501 research outputs found

    Cisplatin induced sensory neuropathy is prevented by vascular endothelial growth factor-A

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    Increased patient survival is a mark of modern anti-cancer therapy success. Unfortunately treatment side-effects such as neurotoxicity are a major long term concern. Sensory neuropathy is one of the common toxicities that can arise during platinum based chemotherapy. In many cases the current poor understanding of the neurological degeneration and lack of suitable analgesia has led to high incidences of patient drop out of treatment. VEGF-A is a prominent neuroprotective agent thus it was hypothesised to prevent cisplatin induced neuropathy. Systemic cisplatin treatment (lasting 3 weeks biweekly) resulted in mechanical allodynia and heat hyperalgesia in mice when compared to vehicle control. PGP9.5 sensory nerve fibre innervation was reduced in the plantar skin in the cisplatin treated group versus vehicle control mice. The cisplatin induced sensory neurodegeneration was associated with increased cleaved caspase 3 expression as well as a reduction in Activating Transcription Factor 3 and pan VEGF-A expression in sensory neurons. VEGF-A165b expression was unaltered between vehicle and cisplatin treatment. rhVEGF-A165a and rhVEGF-A165b both prevented cisplatin induced sensory neurodegeneration. Cisplatin exposure blunts the regenerative properties of sensory neurons thus leading to sensory neuropathy. However, here it is identified that administration of VEGF-A isoform subtypes induce regeneration and prevent cell death and are therefore a possible adjunct therapy for chemotherapy induced neuropathy

    Sensory neuronal sensitisation occurs through HMGB-1/RAGE and TRPV1 in high glucose conditions

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    Many potential causes for painful diabetic neuropathy have been proposed including actions of cytokines and growth factors. High mobility group protein B1 (HMGB1) is a RAGE agonist, increased in diabetes, that contributes to pain by modulating peripheral inflammatory responses. HMGB1 enhances nociceptive behaviour in naïve animals through an unknown mechanism. We tested the hypothesis that HMGB1 causes pain through direct neuronal activation of RAGE and alteration of nociceptive neuronal responsiveness. HMGB1 and RAGE expression were increased in skin and primary sensory (DRG) neurons of diabetic rats at times when pain behaviour was enhanced. Agonist-evoked TRPV1-mediated calcium responses increased in cultured DRG neurons from diabetic rats and in neurons from naïve rats exposed to high glucose concentrations. HMGB1-mediated increases in TRPV1-evoked calcium responses in DRG neurons were RAGE and PKC-dependent, and this was blocked by co-administration of the growth factor splice variant, VEGF-A165b. Pain behaviour and DRG RAGE expression increases were blocked by VEGF-A 165 b treatment of diabetic rats in vivo. HMGB-1-RAGE activation sensitizes DRG neurons in vitro. VEGF-A165b blocks HMGB-1/RAGE DRG activation, which may contribute to its analgesic properties in vivo

    The Hilbert Series of the One Instanton Moduli Space

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    The moduli space of k G-instantons on R^4 for a classical gauge group G is known to be given by the Higgs branch of a supersymmetric gauge theory that lives on Dp branes probing D(p + 4) branes in Type II theories. For p = 3, these (3 + 1) dimensional gauge theories have N = 2 supersymmetry and can be represented by quiver diagrams. The F and D term equations coincide with the ADHM construction. The Hilbert series of the moduli spaces of one instanton for classical gauge groups is easy to compute and turns out to take a particularly simple form which is previously unknown. This allows for a G invariant character expansion and hence easily generalisable for exceptional gauge groups, where an ADHM construction is not known. The conjectures for exceptional groups are further checked using some new techniques like sewing relations in Hilbert Series. This is applied to Argyres-Seiberg dualities.Comment: 43 pages, 22 figure

    NMN Deamidase Delays Wallerian Degeneration and Rescues Axonal Defects Caused by NMNAT2 Deficiency In Vivo

