Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “colonization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 505 records · Page 28Linked to original sources
PubMed2000

Evaluation of uniformity of morphological injury of the large colon following severe colonic torsion.

This report describes the evaluation of uniformity of morphological injury of the large colon following severe colonic torsion in 17 horses presented to the Veterinary Medical Teaching Hospital. In 16 horses, twist occurred at the colonic base and in 1 at the sternal and diaphragmatic flexure. Eleven of the 17 horses were subjected to euthanasia at surgery and 6 of 17 following surgical correction within 4 days postoperatively. The objective of this study was to determine if the degree of histological changes present at the pelvic flexure were uniformly distributed throughout the regions of the colon involved in cases of severe colonic torsion.

Animals↗
PubMed1993

Inter-relationships between inflammatory mediators released from colonic mucosa in ulcerative colitis and their effects on colonic secretion.

Metabolites of arachidonic acid have been implicated in the pathophysiology of ulcerative colitis-they can stimulate intestinal secretion, increase mucosal blood flow, and influence smooth muscle activity. The influence on the mucosal transport function of culture medium in which colonic mucosal biopsy specimens had been incubated was investigated using rat stripped distal colonic mucosa in vitro as the assay system. Colonic tissue from patients with colitis and from control subjects was cultured. Medium from inflamed tissue contained more prostaglandin E2 (PGE2) and leukotriene D4 (LTD4) and evoked a greater electrical (secretory) response in rat colonic mucosa than control tissue medium. In inflamed tissue, cyclo-oxygenase inhibition (indomethacin) attenuated PGE2 but increased LTD4 production; conversely lipoxygenase inhibition (ICI 207968) inhibited LTD4 production but enhanced PGE2 output. Each inhibitor alone enhanced the electrical response in the rat colon. Inhibition of both enzymes (indomethacin plus ICI 207968) caused a fall in both PGE2 (82%) and LTD4 (89%) production and in the electrical response (57%). Inflamed tissue treated with a phospholipase A2 inhibitor (mepacrine) produced less PGE2, LTD4, and electrical responses when compared with inflamed tissue, either untreated (91%, 92%, and 79% respectively) or treated with cyclo-oxygenase and lipoxygenase inhibition. Incubation with bradykinin stimulated eicosanoid release and electrical response, while a bradykinin antagonist caused a modest inhibition. Analysis of these observations suggests that a combination of arachidonic acid derivatives accounts for about half the secretory response. Other products of phospholipase A2 activity are probably responsible for much of the remainder, leaving up to 20% the result of types of mediator not determined in this study.

Adult↗
PubMed1999

Detection of anti-colon antibodies in inflammatory bowel disease using human cultured colonic cells.

BACKGROUND: Investigation of anti-colon antibodies may be simplified if a sensitive method and homogeneous source of antigen were available. AIMS: To examine the anti-colon antibody response using human colonic carcinoma cell lines as antigen. SUBJECTS: Patients with inflammatory bowel disease and other gastrointestinal disorders and healthy controls were studied. METHODS: Comparative enzyme linked immunosorbent assays (ELISAs) were performed to assess the value of whole Caco-2, HT-29, and LS-180 cells as antigen. The antigenic determinants of the immune response were characterised by western blot analysis. RESULTS: Sera demonstrated immunoreactivity against each of the cell lines, but different epitopes were recognised. Applying whole Caco-2 cells as antigen in an ELISA, the prevalence of anti-colon antibodies was significantly greater in patients with ulcerative colitis (36%) than Crohn's disease (13%), other gastrointestinal disorders (13%) and healthy controls (0) (p<0. 05). The immune response was not associated with one predominant antigen. CONCLUSIONS: Fixed whole cell ELISA is a simple and feasible method for studying the anti-colon antibody response. This response is non-specific, being directed against multiple antigens, and is likely to be an epiphenomenon of inflammatory bowel disease, more so for ulcerative colitis than Crohn's disease.

Adolescent↗
PubMed2002

Physiology of sulfide in the rat colon: use of bismuth to assess colonic sulfide production.

