bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of STAT3 and its phosphorylated forms in mantle cell lymphoma cell lines and tumours
Authors: Lai Raymond , Rassidakis George Z , Medeiros L Jeffrey , Leventaki Vasiliki , Keating Micheal , Mcdonnell Timothy J 
Published: December 2002

AbstractThe pathogenesis of mantle cell lymphoma (MCL) is incompletely understood, although cyclin D1 overexpression leading to deregulated cell proliferation is probably important. Recent data suggest that interleukin (IL)‐10 can increase the proliferative activity of MCL cells. STAT3 (signal transducer and activator of transcription 3) is the signal transducer of IL‐10, and STAT3 is activated by phosphorylation. The hypothesis of this study is that STAT3 is activated in MCL. The expression of the two phosphorylated (i.e. active) forms of STAT3, pSTAT3‐tyr (phosphorylated at the tyrosine705 residue) and pSTAT3‐ser (phosphorylated at the serine727 residue), was assessed in four MCL cell lines and 12 MCL tumours using western blots and/or immunofluorescence staining techniques. All MCL cell lines expressed STAT3, but only one had detectable pSTAT3‐tyr and none had pSTAT3‐ser. Addition of IL‐10 rapidly resulted in expression of pSTAT3‐tyr but not pSTAT3‐ser. All eight cases of frozen MCL tumours examined had detectable pSTAT3‐tyr and pSTAT3‐ser. Immunofluorescence studies using four formalin‐fixed, paraffin wax‐embedded MCL tumours demonstrated cytoplasmic localization of STAT3, as opposed to the nuclear localization of the pSTAT3 species. In conclusion, these findings provide evidence that STAT3 is constitutively activated in MCL, supporting the concept that STAT3 signalling may be important in the pathogenesis of these tumours. Copyright © 2002 John Wiley & Sons, Ltd.
Differential expression of CCL19 by DC‐Lamp+ mature dendritic cells in human lymph node versus chronically inflamed skin
Authors: Katou Fuminori , Ohtani Haruo , Nakayama Takashi , Nagura Hiroshi , Yoshie Osamu , Motegi Katsutoshi 
Published: December 2002

AbstractDe novo formation of lymphoid tissue is one of the characteristic features of chronic inflammation. The formation of T cell–mature dendritic cell (DC) clusters has been previously demonstrated in chronically inflamed skin infected with Candida albicans. A functional similarity was also found between chronic inflammation and the T‐cell zone of lymph nodes (LNs), since a substantial fraction of phenotypically mature DCs in both tissues expressed CCL22 (macrophage‐derived chemokine; MDC) and were closely surrounded by memory‐type T cells expressing its receptor, CCR4. To analyse the nature of T cell–mature DC interactions further in chronically inflamed skin and LNs, the present study focuses on another chemokine system, namely CCL19 (EBI1 ligand chemokine; ELC), CCL21 (secondary lymphoid tissue chemokine; SLC) and their shared receptor, CCR7. RT‐PCR analysis revealed expression of CCL19, CCL21, and CCR7 at high levels in LNs and at low levels in inflamed skin. Using immunohistochemistry, the majority of DC‐Lamp+ mature DCs in the T‐cell area of LNs expressed CCL19 and were surrounded by CCR7+ naïve‐type lymphocytes, while CCL21 was expressed in reticular stromal cells and vascular endothelial cells. Very few mature DCs in LNs were found to express CCR7. In contrast, the majority of DC‐Lamp+ mature DCs in inflamed skin were totally negative for CCL19 and were surrounded by CCR7− memory‐type T cells. Furthermore, CCL21 expression in the inflamed skin was detected in dermal lymphatic endothelial cells and rare CCR7+ mature DCs were mostly seen within the lymphatic vessels. In normal skin, on the other hand, no cells immunoreactive for CCL19, CCL21, or CCR7 were found. The present study thus reveals a striking difference in the function of mature DCs between LNs and chronically inflamed skin. Copyright © 2002 John Wiley & Sons, Ltd.
Frequent genetic alterations in flat urothelial hyperplasias and concomitant papillary bladder cancer as detected by CGH, LOH, and FISH analyses
Authors: Obermann EC , Junker K , Stoehr R , Dietmaier W , Zaak D , Schubert J , Hofstaedter F , Knuechel R , Hartmann A 
Published: December 2002

