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 37 records · Page 2Linked to original sources
PubMed1976

[Comparison of different morphometric methods to estimate the surface of the rat intestinal mucosa. Their relationship to intestinal function (author's transl)].

In contrast to the human small intestine with predominantly fingerlike villi, trapezoid forms are encountered in the small bowel of the rat. For this reason, it is doubtful whether it is sufficient to measure the villus height alone as a representative parameter for the assessment of the villus surface. In this study, the method developed by Clarke is employed to calculate the villus surface per unit area of intestine. The data obtained by this method are compared with those estimated planimetrically. Correlations were then established between the absorptive capacity and enzymatic activity of the intestinal mucosa on the one hand, and the villus height or the villus area obtained by each method on the other hand. Under our experimental conditions--a hyperregenerative transformation of the intestinal mucosa caused by chronic exposure to glucagon--the results indicate that the calculated villus surface per unit area of small intestine correlates better than the villus height with the functional parameters of the intestinal mucosa.

Animals↗
PubMed1987

Intestinal epithelial cells preferentially attach to a biomatrix derived from human intestinal mucosa.

Primary intestinal epithelial cells have a very short lifespan in vitro when cultured free of mucosal elements. Support of the basal plasma membrane by a more natural substrate may thus enhance the initiation of primary cell cultures. A cell free biomatrix consisting of native interstitial collagens, basement membrane fragments and microfibrils was extracted from the lamina propria of human intestinal mucosa. Immunofluorescence revealed the presence of collagens type III, IV, and VI and procollagens type I and III as well as fibronectin, laminin and undulin. Primary crypt cells of suckling mice displayed a significantly increased affinity to pepsin and collagenase solubilised intestinal biomatrix when compared with plastic and fibronectin. Colonies of primary crypt cells survived for up to four days and longer on pepsin solubilised biomatrix but only for 48 hours on fibronectin. The intestinal biomatrix preparation has proved to be a useful substrate for the initiation and prolongation of primary intestinal cell cultures.

Adult↗
PubMed1976

Coenzyme-A-dependent esterification of cholesterol in rat intestinal mucosa.

Rat intestinal mucosa contains an enzyme which catalyses the esterification of cholesterol. The enzyme is CoA-dependent and probably an acyl-CoA: cholesterol acyltransferase (ACAT) (E.C.2.3.1.26). Maximal activity in vitro is obtained when long chain acylcarnitines, CoA and carnitine palmityltransferase are used as an acyl-CoA generating system. The enzyme is localized in the microsomal fraction, has a pH optimum between 6.4-7.2, and oleate is the preferred acyl group. The activity of the enzyme is highest in the proximal jejunum, and has a capacity that can account for all cholesteryl esters found in intestinal rat lymph.

Acetyl Coenzyme A↗
PubMed1983

RNA synthesis by villus and crypt cell nuclei of rat intestinal mucosa.

Rat intestinal mucosa was separated by eversion and vibration to provide a sequence of fractions from predominantly villus cells to predominantly crypt cells. The proportions of these cell types in each fraction were computed from the concentrations of alkaline phosphatase (villus cells) and thymidine kinase (crypt cells) in each population. The isolated mucosal fractions varied from about 90% villus cells to 90% crypt cells. Following injection of the rats with [3H]thymidine, the nuclei were isolated from each mucosal cell fraction and the amount of radioactivity incorporated into DNA was measured as an index of crypt cell abundance. The isolated nuclei were also incubated with ribonucleoside triphosphates and the amount of RNA synthesized was measured. Nuclei labeled with [3H]thymidine were found only in fractions rich in crypt cells, whereas capacity for RNA synthesis remained very active in mucosal fractions consisting predominantly of villus cells. It is concluded that non-dividing villus cells continue to make RNA.

Alkaline Phosphatase↗
PubMed1978

Differentiation and aging of the rat intestinal mucosa. II. Morphological, enzyme histochemical and disc electrophoretic aspects of the aging of the small intestinal mucosa.

At different times of day (08.00, 12.00, 16.00 and 24.00) the small intestinal mucosa of four month (adult) and 30 month (senile) old rats was examined histologically, by scanning electron microscopy, autoradiography, enzyme histochemistry and disc electrophoresis. In senile rats a villous atrophy is found histologically and an irregular architecture is found in scanning electron microscopy. The changes are essentially restricted to the proximal small intestine. The enterocytes of adult and senile rats show an identical enzyme histochemical picture. In the proximal small intestine of adult and senile rats, synchronous statistically significant fluctuations of the activity of alkaline and acid phosphatase were revealed in the disc electropherograms. Likewise statistically significant are the at all times of day low enzyme activities in the intestinal mucosa of senile rats as compared to the findings in adult rats. The fall in activity of alkaline and acid phosphatase in old rats is attributed to the numerical reduction of the enterocytes which is caused by the age atrophy of the intestinal mucosa. These findings are discussed in connection with results of our own studies of proliferation kinetics and those of other authors.

