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S F Phillips

Publications and source records attributed to S F Phillips.

At least 127 records · Page 7Linked to original sources
PubMed1989

Human gastric emptying and colonic filling of solids characterized by a new method.

Our first aim was to compare 111In-labeled Amberlite IR-12OP resin pellets and 131I-labeled fiber in the assessment of gastric and small bowel transit and colonic filling in healthy humans. Both radiolabels were highly stable for 3 h in an in vitro stomach model and remained predominantly bound to solid phase of stools collected over 5 days [90.5 +/- 2.1 (SE)% for 131I and 87.4 +/- 1.4% for 111In). The lag phase of gastric emptying was shorter for 111In-pellets (30 +/- 11 min compared with 58 +/- 12 min for 131I-fiber, P less than 0.05). However, the slope of the postlag phase of gastric emptying and the half time of small bowel transit were not significantly different for 111In-pellets and 131I-fiber. Filling of the colon was characterized by bolus movements of the radiolabel (10-80% range, 26% mean) followed by plateaus (periods of no movement of isotope into colon lasting 15-120 min, range; 51 min, mean). Half of the bolus movements occurred within 1 h of the intake of a second meal. Thus 111In-labeled Amberlite pellets provide an excellent marker for the study of gastric and small bowel transit and colonic filling in humans. The ileum acts as a reservoir and transfers boluses of variable sizes into the colon, often soon after the intake of a subsequent meal.

Adult↗
PubMed1989

Rapid frequency rhythmic postprandial motility in the canine ileum.

We report here a novel motor phenomenon that we recorded from the canine terminal ileum in the postprandial period. In chronic models that allowed us to monitor myoelectrical activity and intraluminal pressure from the jejunum and distal ileum, we regularly saw in the ileum, but not in the jejunum, a rhythmic sequence of intraluminal pressure waves at a frequency of 19-24 cycles/min. This unusual motor pattern was rarely seen in the first 2 h after food and was essentially absent during fasting; it appeared reproducibly 1-4 h after food, at the time when chyme reached the ileum. The phenomenon was accompanied by spike bursts that were usually at the same rapid, rhythmic frequency, but the rate of the ileal slow wave persisted at the preprandial level (13-15/min). These findings further exemplify differences in the regulation of the motility between jejunum and ileum; moreover, the phenomenon highlights the capacity of the distal small intestine to response specifically to the nature of its luminal contents. This reaction of the ileum to the arrival of dietary residues is deserving of further study in the evaluation of the small bowel's response to a meal.

Animals↗
PubMed1989

Disorders of small intestinal motility.

This article reviews the pathophysiology of the disorders of small intestinal motility and the underlying diseases. These include pathologies that affect the whole gut wall, as well as those localized to the smooth muscle or neural elements. The principles of clinical evaluation and treatment are briefly discussed and possible future directions are suggested.

Animals↗
PubMed1989

Ectopic jejunal pacemakers and enterogastric reflux after Roux gastrectomy: effect of intestinal pacing.

The aims of this study were to determine whether ectopic pacemakers are present in the Roux limb of dogs after vagotomy and Roux gastrectomy, whether these pacemakers lead to enterogastric reflux, and whether abolishing the pacemakers with electric pacing might correct such reflex, were it to occur. In five dogs that had undergone gastric vagotomy and Roux gastrectomy and five dogs that had undergone gastric vagotomy and Billroth I gastrectomy (controls), myoelectric activity of the Roux limb or duodenum was recorded during saline infusion (154 mmol/L NaCl) or nutrient (Meritene) infusion into the limb or the duodenum. Reflux of infusate into the stomach was determined via a gastric cannula. Tests in Roux dogs were done with and without limb pacing. Roux dogs showed ectopic pacemakers in the Roux limb that drove the pacesetter potentials of the limb in a reverse, or orad, direction during 76% of the recordings; Billroth dogs rarely had such pacemakers (p less than 0.001). Enterogastric reflux occurred in both groups of dogs but was greater during phase III of the interdigestive migrating myoelectric complex in Roux dogs (12% +/- 6%) than in Billroth dogs (3% +/- 1%; p less than 0.05). Pacing abolished the ectopic pacemakers in the Roux dogs and reduced enterogastric reflux from 12% +/- 6% to 3% +/- 2% when phase III was present (p less than 0.05). In conclusion, the Roux limb was driven by ectopic pacemakers that contributed to, but were not solely responsible for, jejunogastric reflux. Pacing abolished the ectopic pacemakers and decreased reflux when phase III was present in the limb.

