bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of quinidine, cimetidine, and ketoconazole on the enantioselective pharmacokinetics and metabolism of metoprolol in rats
Authors: Boralli Vanessa Bergamin , Coelho Eduardo Barbosa , Lanchote Vera Lucia 
Published: January 2009

AbstractMetoprolol is a β‐blocker and its racemic mixture is used for the treatment of hypertension. In the present study we investigated the influence of CYP2D and CYP3A on the stereoselective metabolism of metoprolol in rats. Male Wistar rats (n= 6 per group) received racemic metoprolol (15 mg/kg) orally, with or without pretreatment with the CYP inhibitor ketoconazole (50 mg/kg), cimetidine (150 mg/kg), or quinidine (80 mg/kg). Blood samples were collected up to 48 h after metoprolol administration. The plasma concentrations of the stereoisomers of metoprolol,O‐demethylmetoprolol (ODM), α‐hydroxymetoprolol (OHM) (Chiralpak® AD column), and metoprolol acidic metabolite (AODM) (Chiralcel® OD‐R column) were determined by HPLC using fluorescence detection (λexc= 229 nm; λem= 298 nm). CYP3A inhibition by ketoconazole reduced the plasma concentrations of ODM and AODM and favored the formation of OHM. CYP2D and CYP3A inhibition by cimetidine reduced the plasma concentrations of OHM and AODM and favored the formation of ODM. The inhibition of CYP2D by quinidine reduced the plasma concentrations of OHM and favored the formation of ODM. In conclusion, the results suggest that CYP3A is involved in the formation of ODM and CYP2D is involved in the formation of AODM. Chirality 2009. © 2009 Wiley‐Liss, Inc.
Desymmetrization of cyclic anhydrides mediated by cinchona alkaloids: Synthesis and olfactory properties of new fragrances based on (R)‐ and (S)‐2‐ethylhexanol
Authors: Ćiško‐Anić Blaženka , Hameršak Zdenko 
Published: January 2009

AbstractA series of enantiomerically pure new fragrances, derived from 2‐ethylhexanol, have been prepared and their olfactory properties evaluated. The key step of the synthesis is cinchona‐alkaloid‐catalyzed desymmetrization of cyclic meso‐anhydrides with (R)‐ and (S)‐2‐ethylhexanol and proceeded in good to excellent diastereoselectivities (92:8–98:2 dr). Enantiomerically pure alcohols were prepared by lipase‐catalyzed kinetic resolution of 2‐ethylhexanol using vinyl laurate as acyl donor. Chirality 2009. © 2009 Wiley‐Liss, Inc.
Determination of the absolute configuration of aromatase and dual aromatase‐sulfatase inhibitors by vibrational and electronic circular dichroism spectra analysis
Authors: Abbate Sergio , Longhi Giovanna , Castiglioni Ettore , Lebon France , Wood Paul M. , Woo Lawrence W. L. , Potter Barry V. L. 
Published: January 2009

AbstractThe absolute configuration of a newly designed, letrozole‐based chiral aromatase inhibitor that could not be defined by crystallographic techniques has been determined by means of vibrational and electronic circular dichroism and by optical rotation measurements combined with density functional theory calculations on possible conformers. The same absolute configurational assignment can be applied to the individual enantiomeric sulfamate esters, which are derived from the corresponding enantiomers of the chirally separated parent phenols, based on the similarity of the ECD spectrum of the sulfamate derivative to that of its phenolic precursor. The two enantiomeric sulfamate esters studied here are the first examples of nonsteroidal dual aromatase‐sulfatase inhibitor whose activities have been evaluated on optically resolved enantiomers. Chirality 2009. © 2009 Wiley‐Liss, Inc.
Growing Duckweed to Recover Nutrients from Wastewaters and for Production of Fuel Ethanol and Animal Feed
Authors: Cheng Jay J. , Stomp Anne‐M. 
Published: January 2009

