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Applicability of the Ussing chamber technique to permeability determinations in functionally distinct regions of the gastrointestinal tract in the rat.

BACKGROUND: Ussing chambers are commonly utilized for in vitro investigations into gastrointestinal permeability. However, their sensitivity and applicability to the small intestine have not been well characterized. METHODS: In order to investigate the effects of experimentally induced damage and the relative contribution of the mucosa and muscularis externa layers to transmural permeability in the small intestine, stomach and colon, normal rat intestinal tissues were mounted in Ussing chambers with or without removal of the muscularis externa or mucosal layers. Gastric tissues were damaged in vivo by exposure to indomethacin (100 mg kg(-1)), while ileal tissues were damaged in vitro by 0.4 M NaCl. Tissue damage was assessed histologically, while permeability parameters included conductance (G), potential difference (PD) and mucosal to serosal flux of horseradish peroxidase (HRP). RESULTS: Damage localized to the tissue edges (edge damage) accounted for 25%-50% of the exposed epithelial length in the ileum, while less than 20% of stomach and colon epithelium was affected by edge damage. In the damaged stomach, a 20% reduction in epithelialization was accompanied by increases in G (P < 0.001) and HRP (P < 0.01) flux. Removal of the muscularis externa did not affect mucosal viability in the undamaged ileum or colon although HRP flux in the colon, but not ileum, was increased (P < 0.01). Removal of the ileal mucosa produced increases in G and HRP flux, while PD was maintained. CONCLUSION: We conclude that the Ussing chamber technique is suitable for application to studies of gastric and colonic permeability in rats. However, owing to the prevalence and extent of edge damage in the small intestine, we would caution against the use of this technique for permeability studies in this region of the gastrointestinal tract in the rat.

Animals↗

Simultaneous administration of lactulose and 51Cr-ethylenediaminetetraacetic acid. A test to distinguish colonic from small-intestinal permeability change.

In normal adults intestinal permeation of ingested 51Cr-ethylenediaminetetraacetic acid (EDTA) is greater than that of lactulose. This difference is abolished in patients with ileostomies, suggesting that it results from colonic permeation of 51Cr-EDTA, which, unlike lactulose, resists bacterial degradation. To investigate the effect of an increase in colonic permeability on absorption of the two molecules, lactulose (5 g) and 51Cr-EDTA (50 microCi) were given orally in isosmolar solution to 11 patients with colitis, and their 24-h urinary excretion measured. By comparison the effect of an increase in small-intestinal permeability induced by ingestion of a hyperosmolar solution (4240 mosm/l) was measured in 10 healthy adults. Hyperosmolar stress increased the 24-h urinary excretion of 51Cr-EDTA above the normal mean + 2 standard deviations (3.31%) in all 10 healthy subjects, and in all of these excretion of lactulose was also increased (greater than 1.06%). In contrast, although seven colitics had a urinary excretion of 51Cr-EDTA above the normal mean + 2 SD, in only two of these patients was recovery of lactulose increased. This suggests that simultaneous administration of lactulose and 51Cr-EDTA may enable permeability changes affecting the colon alone to be distinguished from those involving the small intestine.

Adult↗

Effect of high fat corn oil, olive oil and fish oil on phospholipid fatty acid composition in male F344 rats.

Epidemiological and laboratory animal model studies have provided evidence that the effect of dietary fat on colon tumorigenesis depends on the amount of fat and its composition. Because of the importance of the composition of dietary fat and of tissue membrane fatty acid composition in tumor promotion, experiments were designed to investigate the relative effects of high fat diets rich in omega 3, omega 6 and omega 9 fatty acids and colon carcinogen on the phospholipid fatty acid composition of liver, colon, small intestine, erythrocytes and blood plasma. At 6 wk of age, groups of animals were fed diets containing 5% corn oil (LFCO), 23.5% corn oil (HFCO), 23.5% olive oil (HFOO), and 20.5% fish oil plus 3% corn oil (HFFO). Two weeks later all the animals except the vehicle-treated animals received azoxymethane s.c. once weekly for 2 wk at a dose rate of 15 mg/kg body weight. Animals were sacrificed 5 d later and liver, colon, small intestine and erythrocytes and blood plasma were analyzed for phospholipid fatty acids. The results indicate that the phospholipid fatty acid composition of liver, colon and small intestine of HFCO diet fed animals, were not significantly different from those fed the LFCO diet. The levels of palmitoleic acid and linoleic acid were increased in erythrocytes and blood plasma of the animals fed the HFCO diet compared to those fed the LFCO diet. Feeding the HFOO diet significantly increased the oleic acid content and decreased the linoleic acid and arachidonic acid levels in various organs when compared to the HFCO diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Peritoneal lavage in penetrating injuries of the small bowel and colon: value of enzyme determinations.

