Asymptotic forms of tracer clearance curves: Theory and applications of improved extrapolations

Bass L., Aisbett J. and Bracken A.J. (1984) Asymptotic forms of tracer clearance curves: Theory and applications of improved extrapolations. Journal of Theoretical Biology, 111 4: 755-785. doi:10.1016/S0022-5193(84)80266-0


Author Bass L.
Aisbett J.
Bracken A.J.
Title Asymptotic forms of tracer clearance curves: Theory and applications of improved extrapolations
Journal name Journal of Theoretical Biology   Check publisher's open access policy
ISSN 1095-8541
Publication date 1984-12-21
Sub-type Article (original research)
DOI 10.1016/S0022-5193(84)80266-0
Open Access Status Not yet assessed
Volume 111
Issue 4
Start page 755
End page 785
Total pages 31
Subject 1100 Agricultural and Biological Sciences
1300 Biochemistry, Genetics and Molecular Biology
2400 Immunology and Microbiology
2604 Applied Mathematics
2611 Modelling and Simulation
2613 Statistics and Probability
2700 Medicine
Abstract Tracer clearance curves are conventionally extrapolated beyond times of observation by using monoexponential asymptotic forms. The inadequacy of the resulting predictions, especially as to the mean transit time and quantities derived from it, has been previously demonstrated experimentally. Here improvements in extrapolations and in the resulting predictions are derived theoretically and tested on previously published data, venous as well as externally recorded. First, secure lower bounds on the mean transit times are constructed, and shown to be much higher than conventional outright estimates for venous data (twice as high in some cases). Next, new asymptotic forms of tracer clearance curves from kinetically heterogeneous systems are derived; they are not monoexponential, but they are as robust, contain as few parameters and are as easily connected to data. It is shown theoretically that for real organs these new asymptotic forms should extrapolate and predict better than monoexponentials, and this is demonstrated on previously published venous data from perfused muscle. In particular, the resulting outright predictions of mean transit times are substantially better than the best lower bounds. Furthermore, a correction is derived to the standard estimate of the rate of regional cerebral blood flow. In an application to previously published data recorded externally, that correction reduces the estimated flow rate by 4%.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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