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Biomedical subjects

R C Arndorfer

Publications and source records attributed to R C Arndorfer.

At least 37 records · Page 2Linked to original sources
PubMed1986

Upper esophageal sphincter function during belching.

We studied the mechanism of belching with specific attention to the upper esophageal sphincter (UES) in 14 normal volunteers. Belching occurred by the following sequence of events: lower esophageal sphincter relaxation; gastroesophageal gas reflux, recorded manometrically as a gastroesophageal common cavity phenomenon; UES relaxation; esophagopharyngeal gas reflux; and restoration of intraesophageal pressure to baseline by a peristaltic contraction. Upper esophageal sphincter relaxations comparable to those associated with belches were induced by abrupt esophageal distention with air boluses. In contrast, fluid boluses injected into the midesophageal body either had no effect on UES pressure or increased UES pressure. Thus, the UES responded to esophageal body distention in two distinct ways: abrupt relaxation in response to air boluses and pressure augmentation in response to fluid boluses. Mucosal anesthesia did not alter the UES response to esophageal boluses of gas or liquid thereby making it unlikely that these substances are differentiated by a mucosal receptor. Rapid distention of the proximal esophagus with a cylindrical balloon (15 cm long) elicited UES relaxation. These findings suggest that the rapidity and spatial pattern of esophageal distention, rather than discrimination of the type of material causing the distention, determines whether or not UES relaxation occurs.

Adult↗
PubMed1986

Esophageal peristaltic dysfunction in peptic esophagitis.

Esophageal exposure to acid is a major determinant in the pathogenesis of reflux esophagitis. In this study, we analyzed the esophageal peristaltic function of 177 patients and asymptomatic volunteers for abnormalities that could lead to prolonged esophageal acid clearance. The subjects were divided into five groups: normal volunteers, patient controls, patients with noninflammatory gastroesophageal reflux disease, patients with mild esophagitis, and ones with severe esophagitis. Manometric data were analyzed for the occurrence of failed primary peristalsis, for the occurrence of feeble peristalsis in the distal esophagus, and for hypotensive lower esophageal sphincter pressure. From an analysis of the data on control patients, peristaltic dysfunction was defined as the occurrence of either failed primary peristalsis or hypotensive peristalsis in the distal esophagus for over half of the test swallows. Peristaltic dysfunction was increasingly prevalent with increasing severity of peptic esophagitis, occurring in 25% of patients with mild esophagitis and 48% of patients with severe esophagitis. A correlation did not exist between the occurrence of peristaltic dysfunction and hypotensive lower esophageal sphincter pressure (less than or equal to 10 mmHg). We conclude that peristaltic dysfunction occurs in a substantial minority of patients with peptic esophagitis and could contribute to increased esophageal exposure to refluxed acid material.

Adult↗
PubMed1986

Integrity of cholinergic innervation to the lower esophageal sphincter in achalasia.

The human lower esophageal sphincter (LES) is believed to be innervated by nonadrenergic, noncholinergic inhibitory nerves, and cholinergic excitatory nerves. In idiopathic achalasia, LES relaxation is abnormal because the inhibitory nerves to the sphincter are either absent or functionally impaired. The integrity of cholinergic excitatory nerves to the LES, however, has not been thoroughly evaluated. In 27 patients with untreated idiopathic achalasia, and 21 healthy volunteers, we investigated the hypothesis that postganglionic cholinergic nerves to the LES are functionally intact in achalasia. The LES responses to atropine, edrophonium, methacholine, amyl nitrite, and pentagastrin were assessed. In 2 achalasia patients, patterns of fasting motor activity in the LES were investigated during overnight manometric studies. Resting LES pressure was significantly greater in the achalasia patients, 41 +/- 4 mmHg (mean +/- SE), than in the normal subjects, 20 +/- 2 mmHg. Atropine significantly reduced LES pressure in both groups by 30%-75%. Edrophonium increased LES pressure in the achalasia patients but had negligible effect on the normal subjects. The LES in achalasia patients exhibited an increased sensitivity to both methacholine and pentagastrin compared with the normal subjects. In both patients who underwent an overnight manometric study, the LES exhibited cyclic phasic contractile activity synchronous with gastric contractions during the migrating motor complex. We conclude that the study findings support the hypothesis that postganglionic cholinergic LES innervation in achalasia patients is either normal or only minimally impaired, in contrast to the marked impairment of the inhibitory nerves governing LES relaxation.

Adult↗
PubMed1985

Multipeaked esophageal peristaltic pressure waves in patients with diabetic neuropathy.

We evaluated esophageal function in 14 consecutive insulin-dependent diabetic patients who had evidence of peripheral and autonomic neuropathy, but no esophageal symptoms. One to three contraction waves immediately followed a primary peristaltic contraction wave. The majority of these multipeaked pressure complexes consisted of two peaks. Multipeaked contractions were observed with all peristaltic waves in 12 of the 14 diabetic patients and with most of the peristaltic complexes in the remaining 2 patients. Multipeaked peristaltic waves were present in 1 of 6 diabetic patients without neuropathy, in 1 of 100 consecutive nondiabetic patients referred for suspected esophageal disease, and in 1 of 10 healthy volunteers. Double-peaked peristaltic pressure complexes in the nondiabetic control subjects differed from those present in the insulin-dependent patients by their low incidence and by a tendency to be limited to the distal esophagus. Pharmacologic responses to edrophonium and atropine suggested a possible increased cholinergic tone as the basis of the multipeaked peristaltic waves in diabetics with autonomic neuropathy.

