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32 Elevated Plasma pTau-181 is Associated with Lower Global Cognition and Executive Function in Older Adults
- Arunima Kapoor, Jean K Ho, Shubir Dutt, Yanrong Li, John P Alitin, Jung Yun Jang, Aimee Gaubert, Amy Nguyen, Belinda Yew, Anna E Blanken, Isabel J Sible, Anisa Marshall, Fatemah Shenasa, Alessandra Martini, Kathleen E Rodgers, Elizabeth Head, Daniel A Nation
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 907-908
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Objective:
Aggregation of phosphorylated tau (pTau) is a hallmark feature of Alzheimer’s disease (AD). Novel assays now allow pTau to be measured in plasma. Elevated plasma pTau predicts subsequent development of AD, cortical atrophy and AD-related pathologies in the brain. We aimed to determine whether elevated pTau is associated with cognitive functioning in older adults prior to the development of dementia.
Participants and Methods:Independently living older adults (N = 48, mean age = 70.0 years; SD = 7.7; age range 55-88 years; 35.4% male) free of dementia or clinical stroke were recruited from the community and underwent blood draw and neuropsychological assessment. Plasma was assayed using the Quanterix Simoa® pTau-181 V2 Advantage Kit to quantify pTau-181 levels and APOE genotyping was conducted on the blood cell pellet fraction obtained from plasma separation. Global cognition was assessed using the Dementia Rating Scale-2 (DRS-2) and executive function was assessed using the Stroop, D-KEFS-2 Fluency, and Trails Making Test. Diagnosis of mild cognitive impairment (MCI) was determined based on overall neuropsychological performance. Participants were diagnosed as MCI if they scored >1 SD below norm-referenced values on 2 or more tests within a domain (language, executive, memory) or on 3 tests across domains.
Results:Multiple linear regression analysis revealed a significant negative association between plasma pTau-181 levels and DRS-2 (B = -2.57, 95% CI (-3.68, -1.47), p <.001), Stroop Color-Word score (B = -2.64, 95% CI (-4.56, - 0.71), p = .009) and Fruits and Vegetables Fluency (B = -1.67, 95% CI (-2.84, -0.49), p = .007), adjusting for age, sex, education and APOE4 status. MCI diagnosis was determined for 43 participants, of which 8 (18.6%) met criteria. Logistic regression analysis revealed that pTau-181 levels are associated with increased odds of MCI diagnosis (OR = 2.18, 95% CI (1.01, 4.68), p = .046), after accounting for age, sex, education and APOE4 status.
Conclusions:Elevated plasma pTau-181 is associated with worse cognition, particularly executive function, and predicts MCI diagnosis in older adults. Higher plasma pTau-181 was associated with increased odds of MCI diagnosis. Detection of pTau-181 in plasma allows a novel, non-invasive method to detect burden of one form of AD pathology. These findings lend support to the use of plasma pTau-181 as a valuable marker in detecting even early cognitive changes prior to the development of AD. Additional longitudinal studies are warranted to explore the prognostic value of plasma pTau-181 over time.
5 Associations Between Regional Perfusion and Locus Coeruleus MRI Contrast are Moderated by Plasma Alzheimer’s Disease Biomarkers in Older Adults
- Shubir Dutt, Shelby L Bachman, Yanrong Li, Belinda Yew, Jung Y Jang, Jean K Ho, Kaoru Nashiro, Jungwon Min, Hyun Joo Yoo, Aimee Gaubert, Amy Nguyen, Isabel J Sible, Anna E Blanken, Anisa J Marshall, Arunima Kapoor, John P Alitin, Kim Hoang, Alessandra C Martini, Elizabeth Head, Xingfeng Shao, Danny J J Wang, Mara Mather, Daniel A Nation
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 610-611
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Objective:
The locus coeruleus (LC) innervates the cerebrovasculature and plays a crucial role in optimal regulation of cerebral blood flow. However, no human studies to date have examined links between these systems with widely available neuroimaging methods. We quantified associations between LC structural integrity and regional cortical perfusion and probed whether varying levels of plasma Alzheimer’s disease (AD) biomarkers (Aß42/40 ratio and ptau181) moderated these relationships.
