Measuring RBC-deformability by microdiffractometrv in the rheoscope

Abstract

By introducing a ‘Bertrand-lens’ into the optical system of a rheoscope, we succeeded in simultaneously observing the red blood cells (RBC) and their diffraction pattern under uniform shear stress in a counter-rotating cone-plate chamber. The photographed image of the diffraction pattern is scanned by microdensitometry. Thus, it becomes possible to correlate the diffractional signal to the apparent elongation (E') measured from the microphotographs of the cells. The apparent elongation measured by diffractometry is systematically lower than that of the projected image of the RBC—but strongly correlated (r = 0.955). The method allows measurements of RBC in Dextran solutions, as well as in their native plasma with hematocrits up to 60%.

Key Words:

• Rheoscope
• ektacytometry
• diamide-treated cells