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Wu S, Powell V, Chintoh A, Alarabi M, Agarwal SM, Remington G. Safety of BEN guidelines in clozapine treatment: A Canadian perspective. Schizophr Res 2024; 264:451-456. [PMID: 38262312 DOI: 10.1016/j.schres.2024.01.021] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 11/29/2023] [Accepted: 01/08/2024] [Indexed: 01/25/2024]
Abstract
OBJECTIVE Unidentified benign ethnic neutropenia (BEN) has been recognized as a factor contributing to clozapine underutilization and discontinuation. Guidelines were implemented to accommodate BEN in Canada, and our main objective was to evaluate clozapine's safety in a sample of Canadian psychiatric patients with BEN. METHOD A retrospective chart review was conducted at the Centre for Addiction and Mental Health, Toronto, Canada. Through the clozapine clinic registry, participants were identified who (i) received clozapine using the approved BEN guidelines for hematological monitoring, and (ii) had at least one complete blood count pre- and post-clozapine initiation. RESULTS Our sample population was comprised of 41 BEN patients who were African-Caribbean (49 %), African (34 %), African-North American (12 %), Middle Eastern (2 %), and Indian-Caribbean (2 %). There was a significant reduction in hematological alerts for these patients while monitored under BEN guidelines (p < 0.001). The mean within-patient ANC value was not significantly different one year after clozapine initiation compared to the pre-clozapine baseline (p = 0.069). None of the patients discontinued clozapine for hematological reasons. CONCLUSIONS Findings demonstrated that patients monitored under the modified hematological guidelines for BEN can be safely treated with clozapine. These findings have important clinical ramifications as increased implementation of BEN guidelines may allow for broader use of clozapine.
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Affiliation(s)
- Sally Wu
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada; Temerty Faculty of Medicine, Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Valerie Powell
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Araba Chintoh
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Mohammed Alarabi
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada; Department of Psychiatry, King Saud University, Riyadh, Saudi Arabia
| | - Sri Mahavir Agarwal
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada; Temerty Faculty of Medicine, Institute of Medical Sciences, University of Toronto, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Gary Remington
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada; Temerty Faculty of Medicine, Institute of Medical Sciences, University of Toronto, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada; Department of Psychological Clinical Science, University of Toronto Scarborough, Toronto, ON, Canada.
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Stogios N, Maksyutynska K, Navagnanavel J, Sanches M, Powell V, Gerretsen P, Graff-Guerrero A, Chintoh AF, Foussias G, Remington G, Hahn MK, Agarwal SM. Metformin for the prevention of clozapine-induced weight gain: A retrospective naturalistic cohort study. Acta Psychiatr Scand 2022; 146:190-200. [PMID: 35726126 DOI: 10.1111/acps.13462] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 06/10/2022] [Accepted: 06/11/2022] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Clozapine is presently the sole antipsychotic with an indication for treatment-resistant Schizophrenia, but is associated with significant weight gain and other metabolic aberrations. This retrospective chart review aimed to evaluate the effectiveness of adjunctive metformin in preventing clozapine-induced weight gain. METHODS We conducted a retrospective chart review of patients newly initiated on clozapine at the Centre for Addiction and Mental Health in Canada, from November 2014 to April 2021. Our primary outcome was body weight at 6 and 12 months after clozapine initiation. Other metabolic parameters served as secondary outcomes. RESULTS Among 396 patients (males: 71.5%, mean age: 42.8 years) initiated on clozapine, 69 were on metformin or prescribed it ≤3 months after clozapine initiation. The clozapine+metformin group demonstrated less weight gain compared with the clozapine-only group at 6 months (clozapine+metformin: -0.15 kg [SE = 1.08] vs. clozapine-only: 2.99 kg, SE = 0.54) and 12 months after clozapine initiation (clozapine+metformin: -0.67 kg, SE = 1.22 vs. clozapine-only: 4.72 kg, SE = 0.67). Adaptive changes were also observed for fasting glucose (F = 3.10, p = 0.046) and triglycerides (F = 8.56, p < 0.001) in the clozapine+metformin group compared with clozapine only. CONCLUSION In this large retrospective naturalistic cohort study, co-prescription of clozapine and metformin was associated with less weight gain and related metabolic dysfunction at 6 and 12 months after initiation versus clozapine alone. These findings provide evidence for the effectiveness of metformin in preventing clozapine-induced weight gain; larger randomized controlled trials are needed to confirm these results.
