bluuebunny/crossref_metadata_2025_split huggingface dataset:
Guanine Oxidation by Electron Transfer: One‐ versus Two‐Electron Oxidation Mechanism
Authors: Kupan Adam , Saulière Aude , Broussy Sylvain , Seguy Christel , Pratviel Geneviève , Meunier Bernard 
Published: December 2005

AbstractThe degeneracy of the guanine radical cation, which is formed in DNA by oxidation of guanine by electron transfer, was studied by a detailed analysis of the oxidation products of guanine on oligonucleotide duplexes and by labeling experiments. It was shown that imidazolone, the major product of guanine oxidation, is formed through a one‐electron oxidation process and incorporates one oxygen atom from O2. The formation of 8‐oxo‐7,8‐dihydroguanine by a two‐electron oxidation process was a minor pathway. The two‐electron oxidation mechanism was also evidenced by the formation of a tris(hydroxymethyl)aminomethane adduct.
Extended Electrochemical Windows Made Accessible by Room Temperature Ionic Liquid/Organic Solvent Electrolyte Systems
Authors: Buzzeo Marisa C. , Hardacre Christopher , Compton Richard G. 
Published: December 2005

AbstractThe electrochemical windows of acetonitrile solutions doped with 0.1 M concentrations of several ionic liquids were examined by cyclic voltammetry at gold and platinum microelectrodes. These results were compared with those observed in the commonly used 0.1 M tetrabutylammonium perchlorate/acetonitrile system as well as with neat ionic liquids. The use of a trifluorotris(pentafluoroethyl)phosphate‐based ionic liquid, specifically, as supporting electrolyte in acetonitrile solutions affords a wider anodic window, which is attributed to the high stability of the anionic component of these intrinsically conductive and thermally robust compounds.
Role of the monomeric GTPase Rho in hematopoietic progenitor cell migration and transplantation
Authors: Göttig Stephan , Möbest Dietrich , Rüster Brigitte , Grace Bithiah , Winter Sylvia , Seifried Erhard , Gille Jens , Wieland Thomas , Henschler Reinhard 
Published: December 2005

AbstractTo investigate the role of the monomeric guanosine triphosphatase (GTPase) Rho on migration of hematopoietic progenitor cells (HPC), we employed different clostridial toxins which inhibit the Rho family of GTPases. Pretreatment with C2I‐C3, a cell‐accessible C3 transferase fusion protein that targets Rho, increased chemokinetic migration of the factor‐dependent multipotent cell line Factor Dependent Cell Paterson with mixed lineage differentiation potential (FDCP‐mix) and of primary lineage marker‐depleted HPC in vitro. In contrast, treatment with lethal toxin (LT) from Clostridium sordellii, which predominantly inactivates Rac, and with toxin B from C. difficile, which inactivates Rho, Rac and Cdc42, decreased in vitro migration. When HPC pretreated with LT or toxin B were transplanted into mice, homing to the bone marrow was impaired, whereas C2I‐C3 treatment did not alter HPC homing. However, in a competitive hematopoietic repopulation experiment in C57BL/6 mice, pretreatment of bone marrow cells with any of the inhibitors, including the Rho inhibitor C2I‐C3, resulted in suppressed donor‐type hematopoiesis. Our data indicate that whereas Rac supports HPC cell cycling, migration, short‐term homing and hematopoietic regeneration, Rho coordinates down‐regulation of HPC migration and is required for hematopoietic regeneration.
A mutant human IgG molecule with only one C1q binding site can activate complement and induce lysis of target cells
Authors: Michaelsen Terje E. , Thommesen John E. , Ihle Oistein , Gregers Tone F. , Sandin Randi H. , Brekke Ole Henrik , Sandlie Inger 
Published: December 2005

AbstractThere are potentially two binding sites for C1q on IgG, one on each CH2 domain of the gamma heavy chains, close to the lower hinge region. It is not clear whether the presence and involvement of both the C1q binding sites is necessary to induce the activation signal of human IgG. In order to clarify this issue, we made a hybrid mutant IgG1/IgG3 molecule where the IgG1 half of the molecule was made unable to activate complement through the introduction of a P329A mutation. The IgG3 half of the molecule was mutated to harbor a hinge region identical to that of IgG1, and for detection a peptide tag derived from p21ras was introduced into the FG loop of the CH1 domain. The hybrid IgG1P329A/IgG3h1‐ras molecules were isolated by Protein A affinity chromatography and shown to activate complement and induce complement‐mediated lysis at the same levels as wild‐type IgG1 and IgG3h1‐ras molecules. Thus, one C1q binding site per IgG is sufficient to induce activation. Wild‐type human IgG molecules might also normally expose only one C1q binding site as already shown for interaction with FcγR, were IgG expose one binding site per molecule.
Influenza H2 haemagglutinin activates B cells via a MyD88‐dependent pathway
Authors: Marshall‐Clarke Stuart , Tasker Lynn , Buchatska Olena , Downes Joan , Pennock Joanne , Wharton Steve , Borrow Persephone , Wiseman David Z. 
Published: December 2005

