512 research outputs found

    Mephedrone in adolescent rats: residual memory impairment and acute but not lasting 5-HT depletion

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    Mephedrone (4-methylmethcathinone, MMC) is a popular recreational drug, yet its potential harms are yet to be fully established. The current study examined the impact of single or repeated MMC exposure on various neurochemical and behavioral measures in rats. In Experiment 1 male adolescent Wistar rats received single or repeated (once a day for 10 days) injections of MMC (30 mg/kg) or the comparator drug methamphetamine (METH, 2.5 mg/kg). Both MMC and METH caused robust hyperactivity in the 1 h following injection although this effect did not tend to sensitize with repeated treatment. Striatal dopamine (DA) levels were increased 1 h following either METH or MMC while striatal and hippocampal serotonin (5-HT) levels were decreased 1 h following MMC but not METH. MMC caused greater increases in 5-HT metabolism and greater reductions in DA metabolism in rats that had been previously exposed to MMC. Autoradiographic analysis showed no signs of neuroinflammation ([125I]CLINDE ligand used as a marker for translocator protein (TSPO) expression) with repeated exposure to either MMC or METH. In Experiment 2, rats received repeated MMC (7.5, 15 or 30 mg/kg once a day for 10 days) and were examined for residual behavioral effects following treatment. Repeated high (30 mg/kg) dose MMC produced impaired novel object recognition 5 weeks after drug treatment. However, no residual changes in 5-HT or DA tissue levels were observed at 7 weeks post-treatment. Overall these results show that MMC causes acute but not lasting changes in DA and 5-HT tissue concentrations. MMC can also cause long-term memory impairment. Future studies of cognitive function in MMC users are clearly warranted. © 2012 PLoS On

    Sternal plating for primary and secondary sternal closure; can it improve sternal stability?

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    <p>Abstract</p> <p>Background</p> <p>Sternal instability with mediastinitis is a very serious complication after median sternotomy. Biomechanical studies have suggested superiority of rigid plate fixation over wire cerclage for sternal fixation. This study tests the hypothesis that sternal closure stability can be improved by adding plate fixation in a human cadaver model.</p> <p>Methods</p> <p>Midline sternotomy was performed in 18 human cadavers. Four sternal closure techniques were tested: (1) approximation with six interrupted steel wires; (2) approximation with six interrupted cables; (3) closure 1 (wires) or 2 (cables) reinforced with a transverse sternal plate at the sixth rib; (4) Closure using 4 sternal plates alone. Intrathoracic pressure was increased in all techniques while sternal separation was measured by three pairs of sonomicrometry crystals fixed at the upper, middle and lower parts of the sternum until 2.0 mm separation was detected. Differences in displacement pressures were analyzed using repeated measures ANOVA and Regression Coefficients.</p> <p>Results</p> <p>Intrathoracic pressure required to cause 2.0 mm separation increased significantly from 183.3 ± 123.9 to 301.4 ± 204.5 in wires/cables alone vs. wires/cables plus one plate respectively, and to 355.0 ± 210.4 in the 4 plates group (p < 0.05). Regression Coefficients (95% CI) were 120 (47–194) and 142 (66–219) respectively for the plate groups.</p> <p>Conclusion</p> <p>Transverse sternal plating with 1 or 4 plates significantly improves sternal stability closure in human cadaver model. Adding a single sternal plate to primary closure improves the strength of sternal closure with traditional wiring potentially reducing the risk of sternal dehiscence and could be considered in high risk patients.</p

    Impact of Empiric Antimicrobial Therapy on Outcomes in Patients with Escherichia coli and Klebsiella pneumoniae Bacteremia: A Cohort Study

