The traditional modular account of memory segregates visual associative memory and visual perception, with the former underpinned by the medial temporal lobes (MTL) and the latter by posterior visual regions. By contrast, the representational account of memory envisages visual associative memory as a perceptual-mnemonic continuum that can be traced from early visual cortex to anterior MTL structures. In this thesis, we tested these fundamentally different memory models by using a novel between-group design with young grapheme-colour synaesthetes, older adults and young controls, each of whom have their respective strengths and weaknesses in memory and perception. Specifically, grapheme-colour synaesthetes possess enhanced perceptual mechanisms, allowing them to experience black letters, words or digits as inherently coloured. They also show enhanced early visual cortex sensitivity in response to non-synaesthesia inducing stimuli (Barnett et al., 2008) as well as enhanced memory for verbal and visual stimuli. Using psychophysical techniques and functional magnetic resonance imaging (fMRI), we compared these three groups on a range of cognitive processes involved in visual associative memory: encoding, working memory, associative retrieval and recognition.

Background: This PhD is part of the Wellcome Trust funded London and Brighton Translational Ethics Centre (LABTEC) Project investigating the social impact of developments in stem cell research and neuroscience. It contributes to the overall project by giving voice to the patient experience when faced with Parkinson’s, a serious progressive, degenerative and incurable neurological disease. Aim: The aim of this study is to provide a rich narrative account of how individuals diagnosed with Parkinson’s negotiate their illness, paying particular attention to the personal, social and historical conditions that mediate people’s stories. Methods: The study uses the data emerging from 37 interviews conducted with individuals whose experience of a Parkinson’s diagnosis ranged from 3 months to 33 years, and whose age at diagnosis ranged from 29 to 78 years. Methodologically, it is informed by Arthur Frank’s concept of dialogical narrative analysis (DNA), at the heart of which lies the desire to hear the different voices in any one person’s story. DNA is interested in hearing how stories shape participants’ understanding and experience of illness. At the same time, it recognises that stories have no ending because people constantly retell them in order to develop and revise their understanding of self. Findings: This study illustrates the importance of stories in enabling participants to reclaim their experience of Parkinson’s from others’ narrative representations of them. It also gives voice to the human significance of diagnosis after finding that, for many participants, the diagnostic encounter not only lacked ceremony but was also a point at which their voices were all but silenced. Finally, using Frank’s illness typology of restitution, chaos and quest as a ‘listening device,’ it becomes possible to hear the existential challenges facing participants as they try and make sense of their illness in the context of a society where restitution remains the preferred narrative and the search for a cure remains a stated goal of scientific research into Parkinson’s disease. Conclusion: The final thesis is a methodologically novel contribution to empirical bioethics which will inform discussions around policy and practice relating to the care and treatment of people with this particular neurodegenerative disease.

Intravesical Bacillus Calmette–Guérin (BCG) immunotherapy is the main treatment for bladder high-grade non-muscle invasive transitional cell carcinoma (HGNMITCC) following initial resection. Unfortunately, about 30% of patients will not respond to treatment and they carry a high risk of disease progression. The alternative, radical cystectomy, has major risks with high morbidity and mortality. The ability to predict the response to BCG treatment would be a useful tool in the selection of appropriate treatment modalities. This study investigated a variety of detectable immune responses in blood and urine to establish if there were differences between responders and non-responders to BCG treatment. We evaluated whether there were detectable immunological differences in blood or urine that could explain or predict outcome.

