Zhao H.,Fudan University |
Jiang Y.,National Institute of Parasitic Diseases |
Cao Q.,Fudan University |
Hou Y.,Fudan University |
Wang C.,Shanghai Institute for Food and Drug Control
Biology of Reproduction | Year: 2012
The physiological hypoxic condition favors the angiogenesis in the placenta. However, it remains unclear how hypoxia regulates the invasion of human extravillous trophoblast cells. In the present study, we first showed that alpha5 integrin expression increased and alpha1 integrin expression decreased in human extravillous trophoblast cells cultured in 1% oxygen as compared with control cells cultured in 8% oxygen. Further data showed that the neutralizing antibody against alpha5 integrin increased the invasion of human extravillous trophoblast cells and the neutralizing antibody against alpha1 integrin inhibited the invasion of human extravillous trophoblast cells. Human extravillous trophoblast cells cultured in 1% oxygen showed reduced invasive capacity, which can be effectively blocked by alpha5 integrin neutralizing antibody. Moreover, human extravillous trophoblast cells exposed to 1% oxygen demonstrated increased expression of transforming growth factor-beta3 (TGFB3), and recombinant human TGFB3 inhibited the invasion of human extravillous trophoblast cells in a dosedependent manner. The neutralizing antibodies against alpha5 integrin and TGFB3 markedly abrogated hypoxia-induced invasion inhibition in human extravillous trophoblast cells. These data indicate that hypoxia may inhibit the invasion of human extravillous trophoblast cells through inducing the integrin switch from alpha1 integrin to alpha5 integrin and promoting TGFB3 expression. © 2012 by the Society for the Study of Reproduction, Inc.
Xiong Y.,Zhejiang Chinese Medical University |
Chen J.,China Pharmaceutical University |
Guo D.,Shanghai Institute for Food and Drug Control
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2014
Nobiliside A (Nob) is a new triterpenoid saponin separated from Holothuria noblilis. In this article, a liquid chromatography-electrospray ionization-tandem mass spectrometry method was established to quantify Nob, a hemolytic saponin, in rat blood and tissue homogenates. Standard curves were linear (r= 0.9988-0.9995) over the range 50-5000. ng/mL in blood and 100-10000. ng/g in tissues. The lower limit of quantification (LLOQ) was 50. ng/mL for Nob. The novel method was rapid, accurate, highly sensitive and highly selective. Using this method, the pharmacokinetics and biodistribution of Nob liposome and Nob solution in Sprague-Dawley rats after a single intravenous dose of 1. mg/kg were then investigated. Nob was cleared slowly from circulation. There was no significant difference of the pharmacokinetic parameters in blood between Nob solution and Nob liposome. The highest AUC of Nob was observed in liver for the two groups, followed by spleen, lungs, kidney and heart. Compared with Nob solution, Nob liposome showed much higher AUC in liver and spleen and much lower AUC in kidney, heart and lung, which might be one important reason for the decreased toxicity of Nob. © 2014 Elsevier B.V.
Chen G.,U.S. Department of Agriculture |
Miao S.,Shanghai Institute for Food and Drug Control
Journal of Agricultural and Food Chemistry | Year: 2010
Residues of malachite green (MG), gentian violet (GV), and their leuco metabolites in channel catfish muscle were individually determined by HPLC using diode array and fluorescence detectors and confirmed by tandem mass spectrometry. This detection scheme obviates a PbO2 reactor that converts leuco forms to chromatic forms for absorbance detection, therefore eliminating uncertainties in oxidant depletion and data integrity. Extraction was performed once in pH 3 McIlvaine buffer and acetonitrile, followed by cleanup using a polymeric strong cation-exchange column. Liquid-liquid extraction was excluded to provide an environmentally responsible and relatively rapid protocol. Spectrometric limits of detection (LOD; S/N = 3) for MG (λ = 620 nm) and GV (λ = 588 nm) were 0.38 and 0.26 ng/g with 44.5-49.2% and 92.2-101.4% recoveries (1-10 ng/g, n = 6), respectively. Fluorometric LOD (S/N = 3) for LMG and LGV (λex = 266 nm, λem = 360 nm) were 0.10 and 0.09 ng/g with 74.3-84.5% and 80.6-86.5% recoveries (1-10 ng/g, n = 6), respectively. This simplified protocol saves costs and meets the sensitivity requirements set by the Food and Drug Administration and the European Union. © 2010 American Chemical Society.
