bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrocatalytic Oxidation of Some Carbohydrates by Nickel/Poly(o‐Aminophenol) Modified Carbon Paste Electrode
Authors: Ojani Reza , Raoof Jahan‐Bakhsh , Fathi Shahla 
Published: July 2008

AbstractThis study investigates the electrocatalytic oxidation of glucose and some other carbohydrates on nickel/poly(o‐aminophenol) modified carbon paste electrode as an enzyme free electrode in alkaline solution. Poly(o‐aminophenol) was prepared by electropolymerization using a carbon paste electrode bulk modified with o‐aminophenol and continuous cyclic voltammetry in HClO4 solution. Then Ni(II) ions were incorporated to electrode by immersion of the polymeric modified electrode having amine group in 1 M Ni(II) ion solution. Cyclic voltammetric and chronoamperometric experiments were used for the electrochemical study of this modified electrode; a good redox behavior of Ni(OH)2/NiOOH couple at the surface of electrode can be observed, the capability of this modified electrode for catalytic oxidation of glucose and other carbohydrates was demonstrated. The amount of α and surface coverage (Γ*) of the redox species and catalytic chemical reaction rate constant (k) for each carbohydrate were calculated. Also, the electrocatalytic oxidation peak currents of all tested carbohydrates exhibit a good linear dependence on concentration and their quantification can be done easily.
Voltammetric Behavior of Trolox in Methanol and Ethanol Solutions
Authors: Karbarz Monika , Malyszko Jan 
Published: July 2008

AbstractElectrochemical oxidation of trolox on carbon electrodes was investigated by means of some voltammetric techniques in methanol and ethanol solutions in the presence of an excess of acid or base. The oxidation occurs according to EEC mechanism, i.e. in two quasireversible one‐electron steps yielding the corresponding phenoxyl radical and, subsequently, phenoxonium cation. Phenoxonium ion decays because of a pseudo‐first order follow‐up chemical reaction with nucleophiles. The electrochemical behavior of trolox is strongly influenced by the surrounding environmental conditions. In acidic solutions, a single two‐electron anodic wave was observed. The presence of a strong base drastically improves the stability of the intermediate, phenoxyl radical. Under these conditions, the two‐electron wave was found to split into its one‐electron components over a range of scan rates. The resolution is much distinct in ethanol. Simulations with DigiSim software were used to fit the cyclic voltammograms in order to estimate thermodynamic and kinetic data for the reaction mechanism studied.
Electrochemical Monitoring of DNA Hybridization by Multiwalled Carbon Nanotube Based Screen Printed Electrodes
Authors: Karadeniz Hakan , Erdem Arzum , Caliskan Ayfer 
Published: July 2008

AbstractThe application of multiwalled carbon nanotube (MWCNT) based screen printed graphite electrodes (SPEs) was explored in this study for the electrochemical monitoring of DNA hybridization related to specific sequences on Hepatitis B virus (HBV) DNA. After the microscopic characterization of bare MWCNT‐SPEs and DNA immobilized ones was performed, the optimization of assay has been studied. The development of screen printing process combined with nanomaterial based disposable sensor technology leads herein a great opportunity for DNA detection using differential pulse voltammetry (DPV) by measuring the guanine oxidation signal observed at +1.00 V in the presence of DNA hybridization between HBV probe and its complementary, target. The detection limit estimated for signal to noise ratios =3 corresponds to 96.33 nM target concentration in the 40 μL samples. The advantages of carbon nanotube based screen printed electrode used for electrochemical monitoring of DNA hybridization are discussed with sensitivity, selectivity and reproducibility in comparison with previous nanomaterial based electrochemical transducers developed for DNA or other biomolecular recognitions.
Influence of DNA repair gene polymorphisms on the initial repair of MMS‐induced DNA damage in human lymphocytes as measured by the alkaline comet assay
Authors: Ryk Charlotta , Routledge Michael N. , Allan James M. , Wild Christopher P. , Kumar Rajiv , Lambert Bo , Hou Saimei 
Published: July 2008

