Biorheology - Volume 23, issue s1

Authors: Radtke, H. | Roggenkamp, H.G. | Wolf, S. | Mrowietz, Ch. | Kiesewetter, H.

Article Type: Research Article

Abstract: A new experimental method is described which permits estimation of flow ability of blood: measuring the yield shear stress with the erythrocyte-stasis-meter (ESM). This method is based on the phenomenon that pathological blood under low pressure behaves like a solid body. Knowing the pressure difference at the transition point from solid to fluid behavior and the geometry of the channel, the yield shear stress can be calculated.

DOI: 10.3233/BIR-1984-23S111

Citation: Biorheology, vol. 23, no. s1, pp. 75-77, 1984

Authors: Ravey, J.C. | Ikemoto, S. | Stoltz, J.F.

Article Type: Research Article

Abstract: Blood suspensions have been studied by using an air-bearing viscosimeter which is driven by a rotating magnetic induction. Each transient motion (rise, relaxation with zero or intermittent field) can be considered as a quasi-static motion, from which the curve viscosity-shear gradient can be obtained. Combining several transient motions allows an easier determination of the parameters describing a non newtonian fluid like blood.

Keywords: Viscosimeter, blood rheology, transient flow

DOI: 10.3233/BIR-1984-23S112

Citation: Biorheology, vol. 23, no. s1, pp. 79-82, 1984

Authors: Brancher, J.P. | Lucius, M. | Bernardin, D. | Raihani, R. | Stoltz, J.F.

Article Type: Research Article

Abstract: The viscometer described in this paper comprises a vertical cylinder containing the fluid to be tested and an inner, hollow cylinder floating in the fluid and filled with magnetic liquid. The magnetic liquid and inner cylinder are set in motion by applying a rotating magnetic field. Torque is balanced by the stresses in the fluid and the inertia of the rotating cylinder. The main characteristics of this new apparatus are: - possibility of applying various torques to the rotor. Measurements of angular velocity are made on the inner cylinder (in general, conventional viscometers are built on the opposite principle), …- study in transient flow. Various measurements on Newtonian fluids (water, plasma, oils, etc.) and on blood suspensions have made it possible to improve the accuracy of the method. Show more

Keywords: Viscometer, Magnetic liquid, blood

DOI: 10.3233/BIR-1984-23S113

Citation: Biorheology, vol. 23, no. s1, pp. 83-88, 1984

Authors: Doffin, J. | Perrault, R. | Garnaud, G.

Article Type: Research Article

Abstract: A falling ball viscometer is used to measure whole blood and plasma viscosities. The principle of the device is to determine the fall time of a ball contained in a disposable syringe; the periodic run of the sphere prevents blood sedimentation during the measuring cycle but does not prevent the aggregation process which takes place with a short relaxation time. The analysis of the flow field is discussed relative to previous papers. The study of the dynamics of the falling ball provides two characteristic rates of deformation for the mixed extensional and shear flow field. The Reynolds numbers are calculated …using different velocities and radii. Results on blood and plasma viscosity of patients suffering from rheumatoid arthritis are given in relation with clinical and biological indexes. Show more

Keywords: viscosity, viscometer, blood, rheumatoid, arthritis

DOI: 10.3233/BIR-1984-23S114

Citation: Biorheology, vol. 23, no. s1, pp. 89-93, 1984

Authors: Adjizian, J.C. | Droulle, C. | Osterman, G. | Pignon, B. | Potron, G.

Article Type: Research Article

Abstract: We have studied some rheological parameters in different clinical status by using two coaxial viscometers. The Contraves Low Shear sinus 30 allows available shear rates range from γ ˙ (128s-1 to 0.0175 s-1), and the parameters studied were viscoelastiticy, thixotropy and blood viscosity. The Ecktacytometer1 1 Technicon is another method for measuring cell deformation in couette flow. The aim of our study was to compare these two technics, to consider their clinical interest and finally to visualize an eventual correlation. Technicon

Keywords: blood viscosity, blood thixotropy, blood viscoelasticity, erythrocyte deformability, diffractometry

DOI: 10.3233/BIR-1984-23S115

Citation: Biorheology, vol. 23, no. s1, pp. 95-97, 1984

Authors: Matrai, A. | Flute, P.T. | Dormandy, J.A.

Article Type: Research Article

Abstract: Aggregation and sedimentation of the red cells in the viscometer makes it difficult to obtain good reproducibility at low shear rates. A simple method is described to obtain repeatable torque-time curves with the Contraves LS30. Before starting rotation, the blood sample is agitated by an up and down movement of the bob. This results in identical (within 1-2% of the actual amplitude) repeated tracings even at the lowest shear rates, even with extremely time-dependent samples. The subsequent torque-time curve of the disaggregated and unsettled samples provides an experimental basis for the quantitave description of blood viscoelasticity and for dynamic analysis …of red cell aggregation: furthermore it results in more accurate measurements when comparing different samples and testing therapeutic effects. The method is applicable to any coaxial cylinder type viscometer with manual lowering of the bob. Show more

Keywords: Low shear viscometry, aggregation, sedimentation, time dependence

DOI: 10.3233/BIR-1984-23S116

Citation: Biorheology, vol. 23, no. s1, pp. 99-101, 1984

Authors: Matrai, A. | Warburton, B. | Dormandy, J.A.

Article Type: Research Article

Abstract: The weak interactions between plasma proteins are of possible importance both in haemorheology and in the pathology of several diseases. The use of surface rheology is a convenient way to study the forces arising between surface adsorbed protein molecules. A surface rheological measuring head has been designed for the Contraves LS-30 viscometer. Plasma samples of healthy human subjects showed a rapidly developing viscous surface layer with a mean peak value of 2.10−3 Ns/m surface viscosity at 30–60 seconds. After that the viscosity of the surface layer gradually decreased to zero between 8–20 minutes. The rate of the observed decrease …was not related to shearing. There was no difference between samples anticoagulated with heparin or EDTA. The time course of the described phenomenon coincides with that of thrombocyte and white cell adherence to solid surfaces exposed to plasma. Show more

Keywords: surface rheology, plasma-air interface

DOI: 10.3233/BIR-1984-23S117

Citation: Biorheology, vol. 23, no. s1, pp. 103-105, 1984

Authors: Maurice, G. | Lucius, M. | Stoltz, J.F.

