1
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Patel M, Forte N, Bishop CR, Porter MJ, Dagwell M, Karu K, Chudasama V, Baker JR. The Nitrile Bis-Thiol Bioconjugation Reaction. J Am Chem Soc 2024; 146:274-280. [PMID: 38124442 PMCID: PMC10786040 DOI: 10.1021/jacs.3c08762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
Electron-poor aryl nitriles are promising reagents for bioconjugation due to their high electrophilicity and selectivity for reaction with thiols, albeit generally in a reversible manner. A transient species has previously been observed in such reactions, involving the addition of two thiols to the nitrile functional group, forming a tetrahedral amino dithioacetal (ADTA). In this work, the reaction of heteroaryl nitriles with bis-thiols is explored in an attempt to generate stable ADTAs, which could facilitate new bioconjugation protocols. By use of a 1,2-dithiol, or the incorporation of an electrophilic trap into the aryl nitrile design, the formation of stable products is achieved. The resultant "nitrile bis-thiol" (NBT) reaction is then explored in the context of protein modification, specifically to carry out antibody conjugation. By addition of these nitriles to the reduced disulfide bond of an antibody fragment, it is shown that, depending on the reagent design, cysteine-to-lysine transfer or disulfide bridged NBT products can be generated. Both represent site-selective conjugates and are shown to be stable when challenged with glutathione under physiological conditions and upon incubation in serum. Furthermore, the NBT reaction is tested in the more challenging context of a full antibody, and all four disulfide bonds are effectively modified by these new one-carbon bridging reagents. Overall, this reaction of heteroaryl-nitriles with bis-thiols is shown to be highly efficient and versatile, of tunable reversibility, and offers enticing prospects as a new addition to the toolbox of biocompatible "click"-type reactions.
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Affiliation(s)
- Mikesh Patel
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - Nafsika Forte
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - Charlie R. Bishop
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - Michael J. Porter
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - Matthew Dagwell
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - Kersti Karu
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - Vijay Chudasama
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
| | - James R. Baker
- Department
of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, U.K.
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2
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Rochet LNC, Bahou C, Wojciechowski JP, Koutsopetras I, Britton P, Spears RJ, Thanasi IA, Shao B, Zhong L, Bučar DK, Aliev AE, Porter MJ, Stevens MM, Baker JR, Chudasama V. Use of pyridazinediones for tuneable and reversible covalent cysteine modification applied to peptides, proteins and hydrogels. Chem Sci 2023; 14:13743-13754. [PMID: 38075666 PMCID: PMC10699563 DOI: 10.1039/d3sc04976k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 10/27/2023] [Indexed: 05/02/2024] Open
Abstract
Reversible cysteine modification has been found to be a useful tool for a plethora of applications such as selective enzymatic inhibition, activity-based protein profiling and/or cargo release from a protein or a material. However, only a limited number of reagents display reliable dynamic/reversible thiol modification and, in most cases, many of these reagents suffer from issues of stability, a lack of modularity and/or poor rate tunability. In this work, we demonstrate the potential of pyridazinediones as novel reversible and tuneable covalent cysteine modifiers. We show that the electrophilicity of pyridazinediones correlates to the rates of the Michael addition and retro-Michael deconjugation reactions, demonstrating that pyridazinediones provide an enticing platform for readily tuneable and reversible thiol addition/release. We explore the regioselectivity of the novel reaction and unveil the reason for the fundamental increased reactivity of aryl bearing pyridazinediones by using DFT calculations and corroborating findings with SCXRD. We also applied this fundamental discovery to making more rapid disulfide rebridging agents in related work. We finally provide the groundwork for potential applications in various areas with exemplification using readily functionalised "clickable" pyridazinediones on clinically relevant cysteine and disulfide conjugated proteins, as well as on a hydrogel material.
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Affiliation(s)
- Léa N C Rochet
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Calise Bahou
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Jonathan P Wojciechowski
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London London SW7 2AZ UK
| | - Ilias Koutsopetras
- Bio-Functional Chemistry (UMR 7199), Institut du Médicament de Strasbourg, University of Strasbourg 74 Route du Rhin 67400 Illkirch-Graffenstaden France
| | - Phyllida Britton
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Richard J Spears
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Ioanna A Thanasi
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Baihao Shao
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London London SW7 2AZ UK
| | - Lisha Zhong
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London London SW7 2AZ UK
| | - Dejan-Krešimir Bučar
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Abil E Aliev
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Michael J Porter
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering, Institute of Biomedical Engineering, Imperial College London London SW7 2AZ UK
| | - James R Baker
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
| | - Vijay Chudasama
- Department of Chemistry, University College London 20 Gordon Street London WC1H 0AJ UK
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3
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Wilson I, Padamati SK, Bobitan AD, Porter MJ, Holt KB. Room-Temperature One-Pot Synthesis of pH-Responsive Pyridine-Functionalized Carbon Surfaces. ACS Omega 2023; 8:10796-10805. [PMID: 37008109 PMCID: PMC10061597 DOI: 10.1021/acsomega.2c06847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
Carbon surfaces (glassy carbon, graphite, and boron-doped diamond) were functionalized with layers composed of linked pyridinium and pyridine moieties using simple electrochemical reduction of trifluoroacetylpyridinium. The pyridinium species was generated in situ in solution by the reaction of trifluoroacetic anhydride and pyridine precursors and underwent electrochemical reduction at -1.97 V vs Fc/Fc+, as determined by cyclic voltammetry. The pyridine/pyridinium films were electrodeposited at room temperature, on a timescale of minutes, and were characterized using X-ray photoelectron spectroscopy. The as-prepared films have a net positive charge in aqueous solution at pH 9 and below due to the pyridinium content, confirmed by the electrochemical response of differently charged redox molecules at the functionalized surfaces. The positive charge can be enhanced further through protonation of the neutral pyridine component by controlling the solution pH. Moreover, the nitrogen-acetyl bond can be cleaved through base treatment to purposefully increase the neutral pyridine proportion of the film. This results in a surface that can be "switched" from functionally near neutral to a positive charge by treatment in basic and acidic solutions, respectively, through manipulation of the protonation state of the pyridine. The functionalization process demonstrated here is readily achievable at a fast timescale at room temperature and hence can allow for rapid screening of surface properties. Such functionalized surfaces present a means to test in isolation the specific catalytic performance of pyridinic groups toward key processes such as oxygen and CO2 reduction.
