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PubMed1986

Infant mouse model of adherence and colonization of intestinal tissues by enterotoxigenic strains of Escherichia coli isolated from humans.

The ability of enterotoxigenic Escherichia coli H10407, which possesses colonization factor antigen I, to colonize the intestinal mucosa of infant mice was considerably better than that of its colonization factor antigen I-negative derivative H10407-P. The latter strain previously was shown to lack cell adhering ability in vitro and to have a diminished capacity to infect human volunteers as compared with the parent strain. D-Mannose blocked both colonization by an enterotoxigenic E. coli isolate (801) possessing both mannose-resistant and mannose-sensitive adhesins and the in vitro adherence of the strain to intestinal segments of infant mice. A derivative of another enterotoxigenic E. coli strain (lacking both mannose-sensitive and mannose-resistant adhesins obtained by in vivo passage showed a significant increase in colonizing ability in comparison with the parent strain. We conclude that the infant mouse model of infection of intestinal mucosa complemented by in vitro adherence assays with excised intestinal tissue is suitable for the study of the bacterial properties responsible for the various stages of intestinal colonization by human enterotoxigenic E. coli.

Adhesiveness↗
PubMed1995

Bleeding from the endoscopically-identified Dieulafoy lesion of the proximal small intestine and colon.

OBJECTIVES: Our goal was to assess the incidence of the endoscopically-identified small intestinal and colonic Dieulafoy-like lesions in our GI bleeding population and to characterize the clinical and endoscopic features and response to endoscopic therapy. METHODS: Patients with GI bleeding from Dieulafoy lesions were identified from our Bleeding Team and GI laser data bases from August 1984 to September 1993. Clinical and endoscopic information contained within the data bases and from each patient's medical record were retrospectively reviewed. Diagnostic criteria that had been used to endoscopically diagnose a Dieulafoy lesion were arterial bleeding or nonbleeding visible vessel stigmata, all without ulceration or erosion. RESULTS: Nine patients (three male; six female; median age, 70 yr; range, 16-94) were identified from a population of 3059 patients. Symptoms included: melena (2); hematochezia (7); and unstable hemodynamics (3). The mean hemoglobin was 8.4 +/- 2.2 g/dl. There was no significant nonsteroidal antiinflammatory drug or alcohol use. Four patients had small bowel and five patients had colonic Dieulafoy's lesions. Specific sites were: distal duodenum (3); jejunum (1); cecum (1); hepatic flexure (3); and transverse colon (1). The diagnosis was made at initial endoscopy in seven patients, after two endoscopies in one patient, and after four in another patient. Active bleeding was encountered in seven patients (three small bowel; four colon). Endoscopic therapy was successful. Two patients rebled, one from the same site (small bowel) 1 yr later. Both were successfully retreated. There were no complications or deaths. CONCLUSIONS: The endoscopic Dieulafoy lesion of the small bowel and colon is infrequently encountered. The diagnosis is most often made during active bleeding. The endoscopic diagnosis requires an aggressive approach, including repeated endoscopy. Endoscopic therapy of proximal small intestinal and colonic Dieulafoy lesions is safe, effective, and should be performed.

Adolescent↗
PubMed1993

Establishment of conditionally immortalized epithelial cell lines from both colon and small intestine of adult H-2Kb-tsA58 transgenic mice.

Intestinal mucosal cells have proved difficult to culture in vitro. Many attempts have been made to develop long-term cultures of these cells either by direct culturing or by attempting to immortalize these cells by using a range of transforming viral genes, but with little success. The recent development of a transgenic mouse bearing a temperature-sensitive mutation of the simian virus 40 large tumor antigen gene (tsA58) has enabled us to initiate conditionally immortalized cultures of epithelial cells from both small intestinal and colonic mucosa of adult mice. Crypts were isolated from either the small intestines or colons of young adult mice and cultured at the permissive temperature (33 degrees C) in medium containing conditioned medium from a human colon carcinoma cell line, LIM1863. Crypts from both tissues yielded cultures of epithelial cells that have now been in culture for more than 12 months with regular passaging. The epithelial nature of the cells has been confirmed by staining with anti-keratin antibodies. The intestinal origin of the cells was demonstrated by the ability of the cells to synthesize low levels of both brush border peptidases and a disaccharidase. The levels of expression of these enzymes were modulated by the addition of sodium butyrate or phorbol myristate acetate to the medium, which resulted in an increase in the synthesis of the peptidases and a decrease in the synthesis of the disaccharidase. The cells proliferate continuously at the permissive temperature (33 degrees C), but proliferation ceases at the nonpermissive temperature (39.5 degrees C). To our knowledge, this is the first description of the establishment of epithelial cell lines from both small intestine and colon of the same mouse strain. The success reported here indicates that this transgenic mouse will be a useful source of tissue for the study of the mechanisms that control the proliferation and eventual differentiation and senescence of the cells of the intestinal mucosa. These mice will also be a useful source of cells for attempts to culture cells from other tissues that have proved difficult to culture in vitro.