Participants and Methods:64 dementia-free community-dwelling older adults (ages 55-87) recruited across two studies underwent structural and functional neuroimaging on the same MRI scanner. 3D-pCASL MRI measured regional cerebral blood flow in limbic and frontal cortical regions, while T1-FSE MRI quantified rostral LC-MRI contrast, a well-established proxy measure of LC structural integrity. A subset of participants underwent fasting blood draw to measure plasma AD biomarker concentrations (Aß42/40 ratio and ptau181). Multiple linear regression models examined associations between perfusion and LC integrity, with rostral LC-MRI contrast as predictor, regional CBF as outcome, and age and study as covariates. Moderation analyses included additional terms for plasma AD biomarker concentration and plasma x LC interaction.
Results:Greater rostral LC-MRI contrast was linked to lower regional perfusion in limbic regions, such as the amygdala (ß = -0.25, p = 0.049) and entorhinal cortex (ß = -0.20, p = 0.042), but was linked to higher regional perfusion in frontal cortical regions, such as the lateral (ß = 0.28, p = 0.003) and medial (ß = 0.24, p = 0.05) orbitofrontal (OFC) cortices. Plasma amyloid levels moderated the relationship between rostral LC and amygdala CBF (Aß42/40 ratio x rostral LC interaction term ß = -0.31, p = 0.021), such that as plasma Aß42/40 ratio decreased (i.e., greater pathology), the strength of the negative relationship between rostral LC integrity and amygdala perfusion decreased. Plasma ptau181levels moderated the relationship between rostral LC and entorhinal CBF (ptau181 x rostral LC interaction term ß = 0.64, p = 0.001), such that as ptau181 increased (i.e., greater pathology), the strength of the negative relationship between rostral LC integrity and entorhinal perfusion decreased. For frontal cortical regions, ptau181 levels moderated the relationship between rostral LC and lateral OFC perfusion (ptau181 x rostral LC interaction term ß = -0.54, p = .004), as well as between rostral LC and medial OFC perfusion (ptau181 x rostral LC interaction term ß = -0.53, p = .005), such that as ptau181 increased (i.e., greater pathology), the strength of the positive relationship between rostral LC integrity and frontal perfusion decreased.
Conclusions:LC integrity is linked to regional cortical perfusion in non-demented older adults, and these relationships are moderated by plasma AD biomarker concentrations. Variable directionality of the associations between the LC and frontal versus limbic perfusion, as well as the differential moderating effects of plasma AD biomarkers, may signify a compensatory mechanism and a shifting pattern of hyperemia in the presence of aggregating AD pathology. Linking LC integrity and cerebrovascular regulation may represent an important understudied pathway of dementia risk and may help to bridge competing theories of dementia progression in preclinical AD studies.
