fA [study of the starch-iodine complex: a modified colourimetric micro determination of amylase in biological fluids

The limitations, inaccuracies, and practical difficulties of saccharogenic methods are discussed. A modified colorimetric microdetermination of amylase is described in which the digestion of starch is measured by the decrease in the starch-iodine color. Experimental data show that there are two other serum factors that can also cause a fall-off in color: (1) an immediate 10-15 % depression of color, probably due to serum proteins and countered by using serum in the control; (2) an acid-serum fac-tor causing a progressive fall-off in color subsequent to the initial depression. Iodine prevents this, and must be added as soon as the acid has been added to stop the en-zyme activity. Results of 189 consecutive assays of human sera are presented. Amylase activity of duodenal aspirate has been determined simultaneously by the method described and the Lagerlof method. Results are compared. Changes in serum amylase and lipase levels in artificially produced pancreatitis in dogs are presented. Optimal conditions for amylase activity are reviewed, and in the light of these, differ-ent amyloclastic methods and their results compared. Achroic-point technics are briefly evaluated. F OR PURPOSES OF a study on experimentally induced pancreatitis in dogs (3), it was necessary to perform many assays of amylase in bio-logic fluids. In seeking the most suitable method, it soon became clear that the many established procedures were beset with shortcomings, and a reassessment of some aspects of these became imperative. There is increasing evidence that amyloclastic methods are far superior t