THE SIGNIFICANCE OF THE DIFFERENCE IN BACTERIAL ADHERENCE BETWEEN BLADDER AND ILEUM USING RAT ILEAL AUGMENTED BLADDER

OBJECTIVES: Intestinal segments are frequently used in the reconstruction of the urinary tract. Chronic bacteriuria is frequently observed in these patients, but the reason is not clearly understood. Therefore, we studied the difference in bacterial adherence between bladder and ileum using the rat ileal augmented bladder model to investigate the cause of chronic bacteriuria. MATERIALS AND METHODS: Augmentation of the bladder using ileum and a sham operation were performed under sodium pentobarbital in 102 and 10 Sprague-Dawley rats, respectively. At three months after the operation, urinary pH and plasma concentration of sodium, chloride and potassium were measured and urinary culture was done. Urovirulence factors of Escherichia coli aspirated from augmented bladder were detected by polymerase chain reaction (PCR). Five to six rats with negative urinary cultures after the augmentation were used for each experimental cystitis. E. coli with type I pili aspirated from augmented rats and three clinically isolated strains of E. coli, C5 (type I pili, aerobactin), C92 (type I pili, aerobactin, P fimbriae), and C189 (type I pili, aerobactin, P fimbriae, CNF), were transurethrally inoculated into the augmented bladder of rats. Fourteen days after inoculation, rats were sacrificed and colony-forming units (CFU) per mg. of tissue of bladder and ileum were measured. RESULTS: After operation, urinary pH and the serum level of chloride in all augmented groups were higher than those of the controls. Bacterial colonization was observed in 56 of 89 rats. Most of them were E. coli having only type I pili as a virulence factor. In contrast, the sham operated group revealed no bacterial colonization. In experimental cystitis, E. coli with only type I pili aspirated from augmented rats and E. coli C5 were clearly adhered to ileum rather than to bladder, but E. coli C92 and C189 showed no significant difference with respect to adherence to the two tissues. In experimental cystitis II, E. coli C5 with D-mannose were washed out in 3 of 5 rats by 14 days, while E. coli C5 without D-mannose were not washed out in all rats by 14 days. CONCLUSIONS: These results suggested that the difference in bacterial adherence due to urovirulence factors, especially type I pili, is one of the main causes of asymptomatic bacteriuria after urinary reconstruction.     

Calcium balance, growth and skeletal mineralisation in patients with cystoplasties.

Twelve adult female patients and 16 children who had undergone augmentation cystoplasty at least 2 years previously were studied to assess calcium balance and skeletal mineralisation. The serum and 24-h urinary calcium levels were measured and arterial blood gas analysis was performed in all patients. In children, skeletal mineralisation was assessed by serial study of their growth charts, comparing their growth centiles before and after cystoplasty. In adults, skeletal mineralisation was assessed by dual photon absorptiometry (DPA). As previously reported, all patients had a metabolic acidosis, usually with respiratory compensation. Serum and 24-h urinary calcium levels were all within the normal range. Growth charts of the 6 children with colocystoplasties showed an average of 20% reduction in growth potential in 3 of them. Growth charts in the 10 children with ileocystoplasties did not show any change in growth pattern. DPA bone scans in adults were all normal. These results suggest that if calcium is mobilised from bone in patients with a cystoplasty as a result of the metabolic acidosis, then it is reabsorbed from the bladder by the gut segment after an ileocystoplasty; colonic segments are less efficient than ileal segments, however, so that after a colocystoplasty skeletal demineralisation or a reduction in growth potential is more likely.     

Functional and urodynamic characteristics of bladder substitution with detubularised right colonic segment

A total of 19 patients underwent bladder replacement with a detubularised right colonic segment; 14 males underwent complete substitution after cystoprostatectomy and 5 females had augmentation after subtotal cystectomy. The mean follow-up time was 20 months. Urodynamic evaluation showed a low pressure reservoir with a mean capacity of 580 ml and normal closure pressure. Sensitivity of the bladder to cold was normal in the augmentation group but was lacking in all patients in the total substitution group. In all except 1 patient the neobladder emptied effectively upon straining without significant residual urine. Seventeen patients were completely continent by day and 10 by night; 1 patient developed hyperchloraemic acidosis requiring treatment. Bladder substitution is superior to the standard ileal or colonic conduits with regard to quality of life, and the use of a right colonic segment is functionally comparable with neobladders composed of the ileum or a combination of the right colon and ileum. The latter are more difficult to fabricate and so may have more complications.     

