Biorheology - Volume 29, issue 2-3

Authors: Fisher, T.C. | Wenby, R.B. | Meiselman, H.J.

Article Type: Research Article

Abstract: The Cell Transit Analyser (CT A) provides a means to rapidly measure the deform ability of large numbers of individual cells. It combines many of the advantages of micropipette studies with the simplicity and speed of filtrometry methods by measuring the duration of each resistive pulse generated as a cell passes through one of 30 identical micropores in a membrane. However, in our opinion, the potential of the system is limited by the microcomputer and software supplied for data analysis. We have therefore written new software for a more-powerful microcomputer to examine the shape of each resistive pulse rather than …just the duration. Seven new parameters are derived, which provide additional information regarding the passage of cells through the pores. In particular, the contribution of the entry and exit phases of the cell transit are evident in the rise time and fall time of the pulses. The software is user-friendly and allows the analysis of each pulse to be reviewed, which aids understanding of the system and helps to avoid errors in interpreting the data. Show more

Keywords: Cell Transit Analyser, CTA, deformability, filtration, RBC

DOI: 10.3233/BIR-1992-292-301

Citation: Biorheology, vol. 29, no. 2-3, pp. 185-201, 1992

Authors: Müller, G.H. | Schmid-Schönbein, H. | Meiselman, H.J.

Article Type: Research Article

Abstract: Several previous studies have shown that exposure of RBC to temperatures in the range 47 to 48.8°C causes an irreversible alteration of RBC rheological properties; membrane elasticity and viscosity are both increased and greater pressure is required for RBC entry into pipettes. While it has been tacitly assumed that these rheologic alterations are membrane specific, no data on heat-treated hemoglobin (Hb) solutions appear to exist. The present study was thus designed to evaluate the effects of heat-treatment (48.8 ± 0.1°C, 3 to 20 min) on the viscoelasticity of Hb solutions (30 to 45 g/100 ml) prepared from normal human RBC. …Measurements of the viscous component (VC) and elastic component (BC) were made at 25°C using Couette (GDM) and capillary (OCR-D) rheometers; shear rates ranged from 1 to 200 s−1 . All unheated Hb solutions were Newtonian and did not exhibit elasticity. However, after 3 min of heating, an elastic component was measurable. Both VC and EC increased with heating time in a power law fashion. VC continued to exhibit Newtonian behavior, whereas the magnitude of EC was an inverse function of shear rate and directly related to Hb concentration and treatment time. A relaxation function applied to our data suggests a first order reaction. These results indicate that both cytoplasmic and membrane viscoelasticity should be considered in order to fully comprehend the rheologic behavior of heat-treated RBC. Show more

Keywords: Heat-treatment, hemoglobin solutions, viscoelasticity, gelation

DOI: 10.3233/BIR-1992-292-302

Citation: Biorheology, vol. 29, no. 2-3, pp. 203-216, 1992

Authors: Uyesaka, Nobuhiro | Hasegawa, Setsuo | Ishioka, Noriaki | Ishioka, Reiko | Shio, Hideo | Schechter, Alan N.

Article Type: Research Article

Abstract: The effect of superoxide anions (O 2 − ) on red blood cells (RBC) deformability and membrane proteins was investigated using hypoxanthine-xanthine oxidase system. Exposure of RBC to O 2 − caused a marked decrease in RBC deformability with a concomitant increase in cell volume and shape changes. The RBC exposed to O 2 − also displayed pronounced degradation of membrane proteins such as band 3 protein and spectrin; new bands of low molecular weight products appeared as the original …membrane proteins tended to diminish, without the appearance of high molecular weight products. Since the membrane proteins are involved in processes regulating membrane properties such as permeability and viscoelasticity, the decreased deform ability induced by O 2 − may be attributable to changes in membrane proteins. Interestingly, resealed ghosts exposed to O 2 − did not show any significant change in membrane proteins, which suggests the existence of further generation of O 2 − and subsequent production of other active oxygen species mediated by O 2 − -initiated autoxidation of hemoglobin in intact RBC. Furthermore, electrophoretic analysis suggested that active oxygens increased the endogenous proteolytic susceptibility of RBC. In conclusion, a close linkage was suggested between RBC deformability and the membrane proteins. Show more

Keywords: red blood cells (RBC), superoxide anion, deformability, membrane protein, band 3 protein

DOI: 10.3233/BIR-1992-292-303

Citation: Biorheology, vol. 29, no. 2-3, pp. 217-229, 1992

Authors: Mellema, J. | Holterman, H.J. | Waterman, H.A. | Blom, C. | ’s-Gravenmade, E.J.

