Scientific background. Infection remains a major cause of morbidity and technique failure in PD patients. The mechanisms that underpin the clinical severity of peritonitis episodes and their link to outcomes remain poorly defined. γδ T cells together with MAIT cells play a crucial role in orchestrating acute immune responses by the recognition of metabolites (HMB-PP and vitamin B2 derivatives) present in many pathogenic bacteria. My work aimed to understand the molecular and cellular mechanisms underlying the local recognition of bacterial pathogens by peritoneal unconventional T cells, which could be exploited for targeted therapies and novel point of care diagnostic test. Approach. The local and systemic frequency of unconventional T was analysed before and during acute microbial infections, in a well-defined cohort of individuals with end-stage kidney disease receiving peritoneal dialysis (PD). In addition, the responsiveness of peritoneal unconventional T cells to HMB-PP and/or vitamin B2 producing bacteria was assessed ex vivo. Results. This study demonstrated that: (i) peritoneal Vγ9/Vδ2 T cells and MAIT cells are elevated in patients with infections caused by HMB-PP and/or vitamin B2 positive bacteria (e.g. E. coli) but not in infections caused by HMB-PP and vitamin B2 negative species (e.g. Streptococcus ); (ii) peritoneal Vγ9/Vδ2 T cells and MAIT cells are dominant producers of the pro-inflammatory cytokines TNF-α and IFN-γ in response to HMB-PP and/or vitamin B2 positive bacteria; and (iii) in turn, TNF-α and IFN-γ are potent stimulators of peritoneal mesothelial cells and fibroblasts. Outcome analyses showed that infections caused by bacteria that are able to activate Vγ9/Vδ2 T-cells and/or MAIT cells were associated with higher risks of technique failure such as mortality and catheter removal. Conclusions. My studies provide a molecular basis for the existence of pathogen-specific immune fingerprints that have diagnostic and prognostic value, identify key pathways by which unconventional T-cells can amplify early inflammatory responses, and highlight potential therapeutic targets that may be exploited to improve outcomes.

Atherosclerosis is a chronic inflammatory disorder characterised by lipid accumulation in the arterial wall. Nutraceuticals represent promising alternatives to pharmaceuticals in the prevention and management of this disease. Previous work has shown an omega-6 fatty acid, dihomo-gamma-linolenic acid (DGLA) to inhibit atherosclerosis in a mouse model of the disease. Understanding the molecular mechanism underlying the action of DGLA in atherosclerosis is crucial to evaluating the role of this PUFA as a new agent in the prevention/treatment of the disease. In vitro analysis utilised macrophage cell lines THP-1 and RAW264.7 together with primary cultures of human monocyte-derived macrophages to study the effects of DGLA on aspects of macrophage foam cell formation, an early event in atherosclerosis. Data presented in the thesis showed that DGLA had an effect on a number of key events that contribute to foam cell formation in macrophages; reducing monocyte migration, pro-inflammatory cytokine induced gene expression, modified LDL uptake, scavenger receptor expression, macropinocytosis and cholesteryl ester accumulation and stimulating cholesterol efflux. Uptake of DGLA into lipid fractions was studied in vitro and in vivo using thin layer chromatography and gas chromatography. DGLA was significantly incorporated in a dose-dependent manner into lipid fractions of THP-1 macrophages in vitro. In vivo, mice fed a 4.4% DGLA containing diet assimilated the PUFA into serum, liver, kidney and adipose tissue lipid fractions. Finally, the metabolism of DGLA was investigated in vitro. DGLA supplementation stimulated the production of PGE1 and 15-HETrE in macrophages. PGE1 inhibited monocyte migration and IFN-γ induced expression of monocyte chemotactic protein 1 (MCP-1). RNA interference assays showed a key role for COX enzymes in the IFN-γ-mediated induction of MCP-1 expression. Findings in the thesis demonstrate key mechanisms underlying the anti-atherogenic role of DGLA and highlight its potential as a therapeutic/preventative agent in this disease.

