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Kumar J, Liddle EB, Fernandes CC, Palaniyappan L, Hall EL, Robson SE, Simmonite M, Fiesal J, Katshu MZ, Qureshi A, Skelton M, Christodoulou NG, Brookes MJ, Morris PG, Liddle PF. Glutathione and glutamate in schizophrenia: a 7T MRS study. Mol Psychiatry 2020; 25:873-882. [PMID: 29934548 PMCID: PMC7156342 DOI: 10.1038/s41380-018-0104-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 05/04/2018] [Accepted: 05/14/2018] [Indexed: 12/21/2022]
Abstract
In schizophrenia, abnormal neural metabolite concentrations may arise from cortical damage following neuroinflammatory processes implicated in acute episodes. Inflammation is associated with increased glutamate, whereas the antioxidant glutathione may protect against inflammation-induced oxidative stress. We hypothesized that patients with stable schizophrenia would exhibit a reduction in glutathione, glutamate, and/or glutamine in the cerebral cortex, consistent with a post-inflammatory response, and that this reduction would be most marked in patients with "residual schizophrenia", in whom an early stage with positive psychotic symptoms has progressed to a late stage characterized by long-term negative symptoms and impairments. We recruited 28 patients with stable schizophrenia and 45 healthy participants matched for age, gender, and parental socio-economic status. We measured glutathione, glutamate and glutamine concentrations in the anterior cingulate cortex (ACC), left insula, and visual cortex using 7T proton magnetic resonance spectroscopy (MRS). Glutathione and glutamate were significantly correlated in all three voxels. Glutamine concentrations across the three voxels were significantly correlated with each other. Principal components analysis (PCA) produced three clear components: an ACC glutathione-glutamate component; an insula-visual glutathione-glutamate component; and a glutamine component. Patients with stable schizophrenia had significantly lower scores on the ACC glutathione-glutamate component, an effect almost entirely leveraged by the sub-group of patients with residual schizophrenia. All three metabolite concentration values in the ACC were significantly reduced in this group. These findings are consistent with the hypothesis that excitotoxicity during the acute phase of illness leads to reduced glutathione and glutamate in the residual phase of the illness.
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Affiliation(s)
- Jyothika Kumar
- 0000 0004 1936 8868grid.4563.4Division of Psychiatry and Applied Psychology, University of Nottingham, Nottingham, UK
| | - Elizabeth B. Liddle
- 0000 0004 1936 8868grid.4563.4Division of Psychiatry and Applied Psychology, University of Nottingham, Nottingham, UK
| | - Carolina C. Fernandes
- 0000 0004 1936 8868grid.4563.4Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Lena Palaniyappan
- 0000 0004 1936 8884grid.39381.30Departments of Psychiatry, Medical Biophysics and Neuroscience, Western University, London, ON Canada ,Lawson Research, Brain and Mind & Robarts Research Institutes, London, ON Canada
| | - Emma L. Hall
- 0000 0004 1936 8868grid.4563.4Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Siân E. Robson
- 0000 0000 8610 2323grid.482042.8Healthcare Improvement Scotland, Gyle Square, Edinburgh, UK
| | - Molly Simmonite
- 0000000086837370grid.214458.eDepartment of Psychology, University of Michigan, Ann Arbor, MI USA
| | - Jan Fiesal
- grid.500956.fSouth Staffordshire and Shropshire Healthcare NHS Foundation Trust, Stafford, UK
| | - Mohammad Z. Katshu
- 0000 0004 1936 8868grid.4563.4Division of Psychiatry and Applied Psychology, University of Nottingham, Nottingham, UK ,0000 0001 1514 761Xgrid.439378.2Nottinghamshire Healthcare NHS Foundation Trust, Nottingham, UK
| | - Ayaz Qureshi
- 0000 0004 0430 6955grid.450837.dGreater Manchester West Mental Health NHS Foundation Trust, Manchester, UK
| | - Michael Skelton
- 0000 0004 0396 1667grid.418388.eDerbyshire Healthcare NHS Foundation Trust, Derby, UK
| | - Nikolaos G. Christodoulou
- 0000 0004 1936 8868grid.4563.4Division of Psychiatry and Applied Psychology, University of Nottingham, Nottingham, UK ,0000 0001 1514 761Xgrid.439378.2Nottinghamshire Healthcare NHS Foundation Trust, Nottingham, UK
| | - Matthew J. Brookes
- 0000 0004 1936 8868grid.4563.4Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Peter G. Morris
- 0000 0004 1936 8868grid.4563.4Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - Peter F. Liddle
- 0000 0004 1936 8868grid.4563.4Division of Psychiatry and Applied Psychology, University of Nottingham, Nottingham, UK
