Modelling ion flux in red cells

The volume of a circulating red blood cell is a primary function of its water content; this being determined by the cellular amounts of ions such as K+ and Na+. Improper function of transport pathways of these can lead to reduced cell deformability, as occurs in Sickle-cell Anaemia and other disease states. Work in our laboratory has focussed on the kinetics of the calcium-activated potassium (Gardos) channel in the human red cell, and the role this transporter plays in regulation of cell volume. Whole cell 39K, 87Rb, 31P NMR spectroscopy was employed to monitor changes in cellular ion and water content. 19F NMR enabled prediction of the available free calcium using 5,5'-difluoro-l,2-bis(o-aminophenoxy)-ethane-N,N,N'N'-tetraacetic acid (5-F-BAPTA) as a calcium 'probe'. Concurrently a model of red cell ion flux has been written in Mathematica. This model numerically solves a system of time-dependent differential equations with rate constants and other parameters based on experimental evidence