1
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Khaled YS, Khot MI, Aiyappa-Maudsley R, Maisey T, Pramanik A, Tiernan J, Lintern N, Al-Enezi E, Shamsuddin SH, Tomlinson D, Coletta L, Millner PA, Hughes TA, Jayne DG. Photoactive imaging and therapy for colorectal cancer using a CEA-Affimer conjugated Foslip nanoparticle. Nanoscale 2024; 16:7185-7199. [PMID: 38506227 PMCID: PMC10993305 DOI: 10.1039/d3nr04118b] [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] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/08/2023] [Indexed: 03/21/2024]
Abstract
Theranostic nanoparticles hold promise for simultaneous imaging and therapy in colorectal cancer. Carcinoembryonic antigen can be used as a target for these nanoparticles because it is overexpressed in most colorectal cancers. Affimer reagents are synthetic proteins capable of binding specific targets, with additional advantages over antibodies for targeting. We fabricated silica nanoparticles using a water-in-oil microemulsion technique, loaded them with the photosensitiser Foslip, and functionalised the surface with anti-CEA Affimers to facilitate fluorescence imaging and photodynamic therapy of colorectal cancer. CEA-specific fluorescence imaging and phototoxicity were quantified in colorectal cancer cell lines and a LS174T murine xenograft colorectal cancer model. Anti-CEA targeted nanoparticles exhibited CEA-specific fluorescence in the LoVo, LS174T and HCT116 cell lines when compared to control particles (p < 0.0001). No toxicity was observed in LS174T cancer mouse xenografts or other organs. Following photo-irradiation, the anti-CEA targeted particles caused significant cell death in LoVo (60%), LS174T (90%) and HCT116 (70%) compared to controls (p < 0.0001). Photodynamic therapy (PDT) at 24 h in vivo showed a 4-fold reduction in tumour volume compared to control mouse xenografts (p < 0.0001). This study demonstrates the efficacy of targeted fluorescence imaging and PDT using Foslip nanoparticles conjugated to anti-CEA Affimer nanoparticles in in vitro and in vivo colorectal cancer models.
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Affiliation(s)
- Yazan S Khaled
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
| | - M Ibrahim Khot
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
| | | | - Thomas Maisey
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
| | - Arindam Pramanik
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
| | - Jim Tiernan
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
| | - Nicole Lintern
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Eiman Al-Enezi
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Shazana H Shamsuddin
- Department of Pathology, School of Medical Sciences, University Sains Malaysia, Malaysia
| | - Darren Tomlinson
- School of Molecular and Cellular Biology, University of Leeds, Leeds, UK
| | - Louise Coletta
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
| | - Paul A Millner
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Thomas A Hughes
- School of Medicine, University of Leeds, Leeds, UK
- School of Science, Technology and Health, York St John University, York, UK
| | - David G Jayne
- Leeds Institute of Medical Research, St James's University Hospital, Leeds, United Kingdom.
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2
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Pramanik A, Xu Z, Ingram N, Coletta PL, Millner PA, Tyler AII, Hughes TA. Hyaluronic-Acid-Tagged Cubosomes Deliver Cytotoxics Specifically to CD44-Positive Cancer Cells. Mol Pharm 2022; 19:4601-4611. [PMID: 35938983 PMCID: PMC9727730 DOI: 10.1021/acs.molpharmaceut.2c00439] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Delivery of chemotherapy drugs specifically to cancer cells raises local drug doses in tumors and therefore kills more cancer cells while reducing side effects in other tissues, thereby improving oncological and quality of life outcomes. Cubosomes, liquid crystalline lipid nanoparticles, are potential vehicles for delivery of chemotherapy drugs, presenting the advantages of biocompatibility, stable encapsulation, and high drug loading of hydrophobic or hydrophilic drugs. However, active targeting of drug-loaded cubosomes to cancer cells, as opposed to passive accumulation, remains relatively underexplored. We formulated and characterized cubosomes loaded with potential cancer drug copper acetylacetonate and functionalized their surfaces using click chemistry coupling with hyaluronic acid (HA), the ligand for the cell surface receptor CD44. CD44 is overexpressed in many cancer types including breast and colorectal. HA-tagged, copper-acetylacetonate-loaded cubosomes have an average hydrodynamic diameter of 152 nm, with an internal nanostructure based on the space group Im3m. These cubosomes were efficiently taken up by two CD44-expressing cancer cell lines (MDA-MB-231 and HT29, representing breast and colon cancer) but not by two CD44-negative cell lines (MCF-7 breast cancer and HEK-293 kidney cells). HA-tagged cubosomes caused significantly more cell death than untargeted cubosomes in the CD44-positive cells, demonstrating the value of the targeting. CD44-negative cells were equally relatively resistant to both, demonstrating the specificity of the targeting. Cell death was characterized as apoptotic. Specific targeting and cell death were evident in both 2D culture and 3D spheroids. We conclude that HA-tagged, copper-acetylacetonate-loaded cubosomes show great potential as an effective therapeutic for selective targeting of CD44-expressing tumors.
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Affiliation(s)
- Arindam Pramanik
- School
of Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom,
| | - Zexi Xu
- School
of Food Science and Nutrition, University
of Leeds, Leeds LS2 9JT, United Kingdom
| | - Nicola Ingram
- School
of Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Paul A Millner
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Arwen I I Tyler
- School
of Food Science and Nutrition, University
of Leeds, Leeds LS2 9JT, United Kingdom,
| | - Thomas A Hughes
- School
of Medicine, University of Leeds, Leeds LS2 9JT, United Kingdom,
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3
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Nampi PP, Vakurov A, Saha S, Jose G, Millner PA. Surface modified hexagonal upconversion nanoparticles for the development of competitive assay for biodetection. Biomater Adv 2022; 136:212763. [PMID: 35929306 DOI: 10.1016/j.bioadv.2022.212763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/03/2022] [Accepted: 03/13/2022] [Indexed: 06/15/2023]
Abstract
Up-conversion nanoparticles (UCNPs) of sodium yttrium fluoride with ytterbium and erbium ions as sensitizer and activator (β-NaYF4/Yb3+/Er3+) have been synthesised by a solvothermal method. The synthesised particles were found to be highly uniform in size (~50 nm) and of hexagonal crystal phase producing strong up-conversion luminescence dominated in the green wavelength region. During the synthesis, photoluminescence properties of the reaction mixture were monitored at regular intervals to ensure the required particle size distribution and luminescence efficiency. The hydrophobic particles thus obtained were modified by coating with silica, yielding particles that were stable in aqueous media. The silica coated UCNPs were further modified with maleimide-polyethylene glycol-silane (mal-PEG-silane) to provide thiol reactive surface groups. The silanized, maleimide-bearing UCNPs were effective for conjugating to reductively-cleaved half antibodies against ofloxacin, a veterinary antibiotic, to produce photoluminescent nanobiosensors for its detection and quantification. The speed and minimum detection concentration (~10 nM) that we report for a competitive assay of ofloxacin in this study is promising for developing sensors for this and other biomolecules.
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Affiliation(s)
- Padmaja Parameswaran Nampi
- School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom; Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Alexander Vakurov
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sikha Saha
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Gin Jose
- School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Paul A Millner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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4
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Pramanik A, Xu Z, Shamsuddin SH, Khaled YS, Ingram N, Maisey T, Tomlinson D, Coletta PL, Jayne D, Hughes TA, Tyler AII, Millner PA. Affimer Tagged Cubosomes: Targeting of Carcinoembryonic Antigen Expressing Colorectal Cancer Cells Using In Vitro and In Vivo Models. ACS Appl Mater Interfaces 2022; 14:11078-11091. [PMID: 35196008 PMCID: PMC9007418 DOI: 10.1021/acsami.1c21655] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/17/2022] [Indexed: 05/10/2023]
Abstract
Nanomedicines, while having been approved for cancer therapy, present many challenges such as low stability, rapid clearance, and nonspecificity leading to off-target toxicity. Cubosomes are porous lyotropic liquid crystalline nanoparticles that have shown great premise as drug delivery vehicles; however, their behavior in vivo is largely underexplored, hindering clinical translation. Here, we have engineered cubosomes based on the space group Im3m that are loaded with copper acetylacetonate as a model drug, and their surfaces are functionalized for the first time with Affimer proteins via copper-free click chemistry to actively target overexpressed carcinoembryonic antigens on LS174T colorectal cancer cells. Unlike nontargeted cubosomes, Affimer tagged cubosomes showed preferential accumulation in cancer cells compared to normal cells not only in vitro (2D monolayer cell culture and 3D spheroid models) but also in vivo in colorectal cancer mouse xenografts, while exhibiting low nonspecific absorption and toxicity in other vital organs. Cancerous spheroids had maximum cell death compared to noncancerous cells upon targeted delivery. Xenografts subjected to targeted drug-loaded cubosomes showed a 5-7-fold higher drug accumulation in the tumor tissue compared to the liver, kidneys, and other vital organs, a significant decrease in tumor growth, and an increased survival rate compared to the nontargeted group. This work encompasses the first thorough preclinical investigation of Affimer targeted cubosomes as a cancer therapeutic.
