PubMed Health⌕ Search

Biomedical subjects

J E Valenzuela

Publications and source records attributed to J E Valenzuela.

At least 55 records · Page 3Linked to original sources
PubMed1985

Abnormalities of interdigestive motility complex and increased duodenogastric reflux in gastric ulcer patients.

Just as cyclic changes in motility and secretions occur during fasting, recent evidence demonstrates that duodenogastric reflux during fasting is also cyclic and related to the motility and secretory variations. We investigated the characteristics of the migrating motility complex and duodenogastric reflux in 17 patients with gastric ulcer and compared these characteristics to those of 16 healthy subjects. We found three abnormalities of the complex in patients with gastric ulcer: (1) the antral motility was significantly decreased during the phase II of the complex (P less than 0.05) when compared to controls; (2) in about two thirds of them, the phase III of the complex was initiated at the duodenum or more distally; and (3) the mean bile salt concentration in the gastric aspirate was significantly higher (P less than 0.05) than that of the controls. We observed no relationship between the ulcer activity, the location of the crater, and the motility or reflux abnormalities.

Adolescent↗
PubMed1985

Effects of aspirin and prostaglandin E2 on interdigestive motility complex and duodenogastric reflux in man.

Both increased duodenogastric reflux and chronic aspirin ingestion are associated with the development of gastric ulcers in man. Animal studies suggest aspirin increases duodenogastric reflux. Prostaglandin E2 protects gastric mucosa from the effects of many injurious agents and inhibits gastric motility, but its effect on duodenogastric reflux is unknown. We have studied the effects of aspirin and a synthetic derivative of prostaglandin E2 on duodenogastric reflux during fasting in six normal subjects, while concomitantly monitoring gastrointestinal motility by means of a perfused catheter system. We found that duodenogastric reflux (as measured by bile salt output in gastric aspirates) increased significantly (P less than 0.05) following both the prostaglandin E2 derivative and aspirin. This increase occurred in phases II and III of the interdigestive motility complex. Both drugs were associated with a significant reduction (P less than 0.05) in frequency and amplitude of antral contraction during phase II. Both drugs also induced a significant disruption (P less than 0.01) of phase III, increasing the number of complexes without an antral and duodenal component. These effects of aspirin may be one of the factors predisposing to the gastric mucosal damage associated with aspirin. The prostaglandin E2 derivative protects gastric mucosa by mechanisms other than reducing duodenogastric reflux and ameliorating the motility disturbances caused by aspirin.

Adult↗
PubMed1985

A continuous manometric study of the human pylorus.

Previous manometric studies of the pylorus in humans have yielded conflicting data. These interstudy variations may be the result of differences in technique. It is also possible that pyloric pressure shows cyclic variations with the interdigestive motility complex. Pyloric pressure was monitored continuously for 300 min in 6 healthy men by means of a Dent sleeve. Gastroduodenal activity was measured simultaneously by using a perfused catheter system with two antral and two duodenal ports. With this method the pylorus was shown to have no elevation in basal pressure above baseline duodenal pressure during phase III. Basal pyloric pressure varied between subjects in phases I and II, being elevated in some but not in others. Subjects restudied on a separate day often showed a different pattern of activity. Pyloric pressure increased gradually in response to duodenal acidification. This response was blocked by pretreatment with naloxone. The pylorus also showed phasic activity, which was maximal in phase III. This phasic activity could not be distinguished from that of the adjacent antrum and duodenum. In conclusion, pyloric pressure patterns showed marked variation within and between subjects. These variations may explain some of the differences between previous studies.

Adult↗
PubMed1984

Comparative effect of gastrin on hydrogen ion secretion, antroduodenal motility and the interdigestive motility complex (IDMC) in man.

The physiological role of gastrin in H+ secretion is well established. We decided to study the effects of physiological doses of gastrin (as evidenced by H+ secretion and postprandial serum gastrin levels) on antroduodenal motility in order to delineate its role in antral motility regulation. Nine healthy male subjects, mean age 31 years, had two studies on different days. On day 1, gastroduodenal motility was monitored with a continuously perfused catheter system while gastric secretions were aspirated. After a basal period of 45 min, human synthetic gastrin (hG-17) was infused intravenously in consecutive doses of 6.25, 25, 100, and 400 pmol/kg/hr during 45 min each. On day 2, all subjects had a standard protein meal. Blood was withdrawn on both days for gastrin measurement by RIA. Increasing amounts of hG-17 caused a stepwise increase in serum gastrin and acid output. The D50 for H+ secretion was 25 pmol/kg/hr hG-17. The mean postprandial gastrin level was 31 +/- 5 pM, a level which was comparable to that seen during infusion of hG-17 6.25 pmol/kg/hr. At these serum gastrin levels, antral motility was either reduced or unchanged. Duodenal motility was unchanged. A reduction in the antroduodenal motility ratio was seen at these levels, but there was no interruption of the interdigestive motility complex. These results suggest that at physiological levels, gastrin by itself does not seem to have a major role in human antroduodenal motility regulation.

