1
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Stacey A, Marks AJ, Naresh KN. Variant histology in nodular lymphocyte predominant Hodgkin lymphoma in an adult population: disease investigations and characteristics from a retrospective cohort. J Clin Pathol 2023; 76:137-140. [PMID: 35483890 DOI: 10.1136/jclinpath-2022-208190] [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: 02/16/2022] [Accepted: 04/21/2022] [Indexed: 01/24/2023]
Abstract
A subset of variant histological patterns of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) has been associated with advanced disease stage and increased recurrence risk. Histopathology reports on core needle (CNB) and/or surgical excision biopsies (SEB) for 33 adult patients with NLPHL were examined for variant histology prevalence and association with disease stage and clinical outcome. Variant histological pattern was present in 13/33 patients (39%). Obtained tissue was inadequate for diagnosis in 1/23 (4.3%) cases of CNB. Variant histology was associated with stage IV disease at presentation (p<0.001). While SEB should be the procedure of choice in workup of patients for a diagnosis of NLPHL, CNB is an alternate option when SEB is contraindicated or difficult to undertake. Diagnostic reports should specifically note presence of variant histological patterns. Although late-stage disease was associated with progression or recurrence, overall prognosis is excellent for patients with NLPHL.
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Affiliation(s)
- Arthur Stacey
- Faculty of Medicine, Imperial College London, London, UK
| | | | - Kikkeri N Naresh
- Histopathology, Imperial College London Centre for Haematology, London, UK.,Section of Pathology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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2
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Cubukcu M, Pöllath S, Tacchi S, Stacey A, Darwin E, Freeman CWF, Barton C, Hickey BJ, Marrows CH, Carlotti G, Back CH, Kazakova O. Manipulation of Magnetic Skyrmion Density in Continuous Ir/Co/Pt Multilayers. Micromachines (Basel) 2022; 13:1911. [PMID: 36363931 PMCID: PMC9693305 DOI: 10.3390/mi13111911] [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] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
We show that magnetic skyrmions can be stabilised at room temperature in continuous [Ir/Co/Pt]5 multilayers on SiO2/Si substrates without the prior application of electric current or magnetic field. While decreasing the Co thickness, a transition of the magnetic domain patterns from worm-like state to separated stripes is observed. The skyrmions are clearly imaged in both states using magnetic force microscopy. The density of skyrmions can be significantly enhanced after applying the "in-plane field procedure". Our results provide means to manipulate magnetic skyrmion density, further allowing for the optimised engineering of skyrmion-based devices.
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Affiliation(s)
- M. Cubukcu
- National Physical Laboratory, Teddington TW11 0LW, UK
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK
| | - S. Pöllath
- Institut für Experimentelle Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - S. Tacchi
- Istituto Officina dei Materiali del CNR (CNR-IOM), Sede Secondaria di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia, Italy
| | - A. Stacey
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - E. Darwin
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - C. W. F. Freeman
- National Physical Laboratory, Teddington TW11 0LW, UK
- London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH, UK
| | - C. Barton
- National Physical Laboratory, Teddington TW11 0LW, UK
| | - B. J. Hickey
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - C. H. Marrows
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
| | - G. Carlotti
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Pascoli, I-06123 Perugia, Italy
| | - C. H. Back
- Physik-Department, Technical University Munich, 85748 Garching, Germany
| | - O. Kazakova
- National Physical Laboratory, Teddington TW11 0LW, UK
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3
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Affiliation(s)
- Deepa J Arachchillage
- Department of haematology, Imperial College Healthcare NHS Trust, London, UK.,Department of Immunology and Inflammation, Imperial College London, London, UK.,Department of haematology, Royal Brompton Hospital, London, UK
| | - Arthur Stacey
- Department of Immunology and Inflammation, Imperial College London, London, UK
| | - Frances Akor
- Department of Pharmacology, Imperial College Healthcare NHS Trust, London, UK
| | - Martin Scotz
- Department of Intensive Care and Anaesthesia, Imperial College Healthcare NHS Trust, London, UK
| | - Mike Laffan
- Department of haematology, Imperial College Healthcare NHS Trust, London, UK.,Department of Immunology and Inflammation, Imperial College London, London, UK
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4
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Glen K, Stacey A, Thomas R. Understanding cell culture medium dynamics as a key stepping stone to optimistation of cell therapy bioprocessing. Cytotherapy 2020. [DOI: 10.1016/j.jcyt.2020.03.292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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5
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Thomas R, Glen K, Stacey A, Holland P, Shariatzadeh M. Efficient design of cell based product manufacturing using low data demand modelling approaches. Cytotherapy 2020. [DOI: 10.1016/j.jcyt.2020.03.333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Lang JE, Broadway DA, White GAL, Hall LT, Stacey A, Hollenberg LCL, Monteiro TS, Tetienne JP. Quantum Bath Control with Nuclear Spin State Selectivity via Pulse-Adjusted Dynamical Decoupling. Phys Rev Lett 2019; 123:210401. [PMID: 31809126 DOI: 10.1103/physrevlett.123.210401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Dynamical decoupling (DD) is a powerful method for controlling arbitrary open quantum systems. In quantum spin control, DD generally involves a sequence of timed spin flips (π rotations) arranged to either average out or selectively enhance coupling to the environment. Experimentally, errors in the spin flips are inevitably introduced, motivating efforts to optimize error-robust DD. Here we invert this paradigm: by introducing particular control "errors" in standard DD, namely, a small constant deviation from perfect π rotations (pulse adjustments), we show we obtain protocols that retain the advantages of DD while introducing the capabilities of quantum state readout and polarization transfer. We exploit this nuclear quantum state selectivity on an ensemble of nitrogen-vacancy centers in diamond to efficiently polarize the ^{13}C quantum bath. The underlying physical mechanism is generic and paves the way to systematic engineering of pulse-adjusted protocols with nuclear state selectivity for quantum control applications.
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Affiliation(s)
- J E Lang
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - D A Broadway
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - G A L White
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - L T Hall
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - A Stacey
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
- Melbourne Centre for Nanofabrication, Clayton, Victoria 3168, Australia
| | - L C L Hollenberg
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - T S Monteiro
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - J-P Tetienne
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
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7
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Broadway DA, Johnson BC, Barson MSJ, Lillie SE, Dontschuk N, McCloskey DJ, Tsai A, Teraji T, Simpson DA, Stacey A, McCallum JC, Bradby JE, Doherty MW, Hollenberg LCL, Tetienne JP. Microscopic Imaging of the Stress Tensor in Diamond Using in Situ Quantum Sensors. Nano Lett 2019; 19:4543-4550. [PMID: 31150580 DOI: 10.1021/acs.nanolett.9b01402] [Citation(s) in RCA: 5] [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] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The precise measurement of mechanical stress at the nanoscale is of fundamental and technological importance. In principle, all six independent variables of the stress tensor, which describe the direction and magnitude of compression/tension and shear stress in a solid, can be exploited to tune or enhance the properties of materials and devices. However, existing techniques to probe the local stress are generally incapable of measuring the entire stress tensor. Here, we make use of an ensemble of atomic-sized in situ strain sensors in diamond (nitrogen-vacancy defects) to achieve spatial mapping of the full stress tensor, with a submicrometer spatial resolution and a sensitivity of the order of 1 MPa (10 MPa) for the shear (axial) stress components. To illustrate the effectiveness and versatility of the technique, we apply it to a broad range of experimental situations, including mapping the stress induced by localized implantation damage, nanoindents, and scratches. In addition, we observe surprisingly large stress contributions from functional electronic devices fabricated on the diamond and also demonstrate sensitivity to deformations of materials in contact with the diamond. Our technique could enable in situ measurements of the mechanical response of diamond nanostructures under various stimuli, with potential applications in strain engineering for diamond-based quantum technologies and in nanomechanical sensing for on-chip mass spectroscopy.