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Affiliation(s)
- Nicolette Stogios
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Kateryna Maksyutynska
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada
| | | | - Marcos Sanches
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Valerie Powell
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada
| | - Philip Gerretsen
- Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Ariel Graff-Guerrero
- Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Multimodal Imaging Group, Research Imaging Centre, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Araba F Chintoh
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - George Foussias
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Gary Remington
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Margaret K Hahn
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada.,Banting and Best Diabetes Centre (BBDC), University of Toronto, Toronto, Canada
| | - Sri Mahavir Agarwal
- Schizophrenia Division, Centre for Addiction and Mental Health (CAMH), Toronto, Canada.,Temerty Faculty of Medicine, Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada.,Banting and Best Diabetes Centre (BBDC), University of Toronto, Toronto, Canada
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Shea L, Pesa J, Geonnotti G, Powell V, Kahn C, Peters W. Improving diversity in study participation: Patient perspectives on barriers, racial differences and the role of communities. Health Expect 2022; 25:1979-1987. [PMID: 35765232 PMCID: PMC9327876 DOI: 10.1111/hex.13554] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 05/30/2022] [Accepted: 06/07/2022] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION The lack of racial/ethnic diversity in research potentially limits the generalizability of findings to a broader population, highlighting the need for greater diversity and inclusion in clinical research. Qualitative research (i.e., focus groups) was conducted to identify (i) the potential motivators and barriers to study participation across different races and ethnicities; (ii) preferred delivery of education and information to support healthcare decision-making and the role of the community. METHODS Patient focus groups were conducted with 26 participants from the sponsor's Patient Engagement Research Councils selected through subjective sampling. Recruitment prioritized adequate representation across different race/ethnic groups. Participation was voluntary and participants underwent a confidential interview process before selection. Narrative analysis was used to identify themes and draw insights from interactions. Experienced research specialists identified emerging concepts, and these were tested against new observations. The frequency of each concept was examined to understand its importance. RESULTS Based on self-selected race/ethnicity, participants were divided into five focus groups (Groups: African American/Black: 2; Hispanic/Latino, Asian American, and white: 1 each) and were asked to share their experiences/opinions regarding the stated objectives. Barriers to study participation included: limited awareness of opportunities to participate in research, fears about changes in standard therapy, breaking cultural norms/stigma, religion-related concerns and mistrust of clinical research. Participants identified the importance of transparency by pharmaceutical companies and other entities to build trust and partnership and cited key roles that communities can play. The perceptions of the African American group regarding diversity/inclusion in research studies appeared to be different from other groups; a lack of trust in healthcare providers, concerns about historical instances of research abuse and the importance of prayer were cited. CONCLUSION This study provided insights into barriers to study participation, and also highlighted the need for pharmaceutical companies and other entities to authentically engage in strategies that build trust within communities to enhance recruitment among diverse populations. PATIENT OR PUBLIC CONTRIBUTION The data collected in the present study was provided by the participants in the focus groups.
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Affiliation(s)
- Lisa Shea
- Janssen Scientific Affairs, LLC, Titusville, New Jersey, USA
| | - Jacqueline Pesa
- Janssen Scientific Affairs, LLC, Titusville, New Jersey, USA
| | | | | | - Caryl Kahn
- CorEvitas, LLC, Waltham, Massachusetts, USA
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Elardo E, Elbadri N, Sanchez C, Powell V, Smaris M, Li Y, Jacobson J, Hilbert T, Hamilton T, Wu DW. B subgroup detection in a small hospital transfusion service. Immunohematology 2021; 37:89-94. [PMID: 34170644 DOI: 10.21307/immunohematology-2021-014] [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: 11/11/2022]
Abstract
The ABO blood group system includes phenotypes, or subgroups, that differ in the amount of A and B antigens present on the red blood cells (RBCs). These subgroups also differ in the A, B, or H substances present in secretions (for individuals who have the secretor phenotype). B subgroups are very rare and are less frequently reported than A subgroups. Usually, B subgroups are discovered during serologic testing when there is a discrepancy between RBC and serum grouping results. Subgroups of B are usually identified by a reference laboratory using molecular and adsorption-elution methods. This report details a case of a young, healthy, pregnant woman with a B subgroup detected by a small transfusion service using adsorption-elution methods. Serology and genotyping of the ABO gene was performed at a reference laboratory where the serology was consistent with a B subgroup, but no changes were identified in ABO gene sequencing. It is important to correctly identify B subgroups in donors and recipients to help resolve ABO discrepancies and potentially prevent ABO incompatibility in blood transfusion, thus minimizing transfusion reactions. The ABO blood group system includes phenotypes, or subgroups, that differ in the amount of A and B antigens present on the red blood cells (RBCs). These subgroups also differ in the A, B, or H substances present in secretions (for individuals who have the secretor phenotype). B subgroups are very rare and are less frequently reported than A subgroups. Usually, B subgroups are discovered during serologic testing when there is a discrepancy between RBC and serum grouping results. Subgroups of B are usually identified by a reference laboratory using molecular and adsorption-elution methods. This report details a case of a young, healthy, pregnant woman with a B subgroup detected by a small transfusion service using adsorption-elution methods. Serology and genotyping of the ABO gene was performed at a reference laboratory where the serology was consistent with a B subgroup, but no changes were identified in ABO gene sequencing. It is important to correctly identify B subgroups in donors and recipients to help resolve ABO discrepancies and potentially prevent ABO incompatibility in blood transfusion, thus minimizing transfusion reactions.
