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Christensen PA, Lee NE, Thrall MJ, Powell SZ, Chevez-Barrios P, Long SW. RecutClub.com: An Open Source, Whole Slide Image-based Pathology Education System. J Pathol Inform 2017; 8:10. [PMID: 28382224 PMCID: PMC5364738 DOI: 10.4103/jpi.jpi_72_16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/18/2017] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Our institution's pathology unknown conferences provide educational cases for our residents. However, the cases have not been previously available digitally, have not been collated for postconference review, and were not accessible to a wider audience. Our objective was to create an inexpensive whole slide image (WSI) education suite to address these limitations and improve the education of pathology trainees. MATERIALS AND METHODS We surveyed residents regarding their preference between four unique WSI systems. We then scanned weekly unknown conference cases and study set cases and uploaded them to our custom built WSI viewer located at RecutClub.com. We measured site utilization and conference participation. RESULTS Residents preferred our OpenLayers WSI implementation to Ventana Virtuoso, Google Maps API, and OpenSlide. Over 16 months, we uploaded 1366 cases from 77 conferences and ten study sets, occupying 793.5 GB of cloud storage. Based on resident evaluations, the interface was easy to use and demonstrated minimal latency. Residents are able to review cases from home and from their mobile devices. Worldwide, 955 unique IP addresses from 52 countries have viewed cases in our site. CONCLUSIONS We implemented a low-cost, publicly available repository of WSI slides for resident education. Our trainees are very satisfied with the freedom to preview either the glass slides or WSI and review the WSI postconference. Both local users and worldwide users actively and repeatedly view cases in our study set.
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Christensen PA, Attidekou PS, Egdell RG, Maneelok S, Manning DAC. An in situ FTIR spectroscopic and thermogravimetric analysis study of the dehydration and dihydroxylation of SnO2: the contribution of the (100), (110) and (111) facets. Phys Chem Chem Phys 2016; 18:22990-8. [PMID: 27488937 DOI: 10.1039/c6cp03358j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanoparticulate SnO2 produced by a hydrothermal method was characterised by BET, XRD, TGA-MS and in situ variable temperature diffuse reflectance infra red spectroscopy (DRIFTS) to determine the surface behaviour of water. For the (100) facets, hydrogen bonding does not occur, and water adsorption is less strong than for the (111) and (110) facets where hydrogen bonding does occur. Reversible uptake of oxygen was observed. These findings have implications for other surface-gas reactions in which Ni and Sb co-doped SnO2 (NATO) anodes are used for ozone generation. BET showed the relatively high surface area and nanometer scale of the SnO2 particles, whilst XRD confirmed the nano dimension of the crystallites and showed only the cassiterite phase. TGA analysis indicated four temperature regions over which mass loss was observed. These and the in situ DRIFTS studies revealed the existence of various forms of water associated with specific crystal facets of the SnO2, as well as the existence of isolated O-H groups and adsorbed oxygen species. Electronic absorptions were also observed and the data rationalised in terms of the existence of both free electron absorptions, and absorptions from oxygen vacancy states. The role of adsorbed molecular oxygen in electrochemical ozone generation at Ni and Sb co-doped SnO2 (NATO) anodes was strongly suggested by this work.
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Jespersen JG, Mikkelsen UR, Nedergaard A, Thorlund JB, Schjerling P, Suetta C, Christensen PA, Aagaard P. Alterations in molecular muscle mass regulators after 8 days immobilizing Special Forces mission. Scand J Med Sci Sports 2014; 25:175-83. [PMID: 24422600 DOI: 10.1111/sms.12170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2013] [Indexed: 01/01/2023]
Abstract
In military operations, declined physical capacity can endanger the life of soldiers. During special support and reconnaissance (SSR) missions, Special Forces soldiers sustain 1-2 weeks full-body horizontal immobilization, which impairs muscle strength and performance. Adequate muscle mass and strength are necessary in combat or evacuation situations, which prompt for improved understanding of muscle mass modulation during SSR missions. To explore the molecular regulation of myofiber size during a simulated SSR operation, nine male Special Forces soldiers were biopsied in m. vastus lateralis pre and post 8 days immobilizing restricted prone position. After immobilization, total mammalian target of rapamycin protein was reduced by 42% (P < 0.05), whereas total and phosphorylated protein levels of Akt, ribosomal protein S6k, 4E-BP1, and glycogen synthase kinase3β were unchanged. Messenger RNA (mRNA) levels of the atrogenes forkhead box O3 (FoxO3), atrogin1, and muscle ring finger protein1 (MuRF1) increased by 36%, 53%, and 71% (P < 0.01), MuRF1 protein by 51% (P = 0.05), whereas FoxO1 and peroxisome proliferator-activated receptor γ coactivator-1 β mRNAs decreased by 29% and 40% (P < 0.01). In conclusion, occupational immobilization in Special Forces soldiers led to modulations in molecular muscle mass regulators during 8 days prone SSR mission, which likely contribute to muscle loss observed in such operations. The present data expand our knowledge of human muscle mass regulation during short-term immobilization.
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Liu X, Christensen PA, Kelly SM, Rocher V, Scott K. Al2O3 Disk Supported Si3N4 Hydrogen Purification Membrane for Low Temperature Polymer Electrolyte Membrane Fuel Cells. MEMBRANES 2013; 3:406-14. [PMID: 24957065 PMCID: PMC4021953 DOI: 10.3390/membranes3040406] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/02/2013] [Indexed: 11/24/2022]
Abstract
Reformate gas, a commonly employed fuel for polymer electrolyte membrane fuel cells (PEMFCs), contains carbon monoxide, which poisons Pt-containing anodes in such devices. A novel, low-cost mesoporous Si3N4 selective gas separation material was tested as a hydrogen clean-up membrane to remove CO from simulated feed gas to single-cell PEMFC, employing Nafion as the polymer electrolyte membrane. Polarization and power density measurements and gas chromatography showed a clear effect of separating the CO from the gas mixture; the performance and durability of the fuel cell was thereby significantly improved.
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Freitas RG, Pereira EC, Christensen PA. The selective oxidation of ethanol to CO2 at Ptpc/Ir/Pt metallic multilayer nanostructured electrodes. Electrochem commun 2011. [DOI: 10.1016/j.elecom.2011.07.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Yang R, Christensen PA, Egerton TA, White JR, Maltby A. Spectroscopic studies of photodegradation of polyethylene films containing TiO2 nanoparticles. J Appl Polym Sci 2010. [DOI: 10.1002/app.31669] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fernando SS, Christensen PA, Egerton TA, White JR. Humidity dependence of carbon dioxide generation during photodegradation of biaxially oriented polypropylene in oxygen. Polym Degrad Stab 2009. [DOI: 10.1016/j.polymdegradstab.2008.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Christensen PA, Danielczyk A, Ravn P, Stahn R, Karsten U, Goletz S. A Monoclonal Antibody to Lewis Y/Lewis b Revealing Mimicry of the Histone H1 to Carbohydrate Structures. Scand J Immunol 2007; 65:362-7. [PMID: 17386027 DOI: 10.1111/j.1365-3083.2007.01913.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Antibodies to either peptide or carbohydrate tumour antigens are established tools for diagnostics and therapy. We here describe an antibody (A70-A/A9) recognizing a carbohydrate epitope common to the tumour-associated Lewis Y and Lewis b antigens (Fucalpha1-2Galbeta1-4/3[Fucalpha1-3/4]GlcNAcbeta-). Its specificity was established without doubt with a panel of 86 synthetic mono- and oligosaccharidic structures. This antibody was found to cross-react with the nuclear protein histone H1. Binding to H1 was specific, periodate-insensitive (non-carbohydrate) and saturable. Histone H1 was able to inhibit Lewis Y binding very effectively in a concentration-dependent manner. We conclude that it represents an example of natural peptide mimicry of a carbohydrate epitope. It may explain the observed occurrence of 'anti-histone autoantibodies' in cancer patients.
