In this study the early phase of the morphological adaptation of rat ileum after a proximal resection of 60% has been studied using microdissection and cell labelling techniques. Resected rats and sham-operated controls were killed 2, 4, 6, 10 and 12 days after surgery. Intraperitoneal injections of 3H-thymidine were carried out 24 or 12 h prior to sacrifice. In the latter groups mitotic arrest was achieved by vincristine. A stereo-microscope was used to measure and calculate the following parameters: intestinal diameter; villus: height, width, breadth at base and apex, surface, enterocytes per 100 micrometers length, cell pool, number of villi and absorptive surface per mm2 serosal area; crypt: length, enteroblasts per 100 micrometers length and per column, cell columns and mitoses per crypt, cell pool, crypts, and mitoses per unit serosal area; cell kinetics: migration rate, villus transit time. To test the influence of treatments, postoperative time course and the location of the intestinal segment and their possible interactions, factorial analyses of variance were carried out on the parameters investigated. The main findings, demonstrated for the first time, were: 1. An increase in the villus surface which was achieved by proportional enlargement of villus geometry; 2. This increase in the villus surface led to an enlarged absorptive surface per unit serosal area; 3. A reduction of villus transit time of the individual enterocyte; 4. A most pronounced magnitude of adaptative response in the proximal remnants which was gradually diminished in aboral direction, and 5. A sequential course of adaptative response of the various crypt parameters investigated.

Evidence from animal experiments suggests that intraduodenal infusion of nutrients leads to an inhibition of gastric acid secretion via an enterogastric feedback mechanism. Detailed data are lacking, however, on the difference in circadian gastric acidity between gastric and intraduodenal alimentation in man. We conducted a randomized study in 10 healthy volunteers (5 men, 5 women, age 22-30 yr). From 8:00 am of the first study day until 4:00 pm of the next day, either a standardized normal meal or a liquid polymer diet (Fresubin) was given orally at 8:00 am, noon, and 6:00 pm. In a third experiment, a liquid hydrolysed diet (Survimed OPD) was continuously applied to the duodenum using a portable pump. Daily caloric intake and main nutrient components were comparable in all three diets. From 2:00 pm of the first day until 4:00 pm of the next day, an intragastric pH-metry was performed with a combined glass pH-electrode in the gastric corpus. Median pH-values from predefined time periods (whole day, prandial, interdigestive, nocturnal) were compared between the three groups. The orally applied liquid polymer diet led to a significantly stronger increase in 24-hr and prandial gastric pH than the normal diet. Twenty-four-hr, interdigestive, and nocturnal pH-median values were significantly higher during continuous intraduodenal application of the liquid hydrolysed diet than during the normal diet.

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