1
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Pongener I, O'Shea C, Wootton H, Watkinson M, Miller GJ. Developments in the Chemical Synthesis of Heparin and Heparan Sulfate. CHEM REC 2021; 21:3238-3255. [PMID: 34523797 DOI: 10.1002/tcr.202100173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/19/2021] [Indexed: 11/08/2022]
Abstract
Heparin and heparan sulfate represent key members of the glycosaminoglycan family of carbohydrates and underpin considerable repertoires of biological importance. As such, their efficiency of synthesis represents a key requirement, to further understand and exploit the H/HS structure-to-biological function axis. In this review we focus on chemical approaches to and methodology improvements for the synthesis of these essential sugars (from 2015 onwards). We first consider advances in accessing the heparin-derived pentasaccharide anticoagulant fondaparinux. This is followed by heparan sulfate targets, including key building block synthesis, oligosaccharide construction and chemical sulfation techniques. We end with a consideration of technological improvements to traditional, solution-phase synthesis approaches that are increasingly being utilised.
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Affiliation(s)
- Imlirenla Pongener
- Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, ST5 5BG, Staffordshire, UK
| | - Conor O'Shea
- Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, ST5 5BG, Staffordshire, UK
| | - Hannah Wootton
- Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, ST5 5BG, Staffordshire, UK
| | - Michael Watkinson
- Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, ST5 5BG, Staffordshire, UK
| | - Gavin J Miller
- Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, ST5 5BG, Staffordshire, UK
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2
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Yuan D, Cai N, Xu J, Miao D, Zhang S, Woodfine SE, Plana D, Hawes CS, Watkinson M. A Series of Manganese(III) Salen Complexes as a Result of Team-Based Inquiry in a Transnational Education Programme. Chempluschem 2020; 85:1210-1219. [PMID: 32515150 DOI: 10.1002/cplu.202000337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/12/2020] [Indexed: 11/10/2022]
Abstract
The development of a team-based approach to research-led transnational practical chemistry teaching is described in which a team of five Chinese students on an articulated transnational degree programme, supported by a team of academic and technical staff, carried out a study examining the structural chemistry of a series of manganese(III) salen complexes. A series of four crystallographically characterized manganese(III) salen complexes with ancillary carboxylate ligands are reported here. The carboxylate coordination modes range from the bridging syn-anti μ2 -κO : κO' mode observed in the predominant cyclohexanoate and isobutyrate species, to a capping terminal monodentate mode for the adamantanoate species, and an unusual mixture of bridging and terminal coordination modes observed in a second minor phase of the cyclohexanoate species. The variation on extended structures based on the weakly interacting aliphatic backbones may provide a useful basis for further structural studies.
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Affiliation(s)
- Danlei Yuan
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom.,Nanjing Xiaozhuang University, Nanjing Shi, Jiangsu Sheng, P. R. China
| | - Ningqi Cai
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom.,Nanjing Xiaozhuang University, Nanjing Shi, Jiangsu Sheng, P. R. China
| | - Jingxi Xu
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom.,Nanjing Xiaozhuang University, Nanjing Shi, Jiangsu Sheng, P. R. China
| | - Danyang Miao
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom.,Nanjing Xiaozhuang University, Nanjing Shi, Jiangsu Sheng, P. R. China
| | - Sheng Zhang
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom.,Nanjing Xiaozhuang University, Nanjing Shi, Jiangsu Sheng, P. R. China
| | - Sian E Woodfine
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom
| | - Daniela Plana
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom
| | - Chris S Hawes
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom
| | - Michael Watkinson
- The Lennard Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Keele, ST5 5BG, United Kingdom
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3
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Abstract
Zn2+, as the second most abundant d-block metal in the human body, plays an important role in a wide range of biological processes, and the dysfunction of its homeostasis is related to many diseases, including Type 2 diabetes, Alzheimer's disease and prostate and breast cancers. Small molecule fluorescent probes, as effective tools for real-time imaging, have been widely used to study Zn2+ related processes. However, the failure to control their localisation in cells has limited their utility somewhat, as they are generally incapable of studying individual processes in a specific cellular location. This perspective presents an overview of the recent developments in specific organelle localised small molecule fluorescent Zn2+ probes and their application in biological milieu, which could help to extend our understanding of the mechanisms that cells use to respond to dysfunction of zinc homeostasis and its roles in disease initiation and development.
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Affiliation(s)
- Le Fang
- The Joseph Priestley Building, School of Biological and Chemical Science, Queen Mary University of London Mile End Road London E1 4NS UK
| | - Michael Watkinson
- The Lennard-Jones Laboratories, School of Chemical and Physical Science, Keele University ST5 5BG UK
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4
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Singh M, Watkinson M, Scanlan EM, Miller GJ. Illuminating glycoscience: synthetic strategies for FRET-enabled carbohydrate active enzyme probes. RSC Chem Biol 2020. [DOI: 10.1039/d0cb00134a] [Citation(s) in RCA: 2] [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] Open
Abstract
Carbohydrates are synthesised, refined and degraded by carbohydrate active enzymes. FRET is emerging as a powerful tool to monitor and quantify their activity as well as to test inhibitors as new drug candidates and monitor disease.
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Affiliation(s)
- Meenakshi Singh
- Lennard-Jones Laboratories
- School of Chemical and Physical Sciences
- Keele University
- Staffordshire
- UK
| | - Michael Watkinson
- Lennard-Jones Laboratories
- School of Chemical and Physical Sciences
- Keele University
- Staffordshire
- UK
| | - Eoin M. Scanlan
- School of Chemistry and Trinity Biomedical Sciences Institute
- Trinity College Dublin
- Dublin 2
- Ireland
| | - Gavin J. Miller
- Lennard-Jones Laboratories
- School of Chemical and Physical Sciences
- Keele University
- Staffordshire
- UK
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5
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Fang L, Trigiante G, Crespo-Otero R, Hawes CS, Philpott MP, Jones CR, Watkinson M. Endoplasmic reticulum targeting fluorescent probes to image mobile Zn 2. Chem Sci 2019; 10:10881-10887. [PMID: 32190243 PMCID: PMC7066664 DOI: 10.1039/c9sc04300d] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [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] [Received: 08/26/2019] [Accepted: 10/16/2019] [Indexed: 12/11/2022] Open
Abstract
Zn2+ plays an important role in the normal function of the endoplasmic reticulum (ER) and its deficiency can cause ER stress, which is related to a wide range of diseases. In order to provide tools to better understand the role of mobile Zn2+ in ER processes, the first custom designed ER-localised fluorescent Zn2+ probes have been developed through the introduction of a cyclohexyl sulfonylurea as an ER-targeting unit with different Zn2+ receptors. Experiments in vitro and in cellulo show that both probes have a good fluorescence switch on response to Zn2+, high selectivity over other cations, low toxicity, ER-specific targeting ability and are efficacious imaging agents for mobile Zn2+ in four different cell lines. Probe 9 has been used to detect mobile Zn2+ changes under ER stress induced by both tunicamycin or thapsigargin, which indicates that the new probes should allow a better understanding of the mechanisms cells use to respond to dysfunction of zinc homeostasis in the ER and its role in the initiation and progression of diseases to be developed.