Action Potentials↗
PubMed1988

Use of profile analysis for the measurement of organ dimensions.

We have developed a method for measurement of organ dimension based on the use of the full width half maximum (FWHM) of profiles taken through an organ. In vitro studies were performed using a large rectangular lucite box filled with water. Five circular lucite phantoms with internal diameters of 1.4-10.2 cm and 1 elliptical phantom with dimensions 9.6 x 4.0 cm were filled with 99mTc-pertechnetate at various concentrations. Phantoms were imaged on a gamma camera at a depth of 5-25 cm in water and the FWHM calculated from horizontal profiles taken across the cylinders. The FWHM showed no variation with 99mTc concentration in the same cylinder. Phantom profiles were deconvolved with a system line spread function measured under similar conditions of scatter and depth. The correction factor to convert the deconvolved profile FWHM to true diameter was independent of cylinder depth and diameter over a range of FWHM 3-10 cm and depth 5-25 cm. The mean value for the correction factor was 1.23 +/- 0.04 for circular phantoms and 1.14 +/- 0.02 for the elliptical phantom. This technique should allow an objective and reproducible estimate of organ dimensions from planar images that is relatively independent of the depth and size of an organ.

Anatomy↗
PubMed1988

Reflux from ileum to colon in the dog. Role of external ligamentous attachments.

In four dogs we quantified the role of external ("coloileal") ligaments in preventing coloileal reflux. All animals were tested under control conditions, and then two had all external ligamentous attachments between ileum and colon divided; the other pair underwent a sham operation. Coloileal reflux was quantified scintigraphically at colonic pressures of 20, 40, and 60 mm Hg, and ileal motility was recorded concurrently. During control experiments and after sham operations, no dogs showed coloileal reflux at colonic pressures of 20 and 40 mm Hg. At a colonic pressure of 60 mm Hg, two control experiments and one in a dog after sham operation resulted in reflux of 9%, 4%, and 8% of counts, respectively. In contrast, both test dogs (after division of the ligaments) refluxed 30-70% of colonic content in all of four experiments at pressure below 20 mm Hg. In control dogs and in those with a continent ileocolonic junction, ileal motility consisted of scattered clusters of phasic contractions. In dogs with coloileal reflux, these clusters occurred with a similar frequency, but they lasted longer (P less than 0.005). Four weeks later, ileal motility indices in control dogs were significantly less (P less than 0.02) than in animals with divided coloileal ligaments. These observations establish an experimental model for coloileal reflux, support the hypothesis that external ligamentous attachments help maintain continence at the ileocolonic junction, and imply that coloileal reflux changes the motor pattern of the terminal ileum.

Animals↗
PubMed1988

Short-chain fatty acids stimulate ileal motility in humans.

We tested the hypothesis that short-chain fatty acids (SCFAs) and distention would stimulate ileal motility in humans. Intraluminal pressures in the ileocolonic region were recorded in 18 healthy human volunteers after instillation of boluses of SCFAs, air, and saline. Ileal motility was stimulated more often by SCFAs than by similar volumes of air or saline. Although increasing volumes of distention evoked greater numbers of contractions, this phenomenon was not apparent after repeated stimulation, suggesting that the "mechanoreceptor" in the human ileum has a refractory period. Symptoms of abdominal pain, cramps, and an urge to defecate may have resulted from instillation of SCFAs, even at small volumes. The motility stimulated in the ileum by SCFAs was not associated with systemic release of gastrointestinal regulatory peptides and was not affected by naloxone or indomethacin. Short-chain fatty acids, which can be considered as "markers" of colonic contents, might be associated with the motor response to coloileal reflux in humans.

Adult↗
PubMed1988

Campylobacter pylori and Barrett's esophagus.

Campylobacter pylori is thought to be confined to gastric mucosa; when detected in the duodenum in association with duodenal ulceration, the organism infects only areas of gastric metaplasia. Barrett's esophagus is a metaplastic condition of the esophagus, in which areas or islands of "gastric-type" epithelium are found. To determine whether C. pylori colonized the esophagus of patients with Barrett's esophagus, we studied retrospectively 23 unselected patients who had endoscopic and biopsy evidence of Barrett's esophagus. Mucosal biopsy specimens were stained by the Warthin-Starry silver technique and reviewed by an experienced, "blinded" histopathologist. Of the 23 patients, 12 (52%) had C. pylori in the esophagus. Patients with and those without C. pylori were of similar age and gender, had similar scores for acute and chronic inflammation, and had similar lengths of tubular esophagus with metaplastic gastric mucosa. These observations suggest that C. pylori commonly infects Barrett's esophagus. The clinical importance of this finding is unknown.

Adult↗
PubMed1988

Scintigraphic assessment of the anorectal angle in health and after ileal pouch-anal anastomosis.

To determine whether the anorectal angle was preserved after ileal pouch-anal anastomosis, a simple, safe, low-radiation, real-time method of imaging the anorectum was developed. A cylindrical balloon was placed in the neorectum and anal canal and filled with a solution of 99mTc in water. A gamma camera then imaged the angulation of the balloon while the subject was at rest, during sphincteric squeeze, and during a Valsalva maneuver. Thirteen healthy volunteers and six patients were studied after ileal pouch-anal anastomosis. An angle was identified in all controls and patients. In the lateral decubitus position at rest, the mean anorectal angle in controls (102 +/- 18 degrees; SD) and anopouch angle in patients (108 +/- 19 degrees) were similar (p = 0.3). Sitting straightened the angle in both groups (p less than 0.03), whereas sphincteric squeeze and a Valsalva maneuver sharpened the angle in both the sitting and standing positions (p less than 0.03). In the lateral decubitus position, however, the pouch group was less able to sharpen the angle than were the controls (p = 0.04). In controls, the anorectal junction descended during sitting and elevated during squeeze (p less than 0.03), but this did not occur in the pouch group. In conclusion, maneuvers favoring or stressing continence (squeeze, Valsalva) sharpened the anorectal angle and elevated the pelvic floor, whereas a maneuver favoring defecation (sitting) straightened the angle and caused the pelvic floor to descend. After ileal-anal anastomosis, the angle and its movements (except those while lying) were similar to controls. Elevation of the pelvic floor during squeeze, however, was decreased, indicating a decreased mobility of the pelvic floor after operation.

Adult↗
PubMed1988

Serotonergic regulation of canine enteric motility (measured as electrical activity) and absorption: physiologic and morphologic evidence.

To explore the effect of serotonin (5-HT) on enteric electrical activity, transit and absorption, four dogs were prepared with 50 cm jejunal and ileal Vella loops. Electrodes for recording enteric electrical activity were attached to the loops and to the main small bowel. After recovery, both loops were perfused with a [14C-]PEG-glucose-electrolyte solution via the proximal stomas, while effluent was collected from the distal stomas and enteric electrical activity was monitored. Control periods were compared with periods when 5-HT was infused intravenously at a rate of 10 micrograms kg-1 min-1 for 60 min. Serotonin increased the mean +/- SEM % of jejunal and ileal pacesetter potentials with spike potentials from 33 +/- 7% and 35 +/- 9%, before infusion to 63 +/- 4% and 61 +/- 5% after infusion (P less than 0.05). Serotonin also induced distally-migrating bursts of spikes in the incontinuity small bowel. The changes were blocked by atropine, but not by ketanserin. Absorption of water, sodium and glucose from the jejunal and ileal loop and transit through the loops was not changed by 5-HT. At autopsy, all layers of the jejunum and ileum contained varicose nerve fibres with a positive immunoreaction to 5-HT, while positive nerve cell bodies were largely confined to the submucosa.

Animals↗
PubMed1988

Epidemiologic aspects of Crohn's disease: a population based study in Olmsted County, Minnesota, 1943-1982.

