179 research outputs found

    The value of political connections: evidence from China's anti-corruption campaign

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    We study the value of the political connections of directors on Chinese boards. We build a new dataset that measures connections of directors to members of the Politburo via past school ties, and find that private firms with politically connected directors in the boardroom get on average about 16% higher subsidies over sales per firm (7 million yuan). Connected state-owned enterprises (SOEs) access debt at 11% cheaper cost, which translates into average savings of close to 32 million yuan per firm in lower interest payments. We find that the value of the political connections persisted after the anti-corruption campaign (ACC) of 2012. It became weaker for the cost of debt in SOEs, but stronger for subsidies to private firms. We argue that the value of connections in the private sector increased after the ACC because they became a less risky alternative to corruption. We also show that connected firms do not perform better.info:eu-repo/semantics/publishedVersio

    The value of political connections: Evidence from China's Anti-Corruption Campaign

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    We study the value of the political connections of directors on Chinese boards. We build a new dataset that measures connections of directors to members of the Politburo via past school ties, and find that private firms with politically connected directors in the boardroom get on average about 16% higher subsidies over sales per firm (7 million yuan). Connected state-owned enterprises access debt at 11% cheaper cost, which translates into average savings of close to 32 million yuan per firm in lower interest payments. We find that the value of the political connections persisted after the Anti-Corruption Campaign of 2012. It became weaker for the cost of debt in state-owned enterprises, but stronger for subsidies to private firms. We argue that the value of connections in the private sector increased after the Anti-Corruption Campaign because they became a less risky alternative to corruption. We also show that connected firms do not perform better.info:eu-repo/semantics/publishedVersio

    Incidental computed tomography diagnosis of a rare triad consisting of absence of coronary sinus, persistent left superior vena cava, and scimitar syndrome

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    We report a case of an unusual congenital triad consisting of absence of coronary sinus, persistent left superior vena cava and scimitar syndrome incidentally found in a CT-scan performed on a female complaining of exertional dyspnea

    Adipose-derived stem cells combined with Neuregulin-1 delivery systems for heart tissue engineering

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    Myocardial infarction (MI) is the leading cause of death worldwide and extensive research has therefore been performed to find a cure. Neuregulin-1 (NRG) is a growth factor involved in cardiac repair after MI. We previously described how biocompatible and biodegradable microparticles, which are able to release NRG in a sustained manner, represent a valuable approach to avoid problems related to the short half-life after systemic administration of proteins. The effectiveness of this strategy could be improved by combining NRG with several cytokines involved in cardiac regeneration. The present study investigates the potential feasibility of using NRG-releasing particle scaffold combined with adipose derived stem cells (ADSC) as a multiple growth factor delivery-based tissue engineering strategy for implantation in the infarcted myocardium. NRG-releasing particle scaffolds with a suitable size for intramyocardial implantation were prepared by TROMS. Next, ADSC were adhered to particle scaffolds and their potential for heart administration was assessed in a MI rat model. NRG was successfully encapsulated reaching encapsulation efficiencies of 92.58 ± 3.84 %. NRG maintained its biological activity after the microencapsulation process. ADSC cells adhered efficiently to particle scaffolds within a few hours. The ADSC-cytokine delivery system developed proved to be compatible with intramyocardial administration in terms of injectability through a 23-gauge needle and tissue response. Interestingly, ADSC-scaffolds were present in the peri-infarted tissue two weeks after implantation. This proof of concept study provides important evidence required for future effectiveness studies and for the translation of this approach

    Arco aórtico derecho, divertículo de Kommerell y arteria subclavia izquierda aberrante

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    The right aberrant subclavian artery or "arteria lusoria" is the most common anatomical variant of the embryonic development of the aorta and its branches, with a presence in 0.5-2% of the population. Less frequently, a right aortic arch with aberrant left subclavian artery may be present. These anatomical variations should be included in the differential diagnosis of superior mediastinal widening seen on chest radiographs. In this report, we present a right aortic arch with left aberrant subclavian artery dilated at its origin (Kommerell's diverticulum) as a cause of superior mediastinal widening detected incidentally on a chest radiograph

    Injectable alginate hydrogel loaded with GDNF promotes functional recovery in a hemisection model of spinal cord injury

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    We hypothesized that local delivery of GDNF in spinal cord lesion via an injectable alginate hydrogel gelifying in situ would support spinal cord plasticity and functional recovery. The GDNF release from the hydrogel was slowed by GDNF encapsulation in microspheres compared to non-formulated GDNF (free GDNF). When injected in a rat spinal cord hemisection model, more neurofilaments were observed in the lesion when the rats were treated with free GDNF-loaded hydrogels. More growing neurites were detected in the tissues surrounding the lesion when the animals were treated with GDNF microsphere-loaded hydrogels. Intense GFAP (astrocytes), low III tubulin (neural cells) and RECA-1 (endothelial cells) stainings were observed for non-treated lesions while GDNF-treated spinal cords presented less GFAP staining and more endothelial and nerve fiber infiltration in the lesion site. The animals treated with free GDNF-loaded hydrogel presented superior functional recovery compared with the animals treated with the GDNF microsphere-loaded hydrogels and non-treated animals

