Anesthesiology Posters - 2019

Anesthesiology Postershttps://scholarlycommons.libraryinfo.bhs.org/research_education/1000/thumbnail.jp

The effects of a synthetic curcuminoid analogue,2,6-bis-(4-hydroxyl-3-methoxybenzylidine)cyclohexanone on proinflammatorysignaling pathways and CLP-induced lethal sepsis in mice.

We previously showed that 2,6-bis-(4-hydroxyl-3-methoxybenzylidine)cyclohexanone (BHMC), suppressed the synthesis of various proinflammatory mediators. In this study we explain the mechanism of action of BHMC in lipopolysaccharide (LPS)-induced U937 monocytes and further show that BHMC prevents lethality of CLP-induced sepsis. BHMC showed dose-dependent inhibitory effects on p38, JNK and ERK 1/2 activity as determined by inhibition of phosphorylation of downstream transcription factors ATF-2, c-Jun and Elk-1 respectively. Inhibition of these transcription factors subsequently caused total abolishment of AP-1–DNA binding. BHMC inhibited p65 NF-κB nuclear translocation and DNA binding of p65 NF-κB only at the highest concentration used (12.5 μM) but failed to alter phosphorylation of JNK, ERK1/2 and STAT-1. Since the inhibition of p38 activity was more pronounced we evaluated the possibility that BHMC may bind to p38. Molecular docking experiments confirmed that BHMC fits well in the highly conserved hydrophobic pocket of p38 MAP kinase. We also show that BHMC was able to improve survival from lethal sepsis in a murine caecal-ligation and puncture (CLP) model

Effects of 3-(2-Hydroxyphenyl)-1-(5-methyl-furan-2-y-l) propenone (HMP) upon signalling pathways of lipopolysaccharide-induced iNOS synthesis in RAW 264.7 cells.

NO synthesis in the RAW 264.7 murine macrophage line. The inhibition of NO synthesis was related to inhibition of p38 phosphorylation and kinase activity that led to significant inhibition of phosphorylation of ATF-2. This effect in turn caused inhibition of AP-1-DNA binding which partially explains the inhibitory effect upon the synthesis of iNOS. HMP had no effect upon phosphorylation of JNK, ERK1/2 and STAT-1. Kinase activity of JNK and ERK1/2 was also not affected by HMP as determined by levels of phosphorylated c-jun and phosphorylated elk-1. Furthermore HMP failed to block phosphorylation of IκBα, and subsequent nuclear translocation and DNA-binding activity of p65 NF-κB in IFN-γ/LPS-induced RAW 264.7 cells. Molecular docking experiments confirmed that HMP fits well in the highly conserved hydrophobic pocket of p38 MAP kinase. We conclude that the synthetic HMP is a chalcone analogue that selectively inhibits the p38/ATF-2 and AP-1 signaling pathways in the NO synthesis by the macrophage RAW 264.7

Oseltamivir resistance during treatment of influenza A (H5N1) infection

Influenza A (H5N1) virus with an amino acid substitution in neuraminidase conferring high-level resistance to oseltamivir was isolated from two of eight Vietnamese patients during oseltamivir treatment. Both patients died of influenza A (H5N1) virus infection, despite early initiation of treatment in one patient. Surviving patients had rapid declines in the viral load to undetectable levels during treatment. These observations suggest that resistance can emerge during the currently recommended regimen of oseltamivir therapy and may be associated with clinical deterioration and that the strategy for the treatment of influenza A (H5N1) virus infection should include additional antiviral agents. Copyright © 2005 Massachusetts Medical Society.published_or_final_versio

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ABSTRACT. Objective. To investigate whether development of systemic lupus erythematosus (SLE), its clinical manifestations, and autoantibody production are associated with polymorphisms of the mannose-binding lectin Conclusion. A significantly increased prevalence of anti-Smith antibody was associated with the heterozygous genotypes A/B and A/C. Although MBL structural gene polymorphism was not a risk factor for SLE development in this study population, homozygosity of MBL variant alleles may be a weak disease-modifying factor, particularly for renal involvement, in North American patients with SLE

Atrovirinone inhibits proinflammatory mediator synthesis through disruption of NF-kappaB nuclear translocation and MAPK phosphorylation in the murine monocytic macrophage RAW 264.7.

In a previous communication we showed that atrovirinone, a 1,4-benzoquinone isolated from the roots of Garcinia atroviridis, was able to inhibit several major proinflammatory mediators of inflammation. In this report we show that atrovirinone inhibits NO and PGE2 synthesis through inhibition of iNOS and COX-2 expression. We also show that atrovirinone inhibits the secretion of IL-1β and IL-6 in a dose dependent fashion whereas the secretion of IL-10, the anti-inflammatory cytokine, was enhanced. Subsequently we determined that the inhibition of proinflammatory cytokine synthesis and inducible enzyme expression was due to a dose-dependent inhibition of phosphorylation of p38 and ERK1/2. We also showed that atrovirinone prevented phosphorylation of I-κBα, which resulted in a reduction of p65NF-κB nuclear translocation as demonstrated by expression analysis. We conclude that atrovirinone is a potential anti-inflammatory drug lead that targets both the MAPK and NF-κB pathway

LAT is essential for the mast cell stabilising effect of tHGA in IgE-mediated mast cell activation

