524 research outputs found

    Bayesian estimation of prevalence of paratuberculosis in dairy herds enrolled in a voluntary Johne’s Disease Control Programme in Ireland

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    Bovine paratuberculosis is a disease characterised by chronic granulomatous enteritis which manifests clinically as a protein-losing enteropathy causing diarrhoea, hypoproteinaemia, emaciation and, eventually death. Some evidence exists to suggest a possible zoonotic link and a national voluntary Johne’s Disease Control Programme was initiated by Animal Health Ireland in 2013. The objective of this study was to estimate herd-level true prevalence (HTP) and animal-level true prevalence (ATP) of paratuberculosis in Irish herds enrolled in the national voluntary JD control programme during 2013–14. Two datasets were used in this study. The first dataset had been collected in Ireland during 2005 (5822 animals from 119 herds), and was used to construct model priors. Model priors were updated with a primary (2013–14) dataset which included test records from 99,101 animals in 1039 dairy herds and was generated as part of the national voluntary JD control programme. The posterior estimate of HTP from the final Bayesian model was 0.23–0.34 with a 95% probability. Across all herds, the median ATP was found to be 0.032 (0.009, 0.145). This study represents the first use of Bayesian methodology to estimate the prevalence of paratuberculosis in Irish dairy herds. The HTP estimate was higher than previous Irish estimates but still lower than estimates from other major dairy producing countries

    A phase I/II trial of sorafenib and infliximab in advanced renal cell carcinoma

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    There is clinical evidence to suggest that tumour necrosis factor-α (TNF-α) may be a therapeutic target in renal cell carcinoma (RCC). Multi-targeted kinase inhibitors, such as sorafenib and sunitinib, have become standard of care in advanced RCC. The anti-TNF-α monoclonal antibody infliximab and sorafenib have differing cellular mechanisms of action. We conducted a phase I/II trial to determine the safety and efficacy of infliximab in combination with sorafenib in patients with advanced RCC

    Modulation of apoptosis in human hepatocellular carcinoma (HepG2 cells) by a standardized herbal decoction of Nigella sativa seeds, Hemidesmus indicus roots and Smilax glabra rhizomes with anti- hepatocarcinogenic effects

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    <p>Abstract</p> <p>Background</p> <p>A standardized poly-herbal decoction of <it>Nigella sativa </it>seeds, <it>Hemidesmus indicus </it>roots and <it>Smilax glabra </it>rhizomes used traditionally in Sri Lanka for cancer therapy has been demonstrated previously, to have anti-hepatocarcinogenic potential. Cytotoxicity, antioxidant activity, anti-inflammatory activity, and up regulation of p53 and p21 activities are considered to be some of the possible mechanisms through which the above decoction may mediate its anti-hepatocarcinogenic action. The main aim of the present study was to determine whether apoptosis is also a major mechanism by which the decoction mediates its anti-hepatocarcinogenic action.</p> <p>Methods</p> <p>Evaluation of apoptosis in HepG2 cells was carried out by (a) microscopic observations of cell morphology, (b) DNA fragmentation analysis, (c) activities of caspase 3 and 9, as well as by (d) analysis of the expression of pro-apoptotic (Bax) and anti-apoptotic (Bcl-2) proteins associated with cell death.</p> <p>Results</p> <p>The results demonstrated that in HepG2 cells, the decoction can induce (a) DNA fragmentation and (b) characteristic morphological changes associated with apoptosis (nuclear condensation, membrane blebbing, nuclear fragmentation and apoptotic bodies). The decoction could also, in a time and dose dependent manner, up regulate the expression of the pro-apoptotic gene <it>Bax </it>and down regulate expression of anti-apoptotic <it>Bcl-2 </it>gene (as evident from RT-PCR analysis, immunohistochemistry and western blotting). Further, the decoction significantly (<it>p </it>< .001) enhanced the activities of caspase-3 and caspase-9 in a time and dose dependent manner.</p> <p>Conclusions</p> <p>Overall findings provide confirmatory evidence to demonstrate that the decoction may mediate its reported anti-hepatocarcinogenic effect, at least in part, through modulation of apoptosis.</p

    Eosinophils Are Recruited in Response to Chitin Exposure and Enhance Th2-Mediated Immune Pathology in Aspergillus fumigatus Infection

