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Clennell B, Steward TGJ, Hanman K, Needham T, Benachour J, Jepson M, Elley M, Halford N, Heesom K, Shin E, Molnár E, Drinkwater BW, Whitcomb DJ. Ultrasound modulates neuronal potassium currents via ionotropic glutamate receptors. Brain Stimul 2023; 16:540-552. [PMID: 36731773 DOI: 10.1016/j.brs.2023.01.1674] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/27/2023] [Accepted: 01/27/2023] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Focused ultrasound stimulation (FUS) has the potential to provide non-invasive neuromodulation of deep brain regions with unparalleled spatial precision. However, the cellular and molecular consequences of ultrasound stimulation on neurons remains poorly understood. We previously reported that ultrasound stimulation induces increases in neuronal excitability that persist for hours following stimulation in vitro. In the present study we sought to further elucidate the molecular mechanisms by which ultrasound regulates neuronal excitability and synaptic function. OBJECTIVES To determine the effect of ultrasound stimulation on voltage-gated ion channel function and synaptic plasticity. METHODS Primary rat cortical neurons were exposed to a 40 s, 200 kHz pulsed ultrasound stimulus or sham-stimulus. Whole-cell patch clamp electrophysiology, quantitative proteomics and high-resolution confocal microscopy were employed to determine the effects of ultrasound stimulation on molecular regulators of neuronal excitability and synaptic function. RESULTS We find that ultrasound exposure elicits sustained but reversible increases in whole-cell potassium currents. In addition, we find that ultrasound exposure activates synaptic signalling cascades that result in marked increases in excitatory synaptic transmission. Finally, we demonstrate the requirement of ionotropic glutamate receptor (AMPAR/NMDAR) activation for ultrasound-induced modulation of neuronal potassium currents. CONCLUSION These results suggest specific patterns of pulsed ultrasound can induce contemporaneous enhancement of both neuronal excitability and synaptic function, with implications for the application of FUS in experimental and therapeutic settings. Further study is now required to deduce the precise molecular mechanisms through which these changes occur.
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Affiliation(s)
- Benjamin Clennell
- Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, BS1 3NY, UK
| | - Tom G J Steward
- Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, BS1 3NY, UK
| | - Kaliya Hanman
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Tom Needham
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Janette Benachour
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | - Mark Jepson
- Wolfson Bioimaging Facility, Faculty of Life Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Meg Elley
- Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, BS1 3NY, UK
| | - Nathan Halford
- Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, BS1 3NY, UK
| | - Kate Heesom
- Proteomics Facility Faculty of Life Sciences, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - Eunju Shin
- School of Life Sciences, Keele University, ST5 5BG, UK
| | - Elek Molnár
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, UK
| | | | - Daniel J Whitcomb
- Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, BS1 3NY, UK.
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Lorenc A, Wells M, Fulton-Lieuw T, Nankivell P, Mehanna H, Jepson M. Clinicians' Views of Patient-initiated Follow-up in Head and Neck Cancer: a Qualitative Study to Inform the PETNECK2 Trial. Clin Oncol (R Coll Radiol) 2022; 34:230-240. [PMID: 34862101 PMCID: PMC8950325 DOI: 10.1016/j.clon.2021.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/13/2021] [Accepted: 11/12/2021] [Indexed: 12/23/2022]
Abstract
AIMS Current follow-up for head and neck cancer (HNC) is ineffective, expensive and fails to address patients' needs. The PETNECK2 trial will compare a new model of patient-initiated follow-up (PIFU) with routine scheduled follow-up. This article reports UK clinicians' views about HNC follow-up and PIFU, to inform the trial design. MATERIALS AND METHODS Online focus groups with surgeons (ear, nose and throat/maxillofacial), oncologists, clinical nurse specialists and allied health professionals. Clinicians were recruited from professional bodies, mailing lists and personal contacts. Focus groups explored views on current follow-up and acceptability of the proposed PIFU intervention and randomised controlled trial design (presented by the study co-chief investigator), preferences, margins of equipoise, potential organisational barriers and thoughts about the content and format of PIFU. Data were interpreted using inductive thematic analysis. RESULTS Eight focus groups with 34 clinicians were conducted. Clinicians highlighted already known limitations with HNC follow-up - lack of flexibility to address the wide-ranging needs of HNC patients, expense and lack of evidence - and agreed that follow-up needs to change. They were enthusiastic about the PETNECK2 trial to develop and evaluate PIFU but had concerns that PIFU may not suit disengaged patients and may aggravate patient anxiety/fear of recurrence and delay detection of recurrence. Anticipated issues with implementation included ensuring a reliable route back to clinic and workload burden on nurses and allied health professionals. CONCLUSIONS Clinicians supported the evaluation of PIFU but voiced concerns about barriers to help-seeking. An emphasis on patient engagement, psychosocial issues, symptom reporting and reliable, quick routes back to clinic will be important. Certain patient groups may be less suited to PIFU, which will be evaluated in the trial. Early, meaningful, ongoing engagement with clinical teams and managers around the trial rationale and recruitment process will be important to discourage selective recruitment and address risk-averse behaviour and potential workload burden.