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    Axons require the axonal NAD-synthesizing enzyme NMNAT2 to survive. Injury or genetically induced depletion of NMNAT2 triggers axonal degeneration or defective axon growth. We have previously proposed that axonal NMNAT2 primarily promotes axon survival by maintaining low levels of its substrate NMN rather than generating NAD; however, this is still debated. NMN deamidase, a bacterial enzyme, shares NMN-consuming activity with NMNAT2, but not NAD-synthesizing activity, and it delays axon degeneration in primary neuronal cultures. Here we show that NMN deamidase can also delay axon degeneration in zebrafish larvae and in transgenic mice. Like overexpressed NMNATs, NMN deamidase reduces NMN accumulation in injured mouse sciatic nerves and preserves some axons for up to three weeks, even when expressed at a low level. Remarkably, NMN deamidase also rescues axonal outgrowth and perinatal lethality in a dose-dependent manner in mice lacking NMNAT2. These data further support a pro-degenerative effect of accumulating NMN in axons in vivo. The NMN deamidase mouse will be an important tool to further probe the mechanisms underlying Wallerian degeneration and its prevention.We thank Tim Self, Denise McLean, Ian Ward, and CSI/SLIM for use of imaging facilities and help with tissue processing. This work was funded by a Faculty of Medicine and Health Sciences, University of Nottingham nonclinical senior fellowship (to L.C.); a Marie Curie Intra European Fellowship (project number 301897) within the European Community 7th Framework Programme (to M.D.S. and L.C.); and an Institute Strategic Programme Grant from the Biotechnology and Biological Sciences Research Council (BBSRC) and Medical Research Council (MRC) grant MR/N004582/1 (to J.G. and M.P.C.)

    Line operators on S^1xR^3 and quantization of the Hitchin moduli space

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    We perform an exact localization calculation for the expectation values of Wilson-'t Hooft line operators in N=2 gauge theories on S^1xR^3. The expectation values are naturally expressed in terms of the complexified Fenchel-Nielsen coordinates, and form a quantum mechanically deformed algebra of functions on the associated Hitchin moduli space by Moyal multiplication. We propose that these expectation values are the Weyl transform of the Verlinde operators, which act on Liouville/Toda conformal blocks as difference operators. We demonstrate our proposal explicitly in SU(N) examples.Comment: 58 pages; v.2 minor corrections, references added; v.3 corrections corresponding to JHEP erratu

    Exact results for N = 2 supersymmetric gauge theories on compact toric manifolds and equivariant Donaldson invariants

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    We provide a contour integral formula for the exact partition function of N = 2 supersymmetric U(N) gauge theories on compact toric four-manifolds by means of supersymmetric localisation. We perform the explicit evaluation of the contour integral for U(2) N = 2 17 theory on CP2 for all instanton numbers. In the zero mass case, corresponding to the N = 4 supersymmetric gauge theory, we obtain the generating function of the Euler characteristics of instanton moduli spaces in terms of mock-modular forms. In the decoupling limit of infinite mass we find that the generating function of local and surface observables computes equivariant Donaldson invariants, thus proving in this case a longstanding conjecture by N. Nekrasov. In the case of vanishing first Chern class the resulting equivariant Donaldson polynomials are new. \ua9 2016, The Author(s)

    6-Shogaol reduced chronic inflammatory response in the knees of rats treated with complete Freund's adjuvant

