142 research outputs found

    Rabbit Erythropoiesis in vitro

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    The erythropoietin (Ep) dose response of erythroid colony-forming units (CFU-e) and erythroid burst-forming units (BFU-e) from rabbit bone were similar to murine erythroid precursor Ep requirements. Bone marrow and peripheral blood contained a continuum of erythroid precursors at differing stages of maturation. The earliest BFU-e were assayed on day 10. CFU-e were observed in bone marrow, but not in peripheral blood. The most mature erythroid precursors observed in peripheral blood were intermediate BFU-e, assayed on day 5. A linear relationship exists between the number of nucleated bone marrow cells plated and the number of 3 day colonies and 10 day bursts observed. The 10 day bursts were composed of erythroid cells at all stages of maturation and these cells contained normal adult hemoglobins. The methylcellulose assay was then used to characterize the hemopoietic tissue in ossicles induced by demineralized allogeneic bone matrix (DBM) and to investigate the mechanisms of action of burst-promoting activity (BPA). DBM, implanted in muscle, induces the formation of an ossicle within which hemopoietic tissue develops. Analyses of ossicle marrow in vitro demonstrated the presence of committed hemopoietic precursors; colony-forming units in culture (CFU-c), CFU-e and BFU-e by 6 weeks postimplantation. The time courses of colony and burst formation by erythroid precursors in ossicle and femoral marrow were similar. Induction of hemolytic anemia by phenylhydrazine hydrochloride at six weeks post DBM implantation showed that the ossicle marrow was responsive to systemic erythropoietic stimuli The DBM implant is a unique model for studying the development of hemopoietic microenvironments within bone. Rabbit bone marrow conditioned media (BMCM) was found to contain potent erythroid BPA. In order to further characterize the mechanisms of action of BPA and to improve the quantitation or BPA, we studied the effects of BMCM on the number of bursts, cells per burst and 59Fe incorporation into heme. Examination of erythroid precursors at different maturational stages revealed that the sensitivity of erythroid precursors to BPA decreases with maturity. Delayed addition of BMCM to cultures demonstrated a requirement for BPA during the early stages of burst formation. BMCM did not enhance granulocyte/macrophage colony formation. The enhancement of heme synthesis by BMCM was routinely much greater (range, 7- to 109-fold) than the increase in burst number (range, 1- to 2-fold). The latter observation suggested that BPA might increase the size of bursts in addition to augmenting burst number. Simultaneous measurement of cell number and 59Fe incorporation in individual bursts showed a strong correlation between these parameters. In this experiment, the total enhancement of cell number and 59Fe incorporation was 6.6- and 8.0-fold, respectively. These results suggest that a major effect of BMCM BPA is to promote cell division during the early phase of burst formation

    A mission possible: towards a shared dialogic space for professional learning in UK higher education

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    In this paper, we have developed the concept of dialogic space to elaborate our view of the importance of creating future academic practice together in relationship with others in a higher education context. We see scope and potential for the dialogic space as a forum for ‘interthinking’ to engage the voices of stakeholders in contributing to the development of more democratic understandings about academic practice and reforms in higher education. In the paper, a vignette has been used as a methodological approach to illustrate the possibility of creating such dialogic space. At the end of the paper, wider implications of using dialogic space in professional learning in academic contexts have been discussed

    Characterization of disease course and remission in early seropositive rheumatoid arthritis: results from the TACERA longitudinal cohort study

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    Background: To characterise disease course and remission in a longitudinal observational study of newly diagnosed, initially treatment-naïve patients with seropositive rheumatoid arthritis (RA). Methods: Patients with early untreated seropositive RA were recruited from 28 UK centres. Multiple clinical and laboratory measures were collected every 3 months for up to 18 months. Disease activity was measured using the 28-joint Disease Activity Score with C-reactive protein (DAS28-CRP) and Simplified Disease Activity Index (SDAI). Logistic regression models examined clinical predictors of 6-month remission and latent class mixed models characterised disease course. Results: We enrolled 275 patients of whom 267 met full eligibility and provided baseline data. According to SDAI definition, 24.3% attained 6-month remission. Lower baseline Health Assessment Questionnaire (HAQ) and SDAI predicted 6-month remission (p = 0.013 and 0.011). Alcohol intake and baseline prescribing of methotrexate with a second disease-modifying antirheumatic drug (DMARD; vs monotherapy without glucocorticoids) were also predictive. Three distinct SDAI trajectory subpopulations emerged; corresponding to an inadequate responder group (6.5%), and higher and lower baseline activity responder groups (22.4% and 71.1%). Baseline HAQ and Short Form-36 Health Survey – Mental Component Score (SF-36 MCS) distinguished these groups. In addition, a number of baseline clinical predictors correlated with disease activity severity within subpopulations. Beneficial effects of alcohol intake were found across subpopulations. Conclusion: Three distinct disease trajectory subpopulations were identified. Differential effects of functional and mental well-being, alcohol consumption, and baseline RA medication prescribing on disease activity severity were found across subpopulations. Heterogeneity across trajectories cannot be fully explained by baseline clinical predictors. We hypothesise that biological markers collected early in disease course (within 6 months) may help patient management and better targeting of existing and novel therapies

