199 research outputs found

    Cafestol increases serum cholesterol levels in apolipoprotein E*3-Leiden transgenic mice by suppression of bile acid synthesis

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    Cafestol, a diterpene present in unfiltered coffee, potently increases serum cholesterol levels in humans. So far, no suitable animal model has been found to study the biochemical background of this effect. We determined the effect of cafestol on serum cholesterol and triglycerides in different mouse strains and subsequently studied its mechanism of action in apolipoprotein (apo) E*3-Leiden transgenic mice. ApoE*3-Leiden, heterozygous low density lipoprotein–receptor (LDLR /-) knockout, or wild-type (WT) C57BL/6 mice were fed a high- (0.05 t/wt) or a low- (0.01 t/wt) cafestol diet or a placebo diet for 8 weeks. Standardized to energy intake, these amounts are equal to 40, 8, or 0 cups of unfiltered coffee per 10 MJ per day in humans. In apoE*3-Leiden mice, serum cholesterol was statistically significantly increased by 33␘n the low- and by 61␘n the high-cafestol diet. In LDLR /- and WT mice, the increases were 20nd 24°respectively, on the low-cafestol diet and 55nd 46°respectively, on the high-cafestol diet. These increases were mainly due to a rise in very low density lipoprotein (VLDL) and intermediate density lipoprotein cholesterol in all 3 mouse strains. To investigate the mechanism of this effect, apoE*3-Leiden mice were fed a high-cafestol or a placebo diet for 3 weeks. Cafestol suppressed enzyme activity and mRNA levels of cholesterol 7-hydroxylase by 57nd 58°respectively. mRNA levels of enzymes involved in the alternate pathway of bile acid synthesis, ie, sterol 27-hydroxylase and oxysterol 7-hydroxylase, were reduced by 32nd 48°respectively. The total fecal bile acid output was decreased by 41ÐCafestol did not affect hepatic free and esterified cholesterol, but it decreased LDLR mRNA levels by 37ÐThe VLDL apoB and triglyceride production rates, as measured after Triton injection, were 2-fold decreased by cafestol, indicating that the number of particles secreted had declined and that there was no change in the amount of triglycerides present in the VLDL particle during cafestol treatment. However, the VLDL particles contained a 4-times higher amount of cholesteryl esters, resulting in a net 2-fold increased secretion of cholesteryl esters. The decrease in triglyceride production was the result of a reduction in hepatic triglyceride content by 52ÐIn conclusion, cafestol increases serum cholesterol levels in apoE*3-Leiden mice by suppression of the major regulatory enzymes in the bile acid synthesis pathways, leading to decreased LDLR mRNA levels and increased secretion of hepatic cholesterol esters. We suggest that suppression of bile acid synthesis may provide an explanation for the cholesterol-raising effect of cafestol in humans

    How does the electromagnetic field couple to gravity, in particular to metric, nonmetricity, torsion, and curvature?

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    The coupling of the electromagnetic field to gravity is an age-old problem. Presently, there is a resurgence of interest in it, mainly for two reasons: (i) Experimental investigations are under way with ever increasing precision, be it in the laboratory or by observing outer space. (ii) One desires to test out alternatives to Einstein's gravitational theory, in particular those of a gauge-theoretical nature, like Einstein-Cartan theory or metric-affine gravity. A clean discussion requires a reflection on the foundations of electrodynamics. If one bases electrodynamics on the conservation laws of electric charge and magnetic flux, one finds Maxwell's equations expressed in terms of the excitation H=(D,H) and the field strength F=(E,B) without any intervention of the metric or the linear connection of spacetime. In other words, there is still no coupling to gravity. Only the constitutive law H= functional(F) mediates such a coupling. We discuss the different ways of how metric, nonmetricity, torsion, and curvature can come into play here. Along the way, we touch on non-local laws (Mashhoon), non-linear ones (Born-Infeld, Heisenberg-Euler, Plebanski), linear ones, including the Abelian axion (Ni), and find a method for deriving the metric from linear electrodynamics (Toupin, Schoenberg). Finally, we discuss possible non-minimal coupling schemes.Comment: Latex2e, 26 pages. Contribution to "Testing Relativistic Gravity in Space: Gyroscopes, Clocks, Interferometers ...", Proceedings of the 220th Heraeus-Seminar, 22 - 27 August 1999 in Bad Honnef, C. Laemmerzahl et al. (eds.). Springer, Berlin (2000) to be published (Revised version uses Springer Latex macros; Sec. 6 substantially rewritten; appendices removed; the list of references updated

