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Role of inducible nitric oxide synthase in trinitrobenzene sulphonic acid induced colitis in mice.

BACKGROUND: Studies using inhibitors of nitric oxide synthase (NOS) to date are inconclusive regarding the role of inducible NOS (iNOS) in intestinal inflammation. AIMS: (1) To examine the role of iNOS in the development of chronic intestinal inflammation; (2) to identify the cellular source(s) of iNOS. METHODS: Colitis was induced by an intrarectal instillation of trinitrobenzene sulphonic acid (TNBS, 60 mg/ml, 30% ethanol), in wild type (control) or iNOS deficient mice. Mice were studied over 14 days; the colons were scored for injury and granulocyte infiltration was quantified. Blood to lumen leakage of (51)Cr-EDTA was measured as a quantitative index of mucosal damage. RESULTS: At 24 and 72 hours, iNOS deficient mice had significantly increased macroscopic inflammation compared with wild type mice. Granulocyte infiltration increased significantly at 24 hours and remained elevated in iNOS deficient mice at 72 hours, but significantly decreased in controls. However, by seven days post-TNBS macroscopic damage, microscopic histology, granulocyte infiltration, and mucosal permeability did not differ between wild type and iNOS deficient mice. A four- to fivefold increase in iNOS mRNA was observed in wild type mice at 72 hours and seven days post-TNBS and was absent in iNOS deficient mice. Immunohistochemistry techniques showed that iNOS expression was predominantly localised in neutrophils, with some staining also in macrophages. CONCLUSIONS: These results suggest that leucocyte derived iNOS ameliorates the early phase, but does not impact on the chronic phase of TNBS induced colitis despite the presence of iNOS.

Acute Disease↗

Oral mesalamine and clinical remission are associated with a decrease in the extent of long-standing ulcerative colitis.

OBJECTIVE: To compare colonoscopy alone with surveillance biopsy for the determination of anatomic extent in long-standing ulcerative colitis (UC). To assess the influences of mesalamine use and clinical disease activity on the change of histologic extent with time. MATERIALS AND METHODS: Disease extent (proctosigmoiditis, left-sided colitis, or pancolitis) measured by colonoscopy and surveillance biopsy was compared among 212 consecutive patients with long-standing UC. Among the 102 patients who had 2 consecutive colonoscopies with surveillance biopsies, the following influences on change in histologic extent were determined: disease activity, mesalamine use, age at disease onset, folic acid, corticosteroid and azathioprine/6-mercaptopurine use, and time between colonoscopies. RESULTS: Agreement between gross and microscopic findings was poor (kappa = 0.39). Colonoscopy underestimated and overestimated extent in 25.9% and 8.5%, respectively. Microscopic distribution between consecutive colonoscopies remained the same in 60.8%. Where distribution changed, an increase was twice as common as a decrease in extent. There was no difference in age at onset, time between colonoscopies, or disease duration among those with an increase, decrease, or no change in extent. Clinical remission and oral mesalamine were independently associated with 10.7 and 5.8 times the odds of a decrease in disease extent, respectively. Folic acid, topical mesalamine, corticosteroids, and immunomodulators did not influence change in extent. CONCLUSIONS: UC extent is best determined by surveillance biopsy. Among patients with long-standing UC, histologic extent fluctuates with time. Disease remission and oral mesalamine were independently associated with decreases in disease extent.

Administration, Oral↗

In vitro effects of dextran sulfate sodium on a Caco-2 cell line and plausible mechanisms for dextran sulfate sodium-induced colitis.