Colonic bacteria produce hydrogen sulfide, a toxic compound postulated to play a pathogenetic role in ulcerative colitis. Colonic sulfide exposure has previously been assessed via measurements of fecal sulfide concentration. However, we found that <1% of fecal sulfide of rats was free, the remainder being bound in soluble and insoluble complexes. Thus fecal sulfide concentrations may reflect sulfide binding capacity rather than the toxic potential of feces. We utilized bismuth subnitrate to quantitate intracolonic sulfide release based on observations that bismuth 1) avidly binds sulfide; 2) quantitatively releases bound sulfide when acidified; and 3) does not influence fecal sulfide production by fecal homogenates. Rats ingesting bismuth subnitrate excreted 350 +/- 18 micromol/day of fecal sulfide compared with 9 +/- 1 micromol/day in control rats. Thus the colon normally absorbs approximately 340 micromol of sulfide daily, a quantity that would produce local and systemic injury if not efficiently detoxified by the colonic mucosa. Studies utilizing bismuth should help to clarify the factors influencing sulfide production in the human colon.

Animal Feed↗
PubMed1990

The influence of colonizing micro-organisms on development of crypt architecture in the neonatal mouse colon.

The effects of the normal colonizing microflora on postnatal development in the infant mouse were determined by comparison of crypt parameters in histological sections of the ascending colons of conventional specified-pathogen-free mice and their germ-free counterparts. Association of bacteria with the developing colonic mucosa in the third postnatal week caused a lengthening of the crypt column and depressed the total number of secreting goblet cells in each crypt. Thus the increasing bacterial burden during colonization of the developing colon was associated not only with expansion of the proliferative component of the crypt but also with modulation of the relative proportions of crypt cell populations.

Animals↗
PubMed1991

Long-term explant culture of human colon and a 3-step transformation model for rat colonic epithelium.

Our previous studies have suggested that colonic epithelium from rodents pretreated in vivo with suboptimal doses of carcinogen could be more easily maintained in explant culture. Transformation of colonic epithelium from these explants may be induced by subsequent exposure to additional genotropic agents. Therefore, we describe the development of a 3-step transformation model which uses (1) in vivo pretreatment with a suboptimal dose of 1,2-dimethylhydrazine (DMH) followed by (2) in vitro organ culture and exposure to xenotropic murine sarcoma virus (X-MSV), and finally (3) xenograft maintenance in nude mice to allow sufficient time for transformation. Male Wistar rats were injected intramuscularly with 20 mg DMH/kg 10 times per week followed by the removal and explant culture of the colon, which was then treated in vitro with X-MSV, and transplanted into nude mice after 1 week of culture. All the nude mice (n = 6) transplanted with rat colon explants contained viable xenograft explant epithelium and 1 of the 6 showed transformation. Our results demonstrate that the epithelium from animals pretreated with suboptimal doses of carcinogens can be easily transformed. We also demonstrate that human colonic epithelium is viable for an extended period of time in this model. Based on these results, we hypothesize that such a 3-step transformation model is applicable for carcinogenesis studies of various organs from different species, including human if one uses dysplastic or 'pre-neoplastic initiated' tissues obtained at surgery (e.g., ulcerative colitis; Barret's esophagus, etc.).

Animals↗
PubMed2000

In vitro investigation of the effect of prostaglandins and nonsteroidal anti-inflammatory drugs on contractile activity of the equine smooth muscle of the dorsal colon, ventral colon, and pelvic flexure.

OBJECTIVES: To determine the in vitro effect of prostaglandin E2 (PGE2), PGF2alpha, PGI2; and nonsteroidal anti-inflammatory drugs (NSAID; ie, flunixin meglumine, ketoprofen, carprofen, and phenylbutazone) on contractile activity of the equine dorsal colon, ventral colon, and pelvic flexure circular and longitudinal smooth muscle. ANIMALS: 26 healthy horses. PROCEDURE: Tissue collected from the ventral colon, dorsal colon, and pelvic flexure was cut into strips and mounted in a tissue bath system where contractile strength was determined. Incremental doses of PGE2, PGF2alpha,, PGI2, flunixin meglumine, carprofen, ketoprofen, and phenylbutazone were added to the baths, and the contractile activity was recorded for each location and orientation of smooth muscle. RESULTS: In substance P-stimulated tissues, PGE2 and PGF2alpha enhanced contractility in the longitudinal smooth muscle with a decrease or no effect on circular smooth muscle activity. Prostaglandin I2 inhibited the circular smooth muscle response with no effect on the longitudinal muscle. The activity of NSAID was predominantly inhibitory regardless of location or muscle orientation. CONCLUSIONS AND CLINICAL RELEVANCE: In the equine large intestine, exogenous prostaglandins had a variable effect on contractile activity, depending on the location in the colon and orientation of the smooth muscle. The administration of NSAID inhibited contractility, with flunixin meglumine generally inducing the most profound inhibition relative to the other NSAID evaluated in substance P-stimulated smooth muscle of the large intestine. The results of this study indicate that prolonged use of NSAID may potentially predispose horses to develop gastrointestinal tract stasis and subsequent impaction.