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Affiliation(s)
- A Lorenc
- QuinteT Research Group, Bristol Medical School, University of Bristol, Bristol, UK.
| | - M Wells
- Nursing Directorate, Imperial College Healthcare, NHS Trust / Department of Surgery and Oncology, Imperial College, London, London, UK
| | - T Fulton-Lieuw
- Institute of Head and Neck Studies and Education (InHANSE), Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - P Nankivell
- Institute of Head and Neck Studies and Education (InHANSE), Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK; University Hospitals, Birmingham NHS Foundation Trust, Birmingham, UK
| | - H Mehanna
- Institute of Head and Neck Studies and Education (InHANSE), Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK; University Hospitals, Birmingham NHS Foundation Trust, Birmingham, UK
| | - M Jepson
- QuinteT Research Group, Bristol Medical School, University of Bristol, Bristol, UK
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3
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Realpe AX, Foster NE, Dickenson EJ, Jepson M, Griffin DR, Donovan JL. Patient experiences of receiving arthroscopic surgery or personalised hip therapy for femoroacetabular impingement in the context of the UK fashion study: a qualitative study. Trials 2021; 22:211. [PMID: 33726810 PMCID: PMC7962311 DOI: 10.1186/s13063-021-05151-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 02/25/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND UK FASHIoN was a multicentre randomised controlled trial comparing hip arthroscopic surgery (HA) with personalised hip therapy (PHT, physiotherapist-led conservative care), for patients with hip pain attributed to femoroacetabular impingement (FAI) syndrome. Our aim was to describe the treatment and trial participation experiences of patients, to contextualise the trial results and offer further information to assist treatment decision-making in FAI. METHODS We conducted in-depth semi-structured telephone interviews with a purposive sample of trial participants from each of the trial arms. They were interviewed after they received treatment and completed their first year of trial participation. Thematic analysis and constant comparison analytical approaches were used to identify themes of patient treatment experiences during the trial. RESULTS Forty trial participants were interviewed in this qualitative study. Their baseline characteristics were similar to those in the main trial sample. On average, their hip-related quality of life (iHOT-33 scores) at 12 months follow-up were lower than average for all trial participants, indicating poorer hip-related quality of life as a consequence of theoretical sampling. Patient experiences occurred in five patient groups: those who felt their symptoms improved with hip arthroscopy, or with personal hip therapy, patients who felt their hip symptoms did not change with PHT but did not want HA, patients who decided to change from PHT to HA and a group who experienced serious complications after HA. Interviewees mostly described a trouble-free, enriching and altruistic trial participation experience, although most participants expected more clinical follow-up at the end of the trial. CONCLUSION Both HA and PHT were experienced as beneficial by participants in the trial. Treatment success appeared to depend partly on patients' prior own expectations as well as their outcomes, and future research is needed to explore this further. Findings from this study can be combined with the primary results to inform future FAI patients. TRIAL REGISTRATION Arthroscopic surgery for hip impingement versus best conventional care ( ISRCTN64081839 ). 28/02/2014.
