Scatchard fit program for M

Richard D Thorne rdtst+ at
Tue Jul 27 13:55:27 EST 1993

Nick Holford, Dept Pharmacology & Clinical Pharmacology

> ......A program called LIGAND that
> does the right thing using non-linear regression and solving for
> multiple ligands and binding sites was written in the late 60s Munson
> and Rodbard at the NIH. It has been ported in various forms e.g. SCATFIT
> in PL/I and BIND in QuickBasic (DOS). I cannot help you with a Mac
> implementationtion but just the warning about straight line fitters
> which are guaranteed to get the wrong answer except when there is no
> noise in the data.

  In my experience the output from Rodbard et al program and using the logistic
 equation is very slight.  Errors can be minimized by weighting.  The refs
 below may be of interest.  Richard

1) DeLean, J., Munson, P. and Rodbard, D. (1978) Simultaneous analysis of
families of sigmoidal curves  application to bioassay, radioligand assay, and
physiological dose-response curves, Am. J. Physiol., 235:E97-E102.

2) Guardabasso, V., Munson, P. and Rodbard, D. (1988) A versatile method for
simultaneous analysis of families of curves, FASEB J, 2:209-215.

3) Guardabasso, V., Rodbard, D. and Munson, P. (1987) A model-free approach to
estimation of relative potency in dose-response curve analysis, Am. J. Physiol.,

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