Strategic drives and policy initiatives position mobile technology – or mHealth - as a means of addressing current healthcare challenges. However, mobile phones differ from other health technologies due to their ‘ground-up’ adoption, personal ownership and multiplicity of purpose. Prevailing paradigms in mHealth research cannot account for the range of ways mobile phone use is enacted in the hospital setting and therefore cannot support the level of enquiry required to explore new possibilities for care and learning. By adopting a ‘practice’ approach that draws focus to how mobile phone use is enacted in situ, this research reconceptualises care and phone use as sociomaterial practice, enabling the mutual shaping of mobile phones and social practices to be described. To achieve this end, the ward round was selected as a ‘case’ through which the mobile phone use of patients, clinical staff and students could be observed. Ethnographic methods of observation were combined with interviews to collect data from two different wards within the same hospital trust over a six month period in 2013. The primary research question addressed was “How are mobile phones being integrated into healthcare practices in the hospital setting?” Findings from this research show that phones are enacted as transient members of the ward round; visible at moments, then hidden from view. They contribute to the distributed and shared nature of care, loosening the constraints of time and space that are so critical to the ward round whilst simultaneously reproducing them. As such they play an important role in boundary work and in enabling and constraining boundary ‘spillover’. Participants using mobile phones on the ward found ways to benefit from the potentialities of mobile phone use but also had to engage with the complexities of spillover, how to ‘be’ on the ward and how to use phones appropriately. This research shows that the spaces and rhythms within which care is enacted on the ward produce ‘boundary work’ which mobile phone users learn to negotiate. Each episode of use is distinct, contingent and requires nuanced judgements that balance possibilities with safety and ethics. The thesis concludes by arguing top-down hospital safety and quality efforts are likely to struggle to address all the variables of situated practice relevant to mHealth. Nonetheless, working with, rather than against mobile phones in care practice requires an appreciation of empirical ethics and open discussion to allow new practices to emerge whilst safeguarding the interests of all involved.

Whole genome sequencing has recently identified DIS3 as a novel tumour suppressor gene in multiple myeloma. DIS3 is a conserved RNA exonuclease and catalytic subunit of the exosome, a protein complex involved in the 3’ to 5’ degradation and processing of messenger RNA and small RNAs. Messenger RNA processing and degradation is important in controlling gene expression and therefore cellular function, however the role DIS3 plays in the pathogenesis of haematological cancer remains unclear. Using RNAi as a means to knock-down DIS3, I have performed various functional assays to investigate the consequences of DIS3 loss-of function on myeloma cells. I have investigated cell viability, drug-sensitivity, mitotic errors, apoptosis and the generation of double-strand breaks in both transiently transfected myeloma cells and stable transfected adherent cells. I have also performed transcript profiling experiments in the form of RNA-sequencing to identify possible targets of DIS3 as well as synthetic lethality screens to identify proteins that may be cooperating with DIS3 mutations in myeloma pathogenesis. Overall, DIS3 knock-down did not appear to affect cellular phenotype in these assays, possibly indicating that DIS3 may be conferring a competitive advantage to cancer cells through a mechanism that only occurs in vivo. Alternatively, DIS3 mutations may not be driving tumourigenesis on their own but may either require another cellular pathway to be disrupted, or, may only be required to maintain the tumour rather than initiate it. In addition to investigating the role of DIS3 in oncogenesis, I have also studied the normal physiological role of DIS3 within the cell. I have confirmed the presence of two alternatively spliced, protein-coding transcripts of DIS3 that differ in the size of their endoribonucleolytic PIN domain. My work has characterised the levels of these two isoforms in cell lines and in tissues from humans with various haematological cancers. Isoform 1 appeared to be the principal transcript in cell lines as well as myeloma and AML patient cells. However, in CMML and healthy controls, the ratios of each isoform are more equal and often isoform 2 is more highly expressed than isoform 1. Activity assays indicated a difference in the ability of the shorter isoform to degrade circular RNAs, suggesting isoform 2 may have reduced endonucleolytic function. Initial work has also identified a link between the higher expression of isoform 2 in CMML patients and common mutations in the splicing gene SRSF2. This suggests the expression of the endonucleolyticallyreduced DIS3 isoform 2, may contribute towards a CMML phenotype. Although this project was unable to identify the role of DIS3 in myeloma development, there is strong evidence that mutations in this gene are being positively selected and confer an advantage to cancer cells. More sophisticated experiments may need to be conducted whereby the in vivo environment is mimicked more effectively, through the generation of a mutant mouse model. Only once we understand the picture more fully, can we begin to design targeted molecular therapies for affected patients.

