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This work was designed to investigate the site of oxalate hyperabsorption in malabsorption syndromes. 1) Urinary oxalate excretion was measured in 27 patients with ileal resection (IR) and steatorrhea. Mean urinary oxalate excretion was high in 13 patients with IR and intact colon and in 9 subjects with IR and right hemicolectomy (90.2 +/- 11.9 and 108 +/- 18.6 mg per 24 hours; mean +/- S.E.M.), whereas it was normal in 5 patients with IR and ileostomy (21.9 +/- 4.4 mg per 24 hours). Steatorrhea was similar in the three groups. 2) On one patient of the last group in whom the colon had not been removed initially but excluded closure of the ileostomy resulted in the development of frank hyperoxaluria. 3) Intracolonic perfusion of calcium (1.93 g per day) abolished or greatly reduced the hyperoxaluria in 3 patients. These results indicate that the colon is the major site of oxalate hyperabsorption, and the right colon is not necessary for the development of hyperoxaluria in malabsorption syndromes.

We have measured, by an intubation method, gastric evacuation and gastrointestinal absorption of alcohol ingested with a meal in seven healthy nonalcoholic subjects. A homogenized meal containing [14C]PEG and ethanol (1 g/kg body wt) was given intragastrically while saline containing [57CO]vitamin B12 was perfused into the duodenum. Of the ingested alcohol, 39.4 +/- 4.1% was absorbed through the stomach wall during the first postprandial hour and 73.2 +/- 4.2% during the total postcibal period, whereas only 24 +/- 3% was absorbed during the same time in the duodenum. Thus alcohol ingested with a meal is mainly and rapidly absorbed in the stomach; the contribution of the small intestine below the angle of Treitz to alcohol absorption is negligible.

The effect of the presence of food in the intestinal lumen on fluid transport by an intestinal loop isolated from nutrients is debatable and seems to be species dependent. The aim of the present study was to investigate this effect in humans. Fluid and ion transport by a 30-cm-long jejunal loop was measured by the perfusion of a plasmalike electrolyte solution below an occlusive balloon inflated at the angle of Treitz. At the same time, the duodenum was infused at the papilla by saline (control period) or one of the following solutions (test period): protein hydrolysate, starch hydrolysate, lipids, or mixed nutrients. The four solutions (pH 7; 300 mosmol/L; 540 kcal/L) were infused in 6 normal subjects in a randomized order. In 6 further subjects, two other loads of intraduodenal lipids (120 and 1080 kcal/L) were tested according to a similar protocol. Blood samples were taken serially for radioimmunoassays of gastrin, secretin, cholecystokinin, pancreatic polypeptide, gastric inhibitory polypeptide, vasoactive intestinal polypeptide, motilin, and somatostatin. Intraduodenal mixed nutrients, proteins, and lipids significantly reduced water and ion jejunal net absorption or induced a net secretion (without dose-effect relationship for lipids) and stimulated plasma cholecystokinin, pancreatic polypeptide, and gastric inhibitory polypeptide. Intraduodenal lipids also stimulated circulating levels of gastrin and vasoactive intestinal polypeptide. Intraduodenal sugars did not change jejunal fluid and ion transport and significantly increased plasma gastric inhibitory polypeptide. Covariance analysis showed transjejunal fluid movements to be linked with plasma levels of cholecystokinin. We conclude that an intraduodenal mixed meal exerts a secretory effect on a jejunal loop isolated from the nutrients and that this effect is due to the lipid and protein content of the meal; our data are compatible with a mediation of this phenomenon by cholecystokinin.

Although abdominal complaints are frequent in both acute and chronic alcoholism, little is known of the effect of ingestion of ethanol with a meal on the function of the upper digestive tract. We have studied the effects of oral ethanol (1 g/kg body wt) taken with food on the gastric emptying rate of a solid-liquid meal as measured by a dual radioisotope technique in six normal subjects; and the gastric response (emptying and secretion), biliopancreatic secretions, and duodenal nutrient absorption after an homogenized meal, as evaluated by a gastroduodenal intubation-marker perfusion technique on seven healthy volunteers. In the latter experiments, radioimmunoassays of gastrin, secretin, cholecystokinin, pancreatic polypeptide, motilin, somatostatin, gastric inhibitory polypeptide, and vasoactive intestinal polypeptide were performed serially. As compared with the control experiment, alcohol induced the following effects: marked delay of gastric emptying of solids, smaller slowing effect on gastric emptying of the liquid phase of the solid-liquid meal and of the homogenized meal; no significant change in gastric acid secretion; no change in the overall postprandial pancreatic enzyme outputs, but a delay of lipase secretion; no change in the early bile salt postprandial output, but a reduced bile salt secretion from the second postprandial hour onwards; no significant change in carbohydrate and lipid duodenal absorption; and a significantly greater postcibal gastrin release. The mechanisms for these effects of alcohol on upper digestive tract function remain to be clarified.

Because of its simplicity, a tube with a proximal occlusive balloon is widely used to measure segmental intestinal absorption in man. Yet, the possibility that the presence of an inflated balloon might alter the absorptive capacity of the underlying segment of intestine has never been tested. In the present work the jejunal absorption of water and ions has been measured in 13 healthy subjects with the proximally occlusive tube and with the triple lumen nonocclusive method; precautions were taken to achieve similar flow rate and ionic composition of the fluid entering the test segment with both techniques in each subject. Under these conditions net water and ion movements measured by the two methods were identical. This finding validates the use of the proximal occlusive tube to measure intestinal absorption in man.

In 11 conscious volunteers, the jejunal absorption was measured during basal state and during the simultaneous intravenous infusion of small doses of gastrin, secretin, cholecystokinin, glucagon and gastric inhibitory polypeptide. The blood levels of gastrin, secretin, glucagon, and GIP were measured by RIA and were close to those achieved after a meal. The basal net absorption of water and electrolytes was reversed to a net secretion during the hormonal infusion. These results suggest that the jejunal secretion observed after a meal in man may be mediated by hormones released by the meal.

A perfusion technique with a proximal occluding balloon has been used to study the absorption of glucose, sodium, and water from the human jejunum at different rates of flow. The absorption of glucose and water was significantly higher with the balloon deflated than inflated, probably because of reflux of infused solution above the point of infusion. Above the inflated balloon 0 to 4.2 ml/min of endogenous secretions could be recovered. Increasing flow rates increase the glucose absorption rate; a single relationship could be found between the glucose load and glucose absorption rate, and single values for the maximum velocity and for the half saturating load were calculated whatever the infusing rate and the initial glucose concentration. The stimulating effect of glucose on water and sodium movement increases gradually when the initial sugar concentration varies from 14 to 133 mM/1. Above this concentration a drop in water and sodium movement is observed, although the initial sodium concentration is kept constant. High flow rates result in a decrease of water absorption and an increase in sodium and potassium secretion rates.