Combustion-derived nanoparticles (diameter ≤ 100 nm) present in air pollution are thought to be associated with the onset of platelet-driven thrombotic events such as myocardial infarction. In addition, the emergence of nanotechnology has led to increased human exposure to engineered nanoscale structures. My first aim was to establish whether engineered nanoparticles could influence platelet function and whether this was dictated by their size and surface charge. The second aim was to evaluate if combustion-derived nanoparticles could modulate platelet aggregation in-vivo and determine the underlying mechanisms. 50 nm and 100 nm carboxyl, amine and unmodified model engineered polystyrene nanoparticles as well as diesel exhaust particles (DEP) and carbon black (CB) were intratracheal (i.t.) or intravenously (i.v.) administered into mice and in-vitro and in-vivo platelet aggregation, markers of pulmonary and systemic inflammation and plasma nitrate levels were measured. All model engineered nanoparticles induced concentration-dependent platelet aggregation which was inhibited by conventional platelet inhibitors and endogenous vascular regulators. In contrast, amine-modified 50 nm particles enhanced agonist-induced platelet aggregation in-vitro and in-vivo. DEP increased agonist-induced platelet aggregation in-vivo that was not associated with inflammation or altered plasma nitrite levels. In contrast, CB did not increase platelet aggregation but did appear to initiate inflammation. All nanoparticles investigated induced platelet aggregation with potencies and mechanisms that were dependent upon a distinct combination of size and surface chemistry. 50 nm cationic particles may present the largest risk to human health by exacerbating thrombotic events, as they can enhance the effects of platelet agonists at low concentrations. Additionally, exposure to DEP can enhance platelet aggregation in-vivo suggesting that the thrombotic incidents triggered by acute exposure to particulate pollutants may be platelet driven although the underlying mechanism does not appear to involve systemic inflammation or alterations in NO bioavailability.

Background and Aim: There is a subset of conditions - Ambulatory Care Sensitive Conditions (ACSCs) - for which emergency admission into secondary care is thought to be avoidable through better primary care. This research aims to: develop a model to predict ACSC-admission rates by GP practice; determine whether ACSC-admission rates are a viable performance metric; identify how much inefficiency exists among practices; and identify interventions that reduce ACSC admissions. Methods: The work uses routine administrative datasets (e.g. HES and Attribution Dataset), linked at the level of the general practice, for all practices in England providing NHS care. It uses techniques including multiple linear regression, corrected ordinary least squares, stochastic frontier analysis and propensity score matching to test its hypotheses. Results: Adjusting for population characteristics (e.g. deprivation and disease prevalence), some QOF indicators and GP patient survey results were associated with lower admissions rates. Aggregating admission rates across more practices improved the accuracy of predicted rates; at average CCG size (33 practices), the 95% confidence interval is ± 8.6%. If all GP practices in England became as efficient as those that were top performing, allowing for practices' population characteristics, there would be a 20.4% reduction in the number of ACSC admissions, based on 2010/11 data. Two interventions were found to lower admission rates. Patient advice and liaison service led to 5.9% fewer admissions for diabetes and 6.5% fewer admissions for hypertension. Information and support for diabetes led to 4.1% fewer admissions for diabetes. Conclusions: Improving the efficiency of practices to best-practice levels would mean 242,143 fewer admissions per year - a £411m annual saving - however a metric for judging practices' quality based on ACSC-admission rates would need a degree of leniency. Interventions can be found that reduce ACSC admissions and commissioners should consider expanding them. ACSC-impact assessments should be carried out before commissioning such interventions.

