Erythrocyte aggregation at non-steady flow conditions: A comparison of characteristics measured with electrorheology and image analysis

Kaliviotis, Efstathios; Ivanov, Ivan; Antonova, Nadia; Yianneskis, M.

doi:10.3233/ch-2009-1251

Cited by 27 publications

(12 citation statements)

References 21 publications

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“…Erythrocyte aggregation at non-steady flow conditions in the Couette rheometric cell has been studied by Kaliviotis et al [ 21 ]. Electro-rheology was applied in parallel with optical shearing technique to study blood microstructural characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effects of Aggregation on Blood Sedimentation and Conductivity

Zhbanov

Yang

2015

PLoS ONE

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The erythrocyte sedimentation rate (ESR) test has been used for over a century. The Westergren method is routinely used in a variety of clinics. However, the mechanism of erythrocyte sedimentation remains unclear, and the 60 min required for the test seems excessive. We investigated the effects of cell aggregation during blood sedimentation and electrical conductivity at different hematocrits. A sample of blood was drop cast into a small chamber with two planar electrodes placed on the bottom. The measured blood conductivity increased slightly during the first minute and decreased thereafter. We explored various methods of enhancing or retarding the erythrocyte aggregation. Using experimental measurements and theoretical calculations, we show that the initial increase in blood conductivity was indeed caused by aggregation, while the subsequent decrease in conductivity resulted from the deposition of erythrocytes. We present a method for calculating blood conductivity based on effective medium theory. Erythrocytes are modeled as conducting spheroids surrounded by a thin insulating membrane. A digital camera was used to investigate the erythrocyte sedimentation behavior and the distribution of the cell volume fraction in a capillary tube. Experimental observations and theoretical estimations of the settling velocity are provided. We experimentally demonstrate that the disaggregated cells settle much slower than the aggregated cells. We show that our method of measuring the electrical conductivity credibly reflected the ESR. The method was very sensitive to the initial stage of aggregation and sedimentation, while the sedimentation curve for the Westergren ESR test has a very mild slope in the initial time. We tested our method for rapid estimation of the Westergren ESR. We show a correlation between our method of measuring changes in blood conductivity and standard Westergren ESR method. In the future, our method could be examined as a potential means of accelerating ESR tests in clinical practice.

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Section: Introductionmentioning

confidence: 99%

Effects of Aggregation on Blood Sedimentation and Conductivity

Zhbanov

Yang

2015

PLoS ONE

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“…A H-shaped microfluidic device, composed of two parallel side channels and a bridge channel, can effectively measure blood viscosity under various flow conditions 13 . RBC aggregation can be measured directly (microscopic observation methods) 14 15 , or indirectly. The latter includes measurement modalities such as erythrocyte sedimentation rate 16 , light reflection or transmission 17 , ultrasonic 18 19 and electrorheological methods 20 .…”

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confidence: 99%

Hybrid System for Ex Vivo Hemorheological and Hemodynamic Analysis: A Feasibility Study

Yeom

Kang

Lee

2015

Sci Rep

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Precise measurement of biophysical properties is important to understand the relation between these properties and the outbreak of cardiovascular diseases (CVDs). However, a systematic measurement for these biophysical parameters under in vivo conditions is nearly impossible because of complex vessel shape and limited practicality. In vitro measurements can provide more biophysical information, but in vitro exposure changes hemorheological properties. In this study, a hybrid system composed of an ultrasound system and microfluidic device is proposed for monitoring hemorheological and hemodynamic properties under more reasonable experimental conditions. Biophysical properties including RBC aggregation, viscosity, velocity, and pressure of blood flows are simultaneously measured under various conditions to demonstrate the feasibility and performance of this measurement system. The proposed technique is applied to a rat extracorporeal loop which connects the aorta and jugular vein directly. As a result, the proposed system is found to measure biophysical parameters reasonably without blood collection from the rat and provided more detailed information. This hybrid system, combining ultrasound imaging and microfluidic techniques to ex vivo animal models, would be useful for monitoring the variations of biophysical properties induced by chemical agents. It can be used to understand the relation between biophysical parameters and CVDs.

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“…To this extent the technique used for the development of the aggregation and integrity indices (equations 1 and 2) has been compared to other techniques and has been concluded that it can reveal features of blood microstructure identical to those obtained by other optical and electrorheology techniques [21,23,24]. In addition, direct comparison of data from optical shearing microscopy with results obtained from electrorheology techniques at identical flow conditions, but in different gaps (30 and 1000 m in optical microscopy and electrorheology respectively) have shown that there is an excellent agreement between the techniques for certain flow conditions, whereas discrepancies appear in the measurement with excessive aggregation [25].…”

Section: Discussionmentioning

confidence: 69%

Mechanics of the red blood cell network

Kaliviotis

2015

JCB

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Changes in the microstruture of blood caused by the red blood cell aggregation phenomenon affect the mechanical properties of the fluid. This fact has been extensively investigated in the past and it has been verified that the formation of rouleaux (the characteristic coin-pile like structures) and aggregates at low shear rates affect the flow and as a consequence the viscosity of the fluid is elevated. At physiological red blood cell concentrations and at low shear rates, however, in addition to rouleaux and aggregate formation an extended network is observed. The effects of network characteristics on the mechanical properties of blood have received relatively little attention in the literature and only a few studies provide quantitative data on this aspect of the blood flow. Quantitative data on network characteristics in view of the aggregation phenomenon illustrate that indeed different network configurations have different effects on the mechanical properties of the fluid. In this work, it is shown that changes in the viscosity of blood at specific flow conditions correlate with the changes in the mechanical characteristics of the red blood cell network.

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Erythrocyte aggregation at non-steady flow conditions: A comparison of characteristics measured with electrorheology and image analysis

Cited by 27 publications

References 21 publications

Effects of Aggregation on Blood Sedimentation and Conductivity

Effects of Aggregation on Blood Sedimentation and Conductivity

Hybrid System for Ex Vivo Hemorheological and Hemodynamic Analysis: A Feasibility Study

Mechanics of the red blood cell network

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