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1.
EClinicalMedicine ; 71: 102557, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38813441

RESUMO

Background: It was anticipated that recruitment to the Cavernous malformations: A Randomised Effectiveness (CARE) pilot randomised trial would be challenging. The trial compared medical management and surgery (neurosurgical resection or stereotactic radiosurgery) with medical management alone, for people with symptomatic cerebral cavernous malformation (ISRCTN41647111). Previous trials comparing surgical and medical management for intracranial vascular malformations failed to recruit to target. A QuinteT Recruitment Intervention was integrated during trial accrual, September 2021-April 2023 inclusive, to improve informed consent and recruitment. Methods: The QuinteT Recruitment Intervention combined iterative collection and analysis of quantitative data (28 trial site screening logs recording numbers/proportions screened, eligible, approached and randomised) and qualitative data (79 audio-recorded recruitment discussions, 19 interviews with healthcare professionals, 11 interviews with patients, 2 investigator workshops, and observations of study meetings, all subject to thematic, content or conversation analysis). We triangulated quantitative and qualitative data to identify barriers and facilitators to recruitment and how and why these arose. Working with the chief investigators and trial management group, we addressed barriers and facilitators with corresponding actions to improve informed consent and recruitment. Findings: Barriers identified included how usual care practices made equipoise challenging, multi-disciplinary teams sometimes overrode recruiter equipoise and logistical issues rendered symptomatic cavernoma diagnosis and assessment for stereotactic radiosurgery challenging. Facilitators identified included the preparedness of some neurosurgeons' to offer surgery to people otherwise offered medical management alone, multi-disciplinary team equipoise, and effective information provision presenting participation as a solution to equipoise regarding management. Actions, before and during recruitment, to improve inclusivity of site screening, approach and effectiveness of information provision resulted in 72 participants recruited following a 5-month extension, exceeding the target of 60 participants. Interpretation: QuinteT Recruitment Intervention insights revealed barriers and facilitators, enabling identification of remedial actions. Recruitment to a definitive trial would benefit from further training/support to encourage clinicians to be comfortable approaching patients to whom medical management is usually offered, and broadening the pool of neurosurgeons and multi-disciplinary team members prepared to offer surgery, particularly stereotactic radiosurgery. Funding: National Institute for Health and Care Research.

2.
J Nucl Med ; 64(9): 1478-1486, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37591540

RESUMO

Coronary 18F-sodium fluoride (18F-fluoride) uptake is a marker of both atherosclerotic disease activity and disease progression. It is currently unknown whether there are rapid temporal changes in coronary 18F-fluoride uptake and whether these are more marked in those with clinically unstable coronary artery disease. This study aimed to determine the natural history of coronary 18F-fluoride uptake over 12 mo in patients with either advanced chronic coronary artery disease or a recent myocardial infarction. Methods: Patients with established multivessel coronary artery disease and either chronic disease or a recent acute myocardial infarction underwent coronary 18F-fluoride PET and CT angiography, which was repeated at 3, 6, or 12 mo. Coronary 18F-fluoride uptake was assessed in each vessel by measuring the coronary microcalcification activity (CMA). Coronary calcification was quantified by measuring calcium score, mass, and volume. Results: Fifty-nine patients had chronic coronary artery disease (median age, 68 y; 93% male), and 52 patients had a recent myocardial infarction (median age, 65 y; 83% male). Reflecting the greater burden of coronary artery disease, baseline CMA values were higher in those with chronic coronary artery disease. Coronary 18F-fluoride uptake (CMA > 0) was associated with higher baseline calcium scores (294 Agatston units [AU] [interquartile range, 116-483 AU] vs. 72 AU [interquartile range, 8-222 AU]; P < 0.001) and more rapid progression of coronary calcification scores (39 AU [interquartile range, 10-82 AU] vs. 12 AU [interquartile range, 1-36 AU]; P < 0.001) than was the absence of uptake (CMA = 0). Coronary 18F-fluoride uptake did not markedly alter over the course of 3, 6, or 12 mo in patients with either chronic coronary artery disease or a recent myocardial infarction. Conclusion: Coronary 18F-fluoride uptake is associated with the severity and progression of coronary artery disease but does not undergo a rapid dynamic change in patients with chronic or unstable coronary artery disease. This finding suggests that coronary 18F-fluoride uptake is a temporally stable marker of established and progressive disease.


