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Proximal Duodenum (proximal + duodenum)
Selected AbstractsMelatonin in the duodenal lumen is a potent stimulant of mucosal bicarbonate secretionJOURNAL OF PINEAL RESEARCH, Issue 4 2003Markus Sjöblom Abstract: Melatonin, originating from intestinal enterochromaffin cells, mediates vagal and sympathetic neural stimulation of the HCO secretion by the duodenal mucosa. This alkaline secretion is considered the first line of mucosal defense against hydrochloric acid discharged from the stomach. We have studied whether luminally applied melatonin stimulates the protective secretion and whether a melatonin pathway is involved in acid-induced stimulation of the secretion. Rats were anaesthetized (Inactin®) and a 12-mm segment of proximal duodenum with an intact blood supply was cannulated in situ. Mucosal HCO secretion (pH-stat) and the mean arterial blood pressure were continuously recorded. Luminal melatonin at a concentration of 1.0 ,m increased (P < 0.05) the secretion from 7.20 ± 1.35 to 13.20 ± 1.51 ,Eq/cm/hr. The MT2 selective antagonist luzindole (600 nmol/kg, i.v.) had no effect on basal HCO secretion, but inhibited (P < 0.05) secretion stimulated by luminal melatonin. Hexamethonium (10 mg/kg i.v. followed by continuous i.v. infusion at a rate of 10 mg/kg/hr), abolishes neurally mediated rises in secretion and also inhibited (P < 0.05) the stimulation by luminal melatonin. Exposure of the lumen to acid containing perfusate (pH 2.0) for 5 min increased (P < 0.05) the HCO secretion from 5.85 ± 0.82 to 12.35 ± 1.51 ,Eq/cm/hr, and luzindole significantly inhibited (P < 0.05) this rise in secretion. The study thus demonstrates that luminal melatonin is a potent stimulant of duodenal HCO secretion and, furthermore, strongly suggests melatonin as an important mediator of acid-induced secretion. [source] Effects of midazolam on small bowel motility in humansALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2000Castedal Background: Benzodiazepines are used as sedatives for some intestinal procedures and as hypnotics, and this is the reason for studying their effects on duodenojejunal motility. Methods: Antroduodenojejunal manometry was performed in 13 healthy volunteers on two different occasions, when placebo or midazolam were given intravenously (randomized, double-blind). A bolus dose of midazolam 0.03 mg/kg was followed by 0.015 mg/kg after 1.5, 3 and 4.5 h. After 5 h observation of interdigestive motility, the volunteers were given a test meal and recording continued for another hour. Twenty-eight motility variables were compared. Results: With midazolam the median motility index of phase III in the proximal duodenum was increased by 37% (P < 0.05), which was a consequence of both a longer duration (P < 0.01) and higher pressure amplitudes (P < 0.05), compared with placebo. A longer duration (9%) of phase III was also seen in the distal duodenum (P < 0.05). With midazolam the duration of the migrating motor complex was shortened by 27% (P < 0.05). No statistically significant difference was found for the number of episodes of phase III registered (P=0.09), or for the other 22 motility variables compared including the duodenal retroperistalsis in late phase III. Conclusion: Midazolam does affect some aspects of duodenal motility, especially in the proximal part, but phase III-related retroperistalsis is not affected. [source] 46 The feasibility of duodenum electrical stimulation to produce gastrointestinal symptoms in a clinical trialNEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006KA STECCO Introduction:, Proximal duodenal electrical stimulation with various energy parameters has been investigated as a possible treatment for various gastrointestinal (GI) myoelectrical diseases. Wide pulse width (millisecond) stimulation in the proximal duodenum can disrupt or entrain the normal myoelectrical rhythm and provide a potential feedback pathway to alter normal gastric function such as emptying, fundus tone, and intra-gastric pressure and subsequently produce specific symptoms that could affect eating behaviors. A specific level of electrical stimulation is necessary to elicit symptoms and serve as an indicator that energy parameters are adequate. However, there has been no published data correlating electrical threshold stimulation with symptom characterization. The goal of this study was to determine the average minimum pulse width necessary to elicit GI symptoms. Methods:, Eight patients underwent endoscopic placement of intraluminal electrodes in the proximal duodenum. Each patient received electrical stimulation in the millisecond (ms) range starting with a pulse width of 100 ms that was increased by intervals of 100 ms up to