Pathogenic mechanisms responsible for inflammatory bowel disease (IBD) are poorly understood. In an IBD animal model, the oral administration of polysaccharides such as dextran sulfate sodium (DSS) induces colitis, which exhibit several clinical and histological features for IBD. However, pathogenic factors in the development of colitis remain unclear. Therefore, we investigated possible mechanisms for DSS-induced colitis, and mainly focused on biological responses from an intestinal epithelial cell line, Caco-2. Cytotoxicity and cytokine release were measured using MTS assays and ELISA, respectively. The effect of DSS on the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers was also evaluated. Cell cycle progression was estimated using antibodies directed against p53 and cdc-2 proteins. The generation of reactive oxygen species (ROS) was measured using a DCFH-DA method. Pyridylamino-DSS (PA-DSS) was used as a fluorometric label in order to investigate fluorescence-microscopically the location of DSS in Caco-2 cells. DSS induced cytotoxicity on Caco-2 cells at 5%. DSS also induced strong TEER decrease at 3%. DSS induced the weak release of IL-8, IL-6, and TGF-beta1. Remarkably DSS arrested Caco-2 cell cycle and reduced the intracellular generation of ROS. Under fluorescence microscopy, PA-DSS entered cells and bound to the nucleus, indicating this binding of DSS may be involved in the cell cycle arrest of Caco-2 cells. The cell cycle arrest and reduced intracellular generation of ROS may be involved during initiation or throughout the early stages of DSS-induced colitis.

Caco-2 Cells↗

Activation of the mucosal immune system in irritable bowel syndrome.

BACKGROUND & AIMS: A role for the mucosal immune system in the pathogenesis of irritable bowel syndrome is suggested by its association with intestinal infections. METHODS: To investigate this, we performed histologic and immunohistologic studies on colonoscopic biopsy specimens from 77 patients with symptoms satisfying the Rome criteria and 28 asymptomatic control patients. RESULTS: Histologic assessment of biopsy specimens from symptomatic patients indicated 3 different groups. The first (38 of 77) had normal conventional histology; however, immunohistology showed increased intraepithelial lymphocytes (median, 1.8-fold; range, 1.74-1.86), lamina propria CD3(+) cells (2-fold; range, 1.55-2.91), and CD25(+) cells (6.5-fold; range, 4.98-8.13) compared with asymptomatic controls. The second group (31 of 77) had nonspecific microscopic inflammation and on immunohistology showed similar increases in lymphocyte populations (not significant vs. the uninflamed group) as well as increased numbers of neutrophil leukocytes and mast cells (P < 0.0001 vs. controls and the uninflamed group). The third group (8 of 77) fulfilled histologic and immunohistologic criteria for classic lymphocytic colitis. CONCLUSIONS: Examination of colonoscopic biopsy specimens from patients meeting the Rome criteria for a clinical diagnosis of irritable bowel syndrome showed subgroups with normal and abnormal conventional histology. All groups showed increased numbers of activated immunocompetent cells in the intestinal mucosa on quantitative immunohistology, implicating the mucosal immune system in pathogenesis.

Adult↗

Acute onset of ulcerative colitis following an operation for sigmoid colon cancer.

We describe a case of ulcerative colitis (UC) where clinical symptoms began abruptly within a few weeks after colon resection. The patient, a 44-year-old woman, was first referred to our hospital for the treatment of colon cancer. During the past several years, she had not had any inflammatory bowel disease-like clinical symptoms, such as frequent diarrhea or abdominal discomfort. Before the operation, both macroscopic and microscopic examination revealed that no remarkable inflammatory change was associated with the cancer in any area of her colon. At 10 days after the operation, she started to complain of frequent watery diarrhea. Two weeks after the operation, she was readmitted to our hospital because of frequent bloody diarrhea, fever, and abdominal discomfort. Based on endoscopic and histological examinations, she was diagnosed as having severe UC and was treated with hyperalimentation, predonisolone, mesalazine, and granulocyte apheresis. However, she did not respond to this combination therapy. At 45 days after the first operation, owing to sudden onset hemorrhagic shock, she underwent a second colectomy. The resected specimen of the entire colon showed severe pancolitis, and histological examination revealed severe inflammatory changes in the lamina propria together with crypt distortion, all of which were consistent with UC.

Acute Disease↗

[Experimental study on influence of acupuncture and moxibustion therapy on apoptosis of colonic epithelial cells in rats of ulcerative colitis].