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Shao ZG, Zhu F, Lin WF, Christensen PA, Zhang H. PtRu/Ti anodes with varying Pt ? Ru ratio prepared by electrodeposition for the direct methanol fuel cell. Phys Chem Chem Phys 2006; 8:2720-6. [PMID: 16763704 DOI: 10.1039/b604939g] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PtRu/Ti anodes with varying Pt ratio Ru ratio were prepared by electrodeposition of a thin PtRu catalyst layer onto Ti mesh for a direct methanol fuel cell (DMFC). The morphology and structure of the catalyst layers were analyzed by SEM, EDX and XRD. The catalyst coating layer shows an alloy character. The relative activities of the PtRu/Ti electrodes were assessed and compared in half cell and single DMFC experiments. The results show that these electrodes are very active for the methanol oxidation and that the optimum Ru surface coverage was ca. 9 at.% for DMFC operating at 20 degrees C and 11 at.% at 60 degrees C. The PtRu/Ti anode shows a performance comparable to that of the conventional carbon-based anode in a DMFC operating with 0.25 M or 0.5 M methanol solution and atmosphere oxygen gas at 90 degrees C.
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Egerton TA, Kosa SAM, Christensen PA. Photoelectrocatalytic disinfection of E. coli suspensions by iron doped TiO2. Phys Chem Chem Phys 2006; 8:398-406. [PMID: 16482283 DOI: 10.1039/b507516e] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoelectrocatalytic disinfection of E. coli by an iron doped TiO(2) sol-gel electrode is shown to be more efficient than disinfection by the corresponding undoped electrode. Thus, the improvements in photocatalytic efficiency associated with selective doping have been combined with the electric field enhancement associated with the application of a small positive potential to a UV irradiated titanium dioxide electrode. The optimum disinfection rate corresponds to the replacement of approximately 0.1% of the Ti atoms by Fe. The enhanced disinfection associated with iron doping is surprising because iron doping decreases the photocurrent, and photocurrent is generally taken to be a good indicator of photoelectrocatalytic efficiency. As the level of iron is increased, the character of the current-voltage curve changes and the enhancement of photocurrent associated with methanol addition decreases. This suggests that iron reduces the surface recombination which in the absence of iron is reduced by methanol. Therefore the enhanced photocatalysis is interpreted as due to iron reducing surface recombination, by trapping electrons. It is proposed that at low iron levels the photo-generated electrons are trapped at surface Fe(III) centres and that consequently, because the electron-hole recombination rate is reduced, the number of holes available for hydroxyl radical formation is increased. It is also proposed that at higher iron levels, the disinfection rate falls because electron hole recombination at iron centres in the lattice reduces the number of holes which reach the surface. Our conclusion that the optimum electrode performance is a balance between surface and bulk effects is consistent with the proposal, of earlier authors for photocatalytic reactions, that the optimum dopant level depends on the TiO(2).
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Christensen PA, Egerton TA, Lin WF, Meynet P, Shao ZG, Wright NG. A novel electrochemical device for the disinfection of fluids by OH radicals. Chem Commun (Camb) 2006:4022-3. [PMID: 17003886 DOI: 10.1039/b608329n] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper describes a novel, composite device, based not on optical excitation but on the transfer of holes from Si to the TiO(2)/air or TiO(2)/water interface, for the disinfection and detoxification of fluid streams.