AbstractLemnaceae or duckweed is an aquatic plant that can be used to recover nutrients from wastewaters. The grown duckweed can be a good resource of proteins and starch, and utilized for the production of value‐added products such as animal feed and fuel ethanol. In the last eleven years we have been working on growing duckweed on anaerobically treated swine wastewater and utilizing the duckweed for fuel ethanol production. Duckweed strains that grew well on the swine wastewater were screened in laboratory and greenhouse experiments. The selected duckweed strains were then tested for nutrient recovery under laboratory and field conditions. The rates of nitrogen and phosphorus uptake by the duckweed growing in the laboratory and field systems were determined in the study. The mechanisms of nutrient uptake by the duckweed and the growth of duckweed in a nutrient‐limited environment have been studied. When there are nutrients (N and P) available in the wastewater, duckweed takes the nutrients from the wastewater to support its growth and to store the nutrients in its tissue. When the N and P are completely removed from the wastewater, duckweed can use its internally stored nutrients to keep its growth for a significant period of time. A modified Monod model has been developed to describe nitrogen transport in a duckweed‐covered pond for nutrient recovery from anaerobically treated swine wastewater. Nutrient reserve in the duckweed biomass has been found the key to the kinetics of duckweed growth. Utilization of duckweed for value‐added products has a good potential. Using duckweed to feed animals, poultry, and fish has been extensively studied with promising results. Duckweed is also an alternative starch source for fuel ethanol production. Spirodela polyrrhiza grown on anaerobically treated swine wastewater was found to have a starch content of 45.8% (dry weight). Enzymatic hydrolysis of the duckweed biomass with amylases yielded a hydrolysate with a reducing sugar content corresponding to 50.9% of the original dry duckweed biomass. Fermentation of the hydrolysate using yeast gave an ethanol yield of 25.8% of the original dry duckweed biomass. These results indicate that the duckweed biomass can produce significant quantities of starch that can be readily converted into ethanol.
Ti0.99Pd0.01O2−δ: A New Pt‐free Catalyst for High Rates of H2+O2 Recombination with High CO Tolerant Capacity
Authors: Sharma Sudhanshu , Hegde Manjanath S. 
Published: January 2009

AbstractA platinum‐free H2/O2 recombination catalyst, Ti0.99Pd0.01O2−δ, is synthesized by a solution combustion method where Pd2+ ions adsorb protonic H2δ+ ion and oxygen on the oxide ion vacancy sites (see picture). The rate of H2+O2 recombination at 50 °C is 15 μmoles g−1 s−1, which is much higher than that of Pt‐containing catalysts.magnified image
Field‐Effect Transistors with Mixed Ionic‐Electronic Gate
Authors: Saheb Amir , Josowicz Mira , Janata Jiří 
Published: January 2009

AbstractField‐effect transistors with mixed ionic‐electronic conductors have been prepared by varying the ratio of room temperature ionic liquid and emeraldine salt of polyaniline. Transistor with sufficiently high electronic conductivity (32 mol% ES‐PANI) and Au gate contact exhibited theoretical behavior of insulated gate field‐effect transistor. On the other hand the purely ionic gate behaved irreproducibly, indicating that a capacitive divider has been formed in the gate.
Detection of Abasic Sites in DNA by Electrochemical, Immunoelectrochemical and Acoustic Methods Using OsO4, 2,2′‐bipyridine as a Probe for Unpaired Thymine Residues
Authors: Bartošík Martin , Gajdoš Viktor , Kostečka Pavel , Fojta Miroslav , Paleček Emil , Volkov Eugeny , Oretskaya Tatiana , Hianik Tibor 
Published: January 2009

AbstractWe report on comparative analysis of the detection of DNA damage modeled by presence of abasic sites (AP) at defined positions using the chemical modification of the DNA by the complex of osmium tetroxide‐2,2‐bipyridine (Os, bipy) that selectively binds to unpaired thymine residues in the damaged DNA. AP were detected by electrochemical detection (EC) of the Os, bipy‐thymine adducts, by immunoelectrochemical (IE) and by thickness shear mode acoustic methods (TSM). EC method of detection can perfectly distinguish between the number of AP. IE and TSM methods were of comparable sensitivity.
Electrochemical Behavior of Nanoelectrode Ensembles in the Ionic Liquid [BMIm][BF4]
Authors: De Leo Manuela , Moretto Ligia Maria , Buriez Olivier , Ugo Paolo 
Published: January 2009

