Clinical Hemorheology and Microcirculation - Volume 2, issue 1-2

Authors: Copley, Alfed L. | Witte, Siegfried

Article Type: Editorial

DOI: 10.3233/CH-1982-21-201

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 1-1, 1982

Authors: Oka, Syoten

Article Type: Research Article

Abstract: Out of the various problems in relation to clinical hemorheology, three items have been chosen to give a brief review together with the author’s own work and idea. The first item is the Copley–Scott Blair phenomenon, i.e. the remarkable decrease of apparent viscosity of blood in a fibrin-coated capillary tube as compared with that in a glass tube. A new explanation of this phenomenon is given based on an electric double layer formed at the interface between the wall and blood. The second item is the wall surface effect on clotting of blood. Kaibara and Fukada observed a remarkable difference …between the clotting curves of blood in a glass test tube and that in a siliconized polyethylene tube. They attributed this effect to the difference of disruption of platelets between the glass surface and the siliconized surface. Our idea is that the collision frequency of a platelet with the wall surface will be explained by the total potential energy curve due to the presence of electric double layers. The third item refers to the electrical aspect of intravascular thrombus formation. The author’s idea is that the sticking of platelets to the endothelium and the aggregation of platelets may be explained by the intermembrane potential curve. The role of turbulence in thrombus formation may also be explained along this line of thought. Show more

Keywords: Surface phenomena, clinical hemorheology, Copley–Scott Blair phenomenon, electric double layer, platelets, thrombus formation

DOI: 10.3233/CH-1982-21-202

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 3-6, 1982

Authors: Kaibara, M. | Fukada, E.

Article Type: Research Article

Abstract: The dynamic rigidity modulus G′ and loss modulus G″ of horse and bovine bloods were determined over a wide range of hematocrit at 1 Hz after imposing the steady shear of 66 sec−1 for 1 min. At hematocrits below about 80% the value of G′ for horse blood gradually decreased with time after the initial increase. The rate of decrease of G′ showed maxima at hematocrits around 25 and 55% respectively. At high hematocrits above 80% no time variation of G’ was observed. The values of G′ and G″ for bovine blood were much smaller than those for …horse blood. No time variation of G′ and G″ for bovine blood was observed at any hematocrits. These observations indicate that changes in G′ with time at hematocrits below 50% are mainly due to the formation of rouleaux network in blood and the subsequent formation of the nonhomogeneous assembly of rouleaux like a pattern of islands in sea. At hematocrits between 50 and 80%, the time variation of G′ reflect the change of the aggregation structure of closely packed red blood cells from nonequilibrium state to equilibrium one. At high homatocrits above 80%, G′ mainly reflect the deformability or stiffness of packed red blood cells rather than the interaction between red blood cells. Show more

Keywords: Horse blood, bovine blood, viscoelasticity, dynamic rigidity modulus, loss modulus, hematocrit

DOI: 10.3233/CH-1982-21-203

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 7-11, 1982

Authors: Lingard, P.S.

Article Type: Research Article

Abstract: The circulation is designed for oxygen and carbon dioxide transport by the blood. Red cells collect oxygen in the lungs and carry it to the capillaries of the heart, brain and other tissues where it is metabolised. Physiological studies show that oxygen supply may be blood flow limited, but the role of blood rheology is ill-defined. This report outlines a simple cardiovascular model in which available hemodynamic and rheological data are embodied. Steady state transport optimisation data are calculated for the poorly compensated circulation assuming various ratios between capillary and systemic blood hematocrit. Limitations are defined and capillary perfusion velocity …calculated for cardiac output-modulated flow through a typical bed at constant perfusion pressure. Oxygen tension profiles are predicted using the Krogh cylinder model. Tissue PO2 becomes a function of the systemic hematocrit and the capillary-systemic hematocrit ratio, being almost constant for hematocrits from 10–40% with a potentially lethal fall-off above about 50%. Show more

Keywords: Hemorheo1ogy, red cells, tissue oxygen supply, blood flow, cardiovascular model, hematocrit

DOI: 10.3233/CH-1982-21-204

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 13-19, 1982

Authors: Yamakawa, Takashi | Nuccio, Jill | Chang, Bing-Lo | Bing, Richard J.

