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https://www.readbyqxmd.com/read/28110498/neutral-losses-of-sodium-benzoate-and-benzoic-acid-in-the-fragmentation-of-the-m%C3%A2-%C3%A2-na-ions-of-methoxyfenozide-and-tebufenozide-via-intramolecular-rearrangement-in-electrospray-ionization-tandem-mass-spectrometry
#1
Yunfeng Chai, Guanwei Gao, Shanshan Shen, Xin Liu, Chengyin Lu
RATIONALE: Electrospray ionization (ESI) tandem mass spectrometry can be applied to determine structural information about organic compounds. The [M + Na](+) ion is one of the major precursor ions in ESI mass spectrometry, but its fragmentation mechanism study is still insufficient. This study reveals the interesting fragmentation reactions of the [M + Na](+) ions of methoxyfenozide and tebufenozide. METHODS: The fragmentations of the [M + Na](+) , [M + Li](+) , and [M + H](+) ions of methoxyfenozide and tebufenozide were studied using a hybrid quadrupole-orbitrap mass spectrometer and an ion trap mass spectrometer...
February 15, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28110221/simultaneous-determination-of-eight-flavonoids-in-plasma-using-lc-ms-ms-and-application-to-a-pharmacokinetic-study-after-oral-administration-of-pollen-typhae-extract-to-rats
#2
Xie-An Yu, John Teye Azietaku, Jin Li, Jun Cao, Mingrui An, Jun He, Xiu-Mei Gao, Yan-Xu Chang
A sensitive, reliable and validated LC-MS/MS method was developed to determine the presence of eight flavonoids (catechin, typhaneoside, isorhamnetin-3-O-neohesperidoside, astragalin, isorhamnetin-3-O-β-d-glucoside, naringenin, kaempferol and isorhamnetin) in rat plasma. Puerarin was selected as the internal standard. Precipitation of the protein method with acetonitrile was used to extract these flavonoids from the rat plasma samples. The analysis was carried out on an Eclipse plus C18 column (4.6 mm×100mm, 1...
January 15, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28110081/isolation-and-partial-characterization-of-an-immunogenic-antigen-of-giardia-lamblia
#3
Jael Quintero, Alejandra Valdez, Brenda Samaniego, Gloria Lopez-Romero, Humberto Astiazaran-Garcia, Lucila Rascon, Linda Breci, Adriana Garibay-Escobar, Ramón Robles-Zepeda, Carlos Velazquez
Humoral and cellular immune responses play an important role during Giardia lamblia infection. Several Giardia proteins have been identified as immunogenic antigens based on their elicited humoral immune response. Poorly is known about Giardia antigens that stimulate a cellular immune response. The main purpose of this study was to isolate and partial characterize an immunogenic antigen (5G8) of G. lamblia. The 5G8 protein was isolated from G. lamblia trophozoite lysates by affinity chromatography using moAb 5G8-coupled CNBr-Sepharose...
January 18, 2017: Parasitology International
https://www.readbyqxmd.com/read/28109742/development-of-a-new-uplc-esi-ms-ms-method-for-the-determination-of-biopterin-and-neopterin-in-dried-blood-spot
#4
Silvia Santagata, Emanuele Di Carlo, Carla Carducci, Vincenzo Leuzzi, Antonio Angeloni, Claudia Carducci
BACKGROUND: (6R)-5,6,7,8-tetrahydrobiopterin (BH4) deficiencies are rare inherited defects of synthesis or regeneration of BH4. Due to the resulting hyperphenylalaninemia (HPA), some of them are detectedby newborn screening and require the assessment of the pattern of neopterin (Neo) and biopterin (Bio) excretion in urine to be confirmed. Aim of presentstudy was to develop a method for the measurement of these diagnostic biomarkers in dried blood spot (DBS). METHODS: After DBS extraction, samples were filtered and injected into the UPLC column coupled with atandem mass spectrometer working in positive electrospray ionization...
January 18, 2017: Clinica Chimica Acta; International Journal of Clinical Chemistry
https://www.readbyqxmd.com/read/28109047/novel-antiplatelet-role-for-a-protein-disulfide-isomerase-targeted-peptide-evidence-of-covalent-binding-to-c-terminal-cghc-redox-motif
#5
H R Sousa, R S Gaspar, E M L Sena, S A da Silva, J L de L Fontelles, T L S Araújo, M Mastrogiovanni, D M Fries, A P S Azevedo-Santos, F R M Laurindo, A Trostchansky, A M Paes
Protein disulfide isomerase (PDI) plays a major role in platelet aggregation and its inhibitors have emerged as novel antithrombotic drugs. In previous work, we designed a peptide based on PDI redox motif (CGHC) that inhibited both PDI reductase activity and PDI-modulated superoxide generation by neutrophil Nox2. Thus, we hypothesized this peptide would also inhibit platelet aggregation by association to surface PDI. Three peptides were used: CxxC, containing the PDI redox motif; Scr, presenting a scrambled sequence of the same residues and AxxA, with cysteines replaced by alanine...
