542 research outputs found

    Design and Cloning of Short HairpinRNAs (shRNAs) into a Lentiviral Silencing Vector to Study the Function of Selected Proteins in Neuronal Apoptosis

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    Double-stranded RNA-mediated interference (RNAi) is a new simple and fast research tool for shutting 7 down genes and characterizes function of their respective proteins. Many strategies for design and delivery of 8 siRNA to target cells are available. Here, we describe the use of lentiviral short hairpin RNA (shRNA) RNA 9 silencing to identify the involvement of d-serine racemase (SR)- an enzyme that syntheses d-serine to modu- 10 late glutamate-N-methyl-d-aspartate receptor- in regulating rat cerebellar granule neurons (CGN) apoptosis. 11 Apoptosis is induced by serum and KCl withdrawal and is detected with fluorometric caspase 3 assay

    Characterization of virulence factors in the newly described <i>Salmonella enterica</i> serotype Keurmassar emerging in Senegal (sub-Saharan Africa)

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    From 2000 to 2001, nine strains of Salmonella enterica belonging to the new serotype Keurmassar have been isolated from human and poultry samples at the Senegalese National Salmonella and Shigella Reference Laboratory at the Pasteur Institute, in Dakar. All strains carried virulence factors including Salmonella Pathogenicity Islands (SPI)-1, -2, -3 and -5 encoded genes. Strains did not harbour virulence plasmid. Ribotyping analysis revealed a single clone identical to Salmonella Decatur isolated in Zimbabwe. These data suggest that strains are closely related, and may have been spread clonally. In this new serotype, insertion sequence IS200 is not present

    Part-time work and other occupational risk factors for suicide among working women in the Swiss National Cohort.

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    The aim of this study was to describe the factors associated with mortality by suicide among working women focusing on work-related factors. The study population consisted in all Swiss residents recorded in the 1990 and/or the 2000 compulsory national censuses and were linked to emigration and mortality registers. We selected all women aged 18-65 and at work at the official census dates. Following work-related variables were available: socio-economic status, weekly hours of work, the sector of activity and the job title coded according to the International Standard Classification of Occupations (ISCO). The risk of suicide was modelled using negative binomial regression. The cohort comprised 1,771,940 women and 2526 deaths by suicide corresponding to 24.9 million person-years. The most significant non-occupational predictors of suicide were age, period, civil status, religion, nationality and geographical regions. Adjusted on these factors, part-time work was associated with increased suicide rates. According to job codes, health and social activities, in particular care-worker had the highest suicide risks. Suicide among working women depended on work-related factors even taking into account other socio-demographic factors

    Effective boundary conditions for dense granular flows

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    We derive an effective boundary condition for granular flow taking into account the effect of the heterogeneity of the force network on sliding friction dynamics. This yields an intermediate boundary condition which lies in the limit between no-slip and Coulomb friction; two simple functions relating wall stress, velocity, and velocity variance are found from numerical simulations. Moreover, we show that this effective boundary condition corresponds to Navier slip condition when GDR MiDi's model is assumed to be valid, and that the slip length depends on the length scale that characterises the system, \emph{viz} the particle diameter.Comment: 4 pages, 5 figure

    Investigation of the Chirikov resonance overlap criteria for equatorial magnetosonic waves

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    Observations of equatorial magnetosonic waves made during the Cluster I nnerMagnetospheric Campaign clearly show discrete spectra consisting of emissions around harmonics of theproton gyrofrequency. Equatorial magnetosonic waves are important because of their ability to efficientlyscatter electrons in energy and pitch angle. This wave-particle interaction is numerically modeled throughthe use of diffusion coefficients, calculated based on a continuous spectrum such as that observed byspectrum analyzers. Using the Chirikov overlap resonance criterion, the calculation of the diffusioncoefficient will be assessed to determine whether they should be calculated based on the discrete spectralfeatures as opposed to a continuous spectrum. For the period studied, it is determined that the discretenature of the waves does fulfill the Chirikov overlap criterion and so the use of quasi-linear theory with theassumption of a continuous frequency spectrum is valid for the calculation of diffusion coefficients

    Reference ranges of oxidative stress biomarkers selected for non-invasive biological surveillance of nanotechnology workers: Study protocol and meta-analysis results for 8-OHdG in exhaled breath condensate

