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PubMedDate not supplied

[Changes in the rat intestinal mucosa in hypervitaminosis A].

Administration of excess vitamin A to the growing male rats (50 000 IU of oily solution of retinol palmitate a day for 8 days) provoked a tendency toward a decrease in the number of goblet cells (of both absolute and relative number calculated per 500 cells of the epithelium) in the crypts and villi of the small intestinal mucosa, with this tendency being more marked in the inferior part of the intestine. At the same time administration of vitamin A excess increased the intensity of staining with alcyane blue of the secretion of the goblet cells, particularly on the apeces of the villi, which indicates the increased content of acid glycoconjugates in these cells. hypervitaminosis A was also accompanied by the intensification of infiltration with lymphocytes of the small intestinal epithelium and led to an increase in the number of plasma cells in the natural membrane of the villi. It is inferred that vitamin A excess produces an impairment in the program of enterocyte differentiation, characterized by both acceleration (an increase in the content of acid glycoconjugates in the goblet cells) and retardation (a decrease in the number of the goblet cells) of its individual aspects. At the same time hypervitaminosis A produces an adaptive-compensatory reaction on the part of the small intestinal mucosa, manifesting in activation of its infiltration with immunocompetent cells.

Animals↗
PubMed2002

[The protective effects of small dose of dopamine on the intestinal mucosa of scalded rats in shock stage].

OBJECTIVE: To investigate the protective effects of small dose of dopamine on the intestinal mucosa of scalded rats in shock stage. METHODS: Wistar rats inflicted by 30% TBSA of III degree scalding were employed as the model. The rats were pre-placed with cardiac catheter before and were resuscitated intravenously after injury. The scalded rats were treated by routine (control) and small dose of dopamine (3 micro g.kg(-1).min(-1)), respectively. The changes of rat serum levels of diamine oxidase (DAO), malondialdehyde (MDA) and lactic acid (LA) were observed after treatment. And the pathomorphological changes of the intestine were scored. RESULTS: The general condition of the rats with dopamine treatment in shock stage was better than that in control group. The rat serum levels of MDA, LA and DAO decreased obviously, especially during 3 to 12 postburn hours (PBHs) after treatment by small dose of dopamine. The pathomorphological scoring of ileum in dopamine treating group was better than that in control. CONCLUSION: The intestinal mucosa of severely scalded rats in shock stage could be well protected by small dose of dopamine.

Animals↗
PubMedDate not supplied

The longitudinal distribution of cadmium, zinc, copper, iron, and metallothionein in the small-intestinal mucosa of rats after administration of cadmium chloride.

Different routes of Cd intake may influence the intestinal distribution of Cd, metallothionein (MT), and trace metals differently. Therefore, we compared the effects of parenteral and enteral administration of Cd on the distribution of trace metals and MT along the small intestine. In a first experiment three groups of rats were employed: a control, one receiving CdCl2 within the drinking water, and another receiving sc injections of CdCl2. In a second experiment, rats were fed three different diets with either 0, 0.3, or 1 mmol CdCl2/kg for one and two weeks to study the time- and dose-dependent effects of orally administered Cd. Metal concentrations (Cd, Zn, Cu, Fe) were measured by atomic emission spectrometry and MT was determined by radioimmunoassay. Intestinal MT levels did not show proximodistal gradients in controls or after sc administration of Cd, but orally administered Cd increased mucosal MT levels longitudinally from the duodenum to the ileum. Cd levels paralleled those of MT. Compared with the metal concentrations in the controls, sc administration of Cd did not change intestinal Zn, Cu, and Fe levels. Oral administration of Cd, however, increased Cu and decreased Fe levels in the intestinal mucosa significantly. The second experiment revealed that only high dietary concentrations of Cd increase intestinal Cd and MT levels longitudinally toward the distal parts, whereas at lower dietary concentration the longitudinal distribution was reversed. This shows that different routes and doses of Cd intake lead to a different trace metal and MT distribution and emphasizes the role of dietary Cd in the local induction of small-intestinal MT.

