Biorheology - Volume 27, issue 6

Article Type: Editorial

DOI: 10.3233/BIR-1990-27618

Citation: Biorheology, vol. 27, no. 6, pp. I-III, 1990

Authors: Silberberg, Alex | Copley, Alfred L.

Article Type: Editorial

DOI: 10.3233/BIR-1990-27601

Citation: Biorheology, vol. 27, no. 6, pp. 813-813, 1990

Authors: Silberberg, Alex | Copley, Alfred L.

Article Type: Obituary

DOI: 10.3233/BIR-1990-27602

Citation: Biorheology, vol. 27, no. 6, pp. 815-816, 1990

Authors: Hochmuth, R.M. | Needham, D.

Article Type: Research Article

Abstract: Passive neutrophils from five different individuals are rapidly aspirated at constant suction pressure and at room temperature into a pipet with a diameter of 4 μ m. The excess suction pressures (i.e., the pressures in excess of the small threshold pressure required to produce continuous flow into the pipet) are 5000, 10000 and 20000 dyn/cm2 (0.5, 1 and 2 kPa) and are comparable to those encountered in the microcirculation. The rate of entry into the pipet is modeled with a linearized version of a theory by Yeung and Evans for the newtonian flow of a neutrophil into a pipet …or pore. From this theory and measurements of the cell size and its rate of entry into the pipet, we can calculate a value for the cytoplasmic viscosity. A linear (newtonian) fit of the theory to the experimental data gives a value for the viscosity of 1050 poise. A non-linear fit predicts a decrease in the “apparent viscosity” from about 1500 poise at zero excess pressure to 1000 poise at an excess aspiration pressure of 20,000 dyn/cm2 . Our experiments and analysis also allow us to calculate a value for the transit time through short pores over a wide range of excess aspiration pressures and pore diameters. For example, for a pore diameter of 3 μ m and an aspiration pressure of 1250 dyn/cm2 , we predict a transit time of about 70 s. At 6 μ m and 20,000 dyn/cm2 , the predicted transit time is only about 0.04 s. Show more

Keywords: Neutrophil, viscosity, pipet, pore, transit time

DOI: 10.3233/BIR-1990-27603

Citation: Biorheology, vol. 27, no. 6, pp. 817-828, 1990

Authors: Moessmer, Georg | Meiselman, Herbert J.

Article Type: Research Article

Abstract: Transit times of individual polymorphonuclear leukocytes (PMN) through cylindrical micropores with a diameter of 8 μ m and a length of 19 μ m were measured at pressure gradients of 3 to 10 cm H2 O using the Cell Transit Analyzer (CTA); this system employs a conductometric principle and provides a frequency histogram of transit times for > 1000 cells within 3 to 4 minutes. Salient results included: 1) linear pressure-flow relations (r⩾0.99); 2) mean transit times for PMN on the order of 10-20 milliseconds at a pressure gradient of 4 cm H2 O and thus transit times at least …10-fold longer than for RBC under the same conditions; 3) broad distributions with marked skewness toward longer transit times, indicating a wide range of rheo1ogic properties; 4) increased transit times in either hypotonic or hypertonic media; 5) marked increases of transit times following activation with FMLP; 6) considerable differences between the volume distribution and the transit time distribution of PMN. These results suggest the basic usefulness of the CTA for the analysis of rheologic properties of white blood cells in both normal and pathologic states. Show more

Keywords: micropore filtration, polymorphonuclear leukocytes, transit time, white blood cell rheology, WBC deformability, WBC volume

DOI: 10.3233/BIR-1990-27604

Citation: Biorheology, vol. 27, no. 6, pp. 829-848, 1990

Authors: Elson, E.L. | Pasternak, C. | Liu, Z.-Y. | Young, J.-I. | Schwab III, B. | Worthen, G.S. | Downey, G. | Michaels, R. | McConnaughey, W.B. | McDaniel, M. | Wolf, B. | Zahalak, G.I.

