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Mass spectrometry

Dai Long Vu, Karolína Ranglová, Jan Hájek, Pavel Hrouzek
Quantification of selenated amino-acids currently relies on methods employing inductively coupled plasma mass spectrometry (ICP-MS). Although very accurate, these methods do not allow the simultaneous determination of standard amino-acids, hampering the comparison of the content of selenated versus non-selenated species such as methionine (Met) and selenomethionine (SeMet). This paper reports two approaches for the simultaneous quantification of Met and SeMet. In the first approach, standard enzymatic hydrolysis employing Protease XIV was applied for the preparation of samples...
March 9, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Aimin Tan, John C Fanaras
LC-MS/MS has been the dominant analytical technology for quantitative bioanalysis of drugs and metabolites for more than two decades. Despite this, a very fundamental question like how much separation is required for LC-MS/MS quantitative bioanalysis of drugs and metabolites has not been adequately addressed. Some think that no or only very limited separation is necessary thanks to the unparalleled selectivity offered by tandem mass spectrometry. Others think that the more separation, the better, because of the potential detrimental impact of matrix effect (ion suppression or enhancement)...
March 14, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Zhaohui Qiu, Jie Peng, Lingli Mou, Xiao Li, Fanqi Meng, Peng Yu
Multidrug resistance (MDR) of tumors occurs when tumor cells exhibit reduced sensitivity to a large number of unrelated drugs. The molecular mechanism of MDR commonly involves overexpression of the plasma membrane drug efflux pump P-glycoprotein (P-gp). Overexpression of P-gp may be induced by the selection and/or adaptation of cells during exposure to chemotherapeutic drugs, referred to as acquired P-gp-mediated MDR. This study aimed to establish a P-gp quantification method by Ultra Performance Liquid Chromatography and Tandem Mass Spectrometry (UPLC-MS/MS) to better understand the regulation of P-gp expression and its relationship with the level of drug resistance...
March 8, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Wen-Ping Huang, Ting Tan, Zhi-Feng Li, Hui OuYang, Xu Xu, Bin Zhou, Yu-Lin Feng
The Chimonanthus nitens Oliv. leaf (CNOL). is a widely used traditional Chinese medicine (TCM) used for treating colds and influenza. In the present study, a comprehensive strategy integrating multiple chromatographic analysis and chemometric methods was firstly proposed for structural characterization and discrimination of CNOL from different geographical origins. It consists of three steps: Firstly, the ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) method was applied for comprehensive profiling of characterization constituents in CNOL by high-resolution diagnostic product ions/neutral loss filtering, and a total of 40 constituents were identified...
February 10, 2018: Journal of Pharmaceutical and Biomedical Analysis
Min Cheng, Guangming Zeng, Danlian Huang, Cui Lai, Yang Liu, Chen Zhang, Jia Wan, Liang Hu, Chengyun Zhou, Weiping Xiong
The presence of antibiotics in aquatic environments has attracted global concern. Fenton process is an attractive yet challenging method for antibiotics degradation, especially when such a reaction can be conducted at neutral pH values. In this study, a novel composite Fe/Co catalyst was synthesized via the modification of steel converter slag (SCS) by salicylic acid-methanol (SAM) and cobalt nitrate (Co(NO3 )2 ). The catalysts were characterized by N2 -Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS)...
March 10, 2018: Water Research
Lindsay Glicksberg, Sumandeep Rana, Sarah Kerrigan
PURPOSE: Synthetic cathinones are encountered in a variety of antemortem and postmortem forensic toxicology investigations. Earlier experimental studies using fortified urine have evaluated analyte, temperature and pH-dependent variables associated with their stability. The purpose of this study was to compare experimental findings with those obtained using authentic urine from cathinone users. METHODS: In this report we compare cathinone concentrations in 180 authentic unpreserved urine specimens, following known periods of refrigerated storage...
March 8, 2018: Forensic Science International
Chi Zhang, Peizhe Zhang, Hongxia Li, Lianhua Han, Lei Zhang, Lei Zhang, Xiangjun Yang
OBJECTIVES: Dabigatran etexilate is widely used for stroke prevention in the patients with atrial fibrillation. The anticoagulation activity of dabigatran is not necessary monitored in routine clinical practice. We aimed to study the effect of dabigatran on thrombin generation (TG) and coagulation assays in rabbit and human plasma. METHODS: Rabbits received different concentrations of dabigatran etexilate (5 mg/kg, 10 mg/kg). Patients with atrial fibrillation took 110 mg dabigatran etexilate twice daily...
March 15, 2018: Thrombosis Research
Lei Zhang, Xin Liu, Guimin Meng, Min Chi, Jingguang Li, Shuaixing Yin, Yunfeng Zhao, Yongning Wu
Several studies support a plausible association of human exposure to polychlorinated biphenyls (PCBs) with type 2 diabetes mellitus. However, little is known about the potential link between circulating PCBs levels in early pregnancy and development of gestational diabetes mellitus (GDM). Here, we conducted a prospective study with a nested case-control design to determine the association of PCB exposure in early pregnancy with GDM risk. Concentrations of selected so-called 'indicator PCBs' were determined in sera of women in the first trimester of pregnancy via gas chromatography - high resolution mass spectrometry...
