Physical properties of sputum VIII. The effect of lyophilization and reconstitution on the viscosity of sputum 1

Abstract

The effect of lyophilization and reconstitution on the viscosity of sputum was studied under various conditions of freezing and storage. The results indicate that: 1) the procedure produces a material of uniform rheological characteristics and 2) that preservation of the original viscosity depends on the nature of the sample. Thus, in mucoid sputum the viscosity is well preserved when the fresh sample is frozen and stored at −78°C and then lyophilized and reconstituted to the original concentration of solids. In mucopurulent samples the same could be obtained at either −78°C or −198°C, whereas neither of the above temperatures could prevent a decrease of viscosity in frankly purulent sputum samples.