bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structurally Characterized Hetero‐Oligopolyphenylenes: Synthetic Advances Toward Next‐Generation Heterosuperbenzenes
Authors: Gregg Daniel J. , Ollagnier Cecile M. A. , Fitchett Christopher M. , Draper Sylvia M. 
Published: January 2006

AbstractThe successful Diels–Alder [2+4] cycloaddition1 of dipyrimidyl acetylene and suitably substituted 2,3,4,5‐tetraarylcyclopenta‐2,4‐dien‐1‐ones (3–7) generates a series of selectively functionalized hexaarylbenzenes. Each has two pairs of peripheral functional groups (R′ and R=tert‐butyl 8 and R=methyl 9, methoxy 10, bromo 11, triisopropylsilylethynyl 12) and four ortho‐imine nitrogen atoms. The dibromo derivative 11 is a useful precursor for the formation of a mono ethynyl 13 and diethynyl 14 substituted polyphenylene. Changing the dienophile to di(2‐thienyl)acetylene gives an S‐heteroatom polyphenylene 15. The compounds were fully characterized by using 1H, 13C and a range of 2 D NMR spectroscopic techniques, elemental analysis, and mass spectrometry. Oxidative cyclodehydrogenation of dimethoxy hexaphenylbenzene 10 by using iron(III) chloride results in the formation of a spirocyclic dienone 16, which in a separate reaction undergoes dienone/phenol rearrangement to give the first 4‐fused‐ring, N‐heterosuperbenzene (HSB) 17. Six single crystal molecular structures reveal the commonality of unidirectional twisting of the external aromatic rings in these heteroatom polyphenylenes. The twist angles and any H‐bonding or interdigitation in these structures are discussed.
Inhibition of human telomerase reverse transcriptase by nonsteroidal antiinflammatory drugs in colon carcinoma
Authors: He Hua , Xia Harry Hua‐Xiang , Wang Ji De , Gu Qing , Lin Marie C.M. , Zou Bing , Lam Shiu Kum , Chan Annie O.O. , Yuen Man Fung , Kung Hsiang Fu , Wong Benjamin Chun‐Yu 
Published: January 2006

AbstractBACKGROUNDTelomerase activation, which is observed in most human cancers, plays an important role in carcinogenesis. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activity. The aim of the study was to investigate whether nonsteroidal antiinflammatory drugs (NSAIDs) inhibit telomerase activity and hTERT.METHODSFour colon carcinoma cell lines, HT‐29, COLO205, CRL‐2134, and SW1116, were used in the experiments. Polymerase chain reaction‐based telomeric repeat amplification (TRAP) enzyme‐linked immunosorbent assay (ELISA) was used to measure telomerase activity in the cells after treatment with aspirin, indomethacin, or SC‐236 (a specific cyclooxygenase‐2 [COX‐2] inhibitor). Expression of hTERT mRNA and protein was detected by reverse transcription–polymerase chain reaction (RT‐PCR) and Western blotting, respectively. The dual luciferase reporter assay was performed to identify the potential cis‐response elements to NSAIDs in the promoter region of hTERT.RESULTSAspirin, indomethacin, and SC‐236 inhibited telomerase activity in HT‐29, COLO205, and CRL‐2134 cell lines, but not in the SW1116 cell line. NSAIDs inhibited hTERT mRNA and protein expression through suppression of hTERT transcriptional activity. The hTERT promoter fragment −145 to −330 basepairs (bp) upstream of the ATG starting site was sufficient to respond to the NSAID‐induced inhibitory effect and the inhibition was COX‐2‐independent.CONCLUSIONNSAIDs inhibit telomerase activity at hTERT transcriptional, mRNA, and protein levels in colon carcinoma cells. The hTERT promoter fragment −145 to −330 bp may be the cis‐response element to NSAIDs. Cancer 2006. © 2006 American Cancer Society.
His239Arg SNP of HRAD9 is associated with lung adenocarcinoma
Authors: Maniwa Yoshimasa , Yoshimura Masahiro , Bermudez Vladimir P. , Okada Kenji , Kanomata Naoki , Ohbayashi Chiho , Nishimura Yoshihiro , Hayashi Yoshitake , Hurwitz Jerard , Okita Yutaka 
Published: January 2006

