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Roeder BM, She X, Dakos AS, Moore B, Wicks RT, Witcher MR, Couture DE, Laxton AW, Clary HM, Popli G, Liu C, Lee B, Heck C, Nune G, Gong H, Shaw S, Marmarelis VZ, Berger TW, Deadwyler SA, Song D, Hampson RE. Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall of stimulus features and categories. Front Comput Neurosci 2024; 18:1263311. [PMID: 38390007 PMCID: PMC10881797 DOI: 10.3389/fncom.2024.1263311] [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: 07/19/2023] [Accepted: 01/19/2024] [Indexed: 02/24/2024] Open
Abstract
Objective Here, we demonstrate the first successful use of static neural stimulation patterns for specific information content. These static patterns were derived by a model that was applied to a subject's own hippocampal spatiotemporal neural codes for memory. Approach We constructed a new model of processes by which the hippocampus encodes specific memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of targeted content into short-term memory. A memory decoding model (MDM) of hippocampal CA3 and CA1 neural firing was computed which derives a stimulation pattern for CA1 and CA3 neurons to be applied during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task. Main results MDM electrical stimulation delivered to the CA1 and CA3 locations in the hippocampus during the sample phase of DMS trials facilitated memory of images from the DMS task during a delayed recognition (DR) task that also included control images that were not from the DMS task. Across all subjects, the stimulated trials exhibited significant changes in performance in 22.4% of patient and category combinations. Changes in performance were a combination of both increased memory performance and decreased memory performance, with increases in performance occurring at almost 2 to 1 relative to decreases in performance. Across patients with impaired memory that received bilateral stimulation, significant changes in over 37.9% of patient and category combinations was seen with the changes in memory performance show a ratio of increased to decreased performance of over 4 to 1. Modification of memory performance was dependent on whether memory function was intact or impaired, and if stimulation was applied bilaterally or unilaterally, with nearly all increase in performance seen in subjects with impaired memory receiving bilateral stimulation. Significance These results demonstrate that memory encoding in patients with impaired memory function can be facilitated for specific memory content, which offers a stimulation method for a future implantable neural prosthetic to improve human memory.
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Affiliation(s)
- Brent M Roeder
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Xiwei She
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Alexander S Dakos
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Bryan Moore
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Robert T Wicks
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
- Johns Hopkins Children's Center, Baltimore, MD, United States
| | - Mark R Witcher
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
- Virginia Tech Carilion School of Medicine and Research Institute, Roanoke, VA, United States
| | - Daniel E Couture
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Adrian W Laxton
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | | | - Gautam Popli
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Charles Liu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - Brian Lee
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - Christianne Heck
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - George Nune
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - Hui Gong
- Rancho Los Amigos National Rehabilitation Hospital, Los Angeles, CA, United States
| | - Susan Shaw
- Rancho Los Amigos National Rehabilitation Hospital, Los Angeles, CA, United States
| | - Vasilis Z Marmarelis
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Theodore W Berger
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Sam A Deadwyler
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Dong Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Robert E Hampson
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
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Lee RP, Bhimreddy M, Kim J, Wicks RT, Xu R, Bender M, Yang W, Sattari SA, Hung A, Jackson CM, Gonzalez LF, Huang J, Tamargo R, McDougall CG, Caplan JM. No Delayed Ruptures on Long-Term Follow-Up of a Case Series of Persistently Filling Saccular Internal Carotid Artery Aneurysms After Flow Diversion With the Pipeline Embolization Device. Neurosurgery 2023; 93:994-999. [PMID: 37255292 DOI: 10.1227/neu.0000000000002521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/20/2023] [Indexed: 06/01/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Flow diversion of intracranial aneurysms results in high occlusion rates. However, 10% to 20% remain persistently filling at 1 year. Often, these are retreated, but benefits of retreatment are not well established. A better understanding of the long-term rupture risk of persistently filling aneurysms after flow diversion is needed. METHODS Our institutional database of 974 flow diversion cases was queried for persistently filling saccular aneurysms of the clinoidal, ophthalmic, and communicating segments of the internal carotid artery treated with the pipeline embolization device (PED, Medtronic). Persistent filling was defined as continued flow into the aneurysm on 1 year catheter angiogram. The clinical record was queried for retreatments and delayed ruptures. Clinical follow-up was required for at least 2 years. RESULTS Ninety-four persistent aneurysms were identified. The average untreated aneurysm size was 5.6 mm. A branch vessel originated separately in 55% of cases from the body of the aneurysm in 10.6% of cases and from the neck in 34% of cases. Eighteen percent of aneurysms demonstrated >95% filling at 1 year, and 61% were filling 5% to 95% of their original size. The mean follow-up time was 4.9 years, including 41 cases with >5 years. No retreatment was undertaken in 91.5% of aneurysms. There were no cases of delayed subarachnoid hemorrhage. CONCLUSION Among saccular internal carotid artery aneurysms treated with PED that demonstrated persistent aneurysm filling at 1 year, there were no instances of delayed rupture on long-term follow-up. These data suggest that observation may be appropriate for continued aneurysm filling at least in the first several years after PED placement.
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Affiliation(s)
- Ryan P Lee
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Meghana Bhimreddy
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Jennifer Kim
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Robert T Wicks
- Miami Neuroscience Institute, Baptist Health South Florida, Miami , Florida , USA
| | - Risheng Xu
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Matthew Bender
- Department of Neurosurgery, University of Rochester Medical Center, Rochester , New York , USA
| | - Wuyang Yang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Shahab Aldin Sattari
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Alice Hung
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Christopher M Jackson
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - L Fernando Gonzalez
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Judy Huang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Rafael Tamargo
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
| | - Cameron G McDougall
- Department of Neurosurgery, Swedish Neuroscience Institute, Seattle , Washington , USA
| | - Justin M Caplan
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore , Maryland , USA
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3
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Verscharen D, Wicks RT, Alexandrova O, Bruno R, Burgess D, Chen CHK, D’Amicis R, De Keyser J, de Wit TD, Franci L, He J, Henri P, Kasahara S, Khotyaintsev Y, Klein KG, Lavraud B, Maruca BA, Maksimovic M, Plaschke F, Poedts S, Reynolds CS, Roberts O, Sahraoui F, Saito S, Salem CS, Saur J, Servidio S, Stawarz JE, Štverák Š, Told D. A Case for Electron-Astrophysics. Exp Astron (Dordr) 2021; 54:473-519. [PMID: 36915623 PMCID: PMC9998602 DOI: 10.1007/s10686-021-09761-5] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 05/07/2021] [Indexed: 06/18/2023]
Abstract
The smallest characteristic scales, at which electron dynamics determines the plasma behaviour, are the next frontier in space and astrophysical plasma research. The analysis of astrophysical processes at these scales lies at the heart of the research theme of electron-astrophysics. Electron scales are the ultimate bottleneck for dissipation of plasma turbulence, which is a fundamental process not understood in the electron-kinetic regime. In addition, plasma electrons often play an important role for the spatial transfer of thermal energy due to the high heat flux associated with their velocity distribution. The regulation of this electron heat flux is likewise not understood. By focussing on these and other fundamental electron processes, the research theme of electron-astrophysics links outstanding science questions of great importance to the fields of space physics, astrophysics, and laboratory plasma physics. In this White Paper, submitted to ESA in response to the Voyage 2050 call, we review a selection of these outstanding questions, discuss their importance, and present a roadmap for answering them through novel space-mission concepts.
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Affiliation(s)
- Daniel Verscharen
- Mullard Space Science Laboratory, University College London, Dorking, UK
- Space Science Center, University of New Hampshire, Durham, NH USA
| | - Robert T. Wicks
- Mullard Space Science Laboratory, University College London, Dorking, UK
- Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle-upon-Tyne, UK
| | - Olga Alexandrova
- Laboratoire d’Études Spatiales et d’Instrumentation en Astrophysique, Observatoire de Paris-Meudon, Paris, France
| | - Roberto Bruno
- Instituto di Astrofisica e Planetologia Spaziali, INAF, Rome, Italy
| | - David Burgess
- School of Physics and Astronomy, Queen Mary University of London, London, UK
| | | | | | - Johan De Keyser
- Royal Belgian Institute for Space Aeronomy, Brussels, Belgium
| | - Thierry Dudok de Wit
- Laboratoire de Physique et Chimie de l’Environment et de l’Espace, CNRS, University of Orléans and CNES, Orléans, France
| | - Luca Franci
- School of Physics and Astronomy, Queen Mary University of London, London, UK
- Osservatorio Astrofisico di Arcetri, INAF, Firenze, Italy
| | - Jiansen He
- School of Earth and Space Sciences, Peking University, Beijing, China
| | - Pierre Henri
- Laboratoire de Physique et Chimie de l’Environment et de l’Espace, CNRS, University of Orléans and CNES, Orléans, France
- CNRS, UCA, OCA, Lagrange, Nice, France
| | - Satoshi Kasahara
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan
| | | | - Kristopher G. Klein
- Lunar and Planetary Laboratory and Department of Planetary Sciences, University of Arizona, Tucson, AZ USA
| | - Benoit Lavraud
- Laboratoire d’astrophysique de Bordeaux, Université de Bordeaux, CNRS, Pessac, France
- Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France
| | - Bennett A. Maruca
- Department of Physics and Astronomy, Bartol Research Institute, University of Delaware, Newark, DE USA
| | - Milan Maksimovic
- Laboratoire d’Études Spatiales et d’Instrumentation en Astrophysique, Observatoire de Paris-Meudon, Paris, France
| | | | - Stefaan Poedts
- Centre for Mathematical Plasma Astrophysics, KU Leuven, Leuven, Belgium
- Institute of Physics, University of Maria Curie-Skłodowska, Lublin, Poland
| | | | - Owen Roberts
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - Fouad Sahraoui
- Laboratoire de Physique des Plasmas, CNRS, École Polytechnique, Sorbonne Université, Observatoire de Paris-Meudon, Paris Saclay, Palaiseau, France
| | - Shinji Saito
- Space Environment Laboratory, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Chadi S. Salem
- Space Sciences Laboratory, University of California, Berkeley, CA USA
| | - Joachim Saur
- Institut für Geophysik und Meteorologie, University of Cologne, Cologne, Germany
| | - Sergio Servidio
- Department of Physics, Università della Calabria, Rende, Italy
| | | | - Štěpán Štverák
- Astronomical Institute and Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - Daniel Told
- Max Planck Institute for Plasma Physics, Garching, Germany
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Wilson LB, Brosius AL, Gopalswamy N, Nieves‐Chinchilla T, Szabo A, Hurley K, Phan T, Kasper JC, Lugaz N, Richardson IG, Chen CHK, Verscharen D, Wicks RT, TenBarge JM. A Quarter Century of Wind Spacecraft Discoveries. Rev Geophys 2021; 59:e2020RG000714. [PMCID: PMC9285980 DOI: 10.1029/2020rg000714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/29/2021] [Accepted: 03/05/2021] [Indexed: 06/13/2023]
Abstract
The Wind spacecraft, launched on November 1, 1994, is a critical element in NASA’s Heliophysics System Observatory (HSO)—a fleet of spacecraft created to understand the dynamics of the Sun‐Earth system. The combination of its longevity (>25 years in service), its diverse complement of instrumentation, and high resolution and accurate measurements has led to it becoming the “standard candle” of solar wind measurements. Wind has over 55 selectable public data products with over ∼1,100 total data variables (including OMNI data products) on SPDF/CDAWeb alone. These data have led to paradigm shifting results in studies of statistical solar wind trends, magnetic reconnection, large‐scale solar wind structures, kinetic physics, electromagnetic turbulence, the Van Allen radiation belts, coronal mass ejection topology, interplanetary and interstellar dust, the lunar wake, solar radio bursts, solar energetic particles, and extreme astrophysical phenomena such as gamma‐ray bursts. This review introduces the mission and instrument suites then discusses examples of the contributions by Wind to these scientific topics that emphasize its importance to both the fields of heliophysics and astrophysics. Wind has made seminal advances to the fields of astrophysics, turbulence, kinetic physics, magnetic reconnection, and the radiation belts Wind pioneered the study of the source and evolution of solar radio emissions below 15 MHz Wind revolutionized our understanding of coronal mass ejections, their internal magnetic structure, and evolution
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Affiliation(s)
- Lynn B. Wilson
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
| | - Alexandra L. Brosius
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
- Department of Meteorology and Atmospheric ScienceThe Pennsylvania State UniversityUniversity ParkPAUSA
| | | | | | - Adam Szabo
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
| | - Kevin Hurley
- Space Sciences LaboratoryUniversity of CaliforniaBerkeleyCAUSA
| | - Tai Phan
- Space Sciences LaboratoryUniversity of CaliforniaBerkeleyCAUSA
| | - Justin C. Kasper
- School of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborAnn ArborMIUSA
| | - Noé Lugaz
- Space Science CenterInstitute for the Study of EarthOceans, and SpaceUniversity of New HampshireDurhamNHUSA
- Department of PhysicsUniversity of New HampshireDurhamNHUSA
| | - Ian G. Richardson
- NASA Goddard Space Flight CenterHeliophysics Science DivisionGreenbeltMDUSA
- Department of AstronomyUniversity of MarylandCollege ParkMDUSA
| | | | - Daniel Verscharen
- Space Science CenterInstitute for the Study of EarthOceans, and SpaceUniversity of New HampshireDurhamNHUSA
- Mullard Space Science LaboratoryUniversity College LondonSurreyUK
| | - Robert T. Wicks
- Department of MathematicsPhysics and Electrical EngineeringNorthumbria University: Newcastle upon TyneTyne and WearUK
| | - Jason M. TenBarge
- University of MarylandCollege ParkMDUSA
- Department of Astrophysical SciencesPrinceton UniversityPrincetonNJUSA
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5
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Wicks RT, Nzou G, VanOstrand N, Mekky G, Seale S, Wicks E, Nechtman CM, Marrotte E, Makani V, Murphy SV, Seeds M, Jackson J, Atala A. 3D Neurovascular Spheroid for Assessing Hypoxia Induced Blood-Brain Barrier Dysfunction. Neurosurgery 2020. [DOI: 10.1093/neuros/nyaa447_293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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6
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Nzou G, Wicks RT, VanOstrand NR, Mekky GA, Seale SA, El-Taibany A, Wicks EE, Nechtman CM, Marrotte EJ, Makani VS, Murphy SV, Seeds MC, Jackson JD, Atala AJ. Author Correction: Multicellular 3D Neurovascular Unit Model for Assessing Hypoxia and Neuroinflammation Induced Blood-Brain Barrier Dysfunction. Sci Rep 2020; 10:20384. [PMID: 33204010 PMCID: PMC7673116 DOI: 10.1038/s41598-020-77348-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Goodwell Nzou
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA.
| | - Robert T Wicks
- Department of Neurology and Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Nicole R VanOstrand
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Gehad A Mekky
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA.,Zoology Department, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Stephanie A Seale
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Aya El-Taibany
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Elizabeth E Wicks
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Carl M Nechtman
- Department of Neurology and Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Eric J Marrotte
- Department of Neurology and Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Vishruti S Makani
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Sean V Murphy
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - M C Seeds
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - John D Jackson
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
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7
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Wicks RT, Witcher MR, Couture DE, Laxton AW, Popli G, Whitlow CT, Fetterhoff D, Dakos AS, Roeder BM, Deadwyler SA, Hampson RE. Hippocampal CA1 and CA3 neural recording in the human brain: validation of depth electrode placement through high-resolution imaging and electrophysiology. Neurosurg Focus 2020; 49:E5. [PMID: 32610296 DOI: 10.3171/2020.4.focus20164] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/16/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Intracranial human brain recordings typically utilize recording systems that do not distinguish individual neuron action potentials. In such cases, individual neurons are not identified by location within functional circuits. In this paper, verified localization of singly recorded hippocampal neurons within the CA3 and CA1 cell fields is demonstrated. METHODS Macro-micro depth electrodes were implanted in 23 human patients undergoing invasive monitoring for identification of epileptic seizure foci. Individual neurons were isolated and identified via extracellular action potential waveforms recorded via macro-micro depth electrodes localized within the hippocampus. A morphometric survey was performed using 3T MRI scans of hippocampi from the 23 implanted patients, as well as 46 normal (i.e., nonepileptic) patients and 26 patients with a history of epilepsy but no history of depth electrode placement, which provided average dimensions of the hippocampus along typical implantation tracks. Localization within CA3 and CA1 cell fields was tentatively assigned on the basis of recording electrode site, stereotactic positioning of the depth electrode in comparison with the morphometric survey, and postsurgical MRI. Cells were selected as candidate CA3 and CA1 principal neurons on the basis of waveform and firing rate characteristics and confirmed within the CA3-to-CA1 neural projection pathways via measures of functional connectivity. RESULTS Cross-correlation analysis confirmed that nearly 80% of putative CA3-to-CA1 cell pairs exhibited positive correlations compatible with feed-forward connection between the cells, while only 2.6% exhibited feedback (inverse) connectivity. Even though synchronous and long-latency correlations were excluded, feed-forward correlation between CA3-CA1 pairs was identified in 1071 (26%) of 4070 total pairs, which favorably compares to reports of 20%-25% feed-forward CA3-CA1 correlation noted in published animal studies. CONCLUSIONS This study demonstrates the ability to record neurons in vivo from specified regions and subfields of the human brain. As brain-machine interface and neural prosthetic research continues to expand, it is necessary to be able to identify recording and stimulation sites within neural circuits of interest.
