68 research outputs found

    To nobody… Guibert’s Mes parents: Love Letter or Hate Mail?

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    This article compares aspects of the autofictional modes of self-representation at play in Genet’s Journal du voleur [The Thief’s Journal] and Hervé Guibert’s Mes parents [My Parents]. Despite their different historical periods of production (1949 and 1986, respectively), each text deploys key aspects of the seemingly autobiographical text (recounting the event of birth, significance of the family name, dawning sense of sexual desire and identity) in order to portray a sense of being at odds with prevailing strictures of belonging and good taste. Despite foregrounding a sense of ‘misfitting’, which is primarily located in experiences of, and related to, gay sexuality, the texts also testify to the enduring appeal and imposed potency of the socially sanctioned desire for straightforward autobiographical selfhood. Taken together, the texts suggest a reading which foregrounds shifting textual pluralities of reimagined, transitory, textual forms of selfhood rather than a named singular sel

    Development of an invasively monitored porcine model of acetaminophen-induced acute liver failure

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    Background: The development of effective therapies for acute liver failure (ALF) is limited by our knowledge of the pathophysiology of this condition, and the lack of suitable large animal models of acetaminophen toxicity. Our aim was to develop a reproducible invasively-monitored porcine model of acetaminophen-induced ALF. Method: 35kg pigs were maintained under general anaesthesia and invasively monitored. Control pigs received a saline infusion, whereas ALF pigs received acetaminophen intravenously for 12 hours to maintain blood concentrations between 200-300 mg/l. Animals surviving 28 hours were euthanased. Results: Cytochrome p450 levels in phenobarbital pre-treated animals were significantly higher than non pre-treated animals (300 vs 100 pmol/mg protein). Control pigs (n=4) survived 28-hour anaesthesia without incident. Of nine pigs that received acetaminophen, four survived 20 hours and two survived 28 hours. Injured animals developed hypotension (mean arterial pressure; 40.8+/-5.9 vs 59+/-2.0 mmHg), increased cardiac output (7.26+/-1.86 vs 3.30+/-0.40 l/min) and decreased systemic vascular resistance (8.48+/-2.75 vs 16.2+/-1.76 mPa/s/m3). Dyspnoea developed as liver injury progressed and the increased pulmonary vascular resistance (636+/-95 vs 301+/-26.9 mPa/s/m3) observed may reflect the development of respiratory distress syndrome. Liver damage was confirmed by deterioration in pH (7.23+/-0.05 vs 7.45+/-0.02) and prothrombin time (36+/-2 vs 8.9+/-0.3 seconds) compared with controls. Factor V and VII levels were reduced to 9.3 and 15.5% of starting values in injured animals. A marked increase in serum AST (471.5+/-210 vs 42+/-8.14) coincided with a marked reduction in serum albumin (11.5+/-1.71 vs 25+/-1 g/dL) in injured animals. Animals displayed evidence of renal impairment; mean creatinine levels 280.2+/-36.5 vs 131.6+/-9.33 mumol/l. Liver histology revealed evidence of severe centrilobular necrosis with coagulative necrosis. Marked renal tubular necrosis was also seen. Methaemoglobin levels did not rise >5%. Intracranial hypertension was not seen (ICP monitoring), but there was biochemical evidence of encephalopathy by the reduction of Fischer's ratio from 5.6 +/- 1.1 to 0.45 +/- 0.06. Conclusion: We have developed a reproducible large animal model of acetaminophen-induced liver failure, which allows in-depth investigation of the pathophysiological basis of this condition. Furthermore, this represents an important large animal model for testing artificial liver support systems

    The Role of CyaY in Iron Sulfur Cluster Assembly on the E. coli IscU Scaffold Protein

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    Progress in understanding the mechanism underlying the enzymatic formation of iron-sulfur clusters is difficult since it involves a complex reaction and a multi-component system. By exploiting different spectroscopies, we characterize the effect on the enzymatic kinetics of cluster formation of CyaY, the bacterial ortholog of frataxin, on cluster formation on the scaffold protein IscU. Frataxin/CyaY is a highly conserved protein implicated in an incurable ataxia in humans. Previous studies had suggested a role of CyaY as an inhibitor of iron sulfur cluster formation. Similar studies on the eukaryotic proteins have however suggested for frataxin a role as an activator. Our studies independently confirm that CyaY slows down the reaction and shed new light onto the mechanism by which CyaY works. We observe that the presence of CyaY does not alter the relative ratio between [2Fe2S]2+ and [4Fe4S]2+ but directly affects enzymatic activity

    Search for the neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at root s=7 TeV with the ATLAS detector

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    A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb-1 to 4.8 fb-1. Higgs boson decays into oppositely-charged muon or τ lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits are for the production cross-section of a generic neutral Higgs boson, φ, as a function of the Higgs boson mass and for h/A/H production in the MSSM as a function of the parameters mA and tan β in the mhmax scenario for mA in the range of 90GeV to 500 GeV. Copyright CERN

