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Biomedical subjects

W J Hogan

Publications and source records attributed to W J Hogan.

At least 163 records · Page 9Linked to original sources
PubMed1980

Mechanism of gastroesophageal reflux in recumbent asymptomatic human subjects.

We investigated the mechanism of gastroesophageal reflux (GER) in 10 health volunteer subjects. Continuous recordings of intraluminal esophageal pH and pressure were obtained on two consecutive nights from 6:00 p.m. to 6:30 a.m. in each subject. During each study, the subject remained recumbent, except to eat a standardized meal after 1 h of basal recording. A manometric assembly with seven recording lumens monitored: (a) lower esophageal sphincter (LES) pressure via a sleeve device 6.5 cm in length, (b) esophageal-body motor activity, (c) swallowing activity in the pharynx, and (d) gastric pressure. An electrode 5 cm above the LES recorded esophageal pH. Sleep was monitored by electroencephalogram. All subjects showed wide variations of basal LES pressure. GER was not related to low steady-state basal LES pressure, but rather occurred during transient 5-30 s episodes of inappropriate complete LES relaxation. The inappropriate LES relaxations were usually either spontaneous or immediately followed appropriate sphincter relaxation induced by swallowing. The majority of GER episodes occurred within the first 3 h after eating. During the night LES relaxation and GER occurred only during transient arousals from sleep or when the subjects were fully awake, but not during stable sleep. After GER the esophagus was generally cleared of refluxed acid by primary peristalsis and less frequently by secondary peristalsis. Nonperistaltic contractions were less effective than peristalsis for clearing acid from the esophagus. We conclude that in asymptomatic recumbent subjects GER is related to transient inappropriate LES relaxations rather than to low steady-state basal LES pressure and also, that primary perstalsis is the major mechanism that clears the esophagus of refluxed material.

Adult↗
PubMed1980

Intraluminal pressure recording from the human sphincter of Oddi.

In this study we recorded intraluminal pressure from the human sphincter of Oddi during ERCP examination and determined the effect of enteric hormones on sphincter of Oddi motor function. Studies were obtained in 26 patients who had no demonstrable evidence of pancreaticobiliary disease. After cannulation of the common bile duct (CBD) or pancreatic duct (PD), pressure measurements were made across the sphincter of Oddi (SO) during 1-2 mm incremental withdrawals of the catheter pausing 1 min or longer at each station. The findings showed an SO segment, 4-6 mm in length, that had basal, steady-state pressure about 4 mm Hg higher than CBD or PD pressure. Pronounced phasic contractions were superimposed on the basal SO pressure. These phasic contractions measured 101 +/- 50 SE mm Hg in amplitude and 4.3 +/- 1.5 sec in duration. They had a frequency of 4.1 +/- 0.9/min. Corresponding phasic contractions were not observed in the CBD, PD, or duodenum. Intravenous pulse doses of cholecystokinin octapeptide and glucagon depressed SO motor activity, whereas pentagastrin increased SO pressure. Secretin caused a mixed response of excitation followed by inhibition. We conclude that the human sphincter of Oddi demonstrates unique phasic contractions that are altered by enteric hormones given intravenously. These phasic SO contractions may have an important role in regulating biliary and pancreatic duct employing.

Adult↗
PubMed1979

Efficacy of the morphine-prostigmin test for evaluating patients with suspected papillary stenosis.

The morphine-Prostigmin test (MPT) has been advocated as a diagnostic test for identifying patients with papillary stenosis. We studied 14 patients referred for possible papillary stenosis with the MPT and ERCP sphincter of Oddi manometry. The response to the MPT (symptoms, serum amylase/lipase values) was evaluated by multiple criteria. The MPT was also done on 6 volunteer control subjects. Operative evaluation of the sphincter of Oddi was obtained in 8 of the 14 patients. There was no correlation between the results of the MPT and ERCP manometry or operative findings. There was good correlation, however, between ERCP manometric findings and operative assessment of the sphincter of Oddi. Fifty percent of the volunteer subjects had a significantly positive enzyme response to the MPT. In our experience the MPT does not reliably detect patients with papillary stenosis.

Ampulla of Vater↗
PubMed1979

Biliary and pancreatic duct pressures measured by ERCP manometry in patients with suspected papillary stenosis.