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Hall EL, Baines S, Bilmont A, Oxley B. Accuracy of patient-specific three-dimensional-printed osteotomy and reduction guides for distal femoral osteotomy in dogs with medial patella luxation. Vet Surg 2018; 48:584-591. [PMID: 30446995 DOI: 10.1111/vsu.13126] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 09/16/2018] [Accepted: 10/06/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To compare precorrectional and postcorrectional femoral alignment following distal femoral osteotomy using patient-specific 3-dimensional (3D)-printed osteotomy and reduction guides in vivo and ex vivo. STUDY DESIGN Prospective study. SAMPLE POPULATION Ten client-owned dogs and matching 3D-printed plastic bone models. METHODS Distal femoral osteotomy was performed via a standard approach using osteotomy and reduction guides developed with computer-aided design software prior to 3D-printing. Femoral osteotomy and reduction was also performed on 3D-printed models of each femur with identical reprinted guides. Femoral varus angle (FVA) and femoral torsion angle (FTA) were measured on postoperative computed tomographic images by 3 observers. RESULTS In vivo, the mean difference between target and achieved postoperative was 2.29° (±2.29°, P = .0076) for the FVA, and 1.67° (±2.08°, P = .300) for the FTA. Ex vivo, the mean difference between target and achieved postoperative was 0.29° (±1.50°, P = .813) for the FVA, and -2.33° (±3.21°, P = .336) for the FTA. Intraobserver intraclass correlation coefficients (ICC; 0.736-0.998) and interobserver ICC (0.829 to 0.996) were consistent with an excellent agreement. CONCLUSION Use of 3D-printed osteotomy and reduction guides allowed accurate correction of FTA in vivo and both FVA and FTA ex vivo. CLINICAL SIGNIFICANCE Use of 3D-printed osteotomy and reduction guides may improve the accuracy of correction of femoral alignment but warrant further evaluation of surgical time, perioperative complications, and patient outcomes compared with conventional techniques.
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Affiliation(s)
- Emma L Hall
- Willows Veterinary Centre and Referral Service, England, United Kingdom
| | - Stephen Baines
- Willows Veterinary Centre and Referral Service, England, United Kingdom
| | - Alexis Bilmont
- Willows Veterinary Centre and Referral Service, England, United Kingdom
| | - Bill Oxley
- Willows Veterinary Centre and Referral Service, England, United Kingdom
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Hall EL, Baines EA, Baines SJ. Atypical lateral tracheal collapse in a Yorkshire terrier. J Small Anim Pract 2018; 61:644-647. [PMID: 30387494 DOI: 10.1111/jsap.12954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/30/2018] [Accepted: 07/05/2018] [Indexed: 11/29/2022]
Abstract
A 10-month-old, neutered female Yorkshire terrier was presented with a 6-month history of inspiratory dyspnoea, coughing and exercise intolerance. Tracheoscopy revealed marked lateral-to-lateral fixed collapse of the cervical trachea and mild collapse of the thoracic trachea. Surgical exploration revealed a marked reduction in lateral tracheal width and multiple malformed tracheal rings. Placement of extraluminal ring prostheses around the cervical trachea resulted in widening of the tracheal diameter and an immediate improvement in clinical signs. 6 years postoperatively the patient was reported to have an excellent quality of life with complete resolution of clinical signs.
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Affiliation(s)
- E L Hall
- Department of Soft Tissue Surgery, Willows Veterinary Centre and Referral Service, Solihull, West Midlands, B90 4NH, UK
| | - E A Baines
- Department of Diagnostic Imaging, Willows Veterinary Centre and Referral Service, Solihull, West Midlands, B90 4NH, UK
| | - S J Baines
- Department of Soft Tissue Surgery, Willows Veterinary Centre and Referral Service, Solihull, West Midlands, B90 4NH, UK
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Brookes MJ, Groom MJ, Liuzzi L, Hill RM, Smith HJF, Briley PM, Hall EL, Hunt BAE, Gascoyne LE, Taylor MJ, Liddle PF, Morris PG, Woolrich MW, Liddle EB. Altered temporal stability in dynamic neural networks underlies connectivity changes in neurodevelopment. Neuroimage 2018; 174:563-575. [PMID: 29524625 DOI: 10.1016/j.neuroimage.2018.03.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/02/2018] [Accepted: 03/03/2018] [Indexed: 01/02/2023] Open
Abstract
Network connectivity is an integral feature of human brain function, and characterising its maturational trajectory is a critical step towards understanding healthy and atypical neurodevelopment. Here, we used magnetoencephalography (MEG) to investigate both stationary (i.e. time averaged) and rapidly modulating (dynamic) electrophysiological connectivity, in participants aged from mid-childhood to early adulthood (youngest participant 9 years old; oldest participant 25 years old). Stationary functional connectivity (measured via inter-regional coordination of neural oscillations) increased with age in the alpha and beta frequency bands, particularly in bilateral parietal and temporo-parietal connections. Our dynamic analysis (also applied to alpha/beta oscillations) revealed the spatiotemporal signatures of 8 dynamic networks; these modulate on a ∼100 ms time scale, and temporal stability in attentional networks was found to increase with age. Significant overlap was found between age-modulated dynamic networks and inter-regional oscillatory coordination, implying that altered network dynamics underlie age related changes in functional connectivity. Our results provide novel insights into brain network electrophysiology, and lay a foundation for future work in childhood disorders.
