Mutations of the WFS1 gene are responsible for most cases of Wolfram syndrome (WS), a rare, recessively inherited neurodegenerative disorder characterised by juvenile-onset non-autoimmune diabetes mellitus and optic atrophy. Variants of WFS1 are also associated with non-syndromic hearing loss and type-2 diabetes. Understanding the function of the WFS1 protein-product wolframin, would enable developments in targeted therapy for WS patients and important insights to its possible contribution to type-2 diabetes pathogenesis. This study was aimed at expanding the spectrum of WS-associated genetic mutations and clinical data, and investigating the molecular mechanisms responsible for phenotypic variation associated with WFS1-mutation. The mutational and phenotypic spectrum of WS is broadened by our report of novel WFS1 mutations and a case of WFS2-associated WS. New perspectives on the molecular mechanisms linking mutation to disease manifestation are also taken by characterisation of representative WFS1 mutations specific to phenotype, identification of potentially novel WFS1 interacting partners, and the first evidence linking WFS1 with the exocrine pancreas. Our data suggests that some WFS1-mutations may allow residual protein function and these findings lay the groundwork for future functional investigation of mutated wolframin to explore this hypothesis further.

Chronic systemic immunosuppression in pancreatic islet transplantation restricts its clinical application. This study aims to explore the potential of cell-mediated immune-modulation as an alternative to conventional immunosuppressive regimens; specifically investigating the innate immunosuppressive properties of human amniotic epithelial cells (AEC). Cell constructs composed of human islets and AEC (islet:AEC) were bio-engineered in rotational culture. Insulin secretory capacity and immuno-modulatory potential were characterised using appropriate in vitro assays. Fluorescence immunocytochemistry and multiplex arrays was used to identify putative mediators of the immunosuppressive response in isolated AEC monocultures. Islets and islet:AEC constructs demonstrated sustained, physiologically-appropriate insulin secretion. Resting peripheral blood mononuclear cells (PBMC) were activated on exposure to human islets but this response was significantly (p<0.05) attenuated in islet:AEC constructs. Phytohaemagglutinin (5\( \mu \)g/ml)-induced PBMC proliferation was sustained on contact with unmodified islets but abrogated in AEC and islet:AEC constructs. CD4+ and CD8+ T-cell proliferation was responsive to AEC; their in vitro expansion both in response to CD3/CD28 activation and contact with human islets being suppressed by the presence of AEC. Transplanted islets may thus benefit from an immune-privilege status conferred on them as a consequence of their close proximity to human AEC. Such an approach may diminish the requirement for generalised systemic immunosuppression in islet transplantation.

The natural angiogenic response of the vasculature to cardiovascular disease has been shown, at least in part, to involve circulating endothelial progenitor cells (EPCs). However, the native response is often insufficient to restore vascularity without additional intervention. In this study the angiogenic activity of EPCs, demonstrated by in vitro tubule formation, confirmed the suggested potential of EPCs to be used therapeutically. However, as EPCs are found in limited circulating numbers, embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) were also investigated as sources of donor EPCs for transplantation. Here ESCs, but not iPSCs, were shown to generate cells with a genetic and proteomic profile, as well as an angiogenic potential, identical to natural EPCs. Using an in vivo mouse model of hindlimb ischemia, this investigation illustrated the preferential binding of transplanted EPCs at sites of angiogenic stimulation, and revealed the importance of platelets in the recruitment of circulating EPCs. In particular, using in vitro aggregation and flow-based adhesion assays, the adhesion molecule P-selectin was shown to play a significant role in this recruitment mechanism. In conclusion, this study has demonstrated that EPC transplantation has abundant potential for development into a viable and efficiacious therapeutic angiogenic treatment.