January 21, 2017: Journal of Thrombosis and Haemostasis: JTH
https://www.readbyqxmd.com/read/28108381/metabolomic-study-of-the-intervention-effects-of-shuihonghuazi-formula-a-traditional-chinese-medicinal-formulae-on-hepatocellular-carcinoma-hcc-rats-using-performance-hplc-esi-tof-ms
#6
Yongrui Bao, Shuai Wang, Xinxin Yang, Li Tianjiao, Mingyue Xia, Xiansheng Meng
ETHNOPHARMACOLOGICAL RELEVANCE: Metabolomics is the comprehensive assessment of endogenous metabolites of a biological system in a holistic context, and its property consists with the global view of Traditional Chinese Medicine (TCM). Shuihonghuazi Formula (SHHZF) has been used for liver cancer early treatment in clinical for more than thirty years, but its mechanism remains unclear completely. This paper was designed to explore the therapeutic effects of SHHZF on liver cancer and its metabolomic characters...
January 17, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28107974/analysis-of-bromophenols-in-various-aqueous-samples-using-solid-phase-extraction-followed-by-hplc-ms-ms
#7
Xiyuan Chi, Jiyan Liu, Miao Yu, Zhouqing Xie, Guibin Jiang
A reliable and effective method for simultaneous analysis of trace amount of bromophenols (BPs) in various aqueous samples was developed in this study. The aqueous samples must be acidified after sampling to prevent the fast degradation of bromophenols. Solid-phase extraction was chosen to extract and purify the water samples. High performance liquid chromatography coupled with tandem mass spectrometry with an electrospray ionization source (HPLC-ESI-MS/MS) was used for following identification and quantification...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107956/electro-kinetic-assisted-electrospray-ionization-for-enhanced-complex-sample-analysis
#8
Zezhen Zhang, Muyi He, Lingyan Liu, Xingchuang Xiong, Xiang Fang, Wei Xu
In this work, an electro-kinetic assisted electrospray ionization (EK-ESI) source is proposed and characterized. In EK-ESI, an additional auxiliary electric field is introduced in the liquid flow of a nano-ESI. While traveling forward in the electrospray flow, charged analytes also experience a reverse electric field, which pushes them backwards. As a result, analytes could be separated preliminarily based on their electrophoretic mobility during the electrospray process. Experiments show that EK-ESI can reduce charge competition effects in the ESI source and increase biomolecule detection sensitivities...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107951/investigating-the-structural-transitions-of-proteins-during-dissolution-by-mass-spectrometry
#9
Xiaoyun Gong, Xingchuang Xiong, Lin Qi, Xiang Fang
An appropriate solvent environment is essential for the implementation of biological functions of proteins. Interactions between protein residues and solvent molecules are of great importance for proteins to maintain their active structure and catalyze biochemical reactions. In this study, we investigated such interactions and studied the structural transitions of proteins during their dissolution process. Our previously developed technique, namely solvent assisted electric field induced desorption/ionization, was used for the dissolution and immediate ionization of proteins...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107934/tuning-sensitivity-of-a-simple-hydrazone-for-selective-fluorescent-turn-on-chemo-sensing-of-al-3-and-its-application-in-living-cells-imaging
#10
Faiz-Ur Rahman, Amjad Ali, Saira Khan Khalil, Rong Guo, Peng Zhang, Hui Wang, Zhan-Ting Li, Dan-Wei Zhang
Salicylaldehyde based hydrazones 2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (SMPH), 4-methyl-2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (MSMPH) and 4-fluoro-2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (FSMPH) were prepared and structurally characterized. These hydrazones exhibited fluorescence "turn on" response toward Al(3+) in dimethyl formamide/water (DMF/H2O) (1: 1) mixture. SMPH showed enhanced emission (70 folds) as compared to MSMPH (46 folds) and FSMPH (28 folds) upon the addition of 3 equivalents of Al(3+)...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107791/design-and-synthesis-of-28-hydroxy-protopanaxadiol-as-a-novel-probe-template
#11
Ze-Yun Liu, Heng-Yuan Zhang, Yi Bi, Xian-Xuan Liu, Jing Lu, Xiao-Chen Zhang, Jin-Yi Xu, Chong-Zhi Wang, Chun-Su Yuan
To explore the antitumour mechanism of 20(S)-protopanaxadiol (PPD) while maintaining its uncovered pharmacological active site 3-hydroxyl, 28-hydroxy protopanaxadiol (17), a small molecular probe template of PPD was first designed and synthesised based on the Baldwin's reaction. Thus, 28-hydroxyl of 17 was built successfully as a derivatized site of molecular probe's functional and report groups. The important intermediates and final product were confirmed by ESI-MS and nuclear magnetic resonance spectra with good yield...
