Biomedical subjects

S F Phillips

Publications and source records attributed to S F Phillips.

At least 163 records · Page 9Linked to original sources

PubMed1986

Anal and neorectal function after ileal pouch-anal anastomosis.

Bowel function varies markedly among patients with colectomy and ileal pouch-anal anastomosis. Little is known of the mechanisms controlling fecal continence and frequency of defecation after operation. The aim of this study was to determine which features of the anal sphincter and neorectum accounted for the variation in clinical outcome. Twenty patients were studied 4 to 35 months after operation and compared to 12 healthy volunteers. Despite several patients exhibiting impaired fecal continence, anal sphincteric length and pressures and ileal pouch capacity and distensibility were similar in patients and controls. Patients with poor results, however, had rapid filling of their ileal pouch, which resulted in early onset of high amplitude propulsive pressure waves in the pouch. As these waves became more frequent, defecation resulted. Patients with poor results also were not able to empty adequately their pouch. The poorer the completeness of evacuation, the more frequent the defecation (r = 0.62, p less than 0.01). The authors conclude that rapid pouch filling and impaired pouch evacuation can lead to increased stool frequency in patients after ileal pouch-anal anastomosis.

Adult↗

PubMed1986

Chenodeoxycholic and ursodeoxycholic acids alter motility and fluid transit in the canine ileum.

We examined the effects of chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA) on fasting motility patterns and transit in ileocolonic loops of 5 dogs. Animals were prepared with isolated loops (40 cm ileum and 5 cm colon) which maintained neuromuscular continuity with the intact bowel through a bridge of tunica muscularis. Myoelectrical activity was recorded from multiple serosal, monopolar electrodes and muscle contractions recorded from serosal strain gauges; fluid transit was assessed by continuous perfusion (1.4 ml min-1) of solutions containing polyethylene glycol 4000 marker, with or without bile acids. Saline perfusion did not disturb the fasting cycle of motility and mean cycle length in unperfused (106 +/- 7 min) loop was the same as during perfusion of saline (108 +/- 9 min). Bile acids abolished interdigestive cycles in 11 of 12 experiments, fasting patterns returned 64-106 min after bile acid perfusion was stopped. The fasting pattern continued to cycle normally in the proximal small bowel during bile acid perfusion. CDCA (15 mM) stimulated the occurrence of propulsive contractions of long duration. Bile acids shortened transit time through the loops and altered the pattern of flow towards a more continuous, steady stream. These effects of bile acids on ileal motility, like those described previously in the colon, could play a role in bile acid diarrhea.

Animals↗

PubMed1986

Ileostomy diarrhoea.

Proctocolectomy renders patients more prone to significant fluid and electrolyte disturbance due not only to the loss of the normal absorptive capacity of the colon, but also due to unique complications of the postoperative state. Other than causes of diarrhoea unrelated to ileostomy, ileal resection, partial small bowel obstruction, and regional enteritis represent the most common causes of ileostomy diarrhoea following conventional ileostomy. In addition, patients with intra-abdominal reservoirs are prone to develop a bacterial overgrowth syndrome. With reservoirs placed in a pelvic location, as part of an ileoanal procedure, defecatory frequency (with or without high faecal outputs) can also result from ineffective pouch evacuation, decreased pouch capacity or poor sphincteric function.

Bibliographies as Topic↗

PubMed1985

Anal sphincter electromyography after colectomy, mucosal rectectomy, and ileoanal anastomosis.

Electromyography (EMG) was used to evaluate the external anal sphincter in 27 patients following colectomy, distal mucosal rectectomy, and ileoanal anastomosis. The studies were conducted four months to 58 months (mean, 20 months) following the restoration of intestinal continuity. Nine patients underwent endoanal rectal mucosal stripping, while in 18 patients the rectum was everted to facilitate the stripping. Postoperative continence varied widely, from perfect to frequent and severe mucous of fecal leak. Abnormal motor-unit potentials were identified by EMG in nine patients and this finding was usually associated with poor continence. The sex of the patient, technique of mucosal stripping, and type of anastomosis did not influence the EMG result, but patients at least 40 years old all had abnormal EMGs. We conclude that poor continence after ileoanal anastomosis correlates with an abnormal EMG of the external anal sphincter. The cause of the EMG abnormality is unclear.

