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Goodacre S, Sutton L, Ennis K, Thomas B, Hawksworth O, Iftikhar K, Croft SJ, Fuller G, Waterhouse S, Hind D, Stevenson M, Bradburn MJ, Smyth M, Perkins GD, Millins M, Rosser A, Dickson J, Wilson M. Prehospital early warning scores for adults with suspected sepsis: the PHEWS observational cohort and decision-analytic modelling study. Health Technol Assess 2024; 28:1-93. [PMID: 38551135 PMCID: PMC11017155 DOI: 10.3310/ndty2403] [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] [Indexed: 04/02/2024] Open
Abstract
Background Guidelines for sepsis recommend treating those at highest risk within 1 hour. The emergency care system can only achieve this if sepsis is recognised and prioritised. Ambulance services can use prehospital early warning scores alongside paramedic diagnostic impression to prioritise patients for treatment or early assessment in the emergency department. Objectives To determine the accuracy, impact and cost-effectiveness of using early warning scores alongside paramedic diagnostic impression to identify sepsis requiring urgent treatment. Design Retrospective diagnostic cohort study and decision-analytic modelling of operational consequences and cost-effectiveness. Setting Two ambulance services and four acute hospitals in England. Participants Adults transported to hospital by emergency ambulance, excluding episodes with injury, mental health problems, cardiac arrest, direct transfer to specialist services, or no vital signs recorded. Interventions Twenty-one early warning scores used alongside paramedic diagnostic impression, categorised as sepsis, infection, non-specific presentation, or other specific presentation. Main outcome measures Proportion of cases prioritised at the four hospitals; diagnostic accuracy for the sepsis-3 definition of sepsis and receiving urgent treatment (primary reference standard); daily number of cases with and without sepsis prioritised at a large and a small hospital; the minimum treatment effect associated with prioritisation at which each strategy would be cost-effective, compared to no prioritisation, assuming willingness to pay £20,000 per quality-adjusted life-year gained. Results Data from 95,022 episodes involving 71,204 patients across four hospitals showed that most early warning scores operating at their pre-specified thresholds would prioritise more than 10% of cases when applied to non-specific attendances or all attendances. Data from 12,870 episodes at one hospital identified 348 (2.7%) with the primary reference standard. The National Early Warning Score, version 2 (NEWS2), had the highest area under the receiver operating characteristic curve when applied only to patients with a paramedic diagnostic impression of sepsis or infection (0.756, 95% confidence interval 0.729 to 0.783) or sepsis alone (0.655, 95% confidence interval 0.63 to 0.68). None of the strategies provided high sensitivity (> 0.8) with acceptable positive predictive value (> 0.15). NEWS2 provided combinations of sensitivity and specificity that were similar or superior to all other early warning scores. Applying NEWS2 to paramedic diagnostic impression of sepsis or infection with thresholds of > 4, > 6 and > 8 respectively provided sensitivities and positive predictive values (95% confidence interval) of 0.522 (0.469 to 0.574) and 0.216 (0.189 to 0.245), 0.447 (0.395 to 0.499) and 0.274 (0.239 to 0.313), and 0.314 (0.268 to 0.365) and 0.333 (confidence interval 0.284 to 0.386). The mortality relative risk reduction from prioritisation at which each strategy would be cost-effective exceeded 0.975 for all strategies analysed. Limitations We estimated accuracy using a sample of older patients at one hospital. Reliable evidence was not available to estimate the effectiveness of prioritisation in the decision-analytic modelling. Conclusions No strategy is ideal but using NEWS2, in patients with a paramedic diagnostic impression of infection or sepsis could identify one-third to half of sepsis cases without prioritising unmanageable numbers. No other score provided clearly superior accuracy to NEWS2. Research is needed to develop better definition, diagnosis and treatments for sepsis. Study registration This study is registered as Research Registry (reference: researchregistry5268). Funding This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 17/136/10) and is published in full in Health Technology Assessment; Vol. 28, No. 16. See the NIHR Funding and Awards website for further award information.
