MEASUREMENT OF URINARY DESMOSINE AS AN INDICATOR OF ACUTE PULMONARY-DISEASE

A modified radioimmunoassay (RIA) for desmosine in the urine was inves tigated as a tool for the rapid estimation of lung elastin catabolism. Cystic fibrosis (CF) and oxygen toxicity were chosen as conditions th at might show altered elastin destruction, Using an antibody bound to magnetic particles the RIA was adapted to handle large numbers of samp les requiring only 50 mu l or urine. The experiments show that it was not necessary to hydrolyze or extract the urine prior to assay and tha t collecting spot urines and normalizing the data to urine creatinine gives the same interpretation of the data as total desmosine in a 24-h our collection. Urine desmosine levels were elevated in 10 of 16 patie nts with CF; however, daily fluctuations were considerable in some sub jects, varying as much as 5-fold and underlining the importance of ass aying several consecutive days of urine in acute disorders for an accu rate estimate of desmosine excretion. The RIA for desmosine is a rapid and sensitive assay that requires no sample preparation and could be applied to clinical situations that require large numbers of samples.