Biorheology - Volume 14, issue 1

Authors: Stasiw, D.M. | Puccini, C. | Cerny, L.C. | Ziegler, F. | Grimley, P.

Article Type: Research Article

Abstract: The results of a screening program for heterozygous thalassemia involving 1039 subjects are reported. Identification of possible thalassemia carriers was made on the basis of standard blood indices and quantitative hemoglobin A2 measurements. Various mathematical relationships reported as discriminant functions for possible thalassemia carriers were tested using these data. None of the currently proposed methods suitable for use in a mass screening program performed successfully. Besides the normal hematological parameters, hemorheological variables including shear viscometry, erythrocyte sedimentation rate and osmotic fragility were also studied.

DOI: 10.3233/BIR-1977-14101

Citation: Biorheology, vol. 14, no. 1, pp. 1-10, 1977

Authors: Oosawa, Fumio

Article Type: Research Article

Abstract: Experimental data on the elastic modulus for bending of F-actin are summarized and the microscopic elastic constant of the actin-actin bond is estimated. The elastic modulus for bending is ca . 2 × 10−17 dyne cm2 and the microscopic elastic constant is ca . 2 × 104 dyne cm 1 in the physiological salt condition at room temperature. A profile of the interaction free energy is given as a function of the distance between actin monomers, and the thermodynamic property of the bond is discussed. Then, data are presented to show the conformational change of F -actin …in the thin filament induced by Ca ion and by interaction with myosin or heavy meromyosin. Finally, the possibility that the conformations change of F -actin is involved in muscle contraction or cellular movement and its regulation is suggested. Show more

DOI: 10.3233/BIR-1977-14102

Citation: Biorheology, vol. 14, no. 1, pp. 11-19, 1977

Authors: Pittz, E.P. | Jones, R. | Golberg, L. | Coulston, F.

Article Type: Research Article

Abstract: The effect of dextran, diethylaminoethyl (DEAE) dextran, iota carrageenan, (CG) and combinations of these polymers on the aggregation of human erythrocytes has been studied. Higher molecular weight fractions of CG are much more effective than low molecular weight fractions in enhancing erythrocyte aggregation as observed by sedimentation and photo microscopy. The low molecular weight fraction Mn 9,700 of CG is not competitive with the high molecular weight fraction in effecting sedimentation. Dextran of Mw 170,000 does not appreciably increase the sedimentation of erythrocytes compared to controls up to a concentration of 5 mg/ml. However, dextran enhances the sedimentation …of erythrocytes brought about by 145,000 molecular weight CG. Size distribution curves and photomicroscopy for erythrocytes incubated with CG indicate that the enhanced sedimentation of erythrocytes by CG is not due to a change in density of the erythrocytes. Low concentrations of DEAE dextran (⩾ 0.46 mg/ml) greatly enhance the sedimentation of erythrocytes by CG while higher concentrations of DEAE dextran (⩽ 2.3 mg/ml) cause erythrocytes to sediment at the same rate as controls. Sedimentation of erythrocytes incubated with 1.8 mg/ml CG, Mn 145,000, as a function of DEAE dextran concentration shows an initial increase in sedimentation rate of erythrocytes at 0.46 mg/ml DEAE dextran and then a decrease to control levels at 2.3 mg/ml. These results are interpreted in terms of the ability of the polymers to interact simultaneously with each other and with the erythrocyte surface. Show more

DOI: 10.3233/BIR-1977-14103

Citation: Biorheology, vol. 14, no. 1, pp. 21-31, 1977

Authors: Pittz, E.P. | Jones, R. | Golberg, L. | Coulston, F.

Article Type: Research Article

Abstract: Studies on the aggregation of erythrocytes by iota carrageenans (CG) have been carried out. These studies employ the techniques of measurement of erythrocyte sedimentation rate and photomicroscopy of erythrocytes suspensions as indicators of aggregation. Erythrocyte aggregation by CG decreases as a function of increasing ionic strength. Erythrocyte aggregation by CG is enhanced as the temperature is increased from 5 to 37°C. Trypsin digestion of the erythrocyte surface increases erythrocyte sedimentation by CG. A model is proposed to explain the aggregation of erythrocytes by CG. The model involves complex factors including electrostatic interactions between the erythrocyte surface and CG. The exact …nature of these interactions is hypothesized. Show more

DOI: 10.3233/BIR-1977-14104

Citation: Biorheology, vol. 14, no. 1, pp. 33-42, 1977

Authors: Puccini, C. | Stasiw, D.M. | Cerny, L.C.

Article Type: Research Article

Abstract: A semi-empirical approach is presented to explain the entire settling curve for whole blood. This method uses the Stokes equation as modified by Ponder and Robinson. The major change includes a compact expression for the viscosity of whole blood at hematocrits in excess of 40% based upon the data of Chien. In its final form, the expression gives the height of the plasma level as a function of the time. The shape of the curve is sigmoidal and can be expressed in terms of two parameters.

DOI: 10.3233/BIR-1977-14105

Citation: Biorheology, vol. 14, no. 1, pp. 43-49, 1977

Authors: Vincent, N.M. | Oliver, D.R.

Article Type: Research Article

Abstract: The sedimentation of dextranated human erythrocytes is found to be more reproducible in the presence of controlled shear than in conventional Westergren tubes. The induction period is also greatly reduced in length. It is suggested that the method could be used for measuring clinical ESR’s with greater precision and speed than is possible using current methods.

DOI: 10.3233/BIR-1977-14106

Citation: Biorheology, vol. 14, no. 1, pp. 51-58, 1977

Authors: Scott-Blair, George W.

Article Type: Obituary

DOI: 10.3233/BIR-1977-14107

Citation: Biorheology, vol. 14, no. 1, pp. 59-59, 1977

Article Type: Announcement

DOI: 10.3233/BIR-1977-14108

Citation: Biorheology, vol. 14, no. 1, pp. 61-61, 1977