The overall age and sex adjusted incidence of Crohn's disease among Olmsted County, Minnesota, residents was 4.0 per 100,000 person-year in the period 1943-1982. Ileitis, ileocolitis, and colitis each accounted for about one third of the 103 incidence cases. Incidence rates were greater in woman than men, were higher in the urban portions of the county, and rose over time. Overall, the natural history of Crohn's disease in the community may be milder than that reported for patients at referral centres, as over half of all patients had no complications and only a third required surgery for Crohn's disease. Only one developed adenocarcinoma of the colon (relative risk = 2.0, NS). Survival was relatively unimpaired for the cohort, but Crohn's disease may have played a role in half of the deaths. The prevalence of Crohn's disease was 90.5/100,000 population on 1 January 1980.

Adolescent↗
PubMed1988

Initiation of motility in canine ileum by short chain fatty acids and inhibition by pharmacological agents.

We have previously shown that short chain fatty acids (SCFA) stimulate motility in the canine ileum. Concentrations of SCFA in the ileum are normally low but would be expected to increase after coloileal reflux; thus, this phenomenon could have pathophysiological relevance. The present studies were designed to seek pharmacological means by which this response could be blocked. Four dogs were prepared with isolated, ileocolonic fistulae into which physiological concentrations of SCFA could be instilled so as to stimulate ileal motility. Pretreatment of the ileum with topical lidocaine abolished the response to luminal SCFA but general anaesthesia did not. Indomethacin stimulated ileal motility and prostacyclin abolished the ileal response to SCFA. Naloxone and a calcium channel blocker also negated the response to SCFA; blockage of muscarinic, adrenergic and 5H-T receptors did not. We conclude that the motor response to SCFA is probably a local neural reflex which is sensitive to local anaesthetics, opiates and the prostanoids.

Anesthesia↗
PubMed1988

Dysmotility of the small intestine in irritable bowel syndrome.

Though the pathophysiology of the irritable bowel syndrome (IBS) is commonly attributed to dysfunction of the large intestine, evidence exists to incriminate the small bowel. In order to further explore the role of the small bowel in IBS several stimuli were applied, in an attempt to unmask the dysmotility of the jejunum and ileum. These included infusions of cholecystokinin-octapeptide (CCK-OP), a high fat meal, neostigmine and balloon distension of the ileum. Three groups (n = 8) each of age and sex matched healthy volunteers were studied; patients with IBS complained of predominant constipation (n = 8) or diarrhoea (n = 8). Patients with IBS responded excessively to stimulation by CCK-OP, fatty meal, and ileal distension. In general patients with diarrhoea were more sensitive to stimuli than those with constipation. The ileum responded more to stimulation than the jejunum. As in the large bowel, stimuli appear to unmask intestinal dysmotility in patients with IBS. Motor abnormalities were often accompanied by abdominal symptoms, raising the possibility that dysfunction of the small bowel contributes to the symptoms of IBS.

Adult↗
PubMed1988

Non-ulcer dyspepsia: potential causes and pathophysiology.

Dyspepsia, defined as chronic or recurrent upper abdominal pain or nausea, is a common occurrence. Dyspepsia without an ulcer (non-ulcer dyspepsia) is diagnosed in patients at least twice as often as peptic ulceration. Diseases that may present with similar symptoms include gastroesophageal reflux, biliary tract disease, chronic pancreatitis, and irritable bowel syndrome. A careful history and physical examination, supplemented by selected tests, usually lead to a correct diagnosis. The pathogenesis of non-ulcer dyspepsia remains unknown. Gastric acid secretion, duodenogastric reflux, psychological factors, environmental exposures, and heredity probably do not play a major role. Some patients may have motility disturbances, but whether these disturbances cause dyspepsia is unknown. Campylobacter pylori infection and associated gastritis are common in non-ulcer dyspepsia, but their etiologic role is controversial, as is the importance of chronic duodenitis. By recognizing the heterogeneity of patients who present with non-ulcer dyspepsia, more rational management may be possible. Although an empiric trial of antacids or H2 blockers has been recommended to treat dyspepsia, most controlled trials show that although these substances reduce severity of symptoms, they are no more effective than placebos in non-ulcer dyspepsia.

Aerophagy↗