For each tissue and organ modeled in the chemokinetic model,
the cytodynamic model calculates quantitatively the carcinogenic and/or
cytotoxic effects of the pollutant in the corresponding tissue
or organ. The approach adopted is an extension of the
Armitage-Doll model of carcinogenesis and follows the cytodynamic model
as outlined, for example, in [7, 3]. Note that this
type of model is able to handle hormetic behavior of a tissue
to an outside response, a feature of strong interests to
toxicologists [2]. The modeler has to specify the number
of different cell populations per compartment that should be modeled.
The dynamic behavior of each population is then governed by the
pollutant concentration inside the compartment (by a toxic or a mutagenic
effect) and by the population numbers of the other cell types.
The governing ordinary differential equations, however, can not be classified
according to some simple criterion. As a consequence, the user must specify
the right hand side of the equations explicitly in the source code
by modifying the subroutine `CMPCLLR` (file `compartment.f`)
accordingly.

The solver routine for the nonlinear system of ordinary differential equations is fully integrated into the routine for solving the chemokinetical equations described in the last chapter.

We describe some simple examples for the type of cytodynamic activity which can be modeled by this approach.

Wed Dec 22 12:25:31 CET 1999