Assuntos
Calcinose , Doença da Artéria Coronariana , Infarto do Miocárdio , Isquemia Miocárdica , Humanos , Masculino , Idoso , Feminino , Doença da Artéria Coronariana/diagnóstico por imagem , Fluoretos , Cálcio , Coração , Infarto do Miocárdio/diagnóstico por imagem
3.
BMJ Open ; 13(8): e075187, 2023 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-37558454

RESUMO

INTRODUCTION: The top research priority for cavernoma, identified by a James Lind Alliance Priority setting partnership was 'Does treatment (with neurosurgery or stereotactic radiosurgery) or no treatment improve outcome for people diagnosed with a cavernoma?' This pilot randomised controlled trial (RCT) aims to determine the feasibility of answering this question in a main phase RCT. METHODS AND ANALYSIS: We will perform a pilot phase, parallel group, pragmatic RCT involving approximately 60 children or adults with mental capacity, resident in the UK or Ireland, with an unresected symptomatic brain cavernoma. Participants will be randomised by web-based randomisation 1:1 to treatment with medical management and with surgery (neurosurgery or stereotactic radiosurgery) versus medical management alone, stratified by prerandomisation preference for type of surgery. In addition to 13 feasibility outcomes, the primary clinical outcome is symptomatic intracranial haemorrhage or new persistent/progressive focal neurological deficit measured at 6 monthly intervals. An integrated QuinteT Recruitment Intervention (QRI) evaluates screening logs, audio recordings of recruitment discussions, and interviews with recruiters and patients/parents/carers to identify and address barriers to participation. A Patient Advisory Group has codesigned the study and will oversee its progress. ETHICS AND DISSEMINATION: This study was approved by the Yorkshire and The Humber-Leeds East Research Ethics Committee (21/YH/0046). We will submit manuscripts to peer-reviewed journals, describing the findings of the QRI and the Cavernomas: A Randomised Evaluation (CARE) pilot trial. We will present at national specialty meetings. We will disseminate a plain English summary of the findings of the CARE pilot trial to participants and public audiences with input from, and acknowledgement of, the Patient Advisory Group. TRIAL REGISTRATION NUMBER: ISRCTN41647111.


Assuntos
Neurocirurgia , Radiocirurgia , Adulto , Criança , Humanos , Estudos de Viabilidade , Projetos Piloto , Encéfalo , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
JAMA Cardiol ; 8(8): 755-764, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37379010

