197 results on '"Denvir, Martin A."'
Search Results
152. Untitled.
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Denvir, Martin A., Haga, Kristin, and Murray, Scott
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LETTERS to the editor , *HEART failure patients - Abstract
A response by authors to a letter to the editor about their article Identifying community based chronic heart failure patients in the last year of life: A comparison of the Gold Standards Framework Prognostic Indicator Guide and the Seattle Heart Failure Model" in the August 21, 2012 issue is presented.
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- 2012
153. Cardiomyocyte cell-cell junctions in development, disease and injury
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Maqsood, Sana Abrar, Denvir, Martin, and Gray, Gillian
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616.1 ,cardiomyocytes ,arrhythmogenic right ventricular cardiomyopathy ,ARVC ,zebrafish ,Naxos disease ,cell-cell junction proteins ,GSK-3 inhibitor - Abstract
Introduction: Cardiac cell-cell junctions play important roles in maintaining cardiac integrity linking single cardiomyocytes into a single functioning syncytium. There are three main types of cell junctions in the heart: gap junctions (GJ), desmosomes (D) and adherens junctions (AJ). Mutations in the proteins which make-up these junctions are known to cause arrhythmogenic right ventricular cardiomyopathy (ARVC). Pathological features include progressive replacement of right ventricular cardiac muscle with fibrofatty tissue. This can lead to heart failure and life threatening arrhythmias. During normal development of the mammalian heart, protein components of AJ and D gradually fuse to form composite junctions at the intercalated discs, also called areae compositae (singular, area composita, AC). In contrast, the adult heart of lower vertebrates, including the zebrafish, may have few or no AC type junctions. The detailed structure of cardiomyocyte cell-cell junctions in the adult zebrafish heart remain poorly defined and their role in normal development, growth and response to injury have yet to be studied. This thesis will examine the hypothesis that localisation and distribution of myocardial cell-cell junction proteins are crucial in normal myocardial development and in endogenous cardiac regeneration and repair following injury. This will be achieved by understanding the normal development of cell-cell junction proteins in zebrafish from embryonic to adulthood. These findings will then be analysed in comparison to cell-cell junction proteins localisation and distribution in early and late mammalian (mouse and human) myocardium. Once a normal pattern of cell-cell junction proteins will be established, the localisation of cell-cell junction proteins in plakologbin mutant zebrafish model for cardiomyopathy will be studied to understand the distribution and localisation of these proteins in disease manifestation. This model will then be used to test if localisation of cell-cell junction proteins plays an important in cardiac repair following injury by using embryonic laser injury model, this will be further tested by drug intervention study to investigate underlying pathways such as Wnt signalling pathway. Methods: Myocardial cell-cell junctions were assessed using immunohistochemistry in embryonic, juvenile and adult zebrafish hearts and in foetal and adult human hearts. The Plakoglobin mutant zebrafish line (UAS:Gal-4:Plakoglobin Naxos; named as PGNx) was characterised using various functional and morphological assessments including histology, echocardiography and MRI scanning. Similar studies were undertaken in PGNx mutants at different developmental stages. A pharmacological intervention study, using a GSK-3 inhibitor, was carried out in PGNx mutants followed by cardiac structural and functional assessments. Laser-induced cardiac trauma was used to assess the response to injury and repair in normal and PGNx embryos following treatment with the GSK3 inhibitor drug. Results: Cell-cell junction patterning in the embryonic, juvenile and adult zebrafish heart shows a characteristic pearl string appearance of desmoplakin and β-catenin labelled distinct disc shaped AJ. Human foetal heart showed small distinct D and AJ, while the adult human heart had features consistent with AC type junctions. PGNx fish showed reduced ventricle ejection fraction, dilatation of the atrium, reduced amplitude of wall motion and ventricle relaxation velocity compared to age-matched controls. Echocardiography and MRI imaging confirmed severe atrial dilatation and restrictive ventricle physiology in adult fish. The cell-cell junction proteins were over-expressed in the zebrafish PG mutant (PGNx) hearts compared to age-matched controls. Drug studies using a GSK-3β inhibitor showed complete recovery of cardiac function and partial recovery of heart structure. Cardiac injury studies, using laser, showed failure of repair in PGNx embryos compared to age-matched controls. The GSK3 inhibitor failed to improve the functional response following heart laser injury. Conclusions: Cell-cell junctions are distributed abundantly around cardiomyocytes in the zebrafish heart during early development and into adulthood. In contrast to previous studies in adult mammalian heart, there was no evidence of AC type junctions in adult zebrafish cardiomyocytes. The mutant zebrafish line showed restrictive cardiac physiology and abnormal cardiac structure confirming the key role played by plakoglobin in the normal heart development. This is further supported by evidence showing failure of repair in PGNx mutant embryos after injury. Drug treatment with a GSK-3 inhibitor highlights a potentially novel therapeutic pathway for treatment of ARVC involving Wnt signalling.
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- 2017
154. Glucocorticoids and foetal heart maturation; implications for prematurity and foetal programming.
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Rog-Zielinska, Eva A., Richardson, Rachel V., Denvir, Martin A., and Chapman, Karen E.
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FETAL heart , *HEART development , *GLUCOCORTICOIDS , *PREMATURE labor , *NEONATOLOGY , *PREGNANCY complications , *PHYSIOLOGY - Abstract
Glucocorticoids are steroid hormones, essential in mammals to prepare for life after birth. Blood levels of glucocorticoids (cortisol in most mammals including humans; corticosterone in rats and mice) rise dramatically shortly before birth. This is mimicked clinically in the routine administration of synthetic glucocorticoids to pregnant women threatened by a preterm birth or to preterm infants to improve neonatal survival. Whilst effects on lung are well documented and essential for postnatal survival, those on heart are less well known. In this study, we review recent evidence for a crucial role of glucocorticoids in late gestational heart maturation. Either insufficient or excessive glucocorticoid exposure before birth may alter the normal glucocorticoid-regulated trajectory of heart maturation with potential life-long consequences. [ABSTRACT FROM AUTHOR]
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- 2014
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155. Development of catheter techniques to treat native and acquired stenoses in congenital heart disease
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Magee, Alan Gordon and Denvir, Martin
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616.1 ,cardiac catheter ,congenital heart disease ,balloon angioplasty ,stent implantation - Abstract
Aim: To describe innovative uses of catheter based treatment in a variety of native and post surgical stenoses in children and young adults with congenital heart disease. Background: Cardiac catheterization in man was first described 1929 and since then there has been a drive to develop endovascular techniques to investigate and treat both congenital and acquired heart disease. Many of the advances are being made in congenital heart disease. Methods: A number of congenital cardiac stenotic lesions were studied including baffle obstruction after atrial switch for transposition of the great arteries, aortic stenosis in infants, coarctation of the aorta, peripheral pulmonary artery stenosis and superior vena caval obstruction. The use of angioplasty balloons, cutting balloons, stents and alternative catheter approaches were investigated for these lesions. Results: Following atrial redirection surgery for transposition of the great arteries balloon angioplasty improved baffle haemodynamics. The technique of anterograde balloon dilation of the aortic valve was developed and had superior outcomes in terms of aortic insufficiency compared to a retrograde approach in neonates with severe aortic valve stenosis. In an animal model of peripheral pulmonary arterial stenosis, the application of cutting balloon angioplasty produced effective relief in a controlled fashion. Balloon mounted stents were used in patients with native and post surgical coarctation of the aorta with significant relief of stenosis and relief of hypertension. Finally, a group of patients with superior vena obstruction syndrome after surgical repair of partial anomalous pulmonary venous drainage had successful treatment using balloon mounted stents. Conclusions: Catheter based treatment of congenital and post surgical vascular stenoses of the heart and great arteries using angioplasty balloons, cutting balloons and balloon mounted stents is safe and appears to be effective in the short and medium term. It may represent a useful alternative to surgery and will reduce the number of surgical procedures required over a lifetime. Future directions will include bio-absorbable stents and hybrid techniques involving surgery.
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- 2016
156. Valvular heart disease : novel epidemiological and imaging studies
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d'Arcy, Joanna Louise, Denvir, Martin, Prendergast, Bernard, and Myerson, Saul
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616.1 ,valvular heart disease ,VHD ,mitral regurgitation ,cardiac magnetic resonance - Abstract
Since living conditions have improved and antibiotics have entered routine use, valvular heart disease (VHD) in the developed world is mostly degenerative in origin, rather than rheumatic. Our population is increasing with age, and therefore the burden of VHD is likely to increase. Despite this, the epidemiology & prognostication in VHD remain poorly understood. A better understanding of the prevalence of VHD in our population, and improved methods of predicting outcomes, are essential if we are to be better equipped to meet the challenges of this new “epidemic”. This thesis aims to improve our knowledge of the prevalence of VHD in the elderly, and the potential benefits of cardiac magnetic resonance (CMR) assessment of patients with clinically significant mitral regurgitation. The prevalence of undiagnosed valvular heart disease in those aged 65 and over is examined in Chapters 2 and 3. Chapter 2 outlines a population-based screening study for VHD in primary care in Oxfordshire, which the author played a central role in establishing. The results show that VHD is extremely common in this cohort, and is strongly associated with increasing age. In chapter 4, the level of anxiety provoked by screening for VHD is looked at; this demonstrates that only a small number of patients have significant anxiety levels, but it is more likely in those with a new diagnosis of VHD, and in women. From Chapter 5 onwards, the thesis focuses on the use of CMR in patients with significant mitral regurgitation (MR). In Chapter 5, the clinical value of quantitative assessment of MR using CMR is examined, showing that it was able to predict progression to symptoms or surgery in these patients. In conclusion, this thesis offers insights into the prevalence of VHD in the elderly population, and looks at the anxiety associated with looking for VHD in this group. The potential clinical benefits of CMR in patients with MR are examined, and quantification of MR with this modality would appear to be of prognostic utility.
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- 2016
157. Validation of laser Doppler flowmetry coupled with intra-dermal injection for investigating effects of vasoactive agents on the skin microcirculation in man.
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Leslie, Stephen J., Affolter, Jonathan, Denvir, Martin A., and Webb, David J.
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INTRADERMAL injections , *MICROCIRCULATION , *CARDIOVASCULAR agents , *LASER Doppler blood flowmetry , *BLOOD circulation , *MEDICAL research - Abstract
Objective. To determine the reproducibility of laser Doppler flowmetry coupled with intra-dermal saline delivery. Methods. Delivery of saline was judged visually by two operators (n=100), using a graduated syringe (Becton-Dickinson), by expelling saline onto a weighing boat. Volume was assessed by weight. Skin blood flow following intra-dermal injection of saline was assessed in 18 healthy volunteers; 10 attended twice to assess between-day reproducibility, and 8 attended once to assess between-site reproducibility. Results are expressed as mean value±SEM and 95% confidence interval for mean differences. Results. There was no difference between operators in mean injection weight, both weights being 10.3±0.1 mg (mean difference 0.08, 95% confidence interval, CI -0.23 to 0.39 mg; n=100, P=0.9). Intra-dermal saline caused a nine-fold increase in blood flow (0.03±0.003 to 0.27±0.02 perfusion units, PU; n=18, P<0.001). This response had a rapid onset, with the maximal effect seen at 4 min and a duration of greater than 30 min. There was no difference in the magnitude of the response between the dominant and non-dominant arms, AUC was 2.9±0.4 and 2.9±0.4, respectively (mean difference -0.05, 95% CI -0.8 to 0.73 PU; n=18, P=0.93). However, there was a trend towards differences between study visits 1 and 2: AUC was 3.2±0.6 and 2.0±0.5, respectively (mean difference 1.2, 95% CI -0.03 to 2.43 PU; n=10, P=0.7). There was no difference in the magnitude of responses between different sites on the forearm (n=64, P=0.6). Conclusions. These studies demonstrate that the technique of laser Doppler flowmetry coupled with intra-dermal injection is a safe, well-tolerated technique with good reproducibility. A trend towards reduced between-day reproducibility emphasizes the importance of vehicle control sites when investigating the effects of vasoactive compounds. This technique provides a reliable method for the intra-dermal delivery of drugs, despite the direct effect of injection of saline on blood flow. [ABSTRACT FROM AUTHOR]
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- 2003
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158. Predicting readmission and death after hospital discharge: a comparison of conventional frailty measurement with an electronic health record-based score.
