bluuebunny/crossref_metadata_2025_split huggingface dataset:
G‐Quadruplex DNA Structures and Organic Chemistry: More Than One Connection (Eur. J. Org. Chem. 14/2009)
Authors: Franceschin Marco 
Published: April 2009

AbstractThe cover picture shows the monomeric G‐quadruplex structure of the 22‐mer human telomeric DNA sequence AGGG(TTAGGG)3 derived by X‐ray crystallography in Neidle?s group (G. N. Parkinson, M. P. Lee, S. Neidle, Nature 2002, 417, 876) in a potassium ion solution (PDB code 1KF1). The molecular graphic was produced by using the UCSF Chimera package from the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco (supported by NIH P41 RR‐01081). The DNA backbone is in cyan, covered by a semitransparent meshed surface; K+ ions are represented by violet spheres, and a yellow ribbon follows the strand topology. The four arrows indicate the related main areas of interest for organic chemists: design and synthesis of G‐quadruplex ligands, study of ligand interactions with quadruplex and duplex DNA, quadruplex‐forming modified oligonucleotides and nanostructures based on the G‐quadruplex. In the background, the structures of some well‐known G‐quadruplex ligands, based on perylene, coronene, berberine, porphyrin and acridine moieties, are shown in yellow, as well as the natural compound telomestatin. Details are presented in the Microreview by M. Franceschin on p. 2225 ff.
A Review: Electrochemical Aptasensors with Various Detection Strategies
Authors: Xu Ying , Cheng Guifang , He Pingang , Fang Yuzhi 
Published: April 2009

AbstractThe combinatorial chemical synthesis offers in vitro aptamer generation with limitless aptamer selection for various analytes. Additionally, aptamer has quite many outstanding properties as the biomolecular recognition elements, thus competing with traditional affinity ligands (enzyme, antibodies, lectins etc.) in biological and medicine employments. This article reviews the advancements in electrochemical aptasensors for biomolecule monitoring, emphasizing the efficient detection strategies of sandwich structure formation using two recognition elements to capture and label target respectively, EIS measuring the electronic transfer resistance change, the aptamer conformation change triggering the electrochemical signal on/off and target molecules displacing electroactive markers.
A Simple and Sensitive Biosensor Based on Silver Enhancement of Aptamer‐Gold Nanoparticle Aggregation
Authors: Zhang Zhen , Chen Chunlai , Sheng Zhao Xin 
Published: April 2009

AbstractWe have found that dispersed gold nanoparticles (AuNPs) have higher silver enhancement than that of aggregated AuNPs. Based on this observation we propose a general methodology of assay, the silver enhancement of aptamer‐gold nanoparticle aggregation (SEAGNA). The assay is simple, inexpensive, fast, and sensitive. Adenosine aptamer is used to demonstrate the essence of this method. A tiny amount of sample is enough, and 0.1 pmol (0.1 μM in 1 μL) of adenosine can be detected with naked eyes. The sensitivity of most existing AuNPs‐based colorimetric biosensors can be easily improved by applying our silver enhancement.
The role of paraoxonase polymorphisms in the induction of micronucleus in paraoxon‐treated human lymphocytes
Authors: Rojas‐García Aurora E. , Sordo Monserrat , Vega Libia , Quintanilla‐Vega Bezabet , Solis‐Heredia Maria , Ostrosky‐Wegman Patricia 
Published: April 2009

AbstractHuman paraoxonase‐1 (PON1) is a high‐density lipoprotein‐associated enzyme that has a role in the detoxification of organophosphorus compounds by hydrolyzing the bioactive oxons. PON1 polymorphims are responsible, at least in part, for the variation in the catalytic activity and expression of the enzyme and have been associated with susceptibility to organophosphorus pesticide toxicity, mainly neurotoxicity. The aim of this study was to determine whether paraoxon induced micronuclei and to examine the role of PON1 polymorphism in paraoxon's genotoxic potential. First, dose finding cytogenetic experiments were performed on lymphocyte cultures from three donors and a range of paraoxon concentration (1–25 μM) were tested. In a second set of experiments, 5 μM paraoxon was added to blood cultures of 11 donors with two different PON1 haplotypes (PON T−108M55Q192 with low activity and haplotype PON C−108L55 R192 with high activity, referred to as PON1QQ and as PON1 RR, respectively). Because PON1 is present in blood, the effect of adding 5 μM paraoxon and 70 μl of autologous plasma to lymphocyte cultures also was examined. Paraoxon had no effect on cell viability, but caused a significant dose‐dependent increase in MN frequency. The basal MN frequencies were similar on QQ and RR genotypes. A significant difference was observed in the MN frequency only in lymphocytes from individuals with the QQ genotype treated with 5 μM paraoxon and the autologous plasma did not modify these effects. The results obtained in this study suggest that PON1 genotype might have an important role in the identification of individuals at risk for cancer development due to occupational exposure to pesticides. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Effect of annatto on micronuclei induction by direct and indirect mutagens in HepG2 cells
Authors: Barcelos Gustavo Rafael Mazzaron , Angeli José Pedro Friedmann , Serpeloni Juliana Mara , Rocha Bruno Alves , Mantovani Mário Sérgio , Antunes Lusânia Maria Greggi 
Published: April 2009

