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PubMed1990

Different effects of cytoprotective drugs on ethanol- and aspirin-induced gastric mucosal injury in pylorus-ligated rats.

In anesthetized rats oral administration (2 ml) of both ethanol (50% in 150 mM HCl) and aspirin (80 mM in 150 mM HCl) produced bandlike lesions in the stomach, while more generalized lesions occurred in the pylorus-ligated stomach when the irritant was given intragastrically through the fistula prepared in the rumen and the mucosal folds were removed by stomach distension. The bandlike lesions induced in the intact stomach by both irritants were significantly and dose-dependently prevented by 16,16-dimethyl PGE2 (dmPGE2: 3 and 10 micrograms/kg, subcutaneously), cysteamine (30 and 100 mg/kg, subcutaneously) or timoprazole (10 and 30 mg/kg, per os) at the doses which significantly inhibited gastric motility. In the pylorus-ligated stomach, however, neither of these agents showed any protection against the generalized lesions induced by ethanol, but such lesions caused by aspirin were significantly prevented only by dmPGE2. These agents also showed similar effects against the reduction of transmucosal PD in the pylorus-ligated stomach exposed to ethanol and aspirin. These results suggest that (1) the formation of bandlike lesions caused by ethanol and aspirin depends on the presence of mucosal folds and may be prevented by the agents that inhibit gastric motility, (2) the pathogenesis of the lesions induced by aspirin and ethanol may be different in the pylorus-ligated stomach, and (3) dmPGE2 has a unique protective ability that is not shared by usual cytoprotective agents.

16,16-Dimethylprostaglandin E2↗
PubMed2005

Elevated cyclooxygenase-2 expression in patients with early gastric cancer in the gastric pylorus.

BACKGROUND: Duodenogastric reflux after surgery increases the risk of gastric carcinoma. To determine whether bile reflux influences the development of gastric cancer in patients who have not had surgery, we compared cyclooxygenase-2 (COX-2) immunoreactivity in early gastric cancer originating from the gastric pylorus and that originating from other locations. We also examined the effects of bile acids on the expression and activity of COX-2 in gastric cells in vitro. METHODS: Tumor sections from 79 patients who underwent endoscopic mucosal resection for early intestinal-type gastric carcinoma were stained using a COX-2-specific monoclonal antibody. Immunoblotting of COX-2 was used to assess the effects of bile acids on COX-2 expression and activity in human gastric cell lines. RESULTS: Among the 79 early gastric cancer lesions studied, 13 (16%) arose in the gastric pylorus. In this group, COX-2 immunoreactivity was negative to weak in 38% (5 of 13 lesions) and moderate to strong in 62% (8 of 13 lesions). In the control group, COX-2 immunoreactivity was negative to weak in 70% (46 of 66 lesions) and moderate to strong in 30% (20 of 66 lesions). COX-2 expression was significantly elevated in early gastric cancer located in the gastric pylorus, compared with that in the other locations. In human gastric cell lines, bile acids induced COX-2 expression, mediated by the ERK 1/2 mitogen-activated protein kinase pathway. CONCLUSIONS: COX-2 expression is elevated in early gastric cancer of the gastric pylorus, a common site of gastric cancer. Bile acids induced COX-2 expression in human gastric cell lines, suggesting a role of bile reflux in gastric carcinogenesis.

Adenocarcinoma↗
PubMed1988

Motor activity of the gastric antrum, pylorus, and duodenum under fasted conditions and after a liquid meal.

