bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pattern recognition receptors and differentiation antigens define murine myeloid cell heterogeneity ex vivo
Authors: Taylor Philip R. , Brown Gordon D. , Geldhof Anja B. , Martinez‐Pomares Luisa , Gordon Siamon 
Published: July 2003

AbstractRecruitment of myeloid cells during inflammatory reactions plays an important role in the propagation and resolution of inflammation. However, the identification and characterization of these cells in mice has been hampered by cellular heterogeneity at the functional and phenotypic level. We have defined criteria for the rapid flow‐cytometric identification of monocytes (Mo), macrophages (MΦ), neutrophils (Neu) and eosinophils (Eos) in murine tissues using novel and established myeloid markers. These criteria were applied to the study of naive mice and mice with experimentally induced inflammation, both local and systemic, and also to a murine model of tumor progression. We show that the murine 7/4 antigen and the β‐glucan receptor, Dectin‐1, are particularly useful for the sub‐division of myeloid cells into individual populations, even when inflammatory conditions modulate their surface expression. Furthermore, 7/4 expression allows distinction between Mo recently recruited to a site and the resident cells already present. These studies highlight the heterogeneity of the murine Mo/MΦ‐lineage, define an extended phenotype for murine myeloid cells and greatly facilitate the ex vivo characterization of these cells during very different models of inflammation.
Mini‐review Activation‐induced cytidine deaminase: a dual role in class‐switch recombination and somatic hypermutation
Authors: Durandy Anne 
Published: July 2003

AbstractMaturation of the antibody repertoire is mediated by two different mechanisms: class‐switch recombination (CSR) and somatic hypermutation (SHM). These two processes are T cell dependent and occur in the germinal centers of secondary lymphoid organs. CSR leads to the production of antibodies of different isotypes whereas SHM leads to the selection of B cells expressing a BCR with high affinity for antigen. The activation‐induced cytidine deaminase (AID) was recently shown to play a key role in these two mechanisms, demonstrating for the first time that these maturation processes share a common mechanism. There is evidence that AID is involved in the somatic DNA alterations required for CSR and SHM. The mechanism of action of AID is unclear. As AID and APOBEC‐1 display a sequence similarity, AID may act as an RNA‐editing enzyme. However, the immunological abnormalities observed in uracil‐N glycosylase deficiency in a recent study indirectly suggest that AID may edit DNA directly.
Allosteric Manipulation of Photoexcited State Relaxation in a Series of RuII(bpy)2(bipyridine−crown ethers)
Authors: Dutta Subodh K. , Gan Daqing , Perkovic Marc W. 
Published: July 2003

AbstractA series of ruthenium(II) crown ether complexes containing 4‐, 5‐, or 6‐oxygen crowns tethered to a bipyridine at the 3,3′ position were prepared and examined for their ability to act as luminescent sensors. The complexes [(bpy)2Ru(2,2′‐bipyridine‐3,3′‐16‐crown‐4)](PF6)2 and [(bpy)2Ru(2,2′‐bipyridine‐3,3′‐19‐crown‐5)](PF6)2 were characterized by X‐ray crystallography. The 4‐oxygen crown crystallizes in the P$\bar 1$
space group. The 5‐oxygen crown crystallizes in the P$\bar 1$
space group. In both complexes, the inter‐pyridine ring angle in the tethered bipyridine is twisted substantially away from 0°. Coordination of a heavy metal ion such as Pb2+ by the crown ether, and the geometric changes that result, were examined by UV/Vis, luminescence and NMR spectroscopy. The results show that there is a weak allosteric interaction between the Pb2+ ion and the Ru complexes, and that this interaction alters the luminescent behavior of the Ru complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Chiral [(Dialkylamino)methyl](phospholyl)ferrocene Ligands as a New Class of 1,2‐Disubstituted Ferrocene Ligands
Authors: Mourgues Sophie , Serra Daniel , Lamy Franck , Vincendeau Sandrine , Daran Jean‐Claude , Manoury Eric , Gouygou Maryse 
Published: July 2003

AbstractAn efficient synthesis of new chiral [(dialkylamino)methyl](phospholyl)ferrocenes in an enantiomerically pure form has been developed. These new chiral N,P ligands have been tested in the palladium‐catalyzed allylic substitution reaction. High activities and moderate enantioselectivities (up to 67% ee) were observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
P‐Modular Homochiral Bis(phosphanes) with 1,2‐Disubstituted Cyclopentane Backbones in Asymmetric Hydrogenation
Authors: Dahlenburg Lutz 
Published: July 2003

