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Alghanimy A, Work LM, Holmes WM. The glymphatic system and multiple sclerosis: An evolving connection. Mult Scler Relat Disord 2024; 83:105456. [PMID: 38266608 DOI: 10.1016/j.msard.2024.105456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 01/18/2024] [Indexed: 01/26/2024]
Abstract
Multiple sclerosis (MS) is a complex autoimmune disorder that affects the central nervous system, resulting in demyelination and an array of neurological manifestations. Recently, there has been significant scientific interest in the glymphatic system, which operates as a waste-clearance system for the brain. This article reviews the existing literature, and explores potential links between the glymphatic system and MS, shedding light on its evolving significance in the context of MS pathogenesis. The authors consider the pathophysiological implications of glymphatic dysfunction in MS, the impact of disrupted sleep on glymphatic function, and the bidirectional relationship between MS and sleep disturbances. By offering an understanding of the intricate interplay between the glymphatic system and MS, this review provides valuable insights which may lead to improved diagnostic techniques and more effective therapeutic interventions.
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Affiliation(s)
- Alaa Alghanimy
- School of Psychology and Neuroscience, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow G61 1QH, United Kingdom; Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
| | - Lorraine M Work
- School of Cardiovascular and Metabolic Health, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow G12 8TA, United Kingdom
| | - William M Holmes
- School of Psychology and Neuroscience, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow G61 1QH, United Kingdom
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Lopez Gonzalez R, Holmes WM. Editorial for "Reference Values for Fetal Cardiac Dimensions, Volumes, Ventricular Function and Left Ventricular Longitudinal Strain Using Doppler Ultrasound Gated Cardiac Magnetic Resonance Imaging in Healthy Third Trimester Fetuses". J Magn Reson Imaging 2023. [PMID: 37855664 DOI: 10.1002/jmri.29075] [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: 09/20/2023] [Revised: 09/22/2023] [Accepted: 09/22/2023] [Indexed: 10/20/2023] Open
Affiliation(s)
- Rosario Lopez Gonzalez
- Department of Clinical Physics and Bioengineering, National Health Service Greater Glasgow and Clyde, Glasgow, UK
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - William M Holmes
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Paterson S, Vallatos A, Rodgers J, Holmes WM. Application of diffusion weighted multiple boli ASL to a murine model of human African trypanosomiasis. Sci Rep 2023; 13:8684. [PMID: 37248398 DOI: 10.1038/s41598-023-34665-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/05/2023] [Indexed: 05/31/2023] Open
Abstract
Human African Trypanosomiasis (HAT) is a parasitic disease originating in sub-Saharan Africa. There is limited information about the changes in the blood brain barrier (BBB) during this infection. This study is the first to apply diffusion weighted ASL (DWASL) to examine changes in BBB impairment. No significant changes in water exchange across the BBB were found during the infection, even when a loss of barrier integrity was seen using Contrast Enhanced MRI (Gd-DTPA) during the late stage of the disease. Furthermore, using multiple boli ASL (mbASL), changes in cerebral blood flow (CBF) were found during the course of infection. Overall, this study highlights the need for further study of the BBB during HAT infection to understand the complex mechanisms behind impairment.
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Affiliation(s)
- Samantha Paterson
- Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Jean Rodgers
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK.
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Alghanimy A, Martin C, Gallagher L, Holmes WM. The effect of a novel AQP4 facilitator, TGN-073, on glymphatic transport captured by diffusion MRI and DCE-MRI. PLoS One 2023; 18:e0282955. [PMID: 36920936 PMCID: PMC10016657 DOI: 10.1371/journal.pone.0282955] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
The glymphatic system is a low resistance pathway, by which cerebrospinal fluid enters the brain parenchyma along perivascular spaces via AQP4 channels. It is hypothesised that the resulting convective flow of the interstitial fluid provides an efficient mechanism for the removal of waste toxins from the brain. Therefore, enhancing AQP4 function might protect against neurodegenerative diseases such as Alzheimer's disease (AD), in which the accumulation of harmful proteins and solutes is a hallmark feature. Here, we test the effect of a putative AQP4 facilitator, TGN-073, on glymphatic transport in a normal rat brain by employing different MRI techniques. Surgical procedures were undertaken to catheterise the cisterna magna, thereby enabling infusion of the MRI tracer. Followed by the intraperitoneal injection of either TGN-073, or the vehicle. Using a paramagnetic contrast agent (Gd-DTPA) as the MRI tracer, dynamic 3D T1 weighted imaging of the glymphatic system was undertaken over two hours. Further, the apparent diffusion coefficient was measured in different brain regions using diffusion-weighted imaging (DWI). While physiological parameters and arterial blood gas analysis were monitored continuously. We found that rats treated with TGN-073 showed the distribution of Gd-DTPA was more extensive and parenchymal uptake was higher compared with the vehicle group. Water diffusivity was increased in the brain of TGN-073 treated group, which indicates greater water flux. Also, MRI showed the glymphatic transport and distribution in the brain is naturally heterogeneous, which is consistent with previous studies. Our results indicate that compounds such as TGN-073 can improve glymphatic function in the brain. Since glymphatic impairment due to AQP4 dysfunction is potentially associated with several neurological disorders such as AD, dementia and traumatic brain injury, enhancing AQP4 functionality might be a promising therapeutic target.
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Affiliation(s)
- Alaa Alghanimy
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Conor Martin
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Lindsay Gallagher
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - William M. Holmes
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
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Al-Mubarak H, Vallatos A, Gallagher L, Birch J, Chalmers AJ, Holmes WM. Evaluating potential of multi-parametric MRI using co-registered histology: Application to a mouse model of glioblastoma. Magn Reson Imaging 2021; 85:121-127. [PMID: 34687852 DOI: 10.1016/j.mri.2021.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 04/23/2021] [Accepted: 10/17/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Conventional MRI fails to detect regions of glioblastoma cell infiltration beyond the contrast-enhanced T1 solid tumor region, with infiltrating tumor cells often migrating along host blood vessels. PURPOSE MRI is capable of generating a range of image contrasts which are commonly assessed individually by qualitative visual inspection. It has long been hypothesized that better diagnoses could be achieved by combining these multiple images, so called multi-parametric or multi-spectral MRI. However, the lack of clinical histology and the difficulties of co-registration, has meant this hypothesis has never been rigorously tested. Here we test this hypothesis, using a previously published multi-dimensional dataset consisting of registered MR images and histology. STUDY TYPE Animal Model. SUBJECTS Mice bearing orthotopic glioblastoma xenografts generated from a patient-derived glioblastoma cell line. FIELD STRENGTH/SEQUENCES 7 Tesla, T1/T2 weighted, T2 mapping, contrast enhance T1, diffusion-weighted, diffusion tensor imaging. ASSESSMENT Immunohistochemistry sections were stained for Human Leukocyte Antigen (probing human-derived tumor cells). To achieve quantitative MRI-tissue comparison, multiple histological slices cut in the MRI plane were stacked to produce tumor cell density maps acting as 'ground truth'. STATISTICAL TESTS Sensitivity, specificity, accuracy and Dice similarity indices were calculated. ANOVA, t-test, Bonferroni correction and Pearson coefficients were used for statistical analysis. RESULTS Correlation coefficient analysis with co-registered 'ground truth' histology showed interactive regression maps had higher correlation coefficients and sensitivity values than T2W, ADC, FA, and T2map. Further, the interaction regression maps showed statistical improved detection of tumor volume. DATA CONCLUSION Voxel-by-voxel analysis provided quantitative evidence confirming the hypothesis that mpMRI can, potentially, better distinguish between the tumor region and normal tissue.
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Affiliation(s)
- H Al-Mubarak
- Glasgow Experimental MRI centre, Institute of Neuroscience and Psychology, University of Glasgow, G61 1QH, UK; Department of Physics, College of Science, University of Misan, Iraq.
| | - A Vallatos
- Centre for Clinical Brain Sciences, University of Edinburgh, EH16 4SB,UK.
| | - L Gallagher
- Glasgow Experimental MRI centre, Institute of Neuroscience and Psychology, University of Glasgow, G61 1QH, UK.
| | - J Birch
- Beatson Institute for Cancer Research, UK.
| | - A J Chalmers
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences University of Glasgow, G61 1QH, UK.
| | - W M Holmes
- Glasgow Experimental MRI centre, Institute of Neuroscience and Psychology, University of Glasgow, G61 1QH, UK.
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Abstract
The recently proposed glymphatic pathway for solute transport and waste clearance from the brain has been the focus of intense debate. By exploiting an isotopically enriched MRI tracer, H217O, we directly imaged glymphatic water transport in the rat brain in vivo. Our results reveal glymphatic transport that is dramatically faster and more extensive than previously thought and unlikely to be explained by diffusion alone. Moreover, we confirm the critical role of aquaporin-4 channels in glymphatic transport.
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Affiliation(s)
- Mohammed S Alshuhri
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom.,Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al Kharj, Saudi Arabia
| | - Lindsay Gallagher
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Lorraine M Work
- Institute of Cardiovascular and Medical Sciences, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - William M Holmes
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
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7
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Al-Mubarak HFI, Vallatos A, Holmes WM. Impact of turbulence-induced asymmetric propagators on the accuracy of phase-contrast velocimetry. J Magn Reson 2021; 325:106929. [PMID: 33713991 DOI: 10.1016/j.jmr.2021.106929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/14/2021] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
Phase-contrast magnetic resonance velocimetry (PC-MRI) has been widely used to investigate flow properties in numerous systems. In a horizontal cylindrical pipe (3 mm diameter), we investigated the accuracy of PC-MRI as the flow transitioned from laminar to turbulent flow (Reynolds number 352-2708). We focus primarily on velocimetry errors introduced by skewed intra-voxel displacement distributions, a consequence of PC-MRI theory assuming symmetric distributions. We demonstrated how rapid fluctuations in the velocity field, can produce broad asymmetric intravoxel displacement distributions near the wall. Depending on the shape of the distribution, this resulted in PC-MRI measurements under-estimating (positive skewness) or over-estimating (negative skewness) the true mean intravoxel velocity, which could have particular importance to clinical wall shear stress measurements. The magnitude of these velocity errors was shown to increase with the variance and decrease with the kurtosis of the intravoxel displacement distribution. These experimental results confirm our previous theoretical analysis, which gives a relationship for PC-MRI velocimetry errors, as a function of the higher moments of the intravoxel displacement distribution (skewness, variance, and kurtosis) and the experimental parameters q and Δ. This suggests that PC-MRI errors in such unsteady/turbulent flow conditions can potentially be reduced by employing lower q values or shorter observation times Δ.