The value of lavage alkaline phosphatase determinations following hollow visceral injury was studied. Twenty-nine mongrel dogs were subjected to partial transection of the small intestine or colon, or underwent sham laparotomy. Sequential diagnostic peritoneal lavage was performed. At one hour post injury the lavage red cell count, white cell count, and amylase levels were within normal limits in each group. The lavage alkaline phosphatase, however, was markedly elevated in both bowel-injured groups compared with the sham group. In the five-hour lavage, red cell counts and amylase levels remained normal. White cell counts were now elevated in all three groups, but the results did not distinguish the intestinal injury from the sham model. Lavage alkaline phosphatase was again significantly increased in the injured groups versus the sham model. Serum alkaline phosphatase and amylase levels were normal in all study groups at baseline and one and five hours post injury. This canine study demonstrates the utility of peritoneal lavage alkaline phosphatase levels in identifying isolated small intestine and colon injuries that were otherwise undetected by red cell, white cell, and amylase determinations.

Alkaline Phosphatase↗

ColV increases the virulence of Escherichia coli K1 strains in animal models of neonatal meningitis and urinary infection.

Isogenic Escherichia coli strains, differing in their expression of K1 antigen and ColV plasmid, were studied for their ability to produce disease. Newborn rats were used to test the ability of these strains to colonize the intestine and to produce bacteremia and meningitis; adult rats were used to test their ability to produce urinary tract infection. Colonization of intestine and bladder by K1+ ColV+ E. coli was associated with rapid induction of bacteremia and higher mortalities compared with colonization with K1+ ColV- strains. These findings suggest that the ColV plasmid could play a role in the pathogenesis of human infections.

Animals↗

[Intestinal perforation after preoperative colonic tattooing with India ink].

Since the ability to palpate the bowel is lost in laparoscopic colon surgery preoperative marking of lesions is required to avoid "blind" resection. Endoscopic tattooing with India ink is the agent of choice because of its simplicity and the long-lasting stain. Only few complications have been reported using this technique. We present a case with localized necrosis and retroperitoneal perforation after endoscopic tattooing. Due to the formation of a local inflammatoric pseudotumor laparoscopic resection was impossible and open right hemicolectomy was necessary. Fever, abdominal pain and signs of local peritonitis after endoscopic tattooing should remind clinicians of this rare complication.

Aged↗

Distribution of Escherichia coli heat-stable enterotoxin/guanylin/uroguanylin receptors in the avian intestinal tract.

Pathogenic strains of enteric bacteria secrete small heat-stable toxins (STs) that activate membrane guanylyl cyclase receptors found in the intestine. The intestinal peptide agonists, guanylin and uroguanylin, are structurally related to STs. Receptors for 125I-ST were found throughout the entire length of the intestinal tract of all the birds examined. These receptors were restricted to intestinal epithelial cells covering villi and forming intestinal glands and were not observed in other strata of the gut wall. The most intense labeling of receptors by 125I-ST occurred in the region of the microvillus border of individual enterocytes. There appeared to be a decrease in receptor density distally along the length of the small intestine, although labeling of receptors by 125I-ST was observed throughout the small intestine and colon. Cellular cGMP accumulation responses to Escherichia coli ST and rat guanylin in the domestic turkey and duck were greater in the proximal small intestine compared to the distal small intestine or colon. Brush border membranes (BBM) isolated from the mucosa of proximal small intestine of turkeys exhibited agonist-stimulated guanylyl cyclase activity. The rank order potency for enzyme activation was E. coli ST > uroguanylin > guanylin. Competitive radioligand binding assays using 125I-ST and turkey intestine BBM revealed a similar rank order affinity for the receptors that was exemplified by the Kd values of ST 2.5 nM, uroguanylin 80 nM and guanylin 2.6 microM. It may be concluded that functional receptors for the endogenous peptides, guanylin and uroguanylin, occur in the apical membranes of enterocytes throughout the avian intestine. The receptor-guanylyl cyclase(s) of proximal small intestine were preferentially activated by uroguanylin relative to guanylin, but both endogenous peptides were less potent than their molecular mimic, E. coli ST.

Amino Acid Sequence↗

[Therapy refractory atypical polyarthritis and cryoglobulinemia in a patient with colon carcinoma and palliative intestinal bypass. Differential diagnosis: carcinoma-polyarthritis or bypass arthritis].