Acid Phosphatase↗
PubMed2001

Apoptosis induced by ischemia-reperfusion and fasting in gastric mucosa compared to small intestinal mucosa in rats.

The effect of ischemia-reperfusion and 48-hr fasting on apoptosis was characterized in rat gastric mucosa and compared to small intestinal mucosa. Under halothane anesthesia, the celiac artery or superior mesenteric artery in the rat was occluded for 60 min followed by reperfusion. Occlusion of the celiac artery reduced blood flow in the stomach and occlusion of the mesenteric artery reduced blood flow in the small intestine. Additional rats were fasted for 48 hr to evaluate the effect of fasting on mucosal apoptosis. The ratios of fragmented DNA to total DNA, electrophoresis, and immunohistochemical staining were examined after ischemia-reperfusion or fasting. Apoptosis was not induced significantly in the gastric mucosa after ischemia-reperfusion, although it increased dramatically in the intestinal mucosa after ischemia-reperfusion. Further, after 48 fasting, apoptosis was induced in the small intestine, but not in the stomach. These results indicate that rat gastric mucosa is not as sensitive as small intestinal mucosa to ischemia-reperfusion or fasting-induced apoptosis.

Animals↗
PubMed1974

Vasoactive intestinal peptide stimulation of adenylate cyclase and active electrolyte secretion in intestinal mucosa.

Vasoactive intestinal peptide (VIP), originally isolated from hog small intestinal mucosa, has been shown to cause small intestinal secretion. More recently, this peptide has been identified in the plasma and tumors of patients with the so-called "pancreatic cholera" syndrome. In order to explore the possible role of VIP in the pathogenesis of this syndrome, we examined the effects of this peptide and other hormones on the cyclic AMP levels, adenylate cyclase activity, and ion transport in in vitro preparations of ileal mucosa. In rabbit ileal mucosa, VIP (20 mug/ml) caused a prompt fivefold increase in cyclic AMP level, whereas nine other hormones, which have been postulated to cause intestinal secretion, failed to exert such an effect. Pentagastrin and glucagon also failed to increase cyclic AMP levels in canine ileal mucosa. An increase in mucosal cyclic AMP levels was observed at a VIP concentration of 0.1 mug/ml and appeared to be nearly maximal at 2.0 mug/ml. VIP (100 mug/ml) stimulated adenylate cyclase activity in a membrane preparation from rabbit ileal mucosa. Secretin (6.0 x 10(-5) M) failed to do so. When added to the serosal side of isolated rabbit ileal mucosa clamped in an Ussing chamber, VIP (2 mug/ml) increased short-circuit current (SCC) and caused net secretion of both Cl and Na. Net Cl secretion exceeded net Na secretion. These effects of VIP on mucosal cyclic AMP metabolism and ion transport are similar to those observed with cholera enterotoxin and certain prostaglandins. VIP was also tested with normal human ileal mucosa. At a concentration of 2 mug/ml it caused a fivefold increase in cyclic AMP level and an increase in SCC of the same magnitude as that caused by 5 mM theophylline. Addition of a second 2-mug/ml dose of VIP and addition of theophylline after VIP produced no further change in SCC. We conclude the VIP stimulates adenylate cyclase and active ion secretion in both rabbit and human ileal mucosa. This may be related to the pathogenesis of diarrhea in patients with the pancreatic cholera syndrome.

Adenylyl Cyclases↗
PubMed1976

[Adaptive changes in intestinal mucosa of the small intestine as a result of intraluminal stress].

Under physiological conditions, the intestinal mucosa is the site of a delicate balance between cell proliferation in the crypt region and cell desquamation at the villus tips. This balance can be deranged by a number of endogenous or exogenous factors, oneof which is the intraluminal contents. This review discusses the effects of different modifications of the luminal milieu on the structure and function of the mucosa. Following intestinal resection or loop transposition, the contents reaching the remnant or the transposed loop differ markedly from those with which they come into contact under normal conditions. Hyperplasia without zonal transformation then develops in the experimental loop. The villi do not become wider, and changes in the strucutre of the epithelium are not observed. There are conflicting resutls in the literature concerning the enzyme activities in the individual enterocytes resulting from this hyperplasia. However, the epithelium its functionally immature, since transport capacities measured in vitro are reduced. On the other hand, the hyperplasia of the mucosa is such that absorptive capacities in vivo, when expressed in terms of intestinal length, are larger than normal. When the intestine is subjected to prolonged infusion of lactic acid, the enterocytes are damaged and increased exfoliation results. A similar result is obtained in the blind-loop syndrome, where the accumulation of bile acids and bacteria provides the stress responsible for the destruction of the enterocytes, and in non-tropical spure, where the epithelium is attacked by noxious peptides in the diet. The first consequence of the accelerated desquamation is epithelial hyperplasia without zonal transformation, though the enterocytes are damaged - in contrast to those of the resected intestine - and apparently possess reduced enzyme activities. If the application of the stress is continued, a stage is reached in which the cell proliferation does not suffice to counteract the cell loss at the villus tips. Then a zonal transformation occurs whereby, despite the lengthened crypts, the villi become shorter and wider until, in extreme cases, the mucosa is completely devoid of villi. The transport capacity in vitro and in vivo - even when expressed in terms of unit-length is reduced, and good correlations exist between the reduction in function and the diminution in surface area of the intestine. In a self-emptying blind loop, the intestine is devoid of all contact with nutritional material. Under these circumstances, hypoplasia of the mucosa develops in which the enterocytes appear unchanged, though in extreme cases they may possess reduced enzyme levels, and the absorption capacity in vivo is consequently reduced.