AbstractAnnatto (AN), a natural food colorant rich in carotenoids, has been reported as being an effective antioxidant, but little is known about its potential chemopreventive properties. In this study, we evaluated the ability of AN to protect human hepatoma cells (HepG2) from micronucleus (MN) induction against three different mutagens: benzo(a)pyrene (B(a)P), doxorubicin (DXR), and methyl methanesulfonate (MMS). In an attempt to clarify the possible mechanism of antimutagenicity of AN, three protocols of treatment were applied (pretreatment; simultaneous treatment, and post‐treatment with AN following treatment with the mutagens). Also, cells exposed only to AN were assayed for cytotoxicity and mutagenicity. A dosage up to 10 μg/ml of AN was devoid of mutagenic activity. Protective effects were seen on micronuclei induced by B(a)P and DXR using pre and simultaneous treatment, but AN had no significant effect on MN induction by MMS in any of the protocols. Our results also show that exposure of cells to concentrations of AN higher than 10 μg/ml decreased cell viability. Taken together, our findings indicate that AN presents antimutagenic activity in vitro, but its protective effect is dependent on the mutagen and on type of treatment suggesting its potential use as a chemopreventive agent. Environ. Mol. Mutagen. 2009. © 2009 Wiley‐Liss, Inc.
Correlation model for spatially distributed ground‐motion intensities
Authors: Jayaram Nirmal , Baker Jack W. 
Published: April 2009

AbstractRisk assessment of spatially distributed building portfolios or infrastructure systems requires quantification of the joint occurrence of ground‐motion intensities at several sites, during the same earthquake. The ground‐motion models that are used for site‐specific hazard analysis do not provide information on the spatial correlation between ground‐motion intensities, which is required for the joint prediction of intensities at multiple sites. Moreover, researchers who have previously computed these correlations using observed ground‐motion recordings differ in their estimates of spatial correlation. In this paper, ground motions observed during seven past earthquakes are used to estimate correlations between spatially distributed spectral accelerations at various spectral periods. Geostatistical tools are used to quantify and express the observed correlations in a standard format. The estimated correlation model is also compared with previously published results, and apparent discrepancies among the previous results are explained.The analysis shows that the spatial correlation reduces with increasing separation between the sites of interest. The rate of decay of correlation typically decreases with increasing spectral acceleration period. At periods longer than 2 s, the correlations were similar for all the earthquake ground motions considered. At shorter periods, however, the correlations were found to be related to the local‐site conditions (as indicated by site Vs30 values) at the ground‐motion recording stations. The research work also investigates the assumption of isotropy used in developing the spatial correlation models. It is seen using the Northridge and Chi‐Chi earthquake time histories that the isotropy assumption is reasonable at both long and short periods. Based on the factors identified as influencing the spatial correlation, a model is developed that can be used to select appropriate correlation estimates for use in practical risk assessment problems. Copyright © 2009 John Wiley & Sons, Ltd.
Multi‐scale simulation with a hybrid Boussinesq‐RANS hydrodynamic model
Authors: Sitanggang K. I. , Lynett P. J. 
Published: April 2009

