Document Detail

A compartmental capillary, convolution integration model to investigate nutrient transport and metabolism in vivo from paired indicator/nutrient dilution curves.
MedLine Citation:
PMID:  15649875     Owner:  NLM     Status:  MEDLINE    
Thirty-three paired indicator/nutrient dilution curves across the mammary glands of four cows were obtained after rapid injection of para-aminohippuric acid (PAH) plus glucose into the external iliac artery. For the measurement of extracellular volume and kinetics of nutrient uptake from indicator dilution curves, several models of solute dispersion and disappearance have been proposed. The Crone-Renkin models of exchange in a single capillary assume negligible washout of solutes from the extracellular space and do not describe entire dilution curves. The Goresky models include a distribution of capillary transit times to generate whole system outflow profiles but require two indicators to parametize extracellular behavior. A compartmental capillary, convolution integration model is proposed that uses one indicator to account for the extracellular behavior of the nutrient after a paired indicator/nutrient injection. With the use of an iterative approach to least squares, unique solutions for nonexchanging vessel transit time t(mu) and its variance sigma were obtained from all 33 PAH curves. The average of heterogeneous vascular transit times was approximated as 2sigma = 8.5 s. The remainder of indicator dispersion was considered to be due to washout from a well-mixed compartment representing extracellular space that had an estimated volume of 5.5 liters or 24% of mammary gland weight. More than 99% of the variation in the time course of venous PAH concentration after rapid injection into the arterial supply of the mammary glands was explained in an unbiased manner by partitioning the organ into a heterogeneous nonexchanging vessel subsystem and a well-mixed compartmental capillary subsystem.
Fulong Qiao; Donald R Trout; V Margaret Quinton; John P Cant
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-01-13
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  99     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-08-16     Completed Date:  2005-10-27     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  788-98     Citation Subset:  IM    
Dept. of Animal and Poultry Science, Univ. of Guelph, Guelph, Ontario, Canada N1G 2W1.
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MeSH Terms
Biological Transport, Active / physiology
Breast / blood supply*,  metabolism*
Capillaries / physiology*
Capillary Permeability / physiology*
Computer Simulation
Glucose / metabolism*
Indicator Dilution Techniques*
Metabolic Clearance Rate
Models, Biological*
p-Aminohippuric Acid / metabolism*
Reg. No./Substance:
50-99-7/Glucose; 61-78-9/p-Aminohippuric Acid

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

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