A juvenile animal model to study the growth potential of bowel segments in the urinary tract

A juvenile animal model has been developed to study the growth potential of ileum in the urinary tract. Patch ileocystoplasties of known surface area were constructed in dogs of Group 1. Nonrefluxing ileal nipple valves of known length were created to replace one ureter in dogs of Group 2. After the juvenile animals grew and at minimum doubled their weight, they were reoperated and augmentation surface areas were remeasured at various physiologic intravesical pressures. Nipple valve lengths were remeasured after cystograms ruled out reflux. Results show that the bowel augmentation and an identical control segment increased in surface area proportionate to animal growth and that hydrostatic dilation caused further surface area increase. Nipple valves did not grow and in fact shortened, but remained nonrefluxing. The conclusion is that in the pediatric population, consideration should be given to downscaling the size of bladder augmentations or diversions in anticipation of future bowel growth, but that one should not shorten the ileal nipple valves.     

The ileum neobladder--technic and results of bladder augmentation

Since April 1986, total bladder substitution (ileal neobladder) and bladder augmentation proved to be a reliable alternative method for urinary diversion in 81 patients. The operative technique is standardized, comparably simple and safe to prevent upper urinary tract deterioration, reflux, as well as incontinence. 11/81 patients (27-73 years, mean 52.5) underwent bladder augmentation (7 female, 4 male). 2/11 patients (1 female, 1 male) underwent undiversion (ileum conduit, neurogenic bladder). 10/11 patients are totally continent day and night. One female patient remained totally stress incontinent despite bladder neck suspension. Two female patients empty their bladder by intermittent catheterization.     

Functional and morphologic changes of the ileal mucosa after ileoanal pouch procedure

BACKGROUND: Restorative proctocolectomy is used widely for treatment of ulcerative colitis and familial polyposis coli. Limited information is available regarding the morphologic and functional adaptation of the mucosa in a functioning ileoanal pouch. STUDY DESIGN: Ileal pouch specimens from patients who underwent pouch reconstruction (mean 7.5 years postcolectomy, n = 12) were compared with normal ileum (n = 15) and normal colon (n = 5). Amino-oligopeptidase (AOP) and maltase activity were measured as parameters of normal ileal function. Histologic samples were examined for the presence of neutrophils and plasma cells, the villus to crypt height ratio, and the degree of crypt hyperplasia, villus blunting, and goblet cell mass. Data were analyzed by analysis of variance. RESULTS: The AOP activity in the normal ileum was 73 +/- 32 units of enzymatic activity per gram of mucosal protein; the AOP activities of the pouch and colon were 21 +/- 22 and 16 +/- 10, respectively. The maltase activity of the normal ileum measured 254 +/- 116 units of enzymatic activity per gram of mucosal protein, and the maltase activities of the pouch and colon were 57 +/- 71 units and 29 +/- 25 units, respectively. The ileal pouch mucosa demonstrated little acute inflammation and varying degrees of chronic inflammation. Morphologically, the ileal pouch mucosa demonstrated a range of adaptations, including villus blunting and crypt hyperplasia. Several specimens contained immature epithelial cells. CONCLUSIONS: The AOP and maltase activities in mucosa from ileoanal pouches and colon were significantly lower than those in normal ileal mucosa. Ileoanal pouch mucosa from humans undergoes adaptive changes to resemble colonic mucosa both morphologically and functionally.     

The Mainz pouch (mixed augmentation ileum and cecum) for bladder augmentation and continent diversion

The surgical technique for construction of the Mainz (mixed augmentation ileum and cecum) ileocecal pouch for bladder augmentation or continent urinary diversion focuses on 3 functional features: creation of a low pressure reservoir of adequate capacity from cecum and 2 ileal loops, which are split open longitudinally, antirefluxing ureteral implantation into cecum or ascending colon, achieved by a standard submucosal tunnel technique, and in cases of bladder augmentation continence depends on competence of the bladder neck and urethral closure mechanisms, while in urinary diversion continent closure of the pouch is achieved by isoperistaltic ileoileal intussusception or implantation of an alloplastic stomal prosthesis. Of 11 patients with Mainz pouch bladder augmentation (5 of which were undiversions) 10 are completely dry day and night with normal intervals of bladder evacuation. Two patients with myelomeningocele are on intermittent catheterization for bladder evacuation, while the remainder void spontaneously without significant residual urine. Of 12 patients with Mainz pouch urinary diversion 6 have an ileoileal intussusception valve and are completely continent, as are 3 of 4 with an alloplastic stomal prosthesis. Two patients still are awaiting implantation of a sphinteric prosthesis.     

