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Macuda T, Johnston K, Timney B. A direct estimate of the size of the illusory spots in the Hermann Grid Illusion. J Vis 2010. [DOI: 10.1167/3.9.754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Johnston K, Timney B, Leung D, Khan S. Alcohol reduces simultaneous contrast effects in human vision. J Vis 2010. [DOI: 10.1167/2.7.208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Khan S, Johnston K, Timney B. Dark adaptation functions and increment thresholds following alcohol ingestion. J Vis 2010. [DOI: 10.1167/1.3.455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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McCrory P, Meeuwisse W, Johnston K, Dvorak J, Aubry M, Molloy M, Cantu R. Consensus Statement on Concussion in Sport – the 3rd International Conference on Concussion in Sport held in Zurich, November 2008. SOUTH AFRICAN JOURNAL OF SPORTS MEDICINE 2009. [DOI: 10.17159/2413-3108/2009/v21i2a296] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
No Abstract.
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McCrory P, Meeuwisse W, Johnston K, Dvorak J, Aubry M, Molloy M, Cantu R. Consensus Statement on Concussion in Sport – the 3rd International Conference on Concussion in Sport held in Zurich, November 2008. SOUTH AFRICAN JOURNAL OF SPORTS MEDICINE 2009. [DOI: 10.17159/2078-516x/2009/v21i2a296] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
No Abstract.
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McCrory P, Meeuwisse W, Johnston K, Dvorak J, Aubry M, Molloy M, Cantu R. Consensus statement on Concussion in Sport--the 3rd International Conference on Concussion in Sport held in Zurich, November 2008. J Sci Med Sport 2009; 12:340-51. [PMID: 19362052 DOI: 10.1016/j.jsams.2009.02.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Depiazzi J, Johnston K, Anastas C. Pelvic floor muscle training in adolescent females with cystic fibrosis. J Cyst Fibros 2008. [DOI: 10.1016/s1569-1993(08)60275-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Allen AH, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Neveling R, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, Van de Wiele J, van Oers WTH, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, Zeps V. Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering. PHYSICAL REVIEW LETTERS 2007; 99:092301. [PMID: 17930999 DOI: 10.1103/physrevlett.99.092301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Indexed: 05/25/2023]
Abstract
We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A(n) provides a direct probe of the imaginary component of the 2gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.
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Trahair TN, Vowels MR, Johnston K, Cohn RJ, Russell SJ, Neville KA, Carroll S, Marshall GM. Long-term outcomes in children with high-risk neuroblastoma treated with autologous stem cell transplantation. Bone Marrow Transplant 2007; 40:741-6. [PMID: 17724446 DOI: 10.1038/sj.bmt.1705809] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We retrospectively analysed the outcomes of children transplanted for high-risk neuroblastoma (NB) at a single institution predominantly transplanted with total body irradiation and chemotherapy. The aims of this study were to determine the prognostic impact of clinical and biological features and to document long-term health outcomes. Forty patients were transplanted with a single unpurged autograft. Fourteen patients died from disease progression and two from late complications of treatment. Twenty-three patients are alive at a median of 4.6 years from diagnosis. Kaplan-Meier estimates of overall survival at 2, 5 and 10 years are 76+/-7.0, 60.2+/-8.4 and 54.7+/-9.3% following transplant. Response to induction therapy was significantly associated with survival (P<0.01). Long-term complications included growth (100%) and pubertal failure (83%), hearing impairment (73%), orthopaedic complications (63%), renal impairment (47%) and thyroid abnormalities (36%). Intrinsic and acquired resistance to chemotherapy remains the major obstacle to improving outcomes in high-risk NB. Although patients with chemo-sensitive disease are less likely to experience a relapse, substantial therapy-related toxicities result in poor long-term health outcomes for survivors.