Article Type: Research Article

Abstract: The determination of a constitutive law of a fluid, the red blood can be obtained by fitting the parameters of a theorical law with experimental results. For an experience, several expressions can be agreed, each of them explain a particular property. The aim of my purpose is to describe some mathematical ans numerical methods, in relation with two experiences, able to give the value of an unknown quantity by computation and to fit it with measured quantity. The first method use finite element to modelize a couette nonlinear flow. It can be approach by a very simple model using only …the computation of a nonlinear differential equation. The second use the perturbation method and the expansion in power serie. Show more

Keywords: Blood, Viscosimeter

DOI: 10.3233/BIR-1984-23S118

Citation: Biorheology, vol. 23, no. s1, pp. 107-110, 1984

Authors: Whittington, R.B. | Harkness, J.

Article Type: Research Article

Abstract: This work was done as the first part of a continuing study of neonatal blood. In a recent paper (1), two parameters, “A” (relative whole-blood viscosity at unit rate of shear and 1% haematocrit) and “β ” (shear-sensitivity exponent) were proposed, as characteristics of a given blood-sample. Here, some 60 placentae yielded (after plasma-manipulation) 130 sub-samples having haematocrits ranging from 3% to 90%. Their viscosities were measured in a capillary viscometer set for a constant wall shear-stress of 1855 mPa. “A” and “β ” were calculated by the method given in (1). Multiple calculations on a number of …sub - samples revealed systematic variations within anyone blood; but when every A/β ratio is plotted against the corresponding A, the results follow a smooth curve. This curve occupies a striking, almost central location when A-and-β values from adult normal and pathological bloods (rotational viscometry) are superimposed on the diagram. An analytic form for the close correlation between haematocrit and relative placental blood-viscosity is given by the adoption of a single “group A” and “group β ” for all 130 results. Show more

Keywords: Placental-blood viscosity, haematocrit, shear

DOI: 10.3233/BIR-1984-23S119

Citation: Biorheology, vol. 23, no. s1, pp. 111-114, 1984

Authors: Jung, F. | Roggenkamp, H.G. | Körber, N. | Schneider, R. | Kiesewetter, H.

Article Type: Research Article

Abstract: A new capillary viscometer was developed to eliminate the measuring errors due to insufficient cleaning or the residue of cleaning solution in the capillary. A disposable polyurethane tube which can be discarded after each determination is used as a measuring chamber. This device has been constructed for bed-side application (light weight, dry, thermostat-controlled measuring capillaries, short measuring period, automated process, and easy operation). The Pearson correlation coefficient for comparative measurements with the Coulter-Harkness viscometer was r = 0.979 .

DOI: 10.3233/BIR-1984-23S120

Citation: Biorheology, vol. 23, no. s1, pp. 115-117, 1984

Authors: Duvivier, C. | Didelon, J. | Arnould, J.P. | Zahm, J.M. | Puchelle, E. | Kopp, C. | Obrecht, B.

Article Type: Research Article

Abstract: In clinical practice, a wide variety of drugs are given to modify the rheological properties of bronchial mucus but they are frequently not correctly chosen because there is not a simple apparatus available for the routine measurement of the mucus viscoelasticity. We designed a new viscoelastometer which is easy to operate and permit accurate measurement of the viscoelastic properties of mucus. The system has a Couette geometry and requires a sample of 1 ml. The outer cylinder is thermostated and rotates at a constant rate. The resulting torque is measured on the inner cylinder using a microdisplacement transducer. The …inner cylinder is suspended by a special wire system which maintains a constant 0.75 mm gap between the two cylinders. The apparent viscosity is calculated up to 100 Pa.s. at a low shear rate (0.4 s−1 ) and the elasticity is analyzed by a stress relaxation method The characteristics of the apparatus and the typical viscoelasticity behaviour of several sputum samples are reported. Show more

Keywords: rheology, viscoelastometer, bronchial mucus

DOI: 10.3233/BIR-1984-23S121

Citation: Biorheology, vol. 23, no. s1, pp. 119-122, 1984

Authors: Arnould, J.P. | Zahm, J.M. | Pottier, G. | Duvivier, C. | Puchelle, E.

Article Type: Research Article

Abstract: Spinability is a rheological parameter which characterizes the property of fluids to be drawn into threads when stretched. It has been shown that this property is of particular importance in the mucus transport process. This paper describes an automatic apparatus which measures the spinability of a calibrated volume (2g μ l) of sample at a stretching rate of 10 mm.sec−1 . The reproducibility of the measurements is analyzed on mucus simulants and on different types of bronchial mucus. Using this technique, we observed that the spinability of bronchial secretions is significantly correlated (r = 0.69, p < 0.001) with …their transport rate measured on the depleted frog palate. This device is suitable for measuring the spinability of all conductive types of mucus and other biological fluids. Show more

Keywords: Respiratory mucus, thread-forming property, spinability, mucociliary transport

DOI: 10.3233/BIR-1984-23S122

Citation: Biorheology, vol. 23, no. s1, pp. 123-126, 1984

Authors: Bell, Alan E. | James, Stuart L. | Marriott, Christopher

Article Type: Research Article

Abstract: In order to rationally test the efficacy of mucolytic and mucospissic compounds, their effects upon mucus viscoelasticity, ciliary beat frequency (c.b.f.) and total mucociliary transport rate (t.t.r.) must all be determined. Methods are described which allow the measurement of the viscoelastic modulii of small (10μ L) quantities of mucus, while c.b.f. and t.t.r. are determined using the frog palate model.

Keywords: mucus, mucociliary, mucolytic, viscoelasticity

DOI: 10.3233/BIR-1984-23S123

Citation: Biorheology, vol. 23, no. s1, pp. 127-130, 1984

Authors: Koyama, T. | Nitta, J. | Asakura, T. | Ushizaka, T. | Aizu, H. | Kikuchi, Y.

