Date of Award
Summer 1972
Document Type
Dissertation - Restricted
Degree Name
Doctor of Philosophy (PhD)
Department
Biomedical Engineering
First Advisor
Llaurado, Joseph G.
Second Advisor
Sances, Anthony
Third Advisor
Hosek, Ronald
Abstract
Biomedical engineering has as one of its functions the development and extension of man's understanding and control of life related processes. Theories developed in biology, experimental procedures of physiology and pharmacodynamics, and engineering approaches utilizing systems analysis and computer simulation of models all come together within this discipline. This dissertation will be concerned with the phenomenon of sodium movement and distribution between cells and their surrounding fluids. However, to extend present methods of analysis it is necessary to devise a way of modeling which can be applied generally to more than a few ideal situations. One of the severest restrictions on such general applications is the way many tissue systems change their sodium distributions once they are removed from their natural in vivo surroundings, and yet it is precisely by their isolation that one can probe deeper into their individual characterizations. To take the dramatic changes in sodium distribution into account, I have adapted compartmental modeling procedures using time varying transport to characterize sodium exchange in slices of liver tissue. Solutions in terms of transport rates as primary parameters are obtained by utilizing a large computer program which improves upon initial estimates of these transport rates using an iterative curve fitting procedure. Both experimental sodium tracer and tracee data curves are matched with the corresponding data simulated by the models employed. The resulting transport rates characterize the tissue at the beginning of its change in sodium distribution and, hence, better reflect the original in vivo state. Changes in these transport rates can then be used to quantify alterations of the state of the tissue produced by drugs or diseases which alter the sodium transporting processes...