The move to electronic discharge summary systems was anticipated to solve the longstanding problems associated with poor data quality and reduce delay in the production and transmission of discharge summaries between secondary and primary care health care providers in the UK National Health Service. A consequence of investment in a national IT infrastructure for electronic health records has focused attention on template design and the IT system requirements. The routine practices of doctors involved in discharge summary construction, and other factors that contribute to the problems of delay and data quality, have been less well explored. This study aimed to gain an understanding of paper-based discharge summary construction in a secondary care context in order to identify and analyse the implications for improving electronic discharge summary systems, and potentially avoid inadvertent transfer of inherent problems. A mixed method case study design was used to examine the patient discharge process and the construction of discharge summaries in one NHS Hospital Trust. Data was collected through semi-structured interviews with hospital doctors (n=10) and simulated discharge summary production (n=10). A syntactic analysis was also performed on discharge summaries (n=11) and proformas (n=3). The data was analysed thematically and inductively in order to identify the factors that contribute to the twin problems of data quality and delay associated with discharge summaries. The pragmatic, semantic, syntactic conceptual framework (Morris, 1938), and Speech Act (Austin, 1962) and Mental Frame (Minsky,1981) theories, were used to analyse how information contained in discharge summaries was represented, interpreted and used. This study found that moving from a paper based to an electronic discharge summary system will not necessarily resolve the problems of poor data quality and delayed production of discharge summaries. More comprehensive solutions are required in order to facilitate more effective discharge summary communication between secondary and primary care health professionals, and to address entrenched custom and practice in current hospital practice. These include uni-professional (medical) orientation of discharge summaries, attitude of senior doctors, inadequate preparation of junior doctors, inconsistent data entry including absence of common usage of short forms and abbreviations, and little accountability for quality control. Recommendations include training for junior doctors, regulating the use of shortened forms, improving the features of data entry systems, structuring the clinical coding data and introducing systems to ensure greater organizational accountability for effective discharge communication. More comprehensive change related to the introduction of multidisciplinary contribution discharge summary construction and integration of discharge summary standards in care pathways may improve overall discharge summary quality.

No description available.