Animals↗
PubMedDate not supplied

Intraoperative colonic lavage with primary anastomosis vs. Hartmann's procedure for perforated diverticular disease of the colon: a consecutive study.

BACKGROUND/AIMS: The ideal treatment for complicated diverticulitis is still controversial. The Hartmann's procedure remains the favored option in patients with acute complicated sigmoid disease but there has been increasing interest in primary resection and anastomosis with intraoperative colonic lavage. A prospective study was carried out on 71 patients with peritonitis, comparing primary resection with intraoperative colonic lavage, and Hartmann's procedure. METHODOLOGY: Between January 1994 and September 1999, 71 patients underwent emergency laparotomy for diverticular peritonitis. Primary resection and anastomosis with intraoperative colonic lavage was performed in 29 patients (group I) and Hartmann's procedure in 42 patients (group II). All data were collected on standardized forms. RESULTS: There were no differences between the two groups according to clinical features, biology, severity of disease and operative delay. The mortality rate in group I and group II was, respectively, 7 and 10% (P = 0.6). The incidence of postoperative complication was higher after Hartmann's procedure (P < 0.05). The mean hospital stay was significantly longer for the Hartmann's procedure compared to primary resection with intraoperative colonic lavage. CONCLUSIONS: Primary resection with intraoperative colonic lavage compares favorably with Hartmann's procedure for local or diffuse purulent peritonitis in complicated diverticulitis. It should be an alternative to the Hartmann's procedure in stercoral peritonitis.

Adult↗
PubMed2003

Colonic pseudo-obstruction: the dilated colon in the ICU.

Acute colonic pseudo-obstruction is a syndrome of massive dilation of the colon without mechanical obstruction that develops in hospitalized patients with serious underlying medical and surgical conditions. Increasing age, cecal diameter, delay in decompression, and status of the bowel significantly influence mortality, which is approximately 40% when ischemia or perforation is present. Evaluation of the markedly distended colon in the intensive care unit setting involves excluding mechanical obstruction and other causes of toxic megacolon such as Clostridium difficile infection, and assessing for signs of ischemia and perforation. The risk of colonic perforation in acute colonic pseudo-obstruction increases when cecal diameter exceeds 12 cm and when the distention has been present for greater than 6 days. Appropriate management includes supportive therapy and selective use of neostigmine and colonoscopy for decompression. Early recognition and management are critical in minimizing complications.

Acute Disease↗
PubMed2003

Cytochrome P450 1B1 (CYP1B1) is overexpressed in human colon adenocarcinomas relative to normal colon: implications for drug development.

The cytochrome P450 family of enzymes is involved in the Phase I metabolism of a wide variety of compounds. Although generally involved with detoxification, overexpression of one family member, cytochrome P450 1B1 (CYP1B1), has been associated with human epithelial tumors. As such, CYP1B1 was hypothesized to be a novel target for the development of anticancer therapies. We investigated expression of CYP1B1 protein in 61 human colorectal adenocarcinomas and compared this to that observed in 14 histologically normal human large bowel samples removed from patients undergoing surgery for large bowel tumors. Although we confirmed that CYP1B1 was expressed at high levels in human colorectal tumor epithelia, we also found that CYP1B1 was not absent from normal colonic epithelia but was expressed at low levels. The expression of CYP1B1 in colon tumors does not correlate with tumor stage or degree of lymph node invasion in this study. Furthermore, in addition to expression in colon epithelia, CYP1B1 is also observed in blood vessels within the colon. As with the epithelia, levels of CYP1B1 were higher in tumor vasculature than that of the normal colon. Although these observations greatly support the development of CYP1B1 targeted anticancer therapies, they also indicate the caution that should be observed when developing such drugs.

Adenocarcinoma↗
PubMed1990

Morphology of the transplantable colon carcinoma derived from the spontaneous colon carcinoma of WF-Osaka rat strain.

Two lines of the transplantable colon carcinoma were established. They were from the spontaneous colon carcinoma of WF-Osaka rat strain which had been set up in our laboratory. Transplant procedure was carried out mainly by the intraperitoneal implantation, and, in particular, the treating with a specified way of HIBITANE for disinfection against colonic flora at the primary transplant was quite effective. The growth speed of the transplanted colon carcinoma was slow at first and gradually increased its speed. Histology of the transplanted tumor altered gradually from the glandular pattern at first to the medullary pattern in the late stage of the transplant generation. Each tumor node in the late stage of transplant generation was composed of numerous small nodules separated by thin stromal tissue. Squamous metaplasia and central necrosis were seen in the center of the small nodules. Two lines of the transplantable colon carcinoma were named C1 and C2 and the former is at now the 101th generation and the latter is at the 107th generation.