AbstractThe electrochemical behavior of nanoelectrode ensembles (NEEs), prepared by electroless plating of Au using microporous polycarbonate membranes as template, is tested in the ionic liquid [BMIm][BF4]. The accessible potential window is significantly wider in [BMIm][BF4] than in water, extending approximately, for 3.4 V vs. 1 V, respectively. The voltammetric behavior at NEEs of two redox probes, namely butyl viologen (BV2+) and (ferrocenylmethyl) trimethylammonium (FA+) are examined at different scan rates. In both cases, at scan rates higher than 200 mV/s sigmoidally shaped voltammograms typical of a pure radial diffusion regime are observed. At lower scan rates the voltammograms are peak shaped, as expected for total overlap diffusion conditions. This is the first time that the pure radial regime is obtained with NEEs made using commercially available polycarbonate templates, since in water solution only the total overlap regime is typically observed. This is explained as a consequence of the high viscosity of [BMIm][BF4] which reflects in lowering of diffusion coefficients and smaller thickness of diffusion layers, for the same time scale, with respect to water solutions, but also the fact that the nanoelectrodes are slightly recessed helps in observing the pure radial regime. In order to make operative the pure radial condition it is indeed required that the thickness of diffusion layer at individual nanoelectrodes be smaller than the hemi‐distance between neighboring nanoelectrodes. Examining the analytical performances achievable with NEEs in [BMIm][BF4], it is shown that a limit is given by the decreased diffusion coefficients. Detection limits at NEEs in the ionic liquid are indeed higher than those obtained in water solutions. This notwithstanding, detections limits at NEEs in [BMIm][BF4] are always improved with respect to those at conventional electrodes.
Bismuth Film Electrode in Metal Complexation Studies: Stripping Analysis of the Pb(II)‐, Cd(II)‐, and Zn(II)‐Binding with Phthalate
Authors: Serrano Núria , Martín Nuria , Díaz‐Cruz José Manuel , Ariño Cristina , Esteban Miquel 
Published: January 2009

AbstractThe possibilities of bismuth film electrode for complexation studies by anodic stripping voltammetry (ASV) and constant current stripping chronopotentiometry (CCSCP) are tested for Pb(II), Cd(II), and Zn(II) in the presence of phthalate. In all cases, labile complexes are detected. The regular signals obtained for the Pb(II)‐phthalate system allow an accurate determination of stability constants by means of the DeFord‐Hume method. As for Cd(II)‐ions, the two overlapping signals usually present in the absence of ligands suffer a similar evolution with the addition of phthalate. Then, the use of an intermediate potential between both signals allows a reasonable estimation of stability constants. In contrast, the two overlapping signals obtained for Zn(II) behave in a quite irregular way in the presence of phthalate, thus hindering any quantitative analysis of the formed complexes.
Voltammetric Study of Adenine Complex with Copper on Mercury Electrode
Authors: Jelen Frantisek , Kourilova Alena , Hason Stanislav , Kizek Rene , Trnkova Libuse 
Published: January 2009

