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https://www.readbyqxmd.com/read/28215026/separation-of-peptides-on-superficially-porous-particle-based-macrocyclic-glycopeptide-liquid-chromatography-stationary-phases-consideration-of-fast-separations
#1
Rasangi M Wimalasinghe, Zachary S Breitbach, Jauh T Lee, Daniel W Armstrong
Macrocyclic glycopeptide based liquid chromatography stationary phases are known for their highly selective peptide separations. Fast and ultrafast (t R < 1 min) high-efficiency separations were achieved with superficially porous particle (SPP)-based stationary phases. Separations of pharmaceutically important classes of peptides such as enkephalins and bradykinins have been achieved in less than 5 min in isocratic elution modes. Selectivity for peptides structurally similar to one another was increased with use of teicoplanin-based stationary phases compared with commercial C18 stationary phases...
February 18, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28214451/a-novel-lc-ms-ms-method-for-the-simultaneous-quantification-of-topiramate-and-its-main-metabolites-in-human-plasma
#2
Daniela Milosheska, Robert Roškar
The aim of the present report was to develop and validate simple, sensitive and reliable LC-MS/MS method for quantification of topiramate (TPM) and its main metabolites: 2,3-desisopropylidene TPM, 4,5-desisopropylidene TPM, 10-OH TPM and 9-OH TPM in human plasma samples. The most abundant metabolite 2,3-desisopropylidene TPM was isolated from patients urine, characterized and afterwards used as an authentic standard for method development and validation. Sample preparation method employs 100μL of plasma sample and liquid-liquid extraction with a mixture of ethyl acetate and diethyl ether as extraction solvent...
February 3, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28213312/multiple-myocardial-abscesses-secondary-to-late-stent-infection
#3
Ayman Elbadawi, Marwan Saad, Islam Y Elgendy, Aniqa Zafar, Ming-Yan Chow
A 53-year-old woman presented to our hospital with dizziness and low-grade fever. She underwent percutaneous coronary intervention to the obtuse marginal artery with a drug-eluting stent 20 months prior to this presentation. Physical examination was remarkable for bradycardia. Electrocardiogram showed a junctional rhythm with heart rate of 35 bpm. Blood and urine cultures were negative. Despite successful urgent pacemaker placement, she had cardiac arrest the following day with unsuccessful cardiopulmonary resuscitation attempt...
February 2, 2017: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
https://www.readbyqxmd.com/read/28213249/on-line-flow-injection-molecularly-imprinted-solid-phase-extraction-for-the-preconcentration-and-determination-of-1-hydroxypyrene-in-urine-samples
#4
Montserrat Serrano, Mónica Bartolomé, Juan Carlos Bravo, Gema Paniagua, Judith Gañan, Alejandrina Gallego-Picó, Rosa María Garcinuño
New analytical strategies tend to automation of sample pre-treatment and flow analysis techniques provided a number of enhanced analytical methods allowing high throughput. Flow techniques are usually faster, more robust and more flexible than their batch equivalents. In addition, flow methods use less sample and reagent amounts and reduce analytical costs and waste. A flow injection solid-phase extraction pre-concentration system using a molecularly imprinted polymer (MIP) packed micro-column was developed for the determination of 1-hydroxypyrene in human urine with fluorescence detection...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28213230/the-pentafluorophenyl-stationary-phase-shows-a-unique-separation-efficiency-for-performing-fast-chromatography-determination-of-highbush-blueberry-anthocyanins
#5
Barbora Šmídová, Dalibor Šatínský, Kateřina Dostálová, Petr Solich
A high-performance liquid chromatography method using an alternative pentafluorophenyl (PFP) core-shell stationary phase has been developed and used for rapid separation of 23 anthocyanins in a highbush blueberry Bluehaven cultivar. A high efficiency of separation of anthocyanins was achieved in the core-shell column Kinetex PFP, 150×4.6mm (particle size 2.6µm) with a 5×4.6mm precolumn, using a simple linear gradient elution with a mobile phase of acetonitrile and a water solution of 2% formic acid at a flow rate of 1...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28212269/separation-and-characterization-of-angiotensin-i-converting-enzyme-ace-inhibitory-peptides-from-saurida-elongata-proteins-hydrolysate-by-imac-ni-2
#6
Lixia Sun, Shanguang Wu, Liqin Zhou, Feng Wang, Xiongdiao Lan, Jianhua Sun, Zhangfa Tong, Dankui Liao
Lizard fish protein hydrolysates (LFPH) were prepared from Lizard fish (Saurida elongata) proteins possessing powerful angiotensin I converting enzyme (ACE) inhibitory activity and the fraction (LFPH-I) with high ACE inhibitory activity was obtained through ultrafiltration. The active Fraction (F2) was isolated from LFPH-I using immobilized metal affinity chromatography (IMAC-Ni(2+)). Analysis of amino acid levels revealed that F2 eluted from IMAC was enriched in Met, His, Tyr, Pro, Ile, and Leu compared to the crude peptide LFPH-I...
