Population-based studies suggest a reduced incidence of morbidity and mortality from coronary heart disease caused by moderate and regular consumption of red wine. Endothelial nitric oxide (NO) is a ...pivotal vasoprotective molecule. This study examines the influence of red wine polyphenols on the regulation of endothelial nitric oxide synthase (eNOS) expression and subsequent NO synthesis, focusing on the putative long-lasting antiatherosclerotic effects of red wine.
Treatment (20 hours) of human umbilical vein endothelial cells (HUVECs) and of the HUVEC-derived cell line EA.hy926 with a alcohol-free red wine polyphenol extract (RWPE) led to a concentration-dependent (100 to 600 microg/mL), significant increase in NO release (up to 3.0-fold/HUVEC and 2.0-fold/EA.hy926) as shown by use of the fluorescent probe DAF-2. This effect was corroborated by the 14CL-arginine/L-citrulline conversion assay in intact EA.hy926 cells. RWPE (20 hours, 100 to 600 microg/mL) also significantly increased eNOS protein levels up to 2.1-fold. Furthermore, we found an increased human eNOS promotor activity (up to 2-fold) in response to red wine polyphenols (18 hours, 100 to 600 microg/mL), as demonstrated by a luciferase reporter gene assay.
We provide conclusive data showing for the first time that a RWPE increases eNOS expression and subsequent endothelial NO release. Increased active eNOS levels may antagonize the development of endothelial dysfunction and atherosclerosis, a hypothesis that supports the view that red wine indeed may have long-term protective cardiovascular properties mediated by its polyphenols.
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Cardiovascular diseases are known as the major causes of death or disability in western countries. Decreased bioavailability of endothelial derived nitric oxide (NO) is recognized as an important ...promoter in cardiovascular disease.
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In vivo studies suggest that phytoestrogens, especially isoflavones from soy, enhance endothelium‐dependent vasoreactivity.
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We hypothesized that isoflavones may affect the expression of endothelial‐type nitric oxide synthase (eNOS) and thereby NO formation in vitro.
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Human EA.hy926 endothelial cells were treated with the soybean isoflavones biochanin A and formononetin and with their metabolites genistein and daidzein. eNOS promoter activity was examined by a luciferase reporter gene assay (20 h). Active eNOS was detected by quantifying conversion of L‐arginine to L‐citrulline and by measuring NO released from endothelial cells using the fluorescent probe DAF‐2 (20–96 h).
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eNOS promoter activity increased in response to isoflavone treatment (20 h). NO and L‐citrulline production by EA.hy926 cells rose up to 1.7‐fold of control levels after stimulation with genistein for 48–96 h. From these results, we conclude that the suggested positive effects of soy isoflavones on vascular reactivity may be indeed mediated via a long‐term effect on the eNOS system.
British Journal of Pharmacology (2005) 144, 394–399. doi:10.1038/sj.bjp.0706075
The BepiColombo Laser Altimeter Thomas, N.; Hussmann, H.; Spohn, T. ...
Space science reviews,
02/2021, Letnik:
217, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The BepiColombo Laser Altimeter (BELA) is the first European laser altimeter constructed for interplanetary flight. BELA uses a 50 mJ pulsed Nd:YAG laser operating at 10 Hz with a 20 cm aperture ...receiver to perform the ranging. The instrument also uses a digital approach for range detection and pulse analysis. The ranging accuracy is expected to be better than 2 metres and ∼20 cm in optimum conditions. With the given, only slightly elliptical, orbit, BELA should return a consistent data set for the most if not all of the planet. The instrument is required to function in an extreme environment with the thermal issues being particularly demanding. Novel solutions have been taken to resolve these issues. BELA is described in detail and its predicted performance outlined on the basis of pre-flight testing.
4,5-Diaminofluorescein (DAF-2) and its membrane-permeable derivate DAF-2 diacetate are fluorescent probes that have been developed to perform real-time biological detection of nitric oxide (NO). ...Their use for intracellular imaging, however, has recently been seriously questioned and data using DAF-2 for extracellular NO detection at low levels, as for example released from endothelial cells, are rare. Here we show that a reliable detection of low levels of NO in biological systems by DAF-2 is possible (a) by using low DAF-2 concentrations (0.1 μM) and (b) by subtracting the DAF-2 auto-fluorescence from the measured total fluorescence. The described method allows easy real-time detection of endothelial NO formation.
Here we describe in more depth the previously published application of the fluorescent probe 4,5-diaminofluorescein (DAF-2) in order to reliably measure low levels of nitric oxide (NO) as released ...from human endothelial cells in vitro. The used approach is based on the following considerations a) use low concentrations of DAF-2 (0.1 micro M) in order to reduce the contribution of DAF-2 auto-fluorescence to the measured total fluorescence, and b) subtract the DAF-2 auto-fluorescence from the measured total fluorescence. The advantage of this method is the reliable quantification of NO in a biological system in the nanomolar range once thoroughly validated. Here we focus in addition to the previous publication (Leikert et al., FEBS Lett 2001, 506:131-134) on aspects of validation procedures as well as limitations and pitfalls of this method.
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