Characterization of the peristaltic reflex in murine distal colon.

Ascending and descending neuromuscular reflexes play an important role in gastrointestinal motility. However, the underlying mechanisms in colon are incompletely understood. Nerve stimulation (NS)- and balloon distention (BD)-mediated reflexes in distal colonic circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) of mice were investigated using conventional intracellular recordings. In the CSM, NS evoked ascending purinergic inhibitory junction potentials (IJPs), whereas BD induced atropine-sensitive ascending depolarization with superimposed action potentials (APs). The ascending depolarization reached a peak ∼4-7 s after the onset of distention and gradually returned to baseline after termination of the distention. In the LSM, NS produced an ascending biphasic IJP followed by a train of atropine-sensitive APs. Both stimuli produced similar descending IJPs in CSM and LSM, which were blocked by MRS-2500 and MRS-2179, putative purinergic receptor blockers. These data indicate that in the murine distal colon, descending purinergic inhibition in both CSM and LSM occurs. Ascending responses are more complex, with NS producing both inhibition and excitation to CSM and LSM, and BD evoking only cholinergic excitation.

Impaired platelet-derived growth factor receptor expression and function in cultured lower esophageal sphincter circular smooth muscle cells from W/W(v) mutant mice.

We have previously demonstrated that lower esophageal sphincter (LES) circular smooth muscle (CSM) is functionally impaired in W/W(v) mutant mice that lack interstitial cells of Cajal, and speculated that this could be due to altered smooth muscle differentiation. Platelet-derived growth factor (PDGF) is involved in the maturation and differentiation of smooth muscle. To determine whether PDGF expression and (or) function is altered in W/W(v) mutant mice, PDGF-Rß expression was measured using RT-PCR, qPCR, and immunocytochemistry, and Ca(2+) imaging and perforated patch clamp recordings performed in isolated LES CSM cells. RT-PCR and immunocytochemistry showed significantly reduced PDGF-Rß expression in the LES from mutant as opposed to wild-type mice. Quantitative comparison of CSM cell numbers in histological specimens revealed a significantly increased average cell size in the mutant tissue. The specific PDGF-Rß ligand, PDGF-BB, caused a significant increase in intracellular Ca(2+) in cells from the wild-type mice compared with the mutants. Using a ramp protocol, PDGF-BB caused a 2-fold increase in outward K(+) currents in cells from the wild-type mice, whereas no significant increase was measured in the cells from the mutants. We conclude that the expression and function of PDGF-Rß in LES CSM from W/W(v) mice is impaired, providing further evidence that LES CSM is abnormal in W/W(v) mutants.

Altered Esophageal Smooth Muscle Phenotype in Achalasia.

Background/Aims: Achalasia is a disorder characterized by impairment in lower esophageal sphincter relaxation and esophageal aperistalsis, caused primarily by loss of inhibitory innervation. However, little is known about associated changes in esophageal smooth muscle. We examined the contractile phenotype and innervation of the circular smooth muscle, as well as inflammatory status, and correlated these with patient-specific parameters. Methods: Circular smooth muscle biopsies were obtained in consecutive patients with achalasia undergoing peroral endoscopic myotomy. Axonal innervation and neurotransmitter subtypes were determined with immunocytochemistry, and this was used with quantitative Polymerase Chain Reaction (qPCR) to characterize smooth muscle proliferation and cellular phenotype, as well as collagen expression. These were compared to control tissue obtained at esophagectomy and correlated with patient demographic factors including age, onset of symptoms, and Eckhardt score. Results: Biopsies of smooth muscle were obtained from 25 patients with achalasia. Overall, there was increased mast cell number and collagen deposition but increased smooth muscle cell proliferation vs control. There was a striking drop in axon density over controls, with no differences among subtypes of achalasia. Immunocytochemical analysis showed increased expression of the contractile marker α-smooth muscle actin, principally in Type 1 achalasia, that increased with disease duration, while qPCR identified increased mRNA for smoothelin with decreased myosin heavy chain and collagen 3a1, but not collagen 1a1. Conclusions: The thickened circular smooth muscle layer in achalasia is largely denervated, with an altered contractile phenotype and fibrosis. Biopsies obtained during peroral endoscopic myotomy provide a means to further study the pathophysiology of achalasia.

