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PubMed1999

Differing patterns of transforming growth factor-beta expression in normal intestinal mucosa and in active celiac disease.

BACKGROUND: Growth-inhibitory autocrine polypeptides such as transforming growth factor (TGF)-beta may play a role in the control of normal epithelial cell proliferation and differentiation. In addition, TGF-beta has a central role in extracellular matrix homeostasis and regulates the immune response at the local level. In this study immunohistochemistry was used to examine the pattern of TGF-beta protein distribution and quantitative reverse transcription-polymerase chain reaction (RT-PCR) to determine levels of TGF-beta messenger RNA expression in normal intestinal mucosa and in the flat mucosa of children with celiac disease. METHODS: Small intestinal biopsies were performed in children with active celiac disease and in histologically normal control subjects. Frozen sections were single stained using an anti-TGF-beta monoclonal antibody and were double stained for TGF-beta and T cell, macrophages, and the activation marker CD25. Total RNA was extracted from frozen specimens and competitive quantitative RT-PCR performed for TGF-beta mRNA using internal synthetic standard RNA. RESULTS: In normal intestinal mucosa, by immunohistochemistry, TGF-beta expression was most prominent in the villous tip epithelium, whereas in the lamina propria, weak immunoreactivity was present. The celiac mucosa showed weak and patchy epithelial TGF-beta immunoreactivity. In contrast, an intense staining positivity was present in the lamina propria localized mostly in the subepithelial region where T cells, macrophages, and CD25+ cells were detected by double staining. By quantitative RT-PCR, levels of TGF-beta mRNA transcripts appeared to be increased in celiac intestinal mucosa compared with that in control subjects, although the difference did not reach statistical significance. CONCLUSIONS: These observations suggest that TGF-beta expression is associated with differentiated enterocyte function. In celiac disease the lower TGF-beta epithelial cell expression could be a consequence of the preponderance of a less differentiated epithelial cell phenotype also present in the surface epithelium. In contrast, the prominent TGF-beta positivity of the subepithelial lamina propria suggests an association with the local immune and inflammatory response, as well as a potential role of these peptides in mesenchymal-epithelial cell interaction.

Antigens, CD↗

PubMed1981

Effect of folate deficiency on microsomal drug metabolism and heme content in the intestinal mucosa of guinea pigs.

The relationship between folate deficiency, heme content, and microsomal drug metabolism in the intestinal mucosa of the guinea pig was examined. Weanling male guinea pigs were pair-fed a folate-deficient diet, and intestinal mucosal folate levels were measured. A significant decrease (75%) in these levels was observed at 3 weeks after diet initiation. A significant decrease (78%) in intestinal mucosal drug metabolism (7-ethoxycoumarin O-deethylase activity) and a significant decrease (46%) in intestinal mucosal heme content were also observed at this time. These findings indicate that folic acid deficiency in the guinea pig results in a marked reduction in heme content and microsomal drug metabolism of the intestinal mucosa.

Animals↗

PubMed2003

Histopathological study of rabbit intestinal mucosa infected with a hybrid strain of Shigella dysenteriae 1 carrying LPS biosynthesis genes of Salmonella enterica serovar typhimurium.

The rfb gene cluster and the rfc gene of Salmonella enterica were introduced earlier into an invasive Shigella dysenteriae 1 strain by triparental cross. Antiserum was raised in rabbit against lipopolysaccharide isolated from the hybrid strain. Both the hybrid and the invasive S. dysenteriae 1 strain were found to have a titer of 1:2560 while for S. enterica, it was 1:640. Ligated ileal loops were prepared in rabbit, which were inoculated with 10(8) CFU ml(-1) each of the hybrid strain, and invasive S. dysenteriae 1 strain used as positive control. Escherichia coli K12 was also used as a negative control. After 18 h, the fluid accumulation ratios were 0.2 and 1.6 for hybrid and invasive strains of S. dysenteriae 1, respectively. Rabbit intestinal mucosa infected with hybrid S. dysenteriae 1 strain showed the presence of intact villus tips and unruptured intestinal mucosa whereas total necrosis of intestinal mucosa and villi was observed in the S. dysenteriae 1-infected region.

Animals↗

PubMed1981

Purification and properties of an endodeoxyribonuclease from nuclei of bovine small intestinal mucosa.

An endodeoxyribonuclease has been purified from nuclei of bovine small intestinal mucosa to a homogeneous state by a procedure involving affinity chromatography on heparin-agarose. The endonuclease, which was found to be bound to chromatin, has a pH optimum of 5.4. It requires Mn2+ or Co2+ for activity and its maximum activity with Mg2+ is about 80% of that with Mn2+. Its activity is strongly inhibited by sulfhydryl-blocking agents, and by ethidium bromide. The enzyme does not attack RNA and is inhibited by it. Its isoelectric point is 8.5 +/- 0.1, and its molecular weight is 49,000 +/- 3,000, determined by sucrose gradient sedimentation and gel filtration on Sephadex G-100. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated that the enzyme is composed of two nonidentical subunits with molecular weights of 30,000 and 23,000. The enzyme catalyzes the endonucleolytic cleavage of circular duplex ColE1 DNA via single strand scissions from the initial stage of degradation. The average size of the limit products of native phage T7 or ColE1 DNA is about 2,000 to 1,500 base pairs, estimated by neutral sucrose gradient sedimentation or agarose gel electrophoresis. The enzyme degrades denatured DNA about 20 times faster than native DNA. The products contain 5'-phosphoryl and 3'-hydroxyl termini, and all four deoxymononucleotides are present in almost equal amounts at the 5'-termini.

Animals↗

PubMed1987

Purification and active site modification studies on glyoxalase I from monkey intestinal mucosa.

Glyoxalase I ((R)-S-lactoylglutathione methylglyoxal-lyase (isomerizing), EC 4.4.1.5) from monkey intestinal mucosa was purified to homogeneity. The purified enzyme had a molecular weight of 48,000, composed of two apparently identical subunits. Active-site modification was carried out on the purified enzyme in presence and absence of S-hexylglutathione, a reversible competitive inhibitor of glyoxalase I. Modification by tetranitromethane and N-acetylimidazole caused inactivation of the enzyme. Inactivation by N-acetylimidazole was reversible with hydroxylamine treatment, suggesting the importance of tyrosine residues for the activity of the enzyme. The enzyme was inactivated by 2-hydroxy-5-nitrobenzyl bromide, N-bromosuccinimide, 2,4,6-trinitrobenzenesulphonic acid, pyridoxal phosphate and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, indicating the importance of tryptophan, lysine and glutamic acid/aspartic acid residues for the activity of the enzyme. The enzyme was inactivated by diethyl pyrocarbonate and the activity was not restored by hydroxylamine treatment, suggesting that histidine residues may not be important for activity. Modification by N-ethylmaleimide and p-hydroxymercuribenzoate did not affect its activity, indicating that sulphydryl groups may not be important for activity. These studies indicated that the amino acids present in the active site of glyoxalase I from intestinal mucosa which may be important for activity are tyrosine, tryptophan, lysine and glutamic acid/aspartic acid residues.

Amino Acids, Dicarboxylic↗

PubMed2005

Light and scanning electron microscopy evaluation of the postnatal small intestinal mucosa development in pigs.

Modifications in the structure of gastrointestinal mucosa is often used to evaluate gut function for instance during the development or in response to particular food components. Scanning electron microscopy (SEM) gives a chance to observe the surface of the gut epithelium in three dimensions. However, this technique is seldom used due to technical difficulties. The present study attempted to investigate the intestinal mucosa structure changes in the postnatal pig using light and scanning electron microscopy technique. Experiments were carried out on sow reared piglets from birth until 38 days of age. Piglets were sacrificed at birth and at the 3(rd), 7(th), 21(st) and 38(th) day of life. The entire gastrointestinal tract was immediately harvested and the whole thickness tissue samples were taken from the duodenum, jejunum and ileum for optical and scanning electron microscopy. SEM analyses corroborated with histometry made by optical microscopy. Moreover, a number of shape modifications of the villi and its surface have been observed. The development changes in small intestine mucosa during the first 3 weeks were manifested in shape, size and density of villi. In conclusion, the structure of small intestinal mucosa undergoes profound structural changes. SEM gives a new dimension in the investigation of gut mucosa.

Animals↗

PubMed2000

Histaminergic effect on apoptosis of rat small intestinal mucosa after ischemia-reperfusion.

This study aimed to examine the relationship between a harmful effect of histamine and apoptosis following ischemia-reperfusion in the rat intestine. The superior mesenteric artery was occluded for 60 min followed by reperfusion for 60 min. Rats were infused with H1-receptor antagonist (chlorpheniramine maleate) or H2-receptor antagonist (cimetidine). Additional rats were pretreated with aminoguanidine (100 mg/kg). Percent apoptosis in the intestinal mucosa increased after reperfusion, but neither H1 nor H2 antagonists had any effect on apoptosis. Aminoguanidine pretreatment inhibited activity of diamine oxidase and increased the plasma histamine concentration. Aminoguanidine attenuated the increase in mucosal apoptosis following reperfusion. Apoptosis induced by an ischemic insult to the intestinal mucosa was not related to an undesirable effect of histamine. Attenuation of increased intestinal apoptosis might be due to increased plasma histamine level and/or other pharmacological action of aminoguanidine, including inhibition of inducible nitric oxide synthase.