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Affiliation(s)
- Haitham F I Al-Mubarak
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK; Department of Physics, College of Science, Misan University, Iraq
| | - Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK; Centre for Clinical Brain Sciences, University of Edinburgh, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.
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Jayasekera G, Wilson KS, Buist H, Woodward R, Uckan A, Hughes C, Nilsen M, Church AC, Johnson MK, Gallagher L, Mullin J, MacLean MR, Holmes WM, Peacock AJ, Welsh DJ. Understanding longitudinal biventricular structural and functional changes in a pulmonary hypertension Sugen-hypoxia rat model by cardiac magnetic resonance imaging. Pulm Circ 2020; 10:2045894019897513. [PMID: 32095230 PMCID: PMC7011361 DOI: 10.1177/2045894019897513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 12/05/2019] [Indexed: 01/24/2023] Open
Abstract
Cardiac magnetic resonance-derived ventricular variables are predictive of mortality in pulmonary arterial hypertension. Rodent models which emphasize ventricular function, allowing serial monitoring, are needed to identify pathophysiological features and novel therapies for pulmonary arterial hypertension. We investigated longitudinal changes in the Sugen–hypoxia model during disease progression. Sprague Dawley rats (n = 32) were divided into two groups. (1) Sugen–hypoxia: a dose of subcutaneous Sugen-5416 and placed in hypobaric hypoxia for two weeks followed by normoxia for three weeks. (2) Normoxia: maintained at normal pressure for five weeks. Rats were examined at five or eight weeks with right-heart catheter, cardiac magnetic resonance, and autopsy. Compared to normoxic controls (23.9 ± 4.1 mmHg), right ventricular systolic pressure was elevated in Sugen–hypoxia rats at five and eight weeks (40.9 ± 15.5 mmHg, p = 0.026; 48.9 ± 9.6 mmHg, p = 0.002). Right ventricular end-systolic volume index was increased in eight weeks Sugen–hypoxia (0.28 ± 0.04 µlcm–2, p = 0.003) compared to normoxic controls (0.18 ±0.03 mlcm–2). There was progressive dilatation of the right ventricular at eight weeks Sugen–hypoxia compared to normoxic controls (0.75 ± 0.13 µlcm–2 vs 0.56 ± 0.1 µlcm–2p = 0.02). Ventricle mass index by cardiac magnetic resonance at five weeks (0.34 ± 0.06, p = 0.003) and eight weeks Sugen–hypoxia (0.34 ± 0.06, p = 0.002) were higher than normoxic controls (0.21 ± 0.04). Stroke volume, right ventricular ejection fraction, and left ventricular variables were preserved in Sugen–hypoxia. Ventricular changes during the course of illness in a pulmonary arterial hypertension rodent model can be examined by cardiac magnetic resonance. These changes including right ventricular hypertrophy and subsequent dilatation are similar to those seen in pulmonary arterial hypertension patients. Despite the persisting pulmonary hypertension, there are features of adaptive cardiac remodeling through the study duration.
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Affiliation(s)
| | - Kathryn S Wilson
- Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK
| | - Hanna Buist
- Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK
| | | | | | | | | | - A Colin Church
- Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK
| | - Martin K Johnson
- Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK
| | | | | | | | | | - Andrew J Peacock
- Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK
| | - David J Welsh
- Scottish Pulmonary Vascular Unit, Glasgow Caledonian University, Glasgow, UK
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Al-Mubarak H, Vallatos A, Gallagher L, Birch JL, Gilmour L, Foster JE, Chalmers AJ, Holmes WM. Stacked in-plane histology for quantitative validation of non-invasive imaging biomarkers: Application to an infiltrative brain tumour model. J Neurosci Methods 2019; 326:108372. [PMID: 31348965 DOI: 10.1016/j.jneumeth.2019.108372] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 07/20/2019] [Accepted: 07/21/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND While it is generally agreed that histopathology is the gold standard for assessing non-invasive imaging biomarkers, most validation has been by qualitative visual comparison. To date, the difficulties involved in accurately co-registering histology sections with imaging slices have prevented a voxel-by-voxel assessment of imaging modalities. By contrast with previous studies, which focus on improving the registration algorithms, we have taken the approach of improving the quality of the histological processing and analysis. NEW METHOD To account for imaging slice orientation and thickness, multiple histology sections were cut in the MR imaging plane and averaged to produce stacked in-plane histology (SIH) maps. When combined with intensity sensitive staining this approach gives histopathology maps, which can be used as the gold standard to validate imaging biomarkers. RESULTS We applied this pipeline to a patient-derived mouse model of glioblastoma multiforme (GBM). Increasing the number of stacked histology sections significantly increased SIH measured tumour volume. The SIH technique proposed here resulted in reduced variability of volume measurements and this allowed significant improvements in the quantitative volumetric assessment of multiple MRI modalities. Further, high quality registration enabled a voxel-wise comparison between MRI and histopathology maps. Previous approaches to the validation of imaging biomarkers with histology, have been either qualitative or of limited accuracy. Here we propose a pipeline that allows for a more accurate validation via co-registration with SIH maps, potentially allowing validation in a voxel-wise mode. CONCLUSION This work demonstrates that methodically produced SIH maps facilitate the quantitative histopathologic assessment of imaging biomarkers.
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Affiliation(s)
- H Al-Mubarak
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, G61 1QH, UK; Department of Physics, College of Science, University of Misan, Iraq.
| | - A Vallatos
- Centre for Clinical Brain Sciences, University of Edinburgh, EH16 4SB, UK.
| | - L Gallagher
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, G61 1QH, UK.
| | - J L Birch
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences University of Glasgow, G61 1QH, UK.
| | - L Gilmour
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences University of Glasgow, G61 1QH, UK.
| | - J E Foster
- Department of Clinical Physics and Bioengineering, Greater Glasgow Health Board and University of Glasgow, B15 2GW, UK.
| | - A J Chalmers
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences University of Glasgow, G61 1QH, UK.
| | - W M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, G61 1QH, UK.
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Jones FE, Murray LS, McNeilly S, Dean A, Aman A, Lu Y, Nikolova N, Malomgré R, Horsburgh K, Holmes WM, Kadler KE, Van Agtmael T. 4-Sodium phenyl butyric acid has both efficacy and counter-indicative effects in the treatment of Col4a1 disease. Hum Mol Genet 2019; 28:628-638. [PMID: 30351356 PMCID: PMC6360271 DOI: 10.1093/hmg/ddy369] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/11/2018] [Indexed: 12/22/2022] Open
Abstract
Mutations in the collagen genes COL4A1 and COL4A2 cause Mendelian eye, kidney and cerebrovascular disease including intracerebral haemorrhage (ICH), and common collagen IV variants are a risk factor for sporadic ICH. COL4A1 and COL4A2 mutations cause endoplasmic reticulum (ER) stress and basement membrane (BM) defects, and recent data suggest an association of ER stress with ICH due to a COL4A2 mutation. However, the potential of ER stress as a therapeutic target for the multi-systemic COL4A1 pathologies remains unclear. We performed a preventative oral treatment of Col4a1 mutant mice with the chemical chaperone phenyl butyric acid (PBA), which reduced adult ICH. Importantly, treatment of adult mice with the established disease also reduced ICH. However, PBA treatment did not alter eye and kidney defects, establishing tissue-specific outcomes of targeting Col4a1-derived ER stress, and therefore this treatment may not be applicable for patients with eye and renal disease. While PBA treatment reduced ER stress and increased collagen IV incorporation into BMs, the persistence of defects in BM structure and reduced ability of the BM to withstand mechanical stress indicate that PBA may be counter-indicative for pathologies caused by matrix defects. These data establish that treatment for COL4A1 disease requires a multipronged treatment approach that restores both ER homeostasis and matrix defects. Alleviating ER stress is a valid therapeutic target for preventing and treating established adult ICH, but collagen IV patients will require stratification based on their clinical presentation and mechanism of their mutations.
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Affiliation(s)
- Frances E Jones
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Lydia S Murray
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah McNeilly
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Afshan Dean
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Alisha Aman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Yinhui Lu
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Nija Nikolova
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Ruben Malomgré
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Karen Horsburgh
- Centre for Discovery Brain Sciences, Medical School, University of Edinburgh, Edinburgh, UK
| | - William M Holmes
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Karl E Kadler
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Tom Van Agtmael
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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11
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Vallatos A, Al-Mubarak HFI, Birch JL, Galllagher L, Mullin JM, Gilmour L, Holmes WM, Chalmers AJ. Quantitative histopathologic assessment of perfusion MRI as a marker of glioblastoma cell infiltration in and beyond the peritumoral edema region. J Magn Reson Imaging 2018; 50:529-540. [PMID: 30569620 DOI: 10.1002/jmri.26580] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/26/2018] [Accepted: 10/26/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Conventional MRI fails to detect regions of glioblastoma cell infiltration beyond the contrast-enhanced T1 solid tumor region, with infiltrating tumor cells often migrating along host blood vessels. PURPOSE To quantitatively and qualitatively analyze the correlation between perfusion MRI signal and tumor cell density in order to assess whether local perfusion perturbation could provide a useful biomarker of glioblastoma cell infiltration. STUDY TYPE Animal model. SUBJECTS Mice bearing orthotopic glioblastoma xenografts generated from a patient-derived glioblastoma cell line. FIELD STRENGTH/SEQUENCES 7T perfusion images acquired using a high signal-to-noise ratio (SNR) multiple boli arterial spin labeling sequence were compared with conventional MRI (T1 /T2 weighted, contrast-enhanced T1 , diffusion-weighted, and apparent diffusion coefficient). ASSESSMENT Immunohistochemistry sections were stained for human leukocyte antigen (probing human-derived tumor cells). To achieve quantitative MRI-tissue comparison, multiple histological slices cut in the MRI plane were stacked to produce tumor cell density maps acting as a "ground truth." STATISTICAL TESTS Sensitivity, specificity, accuracy, and Dice similarity indices were calculated and a two-tailed, paired t-test used for statistical analysis. RESULTS High comparison test results (Dice 0.62-0.72, Accuracy 0.86-0.88, Sensitivity 0.51-0.7, and Specificity 0.92-0.97) indicate a good segmentation for all imaging modalities and highlight the quality of the MRI tissue assessment protocol. Perfusion imaging exhibits higher sensitivity (0.7) than conventional MRI (0.51-0.61). MRI/histology voxel-to-voxel comparison revealed a negative correlation between tumor cell infiltration and perfusion at the tumor margins (P = 0.0004). DATA CONCLUSION These results demonstrate the ability of perfusion imaging to probe regions of low tumor cell infiltration while confirming the sensitivity limitations of conventional imaging modalities. The quantitative relationship between tumor cell density and perfusion identified in and beyond the edematous T2 hyperintensity region surrounding macroscopic tumor could be used to detect marginal tumor cell infiltration with greater accuracy. LEVEL OF EVIDENCE 1 Technical stage: 2 J. Magn. Reson. Imaging 2019;50:529-540.
