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Cotton S, McHugh MP, Dewar R, Haas JG, Templeton K. Investigation of hospital discharge cases and SARS-CoV-2 introduction into Lothian care homes. J Hosp Infect 2023; 135:28-36. [PMID: 36906180 PMCID: PMC9997060 DOI: 10.1016/j.jhin.2023.02.010] [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: 12/09/2022] [Revised: 02/09/2023] [Accepted: 02/12/2023] [Indexed: 03/13/2023]
Abstract
BACKGROUND The first epidemic wave of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Scotland resulted in high case numbers and mortality in care homes. In Lothian, over a third of care homes reported an outbreak while there was limited testing of hospital patients discharged to care homes. AIM Investigate hospital discharges as a source of SARS-CoV-2 introduction into care homes during the first epidemic wave. METHODS A clinical review was performed for all discharges from hospitals to care homes starting 1st March 2020 to 31st May 2020. Episodes were ruled out based on coronavirus disease (COVID-19) test history, clinical assessment at discharge, whole genome sequencing (WGS) data and an infectious period of 14 days. Clinical samples were processed for WGS, and consensus genomes generated were used for analysis by cluster investigation and virus epidemiological tool (CIVET). Patient timelines were obtained using electronic hospital records. FINDINGS In total 787 hospital discharges to care homes were identified. Out of these 776 (99%) were ruled out for hospital discharge introduction. However, for 10 episodes the results were inconclusive as there was low genomic diversity in consensus genomes or no sequencing data. Only one discharge episode had a genomic, time and location link to positive cases during hospital admission leading to 10 further positive cases in the care home. CONCLUSION Majority of hospital discharges were ruled out for introduction into Lothian care homes highlighting the importance of screening all new admissions when faced with a novel emerging virus and no vaccine available.
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Affiliation(s)
- S Cotton
- Specialist Virology Centre, Royal Infirmary Edinburgh, NHS Lothian, UK; Infection Medicine, Edinburgh Medical School, University of Edinburgh, UK.
| | - M P McHugh
- Specialist Virology Centre, Royal Infirmary Edinburgh, NHS Lothian, UK; School of Medicine, University of St Andrews, UK
| | - R Dewar
- Specialist Virology Centre, Royal Infirmary Edinburgh, NHS Lothian, UK
| | - J G Haas
- Specialist Virology Centre, Royal Infirmary Edinburgh, NHS Lothian, UK; Infection Medicine, Edinburgh Medical School, University of Edinburgh, UK
| | - K Templeton
- Specialist Virology Centre, Royal Infirmary Edinburgh, NHS Lothian, UK; Infection Medicine, Edinburgh Medical School, University of Edinburgh, UK
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Kohonen KM, Dewar R, Tramontana G, Mauranen A, Kolari P, Kooijmans LMJ, Papale D, Vesala T, Mammarella I. Intercomparison of methods to estimate gross primary production based on CO 2 and COS flux measurements. Biogeosciences 2022; 19:4067-4088. [PMID: 36171741 PMCID: PMC7613647 DOI: 10.5194/bg-19-4067-2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Separating the components of ecosystem-scale carbon exchange is crucial in order to develop better models and future predictions of the terrestrial carbon cycle. However, there are several uncertainties and unknowns related to current photosynthesis estimates. In this study, we evaluate four different methods for estimating photosynthesis at a boreal forest at the ecosystem scale, of which two are based on carbon dioxide (CO2) flux measurements and two on carbonyl sulfide (COS) flux measurements. The CO2-based methods use traditional flux partitioning and artificial neural networks to separate the net CO2 flux into respiration and photosynthesis. The COS-based methods make use of a unique 5-year COS flux data set and involve two different approaches to determine the leaf-scale relative uptake ratio of COS and CO2 (LRU), of which one (LRUCAP) was developed in this study. LRUCAP was based on a previously tested stomatal optimization theory (CAP), while LRUPAR was based on an empirical relation to measured radiation. For the measurement period 2013-2017, the artificial neural network method gave a GPP estimate very close to that of traditional flux partitioning at all timescales. On average, the COS-based methods gave higher GPP estimates than the CO2-based estimates on daily (23% and 7% higher, using LRUPAR and LRUCAP, respectively) and monthly scales (20% and 3% higher), as well as a higher cumulative sum over 3 months in all years (on average 25% and 3% higher). LRUCAP was higher than LRU estimated from chamber measurements at high radiation, leading to underestimation of midday GPP relative to other GPP methods. In general, however, use of LRUCAP gave closer agreement with CO2-based estimates of GPP than use of LRUPAR. When extended to other sites, LRUCAP may be more robust than LRUPAR because it is based on a physiological model whose parameters can be estimated from simple measurements or obtained from the literature. In contrast, the empirical radiation relation in LRUPAR may be more site-specific. However, this requires further testing at other measurement sites.
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Affiliation(s)
- Kukka-Maaria Kohonen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
| | - Roderick Dewar
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Gianluca Tramontana
- Image Processing Laboratory (IPL), Parc Científic Universitat de València, Universitat de València, Paterna, Spain
- Terrasystem s.r.l, Viterbo, Italy
| | - Aleksanteri Mauranen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
| | - Pasi Kolari
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
| | - Linda M. J. Kooijmans
- Meteorology and Air Quality, Wageningen University and Research, Wageningen, the Netherlands
| | - Dario Papale
- DIBAF, Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, Viterbo, Italy
- IAFES, Euro-Mediterranean Center for Climate Change (CMCC), Viterbo, Italy
| | - Timo Vesala
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Ivan Mammarella
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
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Dewar R, Hölttä T, Salmon Y. Exploring optimal stomatal control under alternative hypotheses for the regulation of plant sources and sinks. New Phytol 2022; 233:639-654. [PMID: 34637543 DOI: 10.1111/nph.17795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
Experimental evidence that nonstomatal limitations to photosynthesis (NSLs) correlate with leaf sugar and/or leaf water status suggests the possibility that stomata adjust to maximise photosynthesis through a trade-off between leaf CO2 supply and NSLs, potentially involving source-sink interactions. However, the mechanisms regulating NSLs and sink strength, as well as their implications for stomatal control, remain uncertain. We used an analytically solvable model to explore optimal stomatal control under alternative hypotheses for source and sink regulation. We assumed that either leaf sugar concentration or leaf water potential regulates NSLs, and that either phloem turgor pressure or phloem sugar concentration regulates sink phloem unloading. All hypotheses led to realistic stomatal responses to light, CO2 and air humidity, including conservative behaviour for the intercellular-to-atmospheric CO2 concentration ratio. Sugar-regulated and water-regulated NSLs are distinguished by the presence/absence of a stomatal closure response to changing sink strength. Turgor-regulated and sugar-regulated phloem unloading are distinguished by the presence/absence of stomatal closure under drought and avoidance/occurrence of negative phloem turgor. Results from girdling and drought experiments on Pinus sylvestris, Betula pendula, Populus tremula and Picea abies saplings are consistent with optimal stomatal control under sugar-regulated NSLs and turgor-regulated unloading. Our analytical results provide a simple representation of stomatal responses to above-ground and below-ground environmental factors and sink activity.
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Affiliation(s)
- Roderick Dewar
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
| | - Yann Salmon
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Latokartanonkaari 7, Helsinki, 00014, Finland
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Hill KJ, Dewar R, Templeton K. A multiregional evaluation of Ct values in SARS-CoV-2 VOC-20DEC-01 variant. J Infect Dis 2021; 224:927-928. [PMID: 34097743 DOI: 10.1093/infdis/jiab303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/04/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- K J Hill
- NHS Lothian, Infectious Diseases, Royal Infirmary EdinburghLittle France Crescent, Edinburgh, Midlothian, GB
| | - R Dewar
- NHS Lothian, Infectious Diseases, Royal Infirmary EdinburghLittle France Crescent, Edinburgh, Midlothian, GB
| | - K Templeton
- NHS Lothian, Infectious Diseases, Royal Infirmary EdinburghLittle France Crescent, Edinburgh, Midlothian, GB
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Salmon Y, Lintunen A, Dayet A, Chan T, Dewar R, Vesala T, Hölttä T. Leaf carbon and water status control stomatal and nonstomatal limitations of photosynthesis in trees. New Phytol 2020; 226:690-703. [PMID: 31955422 DOI: 10.1111/nph.16436] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/18/2019] [Indexed: 05/22/2023]
Abstract
Photosynthetic rate is concurrently limited by stomatal limitations and nonstomatal limitations (NSLs). However, the controls on NSLs to photosynthesis and their coordination with stomatal control on different timescales remain poorly understood. According to a recent optimization hypothesis, NSLs depend on leaf osmotic or water status and are coordinated with stomatal control so as to maximize leaf photosynthesis. Drought and notching experiments were conducted on Pinus sylvestris, Picea abies, Betula Pendula and Populus tremula seedlings in glasshouse conditions to study the dependence of NSLs on leaf osmotic and water status, and their coordination with stomatal control, on timescales of minutes and weeks, to test the assumptions and predictions of the optimization hypothesis. Both NSLs and stomatal conductance followed power-law functions of leaf osmotic concentration and leaf water potential. Moreover, stomatal conductance was proportional to the square root of soil-to-leaf hydraulic conductance, as predicted by the optimization hypothesis. Though the detailed mechanisms underlying the dependence of NSLs on leaf osmotic or water status lie outside the scope of this study, our results support the hypothesis that NSLs and stomatal control are coordinated to maximize leaf photosynthesis and allow the effect of NSLs to be included in models of tree gas-exchange.