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Affiliation(s)
- Arindam Pramanik
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
- School
of Medicine, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Zexi Xu
- School
of Food Science and Nutrition, University
of Leeds, Leeds LS2 9JT, United Kingdom
- School
of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Shazana H. Shamsuddin
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
- Department
of Pathology, School of Medical Sciences, Universiti Sains Malaysia, George Town 16150, Malaysia
| | - Yazan S. Khaled
- School
of Medicine, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Nicola Ingram
- Leeds Institute
of Medical Research, St James’s University
Hospital, Leeds LS9 7TF, United Kingdom
| | - Thomas Maisey
- School
of Medicine, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Darren Tomlinson
- Biomedical
Health Research Centre, BioScreening Technology Group, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - P. Louise Coletta
- Leeds Institute
of Medical Research, St James’s University
Hospital, Leeds LS9 7TF, United Kingdom
| | - David Jayne
- Leeds Institute
of Medical Research, St James’s University
Hospital, Leeds LS9 7TF, United Kingdom
| | - Thomas A. Hughes
- School
of Medicine, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Arwen I. I. Tyler
- School
of Food Science and Nutrition, University
of Leeds, Leeds LS2 9JT, United Kingdom
| | - Paul A. Millner
- School
of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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5
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Nampi PP, Vakurov A, Viswambharan H, Schneider JE, Brydson R, Millner PA, Saha S, Jose G. Barium yttrium fluoride based upconversion nanoparticles as dual mode image contrast agents. Mater Sci Eng C Mater Biol Appl 2021; 124:111937. [PMID: 33947528 DOI: 10.1016/j.msec.2021.111937] [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] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 11/11/2020] [Accepted: 01/31/2021] [Indexed: 11/28/2022]
Abstract
Dual labeled contrast agents could provide better complementary information for bioimaging than available solely from a single modality. In this paper we investigate the suitability of Yb3+ and Er3+-doped BaYF5 upconversion nanoparticles (UCNPs) as both optical and X-ray micro computed tomography (μCT) contrast agents. Stable, aqueous UCNP dispersions were synthesised using a hydrothermal method with the addition of polyethyleneimine (PEI). UCNPs were single crystal and had a truncated cuboidal and/or truncated octahedral morphology, with average particle size of 47 ±9 nm from transmission electron microscopy which was further used to characterize the structure and composition in detail. A zeta potential value of +51 mV was measured for the aqueous nanoparticle dispersions which is beneficial for cell permeability. The outer hydrated PEI layer is also advantageous for the attachment of proteins for targeted delivery in biological systems. The prepared UCNPs were proven to be non-toxic to endothelial cells up to a concentration of 3.5 mg/mL, when assessed using an MTT assay. The particles showed intense green upconversion photoluminescence when excited at a wavelength of 976 nm using a diode laser. Quantitative X-ray μCT contrast imaging confirmed the potential of these UCNPs as X-ray contrast agents and confirming their dual modality for bioimaging.
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Affiliation(s)
- Padmaja Parameswaran Nampi
- School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom; School of Biomedical Sciences, Faculty of Biological, Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom; Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Alexander Vakurov
- School of Biomedical Sciences, Faculty of Biological, Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Hema Viswambharan
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Jürgen E Schneider
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Rik Brydson
- School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Paul A Millner
- School of Biomedical Sciences, Faculty of Biological, Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Sikha Saha
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Gin Jose
- School of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
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6
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Silk ZM, Loughenbury PR, Borse V, Millner PA, Rao AS. A novel technique of temporary reduction to treat double and triple structural curves in patients with adolescent idiopathic scoliosis. Ann R Coll Surg Engl 2021; 103:139-140. [PMID: 33559542 PMCID: PMC9773861 DOI: 10.1308/rcsann.2020.7050] [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: 11/22/2022] Open
Affiliation(s)
- ZM Silk
- Leeds General Infirmary, Leeds, UK
| | | | - V Borse
- Leeds General Infirmary, Leeds, UK
| | | | - AS Rao
- Leeds General Infirmary, Leeds, UK
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7
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Álvarez-Rodríguez B, Tiede C, Hoste ACR, Surtees RA, Trinh CH, Slack GS, Chamberlain J, Hewson R, Fresco A, Sastre P, Tomlinson DC, Millner PA, Edwards TA, Barr JN. Characterization and applications of a Crimean-Congo hemorrhagic fever virus nucleoprotein-specific Affimer: Inhibitory effects in viral replication and development of colorimetric diagnostic tests. PLoS Negl Trop Dis 2020; 14:e0008364. [PMID: 32492018 PMCID: PMC7295242 DOI: 10.1371/journal.pntd.0008364] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/15/2020] [Accepted: 05/05/2020] [Indexed: 12/23/2022] Open
Abstract
Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) is one of the most widespread medically important arboviruses, causing human infections that result in mortality rates of up to 60%. We describe the selection of a high-affinity small protein (Affimer-NP) that binds specifically to the nucleoprotein (NP) of CCHFV. We demonstrate the interference of Affimer-NP in the RNA-binding function of CCHFV NP using fluorescence anisotropy, and its inhibitory effects on CCHFV gene expression in mammalian cells using a mini-genome system. Solution of the crystallographic structure of the complex formed by these two molecules at 2.84 Å resolution revealed the structural basis for this interference, with the Affimer-NP binding site positioned at the critical NP oligomerization interface. Finally, we validate the in vitro application of Affimer-NP for the development of enzyme-linked immunosorbent and lateral flow assays, presenting the first published point-of-care format test able to detect recombinant CCHFV NP in spiked human and animal sera.
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Affiliation(s)
| | - Christian Tiede
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Alexis C. R. Hoste
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
- INGENASA, Inmunología y Genética Aplicada S.A., Madrid, Spain
| | - Rebecca A. Surtees
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Chi H. Trinh
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Gillian S. Slack
- National Infection Service, Public Health England, Porton Down, Salisbury, United Kingdom
| | - John Chamberlain
- National Infection Service, Public Health England, Porton Down, Salisbury, United Kingdom
| | - Roger Hewson
- National Infection Service, Public Health England, Porton Down, Salisbury, United Kingdom
| | - Alba Fresco
- INGENASA, Inmunología y Genética Aplicada S.A., Madrid, Spain
| | - Patricia Sastre
- INGENASA, Inmunología y Genética Aplicada S.A., Madrid, Spain
| | - Darren C. Tomlinson
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Paul A. Millner
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Thomas A. Edwards
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - John N. Barr
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
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8
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Nampi PP, Vakurov A, Mackenzie LE, Scrutton NS, Millner PA, Jose G, Saha S. Selective cellular imaging with lanthanide-based upconversion nanoparticles. J Biophotonics 2019; 12:e201800256. [PMID: 30350344 PMCID: PMC7065621 DOI: 10.1002/jbio.201800256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 10/12/2018] [Accepted: 10/20/2018] [Indexed: 06/08/2023]
Abstract
Upconversion nanoparticles (UCNPs) with sodium yttrium fluoride, NaYF4 (host lattice) doped with Yb3+ (sensitizer) and Er3+ (activator) were synthesized via hydrothermal route incorporating polyethyleneimine (PEI) for their long-term stability in water. The cationic PEI-modified UCNPs with diameter 20 ± 4 nm showed a zeta potential value of +36.5 mV and showed an intense, visible red luminescence and low-intensity green emission with 976 nm laser excitation. The particles proven to be nontoxic to endothelial cells, with a 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay, showing 90% to 100% cell viability, across a wide range of UCNP concentrations (0.3 ng/mL-0.3 mg/mL) were used in multiphoton imaging. Multiphoton cellular imaging and emission spectroscopy data reported here prove that the UCNPs dispersed in cell culture media are predominantly concentrated in the cytoplasm than the cell nucleus. The energy transfer from PEI-coated UCNPs to surrounding media for red luminescence in the biological system is also highlighted with spectroscopic measurements. Results of this study propose that UCNPs can, therefore, be used for cytoplasm selective imaging together with multiphoton dyes (eg, 4',6-diamidino-2-phenylindole (DAPI)) that are selective to cell nucleus.