Adolescent↗

PubMed1985

Effects of morphine and atropine on motility and transit in the human ileum.

We examined motility of the ileocecal region, pressures at the ileocecal sphincter, and ileal flow after therapeutic doses of morphine and atropine. Using a factorial design in two cells of 8 (2(3] subjects, drugs were given during fasting and postcibally. Morphine (100 micrograms/kg body wt as a bolus intravenously) and atropine (7 micrograms/kg body wt as a bolus) stimulated migrating bursts of phasic activity (similar to phase III of the migrating motor complex). Morphine initially stimulated ileal flow, but atropine could not be shown to have this effect. Atropine reduced markedly the occurrence of sporadic pressure waves in the ileum, but morphine did not. Whereas atropine delayed mouth-to-ileum transit of polyethylene glycol, given in a mixed meal, morphine did not. Naloxone, in the dosage used (40 micrograms/kg body wt as a bolus, followed by 10 micrograms/kg body wt X h) had no independent effects on motility or flow, but did blunt the stimulatory effects of morphine and atropine on migrating motor complexes. We could not demonstrate an effect of any drug on the transit of lactulose from terminal ileum to cecum. Neither morphine nor atropine had impressive effects on tone at the ileocecal sphincter. These observations, while not specifying the mechanisms for constipation after opiates or anticholinergics, highlight the complexities of small bowel transit in humans and point out that the antidiarrheal effects of drugs are probably multifactorial.

Adult↗

PubMed1985

Motility of the small intestine after proctocolectomy and ileal pouch-anal anastomosis.

Though the mechanisms of continence after proctocolectomy and ileal pouch-anal anastomosis have been studied, functions of the small intestine have received little attention. However, frequent stools and urgency plague some patients who are otherwise quite continent. Motility of the jejunum and ileum was assessed in eight patients with ulcerative colitis who were studied 4 to 24 months after proctocolectomy and ileal pouch-anal anastomosis; these findings were compared to those in six healthy volunteers. Continuous manometric recordings from the small bowel were obtained in both groups for 16 to 23 hours of fasting; postprandial recordings were made for 6 hours following a mixed meal (800 kcal, 20% protein, 40% fat, 40% carbohydrate) in the ileoanal patients. The duration, velocity of propagation, and periodicity of the migrating motor complex did not differ between the groups (P greater than 0.05). Discrete bursts of clustered contractions were recorded from all of the controls and in five of eight patients. Likewise, we recorded from all controls and five of eight patients large amplitude, prolonged waves of pressure which propagated distally. However, in controls these large amplitude waves were confined to the terminal ileum, but in patients these were detected in the jejunoileum, up to 125 cm proximal to the ileal pouch. We conclude that jejunoileal motility is not greatly altered by proctocolectomy with ileal pouch-anal anastomosis. However, the appearance of the large amplitude, rapidly propagating waves in the proximal jejunoileum after operation may be a response to increased storage within and distention of the distal bowel.

Adult↗

PubMed1985

Contractile patterns and transit of fluid in canine terminal ileum.

Earlier recordings of intraluminal pressure from the terminal ileum and across the ileocolonic sphincter of dogs revealed, in addition to the usual interdigestive and digestive patterns, pressure waves that appeared to have propulsive potential. One of these, which we designated as a "prolonged propagated contraction" (PPC), was a wave of high amplitude; it had a duration much longer than the ileal slow wave and migrated rapidly through the ileum, often into the proximal colon. The other pattern was one of "discrete clustered contractions" (DCC); these were propagated bursts of rhythmic phasic waves, distinct from phase III of the interdigestive myoelectric complex. These migrated through the ileum more rapidly than did phase III. Our aims were to record the electrical and mechanical equivalents of these pressure events using only extraluminal sensors and to evaluate the capacity of these contractions to propel fluids. PPCs and DCCs were recorded by extraluminal strain gauges, and flow was assessed by recovery of a nonabsorbable marker. Phase III of the migrating motor complex propelled fluid through the ileum, but in addition DCCs and, especially, PPCs were able to empty the ileum. These latter contractions have similarities to the ileal "peristaltic rush" described by others, and we believe these waves are an important force for ileal emptying.

Animals↗

PubMed1985

Tone of canine ileocolonic junction: topography and response to phasic contractions.