Adolescent↗
PubMed1983

Motor function of the opossum sphincter of Oddi.

We studied the opossum sphincter of Oddi (SO) because in this species the SO is approximately 3 cm in length and its extraduodenal location permits recording of motor activity with negligible interference from duodenal motor activity. The SO segment of 120 animals was evaluated by one or more of the following: (a) intraluminal manometry; (b) electromyography; (c) common bile duct (CBD) flow monitored by a drop counter; (d) cineradiography of intraductal contrast medium; and (e) histologic examination. SO pull-throughs using an infused catheter of 0.6-mm o.d. invariably showed a high pressure zone (HPZ) of 18 +/- 3 SE mm Hg in the terminal 4-5 mm of the SO segment. This HPZ had a narrow lumen, 0.5-0.7 mm in diam, and prominent circular muscle. The HPZ in the terminal SO had both active and passive components. HPZ with minimal amplitude and a paucity of underlying smooth muscle were present inconstantly at the junction of the SO segment with the CBD and pancreatic duct, respectively. The dominant feature of the SO segment was rhythmic peristaltic contractions that originated in the proximal SO and propagated toward the duodenum. These contractions occurred spontaneously at a rate of 2-8/min, ranged up to 200 mm Hg in magnitude, had a duration of approximately 5 s and were not abolished by tetrodotoxin. Concurrent myoelectric and manometric recordings showed that each phasic contraction was immediately preceded by an electrical spike burst. Simultaneous recordings of cineradiography, CBD inflow of contrast medium, SO manometry, and SO electromyography indicated that rhythmic peristaltic contractions stripped contrast medium from the SO into the duodenum. During SO systole, CBD emptying was transiently interrupted, whereas SO filling occurred during the diastolic interval between SO peristaltic contractions. SO distention increased the frequency of SO peristalsis. We conclude that (a) the dominant feature of the opossum SO is rhythmic peristaltic contractions that originate in the proximal SO and propagate toward the duodenum; (b) these forceful SO peristaltic contractions are myogenic in origin and serve as a peristaltic pump that actively empties the SO segment; (c) CBD outflow occurs passively during SO diastole, but is interrupted transiently during each SO peristaltic contraction; and (d) a short HPZ with active as well as passive components exists in the distal SO segment and acts as a variable resistor to SO outflow.

Ampulla of Vater↗
PubMed1983

Interdigestive phasic contractions of the human lower esophageal sphincter.

The results of this study show that lower esophageal sphincter contractions occur during phases 2 and 3 of the gastric interdigestive migratory motor complex in humans. In one series of studies, esophageal, gastric, and duodenal pressures were monitored overnight for 12 h in 7 healthy, fasting subjects. A second group of 10 volunteers was studied for 12 h on two consecutive nights. Periods of gastric contraction that reached a maximum frequency of about 3/min were shown to be part of the migratory motor complex cycle because they occurred immediately before phase 3 migratory motor complex activity in the duodenum. In all subjects, gastric interdigestive contractions were accompanied by lower esophageal sphincter contractions that maintained a pressure barrier between the stomach and esophageal body. During late phase 2 and phase 3 gastric migratory motor complex activity, the lower esophageal sphincter contractions were especially vigorous. Mean basal lower esophageal sphincter pressure varied significantly during the interdigestive cycle. Lower esophageal sphincter pressure values were maximal during phase 3 of gastric migratory motor complex activity and minimal values occurred during phase 1. No episodes of gastroesophageal reflux occurred as a result of increase of intragastric pressure caused by interdigestive gastric contractions.

Adult↗
PubMed1983

Determinants of esophageal acid clearance in normal subjects.

In this study, we evaluated factors that affect esophageal acid clearance in normal subjects. A 15-ml bolus of 0.1 N HCl (pH 1.2) was injected into the esophagus, and the subject then swallowed every 30 s. Manometric and pH monitoring demonstrated that esophageal acid clearance occurred by a series of step increases in pH, each associated with a swallow-induced peristaltic sequence. Between peristaltic sequences, pH increase was minimal. Saliva stimulation by oral lozenge greatly improved acid clearance, while oral aspiration of saliva abolished the step increases in esophageal pH and markedly delayed acid clearance. Replacement of aspirated saliva with a bicarbonate solution reproduced the step increases in esophageal pH and restored acid clearance toward normal, while replacement with water alone failed to improve acid clearance. Similar to the effect of the oral lozenge, bethanechol (5 mg subcutaneously) improved esophageal acid clearance, but this improvement was reversed by oral aspiration of saliva, which markedly delayed acid clearance. A change from the recumbent to the sitting position tended to improve acid clearance slightly, but this improvement was not statistically significant. We concluded that in normal subjects (a) swallowing carries saliva into the esophagus and peristalsis empties intraesophageal fluid into the stomach, (b) the neutralization of acid by saliva carried into the esophagus with each swallow accounts for the occurrence of acid clearance by step increases in pH, (c) the improvement in acid clearance with bethanechol is due to saliva stimulation, and (d) gravity contributes little to esophageal acid clearance in the presence of normal peristaltic stripping waves.

Adult↗
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↗
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↗
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

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↗
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

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↗