Article Type: Research Article

Abstract: A velocimeter for measurements of blood flow velocity in microvessels was constructed with a microscope, a grating, a photomultiplier and a wave-period measuring circuit. A differential detection system seemed to be useful when the probing area was extremely small. A pulsating flow velocity contour and the velocity reduction caused by an application of noradrenaline were on-line recorded in an arteriole of foot web of frogs.

Keywords: Grating laser microscope, differential detection, blood flow velocity, microvessels

DOI: 10.3233/BIR-1984-23S124

Citation: Biorheology, vol. 23, no. s1, pp. 131-134, 1984

Authors: Braasch, D.

Article Type: Research Article

Abstract: Capillary blood flow may be considered as the flow of two compartments a.) the low viscous cell free marginal layer, surrounding b.) the higher viscous axial core. If the flow of both compartments is calculated separately according to Poiseuille, the addition of the two calculations allows to adapt Poiseuille’s law to the non-Newtonian blood flow in small capillaries. The modified law correlates theoretical and experimental data with R2 =0.99. (H=0.3–0.7, τ W =0.1–1.2 Pa, blood viscosity 5 to 20 mPa·s, capillary I.D. 0.3 mm). The width of the marginal was calculated by relating the shear dependent change in electrical …resistance in blood perfused capillaries to the development of a cell free marginal layer. The viscosity of the core was determined with a bended glass fibre (⌀= 10 μ m). Show more

Keywords: Viscosity, marginal layer, axial core, Poiseuille’s law

DOI: 10.3233/BIR-1984-23S125

Citation: Biorheology, vol. 23, no. s1, pp. 135-143, 1984

Authors: Slaaf, Dick W. | Tangelder, Geert Jan | Reneman, Robert S.

Article Type: Research Article

Abstract: Blood platelets labeled in vivo with the fluorochrome acridine red can be localized objectively within a thin optical section, using fluorescence microscopy. This allows the study of the rheological behavior of platelets in vivo as exemplified by the assessment of the concentration distribution and the orientation of platelets flowing in small arterioles of the rabbit mesentery.

Keywords: blood platelets, rheology, in vivo, fluorescence

DOI: 10.3233/BIR-1984-23S126

Citation: Biorheology, vol. 23, no. s1, pp. 145-149, 1984

Authors: Bitoun, J.P. | Ly, D.P. | Bellet, D.

Article Type: Research Article

Abstract: This text recalls the main sequences of a videofilm in which we have looked at the blood flow through small diameter tubes, varying from 200 to 500 μ m diameter, using a video equipment where the camera is fixed to a phase contrast microscope. Flows of two fluid model through converging-diverging small tubes have been studied both theoretically and experimentally, where we have considered the influence of tube diameter, stenosis, flow rate, haematocrit upon the red blood cells repartitions and the thickness of peripheral plasma layer.

DOI: 10.3233/BIR-1984-23S127

Citation: Biorheology, vol. 23, no. s1, pp. 151-153, 1984

Authors: Kiesewetter, H. | Mrowietz, C. | Lazar, H. | Jung, F.

Article Type: Research Article

Abstract: An instrument was developed which can simultaneously determine the hematocrit and the total electrolyte concentration in blood and plasma respectively. It is possible to correct the hematocrit value for fluctuations of the total electrolyte concentration. Pilot studies of this device have been conducted on physiological and rigid erythrocyte suspensions and on plasma with various total electrolyte concentration. In the future, this device will be employed in analyzing blood and plasma of patients undergoing hemodialysis.

DOI: 10.3233/BIR-1984-23S128

Citation: Biorheology, vol. 23, no. s1, pp. 155-157, 1984

Authors: Bauer, R. Dietrich

Article Type: Research Article

Abstract: A fundamental problem of haemodynamics lies in the description of the rheological properties of arteries. The time and history dependency of stress and strain, the nonlinearity of the stress-radius relationship, and the activity of vascular smooth muscle complicate or even prevent a complete mathematical characterization of the arterial wall mechanics. Due to this nonlinearity, dynamic investigations were hitherto performed in excised arteries in vitro by means of small sinusoidal changes of stress and radius at different stress levels in a wide frequency range. To allow an analysis of the dynamic rheological properties of arteries in vivo, we have developed a …procedure which permits the separate determination of the elastic, the viscous, and the inertial forces acting on the arterial wall. The stress can be subdivided into an elastic stress which is a function of radius (r), a viscous stress which is a function of dr/dt, and an inertial stress which is a function of d2 r/dt2 . These stresses are formulated as polynomials. Under cyclic loading and unloading, hysteresis loops appear in the stress-radius diagrams of arteries. Since the elastic stress-radius diagram must be free from any loop, the coefficients of the viscous and the inertial stress can be found by a fitting procedure, using the criterion of loop elimination. Investigations were performed on exposed canine arteries in vivo. The main result was that the elastic stress-radius curve was markedly nonlinear at greater pulse pressures. The viscous wall behaviour, too, was nonlinear and depended mainly on the square of the vessel radius. Show more

Keywords: Arterial elasticity, arterial wall viscosity, arterial stress-radius relationship

DOI: 10.3233/BIR-1984-23S129

Citation: Biorheology, vol. 23, no. s1, pp. 159-167, 1984

Authors: Johnson, Marvin | Katz, J. Lawrence

Article Type: Research Article

Abstract: Bone has been shown to be a viscoelastic material which is thermorheologically complex. This implies that multiple mechanisms determine the viscoelastic response of bone. New calculations of the contribution of fluid flow to the viscoelastic behavior of bone have been made. The calculation of the relaxation time was based on Biot’s model for the relaxation of fluid flow in porous materials while the relaxation strength was estimated from simple composite models. These models together with recent measurements of the permeability of bone predict that part of the relaxation due to fluid flow will occur at fairly high frequencies, perhaps above …10 kHz for in vitro samples. Measurements of ultrasonic wave propagation and attenuation in wet bone have been performed from 0.5 MHz to 15 MHz and the mechanical damping was measured from 100 Hz to 1 kHz with fluid viscosities ranging from 10−3 to 5 × 10−2 (MKS). However, a complete understanding of the rheological properties or bone will require additional experiments to bridge the gap between the low frequency measurements and the ultrasonic measurements. Show more