We wished to define the physiology of the canine ileocolonic sphincter (ICS) and to examine function in relation to the region's anatomy. Prolonged recordings of tone at the ICS were made from seven dogs with isolated ileocolonic loops, and the effects of ileal and colonic distension on sphincteric tone were assessed. In acute experiments, pull-through pressures were measured at the ICS, and the location of the high-pressure zone was related to the region's anatomy. Basal tone at the ICS of approximately 30 cmH2O was confirmed; tone was augmented by colonic and ileal distension. The high-pressure zone was always centered on the anatomic ICS, but it extended into the adjacent ileum and colon for a total length of 2.0 cm (range 1.5-3.0 cm). Phasic contractions contributed to the maintenance of tone at the ICS, and a coordinated pattern of phasic contractions appears to contribute to the sphincteric properties of the region.

Animals↗

PubMed1985

Postoperative reflux gastritis: pathophysiology and long-term outcome after Roux-en-Y diversion.

Sixteen patients with clinical features of postoperative gastritis who had been advised to have a Roux-en-Y diversion were studied prospectively. Studies were done pre- and postoperatively (mean follow-up, 4.9 years; range, 3.8 to 6.9), and the findings were compared with those in 11 control subjects with previous enterogastric anastomosis but with no symptoms. The patients had higher concentrations of bile acids and trypsin in gastric samples than did controls. Patients had greater endoscopic changes, although mucosal histologic characteristics were similar in both groups. Administration of aluminum hydroxide or cholestyramine reduced the aqueous concentrations of bile acids in gastric contents. Roux-en-Y diversion virtually eliminated duodenogastric reflux, and gastroscopic appearances returned to normal. However, Roux-en-Y diversion did not change mucosal histologic characteristics. Symptom scores were reduced in the early postoperative period, but bilious vomiting was the only symptom alleviated consistently and permanently. As a treatment for postoperative gastritis, Roux-en-Y diversion offers potential but limited benefits.

Adult↗

PubMed1984

Functions of the large bowel: an overview.

The large intestine has been studied rather less than other portions of the alimentary canal for several reasons: a) considerable variations occur among species in the anatomy of the large bowel and in the absorptive contributions of the hindgut to homeostasis; b) in most species, the transit of colonic contents and the interactions between mucosa and contents are more complex than those occurring in the small bowel; and c) the existence of a rich microbial flora, which is of considerable importance ecologically, complicates the experimental approaches to colonic function and the interpretation of results. The colon possesses efficient mechanisms for sodium and chloride absorption, and an exchange of bicarbonate for luminal chloride is important. Absorptive function in the large bowel must also encompass the activities of faecal enzymes. By modifying faecal substrates, of both endogenous and exogenous origin, the flora facilitates and modifies absorption by the colon; in some species these events are important nutritionally. On the other hand, under pathophysiological conditions, the colon can secrete electrolytes and water. Storage and transit in the colon are also complex, relative to these phenomena in other areas of the gut. A major portion of the total mouth-to-anus transit time occurs in the colon, where to-and-fro movement of the contents is noticeable. Perhaps these complex movements facilitate absorption, by allowing optimum contact between contents and the mucosa. The colon also delivers material to the rectum in a manner whereby the distal bowel can prepare stools for convenient evacuation. Despite these difficulties, research is advancing our comprehension of the colon, its multiple and diverse functions and the possibilities for alterations of function leading to disease.

Animals↗

PubMed1984

Distinctive patterns of interdigestive motility at the canine ileocolonic junction.