Article Type: Research Article

Abstract: In this study rheological properties of aqueous solutions of mucin, albumin and mucin-albumin have been investigated in search for saliva substitutes. They were compared with commercially available saliva substitutes on the one hand and natural human saliva on the other hand. For the latter a few measurements on saliva are reported here in addition to previously reported measurements done in our laboratory. Proteins adsorb at the interface and saliva proteins do so strongly and rapidly. Therefore rheological measurements were carried out on the interface and on the bulk underneath the layer. In both cases the flow curve and the complex …viscosity was determined. The results show that specific mucin-albumin solutions were rheologically similar to human whole saliva with respect to both bulk liquid and surface properties. The rheological properties of commercial saliva substitutes were essentially different from those of human saliva. It is concluded that mucin-albumin solutions have good perspectives as saliva substitutes. Show more

Keywords: saliva, human, rheology, mucin, protein adsorption

DOI: 10.3233/BIR-1992-292-304

Citation: Biorheology, vol. 29, no. 2-3, pp. 231-249, 1992

Authors: Yamaguchi, Saburo | Yamakawa, Takashi | Niimi, Hideyuki

Article Type: Research Article

Abstract: Two diameters of vessel and red cell column in cerebral microvessels (> 29.8 μ m in diameter) of cat were measured together with red cell velocity, using a two fluorescent tracer method. A fluorescein isothiocyanate (FITC)-labelled red cell was adopted as a flow tracer to measure the cell velocity with a dual window technique. Based on the fluorescence image, the red cell column diameter was measured. Plasma was stained with rhodamine-B isothiocyanate (RITC)-labelled dextran to measure the vessel diameter. The thickness of the cell-free plasma layer could be determined from the difference of the two diameters. The obtained thickness of …the cell-free layer was not described by a simple function of vessel diameter or red cell velocity; it was dependent on the pseudo shear rate defined by the ratio of cell velocity to vessel radius. The layer thickness increased with a decrease in the pseudo shear rate. Show more

Keywords: cell-free layer, red cell velocity, pseudo shear rate, cerebral microcirculation, intravital fluorescence microscopy

DOI: 10.3233/BIR-1992-292-305

Citation: Biorheology, vol. 29, no. 2-3, pp. 251-260, 1992

Authors: Mayer, J. | Pospíšil, Z. | Litzman, J.

Article Type: Research Article

Abstract: The authors deduced the equation that describes the sedimentation of erythrocytes as the function of time, hematocrit, hemoglobin and some plasma protein concentrations and the citrate viscosity and density. This values served to describe plasma and erythrocyte density, plasma viscosity, erythrocyte aggregation and the influence of suspension concentration on the erythrocyte sedimentation rate. The influence of citrate on blood dilution (the reduction of hematocrit and plasma protein concentrations) was also considered. A good agreement between the observed and predicted values was obtained.

Keywords: Erythrocyte sedimentation rate, Erythrocyte aggregation, Viscosity, Density, Rheology

DOI: 10.3233/BIR-1992-292-306

Citation: Biorheology, vol. 29, no. 2-3, pp. 261-271, 1992

Authors: Lacour, F. | de Ficquelmont-Loizos, M. Marie | Caprani, A.

Article Type: Research Article

Abstract: Adsorption of bovine serum albumin onto glassy carbon is investigated by analysing the time-variation of the double-layer capacitance recorded during the adsorption process. The effect of shear rate is investigated under laminar conditions in a Couette flow. Stationary and sinusoidally modulated values of the shear rate are imposed over the (0–200 s−1 ) range. The flow conditions are shown to play an essential role by markedly modifying the rate of all the steps (three at most) involved in the adsorption mechanism. Moreover, the structure of the adsorbed layers in the intermediate and final states are also strongly modified, an increase …of the shear rate increasing the interaction between the protein and the electrode. Piezoelectric properties of albumin are invoked to account for the experimental results. Show more

Keywords: Bovine Serum Albumin, Glassy Carbon, Couette Flow, Shear Rate, Adsorption, Kinetics, Piezoelectricity

DOI: 10.3233/BIR-1992-292-307

Citation: Biorheology, vol. 29, no. 2-3, pp. 273-284, 1992

Authors: Braga, P.C. | Allegra, L. | Dall’Oglio, G. | Angelini, M. | Mocchi, A.