Canadian Digestive Health Foundation Public Impact Series 3: irritable bowel syndrome in Canada. Incidence, prevalence, and direct and indirect economic impact.

The Canadian Digestive Health Foundation initiated a scientific program to assess the incidence, prevalence, mortality and economic impact of digestive disorders across Canada in 2009. The current article presents the updated findings from the study concerning irritable bowel syndrome.

Evidence for altered circular smooth muscle cell function in lower esophageal sphincter of W/Wv mutant mice.

Nitrergic neurotransmission to gut smooth muscle is impaired in W/W(v) mutant mice, which lack intramuscular interstitial cells of Cajal (ICC-IM). In addition, these mice have been reported to have smaller amplitude unitary potentials (UPs) and a more negative resting membrane potential (RMP) than control mice. These abnormalities have been attributed to absence of ICC-IM, but it remains possible that they are due to alterations at the level of the smooth muscle itself. Amphotericin-B-perforated patch-clamp recordings and Ca(2+) imaging (fura 2) were compared between freshly isolated single circular smooth muscle cells (CSM) from W/W(v) mutant and control mice lower esophageal sphincter (LES). There was no significant difference in seal resistance, capacitance, or input resistance in response to applied electrotonic current pulses between CSM cells from W/W(v) mutants and controls. Compared with control mice, RMP was more negative and UPs significantly smaller in CSM cells from mutant mice LES. Administration of caffeine induced an inward current in cells from both mutant and control mice, but the current density was significantly larger in cells from W/W(v) mutants. Membrane potential hyperpolarization induced by sodium nitroprusside was larger in cells from control mice vs. W/W(v) mutants. In addition, intracellular Ca(2+) transients induced by caffeine were significantly increased in cells from mutants. These findings indicate that LES CSM is abnormal in W/W(v) mutant mice. Thus some physiological functions attributed to ICC-IM based on experiments in smooth muscle of ICC deficient mice may need to be reconsidered.

P2Y1 receptors mediate apamin-sensitive and -insensitive inhibitory junction potentials in murine colonic circular smooth muscle.

Purinergic inhibitory neuromuscular transmission plays an important role in the control of intestinal motility. In most tissues this neurotransmission is apamin-sensitive, but recent studies in human colonic circular smooth muscle (CSM) suggest the presence of apamin-insensitive purinergic inhibitory junction potentials (IJPs). The current studies used conventional intracellular recordings on colonic CSM strips to characterize the purinergic IJPs in murine colonic CSM. P2Y1 receptor expression was examined by using reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. The IJP induced by nerve stimulation (NS) of one and four pulses in neuronal nitric-oxide synthase knockout mice consists of an apamin-sensitive and a dominant apamin-resistant component. These are identical to the IJPs in wild-type and CD1 mice in the presence of N(omega)-nitro-l-arginine methyl ester (200 microM) and were significantly inhibited by alpha,beta-methylene ATP (50 microM), an analog of ATP. IJPs were not affected by the P2X receptor antagonist 2',3'-o-(2,4,6-trinitrophenyl)-ATP (10 microM). Furthermore, apamin-resistant IJPs induced by single-pulse NS were abolished by pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (100 microM), a P2 receptor antagonist; 2'-deoxy-N6-methyl adenosine 3,5-diphosphate (MRS-2179; 10 microM), a selective P2Y1 receptor antagonist; and tetrodotoxin (1 microM). Aboral NS induced apamin-sensitive purinergic IJPs, whereas oral and circumferential NS produced apamin-sensitive and -resistant IJPs, with the latter predominating. RT-PCR and immunohistochemistry confirmed the presence of P2Y1 receptors on smooth muscle and in the myenteric plexus. These data suggest that, depending on stimulus location, activation of P2Y1 receptors produces both apamin-sensitive and apamin-resistant IJPs in murine colonic CSM.

Screening and therapy for malnutrition and related gastro-intestinal disorders in systemic sclerosis: recommendations of a North American expert panel.