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Affiliation(s)
- Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
| | - Madeleine J Groom
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham, UK
| | - Lucrezia Liuzzi
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Ryan M Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Helen J F Smith
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham, UK
| | - Paul M Briley
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham, UK
| | - Emma L Hall
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Benjamin A E Hunt
- Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada; Neurosciences and Mental Health Program, The Hospital for Sick Children Research Institute, Toronto M5G0A4, Canada
| | - Lauren E Gascoyne
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Margot J Taylor
- Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada; Department of Medical Imaging, University of toronto, Toronto M5T1W7, Canada
| | - Peter F Liddle
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham, UK
| | - Peter G Morris
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Mark W Woolrich
- Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, United Kingdom
| | - Elizabeth B Liddle
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham, UK
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Barratt EL, Tewarie PK, Clarke MA, Hall EL, Gowland PA, Morris PG, Francis ST, Evangelou N, Brookes MJ. Abnormal task driven neural oscillations in multiple sclerosis: A visuomotor MEG study. Hum Brain Mapp 2017; 38:2441-2453. [PMID: 28240392 PMCID: PMC6866959 DOI: 10.1002/hbm.23531] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/20/2016] [Accepted: 01/17/2017] [Indexed: 01/14/2023] Open
Abstract
Multiple sclerosis (MS) is a debilitating disease commonly attributed to degradation of white matter myelin. Symptoms include fatigue, as well as problems associated with vision and movement. Although areas of demyelination in white matter are observed routinely in patients undergoing MRI scans, such measures are often a poor predictor of disease severity. For this reason, it is instructive to measure associated changes in brain function. Widespread white‐matter demyelination may lead to delays of propagation of neuronal activity, and with its excellent temporal resolution, magnetoencephalography can be used to probe such delays in controlled conditions (e.g., during a task). In healthy subjects, responses to visuomotor tasks are well documented: in motor cortex, movement elicits a localised decrease in the power of beta band oscillations (event‐related beta desynchronisation) followed by an increase above baseline on movement cessation (post‐movement beta rebound (PMBR)). In visual cortex, visual stimulation generates increased gamma oscillations. In this study, we use a visuomotor paradigm to measure these responses in MS patients and compare them to age‐ and gender‐matched healthy controls. We show a significant increase in the time‐to‐peak of the PMBR in patients which correlates significantly with the symbol digit modalities test: a measure of information processing speed. A significant decrease in the amplitude of visual gamma oscillations in patients is also seen. These findings highlight the potential value of electrophysiological imaging in generating a new understanding of visual disturbances and abnormal motor control in MS patients. Hum Brain Mapp 38:2441–2453, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Eleanor L Barratt
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Prejaas K Tewarie
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Margareta A Clarke
- Division of Clinical Neurology, Queen's Medical Centre, University of Nottingham, Nottingham, NG7 2UH, United Kingdom
| | - Emma L Hall
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Penny A Gowland
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Peter G Morris
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Nikos Evangelou
- Division of Clinical Neurology, Queen's Medical Centre, University of Nottingham, Nottingham, NG7 2UH, United Kingdom
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
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Hall EL, Guevar J, Holmes KL, Gutierrez-Quintana R. Conservative management of an atlantoaxial subluxation using thermoplastic material. J Small Anim Pract 2016; 57:386. [PMID: 27385625 DOI: 10.1111/jsap.12488] [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] [Received: 08/07/2015] [Revised: 01/19/2016] [Accepted: 01/22/2016] [Indexed: 11/29/2022]
Affiliation(s)
- E L Hall
- School of Veterinary Medicine, College of Medicine, Veterinary and Life Sciences, Glasgow University, Bearsden Road, Glasgow, G611QH
| | - J Guevar
- School of Veterinary Medicine, College of Medicine, Veterinary and Life Sciences, Glasgow University, Bearsden Road, Glasgow, G611QH
| | - K L Holmes
- School of Veterinary Medicine, College of Medicine, Veterinary and Life Sciences, Glasgow University, Bearsden Road, Glasgow, G611QH
| | - R Gutierrez-Quintana
- School of Veterinary Medicine, College of Medicine, Veterinary and Life Sciences, Glasgow University, Bearsden Road, Glasgow, G611QH
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Liddle EB, Price D, Palaniyappan L, Brookes MJ, Robson SE, Hall EL, Morris PG, Liddle PF. Abnormal salience signaling in schizophrenia: The role of integrative beta oscillations. Hum Brain Mapp 2016; 37:1361-74. [PMID: 26853904 PMCID: PMC4790909 DOI: 10.1002/hbm.23107] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 12/11/2015] [Accepted: 12/19/2015] [Indexed: 01/24/2023] Open
Abstract