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Affiliation(s)
- A X Realpe
- Population Health Sciences, University of Bristol, Canynge Hall 4.07, 39 Whatley Road, Bristol, BS8 2PS, UK.
| | - N E Foster
- Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, UK
| | - E J Dickenson
- University of Warwick, Coventry, UK
- University Hospitals of Coventry and Warwickshire NHS Trust, Coventry, UK
| | - M Jepson
- Population Health Sciences, University of Bristol, Canynge Hall 4.07, 39 Whatley Road, Bristol, BS8 2PS, UK
| | - D R Griffin
- University of Warwick, Coventry, UK
- University Hospitals of Coventry and Warwickshire NHS Trust, Coventry, UK
| | - J L Donovan
- Population Health Sciences, University of Bristol, Canynge Hall 4.07, 39 Whatley Road, Bristol, BS8 2PS, UK
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4
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Birchall M, Blazeby J, Blencowe N, Donovan J, Elliott D, Jepson M, Hutchinson P, Jayne D, Skilton A. Understanding risks, mitigation and innovation for surgery in a COVID-19 world. Br J Surg 2020; 107:e247. [PMID: 32410252 PMCID: PMC7272802 DOI: 10.1002/bjs.11691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 04/20/2020] [Indexed: 11/10/2022]
Affiliation(s)
- M Birchall
- Ear Institute, Faculty of Brain Sciences, UCL, London, UK
| | - J Blazeby
- NIHR Bristol Biomedical Research Centre, University Hospitals Bristol and Weston NHS Foundation Trust, Cambridge, UK.,Population Health Sciences, University of Bristol, Cambridge, UK
| | - N Blencowe
- Population Health Sciences, University of Bristol, Cambridge, UK
| | - J Donovan
- Population Health Sciences, University of Bristol, Cambridge, UK
| | - D Elliott
- Population Health Sciences, University of Bristol, Cambridge, UK
| | - M Jepson
- Population Health Sciences, University of Bristol, Cambridge, UK
| | - P Hutchinson
- Cambridge Neuroscience, University of Cambridge, Cambridge, UK
| | - D Jayne
- Faculty of Medicine and Health, School of Medicine, University of Leeds, Leeds, UK
| | - A Skilton
- Population Health Sciences, University of Bristol, Cambridge, UK
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5
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White J, Jepson M, McAuliffe S, Cridland K, Malliaris P, Haines T. “Patient education – you do not have the time not to do this”. A qualitative exploration of expert clinician attitudes of education in the management of rotator cuff tendinopathy. J Sci Med Sport 2019. [DOI: 10.1016/j.jsams.2019.08.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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6
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Dooley J, Armstrong RA, Jepson M, Squire Y, Hinchliffe RJ, Mouton R. Qualitative study of clinician and patient perspectives on the mode of anaesthesia for emergency surgery. Br J Surg 2019; 107:e142-e150. [PMID: 31368512 PMCID: PMC6973173 DOI: 10.1002/bjs.11243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 12/23/2022]
Abstract
Background Although delivering a chosen mode of anaesthesia for certain emergency surgery procedures is potentially beneficial to patients, it is a complex intervention to evaluate. This qualitative study explored clinician and patient perspectives about mode of anaesthesia for emergency surgery. Methods Snowball sampling was used to recruit participants from eight National Health Service Trusts that cover the following three emergency surgery settings: ruptured abdominal aortic aneurysms, hip fractures and inguinal hernias. A qualitative researcher conducted interviews with clinicians and patients. Thematic analysis was applied to the interview transcripts. Results Interviews were conducted with 21 anaesthetists, 21 surgeons, 14 operating theatre staff and 23 patients. There were two main themes. The first, impact of mode of anaesthesia in emergency surgery, had four subthemes assessing clinician and patient ideas about: context and the ‘best’ mode of anaesthesia; balance in choosing it over others; change and developments in anaesthesia; and the importance of mode of anaesthesia in emergency surgery. The second, tensions in decision‐making about mode of anaesthesia, comprised four subthemes: clinical autonomy and guidelines in anaesthesia; conforming to norms in mode of anaesthesia; the relationship between expertise, preference and patient involvement; and team dynamics in emergency surgery. The results highlight several interlinking factors affecting decision‐making, including expertise, preference, habit, practicalities, norms and policies. Conclusion There is variation in practice in choosing the mode of anaesthesia for surgery, alongside debate as to whether anaesthetic autonomy is necessary or results in a lack of willingness to change.