AbstractFlat urothelial hyperplasia, defined as markedly thickened urothelium without cytological atypia, is regarded in the new WHO classification as a urothelial lesion without malignant potential. Frequent deletions of chromosome 9 detected by fluorescence in situ hybridization (FISH) have been previously reported in flat urothelial hyperplasias found in patients with papillary bladder cancer. Using comparative genomic hybridization (CGH) and microsatellite analysis, these hyperplasias and concomitant papillary tumours of the same patients were screened for other genetic alterations to validate and extend the previous findings. Eleven flat hyperplasias detected by 5‐ALA‐induced fluorescence endoscopy and ten papillary urothelial carcinomas (pTaG1–G2) from ten patients were investigated. After microdissection, the DNA of the lesions was pre‐amplified using whole genome amplification (I‐PEP‐PCR). Loss of heterozygosity (LOH) analyses were performed with five microsatellite markers at chromosomes 9p, 9q, and 17p. CGH was performed using standard protocols. In 6 of 11 hyperplasias and 7 of 10 papillary tumours, deletions at chromosome 9 were simultaneously shown by FISH, LOH, and CGH analyses. There was a good correlation between FISH, LOH, and CGH analyses, with identical results in 6 of 10 patients. In addition to deletions at chromosome 9, further genetic alterations were detected by CGH in 9 of 10 investigated hyperplasias, including changes frequently found in invasive papillary bladder cancer (loss of chromosomes 2q, 4, 8p, and 11p; gain of chromosome 17; and amplification at 11q12q13). There was considerable genetic heterogeneity between hyperplasias and papillary tumours, but a clonal relationship was suggested by LOH and/or CGH analyses in 5 of 10 cases. These data support the hypothesis that flat urothelial hyperplasias can display many genetic alterations commonly found in bladder cancer and could therefore be an early neoplastic lesion in the multistep development of invasive urothelial carcinoma. Copyright © 2002 John Wiley & Sons, Ltd.
Psoriatic lesional skin exhibits an aberrant expression pattern of interferon regulatory factor‐2 (IRF‐2)
Authors: van der Fits Leslie , van der Wel Leontine I , Laman Jon D , Prens Errol P , Verschuren Martie CM 
Published: December 2002

AbstractPsoriasis is a T‐cell‐mediated inflammatory skin disease. A Th1 cytokine profile with increased levels of interferon‐gamma (IFN‐γ) is predominant in skin and peripheral blood mononuclear cells (PBMCs) from psoriasis patients. Furthermore, psoriatic keratinocytes exhibit an aberrant sensitivity and response to IFN‐γ. The transcriptional activator interferon regulatory factor‐1 (IRF‐1) plays a crucial role in the activation of IFN‐γ‐induced gene expression. Recently it was shown that mice deficient in IRF‐2, a transcriptional repressor of IFN signalling and thereby acting as an IRF‐1 antagonist, display psoriasis‐like skin abnormalities. It was therefore hypothesized that a dysbalance between IRF‐1 and IRF‐2, the activator and repressor of IFN responses, respectively, contributes to the altered IFN‐γ signalling observed in patients with psoriasis. In the epidermis of patients with psoriasis and healthy controls, similar IRF‐1 and IRF‐2 mRNA expression levels were observed. Furthermore, it was not possible to detect any differences in IRF‐1 and IRF‐2 protein levels in nuclear extracts from the epidermis of controls and psoriasis patients by electrophoretic mobility shift assay and western blot analysis. Using double immunofluorescence labelling, it was observed that in normal skin IRF‐1 was expressed in keratinocytes throughout the epidermis, whereas IRF‐2 was restricted to the basal cell layer. In psoriatic skin, IRF‐1 expression was comparable to normal skin, whereas IRF‐2 was expressed in both basal and suprabasal cell layers. This altered IRF‐2 expression in suprabasal cell layers may therefore result in a dysbalance between the activator and repressor of IFN responses in these cell layers, putatively contributing to aberrant responses to IFN‐γ and eventually to the psoriatic skin phenotype. Copyright © 2002 John Wiley & Sons, Ltd.
Stages on the way to breast cancer
Authors: Going JJ 
Published: December 2002

