25 research outputs found

    TIA model is attainable in Wistar rats by intraluminal occlusion of the MCA for 10 min or shorter

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    Transient ischemic attack (TIA) has received only little attention in the experimental research field. Recently, we introduced a TIA model for mice, and here we set similar principles for simulating this human condition in Wistar rats. In the model: 1) transient nature of the event is ensured, and 2) 24 h after the event animals are free from any sensorimotor deficit and from any detectable lesion by magnetic resonance imaging (MRI). Animals experienced varying durations of ischemia (5, 10, 12.5, 15, 25, and 30 min, n = 6-8 per group) by intraluminal middle cerebral artery occlusion (MCAO). Ischemia severity and reperfusion rates were controlled by cerebral blood flow measurements. Sensorimotor neurological evaluations and MRI at 24 h differentiated between TIA and ischemic stroke. Hematoxylin and eosin staining and apoptotic cell counts revealed pathological correlates of the event. We found that already 12.5 min of ischemia was long enough to induce ischemic stroke in Wistar rats. Ten min or shorter durations induced neither gross neurological deficits nor infarcts visible on MRI, but histologically caused selective neuronal necrosis. A separate group of animals with 10 min of ischemia followed up to 1 week after reperfusion remained free of infarction and any MRI signal change. Thus, 10 min or shorter focal cerebral ischemia induced by intraluminal MCAO in Wistar rats provides a clinically relevant TIA the rat. This model is useful for studying molecular correlates of TIA. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

    Ambient Air Pollution, Social Inequalities and Asthma Exacerbation in Greater Strasbourg (France) Metropolitan Area: the PAISA Study

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    International audienceThe socio-economic status (SES) of populations has an influence on the incidence or mortality rates of numerous health outcomes, among which respiratory diseases (Prescott et al., 2003; Ellison-Loschmann et al., 2007). Considering asthma, the possible contribution of SES to overall prevalence –regardless of asthma severity-, remains controversial in industrialized countries. Several studies indicate that allergic asthma is more prevalent in more well-off populations whereas the non-allergic forms of asthma are more common in the deprived ones (Cesaroni et al., 2003; Blanc et al., 2006). On the other hand, severe asthma whatever its etiology appears to be more frequent in the latter populations, as compared to the more affluent (Basagana et al., 2004). Risk factors for exacerbations (e.g., passive smoking (Wright Subramanian, 2007), psychosocial stress (Gold & Wright, 2005), cockroach allergens (Kitch et al., 2000), and suboptimal compliance with anti-inflammatory medication (Gottlieb et al., 1995)) are generally more common among people with asthma and low SES than their better-off counterparts. These observations support the hypothesis that some factors more present in deprived populations contribute to asthma exacerbation (Mielck et al., 1996)

    Thermosensitive polymer-grafted iron oxide nanoparticles studied by in situ dynamic light backscattering under magnetic hyperthermia

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    © 2015 IOP Publishing Ltd. Thermometry at the nanoscale is an emerging area fostered by intensive research on nanoparticles (NPs) that are capable of converting electromagnetic waves into heat. Recent results suggest that stationary gradients can be maintained between the surface of NPs and the bulk solvent, a phenomenon sometimes referred to as \u27cold hyperthermia\u27. However, the measurement of such highly localized temperatures is particularly challenging. We describe here a new approach to probing the temperature at the surface of iron oxide NPs and enhancing the understanding of this phenomenon. This approach involves the grafting of thermosensitive polymer chains to the NP surface followed by the measurement of macroscopic properties of the resulting NP suspension and comparison to a calibration curve built up by macroscopic heating. Superparamagnetic iron oxide NPs were prepared by the coprecipitation of ferrous and ferric salts and functionalized with amines, then azides using a sol-gel route followed by a dehydrative coupling reaction. Thermosensitive poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) with an alkyne end-group was synthesized by controlled radical polymerization and was grafted using a copper assisted azide-alkyne cycloaddition reaction. Measurement of the colloidal properties by dynamic light scattering (DLS) indicated that the thermosensitive NPs exhibited changes in their Zeta potential and hydrodynamic diameter as a function of pH and temperature due to the grafted PDMAEMA chains. These changes were accompanied by changes in the relaxivities of the NPs, suggesting application as thermosensitive contrast agents for magnetic resonance imaging (MRI). In addition, a new fibre-based backscattering setup enabled positioning of the DLS remote-head as close as possible to the coil of a magnetic heating inductor to afford in situ probing of the backscattered light intensity, hydrodynamic diameter, and temperature. This approach provides a promising platform for estimating the response of magnetic NPs to application of a radiofrequency magnetic field or for understanding the behaviour of other thermogenic NPs

