selective evaluation of two urinary enzymes (nag and aap) before and after unilateral shock wave lithotripsy

biological effects extracorporeal shock wave lithotripsy (eswl) is not precisely known. we have evaluated two urinary enzymes activity n-acetyl-b-d-glucosamine (nag) and alanine amino peptidase (aap) before and after unilateral eswl as markers for renal parenchymal damage. forty eight patients with kidney stones (mean age 39) who had presented for the first time or at least one year after their previous lithotripsy underwent eswl. urinary specimens were collected before and after first, third and seventh days of lithotripsy and nag, aap were evaluated. these enzymes displayed the greatest activity 24 hours after eswl with significant difference compared to the control group, (p 2 cm) is probably related to injury resulting from passage of smaller stones, produced after lithotripsy of a large stone, and it is suggested that these patients are treated with a safer procedure.