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Affiliation(s)
- Yann Salmon
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, Helsinki, 00014, Finland
| | - Anna Lintunen
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, Helsinki, 00014, Finland
| | - Alexia Dayet
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, Helsinki, 00014, Finland
| | - Tommy Chan
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, Helsinki, 00014, Finland
| | - Roderick Dewar
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Timo Vesala
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, Helsinki, 00014, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, Helsinki, 00014, Finland
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, Helsinki, 00014, Finland
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Franklin O, Harrison SP, Dewar R, Farrior CE, Brännström Å, Dieckmann U, Pietsch S, Falster D, Cramer W, Loreau M, Wang H, Mäkelä A, Rebel KT, Meron E, Schymanski SJ, Rovenskaya E, Stocker BD, Zaehle S, Manzoni S, van Oijen M, Wright IJ, Ciais P, van Bodegom PM, Peñuelas J, Hofhansl F, Terrer C, Soudzilovskaia NA, Midgley G, Prentice IC. Organizing principles for vegetation dynamics. Nat Plants 2020; 6:444-453. [PMID: 32393882 DOI: 10.1038/s41477-020-0655-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Plants and vegetation play a critical-but largely unpredictable-role in global environmental changes due to the multitude of contributing processes at widely different spatial and temporal scales. In this Perspective, we explore approaches to master this complexity and improve our ability to predict vegetation dynamics by explicitly taking account of principles that constrain plant and ecosystem behaviour: natural selection, self-organization and entropy maximization. These ideas are increasingly being used in vegetation models, but we argue that their full potential has yet to be realized. We demonstrate the power of natural selection-based optimality principles to predict photosynthetic and carbon allocation responses to multiple environmental drivers, as well as how individual plasticity leads to the predictable self-organization of forest canopies. We show how models of natural selection acting on a few key traits can generate realistic plant communities and how entropy maximization can identify the most probable outcomes of community dynamics in space- and time-varying environments. Finally, we present a roadmap indicating how these principles could be combined in a new generation of models with stronger theoretical foundations and an improved capacity to predict complex vegetation responses to environmental change.
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Affiliation(s)
- Oskar Franklin
- International Institute for Applied Systems Analysis, Laxenburg, Austria.
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
| | - Sandy P Harrison
- Department of Geography and Environmental Science, University of Reading, Reading, UK
| | - Roderick Dewar
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, Australia
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | - Caroline E Farrior
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Åke Brännström
- International Institute for Applied Systems Analysis, Laxenburg, Austria
- Department of Mathematics and Mathematical Statistics, Umeå University, Umeå, Sweden
| | - Ulf Dieckmann
- International Institute for Applied Systems Analysis, Laxenburg, Austria
- Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies (Sokendai), Hayama, Japan
| | - Stephan Pietsch
- International Institute for Applied Systems Analysis, Laxenburg, Austria
| | - Daniel Falster
- Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Wolfgang Cramer
- Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale (IMBE), Aix Marseille Université, CNRS, IRD, Avignon Université, Technopôle Arbois-Méditerranée, Aix-en-Provence, France
| | - Michel Loreau
- Centre for Biodiversity, Theory, and Modelling, Theoretical and Experimental Ecology Station, CNRS, Moulis, France
| | - Han Wang
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
| | - Annikki Mäkelä
- Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Karin T Rebel
- Copernicus Institute of Sustainable Development, Environmental Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Ehud Meron
- Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Israel
- Department of Physics, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Stanislaus J Schymanski
- Department of Environmental Research and Innovation, Luxembourg Institute of Science and Technology, Esch-sur-Alzette, Luxembourg
| | - Elena Rovenskaya
- International Institute for Applied Systems Analysis, Laxenburg, Austria
| | - Benjamin D Stocker
- Department of Environmental Systems Sciences, ETH Zurich, Zurich, Switzerland
- CREAF, Cerdanyola del Vallès, Spain
| | - Sönke Zaehle
- Biogeochemical Integration Department, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Stefano Manzoni
- Department of Physical Geography, Stockholm University, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm, Sweden
| | - Marcel van Oijen
- Centre for Ecology and Hydrology (CEH-Edinburgh), Bush Estate, Penicuik, UK
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, CEA CNRS UVSQ, Gif-sur-Yvette, France
| | - Peter M van Bodegom
- Environmental Biology Department, Institute of Environmental Sciences, CML, Leiden University, Leiden, The Netherlands
| | - Josep Peñuelas
- CREAF, Cerdanyola del Vallès, Spain
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Spain
| | - Florian Hofhansl
- International Institute for Applied Systems Analysis, Laxenburg, Austria
| | - Cesar Terrer
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Nadejda A Soudzilovskaia
- Environmental Biology Department, Institute of Environmental Sciences, CML, Leiden University, Leiden, The Netherlands
| | - Guy Midgley
- Department Botany & Zoology, Stellenbosch University, Stellenbosch, South Africa
| | - I Colin Prentice
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia
- AXA Chair of Biosphere and Climate Impacts, Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, UK
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Lintunen A, Paljakka T, Salmon Y, Dewar R, Riikonen A, Hölttä T. The influence of soil temperature and water content on belowground hydraulic conductance and leaf gas exchange in mature trees of three boreal species. Plant Cell Environ 2020; 43:532-547. [PMID: 31873942 DOI: 10.1111/pce.13709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 12/16/2019] [Indexed: 06/10/2023]
Abstract
Understanding stomatal regulation is fundamental to predicting the impact of changing environmental conditions on vegetation. However, the influence of soil temperature (ST) and soil water content (SWC) on canopy conductance (gs ) through changes in belowground hydraulic conductance (kbg ) remains poorly understood, because kbg has seldom been measured in field conditions. Our aim was to (a) examine the dependence of kbg on ST and SWC, (b) examine the dependence of gs on kbg and (c) test a recent stomatal optimization model according to which gs and soil-to-leaf hydraulic conductance are strongly coupled. We estimated kbg from continuous sap flow and xylem diameter measurements in three boreal species. kbg increased strongly with increasing ST when ST was below +8°C, and typically increased with increasing SWC when ST was not limiting. gs was correlated with kbg in all three species, and modelled and measured gs were well correlated in Pinus sylvestris (a model comparison was only possible for this species). These results imply an important role for kbg in mediating linkages between the soil environment and leaf gas exchange. In particular, our finding that ST strongly influences kbg in mature trees may help us to better understand tree behaviour in cold environments.
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Affiliation(s)
- Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Teemu Paljakka
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Roderick Dewar
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, Australia
| | - Anu Riikonen
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
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Dewar R, Mauranen A, Mäkelä A, Hölttä T, Medlyn B, Vesala T. New insights into the covariation of stomatal, mesophyll and hydraulic conductances from optimization models incorporating nonstomatal limitations to photosynthesis. New Phytol 2018; 217:571-585. [PMID: 29086921 DOI: 10.1111/nph.14848] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/10/2017] [Indexed: 05/08/2023]
Abstract
Optimization models of stomatal conductance (gs ) attempt to explain observed stomatal behaviour in terms of cost--benefit tradeoffs. While the benefit of stomatal opening through increased CO2 uptake is clear, currently the nature of the associated cost(s) remains unclear. We explored the hypothesis that gs maximizes leaf photosynthesis, where the cost of stomatal opening arises from nonstomatal reductions in photosynthesis induced by leaf water stress. We analytically solved two cases, CAP and MES, in which reduced leaf water potential leads to reductions in carboxylation capacity (CAP) and mesophyll conductance (gm ) (MES). Both CAP and MES predict the same one-parameter relationship between the intercellular : atmospheric CO2 concentration ratio (ci /ca ) and vapour pressure deficit (VPD, D), viz. ci /ca ≈ ξ/(ξ + √D), as that obtained from previous optimization models, with the novel feature that the parameter ξ is determined unambiguously as a function of a small number of photosynthetic and hydraulic variables. These include soil-to-leaf hydraulic conductance, implying a stomatal closure response to drought. MES also predicts that gs /gm is closely related to ci /ca and is similarly conservative. These results are consistent with observations, give rise to new testable predictions, and offer new insights into the covariation of stomatal, mesophyll and hydraulic conductances.