Papillary stenosis is an imprecisely defined clinical syndrome which eludes definitive diagnosis. In this study we evaluated 26 patients with suspected papillary stenosis by manometric examination of the sphincter of Oddi done during ERCP examination. Basal pressure in the sphincter of Oddi was elevated in 14 of the patients. Of these 14 patients, 10 underwent sphincterotomy and all experienced improvement in clinical symptoms after their surgery. We suggest that ERCP manometry is a useful procedure for identifying patients with papillary stenosis who may benefit from sphincterotomy.

Ampulla of Vater↗
PubMed1979

Desirability of roentgen esophageal examination immediately after pneumatic dilatation for achalasia.

Although infrequent, esophageal rupture is a serious complication of pneumatic dilatation for the treatment of achalasia. Because of an experience with delayed recognition of esophageal perforation in a patient with achalasia, we now examine the esophagus using a water-soluble contrast medium immediately following every pneumatic dilatation. This technique allows immediate detection of esophageal perforation.

Adult↗
PubMed1979

Depressant effect of sodium nitroprusside on the lower esophageal sphincter of the opossum.

In this study, we evaluated the effect of sodium nitroprusside (SNP), a vascular smooth-muscle relaxant, on lower esophageal sphincter (LES) pressure in the opossum. Resting LES pressure was monitored with a perfused sleeve sensor which allows accurate recording of LES pressure irrespective of axial LES motion. Intravenous pulse doses and infusion doses of SNP both caused significant decreases in both blood pressure and LES pressure. Les tone, however, was more sensitive to SNP than blood pressure. For example, an SNP pulse dose of 20 microgram/kg which lowered blood pressure only about 30% virtually abolished LES tone. A similar result was obtained for an SNP infusion dose of 10 microgram/kg/min. Tachyphylaxis to SNP did not occur for repeated pulse doses to 10 microgram/kg, but did develop during a 20-min infusion of 10 microgram/kg/min. The effect of SNP on LES pressure was not antagonized by propranolol, metiamide, haloperidol, atropine, phentolamine, or tetrodotoxin. We conclude that the potent depressant effect of SNP on LES tone is due to a direct action of the drug on sphincter smooth muscle.

Animals↗
PubMed1978

Responses of feline esophagus to cervical vagal stimulation.

We used an in vivo feline model to study striated and smooth-muscle esophageal responses to cervical vagal stimulation (VS). Circular esophageal contractions were measured by intraluminal pressure sensors and longitudinal contractions by a force transducer. Responses to VS were recorded before and after giving succinylcholine, atropine, or both. Circular contractions characteristic of striated and smooth muscle were recorded from the mid- and distal esophagus, respectively. With increases in VS frequency, the striated muscle showed rapid, repetitive twitches progressing to tetany. These fast contractions had a square-wave configuration at VS greater than or equal to 10 Hz and were abolished by succinylcholine. In contrast, the slow-twitch circular responses of smooth muscle showed no repetitive twitches and had a bell-shaped configuration. Two types of circular smooth-muscle contractions were observed: 1) A wave "on contractions" occurred 0.5-1.0 s after VS onset, regardless of stimulus length, and 2) infrequent B wave "off contractions" occurred only after stimulus cessation. The longitudinal esophageal contractions had a compound wave form with both striated and smooth-muscle components. Atropine abolished the slow component of the longitudinal contraction, the circular A wave, and peristalsis in the distal esophagus. We conclude that cholinergic motor neurons are an important pathway for eliciting peristalsis in feline esophageal smooth muscle.

Animals↗
PubMed1978

Efficient manometric technic for accurate regional measurement of esophageal body motor activity.

We have developed a single station, manometric recording technic that allows quick and accurate measurement of motor activity occurring in all regions of the esophageal body. The manometric instrumentation features a catheter recording assembly with eight recording orifices spaced at uniform 3 cm. intervals. Each recording lumen is infused with water by a minimally compliant hydraulic-capillary system which achieves accurate recording of peristaltic and nonperistaltic motor activity in the esophageal body at an infusion rate of 0.5 ml./min. Because the recording sites of the manometric assembly span a distance of 21 cm., a distance which approximates the length of the esophageal body in humans, a detailed map of motor activity over the entire length of the esophageal body is achieved by securing the manometric assembly at one suitable portion. Because frequent repositioning of the manometric assembly is eliminated, the method described takes only a few minutes for comprehensive assessment of esophageal body motor activity.

