39 research outputs found

    Physiological experimentations with the crayfish hindgut.

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    Abstract The purpose of the report is to describe dissection techniques for preparing the crayfish hindgut and to demonstrate how to make physiological recordings with a force transducer to monitor the strength of contraction. In addition, we demonstrate how to visually monitor peristaltic activity, which can be used as a bioassay for various peptides, biogenic amines and neurotransmitters. This preparation is amenable to student laboratories in physiology and for demonstrating pharmacological concepts to students. This preparation has been in use for over 100 years, and it still offers much as a model for investigating the generation and regulation of peristaltic rhythms and for describing the mechanisms underlying their modulation. The pharmacological assays and receptor sub-typing that were started over 50 years ago on the hindgut still contribute to research today. This robust preparation is well suited to training students in physiology and pharmacology. Protoco

    Physiological experimentations with the crayfish hindgut.

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    Abstract The purpose of the report is to describe dissection techniques for preparing the crayfish hindgut and to demonstrate how to make physiological recordings with a force transducer to monitor the strength of contraction. In addition, we demonstrate how to visually monitor peristaltic activity, which can be used as a bioassay for various peptides, biogenic amines and neurotransmitters. This preparation is amenable to student laboratories in physiology and for demonstrating pharmacological concepts to students. This preparation has been in use for over 100 years, and it still offers much as a model for investigating the generation and regulation of peristaltic rhythms and for describing the mechanisms underlying their modulation. The pharmacological assays and receptor sub-typing that were started over 50 years ago on the hindgut still contribute to research today. This robust preparation is well suited to training students in physiology and pharmacology. Protoco

    Pressure Relieving Support Surfaces for Pressure Ulcer Prevention (PRESSURE 2): Clinical and Health Economic Results of a Randomised Controlled Trial

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    Background Pressure ulcers (PUs) are complications of serious acute/chronic illness. Specialist mattresses used for prevention lack high quality effectiveness evidence. We aimed to compare clinical and cost effectiveness of 2 mattress types. Methods Multicentre, Phase III, open, prospective, parallel group, randomised controlled trial in 42 UK secondary/community in-patient facilities. 2029 high risk (acutely ill, bedfast/chairfast and/or Category 1 PU/pain at PU site) adult in-patients were randomised (1:1, allocation concealment, minimisation with random element) factors including: centre, PU status, facility and consent type. Interventions were alternating pressure mattresses (APMs) or high specification foam (HSF) for maximum treatment phase 60 days. Primary outcome was time to development of new PU Category ≥ 2 from randomisation to 30 day post-treatment follow-up in intention-to treat population. Trial registration: ISRCTN 01151335. Findings Between August 2013 and November 2016, we randomised 2029 patients (1016 APMs: 1013 HSF) who developed 160(7.9%) PUs. There was insufficient evidence of a difference between groups for time to new PU Category ≥ 2 Fine and Gray Model Hazard Ratio HR = 0.76, 95%CI0.56–1.04); exact P = 0.0890; absolute difference 2%). There was a statistically significant difference in the treatment phase time to event sensitivity analysis, Fine and Gray model HR = 0.66, 95%CI, 0.46–0.93; exact P = 0.0176); 2.6% absolute difference). Economic analyses indicate that APM are cost-effective. There were no safety concerns. Interpretation In high risk (acutely ill, bedfast/chairfast/Category 1 PU/ pain on a PU site) in-patients, we found insufficient evidence of a difference in time to PU development at 30-day final follow-up, which may be related to a low event rate affecting trial power. APMs conferred a small treatment phase benefit. Patient preference, low PU incidence and small group differences suggests the need for improved targeting of APMs with decision making informed by patient preference/comfort/rehabilitation needs and the presence of potentially modifiable risk factors such as being completely immobile, nutritional deficits, lacking capacity and/or altered skin/Category1 PU

    Pressure Relieving Support Surfaces: a Randomised Evaluation 2 (PRESSURE 2): using photography for blinded central endpoint review