Animals↗

PubMed2001

Characterization of a membrane-bound arginine-specific serine protease from rat intestinal mucosa.

Previously we isolated and characterized a membrane-bound, arginine-specific serine protease from pig intestinal mucosa [J. Biol. Chem. 269, 32985-32991 (1994)]. For further characterization of this type of enzyme, we cloned a cDNA from rat intestinal mucosa encoding the precursor of a similar protease. The partial amino acid sequences determined for the pig enzyme were found to be shared almost completely by the rat enzyme. The serine protease domain of the rat enzyme, heterologously expressed in Escherichia coli, specifically cleaved Arg (or Lys)-X bonds with a marked preference for Arg-Arg or Arg-Lys, similar to the pig enzyme. The mRNA for the rat enzyme was shown to be distributed mainly in intestine, and the enzyme was detected in the duodenal mucosa as a 70 kDa protein. Immunohistochemical analysis of the small intestinal tissue showed that the enzyme is localized mainly on brushborder membranes.

Amino Acid Sequence↗

PubMed1990

[Densitometric analysis of aminopeptidase M activity in small intestine mucosa in piglets experimentally infected with Isospora suis].

In gnotobiotical and conventional piglets infected a day post partum (DPP) with oocysts of the coccidium Isospora suis, densitometrical analysis of the activity of aminopeptidase M (EC.3.4.11.2; APM) was performed in the area of microvillous zone of the small intestine. Piglets were infected with different infection doses of oocysts (100,000 oocysts) in gnotobiotical piglets and 200,000 oocysts in conventional piglets). In infected gnotobiotical piglets, the APM activity was studied in the period from the 3rd to 11th day after infection (DAI) and in infected conventional piglets in the period of to the 2nd to 10th day after infection (DAI). Control piglets, in the group of the gnotobiotical animals at the age of 2 to 5 days in the group of the conventional animals at the age of 4 to 7 days, had different APM activity in the microvillous zone of the intestinal mucosa. It was stated that the microvillous zone of the intestinal mucosa gained higher values in control conventional piglets (+7.01 mean values of density). In infected gnotobiotical piglets the density fall of the reaction product of APM was demonstrated already on the third day with further marked reduction of APM density on the 4th day after infection in the whole small intestine with predominance of the persisting APM activity in ileum. Even despite the slight increase in the density of the reaction product of APM in the period from the 5th to 7th DAI (the highest increase in APM density on the 6th DAI), a further decrease of the activity was recorded again on the 8th and namely the 9th DAI in the whole small intestine (the lowest value of density was found in the rear jejunum), the ileum mucosa being affected, too. A slightly higher density of the reaction product of APM was found in the duodenum. On the 10th DAI the APM density started to change and on the 11th DAI in the duodenum and in the middle jejunum it even reached higher values in comparison with the control data. Some differences were proved in the infected conventional piglets in comparison with the development of the APM activity in the small intestine mucosa in the infected gnotobiotical piglets. On the 3rd and 4th DAI APM defect occurred in the whole small intestine, with APM density prevailing in the ileum mucosa (like in the group of infected gnotobiotical piglets). The second period of decrease in APM activity lasted for almost four days (6th to 9th DAI).(ABSTRACT TRUNCATED AT 400 WORDS)

Aminopeptidases↗

PubMed1989

Effect of methotrexate on the intestinal mucosa of PGE2-treated rats.