OBJECTIVES: To develop a set of recommendations for clinicians caring for patients with systemic sclerosis (SSc) to guide their approach to the patient with malnutrition and possible malabsorption. METHODS: The Canadian Scleroderma Research Group convened a meeting of experts in the areas of nutrition, speech pathology, oral health in SSc, SSc and gastroenterology to discuss the nutrition-GI paradigm in SSc. This meeting generated a set of recommendations based on expert opinion. RESULTS: Physicians should screen ALL patients with SSc for malnutrition. The physician should ask a series of questions that pertain to GI involvement. Patients who screen positive for malnutrition should be referred to a dietitian and gastroenterologist. Referral to a patient support group should be considered and if screening reveals oral health problems, referral to a dentist, preferably with expertise in treating patients with SSc, should be done. All SSc patients should weigh themselves monthly and report any sudden significant changes in weight. They should be assessed by a rheumatologist once a year for signs of malnutrition. CONCLUSIONS: Malnutrition may be common in SSc and a multidisciplinary approach is important.

Meeting the Motility Educational Requirements of the Gastroenterology Trainee in the 21st Century.

BACKGROUND: Gastrointestinal (GI) motility and functional disorders comprise over two-third of referrals to GI specialists yet training programs are disproportionately focused on endoscopy, inflammatory bowel disease and liver disease. Trainees at many centres receive minimal or no formal training in motility disorders and have little or no exposure to motility testing. Our purpose was to develop an educational intervention to address this learning need. METHODS: We designed a formal training program comprised of didactic sessions, workshops and hands-on motility sessions with live demonstrations designed to be held over the course of a weekend. Faculty for the course were experienced GI motility experts from across Canada. Resident trainees from all Canadian GI fellowship programs were invited to attend. Pre- and post-tests were administered to measure the baseline learning needs and the impact of the program. Course evaluations were completed by attendees. RESULTS: Three annual courses were offered over the past 3 years. Both adult and paediatric gastroenterology trainees attended the programs. The majority of training programs from Canada were represented. Baseline testing of attendees revealed a fundamental lack of understanding of GI motility concepts and their clinical implications. Postcourse test scores demonstrated a significant improvement in motility knowledge. Course evaluations of the content and faculty presentations received uniformly positive reviews. CONCLUSIONS: There is a pervasive lack of clinical knowledge of GI motility among Canadian GI subspecialty trainees. A focused weekend intensive course is one step in addressing this learning need.

Screening and Treatment Outcomes in Adults and Children With Type 1 Diabetes and Asymptomatic Celiac Disease: The CD-DIET Study.

OBJECTIVE: To describe celiac disease (CD) screening rates and glycemic outcomes of a gluten-free diet (GFD) in patients with type 1 diabetes who are asymptomatic for CD. RESEARCH DESIGN AND METHODS: Asymptomatic patients (8-45 years) were screened for CD. Biopsy-confirmed CD participants were randomized to GFD or gluten-containing diet (GCD) to assess changes in HbA1c and continuous glucose monitoring over 12 months. RESULTS: Adults had higher CD-seropositivity rates than children (6.8% [95% CI 4.9-8.2%, N = 1,298] vs. 4.7% [95% CI 3.4-5.9%, N = 1,089], P = 0.035) with lower rates of prior CD screening (6.9% vs. 44.2%, P < 0.0001). Fifty-one participants were randomized to a GFD (N = 27) or GCD (N = 24). No HbA1c differences were seen between the groups (+0.14%, 1.5 mmol/mol; 95% CI -0.79 to 1.08; P = 0.76), although greater postprandial glucose increases (4-h +1.5 mmol/L; 95% CI 0.4-2.7; P = 0.014) emerged with a GFD. CONCLUSIONS: CD is frequently observed in asymptomatic patients with type 1 diabetes, and clinical vigilance is warranted with initiation of a GFD.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Management of Irritable Bowel Syndrome (IBS).

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) is one of the most common gastrointestinal (GI) disorders, affecting about 10% of the general population globally. The aim of this consensus was to develop guidelines for the management of IBS. METHODS: A systematic literature search identified studies on the management of IBS. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an iterative online platform and then finalized and voted on by a multidisciplinary group of clinicians and a patient. RESULTS: Consensus was reached on 28 of 31 statements. Irritable bowel syndrome is diagnosed based on symptoms; serological testing is suggested to exclude celiac disease, but routine testing for C-reactive protein (CRP), fecal calprotectin or food allergies is not recommended. A trial of a low fermentable oligosaccharides, disaccharides, monosaccharides, polyols (FODMAP) diet is suggested, while a gluten-free diet is not. Psyllium, but not wheat bran, supplementation may help reduce symptoms. Alternative therapies such as peppermint oil and probiotics are suggested, while herbal therapies and acupuncture are not. Cognitive behavioural therapy and hypnotherapy are suggested psychological therapies. Among the suggested or recommended pharmacological therapies are antispasmodics, certain antidepressants, eluxadoline, lubiprostone, and linaclotide. Loperamide, cholestyramine and osmotic laxatives are not recommended for overall IBS symptoms. The nature of the IBS symptoms (diarrhea-predominant or constipation-predominant) should be considered in the choice of pharmacological treatments. CONCLUSIONS: Patients with IBS may benefit from a multipronged, individualized approach to treatment, including dietary modifications, psychological and pharmacological therapies.