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Affiliation(s)
- D A Broadway
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
- Centre for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - B C Johnson
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
- Centre for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - M S J Barson
- Laser Physics Centre, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - S E Lillie
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
- Centre for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - N Dontschuk
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
- Centre for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - D J McCloskey
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - A Tsai
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - T Teraji
- National Institute for Materials Science , Tsukuba , Ibaraki 305-0044 , Japan
| | - D A Simpson
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - A Stacey
- Centre for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
- Melbourne Centre for Nanofabrication , Clayton , VIC 3168 , Australia
| | - J C McCallum
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - J E Bradby
- Department Electronic Materials Engineering, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - M W Doherty
- Laser Physics Centre, Research School of Physics and Engineering , The Australian National University , Canberra , ACT 2601 , Australia
| | - L C L Hollenberg
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
- Centre for Quantum Computation and Communication Technology, School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
| | - J-P Tetienne
- School of Physics , University of Melbourne , Parkville , VIC 3010 , Australia
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Baker M, Muggridge R, Stacey A, Gribble K. Does standardised multichamber parenteral nutrition meet the needs of adult intestinal failure patients? Clin Nutr ESPEN 2019. [DOI: 10.1016/j.clnesp.2018.12.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Lee H, Stacey A, Klesert T, Wells C, Skalet A, Bloch C, Fung A, Bowen S, Wong T, Shibata D, Halasz L, Rengan R. A Contour-Based Approach for Predicting Corneal Toxicity in Patients with Uveal Melanoma Treated with Proton Therapy. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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10
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Haase JF, Vetter PJ, Unden T, Smirne A, Rosskopf J, Naydenov B, Stacey A, Jelezko F, Plenio MB, Huelga SF. Controllable Non-Markovianity for a Spin Qubit in Diamond. Phys Rev Lett 2018; 121:060401. [PMID: 30141651 DOI: 10.1103/physrevlett.121.060401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Indexed: 06/08/2023]
Abstract
We present a flexible scheme to realize non-Markovian dynamics of an electronic spin qubit, using a nitrogen-vacancy center in diamond where the inherent nitrogen spin serves as a regulator of the dynamics. By changing the population of the nitrogen spin, we show that we can smoothly tune the non-Markovianity of the electron spin's dynamics. Furthermore, we examine the decoherence dynamics induced by the spin bath to exclude other sources of non-Markovianity. The amount of collected measurement data is kept at a minimum by employing Bayesian data analysis. This allows for a precise quantification of the parameters involved in the description of the dynamics and a prediction of so far unobserved data points.
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Affiliation(s)
- J F Haase
- Institut für Theoretische Physik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - P J Vetter
- Institut für Quantenoptik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - T Unden
- Institut für Quantenoptik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - A Smirne
- Institut für Theoretische Physik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - J Rosskopf
- Institut für Theoretische Physik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - B Naydenov
- Institut für Quantenoptik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - A Stacey
- Element Six, Harwell Campus, Fermi Avenue, Didcot OX11 0QR, United Kingdom
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
| | - F Jelezko
- Institut für Quantenoptik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - M B Plenio
- Institut für Theoretische Physik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
| | - S F Huelga
- Institut für Theoretische Physik und IQST, Albert-Einstein-Allee 11, Universität Ulm, D-89069 Ulm, Germany
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11
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Affiliation(s)
- Arthur Stacey
- From the Department of Clinical Neuroscience, UCL Institute of Neurology, London, United Kingdom (A.S.); Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom (C.T.); and Clinical Neurosciences, UCL Great Ormond Street Institute of Child Health, London, United Kingdom (V.G.)
| | - Claire Toolis
- From the Department of Clinical Neuroscience, UCL Institute of Neurology, London, United Kingdom (A.S.); Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom (C.T.); and Clinical Neurosciences, UCL Great Ormond Street Institute of Child Health, London, United Kingdom (V.G.)
| | - Vijeya Ganesan
- From the Department of Clinical Neuroscience, UCL Institute of Neurology, London, United Kingdom (A.S.); Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom (C.T.); and Clinical Neurosciences, UCL Great Ormond Street Institute of Child Health, London, United Kingdom (V.G.)
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12
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Abstract
Seizures are common in neonates with moderate and severe hypoxic ischemic encephalopathy (HIE) and are associated with worse outcomes, independent of HIE severity. In contrast to adults and older children, no new drugs have been licensed for treatment of neonatal seizures over the last 50 years, because of a lack of controlled clinical trials. Hence, many antiseizure medications licensed in older children and adults are used off-label for neonatal seizure, which is associated with potential risks of adverse effects during a period when the brain is particularly vulnerable. Phenobarbital is worldwide the first-line drug and is considered standard of care, although there is a limited evidence base for its efficacy. Second-line agents include phenytoin, benzodiazepines, levetiracetam, and lidocaine. These drugs are discussed in more detail along with two emerging drugs (bumetanide and topiramate). More safety, pharmacokinetic, and efficacy data are needed from well-designed clinical trials to develop safe and effective antiseizure regimes for the treatment of neonatal seizures in HIE.
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Affiliation(s)
- Elissa Yozawitz
- Department of Neurology and Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Arthur Stacey
- UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Ronit M Pressler
- Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, Great Ormond Street, London, WC1N 3JH, UK. .,Clinical Neurosciences, UCL- Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
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13
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Glen K, Stacey A, Thomas R. Modelling productivity to optimise red blood cell manufacture from haematopoietic stem cells. Cytotherapy 2017. [DOI: 10.1016/j.jcyt.2017.02.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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Stacey A, Lucas S, Dikmen S, Temkin N, Bell KR, Brown A, Brunner R, Diaz-Arrastia R, Watanabe TK, Weintraub A, Hoffman JM. Natural History of Headache Five Years after Traumatic Brain Injury. J Neurotrauma 2017; 34:1558-1564. [PMID: 27927072 DOI: 10.1089/neu.2016.4721] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Headache is one of the most frequently reported symptoms following traumatic brain injury (TBI). Little is known about how these headaches change over time. We describe the natural history of headache in individuals with moderate to severe TBI over 5 years after injury. A total of 316 patients were prospectively enrolled and followed at 3, 6, 12, and 60 months after injury. Individuals were 72% male, 73% white, and 55% injured in motor vehicle crashes, with an average age of 42. Pre-injury headache was reported in 17% of individuals. New or worse headache prevalence remained consistent with at least 33% at all time points. Incidence was >17% at all time points with first report of new or worse headache in 20% of participants at 60 months. Disability related to headache was high, with average headache pain (on 0-10 scale) ranging from 5.5 at baseline to 5.7 at 60 months post-injury, and reports of substantial impact on daily life across all time points. More than half of classifiable headaches matched the profile of migraine or probable migraine. Headache is a substantial problem after TBI. Results suggest that ongoing assessment and treatment of headache after TBI is needed, as this symptom may be a problem up to 5 years post-injury.