Article Type: Research Article

Abstract: Changes in production and in physico-chemical properties of bronchial mucus is a common denominator of many pulmonary diseases. A rheometer with innovative features aimed at bronchial mucus routine investigation in clinical practice at the bedside of the patient has been designed. Searle-type configuration with a coaxial cylinder sensor system and the Mooney-Ewart geometry has been adopted. Another new feature is that bob and cup are disposable. Dynamic viscoelasticity is calculated through a microprocessor with specific software and by means of a magnetic torque—motor electronically driven by the microprocessor. The self-zeroing procedure and the autorange greatly simplify the measuring-cycle which is …driven by only one switch. Data (η and G′) are automatically printed on paper. The whole measuring-cycle at the bedside of the patient takes 3–5 min, so that in 1h about 12 samples can be investigated. Show more

Keywords: Innovative rheometer, hospital use, disposable bob + cup, mucus rheology, visco-elasticity

DOI: 10.3233/BIR-1992-292-308

Citation: Biorheology, vol. 29, no. 2-3, pp. 285-293, 1992

Authors: Hallows, Kenneth R. | Frank, Robert S.

Article Type: Research Article

Abstract: We measured changes in the deformability of human pro myelocytic leukemic (HL-60) cells induced to differentiate for 5–6 days along the granulocyte pathway by 1.25 % dimethylsulfoxide (DMSO). Differentiation resulted in an approximately 90 % reduction in the transit times of the cells through capillary-sized pores over a range of aspiration pressures. Cell volume, as measured by two methods, decreased by an average of 35 %. To account for the contribution of the volume decrease to the decrease in transit time, the liquid drop model, developed to describe neutrophil deformability, was used to calculate an apparent viscosity of the cells …during this deformation. The apparent viscosity of both uninduced and induced HL-60 cells was a function of aspiration pressure, and an approximately 80 % reduction in viscosity occurred with induction, as determined by regression analysis. The deformation rate-dependent viscosities of the induced cells were between 65 and 240 Pa-sec, values similar to those measured for circulating neutrophils. To assess the role of polymerized actin in these viscosity changes, intracellular F-actin content was measured, and the effect of dihydrocytochalasin B (DHB), an agent that disrupts actin polymerization, was determined. Despite the significant decrease in cellular viscosity, F-actin content per cell volume did not change significantly after induced differentiation. Treatment with 3 and 30 μ M DHB lowered cellular F-actin content in a dose-dependent manner in both uninduced and induced cells. Cellular viscosity of both uninduced and induced cells decreased sharply with 3 μ M DHB treatment (85 % and 76 % respectively). 30 μ M DHB treatment caused a further significant reduction in the viscosity of uninduced cells, but for induced cells the additional decrease in viscosity was not significant. These data indicate that reductions in both cell volume and intrinsic viscosity contribute to the increased deformability of HL-60 cells with DMSO-induced differentiation. However, changes in the concentration of F-actin cannot account for the decrease in cellular viscosity that occurs. Show more

Keywords: HL-60 cells, deformability, differentiation, F-actin, cell volume, cytochalasins

DOI: 10.3233/BIR-1992-292-309

Citation: Biorheology, vol. 29, no. 2-3, pp. 295-309, 1992

Authors: Nakamura, Masahide | Satake, Nobuaki

Article Type: Research Article

Abstract: As a model of the flow through the false lumen of the dissecting aortic aneurysm, the starting and stopping flows of the Casson fluid through the eccentric circular tube are studied numerically. The calculations are performed by using the one-direction fully developed unsteady flow model. The calculation results show that the non-Newtonian property of the Casson fluid has the following two effects. One is the decrease in the flow rate through the false lumen, the other is the effect to strengthen the non-uniformity of the velocity distribution in the false lumen. Moreover, the calculations based on a triphasic waveform measured …by McDonald are performed and the development of the dissecting aortic aneurysm is discussed on the basis of the calculated wall shear stress. Show more

Keywords: eccentric circular tube, unsteady flow, Casson fluid, finite element method

DOI: 10.3233/BIR-1992-292-310

Citation: Biorheology, vol. 29, no. 2-3, pp. 311-322, 1992