Evaluation of a filter aspiration technique to determine membrane deformability.
A filter aspiration technique for the measurement of red cell membrane deformability described by Brailsford et al. (Blood Cells 1977;3:25) was evaluated. Pore diameters of 0.6 and 1.0 micron were used. Portions of red cells were aspirated with various hydrostatic pressures between 1 and 9 mm H2O. After fixation the filter was removed and the length and radius of the pressure-induced tongues measured by scanning electron microscopy. One to several tongues per cell were observed. The number of tongues had no influence on the measurements at pressures less than or equal to 7 mm H2O. The elastic modulus of the red cell membrane was calculated; it yielded 2.9 (+/- 0.4) X 10(-3) dynes/cm. Data obtained with filter aspiration were compared with the results obtained concurrently with the micropipette technique. A good correlation was found for normal red cells (r = 0.74, P less than 0.001). Stomatocytes produced by chlorpromazine in vitro had an increased elastic modulus with both methods. For echinocytes produced by salicylate or adenosine triphosphate depletion, the elastic modulus as determined by filter aspiration was normal, but the modulus as measured by micropipette aspiration was increased. Possible reasons for the difference are discussed. We conclude that the filter aspiration is a valid technique to measure elastic properties of red cell membranes, except when there are surface irregularities, such as those in the echinocytes.
Reinhart
W H
WH
Department of Physiology, Columbia University College of Physicians and Surgeons, New York, NY.
Chabanel
A
A
Vayo
M
M
Chien
S
S
D004907:Erythrocyte Deformability; D005374:Filtration; D006801:Humans; D008433:Mathematics; D008722:Methods; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning