The mechanisms controlling the sphincter of Oddi (SO) have received considerable attention over the past two decades. Progress towards their elucidation has been slow, perhaps because of the sphincter's relative inaccessibility and the different responses of the human "resistor" as compared to the "pumper" observed in several animal models. The list of agents affecting the sphincter grows alarmingly. In this review, divided into two parts, substances have been classified as neurotransmitters, hormones, local factors and pharmacological agents. The first part considers the roles of neurotransmitters. These include (a) vasoactive intestinal polypeptide (VIP) and nitric oxide (NO). Both cause relaxation. A recent model of their complex interrelationships in smooth muscle is described. (b) Substance P (SP) and enkephalins. These produce contractions. The former can act directly. An indirect effect via cholinergic neurones may be the result of SP release from vagal afferents. (c) Catecholamines, which cause contraction or relaxation via activation of α- or β-adrenoreceptors, respectively. In the second part attention is focussed on cholecystokinin (CCK) which normally relaxes the SO via neuronal mechanisms. A CCK-sensitive pathway from sensory duodenal neurones to SO ganglia has been described. Reactive oxygen species are among the local factors discussed. Their description as being "the good, the bad and the ugly" seems merited. Pharmacological agents include NO donors, octreotide and botulinum toxin (BTX). Octreotide induces tachyoddia and may impair biliary flow. BTX has exciting potential in the diagnosis of SO abnormalities and as a therapeutic alternative to sphincterotomy. In both parts of the review current concepts of different aspects of smooth muscle control are presented. In several instances data regarding the SO is lacking. We discuss (a) the role of interstitial cell of Cajal in the control of slow waves, (b) different pathways contributing to tonic and phasic contractions, (c) the 4 levels of neural control, (d) interrelationships of immune and nervous systems, and (e) links between emotional states and gut functions.

Introduction: Inflammatory bowel disease and Familial Adenomatous Polyposis (FAP) are relatively uncommon in Gulf Arabs. Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is a surgical method for treating patients with mucosal ulcerative colitis (MUC) and FAP. This paper documents a small experience with this operation in Saudi Arabia. Methods: The charts of all patients who had either MUC or FAP and in whom an IPAA had been performed were identified and were examined in order to determine patient demographics, timing and staging of operation, operative and long term morbidity and mortality and pouch function. Results: Thirty patients underwent IPAA. There were 16 males. 29 pouches were J-pouches. 1 patient was lost to follow up. Surgery was performed for fulminating MUC in 9 patients, failed medical treatment in 12, FAP in 7 and megacolon in 2. An emergency-three stage IPAA was performed in 10 patients. 3 patients received perioperative TPN. 17 were on steroid medication. 12 developed transient anastomotic stricture. 8 developed small bowel obstruction during follow up but none needed further surgery. 1 patient developed 'pouchitis'. Two pouches were removed. The mean daily and nocturnal bowel frequency was 6 and 2 motions per day. 6 patients suffered nocturnal leakage. Conclusion: The operation of restorative proctocolectomy can be performed safely, for the few patients who needed the operation in Saudi Arabia.

Background: Gastrointestinal (GI) smooth muscle tumors are a group of intramural GI tumors formerly known as leiomyoma and leiomyosarcoma. This retrospective study was made to review our experience in surgical management of GI smooth muscle tumors. Methods: The clinical records for patients with GI smooth muscle tumors during 1993-1999 were reviewed. Results: Ten tumors were located in stomach. Abdominal pain was the main presenting symptom followed by GI bleeding. The preoperative diagnosis was made by enhanced computerized tomography (CT) on eleven patients out of thirteen, while upper GI endoscopy with biopsy identified six tumors out of thirteen patients had the test. Tumors were treated by conservative excision in four and radical excision in fourteen. Histology was leiomyoma in six patients (with mitotic figures <4 per 10 high power field) and leiomyosarcoma was found in twelve patients (with mitotic figures >4 per 10 high power field). Median follow-up was 4 years. There was one recurrence for leiomyoma (size: 6cm). All patients with leiomyosarcoma presented later with metastasis and died. Conclusion: Size and mitotic activity of tumors are the main determinant factors. Enhanced CT remains the proper diagnostic tool.

Schistosomiasis is a world wide human infection. In Saudi Arabia there are multiple endemic foci. Various methods have been used to diagnose Schistosoma mansoni. We studied 1410 patients coming from S. mansoni endemic areas with detectable antibodies by indirect hemagglutination (IHA). Stool specimens were tested for S. mansoni ova by direct smear and formol-ether concentration (FEC) methods. The objective of the study was to identify patients with active schistosomiasis using FEC method and a single direct smear. Twenty percent of IHA positive patients had active infection detected by FEC, while a single direct stool smear diagnosed only 2.4% (P<0.0001). The percentage of positive FEC was significantly increasing in linear trend with IHA level. This trend wasn't observed with direct smear examination. The current data suggest that FEC is helpful to diagnose active schistosomiasis, therefore it is recommended in IRA positive individuals.