SURFACTANT PHYSICOCHEMICAL PROPERTIES & AIRWAY PATENCY

描述：(改编自申请人的摘要)目标 本研究旨在探讨表面活性物质之间的相互关系。 物理化学性质与机械应力和流体平衡 在打开肺气道的过程中存在的 坍塌的或被液体阻挡住的这些物理化学物质 特性被认为是压力的关键决定因素：1)压力 需要打开呼吸道；2)机械壁应力 在打开过程中；3)保留在容器内的液体体积 开放后的通气口；4)通气口的均匀性；5)通气口的 支气管树的稳定性。四个具体目标将进行调查 这些假设。来检验表面活性物质物理- 化学性质(强度、溶解度和吸附速率)决定了 界面应力的确定和本构形式的确定 描述这种关系的方程，所需的压力 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进行比较 泡泡。下一步，毛细管状模型气道堵塞的间隙 将对含有模型表面活性剂的流体进行研究。这个 压力、膜层厚度与表面活性剂的关系 将使用物理化学性质来评估这些表面活性物质 减少对大驾驶压力的需要并保持稳定的性能 呼吸道衬里液体。灵活的单支路和分支路模型 将被用来研究影响两者的物理化学性质 瞬变压力的大小和与之一致 可以打开支气管树。最后，肺切除实验 将被用来评估表面活性剂的性质对 单倒塌和多次倒塌的压力和稳定性特征 航空公司。所有研究都将在单一-和多个- 组成模型表面活性剂和外源表面活性剂替代品。这个 拟议的工作将解释存在于 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将 最大限度地减少在开孔过程中施加在呼吸道上的机械应力 患有呼吸窘迫综合征的肺部 (RDS)。这项工作还将阐明在 疾病状态下常见的塌陷或阻塞的呼吸道的重新开放 如肺气肿、哮喘和囊性纤维化，因此可能预示着新的 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.