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PubMed1996

Rat stomach enterochromaffin-like cells are not stimulated by pylorus ligation. A biochemical and ultrastructural study.

BACKGROUND: The enterochromaffin-like (ECL) cells in the rat oxyntic mucosa produce histamine and contain cytoplasmic granules, microvesicles, and secretory vesicles. The cells respond to gastrin by the release of histamine (associated with loss of secretory vesicles), which is thought to mediate the gastrin-induced stimulation of the parietal cells. Gastric acid secretion is stimulated also by vagal excitation, which can be induced, for instance, by pylorus ligation. The present study addresses the question whether the ECL cells are involved in the acid response to pylorus ligation. METHODS: Rats were subjected to pylorus ligation and killed 4 or 16 h later. Other rats were subjected to sham operation (laparotomy). Some of the rats received human Leu15-gastrin-17 (5 nmol/kg/h) by intravenous infusion for 30 or 60 min before being killed. The serum gastrin concentration, the oxyntic mucosal histidine decarboxylase (HDC) activity, HDC mRNA concentration, histamine concentration, and gastric acid output were measured. Specimens from the oxyntic mucosa were processed for transmission electron microscopy. Electron micrographs of ECL cells were analyzed planimetrically. RESULTS: The gastric acid output was high, but the serum gastrin concentration was not affected by the pylorus ligation. The HDC activity and the level of HDC mRNA in the oxyntic mucosa were reduced, but the histamine concentration was unchanged. The secretory vesicles and granules of the ECL cells were unaffected, whereas the number and volume density of the microvesicles were reduced. Gastrin administration to sham-operated and pylorus-ligated rats lowered the oxyntic mucosal histamine concentration and increased the HDC activity in both groups. CONCLUSIONS: ECL cells in the rat stomach do not mediate the gastric acid response to pylorus ligation, and ECL cells in the pylorus-ligated stomach retain their ability to respond to gastrin with activation.

Animals↗
PubMedDate not supplied

Postoperative clinical evaluation following pylorus-preserving gastrectomy.

BACKGROUND/AIMS: Recent pathological study demonstrated that extended lymphadenectomy is not always necessary for patients with early gastric cancer. METHODOLOGY: Twenty-eight patients underwent pylorus-preserving gastrectomy. The clinicopathological findings of patients with pylorus-preserving gastrectomy were compared to those of 58 patients with conventional distal gastrectomy. RESULTS: There were no significant differences in surgical duration, blood loss, blood chemistry, food intake, and body weight loss. Regarding abdominal symptoms, early dumping syndrome was significantly higher in distal gastrectomy than in pylorus-preserving gastrectomy (35.6% vs. 12.0%, p<0.05). Remnant gastritis was also significantly higher in distal gastrectomy (57.1% vs. 27.7%, p<0.05). However, food residue tended to be more frequently seen in pylorus-preserving gastrectomy (33.3% vs. 61.1%, p=0.052). Based on questionnaire results, the rate of patient satisfaction with their surgical outcome tended to be lower in pylorus-preserving gastrectomy than in distal gastrectomy (84.0% vs. 95.6%, p=0.098). The tendency was more pronounced in patients over 70 years old (77.8% vs. 100%, p=0.065). CONCLUSIONS: Pylorus-preserving gastrectomy is superior to conventional distal gastrectomy in the prevention of dumping syndrome and reflux gastritis. However, since delayed emptying is frequently seen post pylorus-preserving gastrectomy, this procedure is not recommended for older patients under simplistic indications.

Female↗
PubMed1966

The mechanism of the inhibition of gastric secretion produced by esophageal ligation in the pylorus-ligated rat.

