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Mack PC, Keller-Evans RB, Li G, Lofgren KT, Schrock AB, Trabucco SE, Allen JM, Tolba K, Oxnard GR, Huang RSP. Real-World Clinical Performance of a DNA-Based Comprehensive Genomic Profiling Assay for Detecting Targetable Fusions in Nonsquamous NSCLC. Oncologist 2024:oyae028. [PMID: 38401173 DOI: 10.1093/oncolo/oyae028] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 01/23/2024] [Indexed: 02/26/2024] Open
Abstract
BACKGROUND Genomic fusions are potent oncogenic drivers across cancer types and many are targetable. We demonstrate the clinical performance of DNA-based comprehensive genomic profiling (CGP) for detecting targetable fusions. MATERIALS AND METHODS We analyzed targetable fusion genes in >450 000 tissue specimens profiled using DNA CGP (FoundationOne CDx, FoundationOne). Using a de-identified nationwide (US-based) non-small cell lung cancer (NSCLC) clinico-genomic database, we assessed outcomes in patients with nonsquamous NSCLC (NonSqNSCLC) who received matched therapy based on a fusion identified using DNA CGP. Lastly, we modeled the added value of RNA CGP for fusion detection in NonSqNSCLC. RESULTS We observed a broad diversity of fusion partners detected with DNA CGP in conjunction with targetable fusion genes (ALK, BRAF, FGFR2, FGFR3, NTRK1/2/3, RET, and ROS1). In NonSqNSCLC with oncogenic ALK, NTRK, RET, and ROS1 fusions detected by DNA CGP, patients treated with a matched tyrosine kinase inhibitor had better real-world progression-free survival than those receiving alternative treatment regimens and benefit was observed regardless of the results of orthogonal fusion testing. An estimated 1.3% of patients with NonSqNSCLC were predicted to have an oncogenic driver fusion identified by RNA, but not DNA CGP, according to a model that accounts for multiple real-world factors. CONCLUSION A well-designed DNA CGP assay is capable of robust fusion detection and these fusion calls are reliable for informing clinical decision-making. While DNA CGP detects most driver fusions, the clinical impact of fusion detection is substantial for individual patients and exhaustive efforts, inclusive of additional RNA-based testing, should be considered when an oncogenic driver is not clearly identified.
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Affiliation(s)
- Philip C Mack
- Center for Thoracic Oncology, Tisch Cancer Institute, Icahn School of Medicine, Mount Sinai, New York, NY, USA
| | | | - Gerald Li
- Foundation Medicine, Inc., Cambridge, MA, USA
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Kasi PM, Lee JK, Pasquina LW, Decker B, Vanden Borre P, Pavlick DC, Allen JM, Parachoniak C, Quintanilha JCF, Graf RP, Schrock AB, Oxnard GR, Lovly CM, Tukachinsky H, Subbiah V. Circulating Tumor DNA Enables Sensitive Detection of Actionable Gene Fusions and Rearrangements Across Cancer Types. Clin Cancer Res 2024; 30:836-848. [PMID: 38060240 PMCID: PMC10870120 DOI: 10.1158/1078-0432.ccr-23-2693] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/03/2023] [Accepted: 12/05/2023] [Indexed: 12/08/2023]
Abstract
PURPOSE Genomic rearrangements can generate potent oncogenic drivers or disrupt tumor suppressor genes. This study examines the landscape of fusions and rearrangements detected by liquid biopsy (LBx) of circulating tumor DNA (ctDNA) across different cancer types. EXPERIMENTAL DESIGN LBx from 53,842 patients with 66 solid tumor types were profiled using FoundationOneLiquid CDx, a hybrid-capture sequencing platform that queries 324 cancer-related genes. Tissue biopsies (TBx) profiled using FoundationOneCDx were used as a comparator. RESULTS Among all LBx, 7,377 (14%) had ≥1 pathogenic rearrangement detected. A total of 3,648 (6.8%) LBx had ≥1 gain-of-function (GOF) oncogene rearrangement, and 4,428 (8.2%) LBx had ≥1 loss-of-function rearrangement detected. Cancer types with higher prevalence of GOF rearrangements included those with canonical fusion drivers: prostate cancer (19%), cholangiocarcinoma (6.4%), bladder (5.5%), and non-small cell lung cancer (4.4%). Although the prevalence of driver rearrangements was lower in LBx than TBx overall, the frequency of detection was comparable in LBx with a tumor fraction (TF) ≥1%. Rearrangements in FGFR2, BRAF, RET, and ALK, were detected across cancer types, but tended to be clonal variants in some cancer types and potential acquired resistance variants in others. CONCLUSIONS In contrast to some prior literature, this study reports detection of a wide variety of rearrangements in ctDNA. The prevalence of driver rearrangements in tissue and LBx was comparable when TF ≥1%. LBx presents a viable alternative when TBx is not available, and there may be less value in confirmatory testing when TF is sufficient.
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Affiliation(s)
- Pashtoon M. Kasi
- Weill Cornell Medicine, Englander Institute of Precision Medicine, New York Presbyterian Hospital, New York, New York
| | | | | | | | | | | | | | | | | | - Ryon P. Graf
- Foundation Medicine, Inc., Cambridge, Massachusetts
| | | | | | | | | | - Vivek Subbiah
- The University of Texas MD Anderson Cancer Center, Houston, Texas
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3
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Ware J, Boughton CK, Allen JM, Wilinska ME, Tauschmann M, Denvir L, Thankamony A, Campbell FM, Wadwa RP, Buckingham BA, Davis N, DiMeglio LA, Mauras N, Besser REJ, Ghatak A, Weinzimer SA, Hood KK, Fox DS, Kanapka L, Kollman C, Sibayan J, Beck RW, Hovorka R, Hovorka R, Acerini CL, Thankamony A, Allen JM, Boughton CK, Dovc K, Dunger DB, Ware J, Musolino G, Tauschmann M, Wilinska ME, Hayes JF, Hartnell S, Slegtenhorst S, Ruan Y, Haydock M, Mangat J, Denvir L, Kanthagnany SK, Law J, Randell T, Sachdev P, Saxton M, Coupe A, Stafford S, Ball A, Keeton R, Cresswell R, Crate L, Cripps H, Fazackerley H, Looby L, Navarra H, Saddington C, Smith V, Verhoeven V, Bratt S, Khan N, Moyes L, Sandhu K, West C, Wadwa RP, Alonso G, Forlenza G, Slover R, Towers L, Berget C, Coakley A, Escobar E, Jost E, Lange S, Messer L, Thivener K, Campbell FM, Yong J, Metcalfe E, Allen M, Ambler S, Waheed S, Exall J, Tulip J, Buckingham BA, Ekhlaspour L, Maahs D, Norlander L, Jacobson T, Twon M, Weir C, Leverenz B, Keller J, Davis N, Kumaran A, Trevelyan N, Dewar H, Price G, Crouch G, Ensom R, Haskell L, Lueddeke LM, Mauras N, Benson M, Bird K, Englert K, Permuy J, Ponthieux K, Marrero-Hernandez J, DiMeglio LA, Ismail H, Jolivette H, Sanchez J, Woerner S, Kirchner M, Mullen M, Tebbe M, Besser REJ, Basu S, London R, Makaya T, Ryan F, Megson C, Bowen-Morris J, Haest J, Law R, Stamford I, Ghatak A, Deakin M, Phelan K, Thornborough K, Shakeshaft J, Weinzimer SA, Cengiz E, Sherr JL, Van Name M, Weyman K, Carria L, Steffen A, Zgorski M, Sibayan J, Beck RW, Borgman S, Davis J, Rusnak J, Hellman A, Cheng P, Kanapka L, Kollman C, McCarthy C, Chalasani S, Hood KK, Hanes S, Viana J, Lanning M, Fox DS, Arreaza-Rubin G, Eggerman T, Green N, Janicek R, Gabrielson D, Belle SH, Castle J, Green J, Legault L, Willi SM, Wysham C. Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial. Lancet Digit Health 2022; 4:e245-e255. [PMID: 35272971 DOI: 10.1016/s2589-7500(22)00020-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 12/10/2021] [Accepted: 01/25/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population. METHODS In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299. FINDINGS Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis. INTERPRETATION The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX. FUNDING National Institute of Diabetes and Digestive and Kidney Diseases.
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Lawton J, Kimbell B, Rankin D, Ashcroft NL, Varghese L, Allen JM, Boughton CK, Campbell F, Randell T, Besser REJ, Trevelyan N, Hovorka R. Health professionals' views about who would benefit from using a closed-loop system: a qualitative study. Diabet Med 2020; 37:1030-1037. [PMID: 31989684 DOI: 10.1111/dme.14252] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/23/2020] [Indexed: 12/19/2022]
Abstract
AIM To explore health professionals' views about who would benefit from using a closed-loop system and who should be prioritized for access to the technology in routine clinical care. METHODS Health professionals (n = 22) delivering the Closed Loop from Onset in type 1 Diabetes (CLOuD) trial were interviewed after they had ≥ 6 months' experience supporting participants using a closed-loop system. Data were analysed thematically. RESULTS Interviewees described holding strong assumptions about the types of people who would use the technology effectively prior to the trial. Interviewees described changing their views as a result of observing individuals engaging with the closed-loop system in ways they had not anticipated. This included educated, technologically competent individuals who over-interacted with the system in ways which could compromise glycaemic control. Other individuals, who health professionals assumed would struggle to understand and use the technology, were reported to have benefitted from it because they stood back and allowed the system to operate without interference. Interviewees concluded that individual, family and psychological attributes cannot be used as pre-selection criteria and, ideally, all individuals should be given the chance to try the technology. However, it was recognized that clinical guidelines will be needed to inform difficult decisions about treatment allocation (and withdrawal), with young children and infants being considered priority groups. CONCLUSIONS To ensure fair and equitable access to closed-loop systems, prejudicial assumptions held by health professionals may need to be addressed. To support their decision-making, clinical guidelines need to be made available in a timely manner.
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Affiliation(s)
- J Lawton
- Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | - B Kimbell
- Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | - D Rankin
- Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, UK
| | - N L Ashcroft
- Wellcome Trust - Medical Research Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - L Varghese
- Cambridge Clinical Trials Unit, Cambridge, UK
| | - J M Allen
- Wellcome Trust - Medical Research Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- Department of Paediatrics, University of Cambridge, Cambridge, UK
| | - C K Boughton
- Wellcome Trust - Medical Research Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | | | - T Randell
- Nottingham Children's Hospital, Nottingham, UK
| | - R E J Besser
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Paediatrics, University of Oxford, Oxford, UK
| | - N Trevelyan
- Southampton Children's Hospital, Southampton, UK
| | - R Hovorka
- Wellcome Trust - Medical Research Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- Department of Paediatrics, University of Cambridge, Cambridge, UK
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5
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Schrock AB, Madison R, Rosenzweig M, Allen JM, Erlich RL, Wang SY, Chidiac T, Reddy VS, Riess JW, Yassa AE, Shakir A, Miller VA, Alexander BM, Venstrom J, McGregor K, Ali SM. Patients with NSCLCs Harboring Internal Inversions or Deletion Rearrangements of the ALK Gene Have Durable Responses to ALK Kinase Inhibitors. Lung Cancer (Auckl) 2020; 11:33-39. [PMID: 32368168 PMCID: PMC7184117 DOI: 10.2147/lctt.s239675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/24/2020] [Indexed: 12/24/2022]
Abstract
Background ALK fusions are targetable drivers in non-small-cell lung cancer (NSCLC). However, patients with NSCLC harboring ALK rearrangements without a fusion partner identified in DNA have also been shown to respond to ALK inhibitors. We aimed to characterize complex ALK variants that may predict sensitivity to multiple approved ALK inhibitors. Methods Comprehensive genomic profiling (CGP) of DNA isolated from formalin-fixed paraffin-embedded (FFPE) tumor tissue or blood-based circulating tumor DNA was performed for 39,159 NSCLC patients during routine clinical care. For a subset of cases, RNA sequencing was performed, and prior ALK test results and clinical treatment information were collected from treating physicians. Results We queried the Foundation Medicine NSCLC database and identified ALK internal inversions, as well as internal deletions, as the sole ALK rearrangements in 6 (0.02%) and 3 (0.01%) of cases, respectively. In cases with ALK internal inversions, RNA testing identified an EML4-ALK fusion in 2/2 cases evaluated, and 3/3 patients treated with ALK inhibitors had durable responses. A single patient with an ALK internal deletion and clinical data available responded to multiple ALK inhibitors. RNA data available for a subset of non-NSCLC cases suggest that ALK internal deletions removing a portion of the N-terminus are drivers themselves and do not result in ALK fusions. Fluorescence in situ hybridization (FISH) results were inconsistent for both classes of DNA events. Conclusion Rare internal inversions of ALK appear to be indicative of ALK fusions, which can be detected in RNA, and response to ALK inhibitors in patients with NSCLC. In contrast, ALK internal deletions are not associated with ALK fusions in RNA but likely represent targetable drivers themselves. These data suggest that CGP of DNA should be supplemented with immunohistochemistry or RNA-based testing to further resolve these events and match patients to effective therapies.
