THE IDENTIFICATION OF A FLUORESCENT REDUCING SUBSTANCE IN THE URINE OF PATIENTS WITH RHEUMATOID ARTHRITIS: THE EXCRETION OF 3-HYDROXYANTHRANILIC ACID IN THIS AND OTHER CONDITIONS.
The report that 2,5-dihydroxyphenylpyruvic acid occurs in the urine of patients with collagen disease has not been confirmed, and no evidence was found for regarding collagen disease as being due to an inherent error in tyrosine metabolism as suggested by Japanese workers.A strongly reducing substance was conspicuous in the urine of patients with rheumatoid arthritis but not in that of normal persons. This substance was identified as 3-hydroxyanthranilic acid (3-HAA).A method is described for the measurement of 3-HAA in urine, employing ether extraction, paper chromatography in a formate solvent, and visual assessment by fluorescence in ultra-violet light and colour with Ehrlich's reagent. Normal persons excreted from less than 125 to 375 mug./day (average rather lower than 200 mug./day); those suffering from rheumatoid arthritis excreted from less than 125 to 2,250 mug./day (average 820 mug./day). The excessive excretion of 3-HAA in persons with rheumatoid arthritis was investigated in terms of other aspects of the activity of the disease. Some relationship was suggested between excretion levels, the erythrocyte sedimentation rate, and the sensitized sheep cell test. Cases of osteoarthritis, other orthopaedic conditions, and miscellaneous diseases were examined. A few of the latter, including diseases of the haemopoietic system, were associated with increased excretion of 3-HAA.
McMillan
M
M
Department of Clinical Chemistry, Edinburgh Royal Infirmary.