a maximum pulse width of 500 ms. The pulse repetition frequency was fixed at 12 CPM and each regimen was repeated for amplitudes ranging from 2 milliamps (mA) to 10 mA. Gastrointestinal symptom scores consisting of nausea, vomiting, satiety, fullness, pain, bloating and other, were taken at baseline and after each regimen change. Results:, There was an average minimum threshold necessary for elicitation of symptoms (293.7 + 41.7 ms, p-value = 0.063). The three most frequently reported GI symptoms were crampy abdominal pain, fullness, and bloating. Conclusions:, Electrical stimulation of the duodenum is feasible. A certain minimum threshold of duodenal electrical stimulation is necessary to elicit GI symptoms in patients. The intensity and patient tolerability of each specific GI symptom was able to be adjusted by changing a certain energy parameter within a regimen. Further research is warranted to evaluate the ability of duodenal electrical stimulation to produce GI symptoms that may alter eating behaviors. [source] Low antroduodenal pressure gradients are responsible for gastric emptying of a low-caloric liquid meal in humansNEUROGASTROENTEROLOGY & MOTILITY, Issue 1 2002T. HAUSKEN The motor mechanisms responsible for transpyloric flow of gastric contents are still poorly understood. The aim of our study was to investigate the relationship between luminal pressures and gastric wall motion and between gastroduodenal pressure gradients and pressure waves, and ante- and retro-grade transpyloric flow. In eight healthy volunteers, intraluminal pressures were recorded from the antrum and proximal duodenum. Transpyloric flow was monitored simultaneously using duplex ultrasonography, before, during and after ingestion of 300 mL meat soup. Transpyloric emptying occurred as sequences of alternating periods of emptying,reflux,emptying. Approximately one-third of the sequences were not associated with peristalsis. The antroduodenal pressure gradients were significantly lower during nonperistaltic-related emptying than during peristaltic-related emptying (0.15 (0,0.3) kPa, and 1.7 (0.2,2.0) kPa, respectively [mean ± (range)], P < 0.005). The duration of emptying episodes not associated with peristalsis were significantly longer than those associated with peristalsis at (6.5 (3,8.7) s and 4.4 (2,6) s, respectively, P=0.059). Manometry detected only 56% of the antral contractions seen on ultrasound. We concluded that gastric emptying of a low-calorie liquid meal occurs both during peristaltic and nonperistaltic antral activity. In spite of lower antroduodenal pressure gradients, the emptying episodes were longer for nonperistaltic emptying, which is likely to be caused by low pyloric resistance. Considerable flow seems to occur without peristalsis during gastric emptying of a low-calorie, liquid meal in humans. [source] Oesophageal and gastric bile exposure after gastroduodenal surgery with Henley's interposition or a Roux-en-Y loopBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2004J.-Y. Mabrut Background: The degree which the various reconstruction techniques prevent bile reflux after gastroduodenal surgery has been poorly studied. Methods: Bile exposure in the intestinal tract just proximal to the jejunal loop was measured with the Bilitec 2000® device for 24 h after gastroduodenal surgery in three groups of patients. Group 1 comprised 24 patients with a 60-cm Henley's loop after total gastrectomy. Group 2 included 31 patients with a 60-cm Roux-en- loop after total (22 patients) or subtotal (nine) gastrectomy. Group 3 contained 21 patients with a 60-cm Roux-en- loop anastomosed to the proximal duodenum as part of a duodenal switch operation for pathological transpyloric duodenogastric reflux. Bile exposure, measured as the percentage time with bile absorbance greater than 0·25, was classified as nil, within the range of a control population of healthy subjects, or pathological (above the 95th percentile for the control population). Reflux symptoms were scored and all patients had upper gastrointestinal endoscopy. Results: Bile was detected in the intestine proximal to the loop in none of 24 patients in group 1, eight of 31 in group 2 and 12 of 21 in group 3 (P < 0·001). The mean reflux symptom score increased with the degree of bile exposure, and the proportion of patients with oesophagitis or gastritis correlated well with the extent of bile exposure (P < 0·001). Conclusion: A long Henley's loop was more effective in preventing bile reflux than a long Roux-en- loop. Bilitec® data correlated well with the severity of reflux symptoms and the presence of mucosal lesions. Copyright © 2004 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. 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