Temporal variations of the cell-free layer width may enhance NO bioavailability in small arterioles: Effects of erythrocyte aggregation

2011 ◽  
Vol 81 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Peng Kai Ong ◽  
Swati Jain ◽  
Sangho Kim
Keyword(s):  
Temporal Variations ◽  
Erythrocyte Aggregation ◽  
Free Layer ◽  
Layer Width ◽  
No Bioavailability ◽  
Cell Free Layer

Temporal and spatial variations of cell-free layer width in arterioles

2007 ◽  
Vol 293 (3) ◽  
pp. H1526-H1535 ◽  
Author(s):  
Sangho Kim ◽  
Robert L. Kong ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Correlation Length ◽  
Vessel Diameter ◽  
Temporal Variations ◽  
Hydraulic Pressure ◽  
Free Layer ◽  
Layer Width ◽  
Mean Width ◽  
The Mean ◽  
Non Gaussian ◽  
Cell Free Layer

Separation of red blood cells and plasma in microcirculatory vessels produces a cell-free layer at the wall. This layer may be an important determinant of blood viscosity and wall shear stress in arterioles, where most of the hydraulic pressure loss in the circulatory system occurs and flow regulatory mechanisms are prominent. With the use of a newly developed method, the width of the cell-free layer was rapidly and repeatedly determined in arterioles (10- to 50-μm inner diameter) in the rat cremaster muscle at normal arterial pressure. The temporal variation of the cell-free layer width was non-Gaussian, but calculated mean and median values differed by <0.2 μm. The correlation length of the temporal variations downstream (an indication of mixing) was ∼30 μm and was independent of pseudoshear rate (ratio of mean velocity to vessel diameter) and of vessel diameter. The cell-free layer width was significantly different on opposite sides of the vessel and inversely related. Increasing red blood cell aggregability reduced this inverse relation but had no effect on correlation length. In the diameter range studied, the mean width of the cell-free layer increased from 0.8 to 3.1 μm and temporal variations increased from 30% to 70% of the mean width. Increased aggregability did not alter either relationship. In summary, the cell-free layer width in arterioles is diameter dependent and shows substantial non-Gaussian temporal variations. The temporal variations increase as diameter increases and are inversely related on opposite sides of the vessel.

Quantitative evaluation of flow dynamics of erythrocytes in microvessels: influence of erythrocyte aggregation

1995 ◽  
Vol 268 (5) ◽  
pp. H1959-H1965 ◽  
Author(s):  
M. Soutani ◽  
Y. Suzuki ◽  
N. Tateishi ◽  
N. Maeda
Keyword(s):  
Flow Resistance ◽  
Circulatory System ◽  
Flow Dynamics ◽  
Erythrocyte Aggregation ◽  
Intensity Change ◽  
Image Analyzer ◽  
Free Layer ◽  
High Shear Rates ◽  
Suspension Viscosity ◽  
Cell Free Layer

Effects of erythrocyte aggregation on the flow dynamics of erythrocytes in microvessels were examined quantitatively by perfusing human erythrocytes suspended in isotonic medium containing various concentrations of dextran (70,400 avg mol wt, Dx-70) into a part of the microvascular bed isolated from rabbit mesentery. Thickness of the marginal cell-free layer was measured with an image analyzer, total flow resistance was determined on the basis of the perfusion pressure-volume flow relationship, and homogeneity of erythrocyte flow was evaluated by the power spectrum obtained by the fast Fourier transform of the light intensity change monitored on single microvessels. With increasing dextran concentration, suspension viscosity of erythrocytes at high shear rates increased linearly and thickness of the cell-free layer increased in a sigmoidal fashion. Flow resistance increased relatively little over the range of dextran concentrations in which the cell-free layer increased most rapidly. Furthermore, the flow pattern of erythrocytes in microvessels became inhomogeneous. In conclusion, the present study shows that Dx-70-induced erythrocyte aggregation results in increased flow resistance in the circulatory system, even through the widening of the cell-free layer tends to reduce the resistance and also results in inhomogeneous flow of erythrocytes in microvessels.

scholarly journals Effects of cell‐free layer width and its variability on wall shear stress in arterioles

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
BumSeok Namgung ◽  
Peng Kai Ong ◽  
Paul C Johnson ◽  
Sangho Kim
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Free Layer ◽  
Layer Width ◽  
Wall Shear ◽  
Cell Free Layer

A comparative study of histogram-based thresholding methods for the determination of cell-free layer width in small blood vessels

2010 ◽  
Vol 31 (9) ◽  
pp. N61-N70 ◽  
Author(s):  
Bumseok Namgung ◽  
Peng Kai Ong ◽  
Yun Hui Wong ◽  
Dohyung Lim ◽  
Keyoung Jin Chun ◽  
...  
Keyword(s):  
Comparative Study ◽  
Blood Vessels ◽  
Free Layer ◽  
Layer Width ◽  
Cell Free Layer

A Computer-Based Method for Determination of the Cell-Free Layer Width in Microcirculation

2006 ◽  
Vol 13 (3) ◽  
pp. 199-207 ◽  
Author(s):  
Sangho Kim ◽  
Robert L. Kong ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Free Layer ◽  
Layer Width ◽  
Computer Based ◽  
Cell Free Layer

scholarly journals Spatial and temporal variations of cell‐free layer in arterioles

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Robert Li‐Chung Kong ◽  
Sangho Kim ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Free Layer ◽  
Cell Free Layer
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