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Affiliation(s)
- Arthur Stacey
- 1 Department of Rehabilitation Medicine, University of Washington Medical Center , Seattle, Washington
| | - Sylvia Lucas
- 1 Department of Rehabilitation Medicine, University of Washington Medical Center , Seattle, Washington.,2 Department of Neurology, University of Washington , Seattle, Washington.,3 Department of Neurological Surgery, University of Washington , Seattle, Washington
| | - Sureyya Dikmen
- 1 Department of Rehabilitation Medicine, University of Washington Medical Center , Seattle, Washington.,3 Department of Neurological Surgery, University of Washington , Seattle, Washington.,4 Department of Psychiatry and Behavioral Medicine, University of Washington , Seattle, Washington
| | - Nancy Temkin
- 1 Department of Rehabilitation Medicine, University of Washington Medical Center , Seattle, Washington.,3 Department of Neurological Surgery, University of Washington , Seattle, Washington.,5 Department of Biostatistics, University of Washington , Seattle, Washington
| | - Kathleen R Bell
- 6 Department of Physical Medicine and Rehabilitation, UT Southwestern , Dallas, Texas
| | - Allen Brown
- 7 Department of Physical Medicine and Rehabilitation, Mayo Clinic , Rochester, Minnesota
| | - Robert Brunner
- 8 Department of Physical Medicine and Rehabilitation, University of Alabama Birmingham , UAB Spain Rehabilitation Center, Birmingham, Alabama
| | - Ramon Diaz-Arrastia
- 9 Department of Neurology, University of Pennsylvania , Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Thomas K Watanabe
- 10 MossRehab at Elkins Park, Einstein Medical Center , Elkins Park, Pennsylvania
| | - Alan Weintraub
- 11 Craig Hospital , CNS Medical Group, Englewood, Colorado
| | - Jeanne M Hoffman
- 1 Department of Rehabilitation Medicine, University of Washington Medical Center , Seattle, Washington
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15
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Schenk AK, Sear MJ, Tadich A, Stacey A, Pakes CI. Oxidation of the silicon terminated (1 0 0) diamond surface. J Phys Condens Matter 2017; 29:025003. [PMID: 27841992 DOI: 10.1088/0953-8984/29/2/025003] [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] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The oxidation of the silicon terminated (1 0 0) diamond surface is investigated with a combination of high resolution photoelectron spectroscopy, low energy electron diffraction and near edge x-ray absorption fine structure spectroscopy. The effects of molecular [Formula: see text] and [Formula: see text] dosing under UHV conditions, as well as exposure to ambient conditions, have been explored. Our findings indicate that the choice of oxidant has little influence over the resulting surface chemistry, and we attribute approximately 85% of the surface oxygen to a peroxide-bridging arrangement. Additionally, oxidation does not alter the silicon-carbon bonding at the surface and therefore the [Formula: see text] reconstruction is still present.
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Affiliation(s)
- A K Schenk
- Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria 3086, Australia
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16
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Hoffman J, Lucas S, Stacey A, Temkin N, Dikmen S, Bell KR. Headache Five Years After Traumatic Brain Injuy. Arch Phys Med Rehabil 2016. [DOI: 10.1016/j.apmr.2016.08.226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Schenk AK, Rietwyk KJ, Tadich A, Stacey A, Ley L, Pakes CI. High resolution core level spectroscopy of hydrogen-terminated (1 0 0) diamond. J Phys Condens Matter 2016; 28:305001. [PMID: 27299369 DOI: 10.1088/0953-8984/28/30/305001] [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] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Synchrotron-based photoelectron spectroscopy experiments are presented that address a long standing inconsistency in the treatment of the C1s core level of hydrogen terminated (1 0 0) diamond. Through a comparison of surface and bulk sensitive measurements we show that there is a surface related core level component to lower binding energy of the bulk diamond component; this component has a chemical shift of [Formula: see text] eV which has been attributed to carbon atoms which are part of the hydrogen termination. Additionally, our results indicate that the asymmetry of the hydrogen terminated (1 0 0) diamond C1s core level is an intrinsic aspect of the bulk diamond peak which we have attributed to sub-surface carbon layers.
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Affiliation(s)
- A K Schenk
- Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria 3086, Australia
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18
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Schenk AK, Tadich A, Sear MJ, Qi D, Wee ATS, Stacey A, Pakes CI. The surface electronic structure of silicon terminated (100) diamond. Nanotechnology 2016; 27:275201. [PMID: 27211214 DOI: 10.1088/0957-4484/27/27/275201] [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] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A combination of synchrotron-based x-ray spectroscopy and contact potential difference measurements have been used to examine the electronic structure of the (3 × 1) silicon terminated (100) diamond surface under ultra high vacuum conditions. An occupied surface state which sits 1.75 eV below the valence band maximum has been identified, and indications of mid-gap unoccupied surface states have been found. Additionally, the pristine silicon terminated surface is shown to possess a negative electron affinity of -0.86 ± 0.1 eV.
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Affiliation(s)
- A K Schenk
- Department of Chemistry and Physics, La Trobe Institute for Molecular Sciences, La Trobe University, Victoria 3086, Australia
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Romach Y, Müller C, Unden T, Rogers LJ, Isoda T, Itoh KM, Markham M, Stacey A, Meijer J, Pezzagna S, Naydenov B, McGuinness LP, Bar-Gill N, Jelezko F. Spectroscopy of surface-induced noise using shallow spins in diamond. Phys Rev Lett 2015; 114:017601. [PMID: 25615501 DOI: 10.1103/physrevlett.114.017601] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Indexed: 06/04/2023]
Abstract
We report on the noise spectrum experienced by few nanometer deep nitrogen-vacancy centers in diamond as a function of depth, surface coating, magnetic field and temperature. Analysis reveals a double-Lorentzian noise spectrum consistent with a surface electronic spin bath in the low frequency regime, along with a faster noise source attributed to surface-modified phononic coupling. These results shed new light on the mechanisms responsible for surface noise affecting shallow spins at semiconductor interfaces, and suggests possible directions for further studies. We demonstrate dynamical decoupling from the surface noise, paving the way to applications ranging from nanoscale NMR to quantum networks.