The case of a 63 year old woman with mesenteric recurrence of a colonic carcinoma and infiltration of the duodenum is reported. To bypass duodenal stenosis a duodenojejunostomy was performed. Three months later the patient developed severe atypical polyarthritis which led to hospitalization. The arthritis affected large and small joints in an asymmetrical pattern. Fever and Raynaud's phenomenon of both hands accompanied the arthritis. Elevated sedimentation rate, acute phase proteins, cryoglobulinemia and immune complexes were remarkable laboratory findings. Rheumatoid factor was absent. In the subsequent course the polyarthritis was refractory to steroids and nonsteroidal anti-inflammatory drugs. Only treatment with broad-spectrum antibiotics ameliorated the arthritis. Postenteric reactive arthritis, septic arthritis and metastatic arthritis could be excluded. Although the patient had a family history of rheumatoid arthritis and a HLA-type DR4 the diagnosis of rheumatoid arthritis was not very likely since distal interphalangeal joints were affected, rheumatoid factor was absent and antibiotic therapy was successful. The case serves to discuss carcinoma-polyarthritis and bypass-arthritis as the main differential diagnosis.

Adenocarcinoma↗

Parasites and related pathological lesions in the gastrointestinal tract of a seal (Phoka vitulina Linnaeus).

An immature seal, about one-year-old, died a natural death. At autopsy, a large number of Contracaecum osculatum and Pseudoterranova decipiens, as well as some of Anisakis simplex were found in the stomach together with numerous Corynosoma strumosum in the small intestine and colon. Histopathological examination revealed epithelial desquamation, congestion and hemorrhage in the mucosa. There were cellular infiltration and fibroplasia around the nematodes, collapsed nematodes and molted nematode cuticules in the stomach wall. The small intestine and colon underwent severe epithelial desquamation, catarrhal inflammation, and slight inflammatory response consisting mainly of lymhocytes. To the best of our knowledge, this may be the first report on Corynosoma strumosum in Japan.

Animals↗

The relationship between the radiological and clinical features in patients with Crohn's disease.

A study has been made of 93 Japanese patients with Crohn's disease who had not undergone bowel resection at the time of diagnosis during the years 1969 to 1983. Ninety had longitudinal ulcers or a cobblestone appearance or both of the small intestine or colon or both on double contrast barium examination. The incidence of longitudinal ulcers in the small intestine was significantly higher than in the colon (P less than 0.001). Conversely the incidence of cobblestoning was higher in the colon than in the small intestine (P = 0.065). In patients with longitudinal ulceration, there was significantly lower Crohn's disease activity index (CDAI), ESR, and C-reactive protein. Patients with cobblestoning had a significantly higher CDAI, ESR and C-reactive protein, and significantly lower values of albumin, cholesterol in serum, serum iron, haemoglobin, and relative body weight. Our findings indicate that cobblestoning closely correlates with the disease activity of Crohn's disease, and that longitudinal ulceration has a negative correlation. Moreover, our results suggest that the high incidence of cobblestoning and low incidence of longitudinal ulcers in the colon and the reverse in the small intestine reflects the fact that colonic involvement renders the disease more severe than small intestine involvement only.

Adolescent↗

Enterohemorrhagic Escherichia coli O157:H7 requires intimin to colonize the gnotobiotic pig intestine and to adhere to HEp-2 cells.

In a previous study, enterohemorrhagic Escherichia coli (EHEC) O157:H7 with a deletion and insertion in the eaeA gene encoding intimin was used to establish that intimin is required for the organism to attach to and efface microvilli in the piglet intestine (M. S. Donnenberg, S. Tzipori, M. L. McKee, A. D. O'Brien, J. Alroy, and J. B. Kaper, J. Clin. Invest. 92:1418-1424, 1993). However, in the same investigation, a role for intimin in EHEC adherence to HEp-2 cells could not be definitively demonstrated. To analyze the basis for this discrepancy, we constructed an in-frame deletion of eaeA and compared the adherence capacity of this mutant with that of the wild-type strain in vitro and in vivo. We observed a direct correlation between the requisite for intimin in EHEC O157:H7 colonization of the gnotobiotic piglet intestine and adherence of the bacterium to HEp-2 cells. The in vitro-in vivo correlation lends credence to the use of the HEp-2 cell adherence model for further study of the intimin protein.

Adhesins, Bacterial↗

Role of colonization of the upper intestinal tract in the pathogenesis of ventilator-associated pneumonia.