Esophageal ligation in the pylorus-ligated rat significantly inhibited volume, titratable acidity, and titratable acid output and reduced the incidence of ulcers, perforations, and death of 18-hr pylorus-ligated rats. Draining the saliva outside the body of the rat by esophageal cannulation produced a significant increase in volume and gastric acidity over the esophagus-ligated preparation. A method for collection of saliva in the unanesthetized unstimulated rat was developed, and basal salivary flow was found to be 0.84 ml/4 hr. Administration of 1.0 ml of freshly collected saliva to esophagus + pylorus-ligated rats increased titratable acidity, but not volume of secretion, to the level found in the pylorus-ligated rat. A similar effect was obtained with administration of 1.0 ml of a phosphate buffer. Removal of the salivary glands had no significant effect on gastric acidity in the pylorus-ligated rat and the reduction in volume could be accounted for by the lack of saliva. Gastric secretion in the esophagus + pylorus-ligated rat was stimulated by histamine, carbachol, insulin, and 2-deoxyglucose. When the vagus nerves were cut, stimulation was still obtained with carbachol but not with insulin or 2-deoxyglucose. The data indicated that rat saliva did not contain a specific gastric stimulant material, and esophageal ligation depressed gastric secretion in the pylorus-ligated rat by inhibition of the central vagal activity.

Animals↗
PubMedDate not supplied

Comparison of quality of life after pylorus-preserving pancreatoduodenectomy and Whipple resection.

BACKGROUND/AIMS: There have been many supportive data that the postoperative changes in nutritional status are more favorable after pylorus-preserving pancreatoduodenectomy than after Whipple resection; however, few reports are available on the postoperative changes in subjective quality of life after pancreatoduodenectomy. The aim of this study was to compare the postoperative change in quality of life after pylorus-preserving pancreatoduodenectomy and Whipple resection. METHODOLOGY: A total of 36 patients (31 with pylorus-preserving pancreatoduodenectomy and five with Whipple resection) were studied regarding quality of life before and at short term (within two months) and at long term (six months to one year) after surgery, using a questionnaire. The questionnaire consisted of 13 physical and 10 psychosocial items. The medical records were also reviewed to evaluate their objective nutritional status. Postoperative changes in quality of life and nutritional status were compared between the pylorus-preserving pancreatoduodenectomy and Whipple groups. RESULTS: Overall and physical quality of life scores dropped at short term and then recovered at long term in the pylorus-preserving pancreatoduodenectomy group, but showed a persistently low value even at long term in the Whipple group. The change in physical quality of life showed almost parallel changes with the nutritional status in both groups. However, the scores of psychosocial quality of life, which reflected the patient's mental status, remained low even at long term in both pylorus-preserving pancreatoduodenectomy and Whipple groups. CONCLUSIONS: Quality of life is more favorable after pylorus-preserving pancreatoduodenectomy than after Whipple resection, but long-standing mental health care is necessary in patients with pyloruspreserving pancreatoduodenectomy and Whipple resection.

Activities of Daily Living↗
PubMed1986

Pancreatoduodenectomy with pylorus preservation for adenocarcinoma of the head of the pancreas.

For many years, the classical Whipple procedure has been the standard operative treatment for resectable periampullary cancer. Recently, the pylorus preservation operation has also been applied to periampullary tumours. This newer procedure has potential advantages in terms of ease of performance and postoperative physiology, but has yet to be proved as an adequate cancer operation. We, therefore, undertook the present retrospective analysis to compare the outcome following the pylorus preservation operation (n = 13) with that of the classical Whipple resection (n = 13) in 26 patients with histologically proved adenocarcinoma of the head of the pancreas. The two groups of patients were comparable for age, sex, pre-operative laboratory data, and resected margins free from tumour. More patients undergoing the classical Whipple resection had Stage I disease (10 versus 4, P less than 0.05). However, this difference would not be significant if the two patients in the pylorus preservation group with carcinomas in situ were considered to have stage I disease. Mean tumour diameter in the pylorus preservation patient group (3.2 +/- 0.6 cm) was smaller (P less than 0.05) than in the classical Whipple group (4.1 +/- 1.0 cm) but more patients in the pylorus preservation group also had metastases to the regional lymph nodes (54 versus 23 per cent). Overall operative morbidity (31 per cent) and mortality (4 per cent) was acceptable and did not differ between the two groups. Five year actuarial survival for pylorus preservation (25 per cent) was comparable to that observed for the Whipple procedure in this and other series.