AbstractInfluenza viruses are serious respiratory pathogens, responsible for half a million deaths each year. The viral surface haemagglutinin (HA) protein has been shown to be an important determinant of viral pathogenicity. HA is the virion attachment and fusion protein, and the major target for neutralizing antibodies; however, it is also involved in triggering innate responses that may have an important impact on the disease course. We have examined the role of the toll‐like receptor (TLR) family in innate responses to influenza virus and influenza HA. TLR7 has recently been found to mediate recognition of influenza RNA. Here, we show for the first time that influenza HA of the H2 subtype induces innate responses in murine B lymphocytes via a MyD88‐dependent pathway distinct from that involved in sensing viral RNA. We also show that inactivated influenza virus induces activation of human B cells. Our findings suggest that the molecule mediating these responses may be a novel member of the TLR family.
A transmembrane‐anchored rat RAE‐1‐like transcript as a ligand for NKR‐P2, the rat ortholog of human and mouse NKG2D
Authors: Savithri Balasubramanian , Khar Ashok 
Published: December 2005

AbstractNKG2D is a potent activating immunoreceptor that has been extensively characterized in NK cells and shown to lend costimulatory functions in CD8+ T cells under certain conditions. The list is growing of ligands for NKG2D, which are distantly related to MHC class I molecule and are often up‐regulated during cellular distress. Here, we describe the cloning of a novel (and incidentally the first) ligand for NKR‐P2, the rat ortholog of human and mouse NKG2D, termed as rat RAE‐1‐like transcript (RRLT). The newly identified ligand is homologous to mouse RAE‐1 family of proteins, but differs from them in being transmembrane anchored. The protein localizes to cell surface, and is expressed in a variety of tumor cell lines and tissues. Ectopic expression of the ligand induces NK cell activation, and renders the target cells susceptible to NK cell killing. In addition, the role of RRLT‐NKR‐P2 interaction in tumor killing has been demonstrated.
Crystal structure of HLA‐A*2402 complexed with a telomerase peptide
Authors: Cole David K. , Rizkallah Pierre J. , Gao Feng , Watson Neil I. , Boulter Jonathan M. , Bell John I. , Sami Malkit , Gao George F. , Jakobsen Bent K. 
Published: December 2005

AbstractHLA‐A*2402 is the most commonly expressed HLA allele in oriental populations. It is also widely expressed in the Caucasian population, making it one of, if not the most abundant HLA I types. In order to study its structure in terms of overall fold and peptide presentation, a soluble form of this HLA I (α1, α2, α3 and β2m domains) has been expressed, refolded and crystallized in complex with a cancer‐related telomerase peptide (VYGFVRACL), and its structure has been solved to 2.8 Å resolution. The overall structure of HLA‐A*2402 is virtually identical to other reported peptide‐HLA I structures. However, there are distinct features observable from this structure at the HLA I peptide binding pockets. The size and depth of pocket B makes it highly suitable for binding to large aromatic side chains, which explains the high prevalence of tyrosine at peptide position 2. Also, for HLA binding at peptide position 5, there is an additional anchor point, which allows the proximal amino acids to protrude out, providing a prominent feature for TCR interaction. Finally, pocket F allows the anchor residue at position 9 to be bound unusually deeply within the HLA structure.
Structural Relationships in High‐Nuclearity Heterobimetallic Bismuth‐Oxo Clusters (Eur. J. Inorg. Chem. 24/2005)
Authors: Mehring Michael , Paalasmaa Sanna , Schürmann Markus 
Published: December 2005

AbstractThe cover picture shows three heterobimetallic sodium‐bismuth‐oxo silanolates: [Bi10Na5O7(OH)6(OSiMe3)15] (2), [Bi15‐Na3O18(OSiMe3)12] (3) and [Bi14Na8O18(OSiMe3)14(thf)4] (4). These novel polynuclear metal‐oxo clusters were obtained in addition to the hexanuclear oxygen‐centred complex [Bi2Na4O(OSiMe3)8] (1), which represents a well‐known structural motif found in several heterometallic group 15/group 1 compounds. As result of the similar ionic radii of sodium and bismuth and the flexible coordination chemistry of these main group metals, the formation of a large variety of heterobimetallic molecular structures is conceivable. Structural relationships between the metal‐oxo silanolates are described and a comparison with other polynuclear bismuth‐oxo compounds is given in order to identify basic building blocks. The approach is envisaged to develop rational design strategies towards molecular bismuth‐containing precursors for heterometallic materials. Details are discussed in the article by M. Mehring et al. on p. 4891 ff.
Sulfite Determination at In Situ Plated Copper Modified Gold Ultramicroelectrode Arrays
Authors: Ordeig Olga , Banks Craig E. , del Campo F. Javier , Muñoz Francesc Xavier , Davis James , Compton Richard G. 
Published: December 2005

