[Evaluation of serum enzyme levels considering biological half lives of enzymes--alteration of lactate dehydrogenase isoenzyme pattern due to computer simulation].

The rapid clearance of certain releasing enzymes from blood stream may modify their usefulness as markers of disease. Serum LD isoenzyme patterns are often quite different from those in the affected tissues. Such differences result from differences in the biological half lives of the individual isoenzyme. In order to reveal such phenomena, we applied the one-compartment model to simulate the time dependent changes in the serum LD isoenzyme patterns as a most simple model. When we simulated leukemic cells as an affected origin, LD isoenzyme patterns obtained at a stage of clinical deterioration or active stage, were characterized by a high proportion of LD-2, LD-3 and LD-4, and resembled those of the original leukemic cells. In general, strong similarities in alterations of LD isoenzyme patterns were obtained between the clinical observed time course and simulated time course. These changes in LD isoenzyme patterns are practically observed in the cases of leukemia, lymphoma, and so on. If the original organs are identical, then it is change of disease stage that is responsible for modification of variable LD isoenzyme patterns. Such phenomena must therefore be noted--in doing so, we shall be able to estimate the origin of enzyme release, disease stage, and prognosis.