bluuebunny/crossref_metadata_2025_split huggingface dataset:
Weak agonist self‐peptides promote selection and tuning of virus‐specific T cells
Authors: Saibil Samuel D. , Ohteki Toshiaki , White Forest M. , Luscher Mark , Zakarian Arsen , Elford Alisha , Shabanowitz Jeffery , Nishina Hiroshi , Hugo Patrice , Penninger Josef , Barber Brian , Hunt Donald F. , Ohashi Pamela S. 
Published: March 2003

AbstractRecent progress has begun to define the interactions and signaling pathways that are triggered during positive selection. To identify and further examine self‐peptides that can mediate positive selection, we searched a protein‐database to find peptides that have minimal homology with the viral peptide (p33) that activates a defined P14 transgenic TCR. We identified four peptides that could bind the restriction element H‐2Db and induce proliferation of P14 transgenic splenocytes at high concentration. Two of the four peptides (DBM and RPP) were able to positively select thevirus‐specific TCR in fetal thymic organ culture but were unable to induce clonal deletion. Reverse‐phase HPLC and mass spectrometry demonstrated that these peptides were presented by H‐2Db molecules on thymic epithelial cell lines. We also examined whether the selecting ligands altered T cell responsiveness in vitro. DBM‐selected T cells lost their ability to respond to the positively selecting ligand DBM, whereas RPP‐selected T cells only retainrd their ability to respond to high concentrations of RPP. These results demonstrate that self‐peptides that mediate positiveselection can differentially "tune" the activation threshold of T cells and alter the functional repertoire of T cells.
Toll‐like receptor‐mediated tyrosine phosphorylation of paxillin via MyD88‐dependent and ‐independent pathways
Authors: Hazeki Kaoru , Masuda Naoyo , Funami Kenji , Sukenobu Naoe , Matsumoto Misako , Akira Shizuo , Takeda Kiyoshi , Seya Tsukasa , Hazeki Osamu 
Published: March 2003

AbstractToll‐like receptor (TLR)‐mediated recognition of pathogens represents one of the most important mechanisms of innate immunity. A proximal signaling event of TLR is the direct binding of an adaptor protein MyD88 to TLR and recruitment of the IL‐1R‐associated kinase (IRAK). In the present study, we examined the effect of several TLR ligands on protein tyrosine phosphorylation in rat macrophages. Macrophage‐activating lipopeptide‐2 kDa (MALP2) and lipoarabinomannan were used as activators of TLR2, while lipopolysaccharides (LPS) and lipoteichoic acid were used as TLR4 ligands. All these ligands induced tyrosine phosphorylation of proline‐rich tyrosine kinase 2 (Pyk2) and its substrate paxillin, an integrin‐associated focal adhesion adaptor protein, in the macrophages. PP2, an inhibitor of Src family tyrosine kinases, prevented the TLR‐induced phosphorylation of paxillin and Pyk2 without affecting TLR‐induced IRAK activation. MALP2 failed to induce paxillin phosphorylation in the macrophages from MyD88‐knockout mice. In contrast, the effect of LPS weakened, but was still observed even in the MyD88‐deficient cells. Thus, TLR regulate the function of paxillin in an Src family‐dependent mechanism through both MyD88‐dependent and MyD88‐independent pathways.
Superoxide activates very late antigen‐4 on an eosinophil cell line and increases cellular binding to vascular cell adhesion molecule‐1
Authors: Chuang Kuo‐Pin , Tsai Wei‐Shi , Wang Ying‐Jan , Shieh Chi‐Chang 
Published: March 2003