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Affiliation(s)
- Roderick Dewar
- Plant Sciences Division, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Aleksanteri Mauranen
- Department of Physics, University of Helsinki, PO Box 68, Helsinki, FI-00014, Finland
| | - Annikki Mäkelä
- Department of Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
| | - Teemu Hölttä
- Department of Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
| | - Belinda Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Timo Vesala
- Department of Physics, University of Helsinki, PO Box 68, Helsinki, FI-00014, Finland
- Department of Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
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Dewar R, Claus AP, Tucker K, Ware R, Johnston LM. Reproducibility of the Balance Evaluation Systems Test (BESTest) and the Mini-BESTest in school-aged children. Gait Posture 2017; 55:68-74. [PMID: 28419876 DOI: 10.1016/j.gaitpost.2017.04.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [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: 10/26/2016] [Revised: 04/03/2017] [Accepted: 04/05/2017] [Indexed: 02/02/2023]
Abstract
This study evaluated the intra-rater, inter-rater and test-retest reproducibility of the Full-BESTest and Mini-BESTest when assessing postural control in children. Thirty-four children aged 7-17 years participated in intra-rater and inter-rater evaluation, and 22 children repeated assessment six weeks later for evaluation of test-retest reliability. Postural control was assessed using the Full Balance Evaluation Systems Test (Full-BESTest) and the short-form Mini-BESTest. Intra-rater, inter-rater and test-retest reproducibility were examined using video assessment. Test-retest reproducibility was also assessed in real-time. Reproducibility was examined by agreement and reliability statistics. Agreement was calculated using percentage of agreement, Limits of Agreement and Smallest Detectable Change. Reliability was calculated using Intra-class Correlation Coefficients. Results showed that the reliability of Total Scores was excellent for the Full-BESTest for all conditions (all ICCs>0.82), whereas the Mini-BESTest ranged from fair to excellent (ICC=0.56-0.86). Percentage of Domain Scores with good-excellent reliability (ICCs>0.60) was slightly higher for the Full-BESTest (66%) compared to the Mini-BESTest (59%). Smallest Detectable Change scores were good to excellent for the Full-BESTest (2%-6%) and for the Mini-BESTest (5%-10%) relative to total test scores. Both the Full-BESTest and Mini-BESTest can discriminate postural control abilities within and between days in school-aged children. The Full-BESTest has slightly better reproducibility and a broader range of items, which could be the most useful version for treatment planning. We propose minor modifications to improve reproducibility for children, and indicate the modified version by the title Kids-BESTest. Future psychometric research is recommended for specific paediatric clinical populations.
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Affiliation(s)
- R Dewar
- The University of Queensland, School of Health and Rehabilitation Sciences, Brisbane, Australia.
| | - A P Claus
- The University of Queensland, School of Health and Rehabilitation Sciences, Brisbane, Australia
| | - K Tucker
- The University of Queensland, School of Biomedical Sciences, Brisbane, Australia
| | - R Ware
- Griffith University, Menzies Health Institute Queensland, Australia; The University of Queensland, Queensland Centre for Intellectual and Developmental Disability, Brisbane, Australia
| | - L M Johnston
- The University of Queensland, School of Health and Rehabilitation Sciences, Brisbane, Australia
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Zhao Y, Bowes D, Castonguay M, Xu Z, Plourde M, Mulroy L, MacNeil M, Dewar R. Incidence of Brain Metastases and Outcomes in Pulmonary Large Cell Neuroendocrine Carcinoma. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.1696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Chadder J, Dewar R, Shack L, Nishri D, Niu J, Lockwood G. A first look at relative survival by stage for colorectal and lung cancers in Canada. ACTA ACUST UNITED AC 2016; 23:119-24. [PMID: 27122976 DOI: 10.3747/co.23.3096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Monitoring and reporting on cancer survival provides a mechanism for understanding the effectiveness of Canada's cancer care system. Although 5-year relative survival for colorectal cancer and lung cancer has been previously reported, only recently has pan-Canadian relative survival by stage been analyzed using comprehensive registry data. This article presents a first look at 2-year relative survival by stage for colorectal and lung cancer across 9 provinces. As expected, 2-year age-standardized relative survival ratios (arsrs) for colorectal cancer and lung cancer were higher when the cancer was diagnosed at an earlier stage. The arsrs for stage i colorectal cancer ranged from 92.2% in Nova Scotia [95% confidence interval (ci): 88.6% to 95.1%] to 98.4% in British Columbia (95% ci: 96.2% to 99.3%); for stage iv, they ranged from 24.3% in Prince Edward Island (95% ci: 15.2% to 34.4%) to 38.8% in New Brunswick (95% ci: 33.3% to 44.2%). The arsrs for stage i lung cancer ranged from 66.5% in Prince Edward Island (95% ci: 54.5% to 76.5%) to 84.8% in Ontario (95% ci: 83.5% to 86.0%). By contrast, arsrs for stage iv lung cancer ranged from 7.6% in Manitoba (95% ci: 5.8% to 9.7%) to 13.2% in British Columbia (95% ci: 11.8% to 14.6%). The available stage data are too recent to allow for meaningful comparisons between provinces, but over time, analyzing relative survival by stage can provide further insight into the known differences in 5-year relative survival. As the data mature, they will enable an assessment of the extent to which interprovincial differences in relative survival are influenced by differences in stage distribution or treatment effectiveness (or both), permitting targeted measures to improve population health outcomes to be implemented.
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Affiliation(s)
- J Chadder
- Canadian Partnership Against Cancer, Toronto, ON
| | - R Dewar
- Cancer Care Nova Scotia, Halifax, NS
| | - L Shack
- CancerControl Alberta, Alberta Health Services, Calgary, AB;; Departments of Community Health Sciences and of Oncology, University of Calgary, Calgary, AB
| | - D Nishri
- Cancer Care Ontario, Toronto, ON
| | - J Niu
- Canadian Partnership Against Cancer, Toronto, ON
| | - G Lockwood
- Canadian Partnership Against Cancer, Toronto, ON
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Leis A, Verhoef M, Deschamps M, Doll R, Tan L, Dewar R. What determines the use of complementary therapies by Canadian cancer patients? ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.2042-7166.2003.tb05811.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Urquhart R, Bu J, Porter GA, Dewar R, Moineddin R, Grunfeld E. Relationship between survival and lymph node assessment from a population-based study of colorectal cancer patients. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.6125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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14
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Abstract
Tumor microenvironment has a major role in cancer progression and resistance to treatment. The bone marrow (BM) is a dynamic network of growth factors, cytokines and stromal cells, providing a permissive environment for leukemogenesis and progression. Both BM stroma and leukemic blasts promote angiogenesis, which is increased in acute lymphoblastic leukemia and acute myeloid leukemia. Growth factors like vascular endothelial growth factor (VEGF), basic fibroblast growth factor and angiopoietins are the main proangiogenic mediators in acute leukemia. Autocrine proleukemic loops have been described for VEGF and angiopoietin in hematopoietic cells. Interactions of stromal cells and extracellular matrix with leukemic blasts can also generate antiapoptotic signals that contribute to neoplastic progression and persistence of treatment-resistant minimal residual disease. High expression of CXC chemokine ligand 4 (CXCR4) by leukemic blasts and activation of the CXCR4-CXCL12 axis is involved in leukemia progression and disruption of normal hematopoiesis. Leukemia-associated bone microenvironment markers could be used as prognostic or predictive indicators of disease progression and/or treatment outcome. Studies related to bone microenvironment would likely provide a better understanding of the treatment resistance associated with leukemia therapy and design of new treatments.