AbstractPathways to breast cancer have been difficult to define using morphology alone. Although epithelial hyperplasia of usual type (HUT) is associated with moderately elevated breast cancer risk, molecular evidence placing it in a cancer precursor pathway is not clear‐cut. Recent evidence suggests that small numbers of cytokeratin 5/6 positive cells are precursors of separate lineages which acquire either cytokeratin 8/18/19 or smooth muscle actin (SMA) and cytokeratin 14 on separate pathways to fully differentiated epithelial and myoepithelial phenotypes (and may ultimately lose cytokeratin 5/6 expression). Immunohistochemistry shows that most HUT have a mixed precursor phenotype resembling normal breast with co‐expression of cytokeratin 5/6, 8/18/19 and SMA, in contrast to atypical ductal hyperplasia (ADH) and ductal carcinoma in situ which typically have a ‘mature’ luminal phenotype positive for cytokeratin 8/18/19 but lacking cytokeratin 5/6 expression. While this supports the idea of a biological discontinuity between HUT and ADH/DCIS, caution is called for in the diagnostic use of these reagents until greater experience has been accumulated, and other published data do show features of HUT intermediate between normal breast lobules and ADH. Copyright © 2002 John Wiley & Sons, Ltd.
NMR chemical shifts as probes for steric effects in mono‐ and disubstituted adamantanes
Authors: Seidl Peter Rudolf , Leal Kátia Zaccur , Yoneda Julliane Diniz 
Published: December 2002

AbstractSubstituent effects are widely used to investigate the factors affecting carbon‐13 chemical shifts. Adamantane and its derivatives are convenient probes for relative contributions to these factors owing to their symmetry and relative absence of ring strain. We have extended our studies on NMR chemical shifts of 1‐ and 2‐methyladamantanes to hydroxy, bromo, methoxy and acetamide substituents and also certain disubstituted (one of the groups being methyl) analogs. DFT/GIAO calculations at the B3LYP/6–31G(d,p) level show that, except for α‐effects, steric interactions are mainly responsible for substituent effects on chemical shifts. The CHARGE program is particularly well suited for localizing these effects and estimating their approximate shape and range.
Probing the solvation shell of organic molecules by intermolecular 1H NOESY
Authors: Bagno Alessandro 
Published: December 2002

AbstractThe solvation of some neutral and charged organic molecules (phenol, nitroanilines, tetraalkylammonium) in binary solvent mixtures was investigated by means of intermolecular 1H‐NOESY NMR spectroscopy. The solvation shell of the solute is, in most cases, selectively enriched in one of the cosolvents (preferential solvation). The origin of preferential solvation is discussed in terms of solute–solvent interactions and microheterogeneity in the solvent mixture. Copyright © 2002 John Wiley & Sons, Ltd.
Computational determination of the enthalpic and entropic contributions to the conformational preference of monosubstituted cyclohexanes. Molecular mechanics, semiempirical and density functional theory methods and ab initio calculations
Authors: Muñoz‐Muñiz Omar , Juaristi Eusebio 
Published: December 2002

AbstractSeveral computational methods [MM2, MM3, PM3, AM1, MNDO, HF/3‐21G(d), HF/6‐31G(d), B3LYP/3‐21G(d), B3LYP/6‐31G(d), MP2/6‐31G(d), etc.] were examined in their efficiency to reproduce the experimentally obtained thermodynamic data for axial ⇌ equatorial equilibria in benzylcyclohexane (7) and sulfur‐containing derivatives methylthio (8), methylsulfinyl (9), and methylsulfonylcyclohexane (10). While in general, best agreement between the theoretical results and the experimental data was found when electronic correlation was included in fairly robust MP2/6‐31G(d) calculations, for the estimation of conformational parameters in larger systems the use of lower level HF and B3LYP methods is anticipated to afford reliable data at reasonable computing times. In most cases, proper estimation of ΔS° parameters requires consideration of Δ

, which appears as dominant term for Δ

parameters. It is appreciated that a proper comprehension of the conformational behavior of monosubstituted cyclohexanes requires of satisfactory understanding of the enthalpic and entropic contributions to the conformational free energy difference, ΔG°. Copyright © 2002 John Wiley & Sons, Ltd.
Transition‐state geometry and activation energy calculation for the retro‐ene elimination reaction of propene from diallyl sulfide
Authors: Rodríguez Leonardo J. , Fermín José , Añez Rafael , Ocando‐Mavarez Edgar 
Published: December 2002

AbstractThe transition‐state geometry and the activation energy for the retro‐ene elimination of propene from diallyl sulfide were calculated at three levels of ab initio molecular orbital theory [HF, DFT(B3LYP) and MP2] combined with three basis sets (3–21G*, 6–31G* and 6–31 + G**). The activation energies were determined at room temperature and at 375 °C and compared with experimental data. Our calculations lead to transition states that consist of a non‐planar six‐center cyclic structure with a distorted chair‐like geometry. Moreover, the transition‐state geometry has a marked ‘product‐like’ character. We found that the B3LYP/6–31G* level produce activation values closer to the experimental values in a reasonable time. In all cases studied, the activation energies obtained from both the density functional and MP2 are better than those obtained using the Hartree–Fock method, which overestimates the barrier height. Regardless of the level of theory used [HF, DFT(B3LYP) or MP2], the basis sets 6–31G* and 6–31 + G** produce practically the same values of the activation energy; however, the first set is about twice as fast as the second. The transition‐state geometry obtained by different levels showed only slight structural differences. Copyright © 2002 John Wiley & Sons, Ltd.
Low‐temperature ionization of neutral hexacoordinate to ionic pentacoordinate silicon complexes. Unusual temperature, solvent and substituent effects
Authors: Kost Daniel , Kalikhman Inna , Kingston Vijeyakumar , Gostevskii Boris 
Published: December 2002

AbstractNeutral hexacoordinate complexes of silicon (1) ionize to pentacoordinate siliconium chloride salts (2) in CH2Cl2, CHCl3 or CHFCl2 solutions. 29Si NMR measurements prove that the extent of ionization increases as the temperature of the solution is lowered. The ionizations are slightly exothermic, and have negative entropies. It is shown that increased solvent polarity drives the reaction to the ionic side, i.e. that ion solvation is responsible for the ionization. The lack of a common‐ion effect on addition of tetrabutylammonium chloride indicates the formation of unseparated ion pairs. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and coordinating ability of chitosan dithiocarbamate and analogs towards Cu(II) ions
Authors: Humeres Eduardo , Pinheiro de Souza Eduardo , Debacher Nito Angelo , Aliev Abil E. 
Published: December 2002