OBJECTIVE: To study the mechanism of acupuncture and moxibustion in adjusting apoptosis of colonic epithelial cells of the rat of ulcerative colitis (UC). METHODS: UC rats were randomly divided into four groups including normal control group (NC), model control group (MC), herbs-partitioned moxibustion group (HPM) and electroacupuncture group (EA). The HPM and EA groups were respectively treated with herbs-partitioned moxibustion and electroacupuncture at "Qihai" (CV 6) and bilateral "Tianshu" (ST 25). Then the colon of the rat was taken and the changes of the tissue structure and the cell apoptosis were observed by electron microscope and flow cytometer respectively. RESULTS: The colon tissue showed histopathological changes, and apoptosis of epithelial cells increased in the model mice of UC as compared with the normal rat. Electroacupuncture and drug-separated moxibustion could significantly decrease the abnormal apoptosis of epithelial cells. CONCLUSION: The adjustment of the abnormal apoptosis of epithelial cells is one of the mechanisms of drug-separated moxibustion and electroacupuncture treating UC.

Acupuncture Points↗

Model of intestinal amebiasis: structural and functional lesions to the rabbit colon mucosa by Entamoeba histolytica lysates.

Although the events occurring during the initial interaction of E. histolytica trophozoites with the mucosa of the large intestine probably determine the invasion by the parasites, an appropriate experimental model does not exist. To develop such a model we used full-thickness rabbit colon preparations (0.28 cm2) mounted in Ussing-type chambers. Untreated preparations had electrophysiological properties (potential difference, short-circuit current and electrical resistance) similar in magnitude and duration to those reported for stripped colonic mucosa. Exposure to E. histolytica trophozoite lysates for up to 80 min produced dose-dependent lesions in the colon, consisting of: (a) increased decay rates for potential difference, short-circuit current and transmural resistance, and (b) mucosal lesions involving vacuolation at the bases and shortening of epithelial cells, loss of intercellular junctions, destruction of microvilli, and necrosis of interglandular epithelial zones. The specificity and speed of the electrophysiologic effects and their correlation with the microscopic lesions suggest that this new model will help to understand the initial pathogenic events of intestinal amebiasis.

Animals↗

Protection against hemorrhagic colitis in an animal model by oral immunization with isogeneic rabbit enteropathogenic Escherichia coli attenuated by truncating intimin.

Strains of Shiga toxin (Stx)-producing Escherichia coli, also called enterohemorrhagic E. coli (EHEC), are important food-borne pathogens for humans. Most EHEC strains intimately adhere to the intestinal mucosa in a characteristic attaching and effacing (A/E) pattern, which is mediated by the bacterial adhesin intimin. Subsequent release of Stx1 and/or Stx2 leads to the frequent development of hemorrhagic colitis and, less commonly, to hemolytic-uremic syndrome. The aim of the present study was to develop an attenuated A/E E. coli strain for use as a vaccine against EHEC infection encoding a truncated intimin lacking adhesive capacity, but which would still express somatic antigens, other products of the locus of enterocyte effacement pathogenicity island, and an immunogenic remnant of the intimin molecule. A single-nucleotide deletion was generated in the eae gene in the prototype rabbit A/E E. coli strain RDEC-1 (O15:H-), which resulted in truncation of intimin by 81 C-terminal residues (860 to 939 amino acids) containing a disulfide loop. Inoculation of rabbits with large doses of the truncated intimin mutant (RDEC-1Deltaeae(860-939)) was well tolerated, as observed by the absence of clinical signs of disease or evidence of intestinal A/E lesions. The efficacy of RDEC-1Deltaeae(860-939) as a vaccine was evaluated by orogastric inoculation of rabbits with RDEC-1Deltaeae(860-939) followed by challenge with the virulent strain RDEC-H19A, an Stx1-producing derivative of wild-type RDEC-1 capable of inducing hemorrhagic colitis in rabbits. Following RDEC-H19A challenge, nonimmunized control rabbits exhibited characteristic weight loss with watery to bloody diarrhea and demonstrated intimate bacterial attachment, effacement of microvilli, submucosal edema, mucosal heterophile infiltrates, and Shiga toxin-induced vascular lesions. In contrast, the RDEC-1Deltaeae(860-939)-immunized rabbits showed no clinical signs of disease, maintained normal weight gain, had reduced fecal shedding of challenge organisms, and showed an absence of gross or microscopic lesions in the intestinal mucosa. Serum antibodies specific to intimin were detected among rabbits immunized with RDEC-1Deltaeae(860-939), indicating that truncation of the intimin functional domain not only attenuated bacterial virulence, but also retained at least some of the immunogenicity of native intimin. Although it is not possible to gauge the exact contribution of residual intimin immunity to protection, this attenuation strategy for A/E E. coli strains shows promise for the development of effective vaccines to prevent EHEC infection in humans and animals.