AbstractThe review surveys synthetic aspects of a class of bidentate phosphanes based on the trans‐1,2‐disubstituted cyclopentane framework and the application of such ligands in transition‐metal‐catalyzed enantioselective hydrogenation. In particular, we address the preparative potential of the isomerically pure multi‐purpose P−H and P−Cl reagents (R,R)‐ and (S,S)‐C5H8(PX2)2 (X = H, Cl), which can serve to construct a family of optically active bis(phosphanes) with structural components (“modules”) that are easily and systematically interchanged. The so‐designed chelate ligands allow access to rhodium catalysts with stereodiscriminating properties, depending on parameters such as (i) presence of P‐substituents that are equal or pairwise different in steric demand, (ii) spatial orientation of such substituents as defined by the endo‐ and exo‐chelate P−C−C−P and P−Rh−P−C torsion angles, and (iii) existence of C‐ and P‐chirogenic stereoelements in matched (or mismatched) combination. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis, Crystal and Magnetic Structure of the Double Perovskites A2NiMoO6 (A = Sr, Ba): A Neutron Diffraction Study
Authors: Martínez‐Lope María J. , Alonso José A. , Casais María T. 
Published: July 2003

AbstractA2NiMoO6 (A = Sr, Ba) perovskites have been prepared in polycrystalline form by thermal treatment, in air, of previously decomposed citrate precursors. These materials have been studied by X‐ray (XRD) and neutron powder diffraction (NPD) data. At room temperature, the crystal structure is tetragonal, space group I4/m, for Sr2NiMoO6 and for Ba2NiMoO6 the crystal structure is cubic, space group Fm$\bar 3$
m. Both perovskites contain divalent Ni cations. The low temperature antiferromagnetic ordering has been followed from sequential neutron diffraction data. Peaks of magnetic origin appear in the NPD patterns below temperatures of TN = 81.2 K and TN = 64.3 K for the Sr and Ba compounds, respectively. The magnetic structures are defined by a propagation vector k = (1/2,0,1/2) for Sr2NiMoO6 and k = (1/2,1/2,1/2) for Ba2NiMoO6. The refined magnitude of the Ni magnetic moments also suggests a divalent oxidation state with S = 1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Great Framework Variation of Polymers in the Manganese(II) Maleate/α,α′‐Diimine System: Syntheses, Structures, and Magneto‐Structural Correlation
Authors: Ma Chengbing , Chen Changneng , Liu Qiutian , Chen Feng , Liao Daizheng , Li Licun , Sun Licheng 
Published: July 2003

AbstractThree novel manganese(II) coordination polymers, [Mn (maleate)(phen)]n (1; phen = 1,10‐phenanthroline), [Mn(maleate)(phen)]n·nH2O (2), and [Mn(maleate)(bpy)]n (3; bpy = 2,2′‐bipyridine), have been synthesized by treatment of Mn2+ with maleic acid with participation of chelate diimine ligands, and have been identified by single‐crystal X‐ray diffraction to have either one‐dimensional (1D) zigzag chain structures (1 and 2) or a two‐dimensional (2D) sinuous layer structure (3). Each maleate dianion coordinates to three Mn centers, in different bridging modes (syn‐anti in 1 and 2, syn‐syn and anti‐anti in 3). These compounds represent an interesting example of structural topology variation from 1D to 2D mediated by chemically similar auxiliary chelate ligands. Variable‐temperature magnetic susceptibility measurements show weak anti‐ferromagnetic exchange interactions between the adjacent MnII ions, with J = −0.06 cm−1 (2) and J = −1.3 cm−1, zJ′ = −0.27 cm−1 (3). The differences in the magnitudes of these coupling interactions agree well with the nature of the carboxylate‐bridging coordination of maleate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Lindqvist‐Type (Aryldiazenido)polyoxomolybdates − Synthesis, and Structural and Spectroscopic Characterization of Compounds of the Type (nBu4N)3[Mo6O18(N2Ar)]
Authors: Bustos Carlos , Hasenknopf Bernold , Thouvenot René , Vaissermann Jacqueline , Proust Anna , Gouzerh Pierre 
Published: July 2003

