2,085 research outputs found

    Lipopolysaccharide and toll-like receptor 4 in dogs with congenital portosystemic shunts

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    Surgical attenuation of a congenital portosystemic shunt (CPSS) results in increased portal vein perfusion, liver growth and clinical improvement. Portal lipopolysaccharide (LPS) is implicated in liver regeneration via toll-like receptor (TLR) 4 mediated cytokine activation. The aim of this study was to investigate factors associated with LPS in dogs with CPSS. Plasma LPS concentrations were measured in the peripheral and portal blood using a limulus amoebocyte lysate (LAL) assay. LPS concentration was significantly greater in the portal blood compared to peripheral blood in dogs with CPSS (P = 0.046) and control dogs (P = 0.002). LPS concentrations in the peripheral (P = 0.012) and portal (P = 0.005) blood of dogs with CPSS were significantly greater than those of control dogs. The relative mRNA expression of cytokines and TLRs was measured in liver biopsies from dogs with CPSS using quantitative PCR. TLR4 expression significantly increased following partial CPSS attenuation (P = 0.020). TLR4 expression was significantly greater in dogs that tolerated complete CPSS attenuation (P = 0.011) and those with good portal blood flow on pre-attenuation (P = 0.004) and post-attenuation (P = 0.015) portovenography. Serum interleukin (IL)-6 concentration was measured using a canine specific ELISA and significantly increased 24 h following CPSS attenuation (P < 0.001). Portal LPS was increased in dogs with CPSS, consistent with decreased hepatic clearance. TLR4 mRNA expression was significantly associated with portal blood flow and increased following surgery. These findings support the concept that portal LPS delivery is important in the hepatic response to surgical attenuation. Serum IL-6 significantly increased following surgery, consistent with LPS stimulation via TLR4, although this increase might be non-specific

    A web-based application for assessing jurisdictional geospatial readiness

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    Jurisdictions along the Gulf Coast are threatened by hurricanes. The effects of hurricanes are devastating, and the response and recovery efforts are crucial for saving lives and property. Geospatial technologies have been implemented in the response and recovery phases. However, the potential of geospatial technologies were not utilized due to data and capability issues. This study was implemented to design and develop a tool that would help a jurisdiction determine if it can apply geospatial technologies effectively in the response and recovery phases. This tool enables a jurisdiction to complete an assessment regarding GIS data, hardware, software, and personnel capabilities. Assessment results are scored using a weighted linear model, and scores are shown to the user. A rules-based system was built to show the jurisdiction methods for improving its score to the optimum level. This tool enables jurisdictions to diagnose geospatial readiness and make modifications that enhance response and recovery

    A web-based application for assessing jurisdictional geospatial readiness

    Get PDF
    Jurisdictions along the Gulf Coast are threatened by hurricanes. The effects of hurricanes are devastating, and the response and recovery efforts are crucial for saving lives and property. Geospatial technologies have been implemented in the response and recovery phases. However, the potential of geospatial technologies were not utilized due to data and capability issues. This study was implemented to design and develop a tool that would help a jurisdiction determine if it can apply geospatial technologies effectively in the response and recovery phases. This tool enables a jurisdiction to complete an assessment regarding GIS data, hardware, software, and personnel capabilities. Assessment results are scored using a weighted linear model, and scores are shown to the user. A rules-based system was built to show the jurisdiction methods for improving its score to the optimum level. This tool enables jurisdictions to diagnose geospatial readiness and make modifications that enhance response and recovery

    Using small molecules to facilitate exchange of bicarbonate and chloride anions across liposomal membranes

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    Bicarbonate is involved in a wide range of biological processes, which include respiration, regulation of intracellular pH and fertilization. In this study we use a combination of NMR spectroscopy and ion-selective electrode techniques to show that the natural product prodigiosin, a tripyrrolic molecule produced by microorganisms such as Streptomyces and Serratia, facilitates chloride/bicarbonate exchange (antiport) across liposomal membranes. Higher concentrations of simple synthetic molecules based on a 4,6-dihydroxyisophthalamide core are also shown to facilitate this antiport process. Although it is well known that proteins regulate Cl-/HCO3- exchange in cells, these results suggest that small molecules may also be able to regulate the concentration of these anions in biological systems

    Dynamic p-enrichment schemes for multicomponent reactive flows

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    We present a family of p-enrichment schemes. These schemes may be separated into two basic classes: the first, called \emph{fixed tolerance schemes}, rely on setting global scalar tolerances on the local regularity of the solution, and the second, called \emph{dioristic schemes}, rely on time-evolving bounds on the local variation in the solution. Each class of pp-enrichment scheme is further divided into two basic types. The first type (the Type I schemes) enrich along lines of maximal variation, striving to enhance stable solutions in "areas of highest interest." The second type (the Type II schemes) enrich along lines of maximal regularity in order to maximize the stability of the enrichment process. Each of these schemes are tested over a pair of model problems arising in coastal hydrology. The first is a contaminant transport model, which addresses a declinature problem for a contaminant plume with respect to a bay inlet setting. The second is a multicomponent chemically reactive flow model of estuary eutrophication arising in the Gulf of Mexico.Comment: 29 pages, 7 figures, 3 table
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