Biorheology - Volume 25, issue 1-2

Authors: Fukushima, Takayoshi | Homma, Tatsuji

Article Type: Research Article

Abstract: In order to describe a possible effect of smooth muscle cell (SMC) activation on arterial wall distensibility, the present study derived a mathematical equation applicable to relaxed and contracted arterial walls. Pressure(P)-diameter(D) relationship of dog renal arteries was investigated in vitro under a cyclic loading and unloading process in the pressure range of 5–180 mmHg. Smooth muscle cells were activated by 10−5 M norepinephrine. On the basis of the P-D curves obtained with fully contracted arteries, the vessel wall compliance dD/dP was assumed to be given by a second order polynomial of D, dD dP …= − ( D − D max ) ( D − D min ) E ( D max − D min ) The equation, including three parameters, Dmin , Dmax , and E, is integrated to yield the solution similar to the logistic curve as follows D = D min + D max − D min 1 − M ( 0 ) exp ( − P / E ) where D ( 0 ) = ( D max − D ( 0 ) ) / ( D ( 0 ) − D min ) , and D(0) is the diameter at the point P=0 The constant, E, has the same dimension as the modulus of elasticity. The calculated P-D relationships coincided well with the experimental data for contracted and relaxed arteries. The most significant change due to wall contraction took place in the magnitude of M. This result, therefore, suggests that the parameter M is a good index of the degree of SMC contraction. Show more

Keywords: pressure-diameter equation, logistic curve, dog renal artery smooth muscle cell, Hill’s muscle model, compliance

DOI: 10.3233/BIR-1988-251-210

Citation: Biorheology, vol. 25, no. 1-2, pp. 37-48, 1988

Authors: Kon, Kazunori | Murakami, Junko | Takaoka, Kunihiro | Shiga, Takeshi

Article Type: Research Article

Abstract: The red cell deformation under oscillatory shear stress was studied. Shear stress was sinusoidally modulated between 8 and 32 dyn/cm2 , thus, the extent of cellular deformation altered sinusoidally. At a low modulation frequency (less than 1.8 Hz), intact red cells perfectly responded to the shear stress applied on cells, and they could deform as much as the deformation in stationary shear flow. Above 2 Hz, the cellular deformation could not follow changes in shear stress along up-phase in the shear stress cycle. As decreasing the intracelluar hemoglobin concentration, the cellular response to oscillatory shear stress became better. Treatment …of cells with low concentrations of diamide impaired the response of intact cells to oscillatory shear stress, but unaffected the response of partially hemolyzed cells. These data suggest that the cellular response to oscillatory shear stress is determined by the cytoskeletal structure and the intracellular viscosity. Show more

Keywords: Deformability, Erythrocytes, Pulsative Flow, Cytoskeleton

DOI: 10.3233/BIR-1988-251-211

Citation: Biorheology, vol. 25, no. 1-2, pp. 49-56, 1988

Authors: Tomita, Minoru | Gotoh, Fumio | Tanahashi, Norio

Article Type: Research Article

Abstract: The whole blood RBC aggregometer head reported previously for measuring the degree of RBC aggregation in whole blood was tested for its usefulness as a flowmeter of blood vessels in situ . Modifications to its construction were made so that ir-became readily attachable and detachable without damage to the vessels. In ex vivo experiments employing a transparent vinyl tube and freshly drawn heparinized human whole blood, the RBC aggregometer head was applicable for evaluating semiquantitative flow changes within a limited flow range based on the degree of RBC aggregation. A linear relationship was observed between the logarithm of blood …flow in a low shear range (below approximately 180/s) and changes in the light transmission of the flowing blood. The RBC aggregometer head with or without an electromagnetic flowmeter (EMF) was applied to the jugular vein and femoral vein in cats. A stop-flow change of whole blood in the jugular vein was detected by the RBC aggregometer head as a dramatic change in light transmission (LT). The aggregometer head recorded a similar LT change consistently, whereas the EMF was found to be rather discrepant, indicating the occurrence of anomalous flow. It is concluded that the RBC aggregometer head can be used as an semiquantitative flowmeter for relative changes in blood flow in veins in situ . Show more

Keywords: Blood flow velocity, Red blood cell aggregation, Veins, Flow monitoring, Flowmeter, Rheology

DOI: 10.3233/BIR-1988-251-212

Citation: Biorheology, vol. 25, no. 1-2, pp. 57-64, 1988

Authors: Dintenfass, L.