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Affiliation(s)
- Alexa B Schrock
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
| | - Russell Madison
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
| | - Mark Rosenzweig
- Foundation Medicine, Department of Translational Oncology and Clinical Reporting, Cambridge, MA, USA
| | - Justin M Allen
- Foundation Medicine, Department of Translational Oncology and Clinical Reporting, Cambridge, MA, USA
| | - Rachel L Erlich
- Foundation Medicine, Department of Translational Oncology and Clinical Reporting, Cambridge, MA, USA
| | - Siao-Yi Wang
- Loyola University Medical Cancer, Department of Hematology and Oncology, Maywood, IL, USA
| | - Tarek Chidiac
- Zangmeister Cancer Center, Department of Hematology and Oncology, Columbus, OH, USA
| | - Vodur Suresh Reddy
- Cancer Care Specialists, Department of Hematology and Oncology, Reno, NV, USA
| | - Jonathan W Riess
- UC Davis Comprehensive Cancer Center, Department of Hematology and Oncology Sacramento, CA, USA
| | - Ahmet Ersin Yassa
- UC Davis Comprehensive Cancer Center, Department of Hematology and Oncology Sacramento, CA, USA
| | - Abdur Shakir
- Sarah Bush Lincoln Health System, Department of Medical Oncology, Mattoon, IL, USA
| | - Vincent A Miller
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
| | - Brian M Alexander
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
| | - Jeffrey Venstrom
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
| | - Kimberly McGregor
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
| | - Siraj M Ali
- Foundation Medicine, Department of Clinical Development, Cambridge, MA, USA
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6
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Affiliation(s)
- C K Boughton
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
- Cambridge University Hospitals NHS Foundation Trust, Wolfson Diabetes and Endocrine Clinic, Cambridge, UK
| | - S Hartnell
- Cambridge University Hospitals NHS Foundation Trust, Wolfson Diabetes and Endocrine Clinic, Cambridge, UK
| | - J M Allen
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - R Hovorka
- Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
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7
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Lin DI, Allen JM, Hecht JL, Killian JK, Ngo NT, Edgerly C, Severson EA, Ali SM, Erlich RL, Ramkissoon SH, Vergilio JA, Ross JS, Elvin JA. SMARCA4 inactivation defines a subset of undifferentiated uterine sarcomas with rhabdoid and small cell features and germline mutation association. Mod Pathol 2019; 32:1675-1687. [PMID: 31190001 DOI: 10.1038/s41379-019-0303-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/14/2019] [Accepted: 05/15/2019] [Indexed: 12/28/2022]
Abstract
A rare subset of aggressive SMARCA4-deficient uterine sarcomas has been recently proposed, with only a limited number of cases having been previously described. Here, we identify 16 additional cases of SMARCA4-deficient uterine sarcoma from the database of a large, CLIA-certified and CAP-accredited, reference molecular laboratory, and we expand on their clinicopathological and genomic features. Median patient's age was 49 years (range 32-70). Most tumors were aggressive with distant metastasis. SMARCA4-deficient uterine sarcoma demonstrated predominantly rhabdoid or large epithelioid cells with abundant cytoplasm, but also had varying degrees of small cell and spindle cell morphology. Tumors were microsatellite stable and exhibited no other or only few co-occurring genomic alterations by comprehensive genomic profiling. We discovered one patient, who developed SMARCA4-deficient uterine sarcoma at the age of 55, had a germline SMARCA4 mutation, whose daughter had previously died of small cell carcinoma of the ovary, hypercalcemic type, at the age of 32. Our data support the notion that SMARCA4 inactivation is the driver oncogenic event of a morphologically and molecularly distinct form of uterine sarcoma. Identification of SMARCA4-deficient uterine sarcomas may be clinically important due to their aggressive behavior, germline association, and emerging targeted therapies.
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Affiliation(s)
- Douglas I Lin
- Foundation Medicine Inc., Cambridge, Massachusetts, USA.
| | | | | | | | - Nhu T Ngo
- Foundation Medicine Inc., Cambridge, Massachusetts, USA
| | | | | | - Siraj M Ali
- Foundation Medicine Inc., Cambridge, Massachusetts, USA
| | | | - Shakti H Ramkissoon
- Foundation Medicine, Morrisville, NC, USA.,Wake Forest Comprehensive Cancer Center and Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | | | - Jeffrey S Ross
- Foundation Medicine Inc., Cambridge, Massachusetts, USA.,Upstate Medical University, Syracuse, NY, USA
| | - Julia A Elvin
- Foundation Medicine Inc., Cambridge, Massachusetts, USA
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Hall MR, Bardayan DW, Baugher T, Lepailleur A, Pain SD, Ratkiewicz A, Ahn S, Allen JM, Anderson JT, Ayangeakaa AD, Blackmon JC, Burcher S, Carpenter MP, Cha SM, Chae KY, Chipps KA, Cizewski JA, Febbraro M, Hall O, Hu J, Jiang CL, Jones KL, Lee EJ, O'Malley PD, Ota S, Rasco BC, Santiago-Gonzalez D, Seweryniak D, Sims H, Smith K, Tan WP, Thompson P, Thornsberry C, Varner RL, Walter D, Wilson GL, Zhu S. Key ^{19}Ne States Identified Affecting γ-Ray Emission from ^{18}F in Novae. Phys Rev Lett 2019; 122:052701. [PMID: 30822026 DOI: 10.1103/physrevlett.122.052701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/15/2018] [Indexed: 06/09/2023]
Abstract
Detection of nuclear-decay γ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense γ-ray flux is thought to be annihilation radiation from the β^{+} decay of ^{18}F, which is destroyed prior to decay by the ^{18}F(p,α)^{15}O reaction. Estimates of ^{18}F production had been uncertain, however, because key near-threshold levels in the compound nucleus, ^{19}Ne, had yet to be identified. We report the first measurement of the ^{19}F(^{3}He,tγ)^{19}Ne reaction, in which the placement of two long-sought 3/2^{+} levels is suggested via triton-γ-γ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of 1.5-17 at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.
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Affiliation(s)
- M R Hall
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - D W Bardayan
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - T Baugher
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA
| | - A Lepailleur
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA
| | - S D Pain
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A Ratkiewicz
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA
| | - S Ahn
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - J M Allen
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - J T Anderson
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A D Ayangeakaa
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J C Blackmon
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - S Burcher
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M P Carpenter
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S M Cha
- Department of Physics, Sungkyunkwan University, Suwon 16419, South Korea
| | - K Y Chae
- Department of Physics, Sungkyunkwan University, Suwon 16419, South Korea
| | - K A Chipps
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J A Cizewski
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA
| | - M Febbraro
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - O Hall
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - J Hu
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - C L Jiang
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K L Jones
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - E J Lee
- Department of Physics, Sungkyunkwan University, Suwon 16419, South Korea
| | - P D O'Malley
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - S Ota
- Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - B C Rasco
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - D Santiago-Gonzalez
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - D Seweryniak
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - H Sims
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA
- Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - K Smith
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - W P Tan
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - P Thompson
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - C Thornsberry
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - R L Varner
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - D Walter
- Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903, USA
| | - G L Wilson
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
- Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA
| | - S Zhu
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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9
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Lindstrøm CA, Adli E, Allen JM, An W, Beekman C, Clarke CI, Clayton CE, Corde S, Doche A, Frederico J, Gessner SJ, Green SZ, Hogan MJ, Joshi C, Litos M, Lu W, Marsh KA, Mori WB, O'Shea BD, Vafaei-Najafabadi N, Yakimenko V. Measurement of Transverse Wakefields Induced by a Misaligned Positron Bunch in a Hollow Channel Plasma Accelerator. Phys Rev Lett 2018; 120:124802. [PMID: 29694092 DOI: 10.1103/physrevlett.120.124802] [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] [Received: 11/07/2017] [Indexed: 06/08/2023]
Abstract
Hollow channel plasma wakefield acceleration is a proposed method to provide high acceleration gradients for electrons and positrons alike: a key to future lepton colliders. However, beams which are misaligned from the channel axis induce strong transverse wakefields, deflecting beams and reducing the collider luminosity. This undesirable consequence sets a tight constraint on the alignment accuracy of the beam propagating through the channel. Direct measurements of beam misalignment-induced transverse wakefields are therefore essential for designing mitigation strategies. We present the first quantitative measurements of transverse wakefields in a hollow plasma channel, induced by an off-axis 20 GeV positron bunch, and measured with another 20 GeV lower charge trailing positron probe bunch. The measurements are largely consistent with theory.
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Affiliation(s)
- C A Lindstrøm
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - E Adli
- Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - J M Allen
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - W An
- Department of Electrical Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - C Beekman
- LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91762 Palaiseau, France
| | - C I Clarke
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C E Clayton
- Department of Electrical Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - S Corde
- LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91762 Palaiseau, France
| | - A Doche
- LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91762 Palaiseau, France
| | - J Frederico
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S J Gessner
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S Z Green
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M J Hogan
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C Joshi
- Department of Electrical Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - M Litos
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - W Lu
- IFSA Collaborative Innovation Center, Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - K A Marsh
- Department of Electrical Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - B D O'Shea
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - N Vafaei-Najafabadi
- Department of Electrical Engineering, University of California-Los Angeles, Los Angeles, California 90095, USA
| | - V Yakimenko
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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10
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Doche A, Beekman C, Corde S, Allen JM, Clarke CI, Frederico J, Gessner SJ, Green SZ, Hogan MJ, O'Shea B, Yakimenko V, An W, Clayton CE, Joshi C, Marsh KA, Mori WB, Vafaei-Najafabadi N, Litos MD, Adli E, Lindstrøm CA, Lu W. Acceleration of a trailing positron bunch in a plasma wakefield accelerator. Sci Rep 2017; 7:14180. [PMID: 29079817 PMCID: PMC5660186 DOI: 10.1038/s41598-017-14524-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/11/2017] [Indexed: 11/21/2022] Open
Abstract
High gradients of energy gain and high energy efficiency are necessary parameters for compact, cost-efficient and high-energy particle colliders. Plasma Wakefield Accelerators (PWFA) offer both, making them attractive candidates for next-generation colliders. In these devices, a charge-density plasma wave is excited by an ultra-relativistic bunch of charged particles (the drive bunch). The energy in the wave can be extracted by a second bunch (the trailing bunch), as this bunch propagates in the wake of the drive bunch. While a trailing electron bunch was accelerated in a plasma with more than a gigaelectronvolt of energy gain, accelerating a trailing positron bunch in a plasma is much more challenging as the plasma response can be asymmetric for positrons and electrons. We report the demonstration of the energy gain by a distinct trailing positron bunch in a plasma wakefield accelerator, spanning nonlinear to quasi-linear regimes, and unveil the beam loading process underlying the accelerator energy efficiency. A positron bunch is used to drive the plasma wake in the experiment, though the quasi-linear wake structure could as easily be formed by an electron bunch or a laser driver. The results thus mark the first acceleration of a distinct positron bunch in plasma-based particle accelerators.
