22 research outputs found

    Specific immune modulation of experimental colitis drives enteric alpha-synuclein accumulation and triggers age-related Parkinson-like brain pathology

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    Background: In some people with Parkinson’s disease (PD), a-synuclein (αSyn) accumulation may begin in the enteric nervous system (ENS) decades before development of brain pathology and disease diagnosis. Objective: To determine how different types and severity of intestinal inflammation could trigger αSyn accumulation in the ENS and the subsequent development of αSyn brain pathology. Methods: We assessed the effects of modulating short- and long-term experimental colitis on αSyn accumulation in the gut of αSyn transgenic and wild type mice by immunostaining and gene expression analysis. To determine the long-term effect on the brain, we induced dextran sulfate sodium (DSS) colitis in young αSyn transgenic mice and aged them under normal conditions up to 9 or 21 months before tissue analyses. Results: A single strong or sustained mild DSS colitis triggered αSyn accumulation in the submucosal plexus of wild type and αSyn transgenic mice, while short-term mild DSS colitis or inflammation induced by lipopolysaccharide did not have such an effect. Genetic and pharmacological modulation of macrophage-associated pathways modulated the severity of enteric αSyn. Remarkably, experimental colitis at three months of age exacerbated the accumulation of aggregated phospho-Serine 129 αSyn in the midbrain (including the substantia nigra), in 21- but not 9-month-old αSyn transgenic mice. This increase in midbrain αSyn accumulation is accompanied by the loss of tyrosine hydroxylase-immunoreactive nigral neurons. Conclusions: Our data suggest that specific types and severity of intestinal inflammation, mediated by monocyte/macrophage signaling, could play a critical role in the initiation and progression of PD

    Diffuse groundwater pollution by atmospheric deposition of organic compounds and heavy metals - experiences from SW Germany

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    At many places all over the world groundwater has become contaminated, mostly as a result of poorly designed hazardous waste disposal facilities, leakage fiom Underground storage tanks and mine tailings, and accidental spills. Groundwater pollution can also be caused by application of fertilizers and pesticides in agriculture. The chemicals trapped in the subsurface constitute a major long-term contamination source to a groundwater system, resulting in threat to groundwater supply and direct risk to human health, for example by volatilization of toxic compounds. Once a groundwater system becomes contarninated it is almost an impossible task to clean it up. Many contarninants are persistent and remain hazardous even at low concentrations. This publication comprises the proceedings of the International Conference on Groundwater Quality: Remediation and Protection (GQ'98) held at TĂĽbingen, Germany, in September 1998. As at the two previous conferences in the series, GQM'~(h~el d in Estonia in 1993) and ~4'95~ (held in Czech Republic in 1995), the major objectives of the GQ'98 Conference were to provide an international forum for state-of-the-art presentations on relevant methodologies and techniques, and to identiS, the needs for future developments. The conference focused on practical approaches to assess groundwater quality, viable solutions to contamination problems, and methods for protection. Also addressed were directly applicable methods for cornrnon field problems. Of particular interest were: - identification of processes and parameters limiting clean up efficiency; - methods to assess and monitor groundwater quality at field scale; - reactive transport/modelling in heterogeneous environrnents; - innovative remediation techniques

    Accumulation of polycyclic aromatic hydrocarbons in rural soils based on mass balances at the catchment scale

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    Polycyclic aromatic hydrocarbons (PAHs) are hydrophobic organic pollutants that are ubiquitously distributed in the environment at relatively high concentrations. In our study we investigated the long-term fate of atmospheric PAHs in soils of rural areas, resulting from diffuse pollution based on mass balances at the catchment scale. By determining PAHs in several environmental compartments, estimates of soil storages and water fluxes were made and compared with atmospheric deposition. The results indicate that more than 90% of the incoming PAHs remain in the catchments and accumulate in the topsoils. Furthermore, revolatilization of PAHs from soils and degradation in the soils is very limited, resulting in ongoing accumulation in topsoils, in particular for low-volatile PAHs. Combustion-derived carbonaceous particles were detected in atmospheric deposition as well as in the soil samples. Since these particles are very strong adsorbents, they are suspected to play a key role in the environmental fate of the diffuse distributed PAHs

