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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of lamina propria cells in regulating human colonic ion transport was investigated in vitro. Normal human colonic mucosae were mounted in Ussing chambers, and short circuit current changes (delta SCC) were monitored in response to immune cell activation. Anti-human immunoglobulin E (anti-IgE) and formyl-Methionyl-Leucyl-Phenylalanine (fMLP) were used to stimulate mast cells and phagocytes respectively. Anti-IgE (100 micrograms/ml) and fMLP (100 microM) evoked rapid onset, inward delta SCC (mean (SEM) max delta SCC 19.3 (2.8) and 29.4 (4.7) microA/0.63 cm2 respectively). A pharmacological approach was used to identify the charge carrying ion species and to characterise mediators involved in the SCC response. Responses to each secretagogue were significantly attenuated by bumetanide, indicating that the delta SCC was at least partly due to electrogenic chloride secretion. Piroxicam reduced the delta SCC to mast cell and phagocyte activation by 91.1 (3.4)% and 48.2 (25.2)% respectively, implicating eicosanoids as mediators of the responses. Mepyramine (100 microM) reduced the SCC responses to anti-IgE by 79.6 (12.0)% but did not significantly alter delta SCC responses to fMLP. Desensitisation to repeated anti-IgE or fMLP stimulation, and cross desensitisation between each of the stimuli, were features of immune cell activation. In summary, we have shown that activation of immune cells can stimulate electrogenic chloride secretion. Such events in vivo will result in gradient driven secretory diarrhoea, which may occur as a protective response to enteric-dwelling parasites, or as a feature of local bowel inflammation.
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PMID:Immune regulation of human colonic electrolyte transport in vitro. 769

Following the acute diarrhea in patients (n = 24) overnight with commonly used laxatives for bowel preparation, the changes in electrolytes and acid-base balance in blood and urine were investigated. Though no alterations of serum sodium or potassium concentrations were noted, mild but significant reduction of mean values (+/- SEM) of plasma pH and HCO3 after diarrhea when compared to those before it developed (pH, from 7.42 +/- 0.01 to 7.39 +/- 0.01, p < 0.01; HCO3, from 25.8 +/- 0.6 to 23.7 +/- 0.6 mEq/L, p < 0.05). However, significant reduction of concentration in spot urine sodium from 150 +/- 12.3 to 93 +/- 14 mEq/g of crea. (p < 0.01) and increase in spot urine potassium from 33 +/- 3.2 to 51 +/- 6.0 mEq/g of crea. (p < 0.05) following diarrhea were seen with significant reduction of urine pH from 6.67 +/- 0.21 to 5.5 +/- 0.13 (p < 0.001). Also, with this effective urinary acidification following diarrhea, a significant reduction of urinary anion gap as well as significant increment of spot urine ammonium was accompanied (anion gap, from 80.4 +/- 11.1 to 44 +/- 8.5 mEq/g of crea. p < 0.001; ammonium, from 87 +/- 18.5 to 229 +/- 37 mg/g of crea. p < 0.001) in addition to the significant inverse correlation between these changes in spot urine from basal levels in 24 study subjects (y = -1.13 x +61, r = 0.7, p < 0.001). In conclusion, we observed that the acute diarrhea with laxatives used for bowel preparation caused a mild degree of metabolic acidosis with no changes in blood electrolytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The changes in electrolytes and acid-base balance after artificially induced acute diarrhea by laxatives. 770 87

Incubation of human colonic contents with various ethanol concentrations (2.75-44 mM) in vitro at 37 degrees C resulted in significant accumulation of acetaldehyde--a toxic and highly reactive compound. At pH 9.6, all samples produced notable acetaldehyde concentrations (58 (13) microM; mean (SEM)) even from the lowest (2.75 mM) ethanol concentration, and the production of acetaldehyde increased lin-early with rising ethanol concentration (r = 0.97; p < 0.005), reaching a peak concentration of 238 (37) microM at 44 mM ethanol. The formation of acetaldehyde took place rapidly, as almost 50% of acetaldehyde formed during the total eight hour incubation was detectable after one hour, and 75% of the total after four hours. Maximal acetaldehyde production from 22 mM ethanol occurred at pH 9.6 (160 (35) microM) but appreciable concentrations were also seen at pH 7.4 (110 (38) microM) and pH 6.0 (63 (19) microM). At pH 4.0, by contrast, acetaldehyde formation was negligible (17 (5) microM). 4-Methylpyrazole, a potent inhibitor of alcohol dehydrogenase, showed a decreasing effect on acetaldehyde production in vitro but first at a concentration of 100 mM. Considerable acetaldehyde production by human colonic bacteria--if it occurs also in vivo--could constitute a risk factor for rectal cancer in heavy drinkers and also provide a pathogenetic mechanism for alcohol induced diarrhoea.
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PMID:In vitro acetaldehyde formation by human colonic bacteria. 795 36