February 15, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28211603/impact-of-six-versus-12-months-of-dual-antiplatelet-therapy-in-patients-with-drug-eluting-stent-implantation-after-risk-stratification-with-the-residual-syntax-score-results-from-a-secondary-analysis-of-the-i-love-it-2-trial
#7
Miaohan Qiu, Yi Li, Jing Li, Kai Xu, Quanmin Jing, Shaohong Dong, Zhe Jin, Pitian Zhao, Bo Xu, Yaling Han
BACKGROUND: The optimal duration of dual antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation remains undetermined, especially for those at high risk of cardiac events postprocedure. OBJECTIVES: This study was aimed to investigate the impact of 6 versus 12 months of DAPT after DES implantation based on risk stratification with the residual SYNTAX score (rSS). METHODS: A total of 2737 patients in the I-LOVE-IT 2 trial were grouped according to rSS status (low rSS [rSS = 0, n = 1474] versus high rSS [rSS > 0, n = 1263]) and DAPT duration (6 months vs...
February 17, 2017: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/28211327/results-from-a-round-robin-test-for-the-ecotoxicological-evaluation-of-construction-products-using-two-leaching-tests-and-an-aquatic-test-battery
#8
Stefan Gartiser, Ines Heisterkamp, Ute Schoknecht, Michael Burkhardt, Monika Ratte, Outi Ilvonen, Frank Brauer, Jan Brückmann, André Dabrunz, Philipp Egeler, Andrea-Maria Eisl, Ute Feiler, Ines Fritz, Sabina König, Herbert Lebertz, Pascal Pandard, Gabriele Pötschke, Dirk Scheerbaum, Frank Schreiber, Přemysl Soldán, Roland Weiß, Reinhilde Weltens
A European round robin test according to ISO 5725-2 was conceptually prepared, realised, and evaluated. The aim was to determine the inter-laboratory variability of the overall process for the ecotoxicological characterization of construction products in eluates and bioassays. To this end, two construction products BAM-G1 (granulate) and HSR-2 (roof sealing sheet), both made of EPDM polymers (rubber), were selected. The granular construction product was eluted in a one stage batch test, the planar product in the Dynamic Surface Leaching test (DSLT)...
February 2, 2017: Chemosphere
https://www.readbyqxmd.com/read/28209962/characterization-of-celiac-disease-related-oat-proteins-bases-for-the-development-of-high-quality-oat-varieties-suitable-for-celiac-patients
#9
María J Giménez, Ana Real, M Dolores García-Molina, Carolina Sousa, Francisco Barro
Some studies have suggested that the immunogenicity of oats depends on the cultivar. RP-HPLC has been proposed as a useful technique to select varieties of oats with reduced immunogenicity. The aim of this study was to identify both the avenin protein patterns associated with low gluten content and the available variability for the development of new non-toxic oat cultivars. The peaks of alcohol-soluble avenins of a collection of landraces and cultivars of oats have been characterized based on the RP-HPLC elution times...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28209475/quantification-of-psp-toxins-in-toxic-shellfish-matrices-using-post-column-oxidation-liquid-chromatography-and-pre-column-oxidation-liquid-chromatography-methods-suggests-post-column-oxidation-liquid-chromatography-as-a-good-monitoring-method-of-choice
#10
Verónica Rey, Ana M Botana, Luis M Botana
Different shellfish samples were analyzed by Pre- and Post-Column Oxidation Liquid Chromatography to compare the toxins profiles and get information about the degree of accomplishment of both methods. Comparison of the results obtained, the linear correlation coefficient (r(2) = 0.94) and the paired t test (two tails, α = 0.05), indicated that there were not significant differences between both sets of data. Nevertheless, important differences related to toxins profiles were found: it was remarkable the difference in results for both Gonyautoxins 1 and 4 and Decarbamoylgonyautoxins 2 and 3, depending on the method of choice, due to an overestimation in the Pre-Column method...