Article Type: Research Article

Abstract: Different kinds of leukocytes undergo cytoskeleton-dependent mechanical responses associated wit their specific physiological functions. We have investigated cellular stiffening of several types of leukocytes using a method which measures the force resisting cellular indentation. We have found that lymphocytes stiffen in response to crosslinking cell surface antigens in a process associated with the much studied capping and patching processes. Further studies of myosin-deficient mutants of the ameba Dictyostelium discoideum suggest that this stiffening process results from a myosin dependent contractile process. Rat basophilic leukemia cells and pancreatic islet cells stiffen when triggered to secrete. The function of these cytoskeleton dependent …processes is now unknown, but, at least in the islet cells, may be related to a regulation of the rate of secretion. Primary neutrophils stiffen in response to the chemotactic agent, fMet-Leu-Phe. This stiffening may be responsible for retention of these cells in the pulmonary microcirculation during response to inflammation. These observations pose the challenge of determining the structural basis, mechanism, and physiological function of each of these cellular responses. Show more

Keywords: Cell Stiffening, Patching, Capping, Secretion, Cytoskeleton, Viscoelasticity

DOI: 10.3233/BIR-1990-27605

Citation: Biorheology, vol. 27, no. 6, pp. 849-858, 1990

Authors: Schmid-Schönbein, Geert W. | Engler, Robert L.

Article Type: Research Article

Abstract: Recent evidence for a role of granulocytes in ischemic organ injury and in hemorrhagic shock is provided. Compared to red cell, granulocytes are large cells and have a stiff cytoplasm, making them prone to entrapment in the microcirculation. After activation, granulocytes become adhesive, they can elaborate superoxide radicals and release proteolytic enzymes. In the circulation a subgroup of granulocytes are in a spontaneously activated state. If during shock such cells become trapped in the microcirculation they impose a risk for organ injury. In a short term shock protocol, the group of surviving and non-surviving animals can be sharply distinguished by …the number of activated granulocytes before shock. Experimental forms of granulocyte activation in the coronary circulation cause temporary trapping of cells, an increase in vascular resistance, and a transient reduction of muscle contraction even in the presence of a normal perfusion pressure. Detection of spontaneous granulocyte activation requires the development of new tests which can be carried out on fresh un separated blood samples. We provide here also a critical evaluation of experimental neutropenia as a test for granulocyte related hypotheses. Show more

Keywords: granulocytes, activation, oxygen free radicals, no-reflow, ischemia, tissue injury

DOI: 10.3233/BIR-1990-27606

Citation: Biorheology, vol. 27, no. 6, pp. 859-869, 1990

Authors: Witte, Siegfried

Article Type: Introduction

DOI: 10.3233/BIR-1990-27607

Citation: Biorheology, vol. 27, no. 6, pp. 871-871, 1990

Authors: Nash, G.B.

Article Type: Research Article

Abstract: It could be claimed that expansion in clinical aspects of haemorheology has largely been fuelled by the development of a simple test of blood flow properties, i.e., analysis of filterability. With time, the level of sophistication in equipment, theory and sample preparation has increased. Theories for the development of flow in the filter have been described and these enable cellular parameters, such as transit times, to be calculated from experimental data. These theories can be quite general, and applied to filtration of red or white cells. Ideally, experimental design requires an understanding of cell behaviour at the filter and of …the effects of factors such as the sample concentration and volume, and the presence of different types of cells or subpopulations. Otherwise, results are susceptible to misinterpretation, particularly if impurities or mixed populations of cells are present. It is thus very important to know accurately the constituents of the test suspension. In clinical applications the trend has been to move away from whole blood filtration, toward use of relatively pure suspension of separated red cells and white cells. In the area of red cell filtration this has led to reappraisal of some previously reported abnormalities. The relatively new study of white cell filtration should benefit from previous experience, but there is the added problem of the reactivity of the cells under test, and their mixed nature. In any case, critical evaluation of the meaning and clinical relevance of results is necessary. Show more

Keywords: Red Blood Cells, White Blood Cells, Filterability

DOI: 10.3233/BIR-1990-27608

Citation: Biorheology, vol. 27, no. 6, pp. 873-882, 1990

Authors: Chmiel, H. | Anadere, I. | Walitza, E.