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Affiliation(s)
- Le Fang
- School of Biological and Chemical Science , Queen Mary University of London , The Joseph Priestley Building, Mile End Road , London , E1 4NS , UK
| | - Giuseppe Trigiante
- Centre for Cutaneous Research , Institute of Cell and Molecular Science , Barts and The London School of Medicine and Dentistry , Queen Mary University of London , London E1 2AT , UK
| | - Rachel Crespo-Otero
- School of Biological and Chemical Science , Queen Mary University of London , The Joseph Priestley Building, Mile End Road , London , E1 4NS , UK
| | - Chris S Hawes
- The Lennard-Jones Laboratories , School of Chemical and Physical Science , Keele University , ST5 5BG , UK .
| | - Michael P Philpott
- Centre for Cutaneous Research , Institute of Cell and Molecular Science , Barts and The London School of Medicine and Dentistry , Queen Mary University of London , London E1 2AT , UK
| | - Christopher R Jones
- School of Biological and Chemical Science , Queen Mary University of London , The Joseph Priestley Building, Mile End Road , London , E1 4NS , UK
| | - Michael Watkinson
- The Lennard-Jones Laboratories , School of Chemical and Physical Science , Keele University , ST5 5BG , UK .
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6
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Fang L, Trigiante G, Crespo-Otero R, Philpott MP, Jones CR, Watkinson M. An alternative modular 'click-S NAr-click' approach to develop subcellular localised fluorescent probes to image mobile Zn 2+ . Org Biomol Chem 2019; 17:10013-10019. [PMID: 31621740 DOI: 10.1039/c9ob01855g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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
Zn2+ is involved in a number of biological processes and its wide-ranging roles at the subcellular level, especially in specific organelles, have not yet been fully established due to a lack of tools to image it effectively. We report a new and efficient modular double 'click' approach towards a range of sub-cellular localised probes for mobile zinc. Through this methodology, endoplasmic reticulum, mitochondria and lysosome localised probes were successfully prepared which show good fluorescence responses to mobile Zn2+in vitro and in cellulo whilst a non-targeting probe was synthesized as a control. The methodology appears to have wide-utility for the generation of sub-cellular localised probes by incorporating specific organelle targeting vectors for mobile Zn2+ imaging.
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Affiliation(s)
- Le Fang
- The Joseph Priestley Building, School of Biological and Chemical Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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7
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Ahmad N, Colak B, Gibbs MJ, Zhang DW, Gautrot JE, Watkinson M, Becer CR, Krause S. Peptide Cross-Linked Poly(2-oxazoline) as a Sensor Material for the Detection of Proteases with a Quartz Crystal Microbalance. Biomacromolecules 2019; 20:2506-2514. [PMID: 31244015 DOI: 10.1021/acs.biomac.9b00245] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Inflammatory conditions are frequently accompanied by increased levels of active proteases, and there is rising interest in methods for their detection to monitor inflammation in a point of care setting. In this work, new sensor materials for disposable single-step protease biosensors based on poly(2-oxazoline) hydrogels cross-linked with a protease-specific cleavable peptide are described. The performance of the sensor material was assessed targeting the detection of matrix metalloproteinase-9 (MMP-9), a protease that has been shown to be an indicator of inflammation in multiple sclerosis and other inflammatory conditions. Films of the hydrogel were formed on gold-coated quartz crystals using thiol-ene click chemistry, and the cross-link density was optimized. The degradation rate of the hydrogel was monitored using a quartz crystal microbalance (QCM) and showed a strong dependence on the MMP-9 concentration. A concentration range of 0-160 nM of MMP-9 was investigated, and a lower limit of detection of 10 nM MMP-9 was determined.
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Affiliation(s)
- Norlaily Ahmad
- School of Engineering and Materials Science , Queen Mary University of London , London , E1 4NS , United Kingdom.,Centre of Foundation Studies , Universiti Teknologi MARA , Cawangan Selangor, Kampus Dengkil , 43800 Dengkil , Selangor , Malaysia
| | - Burcu Colak
- School of Engineering and Materials Science , Queen Mary University of London , London , E1 4NS , United Kingdom
| | - Martin John Gibbs
- School of Engineering and Materials Science , Queen Mary University of London , London , E1 4NS , United Kingdom
| | - De-Wen Zhang
- Institute of Medical Engineering, School of Basic Medical Sciences , Xi'an Jiaotong University Health Science Center , Xi'an , 710061 , China
| | - Julien E Gautrot
- School of Engineering and Materials Science , Queen Mary University of London , London , E1 4NS , United Kingdom
| | - Michael Watkinson
- The Lennard-Jones Laboratories, School of Chemical and Physical Sciences , Keele University , Staffordshire , ST5 5BG , United Kingdom
| | - C Remzi Becer
- Department of Chemistry , University of Warwick , Coventry , CV47AL , United Kingdom
| | - Steffi Krause
- School of Engineering and Materials Science , Queen Mary University of London , London , E1 4NS , United Kingdom
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8
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Wu F, Zhou B, Wang J, Zhong M, Das A, Watkinson M, Hing K, Zhang DW, Krause S. Photoelectrochemical Imaging System for the Mapping of Cell Surface Charges. Anal Chem 2019; 91:5896-5903. [DOI: 10.1021/acs.analchem.9b00304] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Fan Wu
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
- Institute of Medical Engineering, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, 710061, China
| | - Bo Zhou
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Jian Wang
- Institute of Medical Engineering, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, 710061, China
| | - Muchun Zhong
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Anirban Das
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Michael Watkinson
- The Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Staffordshire, ST5 5BG, U.K
| | - Karin Hing
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - De-Wen Zhang
- Institute of Medical Engineering, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an, 710061, China
| | - Steffi Krause
- School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
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9
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Ahmad N, Colak B, Zhang DW, Gibbs MJ, Watkinson M, Becer CR, Gautrot JE, Krause S. Peptide Cross-Linked Poly (Ethylene Glycol) Hydrogel Films as Biosensor Coatings for the Detection of Collagenase. Sensors (Basel) 2019; 19:E1677. [PMID: 30965649 PMCID: PMC6479908 DOI: 10.3390/s19071677] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 12/20/2022]
Abstract
Peptide cross-linked poly(ethylene glycol) hydrogel has been widely used for drug delivery and tissue engineering. However, the use of this material as a biosensor for the detection of collagenase has not been explored. Proteases play a key role in the pathology of diseases such as rheumatoid arthritis and osteoarthritis. The detection of this class of enzyme using the degradable hydrogel film format is promising as a point-of-care device for disease monitoring. In this study, a protease biosensor was developed based on the degradation of a peptide cross-linked poly(ethylene glycol) hydrogel film and demonstrated for the detection of collagenase. The hydrogel was deposited on gold-coated quartz crystals, and their degradation in the presence of collagenase was monitored using a quartz crystal microbalance (QCM). The biosensor was shown to respond to concentrations between 2 and 2000 nM in less than 10 min with a lower detection limit of 2 nM.
