Xu J.-J.,Peking University |
Xu J.-J.,Laboratory of Physicochemical Research |
Wang S.-Y.,Peking University |
Chen Y.,Peking University |
And 6 more authors.
Acta Pharmacologica Sinica
Aim:Dopamine receptors are present in the nervous system and also widely distributed in the periphery. The aim of this study was to investigate the role of D 1 subtype dopamine receptors (DRD 1) in the regulation of dehydroepiandrosterone sulfotransferase (SULT2A1) in HepG2 cells.Methods:HepG2 cells were treated with DRD 1 agonists with or without DRD 1 antagonist for 9 d. DRD 1 and SULT2A1 mRNA expression, protein expression, and SULT2A1 activity were detected using RT-PCR, Western blotting and HPLC, respectively. The level of cAMP was measured using a commercial kit.Results:All the 5 DR subtypes (DRD 1 -DRD 5) were found to be expressed in HepG2 cells. Treatment of HepG2 cells with the specific DRD 1 agonists SKF82958 (2.5 μmol/L) or SKF38393 (5 and 50 μmol/L) significantly increased the mRNA and protein expression of both DRD 1 and SULT2A1, and increased SULT2A1 activity and cAMP levels. These effects were partially blocked by co-treatment with the specific DRD 1 antagonist SCH23390 (2.5 μmol/L). In addition, transfection of HepG2 cells with DRD 1 -specific siRNAs decreased DRD 1 mRNA expression by 40%, which resulted in the reduction of SULT2A1 mRNA expression by 60%, protein expression by 40%, and enzyme activity by 20%.Conclusion:DRD 1 activation upregulates DRD 1 and SULT2A1 expression and SULT2A1 activity in HepG2 cells, suggesting that the DRD 1 subtype may be involved in the metabolism of drugs and xenobiotics through regulating SULT2A1. © 2014 CPS and SIMM. Source
Huang B.,Laboratory of Physicochemical Research |
Wang Z.,China National Institute for Nutrition and Food Safety |
Yao J.,U.S. Center for Disease Control and Prevention |
Ke X.,Zhejiang University of Technology |
And 5 more authors.
A method has been developed for quantitative analysis of vitamin K1 in vegetables and fruits by LC-MS/MS. The method employed a neutral aluminum oxide column for sample clean-up. Considering matrix effects, an isotope standard (vitamin K1-D7) was added to correct matrix interferences, as well as pretreatment losses and instrument variability. Spiked recoveries in model matrices were 88.3-90.1% for spinach, 84-110% for lotus roots, and 108-115.6% for grapes. The relative standard deviations (RSDs) were 1.0-7.1% for intra-day and 2.8-8.8% for inter-day. The limit of detection (LOD) and limit of quantification (LOQ) were 0.001 mg kg-1 and 0.004 mg kg-1, respectively. The method is sensitive and reliable, which is successfully applied to different vegetable and fruit matrices. Vitamin K1 in fruit samples ranged from 0.008 mg kg-1 to 0.401 mg kg-1, and in vegetable samples from 0.0032 mg kg-1 to 3.973 mg kg-1. © 2016 The Royal Society of Chemistry. Source
Sfakianaki S.,University of Crete |
Kouloumpi E.,Laboratory of Physicochemical Research |
Anglos D.,University of Crete |
Spyros A.,University of Crete
Magnetic Resonance in Chemistry
NMR spectroscopy is a powerful analytical tool for the identification and quantitative analysis of organic materials in a cultural heritage context. In this report, we present an analytical NMR protocol for the identification and semiquantification of egg yolk binders and mixed binding media that also contain a drying oil, namely linseed oil. The samples studied have been artificially and/or naturally aged in order to simulate the composition of organic materials in paintings. Analysis of the 1D and 2D NMR spectra showed that egg yolk can be identified even in bindingmedia of considerable age via signals originating fromcholesterol and/or cholesterol oxidation products present in the aged bindingmedium. Based on cholesterol-related and other lipid signals in the NMR spectra of egg yolk binders, amolecular marker (R/F) that suggests the presence of egg yolk in paint binders is proposed. Via thismarker, the presence of egg yolk in the organic material obtained from an early 18th century Greek icon is confirmed, and this is further verified by 2D NMR spectroscopy. It is demonstrated that NMR molecular markers developed to estimate the hydrolysis/oxidation state of oil paintings are also suitable for the analysis of egg yolk and mixed medium (egg yolk-linseed oil) binders, indicating the generality of the NMR methodological approach in the analysis of organic materials in a cultural heritage context. Copyright © 2014 John Wiley & Sons, Ltd. Source
Drakaki E.,National Technical University of Athens |
Kandyla M.,National Technical University of Athens |
Chatzitheodoridis E.,National Technical University of Athens |
Zergioti I.,National Technical University of Athens |
And 8 more authors.
Applied Physics A: Materials Science and Processing
Museum curators and archaeologists use analytical science to provide important information on artworks and objects. For example, scientific techniques provide information on artwork elemental composition, origin and authenticity, and corrosion products, while also finding use in the day-to-day conservation of many historical objects in museums and archaeological sites around the world. In this work two special cases are being discussed. In the first part of our work, physicochemical studies of an icon on a metal substrate were carried out using non-destructive, qualitative analysis of pigments and organic-based binding media, employing various microscopic and analytical techniques, such as Optical Fluorescence Microscopy, XRF, and Gas Chromatography. In the second part of our work, laser cleaning of late Roman coins has been performed using a Q-switched Nd:YAG laser (1064 nm, 6 ns) and a GaAlAs diode laser (780 nm, 90 ps). The corrosion products have been removed, while we observe increased concentrations in Ag, which is the main material of the silver plating found in late Roman coins. © 2010 Springer-Verlag. Source
Xu J.-J.,Laboratory of Physicochemical Research |
Zhou J.,Zhejiang University |
Huang B.-F.,Laboratory of Physicochemical Research |
Cai Z.-X.,Laboratory of Physicochemical Research |
And 3 more authors.
Journal of Separation Science
A simple and reliable method of ultra high performance liquid chromatography coupled with photo-diode array detection has been proposed for the simultaneous determination of deoxynivalenol and its acetylated derivatives in wheat flour and rice, especially focusing on the optimization of sample extraction, cleanup, and chromatographic separation conditions. Sample pretreatment consisted of a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure and a subsequent cleanup step based on solid-phase extraction. The method was extensively validated in wheat flour and rice, obtaining satisfactory analytical performance with good linearity (R2 ≥ 0.999), acceptable recoveries (80.0–104.4%), and repeatability (RSDs 1.3–10.7%). The limits of detection (21.7–57.4 μg/kg) and quantitation (72.3–191.4 μg/kg) for deoxynivalenols were lower than those usually permitted by various countries’ legislation in these food matrices. The method was applied to 34 wheat and rice samples. The results were further compared with results of ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Source