Adult↗
PubMed1984

Double-contrast barium meal and upper gastrointestinal endoscopy. A comparative study.

One hundred randomly selected inpatients were examined with both double-contrast barium meal and endoscopy in a blinded prospective fashion. All studies were done by staff personnel, with equal clinical information available to both the radiologist and endoscopist. The final diagnosis was made by a review committee of participating radiologists and endoscopists. Endoscopy was more sensitive (92% versus 54%, p less than 0.001) and specific (100% versus 91%, p less than 0.05) than the double-contrast barium meal. Both procedures significantly affected the clinical outcome of the patient, the effect of endoscopy being significantly greater than that of the double-contrast barium meal. Although errors with the barium study related predominantly to an inability to show subtle lesions, poor patient cooperation and perceptual and technical failures were additional significant factors. Endoscopy is recommended for certain groups of patients.

Adult↗
PubMed1984

Dopamine antagonists in the upper gastrointestinal tract.

Certain dopamine antagonists have gained increasing clinical use because of their effect on the motility of the upper gastrointestinal tract. Dopamine, while acting through specific dopaminergic receptors, inhibits lower oesophageal sphincter pressure (LOSP) and gastroduodenal motility. When given with dopamine, the specific dopamine antagonists metoclopramide and domperidone counteract these effects. When given alone, these agents elicit an increased LOSP and stimulate gastroduodenal motility and gastric emptying. They have consequently proved to be of value in certain cases of gastroparesis, and in relieving nausea and vomiting. They also appear to be useful in the management of reflux oesophagitis.

Diabetic Neuropathies↗
PubMed1984

Variations in gastric and duodenal motility during gastric emptying of liquid meals in humans.

The gastric emptying of liquids is determined by the pressure gradient between the stomach and the duodenum. This study monitored intragastric and intraduodenal pressures of 7 healthy volunteers during the gastric emptying of an acid meal (pH 2) and an oleate meal (50 mM) in comparison with the gastric emptying of a 154 mM saline meal (pH 7) in order to elucidate the mechanisms of delayed gastric emptying seen with the acid and the fatty meals. Antroduodenal motility was measured by means of a continuously perfused catheter system, and fundic pressure was monitored by means of a water-filled balloon. Gastric emptying was measured with the double sampling dye dilution technique. As expected, the gastric emptying of the pH 7 meal (t 1/2 = 2.2 +/- 0.7 min) was significantly faster than that of the acid (t 1/2 = 11 +/- 2.1 min) and the oleate (t 1/2 = 18 +/- 2 min) meals. The rapid gastric emptying of the neutral meal was consistently associated with a significant increase in tonic fundic pressure (p less than 0.05), a feature never seen with the acid and the oleate meals. There was no change in duodenal motility with the gastric emptying of the neutral meal, whereas duodenal activity did tend to increase with the acid and oleate meals. Thus the proximal stomach appears to be the main determinant of variations in the gastric emptying of liquids, whereas the duodenum appears to have a less prominent role.

Adult↗
PubMed1984

Duodenal volume and osmoreceptors in the stimulation of human pancreatic secretion.

It is generally accepted that the intestinal phase of pancreatic secretion is initiated by the stimulation of chemoreceptors sensitive to fat and protein degradation products and hydrogen ions. The effect of the volume and osmolality of food emptied by the stomach into the duodenum has received less attention. We investigated the effects of these factors on the stimulation of pancreatic secretion by studying 8 healthy male volunteers (ages 23-69 yr), in random order on 3 separate days. On day 1, an amino acid mixture (L-phenylalanine, L-tryptophan) was infused intraduodenally at increasing rates, 0.2, 0.8, and 3.2 ml X min-1. On day 2, normal saline was infused into the intestine at the same increasing rates. On day 3, mannitol solutions of increasing osmolality 370, 520, and 700 mosmol X kg-1 were infused into the duodenum at 0.2 ml X min-1. Duodenal contents were continuously aspirated via a double-lumen tube and PEG 4000 was used as a recovery marker. All studies were repeated 90 min later during i.v. infusion of atropine (20 micrograms X kg-1 X h-1). Increasing volumes of amino acids significantly increase amylase and bicarbonate output (p less than 0.05) in a stepwise fashion. Increasing volumes of saline also caused a similar stepwise increase in amylase and bicarbonate output. Furthermore, increasing osmolality caused an increase in enzyme output up to 520 mosmol X kg-1 and no increase was seen thereafter. The responses seen with volume and osmolality were approximately 40% of that obtained with the amino acids. All responses were significantly reduced (p less than 0.05) during atropine infusion. We conclude that the human duodenum contains receptors for volume and osmolality that stimulate both pancreatic enzyme and bicarbonate secretion. Both mechanisms are atropine sensitive, suggesting they are mainly neurally mediated.