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Affiliation(s)
- Steve Goodacre
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
- Emergency Department, Northern General Hospital, Sheffield, UK
| | - Laura Sutton
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Kate Ennis
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Ben Thomas
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Olivia Hawksworth
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | | | - Susan J Croft
- Emergency Department, Northern General Hospital, Sheffield, UK
| | - Gordon Fuller
- Emergency Department, Northern General Hospital, Sheffield, UK
| | - Simon Waterhouse
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Daniel Hind
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Matt Stevenson
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Mike J Bradburn
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - Michael Smyth
- Warwick Clinical Trials Unit, University of Warwick, Coventry, UK
| | - Gavin D Perkins
- Warwick Clinical Trials Unit, University of Warwick, Coventry, UK
| | - Mark Millins
- Yorkshire Ambulance Service NHS Trust, Wakefield, UK
| | - Andy Rosser
- West Midlands Ambulance Service University NHS Foundation Trust, Midlands, UK
| | - Jon Dickson
- Academic Unit of Primary Medical Care, University of Sheffield, Sheffield, UK
| | - Matthew Wilson
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
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Breeze PR, Squires H, Ennis K, Meier P, Hayes K, Lomax N, Shiell A, Kee F, de Vocht F, O’Flaherty M, Gilbert N, Purshouse R, Robinson S, Dodd PJ, Strong M, Paisley S, Smith R, Briggs A, Shahab L, Occhipinti J, Lawson K, Bayley T, Smith R, Boyd J, Kadirkamanathan V, Cookson R, Hernandez‐Alava M, Jackson CH, Karapici A, Sassi F, Scarborough P, Siebert U, Silverman E, Vale L, Walsh C, Brennan A. Guidance on the use of complex systems models for economic evaluations of public health interventions. Health Econ 2023; 32:1603-1625. [PMID: 37081811 PMCID: PMC10947434 DOI: 10.1002/hec.4681] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 05/03/2023]
Abstract
To help health economic modelers respond to demands for greater use of complex systems models in public health. To propose identifiable features of such models and support researchers to plan public health modeling projects using these models. A working group of experts in complex systems modeling and economic evaluation was brought together to develop and jointly write guidance for the use of complex systems models for health economic analysis. The content of workshops was informed by a scoping review. A public health complex systems model for economic evaluation is defined as a quantitative, dynamic, non-linear model that incorporates feedback and interactions among model elements, in order to capture emergent outcomes and estimate health, economic and potentially other consequences to inform public policies. The guidance covers: when complex systems modeling is needed; principles for designing a complex systems model; and how to choose an appropriate modeling technique. This paper provides a definition to identify and characterize complex systems models for economic evaluations and proposes guidance on key aspects of the process for health economics analysis. This document will support the development of complex systems models, with impact on public health systems policy and decision making.
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Affiliation(s)
- Penny R. Breeze
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
| | - Hazel Squires
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
| | - Kate Ennis
- British Medical Journal Technology Appraisal GroupLondonUK
| | - Petra Meier
- MRC/CSO Social and Public Health Sciences UnitUniversity of GlasgowScotlandUK
| | - Kate Hayes
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
| | - Nik Lomax
- School of GeographyUniversity of LeedsLeedsUK
| | - Alan Shiell
- Department of Public HealthLaTrobe UniversityMelbourneAustralia
| | - Frank Kee
- Centre for Public HealthQueen's University BelfastBelfastUK
| | - Frank de Vocht
- Population Health SciencesBristol Medical SchoolUniversity of BristolBristolUK
- NIHR Applied Research Collaboration West (ARC West)BristolUK
| | - Martin O’Flaherty
- Department of Public Health, Policy and SystemsUniversity of LiverpoolLiverpoolUK
| | | | - Robin Purshouse
- Department of Automatic Control and Systems EngineeringUniversity of SheffieldSheffieldUK
| | | | - Peter J Dodd
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
| | - Mark Strong
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
| | | | - Richard Smith
- College of Medicine and HealthUniversity of ExeterExeterUK
| | - Andrew Briggs
- London School of Hygiene & Tropical MedicineLondonUK
| | - Lion Shahab
- Department of Behavioural Science and HealthUCLLondonUK
| | - Jo‐An Occhipinti
- Brain and Mind CentreUniversity of SydneyNew South WalesCamperdownAustralia
| | - Kenny Lawson
- Brain and Mind CentreUniversity of SydneyNew South WalesCamperdownAustralia
| | | | - Robert Smith
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
| | - Jennifer Boyd
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
- MRC/CSO Social and Public Health Sciences UnitUniversity of GlasgowGlasgowUK
| | | | | | | | | | - Amanda Karapici
- NIHR SPHRLondon School of Hygiene and Tropical MedicineLondonUK
| | - Franco Sassi
- Centre for Health Economics & Policy InnovationImperial College Business SchoolLondonUK
