Red Cell Rheology

Hemolysis during filtration through micropores studied by Chien et al. [I] showed a dependence on pressure gradient and pore diameter that, at the time of publication, did not permit an easy interpretation of the hemolytic mechanism. Acting on the assumption that thresholds of hemolysis are easier to correlate with physical forces than extents of hemolysis, we performed a series of experi­ ments repeating some of the conditions reported in [I] and then focusing on low L1P in order to define better the thresholds of hemolysis for several pore sizes. Employing a model of a deformed red cell shape at the pore entrance (based on micropipette observations) we related the force field in the fluid to a biaxial tension in the membrane. The threshold for lysis correlated with a membrane tension of 30 dynes/cm. This quantity is in agreement with lysis data from a number of other investigators employing a variety of mechanisms for introduc­ ing membrane tension. The sequence of events represented here is: a. Fluid forces and pressure gradients deform the cell into a new, elongated shape. b. Extent of deformation becomes limited by the resistance of the cell mem­ brane to undergo an increase in area. c. Fluid forces and pressure gradients acting on the deformed cell membrane cause an increase in biaxial tension in the membrane. d. When the strain caused by this tension causes pores to open in the membrane, the threshold for hemolysis has been reached [2].

Table of Contents:
I.- Section I: Methods for Evaluation of Red Cell Deformability.- Intravascular Rheology of Erythrocytes in Man.- Discussion.- The Aspiration of Red Cell Membrane into Small Holes: New Data.- Red Cell Membrane Deformability: an Examination of Two Apparently Disparate Methods of Measurement.- Discussion of Papers by Brailsford et al. and Bull et al..- Basic Principles of the ‘Filterability Test’ (FT) and Analysis of Erythrocyte Flow Behavior.- Discussion.- Principles and Techniques for Assessing Erythrocyte Deformability.- Discussion.- Viscometric Techniques and the Rheology of Blood.- Discussion.- Section II: Biochemical Basis for Red Cell Shape and Deformability.- Possible Roles for Membrane Protein Phosphorylation in the Control of Erythrocyte Shape.- Discussion.- Human Red Cell Protein Kinase in Normal Subjects and Patients with Hereditary Spherocytosis, Sickle Cell Disease, and Autoimmune Hemolytic Anemia.- Discussion.- Role of ATP Depletion on Red Cell Shape and Deformability.- Discussion.- The Effects of ATP Depletion on the Response of Erythrocytes to Shear Stress.- Discussion.- Effect of Protein Modification on Erythrocyte Membrane Mechanical Properties.- Commentary.- Section III: Clinical Applications.- Antibody-Induced Spherocytic Anemia. I. Changes in Red Cell Deformability.- Antibody-Induced Spherocytic Anemia. II. Splenic Passage and Sequestration of Red Cells.- Discussion of Papers.- Red Cell Deformability Changes in Hemolytic Anemias Estimated by Diffractometric Methods (Ektacytometry)..- Preliminary Results.- Discussion.- II.- Section I: Sickle Cell Rheology.- Laser Diffraction Patterns of Sickle Cells in Fluid Shear Fields.- Discussion.- Deformability of Normal and Sickle Erythrocytes in a Pressure-flow Filtration System.- Microvascular Blood Flowof Sickled Erythrocytes: A Dynamic Morphologic Study.- Discussion of Papers.- Oxygen Delivery to Muscle Cells during Capillary Occlusion by Sickled Erythrocytes.- Discussion.- Rheology of Sickle Cells and Erythrocyte Content.- Discussion.- Experimentally-Induced Alterations in the Kinetics of Erythrocyte Sickling.- Discussion.- Section II: General Theories of Red Cell Shape, Structure, and Rheology.- The Red Cell Shape as an Indicator of Membrane Structure: Ponder’s Rule Reexamined.- Discussion.- Erythrocyte Membrane Elasticity, Fragmentation and Lysis.- Discussion.- Tank Tread Motion of Red Cell Membranes in Viscometric Flow: Behavior of Intracellular and Extracellular Markers (with Film).- Discussion.- Theoretical Aspects and Clinical Applications of the Blood Viscosity Equation Containing a Term for the Internal Viscosity of the Red Cell.- Commentary.- Hemolysis Thresholds in Micro-porous Structures.- Discussion.- Effect of Radio Contrast Media on the Red Blood Cell: An in vitro Study on Human Erythrocytes.- Discussion.- Effects of Storage on the Respiratory Function and Flexibility of Red Blood Cells.- Discussion.- Section III: Summing Up.- Rheological Methods.- The Implications of Rheology for Red Cell Membrane Structure.- Clinical Applications.- Red Cell Rheology: Glossary of Terms.