Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein digestion and absorption was studied in rats with 6-week-old surgically constructed self-filling intestinal blind loops and steatorrhea, ie, blind-loop animals and controls were fed a 14C-labeled protein meal containing a nonabsorbable marker, 51CrCl3, and sacrificed 1 or 2 hr later. Intestinal contents were analyzed for 14C, 51Cr, protein, trypsin, and the products of digestion. At 1 hr, 14C absorption was greater in controls, but at 2 hr there was no difference in absorption between the two groups. Marker studies showed that blind-loop filling resulted in a delay of the progression of intestinal contents distally. Intraluminal trypsin and porteolysis were similar in the two groups. Endogenous protein was greater in the blind-loop animals. The early stages of the blind-loop syndrome may be characterized by delayed protein absorption secondary to blind-loop filling, which is compensated for by the distal gut resulting in an absence of overall protein malabsorption.
 ...
PMID:Protein digestion and absorption in the blind loop syndrome. 51 93

In vitro studies indicate that [(57)Co]cobalamin (Cbl) is preferentially bound to salivary R protein as opposed to intrinsic factor (IF) and that [(57)Co]Cbl bound to R protein is not transferred to IF at either pH 2 or pH 8. Incubation of R protein-[(57)Co]Cbl with pancreatic proteases causes a partial degradation of the R protein moiety and a rapid transfer of [(57)Co]Cbl to IF. We have postulated that the etiology of Cbl malabsorption in pancreatic insufficiency is an inability to partially degrade R protein because of a lack of pancreatic proteases. We have tested this hypothesis by determining the ability of a nonradioactive Cbl analogue, bound with high affinity by R protein but not by IF, to correct the malabsorption of [(57)Co]Cbl in patients with pancreatic insufficiency.R protein bound the Cbl analogue known as cobinamide with affinities that were the same and only 14-fold lower than those for Cbl at pH 8 and pH 2, respectively. Cobinamide was bound by IF with affinities that were 600,000- and 10,000-fold lower than those for Cbl at pH 8 and 2, respectively. The addition of 125 pmol of nonradioactive cobinamide to 0.5 pmol of [(57)Co]Cbl before being added to 1 pmol of R protein and 1 pmol of IF, markedly inhibited the ability of R protein to compete with IF for binding the [(57)Co]Cbl. Similar results were obtained with freshly aspirated gastric juice. This change was essentially indistinguishable from that observed previously when R protein or R protein-[(57)Co]Cbl was incubated in vitro with trypsin. The oral administration of 100 nmol of nonradioactive cobinamide in Schilling tests was equivalent to trypsin in its ability to completely correct the malabsorption of 0.4 nmol of [(57)Co]Cbl in three patients with pancreatic insufficiency. The fact that both trypsin and nonradioactive cobinamide inhibit the ability of R protein to compete with IF for [(57)Co]Cbl binding in vitro, and correct the mal-absorption of [(57)Co]Cbl in patients with pancreatic insufficiency in vivo, supports our hypothesis that the primary defect in Cbl absorption in this disease is an inability to partially degrade R protein because of a lack of pancreatic proteases.
 ...
PMID:Correction of cobalamin malabsorption in pancreatic insufficiency with a cobalamin analogue that binds with high affinity to R protein but not to intrinsic factor. In vivo evidence that a failure to partially degrade R protein is responsible for cobalamin malabsorption in pancreatic insufficiency. 65 18

Malabsorption and diarrhea in hyperthyroidism has been attributed in part to an increased rate of gastrointestinal transit as measured with barium sulfate suspension. Data are unavailable on the effect of hyperthyroidism on gastric emptying rates of normal food and pancreatic enzyme secretion. These functions have been studied in 4 hyperthyroid patients and compared to results obtained when treatment achieved euthyroidism. Pancreatic trypsin secretion was half the euthyroid level in the hyperthyroid state. No significant change in bile salts occurred, although there was a tendency for a greater proportion of dihydroxy bile salts while hyperthyroid. Gastric emptying rates of a mixed fat, protein, and carbohydrate liquid meal were normal. Similarly the gastric emptying rate of a beef stew plus chicken liver meal was normal. We conclude that in hyperthyroidism gastric emptying rates of "physiologically active" food is normal. Pancreatic enzyme secretion is depressed in hyperthyroidism and may contribute to maldigestion.
 ...
PMID:The effect of hyperthyroidism on gastric emptying rates and pancreatic exocrine and biliary secretion in man. 71 57

