There is a high prevalence of exercise induced bronchoconstriction (EIB) in elite athletes. It has been suggested that damage to the airway epithelium is the key effector process and that EIB in athletes is due to different mechanisms than exercise induced asthma. Whether testing strategies are as valid in athletes is controversial, but regulatory bodies continue to advocate the use of objective tests for diagnosis. How responses to these relate to sport, airways inflammation and to symptoms is unclear. We investigated responses to direct and indirect challenge tests and patterns of airways inflammation in symptomatic, international, endurance athletes. We focused on differences between pool-based and non-pool based endurance athletes to see if environmental factors played a significant role. We also investigated the interaction between airways epithelial and human lung mast cells in vitro and compared these between healthy and asthmatic donors. Of the challenges assessed, EVH related most closely to eosinophilic airways inflammation. The other tests examined did not relate particularly closely to each other, to eosinophilic airways inflammation or to markers of mast cell activation. There were no differences between pool and non-pool based athletes in terms of patterns of airways inflammation or airway mediator release in response to challenge testing. Pool-based athletes had significantly more airways hypereactivity when compared to non-pool based athletes. Those who test positive to EVH have more eosinophilic airways inflammation and more epithelial cells in their sputum than those who have a negative test. All indirect challenge tests increased the level of PGE2 in the airways compared to direct testing, even when corrected for degree of bronchoconstriction, suggesting epithelial stress. In vitro, an intact, healthy epithelium significantly suppresses constituitive and IgE mediated human lung mast cell histamine secretion. This suppression is attenuated in asthmatic or injured epithelium and is mediated by a small, labile, lipid soluble mediator. There is a significant heterogeneity in airways inflammation and airways hyperreactivity in elite performance athletes. The role of the epithelial cell in the development of EIB requires further exploration. The interaction between the epithelium and human lung mast cells needs to be fully elucidated and its potential for therapeutic manipulation further explored.

Chemokine receptors CCR4 and CRTH2, both expressed preferentially on Th2 cells, have been proposed to play an important role in the recruitment of T cells in asthma. The aim of this thesis was to see if fu.rther evidence of the role of CCR4 and its ligands CCLl7 and CCL22 in allergic asthma could be obtained in a combination of descriptive and functional studies. Differences in the expression ofCCR4 and CRTH2 on peripheral blood T cells from healthy non-atopic subjects and mild atopic asthmatic patients were looked for. Also the expression of a selection of activation/memory markers on CD4+ T cells were studied to determine whether there are any differences in the co-expression ofthese markers on CCR4+ T cells between the two subject groups. In order to try and confirm or deny findings in peripheral blood, immunohistochemistry was used to look for any differences in the expression of CCR4 in bronchial biopsy tissue sections of healthy control and asthmatic subjects. A bronchial explant model was used to look for differences in the production of a selection of. cytokines and chemokines (the main focus being on CCLl7 and CCL22) between healthy and house dust mite allergic asthmatics. Bronchial biopsies from healthy and asthmatic subjects were cultured for 24 hr with/without allergen and supernatants were assessed for cytokines and chemokines. The chemotactic responses of a CCR4+ T cell line and peripheral blood T cells, polarised in vitro torwards a Th2 phenotype were assessed; to recombinant chemokines and bronchial biopsy supernatants from asthmatic and healthy subjects stimulated ex vivo with allergen. A final aim, using peripheral blood mononuclear cells from allergic asthmatics was to elucidate whether CCR4+ cells contain allergen specific T cells by assessing lL-5 production following stimulation with allergen of whole PBMC and PBMC depleted of CCR4+ cells. There were no significant differences between healthy subjects and asthmatic patients in levels of expression of CCR4 and CRTH2 on CD4+ T cells and expression of . activation/memory markers on either CD4+ or CCR4+ICD4+ T cells. Sections of bronchial biopsies from healthy or asthmatic subjects were found not to contain any CCR4 positive cells. Analysis of bronchial explant supernatants showed significantly decreased lL-2 production in allergen-challenged when compared to unchallenged explants in healthy controls. Allergen induced a significant increase in IL-5 (p=<0.001) in asthmatic explants; this was significantly higher when compared to lL-5 measured in stimulated explants from healthy controls (p=<O.OOI). Allergen stimulation of explants from asthmatics but not control subjects also resulted in increased lL-4 release (p=0.015). Comparison of challenged explants from asthmatics and healthy control subjects also showed an increase in IL-13 production in asthmatic patients (p=0.014). CCLl7 production increased significantly in the asthmatic explants only with sigriificant differences between healthy subjects and asthmatics for both unchallenged and challenged samples (p=0.008 and 0.001 respectively). Further significant differences (Le. increased production in asthmatic explants were seen for CCL22 (p=0.004), CCL2 (p=O.013), CCLl9 (p=O.04), CCL20 (p=0.013) and CCLlI (p=O.002). Stimulation of PBMC from asthmatic donors wit~ allergen resulted in increased IL-5 which was significantly reduced by selective depletion of CCR4+ cells (p=O.021), strongly suggesting that CCR4+ cells were the source of Th2 cytokines. In a final series of experiments where explant supernatants were used as the chemotactic stimulus, chemotactic activity that was dependent on CCR4 was not shown. The supernatants from healthy and asthmatic subjects failed. to induce chemotactic activity of either the CCRF-CEM ceHs line with constitutive CCR4 expression or Th2 T cells polarised' ex vivo. . In conclusion despite being able to demonstrate that the CCR4+ cell population contains T cells which produce Th2 cytokines and that bronchial tissue from asthmatic individuals stimulated ex vivo produces the CCR4 ligands, CCLl7 and CCL22, chemotactic activity for T cells to explant supernatants was not observed.

