Biorheology - Volume 20, issue 5

Authors: Takaki, R. | Yasuzumi, K.

Article Type: Research Article

Abstract: A flow of a highly concentrated latex suspension around a solid body in a thin layer between two parallel glass plates was observed by an optical microscope. A clear region, where suspended particles were rare, appeared near the rear stagnation point of the body. A model for. explaining this phenomenon is proposed, in which the area of the clear region depends on an average size of aggregates of suspended particles. A possibility is suggested to use this phenomenon for measuring aggregate size in concentrated suspensions.

Keywords: Aggregate, Latex, Suspension, Hele Shaw flow

DOI: 10.3233/BIR-1983-20511

Citation: Biorheology, vol. 20, no. 5, pp. 547-555, 1983

Authors: Takano, Y. | Sakanishi, A.

Article Type: Research Article

Abstract: In order to consider the effect of membrane fluidity upon the mechanical property of biological cell suspensions, we have calculated the complex intrinsic viscosity [ η ∗ ] = [ η ′ ] − i [ η ″ ] of spherical shell structures with material incompressibility in suspension as a function of the dimensionless frequency x = ω η ′ a / γ ′ together with the parameters of h m = η m …/ η ′ , g = γ / γ ′ , h = η / η ′ , δ = d / a , where a is the radius of the cell, d is the width of the membrane, η , η m , and η ′ are the viscosities of the medium, of the membrane and of the internal region of the cell, γ and γ ′ the surface tensions at the outer and the inner side of the membrane respectively, and w the angular frequency. The result is simply represented by two dispersions as follows: [ η ∗ ] / [ η ] = A 1 + B 1 / ( 1 + i ω τ 1 ) + B 2 / ( 1 + i ω τ 2 ) . Here i is the imaginary unit, A 1 = 2 ( 1 − h ) / ( 2 + 3 h ) + O ( δ ) , B 1 = 3 h / ( 5 + 5 h ) + O ( δ ) , B 2 = h ( 19 + 16 h ) / { 5 ( 1 + h ) ( 2 + 3 h ) } + O ( δ ) , τ 1 = { ( 5 / 24 ) ( 1 + h ) ( 1 + 1 / g ) δ − 2 + O ( δ − 1 ) } a η ′ / γ ′ , τ 2 = [ ( 2 + 3 h ) ( 19 + 16 h ) / 40 ( 1 + h ) ( 1 + g ) + O ( δ ) ] a η ′ / γ ′ and [ η ] = ( 5 / 2 ) { 96 h m g + 32 g ( 5 + 5 h − 12 h m ) δ + O ( δ 2 ) } / { 96 h m g + 32 g ( 5 + 2 h − 12 h m ) δ + O ( δ 2 ) } . Show more

Keywords: viscoelasticity, suspension, cell, fluidity, membrane

DOI: 10.3233/BIR-1983-20512

Citation: Biorheology, vol. 20, no. 5, pp. 557-567, 1983

Authors: Imaizumi, Kazuhiko | Shiga, Takeshi

Article Type: Research Article

Abstract: Using a rheoscope, combined with a TV image analyzer and a computer, the effects of immunoglobulins and IgG-fragments on the process of human erythrocyte aggregation were determined. The immunoglobulins accelerated the aggregation; the effect increased with their molecular weight, i.e., IgG ≃ γ -globulin < IgA < IgM. An empirical relationship, expressing the dependence on the immunoglobulin concentrations, was proposed. F(ab′)2 -fragment accelerated the aggregation, more effectively than IgG, while Fab- and Fc-fragments did not. Therefore, two Fab-portions are presumably needed to form the aggregates, and the flexibility between two Fab-portions may be important. A case of multiple myeloma …showed an increased aggregation, due to the increased myeloma protein. Show more

Keywords: Erythrocytes (human), Aggregation, Immunoglobulin, Multiple myeloma, IgG-fragments

DOI: 10.3233/BIR-1983-20513

Citation: Biorheology, vol. 20, no. 5, pp. 569-577, 1983

Authors: Oka, Syoten

Article Type: Research Article

Abstract: An entire settling curve for whole blood is derived theoretically based upon Chien’s expression for the viscosity of whole blood at hematocrits in excess of 40%. This problem was already studied by Puccini et ale in 1977. The aim of this note lies in correcting a mistake found in their treatment of a differential equation. The functional form of the entire settling curve differs, of course, from that obtained by them. It is shown that the settling curve is governed by only two parameters. The comparison of our theoretical formula with experimental data is left for our future task. It …is suggested that the meniscus will be curved in close neighborhood of the glass wall due to the fluid mechanical influence of the wall. The effect of the aggregation of red cells will also be taken into account in future. Show more