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Affiliation(s)
- A Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, UK
| | - H F I Al-Mubarak
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.,University of Misan, Iraq
| | - J L Birch
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, UK
| | - L Galllagher
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - J M Mullin
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - L Gilmour
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, UK
| | - W M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - A J Chalmers
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, UK
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Birch JL, Strathdee K, Gilmour L, Vallatos A, McDonald L, Kouzeli A, Vasan R, Qaisi AH, Croft DR, Crighton D, Gill K, Gray CH, Konczal J, Mezna M, McArthur D, Schüttelkopf AW, McConnell P, Sime M, Holmes WM, Bower J, McKinnon HJ, Drysdale M, Olson MF, Chalmers AJ. A Novel Small-Molecule Inhibitor of MRCK Prevents Radiation-Driven Invasion in Glioblastoma. Cancer Res 2018; 78:6509-6522. [PMID: 30279244 DOI: 10.1158/0008-5472.can-18-1697] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 06/08/2018] [Revised: 08/10/2018] [Accepted: 09/17/2018] [Indexed: 11/16/2022]
Abstract
Glioblastoma (GBM) is an aggressive and incurable primary brain tumor that causes severe neurologic, cognitive, and psychologic symptoms. Symptoms are caused and exacerbated by the infiltrative properties of GBM cells, which enable them to pervade the healthy brain and disrupt normal function. Recent research has indicated that although radiotherapy (RT) remains the most effective component of multimodality therapy for patients with GBM, it can provoke a more infiltrative phenotype in GBM cells that survive treatment. Here, we demonstrate an essential role of the actin-myosin regulatory kinase myotonic dystrophy kinase-related CDC42-binding kinase (MRCK) in mediating the proinvasive effects of radiation. MRCK-mediated invasion occurred via downstream signaling to effector molecules MYPT1 and MLC2. MRCK was activated by clinically relevant doses per fraction of radiation, and this activation was concomitant with an increase in GBM cell motility and invasion. Furthermore, ablation of MRCK activity either by RNAi or by inhibition with the novel small-molecule inhibitor BDP-9066 prevented radiation-driven increases in motility both in vitro and in a clinically relevant orthotopic xenograft model of GBM. Crucially, treatment with BDP-9066 in combination with RT significantly increased survival in this model and markedly reduced infiltration of the contralateral cerebral hemisphere.Significance: An effective new strategy for the treatment of glioblastoma uses a novel, anti-invasive chemotherapeutic to prevent infiltration of the normal brain by glioblastoma cells.Cancer Res; 78(22); 6509-22. ©2018 AACR.
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Affiliation(s)
- Joanna L Birch
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom.
| | - Karen Strathdee
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Lesley Gilmour
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Antoine Vallatos
- Glasgow Experimental MRI Centre, University of Glasgow, Glasgow, United Kingdom
| | - Laura McDonald
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Ariadni Kouzeli
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Richa Vasan
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - Daniel R Croft
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Diane Crighton
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Kathryn Gill
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Christopher H Gray
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Jennifer Konczal
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Mokdad Mezna
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Duncan McArthur
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Alexander W Schüttelkopf
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Patricia McConnell
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Mairi Sime
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - William M Holmes
- Glasgow Experimental MRI Centre, University of Glasgow, Glasgow, United Kingdom
| | - Justin Bower
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Heather J McKinnon
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Martin Drysdale
- CRUK Beatson Drug Discovery Programme, Beatson Institute of Cancer Research, Glasgow, United Kingdom
| | - Michael F Olson
- CRUK Beatson Institute of Cancer Research, Glasgow, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anthony J Chalmers
- Wolfson Wohl Translational Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
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Vallatos A, Al-Mubarak HFI, Mullin JM, Holmes WM. Accuracy of phase-contrast velocimetry in systems with skewed intravoxel velocity distributions. J Magn Reson 2018; 296:121-129. [PMID: 30245475 DOI: 10.1016/j.jmr.2018.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Phase contrast velocimetry (PCV) has been widely used to investigate flow properties in numerous systems. Several authors have reported errors in velocity measurements and have speculated on the sources, which have ranged from eddy current effects to acceleration artefacts. An often overlooked assumption in the theory of PCV, which may not be met in complex or unsteady flows, is that the intravoxel displacement distributions (propagators) are symmetric. Here, the effect of the higher moments of the displacement distribution (variance, skewness and kurtosis) on the accuracy of PCV is investigated experimentally and theoretically. Phase and propagator measurements are performed on tailored intravoxel distributions, achieved using a simple phantom combined with a single large voxel. Asymmetric distributions (Skewness ≠ 0) are shown to generate important phase measurement errors that lead to significant velocimetry errors. Simulations of the phase of the spin vector sum, based on experimentally measured propagators, are shown to quantitatively reproduce the relationship between measured phase and experimental parameters. These allow relating the observed velocimetry errors to a discrepancy between the average phase of intravoxel spins considered in PCV theory and the vector phase actually measured by a PFG experiment. A theoretical expression is derived for PCV velocimetry errors as a function of the moments of the displacement distribution. Positively skewed distributions result in an underestimation of the true mean velocity, while negatively skewed distributions result in an overestimation. The magnitude of these errors is shown to increase with the variance and decrease with the kurtosis of the intravoxel displacement distribution.
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Affiliation(s)
- Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK; Centre for Clinical Brain Sciences, University of Edinburgh, UK
| | - Haitham F I Al-Mubarak
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - James M Mullin
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.
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Thow LA, MacDonald K, Holmes WM, Muir KW, Macrae IM, Dewar D. Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats. Brain Neurosci Adv 2018; 2:2398212818794820. [PMID: 32166145 PMCID: PMC7058243 DOI: 10.1177/2398212818794820] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
Background: Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit. Methods: Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T2-weighted magnetic resonance imaging. Results: Glucose administration had no effect on the severity of ischaemia when assessed by either 99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient–derived lesion volume 2–4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group. Conclusions: Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear.
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Affiliation(s)
- Lisa A Thow
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Kathleen MacDonald
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - William M Holmes
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Keith W Muir
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Deborah Dewar
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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Deuchar GA, Brennan D, Holmes WM, Shaw M, Macrae IM, Santosh C. Perfluorocarbon Enhanced Glasgow Oxygen Level Dependent (GOLD) Magnetic Resonance Metabolic Imaging Identifies the Penumbra Following Acute Ischemic Stroke. Am J Cancer Res 2018; 8:1706-1722. [PMID: 29556351 PMCID: PMC5858177 DOI: 10.7150/thno.21685] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 12/16/2017] [Indexed: 01/27/2023] Open
Abstract
The ability to identify metabolically active and potentially salvageable ischaemic penumbra is crucial for improving treatment decisions in acute stroke patients. Our solution involves two complementary novel MRI techniques (Glasgow Oxygen Level Dependant (GOLD) Metabolic Imaging), which when combined with a perfluorocarbon (PFC) based oxygen carrier and hyperoxia can identify penumbra due to dynamic changes related to continued metabolism within this tissue compartment. Our aims were (i) to investigate whether PFC offers similar enhancement of the second technique (Lactate Change) as previously demonstrated for the T2*OC technique (ii) to demonstrate both GOLD metabolic imaging techniques working concurrently to identify penumbra, following administration of Oxycyte® (O-PFC) with hyperoxia. Methods: An established rat stroke model was utilised. Part-1: Following either saline or PFC, magnetic resonance spectroscopy was applied to investigate the effect of hyperoxia on lactate change in presumed penumbra. Part-2; rats received O-PFC prior to T2*OC (technique 1) and MR spectroscopic imaging, which was used to identify regions of tissue lactate change (technique 2) in response to hyperoxia. In order to validate the techniques, imaging was followed by [14C]2-deoxyglucose autoradiography to correlate tissue metabolic status to areas identified as penumbra. Results: Part-1: PFC+hyperoxia resulted in an enhanced reduction of lactate in the penumbra when compared to saline+hyperoxia. Part-2: Regions of brain tissue identified as potential penumbra by both GOLD metabolic imaging techniques utilising O-PFC, demonstrated maintained glucose metabolism as compared to adjacent core tissue. Conclusion: For the first time in vivo, enhancement of both GOLD metabolic imaging techniques has been demonstrated following intravenous O-PFC+hyperoxia to identify ischaemic penumbra. We have also presented preliminary evidence of the potential therapeutic benefit offered by O-PFC. These unique theranostic applications would enable treatment based on metabolic status of the brain tissue, independent of time from stroke onset, leading to increased uptake and safer use of currently available treatment options.
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Faller KME, Leach J, Johnston P, Holmes WM, Macrae IM, Frenguelli BG. Proof of concept and feasibility studies examining the influence of combination ribose, adenine and allopurinol treatment on stroke outcome in the rat. Brain Neurosci Adv 2017; 1:2398212817717112. [PMID: 32166133 PMCID: PMC7058219 DOI: 10.1177/2398212817717112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/31/2017] [Indexed: 01/21/2023] Open
Abstract
Background Cerebral ischaemia results in a rapid and profound depletion of adenosine triphosphate (ATP), the energy currency of the cell. This depletion leads to disruption of cellular homeostasis and cell death. Early replenishment of ATP levels might therefore have a neuroprotective effect in the injured brain. We have previously shown that the ATP precursors, D-ribose and adenine (RibAde), restored the reduced ATP levels in rat brain slices to values similar to those measured in the intact rodent brain. The aim of this study was to assess whether RibAde, either alone or in combination with the xanthine oxidase inhibitor allopurinol (RibAdeAll; to further increase the availability of ATP precursors), could improve outcome in an in vivo rodent model of transient cerebral ischaemia. Methods After 60 min occlusion of the middle cerebral artery, and upon reperfusion, rats were administered saline, RibAde, or RibAdeAll for 6 h. Baseline lesion volume was determined by diffusion-weighted MRI prior to reperfusion and final infarct volume determined by T2-weighted MRI at Day 7. Neurological function was assessed at Days 1, 3 and 7. Results Ischaemic lesion volume decreased between Days 1 and 7: a 50% reduction was observed for the RibAdeAll group, 38% for the RibAde group and 18% in the animals that received saline. Reductions in lesion size in treatment groups were accompanied by a trend for faster functional recovery. Conclusion These data support the potential use of ribose, adenine and allopurinol in the treatment of cerebral ischaemic injury, especially since all compounds have been used in man.