    PEGylated-PLGA microparticles containing VEGF for long term drug delivery

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    The potential of poly(lactic-co-glycolic) acid (PLGA) microparticles as carriers for vascular endothelial growth factor (VEGF) has been demonstrated in a previous study by our group, where we found improved angiogenesis and heart remodeling in a rat myocardial infarction model (Formiga et al., 2010). However, the observed accumulation of macrophages around the injection site suggested that the efficacy of treatment could be reduced due to particle phagocytosis. The aim of the present study was to decrease particle phagocytosis and consequently improve protein delivery using stealth technology. PEGylated microparticles were prepared by the double emulsion solvent evaporation method using TROMS (Total Recirculation One Machine System). Before the uptake studies in monocyte-macrophage cells lines (J774 and Raw 264.7), the characterization of the microparticles developed was carried out in terms of particle size, encapsulation efficiency, protein stability, residual poly(vinyl alcohol) (PVA) and in vitro release. Microparticles of suitable size for intramyocardial injection (5 mu m) were obtained by TROMS by varying the composition of the formulation and TROMS conditions with high encapsulation efficiency (70-90%) and minimal residual PVA content (0.5%). Importantly, the bioactivity of the protein was fully preserved. Moreover, PEGylated microparticles released in phosphate buffer 50% of the entrapped protein within 4 h, reaching a plateau within the first day of the in vitro study. Finally, the use of PLGA microparticles coated with PEG resulted in significantly decreased uptake of the carriers by macrophages, compared with non PEGylated microparticles, as shown by flow cytometry and fluorescence microscopy. On the basis of these results, we concluded that PEGylated microparticles loaded with VEGF could be used for delivering growth factors in the myocardium

    Polymeric electrospun scaffolds: neuregulin encapsulation and biocompatibility studies in a model of myocardial ischemia

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    Cardiovascular disease represents one of the major health challenges in modern times and is the number one cause of death globally. Thus, numerous studies are under way to identify effective cell‐ and/or growth factor‐based therapies for repairing damaged cardiac tissue. In this regard, improving the engraftment or survival of regenerative cells and prolonging growth factor exposure have become fundamental goals in advancing these therapeutic approaches. Biomaterials have emerged as innovative scaffolds for the delivery of both cells and proteins in tissue engineering applications. In the present study, electrospinning was used to generate smooth homogenous polymeric fibers, which consisted of a PLGA/NCO‐sP(EO‐stat‐PO) polymer blend encapsulating the cardioactive growth factor, Neuregulin‐1 (Nrg). We evaluated the biocompatibility and degradation of this Nrg‐containing biomaterial in a rat model of myocardial ischemia. Histological analysis revealed the presence of an initial acute inflammatory response after implantation, which was followed by a chronic inflammatory phase, characterized by the presence of giant cells. Notably, the scaffold remained in the heart after 3 months. Furthermore, an increase in the M2:M1 macrophage ratio following implantation suggested the induction of constructive tissue remodeling. Taken together, the combination of Nrg‐encapsulating scaffolds with cells capable of inducing cardiac regeneration could represent an ambitious and promising therapeutic strategy for repairing diseased or damaged myocardial tissue

    Sustained release of VEGF through PLGA microparticles improves vasculogenesis and tissue remodeling in an acute myocardial ischemia–reperfusion model

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    The use of pro-angiogenic growth factors in ischemia models has been associated with limited success in the clinical setting, in part owing to the short lived effect of the injected cytokine. The use of a microparticle system could allow localized and sustained cytokine release and consequently a prolonged biological effect with induction of tissue revascularization. To assess the potential of VEGF165 administered as continuous release in ischemic disease, we compared the effect of delivery of poly(lactic–co-glycolic acid) (PLGA) microparticles (MP) loaded with VEGF165 with free-VEGF or control empty microparticles in a rat model of ischemia–reperfusion. VEGF165 loaded microparticles could be detected in the myocardium of the infarcted animals for more than a month after transplant and provided sustained delivery of active protein in vitro and in vivo. One month after treatment, an increase in angiogenesis (small caliber caveolin-1 positive vessels) and arteriogenesis (α-SMA-positive vessels) was observed in animals treated with VEGF microparticles (pb0.05), but not in the empty microparticles or free-VEGF groups. Correlating with this data, a positive remodeling of the heart was also detected in the VEGF-microparticle group with a significantly greater LV wall thickness (pb0.01). In conclusion, PLGA microparticle is a feasible and promising cytokine delivery system for treatment of myocardial ischemia. This strategy could be scaled up and explored in pre-clinical and clinical studies

    Biodegradation and heart retention of polymeric microparticles in a rat model of myocardial ischemia

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    Poly-lactide-co-glycolide (PLGA) microparticles emerged as one of the most promising strategies to achieve site-specific drug delivery. Although these microparticles have been demonstrated to be effective in several wound healing models, their potential in cardiac regeneration has not yet been fully assessed. The present work sought to explore PLGA microparticles as cardiac drug delivery systems. PLGA microparticles were prepared by Total Recirculation One-Machine System (TROMS) after the formation of a multiple emulsion. Microparticles of different size were prepared and characterized to select the most suitable size for intramyocardial administration. Next, the potential of PLGA microparticles for administration in the heart was assessed in a MI rat model. Particle biodegradation over time and myocardial tissue reaction were studied by routine staining and confocal microscopy. Results showed that microparticles with a diameter of 5 μm were the most compatible with intramyocardial administration in terms of injectability through a 29-gauge needle and tissue response. Particles were present in the heart tissue for up to three months post-implantation and no particle migration towards other solid organs was observed, demonstrating good myocardial retention. CD68 immunolabeling revealed 31%, 47% and below 4% microparticle uptake by macrophages one week, one month and three months after injection, respectively (P<0.001). Taken together, these findings support the feasibility of the developed PLGA microparticles as vehicles for delivering growth factors in the infarcted myocardium
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