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 883 records · Page 49Linked to original sources
PubMed1984

Purification and characterization of cytochrome P-450 specific for prostaglandin and fatty acid hydroxylase activities from the microsomes of rabbit small intestinal mucosa.

Earlier studies (Kusunose, E., Kaku, M., Ichihara, K., Yamamoto, S., Yano, I., & Kusunose, M. (1984) J. Biochem. 95, 1733-1739) showed that a form of cytochrome P-450 isolated from microsomes of rabbit small intestinal mucosa had the highest prostaglandin A1 (PGA1) hydroxylase activity so far reported among cytochrome P-450s. The present paper describes the procedure for the purification and further characterization of this cytochrome (designated as cytochrome P-450ia). Cytochrome P-450ia had a monomeric molecular weight of 53,000. The CO-difference spectra of its reduced form showed a maximal absorption at 451 nm, and the absolute spectra of its oxidized form indicated that cytochrome P-450ia was present largely in the low-spin state, and partially in the high-spin state. The cytochrome efficiently catalyzed the hydroxylation of fatty acids as well as prostaglandins in a reconstituted system containing cytochrome P-450, NADPH-cytochrome P-450 reductase, phospholipid, and cytochrome b5. PGA1 was the most efficient substrate, followed by myristate, laurate, palmitate, caprate, and PGE1 or PGE2. Among phospholipids, didecanoyl- and dilauroylphosphatidylcholines had the most stimulatory effect for both activities. 20-Hydroxy PGA1 was identified as the hydroxylation product of PGA1 by gas chromatography-mass spectrometry and mass fragmentography; the possibility of 19-hydroxy PGA1 being the product was excluded. In contrast, both omega- and (omega-1)-hydroxy fatty acids were identified as hydroxylation products of fatty acids. Cytochrome P-450ia had no detectable activity toward aminopyrine, benzphetamine, p-nitroanisole, 7-ethoxycoumarin, benzo(a)pyrene, or hexadecane.

Animals↗
PubMed1983

Carotene-cleavage activity in chick intestinal mucosa cytosol: association with a high-molecular-weight lipid-protein aggregate fraction and partial characterization of the activity.

A fluorescent high-molecular weight lipid-protein aggregate was isolated from the cytosol of chick intestinal mucosa or liver by gel filtration on columns of Sepharose 4B or 6B. This aggregate exhibited carotene-cleavage activity. On incubation of this aggregate, dissociation occurred and low-molecular weight fractions containing Cu and Zn and exhibiting carotene-cleavage activity were found. This fraction appeared on sodium dodecyl sulphate polyacrylamide electrophoresis to have a molecular weight of 7000-11000 and resembled the previously described Cu chelatins in amino acid composition. Carotene cleavage may be effected by a copper-zinc metalloprotein of low-molecular weight, associated in intestinal cytosol with a lipid-protein aggregate.

Animals↗
PubMed1987

[Scanning electron microscopy of microbes and their mechanism of attachment to human small intestinal mucosa].

In connection with the electron-microscopy of bioptic material from the upper small intestine of children with intestinal diseases and diarrhea (10 months to 8 years) we found some cases of fungus infection (26%) besides many cases of bacterial attachment to the intestinal epithelium (72%). On the intestinal wall normal yeasts, pseudomycelium and common mycelium are visible. Partly the epithelium was entirely covered with mycelium. In some cases the hyphae invaded in the intestinal wall. The epithelium and the villi are not or only slightly altered. This gives the reason to believe that the fungi participate in inducing diarrhea. After medicamentous treatment with nystatine-preparations in some cases the health state of these children was improved.

Bacteria↗
PubMed1980

Metabolism of extracellular glutathione in rat small-intestinal mucosa.

Metabolism of exogenous glutathione was investigated in suspensions of freshly isolated rat small-intestinal mucosal cells. The cells catalyzed the oxidation of reduced glutathione (GSH) to glutathione disulfide (GSSG). Neither serine . borate nor methionine significantly influenced this reaction. Formed GSSG was further metabolized as indicated by its disappearance from the medium. Degradation of GSSG was stimulated by methionine and inhibited by serine . borate. Separation and identification of GSSG metabolites were achieved by high performance liquid chromatography. The results indicate that the preferred route for GSSG metabolism to the constituent amino acids in small intestine, is by hydrolytic removal of the two gamma-glutamyl groups of GSSG to yield cystinyl-bisglycine which is subsequently hydrolyzed to cystine. gamma-Glutamyltransferase activity was compared in isolated intestinal, kidney and liver cells using gamma-glutamyl-p-nitrocarboxyanilide as substrate. Kidney cells were approximately 5-fold and 150-fold more active than intestinal and liver cells, respectively. Serine . borate markedly inhibited, and glycyl-glycine stimulated, hydrolysis of gamma-glutamyl-p-nitrocarboxyanilide in all cell types confirming the involvement of gamma-glutamyltransferase in the reaction. The hydrolysis of gamma-glutamyl-p-nitrocarboxyanilide was inhibited to approximately the same extent by either GSH or GSSG suggesting that both compounds interact at the donor site of gamma-glutamyltransferase. Comparison of the rates of glutathione metabolism by isolated intestinal and kidney cells suggests that the intestinal contribution to the degradation of extracellular glutathione may be physiologically more important than has previously been assumed.

