Tidal stresses are thought to be involved in maintaining airway patency in vivo. The present study examined the effects of normal stresses exerted by the lung parenchyma during tidal ventilation on recovery from agonist-induced airway constriction. In seven anesthetized dogs, one lung was selectively ventilated with a Univent endotracheal tube (Vitaid, Lewiston, NY). Airway tone was increased e...

Pulmonary surfactant is a complex mixture of unique proteins and lipids that covers the airway lumen. Surfactant prevents alveolar collapse and maintains airway patency by reducing surface tension at the air-liquid interface. Furthermore, it provides a defence against antigen uptake by binding foreign particles and enhancing cellular immune responses. Allergic asthma is associated with chronic ...

Simultaneous measurement of input (Zin) and transfer impedances (Ztr) allows separation of airway and tissue properties at a single frequency, without making assumptions concerning the structure of the two compartments. This approach offers the possibility of studying the variation in airway impedance (Zaw) during the respiratory cycle. Zin and Ztr were measured at frequencies of 10, 20, 30 and...

Obstructive sleep apnea (OSA) is a major source of cardiovascular morbidity and mortality, and represents an increasing burden on health care resources. Understanding underlying pathogenic mechanisms of OSA will ultimately allow for the development of rational therapeutic strategies. In this article, we review current concepts about the pathogenesis of OSA. Specifically, we consider the evidenc...

STUDY OBJECTIVES High dose rate (HDR) endobronchial brachytherapy is widely used as a palliative treatment for symptomatic airway obstruction by primary or secondary malignant tumors. We report on a successful use of HDR brachytherapy in patients with nonmalignant airway obstruction. DESIGN Case series PATIENTS Six patients received HDR brachytherapy for airway obstruction caused by granula...

Although airway patency is partially maintained by parenchymal tethering, this structural support is often ignored in many discussions of asthma. However, agonists that induce smooth muscle contraction also stiffen the parenchyma, so such parenchymal stiffening may serve as a defense mechanism to prevent airway narrowing or closure. To quantify this effect, specifically how changes in parenchym...

Elastin synthesis and degradation in the airway and lung parenchyma contribute to airway mechanics, including airway patency and elastic recoil. IL-13 mediates many features of asthma pathobiology, including airway remodeling, but the effects of IL-13 on elastin architecture in the airway wall are not known. We hypothesized that IL-13 modulates elastin expression in airway fibroblasts from subj...

OBSTRUCTIVE SLEEP APNEA HYPOPNEA SYNDROME (OSAHS) IS A PREVALENT CONDITION THAT IS THOUGHT TO RESULT FROM DECREASED UPPER AIRWAY PATENCY IN SLEEP COMPARED TO WAKEFULNESS. In obstructive sleep-disordered breathing, the airway completely (apnea) or partially (hypopnea) occludes despite continued respiratory effort. Arousals from sleep temporarily restore upper airway patency, only to be followed ...