41538 Characterizing Opioid Overdose Hotspots for Targeted Overdose Prevention and Treatment
- Elizabeth A. Samuels, William Goedel, Lauren Conkey, Jennifer Koziol, Sarah Karim, Rachel P. Scagos, Lee Ann Jordison Keeler, Rachel Yorlets, Neha Reddy, Sara Becker, Roland Merchant, Brandon D. L. Marshall
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- Journal:
- Journal of Clinical and Translational Science / Volume 5 / Issue s1 / March 2021
- Published online by Cambridge University Press:
- 31 March 2021, pp. 84-85
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ABSTRACT IMPACT: Identifying factors associated with opioid overdoses will enable better resource allocation in communities most impacted by the overdose epidemic. OBJECTIVES/GOALS: Opioid overdoses often occur in hotspots identified by geographic and temporal trends. This study uses principles of community engaged research to identify neighborhood and community-level factors associated with opioid overdose within overdose hotspots which can be targets for novel intervention design. METHODS/STUDY POPULATION: We conducted an environmental scan in three overdose hotspots’‘ two in an urban center and one in a small city’‘ identified by the Rhode Island Department of Health as having the highest opioid overdose burden in Rhode Island. We engaged hotspot community stakeholders to identify neighborhood factors to map within each hotspot. Locations of addiction treatment, public transportation, harm reduction programs, public facilities (i.e., libraries, parks), first responders, and social services agencies were converted to latitude and longitude and mapped in ArcGIS. Using Esri Service Areas, we will evaluate the service areas of stationary services. We will overlay overdose events and use logistic regression identify neighborhood factors associated with overdose by comparing hotspot and non-hotspot neighborhoods. RESULTS/ANTICIPATED RESULTS: We anticipate that there will be differing neighborhood characteristics associated with overdose events in the densely populated urban area and those in the smaller city. The urban area hotspots will have overlapping social services, addiction treatment, and transportation service areas, while the small city will have fewer community resources without overlapping service areas and reduced public transportation access. We anticipate that overdoses will occur during times of the day when services are not available. Overall, overdose hotspots will be associated with increased census block level unemployment, homelessness, vacant housing, and low food security. DISCUSSION/SIGNIFICANCE OF FINDINGS: Identifying factors associated with opioid overdoses will enable better resource allocation in communities most impacted by the overdose epidemic. Study results will be used for novel intervention design to prevent opioid overdose deaths in communities with high burden of opioid overdose.
Lessons learned in the use of clinical registry data in a multi-centre prospective study: the Pediatric Heart Network Residual Lesion Score Study
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- Carol J. Prospero, Felicia L. Trachtenberg, Victoria L. Pemberton, Sara K. Pasquali, Brett R. Anderson, Kathleen E. Ash, Jessica Bainton, Carolyn Dunbar-Masterson, Eric M. Graham, Michelle S. Hamstra, Danielle Hollenbeck-Pringle, Jeffrey P. Jacobs, Marshall L. Jacobs, Rija John, Linda M. Lambert, Matthew E. Oster, Elizabeth Swan, Abigail Waldron, Meena Nathan, for the Pediatric Heart Network Investigators
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- Journal:
- Cardiology in the Young / Volume 29 / Issue 7 / July 2019
- Published online by Cambridge University Press:
- 17 June 2019, pp. 930-938
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Background:
Using existing data from clinical registries to support clinical trials and other prospective studies has the potential to improve research efficiency. However, little has been reported about staff experiences and lessons learned from implementation of this method in pediatric cardiology.
Objectives:We describe the process of using existing registry data in the Pediatric Heart Network Residual Lesion Score Study, report stakeholders’ perspectives, and provide recommendations to guide future studies using this methodology.
Methods:The Residual Lesion Score Study, a 17-site prospective, observational study, piloted the use of existing local surgical registry data (collected for submission to the Society of Thoracic Surgeons-Congenital Heart Surgery Database) to supplement manual data collection. A survey regarding processes and perceptions was administered to study site and data coordinating center staff.
Results:Survey response rate was 98% (54/55). Overall, 57% perceived that using registry data saved research staff time in the current study, and 74% perceived that it would save time in future studies; 55% noted significant upfront time in developing a methodology for extracting registry data. Survey recommendations included simplifying data extraction processes and tailoring to the needs of the study, understanding registry characteristics to maximise data quality and security, and involving all stakeholders in design and implementation processes.
Conclusions:Use of existing registry data was perceived to save time and promote efficiency. Consideration must be given to the upfront investment of time and resources needed. Ongoing efforts focussed on automating and centralising data management may aid in further optimising this methodology for future studies.
Modeling Recreational Amenities in an Urban Setting: Location, Congestion, and Substitution Effects
- Frances R. Homans, Elizabeth P. Marshall
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- Agricultural and Resource Economics Review / Volume 37 / Issue 2 / October 2008
- Published online by Cambridge University Press:
- 15 September 2016, pp. 257-272
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In this article, we introduce a recreational amenity—a greenbelt park—into a simple urban economic model. For multiple possible park placements, we solve for the associated equilibrium urban structure, including the equilibrium rent gradient, city boundary, total number of park visits, the overall utility level, and total vehicle miles traveled. We examine how these change with alternative park placement sites. We then show how two modifications of the basic model—allowing congestion at the site to affect site quality, and introducing the possibility of a substitute site at the city's periphery—affect our conclusions about how greenbelt location influences urban structure.