AbstractWe have applied the alkaline comet assay to study the functional impact of gene polymorphisms in base excision repair (APEX1 Asp148Glu, XRCC1 Arg194Trp, XRCC1 Arg399Gln) and homologous recombination repair (XRCC3 Thr241Met, NBS1 Glu185Gln), two pathways that play crucial roles in the repair of DNA damage induced by methylmethane sulphonate (MMS). We also examined the effect of polymorphisms in mismatch repair (MLH1 −93 A/G) and nucleotide excision repair (XPD Lys751Gln) as putative negative controls based on the limited roles of these pathways in MMS‐induced repair. Phytohemagglutinin‐stimulated peripheral lymphocytes from 52 healthy individuals were treated with MMS and allowed to repair for 0, 15, 40, or 120 min after a 6‐min washing step. DNA damage was measured as a pseudo‐percentage score (comparable to % tail DNA) converted from a total visual score calculated from the distribution of cells with different degrees of damage (normal, mild, moderate and severe). The repair was faster at the beginning of the observation period than towards the end, and was not complete after 2 hr. Presence of the APEX1 148Asp, XRCC3 241Met or NBS1 185Gln alleles were significantly associated with a high pseudo‐percentage score (above median) at early time points, with the APEX1 effect being most prolonged (up to 40 min after washing, odds ratio 5.6, 95% confidence interval 2.0–15.5). No significant effects were seen with the XRCC1 Arg194Trp, XRCC1 Arg399Gln, MLH1 −93A/G and XPD Lys751Gln polymorphisms. Our results provide evidence for the functional nature of the variant alleles studied in the APEX1, XRCC3, and NBS1 genes. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Comparison of metabolite profiles generated in Aroclor‐induced rat liver and human liver subcellular fractions: Considerations for in vitro genotoxicity hazard assessment
Authors: Obach R. Scott , Dobo Krista L. 
Published: July 2008

AbstractBecause it is well known that metabolites of chemicals and drugs are frequently the ultimate species responsible for genotoxicity and carcinogenicity, in vitro testing to identify the human genotoxicity hazard potential of new chemicals and drugs routinely utilizes liver S‐9 fraction from rats treated with Aroclor 1254 as a system that can generate metabolites. However, it is frequently questioned as to whether such an in vitro metabolite generation system is the most relevant for human risk, or whether the assay would be better served by using a human‐derived in vitro system. To address this, 16 common drugs have been examined for profiles of metabolites in Aroclor‐induced rat liver S‐9 and pooled human liver S‐9. Metabolite profiles were compared using high pressure liquid chromatography coupled with ion trap mass spectrometry, in line with ultraviolet or radiometric detection to help make semiquantitative comparisons. Results showed that, with few exceptions, metabolites generated in the human system were also generated in the rat system. Also, in several cases the rat system generated considerably more metabolites, suggesting that there is a potential that positive genotoxicity findings could be caused by metabolites that have no relevance to humans. These findings suggest that when conducting in vitro genotoxicity testing using the Aroclor‐induced rat liver S‐9 system, knowledge of the metabolite profile in the system is important, and a comparison to the profile generated in human liver S‐9 could be of value when interpreting the genotoxicity results. Environ. Mol. Mutagen., 2008. © 2008 Wiley‐Liss, Inc.
Comparative study of Euler/Euler and Euler/Lagrange approaches simulating evaporation in a turbulent gas–liquid flow
Authors: Groll R. , Jakirlić S. , Tropea C. 
Published: July 2008

AbstractThis study deals with the Reynolds‐averaged Navier–Stokes simulation of evaporation in a turbulent gas–liquid flow in a three‐dimensional duct, focussing on the results obtained by a four‐equation turbulence model within the framework of the Euler/Euler approach for multiphase flow calculations: in addition to the two‐equation k−ε model describing the turbulence of the continuous (C) phase, the computational model employs transport equations for the turbulence kinetic energy of the disperse (D) phase and for the velocity covariance q=〈{u}D{u}C〉D. In the present study, the evaporation model according to Abramzon and Sirignano (Int. J. Heat Mass Transfer 1989; 32:1605–1618) has been extended by introducing an additional transport equation for a newly defined quantity ā, defined as the phase‐interface surface fraction. This allows the change in the drop diameter to be quantified in terms of a probability density function. The source term in the equation describing the dynamics of the volumetric fraction of the dispersed phase αD is related to the evaporation time scale τΓ. The performance of the new model is evaluated by performing a comparative analysis of the results obtained by simulating a polydispersed spray in a three‐dimensional duct configuration with the results of the Euler/Lagrange calculations performed in parallel. Prior to these calculations, some selected (solid) particle‐laden flow configurations were computationally examined with respect to the validation of the background, four‐equation, eddy‐viscosity‐based turbulence model. Copyright © 2008 John Wiley & Sons, Ltd.
Histone deacetylase 11 regulates oligodendrocyte‐specific gene expression and cell development in OL‐1 oligodendroglia cells
Authors: Liu Hedi , Hu Qichen , D'ercole A. Joseph , Ye Ping 
Published: July 2008