Alzheimer’s disease (AD) is associated with a prodromal stage of cognitive decline, manifest clinically as mild cognitive impairment (MCI) that progresses ultimately to a stage of dementia. There is an urgent need to recognise AD at its earliest clinical stages, which entails distinguishing AD from other conditions, particularly other neurodegenerative diseases, but at a time when clinical symptoms are non-specific. Investigations such as neuropsychological testing and neuroimaging, using MRI and PET to determine changes in brain structure and metabolism respectively, provide additional useful diagnostic information, the changes associated with these tests now incorporated into diagnostic criteria. These studies aimed to investigate AD and Frontotemporal dementia (FTD) using these investigative tools, with a particular focus on AD in keeping with its central importance as the commonest cause of dementia. Early AD was the focus of the first study. Given the involvement of the hippocampus from the initial stages of AD, and of the role of the hippocampus in spatial memory, the study hypothesis was that a hippocampus-sensitive test of spatial memory would discriminate prodromal AD and mild AD dementia with high sensitivity and specificity. The 4 Mountains Test of spatial memory (4MT) was chosen in view of its potential usability across different cultural settings. The second study focused on dementia due to AD and FTD. Given the diagnostic importance of MRI and PET changes, this study aimed to measure the concordance of atrophy and hypometabolism in six syndromic variants of AD and FTD. The primary hypothesis was that concordance would differ across different AD and FTD syndromes, with a secondary hypothesis that determination of the topographical extent of atrophy and hypometabolism would differ according to the method used to determine imaging changes.

The Toll-like receptors (TLRs) are a family of highly conserved pattern recognition receptors involved in the detection of pathogenic invasion and tissue damage. Activation of TLRs can occur through binding to pathogen associated molecular patterns (PAMPs) but also host derived damage associated molecular patterns (DAMPs), which are highly abundant in the OA joint (Sokolove and Lepus, 2013). Originally thought of as a disease of wear and tear, osteoarthritis (OA) is better described as a disease of chronic inflammation, with the production of pro-inflammatory and degenerative products perpetuating disease activity. Resident joint cells can react through TLRs to these damage products and thereby induce the production and secretion of pro-inflammatory cytokines and matrix degradative enzymes. This study sought to identify TLR expression and activity within synovial fibroblasts categorised by joint location and cartilage sub-categorised by OA progression. TLR induced pro-inflammatory cytokine induction from these cells along with matrix degenerative enzyme production was analysed to determine the pathogenic contribution of the cell types. Significant differences in expression of TLR2, TLR3 and TLR4 were noted between hip and knee derived synovial fibroblasts. Increased expression correlated to a higher pro-inflammatory cytokine production from knee opposed to hip derived synovial fibroblasts. This difference in inflammatory cytokines production comparing knee to hip became even more apparent when observing spontaneous production from synovial membrane cultures that demonstrated TNF, IL-6 and IL-8 to be significantly higher in cultures from the knee opposed to hip. Knee synovial fluid was also noted to have a significantly lower level of MMP1 compared with hip derived samples supporting a hypothesis that knee and hip osteoarthritis pathogeneses may differ. Analysis of articular chondrocytes at different stages of disease progression demonstrated altered phenotypes. Chondrocytes isolated from regions of degeneration had an altered TLR expression pattern and subsequently produced significantly elevated IL-6 and MMP13 following TLR stimulation relative to those isolated from intact regions of cartilage. These data suggest that TLR-induced cytokine secretion by synovial fibroblasts and chondrocytes potentially contribute to disease pathology and hypothetically have two separate phenotypes of disease progression. It also highlights the possible need for tailored treatment of OA dependent on joint location providing some explanation of differences in efficacy of trialled biologic therapies.

The gene pacman (pcm) in Drosophila melanogaster encodes the exoribonuclease XRN1, which is highly conserved across eukaryotes and is the only known cytoplasmic exoribonuclease that degrades RNA in the 5’ – 3’ direction. Hypomorphic mutations to pacman have previously been shown cause developmental phenotypes, particularly during wing and thorax development. The focus of this thesis was twofold. Firstly, to create a null pacman allele and associated control lines to further characterise the phenotypes of pcm. Two new alleles were created, one of which was amorphic (pcm14). pcm14 is 100% lethal, and flies die during pupation. The wing imaginal discs of pcm14 larvae are less than half the size of those in wild‐type larvae at the same stage (3rd instar). It was also found that wing imaginal discs in the hypomorphic mutant pcm5 are significantly smaller than wild‐type, by almost 20%. Therefore, pcm appears to play a role in cell proliferation or apoptosis during the growth of wing imaginal discs. Along with pcm14, a new deficiency that includes pcm was created using a DrosDel Rearrangement Screen. The 17,963bp Df(1)ED7452 deficiency is >13 times smaller than the two other publically available deficiencies that include pcm.

