PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Intestinal Mucosa”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1987

Opioid action of the intestine: the importance of the intestinal mucosa.

Drug effects on the intestine are traditionally explained in terms of action on the muscle layers and the nerves that control them. This is particularly true in the case of the opioids but research starting two decades ago has identified the intestinal mucosa as the site of action of the antidiarrhoeal opioids. Continued research using the intestinal mucosa offers a fresh approach to solving some old problems. For example it could lead to more confident predictions to be made about the wanted and unwanted effects of opioid drugs on the intestine and may help to find better drug treatments for alleviating withdrawal diarrhoea in addicts. Eventually it may help to explain how the general process of opioid dependence occurs at a cellular level.

Antidiarrheals↗
PubMed1984

[Remarkable microbial findings in the small intestine mucosa of children].

In intestinal specimens of children repeatedly attacked by enteritis electron microscopic investigations were practiced. In 26% of biopsies mycosis was found and in 72% a bacterial infection of the intestinal mucosa. We found narrow contacts between the infectious agents and the mucosa by electron microscopic evaluation (adhesion, penetration, partly thick layers). The microbes found are suitable to maintain the recurring cases of diarrhoea. Our results demand an exact antibiotic and antimycotic therapy.

Child↗
PubMed1975

[Ultrastructural and cytochemical study of the endocrine serotonin secreting cells of the fetal and adult rabbit intestinal mucosa].

Endocrine cells of intestinal mucosa have been studied in rabbit fetuses and adults. The problem of an ultrastructural identification of "preargentaffin" serotonin cells has been elucidated comparing cytochemical and ultrastructural datas. Since all cells exhibiting a yellow formaldehyde-induced fluorescence reacted with Sevier-Munger method and since all impregnated cells were fluorescent it has been concluded that impregnated cells at the electron microscope level are serotonin cells; these cells had generally small and round granules. Another cell type with small round granules showing deposition of silver grains on the outer rim has been identified as granular S cells.

Animals↗
PubMed2005

Lipid-soluble and water-soluble antioxidant activities of the avian intestinal mucosa at different sites along the intestinal tract.

The antioxidant capacity of the avian intestinal mucosa is potentially important in protecting the gut wall from the harmful actions of reactive oxygen species originating from the diet, mucosal metabolism and the inflammatory response to enteric microbes. To assess this capacity, we determined the total lipid-soluble and water-soluble antioxidant activities of mucosal extracts, using tissue from different parts of the intestinal tract of the chicken. The lipid-soluble antioxidants, vitamin E and carotenoids, were also measured in the same samples. Total lipid-soluble antioxidant activity was highest in mucosa from the duodenum followed by the jejunum, with much lower activities in the ileum, ceca and colon. Total water-soluble antioxidant activity of the mucosa was at least an order of magnitude greater than the lipid-soluble activity under the assay conditions and did not differ significantly among the different parts of the intestinal tract. High concentrations of vitamin E were present in the mucosa of the duodenum and jejunum, with a trend to lower levels in the ileum and ceca, and significantly less in the colon. Similarly, the mucosa of the duodenum and jejunum contained the highest concentrations of carotenoids, with much lower levels in the ileum and colon. The different isoforms of vitamin E were absorbed from the digesta by the mucosa without any major selectivity. However, the liver was greatly enriched with alpha-tocopherol over the other isoforms, indicating a high degree of discrimination by this tissue. The results indicate major differences in the relative contributions of lipid- and water-soluble antioxidants in the mucosa along the different parts of the intestinal tract, most likely reflecting the sites of vitamin E and carotenoid absorption.

Animals↗
PubMed1983

Pyrroline-5-carboxylate synthesis from glutamate by rat intestinal mucosa.