AbstractThe electroanalytical detection of sulfite has been explored at an in situ formed copper ultramicroelectrode array. The protocol is based upon the in situ deposition of copper at a gold ultramicroelectrode array of cubic geometry which consists of 256 ultramicroelectrodes which are 5 microns in radius and are separated from their nearest neighbor by 100 microns. The immobilized copper array is electrocatalytic for the electrochemical reduction of sulfur dioxide which is formed after protonation of sulfite at low pH values (<pH 2). A sensitivity and detection limit of 0.35 nA μM−1 and 6 μM respectively is shown to be possible in pH 2.5 using linear sweep voltammetry with a linear range observed from 20–500 μM.
Carotid intima‐media thickness in late‐onset major depressive disorder
Authors: Chen Cheng‐Sheng , Chen Cheng‐Chung , Kuo Yu‐Ting , Chiang I‐Chan , Ko Chih‐Hung , Lin Hsiu‐Fen 
Published: December 2005

AbstractBackgroundThis study explored whether patients with late‐onset major depressive disorder showed higher carotid artery intima‐medium thickness (IMT) and investigated the relationship between the IMT and white matter hyperintensities on magnetic resonance imaging (MRI) among patients.MethodsFourteen elderly patients with late‐onset major depressive disorder from a psychiatric outpatient clinic and 11 non‐depressed controls received a comprehensive psychiatric assessment, ultrasound IMT measurements of the carotid arteries, and cerebral MRI.ResultsThe carotid IMT was higher in the patient group vs the control group (1.26 ± 0.30 vs 1.00 ± 0.20 mm; t = 2.40, p < 0.03). The difference was more apparent in the common carotid artery (1.20 ± 0.32 vs 0.97 ± 0.13 mm; t = 2.31, p < 0.04). There was a high correlation (r = 0.55, p < 0.05) between the carotid IMT and white matter hyperintensities among patients with late‐onset major depressive disorder.ConclusionResults of this study suggest that atherosclerosis represented by the carotid IMT contributes to the development of late‐onset major depressive disorder. The findings support the vascular depression hypothesis. Copyright © 2005 John Wiley & Sons, Ltd.
Late‐life depression: the differences between early‐ and late‐onset illness in a community‐based sample
Authors: Janssen Joost , Beekman Aartjan T. F. , Comijs Hannie C. , Deeg Dorly J. H. , Heeren Thea J. 
Published: December 2005

AbstractBackgroundSeveral studies have described etiological and clinical differences between elderly depressed patients with early onset of their illness compared to late onset. While most studies have been carried out in clinical samples it is unclear whether the findings can be generalized to the elderly population as a whole. The aim of this study was to compare early‐onset (EOD) and late‐onset (LOD) depressive illness in a community‐based sample.MethodsLarge (n = 3107) representative sample of older persons (55–85 years) in the Netherlands. Two‐stage screen procedure to identify elderly with MDD. The Center for Epidemiologic Studies Depression scale (CES‐D) was used as a screen and the Diagnostic Interview Schedule (DIS) to diagnose MDD. Data on 90 older persons with early‐onset depression and 39 with late‐onset depression were available.ResultsThose with LOD were older, and more often widowed. Family psychiatric history, vascular pathology, and stressful early and late life events did not differ between groups. EOD subjects had more often double depression and more anxiety.ConclusionsIn a community‐based sample we did not detect clear differences in etiology and phenomenology between EOD and LOD. This discrepancy with reports from clinical samples could be due to selection bias in clinical studies. Consequently, all patients with late‐life depression deserve a diagnostic work‐up of both psychosocial and somatic risk factors and treatment interventions should be focused accordingly. Copyright © 2005 John Wiley & Sons, Ltd.
Epigenetic regulation of metallothionein‐i gene expression: Differential regulation of methylated and unmethylated promoters by DNA methyltransferases and methyl CpG binding proteins
Authors: Majumder Sarmila , Kutay Huban , Datta Jharna , Summers Dennis , Jacob Samson T. , Ghoshal Kalpana 
Published: December 2005