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Affiliation(s)
- J Dooley
- Department of Population Health Sciences, Bristol Medical School, Bristol, UK
| | - R A Armstrong
- Anaesthetic Department, Southmead Hospital, Bristol, UK
| | - M Jepson
- Department of Population Health Sciences, Bristol Medical School, Bristol, UK
| | - Y Squire
- Anaesthetic Department, Southmead Hospital, Bristol, UK
| | - R J Hinchliffe
- Bristol Surgical Trials Centre, Bristol Medical School, Bristol, UK
| | - R Mouton
- Anaesthetic Department, Southmead Hospital, Bristol, UK
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7
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Gulácsy CE, Meade R, Catici DAM, Soeller C, Pantos GD, Jones DD, Alibhai D, Jepson M, Valev VK, Mason JM, Williams RJ, Pudney CR. Excitation-Energy-Dependent Molecular Beacon Detects Early Stage Neurotoxic Aβ Aggregates in the Presence of Cortical Neurons. ACS Chem Neurosci 2019; 10:1240-1250. [PMID: 30346718 DOI: 10.1021/acschemneuro.8b00322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
There is now crucial medical importance placed on understanding the role of early stage, subvisible protein aggregation, particularly in neurodegenerative disease. While there are strategies for detecting such aggregates in vitro, there is no approach at present that can detect these toxic species associated with cells and specific subcellular compartments. We have exploited excitation-energy-dependent fluorescence edge-shift of recombinant protein labeled with a molecular beacon, to provide a sensitive read out for the presence of subvisible protein aggregates. To demonstrate the potential utility of the approach, we examine the major peptide associated with the initiation of Alzheimer's disease, amyloid β-protein (Aβ) at a patho-physiologically relevant concentration in mouse cortical neurons. Using our approach, we find preliminary evidence that subvisible Aβ aggregates are detected at specific subcellular regions and that neurons drive the formation of specific Aβ aggregate conformations. These findings therefore demonstrate the potential of a novel fluorescence-based approach for detecting and imaging protein aggregates in a cellular context, which can be used to sensitively probe the association of early stage toxic protein aggregates within subcellular compartments.
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Affiliation(s)
| | | | | | - Christian Soeller
- Biomedical Physics, University of Exeter, Exeter EX4 4QD, United Kingdom
| | | | - D. Dafydd Jones
- School of Biosciences, Cardiff University, Cardiff CF10 3TL, United Kingdom
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Mark Jepson
- Wolfson Bioimaging Facility, University of Bristol, Bristol BS8 1TS, United Kingdom
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8
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Heslop P, Marriott A, Hoghton M, Jepson M, Noble A. Caring for a woman with intellectual disabilities who refuses clinical diagnostic investigations. BMJ 2014. [DOI: 10.1136/bmj.f7645] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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9
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Jepson M, Liu X, Bell D, Ferranti D, Inkson B, Rodenburg C. Resolution limits of secondary electron dopant contrast in helium ion and scanning electron microscopy. Microsc Microanal 2011; 17:637-642. [PMID: 21745435 DOI: 10.1017/s1431927611000365] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
As the miniaturization of semiconductor devices continues, characterization of dopant distribution within the structures becomes increasingly challenging. One potential solution is the use of the secondary electron signal produced in scanning electron (SEMs) or helium ion microscopes (HeIMs) to image the changes in electrical potential caused by the dopant atoms. In this article, the contrast mechanisms and resolution limits of secondary electron dopant contrast are explored. It is shown that the resolution of the technique is dependent on the extent of electrical potential present at a junction and that the resolution of dopant contrast can be improved in the HeIM after an in-situ plasma cleaning routine, which causes an oxide to form on the surface altering the contrast mechanism from electrical potential to material contrast.
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Affiliation(s)
- Mark Jepson
- Department of Materials, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK.
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Abstract
Abstract
A survey carried out by the authors in the West Midlands area of England found that use of, and access to, community pharmaceutical services appeared to be lower among ethnic minority customers than in the majority population, although their needs were probably higher. The survey has been published in full elsewhere. In this article, the authors summarise the main results of their survey, and compare these with the results from a similar study involving respondents predominantly from the white population. They also discuss some of the methodological difficulties in carrying out research into ethnic minority health issues.
