bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanostructure development in wet amorphous amylopectin as revealed by in situ X‐ray scattering methods
Authors: Bayer R. K. , Baltá‐Calleja F. J. 
Published: March 2006

AbstractCompletely amorphous, transparent bars of amylopectin were prepared by injection molding of pure native semicrystalline samples (Waxy Maize). The formation of a semicrystalline morphology was studied during annealing treatment at various temperatures in a wet atmosphere, using simultaneous WAXS and SAXS. Amylopectin samples crystallized during 20 days in a humid atmosphere at room temperature and subjected to a successive melting process were also studied by X‐ray scattering. Results indicate that individual molecules crystallize independently from each other, similar to the case of native amylopectin grains. During the first stages of crystallization, the changes in the SAXS pattern suggest that uncorrelated crystal blocks are formed, which may arrange to lamellae (if a secondary network of double‐helix net‐points is hydrothermally dissociated). At the beginning of the crystallization process, only few amylopectin molecules (about 10%) are incorporated into the nanostructure. A shell‐like structure of semicrystalline layers, comparable to that of a native grain, develops. When crystallization proceeds further, the initially thin shell layers thicken. This causes the amorphous interlayers to be subjected to inner tensions, leading to a decrease in the melt temperature. After a storage time of 20 days in a humid atmosphere, amylopectin reaches a crystallinity level of 54%, only slightly lower than that of the initial native grains. Upon heating the retrograded amylopectin, immediately before complete melting, the long‐period shows a value of 15 nm with a crystal thickness, derived from WAXS, of only 4 nm. Such a structure, which has not been reported before, is due to the relaxations of the inner tensions during melting, which lead to a disappearance of inserted interlamellar crystals. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3832‐3839, 2006
Miscibility and transesterification in ternary blends of poly(ethylene naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide)
Authors: Su Chean Cheng , Shih Chih Kuan 
Published: March 2006

AbstractMiscibility and morphology of poly(ethylene 2,6‐naphthalate)/poly(pentamethylene terephthalate)/poly(ether imide) (PEN/PPT/PEI) blends were studied by differential scanning calorimetry (DSC), optical microscopy (OM), proton nuclear magnetic resonance imaging (1H‐NMR), and wide‐angle X‐ray diffraction (WAXD). OM and DSC results from ternary blends revealed the immiscibility of PEN/PPT/PEI blends, but ternary blends of all compositions were phase‐homogeneous following heat treatment at 300°C for over 60 min. Annealing samples at 300°C yielded an amorphous blend with a clear and single Tg at the final state. Experimental data from 1H‐NMR revealed that PEN/PPT copolymers (ENPT) were formed by the so‐called transesterification. The effect of transesterification on glass transition and crystallization was discussed in detail. The sequence structures of the copolyester were identified by triad analysis, which showed that the mean sequence lengths became shorter and the randomness increased with heating time. The results reveal that a random copolymer improved the miscibility of the ternary blends, in which, the length of the homo segments in the polymer chain decreased and the crystal formation was disturbed because of the irregularity of the structure, as the exchange reaction proceeded. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3840–3849, 2006
Apparent active transport of MDMA is not mediated by P‐glycoprotein: a comparison with MDCK and Caco‐2 monolayers
Authors: Bertelsen Kirk M. , Greenblatt David J. , von Moltke Lisa L. 
Published: March 2006

AbstractAmphetamines and their methylenedioxy derivatives generically display similar behavioral, physiologic and toxic effects. Inconsistent pharmacokinetic and toxicity data for methylenedioxymethamphetamine (MDMA) may suggest that active drug transporters are interacting with these compounds, and thus altering drug absorption and tissue distribution.In vitromodels of CNS accumulation and intestinal drug transport were used to assess efflux transport of MDMA. Madin‐Darby kidney cell epithelial (MDCK) monolayers displayed a 4‐fold increase in accumulation in the basolateral to apical orientation relative to the apical to basolateral orientation, although no differential accumulation was noted between MDCK‐WT and MDCK‐MDR1 monolayers. Caco‐2 monolayers demonstrated an approximate 2‐fold increase in accumulation of MDMA. Exposure of various inhibitors of active drug transporters demonstrated mixed results; ritonavir, progesterone and indomethacin produced an approximately 50% reduction of MDMA transport, while verapamil, MK‐571 and probenecid had no effect. Based on these data, it is concluded that MDMA efflux is mediated via the activity of a transporter distinct from P‐glycoprotein. The possible inhibitory effects of amphetamines on rhodamine‐123 transport were also assessed. MDMA, methylenedioxyamphetamine, amphetamine and methamphetamine, at physiologically relevant concentrations, did not significantly alter the transport of rhodamine‐123 in Caco‐2 monolayers or the LS180 cell line, suggesting that these compounds do not alter the function of P‐glycoprotein. Copyright © 2006 John Wiley & Sons, Ltd.
A minimalistic 3D pharmacophore model for cyclopentapeptide CXCR4 antagonists
Authors: Våbenø Jon , Nikiforovich Gregory V. , Marshall Garland R. 
Published: March 2006