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Tew, Yong Yong, Chan, Juen Hao, Keeling, Polly, Shenkin, Susan D, MacLullich, Alasdair, Mills, Nicholas L, Denvir, Martin A, and Anand, Atul
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FRAIL elderly , *SCIENTIFIC observation , *CONFIDENCE intervals , *PATIENT readmissions , *HEALTH outcome assessment , *RISK assessment , *COMPARATIVE studies , *QUESTIONNAIRES , *DESCRIPTIVE statistics , *DEATH , *ELECTRONIC health records , *COMORBIDITY , *DISCHARGE planning - Abstract
Background frailty measurement may identify patients at risk of decline after hospital discharge, but many measures require specialist review and/or additional testing. Objective to compare validated frailty tools with routine electronic health record (EHR) data at hospital discharge, for associations with readmission or death. Design observational cohort study. Setting hospital ward. Subjects consented cardiology inpatients ≥70 years old within 24 hours of discharge. Methods patients underwent Fried, Short Physical Performance Battery (SPPB), PRISMA-7 and Clinical Frailty Scale (CFS) assessments. An EHR risk score was derived from the proportion of 31 possible frailty markers present. Electronic follow-up was completed for a primary outcome of 90-day readmission or death. Secondary outcomes were mortality and days alive at home ('home time') at 12 months. Results in total, 186 patients were included (79 ± 6 years old, 64% males). The primary outcome occurred in 55 (30%) patients. Fried (hazard ratio [HR] 1.47 per standard deviation [SD] increase, 95% confidence interval [CI] 1.18–1.81, P < 0.001), CFS (HR 1.24 per SD increase, 95% CI 1.01–1.51, P = 0.04) and EHR risk scores (HR 1.35 per SD increase, 95% CI 1.02–1.78, P = 0.04) were independently associated with the primary outcome after adjustment for age, sex and co-morbidity, but the SPPB and PRISMA-7 were not. The EHR risk score was independently associated with mortality and home time at 12 months. Conclusions frailty measurement at hospital discharge identifies patients at risk of poorer outcomes. An EHR-based risk score appeared equivalent to validated frailty tools and may be automated to screen patients at scale, but this requires further validation. [ABSTRACT FROM AUTHOR]
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- 2021
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159. Role of glucocorticoids in development and growth of the cardiovascular system in the zebrafish
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Wilson, Kathryn Sarah, Denvir, Martin, and Hadoke, Patrick
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597 ,zebrafish ,glucocorticoids ,early life programming - Abstract
Introduction Glucocorticoids (GCs) are synthesised endogenously in mammals by the hypothalamic pituitary adrenal (HPA) axis in response to stress. These hormones can elicit a number of physiological roles by binding to and activating specific receptors (glucocorticoid or mineralocorticoid receptors- GR or MR). GCs are important in tissue development and maturation and commonly used therapeutically. Mammalian animal studies have suggested that over-exposure to GCs, whether pharmacologically or through induction of maternal stress, is associated with increased cardiovascular disease risk in adult life. The underlying mechanisms underpinning this early life programming are poorly understood, however GC exposure during development may have direct and indirect effects on the structure and function of developing tissues and organs which may predispose to disease in later life. Current mammalian models of programming do not lend themselves well to studying organ development during embryogenesis. The zebrafish provides an ideal model to study this phenomenon due to the transparent nature of developing larvae and the availability of transgenic lines expressing fluorescent markers. Methods GC pathways were comprehensively characterised during zebrafish embryo development using qRT-PCR and steroid ELISAs. The physiological roles of GCs were assessed during early zebrafish development (first 120 hours post fertilisation (hpf)) assessing stress response, swim activity and global development following various genetic and pharmacological manipulations of the GC system. The impact that GC manipulation had on the cardiovascular system was also investigated. Embryos which had been exposed to GC manipulation during early development were then allowed to develop to adulthood in order to assess the long term impact. The same parameters were investigated in the adult as in the embryo. Results The key components of the GC system are present and functional in the developing embryo with de novo cortisol biosynthesis evident from 48hpf. A functioning hypothalamic pituitary inter-renal (HPI) axis is demonstrable from 72hpf. Manipulation of specific components of the GC pathway during early embryonic development influences growth-rate, head-trunk angle, chorion hatch-rate and swim behaviour. Manipulation of GCs during embryogenesis resulted in altered body weight, length and girth in adulthood, with altered stress response and swim behaviour also detected. Embryonic heart development was also affected with a reduction in ventricle cardiomyocyte number, cardiac gene abundance (vhmc) and cardiac function during embryogenesis resulting in structural abnormalities such as fewer trabeculae and increased intra-ventricular space. Embryonic GC manipulation also alters the formation and patterning of intersegmental blood vessels by 120hpf. In adulthood this manifests as a reduced angiogenic capacity. Conclusion The zebrafish embryo represents a valid and physiologically relevant model for GC research. Manipulation of GCs during early development results in altered growth, gene abundance and cardiovascular structure. These findings have significant implications for on-going research addressing GC mediated programming and suggest that the zebrafish is a highly suitable model for GC research.
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- 2014
160. Role of cyclin-dependent Kinase 9 in the zebrafish embryonic heart
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Matrone, Gianfranco, Denvir, Martin, and Tucker, Carl
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616.1 ,zebrafish ,heart ,cyclin-dependent kinase ,cardiac hypertrophy - Abstract
Cardiac hypertrophy leading to heart failure remains a leading cause of morbidity and mortality in the 21st century despite major therapeutic advances. Improved understanding of novel molecular and cellular processes contributing to cardiac hypertrophy therefore continues to be important. Cyclin-dependent Kinase 9 (CDK9), part of a family of proteins controlling cell cycle and growth, has emerged as one such potential candidate over the last 5 years. CDK9 is the catalytic subunit of the CDK9/CyclinT complex and acts by phosphorylating the carboxy-terminal domain of RNA polymerase II. Hypertrophic signals, such as Endothelin-1 (ET-1) and phenylephrine, have been shown to cause CDK9 activation leading to a hypertrophic response in cultured mouse cardiomyocytes associated with reactivation of the foetal gene program. CDK9 also forms a complex with GATA4 to play a role in differentiation of mouse ES cells into cardiomyocytes. These findings suggest a specific role for CDK9 in controlling growth and differentiation of cardiomyocytes and merits further study in models where cardiomyocyte differentiation and proliferation are key contributors. In contrast to mammals, zebrafish retain a high cardiomyocyte proliferative capacity throughout their life span and can readily repair following injury. I have examined the role of CDK9 on global and cardiac development in the zebrafish embryo. I have also assessed the impact of CDK9 manipulation on response to ventricle injury using a laser-induced injury model developed and validated as part of my thesis. My findings confirm that normal growth of the embryonic ventricle is associated with a rapid increase in cardiomyocyte number, that was of 50% in the period 96-120 hpf, accompanied by increasing chamber trabeculation. This is also characterized by an increase in the gene expression of most of cardiac development relevant transcription factors, i.e. GATA4, 5 and 6, and MEF2c. The significant reduced cardiovascular function (14% of Ejection Fraction compared to 20% in controls) at 2 h post laser injury in the zebrafish embryonic heart promptly recovers at 24 hour post-laser, accompanied by acceleration of cardiomyocyte proliferation, that increased of 49% in injured ventricles compared to 20% in controls in the period 2-24 h post-laser. Pharmacological and genetic inhibition of CDK9 activity also significantly reduced cardiac growth, cardiomyocyte number, ventricle function and impairs functional recovery following laser injury. Conversely, genetic inhibition of LARP7, a CDK9 repressor, resulted in increased cardiomyocyte number and was associated with full functional and cellular recovery following laser-injury. In conclusion, I have provided evidence, in the zebrafish embryonic heart, that CDK9 plays an important role in cardiac growth and development and impacts significantly on cardiomyocyte proliferation. I have also shown that CDK9 manipulation significantly affects cellular and functional recovery following laser-induced injury. Further studies are required to further define the role of CDK9 and LARP7 in the heart and develop therapeutic strategies using this pathway that could contribute to cellular repair mechanisms in the adult mammalian heart.
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- 2013
161. Characterisation and functional analysis of a novel MSP domain-containing protein, MOSPD1
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Kara, Madina, Forrester, Lesley., and Denvir, Martin
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572.6 ,MOSPD1 ,proteins ,genetic redundancy ,MOSPD3 - Abstract
MOSPD1 belongs to a class of proteins that have a major sperm protein (MSP) domain at the N terminus and two transmembrane domains at the C terminus and are thought to act as membrane adaptor proteins. Previous work in the laboratory indicated that the closely related, mammalian-specific, Mospd 3 plays a role in the development and function of the heart as homozygous Mospd 3 gene trap neonates displayed a right ventricle defect characterised by a thinning of the right ventricle wall. The function of Mospd 1 is not known. Whilst Mospd 3 is mammalian specific Mospd 1 is conserved in all vertebrates including Danio rerio (zebrafish). The aims of this thesis were to investigate the possibility of genetic redundancy between Mospd 1 and Mospd 3 by identifying the sub-cellular localisation of MOSPD1 and MOSPD3 in both cells and tissues and to investigate the function of MOSPD1. Mouse monoclonal antibodies specific for MOSPD1 and MOSPD3 were generated and tested to ensure they did not cross react. MOSPD1 was found to be localised to the nucleus whilst MOSPD3 was located in the nucleus and cytoplasm. The sub-cellular localisation of these proteins changes during the cell cycle as they were localised to the cytoplasm during cell division, possible due to the breakdown of the nuclear membrane during cell division. To investigate the function of Mospd 1 during early development Mospd 1 gene expression was knocked down using morpholino anti-sense knockdown technology. A morpholino was generated against the splice-site between exons 2 and 3 of the zebrafish Mospd 1 gene and injected into early embryos. At doses that significantly reduced the level of Mospd 1, to below 50 %, the embryos developed normally and did not exhibit any gross morphological phenotypes when compared to both noninjected and 5 mispair control morpholino-injected embryos. A morpholino targeted to the start site of the Mospd 1 gene confirmed the lack of a gross morphological phenotype. In conjunction with the zebrafish functional tests the tools were generated to assess the role of Mospd 1 in a mammalian system. A conditional allele of Mospd 1 was generated in mouse embryonic stem (ES) cells which could be used to generate a conditional Mospd 1 mouse. The electroporation of a Cre recombinase plasmid into the conditional Mospd 1 ES cell line resulted in the generation of Mospd 1 null ES clones which could be used for functional studies both in vitro and in vivo. The Mospd 1 null ES cells were able to self-renew, expressed ES cell specific markers and were able to differentiate into cardiomyocytes. However, Mospd 1 null cells showed a reduced ability to differentiate into osteoblasts compared to wild type cells and showed changes in the expression of genes involved in Epithelial to mesenchymal transition (EMT) indicating Mospd 1 may be involved in this process.