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Affiliation(s)
- Kiterie M E Faller
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Joshua Leach
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Pamela Johnston
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Vallatos A, Gilmour L, Chalmers AJ, Holmes WM. Multiple boli arterial spin labeling for high signal-to-noise rodent brain perfusion imaging. Magn Reson Med 2017; 79:1020-1030. [PMID: 28516482 DOI: 10.1002/mrm.26706] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/18/2017] [Accepted: 03/19/2017] [Indexed: 12/30/2022]
Abstract
PURPOSE A systematic method is proposed for optimizing a promising preclinical arterial spin labeling (ASL) sequence based on the use of a train of adiabatic radiofrequency pulses labeling successive boli of blood water. METHODS The sequence optimization is performed and evaluated using brain imaging experiments in mice and in rats. It involves the investigation of several parameters, ranging from the number of adiabatic pulses and labeling duration to the properties of the adiabatic hyperbolic secant pulses (ie, amplitude and frequency modulation). RESULTS Species-dependent parameters are identified, allowing for robust fast optimization protocols to be introduced. The resulting optimized multiple boli ASL (mbASL) sequence provides with significantly higher average signal-to-noise ratios (SNR) per voxel volume than currently encountered in ASL studies (278 mm-3 in mice and 172 mm-3 in rats). Comparing with the commonly used flow-sensitive alternating inversion recovery technique (FAIR), mbASL-to-FAIR SNR ratios reach 203% for mice and 725% for rats. CONCLUSION When properly optimized, mbASL can offer a robust, high SNR ASL alternative for rodent brain perfusion studies Magn Reson Med 79:1020-1030, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom
| | - Lesley Gilmour
- Wolfson Wohl Translational Cancer Research Center, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anthony J Chalmers
- Wolfson Wohl Translational Cancer Research Center, Institute of Cancer Sciences, University of Glasgow, Glasgow, United Kingdom
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom
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Merrifield GD, Mullin J, Gallagher L, Tucker C, Jansen MA, Denvir M, Holmes WM. Rapid and recoverable in vivo magnetic resonance imaging of the adult zebrafish at 7T. Magn Reson Imaging 2017; 37:9-15. [PMID: 27751860 PMCID: PMC5344283 DOI: 10.1016/j.mri.2016.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/27/2016] [Accepted: 10/05/2016] [Indexed: 12/31/2022]
Abstract
Increasing scientific interest in the zebrafish as a model organism across a range of biomedical and biological research areas raises the need for the development of in vivo imaging tools appropriate to this subject. Development of the embryonic and early stage forms of the subject can currently be assessed using optical based techniques due to the transparent nature of the species at these early stages. However this is not an option during the juvenile and adult stages when the subjects become opaque. Magnetic resonance imaging (MRI) techniques would allow for the longitudinal and non-invasive assessment of development and health in these later life stages. However, the small size of the zebrafish and its aquatic environment represent considerable challenges for the technique. We have developed a suitable flow cell system that incorporates a dedicated MRI imaging coil to solve these challenges. The system maintains and monitors a zebrafish during a scan and allows for it to be fully recovered. The imaging properties of this system compare well with those of other preclinical MRI coils used in rodent models. This enables the rapid acquisition of MRI data which are comparable in terms of quality and acquisition time. This would allow the many unique opportunities of the zebrafish as a model organism to be combined with the benefits of non-invasive MRI.
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Affiliation(s)
- Gavin D Merrifield
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - James Mullin
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - Lindsay Gallagher
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - Carl Tucker
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - Maurits A Jansen
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - Martin Denvir
- University/BHF Centre for Cardiovascular Science, University of Edinburgh, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.
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Lavery CA, Kurowska‐Stolarska M, Holmes WM, Donnelly I, Caslake M, Collier A, Baker AH, Miller AM. miR-34a(-/-) mice are susceptible to diet-induced obesity. Obesity (Silver Spring) 2016; 24:1741-51. [PMID: 27377585 PMCID: PMC4979678 DOI: 10.1002/oby.21561] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 04/07/2016] [Accepted: 04/26/2016] [Indexed: 01/13/2023]
Abstract
OBJECTIVE MicroRNA (miR)-34a regulates inflammatory pathways, and increased transcripts have been observed in serum and subcutaneous adipose of subjects who have obesity and type 2 diabetes. Therefore, the role of miR-34a in adipose tissue inflammation and lipid metabolism in murine diet-induced obesity was investigated. METHODS Wild-type (WT) and miR-34a(-/-) mice were fed chow or high-fat diet (HFD) for 24 weeks. WT and miR-34a(-/-) bone marrow-derived macrophages were cultured in vitro with macrophage colony-stimulating factor (M-CSF). Brown and white preadipocytes were cultured from the stromal vascular fraction (SVF) of intrascapular brown and epididymal white adipose tissue (eWAT), with rosiglitazone. RESULTS HFD-fed miR-34a(-/-) mice were significantly heavier with a greater increase in eWAT weight than WT. miR-34a(-/-) eWAT had a smaller adipocyte area, which significantly increased with HFD. miR-34a(-/-) eWAT showed basal increases in Cd36, Hmgcr, Lxrα, Pgc1α, and Fasn. miR-34a(-/-) intrascapular brown adipose tissue had basal reductions in c/ebpα and c/ebpβ, with in vitro miR-34a(-/-) white adipocytes showing increased lipid content. An F4/80(high) macrophage population was present in HFD miR-34a(-/-) eWAT, with increased IL-10 transcripts and serum IL-5 protein. Finally, miR-34a(-/-) bone marrow-derived macrophages showed an ablated CXCL1 response to tumor necrosis factor-α. CONCLUSIONS These findings suggest a multifactorial role of miR-34a in controlling susceptibility to obesity, by regulating inflammatory and metabolic pathways.
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Affiliation(s)
- Christopher A. Lavery
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUK
| | - Mariola Kurowska‐Stolarska
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUK
| | - William M. Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of GlasgowGlasgowUK
| | - Iona Donnelly
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUK
| | - Muriel Caslake
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUK
| | - Andrew Collier
- Ayr Hospital, National Health Service: Ayrshire & ArranAyrUK
| | - Andrew H. Baker
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUK
| | - Ashley M. Miller
- Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary and Life Sciences, University of GlasgowGlasgowUK
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Shukla MN, Vallatos A, Phoenix VR, Holmes WM. Accurate phase-shift velocimetry in rock. J Magn Reson 2016; 267:43-53. [PMID: 27111139 DOI: 10.1016/j.jmr.2016.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Spatially resolved Pulsed Field Gradient (PFG) velocimetry techniques can provide precious information concerning flow through opaque systems, including rocks. This velocimetry data is used to enhance flow models in a wide range of systems, from oil behaviour in reservoir rocks to contaminant transport in aquifers. Phase-shift velocimetry is the fastest way to produce velocity maps but critical issues have been reported when studying flow through rocks and porous media, leading to inaccurate results. Combining PFG measurements for flow through Bentheimer sandstone with simulations, we demonstrate that asymmetries in the molecular displacement distributions within each voxel are the main source of phase-shift velocimetry errors. We show that when flow-related average molecular displacements are negligible compared to self-diffusion ones, symmetric displacement distributions can be obtained while phase measurement noise is minimised. We elaborate a complete method for the production of accurate phase-shift velocimetry maps in rocks and low porosity media and demonstrate its validity for a range of flow rates. This development of accurate phase-shift velocimetry now enables more rapid and accurate velocity analysis, potentially helping to inform both industrial applications and theoretical models.
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Affiliation(s)
- Matsyendra Nath Shukla
- School of Geographical and Earth Sciences, University of Glasgow, United Kingdom; Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom
| | - Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom.
| | - Vernon R Phoenix
- School of Geographical and Earth Sciences, University of Glasgow, United Kingdom
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom
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Baskerville TA, Macrae IM, Holmes WM, McCabe C. The influence of gender on 'tissue at risk' in acute stroke: A diffusion-weighted magnetic resonance imaging study in a rat model of focal cerebral ischaemia. J Cereb Blood Flow Metab 2016; 36:381-6. [PMID: 26661149 PMCID: PMC4759665 DOI: 10.1177/0271678x15606137] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/31/2015] [Indexed: 11/17/2022]
Abstract
This is the first study to assess the influence of sex on the evolution of ischaemic injury and penumbra. Permanent middle cerebral artery occlusion was induced in male (n = 9) and female (n = 10) Sprague-Dawley rats. Diffusion-weighted imaging was acquired over 4 h and infarct determined from T2 images at 24 h post-permanent middle cerebral artery occlusion. Penumbra was determined retrospectively from serial apparent diffusion coefficient lesions and T2-defined infarct. Apparent diffusion coefficient lesion volume was significantly smaller in females from 0.5 to 4 h post permanent middle cerebral artery occlusion as was infarct volume. Penumbral volume, and its loss over time, was not significantly different despite the sex difference in acute and final lesion volumes.
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Affiliation(s)
- Tracey A Baskerville
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - Christopher McCabe
- Glasgow Experimental MRI Centre (GEMRIC), Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences (MVLS), University of Glasgow, Glasgow, UK
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Pawlikowski JS, Brock C, Chen SC, Al-Olabi L, Nixon C, McGregor F, Paine S, Chanudet E, Lambie W, Holmes WM, Mullin JM, Richmond A, Wu H, Blyth K, King A, Kinsler VA, Adams PD. Acute Inhibition of MEK Suppresses Congenital Melanocytic Nevus Syndrome in a Murine Model Driven by Activated NRAS and Wnt Signaling. J Invest Dermatol 2015; 135:2902. [DOI: 10.1038/jid.2015.230] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Merrifield GD, Mullin J, Gallagher L, Tucker C, Jansen MA, Denvir M, Holmes WM. 16 Developing cardiac magnetic resonance imaging in the live zebrafish. Heart 2015. [DOI: 10.1136/heartjnl-2015-308734.16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Pawlikowski JS, Brock C, Chen SC, Al-Olabi L, Nixon C, McGregor F, Paine S, Chanudet E, Lambie W, Holmes WM, Mullin JM, Richmond A, Wu H, Blyth K, King A, Kinsler VA, Adams PD. Acute Inhibition of MEK Suppresses Congenital Melanocytic Nevus Syndrome in a Murine Model Driven by Activated NRAS and Wnt Signaling. J Invest Dermatol 2015; 135:2093-2101. [PMID: 25815427 PMCID: PMC4539947 DOI: 10.1038/jid.2015.114] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/02/2015] [Accepted: 03/09/2015] [Indexed: 12/21/2022]
Abstract
Congenital melanocytic nevus (CMN) syndrome is the association of pigmented melanocytic nevi with extra-cutaneous features, classically melanotic cells within the central nervous system, most frequently caused by a mutation of NRAS codon 61. This condition is currently untreatable and carries a significant risk of melanoma within the skin, brain, or leptomeninges. We have previously proposed a key role for Wnt signaling in the formation of melanocytic nevi, suggesting that activated Wnt signaling may be synergistic with activated NRAS in the pathogenesis of CMN syndrome. Some familial pre-disposition suggests a germ-line contribution to CMN syndrome, as does variability of neurological phenotypes in individuals with similar cutaneous phenotypes. Accordingly, we performed exome sequencing of germ-line DNA from patients with CMN to reveal rare or undescribed Wnt-signaling alterations. A murine model harboring activated NRAS(Q61K) and Wnt signaling in melanocytes exhibited striking features of CMN syndrome, in particular neurological involvement. In the first model of treatment for this condition, these congenital, and previously assumed permanent, features were profoundly suppressed by acute post-natal treatment with a MEK inhibitor. These data suggest that activated NRAS and aberrant Wnt signaling conspire to drive CMN syndrome. Post-natal MEK inhibition is a potential candidate therapy for patients with this debilitating condition.