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Affiliation(s)
- A Doche
- LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Universite Paris-Saclay, 91762, Palaiseau, France.
| | - C Beekman
- LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Universite Paris-Saclay, 91762, Palaiseau, France
| | - S Corde
- LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Universite Paris-Saclay, 91762, Palaiseau, France.
| | - J M Allen
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - C I Clarke
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - J Frederico
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - S J Gessner
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - S Z Green
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - M J Hogan
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - B O'Shea
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - V Yakimenko
- SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - W An
- University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - C E Clayton
- University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - C Joshi
- University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - K A Marsh
- University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - W B Mori
- University of California Los Angeles, Los Angeles, CA, 90095, USA
| | | | - M D Litos
- University of Colorado Boulder, Boulder, CO, 80309, USA
| | - E Adli
- Department of Physics, University of Oslo, 0316, Oslo, Norway
| | - C A Lindstrøm
- Department of Physics, University of Oslo, 0316, Oslo, Norway
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing, 10084, China
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11
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Pavlick D, Schrock AB, Malicki D, Stephens PJ, Kuo DJ, Ahn H, Turpin B, Allen JM, Rosenzweig M, Badizadegan K, Ross JS, Miller VA, Wong V, Ali SM. Identification of NTRK fusions in pediatric mesenchymal tumors. Pediatr Blood Cancer 2017; 64. [PMID: 28097808 DOI: 10.1002/pbc.26433] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND NTRK fusions are known oncogenic drivers and have recently been effectively targeted by investigational agents in adults. We sought to assess the frequency of NTRK fusions in a large series of pediatric and adolescent patients with advanced cancers. PROCEDURE Genomic profiles from 2,031 advanced cancers from patients less than 21 years old who were assayed with comprehensive genomic profiling were reviewed to identify NTRK fusions. RESULTS Total of nine cases (0.44%) harbored NTRK fusions, including novel partners. Four of these cases were in children less than 2 years old for which infantile fibrosarcoma was considered as a diagnosis, and two harbored the canonical ETV6-NTRK3. The remaining cases carried other diagnoses, at least one that carried the diagnosis of inflammatory myofibroblastic tumor. CONCLUSIONS NTRK fusions occur in a subset of young patients with mesenchymal or sarcoma-like tumors at a low frequency, and are eminently druggable targets via either investigational agents or approved drugs.
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Affiliation(s)
- Dean Pavlick
- Foundation Medicine, Inc., Cambridge, Massachusetts
| | | | - Denise Malicki
- Department of Pathology, University of California San Diego School of Medicine, La Jolla, California.,Department of Pathology, Rady Children's Hospital San Diego, San Diego, California
| | | | - Dennis J Kuo
- Division of Pediatric Hematology/Oncology, Rady Children's Hospital San Diego, San Diego, California
| | - Hyunah Ahn
- Division of Pediatric Hematology/Oncology, Rady Children's Hospital San Diego, San Diego, California
| | - Brian Turpin
- Division of Pediatric Hematology/Oncology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | | | | | | | - Jeffrey S Ross
- Foundation Medicine, Inc., Cambridge, Massachusetts.,Department of Pathology, Albany Medical Center, Albany, New York
| | | | - Victor Wong
- Division of Pediatric Hematology/Oncology, Rady Children's Hospital San Diego, San Diego, California
| | - Siraj M Ali
- Foundation Medicine, Inc., Cambridge, Massachusetts
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12
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Allen JM, Schrock AB, Erlich RL, Miller VA, Stephens PJ, Ross JS, Ou SHI, Ali SM, Vafai D. Genomic Profiling of Circulating Tumor DNA in Relapsed EGFR-mutated Lung Adenocarcinoma Reveals an Acquired FGFR3-TACC3 Fusion. Clin Lung Cancer 2016; 18:e219-e222. [PMID: 28089157 DOI: 10.1016/j.cllc.2016.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/13/2016] [Indexed: 01/29/2023]
Affiliation(s)
| | | | | | | | | | | | - Sai-Hong Ignatius Ou
- Department of Medicine, Division of Hematology-Oncology, University of California, Irvine, School of Medicine, Chao Family Comprehensive Cancer Center, Orange, CA
| | | | - Davood Vafai
- Eisenhower Lucy Curci Cancer Center, Rancho Mirage, CA
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13
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Hill A, Waller KA, Cui Y, Allen JM, Smits P, Zhang LX, Ayturk UM, Hann S, Lessard SG, Zurakowski D, Warman ML, Jay GD. Lubricin restoration in a mouse model of congenital deficiency. Arthritis Rheumatol 2016. [PMID: 26216721 DOI: 10.1002/art.39276] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Congenital deficiency of the principal boundary lubricant in cartilage (i.e., lubricin, encoded by the gene PRG4) increases joint friction and causes progressive joint failure. This study was undertaken to determine whether restoring lubricin expression in a mouse model would prevent, delay, or reverse the disease process caused by congenital deficiency. METHODS Using genetically engineered lubricin-deficient mice, we restored gene function before conception or at ages 3 weeks, 2 months, or 6 months after birth. The effect of restoring gene function (i.e., expression of lubricin) on the tibiofemoral patellar joints of mice was evaluated histologically and by ex vivo biomechanical testing. RESULTS Restoring gene function in mice prior to conception prevented joint disease. In 3-week-old mice, restoring gene function improved, but did not normalize, histologic features of the articular cartilage and whole-joint friction. In addition, cyclic loading of the joints produced fewer activated caspase 3-containing chondrocytes when lubricin expression was restored, as compared to that in littermate mice whose gene function was not restored (nonrestored controls). Restoration of lubricin expression in 2-month-old or 6-month-old mice had no beneficial effect on histopathologic cartilage damage, extent of whole-joint friction, or activation of caspase 3 when compared to nonrestored controls. CONCLUSION When boundary lubrication is congenitally deficient and cartilage becomes damaged, the window of opportunity for restoring lubrication and slowing disease progression is limited.
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Affiliation(s)
- Adele Hill
- Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Kimberly A Waller
- Alpert Medical School of Brown University and Rhode Island Hospital, Providence
| | - Yajun Cui
- Boston Children's Hospital, Boston, Massachusetts
| | - Justin M Allen
- Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | | | - Ling X Zhang
- Alpert Medical School of Brown University and Rhode Island Hospital, Providence
| | - Ugur M Ayturk
- Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Steven Hann
- Boston Children's Hospital, Boston, Massachusetts
| | | | | | - Matthew L Warman
- Howard Hughes Medical Institute, Boston Children's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Gregory D Jay
- Rhode Island Hospital, Alpert Medical School of Brown University, and Brown University School of Engineering, Providence, Rhode Island
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14
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Elleri D, Biagioni M, Allen JM, Kumareswaran K, Leelarathna L, Caldwell K, Nodale M, Wilinska ME, Haidar A, Calhoun P, Kollman C, Jackson NC, Umpleby AM, Acerini CL, Dunger DB, Hovorka R. Safety, efficacy and glucose turnover of reduced prandial boluses during closed-loop therapy in adolescents with type 1 diabetes: a randomized clinical trial. Diabetes Obes Metab 2015; 17:1173-9. [PMID: 26257323 PMCID: PMC4832358 DOI: 10.1111/dom.12549] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/20/2015] [Accepted: 07/31/2015] [Indexed: 01/27/2023]
Abstract
AIMS To evaluate safety, efficacy and glucose turnover during closed-loop with meal announcement using reduced prandial insulin boluses in adolescents with type 1 diabetes (T1D). METHODS We conducted a randomized crossover study comparing closed-loop therapy with standard prandial insulin boluses versus closed-loop therapy with prandial boluses reduced by 25%. Eight adolescents with T1D [3 males; mean (standard deviation) age 15.9 (1.5) years, glycated haemoglobin 74 (17) mmol/mol; median (interquartile range) total daily dose 0.9 (0.7, 1.1) IU/kg/day] were studied on two 36-h-long visits. In random order, subjects received closed-loop therapy with either standard or reduced insulin boluses administered with main meals (50-80 g carbohydrates) but not with snacks (15-30 g carbohydrates). Stable-label tracer dilution methodology measured total glucose appearance (Ra_total) and glucose disposal (Rd). RESULTS The median (interquartile range) time spent in target (3.9-10 mmol/l) was similar between the two interventions [74 (66, 84)% vs 80 (65, 96)%; p = 0.87] as was time spent above 10 mmol/l [21.8 (16.3, 33.5)% vs 18.0 (4.1, 34.2)%; p = 0.87] and below 3.9 mmol/l [0 (0, 1.5)% vs 0 (0, 1.8)%; p = 0.88]. Mean plasma glucose was identical during the two interventions [8.4 (0.9) mmol/l; p = 0.98]. Hypoglycaemia occurred once 1.5 h post-meal during closed-loop therapy with standard bolus. Overall insulin delivery was lower with reduced prandial boluses [61.9 (55.2, 75.0) vs 72.5 (63.6, 80.3) IU; p = 0.01] and resulted in lower mean plasma insulin concentration [186 (171, 260) vs 252 (198, 336) pmol/l; p = 0.002]. Lower plasma insulin was also documented overnight [160 (136, 192) vs 191 (133, 252) pmol/l; p = 0.01, pooled nights]. Ra_total was similar [26.3 (21.9, 28.0) vs 25.4 (21.0, 29.2) µmol/kg/min; p = 0.19] during the two interventions as was Rd [25.8 (21.0, 26.9) vs 25.2 (21.2, 28.8) µmol/kg/min; p = 0.46]. CONCLUSIONS A 25% reduction in prandial boluses during closed-loop therapy maintains similar glucose control in adolescents with T1D whilst lowering overall plasma insulin levels. It remains unclear whether closed-loop therapy with a 25% reduction in prandial boluses would prevent postprandial hypoglycaemia.
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Affiliation(s)
- D Elleri
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - M Biagioni
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - J M Allen
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - K Kumareswaran
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - L Leelarathna
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - K Caldwell
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - M Nodale
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - M E Wilinska
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - A Haidar
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - P Calhoun
- The Jaeb Center for Health Research, Tampa, FL, USA
| | - C Kollman
- The Jaeb Center for Health Research, Tampa, FL, USA
| | - N C Jackson
- Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - A M Umpleby
- Diabetes and Metabolic Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - C L Acerini
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - D B Dunger
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - R Hovorka
- Department of Paediatrics, University of Cambridge, Cambridge, UK
- Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
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15
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Thabit H, Tauschmann M, Allen JM, Leelarathna L, Hartnell S, Wilinska ME, Acerini CL, Dellweg S, Benesch C, Heinemann L, Mader JK, Holzer M, Kojzar H, Exall J, Yong J, Pichierri J, Barnard KD, Kollman C, Cheng P, Hindmarsh PC, Campbell FM, Arnolds S, Pieber TR, Evans ML, Dunger DB, Hovorka R. Home Use of an Artificial Beta Cell in Type 1 Diabetes. N Engl J Med 2015; 373:2129-2140. [PMID: 26379095 PMCID: PMC4697362 DOI: 10.1056/nejmoa1509351] [Citation(s) in RCA: 315] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The feasibility, safety, and efficacy of prolonged use of an artificial beta cell (closed-loop insulin-delivery system) in the home setting have not been established. METHODS In two multicenter, crossover, randomized, controlled studies conducted under free-living home conditions, we compared closed-loop insulin delivery with sensor-augmented pump therapy in 58 patients with type 1 diabetes. The closed-loop system was used day and night by 33 adults and overnight by 25 children and adolescents. Participants used the closed-loop system for a 12-week period and sensor-augmented pump therapy (control) for a similar period. The primary end point was the proportion of time that the glucose level was between 70 mg and 180 mg per deciliter for adults and between 70 mg and 145 mg per deciliter for children and adolescents. RESULTS Among adults, the proportion of time that the glucose level was in the target range was 11.0 percentage points (95% confidence interval [CI], 8.1 to 13.8) greater with the use of the closed-loop system day and night than with control therapy (P<0.001). The mean glucose level was lower during the closed-loop phase than during the control phase (difference, -11 mg per deciliter; 95% CI, -17 to -6; P<0.001), as were the area under the curve for the period when the glucose level was less than 63 mg per deciliter (39% lower; 95% CI, 24 to 51; P<0.001) and the mean glycated hemoglobin level (difference, -0.3%; 95% CI, -0.5 to -0.1; P=0.002). Among children and adolescents, the proportion of time with the nighttime glucose level in the target range was higher during the closed-loop phase than during the control phase (by 24.7 percentage points; 95% CI, 20.6 to 28.7; P<0.001), and the mean nighttime glucose level was lower (difference, -29 mg per deciliter; 95% CI, -39 to -20; P<0.001). The area under the curve for the period in which the day-and-night glucose levels were less than 63 mg per deciliter was lower by 42% (95% CI, 4 to 65; P=0.03). Three severe hypoglycemic episodes occurred during the closed-loop phase when the closed-loop system was not in use. CONCLUSIONS Among patients with type 1 diabetes, 12-week use of a closed-loop system, as compared with sensor-augmented pump therapy, improved glucose control, reduced hypoglycemia, and, in adults, resulted in a lower glycated hemoglobin level. (Funded by the JDRF and others; AP@home04 and APCam08 ClinicalTrials.gov numbers, NCT01961622 and NCT01778348.).