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Affiliation(s)
- Y Romach
- The Racah Institute of Physics, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - C Müller
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology, University of Ulm, D-89081 Ulm, Germany
| | - T Unden
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology, University of Ulm, D-89081 Ulm, Germany
| | - L J Rogers
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology, University of Ulm, D-89081 Ulm, Germany
| | - T Isoda
- School of Fundamental Science and Technology, Keio University, Yokohama 223-8522 Japan
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama 223-8522 Japan
| | - M Markham
- Element Six, Ltd, Kings Ride Park, Ascot SL5 8BP, United Kingdom
| | - A Stacey
- Element Six, Ltd, Kings Ride Park, Ascot SL5 8BP, United Kingdom
| | - J Meijer
- Institute for Experimental Physics II, Linnéstraße 5, University of Leipzig, 04103 Leipzig, Germany
| | - S Pezzagna
- Institute for Experimental Physics II, Linnéstraße 5, University of Leipzig, 04103 Leipzig, Germany
| | - B Naydenov
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology, University of Ulm, D-89081 Ulm, Germany
| | - L P McGuinness
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology, University of Ulm, D-89081 Ulm, Germany
| | - N Bar-Gill
- The Racah Institute of Physics, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel and Department of Applied Physics, Rachel and Selim School of Engineering, Hebrew University, Jerusalem 91904, Israel
| | - F Jelezko
- Institute for Quantum Optics and Center for Integrated Quantum Science and Technology, University of Ulm, D-89081 Ulm, Germany
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20
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Müller C, Kong X, Cai JM, Melentijević K, Stacey A, Markham M, Twitchen D, Isoya J, Pezzagna S, Meijer J, Du JF, Plenio MB, Naydenov B, McGuinness LP, Jelezko F. Nuclear magnetic resonance spectroscopy with single spin sensitivity. Nat Commun 2014; 5:4703. [PMID: 25146503 PMCID: PMC4143926 DOI: 10.1038/ncomms5703] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 07/15/2014] [Indexed: 12/17/2022] Open
Abstract
Nuclear magnetic resonance spectroscopy and magnetic resonance imaging at the ultimate sensitivity limit of single molecules or single nuclear spins requires fundamentally new detection strategies. The strong coupling regime, when interaction between sensor and sample spins dominates all other interactions, is one such strategy. In this regime, classically forbidden detection of completely unpolarized nuclei is allowed, going beyond statistical fluctuations in magnetization. Here we realize strong coupling between an atomic (nitrogen-vacancy) sensor and sample nuclei to perform nuclear magnetic resonance on four (29)Si spins. We exploit the field gradient created by the diamond atomic sensor, in concert with compressed sensing, to realize imaging protocols, enabling individual nuclei to be located with Angstrom precision. The achieved signal-to-noise ratio under ambient conditions allows single nuclear spin sensitivity to be achieved within seconds.
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Affiliation(s)
- C Müller
- 1] Institute for Quantum Optics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany [2] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany [3]
| | - X Kong
- 1] Institute for Quantum Optics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany [2] Department of Modern Physics, Hefei National Laboratory for Physics Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China [3] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China [4]
| | - J-M Cai
- 1] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany [2] Institute for Theoretical Physics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany
| | - K Melentijević
- 1] Institute for Quantum Optics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany [2] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany
| | - A Stacey
- Element Six, Ltd., Ascot, Berkshire SL5 8BP, UK
| | - M Markham
- Element Six, Ltd., Ascot, Berkshire SL5 8BP, UK
| | - D Twitchen
- Element Six, Ltd., Ascot, Berkshire SL5 8BP, UK
| | - J Isoya
- Research Center for Knowledge Communities, University of Tsukuba, 1-2 Kasuga, Tsukuba, Ibaraki 305-8550, Japan
| | - S Pezzagna
- Experimental Physics II, University Leipzig, Linnéstr. 5, 03401 Leipzig, Germany
| | - J Meijer
- Experimental Physics II, University Leipzig, Linnéstr. 5, 03401 Leipzig, Germany
| | - J F Du
- 1] Department of Modern Physics, Hefei National Laboratory for Physics Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - M B Plenio
- 1] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany [2] Institute for Theoretical Physics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany
| | - B Naydenov
- 1] Institute for Quantum Optics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany [2] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany
| | - L P McGuinness
- 1] Institute for Quantum Optics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany [2] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany
| | - F Jelezko
- 1] Institute for Quantum Optics, Albert-Einstein Allee 11, University of Ulm, Ulm D-89081, Germany [2] Center for Integrated Quantum Science and Technology, University of Ulm, Ulm D-89081 Germany
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21
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Chu Y, de Leon NP, Shields BJ, Hausmann B, Evans R, Togan E, Burek MJ, Markham M, Stacey A, Zibrov AS, Yacoby A, Twitchen DJ, Loncar M, Park H, Maletinsky P, Lukin MD. Coherent optical transitions in implanted nitrogen vacancy centers. Nano Lett 2014; 14:1982-6. [PMID: 24588353 DOI: 10.1021/nl404836p] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We report the observation of stable optical transitions in nitrogen-vacancy (NV) centers created by ion implantation. Using a combination of high temperature annealing and subsequent surface treatment, we reproducibly create NV centers with zero-phonon lines (ZPL) exhibiting spectral diffusion that is close to the lifetime-limited optical line width. The residual spectral diffusion is further reduced by using resonant optical pumping to maintain the NV(-) charge state. This approach allows for placement of NV centers with excellent optical coherence in a well-defined device layer, which is a crucial step in the development of diamond-based devices for quantum optics, nanophotonics, and quantum information science.
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Affiliation(s)
- Y Chu
- Department of Physics, Harvard University , Cambridge, Massachusetts 02138, United States
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22
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Clark DJ, Catusse J, Stacey A, Borrow P, Gompels UA. Activation of CCR2+ human proinflammatory monocytes by human herpesvirus-6B chemokine N-terminal peptide. J Gen Virol 2013; 94:1624-1635. [PMID: 23535574 DOI: 10.1099/vir.0.050153-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Human monocytes expressing CCR2 with CD14 and CD16 can mediate antigen presentation, and promote inflammation, brain infiltration and immunosenescence. Recently identified roles are in human immunodeficiency virus infection, tuberculosis and parasitic disease. Human herpesvirus 6B (HHV-6B) encodes a chemokine, U83B, which is monospecific for CCR2, and is distinct from the related HHV-6A U83A, which activates CCR1, CCR4, CCR5, CCR6 and CCR8 on immune effector cells and dendritic cells. These differences could alter leukocyte-subset recruitment for latent/lytic replication and associated neuroinflammatory pathology. Therefore, cellular interactions between U83A and U83B could help dictate potential tropism differences between these viruses. U83A specificity is maintained in the 38-residue N-terminal spliced-truncated form. Here, we sought to determine the basis for the chemokine receptor specificity differences and identify possible applications. To do this we first analysed variation in a natural host population in sub-Saharan Africa where both viruses are equally prevalent and compared these to global strains. Analyses of U83 N-terminal variation in 112 HHV-6A and HHV-6B infections identified 6/38 U83A or U83B-specific residues. We also identified a unique single U83A-specific substitution in one U83B sequence, 'U83BA'. Next, the variation effects were tested by deriving N-terminal (NT) 17-mer peptides and assaying activation of ex vivo human leukocytes, the natural host and cellular target. Chemotaxis of CCR2+ leukocytes was potently induced by U83B-NT, but not U83BA-NT or U83A-NT. Analyses of the U83B-NT activated population identified migrated CCR2+, but not CCR5+, leukocytes. The U83BA-NT asparagine-lysine14 substitution disrupted activity, thus defining CCR2 specificity and acting as a main determinant for HHV-6A/B differences in cellular interactions. A flow-cytometry-based shape-change assay was designed, and used to provide further evidence that U83B-NT could activate CCR2+CD14+CD16+ monocytes. This defines a potential antiviral target for HHV-6A/B disease and novel peptide immunomodulator for proinflammatory monocytes.