Adhesins, Bacterial↗

Endoscopic fluorescence detection of dysplasia in patients with Barrett's esophagus, ulcerative colitis, or adenomatous polyps after 5-aminolevulinic acid-induced protoporphyrin IX sensitization.

BACKGROUND: Surveillance of patients with Barrett's esophagus or ulcerative colitis for dysplasia is confined to biopsy specimens taken randomly during endoscopy because dysplasia remains undetectable by visual inspection. We attempted to visualize dysplastic tissue during endoscopy after sensitization with 5-aminolevulinic acid (5-ALA) leading to accumulation and formation of protoporphyrin IX and induction of characteristic red fluorescence of the latter substance using blue light illumination. METHODS: Six patients with histologically proven low- or high-grade dysplasia (Barrett's esophagus 2, ulcerative colitis 1, Billroth-II stomach 1, rectal polyps 2) were treated with oral administration of different concentrations of 5-ALA (10 to 20 mg/kg) or by local instillation of 3 gm 5-ALA in the rectum. Endoscopic fluorescence detection was performed 1 to 6 hours after sensitization using a blue light source and compared with conventional white light endoscopy. Biopsies of fluorescent and nonfluorescent areas were compared with histologic findings. RESULTS: Normal duodenal mucosa and squamous epithelium showed more intense 5-ALA-induced background red fluorescence compared with normal mucosa in the stomach or Barrett's mucosa. Histologically, dysplasia was exclusively found in areas with red fluorescence. False-positive fluorescence was associated with microscopic inflammation of the mucosa or feces in the colon. CONCLUSIONS: 5-ALA-induced protoporphyrin IX fluorescence may be useful in the detection of dysplasia in the gastrointestinal tract by enhancement of endoscopic surveillance of patients at a high risk for dysplasia.

Adenomatous Polyps↗

Escherichia coli O157:H7-induced hemolytic-uremic syndrome: histopathologic changes in the colon over time.

The 1993 E. coli O157:H7 epidemic in the Western United States has provided a unique opportunity to evaluate the histopathologic temporal progression of disease in the colon in children who developed hemolytic uremic syndrome (HUS). In this report we briefly summarize the clinical courses of eight patients and then discuss the colonic pathology observed in specimens obtained at surgery or at the time of autopsy. The patients were divided into two groups: group 1 consisted of six subjects whose colonic samples were obtained during the acute phase of disease, and group 2 consisted of two subjects whose samples were obtained late in their disease. Both the gross and microscopic findings showed that the most severely affected as well as the earliest affected regions of the colon were the left and transverse portions. Only later in the disease progression was there right-sided colon involvement. These findings are in contrast to the distribution described in E. coli O157:H7 hemorrhagic colitis without HUS, thus suggesting a different mechanism of injury.

Biopsy↗

Electron microscopy of the intestine and rectum in acquired immunodeficiency syndrome.