AbstractMetallothioneins (MTs) are a group of cysteine‐rich stress response proteins that scavenge reactive oxygen species and heavy metals. Recently, we have shown that MT‐I promoter is methylated and suppressed in some solid and liquid tumors and can be robustly activated following treatment with inhibitors of DNA methyltransferase (DNMT) and histone deacetylase (HDAC). Here, we have analyzed MT‐I chromatin structure in active, unmethylated (Hepa cells) and in repressed, methylated state (lymphosarcoma cells). Restriction enzyme accessibility assay showed that the MT‐I promoter has an open conformation in unmethylated state as opposed to refractory chromatin structure in methylated state. Positioning of nucleosomal arrays on the methylated promoter further confirmed the closed chromatin structure of the methylated promoter. Chromatin immunoprecipitation (ChIP) assay demonstrated that the unmethylated promoter is associated with K9‐acetyl, K4‐methyl, and S10‐phospho histone H3 whereas the methylated promoter is predominantly associated with K9‐methyl H3. HP1α that recognizes K9‐methyl H3 inhibited methylated MT‐1 promoter activity whereas closely related HP1γ repressed the promoter irrespective of its methylation status. Ubiquitously expressed DNA methyltransferase 1 (DNMT1) suppressed MT‐I promoter activity irrespective of its methylation status that does not require its catalytic activity. The DNMT1‐mediated repression of MT‐I promoter was relieved by trichostatin A, an HDAC inhibitor. Among the methyl CpG binding proteins, MBD2 and MBD4 specifically associated with the methylated promoter and inhibited its activity. In contrast, MBD1 and MeCP2 interacted with both promoters and suppressed the promoter activity irrespective of its methylation status. These results demonstrate that the methylated and unmethylated MT‐I promoter are differentially regulated by DNA methyltransferase and methyl‐CpG binding proteins, and DNMT1 could suppress MT promoter by a transcriptional mechanism independent of its enzymatic function. These studies suggest that the components of epigenetic machinery differentially regulate methylated and unmethylated MT‐I gene expression. J. Cell. Biochem. 97: 1300–1316, 2006. © 2005 Wiley‐Liss, Inc.
Ultrastructural and cytochemical aspects of the female gonad of Geoplana burmeisteri (Platyhelminthes, Tricladida, Terricola)
Authors: Falleni Alessandra , Lucchesi Paolo , Ghezzani Claudio , Silveira Marina , Gremigni Vittorio 
Published: December 2005

AbstractThe ultrastructure of the female gonad of the land planarian Geoplana burmeisteri was investigated by means of electron microscopy and cytochemical techniques. It consists of two small germaria located ventral to the intestine and of two irregular, lateral rows of vitelline follicles, both enveloped by a tunica composed of an extracellular lamina and an inner sheath of accessory cells. Accessory cell projections completely surround developing oocytes and vitellocytes. The main feature of oocyte maturation is the appearance of chromatoid bodies and the development of the rough endoplasmic reticulum (RER) and Golgi complexes. These organelles appear to be correlated with the production of egg inclusions of medium electron density, about 1.5–1.8 μm in diameter, which remain scattered in the ooplasm of mature oocytes. On the basis of cytochemical tests demonstrating their glycoprotein composition, these inclusions were interpreted as residual yolk globules. Vitellocytes are typical secretory cells with well‐developed RER and Golgi complexes that are mainly involved in the production of yolk globules and eggshell globules, respectively. Eggshell globules appear to arise from repeated coalescence of small Golgi‐derived vesicles and, at an intermediate stage of maturation, show a multigranular pattern. Later, after vesicle fusion, they reach a diameter of 1.3–1.6 μm when completely mature and show a meandering/concentric pattern, as is typical of the situation seen in most Proseriata and Tricladida. The content of yolk globules is completely digested by pronase, while the content of eggshell globules is unaffected. Mature vitellocytes contain, in addition, a large quantity of glycogen and lipid droplets as further reserve material. On the basis of the ultrastructural characteristics of the female gonad described above and in relation to the current literature, we conclude that G. burmeisteri appears to be more closely related to the freshwater triclads, in particular to members of the Dugesiidae, than to the marine triclads. J. Morphol. © 2005 Wiley‐Liss, Inc.
Molecular activity of sirolimus and its possible application in tuberous sclerosis treatment
Authors: Jozwiak Jaroslaw , Jozwiak Sergiusz , Oldak Monika 
Published: December 2005