Part I.  Aims: The aims of part I of this research programme were to: measure the prevalence of antibiotic prescription for U.R.T.I. in Primary Health Care Centres in the United Arab Emirates; understand the rational behind antibiotic prescription; Evaluate the effect of different patient characteristics such as self treatment, age, education, occupation and gender; evaluate the effect of physician characteristics such as gender, communication and practice location;  and to evaluate the degree of patient compliance and satisfaction with treatment. Main Conclusions: U.R.T.I. is one of the main reasons for patient visits and antibiotic prescription; physicians’ advice to patients regarding dosage and duration of the prescribed medication was limited; a significant association existed between patients’ expectation from practitioners and practitioners’ perception of patients’ expectations; poor compliance is strongly correlated with poor patient-doctor interaction; diagnoses were typically based on clinical findings; patient satisfaction is strongly linked to the level of communication. Part II.  Aims: To measure the influence of introducing guidelines to doctors and educational leaflets to patients on reducing the level of prescribed antibiotics; and to investigate the effect of factors such as socio-demographic characteristics, signs, symptoms and patient self management. Main Results: The total number of antibiotic prescriptions for patients suffering from U.R.T.I. including sore throat was significantly reduced in the intervention group. Conclusions: A multi-dimensional interventional approach for reducing antibiotic prescription in U.A.E. clinics resulted in a significant positive outcome; and the significant reduction in antibiotic prescriptions indicates the willingness of physicians to follow guidelines and the willingness of patients to respond to educational information. Main Recommendations:  Clinical guidelines are most effective if implemented as part of a systemic strategy, involving dissemination of guidelines by departmental heads and utilisation of computer generated reminders; physicians should be involved as part of the working group to develop guidelines; ongoing educational programmes for physicians; and a public educational campaign on the problem of over use of antibiotics is essential.

