389 research outputs found

    Defining the most effective patient blood management combined with tranexamic acid regime in primary uncemented total hip replacement surgery

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    The application of patient blood management (PBM) combined with tranexamic acid administration (TXA) results in decreased total blood loss volume (TVB) and transfusions in total hip replacements (THRs). Dosages, timing, and routes of administration of TXA are still under debate as all these aspects, as well as interpatient variations, may a ect the e cacy of the protocol. This study aims to examine the e ectiveness of timing and route of administration of TXA in combination with PBM by reducing the TBV following THR surgery. Consecutive primary uncemented THRs operated by a single surgical and anaesthetic team had the data prospectively collected and then retrospectively studied. Five treatment groups were formed, reflecting the progressive evolution of our protocol. Group 1 included patients managed with PBM alone (preoperative erythrocyte mass optimisation to at least 14 g/dL haemoglobin (Hb), hypotensive spinal anaesthesia and restrictive red blood cell transfusion criteria). Group 2 included patients with PBM and topical 3 g TXA diluted in normal saline to a total volume of 50 mL. Group 3 were patients with PBM and an IV dose of 20 mg/kg TXA at induction, followed by 20 mg/kg TXA as a continuous infusion for the duration of the operation. Group 4 consisted of patients managed as per Group 3 plus another 20 mg/kg TXA at three-hour post-procedure. Group 5 (combined): PBM and IV TXA as per Group 4 and topical TXA as per Group 2. A generalised linear model with the treatment group as an independent variable was modelled, using TBV as the dependent variable. The transfusion rate for all groups was 0%. TBV at 24 h, oscillated from 613.5 337.63 mL in Group 1 to 376.29 135.0 mL in Group 5. TBV at 48 h oscillated from 738.3 367.3 mL (PBM group) to 434 155.2 mL (PBM + combined group). The multivariate regression model confirmed a significant decrease of TBV in all groups with TXA compared with the PBM-only group. Overweight and preoperative Hb were confirmed to significantly influence TBV. The optimal regime to achieve the least TBV and a transfusion rate of 0% requires PBM and one loading 20 mg/kg dose of TXA, followed by continuous infusion of 20 mg/kg for the duration of the operation in uncemented THRs. Additional doses of TXA did not add a clear benefi

    Tropological space : the imaginary space of figuration

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    The paper is devoted to the concept of tropological space, introduced by Michel Foucault in 1966 and alluded to in Hayden White’s tropics of discourse (1973, 1978, 2000), but never described in any detail in literary semantics or linguistic stylistics. The author presents her theory of a triple functional subdivision of stylistic figures and, consequently, of tropes (micro-, macro- and mega (meta)-level of description) and relates it to a gradually expanding tropological space of particular figures, their chains and groupings within a text. The author postulates that tropological space, the imaginary space created through figuration, is a sub-space of the Wittgensteinian logical space as well as a sub-space of textual / discursive space. Although the discussion refers mostly to literary texts, tropology – a branch of stylistics / poetics / rhetoric makes generalizations valid for the study of all kinds of texts / discourses. Figuration is assumed here to be an inherent feature of conceptual and linguistic expression. Finally, the author raises a methodological query as to the ontological status of tropological space, opting for the approach which treats it as a peculiar kind of semantic space rather than a mere metaphoric term. The discussion is based mostly on the Anglo-American studies on figuration (K. Burke, H. White, P. de Man, J. Hillis Miller, G. Hartman) that are rooted in the neo-classical rhetoric and writings of G. Vico. This line of thinking draws its philosophical inspiration from the European hermeneutics of P. Ricoeur, the Foucaultian theory of discourses and the Derridean deconstructionist ideas on the operation of language. The author brings additionally into consideration the conception of artistic space propagated by the Russian semiotic tradition and V. N. Toporov (1983/2003) in particular

    The novel gene Ny-1 on potato chromosome IX confers hypersensitive resistance to Potato virus Y and is an alternative to Ry genes in potato breeding for PVY resistance

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    Hypersensitive resistance (HR) is an efficient defense strategy in plants that restricts pathogen growth and can be activated during host as well as non-host interactions. HR involves programmed cell death and manifests itself in tissue collapse at the site of pathogen attack. A novel hypersensitivity gene, Ny-1, for resistance to Potato virus Y (PVY) was revealed in potato cultivar Rywal. This is the first gene that confers HR in potato plants both to common and necrotic strains of PVY. The locus Ny-1 mapped on the short arm of potato chromosome IX, where various resistance genes are clustered in Solanaceous genomes. Expression of HR was temperature-dependent in cv. Rywal. Strains PVYO and PVYN, including subgroups PVYNW and PVYNTN, were effectively localized when plants were grown at 20°C. At 28°C, plants were systemically infected but no symptoms were observed. In field trials, PVY was restricted to the inoculated leaves and PVY-free tubers were produced. Therefore, the gene Ny-1 can be useful for potato breeding as an alternative donor of PVY resistance, because it is efficacious in practice-like resistance conferred by Ry genes

    The MRN complex is transcriptionally regulated by MYCN during neural cell proliferation to control replication stress