Because the mechanisms that control the movement of food and digestive juices across the human pylorus are not completely understood, the aim of this study was to document the normal patterns of pressure activity in the antrum, pylorus, and duodenum and the associated pH changes in 9 healthy volunteers. Studies were carried out under fasting conditions and after ingestion of 300 ml of chocolate milk, using a unique 11-channel intraluminal probe that incorporated a sleeve sensor positioned across the pylorus and pH electrodes situated in the terminal antrum and proximal duodenum. The most common motor pattern recorded under fasting conditions consisted of regular coordinated contractions, most of which (a) involved the antrum and duodenum, (b) showed evidence of propagation through two or more adjacent channels, and (c) were associated with transient reductions in duodenal pH and transient elevations in antral pH. Ingestion of milk changed the motor pattern to one that was composed of pressure waves, which were confined to the pylorus with few or no pressure waves in the terminal antrum or proximal duodenum. Isolated pyloric pressure waves were gradually replaced by propagated antroduodenal contractions, which eventually occurred at a regular frequency that was higher than that observed under fasting conditions. After ingestion of milk, only the coordinated contractions were associated with transient reductions in duodenal pH. Isolated pyloric pressure waves were also observed under fasting conditions just before or just after phase III of the migrating motor complex, and 17% of these were accompanied by episodes of duodenal acidification.

Adult↗
PubMed2006

Method of pyloric reconstruction and impact upon delayed gastric emptying and hospital stay after pylorus-preserving pancreaticoduodenectomy.

Preservation of the pylorus at the time of pancreaticoduodenectomy has been associated with equal oncological outcomes when compared to the classical Whipple operation. Multiple studies have demonstrated that pylorus-preserving pancreaticoduodenectomy (PPPD) has equal or superior outcomes regarding quality of life when compared with the traditional Whipple operation, but many studies have suggested a higher incidence of delayed gastric emptying (DGE). DGE prolongs hospital stay, and its association with PPPD has hampered its adoption by many pancreatic surgery centers. We describe a novel surgical technique for the prevention of delayed gastric emptying following pylorus-preserving pancreaticoduodenectomy. The technique of pyloric dilatation appears to decrease the incidence of delayed gastric emptying and facilitates earlier hospital discharge, when compared with standard pylorus preserving pancreaticoduodenectomy.

Abdominal Abscess↗
PubMed1983

Double pylorus--in evolution.

Double pylorus is a rare abnormality. Over a 4-year period, we have found two cases of double pylorus in 2,500 endoscopic examinations, an incidence of 0.08%. In one patient, the development of double pylorus from a prepyloric ulcer was followed by serial endoscopies. Most cases of double pylorus are acquired from peptic ulcer disease.

Duodenal Diseases↗
PubMed1985

Specific effects of thoracic vagotomy on the electrical activity of the gastric antrum and pylorus in rabbits.

The electrical activity of the antrum and the pylorus was recorded in rabbits, with chronically implanted electrodes. Effects of food intake were studied before and after bilateral vagotomy (b.v.), ventral vagotomy (v.v.) or dorsal vagotomy (d.v.) performed just above the diaphragm. In fasted animals, the electrical activity was characterized by bursts of potentials at a frequency of 1.93 +/- 0.09/min, initiated 45 mm or 20 mm from the pylorus in the greater and the lesser curvature respectively. The velocity of propagation of the bursts increased from 5-6 mm/s in the proximal antrum to 12-25 mm/s in the last 10 mm of the antrum along the greater curvature and from 2-4 mm/s to 5-15 mm/s along the lesser curvature. Feeding led to a rapid increase in the frequency of both antral and pyloric bursts up to 4.01 +/- 0.10/min, lasting 30-60 min after a large meal but only 15 min when the amount of food was restricted. The behaviour of the rabbits was not significantly affected by bilateral or ventral vagotomy. In contrast, dorsal vagotomy resulted in a drastic decrease of food intake. The mean frequency (fo) of bursts before meals was significantly reduced after vagotomy in v.v. animals (1.49 +/- 0.11/min, P less than 0.02) and in d.v. animals (1.34 +/- 0.08/min, P less than 0.001) but not in b.v. or sham-operated rabbits. For the first 3 d after surgery, the frequency (f) of bursts during the 30 min after the beginning of meals was significantly different from fo and reduced relative to f before nerve sections (1.9 +/- 0.11/min and 2.32 +/- 0.20/min respectively in b.v. and v.v. animals). In sham-operated animals, the value of f was closely similar to f before surgery. The effects of meals on the frequency of bursts were again similar to the effects in intact animals within 4-6 d for v.v. animals and 6-9 d for b.v. animals. In the pylorus, a different pattern for electrical activity, which consisted of trains of spikes at a frequency of 0.3/s, was superimposed on the bursts and was most marked in d.v. animals. The spiking activity was not affected by atropine, phentolamine or propranolol. The role of the vagus nerve in the motile responses of the antrum to food intake is discussed. These results indicate the existence of a non-cholinergic, non-adrenergic innervation of the pylorus which is involved in the opening of the sphincter and appears to be mediated by the dorsal vagal trunk.

