Doctor of Philosophy / Department of Kinesiology / Craig A. Harms / The overall aim of this dissertation was to determine the impact of lifestyle (i.e. habitual and acute physical activity and diet), age, and sex on systemic and airway inflammation and oxidative stress. In study 1 (Chapter 2) we examined the impact of habitual physical activity level on the post-prandial airway inflammatory response following an acute bout of moderate intensity exercise. Results indicated that the mean exhaled nitric oxide (eNO; marker of airway inflammation) response increased for all groups at two hours post high-fat meal (HFM) (~6%) and returned to baseline by four hours post-HFM. However, there was a varying eNO response from baseline to four hours in the group that exercised in the post-prandial period compared to the group that remained sedentary. These findings suggest airway inflammation occurs after a HFM when exercise is performed in the post-prandial period, regardless of habitual physical activity level. In study 2 (Chapter 3) we investigated the post-prandial oxidative stress response to meals of varying calories and fat. Specifically, we assessed the post-prandial airway and systemic 8-isoprostane (a marker of oxidative stress) responses to meals with moderate-fat (8.5 kcal/kg of bodyweight) and high-fat content (17 kcal/kg of bodyweight) from baseline to six hours post-meal in a randomized crossover design. This study revealed that systemic 8-isoprostane increased from baseline to six hours post-meal (38.3%), but there was no difference between the moderate-fat meal (MFM) and HFM conditions. There were no changes in airway 8-isoprostane from baseline to six hours post-MFM or HFM, or between the MFM and HFM conditions. Lastly, in study 3 (Chapter 4), we were interested in examining 8-isoprostane responses in older adults, since 8-isoprostane has been reported to increase with age. Previous research also suggests that older women (OW) and older men (OM) have differences with regard to prevalence and severity of late-onset asthma. In this study, we sought to determine whether the airway 8-isoprostane response to a strenuous bout of exercise was different in OW compared to OM. A secondary aim was to determine whether post-exercise 8-isoprostane generation was correlated with decrements in lung function. Our results showed that the generation of 8-isoprostane from pre- to post-exercise increased ~74±77% in OW and decreased ~12±50% in OM. The decrease in 8-isoprostane generation was not correlated with improvements in lung function from pre- to post-exercise. These findings collectively contribute to the literature by enhancing our understanding of the impact of lifestyle factors, age and sex on modifying and potentially mitigating the risk of developing chronic diseases.

Rationale: Tissue Factor (TF) is a transmembrane glycoprotein that canonically functions as the initiator of the coagulation cascade. Increased levels of TF have been associated with inflammatory airway diseases. Since lipopolysaccharide (LPS) is known to elicit and inflammatory response in airway epithelium, we hypothesized that airway epithelial cells release TF when exposed to LPS. Since TF aids in local wound healing, we also hypothesized that inhibition of TF would decrease NHBE growth. The specific aim of this work was to evaluate the effects of LPS exposure on TF production and release from airway epithelia and determine the signaling pathways involved. A secondary aim was to evaluate the effects of TF inhibition on NHBE growth. Methods: Normal human bronchial epithelial cells were grown in submerged cell culture and exposed to LPS as well as several intracellular signaling pathway agonist and inhibitors. Measurements: Tissue Factor mRNA and protein were measured in culture media and cell lysate by reverse-transcriptase polymerize chain reaction and enzyme-linked immunosorbent assay, respectively. Signaling pathways were evaluated using selective agonists and inhibitors. Main results: TF protein levels increased nearly two-fold in cell media after exposure to LPS (p < 0.01). This did not occur in the presence of an MEK/ERK inhibitor (PD98059) or a SMAD inhibitor (SB431542). TF protein levels also increased nearly ten-fold in the presence of TGF-beta (p < 0.05). mRNA of TF and TGF-beta was not altered by LPS or TGF-beta exposure. NHBE grown in the presence of Tissue Factor Pathway Inhibitor grew significantly slower than those grown in standard media (P < 0.05). Conclusions: NHBE release TF when exposed to LPS. This phenomenon is post-translational and may be mediated by an autocrine mechanism involving MEK/ERK signaling that increases TGF-beta which then leads to the release of TF. Our data suggest that this airway epithelium release of TF serves as a local repair function.

