Die Oberflächenaktivität im Langmuir-Trog bei Quantitäts – und Qualitätsänderung von aktivem Material aus Rattenlungen

Abstract

Differences in activity between 2 samples of surface active material from lung alveoli may have the following causes: the samples contain different amounts of surface active substances or the quality of the surface active material differs. In the 1st case the use of appropriate amounts of active material of the 2 samples in the Langmuir trough leads to identical or very similar surface[long dash]surface tension[long dash]diagrams (FOD). Differences in quality of the surface active substances, however, make it impossible to obtain identical diagrams by variation of the quantity of material used. Films of fresh and dried foam of bronchial larvae fluid were tested in the Langmuir trough and the FOD was measured using a Wilhelmy balance. In a certain range a linear relation between the parameters of surface activity [static, minimal, maximal tension, hysteresis and compressibility index K = [gamma] min/([gamma] max[long dash][gamma]min)] and the logarithm of the amount of material was obtained. Between the different parameters of activity characteristic correlations were found. Deviations from these correlations suggested differences in quality of the surface active substances. Such a difference in quality was demonstrated for surface active material obtained from lungs which had been ventilated with cigarette smoke.