bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantiomeric separation of d‐ and l‐serine using high‐performance liquid chromatography with electrochemical detection following pre‐column diastereomer derivatization
Authors: Yamashita Kazuhide , Fukushima Takeshi , Sasaki Tsukasa , Arai Kotaro , Toyo'oka Toshimasa 
Published: April 2009

AbstractEnantiomeric separation of d‐ and l‐serine on an octadecylsilica column was investigated using (2R)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (R‐NPCA), which was developed for a pre‐column derivatization reagent for electrochemical detection. In addition, (2S)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (S‐NPCA) was newly synthesized from (S)‐(−)‐6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid (S‐α‐CA), and the enantiomeric separation of d‐ and l‐serine using S‐NPCA was also examined. The enantiomeric separation of d,l‐serine was achieved using the R‐ or S‐NPCA as a chiral derivatization reagent, and the elution orders of the enantiomers were reversed between R‐ and S‐NPCA. The elution orders of d‐ and l‐serine unexpectedly reversed between the phosphate buffer at pH 4.0 and pH 2.2, both of which were used in the mobile phase. Separation factors obtained using R‐ and S‐NPCA were similar—1.09 and 1.07, respectively. The detection limit was approximately 940 fmol on the column (signal‐to‐noise ratio 3) when the applied voltage was +650 mV. Copyright © 2009 John Wiley & Sons, Ltd.
Quantification of testosterone undecanoate in human hair by liquid chromatography–tandem mass spectrometry
Authors: Pozo Oscar J. , Deventer Koen , Van Eenoo Peter , Rubens Robert , Delbeke Frans T. 
Published: April 2009

AbstractTestosterone undecanoate (T‐C11) can be used by athletes in order to improve performance. After oral intake, T‐C11 is rapidly metabolized, hampering discrimination between exogenous and endogenous testosterone. A possible alternative is to detect the intact ester in hair. A method based on liquid chromatography–tandem mass spectrometry was developed for the determination of T‐C11 in hair. The sample procedure consisted of digestion of 200 mg of pulverized hair with tris(2‐carboxyethyl)phosphine hydrochloride and liquid–liquid extraction with n‐pentane. Several parameters such as the mobile phase, the ionization source and the washing step were optimized. The method was validated at different spiked levels obtaining satisfactory values for accuracy (between 92 and 102%) with relative standard deviations lower than 7% and a limit of detection of 0.2 ng/g. The applicability of the method was checked by the analysis of three samples from patients using T‐C11. A peak for the analyte was detected in all samples with concentrations between 0.4 and 8.4 ng/g. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of fenofibric acid in human plasma by ultra performance liquid chromatography–electrospray ionization mass spectrometry: application to a bioequivalence study
Authors: Bhavesh Dasandi , Shah Sanjay , Shivprakash  
Published: April 2009

AbstractA rapid, specific and sensitive ultra‐performance liquid chromatography tandem mass spectrometry method was developed for the determination of fenofibric acid in human plasma. The method involves simple, one‐step liquid–liquid extraction procedure coupled with an Acquity UPLCTM BEH C18 column (50 × 2.1 mm, i.d., 1.7 µm) with isocratic elution at a flow‐rate of 0.2 mL/min and mefenamic acid was used as the internal standard. The Quattro Premier XE mass spectrometry was operated under the multiple reaction‐monitoring mode using the electrospray ionization technique. Using 250 µL plasma, the methods were validated over the concentration rang 0.05–7.129 µg/mL, with a lower limit of quantification of 0.05 µg/mL. The intra‐ and inter‐day precision and accuracy were within 9.3%. The recovery was 66.7% and 52.6% for fenofibric acid, and mefenamic acid, respectively. Total run time was 1.8 min only for each sample, which makes it possible to analyze more than 350 samples per day. Copyright © 2009 John Wiley & Sons, Ltd.
Quality evaluation of Hpericum japomicum by using high‐performance liquid chromatography coupled with photodiode array detector and electrospray ionization tandem mass spectrometry
Authors: Gao Wei‐Na , Luo Jian‐Guang , Kong Ling‐Yi 
Published: April 2009