Background: Asthma is a heterogeneous disease. Diagnosis relies on symptom evaluation and lung function tests using spirometry. Symptoms can be vague. Spirometry is effort-dependent and does not reliably evaluate small airways. Allergic asthma in preschool children is not easily separated from episodic wheeze. Exhaled NO (FeNO) is a marker of allergic Th2-cytokine-driven airway inflammation. However, FeNO is not feasible in preschoolers with current devices and algorithms. Alveolar NO is an estimate of small airway involvement. Forced oscillometry (FOT) is an effort-independent lung function test assessing both large and small airways. Aims: To study clinical and methodological aspects of FeNO, alveolar NO and lung function indices by FOT. Methods: Asthmatic children and young adults and healthy controls, were included in the studies. FeNO at 50 mL/s was performed in all studies (in study III with an adapted single-breath method with age-adjusted exhalation times). FeNO at multiple exhalation flow rates were performed in studies I, II and IV to calculate alveolar NO, as was spirometry. FOT indices were assessed in study IV. Results: The exhalation time needed to reach steady-state NO was &lt; 4 s in subjects aged 3-4 years, and was related to subject height. FeNO was higher in ICS-naïve asthmatic children than in controls. ICS-naïve asthmatic preschool children had FeNO &lt; 20 ppb. The oral contribution to FeNO was similar in asthmatic and healthy youths. Multiple flow rates and modelling of alveolar NO were feasible in children aged 10-18 years. Alveolar NO correlated to asthma characteristics, though not when axial diffusion correction was applied. FOT resistance measures were associated with asthma diagnosis, and small airway FOT measures were associated with asthma control, in adolescents. Conclusion: An adapted FeNO method is feasible from 4 years, and exhalation time is related to child height. Our findings emphasise the need to refine clinical cut-offs for FeNO in younger children. FOT variables discriminate between asthmatics and controls, much like spirometry. The information provided by FOT is additive to that from spirometry. Further studies of exhaled NO dynamics and FOT indices of small airways are warranted to evaluate new treatment options and possibly improve asthma control.

Objetivos: Comparar os efeitos dos tratamentos com montelucaste e dexametasona no recrutamento eosinofílico e na avaliação de células positivas para eotaxina, RANTES, fibronectina, IGF-I e NF-B tanto no parênquima pulmonar distal, quanto nas vias aéreas de cobaias com inflamação alérgica crônica. Métodos: As cobaias receberam inalação com ovoalbumina (grupo OVA- 2 vezes semanais, durante 4 semanas, totalizando 7 inalações). Após a quarta inalação, as cobaias foram tratadas com montelucaste (grupo OVA-M: 10mg/Kg/VO/dia) ou dexametasona ( grupo OVA-D: 5mg/Kg/IP/dia). Após 72 horas da sétima inalação, as cobaias foram anestesiadas e os pulmões foram removidos e submetidos a avaliação histopatológica. Resultados: Os tratamentos com montelucaste e dexametasona reduziram o número de eosinófilos tanto no parênquima pulmonar distal quanto nas vias aéreas, quando comparados ao grupo OVA (p<0.05). No parênquima pulmonary distal, ambos os tratamentos foram efetivos na redução de células positivas para RANTES, NF-B e fibronectina, quando comparados ao grupo OVA (p<0.001). O tratamento com montelucaste mostrou melhor eficácia na redução de células positivas para eotaxina, quando comparado ao tratamento com dexametasona (p<0.001), por outro lado, o tratamento com dexametasona mostrou-se mais significativo na redução de células positivas para IGF-I, quando comparado ao tratamento com montelucaste (p<0.001). Nas vias aéreas, ambos os tratamentos foram efetivos na redução de células positivas para IGF-I, RANTES e fibronectina, quando comparados ao grupo OVA (p<0.05). O tratamento com dexametasona foi mais efetivo na redução de células positivas para eotaxina e NF-B, quando comparado ao tratamento com montelucaste (p<0.05). Conclusões: Neste modelo animal, ambos os tratamentos foram efetivos no controle da resposta inflamatória, tanto no parênquima pulmonar distal, quanto nas vias aéreas / Aims: Compare the effects of montelukast or dexamethasone treatments on eosinophilic recruitment, eotaxin, RANTES, fibronectin, IGF-I and NF-B positive cells of distal lung parenchyma and also in airway walls of guinea pigs (GP) with chronic allergic inflammation. Methods: GP were inhaled with ovalbumin (OVA group-2x/week/4weeks). After 4th inhalation, GP were treated with montelukast (M group: 10mg/Kg/PO/day) or dexamethasone (D group: 5mg/Kg/IP/day). After 72 hrs of 7th inhalation, GP were anesthetised, lungs were removed and submitted to histopathological evaluation. Results: Montelukast and dexamethasone treatments reduced the number of eosinophils both in airway wall as well as in distal lung parenchyma compared to OVA group (p<0.05). On distal parenchyma both montelukast and dexamethasone were effective in reducing RANTES, NF-B and fibronectin positive cells compared to OVA group (p<0.001). Montelukast was more effective in reducing the eotaxin positive cells on distal parenchyma compared to dexamethasone treatment (p<0.001), while there was a more expressive reduction of IGF-I positive cells in OVA-D group (p<0.001). On airway walls, both montelukast and dexamethasone were effective in reducing IGF-I, RANTES and fibronectin positive cells compared to OVA group (p<0.05). Dexamethasone was more effective reducing the number of eotaxin and NF-kB positive cells than Montelukast (p<0.05). Conclusions: In this animal model, both treatments were effective in modulating the eosinophilic response in distal lung parenchyma and in airway wall, contributing to a better control of the inflammatory response in distal lung parenchyma as well as in airway walls. Dexamethasone treatment induced a greater reduction of NF-B expression in airway walls which suggests one of the mechanisms that explains the higher efficacy of this therapeutic approach

Objetivos: Comparar os efeitos dos tratamentos com montelucaste e dexametasona no recrutamento eosinofílico e na avaliação de células positivas para eotaxina, RANTES, fibronectina, IGF-I e NF-B tanto no parênquima pulmonar distal, quanto nas vias aéreas de cobaias com inflamação alérgica crônica. Métodos: As cobaias receberam inalação com ovoalbumina (grupo OVA- 2 vezes semanais, durante 4 semanas, totalizando 7 inalações). Após a quarta inalação, as cobaias foram tratadas com montelucaste (grupo OVA-M: 10mg/Kg/VO/dia) ou dexametasona ( grupo OVA-D: 5mg/Kg/IP/dia). Após 72 horas da sétima inalação, as cobaias foram anestesiadas e os pulmões foram removidos e submetidos a avaliação histopatológica. Resultados: Os tratamentos com montelucaste e dexametasona reduziram o número de eosinófilos tanto no parênquima pulmonar distal quanto nas vias aéreas, quando comparados ao grupo OVA (p<0.05). No parênquima pulmonary distal, ambos os tratamentos foram efetivos na redução de células positivas para RANTES, NF-B e fibronectina, quando comparados ao grupo OVA (p<0.001). O tratamento com montelucaste mostrou melhor eficácia na redução de células positivas para eotaxina, quando comparado ao tratamento com dexametasona (p<0.001), por outro lado, o tratamento com dexametasona mostrou-se mais significativo na redução de células positivas para IGF-I, quando comparado ao tratamento com montelucaste (p<0.001). Nas vias aéreas, ambos os tratamentos foram efetivos na redução de células positivas para IGF-I, RANTES e fibronectina, quando comparados ao grupo OVA (p<0.05). O tratamento com dexametasona foi mais efetivo na redução de células positivas para eotaxina e NF-B, quando comparado ao tratamento com montelucaste (p<0.05). Conclusões: Neste modelo animal, ambos os tratamentos foram efetivos no controle da resposta inflamatória, tanto no parênquima pulmonar distal, quanto nas vias aéreas / Aims: Compare the effects of montelukast or dexamethasone treatments on eosinophilic recruitment, eotaxin, RANTES, fibronectin, IGF-I and NF-B positive cells of distal lung parenchyma and also in airway walls of guinea pigs (GP) with chronic allergic inflammation. Methods: GP were inhaled with ovalbumin (OVA group-2x/week/4weeks). After 4th inhalation, GP were treated with montelukast (M group: 10mg/Kg/PO/day) or dexamethasone (D group: 5mg/Kg/IP/day). After 72 hrs of 7th inhalation, GP were anesthetised, lungs were removed and submitted to histopathological evaluation. Results: Montelukast and dexamethasone treatments reduced the number of eosinophils both in airway wall as well as in distal lung parenchyma compared to OVA group (p<0.05). On distal parenchyma both montelukast and dexamethasone were effective in reducing RANTES, NF-B and fibronectin positive cells compared to OVA group (p<0.001). Montelukast was more effective in reducing the eotaxin positive cells on distal parenchyma compared