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Affiliation(s)
- F Ayala
- Division of Matrix Biology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 3 Blackfan Circle, Boston, MA, USA
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15
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Morzycki W, Yeung G, Husein S, Juneja N, Dewar R, Younis T, Virik K, Davis M, Bethune D, Xu Z. 549 POSTER Malignant mesothelioma (MM): prognostic risk factors and immunohistochemical markers in correlation with pathological changes and prognosis. EJC Suppl 2007. [DOI: 10.1016/s1359-6349(07)70488-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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16
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Younis T, Rayson D, Dewar R, Skedgel C. Modeling for cost-effective-adjuvant aromatase inhibitor strategies for postmenopausal women with breast cancer. Ann Oncol 2007; 18:293-8. [PMID: 17095569 DOI: 10.1093/annonc/mdl410] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND To determine cost-effective (CE) strategies comparing adjuvant upfront aromatase inhibitor (AI) with sequential tamoxifen (TAM) AI in postmenopausal (PM) women with breast cancer (BC). DESIGN A Markov model was constructed to calculate cumulative costs and quality-adjusted life year (QALY) gains for upfront AI and TAM-AI in a hypothetical cohort of 60-year-old PM women with BC. Costs, utilities and probabilities were derived from the literature. The hazard ratios (HRs) of AI strategies were applied to a baseline cancer recurrence risk (RR) to determine CE strategies at the $50,000/QALY gain threshold. A direct payer perspective is utilized, and costs and benefits were discounted at 3%. RESULTS Two-way sensitivity analyses are presented to determine CE strategies across a wide range of HRs and in different clinical scenarios including varying RRs (low, average, high and very high). TAM-AI is the preferred CE strategy at low and average RR, while upfront AI is CE at very high RR. The CE strategy in patients with high RR was dependent on the scenario examined. CONCLUSIONS This model may help health care providers select CE-adjuvant AI strategies in PM women with BC, until further direct evidence is available from randomized clinical trials.
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Affiliation(s)
- T Younis
- Department of Medicine, Dalhousie University at Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada.
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17
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Abstract
Measurement of care time intervals is complex, being influenced by many factors. The definition of the care interval monitored can also bias the detection of changes in waits. The implications of using different care interval definitions to report wait times and identify delays in care provision were examined using a retrospective chart review of 637 women with surgically treated breast cancer who were referred to a cancer centre between September 1999 and 2000 or September 2003 and 2004. Overall waits between detection and adjuvant treatment increased by 12 days over the two periods, but their exact location and cause(s) could not be determined at such a low-resolution interval. At higher resolutions of care intervals, reporting the comprehensive sequence of care events, the prolongation was mainly associated with delayed access to surgery (4 days) and delivery of adjuvant chemotherapy (4 days). The latter went unnoticed when waits were reported at intermediate (referral to adjuvant treatment) and low (detection to adjuvant treatment) resolutions. Disease stage and type of first adjuvant treatment consistently and significantly influenced the length of waits. Comprehensive monitoring of the entire care path is essential to effectively prioritize interventions, assess their outcomes and optimise access to cancer care.
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Affiliation(s)
- N Saint-Jacques
- Surveillance and Epidemiology Unit, Cancer Care Nova Scotia, QEII Health Sciences Centre, 560 Bethune Building, 1278 Tower Road, Halifax, Nova Scotia, Canada B3H 2Y9.
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18
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Skedgel C, Rayson D, Dewar R, Younis T. Cost-utility of adjuvant hormone therapies for breast cancer in post-menopausal women: sequential tamoxifen-exemestane and upfront anastrozole. Breast Cancer Res Treat 2006; 101:325-33. [PMID: 16897433 DOI: 10.1007/s10549-006-9299-4] [Citation(s) in RCA: 22] [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] [Received: 05/29/2006] [Accepted: 05/31/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Adjuvant Anastrozole (ANA) for 5 years and Tamoxifen followed by Exemestane (TAM-EXE) for 2.5 years each have become acceptable alternatives to 5 years of Tamoxifen (TAM) for post-menopausal women with breast cancer. As these newer options are associated with higher drug costs as well as improved outcomes, an economic evaluation was undertaken to compare the cost-utility of ANA and TAM-EXE relative to TAM alone and to each other in terms of cost per quality-adjusted life year (QALY) gained. METHODS A Markov model was developed to calculate monthly costs and outcomes in a hypothetical cohort of post-menopausal women with early-stage breast cancer. Baseline rates of cancer recurrence and adverse effects with TAM, and hazard ratios associated with ANA and EXE, were derived from the ATAC and IES trials. Patients received hormonal therapy for 5 years and benefit was modeled to persist 5 years beyond treatment. The analysis took a direct payer perspective with a 20-year time horizon. Costs and outcomes were discounted by 3%. Costs are in 2005 Canadian dollars. RESULTS ANA and TAM-EXE were associated with increased costs and QALYs, though the cost-utility of both relative to TAM alone was strongly favourable (<$50,000/QALY). Based on an indirect comparison of ANA and TAM-EXE, using TAM alone as a common comparator, the cost-utility of ANA relative to TAM-EXE appears unfavourable. CONCLUSIONS Both upfront and sequential AI options were cost-effective alternatives to TAM alone, but TAM-EXE appears to be the economically preferred AI option based on its more favourable cost-utility versus ANA.
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Affiliation(s)
- C Skedgel
- Department of Medicine, Centre for Clinical Research, Dalhousie University, 5790 University Ave, B3H 1V7, Halifax, NS, Canada.
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19
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Lethbridge L, Grunfeld E, Dewar R, Johnston G, McIntyre P, Lawson B, Burge F, Dent S, Paszat L, Earle C. Quality indicators for end-of-life breast cancer care: Testing the use of administrative databases. J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.6066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
6066 Background: Defining, measuring and monitoring quality of care is a facet of health services research that is growing in importance. Breast cancer offers a disease model to examine quality end-of-life (EOL) care provided to women. Administrative data have the unique potential to provide population-based measures of quality of care. The objective of this study was to assess the feasibility of using routinely-collected administrative data to measure quality EOL care for breast cancer patients. Methods: A cohort of all women in Nova Scotia who died of breast cancer between 01/01/1998 and 31/12/2002 was assembled from the Cancer Registry and Vital Statistics data. The EOL study period was defined as the last 6 months of life. A total of 864 women met the eligibility criteria. After a literature review, an expert panel identified 19 indicators that were potentially measurable through administrative data. Physician billings, hospital discharge abstracts and seniors pharmacare data, supplemented by clinical datasets, were utilized to calculate the statistics with which to represent the indicators. Results: Benchmark measures of care across the cohort show 63.4% died in a hospital, a mean continuity of care index of 0.786, and the mean number of inpatient days in the last 30 was 9.9. Indicators of aggressive care include 9.3% had chemotherapy in the last 14 days, 5.6% had more than 1 emergency room visit in the last 30 days, and 29.1% had more than 14 inpatient days in the last 30 days. Conclusions: Weaknesses of using these data include: 1) fixed variables with an administrative rather than a clinical objective; 2) lack of comprehensiveness of various datasets; and 3) the use of billings data where increasingly physicians are paid through methods other than fee-for-service. Strengths of this approach are: 1) population-based cohort; 2) comprehensiveness of cohort selection through the provincial Vital Statistics file; and 3) accessibility of data. No significant financial relationships to disclose.