Comparison of muscarinic cholinergic and alpha adrenergic receptors in canine ileum, colon, intestinal urinary reservoirs and bladder

The muscarinic cholinergic (MCh) and alpha 2 adrenergic receptor densities in canine ileum, colon, ileal and colonic urinary reservoirs and bladder were determined using radioligand receptor binding methods in order to provide a rational basis for pharmacologic management of urinary incontinence following bladder replacement with intestinal segments. Muscarinic cholinergic and alpha 2 adrenergic receptor binding sites were studied in these tissues using saturation experiments with 3H-NMS and 3H-rauwolscine, respectively. The mean equilibrium dissociation constants for 3H-NMS binding (0.13 to 0.17 nM) in these tissues were similar (p greater than 0.05) indicating homogeneity of muscarinic cholinergic binding sites. The mean equilibrium dissociation constants for 3H-rauwolscine binding (1.27 to 1.98 nM) in these tissues were also similar (p greater than 0.05). A substantial density of MCh (1.06 to 1.22 fmol/mg. wet wt.) and alpha 2 adrenergic (0.47 to 1.11 fmol/mg. wet wt.) binding sites was identified in the intestinal tissues assayed. The density of ileal and colonic MCh and alpha 2 adrenergic binding sites was not altered following construction of urinary intestinal reservoirs. The presence of a substantial density of MCh and alpha 2 adrenergic binding sites in the intestinal tissues suggests that MCh and alpha 2 adrenergic analogs may be utilized for the management of urinary incontinence following bladder replacement with intestinal urinary reservoirs.     

Experience with demucosalized ileum for bladder augmentation

OBJECTIVE: To assess the use of demucosalized ileum for bladder augmentation, following the same principles previously used with the sigmoid colon. PATIENTS AND METHODS: Eleven patients with bladder exstrophy or a neurogenic bladder had their bladders augmented with demucosalized ileum instead of the sigmoid colon, but following the same technique. The use of a Foley catheter with an inflated balloon greatly facilitated the dissection of the mucosa from the muscle. A silicone model, inserted in the bladder, was used to avoid shrinkage of the patch. An animal model was also used for total bladder replacement following the same principle. RESULTS: The mean (range) follow-up was 15.4 (2-25) months. There was a significant increase in bladder compliance in all patients. A bladder of good shape and compliance was obtained in the animal model, with epithelial growth detected in all cases. CONCLUSIONS: Demucosalized ileum can be used safely for bladder augmentation in the same way as with the sigmoid colon. The distension of the isolated patch greatly facilitates dissection between the mucosa and muscle. The animal model supported this method of bladder replacement.     

Improvement of ureteroileal anastomosis in orthotopic ileal neobladder with modified le duc procedure: short submucosal tunnel technique

PURPOSE: A modified Le Duc procedure with a short submucosal tunnel was applied for ureteroileal implantation in ileal orthotopic neobladder and bladder augmentation with the ileum. We assessed the rate of stenosis and ureteral reflux at the ureteroileal anastomosis after this procedure. MATERIALS AND METHODS: Two women and 22 men underwent radical cystectomy and creation of a Hautmann ileal neobladder for invasive bladder cancer. Another woman underwent ileal bladder augmentation with bilateral ureteral reimplantation into the ileal segment. Ureteroileal anastomosis was performed using the modified Le Duc technique in 48 renoureteral units. Followup in all patients included retrograde cystography done before discharge home and excretory urography, renal ultrasonography or abdominal computerized tomography every 4 to 6 months. Followup was 11 to 39 months in 23 of the 25 cases. RESULTS: Retrograde cystography before discharge home revealed no urinary reflux in any reimplanted ureter. There was no ureteral stenosis or reflux in 20 male and 3 female patients (44 renoureteral units) who voided successfully without catheterization. A unilateral ureteral stricture at the ureteroileal anastomotic site in 1 man who voided successfully was treated with endoscopic surgery. Bilateral slight upper urinary tract dilatation caused by ureteral reflux was present in another man who did not void successfully. CONCLUSIONS: The modified Le Duc technique is simple and safe for forming an ureteroileal anastomosis in ileal orthotopic neobladder creation. It appears to have a low ureteral stenosis and reflux complication rate in patients who successfully void postoperatively.     

