Clinical Hemorheology and Microcirculation - Volume 1, issue 4

Article Type: Editorial

DOI: 10.3233/CH-1981-1401

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 333-334, 1981

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

Article Type: Research Article

Abstract: It has always been assumed that blood viscosity at high shear rates is largely determined by red cell deformability (RCD). However the literature reporting a direct correlation between the measurements of blood viscosity and RCD is scarce. Experiments were carried out to establish the relationship between red cell filterability (RCF) and various viscosity measurements. RCF correlated best with the Δ η (difference in viscosity measurements at shear rates 2.37 and 94.5s−1 ) of concentrated, washed red cells.

Keywords: red cell deformability, red cell filterability, blood viscosity, red cells, red cell aggregation

DOI: 10.3233/CH-1981-1402

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 335-340, 1981

Authors: Stäubli, M. | Schläppi, P. | Straub, P.W.

Article Type: Research Article

Abstract: The filterability of concentrated red cell suspensions as assayed with filter paper is considered to be a measure of the suspension viscosity. In order to investigate how filterability is related to viscosity as determined in a cone and plate rotational viscometer we have studied suspensions of normal and artificially altered red cells with both methods. For shear rates between 11 and 230 sec−1 a positive correlation was found between apparent viscosity and index of filterability. The correlation was better the higher the shear rates used in viscometry. At high shear rates the common critical variable appears to be …red cell deformability. The lower the shear rate, cell-cell-interactions and other factors become more important. Such factors may be of particular significance for red cell behaviour in the microcirculation of which the filter paper represents a possible model. Show more

Keywords: Erythrocytes, filterability, viscosity, paper filter

DOI: 10.3233/CH-1981-1403

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 341-347, 1981

Authors: Rebhorn, H. | Anadere, I. | Chmiel, H.

Article Type: Research Article

Abstract: Several hemorheological parameters of whole blood and plasma from healthy donors and from patients with multiple myeloma or Morbus Waldenström were investigated. The values of both mean hematocrit and viscoelastic parameters of whole blood were significantly lower and the plasma viscosities were higher in the patients than those of the control group. On the contrary, the calculated viscoelasticity data from a standard hematocrit of 45 % showed the opposite effect for whole blood. This may suggest, that in the case of non-existing reduced hematocrit values, multiple myeloma patients could exhibit blood hyperviscosity. Further, the determination of “aggregation independent” hematocrit values …for both groups indicated an increased aggregation tendency of erythrocytes in patients with multiple myeloma. Thus the determination of viscoelastic parameters can lead to a better understanding of the hemorheological risk states of the patients and can provide a further aid in the application of drugs. Show more

Keywords: Blood viscoelasticity, plasma viscosity, multiple myeloma, M. Waldenström

DOI: 10.3233/CH-1981-1404

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 349-360, 1981

Authors: McMillan, Donald E. | Utterback, Nyle G.

Article Type: Research Article

Abstract: This study has compared blood adjusted to 41% hematocrit from 10 insulin-requiring diabetic and 10 nondiabetic subjects matched for age and sex. The relationship between increased low shear rate viscosity in diabetes and blood’s viscoelastic and thixotropic behavior was examined. Increased viscosity in the shear rate range from 0.1 to 1 inverse seconds was again demonstrated. Time-based studies carried out at .024 inverse seconds shear rate with a shearing duration of 20, 60, and 200 seconds showed a distinctly different pattern in diabetes; shear stress developed more rapidly and then fell to a lower level than for nondiabetic blood. The …overall response demonstrated that disparities between diabetic and nondiabetic blood were a function of both shearing duration and the time between blood mixing and the initiation of flow. The 20 second patterns were used to estimate the elastic moduli of onset and relaxation. Both moduli were found to be mildly increased in diabetes. Studies in which shearing was repeated after 20 or 50 second nonshearing periods were carried out at 0.27 and 0.66 inverse second shear rates. During the first shearing period the thixotropic component of diabetic blood’s shear stress onset was far more striking than that of nondiabetic blood. During the second shearing period thixotropic behavior and shear stress were both reduced. The difference was particularly noticeable when the shear rate was higher and the duration of flow longer. The observed viscosity of diabetic blood in the shear rate range between 0.1 and 1 inverse seconds is found to be strongly influenced by the length of time from onset of flow. This is due to a substantial increase in the thixotropy of diabetic blood combined with a marginal increase in its elastic resistance. The thixotropic work required to initiate low shear rate flow of diabetic blood is estimated to be more than 30% greater than that for nondiabetic blood. Show more

Keywords: Blood viscosity, diabetes mellitus, thixotropy, viscoelasticity, erythrocyte deformability

DOI: 10.3233/CH-1981-1405

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 361-372, 1981

Authors: Rand, Peter W. | Norton, James M. | Barker, Nancy D. | Richards, Audrey L. | Lacombe, Eleanor H. | Pirone, Louis A.

Article Type: Research Article

Abstract: To investigate the possibility that altered red cell characteristics contribute to the development of diabetic vascular complications, hematologic, rheo1ogic and oxygen transport variables were measured in 42 juvenile-onset and maturity-onset diabetics, and in 36 age- and sex-matched controls. Viscosity measurements were performed on plasma, whole blood and washed red cell suspensions, and the filtration rate of dilute erythrocyte suspensions through 3µ pores was timed. Hemoglobin-oxygen affinity, glycosy1ated hemoglobin, 2,3-diphosphog1ycerate and carboxyhemoglobin were also measured. In comparison to controls, all diabetics as a group demonstrated slightly lower mean cell volume, slightly higher whole blood viscosity and increasingly higher levels of red cell …suspension viscosity at decreasing shear rates. Red cell filtration values were similar between diabetics and controls who did not smoke but were elevated in the smoking controls, and further increased in the smoking diabetics. P50(7.4) values were 1 mm Hg lower than control values in both the juvenile-onset and adult-onset non-smoking diabetics. No correlations between any of these variables and the presence of vascular disease were apparent. Some thoughts regarding the mechanisms of these findings are offered. Show more

Keywords: Red cell filtration, blood viscosity, erythrocyte oxygen transport, diabetes mellitus, smoking

DOI: 10.3233/CH-1981-1406

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 373-384, 1981

Article Type: Abstract

DOI: 10.3233/CH-1981-1407

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 385-389, 1981

Article Type: Abstract

DOI: 10.3233/CH-1981-1408

Citation: Clinical Hemorheology and Microcirculation, vol. 1, no. 4, pp. 391-400, 1981