Ventilator-associated pneumonia (VAP) is the most frequent infection in mechanically ventilated patients. Colonization of the gastrointestinal tract, especially the stomach, is believed to be important in the pathogenesis of VAP. However, the literature on this topic is full of contradictory evidence. In the present review, we critically assess the existence and importance of the gastropulmonary route of colonization in the pathogenesis of VAP, and we analyze the differences between studies that show different results. Several preventive regimens (e.g., the use of sucralfate for stress ulcer prophylaxis and modulation of enteral feeding) have been used to prevent gastric colonization and decrease the incidence of VAP. However, none of these regimens has been demonstrated to be unequivocally beneficial. Moreover, recent analyses of the sequences of colonization in patients who develop VAP suggest that gastric colonization may be less important in the pathogenesis of VAP than has been assumed. As a result, the impact of other routes of colonization such as cross-colonization or transfer of rectal bacteria via the skin or other vectors to the respiratory tract may have been underestimated. Knowledge of the relative importance of each of these possible routes of colonization is essential for developing effective measures to prevent VAP.

Bacteria↗

Effects of Maillard browned egg albumin on drug-metabolizing enzyme systems in the rat.

Adult male Sprague-Dawley rats were fed a purified diet containing 5% Maillard browned egg albumin (EA-B) or browned hydrolysed egg albumin (HEA-B) for 10 wk. Control animals were pair-fed a corresponding isocaloric, isonitrogenous non-browned egg albumin (EA-C) or hydrolysed egg albumin (HEA-C) diet. At the end of 10 wk, the rats were killed and hepatic, small intestinal and colonic microsomes and cytosol fractions were prepared by ultracentrifugation. Animals fed EA-B exhibited significantly (P less than 0.05) increased hepatic benzo[alpha]pyrene hydroxylase activity and significantly (P less than 0.05) decreased colonic aminopyrine N-demethylase activity compared to control (EA-C) animals. HEA-B-fed animals also exhibited a significant (P less than 0.05) decrease in colonic aminopyrine N-demethylase activity compared with HEA-C controls, but no significant differences were detected in hepatic or small intestinal enzyme activities in this group. These data suggest that Maillard browned protein products may modify hepatic and/or colonic drug-metabolizing enzyme system activities, and may thus contribute to alterations in the metabolism of endogenous substrates and of exogenous drugs, precarcinogens and other xenobiotics.

Aminopyrine N-Demethylase↗

Regulated expression of the integrin alpha9beta1 in the epithelium of the developing human gut and in intestinal cell lines: relation with cell proliferation.

The integrin alpha9beta1 is one of the recently identified integrins whose expression is restricted to specialized tissues. Its exact function is still unknown. In the present study, we have analyzed the expression of the alpha9 subunit in human fetal and adult small intestinal and colonic epithelia as well as in intestinal cell lines by indirect immunofluorescence, immunoprecipitation, Western blot, and Northern blot. In intact tissues, the antigen was restricted to the basolateral domain of epithelial cells in intestinal crypts at the fetal stage and was absent in the adult. The alpha9beta1 integrin was also detected in the intestinal cell lines HIEC-6 and Caco-2/15. The presence of alpha9beta1 in HIEC-6 was found to be consistent with their proliferative crypt-like status. In Caco-2/15 cells, the integrin was present at high levels in proliferating cells but was downregulated when cells cease to grow and undertake their differentiation. EGF treatment, which is known to maintain Caco-2/15 cells in a proliferative state, resulted in higher levels of alpha9 as compared to control cells. Taken together, these observations suggest a relation between integrin alpha9beta1 expression and proliferation in human intestinal cells.

Blotting, Northern↗

Correlation between intestinal immune response to colonization factor antigen/I and acquired resistance to enterotoxigenic Escherichia coli diarrhea in an adult rabbit model.

Immunoprotection against diarrhea caused by colonization factor antigen/I (CFA/I)-positive, human-associated, enterotoxigenic Escherichia coli was investigated using the adult rabbit intestinal temporary ligation technique. An oral dose of 1 X 10(8) viable cells of enterotoxigenic Escherichia coli strain H-10407 (078:H11:CFA/I) produced diarrhea in all animals challenged. Rabbits allowed to survive this challenge dose were re-challenged approximately six weeks later with the result that four of seven (57%) did not develop diarrhea. Peroral immunization of rabbits with purified CFA/I elicited protection against challenge with strain H-10407; this protection was dose-related and CFA/I-specific. Immunoprotection did not correlate with a systemic antibody response. CFA/I produced a relatively poor immune response in terms of the number of IgM- and IgG-producing cells in the lamina propria of the animals but did elicit a vigorous increase in the number of intestinal IgA- and anti-CFA/I-producing cells. There was a highly significant inverse relationship between the number of IgA- and anti-CFA/I-producing cells in the lamina propria of the rabbits and the diarrhea response to the challenge strain H-10407 (correlation coefficients of -0.616 and -0.678 respectively). It is concluded that anti-CFA/I antibody, probably of the IgA class, is the major immune response to orally administered CFA/I and that this response is highly immunoprotective.

Animals↗