SURFACTANT PHYSICOCHEMICAL PROPERTIES & AIRWAY PATENCY

描述：（改编自申请人的摘要） 本研究旨在探讨表面活性剂 物理化学性质、机械应力和流体平衡 存在于肺气道开放过程中， 被液体阻塞物堵塞或者塌陷。 这些物理化学 性质被假定为关键的决定因素：1）压力 开放气道所需的机械应力; 2）引起的机械壁应力 在打开期间; 3）保持在所述开口内的流体的体积 开放后气道; 4）气道开放的均匀性;和5） 支气管树的稳定性。 四个具体目标将调查 这些假设。 为了验证表面活性剂物理- 化学性质（强度、溶解度和吸附率）决定 界面应力，并确定本构形式 描述这种关系的方程， 简单和复杂表面活性剂溶液中的振荡气泡将 与来自振荡的计算模型的预测相比， bubble. 接下来，用毛细管模型清除阻塞的气道。 将研究含有模型表面活性剂的流体。 的 压力、衬膜厚度与表面活性剂的关系 将使用物理化学性质来估计那些表面活性剂 降低对大驱动压力的需求并稳定 气道衬里液体。 灵活的单气道和分叉气道模型 将被用来研究物理化学性质， 瞬态压力的大小和均匀性， 可以打开支气管树。 最后，切除的肺实验 将被用来评估表面活性剂的性质对 单次和多次坍塌的压力和稳定性特征 航空公司. 所有研究均采用单次和多次- 组分模型表面活性剂和外源表面活性剂替代物。 的 拟议的工作将解释存在的基本力量平衡， 婴儿第一次呼吸时的肺部系统 这项工作将 预测外源表面活性剂的物理化学性质， 使在打开期间施加到气道的机械应力最小化 患有呼吸窘迫综合症的肺部 （RDS）。这项工作还将阐明发生在 在疾病状态下常见的塌陷或闭塞的气道的重新开放 例如肺气肿、哮喘和囊性纤维化，因此可能提示新 这些疾病的治疗策略。

DESCRIPTION: (Adapted from the applicant's abstract) The objective of this research is to investigate the relationships between surfactant physico-chemical properties and the mechanical stress and fluid balances that exist during the opening of pulmonary airways that are either collapsed or occluded by fluid obstructions. These physico-chemical properties are postulated to be the key determinants of: 1) the pressure needed to open the airways; 2) the mechanical wall stresses induced during opening; 3) the volume of fluid that is retained within the airway after opening; 4) the uniformity of airway opening; and 5) the stability of the bronchial tree. Four specific aims will investigate these hypotheses. To test the hypothesis that surfactant physico- chemical properties (strength, solubility and adsorption rate) dictate interfacial stresses, and to determine the forms of constitutive equations that describe this relationship, the pressures required to oscillate bubbles in simple and complex surfactant solutions will be compared with predictions from a computational model of an oscillating bubble. Next, clearance of capillary-tube model airways occluded with fluids containing model surfactants will be investigated. The relationships between the pressure, film lining thickness and surfactant physico-chemical properties will be used to estimate those surfactant properties that reduce the need for large driving pressures and stabilize the airway lining fluid. Flexible single and bifurcating airway models will be used to study the physico-chemical properties that affect both the magnitude of the transient pressure and the uniformity with which the bronchial tree can be opened. Finally, excised lung experiments will be used to evaluate the influence of surfactant properties on the pressures and stability characteristics of single and multiple collapsed airways. All studies will be conducted with single- and multiple- constituent model surfactants and exogenous surfactant substitutes. The proposed work will explain the fundamental force balances that exist in the pulmonary system during an infant's first breath. This work will predict exogenous surfactant physico- chemical properties that will minimize the mechanical stresses applied to airways during the opening of lungs that are afflicted with Respiratory Distress Syndrome (RDS).This work will also elucidate the force balances that occur during the reopening of collapsed or occluded airways common in disease states such as emphysema, asthma and cystic fibrosis, and may thus indicate new strategies for the treatment of these diseases.