    Quantification of biodegradation for o-xylene and naphthalene using first order decay models, Michaelis-Menten kinetics and stable carbon isotopes

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    At a former wood preservation plant severely contaminated with coal tar oil, in situ bulk attenuation and biodegradation rate constants for several monoaromatic (BTEX) and polyaromatic hydrocarbons (PAH) were determined using (1) classical first order decay models, (2) Michaelis-Menten degradation kinetics (MM), and (3) stable carbon isotopes, for o-xylene and naphthalene. The first order bulk attenuation rate constant for o-xylene was calculated to be 0.0025 d(-1) and a novel stable isotope-based first order model, which also accounted for the respective redox conditions, resulted in a slightly smaller biodegradation rate constant of 0.0019 d(-1). Based on MM-kinetics, the o-xylene concentration decreased with a maximum rate of k(max)=0.1 mu g/L/d. The bulk attenuation rate constant of naphthalene retrieved from the classical first order decay model was 0.0038 d(-1). The stable isotope-based biodegradation rate constant of 0.0027 d(-1) was smaller in the reduced zone, while residual naphthalene in the oxic part of the plume further downgradient was degraded at a higher rate of 0.0038 d(-1). With MM-kinetics a maximum degradation rate of k(max)=12 mu g/L/d was determined. Although best fits were obtained by MM-kinetics, we consider the carbon stable isotope-based approach more appropriate as it is specific for biodegradation (not overall attenuation) and at the same time accounts for the dominant electron-accepting process. For o-xylene a field based isotope enrichment factor epsilon(field) of - 1.4 could be determined using the Rayleigh model, which closely matched values from laboratory studies of o-xylene degradation under sulfate-reducing conditions. (C) 2008 Elsevier B.V. All rights reserved

    Carbohydrate based anti-bacterials

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    A method of inhibiting bacterial growth by contacting a bacteria with at least one disaccharide compound of General Formula (I)

    Disaccarides for drug discovery

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    Methods are described for the preparation of combinatorial libraries of potentially biologically active disaccharide compounds. These compounds are variously functionalized, with a view to varying lipid solubility size, function and other properties, with the particular aim of discovering novel drug or drug-like compounds, or compounds with useful properties. The invention provides intermediates, processes and synthetic strategies for the solution or solid phase synthesis of disaccharides, variously functionalised about the sugar ring, including the addition of aromaticity and charge, and the placement of pharmaceutically useful groups and isosteres

    A versatile synthetic approach toward diversity libraries using monosaccharide scaffolds

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    The pyranose scaffold is unique in its ability to position pharmacophore substituents in various ways in 3D space, and unique pharmacophore scanning libraries could be envisaged that focus on scanning topography rather than diversity in the type Of substituents. Approaches have been described that make use of amine and acid functionalities on the pyranose scaffolds to append substituents, and this has enabled the generation of libraries of significant structural diversity. Our general aim was to generate libraries of pyranose-based drug-like mimetics, where the substituents are held close to the scaffold, in order to obtain molecules with better defined positions for the pharmacophore substituents. Here we describe the development of a versatile synthetic route toward peptide mimetics build oil 2-amino pyranose scaffolds. The method allows introduction of a wide range of substituent types, it is regio- and stereospecific, and the later diversity steps are performed on solid phase. Further, the same process was applied oil glucose mid allose scaffolds, in the exemplified cases, and is likely adaptable to other pyranose building blocks. The methods developed in this work give access to molecules that position the three selected binding elements in various 3D orientations oil a pyranose scaffold and have been applied for the production of a systematically diverse library of several hundred monosaccharide-based mimetics
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