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Zamuner F, Carpenter EK, Gebrekidan H, Arcos-Gómez G, Parkinson A, Cameron AWN, Leury BJ, DiGiacomo K. Successful transfer of passive immunity: the natural alternative to antibiotics for boosting the survival of intensively reared dairy goat kids. Animal 2024; 18:101040. [PMID: 38101110 DOI: 10.1016/j.animal.2023.101040] [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] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 12/17/2023] Open
Abstract
In dairy operations, antibiotics have traditionally been used to treat, prevent, and control diseases. However, given the mounting global crisis of antimicrobial resistance (AMR), farmers are urged to re-assess and reduce their reliance on antibiotics. Thus, this randomized, double-blinded cohort study aimed to estimate the prevalence of failed and successful transfer of passive immunity (FTPI and STPI) in dairy goat kids reared under commercial conditions, and the effects of antibiotic metaphylaxis on the pre-weaning (≤42 d old) mortality in FTPI and STPI kids. Plasma concentration of immunoglobulin G at 1d old (pIgG-24 h) was measured in 747 male Saanen kids for the determination of FTPI and STPI (pIgG-24 h < 12 and ≥12 g/L, respectively). Kids were then randomly divided into two groups: those receiving a single penicillin injection at 1 d old (PEN), and those receiving no treatment (CTR). The mean (±SD) pIgG-24 h and initial BW (IBW) were 17 ± 9.8 g/L and 4.1 ± 0.64 kg. The prevalence of FTPI was 29% (220/747 kids). Gastrointestinal complications were the primary cause of death (41%), followed by septicemia (22%) and arthritis (17%). A single penicillin injection reduced preweaning mortality by 55% (10 vs 22%, PEN vs CTR). However, results suggest that such a decline was mainly driven by the improved survival rates among FTPI kids, which increased by 19% (from 62% in CTR-FTPI to 82% in PEN-FTPI), as opposed to an 8% increase among STPI kids (from 85% in CTR-STPI to 93% in PEN-STPI). Additionally, the odds of mortality ≤ 42 d old were threefold higher in the CTR-FTPI group when compared to both the CTR-STPI and PEN-FTPI groups, suggesting a potential parity between STPI and PEN for mortality rate reduction. Taken together, the results indicate that although metaphylactic antibiotics can halve preweaning mortality, similar improvements are likely to be achieved via increased STPI rates. Furthermore, by targeting metaphylactic interventions to high-risk groups (i.e., those displaying signs of inadequate colostrum intake and/or low birth BW), farmers could reduce treatment costs and mitigate AMR risks. While these findings carry considerable weight for commercial dairy goat practices, their applicability to other systems (i.e., extensive, semi-intensive, mohair, meat systems) warrants further investigation.
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Affiliation(s)
- F Zamuner
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science - The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - E K Carpenter
- Meredith Dairy Pty Ltd., 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - H Gebrekidan
- Meredith Dairy Pty Ltd., 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - G Arcos-Gómez
- Meredith Dairy Pty Ltd., 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - A Parkinson
- Meredith Dairy Pty Ltd., 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - A W N Cameron
- Meredith Dairy Pty Ltd., 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - B J Leury
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science - The University of Melbourne, Parkville, Victoria 3010, Australia
| | - K DiGiacomo
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science - The University of Melbourne, Parkville, Victoria 3010, Australia
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Parkinson A, Mullan B, Bebbington K, Davis E, Treadgold C, Finlay-Jones A. Wellbeing and distress in young people with chronic conditions: how do positive psychology variables relate to mental health outcomes? Health Psychol Behav Med 2023; 11:2274539. [PMID: 37941791 PMCID: PMC10629415 DOI: 10.1080/21642850.2023.2274539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 10/17/2023] [Indexed: 11/10/2023] Open
Abstract
Objective The aim of this study was to determine the unique and shared contributions of various positive psychology constructs (gratitude, optimism, hope, self-compassion, self-efficacy, and emotion regulation) to wellbeing and distress outcomes in young people living with a diverse range of chronic health conditions. Methods and Measures 169 Australians (84.0% female, mean age = 21.2) who reported living with a chronic physical condition completed a cross-sectional survey assessing wellbeing, distress, and each positive psychology variable. Two multiple regressions were used to determine the unique and shared contributions of the positive psychology variables to wellbeing and distress outcomes. Results When considered alongside symptom severity, the variables explained 53.4% and 38.1% of variance in distress and wellbeing, respectively. Only optimism and self-efficacy accounted for unique and significant variance in the model predicting wellbeing, accounting for 6.1% and 4.6% of unique variance, respectively. For the distress model, optimism, self-compassion, and emotion regulation each accounted for significant variance. When considered alongside other variables, hope and gratitude did not contribute to either model. Conclusion Findings suggest that individual positive psychology variables differentially contribute to wellbeing and distress outcomes in young people with chronic conditions. Optimism appears to account for unique variance in both outcomes, suggesting it may be a parsimonious target to promote complete mental health in this population.
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Affiliation(s)
- Asha Parkinson
- Telethon Kids Institute, Nedlands, Australia
- enAble Institute, School of Population Health, Curtin University, Bentley, Australia
| | - Barbara Mullan
- enAble Institute, School of Population Health, Curtin University, Bentley, Australia
- WACPRU, School of Population Health, Curtin University, Bentley, Australia
| | - Keely Bebbington
- Children’s Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- Centre for Child Health Research, University of Western Australia, Perth, Australia
| | - Elizabeth Davis
- Children’s Diabetes Centre, Telethon Kids Institute, The University of Western Australia, Perth, Australia
- Department of Endocrinology and Diabetes, Perth Children’s Hospital, Perth, Australia
- Division of Paediatrics, Medical School, The University of Western Australia, Perth, Australia
| | - Claire Treadgold
- Starlight Children’s Foundation, Naremburn, NSW, USA
- Discipline of Paediatrics & Child Health, UNSW, Medicine & Health, University of New South Wales, Sydney, NSW, USA
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Zamuner F, Carpenter EK, Arcos-Gómez G, Parkinson A, Cameron AWN, Leury BJ, DiGiacomo K. Evaluation of plasma immunoglobulin G and BW thresholds for predicting preweaning mortality in commercially raised dairy goat kids. Animal 2023; 17:100989. [PMID: 37801924 DOI: 10.1016/j.animal.2023.100989] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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] [Received: 05/29/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 10/08/2023] Open
Abstract
The high preweaning mortality rate is a concerning issue for the commercial dairy industry. In this context, early identification of at-risk individuals can be instrumental. To address this, we conducted a prospective cohort study with the objective of evaluating plasma immunoglobulin G concentration (pIgG-24 h) and initial BW (IBW) measured at 1d old in 363 male dairy kids (Saanen) for predicting preweaning mortality under commercial conditions. Receiver operator characteristic (ROC) analysis was used to determine critical thresholds for pIgG-24 h and IBW. Subsequently, areas under the curve (AUC), sensitivity (Se), and specificity (Sp) were examined to assess the accuracy of these thresholds. Multivariable regressions were used to model odds ratios (OR) for mortality, controlling for confounding effects between IBW and pIgG-24 h. The mean (±SD) pIgG-24 h and IBW were 16.4 ± 9.37 g/L and 4.0 ± 0.61 kg. Overall mortality ≤ 14d and ≤42d old was 12% and 21%, respectively. Critical pIgG-24 h thresholds predicting mortality ≤ 14 d and ≤42 d old were < 10.1 g/L (AUC = 0.74, Se = 59%, and Sp = 82%) and <11.4 g/L (AUC 0.70, Se = 53%, and Sp = 77%), respectively. Kids with pIgG-24 h < 10.1 g/L were six times more likely to die ≤ 14 d old [OR; 95% CI (6; 3-12)], and kids with pIgG-24 h < 11.4 g/L were four times more likely to die ≤ 42 d old (4; 2-6). The IBW threshold most linked to mortality ≤ 14 d was <3.95 kg (AUC 0.60, Se = 59%, and Sp = 61%). However, this association became inconclusive after adjusting for pIgG-24 h differences. Conversely, an IBW of <3.0 kg was associated with notably higher mortality odds within both 14 and 42 d, irrespective of pIgG-24 h levels (10; 3-37, and 4; 1-20, respectively), suggesting that kids with an IBW < 3.0 kg face an increased likelihood of dying before 42 d, irrespectively of their IgG levels. While our findings suggest pIgG-24 h < 11.4 g/L and IBW < 3.0 kg as strong indicators of early mortality risks in male dairy kids, these results require further validation for other systems.
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Affiliation(s)
- F Zamuner
- Faculty of Science - The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - E K Carpenter
- Meredith Dairy Pty Ltd, 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - G Arcos-Gómez
- Meredith Dairy Pty Ltd, 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - A Parkinson
- Meredith Dairy Pty Ltd, 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - A W N Cameron
- Meredith Dairy Pty Ltd, 106 Cameron Rd, Meredith, Victoria 3333, Australia
| | - B J Leury
- Faculty of Science - The University of Melbourne, Parkville, Victoria 3010, Australia
| | - K DiGiacomo
- Faculty of Science - The University of Melbourne, Parkville, Victoria 3010, Australia
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Finlay-Jones AL, Parkinson A, Sirois F, Perry Y, Boyes M, Rees CS. Web-Based Self-Compassion Training to Improve the Well-Being of Youth With Chronic Medical Conditions: Randomized Controlled Trial. J Med Internet Res 2023; 25:e44016. [PMID: 37703081 PMCID: PMC10534292 DOI: 10.2196/44016] [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] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 06/04/2023] [Accepted: 06/26/2023] [Indexed: 09/14/2023] Open
Abstract
BACKGROUND Up to one-third of young people live with chronic physical conditions (eg, diabetes, asthma, and autoimmune disease) that frequently involve recurrent pain, fatigue, activity limitations, stigma, and isolation. These issues may be exacerbated as young people transition through adolescence. Accordingly, young people with chronic illness are at a high risk of psychological distress. Accessible, evidence-based interventions for young people with chronic illnesses are urgently needed to improve well-being, support adaptation, and enhance daily functioning. Self-compassion, which is an adaptive means of relating to oneself during times of difficulty, is a promising intervention target for this population. OBJECTIVE This study aims to test the efficacy of a 4-week, self-guided, web-based self-compassion training program for improving well-being among young Australians (aged 16-25 years) living with a chronic medical condition. The primary outcomes were self-compassion, emotion regulation difficulties, and coping; the secondary outcomes were well-being, distress, and quality of life. We also sought to test whether changes in primary outcomes mediated changes in secondary outcomes and gather feedback about the strengths and limitations of the program. METHODS We conducted a single-blind, parallel-group, randomized controlled trial comparing a 4-week, fully automated, web-based self-compassion training program with a waitlist control. Participants were recruited via the internet, and outcomes were self-assessed at 4 (T1) and 12 weeks (T2) after the baseline time point via a web-based survey. A mixed methods approach was used to evaluate the program feedback. RESULTS Overall, 151 patients (age: mean 21.15, SD 2.77 years; female patients: n=132, 87.4%) were randomized to the intervention (n=76, 50.3%) and control (n=75, 49.7%) groups. The loss-to-follow-up rate was 47.4%, and program use statistics indicated that only 29% (22/76) of young people in the experimental group completed 100% of the program. The main reported barrier to completion was a lack of time. As anticipated, treatment effects were observed for self-compassion (P=.01; partial η2=0.05; small effect); well-being (P≤.001; partial η2=0.07; medium effect); and distress (P=.003; partial η2=0.054; small-medium effect) at the posttest time point and maintained at follow-up. Contrary to our hypotheses, no intervention effects were observed for emotion regulation difficulties or maladaptive coping strategies. Improvements in adaptive coping were observed at the posttest time point but were not maintained at follow-up. Self-compassion, but not emotion regulation difficulties or coping, mediated the improvements in well-being. CONCLUSIONS Minimal-contact, web-based self-compassion training can confer mental health benefits on young people with chronic conditions. This group experiences substantial challenges to participation in mental health supports, and program engagement and retention in this trial were suboptimal. Future work should focus on refining the program content, engagement, and delivery to optimize engagement and treatment outcomes for the target group. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry 12619000572167; https://tinyurl.com/5n6hevt. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) RR2-10.1186/s12889-020-8226-7.
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Affiliation(s)
- Amy Louise Finlay-Jones
- Youth Mental Health Team, Telethon Kids Institute, Nedlands, Australia
- School of Population Health, Curtin University, Bentley, Australia
- School of Medicine, University of Western Australia, Crawley, Australia
| | - Asha Parkinson
- Youth Mental Health Team, Telethon Kids Institute, Nedlands, Australia
- School of Population Health, Curtin University, Bentley, Australia
| | - Fuschia Sirois
- Department of Psychology, Durham University, Durham, United Kingdom
| | - Yael Perry
- Youth Mental Health Team, Telethon Kids Institute, Nedlands, Australia
- School of Medicine, University of Western Australia, Crawley, Australia
| | - Mark Boyes
- School of Population Health, Curtin University, Bentley, Australia
| | - Clare S Rees
- School of Population Health, Curtin University, Bentley, Australia
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Finlay-Jones A, Sampson R, Parkinson A, Prentice K, Bebbington K, Treadgold C, Frank B, Bates A, Freeman J, Lucas J, Dart J, Davis E, Lingam R, McKenzie A. Priority setting for children and young people with chronic conditions and disabilities. Health Expect 2023. [PMID: 37078632 DOI: 10.1111/hex.13761] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/21/2023] Open
Abstract
BACKGROUND The aim of this project was to identify the top 10 priorities for childhood chronic conditions and disability (CCD) research from the perspectives of children and young people with lived experience, their parents and caregivers and the professionals who work with them. METHODS We conducted a three-stage study based on the James Lind Alliance priority-setting partnership methods. It comprised two online surveys (n = 200; n = 201) and a consensus workshop (n = 21) with these three stakeholder groups in Australia. RESULTS In the first stage, 456 responses were submitted, which were coded and collapsed into 40 overarching themes. In the second stage, 20 themes were shortlisted, which were further refined in stage 3, before the top 10 priorities being selected. Of these, the top three priorities were improving awareness and inclusion in all aspects of their life (school, work and social relationships), improving access to treatments and support and improving the process of diagnosis. CONCLUSIONS The top 10 priorities identified reflect the need to focus on the individual, health systems and social aspects of the CCD experience when conducting research in this area. PATIENT OR PUBLIC CONTRIBUTION This study was guided by three Advisory Groups, comprising (1) young people living with CCD; (2) parents and caregivers of a child or young person with CCD and (3) professionals working with children and young people with CCD. These groups met several times across the course of the project and provided input into study aims, materials, methods and data interpretation and reporting. Additionally, the lead author and seven members of the author group have lived and experienced CCD.