Patient Engagement and Multidisciplinary Involvement Has an Impact on Clinical Guideline Development and Decisions: A Comparison of Two Irritable Bowel Syndrome Guidelines Using the Same Data.

BACKGROUND AND AIM: The value of a multidisciplinary group and patient engagement in guideline groups is uncertain. We compared the recommendations of two guidelines that used the same data during the same time frame but with different participants to obtain a "real world" perspective on influence of the composition of guideline groups. METHODS: The Canadian Association of Gastroenterology (CAG) and the American College of Gastroenterology (ACG) recently updated their clinical practice guidelines for the management of Irritable Bowel Syndrome (IBS). Both the CAG and ACG used the same methodology and methodologist and were presented with the same data for interpretation. The ACG group consisted of predominantly academic gastroenterologists, while the CAG group also included general practitioners, a psychiatrist, a psychologist and a patient representative. The CAG group were also asked what components of the group were valuable. RESULTS: There were 14 statements with the same or similar recommendations. There were 10 statements in the CAG guideline not addressed by the ACG guideline and five recommendations where the opposite was the case. There was one statement that the two groups both addressed, but each group came to different conclusions. CAG members were in 100% agreement that involving a patient and having a multidisciplinary team was valuable and may have played a role in these differing interpretations of the same data in an IBS guideline. CONCLUSIONS: There has been little uptake of patient involvement and multidisciplinary teams in guideline groups. However, this study provides a unique example of added benefit through broader group representation.

Wait time for endoscopic evaluation at a Canadian tertiary care centre: comparison with Canadian Association of Gastroenterology targets.

BACKGROUND: In recent years, there has been considerable concern regarding wait times for Canadian health care, which led the Canadian Association of Gastroenterology (CAG) to develop specific wait time targets. OBJECTIVES: To quantify wait times for endoscopic procedures at a tertiary care centre and correlate these with clinical presentation, impact on quality of life (QOL) and final diagnosis; and to determine how well the CAG wait time targets are being met. METHODS: Patients completed a 12-item questionnaire regarding wait times and their impact on QOL. A blind review was performed of the endoscopic results, with a specific focus on correlating wait time with a final diagnosis of serious and treatable diseases. RESULTS: The average total wait time for the 417 participants in the present study was 229 days; 78.6% did not meet CAG wait time targets. The wait time for screening colonoscopy was longer, and the proportion of patients meeting wait time targets was significantly smaller, than for patients referred with iron deficiency anemia or a positive fecal occult blood test result. The 41 patients deemed to have a high-impact diagnosis established by endoscopy had a median wait time of 115 days, and only 23.5% met wait time targets. Overall, 38.4% of patients believed that their wait was too long, 13.9% missed school or work in the preceding month because of gastrointestinal symptoms and 23% reported being very worried about having a serious disease. CONCLUSIONS: The majority of patients waiting for endoscopy did not meet CAG wait time targets, with the screening colonoscopy group faring the worst. Many of these patients await a definitive diagnosis of serious diseases that negatively impact QOL.

Comparison of Flexible Sigmoidoscopy Screening in Average Risk Patients Performed by Nurses Versus Gastroenterologists.