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Affiliation(s)
- Padmaja P. Nampi
- School of Chemical and Process Engineering, Faculty of EngineeringUniversity of LeedsLeeds LS2 9JTUK
| | - Alexander Vakurov
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeeds LS2 9JTUK
- School of ChemistryUniversity of LeedsLeeds LS2 9JTUK
| | - Lewis E. Mackenzie
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeeds LS2 9JTUK
- Department of ChemistryDurham UniversityDurhamUK
| | - Nigel S. Scrutton
- Manchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterManchesterUK
| | - Paul A. Millner
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeeds LS2 9JTUK
| | - Gin Jose
- School of Chemical and Process Engineering, Faculty of EngineeringUniversity of LeedsLeeds LS2 9JTUK
| | - Sikha Saha
- Leeds Institute for Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and HealthUniversity of LeedsLeeds LS2 9JTUK
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9
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Mackenzie LE, Goode JA, Vakurov A, Nampi PP, Saha S, Jose G, Millner PA. The theoretical molecular weight of NaYF 4 :RE upconversion nanoparticles. Sci Rep 2018; 8:1106. [PMID: 29348590 PMCID: PMC5773537 DOI: 10.1038/s41598-018-19415-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 12/21/2017] [Indexed: 12/28/2022] Open
Abstract
Upconversion nanoparticles (UCNPs) are utilized extensively for biomedical imaging, sensing, and therapeutic applications, yet the molecular weight of UCNPs has not previously been reported. Herein, we present a theory based upon the crystal structure of UCNPs to estimate the molecular weight of UCNPs: enabling insight into UCNP molecular weight for the first time. We estimate the theoretical molecular weight of various UCNPs reported in the literature, predicting that spherical NaYF4 UCNPs ~ 10 nm in diameter will be ~1 MDa (i.e. 106 g/mol), whereas UCNPs ~ 45 nm in diameter will be ~100 MDa (i.e. 108 g/mol). We also predict that hexagonal crystal phase UCNPs will be of greater molecular weight than cubic crystal phase UCNPs. Additionally we find that a Gaussian UCNP diameter distribution will correspond to a lognormal UCNP molecular weight distribution. Our approach could potentially be generalised to predict the molecular weight of other arbitrary crystalline nanoparticles: as such, we provide stand-alone graphic user interfaces to calculate the molecular weight both UCNPs and arbitrary crystalline nanoparticles. We expect knowledge of UCNP molecular weight to be of wide utility in biomedical applications where reporting UCNP quantity in absolute numbers or molarity will be beneficial for inter-study comparison and repeatability.
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Affiliation(s)
- Lewis E Mackenzie
- Department of Chemistry, Faculty of Sciences, Durham University, Durham, DH1 4ED, United Kingdom.
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom.
| | - Jack A Goode
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Alexandre Vakurov
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Padmaja P Nampi
- School of Chemical and Process Engineering, Faculty of Engineering, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Sikha Saha
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Gin Jose
- School of Chemical and Process Engineering, Faculty of Engineering, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Paul A Millner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
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10
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Abstract
Biosensors are ideally portable, low-cost tools for the rapid detection of pathogens, proteins, and other analytes. The global biosensor market is currently worth over 10 billion dollars annually and is a burgeoning field of interdisciplinary research that is hailed as a potential revolution in consumer, healthcare, and industrial testing. A key barrier to the widespread adoption of biosensors, however, is their cost. Although many systems have been validated in the laboratory setting and biosensors for a range of analytes are proven at the concept level, many have yet to make a strong commercial case for their acceptance. Though it is true with the development of cheaper electrodes, circuits, and components that there is a downward pressure on costs, there is also an emerging trend toward the development of multianalyte biosensors that is pushing in the other direction. One way to reduce the cost that is suitable for certain systems is to enable their reuse, thus reducing the cost per test. Regenerating biosensors is a technique that can often be used in conjunction with existing systems in order to reduce costs and accelerate the commercialization process. This article discusses the merits and drawbacks of regeneration schemes that have been proven in various biosensor systems and indicates parameters for successful regeneration based on a systematic review of the literature. It also outlines some of the difficulties encountered when considering the role of regeneration at the point of use. A brief meta-analysis has been included in this review to develop a working definition for biosensor regeneration, and using this analysis only ∼60% of the reported studies analyzed were deemed a success. This highlights the variation within the field and the need to normalize regeneration as a standard process across the field by establishing a consensus term.
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Affiliation(s)
- J A Goode
- †School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- ‡AbCam Plc, Cambridge, United Kingdom
| | - J V H Rushworth
- †School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- §School of Allied Health Sciences, Faculty of Health and Life Sciences, De Montfort University, Leicester, United Kingdom
| | - P A Millner
- †School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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11
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Tiernan JP, Ingram N, Marston G, Perry SL, Rushworth JV, Coletta PL, Millner PA, Jayne DG, Hughes TA. CEA-targeted nanoparticles allow specific in vivo fluorescent imaging of colorectal cancer models. Nanomedicine (Lond) 2015; 10:1223-31. [DOI: 10.2217/nnm.14.202] [Citation(s) in RCA: 28] [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] Open
Abstract
Fluorescent imaging of colorectal tumor cells would improve tumor localization and allow intra-operative staging, facilitating stratification of surgical resections thereby improving patient outcomes. We aimed to develop and test fluorescent nanoparticles capable of allowing this in vivo. Dye-doped silica nanoparticles were synthesized. Anti-CEA (carcinoembryonic antigen) or control IgGs were conjugated to nanoparticles using various chemical strategies. Binding of CEA-targeted or control nanoparticles to colorectal cancer cells was quantified in vitro, and in vivo after systemic-delivery to murine xenografts. CEA-targeted, polyamidoamine dendrimer-conjugated, nanoparticles, but not control nanoparticles, allowed strong tumor-specific imaging. We are the first to demonstrate live, specific, in vivo imaging of colorectal cancer cells using antibody-targeted fluorescent nanoparticles. These nanoparticles have potential to allow intra-operative fluorescent visualization of tumor cells.
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Affiliation(s)
- James P Tiernan
- School of Medicine, University of Leeds, Leeds, LS9 7TF, UK
- John Goligher Colorectal Unit, St James's University Hospital, Leeds, LS9 7TF, UK
| | - Nicola Ingram
- School of Medicine, University of Leeds, Leeds, LS9 7TF, UK
| | - Gemma Marston
- School of Medicine, University of Leeds, Leeds, LS9 7TF, UK
| | - Sarah L Perry
- School of Medicine, University of Leeds, Leeds, LS9 7TF, UK
| | - Jo V Rushworth
- School of Allied Health Sciences, De Montfort University, Leicester, LE1 9BH, UK
| | | | - Paul A Millner
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - David G Jayne
- School of Medicine, University of Leeds, Leeds, LS9 7TF, UK
- John Goligher Colorectal Unit, St James's University Hospital, Leeds, LS9 7TF, UK
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12
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Hyde EDE, Moreno-Atanasio R, Millner PA, Neville F. Surface Charge Control through the Reversible Adsorption of a Biomimetic Polymer on Silica Particles. J Phys Chem B 2015; 119:1726-35. [DOI: 10.1021/jp5100439] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | | | - Paul A. Millner
- Faculty
of Biological Sciences, The University of Leeds, Leeds, LS2 9JT, U.K
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13
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Abstract
Bacterial pathogens are important targets for detection and identification in medicine, food safety, public health, and security. Bacterial infection is a common cause of morbidity and mortality worldwide. In spite of the availability of antibiotics, these infections are often misdiagnosed or there is an unacceptable delay in diagnosis. Current methods of bacterial detection rely upon laboratory-based techniques such as cell culture, microscopic analysis, and biochemical assays. These procedures are time-consuming and costly and require specialist equipment and trained users. Portable stand-alone biosensors can facilitate rapid detection and diagnosis at the point of care. Biosensors will be particularly useful where a clear diagnosis informs treatment, in critical illness (e.g., meningitis) or to prevent further disease spread (e.g., in case of food-borne pathogens or sexually transmitted diseases). Detection of bacteria is also becoming increasingly important in antibioterrorism measures (e.g., anthrax detection). In this review, we discuss recent progress in the use of biosensors for the detection of whole bacterial cells for sensitive and earlier identification of bacteria without the need for sample processing. There is a particular focus on electrochemical biosensors, especially impedance-based systems, as these present key advantages in terms of ease of miniaturization, lack of reagents, sensitivity, and low cost.
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Affiliation(s)
- Asif Ahmed
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Jo V Rushworth
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Natalie A Hirst
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Paul A Millner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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14
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Hirst NA, Tiernan JP, Millner PA, Jayne DG. Systematic review of methods to predict and detect anastomotic leakage in colorectal surgery. Colorectal Dis 2014; 16:95-109. [PMID: 23992097 DOI: 10.1111/codi.12411] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [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] [Received: 02/14/2013] [Accepted: 05/01/2013] [Indexed: 12/11/2022]
Abstract
AIM Anastomotic leakage is a serious complication of gastrointestinal surgery resulting in increased morbidity and mortality, poor function and predisposing to cancer recurrence. Earlier diagnosis and intervention can minimize systemic complications but is hindered by current diagnostic methods that are non-specific and often uninformative. The purpose of this paper is to review current developments in the field and to identify strategies for early detection and treatment of anastomotic leakage. METHOD A systematic literature search was performed using the MEDLINE, Embase, PubMed and Cochrane Library databases. Search terms included 'anastomosis' and 'leak' and 'diagnosis' or 'detection' and 'gastrointestinal' or 'colorectal'. Papers concentrating on the diagnosis of gastrointestinal anastomotic leak were identified and further searches were performed by cross-referencing. RESULTS Computerized tomography CT scanning and water-soluble contrast studies are the current preferred techniques for diagnosing anastomotic leakage but suffer from variable sensitivity and specificity, have logistical constraints and may delay timely intervention. Intra-operative endoscopy and imaging may offer certain advantages, but the ability to predict anastomotic leakage is unproven. Newer techniques involve measurement of biomarkers for anastomotic leakage and have the potential advantage of providing cheap real-time monitoring for postoperative complications. CONCLUSION Current diagnostic tests often fail to diagnose anastomotic leak at an early stage that enables timely intervention and minimizes serious morbidity and mortality. Emerging technologies, based on detection of local biomarkers, have achieved proof of concept status but require further evaluation to determine whether they translate into improved patient outcomes. Further research is needed to address this important, yet relatively unrecognized, area of unmet clinical need.