DOI: 10.3233/BIR-1984-23S130

Citation: Biorheology, vol. 23, no. s1, pp. 169-174, 1984

Authors: Lorente, Paco | Azancot, Isaac | Masquet, Christiane | Adda, Jean-Luc | Saumont, Rémi | Slama, Robert

Article Type: Research Article

Abstract: Regional wall motion of the left ventricle (LV) has been analyzed from contrast ventriculograms by using 4 methods based on different geometrical frameworks. Two of them utilize moving internal reference systems, the center of mass (CMM) and the long axis (LAM) methods; the two other ones use fixed external reference systems, the area-based (ABM) and the Palo Alto (PAM) methods. The techniques were applied on a set of 81 patients: 42 were normal and composed the group I; 22 had a single vessel obstruction >75% of the left anterior descending coronary artery (group II) with old necrosis or active ischemia …of the LV anterior wall; 17 had a single vessel obstruction >75% of the right coronary artery (group III) with old necrosis or active ischemia of the LV inferior wall. ABM and PAM showed the highest specificities and sensitivities on the studied sample. Therefore, we believe these two methods, of the techniques tested, are the best to quantitate wall motion from cineangiograms. Show more

Keywords: Left ventricular wall motion, cineangiography, computer-based analysis methods

DOI: 10.3233/BIR-1984-23S131

Citation: Biorheology, vol. 23, no. s1, pp. 175-182, 1984

Authors: Geiger, D. | Trevisan, D. | Bercovy, M. | Oddou, C.

Article Type: Research Article

Abstract: Up to now, not so much attention has been paid concerning the dynamic rheological behaviour of soft tissues although non linear viscoelastic effects have often been reported when mechanical properties of biomaterials are concerned. In order to characterize such properties different rheological tests have been proposed, the two principal being the study of the sample stresses responses to applied strains which are either harmonic with time or of step function type. Two different apparatus have been designed in our laboratory which allow specific rheological tests on biological materials under controlled environmental conditions. With one of them, harmonic uniaxial extension …tests are performed in a large domain of frequencies (.001 Hz to 100 Hz) and forces (up to 20 daN); with the other, the samples are submitted to relaxation tests in uniaxial elongation up to 5 cm deformation within time duration of the order of 20 ms. The principal characteristics, limitations and performances of such apparatus are presented and few examples of data thus obtained are given. On the basis of quasi linear viscoelasticity models, it can be shown that both two types of tests with their proper limitations are leading to the same rheological parameters. Show more

Keywords: Mechanical properties, Viscoelasticity, Biomaterials, Ligaments

DOI: 10.3233/BIR-1984-23S133

Citation: Biorheology, vol. 23, no. s1, pp. 193-200, 1984

Authors: Ehrly, Albrecht M.

Article Type: Research Article

Keywords: tissue oxygen tension, intermittent claudication, hemorheologic drugs

DOI: 10.3233/BIR-1984-23S134

Citation: Biorheology, vol. 23, no. s1, pp. 201-207, 1984

Authors: Mihailova, A.P. | Petrov, N.K.

Article Type: Research Article

Abstract: A system of equations, describing the excitation-contraction coupling in cardiac muscle is obtained on the basis of a physiological model and of a thermodynamical one of a system with external control, the latter model being proposed by the authors. A single isometric contraction is modelled for latent, activation and relaxation periods. The obtained theoretical results coincide qualitatively with the experimental data.

Keywords: thermodynamic model, cardiac muscle tissue, excitation-contraction coupling

DOI: 10.3233/BIR-1984-23S135

Citation: Biorheology, vol. 23, no. s1, pp. 209-212, 1984

Authors: Kiesewetter, H. | Mrowietz, C. | Lazar, H. | Jung, F.

Article Type: Research Article

Abstract: We have developed a device for the determination of the minimum shear force necessary to maintain complete disaggregation of erythrocytes and to simultaneously determine the hematocrit of blood samples (red cells in autologous plasma). A functional relationship between this shear force and the hematocrit was determined. The first derivative of the (measured) γ Tmin as a function of the hematocrit was found to be identical (within limits) for all normal blood samples tested.

DOI: 10.3233/BIR-1984-23S136

Citation: Biorheology, vol. 23, no. s1, pp. 213-215, 1984

Authors: Ernst, E. | Magyarosy, I. | Roloff, Ch. | Drexel, H.

Article Type: Research Article

Abstract: A viscometric technique is outlined for the measurement of red cell aggregation (RCA). Samples are submitted to a constant shear rate of 2,4 s−1 . The resulting time dependent torque signal reaches a peak soon after starting the rotation and falls within seconds to a constant baseline, thereby describing an area “F” with the baseline. The shear history of the sample being strictly controlled, “F” is reproducible and shows a direct, positive correlation with RCA as determined for instance in the “aggregometer”.

Keywords: hemorheology, red cell aggregation, viscometry

DOI: 10.3233/BIR-1984-23S137

Citation: Biorheology, vol. 23, no. s1, pp. 217-219, 1984

Authors: Stoltz, J.F. | Gaillard, S. | Paulus, F. | Henri, O. | Dixneuf, P.

Article Type: Research Article

Abstract: From a clinical point of view, the approach to erythrocyte aggregate or rouleau formation and cohesion is undeniably of great interest. A large number of methods have been suggested for studying this parameter such as: back-scattering of light, nephelometry, ultrasound, etc... In this paper the authors have compared three methods to approach rouleau formation: direct observation of rouleau formation (rheoscope); ‘erythrocyte aggregometer’: with this technique, the light transmitted by the sample is integrated over a period of time and provides an index (IA ); laser reflectometer based on studying the light that is back-scattered by the blood sheared in the …gap of a viscometer. The results show that the indexes measured by both reflexion and transmission vary according to hematocrit and reach a maximum value at hematocrit levels of between 30 and 40 %. In contrast, observation using the rheoscope did not provide qualitative evidence of this phenomenon. Show more

DOI: 10.3233/BIR-1984-23S138

Citation: Biorheology, vol. 23, no. s1, pp. 221-226, 1984

Authors: Braasch, A.