Animals↗
PubMed2004

Effect of food protein supplements on Salmonella enteritidis infection and prevention in laying hens.

Reduction of intestinal colonization of Salmonella enteritidis (SE) during the grow-out period is crucial to provide safer eggs, minimize economic losses, and reduce the spread of human salmonellosis. In the search for novel elimination and prevention methods based on feed supplementation, the effects of feed supplemented with nonimmunized egg yolk powder (did not contain anti-S. enteritidis antibodies), immunized egg yolk powder (with anti-S. enteritidis antibodies), egg yolk proteins, egg white, and skim milk powder were examined on laying hens. In the elimination study, the chickens were orally infected with SE then given a supplemented feed of 5, 10, or 15% (wt/wt) of each of the test samples. Fecal samples tested weekly showed an absence of SE after the first week of feeding nonimmunized egg yolk powder and a gradual decrease with the other samples. In the prevention study, Salmonella-free chickens were fed the supplemented feed for 4 wk and then infected orally. Fecal samples tested for 4 wk showed that SE was prevented from colonizing the intestinal tract throughout the test period by nonimmunized egg yolk powder, whereas the other samples only delayed the colonization. None of the fed supplements disrupted the balance of the intestinal microflora, and the counts in the feces remained constant. These results show that the administration of only 5.0% (wt/wt) of nonimmunized egg yolk powder can eliminate and prevent SE colonization in laying hens with no adverse effects. Furthermore, the present results indicate that hen egg yolk contains novel anti-adhesive or immunomodulatory components that may act to prevent SE infection.

Animals↗
PubMedDate not supplied

Acetylator genotype-dependent expression of arylamine N-acetyltransferase and N-hydroxyarylamine O-acetyltransferase in Syrian inbred hamster intestine and colon. Identity with the hepatic acetylation polymorphism.

Human epidemiological studies suggest an association between rapid acetylator phenotype and the incidence of colorectal cancer. Genetic regulation of acetyl coenzyme A-dependent N-acetyltransferase (NAT) and O-acetyltransferase (OAT) enzymatic activities may play a role in the metabolic activation of arylamine chemicals in the intestine and colon. In this study, the inheritance of acetyltransferase activity in the intestine and colon was investigated in the Syrian inbred hamster model. Relatively high levels of both arylamine NAT and N-hydroxyarylamine OAT activities were expressed in hamster intestine and colon cytosols, at levels similar to those in the liver. Acetylator genotype-dependent levels of NAT activity were expressed towards p-aminobenzoic acid and the carbocyclic arylamine carcinogens 2-aminofluorene (AF), 4-aminobiphenyl, and beta-naphthylamine. However, acetylator genotype-independent activity was found with the heterocyclic arylamine carcinogens 2-aminodipyrido[1,2-a:3',2'd]imidazole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, and 2-amino-9H-pyrido-[2,3,b]indole. F1 hybrid heterozygous acetylator progeny expressed unimodal levels of acetyltransferase activity intermediate between the homozygous rapid and slow acetylator parental strains. F2 generation progeny segregated into three modes (low, intermediate, and high) in a ratio of 1/2/1, and both sets of backcrosses yielded bimodal distributions of low and intermediate or high and intermediate in equal ratios. The genetic data is consistent with simple autosomal Mendelian inheritance of two codominant alleles (rapid and slow) at a single genetic locus, the polymorphic acetyltransferase gene. Levels of N-hydroxy-2-aminofluorene OAT activity were acetylator genotype-dependent in liver, intestine, and colon cytosols, which correlated well with AF NAT activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylation↗
PubMed2005

Characterization of rat small intestinal and colon precision-cut slices as an in vitro system for drug metabolism and induction studies.