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Affiliation(s)
- J Jesson
- Pharmacy Practice Research Group, Institute of Pharmaceutical Sciences, Aston University, Birmingham, England B4 7ET
| | - S Sadler
- MEL Research, Aston Science Park, Birmingham
| | - R Pocock
- MEL Research, Aston Science Park, Birmingham
| | - M Jepson
- Pharmacy Practice Research Group, Institute of Pharmaceutical Sciences, Aston University, Birmingham, England B4 7ET
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11
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Scown TM, Santos EM, Johnston BD, Gaiser B, Baalousha M, Mitov S, Lead JR, Stone V, Fernandes TF, Jepson M, van Aerle R, Tyler CR. Effects of Aqueous Exposure to Silver Nanoparticles of Different Sizes in Rainbow Trout. Toxicol Sci 2010; 115:521-34. [DOI: 10.1093/toxsci/kfq076] [Citation(s) in RCA: 259] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Gaiser BK, Fernandes TF, Jepson M, Lead JR, Tyler CR, Stone V. Assessing exposure, uptake and toxicity of silver and cerium dioxide nanoparticles from contaminated environments. Environ Health 2009; 8 Suppl 1:S2. [PMID: 20102587 PMCID: PMC2796498 DOI: 10.1186/1476-069x-8-s1-s2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The aim of this project was to compare cerium oxide and silver particles of different sizes for their potential for uptake by aquatic species, human exposure via ingestion of contaminated food sources and to assess their resultant toxicity. The results demonstrate the potential for uptake of nano and larger particles by fish via the gastrointestinal tract, and by human intestinal epithelial cells, therefore suggesting that ingestion is a viable route of uptake into different organism types. A consistency was also shown in the sensitivity of aquatic, fish cell and human cell models to Ag and CeO2 particles of different sizes; with the observed sensitivity sequence from highest to lowest as: nano-Ag > micro Ag > nano CeO2 = micro CeO2. Such consistency suggests that further studies might allow extrapolation of results between different models and species.
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Affiliation(s)
- Birgit K Gaiser
- Edinburgh Napier University, Merchiston Campus, Edinburgh EH10 5DT, UK
| | | | - Mark Jepson
- Cell Imaging Facility and Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Jamie R Lead
- School of Geography, Earth and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Charles R Tyler
- Environmental and Molecular Fish Biology, The Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK
| | - Vicki Stone
- Edinburgh Napier University, Merchiston Campus, Edinburgh EH10 5DT, UK
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Dusinska M, Fjellsbo LM, Heimstad E, Harju M, Bartonova A, Tran L, Juillerat-Jeanneret L, Halamoda B, Marano F, Boland S, Saunders M, Cartwright L, Carreira S, Thawley S, Whelan M, Klein C, Housiadas C, Volkovova K, Tulinska J, Beno M, Sebekova K, Knudsen LE, Mose T, Castell JV, Vilà MR, Gombau L, Jepson M, Pojana G, Marcomini A. Development of methodology for alternative testing strategies for the assessment of the toxicological profile of nanoparticles used in medical diagnostics. NanoTEST – EC FP7 project. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/170/1/012039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Rollason R, Korolchuk V, Hamilton C, Jepson M, Banting G. A CD317/tetherin-RICH2 complex plays a critical role in the organization of the subapical actin cytoskeleton in polarized epithelial cells. ACTA ACUST UNITED AC 2009; 184:721-36. [PMID: 19273615 PMCID: PMC2686410 DOI: 10.1083/jcb.200804154] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CD317/tetherin is a lipid raft–associated integral membrane protein with a novel topology. It has a short N-terminal cytosolic domain, a conventional transmembrane domain, and a C-terminal glycosyl-phosphatidylinositol anchor. We now show that CD317 is expressed at the apical surface of polarized epithelial cells, where it interacts indirectly with the underlying actin cytoskeleton. CD317 is linked to the apical actin network via the proteins RICH2, EBP50, and ezrin. Knocking down expression of either CD317 or RICH2 gives rise to the same phenotype: a loss of the apical actin network with concomitant loss of apical microvilli, an increase in actin bundles at the basal surface, and a reduction in cell height without any loss of tight junctions, transepithelial resistance, or the polarized targeting of apical and basolateral membrane proteins. Thus, CD317 provides a physical link between lipid rafts and the apical actin network in polarized epithelial cells and is crucial for the maintenance of microvilli in such cells.
