The influence of oxygen tension, temperature, and hemoglobin concentration
on the rheologic properties of sickle erythrocytes
LH Mackie and RM Hochmuth
Department of Biomedical Engineering, Duke University, Durham, NC.
With the use of micromanipulation techniques, the shear modulus or
"rigidity" mu, the recovery time tc, and the unfolding time tf for
individual sickle cells have been measured at different oxygen tensions,
temperatures, and cell densities. In these experiments, the partial
pressure of oxygen was varied from 156 to 40 mm Hg and the temperature was
controlled at 25 degrees C or 37 degrees C. Three mean cellular hemoglobin
concentrations were studied: 29 g/dL, 33 g/dL, and 46 g/dL. The lighter
cells (29 and 33 g/dL) exhibited at most a threefold increase in rigidity
as the pO2 was decreased from 156 to 40 mm Hg. At 25 degrees C, the densest
cells (46 g/dL) also exhibited a threefold increase. However, at 37 degrees
C, the rigidity of these cells increased eightfold between 156 to 40 mm Hg.
Compared with normal cells, this gives a rigidity that is 18 times larger.
In contrast to the values for mu, the values for tc and tf remained
essentially unchanged (within the accuracy of the experiments) for the
lighter cells and could not be measured for the densest cells.
Volume 76,
Issue 6,
pp. 1256-1261,
09/15/1990
Copyright © 1990 by The American Society of Hematology