Between 1991-1999, the Patient Episode Database for Wales (PEDW) was investigated and an association between influenza A viruses circulating in the community and demand for inpatient management of lower respiratory tract illness demonstrated r=0.73 a finding which supports influenza contributing significantly to the winter bed crises seen in the Welsh NHS in recent years. Once admitted to hospital, the clinical outcomes of influenza and pneumonia are poor the average length of the inpatient stay being 14 days with approximately one third of elderly and high-risk individuals dying during the inpatient period. To assess the effectiveness of the inactivated influenza vaccine in preventing such hospitalisations, a prospective case-control study was undertaken in Gwent, South East Wales during the winter of 1999-2000. After controlling for age, sex, chronic disease status, pneumococcal vaccine uptake, previous inpatient management and primary care consultations in an unconditional logistic model, the inactivated influenza vaccine was found to reduce admissions for acute respiratory illness significantly OR .30 (95% CI: .21 to .44 ) this translating to a 70% reduction in admissions. Furthermore, the risk of death once hospitalised was reduced by 75% in vaccinees OR .25 (95% CI:.l 1 to .60). Vaccination coverage in South East Wales during this season was poor and examination of the determinants of respiratory vaccine uptake suggests that the chronic medical conditions for which vaccination are recommended are not equally weighted. Vaccines appear to be targeted at individuals with chronic pulmonary disease, leaving many other high-risk groups, particularly individuals with cardiovascular disease vulnerable to influenza and its sequelae. Smokers were also significantly less likely to have received the influenza and pneumococcal vaccines, the OR's being .40 (95% CI: .27 to .57) and .57 (95% CI: .36 to .91) respectively. The widespread use of respiratory vaccines in elderly and identified high-risk groups has substantial resource implications for secondary care services in Wales. The review of the literature in Chapters 1 and 2 highlights a paucity of epidemiological data on the impact of influenza and pneumonia within a UK setting. Furthermore, the evidence base for influenza and pneumococcal vaccination, both of which are integral components of primary care prevention strategies, rests on observational studies conducted predominantly in North America. This thesis aims to draw together a number of studies to develop an epidemiological picture of individuals hospitalised with influenza and pneumonia during the 1990s in Wales. Furthermore, specific public health issues, such as the delivery and uptake of respiratory vaccines and the effectiveness of influenza vaccination are examined. The methodologies of the studies are outlined in chapter 3. In Chapter 4, trends of hospitalisations for influenza and pneumonia in Wales are examined and mean annual rates of hospitalisations for influenza, pneumococcal pneumonia and broad sub categories of pneumonia reported. The relationship between surveillance data reporting influenza like illness at primary care level and demand for inpatient management of lower respiratory tract illness is examined. The hypothesis that influenza contributes significantly to the winter bed crisis in the Welsh NHS is also investigated. Potential risk factors for and outcomes of hospitalisation due to influenza and pneumonia are also reported which subsequently inform the planning of the case control study outlined in Chapters 3 and 5. In addition, the missed opportunity for reducing the demand for inpatient management of vaccine preventable respiratory disease is assessed and determinants of influenza and pneumococcal vaccine uptake described. Finally, in Chapter 5, the effectiveness of the inactivated influenza vaccine in reducing admissions for respiratory disease during an influenza outbreak period is reported and the impact of increased acute respiratory admissions on a district general hospital in South East Wales described.

The aim of this thesis was to obtain a mouse model of asthma to increase understanding of asthma pathogenesis and to investigate the mechanisms leading to gender differences. For this purpose, in vivo models of allergic asthma were developed and characterised in male and female mice to address both the acute and chronic conditions of the asthmatic airways. Male and female BALB/c mice were sensitised and challenged with the allergen, ovalbumin OVA, following acute and chronic protocols. The novel murine asthmatic models were characterised by the investigation of airway inflammation, airway hyperresponsiveness AHR, antibody production, eosinophil degranulation, plasma protein extravasation and production of nitric oxide and biogenic amines. OVA-treated mice were found to reproduce some of the important hallmarks of human asthma 24 and 72 hours after allergen challenge including infiltration of eosinophils and lymphocytes only in the chronic model , high serum levels of total IgE and OVA-specific IgG and evidence of plasma protein extravasation. Some other hallmarks, such as AHR, eosinophil degranulation and nitric oxide production could not be demonstrated, but their absence in the novel murine models cannot yet be confirmed for certain and alternative techniques were suggested for their determination. In addition, the novel chronic model exhibited gender differences which reflect the human situation where adult women are more susceptible to asthma than men, and could be used to investigate the role of sex hormones in asthma and their potential use as anti-asthma therapies. Mice have advantages over other species because their immune system is well characterized and knockout and transgenic mice are available. The acute murine model will be useful for investigation of the inflammatory and functional changes associated with the first few days of the asthma process. In contrast, the chronic model will be employed for investigation of airway wall remodelling and subsequent respiratory alterations.