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Affiliation(s)
- E Elardo
- Department of Pathology and Laboratories , NYU Langone Hospital-Brooklyn, 150 55th Street, Brooklyn , NY 11220
| | - N Elbadri
- Department of Pathology and Laboratories , NYU Langone Hospital-Brooklyn, Brooklyn , NY
| | - C Sanchez
- Department of Pathology and Laboratories , NYU Langone Hospital-Brooklyn, Brooklyn , NY
| | - V Powell
- Transfusion Services, Department of Pathology and Laboratories , NYU Langone Hospital-Tisch, New York , NY
| | - M Smaris
- Department of Pathology and Laboratories , NYU Langone Hospital-Brooklyn, Brooklyn , NY
| | - Y Li
- Clinical Laboratories, Perlmutter Cancer Center , Lake Success, Huntington, Rego Park, and NYU Langone Health, New York , NY
| | - J Jacobson
- Department of Pathology and Laboratories , Bellevue Hospital, New York , NY
| | - T Hilbert
- Transfusion Services, Department of Pathology and Laboratories , NYU Langone Hospital-Tisch, New York , NY
| | - T Hamilton
- Transfusion Services, Department of Pathology and Laboratories , NYU Langone Hospital-Tisch, New York , NY
| | - D W Wu
- Department of Pathology and Laboratories , NYU Langone Hospital-Brooklyn, Brooklyn , NY
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Affiliation(s)
- Gary Remington
- From the Centre of Addiction and Mental Health (CAMH) (Remington, Powell); the Campbell Family Mental Health Research Institute, CAMH (Remington); the Department of Psychiatry, University of Toronto (Remington); and the Graduate Department of Psychological Clinical Science, University of Toronto- Scarborough (Remington), Toronto, Ont., Canada
| | - Valerie Powell
- From the Centre of Addiction and Mental Health (CAMH) (Remington, Powell); the Campbell Family Mental Health Research Institute, CAMH (Remington); the Department of Psychiatry, University of Toronto (Remington); and the Graduate Department of Psychological Clinical Science, University of Toronto- Scarborough (Remington), Toronto, Ont., Canada
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6
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Takeuchi H, Powell V, Geisler S, DeSanti M, Fervaha G, Agid O, Kane JM, Remington G. Clozapine administration in clinical practice: once-daily versus divided dosing. Acta Psychiatr Scand 2016; 134:234-40. [PMID: 27182769 DOI: 10.1111/acps.12593] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [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] [Accepted: 04/25/2016] [Indexed: 12/22/2022]
Abstract
OBJECTIVE While it is recommended that clozapine be administered in a divided dosing regimen, it is unclear whether this recommendation is followed in real-world clinical practice. In two large datasets, we examined clozapine dosing frequency and patient characteristics across different dosing regimens. METHOD We conducted a cross-sectional survey, collecting data on patients receiving clozapine in August/September 2015 from the Centre for Addiction and Mental Health (CAMH) in Toronto, Canada, and The Zucker Hillside Hospital (ZHH) in New York, United States. RESULTS Of 676 and 308 patients included in CAMH and ZHH datasets, clozapine was prescribed once daily in 75.1% and 74.4%, even though doses exceeding 200 mg/day were administered in 88.6% and 84.4% of the respective samples. No significant difference was found in the rates of positive symptom remission between once-daily vs. divided dosing (79.7% vs. 80.5%, P = 1.00). Higher clozapine dose and use of anticholinergic medications were significantly associated with divided dosing in both datasets. Older age or male gender was related to divided dosing in CAMH or ZHH dataset respectively. CONCLUSION Despite the product monograph recommendation, clozapine is frequently prescribed once daily in North America. Further studies are needed to compare clinical outcomes between once-daily vs. divided clozapine dosing.