The aim of this study was to characterize rat small intestinal and colon tissue slices as a tool to study intestinal metabolism and to investigate gradients of drug metabolism along the intestinal tract as well as drug-induced inhibition and induction of biotransformation. Tissue morphology and the intestinal mucus layer remained intact in small intestinal and colon slices during 3 h of incubation, while alkaline phosphatase was retained and the rate of metabolism of three model compounds (7-hydroxycoumarin, 7-ethoxycoumarin, and testosterone) appeared constant. Phase I and phase II metabolic gradients, decreasing from stomach toward colon were shown to be clearly different for the model compounds used. Furthermore, the observed slice activities were similar or even higher compared with the literature data concerning metabolism of in vitro intestinal systems. Preincubation with beta-naphthoflavone for 24 h induced the O-deethylation of 7-ethoxycoumarin from nearly undetectable to 140 pmol/min/mg protein in small intestine (fresh slices, 43 pmol/min/mg protein) and to 100 pmol/min/mg protein in colon slices (fresh slices, undetectable). Ketoconazole inhibited metabolism of testosterone by 40% and that of 7-ethoxycoumarin by 100%. In conclusion, we showed that the intestinal slice model is an excellent model to study drug metabolism in the intestine in vitro, since we found that the viability parameters remain constant and the measured enzyme activities are relevant, sensitive to inhibitors, and inducible. Therefore, it is a promising tool to study intestinal drug metabolism in human intestine in vitro in the future.

Animals↗
PubMedDate not supplied

[Free perforation of the colon in Crohn's disease].

Free intestinal colonic perforation in Crohn's disease. Free intestinal colonic perforation in Crohn's disease is a serious complication. In reference to the case history of a Crohn patient with sigmoid perforation, a literature survey of free colonic perforations has been given. Only 18 cases of free colonic perforations in Crohn's disease have so far been described in world literature. Pathogenesis, treatment and evolution of this affection have been dealt with.

Adult↗
PubMedDate not supplied

A new technique for preparing precision-cut slices from small intestine and colon for drug biotransformation studies.

INTRODUCTION: A new technique was developed to prepare precision-cut slices from small intestine and colon with the object of studying the biotransformation of drugs in these organs. METHODS: Rat intestinal slices were prepared in two different ways. In the first method, slices were punched out of the small intestine. In the second method, precision-cut slices were made from agarose-filled and -embedded intestines, using the Krumdieck tissue slicer. This method was also applied to colon tissue. Viability of the slices was determined by analysis of intracellular ATP and RNA levels and morphology. Drug metabolizing activity was studied using lidocaine, testosterone, and 7-ethoxycoumarin (7-EC) as phase I substrates, and 7-hydroxycoumarin (7-HC) as a phase II substrate. RESULTS: Precision-cut slices made from agarose-filled and -embedded intestine better preserved ATP levels than tissue that was punched out of the intestinal wall. After 24 h of incubation, morphology in precision cut-slices showed was quite well preserved while punched out tissue was almost completely autolytic after incubation. In addition, total RNA amount and quality was much better maintained in precision-cut slices, when compared to punched out tissue. Both intestinal slices and punched-out tissue showed high, and comparable, phase I and phase II biotransformation activities. DISCUSSION: It is concluded that preparing precision-cut 0.25 mm slices out of agarose-filled and -embedded intestine provides an improvement, compared with punched-out tissue, and that both intestinal and colon slices are useful preparations for in vitro biotransformation studies.

Adenosine Triphosphate↗
PubMed1982

Ultrastructural localization of carcinoembryonic antigen in normal intestine and colon cancer: abnormal distribution of CEA on the surfaces of colon cancer cells.

The distribution of carcinoembryonic antigen (CEA) in normal small intestine, normal colon, and colon cancer of humans was determined immunocytochemically by the peroxidase-labeled antibody method at the light and electron microscopic levels. In the small intestine, CEA was found in protein synthetic organelles, in the mucus, on the microvilli of goblet cells, and on some microvilli of columnar cells adjacent to goblet cells. In the normal colon, CEA was found in protein synthetic organelles of the fully differentiated columnar cells and goblet cells, as well as on the microvilli of the cells. In two well-differentiated colon cancers, the normal preferential surface expression of CEA on the microvilli was maintained, but in six poorly differentiated cancers, CEA was distributed equally over the entire cell surface. We conclude that CEA is a product of goblet cells in the small intestine, columnar and goblet cells in the colon, and colonic cancer cells. CEA on the surfaces of the normal epithelial cells is expressed in a polar manner. This polarity is lacking in undifferentiated neoplastic colon cells, which suggests that failure to establish or maintain the polar expression of normal cell-surface glycoproteins is a characteristic of the neoplastic cells.

