Lipid segregation from human erythrocyte tethers.

Fluid shear force may deform point-attached erythrocytes to become droplike shaped and anchored by a single long or 2-4 short tethers. By addition of glutaraldehyde to the medium the cells were fixed such as to stabilize this deformation for ensuing SEM, freeze-fracture, fine structural, and ultrahistochemical studies. Freeze-fracture specimens revealed identical numbers and distribution patterns of membrane particles in both the membrane of tethers and of the droplike portions of red cells.

Alteration by procaine of spectrin cross-links, deformability, and fluidity related properties of the erythrocyte membrane.

The study on procainized human erythrocytes revealed a) temperature dependent changes of cellshapes, b) a significant increase of deformability, c) low amounts of cross-linked membrane proteins, d) a mean cell volume identical with the volume of nonprocainized cells, e) severe reduction of induced anisotropy, f) no loss of negatively charged groups of the glycocalyx, g) decrease of electrophoretic velocity, h) a significant rise of adhesiveness to glass, and i) increase of agglutinability with antiserum and lectin. The findings are discussed in their relationships to alterations of the molecular structure of the red cell membrane.