162 research outputs found
The inefficiency of re-weighted sampling and the curse of system size in high order path integration
Computing averages over a target probability density by statistical
re-weighting of a set of samples with a different distribution is a strategy
which is commonly adopted in fields as diverse as atomistic simulation and
finance. Here we present a very general analysis of the accuracy and efficiency
of this approach, highlighting some of its weaknesses. We then give an example
of how our results can be used, specifically to assess the feasibility of
high-order path integral methods. We demonstrate that the most promising of
these techniques -- which is based on re-weighted sampling -- is bound to fail
as the size of the system is increased, because of the exponential growth of
the statistical uncertainty in the re-weighted average
The effects of environmental context on laboratory rat social recognition
The effects of environmental context on laboratory rat social recognitio
Memory-Relevant Mushroom Body Output Synapses Are Cholinergic
Memories are stored in the fan-out fan-in neural architectures of the mammalian cerebellum and hippocampus and the insect mushroom bodies. However, whereas key plasticity occurs at glutamatergic synapses in mammals, the neurochemistry of the memory-storing mushroom body Kenyon cell output synapses is unknown. Here we demonstrate a role for acetylcholine (ACh) in Drosophila. Kenyon cells express the ACh-processing proteins ChAT and VAChT, and reducing their expression impairs learned olfactory-driven behavior. Local ACh application, or direct Kenyon cell activation, evokes activity in mushroom body output neurons (MBONs). MBON activation depends on VAChT expression in Kenyon cells and is blocked by ACh receptor antagonism. Furthermore, reducing nicotinic ACh receptor subunit expression in MBONs compromises odor-evoked activation and redirects odor-driven behavior. Lastly, peptidergic corelease enhances ACh-evoked responses in MBONs, suggesting an interaction between the fast- and slow-acting transmitters. Therefore, olfactory memories in Drosophila are likely stored as plasticity of cholinergic synapses
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Extracellular Vesicles from Fusarium graminearum Contain Protein Effectors Expressed during Infection of Corn.
Fusarium graminearum (Fgr) is a devastating filamentous fungal pathogen that causes diseases in cereals, while producing mycotoxins that are toxic for humans and animals, and render grains unusable. Low efficiency in managing Fgr poses a constant need for identifying novel control mechanisms. Evidence that fungal extracellular vesicles (EVs) from pathogenic yeast have a role in human disease led us to question whether this is also true for fungal plant pathogens. We separated EVs from Fgr and performed a proteomic analysis to determine if EVs carry proteins with potential roles in pathogenesis. We revealed that protein effectors, which are crucial for fungal virulence, were detected in EV preparations and some of them did not contain predicted secretion signals. Furthermore, a transcriptomic analysis of corn (Zea mays) plants infected by Fgr revealed that the genes of some of the effectors were highly expressed in vivo, suggesting that the Fgr EVs are a mechanism for the unconventional secretion of effectors and virulence factors. Our results expand the knowledge on fungal EVs in plant pathogenesis and cross-kingdom communication, and may contribute to the discovery of new antifungals
Early management of acute severe UC in the biologics era: development and international validation of a prognostic clinical index to predict steroid response
Objectives We aimed to determine whether changes in acute severe colitis (ASC) management have translated to improved outcomes and to develop a simple model predicting steroid non-response on admission.
Design Outcomes of 131 adult ASC admissions (117 patients) in Oxford, UK between 2015 and 2019 were compared with data from 1992 to 1993. All patients received standard treatment with intravenous corticosteroids and endoscopic disease activity scoring (Ulcerative Colitis Endoscopic Index of Severity (UCEIS)). Steroid non-response was defined as receiving medical rescue therapy or surgery. A predictive model developed in the Oxford cohort was validated in Australia and India (Gold Coast University Hospital 2015–2020, n=110; All India Institute of Medical Sciences, New Delhi 2018–2020, n=62).
