Bibliography: leaves x-xxii / xvii, 285, xxii leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D.)--University of Adelaide, 1987

INTRODUCTION Antioxidant micronutrients may help alleviate oxidative stress in cystic fibrosis (CF) lung disease. To determine treatment effect, systematic reviews (SR) synthesize available evidence. Cochrane SRs are known for being methodologically rigourous, however, may have limited generalizability. OBJECTIVES To assess effectiveness of antioxidant micronutrients in CF lung disease using Cochrane and non-Cochrane SR methodology; to determine whether Cochrane SRs trade relevance for rigour METHODS The first SR followed Cochrane-preferred methods, while the non-Cochrane SR employed a broader search strategy and nclusion criteria. Reviews were contrasted regarding yield of search, treatment effect (efficacy and safety) and risk of bias. RESULTS Neither SR had enough data to support or refute efficacy or safety of antioxidant supplementation in CF lung disease. Compared to the Cochrane SR, the non-Cochrane SR had four more included studies, more precise estimates of efficacy, additional harms data and a similar risk of bias. CONCLUSION Broader search strategies and inclusion criteria may improve relevance of Cochrane SRs without compromising rigour. / Clinical Epidemiology

Thesis (M.S. )--Marshall University, 2009. / Title from document title page. Includes abstract. Document formatted into pages: contains 155 p. Includes bibliographical references p. 151-152.

Chronic microbial infections result from persistent host colonization that is not cleared via the immune response or therapeutics. Within the host, microbes can undergo adaptive evolution, whereby beneficial traits promoting persistence arise due to selection; these traits can therefore affect disease outcomes and treatment strategies. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa is the primary cause of chronic, fatal respiratory infections in individuals with the heritable disease cystic fibrosis (CF). The goal of this dissertation is to identify adaptations that allow P. aeruginosa to persist in the host during chronic CF lung infection. To achieve this goal, P. aeruginosa was chronologically sampled from 3 CF patients, ranging from the first infecting bacterium (the ancestor) to ~40,000 generations post-infection. By comparing gene expression profiles of ancestral and evolved isolates sampled from multiple patients, I identified 24 parallel gene expression changes that occurred over time within each lineage, suggesting that these traits are beneficial to the bacterium. Because most of these traits had unknown physiological roles, I sought to characterize their biological significance. I used a gain-of-function genetic screen and discovered that a subset of these genes enhance biofilm formation, a sessile mode of growth proposed to be important during chronic CF lung infection. I showed that enhanced biofilm formation is due to increased production of the exopolysaccharide Psl, which is traditionally viewed as less critical for maintaining chronic infections than other virulence factors. Lastly, I demonstrated that a majority (~72%) of chronic P. aeruginosa isolates produce more Psl than their corresponding ancestor, suggesting that this exopolysaccharide is important during chronic infection and an adaptive trait. / text

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The purpose of this study was to examine the relationships between inflammation, infection and lung function in cystic fibrosis during the evolution of lung disease in childhood and early adolescence. The developmental stages of childhood and the progression of lung disease together affected the methods and techniques used in the study, with the consequence that the work for this thesis fell naturally into two parts. The first part concerned the study of early lung disease in infants and young children who were unable to expectorate or to cooperate with lung function testing. In the second part, the inflammatory processes in both stable lung disease and during clinical exacerbations in older children and adolescents were studied non-invasively using sputum. The absence of a recognised definition of pulmonary exacerbation lead to further investigation into clinical heterogeneity in the diagnosis and management of an exacerbation. In early lung disease, inflammation was not found to be independent of infection, with pathogens in the lower airways found to correlate with levels of inflammation, respiratory system compliance and degree of air trapping (a relationship not previously shown). This suggested that infection remains the key target to minimizing lung damage in cystic fibrosis. The relationship between sputum markers of inflammation and lung pathology in established disease was found to be less clear, with high inflammation levels in both stability and during exacerbation. Reduction in sputum inflammatory levels following treatment of an exacerbation was found to be greater in those with lower pre-treatment levels. The definition and management of an exacerbation was found to be an area lacking consensus among clinicians, with likely consequent heterogeneity of clinical care and therefore inhomogeneity of hospitalization as a surrogate measure of exacerbation in a research setting. The work from this thesis, and the ensuing publications, has contributed to the understanding of the interactions between the inflammatory and infectious processes involved in CF lungdisease, in both early and more established lung disease in childhood.

