Abstract: The present invention provides a method for assaying hyaluronic acid more precisely and more simply than the conventional method, and relates to (1) an assay method for hyaluronic acid comprising contacting a reagent containing hyaluronic acid binding protein modified with a labeled substance with a sample containing hyaluronic acid to form a complex of the hyaluronic acid and the labeled hyaluronic acid binding protein, separating the complex and the free labeled hyaluronic acid binding protein, and measuring the labeled substance in the complex or the labeled substance in the free labeled hyaluronic acid binding protein, and (2) a reagent for an assay of hyaluronic acid comprising a labeled hyaluronic acid binding protein, which is prepared by binding a labeled substance and a hyaluronic acid binding protein through an antibody to the hyaluronic acid binding protein.

Abstract: This invention is intended to provide a process by which a complex formed by the interaction between one or more analytes to be measured and affinity substance can be more effectively separated from substances existing together therewith which tend to affect the detection of the complex, for example, free affinity substance, by using high pressure liquid chromatography (HPLC); and a process for measuring a trace component by utilizing said separating process.This invention is characterized in that a substance which has been modified with a substance capable of changing properties of the complex (a separation-improving substance) and has affinity for the complex is attached to the complex. Because of this characteristic, the invention is effective in that the position of elution of said complex in the HPLC can be freely controlled.

Abstract: A fulgimide derivative of the formula: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 are independently alkyl cycloalkyl aryl etc.; R.sup.4 is thienyl, indolyl, furyl, etc.; X is a divalent organic residue; and R is amino, OH, etc., or a vinyl group, has a photochromic action and can be used for producing photochromic polymers and copolymers.