No abstract

No abstract

No abstract

No abstract

perimental colon carcinoma in mice, indicating that the abnormal metabolism of sphingomyelin is linked to colon carcinoma development. However, the changes 1 Department of Medicine, Lund University Hospital, Lund, Sweden.in sphingomyelinase (SMase) activity in colon carcinoma have not been directly studied. The authors identified, specifically in the intestine, a distinctive alkaline 2 Research Park Ideon, Swedish Dairies AssociSMase that differs from the known acidic and neutral SMases. The functions and ation, Lund, Sweden.clinical implications of the enzyme are unknown. This study examined the changes 3 Department of Cell Biology, Lund University in all three SMase activities in human colorectal carcinoma. Hospital; Lund, Sweden. METHODS.Tissue samples were taken from colorectal carcinoma and normal mucosa from 18 patients. After homogenization, the activities of acidic, neutral, and alkaline SMase, as well as ceramidase and alkaline phosphatase, were determined. The enzyme activities in cancer tissue were compared with normal tissue from the same patients. RESULTS.In the normal tissue, there is an activity gradient from the ascending colon to the rectum for neutral and alkaline SMases but not for acidic SMase. In colorectal carcinoma, alkaline SMase activity was preferentially decreased by 75%, whereas acidic and neutral SMase activity decreased by 30% and 50%, respectively. No changes could be found for either ceramidase or alkaline phosphatase activity. CONCLUSIONS.Alkaline SMase activity preferentially decreases in human colorectal carcinoma, suggesting a regulatory role of the enzyme in colon mucosa cell proliferation.

The alkaline sphingomyelinase (SMase) was first found in rat intestinal brush border. The important roles of this enzyme in digestion of sphingomyelin and in mucosal cell proliferation have been suggested. In the present work, the distribution of the alkaline SMase in the tissues of human beings and animals have been studied. By assaying the enzyme activity in human biopsy samples, we found that the alkaline SMase activity was absent in the stomach, increased in the duodenum, present at high levels in the small intestine, and slightly declined in the colon and rectum. High activities were found similarly in the intestinal contents of the healthy adults and infants. The activities were also found in the intestinal mucosa of rats, normal and germ-free mice, and hamsters with the same distribution pattern as in humans, but not in the intestinal mucosa of guinea pigs. Apart from the intestinal tract, a SMase activity preferring alkaline pH was identified in human and guinea pig bile, but not in the bile of rat, pig, sheep, and cow. No activity was found in either pancreatic tissue or pancreatic juice in all species tested, and none was detected in human urine and milk. In conclusion, alkaline SMase exists predominantly in the digestive system with considerable tissue and species differences.

Objective: To evaluate the impact of an extruded muesli product based on b-glucan-rich oat bran on postprandial glycaemia and insulinaemia. Subject/Design: The study is divided in two series. Blood glucose and serum insulin responses were studied after subjects consuming test meals including a serving of muesli with 3 g (series 1) and 4 g (series 2) of b-glucans, respectively. The muesli was a component in a single serving packet with muesli and yoghurt. This was served together with white wheat bread in the morning after an overnight fast. The compositions were standardized to contain 50 g available carbohydrates. As a reference meal a serving packet without b-glucans was included. The study was performed at Applied Nutrition and Food Chemistry, Lund University, Sweden. Nineteen and thirteen healthy volunteers with normal body mass index were recruited for series 1 and 2, respectively. Results: Muesli with 3 g of b-glucans, included in a mixed bread meal, gave no significant differences in glycaemic response compared to a reference meal without muesli and b-glucans. In contrast, muesli with 4 g of b-glucans significantly (Po0.05) lowered the glucose and insulin responses compared to the reference meal. Conclusions: Muesli enriched with 4 g of b-glucans reduces postprandial glucose and insulin levels to a breakfast based on high glycaemic index products. A total of 4 g of b-glucans from oats seems to be a critical level for a significant decrease in glucose and insulin responses in healthy people.

No abstract