AbstractA hybrid wave model is developed for simulation of water wave propagation from deep water to shoreline. The constituent wave models are the irrotational, 1‐D horizontal Boussinesq and 2‐D vertical Reynolds‐averaged Navier–Stokes (RANS). The models are two‐way coupled, and the interface is placed at a location where turbulence is relatively small. Boundary conditions on the interfacing side of each model are provided by its counterpart model through data exchange. Prior to the exchange, a data transformation step is carried out due to the differences in physical variables and approximations employed in both models. The hybrid model is tested for both accuracy and speedup performance. Tests consisting of idealized solitary and standing wave motions and wave overtopping of nearshore structures show that: (1) the simulation results of the current hybrid model compare well with the idealized data, experimental data, and pure RANS model results and (2) the hybrid model saves computational time by a factor proportional to the reduction in the size of the RANS model domain. Finally, a large‐scale tsunami simulation is provided for a numerical setup that is practically unapproachable using RANS model alone; not only does the hybrid model offer more rapid simulation of relatively small‐scale problems, it provides an opportunity to examine very large total domains with the fine resolution typical of RANS simulations. Copyright © 2009 John Wiley & Sons, Ltd.
Greater leftward lateralization of the inferior frontal gyrus in second language learners with higher syntactic abilities
Authors: Nauchi Arihito , Sakai Kuniyoshi L. 
Published: April 2009

AbstractThere is a great individual variability for acquiring syntactic knowledge in a second language (L2). Little is, however, known if there is any anatomical basis in the brain for individual differences in syntactic acquisition. Here we examined brain structures in 95 nonnative speakers of English, including 78 high‐school students and 17 adult international students. We found a significant correlation between the performance of a syntactic task and leftward lateralization of a single region in the triangular part (F3t) of the inferior frontal gyrus, which has been proposed as the grammar center. Moreover, this correlation was independent of the performance of a spelling task, age, gender, and handedness. This striking result suggests that the neural basis for syntactic abilities in L2 is independent of that for lexical knowledge in L2, further indicating that the individual differences in syntactic acquisition are related to the lateralization of the grammar center. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Sequence dependence of cell growth inhibition by EGFR–tyrosine kinase inhibitor ZD1839, docetaxel, and cisplatin in head and neck cancer
Authors: Klass Carmen M. , Choe Mi Sun , Hurwitz Selwyn J. , Tighiouart Mourad , Zhang Xin , Chen Zhuo (Georgia) , Shin Dong M. 
Published: April 2009

AbstractBackgroundThis study was to explore whether the efficacy of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor ZD1839 (Z, Iressa, gefitinib) plus chemotherapeutic agents docetaxel (D) and cisplatin (P) may benefit from sequencing of the combination.MethodsThree head and neck cancer cell lines were used to study the effect of various combinations of and relative sequencing of D, P, and Z in cell growth inhibition. A population pharmacokinetic stimulation study was conducted on Z in silico and used together with the growth inhibition data to derive principles for future in vivo use of this drug combination.ResultsThe inhibitory effects of Z on combinations of D and P were sequence dependent. Treatment simultaneously with DPZ or with DP followed by Z (DP→Z) showed synergistic effects in all 3 cell lines. However, sequencing with Z followed by DP (Z→DP), gave an antagonistic effect, suggesting that D and P should be administered when the effect of Z is low. The induction of apoptosis was also sequence dependent. The in silico pharmacokinetic study suggested the feasibility of deriving a 5‐day‐on/2‐day‐off regimen for Z, in which D and P administration commences when levels of Z are low, allowing levels of Z to accumulate sufficiently during the remainder of the cycle.ConclusionThese data suggests that it is feasible to design clinical trials with these settings to maximize the efficacy of this combined drug regimen. © 2009 Wiley Periodicals, Inc. Head Neck, 2009
CD24 polymorphisms affect risk and progression of chronic hepatitis B virus infection #
Authors: Li Dongling , Zheng Linghua , Jin Lei , Zhou Yuesu , Li Haiying , Fu Junliang , Shi Ming , Du Peishuang , Wang Lizhong , Wu Hao , Chen Guo-Yun , Zheng Pan , Liu Yang , Wang Fu-Sheng , Wang Shengdian 
Published: April 2009