    Structural bases for the interaction of frataxin with the central components of iron–sulphur cluster assembly

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    Reduced levels of frataxin, an essential protein of as yet unknown function, are responsible for causing the neurodegenerative pathology Friedreich's ataxia. Independent reports have linked frataxin to iron–sulphur cluster assembly through interactions with the two central components of this machinery: desulphurase Nfs1/IscS and the scaffold protein Isu/IscU. In this study, we use a combination of biophysical methods to define the structural bases of the interaction of CyaY (the bacterial orthologue of frataxin) with the IscS/IscU complex. We show that CyaY binds IscS as a monomer in a pocket between the active site and the IscS dimer interface. Recognition does not require iron and occurs through electrostatic interactions of complementary charged residues. Mutations at the complex interface affect the rates of enzymatic cluster formation. CyaY binding strengthens the affinity of the IscS/IscU complex. Our data suggest a new paradigm for understanding the role of frataxin as a regulator of IscS functions

    Thermal effects on chemical diffusion in multicomponent ionic systems

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    A theoretical formulation for diffusion of multiple ions is presented in this paper which considers the effects of electrochemical and thermal diffusion potentials. The work presented is of relevance to applications such as the geological disposal of high level radioactive waste, where limited experimental information is available on ionic transfer in compacted clay buffer under non-isothermal conditions. The proposed approach incorporates the overall charge conservation in the formulation of multicomponent chemical diffusion. Thermal diffusion, i.e. Soret effect is studied in more detail by considering an explicit approach to include this process in the formulation. A detailed description of the theoretical developments is provided. A series of simulations using the proposed formulation is presented which involves pure diffusion of multiple ions under thermal gradients. The results are compared with experimental data reported in literature

    Thermal Effects on Chemical Diffusion in Multicomponent Ionic Systems

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    A theoretical formulation for diffusion of multiple ions is presented in this paper which considers the effects of electrochemical and thermal diffusion potentials. The work presented is of relevance to applications such as the geological disposal of high level radioactive waste, where limited experimental information is available on ionic transfer in compacted clay buffer under non-isothermal conditions. The proposed approach incorporates the overall charge conservation in the formulation of multicomponent chemical diffusion. Thermal diffusion, i.e. Soret effect is studied in more detail by considering an explicit approach to include this process in the formulation. A detailed description of the theoretical developments is provided. A series of simulations using the proposed formulation is presented which involves pure diffusion of multiple ions under thermal gradients. The results are compared with experimental data reported in literature

    Post-translational modification by cysteine protects Cu/Zn-superoxide dismutase from oxidative damage

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    Reactive oxygen species (ROS) are cytotoxic. To remove ROS, cells have developed ROS-specific defense mechanisms, including the enzyme Cu/Zn superoxide dismutase (SOD1), which catalyzes the disproportionation of superoxide anions into molecular oxygen and hydrogen peroxide. Although hydrogen peroxide is less reactive than superoxide, it is still capable of oxidizing, unfolding, and inactivating SOD1, at least in vitro. To explore the relevance of post-translational modification (PTM) of SOD1, including peroxide-related modifications, SOD1 was purified from postmortem human nervous tissue. As much as half of all purified SOD1 protein contained non-native post-translational modifications (PTMs), the most prevalent modifications being cysteinylation and peroxide-related oxidations. Many PTMs targeted a single reactive SOD1 cysteine, Cys<sub>111</sub>. An intriguing observation was that unlike native SOD1, cysteinylated SOD1 was not oxidized. To further characterize how cysteinylation may protect SOD1 from oxidation, cysteine-modified SOD1 was prepared in vitro and exposed to peroxide. Cysteinylation conferred nearly complete protection from peroxide-induced oxidation of SOD1. Moreover, SOD1 that has been cysteinylated and peroxide oxidized in vitro comprised a set of PTMs that bear a striking resemblance to the myriad of PTMs observed in SOD1 purified from human tissue. 2013 American Chemical Societ

    Molecular imaging of drug transit through the blood-brain barrier with MALDI mass spectrometry imaging

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    Drug transit through the blood-brain barrier (BBB) is essential for therapeutic responses in malignant glioma. Conventional methods for assessment of BBB penetrance require synthesis of isotopically labeled drug derivatives. Here, we report a new methodology using matrix assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) to visualize drug penetration in brain tissue without molecular labeling. In studies summarized here, we first validate heme as a simple and robust MALDI MSI marker for the lumen of blood vessels in the brain. We go on to provide three examples of how MALDI MSI can provide chemical and biological insights into BBB penetrance and metabolism of small molecule signal transduction inhibitors in the brain - insights that would be difficult or impossible to extract by use of radiolabeled compound
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