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Affiliation(s)
- Norlaily Ahmad
- School of Engineering and Material Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
- Centre of Foundation Studies, Universiti Teknologi MARA, Cawangan Selangor, Kampus Dengkil, Dengkil, Selangor 43800, Malaysia.
| | - Burcu Colak
- School of Engineering and Material Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - De-Wen Zhang
- Institute of Medical Engineering, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China.
| | - Martin John Gibbs
- School of Engineering and Material Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Michael Watkinson
- The Lennard-Jones Laboratories, School of Chemical and Physical Sciences, Keele University, Staffordshire, ST5 5BG, UK.
| | - C Remzi Becer
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
| | - Julien E Gautrot
- School of Engineering and Material Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Steffi Krause
- School of Engineering and Material Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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10
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Abstract
Although metal-ion-binding interlocked molecules have been under intense investigation for over three decades, their application as scaffolds for the development of sensors for metal ions remains underexplored. In this work, we demonstrate the potential of simple rotaxanes as metal-ion-responsive ligand scaffolds through the development of a proof-of-concept selective sensor for Zn2+ .
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Affiliation(s)
- Mathieu Denis
- ChemistryUniversity of SouthamptonHighfieldSouthamptonSO17 1BJUK
| | - Jessica Pancholi
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
| | - Kajally Jobe
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
| | - Michael Watkinson
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSUK
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11
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Affiliation(s)
- Mathieu Denis
- Chemistry; University of Southampton; Highfield Southampton SO17 1BJ UK
| | - Jessica Pancholi
- School of Biological and Chemical Sciences; Queen Mary University of London; Mile End Road London E1 4NS UK
| | - Kajally Jobe
- School of Biological and Chemical Sciences; Queen Mary University of London; Mile End Road London E1 4NS UK
| | - Michael Watkinson
- School of Biological and Chemical Sciences; Queen Mary University of London; Mile End Road London E1 4NS UK
| | - Stephen M. Goldup
- Chemistry; University of Southampton; Highfield Southampton SO17 1BJ UK
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12
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Fang L, Trigiante G, Kousseff CJ, Crespo-Otero R, Philpott MP, Watkinson M. Biotin-tagged fluorescent sensor to visualize ‘mobile’ Zn2+ in cancer cells. Chem Commun (Camb) 2018; 54:9619-9622. [DOI: 10.1039/c8cc05425h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A biotin-tagged fluorescent sensor was developed to image Zn2+ in cancer cells specifically, which showed no entry to normal cells.
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Affiliation(s)
- Le Fang
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
| | - Giuseppe Trigiante
- Centre for Cutaneous Research, Institute of Cell and Molecular Science
- Barts and The London School of Medicine and Dentistry
- Queen Mary University of London
- London E1 2AT
- UK
| | - Christina J. Kousseff
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
| | - Rachel Crespo-Otero
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
| | - Michael P. Philpott
- Centre for Cutaneous Research, Institute of Cell and Molecular Science
- Barts and The London School of Medicine and Dentistry
- Queen Mary University of London
- London E1 2AT
- UK
| | - Michael Watkinson
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
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13
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Nodzewska A, Watkinson M. Remarkable increase in the rate of the catalytic epoxidation of electron deficient styrenes through the addition of Sc(OTf)3 to the MnTMTACN catalyst. Chem Commun (Camb) 2018; 54:1461-1464. [DOI: 10.1039/c7cc09698d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sc(OTf)3 produces a remarkable enhancement in the activity of the MnTMTACN catalyst in the epoxidation of electron deficient styrenes.
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Affiliation(s)
- Aneta Nodzewska
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
| | - Michael Watkinson
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London
- UK
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14
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Mehdi H, Gong W, Guo H, Watkinson M, Ma H, Wajahat A, Ning G. Cover Feature: Aggregation-Induced Emission (AIE) Fluorophore Exhibits a Highly Ratiometric Fluorescent Response to Zn 2+
in vitro and in Human Liver Cancer Cells (Chem. Eur. J. 53/2017). Chemistry 2017. [DOI: 10.1002/chem.201703192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hassan Mehdi
- State Key Laboratory of Fine Chemicals; School of Chemical Engineering Dalian University of Technology; Dalian 610023 P. R. China
| | - Weitao Gong
- State Key Laboratory of Fine Chemicals; School of Chemical Engineering Dalian University of Technology; Dalian 610023 P. R. China
| | - Huimin Guo
- School of Chemistry; Dalian University of Technology; Dalian 610023 P. R. China
| | - Michael Watkinson
- The Joseph Priestley Building; School of Biological and Chemical Sciences; Queen Mary University of London; Mile End Road London E1 4NS UK
| | - Hua Ma
- School of Chemistry; Dalian University of Technology; Dalian 610023 P. R. China
| | - Ali Wajahat
- State Key Laboratory of Fine Chemicals; School of Chemical Engineering Dalian University of Technology; Dalian 610023 P. R. China
| | - Guiling Ning
- State Key Laboratory of Fine Chemicals; School of Chemical Engineering Dalian University of Technology; Dalian 610023 P. R. China
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15
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Mehdi H, Gong W, Guo H, Watkinson M, Ma H, Wajahat A, Ning G. Aggregation-Induced Emission (AIE) Fluorophore Exhibits a Highly Ratiometric Fluorescent Response to Zn 2+ in vitro and in Human Liver Cancer Cells. Chemistry 2017; 23:13067-13075. [PMID: 28612518 DOI: 10.1002/chem.201701948] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Indexed: 12/15/2022]
Abstract
Two novel organic fluorophores, containing bis-naphthylamide and quinoline motifs, have been designed and synthesized. One of the fluorophores contains an isobutylene unit and exhibits a significant aggregation-induced emission (AIE) and a remarkable highly selective ratiometric fluorescence response towards Zn2+ in solution as well as in human liver cancer cells. The AIE behavior of this fluorophore was fully verified by fluorescence and UV/Vis spectroscopy, quantum yield calculations, and single-crystal X-ray diffraction, which revealed an intricate crystal packing system. Conversely, a fluorophore that lacks the isobutylene moiety did not exhibit any significant fluorescent properties as a result of its more flexible molecular structure that presumably allows free intramolecular rotational processes to occur.
