1,504 research outputs found

    Ontogeny of synaptophysin and synaptoporin in the central nervous system

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    The expression of the synaptic vesicle antigens synaptophysin (SY) and synaptoporin (SO) was studied in the rat striatum, which contains a nearly homogeneous population of GABAergic neurons. In situ hybridization revealed high levels of SY transcripts in the striatal anlage from embryonic day (E) 14 until birth. In contrast. SO hybridization signals were low, and no immunoreactive cell bodies were detected at these stages of development. At E 14, SY-immunoreactivity was restricted to perikarya. In later prenatal stages of development SY-immunoreactivity appeared in puncta (identified as terminals containing immunostained synaptic vesicles), fibers, thick fiber bundles and ‘patches’. In postnatal and adult animals, perikarya of striatal neurons exhibited immunoreaction for SO; ultrastructurally SO antigen was found in the Golgi apparatus and in multivesicular bodies. SO-positive boutons were rare in the striatum. In the neuropil, numerous presynaptic terminals positive for SY were observed. Our data indicate that the expression of synaptic vesicle proteins in GABAergic neurons of the striatum is developmentally regulated. Whereas SY is prevalent during embryonic development, SO is the major synaptic vesicle antigen expressed postnatally by striatal neurons which project to the globus pallidus and the substantia nigra. In contrast synapses of striatal afferents (predominantly from cortex, thalamus and substantia nigra) contain SY

    Petroleum basins of South America

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    Tumour burden in early stage Hodgkin's disease: the single most important prognostic factor for outcome after radiotherapy.

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    One hundred and forty-two patients with Hodgkin's disease PS I or II were treated with total or subtotal nodal irradiation as part of a prospective randomized trial in the Danish National Hodgkin Study during the period 1971-83. They were followed till death or--at the time of this analysis--from 15 to 146 months after initiation of therapy. The initial tumour burden of each patient was assessed, combining tumour size of each involved region and number of regions involved. Tumour burden thus assessed proved to be the single most important prognostic factor with regard to disease free survival. Other known prognostic factors such as number of involved regions, mediastinal size, pathological stage, systemic symptoms, and ESR were related to tumour burden and lost their prognostic significance in a multivariate analysis. The only other factors of independent significance were histologic subtype and, to a lesser extent, sex. Combining tumour burden and histologic subtype made it possible to single out a group of patients with a very poor disease free survival. These patients also had a poorer survival from Hodgkin's disease and thus clearly candidates for additional initial treatment

    Detecting structural variances of Co_3O_4 catalysts by controlling beam-induced sample alterations in the vacuum of a transmission electron microscope

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    This article summarizes core aspects of beam-sample interactions in research that aims at exploiting the ability to detect single atoms at atomic resolution by mid-voltage transmission electron microscopy. Investigating the atomic structure of catalytic Co_3O_4 nanocrystals underscores how indispensable it is to rigorously control electron dose rates and total doses to understand native material properties on this scale. We apply in-line holography with variable dose rates to achieve this goal. Genuine object structures can be maintained if dose rates below ~100 e/Å^2s are used and the contrast required for detection of single atoms is generated by capturing large image series. Threshold doses for the detection of single atoms are estimated. An increase of electron dose rates and total doses to common values for high resolution imaging of solids stimulates object excitations that restructure surfaces, interfaces, and defects and cause grain reorientation or growth. We observe a variety of previously unknown atom configurations in surface proximity of the Co_3O_4 spinel structure. These are hidden behind broadened diffraction patterns in reciprocal space but become visible in real space by solving the phase problem. An exposure of the Co_3O_4 spinel structure to water vapor or other gases induces drastic structure alterations that can be captured in this manner

    Development of ultra-light pixelated ladders for an ILC vertex detector

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    The development of ultra-light pixelated ladders is motivated by the requirements of the ILD vertex detector at ILC. This paper summarizes three projects related to system integration. The PLUME project tackles the issue of assembling double-sided ladders. The SERWIETE project deals with a more innovative concept and consists in making single-sided unsupported ladders embedded in an extra thin plastic enveloppe. AIDA, the last project, aims at building a framework reproducing the experimental running conditions where sets of ladders could be tested

    Congenital Prosopagnosia: Multistage Anatomical and Functional Deficits in Face Processing Circuitry

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    Face recognition is a primary social skill which depends on a distributed neural network. A pronounced face recognition deficit in the absence of any lesion is seen in congenital prosopagnosia. This study investigating 24 congenital prosopagnosic subjects and 25 control subjects aims at elucidating its neural basis with fMRI and voxel-based morphometry. We found a comprehensive behavioral pattern, an impairment in visual recognition for faces and buildings that spared long-term memory for faces with negative valence. Anatomical analysis revealed diminished gray matter density in the bilateral lingual gyrus, the right middle temporal gyrus, and the dorsolateral prefrontal cortex. In most of these areas, gray matter density correlated with memory success. Decreased functional activation was found in the left fusiform gyrus, a crucial area for face processing, and in the dorsolateral prefrontal cortex, whereas activation of the medial prefrontal cortex was enhanced. Hence, our data lend strength to the hypothesis that congenital prosopagnosia is explained by network dysfunction and suggest that anatomic curtailing of visual processing in the lingual gyrus plays a substantial role. The dysfunctional circuitry further encompasses the fusiform gyrus and the dorsolateral prefrontal cortex, which may contribute to their difficulties in long-term memory for complex visual information. Despite their deficits in face identity recognition, processing of emotion related information is preserved and possibly mediated by the medial prefrontal cortex. Congenital prosopagnosia may, therefore, be a blueprint of differential curtailing in networks of visual cognition