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Affiliation(s)
- H Takeuchi
- Schizophrenia Division, Complex Mental Illness Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - V Powell
- Schizophrenia Division, Complex Mental Illness Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - S Geisler
- Department of Psychiatry, Zucker Hillside Hospital, Northwell Health, Glen Oaks, NY, USA
| | - M DeSanti
- Schizophrenia Division, Complex Mental Illness Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - G Fervaha
- Schizophrenia Division, Complex Mental Illness Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada
| | - O Agid
- Schizophrenia Division, Complex Mental Illness Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada
| | - J M Kane
- Department of Psychiatry, Zucker Hillside Hospital, Northwell Health, Glen Oaks, NY, USA.,Department of Psychiatry, Hofstra Northwell School of Medicine, Hempstead, NY, USA
| | - G Remington
- Schizophrenia Division, Complex Mental Illness Program, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
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Remington G, Lee J, Agid O, Takeuchi H, Foussias G, Hahn M, Fervaha G, Burton L, Powell V. Clozapine’s critical role in treatment resistant schizophrenia: ensuring both safety and use. Expert Opin Drug Saf 2016; 15:1193-203. [DOI: 10.1080/14740338.2016.1191468] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- G. Remington
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - J. Lee
- Department of General Psychiatry 1, Institute of Mental Health, Singapore, Singapore
| | - O. Agid
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - H. Takeuchi
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - G. Foussias
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - M. Hahn
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - G. Fervaha
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - L. Burton
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - V. Powell
- Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
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Lee J, Bies R, Takeuchi H, Fervaha G, Bhaloo A, Powell V, Remington G. Quantifying intraindividual variations in plasma clozapine levels: a population pharmacokinetic approach. J Clin Psychiatry 2016; 77:681-7. [PMID: 27136679 DOI: 10.4088/jcp.14m09714] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 05/19/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Clozapine has strong recommendations for therapeutic drug monitoring. While factors that influence interindividual variation in plasma clozapine levels have been extensively reported, intraindividual variation remains poorly studied. We employed a population pharmacokinetic approach to assess intraindividual variations in plasma levels of both clozapine and N-desmethylclozapine, as well as the impact of smoking on this variability. METHODS Patients who were initiated on clozapine from January 2009 to December 2010 and who provided at least 2 plasma samples were included in this study. The observed concentrations of clozapine and N-desmethylclozapine were applied in a Bayesian pharmacokinetic modeling approach by using a previously published pharmacokinetic model from an independent sample to compute a predicted concentration. The predicted concentrations of clozapine and N-desmethylclozapine were then compared with the observed concentrations in the form of a ratio: predicted-to-observed concentration ratio (Cpred/Cobs). The coefficient of variation of the Cpred/Cobs ratios was taken as a measure of intraindividual variation. RESULTS A total of 723 plasma levels from 61 patients were included in this analysis. The coefficient of variation of Cpred/Cobs ratios for clozapine and N-desmethylclozapine were 29.8% (SD = 17.2%) and 27.4% (SD = 16.4%), respectively. Though values were higher, smoking did not have a significant effect on coefficients of variation of clozapine (33.5% vs 26.3%, P = .184) or N-desmethylclozapine (30.7% vs 24.2%, P = .100). CONCLUSIONS Clinicians need to be aware of intraindividual variability and not assume that plasma levels are static. If plasma levels are used to guide dosing of clozapine, serial measurements rather than a single level might be necessary to make an informed clinical decision. The clinical implications of intraindividual variability in plasma clozapine levels need further study.
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Affiliation(s)
- Jimmy Lee
- Schizophrenia Division, Centre for Addiction and Mental Health, 250 College St, Toronto, Ontario M5T 1R8, Canada
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Abstract
OBJECTIVE Clozapine's association with agranulocytosis led to the implementation of stringent and mandatory hematologic monitoring guidelines in most countries. Although other hematologic aberrations such as eosinophilia and neutropenia have been previously described, clozapine's impact on the erythroid lineage has not been studied. There is a suspicion that a higher rate of anemia is observed in patients receiving clozapine; therefore, we hypothesized that there would be a higher rate of anemia in patients receiving clozapine therapy. METHOD All individuals initiated on clozapine at our center from 2009 to 2010 were recruited. Information on age, gender, medical comorbidities, and smoking status was extracted from the medical records. Data from complete blood counts over a 2-year follow-up period were extracted, with anemia defined as a hemoglobin value below 120 g/L for women and 130 g/L for men. Time to anemia event was calculated and Cox regression was employed to identify predictors of anemia. RESULTS We found a high incidence of anemia in the first 2 years following clozapine initiation; of the 94 individuals (68 men, 26 women) recruited, 23 (24.5%) developed anemia. Higher baseline hemoglobin level (hazard ratio [HR] = 0.86, P = .002) and smoking status (HR = 0.21, P = .021) were identified as significant protective factors against anemia in men but not in women (HR = 0.92, P = .184, and HR = 0.52, P = .467 for baseline hemoglobin and smoking, respectively). CONCLUSIONS Although smoking appears to lower the risk of anemia, we believe this is due to smoking's up-regulation of hemoglobin levels. Further studies are warranted in light of the present findings; for example, we cannot exclude the possibility that anemia was an epiphenomenon, characterizing instead a population with severe mental illness.
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Affiliation(s)
- Jimmy Lee
- Schizophrenia Division, Centre for Addiction and Mental Health, 25 College St, Toronto, Ontario M5T 1R8
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10
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Syms J, Powell V, Tajirian T. IMPLEMENTATION OF CLOZAPINE MYOCARDITIS MONITORING IN HOSPITAL INPATIENTS. Can J Cardiol 2015. [DOI: 10.1016/j.cjca.2015.07.116] [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: 10/22/2022] Open
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Smith CF, Gavaghan BJ, McSweeney D, Powell V, Lisle A. Comparison of the measurement of heart rate in adult free-range chickens (Gallus domesticus) by auscultation and electrocardiography. Aust Vet J 2014; 92:509-11. [PMID: 25294609 DOI: 10.1111/avj.12254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2014] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To compare the heart rates of adult free-range chickens (Gallus domesticus) measured by auscultation with a stethoscope with those measured simultaneously using electrocardiography (ECG). METHODS With each bird in a standing position, estimation of the heart rate was performed by placing a mark on paper for every 4 beats for roosters and 8 beats for hens as detected by auscultation over 30 s, while simultaneous ECG was performed. RESULTS Heart rates measured by auscultation showed a high correlation (r = 0.97) with those measured by ECG. CONCLUSION There was a high correlation between the heart rates of adult free-range chickens measured by auscultation with a stethoscope and those measured simultaneously using ECG.