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Affiliation(s)
- Hassan Mehdi
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering Dalian University of Technology, Dalian, 610023, P. R. China
| | - Weitao Gong
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering Dalian University of Technology, Dalian, 610023, P. R. China
| | - Huimin Guo
- School of Chemistry, Dalian University of Technology, Dalian, 610023, P. R. China
| | - Michael Watkinson
- The Joseph Priestley Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Hua Ma
- School of Chemistry, Dalian University of Technology, Dalian, 610023, P. R. China
| | - Ali Wajahat
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering Dalian University of Technology, Dalian, 610023, P. R. China
| | - Guiling Ning
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering Dalian University of Technology, Dalian, 610023, P. R. China
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16
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Wu F, Zhang DW, Wang J, Watkinson M, Krause S. Copper Contamination of Self-Assembled Organic Monolayer Modified Silicon Surfaces Following a "Click" Reaction Characterized with LAPS and SPIM. Langmuir 2017; 33:3170-3177. [PMID: 28285531 DOI: 10.1021/acs.langmuir.6b03831] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction combined with microcontact printing was used successfully to pattern alkyne-terminated self-assembled organic monolayer-modified silicon surfaces. Despite the absence of a copper peak in X-ray photoelectron spectra, copper contamination was found and visualized using light-addressable potentiometric sensors (LAPS) and scanning photo-induced impedance microscopy (SPIM) after the "click"-modified silicon surfaces were rinsed with hydrochloric acid (HCl) solution, which was frequently used to remove copper residues in the past. Even cleaning with an ethylenediaminetetraacetic acid (EDTA) solution did not remove the copper residue completely. Different strategies for avoiding copper contamination, including the use of bulky chelators for the copper(I) catalyst and rinsing with different reagents, were tested. Only cleaning of the silicon surfaces with an EDTA solution containing trifluoroacetic acid (TFA) after the click modification proved to be an effective method as confirmed by LAPS and SPIM results, which showed the expected potential shift due to the surface charge introduced by functional groups in the monolayer and allowed, for the first time, imaging the impedance of an organic monolayer.
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Affiliation(s)
| | - De-Wen Zhang
- Institute of Materials, China Academy of Engineering Physics , Jiangyou 621908, Sichuan, P.R. China
| | - Jian Wang
- Institute of Medical Engineering, School of Basic Medical Science, Xi'an Jiaotong University Health Science Center , Xi'an 710061, P.R. China
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17
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Johnston NR, Mitchell RK, Haythorne E, Pessoa MP, Semplici F, Ferrer J, Piemonti L, Marchetti P, Bugliani M, Bosco D, Berishvili E, Duncanson P, Watkinson M, Broichhagen J, Trauner D, Rutter GA, Hodson DJ. Beta Cell Hubs Dictate Pancreatic Islet Responses to Glucose. Cell Metab 2016; 24:389-401. [PMID: 27452146 PMCID: PMC5031557 DOI: 10.1016/j.cmet.2016.06.020] [Citation(s) in RCA: 304] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 05/17/2016] [Accepted: 06/23/2016] [Indexed: 12/02/2022]
Abstract
The arrangement of β cells within islets of Langerhans is critical for insulin release through the generation of rhythmic activity. A privileged role for individual β cells in orchestrating these responses has long been suspected, but not directly demonstrated. We show here that the β cell population in situ is operationally heterogeneous. Mapping of islet functional architecture revealed the presence of hub cells with pacemaker properties, which remain stable over recording periods of 2 to 3 hr. Using a dual optogenetic/photopharmacological strategy, silencing of hubs abolished coordinated islet responses to glucose, whereas specific stimulation restored communication patterns. Hubs were metabolically adapted and targeted by both pro-inflammatory and glucolipotoxic insults to induce widespread β cell dysfunction. Thus, the islet is wired by hubs, whose failure may contribute to type 2 diabetes mellitus.
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Affiliation(s)
- Natalie R Johnston
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Ryan K Mitchell
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Elizabeth Haythorne
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Maria Paiva Pessoa
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Francesca Semplici
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Jorge Ferrer
- Beta Cell Genome Regulation Lab, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Lorenzo Piemonti
- Diabetes Research Institute (HSR-DRI), San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, Islet Cell Laboratory, University of Pisa, 56126 Pisa, Italy
| | - Marco Bugliani
- Department of Clinical and Experimental Medicine, Islet Cell Laboratory, University of Pisa, 56126 Pisa, Italy
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland
| | - Ekaterine Berishvili
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, 1205 Geneva, Switzerland
| | - Philip Duncanson
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Michael Watkinson
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Johannes Broichhagen
- Department of Chemistry, Ludwig-Maximilians-Universität München, and Munich Center for Integrated Protein Science, Butenandtstrasse 5-13, 81377 München, Germany
| | - Dirk Trauner
- Department of Chemistry, Ludwig-Maximilians-Universität München, and Munich Center for Integrated Protein Science, Butenandtstrasse 5-13, 81377 München, Germany
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK.
| | - David J Hodson
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, UK; Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, UK.
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18
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Wang J, Campos I, Wu F, Zhu J, Sukhorukov GB, Palma M, Watkinson M, Krause S. The effect of gold nanoparticles on the impedance of microcapsules visualized by scanning photo-induced impedance microscopy. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.05.017] [Citation(s) in RCA: 10] [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] [Indexed: 10/21/2022]
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19
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Jorge AR, Chernobryva M, Rigby SEJ, Watkinson M, Resmini M. Incorporation of Cobalt-Cyclen Complexes into Templated Nanogels Results in Enhanced Activity. Chemistry 2015; 22:3764-74. [PMID: 26661923 PMCID: PMC4797703 DOI: 10.1002/chem.201503946] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 10/01/2015] [Indexed: 11/05/2022]
Abstract
Recent advances in nanomaterials have identified nanogels as an excellent matrix for novel biomimetic catalysts using the molecular imprinting approach. Polymerisable Co‐cyclen complexes with phosphonate and carbonate templates have been prepared, fully characterised and used to obtain nanogels that show high activity and turnover with low catalytic load, compared to the free complex, in the hydrolysis of 4‐nitrophenyl phosphate, a nerve agent simulant. This work demonstrates that the chemical structure of the template has an impact on the coordination geometry and oxidation state of the metal centre in the polymerisable complex resulting in very significant changes in the catalytic properties of the polymeric matrix. Both pseudo‐octahedral cobalt(III) and trigonal‐bipyramidal cobalt(II) structures have been used for the synthesis of imprinted nanogels, and the catalytic data demonstrate that: i) the imprinted nanogels can be used in 15 % load and show turnover; ii) the structural differences in the polymeric matrices resulting from the imprinting approach with different templates are responsible for the molecular recognition capabilities and the catalytic activity. Nanogel P1, imprinted with the carbonate template, shows >50 % higher catalytic activity than P2 imprinted with the phosphonate.