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Affiliation(s)
- N A Hirst
- Section of Translational Anaesthesia and Surgical Sciences, Leeds Institute of Molecular Medicine, St James's University Hospital, Leeds, UK
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15
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Rushworth JV, Ahmed A, Griffiths HH, Pollock NM, Hooper NM, Millner PA. A label-free electrical impedimetric biosensor for the specific detection of Alzheimer's amyloid-beta oligomers. Biosens Bioelectron 2013; 56:83-90. [PMID: 24480125 DOI: 10.1016/j.bios.2013.12.036] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [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: 10/02/2013] [Revised: 12/02/2013] [Accepted: 12/16/2013] [Indexed: 12/30/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, with over 37 million sufferers worldwide and a global cost of over $600 billion. There is currently no cure for AD and no reliable method of diagnosis other than post-mortem brain examination. The development of a point-of-care test for AD is an urgent requirement in order to provide earlier diagnosis and, thus, useful therapeutic intervention. Here, we present a novel, label-free impedimetric biosensor for the specific detection of amyloid-beta oligomers (AβO), which are the primary neurotoxic species in AD. AβO have been proposed as the best biomarker for AD and levels of AβO in the blood have been found to correlate with cerebrospinal fluid load. The biorecognition element of our biosensor is a fragment of the cellular prion protein (PrP(C), residues 95-110), a highly expressed synaptic protein which mediates the neuronal binding and toxicity of AβO. During the layer-by-layer sensor construction, biotinylated PrP(C) (95-110) was attached via a biotin/NeutrAvidin bridge to polymer-functionalised gold screen-printed electrodes. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry and scanning electron microscopy were used to validate biosensor assembly and functionality. EIS was employed for biosensor interrogation in the presence of Aβ oligomers or monomers. The biosensor was specific for the detection of synthetic AβO and gave a linear response, without significant detection of monomeric Aβ, down to an equivalent AβO concentration of ~0.5 pM. The biosensor was also able to detect natural, cell-derived AβO present in conditioned medium. The eventual commercialisation of this biosensor system could allow for the early diagnosis and disease monitoring of AD.
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Affiliation(s)
- Jo V Rushworth
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
| | - Asif Ahmed
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Heledd H Griffiths
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Niall M Pollock
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Nigel M Hooper
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Paul A Millner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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16
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Ahmed A, Rushworth JV, Wright JD, Millner PA. Novel impedimetric immunosensor for detection of pathogenic bacteria Streptococcus pyogenes in human saliva. Anal Chem 2013; 85:12118-25. [PMID: 24256123 DOI: 10.1021/ac403253j] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Streptococcus pyogenes , also known as group A streptococcus (GAS), is a Gram positive human pathogen responsible for invasive and noninvasive human infections with a high incidence rate. Traditional detection methods involve cell culture and PCR, which are limited by long processing times or the need for high cost equipment. Impedance-based electrochemical immunosensors provide an alternative by which precise and rapid quantitative detection of the organism can help with rapid clinical decisions. To bring a biosensor for point-of-care applications to market, strict optimization of each level of construction and operation is required. In this paper, commercial screen-printed gold electrodes have been used to construct polytyramine (Ptyr)-based immunosensors. Biotin tagged whole antibodies against S. pyogenes were conjugated to Ptyr amine group via biotin-NeutrAvidin coupling. Sensors were optimized at each level of construction, particularly for Ptyr electrodeposition and antibody concentration, to optimize signal and specificity. Scanning electron microscopy, fluorescence microscopy, and on-sensor analysis (HRP conjugated enhanced chemiluminescence-based semiquantitative method) to detect Ptyr surface amine and bound antibody were performed as supporting techniques. Cumulative and single shot incubations had shown detection range of 100 to 10(5) cells per 10 μL and 100 to 10(4) cells per 10 μL of bacteria in PBS, respectively. Sensors were also able to specifically detect S. pyogenes in 50% (v/v) human saliva, with good selectivity and low cross-reactivity.
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Affiliation(s)
- Asif Ahmed
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds , Leeds LS2 9JT, U.K
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17
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Pike DJ, Kapur N, Millner PA, Stewart DI. Flow cell design for effective biosensing. Sensors (Basel) 2012; 13:58-70. [PMID: 23344373 PMCID: PMC3574664 DOI: 10.3390/s130100058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 12/11/2012] [Accepted: 12/12/2012] [Indexed: 11/16/2022]
Abstract
The efficiency of three different biosensor flow cells is reported. All three flow cells featured a central channel that expands in the vicinity of the sensing element to provide the same diameter active region, but the rate of channel expansion and contraction varied between the designs. For each cell the rate at which the analyte concentration in the sensor chamber responds to a change in the influent analyte concentration was determined numerically using a finite element model and experimentally using a flow-fluorescence technique. Reduced flow cell efficiency with increasing flow rates was observed for all three designs and was related to the increased importance of diffusion relative to advection, with efficiency being limited by the development of regions of recirculating flow (eddies). However, the onset of eddy development occurred at higher flow rates for the design with the most gradual channel expansion, producing a considerably more efficient flow cell across the range of flow rates considered in this study. It is recommended that biosensor flow cells be designed to minimize the tendency towards, and be operated under conditions that prevent the development of flow recirculation.
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Affiliation(s)
- Douglas J. Pike
- Pathogen Control Engineering (PaCE) Institute, School of Civil Engineering, University of Leeds, Leeds, West Yorkshire, LS2 9JT, UK; E-Mail:
| | - Nikil Kapur
- Institute of Engineering Thermofluids, Surfaces & Interfaces (iETSI), School of Mechanical Engineering, University of Leeds, Leeds, West Yorkshire, LS2 9JT, UK; E-Mail:
| | - Paul A. Millner
- Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire, LS2 9JT, UK; E-Mail:
| | - Douglas I. Stewart
- Pathogen Control Engineering (PaCE) Institute, School of Civil Engineering, University of Leeds, Leeds, West Yorkshire, LS2 9JT, UK; E-Mail:
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18
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Abstract
AIM Surgical resection for colorectal cancer involves segmental resection and regional lymphadenectomy. The appropriateness of this 'one-size-fits-all' strategy is questioned as bowel cancer screening programmes result in a shift to earlier stage disease. Currently, the nodal status of a colorectal cancer can only be reliably determined by histopathological examination of the resected specimen. New methods of intra-operative staging are required to allow surgical resection to be tailored to the stage of the disease. METHOD A literature search was performed of PubMed and Embase databases using the terms 'colon' OR 'colorectal' AND 'intra-operative detection' OR 'intra-operative staging' OR 'intra-operative detection' OR 'radioimmunoguided surgery'. Articles published between January 1980 and January 2012 were included. Technologies that have the potential to allow intra-operative staging and treatment stratification were identified and further searches performed. RESULTS Established techniques such as sentinel lymph node mapping and radioimmunoguided surgery have benefited from combination with other technologies to allow real-time intra-operative staging. Intra-operative fluorescence, using naturally fluorescent biomarkers or fluorescent tumour probes, probably offers the most practical means of intra-operative lymph node staging and may be facilitated using nanotechnology. Optical coherence tomography and real-time elastography have the potential to provide an in vivo'virtual biopsy'. CONCLUSION Technological advances may allow accurate intra-operative lymph node staging to facilitate tailored surgical resection. This may become the next paradigm shift in colorectal cancer surgery.
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Affiliation(s)
- J P Tiernan
- Section of Translational Anaesthetic and Surgical Sciences, Leeds Institute of Molecular Medicine, St James's University Hospital, Leeds, UK.
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19
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Neville F, Broderick MJF, Gibson T, Millner PA. Fabrication and activity of silicate nanoparticles and nanosilicate-entrapped enzymes using polyethyleneimine as a biomimetic polymer. Langmuir 2011; 27:279-285. [PMID: 21121623 DOI: 10.1021/la1033492] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In nature, some peptides induce precipitation of silicic acid into silica nanoparticles such as is found in marine algae called diatoms. However, polybasic polymers can act as peptide mimics; one such polymer, polyethyleneimine (PEI), has the advantage that it is stable at room temperature and is inexpensive, in comparison with synthetic peptides. We describe the fabrication and characterization of biosilicate nanoparticles formed by mimicking the peptides using PEI. Brownian motion nanoparticle tracking analysis and field emission gun scanning electron microscopy have been used for the first time to characterize nanoparticles made with tetramethyl orthosilicate (TMOS) and PEI to investigate the fundamental factors that affect particle properties. These factors include the effect of phosphate concentration, PEI molecular weight, TMOS concentration, and species of alkoxy-silane used. The properties of the particles are compared with other particles made with polymers that induce silication. Our results show that using PEI gives differences in particle size compared with previous work using other polymers that induce silication. The entrapment of enzymes during the silication process, rationale for using nonphosphate and phosphate buffers during enzyme entrapment, and the analysis of enzyme activity are also presented. Because enzymes can be entrapped during fabrication, it means that there are many future possibilities for the use of silicate nanoparticles containing enzymes, such as biosensors and biocatalytic reactors.