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Affiliation(s)
- Amy Finlay-Jones
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
- School of Population Health, Curtin University, Perth, Western Australia, Australia
- Medical School, University of Western Australia, Perth, Western Australia, Australia
| | - Rebecca Sampson
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
- School of Population Health, Curtin University, Perth, Western Australia, Australia
| | - Asha Parkinson
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
- School of Population Health, Curtin University, Perth, Western Australia, Australia
| | - Karina Prentice
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Keely Bebbington
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Claire Treadgold
- Starlight Children's Foundation, Naremburn, New South Wales, Australia
- University of New South Wales, Sydney, New South Wales, Australia
| | - Belinda Frank
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Amber Bates
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
- Tiny Sparks WA, West Leederville, Western Australia, Australia
| | - Jacinta Freeman
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Jayden Lucas
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Julie Dart
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
- Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Elizabeth Davis
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
- Medical School, University of Western Australia, Perth, Western Australia, Australia
- Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Raghu Lingam
- University of New South Wales, Sydney, New South Wales, Australia
| | - Anne McKenzie
- Early Neurodevelopment and Mental Health, Telethon Kids Institute, Nedlands, Western Australia, Australia
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Hayes AG, Corlies P, Tate C, Barrington M, Bell JF, Maki JN, Caplinger M, Ravine M, Kinch KM, Herkenhoff K, Horgan B, Johnson J, Lemmon M, Paar G, Rice MS, Jensen E, Kubacki TM, Cloutis E, Deen R, Ehlmann BL, Lakdawalla E, Sullivan R, Winhold A, Parkinson A, Bailey Z, van Beek J, Caballo-Perucha P, Cisneros E, Dixon D, Donaldson C, Jensen OB, Kuik J, Lapo K, Magee A, Merusi M, Mollerup J, Scudder N, Seeger C, Stanish E, Starr M, Thompson M, Turenne N, Winchell K. Pre-Flight Calibration of the Mars 2020 Rover Mastcam Zoom (Mastcam-Z) Multispectral, Stereoscopic Imager. Space Sci Rev 2021; 217:29. [PMID: 33678912 PMCID: PMC7892537 DOI: 10.1007/s11214-021-00795-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 01/12/2021] [Indexed: 05/28/2023]
Abstract
UNLABELLED The NASA Perseverance rover Mast Camera Zoom (Mastcam-Z) system is a pair of zoomable, focusable, multi-spectral, and color charge-coupled device (CCD) cameras mounted on top of a 1.7 m Remote Sensing Mast, along with associated electronics and two calibration targets. The cameras contain identical optical assemblies that can range in focal length from 26 mm ( 25.5 ∘ × 19.1 ∘ FOV ) to 110 mm ( 6.2 ∘ × 4.2 ∘ FOV ) and will acquire data at pixel scales of 148-540 μm at a range of 2 m and 7.4-27 cm at 1 km. The cameras are mounted on the rover's mast with a stereo baseline of 24.3 ± 0.1 cm and a toe-in angle of 1.17 ± 0.03 ∘ (per camera). Each camera uses a Kodak KAI-2020 CCD with 1600 × 1200 active pixels and an 8 position filter wheel that contains an IR-cutoff filter for color imaging through the detectors' Bayer-pattern filters, a neutral density (ND) solar filter for imaging the sun, and 6 narrow-band geology filters (16 total filters). An associated Digital Electronics Assembly provides command data interfaces to the rover, 11-to-8 bit companding, and JPEG compression capabilities. Herein, we describe pre-flight calibration of the Mastcam-Z instrument and characterize its radiometric and geometric behavior. Between April 26 t h and May 9 t h , 2019, ∼45,000 images were acquired during stand-alone calibration at Malin Space Science Systems (MSSS) in San Diego, CA. Additional data were acquired during Assembly Test and Launch Operations (ATLO) at the Jet Propulsion Laboratory and Kennedy Space Center. Results of the radiometric calibration validate a 5% absolute radiometric accuracy when using camera state parameters investigated during testing. When observing using camera state parameters not interrogated during calibration (e.g., non-canonical zoom positions), we conservatively estimate the absolute uncertainty to be < 10 % . Image quality, measured via the amplitude of the Modulation Transfer Function (MTF) at Nyquist sampling (0.35 line pairs per pixel), shows MTF Nyquist = 0.26 - 0.50 across all zoom, focus, and filter positions, exceeding the > 0.2 design requirement. We discuss lessons learned from calibration and suggest tactical strategies that will optimize the quality of science data acquired during operation at Mars. While most results matched expectations, some surprises were discovered, such as a strong wavelength and temperature dependence on the radiometric coefficients and a scene-dependent dynamic component to the zero-exposure bias frames. Calibration results and derived accuracies were validated using a Geoboard target consisting of well-characterized geologic samples. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11214-021-00795-x.
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Affiliation(s)
- Alexander G. Hayes
- Department of Astronomy, Cornell University, Ithaca, NY 14850 USA
- Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14850 USA
| | - P. Corlies
- Department of Astronomy, Cornell University, Ithaca, NY 14850 USA
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - C. Tate
- Department of Astronomy, Cornell University, Ithaca, NY 14850 USA
| | - M. Barrington
- Department of Astronomy, Cornell University, Ithaca, NY 14850 USA
| | - J. F. Bell
- School of Earth and Space Exploration, Arizona State University, Phoenix, AZ 85287 USA
| | - J. N. Maki
- Jet Propulsion Laboratory, Pasadena, CA 91109 USA
| | - M. Caplinger
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - M. Ravine
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - K. M. Kinch
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - K. Herkenhoff
- USGS Astrogeology Science Center, 2255 N. Gemini Drive, Flagstaff, AZ 86001 USA
| | - B. Horgan
- Earth, Atmospheric, and Planetary Sciences Department, Purdue University, West Lafayette, IN 47907 USA
| | - J. Johnson
- Johns Hopkins Applied Physics Laboratory, Laurel, MD 20723 USA
| | - M. Lemmon
- Space Science Institute, 4765 Walnut St., Suite B, Boulder, CO 80301 USA
| | - G. Paar
- Joanneum Research Forschungsgesellschaft mbH, Steyrergasse 17, 8010 Graz, Austria
| | - M. S. Rice
- Geology Department, Western Washington University, Bellingham, WA 98225 USA
| | - E. Jensen
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - T. M. Kubacki
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - E. Cloutis
- Geography Department, University of Winnepeg, 515 Portage Ave, Winnipeg, MB R3B 2E9 Canada
| | - R. Deen
- Jet Propulsion Laboratory, Pasadena, CA 91109 USA
| | - B. L. Ehlmann
- Jet Propulsion Laboratory, Pasadena, CA 91109 USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91101 USA
| | - E. Lakdawalla
- The Planetary Society, 60 S Los Robles, Pasadena, CA 91101 USA
| | - R. Sullivan
- Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14850 USA
| | - A. Winhold
- School of Earth and Space Exploration, Arizona State University, Phoenix, AZ 85287 USA
| | - A. Parkinson
- Centre for Terrestrial and Planetary Exploration, University of Winnipeg, 515 Portage Ave, Winnipeg, MB R3B 2E9 Canada
| | - Z. Bailey
- Jet Propulsion Laboratory, Pasadena, CA 91109 USA
| | - J. van Beek
- Jet Propulsion Laboratory, Pasadena, CA 91109 USA
| | - P. Caballo-Perucha
- Joanneum Research Forschungsgesellschaft mbH, Steyrergasse 17, 8010 Graz, Austria
| | - E. Cisneros
- School of Earth and Space Exploration, Arizona State University, Phoenix, AZ 85287 USA
| | - D. Dixon
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - C. Donaldson
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - O. B. Jensen
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - J. Kuik
- Centre for Terrestrial and Planetary Exploration, University of Winnipeg, 515 Portage Ave, Winnipeg, MB R3B 2E9 Canada
| | - K. Lapo
- Geology Department, Western Washington University, Bellingham, WA 98225 USA
| | - A. Magee
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - M. Merusi
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - J. Mollerup
- Geology Department, Western Washington University, Bellingham, WA 98225 USA
| | - N. Scudder
- Earth, Atmospheric, and Planetary Sciences Department, Purdue University, West Lafayette, IN 47907 USA
| | - C. Seeger
- Geology Department, Western Washington University, Bellingham, WA 98225 USA
| | - E. Stanish
- Centre for Terrestrial and Planetary Exploration, University of Winnipeg, 515 Portage Ave, Winnipeg, MB R3B 2E9 Canada
| | - M. Starr
- Malin Space Science Systems, San Diego, CA 92121 USA
| | - M. Thompson
- Jet Propulsion Laboratory, Pasadena, CA 91109 USA
| | - N. Turenne
- Centre for Terrestrial and Planetary Exploration, University of Winnipeg, 515 Portage Ave, Winnipeg, MB R3B 2E9 Canada
| | - K. Winchell
- Malin Space Science Systems, San Diego, CA 92121 USA
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DellaGiustina DN, Burke KN, Walsh KJ, Smith PH, Golish DR, Bierhaus EB, Ballouz RL, Becker TL, Campins H, Tatsumi E, Yumoto K, Sugita S, Deshapriya JDP, Cloutis EA, Clark BE, Hendrix AR, Sen A, Al Asad MM, Daly MG, Applin DM, Avdellidou C, Barucci MA, Becker KJ, Bennett CA, Bottke WF, Brodbeck JI, Connolly HC, Delbo M, de Leon J, Drouet d'Aubigny CY, Edmundson KL, Fornasier S, Hamilton VE, Hasselmann PH, Hergenrother CW, Howell ES, Jawin ER, Kaplan HH, Le Corre L, Lim LF, Li JY, Michel P, Molaro JL, Nolan MC, Nolau J, Pajola M, Parkinson A, Popescu M, Porter NA, Rizk B, Rizos JL, Ryan AJ, Rozitis B, Shultz NK, Simon AA, Trang D, Van Auken RB, Wolner CWV, Lauretta DS. Variations in color and reflectance on the surface of asteroid (101955) Bennu. Science 2020; 370:science.abc3660. [PMID: 33033157 DOI: 10.1126/science.abc3660] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 09/24/2020] [Indexed: 11/02/2022]
Abstract
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) of near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their reflectance and texture. Space weathering of Bennu surface materials does not simply progress from red to blue (or vice versa). Instead, freshly exposed, redder surfaces initially brighten in the near-ultraviolet region (i.e., become bluer at shorter wavelengths), then brighten in the visible to near-infrared region, leading to Bennu's moderately blue average color. Craters indicate that the time scale of these color changes is ~105 years. We attribute the reflectance and color variation to a combination of primordial heterogeneity and varying exposure ages.
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Affiliation(s)
- D N DellaGiustina
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. .,Department of Geosciences, University of Arizona, Tucson, AZ, USA
| | - K N Burke
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - K J Walsh
- Southwest Research Institute, Boulder, CO, USA
| | - P H Smith
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D R Golish
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | | | - R-L Ballouz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - T L Becker
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - H Campins
- Department of Physics, University of Central Florida, Orlando, FL, USA
| | - E Tatsumi
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain.,Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - K Yumoto
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - S Sugita
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan
| | - J D Prasanna Deshapriya
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France
| | - E A Cloutis
- Department of Geography, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - B E Clark
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
| | - A R Hendrix
- Planetary Science Institute, Tucson, AZ, USA
| | - A Sen
- Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA
| | - M M Al Asad
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
| | - M G Daly
- The Centre for Research in Earth and Space Science, York University, Toronto, ON, Canada
| | - D M Applin
- Department of Geography, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - C Avdellidou
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - M A Barucci
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France
| | - K J Becker
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C A Bennett
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - W F Bottke
- Southwest Research Institute, Boulder, CO, USA
| | - J I Brodbeck
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - H C Connolly
- Department of Geology, Rowan University, Glassboro, NJ, USA
| | - M Delbo
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - J de Leon
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | | | - K L Edmundson
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - S Fornasier
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France.,Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris CEDEX 05, France
| | | | - P H Hasselmann
- LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique), Observatoire de Paris, Université PSL (Paris Sciences & Lettres), CNRS (Centre National de la Recherche Scientifique), Université de Paris, Sorbonne Université, 92195 Meudon, France
| | - C W Hergenrother
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E S Howell
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - E R Jawin
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - H H Kaplan
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - L Le Corre
- Planetary Science Institute, Tucson, AZ, USA
| | - L F Lim
- Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - J Y Li
- Planetary Science Institute, Tucson, AZ, USA
| | - P Michel
- Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France
| | - J L Molaro
- Planetary Science Institute, Tucson, AZ, USA
| | - M C Nolan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J Nolau
- Lockheed Martin Space, Littleton, CO, USA
| | - M Pajola
- Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Padova, Padua, Italy
| | - A Parkinson
- Department of Geography, University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - M Popescu
- Astronomical Institute of the Romanian Academy, Bucharest, Romania.,Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | - N A Porter
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rizk
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - J L Rizos
- Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain
| | - A J Ryan
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - B Rozitis
- The School of Physical Sciences, The Open University, Milton Keynes, UK
| | - N K Shultz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - A A Simon
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - D Trang
- University of Hawai'i at Mānoa, Hawai'i Institute of Geophysics and Planetology, Honolulu, HI, USA
| | - R B Van Auken
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - C W V Wolner
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
| | - D S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA
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8
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Bourgeois AC, Zulz T, Bruce MG, Stenz F, Koch A, Parkinson A, Hennessy T, Cooper M, Newberry C, Randell E, Proulx JF, Hanley BE, Soini H, Arnesen TM, Mariandyshev A, Jonsson J, Søborg B, Wolfe J, Balancev G, Bruun de Neergaard R, Archibald CP. Tuberculosis in the Circumpolar Region, 2006-2012. Int J Tuberc Lung Dis 2019; 22:641-648. [PMID: 29862948 DOI: 10.5588/ijtld.17.0525] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SETTING The northern circumpolar jurisdictions Canada (Northwest Territories, Nunavik, Nunavut, Yukon), Finland, Greenland, Norway, Russian Federation (Arkhangelsk), Sweden and the United States (Alaska). OBJECTIVE To describe and compare demographic, clinical and laboratory characteristics, including drug resistance and treatment completion, of tuberculosis (TB) cases in the northern circumpolar populations. DESIGN Descriptive analysis of all active TB cases reported from 2006 to 2012 for incidence rate (IR), age and sex distribution, sputum smear and diagnostic site characteristics, drug resistance and treatment completion rates. RESULTS The annual IR of TB disease ranged from a low of 4.3 per 100 000 population in Northern Sweden to a high of 199.5/100 000 in Nunavik, QC, Canada. For all jurisdictions, IR was higher for males than for females. Yukon had the highest proportion of new cases compared with retreatment cases (96.6%). Alaska reported the highest percentage of laboratory-confirmed cases (87.4%). Smear-positive pulmonary cases ranged from 25.8% to 65.2%. Multidrug-resistant cases ranged from 0% (Northern Canada) to 46.3% (Arkhangelsk). Treatment outcome data, available up to 2011, demonstrated >80% treatment completion for four of the 10 jurisdictions. CONCLUSION TB remains a serious public health issue in the circumpolar regions. Surveillance data contribute toward a better understanding and improved control of TB in the north.