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Affiliation(s)
- Ana Rita Jorge
- Department of Chemistry and Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Mariya Chernobryva
- Department of Chemistry and Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Stephen E J Rigby
- Faculty of Life Sciences, Manchester Institute of Biotechnology, 131 Princess Street, Manchester, M1 7DN, UK
| | - Michael Watkinson
- Department of Chemistry and Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Marina Resmini
- Department of Chemistry and Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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20
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Wang J, Wu F, Watkinson M, Zhu J, Krause S. "Click" Patterning of Self-Assembled Monolayers on Hydrogen-Terminated Silicon Surfaces and Their Characterization Using Light-Addressable Potentiometric Sensors. Langmuir 2015; 31:9646-9654. [PMID: 26274063 DOI: 10.1021/acs.langmuir.5b02069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Two potential strategies for chemically patterning alkyne-terminated self-assembled monolayers (SAMs) on oxide-free silicon or silicon-on-sapphire (SOS) substrates were investigated and compared. The patterned surfaces were validated using a light-addressable potentiometric sensor (LAPS) for the first time. The first strategy involved an integration of photolithography with "click" chemistry. Detailed surface characterization (i.e. water contact angle, ellipsometry, AFM, and XPS) and LAPS measurements showed that photoresist processing not only decreases the coverage of organic monolayers but also introduces chemically bonded contaminants on the surfaces, thus significantly reducing the quality of the SAMs and the utility of "click" surface modification. The formation of chemical contaminants in photolithography was also observed on carboxylic acid- and alkyl-terminated monolayers using LAPS. In contrast, a second approach combined microcontact printing (μCP) with "click" chemistry; that is azide (azido-oligo(ethylene glycol) (OEG)-NH2) inks were printed on alkyne-terminated SAMs on silicon or SOS through PDMS stamps. The surface characterization results for the sample printed with a flat featureless PDMS stamp demonstrated a nondestructive and efficient method of μCP to perform "click" reactions on alkyne-terminated, oxide-free silicon surfaces for the first time. For the sample printed with a featured PDMS stamp, LAPS imaging showed a good agreement with the pattern of the PDMS stamp, indicating the successful chemical patterning on non-oxidized silicon and SOS substrates and the capability of LAPS to image the molecular patterns with high sensitivity.
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Affiliation(s)
- Jian Wang
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Fan Wu
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Michael Watkinson
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Jingyuan Zhu
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
| | - Steffi Krause
- School of Engineering and Materials Science and ‡School of Biological and Chemical Sciences, Queen Mary University of London , Mile End Road, London E1 4NS, U.K
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21
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Biela A, Watkinson M, Meier UC, Baker D, Giovannoni G, Becer CR, Krause S. Disposable MMP-9 sensor based on the degradation of peptide cross-linked hydrogel films using electrochemical impedance spectroscopy. Biosens Bioelectron 2015; 68:660-667. [PMID: 25660510 DOI: 10.1016/j.bios.2015.01.060] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/23/2015] [Accepted: 01/26/2015] [Indexed: 11/17/2022]
Abstract
Matrix metalloproteinase-9 (MMP-9) plays an important role in both physiological and pathological processes. This enzyme is a peripheral biomarker of neuroinflammation in multiple sclerosis (MS), a chronic autoimmune disease of the central nervous system. Presently, expensive magnetic resonance imaging (MRI) studies are used to monitor subclinical disease activity in MS. An alternative to costly MRI scans could be the detection of MMP-9, using a low-cost, disposable sensor system for MMP-9 suitable for home-monitoring of inflammation. This would allow an early prediction of the failure of anti-inflammatory therapies and more timely clinical intervention to limit neuronal damage and prevent disability. Herein we present the development of a disposable sensor for fast and straightforward detection of MMP-9. Biosensors were produced by coating electrodes with oxidized dextran and subsequent cross-linking with peptides containing specific cleavage sites for MMP-9. Exposure of the films to the enzyme resulted in the degradation of the films, which was monitored using impedance measurements. Sensor response was rapid, a significant impedance change was usually observed within 5 min after the addition of MMP-9. Sensors showed a negligible response to matrix metalloproteinase-2 (MMP-2), a protease which may interfere with MMP-9 detection. The peptide sequence with the highest sensitivity and selectivity Leu-Gly-Arg-Met-Gly-Leu-Pro-Gly-Lys was selected to construct calibration curves. MMP-9 was successfully detected in a clinically relevant range from 50 to 400 ng/ml. Two different processes of hydrogel degradation were observed on electrode surfaces with different roughness, and both appeared suitable to monitor MMP-9 activity. The sensor materials are generic and can be easily adopted to respond to other proteases by selecting peptide cross-linkers with suitable cleavage sites.
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Affiliation(s)
- Anna Biela
- School of Engineering and Materials Science, Queen Mary University of London, UK
| | - Michael Watkinson
- School of Biological and Chemical Sciences, Queen Mary University of London, UK
| | - Ute C Meier
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - David Baker
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Gavin Giovannoni
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - C Remzi Becer
- School of Engineering and Materials Science, Queen Mary University of London, UK
| | - Steffi Krause
- School of Engineering and Materials Science, Queen Mary University of London, UK.
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22
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Pancholi J, Hodson DJ, Jobe K, Rutter GA, Goldup SM, Watkinson M. Biologically targeted probes for Zn 2+: a diversity oriented modular "click-S NAr-click" approach†Electronic supplementary information (ESI) available: Full experimental details including characterisation of all novel compounds can be found in the ESI. See DOI: 10.1039/c4sc01249f. Chem Sci 2014; 5:3528-3535. [PMID: 25580213 PMCID: PMC4285101 DOI: 10.1039/c4sc01249f] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [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: 04/30/2014] [Accepted: 05/26/2014] [Indexed: 12/29/2022] Open
Abstract
We describe a one-pot strategy for the high yielding, operationally simple synthesis of fluorescent probes for Zn2+ that bear biological targeting groups and exemplify the utility of our method through the preparation of a small library of sensors. Investigation of the fluorescence behaviour of our library revealed that although all behaved as expected in MeCN, under biologically relevant conditions in HEPES buffer, a plasma membrane targeting sensor displayed a dramatic switch on response to excess Zn2+ as a result of aggregation phenomena. Excitingly, in cellulo studies in mouse pancreatic islets demonstrated that this readily available sensor was indeed localised to the exterior of the plasma membrane and clearly responded to the Zn2+ co-released when the pancreatic beta cells were stimulated to release insulin. Conversely, sensors that target intracellular compartments were unaffected. These results demonstrate that this sensor has the potential to allow the real time study of insulin release from living cells and exemplifies the utility of our simple synthetic approach.
