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Supporting patients to get the best from their osteoporosis treatment: a rapid realist review of what works, for whom, and in what circumstance. Osteoporos Int 2022; 33:2245-2257. [PMID: 35688897 PMCID: PMC9568441 DOI: 10.1007/s00198-022-06453-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/28/2022] [Indexed: 11/23/2022]
Abstract
Systematic reviews that examine effectiveness of interventions to improve medicines optimisation do not explain how or why they work. This realist review identified that interventions which effectively optimise medicines use in osteoporosis include opportunities to address patients' perceptions of illness and treatment and/or support primary care clinician decision making. INTRODUCTION In people with osteoporosis, adherence to medicines is poorer than other diseases and patients report follow-up is lacking, and multiple unmet information needs. We conducted a rapid realist review to understand what contextual conditions and mechanisms enable interventions to support osteoporosis medication optimisation. METHODS A primary search identified observational or interventional studies which aimed to improve medicines adherence or optimisation; a supplementary second search identified research of any design to gain additional insights on emerging findings. Extracted data was interrogated for patterns of context-mechanism-outcome configurations, further discussed in team meetings, informed by background literature and the Practicalities and Perception Approach as an underpinning conceptual framework. RESULTS We identified 5 contextual timepoints for the person with osteoporosis (identifying a problem; starting medicine; continuing medicine) and the practitioner and healthcare system (making a diagnosis and giving a treatment recommendation; reviewing medicine). Interventions which support patient-informed decision making appear to influence long-term commitment to treatment. Supporting patients' practical ability to adhere (e.g. by lowering treatment burden and issuing reminders) only appears to be helpful, when combined with other approaches to address patient beliefs and concerns. However, few studies explicitly addressed patients' perceptions of illness and treatment. Supporting primary care clinician decision making and integration of primary and secondary care services also appears to be important, in improving rates of treatment initiation and adherence. CONCLUSIONS We identified a need for further research to identify a sustainable, integrated, patient-centred, and cost- and clinically effective model of long-term care for people with osteoporosis.
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A critical synthesis of the role of the pharmacist in oral healthcare and management of medication-related osteonecrosis of the jaw. BDJ Open 2020; 6:13. [PMID: 32821431 PMCID: PMC7419284 DOI: 10.1038/s41405-020-0043-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE To consolidate extant published evidence in relation to the potential of integrating oral healthcare for patients at risk of developing medication-related osteonecrosis of the jaw (MRONJ). METHODS A critical synthesis and consolidation of five publications was undertaken. As a mechanism of situating the extant work within the context of primary healthcare provision, the Rainbow Model of Integrated Care was applied as a theoretical lens through which the conceptual findings could be collectively applied to practice. RESULTS The critical synthesis revealed a thematic emergence relating to both formative and normative integration. The most salient of these were the identification of limited shared clinical records, and disconnection of oral healthcare provision from patients' general medical care. The three levels of the Rainbow Model of Integrated Care reflected a series of issues for address. CONCLUSION In the context of collaborative, multi-disciplinary working for patients at risk of development of MRONJ, pharmacists are a professional group which this research reveals to be an underutilised resource. Reduction of oral health inequality at all levels of patient care is a key priority and this research highlights areas for address in relation to requirements for interprofessional education, optimal communication and policies reflective and facilitative of these.