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Affiliation(s)
| | | | | | | | | | | | - Dustin Fetterhoff
- 6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Alexander S Dakos
- 6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Brent M Roeder
- 6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Sam A Deadwyler
- 5Physiology and Pharmacology, and.,6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - Robert E Hampson
- 2Neurology.,5Physiology and Pharmacology, and.,6Program in Neuroscience, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
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8
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Nzou G, Wicks RT, VanOstrand NR, Mekky GA, Seale SA, El-Taibany A, Wicks EE, Nechtman CM, Marrotte EJ, Makani VS, Murphy SV, Seeds MC, Jackson JD, Atala AJ. Multicellular 3D Neurovascular Unit Model for Assessing Hypoxia and Neuroinflammation Induced Blood-Brain Barrier Dysfunction. Sci Rep 2020; 10:9766. [PMID: 32555384 PMCID: PMC7299970 DOI: 10.1038/s41598-020-66487-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/20/2020] [Indexed: 12/11/2022] Open
Abstract
The blood-brain barrier (BBB) is a dynamic component of the brain-vascular interface that maintains brain homeostasis and regulates solute permeability into brain tissue. The expression of tight junction proteins between adjacent endothelial cells and the presence of efflux proteins prevents entry of foreign substances into the brain parenchyma. BBB dysfunction, however, is evident in many neurological disorders including ischemic stroke, trauma, and chronic neurodegenerative diseases. Currently, major contributors to BBB dysfunction are not well understood. Here, we employed a multicellular 3D neurovascular unit organoid containing human brain microvascular endothelial cells, pericytes, astrocytes, microglia, oligodendrocytes and neurons to model the effects of hypoxia and neuroinflammation on BBB function. Organoids were cultured in hypoxic chamber with 0.1% O2 for 24 hours. Organoids cultured under this hypoxic condition showed increased permeability, pro-inflammatory cytokine production, and increased oxidative stress. The anti-inflammatory agents, secoisolariciresinol diglucoside and 2-arachidonoyl glycerol, demonstrated protection by reducing inflammatory cytokine levels in the organoids under hypoxic conditions. Through the assessment of a free radical scavenger and an anti-inflammatory endocannabinoid, we hereby report the utility of the model in drug development for drug candidates that may reduce the effects of ROS and inflammation under disease conditions. This 3D organoid model recapitulates characteristics of BBB dysfunction under hypoxic physiological conditions and when exposed to exogenous neuroinflammatory mediators and hence may have potential in disease modeling and therapeutic development.
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Affiliation(s)
- Goodwell Nzou
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA.
| | - Robert T Wicks
- Department of Neurology and Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Nicole R VanOstrand
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Gehad A Mekky
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
- Zoology Department, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Stephanie A Seale
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Aya El-Taibany
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Elizabeth E Wicks
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Carl M Nechtman
- Department of Neurology and Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Eric J Marrotte
- Department of Neurology and Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - Vishruti S Makani
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Sean V Murphy
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - M C Seeds
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - John D Jackson
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - Anthony J Atala
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
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9
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Nicolaou G, Livadiotis G, Wicks RT. On the Determination of Kappa Distribution Functions from Space Plasma Observations. Entropy (Basel) 2020; 22:e22020212. [PMID: 33285987 PMCID: PMC7516642 DOI: 10.3390/e22020212] [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] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/09/2020] [Accepted: 02/10/2020] [Indexed: 12/02/2022]
Abstract
The velocities of space plasma particles, often follow kappa distribution functions. The kappa index, which labels and governs these distributions, is an important parameter in understanding the plasma dynamics. Space science missions often carry plasma instruments on board which observe the plasma particles and construct their velocity distribution functions. A proper analysis of the velocity distribution functions derives the plasma bulk parameters, such as the plasma density, speed, temperature, and kappa index. Commonly, the plasma bulk density, velocity, and temperature are determined from the velocity moments of the observed distribution function. Interestingly, recent studies demonstrated the calculation of the kappa index from the speed (kinetic energy) moments of the distribution function. Such a novel calculation could be very useful in future analyses and applications. This study examines the accuracy of the specific method using synthetic plasma proton observations by a typical electrostatic analyzer. We analyze the modeled observations in order to derive the plasma bulk parameters, which we compare with the parameters we used to model the observations in the first place. Through this comparison, we quantify the systematic and statistical errors in the derived moments, and we discuss their possible sources.
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Affiliation(s)
- Georgios Nicolaou
- Department of Space and Climate Physics, Mullard Space Science Laboratory, University College London, Dorking, Surrey RH5 6NT, UK;
- Correspondence:
| | | | - Robert T. Wicks
- Department of Space and Climate Physics, Mullard Space Science Laboratory, University College London, Dorking, Surrey RH5 6NT, UK;
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10
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Zhao X, Wicks RT, Mulholland CB, Ducruet AF, Nakaji P. Left Far Lateral Craniotomy for Clipping of a Posterior Inferior Cerebellar Artery Aneurysm. J Neurol Surg B Skull Base 2019; 80:S341-S342. [PMID: 31750053 PMCID: PMC6863935 DOI: 10.1055/s-0039-1698825] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/25/2019] [Indexed: 11/15/2022] Open
Abstract
Objectives
The complex anatomical relationships of neurovascular structures at the craniovertebral junction make the clipping of a posterior inferior cerebellar artery (PICA) aneurysm surgically challenging. We demonstrate the clipping of a PICA aneurysm in the video.
Design, Setting, and Participant
A 65-year-old woman presented with a nonsymptomatic unruptured left PICA aneurysm; follow-up angiography showed an increase in its size. Preoperative angiography demonstrated a PICA aneurysm with the neck close to the origin of the PICA. A daughter sac of the aneurysm was also noted. A left far lateral approach was performed. The vagoaccessory triangle was exposed after opening the arachnoid membrane. The origin of the PICA and the aneurysm were revealed after exploration. The aneurysm neck was identified both proximally and distally. Two fenestrated clips were applied; subsequent indocyanine green (ICG) videoangiography demonstrated that the PICA was obstructed. One clip was adjusted, and repeated ICG videoangiography showed the PICA was patent. An endoscope was used before and after the clip application to better understand the anatomy of the aneurysm and inspect clip positions (
Fig. 1
).
Outcome
The patient was neurologically intact postoperatively and was discharged on postoperative day 4.
Conclusion
PICA aneurysms require careful treatment. Impingement of adjacent structures can cause severe complications. Lower cranial nerve damage can cause dysphagia, and compromised vertebral/PICA circulation can cause brainstem symptoms, such as Wallenberg's syndrome. Intraoperative ICG videoangiography should be used to evaluate vessel patency, and the endoscope should be used to fully inspect the aneurysm and evaluate the clip application.
The link to the video can be found at:
https://youtu.be/dKxFQTRA89g
.
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Affiliation(s)
- Xiaochun Zhao
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Robert T Wicks
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Celene B Mulholland
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Andrew F Ducruet
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Peter Nakaji
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
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11
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Wicks RT, Zhao X, Mulholland CB, Nakaji P. Far Lateral Craniotomy for Resection of Foramen Magnum Meningioma. J Neurol Surg B Skull Base 2019; 80:S355-S357. [PMID: 31750060 PMCID: PMC6864350 DOI: 10.1055/s-0039-1698828] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/25/2019] [Indexed: 11/16/2022] Open
Abstract
Objective
Foramen magnum meningiomas present a formidable challenge to resection due to frequent involvement of the lower cranial nerves and vertebrobasilar circulation. The video shows the use of a far lateral craniotomy to resect a foramen magnum meningioma.
Design, Setting, and Participant
A 49-year-old woman presented with neck pain and was found to have a large foramen magnum meningioma (
Fig. 1A, B
). Drilling of the posterior occipital condyle was required to gain access to the lateral aspect of the brain stem. The amount of occipital condyle resection varies by patient and pathology.