RESUMO

Importance: Recurrent coronary events in patients with recent myocardial infarction remain a major clinical problem. Noninvasive measures of coronary atherosclerotic disease activity have the potential to identify individuals at greatest risk. Objective: To assess whether coronary atherosclerotic plaque activity as assessed by noninvasive imaging is associated with recurrent coronary events in patients with myocardial infarction. Design, Setting, and Participants: This prospective, longitudinal, international multicenter cohort study recruited participants aged 50 years or older with multivessel coronary artery disease and recent (within 21 days) myocardial infarction between September 2015 and February 2020, with a minimum 2 years' follow-up. Intervention: Coronary 18F-sodium fluoride positron emission tomography and coronary computed tomography angiography. Main Outcomes and Measures: Total coronary atherosclerotic plaque activity was assessed by 18F-sodium fluoride uptake. The primary end point was cardiac death or nonfatal myocardial infarction but was expanded during study conduct to include unscheduled coronary revascularization due to lower than anticipated primary event rates. Results: Among 2684 patients screened, 995 were eligible, 712 attended for imaging, and 704 completed an interpretable scan and comprised the study population. The mean (SD) age of participants was 63.8 (8.2) years, and most were male (601 [85%]). Total coronary atherosclerotic plaque activity was identified in 421 participants (60%). After a median follow-up of 4 years (IQR, 3-5 years), 141 participants (20%) experienced the primary end point: 9 had cardiac death, 49 had nonfatal myocardial infarction, and 83 had unscheduled coronary revascularizations. Increased coronary plaque activity was not associated with the primary end point (hazard ratio [HR], 1.25; 95% CI, 0.89-1.76; P = .20) or unscheduled revascularization (HR, 0.98; 95% CI, 0.64-1.49; P = .91) but was associated with the secondary end point of cardiac death or nonfatal myocardial infarction (47 of 421 patients with high plaque activity [11.2%] vs 19 of 283 with low plaque activity [6.7%]; HR, 1.82; 95% CI, 1.07-3.10; P = .03) and all-cause mortality (30 of 421 patients with high plaque activity [7.1%] vs 9 of 283 with low plaque activity [3.2%]; HR, 2.43; 95% CI, 1.15-5.12; P = .02). After adjustment for differences in baseline clinical characteristics, coronary angiography findings, and Global Registry of Acute Coronary Events score, high coronary plaque activity was associated with cardiac death or nonfatal myocardial infarction (HR, 1.76; 95% CI, 1.00-3.10; P = .05) but not with all-cause mortality (HR, 2.01; 95% CI, 0.90-4.49; P = .09). Conclusions and Relevance: In this cohort study of patients with recent myocardial infarction, coronary atherosclerotic plaque activity was not associated with the primary composite end point. The findings suggest that risk of cardiovascular death or myocardial infarction in patients with elevated plaque activity warrants further research to explore its incremental prognostic implications.


Assuntos
Doença da Artéria Coronariana , Infarto do Miocárdio , Placa Aterosclerótica , Humanos , Masculino , Feminino , Placa Aterosclerótica/complicações , Placa Aterosclerótica/diagnóstico por imagem , Estudos Prospectivos , Estudos de Coortes , Fluoreto de Sódio , Doença da Artéria Coronariana/complicações , Infarto do Miocárdio/complicações , Morte
5.
Circulation ; 143(25): 2418-2427, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-33913339

RESUMO

BACKGROUND: Valvular calcification is central to the pathogenesis and progression of aortic stenosis, with preclinical and observational studies suggesting that bone turnover and osteoblastic differentiation of valvular interstitial cells are important contributory mechanisms. We aimed to establish whether inhibition of these pathways with denosumab or alendronic acid could reduce disease progression in aortic stenosis. METHODS: In a single-center, parallel group, double-blind randomized controlled trial, patients >50 years of age with calcific aortic stenosis (peak aortic jet velocity >2.5 m/s) were randomized 2:1:2:1 to denosumab (60 mg every 6 months), placebo injection, alendronic acid (70 mg once weekly), or placebo capsule. Participants underwent serial assessments with Doppler echocardiography, computed tomography aortic valve calcium scoring, and 18F-sodium fluoride positron emission tomography and computed tomography. The primary end point was the calculated 24-month change in aortic valve calcium score. RESULTS: A total of 150 patients (mean age, 72±8 years; 21% women) with calcific aortic stenosis (peak aortic jet velocity, 3.36 m/s [2.93-3.82 m/s]; aortic valve calcium score, 1152 AU [655-2065 AU]) were randomized and received the allocated trial intervention: denosumab (n=49), alendronic acid (n=51), and placebo (injection n=25, capsule n=25; pooled for analysis). Serum C-terminal telopeptide, a measure of bone turnover, halved from baseline to 6 months with denosumab (0.23 [0.18-0.33 µg/L] to 0.11 µg/L [0.08-0.17 µg/L]) and alendronic acid (0.20 [0.14-0.28 µg/L] to 0.09 µg/L [0.08-0.13 µg/L]) but was unchanged with placebo (0.23 [0.17-0.30 µg/L] to 0.26 µg/L [0.16-0.31 µg/L]). There were no differences in 24-month change in aortic valve calcium score between denosumab and placebo (343 [198-804 AU] versus 354 AU [76-675 AU]; P=0.41) or alendronic acid and placebo (326 [138-813 AU] versus 354 AU [76-675 AU]; P=0.49). Similarly, there were no differences in change in peak aortic jet velocity or 18F-sodium fluoride aortic valve uptake. CONCLUSIONS: Neither denosumab nor alendronic acid affected progression of aortic valve calcification in patients with calcific aortic stenosis. Alternative pathways and mechanisms need to be explored to identify disease-modifying therapies for the growing population of patients with this potentially fatal condition. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02132026.


