Clinical Hemorheology and Microcirculation - Volume 3, issue 4

Authors: Papenfuss, Heinz-Dieter | Gross, Joseph F.

Article Type: Research Article

Abstract: A theoretical investigation of ultrafiltration through hollow fibers used in artificial kidney applications is presented. The mass transfer through the semipermeable membranes is based on Starling’s hypothesis. The rheological problem is treated by regarding the blood as a multiple-structured fluid consisting of a Casson fluid and a surrounding cell-free plasma layer. The present model takes into account the effect of concentration polarization of plasma proteins at the fiber walls. In addition to the implicit character of the viscosity law, a difficulty arises from the fact that the viscosity of the blood plasma, which depends on the local plasma protein concentration, …varies along the axis of the fiber and is not known a priori. The numerical solution of the theoretical model yields the total filtration rate as well as local quantities like the transmembrane fluid velocity and the protein concentration as functions of the fiber characteristics and transmembrane pressure drop. A particular application of the present model is the simulation of hemodilution and its effect on the ultrafiltration efficiency of the hollow fibers. Show more

Keywords: hemofiltration, hemorheology, artificial kidney, non-Newtonian fluid, permeability, hemodynamic model

DOI: 10.3233/CH-1983-3401

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 349-365, 1983

Authors: Freitas, J. | Braz-Nogueira, J. | Nogueira da Costa, J. | Martins e Silva, J.

Article Type: Research Article

Abstract: Twenty one ambulatory patients with essential hypertension (10 men, 11 women), 50.6±10.5 years old, had blood pressures of 167.5±17.l mmHg systolic and 106.2±9.9 mmHg diastolic. Most of the patients were under treatment and target organ involvement was not significant. The following parameters were measured on a sample of venous blood: haemoglobin, haematocrit, P50 standard, carboxyemoglobin, red cell 2,3-diphosphoglycerate and blood filterability rate. The hypertensives were significantly different from a group of controls, in having an increase in 2,3-DPG (hypertensives, 18,5±3.32 µmoles/gHb; controls 12.01±1.32 µmoles/gHb; p < 0.01) and a lower filterability rate (11.41±1.31 µl.sec−1 for hypertensives, 15.49±1.65 µl.sec−l …for controls, p < 0.01). The results suggest an increased rigidity of the blood cells which may have consequence on microcirculation and oxygen delivery to tissues. However, no significant difference in P50 standard was observed between hypertensives and controls. Show more

Keywords: blood filterability, red cell 2,3-diphosphoglycerate, P50 standard, human arterial hypertension

DOI: 10.3233/CH-1983-3402

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 367-373, 1983

Authors: Kikuchi, Yuji | Koyama, Tomiyasu

Article Type: Research Article

Abstract: Passability of rabbit red cells through micropores (5 and 3 µm in diameter) was markedly reduced by two weeks of cholesterol feeding. In vitamin E-nicotinate administered rabbits, the pore passage times of red cells became shorter in spite of the cholesterol feeding, suggesting a positive effect of vitamin E-nicotinate on the red cell deformability impaired by hypercholesterolemia. Vitamin E-nicotinate probably modifies the interaction between red cells and plasma cholesterol.

Keywords: cholesterol, vitamin E, red cell deformability

DOI: 10.3233/CH-1983-3403

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 375-382, 1983

Authors: Hanss, M. | Attali, J.R. | Helou, C. | Lemarie, J.C.

Article Type: Research Article

Abstract: A large scale study of the erythrocyte deformability in diabetes is presented. The initial filtration flow rate method is used on diluted (white blood cells reduced) RBC suspensions. The rigidity index thus obtained, IR, is largely insensitive to the filter plugging. A significant increase of IR is observed for diabetic patients (p < 0.001). This difference is probably (p < 0.05) higher for insulin dependent diabetes than for non insulin diabetes patients. A low significance (p < 0.05) negative correlation between IR and the patient’s hematocrit has been observed. No correlation has been found between the RBC rigidity increase and …the following parameters: – plasma glucose, insulin, triglycerides and cholesterol. – glycosylated hemoglobin (HbA1c), MVC, CCMH and WBC count. – presence of microangiopathic complications. plasma glucose, insulin, triglycerides and cholesterol. glycosylated hemoglobin (HbA1c), MVC, CCMH and WBC count. presence of microangiopathic complications. Show more

Keywords: RBC deformability, diabetes, insulin, hematocrit, glycosylated hemoglobin, microangiopathic complications

DOI: 10.3233/CH-1983-3404

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 383-391, 1983

Authors: Neumann, F.J. | Wilgalis, M. | Teitel, P.

Article Type: Research Article

Abstract: In order to estimate the reliability and validity of PMV the rheological behaviour of packed RBC suspensions ascertained by PMV was correlated to the shear stress - shear rate relationship measured by rotational viscometry. The filtrometer as developed by TEITEL & Mussler was used. 10 samples of normal RBC and 10 samples of RBC altered by hypertonicity or diarnide treatment were examined in all of four channels of the filtrometer. Viscometry was performed in the DEER-rheometer. Above a shear stress of about 1 Pa PMV was found to be an appropriate tool to assess the viscous behaviour of RBC suspensions: …correlation coefficients between FPR and apparent fluidity varied from 0.92 to 0.95 and the variation coefficient ranged around 10%. Below 15% of the full range of pressures analyzed (p=38 Pa) PMV does not significantly reflect the apparent viscosity of the sample, and the variation coefficient is high (>20%). Show more

Keywords: Deformability, filtration, fluidity, red blood cells, viscometry

DOI: 10.3233/CH-1983-3405

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 393-407, 1983

Authors: Tillmann, W. | Schröter, W.

Article Type: Review Article

Abstract: The flexibility of human erythrocytes is caused by three properties: membrane flexibility, fluidity of the interior of the cells and a surplus of cell surface area versus cell volume due to the biconcave form. These factors permit them to assume any desired shape without changing their volume. If the fluidity of the cell interior or the surplus of cell surface is reduced, the “conformation instability” of the erythrocyte will decrease. In this overview the connection between rigidity and accelerated destruction of the erythrocytes in congenital hemolytic anemias will be discussed. Although alterations of rheological properties of the erythrocytes are due …to different reasons, the mechanism of hemolysis is identical in nearly all congenital hemolytic anemias. The rigid cells are sequestered in the spleen, because of their inability to pass the small slits between the adventitial cells of the venous sinuses. After splenectomy the survival time of erythrocytes increases because the rigid cells no longer are sequestered at the same rate by the rest of the reticuloendothelial system. Show more

Keywords: deformability, erythrocytes, splenectomy, hemolytic anemias

DOI: 10.3233/CH-1983-3406

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 409-428, 1983

Article Type: Correction

DOI: 10.3233/CH-1983-3407

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 429-429, 1983

Authors: Benner, Klaus-U.

Article Type: Abstract

DOI: 10.3233/CH-1983-3408

Citation: Clinical Hemorheology and Microcirculation, vol. 3, no. 4, pp. 430-432, 1983