To determine if human lipase is inactivated by trypsin and chymotrypsin, we intubated 22 human subjects with an oroduodenal tube and stimulated pancreatic secretion with cholecystokinin octapeptide. The duodenal aspirate from each subject was divided into a control and a test sample and incubated in a 37 degrees C water bath for 2 h. An inhibitor of trypsin or chymotrypsin or more of one of these enzymes was added to the test sample. We found that the loss of lipase activity was partly prevented by inhibiting trypsin with aprotinin (910 KU/ml; P = 0.03) and was accelerated by adding bovine trypsin (2.5 mg/ml; P = 0.01). Inhibiting chymotrypsin with turkey egg white (2.5 mg/ml) totally abolished the loss of lipase activity (P = 0.01), and addition of bovine chymotrypsin (5 mg/ml) accelerated the loss of lipase activity more than adding trypsin (P = 0.01). After inhibiting chymotrypsin (to maintain lipase activity), increasing trypsin activity by adding a single or repeated doses of trypsin did not decrease lipase activity. Conversely, the addition of a single dose of chymotrypsin after inhibiting trypsin activity markedly decreased lipase activity (P less than 0.004). In conclusion, chymotrypsin is a more potent inactivator of human lipase than trypsin; chymotrypsin inactivates lipase in the absence of trypsin, but trypsin inactivation of lipase requires chymotrypsin.
To estimate the risk of pancreatic cancer after gastric surgery for benign disease, we followed all 336 residents of Olmsted County, Minnesota, who had surgical treatment for benign peptic ulcer disease during the years 1935 to 1959. These patients were followed for 6549 person-years of observation. Pancreatic cancer developed in only one patient although 1.6 primary pancreatic cancers were expected (relative risk 0.64,95% confidence interval, 0.02 to 3.53) based on pancreatic cancer incidence rates for the general population of Olmsted County. We conclude that in our study the incidence of pancreatic cancer is not significantly increased after gastric surgery. Cancer 60245-247,1987.
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