Blood Filtration and Blood Cell Deformability : Summary of the Proceedings of the Third Workshop Held in London, 6 and 7 October 1983, Under the Auspices of the Royal Society of the Medicine and the Groupe De Travail Sur La Filtration Erythrocitaire

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. Front Matter....Pages I-X Introduction and welcome....Pages 1-1 Welcome on behalf of the Groupe de Travail sur la Filtration Erythrocytaire....Pages 3-3 The place of red cell filterability in the microcirculation....Pages 5-9 Front Matter....Pages 11-11 Effect of white blood cells on red cell filterability....Pages 13-14 Filterability of leucocyte suspensions....Pages 15-16 Effects of white blood cells in filtration measurements....Pages 17-17 Qualitative and quantitative effects of white blood cells in a positive-pressure filtration system....Pages 18-19 Effect of contaminating leucocytes on erythrocyte filterability....Pages 20-22 Non-white cell clogging....Pages 23-24 Summary....Pages 25-26 Front Matter....Pages 27-27 Anticoagulant effects on the measurement of erythrocyte filterability....Pages 29-33 Effect of time delay from venepuncture on red cell rheology....Pages 34-35 Red cell age distribution in blood centrifuged to remove leucocytes....Pages 36-36 Erythrocyte volume stability in selected iso-osmotic buffers....Pages 37-40 Influence of the suspending medium on red blood cell filtration....Pages 41-42 Summary....Pages 43-44 Comparison of different filtration techniques....Pages 45-51 Front Matter....Pages 53-53 Comparison of red blood cell geometric and viscoelastic properties with various assays of red blood cell deformability: A preliminary analysis....Pages 55-57 Flow techniques and other devices for studying the distribution of the mechanical properties of red blood cells....Pages 58-60 Comparison of filtration, micropipette aspiration and viscometry in osmotically swollen red blood cells....Pages 61-62 Front Matter....Pages 53-53 Comparison of whole blood filtration with three other methods of assessing red cell rheology in diabetics....Pages 63-64 Preliminary report on the use of a new reusable metallic filter membrane....Pages 65-65 Comparison of different types of filters with the use of erythrocytes with artificially bridged membranes....Pages 66-67 Front Matter....Pages 69-69 Whole blood filtration in diabetes: What is its clinical meaning?....Pages 71-72 Clinical relevance of the Siena technique....Pages 73-74 Prognostic significance of whole blood filtration test in patients with cerebral infarction....Pages 75-75 Summary....Pages 76-77 The best feasible protocol for investigating the clinical effect of a haemorheological agent in leg ischaemia....Pages 78-84 Classified bibliography....Pages 85-98 Commentary....Pages 99-100 Concluding remarks....Pages 101-102 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 suspenƯ 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 mechanƯ 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 WBCƯ insensitivity of the early portion of the filtration process. Using a constant flow system, Dr Summary of the Proceedings of the Third Workshop held in London, 6 and 7 October 1983, under the auspices of the Royal Society of Medicine and the Groupe Travail sur la Filtration Erythrocytaire