| | - Peter Scarborough
- Nuffield Department of Population HealthUniversity of OxfordOxfordshireOxfordUK
| | - Uwe Siebert
- Department of Public Health, Health Services Research and Health Technology AssessmentUMIT TIROL ‐ University for Health Sciences and TechnologyHall in TirolTyrolAustria
- Division of Health Technology Assessment and BioinformaticsONCOTYROL ‐ Center for Personalized Cancer MedicineInnsbruckAustria
- Center for Health Decision ScienceDepartments of Epidemiology and Health Policy & ManagementHarvard T.H. Chan School of Public HealthMassachusettsBostonUSA
- Program on Cardiovascular Research, Institute for Technology Assessment and Department of RadiologyMassachusetts General HospitalHarvard Medical SchoolMassachusettsBostonUSA
| | - Eric Silverman
- MRC/CSO Social and Public Health Sciences UnitUniversity of GlasgowGlasgowUK
| | - Luke Vale
- Health Economics GroupPopulation Health Sciences InstituteNewcastle UniversityNewcastleUK
| | - Cathal Walsh
- Health Research Institute and MACSIUniversity of LimerickLimerickIreland
| | - Alan Brennan
- School of Health and Related ResearchUniversity of SheffieldSheffieldUK
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3
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Murphy P, Glynn D, Dias S, Hodgson R, Claxton L, Beresford L, Cooper K, Tappenden P, Ennis K, Grosso A, Wright K, Cantrell A, Stevenson M, Palmer S. Modelling approaches for histology-independent cancer drugs to inform NICE appraisals: a systematic review and decision-framework. Health Technol Assess 2022; 25:1-228. [PMID: 34990339 DOI: 10.3310/hta25760] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The first histology-independent marketing authorisation in Europe was granted in 2019. This was the first time that a cancer treatment was approved based on a common biomarker rather than the location in the body at which the tumour originated. This research aims to explore the implications for National Institute for Health and Care Excellence appraisals. METHODS Targeted reviews were undertaken to determine the type of evidence that is likely to be available at the point of marketing authorisation and the analyses required to support National Institute for Health and Care Excellence appraisals. Several challenges were identified concerning the design and conduct of trials for histology-independent products, the greater levels of heterogeneity within the licensed population and the use of surrogate end points. We identified approaches to address these challenges by reviewing key statistical literature that focuses on the design and analysis of histology-independent trials and by undertaking a systematic review to evaluate the use of response end points as surrogate outcomes for survival end points. We developed a decision framework to help to inform approval and research policies for histology-independent products. The framework explored the uncertainties and risks associated with different approval policies, including the role of further data collection, pricing schemes and stratified decision-making. RESULTS We found that the potential for heterogeneity in treatment effects, across tumour types or other characteristics, is likely to be a central issue for National Institute for Health and Care Excellence appraisals. Bayesian hierarchical methods may serve as a useful vehicle to assess the level of heterogeneity across tumours and to estimate the pooled treatment effects for each tumour, which can inform whether or not the assumption of homogeneity is reasonable. Our review suggests that response end points may not be reliable surrogates for survival end points. However, a surrogate-based modelling approach, which captures all relevant uncertainty, may be preferable to the use of immature survival data. Several additional sources of heterogeneity were identified as presenting potential challenges to National Institute for Health and Care Excellence appraisal, including the cost of testing, baseline risk, quality of life and routine management costs. We concluded that a range of alternative approaches will be required to address different sources of heterogeneity to support National Institute for Health and Care Excellence appraisals. An exemplar case study was developed to illustrate the nature of the assessments that may be required. CONCLUSIONS Adequately designed and analysed basket studies that assess the homogeneity of outcomes and allow borrowing of information across baskets, where appropriate, are recommended. Where there is evidence of heterogeneity in treatment effects and estimates of cost-effectiveness, consideration should be given to optimised recommendations. Routine presentation of the scale of the consequences of heterogeneity and decision uncertainty may provide an important additional approach to the assessments specified in the current National Institute for Health and Care Excellence methods guide. FURTHER RESEARCH Further exploration of Bayesian hierarchical methods could help to inform decision-makers on whether or not there is sufficient evidence of homogeneity to support pooled analyses. Further research is also required to determine the appropriate basis for apportioning genomic testing costs where there are multiple targets and to address the challenges of uncontrolled Phase II studies, including the role and use of surrogate end points. FUNDING This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 76. See the NIHR Journals Library website for further project information.