Adenocarcinoma↗
PubMed2005

Randomized clinical trial of pylorus-preserving duodenopancreatectomy versus classical Whipple resection-long term results.

BACKGROUND: It is not known whether pylorus-preserving duodenopancreatectomy is as effective as the classical Whipple procedure in the resection of pancreatic and periampullary tumours. A prospective randomized trial was undertaken to compare the results of the two procedures. METHODS: Clinical data, histological findings, short-term results, survival and quality of life of all patients having surgery for suspected pancreatic or periampullary cancer between June 1996 and September 2001 were analysed. RESULTS: Two hundred and fourteen patients were randomized to undergo either a standard or a pylorus-preserving Whipple resection. After exclusion of 84 patients on the basis of intraoperative findings, 130 patients (66 standard Whipple operation and 64 pylorus-preserving resection) were entered into the trial. Of these, 110 patients with proven adenocarcinoma (57 standard Whipple and 53 pylorus-preserving resection) were analysed for long-term survival and quality of life. There was no difference in perioperative morbidity. Long-term survival, quality of life and weight gain were identical after a median follow-up of 63.1 (range 4-93) months. At 6 months, capacity to work was better after the pylorus-preserving procedure (77 versus 56 per cent; P = 0.019). CONCLUSION: Both procedures were equally effective for the treatment of pancreatic and periampullary cancer. Pylorus-preserving Whipple resection offers some minor advantages in the early postoperative period, but not in the long term.

Adult↗
PubMed1988

Gastric diversion or pylorus ligation for gastric mucosal integrity and acid secretion studies in the rat?

The advantages of gastric diversion over pylorus ligation in rat gastric mucosal integrity and acid secretion studies over 6 hr were investigated. Mucosal injury developed in 80% of pylorus-ligation controls. Atropine (5 mg/kg) or cimetidine (40 mg/kg) had no effect on this injury (2.9 mm2 +/- 0.9 and 2.8 mm2 +/- 0.7, respectively, vs 3.1 mm2 +/- 1, mean +/- SEM, N = 10); however vagotomy increased it (13.7 mm2 +/- 1.5, mean +/- SEM, N = 10, P less than 0.001). Gastric diversion produced no mucosal injury. Pylorus-ligation H+ output was higher than that of gastric diversion (390.5 mumol +/- 54.8 vs 61 mumol +/- 2.5, mean +/- SEM, N = 10, P less than 0.001). Cimetidine (40 mg/kg) depressed H+ output of gastric diversion (21.3 mumol +/- 1.2 vs 61 mumol +/- 2.5, mean +/- SEM, N = 10, P less than 0.001), but not of pylorus ligation (424 mumol +/- 74.2 vs 390.5 mumol +/- 54.8, mean +/- SEM, N = 10). Vagotomy or atropine depressed pylorus-ligation H+ output (P less than 0.001), but each allowed an output (36.6 mumol +/- 5.5 and 120 mumol +/- 29, respectively, mean +/- SEM, N = 10) significantly (P less than 0.001) higher than that associated with it in gastric diversion (16 mumol +/- 1.4 and 17.1 mumol +/- 1.6, respectively, mean +/- SEM, N = 10). This study demonstrates that in the rat pylorus ligation, in contrast to gastric diversion, injures the gastric mucosa, stimulates H+ secretion, and overshadows the efficacy of antisecretory agents.

Animals↗
PubMed2005

Effects and mechanism of changes of local neurotransmitters in rats' pylorus and bile reflux to the stomach with stress ulcer.