Administration, Oral↗
PubMed1993

Alkaline lipase in rat intestinal mucosa: physiological parameters.

The present studies describe an alkaline active lipase in the rat intestinal mucosa. Alkaline lipase activity was determined using a glyceryl tri[14C]oleate emulsion at pH 8.0. Subcellular fractions were prepared from mucosal homogenates by differential centrifugation. Cells from villus to crypt were sequentially released using citrate and EDTA buffer. The enzyme was found to be most active in the proximal quarter of the intestine and in villus tips. Most of the activity was found in the cytosolic fraction. Bile salts stimulated the enzyme activity threefold. The presence of both Ca2+ and taurocholate was essential for optimal activity. Mucosal activity was greatly reduced on intraduodenal glyceryl trioleate infusion. Activity was restored when phosphatidylcholine was added to the glyceryl trioleate infusion. The fact that mucosal lipase has its greatest activity in the villus tips of the proximal intestine and in cytosol suggests that it may play an important role in mucosal glyceryltrioleate metabolism.

Alkalies↗
PubMed1997

Inhibition by aminosalicylates of lipid peroxidation in large intestinal mucosa after mesenteric ischemia/reperfusion in the rat.

To clarify the mode of action of aminosalicylates, which are generally used as therapeutic agents for ulcerative colitis, we investigated the effect of some of the aminosalicylates on lipid peroxidation in the large intestinal mucosa after mesenteric ischemia/reperfusion in the rat. Lipid peroxidation was assessed by measuring the level of thiobarbituric-acid-reactive substances. It was found that aminosalicylates dose-dependently inhibited the elevation of the level of thiobarbituric-acid-reactive substances in the large intestinal mucosa after ischemia/reperfusion. This effect may partly contribute to the therapeutic actions of aminosalicylates in ulcerative colitis.

Aminosalicylic Acids↗
PubMedDate not supplied

Platelet-activating factor acetylhydrolase activity in intestinal mucosa and plasma of patients with Crohn's disease.

The activity of platelet-activating factor (PAF) acetylhydrolase in biopsy specimens of intestinal mucosa was compared in patients with Crohn's disease (n = 11) and controls (n = 6). In addition, PAF acetylhydrolase activity was determined in the plasma of Crohn patients (n = 30) and healthy subjects (n = 35). The activity of PAF acetylhydrolase in mucosal samples from the distal ileum was significantly lower in Crohn patients than in control patients (p < 0.02), whereas there was no difference in PAF acetylhydrolase activity of colonic or jejunal samples between Crohn patients and controls. The PAF acetylhydrolase activity in the plasma of Crohn patients was significantly decreased as compared to healthy subjects. Crohn patients with high disease activity (symptomatic index > 150) had a significantly lower PAF acetylhydrolase activity in plasma, as compared to patients in clinical remission (symptomatic index < 150; p < 0.02), and as compared to healthy subjects (p < 0.001). PAF acetylhydrolase activity in plasma increased within 4 months after bowel resection (p < 0.05). These findings indicate that the PAF acetylhydrolase activity is decreased in the ileal mucosa of patients with Crohn's disease and that PAF acetylhydrolase activity in plasma is inversely related to disease activity in Crohn's disease. The possibility that PAF acetylhydrolase is one factor of importance for protecting the intestinal mucosa against PAF-mediated inflammation is inferred.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1986

Distribution of glycosphingolipids of monkey small and large intestinal mucosa.