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Affiliation(s)
- C F Smith
- School of Agriculture and Food Sciences, University of Queensland, Gatton, QLD, Australia
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Lee J, Takeuchi H, Fervaha G, Bhaloo A, Powell V, Remington G. Relationship between clinical improvement and functional gains with clozapine in schizophrenia. Eur Neuropsychopharmacol 2014; 24:1622-9. [PMID: 25156578 DOI: 10.1016/j.euroneuro.2014.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 07/31/2014] [Accepted: 08/02/2014] [Indexed: 11/26/2022]
Abstract
Impairment in psychosocial functioning is a key feature in schizophrenia, but few studies have examined the relationship between improvements in symptoms and functioning. We examined the relationship between change in symptoms and change in functioning in a group of patients with treatment-resistant schizophrenia after 6 and 12 weeks of clozapine treatment. Participants were assessed prior to clozapine and again at 6 and 12-week on the 18-item Brief Psychiatric Rating Scale (BPRS) and the Social and Occupational Functioning Scale (SOFAS). Change scores in BPRS and SOFAS at 6 and 12-week post-clozapine were calculated and the direct relationship was assessed via regression models. Forty-three participants were included in this study; age of sample was 42.1 ± 12.7 years, with 31 (72.1%) male participants. At baseline, the mean BPRS total and SOFAS scores were 46.98 ± 12.86 and 33.07 ± 10.79, respectively. There were significant improvements in BPRS total and SOFAS scores at 6 weeks, but no significant differences between 6 and 12-week assessments. There was no significant change in negative symptoms at both follow-up assessments. At 6-week, change in symptoms was not correlated with change in functioning and while the relationship between change in symptoms and functioning was stronger at 12 weeks, none of the BPRS factors emerged as a significant predictor. The present study found that lower baseline SOFAS score was the most robust predictor for improvements in SOFAS at 6 and 12-weeks. There appears to be a "ceiling" for functional improvements on clozapine, but follow-up studies are needed to examine functional gains beyond 12 weeks.
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Affiliation(s)
- Jimmy Lee
- Department of General Psychiatry 1, Institute of Mental Health, Singapore; Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore; Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada.
| | - Hiroyoshi Takeuchi
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Keio University, School of Medicine, Department of Neuropsychiatry, Tokyo, Japan
| | - Gagan Fervaha
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Canada
| | - Amaal Bhaloo
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada
| | - Valerie Powell
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada
| | - Gary Remington
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Canada; Department of Psychiatry, University of Toronto, Canada
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Lee J, Powell V, Remington G. Mean platelet volume in schizophrenia unaltered after 1year of clozapine exposure. Schizophr Res 2014; 157:134-6. [PMID: 24906221 DOI: 10.1016/j.schres.2014.04.038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/22/2014] [Accepted: 04/26/2014] [Indexed: 11/26/2022]
Abstract
This study investigated the MPV of patients with major psychoses before and after 1year of clozapine exposure. Data were obtained from chart reviews of patients who were initiated on clozapine at the Centre of Addiction and Mental Health (CAMH) in Toronto. 100 patients were eligible for this study; 65 remained on clozapine after 1year. Prior to clozapine initiation, MPV was 10.79±0.91fL and there was no difference in MPV after 1year of clozapine exposure (p=0.777). We found high MPV in patients with schizophrenia and related psychoses, which was unaltered after 1year of clozapine treatment.
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Affiliation(s)
- Jimmy Lee
- Department of General Psychiatry 1, Institute of Mental Health, Singapore, Singapore; Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore, Singapore; Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.
| | - Valerie Powell
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Gary Remington
- Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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Guenette MD, Powell V, Johnston K, Foussias G, Agid O, Hahn M, Takeuchi H, Remington G. Risk of neutropenia in a clozapine-treated elderly population. Schizophr Res 2013; 148:183-5. [PMID: 23727216 DOI: 10.1016/j.schres.2013.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 10/26/2022]
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Powell V, Din FM, Acharya A, Torres-Urquidy MH. Broader Considerations of Medical and Dental Data Integration. Health Informatics 2012. [PMCID: PMC7177026 DOI: 10.1007/978-1-4471-2185-5_4] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Valerie Powell
- Robert Morris University, Moon Township,, Moon Township, 15108-1189 USA
| | - Franklin M. Din
- Medical Informatics Center of Excellence, Camp Hill, 25403 USA
| | - Amit Acharya
- MCRF/BIRC, Marshfield, WI, USA, Marshfield, 54449 Wisconsin USA
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Sockalingam S, Shammi C, Powell V, Barker L, Remington G. Determining rates of hepatitis C in a clozapine treated cohort. Schizophr Res 2010; 124:86-90. [PMID: 20605572 DOI: 10.1016/j.schres.2010.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 06/02/2010] [Accepted: 06/07/2010] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To determine the prevalence rates of hepatitis C in patients with schizophrenia and schizoaffective disorder being treated with clozapine. METHODS Clozapine-treated outpatients and inpatients were recruited from the Centre for Addiction and Mental Health Schizophrenia Program in Toronto, Canada. All subjects had liver function tests, and positive HCV status was defined as a positive qualitative HCV RNA assay. Subjects completed a self-report questionnaire assessing HCV risk factors, past history of liver disease, previous diagnosis of human immunodeficiency virus (HIV), past hepatitis B virus (HBV) infection and current alcohol use. RESULTS 110 subjects participated in the study and the HCV prevalence rate (antibody and viremia-positive) was 2.7%, compared to a 0.8% prevalence rate in Canada. All study subjects had established housing, none reported a history of HIV, and only one patient had a history of HBV infection. A total of 9% drank two or more drinks on a typical day drinking and 7% endorsed having six or more drinks on one occasion at least monthly. Two of 3HCV-viremia positive subjects had HCV risk factors, specifically intravenous drug use and intranasal cocaine use. There was no difference between HCV infected and HCV negative subjects on liver function tests. CONCLUSIONS Our study demonstrates elevated rates of HCV in clozapine-treated patients compared to the general population in Canada and are congruent with reports from United States centres. Our study highlights the importance of homelessness and patterns of high-risk behaviour when interpreting HCV prevalence rates in this sub-population of patients and should be explored in future studies.