AbstractA series of aryldiazenido compounds of the type (nBu4N)3[Mo6O18(N2Ar)] have been prepared by treatment of (nBu4N)4[Mo8O26] with the appropriate arylhydrazines in acetonitrile or in methanol. All these compounds are isostructural. Two members of the series, the o‐nitro and the p‐carboxy derivatives, have been characterized by single‐crystal X‐ray diffraction. The aryl ring in the first anion lies in a mirror plane of the polyoxometalate, while in the second one it is tilted, allowing hydrogen bonding between the carboxylic acid function and a neighbouring anion. The aryldiazenido ligands exhibit the characteristic features of the singly bent coordination mode with short Mo−N and N−N bond lengths indicative of multiple bond character. The compounds have been characterized by 95Mo and 17O NMR spectroscopy in acetonitrile. Their spectra indicate C4v symmetry, and hence stereochemical nonrigidity in solution. The 95Mo chemical shifts are mainly determined by variation in the paramagnetic shielding term, σpara. The strongly deshielded resonance of the MoII centre spans a large range (600−1100 ppm). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Electrodeposition of Lead at Boron‐Doped Diamond Film Electrodes: Effect of Temperature
Authors: Prado César , Wilkins Shelley J. , Gründler Peter , Marken Frank , Compton Richard G. 
Published: July 2003

AbstractThe electrodeposition of lead on boron‐doped diamond has been studied with a view to identifying the fundamental parameters controlling the sensitivity and lower detection limit in anodic stripping voltammetry. Chronoamperometric transients are used to explore the deposition, indicating a progressive growth mechanism confirmed by ex situ AFM images. Linear sweep ASV experiments show a threshold concentration of ca 10−6 M below which no lead is detected; this is attributed to the need for nucleation of the solid phase on the electrode. Experiments with variable temperature show that this threshold can be usefully lowered at elevated temperatures.
A Cholesterol Biosensor Based on Entrapment of Cholesterol Oxidase in a Silicic Sol‐Gel Matrix at a Prussian Blue Modified Electrode
Authors: Li Jianping , Peng Tuzhi , Peng Yuqiang 
Published: July 2003

AbstractA cholesterol biosensors fabricated by immobilization of cholesterol oxidase (ChOx) in a layer of silicic sol‐gel matrix on the top of a Prussian Blue‐modified glassy carbon electrode was prepared. It is based on the detection of hydrogen peroxide produced by ChOx at −0.05 V. The half‐lifetime of the biosensor is about 35 days. Cholesterol can be determined in the concentration range of 1×10−6−8×10−5 mol/L with a detection limit of 1.2×10−7 mol/L. Normal interfering compounds, such as ascorbic acid and uric acid do not affect the determination. The high sensitivity and outstanding selectivity are attributed to the Prussian Blue film modified on the sensor.
The Current Usage of Selectivity Coefficients for the Characterization of Ion‐Selective Electrodes. A Critical Survey of the 2000/2001 Literature
Authors: Maccà Carlo 
Published: July 2003

AbstractThe articles describing new ion‐selective electrodes published during the years 2000/2001 in eight leading analytical chemistry journals have been surveyed. Compliance with the IUPAC recommendations of the procedures used for characterizing the selectivity of the new electrodes has been checked. It was found that the information accompanying the selectivity data obtained according to the procedures recommended by IUPAC or their variations was frequently insufficient for interpreting of the electrode behavior and comparing with other sets of data, thus reducing the significance of the values provided. Some criteria for improving the communication between researchers in the field are suggested.
A single‐strand conformation polymorphism method by capillary electrophoresis with laser‐induced fluorescence for detection of the T1151A mutation in hMLH1 gene
Authors: Shi Xianzhe , Xu Guowang , Zhao Chunxia , Ma Jianmei , Zhang Yan , Lv Shen , Yang Qing 
Published: July 2003

AbstractMutation of hMLH1 gene plays an important role in human tumorigenesis. A highly sensitive single‐strand conformation polymorphism (SSCP) method for detection of the T1151A mutation in exon 12 of the hMLH1 gene was for the first time developed employing laser‐induced fluorescence capillary electrophoresis (LIF‐CE). Effects of the concentration of linear polyacrylamide solution, running temperature, running voltage and the addition of glycerol on SSCP analysis were investigated, and the optimum separation conditions were defined. Thirty colorectal cancer patients and eight lung cancer patients were screened and the T1151A mutation was found in four of them. Based on CE‐sequencing the mutation was further confirmed. To our knowledge, this is for the first time that the T1151A mutation is found in lung cancer. Our method is simple, rapid, and highly sensitive and is well suited to the analysis of large numbers of clinical samples.
Two problematic human polymorphic Alu insertions
Authors: Luis Javier R. , Terreros Maria C. , Martinez Laisel , Rojas Dina , Herrera Rene J. 
Published: July 2003