The ganglioside and neutral glycosphingolipid composition of adult monkey small and large intestinal mucosa were characterized and compared. GM3, GM2 and GD1A were found to be the principal gangliosides in each of these tissues. Dihexosylceramide was the major neutral glycosphingolipid of both organs. The total content of gangliosides and neutral glycolipids/ceramide, however, was ca. four-fold and two-fold higher, respectively, in small intestinal than colonic mucosa. While all glycosphingolipids examined contained hydroxy and nonhydroxy fatty acids, the former fatty acids accounted for 60-90% of the total fatty acids in both organs. Sphingosine was the predominant long chain base of ceramide, mono-, di-, tri- and tetrahexosylceramide, whereas phytosphingosine was the major base of GM3 in both tissues. The results of these studies demonstrate that while many similarities of monkey small and large intestinal glycosphingolipids exist, qualitative and quantitative differences are present along the length of the monkey gut. These differences may be at least partially responsible for certain of the well-recognized variations in normal physiological and pathological processes that occur in these organs.

Animals↗
PubMed1982

Flat small intestinal mucosa and autoantibodies against the gut epithelium.

A male infant, aged 1 year 3 months, was admitted to the hospital with protracted diarrhoea, vomiting, and weight loss. The diarrhoea and vomiting coincided with an outbreak of acute diarrhoea and vomiting affecting other family members. Biopsy showed a flat small intestinal mucosa which did not respond to a diet free of gluten, cow's milk, and eggs, or during 8 weeks of intravenous alimentation. Steroids were given, and courses of nalcrom and later cimetidine, but these did not produce any significant improvement. A rare IgG autoantibody specific for gut epithelium was found, which, when present, was associated with a cytological abnormality of crypt enteroblasts. The autoantibody disappeared after treatment with cyclophosphamide, and the cytological abnormality subsequently diminished. However, the mucosa remained severely abnormal and has been so for 23 months. It is possible that an autoimmune reaction against the patient's small intestinal mucosa has led to persistence of the enteropathy.

Animals↗
PubMed1977

Kinetics of preneoplastic epithelia of the the intestinal mucosa induced in Buffalo rats by oral administration of N,N'-2,7-fluorenylenebisacetamide.

A diet containing 0.025% of N,N'-2,7-fluorenylenebisacetamide (2,7-FAA) was administered orally to 18 Buffalo rats for 3 months and to 21 rats for 5 months which corresponded to non-neoplastic stage and preneoplastic stage of carcinogenesis of the intestinal mucosa, respectively. The mitotic index, labeling index, and generation time of the epithelia of the intestinal mucosa of these stages were examined by autoradiography. 1) The mitotic index and labeling index decreased in the rats fed 2,7-FAA for 3 months than those of the non-treated controls. 2) Decrease of both indices was also observed in the rats fed 2,7-FAA for 5 months, except for the proximal part of the colon. 3) Around 1-hr prolongation of the generation time was observed in the epithelia of rats fed 2,7-FAA for 3 months compared with the non-treated control rats, and this was mainly due to the prolongation of the duration of the G1 phase. 4) Two- or three-hour prolongation of the generation time was observed in the epithelia of rats fed 2,7-FAA for 5 months compared with the non-treated control rats, and this was mainly due to the prolongation of the duration of the S phase.

2-Acetylaminofluorene↗
PubMed1999

Cloning, sequencing and further characterization of acylpeptide hydrolase from porcine intestinal mucosa.

Acylpeptide hydrolase was purified to homogeneity from porcine intestinal mucosa using a seven-step procedure including ammonium sulfate precipitation, gel filtration as well as anion exchange and affinity chromatography. The specific activity of the enzyme reached 105000 nmol/mg protein per min and the purification was as high as 5500-fold. This tetrameric enzyme is composed of four apparently identical subunits, the molecular mass of which was estimated to be 75 kDa, based on the results of amino acid analysis and gel electrophoresis performed under denaturing conditions. It is likely that the NH(2)-terminal residue may be acetylated, while serine was found to be the COOH-terminal residue. The hydrolytic activity of the enzyme toward N-acetyl-L-alanine p-nitroanilide at the optimum pH value was increased twofold in the presence of the chloride anion. The K(m) value calculated from the kinetics of the hydrolysis of acetylalanyl peptides was found to be 0.7+/-0.1 mM, whereas the V(max) values decreased from 200 to 50 nmol/min per microgram of enzyme, depending on the peptidic chain lengths. The V(max) value of the synthetic substrate (250 nmol/min per microgram of enzyme) was 25-500% higher than those of the acetylalanyl peptides, depending on the peptide chain length, although the enzyme affinity was slightly lower (1.8 mM as compared with 0.7 mM). In line with data on other animal species and on various tissues, the enzyme seemed likely to be a serine protease, since it was readily inhibited by diisopropyl fluorophosphate and diethyl pyrocarbonate. A 2377-nucleotide long cDNA coding for the enzyme was isolated from pig small intestine. The deduced amino acid sequence consisted of 731 residues and showed a single different amino acid with that of the porcine liver APH, except the N-terminal amino acid which is still probably lacking.