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16
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Corde S, Adli E, Allen JM, An W, Clarke CI, Clayton CE, Delahaye JP, Frederico J, Gessner S, Green SZ, Hogan MJ, Joshi C, Lipkowitz N, Litos M, Lu W, Marsh KA, Mori WB, Schmeltz M, Vafaei-Najafabadi N, Walz D, Yakimenko V, Yocky G. Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield. Nature 2015; 524:442-5. [PMID: 26310764 DOI: 10.1038/nature14890] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 06/30/2015] [Indexed: 11/09/2022]
Abstract
Electrical breakdown sets a limit on the kinetic energy that particles in a conventional radio-frequency accelerator can reach. New accelerator concepts must be developed to achieve higher energies and to make future particle colliders more compact and affordable. The plasma wakefield accelerator (PWFA) embodies one such concept, in which the electric field of a plasma wake excited by a bunch of charged particles (such as electrons) is used to accelerate a trailing bunch of particles. To apply plasma acceleration to electron-positron colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas. Although substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch, such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFAs where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered--'self-loaded'--so that about a billion positrons gain five gigaelectronvolts of energy with a narrow energy spread over a distance of just 1.3 metres. They extract about 30 per cent of the wake's energy and form a spectrally distinct bunch with a root-mean-square energy spread as low as 1.8 per cent. This ability to transfer energy efficiently from the front to the rear within a single positron bunch makes the PWFA scheme very attractive as an energy booster to an electron-positron collider.
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Affiliation(s)
- S Corde
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.,LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91762 Palaiseau, France
| | - E Adli
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.,Department of Physics, University of Oslo, 0316 Oslo, Norway
| | - J M Allen
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - W An
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.,Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - C I Clarke
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C E Clayton
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - J P Delahaye
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J Frederico
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S Gessner
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S Z Green
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M J Hogan
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - C Joshi
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - N Lipkowitz
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Litos
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - W Lu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, China
| | - K A Marsh
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - W B Mori
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.,Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA
| | - M Schmeltz
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - N Vafaei-Najafabadi
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA
| | - D Walz
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - V Yakimenko
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - G Yocky
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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17
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Thabit H, Elleri D, Leelarathna L, Allen JM, Lubina-Solomon A, Stadler M, Walkinshaw E, Iqbal A, Choudhary P, Wilinska ME, Barnard KD, Heller SR, Amiel SA, Evans ML, Dunger DB, Hovorka R. Unsupervised home use of an overnight closed-loop system over 3-4 weeks: a pooled analysis of randomized controlled studies in adults and adolescents with type 1 diabetes. Diabetes Obes Metab 2015; 17:452-8. [PMID: 25492378 PMCID: PMC4510702 DOI: 10.1111/dom.12427] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/01/2014] [Accepted: 12/04/2014] [Indexed: 12/25/2022]
Abstract
AIMS To compare overnight closed-loop and sensor-augmented pump therapy in patients with type 1 diabetes by combining data collected during free-living unsupervised randomized crossover home studies. METHODS A total of 40 participants with type 1 diabetes, of whom 24 were adults [mean ± standard deviation (s.d.) age 43 ± 12 years and glycated haemoglobin (HbA1c) 8.0 ± 0.9%] and 16 were adolescents (mean ± s.d. age 15.6 ± 3.6 years and HbA1c 8.1 ± 0.8%), underwent two periods of sensor-augmented pump therapy in the home setting, in combination with or without an overnight closed-loop insulin delivery system that uses a model predictive control algorithm to direct insulin delivery. The order of the two interventions was random; each period lasted 4 weeks in adults and 3 weeks in adolescents. The primary outcome was time during which sensor glucose readings were in the target range of 3.9-8.0 mmol/l. RESULTS The proportion of time when sensor glucose was in the target range (3.9-8.0 mmol/l) overnight (between 24:00 and 08:00 hours) was 18.5% greater during closed-loop insulin delivery than during sensor-augmented therapy (p < 0.001). Closed-loop therapy significantly reduced mean overnight glucose levels by 0.9 mmol/l (p < 0.001), with no difference in glycaemic variability, as measured by the standard deviation of sensor glucose. Time spent above the target range was reduced (p = 0.001), as was time spent in hypoglycaemia (<3.9 mmol/l; p = 0.014) during closed-loop therapy. Lower mean overnight glucose levels during closed-loop therapy were brought about by increased overnight insulin delivery (p < 0.001) without changes to the total daily delivery (p = 0.84). CONCLUSION Overnight closed-loop insulin therapy at home in adults and adolescents with type 1 diabetes is feasible, showing improvements in glucose control and reducing the risk of nocturnal hypoglycaemia.
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Affiliation(s)
- H Thabit
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
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Thabit H, Kumareswaran K, Haidar A, Leelarathna L, Caldwell K, Elleri D, Allen JM, Nodale M, Wilinska ME, Jackson NC, Umpleby AM, Evans ML, Hovorka R. Glucose turnover after replacement of usual therapy by insulin in insulin-naive type 2 diabetes subjects. J Clin Endocrinol Metab 2014; 99:2225-32. [PMID: 24606105 DOI: 10.1210/jc.2013-4519] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
CONTEXT Discontinuation of anti-hyperglycemic oral agents and initiation of insulin is recommended in certain clinical situations for inpatients with type 2 diabetes (T2D). The effects on glucose turnover when these agents are acutely withdrawn are poorly understood and may be of importance when insulin therapy is initiated. OBJECTIVE Our objective was to investigate alterations in glucose turnover after acute withdrawal of noninsulin therapy. DESIGN AND SETTING This was a randomized crossover study at a clinical research facility. PARTICIPANTS Participants included 12 insulin-naive subjects with T2D. METHODS Subjects attended two 24-hour visits. Standard therapy was discontinued and replaced by closed-loop insulin delivery during the intervention visit. Usual anti-hyperglycemic therapy was continued during the control visit. Systemic glucose appearance (Ra) and glucose disposal (Rd) were measured using a tracer dilution technique with iv [6,6-(2)H2]glucose. RESULTS Plasma glucose profiles during both visits were comparable (P = .48). Glucose Ra increased during the day (21.4 [19.5, 23.5] vs 18.6 [17.0, 21.6) μmol/kg/min, P = .019) and decreased overnight (9.7 [8.5, 11.4] vs 11.6 [10.3, 12.9] μmol/kg/min, P = .004) when the usual therapy was discontinued and replaced with insulin. Increased daytime glucose Rd (21.2 [19.4, 23.9] vs 18.8 [18.3, 21.7] μmol/kg/min, P = .002) and decreased overnight Rd (10.4 [9.1, 12.0] vs 11.8 [10.7, 13.7] μmol/kg/min, P = .005) were observed when the usual therapy was discontinued, whereas daytime peripheral insulin sensitivity was reduced (47.8 [24.8, 66.1] vs 62.5 [34.8, 75.8] nmol/kg/min per pmol/L, P = .034). CONCLUSION In T2D, acute discontinuation of anti-hyperglycemic therapy and replacement with insulin increases postprandial Ra and reduces peripheral insulin sensitivity. Insulin dose initiation may need to compensate for these alterations.
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Affiliation(s)
- H Thabit
- Metabolic Research Laboratories (H.T., K.K., L.L., K.C., D.E., J.M.A., M.N., M.E.W., M.L.E., R.H.), Wellcome Trust-Medical Research Council Institute of Metabolic Science, and Department of Paediatrics (D.E., J.M.A., M.E.W., R.H.), University of Cambridge, Cambridge CB2 0QQ, United Kingdom; Centre for Intelligent Machines (A.H.), McGill University, Montreal, Quebec H3A 0E9, Canada; and Postgraduate Medical School (N.C.J., A.M.U.), University of Surrey, Guildford GU2 7TE, United Kingdom
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Allen JM, McGlinn E, Hill A, Warman ML. Autopodial development is selectively impaired by misexpression of chordin-like 1 in the chick limb. Dev Biol 2013; 381:159-69. [DOI: 10.1016/j.ydbio.2013.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/22/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022]
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Elleri D, Allen JM, Harris J, Kumareswaran K, Nodale M, Leelarathna L, Acerini CL, Haidar A, Wilinska ME, Jackson N, Umpleby AM, Evans ML, Dunger DB, Hovorka R. Absorption patterns of meals containing complex carbohydrates in type 1 diabetes. Diabetologia 2013; 56:1108-17. [PMID: 23435829 DOI: 10.1007/s00125-013-2852-x] [Citation(s) in RCA: 33] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 01/21/2013] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Successful postprandial glycaemia management requires understanding of absorption patterns after meals containing variable complex carbohydrates. We studied eight young participants with type 1 diabetes to investigate a large low-glycaemic-load (LG) meal and another eight participants to investigate a high-glycaemic-load (HG) meal matched for carbohydrates (121 g). METHODS On Visit 1, participants consumed an evening meal. On follow-up Visit 2, a variable-target glucose clamp was performed to reproduce glucose and insulin levels from Visit 1. Adopting stable-label tracer dilution methodology, we measured endogenous glucose production on Visit 2 and subtracted it from total glucose appearance measured on Visit 1 to obtain meal-attributable glucose appearance. RESULTS After the LG meal, 25%, 50% and 75% of cumulative glucose appearance was at 88 ± 21, 175 ± 39 and 270 ± 54 min (mean ± SD), whereas glucose from the HG meal appeared significantly faster at 56 ± 12, 100 ± 25 and 153 ± 39 min (p < 0.001 to 0.003), and resulted in a 50% higher peak appearance (p < 0.001). Higher apparent bioavailability by 15% (p = 0.037) was observed after the LG meal. We documented a 20 min deceleration of dietary mixed carbohydrates compared with dietary glucose for the HG meal and a twofold deceleration for the LG meal. CONCLUSIONS/INTERPRETATION Absorption patterns may be influenced by glycaemic load and/or meal composition, affecting optimum prandial insulin dosing in type 1 diabetes.
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Affiliation(s)
- D Elleri
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Box 289, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
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Hansen U, Allen JM, White R, Moscibrocki C, Bruckner P, Bateman JF, Fitzgerald J. WARP interacts with collagen VI-containing microfibrils in the pericellular matrix of human chondrocytes. PLoS One 2012; 7:e52793. [PMID: 23300779 PMCID: PMC3530481 DOI: 10.1371/journal.pone.0052793] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 11/21/2012] [Indexed: 11/19/2022] Open
Abstract
Collagen VI and WARP are extracellular structural macromolecules present in cartilage and associated with BM suprastructures in non-skeletal tissues. We have previously shown that in WARP-deficient mice, collagen VI is specifically reduced in regions of the peripheral nerve ECM where WARP is expressed, suggesting that both macromolecules are part of the same suprastructure. The object of this study was to conduct a detailed analysis of WARP-collagen VI interactions in vitro in cartilage, a tissue rich in WARP and collagen VI. Immunohistochemical analysis of mouse and human articular cartilage showed that WARP and collagen VI co-localize in the pericellular matrix of superficial zone articular chondrocytes. EM analysis on extracts of human articular cartilage showed that WARP associates closely with collagen VI-containing suprastructures. Additional evidence of an interaction is provided by immunogold EM and immunoblot analysis showing that WARP was present in collagen VI-containing networks isolated from cartilage. Further characterization were done by solid phase binding studies and reconstitution experiments using purified recombinant WARP and isolated collagen VI. Collagen VI binds to WARP with an apparent K(d) of approximately 22 nM and the binding site(s) for WARP resides within the triple helical domain since WARP binds to both intact collagen VI tetramers and pepsinized collagen VI. Together, these data confirm and extend our previous findings by demonstrating that WARP and collagen VI form high affinity associations in vivo in cartilage. We conclude that WARP is ideally placed to function as an adapter protein in the cartilage pericellular matrix.