February 13, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28208794/qsrr-modeling-for-metabolite-standards-analyzed-by-two-different-chromatographic-columns-using-multiple-linear-regression
#11
Chrysostomi Zisi, Ioannis Sampsonidis, Stella Fasoula, Konstantinos Papachristos, Michael Witting, Helen G Gika, Panagiotis Nikitas, Adriani Pappa-Louisi
Modified quantitative structure retention relationships (QSRRs) are proposed and applied to describe two retention data sets: A set of 94 metabolites studied by a hydrophilic interaction chromatography system under organic content gradient conditions and a set of tryptophan and its major metabolites analyzed by a reversed-phase chromatographic system under isocratic as well as pH and/or simultaneous pH and organic content gradient conditions. According to the proposed modification, an additional descriptor is added to a conventional QSRR expression, which is the analyte retention time, tR(R), measured under the same elution conditions, but in a second chromatographic column considered as a reference one...
February 9, 2017: Metabolites
https://www.readbyqxmd.com/read/28208634/rna-eluting-surfaces-for-the-modulation-of-gene-expression-as-a-novel-stent-concept
#12
Olivia Koenig, Diane Zengerle, Nadja Perle, Susanne Hossfeld, Bernd Neumann, Andreas Behring, Meltem Avci-Adali, Tobias Walker, Christian Schlensak, Hans Peter Wendel, Andrea Nolte
Presently, a new era of drug-eluting stents is continuing to improve late adverse effects such as thrombosis after coronary stent implantation in atherosclerotic vessels. The application of gene expression-modulating stents releasing specific small interfering RNAs (siRNAs) or messenger RNAs (mRNAs) to the vascular wall might have the potential to improve the regeneration of the vessel wall and to inhibit adverse effects as a new promising therapeutic strategy. Different poly (lactic-co-glycolic acid) (PLGA) resomers for their ability as an siRNA delivery carrier against intercellular adhesion molecule (ICAM)-1 with a depot effect were tested...
February 10, 2017: Pharmaceuticals
https://www.readbyqxmd.com/read/28207866/a-novel-mechanism-of-metal-gel-shift-by-histidine-rich-ni2-binding-hpn-protein-from-helicobacter-pylori-strain-ss1
#13
Rahul Mahadev Shelake, Yuki Ito, Junya Masumoto, Eugene Hayato Morita, Hidenori Hayashi
Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) is a universally used method for determining approximate molecular weight (MW) in protein research. Migration of protein that does not correlate with formula MW, termed "gel shifting" appears to be common for histidine-rich proteins but not yet studied in detail. We investigated "gel shifting" in Ni2+-binding histidine-rich Hpn protein cloned from Helicobacter pylori strain SS1. Our data demonstrate two important factors determining "gel shifting" of Hpn, polyacrylamide-gel concentration and metal binding...
2017: PloS One
https://www.readbyqxmd.com/read/28205258/simultaneous-quantification-of-antofloxacin-and-its-major-metabolite-in-human-urine-by-hplc-ms-ms-and-its-application-to-a-pharmacokinetic-study
#14
Yunsu Ma, Qianru Wang, Hongwen Zhang, Lijun Xie, Juan Chen, Mao Huang, Yun Liu, Yuanyuan Wang, Libin Wang, Luning Sun, Ning Ou
This study presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the simultaneous determination of antofloxacinin and its main metabolite-N-demethylated metabolite (N-DM) in human urine, ornidazole was used as the internal standard (IS). This was a clinical urine recovery study, in which 10 healthy Chinese volunteers were intravenously administered a single 200 mg antofloxacin hydrochloride. Compounds were extracted by albumen precipitation, after which, samples were isocratic eluted by a Poroshell 120 SB-C18 column, and were analysed using HPLC-MS/MS under electronic spray ionization (ESI) positive ion mode...
February 16, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/28202192/ordered-mesoporous-silica-functionalized-with-%C3%AE-cyclodextrin-derivative-for-stereoisomer-separation-of-flavanones-and-flavanone-glycosides-by-nano-liquid-chromatography-and-capillary-electrochromatography
#15
Mariana Silva, Damián Pérez-Quintanilla, Sonia Morante-Zarcero, Isabel Sierra, María Luisa Marina, Zeineb Aturki, Salvatore Fanali
In this paper a chiral stationary phase (CSP) was prepared by the immobilization of a β-CD derivative (3,5-dimethylphenylcarbamoylated β-CD) onto the surface of amino-functionalized spherical ordered mesoporous silica (denoted as SM) via a urea linkage using the Staudinger reaction. The CSP was packed into fused silica capillaries 100μm I.D. and evaluated by means of nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) using model compounds for the enantio- and the diastereomeric separation...