Stress ulcer occurs primarily in severe conditions, with a high incidence and mortality in intensive care units. However, studies on the association between stress ulcer and bile reflux to the stomach with stress ulcer are still inconclusive. Therefore, our research aimed to determine whether or not bile reflux exists during stress ulcer and then to investigate the effects and mechanism of changes of pyloric local neurotransmitters on bile reflux in such circumstances so as to provide a new pathway for clinical intervention. Cold water immersion was used to copy the stress ulcer model of rats. Sixty-five adult Sprague-Dawley rats of either sex were randomly divided into three groups: the normal control group (n = 10), the stress group (n = 30), and the antagonist group (n = 25). The gastric ulcer index, pH, and bile acid of gastric juice were measured before and after stress. Radio Immunoassay Detection Kit and Biochemic Detection Kit were used to measure local contents of CGRP (calcitonin gene-related peptide) and nitric oxide, respectively, in rats' pylorus. The local contents of nitric oxide in rats' pylorus reached a maximum at 1 hr after stress. The bile acid and pH of gastric juice peaked at 2 hr after stress and the ulcer index peaked at 4 hr after stress. But the local contents of CGRP in rats' pylorus decreased to the minimum at 4 hr after stress. The bile acid and ulcer index in the L-NAME group were significantly lower than in the antagonist control group. However, the bile acid in the hCGRP8-37 group was less than in the antagonist control group. Compared with hCGRP8-37 group, there was a significant reduction in bile acid in the L-NAME group. There was a significant reduction in the ulcer index of the hCGRP8-37 group compared with the L-NAME group and the antagonist control group. There was a certain kind of positive correlation between nitric oxide in rats' pylorus and bile acid to the stomach, for nitric oxide could loosen the pyloric sphincter and increase the bile acid to the stomach. L-NAME might reduce the local nitric oxide contents in rats' pylorus so that bile acid to the stomach might be decreased, obviously with a looser tight pyloric sphincter. Meanwhile, the CGRP in rats' pylorus was negatively associated with the ulcer index, hence CGRP might protect gastric mucosa under stress conditions.

Animals↗
PubMed2001

Clinical characteristics of double pylorus.

BACKGROUND: Double pylorus can occur as either a congenital abnormality or an acquired complication of peptic ulcer disease. There has been no report of long-term follow-up of a large series of patients treated for double pylorus. The objective of this study was to determine the course of double pylorus in 20 patients by serial endoscopic examination. METHODS: Among 102,958 endoscopic examinations conducted from 1987 to 1999, a diagnosis of double pylorus was made in 20 patients, 18 of whom were followed from 2 months to 10 years. The demographics, clinical presentations, and outcome, as well as endoscopic patterns of double pylorus, were retrospectively reviewed. The rates of ulcer recurrence and symptoms were estimated and compared. RESULTS: Most fistulous rings were located on the lesser curve of the gastric antrum (75%). Evolution from an original ulcer to fistula was observed in 9 patients. The fistula disappeared in 1 patient, remained open in 12, and converged with the normal pyloric ring in 5 patients. One or more associated systemic diseases and extensive treatment with various drugs were noted in 12 patients. Eradication of Helicobacter pylori in infected patients resulted in a lower percentage of patients with symptoms (36% vs. 100%) and ulcer recurrence (55% vs. 100%) compared with uninfected patients, but the differences were not statistically significant. CONCLUSION: In this study, fistula closure did not occur in the majority of patients. Associated systemic diseases and extensive use of medications might be important factors in persistence of double pylorus. Eradication of Helicobacter pylori was not beneficial in terms of relief of symptoms, prevention of ulcer recurrence, and fistula closure. Surgical intervention should be considered for patients with refractory symptoms, recurrent ulcers, and other complications.

Duodenal Diseases↗
PubMed1992

Duodenal reflux through the pylorus induces gastric adenocarcinoma in the rat.

