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Biomedical subjects

W J Hogan

Publications and source records attributed to W J Hogan.

At least 145 records · Page 8Linked to original sources
PubMed1982

Relationship of sphincter of Oddi spike bursts to gastrointestinal myoelectric activity in conscious opossums.

The oppossum sphincter of Oddi (SO) exhibits peristaltic spike bursts with accompanying contraction waves that originate proximally in the sphincter of Oddi and propagate toward the duodenum. In this study we recorded myoelectrical activity of the opossum SO and upper gastrointestinal tract in six conscious animals using chronically implanted electrodes. Biopolar electrodes were implanted in the gastric antrum, duodenum, SO segment, jejunum, and ileum. During fasting the frequency of SO spike bursts, scored as number per minute, showed a cyclic pattern consisting of four phases (A to D). Phase A had a low spike burst frequency of approximately 2/min that lasted approximately 20 min. In phase B, the spike burst frequency increased progressively during a 40-45 min interval culminating in a short interval of phase C activity characterized by a maximal spike burst frequency of approximately 5/min. During phase D, the spike bursts decreased over 15 min to merge with the low frequency of phase A and the cycle repeated. Cycle length of the interdigestive SO cycle, 87+/-11 SD min, was virtually identical with that of the interdigestive migrating myoelectric complex (MMC) of the upper gastrointestinal tract. The onset of phase C activity in the SO began 1-2 min before phase III of the MMC activity in the duodenum. Feeding abolished the cyclic pattern of spike burst activity in the SO as well as in the upper gastrointestinal tract. After feeding the SO spike bursts occurred at a frequency of 5-6/min for at least 3 h. We conclude that: (a) During fasting, the oppossum SO exhibits cyclic changes in its spike burst frequency; (b) Maximal spike burst frequency of the SO occurs virtually concurrent with passage of phase III MMC activity through the duodenum and; (c) Feeding abolishes the interdigestive cyclic spike burst pattern of the SO as well as that of the gastrointestinal tract.

Action Potentials↗
PubMed1982

Action of cholecystokinin-octapeptide on sphincter of Oddi basal pressure and phasic wave activity in humans.

The human sphincter of Oddi (SO) exhibits phasic wave activity over a 4 to 6 mm segment. Approximately 60% of these waves occur in an antegrade direction, 14% are retrograde, and 26% occur simultaneously. Because cholecystokinin-octapeptide (CCK-OP) stimulates the flow of bile into the duodenum, its effect on SO phasic wave contractions and contraction sequences was evaluated at ERCP manometry. An infused triple-lumen catheter of 1.7 mm outer diameter with side orifices spaced 2 mm apart was stationed in the SO segment so that all three orifices recorded phasic pressure waves. We studied 31 patients with normal ductal anatomy and normal SO pressures. In 21 of these patients CCK-OP (20 ng/kg) was given intravenously after a 2- to 3-minute baseline recording was obtained. Pressure recordings were continued for up to 10 minutes following CCK-OP administration. CCK-OP caused a significant inhibition in the frequency and amplitude of SO phasic waves as well as a significant decrease in basal SO pressure. Before CCK-OP most phasic contractions were antegrade, and after CCK-OP the sequence pattern remained unchanged. We conclude that CCK-OP reduces or transiently abolishes SO phasic contractions but that it does not change their temporal sequence. In addition, CCK-OP produces a decrease in basal SO pressure. These findings suggest that the action of CCK-OP in humans is to inhibit SO phasic activity and reduce SO basal pressure to allow increased flow of bile.

Ampulla of Vater↗
PubMed1982

Gallstone dissolution using mono-octanoin infusion through an endoscopically placed nasobiliary catheter.

Endoscopic sphincterotomy is widely being used for the treatment of common bile duct stones. In a small group of patients the gallstones are large in size and, hence, difficult to be extracted after a successful endoscopic sphincterotomy. We used a constant infusion of mono-octanoin through a nasobiliary catheter in nine such patients. This method was successful in partial or complete dissolution of the stones in 74% of the patients. In the remaining 36% of the patients, the stones were noted to be soft allowing easy extraction by crushing.

