EarlyView Articles

Identification and characterization of human UDP‐glucuronosyltransferases responsible for the in vitro glucuronidation of bergenin

Published: Sep 2, 2013

Author(s): Haojing Song, Jin Wang, Rui Zhang, Xiaoyan Liu, Guiyan Yuan, Chunmin Wei, Benjie Wang, Ruichen Guo

Journal: Biomedical Chromatography

ABSTRACT Glucuronidation plays critical role in the elimination of bergenin; however the metabolic mechanism of UDP‐glucuronosyltransferases (UGTs) in the process remains to be investigated. In this study, the kinetics of bergenin glucuronidation by pooled human liver microsomes (HLMs) and 12 recombinat UGT isozymes were investigated. The glucuronidation of bergenin can be shown in HLMs with a Km value of 231.62 ± 14.08 µm and a...

Simultaneous HPLC determination of ergosterol and 22,23‐dihydroergosterol in Flammulina velutipes sterol‐loaded microemulsion

Published: Sep 2, 2013

Author(s): Shanshan Tong, Hui Zhong, Chengxue Yi, Xia Cao, Caleb Kesse Firempong, Qianfeng Zheng, Yingshu Feng, Jiangnan Yu, Ximing Xu

Journal: Biomedical Chromatography

ABSTRACT An efficient HPLC method was developed and validated for the simultaneous determination of ergosterol and 22,23‐dihydroergosterol in Flammulina velutipes sterol‐loaded microemulsions (FVSMs). The different chromatographic conditions for in vitro and in vivo determinations were investigated, with the application examined by tissue distribution. Chromatographic separation was achieved on an Inertsil ODS‐SP (250 × 4.6 mm, 5 µm) analytical...

Prostate MR: current status, challenges and future directions

Published: Aug 30, 2013

Author(s): Naranamangalam R. Jagannathan

Journal: NMR in Biomedicine

Assessment of diffusion parameters by intravoxel incoherent motion MRI in head and neck squamous cell carcinoma

Published: Aug 30, 2013

Author(s): Simona Marzi, Francesca Piludu, Antonello Vidiri

Journal: NMR in Biomedicine

The objectives of this study were to assess the diffusion parameters derived from intravoxel incoherent motion (IVIM) MRI in head and neck squamous cell carcinoma (HNSCC) and to investigate the agreement between different methods of tumor delineation and two numerical methods to extract the perfusion fraction f. Thirty‐seven untreated patients with histopathologically confirmed primary HNSCC were included retrospectively in the study. The...

Intolerability of cobalt salt as erythropoietic agent

Published: Aug 30, 2013

Author(s): Bastian Ebert, Wolfgang Jelkmann

Journal: Drug Testing and Analysis

Unfair athletes seek ways to stimulate erythropoiesis, because the mass of haemoglobin is a critical factor in aerobic sports. Here, the potential misuse of cobalt deserves special attention. Cobalt ions (Co2+) stabilize the hypoxia‐inducible transcription factors (HIFs) that increase the expression of the erythropoietin (Epo) gene. Co2+ is orally active, easy to obtain, and inexpensive. However, its intake can bear risks to health. To elaborate this...

Q‐ball imaging with PROPELLER EPI acquisition

Published: Aug 29, 2013

Author(s): Ming‐Chung Chou, Teng‐Yi Huang, Hsiao‐Wen Chung, Tsyh‐Jyi Hsieh, Hing‐Chiu Chang, Cheng‐Yu Chen

Journal: NMR in Biomedicine

Q‐ball imaging (QBI) is an imaging technique that is capable of resolving intravoxel fiber crossings; however, the signal readout based on echo‐planar imaging (EPI) introduces geometric distortions in the presence of susceptibility gradients. This study proposes an imaging technique that reduces susceptibility distortions in QBI by short‐axis PROPELLER EPI acquisition. Conventional QBI and PROPELLER QBI data were acquired from two 3T MR...

Comparative evaluation of brain neurometabolites and DTI indices following whole body and cranial irradiation: a magnetic resonance imaging and spectroscopy study

Published: Aug 29, 2013

Author(s): Mamta Gupta, Poonam Rana, Richa Trivedi, B. S. Hemanth Kumar, Ahmad Raza Khan, Ravi Soni, R. K. S. Rathore, Subash Khushu

Journal: NMR in Biomedicine

Understanding early differential response of brain during whole body radiation or cranial radiation exposure is of significant importance for better injury management during accidental or intentional exposure to ionizing radiation. We investigated the early microstructural and metabolic profiles using in vivo diffusion tensor imaging (DTI) and proton magnetic resonance spectroscopy (1H MRS) following whole body and cranial radiation exposure of 8 Gy...