Chen G.,U.S. Department of Agriculture |
Liu G.,Shanghai Institute for Food and Drug Control |
Qin F.,Shanghai Institute for Food and Drug Control
Food Chemistry | Year: 2011
Oxytetracycline (OTC) is used worldwide to protect crops against bacterial diseases. The US Environmental Protection Agency approved its use in apple, pear, nectarine, and peach, and set residue tolerance at 350 ng g-1. A europium-sensitised luminescence (ESL) method was developed for in-situ determination of OTC residue in these fruits. After extraction in Na 2EDTA-NaCl-McIlvaine buffer at pH 4 and filtration, cleanup was performed using hydrophilic-lipophilic balance cartridges. ESL was measured using a portable time-resolved fluorometer. The signal responded linearly over three orders of magnitude (10-10000 ng g-1) with 17-50 ng g -1 limits of quantitation and 2% averaged relative standard deviation. Recoveries were 84% and 82% at 100 and 350 ng g-1, respectively. Inter-laboratory validation was performed by HPLC-MS/MS. © 2011 Elsevier Ltd. All rights reserved.
Chen G.,U.S. Department of Agriculture |
Liu G.,Shanghai Institute for Food and Drug Control
Sensing and Instrumentation for Food Quality and Safety | Year: 2011
Oxytetracycline residue in shrimp muscle was determined using a portable time-resolved analyzer. After extraction in EDTA-metaphosphoric acid and filtration, the analyte was cleaned up using hydrophilic-lipophilic balance cartridges. Europium-sensitized luminescence (ESL) was measured at λ ex = 385 nm and λ em = 620 nm. Recoveries were 80. 3 and 79. 7% at 100 ng g -1 and 2 μg g -1, respectively. The signal intensity was linear (r 2 ≥ 0.996) in each decade in the 5-5,000 ng g -1 range. Averaged relative standard deviation was ~2% and limit of detection was 8. 3 ng g -1. This instrument-method combination enabled sensitive in-situ quantification of OTC residue in shrimp. The ESL results were validated by HPLC-MS/MS. © 2012 Science+Business Media, LLC.
Chen G.,U.S. Department of Agriculture |
Du Y.,Shanghai Institute for Food and Drug Control
Journal of Agricultural and Food Chemistry | Year: 2011
Danofloxacin (DANO) residue in bovine muscle was screened at 200 ng/g by terbium-sensitized luminescence (TSL) directly measured on 10 x 6 mm C18 sorbent strips. The analyte was first adsorbed on sorbent surface by immersion in defatted homogenates. After reagent application and desiccation, TSL was directly measured on sorbent surfaces at λex = 273 nm and λem = 546 nm. The luminescence intensity was linearly dependent on DANO concentration in the 0-1000 ng/g range (R2 = 0.9967). A threshold was established at x200 - 3σ 200, where x200 and σ200 are the mean and standard deviation, respectively, of the DANO signals at 200 ng/g. Among 48 blind samples randomly fortified at 0-1000 ng/g, 45 were screened correctly and 3 negative samples were presumed positive. This simple screening protocol has the potential to significantly reduce sample numbers and hence improve sample throughput and save assay costs. © 2011 American Chemical Society.
Koesukwiwat U.,U.S. Department of Agriculture |
Koesukwiwat U.,Chulalongkorn University |
Lehotay S.J.,U.S. Department of Agriculture |
Miao S.,Shanghai Institute for Food and Drug Control |
Leepipatpiboon N.,Chulalongkorn University
Journal of Chromatography A | Year: 2010
A higher monitoring rate is highly desirable in the labs, but this goal is typically limited by sample throughput. In this study, we sought to assess the real-world applicability of fast, low-pressure GC-time-of-flight MS (LP-GC/TOFMS) for the identification and quantification of 150 pesticides in tomato, strawberry, potato, orange, and lettuce samples. Buffered and unbuffered versions of QuEChERS (which stands for " quick, easy, cheap, effective, rugged, and safe" ) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for clean-up were compared for sample preparation. For clean-up of all sample types, a combination of 150mg MgSO4, 50mg primary secondary amine (PSA), 50mg C18, and 7.5mg graphitized carbon black (GCB) per mL extract was used. No significant differences were observed in the results between the different sample preparation versions. QuEChERS took <10min per individual sample, or <1h for two chemists to prepare 32 pre-homogenized samples, and using LP-GC/TOFMS, <10min run time and <15min cycle time allowed >32 injections in 8h. Overall, >126 analytes gave recoveries (3 spiking levels) in the range of 70-120% with <20% RSD. The results indicate that LP-GC/TOFMS for GC-amenable analytes matches UHPLC-MS/MS in terms of sample throughput and turnaround time for their routine, concurrent use in the analysis of a wide range of analytes in QuEChERS extracts to achieve reliable quantification and identification of pesticide residues in foods. © 2010.