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Affiliation(s)
- Uwe Hansen
- Institute for Physiological Chemistry and Pathobiochemistry, University Hospital of Muenster, Muenster, Germany
| | - Justin M. Allen
- Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, and University of Melbourne, Parkville, Victoria, Australia
| | - Rachel White
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Cathleen Moscibrocki
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Peter Bruckner
- Institute for Physiological Chemistry and Pathobiochemistry, University Hospital of Muenster, Muenster, Germany
| | - John F. Bateman
- Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Jamie Fitzgerald
- Department of Orthopaedics and Rehabilitation, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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Abstract
AIMS There are previous suggestions of increased C-peptide concentration in women with Type 1 diabetes during pregnancy. Our aim was to re-evaluate the hypothesis of a pregnancy-induced increase by measuring plasma C-peptide concentration in women with stable blood glucose control under standardized fasting and meal-stimulated conditions. METHODS Ten women with Type 1 diabetes; median age 31.1 years, median diabetes duration 19 years, median HbA(1c) 52 mmol/mol (6.9%) were admitted to a clinical research facility for two 24-h visits in early (12-16 weeks) and late (28-32 weeks) pregnancy. Women They ate standardized study meals - 80-g carbohydrate dinner, 60-g carbohydrate breakfast, and fasted between meals and overnight. Closed-loop insulin delivery maintained stable and comparable glycaemic conditions. Paired samples for plasma glucose and C-peptide were obtained. RESULTS Plasma glucose levels were comparable in early (median 6.5 mmol/l; interquartile range 5.6-8.6) and late pregnancy (median 7.0 mmol/l; interquartile range 6.1-7.8; P = 0.72). There was no change in fasting or meal-stimulated plasma C-peptide concentration from early to late pregnancy; mean difference 4.0 pmol/l (95% CI -6.0 to 7.0; P = 0.9). Four women had detectable C-peptide; peak (range) early vs. late pregnancy 48.5 (10-115) vs. 40.0 pmol/l (80-105); P = 0.5, which was weakly associated with plasma glucose; R(2) = 0.15, P < 0.0001. CONCLUSIONS We found no gestational changes in plasma C-peptide concentration. Previously reported increases may reflect differences in glucose control and/or exogenous insulin doses. This study highlights the importance and challenges of standardizing experimental conditions for accurate plasma C-peptide measurement during Type 1 diabetes pregnancy.
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Affiliation(s)
- H R Murphy
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
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Murphy HR, Elleri D, Allen JM, Harris J, Simmons D, Rayman G, Temple RC, Umpleby AM, Dunger DB, Haidar A, Nodale M, Wilinska ME, Hovorka R. Pathophysiology of postprandial hyperglycaemia in women with type 1 diabetes during pregnancy. Diabetologia 2012; 55:282-93. [PMID: 22080230 DOI: 10.1007/s00125-011-2363-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 10/04/2011] [Indexed: 01/22/2023]
Abstract
AIMS/HYPOTHESIS Although maternal hyperglycaemia is associated with increased risk of adverse pregnancy outcome, the mechanisms of postprandial hyperglycaemia during pregnancy are poorly understood. We aimed to describe glucose turnover in pregnant women with type 1 diabetes, according to stage of gestation (early vs late gestation). METHODS The rates of systemic glucose appearance (R(a)) and glucose disposal (R(d)) were measured in ten pregnant women with type 1 diabetes during early (12-16 weeks) and late (28-32 weeks) gestation. Women ate standardised meals--a starch-rich 80 g carbohydrate dinner and a sugar-rich 60 g carbohydrate breakfast--and fasted between meals and overnight. Stable-label isotope tracers ([6,6-(2)H(2)]glucose and [U-(13)C]glucose) were used to determine R(a), R(d) and glucose bioavailability. Closed-loop insulin delivery maintained stable glycaemic conditions. RESULTS There were no changes in fasting R(a) (10 ± 2 vs 11 ± 2 μmol kg(-1) min(-1); p = 0.32) or fasting R(d) (11 ± 2 vs 11 ± 1 μmol kg(-1) min(-1); p = 0.77) in early vs late gestation. There was increased hepatic insulin resistance (381 ± 237 vs 540 ± 242 μmol kg(-1) min(-1) × pmol/l; p = 0.04) and decreased peripheral insulin sensitivity (0.09 ± 0.04 vs 0.05 ± 0.02 μmol kg(-1) min(-1) per pmol/l dinner, 0.11 ± 0.05 vs 0.07 ± 0.03 μmol kg(-1) min(-1) per pmol/l breakfast; p = 0.002) in late gestation. It also took longer for insulin levels to reach maximal concentrations (49 [37-55] vs 71 [52-108] min; p = 0.004) with significantly delayed glucose disposal (108 [87-125] vs 135 [110-158] min; p = 0.005) in late gestation. CONCLUSIONS/INTERPRETATION Postprandial glucose control is impaired by significantly slower glucose disposal in late gestation. Early prandial insulin dosing may help to accelerate glucose disposal and potentially ameliorate postprandial hyperglycaemia in late pregnancy. TRIAL REGISTRATION ISRCTN 62568875 FUNDING Diabetes UK Project Grant BDA 07/003551. H.R. Murphy is funded by a National Institute for Health Research (NIHR) research fellowship (PDF/08/01/036). Supported also by the Juvenile Diabetes Research Foundation (JDRF), Abbott Diabetes Care (Freestyle Navigator CGM and sensors free of charge), Medical Research Council Centre for Obesity and Related Metabolic Diseases and NIHR Cambridge Biomedical Research Centre.
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Affiliation(s)
- H R Murphy
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Institute of Metabolic Science, Box 289, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
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Robbins J, Dalla Rosa L, Allen JM, Mattila DK, Secchi ER, Friedlaender AS, Stevick PT, Nowacek DP, Steele D. Return movement of a humpback whale between the Antarctic Peninsula and American Samoa: a seasonal migration record. ENDANGER SPECIES RES 2011. [DOI: 10.3354/esr00328] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Bottomley PA, Kumar A, Edelstein WA, Allen JM, Karmarkar PV. Designing passive MRI-safe implantable conducting leads with electrodes. Med Phys 2010; 37:3828-43. [PMID: 20831091 DOI: 10.1118/1.3439590] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The presence of implanted electronic devices with conducting leads and electrodes are contraindicated for magnetic resonance imaging (MRI), denying many patients its potential benefits. The prime concern is MRI's radio frequency (RF) fields, which can cause elevated local specific absorption rates (SARs) and potential heat injury. The purpose of this article is to develop and compare a range of passive implantable "MRI-safe" lead designs. METHODS Conducting leads incorporating different lengths (3-75 cm), insulation thicknesses (0-105 microm), resistances (100-3000 omega), coiled conductors (inner diameter < or = 1.2 mm), high-impedance (135-2700 omega) RF traps, and single-coiled and triple-coiled coaxial-wound "billabong" leads with reversed coil sections that oppose and reduce the induced current, are investigated both experimentally using local temperature measurements, and by numerical full-wave electromagnetic field analysis of the local SAR, in three different-sized bioanalogous model saline-gel phantoms at 1.5 T MRI and 4 W/kg exposure. RESULTS In all designs, the maximum computed 1 g average SAR and experimental temperature rise occur at the bare electrodes. Electrode heating increases with lead insulation thickness and peaks for uncoiled leads 25-50 cm long. A reasonable match between computed SAR and the point SAR estimated from thermal sensors obtained by approximating the computation volume to that of the thermal probes. Factors that maximize the impedance of leads with resistive, coiled, RF trap and billabong elements can effectively limit heating below 1-2 degrees, but folded lead configurations can be a concern. The RF trap and billabong designs can both support multiple conductors and electrodes, with billabong prototype leads also heating <1 degrees C when tested for 3 T MRI. CONCLUSIONS Lead insulation and length strongly affect implanted lead safety to RF exposure during MRI. Lead designs employing impedance and reversed winding sections offer hope for the development of passive, MRI-safe, implantable conducting leads for future human use.
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Affiliation(s)
- Paul A Bottomley
- SurgiVision, Inc., Suite B307, 1101 East 33rd Street, Baltimore, Maryland 21218, USA.
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Hallam MJ, Allen JM, James SE, Donaldson PMW, Davies JG, Hanlon GW, Dheansa BS. Potential subtherapeutic linezolid and meropenem antibiotic concentrations in a patient with severe burns and sepsis. J Burn Care Res 2010; 31:207-9. [PMID: 20061858 DOI: 10.1097/bcr.0b013e3181c89ee3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Altered pharmacokinetics in patients with major burns may result in serum antibiotic concentrations below those required to be effective against the common pathogens encountered in burns patients. The major changes in the fluid volumes of key body compartments, which occur with a large burn, may increase the apparent volume of distribution of a drug, thereby lowering its concentration when a standard dose is given. In addition, the observed increase in renal blood flow reported in burns patients, because of the change in cardiac output, may result in a higher drug clearance and a shorter elimination half-life. As a consequence, studies have recommended higher doses or more frequent dosing or both for some antibiotics in patients with major burns, but data are lacking for many of the antibiotics reserved for treatment of life-threatening infections. The authors measured serum concentrations of two antibiotics, linezolid and meropenem, in an immunosuppressed patient who presented with a severe burn to determine whether therapeutic concentrations were achieved, thereby improving the likelihood of infection control.
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Affiliation(s)
- M-J Hallam
- Burns Centre, Queen Victoria Hospital, East Grinstead, UK
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Elleri D, Allen JM, Nodale M, Wilinska ME, Acerini CL, Dunger DB, Hovorka R. Suspended insulin infusion during overnight closed-loop glucose control in children and adolescents with Type 1 diabetes. Diabet Med 2010; 27:480-4. [PMID: 20536523 DOI: 10.1111/j.1464-5491.2010.02964.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS We assessed an extended interruption of subcutaneous insulin delivery during overnight closed-loop glucose control in children and adolescents with Type 1 diabetes (T1D). METHODS In seven young subjects with T1D [age 14.2+/-2.1 years, diabetes duration 6.9+/-4.0 years, glycated haemoglobin (HbA1c) 8.0+/-1.5%, body mass index (BMI) 21.4+/-4.0 kg/m2, total daily insulin dose 0.9+/-0.2 units/kg/day; mean+/-sd) participating in overnight closed-loop glucose control studies, insulin delivery was interrupted for at least 90 min on the basis of predicted hypoglycaemia, low prevailing glucose levels or a too-steep decline in glucose levels. RESULTS Insulin delivery was interrupted for 165 (105, 210) min [median, interquartile range (IQR)]. Plasma glucose was 6.2+/-3.2 mmol/l at the time of interruption and 5.5+/-2.0 mmol/l 105 min later (P=0.15, paired t-test). Plasma glucose declined during the first hour of the interruption at a rate of 0.02+/-0.03 mmol/l per min and reached a nadir of 5.2+/-2.7 mmol/l; 105 min after the interruption, plasma glucose was increasing at a rate of 0.01+/-0.03 mmol/l per min. When insulin delivery restarted, plasma glucose was 6.4+/-2.2 mmol/l and peaked at 7.9+/-2.1 mmol/l in 60 min (P=0.01). Physiological levels of plasma insulin were measured throughout with a nadir of 119+/-78 pmol/l. CONCLUSIONS A prolonged interruption of insulin delivery during overnight closed-loop glucose control to prevent hypoglycaemia was not associated with an increased risk of hyperglycaemia in young people with T1D.