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- 2012
162. Investigation of the cardiovascular effects of apelin
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Hamilton-Smith, Katherine Mary, Smith, Katherine Mary Hamilton., Denvir, Martin., and Newby, David
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615.1 ,apelin ,cardiovascular ,zebrafish ,zebra fish - Abstract
Apelin was discovered in 1998 as the endogenous peptide ligand of the orphan APJ receptor. The apelin system is well conserved across vertebrate species and is reported to have cardiovascular effects including positive inotropy, vasodilation, vasoconstriction and cardioprotection during ischaemia. Recent studies in human healthy volunteers and in chronic heart failure patients have highlighted the apelin system as a potential target for drug development. However, the cellular and molecular pathways through which apelin acts remain poorly understood. This study aimed to confirm the inotropic and vasoactive actions of apelin and to further examine the proposed cardioprotective effects of apelin under ischaemic and hypoxic conditions. Cardioprotection is defined as a mechanism, for example induced by a drug, which reduces injury in response to ischaemia or hypoxia. In vivo in the anaesthetised rat, apelin was administered as a bolus dose via the cannulated jugular vein and mean arterial pressure was measured by cannulation of the carotid artery. Pyr-apelin-13 had no effect on heart rate or mean arterial pressure. Apelin-13 decreased mean arterial pressure by approximately 20 mmHg, although the effect was highly variable among animals. Apelin-16 consistently lowered heart rate, but had no effect on mean arterial pressure. In rat isolated mesenteric arteries, studied using wire myography, apelin-13 and apelin-36 had no vasodilator or vasoconstrictor effect. In rat isolated right ventricular papillary muscles and right atrial strips, no change in tension, time to peak or time to relax was observed in response to pyr-apelin-13 despite responding to standard pharmacological stimuli such as noradrenaline and increased calcium concentrations in the bathing medium. In isolated, perfused rat heart (Langendorff), infusion of apelin-16 for 15 minutes did not alter developed pressure, rate of rise or rate of fall detected by an intraventricular balloon positioned in the left ventricle throughout the infusion. As the isolated perfused hearts did not demonstrate an inotropic effect in response to apelin, no cardioprotective studies were carried out in this model. Cardioprotective studies of apelin were performed in zebrafish embryos 3 – 5 days post fertilisation (dpf). I developed a hypoxia-recovery model in which we could test the effect of pharmacological agents, including apelin, on the hypoxia-recovery response. In zebrafish embryos 3 dpf, 2h hypoxia (1% oxygen) reduced heart rate and wall motion amplitude (to approximately 90% of control) and contraction velocity and relaxation velocity (to approximately 80% of control). All parameters recovered during a subsequent 2h in normoxia. Incubation in pyr-apelin-13 for 1h prior to and throughout hypoxia did not affect the depression in heart rate observed on exposure to hypoxia. However, apelin incubation resulted in an improvement in wall motion amplitude and relaxation velocity and a significant improvement in contraction velocity after hypoxia and throughout recovery. Pyr-apelin-13 had no inotropic or chronotropic effect on baseline heart function in embryos 3 dpf or in isolated hearts from embryos. However, apelin knockdown using a morpholino targeting the exon 2/intron 2 boundary of apelin pre-mRNA resulted in a high mortality rate and a severe total body and cardiovascular phenotype, suggesting that endogenous apelin is crucial during development in zebrafish embryos. In order to test pharmacological agents more efficiently, I developed a semi-quantitative scoring method to screen a larger number of embryos in a reduced time period. Heart rate and circulation was defined as normal, reduced or absent after 2h and 4h in hypoxia and during recovery in normoxia. The abundance of apelin and HIF-1α mRNA was measured using quantitative RT-PCR. In zebrafish 5 dpf, a marked decrease in apelin mRNA expression was observed after 4h, but not 2h, hypoxia and this was not accompanied by a change in HIF-1α mRNA expression. In zebrafish 5 dpf, exogenous pyr-apelin-13 did not affect the proportion of embryos with normal heart rate and circulation at any timepoint in this model. However, desferrioxamine (iron chelator) and α-ketoglutarate (metabolite involved in aerobic respiration) significantly increased the proportion of embryos with normal heart rate and circulation during the recovery phase. In summary, apelin-13 and apelin-16 were effective in lowering mean arterial pressure and heart rate, respectively, in the anaesthetised rat. However, apelin-13 did not vasodilate or vasoconstrict rat isolated mesenteric arteries. There was no effect of apelin on contractility parameters in rat isolated papillary muscles or in the isolated, perfused rat heart which made it difficult to pursue a cardioprotective effect in this model. In zebrafish, endogenous apelin appeared to be crucial in the development of the embryo, while exogenous apelin had no inotropic effect on cardiac function. In hypoxia-recovery, we demonstrate a cardioprotective effect of apelin in zebrafish 3 dpf, but not zebrafish 5 dpf.
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- 2011
163. Patient selection for high sensitivity cardiac troponin testing and diagnosis of myocardial infarction : prospective cohort study
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Shah, Anoop S V, Sandoval, Yader, Noaman, Ala, Sexter, Anne, Vaswani, Amar, Smith, Stephen W, Gibbins, Mathew, Griffiths, Megan, Chapman, Andrew R, Strachan, Fiona E, Anand, Atul, Denvir, Martin A, Adamson, Philip D, D’Souza, Michelle S, Gray, Alasdair J, McAllister, David A, Newby, David E, Apple, Fred S, and Mills, Nicholas L
164. Rapid and recoverable in vivo magnetic resonance imaging of the adult zebrafish at 7T.
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Merrifield, Gavin D., Mullin, James, Gallagher, Lindsay, Tucker, Carl, Jansen, Maurits A., Denvir, Martin, and Holmes, William M.
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MAGNETIC resonance imaging , *LABORATORY zebrafish , *IN vivo studies , *EMBRYOLOGY , *IMAGE quality analysis - Abstract
Increasing scientific interest in the zebrafish as a model organism across a range of biomedical and biological research areas raises the need for the development of in vivo imaging tools appropriate to this subject. Development of the embryonic and early stage forms of the subject can currently be assessed using optical based techniques due to the transparent nature of the species at these early stages. However this is not an option during the juvenile and adult stages when the subjects become opaque. Magnetic resonance imaging (MRI) techniques would allow for the longitudinal and non-invasive assessment of development and health in these later life stages. However, the small size of the zebrafish and its aquatic environment represent considerable challenges for the technique. We have developed a suitable flow cell system that incorporates a dedicated MRI imaging coil to solve these challenges. The system maintains and monitors a zebrafish during a scan and allows for it to be fully recovered. The imaging properties of this system compare well with those of other preclinical MRI coils used in rodent models. This enables the rapid acquisition of MRI data which are comparable in terms of quality and acquisition time. This would allow the many unique opportunities of the zebrafish as a model organism to be combined with the benefits of non-invasive MRI. [ABSTRACT FROM AUTHOR]
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- 2017
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165. Mineralocorticoid receptor antagonists in elderly patients with heart failure: a systematic review and meta-analysis.
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JAPP, DEEPA, SHAH, ANOOP, FISKEN, SHEILA, DENVIR, MARTIN, SHENKIN, SUSAN, and JAPP, ALAN
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HEART ventricle diseases , *CINAHL database , *CONFIDENCE intervals , *LEFT heart ventricle , *HEART failure , *HORMONE antagonists , *HOSPITAL care , *MEDICAL information storage & retrieval systems , *MEDLINE , *META-analysis , *MINERALOCORTICOIDS , *PROBABILITY theory , *KIDNEY failure , *SAFETY , *SYSTEMATIC reviews , *RELATIVE medical risk , *TREATMENT effectiveness , *DATA analysis software , *HYPERKALEMIA , *DESCRIPTIVE statistics , *ODDS ratio , *OLD age - Abstract
Background: mineralocorticoid receptor antagonists (MRAs) improve outcomes in several populations of patients with heart failure (HF), but there has been no systematic review of MRAs in older patients. Objectives: systematic review and meta-analysis of the efficacy and safety of MRA treatment in elderly HF patients. Data sources: trials were identified through a literature search until 24 January 2015. Study selection: randomised controlled trials (RCTs) of MRAs in patients with HF and/or left ventricular systolic dysfunction aged ≥65 years, with subgroup analysis of patients ≥65 years or with mean participant age ≥70 years. Data extraction and synthesis: efficacy outcomes were mortality, hospitalisation for cardiovascular causes, symptom status or functional capacity. Safety outcomes were hyperkalaemia and renal dysfunction. Data were analysed using relative risk ratios with 95% confidence intervals. Relative risk ratios were pooled where more than three estimates were available. Results: seven RCTs were included (total n = 8,638). Three RCTs in HF with reduced ejection fraction (HEFREF) reported overall benefit from MRA therapy with no significant treatment interaction for age; the effects of MRAs on mortality in patients ≥75 years displayed marked inter-study heterogeneity. In four RCTs of HF with preserved ejection fraction (HEFPEF), MRA treatment had no significant effect on any efficacy outcome. Conclusions: MRAs improve clinical outcomes in selected cohorts of older patients with HEFREF but not HEFPEF. In patients ≥75 years with HEFREF, the effect of MRA treatment on overall mortality is uncertain. Further study is required in subgroups of elderly patients with both HEFREF and HEFPEF. [ABSTRACT FROM AUTHOR]
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- 2017
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166. Macrophages trigger cardiomyocyte proliferation by increasing epicardial vegfaa expression during larval zebrafish heart regeneration.
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Bruton, Finnius A., Kaveh, Aryan, Ross-Stewart, Katherine M., Matrone, Gianfranco, Oremek, Magdalena E.M., Solomonidis, Emmanouil G., Tucker, Carl S., Mullins, John J., Lucas, Christopher D., Brittan, Mairi, Taylor, Jonathan M., Rossi, Adriano G., and Denvir, Martin A.
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CARDIAC regeneration , *BRACHYDANIO , *MACROPHAGES , *HEART cells , *HEART injuries , *PERICARDIUM , *RNA sequencing - Abstract
Cardiac injury leads to the loss of cardiomyocytes, which are rapidly replaced by the proliferation of the surviving cells in zebrafish, but not in mammals. In both the regenerative zebrafish and non-regenerative mammals, cardiac injury induces a sustained macrophage response. Macrophages are required for cardiomyocyte proliferation during zebrafish cardiac regeneration, but the mechanisms whereby macrophages facilitate this crucial process are fundamentally unknown. Using heartbeat-synchronized live imaging, RNA sequencing, and macrophage-null genotypes in the larval zebrafish cardiac injury model, we characterize macrophage function and reveal that these cells activate the epicardium, inducing cardiomyocyte proliferation. Mechanistically, macrophages are specifically recruited to the epicardial-myocardial niche, triggering the expansion of the epicardium, which upregulates vegfaa expression to induce cardiomyocyte proliferation. Our data suggest that epicardial Vegfaa augments a developmental cardiac growth pathway via increased endocardial notch signaling. The identification of this macrophage-dependent mechanism of cardiac regeneration highlights immunomodulation as a potential strategy for enhancing mammalian cardiac repair. [Display omitted] • Heart regeneration in larval zebrafish is characterized in detail • Macrophage ablation blocks cardiomyocyte proliferation after cardiac injury • Macrophages synapse with epicardial cells and promote their proliferation • Epicardial Vegfaa drives cardiomyocyte proliferation during cardiac regeneration In this study, Bruton et al. test the requirement for macrophages for cardiac regeneration in larval zebrafish, finding macrophages to be necessary for cardiomyocyte proliferation via the activation of the epicardium. The identification of this macrophage-dependent mechanism of cardiac regeneration supports immunomodulation as a promising strategy for enhancing mammalian cardiac repair. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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167. Modulation of neointimal lesion formation by endogenous androgens is independent of vascular androgen receptor.