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Affiliation(s)
- L. Lethbridge
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - E. Grunfeld
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - R. Dewar
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - G. Johnston
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - P. McIntyre
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - B. Lawson
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - F. Burge
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - S. Dent
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - L. Paszat
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
| | - C. Earle
- Cancer Care Nova Scotia, Halifax, NS, Canada; Dalhousie University, Halifax, NS, Canada; University of Ottawa, Ottawa, ON, Canada; University of Toronto, Toronto, ON, Canada; Harvard University, Boston, MA
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20
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Gray S, Dakin-Hache KA, Barnes PJ, Dewar R, Younis T, Rayson D. Clinical and pathological correlations in male breast cancer (MBC): Intratumoral aromatase expression (ITA) via tissue microarray (TMA). J Clin Oncol 2006. [DOI: 10.1200/jco.2006.24.18_suppl.10553] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
10553 Background: Most cases of MBC are hormone-receptor (HR) positive and there is anecdotal evidence of disease response to aromatase inhibitors in the metastatic setting. Study objectives were to (i) assess clinical-pathologic characteristics in a cohort of MBC, (ii) evaluate intratumoral aromatase expression and (iii) assess its’ prognostic impact. Methods: A retrospective chart review was conducted for all cases of MBC seen at the Nova Scotia Cancer Centre between 1985–2005. Data abstracted included disease stage, tumor grade, HR status (ER/PR), HER2-neu and ITA expression as well as dates of disease recurrence and death. Tumor blocks were incorporated into 3 TMA’s with control specimens (gynecomastia, benign breast tissue, liver). Four 1.0 mm cores were taken of each tumor. Immunohistochemistry (IHC) was performed with the following antibodies; 6F11 ER primary Ab (Ventana, USA), 1A6 PR primary Ab (Ventana, USA), TAB250 monoclonal mouse anti-HER2 (Zymed, USA), DAKO 0185 rabbit anti-human c-erbB2 (DAKO, Canada), mouse anti-human p450 aromatase Ab (Cedarlane, Canada). ITA staining intensity and distribution was compared to benign hepatic tissue and if > or = to liver was called ’strong’ while < liver was called ’weak’. The log-rank test was used for survival comparisons. Kaplan-Meyer curves were used to estimate 5year disease-free (DFS) and overall (OS) survival probabilities. Results: 54 cases were identified with median age at diagnosis of 64 (31–85 yrs). Median tumor size was 2.6 cms (0.9–8cms) and 22 (41%) had nodal metastases. 45 cases had tissue available for IHC. Of these, 40 (89%) were ER and 33 (73%) were PR positive. HER2-neu was overexpressed in 4/42 (9.5%) and 12/45 (27%) had strong ITA expression. 5 yr DFS was 71% and OS was 64%. In univariate analysis strong (vs weak) ITA expression was associated with improved 5 yr OS (92% vs 49%, p = 0.038) but not DFS (82% vs 76%, p = 0.44) rates. Conclusion: The suggestion of improved OS but not DFS for those tumors with strong ITA expression may imply that these were more responsive to hormonal therapy in the metastatic setting or had a more indolent pace of progression. It is suggested that further investigation of ITA and response to hormonal therapy in MBC is warranted. No significant financial relationships to disclose.
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Affiliation(s)
- S. Gray
- Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
| | | | - P. J. Barnes
- Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
| | - R. Dewar
- Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
| | - T. Younis
- Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
| | - D. Rayson
- Queen Elizabeth II Health Sciences Centre, Halifax, NS, Canada
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21
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Skedgel C, Rayson D, Dewar R, Younis T. A cost-utility evaluation of adjuvant hormonal options in postmenopausal women with breast cancer: A Belgian perspective. EJC Suppl 2006. [DOI: 10.1016/s1359-6349(06)80368-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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22
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Morzycki W, Husain S, Dewar R, Virik K, Davis M, Younis T. P-415 Occupational distribution, incidence and survival rates of malignant mesothelioma in Nova Scotia, Canada 1990–2002. Lung Cancer 2005. [DOI: 10.1016/s0169-5002(05)80908-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Rayson D, Meadows J, Younis T, Dewar R. Comparison of elapsed times from breast cancer detection to first adjuvant therapy in a Canadian province, 1999–2000 and 2003–2004. J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.6005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- D. Rayson
- QEII Hlth Sci Ctr, Halifax, NS, Canada
| | | | - T. Younis
- QEII Hlth Sci Ctr, Halifax, NS, Canada
| | - R. Dewar
- QEII Hlth Sci Ctr, Halifax, NS, Canada
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24
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Husain SF, Morzycki W, Dewar R, Rayson D. Mesothelioma: Incidence and survival rates in Nova Scotia, Canada 1990–2002. J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.9636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- S. F. Husain
- Dalhousie Univ, Halifax, NS, Canada; QEII Health Sciences Ctr, Halifax, NS, Canada; Nova Scotia Cancer Care, Halifax, NS, Canada
| | - W. Morzycki
- Dalhousie Univ, Halifax, NS, Canada; QEII Health Sciences Ctr, Halifax, NS, Canada; Nova Scotia Cancer Care, Halifax, NS, Canada
| | - R. Dewar
- Dalhousie Univ, Halifax, NS, Canada; QEII Health Sciences Ctr, Halifax, NS, Canada; Nova Scotia Cancer Care, Halifax, NS, Canada
| | - D. Rayson
- Dalhousie Univ, Halifax, NS, Canada; QEII Health Sciences Ctr, Halifax, NS, Canada; Nova Scotia Cancer Care, Halifax, NS, Canada
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25
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Skedgel C, Rayson D, Dewar R, Potvin K, Younis T. Economic evaluation of adjuvant hormonal options in postmenopausal women with breast cancer: Tamoxifen vs tamoxifen then exemestane vs anastrazole. J Clin Oncol 2005. [DOI: 10.1200/jco.2005.23.16_suppl.6040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- C. Skedgel
- Queen Elizabeth II Health Sciences Ctr, Halifax, NS, Canada
| | - D. Rayson
- Queen Elizabeth II Health Sciences Ctr, Halifax, NS, Canada
| | - R. Dewar
- Queen Elizabeth II Health Sciences Ctr, Halifax, NS, Canada
| | - K. Potvin
- Queen Elizabeth II Health Sciences Ctr, Halifax, NS, Canada
| | - T. Younis
- Queen Elizabeth II Health Sciences Ctr, Halifax, NS, Canada
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26
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Lipton A, Dewar R, Conte P, Zheng M. Long-term safety of zoledronic acid for the treatment of patients with breast cancer and bone metastases. EJC Suppl 2004. [DOI: 10.1016/s1359-6349(04)90899-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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27
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Dewar R. Information theory explanation of the fluctuation theorem, maximum entropy production and self-organized criticality in non-equilibrium stationary states. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/0305-4470/36/3/303] [Citation(s) in RCA: 334] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Affiliation(s)
- F Burge
- Department of Family Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
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29
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Kovacs JA, Lempicki RA, Sidorov IA, Adelsberger JW, Herpin B, Metcalf JA, Sereti I, Polis MA, Davey RT, Tavel J, Falloon J, Stevens R, Lambert L, Dewar R, Schwartzentruber DJ, Anver MR, Baseler MW, Masur H, Dimitrov DS, Lane HC. Identification of dynamically distinct subpopulations of T lymphocytes that are differentially affected by HIV. J Exp Med 2001; 194:1731-41. [PMID: 11748275 PMCID: PMC2193579 DOI: 10.1084/jem.194.12.1731] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We examined the effects of human immunodeficiency virus infection on the turnover of CD4 and CD8 T lymphocytes in 17 HIV-infected patients by 30 min in vivo pulse labeling with bromodeoxyuridine (BrdU). The percentage of labeled CD4 and CD8 T lymphocytes was initially higher in lymph nodes than in blood. Labeled cells equilibrated between the two compartments within 24 h. Based on mathematical modeling of the dynamics of BrdU-labeled cells in the blood, we identified rapidly and slowly proliferating subpopulations of CD4 and CD8 T lymphocytes. The percentage, but not the decay rate, of labeled CD4 or CD8 cells in the rapidly proliferating pool correlated significantly with plasma HIV RNA levels for both CD4 (r = 0.77, P < 0.001) and CD8 (r = 0.81, P < 0.001) T cells. In six patients there was a geometric mean decrease of greater than 2 logs in HIV levels within 2 to 6 mo after the initiation of highly active antiretroviral therapy; this was associated with a significant decrease in the percentage (but not the decay rate) of labeled cells in the rapidly proliferating pool for both CD4 (P = 0.03) and CD8 (P < 0.001) T lymphocytes. Neither plasma viral levels nor therapy had an effect on the decay rate constants or the percentage of labeled cells in the slowly proliferating pool. Monocyte production was inversely related to viral load (r = -0.56, P = 0.003) and increased with therapy (P = 0.01). These findings demonstrate that HIV does not impair CD4 T cell production but does increase CD4 and CD8 lymphocyte proliferation and death by inducing entry into a rapidly proliferating subpopulation of cells.
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Affiliation(s)
- J A Kovacs
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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30
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Jaremko J, Delorme S, Dansereau J, Labelle H, Ronsky J, Poncet P, Harder J, Dewar R, Zernicke RF. Use of Neural Networks to Correlate Spine and Rib Deformity in Scoliosis. Comput Methods Biomech Biomed Engin 2001; 3:203-213. [PMID: 11264848 DOI: 10.1080/10255840008915265] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Artificial neural networks (ANN's) recognize patterns relating input and output data in a manner analogous to the function of biological neurons. Here, we show that ANN's can predict rib deformity in scoliosis more accurately than regression analysis. ANN's and linear regression models were developed to predict rib rotation from several combinations of input spinal indices including Cobb angle, vertebral rotation, apex location and orientation of the plane of maximal curvature. ANN's averaged 60% correct predictions compared to 34% for regression analysis. This study provides evidence for the utility of artificial neural networks in scoliosis research. These data lend credence to the use of ANN's in future work on the prediction of scoliotic spinal deformity from torso surface data, which would permit assessment of scoliosis severity with minimal use of harmful X-rays.
