Publications by authors named "Brendan Corcoran"

Background: TGFβ signaling appears to contribute to the pathogenesis of myxomatous mitral valve disease (MMVD) in both dogs and humans. However, little is known about the extent of the downstream signaling changes that will then affect cell phenotype and function in both species.

Objective: Identify changes in downstream signals in the TGFβ pathway in canine MMVD and examine the effects of antagonism of one significant signal (SMAD2 was selected).

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PI3K/AKT/mTOR signalling contributes to several cardiovascular disorders. The aim of this study was to examine the PI3K/AKT/mTOR pathway in myxomatous mitral valve disease (MMVD). Double-immunofluorescence examined expression of PI3K and TGF-β1 in canine valves.

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Arterial calcification is an important characteristic of cardiovascular disease. It has key parallels with skeletal mineralization; however, the underlying cellular mechanisms responsible are not fully understood. Mitochondrial dynamics regulate both bone and vascular function.

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Background And Purpose: Recent endovascular trials have spurred a paradigm shift toward routine use of CT perfusion (CTP) for decision-making in acute ischemic stroke. CTP use in the late window, however, remains under evaluation. Our objective was to assess the accuracy of CTP-predicted core in the late window.

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Vascular calcification is associated with aging, type 2 diabetes, and atherosclerosis, and increases the risk of cardiovascular morbidity and mortality. It is an active, highly regulated process that resembles physiological bone formation. It has previously been established that pharmacological doses of metformin alleviate arterial calcification through adenosine monophosphate-activated protein kinase (AMPK)-activated autophagy, however the specific pathway remains elusive.

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Purpose: To evaluate the percentage of misplaced medical support lines and tubes in deceased trauma patients using post-mortem computed tomography (PMCT).

Methods: Over a 9-year period, trauma patients who died at or soon after arrival in the emergency department were candidates for inclusion. Whole body CT was performed without contrast with support medical devices left in place.

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Mitral valve prolapse (MVP) due to myxomatous degeneration is one of the most important chronic degenerative cardiovascular diseases in people and dogs. It is a common cause of heart failure leading to significant morbidity and mortality in both species. Human MVP is usually classified into primary or non-syndromic, including Barlow's Disease (BD), fibro-elastic deficiency (FED) and Filamin-A mutation, and secondary or syndromic forms (typically familial), such as Marfan syndrome (MFS), Ehlers-Danlos syndrome, and Loeys-Dietz syndrome.

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Objectives: Recent endovascular trials have established the use of CT perfusion (CTP) in endovascular treatment selection for patients with large vessel occlusions (LVO). However, the relationship between CTP and collateral circulation is unclear in delayed time windows. We explored the relationship between CT Angiogram (CTA) collaterals and CTP parameters in delayed time windows (6-24 hours).

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Myxomatous mitral valve disease (MMVD) is the most common cardiac disease in dogs. It varies from dogs without clinical signs to those developing left-sided congestive heart failure, leading to death. Cavalier King Charles Spaniels (CKCSs) are particularly susceptible to MMVD.

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Background And Purpose: The Alberta Stroke Program Early Computed Tomography (CT) Score (ASPECTS) and CT perfusion (CTP) are commonly used to predict the ischemic core in acute ischemic strokes. CT angiography source images (CTA-SI) can also provide additional information to identify the extent of ischemia. Our objective was to investigate the correlation of noncontrast CT (NCCT) ASPECTS and CTA-SI ASPECTS with CTP core volumes.

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The maintenance of a healthy cardiovascular system requires expression of genes that contribute to essential biological activities and repression of those that are associated with functions likely to be detrimental to cardiovascular homeostasis. Vascular calcification is a major disruption to cardiovascular homeostasis, where tissues of the cardiovascular system undergo ectopic calcification and consequent dysfunction, but little is known about the expression of calcification genes in the healthy cardiovascular system. Large animal models are of increasing importance in cardiovascular disease research as they demonstrate more similar cardiovascular features (in terms of anatomy, physiology and size) to humans than do rodent species.

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Myxomatous mitral valve disease (MMVD) is the most common acquired canine cardiovascular disease and shares many similarities with human mitral valvulopathies. While transcriptomic datasets are available for the end-stage disease in both species, there is no information on how gene expression changes as the disease progresses, such that it cannot be stated with certainty if the changes seen in end-stage disease are casual or consequential. In contrast to humans, the disease in dogs can be more readily examined as it progresses, and this allows an opportunity for insight into disease pathogenesis relevant to both species.

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Myxomatous mitral valve disease (MMVD) is the single most important acquired cardiovascular disease of the dog. Much is known about the cellular changes and the contribution of activated myofibroblasts (valve interstitial cells (aVICs) to the valve extra-cellular matrix remodelling characteristic of the disease. However, little is known on how aVIC survival might contribute to disease pathogenesis.