to dexamethasone treatment (p<0.001), while there was a more expressive reduction of IGF-I positive cells in OVA-D group (p<0.001). On airway walls, both montelukast and dexamethasone were effective in reducing IGF-I, RANTES and fibronectin positive cells compared to OVA group (p<0.05). Dexamethasone was more effective reducing the number of eotaxin and NF-kB positive cells than Montelukast (p<0.05). Conclusions: In this animal model, both treatments were effective in modulating the eosinophilic response in distal lung parenchyma and in airway wall, contributing to a better control of the inflammatory response in distal lung parenchyma as well as in airway walls. Dexamethasone treatment induced a greater reduction of NF-B expression in airway walls which suggests one of the mechanisms that explains the higher efficacy of this therapeutic approach

BACKGROUND: Older individuals suffer from higher rates of pulmonary infections than younger individuals. In addition, older individuals have increased morbidity and mortality due to pulmonary infections when compared to younger individuals. The physiological and immunological reasons for these aforementioned differences are not clear. Recently, non-invasive markers of the lung's physiologic and immunologic status have been recognized. This study employs one of these non-invasive markers, exhaled nitric oxide, in an attempt to determine how the airways may change with age, predisposing older individuals to pulmonary diseases and poorer outcomes as compared to younger individuals. METHODS: Exhaled nitric oxide measurements were obtained from a group of 25 older subjects (61 to 79 years old, median 72 years old) and a group of 23 younger subjects (21 to 30 years old, median 24 years old) that were non-smokers with no history of pulmonary disease, no recent respiratory infections, and no history of environmental allergies. A focused history and physical exam along with spirometry were used to confirm the normal pulmonary status of each subject. Exhaled nitric oxide was measured following the American Thoracic Society recommendations using the Sievers Nitric Oxide Analyzer 280i. The exhaled nitric oxide values for the old and young groups were compared using the Wilcoxon Rank Sum test. RESULTS: For the older subjects, the median exhaled NO concentration was 36.9 ppb. For the younger subjects, the median exhaled NO concentration was 18.7 ppb. These exhaled NO concentrations are significantly different (p = 0.0011). CONCLUSIONS: The exhaled NO concentrations are significantly higher in older individuals than in younger individuals. The reasons for this difference along with the significance are unclear and further studies will be necessary to further evaluate these issues.

Master of Science in Medicine / Rationale: Asthma management aims to achieve optimal control on the minimal effective dose of medication. We assessed the effectiveness of two algorithms to guide ICS dose in well-controlled patients on ICS+LABA in a double-blind study, comparing dose adjustment guided by exhaled nitric oxide (eNO) to clinical care algorithm(CCA) based on symptoms and lung function. Methods: We randomised non-smoking adult asthmatics on minimum FP dose 100μgs daily +LABA to ICS adjustment using eNO or CCA, assessed over 5 visits during 8 months treatment. Primary endpoints were asthma-free days and asthma related quality of life (QOL). Analysis was by mixed model regression and generalised estimating equations with log link. Results: 69 subjects were randomised (eNO:34, CCA:35) and 58 completed the study. At baseline mean FEV1 was 94% pred., mean eNO (200ml/sec) 7.1 ppb, median ACQ6 score 0.33. Median ICS dose was 500 μg (IQR 100-500) at baseline and 100 μg on both eNO (IQR 100-200) and CCA arms (IQR 100–100) at end of study. There were no significant differences between eNO and CCA groups in asthma-free days (RR=0.92, 95% CI 0.8–1.01), AQL (RRAQL<median = 0.95, 95% CI 0.8–1.1) or exacerbation-free days (HR = 1.03, 95%CI 0.6–1.7). Neither clinic FEV1 (overall mean difference FEV1 % pred. -0.24%, 95% CI -2.2–1.7) nor a.m. PEF (mean difference 1.94 L/min (95% CI -2.9–6.8) were significantly different. Similar proportions of subjects were treated for ≥1 exacerbation (eNO: 50%, 95% CI 32.1–67.9; CCA: 60%, 95% CI 43.9–76.2). Conclusion: Substantial reductions in ICS doses were achieved in well controlled asthmatics on ICS+LABA, with no significant differences in outcomes between eNO or clinically based algorithms.