March 17, 2018: Environment International
Alfonso Méndez-Bravo, Elvis Marian Cortazar-Murillo, Edgar Guevara-Avendaño, Oscar Ceballos-Luna, Benjamín Rodríguez-Haas, Ana L Kiel-Martínez, Orlando Hernández-Cristóbal, José A Guerrero-Analco, Frédérique Reverchon
Rhizobacteria associated with crops constitute an important source of potentially beneficial microorganisms with plant growth promoting activity or antagonistic effects against phytopathogens. In this study, we evaluated the plant growth promoting activity of 11 bacterial isolates that were obtained from the rhizosphere of healthy avocado trees and from that of avocado trees having survived root rot infestations. Seven bacterial isolates, belonging to the genera Bacillus, Pseudomonas and Arthrobacter, promoted in vitro growth of Arabidopsis thaliana...
2018: PloS One
Anne Küntzel, Peter Oertel, Sina Fischer, Andreas Bergmann, Phillip Trefz, Jochen Schubert, Wolfram Miekisch, Petra Reinhold, Heike Köhler
BACKGROUND: Species of Mycobacteriaceae cause serious zoonotic diseases in mammals, for example tuberculosis in humans, dogs, parrots, and elephants (caused by Mycobacterium tuberculosis) and in ruminants and humans (caused by M. bovis and M. caprae). Pulmonary diseases, lymphadenitis, skin diseases, and disseminated diseases can be caused by non-tuberculous mycobacteria (NTM). Diagnosis and differentiation among Mycobacterium species are currently done by culture isolation. The established diagnostic protocols comprise several steps that allow species identification...
2018: PloS One
Zheng Yan, Lan Wang, Jun Wang, Yanglan Tan, Dianzhen Yu, Xiaojiao Chang, Yingying Fan, Duoyong Zhao, Cheng Wang, Marthe De Boevre, Sarah De Saeger, Changpo Sun, Aibo Wu
The determination of zearalenone (ZEN) and its derivatives as biomarkers in animal tissues or organs plays an important role in mycotoxin monitoring and can promote effective exposure assessment. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of nine ZEN-like mycotoxins, including three glucuronides in different pig tissues (heart, liver, spleen and muscle) was developed and validated in this study. Tissue samples were extracted using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and clean-up procedure, and analyzed by LC-MS/MS in multiple reaction monitoring (MRM) mode...
March 20, 2018: Toxins
Alejandra M Wiedeman, Kyly C Whitfield, Kaitlin M March, Nancy N Chen, Hou Kroeun, Ly Sokhoing, Prak Sophonneary, Roger A Dyer, Zhaoming Xu, David D Kitts, Timothy J Green, Sheila M Innis, Susan I Barr
Choline has critical roles during periods of rapid growth and development, such as infancy. In human milk, choline is mostly present in water-soluble forms (free choline, phosphocholine, and glycerophosphocholine). It is thought that milk choline concentration is influenced by maternal choline intake, and the richest food sources for choline are of animal origin. Scarce information exists on milk choline from countries differing in animal-source food availability. In this secondary analysis of samples from previous trials, the concentrations of the water-soluble forms of choline were quantified by liquid chromatography-tandem mass spectrometry in mature milk samples collected from lactating women in Canada ( n = 301) and in Cambodia ( n = 67)...
March 20, 2018: Nutrients
Joelle Khairallah, Shima Sadeghi Ekbatan, Kebba Sabally, Michèle M Iskandar, Raza Hussain, Atef Nassar, Lekha Sleno, Laetitia Rodes, Satya Prakash, Danielle J Donnelly, Stan Kubow
A multistage human gastrointestinal model was used to digest a polyphenol-rich potato extract containing chlorogenic acid, caffeic acid, ferulic acid, and rutin as the primary polyphenols, to assess for their microbial biotransformation and to measure changes in antioxidant capacity in up to 24 h of digestion. The biotransformation of polyphenols was assessed by liquid chromatography-mass spectrometry. Antioxidant capacity was measured by the ferric reducing antioxidant power (FRAP) assay. Among the colonic reactors, parent (poly)phenols were detected in the ascending (AC), but not the transverse (TC) or descending (DC) colons...
March 20, 2018: Antioxidants (Basel, Switzerland)
Monther A Khanfar, Areej M Jaber, Murad A AlDamen, Raed A Al-Qawasmeh
A copper complex with square planar geometry, [(L)CuBr₂] ( 1 ), (L = N' -(furan-2-ylmethylene)adamantne-1-carbohydrazide) has been synthesized and characterized by Fourier transfer infrared (FTIR) spectroscopy, elemental analysis, mass spectrometry, and single crystal X-ray diffraction. The crystal of 1 is solved as monoclinic, space group P2₁/m with unit cell parameters: a = 10.8030(8), b = 6.6115(8), c = 12.1264(12) Å, β = 101.124(8)°, V = 849.84(15) ų, Z = 2, and R₁ = 0.0751 with wR₂ = 0.1581 (I > 2 σ)...
