Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022104 (irritable bowel syndrome)
 8,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Motor abnormalities of the small bowel that occur only during the waking state have been reported in the irritable bowel syndrome (IBS), suggesting that central nervous system arousal is a necessary condition for expression of the disorder and that it may reflect inappropriate brain-gut interaction. This possible relationship was explored further by synchronous polysomnography and recording of upper small bowel motility in six healthy subjects and six patients with IBS. During sleep, there was no difference in the patterns of intestinal motility between the two groups. There was no difference between the rapid eye movement (REM) latency or number of REM episodes, but the proportion of REM sleep was markedly increased (36.5% +/- 5.7% vs. 18.2% +/- 5.7%; P less than 0.01) in the IBS group, although the duration of sleep was similar (468 +/- 13 minutes in IBS vs. 444 +/- 10 minutes in controls; P greater than 0.1). Sleep apnea was detected in three of six patients with IBS but was not seen in controls. The data are consistent with the model of IBS as a disorder of brain-gut interaction.
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PMID:Abnormal REM sleep in the irritable bowel syndrome. 161 20

There is a growing body of experimental data to suggest that the chronically inflamed intestine and/or colon may be subjected to considerable oxidative stress. The most probable sources of these oxidants are the phagocytic leukocytes since these cells are known to be present in large numbers in the inflamed mucosa and are known to produce significant amounts of reactive oxygen species in response to certain inflammatory stimuli. Because the colonic mucosa contains relatively small amounts of antioxidant enzymes (e.g. SOD, catalase, GSH peroxidase) it is possible that the gut mucosa may be overwhelmed during times of active inflammation which could result in intestinal injury. If reactive oxygen species play an important role in mediating mucosal injury in IBD then it should be possible to attenuate this injury by the use of antioxidants. One such drug is the sulfasalazine metabolite 5-ASA. It may not be coincidence that this potent antiinflammatory metabolite is a potent antioxidant that possesses multiple mechanisms of action including nitrogen, carbon and oxygen-centered free radical scavenging properties as well as the ability to decompose HOCl and scavenge hemoprotein-associated oxidants. In addition 5-ASA has the additional property of being able to chelate iron and render it poorly redox active. The reason that 5-ASA is so effective in vivo may be due to this multitude of antioxidant properties. This would also suggest that other, more potent antioxidants may prove beneficial in the treatment of IBD.
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PMID:Role of neutrophil-derived oxidants in the pathogenesis of intestinal inflammation. 166 88

The enteric nervous system (ENS) can be thought of as the third component of the autonomic nervous system. It is a vast network of neurons widely dispersed throughout the gut. The ENS is a dominant regulator of gut function through the action of peptide and non-peptide neurotransmitters. The most intensively studied roles of the ENS have been the regulation of secretory processes, such as gastric acid secretion, and motility. It is clear, however, that the ENS plays a broader role in the regulation of other gut functions, including mucosal defense, the gut immune response, and sphincter function. Alterations in the regulation of gut function by the ENS are likely or suspected in a number of conditions, including achalasia, Hirschsprung's disease, inflammatory bowel disease, Chagas' disease, chronic intestinal pseudoobstruction, biliary dyskinesia, tachygastria, and irritable bowel syndrome. Improved knowledge of the pathophysiology of these troublesome conditions makes effective therapy more likely in the future.
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PMID:Neuroendocrine design of the gut. 167 22

Somatostatin and octreotide have a definitive role in the management of symptomatic gut neuroendocrine tumours, particularly VIPomas and carcinoid. They probably also have a role in variceal bleeding, but this needs further confirmatory randomized trials. At present there is a potential role in the management of short bowel syndrome, dumping syndrome and gastrointestinal fistulae, but randomized clinical studies are needed. Possibly there is a role in AIDS-related diarrhoea and 'idiopathic' secretory diarrhoea, but more evidence is required. They have no role in acute pancreatitis and peptic ulcer bleeding. Irritable bowel syndrome remains unexplored but unlikely to benefit.
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PMID:Somatostatin and octreotide in gastroenterology. 168 74

Pronounced changes in gut neuropeptide content and innervation patterns have been observed in the inflamed intestine of patients with inflammatory bowel disease. It is not known to date whether these changes in neuropeptides are due to altered synthesis and release from intrinsic and/or extrinsic neurons and nerve fibers. The changes in circular smooth muscle response associated with diminished VIP in the intestine of patients with Crohn's disease suggests that VIP may play an important role in the pathophysiology of motility in IBD. The pronounced increase in SP receptors at small vessels in all gut layers and at lymph nodules in the inflamed intestine of IBD patients supports the hypothesis that SP is a modulator of inflammation in IBD and possibly acts by release from extrinsic sensory nerves of the gut. Sensory nerve may play a role not only in enhancing an inflammatory response in the intestine, but also in tissue repair. An inflammatory response after tissue injury and subsequent wound healing presumably is the normal response in healthy tissue. In IBD however, this sequence may be deeply disturbed by an unrestricted immune response which does not lead to or delays intestinal tissue healing. Although it is intriguing to postulate that interactions between the immune system and nervous system exist and play a role in the pathophysiology of intestinal inflammation, in vivo studies blocking or mimicking neuropeptide action are needed to prove this bidirectional communication.
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PMID:Neuropeptides and inflammatory bowel disease. 171 64

