comparison of a group of patients undergoing an operation of moderate severity ( vagotomy and pyloroplasty or cholecystectomy ) with those having the more severe procedure of resection of aortic aneurysm with dacron graft replacement suggests that these general changes in amino acid concentrations do not appear to be due to the severity of the operation , although cystine levels were lower , and phenylalanine levels were higher , in the graft-replacement group .
C0184661
procedure
C0543467
operation