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Affiliation(s)
- Ruth Rollason
- Department of Biochemistry, University of Bristol, Bristol BS8 1TD, England, UK
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15
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Rempe D, Vangeison G, Hamilton J, Li Y, Jepson M, Federoff HJ. Synapsin I Cre transgene expression in male mice produces germline recombination in progeny. Genesis 2006; 44:44-9. [PMID: 16419044 DOI: 10.1002/gene.20183] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The cre/LoxP system can produce conditional loss of gene function in specific cell types such as neurons. A transgenic mouse line, utilized by multiple studies, used the Synapsin I promoter to drive expression of cre (SynCre) to achieve neuronal-specific cre expression. Herein we describe that cre expression can also be observed in SynCre mice within the testes after being bred into a floxed transgenic mouse line. Cre transcript was expressed in testes resulting in recombination of the floxed substrate in testes. In the majority of cases, progeny of male SynCre mice inherited a germline recombined floxed allele, while this was never observed in progeny from female mice carrying the SynCre allele. This observation should alert investigators to a potential confound using these mice and enables male germ cell "deletor" strategies.
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Pattni K, Jepson M, Stenmark H, Banting G. A PtdIns(3)P-specific probe cycles on and off host cell membranes during Salmonella invasion of mammalian cells. Curr Biol 2001; 11:1636-42. [PMID: 11676927 DOI: 10.1016/s0960-9822(01)00486-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Salmonella invade nonphagocytic cells by eliciting their own internalization; upon contact with the host cell, the bacteria induce membrane ruffles highly localized to the point of contact between the invading bacterium and the host cell. The bacterium is then internalized into an unusual cytosolic organelle, the Salmonella-containing vacuole (SCV). Early endosomal markers (including EEA1) have recently been shown to be associated with the SCV shortly after invasion. EEA1, a protein involved in early endosome fusion, is recruited to early endosomal membranes in part by the interaction between its FYVE finger and phosphatidylinositol 3-phosphate [PtdIns(3)P], a characteristic lipid of early endosomes. This suggests a possible role for PtdIns(3)P during Salmonella infection. To investigate this, we generated a highly specific probe for PtdIns(3)P that was used to follow invasion of Salmonella in nonphagocytic cells. Here, we show that PtdIns(3)P is present on the membranes of SCVs shortly after invasion and also that it is present on the membrane ruffles produced immediately prior to invasion. We also show that this specific probe cycles on and off the membranes of nascent SCVs even when PtdIns 3-kinase activity is inhibited, demonstrating that invading Salmonella influence the composition of the membranes that envelop them during invasion.
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Affiliation(s)
- K Pattni
- Department of Biochemistry, University of Bristol, Bristol, United Kingdom
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Jepson M, Bullifent HL, Crane D, Flores-Diaz M, Alape-Giron A, Jayasekeera P, Lingard B, Moss D, Titball RW. Tyrosine 331 and phenylalanine 334 in Clostridium perfringens alpha-toxin are essential for cytotoxic activity. FEBS Lett 2001; 495:172-7. [PMID: 11334886 DOI: 10.1016/s0014-5793(01)02385-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [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: 11/29/2022]
Abstract
Differences in the biological properties of the Clostridium perfringens phospholipase C (alpha-toxin) and the C. bifermentans phospholipase C (Cbp) have been attributed to differences in their carboxy-terminal domains. Three residues in the carboxy-terminal domain of alpha-toxin, which have been proposed to play a role in membrane recognition (D269, Y331 and F334), are not conserved in Cbp (Y, L and I respectively). We have characterised D269Y, Y331L and F334I variant forms of alpha-toxin. Variant D269Y had reduced phospholipase C activity towards aggregated egg yolk phospholipid but increased haemolytic and cytotoxic activity. Variants Y331L and F334I showed a reduction in phospholipase C, haemolytic and cytotoxic activities indicating that these substitutions contribute to the reduced haemolytic and cytotoxic activity of Cbp.
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Affiliation(s)
- M Jepson
- Defense Evaluation Research Agency, CBD Porton Down, Salisbury, UK
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19
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Abstract
Many Gram-negative pathogens use a type III secretion apparatus to deliver effector molecules into host cells to subvert cellular processes in favour of the pathogen. Enteropathogenic Escherichia coli (EPEC) uses such a system to deliver the Tir effector molecule into host cells. In this paper, we show that the gene upstream of tir, orf19, encodes an additional type III secreted effector protein. Orf19 is delivered into host cells by a mechanism independent of endocytosis, but dependent on EspB. Orf19 is targeted to host mitochondria, where it appears to interfere with the ability to maintain membrane potential. Although the precise role of Orf19 remains to be elucidated, its interaction with mitochondria suggests a possible role in the subversion of key functions of these organelles, such as energy production or control of cell death. This is the first example of a type III secreted protein targeted to mitochondria; it is probable that homologues (present in EPEC and Shigella species) and other bacterial effectors will also target this organelle.