The work in this thesis sought to examine the effects of enhancing cardiac gap junction coupling using the pharmacological agent Rotigaptide in clinically applicable models of acute myocardial infarction. Specifically, the studies in this thesis investigated the effect of Rotigaptide on ventricular arrhythmogenesis and structural remodelling of the reperfused substrate, with particular emphasis on the development, application and histological validation of diffusion tensor magnetic resonance imagine (DTI) as a novel imaging modality to describe and quantify structural remodelling post-infarction. An ex vivo rat model of acute regional ischaemia-reperfusion was characterised and used to study the effect of Rotigaptide on ventricular arrhythmogenesis during acute ischaemia and reperfusion. Arrhythmias occurred during ischaemia in a monomodal distribution with a peak incidence between 12-15 minutes after ischaemia. The incidence of reperfusion arrhythmias was dependent on the preceding duration of ischaemia with a progressive reduction as ischaemic time extended from 15 to 60 minutes. Rotigaptide pre-treatment afforded a significant reduction in ischaemia-induced arrhythmias compared to administration at the onset of ischaemia or at the time of reperfusion. An in vivo rat model of infarction-reperfusion, mimicking clinical reperfusion in the setting of acute MI was characterised and Rotigaptide administered prior to reperfusion and for a week post-MI. At four-weeks post-MI animals were studied with 6-lead ECG, ambulatory telemetry, programmed electrical simulation (PES), optical mapping, DTI and histology. Rotigaptide reduced the susceptibility to arrhythmias induced by PES and partially restored DTI-derived indices of tissue disruption in infarcted myocardium.

Liver disease is a prevalent clinical challenge caused by a variety of factors including viral infections and xenobiotic overdose. Improving our mechanistic understanding of disease development will lead to an improved stratification of patients and ultimately a better prognosis. This thesis addresses the role of metabonomics in providing insight into a variety of preclinical models and a clinical study. The metabolic phenotype of preclinical models of paracetamol (APAP) and methotrexate (MTX) toxicity were characterised, together with the study of clinical samples from decompensated cirrhosis, acute on chronic liver failure (ACLF) and acute liver failure (ALF) patients. A comparative metabonomic approach was applied to study the metabolic consequences following administration of APAP and its non-hepatotoxic isomer; N-acetyl-m-aminophenol (AMAP), in mice. The analysis revealed an APAP-induced hepatotoxicity through mitochondrial dysfunction which was characterized by an upregulation of glycolysis as well as the inhibition of beta-oxidation and the Krebs cycle. The metabolic and toxic effects of MTX were investigated in healthy rats and in a model of non-alcoholic steatohepatitis (NASH; as modelled by the methionine choline deficient diet). MTX was shown to have an enhanced toxicity in the context of NASH, which was associated with unique metabolic changes. The clinical work revealed that the serum metabolic phenotypes of clinical decompensated cirrhosis, ACLF and ALF patients were also each characterized by unique metabolic perturbations. The ALF phenotype was associated with the most metabolic changes and consisted of markers of oxidative and energetic stress, as well as markers of amino acid metabolism dysfunction. Subsequently, the novel serum metabolic profiling of the hepatic vein, hepatic portal vein and peripheral artery of patients during liver transplantation aimed to characterize the hepatic disease microenvironment, which was discovered to mainly consist of a perturbed amino acid metabolism.

Atrial fibrillation (AF) is a major health problem, affecting 1-2% of the population. AF reduces quality of life (QoL) and increases morbidity and mortality. Catheter ablation (CA) is the most efficacious means of restoring sinus rhythm but is not always successful and is occasionally associated with serious complications. Several questions are currently unanswered. True procedural effectiveness, particularly long-term, remains uncertain, especially in more advanced disease. The best technique for achieving success remains an issue of considerable debate and as yet, few, if any, means exist to predict when acute electrical success will translate into sustained clinical benefit. CA is indicated for symptomatic relief but QoL, both as a treatment outcome and as a guide to patient selection, has generally been overlooked in the published literature. Finally, although the maxim, 'First, do no harm' may often be ascribed erroneously to Hippocrates, it remains a central tenet of medical practice. However, little previous research has focussed on improving the safety of CA. I have attempted to tackle these issues from a number of angles. I have performed a comprehensive literature review and a retrospective analysis of ablation outcomes at Liverpool Heart and Chest Hospital, the largest and longest such data from the UK, to ascertain a comprehensive, up-to-date assessment of practice. In an effort to improve procedural success, I carried out a multicentre randomised controlled trial testing two ablation strategies. A sub-study tests the hypothesis that clinical outcomes can be predicted by a novel measure of effective ablation. Two further studies aim to improve safety, through use of ultrasound to guide venous access, and to better understand QoL in AF - a theme throughout the thesis - which may help improve selection of appropriate patients for CA. Together, I hope these studies will help physicians improve the outcomes of CA for their patients.