AbstractThe recruitment of eosinophils to the airway is a key event in the pathogenesis of allergy. Very late antigen‐4 (VLA‐4), an integrin ligand for vascular cell adhesion molecule‐1 (VCAM‐1), is expressed on eosinophils. VLA‐4‐mediated adhesion of eosinophils to VCAM‐1 may contribute to their selective recruitment to tissues in allergy. Reactive oxygen species (ROS), including nitric oxide (NO), are abundant in the airway of allergic patients, but their role in pathogenesis of allergy is unclear. In this investigation, we studied the effects of ROS on integrin‐mediated eosinophil adhesion. Recombinant soluble VCAM‐1 and ICAM‐1 were used to test the effects of ROS on the integrin‐mediated adhesion of an eosinophil cell line. We used phorbol 12‐myristate 13‐acetate‐stimulated neutrophils and hypoxanthine to generate superoxide, NO donors as sources of NO, and a static cell‐to‐protein adhesion assay to analyze cellular adhesion. Stimulated neutrophils significantly increased eosinophil binding to VCAM‐1, which was reversed in the presence of superoxide dismutase. Neutrophils from a chronic granulomatous disease patient lacked this activity in enhancing eosinophil adhesion. Our results suggest that the balance between ROS molecules in different tissue microenvironments may change the integrin‐mediated leukocyte adhesion and is likely to be a key factor in leukocyte recruitment in allergic inflammation.
Characterization of antigen‐specific repertoire diversity following in vitro restimulation by a recombinant adenovirus expressing human cytomegalovirus pp65
Authors: Hamel Yamina , Rohrlich Pierre , Baron Véronique , Bonhomme Delphine , Rieux‐Laucat Frederic , Necker Antje , Lemonnier François , Ferradini Laurent , Fischer Alain , Cavazzana‐Calvo Marina 
Published: March 2003

AbstractHuman cytomegalovirus (HCMV) and adenovirus cause significant morbidity and mortality in immunocompromised hosts undergoing allogeneic stem cell transplantation. We have previously establisheda procedure for the generation of polyclonal CTL with specificity against adenovirus and HCMV using a recombinant adenovirus encoding the HCMV pp65 protein (RAdpp65). However, specific CTL expandedafter in vitro culture steps were subjected to several in vitro restimulations and, depending on the protocol adopted, this could lead to a selection bias, compromising the clinical benefit. To determine which part of the memory repertoire is selected after in vitro restimulation, we have followed the specificity and clonal composition of pp65‐peptide‐specific CD8+ T cells in HLA‐A*201 individuals before and after repeated in vitro restimulation of cells with RAdpp65, combining HLA tetrameric complexes and immunoscope analysis. Tetramer staining showed that, after in vitro restimulation, up to 60% of CD8+ T cells were virus‐specific. Immunoscope analysis showed that the predominant TCRBV diversity of pp65‐specific clones was conserved, demonstrating that the memory repertoire was preserved all along the procedure. Altogether, these results suggest that the use of RAdpp65 to induce CMV‐ and adenovirus‐specific CTL maybe appropriate for immunotherapy.
Design and Structural Analysis of Metallamacrocycles Based on Zinc Halides and a V‐Shaped Bismonodentate Ligand of the Cyclophane Type
Authors: Klein Cédric , Graf Ernest , Hosseini Mir Wais , De Cian André , Kyritsakas Nathalie 
Published: March 2003

AbstractThe ligand 1, based on the [1,1,1,1]cyclophane skeleton and bearing two pyridine units as monodentate coordination sites on the same face of the backbone, leads, in the presence of ZnX2 (X = Cl, Br or I) complexes, to three isostructural neutral metallamacrocycles with an M/L ratio of 2:2. All three binuclear complexes have been characterised in the solid state by single‐crystal X‐ray diffraction. All three metallamacrocycles possess a roof‐shaped geometry affording a pocket with a single opening. The latter is occupied by solvent molecules in the solid state. A correlation between the size of the halide and dimensions of the pocket is described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Bis‐Aminals of Linear Tetraamines: Kinetic and Thermodynamic Aspects of the Condensation Reaction
Authors: Chuburu Françoise , Tripier Raphaël , Baccon Michel Le , Handel Henri 
Published: March 2003

AbstractThe kinetic and thermodynamic aspects of the condensation reaction of dicarbonyl compounds with linear tetraamines were examined in the light of identification of intermediates and DFT calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Xe@cryptophane Complexes with C2 Symmetry: Synthesis and Investigations by 129Xe NMR of the Consequences of the Size of the Host Cavity for Xenon Encapsulation
Authors: Brotin Thierry , Dutasta Jean‐Pierre 
Published: March 2003