AbstractA high‐performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (HPLC‐PAD‐ESI‐MSn) method was developed to evaluate the quality of Hpericum japomicum through establishing chromatographic fingerprint and simultaneous determination of seven phenolic compounds. The analysis was achieved on an Ultimate XB‐C18 analytical column (250 mm × 4.6 mm i.d., 5 µm) using an aqueous solution of acetic acid (pH 3.8) and methanol as the mobile phase. Ten samples of H. japomicum from various habitats were investigated and the correlation coefficients of similarity were determined from the HPLC fingerprints. By using an online ESI‐MSn, 20 common peaks in chromatographic fingerprints were identified as phenols, including flavones and their glycosides, flavonones and their glucosides, flavanols, xanthones, phloroglucinols, phenyl propanoids and chromones. Based on the above study, seven phenols which are considered to be major constituents in H. japomicum, including 3,4‐dihydroxybenzoic acid (1), taxfolin‐7‐O‐α‐l‐rhamnoside (7), 7‐dihydroxy‐2‐(1‐methylpropyl)chromone‐8‐β‐d‐glucoside (8), isoquercitrin (14), quercitrin (16), quercetin‐7‐O‐α‐l‐rhamnoside (18) and quercetin (19) were quantified by the validated HPLC‐PAD method. This developed method by combination of chromatographic fingerprint and quantification analysis could be applied to control the quality of H. japomicum. Copyright © 2009 John Wiley & Sons, Ltd.
Performance tradeoffs among low‐complexity detection algorithms for MIMO‐LTE receivers
Authors: Morales‐Jiménez D. , Paris J. F. , Entrambasaguas J. T. 
Published: April 2009

AbstractThe upcoming Third‐Generation Partnership Project—Long‐Term Evolution (3GPP‐LTE) cellular standard will employ spatial multiplexing to significantly increase the data rates. Detection of the spatially multiplexed signals is an essential issue in the design of an LTE receiver. In this paper, we evaluate the performance–complexity tradeoffs for a set of low‐complexity multiple input multiple output (MIMO) detection algorithms in a realistic LTE downlink system. Specifically, antenna correlation and channel estimation errors have been considered for a practical MIMO‐LTE receiver. An LTE downlink model has been implemented in order to evaluate three types of detectors: linear, unsorted successive interference cancellation (SIC), and ordered SIC. Our simulation results show that the unsorted SIC detectors present a very poor performance–complexity tradeoff. Besides, linear detectors are shown to be the best candidates as the performance improvement for the ordered SIC detectors is not significant in a realistic scenario. Copyright © 2009 John Wiley & Sons, Ltd.
Sequential changes in coagulation after renal transplantation: A thromboelastogram study
Authors: Timmermans Joep , Dolmans Guido H. C. , Kahn Delawir 
Published: April 2009

AbstractBACKGROUNDChronic renal failure is associated with complex alterations in coagulation. The changes in coagulation that occur after renal transplantation have been studied only to a limited extent. The thromboelastogram (TEG) provides a global assessment of whole blood clotting. In this study, sequential changes in coagulation after renal transplantation were investigated in 8 patients using the TEG.METHODSThe controls included normal healthy controls (n = 6) and patients on hemodialysis (n = 5), on peritoneal dialysis (n = 6), and long term after transplantation (n = 7). The TEG parameters measured included R‐time, K‐time, alpha angle, and maximum amplitude.RESULTSThe TEG parameters pre‐transplantation demonstrated a hypercoagulable state. There was a trend toward normal coagulation immediately after transplantation (days 2–4) and a return to hypercoagulability thereafter, compared with the normal controls. There was no difference in the TEG parameters between the patients long term after transplantation and the normal controls. The dialysis patients were also hypercoagulable.CONCLUSIONSPatients with end‐stage renal failure on dialysis are hypercoagulable, and this persists in the early post‐transplant period. However patients long term after transplantation have normal coagulation.
Early and prolonged continuous hemodiafiltration for the treatment of severe metformin‐associated lactic acidosis
Authors: Abramo Antonio , Corini Marzia , Malacarne Paolo , Donadio Francesca , Donadio Carlo 
Published: April 2009

AbstractIn this article, we discuss the case of a 42‐year‐old female diabetic patient who developed severe lactic acidosis, coma, shock, rhabdomyolysis, and renal and hepatic failure during metformin therapy after alcohol abuse. The APACHE II score of this patient was 38, which is associated with an estimated mortality rate >88%. Conventional treatment of acidosis with IV infusion of sodium bicarbonate (400 mmol) was ineffective in restoring a normal acid/base balance. Lactic acidosis was successfully treated with bicarbonate‐buffered continuous veno‐venous hemodiafiltration. The patient also had a complete recovery from all complications.
Anti‐angiogenic potential of scopoletin is associated with the inhibition of ERK1/2 activation
Authors: Pan Rong , Dai Yue , Yang Jian , Li Ying , Yao Xiujuan , Xia Yufeng 
Published: April 2009