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Affiliation(s)
- Jeffrey S Pawlikowski
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK; Beatson Institute for Cancer Research, Glasgow, UK; Current address: Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Claire Brock
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK; Beatson Institute for Cancer Research, Glasgow, UK
| | - Sheau-Chiann Chen
- Center for Quantitative Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Lara Al-Olabi
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Colin Nixon
- Beatson Institute for Cancer Research, Glasgow, UK
| | | | - Simon Paine
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | | | - Wendy Lambie
- Beatson Institute for Cancer Research, Glasgow, UK
| | - William M Holmes
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - James M Mullin
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Ann Richmond
- Department of Veterans Affairs, Vanderbilt University Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee, USA; Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Hong Wu
- Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Karen Blyth
- Beatson Institute for Cancer Research, Glasgow, UK
| | - Ayala King
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Veronica A Kinsler
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK; Pediatric Dermatology, Great Ormond St Hospital, London, UK.
| | - Peter D Adams
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK; Beatson Institute for Cancer Research, Glasgow, UK.
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Murtha LA, McLeod DD, Pepperall D, McCann SK, Beard DJ, Tomkins AJ, Holmes WM, McCabe C, Macrae IM, Spratt NJ. Intracranial pressure elevation after ischemic stroke in rats: cerebral edema is not the only cause, and short-duration mild hypothermia is a highly effective preventive therapy. J Cereb Blood Flow Metab 2015; 35:592-600. [PMID: 25515213 PMCID: PMC4420875 DOI: 10.1038/jcbfm.2014.230] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 01/25/2023]
Abstract
In both the human and animal literature, it has largely been assumed that edema is the primary cause of intracranial pressure (ICP) elevation after stroke and that more edema equates to higher ICP. We recently demonstrated a dramatic ICP elevation 24 hours after small ischemic strokes in rats, with minimal edema. This ICP elevation was completely prevented by short-duration moderate hypothermia soon after stroke. Here, our aims were to determine the importance of edema in ICP elevation after stroke and whether mild hypothermia could prevent the ICP rise. Experimental stroke was performed in rats. ICP was monitored and short-duration mild (35 °C) or moderate (32.5 °C) hypothermia, or normothermia (37 °C) was induced after stroke onset. Edema was measured in three studies, using wet-dry weight calculations, T2-weighted magnetic resonance imaging, or histology. ICP increased 24 hours after stroke onset in all normothermic animals. Short-duration mild or moderate hypothermia prevented this rise. No correlation was seen between ΔICP and edema or infarct volumes. Calculated rates of edema growth were orders of magnitude less than normal cerebrospinal fluid production rates. These data challenge current concepts and suggest that factors other than cerebral edema are the primary cause of the ICP elevation 24 hours after stroke onset.
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Affiliation(s)
- Lucy A Murtha
- 1] University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia [2] Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Damian D McLeod
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Debbie Pepperall
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Sarah K McCann
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Daniel J Beard
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - Amelia J Tomkins
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Christopher McCabe
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Neil J Spratt
- University of Newcastle and Hunter Medical Research Institute, New Lambton, New South Wales, Australia
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Wetterling F, Gallagher L, Mullin J, Holmes WM, McCabe C, Macrae IM, Fagan AJ. Sodium-23 magnetic resonance imaging has potential for improving penumbra detection but not for estimating stroke onset time. J Cereb Blood Flow Metab 2015; 35:103-10. [PMID: 25335803 PMCID: PMC4294399 DOI: 10.1038/jcbfm.2014.174] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 08/18/2014] [Accepted: 09/17/2014] [Indexed: 02/06/2023]
Abstract
Tissue sodium concentration increases in irreversibly damaged (core) tissue following ischemic stroke and can potentially help to differentiate the core from the adjacent hypoperfused but viable penumbra. To test this, multinuclear hydrogen-1/sodium-23 magnetic resonance imaging (MRI) was used to measure the changing sodium signal and hydrogen-apparent diffusion coefficient (ADC) in the ischemic core and penumbra after rat middle cerebral artery occlusion (MCAO). Penumbra and core were defined from perfusion imaging and histologically defined irreversibly damaged tissue. The sodium signal in the core increased linearly with time, whereas the ADC rapidly decreased by >30% within 20 minutes of stroke onset, with very little change thereafter (0.5-6 hours after MCAO). Previous reports suggest that the time point at which tissue sodium signal starts to rise above normal (onset of elevated tissue sodium, OETS) represents stroke onset time (SOT). However, extrapolating core data back in time resulted in a delay of 72 ± 24 minutes in OETS compared with actual SOT. At the OETS in the core, penumbra sodium signal was significantly decreased (88 ± 6%, P=0.0008), whereas penumbra ADC was not significantly different (92 ± 18%, P=0.2) from contralateral tissue. In conclusion, reduced sodium-MRI signal may serve as a viability marker for penumbra detection and can complement hydrogen ADC and perfusion MRI in the time-independent assessment of tissue fate in acute stroke patients.
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Affiliation(s)
- Friedrich Wetterling
- Department of Psychiatry, School of Medicine, Trinity College, The University of Dublin, College Green, Dublin, Ireland
| | - Lindsay Gallagher
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Jim Mullin
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Chris McCabe
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - I Mhairi Macrae
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Andrew J Fagan
- Centre for Advanced Medical Imaging, St James's Hospital/Trinity College Dublin, Dublin, Ireland
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Murray KN, Girard S, Holmes WM, Parkes LM, Williams SR, Parry-Jones AR, Allan SM. Systemic inflammation impairs tissue reperfusion through endothelin-dependent mechanisms in cerebral ischemia. Stroke 2014; 45:3412-9. [PMID: 25228257 DOI: 10.1161/strokeaha.114.006613] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE Systemic inflammation contributes to diverse acute and chronic brain pathologies, and extensive evidence implicates inflammation in stroke susceptibility and poor outcome. Here we investigate whether systemic inflammation alters cerebral blood flow during reperfusion after experimental cerebral ischemia. METHODS Serial diffusion and perfusion-weighted MRI was performed after reperfusion in Wistar rats given systemic (intraperitoneal) interleukin-1β or vehicle before 60-minute transient middle cerebral artery occlusion. The expression and location of endothelin-1 was assessed by polymerase chain reaction, ELISA, and immunofluorescence. RESULTS Systemic interleukin-1 caused a severe reduction in cerebral blood flow and increase in infarct volume compared with vehicle. Restriction in cerebral blood flow was observed alongside activation of the cerebral vasculature and upregulation of the vasoconstricting peptide endothelin-1 in the ischemic penumbra. A microthrombotic profile was also observed in the vasculature of rats receiving interleukin-1. Blockade of endothelin-1 receptors reversed this hypoperfusion, reduced tissue damage, and improved functional outcome. CONCLUSIONS These data suggest patients with a raised inflammatory profile may have persistent deficits in perfusion after reopening of an occluded vessel. Future therapeutic strategies to interrupt the mechanism identified could lead to enhanced recovery of penumbra in patients with a heightened inflammatory burden and a better outcome after stroke.
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Affiliation(s)
- Katie N Murray
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.)
| | - Sylvie Girard
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.)
| | - William M Holmes
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.)
| | - Laura M Parkes
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.)
| | - Stephen R Williams
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.)
| | - Adrian R Parry-Jones
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.).
| | - Stuart M Allan
- From the Faculty of Life Sciences (K.N.M., S.M.A.) and Centre for Imaging Science (L.M.P., S.R.W.), University of Manchester, Manchester, United Kingdom; Sainte-Justine Hospital Research Centre, University of Montreal, Canada (S.G.); Glasgow Experimental MRI Centre, The University of Glasgow, Glasgow, United Kingdom (W.M.H.); and University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom (A.R.P.-J.)
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Holmes WM, Mannakee BK, Gutenkunst RN, Serio TR. Loss of amino-terminal acetylation suppresses a prion phenotype by modulating global protein folding. Nat Commun 2014; 5:4383. [PMID: 25023910 PMCID: PMC4140192 DOI: 10.1038/ncomms5383] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/13/2014] [Indexed: 01/08/2023] Open
Abstract
N-terminal acetylation is among the most ubiquitous of protein modifications in eukaryotes. While loss of N-terminal acetylation is associated with many abnormalities, the molecular basis of these effects is known for only a few cases, where acetylation of single factors has been linked to binding avidity or metabolic stability. In contrast, the impact of N-terminal acetylation for the majority of the proteome, and its combinatorial contributions to phenotypes, are unknown. Here, by studying the yeast prion [PSI+], an amyloid of the Sup35 protein, we show that loss of N-terminal acetylation promotes general protein misfolding, a redeployment of chaperones to these substrates, and a corresponding stress response. These proteostasis changes, combined with the decreased stability of unacetylated Sup35 amyloid, reduce the size of prion aggregates and reverse their phenotypic consequences. Thus, loss of N-terminal acetylation, and its previously unanticipated role in protein biogenesis, globally resculpts the proteome to create a unique phenotype.