Caprylates↗
PubMed1981

Pharyngoesophageal motor function in patients with myotonic dystrophy.

Six adults with myotonic dystrophy underwent detailed radiological and manometric studies of pharyngoesophageal function. Four of the patients had no history of swallowing dysfunction, while two had very mild symptoms. All patients showed abnormalities of pharyngoesophageal function. Pharyngeal peristalsis was present but of low amplitude. Resting upper esophageal sphincter pressure was diminished, but the sphincter relaxed normally. Peristalsis in the esophageal body was invariably absent in the striated muscle segment of the esophagus and was either absent of decreased in amplitude in the smooth muscle segment. The lower esophageal sphincter was normal. Myotonia did not occur in the sphincters or the esophageal body. These findings suggest that pharyngoesophageal dysfunction is common in patients with myotonic dystrophy, even when clinical symptoms are absent. The abnormalities are probably related to muscle weakness rather than to myotonia in the pharyngeal and esophageal musculature.

Adult↗
PubMed1981

Esophageal function in esophageal atresia.

In order to determine the spectrum of esophageal dysfunction in repaired esophageal atresia, 14 patients were evaluated with esophageal manometry, intraluminal pH recording, and radiology. Nine patients had no difficulty in swallowing but six had symptoms suggestive of gastroesophageal (GE) reflux. On pH recording, six had evidence of GE reflux. Basal sphincter pressure was 22 mm Hg in both reflux and nonreflux patients. No patient had manometric evidence of peristalsis in the proximal esophagus, but six had peristalsis in the distal esophagus. On radiology all had a normal peristaltic stripping wave in the cervical esophagus, and peristalsis was absent in the proximal thoracic esophagus in all patients but present in the distal esophagus in five of the 10 patients studied. Esophageal dysfunction is present in all patients with repaired esophageal atresia even when symptoms are absent.

Adolescent↗
PubMed1981

Effect of atropine on esophageal motor function in humans.

In this study, we used a high-fidelity manometric recording system to quantitate the effects of atropine on lower esophageal sphincter (LES) pressure and primary peristalsis (1 degree P). A sleeve sensor recorded LES pressure, and seven recording orifices spaced at 3-cm intervals registered motor activity in the esophageal body. Five randomized manometric studies were done in each of five normal subjects. LES pressure and 1 degree P with wet swallows were recorded for 30 min before and 70 min after intravenous injection of saline or atropine, 3, 6, 12, and 24 micrograms/kg. We also studied the effect of atropine on LES pressure in five additional subjects, four dogs, four opossums, and six monkeys. In humans, saline and 3 micrograms/kg atropine caused no significant change in pulse rate, LES pressure, or the incidence of complete peristaltic sequences. The 6, 12, and 24 micrograms/kg atropine doses caused significant inhibition of LES pressure and the incidence of intact 1 degree P. Only the 12 and 24 micrograms/kg doses increased pulse rate. When 1 degree P occurred in the smooth muscle portion of the esophagus its appearance in the proximal portion of the smooth muscle segment was delayed for several seconds. The amplitude of 1 degree P was decreased 30-60% in the smooth muscle segment, but 1 degree P was not affected in the proximal striated muscle esophageal segment. Atropine reduced canine LES pressure substantially but caused no change in opossums or monkeys. We conclude that 1) basal LES tone in humans and dogs, unlike that of the opossum and monkey, is partially generated by cholinergic neural input, 2) cholinergic nerves elicit 1 degree P in human esophageal smooth muscle, and 3) species variation exists in esophageal responses to atropine.

Animals↗
PubMed1981

Effect of histamine on motor function of opossum sphincter of Oddi.