It has been proposed that long-term consumption of diets rich in non-digestible carbohydrates (NDCs), such as cereals, fruit and vegetables might protect against several chronic diseases, however, it has been difficult to fully establish their impact on health in epidemiology studies. The wide range properties of the different NDCs may dilution their impact when they are combined in one category for statistical comparisons in correlations or multivariate analysis. Several mechanisms have been suggested to explain the protective effects of NDCs, including increased stool bulk, dilution of carcinogens in the colonic lumen, reduced transit time, lowering pH, and bacterial fermentation to short chain fatty acids (SCFA) in the colon. However, it is very difficult to measure SCFA in humans in vivo with any accuracy, so epidemiological studies on the impact of SCFA are not feasible. Most studies use dietary fibre (DF) or Non-Starch Polysaccharides (NSP) intake to estimate the levels, but not all fibres or NSP are equally fermentable. It has been proposed that long-term consumption of diets rich in non-digestible carbohydrates (NDCs), such as cereals, fruit and vegetables might protect against several chronic diseases, however, it has been difficult to fully establish their impact on health in epidemiology studies. The wide range properties of the different NDCs may dilution their impact when they are combined in one category for statistical comparisons in correlations or multivariate analysis. Several mechanisms have been suggested to explain the protective effects of NDCs, including increased stool bulk, dilution of carcinogens in the colonic lumen, reduced transit time, lowering pH, and bacterial fermentation to short chain fatty acids (SCFA) in the colon. However, it is very difficult to measure SCFA in humans in vivo with any accuracy, so epidemiological studies on the impact of SCFA are not feasible. Most studies use dietary fibre (DF) or Non-Starch Polysaccharides (NSP) intake to estimate the levels, but not all fibres or NSP are equally fermentable. The first aim of this thesis was the development of the equations used to estimate the amount of FC that reaches the human colon and is fermented fully to SCFA by the colonic bacteria. Therefore, several studies were examined for evidence to determine the different percentages of each type of NDCs that should be included in the final model, based on how much NDCs entered the colon intact and also to what extent they were fermented to SCFA in vivo. Our model equations are FC-DF or NSP$ 1: 100 % Soluble + 10 % insoluble + 100 % NDOs¥ + 5 % TS** FC-DF or NSP 2: 100 % Soluble + 50 % insoluble + 100 % NDOs + 5 % TS FC-DF* or NSP 3: 100 % Soluble + 10 % insoluble + 100 % NDOs + 10 % TS FC-DF or NSP 4: 100 % Soluble + 50 % insoluble + 100 % NDOs + 10 % TS *DF: Dietary fibre; **TS: Total starch; $NSP: non-starch polysaccharide; ¥NDOs: non-digestible oligosaccharide The second study of this thesis aimed to examine all four predicted FC-DF and FC-NSP equations developed, to estimate FC from dietary records against urinary colonic NDCs fermentation biomarkers. The main finding of a cross-sectional comparison of habitual diet with urinary excretion of SCFA products, showed weak but significant correlation between the 24 h urinary excretion of SCFA and acetate with the estimated FC-DF 4 and FC-NSP 4 when considering all of the study participants (n = 122). Similar correlations were observed with the data for valid participants (n = 78). It was also observed that FC-DF and FC-NSP had positive correlations with 24 h urinary acetate and SCFA compared with DF and NSP alone. Hence, it could be hypothesised that using the developed index to estimate FC in the diet form dietary records, might predict SCFA production in the colon in vivo in humans. The next study in this thesis aimed to validate the FC equations developed using in vitro models of small intestinal digestion and human colon fermentation. The main findings in these in vitro studies were that there were several strong agreements between the amounts of SCFA produced after actual in vitro fermentation of single fibre and different mixtures of NDCs, and those predicted by the estimated FC from our developed equation FC-DF 4. These results which demonstrated a strong relationship between SCFA production in vitro from a range of fermentations of single fibres and mixtures of NDCs and that from the predicted FC equation, support the use of the FC equation for estimation of FC from dietary records. Therefore, we can conclude that the newly developed predicted equations have been deemed a valid and practical tool to assess SCFA productions for in vitro fermentation.

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No description available.

Chronic respiratory diseases (CRD) commonly present with abnormal breathing patterns at rest. There is some limited evidence that breathing patterns during speech (speech breathing patterns), differ in CRD compared to healthy individuals. Monitoring speech breathing patterns could provide useful information about changes in respiratory health, however, little is currently known about speech breathing patterns in CRD. This research aimed to explore and evaluate speech protocols, and characterise speech breathing patterns in health and CRD. Information gathered was taken forward to explore the impact (if any) on speech breathing patterns in patients with CRD before and after Pulmonary Rehabilitation (PR). Respiratory Inductive Plethysmography (RIP) was used to quantify breathing/speech breathing patterns during various speech tasks in three studies. In the first study, 29 healthy adults and 11 adults with self-reported asthma were characterised and speech breathing protocols were evaluated. The second study characterised 20 healthy older adults, and 20 patients with CRD (COPD=14, bronchiectasis=6) were assessed before and after a six week PR programme in the third study. Key novel findings were: 1) Breathing patterns were task specific between speech in healthy younger adults, but this finding could not be generalised to healthy older adults or patients with CRD. 2) Speech breathing patterns differed between health and CRD, but were not disease specific. 3) A recording period of two minutes was sufficient to provide stable breathing parameters 4) Conversational speech was most useful for assessing speech breathing patterns. 5) No changes in speech breathing patterns were observed after PR, but no changes in resting breathlessness or oxygen saturation were observed either. Conclusion: This research has permitted the optimisation of speech protocols for future research and produced new evidence from patient groups that contradicts previous assumptions about task specificity. This research has not produced any evidence to support the hypothesis that speech breathing patterns are responsive to an intervention.

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No description available.