The mitochondria of rat intestinal mucosa were found to have an enzymatic activity that converts radioactive glutamate to pyrroline-5-carboxylate (P5C) in the presence of ATP, NADPH, and MgCl2. The product of this enzyme was identified as P5C by the fact that it was converted to proline by chemical reduction with NaBH4 or by enzymatic reduction with NADH in the presence of purified yeast P5C reductase. The product was demonstrated to be P5C rather than pyrroline-2-carboxylate by thin layer chromatography. The presence of the activity in mitochondria prepared from intestinal mucosa of germ-free rats proved that this activity is of mammalian origin. Omission of either ATP, NADPH, or MgCl2 from the reaction mixture resulted in little or no activity. The optimal pH appeared to be about 7.0 under the conditions used. Substrate saturation curves in the presence of an ATP and an NADPH regeneration system gave apparent Km values of 2.5 mM for glutamate, 0.19 mM for ATP, and 6.5 microM for NADPH in the presence of 20 mM MgCl2. The mitochondrial preparation usually produced P5C at a rate of 1.2 to 1.6 nmol/mg/min at 20 degrees C when incubated with 1 mM glutamate, 3 mM ATP, 0.2 mM NADPH, and 20 mM MgCl2.

Animals↗
PubMed1997

Transport, uptake, and metabolism of the bis(pivaloyloxymethyl)-ester prodrug of 9-(2-phosphonylmethoxyethyl)adenine in an in vitro cell culture system of the intestinal mucosa (Caco-2).

PURPOSE: To evaluate intestinal transport, uptake and metabolism characteristics of the bis(pivaloyloxymethyl)-ester [bis(POM)-ester] of the antiviral agent 9-(2-phosphonylmethoxyethyl)adenine [PMEA]. METHODS: Intestinal transport, uptake and metabolism of bis(POM)-PMEA were studied using an in vitro cell culture system of the intestinal mucosa (Caco-2 monolayers). Concentrations of bis(POM)-PMEA and its metabolites mono(POM)-PMEA and PMEA were determined using a reversed-phase HPLC method. Enzymatic stability of bis(POM)-PMEA was evaluated by incubation with purified liver carboxylesterase, homogenates of Caco-2 cells and scraped pig small intestinal mucosa. RESULTS: The use of bis(POM)-PMEA as a prodrug of PMEA resulted in a significant increase in transport of total PMEA [bis(POM)-PMEA, mono(POM)-PMEA and PMEA] across Caco-2 monolayers. While transepithelial transport of PMEA (500 microM) was lower than 0.1% during a 3 hr incubation period, transport of total PMEA after addition of bis(POM)-PMEA (100 microM) amounted to 8.8% over the same incubation period. Only 23% of the amount transported appeared as intact bis-ester at the basolateral side, while 33% of this amount was free PMEA and 44% was mono(POM)-PMEA, suggesting susceptibility of the prodrug to chemical and enzymatic degradation. Uptake studies revealed that only negligible amounts of bis(POM)-PMEA (< 0.2%) were present inside the cells. Very high intracellular concentrations of PMEA were found (approximately 1.2 mM, after a 3 hr incubation with 50 microM bis(POM)-PMEA), which suggests that PMEA was trapped inside the cells probably due to its negative charge. This explains that efflux of PMEA was relatively slow (25% of the intracellular amount in 3 hr). Enzymatic degradation of the prodrug by carboxylesterase was confirmed by incubation of bis(POM)-PMEA with purified enzyme (Km = 87 microM and Vmax = 9.5 microM/min). Incubation of bis(POM)-PMEA (10 microM) with cell homogenate of Caco-2 monolayers and pig small intestinal mucosa produced similar degradation profiles. CONCLUSIONS: The use of the bis(POM)-prodrug significantly enhances the intestinal permeability of PMEA. Intracellular trapping of PMEA in the intestinal mucosa may result in slow release of PMEA to the circulation after oral administration of bis(POM)-PMEA.

Adenine↗
PubMed2005

Weight loss and morphometric study of intestinal mucosa in rats after massive intestinal resection: influence of a glutamine-enriched diet.

