EarlyView Articles

Underestimation of rat serum vancomycin concentrations measured by an enzyme‐multiplied immunoassay technique and the strategy for its avoidance

Published: Aug 13, 2013

Author(s): Hiroki Konishi, Ikumi Iga, Katsuhito Nagai

Journal: Drug Testing and Analysis

An enzyme‐multiplied immunoassay technique (EMIT) has been widely adopted for the measurement of serum concentrations of vancomycin (VCM) in clinical practice. Because of the growing demand for its application to fundamental pharmacokinetic studies, we examined whether VCM concentrations in rat serum were accurately measured by EMIT. It was found that measured values of known amounts of VCM spiked to rat serum were markedly underestimated...

The role of metabolic imaging in radiation therapy of prostate cancer

Published: Aug 12, 2013

Author(s): V. Y. Zhang, A. Westphalen, L. Delos Santos, Z. L. Tabatabai, K. Shinohara, D. B. Vigneron, J. Kurhanewicz

Journal: NMR in Biomedicine

The goal of this study was to correlate prostatic metabolite concentrations from snap‐frozen patient biopsies of recurrent cancer after failed radiation therapy with histopathological findings, including Ki‐67 immunohistochemistry and pathologic grade, in order to identify quantitative metabolic biomarkers that predict for residual aggressive versus indolent cancer. A total of 124 snap‐frozen transrectal ultrasound (TRUS)‐guided biopsies...

Quantitative magnetization transfer MRI of desmoplasia in pancreatic ductal adenocarcinoma xenografts

Published: Aug 12, 2013

Author(s): Weiguo Li, Zhuoli Zhang, Jodi Nicolai, Guang‐Yu Yang, Reed A. Omary, Andrew C. Larson

Journal: NMR in Biomedicine

Quantitative assessment of desmoplasia in pancreatic ductal adenocarcinoma (PDAC) may be critical for staging or prediction of response to therapy. We performed quantitative magnetization transfer (qMT) MRI measurements in 18 mouse xenograft tumors generated from three PDAC cell lines. The qMT parameter bound proton fraction (BPF) was found to be significantly higher in tumors grown using the BxPC‐3 cell line (5.31 ± 0.87, mean ± standard...

Effect of taxane‐based neoadjuvant chemotherapy on fibroglandular tissue volume and percent breast density in the contralateral normal breast evaluated by 3T MR

Published: Aug 12, 2013

Author(s): Jeon‐Hor Chen, Wei‐Fan Pan, Julian Kao, Jocelyn Lu, Li‐Kuang Chen, Chih‐Chen Kuo, Chih‐Kai Chang, Wen‐Pin Chen, Christine E. McLaren, Shadfar Bahri, Rita S. Mehta, Min‐Ying Su

Journal: NMR in Biomedicine

The aim of this study was to evaluate the change of breast density in the normal breast of patients receiving neoadjuvant chemotherapy (NAC). Forty‐four breast cancer patients were studied. MRI acquisition was performed before treatment (baseline), and 4 and 12 weeks after treatment. A computer‐algorithm‐based program was used to segment breast tissue and calculate breast volume (BV), fibroglandular tissue volume (FV), and percent density...

Diffusion tensor imaging detects treatment effects of FTY720 in experimental autoimmune encephalomyelitis mice

Published: Aug 12, 2013

Author(s): Xiaojie Wang, Joan K. Brieland, Joong H. Kim, Ying‐Jr Chen, Janet O'Neal, Shawn P. O'Neil, Tsang‐Wei Tu, Kathryn Trinkaus, Sheng‐Kwei Song

Journal: NMR in Biomedicine

Fingolimod (FTY720) is an orally available sphingosine‐1‐phosphate (S1P) receptor modulator reducing relapse frequency in patients with relapsing–remitting multiple sclerosis (RRMS). In addition to immunosuppression, neuronal protection by FTY720 has also been suggested, but remains controversial. Axial and radial diffusivities derived from in vivo diffusion tensor imaging (DTI) were employed as noninvasive biomarkers of axonal injury and...

Determination of newly synthesized lipoic acid–niacin dimer in rat plasma by UPLC/electrospray ionization tandem mass spectrometry: assay development, validation and application to a pharmacokinetic study

Published: Aug 12, 2013

Author(s): Xiao Chen, Jingwen Gao, Yiming Jiang, Ping Huang, Yuhui Xie, Rongbiao Pi, Shuzhen Zhu, Meicun Yao

Journal: Biomedical Chromatography

ABSTRACT A simple, sensitive and specific ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC‐MS/MS) method was developed to determine the newly synthesized compound lipoic acid–niacin dimer (N2L) in plasma. Plasma samples were precipitated by methanol using tetrahydropalmatine as internal standard. Chromatographic separation was achieved on an Acquity BEH C18 (2.1 × 50 mm i.d., 1.7 µm) column; the mobile phase contains...