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    <p>Abstract</p> <p>Background</p> <p>It is unclear whether appropriate empiric antimicrobial therapy improves outcomes in patients with bacteremia due to <it>Escherichia coli </it>or <it>Klebsiella</it>. The objective of this study is to assess the impact of appropriate empiric antimicrobial therapy on in-hospital mortality and post-infection length of stay in patients with <it>Escherichia coli </it>or <it>Klebsiella </it>bacteremia while adjusting for important confounding variables.</p> <p>Methods</p> <p>We performed a retrospective cohort study of adult patients with a positive blood culture for <it>E. coli </it>or <it>Klebsiella </it>between January 1, 2001 and June 8, 2005 and compared in-hospital mortality and post-infection length of stay between subjects who received appropriate and inappropriate empiric antimicrobial therapy. Empiric therapy was defined as the receipt of an antimicrobial agent between 8 hours before and 24 hours after the index blood culture was drawn and was considered appropriate if it included antimicrobials to which the specific isolate displayed <it>in vitro </it>susceptibility. Data were collected electronically and through chart review. Survival analysis was used to statistically assess the association between empiric antimicrobial therapy and outcome (mortality or length of stay). Multivariable Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI).</p> <p>Results</p> <p>Among 416 episodes of bacteremia, 305 (73.3%) patients received appropriate empiric antimicrobial therapy. Seventy-one (17%) patients died before discharge from the hospital. The receipt of appropriate antimicrobial agents was more common in hospital survivors than in those who died (p = 0.04). After controlling for confounding variables, there was no association between the receipt of appropriate empiric antimicrobial therapy and in-hospital mortality (HR, 1.03; 95% CI, 0.60 to 1.78). The median post-infection length of stay was 7 days. The receipt of appropriate antimicrobial agents was not associated with shortened post-infection length of stay, even after controlling for confounding (HR, 1.11; 95% CI 0.86 to 1.44).</p> <p>Conclusion</p> <p>Appropriate empiric antimicrobial therapy for <it>E. coli </it>and <it>Klebsiella </it>bacteremia is not associated with lower in-hospital mortality or shortened post-infection length of stay. This suggests that the choice of empiric antimicrobial agents may not improve outcomes and also provides data to support a randomized trial to test the hypothesis that use (and overuse) of broad-spectrum antibiotics prior to the availability of culture results is not warranted.</p

    Fatigue testing of three peristernal median sternotomy closure techniques

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    Failure of a sternotomy closure because of closure system fatigue is a complication that may result in dehiscence and put the individual at risk for serious complications. The purpose of this study was to assess the fatigue performance of three peristernal median sternotomy closure techniques (figure-of-eight stainless-steel wires, figure-of-eight stainless-steel cables, or Pectofix Dynamic Sternal Fixation [DSF] stainless-steel plates) in order to quantify the potential risk of fatigue failure of these devices when subject to cyclic loads in physiologically relevant loading directions

    Designation processes and semantic substitutions used by european portuguese children in a vocabulary test

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    This research study focus on the designation processes and semantic substitutions of each word on the vocabulary sub-task from the language test for children – ABFW, standardized in Brazil and adapted to European Portuguese, as well as the comparison of the results obtained in the two countries, to analyze the relevance of their extensibility to the Portuguese population. Methods: The test was applied to 150 children from 5 to 6 years old, of typical development. The test consists of 9 conceptual categories. Each category consists of different words, which were always assessed in the same sequential order. Results: The sample of this study showed a lower performance only in clothes, places and food semantic categories. All the other categories have outperformed the standard. The categories of vocabulary with higher percentage in the right designation of the words were colors and shapes, animals and toys and music instruments. The categories with a higher percentage of substitution processes, from the reference results, were: food and locations. The most recurrent substitution processes were the co-hyponym, words that designate semantic attributes, valorization of the visual stimulus, hypernym and parasynonyms Conclusion: Given the homogeneity of the results of this study with the results obtained with other studies in Brazil, this test reveal potentiality as an instrument for vocabulary assessment in Portugal.Objetivo: Este estudo teve por objetivo a análise e quantificação dos processos de designação e substituição semântica apresentados na prova do vocabulário do Teste de Linguagem Infantil ABFW, padronizado no Brasil e adaptado para Português Europeu (PE), assim como a comparação dos resultados obtidos nos dois países, de forma a analisar a pertinência da sua extensibilidade à população portuguesa. Métodos: A prova foi aplicada a 150 crianças de 5 e 6 anos de idade, de desenvolvimento típico, na Região Norte de Portugal. A prova é constituída por nove categorias conceituais e cada categoria formada por diferentes vocábulos, que foram avaliados sempre pela mesma ordem sequencial. Resultados: A amostra mostrou desempenho inferior, em relação à norma, apenas nas categorias semânticas vestuário, locais e alimentos. Todas as outras categorias revelaram desempenho superior. As categorias do vocabulário que apresentaram maior percentagem de respostas corretas foram: animais, formas e cores e brinquedos e instrumentos musicais. As categorias que apresentaram percentagem superior de processos de substituição, em relação à norma, foram alimentos e locais. Os processos de substituição mais utilizados foram: substituição por co-hipônimo, vocábulos que designam atributos semânticos, valorização do estímulo visual, hiperônimos e parassinônimos. Conclusão: Dada a homogeneidade dos resultados deste estudo com os resultados obtidos em outros estudos no Brasil, esta prova revela potencialidades como instrumento de avaliação do vocabulário em Portugal.This work is funded by CIEd – Research Centre on Education, projects UID/CED/1661/2013 and UID/CED/1661/2016, Institute of Education, University of Minho, through national funds of FCT/MCTESPT.info:eu-repo/semantics/publishedVersio

