Document Detail


A three-pathway pore model describes extensive transport data from Mammalian microvascular beds and frog microvessels.
MedLine Citation:
PMID:  12483547     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To show that a three-pathway pore model can describe extensive transport data in cat and rat skeletal muscle microvascular beds and in frog mesenteric microvessels. METHODS: A three-pathway pore model was used to predict transport data measured in various microcirculatory preparations. The pathways consist of 4- and 24-nm radii pore systems with a 2.5:1 ratio of hydraulic conductivities and a water-only pathway of variable conductivity. The pore sizes and relative hydraulic conductivities of the small- and large-pore systems were derived from a model fit to reflection coefficient (sigma) data in the cat hindlimb. The fraction (alpha(w)) of total hydraulic conductivity (L(p)) or hydraulic capacity (L(p)S) contributed by the water-only pathway was uniquely determined for each preparation by a fit of the three-pathway model (parameters fixed as above) to sigma data measured in that preparation. These parameter values were unchanged when the model was used to predict diffusion capacity (permeability-surface area product, P(d)S) data in the cat or rat preparations or diffusional permeability (P(d)) data in frog microvessels. The values for L(p) or L(p)S used to predict diffusional data in each preparation were taken from the literature. Predictions of P(d) ratios for solute pairs were also compared with experimental data. RESULTS: The three-pathway model closely predicted the trend of P(d)S or P(d) experimental data in all three preparations; in general, predicted P(d) ratios for paired solutes were quite similar to experimental data. For these comparisons, the only parameter varied between these preparations was alpha(w). It varied considerably, from 7 to 16 to 41% of total in frog, rat, and cat preparations. Individual P(d)S or P(d) experimental data were closely predicted in the cat but somewhat overestimated in the frog and rat. This result could be due the use of L(p) or L(p)S values in the model that were affected by methodological problems. Calculated hydraulic conductivities of the water-only pathway in the three preparations were quite similar. CONCLUSIONS:: These results support the hypothesis of a common structure of the transmembrane pathways in these three, very different, microcirculatory preparations. What varies considerably between them is the total number of solute-conducting pathways, but not their dimensions, nor the hydraulic conductivities of their water-only pathways. Because of the wide variation of alpha(w) among these preparations, the ratio of P(d) to L(p) for any solute is not constant, but the deviation from constancy may not be detectable because of errors in the experimental data.
Authors:
Matthew B Wolf
Related Documents :
11588827 - On the hydro-dispersive equivalence between multi-layered mineral barriers.
23155417 - Evaluation of forest recovery over time and space using permanent plots monitored over ...
22814937 - Pebbles and pebblejuggler: software for accurate, unbiased, and fast measurement and an...
24462897 - Spatial invasion dynamics on random and unstructured meshes: implications for heterogen...
22819177 - Input permutation method to detect active voxels in fmri study.
10206397 - Combined rigid and flexible endoscopic removal of a bb foreign body from a peripheral b...
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Microcirculation (New York, N.Y. : 1994)     Volume:  9     ISSN:  1073-9688     ISO Abbreviation:  Microcirculation     Publication Date:  2002 Dec 
Date Detail:
Created Date:  2002-12-16     Completed Date:  2003-11-20     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9434935     Medline TA:  Microcirculation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  497-511     Citation Subset:  IM    
Affiliation:
Department of Pharmacology and Physiology, University of South Carolina School of Medicine, Columbia, South Carolina 29208, USA. wolf@med.sc.edu
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Biological Transport
Capillary Permeability*
Cats
Diffusion
Microcirculation / physiology*
Models, Biological*
Muscle, Skeletal / blood supply
Porosity
Ranidae
Rats
Serum Albumin / metabolism
Splanchnic Circulation
Sucrose / metabolism
Grant Support
ID/Acronym/Agency:
HL-39691/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Serum Albumin; 57-50-1/Sucrose

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Development of mouse cremaster transplantation model for intravital microscopic evaluation.
Next Document:  ZM323881, a novel inhibitor of vascular endothelial growth factor-receptor-2 tyrosine kinase activit...