Electronic Journal of Differential Equations,
Conf. 10 (2002), pp. 89-99.

Title: Modelling the interactions of mixtures of organophosphorus insecticides with
cholinesterase

Authors: Russell. L. Carr (Mississippi State Univ., MS, USA)  
   Howard W. Chambers (Mississippi State Univ., MS, USA)
   Janice E. Chambers (Mississippi State Univ., MS, USA)
   Seth F. Oppenheimer (Mississippi State Univ., MS, USA)
   Jason R. Richardson (Emory Univ., Atlanta, GA, USA)
 
Abstract: 
The organophosphorus (OP) insecticides are one of the most widely used and
important insecticide classes. These insecticides exert toxicity through
inhibition of the critical nervous system enzyme cholinesterase (ChE) which
functions to rapidly destroy the ubiquitous neurotransmitter acetylcholine. 
When ChE is inhibited, the acetylcholine accumulates, causing hyperactivity
within the cholinergic pathways. Considerable effort has gone into assessing
the risks of various OP insecticides. Unfortunately, people are often
exposed to different OP insecticides in different dosages at different or
overlapping times. The usual statistical methods seem inadequate to the task
of assessing the effect of OP mixtures. This paper will discuss a simple
model using systems of ordinary differential equations. Using this model, we
have had success in predicting the effect of cumulative in vitro OP compound
exposure in terms of ChE inhibition using data from experiments measuring
ChE inhibition by a single OP compound. We will describe our model and
compare our simulations to in vitro experiments where binary mixtures have
been used.


Published February 28, 2003.
Math Subject Classifications: 92C45
Key Words: Reaction kinetics; reaction modelling.