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Affiliation(s)
- A-C Bourgeois
- Centre for Communicable Diseases and Infection Control, Public Health Agency of Canada, Ottawa, Ontario, Canada
| | - T Zulz
- Arctic Investigations Program, Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, US Centers for Disease Control and Prevention, Anchorage, Alaska, USA
| | - M G Bruce
- Arctic Investigations Program, Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, US Centers for Disease Control and Prevention, Anchorage, Alaska, USA
| | - F Stenz
- National Board of Health, Nuuk, Greenland
| | - A Koch
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark, Ilisimatusarfik, University of Greenland, Nuuk, Greenland
| | - A Parkinson
- Arctic Investigations Program, Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, US Centers for Disease Control and Prevention, Anchorage, Alaska, USA
| | - T Hennessy
- Arctic Investigations Program, Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Diseases, US Centers for Disease Control and Prevention, Anchorage, Alaska, USA
| | - M Cooper
- Department of Health and Social Services, Division of Public Health, State of Alaska, Anchorage, Alaska, USA
| | - C Newberry
- Population Health Division, Government of Northwest Territories, Yellowknife, Northwest Territories
| | - E Randell
- Department of Health, Government of Nunavut, Iqaluit, Nunavut
| | - J-F Proulx
- Infectious Diseases, Public Health Department, Nunavik Regional Board of Health and Social Services, Kuujjuaq, Quebec
| | - B E Hanley
- Health and Social Services, Government of Yukon, Whitehorse, Yukon Territory, Canada
| | - H Soini
- Infectious Disease Control and Vaccinations Unit, Department of Health Security, National Institute for Health and Welfare, Helsinki, Finland
| | - T M Arnesen
- Department of Tuberculosis, Blood Borne and Sexually Transmitted Infections, Norwegian Institute of Public Health, Oslo, Norway
| | - A Mariandyshev
- Department of Tuberculosis, Northern State Medical University, Arkhangelsk, Russian Federation
| | - J Jonsson
- Swedish Institute for Infectious Disease Control, Department of Preparedness, Stockholm, Sweden
| | - B Søborg
- Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| | - J Wolfe
- National Reference Centre for Mycobacteriology, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - G Balancev
- Department of Tuberculosis, Northern State Medical University, Arkhangelsk, Russian Federation
| | | | - C P Archibald
- Centre for Communicable Diseases and Infection Control, Public Health Agency of Canada, Ottawa, Ontario, Canada
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9
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El-Sharkawi D, Sharma S, Cook L, Hanley B, Johnston R, Arasaretnam A, Lazana I, Greaves P, Parkinson A, Peng Y, Kassam S, Peacock V, Kaczmarski R, Bower M, Cheung B, De Lord C, Cross M, Vroobel K, Wotherspoon A, Aldridge F, Khwaja J, Sharma B, Cwynarski K, Pettengell R, Chau I, Cunningham D, Naresh K, Iyengar S. COMPARISON OF OUTCOMES BETWEEN PATIENTS WITH MYC
REARRANGED DLBCL AND DOUBLE/ TRIPLE HIT HIGH-GRADE B CELL LYMPHOMA: A PAN-LONDON RETROSPECTIVE REVIEW. Hematol Oncol 2019. [DOI: 10.1002/hon.11_2631] [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: 11/08/2022]
Affiliation(s)
- D. El-Sharkawi
- Haematology; Royal Marsden Hospital; Sutton United Kingdom
| | - S. Sharma
- Haematology; Royal Marsden Hospital; Sutton United Kingdom
| | - L. Cook
- Haematology; Hammersmith Hospital; London United Kingdom
| | - B. Hanley
- Haematology; Hammersmith Hospital; London United Kingdom
| | - R. Johnston
- Haematology; Royal Sussex County Hospital; Brighton United Kingdom
| | - A. Arasaretnam
- Haematology; Royal Sussex County Hospital; Brighton United Kingdom
| | - I. Lazana
- Haematology; King's College Hospital; London United Kingdom
| | - P. Greaves
- Haematology; Queen's Hospital; Romford United Kingdom
| | - A. Parkinson
- Haematology; Queen's Hospital; Romford United Kingdom
| | - Y. Peng
- Haematology; St George's University Hospitals NHS Foundation Trust; London United Kingdom
| | - S. Kassam
- Haematology; King's College Hospital; London United Kingdom
| | - V. Peacock
- Haematology; King's College Hospital; London United Kingdom
| | - R. Kaczmarski
- Haematology; Hillingdon Hospital; Uxbridge United Kingdom
| | - M. Bower
- Haematology; Chelsea and Westminster Hospital; London United Kingdom
| | - B. Cheung
- Haematology; Croydon University Hospital; Croydon United Kingdom
| | - C. De Lord
- Haematology; St Helier Hospital; Carshalton United Kingdom
| | - M. Cross
- Haematology; Royal Marsden Hospital; Sutton United Kingdom
| | - K. Vroobel
- Histopathology; Royal Marsden Hospital; Sutton United Kingdom
| | - A. Wotherspoon
- Histopathology; Royal Marsden Hospital; Sutton United Kingdom
| | - F. Aldridge
- Clinical Cytogenetics; Royal Marsden Hospital; Sutton United Kingdom
| | - J. Khwaja
- Haematology; University College Hospital; London United Kingdom
| | - B. Sharma
- Radiology; Royal Marsden Hospital; Sutton United Kingdom
| | - K. Cwynarski
- Haematology; University College Hospital; London United Kingdom
| | - R. Pettengell
- Haematology; St George's University Hospitals NHS Foundation Trust; London United Kingdom
| | - I. Chau
- Department of Medicine; Royal Marsden Hospital; Sutton United Kingdom
| | - D. Cunningham
- Department of Medicine; Royal Marsden Hospital; Sutton United Kingdom
| | - K. Naresh
- Histopathology; Hammersmith Hospital; Hammersmith United Kingdom
| | - S. Iyengar
- Haematology; Royal Marsden Hospital; Sutton United Kingdom
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10
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Burke J, Shatkar V, Parkinson A, Asher S, Almoudaris A, Huang J. TEMS experience from a tertiary referral centre. Int J Surg 2016. [DOI: 10.1016/j.ijsu.2016.08.177] [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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11
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Parkinson A. The Way Forward: Policy Implications for Arctic Collaborations on Water and Sanitation. Int J Epidemiol 2015. [DOI: 10.1093/ije/dyv097.144] [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: 11/13/2022] Open
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12
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Parkinson A. International Circumpolar Surveillance: A brief history. Int J Epidemiol 2015. [DOI: 10.1093/ije/dyv097.076] [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: 11/13/2022] Open
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13
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Gossec L, de Wit M, Heiberg T, Maccarone M, Balanescu A, Balint P, Niedermayer D, Cañete JD, Sánchez Lombarte A, Helliwell P, Parkinson A, Kalyoncu U, Kilic L, Braun J, Kiltz U, Otsa K, Veale D, O’Sullivan D, de Vlam K, Scrivo R, Stamm T, Smolen J, Carton L, Bertheussen H, Kvien TK. OP0111 Elaboration and Preliminary Validation of the Psoriatic Arthritis Impact of Disease (PsAID) Questionnaire. A 13-Country Eular Initiative with Involvement of Patient Research Partners from Each Country. Ann Rheum Dis 2013. [DOI: 10.1136/annrheumdis-2013-eular.316] [Citation(s) in RCA: 2] [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: 11/04/2022]
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14
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Abstract
This unit describes a process for isolation of intact, viable hepatocytes for use in integrated drug metabolism studies. Isolated hepatocytes are increasingly being used as a biological system for studying the in vitro metabolism of xenobiotics. The isolation of hepatocytes from laboratory animals and nontransplantable human livers donated for research activities involves a two-step enzymatic digestion of the liver tissue. Two methods for the perfusion of liver tissue are included: in situ perfusion and isolation of hepatocytes and perfusion of excised tissue. The basic protocol also includes suggestions for designing drug metabolism experiments using hepatocytes. The final protocol describes cryopreservation and long-term storage of isolated hepatocytes.
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Affiliation(s)
- D R Mudra
- XenoTech, LLC, Kansas City, Kansas, USA
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15
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Allgulander C, Betancourt OA, Blackbeard D, Clark H, Colin F, Cooper S, Emsley R, Eriksson L, Gureje O, Halaris A, Hawkridge S, Howell E, Janse van Rensburg B, Jeenah Y, Jordaan G, Joubert AF, Kaliski S, Kinyada E, Kirimi NK, Kleintjes S, Kramer L, Lippi G, Lund C, Mkize D, Munk-Jorgensen P, Nagdee M, Ndetei DM, Parkinson A, Parry C, Patel V, Petersen I, Pienaar W, Pretorius J, Ramlall S, Roos L, Salduker S, Spitzer M, Szabo C, Van Heyningen T, Van Hoof JJM, Van Staden CW. 16th National Congress of the South African Society of Psychiatrists (SASOP). S Afr J Psychiatr 2010. [DOI: 10.4102/sajpsychiatry.v16i3.273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
<p><strong>List of abstracts and authors:</strong></p><p><strong>1. Antipsychotics in anxiety disorders</strong></p><p>Christer Allgulander</p><p><strong>2. Anxiety in somatic disorders</strong></p><p>Christer Allgulander</p><p><strong>3. Community rehabilitation of the schizophrenic patient</strong></p><p>Orlando Alonso Betancourt, Maricela Morales Herrera</p><p><strong>4. Dual diagnosis: A theory-driven multidisciplinary approach for integrative care</strong></p><p>David Blackbeard</p><p><strong>5. The emotional language of the gut - when 'psyche' meets 'soma'</strong></p><p>Helen Clark</p><p><strong>6. The Psychotherapy of bipolar disorder</strong></p><p>Franco Colin</p><p><strong>7. The Psychotherapy of bipolar disorder</strong></p><p>Franco Colin</p><p><strong>8. Developing and adopting mental health policies and plans in Africa: Lessons from South Africa, Uganda and Zambia</strong></p><p>Sara Cooper, Sharon Kleintjes, Cynthia Isaacs, Fred Kigozi, Sheila Ndyanabangi, Augustus Kapungwe, John Mayeya, Michelle Funk, Natalie Drew, Crick Lund</p><p><strong>9. The importance of relapse prevention in schizophrenia</strong></p><p>Robin Emsley</p><p><strong>10. Mental Health care act: Fact or fiction?</strong></p><p>Helmut Erlacher, M Nagdee</p><p><strong>11. Does a dedicated 72-hour observation facility in a district hospital reduce the need for involuntary admissions to a psychiatric hospital?</strong></p><p>Lennart Eriksson</p><p><strong>12. The incidence and risk factors for dementia in the Ibadan study of ageing</strong></p><p>Oye Gureje, Lola Kola, Adesola Ogunniyi, Taiwo Abiona</p><p><strong>13. Is depression a disease of inflammation?</strong></p><p><strong></strong>Angelos Halaris</p><p><strong>14. Paediatric bipolar disorder: More heat than light?</strong></p><p>Sue Hawkridge</p><p><strong>15. EBM: Anova Conundrum</strong></p><p>Elizabeth L (Hoepie) Howell</p><p><strong>16. Tracking the legal status of a cohort of inpatients on discharge from a 72-hour assessment unit</strong></p><p>Bernard Janse van Rensburg</p><p><strong>17. Dual diagnosis units in psychiatric facilities: Opportunities and challenges</strong></p><p>Yasmien Jeenah</p><p><strong>18. Alcohol-induced psychotic disorder: A comparative study on the clinical characteristics of patients with alcohol dependence and schizophrenia</strong></p><p>Gerhard Jordaan, D G Nel, R Hewlett, R Emsley</p><p><strong>19. Anxiety disorders: the first evidence for a role in preventive psychiatry</strong></p><p>Andre F Joubert</p><p><strong>20. The end of risk assessment and the beginning of start</strong></p><p>Sean Kaliski</p><p><strong>21. Psychiatric disorders abd psychosocial correlates of high HIV risk sexual behaviour in war-effected Eatern Uganda</strong></p><p>E Kinyada, H A Weiss, M Mungherera, P Onyango Mangen, E Ngabirano, R Kajungu, J Kagugube, W Muhwezi, J Muron, V Patel</p><p><strong>22. One year of Forensic Psychiatric assessment in the Northern Cape: A comparison with an established assessment service in the Eastern Cape</strong></p><p>N K Kirimi, C Visser</p><p><strong>23. Mental Health service user priorities for service delivery in South Africa</strong></p><p>Sharon Kleintjes, Crick Lund, Leslie Swartz, Alan Flisher and MHaPP Research Programme Consortium</p><p><strong>24. The nature and extent of over-the-counter and prescription drug abuse in cape town</strong></p><p>Liezl Kramer</p><p><strong>25. Physical health issues in long-term psychiatric inpatients: An audit of nursing statistics and clinical files at Weskoppies Hospital</strong></p><p>Christa Kruger</p><p><strong>26. Suicide risk in Schizophrenia - 20 Years later, a cohort study</strong></p><p>Gian Lippi, Ean Smit, Joyce Jordaan, Louw Roos</p><p><strong>27.Developing mental health information systems in South Africa: Lessons from pilot projects in Northern Cape and KwaZulu-Natal</strong></p><p>Crick Lund, S Skeen, N Mapena, C Isaacs, T Mirozev and the Mental Health and Poverty Research Programme Consortium Institution</p><p><strong>28. Mental health aspects of South African emigration</strong></p><p>Maria Marchetti-Mercer</p><p><strong>29. What services SADAG can offer your patients</strong></p><p>Elizabeth Matare</p><p><strong>30. Culture and language in psychiatry</strong></p><p>Dan Mkize</p><p><strong>31. Latest psychotic episode</strong></p><p>Povl Munk-Jorgensen</p><p><strong>32. The Forensic profile of female offenders</strong></p><p>Mo Nagdee, Helmut Fletcher</p><p><strong>33. The intra-personal emotional impact of practising psychiatry</strong></p><p>Margaret Nair</p><p><strong>34. Highly sensitive persons (HSPs) and implications for treatment</strong></p><p>Margaret Nair</p><p><strong>35. Task shifting in mental health - The Kenyan experience</strong></p><p>David M Ndetei</p><p><strong>36. Bridging