Article Type: Research Article

Abstract: Flow resistance of EDTA or defibrinized blood was measured in a vertical capillary viscometer. (Capillary I.D. = 0.3 mm, l = 475 mm, τ W = 0.27 to 0.036 Pa). With decreasing shear forces the apparent viscosity increased from 12 to 16 mPa·s, i.e. by about 30%. There was no significant difference in flow resistance between red cells suspended in plasma or serum. The apparent viscosity of the same blood sample increased from 14 to 45 mPa·s for RBC in plasma i.e. by about 320% if measured with a rotational viscometer. The attempt is made to explain this …difference in flow resistance with the different effect of shear resistant RBC-aggregates upon a parabolic streaming profile in a capillary, or upon the quasi linear profile within the annular Gap of a rotational viscometer. Show more

DOI: 10.3233/BIR-1984-23S139

Citation: Biorheology, vol. 23, no. s1, pp. 227-230, 1984

Authors: Roggenkamp, H.G. | Jung, F. | Schneider, R. | Kiesewetter, H.

Article Type: Research Article

Abstract: We present a device for the routine measurement of the deformability of individual red blood cells, the so called Single-Erythrocyte-Rigidometer (SER). The time required for individual erythrocytes to traverse a single pore membrane (pore diameter = 5 μ m, pore length = 25 μ m) is taken as an index of red cell deformability. For example we present the results from patients with insult, polyneuropathy and morbus binswanger. Compared to the results of erythrocytes of healthy probands a significantly increased rigidity of the RBC of the patients can be diagnosed.

Keywords: RBC-Deformability, Single-Erythrocyte-Rigidometer(SER, Single Pore

DOI: 10.3233/BIR-1984-23S141

Citation: Biorheology, vol. 23, no. s1, pp. 241-243, 1984

Authors: Seiffge, D.

Article Type: Research Article

Abstract: Employing the “Singlepore Erythrocyte Rigidometer” (SER) in which small pore diameters were used, significant differences were measured between red blood cells from adjuvant arthritic rats compared to control from non-diseased animals. The results changed to opposite values using higher pore diameters, which may be due to differences in cell “rigidity” and MCV.

Keywords: RBC-Deformability, Single Erythrocyte Rigidometer, Pore Geometry, Passage Time

DOI: 10.3233/BIR-1984-23S142

Citation: Biorheology, vol. 23, no. s1, pp. 245-247, 1984

Authors: Sowemimo-Coker, S.O. | Kovacs, I.B. | Turner, P. | Kirby, J.D.T.

Article Type: Research Article

Abstract: In order to follow the filtration of a red cell suspension with time, the filtration technique described (1) has been modified. The red cell suspension is filtered through a polycarbonate membrane filter (pore diameter 5μ m) under gravitational force. The filtrate is collected in a plastic tube connected to an isometric transducer, the output of Which is registered on a chart recorder. The linear part of the curve obtained is used to calculate the slope and the relative filterability (HF) ie the ratio of the rate of flow of the red cell suspension to the rate of flow of the …suspending medium. The reproducibility of the technique is demonstrated by a <5% coefficient of variation in one blood sample <5% interobserver variation and a weekly variation from the same donor of <5%. The fast filtration rate of a highly diluted red cell suspension (0.5–1%) may be followed with this technique, taking the first 15 seconds to calculate it. The technique has proved useful in detecting differences in red cell deformability in connective tissue disorders (Scleroderma, Raynaud’s phenomenon) also between stored and freshly prepared red cell suspension and its improvement by drugs (pentoxifylline, dipyridamole). Show more

Keywords: Red cell filterability, filtration technique

DOI: 10.3233/BIR-1984-23S143

Citation: Biorheology, vol. 23, no. s1, pp. 249-253, 1984

Authors: Stoltz, J.F. | Duvivier, C. | Malher, E.

Article Type: Research Article

Abstract: The Erythrometer is a new device capable of determining both red blood cell filterability and plasma viscosity. In the case of filterability measurements, a suspension of washed red blood cells is filtered at a steady flow rate through a 3 or 5 μ m pore-diameter membrane. Pressure drop across the membrane is recorded and a red blood cell filterability index can be calculated according to the change in pressure. The authors describe the instrument’s operating principle and performance and present some of the results obtained.

Keywords: Deformability, filterability, red blood cells, plasma, viscosity

DOI: 10.3233/BIR-1984-23S144

Citation: Biorheology, vol. 23, no. s1, pp. 255-259, 1984

Authors: Guéguen, M. | Bidet, J.M. | Durand, F. | Driss, F. | Joffre, A. | Genetet, B.

Article Type: Research Article

Abstract: The authors have tested a new device that records the filtration pressure of a suspension of red blood cells (R.B.C) passing through a 3μ m pore diameter filter. As the flow rate is constant, the pressure increase allows to appreciate an index of the R.B.C deformability. In order to test the performances of this new equipment, the authors have studied the influence of the variation of the following parameters. - Haematocrit from 0.5 to 2%, Buffer composition; time elapsing from drawing to measurement: from hour 0 to hour 3. This analysis has been performed on donors; on packed red cells …preserved in CPD, from D0 to D21 and on patients specimens and the results have been compared to the whole blood filtration according to the Reid and Dormandy method. The following parameters were simultaneously measured: - Whole blood viscosity by means of a Low Shear 30 viscosimeter, Intraerythrocyte ATP by bioluminescence, Membrane lipid composition (cholesterol, phospholipids), Scanning electron microscopy. This new apparatus, measuring the filtration pressure seems to be a more insensitive and reproductible method allowing to approach the RBC deformability, and quite useful in clinical haemorheology. Haematocrit from 0.5 to 2%, Buffer composition; time elapsing from drawing to measurement: from hour 0 to hour 3. This analysis has been performed on donors; on packed red cells preserved in CPD, from D0 to D21 and on patients specimens and the results have been compared to the whole blood filtration according to the Reid and Dormandy method. The following parameters were simultaneously measured: Whole blood viscosity by means of a Low Shear 30 viscosimeter, Intraerythrocyte ATP by bioluminescence, Membrane lipid composition (cholesterol, phospholipids), Scanning electron microscopy. This new apparatus, measuring the filtration pressure seems to be a more insensitive and reproductible method allowing to approach the RBC deformability, and quite useful in clinical haemorheology. Show more

