169 research outputs found
The remarkable asymmetric outflow from the Cygnus Egg Nebula
We present ground based continuum images in the infrared, from 1.2 to 19µm, and an H2 2.122µm line emission image of the post-AGB star AFGL2688, the Cygnus Egg Nebula. We show that the standard model of this source, comprising a fast wind focussed by a dense, equatorial, dusty torus into a bipolar flow at position angle 15 and close to the plane of the sky, cannot explain the combination of kinematic information from previous studies and morphological information in our own observations. Nor are the images consistent with a classical bipolar flow, since the apex of the two lobes observed in scattered light in the visible and near-IR are offset in R.A. with respect to one another. We suggest a model which is physically similar, but substantially different geometrically, in which there is a bipolar flow at a position angle closer to 60, rather than 15, still collimated by a dense, equatorial, dusty torus, but the opening angle of the cones out of which the fast bipolar flow is directed is closer to 90, rather than 20 or so as previously suggested. The bipolar flow axis is inclined by about 20-30, rather than in the plane of the sky as in previous models. The dust distribution in the nebula has to be extremely clumpy, and there is evidence that large scale mass loss from the progenitor AGB star occurred in discrete phases, recurring on a timescale of 750 years. This model implies a much lower velocity for the 'fast' bipolar outflow than does the standard model, which is consistent with very recent Nobeyama Millimetre Array images in 13CO emission. In support of our new model, we present a full radiative transfer model for the source, in axial symmetry, which reveals that the final phase of heavy mass loss included a superwind phase which lasted about two hundred years and removed about 0.7 M from the envelope of the progenitor AGB star. Our results imply that the progenitor star must have been a relatively high mass AGB star. Our radiative transfer model also demonstrates convincingly that, in contrast with previous models, the core of the nebula has to be exceptionally optically thick, with an optical depth greater than unity even at 10µm
The development of accounting in UK universities:an oral history
This article reports on the development of the accounting discipline in universities in England and Scotland from the 1960s. Drawing on the oral history narratives of six distinguished accounting scholars who played a significant role in the discipline, this article documents (1) the initial influences on the teaching of accounting in English universities, (2) the different influences on the teaching of accounting in Scottish universities and (3) the influence of US universities and their scholars on the development of academic accounting in the United Kingdom. With a focus on the second wave of accounting professoriate who followed the London School of Economics (LSE) ‘Triumvirate’ of William Baxter, Harold Edey and David Solomons, this article provides first-hand insights into the shape and spread of university accounting education at a crucial stage of its development. This, in turn, develops an understanding of the contemporary academic accounting discipline in the United Kingdom.PostprintPeer reviewe
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Synbiotic approach restores intestinal homeostasis and prolongs survival in leukaemia mice with cachexia
Cancer cachexia is a multifactorial syndrome that includes muscle wasting and inflammation. As gut microbes influence host immunity and metabolism, we investigated the role of the gut microbiota in the therapeutic management of cancer and associated cachexia. A community-wide analysis of the caecal microbiome in two mouse models of cancer cachexia (acute leukaemia or subcutaneous transplantation of colon cancer cells) identified common microbial signatures, including decreased Lactobacillus spp. and increased Enterobacteriaceae and Parabacteroides goldsteinii/ASF 519. Building on this information, we administered a synbiotic containing inulin-type fructans and live Lactobacillus reuteri 100-23 to leukaemic mice. This treatment restored the Lactobacillus population and reduced the Enterobacteriaceae levels. It also reduced hepatic cancer cell proliferation, muscle wasting and morbidity, and prolonged survival. Administration of the synbiotic was associated with restoration of the expression of antimicrobial proteins controlling intestinal barrier function and gut immunity markers, but did not impact the portal metabolomics imprinting of energy demand. In summary, this study provided evidence that the development of cancer outside the gut can impact intestinal homeostasis and the gut microbial ecosystem and that a synbiotic intervention, by targeting some alterations of the gut microbiota, confers benefits to the host, prolonging survival and reducing cancer proliferation and cachexia
Differing Endoplasmic Reticulum Stress Response to Excess Lipogenesis versus Lipid Oversupply in Relation to Hepatic Steatosis and Insulin Resistance