AbstractBecause of its involvement in HIV entry, the chemokine receptor CXCR4 is an attractive target for antiretroviral drugs. Despite the large number of CXCR4 inhibitors studied, the 3D pharmacophore for binding to CXCR4 remains elusive, mainly as a result of conformational flexibility inherent in the identified ligands. In the present study, an exhaustive systematic exploration of the conformational space for a series of analogs of FC131, a cyclopentapeptide CXCR4 antagonist, has been performed. By comparing the resulting low‐energy conformations using different sets of atoms, specific conformational features common only to the high/medium affinity compounds were identified. These features included the spatial arrangement of three pharmacophoric side chains as well as the orientation of a specific backbone amide bond. Together these features represent a minimalistic 3D pharmacophore model for binding of the cyclopentapeptide antagonists to CXCR4. The model enables rationalization of the experimental affinity data for this class of compounds as well as for the peptidomimetic KRH‐1636. © 2006 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 459–471, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
One‐pot synthesis in aqueous system for water‐soluble chitosan‐graft‐poly(ethylene glycol) methyl ether
Authors: Fangkangwanwong J. , Akashi Mitsuru , Kida Toshiyuki , Chirachanchai Suwabun 
Published: March 2006

AbstractChitosan is functionalized with poly(ethylene glycol) methyl ether (mPEG) at the amino and hydroxyl groups via a single step reaction in a homogeneous aqueous system. A chitosan aqueous solution obtained from the mixture of chitosan and hydroxybenzotriazole (HOBt) in water is a key factor in providing mild conditions to conjugate mPEG by using a carbodiimide conjugating agent. The reaction at ambient temperature for 24 h gives chitosan‐g‐mPEG with water solubility with mPEG content as high as 42%. This work demonstrates that a water‐soluble chitosan–HOBt complex is an effective system for the preparation of chitosan derivatives via the aqueous system without the use of acids or organic solvents. © 2006 Wiley Periodicals, Inc. Biopolymers 82:580–586, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Solid‐state IR–LD spectroscopic and theoretical analysis of glycine‐containing peptides and their hydrochlorides
Authors: Ivanova Bojidarka B. , Kolev Tsonko , Zareva Sonya Y. 
Published: March 2006

AbstractAs part of an investigation on the coordination ability of peptides, structural analyses of the solid di‐, tri, and tetrapeptides glycyl‐glycine (GG), glycyl‐glycyl‐glycine (GGG), glycyl‐glycyl‐glycyl‐glycine (GGGG), and their protonated hydrochlorides glycyl‐glycine·HCl (GGH), glycyl‐glycyl‐glycine·HCl (GGGH), and glycyl‐glycyl‐glycyl‐glycine·HCl (GGGGH) have been carried out. The quantum chemical calculations (Hartree‐Fock/6‐31++G**) and linear–dichroic infrared (IR–LD) spectroscopy predict a near to linear structure of the pure ligands, but the experimental IR–LD data are in accordance with a cross‐linked disposition of amide fragments in the protonated forms. © 2006 Wiley Periodicals, Inc. Biopolymers 82:587–596, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Facile preparation of biodegradable chitosan derivative having poly(butylene glycol adipate) side chains
Authors: Huang Meifang , Fang Yue'e 
Published: March 2006

