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1.
J Bone Miner Res ; 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32176830

RESUMO

OBJECTIVES: 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. METHODS: Radionuclide bone scans, biochemical markers of bone turnover and clinical characteristics were analysed in SQSTM1 mutation carriers who took part in the Zoledronic acid in the Prevention of Paget's disease (ZiPP) study. RESULTS: We studied 222 individuals of whom 54.9% were female with average (± sem) age of 50.1± 0.6 years. Twelve SQSTM1 mutations were observed, including p.Pro392Leu which was present in 141/222 (63.5%) subjects. Bone scan examination revealed evidence of PDB in 20 subjects (9.0%) of which 9 (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 vs. 49.8 ± 8.9, p=0.07). The mean age of participants with lesions was not significantly different from the age at which their parents were diagnosed with PDB (55 years vs. 59 years, p=0.25). All individuals with lesions were asymptomatic. Serum concentrations of total alkaline phosphatase (ALP) normalised to the upper limit of normal in each centre were higher in those with lesions (0.75 ± 0.69 vs 0.42 ± 0.29; p<0.0001). Similar findings were observed for other biochemical markers of bone turnover but the sensitivity of ALP and other markers in detecting lesions was poor. CONCLUSIONS: 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. This article is protected by copyright. All rights reserved.

2.
BMJ Open ; 9(9): e030689, 2019 Sep 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.

3.
Circ Cardiovasc Imaging ; 12(8): e008574, 2019 Aug.
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.

4.
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).

5.
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 Computadorizada com Tomografia por Emissão de Pósitrons , 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
6.
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
7.
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
8.
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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