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Affiliation(s)
- J. Jaremko
- Dept. of Surgery, University of Calgary, Calgary, AB
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Guernsey JR, Dewar R, Weerasinghe S, Kirkland S, Veugelers PJ. Incidence of cancer in Sydney and Cape Breton County, Nova Scotia 1979-1997. Can J Public Health 2000. [PMID: 10986788 DOI: 10.1007/bf03404291] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The primary purpose of this study was to assess whether Sydney, Industrial Cape Breton County excluding Sydney (ICBxS) and Cape Breton County (CBCo) residents were at increased risk for cancer compared to Nova Scotia (NS) residents over five-year periods during 1979 through 1997. Gender-stratified, age-standardized cancer incidence rates were calculated following the direct method. All-cause rates were higher for female and male residents of Sydney, ICBxS and CBCo compared to NS based upon both municipality and postal code methods of residence classification. A sensitivity analysis of residential coding yielded a high degree of consistency for all geographies except Sydney, limiting comparisons of Sydney rates with other local geographies except where consistencies were observed. The results of this ecological study support the need for further analysis of factors contributing to the increased risk for cancer in CBCo.
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Affiliation(s)
- J R Guernsey
- Department of Community Health and Epidemiology, Faculty of Medicine, Dalhousie University, Halifax, NS.
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Hatano H, Vogel S, Yoder C, Metcalf JA, Dewar R, Davey RT, Polis MA. Pre-HAART HIV burden approximates post-HAART viral levels following interruption of therapy in patients with sustained viral suppression. AIDS 2000; 14:1357-63. [PMID: 10930150 DOI: 10.1097/00002030-200007070-00008] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the relationship between the HIV viral burden in individuals prior to receiving highly-active antiretroviral therapy (HAART) and the viral burden after withdrawal of HAART. DESIGN AND SETTING Retrospective cohort study at the National Institutes of Health, Bethesda, Maryland, USA. PATIENTS Fourteen HIV-infected patients who achieved and maintained viral control on HAART who subsequently discontinued HAART. MAIN OUTCOME MEASURES Pre- and post-HAART viral loads measured from plasma or serum. RESULTS Patients achieved viral control (< 500 copies/ml) on HAART in a median 28 days (range, 15-490 days; mean, 72 days), maintained viral control for a median 661 days (range, 53-1067 days; mean, 611 days), and subsequently discontinued HAART for a median 49 days (range, 14-196 days; mean, 73 days). The median difference between the pre- and post-HAART viral loads was 0.16 log10 (range, -0.72 to 1.05 log10; mean, 0.19 log10). The median absolute difference between the pre- and post-HAART viral loads was 0.43 log10 (range, 0.06-1.05 log10; mean, 0.46 log10). Nine individuals had post-HAART values higher than pre-HAART values, five had lower values. Median duration between pre- and post-HAART viral load measurements was 1757 days (range, 117-3177 days; mean, 1756 days), or 4.8 years. CONCLUSIONS After discontinuing HAART, individuals had rebounds in their viral burdens approximating pre-HAART levels, even after a significant lapse of time approaching 5 years. Our data suggest that an intrinsic viral load set-point may exist, and that a single interruption of an effective regimen with viral suppression for almost 2 years does not significantly alter this set-point.
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Affiliation(s)
- H Hatano
- Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-1880, USA
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Guernsey JR, Dewar R, Weerasinghe S, Kirkland S, Veugelers PJ. Incidence of cancer in Sydney and Cape Breton County, Nova Scotia 1979-1997. Can J Public Health 2000; 91:285-92. [PMID: 10986788 PMCID: PMC6979912] [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] [Subscribe] [Scholar Register] [Received: 11/04/1998] [Accepted: 02/10/2000] [Indexed: 02/17/2023]
Abstract
The primary purpose of this study was to assess whether Sydney, Industrial Cape Breton County excluding Sydney (ICBxS) and Cape Breton County (CBCo) residents were at increased risk for cancer compared to Nova Scotia (NS) residents over five-year periods during 1979 through 1997. Gender-stratified, age-standardized cancer incidence rates were calculated following the direct method. All-cause rates were higher for female and male residents of Sydney, ICBxS and CBCo compared to NS based upon both municipality and postal code methods of residence classification. A sensitivity analysis of residential coding yielded a high degree of consistency for all geographies except Sydney, limiting comparisons of Sydney rates with other local geographies except where consistencies were observed. The results of this ecological study support the need for further analysis of factors contributing to the increased risk for cancer in CBCo.
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Affiliation(s)
- J R Guernsey
- Department of Community Health and Epidemiology, Faculty of Medicine, Dalhousie University, Halifax, NS.
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Davey RT, Bhat N, Yoder C, Chun TW, Metcalf JA, Dewar R, Natarajan V, Lempicki RA, Adelsberger JW, Miller KD, Kovacs JA, Polis MA, Walker RE, Falloon J, Masur H, Gee D, Baseler M, Dimitrov DS, Fauci AS, Lane HC. HIV-1 and T cell dynamics after interruption of highly active antiretroviral therapy (HAART) in patients with a history of sustained viral suppression. Proc Natl Acad Sci U S A 1999; 96:15109-14. [PMID: 10611346 PMCID: PMC24781 DOI: 10.1073/pnas.96.26.15109] [Citation(s) in RCA: 635] [Impact Index Per Article: 25.4] [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: 11/18/2022] Open
Abstract
Identifying the immunologic and virologic consequences of discontinuing antiretroviral therapy in HIV-infected patients is of major importance in developing long-term treatment strategies for patients with HIV-1 infection. We designed a trial to characterize these parameters after interruption of highly active antiretroviral therapy (HAART) in patients who had maintained prolonged viral suppression on antiretroviral drugs. Eighteen patients with CD4(+) T cell counts >/= 350 cells/microliter and viral load below the limits of detection for >/=1 year while on HAART were enrolled prospectively in a trial in which HAART was discontinued. Twelve of these patients had received prior IL-2 therapy and had low frequencies of resting, latently infected CD4 cells. Viral load relapse to >50 copies/ml occurred in all 18 patients independent of prior IL-2 treatment, beginning most commonly during weeks 2-3 after cessation of HAART. The mean relapse rate constant was 0.45 (0.20 log(10) copies) day(-1), which was very similar to the mean viral clearance rate constant after drug resumption of 0.35 (0.15 log(10) copies) day(-1) (P = 0.28). One patient experienced a relapse delay to week 7. All patients except one experienced a relapse burden to >5,000 RNA copies/ml. Ex vivo labeling with BrdUrd showed that CD4 and CD8 cell turnover increased after withdrawal of HAART and correlated with viral load whereas lymphocyte turnover decreased after reinitiation of drug treatment. Virologic relapse occurs rapidly in patients who discontinue suppressive drug therapy, even in patients with a markedly diminished pool of resting, latently infected CD4(+) T cells.
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Affiliation(s)
- R T Davey
- National Institute of Allergy and Infectious Diseases, (NIAID), National Institutes of Health, Bethesda, MD 20892, USA.
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Davey RT, Chaitt DG, Albert JM, Piscitelli SC, Kovacs JA, Walker RE, Falloon J, Polis MA, Metcalf JA, Masur H, Dewar R, Baseler M, Fyfe G, Giedlin MA, Lane HC. A randomized trial of high- versus low-dose subcutaneous interleukin-2 outpatient therapy for early human immunodeficiency virus type 1 infection. J Infect Dis 1999; 179:849-58. [PMID: 10068580 DOI: 10.1086/314678] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [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: 11/03/2022] Open
Abstract
Forty-nine outpatients infected with human immunodeficiency virus with baseline CD4 cell counts >/=500/mm3, who were on stable antiretroviral therapy, were randomized to receive 5-day cycles of either low-dose (1.5 million IU [MIU] twice a day) or high-dose (7.5 MIU twice a day) subcutaneous (sc) interleukin (IL)-2 every 4 or every 8 weeks. High-dose recipients experienced mean slopes of +116.1 cells/month and +2.7 %/month in CD4 cells and percents, respectively, whereas low-dose recipients displayed mean slopes of +26.7 and +1.3% in the same parameters. At month 6, high-dose recipients achieved a 94.8% increase in mean CD4 cells over baseline compared with a 19.0% increase in low-dose recipients. While high-dose recipients encountered more constitutional side effects, these were generally not dose-limiting. High-dose scIL-2 therapy in outpatients with early HIV-1 infection was well tolerated and induced dramatic, sustained rises in CD4 cells.