Studies of interdigestive motor activity in the distal ileum, ileocolonic sphincter, and proximal colon were performed in two groups of dogs: (i) in those with ileocolonic loops that maintained neuromuscular continuity with the proximal intestine, we used an intraluminal side-hole assembly; (ii) in those with intact bowel, we attached extraluminal strain gauge transducers. Both groups of animals were equipped also with serosal electrodes. Positioning of motor sensors could be defined accurately by (a) a clear separation of rhythmic frequencies between those of the distal ileum (mean 10.8 cycles/min) and proximal colon (mean 6.2 cycles/min) and (b) the characteristic motor patterns of the ileocolonic sphincter. Analysis of motor activity in the segment demonstrated four distinct patterns: (i) irregular, apparently random phasic waves, (ii) rhythmic bursts of contractions corresponding to phase III of the migrating motor complex, (iii) other slowly propagated bursts of rhythmic activity (mean duration 3.6 min) recurring on average every 10 min, and (iv) single, prolonged (mean duration 16.7 s), high amplitude (mean 271 cmH2O) waves that propagated rapidly ("prolonged propagated contractions"). The latter two patterns appear unique to, or unusually prominent in, this region. A high degree of motor coordination between the distal ileum, ileocolonic sphincter, and proximal colon was also recognized. Thus, the patterns of motor activity suggest a specialized function for the distal 30 cm of ileum, the ileocolonic sphincter, and the proximal colon. These unique and coordinated patterns of motility deserve further exploration, especially in relation to ileocolonic transit and actions of the sphincter as a barrier to colo-ileal reflux.

Action Potentials↗

PubMed1984

Motility of the terminal ileum and ileocecal sphincter in healthy humans.

Factors controlling the transit of contents between the ileum and cecum should be important determinants of intestinal function; however, the dynamics of the ileocecal region remain largely unexplored in healthy humans. Accordingly, prolonged recordings of intraluminal pressure were obtained from the distal ileum, across the ileocecal sphincter, and from the proximal colon of healthy adults. In one set of studies, 16 subjects each contributed 6 h of basal, fasting recordings; in 2 of the 16, postprandial patterns were also recorded. In a second set, 6 fasting subjects were studied for a total of 120 h. Less than 10% of interdigestive cycles (migrating motor complexes) reached the ileocecal sphincter. The remainder faded out and merged into an active, apparently random pattern of pressure waves that became more intense closer to the sphincter. Discrete, short bursts of phasic pressures migrated rapidly for long distances in the distal ileum and a unique peristaltic wave also migrated rapidly, though infrequently, through the region. Tonic pressures were recorded across the ileocecal sphincter but were present only during the passage of phasic pressure waves; basal tone was minimal. We believe these are the first prolonged observations of motility from the ileocecal sphincter of healthy humans. These descriptions provide insights into and a basis for further studies of a largely unexplored area of the human bowel.

Action Potentials↗

PubMed1984

Longitudinal and radial variations of pressure in the human anal sphincter.

The pressure profile of the human anal canal integrates the effects of several separate muscles including internal and external and sphincters and the puborectalis. To define the topography of pressure along the anal canal, we developed a new probe that features four perfused side-hole channels spaced at 90 degrees circumferentially. In 18 healthy volunteers (10 women, 8 men), simultaneous four-quadrant pressures were measured at orad, mid-, and distal stations in the anal canal, at rest and during a maximum voluntary "squeeze." Anterior quadrant pressures were reduced significantly (p less than 0.001) at the orad station at rest and during maximum voluntary effort. In the midcanal, radial pressures were equal in all quadrants. Distally, pressures in the posterior quadrant were significantly lower than those in the other three quadrants. Men had longer sphincters than women, but men had higher pressures at the orad station only. Orad pressures were reduced in women who had had vaginal deliveries. We conclude that the human anal canal has marked, but consistent, radial and longitudinal variations of pressure. Based on these results, a structural and physiological explanation for their genesis is suggested. The findings may also be relevant to the development of cystoceles, rectoceles, and chronic anal fissures.

Adult↗

PubMed1983

Straight ileoanal anastomosis v ileal pouch--anal anastomosis after colectomy and mucosal proctectomy.

The postoperative results of 50 patients who underwent straight ileoanal anastomosis after total colectomy and mucosal proctectomy were compared with those of 74 patients who underwent ileal pouch--anal anastomosis. No deaths occurred. Of the straight ileoanal anastomoses, 32% failed because of sepsis or diarrhea and necessitated abdominal ileostomy; only 1.3% failed in the pouch-anal group (P less than .05). Stool frequency among patients followed up for three months or more (straight ileoanal, n = 30; pouch-anal, n = 33) was less in the pouch-anal group (mean +/- SEM, 7 +/- 1 stools per 24 hours) than in the straight ileoanal group (11 +/- 1/24 hr, P less than .01). Major nocturnal incontinence was also less in the pouch-anal group than in the straight ileoanal group (0% v 20%), and patient satisfaction was better, as measured on a scale of 1 (very poor functional result) to 10 (excellent result) (pouch-anal score, 9; straight ileoanal score, 6; P less than .02). We concluded that ileal pouch-anal anastomosis resulted in less diarrhea, better continence, and an improved quality of life when compared with straight ileoanal anastomosis.