AbstractAngiogenesis plays an important role in many diseases, such as cancer, rheumatoid arthritis, and diabetic retinopathy. Specific inhibitors of angiogenesis are therefore expected to be potential candidate therapeutics for these disorders. Recently, several naturally occurring coumarins and synthetic analogues have proved to hinder new vessel formation. The present study was undertaken to investigate the effects of scopoletin, a phenolic coumarin compound with various biological activities on endothelial cell activation and resultant angiogenesis. Scopoletin had no cytotoxic effect on endothelial cells at the concentrations tested but suppressed the endothelial cell migration and disrupted rat tail collagen tube formation at concentrations of 62.5, 125, 250, and 500 µM, whereas it only moderately inhibited the proliferation and adhesion of endothelial cells. Notably, scopoletin (500 µM) selectively downregulated serum‐induced ERK1/2 phosphorylation, without affecting endothelial cell p38 MAPK or JNK phosphorylation. These findings demonstrate that scopoletin has anti‐angiogenic properties that are manifest mainly through inhibiting migration and tube formation of endothelial cells via downregulating ERK1/2 activation. Scopoletin may potentially be useful for the treatment of angiogenesis‐mediated diseases and could serve as a structural basis for screening for more potent synthetic analogues. Drug Dev Res 2009. © 2009 Wiley‐Liss, Inc.
Synaptotagmin I stabilizes synaptic vesicles via its C2A polylysine motif
Authors: Mace Kimberly E. , Biela Laurie M. , Sares Anastasia G. , Reist Noreen E. 
Published: April 2009

AbstractThe synaptic vesicle protein, synaptotagmin I, is a multifunctional protein required for several steps in the synaptic vesicle cycle. It is primarily composed of two calcium‐binding domains, C2A and C2B. Within each of these domains, a polylysine motif has been identified that is proposed to mediate specific functions within the synaptic vesicle cycle. While the C2B polylysine motif plays an important role in synaptic transmission in vivo, the C2A polylysine motif has not previously been analyzed at an intact synapse. Here, we show that mutation of the C2A polylysine motif increases the frequency of spontaneous transmitter release in vivo. The increased frequency is not a developmental consequence of disrupted synaptic transmission, as evoked transmitter release is unimpaired in the mutants. Our results demonstrate that synaptotagmin I plays a direct role in regulating spontaneous transmitter release, indicative of an active role in synaptic vesicle stabilization mediated by the C2A polylysine motif. genesis 47:337–345, 2009. © 2009 Wiley‐Liss, Inc.
Cytotoxic Titanium(IV) Complexes: Renaissance
Authors: Tshuva Edit Y. , Ashenhurst James A. 
Published: April 2009

AbstractIn this paper we overview our studies on amine–phenolato TiIV complexes as cytotoxic agents, in the context of the results reported thus far with titanocene dichloride, budotitane and derivatives. In particular, we emphasize the studies about the structure–activity relationship performed and important insights gained with the known compounds and our complexes, in regards to their hydrolytic behavior and cytotoxic activity, while pointing to potential mechanistic aspects. Titanocene dichloride and budotitane show cytotoxic activity towards cells that are resistant to cisplatin with reduced side effects. Their main drawback is their hydrolytic instability that has impeded mechanistic investigations and pharmaceutical use. Our new family of cytotoxic complexes was designed to include a single highly electron‐donating chelating ligand to afford octahedral TiIV complexes of relatively high hydrolytic stability, with the aim to retain ligand binding throughout the biological activity for achieving controlled processes and allowing mechanistic evaluation. The effect of several parameters on hydrolysis and cytotoxicity were investigated, including those relating to the tetradentate ligand and those relating to the labile groups. Overall we observed high cytotoxic activity that is strongly dependent on the ligand, and which is strongly correlated to the complex hydrolytic behavior. Additional mechanistic studies provide insights regarding the time frame of activity and cell penetration. Some comparisons to titanocene dichloride, budotitane and analogues are highlighted.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Highly Regioselective Oxirane Ring‐Opening of a Versatile Epoxypyrrolidine Precursor of New Imino‐Sugar‐Based Sphingolipid Mimics
Authors: Rives Arnaud , Génisson Yves , Faugeroux Vanessa , Zedde Chantal , Lepetit Christine , Chauvin Remi , Saffon Nathalie , Andrieu‐Abadie Nathalie , Colié Sandra , Levade Thierry , Baltas Michel 
Published: April 2009

