H. J. Meiselman From the theoretical studies of Dr. Skalak, it is clear that white cells can significantly influence the pressure-time profile of a red cell/white cell suspen sion, and that the presence of even a small amount of relatively rigid white cells can have a profound effect on the filtration pressure during the latter portion of a filtration experiment. Conversely, white cell effects, regardless of their relative rigidity, are shown to have only minimal effects during the very early (i. e. , 0-2 seconds) phases of the filtration process. Dr. Chien's experimental data support these theoretical studies, in that white cells of different mechan ical properties exhibit different pressure-time curves; pressure-time data for mixtures of leucocytes show shapes which can be predicted from the behavior of relatively homogeneous cell populations. The insensitivity of the very early portions of the filtration process to white cells is again reflected in the calculations made by Dr. Hanss. Using the nominal dilutions, white cell concentrations and the total volume of filtered cell suspension, he indicates that usually less than 1 pore out of 100 is liable to blockage by white cells. He thus concludes that, at the 1% accuracy level, initial filtration data should not be affected by mechanical pore blockage by white cells. Experimental studies by Dr. Lowe and Dr. Stuart question the WBC insensitivity of the early portion of the filtration process. Using a constant flow system, Dr.
Table of Contentsand welcome.- and welcome.- Welcome on behalf of the groupe de travail sur la filtration erythrocytaire.- Welcome on behalf of the groupe de travail sur la filtration erythrocytaire.- The place of red cell filterability in the microcirculation.- The place of red cell filterability in the microcirculation.- Effect of white blood cells on red cell filterability and the measurement of red cell deformability.- Effect of white blood cells on red cell filterability.- Filterability of leucocyte suspensions.- Effects of white blood cells in filtration measurements.- Qualitative and quantitative effects of white blood cells in a positive-pressure filtration system.- Effect of contaminating leucocytes on erythrocyte filterability.- Non-white cell clogging.- Summary.- Preparation of blood samples for filtration studies.- Anticoagulant effects on the measurement of erythrocyte filterability.- Effect of time delay from venepuncture on red cell rheology.- Red cell age distribution in blood centrifugated to remove leucocytes.- Erythrocyte volume stability in selected iso-osmotic buffers.- Influence of the suspending medium on red blood cell filtration.- Summary.- Comparison of different filtration techniques Summary.- Comparison of blood filtration systems with other techniques for assessing red cell deformability.- Comparison of red blood cell geometric and viscoelastic properties with various assays of red blood cell deformability: A preliminary analysis.- Flow techniques and other devices for studying the distribution of the mechanical properties of red blood cells.- Comparison of filtration, micropipette aspiration and viscometry in osmotically swollen red blood cells.- Comparison of whole blood filtration with three other methods of assessing red cell rheology in diabetics.- Preliminary report on the use of a new reusable metallic filter membrane.- Comparison of different types of filters with the use of erythrocytes with artificially bridged membranes.- New evidence on possible clinical relevance of blood filtration systems.- Whole blood filtration in diabetes: What is its clinical meaning?.- Clinical relevance of the Siena technique.- Prognostic significance of whole blood filtration test in patients with cerebral infarction.- Summary.- The best feasible protocol for investigating the clinical effect of a haemorheological agent in leg ischaemia.- Classified biobliography prepared.- Commentary.- Concluding remarks.