We investigated whether duodenal reflux through the pylorus is involved in the development of gastric cancer. Male Wistar rats weighing 230-250 g were subjected to three types of operative procedures: (i) allowing reflux through the pylorus; (ii) allowing reflux through a gastrojejunal stoma; and (iii) gastrotomy. No carcinogens were given, and the animals were killed 50 weeks after surgery. No cancers were detected in any of the 18 animals with gastrotomy. In contrast, seven (41%) of 17 animals with reflux through the pylorus and four (31%) of 13 animals with reflux through the stoma had adenocarcinoma. Differences in the incidence between both reflux groups and the gastrotomy group were significant (P < 0.01 and P < 0.05 respectively). All of the adenocarcinomas developed in the pyloric mucosa near the pylorus in the animals with reflux through the pylorus, and in the oxyntic mucosa near the stoma in those with reflux through the stoma. Adenocarcinomas appeared as a polyploid mass with or without slight central erosion. Most of the adenocarcinomas were of the well-differentiated tubular type, and the others were of the mucinous type. No differences in either the histologic type or depth of invasion of the adenocarcinoma were recognized between the two duodenogastric reflux groups. Precancerous or paracancerous lesions, such as adenoma, adenocystic proliferation, and stomal pseudopyloric metaplasia, were more frequently found in the same region as the adenocarcinomas. These findings suggest that duodenogastric reflux in the rat has potent carcinogenic activities not only in the oxyntic mucosa through the stoma, but also in the pyloric mucosa through the pylorus.

Adenocarcinoma↗
PubMed1983

Mechanism of gastric acid response to pylorus ligation: effects of nephrectomy.

In the rat nephrectomy raises the serum gastrin concentration but makes the parietal cells refractory to gastrin. Pylorus ligation stimulates the gastric acid output by a long vago-vagal reflex in innervated animals and by an intramural reflex in chronically vagotomized animals. Nephrectomy reduced the acid response to pylorus ligation in vagally intact rats but enhanced it in vagotomized rats. The acid response to pylorus ligation in all the experimental groups was inhibited by a muscarinic blocker, atropine, and by an H2-antagonist, metiamide. The serum gastrin concentration was raised by nephrectomy and by vagal denervation. Histamine mobilization from gastric endocrine cells is reflected in the activity of gastric histidine decarboxylase. The enzyme activity in pylorus-ligated innervated rats was raised by pentagastrin, atropine, and metiamide. In nephrectomized rats the basal enzyme activity was high, and it was raised further, slightly but significantly, by pentagastrin. The basal enzyme activity in pylorus-ligated rats was also quite high after vagotomy, and it was raised further by pentagastrin. After vagotomy + nephrectomy the basal enzyme activity was very high; it was not raised further by pentagastrin. It appears that both vago-vagal and intramural reflexes involve a cholinergic and a histaminergic pathway, that gastrin is not important for the neurally mediated acid response elicited by pylorus ligation, and that the postulated histaminergic pathway does not involve histamine derived from the gastric endocrine-like cells.

Animals↗
PubMedDate not supplied

Postoperative evaluation of pylorus-preserving gastrectomy for early gastric cancer.

BACKGROUND/AIMS: There have been many reports proposing some advantages of pylorus-preserving gastrectomy for gastric ulcer compared to the conventional distal gastrectomy. However, it is not clear whether similar results will be obtained from the patients with early gastric cancer. METHODOLOGY: Of 50 patients with early gastric cancer, 25 underwent pylorus-preserving gastrectomy under strict criteria and the other 25 underwent distal gastrectomy with Billroth I anastomosis by the same surgeon. The subjects were then interviewed and examined periodically to assess symptoms, food intake, body weight and serum nutritional parameters. Endoscopy and a radioisotope gastric emptying test was performed 1 year after the operation. RESULTS: Many of the patients with pylorus-preserving gastrectomy complained of gastric fullness after meals, resulting in poor food intake; a significant between-group difference was found up to 1 year after the operation. A low incidence of reflux gastritis and slow gastric emptying were confirmed in the patients after pylorus-preserving gastrectomy. CONCLUSIONS: Pylorus-preserving gastrectomy has advantages over distal gastrectomy in terms of the avoidance of dumping syndrome and protection against duodeno-gastric reflux. However, more time was necessary for improved gastric fullness or food intake. Pylorus-preserving gastrectomy should be applied in younger patients with early gastric cancer expecting long survival.