AbstractNew cryptophanes‐223 (1), ‐233 (2), and ‐224 (3) with C2 symmetry, bearing different linkers connecting the two cyclotriveratrylene units were synthesized following a multi‐step procedure. The formation of the xenon@cryptophane complexes was investigated by 129Xe NMR spectroscopy. Cryptophanes‐223 (1) and ‐233 (2) complex xenon efficiently in 1,1,2,2‐[D2]tetrachloroethane solution with somewhat lower binding constants (K = 2810 M−1 and 810 M−1 respectively at 278 K) than that observed with cryptophane‐A (K = 3900 M−1). The free and bound guests were observed at room temperature under slow‐exchange conditions on the 129Xe NMR timescale. A linear relationship was observed between the binding constants and the internal volume of the hosts. Under the same conditions, the Xe@cryptophane‐224 [Xe3] complex underwent a fast‐exchange process on the NMR timescale. The decomplexation activation energies Ea, and the associated parameters ΔH‡ and ΔS‡, were determined for the Xe1 and Xe2 complexes from variable temperature 1D‐EXSY experiments. These investigations emphasized the importance of the size of the internal cavity of the cryptophanes for guest encapsulation, and the extreme sensitivity of the 129Xe chemical shift toward slight structural modifications of the atom’s environment. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Polysubstituted Alkenes by Heck Vinylation or Suzuki Cross‐Coupling Reactions in the Presence of a Tetraphosphane−Palladium Catalyst
Authors: Berthiol Florian , Doucet Henri , Santelli Maurice 
Published: March 2003

AbstractThrough the use of [PdCl(C3H5)]2/cis,cis,cis‐1,2,3,4‐tetrakis[(diphenylphosphanyl)methyl]cyclopentane as a catalyst, a range of vinyl bromides undergo Suzuki cross‐couplings with arylboronic acids in good yields. Furthermore, the catalyst can be used at low loadings, even for reactions of sterically hindered substrates. Mediated by this catalyst, stilbene and 1,1‐diphenylethylene undergo Heck reactions with aryl halides to give triarylethylene derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Ingroup identification as a moderator of positive–negative asymmetry in social discrimination
Authors: Hodson Gordon , Dovidio John F. , Esses Victoria M. 
Published: March 2003

AbstractGroup members typically favour ingroups over outgroups, particularly when distributing positive rather than negative resources. The present investigation examined whether the positive–negative discrimination asymmetry in the minimal group paradigm varies as a function of ingroup identification. After being categorized into arbitrary groups, participants expressing low to high ingroup identification allocated positive, neutral, or negative outcomes on the basis of group membership (i.e. ingroup versus outgroup recipients). The interaction between ingroup identification and outcome valence revealed that identification influenced the magnitude of discrimination asymmetry. Specifically, increases in identification led to discrimination in favour of the ingroup for positive but not negative outcomes. The implications for intergroup behaviour more generally are considered. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of pharmaceutical drugs by a modified nonaqueous capillary electrophoresis – mass spectrometry method
Authors: Peri‐Okonny Unita L. , Kenndler Ernst , Stubbs R. John , Guzman Norberto A. 
Published: March 2003

AbstractA simple method for the separation and characterization of a group of nine basic compounds, comprising seven tricyclic antidepressant and two bronchodilator drugs, by nonaqueous capillary electrophoresis (NACE) employing ultraviolet and mass spectrometry detection is described. After optimization of the electrophoresis separation conditions, including the compositions of the electrolyte and the organic solvent, a reliable separation of all nine basic analytes was achieved in 80 mM ammonium formate dissolved in a methanol‐acetonitrite (80:20 v/v) mixture, having an apparent pH of 8.7. The volatile nonaqueous electrolyte system used with a normal electroosmotic flow polarity also provided an optimal separation condition for the characterization of the analytes by mass spectrometry. When results were compared with reversed‐phase gradient and isocratic high‐performance liquid chromatography (HPLC) methods, the NACE method provided greater efficiency, achieving baseline resolution for all nine basic compounds in less than 30 min. The NACE method is suitable for use as a routine procedure for the rapid separation and characterization of basic compounds and is a viable alternative to HPLC for the separation of a wide range of pharmaceutical drugs.
Single‐nucleotide polymorphism analysis by allele‐specific extension of fluorescently labeled nucleotides in a microfluidic flow‐through device
Authors: Russom Aman , Ahmadian Afshin , Andersson Helene , Nilsson Peter , Stemme Göran 
Published: March 2003