Article Type: Research Article

Abstract: A brief outline of the background of viscoelasticity of blood is given in order to derive for blood relevant parameters. In this context, especially one method, the sinusoidal oscillating capillary rheometry, is discussed. The determination of different parameters to characterize blood samples, e.g. the viscoelastic phase angle, an aggregation index, a flexibility index, hematocrit and plasma viscosity is described. Most of these parameters show increased values in disease; however they can be influenced by drug treatment.

Keywords: Blood viscoelasticity, oscillating capillary rheometer, aggregation index, flexibility index, viscoelastic phase angle

DOI: 10.3233/BIR-1990-27609

Citation: Biorheology, vol. 27, no. 6, pp. 883-894, 1990

Authors: Schneditz, D. | Moser, M. | Smolle-Jüttner, F.M. | Dörp, E. | Pogglitsch, H. | Kenner, T.

Article Type: Research Article

Abstract: Both blood density and sound speed are closely related to total protein concentration in blood and, as a consequence, to rheologically important parameters of blood. Two methods that permit continuous measurement of these properties, the mechanical oscillator technique and the new ultrasonic technique, were used for measuring blood protein concentration over a continuous period of time in a group of hemodialysis patients and in volunteers. It was seen that the concentration of the components of blood varies considerably. This variability is related to transport phenomena within as well as to the flow of masses across the cardiovascular compartment. From the …continuous measurement of concentrations during hemodialysis treatment, relative changes in blood volume can be recorded in order to control the fluid balance of the patient. Rapid fluctuations at the macroscopic scale with periods of 5 to 30 seconds are due to heterogeneities at the microscopic scale and to the particular rheological behaviour of the red blood cells at the level of the capillaries and the small blood vessels. The amplitude of rapid oscillations increased up to 1.2 % in terms of hematocrit values when there was rhythmic, spontaneous breathing at various frequencies. The measurement of concentrations at an accessible measuring site may be used to investigate the rheology of blood in the human microvasculature. Show more

Keywords: density, sound speed, protein concentration, blood volume, oscillations

DOI: 10.3233/BIR-1990-27610

Citation: Biorheology, vol. 27, no. 6, pp. 895-902, 1990

Authors: Brückner, Uwe B. | Messmer, K.

Article Type: Research Article

Abstract: The interrelationship between systemic oxygen transport and hematocrit, has been studied under various conditions, while the influence of plasma viscosity on oxygen transport and tissue oxygenation has not entirely been explored. In experiments in dogs the plasma viscosity was increased either by isovolemic hemodilution with 6% hydroxyethyl starch (HES) 200/0.62, or 6% dextran-70, or by infusion of dextran-500 in a volume equivalent to 4% of blood volume from baseline to 3 mPa·s. Cardiac output and regional blood flow were assessed by means of radioactive labelled microspheres and local tissue oxygenation by means of pO2 multiwire surface electrodes. …In normotensive heal thy animals elevated plasma viscosity did neither jeopardize systemic nor regional blood flow; local tissue oxygenation of skeletal muscle remained unchanged or was even improved. We conclude that among the rheological factors influencing oxygen transport, the hematocrit plays the predominant role, while plasma viscosity is of minor importance. Show more

Keywords: plasma viscosity, hemodilution, organ blood flow, oxygen transport, dextran-70, dextran-500, hydroxyethyl starch 200/0.62, surface pO2

DOI: 10.3233/BIR-1990-27611

Citation: Biorheology, vol. 27, no. 6, pp. 903-912, 1990

Authors: Wolf, H.R.D. | Witte, S.