Adult↗
PubMed2000

Pylorus preservation after complete gastrectomy and jejunal interposition: experimental study investigating motility and alkaline reflux.

BACKGROUND: Pylorus preservation has been proposed to reduce the disturbance in gastric emptying following gastrectomy but little is known about the role of the pylorus regarding motility patterns and alkaline reflux. AIMS: To assess the motility patterns and alkaline reflux following pylorus preservation after complete gastrectomy and jejunal interposition in the pig. METHODS: Motility patterns and alkaline reflux were studied in 12 conscious pigs before and after gastrectomy and jejunal interposition with preservation of the pylorus and a 1 cm antral ring (PYL+) or excised pylorus (PYL-) 6 and 14 weeks postoperatively. Gastroduodenal motility was investigated by manometry after fasting and fed, respectively and alkaline reflux by a fiberoptic system for detecting bilirubin. RESULTS: The number of propagated phase-III activities of the jejunal interponat to the duodenum and propagating velocity were lower in the PYL+ group after 6 weeks (p < 0.05) but higher after 14 weeks (p < 0.05) compared to the PYL- group. In the PYL+ the number of intrapyloric pressure waves (IPPWs) was lower after 6 weeks (p < 0.05) but higher after 14 weeks (p < 0.05) in comparison to preoperative controls. Alkaline reflux was significantly higher in the PYL- group than in the PYL+ group throughout the time observed. CONCLUSIONS: Pyloric function shows a delay after 6 weeks but restores within 14 weeks postoperatively. Pylorus preservation was associated with a significant decrease of alkaline reflux compared to PYL- in this setting.

Animals↗
PubMed1981

The influence of an intact pylorus on postprandial enteroglucagon and neurotensin release after upper gastric surgery.

Upper partial gastrectomy for carcinoma of the gastric cardia or fundus is unavoidably accompanied by truncal vagotomy, so it is orthodox practice to carry out pyloroplasty with this procedure. In order to assess the effect of leaving an intact pylorus in this operation, 21 patients were investigated with an oral hypertonic load (200 ml 50 per cent glucose solution), and blood was taken at intervals during the test, for the ileal gut hormones, enteroglucagon and neurotensin, as well as for measurements of haematocrit and blood glucose. Clinical features of dumping during the test were sought. There were 7 patients with upper partial gastrectomy, truncal vagotomy and an intact pylorus, 7 patients without a pylorus (total or near total gastrectomy) and 7 patients not subjected to gastric surgery. No significant difference was found in any of the measurements between gastrectomy patients with an intact pylorus and those draining through an enterostomy. However, both these groups differed significantly from normal controls in having greater rates of rise and higher peak values of enteroglucagon, neurotensin, haematocrit and blood glucose, together with a more frequent occurrence of dumping symptoms during the test. As the above measurements probably reflect transit of glucose into the small intestine, the findings in this study suggest that leaving an intact unstenosed pylorus is unlikely to lead to gastric stasis following upper partial gastrectomy.

Aged↗
PubMed1996

Cyclic motor activity of the gallbladder maintained in a pylorus-preserving gastrectomy in dogs.

The gallbladder has cyclic motor activity (CMA), which is impaired after a conventional gastrectomy. We conducted experiments to determine whether or not a pylorus-preserving gastrectomy (PPG) could maintain gallbladder CMA. Six strain gauge force transducers were implanted into the gastrointestinal tract and gallbladder of six dogs, respectively. The motor activity of the gastrointestinal tract and gallbladder was recorded as a control. PPG was then carried out. The phasic contractions of the gallbladder, which were correlated with the antral contractions in the control state, were synchronized with contractions of the pylorus after PPG. Intravenous administration of CCK-OP (40 ng/kg) induced phasic contractions of the gallbladder at 4.6 +/- 0.2 c/min in 3 of the 6 days with gastric contractions. After PPG, the gallbladder had phasic contractions (4.5 +/- 0.2 c/m), which were synchronized with the contractions of the pylorus in all dogs regardless of the contractions in the remnant stomach. These findings suggest that gallbladder CMa has a closer relationship with the CMA of the pylorus than with the remnant stomach after PPG. Thus, a preservation of the pylorus at the time of gastric surgery will help in maintaining gallbladder function and coordination with the remnant stomach.

