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Acidification of rat colon with lactulose. Its effects on the healing of colonic anastomoses.

Preoperative preparation of rats with lactulose, 2.5 ml/kg of a 52.5% w/w solution, for two days resulted in increased bursting pressure and bursting wall tension of low colonic anastomoses three days postoperatively when compared with unprepared controls (85.8, viz, 36.1 mm Hg and 0.55, viz, 0.19 dynes/cm X 10(-5). After seven days, there was no appreciable difference in the rats with colonic acidification and in the controls.

Animals↗

Segmental colonic resection is an appropriate operation for short skip lesions due to Crohn's disease in the colon.

Thirty-six patients have had a segmental colonic resection for Crohn's colitis between 1948 and 1984. There were 2 deaths caused by intraabdominal abscesses present before operation. There were no cases of anastomotic dehiscence in the 29 patients having segmental resection and immediate anastomosis. The reoperation rate at 10 years was 66% (95% confidence interval, 48-84%), the majority of reresections being for recurrent large bowel Crohn's disease. The 10-year reoperation rates were higher than after subtotal colectomy and ileorectal anastomosis (53%; 95% confidence interval, 37-69%) performed in a comparable group of patients with colonic Crohn's disease. The difference did not achieve statistical significance. These findings suggest that when a patient with Crohn's disease has a short segment of diseased large bowel, a segmental resection is feasible and safe.

Adolescent↗

Colonic arteriovenous malformation in a child misinterpreted as an idiopathic colonic varicosis on angiography: remarks on current classification of childhood intestinal vascular malformations.

A case of lower gastrointestinal hemorrhage in a child caused by an arteriovenous malformation (AVM) of the colon is presented. On diagnostic angiography, the lesion was misinterpretated as an idiopathic colonic varicosis because none of the characteristic features of an AVM were present. The role of angiography and shortcomings in nomenclature and classification of intestinal vascular anomalies in childhood are discussed.

Arteriovenous Malformations↗

An immunohistochemical study of colon-ovarian tumor antigen and colon-specific antigen in gynecologic tumors.

The distribution of colon--ovarian tumor antigen (COTA) and colon-specific antigen (CSA) was studied immunohistochemically in gynecologic tumors. The antigens were absent in the serous benign tumors of the ovary and in the normal ovarian tissues, whereas they were detected in some of the mucinous benign tumors. COTA and CSA were present and similarly distributed in most malignant epithelial tumors of the ovary, with their expression increasing with malignancy. Both antigens were almost completely absent in normal glands of the endometrium, but were expressed in many of the endometrial adenocarcinomas. Adenocarcinomas of the cervix were strongly positive for both antigens, and they were also detected in some of the normal cervical glands. However, no relationship was found between the expression of the two antigens and that of argyrophilia, an intestinal metaplasia.

Adenocarcinoma↗

The microbiology of colonization, including techniques for assessing and measuring colonization.

Organisms living on our external and internal body surfaces are the first contact for many potentially pathogenic invaders. Factors that alter this microenvironment include antibiotics, the host immunity, and the various diseases of man and their treatment. Predicting when colonization leads to infection remains an important challenge for every clinician. The maintenance and breakdown of colonization resistance by changes in the native microflora and the body's natural mucosal coating by various extrinsic and intrinsic factors is reviewed in this article. Quantitative culture methods developed to improve the predictive value of a given sampling technique (most notably with bronchoscopy) is presented. Besides improving diagnostic capabilities, quantitative cultures can be used successfully as an epidemiologic tool for some outbreak investigations.

Colony Count, Microbial↗

Inhibition of fungal colonization by Pseudoalteromonas tunicata provides a competitive advantage during surface colonization.