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Affiliation(s)
- Frances Neville
- Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
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20
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Conroy DJ, Millner PA, Stewart DI, Pollmann K. Biosensing for the environment and defence: aqueous uranyl detection using bacterial surface layer proteins. Sensors (Basel) 2010; 10:4739-55. [PMID: 22399904 PMCID: PMC3292144 DOI: 10.3390/s100504739] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/22/2010] [Accepted: 04/27/2010] [Indexed: 11/24/2022]
Abstract
The fabrication of novel uranyl (UO(2)(2+)) binding protein based sensors is reported. The new biosensor responds to picomolar levels of aqueous uranyl ions within minutes using Lysinibacillus sphaericus JG-A12 S-layer protein tethered to gold electrodes. In comparison to traditional self assembled monolayer based biosensors the porous bioconjugated layer gave greater stability, longer electrode life span and a denser protein layer. Biosensors responded specifically to UO(2)(2+) ions and showed minor interference from Ni(2+), Cs(+), Cd(2+) and Co(2+). Chemical modification of JG-A12 protein phosphate and carboxyl groups prevented UO(2)(2+) binding, showing that both moieties are involved in the recognition to UO(2)(2+).
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Affiliation(s)
- David J.R. Conroy
- Biosensors and Biocatalysis Group, Institute of Membranes and Systems Biology, University of Leeds, Leeds, LS2 9JT, UK; E-Mail:
| | - Paul A. Millner
- Biosensors and Biocatalysis Group, Institute of Membranes and Systems Biology, University of Leeds, Leeds, LS2 9JT, UK; E-Mail:
| | - Douglas I. Stewart
- School of Civil Engineering, University of Leeds, Leeds LS2 9JT, UK; E-Mail:
| | - Katrin Pollmann
- Institute of Radiochemistry, Forschungszentrum Dresden, Rossendorf, Germany; E-Mail:
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21
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Neville F, Pchelintsev NA, Broderick MJF, Gibson T, Millner PA. Novel one-pot synthesis and characterization of bioactive thiol-silicate nanoparticles for biocatalytic and biosensor applications. Nanotechnology 2009; 20:055612. [PMID: 19417359 DOI: 10.1088/0957-4484/20/5/055612] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A novel one-pot neutral synthesis using bioinspired polymers to fabricate thiol-nanoparticles is presented. The thiol-particles may be directly tethered to metal surfaces such as gold, allowing the production of self-assembled nanostructured biocatalytic or biosensor surfaces. This one-pot method has also been used to entrap enzymes within the thiol-nanoparticles; it is apparent that once enzyme entrapment is carried out a bimodal distribution of particles is formed, with particles of one mode being very similar in size to thiol-nanoparticles without enzyme entrapped, and particles of the other mode being much larger in size. To this end, efforts have been made to separate the two modes of particles for the sample containing enzyme and it has been observed that the larger mode thiol-nanoparticles do indeed contain significant amounts of enzyme in comparison to the smaller mode ones. As the enzyme-containing thiol-nanoparticles can now be isolated, this means that there are many future possibilities for the use of thiol-particles containing enzyme, as they may be used in a wide range of processes and devices which require catalytic functionalized surfaces, such as biosensors and biocatalytic reactors.
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Affiliation(s)
- Frances Neville
- Institute of Membrane and Systems Biology, University of Leeds, Leeds, UK.
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22
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Barton AC, Collyer SD, Davis F, Garifallou GZ, Tsekenis G, Tully E, O’Kennedy R, Gibson T, Millner PA, Higson SP. Labeless AC impedimetric antibody-based sensors with pgml−1 sensitivities for point-of-care biomedical applications. Biosens Bioelectron 2009; 24:1090-5. [DOI: 10.1016/j.bios.2008.06.001] [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] [Received: 03/04/2008] [Revised: 04/16/2008] [Accepted: 06/04/2008] [Indexed: 02/03/2023]
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23
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Tsekenis G, Garifallou GZ, Davis F, Millner PA, Pinacho DG, Sanchez-Baeza F, Marco MP, Gibson TD, Higson SPJ. Detection of Fluoroquinolone Antibiotics in Milk via a Labeless Immunoassay Based upon an Alternating Current Impedance Protocol. Anal Chem 2008; 80:9233-9. [DOI: 10.1021/ac8014752] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Georgios Tsekenis
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Goulielmos-Zois Garifallou
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Frank Davis
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Paul A. Millner
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Daniel G. Pinacho
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Francisco Sanchez-Baeza
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - M.-Pilar Marco
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Tim D. Gibson
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
| | - Séamus P. J. Higson
- Cranfield Health, Cranfield University, Silsoe, Bedfordshire, MK45 4DT, U.K., School of Biochemistry and Molecular Biology, University of Leeds, Leeds, LS2 9JT, U.K., Applied Molecular Receptors Group (AMRg), CSIC, CIBER of Bioengineering, Biomaterials and Nanomedicine, Jorge Girona 18-26, 08034-Barcelona, Spain, and T and D Technology Ltd., Wakefield, West Yorkshire, WF3 4AA, U.K
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24
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Meller Harel HY, Fontaine V, Chen H, Jones IM, Millner PA. Display of a maize cDNA library on baculovirus infected insect cells. BMC Biotechnol 2008; 8:64. [PMID: 18700036 PMCID: PMC2527309 DOI: 10.1186/1472-6750-8-64] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 08/12/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Maize is a good model system for cereal crop genetics and development because of its rich genetic heritage and well-characterized morphology. The sequencing of its genome is well advanced, and new technologies for efficient proteomic analysis are needed. Baculovirus expression systems have been used for the last twenty years to express in insect cells a wide variety of eukaryotic proteins that require complex folding or extensive posttranslational modification. More recently, baculovirus display technologies based on the expression of foreign sequences on the surface of Autographa californica (AcMNPV) have been developed. We investigated the potential of a display methodology for a cDNA library of maize young seedlings. RESULTS We constructed a full-length cDNA library of young maize etiolated seedlings in the transfer vector pAcTMVSVG. The library contained a total of 2.5 x 10(5) independent clones. Expression of two known maize proteins, calreticulin and auxin binding protein (ABP1), was shown by western blot analysis of protein extracts from insect cells infected with the cDNA library. Display of the two proteins in infected insect cells was shown by selective biopanning using magnetic cell sorting and demonstrated proof of concept that the baculovirus maize cDNA display library could be used to identify and isolate proteins. CONCLUSION The maize cDNA library constructed in this study relies on the novel technology of baculovirus display and is unique in currently published cDNA libraries. Produced to demonstrate proof of principle, it opens the way for the development of a eukaryotic in vivo display tool which would be ideally suited for rapid screening of the maize proteome for binding partners, such as proteins involved in hormone regulation or defence.