Abstract
T-cell immunity to hepatitis B virus (HBV) is involved in both viral clearance and the pathogenesis of cirrhosis and hepatocellular carcinoma following chronic HBV infection. It is therefore of great interest to analyze whether genetic polymorphism of genes involved in the immune response may determine the outcomes of chronic HBV infection. Here we report that CD24 polymorphisms affect the risk and progression of chronic HBV infection. Thus the CD24 P170
T
allele, which is expressed at a higher level, is associated with an increased risk of chronic HBV infection. Among the chronic HBV patients this allele shows recessive association with more rapid progression to liver cirrhosis and hepatocellular carcinoma in comparison to the P170
C
allele. In contrast, a dinucleotide deletion at position 1527–1528 (P1527
del
), which reduces CD24 expression, is associated with a significantly reduced risk of chronic HBV infection. To confirm the role for CD24 in liver carcinogenesis, we compared the size of liver tumor developed in CD24−/− and CD24+/− HBV transgenic mice. Our data demonstrate that targeted mutation of CD24 drastically reduced the sizes of spontaneous liver cancer in the HBV transgenic mice. Conclusion: These data demonstrate that genetic variation of CD24 may be an important determinant for the outcome of chronic HBV infection. (Hepatology 2009.)
Incidence of cancer and statin usage—Record linkage study
Authors: Haukka Jari , Sankila Risto , Klaukka Timo , Lonnqvist Jouko , Niskanen Leo , Tanskanen Antti , Wahlbeck Kristian , Tiihonen Jari 
Published: April 2009

AbstractThe consumption of statins (HMG‐CoA reductase inhibitors) has been increasing, and a substantial part of the middle‐aged and elderly population use them continuously. Because a large fraction of the population is exposed, even a small excess of risk with respect to cancer should be considered. We carried out a record‐linkage study in Finland utilizing nationwide databases of reimbursed statin medication and cancer. The study population included all statin users in Finland who had purchased at least 1 prescription between 1996 and 2005 and who had no cancer diagnosis at the date of first purchase. A control population without statin usage was also included. Data consisted of 472,481 pairs of individuals that cumulated 4.2 million person years with an average of 8.8 years of follow‐up. Fifty thousand two hundred ninety‐four cancer cases were observed. Simvastatin and atorvastatin were the most used substances. The most frequent cancers were prostate, breast, lung, colon, and rectum cancer. In general, no association between the utilization of statins and cancer could be detected. In conclusion, this study adds large‐scale, population‐based results about the association between statin utilization and the incidence of cancer. We found neither beneficial nor harmful associations between the usage of statins and cancer.
EGFRvIII‐induced estrogen‐independence, tamoxifen‐resistance phenotype correlates with PgR expression and modulation of apoptotic molecules in breast cancer
Authors: Zhang Yang , Su Hua , Rahimi Massod , Tochihara Ryan , Tang Careen 
Published: April 2009

AbstractThe tumor‐specific, ligand‐independent, constitutively active epidermal growth factor receptor (EGFR) variant, EGFRvIII, remains understudied in breast cancer. Here, we report that expression of EGFRvIII in the ErbB‐2‐overexpressing, estrogen‐dependent MDA‐MB‐361 breast cancer cell line resulted in significant estrogen‐independent tumor growth in ovariectomized, athymic nude mice in comparison to MDA‐MB‐361/wt cells. MDA‐MB‐361/vIII breast cancer cells maintained estrogen‐induced tumor growth, but were tamoxifen‐resistant in the presence of estrogen, while MDA‐MB‐361/wt cells had a significant reduction in tumor growth in the presence of estrogen and tamoxifen. Tamoxifen alone did not have a significant effect on EGFRvIII‐mediated estrogen‐independent tumor growth. Constitutive signaling from the EGFRvIII receptor resulted in an increased activation of both the Akt and MAPK pathways. Compared to estrogen‐dependent, tamoxifen‐sensitive MCF‐7/vIII breast cancer cells, which had unchanged levels of ERα, but an increase in progesterone receptor (PgR) in comparison to MCF‐7/wt cells, MDA‐MB‐361/vIII cells had a reduction in ERα expression as well as a more pronounced reduction in PgR compared with MDA‐MB‐361/wt cells. EGFRvIII expression was also significantly associated with an absence of PgR protein in invasive human breast cancer specimens. Alterations of proapoptotic proteins and antiapoptotic proteins were observed in EGFRvIII transfectants. In conclusion, constitutive signaling through EGFRvIII and its downstream effector proteins crosstalks with the ERα pathway, resulting in loss of PgR expression and alterations in the apoptotic pathway, which may result in the estrogen‐independent, tamoxifen‐resistant phenotype conferred to EGFRvIII‐expressing breast cancer cells. © 2009 UICC
Reduced expression and homozygous deletion of annexin A10 in gastric carcinoma
Authors: Kim Jin , Kim Min A , Jee Chang Do , Jung Eun Ji , Kim Woo Ho 
Published: April 2009