Reconstruction of urinary bladder

Reconstruction of the urinary tract was reviewed. Reconstruction of the ureter dealt with end to end ureteroureterostomy, transureteroureterostomy, bladder flap procedure, psoas hitch procedure, ureterovesiconeostomy, ileal inter position and autotransplantation of the kidney. Bladder augmentation concerned with use of the ileum, ileocecal segment and sigmoid colon, together with artificial material. Reconstruction of the bladder included urinary diversion such as ileal, jejunal, sigmoid, transverse and ileocecal conduit, ureterureterostomy, continent urinary reservoir such as Kock, Mainz and Indiana pouch, and total replacement of the bladder using various segments of intestine anastomosed to the urethra. Surgical endeavor performed by urologists during the past 100 years from 1890 to 1990 was tremendous and it was mainly reviewed from the standpoints of surgical technique and complications.     

Multilayered small intestinal submucosa is inferior to autologous bowel for laparoscopic bladder augmentation

PURPOSE: Bladder augmentation is most commonly performed with ileum. However, porcine small intestinal submucosa has been reported as a substitute for bowel for incorporation into the urinary tract. We assessed the feasibility and long-term 12-month results of laparoscopic bladder augmentation with ileum or multilayered small intestinal submucosa (Cook Biotech, Spencer, Indiana) in a porcine model. MATERIALS AND METHODS: We performed laparoscopically assisted hemicystectomy and bladder augmentation in 24 female Yucatan mini-pigs using an ileal segment (12) or multilayered small intestinal submucosa (12). The followup protocol included anesthetic bladder capacity, renal ultrasonography and serum chemistry. At 3, 6 and 12 months, respectively, 4 animals per group were scheduled for sacrifice and pathological analysis. RESULTS: Despite longer anastomotic time in the multilayered small intestinal submucosa group (120 versus 91 minutes, p = 0.026) total operative time was similar in the 2 groups. In each group bladder capacity increased with time but by 12 months bladder capacity was significantly better in the bowel than in the small intestinal submucosa group (825 versus 431 cc, p = 0.016). At 3 months pathological evaluation revealed that the multilayered regenerated bladder patch had shrunken and by 6 months it was replaced by dense calcified scar tissue. Long-term 6 and 12-month bladder capacity in the small intestinal submucosa group was the result of the regeneration of native bladder with exclusion of the whole multilayered patch in the majority of cases. CONCLUSIONS: Laparoscopic bladder augmentation using multilayered small intestinal submucosa produced functional and pathological results inferior to those of bowel at 12-month followup in a porcine model.     

Influence of urological irrigation fluids on urothelial bacterial adherence

Summary The influence of various urological irrigation solutions on bacterial growth and adherence to urothelium was investigated in in vitro and guinea pig models. The irrigation solutions glycine 1.5%, glycine 1.5% and ethanol 1%, glycerol 3%, mannose 6%, sorbitol 2.7% and mannitol 0.54% all inhibited bacterial growth compared with normal saline. In guinea pigs, the influence on bacterial adherence of four irrigation solutions (glycine 1.5%, glycine 1.5% and ethanol 1%, mannose 6%, povidone-iodine) was investigated using two different strains of E. coli. After cauterizing one side of the bladder and inoculation with 2.7×10⁸ colony forming units under high or low pressure, the bladder was irrigated with the irrigation solutions. There was a stronger adherence of E. coli O6 (with type I pili) than of E. coli ATCC 25922 (without type I pili) to bladder urothelium, particularly to the injured side. There was no significant difference between the high- and low-pressure groups. None of the various irrigation solutions was clearly superior. As mannose 6% effectively inhibited type I pili and also had some antibacterial activity it may reduce urinary tract infection if used as irrigation solution.     