Aberrant salience attribution and cerebral dysconnectivity both have strong evidential support as core dysfunctions in schizophrenia. Aberrant salience arising from an excess of dopamine activity has been implicated in delusions and hallucinations, exaggerating the significance of everyday occurrences and thus leading to perceptual distortions and delusional causal inferences. Meanwhile, abnormalities in key nodes of a salience brain network have been implicated in other characteristic symptoms, including the disorganization and impoverishment of mental activity. A substantial body of literature reports disruption to brain network connectivity in schizophrenia. Electrical oscillations likely play a key role in the coordination of brain activity at spatially remote sites, and evidence implicates beta band oscillations in long‐range integrative processes. We used magnetoencephalography and a task designed to disambiguate responses to relevant from irrelevant stimuli to investigate beta oscillations in nodes of a network implicated in salience detection and previously shown to be structurally and functionally abnormal in schizophrenia. Healthy participants, as expected, produced an enhanced beta synchronization to behaviorally relevant, as compared to irrelevant, stimuli, while patients with schizophrenia showed the reverse pattern: a greater beta synchronization in response to irrelevant than to relevant stimuli. These findings not only support both the aberrant salience and disconnectivity hypotheses, but indicate a common mechanism that allows us to integrate them into a single framework for understanding schizophrenia in terms of disrupted recruitment of contextually appropriate brain networks. Hum Brain Mapp 37:1361‐1374, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Elizabeth B Liddle
- Institute of Mental Health, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Darren Price
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Lena Palaniyappan
- Institute of Mental Health, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Siân E Robson
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Emma L Hall
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Peter G Morris
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, United Kingdom
| | - Peter F Liddle
- Institute of Mental Health, School of Medicine, University of Nottingham, Nottingham, United Kingdom
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Robson SE, Brookes MJ, Hall EL, Palaniyappan L, Kumar J, Skelton M, Christodoulou NG, Qureshi A, Jan F, Katshu MZ, Liddle EB, Liddle PF, Morris PG. Abnormal visuomotor processing in schizophrenia. Neuroimage Clin 2015; 12:869-878. [PMID: 27872809 PMCID: PMC5107643 DOI: 10.1016/j.nicl.2015.08.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 11/30/2022]
Abstract
Subtle disturbances of visual and motor function are known features of schizophrenia and can greatly impact quality of life; however, few studies investigate these abnormalities using simple visuomotor stimuli. In healthy people, electrophysiological data show that beta band oscillations in sensorimotor cortex decrease during movement execution (event-related beta desynchronisation (ERBD)), then increase above baseline for a short time after the movement (post-movement beta rebound (PMBR)); whilst in visual cortex, gamma oscillations are increased throughout stimulus presentation. In this study, we used a self-paced visuomotor paradigm and magnetoencephalography (MEG) to contrast these responses in patients with schizophrenia and control volunteers. We found significant reductions in the peak-to-peak change in amplitude from ERBD to PMBR in schizophrenia compared with controls. This effect was strongest in patients who made fewer movements, whereas beta was not modulated by movement in controls. There was no significant difference in the amplitude of visual gamma between patients and controls. These data demonstrate that clear abnormalities in basic sensorimotor processing in schizophrenia can be observed using a very simple MEG paradigm. Visual and motor deficits in schizophrenia are rarely investigated. We use MEG to non-invasively assess the neural basis of these deficits. Patients showed abnormalities in neuronal oscillations in motor cortex. Beta band power, reflecting cortical inhibition, was reduced after movements. Increased movement frequency may be a behavioural compensation for this reduction.
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Affiliation(s)
- Siân E Robson
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Emma L Hall
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Lena Palaniyappan
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Jyothika Kumar
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Michael Skelton
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Nikolaos G Christodoulou
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Ayaz Qureshi
- Kevin White Unit, Smithdown Health Park, Smithdown Road, Liverpool L15 2HE, UK
| | - Fiesal Jan
- Herschel Prins Centre, Glenfield Hospital, Leicestershire Partnership NHS Trust, Groby Road, Leicester LE3 9QP, UK
| | - Mohammad Z Katshu
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Elizabeth B Liddle
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Peter F Liddle
- Centre for Translational Neuroimaging in Mental Health, Institute of Mental Health, School of Medicine, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham NG7 2TU, UK
| | - Peter G Morris
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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Croal PL, Hall EL, Driver ID, Brookes MJ, Gowland PA, Francis ST. The effect of isocapnic hyperoxia on neurophysiology as measured with MRI and MEG. Neuroimage 2015; 105:323-31. [DOI: 10.1016/j.neuroimage.2014.10.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/27/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022] Open
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Hall EL, Robson SE, Morris PG, Brookes MJ. The relationship between MEG and fMRI. Neuroimage 2014; 102 Pt 1:80-91. [DOI: 10.1016/j.neuroimage.2013.11.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 09/12/2013] [Accepted: 11/04/2013] [Indexed: 10/26/2022] Open
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Brookes MJ, O'Neill GC, Hall EL, Woolrich MW, Baker A, Palazzo Corner S, Robson SE, Morris PG, Barnes GR. Measuring temporal, spectral and spatial changes in electrophysiological brain network connectivity. Neuroimage 2014; 91:282-99. [PMID: 24418505 DOI: 10.1016/j.neuroimage.2013.12.066] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 12/27/2013] [Accepted: 12/31/2013] [Indexed: 11/16/2022] Open
Affiliation(s)
- Matthew J Brookes
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, UK.