March 20, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Rei-Lin Kuo, Chi-Jene Chen, Ee-Hong Tam, Chung-Guei Huang, Li-Hsin Li, Zong-Hua Li, Pei-Chia Su, Hao-Ping Liu, Chih-Ching Wu
Influenza A virus infections can result in severe respiratory diseases. The H7N9 subtype of avian influenza A virus has been transmitted to humans and caused severe disease and death. Nonstructural protein 1 (NS1) of influenza A virus is a virulence determinant during viral infection. To elucidate the functions of the NS1 encoded by influenza A H7N9 virus (H7N9 NS1), interaction partners of H7N9 NS1 in human cells were identified with immunoprecipitation followed by SDS-PAGE coupled with liquid chromatography-tandem mass spectrometry (GeLC-MS/MS)...
March 20, 2018: Journal of Proteome Research
Salvador Martínez-Bartolomé, J Alberto Medina-Aunón, Miguel Ángel López-García, Carmen González-Tejedo, Gorka Prieto, Rosana Navajas, Emilio Salazar-Donate, Carolina Fernandez-Costa, John R Yates, Juan Pablo Albar
Mass spectrometry-based proteomics has evolved into a high-throughput technology where numerous large-scale datasets are generated from diverse analytical platforms. Furthermore, several scientific journals and funding agencies have emphasized the storage of proteomics data in public repositories to facilitate its evaluation, inspection and reanalysis. As a consequence, public proteomics data repositories are growing rapidly. However, tools are needed to integrate multiple proteomics datasets in order to compare different experimental features or to perform quality control analysis...
March 20, 2018: Journal of Proteome Research
Zewdu Hora, Solomon Zewdu Altaye, Abebe Jenberie Wubie, Jianke Li
The honeybee is one of the most valuable insect pollinators, which plays a key role in pollinating wild vegetation and agricultural crops, with significant contribution to world food production. Although honeybees have long been studied as model for social evolution, the molecular level of honeybee biology remained poorly understood until the year 2006. With the available honeybee genome sequence, technological advancements in protein separation, mass spectrometry, and bioinformatics, wide ranges of honeybee biology such as developmental biology, physiology, behavior, neurobiology, and immunology are explored to a new depth at molecular and biochemical levels...
March 20, 2018: Journal of Agricultural and Food Chemistry
Brittney Ann Klein, Béla Reiz, Ian Michael Robertson, Malcolm Irving, Liang Li, Yin-Biao Sun, Brian D Sykes
The development of calcium sensitizers for the treatment of systolic heart failure presents difficulties including judging the optimal efficacy and the specificity to target cardiac muscle. The thin filament is an attractive target since cardiac troponin-C (cTnC) is the site of calcium binding and the trigger for subsequent contraction. One widely studied calcium sensitizer is levosimendan. We have recently shown that when a covalent cTnC-levosimendan analog is exchanged into cardiac muscle cells, they become constitutively active, demonstrating the potency of a covalent complex...
March 20, 2018: Biochemistry
Dae Young Lee, Ju-Hyun Kim, Hyun Joo Shim, Hyeon-Uk Jeong, Hye Suk Lee
The objective of this study was to determine the absorption, excretion, and metabolism of a novel, oral antihyperglycemic drug, evogliptin, in male rats and dogs. Plasma, urine, feces, and expired air samples were collected after a single oral dose administration of [14 C]evogliptin, samples were analyzed by measuring overall radioactivity levels using high-performance liquid chromatography (HPLC), and radioactivity levels were measured by utilizing LC-tandem mass spectrometry (LC-MS/MS). The total amounts of radioactivity excreted in urine, feces, and expired air up to 168 h after administration of [14 C]evogliptin tartrate to rats (30 mg evogliptin/kg) and dogs (10 mg evogliptin/kg) were 96...
March 20, 2018: Journal of Toxicology and Environmental Health. Part A
Laura Pogliani, Sara Baldelli, Dario Cattaneo, Paola Pileri, Emilio Clementi, Irene Cetin, M D Gianvincenzo Zuccotti
OBJECTIVE: Selective serotonin reuptake inhibitors are commonly used for the treatment of pregnancy-related and postnatal depression. However, only a few studies have evaluated the passage of these drugs into human milk, often with conflicting results. Here, we sought to evaluate the passage of selective serotonin reuptake inhibitors into human milk in the first days after delivery and their potential association with neonatal outcomes. STUDY DESIGN: The passage of selective serotonin reuptake inhibitors into human milk was expressed both as percentage of milk-to-plasma ratio of drug concentrations and as the relative infant dose...
March 20, 2018: Journal of Maternal-fetal & Neonatal Medicine
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