Article Type: Research Article

Abstract: Experiment on STS 51-C in January 1985, carried out on blood samples obtained from patients with heart disease, diabetes, hyperlipidaemia and cancer showed that, under zero gravity, the morphology of red cell aggregates aggregates was normal, in contradistinction to the parallel and simultaneous observations under 1 g, which showed large and unorientated clumps of red cells. As such clumps could be considered of disadvantage in the microcirculation and tissue perfusion, the zero gravity observations were significant in a number of ways. In particular, a preliminary deduction (subject to further zero g experimentation) was that cell-cell interaction and adhesion are affected …by zero gravity, and that most likely the microarchitecture of the cell membrane is modified; and that probably the receptors, their position and/or activity, are affected by zero gravity. Of particular interest could be a possible change in the properties of the discrete surface areas which respond preferentially to specific macromolecules (or ligands). There is a dissonance between these in vitro results and theoretical deductions on flow in the microcirculations by Oka, and as well of deductions on space sickness by Dintenfass, both assuming a disabling effect of zero g on the in vivo microcirculation. This dissonance should be explored, as effect of zero g might be different on blood flow in vivo and in vitro. However, the data available from the in vitro experiment suggest that studies in immunology and oncology might be enriched by zero gravity findings; and that studies under zero gravity might open a new avenue of research In these important fields. Show more

Keywords: aggregation of red cells, morphology of aggregates, effect of zero gravity on cell-cell interaction, platelets, immunoglobulins, membrane receptors

DOI: 10.3233/BIR-1988-251-213

Citation: Biorheology, vol. 25, no. 1-2, pp. 65-76, 1988

Authors: Wu, Y.P. | Wang, G.R. | Sha, J.P. | Wang, L.G. | Qu, N.X. | Lu, C.Y. | Yu, Y.M.

Article Type: Research Article

Abstract: We have used hydroelastic waves to treat the closed trauma of the soft tissue. The Shu Huo Jiu (S.H.J.) which is the Chinese traditional medicine alcohol, was used as the fluid medium for generating the pressure waves. The biomechanical model was established and analysed. Both animal and human tests have been made. A practical system was designed, constructed and clinically tested to treat the closed trauma, such as the bruise, contusion, sprain etc.. This system was found to be effective.

DOI: 10.3233/BIR-1988-251-214

Citation: Biorheology, vol. 25, no. 1-2, pp. 77-83, 1988

Authors: Cerny, L.C. | Cerny, E.L. | Granley, C.R. | Compolo, F. | Vogels, M.

Article Type: Research Article

Abstract: In order to obtain a better understanding of the erythrocyte sedimentation rate (ESR), several models are presented. The first directs attention to the importance of geometrical models to represent the structure of mixtures. Here it is our intention to understand the effect of the structure on the packing of red blood cells. In this part of the study, “Cheerios” (trademark General Mills) are used as a macroscopic model. It is interesting that a random sampling of “Cheerios” has the same volume distribution curve that is found for erythrocytes with a Coulter Sizing Apparatus. In order to examine the effect of …rouleaux formation, the “Cheerios” are stacked one on top of another and then glued. Rouleaux of 2, 3, 4, 5, 7 and 10 discs were used. In order to examine a more realistic biological model, the experiments of Dintenfass were used. These investigations were performed in a split-capillary photo viscometer using whole blood from patients with a variety of diseases. The novel part of this research is the fact that the work was performed at 1g and at near zero gravity in the space shuttle “Discovery.” The size of the aggregates and/or rouleaux clearly showed a dependence upon the gravity of the experiment. The purpose of this model was to examine the condition of self-similarity and fractal behavior. Calculations are reported which clearly indicate that there is general agreement in the magnitude of the fractal dimension from the “Cheerios” model, the “Discovery” experiment with those determined with the automatic sedimentimeter. The final aspect of this work examines the surface texture of the sedimention tube. A series of tubes were designed with “roughened” interiors. A comparison of the sedimentation rates clearly indicates a more rapid settling in “roughened” tubes than in ones with a smooth interior surface. Show more

Keywords: Cheerio model, rouleaux, zero gravity, roughened tubes

DOI: 10.3233/BIR-1988-251-215

Citation: Biorheology, vol. 25, no. 1-2, pp. 85-94, 1988

Authors: Flaud, P. | Quemada, D.