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Affiliation(s)
- B Kenny
- Department of Pathology and Microbiology, School of Medical Sciences, University Walk, Bristol, UK.
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20
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Abstract
A range of clostridial species produce phospholipases C. The zinc metallo phospholipases C have related sequences but different properties. All of these enzymes may be arranged, like alpha-toxin as two-domain proteins. Differences in enzymatic, haemolytic and toxic properties may be explained by differences in amino acids at key positions.
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Affiliation(s)
- M Jepson
- Defence Evaluation and Research Agency, CBD, Porton Down, Salisbury, Wiltshire SP4 0JQ, UK
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21
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Naylor CE, Jepson M, Crane DT, Titball RW, Miller J, Basak AK, Bolgiano B. Characterisation of the calcium-binding C-terminal domain of Clostridium perfringens alpha-toxin. J Mol Biol 1999; 294:757-70. [PMID: 10610794 DOI: 10.1006/jmbi.1999.3279] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Alpha-toxin is the key determinant in gas-gangrene. The toxin, a phospholipase C, cleaves phosphatidylcholine in eukaryotic cell membranes. Calcium ions have been shown to be required for the specific binding of toxin to membranes prior to phospholipid cleavage. Reported X-ray crystallographic structures of the toxin show that the C-terminal domain has a fold that is analogous to the eukaryotic calcium and membrane-binding C2 domains. We report the binding sites for three calcium ions that have been identified, by crystallographic methods, in the C-terminal domain of the protein close to the postulated membrane-binding surface. The position of these ions at the tip of the domain, and their function (to facilitate membrane binding) is similar to that of calcium ions observed bound to C2 domains. Using the optical spectroscopic techniques of circular dichroism (CD) and fluorescence spectroscopy, pronounced changes to both near and far-UV CD and tryptophan emission fluorescence upon addition of calcium to the C-terminal domain of alpha-toxin have been observed. The changes in near-UV CD, fluorescence enhancement and a 2 nm blue-shift in the fluorescence emission spectrum are consistent with tryptophan residue(s) becoming more immobilised in a hydrophobic environment. Calcium binding appears to be low-affinity: Kd approximately 175-250 microM at pH 8 assuming a 1:1 stoichiometry. as measured by spectroscopic methods.
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Affiliation(s)
- C E Naylor
- Department of Crystallography, Birkbeck College, London, UK
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22
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Jepson M, Howells A, Bullifent HL, Bolgiano B, Crane D, Miller J, Holley J, Jayasekera P, Titball RW. Differences in the carboxy-terminal (Putative phospholipid binding) domains of Clostridium perfringens and Clostridium bifermentans phospholipases C influence the hemolytic and lethal properties of these enzymes. Infect Immun 1999; 67:3297-301. [PMID: 10377104 PMCID: PMC116509 DOI: 10.1128/iai.67.7.3297-3301.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [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: 11/20/2022] Open
Abstract
The phospholipases C of C. perfringens (alpha-toxin) and C. bifermentans (Cbp) show >50% amino acid homology but differ in their hemolytic and toxic properties. We report here the purification and characterisation of alpha-toxin and Cbp. The phospholipase C activity of alpha-toxin and Cbp was similar when tested with phosphatidylcholine in egg yolk or in liposomes. However, the hemolytic activity of alpha-toxin was more than 100-fold that of Cbp. To investigate whether differences in the carboxy-terminal domains of these proteins were responsible for differences in the hemolytic and toxic properties, a hybrid protein (NbiCalpha) was constructed comprising the N domain of Cbp and the C domain of alpha-toxin. The hemolytic activity of NbiCalpha was 10-fold that of Cbp, and the hybrid enzyme was toxic. These results confirm that the C-terminal domain of these proteins confers different properties on the enzymatically active N-terminal domain of these proteins.