Dietary supplementation with fish oils high in the omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, may have an antiinflammatory effect. We determined whether patients with cystic fibrosis (CF) could incorporate omega-3 fatty acids into their plasma and cell membrane phospholipids without adverse effects. In this double-blind study, 12 patients with pancreatic insufficiency who have CF (mean age, 12.2 +/- 5.4 (SD) years) and 13 subjects without CF (mean age, 13.4 +/- 6.3 (SD) years) were randomly assigned to ingest 8 gm daily of either encapsulated fish oil (3.2 gm of eicosapentaenoic acid and 2.2 gm of docosahexaenoic acid daily) or olive oil ethyl esters for 6 weeks. Two of seven and two of five patients with CF who received fish and olive oils, respectively, and one of eight and none of five subjects without CF discontinued taking the capsules before 6 weeks because of eructation or diarrhea. Significant incorporation of omega-3 fatty acids into plasma and erythrocyte membrane phospholipids was observed in subjects with and those without CF randomly assigned to the fish oil treatment. For example, in subjects randomly assigned to receive fish oil, the eicosapentaenoic acid/arachidonic acid ratio in plasma increased 9.8-fold, from 0.04 +/- 0.02 (mean +/- SEM) to 0.39 +/- 0.11 (p = 0.02), in the patients with CF (n = 7) and 23.0-fold, from 0.04 +/- 0.01 to 0.92 +/- 0.17 (p = 0.001), in the subjects without CF (n = 8) who received fish oil (p = 0.02, patients with CF vs subjects without CF at 6 weeks). No clinically or statistically significant changes from baseline were observed in platelet aggregation or levels of vitamin E or A in subjects who received fish oil. Future studies are indicated to determine whether omega-3 fatty acid enrichment provides a clinically beneficial antiinflammatory effect in patients with CF.
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PMID:Oral absorption of omega-3 fatty acids in patients with cystic fibrosis who have pancreatic insufficiency and in healthy control subjects. 807 70

1. Unlike standard glucose-electrolyte oral rehydration solutions, solutions containing polymeric glucose as substrate can significantly reduce stool output, duration of diarrhoea and total oral rehydration solution requirements. However, neither the underlying mechanisms nor the optimal size and concentration of glucose polymer has been defined. 2. We have used a model of rotavirus diarrhoea in neonatal rats to compare the effects on water and solute absorption of varying the concentration of a glucose polymer (mean chain length five glucose residues) in experimental oral rehydration solutions. Three polymer (P) solutions were compared with solutions of identical electrolyte content (mmol/l: sodium, 60; potassium, 20; chloride, 60; citrate, 10) containing equivalent amounts of free glucose (G) as substrate by perfusion of the entire small intestine in situ. The polymer (9, 18, 36 mmol/l; 159, 168, 186 mosmol/kg, respectively) and the monomer (45, 90, 180 mmol/l; 195, 240 320 mosmol/kg) solutions were perfused in normal and rotavirus-infected neonatal rats. 3. In normal intestine polymer solutions promoted greater water absorption [P9, mean 291.4 (SEM 16.4); P18, 331.9 (13.1); P36, 284.3 (11.8) microliters min-1 g-1] than their equivalent monomer solutions [G45, 220.8 (8.4); G90, 240 (21); G180,79.4 (14.5) microliters min-1 g-1; P < 0.02]. In rotavirus-infected intestine, water absorption from all solutions declined, but the fall was much less pronounced from the polymer solutions [P9, 232.8 (6); P18, 277.2 (20.5); P36, 166 (18.2) microliters min-1 G-1] than from their monomeric counterparts [G45, 116.7 (25.5); G90, 68.7 (12.4); G180, 21 (11.6) microliters min-1 g-1; P < 0.005].(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glucose polymer in the fluid therapy of acute diarrhoea: studies in a model of rotavirus infection in neonatal rats. 816 43

The motor patterns and luminal capacity of the human intestine should affect symptoms and resorption during pathological, massive small intestinal flow. Little is known of human intestinal motility in this situation. This study aimed at mimicking secretory diarrhoea (experimentally) in healthy volunteers by intrajejunal infusion of a non-absorbable iso-osmotic solution at 20 ml/min. During the infusion intraluminal jejunal pressures and small intestinal transit times were measured. The infusion initially caused jejunal contractile activity similar to that of the fed state but this was replaced by discrete clusters of contractions (DCCs) after 29.1 ((SEM) 8.2) minutes. DCCs each lasted 38 ((SEM) 0.8 seconds) and were associated with colicky abdominal discomfort. Later, after 1400-1800 ml had been infused, distal jejunal pressure waves fell to 10 mm Hg or less. Frequent fasting DCCs predicted earlier onset and more frequent DCCs during the infusion. Thus, the rate and volume of flow during simulated secretory diarrhoea determine the pattern of the small bowel pressure profile; eventually, a volume load is reached in which the small bowel acts as a poorly segmenting conduit resulting in very fast transit rates.
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PMID:Response of the human intestine to high volume infusion. 820 May 57