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Affiliation(s)
- D J Clark
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, University of London, Keppel St., London WC1E 7HT, UK
| | - J Catusse
- University Clinic of Freiburg, Department of Hematology and Oncology, Freiburg, Germany.,Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, University of London, Keppel St., London WC1E 7HT, UK
| | - A Stacey
- Nuffield Department of Clinical Medicine, University of Oxford, UK
| | - P Borrow
- Nuffield Department of Clinical Medicine, University of Oxford, UK
| | - U A Gompels
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, University of London, Keppel St., London WC1E 7HT, UK
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23
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Acosta VM, Santori C, Faraon A, Huang Z, Fu KMC, Stacey A, Simpson DA, Ganesan K, Tomljenovic-Hanic S, Greentree AD, Prawer S, Beausoleil RG. Dynamic stabilization of the optical resonances of single nitrogen-vacancy centers in diamond. Phys Rev Lett 2012; 108:206401. [PMID: 23003160 DOI: 10.1103/physrevlett.108.206401] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Indexed: 06/01/2023]
Abstract
We report electrical tuning by the Stark effect of the excited-state structure of single nitrogen-vacancy (NV) centers located ≲100 nm from the diamond surface. The zero-phonon line (ZPL) emission frequency is controllably varied over a range of 300 GHz. Using high-resolution emission spectroscopy, we observe electrical tuning of the strengths of both cycling and spin-altering transitions. Under resonant excitation, we apply dynamic feedback to stabilize the ZPL frequency. The transition is locked over several minutes and drifts of the peak position on timescales ≳100 ms are reduced to a fraction of the single-scan linewidth, with standard deviation as low as 16 MHz (obtained for an NV in bulk, ultrapure diamond). These techniques should improve the entanglement success probability in quantum communications protocols.
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Affiliation(s)
- V M Acosta
- Hewlett-Packard Laboratories, 1501 Page Mill Road, Palo Alto, California 94304, USA.
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24
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Humphreys H, Coia J, Stacey A, Thomas M, Belli AM, Hoffman P, Jenks P, Mackintosh C. Guidelines on the facilities required for minor surgical procedures and minimal access interventions. J Hosp Infect 2012; 80:103-9. [DOI: 10.1016/j.jhin.2011.11.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 11/24/2011] [Indexed: 11/17/2022]
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25
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Virgincar N, Iyer S, Stacey A, Maharjan S, Pike R, Perry C, Wyeth J, Woodford N. Klebsiella pneumoniae producing KPC carbapenemase in a district general hospital in the UK. J Hosp Infect 2011; 78:293-6. [PMID: 21641083 DOI: 10.1016/j.jhin.2011.03.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 03/07/2011] [Indexed: 11/27/2022]
Abstract
We report two patients with multidrug-resistant KPC-carbapenemase-producing Klebsiella pneumoniae urinary tract infections. A bla(KPC-2) gene was detected in both of the isolates by polymerase chain reaction and sequencing. The isolates had identical pulsed-field gel electrophoresis patterns and belonged to sequence type ST11. The index patient probably acquired the KPC-producing strain while in hospital in Curaçao, with subsequent nosocomial transmission to the second patient occurring in our hospital. We describe the interventions that were taken to prevent its further spread within the acute Trust and the community.
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Affiliation(s)
- N Virgincar
- Royal Berkshire NHS Foundation Trust, Reading, UK.
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26
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McGuinness LP, Yan Y, Stacey A, Simpson DA, Hall LT, Maclaurin D, Prawer S, Mulvaney P, Wrachtrup J, Caruso F, Scholten RE, Hollenberg LCL. Quantum measurement and orientation tracking of fluorescent nanodiamonds inside living cells. Nat Nanotechnol 2011; 6:358-63. [PMID: 21552253 DOI: 10.1038/nnano.2011.64] [Citation(s) in RCA: 259] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/21/2011] [Indexed: 05/20/2023]
Abstract
Fluorescent particles are routinely used to probe biological processes. The quantum properties of single spins within fluorescent particles have been explored in the field of nanoscale magnetometry, but not yet in biological environments. Here, we demonstrate optically detected magnetic resonance of individual fluorescent nanodiamond nitrogen-vacancy centres inside living human HeLa cells, and measure their location, orientation, spin levels and spin coherence times with nanoscale precision. Quantum coherence was measured through Rabi and spin-echo sequences over long (>10 h) periods, and orientation was tracked with effective 1° angular precision over acquisition times of 89 ms. The quantum spin levels served as fingerprints, allowing individual centres with identical fluorescence to be identified and tracked simultaneously. Furthermore, monitoring decoherence rates in response to changes in the local environment may provide new information about intracellular processes. The experiments reported here demonstrate the viability of controlled single spin probes for nanomagnetometry in biological systems, opening up a host of new possibilities for quantum-based imaging in the life sciences.
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Affiliation(s)
- L P McGuinness
- School of Physics, University of Melbourne, Victoria 3010, Australia
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27
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Ganesan K, Stacey A, Meffin H, Lichter S, Greferath U, Fletcher EL, Prawer S. Diamond penetrating electrode array for epi-retinal prosthesis. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2010:6757-60. [PMID: 21095833 DOI: 10.1109/iembs.2010.5626003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper presents progress in the characterization and application of diamond penetrating electrode arrays for Epi-Retinal Prostheses. Electrical stimulation of degenerate retina has already been shown to restore partial vision for some blind patients, albeit at low spatial resolution. Higher resolution may be achievable by building arrays with electrodes that have greater areal density and closer proximity to target neurons. However, high standards of biocompatibility and hermeticity must be maintained, limiting the range of available materials of manufacture. Here, the design and histology of high density electrode arrays (approximately 100 electrodes/mm(2)) made from polycrystalline diamond and implanted into rat retinae are discussed. Results from initial steps in this process are reported.