The use of memory strategies can promote independence in people who have an acquired brain injury but people often do not take readily to using such strategies. Certain demographic variables have been associated with the use of memory strategies these variables cannot be changed through therapeutic interventions. The aim of this thesis is to explore variables that may be modifiable through rehabilitation e.g. health beliefs and perceptions of aids, to see whether they help us understand factors influencing the uptake of memory strategies. The thesis consists of three studies. The first uses Interpretative Phenomenological Analysis to explore how people feel about using memory strategies. The second is a cross sectional questionnaire design exploring the predictive power of variables identified in the first study to predict the use of strategies together with demographic variables. The third is a single case study utilising findings from the first two studies to help an individual use a mobile phone and Google calendar as a memory aid. A key factor in the use of memory compensations is the need to ‘fit’ the aid to an individual’s lifestyle. Consequently, there is greater optimism for those who may otherwise be regarded as unlikely to use aids.

Deaf individuals have higher prevalence of mental health problems but are under-represented within mental health services. Despite emerging specialist provisions, utilisation remains poor. Yet little research has considered why this is. Therefore, a literature review and an empirical paper aimed to explore deaf people's mental health service experiences and highlight factors associated with help seeking behaviour. A systematic literature search was completed identifying nineteen studies for review. Themes emerged around deaf clients' mental health service experiences, covering accessibility, experiences of professional, and communication. Similarly, themes promoting help seeking covered integrated specialist services, signing professionals and alternative communication. The review highlighted that literature exploring deaf people's views towards mental health service experiences were lacking alongside communication breakdown being a central theme. 186 deaf children (aged 11-19) from UK specialist schools, covering two schooling dimensions (Oral-Deaf and Total Communication), were surveyed across various constructs mapped against the Health Belief Model. A thirteen percent variance in children's help-seeking intentions was explained by model variables, with outcome expectancy and self-efficacy being key to help-seeking intentions. Specific preferences for deaf/signing professionals and specialist services were unfounded. Help-seeking intentions were positively skewed given the specialist environment and easy access to mental health provision provided in these settings.

This study explores the learning journey of Post-Graduate Certificate in Education (PGCE) healthcare professional students who engaged with enquiry based learning (EBL). The methodology is a case study based on group interviews. Six groups totalling 59 students were interviewed to ascertain their experience of EBL, their conceptions of learning within a community of practice, transformative influences and emerging leadership qualities. The findings show EBL is a holistic learning experience that enables epistemic development which has features of threshold concepts, yet it is a process. The community of practice is fundamental to the process and engenders feelings of responsibility for others’ learning. The transformative component of EBL enables an ontological shift and the overall experience enables the development of leadership qualities, most notably, self-confidence, self-identity and self-belief. This study captures the students’ epistemic and ontological development through engagement with EBL. It argues the literature around threshold concepts should explore integrating student-centred pedagogy into threshold concepts rather than viewing it as a separate entity to enable PGCE students to develop leadership qualities. It utilises the proposed threshold process within a framework that outlines the preparation and practice of educational leaders in healthcare which embraces exposure to, engagement with and enactment of leadership.

Factors contributing towards falls in older age during overground walking have been widely studied. Stepping behaviour, balance and head posture control during stair negotiation in young adults (YA) and older adults with either lower (LROA) or higher (HROA) risk of falling during midstair negotiation have not been investigated. The aims of the thesis were threefold. Firstly, age-related changes in gaze behaviour were investigated. The main finding was that older adults fixate stair edges for longer than YA. Secondly, the effect of manipulating visual information on stepping parameters and balance control was compared between YA, LROA and HROA. For stair ascent, stepping and balance control was preserved in LROA and HROA and highlighted stair edges led to increased foot clearance in all groups. For stair descent, HROA demonstrated smaller foot clearance than LROA and highlighted stair edges improved balance in LROA and HROA. Thirdly, head posture was studied in YA, LROA and HROA. Compared to walking, LROA and HROA demonstrated more variable head posture than YA. Overall the findings suggest that adults use visual and probably proprioceptive information about stair edge locations to negotiate stairs and HROA benefited from highlighted stair edges. HROA should be included in future stair negotiation studies.