Outcome/Result
Maximal total resection of the tumor was achieved (
Fig. 1B, C
), and the patient was discharged on postoperative day 4 with no neurologic deficits. The technique for tumor microdissection (
Fig. 2
) is shown in the video.
Conclusion
Given the close proximity of foramen magnum meningiomas to vital structures at the craniocervical junction, surgical resection with careful microdissection and preservation of the overlying dura to prevent postoperative pseudomeningocele is necessary to successfully manage this pathology in those patients who are surgical candidates.
The link to the video can be found at:
https://youtu.be/Mds9N1x2zE0
.
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Affiliation(s)
- Robert T Wicks
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Xiaochun Zhao
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Celene B Mulholland
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
| | - Peter Nakaji
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States
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12
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Zhao X, Wicks RT, Belykh E, Przybylowski CJ, Labib MA, Nakaji P. Two cases of brainstem neurocysticercosis removal: operative video. Neurosurgical Focus: Video 2019; 1:V4. [PMID: 36284864 PMCID: PMC9541660 DOI: 10.3171/2019.10.focusvid.19458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/15/2019] [Indexed: 11/09/2022]
Abstract
Neurocysticercosis is primarily managed with anthelminthic, antiepileptic, and corticosteroid therapies. Surgical removal of the larval cyst is indicated when associated mass effect causes neurological symptoms, as demonstrated in two cases. Cyst resection was achieved via the far lateral approach for a cervicomedullary cyst in one patient and via the subtemporal approach for a mesencephalic cyst in another. The cyst wall should be kept intact, when possible, to avoid dissemination of the inflammation-evoking contents. As the contents are usually semisolid and can be removed via suction, it is not necessary to remove the gliotic capsule or adherent portions of the cyst wall in highly eloquent locations. The video can be found here: https://youtu.be/GqbaJu5sy1o.
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Affiliation(s)
- Xiaochun Zhao
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; and
| | - Robert T. Wicks
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; and
| | - Evgenii Belykh
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; and
- Irkutsk State Medical University, Irkutsk, Russia
| | - Colin J. Przybylowski
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; and
| | - Mohamed A. Labib
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; and
| | - Peter Nakaji
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona; and
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13
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Zhao X, Belykh E, Przybylowski CJ, Borba Moreira L, Gandhi S, Tayebi Meybodi A, Cavallo C, Valli D, Wicks RT, Nakaji P. Surgical treatment of falcotentorial meningiomas: a retrospective review of a single-institution experience. J Neurosurg 2019; 133:1-12. [PMID: 31374550 DOI: 10.3171/2019.4.jns19208] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/18/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Meningiomas at the falcotentorial junction represent a rare subgroup of complex meningiomas. Debate remains regarding the appropriate treatment strategy for and optimal surgical approach to these tumors, and surgical outcomes have not been well described in the literature. The authors reviewed their single-institution experience in the management, approach selection, and outcomes for patients with falcotentorial meningiomas. METHODS From the medical records, the authors identified all patients with falcotentorial meningiomas treated with resection at the Barrow Neurological Institute between January 2007 and October 2017. Perioperative clinical, surgical, and radiographic data were retrospectively collected. For patients who underwent the supracerebellar infratentorial approach, the tentorial angle was defined as the angle between the line joining the nasion with the tuberculum sellae and the tentorium in the midsagittal plane. RESULTS Falcotentorial meningiomas occurred in 0.97% (14/1441) of the patients with meningiomas. Most of the patients (13/14) were female, and the mean patient age was 59.8 ± 11.3 years. Of 17 total surgeries (20 procedures), 11 were single-stage primary surgeries, 3 were two-stage primary surgeries (6 procedures), 2 were reoperations for recurrence, and 1 was a reoperation after surgery had been aborted because of brain edema. Hydrocephalus was present in 5 of 17 cases, 4 of which required additional treatment. Various approaches were used, including the supracerebellar infratentorial (4/17), occipital transtentorial/transfalcine (4/17), anterior interhemispheric transsplenial (3/17), parietal transventricular (1/17), torcular (2/17), and staged supracerebellar infratentorial and occipital transtentorial/transfalcine (3/17) approaches. Of the 17 surgeries, 9 resulted in Simpson grade IV resection, and 3, 1, and 4 surgeries resulted in Simpson grades III, II, and I resection, respectively. The tentorial angle in cases with Simpson grade I resection was significantly smaller than in those with an unfavorable resection grade (43.3° ± 4.67° vs 54.0° ± 3.67°, p = 0.04). Complications occurred in 10 of 22 approaches (17 surgeries) and included visual field defects (6 cases, 2 permanent and 4 transient), hemiparesis (2 cases), hemidysesthesia (1 case), and cerebellar hematoma (1 case). CONCLUSIONS Falcotentorial meningiomas are challenging lesions. A steep tentorial angle is an unfavorable preoperative radiographic factor for achieving maximal resection with the supracerebellar infratentorial approach. Collectively, the study findings show that versatility is required to treat patients with falcotentorial meningiomas and that treatment goals and surgical approach must be individualized to obtain optimal surgical results.
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Affiliation(s)
- Xiaochun Zhao
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Evgenii Belykh
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
- 2Irkutsk State Medical University, Irkutsk, Russia
| | - Colin J Przybylowski
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Leandro Borba Moreira
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Sirin Gandhi
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Ali Tayebi Meybodi
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Claudio Cavallo
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Daniel Valli
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Robert T Wicks
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
| | - Peter Nakaji
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona; and
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14
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Nisson PL, Wicks RT, Zhao X, James WS, Xu D, Nakaji P. Insular cavernous malformation resection through a minipterional, transsylvian approach. Neurosurgical Focus: Video 2019; 1:V26. [PMID: 36285066 PMCID: PMC9541656 DOI: 10.3171/2019.7.focusvid.19148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/16/2019] [Indexed: 11/29/2022]
Abstract
Cavernous malformations of the brain are low-flow vascular lesions that have a propensity to hemorrhage. Extensive surgical approaches are often required for operative cure of deep-seated lesions. A 23-year-old female presented with a cavernous malformation of the left posterior insula with surrounding hematoma measuring up to 3 cm. A minimally invasive (mini-)pterional craniotomy with a transsylvian approach was selected. Endoscopic assistance was utilized to confirm complete resection of the lesion. The minipterional craniotomy is a minimally invasive approach that provides optimal exposure for sylvian fissure dissection and resection of many temporal and insular lesions. The video can be found here: https://youtu.be/9z6_EhU6lxs.
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Affiliation(s)
| | - Robert T. Wicks
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix; and
| | - Xiaochun Zhao
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix; and
| | | | - David Xu
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix; and
| | - Peter Nakaji
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix; and
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15
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Wicks RT, Zhao X, Hardesty DA, Liebelt BD, Nakaji P. Mini-pterional approach for clip ligation of ethmoidal dural arteriovenous fistula. Neurosurg Focus 2019; 46:V9. [PMID: 30939446 DOI: 10.3171/2019.2.focusvid.18660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/11/2019] [Indexed: 11/06/2022]
Abstract
Ethmoidal dural arteriovenous fistulas (DAVFs) have a near-universal association with cortical venous drainage and a malignant clinical course. Endovascular treatment options are often limited due to the high frequency of ophthalmic artery ethmoidal supply. A 64-year-old gentleman presented with syncope and was found to have a right ethmoidal DAVF. Rather than the traditional bicoronal craniotomy, an endoscope-assisted mini-pterional approach for clip ligation is demonstrated. The mini-pterional craniotomy allows a minimally invasive approach to ethmoidal DAVF via a lateral trajectory. The endoscope can help achieve full visualization in the narrow corridor.The video can be found here: https://youtu.be/ZroXp-T35DI.
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Affiliation(s)
- Robert T Wicks
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Xiaochun Zhao
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Douglas A Hardesty
- 2Department of Neurological Surgery, Wexner Medical Center, Ohio State University, Columbus, Ohio; and
| | - Brandon D Liebelt
- 3Department of Neurological Surgery, University of Vermont Medical Center, Burlington, Vermont
| | - Peter Nakaji
- 1Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona
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16
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Palma AE, Wicks RT, Popli G, Couture DE. Corpus callosotomy via laser interstitial thermal therapy: a case series. J Neurosurg Pediatr 2018; 23:303-307. [PMID: 30579267 DOI: 10.3171/2018.10.peds18368] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [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: 06/12/2018] [Accepted: 10/09/2018] [Indexed: 11/06/2022]
Abstract
Corpus callosotomy has been used as a form of surgical palliation for patients suffering from medically refractory generalized seizures, including drop attacks. Callosotomy has traditionally been described as involving a craniotomy with microdissection. MR-guided laser interstitial thermal therapy (MRg-LITT) has recently been used as a minimally invasive method for performing surgical ablation of epileptogenic foci and corpus callosotomy. The authors present 3 cases in which MRg-LITT was used to perform a corpus callosotomy as part of a staged surgical procedure for a patient with multiple seizure types and in instances when further ablation of residual corpus callosum is necessary after a prior open surgical procedure. To the authors' knowledge, this is the first case series of corpus callosotomy performed using the MRg-LITT system with a 3.3-year average follow-up. Although MRg-LITT is not expected to replace the traditional corpus callosotomy in all cases, it is a safe, effective, and durable alternative to the traditional open corpus callosotomy, particularly in the setting of a prior craniotomy.
