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PubMed1992

Estradiol binding components in intestinal mucosa of female rats.

The presence of estrogen binding components (EBC) in intestinal mucosa of female rats was investigated by competitive-binding assay using radiolabelled and nonlabelled estradiol 17 beta (E2). EBC were found exclusively in the nuclear fraction and were absent from the cytosolic and from the microsomal fractions. Two types of nuclear EBC with different binding characteristics and capacities were found: Kd1 = 4.8 +/- 0.8 nM, n1 = 18.4 +/- 4.2 fmol/mg protein (n1 = 83.4 +/- 12.5 fmol/mg DNA) and Kd2 = 31.1 +/- 6.8 nM, n2 = 91.1 +/- 18.5 fmol/mg protein (412.7 +/- 80.0 fmol/mg DNA). Type 1 component showed slightly greater affinity for estrogens as compared to progesterone and dexamethasone whereas type 2 component bound other competitors with even greater affinity than E2.

Animals↗
PubMed1982

Ascorbic acid uptake in guinea pig intestinal mucosa.

Cellular accumulation of ascorbic acid was investigated in vitro in distal intestinal mucosa of guinea pig. With 14C-ascorbic acid present at 8 microM/L in the bathing media, tissue/media (T/M) concentration ratios of at least 5 were routinely achieved. Recently absorbed ascorbic acid appeared to be free in solution in the cellular fluid in that it diffused from tissue exposed to poisons with a disappearance half-time of approximately 10 minutes. Ascorbic acid uptake was highly dependent on the presence of sodium in the bathing media; total Tris substitution resulted in a 97% decrease in uptake. Also, metabolically depleted tissue did not accumulate ascorbic acid against a concentration gradient. Uptake of 14C-ascorbic acid from a bathing solution concentration of 8 microM/L was reduced 67% in the presence of 0.8 mM/L nonlabeled ascorbic acid. Recently absorbed 14C-ascorbic acid moved more rapidly back into the lumen when the luminal solution contained nonlabeled ascorbic acid (5 mM) than when it contained mannitol (5 mM). This demonstration of counter transport substantiates a carrier mechanism in the brush border.

Animals↗
PubMed1995

Thermal and pH stabilities of alkaline phosphatase from bovine intestinal mucosa: a FTIR study.

The inactivation of alkaline phosphatase (AP) from bovine intestinal mucosa caused by lowering the p2H from 10.4 to 5.4 or by increasing the temperature from 25 degrees C to 70 degrees C were not followed by significant FTIR changes, indicating that the native conformation of AP was preserved under these conditions. Further decrease of p2H from 5.4 to 3.4 leaded to small infrared spectral changes of AP in the amide I' and amide II regions that were similar to the infrared spectral changes of AP induced by raising the temperature from 70 degrees C to 80 degrees C. The increase of temperature from 70 degrees C to 80 degrees C promoted the formation of intermolecular beta-sheets at the expense of some alpha-helix structures as evidenced by the appearance of the 1684 cm-1 and 1620 cm-1 component bands and the disappearance of the 1651-1657 cm-1 component band. This conformational change was followed by a sharp increase of the 2H/H exchange rate. CD spectra confirmed the FTIR results and were very sensitive to the variation of alpha-helix content while FTIR spectra were more receptive to the changes of beta-sheet structures.

Alkaline Phosphatase↗
PubMed1976

Biosynthesis of triacylglycerols by rat intestinal mucosa in vivo.

The structure of mucosal triacylglycerols was studied in rat intestinal mucosa in vivo during the absorption of a low molecular weight fraction of butter oil and of the corresponding free fatty acids of medium and long chain length. The mucosal lipids were isolated by solvent extraction and the acylglycerol structures were determined by combined AgNO3- thin-layer chromatography and gas-liquid chromatography techniques and stereospecific analysis. Evidence was obtained for a rapid biosynthesis of triacylglycerols from diacylglycerols arising from the operation of both the monoacylglycerol and the phosphatidic acid biosynthetic pathways. Both sn-1,2- and sn-2,3-diacylglycerols appeared to be converted to triacylglycerols at significant rates, but a preferential utilization of sn-1,2-diacylglycerols could not be excluded. Endogenous dilution varied from a miniumum of 5% during triacylglycerol biosynthesis from monoacylglycerols to 15% during their synthesis from free fatty acids, and was characterized by a preferential placement of the endogenous acids in the sn-3 and 2 positions of the triacylglycerol molecules. Exogenous myristic acid was preferentially associated with the sn-3 position, and stearic acid became preferentially bound to the sn-1 position. The complexity of the triacylglycerol end products prevented an exact estimate of the contribution of the phosphatidic acid pathway, but the acylglycerol structures were compatible with a minimum of 20% of total triacylglycerol yield at all times.