AbstractWe describe a microfluidic approach for allele‐specific extension of fluorescently labeled nucleotides for scoring of single‐nucleotide polymorphism (SNP). The method takes advantage of the fact that the reaction kinetics differs between matched and mismatched configurations of allele‐specific primers hybridized to DNA template. A microfluidic flow‐through device for biochemical reactions on beads was used to take advantage of the reaction kinetics to increase the sequence specificity of the DNA polymerase, discriminating mismatched configurations from matched. The volume of the reaction chamber was 12.5 nL. All three possible variants of an SNP site at codon 72 of the p53 gene were scored using our approach. This work demonstrates the possibility of scoring SNP by allele‐specific extension of fluorescently labeled nucleotides in a microfluidic flow‐through device. The sensitive detection system and easy microfabrication of the microfluidic device enable further miniaturization and production of an array format of microfluidic devices for high‐throughput SNP analysis.
An interface chip connection between capillary electrophoresis and thermal lens microscope
Authors: Uchiyama Kenji , Hibara Akihide , Sato Kiichi , Hisamoto Hideaki , Tokeshi Manabu , Kitamori Takehiko 
Published: March 2003

AbstractA thermal lens microscope (TLM) detection of capillary electrophoresis (CE) utilizing microchip technology was developed. Fused‐silica capillaries with an inner diameter of 50 μm were directly connected to a microchannel in a microchip. The detection limit by TLM was estimated as 2.8×10‐7 absorbance by measuring pure water. The detection limit of derivatized amino acids determined by CE‐TLM was estimated as 2.4×10‐8 M, which was 100 times lower than that of conventional absorbance detection.
The mitochondrial proteins of the neuroblastoma cell line IMR‐32
Authors: Fountoulakis Michael , Schlaeger Ernst‐Jürgen 
Published: March 2003

AbstractMitochondrial proteins exert important functions in biological pathways, particularly they are involved in apoptotic processes. We applied proteomics technologies to analyze the mitochondrial proteins of the neuroblastoma cell line IMR‐32, which is often used in apoptosis studies. The proteins were analyzed by two‐dimensional (2‐D) electrophoresis followed by matrix‐assisted laser desorption/ionization‐mass spectrometry (MALDI‐MS). 185 different gene products were identified, of which approximately 55% were enzymes with a broad spectrum of catalytic activities. Sixteen proteins were detected only in this preparation, the others have been detected in two or more protein samples analyzed by MS in our laboratory. The 16 unique gene products were represented by one spot each, whereas most of the frequently detected proteins were represented by multiple spots. In average, approximately 5–10 spots corresponded to one gene product. For two thirds of the proteins identified, an annotation exists in the SWISS‐PROT database about their subcellular location. They are mainly described as mitochondrial, 8 as endoplasmic reticulum, 3 as peroxisomal and only 12 low‐abundance proteins are described as cytosolic proteins. The list includes about 30 unknown, hypothetical or poorly described gene products. Some of them are represented by strong spots and the present study shows that they are indeed expressed and are localized in the mitochondria.
Capillary electrophoresis and fluorescence studies on molecular beacon‐based variable length oligonucleotide target discrimination
Authors: Ramachandran Akhilesh , Zhang Minquan , Goad David , Olah Glenn , Malayer Jerry R. , El Rassi Ziad 
Published: March 2003

AbstractMolecular beacons (MBs) are oligonucleotide probes having a compact hairpin structure, with a fluorophore attached to one end and a quencher molecule attached to the other end. In its native state, the fluorophore is quenched by virtue of its proximity to the quencher molecule. Upon hybridization with its complementary oligonucleotide target, fluorescence is elicited due to a conformational change that results in separation of the fluorophore and quencher molecule. The present study describes the hybridization interaction of an MB to various complementary target sequences. The effects of temperature and length of complementary target sequences on hybridization were investigated using capillary electrophoresis and solution‐based fluorescence techniques. Hybridization efficiency was dependent on the ability of the target sequences to destabilize the stem region by binding directly to the stem region. Optimal hybridization occurred between 40 and 50°C for all targets tested, with the true target forming a more stable hybrid complex.
Insoluble eggshell matrix proteins – their peptide mapping and partial characterization by capillary electrophoresis and high‐performance liquid chromatography
Authors: Mikšík Ivan , Charvátová Jana , Eckhardt Adam , Deyl Zdeněk 
Published: March 2003

