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Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma. As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is(More)
In this study, isovolumic bronchial segments and bronchial rings were used to investigate the influence of airway diameter on smooth muscle force generation and acetylcholine responsiveness. Segments with internal diameters ranging from 1.0-6.0 mm were obtained from the mainstem bronchus of eight pigs. Responses to increasing acetylcholine concentrations(More)
During bronchoconstriction elastic after-loads arise due to distortion of lung parenchyma by the narrowing airway. In the present study, the functional effect of parenchymal elastic after-load on airway narrowing was determined. Airway narrowing was measured in vivo over a range of transpulmonary pressures and compared with in vitro narrowing measured at(More)
Contraction of airway smooth muscle (ASM) is regulated by the physiological, structural and mechanical environment in the lung. We review two in vitro techniques, lung slices and airway segment preparations, that enable in situ ASM contraction and airway narrowing to be visualized. Lung slices and airway segment approaches bridge a gap between cell culture(More)
The observation that the length-force relationship in airway smooth muscle can be shifted along the length axis by accommodating the muscle at different lengths has stimulated great interest. In light of the recent understanding of the dynamic nature of length-force relationship, many of our concepts regarding smooth muscle mechanical properties, including(More)
DYNAMIC RESPIRATORY MOVEMENTS such as deep inspiration (DI) are believed to play an important role in limiting airway narrowing, and a failure of this physiological regulation is offered as a potential pathway to airway hyperresponsive-ness in asthma (1). While our understanding of the mecha-nism(s) involved is incomplete, beneficial effects of DI are(More)
Epithelial injury and bronchial hyperresponsiveness are commonly associated with airway disease, and are widely considered to occur as the result of inflammatory changes in the airway wall. Mechanistically, the airway epithelium may influence the sensitivity of the airways to provocative stimuli through its primary function as a cellular barrier between the(More)
A period of deep inspiration in humans has been shown to attenuate subsequent bronchoconstriction, a phenomenon termed bronchoprotection. The bronchoprotective effect of deep inspiration may be caused though a depression in the force production of airway smooth muscle (ASM). We determined the response of whole airway segments and isolated ASM to a period of(More)
In healthy individuals, deep inspiration produces bronchodilation and reduced airway responsiveness, which may be a response of the airway wall to mechanical stretch. The aim of this study was to examine the in vitro response of isolated human airways to the dynamic mechanical stretch associated with normal breathing. Human bronchial segments (n = 6) were(More)
Maturational changes in the specific compliance could potentially contribute to the development or clinical presentation of respiratory diseases in infants and children. Changes in the specific compliance during development and its structural basis have been well characterized, but changes in bronchial compliance and the mechanisms involved have received(More)