The inhalation of poorly soluble particles such as synthetic resin polymers is characterised by a series of biochemical and histopathological responses in the lung. These responses can be characterised as acute and chronic pathologies that include pulmonary oedema, inflammation and fibrosis. The ability correctly to identify patients that manifest early signs of lung injury could significantly reduce the morbidity from these types of pathologies. Consequently, this study was undertaken to identify protein markers of early oedema and inflammation. Models of pulmonary injury were induced in the rat lung via intratracheal instillation of a synthetic resin polymer. Conventional quantitative analysis of broncho-alveolar lavage (BAL) fluid was used to indicate the severity of the oedematous response, whilst morphological changes were identified by histological examination. Two dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (2D SDS PAGE) was then employed to separate the proteins in the BAL fluid collected from the mild and persistent models of lung injury. The complete toxicological and histological characterisation of the polymer- induced model of pulmonary injury successfully identified specific endpoints of injury. This model was used to study the protein profiles in response to polymer-induced lung injury. 2D SDS PAGE was optimised for use with BAL fluid and identified two interesting proteins, prosaposin and calgranulin A, which have the potential to act as biomarkers for lung injury. Furthermore, immunohistochemistry can provide an insight into co-localization and quantitative analysis of proteins identified by proteomics with cellular organisation/structure, which in turn, may be reflective of their function. This was demonstrated using two proteins, cocoacrisp and surfactant protein A that were found to have elevated levels in tissue sections from the polymer treated lungs. Finally, in addition to all these proteins being potential biomarkers of lung injury, they are also prospective targets for clinical treatment.

The public, as the users of antibiotics, can contribute to the control of bacterial resistance. National and international campaigns have recommended public education to promote the judicious and safe use of antibiotics, and in particular, reducing antibiotic use and misuse in upper respiratory tract infections. Campaigns, however, have not been informed by detailed understanding of public attitudes to the problem. Although previous studies have explored lay perceptions of common infections and antibiotics, public attitudes to bacterial resistance, beliefs about antibiotic use in relation to bacterial resistance and the attitudes towards respiratory tract infection influencing antibiotic use are under researched. This thesis addresses this gap using a grounded theory approach. Semi-structured interviews with members of community groups were conducted across South East Wales. By analysing patterns and connections between various beliefs this thesis shows that historical antecedents and beliefs about dirt and germs act as prototypes for current beliefs about resistant infection. Most respondents did not feel that they have a personal role in either the cause or control of bacterial resistance. Lay beliefs about aetiology resided in both traditional and biomedical models. There was a reliance on medicines, and specifically antibiotic attachment, which contributed to self-medication and expectations for antibiotics during upper respiratory tract infection (URTI). Promoting public engagement in the control of bacterial resistance requires a number of approaches to behavioural change. In relation to antibiotic use efforts to promote adherence to antibiotic regimes need to address beliefs about antibiotics, forgetfulness and practical barriers to adherence but also to reduce public expectations for antibiotics for upper respiratory tract infections by enhancing understanding about the microbial causes of URTI. Efforts to reduce antibiotic use, however, need also to address the wider meaning and the reliance on antibiotics. Public engagement in the control of infection through hand washing should be promoted as an effective way to reduce the risk community acquired resistant infection.