AbstractAnalysis of two previously described polymorphic Alu insertions (Sb19.3 and NBC3) in world‐wide human populations generated genotypic frequencies grossly in violation of Hardy‐Weinberg equilibrium expectations. GenBank searches at the National Center for Biotechnology Information (NCBI) and sequencing analyses revealed that samples homozygous for the Sb19.3 Alu insertion amplify a band indistinguishable in size to the lack of insertion amplicon, corresponding to a paralogous locus on chromosome 4. This locus displays a very similar sequence (84%) to that flanking the Sb19.3 Alu insertion located at chromosome 19. Moreover, we have determined that NBC3, a different Alu insertion, is not located in the pseudoautosomal region of the Y‐chromosome, as previously reported, but in position Yq11.2. Also, the band that mimics the lack of insertion amplicon corresponds to a paralogous locus located at chromosome X with a similarity of 92% to the sequence flanking the NBC3 Alu insertion. Finally, the utilization of newly designed primers avoided amplification from the paralogous loci and allowed a reliable assignation of genotypes for both loci. Unlike previously reported, using our new primers the Y‐specific locus NBC3 was found not to be polymorphic in the populations analyzed.
Molecular epidemiological investigation of Ascaris genotypes in China based on single‐strand conformation polymorphism analysis of ribosomal DNA
Authors: Peng Weidong , Yuan Keng , Zhou Xianmin , Hu Min , Abs EL‐Osta Youssef G. , Gasser Robin B. 
Published: July 2003

AbstractUsing a single‐strand conformation polymorphism‐based approach, we investigated nucleotide variation in part of the first internal transcribed spacer (pITS‐1) of nuclear ribosomal DNA within and among a large number of Ascaris individuals from humans and pigs from six endemic regions in China, and examined the frequency of the different genotypes of Ascaris in relation to host species and geographical origin. Five different SSCP genotypes (G1–G5) were recorded for human Ascaris (n = 486), of which three (genotypes G1–G3) were detected for pig Ascaris (n = 329). Of the five Ascaris genotypes detected, genotype G1 predominantly infected humans (∼63–74%) whereas genotype G3 infected mainly pigs (∼79–86%), indicating that each of these genotypes has a particular host affiliation. In contrast, the frequencies of the other three genotypes was substantially lower for each of the two host species. The findings also suggested that the rate of cross infection of Ascaris between humans and pigs is relatively low and that gene flow between the predominant genotypes is limited, consistent with previous proposals for endemic regions in other countries. While the nature and extent of nucleotide variation in the pITS‐1 (and the proposal of host affiliated Ascaris populations) may relate to “introgression” or “lineage sorting and retention of ancentral polymorphism”, other explanations are possible. Evidence of multiple pITS‐1 sequence types in some Ascaris individuals representing particular genotypes (e.g., G2 and G5) may suggest hybridization between human‐ and pig‐affiliated Ascaris. This aspect and the species status of Ascaris (from each host species) warrant future experimental testing, employing the pig/Ascaris model and the present electrophoretic approach.*
Study of the development of chemoresistance in melanoma cell lines using proteome analysis
Authors: Sinha Pranav , Poland Julia , Kohl Sandro , Schnölzer Martina , Helmbach Heike , Hütter Gero , Lage Hermann , Schadendorf Dirk 
Published: July 2003

AbstractMalignant melanomas have poor prognosis since treatment with anti‐neoplastic agents is mostly ineffective. The biological mechanisms of this strong intrinsic therapy resistance are unknown. In order to identify new molecular factors potentially associated with the drug‐resistant phenotype of malignant melanoma, a panel of human melanoma cell variants exhibiting low and high levels of resistance to four commonly used anticancer drugs in melanoma treatment, i.e., vindesine, etoposide, cisplatin, and fotemustine, was characterized using proteomic tools (two‐dimensional electrophoresis for protein fractionation and matrix assisted laser desorption/ionization‐time of flight (MALDI‐TOF)‐mass spectrometry for protein identification). In the neutral and weak acidic milieu (pH 4.0–8.0) a total number of 14 proteins showed alterations in expression whereas 20 proteins were differentially expressed in the basic milieu (pH 8.0–11.0). Besides proteins with unknown physiologic function, several factors were identified that show chaperone activity. Moreover, proteins involved in drug detoxification, metabolism, and regulation of apoptotic pathways could be identified. The possible role of these proteins in the development of chemoresistance is discussed, although detailed functional tests with these proteins have still to be performed. Nevertheless, it is clear that this proteomic approach for studying chemoresistance phenomena is a prerequisite before further investigation can yield insight into the biology and development of drug resistance in malignant melanoma.
Polyacrylamide gel electrophoresis followed by sodium dodecyl sulfate gradient polyacrylamide gel electrophoresis for the study of the dimer to monomer transition of human transthyretin
Authors: Altland Klaus , Winter Pia 
Published: July 2003

