Abstract
In a recent article (Biophys. J. 16:585, 1976), we reported measurements of the elastic area compressibility modulus or red cell membranes using micropipette aspiration on osmotically preswollen red cells. Subsequently, we have analyzed the effects of osmotic and hydrostatic pressure driving forces across the cell membrane in conjuction with the mass conservation equation; we find that the change in cell volume due to the reversible movement of water out of the cell can produce one-third of the movement of the cell projection in the pipette tip. Since the actual volume changes is too small to measure directly (about 1% of the total cell volume), we have used an indirect experimental method to provide critical evaluation of the analysis of cell volume change versus applied pressure; this is based on the model that the change in cell volume is inversely proportional to the cellular osmotic strength. We have increased the cellular cation concentration with a drug, nystatin, and measured the elastic area compressibility modulus corrected for osmotic volume changes as a function of cellular osmotic strength. We find that the corrected elastic are compressibility modulus is independent of cellular osmotic strength, which supports the model and calculated correction for the osmotic effect. The elastic area compressibility modulus is 450 dyn/cm at 25 degrees C instead of 300 dyn/cm, determined previously.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cass A., Dalmark M. Equilibrium dialysis of ions in nystatin-treated red cells. Nat New Biol. 1973 Jul 11;244(132):47–49. doi: 10.1038/newbio244047a0. [DOI] [PubMed] [Google Scholar]
- Evans E. A., Waugh R., Melnik L. Elastic area compressibility modulus of red cell membrane. Biophys J. 1976 Jun;16(6):585–595. doi: 10.1016/S0006-3495(76)85713-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Evans E., Fung Y. C. Improved measurements of the erythrocyte geometry. Microvasc Res. 1972 Oct;4(4):335–347. doi: 10.1016/0026-2862(72)90069-6. [DOI] [PubMed] [Google Scholar]
- RAND R. P. MECHANICAL PROPERTIES OF THE RED CELL MEMBRANE. II. VISCOELASTIC BREAKDOWN OF THE MEMBRANE. Biophys J. 1964 Jul;4:303–316. doi: 10.1016/s0006-3495(64)86784-9. [DOI] [PMC free article] [PubMed] [Google Scholar]