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Selwood A, Johnston K, Katona C, Lyketsos C, Livingston G. Systematic review of the effect of psychological interventions on family caregivers of people with dementia. J Affect Disord 2007; 101:75-89. [PMID: 17173977 DOI: 10.1016/j.jad.2006.10.025] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 09/19/2006] [Accepted: 10/31/2006] [Indexed: 10/23/2022]
Abstract
BACKGROUND Caregivers of people with dementia are at high risk of psychological morbidity and associated breakdown in care. Many psychologically based interventions have been designed to help caregivers of people with dementia. More work is needed to identify which, if any, are helpful for such caregivers. METHOD We conducted a systematic review of the immediate and long term efficacy of different types of psychological interventions for the psychological health of caregivers of people with dementia, using standardized criteria, to assist clinicians in implementing rational, evidence-based management recommendations. We reviewed studies examining the effects of any therapy derived from a psychological approach that satisfied pre-specified criteria. Using the Oxford Centre for Evidence-Based Medicine criteria we rated the quality of each study, extracted data and gave overall ratings to different types of intervention. RESULTS We identified 244 references in our search of which 62 met our inclusion criteria. LIMITATIONS Our findings are limited by lack of good quality evidence, with only ten level 1 studies identified. CONCLUSIONS We found excellent evidence for the efficacy of six or more sessions of individual behavioral management therapy centered on the care recipient's behavior in alleviating caregiver symptoms both immediately and for up to 32 months. Teaching caregivers coping strategies either individually or in a group also appeared effective in improving caregiver psychological health both immediately and for some months afterwards. Group interventions were less effective than individual interventions. Education about dementia by itself, group behavioral therapy and supportive therapy were not effective caregiver interventions.
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van der Hoek K, Taylor SC, Peacock S, Johnston K, Melosky BL. Cost-effectiveness analysis (CEA) of third-line erlotinib therapy compared to best supportive care for advanced non-small cell lung cancer (NSCLC) in British Columbia (BC). J Clin Oncol 2007. [DOI: 10.1200/jco.2007.25.18_suppl.7678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
7678 Background: Erlotinib was approved for funding as a systemic therapy treatment for 3rd line management of advanced NSCLC by the BC Cancer Agency (BCCA) in April 2004. BCCA patient outcome and cost data are routinely collected to verify the therapeutic effectiveness and cost-effectiveness of systemic treatment policies. Methods: This was a pragmatic retrospective analysis of all patients who received 3rd line erlotinib compared to a historical group treated with 2nd-line docetaxel then no further active treatment, both according to BCCA protocol. The primary end-point was cost-effectiveness, measured in terms of cost per-life-year-gained. Secondary end-points included: median overall survival (MOS); overall survival (OS) at 1 year; and comparison to phase III efficacy results. Data was retrieved from the Cancer Agency Information System (CAIS) and Systemic Therapy Data Warehouse. Life-years- gained were calculated from the area under the survival function curve. CEA took the BCCA perspective and costs included all direct drug costs for treatment of advanced disease. Sensitivity analyses included varying life expectancy across its 95% CI, cost to the extremes of ranges, and start date for length of survival: method 1. progression after 2nd line therapy or 3 weeks post last dose of chemotherapy for control group and start date of erlotinib for treatment group; method 2. last date of 2nd line therapy for both groups Results: 75 control and 70 erlotinib patients were included in the analysis. Results are presented in the table . The Incremental Cost-Effectiveness Ratio (ICER) was $28,516 per life-year-gained under method 1, and $17,632 under method 2. The erlotinib group had similar 1-year OS compared to literature (36 vs. 31%). Conclusions: Erlotinib appears to be cost-effective in terms of life-expectancy under a range of assumptions. No significant financial relationships to disclose. [Table: see text]
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Williams C, Brunskill S, Altman D, Briggs A, Campbell H, Clarke M, Glanville J, Gray A, Harris A, Johnston K, Lodge M. Cost-effectiveness of using prognostic information to select women with breast cancer for adjuvant systemic therapy. Health Technol Assess 2007; 10:iii-iv, ix-xi, 1-204. [PMID: 16959170 DOI: 10.3310/hta10340] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES To investigate the cost-effectiveness of using prognostic information to identify patients with breast cancer who should receive adjuvant therapy. DATA SOURCES Electronic databases from 1980 through to February 2002. A survey of clinical practice in UK cancer centres and units. Large retrospective dataset containing data on prognostic factors, treatments and outcomes for women with early breast cancer treated in Oxford. REVIEW METHODS Between six and nine databases were searched by an information expert. Evidence-based methods were used to review and select those studies and the quality of each included paper was assessed using standard assessment tools reported in the literature or piloted and developed for this study. A survey of clinical practice in UK cancer centres and units was carried out to ensure that conclusions drawn from the report could be implemented. These data, along with the information gathered in the systematic reviews, informed the