beside confirming decreased elastin content in aneurysmal walls, these results show a concurrent increase of collagen cross-links. Since total collagen markers were decreased (decreased 4-hypro and 5-hylys) it is reasonable to suggest that in aneurysmal aortic walls old collagen accumulates cross-links while new collagen biosynthesis is somehow defective.

No abstract

Since the metabolic activity of the colonic flora plays a definite role in colon cancer and an increased incidence of this disease is reported after cholecystectomy, we studied the metabolic activity of the colonic flora in a group of postcholecystectomy patients and matched controls by measuring, as representative end products of the bacterial metabolism, their fecal bile acids (BA), fecal 3-methylindole (SK) and indole (IN), and respiratory methane and hydrogen. Patients had significantly higher SK and lower IN, and, among BA, higher lithocholic (LCA) and chenodeoxycholic acid concentrations and LCA/deoxycholic acid ratio in the stools than controls. Similar differences from controls were reported for colon cancer. Comparable bacterial metabolic activities are thus operative in the large bowel of postcholecystectomized and colon cancer patients. This supports the biological plausibility of the association of cholecystectomy and colon cancer.

Compared to homologous tissues from adult animals, rapidly growing embryonic and fetal tissues contain large amounts of collagen proline hydroxylase. Lung and skin from scorbutic guinea pigs contain one-third as much enzyme as normal tissues do. A rapid increase in proline hydroxylase occurs on the 2nd day of formation of granuloma after injection of carrageenan and on the 4th day of wound healing. The increase in enzyme activity is associated with the onset of collagen biosynthesis and deposition.