| | - George C O'Neill
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, UK
| | - Emma L Hall
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, UK
| | - Mark W Woolrich
- Oxford Centre for Human Brain Activity, University of Oxford, Warneford Hospital, Oxford, UK; Oxford Centre for Functional MRI of the Brain, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Adam Baker
- Oxford Centre for Human Brain Activity, University of Oxford, Warneford Hospital, Oxford, UK
| | - Sofia Palazzo Corner
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, UK
| | - Siân E Robson
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, UK
| | - Peter G Morris
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, UK
| | - Gareth R Barnes
- Wellcome Trust Centre for Neuroimaging, University College London, London, UK
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Hall EL, Stephenson MC, Price D, Morris PG. Methodology for improved detection of low concentration metabolites in MRS: optimised combination of signals from multi-element coil arrays. Neuroimage 2013; 86:35-42. [PMID: 23639258 DOI: 10.1016/j.neuroimage.2013.04.077] [Citation(s) in RCA: 49] [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: 01/30/2013] [Revised: 04/16/2013] [Accepted: 04/17/2013] [Indexed: 01/08/2023] Open
Abstract
State of the art magnetic resonance imaging (MRI) scanners are generally equipped with multi-element receive coils; 16 or 32 channel coils are common. Their development has been predominant for parallel imaging to enable faster scanning. Less consideration has been given to localized magnetic resonance spectroscopy (MRS). Multinuclear studies, for example (31)P or (13)C MRS, are often conducted with a single element coil located over the region of interest. (1)H MRS studies have generally employed the same multi-element coils used for MRI, but little consideration has been given as to how the spectroscopic data from the different channels are combined. In many cases it is simply co-added with detrimental effect on the signal to noise ratio. In this study, we derive the optimum method for combining multi-coil data, namely weighting with the ratio of signal to the square of the noise. We show that provided that the noise is uncorrelated, this is the theoretical optimal combination. The method is demonstrated for in vivo proton MRS data acquired using a 32 channel receive coil at 7T in four different brain areas; left motor and right motor, occipital cortex and medial frontal cortex.
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Affiliation(s)
- Emma L Hall
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK.
| | - Mary C Stephenson
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Darren Price
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Peter G Morris
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
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Hall EL, Woolrich MW, Thomaz CE, Morris PG, Brookes MJ. Using variance information in magnetoencephalography measures of functional connectivity. Neuroimage 2012; 67:203-12. [PMID: 23165323 DOI: 10.1016/j.neuroimage.2012.11.011] [Citation(s) in RCA: 37] [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] [Received: 07/31/2012] [Revised: 11/02/2012] [Accepted: 11/09/2012] [Indexed: 10/27/2022] Open
Abstract
The use of magnetoencephalography (MEG) to assess long range functional connectivity across large scale distributed brain networks is gaining popularity. Recent work has shown that electrodynamic networks can be assessed using both seed based correlation or independent component analysis (ICA) applied to MEG data and further that such metrics agree with fMRI studies. To date, techniques for MEG connectivity assessment have typically used a variance normalised approach, either through the use of Pearson correlation coefficients or via variance normalisation of envelope timecourses prior to ICA. Here, we show that the use of variance information (i.e. data that have not been variance normalised) in source space projected Hilbert envelope time series yields important spatial information, and is of significant functional relevance. Further, we show that employing this information in functional connectivity analyses improves the spatial delineation of network nodes using both seed based and ICA approaches. The use of variance is particularly important in MEG since the non-independence of source space voxels (brought about by the ill-posed MEG inverse problem) means that spurious signals can exist in areas of low signal variance. We therefore suggest that this approach be incorporated into future studies.
