Sekretanalyse und Clearance.

Mucus is a viscoelastic gel consisting of water and complex high-molecular-weight glycoproteins and proteins, lipids, nucleic acids, and cell components as well. Ideally, for biophysical examinations mucus should be collected free of saliva and other contaminations. The sample should be processed and analyzed immediately. Such a sample collection process is invasive, therefore, for practical reasons sputum is frequently analyzed. Evaluating viscoelastic properties of airway secretions without examining their relation to mucus clearance is of little diagnostic value. The mucus clearance of the airways is influenced by the properties of the serous periciliary fluid lying on the interface between mucus and respiratory epithelium, by the ciliary function, and by the interactions between mucus and airflow or mucus and cilia. But the physical properties of the mucus gel are the major influence. Analysis of the mucus rheology is helpful in characterizing viscosity and elasticity. In this article methods for mucus collection, storage, and examination are presented and discussed. Simple assays to determine macociliary and cough clearance and the correlation between mucus rheology and mucus clearance are demonstrated. Microtechniques facilitating the analysis of very small mucus samples are introduced. The magnetic microrheometer serves as an example. The comparison of the biophysical data of mucus samples clearly demonstrates differences between various respiratory diseases. These differences can be an indication of the basic pathophysiological mechanisms involved. Additionally, the effects of a mucolytic therapy with aerosolized amiloride in cystic fibrosis patients is presented