Fluxplus, a microcomputer program for interactive calculation of 'in vitro' solute fluxes, uptakes and accumulations in studies of intestinal transport

A new microcomputer program for interactive comparisons, analysis and calculation of in vitro solute transepithelial fluxes and nutrient uptakes and accumulations by intestinal tissues is described. The program is written in Microsoft GWBASIC for the widely distributed IBM-PC. Flux, uptake and accumulation values are obtained by computation from initial sequential data files and stored in sequential or random-orgaized files, depending on the specific process. Computed unidirectional fluxes are saved together with their associate electrical variables. The program calculates univariate statistics for unidirectional and net fluxes, and allows comparisons between selected groups of experiments by using the Student's t-test. An homocedasticity test is also provided. Active uptake or accumulations of solutes are calculated by substracting the predicted diffusive values at a determined concentration to total uptake or accumulation and from this, kinetic parameters are computed. The program was designed to be user-friendly and includes several functions to permit the user to manage and examine stored data. Examples of outputs illustrate applications of the program.