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Affiliation(s)
| | - Veronique Fontaine
- UMR INRA/USTL 1281, Stress Abiotiques et Différenciation des Végétaux cultivés 2, Chaussée Brunehaut, Estrées-Mons BP 50136, 80203 Péronne cedex, France
| | - Hongying Chen
- School of Biological Sciences, University of Reading, Whiteknights, Reading, Berks, RG6 6AJ, UK
| | - Ian M Jones
- School of Biological Sciences, University of Reading, Whiteknights, Reading, Berks, RG6 6AJ, UK
| | - Paul A Millner
- Faculty of biological sciences, University of Leeds, Leeds, LS2 9JT, UK
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25
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Tsekenis G, Garifallou GZ, Davis F, Millner PA, Gibson TD, Higson SPJ. Label-less Immunosensor Assay for Myelin Basic Protein Based upon an ac Impedance Protocol. Anal Chem 2008; 80:2058-62. [DOI: 10.1021/ac702070e] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Georgios Tsekenis
- Cranfield Health, Cranfield University, Silsoe, Beds, MK45 4DT, U.K., Biosensors and Biocatalysis Group, Research Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, U.K., and ELISHA Systems Limited, Sigma House, Burlow Road, Buxton, SK17 9JB, U.K
| | - Goulielmos-Zois Garifallou
- Cranfield Health, Cranfield University, Silsoe, Beds, MK45 4DT, U.K., Biosensors and Biocatalysis Group, Research Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, U.K., and ELISHA Systems Limited, Sigma House, Burlow Road, Buxton, SK17 9JB, U.K
| | - Frank Davis
- Cranfield Health, Cranfield University, Silsoe, Beds, MK45 4DT, U.K., Biosensors and Biocatalysis Group, Research Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, U.K., and ELISHA Systems Limited, Sigma House, Burlow Road, Buxton, SK17 9JB, U.K
| | - Paul A. Millner
- Cranfield Health, Cranfield University, Silsoe, Beds, MK45 4DT, U.K., Biosensors and Biocatalysis Group, Research Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, U.K., and ELISHA Systems Limited, Sigma House, Burlow Road, Buxton, SK17 9JB, U.K
| | - Tim D. Gibson
- Cranfield Health, Cranfield University, Silsoe, Beds, MK45 4DT, U.K., Biosensors and Biocatalysis Group, Research Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, U.K., and ELISHA Systems Limited, Sigma House, Burlow Road, Buxton, SK17 9JB, U.K
| | - Séamus P. J. Higson
- Cranfield Health, Cranfield University, Silsoe, Beds, MK45 4DT, U.K., Biosensors and Biocatalysis Group, Research Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, U.K., and ELISHA Systems Limited, Sigma House, Burlow Road, Buxton, SK17 9JB, U.K
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26
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Billah M, Hays HCW, Millner PA. Development of a myoglobin impedimetric immunosensor based on mixed self-assembled monolayer onto gold. Mikrochim Acta 2007. [DOI: 10.1007/s00604-007-0793-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Hannah MA, Krämer KM, Geffroy V, Kopka J, Blair MW, Erban A, Vallejos CE, Heyer AG, Sanders FET, Millner PA, Pilbeam DJ. Hybrid weakness controlled by the dosage-dependent lethal (DL) gene system in common bean (Phaseolus vulgaris) is caused by a shoot-derived inhibitory signal leading to salicylic acid-associated root death. New Phytol 2007; 176:537-549. [PMID: 17850251 DOI: 10.1111/j.1469-8137.2007.02215.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Certain crosses of common bean (Phaseolus vulgaris) result in temperature-dependent hybrid weakness associated with a severe root phenotype. This is controlled by the interaction of the root- and shoot-expressed semidominant alleles dosage-dependent lethal 1 (DL(1)) and DL(2), which communicate via long-distance signaling. Previously, apparent reciprocal effects on root growth and the restoration of normal root growth by exogenous sucrose led to the hypothesis that the dosage-dependent lethal (DL) system may control root-shoot carbon partitioning. Here, recombinant inbred lines were used to map the DL loci and physiological and biochemical analysis, including metabolite profiling, was used to gain new insights into the signaling interaction and the root phenotype. It is shown that the DL system does not control root-shoot carbon partitioning and that roots are unlikely to die from carbon starvation. Instead, root death likely occurs by defense-related programmed cell death, as indicated by salicylic acid accumulation. DL(2)-expressing cotyledons supply a potent inhibitory signal that is sufficient to cause such death in DL(1)-expressing roots. These data implicate the DL system in defense-related signaling and provide support for the recent hypothesis of defense-related autoimmunity as a potential isolating mechanism in plant speciation, in particular, setting a precedence for the potential roles of long-distance signaling and temperature dependence.
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Affiliation(s)
- Matthew A Hannah
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenburg 1, 14476 Golm, Germany
| | - K Melanie Krämer
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenburg 1, 14476 Golm, Germany
| | - Valerie Geffroy
- INRA, Institut de Biotechnologie des Plantes, UMR-CNRS 8618, LPPM, bât. 630, Université Paris-Sud, 91405 Orsay, France
| | - Joachim Kopka
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenburg 1, 14476 Golm, Germany
| | - Matthew W Blair
- Centro Internacional de Agricultura Tropical, AA 6713, Cali, Colombia
| | - Alexander Erban
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenburg 1, 14476 Golm, Germany
| | - C Eduardo Vallejos
- Department of Horticultural Sciences, and Plant Molecular and Cellular Biology Program, 1143 Fifield Hall, University of Florida, Gainesville, FL 32611-0690, USA
| | - Arnd G Heyer
- Biologisches Institut, Abt. Botanik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | | | | | - David J Pilbeam
- Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK
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29
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Hays HCW, Millner PA, Jones JK, Rayner-Brandes MH. A novel and convenient self-drying system for bacterial preservation. J Microbiol Methods 2005; 63:29-35. [PMID: 16157210 DOI: 10.1016/j.mimet.2005.02.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2004] [Revised: 01/09/2005] [Accepted: 02/17/2005] [Indexed: 10/25/2022]
Abstract
An effective microbial preservation technology for the long-term storage of viable prokaryotic cells is described. The method combines an almost instantaneous drying step with minimal stress to the cells during drying to maximize survival on rehydration. This is achieved by contact of a microlitre aliquot of a bacterial suspension with a novel, pre-dried activated charcoal cloth based matrix contained within a re-sealable system that can then be stored. The simple methodology completely circumvents the requirement for further drying or preparation. Using this method, a standard laboratory Escherichia coli strain was successfully revived following 390 days storage at 4, 20 and 30 degrees C. Data obtained yielded approximately 20%, 6% and 0.1% viable organisms at the aforementioned temperatures, respectively, following initial inoculations of 1.1 x 10(8)/microl cells. While these figures represent a significant viability loss, there is sufficient recovery of microorganisms required for maintaining culture collections.
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Affiliation(s)
- Henry C W Hays
- University of Leeds, Biochemistry and Microbiology, Woodhouse Lane, Leeds LS2 9JT, UK.
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30
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Vakurov A, Simpson CE, Daly CL, Gibson TD, Millner PA. Acetylecholinesterase-based biosensor electrodes for organophosphate pesticide detection. II. Immobilization and stabilization of acetylecholinesterase. Biosens Bioelectron 2005; 20:2324-9. [PMID: 15797334 DOI: 10.1016/j.bios.2004.07.022] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [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: 04/19/2004] [Revised: 07/16/2004] [Accepted: 07/22/2004] [Indexed: 11/25/2022]
Abstract
The dry and wet stability of Drosophila acetylcholinesterase non-covalently immobilized onto polyethyleneimine modified screen-printed carbon electrodes was improved when compared to non-immobilized acetylcholinesterase, and acetylcholinesterase covalently immobilized onto dialdehyde and polyethyleneimine modified electrodes. Stabilizer mixtures were characterized for additional stabilization of acetylcholinesterase during storage in the dry state, with dextran-sulphate/sucrose and polygalacturonic acid/sucrose mixtures proving highly effective for long-term storage of biosensor electrodes.
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Affiliation(s)
- A Vakurov
- School of Biochemistry and Microbiology, University of Leeds, Leeds, LS2 9JT, UK
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31
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Berry E, Cuppone M, Porada S, Millner PA, Rao A, Chiverton N, Seedhom BB. Personalised image-based templates for intra-operative guidance. Proc Inst Mech Eng H 2005; 219:111-8. [PMID: 15819482 DOI: 10.1243/095441105x9273] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [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: 11/18/2022]
Abstract
The high rate of unplanned perforation, poor fixation, and nerve injury with freehand pedicle screw insertion has led to the use of image-guided navigation systems. Although these improve accuracy, they have several drawbacks that could be overcome by using image-based drilling guide templates. The accuracy of such templates was tested in a cadaveric study of screw placement in the lumbar, thoracic, and cervical regions of the spine. The dimensional stability with autoclaving of duraform polyamide, to be used for manufacturing the guides, was first determined using test specimens. Computed tomography (CT) images were acquired of 4 cadaveric spines, and placement of 4 cervical, 32 thoracic, and 14 lumbar screws was planned. Eighteen personalized drilling guide templates, in four different designs, were built. Orthopaedic surgeons experienced in the freehand techniques used the templates. CT images were acquired to assess placement position with respect to the pedicle. Duraform polyamide was found to be unaffected by sterilization. Two of the template designs facilitated the placement of 20/20 screws without error. Templates can lead to successful screw placement, even in small pedicles, providing their design is optimized for the application area, e.g. with enhanced rotational stabilization.
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Affiliation(s)
- E Berry
- Academic Unit of Medical Physics, University of Leeds, Leeds, UK.
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32
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Elnashar MM, Millner PA, Johnson AF, Gibson TD. Parallel plate equipment for preparation of uniform gel sheets. Biotechnol Lett 2005; 27:737-9. [PMID: 16049744 DOI: 10.1007/s10529-005-5363-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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: 03/03/2005] [Revised: 04/06/2005] [Accepted: 04/07/2005] [Indexed: 11/28/2022]
Abstract
A method for the preparation of uniform gel-disks for enzyme and cell immobilisation, as well as for characterisation of gel mechanical stability, is described. The apparatus comprises a stainless steel base unit and glass parallel plates, designed to permit easy and fast production of multiple homogeneous gel sheets of variable thickness.
