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

The impact of malnutrition on peptide and amino acid absorption has been studied in the immediate postweaning period. At this time peptide uptake is quantitatively more important than amino acid uptake and the vulnerability of the infant to malnutrition is great. Everted rings of rat jejunum were used to investigate the uptake of the peptide glycylsarcosine (Gly-Sar) and the amino acid L-leucine. The animals had been weaned on to isocaloric diets containing 18% or 4% protein. The rats deprived of protein at this age showed a marked growth disturbance with considerable reduction in gut length in addition to poor weight gain. Mediated influx of Gly-Sar and leucine per centimeter of jejunum was reduced in the malnourished animals: Vmax, 77 +/- 7.1 (SEM) and 65 +/- 3.6 compared with 85 +/- 10.6 and 77 +/- 4.4 nmol . min-1 . cm-1., respectively. But, when expressed in relation to body weight, the maximal transport capacity showed a marked increase with malnutrition, values being 126 and 111 nmol-1 . cm-1 . 100 g-1 body weight compared with 39 and 35 nmol-1 . cm-1 . 100 g-1 body weight for Gly-Sar and leucine respectively.
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PMID:Kinetics of uptake of L-leucine and glycylsarcosine into normal and protein malnourished young rat jejunum. 642 21

Etched frozen hydrated specimens of mouse small intestine have been examined with low temperature scanning electron microscopy as a preliminary to X-ray microanalysis. Recognizable images have been obtained of most of the known histological features of the gut. Nuclear and cytoplasmic details were often seen. Ice crystal damage was evident, although the degree of artefact depended on the cell type being examined and also varied from cell to cell or within cells. The same specimens were later examined with resin light microscopy and transmission electron microscopy. These two techniques confirmed that preservation was adequate for identification of cells and tissues, although cavities were seen, representing ice crystal damage. These preliminary results indicate that SEM of etched, frozen, hydrated specimens provides adequate identification of cellular detail to allow further work using X-ray microanalysis to be carried out.
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PMID:Low temperature scanning electron microscope studies of mouse small intestine. 664

Clinical and physiological studies were carried out in five patients with pneumatosis coli in order to investigate the origin of the high fasting breath hydrogen concentration in this condition and to determine its possible significance in the pathogenesis of the disease. All five patients excreted abnormally high fasting concentrations of hydrogen in their breath (69 +/- 9 ppm, mean +/- SEM). Moreover, analysis of the contents of the gas filled cysts revealed between 2% and 8% of hydrogen gas. Colonic washout significantly reduced breath hydrogen concentrations to 9 +/- 6 ppm, but did not abolish the cysts. Conversely, deflation of the cysts was achieved with oxygen or antibiotics, though this only reduced breath hydrogen concentrations to about 66% of their original value. After feeding a radiolabelled meal, breath hydrogen concentrations rose before the meal appeared to reach the colon, suggesting overgrowth of anaerobic bacteria in the small intestine. Despite this, 14C glycocholate breath tests were within normal limits. An alternative possibility is that the high levels of hydrogen excreted in the breath may be produced in the intestinal lumen possibly from the fermentation of copious amounts of colonic mucus. Finally, measurement of whole gut transit time and stool weight suggested that patients were constipated despite passing mucus and blood. The relevance of our observations to the pathogenesis of submucosal cysts is unclear, but the data favour the hypothesis that these are produced by invasion of the colonic submucosa with anaerobic bacteria.
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PMID:Is raised breath hydrogen related to the pathogenesis of pneumatosis coli? 674 22

The plasma concentrations of gastrin, gastric inhibitory polypeptide (GIP), gut glucagon-like-immunoreactivity (gut GLI), insulin, glucagon, and pancreatic polypeptide (PP) were studied following the ingestion of a protein rich meal in late pregnancy and postpartum in 11 normal women. In pregnancy, the fasting plasma concentrations of glucose (mean +/- SEM in pregnancy: 4.1 +/- 0.1 mmol l-1, postpartum: 4.7 +/- 0.1 mmol l-1, P less than 0.01), gut GLI (25 +/- 3 v. 33 +/- 2 pmol-eqv l-1, P less than 0.01), and PP (7.9 +/- 1.0 v. 13.0 +/- 1.2 pmol l-1, P less than 0.01) were decreased, gastrin and GIP unaltered, and insulin (90 +/- 9 v. 72 +/- 5 pmol l-1, P less than 0.05) and glucagon (17 +/- 1 v. 13 +/- 1 pmol l-1, P less than 0.01) increased. The gastrin, GIP and glucagon responses to the meal were unaffected by pregnancy, whereas the responses of gut GLI (integrated responses in pregnancy: 1217 +/- 325 pmol-eqv l-1, postpartum 2223 +/- 404 pmol-eqv l-1, P less than 0.05) and PP (9801 +/- 1440 v. 14,078 +/- 1543 pmol l-1, P less than 0.01) were impaired and the insulin response enhanced (27,973 +/- 6814 v. 11,409 +/- 3102 pmol l-1, P less than 0.01) in pregnancy. The physiological implications of these findings are at present not known in detail. They may, however, be important for the altered carbohydrate metabolism in pregnancy and also for the changes occurring during gestation in gastrointestinal physiology.
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PMID:Gastro-entero-pancreatic hormones in normal pregnancy: response to a protein rich meal. 680 Aug 4