UNLABELLED: Short-bowel syndrome is responsible for significant metabolic alterations that compromise nutritional status. Glutamine is considered an essential nutrient for enterocytes, so beneficial effects from supplementation of the diet with glutamine are hypothesized. PURPOSE: In this study, the effect of a diet enriched with glutamine was evaluated in rats undergoing extensive small bowel resection, with analysis of postoperative weight loss and intestinal morphometrics of villi height, crypt depth, and thickness of the duodenal and remnant jejunal mucosa. METHODS: Three groups of male Wistar rats were established receiving the following diets: with glutamine, without glutamine, and the standard diet of laboratory ration. All animals underwent an extensive small bowel resection, including the ileocecal valve, leaving a remnant jejunum of only 25 cm from the pylorus that was anastomosed lateral-laterally to the ascendant colon. The animals were weighed at the beginning and end of the experiment (20th postoperative day). Then they were killed and the remnant intestine was removed. Fragments of duodenal and jejunal mucosa were collected from the remnant intestine and submitted to histopathologic exam. The morphometric study of the intestinal mucosa was accomplished using a digital system (KS 300) connected to an optic microscope. Morphometrics included villi height, crypt depth, and the total thickness of intestinal mucosa. RESULTS: The weight loss comparison among the 3 groups showed no significant loss difference. The morphometric studies showed significantly taller duodenal villi in the glutamine group in comparison to the without glutamine group, but not different from the standard diet group. The measurements obtained comparing the 3 groups for villi height, crypt depth, and thickness of the remnant jejunum mucosa were greater in the glutamine-enriched diet group than for the without-glutamine diet group, though not significantly different from with standard-diet group. CONCLUSIONS: In rats with experimentally produced short-bowel syndrome, glutamine-enrichment of an isonitrogenous test diet was associated with an improved adaptation response by the intestinal mucosa but not reduced weight loss. However, the adaptation response in the group receiving the glutamine-enriched diet was not improved over that for the group fed regular chow.

Animals↗
PubMed2000

Phenotypical and morphological analyses of intraepithelial and lamina propria lymphocytes in normal and regenerating gastric mucosa of rats in comparison with those in intestinal mucosa.

While the intestine has abundant intraepithelial lymphocytes (IELs) including extrathymically differentiated T-cell populations and natural killer (NK) cells, the stomach contains only a few IELs. To elucidate whether the gastric epithelium is capable of inducing predominant lymphocyte lodging and subsequent differentiation within, we counted the number of IELs and lamina propria lymphocytes (LPLs) and calculated the percentage of IELs to total lymphocytes for each alpha-beta T cell, gamma-delta T cell, CD4+ cell, CD8+ cell and NK cell in normal and regenerating gastric mucosa as well as the intestinal mucosa of the rat. In the normal rat pylorus, a few alpha-beta T cells but no gamma-delta T cells were found in the epithelium and lamina propria. In regenerating gastric mucosa, all subsets of LPLs increased in number to a degree comparable to those in intestinal mucosa, whereas every IEL subset, though slightly increased, was much smaller in number than in the intestinal mucosa, consequently giving lower percentages of IELs. Electron microscopic observations revealed that all IELs in regenerating gastric mucosa were agranular, while 55% of intestinal IELs were large granular lymphocytes positively stained for an NK-cell, alpha-beta-cell or gamma-delta T-cell marker. The present results indicate that, unlike the intestinal epithelium, the gastric epithelium does not induce the preferential localization of T cells/NK cells and T-cell differentiation into granular lymphocytes in the epithelium even under conditions of prominent LPL infiltration.

Animals↗
PubMed1989

Further studies on the effect of aldosterone on Mg2+-HCO3(-)-ATPase and carbonic anhydrase from rat intestinal mucosa.