Keywords: Erythrocyte filterability, erythrometer, filtration pressure

DOI: 10.3233/BIR-1984-23S145

Citation: Biorheology, vol. 23, no. s1, pp. 261-265, 1984

Authors: Thao Chan, M. | Catry, E. | Weill, D. | Marcel, G.A. | George, C.

Article Type: Research Article

Abstract: When filtering red blood cells (RBC) resuspended into buffer at constant flow, the pressure-time curve is dependent on erythrocyte deformability (E.D) and also on the plugging of pores by RBC or leukocytes (WBC). To understand the influence of these 3 factors, we used an apparatus with: 1) a constant flow syringe (Bioblock) (1.56 ml/mn); 2) a pressure transducer (Statham P23 ID); 3) a recorder (Gould); 4) a 5 μ m polycarbonate filter (Nuclepore) housed in a lucite block according to Usami & al.(1). Resuspensions of RBC from 4 to 14 % haematocrit with 0 to 600 WBC/mm3 were investigated. Results …indicate that: 1/ The first inflexion point of the pressure-time curve (initial pressure leading to calculation of β ) is related to the RBC’s deformability; 2/β is (in our experimental conditions) dependent on the WBC number; 3/β seems very sensitive to deformability changes as shown by rapid increases induced by osmolarity changes. Show more

Keywords: Deformability, erythrocytes, filterability, leukocytes, osmolarity

DOI: 10.3233/BIR-1984-23S146

Citation: Biorheology, vol. 23, no. s1, pp. 267-270, 1984

Authors: Hanss, M. | Koutsouris, D.

Article Type: Research Article

Abstract: A new version of the Hemorheometre is presented. The main improvements are: 1) The measurements can be performed at constant temperature. 2) The apparatus operation is automated. The accuracy of the apparatus is thus significantly increased.

DOI: 10.3233/BIR-1984-23S148

Citation: Biorheology, vol. 23, no. s1, pp. 275-277, 1984

Authors: Stuart, J. | Lucas, G.S. | Caldwell, N.M. | Kenny, M.W. | Meakin, M. | Aillaud, M.F. | Juhan-Vague, I.

Article Type: Research Article

Abstract: Positive-pressure and initial-flow-rate (Hémorhéomètre) filtration systems were used to study the deformability of erythrocytes from whole blood stored in EDTA or heparin. When all contaminating platelets and leucocytes were removed from the erythrocyte suspension there was no significant anticoagulant effect on erythrocyte filtration. Blood may therefore be stored in K2 EDTA (1.5 mg/ml blood) or lithium heparin (15 IU/ml blood) for up to 6 hours at room temperature prior to measurement of erythrocyte filterability.

Keywords: Rheology, Anticoagulants, Erythrocyte deformability

DOI: 10.3233/BIR-1984-23S149

Citation: Biorheology, vol. 23, no. s1, pp. 279-281, 1984

Authors: Stuart, J. | Kenny, M.W. | Meakin, M. | Lucas, G.S. | Caldwell, N.M.

Article Type: Research Article

Abstract: Posit.ive-pressure and initial-flow-rate (Hémorhéomètre) methods for the study of erythrocyte filtration through 5 μ m diameter pores are highly sensitive to the presence of contaminating leucocytes in the erythrocyte test suspension. A pre-filtration step, in which heparinised or EDTA-anticoagulated whole-blood was passed through a column of Imugard IG500 cotton wool, was therefore developed. This procedure removed contaminating platelets and leucocytes, but not erythrocyte sub-populations, and is likely to improve the sensitivity and specificity of erythrocyte filtration techniques.

Keywords: Rheology, Leukocytes, Anticoagulants, Erythrocyte deformability

DOI: 10.3233/BIR-1984-23S150

Citation: Biorheology, vol. 23, no. s1, pp. 283-285, 1984

Authors: Ravey, J.C. | Mazeron, P.

Article Type: Research Article

Abstract: The physical optics approximation has been used to compute small angle light scattering patterns from spheroids regarded as models for deformed red cells. According to their orientation, diagrams have been obtained whose fine structure can be very different from that resulting of the classical diffraction (existence of maxima and minima of intensity along the rings). Some experimental results for red cells suspensions under shear are shown which exhibit features very similar to the theoretical ones.

DOI: 10.3233/BIR-1984-23S151

Citation: Biorheology, vol. 23, no. s1, pp. 287-290, 1984

Authors: Nossal, Michael P.J.

Article Type: Research Article

Abstract: The Ektacytometer is a visco-diffractometric method to preferentially examine the functional properties of erythrocytes. The realization of this method in the form of an automated laboratory instrument, the Technicon Ektacytometer, is described. A suspension of RBC is submitted to a uniform shear stress. The resulting deformation of the cells is seen as an elongation of the diffraction image and expressed as the Elongation Index or EI. EI may be traced on an X–Y recorder as a function of stress, time and of suspending medium osmolality. The osmolality is varied automatically in the viscometer and automatically measured via its conductivity, resulting …in an “Osmoscan”. The Osmoscan is highly reproducible and requires only 150 μ l of blood and 5 minutes per sample. Its high sensitivity to small changes in erythrocyte properties permits the separation of factors affecting RBC deformability, and provides a measure of the osmotic fragility which correlates very well with the traditional test. Other applications are described, including mechanical fragility assays on whole cells, relaxation times of ghosts and the automatic variation of PO2 . Possible future applications are suggested. Show more

DOI: 10.3233/BIR-1984-23S152

Citation: Biorheology, vol. 23, no. s1, pp. 291-295, 1984

Authors: Berga, L. | Dolz, J. | Vives-Corrons, J.L. | Feliu, E. | Rozman, C.