NICE v. SIGN on psychosis and schizophrenia: Same roots, similar guidelines, different interpretations
- Tim Kendall, Craig J. Whittington, Elizabeth Kuipers, Sonia Johnson, Max J. Birchwood, Max Marshall, Anthony P. Morrison,
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- Journal:
- The British Journal of Psychiatry / Volume 208 / Issue 4 / April 2016
- Published online by Cambridge University Press:
- 02 January 2018, pp. 316-319
- Print publication:
- April 2016
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A recent editorial claimed that the 2014 National Institute for Health and Care Excellence (NICE) guideline on psychosis and schizophrenia, unlike its equivalent 2013 Scottish Intercollegiate Guidelines Network (SIGN) guideline, is biased towards psychosocial treatments and against drug treatments. In this paper we underline that the NICE and SIGN guidelines recommend similar interventions, but that the NICE guideline has more rigorous methodology. Our analysis suggests that the authors of the editorial appear to have succumbed to bias themselves.
Use of vitamin D supplements during infancy in an international feeding trial
- Eveliina Lehtonen, Anne Ormisson, Anita Nucci, David Cuthbertson, Susa Sorkio, Mila Hyytinen, Kirsi Alahuhta, Carol Berseth, Marja Salonen, Shayne Taback, Margaret Franciscus, Teba González-Frutos, Tuuli E Korhonen, Margaret L Lawson, Dorothy J Becker, Jeffrey P Krischer, Mikael Knip, Suvi M Virtanen, , Thomas Mandrup-Poulsen, Elias Arjas, Åke Lernmark, Barbara Schmidt, Jeffrey P. Krischer, Hans K. Åkerblom, Mila Hyytinen, Mikael Knip, Katriina Koski, Matti Koski, Eeva Pajakkala, Marja Salonen, David Cuthbertson, Jeffrey P. Krischer, Linda Shanker, Brenda Bradley, Hans-Michael Dosch, John Dupré, William Fraser, Margaret Lawson, Jeffrey L. Mahon, Mathew Sermer, Shayne P. Taback, Dorothy Becker, Margaret Franciscus, Anita Nucci, Jerry Palmer, Minna Pekkala, Suvi M. Virtanen, Jacki Catteau, Neville Howard, Patricia Crock, Maria Craig, Cheril L. Clarson, Lynda Bere, David Thompson, Daniel Metzger, Colleen Marshall, Jennifer Kwan, David K. Stephure, Daniele Pacaud, Wendy Schwarz, Rose Girgis, Marilyn Thompson, Shayne P. Taback, Daniel Catte, Margaret L. Lawson, Brenda Bradley, Denis Daneman, Mathew Sermer, Mary-Jean Martin, Valérie Morin, Lyne Frenette, Suzanne Ferland, Susan Sanderson, Kathy Heath, Céline Huot, Monique Gonthier, Maryse Thibeault, Laurent Legault, Diane Laforte, Elizabeth A. Cummings, Karen Scott, Tracey Bridger, Cheryl Crummell, Robyn Houlden, Adriana Breen, George Carson, Sheila Kelly, Koravangattu Sankaran, Marie Penner, Richard A. White, Nancy King, James Popkin, Laurie Robson, Eva Al Taji, Irena Aldhoon, Pavla Mendlova, Jan Vavrinec, Jan Vosahlo, Ludmila Brazdova, Jitrenka