Hypocholesterolaemia and high faecal elimination of cholesterol was explored by measuring the percentage of cholesterol absorbed, faecal steroids, serum cholesterol and dietary cholesterol in patients with coeliac disease before and after a gluten free diet. From these data, the total and endogenous flux of cholesterol into the gut and the amount of cholesterol absorbed could be calculated. The mean faecal bile acid excretion was normal, but faecal endogenous steroids and thus faecal total steroids, and the cholesterol synthesis, were increased in the patients. The percentage of cholesterol absorbed was quite low (15.1 +/- 2.1 (SEM) v. 34.1 +/- 2.5 in the controls), and it was attributable to a mucosal damage in the upper small intestine, suggesting that this played a primary role in the high faecal sterol loss. However, the influx of endogenous cholesterol into the gut had increased, so that in absolute terms the absorption of cholesterol was low only inconsistently. The gluten-free diet caused the opposite changes in the absorption percentage and influx of cholesterol into the gut, while the amount of cholesterol absorbed was only insignificantly increased. Serum cholesterol was significantly correlated with the cholesterol absorbed (r = 0.36; P less than 0.01), faecal endogenous steroids (r = -0.30; P less than 0.05), and cholesterol synthesis (r = -0.29; P less than 0.05). Furthermore, the rise in serum cholesterol during the gluten-free diet correlated negatively with the changes in cholesterol (r = -0.55; P less than 0.05) and bile acid (r = -0.77; P less than 0.01) synthesis. These associations and the lack of correlations between the amounts of cholesterol absorbed and synthesized suggest that the serum cholesterol level and regulation of cholesterol synthesis are interrelated in coeliac disease.
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PMID:Cholesterol absorption, elimination and synthesis in coeliac disease. 681 19

In our earlier investigations it has been shown that the gastrointestinal (GI) tract of the infant mouse (4-5 days old) can be colonized following a single intragastric challenge with Candida albicans. This makes it possible to investigate the sequence of events which occur during colonization of the GI tract by this opportunistic yeast. Two strains of C. albicans, CA 30 and NS 33, which were shown in earlier studies to differ markedly in their ability to persist in the GI tract were examined. The SEM was used to reveal the location of the yeast and their structural association with the surface of tissues of the gut at early times after intragastric inoculation. Animals were sacrificed after challenge, the GI tract was removed from each mouse and subdivided into the stomach, upper intestine, mid-intestine, ileum, cecum and large bowel. The number of colony forming units was determined by homogenizing these segments and plating them out on sabouraud's dextrose agar. The microenvironment of each segment was preserved by freezing samples in liquid nitrogen prior to processing for the SEM. The distribution and level of counts of the strains studied in the GI tract were comparable during the three week period. Both strains of C. albicans associated with the secreting epithelium and the keratinized epithelium of the stomach. Yeast also associated with the mucus layer and the epithelial surface throughout the GI tract. Those yeast adhering to the epithelial surfaces of the GI tract were frequently covered by a layer of mucus which may aid in colonization.
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PMID:SEM studies of adherence of candida albicans to the gastrointestinal tract of infant mice. 733 May 94

The possible involvement of nerves containing vasoactive intestinal polypeptide in Crohn's disease was investigated by immunocytochemistry and radioimmunoassay of specimens from 17 patients with well-defined clinical and histologic features of the disease. The characteristic pattern of slender fibers, evenly distributed across the gut wall, was seen in specimens taken from controls, which consisted of (a) specimens from uninvolved areas of gut from carcinoma resection (n = 17) and (b) jejunoileal specimens obtained during bypass operation for obesity (n = 8) as well as in four of the six specimens from patients with ulcerative colitis. In contrast, this characteristic pattern was lost in all 17 patients with Crohn's disease, the pattern being replaced by thickened and more intensely immunostained fibers. These changes were consistently found in the mucosa and submucosa, and in 13 of the Crohn's disease cases, the abnormal pattern was totally transmural, involving both the myenteric and submucous plexus as well as the muscle layers. There was a > 200% increase in VIP content, as determined by radioimmunoassay, in Crohn's disease (294 +/- 29 pmol/g wet wt, mean +/- SEM) in comparison with (a) ulcerative colitis (93 +/- 5 pmol/g [P < 0.001]), and (b) controls consisting of carcinoma resection (108 +/- 39) and bypassed gut from obese patients (86 +/- 27 [P < 0.001]). At least part of the previously documented autonomic nerve changes in Crohn's disease are, thus, due to an increase in vasoactive intestinal polypeptide innervation.
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PMID:Abnormalities of vasoactive intestinal polypeptide-containing nerves in Crohn's disease. 741 8