Results In the 2015–2019 Oxford cohort, 15% required colectomy during admission vs 29% in 1992–1993 (p=0.033), while 71 (54%) patients received medical rescue therapy (27% ciclosporin, 27% anti-tumour necrosis factor, compared with 27% ciclosporin in 1992–1993 (p=0.0015). Admission C reactive protein (CRP) (false discovery rate, p=0.00066), albumin (0.0066) and UCEIS scores (0.015) predicted steroid non-response. A four-point model was developed involving CRP of ≥100 mg/L (one point), albumin of ≤25 g/L (one point), and UCEIS score of ≥4 (1 point) or ≥7 (2 points). Patients scoring 0, 1, 2, 3 and 4 in the validation cohorts had steroid response rates of 100, 75.0%, 54.9%, 18.2% and 0%, respectively. Scoring of ≥3 was 84% (95% CI 0.70 to 0.98) predictive of steroid failure (OR 11.9, 95% CI 10.8 to 13.0). Colectomy rates in the validation cohorts were were 8%–11%.
Conclusions Emergency colectomy rates for ASC have halved in 25 years to 8%–15% worldwide. Patients who will not respond to corticosteroids are readily identified on admission and may be prioritised for early intensification of therapy
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Effectiveness and safety of vedolizumab in inflammatory bowel disease patients aged 60 and over: an observational multicenter UK experience.
BACKGROUND: The GEMINI trials established the efficacy of vedolizumab in moderate-to-severe inflammatory bowel disease (IBD) and demonstrated a favorable safety profile, suggesting it may be advantageous in older patients at greater risk of treatment-related complications. However, there is a paucity of data exploring the outcomes of vedolizumab in this group. Our objective was to determine the clinical effectiveness and safety of vedolizumab in older IBD patients within a real-world multicenter UK cohort. METHODS: A retrospective review of electronic records across 6 UK hospitals was undertaken to evaluate the clinical effectiveness and safety outcomes of vedolizumab in IBD patients aged ≥60 at start of therapy. Rates of clinical response, remission and corticosteroid-free remission were assessed at weeks 14 and 52, using validated clinical indices, and were compared to historical controls from real-world vedolizumab-treated cohorts unstratified by age. RESULTS: Of 74 patients aged 60 years or above (median 66 years), 48 were included in our effectiveness analysis (29 ulcerative colitis, 19 Crohn's disease). Rates of clinical response, remission and corticosteroid-free remission at week 14 were 64%, 48% and 30%, respectively. By week 52, the rates of clinical response, remission, and corticosteroid-free remission were 52%, 38%, and 32%, respectively. Six (8%) patients experienced adverse effects. Effectiveness and safety outcomes were comparable to those of age-unstratified vedolizumab-treated cohorts. CONCLUSION: Our 1-year outcome data suggests that vedolizumab is safe and effective in older IBD patients and broadly comparable to cohorts unselected by age
Mucosal-associated invariant T (MAIT) cells are activated in the gastrointestinal tissue of patients with combination ipilimumab and nivolumab therapy-related colitis in a pathology distinct from ulcerative colitis
The aim of this study was to investigate the pathogenesis of combination ipilimumab and nivolumab-associated colitis (IN-COL) by measuring gut-derived and peripheral blood mononuclear cell (GMNC; PBMC) profiles. We studied GMNC and PBMC from patients with IN-COL, IN-treated with no adverse-events (IN-NAE), ulcerative colitis (UC) and healthy volunteers using flow cytometry. In the gastrointestinal-derived cells we found high levels of activated CD8+ T cells and mucosal-associated invariant T (MAIT) cells in IN-COL, changes that were not evident in IN-NAE or UC. UC, but not IN-C, was associated with a high proportion of regulatory T cells (Treg). We sought to determine if local tissue responses could be measured in peripheral blood. Peripherally, checkpoint inhibition instigated a rise in activated memory CD4+ and CD8+ T cells, regardless of colitis. Low circulating MAIT cells at baseline was associated with IN-COL patients compared with IN-NAE in one of two cohorts. UC, but not INCOL, was associated with high levels of circulating plasmablasts. In summary, the alterations in T cell subsets measured in IN-COL-affected tissue, characterized by high levels of activated CD8+ T cells and MAIT cells and a low proportion of Treg, reflected a pathology distinct from UC. These tissue changes differed from the periphery, where T cell activation was a widespread on-treatment effect, and circulating MAIT cell count was low but not reliably predictive of colitis