Animals↗
PubMed1992

[Perioperative morbidity and mortality of colon resection in colonic carcinoma].

An analysis of the local and systemic perioperative complications is conducted to explore the risk of resection of colon cancer. In a retrospective study we analyzed 231 consecutive patients operated on between 1984 and 1988. The mean age was 70 (37-91) years. The operations consisted in 3 ileocecal resections, 144 right hemicolectomies, 10 resections of the transverse colon, 22 left hemicolectomies, 77 resections of the sigmoid colon and 5 subtotal colonic resections. 2 patients (0.9%) had a clinical leakage of the anastomosis. 3 patients were reoperated: one because of anastomotic leakage and two because of ileus due to small bowel adhesions. 2 patients with uncomplicated local healing died within 30 days after the operation from systemic complications (mortality 0.9%). It is concluded that with standardized preoperative bowel preparation, prophylactic perioperative antibiotics and modern anesthesia, the resection of colon cancer is today possible with minimal perioperative risk.

Adult↗
PubMed1991

Increased number of accessible sugar epitopes defined with monoclonal antibody AM-3 on colonic mucins is associated with malignant transformation of colonic mucosa.

Monoclonal antibody AM-3 detects a mucin sugar epitope (AM-3 epitope) the expression of which increases in the course of human colon carcinogenesis parallel to the gradual morphological alterations (so called adenoma-carcinoma sequence). In the present report the AM-3-positive mucin has been purified from human normal and carcinomatous colonic tissue. About 300-fold enrichment of the epitope per protein from both sources was achieved after ultracentrifugation, gel filtration on Sepharose CL-6B and isopyknic gradient centrifugation. Slot-blot and enzyme-linked immunosorbent assays of the purified preparation indicated not only different amounts of the mucins but also a consistent qualitative difference between the molecules from both sources. The qualitative difference could be obliterated by a partial removal of the AM-3 epitope from the tumor-derived mucin with neuraminidase. The visualization of the molecules by rotary shadowing indicated that the mucins from both sources have similar length distribution, 80% of the molecules being 100-600 nm long. The reaction with AM-3 antibody followed by rotary shadowing showed that in the purified preparations more than 95% of the tumor-derived molecules and 74% of the normal colon tissue-derived molecules carried the epitope. The tumor-derived mucins bound, on the average, 34 +/- 15 (SD) antibodies/1000 nm of the protein core while the mucin from normal colon tissue carried 12 +/- 11 antibodies/1000 nm of the protein core. These data indicate that the increased expression of AM-3 epitopes during malignant transformation of the human colon is due to accumulation of AM-3-positive mucin as well as a higher number of accessible AM-3 epitopes on this mucin.

Antibodies, Monoclonal↗
PubMed1991

[Short-term assay of colon carcinogen--induction of micronuclei and apoptosis by dimethylhydrazine in the mouse colon crypt cells].

The frequencies of micronuclei and apoptosis in the colon crypt cells of mice treated with colon carcinogen were studied. Two strains of mice, inbred C57BL and close colony Kun-ming mice were used in this experiment. The mice were killed at 24 hr after intraperitoneal injection of dimethylhydrazine (DMH) at doses of 10, 20 and 40 mg/kg body weight. The results indicated that the frequencies of micronuclei and apoptosis in the colon crypt cells of both C57BL and Kun-ming mice were positively correlated quantitatively with the doses of DMH. Our results are similar to that of Heddle obtained in C57BL mice. We propose that the assay of micronuclei and apoptosis in mouse colon crypt cells might be a rapid and sensitive test and useful as a screening method for potential colon carcinogens. Kun-ming mice may be used as the test animal for detecting nuclear anomalies in this assay in lieu of C57BL mice.

Animals↗
PubMed1990

[Irritable colon and colonic disease due to laxatives].