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Affiliation(s)
- William M Holmes
- 1] Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 185 Meeting Street, Providence, Rhode Island 02912, USA [2]
| | - Brian K Mannakee
- Graduate Interdisciplinary Program in Statistics, University of Arizona, 1548 East Drachman Street, Tucson, Arizona 85721, USA
| | - Ryan N Gutenkunst
- Department of Molecular and Cellular Biology, University of Arizona, 1007 East Lowell Street, Tucson, Arizona 85721, USA
| | - Tricia R Serio
- 1] Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 185 Meeting Street, Providence, Rhode Island 02912, USA [2]
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Robertson CA, McCabe C, Lopez-Gonzalez MR, Deuchar GA, Dani K, Holmes WM, Muir KW, Santosh C, Macrae IM. Detection of ischemic penumbra using combined perfusion and T2* oxygen challenge imaging. Int J Stroke 2014; 10:42-50. [PMID: 25042078 PMCID: PMC4283703 DOI: 10.1111/ijs.12327] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 01/29/2014] [Accepted: 05/27/2014] [Indexed: 01/28/2023]
Abstract
Background Acute ischemic stroke is common and disabling, but there remains a paucity of acute treatment options and available treatment (thrombolysis) is underutilized. Advanced brain imaging, designed to identify viable hypoperfused tissue (penumbra), could target treatment to a wider population. Existing magnetic resonance imaging and computed tomography-based technologies are not widely used pending validation in ongoing clinical trials. T2* oxygen challenge magnetic resonance imaging, by providing a more direct readout of tissue viability, has the potential to identify more patients likely to benefit from thrombolysis – irrespective of time from stroke onset – and patients within and beyond the 4·5 h thrombolysis treatment window who are unlikely to benefit and are at an increased risk of hemorrhage. Aims This study employs serial multimodal imaging and voxel-based analysis to develop optimal data processing for T2* oxygen challenge penumbra assessment. Tissue in the ischemic hemisphere is compartmentalized into penumbra, ischemic core, or normal using T2* oxygen challenge (single threshold) or T2* oxygen challenge plus cerebral blood flow (dual threshold) data. Penumbra defined by perfusion imaging/apparent diffusion coefficient mismatch (dual threshold) is included for comparison. Methods Permanent middle cerebral artery occlusion was induced in male Sprague-Dawley rats (n = 6) prior to serial multimodal imaging: T2* oxygen challenge, diffusion-weighted and perfusion imaging (cerebral blood flow using arterial spin labeling). Results Across the different methods evaluated, T2* oxygen challenge combined with perfusion imaging most closely predicted 24 h infarct volume. Penumbra volume declined from one to four-hours post-stroke: mean ± SD, 77 ± 44 to 49 ± 37 mm3 (single T2* oxygen challenge-based threshold); 55 ± 41 to 37 ± 12 mm3 (dual T2* oxygen challenge/cerebral blood flow); 84 ± 64 to 42 ± 18 mm3 (dual cerebral blood flow/apparent diffusion coefficient), as ischemic core grew: 155 ± 37 to 211 ± 36 mm3 (single apparent diffusion coefficient threshold); 178 ± 56 to 205 ± 33 mm3 (dual T2* oxygen challenge/cerebral blood flow); 139 ± 30 to 168 ± 38 mm3 (dual cerebral blood flow/apparent diffusion coefficient). There was evidence of further lesion growth beyond four-hours (T2-defined edema-corrected infarct, 231 ± 19 mm3). Conclusions In conclusion, T2* oxygen challenge combined with perfusion imaging has advantages over alternative magnetic resonance imaging techniques for penumbra detection by providing serial assessment of available penumbra based on tissue viability.
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Affiliation(s)
- Craig A Robertson
- Centre for Stroke and Brain Imaging Research, Institute of Neuroscience and Psychology, College of Medicine, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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Abstract
Abstract others complementary, to resolve mis-folded proteins when they arise, ranging from refolding through the action of molecular chaperones to elimination through regulated proteolytic mechanisms. These protein quality control pathways are sufficient, under normal conditions, to maintain a functioning proteome, but in response to diverse environmental, genetic and/or stochastic events, protein mis-folding exceeds the corrective capacity of these pathways, leading to the accumulation of aggregates and ultimately toxicity. Particularly devastating examples of these effects include certain neurodegenerative diseases, such as Huntington's Disease, which are associated with the expansion of polyglutamine tracks in proteins. In these cases, protein mis-folding and aggregation are clear contributors to pathogenesis, but uncovering the precise mechanistic links between the two events remains an area of active research. Studies in the yeast Saccharomyces cerevisiae and other model systems have uncovered previously unanticipated complexity in aggregation pathways, the contributions of protein quality control processes to them and the cellular perturbations that result from them. Together these studies suggest that aggregate interactions and localization, rather than their size, are the crucial considerations in understanding the molecular basis of toxicity.
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Affiliation(s)
- William M Holmes
- Biology Department, College of the Holy Cross , Worcester, MA , USA and
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Douglas FJ, MacLaren DA, Tuna F, Holmes WM, Berry CC, Murrie M. Formation of octapod MnO nanoparticles with enhanced magnetic properties through kinetically-controlled thermal decomposition of polynuclear manganese complexes. Nanoscale 2014; 6:172-6. [PMID: 24220037 DOI: 10.1039/c3nr04832b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Polynuclear manganese complexes are used as precursors for the synthesis of manganese oxide nanoparticles (MnO NPs). Altering the thermal decomposition conditions can shift the nanoparticle product from spherical, thermodynamically-driven NPs to unusual, kinetically-controlled octapod structures. The resulting increased surface area profoundly alters the NP's surface-dependent magnetism and may have applications in nanomedicine.
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Affiliation(s)
- Fraser J Douglas
- WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
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Howard LE, Holmes WM, Ferrando S, Maclaine JS, Kelsh RN, Ramsey A, Abel RL, Cox JPL. Functional nasal morphology of chimaerid fishes. J Morphol 2013; 274:987-1009. [PMID: 23630172 DOI: 10.1002/jmor.20156] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 03/12/2013] [Accepted: 03/17/2013] [Indexed: 11/10/2022]
Abstract
Holocephalans (chimaeras) are a group of marine fishes comprising three families: the Callorhinchidae (callorhinchid fishes), the Rhinochimaeridae (rhinochimaerid fishes) and the Chimaeridae (chimaerid fishes). We have used X-ray microcomputed tomography and magnetic resonance imaging to characterise in detail the nasal anatomy of three species of chimaerid fishes: Chimaera monstrosa, C. phantasma and Hydrolagus colliei. We have shown that the nasal chamber of these three species is linked to the external environment by an incurrent channel and to the oral cavity by an excurrent channel via an oral groove. A protrusion of variable morphology is present on the medial wall of the incurrent channel in all three species, but is absent in members of the two other holocephalan families that we inspected. A third nasal channel, the lateral channel, functionally connects the incurrent nostril to the oral cavity, by-passing the nasal chamber. From anatomical reconstructions, we have proposed a model for the circulation of water, and therefore the transport of odorant, in the chimaerid nasal region. In this model, water could flow through the nasal region via the nasal chamber or the lateral channel. In either case, the direction of flow could be reversed. Circulation through the entire nasal region is likely to be driven primarily by the respiratory pump. We have identified several anatomical features that may segregate, distribute, facilitate and regulate flow in the nasal region and have considered the consequences of flow reversal. The non-sensory cilia lining the olfactory sensory channels appear to be mucus-propelling, suggesting that these cilia have a common protective role in cartilaginous fishes (sharks, rays and chimaeras). The nasal region of chimaerid fishes shows at least two adaptations to a benthic lifestyle, and suggests good olfactory sensitivity, with secondary folding enhancing the hypothetical flat sensory surface area by up to 70%.
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Affiliation(s)
- Lauren E Howard
- Department of Mineralogy, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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Ramanan B, Holmes WM, Sloan WT, Phoenix VR. Magnetic Resonance Imaging of Mass Transport and Structure Inside a Phototrophic Biofilm. Curr Microbiol 2013; 66:456-61. [DOI: 10.1007/s00284-012-0292-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 12/07/2012] [Indexed: 10/27/2022]
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Reid E, Graham D, Lopez-Gonzalez MR, Holmes WM, Macrae IM, McCabe C. Penumbra detection using PWI/DWI mismatch MRI in a rat stroke model with and without comorbidity: comparison of methods. J Cereb Blood Flow Metab 2012; 32:1765-77. [PMID: 22669479 PMCID: PMC3434632 DOI: 10.1038/jcbfm.2012.69] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Perfusion-diffusion (perfusion-weighted imaging (PWI)/diffusion-weighted imaging (DWI)) mismatch is used to identify penumbra in acute stroke. However, limitations in penumbra detection with mismatch are recognized, with a lack of consensus on thresholds, quantification and validation of mismatch. We determined perfusion and diffusion thresholds from final infarct in the clinically relevant spontaneously hypertensive stroke-prone (SHRSP) rat and its normotensive control strain, Wistar-Kyoto (WKY) and compared three methods for penumbra calculation. After permanent middle cerebral artery occlusion (MCAO) (WKY n=12, SHRSP n=15), diffusion-weighted (DWI) and perfusion-weighted (PWI) images were obtained for 4 hours post stroke and final infarct determined at 24 hours on T(2) scans. The PWI/DWI mismatch was calculated from volumetric assessment (perfusion deficit volume minus apparent diffusion coefficient (ADC)-defined lesion volume) or spatial assessment of mismatch area on each coronal slice. The ADC-derived lesion growth provided the third, retrospective measure of penumbra. At 1 hour after MCAO, volumetric mismatch detected smaller volumes of penumbra in both strains (SHRSP: 31 ± 50 mm(3), WKY: 22 ± 59 mm(3), mean ± s.d.) compared with spatial assessment (SHRSP: 36 ± 15 mm(3), WKY: 43 ± 43 mm(3)) and ADC lesion expansion (SHRSP: 41 ± 45 mm(3), WKY: 65 ± 41 mm(3)), although these differences were not statistically significant. Spatial assessment appears most informative, using both diffusion and perfusion data, eliminating the influence of negative mismatch and allowing the anatomical location of penumbra to be assessed at given time points after stroke.
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Affiliation(s)
- Emma Reid
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Baskerville TA, McCabe C, Weir CJ, Macrae IM, Holmes WM. Noninvasive MRI measurement of CBF: evaluating an arterial spin labelling sequence with 99mTc-HMPAO CBF autoradiography in a rat stroke model. J Cereb Blood Flow Metab 2012; 32:973-7. [PMID: 22472604 PMCID: PMC3367221 DOI: 10.1038/jcbfm.2012.19] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Arterial spin labelling (ASL) is increasingly available for noninvasive cerebral blood flow (CBF) measurement in stroke research. Here, a pseudo-continuous ASL technique (pCASL) was evaluated against (99m)Tc-D, L-hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) autoradiography in a rat stroke model. The (99m)Tc-HMPAO was injected (intravenously, 225 MBq) during pCASL acquisition. The pCASL and (99m)Tc-HMPAO autoradiography CBF measures, relative to the contralateral hemisphere, were in good agreement across the spectrum of flow values in normal and ischemic tissues. The pCASL-derived quantitative regional CBF values (contralateral: 157 to 177 mL/100 g per minute; ipsilateral: 9 to 104 mL/100 g per minute) were consistent with the literature values. The data show the potential utility of pCASL for CBF assessment in a rat stroke model.