the gap between traditional healers and mental health in todya's modern psychiatry</strong></p><p>David M Ndetei</p><p><strong>37. Integrating to achieve modern psychiatry</strong></p><p>David M Ndetei</p><p><strong>38. Non-medical prescribing: Outcomes from a pharmacist-led post-traumatic stress disorder clinic</strong></p><p>A Parkinson</p><p><strong>39. Is there a causal relationship between alcohol and HIV? Implications for policy, practice and future research</strong></p><p>Charles Parry</p><p><strong>40. Global mental health - A new global health discipline comes of age</strong></p><p>Vikram Patel</p><p><strong>41. Integrating mental health into primary health care: Lessons from pilot District demonstration sites in Uganda and South Africa</strong></p><p>Inge Petersen, Arvin Bhana, K Baillie and MhaPP Research Programme Consortium</p><p><strong>42. Personality disorders -The orphan child in axis I - Axis II Dichotomy</strong></p><p><strong></strong>Willie Pienaar</p><p><strong>43. Case Studies in Psychiatric Ethics</strong></p><p>Willie Pienaar</p><p><strong>44. Coronary artery disease and depression: Insights into pathogenesis and clinical implications</strong></p><p>Janus Pretorius</p><p><strong>45. Impact of the Mental Health Care Act No. 17 of 2002 on designated hospitals in KwaZulu-Natal: Triumphs and trials</strong></p><p>Suvira Ramlall, Jennifer Chipps</p><p><strong>46. Biological basis of addication</strong></p><p>Solomon Rataemane</p><p><strong>47. Genetics of Schizophrenia</strong></p><p>Louw Roos</p><p><strong>48. Management of delirium - Recent advances</strong></p><p>Shaquir Salduker</p><p><strong>49. Social neuroscience: Brain research on social issues</strong></p><p>Manfred Spitzer</p><p><strong>50. Experiments on the unconscious</strong></p><p>Manfred Spitzer</p><p><strong>51. The Psychology and neuroscience of music</strong></p><p>Manfred Spitzer</p><p><strong>52. Mental disorders in DSM-V</strong></p><p>Dan Stein</p><p><strong>53. Personality, trauma exposure, PTSD and depression in a cohort of SA Metro policemen: A longitudinal study</strong></p><p>Ugashvaree Subramaney</p><p><strong>54. Eating disorders: An African perspective</strong></p><p>Christopher Szabo</p><p><strong>55. An evaluation of the WHO African Regional strategy for mental health 2001-2010</strong></p><p>Thandi van Heyningen, M Majavu, C Lund</p><p><strong>56. A unitary model for the motor origin of bipolar mood disorders and schizophrenia</strong></p><p>Jacques J M van Hoof</p><p><strong>57. The origin of mentalisation and the treatment of personality disorders</strong></p><p>Jacques J M Hoof</p><p><strong>58. How to account practically for 'The Cause' in psychiatric diagnostic classification</strong></p><p>C W (Werdie) van Staden</p><p><strong>POSTER PRESENTATIONS</strong></p><p><strong>59. Problem drinking and physical and sexual abuse at WSU Faculty of Health Sciences, Mthatha, 2009</strong></p><p>Orlando Alonso Betancourt, Maricela Morales Herrera, E, N Kwizera, J L Bernal Munoz</p><p><strong>60. Prevalence of alcohol drinking problems and other substances at WSU Faculty of Health Sciences, Mthatha, 2009</strong></p><p>Orlando Alonso Betancourt, Maricela Morales Herrera, E, N Kwizera, J L Bernal Munoz</p><p><strong>61. Lessons learnt from a modified assertive community-based treatment programme in a developing country</strong></p><p>Ulla Botha, Liezl Koen, John Joska, Linda Hering, Piet Ooosthuizen</p><p><strong>62. Perceptions of psychologists regarding the use of religion and spirituality in therapy</strong></p><p>Ottilia Brown, Diane Elkonin</p><p><strong>63. Resilience in families where a member is living with schizophreni</strong></p><p>Ottilia Brown, Jason Haddad, Greg Howcroft</p><p><strong>64. Fusion and grandiosity - The mastersonian approach to the narcissistic disorder of the self</strong></p><p>William Griffiths, D Macklin, Loray Daws</p><p><strong>65. Not being allowed to exist - The mastersonian approach to the Schizoid disorder of the self</strong></p><p>William Griffiths, D Macklin, Loray Daws</p><p><strong>66. Risky drug-injecting behaviours in Cape Town and the need for a needle exchange programme</strong></p><p>Volker Hitzeroth</p><p><strong>67. Neuroleptic malignant syndrome in adolescents in the Western Cape: A case series</strong></p><p>Terri Henderson</p><p><strong>68. Experience and view of local academic psychiatrists on the role of spirituality in South African specialist psychiatry, compared with a qualitative analysis of the medical literature</strong></p><p>Bernard Janse van Rensburg</p><p><strong>69. The role of defined spirituality in local specialist psychiatric practice and training: A model and operational guidelines for South African clinical care scenarios</strong></p><p>Bernard Janse van Rensburg</p><p><strong>70. Handedness in schizophrenia and schizoaffective disorder in an Afrikaner founder population</strong></p><p>Marinda Joubert, J L Roos, J Jordaan</p><p><strong>71. A role for structural equation modelling in subtyping schizophrenia in an African population</strong></p><p>Liezl Koen, Dana Niehaus, Esme Jordaan, Robin Emsley</p><p><strong>72. Caregivers of disabled elderly persons in Nigeria</strong></p><p>Lola Kola, Oye Gureje, Adesola Ogunniyi, Dapo Olley</p><p><strong>73. HIV Seropositivity in recently admitted and long-term psychiatric inpatients: Prevalence and diagnostic profile</strong></p><p>Christina Kruger, M P Henning, L Fletcher</p><p><strong>74. Syphilis seropisitivity in recently admitted longterm psychiatry inpatients: Prevalence and diagnostic profile</strong></p><p>Christina Kruger, M P Henning, L Fletcher</p><p><strong>75. 'The Great Suppression'</strong></p><p>Sarah Lamont, Joel Shapiro, Thandi Groves, Lindsey Bowes</p><p><strong>76. Not being allowed to grow up - The Mastersonian approach to the borderline personality</strong></p><p>Daleen Macklin, W Griffiths</p><p><strong>77. Exploring the internal confirguration of the cycloid personality: A Rorschach comprehensive system study</strong></p><p>Daleen Macklin, Loray Daws, M Aronstam</p><p><strong>78. A survey to determine the level of HIV related knowledge among adult psychiatric patients admitted to Weskoppies Hospital</strong></p><p><strong></strong> T G Magagula, M M Mamabolo, C Kruger, L Fletcher</p><p><strong>79. A survey of risk behaviour for contracting HIV among adult psychiatric patients admitted to Weskoppies Hospital</strong></p><p>M M Mamabolo, T G Magagula, C Kruger, L Fletcher</p><p><strong>80. A retrospective review of state sector outpatients (Tara Hospital) prescribed Olanzapine: Adherence to metabolic and cardiovascular screening and monitoring guidelines</strong></p><p>Carina Marsay, C P Szabo</p><p><strong>81. Reported rapes at a hospital rape centre: Demographic and clinical profiles</strong></p><p>Lindi Martin, Kees Lammers, Donavan Andrews, Soraya Seedat</p><p><strong>82. Exit examination in Final-Year medical students: Measurement validity of oral examinations in psychiatry</strong></p><p>Mpogisheng Mashile, D J H Niehaus, L Koen, E Jordaan</p><p><strong>83. Trends of suicide in the Transkei region of South Africa</strong></p><p>Banwari Meel</p><p><strong>84. Functional neuro-imaging in survivors of torture</strong></p><p>Thriya Ramasar, U Subramaney, M D T H W Vangu, N S Perumal</p><p><strong>85. Newly diagnosed HIV+ in South Africa: Do men and women enroll in care?</strong></p><p>Dinesh Singh, S Hoffman, E A Kelvin, K Blanchard, N Lince, J E Mantell, G Ramjee, T M Exner</p><p><strong>86. Diagnostic utitlity of the International HIC Dementia scale for Asymptomatic HIV-Associated neurocognitive impairment and HIV-Associated neurocognitive disorder in South Africa</strong></p><p>Dinesh Singh, K Goodkin, D J Hardy, E Lopez, G Morales</p><p><strong>87. The Psychological sequelae of first trimester termination of pregnancy (TOP): The impact of resilience</strong></p><p>Ugashvaree Subramaney</p><p><strong>88. Drugs and other therapies under investigation for PTSD: An international database</strong></p><p>Sharain Suliman, Soraya Seedat</p><p><strong>89. Frequency and correlates of HIV Testing in patients with severe mental illness</strong></p><p>Hendrik Temmingh, Leanne Parasram, John Joska, Tania Timmermans, Pete Milligan, Helen van der Plas, Henk Temmingh</p><p><strong>90. A proposed mental health service and personnel organogram for the Elizabeth Donkin psychiatric Hospital</strong></p><p>Stephan van Wyk, Zukiswa Zingela</p><p><strong>91. A brief report on the current state of mental health care services in the Eastern Cape</strong></p><p>Stephan van Wyk, Zukiswa Zingela, Kiran Sukeri, Heloise Uys, Mo Nagdee, Maricela Morales, Helmut Erlacher, Orlando Alonso</p><p><strong>92. An integrated mental health care service model for the Nelson Mandela Bay Metro</strong></p><p>Stephan van Wyk, Zukiswa Zingela, Kiran Sukeri</p><p><strong>93. Traditional and alternative healers: Prevalence of use in psychiatric patients</strong></p><p>Zukiswa Zingela, S van Wyk, W Esterhuysen, E Carr, L Gaauche</p>
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Umehara KI, Susaki Y, Van Teylingen RHJ, Neat JN, Ndikum-Moffor F, Noguchi K, Usui T, Parkinson A, Kamimura H. Evaluation of the inhibitory and induction potential of YM758, a novel If channel inhibitor, for human P450-mediated metabolism. Eur J Drug Metab Pharmacokinet 2009; 33:211-23. [PMID: 19230594 DOI: 10.1007/bf03190875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study was designed to examine the in vitro metabolism of YM758, a novel cardiovascular agent, and to evaluate its potential to cause drug interactions and induction of CYP isozymes. After incubation with pooled human liver microsomes, YM758 was converted to two major metabolites (AS2036313-00, and YM-394111 or YM-394112). The formation of AS2036313-00, and YM-394111 or YM-394112 were mediated by CYP2D6 and CYP3A4, respectively, which was elucidated by using a bank of human liver microsomes and recombinant CYP enzymes in combination with the utilization of typical substrates and inhibitors. The Ki values of YM758 for midazolam, nifedipine, and metoprolol metabolism ranged from 59 to 340 microM, being much higher than the YM758 concentration in human plasma. The formation of AS2036313-00, and YM-394111 or YM-394112 was inhibited by quinidine and ketoconazole with Ki values of 140 and 0.24 microM, respectively, which indicates that YM758 metabolism may be affected by coadministration of strong CYP2D6 and 3A4 inhibitors in vivo, given the clinical plasma concentrations of quinidine and ketoconazole. After human hepatocytes were exposed to 10 microM YM758, microsomal activity and mRNA level for CYP1A2 were not induced while those for CYP3A4 were slightly induced. The tested concentration was much higher than that in human plasma, which suggests that the induction potential of YM758 is also negligible.
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Affiliation(s)
- K I Umehara
- Drug Metabolism Research Laboratories, Drug Discovery Research, Astellas Pharma Inc., Tokyo, Japan
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Yamaori S, Yamazaki H, Iwano S, Kiyotani K, Matsumura K, Saito T, Parkinson A, Nakagawa K, Kamataki T. Ethnic differences between Japanese and Caucasians in the expression levels of mRNAs for CYP3A4, CYP3A5 and CYP3A7: lack of co-regulation of the expression of CYP3A in Japanese livers. Xenobiotica 2008; 35:69-83. [PMID: 15788369 DOI: 10.1080/00498250400021796] [Citation(s) in RCA: 39] [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: 10/25/2022]
Abstract
Using a newly developed real-time reverse transcriptase-polymerase chain reaction method, mRNAs were quantitated for CYP3A4, CYP3A5 and CYP3A7 in adult livers from 24 Japanese and 24 Caucasian subjects to elucidate the potential ethnic differences in the expression levels of human cytochrome P450 (CYP) 3As. The expression level of CYP3A4 mRNA in Japanese livers (n = 24) was approximately three times higher than that in Caucasian livers (n = 24, p < 0.001). The mean level of CYP3A5 mRNA was approximately twice higher in Japanese (n = 9) than in Caucasians (n = 5) heterozygous for the CYP3A5 *1 allele (p = 0.057). The CYP3A7 mRNA level was twice higher in Japanese (n = 24) than in Caucasians (n = 22) carrying the CYP3A7 *1A/ *1A genotype (p = 0.042). The level of CYP3A4 mRNA did not correlate with those of CYP3A5 (r = 0.044, n = 24) or CYP3A7 (r = 0.21, n = 24) mRNAs in Japanese livers in contrast to co-regulatory expression of CYP3A4, CYP3A5 and CYP3A7 in Caucasian livers. The results indicate that there are ethnic differences in the expression levels of adult liver CYP3A mRNAs between Japanese and Caucasians, and that the mechanism(s) regulating the hepatic CYP3A expression may be different between these ethnic groups.
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Affiliation(s)
- S Yamaori
- Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
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Bruce M, Deeks S, Cottle T, Palacios C, Case C, Hemsley C, Lovgren M, Sobol I, Corriveau A, Larke B, Hennessy T, Debyle C, Harker-Jones M, Hurlburt D, Peters H, Parkinson A. O253 Epidemiology of Haemophilus in fluenzae serotype A from 2000–2005, an emerging pathogen in Northern Canada and Alaska. Int J Antimicrob Agents 2007. [DOI: 10.1016/s0924-8579(07)70161-9] [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]
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Tyler RS, Parkinson A, Wilson B, Parkinson W, Lowder M, Witt S, Rubinstein J, Gantz B. Evaluation of different choices of n in an n of m processor for cochlear implants. Adv Otorhinolaryngol 2002; 57:311-5. [PMID: 11892176 DOI: 10.1159/000059135] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
- R S Tyler
- Departments of Speech Pathology and Otolaryngology, Head and Neck Surgery, University of Iowa, Iowa City, Iowa, USA.
