EarlyView Articles
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High‐permittivity solid ceramic resonators for high‐field human MRI
Published: Jul 4, 2013
Author(s): S. A. Aussenhofer, A. G. Webb
Journal: NMR in Biomedicine
The properties of a ceramic‐based annular dielectric resonator designed for 7 T MRI have been examined. Electromagnetic simulations and experimentally determined modal frequencies agree to within ~1%. The dependence of the resonance frequency of the degenerate quadrature HEM11 modes on hole diameter and shield diameter was also investigated. The constructed coil, with a 2.5 cm diameter hole, had an unloaded Q value of 400, which was...
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High‐resolution NMR spectroscopy of human body fluids and tissues in relation to prostate cancer
Published: Jul 4, 2013
Author(s): Virendra Kumar, Durgesh K. Dwivedi, Naranamangalam R. Jagannathan
Journal: NMR in Biomedicine
High‐resolution NMR spectroscopic studies of prostate tissue extracts, prostatic fluid, seminal fluid, serum and urine can be used for the detection of prostate cancer, based on the differences in their metabolic profiles. Useful diagnostic information is obtained by the detection or quantification of as many metabolites as possible and comparison with normal samples. Only a few studies have shown the potential of high‐resolution in vitro...
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Bayesian estimation of membership uncertainty in model‐based clustering
Published: Jul 4, 2013
Author(s): Liyuan Chen, Steven D. Brown
Journal: Journal of Chemometrics
We report the use of a cluster analysis method based on a multivariate mixture model, known as model‐based clustering, for overcoming the limitations of hierarchical clustering and relocation clustering. Unlike traditional clustering methods in which clusters are formed on the basis of intercluster distances, model‐based clustering classifies observations on the basis of probability estimated from Gaussian mixture modeling, and its...
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Modification of cysteine residues by cyclopentenone prostaglandins: Interplay with redox regulation of protein function
Published: Jul 1, 2013
Author(s): Clara L. Oeste, Dolores Pérez‐Sala
Journal: Mass Spectrometry Reviews
Abstract Cyclopentenone prostaglandins (cyPG) are endogenous lipid mediators involved in the resolution of inflammation and the regulation of cell proliferation and cellular redox status. Upon exogenous administration they have shown beneficial effects in models of inflammation and tissue injury, as well as potential antitumoral actions, which have raised a considerable interest in their study for the...
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Pharmacokinetic properties of isradipine after single‐dose and multiple‐dose oral administration in Chinese volunteers: a randomized, open‐label, parallel‐group phase I study
Published: Jul 1, 2013
Author(s): Yanran Wang, Zhaohui Jin, Zhijun Wang, Xuehua Jiang, Ling Wang
Journal: Biomedical Chromatography
ABSTRACT Isradipine could be used for the treatment of high blood pressure or Parkinsonism, yet the study on pharmacokinetics (PK) of isradipine is lacking in the Chinese population. The current study aims to assess the dose proportionality, pharmacokinetics and gender effect of isradipine following oral single and multiple doses in Chinese subjects. A randomized, open‐label, parallel‐group trial was conducted in 30 healthy Chinese...
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Quantitative determination of d‐ and l‐threo enantiomers of methylphenidate in brain tissue by liquid chromatography–mass spectrometry
Published: Jul 1, 2013
Author(s): Carolyn C. Combs, Erin L. Hankins, Cara L. Copeland, Stacy D. Brown, Brooks B. Pond
Journal: Biomedical Chromatography
ABSTRACT Methylphenidate, a psychostimulant used for the treatment of attention deficit hyperactivity disorder and narcolepsy, is administered as a 50:50 racemic mixture, despite the fact that d‐methylphenidate has been shown to have greater pharmacologic activity. This paper presents a validated LC‐MS/MS approach to separation and quantification of methylphenidate enantiomers using a vancomycin column and triethylammonium acetate...
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Simultaneous quantitative analyses of indole and oxindole alkaloids of Uncaria Hook in rat plasma and brain after oral administration of the traditional Japanese medicine Yokukansan using high‐performance liquid chromatography with tandem mass spectrometr
Published: Jul 1, 2013
Author(s): Hirotaka Kushida, Miwako Fukutake, Masahiro Tabuchi, Takao Katsuhara, Hiroaki Nishimura, Yasushi Ikarashi, Masanao Kanitani, Yoshio Kase
Journal: Biomedical Chromatography
ABSTRACT Uncaria Hook (UH) alkaloids are involved in the beneficial effects of Yokukansan. However, the pharmacokinetics of UH alkaloids after oral administration of Yokukansan has not yet been sufficiently investigated. Therefore, we developed and validated a sensitive and specific high‐performance liquid chromatography with tandem mass spectrometry (LC/MS/MS) method for the simultaneous quantitation of seven UH alkaloids...