Keywords: erythrocyte sedimentation rate, entire settling curve

DOI: 10.3233/BIR-1983-20514

Citation: Biorheology, vol. 20, no. 5, pp. 579-581, 1983

Authors: Kaibara, Makoto

Article Type: Research Article

Abstract: A purpose of the present study is to make an artificial rouleau of bovine red blood cells which is not capable of rouleau formation under physiological condition. Rheological behaviors of bovine blood forming artificial rouleaux were examined. The modification of cell surface by enzyme trypsin induced rouleau formation, whereas the modification of cell surface by neuraminidase did not cause any aggregate formation. The drastic elevation of the fibrinogen content in bovine red blood cells suspension also brought about the formation of rouleau. The value of dynamic rigidity modulus G′ of bovine red blood cells in saline solution containing high concentration …of fibrinogen is somewhat smaller than that of trypsin treated bovine red blood cells in plasma. The value of G′ of trypsin treated bovine red blood cells in plasma first increased to a maximum value and then decreased with the time. It is supposed that the removal of macromolecules from the cell surface facilitates the mutual approach of cells and causes the formation of rouleau which seems to be the same as that of human and horse bloods. Show more

Keywords: bovine blood, artificial rouleau, viscoelasticity, viscosity

DOI: 10.3233/BIR-1983-20515

Citation: Biorheology, vol. 20, no. 5, pp. 583-592, 1983

Authors: Kato, A. | Arakawa, M. | Kondo, T.

Article Type: Research Article

Abstract: Sheep hemolysate-loaded liposomes were prepared by a modified interfacial deposition technique. The mean diameter of the liposomes was estimated to be about 310 nm. Sheep hemolysate-loaded liposomes were called artificial red blood cells (ARBC). The flow properties of the ARBC suspension (pH 7.4) were measured with a concentric cylinder-type rotational viscometer at low shear rates and were compared with those of sheep red blood cell (SRBC) suspension (pH 7.4). It was revealed that the flow type of the ARBC suspension (pH 7.4) was of pseudoplastic as in the case of SRBC suspension (pH 7.4). The relative viscosity of the ARBC …suspension as a function of particle concentration in the medium was linear and fitted fairly well with the Einstein equation. However, the relative viscosity of SRBC suspension was increased more gradually with increasing particle concentration, and was well presented by the Brinkman equation as a function of particle concentration for concentrated suspensions. It was suggested that this would be due to the difference in particle-particle interaction between the two types of suspensions. The flow properties of the mixed suspensions of the ARBC and SRBC in the suspending medium (pH 7.4) with and without dextran were measured. It was revealed that the relative viscosity of the mixed suspension is reduced with increasing mixing ratio of the ARBC in the suspension, suggesting that the flow properties of the mixed suspension of the ARBC and SRBC are dependent on the ARBC rather than dextran. Show more

Keywords: Sheep hemolysate-loaded liposomes, Carboxymethylchitin, Mixed suspension of artificial red blood cells and sheep red blood cells

DOI: 10.3233/BIR-1983-20516

Citation: Biorheology, vol. 20, no. 5, pp. 593-601, 1983

Authors: Niimi, Hideyuki | Sugihara, Masako | Yamakawa, Takashi

Article Type: Research Article

Abstract: The supply of oxygen to tissue from capillaries may be influenced by hemorheological factors. A hemorheological model is developed for elucidating which factors play a major role in the oxygen transport to tissue. For a capillary tissue unit, a modified cylindrical model of Krogh is used. For blood, two fluids model of red blood cells (RBCs) and plasma is used where hemoglobin release effect is included. Non-equilibrium flows as well as equilibrium flows are examined for various parameters (total flow Q or RBC velocity Vr, discharge hematocrit Hd and capillary hematocrit Hc). In equilibrium flow, Hd and Q determine the …oxygen transport. In non-equilibrium flow, Hc also becomes important. Especially, hemoglobin release effect becomes significant in low Hc flow, which affects the area of lethal region in tissue. Show more