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An audit of antimicrobial prescribing by dental practitioners in the north east of England and Cumbria. BMC Oral Health 2018; 18:206. [PMID: 30526584 PMCID: PMC6288968 DOI: 10.1186/s12903-018-0682-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 11/27/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Inappropriate prescribing of antimicrobials is a significant threat to global public health. In England, approximately 5% of all antimicrobial items are prescribed by dentists, despite the limited indications for their use in the treatment of oral infections in published clinical guidelines. The objective of this study was to survey antimicrobial prescribing by dental practitioners in North East England and Cumbria, identify educational and training needs and develop a self-assessment tool that can be used for Continued Professional Development by individual practitioners. METHODS During October 2016, 275 dental practitioners used a standardised form to record anonymous information about patients who had been prescribed antimicrobials. Clinical information and prescribing details were compared against clinical guidelines published by the Faculty of General Dental Practitioners UK. RESULTS Dental practitioners provided data on 1893 antimicrobial prescriptions. There was documented evidence of systemic spread, such as pyrexia in 18% of patients. Dentists recorded patients' pain (91.1% of patients), local lymph gland involvement (41.5%) gross diffuse swelling (55.5%) dysphagia (7.2%) and trismus (13.6%). Reasons for prescribing antimicrobials included patient expectations (25.8%), patient preference (24.8%), time pressures (10.9%), and patients uncooperative with other treatments (10.4%). The most commonly prescribed antimicrobials were amoxicillin, accounting for 61.2% of prescriptions, followed by metronidazole (29.9%). Most prescriptions for amoxicillin were for either 5 days (66.8%) or 7 days (29.6%) and most prescriptions for metronidazole were for a 5-day course (65.2%) or 7-day (18.6%) course. CONCLUSION In most cases, when an antimicrobial was prescribed, practitioners used the correct choice of agents and usually prescribed these at the correct dose. However, some evidence of suboptimal prescribing practices when compared to the Faculty of General Dental Practitioner guidelines were identified. The audit has identified training needs across the region and aided the development of Continued Professional Development sessions. Further work to identify barriers and facilitators for improving antimicrobial prescribing and determining appropriate methods to improve clinical practice are required.
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Oral health promotion in the community pharmacy: an evaluation of a pilot oral health promotion intervention. Br Dent J 2017; 223:521-525. [DOI: 10.1038/sj.bdj.2017.784] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2017] [Indexed: 12/20/2022]
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Prevalence of GMC performance assessments in the United Kingdom: a retrospective cohort analysis by country of medical qualification. BMC MEDICAL EDUCATION 2017; 17:67. [PMID: 28372544 PMCID: PMC5379692 DOI: 10.1186/s12909-017-0903-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 03/15/2017] [Indexed: 05/31/2023]
Abstract
BACKGROUND The demographics of doctors working in the UK are changing. The United Kingdom (UK) has voted to leave the European Union (EU) and there is heightened political discourse around the world about the impact of migration on healthcare services. Previous work suggests that foreign trained doctors perform worse than UK graduates in postgraduate medical examinations. We analysed the prevalence by country of primary medical qualification of doctors who were required to take an assessment by the General Medical Council (GMC) because of performance concerns. METHODS This was a retrospective cohort analysis of data routinely collected by the GMC. We compared doctors who had a GMC performance assessment between 1996 and 2013 with the medical register in the same period. The outcome measures were numbers experiencing performance assessments by country or region of medical qualification. RESULTS The rate of performance assessment varied significantly by place of medical qualification and by year; χ 2(17) = 188, p < 0.0001, pseudo-R2 = 15%. Doctors who trained outside of the UK, including those trained in the European Economic Area (EEA), were more likely to have a performance assessment than UK trained doctors, with the exception of South African trained doctors. CONCLUSIONS The rate of performance assessment varies significantly by place of medical qualification. This is the first study to explore the risk of performance assessment by individual places of medical qualification. While concern has largely focused on the competence of non-EEA, International Medical Graduates, we discuss implications for how to ensure European trained doctors are fit to practise before their medical licence in the UK is granted. Further research is needed to investigate whether these country effects hold true when controlling for factors like doctors' sex, age, length of time working in the UK, and English language skills. This will allow evidence-based decisions to be made around the regulatory environment the UK should adopt once it leaves the EU. Patients should be reassured that the vast majority of all doctors working in the UK are competent.