Venhacova, Petra Venhacova, Adam Cipra, Zdenka Tomsikova, Petra Krckova, Pavla Gogelova, Ülle Einberg, Mall-Anne Riikjärv, Anne Ormisson, Vallo Tillmann, Päivi Kleemola, Anna Parkkola, Heli Suomalainen, Anna-Liisa Järvenpää, Anu-Maaria Hämälainen, Hannu Haavisto, Sirpa Tenhola, Pentti Lautala, Pia Salonen, Susanna Aspholm, Heli Siljander, Carita Holm, Samuli Ylitalo, Raisa Lounamaa, Anja Nuuja, Timo Talvitie, Kaija Lindström, Hanna Huopio, Jouni Pesola, Riitta Veijola, Päivi Tapanainen, Abram Alar, Paavo Korpela, Marja-Liisa Käär, Taina Mustila, Ritva Virransalo, Päivi Nykänen, Bärbel Aschemeier, Thomas Danne, Olga Kordonouri, Dóra Krikovszky, László Madácsy, Yeganeh Manon Khazrai, Ernesto Maddaloni, Paolo Pozzilli, Carla Mannu, Marco Songini, Carine de Beaufort, Ulrike Schierloh, Jan Bruining, Margriet Bisschoff, Aleksander Basiak, Renata Wasikowa, Marta Ciechanowska, Grazyna Deja, Przemyslawa Jarosz-Chobot, Agnieszka Szadkowska, Katarzyna Cypryk, Malgorzata Zawodniak-Szalapska, Luis Castano, Teba Gonzalez Frutos, Mirentxu Oyarzabal, Manuel Serrano-Ríos, María Teresa Martínez-Larrad, Federico Gustavo Hawkins, Dolores Rodriguez Arnau, Johnny Ludvigsson, Malgorzata Smolinska Konefal, Ragnar Hanas, Bengt Lindblad, Nils-Osten Nilsson, Hans Fors, Maria Nordwall, Agne Lindh, Hans Edenwall, Jan Aman, Calle Johansson, Margrit Gadient, Eugen Schoenle, Dorothy Becker, Ashi Daftary, Margaret Franciscus, Carol Gilmour, Jerry Palmer, Rachel Taculad, Marilyn Tanner-Blasiar, Neil White, Uday Devaskar, Heather Horowitz, Lisa Rogers, Roxana Colon, Teresa Frazer, Jose Torres, Robin Goland, Ellen Greenberg, Maudene Nelson, Holly Schachner, Barney Softness, Jorma Ilonen, Massimo Trucco, Lynn Nichol, Erkki Savilahti, Taina Härkönen, Mikael Knip, Outi Vaarala, Kristiina Luopajärvi, Hans-Michael Dosch
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- Journal:
- Public Health Nutrition / Volume 17 / Issue 4 / April 2014
- Published online by Cambridge University Press:
- 24 June 2013, pp. 810-822
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Objective
To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.
DesignLongitudinal study.
SettingInformation about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.
SubjectsInfants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.
ResultsDaily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80 % of the infants), with somewhat lower rates observed in Southern Europe (>60 %). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g. 71 % v. 44 % at 6 months of age). Less than 2 % of infants in the USA and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.
ConclusionsMost of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the USA and Australia very few were given supplementation.