Enterokinase initiates digestion of protein by conversion of trypsinogen into trypsin. The interactions between enterokinase and trysin were investigated in 6 patients with intractable diarrhea of infancy and 34 children with celiac disease. The six infants between 2 and 3 months with intractable diarrhea of infancy had reduced mucosal enterokinase activity (9.5 +/- 4.8muM per gram of protein per minute) and reduced intraluminal trypsin activity (2.9 +/- 0.7muM per gram of protein per minute) as compared with healthy controls (109 +/- 34.2muM per gram of protein per minute and 14.3 +/- 5.8muM per gram of protein per minute) respectively. The activities of all enzymes returned toward normal following treatment with intravenous alimentation. The mucosal morphology of all pretreatment biopsies in all cases showed Grade III atrophy which improved. These findings suggest that enterokinase deficiency and reduced intraluminal trypsin activity in intractable diarrhea of infancy may be one of the contributing factors to protein malabsorption and consequent malnutrition. Thirty-four children with celiac disease were between the age of 9 months and 13 years. The 11 newly diagnosed patients with celiac disease demonstrated Grade III to IV atrophy of the mucosa. The 23 patients with treated celiac disease on a gluten-free diet showed a normal to Grade II atrophy. In both treated and untreated celiac disease the enterokinase activities and the intraluminal trypsin activity were within normal limits. The enterokinase activity in celiac disease is near normal in contrast to the marked reduction noted in intractable diarrhea of infancy even though the intestinal mucosa shows marked morphological alteration and the disaccharidase activities are greatly reduced in celiac disease. After a prolonged alimentary fast of up to 26 days on intravenous alimentation, two patients with intractable diarrhea of infancy showed improvement in the activities of enterokinase and trypsin. These findings demonstrate that enterokinase and trypsin activities in the gut were present and improved in the absence of oral feeding.
 ...
PMID:The interrelationship of enterokinase and trypsin activities in intractable diarrhea of infancy, celiac disease, and intravenous alimentation. 80 41

Extensive metabolic studies were conducted in five normal controls and in five study patients after total gastric resection with Roux-en-Y (RY) reconstruction to determine the nutritional consequences of this particular technique of restoring gastrointestinal continuity. Although malabsorption of fat (19.2 +/- 2.2%) and nitrogen (22 +/- 2.5%) demonstrated in the study patients was moderate, it was significantly greater than normal ( less than 0.01). In spite of the demonstrated malabsorption, however, positive nitrogen balances (+ 0.33 +/- 0.18 gm/day) were maintained in the RY patients throughout the investigative period. These observations suggest that malabsorption after RY is infrequently of clinical significance, even in this "worst-case" situation characterized by complete removal of gastric tissue. Malnutrition should occur in only those patients with more limited gastric resections and RY reconstruction who are unable to increase caloric intake to cover losses due to malabsorption. A significant decrease in both trypsin and lipase concentrations and a marked delay in secretion of these enzymes was noted in the RY patients in response to a test meal (p less than 0.01). Malabsorption of fat and nitrogen in RY patients improved after exogenous pancreatic enzymes, but not after administration of tetracycline. Bacterial overgrowth as a cause of postoperative malabsorption may be less important than previously thought. Malabsorption after RY is due primarily to maldigestion brought about by duodenal bypass which, in turn, results in either an absolute or a relative pancreatic enzyme insufficiency.
 ...
PMID:Pathophysiology and significance of malabsorption after Roux-en-Y reconstruction. 87 Oct 13

We undertook to test the recent suggestion that measurement of immunoreactive carcinoembryonic antigen (CEA) in pancreatic secretion may be useful in diagnosis of pancreatic cancer. Using duodenal intubation and a perfusion method in 57 cases, we measured the rate of pancreatic CEA secretion into the duodenum under basal saline perfusion, alone and with continuous intravenous infusion of secretin (2 clinical units per kg per hr) and of cholecystokinin-pancreozymin (CCK, 15 Crick-Harper-Raper units per kg per hr); and we compared the CEA output with secretion of trypsin, lipase, and bicarbonate under the same conditions. Subsequent laparotomy revealed pancreatic carcinoma in 25 patients, pancreatitis in 7, other intraabdominal malignancies in 6, and benign nonpancreatic disorders in 19. CEA output rates did not differentiate all pancreatic-cancer patients from other patients in any test condition. However, pancreatic enzyme outputs were abnormal with almost 90% of cancers of the pancreatic head and with 75% of cancers of the pancreatic body and tail. For detection of pancreatic cancer, enzyme and bicarbonate outputs in response to CCK are more accurate than pancreatic CEA or bicarbonate outputs in response to secretin. Since CCK-stimulated enzyme outputs can be related accurately to malabsorption (not reported here), we prefer them to bicarbonate output for assessment of pancreatic function.
 ...
PMID:Prospective evaluation of the pancreatic secretion of immunoreactive carcinoembryonic antigen, enzyme, and bicarbonate in patients suspected of having pancreatic cancer. 89 42