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Affiliation(s)
- M M Elnashar
- Schools of Biochemistry & Microbiology, University of Leeds, LS2 9JT, Leeds, UK
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33
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Vakurov A, Simpson CE, Daly CL, Gibson TD, Millner PA. Acetylcholinesterase-based biosensor electrodes for organophosphate pesticide detection. Biosens Bioelectron 2004; 20:1118-25. [PMID: 15556357 DOI: 10.1016/j.bios.2004.03.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Revised: 02/20/2004] [Accepted: 03/16/2004] [Indexed: 10/26/2022]
Abstract
Screen-printed carbon electrodes modified with the dialdehydes, glutaraldehyde and terephthaldicarboxaldehyde, and then polyethyleneimine have been utilized for production of pesticide biosensors based on acetylcholinesterase. To improve the extent of dialdehyde modification, the electrodes were NH2-derivatized, initially by electrochemical reduction of 4-nitrobenzenediazonium to a nitroaryl radical permitting attachment to the carbon surface. Subsequent reduction of the 4-nitrobenzene yields a 4-aminobenzene modified carbon surface. Drosophila melanogaster acetylcholinesterase was immobilized either covalently onto dialdehyde modified electrodes or non-covalently onto polyethyleneimine modified electrodes. Internal diffusion limitations due to the dialdehyde and polyethyleneimine modifications increased the apparent Km of the immobilized enzyme. The thiocholine sensitivity was about 90% for dialdehyde modified electrodes and about 10% for polyethyleneimine modified electrodes as compared with non-modified carbon electrodes. The detection limit of the biosensors produced by non-covalent immobilization of acetylcholinesterase onto polyethyleneimine modified carbon electrodes was found to be about 10(-10) M for the organophosphate pesticide dichlorvos.
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Affiliation(s)
- A Vakurov
- School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK
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Abstract
OBJECTIVE To investigate the therapeutic impact of percutaneous spinal biopsy in patients with suspected spinal infection. DESIGN AND PATIENTS A review of the case notes and imaging features of 36 patients who underwent percutaneous spinal biopsy was performed. From this group 20 patients with a prebiopsy diagnosis of spinal osteomyelitis were identified. Management before biopsy was noted including the use of antimicrobial therapy. The results of the histology and microbiology were noted along with the subsequent diagnosis and management. RESULTS Eight of the 20 patients (40%) had received antibiotics before the biopsy. An organism was isolated in 8/20 cases (40%). Of the eight patients on antibiotics, two grew an organism (25%), including one case of candida in a patient receiving flucloxacillin. Out of 12 patients not on antibiotics there were six cases where an organism was isolated (50%). The result of the biopsy led to a change in management in seven of the 20 patients (35%). CONCLUSIONS Many clinicians are treating spinal osteomyelitis empirically with antibiotics before biopsy, but this reduces the chance of isolating an organism and determining antibiotic sensitivity. Despite this biopsy led to a change in management in 35% of cases.
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Affiliation(s)
- J J Rankine
- Department of Clinical Radiology, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK.
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35
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Abstract
STUDY DESIGN This is a retrospective study of all the patients registered with the Yorkshire Regional Cystic Fibrosis unit from 1982 to 1997. Of the 316 patients, there were 184 adults (age 17 years and above) and 132 children (age 0-6 years). OBJECTIVES This study was aimed at determining the prevalence of scoliosis in people with cystic fibrosis and describes the characteristics and progression of scoliosis in these patients and highlights predictive factors, which account for high prevalence of scoliosis in this condition. SUMMARY OF THE BACKGROUND DATA Two previous North American studies (1978 and 1982) have indicated a high prevalence of scoliosis in patients with cystic fibrosis. METHODS The patients were divided into 3 groups based on their chronologic age as on January 1998. Chest, abdomen, and whole spine radiographs were studied for the presence of any spinal deformity, and measurements were made using the Oxford Cobbmeter (Oxford Metrics). The extent, apex, and the side of the curves were described. The disease-specific scores, ie, Chrispin-Norman score (score for radiologic severity of lung disease) and Shwachman score (score for general condition), were noted from the patient follow-up database maintained by the Regional Cystic Fibrosis Unit. Multiple linear regression analysis was used to study the correlation between Cobb angle and the previously mentioned scores. RESULTS In the 4- to 16-year age group, the prevalence of scoliosis was 15.6%, which is 20 times the prevalence in 15,793 school children with a similar age and sex distribution from the same geographic area. The majority of curves were single-thoracic, apical around T6-T8 with no side predilection. In the adult population (above 16 years), the prevalence was 9.8%, which is higher than that of the general population. These curves were thoracic, apical around T7-T8, and approximately two thirds of them were right-sided. Infantile curves are described for the first time in our study; these tend to be nonprogressive, right-sided, upper thoracic curves. CONCLUSION Our study shows a high prevalence of scoliosis in people with cystic fibrosis. These are benign short midthoracic curves, apical between T6-T8 with no side predilection.
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Abstract
Previous studies have indicated that SAG1, the major surface molecule of the protozoan parasite Toxoplasma gondii, is an important attachment ligand for the host cell. However, the research data that supports this claim comes largely from studies investigating tachyzoite binding, and not SAG1 binding per se. In this study we successfully developed an in vitro attachment assay to directly evaluate the mechanism of SAG1-host cell binding. Competition experiments were then performed using SAG1 that had been pre-treated with the neoglycoprotein BSA-glucosamide or with antibody. Soluble BSA-glucosamide blocked SAG1 attachment to MDBK cells in a dose-dependent manner, implying that SAGI binding is mediated, in part, via attachment to host cell surface glucosamine. Interestingly, pre-incubation of SAG1 in polyclonal sera from chronically infected mice failed to block binding. This challenges the assumption that anti-SAG1 antibodies block parasite attachment through the masking of SAG1 host cell binding domains. Taken together, this evidence presents new strategies for understanding SAG1-mediated attachment.
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Affiliation(s)
- S A Robinson
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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37
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Manios T, Stentiford EI, Millner PA. The removal of indicator microorganisms from primary treated wastewater in subsurface reed beds using different substrates. Environ Technol 2002; 23:767-774. [PMID: 12164637 DOI: 10.1080/09593332408618367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Subsurface, horizontal flow, experimental reed beds, were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water Plc and that of the USA, EPA. Four different growing media were used with a combination of top soil, gravel, river sand and mature sewage sludge compost, aiming to determine the best substrate for enteric pathogen removal. Eight units were constructed, two for each material. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary treated domestic wastewater, was continuously fed in to the bed for more than six months. All beds achieved a high reduction of Escherichia coli and faecal coliforms with the best results recorded in the gravel reed beds with an average removal above 3.3 log for E. coli and 3.0 for faecal coliforms. There was no significance difference in the performance of planted and unplanted reed beds.
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Affiliation(s)
- T Manios
- Department of Environmental Engineering, Technical University of Crete, Chania, Greece
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38
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Smith FM, Latchford G, Hall RM, Millner PA, Dickson RA. Indications of disordered eating behaviour in adolescent patients with idiopathic scoliosis. J Bone Joint Surg Br 2002; 84:392-4. [PMID: 12002499 DOI: 10.1302/0301-620x.84b3.12619] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We have investigated whether patients with adolescent-onset idiopathic scoliosis (AIS) are more likely to have a low body-weight. Measurements of weight, height and body mass index (BMI) were made in 44 young women with AIS and compared with age- and gender-adjusted normative data. The body mass criteria of the International Classification of Diseases for eating disorders was used to determine how many patients were within the range considered to be 'eating disordered'. Compared with the normative data, the AIS group did not differ significantly in terms of height, (p = 0.646), but they were significantly lighter (p < 0.001) and had significantly lower BMI scores (p < 0.001); 25% of the series had BMI scores which were within the range considered to be anorexic. The relationship between a diagnosis of AIS and low body-weight may indicate disordered eating and is thus a cause for concern, particularly in the light of the well-established relationship between eating psychopathology and osteoporosis. Aspects of organic health may need to be considered in addition to the cosmetic deformity.
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Affiliation(s)
- F M Smith
- Department of Orthopaedics Surgery, St James's University Hospital, Leeds, England, UK
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39
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Manios T, Stentiford EI, Millner PA. The removal of NH3-N from primary treated wastewater in subsurface reed beds using different substrates. J Environ Sci Health A Tox Hazard Subst Environ Eng 2002; 37:297-308. [PMID: 11929069 DOI: 10.1081/ese-120002829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Subsurface flow experimental reed beds, were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water plc (3) and that of the USA, EPA (17). Four different growing media were used with a combination of top soil, gravel, river sand and mature sewage sludge compost, aiming to determine the best substrate for ammonia removal. Eight units were constructed, two for each material. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary treated domestic wastewater, was continuously fed in to the bed for more than six months. The best results were achieved by the gravel reed beds with an almost constant removal rate of NH3-N above 80%. There was no significance difference on the performance of planted and unplanted reed beds.
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Affiliation(s)
- Thrassyvoulos Manios
- Department of Environmental Engineering, Technical University of Crete, Chania, Greece.
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40
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Mello LV, Millner PA, Findlay JBC. Biochemical characteristics of guanine nucleotide binding protein alpha-subunit recombinant protein and three mutants: investigation of a domain motion involved in GDP-GTP exchange. J Protein Chem 2002; 21:29-34. [PMID: 11905447 DOI: 10.1023/a:1014127015042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Our previous studies using molecular dynamics have shown a hinge bending motion between the helical and the GTPase domains of GalphaT (Mello et al., 1998). The hypothesis that this motion is allowed by residues Gly56 and Gly179 and that this motion may affect the ligand exchange was tested in this work. Mutations of Gly 56 were carried out and the mutant proteins were expressed in Sf9 cells using the Baculovirus expression system. The recombinant proteins were purified using Ni-NTA affinity chromatography. The results for the (GDP/GTP) exchange assays showed that G56S and double mutants (D55G/G56S) proteins differ significantly from the wild type and D55G mutant forms. The Kd values for GTPgammaS binding of those mutants have decreased by approximately 10-fold. No difference in the GTPase activity was detected for the mutants. Thus, the biochemical results obtained support the conclusions of the computational studies.