AbstractSirolimus is one of the intensively investigated drugs with pluripotent activities. It binds to its intracellular receptor FKBP12 (FK506‐binding protein 12), a member of the family of FK506‐binding proteins, and inhibits the activity of mTOR, a serine/threonine kinase involved in numerous cell processes linked to cell growth control. The drug is currently registered for the prophylaxis of organ rejection and for use in coronary stents. However, unique characteristics of sirolimus make it a good candidate for anti‐cancer therapy. Indeed, phase II and III clinical studies in humans with several types of neoplasms are already under way. The review describes molecular activity of sirolimus and its analogs, characteristic for specific applications, in view of very recent advances involving tuberous sclerosis complex (TSC)‐mediated signaling pathways. Current studies with sirolimus performed in tuberous sclerosis animal models are presented. Possible application of sirolimus for treating tuberous sclerosis, disease caused by mutations of TSC proteins, is discussed. © 2005 Wiley Periodicals, Inc. Med Res Rev
Incorporation of selective population transfer and homo‐spin decoupling into selective one‐dimensional experiments
Authors: Uzawa Jun , Fujimoto Yasuo , Yoshida Shigeo 
Published: December 2005

AbstractThe incorporation of selective population transfer (SPT) and homo‐spin decoupling (HSD) into selective one‐dimensional (1D) experiments has been shown to be very useful in obtaining information on the elucidation of the structure of organic compounds. To demonstrate this, the determination of the relative configuration of the sugar moiety of Mi‐saponins has been presented. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and properties of organosoluble polynaphthalimides based on 1,4,5,8‐naphthalene tetracarboxylic dianhydride, 3,3‐bis[4‐(4‐aminophenoxy)phenyl]phthalide, and various aromatic diamines
Authors: Yang Chin‐Ping , Su Yu‐Yang , Wang Je‐Min 
Published: December 2005

AbstractTwo series of polynaphthalimides (PNIs), II and III, were prepared from 1,4,5,8‐naphthalene tetracarboxylic dianhydride with the usual aromatic diamines (Ia–Ih) or Ia, which was used as a soluble modifying agent, and Ib–Ih via a one‐stage process with high‐temperature condensation. Series II and III had inherent viscosities of 0.57–1.34 and 1.15–1.63 dL/g, respectively. IIa and most of the III series were soluble in 1‐methy‐2‐pyrrolidone and m‐cresol at 5–10 wt % and afforded transparent and tough films by m‐cresol solvent casting with a tensile strength in the range of 75–99 MPa. The glass‐transition temperature and softening temperature of these PNIs were in the ranges of 360–404 and 188–241 °C, respectively, and the 10% weight loss temperatures were above 495 °C, with more than a 44% char yield at 800 °C in nitrogen. These PNI films had dielectric constants of 4.14–6.46 (1 MHz), with moisture absorption in the range of 0.87–1.91 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 940–948, 2006
Exchange coupling across quasi‐amorphous Zr–Fe spacer
Authors: Smardz L. , Smardz K. , Niedoba H. 
Published: December 2005

AbstractFe/Zr/Fe trilayers with wedge‐shaped Zr interlayer were prepared using UHV (5 × 10–10 mbar) DC/RF magnetron sputtering. The planar growth and interface alloying of the Fe and Zr layers was confirmed in‐situ by X‐ray photoelectron spectroscopy. For a Zr layer thickness (d Zr) from 1 to 3 nm we have observed patch domains characteristic for antiferromagnetic interlayer exchange coupling. Results showed that the Fe sublayers are very weakly exchange coupled or decoupled for d Zr > 3 nm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature effects in a spin‐orbital model for manganites
Authors: Daghofer M. , Neuber D. R. , Oleś Andrzej M. , von der Linden Wolfgang 
Published: December 2005

AbstractWe study a two‐dimensional effective orbital superexchange model derived for strongly correlated eg electrons coupled to t 2g core spins in layered manganites. One finds that the ferromagnetic (FM) and antiferromagnetic (AF) correlations closely compete, and small changes of parameters can switch the type of magnetic order. For the same reason, spin order is easily destroyed with rising temperature, while alternating orbital correlations can persist to temperatures where FM order has already melted. A scenario for the AF phase observed in LaSrMnO4 is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transversal and longitudinal diffusion in polar disordered organic materials
Authors: Novikov Sergey V. , Malliaras George G. 
Published: December 2005

AbstractLongitudinal and transversal diffusion of charge carriers in disordered polar organic materials has been studied using Monte Carlo simulation. It was found that the simple Einstein relation is valid for the transversal diffusion coefficient, while neither the simple nor the modified Einstein relation is valid for the longitudinal diffusion coefficient. Effect of the field dependence of the transversal diffusion coefficient on the ultimate resolution of organic devices has been discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)