AbstractPotassium chitosan dithiocarbamate (ChitDTC) was synthesized and characterized by elemental analysis and solid‐state 13C NMR spectroscopy. The degree of substitution (DS) (number of substituents per 100 2‐amino‐2‐deoxyglucopyranoside units) and molalities of the groups were calculated for acetylamino, amino and dithiocarbamate substituents in chitin, chitosan and ChitDTC. A comparative study of the retention and exchange of Cu(II) was performed with chitin, chitosan and ChitDTC at 30 °C, pH 6.0 (0.1 M succinate). The stability constants, KX, for the heterogenous equilibrium

were calculated assuming that complexing of Cu(II) ions was largely in a 1:1 ratio with respect to each group. The values of KX for each group were NHAc 45.1, DTC 3.14 × 103, and NH2 1.12 × 104. It is proposed that in the presence of succinate, the main species of aqua Cu(II) ion present in solution must be the uncharged Cu(II)–succinate complex that prevents the acetylamino, amino and DTC groups from forming complexes higher than 1:1. Also, this may explain the fact that the stability constant for DTC was lower than for the amino group. The method allows the characterization of the chelating ability of each group in ChitDTC with respect to metal ions. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of cyclodextrin on the hydrolysis of the pesticide fenitrothion [O,O‐dimethyl O‐(3‐methyl‐4‐nitrophenyl)phosphorothioate]
Authors: Vico Raquel V. , Buján Elba I. , de Rossi Rita H. 
Published: December 2002

AbstractThe hydrolysis of fenitrothion was studied at HO− concentrations between 0.099 and 0.999 M. The second‐order rate constant is 2.0 × 10−3 M
−1 s−1. The reaction is inhibited by β‐cyclodextrin at HO− concentrations of 0.5, 0.1 and 0.05 M. Saturation kinetics are observed in all cases. From the kinetic data, it is concluded that the main reaction pathway for the cyclodextrin‐mediated reaction is the reaction of HO− with the substrate complexed with the anion of β‐cyclodextrin. The rate constant for this reaction, k3, is about four times smaller than that for the reaction of the substrate with HO− in the solvent. The inhibition is attributed to the inclusion of the substrate with the phosphate group in an orientation that is difficult to reach by the ionized secondary OH groups of the cyclodextrin and protected for the attack of an external OH. Copyright © 2002 John Wiley & Sons, Ltd.
The generation of vinyl cations and excited triplet states by laser flash irradiation of arylalkynes
Authors: Kotani Masashi , Kobayashi Shinjiro , Chang Jeong‐Ah 
Published: December 2002

AbstractLaser flash photolysis of 4‐methoxyphenyl (anisyl) substituted alkynes 1 in protic and aprotic solvents was investigated in order to study the generation of the α‐anisylvinyl cations 2 by laser flash photoprotonation of the arylalkynes. Cations 2 were generated in 2,2,2‐trifluoroethanol, but the excited triplet state of arylalkyne 1 was detected in the aprotic solvents dichloromethane and acetonitrile. Reaction of the cations 2 with sodium azide was investigated and found to be diffusion controlled; reactions of 2 with cyclohexa‐1,3‐diene were also investigated and found to be appreciably affected by steric hindrance due to the β‐substituents. Copyright © 2002 John Wiley & Sons, Ltd.
Correlation of the rates of solvolysis of benzoyl chloride and derivatives using extended forms of the Grunwald–Winstein equation
Authors: Kevill Dennis N. , D'Souza Malcolm J. 
Published: December 2002

AbstractAvailable specific rates of solvolysis at 25 °C of benzoyl chloride and four para‐substituted derivatives for which both NT and YCl values are tabulated were analyzed using the extended (two‐term) Grunwald–Winstein equation. The ionization pathway with appreciable nucleophilic solvation of the incipient carbocation observed for the p‐methoxy derivative is accompanied by increasingly important regions of dominant operation of an addition–elimination pathway as the Hammett σ value for the substituent increases. Accordingly, for the p‐nitro derivative only the 97% HFIP data point deviates from the addition–elimination correlation. Correlations of the specific rates of solvolysis of 2,6‐dimethylbenzoyl chloride are improved by incorporation of a term governed by the aromatic ring parameter (I). Copyright © 2002 John Wiley & Sons, Ltd.
Reactions of trimethylstannide and trimethylsiliconide anions with aromatic and heteroaromatic substrates
Authors: Postigo Al , Vaillard Santiago E. , Rossi Roberto A. 
Published: December 2002

