Red blood cells, phase contrast, interference contrast microscopy and microspectrophotometry

Following Teorell's (1) observation that the ghosts of hypotonically hemolysed erythrocytes reseal, it was shown that during the time they are permeable to hemoglobin, foreign macromolecules (dextran) can enter and that the hemolysed cell can achieve a final colloid-osmotic equilibrial state containing dextran and some residual Hb. In this way dextran reduces the hemoglobin loss in hypotonic hemolysis. Some hemoglobin loss is, however, inevitable, as it begins with a non-diffusive bulk outflow, sometimes observable as a jet, during which time a diffusive influx of the colloid-osmotic "balancer", dextran, is not possible. Finally, as expected from a process which is for the most part diffusive, transmembrane macromolecular transport is bidirectional; during hemolysis smaller molecules escape to a greater extent than larger ones.