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Wu, Junxi, Hadoke, Patrick W. F., Mair, Iris, Lim, Win Gel, Miller, Eileen, Denvir, Martin A., and Smith, Lee B.
- Subjects
- *
ANDROGENS , *ANDROGEN receptors , *CARDIOVASCULAR diseases risk factors , *ATHEROSCLEROSIS , *ENDOTHELIAL cells , *LABORATORY mice - Abstract
Aims Low androgen levels have been linked with an increased risk of cardiovascular disease in men. Previous studies have suggested that androgens directly inhibit atherosclerotic lesion formation although the underlying mechanisms for this remain unclear. This study addressed the hypothesis that endogenous androgens inhibit arterial remodelling by a direct action on the androgen receptor (AR) in the vascular wall. Methods and results We studied a series of novel mouse lines with cell-specific deletion of the AR in either the endothelium or in smooth muscle cells or both cell types. Findings were compared with a model of global androgen deficiency in wild-type mice (castrated). We characterized the cardiovascular phenotype, vascular pharmacology and histology, and assessed neointimal lesion formation following vascular injury to the femoral artery. Cell-specific AR deletion did not alter body weight, circulating testosterone levels or seminal vesicle weight, but caused limited alterations in arterial contractility and blood pressure. Neointimal lesion formation was unaltered by selective deletion of AR from the vascular endothelium, smooth muscle, or both cell types. Castration in wild-type mice increased neointimal lesion volume (Sham vs. Castration: 2.4 × 107 ± 4.5 × 106 vs. 3.9 × 107 ± 4.9 × 106 µm3, P = 0.04, n = 9–10). Conclusion Vascular cell-specific AR deletion had no effect on neointimal lesion formation, while low systemic androgen levels adversely affect neointimal lesion size. These findings suggest that the cardio-protective effects of androgens are mediated either by AR outside the vasculature or by AR-independent mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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168. Telemonitoring for chronic heart failure: the views of patients and healthcare professionals - a qualitative study.
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Fairbrother, Peter, Ure, Jenny, Hanley, Janet, McCloughan, Lucy, Denvir, Martin, Sheikh, Aziz, and McKinstry, Brian
- Subjects
- *
ATTITUDE (Psychology) , *CONTINUUM of care , *HEART failure , *INTERVIEWING , *RESEARCH methodology , *MEDICAL personnel , *RESEARCH funding , *TELEMEDICINE , *EMPLOYEES' workload , *QUALITATIVE research , *THEMATIC analysis , *PATIENTS' attitudes - Abstract
Aims and objectives To understand the views of patients and professionals on the acceptability and perceived usefulness of telemonitoring in the management of chronic heart failure in the context of day-to-day care provision. Background There is an increasing interest in the potential for telemonitoring to support the home-based management of patients with chronic heart failure. However, little is known about the views of patients and professionals on the use of telemonitoring in this context. A chronic heart failure telemonitoring service was set-up by NHS Lothian, Scotland, to evaluate the intervention. Design A qualitative design was adopted to explore the views of patients and professionals participating in the service. Methods Semi-structured interviews were undertaken with 18 patients (61% male, mean age 75 years) and five professionals participating at different time points in this new service. Interviews were audio recorded, coded and thematically analysed using the Framework approach. Results Five main themes were identified: 'information, support and reassurance'; 'compliance and dependence'; 'changes and challenges'; 'determining the criteria for patient applicability to telemonitoring'; and 'continuity of care'. Conclusion Patients and professionals considered telemonitoring useful in the management of chronic heart failure, although with some caveats. Telemonitoring was popular with patients because they felt reassurance arising from what was perceived as continuous practitioner surveillance. Professionals expressed concern regarding perceived patient dependence on practitioner support. Increased workload was also a concern. Both groups acknowledged the need for improved technology and changes to service provision in order to better meet the intended objectives of the service. Relevance to clinical practice Although popular with patients, professionals emphasised the importance of case selection and adequate training and support, both for patients and themselves, in order to maximise the expected benefits of the service, particularly with regard to enabling self-management. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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169. Laser-targeted ablation of the zebrafish embryonic ventricle: A novel model of cardiac injury and repair.
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Matrone, Gianfranco, Taylor, Jonathan M., Wilson, Kathryn S., Baily, James, Love, Gordon D., Girkin, John M., Mullins, John J., Tucker, Carl S., and Denvir, Martin A.
- Subjects
- *
LASER ablation , *HEART cells , *GREEN fluorescent protein , *BRADYCARDIA , *HEART injuries , *CARDIAC surgery , *LABORATORY zebrafish - Abstract
Background: While the adult zebrafish (Danio rerio) heart demonstrates a remarkable capacity for self-renewal following apical resection little is known about the response to injury in the embryonic heart. Methods: Injury to the beating zebrafish embryo heart was induced by laser using a transgenic zebrafish expressing cardiomyocyte specific green fluorescent protein. Changes in ejection fraction (EF), heart rate (HR), and caudal vein blood flow (CVBF) assessed by video capture techniques were assessed at 2, 24 and 48h post-laser. Change in total and mitotic ventricular cardiomyocyte number following laser injury was also assessed by counting respectively DAPI (VCt) and Phospho-histone H3 (VCm) positive nuclei in isolated hearts using confocal microscopy. Results: Laser injury to the ventricle resulted in bradycardia and mild bleeding into the pericardium. At 2h post-laser injury, there was a significant reduction in cardiac performance in lasered-hearts compared with controls (HR 117±11 vs 167±9bpm, p≤0.001; EF 14.1±1.8 vs 20.1±1.3%, p≤0.001; CVBF 103±15 vs 316±13μms−1, p≤0.001, respectively). Isolated hearts showed a significant reduction in VCt at 2h post-laser compared to controls (195±15 vs 238±15, p≤0.05). Histology showed necrosis and apoptosis (TUNEL assay) at the site of laser injury. At 24h post-laser cardiac performance and VCt had recovered fully to control levels. Pretreatment with the cell-cycle inhibitor, aphidicolin, significantly inhibited functional recovery of the ventricle accompanied by a significant inhibition of cardiomyocyte proliferation. Conclusions: Laser-targeted injury of the zebrafish embryonic heart is a novel and reproducible model of cardiac injury and repair suitable for pharmacological and molecular studies. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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170. Assessing and addressing cardiovascular risk in adults with Turner syndrome.
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Turtle, Emma J., Sule, Ashish A., Bath, Louise E., Denvir, Martin, Gebbie, Ailsa, Mirsadraee, Saeed, and Webb, David J.
- Subjects
- *
HYPERTENSION , *CARDIOVASCULAR diseases , *GENOTYPE-environment interaction , *CELL nuclei , *ANTHROPOMETRY - Abstract
Turner syndrome ( TS), the result of a structurally abnormal or absent X chromosome, occurs in one in 2 000 live born females. The phenotype is highly variable, but short stature and gonadal dysgenesis are usually present. The main objective in adults with TS is health surveillance, but TS still causes a reduction in life expectancy of up to 13 years, with cardiovascular disease, congenital or acquired, as the major cause of an early death. While it has been established that all women with TS should undergo in-depth cardiovascular examination at diagnosis, advice on the cardiovascular management of women with TS is limited. Here, we provide a summary of our current practice within a multidisciplinary team, supported by our expertise in various aspects of cardiovascular risk management, and the evidence from research where it is available, with the aim of providing optimal support to our patients with TS. Background A dedicated Adult Turner Clinic was established in South East Scotland in 2002. This gynaecology-led clinic serves a population of roughly 1·2 million and, currently, reviews around 50 women with TS annually. Referrals for adult care come from paediatrics or general practice. Following a series of individual case discussions regarding the management of more complex cardiovascular problems, we have assembled a dedicated multidisciplinary group to determine a timely cardiovascular screening strategy, a basis for specialist referral, and appropriate hypertension management. This team now includes a paediatric endocrinologist, gynaecologist, cardiologist (with an interest in inherited disorders), vascular radiologist and hypertension specialist. Here, we review the literature on cardiovascular disease in women with TS and, make recommendations, based on relatively limited high-quality evidence, together with our experience, on the optimal timing of cardiovascular screening. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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171. 18F-SODIUM FLUORIDE POSITRON EMISSION TOMOGRAPHY / COMPUTED TOMOGRAPHY IN ACUTE AORTIC SYNDROME.
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Syed, Maaz J., Fletcher, Alexander, Debono, Samuel, Forsythe, Rachael, Williams, Michelle, Tavarez, Adriana, Wallace, William A., Denvir, Martin, Falah, Orwa, Tambyraja, Andrew, Chalmers, Roderick, Van Beek, Edwin, Dweck, Marc, and Newby, David
- Subjects
- *
POSITRON emission tomography computed tomography , *COMPUTED tomography , *FLUORIDES , *AORTIC dissection - Published
- 2021
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172. Implications of lowering threshold of plasma troponin concentration in diagnosis of myocardial infarction: cohort study.
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Mills, Nicholas L., Kuan Ken Lee, McAllister, David A., Churchhouse, Antonia M. D., MacLeod, Margaret, Stoddart, Mary, Walker, Simon, Denvir, Martin A., Fox, Keith A. A., and Newby, David E.
- Subjects
- *
CONFIDENCE intervals , *EPIDEMIOLOGY , *LONGITUDINAL method , *PROBABILITY theory , *RESEARCH funding , *DATA analysis , *TROPONIN , *DESCRIPTIVE statistics ,MYOCARDIAL infarction diagnosis - Abstract
The article offers information on a study regarding the implications of lowering the diagnostic threshold of plasma troponin concentration to the 99th centile. According to the results, it increased the diagnosis of myocardial infarction by 47 percent and identified patients who were 4 to5 times more likely to die or have a recurrent myocardial infarct than those below this threshold.
- Published
- 2012
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173. Systematic hand-held echocardiography in patients hospitalised with acute coronary syndrome.