Mast cells play a central role in the pathogenesis of allergic reaction. Activation of mast cells by antigens is strictly dependent on the influx of extracellular calcium that involves a complex interaction between signalling molecules located within the cells. We have previously reported that tHGA, an active compound originally isolated from a local shrub known as Melicope ptelefolia, prevented IgE-mediated mast cell activation and passive systemic anaphylaxis by suppressing the release of interleukin-4 (IL-4) and tumour necrosis factor (TNF)-α from activated rat basophilic leukaemia (RBL)-2H3 cells. However, the mechanism of action (MOA) as well as the molecular target underlying the mast cell stabilising effect of tHGA has not been previously investigated. In this study, DNP-IgE-sensitised RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA. To dissect the MOA of tHGA in IgE-mediated mast cell activation, the effect of tHGA on the transcription of IL-4 and TNF-α mRNA was determined using Real Time-Polymerase Chain Reaction (qPCR) followed by Calcium Influx Assay to confirm the involvement of calcium in the activation of mast cells. The protein lysates were analysed by using Western Blot to determine the effect of tHGA on various important signalling molecules in the LAT-PLCγ-MAPK and PI3K-NFκB pathways. In order to identify the molecular target of tHGA in IgE-mediated mast cell activation, the LAT and LAT2 genes in RBL-2H3 cells were knocked-down by using RNA interference to establish a LAT/LAT2 competition model. The results showed that tHGA inhibited the transcription of IL-4 and TNF-α as a result of the suppression of calcium influx in activated RBL-2H3 cells. The results from Western Blot revealed that tHGA primarily inhibited the LAT-PLCγ-MAPK pathway with partial inhibition on the PI3K-p65 pathway without affecting Syk. The results from RNAi further demonstrated that tHGA failed to inhibit the release of mediators associated with mast cell degranulation under the LAT/LAT2 competition model in the absence of LAT. Collectively, this study concluded that the molecular target of tHGA could be LAT and may provide a basis for the development of a mast cell stabiliser which targets LAT

Anti-allergic activity of 2,4,6-trihydroxy-3-geranylacetophenone (tHGA) via attenuation of IgE-mediated mast cell activation and inhibition of passive systemic anaphylaxis

tHGA, a geranyl acetophenone compound originally isolated from a local shrub called Melicope ptelefolia, has been previously reported to prevent ovalbumin-induced allergic airway inflammation in a murine model of allergic asthma by targeting cysteinyl leukotriene synthesis. Mast cells are immune effector cells involved in the pathogenesis of allergic diseases including asthma by releasing cysteinyl leukotrienes. The anti-asthmatic properties of tHGA could be attributed to its inhibitory effect on mast cell degranulation. As mast cell degranulation is an important event in allergic responses, this study aimed to investigate the anti-allergic effects of tHGA in cellular and animal models of IgE-mediated mast cell degranulation. For in vitro model of IgE-mediated mast cell degranulation, DNP-IgE-sensitized RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA to induce degranulation. For IgE-mediated passive systemic anaphylaxis, Sprague Dawley rats were sensitized by intraperitoneal injection of DNP-IgE before challenged with DNP-BSA. Both in vitro and in vivo models showed that tHGA significantly inhibited the release of preformed mediators (β-hexosaminidase and histamine) as well as de novo mediators (interleukin-4, tumour necrosis factor-α, prostaglandin D2 and leukotriene C4). Pre-treatment of tHGA also prevented IgE-challenged RBL-2H3 cells and peritoneal mast cells from undergoing morphological changes associated with mast cell degranulation. These findings indicate that tHGA possesses potent anti-allergic activity via attenuation of IgE-mediated mast cell degranulation and inhibition of IgE-mediated passive systemic anaphylaxis. Thus, tHGA may have the potential to be developed as a mast cell stabilizer for the treatment of allergic diseases in the future

Tragedy of the Anticommons(ToA)in Agricultural Land Partition involving Fragmented Co-proprietorships: An Analysis of Malaysian Case Laws

There is a lack of understanding of the theory of the Tragedy of the Anticommons (ToA), a type of coordination breakdown or a hold-out problem involving multiple fragmented co -proprietorships with undivided shares, in the land partition context. This paper, hence, discusses how ToA occurs particularly in the agricultural land partition that is primarily governed under the National Land Code 1965 and proposes potential legal and non-legal approaches and mechanisms to address the land tragedy. An abductive content analysis of (9) case laws extracted from the LexisNexis database was performed through which themes and codes were developed to explain how ToA hindering land partition takes place. Subsequently, judicial decisions in solving disputes arising from land partition and existing best practices in dealing with the tragedy were reviewed. The case laws review indicated that unsuccessful agricultural land partition associated with high transaction costs in securing co-proprietors consensus is a form of simultaneous ToA, that most of the unpartitioned land (anticommons) may be subject to underinvestment (land mismanagement) and disuse. Key factors leading to disagreement among co-proprietors and consequently ToA are as follows: (i) unequal (unfair) proportion or shares of land; (ii) uneven geographical partition and spatial distribution of government reserves; and (iii) potential damages and negative effects (e.g., loss of income and property). To address ToA, these are legal mechanisms proposed: statutory enforcement of the National Land Code (NLC) 1965 (via land forfeiture and reversion), the Land Acquisition Act (LAA) 1960 on compulsory land acquisition, and judicial decisions (e.g., land partitions may take place if it is fairly distributed and made by the majority shareholders), while non-legal approaches cover negotiation and arbitration; en-bloc sales (partition); collective action through enhanced social capital; and imposition of a tax on underutilised land. By showcasing various agricultural anticommons tragedies and their potential negative externalities in the land partition context, this paper offers policy and management insights that help land officers and local authorities ensure the maximum efficiency and productivity (i.e., highest and best use) of the land