Article Type: Research Article

Abstract: By means of transillumination (light pipe and microtransillumination) comparative analyses were carried out in geometry, topography and morphometry of microcirculation between the left atrial muscle and cerebral cortex of the cats using computer analysis. In addition, specific types of capillary distribution (symmetric parallel, symmetric antiparallel and asymmetric distribution) in these two organs was ascertained from images visualized on films. It was found that capillary diameter, intercapillary distance, total capillary length per tissue volume, total capillary surface area per tissue volume, total capillary volume fraction and capillary tortuosity differed significantly between the two organs. The left atrial muscle had a low …degree of capillary tortuosity and both symmetric and asymmetric distributions. The cerebral cortex had a high tortuosity and mostly asymmetric distribution. These parameters were organotypic and related to their roles in tissue oxygen supply. Show more

Keywords: Capillary topography, morphometry, microcirculation, cat heart and brain, intravital microscopy, tissue oxygen supply

DOI: 10.3233/CH-1982-21-205

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 21-30, 1982

Authors: Fukushima, Takayoshi | Azuma, Takehiko

Article Type: Research Article

Abstract: Pulsatile flow in arterial models with an axisymmetric or nonsymmetric stenosis was visualized to investigate the pattern of streamlines and the mode of vortex formation. In a model with an axisymmetric constriction, a decrease in the constriction ratio or a rise in the Reynolds number decreased the magnitude of the acceleration number, which was an index to the unsteadiness of the flow, and facilitated the repetitive shedding of vortex rings which in turn led to the generation of turbulence. The presence of an oscillatory component in flow velocity altered the pattern of steady flow around a non symmetric constriction, which …was characterized by a pair of standing vortices behind and a stationary horseshoe vortex in front of the obstacle. In pulsatile flow, nonsymmetric vortex rings were generated periodically behind the obstacle and shed down-stream in succession, and periodical changes also were observed in the position and width of the horseshoe vortex. Show more

Keywords: Pulsatile flow, arterial models, stenosis, streamline patterns, vortex formation, Reynolds number

DOI: 10.3233/CH-1982-21-206

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 31-41, 1982

Authors: Fukushima, Takayoshi | Matsuzawa, Teruo | Azuma, Takehiko

Article Type: Research Article

Abstract: In order to elucidate performance characteristics of a few prosthetic heart valves, the present in vitro study was carried out to investigate disturbances of flow past the prostheses. Measurements of pressure and velocity around, and visualization of flow across, the valves were made with three kinds of the valves attached to the entrance of a metacrylate model of the aorta. Comparison of the pressure drops caused by these valves with those by plate orifices revealed that the prostheses corresponded to the orifices, the opening area of which was approximately 45% of the cross-sectional area of the inlet section. The pressure …drop by the Björk-Shiley valve was smaller than the drops by the Kay-Suzuki and the SAM-MT valves. Highly turbulent flow taking place downstream of the valves seemed to be responsible for the energy loss induced by the valves. The structure of the turbulence was studied in association with the formation of thrombi and focal vascular lesions. Show more

Keywords: Prosthetic heart valves, fluid mechanics, flow past prosthetics, turbulent flow, thrombus formation, focal vascular lesions

DOI: 10.3233/CH-1982-21-207

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 43-50, 1982

Authors: Hartert, Hellmut H.

