908 research outputs found

    Plasma anandamide and other N-acylethanolamines are correlated with their corresponding free fatty acid levels under both fasting and non-fasting conditions in women

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    N-acylethanolamines (NAEs), such as anandamide (AEA), are a group of endogenous lipids derived from a fatty acid linked to ethanolamine and have a wide range of biological activities, including regulation of metabolism and food intake. We hypothesized that i) NAE plasma levels are associated with levels of total free fatty acids (FFAs) and their precursor fatty acid in fasting and non-fasting conditions and ii) moderate alcohol consumption alters non-fasting NAE levels. In a fasting and non-fasting study we sampled blood for measurements of specific NAEs and FFAs. In the fasting study blood was drawn after an overnight fast in 22 postmenopausal women. In the non-fasting study blood was sampled before and frequently after a standardized lunch with beer or alcohol-free beer in 19 premenopausal women. Fasting AEA levels correlated with total FFAs (r = 0.84; p <0.001) and arachidonic acid levels (r = 0.42; p <0.05). Similar results were observed for other NAEs with both total FFAs and their corresponding fatty acid precursors. In addition, AEA (r = 0.66; p <0.01) and OEA levels (r = 0.49;

    Reducing the Dimensionality of Linear Quadratic Control Problems

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    In linear-quadratic control (LQC) problems with singular control cost matrix and/or singular transition matrix, we derive a reduction of the dimension of the Riccati matrix, simplifying iteration and solution. Employing a novel transformation, we show that, under a certain rank condition, the matrix of optimal feedback coefficients is linear in the reduced Riccati matrix. For a substantive class of problems, our technique permits scalar iteration, leading to simple analytical solution. By duality the technique can also be applied to Kalman filtering problems with a singular measurement error covariance matrix

    Government expenditures and equilibrium real exchange rates

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    Economists have long investigated theoretically and empirically the relationship between government spending and equilibrium real exchange rates. As Frenkel and Razin (1996) summarize for a small open economy, government expenditures (financed by lump-sum taxes) influence real exchange rates via a resource-withdrawal channel and a consumption-tilting channel. Recent theoretical and empirical studies, such as Froot and Rogoff (1991), Rogoff (1992), De Gregorio, Giovannini, and Krueger (1994), De Gregorio, Giovannini, and Wolf (1994), De Gregorio and Wolf (1994), and Chinn and Johnston (1996), have focused only upon the effects of government spending through the resource-withdrawal channel. Extending Frenkel and Razin (1996), this paper generates closed-form theoretical solutions for the relationships among the real exchange rate, relative per capita private consumption, relative per capita government consumption, and relative per capita tradables and nontradables production in a two-country general equilibrium model. Using relative price level, private and government per capita consumption, and relative productivity data from the Summers and Heston (1991) Penn World Tables and OECD (1 996) data for a sample of OECD countries relative to the United States, we estimate the model\u27 s structural equations. The results suggest that government expenditures influence equilibrium real exchange rates approximately equally via the resource-withdrawal and consumption-tilting channels. Moreover, the results imply that government spending and private consumption are complements in utility

    The ethanolamide metabolite of DHA, docosahexaenoylethanolamine, shows immunomodulating effects in mouse peritoneal and RAW264.7 macrophages: evidence for a new link between fish oil and inflammation

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    Several mechanisms have been proposed for the positive health effects associated with dietary consumption of long-chain n-3 PUFA (n-3 LC-PUFA) including DHA (22 : 6n-3) and EPA (20 : 5n-3). After dietary intake, LC-PUFA are incorporated into membranes and can be converted to their corresponding N-acylethanolamines (NAE). However, little is known on the biological role of these metabolites. In the present study, we tested a series of unsaturated NAE on the lipopolysaccharide (LPS)-induced NO production in RAW264.7 macrophages. Among the compounds tested, docosahexaenoylethanolamine (DHEA), the ethanolamide of DHA, was found to be the most potent inhibitor, inducing a dose-dependent inhibition of NO release. Immune-modulating properties of DHEA were further studied in the same cell line, demonstrating that DHEA significantly suppressed the production of monocyte chemotactic protein-1 (MCP-1), a cytokine playing a pivotal role in chronic inflammation. In LPS-stimulated mouse peritoneal macrophages, DHEA also reduced MCP-1 and NO production. Furthermore, inhibition was also found to take place at a transcriptional level, as gene expression of MCP-1 and inducible NO synthase was inhibited by DHEA. To summarise, in the present study, we showed that DHEA, a DHA-derived NAE metabolite, modulates inflammation by reducing MCP-1 and NO production and expression. These results provide new leads in molecular mechanisms by which DHA can modulate inflammatory processes

    What do financial markets reveal about global warming? Working paper series--09-13