AbstractBACKGROUNDIt was previously reported that a functional human (h) Rad9 protein accumulated in the nuclei of nonsmall cell lung carcinoma (NSCLC) cells. Those experiments, however, did not examine whether the hRad9 gene was mutated in those cells. The sequence of the HRAD9 gene in NSCLC cells was investigated.METHODSThe sequence of the HRAD9 was examined in tumor and peripheral normal lung tissues obtained from 50 lung adenocarcinoma patients during surgery. The expression of its mRNA using reverse transcription polymerase chain reaction (RT‐PCR) was also examined.RESULTSNo sequence alterations were detected in the HRAD9 gene, which was found to be normally transcribed in surgically resected lung carcinoma cells. However, in eight (16.0%) cases a single nucleotide polymorphism (SNP) was observed at the second position of codon 239 (His/Arg heterozygous variant) of the gene. This frequency was significantly higher than that found in the normal population.CONCLUSIONSWhereas the capacity to produce a functional hRad9 protein was intact in lung adenocarcinoma cells, a nonsynonymous SNP of HRAD9 was detected that might be associated with the development of lung adenocarcinoma. Cancer 2006. © 2006 American Cancer Society.
Valproate enhances imatinib‐induced growth arrest and apoptosis in chronic myeloid leukemia cells
Authors: Morotti Alessandro , Cilloni Daniela , Messa Francesca , Arruga Francesca , Defilippi Ilaria , Carturan Sonia , Catalano Renata , Rosso Valentina , Chiarenza Annalisa , Pilatrino Chiara , Guerrasio Angelo , Taulli Riccardo , Bracco Enrico , Pautasso Marisa , Baraban Daniela , Gottardi Enrico , Saglio Giuseppe 
Published: January 2006

AbstractBACKGROUNDThe objective of this study was to evaluate the ability of the clinically available histone deacetylase (HDAC) inhibitor valproate to enhance the cytotoxicity of the Bcr‐Abl inhibitor imatinib in imatinib‐resistant cell lines.METHODSInteractions between imatinib, and valproate have been examined in imatinib‐sensitive and ‐resistant chronic myeloid leukemia (CML)cell lines (K562, KCL‐22, CML‐T1) and in bone marrow mononuclear cells (MNCs) derived from imatinib‐resistant CML patients.RESULTSIn imatinib‐sensitive cell lines, cotreatment with imatinib 0.5 μM and valproate 5 μM for 48 hours potently enhanced imatinib‐induced growth arrest and apoptosis. In resistant cell lines and in primary MNCs derived from imatinib‐resistant patients, valproate restored sensitivity to the cytotoxic effects of imatinib. Coexposure of cells to valproate and imatinib was associated with repression of several genes involved in Bcr‐Abl transformation. In particular, the combination valproate–imatinib downregulated the expression of Bcr‐Abl and the antiapoptotic protein Bcl‐2, which is particularly overexpressed in imatinib‐resistant clones.CONCLUSIONSData from this study suggested that administration of the clinically available HDAC inhibitor valproate may be a powerful strategy to enhance cytotoxic effects of imatinib in those patient resistant to imatinib or in which complete cytogenetic remission has been not reached. Cancer 2006. © 2006 American Cancer Society.
Comparative analysis of mRNA and protein expression of Popdc1 (Bves) during early development in the chick embryo†
Authors: Torlopp Angela , Breher Stephanie S. , Schlüter Jan , Brand Thomas 
Published: January 2006

AbstractThe isolation of the Popeye gene family was based on its preferential expression in striated muscle tissue. Recently, a monoclonal antibody against chick Popdc1 (also known as Bves) became available and was used in this study to comparatively analyze the expression pattern of Popdc1 at both the protein and mRNA level during early chick embryogenesis. Using whole‐mount immunohistochemistry, expression in the heart was first observed at Hamburger and Hamilton (HH) stage 10 in the presumptive left ventricular segment. Cardiac expression was confined to differentiated cardiac myocytes, and undifferentiated myocytes at the anterior and posterior pole showed little expression. After looping, the outer curvature myocardium showed prominent Popdc1 staining, whereas the inner curvature was unlabeled. Despite previous reports, Popdc1 protein was not detectable at any time point in the proepicardium, epicardium, or the smooth muscle layer of the coronary vessels. Whole‐mount in situ hybridization using a full‐length Popdc1 probe detected novel expression domains, which have not been described previously. Popdc1 mRNA was found in Hensen's node at HH stage 4, and by HH stage 5+, expression became asymmetric. In addition, Popdc1 mRNA was found in pharyngeal endoderm and in the notochordal plate. Subsequently, beginning at HH stage 9, Popdc1 mRNA expression was found in the cardiac mesoderm and expression was maintained in the heart in a pattern very similar to the one observed by antibody staining. Developmental Dynamics 235:691–700, 2006. © 2006 Wiley‐Liss, Inc.
Bves, a member of the Popeye domain‐containing gene family
Authors: Osler Megan E. , Smith Travis K. , Bader David M. 
Published: January 2006