Assuntos
Alendronato/uso terapêutico , Estenose da Valva Aórtica/diagnóstico por imagem , Estenose da Valva Aórtica/tratamento farmacológico , Conservadores da Densidade Óssea/uso terapêutico , Denosumab/uso terapêutico , Progressão da Doença , Idoso , Idoso de 80 Anos ou mais , Estenose da Valva Aórtica/metabolismo , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Resultado do Tratamento , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/tratamento farmacológico , Calcificação Vascular/metabolismo
6.
Circ Cardiovasc Imaging ; 13(12): e011438, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33297761

RESUMO

Background Positron emission tomography (PET) using 18F-sodium fluoride (18F-fluoride) to detect microcalcification may provide insight into disease activity in coronary atherosclerosis. This study aimed to investigate the relationship between 18F-fluoride uptake and progression of coronary calcification in patients with clinically stable coronary artery disease. Methods Patients with established multivessel coronary atherosclerosis underwent 18F-fluoride PET-computed tomography angiography and computed tomography calcium scoring, with repeat computed tomography angiography and calcium scoring at one year. Coronary PET uptake was analyzed qualitatively and semiquantitatively in diseased vessels by measuring maximum tissue-to-background ratio. Coronary calcification was quantified by measuring calcium score, mass, and volume. Results In a total of 183 participants (median age 66 years, 80% male), 116 (63%) patients had increased 18F-fluoride uptake in at least one vessel. Individuals with increased 18F-fluoride uptake demonstrated more rapid progression of calcification compared with those without uptake (change in calcium score, 97 [39-166] versus 35 [7-93] AU; P<0.0001). Indeed, the calcium score only increased in coronary segments with 18F-fluoride uptake (from 95 [30-209] to 148 [61-289] AU; P<0.001) and remained unchanged in segments without 18F-fluoride uptake (from 46 [16-113] to 49 [20-115] AU; P=0.329). Baseline coronary 18F-fluoride maximum tissue-to-background ratio correlated with 1-year change in calcium score, calcium volume, and calcium mass (Spearman ρ=0.37, 0.38, and 0.46, respectively; P<0.0001 for all). At the segmental level, baseline 18F-fluoride activity was an independent predictor of calcium score at 12 months (P<0.001). However, at the patient level, this was not independent of age, sex, and baseline calcium score (P=0.50). Conclusions Coronary 18F-fluoride uptake identifies both patients and individual coronary segments with more rapid progression of coronary calcification, providing important insights into disease activity within the coronary circulation. At the individual patient level, total calcium score remains an important marker of disease burden and progression. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02110303.


Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Radioisótopos de Flúor , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Calcificação Vascular/diagnóstico por imagem , Idoso , Angiografia por Tomografia Computadorizada , Angiografia Coronária , Doença da Artéria Coronariana/tratamento farmacológico , Progressão da Doença , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/uso terapêutico , Valor Preditivo dos Testes , Estudos Prospectivos , Escócia , Fatores de Tempo , Resultado do Tratamento , Calcificação Vascular/tratamento farmacológico
7.
J Bone Miner Res ; 35(7): 1246-1252, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32176830