Animals↗
PubMed1989

Inhibitory function of VIP-PHI and galanin in canine pylorus.

Contractions of canine pylorus and adjacent muscles were recorded with antral and duodenal strain gauges and a Dent sleeve manometric assembly with additional side holes in the pylorus. In vivo, vasoactive intestinal polypeptide (VIP) and peptide histamine isoleucine (PHI) given through the gastroepiploic artery inhibited both spontaneous and acetylcholine-induced pyloric contractions, before and after neural blockade with tetrodotoxin. Galanin inhibited only nerve-stimulated contractions. VIP greater than PHI much greater than galanin inhibited pyloric motor activity initiated by field stimulation of duodenal intramural nerves or intraduodenal infusion of 0.1 N HCl. In vitro, forskolin or field stimulation of nerves inhibited contractions of the pyloric muscle induced by various agonists but VIP-PHI failed to inhibit these contractions on two-thirds of the strips. The in vivo results suggest that VIP (or PHI) may be an inhibitory mediator in the pylorus acting directly on smooth muscle. Galanin may inhibit neural excitatory pathways in the pylorus. However, the structures on which VIP and PHI act in vivo may have become nonfunctional in vitro and other mediators account for the neural inhibition observed in isolated strips.

Acetylcholine↗
PubMed1989

Mechanics and neuropeptide responses of feline pylorus and gastric muscle in vitro.

Mechanical properties and neuropeptide responses were compared for feline pyloric and gastric muscle under isometric conditions in vitro. Total tension in antral circular muscle (0.699 +/- 0.003 kg/cm2) was less than in corpus circular (1.597 +/- 0.007 kg/cm2) or longitudinal muscle from the lesser and greater curvatures (1.256 +/- 0.009 and 1.253 +/- 0.007 kg/cm2, n greater than or equal to 55, P less than 0.05). The components of tension at optimal length were similar for all gastric muscles (P greater than 0.1). The pylorus maintained less total tension (0.335 +/- 0.003 kg/cm2) and a greater component of resting tension (75.6%) than gastric muscle (P less than 0.01). Substance P, cholecystokinin-8 (CCK-8), and neurotensin varied in potency and efficacy in circular muscle of the antrum, corpus, and inferior portion of the pyloric ring. Longitudinal muscle and the superior portion of pylorus responded poorly if at all to neuropeptides. Substance P- but not CCK-8- or neurotensin-induced contractions of gastric muscle were reduced by tetrodotoxin (TTX) and atropine (P less than 0.05). Substance P-induced pyloric contractions were TTX sensitive (P less than 0.05) but were unaffected by atropine. We concluded that 1) length-tension properties of gastric muscle are similar and distinct from the pylorus and that 2) neuropeptide efficacy varies regionally within the feline stomach and within the pylorus.

Acetylcholine↗
PubMed1994

Serotonin contracts the isolated rat pylorus via a 5-HT2-like receptor.