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    BACKGROUND: 6-Shogaol is one of the major compounds in the ginger rhizome that may contribute to its anti-inflammatory properties. Confirmation of this contribution was sought in this study in Sprague- Dawley rats (200–250 g) treated with a single injection (0.5 ml of 1 mg/ml) of a commercial preparation of complete Freund's Adjuvant (CFA) to induce monoarthritis in the right knee over a period of 28 days. During this development of arthritis, each rat received a daily oral dose of either peanut oil (0.2 ml-control) or 6-shogaol (6.2 mg/Kg in 0.2 ml peanut oil). RESULTS: Within 2 days of CFA injection, the control group produced maximum edematous swelling of the knee that was sustained up to the end of the investigation period. But, in the 6-shogaol treated group, significantly lower magnitudes of unsustained swelling of the knees (from 5.1 ± 0.2 mm to 1.0 ± 0.2 mm, p < 0.002, n = 6) were produced during the investigation period. Unsustained swelling of the knees (from 3.2 ± 0.6 mm to 0.8 ± 1.1 mm, p < 0.00008, n = 6) was also produced after 3 days of treatment with indomethacin (2 mg/Kg/day) as a standard anti-inflammatory drug, but during the first 2 days of drug treatment swelling of the knees was significantly larger (11.6 ± 2.0 mm, p < 0.0002, n = 6) than either the controls or the 6-shogaol treated group of rats. This exaggerated effect in the early stage of indomethacin treatment was inhibited by montelukast, a cysteinyl leukotriene receptor antagonist. Also, 6-shogaol and indomethacin were most effective in reducing swelling of the knees on day 28 when the controls still had maximum swelling. The effect of 6-shogaol compared to the controls was associated with significantly lower concentration of soluble vascular cell adhesion molecule-1 (VCAM-1) in the blood and infiltration of leukocytes, including lymphocytes and monocytes/macrophages, into the synovial cavity of the knee. There was also preservation of the morphological integrity of the cartilage lining the femur compared to damage to this tissue in the peanut oil treated control group of rats. CONCLUSION: From these results, it is concluded that 6-shogaol reduced the inflammatory response and protected the femoral cartilage from damage produced in a CFA monoarthritic model of the knee joint of rats

    The pharmacological effect of BGC20-1531, a novel prostanoid EP4 receptor antagonist, in the Prostaglandin E2 human model of headache

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    Using a human Prostaglandin E2 (PGE2) model of headache, we examined whether a novel potent and selective EP4 receptor antagonist, BGC20-1531, may prevent headache and dilatation of the middle cerebral (MCA) and superficial temporal artery (STA). In a three-way cross-over trial, eight healthy volunteers were randomly allocated to receive 200 and 400 mg BGC20-1531 and placebo, followed by a 25-min infusion of PGE2. We recorded headache intensity on a verbal rating scale, MCA blood flow velocity and STA diameter. There was no difference in headache response or prevention of the dilation of the MCA or the STA (P > 0.05) with either dose of BGC20-1531 relative to placebo, although putative therapeutic exposures were not reached in all volunteers. In conclusion, these data suggest that the other EP receptors may be involved in PGE2 induced headache and dilatation in normal subjects

    Standing genetic variation and compensatory evolution in transgenic organisms: a growth-enhanced salmon simulation

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    Genetically modified strains usually are generated within defined genetic backgrounds to minimize variation for the engineered characteristic in order to facilitate basic research investigations or for commercial application. However, interactions between transgenes and genetic background have been documented in both model and commercial agricultural species, indicating that allelic variation at transgene-modifying loci are not uncommon in genomes. Engineered organisms that have the potential to allow entry of transgenes into natural populations may cause changes to ecosystems via the interaction of their specific phenotypes with ecosystem components and services. A transgene introgressing through natural populations is likely to encounter a range of natural genetic variation (among individuals or sub-populations) that could result in changes in phenotype, concomitant with effects on fitness and ecosystem consequences that differ from that seen in the progenitor transgenic strain. In the present study, using a growth hormone transgenic salmon example, we have modeled selection of modifier loci (single and multiple) in the presence of a transgene and have found that accounting for genetic background can significantly affect the persistence of transgenes in populations, potentially reducing or reversing a “Trojan gene” effect. Influences from altered life history characteristics (e.g., developmental timing, age of maturation) and compensatory demographic/ecosystem controls (e.g., density dependence) also were found to have a strong influence on transgene effects. Further, with the presence of a transgene in a population, genetic backgrounds were found to shift in non-transgenic individuals as well, an effect expected to direct phenotypes away from naturally selected optima. The present model has revealed the importance of understanding effects of selection for background genetics on the evolution of phenotypes in populations harbouring transgenes
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