Contributors
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- By Elizabeth Baker Brite, Gwen P. Bennett, Victor Buchli, Claudia Chang, Geoff Emberling, Alan F. Greene, Charles W. Hartley, MaryFran Heinsch, Fiona Kidd, Philip L. Kohl, Hu Lin, Katheryn M. Linduff, Maureen E. Marshall, Belinda H. Monahan, Eileen M. Murphy, Michelle Negus Cleary, David L. Peterson, Irina Lita Shingiray, Victor A. Shnirelman, Adam T. Smith, Joanna Sofaer, Wu Xin, Yang Jianhua, G. Bike Yazıcıoğlu
- Edited by Charles W. Hartley, University of Chicago, G. Bike Yazicioğlu, University of Chicago, Adam T. Smith, Cornell University, New York
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- Book:
- The Archaeology of Power and Politics in Eurasia
- Published online:
- 05 December 2012
- Print publication:
- 19 November 2012, pp xiii-xviii
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Contributors
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- By Joanne R. Adler, David A. Alexander, Laurence Alison, Catherine C. Ayoub, Peter Banister, Anthony R. Beech, Amanda Biggs, Julian Boon, Adrian Bowers, Neil Brewer, Eric Broekaert, Paula Brough, Jennifer M. Brown, Kevin Browne, Elizabeth A. Campbell, David Canter, Michael Carlin, Shihning Chou, Martin A. Conway, Claire Cooke, David Cooke, Ilse Derluyn, Robert J. Edelmann, Vincent Egan, Tom Ellis, Marie Eyre, David P. Farrington, Seena Fazel, Daniel B. Fishman, Victoria Follette, Katarina Fritzon, Elizabeth Gilchrist, Nathan D. Gillard, Renée Gobeil, Agnieszka Golec de Zavala, Jane Goodman-Delahunty, Lynsey Gozna, Don Grubin, Gisli H. Gudjonsson, Helinä Häkkänen-Nyholm, Guy Hall, Nathan Hall, Roisin Hall, Sean Hammond, Leigh Harkins, Grant T. Harris, Camilla Herbert, Robert D. Hoge, Todd E. Hogue, Clive R. Hollin, Lorraine Hope, Miranda A. H. Horvath, Kevin Howells, Carol A. Ireland, Jane L. Ireland, Mark Kebbell, Michael King, Bruce D. Kirkcaldy, Heidi La Bash, Cara Laney, William R. Lindsay, Elizabeth F. Loftus, L. E. Marshall, W. L. Marshall, James McGuire, Neil McKeganey, T. M. McMillan, Mary McMurran, Joav Merrick, Becky Milne, Joanne M. Nadkarni, Claire Nee, M. D. O’Brien, William O’Donohue, Darragh O’Neill, Jane Palmer, Adria Pearson, Derek Perkins, Devon L. L. Polaschek, Louise E. Porter, Charlotte C. Powell, Graham E. Powell, Martine Powell, Christine Puckering, Ethel Quayle, Vernon L. Quinsey, Marnie E. Rice, Randall Richardson-Vejlgaard, Richard Rogers, Louis B Schlesinger, Carolyn Semmler, G. A. Serran, Ralph C. Serin, John L. Taylor, Max Taylor, Brian Thomas-Peter, Paul A. Tiffin, Graham Towl, Rosie Travers, Arlene Vetere, Graham Wagstaff, Helen Wakeling, Fiona Warren, Brandon C. Welsh, David Wexler, Margaret Wilson, Dan Yarmey, Susan Young
- Edited by Jennifer M. Brown, London School of Economics and Political Science, Elizabeth A. Campbell, University of Glasgow
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- Book:
- The Cambridge Handbook of Forensic Psychology
- Published online:
- 06 July 2010
- Print publication:
- 29 April 2010, pp xix-xxiii
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Role of Environmental Surveillance in Determining the Risk of Hospital-Acquired Legionellosis: A National Surveillance Study With Clinical Correlations
- Janet E. Stout, Robert R. Muder, Sue Mietzner, Marilyn M. Wagener, Mary Beth Perri, Kathleen DeRoos, Dona Goodrich, William Arnold, Theresa Williamson, Ola Ruark, Christine Treadway, Elizabeth C. Eckstein, Debra Marshall, Mary Ellen Rafferty, Kathleen Sarro, Joann Page, Robert Jenkins, Gina Oda, Kathleen J. Shimoda, Marcus J. Zervos, Marvin Bittner, Sharon L. Camhi, Anand P. Panwalker, Curtis J. Donskey, Minh-Hong Nguyen, Mark Holodniy, Victor L. Yu, Legionella Study Group
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- Journal:
- Infection Control & Hospital Epidemiology / Volume 28 / Issue 7 / July 2007
- Published online by Cambridge University Press:
- 02 January 2015, pp. 818-824
- Print publication:
- July 2007
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Objective.
Hospital-acquired Legionella pneumonia has a fatality rate of 28%, and the source is the water distribution system. Two prevention strategies have been advocated. One approach to prevention is clinical surveillance for disease without routine environmental monitoring. Another approach recommends environmental monitoring even in the absence of known cases of Legionella pneumonia. We determined the Legionella colonization status of water systems in hospitals to establish whether the results of environmental surveillance correlated with discovery of disease. None of these hospitals had previously experienced endemic hospital-acquired Legionella pneumonia.