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Abstract
AIM To evaluate out-patient angiography performed by nurses and radiographers. MATERIALS AND METHODS A protocol for out-patient angiography performed by nurses and radiographers was drawn up and approved by the Trust's Risk Management Committee. Following training, two experienced radiographers and one nurse undertook elective peripheral or renal angiography according to the protocol on 187 patients. Angiograms were performed using a 3F catheter introduced into the abdominal aorta from a femoral approach. Patients were discharged after 2 hours and contacted by telephone the following morning. RESULTS No patient refused consent for the procedure. One hundred and seventy-two patients underwent successful catheterization without assistance from a radiologist. Radiologist assistance was required with femoral puncture or catheter/guidewire manipulation in 15 cases (8%). Images were considered diagnostic by the reporting radiologist in all but one case. This patient was recalled for further aortogram and pressure measurements. There was a single puncture site complication due to transient stenosis of the common femoral artery at the puncture site. This is thought to have been the result of subintimal injection of local anaesthetic, and it resolved spontaneously over 30 minutes. There were no delayed complications. CONCLUSION Experienced nurses and radiographers can rapidly acquire the skills to perform diagnostic angiography safely and efficiently.
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Affiliation(s)
- N Chalmers
- Department of Radiology, Manchester Royal Infirmary, Manchester, UK.
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Abstract
Photooxidation (UV radiation) and enhanced photooxidation (UVC/H2O2) are water treatment technologies which remove aquatic natural organic matter (NOM) by photodegradation, producing lower molecular weight components and CO2. Since these technologies are being investigated for the treatment of drinking water, knowledge of the potential toxicity of the photooxidation by-products is vital. The potential toxicity of UVA-, UVB-, UVC-irradiated, and UVC/H2O2-treated aquatic NOM in two spot samples from two Australian reservoirs was analysed in two spot samples using Vibriofischeri in the Microtox test, African green monkey kidney cells (AS/NZS 4020:1999), and Daphnia carinata in an acute immobilisation test. Toxicity was not apparent for both the Microtox procedure and cytotoxicity analyses for the UVC-irradiated and UVC/H2O2-treated NOM samples, while UVA- and UVB-irradiated water samples were non-toxic to D. carinata. In contrast, acute toxicity was observed for UVC- and UVC/H2O2-treated water samples. The observed toxicity was attributed to photooxidative degradation of NOM-metal binding sites, which resulted in the release of bioavailable copper ions, as evidenced by higher concentrations of free copper ions in photooxidised water. As the total copper concentrations of the two raw water samples were well below the Australian Water Quality Guidelines for metals in domestic supplies, the release of copper from photooxidised NOM is unlikely to cause health concerns in these samples.
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Affiliation(s)
- A Parkinson
- Department of Chemical and Metallurgical Engineering, RMIT University, Melbourne, Australia
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Abstract
The purpose of this study was to develop and validate a method of estimating the relative "weight" that a multichannel cochlear implant user places on individual channels, indicating its contribution to overall speech recognition. The correlational method as applied to speech recognition was used both with normal-hearing listeners and with cochlear implant users fitted with six-channel speech processors. Speech was divided into frequency bands corresponding to the bands of the processor and a randomly chosen level of corresponding filtered noise was added to each channel on each trial. Channels in which the signal-to-noise ratio was more highly correlated with performance have higher weights, and conversely, channels in which the correlations were smaller have lower weights. Normal-hearing listeners showed approximately equal weights across frequency bands. In contrast, cochlear implant users showed unequal weighting across bands, and varied from individual to individual with some channels apparently not contributing significantly to speech recognition. To validate these channel weights, individual channels were removed and speech recognition in quiet was tested. A strong correlation was found between the relative weight of the channel removed and the decrease in speech recognition, thus providing support for use of the correlational method for cochlear implant users.
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Affiliation(s)
- M A Mehr
- Department of Speech Pathology and Audiology, University of Iowa, Iowa City 52242, USA
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Antonian L, Zhang H, Yang C, Wagner G, Shawver LK, Shet M, Ogilvie B, Madan A, Parkinson A. Biotransformation of the anti-angiogenic compound SU5416. Drug Metab Dispos 2000; 28:1505-12. [PMID: 11095590] [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: 02/18/2023] Open
Abstract
SU5416 [3-(3,5-dimethyl-1H-pyrrol-2-ylmethylene)-1, 3-dihydro-indol-2-one], an inhibitor of VEGF (vascular endothelial growth factor) receptor tyrosine kinase, Flk-1/KDR (fetal liver kinase 1/kinase insert domain-containing receptor), also known as VEGF receptor 2 (VEGFR2) is in advanced clinical trials for treatment of AIDS-related Kaposi's sarcoma and colorectal and nonsmall cell lung cancers. Since this chemical class has not been studied previously with therapeutic intent, the present study was designed to investigate the in vitro metabolism of SU5416 by mouse, rat, dog, monkey, and human liver microsomes and to identify the major metabolites of SU5416. An HPLC procedure was developed and validated to resolve and quantify SU5416 and its metabolites. To evaluate the in vitro metabolism of SU5416, pooled liver microsomes from mice, rats, dogs, monkeys, and humans were incubated with SU5416 (25 microM) in the presence of an NADPH-generating system. In the presence of NADPH, mouse, rat, dog, monkey, and human liver microsomes converted SU5416 to at least 12, 9, 9, 7, and 6 polar metabolites, respectively. Microsomal metabolism of SU5416 showed marked species differences in the levels of different metabolites formed. The overall rate of SU5416 metabolism by liver microsomes from the species examined followed the rank order: monkey > or = mouse approximately rat > dog > human. Two major metabolites of SU5416 were identified, a hydroxymethyl derivative of SU5416 (M12) and a carboxylic acid derivative of SU5416 (M6), by spectroscopic methods and comparison with authentic compounds. Both of these oxidative metabolites were further metabolized in vivo through glucuronidation. The metabolic fate of SU5416 in microsomes from various species as well as data from in vivo biotransformation in the rat are discussed.
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Affiliation(s)
- L Antonian
- SUGEN, Inc., South San Francisco, California 94080, USA.
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Parkinson A, Petersen K, Mc Mahon B, Beck-Sagué CM. Laboratory diagnosis of infections related to chronic disease in minority communities. Hepatitis B and hepatocellular carcinoma in Alaska natives. Am Clin Lab 2000; 19:14. [PMID: 11146985] [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] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- A Parkinson
- Artic Investigations Program, National Center for Infectious Diseases, Center for Disease Control and Prevention, 4055 Tudor Centre Dr., Anchorage, AK 99508, USA.
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Singleton R, Bulkow LR, Levine OS, Butler JC, Hennessy TW, Parkinson A. Experience with the prevention of invasive Haemophilus influenzae type b disease by vaccination in Alaska: the impact of persistent oropharyngeal carriage. J Pediatr 2000; 137:313-20. [PMID: 10969253 DOI: 10.1067/mpd.2000.107843] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES To report the epidemiology of invasive Haemophilus influenzae type b (Hib) disease in high-risk Alaska Native infants before and after universal infant Hib vaccination and evaluate an increase in invasive Hib disease in 1996 after changing Hib vaccine type. STUDY DESIGN Statewide laboratory surveillance for invasive Hib disease has been conducted since 1980. Three cross-sectional Hib carriage studies were conducted in 1997 and 1998. RESULTS The invasive Hib disease rate in Alaska Natives decreased from 332 cases per 100,000 children <5 years old in 1980-1991 to 17:100,000 in 1992-1995 but increased primarily in rural areas to 57.9:100,000 after a switch in Hib vaccine types. Carriage studies in 5 rural Alaska Native villages showed oropharyngeal Hib carriage as high as 9.3% in children aged 1 to 5 years; in contrast, carriage in urban Alaska Native children was <1%. CONCLUSIONS Although Hib disease has decreased in Alaska, the rate of Hib disease and carriage in rural Alaska Natives did not decrease to the same extent as in non-Natives and urban Alaska Natives. Use of polyribosylribitol phosphate-outer-membrane protein conjugate vaccine for the first vaccine dose is critical to disease control in this population with continued transmission in infants <6 months of age. The ability to eliminate Hib carriage and disease may be affected by population characteristics, vaccination coverage, and Hib vaccine type used. This may pose a challenge to global elimination of Hib.
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Affiliation(s)
- R Singleton
- Arctic Investigations Program, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska 99508, USA
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Sidhu JS, Marcus CB, Parkinson A, Omiecinski CJ. Differential induction of cytochrome P450 gene expression by 4n-alkyl-methylenedioxybenzenes in primary rat hepatocyte cultures. J Biochem Mol Toxicol 2000; 12:253-62. [PMID: 9664231 DOI: 10.1002/(sici)1099-0461(1998)12:5<253::aid-jbt1>3.0.co;2-k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 11/09/2022]
Abstract
A well-characterized primary rat hepatocyte culture system was used to examine induction patterns of cytochrome 450 gene expression by a series of 4-n-alkyl-methylenedioxybenzene (MDBs) derivatives. Hepatocytes were treated for 24, 48, or 72 hours with 0-500 microM of the MDB compounds, and total cellular RNA and protein from each treatment was evaluated by hybridization and immunochemical techniques. Exposure to MDB congeners possessing increasing 4-n-alkyl side-chain length (C0-C8) resulted in dose- and structure-dependent activation of CYP2B1, 2B2, 3A1, 1A1, and 1A2 gene expression. At equivalent 100 microM concentrations, the C6 and C8 MDB congeners were more effective than the prototypical inducer phenobarbital (PB) with respect to induction potency of CYP2B1, CYP2B2, and CYP3A1 gene expression. In contrast to PB, longer side-chain-substituted MDBs effectively induced CYP1A1 and CYP1A2 gene expression, in addition to the CYP2B and CYP3A genes. At equivalent molar concentrations, the catechol derivative of C6-MDB was ineffective in its ability to induce CYP gene expression, indicating the importance of the intact methylenedioxy bridge in the induction mechanism. Levels of MDB-inducible CYP2B1 and CYP2B2 mRNA were highly correlated with CYP2B1/2 apoprotein levels, ascertained by immunoblot analysis of cultured hepatocyte S9 fractions. Compared with results from previous in vivo analysis (12), the current data indicate that pharmacodynamic factors may influence MDB induction profiles and that differences in MDB effects on CYP gene expression result depending on distinct structure-activity relationships.
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Affiliation(s)
- J S Sidhu
- Department of Environmental Health, University of Washington, Seattle 98105-6099, USA
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Liu J, Sendelbach LE, Parkinson A, Klaassen CD. Endotoxin pretreatment protects against the hepatotoxicity of acetaminophen and carbon tetrachloride: role of cytochrome P450 suppression. Toxicology 2000; 147:167-76. [PMID: 10924799 DOI: 10.1016/s0300-483x(00)00193-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [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: 11/21/2022]
Abstract
Bacterial endotoxin (lipopolysaccharide, LPS) is known to potentiate the toxicity of many hepatotoxicants. However, exposure to a sublethal dose of LPS renders animals tolerant to a lethal dose of LPS, and protects against the toxicity of some chemicals. This study was designed to examine the effects of LPS pretreatment on acetaminophen- and carbon tetrachloride (CCl(4))-induced liver injury in LPS-sensitive C3H/OuJ and LPS-resistant C3H/HeJ mice. Pretreatment of male C3H/OuJ mice with a single injection of LPS (0. 1 mg/kg, ip, for 24 h) protected against the hepatotoxic effects of acetaminophen (400 mg/kg) and carbon tetrachloride (CCl(4), 30 mg/kg), as indicated by serum alanine aminotransferase activity. In contrast, pretreatment of C3H/HeJ mice with 0.1 or 10 mg/kg LPS afforded no protection against the hepatotoxic effects of acetaminophen and CCl(4). In an attempt to determine the mechanism of LPS-induced protection against acetaminophen- and CCl(4)-induced hepatotoxicity in C3H/OuJ mice, liver cytochrome P450 was determined 24 h after LPS injection. LPS treatment caused a 26% decrease in total P450 content in C3H/OuJ but not in C3H/HeJ mice. CYP3A-catalized testosterone 6 beta-, 2 beta-, and 15 beta-hydroxylation was decreased 40% by LPS only in C3H/OuJ mice. To determine whether the differences to LPS-response in the two stains of mice is mediated by a strain-related difference in the release of cytokines, mice were pretreated with interleukin-1 (IL-1 alpha, 5 x 10(5) U/mouse), and the hepatoprotection and hepatic P450 enzymes were examined. IL-1 alpha pretreatment equally protected against the hepatotoxicity of acetaminophen and CCl(4) in both strains, and suppressed the total microsomal P450 and P450 enzyme-catalyzed testosterone hydroxylation to a similar extent. In conclusion, LPS pretreatment suppressed hepatic cytochrome P450 enzymes and protected against the hepatotoxicity of acetaminophen and CCl(4) in LPS-sensitive C3H/OuJ mice, but not in LPS-refractory C3H/HeJ mice. This protective effect of LPS appears to be mediated through the release of cytokines such as IL-1 alpha, which in turn suppresses the cytochrome P450 responsible for the activation of acetaminophen and CCl(4) to reactive metabolites.
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Affiliation(s)
- J Liu
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160-7417, USA
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Abstract
The aim of this study was to test suitable culture conditions for maintaining normal cellular cytoarchitecture and inducibility of P450 enzymes in primary cultures of human hepatocytes by prototypical inducers. The selectivity and sensitivity of a sandwich culture system were determined by treating cultures with a number of clinically relevant drugs that are known to be inducers of either rodent and/or human P450 enzymes. The results showed that considerable induction of CYP3A4 activity is observed at DMSO concentrations greater than 0.1% (v/v). No differences in P450 induction response were observed between cultures maintained under different matrix conditions. However, the matrix condition considered to be optimal for maintaining cellular integrity, protein yields, and P450 enzyme induction was a sandwich configuration in combination with modified Chee's medium containing insulin (6.25 microg/mL) and dexamethasone (< or =0.1 microM). Under these conditions, induction of CYP3A4 occurred at clinically relevant drug concentrations, and maximal activities were achieved after 3 days of exposure. Overall, the response of human hepatocyte cultures to treatment with both positive and negative modulators was found to reflect that observed in vivo with respect to both enzyme specificity and potency of enzyme induction, although considerable sample-to-sample variability was observed in the magnitude of induction.