AbstractVarious modes are being explored for the construction of functional materials from nanoparticles. Despite these efforts, the assembly of nanoparticles remains challenging with respect to the requirement of multiple component organization on varying dimensions and length scales. The graft copolymers of chitosan with poly(butylene glycol adipate) (PBGA) were prepared due to the esterification reaction between PBGA and 6‐O‐succinate‐N‐phthaloyl‐chitosan (PHCSSA) in the presence of toluene as a swelling agent. The graft copolymers are nanoparticles with the size of few hundred nanometers as observed from TEM. It is a potential method to combine chitosan with the hydrophobic synthetic polymers. The grafting reactions were conducted with various PBGA/PHCSSA feed ratios to obtain chitosan‐g‐PBGA copolymers with various PBGA contents. FT–IR, NMR, XRD, spectrofluorophotometer, and TEM were detected to characterize the copolymers. © 2006 Wiley Periodicals, Inc. Biopolymers 82:597–602, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Reduction in wound infection rates by wound surveillance with postdischarge follow-up and feedback
Authors: Wilson A P R , Hodgson B , Liu M , Plummer D , Taylor I , Roberts J , Jit M , Sherlaw-Johnson C 
Published: March 2006

Abstract

Background
Surgical wound surveillance with postdischarge follow-up is rarely done in the UK as it is seen as expensive. The aim of this study was to determine whether employing a dedicated team was effective and reduced costs.

Methods
Infection data were collected prospectively with postdischarge follow-up at 2–3 months, and fed back to surgeons. Wound infection was defined using both ASEPSIS wound scoring and criteria of the US Centers for Disease Control (CDC) definitions.

Results
Over 4 years, 15 548 patient episodes were included. Postdischarge surveillance data were available for 79·9 per cent of the 15 154 records of patients who survived. There was a significant reduction in the rate of wound infection between the first and fourth years by ASEPSIS and CDC definitions: odds ratio 0·77 (95 per cent confidence interval (c.i.) 0·64 to 0·92) and 0·69 (95 per cent c.i. 0·57 to 0·83), respectively. The proportion of infections fell significantly in orthopaedic, cardiac and thoracic surgery. The annual budget for wound surveillance was £91 600. Changes in infection rates contributed £347 491 to the reduction in cost among the patients surveyed.

Conclusion
Wound surveillance was associated with a reduction in rates of wound infection within 4 years. The cost reduction as a result of fewer infections exceeded the cost of surveillance after 2 years.
Leucocyte depletion improves renal function during reperfusion using an experimental isolated haemoperfused organ preservation system
Authors: Harper S , Hosgood S , Kay M , Nicholson M 
Published: March 2006

AbstractBackgroundLeucocytes have been implicated as mediators of renal ischaemia–reperfusion injury. This study aimed to demonstrate the effect of white cells in early renal reperfusion injury using an isolated haemoperfused porcine kidney model.MethodsAfter 2 h cold storage, porcine kidneys were perfused with normothermic autologous blood using an isolated organ preservation system. This was designed using cardiopulmonary bypass technology, and perfusion commenced with a circulating serum creatinine level of 1000 µmol/l. In group 1 (n = 6) a leucocyte filter was included in the circuit and in group 2 (n = 6) non-filtered blood was used.ResultsThe mean(s.d.) area under the curve for serum creatinine was lower in the leucocyte-depleted experiments (1286(214) versus 2627(418); P = 0·002). Leucocyte depletion also led to improved urine output (191(75) versus 70(32) ml/h; P = 0·002) and higher creatinine clearance (10·6(2·8) versus 1·9(1·0) ml/min; P = 0·002). Renal blood flow, oxygen consumption and acid–base homeostasis were all improved by perfusion with leucocyte-depleted blood, and histological tubular damage was ameliorated.ConclusionThese data show that the depletion of leucocytes from blood used to perfuse porcine kidneys improved postschaemic renal function, indicating that white cells play an important role in renal ischaemia–reperfusion injury.
Synthesis, Characterization, and Theoretical Study of Stable Isomers of C70(CF3)n (n = 2, 4, 6, 8, 10)
Authors: Dorozhkin Eugenii I. , Ignat'eva Daria V. , Tamm Nadezhda B. , Goryunkov Alexey A. , Khavrel Pavel A. , Ioffe Ilya N. , Popov Alexey A. , Kuvychko Igor V. , Streletskiy Alexey V. , Markov Vitaliy Y. , Spandl Johann , Strauss Steven H. , Boltalina Olga V. 
Published: March 2006