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Affiliation(s)
- D Elleri
- Department of Paediatrics, University of Cambridge, Cambridge, UK
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Abstract
AIMS Using compartment modelling, we assessed the time delay between blood glucose and sensor glucose measured by the Guardian RT continuous glucose monitoring system in young subjects with Type 1 diabetes (T1D). METHODS Twelve children and adolescents with T1D treated by continuous subcutaneous insulin infusion (male/female 7/5; age 13.1 +/- 4.2 years; body mass index 21.9 +/- 4.3 kg/m(2); mean +/- sd) were studied over 19 h in a Clinical Research Facility. Guardian RT was calibrated every 6 h and sensor glucose measured every 5 min. Reference blood glucose was measured every 15 min using a YSI 2300 STAT Plus Analyser. A population compartment model of sensor glucose-blood glucose kinetics was adopted to estimate the time delay, the calibration scale and the calibration shift. RESULTS The population median of the time delay was 15.8 (interquartile range 15.2, 16.5) min, which was corroborated by correlation analysis between blood glucose and 15-min delayed sensor glucose. The delay has a relatively low intersubject variability, with 95% of individuals predicted to have delays between 10.4 and 24.3 min. Population medians (interquartile range) for the scale and shift are 0.800 (0.777, 0.823) (unitless) and 1.66 (1.47, 1.84) mmol/l, respectively. CONCLUSIONS In young subjects with T1D, the total time delay associated with the Guardian RT system was approximately 15 min. This is twice that expected on physiological grounds, suggesting a 5- to 10-min delay because of data processing. Delays above 25 min are rarely to be observed.
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Affiliation(s)
- C Wei
- MRC Biostatistics Unit, Institute of Public Health, University of Cambridge, Cambridge, UK.
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Raine AE, Allen JM, Ledingham JG, Bloom SR. Renovascular Distribution of Npy and its Vasoconstrictor and Natriuretic Properties. ACTA ACUST UNITED AC 2009; 6:1957-60. [PMID: 6549442 DOI: 10.3109/10641968409046109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Allen JM, Zamurs L, Brachvogel B, Schlötzer-Schrehardt U, Hansen U, Lamandé SR, Rowley L, Fitzgerald J, Bateman JF. Mice lacking the extracellular matrix protein WARP develop normally but have compromised peripheral nerve structure and function. J Biol Chem 2009; 284:12020-30. [PMID: 19279005 DOI: 10.1074/jbc.m806968200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
WARP is a recently identified extracellular matrix molecule with restricted expression in permanent cartilages and a distinct subset of basement membranes in peripheral nerves, muscle, and the central nervous system vasculature. WARP interacts with perlecan, and we also demonstrate here that WARP binds type VI collagen, suggesting a function in bridging connective tissue structures. To understand the in vivo function of WARP, we generated a WARP-deficient mouse strain. WARP-null mice were healthy, viable, and fertile with no overt abnormalities. Motor function and behavioral testing demonstrated that WARP-null mice exhibited a significantly delayed response to acute painful stimulus and impaired fine motor coordination, although general motor function was not affected, suggesting compromised peripheral nerve function. Immunostaining of WARP-interacting ligands demonstrated that the collagen VI microfibrillar matrix was severely reduced and mislocalized in peripheral nerves of WARP-null mice. Further ultrastructural analysis revealed reduced fibrillar collagen deposition within the peripheral nerve extracellular matrix and abnormal partial fusing of adjacent Schwann cell basement membranes, suggesting an important function for WARP in stabilizing the association of the collagenous interstitial matrix with the Schwann cell basement membrane. In contrast, other WARP-deficient tissues such as articular cartilage, intervertebral discs, and skeletal muscle showed no detectable abnormalities, and basement membranes formed normally. Our data demonstrate that although WARP is not essential for basement membrane formation or musculoskeletal development, it has critical roles in the structure and function of peripheral nerves.
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Affiliation(s)
- Justin M Allen
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
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Freeman S, Bartlett JB, Convey G, Hardern I, Teague JL, Loxham SJG, Allen JM, Poucher SM, Charles AD. Sensitivity of glycogen phosphorylase isoforms to indole site inhibitors is markedly dependent on the activation state of the enzyme. Br J Pharmacol 2006; 149:775-85. [PMID: 17016495 PMCID: PMC2014651 DOI: 10.1038/sj.bjp.0706925] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Inhibition of hepatic glycogen phosphorylase is a potential treatment for glycaemic control in type 2 diabetes. Selective inhibition of the liver phosphorylase isoform could minimize adverse effects in other tissues. We investigated the potential selectivity of two indole site phosphorylase inhibitors, GPi688 and GPi819. EXPERIMENTAL APPROACH The activity of glycogen phosphorylase was modulated using the allosteric effectors glucose or caffeine to promote the less active T state, and AMP to promote the more active R state. In vitro potency of indole site inhibitors against liver and muscle glycogen phosphorylase a was examined at different effector concentrations using purified recombinant enzymes. The potency of GPi819 was compared with its in vivo efficacy at raising glycogen concentrations in liver and muscle of Zucker (fa/fa) rats. KEY RESULTS In vitro potency of indole site inhibitors depended upon the activity state of phosphorylase a. Both inhibitors showed selectivity for liver phosphorylase a when the isoform specific activities were equal. After 5 days dosing of GPi819 (37.5 micromol kg(-1)), where free compound levels in plasma and tissue were at steady state, glycogen elevation was 1.5-fold greater in soleus muscle than in liver (P < 0.05). CONCLUSIONS AND IMPLICATIONS The in vivo selectivity of GPi819 did not match that seen in vitro when the specific activities of phosphorylase a isoforms are equal. This suggests T state promoters may be important physiological regulators in skeletal muscle. The greater efficacy of indole site inhibitors in skeletal muscle has implications for the overall safety profile of such drugs.
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Affiliation(s)
- S Freeman
- Cardiovascular and Gastrointestinal Discovery Department, AstraZeneca, Macclesfield, Cheshire, UK.
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Lamandé SR, Mörgelin M, Adams NE, Selan C, Allen JM. The C5 domain of the collagen VI alpha3(VI) chain is critical for extracellular microfibril formation and is present in the extracellular matrix of cultured cells. J Biol Chem 2006; 281:16607-14. [PMID: 16613849 DOI: 10.1074/jbc.m510192200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Collagen VI, a microfibrillar protein found in virtually all connective tissues, is composed of three distinct subunits, alpha1(VI), alpha2(VI), and alpha3(VI), which associate intracellularly to form triple helical heterotrimeric monomers then dimers and tetramers. The secreted tetramers associate end-to-end to form beaded microfibrils. Although the basic steps in assembly and the structure of the tetramers and microfibrils are well defined, details of the interacting protein domains involved in assembly are still poorly understood. To explore the role of the C-terminal globular regions in assembly, alpha3(VI) cDNA expression constructs with C-terminal truncations were stably transfected into SaOS-2 cells. Control alpha3(VI) N6-C5 chains with an intact C-terminal globular region (subdomains C1-C5), and truncated alpha3(VI) N6-C1, N6-C2, N6-C3, and N6-C4 chains, all associated with endogenous alpha1(VI) and alpha2(VI) to form collagen VI monomers, dimers and tetramers, which were secreted. These data demonstrate that subdomains C2-C5 are not required for monomer, dimer or tetramer assembly, and suggest that the important chain selection interactions involve the C1 subdomains. In contrast to tetramers containing control alpha3(VI) N6-C5 chains, tetramers containing truncated alpha3(VI) chains were unable to associate efficiently end-to-end in the medium and did not form a significant extracellular matrix, demonstrating that the alpha3(VI) C5 domain plays a crucial role in collagen VI microfibril assembly. The alpha3(VI) C5 domain is present in the extracellular matrix of SaOS-2 N6-C5 expressing cells and fibroblasts demonstrating that processing of the C-terminal region of the alpha3(VI) chain is not essential for microfibril formation.
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Affiliation(s)
- Shireen R Lamandé
- Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville 3052, Victoria, Australia.
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Allen JM, Bateman JF, Hansen U, Wilson R, Bruckner P, Owens RT, Sasaki T, Timpl R, Fitzgerald J. WARP is a novel multimeric component of the chondrocyte pericellular matrix that interacts with perlecan. J Biol Chem 2006; 281:7341-9. [PMID: 16407285 DOI: 10.1074/jbc.m513746200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
WARP is a novel member of the von Willebrand factor A domain superfamily of extracellular matrix proteins that is expressed by chondrocytes. WARP is restricted to the presumptive articular cartilage zone prior to joint cavitation and to the articular cartilage and fibrocartilaginous elements in the joint, spine, and sternum during mouse embryonic development. In mature articular cartilage, WARP is highly specific for the chondrocyte pericellular microenvironment and co-localizes with perlecan, a prominent component of the chondrocyte pericellular region. WARP is present in the guanidine-soluble fraction of cartilage matrix extracts as a disulfide-bonded multimer, indicating that WARP is a strongly interacting component of the cartilage matrix. To investigate how WARP is integrated with the pericellular environment, we studied WARP binding to mouse perlecan using solid phase and surface plasmon resonance analysis. WARP interacts with domain III-2 of the perlecan core protein and the heparan sulfate chains of the perlecan domain I with K(D) values in the low nanomolar range. We conclude that WARP forms macromolecular structures that interact with perlecan to contribute to the assembly and/or maintenance of "permanent" cartilage structures during development and in mature cartilages.
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Affiliation(s)
- Justin M Allen
- Cell and Matrix Biology Research Unit, Murdoch Childrens Research Institute and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Flemington Road, Parkville, Victoria 3052, Australia
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Abstract
Leptin is a hormonal protein involved in energy homeostatis that acts to inhibit food intake, to stimulate energy expenditure, and to influence insulin secretion, lipolysis, and sugar transport. Its action is mediated by a specific receptor whose activation is highly controversial. As a member of the cytokine receptor superfamily, it has been predicted to be activated by ligand-induced dimerization. However, recent evidence has indicated that this receptor exists as a dimer in both ligand-free and ligand-bound states. Here, the BiaCore has been used to measure the kinetics and stoichiometry of the interaction between the leptin and its receptor. Human or mouse receptor chimeras comprising two receptor extracellular domains fused to the Fc region of IgG(1) were captured on to the sensor via protein G. Kinetic data fitted to the simplest 1/1 model. The observed stoichiometry at ligand saturation was 1:1. Analyzing the binding mode and the reaction stoichiometry allowed us to conclude that the leptin receptor dimerization is not induced by ligand binding. This contradicts the common paradigm of cytokine receptor activation. Furthermore, data demonstrated a high-affinity interaction. The KD was 0.23+/-0.08 nM, with ka = (1.9 +/- 0.4) x 10(6) M(-1)s(-1) and kd = (4.4 +/- 0.6) x 10(-4) s(-1) for human leptin with its cognate receptor. Similar results were observed for the affinity of different species of leptin binding to mouse leptin receptor.
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Affiliation(s)
- P Mistrík
- Division of Biochemistry and Molecular Biology, IBLS, Wolfson Building, Level 2, University of Glasgow, Glasgow G12 8QQ, UK
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35
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Jacob C, Leport M, Szilagyi C, Allen JM, Bertrand C, Lagente V. DMSO-treated HL60 cells: a model of neutrophil-like cells mainly expressing PDE4B subtype. Int Immunopharmacol 2002; 2:1647-56. [PMID: 12469939 DOI: 10.1016/s1567-5769(02)00141-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [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: 11/29/2022]
Abstract
The human promyelocytic HL60 cells acquired a neutrophilic phenotype after a 7- to 10-day DMSO treatment. Fc gammaRII was up-regulated. Fc gammaRI was also up-regulated by an additional IFN-gamma treatment. These cells are able to produce O2*- by NADPH oxidase activation in the presence of immune complexes or phorbol-12-myristate-13-acetate (PMA). A change of their PDE4 subtype profile was also observed: PDE4B was the predominant isoenzyme, PDE4D was down-regulated and PDE4A was no longer detectable. Additionally, the more NADPH oxidase was activated by PMA, the less PDE4A was expressed, suggesting that NADPH oxidase activity could be used as a surrogate marker of PDE4A down-regulation. Rolipram and Ariflo (cilomilast), two selective PDE4 inhibitors, dose-dependently inhibited receptor-coupled activation of superoxide. These results suggest that PDE4B is the main subtype involved in regulating superoxide induced by Fc gammaRs activation. Furthermore, these cells, expressing almost exclusively PDE4B subtype, could be useful to identify selective PDE4B inhibitors.
