Hills B A
J Physiol. 1985 Feb;359:65-79. doi: 10.1113/jphysiol.1985.sp015575.
The Langmuir trough has been used to study monolayers of surfactant from beef lung extracts, dog lavage and the principal component (dipalmitoyl lecithin; DPL) in which surface tension has been simultaneously monitored on each film by the Wilhelmy method and the original Langmuir method whose readings are independent of contact angle. Readings on the Wilhelmy balance at 80% film compression reached the near-zero values recorded in previous studies, averaging 2.0 dyn cm-1, but Langmuir readings on the same films averaged 13.5 dyn cm-1 for DPL with no reading below 7.0 dyn cm-1. Similar differences were found for bovine extracts and dog lung lavage and have been attributed to a serious contact-angle artifact in the Wilhelmy method widely used in studying pulmonary surfactant. Higher minimum values of surface tension determined by the Langmuir method are shown to be incompatible with normal physiological function in the smaller mammals on the basis of the traditional bubble model of the alveolus. When Langmuir or Wilhelmy values are determined under more physiological conditions of area change, pH, temperature, humidity etc., values for surface tension are even higher and less compatible with the concept of a continuous liquid lining for the alveolar diameter of any mammal.
朗缪尔槽已被用于研究来自牛肺提取物、犬灌洗物中的表面活性剂单分子层以及主要成分（二棕榈酰卵磷脂；DPL），其中通过威廉米方法和原始朗缪尔方法同时监测每一层膜的表面张力，这两种方法的读数均与接触角无关。在薄膜压缩至80%时，威廉米天平的读数达到了先前研究中记录的接近零的值，平均为2.0达因/厘米，但相同薄膜上DPL的朗缪尔读数平均为13.5达因/厘米，且没有低于7.0达因/厘米的读数。在牛提取物和犬肺灌洗物中也发现了类似差异，这归因于广泛用于研究肺表面活性剂的威廉米方法中存在严重的接触角假象。基于传统的肺泡气泡模型，朗缪尔方法测定的更高表面张力最小值与较小哺乳动物的正常生理功能不相符。当在更接近生理条件的面积变化、pH值、温度、湿度等条件下测定朗缪尔值或威廉米值时，表面张力值甚至更高，并且与任何哺乳动物肺泡直径的连续液体衬里概念更不相符。