AbstractReaction of C70 with ten equivalents of silver(I) trifluoroacetate at 320–340 °C followed by fractional sublimation at 420–540 °C and HPLC processing led to the isolation of a single abundant isomer of C70(CF3)n for n = 2, 4, 6, and 10, and two abundant isomers of C70(CF3)8. These six compounds were characterized by using matrix‐assisted laser desorption ionization (MALDI) mass spectrometry, 2D‐COSY and/or 1D 19F NMR spectroscopy, and quantum‐chemical calculations at the density functional theory (DFT) level. Some were also characterized by Raman spectroscopy. The addition patterns for the isolated compounds were unambiguously found to be C1‐7,24‐C70(CF3)2, C1‐7,24,44,47‐C70(CF3)4, C2‐1,4,11,19,31,41‐C70(CF3)6, Cs‐1,4,11,19,31,41,51,64‐C70(CF3)8, C2‐1,4,11,19,31,41,51,60‐C70(CF3)8, and C1‐1,4,10,19,25,41,49,60,66,69‐C70(CF3)10 (IUPAC numbering). Except for the last compound, which is identical to the recently reported, crystallographically characterized C70(CF3)10 derivative prepared by a different synthetic route, these compounds have not previously been shown to have the indicated addition patterns. The largest relative yield under an optimized set of reaction conditions was for the Cs isomer of C70(CF3)8 (ca. 30 mol % of the sublimed mixture of products based on HPLC integration). The results demonstrate that thermally stable C70(CF3)n isomers tend to have their CF3 groups arranged on isolated para‐C6(CF3)2 hexagons and/or on a ribbon of edge‐sharing meta‐ and/or para‐C6(CF3)2 hexagons. For Cs‐ and C2‐C70(CF3)8 and for C2‐C70(CF3)6, the ribbons straddle the C70 equatorial belt; for C1‐C70(CF3)4, the para–meta–para ribbon includes three polar hexagons; for C1‐7,24‐C70(CF3)2, the para‐C6(CF3)2 hexagon includes one of the carbon atoms on a C70 polar pentagon. The 10.3–16.2 Hz 7JF,F NMR coupling constants for the end‐of‐ribbon CF3 groups, which are always para to their nearest‐neighbor CF3 group, are consistent with through‐space Fermi‐contact interactions between the fluorine atoms of proximate, rapidly rotating CF3 groups.
Evidence that the canonical Wnt signalling pathway regulates deer antler regeneration
Authors: Mount J. G. , Muzylak M. , Allen S. , Althnaian T. , McGonnell I. M. , Price J. S. 
Published: March 2006

AbstractWnt signalling regulates many developmental processes, including the fate specification, polarity, migration, and proliferation of cranial neural crest. The canonical Wnt pathway has also been shown to play an important role in bone physiology and there is evidence for its recapitulation during organ regeneration in lower vertebrates. This study explores the role of the Wnt signalling pathway in deer antlers, frontal bone appendages that are the only mammalian organs capable of regeneration. Immunocytochemistry was used to map the distribution of the activated form of β‐catenin (aβCAT). A low level of aβCAT staining was detected in chondrocytes and in osteoblasts at sites of endochondral bone formation. However, aβCAT was localised in cellular periosteum and in osteoblasts in intramembranous bone, where it co‐localised with osteocalcin. The most intense aβCAT staining was in dividing undifferentiated cells in the mesenchymal growth zone. Antler progenitor cells (APCs) were cultured from this region and when the canonical Wnt pathway was inhibited at the level of Lef/TCF by epigallocatechin gallate (EGCG), the cell number decreased. TUNEL staining revealed that this was as a result of increased apoptosis. Activation of the pathway by lithium chloride (LiCl) had no effect on cell number but inhibited alkaline phosphate activity (ALP), a marker of APC differentiation, whereas EGCG increased ALP activity. This study demonstrates that β‐catenin plays an important role in the regulation of antler progenitor cell survival and cell fate. It also provides evidence that β‐catenin's function in regulating bone formation by osteoblasts may be site‐specific. Developmental Dynamics 235:1390–1399, 2006. © 2006 Wiley‐Liss, Inc.
Opposite roles of neutrophils and macrophages in the pathogenesis of acetaminophen‐induced acute liver injury
Authors: Ishida Yuko , Kondo Toshikazu , Kimura Akihiko , Tsuneyama Kouichi , Takayasu Tatsunori , Mukaida Naofumi 
Published: March 2006