The impact of blood on liver metabolite profiling – a combined metabolomic and proteomic approach

Published: Aug 12, 2013

Author(s): Saray Ly‐Verdú, Alexander Schaefer, Melanie Kahle, Thomas Groeger, Susanne Neschen, Jose M. Arteaga‐Salas, Marius Ueffing, Martin Hrabe Angelis, Ralf Zimmermann

Journal: Biomedical Chromatography

ABSTRACT Metabolomics has entered the well‐established omic sciences as it is an indispensable information resource to achieve a global picture of biological systems. The aim of the present study was to estimate the influence of blood removal from mice liver as part of sample preparation for metabolomic and proteomic studies. For this purpose, perfused mice liver tissue (i.e. with blood removed) and unperfused mice liver tissue ...

Report on the Third International Conference on X‐ray analysis, 20–24 August 2012, Ulaanbaatar, Mongolia

Published: Aug 10, 2013

Author(s): A. Revenko, P. Zuzaan, S. Davaa

Journal: X-Ray Spectrometry

Optimizing FEG‐SEM combined with an SDD EDX system for automated GSR analysis

Published: Aug 10, 2013

Author(s): Elad S. Izraeli, Tsadok Tsach, Nadav Levin

Journal: X-Ray Spectrometry

Gunshot residue (GSR) analysis by scanning electron microscopy/energy dispersive x‐ray spectrometry (SEM/EDX) is routinely performed in forensic science laboratories. At the end of 2011, a field emission gun (FEG)‐SEM was installed at the authors' laboratory for this type of examination. Following the installation of the FEG‐SEM, an extensive process was conducted, in order to determine the optimal operating parameters of this instrument...

Effect of vibration–rotation coupling on simultaneous extraction of temperature and species concentration from vibrational CARS spectra of hot gases

Published: Aug 7, 2013

Author(s): Michele Marrocco

Journal: Journal of Raman Spectroscopy

The coupling between vibration and rotation in light molecules changes the strength of the Raman response. From this standpoint, we consider high‐temperature molecular spectra obtained by means of coherent anti‐Stokes Raman scattering (CARS), whose spectral intensity is useful to extract thermometric information and species concentrations for applications in combustion science. In this context and unlike other studies on the subject that...

Clustering of variables in regression analysis: a comparative study between different algorithms

Published: Aug 7, 2013

Author(s): Bahram Hemmateenejad, Sadegh Karimi, Nabiollah Mobaraki

Journal: Journal of Chemometrics

We have recently suggested using clustering of variables (CLoVA) based on unsupervised pattern recognition for partitioning variables into informative and redundant ones. Because data clustering plays a central role in CLoVA, in the present study, we compared the efficiency of different clustering methods including the Kohonen self‐organizing map (SOM), principal component analysis, fuzzy c‐means clustering, K‐means clustering, and...

Genetic algorithm for CoMFA setting optimization: 3D‐QSAR study on α‐aminosuberic acid derivatives as anti‐cancer compounds

Published: Aug 6, 2013

Author(s): S. Ebrahimi, G. Azimi, Y. Akhlaghi, M. Kompany‐Zareh

Journal: Journal of Chemometrics

In most three‐dimensional quantitative structure–activity relationship studies, default SYBYL parameters for comparative molecular field analysis (CoMFA) have been used to derive the models. In this work, a genetic algorithm has been employed for the first time to select the best set of parameters. Three‐dimensional quantitative structure–activity relationship analysis of a set of 33 analogues of α‐aminosuberic acid as a new generation of...

Detection of small interfering RNA (siRNA) by mass spectrometry procedures in doping controls

Published: Aug 5, 2013

Author(s): Andreas Thomas, Katja Walpurgis, Philippe Delahaut, Maxie Kohler, Wilhelm Schänzer, Mario Thevis

Journal: Drug Testing and Analysis

Uncovering manipulation of athletic performance via small interfering (si)RNA is an emerging field in sports drug testing. Due to the potential to principally knock down every target gene in the organism by means of the RNA interference pathway, this facet of gene doping has become a realistic scenario. In the present study, two distinct model siRNAs comprising 21 nucleotides were designed as double strands which were perfect counterparts...

Development and optimization of on‐line 2‐dimensional chromatographic approaches for eliminating matrix effects and improving bioanalysis of peptides in human plasma using UHPLC‐MS/MS

Published: Aug 5, 2013

Author(s): Omnia A. Ismaiel, Rand G. Jenkins

Journal: Drug Testing and Analysis

Online 2‐dimensional chromatographic approaches for eliminating matrix effects and optimizing bioanalysis of peptides using ultra‐high performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS) were studied. Three therapeutic peptides (octreotide, desmopressin, and vasopressin) were selected as model analytes. Human plasma was precipitated with acetonitrile; peptides were analyzed on C8, C18, Phenyl and HILIC ACQUITY UPLC...