Asthma is a chronic inflammatory disease characterised by airway inflammation, bronchoconstriction, airway hyperresponsiveness AHR and airway remodelling. Most models of asthma focus on acute allergen challenges, where airway remodelling is absent. The thesis aimed to compare acute and chronic allergen challenge models of asthma and analyse the effects of anti-inflammatory drugs on these models. Acute and chronic challenges with ovalbumin in conscious guinea pigs and mice caused impared lung function, measured as specific airway conductance sGaw and enhanced pause Penh , respectively. This was characterised by early EAR and late LAR asthmatic responses, AHR and cellular influx. Multiple challenges with ovalbumin caused airway remodelling distinguished by increased bronchiolar collagen and goblet cells compared to control. No airway remodelling was observed in acute ovalbumin models. Treatment with the corticosteroid, fluticasone propionate FP, attenuated the LAR, AHR and cellular influx in all models. In both chronic ovalbumin models, FP treatment partially reversed airway remodelling, though not to naive levels. This was also the case with treatment with the phosphodiesterase IV inhibitor, roflumilast. However, roflumilast also attenuated the EAR. Treatment with the iNOS inhibitor, GW274150F, reduced the LAR and AHR and showed some inhibition of cellular influx in the acute ovalbumin challenged animals. However, GW274150F was ineffective in chronic ovalbumin models. Lung oedema, assessed by magnetic resonance imaging in acute and chronic ovalbumin challenged guinea pigs, was increased and correlated temporarily with the LAR. Dexamethasone treatment attenuated the level of oedema though not to control levels. Acute ovalbumin challenged models showed airway functional changes which were partially resolved with drug treatment. Chronic ovalbumin challenges provoked lung functional and structural changes which were attenuated by FP and roflumilast but not GW274150F. As GW274150F proved ineffective in clinical trials, the data in this thesis suggests that chronic ovalbumin challenge animals are better pre-clinical models of asthma.

It was hypothesized that Respiratory heat and moisture loss (RHML) would be altered in patients with Asthma and Chronic obstructive pulmonary disease (COPD) due to the effects of airway inflammation and re-modeling. By designing a novel device incorporating humidity, temperature and flow sensors, RHML was measured in 25 normal controls, 33 asthmatics and 17 patients with COPD. In normal subjects RHML was found to be dependent on breathing pattern as defined by tidal volume and minute ventilation whereas no association was found between RHML and body surface area. At matched breathing patterns asthmatics whether in the exacerbation or stable group showed a small but significantly increased RHML compared to controls (exacerbation group-93.2 (SD=8.0), p=0.0003, stable group - 89.3 (SD=7.4), p=0.025 and controls 85 (SD=4.3) Joules/L). No significant difference was found in RHML between the asthmatics with an exacerbation and those with stable disease. COPD patients showed no significant difference in RHML (stable group-83 (SD=4.8), p=0.23 and exacerbation group-81 (5D=5.8), p=0.06 Joules/L) compared to controls or between exacerbation and stable groups. Evaporative heat loss accounted for the major heat transfer modality (up to 3-times the dry convective heat loss). It can be concluded that asthma is associated with a measurable increase in heat and moisture loss in breath and that this may reflect the inflammatory and vascular changes known to occur in the asthmatic airway. Further studies are required to assess whether the technique developed in this study may provide a practical means to measure inflammation in asthma.

Methods: Patients with stable symptomatic chronic heart failure were screened for sleep-disordered breathing by home sleep study. Daytime sleepiness was assessed by Epworth Sleepiness Scale and heart failure severity by symptom class, left ventricular ejection fraction and serum N-terminal pro-brain natriuretic peptide concentrations. In a subset of patients, synchronous in-laboratory limited sleep studies and polysomonography, and home limited sleep studies, were performed prospectively. Patients with obstructive sleep apnoea and stable symptomatic chronic heart failure were randomised to nocturnal auto-titrating continuous positive airway pressure or sham for six weeks each in crossover design. Results: In the era of modern therapy, sleep-disordered breathing is common in patients with stable symptomatic chronic heart failure, predominantly obstructive in aetiology, without clear relationship to heart failure severity and is difficult to diagnose because of major overlap in symptomatology. Limited sleep studies compare well diagnostically to polysomnography when tested under identical patient and environmental conditions but less so when tested in the home setting. Auto-titrating continuous positive airway pressure improves daytime sleepiness is patients with obstructive sleep apnoea and chronic heart failure but not other subjective or objective measures of heart failure severity. Conclusions: Sleep-disordered breathing is difficult to detect clinically in patients with chronic heart failure, and as such, the diagnosis is reliant on accurate sleep studies. However, the clinical utility of limited sleep studies in detection and diagnosis of sleep-disordered breathing is restricted by a number of technical and situational factors which are exacerbated in patients with chronic heart failure. The potential therapeutic benefits of continuous positive airway pressure in patients with obstructive sleep apnoea and chronic heart failure are achieved by alleviation of obstructive sleep apnoea rather than by improvement in cardiac function.