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Affiliation(s)
- Peter Murphy
- Centre for Reviews and Dissemination, University of York, York, UK
| | - David Glynn
- Centre for Health Economics, University of York, York, UK
| | - Sofia Dias
- Centre for Reviews and Dissemination, University of York, York, UK
| | - Robert Hodgson
- Centre for Reviews and Dissemination, University of York, York, UK
| | - Lindsay Claxton
- Centre for Reviews and Dissemination, University of York, York, UK
| | - Lucy Beresford
- Centre for Reviews and Dissemination, University of York, York, UK
| | - Katy Cooper
- School of Health and Related Research (ScHARR) Technology Assessment Group, University of Sheffield, Sheffield, UK
| | - Paul Tappenden
- School of Health and Related Research (ScHARR) Technology Assessment Group, University of Sheffield, Sheffield, UK
| | - Kate Ennis
- School of Health and Related Research (ScHARR) Technology Assessment Group, University of Sheffield, Sheffield, UK
| | | | - Kath Wright
- Centre for Reviews and Dissemination, University of York, York, UK
| | - Anna Cantrell
- School of Health and Related Research (ScHARR) Technology Assessment Group, University of Sheffield, Sheffield, UK
| | - Matt Stevenson
- School of Health and Related Research (ScHARR) Technology Assessment Group, University of Sheffield, Sheffield, UK
| | - Stephen Palmer
- Centre for Health Economics, University of York, York, UK
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Cooper K, Tappenden P, Cantrell A, Ennis K. A systematic review of meta-analyses assessing the validity of tumour response endpoints as surrogates for progression-free or overall survival in cancer. Br J Cancer 2020; 123:1686-1696. [PMID: 32913287 PMCID: PMC7687906 DOI: 10.1038/s41416-020-01050-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 07/29/2020] [Accepted: 08/18/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Tumour response endpoints, such as overall response rate (ORR) and complete response (CR), are increasingly used in cancer trials. However, the validity of response-based surrogates is unclear. This systematic review summarises meta-analyses assessing the association between response-based outcomes and overall survival (OS), progression-free survival (PFS) or time-to-progression (TTP). METHODS Five databases were searched to March 2019. Meta-analyses reporting correlation or regression between response-based outcomes and OS, PFS or TTP were summarised. RESULTS The systematic review included 63 studies across 20 cancer types, most commonly non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and breast cancer. The strength of association between ORR or CR and either PFS or OS varied widely between and within studies, with no clear pattern by cancer type. The association between ORR and OS appeared weaker and more variable than that between ORR and PFS, both for associations between absolute endpoints and associations between treatment effects. CONCLUSIONS This systematic review suggests that response-based endpoints, such as ORR and CR, may not be reliable surrogates for PFS or OS. Where it is necessary to use tumour response to predict treatment effects on survival outcomes, it is important to fully reflect all statistical uncertainty in the surrogate relationship.
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Affiliation(s)
- Katy Cooper
- ScHARR, University of Sheffield, Sheffield, UK.
| | | | | | - Kate Ennis
- ScHARR, University of Sheffield, Sheffield, UK
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5
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Love-Koh J, Peel A, Rejon-Parrilla JC, Ennis K, Lovett R, Manca A, Chalkidou A, Wood H, Taylor M. Correction to: The Future of Precision Medicine: Potential Impacts for Health Technology Assessment. Pharmacoeconomics 2019; 37:117. [PMID: 30361887 PMCID: PMC6830397 DOI: 10.1007/s40273-018-0739-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The article The Future of Precision Medicine: Potential Impacts for Health Technology Assessment written by James Love‑Koh, Alison Peel Juan, Carlos Rejon‑Parrilla, KateAnastasia Chalkidou, Hannah Wood, Matthew Taylor was originally published electronically on the publisher's internet portal (currently Springer Link) on [13th July, 2018] with incorrect spelling of the co-author "Juan Carlos Rejon-Parilla". The correct spelling is "Juan Carlos Rejon-Parrilla".