BACKGROUND: Screening sigmoidoscopy is effective in reducing mortality from colorectal cancer. In 2009, Cancer Care Ontario (CCO) launched a nurse-performed screening flexible sigmoidoscopy program at Hotel Dieu Hospital, Kingston, Ontario. Prior to this program, there was a pilot sigmoidoscopy screening program by gastroenterologists in a similar average risk cohort. AIM: To compare neoplasia detection rates and associated costs of screening sigmoidoscopy performed by nurses and gastroenterologists. METHOD: A retrospective chart review was conducted on flexible sigmoidoscopies performed as part of two average risk screening programs performed by gastroenterologists and nurse-endoscopists. Detected polyps were categorized as hyperplastic, low-risk adenomas or high-risk adenomas. Average cost per procedure was estimated based on physician fee for service charges, nurse wage and benefits, physician supervisory fees, pathology costs and administrative expenses. RESULTS: There were 538 procedures performed by nurses and 174 by physicians. Adenomas were detected in 18% of nurse-performed procedures versus 9% in physician-performed procedures (p=0.003), with the higher adenoma detection rate restricted to low risk adenomas. One cancer was found in the physician group. Seven physicians performed the 174 sigmoidoscopies, with one physician performing the majority. This physician's adenoma detection rate was 4.5%, whereas detection rate for the remaining physicians combined was 16.5%. Nurses biopsied more polyps per case (0.96 versus 0.18). Average estimated cost per case was greater for nurses ($387.54 versus $309.37). CONCLUSION: Well-trained nurse-endoscopists can provide an effective service for colorectal cancer screening, but as currently structured in Ontario, the associated cost is higher for nurse-performed procedures.

Two-year retrospective analysis of patients undergoing direct to procedure flexible sigmoidoscopy investigation with rectal bleeding as a primary complaint.

BACKGROUND AND AIMS: Rectal bleeding affects ~15 % of the general population and is a common reason for referral to gastroenterologists by primary care physicians. Direct to procedure flexible sigmoidoscopy is an appealing modality to investigate rectal bleeding due its diagnostic yield, safety profile, and accessibility. Patients referred on a routine basis for direct to procedure clinic by primary care physicians with the sole complaint of rectal bleeding have not previously been studied. Our study aims to explore the spectrum of diagnoses and evaluate for potential clinical predictors of underlying pathology in this specific patient population. METHODS: In total, 528 charts of patients referred to the Kingston General Hospital and Hotel Dieu Hospital endoscopy units (Kingston, Canada) with the sole complaint of rectal bleeding were reviewed. All of these patients were referred on a routine basis to direct to procedure clinic from primary care physicians. The performance of various clinical variables in predicting significant pathology was assessed by univariate analysis. RESULTS: The diagnostic spectrum of the cohort studied included hemorrhoids (75.5 %), anal fissures (4 %), ulcerative colitis (3.2 %), Crohn's disease (1.1 %), indeterminate proctitis/colitis (1.7 %), and colorectal malignancy (2.7 %). Of the various clinical variables assessed, only male sex predicted significant pathology (25.2 % of males vs 17.6 % of females, P  < 0.05). CONCLUSION: Our study highlights the need for a thorough investigation of rectal bleeding given the lack of clinical predictors. Future prospective studies with more patients are needed to fully assess the utility of various clinical variables in predicting pathology in this patient population. This would allow for more effective triaging of a routine rectal bleeding, a very common reason for patient referral to gastroenterologists by primary care physicians. Flexible sigmoidoscopy was not associated with complications or missed diagnosis in our study. As such, the technique appears to be a suitable initial investigative modality for patients with rectal bleeding.

Canadian consensus on medically acceptable wait times for digestive health care.

BACKGROUND: Delays in access to health care in Canada have been reported, but standardized systems to manage and monitor wait lists and wait times, and benchmarks for appropriate wait times, are lacking. The objective of the present consensus was to develop evidence- and expertise-based recommendations for medically appropriate maximal wait times for consultation and procedures by a digestive disease specialist. METHODS: A steering committee drafted statements defining maximal wait times for specialist consultation and procedures based on the most common reasons for referral of adult patients to a digestive disease specialist. Statements were circulated in advance to a multidisciplinary group of 25 participants for comments and voting. At the consensus meeting, relevant data and the results of voting were presented and discussed; these formed the basis of the final wording and voting of statements. RESULTS: Twenty-four statements were produced regarding maximal medically appropriate wait times for specialist consultation and procedures based on presenting signs and symptoms of referred patients. Statements covered the areas of gastrointestinal bleeding; cancer confirmation and screening and surveillance of colon cancer and colonic polyps; liver, biliary and pancreatic disorders; dysphagia and dyspepsia; abdominal pain and bowel dysfunction; and suspected inflammatory bowel disease. Maximal wait times could be stratified into four possible acuity categories of 24 h, two weeks, two months and six months. FUTURE DIRECTIONS: Comparison of these benchmarks with actual wait times will identify limitations in access to digestive heath care in Canada. These recommendations should be considered targets for future health care improvements and are not clinical practice guidelines.