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Affiliation(s)
- Sanjeev Sockalingam
- Psychiatry, Health and Disease Division, University Health Network, Toronto, Ontario, Canada.
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Campbell R, Weis MA, Millet L, Powell V, Hull-Jilly D, Hackman H. From surveillance to action: early gains from the National Violent Death Reporting System. Inj Prev 2007; 12 Suppl 2:ii6-ii9. [PMID: 17170175 PMCID: PMC2563483 DOI: 10.1136/ip.2006.012450] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [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: 11/04/2022]
Abstract
OBJECTIVES Drawing from the experiences of individual state programs that currently participate in the National Violent Death Reporting System (NVDRS), this article reviews some of the practical benefits that may accrue from the introduction of violent death surveillance systems. DESIGN As a state-based surveillance system that uses multiple data sources and relies upon multiple stakeholders, the NVDRS program has fostered an array of initiatives within and among individual state programs. State-based initiatives highlighted in this article were selected on the basis of a purposive sampling strategy intended to illustrate key aspects of program development. SETTING The NVDRS state programs are in Alaska, California, Colorado, Georgia, Kentucky, Maryland, Massachusetts, New Jersey, New Mexico, North Carolina, Oklahoma, Oregon, Rhode Island, South Carolina, Utah, Virginia, and Wisconsin. RESULTS The NVDRS has helped to build alliances and collaborative efforts between key stakeholders, facilitated the recognition of violent death as a public health problem through outreach and media attention, acted as a catalyst for new projects, enhanced surveillance of special populations and utility for evaluation, and identified key circumstances that will target interventions in state prevention planning. CONCLUSIONS The NVDRS has implemented data collection efforts and is beginning to produce and analyze findings. In the process of implementing the data collection system and publicizing findings, state NVDRS programs are realizing other gains that strengthen their surveillance efforts. The use of data for prevention purposes will be the ultimate indicator of program success.
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Affiliation(s)
- R Campbell
- Massachusetts Department of Public Health, Injury Surveillance Program, Boston, MA 02108-4619, USA.
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Powell V, Barber CW, Hedegaard H, Hempstead K, Hull-Jilly D, Shen X, Thorpe GE, Weis MA. Using NVDRS data for suicide prevention: promising practices in seven states. Inj Prev 2007; 12 Suppl 2:ii28-ii32. [PMID: 17170167 PMCID: PMC2563480 DOI: 10.1136/ip.2006.012443] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [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: 11/04/2022]
Abstract
OBJECTIVES This article describes how seven states participating in a new public health surveillance system for violent death in the US, the National Violent Death Reporting System (NVDRS), have used data to support local suicide prevention activities. SETTING The NVDRS is unique in that it augments death certificate data with event and circumstance information from death investigation reports filed by coroners, medical examiners, and law enforcement. These data illuminate why the victim ended his or her life, fatal injury patterns, and toxicological findings at death. RESULTS Current suicide prevention efforts using these data fall into three categories: describing the problem of suicide and identifying opportunities for intervention; collaborating on statewide suicide prevention plans; and forming new partnerships for targeted prevention initiatives. Taken together, these three areas show early promise for state suicide prevention efforts. CONCLUSIONS In each of the states, NVDRS data analyses are being shared with injury prevention colleagues, suicide prevention planning groups and policymakers, and adapted to respond to unique state and local suicide problems. A powerful surveillance tool, the NVDRS is bringing new clarity and direction to these state-based efforts. The NVDRS can serve as a model for other countries looking to establish timely suicide surveillance systems and data driven prevention strategies.
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Affiliation(s)
- V Powell
- Office of the Chief Medical Examiner, Virginia Department of Health, Richmond, VA 23219, USA.
