title: Entry of [3H]water and [1,2-14C]polyethylene glycol 4000 into normal and cystic fibrosis salivary mucus.
abstract: This investigation was performed to compare the entry of [3H]water and [14C]PEG into samples of salivary mucus from patients with CF and normal subjects. A solution containing both radioisotopes was added to samples of salivary mucus and mixed, and entry of each into mucus was determined by their dilution in the supernatant at 1, 2, 4, and 24 hr. [3H]water rapidly entered and equilibrated with the water content of both normal and CF mucus. [14C]PEG entered mucus more slowly than [3H]water and by 24 hr had entered at a ratio of only 0.794 +/- 0.108 and 0.766 +/- 0.039 of the water space accessible to [3H]water in normal and CF mucus, respectively. The mechanisms responsible for the partial exclusion of the large polyethylene glycol molecule were not explored but may reflect steric restriction of access to a portion of mucus water. Thus water entry and solute exclusion, both determinants of permeability, were unaltered in CF mucus, which fact provides evidence against the presence of a generalized defect of mucus permeability in this disease. The techniques developed for this study may be adaptable to the study of the permeability properties of mucus from other sources and other gels.
mesh_terms: D000293:Adolescent; D000328:Adult; D002250:Carbon Radioisotopes; D002648:Child; D003550:Cystic Fibrosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D009093:Mucus; D010539:Permeability; D011092:Polyethylene Glycols; D012463:Saliva / Q000032:analysis*; D014316:Tritium; D014867:Water
chemical_list: D002250:Carbon Radioisotopes; D014867:Water; D014316:Tritium; D011092:Polyethylene Glycols