Animals↗
PubMed1989

Expression of membrane receptors and (proto)oncogenes during the ontogenic development and neoplastic transformation of the intestinal mucosa.

The functional relationship between membrane receptors involved in signal transduction and (proto) oncogene expression has been explored during the ontogenic development and differentiation of the intestinal mucosa in man and rat. The present review develops detailed picture of the current understanding of some mechanisms underlying growth and function of normal, immortalized and cancerous intestinal epithelial cells.

Animals↗
PubMed1987

Identification of a new fimbrial structure in enterotoxigenic Escherichia coli (ETEC) serotype O148:H28 which adheres to human intestinal mucosa: a potentially new human ETEC colonization factor.

Three important fimbrial colonization factor antigens (CFAs) designated CFA/I, CFA/II, and E8775 were identified originally in some human enterotoxigenic Escherichia coli (ETEC) strains because of their mannose-resistant hemagglutination properties. To identify CFA, in strains lacking mannose-resistant hemagglutination properties we exploited the ability of human ETEC strains to adhere to human proximal small intestinal mucosa. ETEC strain B7A (O148:H28) was selected for study because it belongs to an epidemiologically important serotype and does not produce a known CFA, and yet it is known to be pathogenic and cause diarrheal disease in human volunteers. Results of an human enterocyte adhesion assay indicated that some bacteria in cultures of B7A produced adhesive factors. To select for such bacteria, cultured human duodenal mucosal biopsy samples were infected with B7A for up to 12 h, after which time a large percentage of the mucosal surface became colonized by bacteria. A new fimbrial structure morphologically distinct from CFA/I, CFA/II, and E8775 fimbriae and consisting of curly fibrils (approximately 3 nm in diameter) was readily identified when bacteria were subcultured from the mucosa and examined by electron microscopy. Identical fimbriae were produced by ETEC strain 1782-77 of the same serotype. Identification of these fimbriae only on bacteria subcultured from human intestinal mucosa strongly suggests that they promote mucosal adhesion of ETEC serotype O148:H28 and thus represent a potentially new human ETEC CFA.

Bacterial Adhesion↗
PubMed2001

[Comparative study of chromatography-mass spectrography of microorganism's chemical markers in blood and intestinal mucosa bioptats].

Fatty acids, that are microorganism's markers in blood and jejunum's, ileum's, and large intestine's bioptats of the patients with irritable bowel syndrome were investigated with gas chromatography. Markers of Cl. perfringens, Cl. difficile, Enterococcus, Streptomyces, Enterobacterial, Klebsiella, E. coli, Peptostreptococcus, Candida Albicans, genus of Streptococcus, of Staphylococcus, of Fusobacterium sp and others microorganisms were revealed. Settling of intestinal mucosa was the same in jejunum, ileum and large intestine (0.5-1.3) x 10(10) cells/gr. and was approximately the same as microorganism's concentration in feces (1.8 x 10(11) cells/gr). Correlation of blood and bioptats markers was demonstrated in the most patients. The possibility to use specific fatty blood acids as microorganisms markers in preliminary diagnosis of mucosa microflora changes is discussed.

Bacterial Infections↗
PubMed1978

[Investigation of the bile acid metabolism of children with subtotal atrophy of intestinal mucosa (author's transl)].

A secretin-pancreozymin test was conducted with 43 gastroenterologically healthy children and 12 patients with subtotal atrophy of intestinal mucosa. While the pancreas enzymes were normal, the patients with coeliac disease reacted to the injection of the peptide hormones by producing a larger volume of secretion than did the control group. Despite the increased secretion there was at the same time a significantly higher concentration of bile acids in the duodenal juice. Analysis of the bile acid distribution indicated no deviation from the norm. There was, however, a striking discrepancy between the bile acid and the bilirubin excretion in the children with subtotal atrophy, whose bilirubin secretion, compared to that of the control group, was greatly reduced.

Adolescent↗
PubMedDate not supplied

Increased levels of NF-kappaB inhibitors (IkappaBalpha and IkappaBgamma) in the intestinal mucosa of Crohn's disease patients during infliximab treatment.

