NONLINEAR MATHEMATICAL-MODEL FOR THE INVIVO DETERMINATION OF KUPFFER CELLS NUMBER AND RATE OF PHAGOCYTOSIS OF RADIOCOLLOIDS IN RATS

In order to perform a quantification of the hepatic RES function, a mathematical model of the colloids phagocytosis was constructed and validated in normal and partially hepatectomised rats. The experimental design consisted of the collection of successive blood samples for the measurement of radiocolloids time courses after the injection of different doses of gelatin colloids (0.075-5 mg of gelatin/100 g body wt). The unknown parameters were estimated by method of maximum likelihood using a second order algorithm. A good fit between experimental and simulated data was obtained for a large range of injected doses using a single set of parameters. Comparisons of parameters values between normal and hepatectomised rats were found to be consistent with the hepatectomy ratio. This computerised estimation of parameters provides a determination of both the total number of Kupffer cells and the mean time of a complete phagocytosis cycle which cannot be obtained by classical approaches. © 1979.