A rapid microbiological procedure using Bacillus stearothermophilus for the assay of antibacterial drugs.

objective is to explore cell deformability as a physical characteristic in its own right, techniques using cells resuspended in artificial media (Gregersen et al, 1967; Weed et al, 1969; Forman et al, 1973; SchmidSchdnbein et al, 1973) or packed cell preparations (Jacobs, 1963; Dintenfass, 1965) can yield valuable information. However, as the physical properties of the red cells are almost certainly influenced by the surrounding plasma, we feel that the measurement of RBC deformability in whole blood is more clinically relevant. This appears to be borne out by preliminary studies ofRBC deformability in patients with peripheral circulatory insufficiency (Reid et al, 1976). In trying to reproduce conditions which prevail in the microcirculation the characteristics of the filter used are obviously critical. Several comparative studies of filtering devices have been published (Nicolau et al, 1961; Gregersen et al, 1967; Forman et al, 1973; Rosenmund et al, 1975) and there seems to be general agreement that Nuclepore filters give results which are both sensitive and reproducible.