AbstractThe determination of adenine (Ade), adenosine (Ado) and hydrolyzed adenosine (h‐Ado) in the presence of copper(II) ions is described by cyclic (CV) and elimination voltammetry with linear scan (EVLS) in connection with adsorptive stripping technique. Signals of adenine and copper‐adenine complex were measured on a hanging mercury drop electrode (HMDE) in buffered solutions with different pH. The differences in electrochemical behavior of Ade and Ado were found not only in dependence on the presence of copper ions, scan rate, Ade concentration and pH, but also on the accumulation time and potential where a copper‐Ade complex is formed. A deeper evaluation of voltammetric responses was carried out by EVLS. The EVLS function E4 eliminating charging and kinetic current components and conserving the diffusion current component was capable of enhancing the current sensitivity of CV peaks and of detecting electron transfer in adsorbed state. The irreversible electrode process of a totally adsorbed electroactive species is indicated by means of a peak‐counterpeak signal. Our results show that EVLS in connection with the adsorptive stripping procedure is not only a useful tool for both qualitative and quantitative microanalysis of Ade but also for revealing certain details in electrode processes.
Chronopotentiometric Stripping Analysis of Gelatinase B, Collagen and Their Interaction
Authors: Huska Dalibor , Adam Vojtech , Zitka Ondrej , Kukacka Jiri , Prusa Richard , Kizek Rene 
Published: January 2009

AbstractMatrix metalloproteinases (MMP) belong to a group of zinc‐dependent proteins that play a central role in the breakdown of extracellular matrices. Collagen, elastin, gelatin and casein are the main components of extracellular matrix cleaved by MMP. This paper aims to analyze the interaction between gelatinase B (MMP‐9) and collagen using chronopotentiometric stripping analysis with adsorptive transfer stripping technique (AdTS CPSA). Under optimized experimental conditions (time accumulation of 90 s, supporting electrolyte 0.2 M acetate buffer pH 5, stripping current 1 μA), the detection limit (3 signal/noise) for MMP‐9 was estimated as being 100 pM. The interaction between MMP‐9 and collagen was studied according to the following scheme: i) HMDE surface was renewed. ii) Renewed surface of HMDE collagen (1 μg/mL) was accumulated for 90 s under open circuit. iii) The electrode was rinsed in ACS grade water and immersed in 5 μL drop of MMP‐9. iv) The interaction between MMP‐9 with collagen took place at open circuit. v) The electrode was then rinsed in ACS grade water. vi) The rinsed electrode was transferred into an electrochemical cell and measured in acetate buffer (pH 5). The CPSA signal of collagen after its interaction with MMP‐9 increased more than 30% compared to that of only collagen. This increase in signal is likely due to the cleavage of collagen by MMP‐9, hence its easy access to the electrode's surface.
An Experimental Investigation of Quasireversible Maximum of Azobenzene on Mercury Electrode by Fourier Transformed Square‐Wave Voltammetry
Authors: Wang Lishi , Chen Huilian , Huang Xinjian , Nan Junmin 
Published: January 2009

AbstractAn experimental investigation of quasireversible maximum (QRM) of azobenzene on mercury electrode by two methods, i.e., traditional square‐wave voltammetry (SWV) and fast Fourier transformed square‐wave voltammetry (FT‐SWV), was presented, and the influence factors on QRM of FT‐SWV were discussed. The results show that the rate constants derived from FT‐SWV agree with that of derived from traditional SWV with acceptable differences, showing a sound verification that the rate constants derived from FT‐SWV were reliable. In addition, some theoretical predictions on FT‐SWV were experimentally confirmed through the characterization of strongly adsorbed azobenzene on mercury film electrode. As a result, FT‐SWV is further proved to be a powerful technique in kinetic studies of the surface adsorbed processes.
High Performance Oxide Functionalized Nitrogen‐Doped Mesocellular Carbon Foam for Biosensor Construction
Authors: Shi Linpu , Gao Qiuming , Wu Yihua 
Published: January 2009