The effects of the 5-hydroxytryptamine (5-HT3) receptor antagonist, ICS 205-930 (tropisetron), on basal and 5-HT induced jejunal secretion of water and electrolytes were examined using a double blind, randomised crossover design. In seven healthy volunteers steady state perfusions of the proximal jejunum were performed twice with the Loc-I-Gut tube after 5+5 mg ICS 205-930 or placebo capsules were given. After equilibration for 60 minutes and completion of a 120 minute basal period 5-HT (10 micrograms/kg x min intravenously) was infused for 120 minutes. Net water absorption (mean (SEM)) in the basal period was 0.55 (0.84) ml/cm x h and 0.74 (0.72) ml/cm x h after placebo and ICS 205-930, respectively (p > 0.05). Infusion of 5-HT caused significant net secretion of water after placebo (2.05 (0.58) ml/cm x h; p < 0.02) as well as ICS 205-930 (2.60 (0.89) ml/cm x h; p < 0.05). As ICS 205-930 excerted no effects on either basal or 5-HT induced water and electrolyte transport in the intact human jejunum the compound is probably not efficacious as an anti-secretory drug in patients with 5-HT induced diarrhoea.
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PMID:Failure of tropisetron to inhibit jejunal water and electrolyte secretion induced by 5-hydroxytryptamine in healthy volunteers. 820 May 56

Dysmotility of the duodenum and proximal jejunum has been reported in patients with irritable bowel syndrome. This study extended these findings by recording fasting ambulatory motility from electronic strain gauge sensors sited in the jejunum and ileum of eight diarrhoea predominant irritable bowel syndrome patients and 12 healthy controls. During the day, periodicity of migrating motor complexes mean (SEM) did not differ between patients (92 (10) min) and controls (85 (7) min). At night, periodicity was shorter in both patients and controls, and the daytime dominance of phase II was replaced by phase I. In both groups, aboral progression of phase III fronts was associated with a slowing of propagation velocity and maximum contractile rate, but an increase in mean amplitude of contraction. Discrete clustered contractions were seen in seven patients and 10 controls occupying 14 and 16% of daytime phase II activity, respectively. Pain episodes were not associated with any specific motility patterns. Despite the lack of motility differences between the two groups, orocaecal transit time in the irritable bowel syndrome patients was shorter at 57 (9) min than in the controls, 82 (6) min (p < 0.05). This ambulant study has failed to show any abnormalities of fasting small intestinal motility that might distinguish diarrhoea predominant irritable bowel syndrome patients from healthy controls.
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PMID:Ambulatory small intestinal motility in 'diarrhoea' predominant irritable bowel syndrome. 830 70

Antisecretory factor (ASF) is a regulatory peptide which counteracts diarrhoea in the pig; ASF is rapidly absorbed from the pig intestine, and significantly reduces the incidence of neonatal diarrhoea in the suckling offspring. ASF is synthesized in the central nervous system, and released to the blood stream via the pituitary gland. In two different experiments (n = 8 and n = 4), the blood concentration of ASF was followed in 5-weeks old piglets from day 7 before weaning up to day 12 days after weaning. In both experiments ASF concentrations were significantly (p < 0.01) lower on day three post-weaning, than either before weaning or on days 7 and 12 post-weaning. In another experiment, where plasma ASF activity was determined in relation to clinical signs of diarrhoea seven days post-weaning, it was found to be 0.87 +/- 0.08 units/ml (mean +/- SEM) in healthy weaners (n = 15), but only 0.22 +/- 0.05 units/ml in piglets suffering from diarrhoea (n = 15), the difference being significant. The faecal flora both of healthy weaners and of their matched controls suffering from diarrhoea were subjected to bacteriological examination before and after weaning, and found to be similar in both groups, namely a mixture of aerobic and anaerobic Gram negative rods, Campylobacter jejuni, Staphylococcus aureus/epidermidis, and Enterococcus faecalis. No particular pathogen was predominant in any of the diseased animals.
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PMID:Plasma level of antisecretory factor (ASF) and its relation to post-weaning diarrhoea in piglets. 832 43

Terminal ileal biopsies were prospectively obtained and stained specifically for mast cells in 20 patients with irritable bowel syndrome (IBS) and 15 controls. The number of terminal ileal mast cells per high powered field (MC/HPF) (mean +/- SEM) was 23.3 +/- 3.1 for IBS and 6.8 +/- 1.1 for controls (P = 0.0001). The diarrhea IBS subgroup had the greatest number of MC/HPF. No correlation was found between terminal ileal mucosal mast cell counts (MMCC) and the number of Manning criteria present or the functional bowel disease score (r = 0.06 and r = -0.31, respectively). We conclude that terminal ileal MMCC are significantly elevated in a majority of patients with IBS. The mast cell may be responsible for the altered visceral perception found in the gastrointestinal tract in patients with IBS. The poor correlation of the MMCC to the clinical features of IBS may be the result of the dynamic state of the mast cell.
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PMID:Terminal ileal mucosal mast cells in irritable bowel syndrome. 835 68


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