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Affiliation(s)
| | | | - Gautam Popli
- 2Neurology, Wake Forest University School of Medicine, Winston-Salem, North Carolina
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17
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Nzou G, Wicks RT, Wicks EE, Seale SA, Sane CH, Chen A, Murphy SV, Jackson JD, Atala AJ. Human Cortex Spheroid with a Functional Blood Brain Barrier for High-Throughput Neurotoxicity Screening and Disease Modeling. Sci Rep 2018; 8:7413. [PMID: 29743549 PMCID: PMC5943588 DOI: 10.1038/s41598-018-25603-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 04/23/2018] [Indexed: 01/09/2023] Open
Abstract
The integral selectivity characteristic of the blood brain barrier (BBB) limits therapeutic options for many neurologic diseases and disorders. Currently, very little is known about the mechanisms that govern the dynamic nature of the BBB. Recent reports have focused on the development and application of human brain organoids developed from neuro-progenitor cells. While these models provide an excellent platform to study the effects of disease and genetic aberrances on brain development, they may not model the microvasculature and BBB of the adult human cortex. To date, most in vitro BBB models utilize endothelial cells, pericytes and astrocytes. We report a 3D spheroid model of the BBB comprising all major cell types, including neurons, microglia and oligodendrocytes, to recapitulate more closely normal human brain tissue. Spheroids show expression of tight junctions, adherens junctions, adherens junction-associated proteins and cell specific markers. Functional assessment using MPTP, MPP+ and mercury chloride indicate charge selectivity through the barrier. Junctional protein distribution was altered under hypoxic conditions. Our spheroid model may have potential applications in drug discovery, disease modeling, neurotoxicity and cytotoxicity testing.
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Affiliation(s)
- Goodwell Nzou
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA.
| | - R T Wicks
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
- Department of Neurological Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC, 27157, USA
| | - E E Wicks
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - S A Seale
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - C H Sane
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - A Chen
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - S V Murphy
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - J D Jackson
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
| | - A J Atala
- Wake Forest Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27101, USA
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18
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Hampson RE, Song D, Robinson BS, Fetterhoff D, Dakos AS, Roeder BM, She X, Wicks RT, Witcher MR, Couture DE, Laxton AW, Munger-Clary H, Popli G, Sollman MJ, Whitlow CT, Marmarelis VZ, Berger TW, Deadwyler SA. Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall. J Neural Eng 2018; 15:036014. [PMID: 29589592 DOI: 10.1088/1741-2552/aaaed7] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE We demonstrate here the first successful implementation in humans of a proof-of-concept system for restoring and improving memory function via facilitation of memory encoding using the patient's own hippocampal spatiotemporal neural codes for memory. Memory in humans is subject to disruption by drugs, disease and brain injury, yet previous attempts to restore or rescue memory function in humans typically involved only nonspecific, modulation of brain areas and neural systems related to memory retrieval. APPROACH We have constructed a model of processes by which the hippocampus encodes memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of short-term memory. A nonlinear multi-input, multi-output (MIMO) model of hippocampal CA3 and CA1 neural firing is computed that predicts activation patterns of CA1 neurons during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task. MAIN RESULTS MIMO model-derived electrical stimulation delivered to the same CA1 locations during the sample phase of DMS trials facilitated short-term/working memory by 37% during the task. Longer term memory retention was also tested in the same human subjects with a delayed recognition (DR) task that utilized images from the DMS task, along with images that were not from the task. Across the subjects, the stimulated trials exhibited significant improvement (35%) in both short-term and long-term retention of visual information. SIGNIFICANCE These results demonstrate the facilitation of memory encoding which is an important feature for the construction of an implantable neural prosthetic to improve human memory.
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Affiliation(s)
- Robert E Hampson
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States of America
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19
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Wicks RT, Jermakowicz WJ, Jagid JR, Couture DE, Willie JT, Laxton AW, Gross RE. Laser Interstitial Thermal Therapy for Mesial Temporal Lobe Epilepsy. Neurosurgery 2016; 79 Suppl 1:S83-S91. [DOI: 10.1227/neu.0000000000001439] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
Approximately one-third of patients with epilepsy do not achieve adequate seizure control through medical management alone. Mesial temporal lobe epilepsy (MTLE) is one of the most common forms of medically refractory epilepsy referred for surgical management. Stereotactic laser amygdalohippocampotomy using magnetic resonance-guided laser interstitial thermal therapy (MRg-LITT) is an important emerging therapy for MTLE. Initial published reports support MRg-LITT as a less invasive surgical option with a shorter hospital stay and fewer neurocognitive side effects compared with craniotomy for anterior temporal lobectomy with amygdalohippocampectomy and selective amygdalohippocampectomy. We provide a historical overview of laser interstitial thermal therapy development and the technological advancements that led to the currently available commercial systems. Current applications of MRg-LITT for MTLE, reported outcomes, and technical issues of the surgical procedure are reviewed. Although initial reports indicate that stereotactic laser amygdalohippocampotomy may be a safe and effective therapy for medically refractory MTLE, further research is required to establish its long-term effectiveness and its cost/benefit profile.
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Affiliation(s)
- Robert T. Wicks
- Department of Neurological Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | | | | | - Daniel E. Couture
- Department of Neurological Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Jon T. Willie
- Department of Neurosurgery, Emory University, Atlanta, Georgia
| | - Adrian W. Laxton
- Department of Neurological Surgery, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Robert E. Gross
- Department of Neurosurgery, Emory University, Atlanta, Georgia
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20
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Wicks RT, Bandarage D, Mott RT, Strowd RE, Laxton AW, Tatter SB, Chan MD, Lesser GJ. ACTR-56. UPFRONT CHEMORADIOTHERAPY IN GRADE 2 LOW GRADE GLIOMA, A SINGLE INSTITUTION EXPERIENCE. Neuro Oncol 2016. [DOI: 10.1093/neuonc/now212.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Goldstein ML, Wicks RT, Perri S, Sahraoui F. Kinetic scale turbulence and dissipation in the solar wind: key observational results and future outlook. Philos Trans A Math Phys Eng Sci 2015; 373:rsta.2014.0147. [PMID: 25848084 PMCID: PMC4394679 DOI: 10.1098/rsta.2014.0147] [Citation(s) in RCA: 5] [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] [Subscribe] [Scholar Register] [Accepted: 02/13/2015] [Indexed: 06/01/2023]
Abstract
Turbulence is ubiquitous in the solar wind. Turbulence causes kinetic and magnetic energy to cascade to small scales where they are eventually dissipated, adding heat to the plasma. The details of how this occurs are not well understood. This article reviews the evidence for turbulent dissipation and examines various diagnostics for identifying solar wind regions where dissipation is occurring. We also discuss how future missions will further enhance our understanding of the importance of turbulence to solar wind dynamics.
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Affiliation(s)
- M L Goldstein
- Code 672, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - R T Wicks
- Code 672, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA GPHI, Astronomy Department, University of Maryland, College Park, MD 20742, USA
| | - S Perri
- Dipartimento di Fisica, Università della Calabria, Rende 87036, Italy
| | - F Sahraoui
- Laboratoire de Physique des Plasmas, CNRS-UPMC, Ecole Polytechnique, Route de Saclay, Palaiseau 91128, France
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22
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Somasundaram A, Wicks RT, Lata AL, Qasem SA, Hsu W. En bloc spondylectomy for primary malignant fibrous histiocytoma of the thoracic spine with aortic involvement: case report. J Neurosurg Spine 2015; 22:399-405. [PMID: 25658464 DOI: 10.3171/2014.9.spine14155] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 11/06/2022]
Abstract
In this article, the authors describe a 48-year-old man who initially presented with progressively worsening back pain. Magnetic resonance imaging revealed a soft-tissue mass involving the T10-11 vertebral bodies with extension anteriorly into the aorta as well as epidural extension without spinal cord compression. A biopsy of the mass showed findings consistent with a malignant fibrous histiocytoma (MFH). A total en bloc spondylectomy with resection and reconstruction of the involved aorta using a vascular graft was performed. The patient received postoperative radiation therapy and is neurologically intact at 18 months postoperatively. To the authors' knowledge, this is the first reported case of a spinal MFH resection with aortic reconstruction.