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Affiliation(s)
- Emma L Hall
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
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Driver ID, Hall EL, Wharton SJ, Pritchard SE, Francis ST, Gowland PA. Calibrated BOLD using direct measurement of changes in venous oxygenation. Neuroimage 2012; 63:1178-87. [PMID: 22971549 PMCID: PMC3485568 DOI: 10.1016/j.neuroimage.2012.08.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 08/02/2012] [Accepted: 08/18/2012] [Indexed: 12/01/2022] Open
Abstract
Calibration of the BOLD signal is potentially of great value in providing a closer measure of the underlying changes in brain function related to neuronal activity than the BOLD signal alone, but current approaches rely on an assumed relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF). This is poorly characterised in humans and does not reflect the predominantly venous nature of BOLD contrast, whilst this relationship may vary across brain regions and depend on the structure of the local vascular bed. This work demonstrates a new approach to BOLD calibration which does not require an assumption about the relationship between cerebral blood volume and cerebral blood flow. This method involves repeating the same stimulus both at normoxia and hyperoxia, using hyperoxic BOLD contrast to estimate the relative changes in venous blood oxygenation and venous CBV. To do this the effect of hyperoxia on venous blood oxygenation has to be calculated, which requires an estimate of basal oxygen extraction fraction, and this can be estimated from the phase as an alternative to using a literature estimate. Additional measurement of the relative change in CBF, combined with the blood oxygenation change can be used to calculate the relative change in CMRO2 due to the stimulus. CMRO2 changes of 18 ± 8% in response to a motor task were measured without requiring the assumption of a CBV/CBF coupling relationship, and are in agreement with previous approaches.
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Affiliation(s)
- Ian D Driver
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom.
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Hall EL, Driver ID, Croal PL, Francis ST, Gowland PA, Morris PG, Brookes MJ. The effect of hypercapnia on resting and stimulus induced MEG signals. Neuroimage 2011; 58:1034-43. [DOI: 10.1016/j.neuroimage.2011.06.073] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 06/01/2011] [Accepted: 06/24/2011] [Indexed: 10/18/2022] Open
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Hale JR, Brookes MJ, Hall EL, Zumer JM, Stevenson CM, Francis ST, Morris PG. Comparison of functional connectivity in default mode and sensorimotor networks at 3 and 7T. MAGMA 2010; 23:339-49. [PMID: 20625794 DOI: 10.1007/s10334-010-0220-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 05/28/2010] [Accepted: 06/18/2010] [Indexed: 11/26/2022]
Abstract
OBJECT The objective of this work was to assess functional connectivity measurements at ultra-high field (7T), given BOLD contrast to noise ratio increases with magnetic field strength but physiological noise also increases. MATERIALS AND METHODS Resting state BOLD data were acquired at 3 and 7T to assess connectivity in the sensorimotor network (SMN) and default mode network (DMN) at different spatial smoothing levels. RESULTS At 3 and 7T positive correlation is observed between a right sensorimotor seed and left sensorimotor cortex. For the DMN, a seed in posterior cingulate cortex results in a high correlation in inferior parietal lobes and medial prefrontal cortex. We show higher temporal correlation coefficients for both the SMN and DMN at 7T compared to 3T for all smoothing levels. A spatial correlation between connectivity maps revealed no significant differences for the SMN, whilst the DMN showed increased spatial correlation dependent on SNR. The maximum physiological noise contribution was found to be higher at 7T, but noise in both seed and network nodes was not significantly increased, as shown by no significant difference in the spatial correlation of maps following physiological correction. CONCLUSION 7T can improve spatial specificity of connectivity maps and facilitate measurement of connectivity in areas of lower intrinsic network correlation.
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Affiliation(s)
- Joanne R Hale
- Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Henning KJ, Hall EL, Dwyer DM, Billmann L, Schuchat A, Johnson JA, Harrison LH. Invasive group B streptococcal disease in Maryland nursing home residents. J Infect Dis 2001; 183:1138-42. [PMID: 11237844 DOI: 10.1086/319278] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [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: 09/12/2000] [Revised: 01/09/2001] [Indexed: 11/03/2022] Open
Abstract
Between 1991 and 1995, among 999 nonpregnant adult Maryland residents with group B Streptococcus (GBS) isolated from a normally sterile site, 84 resided in nursing homes (NHs). The age-adjusted annual incidence of GBS infection (per 100,000 population) among those > or = 65 years old was 72.3 for NH residents and 17.5 for community residents (relative risk, 4.1; P < 0.001). Thirty-four case patients resided in 11 NHs with > or = 2 cases; 1 NH had 8 case patients within 22 months. Six of 8 case patients from 3 NHs had serotype V GBS. Molecular subtyping of several isolates identified 2 case patients in 1 NH with identical subtype patterns. NH residents have a markedly higher incidence of invasive GBS than do community residents > or = 65 years old and may serve as a target group for immunization when GBS vaccines become available. Further evaluation of intra-NH transmission of GBS is warranted.
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Affiliation(s)
- K J Henning
- Epidemiology and Disease Control Program, Maryland Department of Health and Mental Hygiene, Baltimore, MD, USA
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Abstract
Crotaline venoms produce various toxic effects. Although these are most commonly treated with specific antivenoms, surgical management of snakebite has also been practiced for many years. Surgical approaches to pit viper envenomation include incision or excision of the bite site, fasciotomy, and digit dermotomy. The evidence regarding each of these procedures is sparse; however, incision or excision of the bite site are difficult to advocate. Fasciotomy and digit dermotomy may be appropriate in carefully selected patients.