    Schmallenberg virus pathogenesis, tropism and interaction with the innate immune system of the host

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    Schmallenberg virus (SBV) is an emerging orthobunyavirus of ruminants associated with outbreaks of congenital malformations in aborted and stillborn animals. Since its discovery in November 2011, SBV has spread very rapidly to many European countries. Here, we developed molecular and serological tools, and an experimental in vivo model as a platform to study SBV pathogenesis, tropism and virus-host cell interactions. Using a synthetic biology approach, we developed a reverse genetics system for the rapid rescue and genetic manipulation of SBV. We showed that SBV has a wide tropism in cell culture and “synthetic” SBV replicates in vitro as efficiently as wild type virus. We developed an experimental mouse model to study SBV infection and showed that this virus replicates abundantly in neurons where it causes cerebral malacia and vacuolation of the cerebral cortex. These virus-induced acute lesions are useful in understanding the progression from vacuolation to porencephaly and extensive tissue destruction, often observed in aborted lambs and calves in naturally occurring Schmallenberg cases. Indeed, we detected high levels of SBV antigens in the neurons of the gray matter of brain and spinal cord of naturally affected lambs and calves, suggesting that muscular hypoplasia observed in SBV-infected lambs is mostly secondary to central nervous system damage. Finally, we investigated the molecular determinants of SBV virulence. Interestingly, we found a biological SBV clone that after passage in cell culture displays increased virulence in mice. We also found that a SBV deletion mutant of the non-structural NSs protein (SBVΔNSs) is less virulent in mice than wild type SBV. Attenuation of SBV virulence depends on the inability of SBVΔNSs to block IFN synthesis in virus infected cells. In conclusion, this work provides a useful experimental framework to study the biology and pathogenesis of SBV

    Application of Inelastic Neutron Scattering to the Methanol-to-Gasoline Reaction Over a ZSM-5 Catalyst

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    Inelastic neutron scattering (INS) is used to investigate a ZSM-5 catalyst that has been exposed to methanol vapour at elevated temperature. In-line mass spectrometric analysis of the catalyst exit stream confirms methanol-to-gasoline chemistry, whilst ex situ INS measurements detect hydrocarbon species formed in/on the catalyst during methanol conversion. These preliminary studies demonstrate the capability of INS to complement infrared spectroscopic characterisation of the hydrocarbon pool present in/on ZSM-5 during the MTG reaction

    Assessing potential sources of clustering in individually randomised trials

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    Recent reviews have shown that while clustering is extremely common in individually randomised trials (for example, clustering within centre, therapist, or surgeon), it is rarely accounted for in the trial analysis. Our aim is to develop a general framework for assessing whether potential sources of clustering must be accounted for in the trial analysis to obtain valid type I error rates (non-ignorable clustering), with a particular focus on individually randomised trials

    Comparative effectiveness of manipulation, mobilisation and the Activator instrument in treatment of non-specific neck pain: a systematic review

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    BACKGROUND: Neck pain is a common problem and different forms of manual therapy are used in its treatment. The purpose of this systematic review was to critically appraise the literature that directly compared manipulation, mobilisation and the Activator instrument for non-specific neck pain. METHODS: Electronic databases (MEDLINE, MANTIS and CINAHL) were searched from their inception to October 2005 for all English language randomised clinical trials that directly compared manipulation, mobilisation and the Activator instrument. Inclusion and exclusion criteria were applied to select the studies and these studies were then evaluated using validated criteria. RESULTS: Five such studies were identified. The methodological quality was mostly poor. Findings from the studies were mixed and no one therapy was shown to be more effective than the others. CONCLUSION: Further high quality research has to be done before a recommendation can be made as to the most effective manual method for non-specific neck pain
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