AbstractA parallel study was carried out on the reactions of Me3Sn− and Me3Si− ions towards aromatic and heteroaromatic substrates in hexamethylphosphoramide (HMPA) as solvent. It was found that Me3Si− ions are more reactive and therefore less selective than Me3Sn− ions. In HMPA, PhI and PhBr react with Me3Sn− ions through an HME pathway. PhCl also reacts by an HME reaction, but under photostimulation the SRN1 mechanism competes with the HME process. With PhF as substrate, Me3Sn− ions afford (4‐fluorophenyl)trimethylstannane, presumably through a hypervalent tin species. Under irradiation, the SRN1 mechanism operates concurrently with the formation of the hypervalent tin species. Me3Si− ions, on the other hand, react with PhX (X = Cl, Br, I) to yield the ipso substitution product, presumably through the intermediacy of a hypervalent silicon species. PhF affords, upon reaction with Me3Si− ions, o‐ and p‐fluorotrimethylsilylbenzenes together with the ipso substitution product PhSiMe3. A novel type of nucleophilic substitution mechanism takes place with Me3Si− ions upon reaction with aromatic and heteroaromatic substrates without classical leaving groups in HMPA. Copyright © 2002 John Wiley & Sons, Ltd.
How the by‐products hint at mechanisms and suggest new synthetic routes in some organolithium reactions
Authors: Nudelman Norma Sbarbati , García Graciela V. , Velurtas Susana 
Published: December 2002

AbstractThe recent proliferation of structural studies of organolithium reagents has led to an extended knowledge of the aggregation state of these pervasive synthetic intermediates. Nevertheless, detailed investigations of organolithium reaction mechanisms are still very limited. The most popular techniques in the relatively few reported studies are UV, EPR and NMR spectroscopy, the use of radical clocks and investigation of the stereochemical course of the reaction when applied. This paper describes how the search for minor products can be an additional mechanistic tool. Metal–halogen exchange was studied with a new suitable fast radical clock bearing a phenyl group at the alkene C‐terminus, even when the probe was able to trap very short‐lived radical intermediates, the results showed that the reaction proceeds through an open lithiated intermediate. In another study, radicals of benzil were generated on the lithium surface and their reactions studied in THF. Characterization of the minor products, the rates of decay of the reagent and formation of products, and also periodical EPR of the reaction mixture, allowed the proposal of the whole reaction mechanism. In both reactions studied, the detailed understanding of the reaction mechanisms based on the side‐products provided new more economical and environmentally friendly alternatives for the synthesis of substituted 2,3‐dihydrobenzo[b]furans and aromatic esters. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization and rheological properties of model alkali‐soluble rheology modifiers synthesized by reversible addition–fragmentation chain‐transfer polymerization
Authors: Sprong E. , De Wet‐Roos D. , Tonge M. P. , Sanderson R. D. 
Published: December 2002

AbstractModel alkali‐soluble rheology modifiers of different molar masses were synthesized by the reversible addition–fragmentation chain‐transfer polymerization of methyl methacrylate, methacrylic acid, and two different associative macromonomers. The polymerization kinetics showed good living character including well‐controlled molar mass, molar mass linearly increasing with conversion, and the ability to chain‐extend by forming an AB block copolymer. The steady‐shear and dynamic properties of a core‐shell emulsion, thickened with the different model alkali‐soluble rheology modifiers, were measured at constant pH and temperature. The steady‐shear data for latex solutions with conventional rheology modifiers exhibited the expected thickening, whereas the associative rheology modifiers showed contrasting rheology behavior. The dynamic measurements revealed that the latex solutions thickened with the conventional rheology modifiers exhibit solid‐like (dominant G′) behavior as compared with the associative rheology modifiers that give the latex solution a liquid‐like (dominant G″) character. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 223–235, 2003