AbstractBves was discovered through subtractive screens designed to identify heart‐enriched transcripts. Bves is a transmembrane protein that possesses a highly conserved structure among species of the animal kingdom. Various approaches have been used to elucidate the expression pattern of Bves mRNA and protein as well as its function in developing and mature organisms. Emerging evidence indicates that this protein is present in muscle and epithelia of developing embryos and the adult. In vitro functional studies predict a role in cell–cell interaction and/or adhesion. In vivo analysis of protein function is very limited at present, but recent work in Xenopus supports the importance of Bves in epithelial integrity. Presented in this review is a compilation of published findings concerning Bves gene and protein characteristics, expression patterns in embryos and cells, and functional significance as determined thus far. Presently, the literature supports a hypothesis that Bves is essential to the junctional architecture of muscle and epithelial cell types. Although there remain aspects of Bves structure, expression, and function that are not completely resolved, now is an appropriate time to summarize current knowledge about this protein, the remaining questions, and what its potential role in development might be. This review will serve as a departure point for others who become interested in the study of this highly conserved protein. Developmental Dynamics 235:586–593, 2006. © 2006 Wiley‐Liss, Inc.
Experimental hypoxia and embryonic angiogenesis†
Authors: Naňka O. , Valášek P. , Dvořáková M. , Grim M. 
Published: January 2006

AbstractWe examined the role of hypoxia and HIF factors in embryonic angiogenesis and correlated the degree of hypoxia with the level of HIF and VEGF expression and blood vessel formation. Quail eggs were incubated in normoxic and hypoxic (16% O2) conditions. Tissue hypoxia marker, pimonidazol hydrochloride, was applied in vivo for 1 hr and detected in sections with Hypoxyprobe‐1 Ab. VEGF and HIF expression was detected by in situ hybridization. HIF‐1α protein was detected in sections and by Western blot. Endothelial cells were visualized with QH‐1 antibody. Hypoxic regions were detected even in normoxic control embryos, mainly in brain, neural tube, branchial arches, limb primordia, and mesonephros. The expression patterns of HIF‐1α and HIF‐1β factors followed, in general, the Hypoxyprobe‐1 marked regions. HIF‐2α was predominantly expressed in endothelial cells. Diffuse VEGF expression was detected in hypoxic areas of neural tube, myocardium, digestive tube, and most prominently in mesonephros. Growing capillaries were directed to areas of VEGF positivity. Hypoxic regions in hypoxic embryos were larger and stained more intensely. VEGF and HIF‐1 factors were proportionately elevated in Hypoxyprobe‐1 marked regions without being expressed at new sites and were followed by increased angiogenesis. Our results demonstrate that normal embryonic vascular development involves the HIF‐VEGF regulatory cascade. Experimentally increasing the level of hypoxia to a moderate level resulted in over‐expression of HIF‐1 factors and VEGF followed by an increase in the density of developing vessels. These data indicate that embryonic angiogenesis is responsive to environmental oxygen tension and, therefore, is not entirely genetically controlled. Developmental Dynamics 235:723–733, 2006. © 2006 Wiley‐Liss, Inc.
Iodine Attack on the Metalloligand [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)]: Surprising Formation of the [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)]+ Cation
Authors: García‐Castro María , Martín Avelino , Mena Miguel , Poblet Josep‐M. , Yélamos Carlos 
Published: January 2006

AbstractThe reactivity of the trinuclear imido‐nitrido complex [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)] (1) and derivatives thereof withiodine has been investigated. Treatment of the indium(I)adduct [IIn{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}] (2) with I2 (1 equiv.) in benzene afforded the indium(III) complex [I3In{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}] (3), but with excess of iodine the precipitation of orange crystals of the ionic complex [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)][InI4] (4) takes place. Analogous treatment of the metalloligand 1 with I2 in toluene gave initially the iodine(I) derivative [I{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}][I3] (5). Surprisingly, toluene solutions of 5 at room temperature produced crystals of the ionic complex [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)][I3]·C7H8 (6·C7H8). The trinuclear titanium cation [Ti3(η5‐C5Me5)3I2(μ‐NH)3(NH3)]+ of complexes 4 and 6 has been structurally characterized by a combination of X‐ray and DFT studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Complexes of Bidentate Phosphane Selenide Ligands with Mesitylenetellurenyl Iodide and with Tellurium Diiodide
Authors: Hrib Cristian G. , Jones Peter G. , du Mont Wolf‐W. , Lippolis Vito , Devillanova Francesco A. 
Published: January 2006