    Liever inleiden dan afwachten bij aterme zwangerschapshypertensie en milde preeclampsie: HYPITAT-studie

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    OBJECTIVE: To investigate what would benefit women with mild full-term pregnancy-related hypertension most: induction of labour or expectant monitoring, from the perspective of clinical effectiveness, maternal quality of life, and costs. DESIGN: Randomised clinical trial. Trial registration number ISRCTN08132825. METHODS: We undertook a multicentre randomised controlled trial in 38 hospitals in the Netherlands between October 2005 and March 2008. We enrolled patients with a singleton pregnancy in cephalic presentation at 36-41 weeks' gestation, who had gestational hypertension or mild preeclampsia. Participants were randomly allocated to receive either induction of labour or expectant monitoring. The primary outcome was a composite measure of poor maternal outcome, defined as maternal mortality, maternal morbidity (eclampsia, 'haemolysis, elevated liver enzymes, low platelets' (HELLP) syndrome, pulmonary oedema, thrombo-embolic disease and abruptio placentae), progression to severe hypertension or proteinuria, and major postpartum haemorrhage. Secondary outcomes were mode of delivery, neonatal outcome, maternal quality of life and costs. Analysis was by intention to treat. RESULTS: A total of 756 patients were allocated to receive induction of labour (n = 377 patients) or expectant monitoring (n = 379). No cases of maternal or neonatal death or eclampsia were recorded. Development of poor maternal outcome was significantly lower in the induction of labour group (117 women) than the expectant monitoring group (166 women) (31% versus 44%; relative risk 0.71 (95% CI: 0.59-0.86); p < 0.001). The caesarean section rate was lower among women in the induction of labour group (n = 54) compared to women in the expectant monitoring group (n = 72) (14% versus 19%; relative risk 0.75 (95% CI: 0.55-1.04)< p = 0.085). Neonatal outcomes and quality of life were comparable between both groups. Induction of labour is a cost saving strategy (difference euro 831). CONCLUSION: For women with full-term gestational hypertension and pre-eclampsia, induction of labour is associated with improved maternal outcome and lower costs, without the additional risk of a caesarean section being necessary

    The metabolic syndrome and risk of sudden cardiac death: The atherosclerosis risk in communities study

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    Background--Prior studies have demonstrated a link between the metabolic syndrome and increased risk of cardiovascular mortality. Whether the metabolic syndrome is associated with sudden cardiac death is uncertain. Methods and Results--We characterized the relationship between sudden cardiac death and metabolic syndrome status among participants of the ARIC (Atherosclerosis Risk in Communities) Study (1987-2012) free of prevalent coronary heart disease or heart failure. Among 13 168 participants, 357 (2.7%) sudden cardiac deaths occurred during a median follow-up of 23.6 years. Participants with the metabolic syndrome (n=4444) had a higher cumulative incidence of sudden cardiac death than those without it (n=8724) (4.1% versus 2.3%, P < 0.001). After adjustment for participant demographics and clinical factors other than components of the metabolic syndrome, the metabolic syndrome was independently associated with sudden cardiac death (hazard ratio, 1.70, 95% confidence interval, 1.37-2.12, P < 0.001). This relationship was not modified by sex (interaction P=0.10) or race (interaction P=0.62) and was mediated by the metabolic syndrome criteria components. The risk of sudden cardiac death varied according to the number of metabolic syndrome components (hazard ratio 1.31 per additional component of the metabolic syndrome, 95% confidence interval, 1.19-1.44, P < 0.001). Of the 5 components, elevated blood pressure, impaired fasting glucose, and low high-density lipoprotein were independently associated with sudden cardiac death. Conclusions--We observed that the metabolic syndrome was associated with a significantly increased risk of sudden cardiac death irrespective of sex or race. The risk of sudden cardiac death was proportional to the number of metabolic syndrome components

    One-loop corrections to omega photoproduction near threshold

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    One-loop corrections to ω\omega photoproduction near threshold have been investigated by using the approximation that all relevant transition amplitudes are calculated from the tree diagrams of effective Lagrangians. With the parameters constrained by the data of γNπN\gamma N \to \pi N, γNρN\gamma N \to \rho N, and πNωN\pi N \to \omega N reactions, it is found that the one-loop effects due to the intermediate πN\pi N and ρN\rho N states can significantly change the differential cross sections and spin observables. The results from this exploratory investigation suggest strongly that the coupled-channel effects should be taken into account in extracting reliable resonance parameters from the data of vector meson photoproduction in the resonance region.Comment: 19 pages, REVTeX, 14 figures, title changed, revised version to appear in Phys. Rev.
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