Article Type: Research Article

Abstract: Coagulation of blood is comparable to building a house. The plasmatic (fluid) phase of coagulation in the example of building includes any preparation until laying the foundation stone. Thereafter the proper phase of coagulation is the erection of the building itself. Thrombelastography and Resonance-Thrombography are the methods to measure the start and progress in raising a clot structure with elastic fibrin molecules and their condensation by platelets. Their parameter of measurement is clot elasticity, which in a wide range allows to differentiate the course of blood coagulation for diagnosis of hemorrhagic diseases as well as for the effect of clot-controlling …therapeutical and experimental measures. In the Thrombelastogram (TEG) fibrin elasticity and condensating effect of platelets cannot be differentiated, a fact which in a clinical laboratory for screening of hemorrhagic disorders represents some methodical limitation. Therefore the Resonace-Thrombography was developed, which with a simulation of flow. with a permanent “natural” strain on the growing fibrin structure by minimal orbital movement and with the utilization of a resonance effect for high sensitivity in measuring elasticity module is able to give additional informations. Especially platelet dysfunctions, dysfibrinogenemias as in liver diseases and in disseminated intravascular clotting as well as combined defects of the coagulation system including fibrinolysis may in the sense of screening by differentiation early and simply be diagnosed in the Resonance-Thrombogram (RTG). Show more

Keywords: Blood clotting, resonance-thrombography, thrombelastography, clot structure, elastic fibrin molecules, platelets

DOI: 10.3233/CH-1982-21-208

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 51-69, 1982

Authors: Matsuda, Tamotsu

Article Type: Research Article

Abstract: Role of antithrombin III (ATIII) and blood viscosity in development of thrombosis are investigated. A moderate decrease in levels of plasma ATIII before and after the development of acute myocardial infarction was observed. In cases of acute myocardial infarction, in whom concentrations of ATIII in plasma decreased markedly, thromboembolic episodes frequently developed. Levels of ATIII in plasma occasionally increased following oral anticoagulant therapy. From these results, it is suggested that ATIII in blood may be consumed in hypercoagulable states by reacting activated procoagulants formed in circulating blood. In observations in 437 autopsied cases with mean age of 77, acute myocardial …infarction seldom developed when sclerotic changes of coronary arteries remained mild. Incidence of myocardial infarction in cases with severe coronary sclerosis increased with elevation of hematocrits, measured on admission. It is suggested that, in cases of myocardial infarction with slight arteriosclerotic changes or very low hematocrit values, possibility of complication of DIC (disseminated intravascular coagulation) should be considered. Most remarkable decrease in levels of ATIII was observed in cases of DIC. Necessity of replacement therapy of ATIII is suggested, because of inefficacy of heparin therapy in patients with DIC, in whom levels of ATIII markedly decreased. Concentrations of ATIII in plasma were lower in younger females but higher in elderly ones than males with corresponding ages. Blood viscosity and hematocrit values were lower in women than in men in all decades of life over age 20. In elderly women, these may act beneficially for protecting them from thrombosis. Show more

Keywords: Hypercoagulabi1ity, thrombosis, antithrombin III, blood viscosity, acute myocardial infarction, procoagulants

DOI: 10.3233/CH-1982-21-209

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 71-76, 1982

Authors: Shiga, Takeshi | Maeda, Nobuji | Suda, Takeo | Kon, Kazunori | Sekiya, Misuzu

Article Type: Research Article

Abstract: Effects of artificially augmented membrane cholesterol on red cell functions (rheology and oxygen transport) were studied. As increasing the cholesterol content of human red cells by incubation with phospholipid vesicles containing cholesterol, the following dysfunctions were observed. 1) The decreased membrane fluidity as monitored by spin label motion. 2) The decreased deformability, due to hardening of lipid membrane. 3) The increased suspension viscosity, due to decreasing of deformability. 4) The retardation of oxygen release from red cells, inspite of constant oxygen affinity, due to the augmented oxygen diffusion barrier. In addition, the influence of cross-linked membrane proteins on membrane lipids …was de- scribed. The degrees of dysfunctions induced by excess membrane cholesterol were roughly quantified, and the phenomena were explained on the basis of molecular interaction of cholesterol in membrane. Show more

Keywords: Cholesterol, red cell deformability, red cell functions, membrane fluidity, suspension viscosity, xygen release

DOI: 10.3233/CH-1982-21-210

Citation: Clinical Hemorheology and Microcirculation, vol. 2, no. 1-2, pp. 77-83, 1982