Determination of the appropriate b value and number of gradient directions for high‐angular‐resolution diffusion‐weighted imaging

Published: Aug 29, 2013

Author(s): J.‐Donald Tournier, Fernando Calamante, Alan Connelly

Journal: NMR in Biomedicine

High‐angular‐resolution diffusion‐weighted imaging (HARDI) is one of the most common MRI acquisition schemes for use with higher order models of diffusion. However, the optimal b value and number of diffusion‐weighted (DW) directions for HARDI are still undetermined, primarily as a result of the large number of available reconstruction methods and corresponding parameters, making it impossible to identify a single criterion by which to...

2D Raman spectroscopy study of dolomite and cyanobacterial extracellular polymeric substances from Khor Al‐Adaid sabkha (Qatar)

Published: Aug 29, 2013

Author(s): Carlos Paulo, Maria Dittrich

Journal: Journal of Raman Spectroscopy

Dolomite precipitation, limited at low temperature, appears to be impacted by microbial extracellular polymeric substances (EPS). The presence of dolomites has been reported in the extreme environments of Arabian Gulf sabkhas. Many of these sites are characterized by extensive growth of cyanobacterial mats that are recognized as key producers of EPS. However, no information has been gathered on the cyanobacterial EPS involvement in...

Fluoropolymer‐based clear and white paint coatings composition analysis by X‐Ray fluorescence

Published: Aug 29, 2013

Author(s): P. Ricou, K. Wood

Journal: X-Ray Spectrometry

A new method for the quantification of organic and inorganic phase fractions was developed for fluoropolymer/acrylic‐blend paints – clear and white paint coatings – on aluminum panels by using wavelength dispersive X‐ray fluorescence spectrometry (WDXRF). The method was developed for clear coat samples (only containing fluoropolymer and acrylic phases) as well as white paint samples by also measuring silica and titanium dioxide levels....

Combined quantification of paclitaxel, docetaxel and ritonavir in human feces and urine using LC‐MS/MS

Published: Aug 29, 2013

Author(s): Jeroen J. M. A. Hendrikx, Hilde Rosing, Alfred H. Schinkel, Jan H. M. Schellens, Jos H. Beijnen

Journal: Biomedical Chromatography

ABSTRACT A combined assay for the determination of paclitaxel, docetaxel and ritonavir in human feces and urine is described. The drugs were extracted from 200 μL urine or 50 mg feces followed by high‐performance liquid chromatography analysis coupled with positive ionization electrospray tandem mass spectrometry. The validation program included calibration model, accuracy and precision, carry‐over, dilution test, specificity and...

Simultaneous determination of six C ₂₁ steroids of Xiao‐Ai‐Ping injection in rat plasma by LC‐MS/MS

Published: Aug 28, 2013

Author(s): Qinghua Zeng, Feng Zhang, Shouhong Gao, Liang Sun, Bo Jiang, Wansheng Chen

Journal: Biomedical Chromatography

ABSTRACT Xiao‐Ai‐Ping injection (XAPI) is a traditional Chinese medicine that has been widely used to treat cancer. Modern pharmacological studies have demonstrated that C21 steroids are the main active compounds in XAPI. In this study, a sensitive and specific liquid chromatography tandem mass spectrometry (LC‐MS/MS) method was developed and validated the first time for simultanenous determination of three isomeric pregnane genins...

Bioanalysis of tolvaptan, a novel AVP‐V2 receptor antagonist in human plasma by a novel LC‐ESI‐MS/MS method: a pharmacokinetic application in healthy South Indian male subjects

Published: Aug 28, 2013

Author(s): Venkata Ramu Derangula, Nageswara Rao Pilli, Babu Rao Bhukya, Chalapathi Rao Pulipati, Vinayender Adireddy, Venkateswarlu Ponneri

Journal: Biomedical Chromatography

ABSTRACT A simple, rapid and sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC‐ESI‐MS/MS) assay method is proposed for the determination of tolvaptan in human plasma samples using tolvaptan d7 as internal standard (IS). Analyte and the IS were extracted from 100 μL of human plasma via simple liquid–liquid extraction. The chromatographic separation was achieved on a C18 column using a mixture of methanol and...

