Equations describing the binding reactions.

Cells line the walls of the hollow fiber tube in our model and growth factor can bind to both receptors (R) or HSPG (H) to form complexes (C or G, respectively). These complexes can dimerize (C2 or G2,) or form heterodimers (T) that can then form higher order complexes (T2). The equations that describe the binding reactions are listed as well as the parameters (Table 2) and initial conditions used for the simulations.The initial condition for the FGF-2 concentration (F) was based on the amount of FGF-2 injected and the volume of inlet reservoir as described in Materials and Methods. The concentration is assumed to be uniform across the entrance. The receptor and HSPG densities were the initial conditions for R and H respectively. All other variables had an initial value of zero.