Carcinoembryonic Antigen↗
PubMed2004

In vitro adhesion and invasion inhibition of Shigella dysenteriae, Shigella flexneri and Shigella sonnei clinical strains by human milk proteins.

BACKGROUND: Shigella is the etiological agent of shigellosis, a disease responsible for more than 500,000 deaths of children per year, in developing countries. These pathogens colonize the intestinal colon, invade, spreading to the other enterocytes. Breastfeeding plays a very important role in protecting infants from intestinal infections. Amongst milk compounds, glycosylated proteins prevent the adhesion of many enteropathogens in vitro. The aim of this work was to determine the effect of human milk proteins on the colonization potential of Shigella dysenteriae, S. flexneri and S. sonnei. To fulfill this purpose, pooled milk samples from five donors, were fractionated by gel filtration and affinity chromatography. Using tissue culture, the milk fractions obtained were tested in Shigella adhesion and invasion assays. RESULTS: Our revealed showed that both adhesion and invasion of Shigella species were inhibited by low concentration of secretory immunoglobulin A, lactoferrin and free secretory component. This work also showed that, these proteins bind to superficial and whole-cell Shigella proteins. CONCLUSIONS: Our findings suggest that human milk may act inhibiting adhesion and, consequently, invasion of Shigella, thereafter preventing shigellosis in infants.

Antibodies, Bacterial↗
PubMed1986

Sulphomucin colonic type intestinal metaplasia and carcinoma in the stomach. A histochemical study of 115 cases obtained by biopsy.

One hundred fifteen gastroscopic biopsy specimens (54 cases of carcinoma and 61 of gastritis) were used in this histochemical study. Intestinal metaplasia (IM) was classified into small intestinal type (ST) and colonic type (CT). The former may be a reactive change only. The incidence of sulphomucin colonic type (SCT) metaplasia was higher in gastric carcinomas than in benign lesions (P less than 0.01), and a relation between SCT metaplasia and cancer was demonstrated by both histologic and histochemical procedures. This suggests that SCT IM is correlated with certain precancerous lesions. There was no significant difference in the incidence of O-acetyl sialomucin colonic type (OCT) metaplasia between benign and malignant diseases. Further study is needed to determine why slightly more than half of the SCT IM was accompanied by OCT IM.

Biopsy↗
PubMed1995

Crypt fission in the small intestine and colon. A mechanism for the emergence of G6PD locus-mutated crypts after treatment with mutagens.

In the small intestine and colon, administration of mutagens leads to the emergence of crypts populated by cells with a different, mutated phenotype. This is preceded by a transient rise in the frequency of crypts with a partially mutated phenotype, and the disappearance of these partially mutated crypts occurs contemporaneously with the attainment of a plateau value of the wholly mutated crypts. Here, using the mutagen ethyl nitrosourea and loss of glucose-6-phosphate dehydrogenase staining as a marker, we show that the plateau is reached at between 4.6 and 7 weeks in the colon and at 12 weeks in the small intestine of the same mice. Explanations for this difference have included differences in the stem cell cycle time of a single "master" stem cell or multiple stem cells occupying a stem cell "niche" with random loss after stem cell division. However, we demonstrate that the crypt fission index, or the incidence of crypts in fission, is some four times higher in the colon than in the small intestine at the time of ethyl nitrosourea injection, and propose an alternative hypothesis based on crypt fission as the mechanism for the more rapid evolution of wholly mutated crypts in the colon. The hypothesis should enable us to predict the results of future experiments, namely that the emergence of wholly mutated crypts is proportional to the crypt fission index.

Animals↗
PubMed2004

Prediction of whole-body metabolic clearance of drugs through the combined use of slices from rat liver, lung, kidney, small intestine and colon.

1: The aim was to investigate whether precision-cut rat tissue slices could be used to predict metabolic drug clearance in vivo. To obtain a complete picture, slices not only from liver, but also from lung, kidney, small intestine and colon were included. 2: The metabolic clearances of 7-ethoxycoumarin, 7-hydroxycoumarin, testosterone, methyltestosterone and warfarin were determined by measuring the disappearance of these compounds during incubation with slices prepared from liver, lung, kidney, small intestine and colon. 3: The total in vitro metabolic clearance was determined by adding the individual in vitro organ clearances from the slices. Prediction based on the in vitro clearance was within an order of magnitude to the corresponding in vivo values. Interestingly, the relative contribution of extrahepatic metabolic clearance of the studied compounds to total clearance was remarkably high, ranging from 35 to 72% of the total metabolic clearance. 4: It is concluded that the model of multi-organ precision-cut slices is a useful in vitro tool for prediction of in vivo metabolic clearance. In addition, it provides information about the relative contribution of the liver, lung, kidney, small intestine and colon to the total metabolic clearance.