The marine epiphytic bacterium Pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. In this study, we test the hypothesis that the ability to inhibit fungi provides P. tunicata with an advantage during colonization of a surface. Studies on a transposon-generated antifungal-deficient mutant of P. tunicata, FM3, indicated that a long-chain fatty acid-coenzyme A ligase is involved in the production of a broad-range antifungal compound by P. tunicata. Flow cell experiments demonstrated that production of an antifungal compound provided P. tunicata with a competitive advantage against a marine yeast isolate during surface colonization. This compound enabled P. tunicata to disrupt an already established fungal biofilm by decreasing the number of yeast cells attached to the surface by 66% +/- 9%. For in vivo experiments, the wild-type and FM3 strains of P. tunicata were used to inoculate the surface of the green alga Ulva australis. Double-gradient denaturing gradient gel electrophoresis analysis revealed that after 48 h, the wild-type P. tunicata had outcompeted the surface-associated fungal community, whereas the antifungal-deficient mutant had no effect on the fungal community. Our data suggest that P. tunicata is an effective competitor against fungal surface communities in the marine environment.

Antifungal Agents↗

Colonization and disinfection of biofilms hosting coliform-colonized carbon fines.

The documented release of carbon fines from granular activated carbon filters is a concern for drinking water utilities, since these particles may carry coliform and even pathogenic bacteria through the disinfection barrier. Such a breakthrough could have an impact on distribution system biofilms. Using total cell counts, specific monoclonal antibody staining, and computerized image analysis, we monitored the colonization of introduced Klebsiella pneumoniae associated with carbon fines in mixed-population biofilms. The particles transported the coliforms to the biofilms and allowed successful colonization. Chlorine (0.5 mg/liter) was then applied as a disinfectant. Most K. pneumoniae along with the carbon fines left the biofilm under these conditions. The impact of chlorine was greater on the coliform bacteria and carbon fines than on the general fixed bacterial population. However, 10% of the introduced coliforms and 20% of the fines remained in the biofilm. The possibility that this represents a mechanism for bacteria of public health concern to be involved in regrowth events is discussed.

Journal Article↗

Ecology of Candida albicans gut colonization: inhibition of Candida adhesion, colonization, and dissemination from the gastrointestinal tract by bacterial antagonism.

Antibiotic-treated and untreated Syrian hamsters were inoculated intragastrically with Candida albicans to determine whether C. albicans could opportunistically colonize the gastrointestinal tract and disseminate to visceral organs. Antibiotic treatment decreased the total population levels of the indigenous bacterial flora and predisposed hamsters to gastrointestinal overgrowth and subsequent systemic dissemination by C. albicans in 86% of the animals. Both control hamsters not given antibiotics and antibiotic-treated animals reconventionalized with an indigenous microflora showed significantly lower gut populations of C. albicans, and C. albicans organisms were cultured from the visceral organs of 0 and 10% of the animals, respectively. Conversely, non-antibiotic-treated hamsters inoculated repeatedly with C. albicans had high numbers of C. albicans in the gut, and viable C. albicans was recovered from the visceral organs of 53% of the animals. Examination of the mucosal surfaces from test and control animals indicated further that animals which contained a complex indigenous microflora had significantly lower numbers of C. albicans associated with their gut walls than did antibiotic-treated animals. The ability of C. albicans to associate with intestinal mucosal surfaces also was tested by an in vitro adhesion assay. The results indicate that the indigenous microflora reduced the mucosal association of C. albicans by forming a dense layer of bacteria in the mucus gel, out-competing yeast cells for adhesion sites, and producing inhibitor substances (possibly volatile fatty acids, secondary bile acids, or both) that reduced C. albicans adhesion. It is suggested, therefore, that the indigenous intestinal microflora suppresses C. albicans colonization and dissemination from the gut by inhibiting Candida-mucosal association and reducing C. albicans population levels in the gut.

Adhesiveness↗

Genetic relationship of putative colonization factor O166 to colonization factor antigen I and coli surface antigen 4 of enterotoxigenic Escherichia coli.