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Weck PJ, Schaffner DA, Brown MR, Wicks RT. Permutation entropy and statistical complexity analysis of turbulence in laboratory plasmas and the solar wind. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 91:023101. [PMID: 25768612 DOI: 10.1103/physreve.91.023101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 06/04/2023]
Abstract
The Bandt-Pompe permutation entropy and the Jensen-Shannon statistical complexity are used to analyze fluctuating time series of three different turbulent plasmas: the magnetohydrodynamic (MHD) turbulence in the plasma wind tunnel of the Swarthmore Spheromak Experiment (SSX), drift-wave turbulence of ion saturation current fluctuations in the edge of the Large Plasma Device (LAPD), and fully developed turbulent magnetic fluctuations of the solar wind taken from the Wind spacecraft. The entropy and complexity values are presented as coordinates on the CH plane for comparison among the different plasma environments and other fluctuation models. The solar wind is found to have the highest permutation entropy and lowest statistical complexity of the three data sets analyzed. Both laboratory data sets have larger values of statistical complexity, suggesting that these systems have fewer degrees of freedom in their fluctuations, with SSX magnetic fluctuations having slightly less complexity than the LAPD edge I(sat). The CH plane coordinates are compared to the shape and distribution of a spectral decomposition of the wave forms. These results suggest that fully developed turbulence (solar wind) occupies the lower-right region of the CH plane, and that other plasma systems considered to be turbulent have less permutation entropy and more statistical complexity. This paper presents use of this statistical analysis tool on solar wind plasma, as well as on an MHD turbulent experimental plasma.
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Affiliation(s)
- P J Weck
- Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - D A Schaffner
- Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - M R Brown
- Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - R T Wicks
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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24
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Wicks RT, Azadi J, Mangraviti A, Zhang I, Hwang L, Joshi A, Bow H, Hutt-Cabezas M, Martin KL, Rudek MA, Zhao M, Brem H, Tyler BM. Local delivery of cancer-cell glycolytic inhibitors in high-grade glioma. Neuro Oncol 2014; 17:70-80. [PMID: 25053853 DOI: 10.1093/neuonc/nou143] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [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: 12/29/2022] Open
Abstract
BACKGROUND 3-bromopyruvate (3-BrPA) and dichloroacetate (DCA) are inhibitors of cancer-cell specific aerobic glycolysis. Their application in glioma is limited by 3-BrPA's inability to cross the blood-brain-barrier and DCA's dose-limiting toxicity. The safety and efficacy of intracranial delivery of these compounds were assessed. METHODS Cytotoxicity of 3-BrPA and DCA were analyzed in U87, 9L, and F98 glioma cell lines. 3-BrPA and DCA were incorporated into biodegradable pCPP:SA wafers, and the maximally tolerated dose was determined in F344 rats. Efficacies of the intracranial 3-BrPA wafer and DCA wafer were assessed in a rodent allograft model of high-grade glioma, both as a monotherapy and in combination with temozolomide (TMZ) and radiation therapy (XRT). RESULTS 3-BrPA and DCA were found to have similar IC50 values across the 3 glioma cell lines. 5% 3-BrPA wafer-treated animals had significantly increased survival compared with controls (P = .0027). The median survival of rats with the 50% DCA wafer increased significantly compared with both the oral DCA group (P = .050) and the controls (P = .02). Rats implanted on day 0 with a 5% 3-BrPA wafer in combination with TMZ had significantly increased survival over either therapy alone. No statistical difference in survival was noted when the wafers were added to the combination therapy of TMZ and XRT, but the 5% 3-BrPA wafer given on day 0 in combination with TMZ and XRT resulted in long-term survivorship of 30%. CONCLUSION Intracranial delivery of 3-BrPA and DCA polymer was safe and significantly increased survival in an animal model of glioma, a potential novel therapeutic approach. The combination of intracranial 3-BrPA and TMZ provided a synergistic effect.
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Affiliation(s)
- Robert T Wicks
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Javad Azadi
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Antonella Mangraviti
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Irma Zhang
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Lee Hwang
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Avadhut Joshi
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Hansen Bow
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Marianne Hutt-Cabezas
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Kristin L Martin
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Michelle A Rudek
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Ming Zhao
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Henry Brem
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
| | - Betty M Tyler
- Department of Neurosurgery (R.T.W., J.A., A.M., I.Z., L.H., A.J., H.B., M.H.-C., K.L.M., H.B., B.M.T.); Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland (H.B.); Division of Chemical Therapeutics, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, Maryland (M.A.R., M.Z.)
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Owens MJ, Horbury TS, Wicks RT, McGregor SL, Savani NP, Xiong M. Ensemble downscaling in coupled solar wind-magnetosphere modeling for space weather forecasting. Space Weather 2014; 12:395-405. [PMID: 26213518 PMCID: PMC4508929 DOI: 10.1002/2014sw001064] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/06/2014] [Indexed: 06/07/2023]
Abstract
UNLABELLED Advanced forecasting of space weather requires simulation of the whole Sun-to-Earth system, which necessitates driving magnetospheric models with the outputs from solar wind models. This presents a fundamental difficulty, as the magnetosphere is sensitive to both large-scale solar wind structures, which can be captured by solar wind models, and small-scale solar wind "noise," which is far below typical solar wind model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical "downscaling" of solar wind model results prior to their use as input to a magnetospheric model. As magnetospheric response can be highly nonlinear, this is preferable to downscaling the results of magnetospheric modeling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8 h filter, then add small-scale structure back in through the addition of random noise with the observed spectral characteristics. Here we use a very simple parameterization of noise based upon the observed probability distribution functions of solar wind parameters, but more sophisticated methods will be developed in the future. An ensemble of results from the simple downscaling scheme are tested using a model-independent method and shown to add value to the magnetospheric forecast, both improving the best estimate and quantifying the uncertainty. We suggest a number of features desirable in an operational solar wind downscaling scheme. KEY POINTS Solar wind models must be downscaled in order to drive magnetospheric models Ensemble downscaling is more effective than deterministic downscaling The magnetosphere responds nonlinearly to small-scale solar wind fluctuations.
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Affiliation(s)
- M J Owens
- Space Environment Physics Group, Department of Meteorology, University of Reading Reading, UK
| | - T S Horbury
- Space and Atmospheric Physics, Imperial College London London, UK
| | - R T Wicks
- NASA Goddard Space Flight Center Greenbelt, Maryland, USA ; Astronomy Department, University of Maryland College Park, Maryland, USA
| | - S L McGregor
- Department of Physics and Astronomy, Dartmouth College Hanover, New Hampshire, USA
| | - N P Savani
- NASA Goddard Space Flight Center Greenbelt, Maryland, USA ; School of Physics, Astronomy, Computational Sciences, George Mason University Fairfax, Virginia, USA
| | - M Xiong
- State Key Laboratory for SpaceWeather, Center for Space Science and Applied Research, Chinese Academy of Sciences Beijing, China
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26
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Wicks RT, Huang Y, Zhang K, Zhao M, Tyler BM, Suk I, Hwang L, Ruzevick J, Jallo G, Brem H, Pradilla G, Kang JU. Extravascular optical coherence tomography: evaluation of carotid atherosclerosis and pravastatin therapy. Stroke 2014; 45:1123-1130. [PMID: 24627118 DOI: 10.1161/strokeaha.113.002970] [Citation(s) in RCA: 7] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Extravascular optical coherence tomography (OCT), as a noninvasive imaging methodology with micrometer resolution, was evaluated in a murine model of carotid atherosclerosis by way of assessing the efficacy of pravastatin therapy. METHODS An OCT device was engineered for extravascular plaque imaging. Wild-type mice and apolipoprotein E-deficient (ApoE(-/-)) mice were randomized to 3 treatment groups: (1) wild-type on a diet of standard rodent chow (n=13); (2) ApoE(-/-) on a high-fat, atherosclerotic diet (HFD; n=13); and (3) ApoE(-/-) on a HFD given daily pravastatin (n=13). Mice were anesthetized and the left common carotid was surgically exposed. Three-dimensional (3D; 2 spatial dimensions+time) and 4D (3 spatial dimensions+time) OCT images of the vessel lumen patency were evaluated. After perfusion, in situ OCT imaging was performed for statistical comparison with the in vivo results and final histology. RESULTS Intraoperative OCT imaging positively identified carotid plaque in 100% of ApoE(-/-) mice on HFD. ApoE(-/-) mice on HFD had a significantly decreased lumen patency when compared with that in wild-type mice (P<0.001). Pravastatin therapy was found to increase lumen patency significantly in ApoE(-/-) mice on HFD (P<0.01; compared with ApoE(-/-) on HFD). The findings were confirmed with OCT imaging after perfusion and histology. CONCLUSIONS OCT imaging offers the potential for real-time, detailed vessel lumen evaluation, potentially improving surgical accuracy and outcomes during cerebrovascular neurosurgical procedures. Pravastatin significantly increases vessel lumen patency in the ApoE(-/-) mouse on HFD.