In the present study, we aimed to protect the intestinal mucosa from small bowel damage in methotrexate (MTX)-treated rats. The protective effect of prostaglandin E2 (PGE2) was investigated. Ileal integrity was evaluated making use of different biochemical parameters: content of sucrase and maltase activities, contents of DNA, proteins, AMPc, PGE2, putrescine (Put), spermine (Spm) and spermidine (Spd). Rats were orally administered 0.5 ml of NaCl solution (0.9%) containing or not containing 400 micrograms.ml-1 of PGE2 twice daily, during three or ten days. Half an hour after the 18th ingestion of PGE2, 0.5 ml of NaCl solution (0.9%) containing MTX (16 mg.ml-1) was injected intravenously. Rats were killed exactly 48 hours after this injection. MTX had no effect on the Put content, increased the AMPc content and decreased the contents of DNA, proteins, Spm, Spd, PGE2 and sucrase or maltase activity. PGE2 had no effect on the biochemical parameters we studied, except on the contents of DNA (10-day treatment) and of PGE2 (3- and 10-day treatment). When MTX was injected after PGE2 treatment, as compared with what was observed when MTX was used as reported above, we observed--an increase in spermine content after 3-day PGE2 treatment and- an increase in the contents of DNA, Spm, Spd and disaccharidase activity after 10-day PGE2 treatment. No other significant variation in the other biochemical parameters was recorded, whatever the duration of the PGE2 treatment. These results indicate that PGE2 could partially protect the intestinal mucosa against the biochemical effects of MTX. Other experimental conditions may need to be chosen in order to obtain a better cytoprotective effect of PGE.

Amine Oxidase (Copper-Containing)↗

PubMed2001

Tropheryma whippelii DNA is rare in the intestinal mucosa of patients without other evidence of Whipple disease.

BACKGROUND: Little is known about the pathogenesis of Whipple disease, the reservoirs of Tropheryma whippelii, and the proportion of persons harboring the bacterium without "classic" intestinal abnormalities. OBJECTIVE: To assess the presence of T. whippelii in patients undergoing upper endoscopy for a variety of indications. DESIGN: Prospective and routine diagnostic examination of patients. SETTING: Three academic medical centers in California; Minnesota; and Heidelberg, Germany. PATIENTS: 342 patients undergoing endoscopy for evaluation of dyspepsia or possible peptic ulcer (group A, 173 patients), malabsorption (group B, 37 patients), or clinical suspicion of Whipple disease (group C, 132 patients). MEASUREMENTS: Small-intestinal biopsy specimens were tested by polymerase chain reaction for T. whippelii DNA and examined for histopathologic abnormalities. RESULTS: All patients with negative histologic findings also had negative results for T. whippelii DNA. CONCLUSIONS: T. whippelii occurs only rarely in intestinal mucosa that lacks histopathologic evidence of Whipple disease. The human small intestinal mucosa is an unlikely reservoir for this organism.

Actinomycetales↗

PubMed1981

Galactosyltransferase activities in rat intestinal mucosa. Inhibition of nucleotide pyrophosphatase.

Nucleotide pyrophosphatase, a Zn2+-dependent enzyme catalyzing the hydrolysis of sugar nucleotides, generally interferes with glycosyltransferase assays. Certain tissues such as intestinal mucosa are particularly rich sources of nucleotide pyrophosphatase activity. The inhibition of nucleotide pyrophosphatase without affecting glycosyltransferase activities by the removal of Zn2+ allows for the assay of galactosyltransferases in rat intestinal particulate fractions. Inactivation of nucleotide pyrophosphatase was achieved by preincubation of particulate enzyme preparations in the presence of EDTA. Addition of Mn2+, required for the galactosyltransferase assays, did not reactivate the nucleotide pyrophosphatase. The presence of 0.05% (w/v) soybean trypsin inhibitor was required during the preparation of intestinal mucosa homogenates and enzyme assays to protect the UDP-galactose: N-acetylglucosaminyl galactosyltransferase from inactivation.

Animals↗

PubMed1972

Peptide hydrolases in the bruch border and soluble fractions of small intestinal mucosa of rat and man.

Peptide hydrolases, catalyzing the hydrolysis of 13 dipeptides and 5 tripeptides into their respective amino acids, were studied in small intestinal mucosa and other tissues, in man and in the rat. Studies on the subcellular distribution of these enzymes showed enzyme activities in both the soluble and brush border fractions of the rat small intestinal mucosa, the former constituting 80-90% and the latter 10-15% of the total activity. Zymogram studies of peptide hydrolases, in both fractions, yielded multiple bands indicating multiple zones of enzyme activity. With most substrates a rather broad range of enzyme activities was observed in the soluble fraction differing only slightly from substrate to substrate, the exception being when L-leucyl-L-proline was used: this latter led to a zymogram pattern which was quite distinct. The synthetic substrates, L-leucyl-beta-naphthylamide and L-leucinamide appeared to be hydrolyzed by two electrophoretically distinct enzymes, different from those hydrolyzing other leucyl-containing peptide substrates. Zymogram patterns of the brush border membrane fraction were quite different from those of the soluble fraction of rat small intestine indicating that enzymes from the two sources may be different. No comparable human data were obtained.Peptide hydrolases in the soluble fractions of various organs from the same species gave similar zymogram patterns, while those from the plasma membrane-bound fractions of different organs in the same species were peculiar to each organ. From these data, it is suggested that peptide hydrolases in the brush border and the soluble fractions of small intestine are distinct enzymes and may play different roles in cellular function.