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Affiliation(s)
- J Pancholi
- School of Biological and Chemical Science , Queen Mary University of London , Mile End Road , London , E1 4NS , UK . ;
| | - D J Hodson
- Section of Cell Biology , Division of Diabetes , Endocrinology and Metabolism , Department of Medicine , Imperial College London , London , W12 0NN , UK .
| | - K Jobe
- School of Biological and Chemical Science , Queen Mary University of London , Mile End Road , London , E1 4NS , UK . ;
| | - G A Rutter
- Section of Cell Biology , Division of Diabetes , Endocrinology and Metabolism , Department of Medicine , Imperial College London , London , W12 0NN , UK .
| | - S M Goldup
- School of Biological and Chemical Science , Queen Mary University of London , Mile End Road , London , E1 4NS , UK . ;
| | - M Watkinson
- School of Biological and Chemical Science , Queen Mary University of London , Mile End Road , London , E1 4NS , UK . ;
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Wong HS, Santhakumaran S, Statnikov Y, Gray D, Watkinson M, Modi N. Retinopathy of prematurity in English neonatal units: a national population-based analysis using NHS operational data. Arch Dis Child Fetal Neonatal Ed 2014; 99:F196-202. [PMID: 24361602 DOI: 10.1136/archdischild-2013-304508] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To report on retinopathy of prematurity (ROP) screening compliance against a national guideline, factors associated with non-compliance and effect on ROP treatment. DESIGN National cohort study using operational NHS data from the National Neonatal Research Database (NNRD) for the period 2009-2011. SETTING 161 (94%) neonatal units in England. POPULATION Infants born below 32 weeks' gestation and/or with a birth weight below 1501 g. MAIN OUTCOME MEASURES ROP screening status ('on-time', 'early', 'late', 'unknown') and associated infant and neonatal unit characteristics, ROP treatment. RESULTS The proportion of infants screened on-time increased over the study period (p<0.001). Of 19 821 eligible infants, 7602 (38.4%) were recorded to have received ROP screening in accordance with the national guideline; 7474 (37.8%) received screening outside the recommended time period; data were missing for 4745 (16.7%) infants. For 16 411 infants in neonatal care during the recommended screening period, late screening was significantly associated with lower gestational age (relative risk ratio (RRR) (95% credible interval) for late versus on-time screening 0.83 (0.80 to 0.86) for each increased week of gestation) and care in a neonatal unit providing less than 500 days of intensive care per annum (2.48 (0.99 to 4.99)). Infants screened late were almost 40% more likely to receive ROP treatment (OR (95% CI) 1.36 (1.05 to 1.76)). CONCLUSIONS Understanding organisational differences between neonatal units may help improve ROP screening. Patient-level electronic NHS clinical data offer opportunity for future rapid, low cost, population-based evaluations but require improved data entry.
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Affiliation(s)
- Hilary S Wong
- Neonatal Data Analysis Unit, Section of Neonatal Medicine, Department of Medicine, Imperial College London, , London, UK
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24
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Ilyashenko G, De Faveri G, Follier T, Al-Safadi R, Motevalli M, Watkinson M. Catalytic and mechanistic studies into the epoxidation of styrenes using manganese complexes of structurally similar polyamine ligands. Org Biomol Chem 2014; 12:1124-34. [DOI: 10.1039/c3ob42274g] [Citation(s) in RCA: 10] [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: 01/30/2023]
Abstract
The synthesis and catalytic activity of manganese(ii) complexes of two polyamine ligands is reported which highlights how a small structural change in the ligand affects the overall catalytic behaviour.
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Affiliation(s)
- Gennadiy Ilyashenko
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London, UK
| | - Giorgio De Faveri
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London, UK
| | - Thomas Follier
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London, UK
| | - Rawan Al-Safadi
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London, UK
| | - Majid Motevalli
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London, UK
| | - Michael Watkinson
- The Joseph Priestley Building
- School of Biological and Chemical Sciences
- Queen Mary University of London
- London, UK
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25
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Ilyashenko G, De Faveri G, Masoudi S, Al-Safadi R, Watkinson M. Initial rate kinetic studies show an unexpected influence of para-substituents on the catalytic behaviour of manganese complexes of TMTACN in the epoxidation of styrenes with H2O2. Org Biomol Chem 2013; 11:1942-51. [PMID: 23358659 DOI: 10.1039/c3ob27217f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Investigations into the efficacy of a range of enantiomerically pure BINOL additives in the epoxidation of styrene substrates with a number of manganese catalysts prepared from the ligand 1,4,7-trimethyl-1,4,7-triazacyclononane, TMTACN, using hydrogen peroxide as the oxidant have revealed that there are fundamental differences in reactivity between apparently similar systems. Whilst no asymmetric induction was obtained in the styrene oxide products formed, the data obtained from initial rate kinetic studies appear to be consistent with a number of different catalytically active species operating, the nature of which are profoundly affected by the starting materials used.
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Affiliation(s)
- Gennadiy Ilyashenko
- The Joseph Priestley Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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26
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Ilyashenko G, Al-Safadi R, Donnan R, Dubrovka R, Pancholi J, Watkinson M, Whiting A. A synthesis of a 1,1′-desymmetrised ferrocene backbone and its facile one-pot double-“click” functionalisation. RSC Adv 2013. [DOI: 10.1039/c3ra43054e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Abstract
Terahertz spectroscopy is only now beginning to make its transition from initial development by physicists and engineers to broader use by chemists, materials scientists and biologists, thanks to the increasing availability of commercial terahertz spectrometers. With the unique insights that terahertz spectroscopy can provide into intermolecular bonding and crystalline matter, it could prove to be an invaluable addition to the chemist's analytical toolset. This tutorial review aims to give an introduction to terahertz spectroscopy, its techniques, equipment, current applications and potential for the chemical sciences to a broad readership.
