Clinical Hemorheology and Microcirculation - Volume 9, issue 5

Article Type: Editorial

DOI: 10.3233/CH-1989-9521

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. I-III, 1989

Authors: Stoltz, J.F.

Article Type: Editorial

DOI: 10.3233/CH-1989-9501

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 693-693, 1989

Authors: Janzen, Johan | Brooks, Donald E.

Article Type: Research Article

Abstract: The weak aggregation of red cells, referred to as rouleaux formation, has been explained by the non-specific adsorption of plasma proteins to these cells in a bridging configuration. However, no unequivocal measurement of sufficient protein adsorption to cause aggregation has been reported. Aggregation induced by a depletion mechanism which requires no protein adsorption is also possible. No definitive information is currently available which proves either model but we find little support for the bridging hypothesis in either our own work or in that of others.

Keywords: erythrocyte, rouleaux, fibrinogen, albumin, adsorption, depletion

DOI: 10.3233/CH-1989-9502

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 695-714, 1989

Authors: Donner, M. | Mills, P. | Stoltz, J.F.

Article Type: Research Article

Abstract: This paper deals with the effect of albumin and immunoglobulins on erythrocyte aggregation parameters. The study was carried out with an automatic system based on the light reflectometry technique which allows to determine kinetic parameters and dissociation shear rates. The plasma substitution by physiological solution or albumin showed the role of albumin on dissociation shear rates. Albumin properties were altered by heating at 56–60°C. In presence of immunoglobulins, the role of albumin appeared to be complex, depending on the Alb/Glo ratio.

Keywords: Erythrocyte aggregation, Albumin, Immunoglobulins

DOI: 10.3233/CH-1989-9503

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 715-721, 1989

Authors: Sowemimo-Coker, S.O. | Whittingstall, P. | Pietsch, L. | Bauersachs, R.M. | Wenby, R.B. | Meiselman, H.J.

Article Type: Research Article

Abstract: The present study was designed to extend our prior observations of RBC aggregation (Clinical Hemorheology 7, 93–108, 1987) in order to examine the electrokinetic behavior of age-separated RBC in various media, aggregation behavior of rat and bovine RBC in plasma, dextran and PVP, and donor-specific differences in human RBC aggregation. Our results indicate: 1) age-separated human RBC exhibit identical mobilities in PBS or in albumin, whereas older RBC have significantly (p<0.02) greater mobilities than younger cells in plasma or serum; 2) extracellular calcium reduces equally the mobility of young and old human RBC and increases equally the aggregation of both …cell populations; 3) markedly reduced aggregation for unfractionated rat RBC in dextran T70, greater aggregation for old rat RBC in T70 yet a more negative mobility for these old cells, and no aggregation for bovine RBC in plasma, dextran (T70, T500, T2000) or PVP-360. Of particular interest were donor-specific differences for thrice-washed human RBC suspended in dextran T70; 1) cells exhibit a > two-fold range of aggregation between donors unrelated to ABO blood group or cell volume; 2) significant (p<0.05) correlations were observed between RBC aggregation behavior in autologous plasma and T70, thus suggesting possible in vivo conditioning of the cells. In overview, our current results further emphasize the importance of erythrocyte factors in RBC aggregation and suggest that when evaluating situations associated with abnormal aggregation, possible contributions of cellular as well as suspending media factors need to be considered. Show more

Keywords: RBC aggregation, cell age, calcium, dextran, plasma, erythrocyte properties

DOI: 10.3233/CH-1989-9504

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 723-737, 1989

Authors: Pignon, B. | Muller, S. | Jolly, D. | Siadat, M. | Petitfrere, E. | Vessel, B. | Donner, M. | Potron, G. | Stoltz, J.F.

Article Type: Research Article

Abstract: A biological evaluation of the erythroaggregameter commercialized by SEFAM (Nancy, France) is reported. The main characteristics of the apparatus are: Couette-type viscometer, laser light source (wavelength near infra-red), analysis of back-scattered light Several quantitative parameters are calculated: aggregation times, partial and total dissociation thresholds. Reproductibility and variance are satisfactory. The method is very dependent on the experimental conditions such as: delay between sampling to measurement, temperature, nature of anticoagulant. We confirm the importance of both hematocrit and fibrinogen. There is a sex related difference of aggregation parameters which is not dependent on hematocrit. At last, we have found that erythroaggregameter …was able to detect RBC damages induced by either moderate heating or surface charge alterations. Show more

Keywords: Hemorheology, erythrocyte aggregation, light back-scattering

DOI: 10.3233/CH-1989-9505

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 739-749, 1989

Authors: Teitel, P.