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E32 A 36 Month Longitudinal Magnetic Resonance Spectroscopy Study In Pre-manifest And Early Huntington Disease Subjects From The Track-hd Study. Journal of Neurology, Neurosurgery and Psychiatry 2014. [DOI: 10.1136/jnnp-2014-309032.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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M26 Teaching students to prescribe oxygen safely: the impact of an e-Learning module and BTS oxygen prescription section on oxygen prescribing by medical students taking Final MBBS examinations. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Q-motor – Quantitative motor assessments: Potential novel endpoints for clinical trials in pre-manifest and symptomatic Huntington's disease – 36 months longitudinal results from the multicenter TRACK-HD study. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.baga.2013.01.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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P238 Competence in, and Safety of, Oxygen Prescribing by Medical Students Taking Final MBBS as Assessed by Objective Structured Clinical Examination. Thorax 2012. [DOI: 10.1136/thoraxjnl-2012-202678.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
OBJECTIVES To evaluate in vivo brain metabolite differences in control subjects, individuals with premanifest Huntington disease (pre-HD), and individuals with early HD using ¹H magnetic resonance spectroscopy (MRS) and to assess their relationship with motor performance. METHODS Eighty-five participants (30 controls, 25 pre-HD, and 30 early HD) were recruited as part of the TRACK-HD study. Eighty-four were scanned at 3 T with single-voxel spectroscopy in the left putamen. Disease burden score was >220 among pre-HD individuals. Subjects underwent TRACK-HD motor assessment including Unified Huntington's Disease Rating Scale (UHDRS) motor scoring and a novel quantitative motor battery. Statistical analyses included linear regression and one-way analysis of variance. RESULTS Total N-acetylaspartate (tNAA), a neuronal integrity marker, was lower in early HD (∼15%) vs controls (p < 0.001). N-acetylaspartate (NAA), a constituent of tNAA, was lower in pre-HD (∼8%) and early HD (∼17%) vs controls (p < 0.05). The glial cell marker, myo-inositol (mI), was 50% higher in early HD vs pre-HD (p < 0.01). In early HD, mI correlated with UHDRS motor score (R² = 0.23, p < 0.05). Across pre-HD and early HD, tNAA correlated with performance on a tongue pressure task (R² = 0.30, p < 0.0001) and with disease burden score (R² = 0.17, p < 0.005). CONCLUSIONS We demonstrate lower putaminal tNAA in early HD compared to controls in a cross-section of subjects. A novel biomarker role for mI in early HD was also identified. These findings resolve disagreement in the literature about the role of MRS as an HD biomarker. We conclude that putaminal MRS measurements of NAA and mI are promising potential biomarkers of HD onset and progression.
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Tapping linked to function and structure in premanifest and symptomatic Huntington disease. Neurology 2010; 75:2150-60. [PMID: 21068430 DOI: 10.1212/wnl.0b013e3182020123] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE Motor signs are functionally disabling features of Huntington disease. Characteristic motor signs define disease manifestation. Their severity and onset are assessed by the Total Motor Score of the Unified Huntington's Disease Rating Scale, a categorical scale limited by interrater variability and insensitivity in premanifest subjects. More objective, reliable, and precise measures are needed which permit clinical trials in premanifest populations. We hypothesized that motor deficits can be objectively quantified by force-transducer-based tapping and correlate with disease burden and brain atrophy. METHODS A total of 123 controls, 120 premanifest, and 123 early symptomatic gene carriers performed a speeded and a metronome tapping task in the multicenter study TRACK-HD. Total Motor Score, CAG repeat length, and MRIs were obtained. The premanifest group was subdivided into A and B, based on the proximity to estimated disease onset, the manifest group into stages 1 and 2, according to their Total Functional Capacity scores. Analyses were performed centrally and blinded. RESULTS Tapping variability distinguished between all groups and subgroups in both tasks and correlated with 1) disease burden, 2) clinical motor phenotype, 3) gray and white matter atrophy, and 4) cortical thinning. Speeded tapping was more sensitive to the detection of early changes. CONCLUSION Tapping deficits are evident throughout manifest and premanifest stages. Deficits are more pronounced in later stages and correlate with clinical scores as well as regional brain atrophy, which implies a link between structure and function. The ability to track motor phenotype progression with force-transducer-based tapping measures will be tested prospectively in the TRACK-HD study.