The treatment with infliximab is employed successfully in Crohn's disease (CD) but predictors of efficacy are lacking. Activation of the transcription factor NF-kB has been demonstrated in CD and its inhibition is one of the mechanisms by which anti-inflammatory agents exert their effects. We evaluated the production of TNFalpha by peripheral blood mononuclear cells (PBMC) and the levels of NF-kappaB family molecules in the intestinal mucosa during infliximab therapy in 12 patients. TNFalpha was assayed on supernatants of PBMC culture stimulated with PHA or LPS. Immunohistochemistry was also done on intestinal biopsies. In six patients, Western blot analysis of the NF-kappaB subunit Rel-A, and its inhibitors IkappaBalpha and IkappaBgamma was performed on intestinal biopsies and PBMC. The TNFalpha production by LPS stimulated PBMC showed mild changes, while it was increased by PHA-stimulated PBMC after treatment. The number of inflammatory cells in the intestinal mucosa was reduced (p<0.002) by the treatment. In five out of six cases we detected an increase of the IkappaBalpha and IkappaBgamma)inhibitor levels in intestinal biopsies after treatment. An increase of IkappaB inhibitors levels could be one of the mechanisms by which infliximab decreases NF-kappaB activity and exerts its anti-inflammatory effects.

Adult↗
PubMed1990

Effect of estrogen-receptor interaction on the levels of fatty acid-binding proteins and spectra of free acids in small intestinal mucosa of rabbits.

Data on the possibility of estrogens to regulate absorption of free fatty acids (FFA) during absorption of lipids in small intestine with associated estrogen-receptor interaction and changes in fatty acid-binding protein (FABP) levels are reported. In particular, characteristics of cytoplasmic estrogen receptors, estradiol metabolism, FABP levels and spectra of FFA in FABP fraction were studied in small intestinal mucosa of sexually mature and immature female rabbits, intact or after ovariectomy and estradiol dipropionate administration. The dissociation constants (Kd) and number of binding sites were determined in coordinates of Scatchard. FABP levels were demonstrated spectrophotometrically after ultracentrifugation (K-32M) and gel filtration (G-75). FFA composition of FABP fraction, chyme and enterocytes were analyzed by a chromatographic method (Tsvet-110). Levels of body estrogens were monitored by high-performance liquid chromatographic analysis (Tsvet-306) of estrogens in daily urine. The study has demonstrated a specific relation between FABP levels and their lipid component, FFA, on the one hand and endo- and exogenous estrogen levels on the other hand, in female rabbits maintained on a standard fat-free diet.

Age Factors↗
PubMed1984

Morphometric analysis of small intestinal mucosa. I. Methodology, epithelial volume compartments and enumeration of inter-epithelial space lymphocytes.

Morphometric techniques for quantitating cytologic and volumetric changes in small intestinal mucosae are described: measurements were controlled with respect to a constant 'test area' of muscularis mucosae, thus following valid comparisons between normal and damaged mucosae. Procedures for enumerating cell populations within mucosal volume compartments are illustrated by analyzing lymphocytes within surface epithelium. These techniques serve to distinguish (i) absolute cell counts from (ii) relative cell counts ("densities") the latter being shown to be considerably affected by changes in epithelial volume. They also permit construction of mathematical models e.g. cubes of equivalent volume, volume-density graphs, proportional volumes, which are illustrated. Use of these morphometric procedures showed that there is no major difference in epithelial lymphocyte populations between untreated coeliac disease, and control, mucosae. The data thus fail to support the widespread view that "infiltration" of coeliac disease epithelium by lymphocytes represents a local cell-mediated immune reaction to gluten.

Celiac Disease↗
PubMed1975

The small-intestinal mucosa in cow's milk allergy.

Two infants investigated for allergy to cow's milk proteins exhibited a local reaginic reaction in the small intestine after ingesting cow's milk, as shown by increased mucosal IgE plasma-cells and degranulation of mast cells. IgM plasma-cells and the staining of connective tissue and basement membranes with antisera to IgG and C3 complement were also increased, indicating several simultaneous immune reactions in the intestinal mucosa. These findings may provide a sound basis for diagnosis of such an allergy and for the treatment of similar patients with disodium cromoglycate.

Biopsy↗
PubMed1989

The effect of chronic parenteral administration of cadmium on isoenzyme levels of alkaline phosphate in intestinal mucosa.

Chronic administration of cadmium chloride to rats (13.3 mumol/kg body wt per dose subcutaneously) produced a decrease in the activity of alkaline phosphatase in the intestinal mucosa to less than half that in control rats by the time cumulative doses of between 30 and 48 mumol had been administered. The reduced level of activity remained approximately steady following further dosing. Three isoenzymes of intestinal alkaline phosphatase were separated electrophoretically. Chronic cadmium treatment markedly decreased the proportion of the 2 isoenzymes with lower electrophoretic mobility. Some analogies are drawn between the effect of cadmium administration, and magnesium deficiency on changes in intestinal alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1997

Lipid modifications of microsomes isolated from villus and crypt zones of bovine intestinal mucosa: relationship with fatty acid binding protein.

