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Selected AbstractsSpatio-temporal point process filtering methods with an applicationENVIRONMETRICS, Issue 3-4 2010ena Frcalová Abstract The paper deals with point processes in space and time and the problem of filtering. Real data monitoring the spiking activity of a place cell of hippocampus of a rat moving in an environment are evaluated. Two approaches to the modelling and methodology are discussed. The first one (known from literature) is based on recursive equations which enable to describe an adaptive system. Sequential Monte Carlo methods including particle filter algorithm are available for the solution. The second approach makes use of a continuous time shot-noise Cox point process model. The inference of the driving intensity leads to a nonlinear filtering problem. Parametric models support the solution by means of the Bayesian Markov chain Monte Carlo methods, moreover the Cox model enables to detect adaptivness. Model selection is discussed, numerical results are presented and interpreted. Copyright © 2009 John Wiley & Sons, Ltd. [source] Vasoactive intestinal peptide induces regulatory T cells during experimental autoimmune encephalomyelitisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2006Amelia Fernandez-Martin Abstract CD4+CD25+ regulatory T cells (Treg) control the immune response to a variety of antigens, including self-antigens. Several models support the idea of the peripheral generation of CD4+CD25+ Treg from CD4+CD25, T cells. Little is known about the endogenous factors and mechanisms controlling the peripheral expansion of CD4+CD25+ Treg. In this study we report on the capacity of the vasoactive intestinal peptide (VIP), an immunosuppressive neuropeptide, to induce functional Treg in vivo during the development of experimental autoimmune encephalomyelitis (EAE), a multiple sclerosis model. The administration of VIP to EAE mice results in the expansion of the CD4+CD25+, Foxp3-expressing T cells in the periphery and the nervous system, which inhibit encephalitogenic T cell activation. In addition to the increase in the number of CD4+CD25+ Treg, VIP induces more efficient suppressors on a per cell basis. The VIP-generated CD4+CD25+ Treg transfer suppression and significantly ameliorate the progression of the disease. [source] Selenium and selenoproteins in the brain and brain diseasesJOURNAL OF NEUROCHEMISTRY, Issue 1 2003Jun Chen Abstract Over the past three decades, selenium has been intensively investigated as an antioxidant trace element. It is widely distributed throughout the body, but is particularly well maintained in the brain, even upon prolonged dietary selenium deficiency. Changes in selenium concentration in blood and brain have been reported in Alzheimer's disease and brain tumors. The functions of selenium are believed to be carried out by selenoproteins, in which selenium is specifically incorporated as the amino acid, selenocysteine. Several selenoproteins are expressed in brain, but many questions remain about their roles in neuronal function. Glutathione peroxidase has been localized in glial cells, and its expression is increased surrounding the damaged area in Parkinson's disease and occlusive cerebrovascular disease, consistent with its protective role against oxidative damage. Selenoprotein P has been reported to possess antioxidant activities and the ability to promote neuronal cell survival. Recent studies in cell culture and gene knockout models support a function for selenoprotein P in delivery of selenium to the brain. mRNAs for other selenoproteins, including selenoprotein W, thioredoxin reductases, 15-kDa selenoprotein and type 2 iodothyronine deiodinase, are also detected in the brain. Future research directions will surely unravel the important functions of this class of proteins in the brain. [source] The role of the Badger (Meles meles) in rabies epizootiology and the implications for Great BritainMAMMAL REVIEW, Issue 1 2002G. C. Smith ABSTRACT The occurrence of a wildlife rabies epizootic in Britain remains a very unlikely event, but it is important to examine all the possible consequences of such an event. Here, I examine the possible role of the European Badger (Meles meles) in such an epizootic. The population density of Badgers in Britain is much higher than that in Europe, and appears to have increased substantially over the last decade or so. The population parameters and epizootiology of rabies in the Badger are reviewed in comparison with the Fox (Vulpes vulpes) and other species. Mustelids appear to be very susceptible to rabies, with the smaller mustelids becoming aggressive, although Badgers do not appear to show heightened aggression when infected. Badger populations on the continent become severely reduced when rabies arrives in the area, and circumstantial evidence strongly suggests that Badgers can easily transmit the virus. Preliminary models support the idea that the Badger could be a very significant secondary host, especially in the initial rabies outbreak. The population recovery rate of the Badger suggests that it is unlikely to become a primary host, although short-term epizootics in the Badger population are likely. The potential for controlling rabies in the Badger is also examined. [source] Phylogeography and genetic structure of northern populations of the yellow warbler (Dendroica petechia)MOLECULAR ECOLOGY, Issue 6 2000Emmanuel Milot Abstract Phylogeographic patterns of intraspecific variation can provide insights into the population-level processes responsible for speciation and yield information useful for conservation purposes. To examine phylogeography and population structure in a migratory passerine bird at both continental and regional geographical scales, we analysed 344 bp of mitochondrial DNA (mtDNA) control region sequence from 155 yellow warblers (Dendroica petechia) collected from seven locations across Canada and from Alaska. There is a major subdivision between eastern (Manitoba to Newfoundland) and western (Alaska and British Columbia) populations which appears to have developed during the recent Pleistocene. Some localities within these two regions also differ significantly in their genetic composition, suggesting further subdivision on a regional geographical scale. Eastern and western birds form distinct phylogeographic entities and the clustering of all western haplotypes with two eastern haplotypes suggests that the western haplotypes may be derived from an eastern lineage. Analyses based on coalescent models support this explanation for the origin of western haplotypes. These results are consistent with important features of Mengel's model of warbler diversification. From