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Biomedical subjects

W E Waterfall

Publications and source records attributed to W E Waterfall.

At least 19 recordsLinked to original sources
PubMed1989

The effect of glucagon on esophageal peristalsis and clearance.

The effect of 0.5 mg intravenous glucagon on esophageal peristalsis and transit of water and barium was studied in nine healthy subjects by concurrent videofluoroscopy and manometry. Glucagon lowered manometric peristaltic amplitude in both mid- and distal esophagus. This reached significance (p = 0.0075) in the distal 3 cm of the esophagus 2 min after the injection. The efficiency of esophageal stripping was also reduced (increased proximal escape on fluoroscopy), and became significant (p = 0.05) at 2 min after the injection of glucagon.

Adolescent↗
PubMed1988

Electrical correlate of circumferential contractions in human colonic circular muscle.

The role of myogenic electrical activity in the coordination of circumferential contraction of the human colon circular muscle was investigated. Five suction electrodes were placed (5-7 mm apart) on isolated rings of human colon and simultaneously electrical and motor activities were measured. In normal Krebs solution, the slow waves were not synchronised in most preparations studied. The electrical activities at the different recording sites were different with respect to slow wave frequency and amplitude, and amount of spiking activity. This resulted in irregular contractile activity. Cholinergic stimulation resulted in the development of a specific pattern of electrical activity: periodic slow wave activity with superimposed spiking activity which was synchronised over the length of the segment studied. This synchronised electrical activity resulted in regular phasic contractions at the frequency of the bursts of electrical activity (approximately 1/min). The response to carbachol was mediated by muscarinic receptors since it was blocked by atropine. The periodic activity in the continuous presence of carbachol was not the result of periodic input of neural activity as it occurred in the presence of TTX. Intrinsic properties of the muscle cells were responsible for the carbachol induced pattern of activity. The present study presents evidence that the electrical correlate of circumferential contractions is different in man compared with the most commonly studied animal models. It is a specific, stimulus induced pattern of myogenic activity. Its characteristics closely resemble those of a particular pattern of in vivo recorded activity referred to as the 'long spike bursts'.

Action Potentials↗
PubMed1986

Gastroesophageal reflux: clinical presentations, diagnosis and management.

Symptomatic gastroesophageal reflux occurs daily in an estimated 7% of adults and weekly or monthly in 29%. Untreated it can lead to esophageal erosions, ulceration and stricture formation. The pathogenesis is often multifactorial: defects in the function of the lower esophageal sphincter, esophageal clearance mechanisms and gastric emptying combine to produce frequent lengthy periods during which the lower esophagus is bathed in regurgitated acid. In most patients reflux disease is easily recognized as recurrent heartburn, regurgitation or dysphagia, or a combination. When acute chest pain or respiratory illness is the primary presenting complaint the patient needs particularly careful investigation to determine whether the symptoms are due to a primary cardiac or respiratory condition, are secondary to gastroesophageal reflux alone or represent a combination of disorders. Endoscopy with biopsy and long-term pH monitoring are the most reliable ways of determining whether reflux disease is present. Additional investigations, such as exercise testing, cardiac catheterization or inhalation challenge, may be needed in patients with cardiac or respiratory symptoms. Treatment should follow a stepped-care approach and in most patients should begin with changes in lifestyle, including dietary manipulation, reducing alcohol and cigarette consumption, and raising the head of the bed, together with appropriate use of antacids or alginate-antacid combinations. H2-receptor antagonists and agents to improve both gastric emptying and the tone of the lower esophageal sphincter may be added in sequence. Most patients will respond well to this regimen. Surgery should be considered only for those with intractable symptoms or with complications (e.g., stricture formation, bleeding, development of dysplastic epithelium in those with Barrett's esophagus, or secondary pulmonary disease that does not respond to medical management). It is successful in 85% of well-selected patients and has few complications.

Antacids↗
PubMed1984

Postanal repair to restore fecal continence after failed sphincteroplasty.

The traditional procedure of delayed repair of the sphincters and perineorrhaphy failed to restore continence to a 31-year-old woman who had fecal incontinence following obstetric trauma. Successful control was achieved by postanal surgical repair. This case report shows that good results are possible by reconstruction of the anorectal angle even after failed sphincteroplasty.

Adult↗
PubMed1983

Electrical patterns in the human jejunum with and without vagotomy: migrating myoelectrical complexes and the influence of morphine.