The present studies were conducted to examine the fatty acid composition of microsomal lipids of bovine small intestine. Microsomes and cytosol were isolated from mucosal scrapings enriched with villus and crypts cells, and the following studies were conducted to: 1) analyse fatty acids from microsomal lipids; 2) incorporate 1-14C oleic acid to microsomal lipids; and 3) bind 1-14C oleic acid to cytosolic proteins of villus and crypt zone. The results of these studies demonstrated that: (1) the major unsaturated fatty acids of microsomes were oleic (C18:1 n-9), linoleic (C18:2 n-6) and arachidonic acids (C20:4 n-6), which increased from crypt to villus tip of the bovine intestinal mucosa; (2) gel filtration chromatography indicated that the low-molecular weight cytosolic proteins obtained from superficial mucosal scrapings contained the greatest oleic acid binding activity; (3) the incorporation of 1-14C oleic acid to microsomes was higher in phospholipids, triglycerides and cholesterol esters from villus than in crypts zones; (4) the protein content of cytosol and microsomes was longer in villus zones than in crypts zones; (5) the peroxidizability index showed the highest value in villus microsomes.

Alkaline Phosphatase↗
PubMed1966

Effect of neutral alpha- and omega-amino acids and basic alpha-amino acids on uptake of L-histidine by intestinal mucosa, testis, spleen and kidney in vitro: a comparison with effect in brain.

1. The effect of the D- and L-isomer of neutral alpha-amino acids, of omega-amino acids, and of basic L-alpha-amino acids on uptake of L-histidine in vitro has been investigated in intestinal mucosa, testis, spleen and kidney cortex, and compared with the effect in brain.2. Neutral alpha-amino acids produced inhibition that was in general greater the longer the carbon chain of the inhibiting amino acid. There were minor variations with different tissues.3. omega-amino acids produced little or no inhibition, with only slight variation between tissues. There was a tendency towards less inhibition the longer the carbon chain.4. The effect of basic amino acids varied with different tissues. With one exception, all produced significant inhibition with intestinal mucosa and testis. With spleen and kidney, inhibition was slight or absent, and resembled the effect produced by the omega-amino acids. With brain (previously reported elsewhere) the short-chain amino acids produced considerable inhibition, those having longer carbon chains little or none.5. Proline produced significant inhibition in brain and spleen, but none in the other tissues. Tryptophan had no effect with kidney.6. The findings are considered as further evidence for a relation between the extent to which an amino acid can be taken up by a given tissue and the specificity of the transport systems in that tissue. They also support the view that the nature of certain transport systems may vary considerably between different tissues.

Amino Acids↗
PubMed1987

Involvement of capsaicin-sensitive mechanism(s) in the antiulcer defence of intestinal mucosa in rats.

Capsaicin desensitization increases degree and incidence of indomethacin-induced intestinal ulcers in rats, suggesting the existence of a capsaicin-sensitive mechanism(s) in the protection of the intestinal mucosa against indomethacin-induced ulceration. Sensory innervation thus may be involved in the pathogenesis of ulcers of the small bowel, as well as in gastric ulcers. Administration of exogenous CGRP and somatostatin, sensory neuropeptides which are depleted by capsaicin desensitization, does not afford protection toward the capsaicin-induced aggravation of intestinal ulcers. The protective effect of exogenous prostaglandins toward indomethacin-induced intestinal ulceration is not mediated by capsaicin-sensitive nerve fibers.

Animals↗
PubMed1976

[Relationship between the epithelium and the stroma of the small-intestinal mucosa during antigenic stimulation].

The state of cells and intercellular structures, as well as the pattern of interaction between the epithelium and the stroma of the small intestine mucosa following their exposure to microbic toxins were studied in experiments on rabbits using histological, histochemical and immunofluorescent methods. It was established that the immuno-barrier function of the intestine was implemented by the brush border, epithelial cells, their basal membrane, fibres and cells of lamina propia of the mucosa. Damage of the epithelial lining of the mucosa was accompanied by intensification of immunological processes in its stroma, which in the preliminary immunized animals contributed to an increase in the resistance of the epithelial lining to damaging factors of the lumen of the intestine. The lymphoid infiltration of the epithelium of the intestine mucosa represented a manifestation of immunological processes constantly proceeding therein. The epithelial basal membrane which fixed on its surface immunoglobulins coming from lamina propia, retained antigens passing through it from the lumen of the intestine into the thickness of the mucosa's stroma.

Animals↗