTC review into routine LTC reviews varied. Case-finding questions were generally used as intended for joint pain, but to a lesser extent for anxiety and depression. Initial management through referrals and signposting were lacking, and advice was more frequently provided for joint pain. The stepped-wedge design meant timing of the training was challenging and yielded differential recruitment.Conclusion: This pilot trial suggests that it is feasible to deliver a fully powered trial in primary care. Areas to optimize include improving the training and reconsidering the stepped-wedge design and the approach to recruitment by targeting those with greatest need

Improving the care of people with long-term conditions in primary care: protocol for the ENHANCE pilot trial

Background:Long-term conditions (LTCs) are important determinants of quality of life and healthcare expenditure worldwide. Whilst multimorbidity is increasingly the norm in primary care, clinical guidelines and the delivery of care remain focused on single diseases, resulting in poorer clinical outcomes. Osteoarthritis, and anxiety and/or depression frequently co-occur with other LTCs, yet are seldom prioritized by the patient or clinician, resulting in higher levels of disability, poorer prognosis, and increased healthcare costs.Objective: To examine the feasibility and acceptability of an integrated approach to LTC management, tackling the underdiagnosis and under-management of osteoarthritis-related pain and anxiety and/or depression in older adults with other LTCs in primary care.Design: The ENHANCE study is a pilot stepped-wedge cluster randomized controlled trial to test the feasibility and acceptability of a nurse-led ENHANCE LTC review consultation for identifying, assessing, and managing joint pain, and anxiety and/or depression in patients attending LTCreviews. Specific objectives (process evaluation and research outcomes) will be achieved through a theoretically informed mixed-methods approach using participant self-reported questionnaires, a medical record review, an ENHANCE EMIS template, qualitative interviews, and audio recordings of the ENHANCE LTC review.Discussion: Success of the pilot trial will be measured against the level of the primary care team engagement, assessment of training delivery, and degree of patient recruitment and retention. Patient satisfaction and treatment fidelity will also be explored

A pilot study of a nurse-led integrated care review (the INCLUDE review) for people with inflammatory rheumatological conditions in primary care: feasibility study findings.

BACKGROUND: People with inflammatory rheumatological conditions such as rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, polymyalgia rheumatica and giant cell arteritis are at an increased risk of common comorbidities including cardiovascular disease, osteoporosis and mood problems, leading to increased morbidity and mortality. Identifying and treating these problems could lead to improved patient quality of life and outcomes. Despite these risks being well-established, patients currently are not systematically targeted for management interventions for these morbidities. This study aimed to assess the feasibility of conducting a randomised controlled trial (RCT) of a nurse-led integrated care review in primary care to identify and manage these morbidities. METHODS: A pilot cluster RCT was delivered across four UK general practices. Patients with a diagnostic Read code for one of the inflammatory rheumatological conditions of interest were recruited by post. In intervention practices (n = 2), eligible patients were invited to attend the INCLUDE review. Outcome measures included health-related quality of life (EQ-5D-5L), patient activation, self-efficacy and treatment burden. A sample (n = 24) of INCLUDE review consultations were audio-recorded and assessed against a fidelity checklist. RESULTS: 453/789 (57%) patients responded to the invitation, although 114/453 (25%) were excluded as they either did not fulfil eligibility criteria or failed to provide full written consent. In the intervention practices, uptake of the INCLUDE review was high at 72%. Retention at 3 and 6?months both reached pre-specified success criteria. Participants in intervention practices had more primary care contacts than controls (mean 29 vs 22) over the 12?months, with higher prescribing of all relevant medication classes in participants in intervention practices, particularly so for osteoporosis medication (baseline 29% vs 12?month 46%). The intervention was delivered with fidelity, although potential areas for improvement were identified. CONCLUSIONS: The findings of this pilot study suggest it is feasible to deliver an RCT of the nurse-led integrated care (INCLUDE) review in primary care. A significant morbidity burden was identified. Early results suggest the INCLUDE review was associated with changes in practice. Lessons have been learnt around Read codes for patient identification and refining the nurse training. TRIAL REGISTRATION: ISRCTN, ISRCTN12765345

Revisiting the Effect of Acute P. falciparum Malaria on Epstein-Barr Virus: Host Balance in the Setting of Reduced Malaria Endemicity

Burkitt's lymphoma (BL), an EBV-associated tumour, occurs at high incidence in populations where malaria is holoendemic. Previous studies in one such population suggested that acute P.falciparum infection impairs EBV-specific T-cell surveillance, allowing expansion of EBV infected B-cells from which BL derives. We re-examined the situation in the same area, The Gambia, after a reduction in malaria endemicity. Cellular immune responses to EBV were measured in children with uncomplicated malaria before (day 0) and after treatment (day 28), comparing EBV genome loads in blood and EBV-specific CD8+ T-cell numbers (assayed by MHC Class I tetramers and IFNγ ELISPOTS) with those seen in age- and sex-matched healthy controls. No significant changes were seen in EBV genome loads, percentage of EBV-specific CD8+ T-cells and IFNγ producing T-cells in acute versus convalescent samples, nor any difference versus controls. Regression assays performed also no longer detected any impairment of EBV-specific T-cell surveillance. Acute uncomplicated malaria infection no longer alters EBV-specific immune responses in children in The Gambia. Given the recent decline in malaria incidence in that country, we hypothesise that gross disturbance of the EBV-host balance may be a specific effect of acute malaria only in children with a history of chronic/recurrent malaria challenge

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

SBML Level 3: an extensible format for the exchange and reuse of biological models

Abstract Systems biology has experienced dramatic growth in the number, size, and complexity of computational models. To reproduce simulation results and reuse models, researchers must exchange unambiguous model descriptions. We review the latest edition of the Systems Biology Markup Language (SBML), a format designed for this purpose. A community of modelers and software authors developed SBML Level 3 over the past decade. Its modular form consists of a core suited to representing reaction‐based models and packages that extend the core with features suited to other model types including constraint‐based models, reaction‐diffusion models, logical network models, and rule‐based models. The format leverages two decades of SBML and a rich software ecosystem that transformed how systems biologists build and interact with models. More recently, the rise of multiscale models of whole cells and organs, and new data sources such as single‐cell measurements and live imaging, has precipitated new ways of integrating data with models. We provide our perspectives on the challenges presented by these developments and how SBML Level 3 provides the foundation needed to support this evolution