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Geers J, Balfour A, Molek P, Barron P, Botezatu S, Joshi SS, White A, Buchwald M, Everett R, McCarley J, Cusack D, Japp AG, Gibson PH, Lang CCE, Stirrat C, Grubb NR, Bing R, Cruden NL, Denvir MA, Soliman Aboumarie H, Cosyns B, Newby DE, and Dweck MR
- Abstract
Aims: Transthoracic echocardiography is recommended in all patients with acute coronary syndrome but is time-consuming and lacks an evidence base. We aimed to assess the feasibility, diagnostic accuracy and time-efficiency of hand-held echocardiography in patients with acute coronary syndrome and describe the impact of echocardiography on clinical management in this setting., Methods and Results: Patients with acute coronary syndrome underwent both hand-held and transthoracic echocardiography with agreement between key imaging parameters assessed using kappa statistics. The immediate clinical impact of hand-held echocardiography in this population was systematically evaluated.Overall, 262 patients (65±12 years, 71% male) participated. Agreement between hand-held and transthoracic echocardiography was good-to-excellent (kappa 0.60-1.00) with hand-held echocardiography having an overall negative predictive value of 95%. Hand-held echocardiography was performed rapidly (7.7±1.6 min) and completed a median of 5 [interquartile range 3-20] hours earlier than transthoracic echocardiography. Systematic hand-held echocardiography in all patients with acute coronary syndrome identified an important cardiac abnormality in 50% and the clinical management plan was changed by echocardiography in 42%. In 85% of cases, hand-held echocardiography was sufficient for patient decision-making and transthoracic echocardiography was no longer deemed necessary., Conclusions: In patients with acute coronary syndrome, hand-held echocardiography provides comparable results to transthoracic echocardiography, can be more rapidly applied and gives sufficient imaging information for decision-making in the vast majority of patients. Systematic echocardiography has clinical impact in half of patients, supporting the clinical utility of echocardiography in this population, and providing an evidence-base for current guidelines., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)
- Published
- 2024
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174. Criteria for Referral of Patients With Advanced Heart Failure for Specialized Palliative Care.
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Chang YK, Allen LA, McClung JA, Denvir MA, Philip J, Mori M, Perez-Cruz P, Cheng SY, Collins A, and Hui D
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- Consensus, Humans, Outpatients, Referral and Consultation, Heart Failure therapy, Palliative Care
- Abstract
Background: Patients with advanced heart failure have substantial supportive care needs. Specialist palliative care can be beneficial, but it is unclear who is most appropriate for referral and when patients should be referred., Objectives: We conducted a Delphi study of international experts to identify consensus referral criteria for specialist palliative care for patients with advanced heart failure., Methods: Clinicians from 5 continents with expertise in the integration of cardiology and palliative care were asked to rate 34 disease-based, 24 needs-based, and 9 time-based criteria over 3 rounds. Consensus was defined a priori as ≥70% agreement. A criterion was coded as major if the experts endorsed that meeting that criterion alone was adequate to justify a referral., Results: The response rate was 44 of 46 (96%), 41 of 46 (89%), and 43 of 46 (93%) in the first, second, and third rounds, respectively. Panelists reached consensus on 25 major criteria for specialist palliative care referral. The 25 major criteria were categorized under 6 topics, including "advanced/refractory heart failure, comorbidities, and complications" (eg, cardiac cachexia, cardiorenal syndrome) (n = 8), "advanced heart failure therapies" (eg, chronic inotropes, precardiac transplant) (n = 4), "hospital utilization" (eg, emergency room visits, hospitalization) (n = 2), "prognostic estimate" (n = 1), "symptom burden/distress" (eg, severe physical/emotional/spiritual distress) (n = 6), and "decision making/social support" (eg, goals-of-care discussions) (n = 4). The majority (68%) of major criteria had ≥90% agreement., Conclusions: International experts reached consensus on a large number of criteria for referral to specialist palliative care. With further validation, these criteria may be useful for standardizing palliative care access in the inpatient and/or outpatient settings., Competing Interests: Funding Support and Author Disclosures Dr Hui has received grants from the National Institutes of Health (NIH) National Cancer Institute (R01CA214960, R01CA225701, and R01CA231471). The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)
- Published
- 2022
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175. 18 F-Sodium Fluoride Positron Emission Tomography and Computed Tomography in Acute Aortic Syndrome.
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Syed MBJ, Fletcher AJ, Debono S, Forsythe RO, Williams MC, Dweck MR, Shah ASV, Macaskill MG, Tavares A, Denvir MA, Lim K, Wallace WA, Kaczynski J, Clark T, Sellers SL, Masson N, Falah O, Chalmers RTA, Tambyraja AL, van Beek EJR, and Newby DE
- Subjects
- Aorta diagnostic imaging, Fluorine Radioisotopes, Humans, Positron Emission Tomography Computed Tomography methods, Positron-Emission Tomography, Predictive Value of Tests, Radiopharmaceuticals, Risk Factors, Sodium Fluoride, Tomography, X-Ray Computed, Calcinosis, Coronary Artery Disease, Plaque, Atherosclerotic
- Abstract
Background: Acute aortic syndrome is associated with aortic medial degeneration.
18 F-sodium fluoride (18 F-NaF) positron emission tomography (PET) detects microscopic tissue calcification as a marker of disease activity., Objectives: In a proof-of-concept study, this investigation aimed to establish whether18 F-NaF PET combined with computed tomography (CT) angiography could identify aortic medial disease activity in patients with acute aortic syndrome., Methods: Patients with aortic dissection or intramural hematomas and control subjects underwent18 F-NaF PET/CT angiography of the aorta. Aortic18 F-NaF uptake was measured at the most diseased segment, and the maximum value was corrected for background blood pool activity (maximum tissue-to-background ratio [TBRmax ]). Radiotracer uptake was compared with change in aortic size and major adverse aortic events (aortic rupture, aorta-related death, or aortic repair) over 45 ± 13 months., Results: Aortic18 F-NaF uptake co-localized with histologically defined regions of microcalcification and elastin disruption. Compared with control subjects, patients with acute aortic syndrome had increased18 F-NaF uptake (TBRmax : 1.36 ± 0.39 [n = 20] vs 2.02 ± 0.42 [n = 47] respectively; P < 0.001) with enhanced uptake at the site of intimal disruption (+27.5%; P < 0.001).18 F-NaF uptake in the false lumen was associated with aortic growth (+7.1 mm/year; P = 0.011), and uptake in the outer aortic wall was associated with major adverse aortic events (HR: 8.5 [95% CI: 1.4-50.4]; P = 0.019)., Conclusions: In patients with acute aortic syndrome,18 F-NaF uptake was enhanced at sites of disease activity and was associated with aortic growth and clinical events.18 F-NaF PET/CT holds promise as a noninvasive marker of disease severity and future risk in patients with acute aortic syndrome. (18 F Sodium Fluoride PET/CT in Acute Aortic Syndrome [FAASt]; NCT03647566)., Competing Interests: Funding Support and Author Disclosure All funding support is from the United Kingdom. Mr Syed and Drs Fletcher, Dweck, Shah, and Tavares, Mr Kaczynki, and Dr Newby were supported by the British Heart Foundation (FS/18/31/33676, FS/19/15/34155, FS/11/014, FS/14/78/31020, CH/09/002, RG/16/10/32375, RE/18/5/34216). Dr Dweck has received the Sir Jules Thorn Award for Biomedical Research 2015 (15/JTA). Dr Newby has received a Wellcome Trust Senior Investigator Award (WT103782AIA). Dr van Beek has been supported by the Scottish Imaging Network—a Platform of Scientific Excellence (SINAPSE). Edinburgh Clinical Research Facility and Edinburgh Imaging Facility are supported by NHS Research Scotland. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022. Published by Elsevier Inc.)- Published
- 2022
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176. Selective Cdk9 inhibition resolves neutrophilic inflammation and enhances cardiac regeneration in larval zebrafish.
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Kaveh A, Bruton FA, Oremek MEM, Tucker CS, Taylor JM, Mullins JJ, Rossi AG, and Denvir MA
- Subjects
- Animals, Cyclin-Dependent Kinase 9 metabolism, Inflammation drug therapy, Inflammation enzymology, Zebrafish, Zebrafish Proteins metabolism, Cyclin-Dependent Kinase 9 antagonists & inhibitors, Flavonoids pharmacology, Myocardium enzymology, Neutrophils enzymology, Piperidines pharmacology, Pyrazoles pharmacology, Regeneration drug effects, Zebrafish Proteins antagonists & inhibitors
- Abstract
Sustained neutrophilic inflammation is detrimental for cardiac repair and associated with adverse outcomes following myocardial infarction (MI). An attractive therapeutic strategy to treat MI is to reduce or remove infiltrating neutrophils to promote downstream reparative mechanisms. CDK9 inhibitor compounds enhance the resolution of neutrophilic inflammation; however, their effects on cardiac repair/regeneration are unknown. We have devised a cardiac injury model to investigate inflammatory and regenerative responses in larval zebrafish using heartbeat-synchronised light-sheet fluorescence microscopy. We used this model to test two clinically approved CDK9 inhibitors, AT7519 and flavopiridol, examining their effects on neutrophils, macrophages and cardiomyocyte regeneration. We found that AT7519 and flavopiridol resolve neutrophil infiltration by inducing reverse migration from the cardiac lesion. Although continuous exposure to AT7519 or flavopiridol caused adverse phenotypes, transient treatment accelerated neutrophil resolution while avoiding these effects. Transient treatment with AT7519, but not flavopiridol, augmented wound-associated macrophage polarisation, which enhanced macrophage-dependent cardiomyocyte number expansion and the rate of myocardial wound closure. Using cdk9-/- knockout mutants, we showed that AT7519 is a selective CDK9 inhibitor, revealing the potential of such treatments to promote cardiac repair/regeneration., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)
- Published
- 2022
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177. Isolation of Cardiac Endothelial Cells for Transcriptomic Analysis of the Zebrafish and Mouse Heart.
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Li Z, Ross Stewart KM, Bruton FA, Denvir MA, and Brittan M
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- Animals, Gene Expression Profiling methods, Heart, Mice, Transcriptome, Endothelial Cells, Zebrafish genetics
- Abstract
Isolation of high quality cardiac endothelial cells is a prerequisite for successful bulk and single cell sequencing for RNA (scRNA-seq). We describe a protocol using both enzymatic and mechanical dissociation and fluorescence-activated cell sorting (FACS) to isolate endothelial cells from larval and adult zebrafish hearts and from healthy and ischemic adult mouse hearts. Endothelial cells with high viability and purity can be obtained using this method for downstream transcriptional analyses applications., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
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178. Corticosteroid Receptors in Cardiac Health and Disease.
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Ivy JR, Gray GA, Holmes MC, Denvir MA, and Chapman KE
- Subjects
- Animals, Myocytes, Cardiac metabolism, Receptors, Glucocorticoid physiology, Receptors, Thyroid Hormone metabolism, Heart Failure metabolism, Receptors, Mineralocorticoid
- Abstract
Nuclear receptors play a central role in both energy metabolism and cardiomyocyte death and survival in the heart. Recent evidence suggests they may also influence cardiomyocyte endowment. Although several members of the nuclear receptor family play key roles in heart maturation (including thyroid hormone receptors) and cardiac metabolism, here, the focus will be on the corticosteroid receptors, the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). The heart is an important target for the actions of corticosteroids, yet the homeostatic role of GR and MR in the healthy heart has been elusive. However, MR antagonists are important in the treatment of heart failure, a condition associated with mitochondrial dysfunction and energy failure in cardiomyocytes leading to mitochondria-initiated cardiomyocyte death (Ingwall and Weiss, Circ Res 95:135-145, 2014; Ingwall , Cardiovasc Res 81:412-419, 2009; Zhou and Tian , J Clin Invest 128:3716-3726, 2018). In contrast, animal studies suggest GR activation in cardiomyocytes has a cardioprotective role, including in heart failure., (© 2022. The Author(s), under exclusive license to Springer Nature Switzerland AG.)
