Initial Emptying Research Articles

Effects of nutrients on gastrointestinal motility and gastric emptying after distal gastrectomy with Roux-Y gastrojejunostomy in dogs.

The aim of the study was to clarify whether nutrients are still capable of slowing gastric emptying following Roux-Y gastrectomy, as in normal dogs. Gastrointestinal motility and gastric emptying of acaloric and nutritive meals with different viscosities were measured in normal dogs and after a two-thirds Roux-Y gastrectomy. In gastrectomized dogs low-viscosity nutritive meals emptied unduly rapidly in an initial phase, although the frequency and spread of contractions, ie, the propulsive activity of the jejunal Roux limb were diminished. A slow emptying rate during the following period was due to a long-lasting inhibition of gastric and jejunal motility. Medium-viscosity nutritive meals emptied in gastrectomized dogs as slowly as in normal animals, but this effect was primarily caused by the meal viscosity and only secondarily by the nutrients. It is concluded that following Roux-Y gastrectomy a regulation of gastric emptying is preserved; however, the onset of an effective control is delayed, resulting in a rapid initial emptying of low-viscosity meals.

Stomach Emptying of Milk Diets in Pigs. A Mathematical Model Allowing Description and Comparison of the Emptying Pattern

The effect of doubling the nutrient intake in pigs fed a liquid cow's milk diet was investigated. This was done, either by doubling the volume given, or by doubling the dry matter content of the milk. There were two experiments in which the cumulative outflow of fresh contents, dry matter, crude protein and total carbohydrates, relative to the intake, was studied as affected by the treatments. This was done using pigs equipped with a simple duodenal cannula and an occluding balloon. The cumulative outflow curves indicated that the emptying process was biphasic both for the fresh contents and the nutrients emptied. A rapid emptying, followed by a period during which the emptying was inhibited was seen during the first emptying phase, the so called initial emptying. Thereafter the emptying was resumed again during the second phase: the final emptying. The individual emptying patterns were described very accurately by an adapted mathematical function with four parameters: y = c (1-2-(at)b)+dt3. The parameters c, b and a describe the initial emptying which is intrinsically exponential while d is descriptive for the final emptying. The appearance of the outflowing material, changing with time from unchanged milk, whey plus clot fragments, pure whey to whey with granular clot fragments indicated that the clotting of the milk was complete after about 15 min. The clotting certainly was responsible for the biphasic appearance of the emptying pattern. The emptying pattern of fresh contents was not related to the emptying pattern of dry matter and nutrients. Due to the rather high variability, there were no significant differences between the emptying patterns of dry matter and nutrients studied, although there were clear indications that crude protein was emptied at a slower rate than the other nutrients. Doubling the nutrient intake either by doubling the volume given, or by doubling the dry matter content of the milk did not change the initial emptying pattern to a great extent, except in the first experiment, where doubling the volume increased the relative amount of dry matter and nutrients emptied. A difference of gastric capacity related to a difference in age between the pigs used in the two experiments is thought to be the reason for this discrepancy. The relative amounts of dry matter and nutrients emptied during the final emptying phase on the other hand were inversily related to the amount of nutrients given.(ABSTRACT TRUNCATED AT 400 WORDS)

A model for receptor-regulated calcium entry

A model is proposed for the mechanism by which activation of surface membrane receptors causes sustained Ca 2+ entry into cells from the extracellular space. Reassessment of previously published findings on the behavior of receptor-regulated intracellular Ca 2+ pools leads to the conclusion that when such pools are empty, a pathway from the extracellular space to the pool is opened; conversely when the pool is filled, the pathway is closed and it becomes relatively stable to depletion by low Ca 2+ media or chelating agents. The biphasic nature of agonist-activated Ca 2+-mobilization is thus seen as an initial emptying of the intracellular Ca 2+ pool by inositol (1,4,5) trisphosphate, followed by rapid entry of Ca 2+ into the pool and, in the continued presence of inositol (1,4,5) trisphosphate, into the cytosol. On withdrawal of agonist, inositol (1,4,5) trisphosphate is then rapidly degraded, the pathway from the pool to the cytosol is closed, and rapid entry from the outside continues until the Ca 2+ content of the pool reaches a level that inactivates Ca 2+ entry. This capacitative model allows for Ca 2+ release and Ca 2+ entry to be controlled by a single messenger, inositol (1,4,5) trisphosphate.

Gastric emptying of solids in man.