    The human parasite Loa loa in cytokine and cytokine receptor gene knock out BALB/c mice: survival, development and localization

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    <p>Abstract</p> <p>Background</p> <p>Immunological mechanisms involved in the survival and development of human filarial species in the vertebrate host are poorly known due to the lack of suitable experimental models. In order to understand the role of cytokines in the survival and development of filarial larvae in the vertebrate host, we infected different strains of BALB/c mice deficient in a number of cytokine or cytokine receptor genes with <it>Loa loa</it>. The survival and development of larvae were monitored.</p> <p>Methods</p> <p>BALB/c mice genetically deficient in IL-4R, IFN-γ, IFN-γ/IL-5, IL-5, and IL-4R/IL-5 cytokine or cytokine receptor genes were infected with a human strain of <it>L. loa </it>and necropsies were performed at different time intervals up to 70 days post infection to monitor the survival and development of <it>L. loa </it>larvae. The larvae were teased out of the skin, muscles, peritoneal and pleural cavities, heart and lung tissues. The length and width of the recovered larvae were measured to assess their growth.</p> <p>Results</p> <p>In mice deficient for IL-4R, IFN-γ, IFN-γ/IL-5, IL-5 and IL-4R/IL-5, the larvae survived up to 5, 20, 40, 50 and 70 days respectively. Worms recovered 70 days post infection in IL-4R/IL-5 DKO mice were young adults and measured 10.12 mm in length and 0.1 mm in width. Overall, 47% of larvae were recovered from subcutaneous tissues, 40% from muscles, 6% from the peritoneal cavity and 4% from the pleural cavity, lungs and heart.</p> <p>Conclusion</p> <p><it>L. loa </it>exhibits a differential survival and development in different strains of cytokine or cytokine receptor gene knockout mice with IL-4R and IL-5 playing critical roles in the host resistance to <it>L. loa </it>infection. The knock out BALB/c mouse therefore represents a useful tool to explore the key effectors of adaptive immunity involved in the killing of the <it>L. loa </it>parasite in a mammal host.</p

    Adaptações de metodologia para criação de Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

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    Helicoverpa armigera (Hübner) destaca-se entre os principais lepidópteros desfolhadores de culturas brasileiras nas duas últimas safras. Visando aprimorar as técnicas de criação de H. armigera em laboratório, foi avaliada uma metodologia de criação no Laboratório de Resistência de Plantas a Insetos e Plantas Inseticidas (LARESPI) da FCA/UNESP, Botucatu. Para criação, os adultos identificados quanto ao sexo e separados em casais são mantidos em gaiolas (tubos de PVC, 20 cm de diâmetro e 30 cm de altura). A face superior das gaiolas são vedadas com tecido voil, permitindo aeração e alimentação dos adultos. A face inferior é apoiada em prato de plástico (28 cm de diâmetro) recoberto com papel filtro. Internamente as gaiolas são forradas com papel kraft natural servindo de substrato para oviposição. Sobre o voil é acondicionada uma porção de algodão umedecido em solução de mel a 10%, e outra contendo apenas água. As lagartas são obtidas a partir das posturas colhidas diariamente no papel kraft e no tecido voil. As posturas são transferidas inicialmente para um recipiente plástico transparente de 500 mL, contendo aproximadamente 50g de dieta artificial. A partir do terceiro instar, é feita a transferência individual das lagartas para recipientes de 50 mL, contendo aproximadamente 5g de dieta artificial. Estes recipientes são vedados com tampas, e as lagartas são mantidas em seu interior até formação das pupas. As pupas são coletadas e acondicionadas em recipientes de acrílico transparente (11,5 x 11,5 x 3,5 cm) contendo vermiculita umedecida, permanecendo nesse ambiente até a emergência dos adultos. A criação é mantida sob temperatura de 25ºC, umidade relativa de 70±10% e fotofase de 12h. A iluminação natural é mantida por lâmpadas dos tipos fluorescente ?super luz do dia? (20W) e fluorescente ?plant light? (grolux F 20 W T12), nas prateleiras de criação. Para averiguação de temperatura e umidade relativa do ar utiliza-se o termohigrômetro digital. Para validação da criação descrita realizaram-se diversos experimentos preliminares. A metodologia apresentada possibilita a criação de H. armigera em diferentes escalas, permitindo a realização de ensaios diversos
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