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Screening and determination for potential α ‐glucosidase inhibitory constituents from Dalbergia odorifera T. Chen using ultrafiltration‐LC/ESI‐MS n
Published: Jul 1, 2013
Author(s): Chunfang Zhao, Yongqiang Liu, Dengli Cong, Hui Zhang, Jiajia Yu, Ying Jiang, Xiuyue Cui, Jiaming Sun
Journal: Biomedical Chromatography
ABSTRACT In the present study, it was demonstrated that ethyl acetate soluble fraction partitioned from heartwood of Dalbergia odorifera T. Chen (HEF) had a remarkable inhibitory effect on α‐glucosidase. Therefore HEF was selected as a starting material for screening the potential α‐glucosidase inhibitors using ultrafiltration liquid chromatography/mass spectrometry (UF‐LC/MS). Twenty‐six compounds were identified with analysis of LC/MS. UF assay indicated...
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Characterization and quantification of 10‐hydroxycamptothecine in Camptotheca acuminate and its medicinal preparation by liquid chromatography–ion trap mass spectrometry
Published: Jul 1, 2013
Author(s): Qinhua Chen, Guangmin Pan, Lin Xiong, Hongsheng He, Hangdong Yang
Journal: Biomedical Chromatography
ABSTRACT A rapid and sensitive method for the identification and quantification of 10‐hydroxycamptothecine (HCPT) in Camptotheca acuminata Decne is described. The HCPT standard solution was directly infused into the ion trap mass spectrometers (IT/MS) for collecting the MSn spectra. The electrospray ionization (ESI) mass spectral fragmentation pathway of HCPT was proposed and the ESI‐MSn fragmentation behavior of HCPT was deduced in detail. The major...
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Quantitative analysis of heavy elements and semi‐quantitative evaluation of heavy mineral compositions of sediments in Japan for construction of a forensic soil database using synchrotron radiation X‐ray analyses
Published: Jun 28, 2013
Author(s): Izumi Nakai, Shunsuke Furuya, Willy Bong, Yoshinari Abe, Keiichi Osaka, Takuya Matsumoto, Masayoshi Itou, Atsuyuki Ohta, Toshio Ninomiya
Journal: X-Ray Spectrometry
We have started to construct a nationwide forensic soil sediment database for Japan, based on the heavy mineral and trace heavy element compositions of stream sediments collected at 3024 points across Japan. The data were measured by high‐resolution synchrotron radiation X‐ray powder diffraction (SR‐XRD) and high‐energy SR X‐ray fluorescence analysis (XRF) using the SR source of SPring‐8, the SR radiation facility in Japan. The automated...
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High‐resolution imaging of magnetisation transfer and nuclear Overhauser effect in the human visual cortex at 7 T
Published: Jun 26, 2013
Author(s): Olivier Mougin, Matthew Clemence, Andrew Peters, Alain Pitiot, Penny Gowland
Journal: NMR in Biomedicine
The aim of this study was to optimise a pulse sequence for high‐resolution imaging sensitive to the effects of conventional macromolecular magnetisation transfer (MTm) and nuclear Overhauser enhancement (NOE), and to use it to investigate variations in these parameters across the cerebral cortex. A high‐spatial‐resolution magnetisation transfer‐prepared turbo field echo (MT‐TFE) sequence was designed to have high sensitivity to MTm and...
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Salbutamol extraction from urine and its stability in different solutions: identification of methylation products and validation of a quantitative analytical method
Published: Jun 26, 2013
Author(s): Bruno Carius Garrido, Mayra Leal Chrisóstomo Silva, Ricardo Moreira Borges, Monica Costa Padilha, Francisco Radler Aquino Neto
Journal: Biomedical Chromatography
ABSTRACT Salbutamol is commonly used in asthma treatment, being considered a short‐effect bronchodilator. This drug poses special interest in certain fields of chemical analysis, such as food, clinical and doping analyses, in which it needs to be analyzed with quantitative precision and accuracy. Salbutamol, however, is known to degrade under certain conditions and this is critical if quantitative results must be generated. The...
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In vivo MRI analysis of depth‐dependent ultrastructure in human knee cartilage at 7 T
Published: Jun 25, 2013
Author(s): Nikita Garnov, Wilfried Gründer, Gregor Thörmer, Robert Trampel, Robert Turner, Thomas Kahn, Harald Busse
Journal: NMR in Biomedicine
Signal intensities of T2‐weighted magnetic resonance images depend on the local fiber arrangement in hyaline cartilage. The aims of this study were to determine whether angle‐sensitive MRI at 7 T can be used to quantify the cartilage ultrastructure of the knee in vivo and to assess potential differences with age. Ten younger (21–30 ) and ten older (55–76 years old) healthy volunteers were imaged with a T2‐weighted spin‐echo...
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Determination of the stress biomarker corticosterone in serum of tumor‐bearing mice by surrogate‐based liquid chromatography–tandem mass spectrometry
Published: Jun 25, 2013
Author(s): Lei Kang, Tao Jiang, Xinxing Ge, Liang Peng, Ying Xie, Xin Luan, Huafang Li, Zhengxing Rong, Hong Qi, Hongzhuan Chen
Journal: Biomedical Chromatography
ABSTRACT A simple, robust and specific liquid chromatography tandem mass spectrometry (LC‐MS/MS) method was developed and validated to determine the concentration of corticosterone (Cort) which is usually regarded as a stress biomarker in mouse serum. Since Cort is an endogenous hormone, a ‘surrogate analyte’ strategy was adopted using the stable isotope‐deuterated corticosterone as a surrogate of the authentic analyte to generate...