The influence of the type and size of solid particles on their emptying from the stomach was studied using isotopically labelled chicken liver and inert particles in normal subjects and in patients who had undergone gastric surgery. In normal subjects, initial emptying of the liver was slower than that of inert particles both for large liver cubes (1 cm) and small cubes (0.3 cm). Liver emptying subsequently accelerated to be faster than emptying of the inert particles. Overall emptying of the liver given as small cubes was faster than large cubes; 50% emptied in 50 minutes and 70 minutes respectively. In the postoperative subjects, emptying of the liver and of the inert particles was identical. The findings are consistent with the hypothesis that solid foods such as liver are ground down and 'liquified' by the action of gastric peristalsis before being discharged to the duodenum. Ingested particle size appears to influence the rapidity of this process, which should be distinguished from the propulsive function of the stomach where small solid particles are concerned.

Different gastric, pancreatic, and biliary responses to solid-liquid or homogenized meals

We have compared responses to an ordinary solid-liquid (S) meal and to a homogenized (H) meal of identical composition (sirloin steak, bread, butter, ice cream with chocolate syrup, and water) by measuring simultaneously postprandial gastric, pancreatic, and biliary functions by marker-perfusion techniques. Responses to each (S or H) meals differed strikingly both in magnitude and pattern. S meals elicited a stronger early gastric secretory response (acid, pepsin, and volume) which compensated for faster initial emptying and resulted in higher gastric acidity and volume than after H meals. Further, nutrients ingested with S meals were emptied at a slower rate than H (as evidenced by a more gradual decline in intragastric buffer and osmolality, as well as time required for complete emptying of the meal). This, in turn, prolonged pancreatic and biliary responses since stimulation of these organs continued for as long as meal was delivered into the duodenum. However, early biliary outputs (gallbladder response) were less after S than H, probably because nutrients entered the duodenum more slowly and were initially diluted by rapidly emptying water. The physical characteristics of each meal (encompassing appearance, taste, and form of ingestion) probably accounted for early differences in digestive responses. Later, interactions between gastric (motor and secretory), pancreatic, and biliary functions played a major role. Our findings suggest that gastric, pancreatic, and biliary responses to liquid test meals introduced into the stomach may differ substantially from the presumably more physiological response to ordinary solid-liquid meals.

Gastric emptying of a liquid meal in health and duodenal ulcer disease.

In the present investigation an extension of the method of George was used, which allows the rate of emptying of the gastric content (GC) to be assessed. The aim of the study was to find out whether ther is any difference in gastric emptying rate of a liquid meal of 750 ml 10% glucose (glucose monohydrate, mol. wt. 198) between healthy subjects and duodenal ulcer patients (DU). The straight numerical volume of GC, the logarithm and the square root of GC were related to time, and these functions were compared. The correlation coefficient for the regression line for these functions showed that data both for healthy subjects and DU gave a better fit to the GC/time and GC/relationship than to a semi-logarithmic function, when the starting point at time zero was excluded. Regardless of the type of transformation of the basic data, there was no difference between healthy controls and DU as regards the regression coefficient, indicating that from 20 min after the installation of the test volume the GC is decreasing at the same rate in the two groups. When the straight numerical volume of GC was used, there was a significant difference in the extrapolated Y-intercept for the regression lines between healthy subjects and the DU, indicating an increased initial emptying in the DU patients. This was further confirmed when the volume emptied during consecutive 20-min periods was estimated. Furthermore, there was a shorter emptying time in patients with duodenal ulcer than in healthy controls.

Evidence for a time delay between prolactin release and the resulting rise in milk secretion rate in the rat.

SUMMARY The mammary glands of rats either maintained continuously in the animal room on day 14 post partum or isolated in a room without other rats on day 21 post partum, refilled only partially within 8 h after the pups had withdrawn the milk from the glands by suckling with the aid of oxytocin injections to the mother. The partial refilling occurred regardless of whether or not the release of prolactin at the time of suckling was blocked by an injection of an extract of stalk median eminence (SME). The mammary glands of rats not injected with SME continued to refill and reached near capacity within 16 h whereas those of the SME-injected rats failed to refill any further. The glands of the SME-injected rats could be stimulated to refill more completely within 8 h after the initial emptying provided prolactin either was injected or was released endogenously by exposing the mothers to exteroceptive signals from their pups midway during the 8-h period of non-suckling which preceded the initial emptying. More complete mammary refilling also occurred within 8 h if a 4-h rather than an 8-h period of non-suckling preceded the initial emptying of the glands. The results of these investigations indicate that the prolactin released by suckling at the time of the initial emptying of the glands influenced only that milk which reaccumulated in the emptied glands during the 8th—16th h following suckling. The milk which reaccumulated during the first 8 h appeared to be influenced by prolactin released several hours before suckling. The results suggest, therefore, that a time delay of several hours exists from the time of release of prolactin by suckling until the full stimulatory effect of the hormone upon milk secretion is manifest. Thus the milk secreted after emptying of the glands at a given suckling would be the result of prolactin released earlier either at previous sucklings or in response to exteroceptive stimulation.