AbstractFamilial amyloidotic polyneuropathy (FAP) is caused by mutations which destabilize transthyretin (TTR) and facilitate the aggregation into extracellular amyloid fibrils preferentially in peripheral nerve and heart tissues. Therapeutic and preventive trials for FAP at the plasma TTR level require a careful study of the destabilization of TTR under variable conditions. We have developed a simple double one‐dimensional (D1‐D) electrophoretic procedure with polyacrylamide gel electrophoresis (PAGE) followed by sodium dodecylsulfate (SDS) gradient PAGE to study the dimer to monomer transition. TTR is first isolated by PAGE from other plasma proteins. The gel strip containing the TTR fraction is incubated in 2% SDS under varying conditions of temperature, buffer composition, pH, and additives like urea and/or a sulfhydryl‐reactive agent, followed by SDS‐gradient PAGE for the separation of TTR dimers and monomers. We demonstrate that an unidirectional dimer to monomer transition of normal TTR is achieved at 70–80°C in neutral to mild alkaline buffers or at 37°C and slightly acidic pH (6–7). Addition of urea favors the transition into monomers. Amyloidogenic mutations like amyloidogenic TTR (ATTR)‐V30M or ATTR‐I107V favor the transition into monomers in buffer systems close to the physiological pH of human plasma. We conclude that this finding has to be considered by any hypothesis on ATTR‐derived amyloidogenesis.
Thiol‐reactive dyes for fluorescence labeling of proteomic samples
Authors: Tyagarajan Kamala , Pretzer Elizabeth , Wiktorowicz John E. 
Published: July 2003

AbstractCovalent derivatization of proteins with fluorescent dyes prior to separation is increasingly used in proteomic research. This paper examines the properties of several commercially available iodoacetamide and maleimide dyes and discusses the conditions and caveats for their use in labeling of proteomic samples. The iodoacetamide dyes BODIPY TMR cadaverine IA and BODIPY Fl C1‐IA were highly specific for cysteine residues and showed little or no nonspecific labeling even at very high dye:thiol ratios. These dyes also showed minimal effects on pI's of standard proteins. Some iodoacetamide dyes, (5‐TMRIA and eosin‐5‐iodoacetamide) and some maleimide dyes (ThioGlo I and Rhodamine Red C2 maleimide) exhibited nonspecific labeling at high dye:thiol ratios. Labeling by both iodoacetamide and maleimide dyes was inhibited by tris(2‐carboxyethyl)phosphine (TCEP); interactions between TCEP and dye were also observed. Thiourea, an important component of sample solubilization cocktails, inhibited labeling of proteins with iodoacetamide dyes but not with maleimide dyes. Maleimide dyes may serve as an alternative for labeling proteins where it is essential to have thiourea in the solubilization buffer. Covalent derivatization by BODIPY TMR cadaverine IA, BODIPY Fl C1‐IA or Rhodamine Red C2 maleimide was also demonstrated to be compatible with in‐gel digestion and peptide mass fingerprinting by matrix assisted laser desorption/ionization‐mass spectrometry and allowed successful protein identification.
Nonconventional synthesis and characterization of ultrahigh‐molar‐mass polyacrylamides
Authors: Cretich Marina , Chelaru Carmen , Pirri Giovanna , Levi Marinella , Clerici Gigliola , Chiari Marcella 
Published: July 2003

AbstractIn spite of the significant progresses in the field of replaceable sieving matrices for separating DNA in capillary electrophoresis (CE), an intense research activity is still going on to improve the separation of large size DNA sequencing fragments. There are evidences, both from experimental and theoretical sides that the resolution of these fragments, at the single base, requires the use of sieving matrices comprised of long chain linear polymers. In the separation of DNA fragments by CE are of upmost importance: (i) the complete solubility of the polymer, (ii) the linearity of the chain, (iii) the achievement of ultrahigh viscosity in dilute solutions. The aim of this work is the synthesis of ultrahigh‐molecular‐weight polymers which possess the three requirements mentioned above by employing a nonconventional method. We demonstrate that the sieving performance of polyacrylamide is directly correlated to its intrinsic viscosity.