1. Intestinal brush border enzymes have heterogeneous rates of turnover, the largest proteins having the fastest turnover. Since the membrane faces the intestinal lumen, the effects of pancreatic factors were examined in mediating this turnover. Surgical subtotal pancreatectomy was used as an experimental model to study the turnover of brush border proteins in the absence of most pancreatic secretions. 2. Subtotal (95%) pancreatectomy of rats was found to cause elevations by about 50% of total activity and specific activities of certain brush border enzymes (maltase, sucrase, lactase), but not of others (alkaline phosphatase, trehalase). Rats were judged to be functionally deficient in pancreatic proteolytic enzymes (a) by demonstration of vitamin B-12 malabsorption, which was corrected by trypsin, and (b) by the finding of only about 20% of proteolytic activity appearing in the lumen after a test meal when compared to control. 3. To measure protein turnover in vivo the method of double labelling was used, where [3H]- and [14C]valine were administered intraduodenally in sequence 10 h apart. With this technique, a high 3H/14C ratio is correlated with rapid turnover. Proteins with apparent molecular weights of about 200 000-270 000 were found to turn over more rapidly than smaller proteins. 3H/14C ranged from 4.7 to 6.2 in animals without pancreatic insufficiency. In the face of decreased pancreatic proteolysis, the 3H/14C ratio was 2.3-3.1, similar to that of proteins with a slow half life. 4. Estimates of relative synthetic rates of large brush border proteins were lower than normal in pancreatectomized animals, but were constant over the period of the labelling experiment. The high enzyme levels in the face of lower synthetic rates confirms that, at the new steady rate, degradation rates must be slower for large brush border proteins in pancreatic insufficiency. 5. In vitro, using purified brush borders, unfractionated pancreatic enzymes were found to remove sucrase, maltase and lactase, but not alkaline phosphatase and trehalase. The enzyme most potent in this respect was the pancreatic protease, elastase. Non-proteolytic enzymes (amylase, lipase, phospholipase A) were inactive in removing enzyme from the brush border. The addition of elastase to pancreatectomized animals in vivo restored the rapid turnover rate of large brush border proteins. 6. A model is thus proposed for the normal catabolism of some large intestinal brush border proteins. It is suggested that the surface of intestinal absorptive cells is being constantly remodelled, and that certain surface enzymes are in part removed from the membrane by the action of pancreatic proteases. A possible special role for elastase is suggested.
 ...
PMID:The possible role of pancreatic proteases in the turnover of intestinal brush border proteins. 114 88

A 1.5-year-old girl was admitted with chronic diarrhea of 10 months duration and retarded physical and psychomotor development. Duodenal tryptic activity was absent on testing with secretin and cholecystokinin. With pancreatic enzyme replacement diarrhea ceased and growth recommenced. Duodenal tryptic activity returned to normal within 6 months. A 10-year follow-up revealed normal physical and mental growth. Secondary deficiency of trypsin is a rare cause of malabsorption in childhood; correct and timely treatment can avoid severe, irreversible developmental defects.
 ...
PMID:[Malabsorption and developmental retardation due to secondary trypsin deficiency]. 168 66

A 10-year-old mentally retarded girl was sent to our hospital due to generalized edema, vomiting and poor appetite for several days. Serum albumin level was low, but no proteinuria was detected. Her stool was bulky and foul. Stool examination for parasite with formalin-ether concentration method revealed negative result. Trypsin activity test of stool revealed low trypsin activity as compared with normal specimen. Daily fecal fat exceeded upper normal limit. The diagnosis of giardiasis was confirmed by duodenal juice examination. Intestinal histology revealed mild shortening of the villi with increased mononuclear cell infiltration in the lamina propria. The daily stool amount decreased markedly after treatment with metronidazole 250 mg three times a day for 7 days. The edema subsided during the treatment. Serum albumin bevel returned to normal after the treatment. Giardiasis with malabsorption syndrome has often been overlooked in Taiwan. It is advised that in case of malabsorption syndrome giardiasis should be included in the list of differential diagnosis.
 ...
PMID:[Giardiasis with malabsorption syndrome: report of one case]. 227 67

The effect of high fiber diet on fat malabsorption was evaluated in twelve patients with exocrine pancreatic insufficiency secondary to chronic alcoholic pancreatitis. Additionally, the effect of dietary fiber on pancreatic enzymes was examined in vitro, employing different concentrations of cellulose, pectin, and wheat bran incubated with amylase, lipase, and trypsin. Ingestion of a high fiber diet was associated with a small but significant (p less than 0.01) increase in fecal weight and fecal fat excretion. All patients complained of increased abdominal flatulence with high fiber diet, however, no significant increase in frequency of bowel movements was noted. In vitro studies demonstrated reduction in pancreatic enzyme activity by increasing concentration of dietary fiber and its components. These data suggest that steatorrhea may be enhanced with the ingestion of high fiber diet in patients with exocrine pancreatic insufficiency on oral pancreatic enzyme therapy. Increase in fecal fat excretion may, in part, be related to reduction in the activity of pancreatic enzymes by the dietary fiber.
 ...
PMID:Dietary fiber in pancreatic disease: effect of high fiber diet on fat malabsorption in pancreatic insufficiency and in vitro study of the interaction of dietary fiber with pancreatic enzymes. 257 39


<< Previous 1 2 3 4 5 6 Next >>