Biorheology - Volume 19, issue 5

Authors: Lerche, D.

Article Type: Research Article

Abstract: Aggregation measurements of washed human erythrocytes (RBC) were made in an NaCl-PBS solution under laminar shear conditions. An artificial aggregation was caused by decreased pH and reduced ionic strength and characterized by collision efficiency, i.e. the probability of permanent aggregate formation. It was found that aggregation increases with reduced ionic strength and decreased pH value of the medium. Aggregation can be inhibited by addition of human serum albumin and neuraminidase treatment (removal of sialic acids). As calculations show, the results cannot be explained by the force balance between electrostatic repulsion and attraction due to dispersion forces. It was assumed that …this type of aggregation involves reversible changes of the surface structure of REC. Possible conclusions for the arrangement of the glycophorins of the glycocalyx (surface coat) are discussed. Show more

Keywords: aggregation, RBC, surface structure, ionic strength

DOI: 10.3233/BIR-1982-19501

Citation: Biorheology, vol. 19, no. 5, pp. 587-598, 1982

Authors: Takano, Y. | Sakanishi, A.

Article Type: Research Article

Abstract: The rigidity of a dilutely dispersed system of spherical particles having an elastically anisotropic shell is theoretically obtained in the case of material incompressibility. Considering characteristics of biological cells the complex intrinsic viscosity [η ∗ ] of this system is numerically calculated in the case that the medium and the inside region of the shell contain viscous liquids and the shell region is made of an elastic substance. In [η ∗ ] vs. frequency curves anomalies occur at some range of anisotropic parameters. This anomaly may be called a negative …relaxation, when the relaxation strength takes a negative value. Show more

Keywords: viscoelasticity, dispersion, cell, anisotropy, membrane

DOI: 10.3233/BIR-1982-19502

Citation: Biorheology, vol. 19, no. 5, pp. 599-611, 1982

Authors: Mchedlishvili, George | Varazashvili, Manana

Article Type: Research Article

Abstract: The flow conditions of red cells and plasma in microvascular ramifications were investigated in a biological model of the frog’s retrolingual membrane. Upon the controllable reduction of blood flow from the arterioles into the microvascular bed, with an appropriate decrease of red cell: plasma ratio in the blood, a tendency of the red cells to be drawn along the parent main capillaries without entering the branching capillaries was in evidence. These latter thus transformed into the plasmatic capillaries deprived of red cells. The factors being responsible for this process were found to be as follows: (a) the diameter of branching …capillaries, (b) the angles of off-shoots, (c) the degree. of slow-down of blood flow velocity in the branches, and (d) the reduction of red cell: plasma ratio in parent vessels. The direct relationship was found between these factors and the transformations of the off-shoots into the plasmatic capillaries. Show more

Keywords: blood flow conditions in bifurcations, red cell: plasma ratio in microcirculation, red cell and plasma separation in microvessels, active and plasmatic capillaries, microcirculation

DOI: 10.3233/BIR-1982-19503

Citation: Biorheology, vol. 19, no. 5, pp. 613-620, 1982

Authors: Eichhorn, Jean-Louis

Article Type: Research Article

Abstract: In order to take measurements of electrical and mechanical characteristics on red blood cells in motion in a hydrodynamic or electric field, a micro laser doppler anemometry apparatus was developed. Because of the small dimensions of the scattering volume of this apparatus, measurements can be taken on individual cells. Two fields of measurement were studied: that of red blood cells in free motion in a hydrodynamic field (speeds of a few mm/s), an that of very low speeds (a few μ m/s) the cells moving in a hydrodynamic or an electric field. We can thus obtain simultaneously for each red …blood cell: the apparent dimension, the speed, the electrical charge. This methodology gives us multiparametric statistics on individual characteristics of a population or red blood cells. Show more

Keywords: Erythrocyte, Laser anemometry, microscope

DOI: 10.3233/BIR-1982-19504

Citation: Biorheology, vol. 19, no. 5, pp. 621-629, 1982

Authors: Oxlund, H. | Manthorpe, R.

Article Type: Research Article

Abstract: The influence of long term systemic glucocorticoid treatment and food restriction on the mechanical properties of muscle tendons and skin was investigated. A group of male, albino rabbits received prednisolone intramuscularly for 63 days. Another group was food restricted to achieve the same weight loss as the prednisolone treated group. The untreated control group had free access to food and water. Peroneus tertius and longus tendons and strip specimens of lumbal skin were tested in a materials testing machine. Long term prednisolone treatment reduced the dry weights of the muscle tendons, with no change in collagen content and “stress”-strain parameters. …The elastic stiffness measured after exhaustion of the viscosity in the tendons was found to be increased. The collagen content of skin was reduced, which resulted in a weakening of the skin as such. However, the extensibility of the skin strips was reduced and the maximum “stress” value, i.e. load value normalized to collagen content, was increased. The food restriction did not change the mechanical properties of muscle tendons. For skin the collagen content was reduced and so were the maximum load and “stress” values after food restriction. It is concluded that both long term glucocorticoid treatment and food restriction reduce the amount of collagen and strength of skin, consistent with clinical experiences. However, in long term glucocorticoid treatment the remaining collagen has increased stability, probably caused by a changed cross-linking pattern, in contrast to a reduced stability of skin collagen in food restriction. Skin is thus influenced more easily than muscle tendon. Show more

DOI: 10.3233/BIR-1982-19505

Citation: Biorheology, vol. 19, no. 5, pp. 631-646, 1982

Authors: Malher, E. | Martin, D. | Duvivier, C. | Volochine, B. | Stoltz, J.F.

Article Type: Research Article

Abstract: Electrical phenomena of cell membranes may be examined by means of cell electrophoresis. Direct microscopic techniques are tedious, inaccurate and rarely, reproducible. Therefore, the authors have developed a new device using Doppler velocimetry. After describing the apparatus, they propose two methods for testing treatment against electroosmosis and present the first biological applications on mixed populations of red cells.

Keywords: Cell electrophoresis, laser velocimetry, zeta potential

DOI: 10.3233/BIR-1982-19506

Citation: Biorheology, vol. 19, no. 5, pp. 647-654, 1982

Article Type: Correction

DOI: 10.3233/BIR-1982-19507

Citation: Biorheology, vol. 19, no. 5, pp. 655-655, 1982

Article Type: Announcement

DOI: 10.3233/BIR-1982-19508

Citation: Biorheology, vol. 19, no. 5, pp. 657-667, 1982