Rheological Properties Of Mucus Research Articles

On the role of sialic acid in the rheological properties of mucus.

The importance of sialic acid in the rheological properties of mucus has been investigated. Both bovine cervical mucus, which is a gel, and the structural glycoprotein derived from it were studied before and after treatment with neuraminidase which selectively cleaves terminal sialic acid residues. The storage modulus, viscosity and circular dichroism spectrum were all essentially changed after removal of the sialic acid. These results would indicate that removal of sialic acid does not affect the physical structure of the glycoprotein and it is concluded that sialic acid has no significant role in the rheological properties of cervical mucus.

Mammalian respiratory mucociliary clearance.

An in vivo model was designed to provide information on the major factors affecting mammalian mucociliary clearance. It involves simultaneous quantitation of mucous load, tracheal transport velocity, ciliary beat frequency, and rheological properties of mucus. Values in 23 cats were obtained. The results were remarkably consistent for the group as well as for individual cats that were reexamined. The mucous blanket depth measures usually < 10μ, ciliary beat frequency averages 876±151 beats per minute, and transport rate 10.5±3.7 mm/min. Average mucous viscosity was 248±106 poises at a shear rate of 1 sec-1 and recoverable shear strain (elasticity) 3.1±1.1 units at 100 dynes/sq cm. It is suggested that this model can serve as a sensitive indicator of early deleterious effects of airway pollution or noxious inhalants and pinpoint the initial target area.

Rheological properties of mucus

(1) The magnetic rheometer has been shown capable of measuring the viscoelastic properties of very small volumes of mucus, of demonstrating heterogeneity and of reducing these results to a form where it can be discussed in standard rheological terms. (2) The mucus tested appears to have a principal relaxation time in the order of 100 sec which would make it appear as a rubbery solid to the action of cilia. (3) The relaxation spectra of mucus infer the presence of intermolecular entanglement couplings with mucous secretions with distance between entanglement points being approximately twice as great for the specimen cervical mucus as for the specimen of bronchial lung mucus.