The inherent variability of symptoms and motor abnormalities in patients with the irritable bowel syndrome has hampered the demonstration of motor abnormalities that could underlie symptoms. The aim in the current study was to evaluate whether altered regional capacitance or transit of solid residue through the unprepared human gut were factors in the diarrhea of patients with the irritable bowel syndrome. In 10 such patients and in 5 healthy controls, gastric and small bowel transits were evaluated scintigraphically by means of a mixed meal containing 99mTc-labeled resin pellets. Regional colonic transit was quantitated by 111In-labeled pellets delivered to the ileocecal region by a pH-sensitive, methacrylate-coated capsule. Symptomatic patients did not have significantly altered gastric or small bowel transits, but colonic transit was accelerated in 7 of 10 persons with the irritable bowel syndrome (P less than 0.02), in the proximal colon of five patients and in the left colon of two patients. The 24-hour stool weight was positively correlated with the rate at which solid residue emptied from the ascending and transverse colons (r = 0.78; P less than 0.01). There was also an inverse relationship between emptying rates and maximal volumes accommodated by the proximal colon (r = -0.58; P less than 0.05), although the maximum volume of the proximal colon was not significantly different in patients and healthy subjects. Thus, accelerated transit through the proximal colon is a factor in the pathophysiology of the irritable bowel syndrome and influences the stool weight of such patients. The capacitance of the proximal colon presumably influences its storage capacity and, hence, the rate at which it empties.
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PMID:Transit through the proximal colon influences stool weight in the irritable bowel syndrome. 172 43

Food allergy, synonymous with food hypersensitivity (FHS), is defined as an immunologically-mediated adverse reaction to food. Initiation of FHS could result from a break in the immune mucosal barrier with abrogation of oral tolerance. Food hypersensitivity is mostly due to immediate-type reaction involving IgE-dependent mastocytes activation. Changes in intestinal function and structure have been mainly studies in an animal model of rat sensitized to egg albumin. Intraluminal antigen challenge resulted in abnormalities of gut absorption, secretion and motility in sensitized rats. In man, experimental data are scarce. Gastrointestinal manifestations of immediate FHS are varying and unspecific. A role for FHS in irritable bowel syndrome is debated. Participation of delayed-type FHS to digestive diseases is still questionable, but eosinophilic gastroenteritis might be an example. In clinical practice, diagnosis of FHS demands rigorous criteria. Double blind placebo-controlled food challenge has eventually proved to be the "gold standard" test for FHS diagnosis.
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PMID:[Digestive manifestations of food hypersensitivity in adults]. 175 69

Although most T cells express the alpha/beta TCR, the gamma/delta TCR is expressed only on a small percentage of peripheral lymphocytes and CD3+ intestinal T cells. The most striking feature is a wide variation in the proportion of gamma/delta+ T cells in freshly isolated peripheral blood cells from normal individuals and patients with IBD. The augmentation of the gamma/delta+ T cell subpopulation derived from human intestinal biopsies after repeated stimulation with MT, even in the absence of filler cells, suggests that gamma/delta+ cells from human gut mucosa may play a role in generating a primary immune response to MT.
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PMID:Expression of gamma delta T lymphocytes derived from human intestinal biopsies. 183 84

The criteria now used in an attempt to distinguish irritable bowel syndrome from organic gastrointestinal disease rely almost entirely on symptoms of colonic origin. 'Non-colonic' symptoms, however, arising either from elsewhere in the gut or of a more general nature, are common in irritable bowel syndrome and may have even better diagnostic potential. The prevalence of these non-colonic features was assessed in 107 patients with the irritable bowel syndrome and 295 subjects with other gut disorders. Gastrointestinal type non-colonic symptoms are useful in differentiating irritable bowel syndrome from inflammatory bowel disease but, with the exception of early satiety, are not helpful when there is gastro-oesophageal or biliary disease. More general 'non-colonic' features, such as lethargy and backache, are much commoner in irritable bowel syndrome than in all the organic gastrointestinal diseases studied and have good discriminant function. Multiple logistic regression analysis identified certain features that had a particularly significant independent risk for irritable bowel syndrome. Those were lethargy (relative risk 6.7), incomplete evacuation (RR 5.2), age under 40 (RR 2.1), backache (RR 2.0), early satiety (RR 1.8), and frequency of micturition (RR 1.8). These relative risks can be multiplied together to give an overall risk when more than one of these features is present in a patient. Until a diagnostic test is available more confident diagnosis of irritable bowel syndrome can be achieved by identifying symptoms that have good discriminant function. The results of this study indicate that the non-colonic features of irritable bowel syndrome may be especially valuable in this respect.
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PMID:More accurate diagnosis of irritable bowel syndrome by the use of 'non-colonic' symptomatology. 156 69

We examined whether patients with irritable bowel syndrome have increased airway responsiveness by measuring forced expiratory volumes in 1 second (FEV1) after inhalation of increasing concentrations of methacholine. Responses obtained in 11 IBS patients were compared with those obtained in 11 normal subjects and in 11 subjects with organic disease of the gut or its related organs. All subjects were selected so that other factors that might contribute to increased airway responsiveness were excluded. The methacholine concentration that caused a 20% fall in the FEV1 (PC20), as well as the reduction in FEV1 induced by each methacholine concentration, were used to assess airway responsiveness. The geometric mean PC20 was 197.6 mg/mL (%SEM, 1.15) for normal subjects, 83.9 mg/mL (%SEM, 1.51) for subjects with organic bowel disease (P = 0.012), and only 12.8 mg/mL (%SEM, 1.74) for IBS patients (P less than 0.0001). The 22.5% +/- 2.5% decrease in FEV1 induced by 64 mg/mL of methacholine in IBS patients was significantly greater than that of 12.3% +/- 1.5% observed in healthy subjects (P = 0.003). In contrast, the 15.7% +/- 2.0% decrease in FEV1 observed in patients with organic disease was not different from that seen in normal subjects (P = 0.189). We conclude that IBS is associated with increased airway responsiveness following challenge with methacholine.
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PMID:Airway responsiveness to inhaled methacholine in patients with irritable bowel syndrome. 198 50


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