The Mainz pouch. Ileocecal reservoir, Mainz pouch

The surgical technique for creation of the Mainz-pouch uses 12cm of cecum and ascending colon and 2 ileal loops of the same length for construction of an urinary reservoir, which has proven to be applicable for bladder augmentation, bladder substitution as well as for continent urinary diversion. For the creation of a continent nipple in urinary diversion 6cm of ileum in addition are necessary. As a modification we use the non-infected submucosal imbedded appendix as continence mechanism. Since 1986 a total of 247 patients underwent a Mainz-pouch procedure: 54 for bladder augmentation, 27 for bladder substitution and 166 for continent diversion. The appendix as continence mechanism was used in 30. Postoperative mortality rested under 1%, early complications have been observed in 4.4% and late complications in 13.7% (mean follow-up of 35 months). In the bladder augmentation group 52 patients are completely dry, 2 patients have urge and frequency and 5 patients are on intermittent self catheterisation to avoid residual urine. In the bladder substitution group all patients are continent at daytime. At nighttime 3 patients have leakage if they don't empty their bladder all 4 hours. In the urinary diversion group all but 3 are completely dry and are on intermittent catheterization. The main problem of our initial series was prolapse of the continent nipple which has been solved by staple fixation of the nipple to the bowel wall and to the ileocecal valve or by using the submucosal imbedded appendix.     

TRANSVERSE RETUBULARIZED SIGMOIDOVESICOSTOMY CONTINENT URINARY DIVERSION TO THE UMBILICUS

PURPOSE: The most widely used conduit when creating continent urinary diversion based on the Mitrofanoff principle has been appendicovesicostomy. However, appendix is not always available and it is increasingly used for the antegrade continence enema in situ appendix procedure. In 1993 the technique of transverse retubularization of the ileum to create a continent catheterizable conduit for an ileal reservoir was described and in 1997 this technique was studied in an animal model. Larger patients may need 2 ileal segments in series to bridge the distance between the umbilicus and bladder. To avoid using 2 segments we used transverse retubularized sigmoid colon to create a catheterizable sigmoidovesicostomy to the umbilicus. METHODS AND METHODS: In 5 children 6 to 19 years old (mean age 15) with neurogenic bladder secondary to spina bifida a transverse retubularized sigmoidovesicostomy to the umbilicus was performed. In all patients an antegrade continence enema procedure was done for refractory constipation and overflow fecal incontinence secondary to neurogenic bowel. Laparoscopy was performed to mobilize the appendix in patients who requested a low Pfannenstiel incision for better cosmesis. Additional procedures included the pubovaginal sling placement and sigmoid colocystoplasty. RESULTS: Mean length of the sigmoidovesicostomy, which was equal to the circumference of the sigmoid before retubularization, was 13 cm. (range 10 to 15). This sigmoid conduit reached the umbilicus easily in all cases. All sigmoidovesicostomies were easily catheterized and all were continent. One patient with morbid obesity (body mass index 40.4) had a mucocutaneous anastomotic breakdown 3 months postoperatively. Minimum followup was 1 year (mean 1.5). CONCLUSIONS: Transverse retubularized sigmoidovesicostomy is effective for creating a continent urinary diversion to the umbilicus in patients with neurogenic bladder secondary to spina bifida. Dilating the sigmoid colon from neurogenic bowel creates a long conduit based on the Yang-Monti principle and 2 ileal segments with an anastomosis are not required. Additional benefits are that the sigmoid colon is readily accessible via a low Pfannenstiel incision and may also be used for augmentation in select cases.     

Functional characteristics of the continent ileocecal urinary reservoir: mechanisms of urinary continence

We evaluated urodynamically 14 patients with a continent ileocecal urinary reservoir. Reservoirs were constructed of detubularized right colon alone (4 patients), or augmented with ileum (2) or with a U-shaped ileal patch (8). All reservoirs were placed in the abdomen and used plicated terminal ileum as the efferent continence mechanism. Twelve patients are completely continent with intermittent catheterization at 4 to 8-hour intervals. Two patients suffer mild nighttime incontinence. Mean reservoir volume was 675 ml. Intermittent intestinal contractions were noted in the plicated ileal segment and reservoir but they occurred more frequently in the former and were either synchronous with or preceded those in the reservoir. Mean and maximal contraction pressures were 24 and 47 cm. water, respectively, in the reservoir and 40 and 151 cm. water, respectively, in the plicated ileal segment (p equals 0.043 and less than 0.001, respectively). The highest reservoir contractions occurred in the 2 patients with nocturnal incontinence. The method of construction bore no consistent correlation with mean or maximal contraction pressures, contraction frequency or continence. Careful urodynamic assessment suggests that the ileocecal urinary reservoir is a relatively low pressure, nonrefluxing and continent bladder substitute. The plicated terminal ileal segment acts as an effective sphincter that responds to pressure elevations in the reservoir. Its simple construction and easy catheterization make it an attractive alternative to intussuscepted ileal segments.     