Perhexiline is an anti-anginal drug that is thought to shift myocardial metabolism from \(\beta\)-oxidation of fatty acids to glucose utilisation. An associated improvement in energy efficiency may be beneficial in ischaemia-reperfusion as an adjunct to established techniques for myocardial protection during cardiac surgery. In this thesis, I conduct a prospective double-blind randomised placebo-controlled trial of oral perhexiline in patients undergoing coronary artery surgery, obtaining samples of serum, right atrium and left ventricle. I measure the concentration of perhexiline using high performance liquid chromatography and find that although highly concentrated in the heart, it may not have reached steady-state in the ventricular myocardium. I perform enzymatic colourimetry and ultra-high resolution mass spectrometry to detect changes in carbohydrate and lipid metabolism; however, the myocardial metabolic profiles of patients on perhexiline are indistinguishable from controls. On analysing the results of the clinical trial, I find no improvement in the primary endpoint, the incidence of a low cardiac output episode, or any secondary outcomes. I conclude that preoperative oral perhexiline does not improve clinical markers of myocardial protection and despite significant accumulation in the myocardium, it has no significant effect on the measurable metabolic profile of the heart at the time of surgery.

State-of-the-art imaging equipment has increased clinician's ability to make non-invasive diagnoses of coronary heart disease (CHD); however, high volumes of imaging data make manual abnormality detection cumbersome in practice. In addition, the interpretation of CTA heavily relies upon the previous knowledge of the clinician. These limitations have driven an intense research in the context of automated solutions for fast, reliable and accurate diagnosis. Accordingly, in this thesis, we present an automated framework for detection, localization and quantification of the non-calcified coronary plaques in cardiac computed tomography angiography (CTA). The first contribution of the thesis is a coronary segmentation algorithm that is adaptive to the contrast agent and employs a hybrid energy incorporating local and global image statistics in a segmentation framework using partial differential equations (PDEs). Accordingly, we illustrated with the help of experimental evidence that a volume-specific intensity threshold leads to an improved segmentation in CTA. In the subsequent step, we employed a hybrid region-based energy for improved segmentation in CTA imagery. The hybrid energy couples an intensity-based local term with an efficient discontinuity-based global model of the image for optimal segmentation. The proposed method is less sensitive to the local optima problem and helps in reducing false positives, as well as it allows a certain degree of freedom for the initialization. Moreover, we employed an auto-correction feature for improved segmentation, as an auto-corrected mask captures the emerging peripheries of the coronary tree during the curve evolution. The effectiveness of the proposed model is demonstrated with the help of both qualitative and quantitative results, with a mean accuracy of 80% across the CTA dataset. The capability to address the variations in initial mask and localization radii simultaneously, makes our algorithm a feasible choice for coronary segmentation. The second contribution of the thesis is an automatic approach to analyse the segmented coronary tree for the presence of non-calcified plaques. The specific focus of this work is detection of non-calcified plaques in CTA, as intensity overlap between blood, fat and non-calcified plaques make the detection challenging. Non-calcified plaques are identified based on mean radial profiles that average the image intensities in concentric rings around the vessel centreline. Subsequently, an SVM classifier is applied to differentiate the abnormal coronary segments from normal ones. A total of 32 CTA volumes have been analysed and a detection accuracy of 88.4% with respect to the manual expert has been achieved. For plaque-affected segments, we further proposed a derivative-based method to localize the position and length of the plaque inside the segment. The plaque localization accuracy has been around 83.2%. Moreover, the proposed model has been tested on three different CTA datasets and has produced consistent results, demonstrating its reproducibility for generic CTA data. The final contribution of the thesis is a method to segment and quantify the non-calcified plaque. After evaluating the vessel wall thickness, posterior probability based voxel classification has been performed to quantify the lumen and plaque, respectively. Both qualitative and quantitative results demonstrate that the proposed model shows a good agreement with three independent experts. To optimize the processing time, we employed sparse field method in a level-set based active contour evolution.