AbstractBoth in vivo and in vitro studies indicate a correlation between reduced acetylation of histone core proteins and oligodendrocyte development. The nature of these histone modifications and the mechanisms mediating them remain undefined. To address these issues, we utilized OL‐1 cells, a rat nontransformed oligodendrocyte cell line, and primary oligodendrocyte cultures. We found that the acetylated histone H3 at lysine 9 and lysine 14 (H3K9/K14ac) is reduced in both the myelin basic protein (MBP) and proteolipid protein (PLP) genes of maturing oligodendroglial OL‐1 cells, and furthermore, this temporally correlates with increases in MBP, PLP, and histone deacetylase (HDAC) 11 expression. Disruption of developmentally‐regulated histone H3 deacetylation within the MBP and PLP genes by the HDAC inhibitor trichostatin A blunts MBP and PLP expression. With its increased expression, interaction of HDAC 11 with acetylated histone H3 and recruitment of HDAC 11 to the MBP and PLP genes markedly increases in maturing OL‐1 cells. Moreover, suppressing HDAC 11 expression with small interfering RNA significantly (1) increases H3K9/K14ac globally and within the MBP and PLP genes, (2) decreases MBP and PLP mRNA expression, and (3) blunts the morphological changes associated with oligodendrocyte development. Our data strongly support a specific role for HDAC 11 in histone deacetylation and in turn the regulation of oligodendrocyte‐specific protein gene expression and oligodendrocyte development. © 2008 Wiley‐Liss, Inc.
Sedation and antihistamines: an update. Review of inter‐drug differences using proportional impairment ratios
Authors: McDonald Kathleen , Trick Leanne , Boyle Julia 
Published: July 2008

AbstractBackgroundThe use of antihistamines (AHs) has been associated with cognitive and psychomotor impairments, largely caused by the sedative properties of many of these drugs. Due to the ambulant nature of the population using AHs, it is important to evaluate these effects using standardised methodology and psychometric tests. A previous extensive review of the literature collated the results of studies of H1 receptor antagonists to determine the extent to which a particular AH produced impairments on a battery of psychometric tests by calculating a proportional impairment ratio for each AH.ObjectiveIn light of a number of major studies published following the previous review, and the development of the second and new‐generation AHs, the present review aims to add to the database and update the review, using the same methodology.Results and ConclusionThe newer generation AHs appear to be the least impairing, and the first generation, as expected, appear to be the most impairing. There are also differences within the AH drug generations. The review highlights the necessity to consider the sedating potential of AHs, along with other factors such as efficacy, when prescribing AHs to ambulant patients. Copyright © 2008 John Wiley & Sons, Ltd.
Pesticide exposure as risk factor for non‐Hodgkin lymphoma including histopathological subgroup analysis
Authors: Eriksson Mikael , Hardell Lennart , Carlberg Michael , Åkerman Måns 
Published: July 2008

AbstractWe report a population based case–control study of exposure to pesticides as risk factor for non‐Hodgkin lymphoma (NHL). Male and female subjects aged 18–74 years living in Sweden were included during December 1, 1999, to April 30, 2002. Controls were selected from the national population registry. Exposure to different agents was assessed by questionnaire. In total 910 (91 %) cases and 1016 (92%) controls participated. Exposure to herbicides gave odds ratio (OR) 1.72, 95% confidence interval (CI) 1.18–2.51. Regarding phenoxyacetic acids highest risk was calculated for MCPA; OR 2.81, 95% CI 1.27–6.22, all these cases had a latency period >10 years. Exposure to glyphosate gave OR 2.02, 95% CI 1.10–3.71 and with >10 years latency period OR 2.26, 95% CI 1.16–4.40. Insecticides overall gave OR 1.28, 95% CI 0.96–1.72 and impregnating agents OR 1.57, 95% CI 1.07–2.30. Results are also presented for different entities of NHL. In conclusion our study confirmed an association between exposure to phenoxyacetic acids and NHL and the association with glyphosate was considerably strengthened. © 2008 Wiley‐Liss, Inc.
Caspase‐3 enhances lung metastasis and cell migration in a protease‐independent mechanism through the ERK pathway
Authors: Cheng Yu‐Jung , Lee Chien‐hsin , Lin Yu‐Ping , Huang Jyun‐Yuan , Su Chung‐Chen , Chang Wen‐Tsan , Yang Bei‐Chang 
Published: July 2008