    The practice educator as museum guide, art therapist or exhibition curator: a cross-disciplinary analysis of arts-based learning

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    The use of arts-based approaches in professional education in health and social care has gathered momentum in the last decade and their effectiveness has been well documented. There are helpful models in the education literature that begin to explain how these creative methods work in learning and practice, and that assert the significance of an emotional or affective level of learning. However, the process remains elusive, almost a ‘given’. A more cross-disciplinary analysis of affective learning is needed to guide arts-based methods and more robust evaluation of their use in health and social care education and practice. This paper identifies different roles that can be taken by the practice educator with a review of those theoretical models of affective learning that underpin them to help understand how and why arts-based approaches are effective

    "Then you get a teacher" - Guidelines for excellence in teaching

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    Background: Current literature calls for the explicit teaching to health-science educators of the skills, knowledge and dispositions that are required for successful teaching in higher education. Aims: This paper draws on evidence from an Oral Hygiene department at a South African university in order to illustrate these teaching-competency needs. Insights from the evidence are synthesised with current literature regarding best teaching practice, in support of an appropriate framework for the development of teaching competencies to health-science educators. Description: A qualitative approach, using a case study, was adopted. The cohort comprised fifteen students in the first-year Oral Hygiene cohort class and the ten educators who taught their programme. Data was collected through semistructured interviews and open-ended questionnaires. The topics that emerged from the combined analysis of the interviews and the questionnaires were organised into a grid so that common themes could be identified. Current literature regarding teaching and learning was used as a framework for interpreting the empirical evidence, from which three categories emerged. The first category included suggestions from students regarding what to do to teach better. A review of the literature indicates that these competencies can be effectively learnt from self-help guides. The second category included requests for skills development. Literature review suggests that these might effectively be learnt from single-event workshops facilitated by more able peers. Responses in the final category highlighted the need for an underpinning theory of teaching and learning, and signalled the need for a more theoretically grounded and detailed approach to teacher development. Conclusion: The framework developed from the empirical study and current literature makes it possible for individual clinical teachers, and staff developers, to construct teaching-competency development plans that are pertinent to individual teachers’ needs, relevant and practical, educationally sound, and cost-effective in terms of time and effort

    The ChatGPT Artificial Intelligence Chatbot: How Well Does It Answer Accounting Assessment Questions?

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    ChatGPT, a language-learning model chatbot, has garnered considerable attention for its ability to respond to users’ questions. Using data from 14 countries and 186 institutions, we compare ChatGPT and student performance for 28,085 questions from accounting assessments and textbook test banks. As of January 2023, ChatGPT provides correct answers for 56.5 percent of questions and partially correct answers for an additional 9.4 percent of questions. When considering point values for questions, students significantly outperform ChatGPT with a 76.7 percent average on assessments compared to 47.5 percent for ChatGPT if no partial credit is awarded and 56.5 percent if partial credit is awarded. Still, ChatGPT performs better than the student average for 15.8 percent of assessments when we include partial credit. We provide evidence of how ChatGPT performs on different question types, accounting topics, class levels, open/closed assessments, and test bank questions. We also discuss implications for accounting education and research

    Chinese students in a UK business school: hearing the student voice in reflective teaching and learning practice.

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    This paper presents the outcomes of a study carried out in 2001-2002 with nine postgraduate students from China, enrolled on taught master's programmes in a UK university business school. The aims of the research were to explore the development of the students' orientations to learning during their year of study in the UK, and to explore how the researcher's interactions with the study group contributed to her professional reflections and influenced her academic practice. The main conclusions of the project were that participants' underlying approaches to learning did not change substantially over the year, owing to the culturally implicit nature of UK academic conventions and that they experienced high levels of emotional isolation and loneliness, which affected their academic confidence
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