The grief experienced by mothers and fathers when their child is diagnosed with a life threatening chronic-illness was investigated in order to validate the presence of grief in these parents and look at the factors that influence it. More specifically, I was interested in whether the grief experience differed for mothers and fathers and the impact that perceptions and coping have on both these gender differences in grief and on grief in general. The particular population investigated in this study were parents of children with Cystic Fibrosis. Participants were recruited through questionnaires randomly sent out by the National Cystic Fibrosis Association. In all, 37 mothers and 15 fathers took part. Results not only confirmed presence of grief in these parents but also indicated that this grief differs for mothers and fathers, with mothers reporting significantly higher levels of physical distress. In line with the literature no gender differences were found in regards to perception of impact parents felt their child's chronic-illness had had on their lives. Contrary to what was expected, however, no differences were found amongst the coping strategies used by mothers and fathers. In regards to the question of which factors have the greatest impact on the grief experienced by mothers and fathers combined, the coping strategy of self-blame was found to be the most important, followed closely by negative perceptions. The significance of these findings and their implications for parents and the people who work with them was discussed.

Doctor of Philosophy / Cystic fibrosis (CF) is the most common inherited lethal disorder among Caucasian populations. Chronic pulmonary infections, particularly from Pseudomonas aeruginosa, are the major determinant of the morbidity and mortality of people with CF. It is generally accepted that people with CF acquire this pathogen independently from their surrounding environment, and that individual CF patients carry unique strains different from others. The spread of this pathogen from patient to patient is thought to be rare and occurs particularly among closely contacted cases such as CF siblings. However, over the past decade, there have been several reports of an emergence of clonal P. aeruginosa strains commonly found infecting a number of CF patients. One such report is from the CF paediatric clinic at the Royal Children’s Hospital in Melbourne in which more than half of the patients were infected with a single strain or clone, subsequently called Australian epidemic strain 1 or AES-1. A preliminary survey showed that AES-1 had spread extensively along the Australian eastern seaboard among CF patients attending other CF centres in Melbourne, Sydney and Brisbane, including adult patients at the Royal Prince Alfred Hospital (RPAH), Sydney. Another clonal strain, subsequently called AES-2, was identified in both CF adults and children at the Prince Charles Hospital and the Royal Children’s Hospital, in Brisbane. The total extent of prevalence of the AES-1 and AES-2 strains at the RPAH as well as the clinical status of patients who carried these strains was unknown. Moreover, the pathogenicity of these two clonal strains had not been investigated. The studies presented in this thesis investigated the prevalence of these clonal strains among CF patients attending the adult CF clinic at RPAH, Sydney by using pulsed-field gel electrophoresis. Overall, 50% of 112 patients with P. aeruginosa were found to be infected with clonal strains. The AES-1 and AES-2 strains were identified in 38% and 5% of the patients respectively. Two new clonal strains, called Sydney-1 and Sydney-2, were also identified. Patients with clonal strains had a significant increase in their number of exacerbations and hospitalisation days, and tended to have lower pulmonary functions when compared to patients infected with non-clonal strains. By using a variety of bioassays to examine the pathogenicity of the clonal and non-clonal strains, it was found that both AES-1 and AES-2 produced more virulence factors and were more resistant to antibiotics when compared to the non-clonal strains. AES-1 and AES-2 were associated with increased production of proteases, including elastase, alkaline protease and protease IV. Overall the results presented in this thesis suggest that there may be a link between virulence and transmissibility of this pathogen. The studies presented in this thesis also compared the biofilm forming capacities of the AES-1 and non-clonal isolates. AES-1 was shown to have greater biofilm-forming capacity than the non-clonal strains, when they were grown on a glass surface, suggesting a possible association between clonality and biofilm formation. A model for the study of bacteria grown in conditions similar to CF sputum was also developed. P. aeruginosa grown in this model was found to develop into clumps which may be comparable to the biofilm structure in the CF lung. This model was shown to be beneficial for transcriptomic and proteomic studies which are underway within the research group. AES-1 was also found to have phenotypic variations between isolates. By applying the amplified fragment length polymorphism technique, more subtypes of this clone were revealed. However, these detected subtypes did not correlate with the different phenotypes, suggesting minor mutations such as single point polymorphisms may be responsible for the phenotypic diversity within the clone. The final part of this thesis was devoted to examining the safety of a novel CF treatment: hypertonic saline (HS) inhalation. HS was shown to increase airway mucociliary clearance, while increased osmolarity associated with the use of HS was also shown to have an inhibitory effect on the formation of biofilms. Findings in this study proved that there was no evidence of strain selection in patients who received the long-term treatment with HS. The study also demonstrated that AES-1 was significantly more persistent in the CF lung than the non-clonal strains. The present thesis not only defines the clonal strains of P. aeruginosa and their implications for infected patients, but also provides a general understanding into the pathogenesis of both clonal and non-clonal strains infecting CF lungs.