No abstract

Intrinsic neurons containing serotonin (5-HT) are involved in the regulation of gastrointestinal motor function and are also thought to be important in the modulation of visceral sensory function. We have evaluated the effect of a specific 5-HT3 antagonist (ondansetron, O) on visceral sensation and rectal compliance in a randomized, double-blind, cross-over, placebo (P) controlled study of·16 mg 3 times/day, in healthy volunteers and patients with irritable bowel syndrome (IBS). Symptoms were also evaluated in the latter group. A 2-week run-in period was followed by two 2-week treatment arms of P and O, separated by a 2-week wash-out period. Twelve healthy subjects and 9 patients with IBS were recruited. Assessment was by daily symptom and bowel function diary, and physiological tests of anal manometry, rectal sensory testing to distension and electrical stimulation, and rectal compliance. Ten healthy subjects completed the entire study, and 6 IBS patients completed the diary card evaluation, including 5 who also completed the physiological evaluation.·caused significantly (p < 0.01) firmer stools when considering both subject groups together. In the healthy subjects no physiological parameters were altered by O. In IBS patients the rectal sensory threshold to electrical stimulation tended to increase with·(20 vs. 28 mA, P vs. O, median, p = 0.06) while the urge (80 vs. 60 ml, p = 0.05) and maximum tolerated volumes (130 vs. 90, p = 0.03) to distension tended to decrease with O. Patients with IBS experienced significantly fewer daily episodes of pain while on·(2 vs. 1, p = 0.03). Serotonin-3 antagonism (O) causes firmer bowel actions in all subjects, and may affect gut sensitivity and pain in patients with IBS.

The surgical options for treating the large bowel component of familial adenomatous polyposis are total proctocolectomy, colectomy with ileorectal anastomosis, and restorative proctocolectomy, with or without mucosectomy. Although the first of these eradicates all mucosa at risk, it carries several disadvantages, not least of which is a permanent ileostomy. There is little to choose functionally between the other two operations. The choice should be based on the perceived risk of cancer developing in any residual rectum; the factors influencing this risk are discussed.

Careful postoperative monitoring is expensive yet effective when one considers that one-quarter of the detected recurrences were suitable for potentially curative second surgery; however, only 3.6% of the original group were effectively cured. Follow-up programs should be tailored according to the stage and site of the primary to reduce costs.