Best practice & research. Clinical gastroenterology
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Best Pract Res Clin Gastroenterol · Aug 2011
ReviewCalcium, vitamin D and colorectal cancer chemoprevention.
Identifying modifiable risk factors, particularly dietary factors, which have been hypothesized to play an important role in colorectal carcinogenesis, remains crucial in developing primary prevention strategies. Calcium and vitamin D have been shown consistently in experimental studies to have anti-cancerous properties including but not limited to stimulating differentiation, reducing proliferation, and inducing apoptosis. ⋯ Intake of calcium of not more than 1000 mg/d and intake of vitamin D of 1000-2000 IU/d, achieving a level of at least 30 ng/mL, appear important for colorectal cancer prevention. More study is warranted to determine the optimal intake levels and duration to reduce the colorectal cancer risk.
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Barrett's oesophagus normally affects the distal oesophagus when metaplastic columnar lined epithelium replaces stratified squamous epithelium which predisposes to cancer development. This develops as a consequence of chronic gastroesophageal reflux (GORD). Those with Barrett's have a 40 fold increased risk of oesophageal adenocarcinoma [1]. ⋯ The main chemopreventative agents that show promise are aspirin and proton pump inhibitors (PPIs). There are other agents such as green tea, berries and antioxidants and diet that have been suggested; we discuss the evidence available for these strategies. We hope for continued improvement in the clinical trial infrastructure to facilitate testing of new pharmacological and endoscopic interventions for Barrett's oesophagus.
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Dyssynergic defecation is common and affects up to one half of patients with chronic constipation. This acquired behavioural problem is due to the inability to coordinate the abdominal and pelvic floor muscles to evacuate stools. Today, it is possible to diagnose this problem and treat this effectively with biofeedback therapy, history, prospective stool diaries, and anorectal physiological tests. ⋯ Also the symptom improvement is due a change in the underlying pathophysiology. Development of user friendly approaches to biofeedback therapy and use of home biofeedback programs will significantly enhance the adoption of this treatment by gastroenterologists and colorectal surgeons in the future. Improved reimbursement for this proven and relatively inexpensive treatment will carry a significant impact on the problem.
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Best Pract Res Clin Gastroenterol · Feb 2011
ReviewCurrent and future therapies for chronic constipation.
In this article, traditional and novel therapies for chronic constipation are reviewed. Traditional laxatives are effective at inducing bowel movements, but efficacy in long-term management and efficacy on constipation-associated abdominal symptoms are less well established, with the exception of polyethylene glycol, for which long-term studies confirm sustained efficacy. ⋯ Methylnaltrexone, a subcutaneously administered peripherally acting mu opioid receptor antagonist, has recently been approved for opioid-induced constipation in terminally ill patients. New agents under evaluation include the 5-HT4 agonists velusetrag and naronapride, the guanylate cyclase-C receptor agonist linaclotide and the peripherally acting mu opioid receptor antagonist alvimopan.