A BASIC program is presented to calculate extracellular space, ion and water contents, and ion concentrations in biological tissue treated as a two-compartment system, cellular and extracellular. The program requires that four experimentally determined variables be entered for each ion species to be analyzed, if the size of the extracellular compartment is known or to be assumed: tissue ion content, plasma ion concentration, and wet and dry tissue weights. If the extracellular compartment is to be quantified, then two options are available: first, morphometric analysis to obtain the mean ratio of extracellular area to tissue area; second, analysis of the tissue content and plasma concentration of a marker which is confined to the extracellular compartment after it is injected intravenously and allowed to equilibrate. All other required input data are obtained from the literature or analytical protocol and may be treated as constants. Although the program was designed for in vivo determinations of ion and water distributions in cardiac muscle, it may be generally applied to other tissues and experimental conditions directly or with minor modifications. © 1982.
Macchia, D. D., & Polimeni, P. I. (1982). A program in BASIC for calculation of tissue extracellular space and ion distributions in vivo using morphometric and/or extracellular tracer methods. Computers and Biomedical Research, 15(6), 592–597. https://doi.org/10.1016/0010-4809(82)90020-9