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    Global warming and its importance are controversial. While a variety of estimates exists of the likelihood of global warming and its economic cost, financial market information can provide an objective assessment of expected losses due to global warming. We consider a Merton-type asset pricing model in which asset prices are affected by the changes in investment opportunities caused by global warming. In this setting, global warming would imply a negative risk premium, with most assets loading negatively on the global warming factor, and financial assets in sectors that are more sensitive to global warming exhibiting stronger negative loadings. Utilizing a variant of Campbell and Diebold's (2005) weather forecasting model in conjunction with Lamont's (2001) and Vassalou's (2003) approach for extracting financial market "news", we empirically uncover the global warming factor. We find that the risk premium is indeed significantly negative and becoming more so over time, that loadings for most assets are negative, and that asset portfolios in industries considered to be more vulnerable to global warming (see IPCC, 2007, and Quiggin and Horowitz, 2003) have significantly stronger negative loadings on the global warming factor. We estimate that required returns on average are 0.11 percentage points higher due to the global warming factor, translating to a present value loss of 4.18 percent of wealth. The industry loadings appear to be unrelated to potential vulnerability to emissions regulation. Rather, the loss in wealth represents a general cost from increased systematic risk due to uncertainty in the extent and impact of warming and the increased incidence of extreme weather events, thus complementing existing estimates of the cost of global warming

    Dietary Crude Lecithin Increases Systemic Availability of Dietary Docosahexaenoic Acid with Combined Intake in Rats

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    Crude lecithin, a mixture of mainly phospholipids, potentially helps to increase the systemic availability of dietary omega-3 polyunsaturated fatty acids (n-3 PUFA), such as docosahexaenoic acid (DHA). Nevertheless, no clear data exist on the effects of prolonged combined dietary supplementation of DHA and lecithin on RBC and plasma PUFA levels. In the current experiments, levels of DHA and choline, two dietary ingredients that enhance neuronal membrane formation and function, were determined in plasma and red blood cells (RBC) from rats after dietary supplementation of DHA-containing oils with and without concomitant dietary supplementation of crude lecithin for 2–3 weeks. The aim was to provide experimental evidence for the hypothesized additive effects of dietary lecithin (not containing any DHA) on top of dietary DHA on PUFA levels in plasma and RBC. Dietary supplementation of DHA-containing oils, either as vegetable algae oil or as fish oil, increased DHA, eicosapentaenoic acid (EPA), and total n-3 PUFA, and decreased total omega-6 PUFA levels in plasma and RBC, while dietary lecithin supplementation alone did not affect these levels. However, combined dietary supplementation of DHA and lecithin increased the changes induced by DHA supplementation alone. Animals receiving a lecithin-containing diet also had a higher plasma free choline concentration as compared to controls. In conclusion, dietary DHA-containing oils and crude lecithin have synergistic effects on increasing plasma and RBC n-3 PUFA levels, including DHA and EPA. By increasing the systemic availability of dietary DHA, dietary lecithin may increase the efficacy of DHA supplementation when their intake is combined.Nutricia Researc

    ABT-888 enhances cytotoxic effects of temozolomide independent of MGMT status in serum free cultured glioma cells

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    Background: The current standard of care for Glioblastoma Multiforme (GBM) consists of fractionated focal irradiation with concomitant temozolomide (TMZ) chemotherapy. A promising strategy to increase the efficacy of TMZ is through interference with the DNA damage repair machinery, by poly(ADP-ribose) polymerase protein inhibition(PARPi). The o

    A Systematic Comparison Identifies an ATP-Based Viability Assay as Most Suitable Read-Out for Drug Screening in Glioma Stem-Like Cells

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    Serum-free culture methods for patient-derived primary glioma cultures, selecting for glioma stem-like cells (GSCs), are becoming the gold standard in neurooncology research. These GSCs can be implemented in drug screens to detect patient-specific responses, potentially bridging the translational gap to personalized medicine. Since numerous compounds are available, a rapid and reliable readout for drug efficacies is required. This can be done using approaches that measure viability, confluency, cytotoxicity, or apoptosis. To determine which assay is best suitable for drug screening, 10 different assays were systematically tested on established glioma cell lines and validated on a panel of GSCs. General applicability was assessed using distinct treatment modalities, being temozolomide, radiation, rapamycin, and the oncolytic adenovirus Delta24-RGD. The apoptosis and cytotoxicity assays did not unequivocally detect responses and were excluded from further testing. The NADH- and ATP-based viability assays revealed comparable readout for all treatments; however, the latter had smaller standard deviations and direct readout. Importantly, drugs that interfere with cell metabolism require alternative techniques such as confluency monitoring to accurately measure treatment effects. Taken together, our data suggest that the combination of ATP luminescence assays with confluency monitoring provides the most specific and reproducible readout for drug screening on primary GSCs
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