A Patient Flow Analysis: Identification of Process Inefficiencies and Workflow Metrics at an Ambulatory Endoscopy Unit.

Background. The increasing demand for endoscopic procedures coincides with the paradigm shift in health care delivery that emphasizes efficient use of existing resources. However, there is limited literature on the range of endoscopy unit efficiencies. Methods. A time and motion analysis of patient flow through the Hotel-Dieu Hospital (Kingston, Ontario) endoscopy unit was followed by qualitative interviews. Procedures were directly observed in three segments: individual endoscopy room use, preprocedure/recovery room, and overall endoscopy unit utilization. Results. Data were collected for 137 procedures in the endoscopy room, 139 procedures in the preprocedure room, and 143 procedures for overall room utilization. The mean duration spent in the endoscopy room was 31.47 min for an esophagogastroduodenoscopy, 52.93 min for a colonoscopy, 30.47 min for a flexible sigmoidoscopy, and 66.88 min for a double procedure. The procedure itself accounted for 8.11 min, 34.24 min, 9.02 min, and 39.13 min for the above procedures, respectively. The focused interviews identified the scheduling template as a major area of operational inefficiency. Conclusions. Despite reasonable procedure times for all except colonoscopies, the endoscopy room durations exceed the allocated times, reflecting the impact of non-procedure-related factors and the need for a revised scheduling template. Endoscopy units have unique operational characteristics and identification of process inefficiencies can lead to targeted quality improvement initiatives.

Canadian Consensus Conference on the management of gastroesophageal reflux disease in adults - update 2004.

BACKGROUND: Gastroesophageal reflux disease (GERD) is the most prevalent acid-related disorder in Canada and is associated with significant impairment of health-related quality of life. Since the last Canadian Consensus Conference in 1996, GERD management has evolved substantially. OBJECTIVE: To develop up-to-date evidence-based recommendations relevant to the needs of Canadian health care providers for the management of the esophageal manifestations of GERD. CONSENSUS PROCESS: A multidisciplinary group of 23 voting participants developed recommendation statements using a Delphi approach; after presentation of relevant data at the meeting, the quality of the evidence, strength of recommendation and level of consensus were graded by participants according to accepted principles. OUTCOMES: GERD applies to individuals who reflux gastric contents into the esophagus causing symptoms sufficient to reduce quality of life, injury or both; endoscopy-negative reflux disease applies to individuals who have GERD and a normal endoscopy. Uninvestigated heartburn-dominant dyspepsia - characterised by heartburn or acid regurgitation - includes erosive esophagitis or endoscopy-negative reflux disease, and may be treated empirically as GERD without further investigation provided there are no alarm features. Lifestyle modifications are ineffective for frequent or severe GERD symptoms; over-the-counter antacids or histamine H2-receptor antagonists are effective for some patients with mild or infrequent GERD symptoms. Proton pump inhibitors are more effective for healing and symptom relief than histamine H2-receptor antagonists; their efficacy is proportional to their ability to reduce intragastric acidity. Response to initial therapy - a once-daily proton pump inhibitor unless symptoms are mild and infrequent (fewer than three times per week) - should be assessed at four to eight weeks. Maintenance medical therapy should be at the lowest dose and frequency necessary to maintain symptom relief; antireflux surgery is an alternative for a small proportion of selected patients. Routine testing for Helicobacter pylori infection is unnecessary before starting GERD therapy. GERD is associated with Barrett's epithelium and esophageal adenocarcinoma but the risk of malignancy is very low. Endoscopic screening for Barrett's epithelium may be considered in adults with GERD symptoms for more than 10 years; Barrett's epithelium and low-grade dysplasia generally warrant surveillance; endoscopic or surgical management should be considered for confirmed high-grade dysplasia or malignancy. CONCLUSION: Prospective studies are needed to investigate clinically relevant risk factors for the development of GERD and its complications; GERD progression, on and off therapy; optimal management strategies for typical GERD symptoms in primary care patients; and optimal management strategies for atypical GERD symptoms, Barrett's epithelium and esophageal adenocarcinoma.