methodological approach adopted for the health economic modelling. An illustrative framework was developed for incorporating patient-level prediction within a health economic decision model. This framework was applied to a large retrospective dataset containing data on prognostic factors, treatments and outcomes for women with early breast cancer treated in Oxford. The data were used to estimate directly a parametric regression-based risk equation, from which a prognostic index was developed, and prognosis-specific estimates of the baseline breast cancer hazard could be observed. Published estimates of treatment effects, health service treatment costs and utilities were used to construct a decision analytic framework around this risk equation, thus enabling simulation of the effectiveness and cost-effectiveness of adjuvant therapy for all possible combinations of prognostic factors included in the model. RESULTS The lack of good-quality systematic reviews and well-conducted studies of prognostic factors in breast cancer is a striking finding. There are no registers of studies of prognostic factors or of reviews of prognostic studies. Many of the reviews used weak methods, primary studies are similar with poor methodology and reporting of results. In addition, there is much variation in patient populations, assay methods, analysis of results, definitions used and reporting of results. Most studies appear to be retrospective and some use inappropriate methods likely to inflate outcomes such as optimising cut points and failing to test the results in an independent population. Very few reviews used meta-analysis to conduct a pooled analysis and to provide an estimate of the average size of any association. Instead, most reviews relied on vote counting. Although many prognostic models for breast cancer have been published, remarkably few have been re-examined by independent groups in independent settings. The few validation studies have been carried out on ill-defined samples, sometimes of smaller size and short follow-up, and sometimes using different patient outcomes when validating a model. The evidence from the validation studies shows support for the prognostic value of the Nottingham Prognostic Index (NPI). No new prognostic factors have been shown to add substantially to those identified in the 1980s. Improvement of this index depends on finding factors that are as important as, but independent of, lymph node, stage and pathological grade. The NPI remains a useful clinical tool, although additional factors may enhance its use. We accepted that hormone receptor status (ER) for hormonal therapy such as tamoxifen and prediction of response to trastuzumab by HER2 did not require systematic review, as the mechanism of action of these drugs requires intact receptors. There was no clear evidence that other factors were useful predictors of response and survival. The survey confirmed pathological nodal status, tumour grade, tumour size and ER status as the most clinically important factors for consideration when selecting women with early breast cancer for adjuvant systemic therapy in the UK. The protocols revealed that although UK cancer centres appear to be using the same prognostic and predictive factors when selecting women to receive adjuvant therapy, much variation in clinical practice exists. Some centres use protocols based upon the NPI whereas others do not use a single index score. Within NPI and non-NPI users, between-centre variability exists in guidelines for women for whom the benefits are uncertain. Consensus amongst units appears to be greatest when selecting women for adjuvant hormone therapy with the decision based primarily upon ER or progesterone receptor status rather than combinations of a number of factors. Guidelines as to who should receive adjuvant chemotherapy, however, were found to be much less uniform. Searches of the literature revealed only five published papers that had previously examined the cost-effectiveness of using prognostic information for clinical decision-making. These studies were of varying quality and highlight the fact that economic evaluation in this area appears still to be in its infancy. By combining methodologies used in determining prognosis with those used in health economic evaluation, it was possible to illustrate an approach for simulating the effectiveness (survival and quality-adjusted survival) and the cost-effectiveness associated with the decision to treat individual women or groups of women with different prognostic characteristics. The model showed that effectiveness and cost-effectiveness of adjuvant systemic therapy have the potential to vary substantially depending upon prognosis. For some women therapy may prove very effective and cost-effective, whereas for others it may actually prove detrimental (i.e. the reductions in health-related quality of life outweigh any survival benefit). CONCLUSIONS Outputs from the framework constructed using the methods described here have the potential to be useful for clinicians, attempting to determine whether net benefits can be obtained from administering adjuvant therapy for any presenting woman; and also for policy makers, who must be able to determine the total costs and outcomes associated with different prognosis based treatment protocols as compared with more conventional treat all or treat none policies. A risk table format enabling clinicians to look up a patient's prognostic factors to determine the likely benefits (survival and quality-adjusted survival) from administering therapy may be helpful. For policy makers, it was demonstrated that the model's output could be used to evaluate the cost-effectiveness of different treatment protocols based upon prognostic information. The framework should also be valuable in evaluating the likely impact and cost-effectiveness of new potential prognostic factors and adjuvant therapies.
