1,629 research outputs found

    Out of Africa: The role of institutional distance and host-home colonial tie in South African Firms’ post-acquisition performance in developed economies

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    The colonial ties and institutional distance affect the cross-border acquisition performance of internationalizing South African firms who acquire targets in developed economies. Along with these main effects, this paper examines the moderating effect of the colonial tie on the effects of institutional distance on post-acquisition long-term operating performance. Using data on South African acquisitions in developed economies, this study finds that the colonial tie has a negative impact on the long-term operating performance of South African acquirers. Yet, the colonial tie also moderates the effects of institutional distance. This work contributes to the discussion on host-home country institutional distance and its impact on post-acquisition long-term operating performance and how colonial past can influence the performance of acquirers from South Africa and other such countries with colonial history

    Age Matters: The Contingency of Economic Distance and Economic Freedom in Emerging Market Firm’s Cross-Border M&A Performance

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    The primary studies on emerging market multinational firms (EMFs) thus far have depicted a picture of accelerated internationalization in which EMFs conduct a series of aggressive cross-border acquisitions to further enhance their competitive advantage. However, it is not clear whether the EMFs which conducted the acquisitions at a young age experience better performance. EMFs constrained by their home market development in economic institutions may encounter different challenges in their cross-border acquisitions. Using a sample of South African firms’ acquisitions between 1994 and 2012, we find support for the benefit of foreign acquisitions at a young age as well as the moderation effects of economic distance and economic freedom. While early inorganic growth provides an excellent opportunity to propel South African firms’ growth, the country level factors present important boundary conditions to examine the benefit of early internationalization. While facing a significant economic distance, older firms are better at utilizing their experience and experience better post-acquisition operating performance. By contrast, the younger firms benefit more from the post-acquisition when the home country has weaker economic freedom

    Gap junction proteins and their role in spinal cord injury

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    © 2015 Tonkin, Mao, O'Carroll, Nicholson, Green, Gorrie and Moalem-Taylor. Gap junctions are specialized intercellular communication channels that are formed by two hexameric connexin hemichannels, one provided by each of the two adjacent cells. Gap junctions and hemichannels play an important role in regulating cellular metabolism, signaling, and functions in both normal and pathological conditions. Following spinal cord injury (SCI), there is damage and disturbance to the neuronal elements of the spinal cord including severing of axon tracts and rapid cell death. The initial mechanical disruption is followed by multiple secondary cascades that cause further tissue loss and dysfunction. Recent studies have implicated connexin proteins as playing a critical role in the secondary phase of SCI by propagating death signals through extensive glial networks. In this review, we bring together past and current studies to outline the distribution, changes and roles of various connexins found in neurons and glial cells, before and in response to SCI. We discuss the contribution of pathologically activated connexin proteins, in particular connexin 43, to functional recovery and neuropathic pain, as well as providing an update on potential connexin specific pharmacological agents to treat SCI

    Microarray studies reveal novel genes associated with endocrine resistance in breast cancer

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    Background Endocrine resistance is a major hurdle in breast cancer management, and determining the underlying factors driving its growth and aggressive behaviour should vastly improve treatment. Methods Microarray technology (BD Atlas Plastic Human 12 K Microarrays; GeneSifter software), verified by PCR, western blotting and immunocytochemisty, was used to identify genes increased in acquired resistant models to tamoxifen (TamR) or faslodex (FasR) as potential predictive/prognostic markers and new therapeutic targets. Results Alongside known breast cancer genes (β-catenin, PEA3, vitronectin, CD44), two novel genes in endocrine resistance were revealed (the latter never previously described in breast cancer): a securin/cell cycle regulator Pituitary Tumour Transforming Gene-1 (PTTG1), and GDNF receptor-alpha 3 (GFRα3) reported to promote cell survival signalling via RET coreceptor. Altered levels of PTTG1, GFRα3, or their associated family members were observed in further endocrine resistant states, including an additional faslodex resistant model that has progressed to a highly-aggressive state (FasR-Lt) and XMCF-7 cells resistant to oestrogen deprivation. PTTG1 and GFRα3 induction were also implicated in limiting response to anti-EGFR agents currently in breast cancer trials, with GFRα3 ligand (artemin) largely overcoming drug response. mRNA studies in clinical disease revealed PTTG1 associated with lymph node spread, high tumour grade and proliferation, while GFRα3 was enriched in ER-negative tumours and those expressing EGFR, profiles implying roles in clinical resistance and aggressive tumour behaviour. Promisingly, PTTG1 or GFRα3 siRNA knockdown promoted cell kill and inhibited proliferation in the resistant models. Conclusion Cumulatively, these data indicate PTTG1 and GFRα3 may provide useful biomarkers, and perhaps clinically relevant therapeutic targets for multiple resistant states

    Characterisation of Peptide5 systemic administration for treating traumatic spinal cord injured rats

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    © 2017, Springer-Verlag GmbH Germany. Systemic administration of a Connexin43 mimetic peptide, Peptide5, has been shown to reduce secondary tissue damage and improve functional recovery after spinal cord injury (SCI). This study investigated safety measures and potential off-target effects of Peptide5 systemic administration. Rats were subjected to a mild contusion SCI using the New York University impactor. One cohort was injected intraperitoneally with a single dose of fluorescently labelled Peptide5 and euthanised at 2 or 4 h post-injury for peptide distribution analysis. A second cohort received intraperitoneal injections of Peptide5 or a scrambled peptide and was culled at 8 or 24 h post-injury for the analysis of connexin proteins and systemic cytokine profile. We found that Peptide5 did not cross the blood-spinal cord barrier in control animals, but reached the lesion area in the spinal cord-injured animals without entering non-injured tissue. There was no evidence that the systemic administration of Peptide5 modulates Connexin43 protein expression or hemichannel closure in the heart and lung tissue of SCI animals. The expression levels of other major connexin proteins including Connexin30 in astrocytes, Connexin36 in neurons and Connexin47 in oligodendrocytes were also unaltered by systemic delivery of Peptide5 in either the injured or non-injured spinal cords. In addition, systemic delivery of Peptide5 had no significant effect on the plasma levels of cytokines, chemokines or growth factors. These data indicate that the systemic delivery of Peptide5 is unlikely to cause any off-target or adverse effects and may thus be a safe treatment option for traumatic SCI

    Metabolic phenotyping using UPLC–MS and rapid microbore UPLC–IM–MS: determination of the effect of different dietary regimes on the urinary metabolome of the rat

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    A rapid reversed-phase gradient method employing a 50 mm × 1 mm i.d., C18 microbore column, combined with ion mobility and high-resolution mass spectrometry, was applied to the metabolic phenotyping of urine samples obtained from rats receiving different diets. This method was directly compared to a “conventional” method employing a 150 × 2.1 mm i.d. column packed with the same C18 bonded phase using the same samples. Multivariate statistical analysis of the resulting data showed similar class discrimination for both microbore and conventional methods, despite the detection of fewer mass/retention time features by the former. Multivariate statistical analysis highlighted a number of ions that represented diet-specific markers in the samples. Several of these were then identified using the combination of mass, ion-mobility-derived collision cross section and retention time including N-acetylglutamate, urocanic acid, and xanthurenic acid. Kynurenic acid was tentatively identified based on mass and ion mobility data
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