Rectal cancer is a common and complex form of colorectal malignancy which is the second largest cause of cancer death in the United Kingdom. The need for an accurate method of staging as a guide to selecting treatment has become increasingly important with the recent advances in options for preoperative therapy. It is now clearly understood that there are a number of prognostic features that can predict a poor outlook. These include; local tumour extent, involved circumferential resection margin, involved lymph nodes and extramural venous invasion. Traditionally these factors have been noted on histopathology of the resected specimen by which time the opportunity to institute preoperative therapy has been lost. Identification of these factors prior to surgery would be of paramount importance in potentially improving the outcome for these selected patients. MRI has now been shown to be proficient at identifying many of these features. The MERCURY study (Magnetic Resonance Imaging and Rectal Cancer European Equivalence Study) recruited 679 patients from 11 different centres, prior to surgery (in 2002-2003) and was able to demonstrate the ability of MRI to predict margin involvement and local extent of tumour invasion. Data has been collected on the 5 year outcome of 374 patients consenting to follow up in the MERCURY study. This thesis explores the relationship of the distance to the circumferential resection margin, the prognostic significance of predicted involvement of the margin and the ability of MRI to identify patients with early tumours, good prognosis tumours and those with poor prognostic features. The aim is to investigate the significance of these factors in predicting the long term outcome of these patients.

Background: Surveillance has been described as an essential component of an effective infection prevention and control programme. With increasing concerns over the rising levels of antimicrobial resistance there has been emphasis on the requirement to improve infectious disease surveillance and outbreak detection. The availability of healthcare information in electronic formats provides an opportunity to perform surveillance and outbreak detection at the hospital level. Aim: To determine if data available from national and local microbiology surveillance systems can be utilised for outbreak detection of infectious diseases within the acute healthcare setting. Methods: A critical analysis of a national microbiological surveillance system is performed prior to the application of methods for automated outbreak detection. At the local level, an epidemiological analysis is performed to ascertain the levels of antimicrobial resistance and identify trends before carrying out outbreak detection for multidrug-resistant organisms (MDRO). Several methods for outbreak detection are investigated, including exceedance detection algorithms, cumulative sum methods and variable life adjusted display charts. Results: Results from a comprehensive systematic review found that the employment of systems utilising electronic data sources for healthcare-associated infection surveillance is feasible. Evaluation of a national microbiological surveillance system identified several issues with using data reported through a voluntary system for outbreak detection at the hospital level. After identification of a hospital laboratory exhibiting consistent and timely reporting it became apparent that outbreak detection methods could be applied to data available through the national system. At the local level, MDRO were identified through the application of algorithms to electronically stored microbiology data. The selected outbreak detection methods were successfully applied to local level data, identifying several potential MDRO outbreak situations. Conclusions: This thesis demonstrates that there is potential for the implementation of automated systems for hospital level outbreak detection using both national and local microbiological data sources.

Asthma is a chronic inflammatory disease of the airways, resulting in significant morbidity and premature deaths. Rhinoviruses, agents of the common cold, have been identified as the most frequent viruses inducing asthma exacerbations. However the mechanisms involved in this process, especially in moderate-to-severe asthmatics, are not clear. IL-17, a protein secreted by Th17 and IL-17+γδ T cells, is found to be up-regulated in asthmatics and correlates with severity of disease. Observations from a clinical study of rhinovirus infection showed increased induction of IL-17 in nasal lavage fluid from asthmatics following experimental rhinovirus infection compared to healthy controls. Using mouse models, this thesis addresses the interactions of rhinovirus with IL-17 in the context of allergic airways disease. Primary infection of C57BL/6 mice did not induce IL-17 responses as seen in human subjects; this may be explained by the apparent lack of induction of IL-23 following primary infection in mice. Supplementation of rhinovirus infection with recombinant IL-17 showed significant, selective increases in neutrophil chemokines with subsequent increases in both neutrophil recruitment and activation, as defined by myeloperoxidase activity. In an existing Th2-driven model of allergic airways disease, rhinovirus was seen to selectively expand Th2 responses while not increasing allergen-induced Th17, IL-17+γδ T cells or IL-17. However, rhinovirus infection in a Th17-driven model of allergic airways disease showed a significant increase of neutrophil numbers with a concomitant increase in airway hyperresponsiveness. This work augments existing knowledge on rhinovirus exacerbation of Th2-mediated asthma with the interactions between Th17 and rhinovirus, which may play a significant role in moderate-to-severe asthma exacerbations. This supports current research on therapeutic targeting of the IL-17 pathway in asthmatics.

