scholarly journals Spatiotemporal Distribution of Neurovascular Alignment in Remodeling Adult Rat Mesentery Microvascular Networks

2012 ◽  
Vol 49 (4) ◽  
pp. 299-308 ◽  
Author(s):  
Peter C. Stapor ◽  
Walter L. Murfee
Keyword(s):  
Spatiotemporal Distribution ◽  
Microvascular Networks ◽  
Adult Rat ◽  
Rat Mesentery

Analysis of primary valve structure along initial lymphatic networks in adult rat mesentery

2007 ◽  
Vol 21 (5) ◽  
Author(s):  
Walter L Murfee ◽  
Jeff W Rappleye ◽  
Geert W Schmid‐Schönbein
Keyword(s):  
Adult Rat ◽  
Rat Mesentery ◽  
Valve Structure

A One-Dimensional Mathematical Model for Studying the Pulsatile Flow in Microvascular Networks

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Qing Pan ◽  
Ruofan Wang ◽  
Bettina Reglin ◽  
Guolong Cai ◽  
Jing Yan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulsatility Index ◽  
Dynamic Models ◽  
Dynamic Properties ◽  
Microvascular Blood Flow ◽  
Integration Scheme ◽  
Microvascular Networks ◽  
Mean Values ◽  
One Dimensional ◽  
Rat Mesentery

Techniques that model microvascular hemodynamics have been developed for decades. While the physiological significance of pressure pulsatility is acknowledged, most of the microcirculatory models use steady flow approaches. To theoretically study the extent and transmission of pulsatility in microcirculation, dynamic models need to be developed. In this paper, we present a one-dimensional model to describe the dynamic behavior of microvascular blood flow. The model is applied to a microvascular network from a rat mesentery. Intravital microscopy was used to record the morphology and flow velocities in individual vessel segments, and boundaries are defined according to the experimental data. The system of governing equations constituting the model is solved numerically using the discontinuous Galerkin method. An implicit integration scheme is adopted to increase computing efficiency. The model allows the simulation of the dynamic properties of blood flow in microcirculatory networks, including the pressure pulsatility (quantified by a pulsatility index) and pulse wave velocity (PWV). From the main input arteriole to the main output venule, the pulsatility index decreases by 66.7%. PWV obtained along arterioles declines with decreasing diameters, with mean values of 77.16, 25.31, and 8.30 cm/s for diameters of 26.84, 17.46, and 13.33 μm, respectively. These results suggest that the 1D model developed is able to simulate the characteristics of pressure pulsatility and wave propagation in complex microvascular networks.

scholarly journals Lymphatic/Blood Endothelial Cell Connections at the Capillary Level in Adult Rat Mesentery

2010 ◽  
Vol 293 (10) ◽  
pp. spc1-spc1
Author(s):  
Jennifer L. Robichaux ◽  
Eleanor Tanno ◽  
Jeff W. Rappleye ◽  
Mariana Ceballos ◽  
William B. Stallcup ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Adult Rat ◽  
Rat Mesentery

scholarly journals Lymphatic/Blood Endothelial Cell Connections at the Capillary Level in Adult Rat Mesentery

2010 ◽  
Vol 293 (10) ◽  
pp. 1629-1638 ◽  
Author(s):  
Jennifer L. Robichaux ◽  
Eleanor Tanno ◽  
Jeff W. Rappleye ◽  
Mariana Ceballos ◽  
William B. Stallcup ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Adult Rat ◽  
Rat Mesentery

Relationship between structural and hemodynamic heterogeneity in microvascular networks

1996 ◽  
Vol 270 (2) ◽  
pp. H545-H553 ◽  
Author(s):  
A. R. Pries ◽  
T. W. Secomb ◽  
P. Gaehtgens
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Topological Structure ◽  
Blood Rheology ◽  
Experimental Information ◽  
Microvascular Networks ◽  
Rat Mesentery ◽  
Hemodynamic Characteristics ◽  
Flow Through ◽  
The Relationship

The relationship between structural and hemodynamic heterogeneity of microvascular networks is examined by analyzing the effects of topological and geometric irregularities on network hemodynamics. Microscopic observations of a network in the rat mesentery provided data on length, diameter, and interconnection of all 913 segments. Two idealized network structures were derived from the observed network. In one, the topological structure was made symmetric; in another a further idealization was made by assigning equal lengths and diameters to all segments with topologically equivalent positions in the network. Blood flow through these three networks was simulated with a mathematical model based on experimental information on blood rheology. Overall network conductance and pressure distribution within the network were found to depend strongly on topological heterogeneity and less on geometric heterogeneity. In contrast, mean capillary hematocrit was sensitive to geometric heterogeneity but not to topological heterogeneity. Geometric and topological heterogeneity contributed equally to the dispersion of arteriovenous transit time. Hemodynamic characteristics of heterogeneous microvascular networks can only be adequately described if both topological and geometric variability in network structure are taken into account.

Structure and hemodynamics of microvascular networks: heterogeneity and correlations

1995 ◽  
Vol 269 (5) ◽  
pp. H1713-H1722 ◽  
Author(s):  
A. R. Pries ◽  
T. W. Secomb ◽  
P. Gaehtgens
Keyword(s):  
Vessel Diameter ◽  
Hemodynamic Parameters ◽  
Strong Correlations ◽  
Microvascular Networks ◽  
True Value ◽  
Rat Mesentery ◽  
Coefficients Of Variation ◽  
Network Properties ◽  
The Mean ◽  
Intravascular Pressure

The objective of this study was to quantify the heterogeneity of topological, morphological, and hemodynamic parameters in microvascular networks and to identify functionally relevant correlations among these parameters. Seven networks in the rat mesentery (383-913 vessel segments per network) were examined, and measurements were made of segment generation, diameter, length, and hematocrit in all segments (n = 3,129) and of flow velocity (only in 3 networks, 1,321 segments). In addition, hematocrit, flow rate, and pressure were derived for all segments from a mathematical simulation. All parameters obtained exhibit heterogeneous distributions with coefficients of variation ranging from 0.28 (capillary diameter) to > 1.5 (volume flow and pressure gradient). Several strong correlations exist between parameters, e.g., discharge hematocrit increases with vessel diameter, and shear rate increases with intravascular pressure. Because of such correlations, the extrapolation from average values for "typical vessels" to network properties can lead to substantial errors. For example, the mean network transit time estimated based on averaged quantities is 6.5 s, which is about 60% higher than the true value (4.08 s). Simplified models of the vascular bed may therefore be inadequate to describe functional properties of the microcirculation.

EphB4 Expression Along Adult Rat Microvascular Networks: EphB4 Is More Than a Venous Specific Marker

2007 ◽  
Vol 14 (3) ◽  
pp. 253-267 ◽  
Author(s):  
Alyssa C. Taylor ◽  
Walter L. Murfee ◽  
Shayn M. Peirce
Keyword(s):  
Specific Marker ◽  
Microvascular Networks ◽  
Adult Rat
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