38 research outputs found

    First order parent formulation for generic gauge field theories

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    We show how a generic gauge field theory described by a BRST differential can systematically be reformulated as a first order parent system whose spacetime part is determined by the de Rham differential. In the spirit of Vasiliev's unfolded approach, this is done by extending the original space of fields so as to include their derivatives as new independent fields together with associated form fields. Through the inclusion of the antifield dependent part of the BRST differential, the parent formulation can be used both for on and off-shell formulations. For diffeomorphism invariant models, the parent formulation can be reformulated as an AKSZ-type sigma model. Several examples, such as the relativistic particle, parametrized theories, Yang-Mills theory, general relativity and the two dimensional sigma model are worked out in details.Comment: 36 pages, additional sections and minor correction

    Parent formulation at the Lagrangian level

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    The recently proposed first-order parent formalism at the level of equations of motion is specialized to the case of Lagrangian systems. It is shown that for diffeomorphism-invariant theories the parent formulation takes the form of an AKSZ-type sigma model. The proposed formulation can be also seen as a Lagrangian version of the BV-BRST extension of the Vasiliev unfolded approach. We also discuss its possible interpretation as a multidimensional generalization of the Hamiltonian BFV--BRST formalism. The general construction is illustrated by examples of (parametrized) mechanics, relativistic particle, Yang--Mills theory, and gravity.Comment: 26 pages, discussion of the truncation extended, typos corrected, references adde

    Reduction of microglial activity in a model of multiple sclerosis by dipyridamole

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    BACKGROUND: Despite extensive and persistent activation of microglia in multiple sclerosis (MS), microglia inhibitors have not yet been identified for treatment of the disorder. We sought to identify medications already in clinical use that could inhibit the activation of microglia. On the basis of the reported inhibitory effects of dipyridamole on phosphodiesterase activity that result in the production of various anti-inflammatory outcomes, we selected it for study. Dipyridamole is used clinically for secondary prevention in stroke. In this study, dipyridamole was examined using microglia in culture and in the mouse model of MS, experimental autoimmune encephalomyelitis (EAE). RESULTS: We found that dipyridamole attenuated the elevation of several cytokines and chemokines in human microglia caused by Toll-like receptor stimulation. Morphological characteristics of activated microglia in culture were also normalized by dipyridamole. In mice, dipyridamole decreased the clinical severity of EAE and reduced microglial activity and other histological indices of EAE in the spinal cord. CONCLUSIONS: Dipyridamole is an inhibitor of microglia activation and may have a role in MS and other neurological conditions to attenuate microglial activity

    Evidence for a Modulatory Role of Ih on the Firing of a Subgroup of Midbrain Dopamine Neurons

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    A previous investigation has suggested that the hyperpolarization-activated cation current Ih does not contribute to the spontaneous firing of midbrain dopaminergic neurons. This conclusion was reached using Cs(-1). We have re-examined this question with extracellular recordings in slices using the more specific blocker ZD7288. In two-thirds of the cells, low concentrations of ZD7288 induced a decrease of the spontaneous firing. The maximal inhibition was about 40% and the mean IC50 was 1.6 microM. This effect was probably direct because it persisted in the presence of antagonists of various receptors. These concentrations of ZD7288 had no effect in the remaining one third of the examined cells. However, the highest concentration of ZD7288 (300 microM) abolished the firing of all dopaminergic neurons, probably by a mechanism unrelated to the blockade of Ih. We conclude that Ih controls to a certain extent the firing of a majority of midbrain dopaminergic neurons

    Paravertebral Burkitt's Lymphoma in a Child: An Unusual Presentation

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    Paravertebral malignant tumors constitute 4.8% of cancer cases in pediatric oncology and are mostly composed of neuroblastoma (46.4%) and soft tissue sarcomas (35.7%). We describe the case of a Caucasian 6-year-old boy who was admitted for middle back pain radiated to limbs and progressively increasing weakness of the legs, suggesting a spinal cord disease. The exploration revealed two paravertebral masses extending through the neural foraminae into the epidural space. The association with elevated serum neuron specific enolase suggested at first the diagnosis of neuroblastoma, but the pathological examination revealed a Burkitt's lymphoma. This is a rare location of sporadic Burkitt's lymphoma with neurologic syndrome as first symptoms

    Sickle cell disease from Africa to Belgium, from neonatal screening to clinical management.

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    To describe the severity of sickle cell disease (SCD) in newborns in Belgium and evaluate the impact of neonatal screening (NS) on clinical outcome.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe
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