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4
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Abstract
![]()
Sugars
are abundant in waste biomass, making them sustainable chiral
building blocks for organic synthesis. The demand for chiral saturated
heterocyclic rings for pharmaceutical applications is increasing as
they provide well-defined three-dimensional frameworks that show increased
metabolic resistance. A range of sugar thioacetals can be dehydrated
selectively at C-2 under mild basic conditions, and the resulting
ketene thioacetals can be applied to the production of useful chiral
building blocks via further selective dehydration reactions.
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Affiliation(s)
- Rachel Szpara
- Department of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Alexander Goyder
- Department of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Michael J Porter
- Department of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Helen C Hailes
- Department of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Tom D Sheppard
- Department of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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5
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Coomber CE, Porter MJ, Aliev AE, Smith PD, Sheppard TD. Tuning Reactivity in Pd‐catalysed C(
sp
3
)‐H Arylations via Directing Group Modifications and Solvent Selection. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Charlotte E. Coomber
- Department of Chemistry Christopher Ingold Laboratories University College London 20 Gordon Street London WC1H 0AJ U.K
| | - Michael J. Porter
- Department of Chemistry Christopher Ingold Laboratories University College London 20 Gordon Street London WC1H 0AJ U.K
| | - Abil E. Aliev
- Department of Chemistry Christopher Ingold Laboratories University College London 20 Gordon Street London WC1H 0AJ U.K
| | - Peter D. Smith
- Early Chemical Development Pharmaceutical Sciences, R&D, AstraZeneca Macclesfield U.K
| | - Tom D. Sheppard
- Department of Chemistry Christopher Ingold Laboratories University College London 20 Gordon Street London WC1H 0AJ U.K
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6
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Laserna V, Porter MJ, Sheppard TD. Gold-Catalyzed Hydroamination of Propargylic Alcohols: Controlling Divergent Catalytic Reaction Pathways To Access 1,3-Amino Alcohols, 3-Hydroxyketones, or 3-Aminoketones. J Org Chem 2019; 84:11391-11406. [PMID: 31418573 DOI: 10.1021/acs.joc.9b00988] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A versatile approach to the valorization of propargylic alcohols is reported, enabling controlled access to three different products from the same starting materials. First, a general method for the hydroamination of propargylic alcohols with anilines is described using gold catalysis to give 3-hydroxyimines with complete regioselectivity. These 3-hydroxyimines can be reduced to give 1,3-amino alcohols with high syn selectivity. Alternatively, by using a catalytic quantity of aniline, 3-hydroxyketones can be obtained in high yield directly from propargylic alcohols. Further manipulation of the reaction conditions enables the selective formation of 3-aminoketones via a rearrangement/hydroamination pathway. The utility of the new chemistry was exemplified by the one-pot synthesis of a selection of N-arylpyrrolidines and N-arylpiperidines. A mechanism for the hydroamination has been proposed on the basis of experimental studies and density functional theory calculations.
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Affiliation(s)
- Victor Laserna
- Department of Chemistry, Christopher Ingold Laboratories , University College London , 20 Gordon Street , London WC1H 0AJ , U.K
| | - Michael J Porter
- Department of Chemistry, Christopher Ingold Laboratories , University College London , 20 Gordon Street , London WC1H 0AJ , U.K
| | - Tom D Sheppard
- Department of Chemistry, Christopher Ingold Laboratories , University College London , 20 Gordon Street , London WC1H 0AJ , U.K
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7
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Coomber CE, Laserna V, Martin LT, Smith PD, Hailes HC, Porter MJ, Sheppard TD. Catalytic direct amidations in tert-butyl acetate using B(OCH 2CF 3) 3. Org Biomol Chem 2019; 17:6465-6469. [PMID: 31225568 PMCID: PMC6724682 DOI: 10.1039/c9ob01012b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
B(OCH2CF3)3-catalysed direct amidations of challenging substrates (polar heteroycles, poorly nucleophilic anilines) work well in tBuOAc under Dean–Stark conditions.
Catalytic direct amidation reactions have been the focus of considerable recent research effort, due to the widespread use of amide formation processes in pharmaceutical synthesis. However, the vast majority of catalytic amidations are performed in non-polar solvents (aromatic hydrocarbons, ethers) which are typically undesirable from a sustainability perspective, and are often poor at solubilising polar carboxylic acid and amine substrates. As a consequence, most catalytic amidation protocols are unsuccessful when applied to polar and/or functionalised substrates of the kind commonly used in medicinal chemistry. In this paper we report a practical and useful catalytic direct amidation reaction using tert-butyl acetate as the reaction solvent. The use of an ester solvent offers improvements in terms of safety and sustainability, but also leads to an improved reaction scope with regard to polar substrates and less nucleophilic anilines, both of which are important components of amides used in medicinal chemistry. An amidation reaction was scaled up to 100 mmol and proceeded with excellent yield and efficiency, with a measured process mass intensity of 8.
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Affiliation(s)
- Charlotte E Coomber
- Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
| | - Victor Laserna
- Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
| | - Liam T Martin
- Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
| | - Peter D Smith
- Early Chemical Development, Pharmaceutical Sciences, IMED Biotech Unit, AstraZeneca, Macclesfield SK10 2NA, UK
| | - Helen C Hailes
- Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
| | - Michael J Porter
- Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
| | - Tom D Sheppard
- Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, UK.
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8
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Shannonhouse LR, Elston N, Lin YWD, Mize MC, Rumsey A, Rice R, Wanna R, Porter MJ. Suicide Intervention Training for Counselor Trainees: A Quasi-Experimental Study on Skill Retention. Counselor Education and Supervision 2018. [DOI: 10.1002/ceas.12110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Nikki Elston
- Department of Counseling and Psychological Services, Georgia State University
| | | | - Mary Chase Mize
- Department of Counseling and Psychological Services, Georgia State University
| | - Amanda Rumsey
- Department of Counseling and Psychological Services, Georgia State University
| | - Robert Rice
- Department of Counseling and Psychological Services, Georgia State University
| | - Reema Wanna
- Department of Counseling and Psychological Services, Georgia State University
| | - Michael J. Porter
- Department of Earth, Ocean, and Atmospheric Science, Florida State University
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9
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Gendron T, Sander K, Cybulska K, Benhamou L, Sin PKB, Khan A, Wood M, Porter MJ, Årstad E. Ring-Closing Synthesis of Dibenzothiophene Sulfonium Salts and Their Use as Leaving Groups for Aromatic 18F-Fluorination. J Am Chem Soc 2018; 140:11125-11132. [PMID: 30132661 PMCID: PMC6128620 DOI: 10.1021/jacs.8b06730] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Herein, we report a novel intramolecular ring-closing reaction of biaryl thioethers that give access to highly functionalized dibenzothiophene sulfonium salts under mild conditions. The resulting precursors react regioselectively with [18F]fluoride to give [18F]fluoroarenes in predictable radiochemical yields. The strategy expands the available radiochemical space and provides superior labeling efficiency for clinically relevant PET tracers.
