Analysis of erythrocyte aggregation mechanism in presence of dextran and magnetic field by ultrasound scattering in blood.
TL;DR: The results show that the application of IMF influences the aggregation and sedimentation of erythrocytes and the aggregates thus formed sediment faster than that of control sample.
About: This article is published in Biorheology.The article was published on 1989-01-01. It has received 4 citations till now. The article focuses on the topics: Dextran 70 & Erythrocyte aggregation.
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TL;DR: The significant changes in erythrocyte aggregation and deformability, in comparison with that of control subjects show the relevance of these measurements, which are further supported by in vivo observations of blood flow through microvessels.
Abstract: Diabetes mellitus (DM) is a metabolic disorder characterized by varying or persistent hyperglycemia either due to insufficient production of insulin by pancreas or improper utilization of the glucose. Erythrocytes remain in hyperglycemic environment throughout their life span and thus are subjected to series of compositional changes, which in turn affect their flow properties through alteration of deformation at individual level and aggregation at collective level. This brief review summarizes the changes in biochemical parameters primarily contributing to the erythrocyte deformability and aggregation as measured by various techniques, of blood samples obtained from diabetic subjects. The significant changes in erythrocyte aggregation and deformability, in comparison with that of control subjects show the relevance of these measurements. These changes are further supported by in vivo observations of blood flow through microvessels. Finally the relevance of these in combination with other clinical parameters is suggested.
100 citations
TL;DR: An experimental validation of the Structure Factor Size Estimator (SFSE), a non-Rayleigh scattering model adapted for dense suspensions, was performed on 4 erythrocyte preparations with different aggregation tendencies, finding that a "normal" aggregability promoted the formation of concentric rings with varying viscosities.
37 citations
Cites background from "Analysis of erythrocyte aggregation..."
...This behavior for fluid-like deformable corpuscles seems improbable based on earlier reports [55]: erythrocytes are rather concentrated near the center axis in that particular report....
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TL;DR: An analytical model describing its variation versus time, for human aggregated red blood cells in sedimentation, is proposed and knowledge of the durations t/ sub s/, t/sub f/ and the maximum slope s of the curve during the intermediate phase, determined with the model, allows a means to study RBC aggregate growth.
Abstract: Ultrasound backscattering is well adapted to study the red blood cell (RBC) aggregation phenomenon and growth of RBC aggregates since the backscattered ultrasonic intensity depends on the sixth power of the mean radius of the scattering centers when considered as spherical. Thus, small variations of aggregate size induce large variations of the backscattered intensity. From measurements of the ultrasonic backscattering coefficient (ultrasonic backscattering cross section per unit volume of suspension), an analytical model describing its variation versus time, for human aggregated red blood cells in sedimentation, is proposed. Results given by the model allow to define three phases in the phenomenon: 1) a starting phase characterized by a duration t/sub s/; 2) a stationary final phase beginning at time t/sub f/; 3) a growing intermediate phase characterized by its duration t/sub f/-t/sub s/. The analytical model has been applied to describe RBC aggregation in dextran 70,000 dalton of different concentrations, and at various hematocrits. Knowledge of the durations t/sub s/, t/sub f/ and the maximum slope s of the curve during the intermediate phase, determined with the model, allows a means to study RBC aggregate growth.
24 citations
Cites background from "Analysis of erythrocyte aggregation..."
...It has already been experimentally shown that time variations of the ultrasonic backscattering coefficient determined from aggregating red blood cells in suspension have a sigmoid shape; the initial growth of the curve occurs faster and earlier as the degree of aggregation is enhanced [10], [11]....
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TL;DR: In this paper, a video-microscopic system was used to obtain dynamic images of erythrocytes during sedimentation under gravitational field, and the data obtained showed the variability in the formation of aggregates in different age groups.
Abstract: The erythrocytes form chain-like aggregates during sedimentation under gravitational field. The dynamic images of these are obtained by video-microscopic system by placing the erythrocyte suspension in plasma at hematocrit 5%, in a glass chamber of thickness 100 μm. The images at intervals of 2 min for 30 s duration are recorded. As the images are associated with high background noise, after digitization they are preprocessed for illumination correction, video de-interlacing, background subtraction, and deblurring, followed by post-processing involving edge enhancement, thresholding, median filtering and edge detection. By processing these images, to quantify the aggregation process, the morphometric parameters—projected aggregate area (PAA), projected aggregate perimeter (PAP) and form factor (FF), and sedimentation completion time (SCT) are obtained. To determine the variability of erythrocyte aggregation during human aging by this technique, blood samples from subjects of various age groups (from 20 to 60 years) are analyzed. The data obtained show the variability in the formation of aggregates in different age groups. The comparison in subjects of different age groups shows that the PAA, PAP and FF, and SCT are decreased significantly compared to that of subjects of age group 20–30 years. In subjects of 51–60 years, the formed aggregates are compact, which sediment faster compared to that of other age groups.
18 citations