Plasmid DNA from two strains of enterotoxigenic Escherichia coli harboring genes encoding coli surface antigen 4 (CS4) and from seven Indian enterotoxigenic E. coli isolates cross-hybridized at low stringency but not at high stringency with two polynucleotide probes derived from the colonization factor antigen I (CFA/I) operon. Low-stringency Southern blot hybridization of PstI-digested plasmid DNA from the seven Indian isolates yielded characteristic restriction fragment patterns, distinct from those of CS4- and CFA/I-associated plasmid DNA. Two of the Indian strains were transformed with a recombinant plasmid harboring the cfaD gene, which encodes a positive regulator of CFA/I and CS4 genes. The cfaD transformants produced large amounts of putative colonization factor O166 (PCFO166) irrespective of whether the nutrient agar contained bile salts, a growth factor otherwise required for adequate PCFO166 expression. A considerable interstrain variation in the level of PCFO166 production could be explained by differences in the proportion of bacteria that were fimbriated, as visualized by electron microscopy. The N-terminal amino acid sequence of PCFO166 fimbrial protein showed a high degree of homology with the corresponding sequences of CFA/I and CS4.

Amino Acid Sequence↗

Use of nonradioactive DNA hybridization for identification of enterotoxigenic Escherichia coli harboring genes for colonization factor antigen I, coli surface antigen 4, or putative colonization factor O166.

We developed an accurate nonradioactive colony hybridization assay (NCHA) using a digoxigenin-labeled polynucleotide probe and an antidigoxigenin alkaline phosphatase conjugate for the identification of enterotoxigenic Escherichia coli (ETEC) harboring genes for colonization factor antigen I (CFA/I), coli surface antigen 4 (CS4), or putative colonization factor O166 (PCFO166). In this 2-day assay, visual registration of color intensity could be used to distinguish between CFA/I-positive strains and strains with the genetic potential to express CS4 or PCFO166. A rapid NCHA was developed by which the results could be read visually 7 h and 45 min after inoculation of the bacteria. In the rapid NCHA, densitometry verified the visual discrimination between four groups of E. coli; ETEC with the CFA/I gene, ETEC with the CS4 gene, ETEC with the PCFO166 gene, and E. coli strains that lack such genes. As a confirmatory test, plasmids from ETEC with the CFA/I, CS4, or PCFO166 gene were differentiated by their characteristic restriction fragment patterns in nonradioactive Southern blot hybridization.

Antigens, Bacterial↗

T cell receptor-zeta and granzyme B expression in mononuclear cell infiltrates in normal colon mucosa and colon carcinoma.

BACKGROUND: Whereas the presence of a lymphoid infiltrate has been associated with a favourable prognosis in colorectal carcinoma, the proliferative and cytotoxic responses of freshly isolated tumour infiltrating lymphocytes are frequently impaired. In mice, tumour induced immune suppression has been associated with a decreased expression of the zeta-chain of the T cell receptor (TCR)-CD3 complex, and loss of mRNA for granzyme B. AIM: To compare the expression of TCR-zeta and granzyme B in lymphocytes infiltrating normal colonic mucosa and Duke's A and D colorectal carcinomas. SPECIMENS: Paraffin wax embedded normal (n = 10) and malignant colonic mucosa (seven Dukes's A, nine Dukes's D). METHOD: Immunohistochemistry. RESULTS: The numbers of TCR-zeta + lymphocytes decreased from normal mucosa to Dukes's D carcinomas. In contrast, granzyme B+ lymphocytes were more frequent in Dukes's A carcinomas than in normal mucosa, but disappeared from advanced stage tumours. Granzyme B expressing cells were mainly CD3- (natural killer/lymphokine activated killer cells) in normal mucosa, but CD3+ in tumours, indicating the presence of activated cytotoxic T lymphocytes. In vitro culture of tumour infiltrating lymphocytes rapidly restored the expression of both molecules. CONCLUSION: The frequency of TCR-zeta + and granzyme B+ lymphocytes is decreased in advanced stage colorectal carcinomas. The restoration of expression during in vitro stimulation suggests the presence of tumour derived suppressive factors in situ.

CD3 Complex↗

Colonization of the small intestine of weaned pigs by enterotoxigenic Escherichia coli that lack known colonization factors.