Opportunities for improving animal welfare in rodent models of epilepsy and seizures
Animal models of epilepsy and seizures, mostly involving mice and rats, are used to understand the pathophysiology of the different forms of epilepsy and their comorbidities, to identify biomarkers, and to discover new antiepileptic drugs and treatments for comorbidities. Such models represent an important area for application of the 3Rs (replacement, reduction and refinement of animal use). This report provides background information and recommendations aimed at minimising pain, suffering and distress in rodent models of epilepsy and seizures in order to improve animal welfare and optimise the quality of studies in this area. The report includes practical guidance on principles of choosing a model, induction procedures, in vivo recordings, perioperative care, welfare assessment, humane endpoints, social housing, environmental enrichment, reporting of studies and data sharing. In addition, some model-specific welfare considerations are discussed, and data gaps and areas for further research are identified. The guidance is based upon a systematic review of the scientific literature, survey of the international epilepsy research community, consultation with veterinarians and animal care and welfare officers, and the expert opinion and practical experience of the members of a Working Group convened by the United Kingdom's National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs)
Patient-reported Outcomes: the ICHOM Standard Set for Inflammatory Bowel Disease in Real-life Practice Helps Quantify Deficits in Current Care
BackgroundPatient reported outcome measures (PROMs) are key to documenting outcomes that matter most to patients and are increasingly important to commissioners of healthcare seeking value. We report the first series of the ICHOM Standard Set for Inflammatory Bowel Disease (IBD).MethodsPatients treated for ulcerative colitis (UC) or Crohn's disease (CD) in our centre were offered enrolment into the web-based TrueColours-IBD programme. Through this programme, email prompts linking to validated questionnaires were sent for symptoms, quality of life, and ICHOM IBD outcomes.ResultsThe first 1,299 consecutive patients enrolled (779 UC, 520 CD) were studied with median 270 days of follow up (IQR 116-504). 671 (52%) were female, mean age 42 years (sd 16), mean BMI 26 (sd 5.3). 483 (37%) were using advanced therapies at registration. Median adherence to fortnightly quality of life reporting and quarterly outcomes was 100% [IQR48-100%] and 100% [IQR75-100%], respectively. In the previous 12 months, prednisolone use was reported by 229 (29%) patients with UC vs. 81 (16%) with CD, p3 months. 174 (13%) patients reported an IBD-related intervention and 80 (6%) reported an unplanned hospital admission. There were high rates of fatigue (50%) and mood disturbance (23%).ConclusionOutcomes reported by patients illustrate the scale of the therapeutic deficit in current care. Proof of principle is demonstrated that PROM data can be collected continuously with little burden on healthcare professionals. This may become a metric for quality improvement programmes, or to compare outcomes
Funerary practices or food delicatessen? Human remains with anthropic marks from the Western Mediterranean Mesolithic
The identification of unarticulated human remains with anthropic marks in archaeological contexts normally involves solving two issues: a general one associated with the analysis and description of the anthropic manipulation marks, and another with regard to the interpretation of their purpose. In this paper we present new evidence of anthropophagic behaviour amongst hunter-gatherer groups of the Mediterranean Mesolithic. A total of 30 human remains with anthropic manipulation marks have been found in the Mesolithic layers of Coves de Santa Maira (Castell de Castells, Alicante, Spain), dating from ca. 10.2-9 cal ky BP. We describe the different marks identified on both human and faunal remains at the site (lithic, tooth, percussion and fire marks on bone cortex). As well as describing these marks, and considering that both human and faunal remains at the site present similar depositional and taphonomic features, this paper also contextualizes them within the archaeological context and subsistence patterns described for Mesolithic groups in the region. We cannot entirely rule out the possibility that these practices may be the result of periodic food stress suffered by the human populations. These anthropophagic events at the site coincide with a cultural change at the regional Epipalaeolithic-Mesolithic transition
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