RESUMO

Mutations in SQSTM1 are strongly associated with Paget's disease of bone (PDB), but little is known about the clinical characteristics of those with early disease. Radionuclide bone scans, biochemical markers of bone turnover, and clinical characteristics were analyzed in SQSTM1 mutation carriers who took part in the Zoledronic acid in the Prevention of Paget's disease (ZiPP) study. We studied 222 individuals, of whom 54.9% were female, with mean ± SE age of 50.1 ± 0.6 years. Twelve SQSTM1 mutations were observed, including p.Pro392Leu, which was present in 141 of 222 (63.5%) subjects. Bone scan examination revealed evidence of PDB in 20 subjects (9.0%), ten of whom (50%) had a single affected site. Participants with lesions were older than those without lesions but the difference was not significant (53.6 ± 9.1 versus 49.8 ± 8.9; p = .07). The mean age of participants with lesions was not significantly different from the age at which their parents were diagnosed with PDB (55 years versus 59 years, p = .17). All individuals with lesions were asymptomatic. Serum concentrations of total alkaline phosphatase (ALP) normalized to the upper limit of normal in each center were higher in those with lesions (0.75 ± 0.69 versus 0.42 ± 0.29 arbitary units; p < .0001). Similar findings were observed for other biochemical markers of bone turnover, but the sensitivity of ALP and other markers in detecting lesions was poor. Asymptomatic PDB is present in about 9% of SQSTM1 mutation carriers by the fifth decade. Further follow-up of this cohort will provide important information on the natural history of early PDB and its response to treatment. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Osteíte Deformante , Proteína Sequestossoma-1 , Proteínas Adaptadoras de Transdução de Sinal/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Osteíte Deformante/epidemiologia , Osteíte Deformante/genética , Proteína Sequestossoma-1/genética , Ácido Zoledrônico
8.
JACC Cardiovasc Imaging ; 13(7): 1549-1560, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31422134

RESUMO

OBJECTIVES: The goal of this study was to determine whether ticagrelor reduces high-sensitivity troponin I concentrations in patients with established coronary artery disease and high-risk coronary plaque. BACKGROUND: High-risk coronary atherosclerotic plaque is associated with higher plasma troponin concentrations suggesting ongoing myocardial injury that may be a target for dual antiplatelet therapy. METHODS: In a randomized, double-blind, placebo-controlled trial, patients with multivessel coronary artery disease underwent coronary 18F-fluoride positron emission tomography/coronary computed tomography scanning and measurement of high-sensitivity cardiac troponin I. Patients were randomized (1:1) to receive ticagrelor 90 mg twice daily or matched placebo. The primary endpoint was troponin I concentration at 30 days in patients with increased coronary 18F-fluoride uptake. RESULTS: In total, 202 patients were randomized to treatment, and 191 met the pre-specified criteria for inclusion in the primary analysis. In patients with increased coronary 18F-fluoride uptake (120 of 191), there was no evidence that ticagrelor had an effect on plasma troponin concentrations at 30 days (ratio of geometric means for ticagrelor vs. placebo: 1.11; 95% confidence interval: 0.90 to 1.36; p = 0.32). Over 1 year, ticagrelor had no effect on troponin concentrations in patients with increased coronary 18F-fluoride uptake (ratio of geometric means: 0.86; 95% confidence interval: 0.63 to 1.17; p = 0.33). CONCLUSIONS: Dual antiplatelet therapy with ticagrelor did not reduce plasma troponin concentrations in patients with high-risk coronary plaque, suggesting that subclinical plaque thrombosis does not contribute to ongoing myocardial injury in this setting. (Dual Antiplatelet Therapy to Reduce Myocardial Injury [DIAMOND]; NCT02110303).


Assuntos
Intervenção Coronária Percutânea , Placa Aterosclerótica , Ticagrelor/uso terapêutico , Vasos Coronários , Humanos , Masculino , Placa Aterosclerótica/tratamento farmacológico , Inibidores da Agregação Plaquetária , Valor Preditivo dos Testes , Estudos Prospectivos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
9.
BMJ Open ; 9(9): e030689, 2019 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-31488492