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The utility of cells cultured from the mitral valve as models of myxomatous diseases needs to be properly validated. In this study valve interstitial cells (VICs) and valve endothelial cells (VECs) were cultured from normal and diseased canine mitral valves in 2% (v/v) or 10% FBS media, in the presence of TGFβ1, 2 and 3, the TGFβ RI kinase inhibitor SB431542 and TGFβ neutralising antibodies, 5HT and the 5HT2RB antagonist LY272015. Cultures were examined by morphology, transcriptomic profiling, protein expression of the cell specific markers αSMA and SM22α (VICs), and CD31 (VECs), deposition of proteoglycans (PG), the PG versican, and the TGFβs themselves.

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Calcific aortic valve disease (CAVD) is characterized by the progressive thickening of the aortic valve leaflets. It is a condition frequently found in the elderly and end-stage renal disease (ESRD) patients, who commonly suffer from hyperphosphatemia and hypercalcemia. At present, there are no medication therapies that can stop its progression.

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Calcific aortic valve disease (CAVD) involves progressive valve leaflet thickening and severe calcification, impairing leaflet motion. The in vitro calcification of primary rat, human, porcine and bovine aortic valve interstitial cells (VICs) is commonly employed to investigate CAVD mechanisms. However, to date, no published studies have utilised cell lines to investigate this process.

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Myxomatous mitral valve disease is the single most important mitral valve disease in both dogs and humans. In the case of the dog it is ubiquitous, such that all aged dogs will have some evidence of the disease, and for humans it is known as Barlow's disease and affects up to 3% of the population, with an expected increase in prevalence as the population ages. Disease in the two species show many similarities and while both have the classic myxomatous degeneration only in humans is there extensive fibrosis.

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Idiopathic pulmonary fibrosis is an interstitial lung disease of unknown etiology resulting in progressive interstitial fibrosis, with a known predilection in West Highland white terriers. In humans, computed tomography (CT) is a standard method for providing diagnostic and prognostic information, and plays a major role in the idiopathic pulmonary fibrosis staging process. Objectives of this retrospective, analytical, cross-sectional study were to establish descriptive criteria for reporting CT findings and test correlations among CT, clinical findings and survival time in West Highland white terriers with idiopathic pulmonary fibrosis.

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Epithelial to mesenchymal transition (EMT) and the cardiovascular equivalent, endothelial to mesenchymal transition (EndoMT), contribute to a range of chronic degenerative diseases and cancer metastasis. Chronic valvulopathies exhibit some features of EndoMT and activation of developmental signalling pathways, such as osteogenesis and chondrogenesis, expression of cell differentiation markers, basement membrane damage and endothelial transformation. The aim of the present study was to investigate the potential role of developmental mechanisms in canine myxomatous mitral valve disease (MMVD) using a combination of transcriptomic array technology, RT-PCR and immunohistochemistry.

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Cleavage of the thioether bond of S-D-ribosyl-L-homocysteine (SRH) by the enzyme S-ribosylhomocysteinase (LuxS) serves as the final biosynthetic step in the generation of the quorum sensing autoinducer AI-2 by bacteria. Herein, a revised chemical synthesis of SRH is presented at convenient scale and purity for in vitro studies of LuxS. Potassium bis(trimethylsilyl)amide (KHMDS) is identified as a judicious base for the formation of the thioether of the target compound from readily-accessible precursors: a thiol nucleophile derived from l-homocystine and a sulfonate-activated d-ribosyl electrophile.

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Non-primate hepacivirus (NPHV), equine pegivirus (EPgV) and Theiler's disease associated virus (TDAV) are newly discovered members of two genera in the Flaviviridae family, Hepacivirus and Pegivirus respectively, that include human hepatitis C virus (HCV) and human pegivirus (HPgV). To investigate their epidemiology, persistence and clinical features of infection, large cohorts of horses and other mammalian species were screened for NPHV, EPgV and TDAV viraemia and for past exposure through serological assays for NPHV and EPgV-specific antibodies. NPHV antibodies were detected in 43% of 328 horses screened for antibodies to NS3 and core antibodies, of which three were viraemic by PCR.

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Purpose: Progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) is associated with accumulated genomic instability. Current risk stratification of BE for EAC relies on histological classification and grade of dysplasia. However, histology alone cannot assess the risk of patients with inconsistent or non-dysplastic BE histology.

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Background: The clinical outcome of idiopathic pulmonary fibrosis (IPF) is poor, with a 50% survival rate at 3 years. Furthermore, current treatments provide little amelioration of symptoms. Despite significant advances in understanding the clinical features and pathobiology of IPF, further advances have been hampered by a lack of suitable animal models of the disease.

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