Disease model

Introduction

In the very beginning of the project, we focused on the duodenum and the iron absorbed by it. In order to determine if a flush treatment strategy was viable, we first had to model the behaviour of the duodenum regarding iron absorption.

Observations

60% of iron absorption takes place in the duodenum, the last 40% in the jejunum. The duodenum is located at the upper intestines, right after the stomach, and is usually 300mm long.

Figure 1 : Overview of the iron regulation system in human body.

A healthy person absorbs about 10% of the daily iron uptake(2 mg), while a hemochromatosis person's absorption varies between 50% and 100% of the daily iron uptake^[1].

Goals

This model is the first step for a sick person with treatment model . So, we want to have a realistic base for the final model.

Assumptions

Constant iron flow
Homogeneous fluid
The patient ingests 20mg of iron per day (Guideline Daily Amounts)

Materials and methods

The duodenum is a cylindrique pipe throw by a homogeneous fluid. So, we three step in the model: the filling of duodenum, steady state step and the emptying. This model have two state variable : iron disolved in the middle (S) and iron absorbed (A).
We considere a constant iron pulse every second arrive in the duodenum. S have a linear composant Sp who represent the pulses. We have the emptying compopsant and finally the absorption composant. We assume a linear absorption and a negative feedback regulation for A. Finally :