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Affiliation(s)
- Robert T Wicks
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yong Huang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Kang Zhang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Mingtao Zhao
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Betty M Tyler
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ian Suk
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Lee Hwang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jacob Ruzevick
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - George Jallo
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Henry Brem
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Departments of Oncology, Ophthalmology, and Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Gustavo Pradilla
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jin U Kang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland
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Pradilla G, Wicks RT, Hadelsberg U, Gailloud P, Coon AL, Huang J, Tamargo RJ. Accuracy of Computed Tomography Angiography in the Diagnosis of Intracranial Aneurysms. World Neurosurg 2013; 80:845-52. [DOI: 10.1016/j.wneu.2012.12.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 06/06/2012] [Accepted: 12/03/2012] [Indexed: 11/17/2022]
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28
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Grossman R, Brastianos H, Blakeley JO, Mangraviti A, Lal B, Zadnik P, Hwang L, Wicks RT, Goodwin RC, Brem H, Tyler B. Combination of anti-VEGF therapy and temozolomide in two experimental human glioma models. J Neurooncol 2013; 116:59-65. [PMID: 24185441 DOI: 10.1007/s11060-013-1268-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 10/09/2013] [Indexed: 12/24/2022]
Abstract
Anti-angiogenic agents, such as bevacizumab (BEV), can induce normalization of the blood brain barrier, which may influence the penetration and activity of a co-administered cytotoxic drug. However, it is unknown whether this effect is associated with a benefit in overall survival. This study employed intracranial human glioma models to evaluate the effect of BEV alone and in combination with temozolomide (TMZ) and/or radiation therapy (XRT) on overall survival. One hundred eight male athymic rats were intracranially injected with either U251 or U87 human glioma. Ten or eleven days after tumor inoculation, animals bearing U251 and U87, respectively, were treated with: TMZ alone (50 mg/kg for 5 consecutive days, P.O.), BEV alone (15 mg/kg, I.V.), a combination of TMZ and BEV, or a combination of TMZ, BEV, and a single fraction of XRT (20 Gy). Controls received no treatment. The U87 experiment was repeated and the relationship between survival and the extent of anti-angiogenesis via anti-laminin antibodies for the detection of blood vessels was assessed. In both U87 glioma experiments, all of the treatment groups had a statistically significant increase in survival as compared to the control groups. Also, for both U87 experiments the combination groups of TMZ and BEV had significantly better survival when compared to either treatment administered alone, with 75% of animals demonstrating long-term survival (LTS) (defined as animals alive 120 days after tumor implantation) in one experiment and 25% LTS in the repeat experiment. In the U251 glioma experiment, all treated groups (except BEV alone) had significantly improved survival as compared to controls with minimal statistical variance among groups. The percent vessel area was lowest in the group of animals treated with BEV alone. The addition of BEV to TMZ and/or XRT had variable effect on prolonging survival in the two human glioma models tested with reduced tumor vascularity in groups treated with BEV. These results indicate that BEV has anti-angiogenic activity and does not seem to hinder the effect of TMZ.
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Affiliation(s)
- Rachel Grossman
- Department of Neurosurgery, Johns Hopkins University School of Medicine, CRB II, Suite 2M45, 1550 Orleans Street, Baltimore, MD, 21231, USA
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Wicks RT, Mallet A, Horbury TS, Chen CHK, Schekochihin AA, Mitchell JJ. Alignment and scaling of large-scale fluctuations in the solar wind. Phys Rev Lett 2013; 110:025003. [PMID: 23383909 DOI: 10.1103/physrevlett.110.025003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/24/2012] [Indexed: 06/01/2023]
Abstract
We investigate the dependence of solar wind fluctuations measured by the Wind spacecraft on scale and on the degree of alignment between oppositely directed Elsasser fields. This alignment controls the strength of the nonlinear interactions and, therefore, the turbulence. We find that at scales larger than the outer scale of the turbulence the Elsasser fluctuations become on average more antialigned as the outer scale is approached from above. Conditioning structure functions using the alignment angle reveals turbulent scaling of unaligned fluctuations at scales previously believed to lie outside the turbulent cascade in the "1/f range." We argue that the 1/f range contains a mixture of a noninteracting antialigned population of Alfvén waves and magnetic force-free structures plus a subdominant population of unaligned cascading turbulent fluctuations.
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Affiliation(s)
- R T Wicks
- Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
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Masi BC, Tyler BM, Bow H, Wicks RT, Xue Y, Brem H, Langer R, Cima MJ. Intracranial MEMS based temozolomide delivery in a 9L rat gliosarcoma model. Biomaterials 2012; 33:5768-75. [PMID: 22591609 DOI: 10.1016/j.biomaterials.2012.04.048] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 04/21/2012] [Indexed: 10/28/2022]
Abstract
Primary malignant brain tumors (BT) are the most common and aggressive malignant brain tumor. Treatment of BTs is a daunting task with median survival just at 21 months. Methods of localized delivery have achieved success in treating BT by circumventing the blood brain barrier and achieving high concentrations of therapeutic within the tumor. The capabilities of localized delivery can be enhanced by utilizing mirco-electro-mechanical systems (MEMS) technology to deliver drugs with precise temporal control over release kinetics. An intracranial MEMS based device was developed to deliver the clinically utilized chemotherapeutic temozolomide (TMZ) in a rodent glioma model. The device is a liquid crystalline polymer reservoir, capped by a MEMS microchip. The microchip contains three nitride membranes that can be independently ruptured at any point during or after implantation. The kinetics of TMZ release were validated and quantified in vitro. The safety of implanting the device intracranially was confirmed with preliminary in vivo studies. The impact of TMZ release kinetics was investigated by conducting in vivo studies that compared the effects of drug release rates and timing on animal survival. TMZ delivered from the device was effective at prolonging animal survival in a 9L rodent glioma model. Immunohistological analysis confirmed that TMZ was released in a viable, cytotoxic form. The results from the in vivo efficacy studies indicate that early, rapid delivery of TMZ from the device results in the most prolonged animal survival. The ability to actively control the rate and timing of drug(s) release holds tremendous potential for the treatment of BTs and related diseases.
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Affiliation(s)
- Byron C Masi
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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31
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Wicks RT, Pradilla G, Raza SM, Hadelsberg U, Coon AL, Huang J, Tamargo RJ. Impact of Changes in Intraoperative Somatosensory Evoked Potentials on Stroke Rates After Clipping of Intracranial Aneurysms. Neurosurgery 2012; 70:1114-24; discussion 1124. [DOI: 10.1227/neu.0b013e31823f5cf7] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
Somatosensory evoked potential (SSEP) monitoring is used during intracranial aneurysm surgery to track the effects of anesthesia, surgical manipulation, and temporary clipping.
OBJECTIVE:
To present the outcomes of 663 consecutive patients (691 cases) treated surgically for intracranial aneurysms who underwent intraoperative SSEP monitoring and to analyze the sensitivity and specificity of significant SSEP changes in predicting postoperative stroke.
METHODS:
Of 691 surgeries analyzed, 403 (391 anterior circulation, 12 posterior circulation) were unruptured aneurysms and 288 (277 anterior, 11 posterior) were ruptured. Postoperatively, symptomatic patients underwent computed tomography imaging. Positive predictive value, negative predictive value, sensitivity, and specificity were calculated with a Fisher exact test (2-tailed P value).
RESULTS:
Changes in SSEP occurred in 45 of 691 cases (6.5%): 16 of 403 (4.0%) in unruptured aneurysms and 29 of 288 (10%) in ruptured aneurysms. In unruptured aneurysms, reversible SSEP changes were associated with a 20% stroke rate, but irreversible changes were associated with an 80% stroke rate. In ruptured aneurysms, however, reversible changes were associated with a 12% stroke rate, and irreversible changes were associated with a 42% stroke rate. The overall accuracy of SSEP changes in predicting postoperative stroke was as follows: positive predictive value, 30%; negative predictive value, 94%; sensitivity, 25%; and specificity, 95%.