The main purpose of this study is to elucidate the effect of adrenocorticoids on Mg2+-HCO3(-)-ATPase and carbonic anhydrase which are thought to be related to anion transport in mammalian intestinal mucosa and renal tubulus. Rat duodenal mucosa, large intestinal mucosa and kidney cortex were excised and homogenized with mannitol-Tris buffer (pH 7.1) and brush border fraction and cytosol were obtained by a differential fractionation procedure. Brush border Mg2+-HCO3(-)-ATPase and cytosol carbonic anhydrase activities in the duodenal mucosa decreased to 70% and 37% of normal values, respectively 5-11 days after adrenalectomy. Adrenalectomy also decreased significantly both enzyme activities in large intestinal mucosa; on the other hand, renal enzyme activities did not change. Four hours after a single injection of 20-80 micrograms/kg of aldosterone, ip, to adrenalectomized rats, Mg2+-HCO3(-)-ATPase and carbonic anhydrase activities in duodenal mucosa increased gradually to normal or near normal in dose-dependent fashion. Both enzyme activities in large intestinal mucosa were also increased by a larger dose of aldosterone. Again, renal enzyme activities were not affected by any dose of aldosterone. In contrast, corticosterone (1 mg and 4 mg/kg) and dexamethasone (50 micrograms 200 micrograms/kg) had no replacement effect on enzyme activities in all organs. These results showed that the mineralocorticoid, but not glucocorticoids, is a regulator of the enzyme activity of Mg2+-HCO3(-)-ATPase and carbonic anhydrase from intestinal mucosa. The true mechanisms by which both enzymes are activated by aldosterone are not clear at present.

Adrenalectomy↗
PubMed1996

Adhesion of enteroaggregative Escherichia coli to pediatric intestinal mucosa in vitro.

Organ cultures of small- and large-intestinal mucosa from children were used to examine the interactions of enteroaggregative Escherichia coli (EAEC) with human intestine. Mucosae from patients aged between 3 and 190 months were cultured with five EAEC strains isolated from infants with diarrhea in the United Kingdom and with two well-described prototype EAEC strains, 17-2 and 221. The prototype strains adhered to jejunal, ileal, and colonic mucosae. The wild-type strains also adhered to this tissue but showed a variable pattern of adhesion: two adhered to all intestinal levels, one adhered to jejunum and ileum, one adhered to ileum only, and one adhered to ileum and colon. Adherence was in an aggregative or stacked-brick pattern, resembling that seen on HEp-2 cells. Electron microscopy of infected small intestinal mucosa revealed bacteria in association with a thick mucus layer above an intact enterocyte brush border, which contained extruded cell fragments. This mucus layer was not present on controls. EAEC adherence to colonic mucosa was associated with cytotoxic effects including microvillous vesiculation (but without evidence of an attaching/effacing lesion), enlarged crypt openings, the presence of intercrypt crevices, and increased epithelial cell extrusion. These results demonstrate that in vitro organ culture of intestinal mucosa from children can be used to investigate EAEC pathogenesis in childhood directly. EAEC strains appear able to colonize many regions of the gastrointestinal tract, without overt changes to small intestinal mucosa but with cytotoxic effects on colonic mucosa.

Adult↗
PubMed1991

Regulation of serotonin release from the intestinal mucosa.

In the mammalian intestine serotonin (5-hydroxytryptamine, 5-HT) is present in high concentrations in the enterochromaffin cells. The release of 5-HT from the intestinal mucosa is regulated by a complex pattern of neuronal and humoral inputs to the enterochromaffin cells. The enterochromaffin cells appear to be endowed with different inhibitory (alpha 2-adrenoceptors, GABAA- and GABAB-receptors, histamine H3-receptors, receptors for vasoactive intestinal polypeptide and somatostatin) as well as stimulatory receptors (beta-adrenoceptors, muscarine and nicotine receptors). The physiological significance of this complex system of receptors is suggested by experiments which demonstrate that the respective intrinsic neurotransmitters (catecholamines, acetylcholine, GABA and vasoactive intestinal polypeptide) released within the gut are involved in the regulation of the release of 5-HT from the enterochromaffin cells.

Animals↗
PubMed1983

Tissue specificity of human phosphodiesterase. II. Intestinal mucosa.