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Using microbubbles as an MRI contrast agent for the measurement of cerebral blood volume
Published: Jun 24, 2013
Author(s): Shin‐Lei Peng, Fu‐Nien Wang, Chung‐Hsin Wang, Hsu‐Hsia Peng, Chih‐Tien Lu, Chih‐Kuang Yeh
Journal: NMR in Biomedicine
The susceptibility differences at the gas–liquid interface of microbubbles (MBs) allow their use as an intravascular susceptibility contrast agent for in vivo MRI. However, the characteristics of MBs are very different from those of the standard gadolinium‐diethylenetriaminepentaacetic acid (Gd‐DPTA) contrast agent, including the size distribution and hemodynamic properties, which could influence MRI outcomes. Here, we investigate...
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Enhancing the [ 13 C]bicarbonate signal in cardiac hyperpolarized [1‐ 13 C]pyruvate MRS studies by infusion of glucose, insulin and potassium
Published: Jun 24, 2013
Author(s): Mette Hauge Lauritzen, Christoffer Laustsen, Sadia Asghar Butt, Peter Magnusson, Lise Vejby Søgaard, Jan Henrik Ardenkjær‐Larsen, Per Åkeson, C. Laustsen, J. H. Ardenkjær‐Larsen, J. H. Ardenkjær‐Larsen
Journal: NMR in Biomedicine
A change in myocardial metabolism is a known effect of several diseases. MRS with hyperpolarized 13C‐labelled pyruvate is a technique capable of detecting changes in myocardial pyruvate metabolism, and has proven to be useful for the evaluation of myocardial ischaemia in vivo. However, during fasting, the myocardial glucose oxidation is low and the fatty acid oxidation (β‐oxidation) is high, which complicates the interpretation of pyruvate metabolism...
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Characterization of synthetic routes to ‘Bromo‐DragonFLY’ and benzodifuranyl isopropylamine homologues utilizing ketone intermediates. Part 1: Synthesis of ketone precursors
Published: Jun 24, 2013
Author(s): Richard E. O'Connor, John J. Keating
Journal: Drug Testing and Analysis
Bromo‐DragonFLY (BDF) and many of its analogues are misused as recreational drugs due to their potency as psychoactive substances. To date, none of the published routes to these designer amphetamines have exploited a ketone intermediate. It is well known that benzyl methyl ketone (BMK) can be employed as a precursor in the synthesis of amphetamine. Similarly, it is reasonable to assume that ketone precursors may potentially be utilized in...
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Pharmacokinetics of methyl salicylate‐2‐ O‐β ‐D‐lactoside, a novel salicylic acid analog isolated from Gaultheria yunnanensis ,in dogs
Published: Jun 24, 2013
Author(s): Dan Zhang, Xiaowei Ma, Wenyu Xin, Chao Huang, Weiku Zhang, Tiantai Zhang, Guanhua Du
Journal: Biomedical Chromatography
ABSTRACT Methyl salicylate‐2‐O‐β‐D‐lactoside (MSL), a natural salicylate derivative of Gaultheria yunnanensis (Franch.) Rehder (G. yunnanensis), has been shown to provide a beneficial anti‐inflammatory effect in animal models. Studies on the pharmacokinetics and bioavailability of MSL can provide both a substantial foundation for understanding its mechanism and empirical evidence to support its use in clinical practice. A simple and sensitive...
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Development and validation of a sensitive LC‐MS/MS‐ESI method for the determination of ivabradine in human plasma: application to a pharmacokinetic study
Published: Jun 24, 2013
Author(s): Juanjuan Jiang, Lei Tian, Yiling Huang, Yishi Li
Journal: Biomedical Chromatography
ABSTRACT A sensitive, rapid assay method for estimating ivabradine in human plasma has been developed and validated using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The procedure involved extraction of ivabradine and the internal standard (IS) from human plasma by solid‐phase extraction. Chromatographic separation was achieved using an isocratic mobile phase (0.1%...
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Development and validation of an RP‐HPLC method for the quantitation of Orteronel (TAK‐700), a CYP17A1 enzyme inhibitor, in rat plasma and its application to a pharmacokinetic study
Published: Jun 21, 2013
Author(s): Avinash Kumar, S Vijay Kumar, Sandip Gurav, Mohd Zainuddin, Purushottam Dewang, Raghava Reddy Kethiri, Sriram Rajagopal, Ramesh Mullangi
Journal: Biomedical Chromatography
ABSTRACT A novel, simple, specific, sensitive and reproducible high‐performance liquid chromatography assay method has been developed and validated for the estimation of Orteronel in rat plasma. The bioanalytical procedure involves extraction of Orteronel and phenacetin (internal standard) from rat plasma with a simple liquid–liquid extraction process. The chromatographic analysis was performed on a Waters Alliance system using a...
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