Animals↗
PubMed1987

Pathology of neuromuscular disorders of the small intestine and colon.

A variety of pathological abnormalities of the smooth muscle and myenteric plexus result in clinical syndromes of disordered small intestinal and colonic motility. These pathological abnormalities have been noted by conventional light microscopy and by utilization of Smith's technique for visualizing the myenteric plexus with silver. We have classified the neuromuscular disorders into two major categories, i.e., those affecting the myenteric plexus and those affecting the smooth muscle. The classification is further developed based on the variety of clinicopathological features of the various disorders. Although we can now identify the underlying pathology of these motor disorders and thus understand these illnesses better than we did a decade ago, we have much more to learn. With the great strides being made to understand the normal structure, function, and development of the myenteric plexus and smooth muscle, there is hope that we will be able to learn much more about the etiology and pathogenesis of these neuromuscular disorders in the decade to come.

Colon↗
PubMed1995

Malnutrition in the developing and developed world: is small intestinal bacterial colonization important?

Malnutrition is a major problem on a global basis and will continue if current world population trends persist. Small intestinal bacterial colonization may contribute to malnutrition in populations whose dietary intake is marginal, such as those in developing countries and many elderly in the developed world. This review focuses on the evidence for small intestinal bacterial colonization in these subjects and briefly revises current thinking on the pathogenesis and diagnosis of this condition.

Bacteria↗
PubMedDate not supplied

[Clinical and epidemiologic analysis of intestinal tract colonization with vancomycin-resistant enterococci in an intensive care unit].

Intestinal tract colonization with vancomycin resistant enterococci (VRE) was studied during five months and 25 days. Out of 171 patients hospitalized in the intensive care unit, 124 (73%) were included in this study. Thirty five of them (28%) were recognized as colonized with VRE. VRE isolates (n = 35) were identified as Enterococcus faecium (n = 18), Enterococcus gallinarum (n = 16), and Enterococcus raffinosus (n = 1). All of them were resistant to vancomycin (MIC90 = 512 microg/ml) and to teicoplanin (MIC90 = 32 microg/ml), having the vanA gene. By means of molecular methods a high homology was found among E. faecium and E. gallinarum isolates, respectively, suggesting their spread as a kind of outbreak. No significant differences in age or sex were found among colonized and non-colonized patients (p > 0.05). On the other hand, the hospitalization time and the use of broad-spectrum antibiotics were associated with colonization. From this study we highlight the importance of enhancing all measures of control and prevention of hospital infections, carefully analyzing the empiric antimicrobial schemes, trying to reduce the hospital stage, and following the surveillance to evaluate the efficacy of such procedures.

Adolescent↗
PubMed1998

Identification and distribution of mRNA encoding the Y1, Y2, Y4, and Y5 receptors for peptides of the PP-fold family in the rat intestine and colon.

Peptide YY (PYY), neuropeptide Y (NPY) and pancreatic polypeptide (PP) are structurally related peptides which have potent antisecretory effects in small and/or large intestines. Receptors mediating these effects are still unknown with the exception of a PYY-preferring receptor expressed in small intestinal crypts. In the present study, expression of recently cloned Y1, Y2, and Y5 receptors which have similar affinity for PYY and NPY and Y4 receptors which have a high affinity for PP was investigated in gut by RT-PCR analysis. The data show that all Y receptors are expressed in small intestine and/or colon but with specific distributions. Y1 receptors are only expressed in nonepithelial colonic tissue, whereas Y2 and Y4 receptors are present in both epithelial and nonepithelial tissue of the small or large intestine. In contrast, Y5 receptor expression appears to be restricted to epithelial crypts of the small intestine and nonepithelial tissue of colon. Sequencing of PCR products showed 100% identity with the corresponding sequences of the cloned Y1, Y4, or Y5 receptors. The PCR product obtained with Y2 primers from rat crypt cells showed 84% identity with the cloned human Y2 receptor. These data indicate a wide distribution of Y receptors in small intestine and colon. They also suggest that Y1, Y2, Y4, and Y5 receptors may be responsible for still unexplained effects of PYY, NPY, or PP on secretion in small and large intestines.

Animals↗