Adaptation, Physiological↗
PubMed1985

Somatostatin binding sites in cytosolic fraction of rabbit intestinal mucosa: distribution throughout the intestinal tract.

Specific binding sites for somatostatin have been identified in cytosolic fraction of both small and large intestinal mucosa. The stoichiometric data suggested the presence of two classes of binding sites in each part of the intestine. The binding capacity varied depending on the segment considered (rectum greater than duodenum = jejunum greater than ileum, caecum and colon). However, the affinities of the binding sites were similar throughout the whole intestinal mucosa, with the exception of rectum which showed higher Kd values. The binding sites were shown to be highly specific for somatostatin since neuropeptides such as vasoactive intestinal peptide, neurotensin, substance P and Leu-enkephalin did not show any effect upon somatostatin binding.

Animals↗
PubMed1988

Intestinal mucosa diamine oxidase activity reflects intestinal involvement in Crohn's disease.

The activity of diamine oxidase (DAO), an enzyme found in the apical villous cells of the small intestine mucosa, should reflect the status of the intestinal mucosa. Our purpose was to determine whether DAO activity in the intestinal mucosa is diminished in patients with Crohn's disease and correlates with the severity of histological changes. Mucosal DAO activity was determined in 42 tissue specimens from patients with Crohn's enteritis (n = 15), Crohn's colitis (n = 9), and ulcerative colitis (n = 11), and from patients with no intestinal disease (n = 7). DAO activity was estimated by the metabolism of [14C]putrescine. Histologic changes were graded on a scale of 0-4. Normal histology was graded as zero, mild edema, and inflammation in the lamina propria as one, crypt abscess formation and inflammation as two, more severe inflammation plus or minus granulomata as three, and most severe inflammation with active ulceration as four. Tissue DAO activity was significantly less in patients with ileitis (4.8 +/- 3.6) compared with those with Crohn's colitis (15.0 +/- 11.6), ulcerative colitis (16.8 +/- 19.7), and normal intestine (17.6 +/- 14.3 U/mg protein/h, p less than 0.05). Intestinal DAO activity showed a positive correlation with the histologic scores. Recurrence of Crohn's disease developed postoperatively in two patients with low tissue DAO activity (1.4 and 2.9 U/mg protein/h). Intestinal DAO activity is diminished in patients with Crohn's ileitis and correlates with the severity of histologic changes. Tissue DAO activity might prove useful in predicting the risk of recurrence or anastomotic complications after resection for Crohn's disease.

Adult↗
PubMed2006

Breakdown of intestinal mucosa via accelerated apoptosis increases intestinal permeability in experimental severe acute pancreatitis.

BACKGROUND: Bacterial translocation plays an important role for infectious complications in severe acute pancreatitis (SAP). Breakdown of intestinal mucosal integrity may increase intestinal permeability and may be implicated in bacterial translocation. It is suggested that increase in intestinal permeability is correlated with the changes of tight junction and/or apoptosis in intestinal epithelial cells. The aim of this study was to investigate the changes of intestinal mucosa and its permeability in SAP. METHODS: SAP was induced by injection of 3% sodium deoxycholate into the biliopancreatic ducts in rats. Permeability of intestinal wall was assayed ex vivo by measuring the leaked amount of FITC-dextran from the ileum pouch. Alteration of tight junction proteins such as zonula occludens (ZO)-1 and Occludin was evaluated by Western blotting and immunofluorescence staining. Apoptotic change of intestinal mucosa was detected by TUNEL staining and DNA fragmentation ELISA. In vitro, apoptosis-inducing effect of pancreatitis-associated ascitic fluid (PAAF) was examined using T84 cells. Integrity of monolayer cells was assessed by transepithelial electric resistance (TEER). RESULTS: Permeability of ileum was significantly increased 6 h after induction of SAP. Blood endotoxin level was significantly elevated and bacterial translocation occurred 18 h after induction of SAP. Six hours after induction of SAP, expressions of ZO-1 and Occludin were not altered, but apoptosis of ileum mucosa was significantly accelerated. Addition of PAAF to T84 cells did not affect expressions of ZO-1 or Occludin, but significantly increased the apoptosis and significantly decreased TEER. CONCLUSIONS: These results suggest that breakdown of intestinal mucosa via accelerated apoptosis may increase in intestinal permeability in SAP and that PAAF contains factor(s) that accelerates the apoptosis of intestinal epithelial cells.

Animals↗