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F14 Speeded tapping assesses progression of huntington's disease within one year—results from the track-HD study. J Neurol Psychiatry 2010. [DOI: 10.1136/jnnp.2010.222620.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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H06 Cross sectional and longitudinal 3T magnetic resonance spectroscopy in a TRACK-HD cohort of individuals with premanifest and early Huntington's disease. J Neurol Psychiatry 2010. [DOI: 10.1136/jnnp.2010.222653.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sensitivity of gait analysis to detect motor phenotype in pre-manifest and manifest Huntington's disease – cross-sectional results from the TRACK-HD Study. AKTUELLE NEUROLOGIE 2009. [DOI: 10.1055/s-0029-1238520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Finger tapping as an objective motor phenotype marker in pre-manifest and symptomatic Huntington's disease – cross-sectional results from the TRACK-HD Study. AKTUELLE NEUROLOGIE 2009. [DOI: 10.1055/s-0029-1238474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Quantitative motor phenotype assessment in pre-manifest and symptomatic Huntington's disease: tongue force analysis differentiates between disease stages and provides high phenotype correlation. Cross sectional results from the TRACK-HD Study. AKTUELLE NEUROLOGIE 2009. [DOI: 10.1055/s-0029-1238518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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On Chorea – quantitative and objective analysis – cross-sectional results of the TRACK-HD Study. AKTUELLE NEUROLOGIE 2009. [DOI: 10.1055/s-0029-1238519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Epithelial vs myofibroblast differentiation in immortal rat lung cell lines—modulating effects of bleomycin. Histochem Cell Biol 2005; 124:453-64. [PMID: 16187068 DOI: 10.1007/s00418-005-0048-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2005] [Indexed: 11/28/2022]
Abstract
Two alveolar epithelial cell lines R3/1 and L2 were screened by immunocytochemical and RT-PCR analysis of epithelial and mesenchymal/contractile marker proteins. R3/1 and L2 cells were tested for their sensitivity to bleomycin (BLM), an anticancer drug, which is proposed to induce changes in lung cell differentiation. Both epithelial cell lines exhibited a mixed phenotype consisting of epithelial (E-cadherin, aquaporin-5 and cytokeratin 8) and myofibroblast-like (vimentin, alpha-SMA and caveolin-3) properties suggesting that the cell lines are arrested in vitro at a certain developmental stage during epithelial-mesenchymal transition (EMT). BLM treatment of R3/1 cells resulted in a partial reversal of this process modifying the cells in an epithelial direction, e.g., upregulation of E-cadherin, aquaporin-5 and other lung epithelial antigens at the mRNA and protein level. L2 cells showed similar alterations following BLM exposure.Immunohistochemical investigation of lung tissue from two different animal models of BLM-induced fibrosis (mouse and rat), revealed no signs of EMT, e.g., myofibroblastic differentiation of alveolar epithelial cells in situ. Immunohistological analysis of tissue samples of the rat model showed a heterogeneous population of myofibroblasts (alpha-SMA+/caveolin-3+, alpha-SMA-/caveolin-3+, and alpha-SMA+/caveolin-3-). These results suggest that BLM, on one hand, induces fibrosis and on the other hand possibly suppresses EMT during fibrogenesis.
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Thyroxine treatment in patients with symptoms of hypothyroidism but thyroid function tests within the reference range: randomised double blind placebo controlled crossover trial. BMJ (CLINICAL RESEARCH ED.) 2001; 323:891-5. [PMID: 11668132 PMCID: PMC58535 DOI: 10.1136/bmj.323.7318.891] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To determine whether thyroxine treatment is effective in patients with symptoms of hypothyroidism but with thyroid function tests within the reference range, and to investigate the effect of thyroxine treatment on psychological and physical wellbeing in healthy participants. DESIGN Randomised double blind placebo controlled crossover trial. SETTING Outpatient clinic in a general hospital. PARTICIPANTS 25 patients with symptoms of hypothyroidism who had thyroid function tests within the reference range, and 19 controls. METHODS PARTICIPANTS were given thyroxine 100 microgram or placebo to take once a day for 12 weeks. Washout period was six weeks. They were then given the other to take once a day for 12 weeks. All participants were assessed physiologically and psychologically at baseline and on completion of each phase. MAIN OUTCOME MEASURES Thyroid function tests, measures of cognitive function and of psychological and physical wellbeing. RESULTS 22 patients and 19 healthy controls completed the study. At baseline, patients' scores on 9 out of 15 psychological measures were impaired when compared with controls. Patients showed a significantly greater response to placebo than controls in 3 out of 15 psychological measures. Healthy participants had significantly lower scores for vitality when taking thyroxine compared to placebo (mean (SD) 60 (17) v 73 (16), P<0.01). However, patients' scores from psychological tests when taking thyroxine were no different from those when taking placebo except for a poorer performance on one visual reproduction test when taking thyroxine. Serum concentrations of free thyroxine increased and those of thyroid stimulating hormone decreased in patients and controls while they were taking thyroxine, confirming compliance with treatment. Although serum concentrations of free triiodothyronine increased in patients and controls taking thyroxine, the difference between the response to placebo and to thyroxine was significant only in the controls. CONCLUSIONS Thyroxine was no more effective than placebo in improving cognitive function and psychological wellbeing in patients with symptoms of hypothyroidism but thyroid function tests within the reference range. Thyroxine did not improve cognitive function and psychological wellbeing in healthy participants.