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Christensen PA, Jin JM, Lin WF, Hamnett A. Identification of CO Adsorbed at Ru and Pt Sites on a Polycrystalline Pt/Ru Electrode and the Observation of Their Oxidation and Free Interchange under Open Circuit Conditions. J Phys Chem B 2004. [DOI: 10.1021/jp037520b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cheng H, Scott K, Christensen PA. Electrochemical hydrodehalogenation of 2,4-dibromophenolin paraffin oil using a solid polymer electrolyte reactor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:638-642. [PMID: 14750742 DOI: 10.1021/es034775u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A new technology for remediation of halogenated organics-oil systems, which can cause serious environmental problems, has been demonstrated using the electrochemical hydrodehalogenation of 2,4-dibromophenol (DBP) in paraffin oil in a solid polymer electrolyte reactor. The reactor has been evaluated in terms of cathode materials and structure and the ratio of the cathode surface area to the solution volume. A cathode of titanium minimesh with a palladium electrocatalyst produced by electrodeposition was particularly effective. Current efficiencies of up to 85% and percentage of DBP removal of up to 62%, space-time yields of up to 7.6 kg DBP m(-3) h(-1), and energy consumption as low as 1.6 kW h (kg of DBP)(-1) were achieved. The reactor showed stable operation for periods of up to 170 h. The results demonstrated that electroreduction could be an alternative technology to electrooxidation forthe treatment of wastes and toxic halogenated compounds, making the process simpler in comparison to electrooxidation.
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Chetty R, Christensen PA, Golding BT. In situ FTIR studies on the electrochemical reduction of halogenated phenols. Chem Commun (Camb) 2003:984-5. [PMID: 12744331 DOI: 10.1039/b212647h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrochemical reduction of a variety of mono- and di-chloro- and bromo- phenols at a palladised titanium electrode afforded phenolate in all cases according to in situ FTIR studies, with the same intermediate species being observed in some cases.
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Lin WF, Christensen PA. In situ FTIR studies on the effect of temperature on the electro-oxidation of small organic molecules at the Ru(0001) electrode. Faraday Discuss 2002:267-84; discussion 331-64. [PMID: 12227573 DOI: 10.1039/b110956c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The adsorption and electro-oxidation of formaldehyde, formic acid and methanol at the Ru(0001) electrode in perchloric acid solution have been studied as a function of temperature, potential and time using in situ FTIR spectroscopy, and the results interpreted in terms of the surface chemistry of the Ru(000 1) electrode and compared to those obtained during our previous studies on the adsorption of CO under the same conditions. It was found that no dissociative adsorption or electro-oxidation of methanol takes place at Ru(0001) at potentials < 900 mV vs. Ag/AgCl, and at all three temperatures employed, 10, 25 and 50 degrees C. However, both formaldehyde and formic acid did undergo dissociative adsorption, even at -200 mV, to form linear (CO(L)) and 3-fold-hollow (COH) binding CO adsorbates. In contrast to the adsorption of CO, it was found that increasing the temperature to 50 degrees C markedly increased the amount of CO adsorbates formed on the Ru(0001) surface from the adsorption of both formaldehyde and formic acid. On increasing the potential, the electro-oxidation of the CO adsorbates to CO2 took place via reaction with the active (1 x 1)-O oxide. Formic acid was detected as a partial oxidation product during formaldehyde electro-oxidation. At all three temperatures employed, it was found that adsorbed CO species were formed from the adsorption of both formic acid and formaldehyde, and were oxidised to CO2 faster than was observed in the experiments involving CO adsorbed from CO(g), suggesting a higher mobility of the CO adsorbates formed from the adsorption of the HCOOH and HCHO. At potentials > 1000 mV, both the oxidation of formic acid to CO2 and the oxidation of formaldehyde to both CO2 and formic acid were significantly increased, and the oxidation of methanol to CO2 and methyl formate was observed, all of which were attributed to the formation of an active RuO2 phase on the Ru(0001) surface.