Adult↗
PubMed1983

Cholinergic component in the human pancreatic secretory response to intraintestinal oleate.

To determine the role of cholinergic reflexes on pancreatic secretory response to food, we studied the effect of atropine on amylase secretion in response to the octapeptide of cholecystokinin (CCK8) and to intraintestinal oleate. Four studies were done in six healthy volunteers. The duodenal content was aspirated by a double lumen tube while synthetic secretin (41 pmol/kg/h) was infused as a background in all the studies. Graded doses of CCK8 IV or 0.42 M oleate pH 9.4 at 25 ml/h into the intestine with and without atropine 1.8 mg were given on different days. CCK-like immunoreactivity (LI) in the plasma was measured by RIA during the intraintestinal oleate studies. CCK8 stimulated pancreatic enzyme secretion in a dose related fashion, an effect that was not modified by atropine. Intraintestinal oleate also stimulated pancreatic secretion and increased the CCK-LI in the plasma. Atropine significantly (p less than 0.05) decreased the pancreatic enzyme secretion before and during intraintestinal oleate, without effect on the CCK-LI levels. We conclude: (1) that the effect of exogenous CCK on pancreatic secretion of enzymes is not affected by atropine; (2) intraintestinal oleate stimulates pancreatic enzyme secretion significantly by an atropine-sensitive mechanism; (3) probably the atropine effect is a blockade of a cholinergic enteropancreatic reflex.

Adult↗
PubMed1983

Effect of intravenous lipid on human pancreatic secretion.

Parenteral alimentation, including intravenous fat, is sometimes used in the treatment of patients with pancreatitis, although the effect of intravenous fat on human pancreatic secretion has not been systematically studied. Intravenous fat, however, has been shown to stimulate pancreatic protein secretion in the dog. The purpose of these studies was to clarify the effect of intravenous fat on human pancreatic secretion. Pancreatic secretion was assessed by measurement of enzymes and bicarbonate in duodenal aspirate collected via a double-lumen tube from 6 healthy volunteers. Four studies were randomly conducted on different days. On day 1, graded concentrations of Intralipid (5%, 10%, and 20%) were given intravenously for 1 h each, while secretin (8.2 pmol . kg-1 . h-1) was given as a background. On day 2, the same doses of Intralipid were infused intravenously without secretin. On day 3, the same doses of Intralipid were perfused into the intestine, and, finally, on day 4, 20% Intralipid was given by intestinal infusion for 2 h while 10% Intralipid was infused intravenously during the second hour. Significant stimulation of enzyme secretion was observed only during the infusion of fat into the intestine, not after intravenous infusion at any concentration. Pancreatic enzyme secretion, stimulated by intraintestinal fat, was not significantly modified by simultaneous intravenous lipid infusion. We conclude that since intravenous fat does not stimulate pancreatic secretion, its use in conditions where pancreatic stimulation is undesirable appears safe.

Adult↗
PubMed1983

Impaired acid secretion and pancreatic polypeptide release in some patients with achalasia.

Achalasia is characterized by an intrinsic denervation of the esophagus. It is not known whether this process extends to other parts of the gastrointestinal tract. By means of the modified sham feeding test, we studied the innervation of the stomach and the pancreas in 13 patients with achalasia. We compared the results with those from a group of 15 healthy controls and a group of 10 vagotomized patients. We saw two patterns of response in the achalasia group: 6 patients secreted acid and released pancreatic polypeptide, as did the controls. The other 7 patients neither secreted acid nor released pancreatic polypeptide after modified sham feeding, as did the vagotomized patients. We conclude that some patients with achalasia have denervation of the stomach and pancreas, as assessed by the modified sham feeding test. These differences are unrelated to age, sex, and duration and severity of the disease or treatment. Interestingly, all patients who responded normally developed reflux esophagitis after dilatation. Besides being an interesting pathophysiologic observation, the response to modified sham feeding can help identify those patients at greater risk of developing reflux esophagitis after esophageal dilatation.