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Powell V, Steel CH. Search for the woolly mammoth: a case study in inquiry-based learning. J Vet Med Educ 2003; 30:254-257. [PMID: 14648499 DOI: 10.3138/jvme.30.3.254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Affiliation(s)
- V Powell
- School of Animal Studies, Faculty of Natural Resources, Agriculture and Veterinary Science, University of Queensland, Australia.
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Abstract
BACKGROUND The Sl(a) (Knops system) located on complement receptor 1 (CR1) has been associated with malarial rosetting, a process associated with severe malarial infections. Moreover, the long homologous repeats (LHRs) B and C of CR1 were implicated in rosette formation. As a step toward mapping the location of Knops system antigens, truncated CR1 proteins have been expressed and their ability to inhibit antibodies to the high-incidence Knops system antigens was assessed. STUDY DESIGN AND METHODS Individual LHRs (A, B, C, and D) of CR1 of the common CR1*1 (F) allotype were expressed as secreted forms in 293T cells. Their abilities to specifically neutralize Knops system antibodies were tested by both hemagglutination and flow cytometry. RESULTS Three examples of anti-Kn(a) (n = 6) were almost completely inhibited by LHR-C and three by LHR-D. Two examples of anti-McC(a) (n = 2) and seven examples of anti-Sl(a) (n = 8) were inhibited by LHR-D. Both examples of anti-Yk(a) (n = 2) were partially inhibited by LHR-D. CONCLUSION The high-incidence Knops system antigens reside within LHR-D and to a lesser extent within LHR-C. Because of the role of Sl(a) antigen in malaria rosetting, these results indicate that LHR-D may represent an additional malaria interaction region in CR1.
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Affiliation(s)
- D Tamasauskas
- Immunochemistry Laboratory, New York Blood Center, New York, New York 10021, USA
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Abstract
Genetic variations in the CC chemokine receptor (CCR5) leading to reduced or absent expression are associated with resistance to human immunodeficiency virus infection and delayed onset of acquired immunodeficiency syndrome. Similarly, lack of the red-cell chemokine receptor Duffy confers protection against malarial infection byPlasmodium vivax. Investigators have previously described a missense mutation (R89C) in the first intracellular loop of Duffy that results in reduced protein expression. The present study shows that the lower Duffy expression is due to loss of the positive charge at this position, resulting in protein instability. Moreover, R60S, a mutation in the first intracellular loop of CCR5 noted in a recent cohort study, likewise results in reduced surface expression and function of CCR5. The presence of a homologous, naturally occurring mutation that may be protective against disease thus defines a novel mechanism accounting for the decreased expression of these receptors in some individuals.
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Affiliation(s)
- D Tamasauskas
- Immunochemistry Laboratory, New York Blood Center, 310 East 67th St., New York, NY 10021, USA
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Powell V, Leroux BG, Martin JA, White BA. Identification of adult populations at high risk for dental caries using a computerized database and patient records: a pilot project. J Public Health Dent 2001; 60:82-4. [PMID: 10929565 DOI: 10.1111/j.1752-7325.2000.tb03299.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The purpose of this study is to test the usefulness of dental insurance claims history, supplemented with radiographic caries diagnoses, as a means of identifying caries-active and caries-inactive working adults, as determined by bacterial levels. Computerized identification of at-risk groups may facilitate subject selection for clinical trials designed to test caries-preventive strategies. METHODS Two groups of subjects were initially selected from an insurance database based upon their dental service utilization during a one-year period: a "low restorative" group of individuals defined as persons who had received no restorative treatment, and a "high restorative" group comprised of individuals who had received at least three multisurfaced restorations. A chart review confirmed a diagnosis of caries in the high restorative group and an absence of caries in the low restorative group. Subjects were then approached for saliva collection. The low and high restorative groups were compared for salivary mutans streptococci and lactobacilli levels, stimulated flow rate, and buffer capacity (n = 48). RESULTS The high and low restorative groups differed in mutans streptococci levels, but not on other measures. CONCLUSIONS A group of subjects who had recently received multisurfaced restorations that were placed for reasons of caries had significantly higher levels of mutans streptococci and potential for continued caries activity when compared to a group of subjects who had received no restorations and were caries free.
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Affiliation(s)
- V Powell
- Department of Restorative Dentistry, University of Washington, Seattle 98195, USA.
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Keating L, Lubke C, Powell V, Young T, Souvlis T, Jull G. Mid-thoracic tenderness: a comparison of pressure pain threshold between spinal regions, in asymptomatic subjects. Man Ther 2001; 6:34-9. [PMID: 11243907 DOI: 10.1054/math.2000.0377] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Palpation for tenderness forms an important part of the manual therapy assessment for musculoskeletal dysfunction. In conjunction with other testing procedures it assists in establishing the clinical diagnosis. Tenderness in the thoracic spine has been reported in the literature as a clinical feature in musculoskeletal conditions where pain and dysfunction are located primarily in the upper quadrant. This study aimed to establish whether pressure pain thresholds (PPTs) of the mid-thoracic region of asymptomatic subjects were naturally lower than those of the cervical and lumbar areas. A within-subject study design was used to examine PPT at four spinal levels C6, T4, T6, and L4 in 50 asymptomatic volunteers. Results showed significant (P<0.001) regional differences. PPT values increased in a caudal direction. The cervical region had the lowest PPT scores, that is was the most tender. Values increased in the thoracic region and were highest in the lumbar region. This study contributes to the normative data on spinal PPT values and demonstrates that mid-thoracic tenderness relative to the cervical spine is not a normal finding in asymptomatic subjects.