Serotonin (5-HT) produced concentration-dependent contractions of the isolated rat pylorus in vitro. Serotonergic contractions were antagonized by the calcium L-channel blocker, diltiazem, but not by tetrodotoxin or atropine. Three drugs that block 5-HT2 receptors, ketanserin, xylamidine, and methysergide, unsurmountably inhibited contractions to 5-HT. In contrast, antagonists of 5-HT3, 5-HT1A/1B, beta-adrenergic, or alpha 1-adrenergic receptors did not alter the response to 5-HT. Devazepide, an antagonist of cholecystokinin (CCK) type-A receptors, blocked contraction produced by CCK-8 but not by 5-HT. Conversely, the 5-HT2 antagonists did not affect CCK-stimulated contraction. These results suggest that 5-HT contracts the pylorus by a 5-HT2-like receptor on muscle and that this response occurs independently of CCKergic receptor mechanisms. Furthermore, the parallel between the overall pharmacological profile for serotonergic contraction of the pylorus and that observed previously for the anorectic action of peripheral 5-HT makes the pylorus a logical candidate for peripheral serotonergic control of feeding.

Animals↗
PubMed1989

Pylorus preserving pancreatoduodenectomy versus Whipple procedure for adenocarcinoma of the head of the pancreas.

Thirty eight patients underwent pancreatoduodenectomy for histologically confirmed adenocarcinoma of the head of the pancreas. Twenty one underwent a pylorus preserving pancreatoduodenectomy and seventeen the classical Whipple procedure. We undertook this retrospective analysis to compare longterm survival following the two different surgical procedures. Patients in the two groups were comparable for preoperative laboratory data, age and pathological staging. Minor and major morbidity was not different between the two group (33.3% and 35.2% respectively). In the pylorus preservation group a delayed resumption of full oral diet and a consequent prolonged hospital stay has been noted (21.3 days vs 15.4 days, p less than 0.05). Mean survival was 21 months in the pylorus preservation group and 17 in the Whipple group. No statistical difference was observed between the two survival curves. According to these data the pylorus preserving pancreatoduodenectomy represents a reasonable option for adenocarcinoma of the head of the pancreas.

Adenocarcinoma↗
PubMed2002

[Treatment of complications of pylorus preserving stomach resection].

Causes of unsatisfactory outcomes of pylorus preserving stomach resection are analyzed, method of prophylaxis and surgical correction is proposed. Pylorus preserving stomach resection was performed in 207 patients with chronic gastric ulcer. 2 groups of patients were compared: 166 patients who have undergone pylorus preserving stomach resection by Maky--Gorobashko (group 1); 41 patients operated according to an original method of suprapyloric stomach resection with preserving of distal Latarget nerves on serous-muscular flap formed from lesser curvature of the stomach (group 2). Of 122 examined patients of group 1 excellent and good long-term results according to Visick's criteria were achieved in 101 (82.79%), satisfactory--in 12 (9.84%), unsatisfactory--in 9 (7.37%). Bad stump evacuation due to a stable spasm of the denervated pylorus and hypokinesia of the stump were the main causes of unsatisfactory results. In group 2-39 of 41 patients were examined in long-term period. Excellent and good results were achieved in 38 patients, satisfactory--in 1. There were no unsatisfactory results.

Chronic Disease↗
PubMed2003

Double pylorus.

Double pylorus (DP) or duplication of the pylorus is an uncommon condition that is either congenital or acquired. Acquired double pylorus (DP) results from a peptic ulcer eroding through and creating a fistula between the duodenal bulb and the distal stomach. We report a case of an acquired double pylorus in an adult gentleman that resulted from the erosion of a duodenal and prepyloric ulcer.

Duodenal Ulcer↗
PubMed2004

Multivariate analysis of technical variables in pancreaticoduodenectomy: the effect of pylorus preservation and retromesenteric jejunal position on early outcome.