Mitochondrial dysfunction and endoplasmic reticulum (ER) stress have been implicated in hepatic steatosis and insulin resistance. The present study investigated their roles in the development of hepatic steatosis and insulin resistance during de novo lipogenesis (DNL) compared to extrahepatic lipid oversupply. Male C57BL/6J mice were fed either a high fructose (HFru) or high fat (HFat) diet to induce DNL or lipid oversupply in/to the liver. Both HFru and HFat feeding increased hepatic triglyceride within 3 days (by 3.5 and 2.4 fold) and the steatosis remained persistent from 1 week onwards (p<0.01 vs Con). Glucose intolerance (iAUC increased by ∼60%) and blunted insulin-stimulated hepatic Akt and GSK3β phosphorylation (∼40–60%) were found in both feeding conditions (p<0.01 vs Con, assessed after 1 week). No impairment of mitochondrial function was found (oxidation capacity, expression of PGC1α, CPT1, respiratory complexes, enzymatic activity of citrate synthase & β-HAD). As expected, DNL was increased (∼60%) in HFru-fed mice and decreased (32%) in HFat-fed mice (all p<0.05). Interestingly, associated with the upregulated lipogenic enzymes (ACC, FAS and SCD1), two (PERK/eIF2α and IRE1/XBP1) of three ER stress pathways were significantly activated in HFru-fed mice. However, no significant ER stress was observed in HFat-fed mice during the development of hepatic steatosis. Our findings indicate that HFru and HFat diets can result in hepatic steatosis and insulin resistance without obvious mitochondrial defects via different lipid metabolic pathways. The fact that ER stress is apparent only with HFru feeding suggests that ER stress is involved in DNL per se rather than resulting from hepatic steatosis or insulin resistance
Osteoclast Activated FoxP3+ CD8+ T-Cells Suppress Bone Resorption in vitro
BACKGROUND: Osteoclasts are the body's sole bone resorbing cells. Cytokines produced by pro-inflammatory effector T-cells (T(EFF)) increase bone resorption by osteoclasts. Prolonged exposure to the T(EFF) produced cytokines leads to bone erosion diseases such as osteoporosis and rheumatoid arthritis. The crosstalk between T-cells and osteoclasts has been termed osteoimmunology. We have previously shown that under non-inflammatory conditions, murine osteoclasts can recruit naïve CD8 T-cells and activate these T-cells to induce CD25 and FoxP3 (Tc(REG)). The activation of CD8 T-cells by osteoclasts also induced the cytokines IL-2, IL-6, IL-10 and IFN-γ. Individually, these cytokines can activate or suppress osteoclast resorption. PRINCIPAL FINDINGS: To determine the net effect of Tc(REG) on osteoclast activity we used a number of in vitro assays. We found that Tc(REG) can potently and directly suppress bone resorption by osteoclasts. Tc(REG) could suppress osteoclast differentiation and resorption by mature osteoclasts, but did not affect their survival. Additionally, we showed that Tc(REG) suppress cytoskeletal reorganization in mature osteoclasts. Whereas induction of Tc(REG) by osteoclasts is antigen-dependent, suppression of osteoclasts by Tc(REG) does not require antigen or re-stimulation. We demonstrated that antibody blockade of IL-6, IL-10 or IFN-γ relieved suppression. The suppression did not require direct contact between the Tc(REG) and osteoclasts. SIGNIFICANCE: We have determined that osteoclast-induced Tc(REG) can suppress osteoclast activity, forming a negative feedback system. As the CD8 T-cells are activated in the absence of inflammatory signals, these observations suggest that this regulatory loop may play a role in regulating skeletal homeostasis. Our results provide the first documentation of suppression of osteoclast activity by CD8 regulatory T-cells and thus, extend the purview of osteoimmunology
The therapeutic potential of regulatory T cells for the treatment of autoimmune disease
IntroductionImmune tolerance remains the holy grail of therapeutic immunology in the fields of organ and tissue transplant rejection, autoimmune diseases, and allergy and asthma. We have learned that FoxP3(+)CD4(+) regulatory T cells play a vital role in both the induction and maintenance of self-tolerance.Areas coveredIn this opinion piece, we highlight regulatory T cells (Treg) cell biology and novel immune treatments to take advantage of these cells as potent therapeutics. We discuss the potential to utilize Treg and Treg-friendly therapies to replace current general immunosuppressives and induce tolerance as a path towards a drug-free existence without associated toxicities.Expert opinionFinally, we opine on the fact that biomedicine sits on the cusp of a new revolution: the use of human cells as versatile therapeutic engines. We highlight the challenges and opportunities associated with the development of a foundational cellular engineering science that provides a systematic framework for safely and predictably regulating cellular behaviors. Although Treg therapy has become a legitimate clinical treatment, development of the therapy will require a better understanding of the underlying Treg biology, manufacturing advances to promote cost effectiveness and combinations with other drugs to alter the pathogenicity/regulatory balance
P2RX7 Purinoceptor: A Therapeutic Target for Ameliorating the Symptoms of Duchenne Muscular Dystrophy
open access articleDuchenne muscular dystrophy (DMD) is the most common inherited muscle disease, leading to severe disability and death in young men. Death is caused by the progressive degeneration of striated muscles aggravated by sterile inflammation. The pleiotropic effects of the mutant gene also include cognitive and behavioral impairments and low bone density.
Current interventions in DMD are palliative only as no treatment improves the long-term
outcome. Therefore, approaches with a translational potential should be investigated, and
key abnormalities downstream from the absence of the DMD product, dystrophin, appear to be strong therapeutic targets. We and others have demonstrated that DMD mutations alter ATP signaling and have identified P2RX7 purinoceptor up-regulation as being responsible for the death of muscles in the mdx mouse model of DMD and human DMD lymphoblasts. Moreover, the ATP–P2RX7 axis, being a crucial activator of innate immune responses, can contribute to DMD pathology by stimulating chronic inflammation. We investigated whether ablation of P2RX7 attenuates the DMD model mouse phenotype to assess receptor suitability as a therapeutic target
Identification of microRNAs associated with allergic airway disease using a genetically diverse mouse population
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