AbstractCaspase‐3 is known as a cysteine protease that primarily executes the cell death program. However, some tumors express higher levels of caspase‐3 in positive correlation with malignancy. Here, we showed that caspase‐3 can promote tumor metastasis in a protease‐independent mechanism. Ectopic expression of caspase‐3 enhanced lung metastasis and cell motility of caspase‐3 deficient MCF‐7 cells. By contrast, caspase‐3 siRNA reduced the invasiveness and metastasis ability of A549 cells that express high level of caspase‐3. Moreover, caspase‐3 induced ERK activation. Alteration of caspase‐3 by introducing non‐processable mutation at its cleavage site or treatment of caspase‐3 inhibitor did not diminish the caspase‐3‐associated increases in ERK phosphorylation and cell migration. Confocal microscopy study showed that caspase‐3 was not physically associated with ERK. Inhibiting ceramide formation by blockage of the ceramide synthase or acid sphingomyelinase activity resulted in significant reduction of ERK phosphorylation and cell migration. In summary, caspase‐3 induces ERK activation through a ceramide‐dependant, protease activity‐independent mechanism, which represents a novel role of caspase‐3 in tumor metastasis. © 2008 Wiley‐Liss, Inc.
IGF1 is a modifier of disease risk in hereditary non‐polyposis colorectal cancer
Authors: Reeves Stuart G. , Rich Dominique , Meldrum Cliff J. , Colyvas Kim , Kurzawski Grzegorz , Suchy Janina , Lubinski Jan , Scott Rodney J. 
Published: July 2008

AbstractPatients diagnosed with HNPCC harbouring a confirmed germline mutation in DNA mismatch repair (MMR) genes have an 80% lifetime risk of developing an epithelial malignancy. There is, however, considerable variation in the age of disease onset in these patients. Insulin‐like growth factor‐I (IGFI) has been implicated in colorectal cancer (CRC), and elevated plasma IGFI levels are associated with both sporadic and hereditary CRC risk. In this study, we further investigate the cytosine‐adenine (CA) dinucleotide repeat polymorphism located near the promoter region of IGF1 and its relation to early onset CRC risk in 443 Australian and Polish MMR gene mutation carriers using DNA sequencing, Kaplan‐Meier survival curves and Cox proportional hazard regression analysis. A significantly smaller number of IGF1 CA repeats was observed in the Polish patient population, which was associated with an earlier age of disease onset compared to the Australian patients. The threshold for the observed modifying effect was again shown to be in patients with 17 or less CA repeats compared to those with 18 or more. Furthermore, when MMR mutation group (i.e., MLH1 or MSH2), gender and family clustering were included in the final Cox model we observed a more robust trend for the role of the IGF1 CA repeat in predicting age of disease onset in HNPCC patients. In addition, this effect was shown to be equal in both MLH1 and MSH2 mutation carrier groups and not restricted to a particular MMR subgroup (p = 0.001). We conclude that the IGF1 CA repeat is an important modifier of disease onset in HNPCC and the first polymorphism to yield consistent results across different populations. © 2008 Wiley‐Liss, Inc.
Folate deprivation induces BCRP (ABCG2) expression and mitoxantrone resistance in Caco‐2 cells
Authors: Lemos Clara , Kathmann Ietje , Giovannetti Elisa , Dekker Henk , Scheffer George L. , Calhau Conceição , Jansen Gerrit , Peters Godefridus J. 
Published: July 2008