AbstractAvian eggshell matrix proteins were studied by two analytical approaches. Peptide mapping was done by trypsin and pepsin followed by collagenase cleavage; analyses were carried out by capillary electrophoresis and reversed‐phase high‐performance liquid chromatography (HPLC). Comparison of peptide maps obtained by both methods revealed a complex mixture of peptides in the insoluble layers of the eggshell; it was concluded that there are at least three different insoluble protein/peptide layers in the avian eggshell (cuticle, palisade, and mammillary layer). Partial characterization of peptides in each layer was made by HPLC‐mass spectrometry analysis. There is an evidence that the eggshell insoluble proteins contain species susceptible to collagenase cleavage, however, the sequences split by this enzyme probably are not those typical for the main triple‐helical core of collagenous proteins. It is proposed that the action of collagenase upon eggshell proteins is caused by the side effect of collagenase described previously with synthetic peptides. Some of the proteins present are probably glycosylated. Fatty acid content in the insoluble eggshell layers (after decalcification) was in the range of 2–4% (which reflected both lipid and lipoproteins bound fatty acids). Porphyrin pigments are dominant in the cuticle layer.
Analysis of micronuclei in peripheral blood lymphocytes of traffic wardens: Effects of exposure, metabolic genotypes, and inhibition of excision repair in vitro by ARA‐C
Authors: Leopardi P. , Zijno A. , Marcon F. , Conti L. , Carere A. , Verdina A. , Galati R. , Tomei F. , Baccolo T.P. , Crebelli R. 
Published: March 2003

AbstractThe cytokinesis‐block micronucleus (MN) assay in peripheral lymphocytes was used to assess the genetic effects of the occupational exposure to traffic fumes in policemen from the Municipality of Rome. The study population consisted of 192 subjects engaged in traffic control (exposed, 134 subjects), or in office work (controls, 58 subjects). Groups were balanced for age, gender, and smoking habits. The average benzene exposure during the workshift was 9.5 and 3.8 μg/m3 in exposed individuals and controls, respectively. All subjects were genotyped for CYP1A1, CYP2E1, GSTM1, GSTT1, and DT‐diaphorase polymorphisms. The incidence of micronuclei and micronucleated cells was recorded in 1,000 binucleated cells harvested 66 hr after mitogen stimulation. Regression analysis of data showed that MN frequency was mainly modulated by the age (P = 0.001) and gender (P = 0.001) of the study subjects (relatively higher in the elderly and females), whereas it was unaffected by the occupational exposure to traffic fumes and smoking habits. A weak (P = 0.02) association between lower MN frequency and the GSTM1 null genotype was also observed. In order to improve the sensitivity of the method to excision‐repairable lesions, a modified protocol, with exposure of cells to the repair inhibitor cytosine arabinoside (Ara‐C) during the first 16 hr of growth, was applied to 78 subjects (46 exposed and 32 controls). The results confirmed the higher MN frequency in females (P < 0.05), but failed to demonstrate any significant effect of chemical exposure (occupational or related to smoking habits). When the frequency of MN induced by Ara‐C (i.e., spontaneous values subtracted) was considered, a significant inverse correlation with age was observed (P = 0.005), possibly related to the age‐dependent decrease in repair proficiency. Environ. Mol. Mutagen. 41:126–130, 2003. © 2003 Wiley‐Liss, Inc.
Estimation of erosion and deposition volumes in a large, gravel‐bed, braided river using synoptic remote sensing
Authors: Lane Stuart N. , Westaway Richard M. , Murray Hicks D. 
Published: March 2003

AbstractSystem‐scale detection of erosion and deposition is crucial in order to assess the transferability of findings from scaled laboratory and small field studies to larger spatial scales. Increasingly, synoptic remote sensing has the potential to provide the necessary data. In this paper, we develop a methodology for channel change detection, coupled to the use of synoptic remote sensing, for erosion and deposition estimation, and apply it to a wide, braided, gravel‐bed river. This is based upon construction of digital elevation models (DEMs) using digital photogrammetry, laser altimetry and image processing. DEMs of difference were constructed by subtracting DEM pairs, and a method for propagating error into the DEMs of difference was used under the assumption that each elevation in each surface contains error that is random, independent and Gaussian. Data were acquired for the braided Waimakariri River, South Island, New Zealand. The DEMs had a 1·0 m pixel resolution and covered an area of riverbed that is more than 1 km wide and 3·3 km long. Application of the method showed the need to use survey‐specific estimates of point precision, as project design and manufacturer estimates of precision overestimate a priori point quality. This finding aside, the analysis showed that even after propagation of error it was possible to obtain high quality DEMs of difference for process estimation, over a spatial scale that has not previously been achieved. In particular, there was no difference in the ability to detect erosion and deposition. The estimates of volumes of change, despite being downgraded as compared with traditional cross‐section survey in terms of point precision, produced more reliable erosion and deposition estimates as a result of the large improvement in spatial density that synoptic methods provide. Copyright © 2003 John Wiley & Sons, Ltd.