Animals↗
PubMed1988

Importance of pepsin and stomach distension in morphological alterations of stress-induced gastric lesions in pylorus-ligated rats.

Pylorus ligation changed the morphology and location of gastric lesions induced by water-immersion stress (WI stress) in rats; linear lesions in the corpus mucosa disappeared, and punctate lesions appeared in both the corpus and antrum, in association with the loss of H+ and the gain of Na+ in the gastric contents. Oral administration of antipeptic drugs such as amylopectin sulfate and sulfated glyptide or porcine pepsin significantly prevented or aggravated the lesions, respectively, although another type of elongated lesion appeared in response to high doses of antipeptic drugs. These antipeptic drugs or exogenous pepsin significantly reduced or increased pepsin activity, respectively, without effect on the acid output. Similar punctate lesions were produced in the atropinized rats (10 mg/kg) by instillation of acid solution (100 mM HCl plus 54 mM NaCl) with pepsin into the pylorus-ligated stomach and subjecting to WI stress. On the other hand, when the gastric contents were drained through a fistula to prevent accumulation of gastric juice in the pylorus-ligated stomach, WI stress again induced linear lesions only in the corpus mucosa. Acid hypersecretion in these rats induced by intravenous infusion of histamine, tetragastrin, or carbachol significantly aggravated the severity of lesions but did not change their morphology. These results suggest that pepsin in the presence of acid is prerequisite for development of gastric lesions in pylorus-ligated rats induced by WI stress. The morphological alterations may be accounted for by the distensions of the stomach due to accumulation of gastric juice in the lumen caused by pylorus ligation, but not due to acid hypersecretion.

Animals↗
PubMed1995

Effect of occluding the pylorus on intraoral intake: a test of the gastric hypothesis of meal termination.

Meal size does not change in response to food being restricted to the stomach by occlusion of the pylorus. This result has been used as evidence for a gastric model of meal termination where feedback arising solely from the stomach is taken to underlie satiation. Such data provide support for the gastric model, however, only if the rate of gastric emptying during ingestion in the unoccluded condition is slow, such that comparable amounts of food would be found in the stomach at the end of the meal in both the pylorus-occluded and unoccluded conditions. To evaluate this tissue directly, rats were implanted with pyloric cuffs and gastric cannulas and given an intraoral intake test of a 10.5% glucose solution with either the pylorus occluded or unoccluded. At the end of each intraoral intake test, the content of the stomach was removed via the gastric cannula and it's volume and concentration measured. Occlusion of the pylorus did not change meal size, but both the volume and grams of glucose solute found in the stomach were substantially greater in the pylorus-occluded condition. These results are not consistent with the hypothesis that the stomach is the sole source of inhibitory signals that terminate a meal. Cumulative intake would appear to be accurately tracked regardless of its distribution within the digestive tract.

Animals↗
PubMed1982

[Movements of the pylorus and its neighboring segments].

An attempt has been made, by using a combined radiological-manometric technique, to study the co-ordination of the movements of the pylorus and its neighbouring segments in man. Radiological examination was carried out by fluoroscopy with video tape recording and pressure measurements by three point manometry. From these combined techniques the following results were obtained: the pylorus is not a digestive sphincter; isolated contractions of the pylorus without previous contraction of the neighbouring segments do not occur; two types of contractions occur in the prepyloric segment, leading to different behaviour of the pylorus; in the duodenal bulb there are contractions independent from antral movements also leading to a variable behaviour of the pylorus; following pentagastrin injection, the regular contractions of the pyloric canal become more rhythmical.

Adolescent↗