AbstractNitrogen‐doped mesocellular carbon foam (denoted as MCFCNx) with high surface area and large pore volume was prepared and characterized in detail. The MCFCNx was further functionalized by oxidation with HNO3 (denoted as MCFCNx‐O) in order to effectively improve its hydrophilicity and biocompatibility. Both MCFCNx and MCFCNx‐O were used for immobilization of Hb and design of electrochemical biosensors. The activity of Hb immobilized on MCFCNx‐O is two times higher than that of Hb immobilized on MCFCNx. The Hb‐MCFCNx‐O‐Nafion modified electrode displays fast response, high sensitivity and low detection limit to the detection of hydrogen peroxide. The sensitivity of Hb‐MCFCNx‐O‐Nafion modified electrode (477 μA mM−1 cm−2) is twice that of Hb‐MCFCNx‐Nafion modified electrode.
Restoration of XAF1 expression induces apoptosis and inhibits tumor growth in gastric cancer
Authors: Tu Shui Ping , Liston Peter , Cui Jian Tao , Lin Marie C.M. , Jiang Xiao Hua , Yang Yi , Gu Qing , Jiang Shi Hu , Lum Ching Tung , Kung Hsiang Fu , Korneluk Robert G , Wong Benjamin Chun‐Yu 
Published: January 2009

AbstractXAF1 (XIAP‐associated factor 1) is a novel XIAP binding protein that can antagonize XIAP and sensitize cells to other cell death triggers. Our previous results have shown that aberrant hypermethylation of the CpG sites in XAF1 promoter is strongly associated with lower expression of XAF1 in gastric cancers. In our study, we investigated the effect of restoration of XAF1 expression on growth of gastric cancers. We found that the restoration of XAF1 expression suppressed anchorage‐dependent and ‐independent growth and increased sensitivity to TRAIL and drug‐induced apoptosis. Stable cell clones expressing XAF1 exhibited delayed tumor initiation in nude mice. Restoration of XAF1 expression mediated by adenovirus vector greatly increased apoptosis in gastric cancer cell lines in a time‐ and dose‐dependent manner and sensitized cancer cells to TRAIL and drugs‐induced apoptosis. Adeno‐XAF1 transduction induced cell cycle G2/M arrest and upregulated the expression of p21 and downregulated the expression of cyclin B1 and cdc2. Notably, adeno‐XAF1 treatment significantly inhibited tumor growth, strongly enhanced the antitumor activity of TRAIL in a gastric cancer xenograft model in vivo, and significantly prolonged the survival time of animals bearing tumor xenografts. Complete eradication of established tumors was achieved on combined treatment with adeno‐XAF1 and TRAIL. Our results document that the restoration of XAF1 inhibits gastric tumorigenesis and tumor growth and that XAF1 is a promising candidate for cancer gene therapy. © 2009 UICC
Evaluation of nonviral risk factors for nasopharyngeal carcinoma in a high‐risk population of Southern China
Authors: Guo Xiuchan , Johnson Randall C. , Deng Hong , Liao Jian , Guan Li , Nelson George W. , Tang Mingzhong , Zheng Yuming , de The Guy , O'Brien Stephen J. , Winkler Cheryl A. , Zeng Yi 
Published: January 2009

AbstractTo understand the role of environmental and genetic influences on nasopharyngeal carcinoma (NPC) in populations at high risk of NPC, we have performed a case‐control study in Guangxi Province of Southern China in 2004–2005. NPC cases (n = 1,049) were compared with 785 NPC‐free matched controls who were seropositive for IgA antibodies (IgA) to Epstein‐Barr virus (EBV) capsid antigen (VCA)—a predictive marker for NPC in Chinese populations. A questionnaire was used to capture exposure and NPC family history data. Risk factors associated with NPC in a multivariant analysis model were the following: (i) a first, second or third degree relative with NPC [attributable risk (AR)= 6%, odds ratio (OR) = 3.1, 95% confidence interval (CI) = 2.0–4.9, p < 0.001]; (ii) consumption of salted fish 3 or more than 3 times per month (AR = 3%, OR = 1.9, 95% CI = 1.1–3.5, p = 0.035); (iii) exposure to domestic wood cooking fires for more than 10 years (AR = 69%, OR = 5.8, 95% CI = 2.5–13.6, p < 0.001); and (iv) exposure to occupational solvents for 10 or less years (AR = 4%, OR = 2.6, 95% CI = 1.4–4.8, p = 0.002). Consumption of preserved meats or a history of tobacco smoking were not associated with NPC (p > 0.05). We also assessed the contribution of EBV/IgA/VCA antibody serostatus to NPC risk—32.2% of NPC can be explained by IgA+ status. However, family history and environmental risk factors cumulatively explained only 2.7% of NPC development in NPC high risk population. These findings should have important public health implications for NPC risk reduction in endemic regions. © 2009 UICC
Tetraspanin gene expression levels as potential biomarkers for malignancy of gingival squamous cell carcinoma
Authors: Hirano Chizuru , Nagata Masaki , Noman Arhab A. , Kitamura Nobutaka , Ohnishi Makoto , Ohyama Tokio , Kobayashi Takanori , Suzuki Kenji , Yoshizawa Michiko , Izumi Naoya , Fujita Hajime , Takagi Ritsuo 
Published: January 2009