In this study, we evaluated the effect of histamine on phasic contractile activity in the opossum sphincter of Oddi (SO). SO manometry was done in 35 animals, using an infused catheter system with minimal compliance. In anesthetized animals, phasic SO contractions occurred at a frequency of 7.3 +/- 0.3 (SE) contractions/min with an amplitude of 83 +/- 4 mmHg. Intravenous histamine (5-80 micrograms/kg) invariably inhibited the frequency and amplitude of SO phasic contractions. At larger doses, the SO contractions were abolished for several minutes. The SO inhibitory effect of histamine was duplicated by the selective H1-agonist, 2-pyridylethylamine, and abolished by H1-blockade with pyrilamine or neural blockade with tetrodotoxin. After tetrodotoxin, histamine and 2-pyridylethylamine caused an increased frequency and amplitude of SO contractions. This excitatory effect was blocked by pyrilamine. The histamine effects on SO phasic contractions were not altered by metiamide, atropine, phentolamine, propranolol, hexamethonium, or a large dose of nicotine. We conclude that 1) histamine depresses phasic SO contractions in the opossum; 2) histamine's depressant SO effect is mediated by H1 stimulation of noncholinergic, nonadrenergic SO inhibitory nerves, overriding an H1 stimulatory effect on SO smooth muscle; and 3) histamine has no H2-mediated effect on the opossum SO.

Ampulla of Vater↗
PubMed1980

Mechanisms of gastroesophageal reflux in children.

We studied the lower esophageal sphincter in 29 children with known or suspected gastroesophageal reflux using a sleeve sensor and micro pH electrode. Mean lower esophageal sphincter pressure for a ten-minute monitoring period was 19 +/- 13 mm Hg; however, considerable temporal variation occurred in each child. Gastroesophageal reflex was infrequently associated with a low basal sphincter pressure (< 5 mm Hg) but usually associated with an increase in intra-abdominal pressure or with transient inappropriate relaxation of the lower esophageal sphincter.

Child, Preschool↗
PubMed1980

Endoscopic evaluation of inflammatory bowel disease.

The colonoscopic examination is not a routine procedure for patients with inflammatory bowel disease; colonoscopy does not supersede the double contrast barium x-ray examination as the diagnostic study of choice. The use of colonoscopy in patients with inflammatory bowel disease must be dictated by the particular clinical situation or nature of the problem and governed by the severity of colitis, the physical condition of the patient and the overall safety of the procedure in each instance. The judicious application of the colonoscopic examination in certain patients with inflammatory bowel disease yields important information concerning the nature, extent, and complications of the colonic inflammatory process, which heretofore has been unavailable for use in diagnosis and management of inflammatory bowel disease.

Colitis, Ulcerative↗
PubMed1980

Sandifer syndrome: an unappreciated clinical entity.

Five cases of Sandifer syndrome are reported, and the authors suggest that frequently the diagnosis may be overlooked, especially when the patient has a milder or incomplete form of the syndrome. None of the children had hiatal hernia, so this is not an essential requirement for the syndrome. The findings in these five cases suggest that the abnormal posturing associated with this syndrome may be the result of extreme sensitivity of the esophagus to refluxed gastric acid.

Female↗
PubMed1980

Effect of cholecystokinin-octapeptide on opossum lower esophageal sphincter.

We evaluated the action of cholecystokini-octapeptide (CCK-OP) on lower esophageal sphincter (LES) pressure in the opossum. LES pressure was recorded by an infused sleeve device that straddled the sphincter, whereas intraluminal esophageal pressure and gastric pressure were recorded via conventional manometric catheters. Progressive intravenous pulse doses of CCK-OP caused 1) graded increases in LES pressure, 2) circular and longitudinal smooth muscle contraction in esophageal body, and 3) mild increases in intragastric pressure. Pressor effect of CCK-OP on the LES was weakly antagonized by tetrodotoxin (TTX), but not by atropine, phentolamine, or pyrilamine. TTX antagonism of CCK-OP appeared to be nonspecific because TTX also partially antagonized LES contractions induced by pentagastrin, substance P, and bethanechol. We conclude that CCK-OP at doses that cause LES relaxation in other species induces LES contraction in the opossum. This pressor effect appears to be elicited by a direct action of the hormone on LES smooth muscle.

Animals↗