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Affiliation(s)
- K Ganesan
- School of Physics, The University of Melbourne, Parkville, VIC 3010, Australia
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28
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Stacey A, Norris P, Dibben O, Qin L, Cohen M, Gay C, Denny T, Borrow P. OA011-04. Striking elevations in systemic and mucosal cytokine and chemokine levels in acute HIV-1 infection. Retrovirology 2009. [PMCID: PMC2767530 DOI: 10.1186/1742-4690-6-s3-o10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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29
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Qin L, Stacey A, Norris P, Wang P, Borrow P, Self SG. P10-14. Dynamic profiling and correlation analysis of plasma viral load and cytokine and chemokine profiles in acute HIV-1 infection. Retrovirology 2009. [PMCID: PMC2767632 DOI: 10.1186/1742-4690-6-s3-p145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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30
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Rabeau JR, Stacey A, Rabeau A, Prawer S, Jelezko F, Mirza I, Wrachtrup J. Single nitrogen vacancy centers in chemical vapor deposited diamond nanocrystals. Nano Lett 2007; 7:3433-7. [PMID: 17902725 DOI: 10.1021/nl0719271] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Nanodiamond crystals containing single color centers have been grown by chemical vapor deposition (CVD). The fluorescence from individual crystallites was directly correlated with crystallite size using a combined atomic force and scanning confocal fluorescence microscope. Under the conditions employed, the optimal size for single optically active nitrogen-vacancy (NV) center incorporation was measured to be 60-70 nm. The findings highlight a strong dependence of NV incorporation on crystal size, particularly with crystals less than 50 nm in size.
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Affiliation(s)
- J R Rabeau
- Department of Physics, Division of Information and Communication Science, Macquarie University, New South Wales 2109, Australia.
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31
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Smyth ETM, Humphreys H, Stacey A, Taylor EW, Hoffman P, Bannister G. Survey of operating theatre ventilation facilities for minimally invasive surgery in Great Britain and Northern Ireland: current practice and considerations for the future. J Hosp Infect 2005; 61:112-22. [PMID: 16240467 DOI: 10.1016/j.jhin.2005.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Increasing use of minimally invasive surgery (MIS) and other invasive procedures has raised the question of what ventilation facilities are appropriate for such procedures to prevent infection. The Hospital Infection Society (HIS) Working Party on Infection Control in Operating Theatres undertook a survey of practice in Great Britain and Northern Ireland on the ventilation facilities provided for a variety of MIS and other procedures. Five hundred and fifty questionnaires were forwarded to HIS members, and 186 (39%) replies were received. Fifty-eight percent were from district general hospitals (DGHs). Designated theatres for orthopaedic surgery (although not necessarily ultraclean ventilated theatres) were available in more than 80% of hospitals, with approximately 50% of hospitals having designated theatres for a variety of other surgical subspecialities. Approximately two-thirds of urological procedures were performed in conventionally ventilated operating theatres. Most radiological procedures were performed in non-ventilated theatres or treatment rooms. In around half of the DGHs and university/referral hospitals, orthopaedic MIS procedures such as arthroscopy were performed in ultraclean ventilated theatres. This survey revealed considerable variation in the use of conventionally ventilated theatres and ultraclean ventilated theatres. In particular, many radiological and anaesthetic procedures are performed in treatment rooms or ventilated rooms with less than 20 air changes per hour. Whilst it is not clear whether this is acceptable practice given current knowledge, large-scale clinical trials to determine what standards of ventilation are appropriate to minimize infection for these types of procedures would be difficult to conduct. Research is needed on the relative risk of airborne infection for a variety of procedures, including whether all prosthetic implant procedures should be carried out in ultraclean ventilated theatres, as infection associated with implants is often of airborne origin and of considerable clinical significance.
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Affiliation(s)
- E T M Smyth
- Department of Bacteriology, The Royal Hospitals, Belfast, Northern Ireland, UK
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32
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Abstract
As part of the preparation for the report of the Hospital Infection Society Working Party on Infection Control and Operating Theatres, studies published from the UK on the subject of operating theatre ventilation were reviewed. Few have convincingly demonstrated a direct relationship between the microbiological quality of operating theatre air and postoperative wound infection. Nevertheless, the findings from these studies have had a major influence on the development of official UK guidance on the design, performance and testing of ventilation in both conventional and ultraclean operating theatres.
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Affiliation(s)
- A Stacey
- Department of Microbiology, Royal Berkshire Hospital, Reading, UK.
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33
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Hoffman PN, Williams J, Stacey A, Bennett AM, Ridgway GL, Dobson C, Fraser I, Humphreys H. Microbiological commissioning and monitoring of operating theatre suites. J Hosp Infect 2002; 52:1-28. [PMID: 12372322 DOI: 10.1053/jhin.2002.1237] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- P N Hoffman
- Central Public Health Laboratory, London, UK.
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34
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Aiono S, Stacey A, Magee TR, Galland RB. The effect of intraoperative autotransfusion on antibiotic pharmacokinetics during elective abdominal aortic aneurysm repair. Cardiovasc Surg 2000; 8:137-40. [PMID: 10737350 DOI: 10.1016/s0967-2109(99)00099-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AIM Blood loss during aortic surgery has been reduced by the use of cell-salvage techniques (CS). Antibiotics are used routinely to prevent prosthetic graft infection. The influence of CS on antibiotic levels is unknown. This study measured antibiotic levels in serum and cell-salvage fluid during aortic reconstruction. METHODS Teicoplanin, a glycopeptide with activity against gram positive bacteria was the antibiotic studied. Serial blood levels were measured after a single intravenous dose (400 mg) in five patients undergoing elective aortic aneurysm repair. Patient ages ranged from 67 to 82 yr. Cell-salvage (Dideco compact A75171) fluid was also assayed. SETTING District General Hospital RESULTS Serum teicoplanin levels peaked at mean 67.8 mg/l (SD 8.9 mg/l) 5 min after administration, and fell to mean 2.88 mg/l (SD 0.4 mg/l) at 720 min. This is less than levels in healthy volunteers but above the MIC90 for most Gram positive bacterial pathogens encountered in aortic surgery. Teicoplanin levels in discarded CS fluid at the end of the procedure were 0.56 mg/l (SD 0.71 mg/l). CONCLUSIONS Teicoplanin blood levels are reduced during aortic surgery. Levels remain adequate for antibacterial prophylaxis for 12 h postoperatively other than for methicillin-resistant staphylococcus epidermidis (MRSE). Compared with patients undergoing arterial reconstruction without the use of a cell-salvage device there is no significant loss due to CS use.