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    In the field of engineered nanomaterials (ENMs) and other airborne particulate exposure biomonitoring, circulating oxidative stress biomarkers appear promising. These biomarkers could be monitored in different biological matrices. Exhaled breath condensate (EBC) enables their measurements in the respiratory tract, without affecting airway function or creating inflammation. The 8-hydroxy-2-deoxyguanosine (8-OHdG) was found increased in the EBC of ENM-exposed workers. Our objectives were to assess the reference range of 8-OHdG in the EBC and to identify determinants of its inter- and intra-individual variability. The meta-analysis was stratified by analytical method (chemical versus immunochemical analysis) and resulted in a between-study variability over 99 % of the total variability. The between-study variability completely dominated the within-studies variability. By using a mixed model with study ID as a random effect rather than a meta-regression, only smoking was evidenced as a potential determinant of 8-OHdG inter-individual variability, and only when immunochemical analysis was used. To our knowledge, this is the first meta-analysis aimed at estimating reference values for 8-OHdG in the EBC. The estimated values should be considered preliminary, as they are based on a limited number of studies, mostly of moderate to low quality of evidence. Further research is necessary to standardize EBC sampling, storage and analytical methods. Such a standardization would enable a more accurate estimation of the reference ranges of the 8-OHdG and potentially other biomarkers measurable in the EBC, which are essential for a meaningful interpretation of the biomonitoring results

    Cognitive Functions and White Matter Tract Damage in Amyotrophic Lateral Sclerosis: A Diffusion Tensor Tractography Study

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    BACKGROUND AND PURPOSE: ALS is predominantly a disease of the motor system, but cognitive and behavioral symptoms also are observed. DT MR imaging is sensitive to microstructural changes occurring in WM tracts of patients with ALS. In this study, we investigated the association between cognitive functions and extramotor WM tract abnormalities in ALS patients. MATERIALS AND METHODS: DT MR imaging was obtained from 16 nondemented patients with ALS and 15 healthy controls. Patients with ALS underwent a neuropsychologic and behavioral evaluation. DT tractography was used to asses the integrity of the CST, corpus callosum, and the major long-range association tracts. The relationship between DT MR imaging metrics and cognitive functions was tested by using linear model analyses, adjusting for age and clinical disability. RESULTS: Eleven patients (69%) scored below the fifth percentile in at least 1 cognitive test, and 2 of them had a mild executive impairment. Performances at tests assessing attention and executive functions correlated with DT MR imaging metrics of the corpus callosum, CST, and long association WM tracts bilaterally, including the cingulum, inferior longitudinal, inferior fronto-occipital, and uncinate fasciculi. Verbal learning and memory test scores were associated with fornix DT MR imaging values, whereas visual-spatial abilities correlated with left uncinate fractional anisotropy. CONCLUSIONS: WM tract degeneration is associated with neuropsychologic deficits in patients with ALS. DT tractography holds promise to gain insight into the role of the brain WM network abnormalities in the development of cognitive impairment in patients with ALS

    the topography of brain microstructural damage in amyotrophic lateral sclerosis assessed using diffusion tensor mr imaging

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    BACKGROUND AND PURPOSE: ALS leads to macrostructural (ie, cortical atrophy and hyperintensities along the corticospinal tract) and microstructural (ie, gray matter intrinsic damage) central nervous system abnormalities. We used a multimodal voxelwise imaging approach to assess microstructural changes independent of macrostructural volume loss in patients with ALS compared with HCs. MATERIALS AND METHODS: Twenty-three patients with ALS and 14 HCs were studied. Conventional imaging and DTI were performed. Images were processed by using SPM5 to assess measures of gray and white matter atrophy as well as microstructural damage (ie, MD and FA). DTI alterations independent of volume loss were investigated. RESULTS: When we accounted for both gray and white matter atrophy, patients with ALS showed increased MD values in several gray and white matter areas mainly located in the orbitofrontal and frontotemporal regions bilaterally, in the right genu of the corpus callosum, and in the right posterior limb of the internal capsule. When we accounted for white matter volume loss, patients with ALS showed decreased FA along the corticospinal tract bilaterally and in the left inferior frontal lobe relative to HCs. The MD of the orbitofrontal regions bilaterally was associated significantly with disease duration. CONCLUSIONS: In patients with ALS, DTI detects microstructural changes independent of brain tissue loss. The affected regions included both motor and extramotor areas. The extent of ALS-related DTI abnormalities was greater than that disclosed by the volumetric analysis
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