Biorheology - Volume 27, issue 1

Article Type: Editorial

DOI: 10.3233/BIR-1990-27112

Citation: Biorheology, vol. 27, no. 1, pp. I-III, 1990

Authors: Silberberg, Alex | Copley, Alfred L.

Article Type: Editorial

DOI: 10.3233/BIR-1990-27101

Citation: Biorheology, vol. 27, no. 1, pp. 1-1, 1990

Authors: Copley, Alfred L.

Article Type: Other

Keywords: Biofluid mechanics, biomechanics, biorheology, endoendothelial fibrin(ogenin) lining, fluid mechanics, hemodynamics, hemorheology, history of medicine, history of science, hydrodynamics, Leonardo da Vinci, perihemorheology, rheology, vessel-blood organ

DOI: 10.3233/BIR-1990-27102

Citation: Biorheology, vol. 27, no. 1, pp. 3-19, 1990

Authors: Norton, James M.

Article Type: Research Article

Abstract: To investigate the role of red blood cell (RBC) geometry in determining the filterability of stress-induced macrocytes, measurements of RBC volume, diameter, and passage time through 3 micron and 5 micron filters were made on RBCs from control rats and from phenylhydrazine-treated rats during a 28-day recovery period following the peak hemolytic response to the anemia induced by phenylhydrazine (PHZ). Mean cell volumes (MCV) were calculated from volume distribution curves; RBC diameters were obtained from peripheral blood smears; surface area (SA) and mean cylindrical diameter (MCD) were calculated using a biconcave erythrocyte model. At the time of the peak macroreticulocyte …response to PHZ, MCD and MCV were significantly increased compared to controls (3.07 vs 2.57 microns, and 102.1 vs 59.7 cubic microns, respectively), the ratio SA/MCV was significantly reduced (1.405 vs 1.670), and RBC filterability through both 3 and 5 micron cylindrical pores was significantly reduced. During the 28-day recovery period, MCV, MCD, SA/MCV, and filterability all returned toward the control values, MCD was inversely correlated with filterability through both 3 micron (r = -0.861, p < .01) and 5 micron (r = -0.767, p < .01) pores, and MCD fell below 3.6 microns in 97.5% of the animals despite the persistence of large macrocytic subpopulations. These results emphasize the correlation between RBC geometry and filterability, and demonstrate that macrocytes with favorable geometry can persist in the circulation for extended periods without remodeling or reduction in size. Show more

Keywords: erythrocyte deformability, erythrocyte volume, macrocytosis, reticulocytes, anemia

DOI: 10.3233/BIR-1990-27103

Citation: Biorheology, vol. 27, no. 1, pp. 21-37, 1990

Authors: Boynard, M. | Lelievre, J.C.

Article Type: Research Article

Abstract: Different methods are commonly used to study the red blood cell aggregation phenomenon. The major interest of the ultrasonic method presently discussed is to assess the mean size of red blood cell (RBC) aggregates by measuring ultrasonic intensity backscattered by blood. Applying Rayleigh theory of sound to blood medium, one can show that the scattered ultrasonic intensity is proportional to the 6th power of the size of the RBC aggregates. The ultrasonic method is used to evaluate the mean size of RBC aggregates induced by dextrans. RBCs are suspended at various hematocrits H, in solution of dextrans of different molecular …weights M and at different weight concentrations Cw . Results are presented by using the ultrasonic backscattering coefficient χ which is a relevant quantity in a scattering experiment. For suspensions of RBCs aggregated with dextran of molecular weight 70 000 dalton (dextran 70) at concentration Cw = 40 g/l, variations of χ as a function of H are similar to those obtained for normal blood. At a fixed hematocrit, variation of χ versus Cw for dextran 70 exhibits a maximum at 40 g/l. In the case of RBCs suspended at hematocrit 20 % and aggregated with dextrans of molecular weight M, 70 000 ⩽ M ⩽ 2 000 000, the variations of χ versus molar concentration Cm are similar to those of the microscopic aggregation index defined by Chien (1). Finally, a statistical model of the blood structure previously described (2) is applied to evaluate the mean size of the aggregates. According to this model, the mean size of aggregates is independent of hematocrit for H ⩽ 40 % and independent of the molecular weight of dextran for M ⩾ 150 000 dalton. Show more

Keywords: Ultrasound Backscattering, Red Blood Cell, Aggregation, Dextran

DOI: 10.3233/BIR-1990-27104

Citation: Biorheology, vol. 27, no. 1, pp. 39-46, 1990

Authors: Arai, Koichi | Iino, Masaaki | Shio, Hideo | Uyesakat, Nobuhiro

Article Type: Research Article

Abstract: Although the filtration method has been widely employed in red cell deformability studies, the structural irregularity of the pores of a Nuclepore polycarbonate membrane has always been a major problem. Anegawa, T. et al. (Clin. Hemorheol., 7, 1987) obtained a higher reproducibility with the filtration method using a newly designed thin metal film with pores engraved by the photofabrication technique. We further studied the pressure - flow rate relationship of red cell suspension employing this nickel mesh. The filtration of red cell suspensions through the nickel mesh was not influenced by leukocytes contamination or added leukocytes up to a leukocyte …count of 250 cells/mm3 within an experimental limitation. On the other hand, the flow was greatly influenced by leukocytes contamination when the polycarbonate membrane was used. The nickel mesh was found to be useful in detecting major determinants of red cell deformability, such as cell geometry and internal cellular viscosity, and in detecting abnormalities of red cell deformability in a patient with microangiopathic hemolytic anemia. In conclusion, the present study clearly shows that the nickel mesh is preferable for investigating red cell deformability to the polycarbonate membrane from a quantitative point of view. This material should contribute to the physiologic and clinical investigation of red cell deformability. Show more

Keywords: Red Cell Deformability, Nickel Mesh, Pressure-Flow Rate Relationship, Leukocyte, Microangiopathic Hemolytic Anemia

DOI: 10.3233/BIR-1990-27105

Citation: Biorheology, vol. 27, no. 1, pp. 47-65, 1990

Authors: Kage, H.S. | Engelhardt, H. | Sackmann, E.

Article Type: Research Article

Abstract: Suspensions of erythrocytes in media of low conductivity are subjected to homogenous high frequency electric fields (1 MHz, approximately 10 to 40 kV/m). The resulting transient deformation of the cells is measured by laser light diffraction. Employing a viscoelastic model of the erythrocyte membrane, relative values of membrane shear modulus and response time can currently be determined to within 7% or better. with a measurement time of one minute the average values of some 105 cells can be obtained. As a test of the method, osmotic swelling and deflation of the cells and crosslinking their membrane skeleton by diamide …are used to alter the viscoelastic properties of the erythrocytes. Show more

Keywords: Erythrocyte deformability, biomechanics

DOI: 10.3233/BIR-1990-27106

Citation: Biorheology, vol. 27, no. 1, pp. 67-78, 1990

Article Type: Abstract

DOI: 10.3233/BIR-1990-27107

Citation: Biorheology, vol. 27, no. 1, pp. 79-102, 1990

Article Type: Abstract

DOI: 10.3233/BIR-1990-27108

Citation: Biorheology, vol. 27, no. 1, pp. 103-108, 1990

Article Type: Letter

DOI: 10.3233/BIR-1990-27109

Citation: Biorheology, vol. 27, no. 1, pp. 109-119, 1990