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    Background PRESSURE 2 is a randomised evaluation of the clinical and cost-effectiveness of two types of mattress for the prevention of pressure ulcers (PUs). The primary clinical endpoint was time to development of a category ≥2 PU. The current ‘gold standard’ for PU identification is expert clinical assessment. Due to the mattress appearance, a blinded assessment of the endpoint is not possible. This poses a risk to the internal validity of the study. A possible approach is to use photographs of skin sites, with central blinded review. However, there are practical and scientific concerns including patients’ consent to photographs, burden of data collection, photograph quality, data completeness and comparison of photographs to the current ‘gold standard’. This paper reports the findings of the PRESSURE 2 photographic validation sub-study. Method Where consent was obtained, photographs were taken of all category ≥2 PUs on the first presentation to assess over-reporting, and for the assessment of under-reporting, a random sample of 10% patients had an assessment by an independent clinical assessor who also photographed two skin sites. The staff were trained in taking and transferring photographs using standardised procedures and equipment. A card included in the photograph recorded participant details and a ‘greyscale’ for correction of white balance during processing. Three blinded reviewers assessed the photographs and rated how confident they were in their assessment. Results The trial recruited 2029 patients; 85% consented to photography, and 532 photographs were received and used in the blinded central review. The level of confidence varied by skin classification with more confidence observed when the skin was assessed as being less severe than a category ≥2 PU. Overall, there was a very good reliability compared to the gold standard expert clinical assessment (87.8%, kappa 0.82). Conclusion Study findings have usefully informed the scientific and practical issues of blinded assessment of PU status to reducing the risk of bias in medical device trials. The reliability of central blinded expert photography was found to be ‘very good’ (PABAK). Photographs have been found to be an acceptable method of data validation for participants. Methods to improve the quality of photographs would increase the confidence in the assessments. Trial registration ISRCTN Registry ISRCTN01151335. Registered on 19 April 201

    006 Comparison of alitretinoin vs. psoralen plus ultraviolet A as first-line treatments for chronic severe hand eczema: results from the ALPHA trial

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    Severe chronic hand eczema resistant to topical corticosteroid treatment is an important cause of morbidity and occupational disability. There is uncertainty regarding the best treatment approach and currently no treatment pathway is generally accepted by UK dermatologists. The primary aim of the ALPHA trial was to compare alitretinoin and immersion psoralen plus ultraviolet A (PUVA) as a first-line therapy in terms of disease activity at 12 weeks after the planned start of treatment. We conducted a prospective, multicentre, open-label, two-arm parallel group, adaptive randomized controlled trial. The natural logarithm of the Hand Eczema Severity Index (HECSI) + 1 at 12 weeks after the planned start of treatment was chosen as the primary endpoint so the relative effect of treatment could be estimated. In total, 514 participants were required to detect a fold change of 1.3 (5% two-sided significance level, 80% power, 20% attrition). Participants were randomized 1 : 1 by minimization to alitretinoin or immersion PUVA for 12–24 weeks. The intention-to-treat population consisted of 441 participants: 220 (49.9%) allocated to alitretinoin and 221 (50.1%) to immersion PUVA. In total, 212 (96.4%) alitretinoin participants and 196 (88.7%) immersion PUVA participants received at least one dose. There was a statistically significant benefit of alitretinoin compared with immersion PUVA at 12 weeks, with an estimated fold change of 0.66 [95% confidence interval (CI) 0.52–0.82; P 7 days during first 12 weeks). Thus, twice-weekly attendance for PUVA was not received by most participants. However, this represents standard of care with ALPHA run as a pragmatic trial using standard-of-care settings for the interventions. A further limitation was that assessment of long-term effects of randomized treatments was complicated by permitted use of second-line treatments after the treatment phase; therefore, trial conclusions are for randomized treatments as first-line therapies. We conclude that, as a first-line therapy, patients on alitretinoin showed more rapid improvement and superiority than those treated with immersion PUVA at week 12, but this difference was not observed at later time points. Future studies will need to further address the long-term benefits of treatments given and complex treatment pathways

    Pressure RElieving Support SUrfaces: a Randomised Evaluation 2 (PRESSURE 2): study protocol for a randomised controlled trial