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Affiliation(s)
- E LeCluyse
- University of North Carolina at Chapel Hill, School of Pharmacy, 27599, USA.
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31
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Robertson P, DeCory HH, Madan A, Parkinson A. In vitro inhibition and induction of human hepatic cytochrome P450 enzymes by modafinil. Drug Metab Dispos 2000; 28:664-71. [PMID: 10820139] [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: 02/16/2023] Open
Abstract
The ability of modafinil to affect human hepatic cytochrome P450 (CYP) activities was examined in vitro. The potential for inhibition of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4/5, and CYP4A9/11 by modafinil (5-250 microM) was evaluated with pooled human liver microsomes. Modafinil exhibited minimal capacity to inhibit any CYP enzyme, except CYP2C19. Modafinil inhibited the 4'-hydroxylation of S-mephenytoin, a marker substrate for CYP2C19, reversibly and competitively with a K(i) value of 39 microM, which approximates the steady-state C(max) value of modafinil in human plasma at a dosage of 400 mg/day. No irreversible inhibition of any CYP enzyme was observed, and there was no evidence of metabolism-dependent inhibition. The potential for induction of CYP activity was evaluated by exposing primary cultures of human hepatocytes to modafinil (10-300 microM). Microsomes were then prepared and assayed for CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4/5 activities. The mean activities of microsomal CYP1A2, CYP2B6, and CYP3A4/5 from modafinil-treated hepatocytes were higher (up to 2-fold) than those in the solvent-treated controls but were less than those produced by reference inducers of these enzymes. At high concentrations of modafinil (>/=100 microM), the mean activity of CYP2C9 was decreased (up to 60%) relative to that in the solvent controls. Overall, modafinil was shown to have effects on human hepatic CYP1A2, CYP2B6, CYP2C9, CYP2C19, and CYP3A4/5 activities in vitro. Although effects obtained in vitro are not always predictive of effects in vivo, such results provide a rational basis for understanding drug-drug interactions that are observed clinically and for planning subsequent investigations.
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Affiliation(s)
- P Robertson
- Department of Drug Safety and Disposition, Cephalon, Inc., West Chester, Pennsylvania, USA.
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32
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Rodger A, Sanders KJ, Hannon MJ, Meistermann I, Parkinson A, Vidler DS, Haworth IS. DNA structure control by polycationic species: polyamine, cobalt ammines, and di-metallo transition metal chelates. Chirality 2000; 12:221-36. [PMID: 10790193 DOI: 10.1002/(sici)1520-636x(2000)12:4<221::aid-chir9>3.0.co;2-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [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: 11/10/2022]
Abstract
Many polycationic species bind to DNA and induce structural changes. The work reported here is the first phase of a program whose long-term aim is to create a class of simple and inexpensive sequence-selective compounds that will enable enhanced DNA structure control for a wide range of applications. Three classes of molecule have been included in this work: the polyamine spermine (charge: 4(+)) and spermidine (charge: 3(+)) (which are known to induce a wide range of DNA conformational changes but whose binding modes are still not well understood); cobalt (III) amine transition metal complexes as potential polyamine mimics and [Fe(H(2)O)(6)](3+); and the first member of a new class of di-metallo tris-chelated cylinders of helical structure (charge 4(+)). Temperature-dependent absorption, circular dichroism, linear dichroism, gel electrophoresis, and molecular modeling data are presented. The cobalt amines prove to be effective polyamine mimics, although their binding appears to be restricted to backbone and major groove. All the ligands stabilize the DNA, but the 4(+) di-iron tris-chelate does so comparatively weakly and seems to have a preference for single-stranded DNA. All the molecules studied bend the DNA, with the di-iron tris-chelate having a particularly dramatic effect even at very low drug load.
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Affiliation(s)
- A Rodger
- Department of Chemistry, University of Warwick, Coventry, UK.
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33
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LeCluyse EL, Ahlgren-Beckendorf JA, Carroll K, Parkinson A, Johnson J. Regulation of glutathione S-transferase enzymes in primary cultures of rat hepatocytes maintained under various matrix configurations. Toxicol In Vitro 2000; 14:101-15. [PMID: 10793289 DOI: 10.1016/s0887-2333(00)00007-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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: 10/16/2022]
Abstract
Primary rat hepatocytes were cultured under various matrix and media conditions and examined after 1 week for the expression and regulation of cytosolic glutathione S-transferase (GST) enzymes. Striking effects on cell morphology were observed in relation to the different matrix conditions, whereas media effects were less prominent. Hepatocytes cultured in serum-free Dulbecco's modified Eagle's medium (DMEM) or modified Chee's medium (MCM) maintained similar levels of total GST protein regardless of the matrix configuration or corresponding cell integrity. However, HPLC analysis showed a differential expression pattern of individual GST subunits in both a time- and medium-dependent fashion. A variable, but pronounced, matrix and medium effect was observed on the induction of total GST expression by various prototypical inducers. Dexamethasone (10 microM) induced subunits A2, M1 and M2 in a medium- and matrix-dependent fashion, whereas phenobarbital (100 microM) induced significantly only subunit A2. beta-Naphthoflavone (50 microM) suppressed all GST subunit expression except subunit P1, which was induced in a matrix- and medium-dependent fashion. These studies show that total basal level expression of GSTs in vitro is reflective of a concomitant increase in mu and pi class subunits and a decrease in alpha class subunits. Moreover, the matrix and medium conditions influence both the basal and inducible expression of GST subunits in cultured rat hepatocytes.
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Affiliation(s)
- E L LeCluyse
- Department of Pharmacology, Toxicology, and Therapeutics, Center for Environmental and Occupational Health, Kansas University Medical Center, Kansas City, Kansas, USA
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34
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Lehman-McKeeman LD, Caudill D, Vassallo JD, Pearce RE, Madan A, Parkinson A. Effects of musk xylene and musk ketone on rat hepatic cytochrome P450 enzymes. Toxicol Lett 1999; 111:105-15. [PMID: 10630706 DOI: 10.1016/s0378-4274(99)00172-1] [Citation(s) in RCA: 17] [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: 11/23/2022]
Abstract
The purpose of the present work was to characterize the effect of musk xylene (MX) and musk ketone (MK) treatment on rat hepatic cytochrome P450 enzymes. Male F344 rats were dosed orally with MX (10, 50 or 200 mg/kg) or MK (20, 100 or 200 mg/kg) for 7 days, after which CYP1A, 2B and 3A enzyme activities and protein levels were determined. MX treatment resulted in a two- to four-fold increase in the activity of CYP1A, 2B and 3A enzymes. For CYP1A and 3A, these changes were consistent with small increases in immunoreactive proteins. However, for CYP2B, despite only a three-fold increase in enzyme activity, protein levels were increased nearly 50-fold relative to control. This induction occurred by transcriptional activation of the CYP2B1 gene as evidenced by increased steady state CYP2B1 mRNA levels. In contrast to MX, MK treatment increased CYP2B activity, protein and mRNA levels. However MK treatment also increased CYP1A enzyme activity nearly 30-fold higher than control rats, a profile that was markedly different from MX, and very different from its effects in mice (Stuard, S.B., Caudill, D., Lehman-Mc-Keeman, L.D., 1997. Characterization of the effects of musk ketone on mouse cytochrome P450 enzymes. Fund. Appl. Toxicol. 40, 264-271). These results indicate that in rats, MX is an inducer of CYP2B enzymes, but these enzymes are not functionally active. In contrast, MK also induces CYP2B enzymes, with no concurrent inactivation. MK also exhibits a unique pattern of cytochrome P450 induction by increasing both CYP1A and CYP2B in rats.
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Affiliation(s)
- L D Lehman-McKeeman
- Human Safety Department, Procter and Gamble Co., Miami Valley Laboratories, Cincinnati, OH 45253-8707, USA.
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35
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LeCluyse E, Bullock P, Madan A, Carroll K, Parkinson A. Influence of extracellular matrix overlay and medium formulation on the induction of cytochrome P-450 2B enzymes in primary cultures of rat hepatocytes. Drug Metab Dispos 1999; 27:909-15. [PMID: 10421618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
The effect of medium formulation, composition of extracellular matrix overlay, and culture dish material on liver microsomal cytochrome P-450 (CYP) 2B induction by phenobarbital (PB) was investigated in primary cultures of rat hepatocytes. When hepatocytes were maintained on Permanox dishes with an overlay of either collagen (type I) or Matrigel, Williams' E medium was superior to other medium formulations in terms of the magnitude of induction of CYP2B on a per milligram microsomal protein basis. Modified Chee's medium (MCM) and hepatocyte culture medium were intermediate in their capacity to sustain induction of CYP2B by PB, and Dulbecco's modified Eagle's medium was slightly less effective. The overall induction of CYP2B activity by PB was, on average, 50% lower in hepatocytes cultured on polystyrene dishes (LUX). Little or no difference was observed between hepatocytes overlaid with collagen and those overlaid with Matrigel. MCM was superior to Williams' E medium in terms of the yield of microsomal protein and the ultrastructural features of the hepatocyte monolayers. CYP2B induction by PB was optimal after 3 days of treatment in either medium. CYP1A, CYP3A, and CYP4A activities could be induced in vitro by prototypical inducing agents in hepatocytes cultured on Permanox dishes with MCM and a Matrigel overlay to comparable levels observed in vivo. The results of these studies show that medium formulation and culture vessel material, but not the type of extracellular matrix overlay, have significant effects on the induction of CYP enzymes in cultured rat hepatocytes maintained in a sandwich configuration.
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Affiliation(s)
- E LeCluyse
- Department of Pharmacology, Toxicology and Therapeutics, Center for Environmental and Occupational Health, University of Kansas Medical Center, Kansas City, Kansas, USA
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36
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Karron RA, Singleton RJ, Bulkow L, Parkinson A, Kruse D, DeSmet I, Indorf C, Petersen KM, Leombruno D, Hurlburt D, Santosham M, Harrison LH. Severe respiratory syncytial virus disease in Alaska native children. RSV Alaska Study Group. J Infect Dis 1999; 180:41-9. [PMID: 10353859 DOI: 10.1086/314841] [Citation(s) in RCA: 107] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Hospitalization rates for respiratory syncytial virus (RSV) infection range from 1 to 20/1000 infants. To determine the rate and severity of RSV infections requiring hospitalization for infants in the Yukon-Kuskokwim (YK) Delta of Alaska, a 3-year prospective surveillance study was conducted. The annual rate of RSV hospitalization for YK Delta infants <1 year of age was 53-249/1000. RSV infection was the most frequent cause of infant hospitalization. RSV disease severity did not differ among non-high-risk infants in the YK Delta and at Johns Hopkins Hospital (JHH). On average, 1/125 infants born in the YK Delta required mechanical ventilation for RSV infection. During the peak season, approximately $1034/child <3 years of age was spent on RSV hospitalization in the YK Delta. In YK Delta infants </=6 months old, RSV microneutralizing antibody titers <1200 were associated with severe disease (odds ratio=6.2, P=.03). In the YK Delta and at JHH, newborns may be at greater risk for severe RSV illness than previously thought.
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Affiliation(s)
- R A Karron
- Center for Immunization Research, Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD 21205, USA.
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37
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McKim JM, Choudhuri S, Wilga PC, Madan A, Burns-Naas LA, Gallavan RH, Mast RW, Naas DJ, Parkinson A, Meeks RG. Induction of hepatic xenobiotic metabolizing enzymes in female Fischer-344 rats following repeated inhalation exposure to decamethylcyclopentasiloxane (D5). Toxicol Sci 1999; 50:10-9. [PMID: 10445748 DOI: 10.1093/toxsci/50.1.10] [Citation(s) in RCA: 21] [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: 11/14/2022] Open
Abstract
Decamethylcyclopentasiloxane (D5) is a cyclic siloxane with a wide range of commercial applications. The present study was designed to investigate the effects of D5 on the expression and activity of selected rat hepatic phase I and phase II metabolizing enzymes. Female Fischer-344 rats were exposed to 160 ppm D5 vapors (6 h/day, 7 days/week, for 28 days) by whole-body inhalation. Changes in the activity and relative abundance of hepatic microsomal cytochromes P450 (CYP1A, CYP2B, CYP3A, and CYP4A), epoxide hydrolase, and UDP-glucuronosyltransferase (UDPGT) were measured. Repeated inhalation exposure of rats to D5 increased liver size by 16% relative to controls by day 28. During a 14-day post-exposure period, liver size in D5-exposed animals showed significant recovery. Exposure to D5 did not change total hepatic P450, but increased the activity of hepatic NADPH-cytochrome c reductase by 1.4-fold. An evaluation of cytochrome P450 (CYP) enzymes in hepatic microsomes prepared from D5-exposed rats revealed a slight (1.8-fold) increase in 7-ethoxyresorufin O-deethylase (EROD) activity, but no change in immunoreactive CYP1A1/2 protein. A moderate increase (4.2-fold) in both 7-pentoxyresorufin O-depentylase (PROD) activity and immunoreactive CYP2B1/2 protein (3.3-fold) was observed. Testosterone 6beta-hydroxylase activity was also increased (2.4-fold) as was CYP3A1/2 immunoreactive protein. Although a small increase in 11- and 12-hydroxylation of lauric acid was detected, no change in immunoreactive CYP4A levels was measured. Liver microsomal epoxide hydrolase activity and immunoreactive protein increased 1.7- and 1.4-fold, respectively, in the D5-exposed group. UDPGT activity toward chloramphenicol was induced 1.8-fold, while no change in UDPGT activity toward 4-nitrophenol was seen. These results suggest that the profile for enzyme induction following inhalation exposure of female Fischer-344 rats to D5 vapors is similar to that reported for phenobarbital, and therefore D5 may be described as a weak "phenobarbital-like" inducer.
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Affiliation(s)
- J M McKim
- Dow Corning Corporation, Health and Environmental Sciences, Midland, Michigan 48686, USA.