Postprandial symptoms that occur in some patients following operation for duodenal ulcer are generally attributed to disruption of normal controlled gastric emptying resulting from vagotomy, enterostomy, or pyloroplasty. The notion that disturbances of small bowel motility could be caused by vagotomy and contribute to these symptoms led the author to examine the myoelectrical patterns of the small intestine in duodenal ulcer patients undergoing elective surgery for control of symptoms. These patients underwent either partial interruption of their vagus nerves by proximal gastric vagotomy (PGV) or complete section by truncal vagotomy (TV). Their records were compared with those of an equal number of control subjects with intact vagus nerves undergoing laparotomy for either gallstones or colonic cancer. Postoperative recordings were obtained without sedation via electrodes implanted at laparotomy and led out of the abdomen through a drain in the right upper quadrant. Observations were made on days 6 through 9 after reestablishment of normal gastrointestinal function. Three patterns of electrical activity were recorded--electrical control activity, electrical response activity, and migrating myoelectrical complexes (MMCs). No observable differences were seen among PGV, TV, and control procedure during fasting or fed conditions. A key to an understanding of the origin of the MMCs was provided by the finding of disruption of the normal cycling of the complex by a premature cycle whenever morphine was given. Release of acetylcholine in the myenteric plexus of the intestine by an intrinsic opioid agonist may be the initiating event of the intrinsic MMC. Exogenous morphine may have caused a premature MMC by mimicking the stimulus produced by endogenous opioid. The morphine response was similar in persons with or without vagus nerves, suggesting that the initiation of cycling of the complex is entirely under local control of the intestine and not exercised through the parasympathetic division of the autonomic nervous system.

Duodenal Ulcer↗
PubMed1982

Effect of stress, meal and neostigmine on rectosigmoid electrical control activity (ECA) in normals and in irritable bowel syndrome patients.

An intraluminal probe with two sets of bipolar electrodes (4 cm apart) was used to record electrical control activity (ECA) from the rectosigmoid of 17 normal subjects and 16 IBS patients in the resting state, during neutral and stressful interviews, and after a meal or neostigmine. Fast Fourier transform method was used for the frequency analysis of ECA. The ECA was present at all times in both the groups but was variable in frequency and amplitude and was phase-unlocked during all recording periods. Up to four frequency components were observed in the lower frequency range (LFR) of 2.0-9.0 c/min and up to two in the higher frequency range (HFR) of 9.0-13.0 c/min during all recording periods. The frequency and organization of ECA were not significantly different between the normal and the IBS groups in the resting state. Neutral and stressful interviews did not significantly affect the mean ECA frequency in either of the groups but the mean ECA frequency of the dominant frequency component in LFR was lower in IBS patients than in the normal subjects during the stressful interview. Meal and neostigmine did not significantly affect the ECA frequency or its organization in either of the groups. It appears from this study that alternations in colonic ECA may not form the basis of motility disorder in irritable bowel syndrome.

Adolescent↗
PubMed1982

Electrical and contractile activities of the human rectosigmoid.

Electrical and mechanical activities were recorded from the rectosigmoid of normal subjects using an intraluminal recording tube with two sets of bipolar electrodes and strain gauges. Four distinct types of electrical activities were recorded. (1) Electrical control activity (ECA). This activity varied in amplitude and frequency over time and the control waves were not phase-locked. The means of dominant frequency components in the lower and higher frequency ranges were 3.86 +/- 0.18 SD and 10.41 +/- 0.46 SD c/min, respectively. The overall dominant frequency component was mostly in the lower frequency range of 2.0-9.0 c/min. (2) Discrete electrical response activity (DERA). This activity appeared as short duration bursts (less than 10 s) of response potentials whose repetition rate was in the total colonic electrical control activity frequency range of 2.0-13.0 c/min. The mean duration of this activity was 2.24 +/- 1.30 SD s. (3) Continuous electrical response activity (CERA). This activity appeared as long duration bursts (greater than 10 s) of response potentials which were not related to electrical control activity. Its mean duration was 14.78 +/- 3.68 SD s. This activity generally did not propagate. (4) Contractile electrical complex (CEC). This activity appeared as oscillations in the frequency range of 25-40 c/min and was also not related to electrical control activity. This activity propagated, sometimes proximally and sometimes distally. Its mean duration was 18.87 +/- 9.22 SD s. The latter three types of electrical activities were all associated with different types of contractions. These contractions, however, did not always occlude the lumen. Colonic electrical control activity controls the appearance of discrete electrical response activity in time and space. The mechanism of generation of continuous electrical response activity and contractile electrical complex is not yet known.

Adolescent↗
PubMed1981

Disorganised electrical activity in a child with idiopathic intestinal pseudo-obstruction.

This report presents the findings of investigation of a child with idiopathic intestinal pseudo-obstruction (IIP). Functional abnormalities of the smooth muscle of the gastrointestinal tract were disclosed by electrical recordings from the gut obtained after laparotomy. In vitro analysis of tissue and ultrastructure were undertaken and a possible aetiology of the disorder in this patient based on these findings is presented.

Action Potentials↗
PubMed1978

Benign oesophageal papillomatosis. A case report with a review of the literature.

An 18-year-old boy presented with a four-year history of dysphagia which had been treated repeatedly by endoscopic removal of papillomata of the oesophagus. Eventually, due to increasing dysphagia and repeated recurrences of the papillomata, resection of the affected lower third of the oesophagus was deemed necessary. The resected segment of the oesophagus was carpeted with numerous benign squamous papillomata. The clinical features, radiographic appearances, and pathology of this extremely rare tumour are presented. Only two acceptable cases of oesophageal papillomata can be found in the literature, making this the third case, and apparently the only one with multiple lesions.