January 20, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28107780/myb12-and-myb22-play-essential-roles-in-proanthocyanidin-and-flavonol-synthesis-in-red-fleshed-apple-malus-sieversii-f-niedzwetzkyana
#12
Nan Wang, Haifeng Xu, Shenghui Jiang, Zongying Zhang, Ninglin Lu, Huarong Qiu, Changzhi Qu, Yicheng Wang, Shujing Wu, Xuesen Chen
Flavonoids are major polyphenol compounds in plant secondary metabolism. Compared with cultivated apples, wild red-fleshed apples (Malus sieversii f. niedzwetzkyana) are excellent resources because of their high flavonoid content. In this work, R6R6, R6R1 and R1R1 genotypes were identified in an F1 segregating population of M. sieversii f. niedzwetzkyana. Significant differences in flavonoid compositions and contents were detected among the three genotypes by UPLC-ESI-TOF/MS analysis. Furthermore, two putative flavonoid-related genes encoding R2R3-MYB transcription factors, designated MYB12 and MYB22, were cloned and characterized...
January 20, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28107689/development-and-validation-of-a-liquid-chromatography-tandem-mass-spectrometry-method-for-the-assay-of-tafamidis-in-rat-plasma-application-to-a-pharmacokinetic-study-in-rats
#13
Hun-Chan Hyun, Jong-Woo Jeong, Hye-Rim Kim, Ji-Hoon Oh, Jong-Hwa Lee, Sungwook Choi, Yeon-Soo Kim, Tae-Sung Koo
Tafamidis is a first-in-class inhibitor of transthyretin amyloid fibril formation. It has been available in Argentina, Japan, and Mexico for the treatment of transthyretin amyloidosis in adult patients with early-stage symptomatic polyneuropathy. In this study, a rapid and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the assay of tafamidis in rat plasma. The method was also assessed for its applicability to pharmacokinetic studies in rats. Tafamidis was extracted from rat plasma by the liquid-liquid extraction method using hydrochloric acid and ethyl acetate...
January 10, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28105858/hplc-ms-ms-method-for-dexmedetomidine-quantification-with-design-of-experiments-approach-application-to-pediatric-pharmacokinetic-study
#14
Oliwia Szerkus, Wiktoria Struck-Lewicka, Marta Kordalewska, Ewa Bartosińska, Renata Bujak, Agnieszka Borsuk, Agnieszk Bienert, Alicja Bartkowska-Śniatkowska, Justyna Warzybok, Paweł Wiczling, Antoni Nasal, Roman Kaliszan, Mchał Jan Markuszewski, Danuta Siluk
AIM: The purpose of this work was to develop and validate a rapid and robust LC-MS/MS method for the determination of dexmedetomidine (DEX) in plasma, suitable for analysis of a large number of samples. METHOD: Systematic approach, Design of Experiments, was applied to optimize ESI source parameters and to evaluate method robustness, therefore, a rapid, stable and cost-effective assay was developed. The method was validated according to US FDA guidelines. LLOQ was determined at 5 pg/ml...
January 20, 2017: Bioanalysis
https://www.readbyqxmd.com/read/28105811/palladium-catalyzed-denitrogenative-synthesis-of-aryl-ketones-from-arylhydrazines-and-nitriles-using-o2-as-sole-oxidant
#15
Xu Wang, Yubing Huang, Yanli Xu, Xiaodong Tang, Wanqing Wu, Huanfeng Jiang
An efficient and simple palladium-catalyzed approach for the synthesis of aryl ketones from low-cost nitriles and arylhydrazines using molecular oxygen (O2) as sole oxidant via C-N bond cleavage is reported. Various aryl ketones were synthesized in moderate to good yields under mild conditions. A possible mechanism involving the PdII/Pd0 catalytic cycle process is depicted, and a cationic palladium intermediate was detected by ESI-MS.