Article Type: Research Article

Abstract: Continuously measured oxygen uptake during constant work exercise (15′ 50W) reveals increasing oxygen consumption in individuals with elevated blood viscosity parameters, indicating persistent contribution of anaerobic glycolysis during steady state exercise far below expected “anaerobic threshold”. Improvement of viscosity parameters by prostaglandin E1 infusion (Prostavasin® ) 40 μ g i.v., naftidrofurylhydrogenoxalat (Dusodril® pi) 400 mg i.v. or hemodilution with 500 ml 6% hydroxyethylamylum MW 40000(Onkohaes® ) in 5 patients results in significant reduction of this oxygen gradient in subsequent exercise test. Integrated VO2 during exercise above the mean value at rest or the quotient of VO2 …during 15 min by VO2 during 30 min (including recovery time) are not differing significantly due to high variations inter- and intraindividually. Oxygen gradient during submaximal constant exercise permits direct clinical determination of microcirculatory performance in involved muscle tissue as a function of blood viscosity. Show more

Keywords: Blood viscosity, oxygen uptake, ergometry, microcirculation, muscle perfusion

DOI: 10.3233/BIR-1990-27612

Citation: Biorheology, vol. 27, no. 6, pp. 913-919, 1990

Authors: Hartert, H.

Article Type: Research Article

Abstract: Orbitometry (Hartert) is a rheological ex-vivo method to follow up physical assembly of a coagulum in layers during natural intensity of flow by orbital movement. Fibrin elasticity in the Orbitometers mode of Resonance Thrombography is differentiated from platelet activity as well as e.g. from the effects of disseminated coagulation - minimal in liver disease and maximal during disturbances of delivery. Transition into the mode of dynamic Tendography (Hartert) will e.g. register all fast going tests lasting minutes or seconds. It is comparable to an accelerated form of Thrombelastography (Hartert), the intercourse of which with coagulum yet is an exclusively static …operation. Another category is measurement of blood and plasma viscosity. In concentrated blood it seizes plasticity of blood cells as well as their intensity of aggregation in orbital flow. The latest methodical development of Orbitometry is control of platelet activity in its function of adhesion. This is realized by measurement of specific physical effects released in platelet containing coagulum. They generate a structural degradation of fibrin elasticity modul as well as a tendency for coagulum adhesion. The practical use of Adhesiography is control of anticoagulants and platelet protecting substances in their quantitative influence on coagulum structure and on the mentioned platelet activities. A special disturbance of these platelet depending mechanisms obviously is getting evidence in case of v.Willebrand’ s syndrome. Show more

Keywords: Orbitometer, fibrin elasticity, strain of flow, resonance, adhesiography, platelet shape change

DOI: 10.3233/BIR-1990-27613

Citation: Biorheology, vol. 27, no. 6, pp. 921-929, 1990

Article Type: Abstract

DOI: 10.3233/BIR-1990-27614

Citation: Biorheology, vol. 27, no. 6, pp. 931-961, 1990

Authors: Singh, Megha | Lucas, C.L. | Henry, G.W. | Ferreiro, J.I. | Wilcox, B.R.

Article Type: Short Communication

Keywords: Multiangle, Bifurcation, Steady flow, Reattachment point

DOI: 10.3233/BIR-1990-27615

Citation: Biorheology, vol. 27, no. 6, pp. 963-970, 1990

Authors: Pralhad, R.N.

Article Type: Letter

Abstract: Some errors have been observed in the analytical expression for the resistance to flow (λ R ), and in the computation of shear stress distribution (τ R ) in the analysis of Prawal Sinha and Chandan Singh (1). These errors have been rectified in the present analysis. Also, better values have been suggested for the couple stress parameter α ¯ for getting better results for λ R and τ R .

Keywords: Blood flow, Stenosis, Couple stress fluid, Hemodynamics

DOI: 10.3233/BIR-1990-27616

Citation: Biorheology, vol. 27, no. 6, pp. 971-974, 1990

Article Type: Other

DOI: 10.3233/BIR-1990-27617

Citation: Biorheology, vol. 27, no. 6, pp. 975-975, 1990