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Affiliation(s)
- S Aiono
- Department of Surgery, Royal Berkshire Hospital, Reading, UK
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35
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Abstract
Participation in rugby football can expose individuals to a variety of infectious diseases both on and off the field of play. The close physical contact and trauma inherent in playing rugby facilitates the transmission of viral, bacterial and fungal pathogens between players and may also lead to the acquisition of potentially lethal infections from the environment, such as tetanus. In the past few years there have been a number of reported outbreaks of infection amongst rugby players in the medical literature. The appearance of HIV infection has focused attention on the potential for transmission of this and other blood-borne viruses such as hepatitis B and C viruses from bleeding wounds sustained on the rugby field. As a result, various expert bodies have produced guidelines on the management of players with bleeding wounds. Opportunities are now available to rugby players to play outside their own countries, including the third world. This can bring them into contact with a wide range of travel-associated infections, some of which may be life threatening. In view of the above it is clear that rugby players and those who coach and manage rugby teams require information and education on the subject of infection and its prevention, as well as access to appropriate medical care and expertise. Many of the infections seen in rugby players are preventable, e.g. by promoting hygienic facilities and conduct in changing rooms and on the field of play, by exclusion of infected players from contact with others and, in some cases, by immunisation or chemoprophylaxis. Players who present with infections should be assessed, correctly diagnosed (using laboratory investigations where appropriate) and treated, and measures should be taken to prevent spread to team-mates and other contacts while respecting the confidentiality of the individual. Any outbreaks of infection should be reported to the appropriate authorities. There is evidence to suggest that strenuous physical exercise such as playing rugby can make individuals susceptible to certain types of infection and prolong time to recovery. More information is required on the true frequency and effects of infection in rugby players.
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Affiliation(s)
- A Stacey
- Microbiology Department, Royal Berkshire and Battle Hospitals NHS Trust, Reading, England.
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36
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Abstract
Systemic infection caused by Arcanobacterium haemolyticum is uncommon. We report a case of empyema and bacteraemia caused by this organism concomitant with Mycoplasma pneumoniae infection.
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Affiliation(s)
- A Stacey
- Microbiology Department, Royal Berkshire Hospital, Reading, Berks., UK
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38
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Abstract
In 1958, Campbell observed that certain artificial pupil displacements could considerably change acuity (measured by viewing gratings) while others had very little effect. He sought an explanation of the small retinal contribution to those effects that was consistent with the Stiles-Crawford effect. This paper suggests an explanation that satisfies that requirement using a waveguide model of the retinal cones. We show that the waveguiding properties of the receptors make them sensitive to obliquely incident exciting waves and this provides some support for the hypothesis that both the Stiles-Crawford and Campbell effects are manifestations of the same underlying waveguide nature of the receptors.
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Affiliation(s)
- C Pask
- School of Mathematics and Statistics, University College, Australian Defence Force Academy, Canberra, ACT, Australia.
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39
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Abstract
OBJECTIVE To explore the usefulness of the critical incident technique in primary care to improve policy and practice to prevent cases of suicide. DESIGN Inviting all primary care teams in County Durham with a patient who committed suicide between 1 June 1993 and 31 May 1994 to take part in a critical incident audit with an external facilitator. RESULTS 49 cases of suicide were available for study, registered with 31 practices. 19 (61%) practices accounting for 27 (55%) cases agreed to take part. Case discussions showed areas where practice could be improved, but no substantive preventive measures were identified within primary care, which would reduce the number of people committing suicide. The wider social and economic context was thought to be more important. CONCLUSIONS The use of the critical incident technique in primary care may have only a limited role in improving the management of people at risk from suicide. However, one of the potential strengths of this approach is to encourage reflection on practice in a difficult emotional area.
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Affiliation(s)
- A Stacey
- European Collection of Cell Cultures, Centre for Applied Microbiology and Research, Salisbury, Wilts, UK
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41
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Abstract
We describe the case of a neonate with bacteraemia from whom the recently described organism Arcobacter butzleri was isolated. This appears to be the first report of the organism causing neonatal infection. Clinical details suggest that the infection was contracted in utero, although the mother showed no evidence of disease before delivery. Treatment of the preterm infant was ultimately successful in resolving the infection but the organism proved resistant to a wide range of antibiotics. Similar patterns of antibiotic resistance were also observed in 39 reference and field strains of the genus Arcobacter. These findings, combined with available data on the distribution of Arcobacter species, suggest that these organisms may be important human pathogens. Optimized methods for their isolation and identification are therefore required so as to ascertain their role in human disease.
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Affiliation(s)
- S L On
- Epidemiological Identification and Typing Unit, Central Public Health Laboratory, London, UK
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42
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Stacey A, Schnieke A, Kerr M, Scott A, McKee C, Cottingham I, Binas B, Wilde C, Colman A. Lactation is disrupted by alpha-lactalbumin deficiency and can be restored by human alpha-lactalbumin gene replacement in mice. Proc Natl Acad Sci U S A 1995; 92:2835-9. [PMID: 7708733 PMCID: PMC42313 DOI: 10.1073/pnas.92.7.2835] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mice carrying either a deletion of the murine alpha-lactalbumin (alpha-lac) gene (null allele) or its replacement by the human alpha-lac gene (humanized allele) have been generated by gene targeting. Homozygous null females are alpha-lac-deficient, produce reduced amounts of thickened milk containing little or no lactose, and cannot sustain their offspring. This provides definitive evidence that alpha-lac is required for lactose synthesis and that lactose is important for milk production. Females homozygous for the humanized allele lactate normally, indicating that human alpha-lac can replace murine alpha-lac. Mouse and human alpha-lac expression was compared in mice heterozygous for the humanized allele. The human gene expressed approximately 15-fold greater mRNA and approximately 14-fold greater protein than the mouse, indicating that the major determinants of human alpha-lac expression are close to, or within, the human gene and that the mouse locus does not exert a negative influence on alpha-lac expression. Variations in alpha-lac expression levels in nondeficient mice did not affect milk lactose concentration, but the volume of milk increased slightly in mice homozygous for the humanized allele. These variations demonstrated that alpha-lac expression in mice is gene dosage dependent.
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Affiliation(s)
- A Stacey
- PPL Therapeutics, Edinburgh, Scotland
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Stacey A, Pask C. Spatial-frequency response of a photoreceptor and its wavelength dependence. I. Coherent sources. J Opt Soc Am A Opt Image Sci Vis 1994; 11:1193-1198. [PMID: 8189282 DOI: 10.1364/josaa.11.001193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The response of an isolated model foveal cone to a coherent sinusoidal intensity source is explored with use of the methods of photoreceptor optics. The dielectric waveguide model of a foveal cone that was previously used to explain the Stiles-Crawford effect and its wavelength dependence [Vision Res. 13, 1115 (1973)] is applied to photoreceptor excitation by coherent gratings with variable spatial frequency and light wavelength. The results indicate that the photoreceptors themselves contribute to visual acuity through a wavelength-dependent response at each spatial frequency. In particular, the isolated photoreceptor has a characteristic low-pass spatial-frequency-filter effect for wavelengths between 410 and 654 nm (where two waveguide modes are carried) and a flat response for wavelengths greater than 654 nm (the single-mode region).