Amino Acid Sequence↗
PubMed1982

[Ultrastructure of the small intestine mucosa of gnotobiotic rats with a Vibrio cholerae carrier state].

Ultrastructure of the small intestinal mucosa of gnotobiotic rats, carriers of Vibrio eltor or V. Cholerae was studied. The cytoplasm of enterocytes manifested an increased number of lysosome-like structures and hypertrophy of the Golgi complex. Unlike V. eltor, V. cholerae induced more intensive extrusion of enterocytes and appreciable infiltration of the epithelial layer with lymphocytes. It is concluded that chronic vibrio-carrier state in gnotobiotic rats is not associated with pathological alterations.

Animals↗
PubMed1975

Mechanisms of lipid loss from the small intestinal mucosa.

Many water-soluble compounds have been shown to pass from the small intestinal mucosa into the lumen. In this work, the loss of lipids from the mucosa was investigated by perfusion experiments in rats, using 0-15M NaCl or buffer solutions over range of pH, with or without the addition of 5-7 or 11-4mM taurocholic acid. Perfusates were extracted for the estimation of individual lipids and for DNA, which is a measure of cell loss. The results suggest that free fatty acids reach the lumen by diffusion and that their solubility in the luminal fluid is a factor determining their rate of loss. Triglycerides, cholesterol, phosphatidyl ethanolamine, and phosphatidly choline are present onlyas the result of desquamation of mucosal cells.

Animals↗
PubMed1994

Cytokine gene expression in HIV-infected intestinal mucosa.

OBJECTIVE: Cytokine dysregulation has been implicated in AIDS pathogenesis and the gastrointestinal tract, containing approximately 40% of the body's lymphoid tissue, is likely to act both as a reservoir of viral infection and a site for immune dysregulation. In this study evidence of cytokine dysregulation in intestinal mucosa has been sought using the reverse transcriptase polymerase chain reaction (RT-PCR) to amplify cytokine mRNA. METHODS: RT-PCR was performed on intestinal biopsies obtained from 50 HIV-infected patients and 31 controls. Tissue was obtained at diagnostic endoscopy and total RNA extracted using an RNAzol technique. Following RT, cDNA was amplified using primers specific for beta-actin, interleukin (IL)-1 beta, tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, IL-2, IL-4, IL-10 and IL-13. RESULTS: There was a significant increase in the expression of the proinflammatory cytokines IL-1 beta and IFN-gamma in the HIV-infected compared with the control small intestinal samples (P < 0.01). IL-10 was significantly reduced in the respective groups' large intestine (P < 0.02). The expression of IL-2 was also reduced in both the small and large intestinal HIV samples although this was not significant. IL-13 mRNA was only detected in one control patient. CONCLUSIONS: Dysregulation of cytokine gene expression occurs in the intestinal mucosa of patients with HIV infection and is characterized by increased expression of proinflammatory cytokine mRNA. Further studies are needed to localize the cellular origin of such dysregulation and to quantify the degree of abnormality.

Base Sequence↗
PubMed2006

A new organotypic model to study cell interactions in the intestinal mucosa.