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Affiliation(s)
- James Love-Koh
- York Health Economics Consortium, University of York, York, UK.
- Centre for Health Economics, University of York, Heslington, York, YO10 5DD, UK.
| | - Alison Peel
- York Health Economics Consortium, University of York, York, UK
| | | | - Kate Ennis
- York Health Economics Consortium, University of York, York, UK
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Rosemary Lovett
- National Institute for Health and Care Excellence, Manchester, UK
| | - Andrea Manca
- Centre for Health Economics, University of York, Heslington, York, YO10 5DD, UK
- Luxembourg Institute of Health, Strassen, Luxembourg
| | | | - Hannah Wood
- York Health Economics Consortium, University of York, York, UK
| | - Matthew Taylor
- York Health Economics Consortium, University of York, York, UK
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Love-Koh J, Peel A, Rejon-Parrilla JC, Ennis K, Lovett R, Manca A, Chalkidou A, Wood H, Taylor M. The Future of Precision Medicine: Potential Impacts for Health Technology Assessment. Pharmacoeconomics 2018; 36:1439-1451. [PMID: 30003435 PMCID: PMC6244622 DOI: 10.1007/s40273-018-0686-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
OBJECTIVE Precision medicine allows healthcare interventions to be tailored to groups of patients based on their disease susceptibility, diagnostic or prognostic information, or treatment response. We analysed what developments are expected in precision medicine over the next decade and considered the implications for health technology assessment (HTA) agencies. METHODS We performed a pragmatic literature search to account for the large size and wide scope of the precision medicine literature. We refined and enriched these results with a series of expert interviews up to 1 h in length, including representatives from HTA agencies, research councils and researchers designed to cover a wide spectrum of precision medicine applications and research. RESULTS We identified 31 relevant papers and interviewed 13 experts. We found that three types of precision medicine are expected to emerge in clinical practice: complex algorithms, digital health applications and 'omics'-based tests. These are expected to impact upon each stage of the HTA process, from scoping and modelling through to decision-making and review. The complex and uncertain treatment pathways associated with patient stratification and fast-paced technological innovation are central to these effects. DISCUSSION Innovation in precision medicine promises substantial benefits but will change the way in which some health services are delivered and evaluated. The shelf life of guidance may decrease, structural uncertainty may increase and new equity considerations will emerge. As biomarker discovery accelerates and artificial intelligence-based technologies emerge, refinements to the methods and processes of evidence assessments will help to adapt and maintain the objective of investing in healthcare that is value for money.
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Affiliation(s)
- James Love-Koh
- York Health Economics Consortium, University of York, York, UK.
- Centre for Health Economics, University of York, Heslington, York, YO10 5DD, UK.
| | - Alison Peel
- York Health Economics Consortium, University of York, York, UK
| | | | - Kate Ennis
- York Health Economics Consortium, University of York, York, UK
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Rosemary Lovett
- National Institute for Health and Care Excellence, Manchester, UK
| | - Andrea Manca
- Centre for Health Economics, University of York, Heslington, York, YO10 5DD, UK
- Luxembourg Institute of Health, Strassen, Luxembourg
| | | | - Hannah Wood
- York Health Economics Consortium, University of York, York, UK
| | - Matthew Taylor
- York Health Economics Consortium, University of York, York, UK
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Ennis K, Maus R. Kokomo family care: automating the clinical practice. Med Group Manage J 2001; 48:8-12. [PMID: 11458473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
A 14-physician family practice automated its prescription process, telephone messaging and laboratory test reporting to streamline its operations and contain costs.
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Affiliation(s)
- K Ennis
- American Health Network's Kokomo Family Care, Kokomo, Ind., USA.
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9
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Abstract
This paper reports on the findings from a quantitative research study of quality management in the Irish health-care sector. The study findings suggest that quality management is what hospitals require to become more cost-effective and efficient. The research also shows that the culture of health-care institutions must change to one where employees experience pride in their work and where all are involved and committed to continuous quality improvement. It is recommended that a shift is required from the traditional management structures to a more participative approach. Furthermore, all managers whether from a clinical or an administration background must understand one another's role in the organisation. Finally, for quality to succeed in the health-care sector, strong committed leadership is required to overcome tensions in quality implementation.