    The Welfare Implications of Using Exotic Tortoises as Ecological Replacements

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    <div><h3>Background</h3><p>Ecological replacement involves the introduction of non-native species to habitats beyond their historical range, a factor identified as increasing the risk of failure for translocations. Yet the effectiveness and success of ecological replacement rely in part on the ability of translocatees to adapt, survive and potentially reproduce in a novel environment. We discuss the welfare aspects of translocating captive-reared non-native tortoises, <em>Aldabrachelys gigantea</em> and <em>Astrochelys radiata</em>, to two offshore Mauritian islands, and the costs and success of the projects to date.</p> <h3>Methodology/Principal Findings</h3><p>Because tortoises are long-lived, late-maturing reptiles, we assessed the progress of the translocation by monitoring the survival, health, growth, and breeding by the founders. Between 2000 and 2011, a total of 26 <em>A. gigantea</em> were introduced to Ile aux Aigrettes, and in 2007 twelve sexually immature <em>A. gigantea</em> and twelve male <em>A. radiata</em> were introduced to Round Island, Mauritius. Annual mortality rates were low, with most animals either maintaining or gaining weight. A minimum of 529 hatchlings were produced on Ile aux Aigrettes in 11 years; there was no potential for breeding on Round Island. Project costs were low. We attribute the success of these introductions to the tortoises’ generalist diet, habitat requirements, and innate behaviour.</p> <h3>Conclusions/Significance</h3><p>Feasibility analyses for ecological replacement and assisted colonisation projects should consider the candidate species’ welfare during translocation and in its recipient environment. Our study provides a useful model for how this should be done. In addition to serving as ecological replacements for extinct Mauritian tortoises, we found that releasing small numbers of captive-reared <em>A. gigantea</em> and <em>A. radiata</em> is cost-effective and successful in the short term. The ability to release small numbers of animals is a particularly important attribute for ecological replacement projects since it reduces the potential risk and controversy associated with introducing non-native species.</p> </div

    Intended Consequences Statement in Conservation Science and Practice

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    As the biodiversity crisis accelerates, the stakes are higher for threatened plants and animals. Rebuilding the health of our planet will require addressing underlying threats at many scales, including habitat loss and climate change. Conservation interventions such as habitat protection, management, restoration, predator control, trans location, genetic rescue, and biological control have the potential to help threatened or endangered species avert extinction. These existing, well-tested methods can be complemented and augmented by more frequent and faster adoption of new technologies, such as powerful new genetic tools. In addition, synthetic biology might offer solutions to currently intractable conservation problems. We believe that conservation needs to be bold and clear-eyed in this moment of great urgency

    Local Extinction in the Bird Assemblage in the Greater Beijing Area from 1877 to 2006

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    Recent growth in industrialization and the modernization of agricultural activities, combined with human population growth, has greatly modified China’s natural environment, particularly in the vicinity of large cities. We compared avifauna checklists made between 1877 and 1938 with current checklists to determine the extent of local bird extinctions during the last century in the greater Beijing area. Our study shows that of the 411 bird species recorded from 1877–1938, 45 (10.9%) were no longer recorded from 2004–2006. Birds recorded as ‘rare’ in 1938 were more likely to have disappeared in subsequent years. Migrant status also influenced the probability of local bird extinction with winter migrants being the most affected class. Moreover, larger birds were more likely to have disappeared than smaller ones, potentially explained by differential ecological requirements and anthropogenic exploitation. Although our habitat descriptions and diet classification were not predictors of local bird extinction, the ecological processes driving local bird extinction are discussed in the light of historical changes that have impacted this region since the end of the 1930 s. Our results are of importance to the broader conservation of bird wildlife

    Trade in live reptiles, its impact on wild populations, and the role of the European market

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    Of the 10,272 currently recognized reptile species, the trade of fewer than 8% are regulated by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the European Wildlife Trade Regulations (EWTR). However, the International Union for Conservation of Nature (IUCN) Red List has assessed 45% of the world's reptile species and determined that at least 1390 species are threatened by “biological resource use”. Of these, 355 species are intentionally targeted by collectors, including 194 non-CITES-listed species. Herein we review the global reptile pet trade, its impacts, and its contribution to the over-harvesting of species and populations, in light of current international law. Findings are based on an examination of relevant professional observations, online sources, and literature (e.g., applicable policies, taxonomy [reptile database], trade statistics [EUROSTAT], and conservation status [IUCN Red List]). Case studies are presented from the following countries and regions: Australia, Central America, China, Galapagos Islands (Ecuador), Germany, Europe, India, Indonesia (Kalimantan), Islamic Republic of Iran, Japan, Madagascar, Mexico, New Zealand, the Philippines, South Africa, Sri Lanka, Vietnam, Western Africa, and Western Asia. The European Union (EU) plays a major role in reptile trade. Between 2004 and 2014 (the period under study), the EU member states officially reported the import of 20,788,747 live reptiles. This review suggests that illegal trade activities involve species regulated under CITES, as well as species that are not CITES-regulated but nationally protected in their country of origin and often openly offered for sale in the EU. Further, these case studies demonstrate that regulations and enforcement in several countries are inadequate to prevent the overexploitation of species and to halt illegal trade activities