Clostridium difficile infection (CDI) is the leading cause of nosocomial diarrhoea and causes substantial morbidity and mortality. Efforts to reduce the impact of CDI have succeeded in reducing rates through antibiotic stewardship, improved diagnostic testing and optimisation of infection control measures. Further reductions in CDI could be achieved through a better understanding of what makes patients susceptible to CDI. Such knowledge would support interventions targeting patients most at risk and help develop treatments to reduce susceptibility. The aim of this thesis was to further our understanding of patient susceptibility to CDI by investigation of three specific areas. The first study investigated the role of the probiotic Lactobacillus casei DN114001 in preventing antibiotic associated diarrhoea (AAD), including CDI, as part of a large multicentre, double-blind, randomised placebo-controlled trial. Probiotics are live microorganisms that may help restore antibiotic disruption to the host microflora and prevent C. difficile colonisation. The final results were not available at the time of writing this thesis and therefore a descriptive analysis of the first 650 blinded cases is provided. This is the largest probiotic study ever conducted and will contribute significantly to the existing literature in the field. The humoral immune response has been implicated in determining outcome in CDI. Previous studies have focused on recurrence of CDI and toxin A (TcdA), which was originally thought to be the most important virulence factor in CDI. However, recent studies have suggested toxin B (TcdB) may be essential for CDI pathogenesis. Therefore, the second study tested the hypothesis that antibodies to TcdB determine patient susceptibility in CDI. A case-control laboratory based study was conducted using a novel antibody ELISA and antibody responses to both toxins were assessed in two cohorts recruited in Brighton, UK and Michigan, USA. Lower antibody levels to TcdB, but not TcdA, were found in cases of acute CDI compared to controls. These novel findings are in contrast to previous studies and confirm the importance of TcdB in CDI pathogenesis. In addition, the antibody response to TcdB could be used as a surrogate marker for the efficacy of novel therapeutic agents. The third study sought to identify risk factors predicting recurrence of CDI. A longitudinal cohort study of 248 patients with confirmed CDI was conducted that confirmed the previously observed relationship between concomitant antibiotic treatment and risk of recurrence. The study also identified a novel risk factor namely that treatment on a cohort ward was associated with recurrence of CDI. This is likely to be a result of reinfection of patients who remain susceptible to CDI after treatment. This is the first study to demonstrate an association between cohorting of patients and recurrence of CDI and raises important questions about current infection control policies in hospitals. Efforts to combat CDI have focused on reducing exposure of patients to infection. The data presented here contribute to a rapidly emerging understanding that patient susceptibility is a crucial factor in determining risk of infection, risk of severe disease and risk of recurrence following treatment. In the near future interventions targeting susceptibility including probiotics, specific antibiotics such as fidaxomicin and immunotherapies such as vaccines may all have a role to play in combatting this devastating disease.

Background and Aims: Hepatic steatosis (≥10% fat within the liver) affects ~75% of obese and ~15% of non-obese adults. It leads to steatohepatitis (SH) in ~10% of patients. SH may then lead to cirrhosis. The primary aim of the thesis was to image the liver with FDG PET/CT to determine if glucose utilisation rate (MRglu) is increased in steatosis. Texture analysis of FDG PET/CT was also explored as a means of detecting steatosis and SH. Previous PET studies of steatosis quantified hepatic FDG uptake as the standardised uptake value (SUV). Methods: All patients were referred for routine PET/CT. ROI were placed over the liver on whole body scans for measurement of CT density, which is inversely proportional to hepatic fat content, and SUV. SUV may be expressed as the ‘hottest’ pixel (SUVmax) or as the average of all pixels in the ROI (SUVave). Dynamic imaging from 0-30 min post-injection was also done in 60 patients and hepatic FDG clearance and MRglu were measured using Patlak-Rutland analysis. Texture analysis of PET and CT scans was explored as possible means of identifying SH at an early stage. Results: SUV was overestimated in obese individuals when calculated using weight but not when using estimated lean body mass. SUVmax, but not SUVave, was increased in steatosis because SUVave is reduced in fatty liver as a result of ‘signal dilution’ by the fat. SUVmax/SUVave is therefore a marker of steatosis. Hepatic FDG clearance and MRglu were increased in steatosis, irrespective of BMI, but not in obese patients who did not have steatosis. Results of texture analysis were promising but inconclusive. Conclusions and future work: SUV has major shortcomings as a surrogate for FDG clearance but in general indicates increased MRglu in steatosis. Dynamic studies confirm that MRglu is increased in steatosis. SUVmax/SUVave is a marker of steatosis. Future work should aim to a) use dynamic FDG imaging to diagnose hepatic inflammation, and b) explore texture analysis to detect transition from steatosis to SH.