It is well established that air pollution has detrimental effects on both human health as well as the environment. Exposure to ozone and particulate matter pollution, is associated with an increase in cardiopulmonary mortality and morbidity. Asthmatics, elderly and children have been indicated as especially sensitive groups. With a global increase in use of vehicles and industry, ambient air pollution represents a crucial health concern as well as a political, economical and environmental dilemma. Both ozone (O3) and diesel exhaust (DE) trigger oxidative stress and inflammation in the airways, causing symptoms such as wheezing, coughing and reduced lung function. The aim of this thesis was to further examine which pro-inflammatory signaling pathways that are initiated in the airways by ozone, as compared to diesel exhaust. Furthermore, to study the effects of these two ambient air pollutants in a sequential exposure, thus mimicking an urban profile. In order to investigate this in healthy as well as asthmatic subjects, walk-in exposure chambers were utilized and various airway compartments were studied by obtaining induced sputum, endobronchial biopsies, or airway lavage fluids. In asthmatic subjects, exposure to 0.2 ppm of O3 induced an increase in the cytokines IL 5, GM-CSF and ENA-78 in the bronchial epithelium six hours post-exposure. The healthy subjects, however, displayed no elevations of bronchial epithelial cytokine expression in response to the ozone exposure. The heightened levels of neutrophil chemoattractants and Th2 cytokines in the asthmatic airway epithelium may contribute to symptom exacerbations following air pollution exposure. When examining an earlier time point post O3 exposure (1½ hours), healthy subjects exhibited a suppression of IL-8 as well as of the transcription factors NFκB and c-jun in the bronchial epithelium, as opposed to after filtered air exposure. This inhibition of early signal transduction in the bronchial epithelium after O3 differs from the response detected after exposure to DE. Since both O3 and DE are associated with generating airway neutrophilia as well as causing direct oxidative damage, it raises the query of whether daily exposure to these two air pollutants creates a synergistic or additive effect. Induced sputum attained from healthy subjects exposed in sequence to 0.2 ppm of O3 five hours following DE at a PM concentration of 300 µg/m3, demonstrated significantly increased neutrophils, and elevated MPO levels, as compared to the sequential DE and filtered air exposure. O3 and DE interactions were further investigated by analyses of bronchoalveolar lavage and bronchial wash. It was demonstrated that pre-exposure to DE, as compared to filtered air, enhances the O3-induced airway inflammation, in terms of an increase in neutrophil and macrophage numbers in BW and higher EPX expression in BAL. In conclusion, this thesis has aspired to expand the knowledge of O3-induced inflammatory pathways in humans, observing a divergence to the previously described DE initiated responses. Moreover, a potentially adverse airway inflammation augmentation has been revealed after exposure to a relevant ambient combination of these air pollutants. This provides a foundation towards an understanding of the cumulative airway effects when exposed to a combination of ambient air pollutants and may have implications regarding future regulations of exposure limits.