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Cantu RC, Aubry M, Dvorak J, Graf-Baumann T, Johnston K, Kelly J, Lovell M, McCrory P, Meeuwisse W, Schamasch P, Kevin M, Bruce SL, Ferrara MS, Kelly JP, McCrea M, Putukian M, McLeod TCV. Overview of concussion consensus statements since 2000. Neurosurg Focus 2006; 21:E3. [PMID: 17112193 DOI: 10.3171/foc.2006.21.4.4] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
More refereed publications on sports-related concussion have appeared since 2000 than in all previous years combined. Three international consensus statements, documents from the National Athletic Trainers' Association (NATA) and the American College of Sports Medicine (ACSM), and entire issues of the Clinical Journal of Sport Medicine and the Journal of Athletic Training have been devoted to this subject. The object of this article is to critique the consensus statements and NATA and ACSM documents, pointing out areas of controversy.
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Carson J, Tator C, Johnston K, Kissick J, Purcell L, Hunt B. New guidelines for concussion management. CANADIAN FAMILY PHYSICIAN MEDECIN DE FAMILLE CANADIEN 2006; 52:756-7. [PMID: 16812967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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Boxer AL, Kramer JH, Johnston K, Goldman J, Finley R, Miller BL. Executive dysfunction in hyperhomocystinemia responds to homocysteine-lowering treatment. Neurology 2006; 64:1431-4. [PMID: 15851736 DOI: 10.1212/01.wnl.0000158476.74580.a8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
An elevated serum homocysteine level is a risk factor for the development of cognitive impairment. Reported is a late-onset case of hyperhomocystinemia due to a vitamin B12 metabolic deficit (cobalamin C) with cognitive impairment, primarily in frontal/executive function. After homocysteine-lowering therapy, the patient's functional and neuropsychological status improved in conjunction with a decrease in leukoariosis on his MRI scan. These findings suggest that homocysteine-related cognitive impairment may be partially reversible.
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Dawber M, Lichtensteiger C, Cantoni M, Veithen M, Ghosez P, Johnston K, Rabe KM, Triscone JM. Unusual behavior of the ferroelectric polarization in PbTiO3/SrTiO3 superlattices. PHYSICAL REVIEW LETTERS 2005; 95:177601. [PMID: 16383870 DOI: 10.1103/physrevlett.95.177601] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Revised: 07/29/2005] [Indexed: 05/05/2023]
Abstract
Artificial PbTiO3/SrTiO3 superlattices were constructed using off-axis rf magnetron sputtering. X-ray diffraction and piezoelectric atomic force microscopy were used to study the evolution of the ferroelectric polarization as the ratio of PbTiO3 to SrTiO3 was changed. For PbTiO3 layer thicknesses larger than the 3-unit cell SrTiO3 thickness used in the structure, the polarization is found to be reduced as the thickness is decreased. This observation confirms the primary role of the depolarization field in the polarization reduction in thin films. For the samples with ratios of PbTiO3 to SrTiO3 of less than one, a surprising recovery of ferroelectricity that cannot be explained by electrostatic considerations was observed.
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Corbett S, Strole J, Johnston K, Swenson E, Weixiong Lu. Laser direct exposure of photodefinable polymer masks using shaped-beam optics. ACTA ACUST UNITED AC 2005. [DOI: 10.1109/tepm.2005.857662] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Hawthorne Allen A, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, MacLachlan GA, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Nakos M, Neveling R, Niccolai S, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, van de Wiele J, van Oers W, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, Zeps V. Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment. PHYSICAL REVIEW LETTERS 2005; 95:092001. [PMID: 16197209 DOI: 10.1103/physrevlett.95.092001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Indexed: 05/04/2023]
Abstract
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.
