ISSN:
1432-2013
Keywords:
Red Cell Aggregation
;
Rouleaux
;
Photometry of Blood
;
Viscometry of Blood
;
High Molecular Weight Dextrans
;
Low Molecular Weight Dextrans
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Employing both microscopic and photometric methods the rheology of pathological red cell aggregation was studied in model experiments. Suspensions of washed human red blood cells in dextran solutions containing rising concentrations of dextrans (M.W. 40000, 70000, 110000, 250000, 500000) were used. At low concentrations (〈500 mg-%) of high molecular weight dextrans (〉70000)red cell suspensions formed aggregates similar to the ones found in normal human blood. At higher concentrations, the aggregates were similar to those observed in pathological human blood. The aggregates were studied under the condition of stasis, slow flow and at shear rate of their hydrodynamic dispersion. Besides, the flow behavior of the dispersed cells at high shear rates was studied. We found: 1. In all samples the rate of spontaneous aggregate re-formation in stasis (following hydrodynamic desaggregation) rose with rising dextran concentration up to 5.0 g-%. 2. The shear resistance of the aggregates, as measured by the shear stress necessary to keep them dispersed, rose up to concentrations of 2.5 g-%, but fell at higher concentrations. 3. Only with dextran of a molecular weight above 110000 coarse agglomerates could be produced at high concentrations. Loose elastic meshes were rapidly produced at high concentrations of Dx 70. 4. When subjected to steady state low shear (7 sec−1) only the agglomerates, but not the meshes rapidly grew in size. Most of the aggregation kinetics recorded by photometry and microscopy evaded detection by viscometry.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00587850
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