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Affiliation(s)
- L V Mello
- School of Biochemistry and Molecular Biology, University of Leeds, UK.
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41
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42
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Abstract
Heterotrimeric G-proteins, which couple cell surface receptors with internal effectors, are evident in all eukaryotes. Their operation involves receptor activation, GTP/GDP exchange and modulation of effector activity; deactivation occurs by an intrinsic GTPase activity. Structurally, G-proteins comprise three dissimilar subunits; Gα, Gβ and Gγ. The Gα subunit consists of an α-helical and a GTPase domain, the latter is responsible for interaction with Gβγ, receptor and effector. Gβ and Gγ form a tightly associated heterodimer which can also modulate effector activity when released by the activated Gα. Genome sequence and other data suggest that, in plants, there are several (~8-10?) Gα, one or two Gβ and one Gγ. These proteins are expressed throughout the plant, mainly in the plasma membrane and endoplasmic reticulum. In vivo, there is strong evidence for G-protein control of ion channels, particularly K+ , in the response pathways to fungal and bacterial pathogens as well as in some aspects of gibberellin, abscisic acid and auxin signaling pathways. Finally, future prospects for understanding plant G-protein linked signaling will rely on new and emerging technologies; these include antisense suppression, gene knockouts, yeast two-hybrid and phage display molecular approaches, intracellular immunization using recombinant single chain antibodies and expression of peptide encoding minigenes.
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Affiliation(s)
- P A Millner
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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Abstract
A 67 year old man with longstanding rheumatoid disease was referred to the regional spinal surgery unit with acute onset of paraparesis due to an extensive spinal epidural abscess of the lumbar spine. Ten months previously, he had started antibiotic treatment at another hospital for an epidural abscess arising at the level of the L2-3 disc space. Despite completing seven months of medical treatment with appropriate antibiotics, he had a recrudescence of acute back pain shortly after restarting methotrexate treatment. Urgent anterior spinal decompression with excision of the necrotic vertebral bodies of L1-3 was performed. The indications for the surgical management of spinal epidural abscess are reviewed.
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Affiliation(s)
- P Harrington
- Spinal Surgery Unit, St James's University Hospital, Leeds, UK.
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44
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Doherty MJ, Millner PA, Latham M, Dickson RA, Elliott MW. Non-invasive ventilation in the treatment of ventilatory failure following corrective spinal surgery. Anaesthesia 2001; 56:235-8. [PMID: 11251430 DOI: 10.1046/j.1365-2044.2001.01422.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [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: 01/13/2023]
Abstract
Non-invasive positive pressure ventilation has previously been used successfully to treat both acute and chronic ventilatory failure secondary to a number of conditions, including scoliosis. We report two patients in whom it was used, on three separate occasions, to treat acute ventilatory failure following corrective spinal surgery. Non-invasive positive pressure ventilation may be useful postoperatively in high-risk patients undergoing major spinal surgery in an attempt to prevent intubation and its attendant complications.
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Affiliation(s)
- M J Doherty
- Department of Respiratory Medicine, St. James's University Hospital, Beckett Street, Leeds, UK
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45
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Abstract
Pectoralis major rupture is a well-recognised but uncommon injury that rarely leads to complications. We present an unusual case where the resultant haematoma following a partial rupture became infected and caused problems with diagnosis. We are only aware of one previous report of this.
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Affiliation(s)
- K Chapple
- Department of Orthopaedics, St. James' University Hospital, Leeds, UK
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46
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Abstract
Posterior fracture-dislocation of the hip is an uncommon injury in athletics and leisure activities. It is more commonly seen in high energy motor vehicle accidents and occasionally in high energy sporting activities. A rare case is reported of posterior fracture-dislocation of the hip joint that occurred in a young athlete during gymnastics. This unusual mechanism of injury illustrates the great forces sustained by the hip joint of gymnasts. Early reduction and operative treatment led to a congruent and stable hip joint. After rehabilitation, she returned to light sporting activities after six months.
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Affiliation(s)
- J C Mitchell
- Department of Trauma and Orthopaedics, St James's University Hospital, Leeds, United Kingdom
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47
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Abstract
Castleman's disease, angio-follicular lymph node hyperplasia, is a relatively rare benign tumour. It typically arises in the mediastinum. We report a unique case arising in the erector spinae muscle. The case demonstrates the importance of radiological investigation and embolisation prior to obtaining a tissue diagnosis and subsequent surgical excision.
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Affiliation(s)
- H R Williams
- Department of Trauma and Orthopaedics, St. James's University Hospital Trust, Leeds, UK
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48
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Wise A, Thomas PG, Carr TH, Murphy GA, Millner PA. Expression of the Arabidopsis G-protein GP alpha1: purification and characterisation of the recombinant protein. Plant Mol Biol 1997; 33:723-728. [PMID: 9132063 DOI: 10.1023/a:1005732423622] [Citation(s) in RCA: 8] [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] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The Arabidopsis G alpha subunit, GP alpha1, was expressed within Escherichia coli by co-transformation with the expression vector and the dnaY gene which encodes tRNA(Arg)(AGA/AGG) Isolation of the recombinant GP alpha1 in a highly pure form could be achieved by a combination of anion exchange and dye affinity chromatography or by a single step affinity procedure via chromatography on 4-amino-anilido-GTP agarose. The recombinant protein yielded by both procedures was highly active and bound GTPgammaS with an apparent Kd in the nM range. GTPgammaS binding was stimulated two-fold in the presence of Zn2+ compared with that in the presence of Mg2+, Mn2+ or Ca2+.
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Affiliation(s)
- A Wise
- Department of Biochemistry and Molecular Biology, University of Leeds, UK
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Abstract
For whatever reason, right-left asymmetry has attracted an illogical proportion of research effort. Non-structural scoliosis, for example secondary to a leg length inequality, is indeed a problem of right-left asymmetry, but structural scoliosis is a complex three-dimensional deformity involving all planes. Biomechanical, biological and clinical evidence indicates clearly that the problem is one of front-back asymmetry and not right-left. The importance of biological factors lies in their ability to bring the spinal column to and beyond its buckling threshold. Thus a taller and more slender spine is more liable to bend and, being stiffer in the sagittal plane, favours movement into other planes. This epitomises the spine of the scoliosis patient who is growing faster with a spinal template similar to other family members allowing idiopathic scoliosis to express itself genetically. It is the opposite condition to idiopathic hyperkyphosis (Scheuermann's disease), but this deformity is rotationally stable, thus remaining in the sagittal plane. The presence of an adjacent area of lordo-scoliosis below the region of hyperkyphosis testifies to the common nature of the pathogenesis of idiopathic scoliosis and Scheuermann's disease. It is the area of compensatory hyperlordosis below the Scheuermann's area that has obligatorily buckled and represents a human model supporting the lordosis theory, as does surgically tethering the back of the young growing human spine, which crankshafts accelerated progression. Similarly the only successful animal model of the formation of idopathic follows creation of a lordotic spinal segment in an otherwise kyphotic spine. For centuries, engineers have recognised that the mechanical behaviour of a column under load is influenced by geometry, as well as by material properties; it is clear that the spinal column also obeys these well-described laws.
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Affiliation(s)
- P A Millner
- Division of Orthopaedic Surgery, St. James's University Hospital, Leeds, UK
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Stirling AJ, Howel D, Millner PA, Sadiq S, Sharples D, Dickson RA. Late-onset idiopathic scoliosis in children six to fourteen years old. A cross-sectional prevalence study. J Bone Joint Surg Am 1996; 78:1330-6. [PMID: 8816647 DOI: 10.2106/00004623-199609000-00006] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.2] [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] [Indexed: 02/02/2023]
Abstract
We performed a point-prevalence survey of 15,799 children, six to fourteen years old, who formed part of a prospective longitudinal study. Our purpose was to detect the prevalence of scoliosis and to investigate associated factors. On the basis of the initial screening, 934 children (5.9 per cent) were referred for additional clinical and radiographic examinations; 896 children returned for this second evaluation. A lateral spinal curve with a Cobb angle of more than 5 degrees was seen in 431 children (2.7 per cent of the 15,799 children). Only seventy-six children (0.5 per cent) had a curve that met our definition of idiopathic scoliosis (a curve of more than 10 degrees with concordant apical rotation). The point-prevalence rate was higher in girls, and it increased with age. The rate was 0.1 per cent (four of 5246) in the age-group of six to eight years, 0.3 per cent (sixteen of 5831) in the age-group of nine to eleven years, and 1.2 per cent (fifty-six of 4722) in the age-group of twelve to fourteen years old. With allowance for the fact that different definitions of idiopathic scoliosis have been used in earlier studies, our results suggest that the natural history of idiopathic scoliosis may be becoming more benign spontaneously.
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