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Affiliation(s)
- E L Hall
- South Georgia Surgical Associates, PC, Thomasville, GA 31799-0520, USA.
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Upreti GC, Hall EL, Koppens D, Oliver JE, Vishwanath R. Studies on the measurement of phospholipase A2 (PLA2) and PLA2 inhibitor activities in ram semen. Anim Reprod Sci 1999; 56:107-21. [PMID: 10463398 DOI: 10.1016/s0378-4320(99)00033-0] [Citation(s) in RCA: 11] [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] [Indexed: 11/17/2022]
Abstract
Extraction with Tris-citrate or Tris-NaCl-EGTA improved the yield of phospholipase A2 (PLA2) from ram semen by 40-50 fold over the previously recommended method of extraction by dilute (0.18 N) sulphuric acid. The enzyme activity in the citrate extract deteriorated more rapidly than in Tris-NaCl-EGTA. The semen PLA2 activity was optimum at pH 8.0, heat sensitive at 70 degrees C for 30 min, activated by Ca2+ (although approximately 60% activity was also found in the absence of calcium) and did not exist as a pro-enzyme. The semen PLA2 activity was equally distributed among the sperm and seminal plasma (SP) components of ram semen. However, the low levels of PLA2 activity in the SP of vasectomised rams tend to suggest that PLA2 in the SP fraction may have originated from testicular or epididymal secretions or leakage, from sperm. PLA, in sperm exists as a large molecular weight aggregate, whereas in SP it is present as a smaller aggregate. In addition to PLA2, semen also contained PLA2 inhibitor activities. Inhibition was observed against PLA2s from bee venom, pig pancreas and oviductal extracts. The inhibitory activity is presumed to be due to a large molecular weight protein as the inhibitor activity was not extracted in a chloroform:methanol (2:1; v/v) mixture, it was non-dialysable, precipitated by 10% trichloroacetic acid and destroyed by proteases. The inhibitor activity was distributed in various molecular weight fractions of sperm, SP and SP from vasectomised rams.
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Affiliation(s)
- G C Upreti
- AgResearch, Dairy and Beef Division, Ruakura Research Centre, Hamilton, New Zealand.
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Smith JC, Stephens DP, Hall EL, Jackson AW, Earnest CP. Effect of oral creatine ingestion on parameters of the work rate-time relationship and time to exhaustion in high-intensity cycling. Eur J Appl Physiol Occup Physiol 1998; 77:360-5. [PMID: 9562365 DOI: 10.1007/s004210050345] [Citation(s) in RCA: 53] [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] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The relationship between work rate (W) and time to exhaustion (t) during intense exercise is commonly described by either a hyperbolic function (NLin), t= W'/(W-Wcp), or by its linear equivalent (LinW) Wlim=W' + Wcp(t). The parameter Wcp (critical power) has been described as an inherent characteristic of the aerobic energy system, while W' has been shown to be a ralid estimate of anaerobic work capacity. Recent studies have demonstrated that oral supplementation of creatine monohydrate (CrH2O) increases total muscle creatine stores, and have linked these increases to improved performances in intense intermittent exercise. This study was conducted to determine the effect of CrH2O supplementation on estimates of W' and Wcp derived from the NLin and LinW equations, and to determine the effect of CrH2O on t in exhaustive constant power exercise of different intensities. Fifteen active but untrained university students completed three phases of testing on a cycle ergometer: (1) familiarization, three learning trials, (2) baseline determination of W' and Wcp, four bouts performed at a W selected to elicit fatigue in 90-600 s, and (3) experimental determination of W' and Wcp, four bouts performed at the same W as baseline, but performed after 5 days of ingesting either a placebo (4 x 6 g of glucose/day) or CrH2O (4 x 5 g of CrH2O and 1 g glucose/day). Testing was administered in a double-blind manner. Analyses of covariance revealed a significant effect for CrH2O on both estimates of W' (NLin, P=0.04; LinW, P < 0.01), but not on estimates of Wcp (NLin, P=0.37; LinW; P=0.30). Within groups, t was significantly different for only CrH2O at the two highest Ws (P=0.04). It is concluded that oral ingestion of CrH2O increases estimates of W' due to an improved t at the shorter, more intense exercise bouts.
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Affiliation(s)
- J C Smith
- Southwestern University, Department of Kinesiology, Georgetown, TX 78627, USA
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Abstract
STUDY OBJECTIVE To document the clinical presentation and course of consecutive cases of envenomation by the canebrake rattlesnake (Crotalus horridus atricaudatus). METHODS The medical care provided all patients envenomated by canebrake rattlesnakes in two institutions was retrospectively reviewed. Particular attention was paid to coagulation abnormalities, serum enzymes, electrocardiographic findings, and treatment with antivenom. RESULTS Of the 15 patients, envenomation was judged to be mild in 3, moderate in 6, and severe in 5. In one case envenomation caused death. The clinical course generally predicted the degree of increase in the serum creatinine kinase (CK) level, as well as the amount of antivenom used for treatment. Despite increases in serum CK concentration and frequent increases in the serum CK-MB fraction, we found no evidence of cardiac damage. CONCLUSION In envenomation by North American pit vipers, rhabdomyolysis appears to be characteristic of envenomation by the canebrake rattlesnake. We speculate that toxins in the canebrake venom cause skeletal muscle rhabdomyolysis. Physicians caring for victims of canebrake bite should regard marked increases in CK concentration as coming from skeletal, not cardiac, muscle. Good general medical support and antivenom for victims with moderate to severe envenomation appears effective.