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    Background Pressure ulcers represent a major burden to patients, carers and the healthcare system, affecting approximately 1 in 17 hospital and 1 in 20 community patients. They impact greatly on an individual’s functional status and health-related quality of life. The mainstay of pressure ulcer prevention practice is the provision of pressure redistribution support surfaces and patient repositioning. The aim of the PRESSURE 2 study is to compare the two main mattress types utilised within the NHS: high-specification foam and alternating pressure mattresses, in the prevention of pressure ulcers. Methods/Design PRESSURE 2 is a multicentre, open-label, randomised, double triangular, group sequential, parallel group trial. A maximum of 2954 ‘high-risk’ patients with evidence of acute illness will be randomised on a 1:1 basis to receive either a high-specification foam mattress or alternating-pressure mattress in conjunction with an electric profiling bed frame. The primary objective of the trial is to compare mattresses in terms of the time to developing a new Category 2 or above pressure ulcer by 30 days post end of treatment phase. Secondary endpoints include time to developing new Category 1 and 3 or above pressure ulcers, time to healing of pre-existing Category 2 pressure ulcers, health-related quality of life, cost-effectiveness, incidence of mattress change and safety. Validation objectives are to determine the responsiveness of the Pressure Ulcer Quality of Life-Prevention instrument and the feasibility of having a blinded endpoint assessment using photography. The trial will have a maximum of three planned analyses with unequally spaced reviews at event-driven coherent cut-points. The futility boundaries are constructed as non-binding to allow a decision for stopping early to be overruled by the Data Monitoring and Ethics Committee. Discussion The double triangular, group sequential design of the PRESSURE 2 trial will provide an efficient design through the possibility of early stopping for demonstrating either superiority, inferiority of mattresses or futility of the trial. The trial optimises the potential for producing robust clinical evidence on the effectiveness of two commonly used mattresses in clinical practice earlier than in a conventional design

    A patient-reported pressure ulcer health-related quality of life instrument for use in prevention trials (PU-QOL-P): psychometric evaluation

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    Introduction: Pressure ulcer-specific patient-reported outcome (PRO) instruments should be used to inform patient care and provide a strong evidence base for interventions aimed at preventing pressure ulcers. The aim was to carry out a comprehensive evaluation of the psychometric properties of a PRO instrument designed to assess symptoms and functional outcomes in patients at high-risk of developing pressure ulcers, the PU-QOL-P instrument. Methods: We modified the original PU-QOL instrument to be suitable for patients at high risk of pressure ulcer development based on feedback from patients, specialist nurses and PRO methodologists. The modified PU-QOL-P instrument was administered to a sub-set of patients participating in the PRESSURE 2 trial. Patients completed PU-QOL-P and SF12 instruments at baseline, weeks 1 and 3, and 30 days post-treatment. We undertook psychometric evaluation of the modified PU-QOL-P to test scale targeting, scaling assumptions, reliability, validity and responsiveness. Results: The analysis sample consisted of 617 patients that completed both instruments at baseline. We found that the PU-QOL-P instrument, consisting of nine PU-specific outcomes: three symptom and six function scales, meets established criteria for reliability, construct validity, and responsiveness. Internal consistency reliability was high with all scale Cronbach alpha > 0.795 (range 0.795–0.970). The factor analysis mostly supported the six-function scale structure. Scaling assumptions were satisfied; all item-total correlations above 0.30. Convergent validity was confirmed by significant correlations between hypothesized scales as expected. PU-QOL-P scales were responsive to change: mean scale scores from baseline to 30 days post-treatment were statistically significant for all scales apart the daily activities scale (effect sizes ranged from moderate to high). As expected, worse symptoms and functioning was observed in patients who had a category 1 or 2 PU compared to patients who did not have a PU. Conclusions: The PU-QOL-P provides a standardised method for assessing pressure ulcer-specific symptoms and functional outcomes for quantifying the benefits of associated interventions from the patient’s perspective. It can be used in research with adults at risk of pressure ulcer development in all UK healthcare settings

    The Association Between a Home Reading Program and Young Children’s Early Reading Skill

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    The purpose of this study was to examine the effects of teaching parents to deliver a carefully sequenced reading program to their kindergarten children who were not receiving formal reading instruction in school. Forty-five children and their parents enrolled in a kindergarten in a university-sponsored primary school participated in the research. Approximately twice as many children who participated in the home reading program scored in the top quartile of the Woodcock Reading Mastery (WRMT-R) word identification and word attack subtests as might be expected based on the test norms, while the children in the control group approximated the expected norms. On curriculum-based measures, the average score of children in the home reading group was higher than 87% of the children in the control group. Finally, a multiple regression analysis revealed that a significant proportion of the variance in children’s posttest performance was associated with their pretest scores on the WRMT-R letter identification subtest scores, their knowledge of the phonemes introduced in the curriculum and the consistency with which their parents implemented the home reading program. The results are discussed relative to previous research in which teachers implemented the curriculum and the issues associated with utilizing parents as primary beginning reading teachers. In addition, limitations of this research and suggestions for future research are provided
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