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Affiliation(s)
- Alexander I McIntosh
- Queen Mary University of London, School of Electrical Engineering & Computer Science, Mile End Road, London, E1 4NS, UK
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28
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Lahlali H, Jobe K, Watkinson M, Goldup SM. Macrocycle size matters: "small" functionalized rotaxanes in excellent yield using the CuAAC active template approach. Angew Chem Int Ed Engl 2011; 50:4151-5. [PMID: 21462287 DOI: 10.1002/anie.201100415] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Hicham Lahlali
- School of Biological and Chemical Sciences, Queen Mary University of London, Joseph Priestley Building, Mile End Road, London, E1 4NS, UK
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29
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Lahlali H, Jobe K, Watkinson M, Goldup SM. Macrocycle Size Matters: “Small” Functionalized Rotaxanes in Excellent Yield Using the CuAAC Active Template Approach. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201100415] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Zheng X, Cook JP, Watkinson M, Yang S, Douglas I, Rawlinson A, Krause S. Generic protease detection technology for monitoring periodontal disease. Faraday Discuss 2011; 149:37-47; discussion 63-77. [DOI: 10.1039/c005364c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [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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32
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Jobe K, Brennan CH, Motevalli M, Goldup SM, Watkinson M. Modular ‘click’ sensors for zinc and their application in vivo. Chem Commun (Camb) 2011; 47:6036-8. [DOI: 10.1039/c1cc11213a] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [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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33
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De Faveri G, Ilyashenko G, Watkinson M. Recent advances in catalytic asymmetric epoxidation using the environmentally benign oxidant hydrogen peroxide and its derivatives. Chem Soc Rev 2010; 40:1722-60. [PMID: 21079863 DOI: 10.1039/c0cs00077a] [Citation(s) in RCA: 270] [Impact Index Per Article: 19.3] [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
There has been a recent drive to develop asymmetric catalytic methods to produce epoxides using environmentally benign oxidants, especially hydrogen peroxide. This critical review discusses the advances that have been made using both metal-based and organocatalytic homogeneous catalysts (142 references).
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Affiliation(s)
- Giorgio De Faveri
- The Joseph Priestly Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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34
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Affiliation(s)
- Sonia Pulacchini
- a Department of Chemistry, Queen Mary , University of London , Mile End Road, London , E1 4NS , UK
| | - Isaac Abrahams
- a Department of Chemistry, Queen Mary , University of London , Mile End Road, London , E1 4NS , UK
| | - Jason Eames
- a Department of Chemistry, Queen Mary , University of London , Mile End Road, London , E1 4NS , UK
| | - Michael Watkinson
- a Department of Chemistry, Queen Mary , University of London , Mile End Road, London , E1 4NS , UK
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35
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Tamanini E, Flavin K, Motevalli M, Piperno S, Gheber LA, Todd MH, Watkinson M. Cyclam-Based “Clickates”: Homogeneous and Heterogeneous Fluorescent Sensors for Zn(II). Inorg Chem 2010; 49:3789-800. [DOI: 10.1021/ic901939x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Emiliano Tamanini
- The Joseph Priestly Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, U.K
| | - Kevin Flavin
- The Joseph Priestly Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, U.K
| | - Majid Motevalli
- The Joseph Priestly Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, U.K
| | - Silvia Piperno
- Department of Biotechnological Engineering, Ben Gurion University Negev, IL-84105 Beer Sheva, Israel
| | - Levi A. Gheber
- Department of Biotechnological Engineering, Ben Gurion University Negev, IL-84105 Beer Sheva, Israel
| | - Matthew H. Todd
- School of Chemistry, University of Sydney, NSW 2006, Australia
| | - Michael Watkinson
- The Joseph Priestly Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, U.K
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36
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Sheriff TS, Watkinson M, Motevalli M, Lesin JF. Unexpected formation of a novel pyridinium-containing catecholate ligand and its manganese(iii) complex. Dalton Trans 2010:53-5. [DOI: 10.1039/b915747f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [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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Singh A, Duckett J, Newton T, Watkinson M. Improving neonatal unit admission temperatures in preterm babies: exothermic mattresses, polythene bags or a traditional approach? J Perinatol 2010; 30:45-9. [PMID: 19641512 DOI: 10.1038/jp.2009.94] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To investigate whether exothermic sodium acetate mattresses were associated with an improvement in the thermal care of babies <30 weeks gestation between birth and admission to a neonatal unit. STUDY DESIGN Analysis of a three case series of babies: the first with traditional thermal care of drying and wrapping in a towel, the second with wrapping in food standard polythene bags and the third with wrapping in polythene bags and nursing on an activated exothermic mattress. The main outcome measure was the temperature on admission to the neonatal unit. RESULT There were no significant differences between the groups for gestation and birth weight. Hypothermia was less frequent in the 'bag and mattress' group compared with the 'bag only' and traditional care groups (26 vs 69 vs 84%, respectively) even though the median time to admission was longest in the 'bag and mattress' group (23 min). The proportions of babies admitted with temperatures in the target range of 36.5 to 37.5 degrees C were 46, 27 and 16%, respectively. Multiple regression analysis showed that use of the mattress raised admission temperatures by 1.04 degrees C. The median temperature of babies in the 'bag and mattress' group was higher compared with the other groups (36.9 vs 36.0 vs 35.8 degrees C), but significantly more were hyperthermic (28 vs 4 and 0.4%, respectively). CONCLUSION Use of exothermic mattresses for babies <30 weeks gestation was associated with a significantly greater proportion of babies being admitted to the neonatal unit with a temperature in the euthermic range, but there was also an increased risk of hyperthermia.
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Affiliation(s)
- A Singh
- Neonatal Unit, Birmingham Heartlands Hospital, Birmingham, UK
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Martínez D, Motevalli M, Watkinson M. Is there really a diagnostically useful relationship between the carbon-oxygen stretching frequencies in metal carboxylate complexes and their coordination mode? Dalton Trans 2009:446-55. [PMID: 20023980 DOI: 10.1039/b913865j] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An investigation into the relationship between the asymmetric and symmetric stretching modes of ancillary carboxylate ligands and their mode of binding in a family of manganese(III) complexes of tetradentate N(2)O(2) Schiff base ligands, which includes comparison of an (18)O isotopically labelled derivative, has been undertaken. The results suggest that caution should be employed in using this technique to assign the binding mode of the carboxylate ligands in these complexes despite its very extensive use in the literature.
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Affiliation(s)
- David Martínez
- The Joseph Priestley Building, School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Pawłowski P, Maksymiuk K, Tamanini E, Watkinson M, Michalska A, Hall E. Inducing Sensitivity to Heavy Metal Ions in Polypyrrole Modified by Azamacrocyclic Ligands. ELECTROANAL 2009. [DOI: 10.1002/elan.200904637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Tamanini E, Rigby SE, Motevalli M, Todd M, Watkinson M. Responsive Metal Complexes: A Click-Based “Allosteric Scorpionate” Complex Permits the Detection of a Biological Recognition Event by EPR/ENDOR Spectroscopy. Chemistry 2009; 15:3720-8. [DOI: 10.1002/chem.200802425] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
A cyclam-based macrocyclic sensor has been prepared using synthetically simple "click" chemistry to link a fluorophore to the macrocyclic receptor. This sensor shows high selectivity for Zn(II) over a range of other metals, providing a significant enhancement of fluorescence intensity over a wide pH range. As such, this is the first cyclam-based sensor demonstrated to be selective for Zn(II) and is the first example of a triazole being used as a coordinating ligand on an azamacrocycle. The sensor can access biologically available zinc in mammalian cells, sensing the Zn(II) flux that exists during apoptotic cell death.