Adult↗

PubMed1983

A continent ileostomy device.

The feasibility of achieving fecal continence by mechanical occlusion of an end-ileostomy is explored. Accordingly, progressive stomal occlusion with an indwelling occluding device was evaluated in four healthy patients with Brooke ileostomies. Pre-occlusion clinical and physiologic tests were done, including fat balance, intestinal transit time, ileal motility and absorption, ileal compliance, ileal radiography, and ileoscopy. Progressive stomal occlusion was then employed until periods of occlusion of 5 to 8 hours were achieved after 10 to 16 weeks. Pre-occlusion tests were then repeated. Patients mastered use of the occluding device rapidly, and the device achieved reliable stomal continence in each patient. Whereas ileal capacity was small initially, intermittent occlusion resulted in a large, capacious ileal reservoir. Fasting ileal motility was increased slightly by stomal occlusion, although intestinal transit during feeding was not altered. Also, ileal absorption of glucose, electrolytes, vitamin B-12, and fat were not changed, and ileal mucosa at the site of occlusion remained intact endoscopically. The authors concluded that chronic intermittent occlusion of a Brooke ileostomy with an indwelling stomal device achieved enteric continence without impairing intestinal function.

Adult↗

PubMed1983

A clinico-physiological comparison of ileal pouch-anal and straight ileoanal anastomoses.

The ileal pouch-anal anastomosis improves clinical results after colectomy and mucosal proctectomy compared to the straight ileoanal anastomosis. The question was what physiologic changes brought about by the pouch led to the improvement. Among 124 patients who had had ileoanal anastomosis, 25 volunteered for a detailed clinicophysiologic evaluation. Fourteen had had the ileal pouch-anal operation a mean of 8 months previously, and 11 had the straight ileoanal operation a mean of 25 months previously. Both groups of patients had satisfactory anal sphincter resting pressures (mean +/- SEM, pouch = 68 +/- 8 cm H2O, straight = 65 +/- 9 cm H2O, p greater than 0.05) and neorectal capacities (pouch = 278 +/- 26 ml, straight = 233 +/- 36 ml, p less than 0.05), and all could evacuate spontaneously. However, the pouch patients had a more distensible neorectum (delta V/delta P pouch = 9.5 +/- 1.3 ml/cm H2O, straight = 4.9 +/- 0.9 ml/cm H2O, p less than 0.05) and smaller amplitude neorectal contractions (pouch = 36 +/- 5 cm H2O, straight = 90 +/- 13 cm H2O; p less than 0.05). We concluded that the pouch-anal anastomosis increased the distensibility of the neorectum and decreased its propulsive drive, and so improved clinical results.

Adult↗

PubMed1983

Rapid intubation of the ileo-colonic region of man.

The relative inaccessibility of the ileo-cecal region of man has restricted study of, and limited the information available on, normal functions of this region. Intubation of the distal bowel from above may be slow, even in the presence of normal patterns of motility in the stomach and small intestine. This report documents that addition of a small balloon at the "lead-point" of the tube alters motor patterns and allows rapid transit to the colon.

Cecal Diseases↗

PubMed1983

Dysfunction of the continent ileostomy: clinical features and bacteriology.

The pathogenesis and treatment of dysfunction of the continent ileostomy was investigated in 12 patients, five of whom had asymptomatic malabsorption and seven of whom had acute complaints. The number of anaerobic bacteria in jejunal aspirates was increased in patients with pouch malfunction (range 10(3) to 10(8)/g aspirate), but the microbiology of ileal effluent and the morphology of the ileal mucosa could not be correlated with dysfunction. Bile acid breath tests and lactose tolerance tests were not, however, reliable indicators of jejunal bacterial overgrowth. The symptoms, the malabsorption, and the number of jejunal and ileal anaerobic bacteria decreased in patients during treatment with metronidazole, implicating overgrowth of anaerobic bacterial flora in the pathogenesis of the syndrome.

Adolescent↗