BACKGROUND: To evaluate the effect of technical modifications to pancreaticoduodenectomy (PD) on postoperative outcome, we established a register of all patients undergoing PD at Victoria General Hospital (Queen Elizabeth II Health Sciences Centre), a tertiary care, university-affiliated hospital. PATIENTS AND METHOD: Data from 78 consecutive patients who underwent PD from January 1998 through November 2000 were collected for univariate and multivariate analyses of clinical and technical factors on early outcome after PD, including duration of gastric stasis, development of complications and length of hospital stay. RESULTS: Two patients (2.6%) died; complications were recorded in 43 (55%). Upon univariate analysis, 3 factors (a diagnosis of chronic pancreatitis, pylorus preservation, and route of the jejunal limb) significantly affected duration of gastric stasis; but on multivariate analysis, only pylorus preservation and jejunal-limb route remained significant. Retromesenteric jejunal-limb placement was associated with longer periods of gastric stasis (mean 11.9 d, standard deviation [SD] 8.1 d) than the antemesenteric (retrocolic) route (mean 7.2, SD 3.6 d; p < 0.05); likewise pyloric preservation (mean gastric stasis 10.4 d, SD 5.9 d) compared with resection of the pylorus (mean 7.0 d, SD 3.2 d; p < 0.05). Pancreatic leaks occurred in 18% of retromesenteric and 8% of antemesenteric reconstructions (p = 0.3). Fewer patients with mucomucosal pancreaticojejunostomy suffered complications than those with invaginated anastomoses, but their hospital stays were similar in length. CONCLUSION: Route of the jejunal efferent limb and preservation of the pylorus are independent technical variables affecting early outcome after PD.

Adult↗
PubMed1991

[Motility of antrum, pylorus, and duodenal bulb: importance of radiologic series analysis in man].

The quantification of gastroduodenal motility uses invasive methods. The aim of our study was to further characterize the contractility of antrum, pylorus and duodenal bulb in two states, using a new, non invasive fluorographic method. Healthy volunteers (mean age = 28) were involved in this study under fasting conditions (n = 20) and after a meal (n = 20). In both conditions, the subjects have swallowed 250 ml of a barium sulfate solution for fluoroscopic gastrographies taken every 2 seconds, during 30 s. Spot films were analysed using a graphic table and locally developed microcomputer program to generate space-time diagrams of antral and duodenal areas and of pylorus diameters. For each subject, the antral CA, duodenal CB contractilities (maximal variation of antral, duodenal areas in p 100) and pylorus contractility CP (closure during the observation time in p 100) were calculated. CA values were high in the two situations, but did not differ (81.1 p 100 vs 82.5 p 100 post-prandial). In contrast, CP was higher under fasting (54.0 p 100) than in post-prandial (15.0 p 100; p less than .001). Two pyloric motor patterns were observed in post-prandial: A--pyloric contractions in relation with the end of antral contraction B--augmented pyloric resistances observed during the end of antral contraction and also associated with duodenal contractions. CB was low in post-prandial (27.0 p 100) compared to fasting CB (50.8 p 100; P less than .001). This method is reproducible and simple to use. It allows quantification of contractility and coordination in the antrum, pylorus and duodenal bulb. It may be useful to assess gastroduodenal motility under pathological conditions.

Adult↗
PubMed1979

Prolonged endoscopic and manometric observations of the pylorus.

Functional aspects of the antral-pyloric segment were evaluated in 30 patients without gastroduodenal disorders by means of prolonged endoscopic observations. Patients were examined in standardized conditions. Pressure measurements of the antrum, pylorus and duodenal bulb were assessed by means of water-perfused polyvinyl tubes in 7 patients of the same group a few days after the endoscopy. The pylorus appeared open in above 80% of the total endoscopic observation time. Pyloric closure was observed only for few seconds at the end of 30-40% of antral peristaltic waves. The antrum and pylorus appeared to contract in sequence. Antral peristaltic waves moved at a mean rate of 2.4 per minute and duodenal reflux was observed at a mean rate of 0.96 per minute usually in the form of bubbles. The manometric measurements by means of pull through in 7 patients and immediately after by means of prolonged registration carried out in a fixed position in 4 patients failed to show a high pressure zone in the gastroduodenal junction. In some cases it was possible to observe a peculiar phasic activity in the pyloric tract. The endoscopic and manometric observations suggest that human pylorus does not act as a true physiological sphincter. These findings confirm the functional aspects described by radiology and manometry in other studies. In this way, endoscopy appears to be a useful procedure to evaluate some functional aspect of the gastroduodenal tract.