    Hi5: A versatile dual-wrist device to study human-human interaction and bimanual control

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    Our goal is to investigate the mechanisms of human-human interaction in collaborative and competitive tasks. In this regard, previous groups have suggested simplified motor tasks involving dual robotic interfaces. However, these interfaces involved arm movements with a high degree of kinematic and muscle redundancy. This paper introduces a simple, yet versatile dual-wrist robotic interface, Hi5, that allows us to investigate the motor processes behind human-human and bimanual interaction control, and avoid confounds inherent of arm movements. This paper presents the design of Hi5 and the implemented safety measures. Performance tests then demonstrate its capacity to yield high dynamics, and exhibit low values for inertia and friction. Preliminary experiments show how Hi5 allows us to analyze the specific kinematic, torque and muscle activation patterns of each partner and disambiguate their roles in force and impedance control

    TIA model is attainable in Wistar rats by intraluminal occlusion of the MCA for 10 min or shorter

    No full text
    Transient ischemic attack (TIA) has received only little attention in the experimental research field. Recently, we introduced a TIA model for mice, and here we set similar principles for simulating this human condition in Wistar rats. In the model: 1) transient nature of the event is ensured, and 2) 24 h after the event animals are free from any sensorimotor deficit and from any detectable lesion by magnetic resonance imaging (MRI). Animals experienced varying durations of ischemia (5, 10, 12.5, 15, 25, and 30 min, n = 6–8 per group) by intraluminal middle cerebral artery occlusion (MCAO). Ischemia severity and reperfusion rates were controlled by cerebral blood flow measurements. Sensorimotor neurological evaluations and MRI at 24 h differentiated between TIA and ischemic stroke. Hematoxylin and eosin staining and apoptotic cell counts revealed pathological correlates of the event. We found that already 12.5 min of ischemia was long enough to induce ischemic stroke in Wistar rats. Ten min or shorter durations induced neither gross neurological deficits nor infarcts visible on MRI, but histologically caused selective neuronal necrosis. A separate group of animals with 10 min of ischemia followed up to 1 week after reperfusion remained free of infarction and any MRI signal change. Thus, 10 min or shorter focal cerebral ischemia induced by intraluminal MCAO in Wistar rats provides a clinically relevant TIA the rat. This model is useful for studying molecular correlates of TIA. © 2017 Elsevier B.V

    Developing a data-driven spatial approach to assessment of neighbourhood influences on the spatial distribution of myocardial infarction

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    Abstract Background There is a growing understanding of the role played by ‘neighbourhood’ in influencing health status. Various neighbourhood characteristics—such as socioeconomic environment, availability of amenities, and social cohesion, may be combined—and this could contribute to rising health inequalities. This study aims to combine a data-driven approach with clustering analysis techniques, to investigate neighbourhood characteristics that may explain the geographical distribution of the onset of myocardial infarction (MI) risk. Methods All MI events in patients aged 35–74 years occurring in the Strasbourg metropolitan area (SMA), from January 1, 2000 to December 31, 2007 were obtained from the Bas-Rhin coronary heart disease register. All cases were geocoded to the census block for the residential address. Each areal unit, characterized by contextual neighbourhood profile, included socioeconomic environment, availability of amenities (including leisure centres, libraries and parks, and transport) and psychosocial environment as well as specific annual rates standardized (per 100,000 inhabitants). A spatial scan statistic implemented in SaTScan was then used to identify statistically significant spatial clusters of high and low risk of MI. Result MI incidence was non-randomly spatially distributed, with a cluster of high risk of MI in the northern part of the SMA [relative risk (RR) = 1.70, p = 0.001] and a cluster of low risk of MI located in the first and second periphery of SMA (RR 0.04, p value  =  0.001). Our findings suggest that the location of low MI risk is characterized by a high socioeconomic level and a low level of access to various amenities; conversely, the location of high MI risk is characterized by a high level of socioeconomic deprivation—despite the fact that inhabitants have good access to the local recreational and leisure infrastructure. Conclusion Our data-driven approach highlights how the different contextual dimensions were inter-combined in the SMA. Our spatial approach allowed us to identify the neighbourhood characteristics of inhabitants living within a cluster of high versus low MI risk. Therefore, spatial data-driven analyses of routinely-collected data georeferenced by various sources may serve to guide policymakers in defining and promoting targeted actions at fine spatial level
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