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Characterization and localization of the genes for mouse proteinase-3 (Prtn3) and neutrophil elastase (Ela2). CYTOGENETICS AND CELL GENETICS 2000; 83:104-8. [PMID: 9925946 DOI: 10.1159/000015144] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Proteinase-3 (PR-3) and neutrophil elastase (NE) are polymorphonuclear leukocyte serine proteinases that degrade extracellular matrix proteins including elastin and appear to be involved in the pathogenesis of several diseases characterized by tissue destruction most notably emphysema and Wegener's granulomatosis. In this report we characterize and compare the mouse PR-3 and NE genes and establish by FISH analysis a common location on mouse chromosome 10C2. Each gene consists of five exons and four introns conserving the typical granule-associated serine proteinase gene structure. The mouse PR-3 gene (Prtn3) is approximately 3.7 kb and is within 2.2 kb of the smaller (1.7 kb) NE gene (Ela2). The larger size of Prtn3 is accounted for by differences in intron sizes. A comparison between the mouse and human PR-3 cDNA reveals 73% homology, however, this drops to 60% when the amino acid sequences are compared. Homology between the mouse and human NE cDNA is 77% for both the cDNA and amino acid sequences. The catalytic triad and its placement are conserved among the four genes. The proximal promoter of mouse Prtn3 contains a TATA box, c-myb and an ets transcriptional site. As these are functional elements in the mouse Ela2 promoter they may also be important in the expression of Prtn3.
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Human proteinase-3 expression is regulated by PU.1 in conjunction with a cytidine-rich element. J Biol Chem 1996; 271:32392-402. [PMID: 8943304 DOI: 10.1074/jbc.271.50.32392] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Human proteinase-3 is one of three serine proteinases present in the azurophil granules of polymorphonuclear leukocytes along with elastase and cathepsin G. Proteinase-3 gene expression is confined to the promyelocytic stage of polymorphonuclear leukocyte maturation. The present investigation identifies elements responsible for this highly controlled tissue- and developmental-specific expression of proteinase-3. Within the first 200 base pairs of the proteinase-3 promoter, two elements were identified as important for expression, these elements at -101 and -190 confer the majority of the activity. The element at -101 has a PU.1 consensus. It binds a myeloid nuclear protein of approximately 45 kDa that "supershifts" with PU.1 antibody and is competed by the CD11b PU.1 element. The element at -190 has a core sequence of CCCCGCCC (CG element). The cytidines but not the guanidine are essential for promoter activity. The CG element binds a second nuclear protein with a molecular mass of approximately 40 kDa that is found in cells of myeloid lineage as well as non-myeloid HeLa cells. However, the proteinase-3 promoter is not active in HeLa cells which suggests that the CG element alone is not sufficient for proteinase-3 gene expression. Maturation of promyelocytic cells results in an inhibition of proteinase-3 gene expression and a reduction in nuclear protein binding to the PU.1 and CG elements. Similar elements occur in the elastase and cathepsin G promoters. Using the elastase and cathepsin G PU.1 and CG-like elements as probes results in identical band-shift patterns to that obtained with proteinase-3 PU.1 and CG elements. These data suggest that there is cooperative interaction between a PU.1 and a CG element with a consensus of CCCCXCCC and that they are important control elements for tissue- and developmental-specific expression of azurophil serine proteinases of polymorphonuclear leukocytes.
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Regulation of the transferrin-independent iron transport system in cultured cells. J Biol Chem 1991; 266:2997-3004. [PMID: 1993673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mammalian cells accumulate iron via the binding of transferrin to high affinity surface receptors, or through a transferrin-independent pathway which involves the uptake of iron-organic anion chelates by a membrane-based transport system. Previously we determined that the transferrin-independent transport system was present on a wide variety of cultured cells (Sturrock, A., Alexander, J., Lamb, J., Craven, C. M., and Kaplan, J. (1990) J. Biol. Chem. 265, 3139-3145). In this communication we demonstrate that the transferrin-independent iron uptake system is regulated differently than the transferrin-mediated pathway. The activity of the transferrin-independent system was unaffected by changes in cellular growth rate, induction of DNA synthesis and cell division, or depletion of cellular iron. Exposure of cells to ferric or ferrous iron, however, resulted in a time-dependent increase in transport activity, due to a change in Vmax with no change in Km. Increased transport activity was seen in a variety of cultured cell types, occurred in the presence of cycloheximide, and persisted for hours after removal of iron. The ability of other transition metals to induce changes in transport, or to compete with iron for accumulation by the transferrin-independent uptake system, was critically dependent on the composition of the media in which the cells were incubated. Metals such as Cu2+ or Zn2+, but not Cd2+ or Mn2+, when dissolved in a balanced salt solution buffered with 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, induced changes in the transferrin-independent iron transport system. The same metals which induced changes in transport were ineffective in media containing amino acids, ascorbate, or N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine. The Vmax of the transferrin-independent iron transport system was also elevated by increases in intracellular Ca2+. The effect of iron on transport activity, however, did not result from an iron-induced release of intracellular Ca2+. These results suggest a novel form of regulation in which the presence of extracellular iron induces the appearance of previously cryptic transporters and thus accelerates the clearance of potentially toxic molecules.