Animals↗
PubMed1984

Biosynthesis of apolipoprotein C-III in rat liver and small intestinal mucosa.

We have examined the biosynthesis of rat apolipoprotein C-III in the small intestine and liver. The primary translation product of its mRNA was recovered from wheat germ and ascites cell-free systems. Comparison of its NH2-terminal sequence with the NH2 terminus of plasma high density lipoprotein-associated apolipoprotein C-III showed that apo-C-III was initially synthesized as a preprotein with a 20 amino acid long NH2-terminal extension: Met-X-X-X-Met-Leu-Leu-X-X-Ala-Leu-X-Ala-Leu-Leu-Ala-X-Ala-X-Ala. Co-translational cleavage of the cell-free translation product by signal peptidase generated a polypeptide with the same NH2 terminus as the mature protein (X-Glu-X-Glu-Gly-Ser-Leu-Leu-Leu-Gly-Ser-Met). Therefore, this apolipoprotein does not undergo post-translational proteolytic processing like two other high density lipoprotein-affiliated proteins, proapo-A-I and proapo-A-II. The mRNA encoding apolipoprotein C-III comprises 0.4% of the translatable RNA species in adult rat liver and 0.14% of the translatable RNA species in small intestinal epithelium. Acute fat feeding with a triglyceride meal resulted in a 2-fold increase in intestinal preapo-C-III mRNA accumulation but no change in the levels of preproapo-A-I mRNA. Thus, the acute response of the apo-A-I and C-III genes to triacylglycerol absorption differs.

Amino Acid Sequence↗
PubMed1995

Characterization of mucus glycoproteins in the intestinal mucosa of the African elephant (Loxodonta africana) following lectin histochemistry.

The glycoproteins of the small intestines, caecum and colon of three adult elephants and one recently weaned elephant calf were examined by means of lectin histochemistry. Tissue sections were histochemically stained with peroxidase-labelled concanavalin A (Con A), asparagus-pea (TPA), peanut (PNA) and wheat-germ (WGA) lectins. Con A and TPA showed no binding activity in the intestinal tract of the adult elephants or the duodenum and ileum of the elephant calf, but did show a small amount of binding activity in the caecum and colon of the calf. WGA bound very intensely throughout the intestinal tracts of the adults and of the calf--especially with the goblet cells located in the crypts of Lieberkuhn and the glands of Brunner--decreasing in intensity towards the luminal surface of the intestinal tract. PNA stained the glands of Brunner of the duodenum faintly and the goblet cells of the ileum moderately, with no staining of the caecum and faint staining of the colon. These results show the distribution of Con A-, WGA-, PNA- and TPA-binding sites, and the changes that take place in the type of glycoprotein secreted after a change in the diet of the animal.

Animals↗
PubMed1997

Review article: Pathophysiology of the intestinal mucosa in inflammatory bowel disease and arthritis: similarities and dissimilarities in clinical findings.

Although apparently dissimilar in both structure and function, the gut and locomotor system are linked by a number of clinical syndromes in which both are involved. In inflammatory bowel disease, intestinal mucosal inflammation is the primary problem, but may be associated with both axial and peripheral arthropathies. In the seronegative spondyloarthropathies the primary problem is in the locomotor system, but intestinal abnormalities may also be present. In addition, non-steroidal anti-inflammatory drugs used in their treatment, may cause a distinct enteropathy which may be confused with the disease-related intestinal abnormalities. The clinical, histological and genetic features of these conditions are examined in order to assess their relationship and the central role of the intestinal mucosa in their pathogenesis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Lamina propria lymphocytes, not macrophages, express CCR5 and CXCR4 and are the likely target cell for human immunodeficiency virus type 1 in the intestinal mucosa.