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Affiliation(s)
- L Keating
- Department of Physiotherapy, The University of Queensland, Brisbane, Qld 4072, Australia
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Drysdale S, Howarth J, Powell V, Healing T. The use of cluster sampling to determine aid needs in Grozny, Chechnya in 1995. Disasters 2000; 24:217-227. [PMID: 11026155 DOI: 10.1111/1467-7717.00143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
War broke out in Chechnya in November 1994 following a three-year economic blockade. It caused widespread destruction in the capital Grozny. In April 1995 Medical Relief International--or Merlin, a British medical non-governmental organisation (NGO)--began a programme to provide medical supplies, support health centres, control communicable disease and promote preventive health-care in Grozny. In July 1995 the agency undertook a city-wide needs assessment using a modification of the cluster sampling technique developed by the Expanded Programme on Immunisation. This showed that most people had enough drinking-water, food and fuel but that provision of medical care was inadequate. The survey allowed Merlin to redirect resources earmarked for a clean water programme towards health education and improving primary health-care services. It also showed that rapid assessment by a statistically satisfactory method is both possible and useful in such a situation.
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Loizou PC, Dorman MF, Powell V. The recognition of vowels produced by men, women, boys, and girls by cochlear implant patients using a six-channel CIS processor. J Acoust Soc Am 1998; 103:1141-1149. [PMID: 9479767 DOI: 10.1121/1.421248] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Five patients who used a six-channel, continuous interleaved sampling (CIS) cochlear implant were presented vowels, in two experiments, from a large sample of men, women, boys, and girls for identification. At issue in the first experiment was whether vowels from one speaker group, i.e., men, were more identifiable than vowels from other speaker groups. At issue in the second experiment was the role of the fifth and sixth channels in the identification of vowels from the different speaker groups. It was found in experiment 1 that (i) the vowels produced by men were easier to identify than vowels produced by any of the other speaker groups, (ii) vowels from women and boys were more difficult to identify than vowels from men but less difficult than vowels from girls, and (iii) vowels from girls were more difficult to identify than vowels from all other groups. In experiment 2 removal of channels 5 and 6 from the processor impaired the identification of vowels produced by women, boys and girls but did not impair the identification of vowels produced by men. The results of experiment 1 demonstrate that scores on tests of vowels produced by men overestimate the ability of patients to recognize vowels in the broader context of multi-talker communication. The results of experiment 2 demonstrate that channels 5 and 6 become more important for vowel recognition as the second formants of the speakers increase in frequency.
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Affiliation(s)
- P C Loizou
- Department of Applied Science, University of Arkansas at Little Rock 72204-1099, USA.
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Powell V. Burnout: a nurse's perspective. Revolution 1996; 6:40-43. [PMID: 9043401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Powell V, Griffore RJ, Kallen DJ, Popovich SN. Physicians' preferences for adoption, abortion, and keeping a child among adolescents. Res Sociol Health Care 1991; 9:33-47. [PMID: 12317575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Powell V. Rotation flap. Aust Fam Physician 1990; 19:388. [PMID: 2185730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Abstract
We assessed the effect of in-hospital call on clinical performance and emotional state in seven medical interns. Clinical performance was evaluated through the use of actors who were trained to pose as patients seeking consultation because of specific medical complaints. The physician-patient interaction was scored according to predetermined criteria. There was no significant difference in interns' performance whether or not the preceding 24 hours had been spent on call. On a standardized questionnaire, interns reported significantly more fatigue and depression after call. We conclude that the major discernible effect of call is a deterioration of interns' feelings of well-being.
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Nedd KJ, Kent M, Powell V. Subarachnoid hemorrhage during pregnancy and the puerperium: report of 3 cases and review of the literature. J Am Osteopath Assoc 1986; 86:183-8. [PMID: 3700156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Sbokos CG, Salama FD, Powell V, McMillan IK. Primary fibrosarcoma of the diaphragm. Br J Dis Chest 1977; 71:49-52. [PMID: 831767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Primary tumours of the diaphragm are rare. Benign neoplasms occur more frequently than malignant ones. Among the latter, fibrosarcoma is the most common. A case of primary fibrosarcoma of the diaphragm is presented with long survival and recurrence 10 years after first surgical removal. At re-operation, a huge tumour was excised arising from a small part of the diaphragm. The histology of the recurrence was the same as the original tumour. The patient remained free of signs and symptoms nine months after the second operation.
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McDougall RS, Walters J, Gunasena D, John GE, Powell V. Reduction of skin dose in mantle fields by the use of a copper filter. Radiography (Lond) 1975; 41:115-9. [PMID: 1178832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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