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Affiliation(s)
- Thibault Gendron
- Institute of Nuclear Medicine , University College London , 235 Euston Road (T-5) , London NW1 2BU , United Kingdom.,Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Kerstin Sander
- Institute of Nuclear Medicine , University College London , 235 Euston Road (T-5) , London NW1 2BU , United Kingdom.,Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Klaudia Cybulska
- Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Laure Benhamou
- Institute of Nuclear Medicine , University College London , 235 Euston Road (T-5) , London NW1 2BU , United Kingdom.,Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Pak Kwan Brian Sin
- Institute of Nuclear Medicine , University College London , 235 Euston Road (T-5) , London NW1 2BU , United Kingdom.,Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Aqsa Khan
- Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Michael Wood
- Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Michael J Porter
- Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
| | - Erik Årstad
- Institute of Nuclear Medicine , University College London , 235 Euston Road (T-5) , London NW1 2BU , United Kingdom.,Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , United Kingdom
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10
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Coomber CE, Benhamou L, Bučar DK, Smith PD, Porter MJ, Sheppard TD. Silver-Free Palladium-Catalyzed C(sp3)–H Arylation of Saturated Bicyclic Amine Scaffolds. J Org Chem 2017; 83:2495-2503. [DOI: 10.1021/acs.joc.7b02665] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Charlotte E. Coomber
- Department
of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Laure Benhamou
- Department
of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Dejan-Krešimir Bučar
- Department
of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Peter D. Smith
- Early
Chemical Development, Pharmaceutical Sciences, IMED Biotech Unit, AstraZeneca, Macclesfield SK10 2NA, U.K
| | - Michael J. Porter
- Department
of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Tom D. Sheppard
- Department
of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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11
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Abstract
We report a method for the direct and rapid conversion of primary and secondary alcohols to the corresponding phosphorothiolates in yields ranging from 64% to 97%, using as a coupling agent the iminium salt prepared from N,N-dimethylthioformamide and Meerwein's salt. Selective reaction of primary alcohols in the presence of secondary alcohols is possible. The reaction of secondary alcohols proceeds stereospecifically with inversion of configuration.
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Affiliation(s)
- Helen Grounds
- Department of Chemistry, University College London , Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Kristaps Ermanis
- Department of Chemistry, University College London , Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Sophie A Newgas
- Department of Chemistry, University College London , Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Michael J Porter
- Department of Chemistry, University College London , Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
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12
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Parkes MA, Phillips C, Porter MJ, Fielding HH. Controlling electron emission from the photoactive yellow protein chromophore by substitution at the coumaric acid group. Phys Chem Chem Phys 2016; 18:10329-36. [PMID: 27025529 DOI: 10.1039/c6cp00565a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Understanding how the interactions between a chromophore and its surrounding protein control the function of a photoactive protein remains a challenge. Here, we present the results of photoelectron spectroscopy measurements and quantum chemistry calculations aimed at investigating how substitution at the coumaryl tail of the photoactive yellow protein chromophore controls competing relaxation pathways following photoexcitation of isolated chromophores in the gas phase with ultraviolet light in the range 350-315 nm. The photoelectron spectra are dominated by electrons resulting from direct detachment and fast detachment from the 2(1)ππ* state but also have a low electron kinetic energy component arising from autodetachment from lower lying electronically excited states or thermionic emission from the electronic ground state. We find that substituting the hydrogen atom of the carboxylic acid group with a methyl group lowers the threshold for electron detachment but has very little effect on the competition between the different relaxation pathways, whereas substituting with a thioester group raises the threshold for electron detachment and appears to 'turn off' the competing electron emission processes from lower lying electronically excited states. This has potential implications in terms of tuning the light-induced electron donor properties of photoactive yellow protein.
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Affiliation(s)
- Michael A Parkes
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
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13
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Peveler WJ, Roldan A, Hollingsworth N, Porter MJ, Parkin IP. Multichannel Detection and Differentiation of Explosives with a Quantum Dot Array. ACS Nano 2016; 10:1139-46. [PMID: 26579950 DOI: 10.1021/acsnano.5b06433] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The sensing and differentiation of explosive molecules is key for both security and environmental monitoring. Single fluorophores are a widely used tool for explosives detection, but a fluorescent array is a more powerful tool for detecting and differentiating such molecules. By combining array elements into a single multichannel platform, faster results can be obtained from smaller amounts of sample. Here, five explosives are detected and differentiated using quantum dots as luminescent probes in a multichannel platform: 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), tetryl (2,4,6-trinitrophenylmethylnitramine), cyclotrimethylenetrinitramine (RDX), and pentaerythritol tetranitrate (PETN). The sharp, variable emissions of the quantum dots, from a single excitation wavelength, make them ideal for such a system. Each color quantum dot is functionalized with a different surface receptor via a facile ligation process. These receptors undergo nonspecific interactions with the explosives, inducing variable fluorescence quenching of the quantum dots. Pattern analysis of the fluorescence quenching data allows for explosive detection and identification with limits-of-detection in the ppb range.
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Affiliation(s)
- William J Peveler
- Department of Security and Crime Science, University College London , 35 Tavistock Sq., London WC1H 9EZ, United Kingdom
- Department of Chemistry, University College London , 20 Gordon St., London WC1H 0AJ, United Kingdom
| | - Alberto Roldan
- Department of Chemistry, University College London , 20 Gordon St., London WC1H 0AJ, United Kingdom
- School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Nathan Hollingsworth
- Department of Chemistry, University College London , 20 Gordon St., London WC1H 0AJ, United Kingdom
| | - Michael J Porter
- Department of Chemistry, University College London , 20 Gordon St., London WC1H 0AJ, United Kingdom
| | - Ivan P Parkin
- Department of Chemistry, University College London , 20 Gordon St., London WC1H 0AJ, United Kingdom
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14
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Abstract
Based on detailed analysis of newly acquired NMR data, we show that the previously revised structure of tagetitoxin is incorrect. A new structure of tagetitoxin is proposed which is consistent with the NMR and MS data.