a conservation perspective they also suggest that individual populations of migrant birds may form demographically isolated management units on a smaller scale than previously appreciated. [source] Octapeptide repeat insertions increase the rate of protease-resistant prion protein formationPROTEIN SCIENCE, Issue 3 2006Roger A. Moore PrP, prion protein; HaPrP, hamster prion protein; TSE, transmissible spongiform encephalopathies Abstract A central feature of transmissible spongiform encephalopathies (TSE or prion diseases) involves the conversion of a normal, protease-sensitive glycoprotein termed prion protein (PrP-sen) into a pro-tease-resistant form, termed PrP-res. The N terminus of PrP-sen has five copies of a repeating eight amino acid sequence (octapeptide repeat). The presence of one to nine extra copies of this motif is associated with a heritable form of Creutzfeld-Jakob disease (CJD) in humans. An increasing number of octapeptide repeats correlates with earlier CJD onset, suggesting that the rate at which PrP-sen misfolds into PrP-res may be influenced by these mutations. In order to determine if octapeptide repeat insertions influence the rate at which PrP-res is formed, we used a hamster PrP amyloid-forming peptide (residues 23,144) into which two to 10 extra octapeptide repeats were inserted. The spontaneous formation of protease-resistant PrP amyloid from these peptides was more rapid in response to an increased number of octapeptide repeats. Furthermore, experiments using full-length glycosylated hamster PrP-sen demonstrated that PrP-res formation also occurred more rapidly from PrP-sen molecules expressing 10 extra copies of the octapeptide repeat. The rate increase for PrP-res formation did not appear to be due to any influence of the octapeptide repeat region on PrP structure, but rather to more rapid binding between PrP molecules. Our data from both models support the hypothesis that extra octapeptide repeats in PrP increase the rate at which protease resistant PrP is formed which in turn may affect the rate of disease onset in familial forms of CJD. [source] Correlates of Collective Efficacy in the Italian Air ForceAPPLIED PSYCHOLOGY, Issue 3 2010Laura Borgogni Military technicians (N= 202) of the Telecommunication Maintenance Unit (TMU), as well as military staff (N= 185) in the Italian Air Force (IAF), were administered a questionnaire measuring self- and collective efficacy, perceptions of context (colleagues, direct superior, and top management), organisational commitment, and job satisfaction. Structural equation models support the hypothesised relationship among variables. Self-efficacy and perceptions of context were related to collective efficacy which in turn was related to organisational commitment and job satisfaction. Collective efficacy was explained by self-efficacy and by perceptions of context. In addition, organisational commitment was explained by collective efficacy, more so than job satisfaction. Perceptions of colleagues, direct superior, and top management were mainly related to job satisfaction. 202 techniciens militaires de l'Unité de Maintenance des Télécommunications ainsi que 185 militaires des Forces Aériennes Italiennes ont rempli un questionnaire portant sur l'efficience personnelle et collective, la perception de l'environnement (les collègues, le supérieur immédiat et le haut de la hiérarchie), l'implication organisationnelle et la satisfaction professionnelle. Des modèles en équations structurales ont confirmé les relations supposées entre les variables. L'efficience personnelle et la perception de l'environnement étaient liées à l'efficience collective qui était elle-même en relation avec l'implication organisationnelle et la satisfaction professionnelle. L'efficience collective procédait de l'efficience personnelle et de la perception de l'environnement. En outre, l'implication organisationnelle dépendait de l'efficience collective, plus que de la satisfaction professionnelle. La perception des collègues, du supérieur immédiat et du haut de la hiérarchie étaient principalement en rapport avec la satisfaction professionnelle. [source] Self-Assembly of a Triangle-Shaped, Hexaplatinum-Incorporated, Supramolecular Amphiphile in Solution and at InterfacesCHEMISTRY - A EUROPEAN JOURNAL, Issue 34 2009Umamageswaran Maran Dr. Abstract The self-assembly and characterization of a novel supramolecular amphiphile built from a new 60° amphiphilic precursor that incorporates hydrophilic platinum(II) metals and hydrophobic dioctadecyloxy chains is reported. The amphiphilic macrocycle and its precursor compound have been characterized by multinuclear NMR spectroscopy, ESI-MS, and other standard techniques. The coacervate morphology of the amphiphile at the liquid,liquid interface has been studied by using confocal optical microscopy and in situ Raman spectroscopy. The self-assembly of the amphiphilic macrocycle at the air,water interface has been investigated through Langmuir-trough techniques. The study indicates the possible formation of surface micelle-like aggregates. The disparity between the experimental molecular areas and those derived from molecular models support the idea of aggregation. AFM images of the surface aggregates show the formation of a flat topology with arbitrary ridgelike patterns. Reasonable molecular-packing arrangements are proposed to explain the molecular organization within the observed structures. [source] Immune function in hypopituitarism: time to reconsider?CLINICAL ENDOCRINOLOGY, Issue 4 2010Annice Mukherjee Summary Hypopituitarism is not currently considered as a potential cause of immune disruption in humans. Accumulating data from in vitro and animal models support a role for the pituitary gland in immune regulation. Furthermore, the increased mortality risk noted in patients with adult hypopituitarism remains poorly explained and immune dysfunction could conceivably contribute to this observation. In a recent issue of Clinical & Experimental Immunology, we presented new data relating to immune status in adults with treated, severe hypopituitarism. We observed humoral immune deficiency in a significant proportion, despite stable pituitary replacement, including growth hormone (GH). This was especially evident in those with low pretreatment IGF-I levels and appeared independent of anticonvulsant use or corticosteroid replacement. These observations require substantiation with future studies. In this short review, we summarize existing data relating to the effects of pituitary hormones on immune function and discuss potential clinical implications surrounding the hypothesis of immune dysregulation in severe hypopituitarism. [source] | ||||||||||||||||