CONCLUSION:
Intraoperative SSEP changes are more reliable in unruptured aneurysm cases than in ruptured cases. Whereas irreversible changes in unruptured cases were associated with an 80% stroke rate, such changes in ruptured cases did not have any adverse ischemic sequelae in 58% of patients. This information is helpful during the intraoperative assessment of reported SSEP changes.
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Affiliation(s)
- Robert T. Wicks
- The Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, Maryland
| | - Gustavo Pradilla
- The Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, Maryland
| | - Shaan M. Raza
- The Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, Maryland
| | - Uri Hadelsberg
- Technion-Israel Institute of Technology, Technion Faculty of Medicine, Haifa, Israel
| | - Alexander L. Coon
- The Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, Maryland
| | - Judy Huang
- The Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, Maryland
| | - Rafael J. Tamargo
- The Johns Hopkins University School of Medicine, Department of Neurosurgery, Baltimore, Maryland
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Abstract
The higher-order statistics of magnetic field magnitude fluctuations in the fast quiet solar wind are quantified systematically, scale by scale. We find a single global non-Gaussian scale-free behavior from minutes to over 5 h. This spans the signature of an inertial range of magnetohydrodynamic turbulence and a ~1/f range in magnetic field components. This global scaling in field magnitude fluctuations is an intrinsic component of the underlying texture of the solar wind and puts a strong constraint on any theory of solar corona and the heliosphere. Intriguingly, the magnetic field and velocity components show scale-dependent dynamic alignment outside of the inertial range.
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Affiliation(s)
- B Hnat
- Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, Coventry, United Kingdom
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Tyler B, Wadsworth S, Recinos V, Mehta V, Vellimana A, Li K, Rosenblatt J, Do H, Gallia GL, Siu IM, Wicks RT, Rudek MA, Zhao M, Brem H. Local delivery of rapamycin: a toxicity and efficacy study in an experimental malignant glioma model in rats. Neuro Oncol 2011; 13:700-9. [PMID: 21727209 DOI: 10.1093/neuonc/nor050] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Rapamycin, an anti-proliferative agent, is effective in the treatment of renal cell carcinoma and recurrent breast cancers. We proposed that this potent mammalian target of rapamycin inhibitor may be useful for the treatment of gliomas as well. We examined the cytotoxicity of rapamycin against a rodent glioma cell line, determined the toxicity of rapamycin when delivered intracranially, and investigated the efficacy of local delivery of rapamycin for the treatment of experimental malignant glioma in vivo. We also examined the dose-dependent efficacy of rapamycin and the effect when locally delivered rapamycin was combined with radiation therapy. Rapamycin was cytotoxic to 9L cells, causing 34% growth inhibition at a concentration of 0.01 µg/mL. No in vivo toxicity was observed when rapamycin was incorporated into biodegradable caprolactone-glycolide (35:65) polymer beads at 0.3%, 3%, and 30% loading doses and implanted intracranially. Three separate efficacy studies were performed to test the reproducibility of the effect of the rapamycin beads as well as the validity of this treatment approach. Animals treated with the highest dose of rapamycin beads tested (30%) consistently demonstrated significantly longer survival durations than the control and placebo groups. All dose-escalating rapamycin bead treatment groups (0.3%, 3% and 30%), treated both concurrently with tumor and in a delayed manner after tumor placement, experienced a significant increase in survival, compared with controls. Radiation therapy in addition to the simultaneous treatment with 30% rapamycin beads led to significantly longer survival duration than either therapy alone. These results suggest that the local delivery of rapamycin for the treatment of gliomas should be further investigated.
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Affiliation(s)
- Betty Tyler
- Department of Neurosurgery, Johns Hopkins Hospital, Baltimore, MD, USA.
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Wicks RT, Horbury TS, Chen CHK, Schekochihin AA. Anisotropy of imbalanced Alfvénic turbulence in fast solar wind. Phys Rev Lett 2011; 106:045001. [PMID: 21405329 DOI: 10.1103/physrevlett.106.045001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Indexed: 05/30/2023]
Abstract
We present the first measurement of the scale-dependent power anisotropy of Elsasser variables in imbalanced fast solar wind turbulence. The dominant Elsasser mode is isotropic at lower spacecraft frequencies but becomes increasingly anisotropic at higher frequencies. The subdominant mode is anisotropic throughout. There are two distinct subranges exhibiting different scalings within what is normally considered the inertial range. The low Alfvén ratio and the different scaling of the Elsasser modes suggests an interpretation of the observed discrepancy between the velocity and magnetic field scalings, the total energy is dominated by the latter. These results do not appear to be fully explained by any of the current theories of incompressible imbalanced MHD turbulence.
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Affiliation(s)
- R T Wicks
- Space and Atmospheric Physics Group, Imperial College London, London, United Kingdom.
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Chen CHK, Horbury TS, Schekochihin AA, Wicks RT, Alexandrova O, Mitchell J. Anisotropy of solar wind turbulence between ion and electron scales. Phys Rev Lett 2010; 104:255002. [PMID: 20867388 DOI: 10.1103/physrevlett.104.255002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Indexed: 05/29/2023]
Abstract
The anisotropy of turbulence in the fast solar wind, between the ion and electron gyroscales, is directly observed using a multispacecraft analysis technique. Second order structure functions are calculated at different angles to the local magnetic field, for magnetic fluctuations both perpendicular and parallel to the mean field. In both components, the structure function value at large angles to the field S{⊥} is greater than at small angles S{∥}: in the perpendicular component S{⊥}/S{∥}=5±1 and in the parallel component S{⊥}/S{∥}>3, implying spatially anisotropic fluctuations, k{⊥}>k{∥}. The spectral index of the perpendicular component is -2.6 at large angles and -3 at small angles, in broad agreement with critically balanced whistler and kinetic Alfvén wave predictions. For the parallel component, however, it is shallower than -1.9, which is considerably less steep than predicted for a kinetic Alfvén wave cascade.
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Affiliation(s)
- C H K Chen
- The Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom.
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Wicks RT, Chapman SC, Dendy RO. Mutual information as a tool for identifying phase transitions in dynamical complex systems with limited data. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 75:051125. [PMID: 17677040 DOI: 10.1103/physreve.75.051125] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Indexed: 05/16/2023]
Abstract
We use a well-known model [T. Vicsek, Phys. Rev. Lett. 15, 1226 (1995)] for flocking, to test mutual information as a tool for detecting order-disorder transitions, in particular when observations of the system are limited. We show that mutual information is a sensitive indicator of the phase transition location in terms of the natural dimensionless parameters of the system which we have identified. When only a few particles are tracked and when only a subset of the positional and velocity components is available, mutual information provides a better measure of the phase transition location than the susceptibility of the data.
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Affiliation(s)
- R T Wicks
- Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, UK
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Abstract
While previous research has sought to validate the chick separation stress paradigm as an anxiolytic screening assay, it is unknown whether the paradigm better models a nonspecific anxiety-like state or something similar to panic disorder or generalized anxiety disorder. To characterize the anxiety model pharmacologically, cockerels were administered drug probes that were either: (1) only effective for treating panic disorder (phenelzine 3.125-25.0 mg/kg), (2) effective for treating both panic disorder and generalized anxiety disorder (alprazolam 0.065-0.5 mg/kg; clonidine 0.1-0.25 mg/kg; imipramine 1.0-15.0 mg/kg), (3) only effective for treating generalized anxiety disorder (buspirone 2.5-10.0 mg/kg; trazodone 0.1-3.0 mg/kg) or (4) capable of exacerbating symptoms of panic disorder in humans (yohimbine 0.1-3.0 mg/kg). At 7 days after hatch, chicks received either vehicle or drug probe intramuscularly 15 min prior to social separation under a mirror (low-stress) or no-mirror (high-stress) condition for a 180-s observation period. Dependent measures were distress vocalizations to index separation stress and sleep-onset latency to index sedation. Phenelzine, alprazolam, imipramine and clonidine were able to attenuate distress vocalizations (at doses without significant sedation) whereas buspirone and trazodone did not. Paradoxically, yohimbine modestly attenuated distress vocalizations. These results suggest that the chick separation stress paradigm better models panic disorder than generalized anxiety disorder as an anxiolytic screen.
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Affiliation(s)
- Jason E Warnick
- Department of Psychology, University of Mississippi, Oxford, Mississippi 38677, USA
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