Effect of suckling and of exteroceptive stimulation upon prolactin release in the rat during late lactation.

SUMMARY The results of experiments in which the prolactin in the primiparous rat pituitary was bioassayed suggested that the failure of suckling to release prolactin after 8 h of non-suckling on day 21 post-partum was due to the fact that prolactin had been discharged from the pituitary during the 8-h non-suckling period, presumably by exteroceptive signals emanating from the general environment of the animal room. This was substantiated in other experiments in which prolactin release was assessed indirectly through its stimulatory effects upon milk secretion. In these experiments, the mammary glands of rats maintained continuously in the animal room filled faster on day 21 after complete emptying of the glands by exogenous oxytocin, than did either rats on day 14 post-partum maintained continuously in the animal room or rats isolated in a room without other rats on day 21 post-partum. The glands of the latter two groups of rats could be stimulated to fill faster provided prolactin was injected 4 h before the initial emptying of the glands. The exteroceptive stimuli in the animal room environment that stimulated the release of prolactin in the 21-day post-partum rat apparently emanated at least in part from other lactating rats and/or their litters, since faster mammary gland refilling occurred in isolated 21 day post-partum rats when they were exposed to the presence of lactating rats with their litters for 30 min halfway through the 8-h non-suckling period which preceded the initial emptying of the gland. Exposure to male rats, on the other hand, was totally ineffective. A release of prolactin occurred in response to animal room environmental stimuli in the day 14 primiparous rat provided 13–14 day old foster pups were inserted in place of the mother's own pups on day 7. Thus, the rapidly changing characteristics of the pups from 14 to 21 days of age in some manner is involved in the increasing responsiveness of the exteroceptive mechanism for prolactin release which occurs from day 14 to day 21 post-partum.

Gastric emptying after vagotomy and pyloroplasty. Relation to some postoperative sequelae.

Emptying of liquids from the stomach was studied in 19 patients who had had a vagotomy and pyloroplasty and the results compared with 12 patients with duodenal ulcers and 9 patients with normal upper gastrointestinal tracts. The patterns of gastric emptying after vagotomy and pyloroplasty was found to consist of a very rapid initial emptying phase followed by emptying at a rate rather faster than in the other two groups. There was no difference in the gastric emptying of patients with duodenal ulcer and those with a normal gastrointestinal tract. Patients who complained of postprandial fullness and dumping after vagotomy and pyloroplasty had extremely rapid initial gastric emptying, more than half the test solution leaving the stomach almost immediately. Three patients who had postoperative gastric ulcers, 2 patients with vomiting since operation and 1 with postvagotomy persistent diarrhea showed a starting index and half-life similar to those of asymptomatic postoperative patients and only minor differences in the emptying time.

Alterations in Muscular and Electrical Activity of the Stomach Following Vagotomy

IN 1943, Dragstedt and Owens¹introduced bilateral section of the vagus nerves as a therapeutic procedure for treatment of duodenal ulcer. Since that time, this operation with modifications has become firmly established as the procedure of choice in the surgical treatment of duodenal ulcer. Bilateral vagotomy not only eliminated the cephalic phase of gastric secretion, thus providing therapeutic benefit to the duodenal ulcer patient, but also abolished the cephalic phase of gastric motor activity. At the time vagotomy was introduced as a therapeutic procedure a wide difference of opinion existed about the long-term effect of bilateral vagal section on gastric motor behavior. The work of McCrea et al²indicated that there was a more rapid initial emptying time of the stomach following vagal section but that the total emptying time was essentially unchanged. Meek and Herrin's³series of experiments indicated that the consistency of the meal was

Initial Emptying Time of Stomach in Primigravidae as Related to Evacuation of Biliary Tract.

Previous studies1 have shown that in the second and third trimesters of pregnancy the gall bladder of 13 gravida discharged an average of only 49% of contents (within 40 minutes after a standard meal of egg-yolk) as compared with an average discharge of 73% obtained from 12 nulligravidae; that the best 8 of the 13 discharged an average of only 57% and the remaining 5 an average of only 38%; but when the latter were tested 6 to 8 weeks postpartum, the amount of bile discharged in the 40-minute period (71%) approximated the nulligravid figure.The present study has attempted to ascertain whether this retardation in rate of emptying of the gall bladder in pregnancy could have been due to a delay in the initial rate of emptying of the stomach. To this end 17 nulligravidae (nursing students) were examined fluoroscopically after receiving a 7 standard meal of egg-yolk to which 3 heaping teaspoons of barium sulphate had been added. They were then used as controls for 18 primigravidae of the second and third trime...