Editorial

ABSTRACT

Twenty-four patients, with various combinations of non-healing decubitus ulcers, urethral fistulae, incontinence, and penile skin breakdown were candidates for proximal urinary diversion, having failed intermittent, external, and indwelling catheterization combined with pharmacologic therapy. Seventeen patients underwent bladder neck closure, including seven with multiple sclerosis and ten with spinal cord injury, and because they were unable or unwilling to do catheterization, had their urine diverted by suprapubic catheter. Seven patients, including four with spinal cord injury, underwent bladder neck closure and continent augmentation with formation of a catheterizable cutaneous stoma on the anterior abdominal wall, using right colon and right colon/ileum configurations. When ureteral reflux and obstruction are absent, the patient's bladder was used which spared the added risk of ureteral implantation and possible ureteral stricture while increasing total bladder capacity. In a select group of patients with intractable incontinence, perineal and penile skin breakdown, or urethral fistulae, bladder neck closure and urinary diversion by suprapubic catheter or continent augmentation has proven to be a reliable and effective alternative to an ileal conduit.     

Microbial flora in ileal and colonic neobladders

OBJECTIVE: To describe bacterial colonization in patients with ileal and colonic neobladders. METHODS: Twenty-three patients with right colon neobladders, 30 with ileal neobladders, 11 who had undergone radical prostatectomy, and 6 healthy controls were included. Culture of clean-catch, midstream urine specimens was done weekly for 3 weeks, and this was repeated after 6 months. Residual urine was measured, and the patients were interviewed about leakage. All patients and controls were antibiotic free during the study except for 13 of the ileal neobladder patients, who were treated with trimethoprim 100mg daily. RESULTS: Urine cultures from controls and prostatectomy patients were negative for bacteria, whereas 67% of the specimens from patients with neobladders, not on antibiotic therapy, were culture positive, and half of these contained uropathogenic species, such as Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterococcus faecalis. Bacterial colonization (including uropathogenic strains) was strongly correlated with residual urine (p<0.005), but not with leakage. Anaerobic strains were found more frequently (p=0.04) in urine from ileal neobladders than in urine from colonic neobladders. The 13 patients with ileal neobladders and on prophylactic antibiotic therapy carried bacteriuria in 80% of the samples, the majority being anaerobic strains. Uropathogenic strains, mainly Enterecoccus faecalis was revealed in 30% of the samples. CONCLUSIONS: The lower urinary tract of patients with ileal or colonic neobladders is heavily colonized with potentially uropathogenic and anaerobic bacteria. Complete bladder emptying reduces the bacterial burden. Anaerobic colonization is increased in neobladders reconstructed from ileum. Prophylactic antibiotic therapy does not seem to reduce the bacterial burden, but interferes with the bacterial composition.     

Effect of colonic distention on ileal motor activity with evidence of coloileal reflex

Chyme delivery from the ileum to the colon is controlled by various neurologic and hormonal factors, many of which remain to be identified. In this report we investigated the effect of colonic distention on ileal motility with the aim of identifying the mechanism of chyme delivery from the ileum to the colon. The right colon of 16 healthy volunteers (12 men and 4 women; mean age 36 ± 9 years standard deviation) was distended by a balloon that was filled with saline solution in increments of 20 ml. The pressure response of the terminal ileum to the colonic distention was recorded by a saline-perfused tube. The test was repeated in nine subjects after the colonic segment around the balloon was anesthetized by xylocaine injection into the colonic wall. Twenty and 40 ml colonic distention produced no significant ileal pressure response. Colonic distention with 60 ml produced an increase in colonic pressure (P < 0.05), as measured by intraballoon pressure, and a decrease in ileal pressure (P < 0.05); a similar response was achieved with 80 ml distention. At 100 ml colonic distention, the balloon was dispelled to the transverse colon. Distention up to 100 ml of the anesthetized colonic segment produced no significant colonic or ileal pressure response. The flow of chyme from the small to the large gut appears to be controlled by a reflex mechanism that we call the ‘coloileal reflex.’ Whenever the right colon is distended with a substantial volume of chyme that increases the intraluminal pressure, it is suggested that ileal relaxation occurs, which delays the emptying of chyme from the ileum.