Adolescent↗
PubMed1982

Esophageal dysfunction in patients with mixed connective tissue diseases and systemic lupus erythematosus.

We sought to correlate esophageal symptoms with esophageal motility abnormality in 17 patients with mixed connective tissue disease (MCTD) and in 14 patients with systemic lupus erythematosus (SLE). Heartburn and regurgitation were common symptoms (11/17) in patients with MCTD, and most of the (10/11) exhibited significant manometric abnormalities. Additionally, impairment of esophageal peristalsis was found in four of the remaining asymptomatic patients. Severe esophageal aperistalsis was noted in nine MCTD patients. Patients with SLE also frequently reported esophageal symptoms (8/14), but significant motility abnormalities were seen in only three cases. In both patient groups good correlation between Raynaud's phenomenon and esophageal aperistalsis was found. Our results reveal that, although esophageal symptoms are commonly present in patients with both MCTD and SLE, severe esophageal motility abnormalities are more often found in patients with MCTD than in those with SLE.

Adult↗
PubMed1982

Pancreatic secretory response to sham feeding in humans.

We studied the pancreatic secretory response to sham feeding alone or during secretin infusion with and without administration of atropine in 10 human subjects. The magnitude of the response to sham feeding was compared to the response to cholecystokinin octapeptide. Sham feeding alone did not significantly increase pancreatic bicarbonate or amylase secretion above basal values. During a background secretin infusion, there was a significant increase of bicarbonate and amylase output (p less than 0.05) during sham feeding. The amylase response was approximately 50% of the maximal response to cholecystokinin octapeptide. In the tests with atropine and secretin, sham feeding still caused a significant increment in amylase and bicarbonate output. We conclude that (1) the pancreatic response to sham feeding is not clearly demonstrated without a background of secretin; (2) during secretin infusion sham feeding is a potent stimulant of pancreatic enzyme secretion, and (3) atropine had no significant effect on the pancreatic response to sham feeding under the conditions of this study.

Adult↗
PubMed1982

The effect of variations in intragastric pressure and gastric emptying of a saline meal in humans.

We have investigated the effect of variations in intragastric (IG) pressure on gastric emptying (GE) of a saline meal in six healthy subjects and six vagotomized patients. IG pressure was measured by an IG flaccid bag and GE by a marker. Studies were done during infusion of 0, 3, and 9 micrograms x kg-1 x min-1 dopamine without and after an injection of domperidone, a dopamine antagonist. Graded doses of dopamine decreased IG pressure and delayed GE emptying in both healthy and vagotomized subjects. A significant correlation was found between variations of IG pressure and GE. Both dopamine effects were antagonized by domperidone. These studies indicated that dopamine or its agonist and domperidone may be indicated in vagotomized patients with accelerated or delayed GE of liquids, respectively.

Adult↗
PubMed1981

Tiotidine, a new H2-receptor antagonist, is a potent inhibitor of nocturnal acid secretion in duodenal ulcer patients.

The efficacy of tiotidine, a new H2-receptor antagonist, in reducing nocturnal acid secretion of duodenal ulcer patients (N = 12, ages 21-60 years) was investigated. Different doses of tiotidine, 25, 50, 100, and 150 mg or placebo, were given as a single oral dose and acid secretion collected overnight. Tiotidine produced a significant, prolonged, and dose-related reduction of the nocturnal acid secretion without important side effects. The inhibition of cumulative H+ secretion after 25, 50, 100, and 150 mg tiotidine was 80, 89, 96, and 98% of that observed after placebo, while 300 mg of cimetidine caused an 87% inhibition. Compared to cimetidine, tiotidine appears to be approximately eight times more potent on a molar basis than cimetidine as an inhibitor of acid secretion, and the tiotidine effect is more prolonged. This strong and safe H2-receptor antagonist may be an important addition to the treatment of acid hypersecretory states.

Adult↗
PubMed1981

Sham feeding disrupts the interdigestive motility complex in man.

We have examined the effect of sham feeding on the interdigestive motility complex (IDMC) and the release of pancreatic polypeptide (PP) in a group of normal volunteers. The duration of the intervals in phase III of the IDMC was significantly delayed (p less than 0.01) after sham feeding, whereas there was an increase in plasma PP levels in all subjects. These results support the presence of an inhibitory vagal mechanism for the distal stomach and intestinal motility.

Adult↗