Cardiac hypertrophy is a growth response elicited in the heart by intrinsic and extrinsic stimuli in pathological as well as physiological conditions. The insulin-like growth factor-1 (IGF-1) propeptides regulate cardiac hypertrophy during normal development, although their role during pathological hypertrophy has yet to be explored. Previous data from our laboratory has shown that the locally acting propeptide IGF-1Ea inhibited angiotensin-induced pathological hypertrophy in vitro and more importantly regulated cardiac physiological growth in vivo. To investigate the specific role of IGF-1Ea in cardiac pathological growth response, I mimicked a clinical-like scenario in an animal model by inducing cardiac workload with the beta-adrenergic agonist isoproterenol and by cell-mediated delivery of IGF-1Ea and IGF-1 mature protein into the myocardial wall of immunodepleted mice. I observed that IGF-1Ea inhibited isoproterenol-induced increase of heart weight-to-body weight (HW/BW) ratio compared to IGF-1 treated mice. In parallel, isoproterenol-mediated increase of cardiomyocytes cross-sectional area was inhibited by IGF-1Ea, but not by IGF-1 mature protein. Importantly, in vivo magnetic resonance imaging (MRI) showed that only IGF-1Ea maintained end-diastolic volume, stroke volume, left ventricle mass and left ventricle weight-to-body weight ratio similar to control levels. In conclusion, these in vivo data indicate that IGF-1Ea controls workload-induced maladaptive cardiac growth compared to IGF-1 mature protein and suggest further investigations into the role of IGF-1 propeptides in modulating the balance between physiological versus pathological growth response. The outcome will be relevant for future clinical interventions to prevent degenerating growth responses in patients with cardiovascular disease.

With previous reports indicating changes in mortality, risk factors and management of primary liver cancer (PLC), evaluation of current trends in the incidence and mortality rates was indicated. Late diagnosis has been implicated to be a major contributor to the high fatality rates of PLC. This work aimed at: • studying trends of PLC by subcategories globally in general, and in England and Wales, in particular; • investigating liver-related morbidities of HIV infected patients in an African setting; and • discovering urinary biomarkers of hepatocellular carcinoma. The World Health Organisation (WHO) and Small Area Health Statistics Unit (SAHSU) databases were interrogated respectively, in order to achieve the first aim. The second aim was achieved through utilisation of databases of an African-based HIV treatment programme- AIDS Prevention Initiative in Nigeria (APIN), located in Jos, Nigeria. The European Union-funded Prevention of Liver Fibrosis and Cancer in Africa (PROLIFICA) case-control study in three West African countries was the platform through which urinary metabolic profiling was accomplished. Proton nuclear magnetic resonance spectroscopy (NMR) and parallel ultra-performance liquid chromatography mass spectrometry (UPLC-MS) were used for biomarker discovery studies. Mortality rates of intrahepatic bile duct carcinoma (IHBD) increased in all countries that were studied. Misclassification of hilar cholangiocarcinoma accounted for only a small increase in the rate of IHBD in England and Wales. With over 90% screening rate for viral hepatitides, the rates of hepatitis B (HBV), hepatitis C (HCV) and HBV/HCV in HIV-infected patients in the APIN programme were 17.8%, 11.3% and 2.5% respectively. There was attenuated immune response as well as significantly lower survival observed in HBV/HIV co-infection, relative to HIV mono-infected patients (p=0.0097). Whereas single urinary metabolites, including acetylcarnitine, N-acetylglutamate, betaine aldehyde, 3'-sialyllactose, methionine among others possessed high discriminatory power to diagnose HCC, a combination of three metabolites: 3'-sialyllactose, methionine and 9-decenoylcarnitine significantly outperformed serum alpha-fetoprotein (AFP) in the diagnosis of HCC in a cirrhosis population (area under the receiver operating characteristic curve; [urinary panel= 0.96] compared to [AFP = 0.64]). This work informs a critical assessment of current control strategies in the prevention of HCC, and potentially assists in the development of more affordable means of early detection of PLC for most affected regions of the world.