To provide a better understanding of the morphologic changes that take place in the intestine and colon in acquired immunodeficiency syndrome (AIDS), electron microscopy was performed on intestinal or colonic biopsy specimens obtained from 6 patients with AIDS and from 2 patients with AIDS-related lymphadenopathy syndrome. Cryptosporidia were attached to the plasma membrane of epithelial cells in 2 patients and were noninvasive. An invasive protozoan organism identified as Microsporidia was found in 1 patient. Evidence for epithelial cell injury was limited. Unusually prominent secretory granules in colonic epithelial cells (a morphologic counterpart of secretion) was found in 2 patients. Tubuloreticular structures were observed in 7 patients. The structures were found in endothelial cells, lymphocytes, monocytes, intraepithelial lymphocytes, and free in the capillary lumen. Tube- and ring-shaped forms were observed in 2 patients, prominent intraepithelial mast cells in 4 patients, rectal spirochetosis in 1 patient, and pseudomembranous colitis in 1 patient with intestinal and systemic shigellosis. Vesicular rosettes, retroviruses, other viruses, and Mycobacterium avium-intracellulare were not observed. These observations expand our knowledge of morphologic changes in the colonic and intestinal mucosa in patients with AIDS. Tubuloreticular structures are so prominent, in contrast to our previous electron-microscopic observations in other disease and normal states of the intestine and colon, that their finding (though clearly nonspecific) may be a clue to the diagnosis of AIDS in an otherwise equivocal situation.

Acquired Immunodeficiency Syndrome↗

Clinical signs and lesions in gnotobiotic pigs inoculated with Shiga-like toxin I from Escherichia coli.

Gnotobiotic pigs were used as a model to study the contribution of Shiga-like toxin I to natural disease caused by enterohemorrhagic Escherichia coli in calves and human beings. Eleven 2- to 7-day-old gnotobiotic pigs of either sex, obtained by closed hysterotomy, were injected intramuscularly with graded doses of partially purified Shiga-like toxin I derived from a lysogenized Escherichia coli strain. Four other gnotobiotic pigs were injected with a mock toxin preparation obtained from a nonlysogenized culture of the same E. coli strain. All toxin-injected pigs developed diarrhea, and three displayed signs of neurologic disease. Pigs either died or were euthanatized 2 to 4 days post-inoculation. Necrosis of muscle was grossly evident at the site of injection in all toxin-inoculated pigs. Hemorrhage in the lumen of the small and large intestines and blood in the feces were also evident in two toxin-inoculated pigs. Microscopically, severe necrotizing myositis at the injection site, multifocal encephalomalacia, and mucosal infarcts and hemorrhage in the small and large intestines were seen. In small vessels at lesion sites, endothelial cells were frequently swollen or necrotic. Pigs inoculated with mock toxin did not develop diarrhea or exhibit signs of neurologic disease, and the only apparent lesion was mild microscopic myositis at the injection site in 1/4 pigs. The results of this study indicate that Shiga-like toxin I causes vascular damage and ischemic necrosis in the intestines and brains of gnotobiotic pigs. These lesions are similar to those seen in the intestines of calves and human beings with hemorrhagic colitis and in the brains of human beings with thrombotic thrombocytopenic purpura.

Animals↗

Variability in the diagnosis of dysplasia in ulcerative colitis by dynamic telepathology.

Telepathology (TP) is the practice of evaluating pathology cases by the digital transmission of diagnostic slides as either static pictures (static TP) or by a continuous flow of pictures from a robotic microscopy (dynamic TP). The diagnostic efficacy of dynamic TP-based consultation services has not been widely tested. Dysplasia arising in association with chronic ulcerative colitis (CUC) is, at present, the most important marker for an increased risk of malignancy in patients with this disease. However, the diagnosis of dysplasia suffers from a significant degree of intra- and interobserver variability which usually necessitates a second opinion prior to definitive treatment. Thus, it is often necessary to obtain expert consultation of potential dysplasia cases by dedicated gastrointestinal pathologists. The aim of this study was to evaluate the utility and interobserver variability of diagnosing dysplasia in CUC with the use of dynamic TP. Dynamic TP was used to evaluate digitalized images of 38 CUC cases with areas considered negative, indefinite, or positive for dysplasia (low or high grade) independently by seven pathologists. Subsequently, all cases were graded by each of the pathologists by light microscopic examination of the H&E-stained glass slides. The degree of intra- and interobserver variability was determined by Kappa statistics. Overall, there was a poor degree of interobserver agreement (K=0.32) among the seven pathologists after analysis of the cases by dynamic TP. The poorest level of agreement was in the indefinite and low-grade dysplasia categories, whereas the highest level was in the negative and high-grade dysplasia categories. Grouping together several diagnostic categories (for instance: Indefinite and low, or low- and high-grade dysplasia) had no significant effect on the level of agreement. The degree of variability in interpretation of cases by microscopic slide analysis was similar (K=0.35). After reviewing all the cases by microscopic analysis of the glass slides, the diagnosis was changed in 51% of the observations; in the majority of these (61%), the grade of dysplasia was decreased. In summary, the use of dynamic TP for consultation in CUC-associated dysplasia has a poor level of interobserver agreement, but does not differ significantly from that obtained by the evaluation of the cases by microscopic slide analysis. Diagnoses rendered by dynamic TP tend to be of a higher grade compared to that obtained by microscopic slide analysis. Thus, although dynamic TP may be used for the consultation of CUC dysplasia cases, more specific criteria are needed in the general categorization of dysplasia in CUC.