Mao D.-Z.,Shanghai Institute for Food and Drug Control |
Weng X.-X.,Shanghai Institute for Food and Drug Control |
Yang Y.-J.,Shanghai Institute for Food and Drug Control
Journal of Raman Spectroscopy | Year: 2012
Sildenafil and tadalafil are inhibitors of phosphodiesterase type 5, which are frequently added into healthcare products. The objective of this study was to evaluate the possibility of using micro-Raman spectroscopy as a non-destructive technique to screen for sildenafil and tadalafil in adulterated healthcare products. Using a viewing microscope, the suspect area of healthcare products was selected, which had a discernable crystal form or shape from the surrounding zone. Optimization of instrumental parameters of the Raman spectrometer was chosen to reduce the background fluorescence, and the Raman spectra were collected. The spectra collected were compared with the standard Raman spectra of pure sildenafil and tadalafil. Samples with an identifiable Raman signature to that of sildenafil or tadalafil could be confirmed using liquid chromatography-mass spectrometry (LC/MS). Additionally, wavelet denoising combined with similarity calculation was used to establish an automated approach for discrimination of adulterated healthcare products. Correlation coefficient was chosen for similarity calculation based on the spectra collected and the standard Raman spectra of pure sildenafil and tadalafil. We compared ten samples, secured by administrative authorities in Shanghai, to analyse and demonstrate the capabilities of our proposed method. We established six samples containing sildenafil or tadalafil warranting analysis using LC/MS. Thus, the use of micro Raman spectroscopy provides a quick, convenient and non-destructive method for screening adulterated chemicals in healthcare products. Raman spectroscopy combined with similarity calculation requires little training after spectra library is developed, thus showing great promise to identify the adulterated healthcare products in the future. Copyright © 2012 John Wiley & Sons, Ltd.
Wang S.,Zhejiang University |
Cheng L.,Zhejiang University |
Ji S.,Shanghai Institute for Food and Drug Control |
Wang K.,Shanghai Institute for Food and Drug Control
Journal of Pharmaceutical and Biomedical Analysis | Year: 2014
This work reported an efficient and accurate liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of seventeen mycotoxins in Puerariae lobatae radix, a frequently used traditional Chinese medicine (TCM). The effects of four different clean-up methods, including TC-M160, TC-T220, Mycosep 227, and QuEChERS method, on the recoveries of mycotoxins were investigated and compared. Finally, TC-M160 was chosen for better recovery and repeatability for mycotoxins analysis. The analytes were separated on an Agilent ZORBAX SB C18 column (4.6mm×250mm, 5μm particle size), and eluted with a mobile phase consisting of (A) water containing 0.1% formic acid and (B) acetonitrile containing 0.1% formic acid at a flow rate of 0.6mL/min. The separated compounds were detected by a triple quadrupole mass spectrometer operating in positive electrospray ionization with multiple reaction monitoring (MRM) mode. The results of method validation accorded with the requirement of analytical method for mycotoxins in COMMISSION REGULATION (EC) No 401/2006. The developed method was successfully applied for determination of mycotoxins in seventeen batches of Puerariae lobatae radix collected from different provinces of China. Three batches of them were found with contamination of mycotoxins AFB1 at (0.751±0.176)μg/kg, T-2 at (1.10±0.01)μg/kg, and T-2 at (0.853±0.044)μg/kg, respectively. The results demonstrated that the proposed method was suitable for monitoring mycotoxins residues in Puerariae lobatae radix. © 2014 Elsevier B.V.
Chen G.-L.,Shanghai Institute for Food and Drug Control |
Fang Y.-Y.,Shanghai Institute for Food and Drug Control
Methods in Molecular Biology | Year: 2011
This chapter describes the LC-MS/MS methods for the determination of antibiotics residues in food matrices. The types of antibiotics include β-lactam antibiotics, sulfonamides, tetracyclines, fluoroquinolones, nitrofurans, and chloramphenicol (CAP). The food matrices are mainly from animal origin, such as animal tissues, fishes (marine products), eggs, milk, honey, and so on. The methods and procedures are covered, including three parts: (1) Liquid chromatographic conditions, (2) mass spectrometer conditions, including ionization source, analyzer, and acquisition, and (3) extraction and clean-up methods. In each case, the standard operating procedures (SOPs) for analysis are given with sensitivity, linearity, precision, and recovery. Some criteria of maximum residue limits (MRLs) from the legislation are listed. © 2011 Springer Science+Business Media, LLC.