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Curtis TP, Walker G, Dowling BM, Christensen PA. Fate of Cryptosporidium oocysts in an immobilised titanium dioxide reactor with electric field enhancement. WATER RESEARCH 2002; 36:2410-2413. [PMID: 12108733 DOI: 10.1016/s0043-1354(01)00434-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have undertaken simple proof of principle experiments to find out if electric field enhanced photo-oxidation using immobilised titanium dioxide will damage Cryptosporidium oocysts. Using a simple Petri dish reactor and two forms of immobilised titanium catalyst (sol-gel and thermal-film) we have tested the ability of this technology to affect Cryptosporidium oocysts permeability assessed by propidium iodide exclusion. Test and control reactor runs were significantly different (P = 0.007). The thermal-film reactor had the greatest effect (approximately 27% of the seed) and was statistically distinguishable from the sol-gel reactor and the controls. The sol-gel reactor showed an increase in oocyst permeability, but was not statistically distinguishable from one of the controls. The enhanced performance of the thermal film reactor is attributed to the superior conversion of photochemical holes to hydroxyl radicals at the surface of this catalyst.
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Jones CL, Higgins SJ, Christensen PA. Some in situ reflectance Fourier transform infrared studies of electrochemically prepared polybenzo[c]thiophene and poly-5-fluorobenzo[c]thiophene filmsElectronic supplementary information (ESI) available: schematic representation of the energy levels of polybenzothiophenes, CVs and FTIR spectra. See http://www.rsc.org/suppdata/jm/b1/b108054g/. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b108054g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vilas-Boas M, Freire C, de Castro B, Christensen PA, Hillman AR. Spectroelectrochemical characterisation of poly[Ni(saltMe)]-modified electrodes. Chemistry 2001; 7:139-50. [PMID: 11205005 DOI: 10.1002/1521-3765(20010105)7:1<139::aid-chem139>3.0.co;2-q] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electrogenerated polymers based on the nickel(II) complex 2,3-dimethyl-N,N'-bis(salicylidene)butane-2,3-diaminatonickel(II), poly[Ni(saltMe)], were characterised by in situ FTIR and UV/Vis spectroscopy and ex-situ EPR spectroscopy in order to gain insights into film structure, electronic states and charge conduction. The role of the nickel ions during film oxidation was probed by using EPR to study naturally abundant Ni and 61Ni-enriched polymers. The data from all the spectroscopic techniques are consistent, and clearly indicate that polymerisation and redox switching are associated with oxidative ligand based processes; coulometry suggests that one positive charge was delocalised through each monomer unit. EPR provided evidence for the non-direct involvement of the metal in polymer oxidation: the polymer is best described as a polyphenylene-type compound (conducting polymer), rather than an aggregation of nickel complexes (redox polymer), and the main charge carriers are identified as polarons. An explanation for the high electrochemical stability and conductivity of poly[Ni(saltMe)] with respect to that of poly[Ni(salen)] is proposed. based on stereochemical repulsion between monomeric units; this can impose a less compact supramolecular structure on polymers with bulkier substituents.
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Higgins SJ, Pounds TJ, Christensen PA. Syntheses and electro(co)polymerization of novel thiophene- and 2,2′:5′,2″-terthiophene-functionalized metal–tetraazamacrocycle complexes, and electrochemical and spectroelectrochemical characterization of the resulting polythiophenes. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b103284b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Andersen OM, Christensen PA, Christensen LL, Jacobsen C, Moestrup SK, Etzerodt M, Thogersen HC. Specific binding of alpha-macroglobulin to complement-type repeat CR4 of the low-density lipoprotein receptor-related protein. Biochemistry 2000; 39:10627-33. [PMID: 10978145 DOI: 10.1021/bi000498h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The low-density lipoprotein receptor-related protein (LRP) is a large surface receptor that mediates binding and internalization of a large number of structurally and functionally unrelated ligands. The ligand binding sites are located in clusters of complement-type repeats (CR), where the general absence of mutual binding competition suggests that different ligands map to distinct sites. Binding of alpha(2)-macroglobulin-protease complexes to the LRP is mediated by the receptor binding domain (RBD) of alpha(2)-macroglobulin (alpha(2)M). To determine the major binding epitope(s) in the LRP, we generated a complete set of tandem CR proteins spanning the second cluster of CR domains, and identified a binding site for alpha(2)M in the N-terminal part of the cluster comprising CR3-CR6, using ligand blotting and surface plasmon resonance (SPR) analysis. The specific site involved in alpha(2)M recognition resides in the fourth CR domain, CR4, whereas another site is identified in CR5. An acidic epitope in CR4 is identified as important for binding alpha(2)M by mutagenesis and SPR analysis. The formation of the complex between the rat alpha(1)-macroglobulin RBD and CR domain pairs is characterized by analytical size-exclusion chromatography, which demonstrates a sufficiently strong interaction between the alpha(1)M RBD and CR34 or CR45 for the isolation of a complex.