RESUMO

INTRODUCTION: Paget's disease of bone (PDB) is characterised by increased and disorganised bone remodelling affecting one or more skeletal sites. Complications include bone pain, deformity, deafness and pathological fractures. Mutations in sequestosome-1 (SQSTM1) are strongly associated with the development of PDB. Bisphosphonate therapy can improve bone pain in PDB, but there is no evidence that treatment alters the natural history of PDB or prevents complications. The Zoledronate in the Prevention of Paget's disease trial (ZiPP) will determine if prophylactic therapy with the bisphosphonate zoledronic acid (ZA) can delay or prevent the development of PDB in people who carry SQSTM1 mutations. METHODS AND ANALYSIS: People with a family history of PDB aged >30 years who test positive for SQSTM1 mutations are eligible to take part. At the baseline visit, participants will be screened for the presence of bone lesions by radionuclide bone scan. Biochemical markers of bone turnover will be measured and questionnaires completed to assess pain, health-related quality of life (HRQoL), anxiety and depression. Participants will be randomised to receive a single intravenous infusion of 5 mg ZA or placebo and followed up annually for between 4 and 8 years at which point baseline assessments will be repeated. The primary endpoint will be new bone lesions assessed by radionuclide bone scan. Secondary endpoints will include changes in biochemical markers of bone turnover, pain, HRQoL, anxiety, depression and PDB-related skeletal events. ETHICS AND DISSEMINATION: The study was approved by the Fife and Forth Valley Research Ethics Committee on 22 December 2008 (08/S0501/84). Following completion of the trial, a manuscript will be submitted to a peer-reviewed journal. The results of this trial will inform clinical practice by determining if early intervention with ZA in presymptomatic individuals with SQSTM1 mutations can prevent or slow the development of bone lesions with an adverse event profile that is acceptable. TRIAL REGISTRATION NUMBER: ISRCTN11616770.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Osteíte Deformante/genética , Osteíte Deformante/prevenção & controle , Proteína Sequestossoma-1/genética , Ácido Zoledrônico/uso terapêutico , Adulto , Ansiedade/etiologia , Depressão/etiologia , Testes Genéticos , Humanos , Dor Musculoesquelética/etiologia , Mutação , Osteíte Deformante/complicações , Osteíte Deformante/diagnóstico por imagem , Qualidade de Vida , Cintilografia , Ensaios Clínicos Controlados Aleatórios como Assunto
10.
Circ Cardiovasc Imaging ; 12(8): e008574, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31382765

RESUMO

BACKGROUND: Coronary 18F-fluoride positron emission tomography identifies ruptured and high-risk atherosclerotic plaque. The optimal method to identify, to quantify, and to categorize increased coronary 18F-fluoride uptake and determine its reproducibility has yet to be established. This study aimed to optimize the identification, quantification, categorization, and scan-rescan reproducibility of increased 18F-fluoride activity in coronary atherosclerotic plaque. METHODS: In a prospective observational study, patients with multi-vessel coronary artery disease underwent serial 18F-fluoride positron emission tomography. Coronary 18F-fluoride activity was visually assessed, quantified, and categorized with reference to maximal tissue to background ratios. Levels of agreement for both visual and quantitative methods were determined between scans and observers. RESULTS: Thirty patients (90% male, 20 patients with stable coronary artery disease, and 10 with recent type 1 myocardial infarction) underwent paired serial positron emission tomography-coronary computed tomography angiography imaging within an interval of 12±5 days. A mean of 3.7±1.8 18F-fluoride positive plaques per patient was identified after recent acute coronary syndrome, compared with 2.4±2.3 positive plaques per patient in stable coronary artery disease. The bias in agreement in maximum tissue to background ratio measurements in visually positive plaques was low between observers (mean difference, -0.01; 95% limits of agreement, -0.32 to 0.30) or between scans (mean difference, 0.06; 95% limits of agreement, -0.49 to 0.61). Good agreement in the categorization of focal 18F-fluoride uptake was achieved using visual assessment alone (κ=0.66) and further improved at higher maximum tissue to background ratio values. CONCLUSIONS: Coronary 18F-fluoride activity is a precise and reproducible metric in the coronary vasculature. The analytical performance of 18F-fluoride is sufficient to assess the prognostic utility of this radiotracer as a noninvasive imaging biomarker of plaque vulnerability. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT02110303 and NCT02278211.


Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Radioisótopos de Flúor , Placa Aterosclerótica/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Idoso , Vasos Coronários/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes
11.
Circ Cardiovasc Imaging ; 9(10)2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27733431

RESUMO

BACKGROUND: 18F-Fluoride positron emission tomography (PET) and computed tomography (CT) can measure disease activity and progression in aortic stenosis. Our objectives were to optimize the methodology, analysis, and scan-rescan reproducibility of aortic valve 18F-fluoride PET-CT imaging. METHODS AND RESULTS: Fifteen patients with aortic stenosis underwent repeated 18F-fluoride PET-CT. We compared nongated PET and noncontrast CT, with a modified approach that incorporated contrast CT and ECG-gated PET. We explored a range of image analysis techniques, including estimation of blood-pool activity at differing vascular sites and a most diseased segment approach. Contrast-enhanced ECG-gated PET-CT permitted localization of 18F-fluoride uptake to individual valve leaflets. Uptake was most commonly observed at sites of maximal mechanical stress: the leaflet tips and the commissures. Scan-rescan reproducibility was markedly improved using enhanced analysis techniques leading to a reduction in percentage error from ±63% to ±10% (tissue to background ratio MDS mean of 1.55, bias -0.05, limits of agreement -0·20 to +0·11). CONCLUSIONS: Optimized 18F-fluoride PET-CT allows reproducible localization of calcification activity to different regions of the aortic valve leaflet and commonly to areas of increased mechanical stress. This technique holds major promise in improving our understanding of the pathophysiology of aortic stenosis and as a biomarker end point in clinical trials of novel therapies. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02132026.


Assuntos
Estenose da Valva Aórtica/diagnóstico por imagem , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/patologia , Calcinose/diagnóstico por imagem , Fluordesoxiglucose F18/administração & dosagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Valva Aórtica/fisiopatologia , Estenose da Valva Aórtica/fisiopatologia , Calcinose/fisiopatologia , Técnicas de Imagem de Sincronização Cardíaca , Meios de Contraste/administração & dosagem , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Reprodutibilidade dos Testes , Escócia , Índice de Gravidade de Doença
12.
Mol Genet Metab ; 103(3): 254-61, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21474354

RESUMO

G6PC3 is a widely expressed isoform of glucose-6-phosphatase, found in many foetal and adult tissues. Mutations in this gene cause developmental abnormalities and severe neutropenia due to abolition of glucose recycling between the cytoplasm and endoplasmic reticulum. Low G6PC3 expression as a result of promoter polymorphisms or dysregulation could produce similar outcomes. Here we investigated the regulation of human G6PC3 promoter activity. HeLa and H4IIE cells were transiently transfected with G6PC3 promoter coupled to the firefly luciferase gene, and promoter activity was measured by dual luciferase assay. Activity was highest in a 453 bp segment of the G6PC3 promoter, from -455 to -3 relative to the transcriptional start site. This promoter was unresponsive to glucostatic hormones. Its activity increased significantly between 1 and 5.5 mM glucose, and was not elevated further by glucose concentrations up to 25 mM. Pyruvate increased its activity, but ß-hydroxybutyrate and sodium acetate did not. Promoter activity was reduced by inhibitors of hexokinase, glyceraldehyde phosphate dehydrogenase and the oxidative branch of the pentose phosphate pathway, but not by a transketolase inhibitor. Deletion of two adjacent Enhancer-boxes (-274 to -279 and -299 to -304) reduced promoter activity and abolished the glucose effect, suggesting they could function as a glucose response element. Deletion of an additional downstream 140 bp (-140 to -306) restored activity, but not the glucose response, suggesting the presence of repressor elements in this region. 5-Aminoimidazole-4-carboxamide 1-ß-D-ribofuranoside (AICAR) reduced promoter activity, showing dependence on AMP-kinase. Regulation of the G6PC3 promoter is thus radically different to that of the hepatic isoform, G6PC. It is sensitive to carbohydrate, but not to fatty acid metabolites, and at much lower physiological concentrations. Based on these findings, we speculate that reduced G6PC3 expression could occur during hypoglycemic episodes in vivo, which are common in utero and in the postnatal period. If such episodes lower G6PC3 expression they could place the foetus or infant at risk of impaired immune function and development, and this possibility requires further examination both in vitro and in vivo.