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Taylor P, Champness J, Given-Wilson R, Johnston K, Potts H. Impact of computer-aided detection prompts on the sensitivity and specificity of screening mammography. Health Technol Assess 2005; 9:iii, 1-58. [PMID: 15717938 DOI: 10.3310/hta9060] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES To determine the value of computer-aided detection (CAD) for breast cancer screening. DESIGN Two sets of mammograms with known outcomes were used in two studies. Participants in both studies read the films with and without the benefit of a computer aid. In both studies, the order of reading sessions was randomised separately for each reader. The first set of 180 films, used in study 1, included 20 false-negative interval cancers and 40 screen-detected cancers. The second set of 120 films, used in study 2, was designed to be favourable to CAD: all 44 cancer cases had previously been missed by a film reader and cancers prompted by CAD were preferentially included. SETTING The studies were conducted at five UK screening centres between January 2001 and April 2003. PARTICIPANTS Thirty radiologists, five breast clinicians and 15 radiographers participated. INTERVENTIONS All cases in the trial were digitised and analysed using the R2 ImageChecker version 2.2. Participants all received training on the use of CAD. In the intervention condition, participants interpreted cases with a prompt sheet on which regions of potential abnormality were indicated. MAIN OUTCOME MEASURES The sensitivity and specificity of participants were measured in both intervention and control conditions. RESULTS No significant difference was found for readers' sensitivity or specificity between the prompted and unprompted conditions in study 1 [95% confidence index (CI) for sensitivity with and without CAD is 0.76 to 0.80, for specificity it is 0.81 to 0.86 without CAD and 0.81 to 0.87 with CAD]. No statistically significant difference was found between the sensitivity and specificity of different groups of film reader (95% CI for unprompted sensitivity of radiologists was 0.75 to 0.81, for radiographers it was 0.71 to 0.81, prompted sensitivity was 0.76 to 0.81 for radiologists and 0.69 to 0.79 for radiographers). Thirty-five readers participated in study 2. Sensitivity was improved in the prompted condition (0.81 from 0.78) but the difference was slightly below the threshold for statistical significance (95% CI for the difference -0.003 to 0.064). Specificity also improved (0.87 from 0.86); again, the difference was not significant at 0.05 (95% CI -0.003 to 0.034). A cost-effectiveness analysis showed that computer prompting increases cost. CONCLUSIONS No significant improvement in film readers' sensitivity or specificity or gain in cost-effectiveness was established in either study. This may be due to the system's low specificity, its relatively poor sensitivity for subtle cancers or the fact the prompts cannot serve as aids to decision-making. Readers may have been better able to make use of the prompts after becoming more accustomed to working with them. Prompts may have an impact in routine use that is not detectable in an experimental setting. Although the case for CAD as an element of the NHS Breast Screening Programme is not made here, further research is required. Evaluations of new CAD tools in routine use are underway and their results should be given careful attention.
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Taylor P, Given-Wilson R, Champness J, Potts HWW, Johnston K. Assessing the impact of CAD on the sensitivity and specificity of film readers. Clin Radiol 2005; 59:1099-105. [PMID: 15556592 DOI: 10.1016/j.crad.2004.04.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Revised: 04/14/2004] [Accepted: 04/14/2004] [Indexed: 11/21/2022]
Abstract
AIM To assess the impact of computer-aided detection (CAD) prompts on film readers' sensitivity and specificity. MATERIAL AND METHODS Thirty-five readers read 120 films, including 44 cancers, 40 of which were prompted. All readers looked at all cases with and without prompts. The sensitivity and specificity were calculated for each reader under each condition. RESULTS The sensitivity improved when CAD prompts were used (0.80 from 0.77). The difference was slightly below the threshold for statistical significance (95% CI for the difference is -0.0027-0.064). The specificity also improved (0.86 from 0.85), but not significantly. There was a significant improvement in sensitivity when readers' judgements were combined to simulate double reading, from 0.77 to 0.81. (95% CI for the difference is 0.014-0.077). CONCLUSIONS Analysis of prompted cancers that readers did and did not recall, found that cases were more likely to be correctly recalled if there were emphasized prompts, more prompts or if the case was harder. There was no statistically significant effect for type of abnormality or tumour size or for the performance, attitude or experience of the reader.