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Affiliation(s)
- Abil E Aliev
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
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15
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Foster RW, Benhamou L, Porter MJ, Bučar DK, Hailes HC, Tame CJ, Sheppard TD. Irreversible endo-selective diels-alder reactions of substituted alkoxyfurans: a general synthesis of endo-cantharimides. Chemistry 2015; 21:6107-14. [PMID: 25756502 PMCID: PMC4406157 DOI: 10.1002/chem.201406286] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Indexed: 11/29/2022]
Abstract
The [4+2] cycloaddition of 3-alkoxyfurans with N-substituted maleimides provides the first general route for preparing endo-cantharimides. Unlike the corresponding reaction with 3H furans, the reaction can tolerate a broad range of 2-substitued furans including alkyl, aromatic, and heteroaromatic groups. The cycloaddition products were converted into a range of cantharimide products with promising lead-like properties for medicinal chemistry programs. Furthermore, the electron-rich furans are shown to react with a variety of alternative dienophiles to generate 7-oxabicyclo[2.2.1]heptane derivatives under mild conditions. DFT calculations have been performed to rationalize the activation effect of the 3-alkoxy group on a furan Diels-Alder reaction.
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Affiliation(s)
- Robert W Foster
- Department of Chemistry, University College London, Christopher Ingold Laboratories20 Gordon Street, London, WC1H 0AJ (UK)
| | - Laure Benhamou
- Department of Chemistry, University College London, Christopher Ingold Laboratories20 Gordon Street, London, WC1H 0AJ (UK)
| | - Michael J Porter
- Department of Chemistry, University College London, Christopher Ingold Laboratories20 Gordon Street, London, WC1H 0AJ (UK)
| | - Dejan-Krešimir Bučar
- Department of Chemistry, University College London, Christopher Ingold Laboratories20 Gordon Street, London, WC1H 0AJ (UK)
| | - Helen C Hailes
- Department of Chemistry, University College London, Christopher Ingold Laboratories20 Gordon Street, London, WC1H 0AJ (UK)
| | - Christopher J Tame
- GlaxoSmithKline, Medicines Research CentreGunnels Wood Road, Stevenage, Herts, SG1 2NY (UK)
| | - Tom D Sheppard
- Department of Chemistry, University College London, Christopher Ingold Laboratories20 Gordon Street, London, WC1H 0AJ (UK)
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Aliev AE, Arendorf JRT, Pavlakos I, Moreno RB, Porter MJ, Rzepa HS, Motherwell WB. Surfing π Clouds for Noncovalent Interactions: Arenes versus Alkenes. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409672] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Aliev AE, Arendorf JRT, Pavlakos I, Moreno RB, Porter MJ, Rzepa HS, Motherwell WB. Surfing π Clouds for Noncovalent Interactions: Arenes versus Alkenes. Angew Chem Int Ed Engl 2014; 54:551-5. [DOI: 10.1002/anie.201409672] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Indexed: 11/07/2022]
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Wright TC, Stoler MH, Agreda PM, Beitman GH, Gutierrez EC, Harris JM, Koch KR, Kuebler M, LaViers WD, Legendre BL, Leitch SV, Maus CE, McMillian RA, Nussbaumer WA, Palmer MLR, Porter MJ, Richart GA, Schwab RJ, Vaughan LM. Clinical performance of the BD Onclarity HPV assay using an adjudicated cohort of BD SurePath liquid-based cytology specimens. Am J Clin Pathol 2014; 142:43-50. [PMID: 24926084 DOI: 10.1309/ajcp53kmhnrdicbl] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES To compare the performance of the BD Onclarity HPV Assay (BD Diagnostics, Sparks, MD) in BD SurePath liquid-based cytology media with that of Hybrid Capture 2 (HC2, Qiagen, Germantown, MD) samples co-collected in specimen transport medium in an adjudicated patient cohort. METHODS The performance of the BD Onclarity HPV Assay using BD SurePath media was compared with that of HC2 samples co-collected in specimen transport medium using 541 archived samples from a multicenter US clinical trial with histologically adjudicated cervical biopsy specimens. RESULTS The sensitivity for cervical intraepithelial neoplasia (CIN) 2 positivity (n - 104) was 90.4% (95% confidence interval [CI], 83-95) and 93.3% (95% CI, 87-97) and specificity was 76.9% (95% CI, 73-81) and 77.8% (95% CI, 74-82) for the BD assay and HC2, respectively. Nine cases of CIN 2+ had results discordant with the high-risk HPV assay. All were found to have been correctly classified with the BD assay using a novel WAVE denaturing high-performance liquid chromatography double-stranded DNA sequencing method. CONCLUSIONS The clinical performance of The BD Onclarity HPV Assay with respect to histology end points was similar to HC2. Moreover, discordant analysis revealed improved performance of the BD assay with respect to ability to provide extended genotyping information and lack of cross-reactivity with low-risk HPV types associated with cellular abnormalities. The relative risks for CIN 3 disease for HPV 31 and HPV 33/58 (combined) were comparable to that of HPV 18 in this population, suggesting that these genotypes may warrant monitoring in future studies.
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Affiliation(s)
- Thomas C. Wright
- Department of Pathology, College of Physicians and Surgeons, Columbia University, NY
| | - Mark H. Stoler
- Department of Pathology, University of Virginia Health System, Charlottesville, VA
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Chavda JK, Procopiou PA, Horton PN, Coles SJ, Porter MJ. Synthetic Studies Towards the Core Structure of Nakadomarin A by a Thioamide-Based Strategy. European J Org Chem 2014; 2014:129-139. [PMID: 24829538 PMCID: PMC4015372 DOI: 10.1002/ejoc.201301063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Indexed: 11/29/2022]
Abstract
The tricyclic BCD substructure of the marine natural product nakadomarin A has been synthesised. The strategy utilised a key carbon-carbon bond-forming reaction between a furan and an N-acyliminium ion derived from a secondary thiolactam. In addition, a novel three-component coupling reaction between a thioamide, an allylic bromide and an isocyanate, leading to the establishment of two new stereogenic centres, is reported. Two key steps in a projected total synthesis of nakadomarin A have been realised by using the unique chemistry of thioamides. Formation of the carbocyclic B ring can be effected by nucleophilic attack of a furan on a thiolactam-derived iminium ion, and the key quaternary centre can be established by a novel three-component coupling reaction.