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Affiliation(s)
- K Ennis
- Mater Hospital, Dublin, Ireland
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10
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Julian D, Ennis K, Korenbrot JI. Birth and fate of proliferative cells in the inner nuclear layer of the mature fish retina. J Comp Neurol 1998; 394:271-82. [PMID: 9579393] [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]
Abstract
In teleost fish, unlike other vertebrates, the retina continues to grow throughout the animal's life both by stretching of the mature tissue and by the addition of new cells. Following larval development, new retinal cell birth is known to occur in a rim at the periphery of the mature retina and in the outer nuclear layer (ONL). We have now found that cell birth and proliferation also occurs in the inner nuclear layer (INL) of the mature fish retina. In rainbow trout (Onchoryncus mykiss), proliferative cells exist in the INL of fish of all ages, at least up to 2 years posthatching. The proliferative cells form clusters in the INL that align in radial columns, reaching from the inner to the outer plexiform layers. The density of proliferative cell clusters changes along the equatorial plane of the retina and is highest near both the nasal and temporal poles. Our data suggest that, after birth, the proliferative cells migrate away from the INL and into the ONL, with a half-time of about 3 days, and their cell bodies can be seen in the outer plexiform layer. Once they are in the ONL, the proliferative cells continue to divide and likely give rise to the precursor cells that differentiate into new rod photoreceptors.
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Affiliation(s)
- D Julian
- Department of Physiology, School of Medicine, University of California at San Francisco, 94143, USA
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Veitia R, Ion A, Barbaux S, Jobling MA, Souleyreau N, Ennis K, Ostrer H, Tosi M, Meo T, Chibani J, Fellous M, McElreavey K. Mutations and sequence variants in the testis-determining region of the Y chromosome in individuals with a 46,XY female phenotype. Hum Genet 1997; 99:648-52. [PMID: 9150734 DOI: 10.1007/s004390050422] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.6] [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: 02/04/2023]
Abstract
The testis-determining gene SRY (sex determining region, Y) is located on the short arm of the Y chromosome and consists of a single exon, the central third of which is predicted to encode a conserved motif with DNA binding/bending properties. We describe the screening of 26 patients who presented with 46,XY partial or complete gonadal dysgenesis for mutations in both the SRY open reading frame (ORF) and in 3.8 kb of Y-specific flanking sequences. DNA samples were screened by using the fluorescence-assisted mismatch analysis (FAMA) method. In two patients, de novo mutations causing complete gonadal dysgenesis were detected in the SRY ORF. One was a nonsense mutation 5' to the HMG box, whereas the other was a missense substitution located at the C terminus of the conserved motif and identical to one previously detected in an unrelated patient. In addition, two Y-specific polymorphisms were found 5' to the SRY gene, and a sequence variant was identified 3' to the SRY polyadenylation site. No duplications of the DSS region in 20 of these patients were detected.
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Affiliation(s)
- R Veitia
- Unité d'Immunogénétique Humaine, Institut Pasteur, Paris, France
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Silvestri G, Lotery A, Collins A, Ennis K, Hughes A. 1141 Linkage studies in a large family with central areolar choroidal dystrophy. Vision Res 1995. [DOI: 10.1016/0042-6989(95)90037-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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Grierson I, Nagasubramanian S, Edwards J, Millar LC, Ennis K. The effects of various levels of intraocular pressure on the rabbit's outflow system. Exp Eye Res 1986; 42:383-97. [PMID: 3709703 DOI: 10.1016/0014-4835(86)90032-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effects of various levels of intraocular pressure on the morphology of the rabbit outflow system were investigated. In a total of 20 rabbits, intraocular pressure was maintained at various levels between 0-50 mmHg in the experimental eye and at 20 mmHg in the control eye for 1 hr. Flow rates into the eyes were measured by following the movement of a miniscus through a calibrated capillary tube. Progressive increase in pressure lead to distension and enlargement of the ciliary cleft. The meshwork tissues stretched and distended, and the vessels of the angular aqueous plexus had pressure-sensitive giant vacuoles of their endothelium. These vessels were prone to closure at pressures of 30 mmHg and greater. Difficulties associated with quantitation of giant vacuoles in this species were discussed.
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