The Streptococcus pneumoniae-derived toxin, pneumolysin, has been reported to augment neutrophil-mediated inflammatory responses in murine models of experimental infection of the airways, and to favour invasive pneumococcal disease. The laboratory research presented in this thesis has been designed to investigate the possible proinflammatory interactions of pneumolysin with human neutrophils in vitro, as well as the underlying mechanisms of these. Addition of pneumolysin (0.0167 - 41.75 ng/ml) to neutrophils caused dose-related enhancement of the following proinflammatory activities of these cells: superoxide generation, elastase release, expression of the β2-integrin CR3, phospholipase A2 activity and production of leukotriene B4 and prostaglandin E2, oxidative inactivation of α-1-proteinase inhibitor, and synthesis and release of interleukin-8. Pneumolysin-mediated enhancement of these neutrophil activities was observed in the absence of detectable cytotoxicity and was most striking when the toxin was added together with the bacterial chemoattractant N-formyI-L-methionyl-L-leucyl-L-pnenylalanine (FMLP, 1 µM). Treatment of neutrophils with pneumolysin also resulted in uncontrolled influx of Ca2+ into the cells in the setting of membrane depolarisation and efflux of K+, which appeared to be a consequence of the pore forming actions of the toxin. Importantly, the proinflammatory interactions of pneumolysin with neutrophils were completely attenuated by exclusion of Ca2+ from the cell-suspending medium. These observations identify novel proinflammatory properties of pneumolysin which result from pore formation in the plasma membrane, influx of Ca2+ and augmentation of Ca2+ -activitable neutrophil functions. / Thesis (DPhil)--University of Pretoria, 2005. / Immunology / unrestricted

Obstructive Sleep Apnea (OSA) is becoming an increasingly prevalent health problem, affecting 4% of men and 2% of women in North America. OSA is associated with many debilitating side-effects and co-morbidities; the most common being excessive daytime sleepiness (EDS), which effects the majority of OSA sufferers. EDS is negatively associated with physical activity (PA) and exercise. As a result, EDS may decrease the levels of PA performed by OSA patients. Previous research has revealed that the OSA population engages in less physical activity than the average healthy population. Studies show that CPAP treatment positively impacts EDS, and therefore; may impact PA. The primary purpose of this study was to objectively measure OSA patients' PA levels prior to CPAP treatment and 8 weeks after treatment initiation to assess whether CPAP treatment' impacts PA levels.Actigraph GT 1 M measures PA was assessed at baseline (prior to CPAP) and 8-weeks after. initiation of CPAP treatment. At each time frame, cardiovascular., blood data, body composition, and maximal cycle ergometer exercise measures were obtained. Also, subjective questionnaires, 1 reflective of sleep apnea and 1 regarding PA, were completed by the subjects.Six male subjects with severe OSA (AHI = 41.2 ± 28.4 events/hr) started and completed the study. No significant changes occurred in PA, represented as steps/day nor mean activity counts/day, throughout the 8 weeks of CPAP treatment. Significant changes were found in diastolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, and Epworth sleepiness scale scores. No significant changes occurred in any other body composition, heart rate, systolic blood pressure, triglycerides, and blood glucose. Exercise parameters, total test time, peak Watts, and V02max trended toward an increase and maximal heart rate and blood pressure toward a decrease, but none changed significantly.In conclusion, these results demonstrated that 8 weeks of CPAP treatment was not successful in increasing PA levels of severe OSA patients. The OSA subjects were categorized as sedentary according to their steps/day. Compliance to CPAP could have been an issue with subjects' average nightly usage ranging from 1.85 – 6.6hours/night. Consequently, more research regarding OSA patients PA habits and CPAP treatments effects on PA should be investigated. / School of Physical Education, Sport, and Exercise Science