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Affiliation(s)
- Jai K Chavda
- Department of Chemistry, University College London Christopher Ingold Building, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Panayiotis A Procopiou
- GlaxoSmithKline Research & Development Limited, Medicines Research Centre Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Peter N Horton
- UK National Crystallography Service, School of Chemistry, University of Southampton Southampton, SO17 1BJ, UK
| | - Simon J Coles
- UK National Crystallography Service, School of Chemistry, University of Southampton Southampton, SO17 1BJ, UK
| | - Michael J Porter
- Department of Chemistry, University College London Christopher Ingold Building, 20 Gordon Street, London, WC1H 0AJ, UK
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Ellwood AR, Mortimer AJP, Goodman JM, Porter MJ. Reversal of facial selectivity in a thia-Claisen rearrangement by incorporation of a vinylic bromine substituent. Org Biomol Chem 2013; 11:7530-9. [PMID: 24091642 DOI: 10.1039/c3ob41580e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thia-Claisen rearrangements have been carried out using N-benzylpyrrolidine-2-thione and chiral allylic bromides derived from D-mannitol. Introduction of a bromine atom onto the double bond of the allylic bromide reverses the sense of diastereoselectivity in the [3,3]-sigmatropic rearrangement. Density functional theory calculations lead us to rationalise the observed selectivity in terms of a Cíeplak effect.
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Affiliation(s)
- Adam R Ellwood
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London, WC1H 0AJ, UK.
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Rotoloni CL, LaRosa JM, Porter MJ, Kelly LA, Nega K, Wolfson E, Komastu Y, Kosovec JE, Kasi PM, Hoppo T, Zaidi AH, Jobe BA. Abstract A48: Enhanced efficacy of cisplatin and 5-fluorouracil combination with AUY-922 in esophageal adenocarcinoma cells. Cancer Res 2013. [DOI: 10.1158/1538-7445.fbcr13-a48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Esophageal Adenocarcinoma (EAC) continues to rise in incidence, with prognosis remaining poor despite advances in multimodality therapy. Several novel target agents are now being explored as an option for treating EAC. One potential target is heat shock protein 90 (Hsp90), a chaperone protein that is involved in many diverse biological processes including cell signaling, proliferation, and survival. Many of the client proteins are known oncoproteins that allow Hsp90 to stabilize cancer cell growth by supporting proliferation and preventing apoptosis. The isoform, Hsp90β, is constituently expressed, while Hsp90α is inducible during times of stress, with expression increased 2-10 fold in cancers. Our hypothesis is that Hsp90 inhibition, in combination with standard chemotherapeutic drugs, will cause EAC cancer cells to be more susceptible to apoptosis and reduce the rate of proliferation.
Methods: EAC cell lines, OE19 and OE33, were used to evaluate the effects of Hsp90 inhibitor, AUY-922, in cancer cell growth and apoptosis. ELISA of WST-1 and BrdU were used to determine the effective dosage and assess proliferation. Pathway inhibition was evaluated by Western Blot of Hsp90α and Hsp70. OE19, OE33, and patient samples of EAC tumor and gastroesophageal reflux tissue were used to assess the gene expression of Hsp90 and several client protein pathways by reverse transcription polymerase chain reaction (RT-PCR).
Results: The ED50 of AUY-922 was determined to be 30ηM. A combination of chemotherapeutic drugs, cisplatin and 5-fluorouracil (5-Fu), along with AUY-922 showed significantly decreased proliferation compared to untreated and single agent treated cell lines. Western blot demonstrated that Hsp90 was inhibited by AUY-922 treatment, by a decrease in expression of Hsp90α, and an increase in the expression of Hsp70. RT-PCR in the cell line treatment groups showed an impact on many client oncoproteins involved in cancer cell survival and Hsp90 was shown to be upregulated in tumor samples when compared to normal GERD samples.
Conclusion: The use of Hsp90 inhibitor, AUY-922, leads to reduced Hsp90 pathway expression, resulting in a degradation of many Hsp90 client proteins involved in cancer genesis. Cell proliferation was decreased with AUY-922 treatment, with the greatest demonstrated effect when used in combination with cisplatin and 5-Fu. Therefore, Hsp90 inhibition may have an application in multimodal EAC chemotherapy.
Citation Format: Christina L. Rotoloni, Jaclyn M. LaRosa, Michael J. Porter, Lori A. Kelly, Katherine Nega, Emily Wolfson, Yoshihiro Komastu, Juliann E. Kosovec, Pashtoon M. Kasi, Toshitaka Hoppo, Ali H. Zaidi, Blair A. Jobe. Enhanced efficacy of cisplatin and 5-fluorouracil combination with AUY-922 in esophageal adenocarcinoma cells. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr A48.
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Affiliation(s)
| | | | | | - Lori A. Kelly
- 1Western Pennsylvania Health System, Pittsburgh, PA,
| | | | - Emily Wolfson
- 1Western Pennsylvania Health System, Pittsburgh, PA,
| | | | | | | | | | - Ali H. Zaidi
- 1Western Pennsylvania Health System, Pittsburgh, PA,
| | - Blair A. Jobe
- 1Western Pennsylvania Health System, Pittsburgh, PA,
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Anderson JC, Kalogirou AS, Porter MJ, Tizzard GJ. Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step. Beilstein J Org Chem 2013; 9:1737-44. [PMID: 24062836 PMCID: PMC3778392 DOI: 10.3762/bjoc.9.200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/01/2013] [Indexed: 01/01/2023] Open
Abstract
Piperazirum, isolated from Arum palaestinum Boiss, was originally assigned as r-3,c-5-diisobutyl-c-6-isopropylpiperazin-2-one. The reported structure was synthesised diastereoselectively using a key nitro-Mannich reaction to set up the C5/C6 relative stereochemistry. The structure was unambiguously assigned by single crystal X-ray diffraction but the spectroscopic data did not match those reported for the natural product. The structure of the natural product must therefore be revised.