Most human immunodeficiency virus type 1 (HIV-1) infections are acquired via mucosal surfaces, and transmitted viruses are nearly always macrophage-tropic, suggesting that mucosal macrophages participate in early HIV-1 infection. Mucosal lymphocytes isolated from normal human intestine expressed CD4 (14,530+/-7970 antibody-binding sites [ABSs]/cell), CCR5 (2730+/-1524 ABSs/cell), and CXCR4 (2507+/-1840 ABSs/cell), but intestinal macrophages, which also expressed CD4 (2959+/-2695 ABSs/cell), displayed no detectable CCR5 or CXCR4 ABS. The absence of CCR5 on intestinal macrophages was not due to expression of the Delta32 deletion allele because matched-blood monocytes expressed CCR5. CCR5(+)CXCR4(+) intestinal lymphocytes supported both R5 (BaL) and X4 (IIIB) HIV-1 replication, whereas the CCR5(-)CXCR4(-) macrophages were not permissive to either isolate or other laboratory isolates (ADA and DJV) and primary isolates (MDR 24 and JOEL). In the intestinal mucosa, lymphocytes, not macrophages, are the likely target cell for R5 (and X4) HIV-1 and are the major source of HIV-1 production during early infection.

CD4 Antigens↗
PubMedDate not supplied

[Conversion of beta-carotene and some beta-apocarotinoids under the effect of substances from the intestinal mucosa].

Products of cleavage of beta-carotene and certain apocarotenoids (beta-apo-4', 8', 10', and 12'-carotenols and citranaxanthol) were studied, and the dynamics of their generation in the presence of an enzyme preparation isolated from rabbit intestinal mucosa was determined. The data suggest that metabolism of beta-apocarotenols involves the production of retinal and beta-apo-14'-carotenal mediated by enzymes different from beta-carotene-15,15'-dioxygenase, which converts beta-carotene to retinal. A scheme of metabolic conversion of beta-carotene is discussed.

Animals↗
PubMed1992

[Decreased intraepithelial lymphocytes in the intestinal mucosa in children with malnutrition and parasitic infections].

In Gabon, 15 children aged 13 to 36 months admitted for malnutrition with chronic diarrhea underwent a small bowel biopsy for detection of parasites in the duodenal contents and histologic evaluation of the intestinal mucosa. In every case, intraepithelial lymphocyte counts (IELC) were under the lower limit of normal for children and adults, regardless of whether or not parasites were found. Partial villous atrophy was a consistent finding. Proportion of lymphocytes among intraepithelial cells was 7.4% in the 6 children with no parasitic infection, 7.9% in the children with giardiasis, and 8.1% in the children with strongyloidiasis. Appropriate treatment of the parasitic infections was quickly followed by resolution of the diarrhea in the nine patients with demonstrable intestinal parasites. These data should be compared with the well documented lymphocyte function anomalies associated with protein-calory malnutrition. The fall in IELC and lack of response to local anigenic stimulations are features of malnutrition.

Atrophy↗
PubMed1999

Aldehyde dehydrogenase from rat intestinal mucosa: purification and characterization of an isozyme with high affinity for gamma-aminobutyraldehyde.

In rat adrenal gland and gastric mucosa putrescine is efficiently oxidized to GABA via gamma-aminobutyraldehyde (ABAL) by action of diamine oxidase and aldehyde dehydrogenase. Having turned our attention on the rat intestinal mucosa, where putrescine uptake and diamine oxidase are active, we have purified and characterized an aldehyde dehydrogenase optimally active on gamma-aminobutyraldehyde. A dimer with a subunit molecular weight of 52,000, the native enzyme binds ABAL and NAD+ with high affinity: at pH 7.4, Km values are equal to 18 and 14 microM, respectively. Affinity for betaine aldehyde is much lower (Km = 285 microM), but the efficiency is equally good, thanks to a high value of V. Unaffected by disulfiram and Mg2+, the enzyme is activated by high NAD+ concentrations (Vnn = 1.6 x Vn) and is competitively inhibited by NADH. According to the best fitting model, the dimeric enzyme only binds one NADH and the mixed complex enzyme-NAD(+)-NADH is inactive. The increase of activity promoted by NAD+ can therefore be ascribed to an allosteric effect, rather than to the activation of a second reaction center. Highly stable at pH 6.8 in the presence of dithiothreitol and high phosphate concentrations, ABALDH is inactivated by ion-exchange resins and by cationic buffers. Our results show that the enzyme can be effectively involved in the metabolism of biogenic amines and, with a K(m) for ABAL lower than 20 microM, in the synthesis of GABA.

Aldehyde Dehydrogenase↗