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Andersen OM, Christensen LL, Christensen PA, Sørensen ES, Jacobsen C, Moestrup SK, Etzerodt M, Thogersen HC. Identification of the minimal functional unit in the low density lipoprotein receptor-related protein for binding the receptor-associated protein (RAP). A conserved acidic residue in the complement-type repeats is important for recognition of RAP. J Biol Chem 2000; 275:21017-24. [PMID: 10747921 DOI: 10.1074/jbc.m000507200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The low density lipoprotein receptor-related protein (LRP), a member of the low density lipoprotein receptor family, mediates the internalization of a diverse set of ligands. The ligand binding sites are located in different regions of clusters consisting of approximately 40 residues, cysteine-rich complement-type repeats (CRs). The 39-40-kDa receptor-associated protein, a folding chaperone/escort protein required for efficient transport of functional LRP to the cell surface, is an antagonist of all identified ligands. To analyze the multisite inhibition by RAP in ligand binding of LRP, we have used an Escherichia coli expression system to produce fragments of the entire second ligand binding cluster of LRP (CR3-10). By ligand affinity chromatography and surface plasmon resonance analysis, we show that RAP binds to all two-repeat modules except CR910. CR10 differs from other repeats in cluster II by not containing a surface-exposed conserved acidic residue between Cys(IV) and Cys(V). By site-directed mutagenesis and ligand competition analysis, we provide evidence for a crucial importance of this conserved residue for RAP binding. We provide experimental evidence showing that two adjacent complement-type repeats, both containing a conserved acidic residue, represent a minimal unit required for efficient binding to RAP.
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Christensen PA, Tvedegaard E, Strandgaard S, Thomsen BS. Behçet's syndrome presenting with peripheral arterial aneurysms. Scand J Rheumatol 1997; 26:386-8. [PMID: 9385353 DOI: 10.3109/03009749709065705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A case of Behçet's syndrome is described presenting with several peripheral arterial aneurysms. The diagnostic criteria are discussed and the need for increased vigilance of this disease is stressed due to an increasing number of immigrants.
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Vilas-Boas M, Freire C, de Castro B, Christensen PA, Hillman AR. New Insights into the Structure and Properties of Electroactive Polymer Films Derived from [Ni(salen)]. Inorg Chem 1997. [DOI: 10.1021/ic970467j] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Doherty AP, Christensen PA, Scott K. Inter-micellar interaction under hydrodynamic conditions. Chem Commun (Camb) 1996. [DOI: 10.1039/cc9960001531] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Christensen PA, Rotne M, Vedelsdal R, Jensen RH, Jacobsen K, Husted C. Electroacupuncture in anaesthesia for hysterectomy. Br J Anaesth 1993; 71:835-8. [PMID: 8280549 DOI: 10.1093/bja/71.6.835] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We have studied the effects of electroacupuncture at classical acupuncture points, applied before and during surgery in patients undergoing hysterectomy, on postoperative pain and metabolic stress responses in a prospective, randomized and patient-blinded manner. Fifty otherwise healthy women were allocated randomly to receive or not receive electroacupuncture. Electroacupuncture was begun 20 min before skin incision and continued to the end of surgery. All patients received similar general anaesthesia and all received patient-controlled analgesia (PCA) after operation. Postoperative pain in the two groups was evaluated by recording analgesic requirements by PCA and by pain-rating performed by patients and nursing staff. There were no significant differences between the two groups in postoperative analgesic requirements, pain-rating or metabolic stress responses.
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