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Affiliation(s)
- James C Anderson
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
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Price Mortimer AJ, Plet JRH, Obasanjo OA, Kaltsoyannis N, Porter MJ. Inter- and intramolecular reactions of 1-deoxy-1-thio-1,6-anhydrosugars with α-diazoesters: synthesis of the tagetitoxin core by photochemical ylide rearrangement. Org Biomol Chem 2012; 10:8616-27. [DOI: 10.1039/c2ob26308d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Affiliation(s)
- Adam R. Ellwood
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Michael J. Porter
- Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ, U.K
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Affiliation(s)
- Anne J. Price Mortimer
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Abil E. Aliev
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Derek A. Tocher
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Michael J. Porter
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, U.K
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Price Mortimer AJ, Pang PS, Aliev AE, Tocher DA, Porter MJ. Concise synthesis of bicyclic aminals and their evaluation as precursors to the sarain core. Org Biomol Chem 2008; 6:2941-51. [DOI: 10.1039/b806031b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fuelberg HE, Porter MJ, Kiley CM, Halland JJ, Morse D. Meteorological conditions and anomalies during the Intercontinental Chemical Transport Experiment–North America. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007734] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Weaver JC, Aizenberg J, Fantner GE, Kisailus D, Woesz A, Allen P, Fields K, Porter MJ, Zok FW, Hansma PK, Fratzl P, Morse DE. Hierarchical assembly of the siliceous skeletal lattice of the hexactinellid sponge Euplectella aspergillum. J Struct Biol 2007; 158:93-106. [PMID: 17175169 DOI: 10.1016/j.jsb.2006.10.027] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 10/24/2006] [Accepted: 10/25/2006] [Indexed: 11/22/2022]
Abstract
Despite its inherent mechanical fragility, silica is widely used as a skeletal material in a great diversity of organisms ranging from diatoms and radiolaria to sponges and higher plants. In addition to their micro- and nanoscale structural regularity, many of these hard tissues form complex hierarchically ordered composites. One such example is found in the siliceous skeletal system of the Western Pacific hexactinellid sponge, Euplectella aspergillum. In this species, the skeleton comprises an elaborate cylindrical lattice-like structure with at least six hierarchical levels spanning the length scale from nanometers to centimeters. The basic building blocks are laminated skeletal elements (spicules) that consist of a central proteinaceous axial filament surrounded by alternating concentric domains of consolidated silica nanoparticles and organic interlayers. Two intersecting grids of non-planar cruciform spicules define a locally quadrate, globally cylindrical skeletal lattice that provides the framework onto which other skeletal constituents are deposited. The grids are supported by bundles of spicules that form vertical, horizontal and diagonally ordered struts. The overall cylindrical lattice is capped at its upper end by a terminal sieve plate and rooted into the sea floor at its base by a flexible cluster of barbed fibrillar anchor spicules. External diagonally oriented spiral ridges that extend perpendicular to the surface further strengthen the lattice. A secondarily deposited laminated silica matrix that cements the structure together additionally reinforces the resulting skeletal mass. The mechanical consequences of each of these various levels of structural complexity are discussed.
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Affiliation(s)
- James C Weaver
- Department of Molecular, Cellular and Developmental Biology, Institute for Collaborative Biotechnologies, and the Materials Research Laboratory, University of California, Santa Barbara, CA 93106, USA
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Affiliation(s)
- Salma Ishaq
- a Department of Chemistry , University College London , London, UK
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Yao D, Alexander CL, Quinn JA, Porter MJ, Wu H, Greenhalgh DA. PTEN loss promotes rasHa-mediated papillomatogenesis via dual up-regulation of AKT activity and cell cycle deregulation but malignant conversion proceeds via PTEN-associated pathways. Cancer Res 2006; 66:1302-12. [PMID: 16452183 DOI: 10.1158/0008-5472.can-05-2341] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PTEN tumor suppressor gene failure in ras(Ha)-activated skin carcinogenesis was investigated by mating exon 5 floxed-PTEN (Delta5PTEN) mice to HK1.ras mice that expressed a RU486-inducible cre recombinase (K14.creP). PTEN inactivation in K14.cre/PTEN(flx/flx) keratinocytes resulted in epidermal hyperplasia/hyperkeratosis and novel 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted papillomas, whereas HK1.ras/K14.cre/PTEN(flx/flx) cohorts displayed a rapid onset of papillomatogenesis due to a synergism of increased AKT activity and extracellular signal-regulated kinase (ERK) elevation. High 5-bromo-4-deoxyuridine labeling in Delta5PTEN papillomas showed that a second promotion mechanism centered on failures in cell cycle control. Elevated cyclin D1 was associated with both HK1.ras/ERK- and Delta5PTEN-mediated AKT signaling, whereas cyclin E2 overexpression seemed dependent on PTEN loss. Spontaneous HK1.ras/Delta5PTEN malignant conversion was rare, whereas TPA promotion resulted in conversion with high frequency. On comparison with all previous HK1.ras carcinomas, such TPA-induced carcinomas expressed atypical retention of keratin K1 and lack of K13, a unique marker profile exhibited by TPA-induced K14.cre/PTEN(flx/flx) papillomas that also lacked endogenous c-ras(Ha) activation. Moreover, in all PTEN-null tumors, levels of ras(Ha)-associated total ERK protein became reduced, whereas phosphorylated ERK and cyclin D1 were lowered in late-stage papillomas returning to elevated levels, alongside increased cyclin E2 expression, in TPA-derived carcinomas. Thus, during early papillomatogenesis, PTEN loss promotes ras(Ha) initiation via elevation of AKT activity and synergistic failures in cyclin regulation. However, in progression, reduced ras(Ha)-associated ERK protein and activity, increased Delta5PTEN-associated cyclin E2 expression, and unique K1/K13 profiles following TPA treatment suggest that PTEN loss, rather than ras(Ha) activation, gives rise to a population of cells with greater malignant potential.
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Affiliation(s)
- Denggao Yao
- Section of Squamous Cell Biology and Dermatology, Division of Cancer Sciences and Molecular Pathology, Glasgow University, Glasgow G11 6NU, Scotland, UK
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Monksfield P, Porter MJ. Tophaceous gout presenting as a dorsal nasal hump. J Laryngol Otol 2006; 120:161. [PMID: 16535777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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Abstract
A synthesis of the 9-oxa-3-thiabicyclo[3.3.1]nonane ring system, which constitutes the core of the RNA polymerase inhibitor tagetitoxin, has been achieved through cyclisation of a thiol onto an electrophilic ketone.