AbstractAn in‐depth study of the oxirane ring‐opening reaction of a pivotal epoxypyrrolidine is reported. The introduction of various carbon‐ and heteroatom‐centered nucleophiles at C4 has been achieved with high regiocontrol. The structures of the major products were assigned on the basis on an X‐ray crystallographic study of six examples. A mechanistic study carried out at the B3LYP/6‐31G** level of theory suggested that the steric control of the vinyl substituent was responsible for the regioselectivity. Finally, this approach was used to design and prepare imino‐sugar‐based sphingolipid mimics. A highly cytotoxic C‐octylpyrrolidine is described. This compound was shown to interfere with the metabolism of sphingolipids in murine melanoma cells, notably in inhibiting the production of glucosylceramide. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Combinations of Acidic and Basic Monodentate Binaphtholic Phosphites as Supramolecular Bidentate Ligands for Enantioselective Rh‐Catalyzed Hydrogenations
Authors: Pignataro Luca , Lynikaite Benita , Cvengroš Ján , Marchini Mattia , Piarulli Umberto , Gennari Cesare 
Published: April 2009

AbstractA small library of chiral BINOL‐derived monodentate phosphites containing either a carboxylic acid (‐COOH, A1–A3) or a tertiary amine (‐NMe2, B1–B4) was synthesized. The ligand combinations were screened in the enantioselective rhodium‐catalyzed hydrogenation of methyl 2‐acetamidoacrylate. The heterocombinations of the amine‐derived phosphite (R)‐B2 and of a carboxylic‐phosphite [(R)‐A1, (R)‐A2, (R)‐A3] displayed a slightly higher level of enantioselectivity compared to the corresponding homocombinations [up to 90 % ee using (R)‐A1/(R)‐B2]. The nature and extent of the interaction between the acidic and basic ligands in the rhodium complexes were studied by IR and 31P‐NMR spectroscopy. The formation of an intramolecular salt in the Rh‐heterocomplex, between the carboxylic acid and the tertiary amine, was suggested by the IR spectra. The selective formation of the Rh‐heterocomplex was quantitatively assessed by 31P‐NMR spectroscopy, using a modified acidic ligand (R)‐A1‐Me. In this way, a moderate (ca. 70:30) heterocomplex/homocomplexes ratio was determined.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
The therapeutic effect of rituximab on CD5‐positive and CD5‐negative diffuse large B‐cell lymphoma
Authors: Hyo Rie , Tomita Naoto , Takeuchi Kengo , Aoshima Tomohiro , Fujita Atsuko , Kuwabara Hideyuki , Hashimoto Chizuko , Takemura Sachiya , Taguchi Jun , Sakai Rika , Fujita Hiroyuki , Fujisawa Shin , Ogawa Koji , Motomura Shigeki , Suzuki Ritsuro , Ishigatsubo Yoshiaki 
Published: April 2009

AbstractThe prognosis of diffuse large B‐cell lymphoma (DLBCL) has improved markedly in recent years of rituximab era. The prognosis of de novo CD5‐positive DLBCL is reported to be poor, but the effect of rituximab on this type of lymphoma remains unclear. To investigate the effect of rituximab on CD5‐positive DLBCL, we collected DLBCL patients and analysed prognostic factors. A total of 157 patients with DLBCL who were immunophenotyped with flow‐cytometry (FCM) and treated with chemotherapy were subjected to analysis. Those treated with radiotherapy alone or with supportive therapy only were not included. Patients diagnosed in 2003 or later were treated with rituximab combined chemotherapy. There were 95 males and 62 females. Their age ranged from 20 to 91 years old, and the median was 65 years. Nineteen patients were diagnosed as having de novo CD5‐positive DLBCL. Rituximab was given alongside chemotherapy in 85 patients. Of these, 11 were positive for CD5 and 74 were negative. The addition of rituximab improved the overall survival (OS) of DLBCL patients (2‐year OS: 82% vs. 70%, p = 0.01). For CD5‐negative DLBCL, patients treated with rituximab showed 2‐year OS of 84%, which was significantly better than those treated without rituximab (70%, p = 0.008). However, for CD5‐positive DLBCL, the prognosis was not statistically different between the patients treated with and without rituximab (59% vs. 50%, p = 0.72). Although rituximab improved the prognosis of DLBCL, such improvement was restricted to the CD5‐negative group. Further investigation is required to improve the prognosis of patients with CD5‐positive DLBCL. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and antibacterial activity of nisin‐containing block copolymers
Authors: Joshi Pranav R. , McGuire Joseph , Neff Jennifer A. 
Published: April 2009