Amides↗

PubMedDate not supplied

[Protein spectrum and aminotransferase activity in the abomasum and small intestine mucosa of newborn calves].

Study of newborn infants established that the total content of soluble proteins in the abomasum and intestine mucosa does not vary significantly. In the composition of the small intestine mucosa proteins the content of prealbumin and albumin increases. The aspartate aminotransferase activity of the studied tissues becomes more intensive with the calves age.

Abomasum↗

PubMed1987

Physiological regulation of transepithelial impedance in the intestinal mucosa of rats and hamsters.

Isolated intestinal segments from rats or hamsters were recirculated with balanced salt solutions containing fluorocarbon emulsion to provide 6 vpc oxygen. The lumen contained an axial Ag-AgCl electrode, and the serosal surface was surrounded by a cylindrical shell of Ag-AgCl. Transmural impedances were measured at frequencies from 0.01-30 kHz before and after removal of the mucosal epithelium. The resistance of intercellular junctions, RJ, the distributed resistance of the lateral spaces, RL, and the distributed membrane capacitance, CM, were computed from the relations between frequency and impedance. Activation of Na-coupled solute transport by addition of glucose, 3-0-methyl glucose, alanine or leucine caused two- to threefold decreases of transepithelial impedance. Typical changes induced by glucose in hamster small intestine were RJ 30----13 omega, RL 23----10 omega, and CM 8----20 microF (per cm length of segment). Half maximal response occurred at a glucose concentration of 2-3 mM. The area per unit path length of the junctions (Ap/delta chi = specific resistance divided by RJ) in glucose activated epithelium was 3.7 cm in hamster midgut and 6.8 cm in rat. These values are close to the 4.3 cm estimated independently from coefficients of solvent drag and hydrodynamic conductance in glucose-activated rat intestine in vivo. The transepithelial impedance response to Na-coupled solute transport was reversibly dependent upon oxygen tension. It is proposed that activation of Na-coupled solute transport triggers contraction of circumferential actomyosin fibers in the terminal web of the microvillar cytoskeletal system, thereby pulling apart junctions and allowing paracellular absorption of nutrients by solvent drag as described in the previous accompanying paper. Anatomical evidence in support of this hypothesis is presented in the following second accompanying paper.

Animals↗

PubMed1980

[Increase in alkaline phosphatase activity in small intestine mucosa in high fat diets].

The activity of alkaline phosphatase in small intestine mucosa was increased by about 40% in rats adapted to a high fat diet in comparison to high-carbohydrate-adapted animals. As high fat-feeding leads to an increase in the intestine's capacity to absorb fat, this finding is consistent with the hypothesis that alkaline phosphatase in the small intestine epithelium plays a role in fat absorption.

Alkaline Phosphatase↗

PubMed1984

The small-intestinal mucosa in patients with Crohn's disease assessed by scanning electron and light microscopy.

Small-intestinal mucosal biopsy specimens obtained by a Watson capsule were assessed by light (LM) and scanning electron (SEM) microscopy in 18 patients with various sites of Crohn's disease and in 6 healthy controls. By means of LM, partial villous atrophy of the upper small-intestinal mucosa was assessed in six patients. With the use of SEM a further seven patients were shown to have mucosal abnormalities of possible clinical significance. These specimens showed a convoluted villous pattern at low-power SEM and some also enterocyte irregularity, bulging, and surface ultrastructural distortion at medium- and high-power SEM. The medium- and high-power mucosal alterations were unevenly distributed. The high prevalence of abnormalities of the upper small-intestinal mucosa in patients with Crohn's disease elsewhere in the gastrointestinal tract adds further weight to the concept of a diffuse involvement along the entire gastrointestinal tract in Crohn's disease.

Adolescent↗

PubMed1973

Familial hypophosphatemic rickets: defective transport of inorganic phosphate by intestinal mucosa.

Uptake of inorganic phosphate is impared in intestinal mucosa from hemizygous males and heterozygous females with X-linked familial hypophosphatemic rickets. Considerable intrafamilial and interfamilial variation in uptake of inorganic phosphate is observed in affected patients. Uptake by normal mucosa is concentrative and energy-dependent, and is mediated by at least two systems with widely different affinities. These results lend direct support to the thesis that the primary metabolic disturbance in this disease results from impaired transport of inorganic phosphate in kidney and gut.

Biological Transport↗