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Affiliation(s)
- R T Davey
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1880, USA. rdavey@atlas. niaid.nih.gov
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Wilke D, Colwell B, Dewar R. Inflammatory breast carcinoma: comparison of survival of those diagnosed clinically, pathologically, or with both features. Am Surg 1998; 64:428-31. [PMID: 9585777] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There still remains some controversy as to whether or not there is a survival difference in patients with inflammatory breast carcinoma (IBC) with regard to whether they were diagnosed clinically, pathologically, or with both features. We conducted a retrospective chart review of all the patients diagnosed with IBC who were treated at the Nova Scotia Cancer Treatment and Research foundation between the years of 1990 and 1994, inclusive. Fifty-seven patients' charts were reviewed for recurrence or death up until Feb. 16, 1996. The overall survival of the 57 patients was 32 per cent (confidence interval, 16-48%) and 12 per cent (confidence interval, 0-26%) at 3 and 5 years, respectively. The survival times according to presentation (clinical, pathological, or both) at 3 and 5 years were 31 and 10 per cent for the clinically diagnosed group, 56 per cent at 3 years for the pathologically diagnosed group (5-year survival times could not be calculated), and 34 and 20 per cent for the group diagnosed both clinically and pathologically, respectively. Analysis by the log-rank test revealed that there was no significant difference in survival between these three groups. We conclude that there was no statistically significant difference in survival between those patients who presented clinically, pathologically, or with both features.
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Affiliation(s)
- D Wilke
- Department of Radiation Oncology, Queen Elizabeth II Health Sciences Center, Victoria General Hospital, Halifax, Nova Scotia, Canada
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38
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Simmons JEL, Dewar R, Ritchie JM, Ng FM. The application of virtual reality to tasks in manufacturing and assembly engineering. ACTA ACUST UNITED AC 1998. [DOI: 10.1007/bf02946528] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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39
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Kovacs JA, Bechtel C, Davey RT, Falloon J, Polis MA, Walker RE, Metcalf JA, Davey V, Piscitelli SC, Baseler M, Dewar R, Salzman NP, Masur H, Lane HC. Combination therapy with didanosine and interferon-alpha in human immunodeficiency virus-infected patients: results of a phase I/II trial. J Infect Dis 1996; 173:840-8. [PMID: 8603961 DOI: 10.1093/infdis/173.4.840] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A nonrandomized trial was undertaken to evaluate the combination of didanosine and interferon-alpha (INF-alpha) in human immunodeficiency virus (HIV)-infected patients. Thirty-six volunteers with >200 x 10(6) CD4 cells/L received didanosine (one 100-, 250-, or 375-mg sachet twice daily) for at least 6 weeks, following which IFN-alpha (1, 5, 10, or 15 MU/day) was begun. Didanosine (one 375-mg sachet twice daily) was substituted for zidovudine in 14 additional patients who had received IFN-alpha and zidovudine for 7-45 months. Thirty-five patients completed the 34-week study. Clinical or chemical pancreatitis was the most common (6 patients) dose-limiting toxicity. CD4 cell counts increased with didanosine but declined following the addition of IFN-alpha; CD4 cell percents tended to increase and remain elevated. Thus, combination therapy with didanosine and IFN-alpha can be safely administered to patients with HIV infection. The clinical benefit of this combination therapy will require further evaluation.
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Affiliation(s)
- J A Kovacs
- National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, USA
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40
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Aronson KJ, Siemiatycki J, Dewar R, Gérin M. Occupational risk factors for prostate cancer: results from a case-control study in Montréal, Québec, Canada. Am J Epidemiol 1996; 143:363-73. [PMID: 8633620 DOI: 10.1093/oxfordjournals.aje.a008750] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [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: 02/01/2023] Open
Abstract
A population-based case-control study of cancer and occupation was carried out in Montréal, Canada. Between 1979 and 1986, 449 pathologically confirmed cases of prostate cancer were interviewed, as well as 1,550 cancer controls and 533 population controls. Job histories were evaluated by a team of chemist/hygienists using a checklist of 294 workplace chemicals. After preliminary evaluation, 17 occupations, 11 industries, and 27 substances were selected for multivariate logistic regression analyses to estimate the odds ratio between each occupational circumstance and prostate cancer with control for potential confounders. There was moderate support for risk due to the following occupations: electrical power workers, water transport workers, aircraft fabricators, metal product fabricators, structural metal erectors, and railway transport workers. The following substances exhibited moderately strong associations: metallic dust, liquid fuel combustion products, lubricating oils and greases, and polyaromatic hydrocarbons from coal. While the population attributable risk, estimated at between 12% and 21% for these occupational exposures, may be an overestimate due to our method of analysis, even if the true attributable fraction were in the range of 5-10%, this represents an important public health issue.
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Affiliation(s)
- K J Aronson
- University of Toronto, Toronto, Ontario, Canada
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41
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Abstract
Polycyclic aromatic hydrocarbons (PAHs) demonstrate carcinogenic activity in animal models. Although some epidemiologic studies have implicated PAHs as risk factors for human cancer, the evidence reported to date has not been consistent. The purpose of this report is to describe the associations between occupational exposure to PAHs in the workplace and each of 14 types of cancer. A population-based, case-control study was carried out in Montreal to investigate associations between a large variety of environmental and occupational exposures on the one hand, and several types of cancer on the other. A detailed job history was obtained from each subject along with information on a number of potential confounders. Each job history was reviewed by a team of experts, who used this information to construct a corresponding history of occupational exposures. Among the PAH exposures considered were benzo(a)pyrene (B(a)P) and five categories of PAHs defined on the basis of the source material, namely, wood, petroleum, coal, other sources, and any source. Altogether, 3,730 cancer patients and 533 population controls were interviewed and their job exposure histories coded. For each of 14 types of cancer analyzed, three control groups were available: other cancer patients, population controls, and the pooled set of cancer and population controls. The associations between 14 cancer types and 6 PAH exposures were analyzed using logistic regression methods. For most types of cancer evaluated, there was no evidence of excess risk due to PAHs at the levels encountered in the occupations in which PAH exposure has been prevalent in the Montreal area. For a few cancer sites--the esophagus, the pancreas, and the prostate gland--there were suggestions of excess risk; these observations are noteworthy hypotheses for further investigation. For lung cancer, there appeared to be an increased risk due to PAHs among nonsmokers and light smokers, but not among heavy smokers.
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Affiliation(s)
- L Nadon
- Epidemiology and Biostatistics Unit, Institut Armand-Frappier, Université du Québec, Laval, Canada
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42
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Siemiatycki J, Dewar R, Nadon L, Gérin M. Occupational risk factors for bladder cancer: results from a case-control study in Montreal, Quebec, Canada. Am J Epidemiol 1994; 140:1061-80. [PMID: 7998589 DOI: 10.1093/oxfordjournals.aje.a117207] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A population-based case-control study of the associations between various cancers and occupational exposures was carried out in Montreal, Quebec, Canada. Between 1979 and 1986, 484 persons with pathologically confirmed cases of bladder cancer and 1,879 controls with cancers at other sites were interviewed, as was a series of 533 population controls. The job histories of these subjects were evaluated by a team of chemist/hygienists for evidence of exposure to a list of 294 workplace chemicals, and information on relevant non-occupational confounders was obtained. On the basis of results of preliminary analyses and literature review, 19 occupations, 11 industries, and 23 substances were selected for in-depth multivariate analysis. Logistic regression analyses were carried out to estimate the odds ratio between each of these occupational circumstances and bladder cancer. There was weak evidence that the following substances may be risk factors for bladder cancer: natural gas combustion products, aromatic amines, cadmium compounds, photographic products, acrylic fibers, polyethylene, titanium dioxide, and chlorine. Among the substances evaluated which showed no evidence of an association were benzo(a)pyrene, leather dust, and formaldehyde. Several occupations and industries were associated with bladder cancer, including motor vehicle drivers and textile dyers.