Colitis, Ulcerative↗

Prevention and early diagnosis of cancer in the rectal stump of ulcerative colitis patients after colectomy and topical treatment.

Ulcerative colitis with malignant degeneration and dysplasia can be a precancerous lesion. Therefore, it is necessary to prevent or, at least to diagnose as early as possible any development toward neoplasia in the colon or rectum of the colitis patients. The only reliable guide for a risk of malignant tissue degeneration is dysplasia of the mucosa. A group of 31 patients was studied after total colectomy with ileorectal anastomosis and subsequent topical treatment with enemas containing sulphasalazine and corticosteroids. Two of these patients had mild rectal dysplasia before surgery, seen in a biopsy specimen obtained endoscopically. All the patients were followed for a long time after surgery, with endoscopy and microscopic and ultrastructural observation of rectal biopsy material taken from different sites in the mucosa, both from areas that looked dysplastic by endoscopy and from those that appeared normal. The two patients with presurgical dysplasia, when examined later, one 12 months and one 18 months after surgery, had no rectal dysplasia; the mucosal covering was moderately complete and the anastomosis was functioning. It is considered that to prevent development of cancer in the rectal stump, colectomy should always be followed by regular topical treatment and there should be a check-up at short intervals for early diagnosis of any premalignant areas that might develop. Regression of such lesion was observed to lesser degrees after continuous treatment with the topical medication.

Adolescent↗

Inflammation as a diagnostic keystone and its clinical implications, exemplified by the inflammatory bowel diseases.

Inflammation is a complex process following sublethal injury to tissue and ends with permanent destruction of tissue or with healing. Inflammation has long, long roots in the evolutionary process and as a concept reaches far back in the history of medicine. Inflammation can not be viewed solely in a teleological perspective. Refined by phylogenesis it serves the integrity and survival of groups (species etc.) and not primarily individuals. Inflammation has, in the history of science, been studied on the macroscopic, the microscopic, the dynamic cellular, the immunological, the biochemical/physiological, and the molecular level. Clinicians have for centuries relied on inflammatory signs and symptoms in their diagnostics, even to the extent of being seriously confused, when a subject's inflammatory preparedness is disturbed, as in agranulocytosis, alcoholism, HIV-infection etc. Chronic inflammatory bowel diseases (ulcerative colitis and Crohn's disease) have been studied intensively by inflammologists. The results are partly exchangeable with studies in, for instance, chronic rheumatoid arthritis. They try to answer the over-all question in these diseases: Are we dealing with a normal inflammatory preparedness confronted with a special (unknown) agent, or an abnormal inflammatory preparedness confronted with an ubiquitous agent? The answer will form the basis for the future treatment of these patients, whose diseases remind us of inflammation as man's fellow traveller on "the long phylogenetic march".

Humans↗

Improvement of an experimental colitis in rats by lactic acid bacteria producing superoxide dismutase.

