Pharmacological modulation of gut mucosal and large vessel blood flow.

BACKGROUND: Constipation, diminished gut blood flow, ischaemic colitis and drug therapy may be associated. AIM: To study the effect of constipating medication on, and the regulation of, gut blood flow. METHODS: 24 healthy females (mean age 30) received, in a double-blind, three-way crossover study: (i) placebo, (ii) ipratropium 40 microg by inhalation (positive control known to reduce rectal mucosal blood flow) and (iii) oral loperamide 4 mg. Mucosal blood flow was measured at the splenic flexure and rectum using laser Doppler flowmetry. Blood flow in the superior and inferior mesenteric arteries was measured by trans-abdominal Doppler ultrasound. RESULTS: Ipratropium decreased rectal mucosal blood flow by 16% (P=0.009) and splenic flexure mucosal blood flow by 8% (P=0.075). Loperamide caused no change in rectal (P=0.40) or splenic flexure mucosal blood flow (P=0.73). Neither treatment changed superior or inferior mesenteric artery blood flow. Splenic flexure mucosal blood flow showed a positive correlation with rectal mucosal blood flow (r=0.69; P<0.0001). CONCLUSIONS: Vasoactive agents may reduce gut mucosal blood flow in the absence of reduced large vessel flow. Constipating drugs do not necessarily reduce gut blood flow. Rectal mucosal blood flow correlates with splenic flexure mucosal flow, and potentially may be used as a more convenient surrogate for studying splenic flexure blood flow.

Review article: Population screening for colorectal cancer.

Colorectal cancer is a common cancer and common cause of death. The mortality rate from colorectal cancer can be reduced by identification and removal of cancer precursors, adenomas, or by detection of cancer at an earlier stage. Pilot screening programmes have demonstrated decreased colorectal cancer mortality; as a result many countries are developing colorectal cancer screening programmes. The most common modalities being evaluated are faecal occult blood testing, flexible sigmoidoscopy and colonoscopy. Implementation of screening tests has been hampered by cost, invasiveness, availability of resources and patient acceptance. New technologies such at computed tomographic colonography and stool screening for molecular markers of neoplasia are in development as potential minimally invasive tools. This review considers who should be screened, which test to use and how often to screen.

Recent developments in CT colonography.

CT colonography allows reliable, non-invasive, rapid, high resolution imaging of the whole large bowel. Recent advances in technology such as computer-aided detection (CAD), scanning with or without bowel preparation, and low radiation are continually developing to improve the efficacy of this technique. This review will update the reader as to ongoing developments while presenting current thinking from the gastroenterological perspective.

Percutaneous endoscopic gastrostomy: a review of indications, complications and outcome.

Percutaneous endoscopic gastrostomy (PEG) was first described in 1980 as an effective method of feeding via the stomach in situations where oral intake is not possible. Its simplicity has led to its potential use in areas of dubious clinical benefit. Our unit has faced a major increase in referrals for PEG insertion over the last 2 years. For this reason we decided to audit our PEG insertion procedures with regard to indications, complications, outcome and follow up. We studied 168 patients who had an initial PEG insertion during the period 1 February 1996-31 January 1998. The medical records of these patients were reviewed with regard to the procedure, antibiotic use and complications. All patients (or carers or next of kin) were contacted by telephone to provide details regarding late complications and follow up. There were 87 females and 81 males (aged 16-98 years, median age 70 years). At 2 years, 67% were alive. The most frequent indication for PEG insertion was a neurological condition, the commonest being stroke. Most patients received either ticarcillin/clavulanic acid or cephazolin antibiotic prophylaxis before and after the procedure. In six patients (3.6%) infection at the PEG site required intravenous antibiotics. Four of these six patients did not have antibiotic prophylaxis. Only two deaths could be directly related to the procedure. Three died within 7 days of the procedure due to unrelated medical complications. Sixteen patients died within 1 month, the majority of these patients did not leave hospital. One-fifth of the patients (35/168) had their PEG removed due to the re-establishment of oral feeding, with median time of use, 4.3 months. It is a safe, effective feeding method in the elderly, but experience with case selection, the procedure and careful follow up remain essential. The use of prophylactic antibiotics resulted in few significant infections of the PEG site. Up to one-fifth of patients will require their PEG only for a short term.

Distribution of colorectal adenomas: implications for bowel cancer screening.

OBJECTIVE: To determine the distribution of colorectal adenomas relative to the splenic flexure in an asymptomatic population undergoing colonoscopy, as an indicator of the number of patients with adenomas who would be missed by screening with flexible sigmoidoscopy. DESIGN: Retrospective survey of medical records. SETTING: Private endoscopy centres in Melbourne, Victoria. SUBJECTS: All 1131 asymptomatic individuals who underwent full colonoscopy between 1 January 1995 and 31 December 1997 after referral from a bowel cancer prevention program organised by the endoscopy centres. People referred were aged either 40 years or over with a first-degree relative with bowel cancer, or 50 years or over with marked anxiety about bowel cancer. MAIN OUTCOME MEASURES: Presence and distribution of colorectal adenomas. RESULTS: Polyps were found in 270 individuals (24%) and were confirmed to be adenomas in 138 (12%). These 138 comprised 106 men and 32 women, with mean age 54 years (range, 40-78 years). Most (86%) had a single adenoma. Position of adenomas in relation to the splenic flexure was: distal only in 85 of the 138 people (62%), proximal only in 34 (25%), and both distal and proximal in 19 (14%). CONCLUSIONS: In 25% of asymptomatic people found to have adenomas by this bowel cancer prevention program, the adenomas were found only in the proximal colon, well beyond the reach of the flexible sigmoidoscope. This distribution of adenomas suggests that screening programs cannot rely solely on flexible sigmoidoscopy.

Lansoprazole quadruple therapy is effective in curing Helicobacter pylori infection.

BACKGROUND: Quadruple therapy using omeprazole combined with classic bismuth triple therapy has been advocated as optimal therapy for the cure of Helicobacter pylori (H. pylori) infection. We investigated the efficacy of substituting lansoprazole for omeprazole in proton pump quadruple therapy. MATERIALS AND METHODS: In a prospective open study, 219 consecutive patients, with either peptic ulcer disease or biopsy-proven H. pylori-associated gastritis, received seven days of lansoprazole, bismuth, tetracycline and metronidazole after three days of lansoprazole pretreatment. Cure of infection was judged by 14C urea breath test at six weeks after completion of therapy. RESULTS: On an intention to treat basis, 198 of the 219 patients (90%) were confirmed to be cured of H. pylori infection. Compliance was excellent and minimal side effects reported. CONCLUSION: Lansoprazole-based quadruple therapy achieves a very high cure rate in an unselected population of either peptic ulcer patients or those with H. pylori-associated gastritis. Recommended regimens should achieve at least 90% cure of infection. Lansoprazole quadruple therapy is effective and compares favorably with other H. pylori treatment regimens.