Role of sarcoplasmic reticulum in control of membrane potential and nitrergic response in opossum lower esophageal sphincter.

1. We previously demonstrated that a balance of Ca2+-activated Cl- current (ICl(Ca)) and K+ current activity sets the resting membrane potential of opossum lower esophageal sphincter (LES) circular smooth muscle at approximately -41 mV, which leads to continuous spike-like action potentials and the generation of basal tone. Ionic mechanisms underlying this basal ICl(Ca) activity and its nitrergic regulation remain unclear. Recent studies suggest that spontaneous Ca2+ release from sarcoplasmic reticulum (SR) and myosin light chain kinase (MLCK) play important roles. The current study investigated this possibility. Conventional intracellular recordings were performed on circular smooth muscle of opossum LES. Nerve responses were evoked by electrical square wave pulses of 0.5 ms duration at 20 Hz. 2. In the presence of nifedipine (1 microm), substance P (1 microm), atropine (3 microm) and guanethidine (3 microm), intracellular recordings demonstrated a resting membrane potential (MP) of -38.1+/-0.7 mV (n=25) with spontaneous membrane potential fluctuations (MPfs) of 1-3 mV. Four pulses of nerve stimulation induced slow inhibitory junction potentials (sIJPs) with an amplitude of 6.1+/-0.3 mV and a half-amplitude duration of 1926+/-147 ms (n=25). 3. 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a specific guanylyl cyclase inhibitor, abolished sIJPs, but had no effects on MPfs. Caffeine, a ryanodine receptor agonist, hyperpolarized MP and abolished sIJPs and MPfs. Ryanodine (20 microm) inhibited the sIJP and induced biphasic effects on MP, an initial small hyperpolarization followed by a large depolarization. sIJPs and MPfs were also inhibited by cyclopiazonic acid, an SR Ca2+ ATPase inhibitor. Specific ICl(Ca) and MLCK inhibitors hyperpolarized the MP and inhibited MPfs and sIJPs. 4. These data suggest that (1). spontaneous release of Ca2+ from the SR activates ICl(Ca), which in turn contributes to resting membrane potential; (2). MLCK is involved in activation of ICl(Ca); (3). inhibition of ICl(Ca) is likely to underlie sIJPs induced by nitrergic innervation.

Relationship between the number of positive fecal occult blood tests and the diagnostic yield of colonoscopy.

BACKGROUND: In 2007, Ontario launched a colon cancer screening program for average-risk individuals based on biennial fecal occult blood tests (FOBTs) on three fecal samples, followed by colonoscopy for individuals who tested positive. OBJECTIVE: To determine whether >1 positive screening FOBT was predictive of finding advanced neoplasia at colonoscopy. METHODS: A retrospective chart review of outpatient colonoscopic procedures performed at Hotel Dieu Hospital (Kingston, Ontario) in the first two years of the colon cancer screening program was conducted, focusing on endoscopic and pathological findings. RESULTS: Of 5556 individuals undergoing colonoscopy, 346 were referred for positive FOBT. Overall, 41 (11.8%) patients with a positive FOBT had colon cancer. In 16 (4.6%) cases, the number of positive FOBTs was not reported. For the 330 individuals in whom the number of positive tests was specified, 198, 71 and 61 cases had one, two and three positive results, respectively. Cancer was found at colonoscopy in 11 (5.6%), 11 (15.5%) and 18 (29.5%) of individuals with one, two and three positive FOBT results, respectively (OR 3.0 [95% CI 1.2 to 7.3] and 6.5 [95% CI 2.8 to 15.0] for two or three positive FOBTs compared with one; P=0.015 and P<0.001, respectively). High-risk adenomas (>1 cm in diameter, villous component and/or high-grade dysplasia) were found in 41 (20.8%), 29 (42.0%) and 25 (41.0%) individuals with one, two and three positive FOBTs, respectively (OR 2.8 [95% CI 1.5 to 5.0] and 2.4 [95% CI 1.3 to 4.5] for two or three positive FOBTs compared with one; P=0.001 and P=0.006, respectively). CONCLUSIONS: The diagnostic yield of colonoscopy varied directly with the number of positive FOBTs. This information may be useful in assigning scheduling priority for patients with positive FOBTs.