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Affiliation(s)
- R R Carroll
- Department of Medicine, University of Florida, Gainesville, USA
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Affiliation(s)
- G A Holt
- School of Pharmacy, Samford University, Birmingham, Ala
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Affiliation(s)
- G A Holt
- Samford University, Birmingham, AL
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Hall EL, Andrews R. Mechanics of cardiopulmonary resuscitation: past, present, future. J Med Assoc Ga 1985; 74:842-4. [PMID: 4093731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Holt GA, Hall EL. Is administrative immunity a destructive shield in your department? Curr Concepts Hosp Pharm Manage 1985; 6:7-9. [PMID: 10264575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Hall EL, Davies DL, Casey ME. The selection of critical subsets for signal, image, and scene matching. IEEE Trans Pattern Anal Mach Intell 1980; 2:313-322. [PMID: 21868907 DOI: 10.1109/tpami.1980.4767030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [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
A basic matching problem consists of locating a reference subset in a larger set of data subject to a given criterion. Variations of the problem include template matching for object recognition, matched filtering for signal detection, image registration, change detection, cartography feature location, correlation guidance, and scene matching. In the general case the data sets may be made by completely different sensors at different geometrical orientations. A data set in N dimensions can be considered as a function in N-space. The critical subset selection problem arises when one is given a function and must select some subset of the function to match with the original. In some cases uniqueness is a key feature of the best subset. Uniqueness may be measured by the number and relative magnitudes of the peaks in the cross correlation function of the original and subset functions. For a unique subset, another desirable characteristic is lack of ambiguity. This characteristic may be measured using the correlation length or 50 percent width of the main correlation peak. The smaller the correlation length, the greater the certainty one has in detecting the correct match position. In this paper a method is presented for selecting the ``best'' subset of a scene where best is defined in terms of the minimum correlation length. The best solution is shown to be a function of the entire scene, i.e., an improper subset.
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Affiliation(s)
- E L Hall
- SENIOR MEMBER, IEEE, Department of Electrical Engineering, University of Tennessee, Knoxville, TN 37916
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Abstract
Recognition of three-dimensional objects independent of size, position, and orientation is an important and difficult problem of scene analysis. The use of three-dimensional moment invariants is proposed as a solution. The generalization of the results of two-dimensional moment invariants which had linked two-dimensional moments to binary quantics is done by linking three-dimensional moments to ternary quantics. The existence and number of nth order moments in two and three dimensions is explored. Algebraic invariants of several ternary forms under different orthogonal transformations are derived by using the invariant property of coefficients of ternary forms. The result is a set of three-dimensional moment invariants which are invariant under size, orientation, and position change. This property is highly significant in compressing the data which are needed in three-dimensional object recognition. Empirical examples are also given.
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Affiliation(s)
- F A Sadjadi
- STUDENT MEMBER, IEEE, Department of Electrical Engineering, University of Tennessee, Knoxville, TN 37916
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Abstract
The problem of matching two images of the same scene, taken by different sensors under different viewing geometries, is a challenging problem in the field of image processing and pattern recognition. The scenes are usually transformed so drastically by the different viewing geometries and sensor characteristics that it is extremely difficult, if not impossible, to match the original images without the proper data processing. Geometric and intensity transformations must be performed to bring the matching elements and their intensity into a one-to-one correspondence. Objects of interest represented by subimages of one scene were located in the other using scene matching techniques with intensity difference and edge features as measurement features. Performance characteristics of the matches by these techniques are presented in terms of the probability of a match as a function of the probability of false fix.
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Affiliation(s)
- R Y Wong
- Department of Electrical Engineering, California State University, Northridge, CA 91330
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Abstract
A hybrid optical-digital system for automated measurement and disease classification of chest radiographs has been constructed. Initial results from the use of this system for classification of opacity textural patterns associated with a specific diffuse lung disease (coal workers pneumoconiosis) are presented. This system consists of three subsystems which include a digital image scanner for lung field detection, a computercontrolled X - Y transport for film positioning, and a Fraunhofer diffraction pattern sampling unit for opacity detection and measurement. A minicomputer is used to integrate these subsystems as well as render a film quality and disease classification through the use of discriminant functions and probability estimates.
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Hall EL, Mueller BS. Effect of training on the mental illness ideologies of nursing assistants. Nurs Res 1968; 17:172-4. [PMID: 5183584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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