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    In patients infected with the fungus Aspergillus fumigatus, Th1 responses are considered protective, while Th2 responses are associated with increased morbidity and mortality. How host-pathogen interactions influence the development of these protective or detrimental immune responses is not clear. We compared lung immune responses to conidia from two fungal isolates that expressed different levels of the fungal cell wall component chitin. We observed that repeated aspirations of the high-chitin-expressing isolate Af5517 induced increased airway eosinophilia in the lungs of recipient mice compared to the level of eosinophilia induced by isolate Af293. CD4+ T cells in the bronchoalveolar lavage fluid (BALF) of Af5517-aspirated mice displayed decreased gamma interferon secretion and increased interleukin-4 transcription. In addition, repeated aspirations of Af5517 induced lung transcription of the Th2-associated chemokines CCL11 (eotaxin-1) and CCL22 (macrophage-derived chemokine). Eosinophil recruitment in response to conidial aspiration was correlated with the level of chitin exposure during germination and was decreased by constitutive lung chitinase expression. Moreover, eosinophil-deficient mice subjected to multiple aspirations of Af5517 prior to neutrophil depletion and infection exhibited decreased morbidity and fungal burden compared to the levels of morbidity and fungal burden found in wild-type mice. These results suggest that exposure of chitin in germinating conidia promotes eosinophil recruitment and ultimately induces Th2-skewed immune responses after repeated aspiration. Furthermore, our results suggest that eosinophils should be examined as a potential therapeutic target in patients that mount poorly protective Th2 responses to A. fumigatus infection

    Comparison of TNFα to Lipopolysaccharide as an Inflammagen to Characterize the Idiosyncratic Hepatotoxicity Potential of Drugs: Trovafloxacin as an Example

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    Idiosyncratic drug reactions (IDRs) are poorly understood, unpredictable, and not detected in preclinical studies. Although the cause of these reactions is likely multi-factorial, one hypothesis is that an underlying inflammatory state lowers the tolerance to a xenobiotic. Previously used in an inflammation IDR model, bacterial lipopolysaccharide (LPS) is heterogeneous in nature, making development of standardized testing protocols difficult. Here, the use of rat tumor necrosis factor-α (TNFα) to replace LPS as an inflammatory stimulus was investigated. Sprague-Dawley rats were treated with separate preparations of LPS or TNFα, and hepatic transcriptomic effects were compared. TNFα showed enhanced consistency at the transcriptomic level compared to LPS. TNFα and LPS regulated similar biochemical pathways, although LPS was associated with more robust inflammatory signaling than TNFα. Rats were then codosed with TNFα and trovafloxacin (TVX), an IDR-associated drug, and evaluated by liver histopathology, clinical chemistry, and gene expression analysis. TNFα/TVX induced unique gene expression changes that clustered separately from TNFα/levofloxacin, a drug not associated with IDRs. TNFα/TVX cotreatment led to autoinduction of TNFα resulting in potentiation of underlying gene expression stress signals. Comparison of TNFα/TVX and LPS/TVX gene expression profiles revealed similarities in the regulation of biochemical pathways. In conclusion, TNFα could be used in lieu of LPS as an inflammatory stimulus in this model of IDRs

    A series of Fas receptor agonist antibodies that demonstrate an inverse correlation between affinity and potency

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    Receptor agonism remains poorly understood at the molecular and mechanistic level. In this study, we identified a fully human anti-Fas antibody that could efficiently trigger apoptosis and therefore function as a potent agonist. Protein engineering and crystallography were used to mechanistically understand the agonistic activity of the antibody. The crystal structure of the complex was determined at 1.9 Å resolution and provided insights into epitope recognition and comparisons with the natural ligand FasL (Fas ligand). When we affinity-matured the agonist antibody, we observed that, surprisingly, the higher-affinity antibodies demonstrated a significant reduction, rather than an increase, in agonist activity at the Fas receptor. We propose and experimentally demonstrate a model to explain this non-intuitive impact of affinity on agonist antibody signalling and explore the implications for the discovery of therapeutic agonists in general

    A multi-targeted approach to suppress tumor-promoting inflammation

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    Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes

    Tumour necrosis factor-alpha expression in tumour islets confers a survival advantage in non-small cell lung cancer

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    <p>Abstract</p> <p>Background</p> <p>The role of TNFα in cancer is complex with both pro-tumourigenic and anti-tumourigenic roles proposed. We hypothesised that anatomical microlocalisation is critical for its function.</p> <p>Methods</p> <p>This study used immunohistochemistry to investigate the expression of TNFα in the tumour islets and stroma with respect to survival in 133 patients with surgically resected NSCLC.</p> <p>Results</p> <p>TNFα expression was increased in the tumour islets of patients with above median survival (AMS) compared to those with below median survival (BMS)(p = 0.006), but similar in the stroma of both groups. Increasing tumour islet TNFα density was a favorable independent prognostic indicator (p = 0.048) while stromal TNFα density was an independent predictor of reduced survival (p = 0.007). Patients with high TNFα expression (upper tertile) had a significantly higher 5-year survival compared to patients in the lower tertile (43% versus 22%, p = 0.01). In patients with AMS, 100% of TNFα<sup>+ </sup>cells were macrophages and mast cells, compared to only 28% in the islets and 50% in the stroma of BMS patients (p < 0.001).</p> <p>Conclusions</p> <p>The expression of TNFα in the tumour islets of patients with NSCLC is associated with improved survival suggesting a role in the host anti-tumour immunological response. The expression of TNFα by macrophages and mast cells is critical for this relationship.</p
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