- Published
- 2022
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179. Nuclear S-nitrosylation impacts tissue regeneration in zebrafish.
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Matrone G, Jung SY, Choi JM, Jain A, Leung HE, Rajapakshe K, Coarfa C, Rodor J, Denvir MA, Baker AH, and Cooke JP
- Subjects
- Animals, Cell Nucleus genetics, Co-Repressor Proteins genetics, Co-Repressor Proteins metabolism, Female, Histone Demethylases genetics, Histone Demethylases metabolism, Male, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, Signal Transduction, Zebrafish genetics, Zebrafish Proteins genetics, Zebrafish Proteins metabolism, Animal Fins physiology, Cell Nucleus metabolism, Nitric Oxide metabolism, Regeneration, Tail physiology, Zebrafish physiology
- Abstract
Despite the importance of nitric oxide signaling in multiple biological processes, its role in tissue regeneration remains largely unexplored. Here, we provide evidence that inducible nitric oxide synthase (iNos) translocates to the nucleus during zebrafish tailfin regeneration and is associated with alterations in the nuclear S-nitrosylated proteome. iNos inhibitors or nitric oxide scavengers reduce protein S-nitrosylation and impair tailfin regeneration. Liquid chromatography/tandem mass spectrometry reveals an increase of up to 11-fold in the number of S-nitrosylated proteins during regeneration. Among these, Kdm1a, a well-known epigenetic modifier, is S-nitrosylated on Cys334. This alters Kdm1a binding to the CoRest complex, thus impairing its H3K4 demethylase activity, which is a response specific to the endothelial compartment. Rescue experiments show S-nitrosylation is essential for tailfin regeneration, and we identify downstream endothelial targets of Kdm1a S-nitrosylation. In this work, we define S-nitrosylation as an essential post-translational modification in tissue regeneration., (© 2021. The Author(s).)
- Published
- 2021
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180. PET/CT Technology in Adult Zebrafish: A Pilot Study Toward Live Longitudinal Imaging.
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Tucker C, Collins R, Denvir MA, and McDougald WA
- Abstract
Decades of research have confirmed the beneficial and advantageous use of zebrafish ( Danio rerio ) as a model of human disease in biomedical studies. Not only are 71% of human genes shared with the zebrafish many of these genes are linked to human diseases. Currently, numerous transgenic and mutant genetic zebrafish lines are now widely available for use in research. Furthermore, zebrafish are relatively inexpensive to maintain compared to rodents. However, a limiting factor to fully utilising adult zebrafish in research is not the fish but the technological imaging tools available. In order to increase the utilisation of adult zebrafish, which are not naturally transparent, requires new imaging approaches. Therefore, this feasibility study: (1) presents an innovative designed PET/CT adult zebrafish imaging platform, capable of maintaining normal aquatic physiology during scanning; (2) assesses the practical aspects of adult zebrafish imaging; and (3) set basic procedural guidelines for zebrafish imaging during a PET/CT acquisition. Methods: With computer aided design (CAD) software an imaging platform was developed for 3D printing. A 3D printed zebrafish model was created from a CT acquisition of a zebrafish using the CAD software. This model and subsequently euthanised zebrafish were imaged post-injection using different concentrations of the radiotracer [
18 F]FDG with CT contrast. Results: PET/CT imaging was successful, revealing levels as low as 0.01 MBq could be detected in the fish. In the zebrafish imaging post-injection distribution of the radiotracer was observed away from the injection site as well as tissue uptake. Potential preliminary husbandry and welfare guidelines for the fish during and after PET/CT imaging were determined. Conclusion: Using PET/CT for adult zebrafish imaging as a viable non-invasive technological tool is feasible. Adult zebrafish PET/CT imaging has the potential to be a key imaging technique offering the possibilities of enhanced biomedical understanding and new translational data sets., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Tucker, Collins, Denvir and McDougald.)- Published
- 2021
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181. Fli1 + cells transcriptional analysis reveals an Lmo2-Prdm16 axis in angiogenesis.
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Matrone G, Xia B, Chen K, Denvir MA, Baker AH, and Cooke JP
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- Animals, Animals, Genetically Modified, Cell Differentiation, DNA-Binding Proteins genetics, Embryo, Nonmammalian, Gene Expression Regulation, Developmental, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, Humans, Platelet Endothelial Cell Adhesion Molecule-1 genetics, Platelet Endothelial Cell Adhesion Molecule-1 metabolism, RNA-Seq, Transcriptome, Up-Regulation, Zebrafish, Zebrafish Proteins genetics, DNA-Binding Proteins metabolism, Endothelial Cells physiology, Induced Pluripotent Stem Cells physiology, Neovascularization, Physiologic physiology, Proto-Oncogene Protein c-fli-1 physiology, Zebrafish Proteins metabolism
- Abstract
A network of molecular factors drives the development, differentiation, and maintenance of endothelial cells. Friend leukemia integration 1 transcription factor (FLI1) is a bona fide marker of endothelial cells during early development. In zebrafish Tg( f li1:EGFP)
y1 , we identified two endothelial cell populations, high- fli1+ and low- fli1+ , by the intensity of green fluorescent protein signal. By comparing RNA-sequencing analysis of non- fli1 expressing cells ( fli1- ) with these two ( fli1+ ) cell populations, we identified several up-regulated genes, not previously recognized as important, during endothelial development. Compared with fli1- and low- fli1+ cells, high- fli1+ cells showed up-regulated expression of the zinc finger transcription factor PRDI-BF1 and RIZ homology domain containing 16 ( prdm16 ). Prdm16 knockdown (KD) by morpholino in the zebrafish larva was associated with impaired angiogenesis and increased number of low- fli1 This work unveils a mechanism by which+ expression is activated in endothelial cells by Lmo2 and highlights a possible therapeutic pathway by which to modulate endothelial cell growth and repair.fli1+ cells. In addition, PRDM16 KD in endothelial cells derived from human-induced pluripotent stem cells impaired their differentiation and migration in vitro. Moreover, zebrafish mutants (mut) with loss of function for the oncogene LIM domain only 2 ( lmo2 ) also showed reduced prdm16 gene expression combined with impaired angiogenesis. Prdm16 expression was reduced further in endothelial (CD31+ ) cells compared with CD31- cells isolated from l mo2 -mutants ( l mo2- mut) embryos. Chromatin immunoprecipitation-PCR demonstrated that Lmo2 binds to the promoter and directly regulates the transcription of prdm16 This work unveils a mechanism by which prdm16 expression is activated in endothelial cells by Lmo2 and highlights a possible therapeutic pathway by which to modulate endothelial cell growth and repair., Competing Interests: The authors declare no competing interest.- Published
- 2021
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182. Cardiac Energetics Before, During, and After Anthracycline-Based Chemotherapy in Breast Cancer Patients Using 31 P Magnetic Resonance Spectroscopy: A Pilot Study.
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Macnaught G, Oikonomidou O, Rodgers CT, Clarke W, Cooper A, McVicars H, Hayward L, Mirsadraee S, Semple S, and Denvir MA
- Abstract
Purpose: To explore the utility of phosphorus magnetic resonance spectroscopy (
31 P MRS) in identifying anthracycline-induced cardiac toxicity in patients with breast cancer. Methods: Twenty patients with newly diagnosed breast cancer receiving anthracycline-based chemotherapy had cardiac magnetic resonance assessment of left ventricular ejection fraction (LVEF) and31 P MRS to determine myocardial Phosphocreatine/Adenosine Triphosphate Ratio (PCr/ATP) at three time points: pre-, mid-, and end-chemotherapy. Plasma high sensitivity cardiac troponin-I (cTn-I) tests and electrocardiograms were also performed at these same time points. Results: Phosphocreatine/Adenosine Triphosphate did not change significantly between pre- and mid-chemo (2.16 ± 0.46 vs. 2.00 ± 0.56, p = 0.80) and pre- and end-chemo (2.16 ± 0.46 vs. 2.17 ± 0.86, p = 0.99). Mean LVEF reduced significantly by 5.1% between pre- and end-chemo (61.4 ± 4.4 vs. 56.3 ± 8.1 %, p = 0.02). Change in PCr/ATP ratios from pre- to end-chemo correlated inversely with changes in LVEF over the same period ( r = -0.65, p = 0.006). Plasma cTn-I increased progressively during chemotherapy from pre- to mid-chemo (1.35 ± 0.81 to 4.40 ± 2.64 ng/L; p = 0.01) and from mid- to end-chemo (4.40 ± 2.64 to 18.33 ± 13.23 ng/L; p = 0.001). Conclusions: In this small cohort pilot study, we did not observe a clear change in mean PCr/ATP values during chemotherapy despite evidence of increased plasma cardiac biomarkers and reduced LVEF. Future similar studies should be adequately powered to take account of patient drop-out and variable changes in PCr/ATP and could include T1 and T2 mapping., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Macnaught, Oikonomidou, Rodgers, Clarke, Cooper, McVicars, Hayward, Mirsadraee, Semple and Denvir.)- Published
- 2021
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183. Chest pain presentations to hospital during the COVID-19 lockdown: Lessons for public health media campaigns.
- Author
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Ferry AV, Keanie C, Denvir MA, Mills NL, and Strachan FE
- Subjects
- Adult, Aged, Aged, 80 and over, Emergency Service, Hospital, Female, Humans, Male, Middle Aged, Patient Acceptance of Health Care, Qualitative Research, Quarantine, Scotland, Surveys and Questionnaires, COVID-19 epidemiology, Chest Pain epidemiology, Help-Seeking Behavior, Pandemics
- Abstract
Objective: Emergency Department (ED) attendances with chest pain reduced during the COVID-19 lockdown. We performed a service evaluation project in NHS Lothian to explore how and why the COVID-19 pandemic and public health advice had affected chest pain presentations and help-seeking behaviour at an individual patient level using a qualitative interview approach., Methods: We carried out 28 semi-structured telephone interviews with a convenience sample of patients who presented with chest pain during lockdown and in patients with known coronary heart disease under the outpatient care of a cardiologist in April and May 2020. Interviews were audio recorded and voice files listened to while making detailed notes. Salient themes and issues were documented as verbatim extracts. Interviews were analysed thematically., Results: Patient interviews revealed three main themes. 1) pandemic help-seeking behaviour; describing how participants made the decision to seek professional healthcare assessment. 2) COVID-19 exposure concerns; describing how the subthemes of perceived vulnerability, wishing to protect others and adding pressure to the health service shaped their decision making for an episode of acute chest pain. 3) hospital experience; describing the difference between the imagined and actual experience in hospital., Conclusions: Qualitative interviews revealed how the pandemic shaped help-seeking practices, how patients interpreted their personal vulnerability to the virus, and described patient experience of attending hospital for assessment during this time. As patient numbers presenting to hospital appeared to mirror public health messaging, dynamic monitoring of this messaging should evaluate public response to healthcare campaigns to ensure the net impact on health, pandemic and non-pandemic related, is optimised., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
- Full Text
- View/download PDF
184. Live Imaging of Heart Injury in Larval Zebrafish Reveals a Multi-Stage Model of Neutrophil and Macrophage Migration.