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    The MRE11/RAD50/NBS1 (MRN) complex is a major sensor of DNA double strand breaks, whose role in controlling faithful DNA replication and preventing replication stress is also emerging. Inactivation of the MRN complex invariably leads to developmental and/or degenerative neuronal defects, the pathogenesis of which still remains poorly understood. In particular, NBS1 gene mutations are associated with microcephaly and strongly impaired cerebellar development, both in humans and in the mouse model. These phenotypes strikingly overlap those induced by inactivation of MYCN, an essential promoter of the expansion of neuronal stem and progenitor cells, suggesting that MYCN and the MRN complex might be connected on a unique pathway essential for the safe expansion of neuronal cells. Here, we show that MYCN transcriptionally controls the expression of each component of the MRN complex. By genetic and pharmacological inhibition of the MRN complex in a MYCN overexpression model and in the more physiological context of the Hedgehog-dependent expansion of primary cerebellar granule progenitor cells, we also show that the MRN complex is required for MYCN-dependent proliferation. Indeed, its inhibition resulted in DNA damage, activation of a DNA damage response, and cell death in a MYCN- and replication-dependent manner. Our data indicate the MRN complex is essential to restrain MYCN-induced replication stress during neural cell proliferation and support the hypothesis that replication-born DNA damage is responsible for the neuronal defects associated with MRN dysfunctions.Cell Death and Differentiation advance online publication, 12 June 2015; doi:10.1038/cdd.2015.81

    A functional peptidyl-tRNA hydrolase, ICT1, has been recruited into the human mitochondrial ribosome

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    Bioinformatic analysis classifies the human protein encoded by immature colon carcinoma transcript-1 (ICT1) as one of a family of four putative mitochondrial translation release factors. However, this has not been supported by any experimental evidence. As only a single member of this family, mtRF1a, is required to terminate the synthesis of all 13 mitochondrially encoded polypeptides, the true physiological function of ICT1 was unclear. Here, we report that ICT1 is an essential mitochondrial protein, but unlike the other family members that are matrix-soluble, ICT1 has become an integral component of the human mitoribosome. Release-factor assays show that although ICT1 has retained its ribosome-dependent PTH activity, this is codon-independent; consistent with its loss of both domains that promote codon recognition in class-I release factors. Mutation of the GGQ domain common to ribosome-dependent PTHs causes a loss of activity in vitro and, crucially, a loss of cell viability, in vivo. We suggest that ICT1 may be essential for hydrolysis of prematurely terminated peptidyl-tRNA moieties in stalled mitoribosomes

    Rap1b is critical for glycoprotein VI-mediated but not ADP receptor-mediated α 2 β 1 activation

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    The platelet α2β1 integrin functions as both an adhesion and signaling receptor upon exposure to collagen. Recent studies have indicated that α2β1 function can be activated via inside-out signaling, similar to the prototypical platelet integrin αIIbβ3. However, signaling molecules that regulate α2β1 activation in platelets are not well defined. A strong candidate molecule is the small GTPase Rap1b, the dominant platelet isoform of Rap1, which regulates αIIbβ3 activation

    A Facile Palladium Catalysed 3-Component Cascade Route to Functionalised Isoquinolinones and Isoquinolines

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    Palladium catalysed three component cascade process, involving coupling of 2-iodobenzoates, -benzaldehydes, or acetophenones with substituted allenes and ammonium tartrate as an ammonium surrogate, provides a novel and facile route to substituted functionalised isoquinolinones and isoquinolines in good yields

    Binding Properties and Stability of the Ras-Association Domain of Rap1-GTP Interacting Adapter Molecule (RIAM)

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    The Rap1-GTP interacting adapter protein (RIAM) is an important protein in Rap1-mediated integrin activation. By binding to both Rap1 GTPase and talin, RIAM recruits talin to the cell membrane, thus facilitating talin-dependent integrin activation. In this article, we studied the role of the RIAM Ras-association (RA) and pleckstrin-homology (PH) domains in the interaction with Rap1. We found that the RA domain was sufficient for GTP-dependent interaction with Rap1B, and the addition of the PH domain did not change the binding affinity. We also detected GTP-independent interaction of Rap1B with the N-terminus of RIAM. In addition, we found that the PH domain stabilized the RA domain both in vitro and in cells

    Micro-CT imaging reveals<i> Mekk3 </i>heterozygosity prevents cerebral cavernous malformations in <i>Ccm2</i>-deficient mice

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    Mutations in CCM1 (aka KRIT1), CCM2, or CCM3 (aka PDCD10) gene cause cerebral cavernous malformation in humans. Mouse models of CCM disease have been established by deleting Ccm genes in postnatal animals. These mouse models provide invaluable tools to investigate molecular mechanism and therapeutic approaches for CCM disease. However, the full value of these animal models is limited by the lack of an accurate and quantitative method to assess lesion burden and progression. In the present study we have established a refined and detailed contrast enhanced X-ray micro-CT method to measure CCM lesion burden in mouse brains. As this study utilized a voxel dimension of 9.5μm (leading to a minimum feature size of approximately 25μm), it is therefore sufficient to measure CCM lesion volume and number globally and accurately, and provide high-resolution 3-D mapping of CCM lesions in mouse brains. Using this method, we found loss of Ccm1 or Ccm2 in neonatal endothelium confers CCM lesions in the mouse hindbrain with similar total volume and number. This quantitative approach also demonstrated a rescue of CCM lesions with simultaneous deletion of one allele of Mekk3. This method would enhance the value of the established mouse models to study the molecular basis and potential therapies for CCM and other cerebrovascular diseases
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