Design.Cohort study.
Setting.Twenty US hospitals in 13 states.
Interventions.Hospitals performed clinical and environmental surveillance for Legionella from 2000 through 2002. All specimens were shipped to the Special Pathogens Laboratory at the Veterans Affairs Pittsburgh Medical Center.
Results.Legionella pneumophila and Legionella anisa were isolated from 14 (70%) of 20 hospital water systems. Of 676 environmental samples, 198 (29%) were positive for Legionella species. High-level colonization of the water system (30% or more of the distal outlets were positive for L. pneumophila) was demonstrated for 6 (43%) of the 14 hospitals with positive findings. L. pneumophila serogroup 1 was detected in 5 of these 6 hospitals, whereas 1 hospital was colonized with L. pneumophila serogroup 5. A total of 633 patients were evaluated for Legionella pneumonia from 12 (60%) of the 20 hospitals: 377 by urinary antigen testing and 577 by sputum culture. Hospital-acquired Legionella pneumonia was identified in 4 hospitals, all of which were hospitals with L. pneumophila serogroup 1 found in 30% or more of the distal outlets. No cases of disease due to other serogroups or species (L. anisa) were identified.
Conclusion.Environmental monitoring followed by clinical surveillance was successful in uncovering previously unrecognized cases of hospital-acquired Legionella pneumonia.
Identification of Factors That Disrupt Negative Air Pressurization of Respiratory Isolation Rooms
- Nicholas Pavelchak, Ronald P. DePersis, Matthew London, Rachel Stricof, Margaret Oxtoby, George DiFerdinando, Jr, Elizabeth Marshall
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- Journal:
- Infection Control & Hospital Epidemiology / Volume 21 / Issue 3 / March 2000
- Published online by Cambridge University Press:
- 02 January 2015, pp. 191-195
- Print publication:
- March 2000
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Objectives:
To investigate the airflow characteristics of respiratory isolation rooms (IRs) and to evaluate the use of visible smoke as a monitoring tool.
Methods:Industrial hygienists from the New York State Department of Health evaluated 140 designated IRs in 38 facilities within New York State during 1992 to 1998. The rooms were located in the following settings: hospitals (59%), correctional facilities (40%), and nursing homes (1%). Each room was tested with visible smoke for directional airflow into the patient room (ie, negative air pressure relative to adjacent areas). Information was obtained on each facility's policies and procedures for maintaining and monitoring the operation of the IRs.
Results:Inappropriate outward airflow was observed in 38% of the IRs tested. Multiple factors were associated with outward airflow direction, including ventilation systems not balanced (54% of failed rooms), shared anterooms (14%), turbulent airflow patterns (11%), and automated control system inaccuracies (10%). Of the 140 tested rooms, 38 (27%) had either electrical or mechanical devices to monitor air pressurization continuously. The direction of airflow at the door to 50% (19/38) of these rooms was the opposite of that indicated by the continuous monitors at the time of our evaluations. The inability of continuous monitors to indicate the direction of airflow was associated with instrument limitations (74%) and malfunction of the devices (26%). In one facility, daily smoke testing by infection control staff was responsible for identifying the malfunction of a state-of-the-art computerized ventilation monitoring and control system in a room housing a patient infectious with drug-resistant tuberculosis.
Conclusion:A substantial percentage of IRs did not meet the negative air pressure criterion. These failures were associated with a variety of characteristics in the design and operation of the IRs. Our findings indicate that a balanced ventilation system does not guarantee inward airflow direction. Devices that continuously monitor and, in some cases, control the pressurization of IRs had poor reliability. This study demonstrates the utility of using visible smoke for testing directional airflow of IRs, whether or not continuous monitors are used. Institutional tuberculosis control programs should include provisions for appropriate monitoring and maintenance of IR systems on a frequent basis, including the use of visible smoke.
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