AbstractNisin, an antibacterial peptide proven to be an effective inhibitor of Gram‐positive bacteria, was incorporated into novel block copolymer constructs and tested for retained antibacterial activity. Covalent coupling was achieved by chemical modification of the N‐terminal isoleucine to introduce a thiol group. Thiolated‐nisin derivatives were then linked to poly[ethylene oxide]‐poly[propylene oxide]‐poly[ethylene oxide] (PEO‐PPO‐PEO) triblocks that had been end‐activated such that terminal hydroxyl groups of the PEO chains were replaced with pyridyl disulfide moieties. The nisin‐containing block copolymers were separated from free nisin by dialysis and showed antimicrobial activity against the Gram‐positive indicator strain Pediococcus pentosaceus. The contribution to antimicrobial activity from nisin that was covalently linked was not distinguished from the contribution of nisin that had associated with the PEO‐PPO‐PEO triblocks through noncovalent interactions. However, nisin that was covalently linked showed activity upon reduction of the disulfide bond and release from the end‐activated PEO. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Mindfulness in Thailand and the United States: a case of apples versus oranges?
Authors: Christopher Michael S. , Charoensuk Sukjai , Gilbert Brennan D. , Neary Timothy J. , Pearce Kelly L. 
Published: April 2009

AbstractThe study and practice of mindfulness is rapidly expanding in Western psychology. Recently developed self‐report measures of mindfulness were derived from Western operationalizations and cross‐cultural validation of many of these measures is lacking, particularly in Buddhist cultures. Therefore, this study examined the measurement equivalence of the Kentucky Inventory of Mindfulness Skills (KIMS) and Mindful Attention Awareness Scale (MAAS) among Thai (n=385) and American (n=365) college students. Multigroup confirmatory factor analysis models fit to the data revealed that the KIMS lacked configural invariance across groups, which precluded subsequent invariance tests, and although the MAAS demonstrated configural, metric, and partial scalar invariance, there was no significant latent mean MAAS difference between Thais and Americans. These findings suggest that Eastern and Western conceptualizations of mindfulness may have important differences. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1–23, 2009.
Endothelin‐1 gene polymorphism and hearing impairment in elderly Japanese
Authors: Uchida Yasue , Sugiura Saiko , Nakashima Tsutomu , Ando Fujiko , Shimokata Hiroshi 
Published: April 2009

AbstractObjectives/Hypothesis:To investigate the association between the Lys198Asn (G/T) polymorphism (rs5370) in the endothelin‐1 gene (EDN1) and hearing impairment in middle‐aged and elderly Japanese.Study Design:Longitudinal study.Methods:Data were collected from community‐dwelling Japanese adults who participated in the Longitudinal Study of Aging biennially between 1997 and 2006. The participants at baseline were 2,231 adults aged 40 years to 79 years. An average hearing threshold level of 25 dB or better in the better ear for frequencies 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz was defined as no hearing impairment. Using generalized estimating equations to treat repeated observations within subjects, 7,097 cumulative data were analyzed to assess the association between hearing status and the EDN1 G/T polymorphism with adjustment for age, sex, histories of ear disease, occupational noise exposure, heart disease, hypertension, and body mass index under additive, dominant, and recessive genetic models.Results:Comparison with wild‐type homozygotes (GG), heterozygotes, and mutant homozygotes (GT/TT) showed a positive association with hearing impairment after adjustment for age in model 1 (odds ratio [OR] = 1.24; 95% confidence interval [CI] = 1.02–1.50; P = .033), for age and sex in model 2 (OR = 1.29; CI = 1.06–1.57; P = .0122), and for age, sex, history of ear disease, and history of occupational noise exposure in model 3 (OR = 1.31; CI = 1.07–1.60; P = .0092). The association was also significant in model 3 under the additive model.Conclusions:This study demonstrated that mutant T‐allele carriers were associated with a higher risk of hearing impairment than carriers of wild‐type homozygotes in middle‐aged and elderly people. This result implies that endothelin‐1 plays a valuable role in the cochlea. Laryngoscope, 2009