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Affiliation(s)
- Julien R H Plet
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London, UKWC1H 0AJ
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Nandra GS, Pang PS, Porter MJ, Elliott JM. Synthesis of Vinylogous Carbamates by Rhodium(II)-Catalyzed Olefination of Tertiary Formamides with a Silylated Diazoester. Org Lett 2005; 7:3453-5. [PMID: 16048315 DOI: 10.1021/ol0510872] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Treatment of tertiary formamides with a silylated diazoester in the presence of a rhodium(II) catalyst leads to the formation of 3-amino-2-silyloxyacrylates in good yield. No olefination is observed if a nonsilylated diazo compound is employed. [reaction: see text]
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Affiliation(s)
- Gurdeep S Nandra
- Department of Chemistry, University College London, Christopher Ingold Building, 20 Gordon Street, London WC1H 0AJ, UK
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Porter MJ, Morton JB, Denman R, Lin AC, Tierney S, Santucci PA, Cai JJ, Madsen N, Wilber DJ. Influence of age and gender on the mechanism of supraventricular tachycardia. Heart Rhythm 2004; 1:393-6. [PMID: 15851189 DOI: 10.1016/j.hrthm.2004.05.007] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Accepted: 05/14/2004] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The objective of this study was to determine the impact of age and gender on the mechanism of paroxysmal supraventricular tachycardia (PSVT). BACKGROUND Previous studies have indicated that PSVT mechanism may be influenced by age and gender, but contemporary data are limited. METHODS In 1,754 patients undergoing catheter ablation of 1,856 PSVTs between 1991 and 2003, the mechanism was classified as atrioventricular reentrant tachycardia (AVRT), atrioventricular nodal reentrant tachycardia (AVNRT), or atrial tachycardia (AT). Patients with inappropriate sinus tachycardia, atrial flutter, atrial fibrillation, and age <5 years were excluded. RESULTS The mean age was 45 +/- 19 years (range 5-96), and the majority were women (62%). Overall, AVNRT was the predominant mechanism (n = 1,042 [56%]), followed by AVRT (n = 500 [27%]) and AT (n = 315 [17%]). There was a strong relationship between age and PSVT mechanism; the proportion of AVRT in both sexes decreased with age, whereas AVNRT and AT increased (PM < .001 by ANOVA). The majority of patients with AVRT were men (273/500 [54.6%]), whereas the majority of patients with AVNRT and AT were women (727/1,042 [70%] and 195/315 [62%], respectively). The distribution of PSVT mechanism was significantly influenced by gender (P < .001). In women, 63% had AVNRT, 20% had AVRT, and 17.0% had AT. In men, 45% had AVNRT, 39% had AVRT, and 17% had AT. AVNRT replaced AVRT as the dominant PSVT mechanism at age 40 in men and at age 10 in women. CONCLUSIONS The mechanism of PSVT in patients presenting for ablation is significantly influenced by both age and gender.
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Affiliation(s)
- Michael J Porter
- Loyola Cardiovascular Institute, Loyola University Medical Center, Maywood, Illinois 60153, USA
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Weller MD, Porter MJ, Rowlands J. An audit of pharyngeal pouch surgery using endoscopic stapling. The patient's viewpoint. Eur Arch Otorhinolaryngol 2003; 261:331-3. [PMID: 14551789 DOI: 10.1007/s00405-003-0689-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2003] [Accepted: 08/22/2003] [Indexed: 11/24/2022]
Abstract
We report an audit designed to assess patient satisfaction resulting from pharyngeal pouch surgery using an endoscopic stapler. A personal series of 16 patients all operated on by the senior author over a 3-year period is reported. Information was gathered using a retrospective telephone questionnaire to establish pre- and postoperative symptoms, complications of surgery and patient satisfaction. This showed endoscopic pharyngeal pouch surgery to be successful in the majority of cases. Eighty-seven percent of patients felt better as a result of surgery. Seventy-five percent had no symptoms postoperatively. This series shows that surgery on pharyngeal pouches results in significant improvement in patient symptoms with minimal morbidity and mortality.
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Affiliation(s)
- M D Weller
- Department of Otorhinolaryngology, Worcestershire Royal Hospital, Worcester, UK.
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Porter MJ, Heidkamp MC, Scully BT, Patel N, Martin JL, Samarel AM. Isoenzyme-selective regulation of SERCA2 gene expression by protein kinase C in neonatal rat ventricular myocytes. Am J Physiol Cell Physiol 2003; 285:C39-47. [PMID: 12606313 DOI: 10.1152/ajpcell.00461.2002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Patients with cardiac hypertrophy and heart failure display abnormally slowed myocardial relaxation, which is associated with downregulation of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2) gene expression. We previously showed that SERCA2 downregulation can be simulated in cultured neonatal rat ventricular myocytes (NRVM) by treatment with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA). However, NRVM express three different PMA-sensitive PKC isoenzymes (PKCalpha, PKCepsilon, and PKCdelta), which may be differentially regulated and have specific functions in the cardiomyocyte. Therefore, in this study we used adenoviral vectors encoding wild-type (wt) and kinase-defective, dominant negative (dn) mutant forms of PKCalpha, PKCepsilon, and PKCdelta to analyze their individual effects in regulating SERCA2 gene expression in NRVM. Overexpression of wtPKCepsilon and wtPKCdelta, but not wtPKCalpha, was sufficient to downregulate SERCA2 mRNA levels, as assessed by Northern blotting and quantitative, real-time RT-PCR (69 +/- 7 and 61 +/- 9% of control levels for wtPKCepsilon and wtPKCdelta, respectively; P < 0.05 for each adenovirus; n = 8 experiments). Conversely, overexpression of all three dnPKCs appeared to significantly increase SERCA2 mRNA levels (dnPKCdelta > dnPKCepsilon > dnPKCalpha). dnPKCdelta overexpression produced the largest increase (2.8 +/- 1.0-fold; n = 11 experiments). However, PMA treatment was still sufficient to downregulate SERCA2 mRNA levels despite overexpression of each dominant negative mutant. These data indicate that the novel PKC isoenzymes PKCepsilon and PKCdelta selectively regulate SERCA2 gene expression in cardiomyocytes but that neither PKC alone is necessary for this effect if the other novel PKC can be activated.