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Affiliation(s)
- Emiliano Tamanini
- The Walter Besant Building, School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS, United Kingdom
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Abstract
After being in a relatively stable thermoneutral uterus for the whole of pregnancy, the newborn baby enters a cooling environment and might suffer significant heat loss and hypothermia in the first minutes of life. Alternatively, the fetus might face significant hyperthermia during and immediately after delivery if the mother is febrile. Hypothermia, particularly in preterm babies, is associated with increased morbidity and mortality. Hyperthermic babies have a worse short-term outcome, and hyperthermia can be particularly detrimental in association with intrapartum asphyxia and infection. Prevention and treatment of these variations in temperature are still developing and the efficacy of some strategies remains unclear. Nevertheless, one goal in the delivery room is to maintain the newborn baby's temperature within the physiologically optimum range.
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Affiliation(s)
- Abbot R Laptook
- Neonatal Intensive Care Unit, Women and Infants Hospital of Rhode Island, Rhode Island, USA.
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Abstract
The biotin-(strept)avidin interaction remains a gold standard of model biological recognition events. The biotinylation of azamacrocycles permits the investigation of signal transduction between this recognition event and the metal center of an azamacrocycle complex, of wide potential interest in biosensing. There are no generally applicable procedures in the literature for such functionalizations. We report here a comprehensive investigation into the attachment of biotin to TACN, cyclen, and cyclam. Effective methods have been found for each ring. The efficacy of the functionalization is critically dependent on the nature of the azamacrocycle.
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Affiliation(s)
- Sara J Krivickas
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS, United Kingdom
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Boyle E, Freer Y, Khan-Orakzai Z, Watkinson M, Wright E, Ainsworth J, McIntosh N. Sucrose and non-nutritive sucking for the relief of pain in screening for retinopathy of prematurity: A randomised controlled trial. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.acpain.2006.08.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Ilyashenko G, Motevalli M, Watkinson M. An alternative model for the asymmetric addition of cyanide to aldehydes catalysed by titanium–salen complexes based on a structurally related iron–salen complex. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Watkinson M, Ilyashenko G, Choudhury R, Motevalli M. Concentration-Dependent Chemo- and Regioselective Metalation of 6,6′-Dibromo-2,2′-bipyridine. Synlett 2006. [DOI: 10.1055/s-2006-944192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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47
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Boyle EM, Freer Y, Khan-Orakzai Z, Watkinson M, Wright E, Ainsworth JR, McIntosh N. Sucrose and non-nutritive sucking for the relief of pain in screening for retinopathy of prematurity: a randomised controlled trial. Arch Dis Child Fetal Neonatal Ed 2006; 91:F166-8. [PMID: 16428355 PMCID: PMC2672697 DOI: 10.1136/adc.2005.087668] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Screening is necessary for infants at risk of retinopathy of prematurity. Despite local anaesthetic drops, infants find eye examinations distressing, displaying behavioural and physiological changes indicating acute pain. Oral sucrose and non-nutritive sucking reduce pain responses associated with invasive procedures. OBJECTIVE To evaluate the use of oral sucrose and/or pacifier for reducing pain responses during eye examinations. METHODS Forty infants <32 weeks gestation or <1500 g birth weight, in two neonatal units, were randomised to one of four interventions administered two minutes before their first screening examination: 1 ml sterile water as placebo (group 1, n = 10), 1 ml 33% sucrose solution (group 2, n = 10), 1 ml sterile water with pacifier (group 3, n = 9), or 1 ml 33% sucrose solution with pacifier (group 4, n = 11). Examinations were videotaped. Two observers, blind to the intervention, assessed recordings. Pain responses were scored using the premature infant pain profile (PIPP). RESULTS The groups were similar in gestation, birth weight, and age at examination. Mean PIPP scores were 15.3, 14.3, 12.3, and 12.1 for groups 1, 2, 3, and 4 respectively. Analysis of variance showed a significant difference in PIPP score between groups (p = 0.023). Infants randomised to pacifiers scored lower than those without pacifiers (p = 0.003). There was no difference between groups receiving sucrose and those receiving water (p = 0.321). CONCLUSIONS Non-nutritive sucking reduced distress responses in infants undergoing screening for retinopathy of prematurity. The difference in response was large enough to be detected by a validated assessment tool. No synergistic effect of sucrose and pacifier was apparent in this group.
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Affiliation(s)
- E M Boyle
- University Medical Centre, Department of Pediatrics, Room 4G40, 1200 Main Street West, Hamilton, Ontario L8S 4J9, Canada.
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Abstract
The body temperature of preterm babies can drop precipitously after delivery, and this hypothermia is associated with an increase in mortality and morbidity. Reports of hypothermia in babies of all birth weights, on admission to neonatal units, have come from all over the world; most also report increased mortality in association with hypothermia. Recent reports that showed that hypothermia on admission to neonatal units is an independent risk factor for mortality in preterm babies have refocused attention on the need for meticulous thermal care immediately after birth and during resuscitation. Their data lend weight to the view that conventional approaches to thermal care of the very preterm and low birth weight baby are outmoded.
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Sibbons KF, Shastri K, Watkinson M. The application of manganese complexes of ligands derived from 1,4,7-triazacyclononane in oxidative catalysis. Dalton Trans 2006:645-61. [PMID: 16429167 DOI: 10.1039/b511331h] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Since the disclosure that manganese complexes of certain azamacrocyclic ligands were potent low-temperature bleaching catalysts, considerable effort has focussed on their development towards the efficient catalytic oxidation of other substrates, principally with the environmentally benign oxidant H(2)O(2). These efforts have resulted in a broad substrate scope for the system, including alkenes (to give both epoxides and cis-diols as potential products), alcohols, sulfides and C-H oxidation. Additional developments include the heterogenisation of catalytic systems as well as the first generation of enantiomerically pure ligand systems for application in asymmetric epoxidation catalysis. To date there has only been modest success in this regard, but as our understanding of the nature of the active oxidant(s) continues to develop it is likely that there will be viable applications for these systems in the near future.
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Affiliation(s)
- Kevin F Sibbons
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
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Coumbarides GS, Eames J, Scheuermann JEW, Sibbons KF, Suggate MJ, Watkinson M. Enantioselective Protonation of a Lithium Enolate Derived from 2-Methyl-1-tetralone Using Chiral Sulfonamides. BCSJ 2005. [DOI: 10.1246/bcsj.78.906] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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