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Characterization of a transferrin-independent uptake system for iron in HeLa cells. J Biol Chem 1990; 265:3139-45. [PMID: 2105943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
HeLa cells incubated in serum-free medium accumulated 59Fe ("non-transferrin iron") when incubated with either 59Fe-citrate, 59Fe-nitrilotriacetate, or 59Fe dissolved in Tricine ascorbate. Accumulation of iron was time-, concentration-, and Ca2+-dependent and was saturable. Uptake of non-transferrin (non-Tf) iron was transferrin-independent because of the fact that uptake occurred at pH 5.5, a pH at which transferrin binds iron poorly and at which transferrin is not internalized by cells. Uptake of non-Tf iron was less affected than uptake of transferrin iron by 1) exposure of cells to trypsin, a maneuver that cleaves Tf receptors, or 2) incubation of cells with phenylarsine oxide, an agent that inhibits both fluid- and receptor-mediated internalization. After exposure of cells to non-Tf iron at 37 degrees C, most of the cell-associated radioactivity was recovered in heme and ferritin, demonstrating that iron gained access to intracellular compartments and was not simply adsorbed to the cell surface. Uptake of non-Tf iron could be partially blocked by Cu2+ in a dose-dependent manner, while the accumulation of transferrin-bound iron was unaffected by Cu2+. Other transition metals, such as Zn2+, Cd2+, and Mn2+ were able to inhibit the uptake of non-Tf iron to different degrees. The accumulation of 109Cd was inhibited by incubation of cells with non-Tf iron, Cu2+, or Mn2+. The extent of inhibition was concentration- and metal-dependent. A number of cultured cell lines including HeLa, human skin fibroblasts, and Chinese hamster ovary cells demonstrated uptake of non-Tf iron and 109Cd. Additionally, an endosome acidification mutant of Chinese hamster ovary cells, which exhibited an increase in non-Tf iron uptake, also exhibited an increase in the uptake of Cd2+. These observations suggest that the characteristics of the non-Tf iron transport system in HeLa cells are similar if not identical to those reported for perfused rat liver (Wright, T. L., Brissot, P., Ma, W.-L., and Weisiger, P. A. (1986) J. Biol. Chem. 261, 10909-10914) and suggest the existence of a family of transition metal transport systems, each with a different metal specificity.
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Increased elastin production by progeria skin fibroblasts is controlled by the steady-state levels of elastin mRNA. J Invest Dermatol 1988; 90:643-7. [PMID: 3361140 DOI: 10.1111/1523-1747.ep12560800] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Hutchinson-Gilford progeria is a unique, rare disease with markedly accelerated aging. The average lifespan of affected individuals is 12 years. Although the biochemical basis of the syndrome is unknown, its influence appears to be primarily upon mesodermal tissues. Characteristics such as the altered appearance of the skin and the extensive and fatal involvement of the cardiovascular system led us to study elastin production in cultured skin fibroblasts from three progeroid individuals. We found tropoelastin production by progeroid cells was elevated six- to nine-fold at the protein and mRNA levels, while relative collagen synthesis was similar to control strains. There was little difference between progeroid and normal cells in expression of total protein or in total cellular mRNA content. Western blot analysis of tropoelastin from progeroid fibroblasts confirmed increased production of elastin but revealed no gross changes in the molecular mass. The significant increase in tropoelastin expression lends support to the concept that progeria results from a mesenchymal dysplasia, and offers a possible biochemical marker for the phenotype.
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