The use of superoxide dismutases (SODs) in inflammatory diseases is hampered by their short circulatory half-life. To determine whether a bacterial supply of SOD into the colon might improve an experimental colitis, the effects of oral treatment with live recombinant lactic acid bacteria producing different amounts of SOD and those of colonic infusion of SOD were compared. Wistar rats were fitted with a catheter in the proximal colon through which TNBS was administered to induce colitis. Animals received a continuous intracolonic infusion of bovine SOD (40 U per rat per day) for 4 days after TNBS or were treated orally with live recombinant Lactococcus lactis or Lactobacillus plantarum strains (10 colony-forming units (CFU)/d), producing or not producing SOD, for 4 days before and after TNBS. SOD activity of bacterial extracts was 0, 26, 74, and 624 units/10 CFU for L. plantarum, L. lactis, L. lactis SOD, and L. plantarum SOD, respectively. Four days after TNBS, macroscopic and microscopic damage, myeloperoxidase (MPO) activity, and nitrotyrosine immunostaining were evaluated. TNBS induced macroscopic and microscopic damages, an increase in MPO activity, and intense immunostaining for nitrotyrosine. Macroscopic damage and MPO activity were reduced by bovine SOD. These parameters and microscopic damages also were reduced by L. lactis, L. lactis SOD, and L. plantarum SOD, but not by L. plantarum. Nitrotyrosine immunostaining was attenuated after treatment with the 4 bacterial strains. Although not all of the anti-inflammatory effects could be attributed directly to SOD, our results suggest that SOD-producing lactic acid bacteria open a novel approach in inflammatory bowel disease treatment.

Administration, Oral↗

A case of toxic megacolon in ulcerative colitis associated with cytomegalovirus infection.

Cytomegalovirus (CMV) infection, which has been shown to complicate the course of ulcerative colitis (UC), has been implicated as a possible etiologic factor in the exacerbation of UC, especially in toxic megacolon. However, CMV infection in patients with UC accompanied by toxic megacolon has rarely been reported. Here we report a case of CMV infection of the colon accompanied by toxic megacolon occurring in UC. A 38-year-old woman had been treated with intravenous hydrocortisone, rectal steroid, and central venous alimentation for 6 weeks under the diagnosis of UC. She was transferred to Akita University Hospital because of increasing bloody diarrhea and abdominal pain. Toxic megacolon was identified by examinations on admission, and she underwent a total colectomy. Examination of the surgical specimen showed severe inflammation of the colon. Microscopically, cytomegalic inclusions were observed in and around the endothelial cells in the inflamed submucosal layer. It can be assumed that CMV infection was a secondary, opportunistic invader superimposed on UC, and that it played an important role in altering the clinical course of the patient.

Adult↗

Experimental ileitis in dogs and colitis in rats with trinitrobenzene sulfonic acid--colonoscopic and histopathologic studies.

Using a novel experimental model of chronic enterocolitis described by Morris et al., we observed sequential changes of mucosal lesions endoscopically and performed histopathological studies. Fisher rats were rectally administered 25 mg of trinitrobenzene sulfonic acid (TNBS) dissolved in 0.5 ml of 50% ethanol (ET). The combination treatment of TNBS and ET produced colitis in rats for over 3 weeks. TNBS itself did not induce any lesions. ET alone induced mucosal lesions, but their severity was much smaller than that induced by TNBS/ET. As an animal model much closer to human inflammatory bowel disease, we have newly developed a canine model of chronic ileitis. Adult mongrel dogs were administered 10 ml of 100% ethanol and 1 g of TNBS dissolved in 10 ml of distilled water (i.e., 100 mg/ml solution) through a 4-lumen double balloon tube which was inserted into the ileum. The TNBS/ET-induced ileitis in dogs persisted for 8 weeks. The mucosal lesions induced by TNBS/ET were characterized as annular or longitudinal ulcers accompanied by extensive lymphocyte infiltration and granulomas, which were similar to macro- and microscopic findings observed in human Crohn's disease. Endoscopic examinations were a valuable tool to obtain sequential information on the development of inflammatory changes in each individual animal. Our canine model would provide various advantages for the study of functional impairment in chronic enterocolitis as well as for the detection of potential therapeutic agents in the human counterpart.

Animals↗