AbstractBis(diphenylphosphanyl)methane diselenide (dppmSe2, 1) and bis(diphenylphosphanyl)ethane diselenide (dppeSe2, 2) reacted with 2 equiv. Br2 or I2 to form the insoluble solid products, dppm(SeX2)2 (X = Br, 3; X = I, 4) and dppe(SeX2)2 (X = Br, 5; X = I, 6). However, using the iodine‐like electrophile mesitylenetellurenyl iodide (MesTeI, 7), fairly soluble complexes, dppmSe2[Te(I)Mes]2 (8) and dppeSe2[Te(I)Mes]2 (9), were obtained. Complexes 8 and 9 contain two T‐shaped (10‐Te‐3) Se–Te(Mes)–I moieties bridged by dppm or dppe; solid 9 exhibits intermolecular soft–soft interactions between approximately linear Se–Te–I units. In a side reaction accompanying the crystallisation of complex 8, or by the reaction of 1 with Te and I2, a chelate complex dppmSe2TeI2 (10) was formed. Fortuitously, a crystal of the related compound dppeSe2TeI2 (11) was also obtained. In 10, a square planar cis‐Se2TeI2 group is part of a six‐membered ring, and 11 is a coordination polymer with trans‐Se2TeI2 moieties bridged by dppe. Averaged 31P‐ and 77Se NMR signals including 77Se–31P couplings, together with broad 125Te NMR singlets indicate phosphane selenide ligand exchange in solution, that is, the kinetically labile behaviour of complexes 8 and 9. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
TheAlpher, Bethe, Gamowof isoelectric focusing, the alpha‐Centaury of electrokinetic methodologies. Part I
Authors: Righetti Pier Giorgio 
Published: January 2006

AbstractThe birth and evolution of IEF in conventional carrier ampholyte buffers is reviewed here, from a shaky start during World War II,viadesperate attempts of Svensson to create pH gradients by stationary electrolysis of salts, to the development of the IEF theory and the solution of the steady‐state equation. The remarkable synthetic process of Ampholines, as ingeniously devised by Vesterberg, is additionally recalled, with a thorough description of the fundamental properties of these amphoteric buffers, creating and maintaining the pH gradient under strong electric fields. The review ends with a mention of the major contributions of B. J. Radola to this field, namely analytical and preparative IEF in granulated Sephadex layers and the development of ultrathin IEF, in polyacrylamide gels as thin as 20–100 μm. The latter technique paved the way to DNA sequencing gels and to CZE. The symptoms of decay are here presented through the simulations of Mosher and Thormann, clearly indicating an isotachophoretic mechanism for pH gradient decay with time. The decay of IEF was the birth of IPGs.
Curved DNA molecules migrate anomalously slowly in polyacrylamide gels even at zero gel concentration
Authors: Stellwagen Nancy C. 
Published: January 2006

AbstractThe electrophoretic mobilities of curved and normal DNA molecules of the same size have been measured in polyacrylamide gels containing various acrylamide concentrations and cross‐linker ratios. Ferguson plots were constructed to extrapolate the observed mobilities to zero gel concentration. The DNA samples were two 147‐bp restriction fragments, called 12A and 12B, obtained from the MspI digestion of plasmid pBR322, and head‐to‐tail multimers of each fragment. Fragment 12A is stably curved and migrates anomalously slowly in polyacrylamide gels; fragment 12B has the conformation of normal DNA and migrates with normal electrophoretic mobilities. The extrapolated mobilities of the curved fragment 12A and its multimers at zero gel concentration are lower than the extrapolated mobilities of the normal fragment 12B and its multimers. The free solution mobility of the curved fragment 12A, measured by CE, is also lower than that of the normal fragment 12B. The combined results indicate that the extrapolated mobilities observed for curved DNA molecules at zero polyacrylamide gel concentration reflect the intrinsic differences in their free solution mobilities.
Comparison of the use of anionic and cationic surfactants for the separation of steroids based on MEKC and sweeping‐MEKC modes
Authors: Shen Hui‐Ju , Lin Cheng‐Huang 
Published: January 2006

AbstractIn attempts to improve the selectivity and sensitivity of steroid separation and to determine their migration order, a comparison of the use of anionic and cationic surfactants based on the MEKC and sweeping‐MEKC modes was made. A mixture of six steroids (progesterone, 17‐hydroxy progesterone, 11‐deoxycortisol, corticosterone, cortisone, and cortisol) could be separated and detected by means of the CE/UV‐absorption method. The order of migration time for these steroids was compared under various conditions, including acidic/alkaline buffers, anionic/cationic surfactants, and positive/negative applied voltage, causing the direction of the EOF and the migration of micelles to change. The major rules for generally predicting the migration order of steroids are summarized. The detection limits were significantly improved when the sweeping‐MEKC mode was applied.
Determination of antidepressants in surface and waste water samples by capillary electrophoresis with electrospray ionization mass spectrometric detection after preconcentration using off‐line solid‐phase extraction
Authors: Himmelsbach Markus , Buchberger Wolfgang , Klampfl Christian W. 
Published: January 2006