Airway hyperresponsiveness (AHR) is one of the primary features of allergic airways disease. Despite continuous allergen exposure atopic asthmatics do not develop progressively worsening AHR. The mechanism(s) that limit AHR are unknown. Two valid candidates are regulatory T cells (Treg) and antigen presenting cells (APC). Dendritic cells (DC) are the main APC within the airways. Presentation of allergens to T cells can result in the differentiation and expansion of different subsets of T cells including effector Treg cells. The precise role of Treg and DC in the attenuation of allergen-induced AHR remains unknown. The general aim of this thesis is to investigate mechanisms to limit AHR in a murine model of atopic asthma. Specific aims are to: 1. develop a murine model of allergen-induced attenuation of AHR, 2. determine the potential role of regulatory T cells (Treg) in allergen-induced AHR attenuation, and 3. determine the potential role of airway dendritic cells (DC) in allergen-induced AHR attenuation. Balb/c mice were sensitised with intraperitoneal Ovalbumin (OVA) in aluminium hydroxide and challenged with a single, 3-weeks or 6-weeks of OVA aerosols. Aerosols were 1% OVA in sterile saline delivered for 30 minutes for three days per week. Animals were sacrificed 24 hours after the final aerosol for measurements of lung function and Methacholine (MCh) responsiveness (low-frequency forced oscillation technique), collection of bronchoalveolar lavage fluid (BALF) and serum. '...' In contrast, 6-weeks of OVA challenges decreased Treg numbers back to control levels. Adoptive transfer of 1x106 Treg taken from DLN of 3-week challenged mice attenuated AHR in single-OVA recipients (p<0.05). Furthermore, in vivo depletion of Treg in 3-week OVA challenged mice restored AHR (p<0.05 compared with control). Similar proportions of CD4+ T cells became activated following both aerosol regimes, however total numbers of airway CD4+ T cells were decreased (p<0.05), and OVA-specific CD4+ T cell proliferation in DLN was reduced (p<0.05) after 3-weeks versus one OVA aerosol. Analysis of antigen handling by airway APC populations showed antigen uptake (OVA-647) and processing (DQ-OVA) by macrophages and airway DC subsets to be down-regulated (p<0.05) after 3-weeks of OVA aerosols. In addition, adoptive transfer of Treg into single-OVA recipients did not affect antigen handling by airway APC populations. These data suggest that Treg are responsible for allergen-induced attenuation of AHR in vivo in established airways disease. AHR attenuation was associated with an altered function of airway DC, resulting in reduced antigen capture and processing, leading to limited clonal expansion of antigen-specific CD4+ T cells with limited production of Th2 cytokines. Furthermore, Treg were not directly responsible for the down-regulation of allergen capture in the airways. In conclusion, knowledge of the role of Treg and DC in attenuation of AHR could potentially result in improved and more directed therapies for the attenuation of AHR in atopic asthmatics.

Abstract not available

"May 2002." Bibliography: leaves 123-144. Aspects of the control of ventilation and an upper airway dilator muscle (genioglossus) are compared between healthy men and women, in an attempt to identify a gender difference that may contribute to the high male prevalence of sleep apnea.

[Tuncated abstract] There has been longstanding concern over whether endobronchial biopsies adequately represent inflammation throughout the bronchial tree in diseases such as asthma, despite the endobronchial biopsy technique having been used frequently to assess airway inflammation in research settings. There has also been ongoing debate about whether endobronchial biopsies should be assessed by new, unbiased, three-dimensional (3D) stereological techniques instead of traditional, two-dimensional (2D) non-stereological techniques. Therefore, the aims of this study were: (i) to investigate whether endobronchial biopsies represent the density of mast cells in the large and small airways, in alveolar walls and in the lung as a whole (ii) to use both stereological and non-stereological methods to address this question, and where possible, to compare the results of these two approaches. '...' Mast cell density in biopsies was not related to mast cell density immediately adjacent to the biopsy site or to mast cell density in the total airway wall in the large airways, the inner airway wall in the small airways, the walls of the alveoli or the lung as a whole. In general, measurements of mean mast cell density on biopsies to a depth of 100µm below the basement membrane were poorly related to mean mast cell density in other compartments of the lung. Mean 3D and 2D mast cell densities were strongly correlated (r 0.9, p < 0.005) and where both methods were used, results were similar. The mean height and area profile of a mast cell were approximately 12µm and 68µm2 respectively. In disk-shaped IUR lung samples, percent shrinkage in height due to paraffin processing was systematically greater than percent radial shrinkage by an average of approximately 4 times. Cavalieri lung volumes were systematically smaller than displacement volumes by an average of 14%. Any given endobronchial biopsy is unlikely to represent mast cell density around the airway wall generally in the vicinity of the biopsy site. However, the average of at least 4 biopsies from different sites in the proximal airways can be used to both represent mean mast cell density in the inner airway wall of the large airways, and act as the basis for inter-subject comparisons of mean mast cell density in the total airway wall of the small airways. On biopsies, mast cell counts should be measured over the entire inner airway wall not just to a depth of 100µm or less below the basement membrane. 3D mast cell densities obtained by stereological methods are closely related to 2D mast cell densities obtained by non-stereological methods and are likely to result in similar conclusions. Lung volumes are smaller when measured by the Cavalieri method than when measured by fluid displacement. Shrinkage of isotropic uniform random samples of human lung tissue due to paraffin processing is anisotropic. The mean volume of a mast cell in the human lung is likely to be much smaller than that reported previously for monkey lungs.