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Affiliation(s)
- Tracey A Baskerville
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, Scotland
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Holmes WM, Lopez-Gonzalez MR, Gallagher L, Deuchar GA, Macrae IM, Santosh C. Novel MRI detection of the ischemic penumbra: direct assessment of metabolic integrity. NMR Biomed 2012; 25:295-304. [PMID: 21751274 DOI: 10.1002/nbm.1748] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 04/12/2011] [Accepted: 04/17/2011] [Indexed: 05/31/2023]
Abstract
We describe a novel magnetic resonance imaging technique to directly assess the metabolic integrity of penumbral tissue following stroke. For ischemically stressed tissue to be salvageable, it has to be capable of recovering aerobic metabolism (in place of anaerobic metabolism) on reperfusion. We probed ischemic brain tissue by altering the rate of oxygen delivery using a challenge of 100% oxygen ventilation. Any change from anaerobic to aerobic metabolism should alter the rate of lactate production and hence, levels of tissue lactate. Stroke was induced by permanent middle cerebral artery occlusion in rats. In Series 1 (n = 6), changes in tissue lactate during and following 100% oxygen challenge were monitored using (1)H magnetic resonance spectroscopy (MRS). Diffusion weighted imaging (DWI) and perfusion weighted imaging (PWI) were used to locate MRS voxels within the ischemic core, the homotopic contralateral striatum and within PWI/DWI mismatch (i.e. presumed penumbra). After 20 min of oxygen, lactate signal change was -16.1 ± 8.8% (mean ± SD) in PWI/DWI mismatch, +2.8 ± 5.1% in the ischemic core, and -0.6 ± 7.6% in the contralateral striatum. Return to air ventilation for 20 min resulted in a reversal, with lactate increasing by 46 ± 25.3% in the PWI/DWI mismatch, 6.6 ± 6.2% in the ischemic core, and -5 ± 11.4% in the contralateral striatum. In Series 2 (n = 6), a novel form of spectroscopic imaging was used to acquire lactate change maps to spatially identify regions of lactate change within the ischemic brain. This technique has potential clinical utility by identifying tissue that displays anaerobic metabolism capable of recovering aerobic metabolism when oxygen delivery is increased, which could provide a more precise assessment of penumbra.
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Affiliation(s)
- William M Holmes
- Glasgow Experimental MRI Centre, Division of Clinical Neuroscience, Faculty of Medicine, University of Glasgow, G61 1QH, Scotland, UK.
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Ramanan B, Holmes WM, Sloan WT, Phoenix VR. Investigation of nanoparticle transport inside coarse-grained geological media using magnetic resonance imaging. Environ Sci Technol 2012; 46:360-366. [PMID: 22091923 DOI: 10.1021/es2012726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Quantifying nanoparticle (NP) transport inside saturated porous geological media is imperative for understanding their fate in a range of natural and engineered water systems. While most studies focus upon finer grained systems representative of soils and aquifers, very few examine coarse-grained systems representative of riverbeds and gravel based sustainable urban drainage systems. In this study, we investigated the potential of magnetic resonance imaging (MRI) to image transport behaviors of nanoparticles (NPs) through a saturated coarse-grained system. MRI successfully imaged the transport of superparamagnetic NPs, inside a porous column composed of quartz gravel using T(2)-weighted images. A calibration protocol was then used to convert T(2)-weighted images into spatially resolved quantitative concentration maps of NPs at different time intervals. Averaged concentration profiles of NPs clearly illustrates that transport of a positively charged amine-functionalized NP within the column was slower compared to that of a negatively charged carboxyl-functionalized NP, due to electrostatic attraction between positively charged NP and negatively charged quartz grains. Concentration profiles of NPs were then compared with those of a convection-dispersion model to estimate coefficients of dispersivity and retardation. For the amine functionalized NPs (which exhibited inhibited transport), a better model fit was obtained when permanent attachment (deposition) was incorporated into the model as opposed to nonpermanent attachment (retardation). This technology can be used to further explore transport processes of NPs inside coarse-grained porous media, either by using the wide range of commercially available (super)paramagnetically tagged NPs or by using custom-made tagged NPs.
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Affiliation(s)
- B Ramanan
- School of Geographical and Earth Sciences, Gregory Building, University of Glasgow, Glasgow G12 8QQ, UK
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Ruest T, Holmes WM, Barrie JA, Griffiths IR, Anderson TJ, Dewar D, Edgar JM. High-resolution diffusion tensor imaging of fixed brain in a mouse model of Pelizaeus-Merzbacher disease: comparison with quantitative measures of white matter pathology. NMR Biomed 2011; 24:1369-1379. [PMID: 22223367 DOI: 10.1002/nbm.1700] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 01/25/2011] [Accepted: 01/27/2011] [Indexed: 05/31/2023]
Abstract
Diffusion tensor imaging (DTI) is a powerful technique for the noninvasive assessment of the central nervous system. To facilitate the application of this technique to in vivo studies, we characterised a mouse model of the leukodystrophy, Pelizaeus-Merzbacher disease (PMD), comparing high-resolution ex vivo DTI findings with quantitative histological analysis of selected areas of the brain. The mice used in this study (Plp1-transgenic) carry transgenic copies of the Plp1 gene and are models for PMD as a result of gene duplication. Plp1 transgenic mice display a mild ataxia and experience frequent seizures around the time at which they were imaged. Axial (λ(1) ) and radial (RD) diffusivities and fractional anisotropy (FA) data were analysed using an exploratory whole-brain voxel-based method, a voxel-based approach using tract-based spatial statistics (TBSS), and by application of conventional region of interest (ROI) analyses to selected white matter tracts. Raw t value maps and TBSS analyses indicated widespread changes throughout the brain of Plp1-transgenic mice compared with the wild-type. ROI analyses of the corpus callosum, anterior commissure and hippocampal fimbria showed that FA was reduced significantly, whereas λ(1) and RD were increased significantly, in Plp1-transgenic mice compared with the wild-type. The DTI data derived from ROI analyses were subsequently compared with histological measures taken in the same regions. These revealed an almost complete absence of myelin, preservation of axons, marked astrocytosis and increased or unchanged cell densities. These data contribute to our growing understanding of the basis of anisotropic water diffusion in the normal and diseased nervous system.
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Affiliation(s)
- Torsten Ruest
- Institute of Neuroscience and Psychology and Glasgow Experimental Magnetic Resonance Imaging Centre, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Robertson CA, McCabe C, Gallagher L, Lopez-Gonzalez MDR, Holmes WM, Condon B, Muir KW, Santosh C, Macrae IM. Stroke penumbra defined by an MRI-based oxygen challenge technique: 1. Validation using [14C]2-deoxyglucose autoradiography. J Cereb Blood Flow Metab 2011; 31:1778-87. [PMID: 21559032 PMCID: PMC3154682 DOI: 10.1038/jcbfm.2011.66] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Accurate identification of ischemic penumbra will improve stroke patient selection for reperfusion therapies and clinical trials. Current magnetic resonance imaging (MRI) techniques have limitations and lack validation. Oxygen challenge T(2)(*) MRI (T(2)(*) OC) uses oxygen as a biotracer to detect tissue metabolism, with penumbra displaying the greatest T(2)(*) signal change during OC. [(14)C]2-deoxyglucose (2-DG) autoradiography was combined with T(2)(*) OC to determine metabolic status of T(2)(*)-defined penumbra. Permanent middle cerebral artery occlusion was induced in anesthetized male Sprague-Dawley rats (n=6). Ischemic injury and perfusion deficit were determined by diffusion- and perfusion-weighted imaging, respectively. At 147 ± 32 minutes after stroke, T(2)(*) signal change was measured during a 5-minute 100% OC, immediately followed by 125 μCi/kg 2-DG, intravenously. Magnetic resonance images were coregistered with the corresponding autoradiograms. Regions of interest were located within ischemic core, T(2)(*)-defined penumbra, equivalent contralateral structures, and a region of hyperglycolysis. A T(2)(*) signal increase of 9.22% ± 3.9% (mean ± s.d.) was recorded in presumed penumbra, which displayed local cerebral glucose utilization values equivalent to contralateral cortex. T(2)(*) signal change was negligible in ischemic core, 3.2% ± 0.78% in contralateral regions, and 1.41% ± 0.62% in hyperglycolytic tissue, located outside OC-defined penumbra and within the diffusion abnormality. The results support the utility of OC-MRI to detect viable penumbral tissue following stroke.
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Affiliation(s)
- Craig A Robertson
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
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Holmes WM, Cotton R, Xuan VB, Rygg AD, Craven BA, Abel RL, Slack R, Cox JPL. Three-dimensional structure of the nasal passageway of a hagfish and its implications for olfaction. Anat Rec (Hoboken) 2011; 294:1045-56. [PMID: 21538925 DOI: 10.1002/ar.21382] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 01/10/2011] [Accepted: 02/10/2011] [Indexed: 11/08/2022]
Abstract
From high-resolution (65 μm) data acquired by magnetic resonance imaging, we have reconstructed the nasal passageway of a single adult hagfish specimen (probably Eptatretus stoutii). We have used this reconstruction to investigate how the anatomy and morphometry of the nasal passageway influence the olfactory ability of the hagfish. We found that the long, broad section of the passageway preceding the nasal chamber will delay the response to an odor by 1-2 s. Diffusion of odorant to the olfactory epithelium, on which the olfactory sensitivity of an animal depends, will be favored by the relatively large surface area of the olfactory epithelium (∼140 mm(2) ) and a modest expansion in the nasal chamber. Oscillating flow (0.3-0.4 Hz) within the narrow (65-130 μm) sensory channels of the nasal chamber is laminar (Reynolds number ∼ 5) and quasi-steady (Womersley number generally less than one). Distribution of flow over the olfactory epithelium may be aided by: (a) a narrowing before the nasal chamber; (b) partial blockage of the nasal passageway by a protrusion on the central olfactory lamella; and (c) the inward inclination of the olfactory lamellae.