1. Intravenous infusions of the brain/gut hormone, cholecystokinin, have been shown to reduce food intake in a subsequent test meal. However, in previous studies the doses administered were large and likely to have produced plasma concentrations far in excess of the normal post-prandial range. 2. In this study cholecystokinin-8 was infused intravenously to six healthy subjects in doses that reproduced physiological post-prandial concentrations. Plasma concentrations of cholecystokinin were measured using a novel sensitive and specific radioimmunoassay. The effect of cholecystokinin-8 infusion on subsequent food intake in a standard test meal was compared with the effect of saline infusion in the same subjects. 3. Food intake (mean +/- SEM) was significantly less during cholecystokinin (5092 +/- 665 kJ) than during saline infusion (6418 +/- 723 kJ, P = 0.03). During cholecystokinin infusion, plasma concentrations increased from 0.45 +/- 0.06 pmol/l to 7.28 +/- 2.43 pmol/l immediately before the meal. With saline infusion there was no premeal increase in plasma cholecystokinin concentration. 4. This paper describes a novel radioimmunoassay for measurement of plasma concentrations of cholecystokinin. Using this assay we have demonstrated that cholecystokinin is important in control of satiety in humans.
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PMID:Cholecystokinin is a satiety hormone in humans at physiological post-prandial plasma concentrations. 749 37

Bran is an effective treatment for constipation but its use is often limited by heartburn and bloating. This study examined the effect of fine and coarse bran (15 g) on the gastric emptying and small bowel transit of a 325 kcal rice test meal. Twelve healthy volunteers underwent a three way cross over study, ingesting the technetium-99m labelled rice meal with or without 15 g of indium-111m labelled fine or coarse bran, in random order. Serial scintigraphic images were obtained to define gastric emptying and colonic arrival of label. Compared with control values (99 (9) minutes) (mean (SEM)), the time to 50% gastric emptying was significantly delayed by coarse but not fine bran, being 121 (6) and 104 (9) minutes respectively, p < 0.05, n = 12. Fundal emptying was unchanged but both brans seemed to increase the proportion of isotope in the antrum at 90 minutes. Small bowel transit was slightly faster with both bran types but in this study the difference was not significant. Both the bran and rice labels moved down the gut without significant separation. Fine bran causes less disturbance of gastric physiology than coarse bran.
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PMID:Effect of bran particle size on gastric emptying and small bowel transit in humans: a scintigraphic study. 755 71

On the basis of recent findings that adult black women had similar calcium absorption but higher levels of 1,25-dihydroxyvitamin D [1,25-(OH)2D] than white women, we hypothesized that blacks have a gut resistance to the action of calcitriol. To test this, we studied 11 black [age, 32.4 +/- 5.7 (+/- SD) yr] and 12 white women (28.4 +/- 5.5 yr). The women were maintained on a constant 500-mg calcium diet for 4 weeks, and each received calcitriol (0.25 microgram) four times daily for the last 2 weeks. After 2 and 4 weeks, each subject had measurements of fractional 45Ca absorption index and blood and urine tests. At 2 weeks, the black women had similar calcium absorption indexes [18.7 +/- 1.9% (+/- SEM)/L vs. 20.0 +/- 1.8%/L; age adjusted], borderline higher 1,25-(OH)2D levels [95.7 +/- 6.4 (+/- SEM) vs. 78.2 +/- 6.2 pmol/L; P = 0.071; age adjusted], higher serum PTH levels, and lower urinary calcium excretion. Calcitriol therapy induced similar increments in plasma 1,25-(OH)2D levels in the two groups, but a smaller increment in calcium absorption in the black women (18.4 +/- 8.6% vs. 44.6 +/- 7.8%; P = 0.043; means adjusted for age and initial absorption index). These findings support the hypothesis that, compared with whites, healthy premenopausal black women have gut resistance to the action of calcitriol.
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PMID:Calcium absorption responses to calcitriol in black and white premenopausal women. 755 98


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