Article Type: Research Article

Abstract: 1. The process of red blood cell (RBC) aggregation is always associated with its counterpart: phase separation. The possibility of predicting the occurrence of a specific hemodynamic effect produced by these two processes in the living vasculature is frequently limited by insufficient information on the extremely complex set of local flow conditions. 2. Polymicroviscometry (PMV) is a microrheological method which obviates the effects of phase separation by analyzing the flow behavior of closely packed RBC (Hct 0.80) through relatively thick (200–400 µm) porous media of non-restrictive geometry. 2/a. In presence of aggregating macromolecules, PMV discloses immediately the …consequences of abnormal interactions between individual RBC, such as typically occurring in “compaction stasis” following from the “reversal of the Fahraeus effect” (Schmid-Schönbein). These are not correlating with the conventionally assessed values of RBC sedimentation rate (ESR). 2/b. PMV results obtained in the absence of aggregating macromolecules depend on the RBC ability to perform the movement of membrane tanktreading and correlate with the RBC life span in the circulation and with the extent of their splenic sequestration. 3. The rheological consequence of an abnormal RBC “deformability” is basically opposed to that of an abnormal propensity of RBC to aggregate. The overall microrheological manifestation of the association of both abnormalities can directly be assessed by PMV; the method might, therefore, be of interest for in vitro and/or extra-vivum pharmacological studies. The process of red blood cell (RBC) aggregation is always associated with its counterpart: phase separation. The possibility of predicting the occurrence of a specific hemodynamic effect produced by these two processes in the living vasculature is frequently limited by insufficient information on the extremely complex set of local flow conditions. Polymicroviscometry (PMV) is a microrheological method which obviates the effects of phase separation by analyzing the flow behavior of closely packed RBC (Hct 0.80) through relatively thick (200–400 µm) porous media of non-restrictive geometry. In presence of aggregating macromolecules, PMV discloses immediately the consequences of abnormal interactions between individual RBC, such as typically occurring in “compaction stasis” following from the “reversal of the Fahraeus effect” (Schmid-Schönbein). These are not correlating with the conventionally assessed values of RBC sedimentation rate (ESR). PMV results obtained in the absence of aggregating macromolecules depend on the RBC ability to perform the movement of membrane tanktreading and correlate with the RBC life span in the circulation and with the extent of their splenic sequestration. The rheological consequence of an abnormal RBC “deformability” is basically opposed to that of an abnormal propensity of RBC to aggregate. The overall microrheological manifestation of the association of both abnormalities can directly be assessed by PMV; the method might, therefore, be of interest for in vitro and/or extra-vivum pharmacological studies. Show more

Keywords: phase separation, yield stress, gravitational sedimentation, compaction stasis, rheological occlusion, red cell membrane tanktreading

DOI: 10.3233/CH-1989-9506

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 751-770, 1989

Authors: Boynard, M. | LeLievre, J.C.

Article Type: Research Article

Abstract: The aggregation phenomenon is an important hemorheological factor which influences blood flow in human capillary bed. Aggregation can be evaluated by a number of methods but none of them can be applied simply to in vivo measurements. In contrast, use of ultrasound waves could allow measurements of mechanical and structural properties of red blood cell (RBC) suspensions as well in vitro as in vivo. To characterize more precisely and quantitatively the aggregation phenomenon, an ultrasonic method based on quantitative echography is used. The aim of this paper is to present effects of some parameters (hematocrit, dextran concentration. RBC electrical charge, …shear stress) on RBC aggregation studied by ultrasonic echography. Sickle cell aggregation is also considered. Show more

Keywords: Aggregation, Red Blood Cell, Ultrasound Backscattering

DOI: 10.3233/CH-1989-9507

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 771-779, 1989

Authors: Quemada, Daniel

Article Type: Research Article

Abstract: Linking between blood viscosity and erythrocyte aggregation is interpreted as resulting of structural changes of red blood cell aggregates and their clusters, in the absence of blood flow. Limits of applying such an interpretation is discussed with the help of few examples.

Keywords: Erythrocyte aggregation, blood viscosity

DOI: 10.3233/CH-1989-9508

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 781-790, 1989

Authors: McMillan, Donald E.

Article Type: Research Article

Abstract: Because blood is a non-Newtonian fluid, its energy dissipation during flow is more complex than that of Newtonian fluids. We have shown that, when flow is reinitiated after a pause comparable to physiologic diastole, that a substantial extra transient shear stress develops. This briefly increased resistance is related in shape and duration to blood thixotropy. Both are linked through their dependence on total shear strain (shear rate × time) and its associated rapidly increasing orthogonal reflectivity to the development of cell orientation as flow is initiated and restored. Studies of blood from diabetic patients suggest that a greater predisposition to …aggregation of red blood cells mediated by fibrinogen and other plasma proteins influences the magnitude of this transient resistance. The timing and magnitude of blood’s transient resistance are such that, combined with blood’s shear-thinning, it burdens cardiac systole in the large arteries by an increase as great as ten percent and with a brief local peak excess of more than a third. Show more

Keywords: diabetes mellitus, transient resistance, thixotropy, cell orientation

DOI: 10.3233/CH-1989-9509

Citation: Clinical Hemorheology and Microcirculation, vol. 9, no. 5, pp. 791-796, 1989