AbstractA method for the quantitative determination of seven major antidepressants in surface waters and sewage treatment plant effluents by CE using ESI‐MS is presented. Calibration curves for the selected analytes were prepared in Milli‐Q purified water and Danube river water extract covering a concentration range of at least one order of magnitude. LODs achieved were between 6 and 13 μg/L for Trazodone and 39 and 53 μg/L for Sertraline in the Milli‐Q purified water and Danube river water matrix, respectively. For sample preparation eight different SPE materials were investigated. Best results were obtained for a resin based on hydrophilic divinylbenzene (recoveries from Milli‐Q purified water 93–96%; from Danube river water 85–99%). Finally, a series of eight sewage treatment plant effluents were investigated with respect to their content in the selected antidepressants. Six of these samples were tested positive for antidepressants, in particular Venlafaxine, Citalopram and Trazodone in concentrations between 36 and 322 ng/L.
Fluorescence imaging of sample zone narrowing and dispersion in a glass microchip: The effects of organic solvent (acetonitrile)–salt mixtures in the sample matrix and surfactant micelles in the running buffer
Authors: Jia Zhijian , Lee Yi‐kuen , Fang Qun , Huie Carmen W. 
Published: January 2006

AbstractA mismatch in the EOF velocities between the sample zone and running buffer region is known to generate pressure‐driven, parabolic flow profile of the sample plug in electrokinetic separation systems. In the present study, video fluorescence microscopy was employed to capture real‐time dynamics of the sample plug (containing fluorescein as the probe molecule) in a discontinuous conductivity system within a glass microchip, in which the sample matrix consisted of a mixture of ACN and salt (NaCl), and the running buffer contained sodium cholate (SC) micelles as the pseudo‐stationary phase (i.e., performing “ACN stacking” in the mode of MEKC). Upon application of the separation voltage, the video images revealed that zone narrowing and broadening of the probe molecules occurred as the sample plug headed toward the cathode during the initial time period, probably resulting in part from the stacking/sweeping, and destacking of the SC micelles at the boundaries between the sample zone and running buffer. Interestingly, a second sample zone narrowing event can be observed as the sample plug moved further toward the cathode, which could be attributed to the sweeping of the slower moving probe molecules by the faster moving SC micelles that originated from the anode. This phenomenon was studied as a function of pH, sample plug length, as well as the concentration of organic solvent and salt in the sample matrix. The data suggested that the presence of large amounts of an organic solvent (such as ACN or methanol) and salts in the sample matrix not only induces sample dispersion due to the formation of a pressure‐driven (hydrodynamic) flow, but may also lead to the formation of a double sample zone narrowing phenomenon by altering the local EOF dynamics within the separation system.
Capillary electrophoretic chiral separation of hydroxychloroquine and its metabolites in the microsomal fraction of liver homogenates
Authors: Dickow Cardoso Carmem , Polisel Jabor Valquíria A. , Sueli Bonato Pierina 
Published: January 2006

AbstractA rapid, selective, and low‐cost chiral capillary electrophoretic method was developed for the simultaneous analysis of hydroxychloroquine (HCQ) and its three chiral metabolites: desethylchloroquine (DCQ), desethylhydroxychloroquine (DHCQ), and bisdesethylchloroquine (BDCQ) in the microsomal fraction of liver homogenates. After liquid–liquid extraction using toluene as extracting solvent, the drug and metabolites were resolved on a fused‐silica capillary (50 μm ID, 50 cm total length, and 42 cm effective length), using 100 mmol/L of Tris/phosphate buffer, pH 9.0 containing 1% w/v sulfated‐β‐CD and 30 mg/mL hydroxypropyl‐β‐CD. Detection was carried out at 220 nm. The extraction procedure was efficient in removing endogenous interferents, and low values (≤15%) for CVs and deviation from theoretical values were demonstrated for both within‐day and between‐day assays. The quantitation limit was 125 ng/mL with linear response over the 125–2000 ng/mL of concentration range for all metabolites. After validation, the method was used for an in vitro metabolism study of HCQ. The major HCQ metabolite formed by microsomal enzymes was (−)‐(R)‐DHCQ.