Clinical Hemorheology and Microcirculation - Volume 8, issue 2

Authors: Bilto, Y.Y. | Player, M. | Stuart, J.

Article Type: Research Article

Abstract: Erythrocytes from healthy adults and patients with homozygous sickle cell anaemia were treated in vitro with either the calcium ionophore A23187, the K+ ionophore valinomycin, or the Na+ /K+ ionophore nystatin to induce loss of intracellular K+ and water. The dehydrated cells showed loss of filterability (deformability) through pores of 5 µm diameter. Xanthine derivatives possessing one or two long side chains (oxpentifylline, torbafylline [HWA 448] and A81 3138) showed a similar protective effect against loss of filterability at concentrations of 1, 10 and 100 µmol/l and 5 mmol/l. Theophylline (1,3-dimethylxanthine) showed no protective effect at 5 …mmol/l. The presence of at least one long side chain on the xanthine moiety seems to be an important determinant of rheological activity, possibly by increasing binding to the erythrocyte membrane. Show more

Keywords: Rheology, Erythrocyte deformability, Ion transport

DOI: 10.3233/CH-1988-8210

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 211-219, 1988

Authors: Sowter, M.C. | Green, M.A. | Keidan, A.J. | Johnson, C.S. | Stuart, J.

Article Type: Research Article

Abstract: Rheological methods have considerable potential for the study of sickle cell disease. We have developed a 5 µm pore filtration technique to detect the loss of deformability of sickle cells that occurs secondary to polymerization of haemoglobin S. Loss of filterability was shown to be sensitive to enhancement of polymerization caused by rise in temperature, fall in pH, increase in haemoglobin concentration secondary to cell dehydration, and decrease in oxygen tension. Initial-flow-rate filtration of sickle cells through pores of 5 µm diameter can therefore be used to study the pathogenesis of vaso-occlusive events in sickle-cell patients, to screen potential anti-sickling …drugs in vitro, and to monitor the efficacy of such drugs in clinical trials. Show more

Keywords: Rheology, Erythrocyte deformability, Sickle cell anemia

DOI: 10.3233/CH-1988-8211

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 221-234, 1988

Authors: Dintenfass, L.

Article Type: Research Article

Abstract: Excessive aggregation of red cells is a feature of many cardiovascular disorders. Erythrocyte sedimentation rates (corrected for plasma viscosity and haematocrit) show values from 100 to 1,000 mm/hr, but do not distinguish between different morphologies of red cell aggregation. It is unlikely that rouleaux-based aggregation presents a risk factor unless an excessive aggregation leads to a large increase of the low-shear-rate blood viscosity and/or to a high yield point. (Assuming that electrical currents through the blood circulation route are important, an excessive rouleaux network formation will greatly increase resistance in such electrical conduits). A risk factor is presented by …very large and compact aggregates of red cells; in vitro studies using slit-capillary photoviscometer such clumps contained up to 50,000 red cells in a single clump; could occupy a volume of up to 5 million cubic microns (um), and could occlude a circular vessel of up to 100 micron (um) diameter. The mechanism based on the “inversion phenomenon” explains the role of single rigid red cells or smaller rigid aggregates of red cells or platelets, in the sudden increase of resistance to flow. All parts of the cardiovascular system are susceptible to microocclusions, micro-infarctions and micro-gangrene. Specifically this is of importance in the ischaemic heart disease and in diabetes; in prethrombotic states; in many forms of cancer and peripheral vascular disease; in retinopathy and cerebrovascular insufficiency, etc. Show more

Keywords: rouleaux, compact clumps of red cells, risk factors, ischaemic heart disease, myocardial infarction, inversicn phenomenon, slit-capillary-photo-viscometer, microocclusions, rheologic pseudo-spasm

DOI: 10.3233/CH-1988-8212

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 235-255, 1988

Authors: Larsson, Hans | Valdemarsson, Stig | Hedner, Pavo | Odeberg, Håkan

Article Type: Research Article

Abstract: Blood viscosity was measured in 16 hyperthyroid patients before and after normalization of thyroid function, at natural hematocrit (8 patients) and with the hematocrit of the samples adjusted to 40 and/or 45%. In 10 of the patients the passage time for erythrocytes through a cellulose-sigmacell column was also measured. With the hematocrit adjusted to 45% a higher (p < 0.01) blood viscosity was recorded for patients compared to 33 controls at shear rates 0.8 s−1 –40 s−1 . After treatment it decreased (p < 0.05) to a level close to that of controls. Also blood viscosity at hematocrit 40% …decreased upon treatment for hyperthyroidism. The plasma viscosity in the patients did not differ significantly from controls and did not change significantly after treatment for hyperthyroidism. The column passage time was longer for erythrocytes from hyperthyroid patients than controls, and was correlated (p < 0.01) to blood viscosity at hematocrit 45% at all shear rates investigated (r=0.61–0.72). The hematocrit increased from 38.9±3.8 (SD) to 42.1±3.3 % (p < 0.01) after treatment for hyperthyroidism. It is concluded that in hyperthyroidism the erythrocytes may be decreased in concentration and changed in a way that impairs their rheological properties. A normalization is seen upon treatment of the disease. Show more

Keywords: Blood viscosity, hyperthyroidism

DOI: 10.3233/CH-1988-8213

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 257-265, 1988

Authors: Wang, Bao-ping | Sun, Fang-cheng

Article Type: Brief Report

Keywords: Cerebral stroke, Hemodilution, Blood viscosity

DOI: 10.3233/CH-1988-8214

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 267-270, 1988

Authors: Lerche, D.

Article Type: Book Review

DOI: 10.3233/CH-1988-8215

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 271-272, 1988

Authors: Ernst, E.

Article Type: Other

DOI: 10.3233/CH-1988-8216

Citation: Clinical Hemorheology and Microcirculation, vol. 8, no. 2, pp. 273-278, 1988