AbstractFolates can induce the expression and activity of the breast‐cancer‐resistance‐protein (BCRP) and the multidrug‐resistance‐protein‐1 (MRP1). Our aim was to study the time‐dependent effect of folate deprivation/supplementation on (i) BCRP and MRP expression and (ii) on drug resistance mediated by these transporters. Therefore Caco‐2 colon cancer cells usually grown in standard RPMI‐medium containing supraphysiological folic acid (FA) concentrations (2.3 μM; high‐folate, HF) were gradually adapted to more physiological folate concentrations (1 nM leucovorin (LV) or 1 nM FA; low‐folate, LF), resulting in the sublines Caco‐2‐LF/LV and Caco‐2‐LF/FA. Caco‐2‐LF/LV and LF/FA cells exhibited a maximal increase of 5.2‐ and 9.6‐fold for BCRP‐mRNA and 3.9‐ and 5.7‐fold for BCRP protein expression, respectively, but no major changes on MRP expression. Overexpression of BCRP in the LF‐cells resulted in 3.6‐ to 6.3‐fold resistance to mitoxantrone (MR), which was completely reverted by the BCRP inhibitor Ko143. On the other hand, LF‐adapted cells were markedly more sensitive to methotrexate than the HF‐counterpart, both after 4‐hr (9,870‐ and 23,923‐fold for Caco‐2‐LF/LV and LF/FA, respectively) and 72‐hr (11‐ and 22‐fold for Caco‐2‐LF/LV and LF/FA, respectively) exposure. Immunofluorescent staining observed with a confocal‐laser‐scan‐microscope revealed that in Caco‐2 cells (both HF and LF), BCRP is mainly located in the cytoplasm. In conclusion, folate deprivation induces BCRP expression associated with MR resistance in Caco‐2 cells. The intracellular localization of BCRP in these cells suggests that this transporter is not primarily extruding its substrates out of the cell, but rather to an intracellular compartment where folates can be kept as storage. © 2008 Wiley‐Liss, Inc.
The Ikaros splice isoform, Ikaros 6, immortalizes murine haematopoietic progenitor cells
Authors: Ruiz Anna , Williams Owen , Brady Hugh J.M. 
Published: July 2008

AbstractAlternative pre‐mRNA splicing is emerging as a major control point in both the initiation and progression of tumourigenesis. Overexpression of the dominant negative Ikaros splice isoform, Ik6, is found in many human cancers particularly leukaemias. Ik6 has been demonstrated to have a role in cell survival in both myeloid‐ and lymphoid cytokine‐dependent cell lines. To investigate the oncogenic potential of Ik6, we retrovirally transduced murine haematopoietic progenitor cells with Ik6 and have analysed the effects on proliferation and differentiation of these precursors using myeloid and lymphoid in vitro colony formation assays. We found that Ik6 can immortalize haematopoietic progenitor cells in myeloid conditions. Using an in vivo transplantation assay, we found that Ik6 favours reconstitution by haematopoietic precursors. These findings suggest that Ik6 may play an important role in the generation of the leukaemic phenotype. © 2008 Wiley‐Liss, Inc.
Impact of antioxidant supplementation on chemotherapeutic toxicity: A systematic review of the evidence from randomized controlled trials
Authors: Block Keith I. , Koch Amanda C. , Mead Mark N. , Tothy Peter K. , Newman Robert A. , Gyllenhaal Charlotte 
Published: July 2008

AbstractMuch debate has focused on whether antioxidants interfere with the efficacy of cancer chemotherapy. The objective of this study is to systematically review the randomized, controlled clinical trial evidence evaluating the effects of concurrent use of antioxidants with chemotherapy on toxic side effects. We performed a search of literature from 1966‐October 2007 using MEDLINE, Cochrane, CinAhl, AMED, AltHealthWatch and EMBASE databases. Randomized, controlled clinical trials reporting antioxidant‐based mitigation of chemotherapy toxicity were included in the final tally. Searches were performed following a standardized protocol for systematic reviews. Only 33 of 965 articles considered, including 2,446 subjects, met the inclusion criteria. Antioxidants evaluated were: glutathione (11), melatonin (7), vitamin A (1), an antioxidant mixture (2), N‐acetylcysteine (2), vitamin E (5), selenium (2), L‐carnitine (1), Co‐Q10 (1) and ellagic acid (1). The majority (24) of the 33 studies included reported evidence of decreased toxicities from the concurrent use of antioxidants with chemotherapy. Nine studies reported no difference in toxicities between the 2 groups. Only 1 study (vitamin A) reported a significant increase in toxicity in the antioxidant group. Five studies reported the antioxidant group completed more full doses of chemotherapy or had less‐dose reduction than control groups. Statistical power and poor study quality were concerns with some studies. This review provides the first systematically reviewed evidence that antioxidant supplementation during chemotherapy holds potential for reducing dose‐limiting toxicities. However, well‐designed studies evaluating larger populations of patients given specific antioxidants defined by dose and schedule relative to chemotherapy are warranted. © 2008 Wiley‐Liss, Inc.