Keywords: capillary flow, hematocrit, hemorheology, non-equilibrium flow, oxygen transfer

DOI: 10.3233/BIR-1983-20517

Citation: Biorheology, vol. 20, no. 5, pp. 603-614, 1983

Authors: Yamamoto, Akemi | Niimi, Hideyuki

Article Type: Research Article

Abstract: Effects of high osmotic media on the shape and deformability of RBC were examined for determining increasing factors of blood viscosity. Dog blood and Urographin (a hypertonic contrast medium) were used; the plasma osmolality was changed by urografin suspended in blood. The viscosity was measured for normal RBC and glutaraldehyde-treated RBC suspensions with a cell volume concentration. The RBC deformability was evaluated from the difference in viscosity between the two suspensions. It was shown that normal RBC suspension increased the viscosity with increase in osmolality at high shear rate; hardened RBC suspension decreased the viscosity with increase in osmolality. It …was concluded that the RBC deformability decreased with increasing osmolality. Show more

Keywords: Blood viscosity, High osmotic media, RBC deformability, RBC shape

DOI: 10.3233/BIR-1983-20518

Citation: Biorheology, vol. 20, no. 5, pp. 615-622, 1983

Authors: Yamamoto, A. | Mineshita, T. | Toyosaki, T.

Article Type: Research Article

Abstract: Dependence of the viscosity of milks on the bore-size of capillary viscometer has been studied at 25°C. Viscosity measurements were carried out with a Maron-Belner type low shear capillary viscometer with various capillary radii (0.0190–0.076 cm) within the shear stress range of 0.2–30 dynes/cm2 at the capillary wall. Each milk showed non-Newtonian flow behavior and dependence on the size of the capillary. The viscosity of human fresh milk and cow’s fresh milk decreased with the decreases in the capillary bore-size within the range of shear stress studied, and the viscosity of homogenized milk, although similar phenomena as above were …Observed in higher shear stress, decreased with the decrease in the capillary bore-size at the range of lower shear stress. The difference in characteristics of capillary bore-size dependence on viscosity may be attributed to the difference in the behavior of fat droplets existing near the wall at which thermal motion of fat droplets will be hindered by the existence of capillary wall. The results were represented by the modified Ree-Eyring generalized flow formula for a flow system containing one Newtonian flow unit and one non-Newtonian flow unit which included additional terms dependent on the capillary bore-size. The viscosity equation suitable for analysing the dependence of viscosity on the capillary bore-size at entire ranges of rate of shear, was derived by assuming the wall layer. Composed of double layers (of thickness do and di - do ) in the flowing liquid in capillary tube, and by combining this equation with the modified Ree-Eyring equation, the values of do and di were calculated. Show more

Keywords: Wall effect, Flow of milks, Double layer model

DOI: 10.3233/BIR-1983-20519

Citation: Biorheology, vol. 20, no. 5, pp. 623-634, 1983

Authors: Quemada, D. | Droz, R.

Article Type: Research Article

Abstract: A Maxwell-type equation, which involves both time-dependent viscosity η ( t ) and elastic modulus G ( t ) is proposed as governing the shear stress difference σ ′ = σ − σ y , where σ and σ y are total and yield shear stresses respectively. A (reaction kinetics) equation for a structure variable λ is written which describes the evolution of blood structure (network ⇄ rouleau ⇄ RBC) in stress formation and stress relaxation measurements …and which also depends on the (constant) applied shear rate γ ˙ 1 . The time dependent viscosity is assumed to involve the solution λ ( t , γ ˙ 1 ) of the rate equation in the same manner than its equilibrium value λ e q ( γ ˙ 1 ) enters in a viscosity equation η ( λ e q ) yet proposed by one of the authors. A simple relation G ( λ ) completes the structural description. General solutions σ ( t ) of the Maxwell-type equation are discussed in the case of stress relaxation (after the cessation of steady flow) and stress formation (under constant shear rate). Especially, the latter exhibits the well-known “overshoot” behavior. Moreover, the long time behavior of the former allows the quantification of the yield shear stress. Lastly one example of application to blood measurements is discussed. Show more

Keywords: Model, Blood, Viscoelasticity, Thixotropy, Yield shear stress, Overshoot

DOI: 10.3233/BIR-1983-20520

Citation: Biorheology, vol. 20, no. 5, pp. 635-651, 1983