Extracts of human intestinal mucosa were examined for their ability to hydrolyze various phosphodiester, phosphomonoester and phenylphosphonate ester linkages. Enzymes carrying out these reactions were partially purified by butanol extraction, ammonium sulfate precipitation and DEAE-cellulose chromatography, and examined for polymorphism on polyacrylamide gels. Two species of alkaline phosphatase and at least five species of PDE I were identified. Antibodies to purified bovine intestinal phosphatase and phosphodiesterase were found specific for the respective human enzymes.

Alkaline Phosphatase↗
PubMed1990

[Microbiocenosis and the status of the intestinal mucosa in alkylosing spondyloarthritis].

Intestinal microbiocenosis was examined in 53 patients with ankylosing spondyloarthritis (AS). Of these, 23 had the central and 30 presented with the peripheral form. 34 patients underwent endoscopic examinations (rectoromanoscopy, ileocolonoscopy). As a result, in 74% of cases with the central form of AS and in 80% of cases with the peripheral form of AS, alterations in the intestinal microflora were revealed, which can be regarded as intestinal dysbacteriosis (ID), with dysbacteriosis being more pronounced in patients with the peripheral form. In such patients it manifested by a considerable decrease of the amount of bifido- and lactoflora, which promoted the increment of the amount of opportunistic microorganisms, particularly Klebsiella. Macroscopic signs of nonspecific inflammation of the small and large intestines were identified in 63% of patients with the central and in 67% of those with the peripheral form of AS. Mean-while histomorphological study of biopsy specimens of the intestinal mucosa showed that all the examinees had chronic inflammation of varying degree.

Adolescent↗
PubMed2003

Intracerebroventricular administration of leptin-induced apoptosis in the rat small intestinal mucosa.

The localization of leptin and leptin receptors in the stomach and small intestine has been reported. Their function is still unknown, although leptin is a hormone that regulates appetite and fat-related metabolism. The small intestine is one of the important organs for regulating metabolism. The purpose of the present study was to investigate whether leptin regulates apoptosis in the small intestinal mucosa. Intestinal apoptosis was evaluated by percent fragmented DNA, electrophoresis, TUNEL staining, and western blotting analysis of caspase-3. Mucosal apoptosis in the rat jejunum and ileum was evaluated at 0, 3, 6, 12, and 24 hrs after injection. Rats were tested after ad libitum feeding and 24-hr fasting to exclude the anorectic effect of leptin. Leptin was injected intraperitoneally (ip) at a dose of 200 microg/rat and infused into the rat third cerebroventricle (icv) at a dose of 8 microg/rat. Leptin at a dose of 8 microg/rat significantly induced intestinal apoptosis in the small intestine at 3 and 6 hrs after icv administration in both ad libitum feeding and 24-hr fasted rats. This increase in apoptosis was not attenuated by vagotomy. Intestinal apoptosis increased 12 and 24 hrs after ip injection of leptin at a dose of 200 microg/rat. The peak of the increase in apoptosis in icv rats appeared earlier than that in ip rats. Leptin induced jejunal and ileal mucosal apoptosis in the rat, indicating that leptin might control intestinal function through the regulation of intestinal apoptosis.

Animals↗
PubMed1987

Metabolism of zearalenone by sow intestinal mucosa in vitro.

Homogenized intestinal mucosa samples from sows were incubated with zearalenone in the presence of NADPH or UDPGA. In addition, UDPglucuronosyltransferase activity in the microsomal fraction of mucosa was determined using 1-naphthol as substrate. In the presence of NADPH, zearalenone was reduced to both alpha- and beta-zearalenol (0.37 +/- 0.18 and 0.29 +/- 0.11 nmol/mg protein/hr in the duodenum and jejunum, respectively). The beta-isomer was the predominant metabolite. Glucuronide conjugation of zearalenone was very high compared with the level of reduction occurring (11.3 +/- 6.1 and 9.4 +/- 5.8 nmol conjugated/mg protein/hr in the duodenum and jejunum, respectively). There was no correlation between the rates of glucuronide conjugation of zearalenone and 1-naphthol, indicating that they depend upon two different isoenzymes of UDPglucuronosyltransferase.

Animals↗