AbstractAnnexins (ANXs) are a family of calcium and phospholipid binding proteins that have been implicated in diverse important biological and physiological process. ANX A10 (ANXA10) is a member of this family, though little is known about its functions. In the present study, array based comparative genomic hybridization (CGH) was used to screen DNA copy number change in gastric cancer cell lines and the results obtained were compared with oligonucleotide microarray data. DNA loss of the ANXA10 locus in chromosome 4q33 was found in several gastric cancer cell lines by array based CGH and these cell lines showed decreased ANXA10 expression by oligonucleotide microarray analysis. Functional analysis using siRNA and full‐length cDNA transfection in gastric cancer cell lines demonstrated that ANXA10 regulates gastric cancer cell proliferation. Of the 585 primary gastric carcinoma tissues examined, ANXA10 expression at the protein level was found to be reduced in 289 (49.4%) cases. Quantitative real‐time PCR analysis validated loss of DNA at the ANXA10 locus in gastric carcinomas with reduced ANXA10 expression. By univariate survival analysis, lack of ANXA10 expression was associated with poor survival (p = 0.016). These results suggest that ANXA10 inactivation by chromosomal deletion may play a role during gastric cancer progression. © 2009 UICC
Effect of bone sialoprotein coating of ceramic and synthetic polymer materials on in vitro osteogenic cell differentiation and in vivo bone formation
Authors: Schaeren Stefan , Jaquiéry Claude , Wolf Francine , Papadimitropoulos Adam , Barbero Andrea , Schultz‐Thater Elke , Heberer Michael , Martin Ivan 
Published: April 2009

AbstractIn this study, we addressed whether Bone Sialoprotein (BSP) coating of various substrates could enhance the in vitro osteogenic differentiation and in vivo bone formation capacity of human Bone Marrow Stromal Cells (BMSC). Moreover, we tested whether synthetic polymer‐based porous scaffolds, despite the absence of a mineral component, could support ectopic bone formation by human BMSC if coated with BSP. Adsorption of recombinant human BSP on tissue culture‐treated polystyrene (TCTP), β‐tricalcium phosphate (Osteologic™) or synthetic polymer (Polyactive™) substrates was dose dependent, but did not consistently accelerate or enhance in vitro BMSC osteogenic differentiation, as assessed by the mRNA expression of osteoblast‐related genes. Similarly, BSP coating of porous β‐tricalcium phosphate scaffolds (Skelite™) did not improve the efficiency of bone tissue formation following loading with BMSC and ectopic implantation in nude mice. Finally, Polyactive™ foams seeded with BMSC did not form bone tissue in the same ectopic assay, even if coated with BSP. We conclude that BSP coating of a variety of substrates is not directly associated with an enhancement of osteoprogenitor cell differentiation in vitro or in vivo, and that presentation of BSP on polymeric materials is not sufficient to prime BMSC functional osteoblastic differentiation in vivo. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Size‐tunable synthesis of stable superparamagnetic iron oxide nanoparticles for potential biomedical applications
Authors: Yu Faquan , Yang Victor C. 
Published: April 2009

AbstractDextran‐coated superparamagnetic nanoparticles (MNPs) have widespread biomedical applications. The superparamagnetic behavior, specifically regulated size, and smooth morphology are crucial requirements for essentially all of these applications. Presented herein is an innovative double‐coating strategy that would allow for a size‐controlled synthesis of MNPs. Small monocrystalline iron oxide nanoparticles (MIONs) were first synthesized, which served as the source of superparamagnetic properties. These MIONs were then treated in an acetate buffer containing biocompatible dextran polymer. Under such an environment, the colloidal MIONs would be quickly agglomerated by the acetate ions, and the formed coalescent body of MION would then be stabilized simultaneously by coating with dextran. By regulating the MION or dextran concentration as well as the thermal incubation time, the sizes of these first formed nanoparticles (termed 1st‐NPs) could be readily controlled. A second dextran coating step was further applied to smoothen the 1st‐NPs in attaining a final product (termed 2nd‐NPs). The 2nd‐NPs exhibited robust storage stability because of the additional coating shell. Results successfully confirmed the plausibility of this approach, as these MNPs displayed not only a smooth outline and a narrow size distribution but also the essential superparamagnetic behavior and a significantly prolonged stability on storage. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010