Esophagus↗
PubMed1977

A comparison of colonoscopy and roentgenography for detecting polypoid lesions of the colon.

This study compares the effectiveness of the roentgen and colonoscopic examination of the colon for detecting polypoid lesions. We evaluated the findings in 64 patients with suspected or known polypoid lesions who received the same colon cleansing regimen for both examinations, and were studied by examiners of similar expertise. As in other studies, the endoscopist had the advantage of knowing the roentgen findings, and the colonoscopic findings were often taken to indicate whether or not a lesion was present. In about half the patients, however, a second roentgen examination, repeat colonoscopy, or surgical specimen provided additional information for scoring. For example, a filling defect of the same size and location on two roentgen examinations, but not demonstrated at colonoscopy was scored as a false negative colonoscopic finding. The study results indicate that 54% of small polyps less than or equal to 0.9 cm in size were missed on roentgen examination, whereas no proven misses for lesions of this size were shown for colonoscopy. This absence of colonoscopic false-negative findings for small polyps, however, may be partially explained by a relative insensitivity of the roentgen method. For larger lesions greater than or equal to 1.0 cm in size the miss-rate for the two examinations was similar: 15% for roentgen examination and 12% for colonoscopy. We conclude: (1) Colonoscopy is a more sensitive method than roentgen examination for detecting small polyps of the colon, and (2) Performance of the two examinations may be comparable for demonstrating lesions 1.0 cm or larger in size.

Colonic Neoplasms↗
PubMed1977

Endoscopic electrosurgical papillotomy and manometry in biliary tract disease.

Endoscopic papillotomy was performed in 13 patients after cholecystectomy for retained or recurrent common bile duct calculi (11 patients) and a clinical picture suggesting papillary stenosis (two patients). Following endoscopic papillotomy, ten of the 11 patients spontaneously passed common bile duct (CBD) stones verified on repeated endoscopic retrograde cholangiopancreatography (ERCP) study. One patient failed to pass a large CBD calculus; one patient experienced cholangitis three months after in inadequate papillotomy and required operative intervention. Endoscopic papillotomy substantially decreased the pressure gradient existing between the CBD and the duodenum in all five patients studied with ERCP manometry. Endoscopic papillotomy is a relatively safe and effective procedure for postcholecystectomy patients with retained or recurrent CBD stones. The majority of CBD stones will pass spontaneously if the papillotomy is adequate.

Ampulla of Vater↗
PubMed1977

Effect of bethanechol on gastroesophageal reflux.

In this study we determined the acute effect of bethanechol (5 mg SC) on gastroesophageal reflux (GER) and lower esophageal sphincter pressure (LESP) in 27 patients with symptomatic esophagitis. The effect of bethanechol on esophageal acid clearance was also determined in 7 of the patients. Intraluminal pH monitoring prior to bethanechol administration demonstrated free or stress-induced reflux episodes in 18 of the 27 patients. Following bethanechol (1) LESP increased significantly, (2) GER diminished or ceased in many of the patients, and (3) acid clearance times decreased significantly. Some individuals, however, continued to reflux despite LESP elevation to 30 mm Hg or more. This latter finding suggests that LESP alone is not the sole factor governing LES competency. Other factors such as improved esophageal emptying may also contribute to the beneficial therapeutic effect of bethanechol in patients with heartburn.

Bethanechol Compounds↗
PubMed1977

Improved infusion system for intraluminal esophageal manometry.

An improved catheter infusion system is needed for esophageal intraluminal manometry. Using conventional syringe-pump infusion systems undesirably rapid infusion rates of 6 ml per min or more are often needed to achieve accurate recording of esophageal peristaltic pressure. These rapid base line infusion rates are necessitated by the high compliance of syringe-pump systems which causes substantial reduction in the infusion rate during dynamic pressure transients. In this study we tested a hydraulic-capillary infusion system designed to have low compliance. This minimally compliant system yields accurate recording of esophageal peristaltic pressure at infusion rates of 0.6 ml per min or less. We believe that the hydraulic-capillary infusion system is a useful tool for performing both clinical and investigative studies of esophageal motor function.

Adolescent↗