- Author
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Kaveh A, Bruton FA, Buckley C, Oremek MEM, Tucker CS, Mullins JJ, Taylor JM, Rossi AG, and Denvir MA
- Abstract
Neutrophils and macrophages are crucial effectors and modulators of repair and regeneration following myocardial infarction, but they cannot be easily observed in vivo in mammalian models. Hence many studies have utilized larval zebrafish injury models to examine neutrophils and macrophages in their tissue of interest. However, to date the migratory patterns and ontogeny of these recruited cells is unknown. In this study, we address this need by comparing our larval zebrafish model of cardiac injury to the archetypal tail fin injury model. Our in vivo imaging allowed comprehensive mapping of neutrophil and macrophage migration from primary hematopoietic sites, to the wound. Early following injury there is an acute phase of neutrophil recruitment that is followed by sustained macrophage recruitment. Both cell types are initially recruited locally and subsequently from distal sites, primarily the caudal hematopoietic tissue (CHT). Once liberated from the CHT, some neutrophils and macrophages enter circulation, but most use abluminal vascular endothelium to crawl through the larva. In both injury models the innate immune response resolves by reverse migration, with very little apoptosis or efferocytosis of neutrophils. Furthermore, our in vivo imaging led to the finding of a novel wound responsive mpeg1 + neutrophil subset, highlighting previously unrecognized heterogeneity in neutrophils. Our study provides a detailed analysis of the modes of immune cell migration in larval zebrafish, paving the way for future studies examining tissue injury and inflammation., (Copyright © 2020 Kaveh, Bruton, Buckley, Oremek, Tucker, Mullins, Taylor, Rossi and Denvir.)
- Published
- 2020
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185. Referral Criteria to Palliative Care for Patients With Heart Failure: A Systematic Review.
- Author
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Chang YK, Kaplan H, Geng Y, Mo L, Philip J, Collins A, Allen LA, McClung JA, Denvir MA, and Hui D
- Subjects
- Humans, Heart Failure therapy, Palliative Care, Referral and Consultation
- Abstract
Background: Patients with heart failure have significant symptom burden, care needs, and often a progressive course to end-stage disease. Palliative care referrals may be helpful but it is currently unclear when patients should be referred and by whom. We conducted a systematic review of the literature to examine referral criteria for palliative care among patients with heart failure., Methods: We searched Ovid, MEDLINE, Ovid Embase, and PubMed databases for articles in the English language from the inception of databases to January 17, 2019 related to palliative care referral in patients with heart failure. Two investigators independently reviewed each citation for inclusion and then extracted the referral criteria. Referral criteria were then categorized thematically., Results: Of the 1199 citations in our initial search, 102 articles were included in the final sample. We identified 18 categories of referral criteria, including 7 needs-based criteria and 10 disease-based criteria. The most commonly discussed criterion was physical or emotional symptoms (n=51 [50%]), followed by cardiac stage (n=46 [45%]), hospital utilization (n=38 [37%]), prognosis (n=37 [36%]), and advanced cardiac therapies (n=36 [35%]). Under cardiac stage, 31 (30%) articles suggested New York Heart Association functional class ≥III and 12 (12%) recommended New York Heart Association class ≥IV as cutoffs for referral. Prognosis of ≤1 year was mentioned in 21 (21%) articles as a potential trigger; few other criteria had specific cutoffs., Conclusions: This systematic review highlighted the lack of consensus regarding referral criteria for the involvement of palliative care in patients with heart failure. Further research is needed to identify appropriate and timely triggers for palliative care referral.
- Published
- 2020
- Full Text
- View/download PDF
186. Author Correction: Adaptive prospective optical gating enables day-long 3D time-lapse imaging of the beating embryonic zebrafish heart.
- Author
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Taylor JM, Nelson CJ, Bruton FA, Kaveh A, Buckley C, Tucker CS, Rossi AG, Mullins JJ, and Denvir MA
- Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
- Published
- 2020
- Full Text
- View/download PDF
187. Frailty assessment and risk prediction by GRACE score in older patients with acute myocardial infarction.
- Author
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Anand A, Cudmore S, Robertson S, Stephen J, Haga K, Weir CJ, Murray SA, Boyd K, Gunn J, Iqbal J, MacLullich A, Shenkin SD, Fox KAA, Mills N, and Denvir MA
- Subjects
- Acute Coronary Syndrome complications, Aged, Aged, 80 and over, Angiotensin Receptor Antagonists, Angiotensin-Converting Enzyme Inhibitors therapeutic use, Cohort Studies, Female, Humans, Male, Myocardial Infarction diagnosis, Myocardial Infarction drug therapy, Prognosis, Prospective Studies, Registries, Risk Factors, Acute Coronary Syndrome epidemiology, Frailty diagnosis, Myocardial Infarction epidemiology, Risk Assessment methods
- Abstract
Background: Risk prediction after myocardial infarction is often complex in older patients. The Global Registry of Acute Coronary Events (GRACE) model includes clinical parameters and age, but not frailty. We hypothesised that frailty would enhance the prognostic properties of GRACE., Methods: We performed a prospective observational cohort study in two independent cardiology units: the Royal Infirmary of Edinburgh, UK (primary cohort) and the South Yorkshire Cardiothoracic Centre, Sheffield, UK (external validation). The study sample included 198 patients ≥65 years old hospitalised with type 1 myocardial infarction (primary cohort) and 96 patients ≥65 years old undergoing cardiac catheterisation for myocardial infarction (external validation). Frailty was assessed using the Clinical Frailty Scale (CFS). The GRACE 2.0 estimated risk of 12-month mortality, Charlson comorbidity index and Karnofsky disability scale were also determined for each patient., Results: Forty (20%) patients were frail (CFS ≥5). These individuals had greater comorbidity, functional impairment and a higher risk of death at 12 months (49% vs. 9% in non-frail patients, p < 0.001). The hazard of 12-month all-cause mortality nearly doubled per point increase in CFS after adjustment for age, sex and comorbidity (Hazard Ratio [HR] 1.90, 95% CI 1.47-2.44, p < 0.001). The CFS had good discrimination for mortality by Receiver Operating Characteristic (ROC) curve analysis (Area Under the Curve [AUC] 0.81, 95% CI 0.72-0.89) and enhanced the GRACE estimate (AUC 0.86 vs. 0.80 without CFS, p = 0.04). At existing GRACE thresholds, the CFS resulted in a Net Reclassification Improvement (NRI) of 0.44 (95% CI 0.28-0.60, p < 0.001), largely through reductions in risk estimates amongst non-frail patients. Similar findings were observed in the external validation cohort (NRI 0.46, 95% CI 0.23-0.69, p < 0.001)., Conclusions: The GRACE score overestimated mortality risk after myocardial infarction in these cohorts of older patients. The CFS is a simple guided frailty tool that may enhance prediction in this setting. These findings merit evaluation in larger cohorts of unselected patients., Trial Registration: Clinicaltrials.gov; NCT02302014 (November 26th 2014, retrospectively registered).
- Published
- 2020
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- View/download PDF
188. Adaptive prospective optical gating enables day-long 3D time-lapse imaging of the beating embryonic zebrafish heart.
- Author
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Taylor JM, Nelson CJ, Bruton FA, Kaveh A, Buckley C, Tucker CS, Rossi AG, Mullins JJ, and Denvir MA
- Subjects
- Algorithms, Animals, Female, Male, Myocardial Contraction, Zebrafish physiology, Heart embryology, Heart physiology, Imaging, Three-Dimensional methods, Time-Lapse Imaging methods, Zebrafish embryology
- Abstract
Three-dimensional fluorescence time-lapse imaging of the beating heart is extremely challenging, due to the heart's constant motion and a need to avoid pharmacological or phototoxic damage. Although real-time triggered imaging can computationally "freeze" the heart for 3D imaging, no previous algorithm has been able to maintain phase-lock across developmental timescales. We report a new algorithm capable of maintaining day-long phase-lock, permitting routine acquisition of synchronised 3D + time video time-lapse datasets of the beating zebrafish heart. This approach has enabled us for the first time to directly observe detailed developmental and cellular processes in the beating heart, revealing the dynamics of the immune response to injury and witnessing intriguing proliferative events that challenge the established literature on cardiac trabeculation. Our approach opens up exciting new opportunities for direct time-lapse imaging studies over a 24-hour time course, to understand the cellular mechanisms underlying cardiac development, repair and regeneration.
- Published
- 2019
- Full Text
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189. High-sensitivity cardiac troponin I and risk of heart failure in patients with suspected acute coronary syndrome: a cohort study.
- Author
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Stelzle D, Shah ASV, Anand A, Strachan FE, Chapman AR, Denvir MA, Mills NL, and McAllister DA
- Subjects
- Acute Coronary Syndrome complications, Acute Coronary Syndrome diagnosis, Aged, Biomarkers blood, Female, Heart Failure etiology, Humans, Male, Middle Aged, Predictive Value of Tests, Prognosis, Risk Factors, Acute Coronary Syndrome blood, Heart Failure blood, Troponin I blood
- Abstract
Aims: Heart failure may occur following acute myocardial infarction, but with the use of high-sensitivity cardiac troponin assays we increasingly diagnose patients with minor myocardial injury. Whether troponin concentrations remain a useful predictor of heart failure in patients with acute coronary syndrome is uncertain., Methods and Results: We identified all consecutive patients (n = 4748) with suspected acute coronary syndrome (61 ± 16 years, 57% male) presenting to three secondary and tertiary care hospitals. Cox-regression models were used to evaluate the association between high-sensitivity cardiac troponin I concentration and subsequent heart failure hospitalization. C-statistics were estimated to evaluate the predictive value of troponin for heart failure hospitalization. Over 2071 years of follow-up there were 83 heart failure hospitalizations. Patients with troponin concentrations above the upper reference limit (URL) were more likely to be hospitalized with heart failure than patients below the URL (118/1000 vs. 17/1000 person years, adjusted hazard ratio: 7.0). Among patients with troponin concentrations
- Published
- 2018
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- View/download PDF
190. Cardiovascular outcomes with an inhaled beta2-agonist/corticosteroid in patients with COPD at high cardiovascular risk.