February 9, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28202180/chemical-structure-influence-on-napl-mixture-nonideality-evolution-rate-limited-dissolution-and-contaminant-mass-flux
#16
Mark C Padgett, Geoffrey R Tick, Kenneth C Carroll, William R Burke
The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions >0...
February 3, 2017: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28201853/antigenic-cross-reactivity-between-schistosoma-mansoni-and-peanut-a-role-for-cross-reactive-carbohydrate-determinants-ccds-and-implications-for-the-hygiene-hypothesis
#17
Joseph E Igetei, Marwa El-Faham, Susan Liddell, Michael J Doenhoff
The antigenic reactivity of constituents of Schistosoma mansoni and peanut (Arachis hypogaea) was investigated to determine whether identical antigenic epitopes possessed by both organisms provided a possible explanation for the negative correlation between chronic schistosome infection and atopy to allergens. Aqueous extracts of peanuts were probed in Western immunoblots with rabbit IgG antibodies raised against the egg, cercarial and adult worm stages of S. mansoni. Several molecules in the peanut extract were antigenically reactive with antibodies from the various rabbit anti-schistosome sera...
February 15, 2017: Immunology
https://www.readbyqxmd.com/read/28199916/isolation-of-four-phenolic-compounds-from-mangifera-indica-l-flowers-by-using-normal-phase-combined-with-elution-extrusion-two-step-high-speed-countercurrent-chromatography
#18
Nusrat Shaheen, Yanzhen Lu, Ping Geng, Qian Shao, Yun Wei
Two-step high speed countercurrent chromatography method, following normal phase and elution-extrusion mode of operation by using selected solvent systems, was introduced for phenolic compounds separation. Phenolic compounds including gallic acid, ethyl gallate, ethyl digallate and ellagic acid were separated from the ethanol extract of mango (Mangifera indica L.) flowers for the first time. In the first step, gallic acid of 3.7mg and ethyl gallate of 3.9mg with the purities of 98.87% and 99.55%, respectively, were isolated by using hexane-ethylacetate-methanol-water (4:6:4:6, v/v) in normal phase high speed countercurrent chromatography from 200mg of crude extract, while ethyl digallate and ellagic acid were collected in the form of mixture fraction...
January 15, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28199100/complexes-of-magnetic-nanoparticles-with-cellulose-nanocrystals-as-regenerable-highly-efficient-and-selective-platform-for-protein-separation
#19
Jiaqi Guo, Ilari Filpponen, Leena-Sisko Johansson, Pezhman Mohammadi, Mika Latikka, Markus B Linder, Robin H A Ras, Orlando J Rojas
We present an efficient approach to synthesize cellulose nanocrystal (CNC) hybrids with magnetically responsive Fe3O4 nanoparticles that were synthesized using the (Fe3+/Fe2+) co-precipitation. After TEMPO-catalyzed oxidation of CNC, carbodiimide (EDC/NHS) was used for coupling amine-containing iron oxide nanoparticles that were achieved by dopamine ligand exchange (NH2-Fe3O4 NPs). The as prepared hybrids (Fe3O4@CNC) were further complexed with Cu(II) ions to produce specific protein binding sites. The performance of magnetically responsive Cu-Fe3O4@CNC hybrid was assessed by selectively separating lysozyme from aqueous media...
February 15, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28198114/immunoaffinity-knockout-of-saponin-glycosides-from-asparagus-racemosus-to-assess-anti-lipid-peroxidation
#20
Churanya Onlom, Watoo Phrompittayarat, Waraporn Putalun, Neti Waranuch, Kornkanok Ingkaninan
INTRODUCTION: Asparagus racemosus Willd (Asparagaceae family), known as Shatavari, is important in Ayurveda and traditional Thai medicines. The saponin glycosides, shatavarin I and IV are major constituents in its roots and may be responsible for their actions including protection against lipid peroxidation and carcinogenesis. OBJECTIVE: To develop an immunoaffinity column for isolating compounds with structures related to shatavarin IV from crude extracts of A...
February 15, 2017: Phytochemical Analysis: PCA
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