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Affiliation(s)
- C Jacob
- Fresnes Laboratories, Department of Biology, Pfizer Global R&D, 3-9, rue de la Loge, 94265 Fresnes, France.
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Melendez AJ, Bruetschy L, Floto RA, Harnett MM, Allen JM. Functional coupling of FcgammaRI to nicotinamide adenine dinucleotide phosphate (reduced form) oxidative burst and immune complex trafficking requires the activation of phospholipase D1. Blood 2001; 98:3421-8. [PMID: 11719383 DOI: 10.1182/blood.v98.12.3421] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immunoglobulin G (IgG) receptors (FcgammaRs) on myeloid cells are responsible for the internalization of immune complexes. Activation of the oxidase burst is an important component of the integrated cellular response mediated by Fc receptors. Previous work has demonstrated that, in interferon-gamma-primed U937 cells, the high-affinity receptor for IgG, FcgammaRI, is coupled to a novel intracellular signaling pathway that involves the sequential activation of phospholipase D (PLD), sphingosine kinase, and calcium transients. Here, it is shown that both known PLD isozymes, PLD1 and PLD2, were present in these cells. With the use of antisense oligonucleotides to specifically reduce the expression of either isozyme, PLD1, but not PLD2, was found to be coupled to FcgammaRI activation and be required to mediate receptor activation of sphingosine kinase and calcium transients. In addition, coupling of FcgammaRI to activation of the nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH) oxidase burst was inhibited by pretreating cells with 0.3% butan-1-ol, indicating an absolute requirement for PLD. Furthermore, use of antisense oligonucleotides to reduce expression of PLD1 or PLD2 demonstrated that PLD1 is required to couple FcgammaRI to the activation of NADPH oxidase and trafficking of internalized immune complexes for degradation. These studies demonstrate the critical role of PLD1 in the intracellular signaling cascades initiated by FcgammaRI and its functional role in coordinating the response to antigen-antibody complexes.
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Affiliation(s)
- A J Melendez
- Department of Molecular and Cellular Biology, Pfizer Global Research and Development, Fresnes, France
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37
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Allen JM, Brennessel WW, Buss CE, Ellis JE, Minyaev ME, Pink M, Warnock GF, Winzenburg ML, Young VG. Synthesis, isolation, and characterization of trisodium tricarbonyliridate (3-), Na3[Ir(CO)3]. Initial studies on its derivative chemistry and structural characterizations of trans-[Ir(CO)3(EPh3)2](-), E = Ge, Sn, and trans-[Co(CO)3(SnPh3)2](-1). Inorg Chem 2001; 40:5279-84. [PMID: 11559092 DOI: 10.1021/ic0105011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Reduction of Na[Ir(CO)4] by sodium metal in (Me2N)3PO, followed by treatment with liquid ammonia, provided high yields (ca. 90%) of unsolvated Na3[Ir(CO)3], a thermally stable, pyrophoric orange solid. This substance contains iridium in its lowest known formal oxidation state of -3 and has been characterized by IR spectroscopy, elemental analyses, and derivative chemistry, i.e., by its conversion to the triphenylgermyl and triphenylstannyl complexes, trans-[Ir(CO)3(EPh3)2](-), E = Ge, Sn. Single-crystal X-ray structures of the tetraethylammonium salts of these species, as well as [Co(CO)3(SnPh3)2](-), confirm the trigonal bipyramidal nature of the anions, originally predicted on the basis of their IR spectra in the carbonyl stretching frequency region. These structural characterizations provide important additional evidence for the presence of metal tricarbonyl units in Na3[M(CO)3], M = Co, Ir.
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Affiliation(s)
- J M Allen
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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38
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Abstract
Aggregation of the human high-affinity receptor for immunoglobulin G, FcgammaRI, results in initiation of intracellular signaling cascades. However, as the receptor contains no known signaling motif, it is required to recruit an accessory molecule. The gamma chain has been proposed to fulfil this role. Here, we show that in U937 cells differentiated to a more macrophage-like phenotype with dibutyryl cAMP, FcgammaRI no longer signals through the gamma chain but rather uses FcgammaRIIa to initiate tyrosine phosphorylation. Expression of the gamma chain is, however, increased in the dbcAMP-induced cells, but here the gamma chain specifically associates with the IgA receptor, FcalphaRI. Recruitment of the gamma chain either by FcgammaRI in cytokine-primed cells or by FcalphaRI in dbcAMP-induced cells couples ligand binding to the activation of phosphatidyl choline-specific phospholipase D.
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Affiliation(s)
- A J Cameron
- Department of Medicine & Therapeutics and Division of Biochemistry & Molecular Biology, University of Glasgow, Glasgow, GB
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39
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Halbert CL, Allen JM, Miller AD. Adeno-associated virus type 6 (AAV6) vectors mediate efficient transduction of airway epithelial cells in mouse lungs compared to that of AAV2 vectors. J Virol 2001; 75:6615-24. [PMID: 11413329 PMCID: PMC114385 DOI: 10.1128/jvi.75.14.6615-6624.2001] [Citation(s) in RCA: 231] [Impact Index Per Article: 10.0] [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: 11/20/2022] Open
Abstract
Although vectors derived from adeno-associated virus type 2 (AAV2) promote gene transfer and expression in many somatic tissues, studies with animal models and cultured cells show that the apical surface of airway epithelia is resistant to transduction by AAV2 vectors. Approaches to increase transduction rates include increasing the amount of vector and perturbing the integrity of the epithelia. In this study, we explored the use of vectors based on AAV6 to increase transduction rates in airways. AAV vectors were made using combinations of rep, cap, and packaged genomes from AAV2 or AAV6. The packaged genomes encoded human placental alkaline phosphatase and contained terminal repeat sequences from AAV2 or AAV6. We found that transduction efficiency was primarily dependent on the source of Cap protein, defined here as the vector pseudotype. The AAV6 and AAV2 pseudotype vectors exhibited different tropisms in tissue-cultured cells, and cell transduction by AAV6 vectors was not inhibited by heparin, nor did they compete for entry in a transduction assay, indicating that AAV6 and AAV2 capsid bind different receptors. In vivo analysis of vectors showed that AAV2 pseudotype vectors gave high transduction rates in alveolar cells but much lower rates in the airway epithelium. In contrast, the AAV6 pseudotype vectors exhibited much more efficient transduction of epithelial cells in large and small airways, showing up to 80% transduction in some airways. These results, combined with our previous results showing lower immunogenicity of AAV6 than of AAV2 vectors, indicate that AAV6 vectors may provide significant advantages over AAV2 for gene therapy of lung diseases like cystic fibrosis.
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Affiliation(s)
- C L Halbert
- Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
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40
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Landells LJ, Szilagy CM, Jones NA, Banner KH, Allen JM, Doherty A, O'Connor BJ, Spina D, Page CP. Identification and quantification of phosphodiesterase 4 subtypes in CD4 and CD8 lymphocytes from healthy and asthmatic subjects. Br J Pharmacol 2001; 133:722-9. [PMID: 11429397 PMCID: PMC1572832 DOI: 10.1038/sj.bjp.0704120] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In the present study, for the first time, PDE4 subtypes were identified and semi-quantified in both CD4 and CD8 lymphocytes from healthy and asthmatic individuals. CD4 and CD8 lymphocytes from healthy and mild asymptomatic asthmatic subjects (receiving beta-agonist therapy only) were isolated from peripheral venous blood using appropriate antibody coated paramagnetic beads. PDE4 subtypes and beta-actin were identified by digoxigenin (DIG)-labelling reverse transcriptase-polymerase chain reaction and semi-quantified by DIG-detection enzyme-linked immunosorbance assay. In CD4 and CD8 lymphocytes PDE4A, PDE4B and PDE4D were detected, with no significant differences observed between healthy and asthmatic groups. In CD8 lymphocytes, enzyme subtype expression was lower and showed more intersubject variability. In functional studies investigating the effects of various PDE inhibitors on PHA-induced proliferation of mononuclear cells from healthy and asthmatic subjects, CDP840 (0.03 - 10 microM), rolipram (0.1 - 10 microM) and theophylline (10 microM - 1 mM) inhibited PHA-induced proliferation of mononuclear cells from healthy and asthmatic subjects in a concentration-dependent manner, although no significant difference was observed between the groups investigated. In additional studies, total monocyte cyclic AMP PDE activity was investigated in cells isolated from asthmatic subjects both prior to and 24 h after allergen challenge. Total monocyte cyclic AMP PDE activity remained unaffected following challenge of asthmatic subjects with either house dust mite or cat dander and was inhibited in a concentration-dependent manner by rolipram (0.01 - 100 microM) both before and after allergen challenge.
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Affiliation(s)
- L J Landells
- Sackler Institute of Pulmonary Pharmacology, Division of Pharmacology and Therapeutics, King's College London, 5th Floor, Hodgkin Building, Guy's Campus, London SE1 9RT
| | - C M Szilagy
- Pfizer Global Research and Development, 3–9 Rue de la Loge, BP 100, 94265 Fresnes, France
| | - N A Jones
- Sackler Institute of Pulmonary Pharmacology, Division of Pharmacology and Therapeutics, King's College London, 5th Floor, Hodgkin Building, Guy's Campus, London SE1 9RT
| | - K H Banner
- Discovery Biology, Pfizer Ltd, Ramsgate Road, Sandwich, Kent CT13 9NJ
| | - J M Allen
- Pfizer Global Research and Development, 3–9 Rue de la Loge, BP 100, 94265 Fresnes, France
| | - A Doherty
- Pfizer Global Research and Development, 3–9 Rue de la Loge, BP 100, 94265 Fresnes, France
| | - B J O'Connor
- Department of Respiratory Medicine and Allergy, GKT School of Medicine, King's College London, Bessemer Road, London SE5 9PJ
| | - D Spina
- Department of Respiratory Medicine and Allergy, GKT School of Medicine, King's College London, Bessemer Road, London SE5 9PJ
| | - C P Page
- Sackler Institute of Pulmonary Pharmacology, Division of Pharmacology and Therapeutics, King's College London, 5th Floor, Hodgkin Building, Guy's Campus, London SE1 9RT
- Author for correspondence:
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Abstract
The Y1 receptor for neuropeptide Y (NPY-Y1) is constitutively expressed in PC12 cells. In this study, we examined the role of nerve growth factor (NGF), pituitary adenylyl cyclase activating polypeptide (PACAP) and dexamethasone on the expression of the gene encoding the rat NPY-Y1 receptor in PC12 cells. A fusion gene (pY1-Luc) was constructed where the reporter enzyme firefly luciferase was placed under the control of 700 bp of the promoter region of the rat NPY-Y1 receptor gene. This promoter region contains recognition consensus sequences for various transcription factors, including one activation protein-1 (AP-1) site, two cyclic AMP responsive element sites, one estrogen receptor element site and four glucocorticoid receptor element sites. NGF increased luciferase activity in a concentration dependent manner. This increase was inhibited by K-252a, a trk A receptor inhibitor, and calphostin C, a PKC inhibitor. PACAP-38 increased luciferase activity in a concentration dependent manner. This activation was inhibited by H-89. Dexamethasone increased transcription of NPY-Y1 gene in PC12 cells. These results indicate that differentiation of PC12 cells into endocrine-like phenotype by dexamethasone and into a neuronal-like phenotype by either NGF or PACAP-38 increases the transcriptional activity of the NPY-Y1 receptor gene in PC12 cells.