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38
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Granvil CP, Madan A, Sharkawi M, Parkinson A, Wainer IW. Role of CYP2B6 and CYP3A4 in the in vitro N-dechloroethylation of (R)- and (S)-ifosfamide in human liver microsomes. Drug Metab Dispos 1999; 27:533-41. [PMID: 10101149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
The central nervous system toxicity of ifosfamide (IFF), a chiral antineoplastic agent, is thought to be dependent on its N-dechloroethylation by hepatic cytochrome P-450 (CYP) enzymes. The purpose of this study was to identify the human CYPs responsible for IFF-N-dechloroethylation and their corresponding regio- and enantioselectivities. IFF exists in two enantiomeric forms, (R) - and (S)-IFF, which can be dechloroethylated at either the N2 or N3 positions, producing the corresponding (R,S)-2-dechloroethyl-IFF [(R, S)-2-DCE-IFF] and (R,S)-3-dechloroethyl-IFF [(R,S)-3-DCE-IFF]. The results of the present study suggest that the production of (R)-2-DCE-IFF and (S)-3-DCE-IFF from (R)-IFF is catalyzed by different CYPs as is the production of (S)-2-DCE-IFF and (R)-3-DCE-IFF from (S)-IFF. In vitro studies with a bank of human liver microsomes revealed that the sample-to-sample variation in the production of (S)-3-DCE-IFF from (R)-IFF and (S)-2-DCE-IFF from (S)-IFF was highly correlated with the levels of (S)-mephenytoin N-demethylation (CYP2B6), whereas (R)-2-DCE-IFF production from (R)-IFF and (R)-3-DCE-IFF production from (S)-IFF were both correlated with the activity of testosterone 6beta-hydroxylation (CYP3A4/5). Experiments with cDNA-expressed P-450 and antibody and chemical inhibition studies supported the conclusion that the formation of (S)-3-DCE-IFF and (S)-2-DCE-IFF is catalyzed primarily by CYP2B6, whereas (R)-2-DCE-IFF and (R)-3-DCE-IFF are primarily the result of CYP3A4/5 activity.
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Affiliation(s)
- C P Granvil
- Département de Pharmacologie, Université de Montréal, Montréal, Québec, Canada
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39
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Madan A, DeHaan R, Mudra D, Carroll K, LeCluyse E, Parkinson A. Effect of cryopreservation on cytochrome P-450 enzyme induction in cultured rat hepatocytes. Drug Metab Dispos 1999; 27:327-35. [PMID: 10064562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
In the present study, we evaluated the inducibility of cytochrome P-450 (CYP) CYP1A, CYP2B, CYP3A, and CYP4A by beta-naphthoflavone, phenobarbital, dexamethasone, and clofibric acid, respectively, in primary hepatocyte cultures prepared from both fresh and cryopreserved rat hepatocytes. Rat hepatocytes were successfully thawed and cultured after cryopreservation in liquid nitrogen for up to 1 month. Percentage of total recovery, viable cell recovery, and final viability of the cells were 68%, 72%, and 85%, respectively. Regardless of whether they were cryopreserved or not, cultured hepatocytes exhibited near-normal morphology. Treatment of cryopreserved hepatocytes with beta-naphthoflavone caused an 8-fold increase in 7-ethoxyresorufin O-dealkylase (CYP1A1/2) activity, with an EC50 of 1.5 microM; treatment with phenobarbital caused a 26-fold increase in 7-pentoxyresorufin O-dealkylase (CYP2B1/2) activity, with an EC50 of 10 microM; treatment with dexamethasone caused a 10-fold increase in testosterone 6beta-hydroxylase (CYP3A1/2) activity, with an EC50 of 1.3 microM, whereas treatment with clofibric acid caused a 3-fold increase in lauric acid 12-hydroxylase (CYP4A1-3) activity, with an EC50 of 170 microM. The induction of CYP1A, CYP2B, CYP3A, and CYP4A enzymes by these inducers was confirmed by Western immunoblotting. The patterns of P-450 induction in cryopreserved rat hepatocytes, in terms of concentration response, reproducibility, magnitude, and specificity of response, were similar to those observed in freshly isolated hepatocytes. Additionally, the magnitude and specificity of induction was similar to that observed in vivo in rats. In conclusion, under the conditions examined, cryopreserved rat hepatocytes appear to be a suitable in vitro system for evaluating xenobiotics as inducers of P-450 enzymes.
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Affiliation(s)
- A Madan
- XenoTech, Limited Liability Company, Kansas City, Kansas 66103, USA.
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40
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Galil K, Singleton R, Levine OS, Fitzgerald MA, Bulkow L, Getty M, Perkins BA, Parkinson A. Reemergence of invasive Haemophilus influenzae type b disease in a well-vaccinated population in remote Alaska. J Infect Dis 1999; 179:101-6. [PMID: 9841828 DOI: 10.1086/314569] [Citation(s) in RCA: 107] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Before vaccination, Alaska Natives experienced very high rates of invasive Haemophilus influenzae type b (Hib) disease and carriage. Vaccination with Hib conjugate vaccine PRP-OMP (polyribosylribitol phosphate Neisseria meningitidis outer membrane protein) began in 1991 and resulted in a sharp decline in cases. In 1996, after switching to a different Hib conjugate vaccine, DTP-HbOC (which combines diphtheria-tetanus-whole cell pertussis vaccines with HbOC [Hib oligosaccharide CRM197]), cases of invasive Hib disease increased, suggesting ongoing Hib transmission despite widespread vaccination. To determine the prevalence of and risk factors for carriage, a cross-sectional study of oropharyngeal Hib carriage was conducted among Alaska Native children aged 1-5 years in remote southwestern Alaska. Of 496 children with swabs taken, 46 (9.3%) were colonized with Hib. Carriage rates varied by village from 2.2% to 13.2% and by age from 6.1% in 1-year-olds to 14.7% in 5-year-olds. Crowding was associated with Hib carriage. Widespread vaccination with PRP-OMP Hib conjugate vaccine did not eliminate carriage in this population of Alaska Natives, and ongoing carriage contributed to disease resurgence.
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Affiliation(s)
- K Galil
- National Immunization Program, CDC Mailstop E61, 1600 Clifton Road, Atlanta, GA 30333, USA
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41
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Parkinson A, Fikar CR. Location and indexing of articles written by podiatric physicians. J Am Podiatr Med Assoc 1998; 88:514-6. [PMID: 9791958 DOI: 10.7547/87507315-88-10-514] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study was undertaken to determine which biomedical journals contain articles written by podiatric physicians and in which indexing sources such articles are likely to appear. A survey was conducted of the 20 most frequently published podiatrist authors from a selected group of podiatric journals during the period from 1990 to 1995. Articles published by these authors during the study period were examined to determine where they had appeared. The MEDLINE database was found to contain the largest number of citations to articles written by these podiatric physicians. Both the Podiatry Index and Embase are also very good sources of citations to podiatric medical literature and should be used to supplement MEDLINE searches.
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Affiliation(s)
- A Parkinson
- New York College of Podiatric Medicine, New York, USA
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Dwyer-Nield LD, Thompson JA, Peljak G, Squier MK, Barker TD, Parkinson A, Cohen JJ, Dinsdale D, Malkinson AM. Selective induction of apoptosis in mouse and human lung epithelial cell lines by the tert-butyl hydroxylated metabolite of butylated hydroxytoluene: a proposed role in tumor promotion. Toxicology 1998; 130:115-27. [PMID: 9865479 DOI: 10.1016/s0300-483x(98)00102-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Butylated hydroxytoluene (BHT) causes lung injury in mice and promotes tumor formation. Hydroxylation of a tert-butyl group on BHT to yield the metabolite, 6-tert-butyl-2-[2'-(2'-hydroxymethyl)-propyl]-4-methylphenol (BHTOH), may be required. BHTOH is more potent than BHT on an equimolar basis in causing lung damage, enhancing lung tumor development, killing isolated bronchiolar non-ciliated Clara cells, and inhibiting lung epithelial gap junctional intercellular communication. One mechanism proposed for tumor promoting agents is selective cytotoxicity; killing normal cells allows uninhibited clonal expansion of neighboring initiated cells. We compared the abilities of BHT, BHTOH, and other BHT metabolites to kill non-tumorigenic and tumorigenic mouse and human lung cell lines, and examined the contribution of apoptosis to this cytotoxicity. These cells lack the cytochrome P450 2B isozyme necessary for converting BHT to BHTOH. BHTOH and 4-hydroperoxy-4-methyl-2,6-di-tert-butyl-2,5-cyclohex-adienone+ ++ (BHTOOH) were most toxic, BHT and 2,6-di-tert-butyl-1,4-benzoquinone (BHTQu) were less potent, and 4-methyl BHT metabolites that are not pneumotoxic were ineffective. BHTOH most strongly induced apoptosis, based on nuclear condensation and transmission electron microscopy. Non-tumorigenic cells were as susceptible to cell death as the neoplastic cell lines when apoptosis and necrosis are not distinguished, but more sensitive to BHTOH-induced apoptosis. An apoptotic mechanism may underlie the lung tumor promoting actions of BHTOH.
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Affiliation(s)
- L D Dwyer-Nield
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, Denver 80262, USA
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Madan A, Parkinson A, Faiman MD. Identification of the human P-450 enzymes responsible for the sulfoxidation and thiono-oxidation of diethyldithiocarbamate methyl ester: role of P-450 enzymes in disulfiram bioactivation. Alcohol Clin Exp Res 1998; 22:1212-9. [PMID: 9756035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Diethyldithiocarbamate methyl ester (DDTC-Me) is a precursorto the formation of S-methyl-N,N-diethylthiolcarbamate sulfoxide, the active metabolite proposed to be responsible for the alcohol deterrent effects of disulfiram. The present study investigated the role of human cytochrome P-450 (CYP) enzymes in sulfoxidation and thiono-oxidation of DDTC-Me, intermediary steps in the activation of disulfiram. Several approaches were used in an attempt to delineate the particular P-450 enzyme(s) involved in the sulfoxidation and thiono-oxidation of DDTC-Me. These approaches included the use of cDNA-expressed human P-450 enzymes, correlation analysis with sample-to-sample variation in human P-450 enzymes in a bank of human liver microsomes, and chemical and antibody inhibition studies. Multiple human P-450 enzymes (CYP3A4, CYP1A2, CYP2A6, and CYP2D6) catalyzed the sulfoxidation of DDTC-Me, as determined with cDNA-expressed enzymes. Several lines of evidence suggest that the sulfoxidation of DDTC-Me by human liver microsomes is primarily catalyzed by CYP3A4/5, including (1) a high correlation between DDTC-Me sulfoxidation and testosterone 6beta-hydroxylation; (2) increased DDTC-Me sulfoxidation in the presence of alpha-naphthoflavone, an activator of CYP3A enzymes; (3) inhibition of this reaction by inhibitors of CYP3A4/5 enzymes, such as troleandomycin and ketoconazole; and (4) inhibition of DDTC-Me sulfoxidation by antibodies against CYP3A enzymes. On the other hand, several lines of evidence suggested that the thiono-oxidation of DDTC-Me by human liver microsomes is catalyzed in part by CYP1A2, CYP2B6, CYP2E1, and CYP3A4/5, including (1) these human P450 enzymes among others have the capacity to catalyze this reaction, as determined with cDNA-expressed enzymes; (2) a high correlation between DDTC-Me thiono-oxidation and testosterone 6beta-hydroxylation, weak inhibition by ketoconazole, troleandomycin, and anti-CYP3A antibodies suggested a minor role for CYP3A4; (3) a high correlation with immunoreactive CYP2B6 suggested involvement of this enzyme; (4) weak inhibition of DDTC-Me thiono-oxidation by furafylline and anti-CYP1A antibody suggested involvement of CYP1A2; and (5) inhibition of DDTC-Me thiono-oxidation by DDTC and anti-CYP2E antibodies suggested a role for CYP2E1. Collectively, these data suggested CYP3A4/5 enzymes are the major contributors to the sulfoxidation of DDTC-Me by human liver microsomes, and CYP1A2, CYP2B6, CYP2E1, and CYP3A4/5 contribute toward DDTC-Me thiono-oxidation by human liver microsomes. This study, in conjunction with others (Madan et al., Drug Metab. Dispos. 23:1153-1162, 1995), may help explain the variability in disulfiram's effectiveness as an alcohol deterrent.
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Affiliation(s)
- A Madan
- Department of Pharmacology and Toxicology, University of Kansas, Lawrence 66045, USA
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Draper AJ, Madan A, Smith K, Parkinson A. Development of a non-high pressure liquid chromatography assay to determine testosterone hydroxylase (CYP3A) activity in human liver microsomes. Drug Metab Dispos 1998; 26:299-304. [PMID: 9531515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The major pathway of testosterone oxidation by human liver microsomes is the formation of 6beta-hydroxytestosterone, which is catalyzed by CYP3A4/5 and which accounts for 75-80% of all metabolites formed. In the present study, we describe a non-high pressure liquid chromatography assay (HPLC) of CYP3A4/5 activity based on the release of tritium (with formation of tritiated water) upon incubation of [1,2,6,7-3H]testosterone with human liver microsomes and NADPH. Unreacted testosterone and its metabolites were quantitatively extracted from the incubation mixture with activated charcoal under conditions that resulted in no extraction of tritiated water. The amount of tritiated water formed was quantified by liquid scintillation spectrometry and compared with the amount of hydroxylated testosterone metabolites formed, as determined by HPLC. Rates of tritium release from [1,2,6, 7-3H]testosterone paralleled rates of testosterone 6beta-hydroxylation as a function of incubation time, the amount of microsomal protein, and the concentration of substrate (which yielded identical apparent Km and Vmax values). The sample-to-sample variation in tritium release from [1,2,6,7-3H]testosterone with a panel of human liver microsomes was highly correlated with rates of testosterone 6beta-hydroxylation and terfenadine metabolism, two commonly used markers of CYP3A activity. Several recombinant human P450 enzymes were incubated with [1,2,6,7-3H]testosterone, and only cDNA-expressed CYP3A4 catalyzed a high rate of tritium release. The close agreement between the tritium-release assay and HPLC procedure for measuring testosterone oxidation indicates that tritium release from [1,2,6,7-3H]testosterone provides a simple and rapid alternative to the HPLC procedure for measuring CYP3A4/5 activity in human liver microsomes. However, the tritium-release assay may have limited value in measuring CYP3A activity in liver microsomes from other species due to the presence of other P450 enzymes that can catalyze tritium release from [1,2,6,7-3H]testosterone.