Air pollutants, such as ozone (O3) and diesel exhaust particles, elicit oxidative stress in the lung. Antioxidants within the respiratory tract lining fluid (RTLF) protect the underlying tissue from oxidative injury. Supplementation with vitamins has been shown to modulate the acute ozone-induced effects, but the mechanisms behind this have not been fully clarified. The aim of this thesis was to investigate the airway responses to diesel exhaust and ozone exposure in healthy humans, with the emphasis on inflammatory and antioxidant responses. Furthermore, to study whether oral supplementation with vitamin C could increase ascorbate concentration in the RTLF and whether vitamin supplementation could modulate the negative effects induced by ozone exposure. Diesel exhaust (100 µg/m3 PM10 for 2h), evaluated 18 hours post exposure (PE), induced a neutrophilic airway inflammation and an increase in bronchoalveolar (BAL) urate and reduced glutathione. During O3 exposure (0.2 ppm for 2h), significant losses of nasal RTLF urate and ascorbate concentrations were observed. Six hours PE, a neutrophilic inflammation was evident in the bronchial wash (BW), together with enhanced concentrations of urate and total glutathione. In the bronchoalveolar lavage (BAL), where vitamin C, urate and glutathione concentrations were augmented, no inflammatory response was seen. In alveolar lavage leukocytes, there was a significant loss of glutathione and cysteine, whereas an increase in ascorbate was found in bronchial tissue samples. Following supplementation with increasing doses of vitamin C (60-1,000 mg/day, for 14 days), evaluated 24 hours after the last dose, ascorbate concentrations were unchanged in the nasal RTLF, despite elevated concentrations in plasma and urine. In contrast, following a single dose of 1g of vitamin C, vitamin C concentrations increased significantly in both plasma and nasal lavage two hours post supplementation, before returning to baseline levels at 24 hours. Notably, dehydroascorbate (DHA) accounted for the largest part of RTLF vitamin C and a number of control experiments were performed to ensure the authenticity of this finding. Healthy O3 responders were exposed to O3 (0.2 ppm for 2 h) and air, following seven days of supplementation with vitamin C and E or placebo. No protective effect on lung function or airway inflammation was observed following supplementation. BW and BAL-DHA were enhanced after O3, with further increases following supplementation. In conclusion, oxidative air pollutants induce airway inflammation, as well as a broad spectrum of antioxidant adaptations, which could ultimately limit the airway inflammatory responses. Oral vitamin supplementation was shown to augment RTLF-vitamin C concentrations, but it did not provide protection from the ozone-induced airway responses following a single insult of ozone. The finding of high concentrations of DHA in the RTLF could indicate that DHA represents an important transport form of vitamin C onto the surface of the lung.

Background: Ambient air pollution is associated with adverse health effects, but the sources and components, which cause these effects is still incompletely understood. The aim of this thesis was to investigate the pulmonary effects of a variety of common air pollutants, including diesel exhaust, biomass smoke, and road tunnel and subway station environments. Healthy non-smoking volunteers were exposed in random order to the specific air pollutants and air/control, during intermittent exercise, followed by bronchoscopy. Methods and results: In study I, exposures were performed with diesel exhaust (DE) generated at transient engine load and air for 1 hour with bronchoscopy at 6 hours post-exposure. Immunohistochemical analyses of bronchial mucosal biopsies showed that DE exposure significantly increased the endothelial adhesion molecule expression of p-selectin and VCAM-1, together with increased bronchoalveolar lavage (BAL) eosinophils. In study II, the subjects were exposed for 1 hour to DE generated during idling with bronchoscopy at 6 hours. The bronchial mucosal biopsies showed significant increases in neutrophils, mast cells and lymphocytes together with bronchial wash neutrophils. Additionally, DE exposure significantly increased the nuclear translocation of the aryl hydrocarbon receptor (AhR) and phosphorylated c-jun in the bronchial epithelium. In contrast, the phase II enzyme NAD(P)H-quinone oxidoreductase 1 (NQO1) decreased after DE. In study III, the 2-hour exposures took place in a road tunnel with bronchoscopy 14 hours later. The road tunnel exposure significantly increased the total numbers of lymphocytes and alveolar macrophages in BAL, whereas NK cell and CD56+/T cell numbers significantly decreased. Additionally, the nuclear expression of phosphorylated c-jun in the bronchial epithelium was significantly increased after road tunnel exposure. In study IV, the subjects were exposed to metal-rich particulate aerosol for 2 hours at a subway station with bronchial biopsy and BAL sampling at 14 hours. The subway exposure significantly increased the concentration of glutathione disulphide (GSSG) in BAL, with no airway inflammatory responses. In contrast, the number of neutrophils in the bronchial mucosa and the nuclear expression of phosphorylated c-jun in the bronchial epithelium tended to decrease after the subway exposure. In study V, the exposure to biomass smoke lasted 3 hours. Bronchoscopy was conducted 24 hours post exposure. The investigated biomass combustion emissions resulted in a significant increase in total glutathione and reduced glutathione in BAL, without any evident acute airway inflammatory responses.     Conclusion: The present thesis presents data from exposures of healthy subjects to a variety of common air pollutants, as compared with an air reference. Oxidative as well as bronchial mucosal and bronchoalveolar responses differed between these air pollutants, with the most pronounced airway effects seen after exposure to diesel exhaust. This may be due to differences in pulmonary deposition, physicochemical characteristics, toxicological pathways and potency. Additional studies will assist in addressing dose-response and time kinetic aspects of the airway responses.