Background. The growing population of migrants (including sub-Saharan Africans) in the United Kingdom poses challenges to British general practice. First, migrants tend to seek health care at times of crisis rather than for preventive measures. This is despite being at increased risk of certain chronic conditions compared with the indigenous population. For sub-Saharan Africans this includes hypertension-related diseases and some cancers. Little has been published about Africans’ awareness of this risk or their knowledge of associated causative factors. Second, discordant health beliefs and healthcare expectations between migrants and doctors in the UK have been found to undermine trust during consultations with general practitioners and to lead to poor patient satisfaction. Little is known about the health behaviours of African migrants whose expectations are not met by primary care in the UK. A related area where health beliefs and practices differ between African migrants and their GPs is in the use of traditional medicines. A final challenge lies in considering the wider issues that GPs must address when consulting with migrant patients, including time pressures, organisational factors and the complex nature of problems presented by migrant patients. These issues are the focus of this study. Aims. To examine African migrants’ perceptions of chronic disease and their experience of seeking primary health care in the UK. To explore the impact upon GPs of caring for migrants. Objectives. To explore: 1) perceptions of chronic disease risk facing African migrants and their underlying explanatory models; 2) experiences of consultations about antibiotic prescriptions; 3) traditional African medicine use in the UK; and (4) to consider the effect of workload and work patterns on GP consultations with migrants. Design. In-depth interviews were conducted with 19 Africans from French- or Swahili- speaking countries, one African key informant and 13 GPs working with migrants. African participant recruitment was from community organisations and GPs were approached via an informal network of doctors. Interviews were transcribed and ten were translated by the principal investigator (three Swahili and seven French). Data analysis was undertaken following the approach of applied thematic analysis using the Nvivo software package. Data collection and analyses were underpinned by the following theoretical frameworks: Kleinman’s explanatory models of illness and of cultural health care systems and Lipsky’s street-level bureaucracy. Results. Narratives suggested low awareness of chronic disease risk amongst Africans. Infectious diseases were considered the dominant health threat for African migrants, mainly HIV but also tuberculosis and ‘flu’. Chronic diseases were sometimes described by Africans as contagious. Explanatory models of chronic disease included bodily/dietary imbalance, stress/exertion, heredity/predisposition and food contamination. Cancer was feared but not considered a major threat. Cancer was considered more common in Europe than in Africa and was attributed by Africans to chemical contamination from fertilizers, food preservatives and industrial pollution. Evidence cited for these chemicals was rapid livestock/vegetable production, large size of farmed products (e.g. fish), softness of meat and flavourless food. Chemicals were reported to circulate silently inside the body and cancer to develop in the part where they deposit, sometimes years later. Africans’ belief in infective explanations of disease extended to minor illnesses and was manifested in an expectation of antibiotics from GPs for problems such as a sore throat. This arose from participants’ experience in Africa, witnessing life-threatening infectious diseases and experience of unregulated access to antibiotics. Africans described various alternative measures to fulfil their unmet expectations, including approaching other National Health Service doctors, importing medication, and using private healthcare services in London, francophone Europe and east Africa. A further option was the use of traditional African medicine, reported by one quarter of African participants. Traditional African herbal medicine use was based upon a perception of its purity and natural origin in African soil and a deep belief in its efficacy. Consulting traditional African healers in the UK was reported to be undertaken in secret. Some GPs and Africans described consultations in terms of pressure, processing and conflict. Migrants were reported to present with complex health problems that were frequently compounded by language barriers. GPs described a need to remain in control of consultations and this included some use of personal discretion to render their tasks easier to complete. The most common example was accepting patients’ family and friends as informal interpreters – a choice that ran contrary to formal policy of only using professional interpreters. Burnout was reported to be one consequence of excessive workload for patient-centred GPs working with vulnerable groups like asylum seekers. Conclusions. There is a need to improve health literacy amongst African migrants in order to promote preventive behaviours for chronic disease and alternatives to antibiotics for minor illnesses. As part of this, further research is required into the use and properties of traditional African medicine. Interventions should be built upon participants’ existing knowledge of disease causation, their self-reliance in the pursuit of a healthy lifestyle and desire to retain cultural practices. One challenge to improving migrant health lies in the service dilemmas facing GPs, including excessive workload, the complex nature of migrants’ presenting problems and professional dilemmas. GPs who act as advocates for vulnerable migrant patients may be at increased risk of burnout and greater consideration should be given to providing them with appropriate support.