LC‐MS/MS method for the determination of agomelatine in human plasma and its application to a pharmacokinetic study

Published: Aug 5, 2013

Author(s): Xiaolin Wang, Dan Zhang, Man Liu, Hongna Zhao, Aihua Du, Lingjie Meng, Huichen Liu

Journal: Biomedical Chromatography

ABSTRACT A sensitive and selective LC‐MS/MS method for the determination of agomelatine in human plasma was developed and validated. After simple liquid–liquid extraction, the analytes were separated on a Zorbax SB‐C18 column (150 × 2.1 mm i.d., 5 µm) with an isocratic mobile phase consisting of 5 mm ammonium acetate solution (containing 0.1% formic acid) and methanol (30:70, v/v) at a flow‐rate of 0.3 mL/min. The MS acquisition was performed...

Multivariate variographic versus bilinear data modeling

Published: Aug 2, 2013

Author(s): Pentti Minkkinen, Kim Harry Esbensen

Journal: Journal of Chemometrics

Two contrasting multivariate data sets (a process data series vs. a 1‐D geochemical soil profile) are analyzed to illustrate the benefits of using bilinear projection scores for variographic characterization instead of using individual variables. By using absolute variograms on a validated number of component scores, it is possible to make a combined multivariate chemometrics–variogram characterization of heterogeneous processes and...

Visualization and establishment of partial uniqueness and uniqueness rules in parallel factor analysis

Published: Aug 2, 2013

Author(s): Nematollah Omidikia, Hamid Abdollahi, Mohsen Kompany‐Zareh

Journal: Journal of Chemometrics

Parallel factor analysis (PARAFAC) is believed to be one of the most widely used multiway curve resolution techniques. The superiority of PARAFAC is due to its uniqueness property that is provided under mild assumptions. Unambiguously recovered chemically and physically meaningful profiles by PARAFAC are reliable for quantitative and qualitative application. The essential uniqueness condition of PARAFAC breaks totally or partially in data...

In vivo investigation of cardiac metabolism in the rat using MRS of hyperpolarized [1‐ ¹³ C] and [2‐ ¹³ C]pyruvate

Published: Jul 31, 2013

Author(s): Sonal Josan, Jae Mo Park, Ralph Hurd, Yi‐Fen Yen, Adolf Pfefferbaum, Daniel Spielman, Dirk Mayer

Journal: NMR in Biomedicine

Hyperpolarized 13C MRS allows the in vivo assessment of pyruvate dehydrogenase complex (PDC) flux, which converts pyruvate to acetyl‐coenzyme A (acetyl‐CoA). [1‐13C]pyruvate has been used to measure changes in cardiac PDC flux, with demonstrated increase in 13C‐bicarbonate production after dichloroacetate (DCA) administration. With [1‐13C]pyruvate, the 13C label is released as 13CO2/13C‐bicarbonate, and, hence, does not allow us to follow the fate of acetyl‐CoA. Pyruvate...

Multidimensional MR spectroscopic imaging of prostate cancer in vivo

Published: Jul 31, 2013

Author(s): M. Albert Thomas, Rajakumar Nagarajan, Amir Huda, Daniel Margolis, Manoj K. Sarma, Ke Sheng, Robert E. Reiter, Steven S. Raman

Journal: NMR in Biomedicine

Prostate cancer (PCa) is the second most common type of cancer among men in the United States. A major limitation in the management of PCa is an inability to distinguish, early on, cancers that will progress and become life threatening. One‐dimensional (1D) proton (1H) MRS of the prostate provides metabolic information such as levels of choline (Ch), creatine (Cr), citrate (Cit), and spermine (Spm) that can be used to detect and diagnose...

Discrimination of cathinone regioisomers, sold as ‘legal highs’, by Raman spectroscopy

Published: Jul 30, 2013

Author(s): R. Christie, E. Horan, J. Fox, C. O'Donnell, H. J. Byrne, S. McDermott, J. Power, P. Kavanagh

Journal: Drug Testing and Analysis

The discrimination of a cross section of cathinone regioisomers, sold as ‘legal highs’, using Raman spectroscopy, is reported here. Mephedrone and flephedrone were identified in ‘legal high’ products sold in Irish head shops, and their 2, 3 and 4‐isomers were synthesized as reference standards. The 3,4‐methylenedioxy substituted cathinones, methylone, butylone and methylenedioxypyrovalerone (MDPV), were also identified in ‘legal highs’...