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Affiliation(s)
- A Stacey
- Department of Mathematics, Royal Melbourne Institute of Technology, Victoria, Australia
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Bowen RA, Reed ML, Schnieke A, Seidel GE, Stacey A, Thomas WK, Kajikawa O. Transgenic cattle resulting from biopsied embryos: expression of c-ski in a transgenic calf. Biol Reprod 1994; 50:664-8. [PMID: 8167238 DOI: 10.1095/biolreprod50.3.664] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Producing transgenic cattle by microinjection of DNA into pronuclei has been inefficient and costly, in large part because of the cost of maintaining numerous nontransgenic pregnancies to term. We designed a system for early identification of transgenic embryos in which biopsies of embryos were assayed by polymerase chain reaction for presence of the transgene before embryo transfer. A total of 2555 embryos were microinjected with one of two DNA constructs. Of the 533 embryos biopsied, 112 were judged to be potentially transgenic and were transferred nonsurgically to recipients, resulting in production of 29 putative transgenic fetuses. One fetus and one calf (7% of offspring) were subsequently shown to be definitively transgenic. The calf was transgenic for a chicken c-ski cDNA, and several months after birth developed dramatic muscular hypertrophy followed by muscle degeneration. This phenotype was associated with expression of high levels of mRNA from the transgene.
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Affiliation(s)
- R A Bowen
- Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins 80523
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45
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Stacey A, Schnieke A, McWhir J, Cooper J, Colman A, Melton DW. Use of double-replacement gene targeting to replace the murine alpha-lactalbumin gene with its human counterpart in embryonic stem cells and mice. Mol Cell Biol 1994; 14:1009-16. [PMID: 8289781 PMCID: PMC358456 DOI: 10.1128/mcb.14.2.1009-1016.1994] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The mouse alpha-lactalbumin gene has been replaced with the human gene by two consecutive rounds of gene targeting in hypoxanthine phosphoribosyltransferase (HPRT)-deficient feeder-independent murine embryonic stem (ES) cells. One mouse alpha-lactalbumin allele was first replaced by an HPRT minigene which was in turn replaced by human alpha-lactalbumin. The end result is a clean exchange of defined DNA fragments with no other DNA remaining at the target locus. Targeted ES cells at each stage remained capable of contributing efficiently to the germ line of chimeric animals. Double replacement using HPRT-deficient ES cells and the HPRT selection system is therefore a powerful and flexible method of targeting specific alterations to animal genes. A typical strategy for future use would be to generate a null mutation which could then be used to produce multiple second-step alterations at the same locus.
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Affiliation(s)
- A Stacey
- Pharmaceutical Proteins Ltd., Roslin, Midlothian, Scotland
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46
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Fenton SP, Lamande SR, Hannagan M, Stacey A, Jaenisch R, Bateman JF. Genomic sequence of mouse COL1A1 encoding the collagen propeptides. Biochim Biophys Acta 1993; 1216:469-74. [PMID: 8268229 DOI: 10.1016/0167-4781(93)90016-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The nucleotide sequences of the mouse pro alpha 1(I) gene regions coding for the N- and C-propeptides is reported. The exon-intron structure was highly homologous to human COL1A1 and the deduced amino acid sequences of the N- and C-propeptides showed 67% and 91% identity with the human sequence. This gene sequence information will allow the production of specific gene mutations by site-directed mutagenesis to study the structure and function of these important propeptide domains.
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Affiliation(s)
- S P Fenton
- Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Australia
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47
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48
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Lee ST, Lee S, Peters DP, Hoffman GG, Stacey A, Greenspan DS. Deletion of the pro-alpha 1(I) N-propeptide affects secretion of type I collagen in Chinese hamster lung cells but not in Mov-13 mouse cells. J Biol Chem 1992; 267:24126-33. [PMID: 1429742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We have introduced two mutations into a full-length human pro-alpha 1(I) cDNA that delete 114 amino acids or the entire 139 amino acids of the N-propeptide domain. Wild-type and mutated versions of the cDNA were introduced into cultured Chinese hamster lung (CHL) cells, which do not produce endogenous type I collagen, and into Mov-13 mouse cells, which produce endogenous pro-alpha 2(I) chains but not pro-alpha 1(I) chains. As judged by resistance to proteases, neither mutation impaired intracellular triple helical assembly of human alpha 1(I) homotrimers in CHL cells, or of chimeric type I collagen comprised of human alpha 1(I) and mouse alpha 2(I) chains in Mov-13 cells. Thus, the N-propeptide is not necessary for intracellular assembly of the main helical collagen domain of type I collagen. In CHL cells the rate of secretion of the mutant homotrimers was greatly reduced as compared to wild type homotrimers, and by immunofluorescence and immunoelectron microscopy, the mutant chains were shown to be accumulated in large vesicular expansions of the rough endoplasmic reticulum. When such cells were retransfected with cDNA encoding wild-type human alpha 2(I) chains, mutant alpha 1(I) chains were not rescued and heterotrimers containing the mutant chains were also retained in the intracellular vesicles. By contrast, deletion of the N-propeptide did not affect secretion of heterotrimers containing mutant chains from Mov-13 cells. Thus, an intact N-propeptide appears necessary for efficient secretion of type I collagen from some but not all cell types.
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Affiliation(s)
- S T Lee
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison 53706
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49
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Lee S, Lee S, Peters D, Hoffman G, Stacey A, Greenspan D. Deletion of the pro-alpha 1(I) N-propeptide affects secretion of type I collagen in Chinese hamster lung cells but not in Mov-13 mouse cells. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)35955-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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50
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Wu H, Byrne MH, Stacey A, Goldring MB, Birkhead JR, Jaenisch R, Krane SM. Generation of collagenase-resistant collagen by site-directed mutagenesis of murine pro alpha 1(I) collagen gene. Proc Natl Acad Sci U S A 1990; 87:5888-92. [PMID: 2165607 PMCID: PMC54434 DOI: 10.1073/pnas.87.15.5888] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Collagenase (matrix metalloproteinase 1) cleaves type I, II, and III collagen helices at a specific site between Gly-Ile or Gly-Leu bonds (residues 775 and 776, P1-P1'). To understand the mechanism of collagen processing, mutations around the cleavage site have been introduced into the cloned murine pro alpha 1(I) collagen (Col1a1) gene. These mutant constructs have been transfected into homozygous Mov13 fibroblasts that do not express the endogenous Col1a1 gene due to a retroviral insertion. Secreted triple-helical type I collagens containing substitutions of Pro for Ile (position 776) (P1') were not cleaved by human rheumatoid synovial collagenase, whereas those containing substitutions of Met for Ile (position 776) were cleaved. Type I collagens containing double substitutions of Pro for Gln-774 (P2) and Ala-777 (P2') were not cleaved regardless of whether they contained the wild-type residue Ile at position 776 or the substitution of Met for Ile at position 776. The wild-type alpha 2(I) chains derived from the endogenous Col1a2 gene were also resistant to enzyme digestion when they were complexed with the mutant alpha 1(I) chains, indicating that the presence of normal alpha 1(I) sequences is critical for cleavage of the alpha 2(I) chains in the type I heterotrimer.
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Affiliation(s)
- H Wu
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02142
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