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Affiliation(s)
- J C Bournat
- Division of Biochemistry and Molecular Biology and Department of Medicine and Therapeutics, University of Glasgow, G12 8QQ, Glasgow, UK
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42
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Abstract
Fc receptors play a pivotal role linking the cellular and humoral arms of the immune system [1-3]. Our previous studies have shown that the human high-affinity immunoglobulin G receptor Fc(gamma)RI couples to a novel intracellular signaling pathway requiring phospholipase D activation [4]. The mechanisms that regulate receptor coupling to phospholipase D in intact cells are poorly understood but involve small molecular weight GTPases and protein kinase C [5-7]. Here, we show that immune complex aggregation of Fc(gamma)RI stimulates the association of phospholipase D1 with ARF6 and protein kinase Calpha. Surprisingly, PKCalpha activity per se is not required. Rather, all of the Fc(gamma)RI-mediated increase in PKC activity requires phospholipase D1, as treatment of cells with butan-1-ol (0.3%) or specific downregulation of phospholipase D1 using antisense oligonucleotides inhibits Fc(gamma)RI-coupled PKC activation. Moreover, treatment of cells with butan-1-ol or phospholipase D1 antisense oligonucleotides inhibits translocation of PKCdelta, -epsilon, and -zeta but had no effect on the association of PKCalpha or ARF6 with phospholipase D1. These data indicate that association with ARF6 and PKCalpha plays a role in coupling Fc(gamma)RI to phospholipase D1 activation and that PLD1 lies upstream of all Fc(gamma)RI-mediated PKC activity.
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Affiliation(s)
- A J Melendez
- Department of Molecular and Cellular Biology, Pfizer Global Research and Development, 3-9 Rue de La Loge, 94265, Fresnes Cedex, France
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Summersgill KF, Smith EM, Levy BT, Allen JM, Haugen TH, Turek LP. Human papillomavirus in the oral cavities of children and adolescents. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001; 91:62-9. [PMID: 11174573 DOI: 10.1067/moe.2001.108797] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE The purpose of this pilot study was to determine the frequency of human papillomavirus (HPV) in the oral cavities of children and adolescents and to identify potential risk factors for HPV infection. STUDY DESIGN Sociodemographic information was obtained on 268 healthy infants, children, and adolescents who were < or = 20 years old. Oral squamous cells were collected from swabs with young children and from oral saline solution rinses with older children and adolescents. Extracted DNA was evaluated for HPV by polymerase chain reaction, dot blot hybridization, and DNA sequencing. Factors associated with the presence of HPV were tested by using chi(2), Fisher's exact test, and logistic regression tests. RESULTS HPV was detected in 6.0% of the participants. HPV frequency among young children (<7 years old) was 8.7% (11/127), and among adolescents (13-20 years old) it was 5.2% (5/97). HPV was not detected in children aged 7 to 12 years old (0/44). Fifty-four percent (6/11) of HPV-positive children were 1 year of age or less; 3 of the HPV-positive children (<7 years old) were delivered by cesarean section. No statistically significant association was found between the detection of HPV in the oral cavity and method of delivery or gender; parent's race, education, HPV-related conditions, smoking history, or number of sex partners; or adolescent's smoking history or history of sexual activity. CONCLUSIONS This study suggests that HPV is present in the oral cavity primarily in children 2 years old and younger and in adolescents 13 years and older. Cesarean delivery was not protective against oral HPV infection; in fact, half of the HPV-positive infants were born by cesarean delivery.
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Affiliation(s)
- K F Summersgill
- Veterans Affairs Medical Center, and Department of Oral Pathology, Radiology, and Medicine, University of Iowa College of Dentistry, Iowa City, USA.
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44
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Abstract
We report the development of a new 'photochemical titration' actinometric method for measurement of UV-B (290-320 nm) and UV-A (320-400 nm) light dose during drug photostability testing. It is based upon photolysis of aqueous 2-nitrobenzaldehyde solution, a well-characterized reaction that has been previously demonstrated to be useful as an accurate and reliable actinometric method. Our new method can be performed by a chemical technician using only common reagents. It has been developed for use with xenon arc lamp illumination chambers which are commonly employed for drug photostability testing, but can be readily modified for use with the other illumination sources.
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Affiliation(s)
- J M Allen
- Department of Chemistry, Indiana State University, Terre Haute, IN 47809, USA.
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45
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Weiss DJ, Bonneau L, Allen JM, Miller AD, Halbert CL. Perfluorochemical liquid enhances adeno-associated virus-mediated transgene expression in lungs. Mol Ther 2000; 2:624-30. [PMID: 11124064 DOI: 10.1006/mthe.2000.0207] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [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: 11/22/2022] Open
Abstract
Use of adeno-associated virus (AAV) vectors for lung gene therapy is limited, in part, by low levels of AAV-mediated transgene expression in lungs. Generally, less than 1% of total airway and alveolar epithelial cells express transgene activity following vector administration. A means of improving AAV vector delivery could potentially enhance AAV-mediated gene expression in lungs. We have previously demonstrated that use of perfluorochemical (PFC) liquids improved overall levels of adenovirus vector-mediated gene expression as well as distribution of expression in lungs of spontaneously breathing rodents. To evaluate whether use of PFC liquids might similarly enhance AAV-mediated expression, spontaneously breathing rodents received intratracheal instillation of the AAV vectors CWRAP and ARAP4 (2-5 x 10(8) FFU/animal) with or without 10 cc/kg body wt PFC liquid (FC-75, ACROS). Animals were sacrificed 4 weeks later and lungs assessed for overall and in situ alkaline phosphatase (AP) expression. Animals receiving vector alone exhibited scattered sparse in situ activity, predominantly in alveolar epithelium. In contrast, animals receiving vector with FC-75 exhibited increased and more widespread AP expression as well as up to a 26-fold increase in AP activity. These results demonstrate that use of the PFC liquid FC-75 improves overall and in situ AAV-mediated gene expression in rodent lungs.
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Affiliation(s)
- D J Weiss
- Division of Pulmonary and Critical Care Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
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46
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Abstract
Aggregation by immune complexes of receptors specific for the Fc region of IgG results in their internalisation and disposal by trafficking to lysosomes. We show here that internalisation of FcgammaRI by IFN-gamma treated U937 cells following receptor aggregation by cross-linking antibodies requires the activation of two distinct signalling pathways. The pathways were functionally dissected in streptolysin-O-permeabilised cells by capitalising on their relative dependence on active GTP binding proteins. One pathway required the presence of GTP-gammaS or active betagamma subunits, the other did not. Use of inhibitors revealed that the betagamma-independent pathway required activation of PI 3-kinases and was PKC-independent In contrast, the betagamma-dependent pathway involved activation of phospholipase C-beta and PKC, but was PI 3-kinase-independent. Both these pathways were found to be active in intact cells and are likely to determine receptor trafficking following internalisation.
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Affiliation(s)
- J C Norman
- Department of Biochemistry, University of Leicester, UK.
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47
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Abstract
This qualitative study examined the experience of pet ownership in the everyday lives of seven men with human immuno-deficiency virus or acquired immune deficiency syndrome. Interviews and field observations were analyzed using a grounded theory approach. The findings demonstrate that the experience of pet ownership is both typical of any pet owner and yet profoundly impacted by the illness of the owners. The results of this preliminary study indicate pet ownership can be a highly valued occupation for some, and thus has implications for occupational therapy intervention.
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Affiliation(s)
- J M Allen
- Northridge Hospital Medical Center, 18300 Roscoe Boulevard, Northridge, California 91328, USA.
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48
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Abstract
OBJECTIVE To investigate the hypoalgesic effect of true and sham acupuncture upon experimentally induced ischemic pain. DESIGN Human volunteers (n = 60) were required to attend two sessions for pain induction using a submaximal effort tourniquet technique; on the first occasion, baseline pain scores were recorded and on the second, 48 hours later, subjects were randomly allocated to one of five groups: Control, Treatment Groups 1 or 2, or Placebo Groups 1 or 2. SUBJECTS Healthy human volunteers. INTERVENTION In all the Treatment and Placebo Groups, subjects received some form of needle acupuncture 15 minutes before, and 5 minutes during, the pain induction procedure on the second day. Treatment Group 1 received acupuncture on acupuncture points situated distal to the tourniquet, whereas Treatment Group 2 received acupuncture on acupuncture points situated proximal to the tourniquet. In Placebo Groups 1 and 2, subjects received 'sham' acupuncture either on nonacupuncture points (Placebo Group 1) or on acupuncture points (Placebo Group 2) using (standardized) minimal levels of stimulation. A licensed acupuncturist who was not involved in data collection and analyses carried out all treatments. OUTCOME MEASURES Pain was assessed using a computerized visual analog scale (VAS) and a McGill Pain Questionnaire (MPQ). RESULTS Analysis of VAS scores using ANOVA revealed no significant differences between groups (e.g., VAS sum of differences data (mean +/- SEM): Treatment Group 1: 90+/-47, Treatment Group 2: 187+/-56, Placebo Group 1: 152+/-40, Placebo Group 2: 121+/-42, CONTROLS: 46+/-24, p>0.05). Analysis of MPQ percentage difference scores using one-way ANOVA revealed some isolated effects in the subjective descriptors and the Pain Rating Index, both for Treatment Group 2 and Placebo Group 2, proving them superior to any of the other groups. CONCLUSION The results of the study provide no convincing evidence for a superior hypoalgesic effect of acupuncture compared with "sham" procedures on this model of experimental pain.
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Affiliation(s)
- P Barlas
- School of Health and Social Sciences, Coventry University, United Kingdom.
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49
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Abstract
BACKGROUND AND OBJECTIVE To investigate the effect of pulsed low-intensity laser irradiation on nerve conduction in the human superficial radial nerve and on temperature in the skin overlying the nerve. STUDY DESIGN/MATERIALS AND METHODS Thirty-two healthy human volunteers were recruited and randomly assigned to either placebo, laser 1 (9.12 Hz), laser 2 (73 Hz), or control groups (n = 8 all groups). A GaAlAs laser diode (820 nm, 50 mW peak) was used to irradiate the skin overlying the right superficial radial nerve at three points (1.2 J per point; energy density, 9.55 J/cm(2)). Antidromic action potentials were recorded from the superficial radial nerve preirradiation and at 5, 10, and 15 minutes after irradiation. Skin temperature was monitored concomitantly by using two surface thermistor probes attached to the skin overlying the nerve. RESULTS Repeated measures analysis of variance showed no significant differences between groups for negative peak latency nor skin temperature data after laser irradiation. CONCLUSION This study has demonstrated that laser irradiation at the radiant exposure and pulsing parameters indicated did not produce any specific neurophysiologic effects in this model of nerve function.
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Affiliation(s)
- D M Walsh
- Rehabilitation Sciences Research Group, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim BT37 0QB, Northern Ireland.
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50
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Abstract
The current study, for which ethical approval was obtained, was designed to assess the extent to which the tenderness or mechanical allodynia observed in delayed onset muscle soreness (DOMS) might be mediated by large diameter myelinated nerve fibres. Healthy human volunteers were recruited and randomly allocated to one of three groups: Normal-Control, Ischaemic-Control, and Test-DOMS (total n=21; n=7 in each group). In the Normal-Control group, subjects attended on a single occasion for assessment of mechanical pain threshold (MPT) at standardized sites over the biceps brachii using a pressure algometer for a period of 20 min. In both remaining groups, ischaemia was induced in subjects' non-dominant upper limbs by elevation of the limb, followed by application of a sphygmomanometer cuff at a pressure of 250 mmHg. Throughout the period of the block (20-40 min), sharp/blunt sensation was assessed at regular intervals. MPT was assessed upon inflation of the cuff and reassessed at 10 min intervals until deflation. In the two ischaemic block groups, current level of pain was also monitored using a computerized visual analogue scale (VAS) at the beginning and end of the procedure. Subjects in the Test-DOMS group attended 48 h prior to ischaemic block for induction of DOMS using a standardized regime of eccentric exercise, but thereafter were treated in exactly the same manner as the Ischaemic-Control group. Results showed a significant (P<0.05; ANOVA) increase in MPT in the Test-DOMS group by the 20 min point, corresponding to a 'normalization' of MPT; loss of the ability to distinguish between sharp/blunt sensation accompanied such changes. Parallel increases in reported pain were seen in both groups undergoing ischaemic block, indicating that the procedure did not alter nociception. While not definitive, these results suggest that altered processing of activity in large diameter (myelinated) afferents might underlie the mechanical allodynia observed in DOMS; thus, this is an area which warrants further investigation.
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Affiliation(s)
- P Barlas
- Rehabilitation Sciences Research Group, University of Ulster, Jordanstown, Co. Antrim, BT37 0QB, UK
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