Time resolved Raman spectroscopy for depth analysis of multi‐layered mineral samples

Published: Aug 27, 2013

Author(s): Jan‐Hein Hooijschuur, Ingeborg E. Iping Petterson, Gareth R. Davies, Cees Gooijer, Freek Ariese

Journal: Journal of Raman Spectroscopy

Time resolved Raman spectroscopy (TRRS) can provide subsurface information from multi‐layered samples of transparent and translucent evaporative and silicate minerals up to several centimetres thick. Depth information was obtained using 3‐ps pulsed laser excitation at 720 nm and a gated intensified charge‐coupled device detector with stepwise increasing delay times. Blocks of different minerals were used as first, second or third layers,...

Effects of organic modifier and temperature on the enantiomeric separation of several azole drugs using supercritical fluid chromatography and the Chiralpak AD column

Published: Aug 27, 2013

Author(s): L. Toribio, J. L. Bernal, M. T. Martín, J. Bernal, M. J. Nozal

Journal: Biomedical Chromatography

ABSTRACT The effects of organic modifier and temperature on the enantioseparation of 10 triazoles and eight imidazoles, using supercritical fluid chromatography with the Chiralpak AD column, have been investigated in this work. For this purpose four different organic modifiers (methanol, ethanol, 2‐propanol and acetonitrile) were evaluated. Only in the case of two compounds could the enantiomeric separation not be achieved with any...

μ‐Raman spectroscopy of prehistoric paintings from the Abrigo Remacha rock shelter (Villaseca, Segovia, Spain)

Published: Aug 26, 2013

Author(s): Mercedes Iriarte, Antonio Hernanz, Juan F. Ruiz‐López, Santiago Martín

Journal: Journal of Raman Spectroscopy

Abstract The composition of the materials present in prehistoric paintings discovered on the walls of the Abrigo Remacha rock shelter (Villaseca, Segovia, Spain) has been characterised by micro‐Raman spectroscopy. In addition, scanning electron microscopy and energy dispersive X‐ray microanalysis have been used as auxiliary techniques. The results show that haematite (α‐Fe2O3) is the main component of the red pigment. Amorphous carbon and...

Current knowledge on cannabinoids in oral fluid

Published: Aug 25, 2013

Author(s): Dayong Lee, Marilyn A. Huestis

Journal: Drug Testing and Analysis

Oral fluid (OF) is a new biological matrix for clinical and forensic drug testing, offering non‐invasive and directly observable sample collection reducing adulteration potential, ease of multiple sample collections, lower biohazard risk during collection, recent exposure identification, and stronger correlation with blood than urine concentrations. Because cannabinoids are usually the most prevalent analytes in illicit drug testing,...

Two‐dimensional liquid chromatography for direct chiral separations: a review

Published: Aug 24, 2013

Author(s): María Eugenia León‐González, Noelia Rosales‐Conrado, Luis Vicente Pérez‐Arribas, Vanesa Guillén‐Casla

Journal: Biomedical Chromatography

ABSTRACT Separation of enantiomers remains a challenge owing to their identical physical and chemical properties in an achiral environment, and research on specialized separation techniques such as multidimensional achiral–chiral liquid chromatography continues to resolve individual enantiomers in complex samples. Recent advances in application of multidimensional liquid chromatography applied to chiral analysis are reviewed. For...

Simple and validated UHPLC method coupled to UV detection for determination of daptomycin in human plasma and urine

Published: Aug 24, 2013

Author(s): Takafumi Naito, Takahiro Yamada, Tatsuya Yagi, Junichi Kawakami

Journal: Biomedical Chromatography

ABSTRACT Daptomycin, a lipopeptide antibiotic with excellent activity against Gram‐positive bacteria, is excreted primarily by the kidneys. Development of effective chromatographic methodologies for the determination of daptomycin in human specimens is necessary for clinical use. This study developed a simple and validated ultra‐high‐performance liquid chromatography method coupled to ultraviolet detection for determination of...

Development and validation of an LCMS method to determine the pharmacokinetic profiles of caffeic acid phenethyl amide and caffeic acid phenethyl ester in male Sprague–Dawley rats

Published: Aug 24, 2013

Author(s): John Yang, Phillip D. Bowman, Sean M. Kerwin, Salomon Stavchansky

Journal: Biomedical Chromatography

ABSTRACT A validated LCMS method was developed for the quantitative determination of caffeic acid phenethyl amide (CAPA) and caffeic acid phenethyl ester (CAPE) from rat plasma. Separation was achieved using a reverse‐phase C12 HPLC column (150 × 2.00 mm, 4 µm) with gradient elution running water (A) and acetonitrile (B). Mass spectrometry was performed with electrospray ionization in negative mode. This method was used to determine the...