Article Type: Research Article

Abstract: A non-linear elastic model taking into account the microscopic structure of biological soft tissues is briefly presented and extended to quasi linear viscoelasticity. The modelling of the rheological behavior for near zero stress values is then discussed.

Keywords: structural model, non linearities, viscoelasticity

DOI: 10.3233/BIR-1988-251-216

Citation: Biorheology, vol. 25, no. 1-2, pp. 95-105, 1988

Authors: Sugiura, Y.

Article Type: Research Article

Abstract: Viscosity measurements were made using a coaxial rotating cylinder viscometer for blood having various volume fractions of red cells. A method is described for analyzing non Newtonian blood viscosity in low shear rates by taking account of an increase or a decrease in size of red cell aggregates induced by shear. Our results are compared with empirical formulae presented by Scott Blair. Weaver Evans Walder and Thurston.

Keywords: Blood viscosity, Non Newtonian viscosity, Low shear rate, Rouleau formation

DOI: 10.3233/BIR-1988-251-217

Citation: Biorheology, vol. 25, no. 1-2, pp. 107-112, 1988

Authors: Murata, T. | Secomb, T.W.

Article Type: Research Article

Abstract: A kinetic equation for rouleau formation in a simple shear flow is derived, based on several assumptions. These are (a) colliding rouleaux stick to one another with a certain probability to form a single rouleau; (b) simultaneous collisions between more than two rouleaux are negligible; (c) rouleaux are broken by a viscous force exerted by the suspending fluid on the surfaces of rouleaux; (d) when a rouleau is broken by viscous forces, only two fragments are formed. Based on a simple mathematical model, collision rate, sticking probability and degradation rate are obtained as functions of applied shear rate. From the …solution of the kinetic equation, the average size of rouleaux is obtained as a function of time with shear rate as a parameter. It is shown that the average size of rouleaux increases monotonically with increasing time and tends to an equilibrium size. The average size of rouleaux in a dynamical equilibrium decreases monotonically with increasing shear rate and tends to one cell as shear rate approaches infinity. It is also found that the initial rate of rouleau formation increases with increasing shear rate at very low shear rate, but this trend is reversed at higher shear rates. The theoretical results are compared quantitatively with experimental data. Show more

Keywords: aggregation, rouleau, collision rate, degradation rate, sticking probability

DOI: 10.3233/BIR-1988-251-218

Citation: Biorheology, vol. 25, no. 1-2, pp. 113-122, 1988

Authors: Takano, Yo | Sakanishi, Akio

Article Type: Research Article

Abstract: To consider the effects of the viscoelasticity of cytoplasm on the relaxation phenomenon of red blood cell suspensions, we calculate the complex intrinsic viscosity [ η ∗ ] = lim c → 0 ( η ∗ − η ) / η c of the disperse system of spherical cells as a function of the frequency, where η ∗ is the complex viscosity in suspensions, η the medium viscosity and c the volume concentration of the cells. The cell …consists of a viscoelastic membrane and a viscoelastic cytoplasm. The viscoelasticity of the membrane is described by the Voigt model, while the viscoelasticity of the cytoplasmic region is described either by the Maxwell model or by the Voigt model. The interfacial tension is taken into account on both the interfaces of the membrane. The results of [ η ∗ ] are compared with the ones in the case in which the cytoplasmic region is purely viscous liquid. Show more

Keywords: viscoelasticity, suspension, red blood cell, viscoelastic membrane, viscoelastic cytoplasm, relaxation

DOI: 10.3233/BIR-1988-251-219

Citation: Biorheology, vol. 25, no. 1-2, pp. 123-128, 1988