150 research outputs found

    Afghanistan: Final Assessment Report

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    In December 2005 the European Commission (EC) performed an Assessment Mission with the overall objective of assisting the EC in designing its strategy to support the government of Afghanistan in implementing its Mine Action and Ammunition Stockpile Destruction programmes. The objective of the mission was to sketch out a strategy for landmine and ammunition stockpile destruction and contribute to its implementation

    Rapid glutamate receptor 2 trafficking during retinal degeneration

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    <p>Abstract</p> <p>Background</p> <p>Retinal degenerations, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), are characterized by photoreceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic glutamate receptor (iGluR) reprogramming in retinal degenerations, we hypothesized that the edited glutamate receptor 2 (GluR2) subunit and its trafficking may be modulated in retinal degenerations.</p> <p>Results</p> <p>Adult albino Balb/C mice were exposed to intense light for 24 h to induce light-induced retinal degeneration (LIRD). We found that prior to the onset of photoreceptor loss, protein levels of GluR2 and related trafficking proteins, including glutamate receptor-interacting protein 1 (GRIP1) and postsynaptic density protein 95 (PSD-95), were rapidly increased. LIRD triggered neuritogenesis in photoreceptor survival regions, where GluR2 and its trafficking proteins were expressed in the anomalous dendrites. Immunoprecipitation analysis showed interaction between KIF3A and GRIP1 as well as PSD-95, suggesting that KIF3A may mediate transport of GluR2 and its trafficking proteins to the novel dendrites. However, in areas of photoreceptor loss, GluR2 along with its trafficking proteins nearly vanished in retracted retinal neurites.</p> <p>Conclusions</p> <p>All together, LIRD rapidly triggers GluR2 plasticity, which is a potential mechanism behind functionally phenotypic revisions of retinal neurons and neuritogenesis during retinal degenerations.</p

    Local Synaptic Inputs Support Opposing, Network-Specific Odor Representations in a Widely Projecting Modulatory Neuron

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    Serotonin plays different roles across networks within the same sensory modality. Previously, we used whole-cell electrophysiology in Drosophila to show that serotonergic neurons innervating the first olfactory relay are inhibited by odorants (Zhang and Gaudry, 2016). Here we show that network-spanning serotonergic neurons segregate information about stimulus features, odor intensity and identity, by using opposing coding schemes in different olfactory neuropil. A pair of serotonergic neurons (the CSDns) innervate the antennal lobe and lateral horn, which are first and second order neuropils. CSDn processes in the antennal lobe are inhibited by odors in an identity independent manner. In the lateral horn, CSDn processes are excited in an odor identity dependent manner. Using functional imaging, modeling, and EM reconstruction, we demonstrate that antennal lobe derived inhibition arises from local GABAergic inputs and acts as a means of gain control on branch-specific inputs that the CSDns receive within the lateral horn

    Integration of Parallel Opposing Memories Underlies Memory Extinction.

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    Accurately predicting an outcome requires that animals learn supporting and conflicting evidence from sequential experience. In mammals and invertebrates, learned fear responses can be suppressed by experiencing predictive cues without punishment, a process called memory extinction. Here, we show that extinction of aversive memories in Drosophila requires specific dopaminergic neurons, which indicate that omission of punishment is remembered as a positive experience. Functional imaging revealed co-existence of intracellular calcium traces in different places in the mushroom body output neuron network for both the original aversive memory and a new appetitive extinction memory. Light and ultrastructural anatomy are consistent with parallel competing memories being combined within mushroom body output neurons that direct avoidance. Indeed, extinction-evoked plasticity in a pair of these neurons neutralizes the potentiated odor response imposed in the network by aversive learning. Therefore, flies track the accuracy of learned expectations by accumulating and integrating memories of conflicting events.S.W. was funded by a Wellcome Principal Research Fellowship (200846/Z/16/Z), by the Gatsby Charitable Foundation (GAT3237), and by the Bettencourt-Schueller Foundation. J.F. was supported by the DFG (FE 1563/1-1). G.S.X.E.J. was funded by Medical Research Council. D.D.B. funded by HHMI. G.S.X.E.J., D.D.B., and S.W. were funded by a Wellcome Collaborative Award (203261/Z/16/Z)

    Studies of CTNNBL1 and FDFT1 variants and measures of obesity: analyses of quantitative traits and case-control studies in 18,014 Danes