Thesis (Ph.D.)--University of Western Australia, 2008.

Utilization of airway protective rehabilitation among individuals with neurodegenerative disease is astoundingly low. Yet, due to progressive decline in airway protective function and resulting health consequences such as aspiration pneumonia, the need for rehabilitation is clear. Moreover, a growing literature supports the benefit of airway protective rehabilitation in neurodegenerative populations. Therefore, it is a healthcare priority to increase treatment utilization in order to improve health and quality of life for individuals with neurodegenerative disease. Improving treatment accessibility and relevance are two approaches that have the potential to improve utilization. Despite the need to increase treatment accessibility and the growing evidence base to support the use of telehealth to increase access, a significant gap remains in our understanding of the feasibility and acceptability of telehealth to manage dysphagia in neurodegenerative disease. Moreover, little is known about patient perspectives which are critical to refine person-centered models of care that are relevant to patient’s needs. To address this important clinical research gap, this dissertation includes a series of three research studies aimed at improving accessible and relevant rehabilitation for airway protective dysfunction in neurodegenerative disease. Chapter 1 will provide an overview of the current literature as it relates to airway protective dysfunction in neurodegenerative disease, existing rehabilitation approaches, telehealth to manage dysphagia, and the need for personalized care. Chapter 2 will examine the feasibility of rehabilitating airway protection via telehealth in individuals with neurodegenerative movement disorders. Chapter 3 will then explore speech language pathologists’ (SLPs) perspectives and experiences using telehealth to manage dysphagia. Chapter 4 will characterize patient perspectives on airway protective dysfunction and treatment experience following cough skill training (CST). I will conclude (Chapter 5) by synthesizing the findings from chapters 2-4 and suggesting directions for future research.

[Truncated abstract] Asthma genetic studies have identified many genes that contribute to the pathogenesis of asthma and related variables. Members of the secretoglobin family appear to play an important role in controlling airway inflammation but they have received relatively little attention in asthma genetic research. In this thesis, I have investigated the genes of two members of the secretoglobin family (16 kDa Clara cell secretory protein (CC16) and secretoglobin 3A2 (SCGB3A2)) that are expressed at high levels in the airways and are important anti-inflammatory agents. The overall aim of these studies was to investigate the genetic variability of the CC16 and SCGB3A2 genes and their influence on airway inflammatory disease. The main hypothesis was that genetic variability in the genes for CC16 and SCGB3A2 exert an influence on airway inflammatory disease. Three populations were investigated: (1) a paediatric case control population (n=99), (2) an unselected birth cohort followed longitudinally at ages 1 month (n=244), six (n=123) and 11 years (n=195) and (3) an unselected Aboriginal Australian population (n=251). The case-control population was screened for novel DNA sequence variants in the CC16 promoter and the SCGB3A2 5’UTR and exons. No novel sequence variants were identified in the CC16 promoter and two were identified in the SCGB3A2 5’UTR (G- 811A and G-205A). A single nucleotide polymorphism previously identified in the CC16 gene (A38G) and the two polymorphisms identified in the SCGB3A2 gene were genotyped in both unselected populations. Genotype/phenotype associations were identified with adjustment for potential confounders such as age, gender, height and maternal tobacco smoking, where appropriate. This was due to the contribution of these factors to the aetiology of asthma, atopy and related phenotypes. All three polymorphism frequencies were significantly different between these two ethnically diverse populations

This investigation aimed to objectively measure physiological deficiencies across the continuum of airway protection and clinical feeding and swallowing severity in children with spastic cerebral palsy (SCP), and to make comparisons with a healthy control group. Eleven children with SCP (GMFCS I-V) and 10 controls (mean age: 7+ 2 years) were tested. Results revealed significantly impaired oropharyngeal function and greater clinical feeding and swallowing severity for children with SCP. These children also demonstrated impaired respiratory-swallow coordination evidenced by frequent post-swallow inhalation across all bolus types. Reduced cough volume acceleration was also observed in children with SCP compared to controls. In the SCP group, significant correlations with clinical feeding and swallowing severity were observed with oral praxis and post-swallow inhalation. Additionally, clinical feeding and swallowing severity and peak expiratory flow rate were significantly correlated with gross motor function. This is the first study to objectively identify the co-occurrence of dysphagia and dystussia in children with SCP, and to quantify factors underlying these deficits. Future research should address functional deficits along the continuum of airway protection in both assessment and treatment paradigms in order to maximize the quality of life for this population.