Adult↗
PubMed1984

[Double pylorus and pyloroduodenal fistulas: two case reports and discussion].

Congenital double pylorus is extremely rare; only 2 cases have been found in the English and French literature. Acquired double pylorus occurs more often; up to 1982, 66 cases had been reported. During 6 810 consecutive barium meal examinations over a period of 2 years, we diagnosed the condition in 5 patients. Two came to operation, at which the diagnosis was confirmed. These 2 cases are described. Acquired double pylorus is in reality a short pyloroduodenal fistula situated next to the pylorus, usually on the lesser curvature side. In the majority of cases it results from a pyloric ulcer penetrating into the duodenum. In a minority of cases the primary lesion is a duodenal ulcer penetrating into the pyloric area. Cases initially present with peptic ulcer symptoms. With the formation of the fistula, symptoms may disappear. Some authorities consider this to indicate spontaneous cure of the ulcer, thus obviating the need for further medical or surgical treatment. In the present 2 cases there was no remission of symptoms. None of the cases has been associated with malignant disease. It is thought that the condition may be recognized more often in future.

Aged↗
PubMed1995

Gastrointestinal motor activity after pylorus-preserving gastrectomy with or without vagotomy in dogs.

BACKGROUND: In the present study we evaluated gastrointestinal motility after gastrectomy of a new pylorus-preserving technique that is becoming a popular operation for early stage carcinoma of the stomach. STUDY DESIGN: Using strain-gauge force transducers we studied gastrointestinal motility in control dogs, dogs after pylorus-preserving gastrectomy, and dogs after conventional distal gastrectomy with Billroth I reconstruction. Dogs with gastrectomy were reoperated upon after recording motility patterns, and the effect of vagal denervation of the gastric remnant on motility was investigated. Overall motility pattern, length of the digestive phase in the jejunum, and interval of the interdigestive phase III contractions were studied and compared among the three groups. RESULTS: In dogs after gastrectomy without vagal denervation, the regular occurrence of interdigestive phase III contractions from the gastric remnant to the jejunum was identified. In dogs after gastrectomy with vagal denervation, however, no apparent interdigestive phase III contractions were observed in the gastric remnant. The duration of the digestive phase in the jejunum, which correlates with postprandial gastric emptying, was not different between the control dogs and the dogs having pylorus-preserving gastrectomy. However, this duration was significantly shorter in dogs having conventional distal gastrectomy compared with the control dogs, not only before but after vagal denervation. CONCLUSIONS: These results indicate that the postoperative motor function after pylorus-preserving gastrectomy may be superior to that after conventional distal gastrectomy with Billroth I reconstruction.

Animals↗
PubMed1995

Double pylorus: report of a longitudinal follow-up in two refractory cases with underlying diseases.

Double pylorus is either a congenital abnormality or an acquired complication of peptic ulcer disease. We had followed two patients for 3 and 5 yr, respectively, to observe the processes of formation and the prognosis of double pylorus. Initially, duodenal ulcer was found in one patient with diabetes mellitus and chronic renal failure, and gastric ulcer was found in the other with chronic obstructive pulmonary disease. Both developed double pylorus with refractory courses. In spite of intensive medical treatment, both of them had persistent ulcers in the fistulous tract and failed to develop reepithelization. Helicobacter pylori was found in all of the specimens of gastroduodenal biopsies in both cases. Therefore, we believe that the refractory courses of double pylorus may be related to the underlying diseases and/or the presence of H. pylori. Antibacterial treatment of H. pylori or surgical intervention should be considered for patients with this condition.

Aged↗