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Affiliation(s)
- William M Holmes
- Glasgow Experimental MRI Centre, Wellcome Surgical Institute, University of Glasgow, Glasgow G61 1QH, UK
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Moldrich RX, Mezzera C, Holmes WM, Goda S, Brookfield SJ, Rankin AJ, Barr E, Kurniawan N, Dewar D, Richards LJ, López-Bendito G, Iwata T. Fgfr3 regulates development of the caudal telencephalon. Dev Dyn 2011; 240:1586-99. [DOI: 10.1002/dvdy.22636] [Citation(s) in RCA: 17] [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] [Accepted: 03/18/2011] [Indexed: 11/11/2022] Open
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Dani KA, Santosh C, Brennan D, McCabe C, Holmes WM, Condon B, Hadley DM, Macrae IM, Shaw M, Muir KW. T2*-weighted magnetic resonance imaging with hyperoxia in acute ischemic stroke. Ann Neurol 2010; 68:37-47. [PMID: 20582987 DOI: 10.1002/ana.22032] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE We describe the first clinical application of transient hyperoxia ("oxygen challenge") during T2*-weighted magnetic resonance imaging (MRI), to detect differences in vascular deoxyhemoglobin between tissue compartments following stroke. METHODS Subjects with acute ischemic stroke were scanned with T2*-weighted MRI and oxygen challenge. For regions defined as infarct core (diffusion-weighted imaging lesion) and presumed penumbra (perfusion-diffusion mismatch [threshold = T(max) > or =4 seconds], or regions exhibiting diffusion lesion expansion at day 3), T2*-weighted signal intensity-time curves corresponding to the duration of oxygen challenge were generated. From these, the area under the curve, gradient of incline of the signal increase, time to maximum signal, and percentage signal change after oxygen challenge were measured. RESULTS We identified 25 subjects with stroke lesions >1ml. Eighteen subjects with good quality T2*-weighted signal intensity-time curves in the contralateral hemisphere were analyzed. Curves from the diffusion lesion had a smaller area under the curve, percentage signal change, and gradient of incline, and longer time to maximum signal (p < 0.05, n = 17) compared to normal tissue, which consistently showed signal increase during oxygen challenge. Curves in the presumed penumbral regions (n = 8) showed varied morphology, but at hyperacute time points (<8 hours) showed a tendency to greater percentage signal change. INTERPRETATION Differences in T2*-weighted signal intensity-time curves during oxygen challenge in brain regions with different pathophysiological states after stroke are likely to reflect differences in deoxyhemoglobin concentration, and therefore differences in metabolic activity. Despite its underlying complexities, this technique offers a possible novel mode of metabolic imaging in acute stroke.
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Affiliation(s)
- Krishna A Dani
- Division of Clinical Neurosciences, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
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Miller AM, Asquith DL, Hueber AJ, Anderson LA, Holmes WM, McKenzie AN, Xu D, Sattar N, McInnes IB, Liew FY. Interleukin-33 induces protective effects in adipose tissue inflammation during obesity in mice. Circ Res 2010; 107:650-8. [PMID: 20634488 DOI: 10.1161/circresaha.110.218867] [Citation(s) in RCA: 257] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RATIONALE Chronic low-grade inflammation involving adipose tissue likely contributes to the metabolic consequences of obesity. The cytokine interleukin (IL)-33 and its receptor ST2 are expressed in adipose tissue, but their role in adipose tissue inflammation during obesity is unclear. OBJECTIVE To examine the functional role of IL-33 in adipose tissues and investigate the effects on adipose tissue inflammation and obesity in vivo. METHODS AND RESULTS We demonstrate that treatment of adipose tissue cultures in vitro with IL-33 induced production of Th2 cytokines (IL-5, IL-13, IL-10) and reduced expression of adipogenic and metabolic genes. Administration of recombinant IL-33 to genetically obese diabetic (ob/ob) mice led to reduced adiposity, reduced fasting glucose and improved glucose and insulin tolerance. IL-33 also induced accumulation of Th2 cells in adipose tissue and polarization of adipose tissue macrophages toward an M2 alternatively activated phenotype (CD206(+)), a lineage associated with protection against obesity-related metabolic events. Furthermore, mice lacking endogenous ST2 fed high-fat diet had increased body weight and fat mass and impaired insulin secretion and glucose regulation compared to WT controls fed high-fat diet. CONCLUSIONS In conclusion, IL-33 may play a protective role in the development of adipose tissue inflammation during obesity.
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Affiliation(s)
- Ashley M Miller
- Division of Immunology, Infection and Inflammation, GBRC, University of Glasgow, Glasgow, United Kingdom.
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Holmes WM, McCabe C, Mullin JM, Condon B, Bain MM. In ovo non-invasive quantification of the myocardial function and mass of chick embryos using magnetic resonance imaging. NMR Biomed 2009; 22:745-752. [PMID: 19322809 DOI: 10.1002/nbm.1386] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Magnetic resonance imaging (MRI) has evolved as one of the major non-invasive tools to study healthy and diseased hearts in animal models, especially rodent models. Even though, the chick embryo has long been used as a model for cardiovascular research, MRI has not yet been used for in vivo cardiac studies. Part of the reason for this is the difficulty in monitoring the ECG and respiration of the chick embryo in the magnet for gating purposes. To overcome this complication, this paper presents the use of retrospective Cine MRI to measure the cardiac function of chick embryos in ovo for the first time, without the need for respiratory or cardiac gating. The resulting left ventricular functional parameters, from six chick embryos at 20 days of incubation, were (mean +/- SD) EDV 69 +/- 15 microL, ESV 31 +/- 7 microL, SV 38 +/- 9 microL and EF 54.5 +/- 2%. The use of retrospective Cine MRI at earlier stages of development is also discussed and difficulties have been highlighted.
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Affiliation(s)
- William M Holmes
- GEMRIC, Wellcome Surgical Institute, University of Glasgow, Garscube Estate, Scotland, UK.
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Phoenix VR, Holmes WM. Magnetic resonance imaging of structure, diffusivity, and copper immobilization in a phototrophic biofilm. Appl Environ Microbiol 2008; 74:4934-43. [PMID: 18552186 PMCID: PMC2519349 DOI: 10.1128/aem.02783-07] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [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: 12/10/2007] [Accepted: 06/05/2008] [Indexed: 11/20/2022] Open
Abstract
Magnetic resonance imaging (MRI) was used to spatially resolve structure, water diffusion, and copper transport and fate in a phototrophic biofilm [corrected]. MRI was able to resolve considerable structural heterogeneity, ranging from classical laminations approximately 500 mum thick to structures with no apparent ordering. Pulsed-field gradient (PFG) analysis spatially resolved water diffusion coefficients which exhibited relatively little or no attenuation (diffusion coefficients ranged from 1.7 x 10(-9) m(2) s(-1) to 2.2 x 10(-9) m(2) s(-1)). The biofilm was then reacted with a 10-mg liter(-1) Cu(2+) solution, and transverse relaxation time parameter maps [corrected].were used to spatially and temporally map copper immobilization within the biofilm. Significantly, a calibration protocol similar to that used in biomedical research successfully quantified copper concentrations throughout the biofilm. Variations in Cu concentrations were controlled by the biofilm structure. Copper immobilization was most rapid (approximately 5 mg Cu liter(-1) h(-1)) over the first 20 to 30 h and then much slower for the remaining 60 h of the experiment. The transport of metal within the biofilm is controlled by both diffusion and immobilization. This was explored using a Bartlett and Gardner model which examined both diffusion and adsorption through a hypothetical film exhibiting properties similar to those of the phototrophic biofilm. Higher adsorption constants (K) resulted in longer lag times until the onset of immobilization at depth but higher actual adsorption rates. MRI and reaction transport models are versatile tools which can significantly improve our understanding of heavy metal immobilization in naturally occurring biofilms.
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Affiliation(s)
- V R Phoenix
- Department of Geographical and Earth Sciences, Gregory Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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Holmes WM, Maclellan S, Condon B, Dufès C, Evans TRJ, Uchegbu IF, Schätzlein AG. High-resolution 3D isotropic MR imaging of mouse flank tumours obtainedin vivowith solenoid RF micro-coil. Phys Med Biol 2007; 53:505-13. [DOI: 10.1088/0031-9155/53/2/015] [Citation(s) in RCA: 4] [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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Abstract
Using a combination of rheology and nuclear magnetic resonance (NMR) spectroscopy/velocimetry we demonstrate the existence of shear banding fluctuations under Couette flow of the micellar system 10% w/v cetylpyridinium chloride and sodium salicylate (CPyCl-NaSal) molar ratio 2 : 1 in 0.5 M NaCl in either HO or HO, using both time-averaged and real-time measurements. These shear banding fluctuations are consistent not only with the shear stress fluctuations observed in rheological measurements but also with fluctuations in the change of the constrained fraction of the amphiphile chain (Δ) observed in H-NMR spectroscopy experiments. Using H-NMR spectroscopy on a deuterated probe molecule (-decane) located in the wormlike micellar interior, direct measurement of the shear-induced nematic phase transition is reported.
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Affiliation(s)
- M R López-González
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, New Zealand
| | - W M Holmes
- Wellcome Surgical Institute, University of Glasgow, Glasgow, United KingdomG61 1QH
| | - P T Callaghan
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, New Zealand
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López-González MR, Holmes WM, Callaghan PT, Photinos PJ. Shear banding fluctuations and nematic order in wormlike micelles. Phys Rev Lett 2004; 93:268302. [PMID: 15698033 DOI: 10.1103/physrevlett.93.268302] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2004] [Indexed: 05/24/2023]
Abstract
Using rapid NMR velocimetry we demonstrate the existence of shear band fluctuations in the Couette flow of the wormlike micelle system, 10% w/v cetylpyridinium chloride and sodium salicylate (molar ratio 2:1) in 0.5 M 2H2O NaCl brine. We show that the fluctuations may be either quasirandom or periodic, the fluctuation spectrum being similar to that observed in the stress. Despite the equilibrium fluid being far from an isotropic-nematic transition, deuterium NMR shows that the onset of shear banding is associated with a nematic micellar state whose order parameter depends on shear rate.
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Affiliation(s)
- M R López-González
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, New Zealand
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Abstract
Pulsed magnetic field gradient stimulated echo NMR is used to investigate the simultaneous flow of two phases (an aqueous phase and an hydrocarbon phase) within a strongly water-wet sample of Fontainebleau sandstone. The Fontainebleau sandstone is prepared in increasing steady-state water saturations by a secondary imbibition process. The increase in the water saturation causes an increasing fraction of the oil phase (non-wetting phase) to become trapped within the sample. The stimulated echo dependence on the gradient pulse area, q, is used to derive the displacement probability, PX, for a fixed observation time. These displacement probabilities clearly show the progressive trapping of the hydrocarbon phase with increasing steady-state water saturations. Quantitative measurements of the fraction of the oil phase trapped were made from the echo attenuation function Edelta(q), both as a function of water saturation and observation time.
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Affiliation(s)
- William M Holmes
- School of Chemical and Physical Sciences, Victoria University, P.O. Box 600, Wellington, New Zealand
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