BACKGROUND: Recently, we demonstrated that freshly elutriated monocytes differentiate into macrophages with a phenotype similar to that of intestinal macrophages in a three-dimensional model of intestinal epithelial cells. Here we describe a more organotypic model to study cell interactions in the intestinal mucosa. METHODS: Primary intestinal fibroblasts and freshly elutriated blood monocytes (ratio 1:1) were embedded in collagen type I gels and cultured for 5 days. At day 5, intestinal epithelial cells (HT-29) were seeded on top of the collagen gels. After another 7 days collagen gels were harvested and fixed for immunohistochemical analysis. Cryosections of the aggregates were prepared and staining for monocyte/macrophage markers and basement membrane compounds was performed. Cell interactions inside the aggregates were examined by electron microscopy. RESULTS: Intestinal fibroblasts contracted the collagen gels which formed stable three-dimensional aggregates within the first 5 days of culture. Intestinal epithelial cells formed a monolayer on top of the gels about 3 days after seeding. Intestinal fibroblasts were distributed randomly over the aggregate. Monocytes inside aggregates were localized in the vicinity to epithelial cells by positive staining for CD68. Typical monocyte/macrophage specific markers such as CD14, CD16, CD11b, CD11c and the co-stimulatory molecules CD80 and CD86 were down-regulated or not detectable on these cells after co-culture in three-dimensional aggregates. Omission of epithelial cells from the model was followed by impaired differentiation of intestinal macrophages. CONCLUSION: In the three-dimensional organotypic cell culture model monocytes differentiate into intestinal-like macrophages when co-cultured with control intestinal fibroblasts and intestinal epithelial cells. Intestinal epithelial cells may be necessary for differentiation of intestinal macrophages.

Cell Communication↗
PubMed1985

Scanning electron microscopy of Ancylostoma ceylanicum and its site of attachment to the small intestinal mucosa of the dog.

The relationship between the hookworm Ancylostoma ceylanicum and the host intestinal mucosa in situ has been examined by using an in vivo fixation technique and scanning electron microscopy. Heads of the adult worms were buried deeply in the mucosa of the dog's small bowel. At some sites of attachment there was severe atrophy and ulceration of the immediately surrounding villi. Superficial deposits of fibrillar material with many enmeshed erythrocytes were associated with these attachment sites. When adult worms became removed after fixation, large numbers of erythrocytes could be seen at the base of the ulcers. Examination of the morphological details of adult A. ceylanicum revealed the characteristic mouthparts of large outer ventral teeth and smaller inner teeth. The distance between adjacent transverse cuticular striations was measured as 5.2 microns. The wide separation of the externolateral ray from the closely related mediolateral and posterolateral rays was illustrated together with the functi characteristic mouthparts of large outer ventral teeth and smaller inner teeth. The distance between adjacent transverse cuticular striations was measured as 5.2 microns. The wide separation of the externolateral ray from the closely related mediolateral and posterolateral rays was illustrated together with the functi characteristic mouthparts of large outer ventral teeth and smaller inner teeth. The distance between adjacent transverse cuticular striations was measured as 5.2 microns. The wide separation of the externolateral ray from the closely related mediolateral and posterolateral rays was illustrated together with the functional relationship of male and female copulating worms.

Ancylostoma↗
PubMed1980

[Interaction between lactobacilli and the intestinal mucosa].

The study of the distribution of lactobacilli in the lumen and on the mucosa of the intestine of CBA mice, as well as the interaction of lactobacilli with the mucosa under normal conditions and in experimental postradiation dysbacteriosis, showed that under normal conditions lactobacilli could be found practically in all portions of the intestine of the mice both in the lumen and on the mucosa. Lactobacilli were closely associated with the mucosa, and this association was not affected by the treatment of the mucosa with trypsin and detergents. In postradiation dysbacteriosis the association of lactobacilli with the mucosa became weaker; as a result, the number of bacteria associated with the mucosa decreased 10 times. Exogenic streptomycin-resistant lactic acid bacteria, subjected to multiple passages through the organism of the animals, could take on the intestinal mucosa.

Animals↗