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Affiliation(s)
- A J Draper
- Department of Pharmacology, Toxicology and Therapeutics, Center for Environmental and Occupational Health, University of Kansas Medical Center, Kansas City 66160-7417, USA
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Draper AJ, Madan A, Latham J, Parkinson A. Development of a non-high pressure liquid chromatography assay to determine [14C]chlorzoxazone 6-hydroxylase (CYP2E1) activity in human liver microsomes. Drug Metab Dispos 1998; 26:305-12. [PMID: 9531516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The activity of liver microsomal CYP2E1 is commonly measured as the rate of 5-chloro-2-benzoxazolone (chlorzoxazone) 6-hydroxylation, which requires separation of 6-hydroxychlorzoxazone and chlorzoxazone by high pressure liquid chromatography (HPLC). In the present study, we describe a solvent extraction (non-HPLC) assay for measuring CYP2E1 activity, based on the 6-hydroxylation of [14C]chlorzoxazone. When [14C]chlorzoxazone was incubated with human or rat liver microsomes in the presence of NADPH, the major product formed was 6-[14C]hydroxychlorzoxazone. Unreacted [14C]chlorzoxazone was quantitatively extracted from the incubation mixture with dichloromethane under conditions that resulted in approximately 45% extraction of 6-[14C]hydroxychlorzoxazone. The amount of 6-[14C]hydroxychlorzoxazone remaining in the aqueous incubation mixture ( approximately 55% of the total amount formed) was quantified by liquid scintillation spectrometry. The limit of detection for this assay was 100 pmol of 6-[14C]hydroxychlorzoxazone. The solvent extraction procedure was validated by comparing the rates of formation of 6-[14C]hydroxychlorzoxazone with those determined by HPLC under a variety of experimental conditions. The close correspondence between the two analytical methods suggests that the extraction procedure for measuring 6-[14C]hydroxychlorzoxazone provides a simple, sensitive, and rapid alternative to the HPLC procedure for measuring CYP2E1 activity. In rats, the assay is not specific for CYP2E1 because CYP1A1 also catalyzes the 6-hydroxylation of chlorzoxazone. Recombinant human CYP1A1 also catalyzed the 6-hydroxylation of chlorzoxazone (at (1)/(5) the rate of CYP2E1), although CYP1A1 is not expressed in human liver microsomes. The non-HPLC assay was used to investigate the postulated role of CYP1A2 in the 6-hydroxylation of chlorzoxazone by human liver microsomes. Recombinant CYP1A2 did not catalyze the 6-hydroxylation of chlorzoxazone, and studies with 1-[(3,4-dimethoxyphenyl)methyl]-6,7-dimethoxyisoquinoline, which inhibits CYP1A2 but not CYP2E1, indicated that, in human liver microsomes, the 6-hydroxylation of chlorzoxazone is catalyzed by CYP2E1 with little or no contribution from CYP1A2 enzymes over a wide range of substrate concentrations.
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Affiliation(s)
- A J Draper
- Department of Pharmacology, Toxicology and Therapeutics, Center for Environmental and Occupational Health, University of Kansas Medical Center, Kansas City 66160-7417, USA
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McKim JM, Wilga PC, Kolesar GB, Choudhuri S, Madan A, Dochterman LW, Breen JG, Parkinson A, Mast RW, Meeks RG. Evaluation of octamethylcyclotetrasiloxane (D4) as an inducer of rat hepatic microsomal cytochrome P450, UDP-glucuronosyltransferase, and epoxide hydrolase: a 28-day inhalation study. Toxicol Sci 1998; 41:29-41. [PMID: 9520339 DOI: 10.1006/toxs.1997.2398] [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: 11/22/2022] Open
Abstract
Repeated inhalation exposure to octamethylcyclotetrasiloxane (D4) produces a reversible and dose-related hepatomegaly and proliferation of hepatic endoplasmic reticulum in rats. However, the effects of D4 on the expression of cytochrome P450 enzymes have not been evaluated. In the present study, the time course for changes in hepatic microsomal cytochrome P450 enzyme expression following repeated inhalation exposure to D4 vapors was determined in male and female Fischer 344 rats. Animals were exposed to D4 vapor at concentrations of 70 and 700 ppm, via whole body inhalation for 6 h/day, 5 days/week for 4 weeks. Specified animals were euthanized on exposure days 3, 7, 14, 21, and 28. Microsomal fractions were prepared from fresh liver by differential centrifugation. Enzyme activity as well as immunoreactive protein levels of several cytochrome P450 enzymes (CYP), epoxide hydrolase, and UDP-glucuronosyltransferase (UDPGT) were evaluated. The time course for enzyme induction was monitored by measuring 7-ethoxyresorufin O-deethylase (EROD) and 7-pentoxyresorufin O-depentylase (PROD) activities on days 3, 7, 14, 21, and 28. CYP1A1/2 activity, as determined by EROD activity, was increased approximately 2- to 3-fold over the exposure period. However, an examination of immunoreactive protein revealed no induction of CYP1A1 and a suppression of CYP1A2 in the 700 ppm D4 group. In comparison, CYP2B1/2 enzyme activity, as determined by PROD, was significantly increased as early as day 3 in both the 70 and 700 ppm D4 groups of male and female rats. Overall, PROD activity on day 28 was induced more than 10-fold in the 70 ppm D4 groups and more than 20-fold in the 700 ppm D4 groups. The increase in PROD activity was paralleled by a comparable increase in CYP2B1/2 immunoreactive protein. There was a modest (2- to 3-fold) increase in CYP3A1/2 activity and immunoreactive protein, as determined by 6 beta-hydroxylation of testosterone and Western blot analysis. Expression of CYP enzymes was at or near maximum by day 14 and remained relatively constant throughout the exposure period. On day 28, epoxide hydrolase activity and immunoreactive protein were induced (2- to 3-fold) in a dose-dependent manner. Only slight changes in the expression and activity of UDPGT were detected, and these did not appear to be dose related. Thus, repeated inhalation exposure to D4 induces CYP enzymes and epoxide hydrolase in a manner similar to that observed for phenobarbital (PB). Therefore, D4 can be described as a "PB-like" inducer of hepatic microsomal enzymes in the Fischer 344 rat.
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Affiliation(s)
- J M McKim
- Dow Corning Corporation, Health and Environmental Sciences, Midland, Michigan 48686, USA
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Lee RP, Parkinson A, Forkert PG. Isozyme-selective metabolism of ethyl carbamate by cytochrome P450 (CYP2E1) and carboxylesterase (hydrolase A) enzymes in murine liver microsomes. Drug Metab Dispos 1998; 26:60-5. [PMID: 9443854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cytochrome P450 and carboxylesterase enzymes have been implicated in the metabolism of the carcinogen ethyl carbamate (EC). In this study, we have used a murine liver microsomal system to investigate the relative contributions of P450 and carboxylesterase isozymes to hepatic metabolism of EC. N-Nitrosodimethylamine (NDMA) demethylation and p-nitrophenyl acetate (PNA) hydrolysis were used as catalytic markers of CYP2E1 and carboxylesterase enzymes, respectively. Incubation of liver microsomes with EC (1 mM) produced slight but significant decreases in NDMA demethylation and PNA hydrolysis activities. Incubation of microsomes with paraoxon (PAX), a general carboxylesterase inhibitor, or phenylmethylsulfonyl fluoride (PMSF), a specific inhibitor of hydrolase A, produced decreases of 85 and 45%, respectively, in carboxylesterase activities; neither of the inhibitors elicited alterations in levels of NDMA demethylation. Reaction of microsomes with either PAX or PMSF and then with EC exacerbated the reduction (285%) of NDMA demethylation, and this loss corresponded to decreases in immunodetectable CYP2E1 content. The reduction in PNA hydrolysis activity induced by PAX, PMSF, or EC correlated with decreased immunodetectable hydrolase A in liver microsomes; however, reaction with PAX and not PMSF or EC resulted in loss of immunoreactivity for hydrolase B. These data correlated with levels of covalent binding of [ethyl-14C]EC to liver microsomes, which were significantly elevated in incubations conducted with PAX or PMSF. Antibody inhibition of the CYP2E1 enzyme significantly reduced levels of binding to microsomal proteins, compared with control levels. These results are consistent with the premise that EC is metabolized by CYP2E1 and hydrolase A in liver microsomes of mice.
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Affiliation(s)
- R P Lee
- Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada, K7L 3N6
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Tyler RS, Fryauf-Bertschy H, Kelsay DM, Gantz BJ, Woodworth GP, Parkinson A. Speech perception by prelingually deaf children using cochlear implants. Otolaryngol Head Neck Surg 1997; 117:180-7. [PMID: 9334763 DOI: 10.1016/s0194-5998(97)70172-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [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: 02/05/2023]
Abstract
In this investigation we measured the performance of 50 prelingually deaf children on several speech perception tests. Children were from 2 to 15 years of age, and some children were tested with as much as 5 years of cochlear implant use. Speech perception tests included the recognition of stress pattern, consonants, vowels, words, and sentences. The audiovisual perception of consonants was also measured. Average results indicated that gains were being made in the perception of stress and words in a closed-set context within 1 year from implantation. The perception of words in an open-set context demonstrated much slower increases over time. Large individual differences were observed. Some preliminary data suggest that children who receive implants before the age of 4 years obtain higher scores, on average, than children who receive implants after the age of 5 years. Some children become part-time users or nonusers of their cochlear implants. The average results from 18 congenitally deaf children were significantly higher than the average results from 12 children with prelingually acquired deafness after 3 years of implant use. Information on vowel and consonant features shows increases in performance after 2 years of cochlear implant use, with the exception of the place feature. For this feature, no changes were observed. Vision-alone testing indicated that lipreading performance increased over time. An audiovisual enhancement provided by the cochlear implant was observed for all features.
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Affiliation(s)
- R S Tyler
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City 52242, USA
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Abstract
Nine organic solvents and 47 commonly used P450 substrates and inhibitors were examined for their effects on coumarin 7-hydroxylase (CYP2A6) activity in human liver microsomes. Of the nine organic solvents examined (final concentration 1%, v/v), only methanol did not inhibit the 7-hydroxylation of coumarin (0.5 to 50 microM) by human liver microsomes. Dioxane and tetra-hydrofuran, which are structurally related to coumarin, were the most inhibitory solvents examined. Although the rates of coumarin 7-hydroxylation varied enormously among nine samples of human liver microsomes and cDNA-expressed CYP2A6 (Vmax = 179 to 2470 pmol/ mg protein/min), the Km for coumarin 7-hydroxylation was fairly constant (ranging from 0.50 to 0.70 microM). The following chemicals caused little or no inhibition of CYP2A6 as defined by a Ki > 200 microM: caffeine, chlorzoxazone, cimetidine, dextromethorphan, diazepam, diclofenac, erythromycin, ethinylestradiol, ethynyltestosterone, fluconazole, furafylline, furfural, hexobarbital, itraconazole, mephenytoin, methimazole, metronidazole, naringenin, naringin, nifedipine, norfloxacin, norgestrel, orphenadrine, quinidine, papaverine, phenacetin, pyrimethamine, ranitidine, spironolactone, sulfaphenazole, sulfinpyrazone, testosterone, tolbutamide, troleandomycin, and warfarin. In other words, these chemicals, at a final concentration of 100 microM, failed to inhibit CYP2A6 when the concentration of coumarin was equal to Km (0.50 microM). The following chemicals were classified as strong inhibitors of CYP2A6 (defined by Ki < 200 microM): clotrimazole, diethyldithiocarbamate, ellipticine, ketoconazole, 8-methoxypsoralen, 4-methylpyrazole, metyrapone, miconazole, alpha-naphthoflavone, nicotine, p-nitrophenol, and tranylcypromine. The potency with which each chemical inhibited the 7-hydroxylation of coumarin was independent of which sample of human liver microsomes was studied. One of the most potent inhibitors of coumarin 7-hydroxylase was 8-methoxypsoralen (methoxsalen), which was determined to be a mechanism-based inhibitor (suicide substrate) of CYP2A6 (k(inactivation) 0.5 min-1). With the exception of 8-methoxypsoralen, preincubation of human liver microsomes and NADPH with the aforementioned inhibitors did not increase their ability to inhibit CYP2A6. The most potent competitive inhibitor of CYP2A6 was tranylcypromine (Ki = 0.04 microM). Several of the chemicals that strongly inhibited CYP2A6, such as ketoconazole and tranylcypromine, are often used with the intention of selectively inhibiting human P450 enzymes other than CYP2A6. The results of this study underscore the need for a systematic evaluation of the specificity of commonly used P450 inhibitors.
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Affiliation(s)
- A J Draper
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City 66160-7417, USA
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Bookstaff RC, Murphy VA, Skare JA, Minnema D, Sanzgiri U, Parkinson A. Effects of doxylamine succinate on thyroid hormone balance and enzyme induction in mice. Toxicol Appl Pharmacol 1996; 141:584-94. [PMID: 8975784 DOI: 10.1006/taap.1996.0325] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 02/03/2023]
Abstract
The effects of doxylamine (as the succinate salt) on microsomal enzyme activity and serum thyroid hormone levels were examined in B6C3F1 mice following dietary exposure for 7 or 15 days (0, 40, 375, 750, or 1500 ppm in diet, expressed as free base doxylamine). In addition, the hepatic P450 enzyme inducer sodium phenobarbital (375 ppm, expressed as free acid phenobarbital) was used as a positive control for CYP2B induction. Exposure of mice to doxylamine produced dose-related increases in liver weight at both time points. Liver weights were also increased in the phenobarbital-treated mice. Doxylamine treatment caused a dose-dependent increase (up to 2.6-fold) in liver microsomal cytochrome P450 in both male and female mice, at both time points. Analyses of the activities of various hepatic microsomal cytochromes P450 indicated that doxylamine caused a marked induction of CYP2B enzymes. This was demonstrated by a large increase in the O-dealkylation of 7-pentoxyresorufin (up to 38-fold) and the 16beta-hydroxylation of testosterone (up to 6.9-fold), both of which are indicative of CYP2B induction. In addition, like phenobarbital, doxylamine treatment resulted in a modest induction of CYP3A and CYP2A enzymes and approximately a 50% increase in thyroxine-glucuronosyltransferase activity. Doxylamine did not appear to induce P450 enzymes in the CYP1A, CYP2E, or CYP4A enzyme subfamilies. None of the enzyme-inducing effects of doxylamine could be distinguished from those of phenobarbital. These results suggest that doxylamine is a phenobarbital-type inducer of liver microsomal cytochrome P450 in B6C3F1 mice. Exposure to either doxylamine or phenobarbital also resulted in decreases in serum thyroxine (T4) levels (approximately 80% of control) with compensatory increases in serum thyroid-stimulating hormone levels (approximately 4-fold). No clear changes in serum triiodothyronine levels were apparent. These findings are consistent with the hypothesis that doxylamine increases the activity of those hepatic enzymes involved in T4 metabolism.
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Affiliation(s)
- R C Bookstaff
- The Procter & Gamble Company, Cincinnati, Ohio 45040-9462, USA
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