Diarrhea of colonic origin is fairly common in irritable colon and after long term abuse of laxatives. This form of diarrhea causes difficulties not only in diagnosis but also in treatment. Irritable colon is a functional disorder sometimes involving other segments of the bowel. The term "irritable bowel disease" is thus more appropriate. Extraintestinal symptoms are in addition quite common. Although the diagnosis can be established with great reliability using an index we consider some laboratory tests, recto-sigmoidoscopy and abdominal sonography essential to rule out organic lesions. Therapy comprises (small) psychotherapy, dietary measures and eventually transient medication. Symptoms usually persist but tolerance of the disorder should be improved. Laxative-induced colonic dysfunction results usually from false assumptions about normal defecation. Loss of water and potassium deteriorates the symptomatology leading to a vicious circle. Alterations of neurons in the enteric nervous system of the colon can be the cause but eventually the consequence of chronic intake of laxatives. Hidden abuse of laxatives can cause great diagnostic difficulties. The therapy of choice is weaning which usually is only possible gradually. Cisapride can be a useful adjuvant.

Cathartics↗
PubMed1986

[Clinico-genetical studies of colonic cancer. II. Genetic analysis of predisposition to colonic cancer].

The structure of subjection to different clinical forms of colon cancer and to the morbidity as a whole approximates better the quasi-continued phenotypical model within which the contribution of genetic factors reaches 68-84%, that of incidental medium factors being 16-32%. Genetic study of heterogeneity of colon cancer clinical forms revealed that their pathogenetic community was quite high. However, the origin of colon cancer depends strongly on genetic factors (83.7 +/- 7.3%), in comparison with rectal cancer (67.9 +/- 7.1%). The analysis of colon cancer interrelation with other malignant neoplasms (including specific ones for women--breast and uterus cancer) revealed that the development of another malignant neoplasms was the result of the influence of partially common genes (20-50%) which predetermined the development of colon cancer and other malignant neoplasms. According to the data obtained in this study, the tables of repeated risk have been worked out which may be used for medico-genetic consultation.

Adult↗
PubMed1980

Tight junctions in epithelial cells of human fetal hindgut, normal colon, and colon adenocarcinoma.

The structural patterns of tight junctions in normal human colon mucosa, colon adenocarcinomas, and fetal colon were studied and compared by the freeze-fracturing technique. The zonula occludens of the normal colon cells at the upper, more differentiated part of the crypts of Lieberkühn appeared as continuous belts made of about eight parallel strands. At the less differentiated bases of the crypts, the zonula occludens was less regular and contained fewer, mostly beaded strands. In the colons of 10-week fetuses, early stages of tight junction assembly were observed. At the same time, vesicles bearing remnants of tight junction elements were observed within the cytoplasm. This finding suggested that during the early development and organization of the fetal gut, mechanisms of assembly and disassembly of tight junctions are operating concomitantly. In well-differentiated adenocarcinomas, the cells in the luminal region retained their polarity and had seven or eight parallel junctional elements. In infiltrating cells, however, tight junctions appeared as fascia occludens and resembled the junctional organization of 10-week fetuses.

Adenocarcinoma↗
PubMed1995

The laminin alpha 1 chain Ile-Lys-Val-Ala-Val (IKVAV)-containing peptide promotes liver colonization by human colon cancer cells.

Laminin, a major basement membrane-specific glycoprotein, promotes the attachment, migration, and invasion of a variety of tumor cells. Since laminin is present in the perisinusoidal matrix of the liver, we studied its effects on liver colonization by human colon cancer cells (HM7, LiM6) previously shown to have liver-metastasizing ability in athymic mice. These malignant cells expressed high levels of a 32-kDa laminin-binding protein on Western blot analysis when compared to the low metastatic parental cell line. Coinjection of laminin alpha chain-derived peptides which contain the amino acid sequence Ile-Lys-Val-Ala-Val (IKVAV) significantly stimulated liver colonization as determined by liver weight (P < 0.005) and number of tumor nodules (P < 0.02) 3 weeks after splenic-portal inoculation into nude mice. No stimulation was seen with a control peptide containing the same amino acids but in a scrambled sequence. In contrast, the Tyr-Ile-Gly-Ser-Arg peptide from the laminin beta 1 chain significantly inhibited HM7 liver colonization. These differences were not due to alterations in the number of cells initially reaching the liver as determined by injection of [125I]iododeoxyuridine-labeled tumor cells, but retention in the liver was stimulated by the IKVAV-containing peptides. Flow analysis indicated that the IKVAV peptide may act, in part, by stimulating homotypic adhesion of tumor cells. These data suggest that interactions of colon cancer cells with the IKVAV site on laminin may play a role in the formation of metastatic foci in the liver through cell-cell or cell-substratum interactions which promote metastasis.

Adenocarcinoma↗