Article Type: Research Article

Abstract: Erythrocyte deformability is an important determinant of red cell life span and depends on at least three key factors: shape, internal viscosity and membrane mechanical properties. In this paper we describe three viscometric methods for assessing red cell deformability and fragmentation: 1) Plasma and whole blood are sheared with a coneplate viscometer at high shear rates. A mathematical model for liquid behaviour is applied to the results from plasma and whole blood viscosity, and a rheological parameter called internal viscosity is obtained. 2) Shearing packed red cells(Haematocrit ⩾ 95%)at high shear rates, a mechanical fragmentation curve is obtained, and a …new rheological parameter called rupture stress is determined. 3) Shearing whole blood at 230 Sec−1 and increasing continuously the temperature from 37°C to 57°C, a thermic curve is obtained. A viscosity increase is observed at about 48°C and thermic curve changes are related to effects of heat on the red cell membrane. Internal viscosity, mechanical fragmentation curve and thermic curve assess red cell deformability and fragmentation and can be used as diagnostic tools in diseases with red cell abnormalities. Show more

Keywords: Red cell deformability, Red cell fragmentation, Internal viscosity, Red cell membrane

DOI: 10.3233/BIR-1984-23S153

Citation: Biorheology, vol. 23, no. s1, pp. 297-301, 1984

Authors: Stoltz, J.F. | Janot, C. | Saur, F. | Weber, M. | Malher, E. | Duvivier, C.

Article Type: Research Article

Abstract: A new electrophoresis system using Laser Doppler velocimetry has been developed. This technic allows fast measurements (1 minute) over a large number of particles (several thousand or more). Furthermore, the small size of the particles is no longer a limitation of the measurement. These qualities made it possible to study the electrokinetic properties of cells. In this paper the authors present the first application obtained on different types of bacteria (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris) submitted to five antibiotics (gentamycin, minocyclin, cephalotin, spiramycin, sobramycin). After four hours or incubation at 37°C, important decreases of electrophoretic mobility …were observed on bacteria treated with antibiotics to which they were sensitive. On the other hand, no significant modification appeared on bacteria treated with antibiotics to which they were not sensitive. In conclusion, the electrophoretic mobility test seems to be useful to study the response of bacteria to antibiotics and perhaps could be used to set antibiograms. Show more

Keywords: Laser-Doppler electrophoresis, surface charge, bacteria, antibiotics

DOI: 10.3233/BIR-1984-23S154

Citation: Biorheology, vol. 23, no. s1, pp. 303-307, 1984

Authors: Leterrier, François | Berleur, François | Viret, Jacques | Daveloose, Denis

Article Type: Research Article

Abstract: One of the most powerful tools for the study of the molecular dynamics and molecular organization of biological membranes is the spin label method which uses stable free radicals (nitroxides) studied by electron spin resonance spectroscopy. The spectra are very dependent on the mobility and orientation of these probes in a magnetic field. They give information on the tumbling rate of molecules in liquids, the membrane microviscosity, the order parameter of the phospholipid fatty acid chains, the activation energy of their rotation and their flexibility. The method has interesting applications in the rheological domain; for example it enables measurement of …the internal viscosity of erythrocytes and red blood cell orientation in a Poiseulle flow. Show more

Keywords: Spin labelling, RBC internal viscosity, RBC orientation

DOI: 10.3233/BIR-1984-23S155

Citation: Biorheology, vol. 23, no. s1, pp. 309-314, 1984

Authors: Andre, J.C. | Donner, M. | Bouchy, M. | Viriot, M.L. | Jezequel, J.Y. | Stoltz, J.F.

Article Type: Research Article

Abstract: It is possible to characterize the cohesion of the lipidic zones in cells or in membranes by using molecular emission spectroscopy techniques such as: fluorescence polarization, quenching reactions, intramolecular reactions. However, applying these techniques in biology can be improved by the use of pulsed excitations leading to the time-resolved evolutions of some properties of the probe, which can themselves be a function of their environment. The first and the last techniques, based on the use of diphenylhexatriene and dipyrenylpyopane respectively are used in practice by steady state excitation. In the case of fluorescence polarization, it can be shown that …the method can be applied, within certain limits, which have to be precised when studying the modifications in the membranes. This is also partly true for methods based on the use of intramolecular reactions. However these continuous excitation techniques usually only lead to a global result which is a function of several spectroscopic parameters and of the “cohesion” of the membrane. Then it can be shown that to go beyond this step of semi-quantitative analysis, it is necessary to use pulsed or modulated excitation methods. Moreover this more sophisticated technical approach implies a new theoretical effort to understand the molecular dynamics of the membranes. Show more

Keywords: cellular rheology, photophysical methods, fluorescence polarization

DOI: 10.3233/BIR-1984-23S156

Citation: Biorheology, vol. 23, no. s1, pp. 315-322, 1984

Authors: Koyama, T. | Araiso, T. | Shindo, Y. | Arai, T.

Article Type: Research Article

Abstract: A nanosecond fluorometer was designed to study the microdynamics of biomembranes. The overall system consists of a nitrogen laser for excitation of fluorophores, optics consisting of polarizers, monochromators, a single photon counting system having a multichannel time to amplitude converter controlled with a microcomputer and a data processing system. The laser pulse for excitation was polarized with a polarizer. Anisotropically polarized DPH fluorescence could be measured with a time resolution smaller than 5 nsec. The parallel decay curve of DPH fluorescence was higher than the perpendicular decay curve in erythrocyte membrane over the whole decay time. No anisotropism was recorded …in a tetrahydrofuran solution. These results suggested that the motion of DPH molecules in erythrocyte membranes was restrained and that the present system provided information on rheological aspects of molecular dynamic structure of biomembranes. Show more

Keywords: nanosecond fluorometer, erythrocyte membrane, anisotropy, microrheology, wobbling motion, fluorophore

DOI: 10.3233/BIR-1984-23S157

Citation: Biorheology, vol. 23, no. s1, pp. 323-329, 1984

Authors: Viriot, M.L. | Collin, T. | Gaillard, S. | Stoltz, J.F. | Andre, J.C.