AbstractAccurate assessment of malignancy in oral squamous cell carcinoma is essential to optimize treatment planning. To detect a biomarker related to malignant propensity in gingival squamous cell carcinoma (GSCC), quantitative gene expression analysis of tetraspanin family genes was conducted. In 73 cases of GSCC, total RNA was extracted from carcinoma tissues, and gene expression was analyzed by quantitative real time‐PCR. Six tetraspanin family genes (CD9, CD63, CD81, CD82, CD151, NAG‐2) were investigated. Housekeeping genes (ACTB and GAPDH), anchor protein genes (JUP and PXN) and an integrin gene (ITGA3) were used as reference genes. Forty‐five gene expression ratios were calculated from these 11 gene expression levels and were analyzed with clinical parameters using multivariate statistical methods. According to the results of the logistic regression analysis subjecting cervical lymph node metastasis as a target variable, CD9/ACTB (p = 0.013) or CD9/CD82 (p = 0.013) in addition to tumor size (p = 0.028) were detected as significant factors. In Cox proportional hazards regression analysis, delayed cervical lymph node metastasis (p = 0.039) and tumor cell positive surgical margin (p = 0.032) in addition to CD151/GAPDH (p = 0.024) were detected as significant factors for death outcome. A Kaplan‐Meier survival curve presented a significantly lower survival rate of the group with a CD151/GAPDH value of 10 or more (log rank and generalized Wilcoxon tests: p = 0.0003). Results of this study present the usefulness of CD9 and CD151 expression levels as biomarkers for assessment of malignancy in GSCC. They also indicate that detection of residual tumor cells at the surgical margin and the biological malignancy of a tumor interdependently affects prognosis. © 2009 UICC
Alterations in miRNA processing and expression in pleomorphic adenomas of the salivary gland
Authors: Zhang Xiaoying , Cairns Murray , Rose Barbara , O'Brien Christopher , Shannon Kerwin , Clark Jonathan , Gamble Jennifer , Tran Nham 
Published: January 2009

AbstractGenome‐wide microRNA (miRNA) expression profiling of salivary gland pleomorphic adenomas revealed a distinct expression signature consisting largely of upregulated miRNAs compared with matched normal tissue. Microarray data were confirmed by quantitative real time RT‐PCR (q‐RTPCR). Five miRNA genes upregulated in the tumours were found in close proximity to fragile sites and/or cancer associated genomic regions. Interestingly, q‐RTPCR revealed an increase in the expression of components of the miRNA processing machinery (Dicer, Drosha, DGCR8 and p68) in tumours suggesting that the deregulation of miRNA expression may result from increased miRNA biogenesis. Target gene prediction analysis of the altered miRNAs indicated that genes in a number of signalling pathways important in tumourigenesis including WNT, MAPK and JAK‐STAT were overrepresented. Significantly, the oncogene PLAG1 was overexpressed in our cohort and may be potentially regulated by these miRNAs. This is the first study to examine changes in the miRNA milieu in pleomorphic adenoma, the most common salivary gland tumour. This study has demonstrated an upregulation of both miRNAs genes and an upregulation of the miRNA processing machinery. These changes may be potential underlying mechanisms for the development of these benign tumours. © 2009 UICC