Assuntos
Região 5'-Flanqueadora , Adenilato Quinase/metabolismo , Glucose-6-Fosfatase , Glucose/farmacologia , Via de Pentose Fosfato/fisiologia , Regiões Promotoras Genéticas , Ácido Pirúvico/farmacologia , Região 5'-Flanqueadora/genética , Sequência de Bases , Sítios de Ligação/genética , Linhagem Celular , Sequência Consenso/genética , Inibidores Enzimáticos/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Ordem dos Genes , Glucose/metabolismo , Glucose-6-Fosfatase/genética , Glucose-6-Fosfatase/metabolismo , Células HeLa , Hormônios/farmacologia , Humanos , Dados de Sequência Molecular , Regiões Promotoras Genéticas/genética , Ácido Pirúvico/metabolismo , Fatores de Transcrição/metabolismo , Sítio de Iniciação de Transcrição
13.
Br Dent J ; 201(12): 790-1, 2006 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-17183410

RESUMO

Partly as a consequence of the inquiries into the events at the Bristol Royal Infirmary and the Royal Liverpool Children's Hospital (Alder Hey), the Government recently enacted the Human Tissue Act 2004. The main provisions of the Act came into force on 1 September 2006 and have potential implications for dentists.


Assuntos
Legislação Odontológica , Obtenção de Tecidos e Órgãos/legislação & jurisprudência , Transplante/legislação & jurisprudência , Humanos , Consentimento Livre e Esclarecido/legislação & jurisprudência , Dente/transplante , Reino Unido
14.
J Mol Med (Berl) ; 83(8): 610-8, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15918042

RESUMO

Sudden and unexpected infant deaths can be unexplained [sudden infant death syndrome (SIDS)] or explained (non-SIDS) but risk factors including lower birthweight are similar in both groups. Mutations in the glucokinase (GK) gene result in Maturity Onset Diabetes of the Young type 2 (MODY 2) and are associated with lower birthweight. Low hepatic glucose-6-phosphatase (G6PC1) expression occurs in both low birthweight and SIDS infants. We investigated whether polymorphisms are prevalent in the GK and G6PC1 genes in infants who died suddenly and unexpectedly. Mutation analysis was performed by polymerase chain reaction (PCR) and denaturing high-performance liquid chromatography (DHPLC) in samples from 126 infants who died suddenly and unexpectedly (78 SIDS, 48 non-SIDS) and from 70 healthy, living infants. G6PC1 promoter polymorphism significance was investigated by transfection of reporter gene constructs into a H4IIE cell line. Heterozygous GK polymorphisms were identified in 17.9% of SIDS and 20.8% of non-SIDS infants: two rare silent polymorphisms, Y215Y and S263S, in the coding region; a third rare polymorphism, -45G>A, in the hepatic promoter and the most prevalent polymorphism, c.484-29G>C, in a non-coding region upstream from the intron 4-exon 5 junction. A novel heterozygous polymorphism -77G>A in the G6PC1 promoter in 6.3% of non-SIDS and 2.9% of control infants decreased basal G6PC1 promoter activity (p<0.001). We describe three novel polymorphisms in the GK gene, S263S, -45G>A, and a common (14.3%) intronic substitution, c.484-29G>C, in infants who died suddenly and unexpectedly. We identified the first G6PC1 promoter polymorphism, which lowers expression, potentially increasing risk of hypoglycaemia and hence risk of sudden and unexpected death.


Assuntos
Glucoquinase/genética , Glucose-6-Fosfatase/genética , Polimorfismo Genético , Morte Súbita do Lactente/genética , Animais , Feminino , Humanos , Lactente , Masculino , Mutação , Ratos
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