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Affiliation(s)
- J Siemiatycki
- Epidemiology and Biostatistics Unit, Institut Armand-Frappier, Laval, Québec, Canada
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43
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Pintos J, Franco EL, Oliveira BV, Kowalski LP, Curado MP, Dewar R. Maté, coffee, and tea consumption and risk of cancers of the upper aerodigestive tract in southern Brazil. Epidemiology 1994; 5:583-90. [PMID: 7841239 DOI: 10.1097/00001648-199411000-00005] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Consumption of maté, a tea-like infusion of the herb Ilex paraguariensis, is common in South America. Drinkers have high risks of upper aerodigestive tract cancers, but it is conceivable that this high risk may be attributable to confounding by smoking alcohol, and other exposures. To test this hypothesis, we analyzed the data from a case-control study of upper aerodigestive tract cancers conducted in Southern Brazil. We matched noncancer controls (N = 756) to cases (N = 378) on the basis of age, sex, and period of admission. We estimated the effect of mateé consumption by conditional logistic regression with adjustment for smoking, alcohol, sociodemographics, and several dietary items, considered as confounders. The unadjusted relative risk (RR) for all upper aerodigestive tract cancers was 2.1 [95% confidence interval (CI) = 1.6-2.7]. Some excess risk persisted after adjustment for potential confounders (RR = 1.6; 95% CI = 1.2-2.2). Most of the excess risk for maté drinkers was for oral (RR = 1.9; 95% CI = 1.1-3.3) and laryngeal (RR = 2.2; 95% CI = 2.2; 95% CI = 1.1-4.5) cancers. There was no evidence of associations with coffee and tea drinking. We conclude that the association of maté consumption with upper aerodigestive tract cancer risk is unlikely to result from insufficient control of confounding by critical exposures. Owing to its high prevalence in Southern South America, maté drinking may be linked to as many as 20% of all cases occurring in this region.
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Affiliation(s)
- J Pintos
- Department of Epidemiology, Armand-Frappier Institute, Goiania, Brazil
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Siemiatycki J, Dewar R, Krewski D, Désy M, Richardson L, Franco E. Are the apparent effects of cigarette smoking on lung and bladder cancers due to uncontrolled confounding by occupational exposures? Epidemiology 1994; 5:57-65. [PMID: 8117783 DOI: 10.1097/00001648-199401000-00010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
It has been suggested that the well known associations between smoking and cancer may in part reflect inadequately controlled confounding due to occupational exposures. The purpose of the present analysis is to describe the association between cigarette smoking and both lung and bladder cancers, taking into account the potential confounding effects of over 300 covariates, most of which represent occupational exposures. A population-based case-control study was undertaken in Montreal to investigate the associations between a large variety of environmental and occupational exposures, on the one hand, and several types of cancer, on the other. Interviews were carried out with male incident cases of several sites of cancer, including 857 lung cancers and 484 bladder cancers. A group of non-smoking-related cancers, comprising 1,707 interviewed subjects, was used as one control group. Additionally, 533 population controls were interviewed and constituted a second control group. Interview information included detailed lifetime smoking histories, job histories, and other potential confounders. Each job history was reviewed by a team of experts who translated it into a history of occupational exposures. These occupational exposures, as well as nonoccupational covariates, were treated as potential confounders in the analysis of cigarette smoking effects. Regardless of whether population controls or cancer controls were used, the odds ratio (OR) between smoking and lung cancer (ranging from 12 to 16 for ever vs never smokers) was not materially affected by adjustment for occupational exposures. The odds ratios for bladder cancer (ranging from 2 to 3) were also unaffected by confounding due to occupational exposures.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Siemiatycki
- Epidemiology and Biostatistics Unit, Institut Armand-Frappier, Université du Québec, Laval-des-Rapides, Canada
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Finucane P, Nicklason F, Dewar R, Woodhead JS, MacMahon M, Kelleher BP, Dockrell D, O’Broin SD, Ryder RJW, Walsh JB, Coakley D, Hegarty V, Hassan J, Yanni G, Whelan A, Feighery C, Bresnihan B, Keane J, Chan F, Over J, Finnucane P, Liston R, Clinch D, Scott T, Moloney B, Tiernan E, White S, Murphy K, Henry C, Twomey C, Hyland CM, Gregg ME, Beringer TRO, Henderson SA, Finlay OE, Murphy NM, Boreham CAG, Mollan RAB, Gilmore DH, Browne JP, O’Boyle CA, McGee HM, O’Malley KM, Joyce CRB, Mulkerrin E, Hampton D, Donovan K, Penney M, Sykes D, O’Neill D, Surmon D, Wilcock GK, O’Mahony D, Rowan M, Feely J, Lyons RA, McCarthy R, Murphy S, Rajan L, Fielding JF, Clements L, Cherot E, Greenough WB, West KP. Irish gerontological society. Ir J Med Sci 1992. [DOI: 10.1007/bf02942385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The blood pressure in both arms of 103 unselected hemiplegic patients was measured using a random-zero sphygmomanometer. Although for the whole sample the mean blood pressure in the paretic and unaffected arm was similar, a significant difference was found when the patients were subdivided according to the tone of the arm. The blood pressure was higher in paretic arms of patients with a spastic stroke and lower in the affected arm if the tone was flaccid. No other characteristics were associated with significant blood pressure differences, so that the findings appear to be directly related to changes in muscle tone. After a stroke the blood pressure should always be measured in the unaffected arm because changes in tone make measurements unreliable.
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Affiliation(s)
- R Dewar
- University Department of Geriatrics, Cardiff Royal Infirmary, UK
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47
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Soskolne CL, Jhangri GS, Siemiatycki J, Lakhani R, Dewar R, Burch JD, Howe GR, Miller AB. Occupational exposure to sulfuric acid in southern Ontario, Canada, in association with laryngeal cancer. Scand J Work Environ Health 1992; 18:225-32. [PMID: 1411364 DOI: 10.5271/sjweh.1585] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [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: 12/26/2022] Open
Abstract
A case-referent study, designed to test associations between asbestos, nickel, and the development of laryngeal cancer, was conducted in southern Ontario in 1977-1979. The cases were individually matched to neighborhood referents for gender and age. This constituted the primary study. Personal interviews had secured tobacco, alcohol, and detailed work histories. To 183 of the male pairs was added retrospective assessments of sulfuric acid exposure for each job, blind of disease status; this constituted the data base for an augmented secondary analysis. Logistic regression revealed statistically significant odds ratios when tobacco and alcohol were controlled. Exposure-response gradients were strongly positive with odds ratios in the range of 1.97 [95% confidence interval (95% CI) 0.63-6.13] for short duration-low level exposure through 6.91 [95% CI 2.20-21.74] for long duration-higher level exposure employing progressively more specific definitions of exposure. Asbestos as a confounder and the interaction terms examined were nonsignificant. These findings are corroborative of those of other studies.
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Affiliation(s)
- C L Soskolne
- Department of Health Services Administration and Community Medicine, Faculty of Medicine, University of Alberta, Edmonton, Canada
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48
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Abstract
An oral glucose tolerance test (OGTT, 75 g WHO criteria) was applied to healthy elderly subjects (mean age 76 years) within a week of measurement of random blood glucose and glycosylated haemoglobin (HbA1). The 'Corning' method was used to assay HbA1 (established normal range for our laboratory 5-8%). Sixty-five subjects (38 women) of whom 54 were not diabetic on WHO criteria for OGTT participated in the study. Five of the 54 patients with non-diabetic OGTT results had abnormal HbA1 (greater than 8%). These five subjects had no evidence of impaired glucose tolerance. Eleven subjects had diabetic OGTT results of whom only four had raised HbA1 assay results. Seven subjects had normal HbA1 in spite of diabetic OGTT. The mean HbA1 in the group of subjects with normal OGTT (n = 52) was 6.7% (SD 1.05, range 4.6-8.7%). It appears from our study that the normal range of HbA1 in elderly subjects is not markedly different from established normal values. The poor sensitivity (36%) and predictive value (44%) of abnormal HbA1 in detecting diabetes, as shown in our study, would not permit its use for screening purposes nor as a confirmatory test for diabetes in elderly subjects.
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Affiliation(s)
- E C Mulkerrin
- Department of Geriatric Medicine, University Hospital of Wales, Heath Park, Cardiff
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49
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Mulkerrin E, Nicklason F, Sykes D, Dewar R, Bayer A, Finucane P. Assessment of Cognitive Impairment in Patients Being Discharged from Geriatric Wards. Age Ageing 1992. [DOI: 10.1093/ageing/21.suppl_1.p15-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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50
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Dewar R, Mulkerin E. Heart Failure with Normal Systolic Function is Common in the Elderly. Age Ageing 1992. [DOI: 10.1093/ageing/21.suppl_2.p19-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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