January 20, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28103535/down-regulation-of-histone-deacetylase-4-5-and-6-as-a-mechanism-of-synergistic-enhancement-of-apoptosis-in-human-lung-cancer-cells-treated-with-the-combination-of-a-synthetic-retinoid-am80-and-green-tea-catechin
#16
Yukiko Oya, Anupom Mondal, Anchalee Rawangkan, Sonthaya Umsumarng, Keisuke Iida, Tatsuro Watanabe, Miki Kanno, Kaori Suzuki, Zhenghao Li, Hiroyuki Kagechika, Koichi Shudo, Hirota Fujiki, Masami Suganuma
(-)-Epigallocatechin gallate (EGCG), a green tea catechin, acts as a synergist with various anticancer drugs, including retinoids. Am80 is a synthetic retinoid with a different structure from all-trans-retinoic acid: Am80 is now clinically utilized as a new drug for relapsed and intractable acute promyelocytic leukemia patients. Our experiments showed that the combination of EGCG and Am80 synergistically induced both apoptosis in human lung cancer cell line PC-9 and up-regulated expressions of growth arrest and DNA damage-inducible gene 153 (GADD153), death receptor 5, and p21(waf1) genes in the cells...
January 8, 2017: Journal of Nutritional Biochemistry
https://www.readbyqxmd.com/read/28103258/revisiting-greek-propolis-chromatographic-analysis-and-antioxidant-activity-study
#17
Konstantinos M Kasiotis, Pelagia Anastasiadou, Antonis Papadopoulos, Kyriaki Machera
Propolis is a bee product that has been extensively used in alternative medicine and recently has gained interest on a global scale as an essential ingredient of healthy foods and cosmetics. Propolis is also considered to improve human health and to prevent diseases such as inflammation, heart disease, diabetes and even cancer. However, the claimed effects are anticipated to be correlated to its chemical composition. Since propolis is a natural product, its composition is consequently expected to be variable depending on the local flora alignment...
2017: PloS One
https://www.readbyqxmd.com/read/28103012/a-bi-modal-cationic-and-water-soluble-calix-4-arene-conjugate-design-synthesis-characterization-and-transfection-of-rfp-encoded-plasmid-in-cancer-cells
#18
Kushal Samanta, Dnyanesh S Ranade, Aekta Upadhyay, Prasad Padmakar Kulkarni, Chebrolu Pulla Rao
A new bimodal fluorescent cationic calix[4]arene (L1) conjugate has been synthesized in multiple steps and well characterized by NMR and ESI-MS techniques. L1 has been investigated for its DNA binding ability by various spectroscopy techniques like, absorption, fluorescence and circular dichroism (CD). The formation of L1-DNA complex has been confirmed by the gel electrophoresis in presence of incremental concentration of L1. To visualize the packing of the plasmid (pBR322), detailed tapping mode AFM study has been performed, which revealed blob like structure of plasmid upon addition of the incremental amount of L1...
January 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28102932/antileukemic-action-of-novel-diamine-pt-ii-halogenido-complexes-comparison-of-the-representative-novel-pt-ii-with-corresponding-pt-iv-complex
#19
Sonja Misirlić Denčić, Jelena Poljarević, Andjelka M Isakovic, Ivanka Marković, Tibor J Sabo, Sanja Grgurić-Šipka
This study presents the synthesis, characterization and antitumor action of five new Pt(II) halogenido, chlorido and iodido, complexes with edda type of ligands. (S,S)-ethylendiamine-N,N'-di-2-(3-cyclohexyl)propanoic acid dihydrochloride and its methyl, ethyl and n-propyl esters, were prepared according to the previously reported procedure. All investigated complexes were characterized by IR, ESI-MS, ((1) H, (13) C and HMBC) NMR spectroscopy and elemental analysis. Their cytotoxic action was investigated in four human tumor cell lines: promyelocytic (HL-60) and lymphocytic (REH) leukemia, glioma (U251) and lung carcinoma (H460)...
January 19, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28102710/development-and-validation-of-a-uplc-ms-ms-method-for-simultaneous-determination-of-fotagliptin-and-its-two-major-metabolites-in-human-plasma-and-urine
#20
Zhenlei Wang, Ji Jiang, Pei Hu, Qian Zhao
AIM: Fotagliptin is a novel dipeptidyl peptidase IV inhibitor under clinical development for the treatment of Type II diabetes mellitus. The objective of this study was to develop and validate a specific and sensitive ultra-performance liquid chromatography (UPLC)-MS/MS method for simultaneous determination of fotagliptin and its two major metabolites in human plasma and urine. Methodology & results: After being pretreated using an automatized procedure, the plasma and urine samples were separated and detected using a UPLC-ESI-MS/MS method, which was validated following the international guidelines...
January 19, 2017: Bioanalysis
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