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    <p>Abstract</p> <p>Background</p> <p>A genome-wide scan in unrelated US Caucasians identified rs7001819 upstream of farnesyl-diphosphate farnesyltransferase 1 (<it>FDFT1</it>) and multiple variants within catenin (cadherin-associated protein), β-like 1 (<it>CTNNBL1</it>) to associate strongly with body mass index (BMI). The most significantly associating variants within <it>CTNNBL1 </it>including rs6013029 and rs6020846 were additionally confirmed to associate with morbid obesity in a French Caucasian case-control sample. The aim of this study was to investigate the impact of these three variants on obesity, through analyses of obesity-related quantitative traits, and case-control studies in large study samples of Danes.</p> <p>Methods</p> <p>The <it>FDFT1 </it>rs7001819, <it>CTNNBL1 </it>rs6013029 and rs6020846 were genotyped, using TaqMan allelic discrimination, in a combined study sample comprising 18,014 participants ascertained from; the population-based Inter99 cohort (<it>n </it>= 6,514), the ADDITION Denmark screening study cohort (<it>n </it>= 8,662), and a population-based sample (<it>n </it>= 680) and a type 2 diabetic patients group (<it>n </it>= 2,158) from Steno Diabetes Center.</p> <p>Results</p> <p>Both <it>CTNNBL1 </it>variants associated with body weight and height with per allele effect sizes of 1.0 [0.3–0.8] kg and 0.6 [0.2–0.9] cm, respectively, for the rs6020846 G-allele. No association was observed with BMI and waist circumference. In case-control studies neither of the <it>CTNNBL1 </it>variants showed association with overweight, obesity or morbid obesity (rs6013029: Odds Ratio (OR)<sub>overweight </sub>= 1.02 [0.90–1.16], OR<sub>obesity </sub>= 1.09 [0.95–1.25], OR<sub>morbidobesity </sub>= 1.26 [0.91–1.74]; rs6020846: OR<sub>overweight </sub>= 1.05 [0.93–1.18], OR<sub>obesity</sub>= 1.13 [1.00–1.28], OR<sub>morbidobesity </sub>= 1.17 [0.86–1.61]). However, in meta-analyses of the present and the previous study, both the rs6013029 T-allele and the rs6020846 G-allele increased the risk of developing morbid obesity (rs6013029: OR<sub>combined </sub>= 1.36 [1.12–1.64], <it>p </it>= 0.002; rs6020846: OR<sub>combined </sub>= 1.26 [1.06–1.51], <it>p </it>= 0.01), and obesity (rs6013029: OR<sub>combined </sub>= 1.17 [1.04–1.31], <it>p </it>= 0.007; rs6020846: OR<sub>combined </sub>= 1.17 [1.05–1.30], <it>p </it>= 0.004).</p> <p>The <it>FDFT1 </it>rs7001819 C-allele showed no association with obesity-related quantitative measures or dichotomous measures of overweight, obesity and morbid obesity.</p> <p>Conclusion</p> <p><it>CTNNBL1 </it>variants associated with body weight and height, and confer the risk of developing obesity in meta-analyses combining the present and a previous study. <it>FDFT1 </it>rs7001819 showed no association with obesity, neither when analysing quantitative traits nor when performing case-control studies of obesity.</p

    Genetic evidence that raised sex hormone binding globulin (SHBG) levels reduce the risk of type 2 diabetes

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    Epidemiological studies consistently show that circulating sex hormone binding globulin (SHBG) levels are lower in type 2 diabetes patients than non-diabetic individuals, but the causal nature of this association is controversial. Genetic studies can help dissect causal directions of epidemiological associations because genotypes are much less likely to be confounded, biased or influenced by disease processes. Using this Mendelian randomization principle, we selected a common single nucleotide polymorphism (SNP) near the SHBG gene, rs1799941, that is strongly associated with SHBG levels. We used data from this SNP, or closely correlated SNPs, in 27 657 type 2 diabetes patients and 58 481 controls from 15 studies. We then used data from additional studies to estimate the difference in SHBG levels between type 2 diabetes patients and controls. The SHBG SNP rs1799941 was associated with type 2 diabetes [odds ratio (OR) 0.94, 95% CI: 0.91, 0.97; P = 2 × 10−5], with the SHBG raising allele associated with reduced risk of type 2 diabetes. This effect was very similar to that expected (OR 0.92, 95% CI: 0.88, 0.96), given the SHBG-SNP versus SHBG levels association (SHBG levels are 0.2 standard deviations higher per copy of the A allele) and the SHBG levels versus type 2 diabetes association (SHBG levels are 0.23 standard deviations lower in type 2 diabetic patients compared to controls). Results were very similar in men and women. There was no evidence that this variant is associated with diabetes-related intermediate traits, including several measures of insulin secretion and resistance. Our results, together with those from another recent genetic study, strengthen evidence that SHBG and sex hormones are involved in the aetiology of type 2 diabetes

    Altered Small-World Brain Networks in Schizophrenia Patients during Working Memory Performance

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    Impairment of working memory (WM) performance in schizophrenia patients (SZ) is well-established. Compared to healthy controls (HC), SZ patients show aberrant blood oxygen level dependent (BOLD) activations and disrupted functional connectivity during WM performance. In this study, we examined the small-world network metrics computed from functional magnetic resonance imaging (fMRI) data collected as 35 HC and 35 SZ performed a Sternberg Item Recognition Paradigm (SIRP) at three WM load levels. Functional connectivity networks were built by calculating the partial correlation on preprocessed time courses of BOLD signal between task-related brain regions of interest (ROIs) defined by group independent component analysis (ICA). The networks were then thresholded within the small-world regime, resulting in undirected binarized small-world networks at different working memory loads. Our results showed: 1) at the medium WM load level, the networks in SZ showed a lower clustering coefficient and less local efficiency compared with HC; 2) in SZ, most network measures altered significantly as the WM load level increased from low to medium and from medium to high, while the network metrics were relatively stable in HC at different WM loads; and 3) the altered structure at medium WM load in SZ was related to their performance during the task, with longer reaction time related to lower clustering coefficient and lower local efficiency. These findings suggest brain connectivity in patients with SZ was more diffuse and less strongly linked locally in functional network at intermediate level of WM when compared to HC. SZ show distinctly inefficient and variable network structures in response to WM load increase, comparing to stable highly clustered network topologies in HC
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