Article Type: Research Article

Abstract: Intramolecular excimer formation of dipyrenylpropane was investigated in human blood platelets. The ratio of the emission intensities of excimer to monomer (IE /IM ) is sensitive to changes in lipidic membrane structure, induced by external perturbations, such as cholesteryl hemisuccinate introduction and temperature. Lack of reliable “microviscosities” determinations could be due to poor solubility of the probe in aqueous cells suspensions. Results were compared to those obtained with the fluorescence polarization technique.

Keywords: blood platelets, fluorescence spectroscopy

DOI: 10.3233/BIR-1984-23S158

Citation: Biorheology, vol. 23, no. s1, pp. 331-333, 1984

Authors: Steiner, C.A. | Litt, M. | Nossal, R.

Article Type: Research Article

Abstract: Variables which describe the structure and rheological behavior of macromolecules in both dilute solutions and gels may be determined using methods of quasielastic laser light scattering (QELS). Such parameters include diffusion coefficients, molecular size such as hydrodynamic radius, and viscoelastic moduli. If the polymer is polydisperse, the distribution of radii may be estimated. Application of the methods is illustrated with data on the size distribution of a tracheal mucin glycoprotein solution as an example of a polydisperse polymer solution of biorheological interest. A scheme for measuring shear moduli of polymer gels using dynamic laser light scattering is illustrated with data …on reconstituted fibrin clots. Show more

Keywords: Laser light scattering, mucin structure, gel rheology, fibrin gels

DOI: 10.3233/BIR-1984-23S159

Citation: Biorheology, vol. 23, no. s1, pp. 335-344, 1984

Authors: Peslin, R. | Duvivier, C. | Hannhart, B.

Article Type: Research Article

Abstract: A synthetic approach to lung and chest mechanics is to apply pressure variations to the respiratory system over a range of frequencies and to study the amplitude and phase relationships between applied pressure and resulting gas or tissue flow. Such impedance measurements may be performed in different ways, which are not equivalent: the most usual are to measure gas flow at the mouth while pressure is varied either at the same place (input impedance) or around the chest (transfer impedance). Transfer impedance measurements were performed in healthy subjects from 3 to 70 Hz and tentatively interpreted with a model featuring …tissue elasticity, resistance and inertance, gas compressibility, and airway gas resistance and inertance. The pressure-flow ratio was minimum at 5–10 Hz and increased very fast above 50 Hz. The phase angle was nil around 7 Hz, of + 90° at 30–40 Hz and close to 180° at 70 Hz. The validity of the model is supported by the quality of the fit to the data up to 50 Hz, the values of the coefficients and the results of experiments where the subject’s mechanical properties were varied. Show more

DOI: 10.3233/BIR-1984-23S132

Citation: Biorheology, vol. 23, no. s1, pp. S183-S191, 1984

Authors: Teitel, P. | Malotta, H. | Leschke, M. | Schmid-Schönbein, H.

Article Type: Research Article

Abstract: Nuclepore filter membranes currently utilized to assess RBC “deformability” do not meet the strict metrological requirements of a measuring gauge. They present different kinds of inhomogeneities introducing an useless information (a background noise) into measurement results and expressed as poor reproducibility. Variance reduction can only be achieved by eliminating aberrant results from a series of parallel measurements made with different membranes. To this end a procedure is proposed to identify aberrant values by an iterative statistical regression analysis of data from filter calibration and measurements on RBC suspensions and to express results as “reduced” initial flow rates for a standard …filter resistance. Show more

DOI: 10.3233/BIR-1984-23S140

Citation: Biorheology, vol. 23, no. s1, pp. S231-S240, 1984

Authors: Duvivier, C. | Arnould, J.P. | Malher, E. | Fourneau, C. | Stoltz, J.F.

Article Type: Research Article

Abstract: A device for continuously measuring, at constant pressure, the filtration resistance of different liquid suspensions is described. It is made up of two main parts: flowmeter system and electronic circuit. The flowmeter consists of a capillary tube and a sensitive pressure transducer, and has a time response of 100 ms and a linearity of ± 1 % from 1 μ ls−1 to 200 μ ls−1 . The electronic part allows the calculation and recording of flow versus time and filtration resistance versus the volume which passes through the filter. Principle, technical characteristics of the system and examples of recording …with several Red Blood Cell populations are reported. Show more

Keywords: filterability, erythrocytes, constant pressure

DOI: 10.3233/BIR-1984-23S147

Citation: Biorheology, vol. 23, no. s1, pp. S271-S274, 1984

Authors: Plouvier, S.R. | Huong, Pham V.

Article Type: Research Article

Abstract: The microscopic observation of blood under various pathological circumstances (infectious diseases, cancer, leukemia) shows the presence of blue particles of micrometer size. Microbial cultivation of such blood samples allows the isolation of bacteria able to produce such chromophore particles in vitro, when cultivated on medium containing prewarmed blood (Chocolate Blood Medium) and to provoke the appearance of that material in normal blood, initially free from it. The vibrational spectra of these micrometer size coloured particles have been recorded by a micro-Raman Spectrometer and the identical nature of the blue particles from the two different sources has been well established. These …findings suggest that the blue particles in pathological blood are originated by bacteria. The circumstances of the discovery of the microbial chromophore materials in blood, particularly but non exclusively in cases of cancer or leukemia can be discussed in comparison with the other pathogenic mechanisms. Show more

DOI: 10.3233/BIR-1984-23S160

Citation: Biorheology, vol. 23, no. s1, pp. S345-S347, 1984