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Affiliation(s)
- Michael J Porter
- The Cardiovascular Institute and Department of Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153, USA
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Bayer AL, Heidkamp MC, Patel N, Porter MJ, Engman SJ, Samarel AM. PYK2 expression and phosphorylation increases in pressure overload-induced left ventricular hypertrophy. Am J Physiol Heart Circ Physiol 2002; 283:H695-706. [PMID: 12124218 DOI: 10.1152/ajpheart.00021.2002] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Proline-rich tyrosine kinase 2 (PYK2) is a member of the focal adhesion kinase (FAK) family of nonreceptor protein tyrosine kinases. PYK2 has been implicated in linking G protein-coupled receptors to activation of mitogen-activated protein kinase cascades and cellular growth in a variety of cell types. To determine whether PYK2 expression and phosphorylation is altered in left ventricular (LV) myocardium undergoing LV hypertrophy (LVH) and heart failure in vivo, suprarenal abdominal aortic coarctation was performed in 160-g male Sprague-Dawley rats. Immunohistochemistry and Western blotting were performed on LV tissue 1, 8, and 24 wk after aortic banding. Aortic banding produced sustained hypertension and gradually developing LVH. PYK2 levels were increased 1.8 +/- 0.2-, 2.7 +/- 0.6-, and 2.0 +/- 0.2-fold in 1-, 8-, and 24-wk banded animals compared with their respective sham-operated controls. The increase in PYK2 expression was paralleled by an increase in PYK2 phosphorylation, both of which preceded the development of LVH. Immunohistochemistry revealed that enhanced PYK2 expression occurred predominantly in the cardiomyocyte population. Furthermore, there was a high degree of correlation (R = 0.75; P < 0.001) between the level of PYK2 and the degree of LVH in 24-wk sham and banded animals. In contrast, FAK levels and FAK phosphorylation were not increased before the development of LVH. However, there was a high degree of correlation (R = 0.68; P < 0.001) between the level of FAK and the degree of LVH in 24-wk sham and banded rats. There was also a significant increase in the ratio of phosphospecific anti-FAK to FAK at this time point. These data are consistent with a role for PYK2 in the induction of pressure overload-induced cardiomyocyte hypertrophy, and suggest that PYK2 and FAK have distinctly different roles in LVH progression.
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Affiliation(s)
- Allison L Bayer
- The Cardiovascular Institute and Department of Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 First Avenue, Maywood, IL 60153, USA
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Abstract
1,3-Oxathiolanes are efficiently converted, via sulfur ylide intermediates, to 1,4-oxathianes by ring expansion with a silylated diazoacetate in the presence of a copper catalyst.
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Affiliation(s)
- Maria Ioannou
- Department of Chemistry, University College London, 20 Gordon Street, London, UK WC1H OAJ
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Abstract
The use of polyamino acids in asymmetric organic synthesis is reviewed. Particular emphasis is placed on the asymmetric epoxidation of alpha,beta-unsaturated ketones with hydrogen peroxide in the presence of polyalanine or polyleucine, and further transformations of the epoxide products.
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Affiliation(s)
- M J Porter
- Department of Chemistry, University of Liverpool, UK
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Abstract
PURPOSE To determine results of various treatments for T3 fixed-cord lesions and the subset T3 glottic cancer in Auckland from 1979 to 1995. PATIENTS AND METHODS Data were collected retrospectively from a departmental database, and the notes were reviewed. Because of the difficulty in determining the subsite of some fixed-cord lesions, the entire group of T3 fixed-cord lesions was examined, and those tumors that were considered to be definitely arising from the glottis were then analyzed as a specific subset. RESULTS Fixed-cord lesions were diagnosed in 75 patients (21 supraglottic, 54 glottic). Primary surgery (total laryngectomy) was performed on 46 patients, primary radical dose radiotherapy was undertaken on 25 patients, and four patients were treated palliatively. For T3 fixed-cord lesions, disease-specific survival for radiotherapy and surgery was 36% and 66%, respectively, and 32% and 67%, respectively, for T3 glottic lesions. For both T3 fixed-cord and T3 glottic lesions, surgery produced significantly better survival than did radiotherapy (<60 Gy; P = .0157). With radiotherapy greater than 60 Gy, cancer of the larynx has been controlled in seven of 13 patients, although only five patients are alive, with a median follow-up of 24 months (range, 12-49 months). CONCLUSION Radiotherapy less than 60 Gy produced markedly inferior results to surgery for T3 fixed-cord lesions and T3 glottis in Auckland. Radiotherapy at more than 60 Gy shows promise, but an ongoing audit is essential to ensure that survival is similar to surgery and to that reported by those promoting organ-preservation protocols.
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Affiliation(s)
- M J Porter
- Department of Otolaryngology/Head and Neck Surgery, Green Lane Hospital, Auckland, New Zealand
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48
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Abstract
The great auricular nerve is routinely divided during the operation of parotidectomy, however, some surgeons have suggested that preserving the posterior branches reduces the area of post-operative anaesthesia. A prospective study was performed comparing the area of anaesthesia and hypoaesthesia in patients undergoing parotidectomy. In 20 patients the great auricular nerve was preserved and in 11 it was sacrificed. Mapping of the area of sensory loss at 2 weeks, 3, 6, 9 and 12 months showed that there was no difference between the two groups. The area of sensory loss decreased in an exponential fashion in both groups. The majority of the change occurred within 6 months. We conclude that preservation of the posterior branches of the great auricular nerve is unnecessary.
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Affiliation(s)
- M J Porter
- ENT Department, St. Michael's Hospital, Bristol, UK
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Abstract
Almost all the pathological and physiological process that effect the nose will change the volume of the airspace within it. This volume has previously been difficult to measure but a new method that calculates this space has been developed. A mechanical model was built to test the physical parameters involved in making volume measurements. The model demonstrated that a model sinus could be detected if the ostium was only 0.5 mm in diameter. It also showed that a mathematical model which described the volume of the space could be constructed. In vivo experiments showed that nasal volume can be measured in children as young as 4. In children, nasal volume correlates with age, height, and weight. They had a low coefficient of variation (7.1%) and a high test-retest correlation (r = 0.94). Adult nasal volume averaged 138 ml. The method is sensitive enough to detect the decongestant effect of xylometazoline in a group of 17 healthy volunteers (p < 0.01). There is no significant difference in the sensitivity to detect the decongestant effect of xylometazoline when compared with active anterior rhinometry, nasal peak flow, and acoustic rhinometry (range 80-95%).
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Affiliation(s)
- M J Porter
- ENT Department, St. Michael's Hospital, Bristol, UK.
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Porter MJ. The Lohr decision: FDA perspective and position. Food Drug Law J 1997; 52:7-11. [PMID: 10346705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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