Adolescent↗
PubMed1978

Idiopathic intestinal pseudoobstruction. Report of a case, with intraluminal studies of mechanical and electrical activity, and response to drugs.

Intraulminal recordings of motility were made from a patient with chronic idiopathic intestinal pseudoodstruction. Contractile activity was recorded from esophagus and duodenum with and without cholinergic stimulation. Electrical activity was recorded from duodenum with and without cholinergic stimulation. Contractile and electrical activities were recorded from the sigmoid colon at rest and after morphine. Gastric fundic relaxation was measured during balloon distention. This patient showed abnormalities of esophageal function similar to achalasia, while gastric fundic relation was impared, with a more rapid rise in pressure on distention than is seen in normal persons. Duodenal and colonic electric control and response activities were present on occasion. Duodenal contractions occurred in response to both bethanechol and edrophonium. Therefore, the efferent cholinergic system of the small bowel appears to be functional in this case of idiopathic intestinal pseudoobstruction. The nonardrenergic inhibitory control of esophagus and gastric fundus appears to be functioning abnormally.

Adult↗
PubMed1977

Myogenic and neural control systems for esophageal motility.

The role of myogenic and neural control systems in esophageal motility was studied in anesthetized opossums by applying electrical pulses at 20 to 40 v, and 100 to 400-msec pulse width directly to muscle layers, by cervical vagal stimulation (10 to 25 pulses per sec, 0.5 to 5-msec pulse width, 10 to 40 v), and by balloon distention. Direct muscle stimulation resulted in a propagated contraction in 13 of 22 opossums (proximal propagation from a distal stimulation site and vice versa). The velocity of propagation was of the same order of magnitude as that of a spontaneous swallow (less than 5 cm per sec). The propagated contractions were not blocked by intravenous or close intraarterial atropine and hexamethonium or by intraarterial tetrodoxotine. Smooth muscle depolarization by intraarterial KCl or tetraethylammonium brought about propagated contractions in those oppossums that did not show this in the first place. Generally, these propagated contractions could also be intiated in these opposums by applying 2 to 3 stimulating pulses 1 to 1.5 sec apart. The propagated contractions in response to direct muscle stimulation were observed in all opossums 2 to 20 min after death. Cessation of vagal stimulation and balloon relaxation produced "off-responses" which were blocked by tetrodotoxin. The propagation of off-responses was much faster than the swallow-induced peristaltic contractions. In conclusion, the myogenic control system in the esophagus is capable of producing propagated contractions independently which resemble normal esophageal peristalsis in propagation velocity, and may be the underlying system responsible for it. This system may, however, be modulated by the extrinsic and intrinsic nerves.

Animals↗
PubMed1973

The effects of varying the extent of the vagotomy on the myoelectrical and motor activity of the stomach.

The effects of varying the extent of vagotomy on the myoelectrical and motor activity of the stomach have been successfully studied in 21 patients undergoing either truncal, selective, or highly selective vagotomy for the treatment of chronic duodenal ulceration. The mean percentage time that regular antral myoelectrical activity was recorded preoperatively was 95.8% +/- 1.0 and this was decreased following highly selective vagotomy (74.0% +/- 6.6), selective vagotomy (37.8% +/- 12.4), and truncal vagotomy (30.2% +/- 10.4). The mean amplitude of the pacesetter potential was less following truncal (0.86 mV +/- 0.05), selective (1.32 mV +/- 0.09), and highly selective vagotomy (1.67 +/- 0.09) than in preoperative studies (2.21 mV +/- 0.12). Following truncal and selective vagotomies the triphasic waveform of the pacesetter potential changed to a sinusoidal shape. No significant change in the mean preoperative frequency of the myoelectrical activity (3.03 cpm +/- 0.08) occurred after vagotomy. Thus the changes in the electrical activity of the stomach are related to the extent of the vagal denervation. Intravenous administration of insulin did not alter these patterns except after highly selective vagotomy when the amplitude of the electrical waves, the incidence of action potentials, and percentage motor activity were increased.

Action Potentials↗
PubMed1973

The electrical and motor actions of gastrointestinal hormones on the duodenum in man.

The electrical and motor activity was recorded from the duodenum in 16 conscious human subjects in resting conditions. The main electrical wave form variously known as the pace-setter potential or slow wave was constantly present and periodically accompanied by a second electrical trace consisting of rapid bursts of fast waves or action potentials which were related to motor waves. Secretin and the synthetic analogue of gastrin, pentagastrin, were given in separate tests and their complementary actions on myoelectrical activity are reported. In general, secretin (in six subjects) depressed and pentagastrin (in eight subjects) enhanced motor activity and bursts of action potentials.

Action Potentials↗