- Author
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Brook RD, Anderson JA, Calverley PM, Celli BR, Crim C, Denvir MA, Magder S, Martinez FJ, Rajagopalan S, Vestbo J, Yates J, and Newby DE
- Subjects
- Administration, Inhalation, Adrenergic beta-2 Receptor Antagonists administration & dosage, Adult, Aged, Aged, 80 and over, Cardiovascular Diseases etiology, Cardiovascular Diseases physiopathology, Dose-Response Relationship, Drug, Double-Blind Method, Drug Combinations, Female, Follow-Up Studies, Forced Expiratory Volume, Glucocorticoids administration & dosage, Humans, Male, Middle Aged, Pulmonary Disease, Chronic Obstructive complications, Pulmonary Disease, Chronic Obstructive physiopathology, Risk Factors, Treatment Outcome, Androstadienes administration & dosage, Benzyl Alcohols administration & dosage, Cardiovascular Diseases drug therapy, Chlorobenzenes administration & dosage, Pulmonary Disease, Chronic Obstructive drug therapy
- Abstract
Objectives: Cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) often coexist. We assessed the effect of inhaled COPD treatments on CVD outcomes and safety in patients with COPD and at heightened CVD risk., Methods: The SUMMIT (Study to Understand Mortality and MorbidITy) was a multicentre, randomised, double-blind, placebo-controlled, event-driven trial in 16 485 patients with moderate COPD who had or were at high risk of CVD. Here, we assessed the prespecified secondary endpoint of time to first on-treatment composite CVD event (CVD death, myocardial infarction, stroke, unstable angina or transient ischaemic attack (TIA)) by Cox regression and by clinician-reported CVD adverse events across the four groups: once-daily inhaled placebo (n=4111), long-acting beta
2 -agonist (vilanterol (VI) 25 µg; n=4118), corticosteroid (fluticasone furoate (FF) 100 µg; n=4135) and combination therapy (FF/VI; n=4121)., Results: Participants were predominantly middle-aged (mean 65 (SD 8) years) men (75%) with overt CVD (66%). The composite CVD endpoint occurred in 688 patients (first event: sudden death (35%), acute coronary syndrome (37%) and stroke or TIA (23%), and was not reduced in any treatment group versus placebo: VI (HR 0.99, 95% CI 0.80 to 1.22), FF (HR 0.90, 95% CI 0.72 to 1.11) and their combination (HR 0.93, 95% CI 0.75 to 1.14). Outcomes were similar among all subgroups. Adverse events, including palpitations and arrhythmias, did not differ by treatment., Conclusions: In patients with COPD with moderate airflow limitation and heightened CVD risk, treatment with inhaled VI, FF or their combination has an excellent safety profile and does not impact CVD outcomes., Trial Registration Number: NCT01313676., Competing Interests: Competing interests: RDB, PMAC, BRC, FJM, JV and DEN are external members of the SUMMIT Steering Committee. JAA, CC and JY are employed by GSK and are members of the SUMMIT Steering Committee. MAD and SM are members of the SUMMIT Clinical Endpoint Committee, and SR is a member of the SUMMIT Independent Data Monitoring Committee., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)- Published
- 2017
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191. Correction: Elevated plasma levels of cardiac troponin-I predict left ventricular systolic dysfunction in patients with myotonic dystrophy type 1: A multicentre cohort follow-up study.
- Author
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Hamilton MJ, Robb Y, Cumming S, Gregory H, Duncan A, Rahman M, McKeown A, McWilliam C, Dean J, Wilcox A, Farrugia ME, Cooper A, McGhie J, Adam B, Petty R, Longman C, Findlay I, Japp A, Monckton DG, and Denvir MA
- Abstract
[This corrects the article DOI: 10.1371/journal.pone.0174166.].
- Published
- 2017
- Full Text
- View/download PDF
192. Cardiomyocyte proliferation in zebrafish and mammals: lessons for human disease.
- Author
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Matrone G, Tucker CS, and Denvir MA
- Subjects
- Animals, Cardiomegaly drug therapy, Cardiomegaly metabolism, Drug Discovery, Heart drug effects, Heart embryology, Heart growth & development, Heart Injuries drug therapy, Heart Injuries metabolism, Humans, Hyperplasia drug therapy, Hyperplasia metabolism, Hyperplasia pathology, Myocytes, Cardiac metabolism, Signal Transduction, Zebrafish embryology, Zebrafish physiology, Cardiomegaly pathology, Cell Proliferation drug effects, Heart Injuries pathology, Myocytes, Cardiac cytology, Myocytes, Cardiac pathology
- Abstract
Cardiomyocytes proliferate profusely during early development and for a brief period after birth in mammals. Within a month after birth, this proliferative capability is dramatically reduced in mammals unlike lower vertebrates where it persists into adult life. The zebrafish, for example, retains the ability to regenerate the apex of the heart following resection by a mechanism predominantly driven by cardiomyocyte proliferation. Differences in proliferative capacity of cardiomyocytes in adulthood between mammals and lower vertebrates are closely liked to ontogenetic or phylogenetic factors. Elucidation of these factors has the potential to provide enormous benefits if they lead to the development of therapeutic strategies that facilitate cardiomyocyte proliferation. In this review, we highlight the differences between Mammalian and Zebrafish cardiomyocytes, which could explain at least in part the different proliferative capacities in these two species. We discuss the advantages of the zebrafish as a model of cardiomyocyte proliferation, particularly at the embryonic stage. We also identify a number of key molecular pathways with potential to reveal key steps in switching cardiomyocytes from a quiescent to a proliferative phenotype.
- Published
- 2017
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193. Elevated plasma levels of cardiac troponin-I predict left ventricular systolic dysfunction in patients with myotonic dystrophy type 1: A multicentre cohort follow-up study.
- Author
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Hamilton MJ, Robb Y, Cumming S, Gregory H, Duncan A, Rahman M, McKeown A, McWilliam C, Dean J, Wilcox A, Farrugia ME, Cooper A, McGhie J, Adam B, Petty R, Longman C, Findlay I, Japp A, Monckton DG, and Denvir MA
- Subjects
- Adult, Aged, Biomarkers blood, Echocardiography, Female, Follow-Up Studies, Humans, Male, Middle Aged, Myotonin-Protein Kinase genetics, Young Adult, Myocardium pathology, Myotonic Dystrophy pathology, Troponin I blood, Ventricular Dysfunction, Left blood, Ventricular Dysfunction, Left diagnosis
- Abstract
Objective: High sensitivity plasma cardiac troponin-I (cTnI) is emerging as a strong predictor of cardiac events in a variety of settings. We have explored its utility in patients with myotonic dystrophy type 1 (DM1)., Methods: 117 patients with DM1 were recruited from routine outpatient clinics across three health boards. A single measurement of cTnI was made using the ARCHITECT STAT Troponin I assay. Demographic, ECG, echocardiographic and other clinical data were obtained from electronic medical records. Follow up was for a mean of 23 months., Results: Fifty five females and 62 males (mean age 47.7 years) were included. Complete data were available for ECG in 107, echocardiography in 53. Muscle Impairment Rating Scale score was recorded for all patients. A highly significant excess (p = 0.0007) of DM1 patients presented with cTnI levels greater than the 99th centile of the range usually observed in the general population (9 patients; 7.6%). Three patients with elevated troponin were found to have left ventricular systolic dysfunction (LVSD), compared with four of those with normal range cTnI (33.3% versus 3.7%; p = 0.001). Sixty two patients had a cTnI level < 5ng/L, of whom only one had documented evidence of LVSD. Elevated cTnI was not predictive of severe conduction abnormalities on ECG, or presence of a cardiac device, nor did cTnI level correlate with muscle strength expressed by Muscle Impairment Rating Scale score., Conclusions: Plasma cTnI is highly elevated in some ambulatory patients with DM1 and shows promise as a tool to aid cardiac risk stratification, possibly by detecting myocardial involvement. Further studies with larger patient numbers are warranted to assess its utility in this setting.
- Published
- 2017
- Full Text
- View/download PDF
194. Cardiac GR and MR: From Development to Pathology.
- Author
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Richardson RV, Batchen EJ, Denvir MA, Gray GA, and Chapman KE
- Subjects
- Animals, Heart Diseases metabolism, Humans, Myocytes, Cardiac metabolism, Receptors, Glucocorticoid genetics, Receptors, Mineralocorticoid genetics, Signal Transduction physiology, Receptors, Glucocorticoid metabolism, Receptors, Mineralocorticoid metabolism
- Abstract
The efficacy of mineralocorticoid receptor (MR) antagonism in the treatment of certain patients with heart failure has highlighted the pivotal role of aldosterone and MR in heart disease. The glucocorticoid (GC) receptor (GR) is also expressed in heart, but the role of cardiac GR had received much less attention until recently. GR and MR are highly homologous in both structure and function, although not in cellular readout. Recent evidence in animal models has uncovered a tonic role for GC action via GR in cardiomyocytes in prevention of heart disease. Here, we review this evidence and the implications for a balance between GR and MR activation in the early life maturation of the heart and its subsequent health and disease., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2016
- Full Text
- View/download PDF
195. Palliative care needs in patients hospitalized with heart failure (PCHF) study: rationale and design.
- Author
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Campbell RT, Jackson CE, Wright A, Gardner RS, Ford I, Davidson PM, Denvir MA, Hogg KJ, Johnson MJ, Petrie MC, and McMurray JJ
- Abstract
Aims: The primary aim of this study is to provide data to inform the design of a randomized controlled clinical trial (RCT) of a palliative care (PC) intervention in heart failure (HF). We will identify an appropriate study population with a high prevalence of PC needs defined using quantifiable measures. We will also identify which components a specific and targeted PC intervention in HF should include and attempt to define the most relevant trial outcomes., Methods: An unselected, prospective, near-consecutive, cohort of patients admitted to hospital with acute decompensated HF will be enrolled over a 2-year period. All potential participants will be screened using B-type natriuretic peptide and echocardiography, and all those enrolled will be extensively characterized in terms of their HF status, comorbidity, and PC needs. Quantitative assessment of PC needs will include evaluation of general and disease-specific quality of life, mood, symptom burden, caregiver burden, and end of life care. Inpatient assessments will be performed and after discharge outpatient assessments will be carried out every 4 months for up to 2.5 years. Participants will be followed up for a minimum of 1 year for hospital admissions, and place and cause of death. Methods for identifying patients with HF with PC needs will be evaluated, and estimates of healthcare utilisation performed., Conclusion: By assessing the prevalence of these needs, describing how these needs change over time, and evaluating how best PC needs can be identified, we will provide the foundation for designing an RCT of a PC intervention in HF.
- Published
- 2015
- Full Text
- View/download PDF
196. The use of innovative methods designed to relieve social isolation in patients with chronic heart failure; volunteer befriending, forums and a newsletter.
- Author
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Peardon L, Yellowlees D, Pratt R, Reid J, O'Donnell M, Ness A, Chalmers C, Leslie SJ, and Denvir MA
- Subjects
- Communication, Friends, Humans, Interpersonal Relations, Program Development, State Medicine, United Kingdom, Volunteers, Heart Failure psychology, Social Isolation psychology, Social Support
- Abstract
Introduction: Social isolation in patients with chronic heart failure (CHF) is an adverse prognostic factor. This paper reports the creation of a supportive patient/carer network (Heart Failure Support Service), led by a voluntary sector/National Health Service (NHS) partnership which involved volunteer befriending, regular patient and carer forum and a newsletter., The Project: Over 3 years, 37 volunteers were 'befrienders' to over 50 individuals with CHF. A thorough training and matching process ensured that the first befriending visit was a positive experience. 100% of patients found the visits from the volunteer worthwhile and said they would recommend the service to other patients. Prior to the first patient-carer forum, 200 questionnaires were sent out with a 56% response rate, 44% of respondents believed that a forum and a newsletter would be valued. Over a period of 3 years, 12 quarterly meetings were held with an average attendance of 30-40 per meeting. The newsletter (current circulation >800 per quarter) contributed to self-management and encouraged communication between professionals and patients-carers., Conclusions: The Heart Failure Support Service (volunteers, forum and newsletter) created a supportive patient-carer network and represents a successful voluntary sector/NHS partnership., ((c) 2009 Elsevier B.V. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
197. Social deprivation and poor prognosis after cardiac surgery.
- Author
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Denvir MA and Zamvar V
- Subjects
- Heart Diseases mortality, Humans, Prognosis, Socioeconomic Factors, Cardiac Surgical Procedures mortality, Heart Diseases surgery
- Published
- 2009
- Full Text
- View/download PDF
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