The intestinal mucosal barrier to intact antigenic protein. Difference between colon and small intestine.

The integrity of the normal mature intestinal mucosal barrier to unaltered proteins was evaluated with tritiated bovine albumin in rats. Intact H3-BSA placed into either colon or small intestinal lumen regularly reached the bloodstream in quantities sufficient to be antigenic or toxigenic, although the fraction of H3-BSA absorbed from the colon (0.13 per cent) was significantly smaller than that absorbed from the small intestine (1.7 per cent). These studies support the possibility that uptake of ingested or bacterial antigens from the normal gut may be involved in the pathogenesis of local intestinal and systemic disease in man.

Electrophoretic identification of an isoenzyme of amylase which increases in serum in liver diseases.

Isoenzymes of amylase were studied in serum from 72 persons by means of polyacrylamide gel electrophoresis and a direct saccharogenic assay for amylase activity. In 37 normal individuals, there were two major peaks of amylase actvity with mobilities similar to pancreatic and salivary amylases. In 11 patiets with acute pancreatitis, the area of activity corresponding with pancreatic amylases increased disproportionately. Electrophoretic patterns of amylase activity in normal and pancreatitis urine were almost identical to the respective serum patterns from the same persons. In contrast, a prominent slower-moving peak of amylase activity occurred in the serum of 8 of 12 patients who had hyperamylasemia associated with various liver diseases. Traces of this third peak were identifiable in one-third of normal serum specimens, but no increases in its activity were observed in any specimen from 11 patients with pancreatitis or from 12 other patients with hyperamylasemia unassociated with liver disease. The slower-moving peak was absent from the urine of patients whose serum contained it. The origin of the slower-moving serum amylase appearing in patients with liver disease is not established by these studies. It is possible either that a hepatic amylase is liberated from damaged liver cells or that the metabolism of an amylase not originating in the liver is altered as a result of liver dysfunction.

Inhibition of serum and urine amylase activity in pancreatitis with hyperlipemia.

In 6 of 7 patients with acute pancreatitis and hyperlipemia, inhibition of serum amylase activity was detected by dilution of the serum before assaying for amylase and by correcting for tthe dilution factor. In 4 patients the inhibition phenomenon disappeared within the first few days of hospitalization as the elevated serum triglycerides fell. However, in 2 others there was no relation between triglyceride level and amylase inhibition. Removal of the excess serum lipids by ultracentrifugation did not eliminate the inhibition of amylase activity. Inhibition of amylase activity also occurred in the urine of these patients. No amylase inhibition was demonstrable in lipemic serum from patients without pancreatitis or in pancreatitis serum to which excess lipids were added. The data suggest the presence of a circulating inhibitor of amylase, distinct from the elevated serum lipids, in the serum and urine of patients with acute pancreatitis associated with hyperlipemia. The diagnosis of acute pancreatitis in the patient with abdominal pain and lactescent serum can be facilitated by correcting the serum amylase activity by dilution.