AbstractNeutrophils and macrophages infiltrate after acetaminophen (APAP)‐induced liver injury starts to develop. However, their precise roles still remain elusive. In untreated and control IgG‐treated wild‐type (WT) mice, intraperitoneal APAP administration (750 mg/kg) caused liver injury including centrilobular hepatic necrosis and infiltration of neutrophils and macrophages, with about 50% mortality within 48 h after the injection. APAP injection markedly augmented intrahepatic gene expression of inducible nitric oxide synthase (iNOS) and heme oxygenase (HO)‐1. Moreover, neutrophils expressed iNOS, which is presumed to be an aggravating molecule for APAP‐induced liver injury, while HO‐1 was mainly expressed by macrophages. All anti‐granulocyte antibody‐treated neutropenic WT and most CXC chemokine receptor 2 (CXCR2)‐deficient mice survived the same dose of APAP, with reduced neutrophil infiltration and iNOS expression, indicating the pathogenic roles of neutrophils in APAP‐induced liver injury. However, APAP caused more exaggerated liver injury in CXCR2‐deficient mice with reduced macrophage infiltration and HO‐1 gene expression, compared with neutropenic WT mice. An HO‐1 inhibitor, tin‐protoporphyrin‐IX, significantly increased APAP‐induced mortality, implicating HO‐1 as a protective molecule for APAP‐induced liver injury. Thus, CXCR2 may regulate the infiltration of both iNOS‐expressing neutrophils and HO‐1‐expressing macrophages, and the balance between these two molecules may determine the outcome of APAP‐induced liver injury.
A role for the Hsp90 molecular chaperone family in antigen presentation to T lymphocytes via major histocompatibility complex class II molecules
Authors: Rajagopal Deepa , Bal Vineeta , Mayor Satyajit , George Anna , Rath Satyajit 
Published: March 2006

AbstractThe heat shock protein (HSP) Hsp90 is known to chaperone cytosolic peptides for MHC class I (MHCI)‐restricted antigen presentation to T lymphocytes. We now demonstrate a role for Hsp90 activity in presentation of antigens on MHCII. Treatment of mouse antigen‐presenting cells (APC) with the pharmacological Hsp90 inhibitor, geldanamycin, inhibited MHCII‐mediated presentation of endocytosed and cytosolic proteins as well as synthetic peptides to specific T cells. Ectopic expression of human Hsp90 in APC enhanced MHCII‐mediated antigen presentation. Further, pharmacological Hsp90 inhibition reduced, while retroviral Hsp90 overexpression enhanced, the levels of stable compact MHCII heterodimers correlating with the antigen presentation phenotype. Pharmacological inhibition of Hsp90 activity in IFN‐γ‐treated APC resulted in severe abrogation of MHCII‐restricted presentation of cytosolic antigen, but only partially inhibited exogenous antigen presentation. Our data suggest a major role for Hsp90 activity in MHCII‐mediated antigen presentation pathways, and implicate IFN‐γ‐inducible Hsp90‐independent mechanisms.
Immunoadsorption against two distinct epitopes on human type XVII collagen abolishes dermal‐epidermal separation induced in vitro by autoantibodies from pemphigoid gestationis patients
Authors: Herrero‐González Josep E. , Brauns Olaf , Egner Ralf , Rönspeck Wolfgang , Mascaró José M. , Jonkman Marcel F. , Zillikens Detlef , Sitaru Cassian 
Published: March 2006

AbstractPemphigoid gestationis (PG) is a subepidermal autoimmune blistering disease characterized by self‐reactive T and B cells specific for the transmembrane hemidesmosomal protein type XVII collagen/BP180. Major T and B cell epitopes are located within the immunodominant 16th non‐collagenous domain A (NC16A) of type XVII collagen. The aim of the present study was to map the pathogenically relevant epitopes targeted by blister‐inducing patients’ autoantibodies. For this purpose, we used an in vitro model of autoantibody‐induced leukocyte‐dependent dermal‐epidermal separation. Pre‐adsorption against a recombinant form of the NC16A region abolished the blister‐inducing potential of autoantibodies from all PG patients. Using overlapping synthetic peptides, we demonstrated that PG autoantibodies bind to two defined epitopes within the NC16A region (aa 500–514 and aa 511–523). Importantly, pre‐adsorption using an affinity matrix containing these epitopes completely abolished dermal‐epidermal separation induced by PG autoantibodies. This study identifies the epitopes relevant for blister induction in PG and should facilitate the development of an antigen‐specific immunoadsorption therapy for this disease.