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Johnston K, Kennedy C, Murdoch I, Taylor P, Cook C. The cost-effectiveness of technology transfer using telemedicine. Health Policy Plan 2004; 19:302-9. [PMID: 15310665 DOI: 10.1093/heapol/czh035] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The high burden of disease in developing countries often makes it difficult for health systems in these countries to attain the same level of specialist skills as industrialized countries. Technology transfer is one way to improve specialist skills whilst at the same time reducing the burden of disease. This paper describes the use of teleophthalmology, a form of telemedicine, as a mode of technology transfer between the United Kingdom and South Africa. As the burden of eye disease in South Africa is high, the country cannot afford the level of ophthalmic specialization achieved in the UK. The paper estimates the cost-effectiveness of the technology transfer project in terms of a cost per Disability Adjusted Life Year (DALY) averted. We found the technology transfer project to be cost-effective in reducing the burden of eye disease, and that practitioners in South Africa also learned novel procedures that could help future patients and improve cost-effectiveness. Technology transfer using telemedicine is a cost-effective method that richer countries can employ to aid capacity building in the health care systems of poorer countries.
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Johnston K, Everling S. Neural activity in monkey prefrontal cortex during delayed-match-to-sample and conditional pro-saccade - anti-saccade tasks. J Vis 2004. [DOI: 10.1167/4.8.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Kinder A, Jorsh M, Johnston K, Dawes P. Somatization disorder--a defensive waste of NHS resources. Rheumatology (Oxford) 2004; 43:672-4. [PMID: 15103033 DOI: 10.1093/rheumatology/keh137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Taylor PM, Champness J, Given-Wilson RM, Potts HWW, Johnston K. An evaluation of the impact of computer-based prompts on screen readers' interpretation of mammograms. Br J Radiol 2004; 77:21-7. [PMID: 14988134 DOI: 10.1259/bjr/34203805] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The NHS Breast Screening Programme is changing working practices in response to increased workload and manpower shortages. Radiographers are being trained as film readers. Computer aids are being considered. We have evaluated the impact of prompts placed by the R2 ImageChecker 1000 on the sensitivity and specificity of film readers, including non-radiologist film readers. 30 radiologists, 5 breast clinicians and 15 radiographers each read 180 films, including 60 cancers (20 false negative interval cases and 40 screen detected cancers). Each reader read each case twice, once with and once without computer prompts. The order in which the reading sessions were carried out was randomized separately for each reader. 36 out of 40 screen-detected cases were prompted by the ImageChecker, a sensitivity of 90%. Eight out of 20 interval cases were prompted, a sensitivity of 40%. No significant difference was found for readers' sensitivity or specificity between the prompted and unprompted conditions. No significant difference was found between the sensitivity and specificity of the different groups of film reader. No difference in impact of prompts was found for well or poorly performing film readers. The result suggests that this version of the ImageChecker would not have a significant impact on the UK screening programme.
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Obeid OA, Johnston K, Emery PW. Plasma taurine and cysteine levels following an oral methionine load: relationship with coronary heart disease. Eur J Clin Nutr 2003; 58:105-9. [PMID: 14679374 DOI: 10.1038/sj.ejcn.1601755] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE To test the hypothesis that endogenous synthesis of taurine from methionine is impaired in people with coronary heart disease (CHD). DESIGN Nested case-control. SUBJECTS Indian Asian and white European males aged 35-60 y. Both racial group included patients with CHD and healthy controls. Samples from 20 subjects in each of the four groups were selected at random. INTERVENTION Fasting blood samples were taken before and 6 h after consumption of methionine (100 mg/kg body weight) MEASUREMENTS Plasma concentrations of taurine, cysteine, pyridoxal-5-phosphate and 4-pyridoxic acid. RESULTS Fasting plasma taurine values were higher in Indian Asian cases than controls, but not significantly different between European cases and controls. Postload taurine values were higher in cases than controls in both racial groups (P=0.002). Fasting plasma cysteine was higher in cases than controls (P=0.002) and higher in Indian Asians than Europeans (0.007), but there were no significant differences between any of the groups in postload cysteine values, nor in plasma pyridoxal-5-phosphate or 4-pyridoxic acid. CONCLUSIONS Taurine production from methionine was not impaired in patients with CHD, but fasting plasma cysteine was higher in CHD cases than controls.
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