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Affiliation(s)
- M Jepson
- Defence Evaluation and Research Agency, CBD Porton Down, Salisbury, Wiltshire SP4 0JQ, United Kingdom
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23
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Abstract
This is a discussion paper which generates some important research questions for educationalists. The teaching of food skills are at danger of being lost from the school cirriculum by changes imposed by the National Curriculum. This sinister (i.e., unexplained/undefined) development generates potential problems for the teaching of cookery and for the food and eating traditions of British society. The central concern for nutrition educationalists is that cooking is becoming more and more de-domesticated and consequently will become more systemised, more mass produced; in which case, young people need not be educated in basic cooking skills.
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Affiliation(s)
- S Stitt
- Centre for Consumer Education & Research, Liverpool John Moores University, IM Marsh
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24
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Blenkinsopp A, Jepson M, Drury M. Using a notification card to improve communication between community pharmacists and general practitioners. Br J Gen Pract 1991; 41:116-8. [PMID: 2031755 PMCID: PMC1371625] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A pilot scheme was set up to evaluate a notification card to be used by community pharmacists when referring patients to their general practitioner, with the aim of improving communication. Six community pharmacists and 15 general practitioners took part in the study. During the 18 month study period 120 cards were issued by pharmacists. The majority of patients (71%) advised to see their general practitioner by the pharmacist did so. Fourteen cards (12%) were issued for suspected adverse drug reactions. The card was received positively by patients, doctors and pharmacists.
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Affiliation(s)
- A Blenkinsopp
- Pharmacy Practice Research Unit, Bradford University
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25
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Abstract
In an outbreak of Salmonella ealing infections in November and December, 1985, the proportion of infants infected was in excess of the normal distribution pattern and the cases were geographically widespread. All the infected infants had been fed with a dried-milk product from one manufacturer. Despite intensive efforts to isolate S ealing from packets of the product, it was found only in low numbers in 4 of 267 sealed packets. The source of infection was traced to the factory spray-drier, which had a hole in its inner lining, allowing escape of powder and its return from contaminated insulation material. The plant was closed and the equipment scrapped and later replaced. It is recommended that raw milk and whey, which frequently contain salmonellae, should not be allowed onto the site of milk-drying plants.
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Affiliation(s)
- B Rowe
- Central Public Health Laboratory, Colindale, London
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26
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Powers HJ, Bates CJ, Prentice AM, Lamb WH, Jepson M, Bowman H. The relative effectiveness of iron and iron with riboflavin in correcting a microcytic anaemia in men and children in rural Gambia. Hum Nutr Clin Nutr 1983; 37:413-425. [PMID: 6668226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Adult males and children between 4 and 12 years in a subsistence farming community in The Gambia were screened for haematological status. 80 men and 80 children with initially poor status were identified and allocated to three treatment groups comprising: a placebo, ferrous sulphate, and ferrous sulphate with riboflavin. Over a period of 6 weeks of supplementation there was a general improvement in haematological status in the two supplemented groups. The inclusion of riboflavin in the supplement enhanced recovery, particularly in those individuals with strikingly low levels of haemoglobin at the outset.
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27
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Ford J, Jepson M, Bryman A, Keil T, Bresnen M, Beardsworth A. Management of recruitment in the construction industry. International Journal of Project Management 1983. [DOI: 10.1016/0263-7863(83)90003-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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28
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Carpenter RG, Gardner A, Jepson M, Taylor EM, Salvin A, Sunderland R, Emery JL, Pursall E, Roe J. Prevention of unexpected infant death. Evaluation of the first seven years of the Sheffield Intervention Programme. Lancet 1983; 1:723-7. [PMID: 6132080 DOI: 10.1016/s0140-6736(83)92023-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the years 1973-79, 39452 infants born to parents resident in Sheffield were scored at birth for risk of unexpected infant death. Before 1973 post-perinatal mortality in Sheffield was on average 11.5% above the rate for England and Wales. Since 1973 it has only once exceeded the rate for England and Wales. "Possibly preventable" deaths have fallen from 5.2 to 1.9 per 1000. 12% of this decline is associated with a rise in the average age of the mother and a fall in the number of pregnancies, 9% with a reduction in precipitate deliveries, 24% with an increase in breastfeeding, 18% with extra care given by health visitors to high-risk infants, and 36% with other factors. The reduction in mortality attributed directly to the effect of increased visiting of high-risk infants is numerically similar to the number of lives saved by treating cancers of children. This suggests that home visiting by health visitors is highly cost-effective.
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29
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Affiliation(s)
- M Jepson
- Lately Specialist in Community Medicine (Child Health), Sheffield Health Authority
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