Intestinal colonization of 3-week-old weaned pigs by enterotoxigenic Escherichia coli (ETEC) strains that were originally isolated from weaned pigs with fatal diarrhea and that lacked K88, K99, F41, and 987P adhesins (4P- ETEC) was studied by histologic, immunofluorescent, and electron microscopic techniques. In the first experiment, 16 principal pigs were inoculated orogastrically with ETEC strain 2134 (serogroup O157: H19) or 2171 (serogroup 0141:H4), and eight control pigs were not inoculated. In the second experiment, 24 principals were inoculated with ETEC strain 2134, and 12 controls were inoculated with a nonenterotoxigenic strain of E. coli. Principal and control pigs were necropsied at intervals from 24 to 72 hours after inoculation of principals to provide the tissues used for this report. Results from the two experiments and with both ETEC strains were similar and therefore were combined. Adhesion by 4P- ETEC was demonstrated in ileum but not in cecum or colon in 22/40 principal pigs sampled at 24 to 72 hours after orogastric inoculation. Adherent bacteria were most apparent on the intestinal villi covering Peyer's patches. Only occasional adherent bacteria were detected in ileal sections from a few (4/20) of the control pigs. Adherence by 4P- ETEC was characterized by "patches" of bacteria closely associated with the lateral surfaces and less frequently with the tips and the bases of intact villi. In most cases, the adherent bacteria were separated from epithelial cell microvilli and other bacterial cells by a 50-400-nm space. Filamentous bacterial appendages bridged this space and formed a network among adjacent bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Abnormal colonization of neonates in an ICU: conversion to normal colonization by pharyngeal implantation of alpha hemolytic streptococcus strain 215.

Normal bacterial flora provide a natural defense mechanism against infection. Our experience indicates that "normal" flora for the ICU neonate contains alpha hemolytic (alpha-) streptococci as the predominant organism. The purpose of the current investigation is to study the feasibility of implanting a carefully selected, naturally occurring strain of alpha-streptococcus in the nasopharynx of neonates considered to be at high risk of infection because of the abnormal colonization of their pharynx with potential pathogens. Twenty-two infants in the neonatal intensive care unit have received nasopharyngeal implantation with strain 215 alpha-streptococcus. In 16 infants, alpha-streptococci, including the implant strain in pure or mixed alpha-streptococcal populations, constituted the predominant pharyngeal flora within 48 to 72 hr of implantation. The implant strain was not recovered from the remaining six infants. The procedure was apparently innocuous in this small number of patients. We conclude that implantation of a streptococcus can be established in the pharynx of infants abnormally colonized with pathogenic organisms in high titer and that successful implantation of strain 215 can result in prompt development of normal pharyngeal flora, with alpha-streptococci predominant, within 48 hr. There has been no evidence of infection or other adverse reaction caused by the implant strain.

Bacterial Infections↗

Trypanosoma cruzi infection and/or administration of the nonsteroidal anti-inflammatory nimesulide increase the number of colonic crypts overexpressing metallothioneins in rat colon carcinogenesis.

Trypanosoma cruzi infection and nonsteroidal anti-inflammatory drugs inhibit colorectal carcinogenesis by mechanisms not completely known and metallothionein proteins (MTs) may be involved in this process. Sixty-six male Wistar rats weighing 90 to 120 g were randomly divided into seven groups (GI to GVII). GI, GII and GIII animals were subcutaneously infected with 200,000 trypomastigote forms of the Y strain of T. cruzi. After 8 weeks, GI, GII, GIV, and GVI were injected with one weekly subcutaneous dose of 12 mg/kg dimethylhydrazine for 4 weeks. In sequence, GI, GIV and GV were treated with nimesulide (10 mg/kg per dose, five times per week for 8 weeks). Groups I, III, IV, and VI had 12 animals, and each of the other groups had 6 animals. All the animals were euthanized 8 weeks after the last dimethylhydrazine injection. The colons were fixed and processed for MT immunohistochemistry. The index of MT-overexpressing colonic crypts (MTEC) was estimated as the percentage of MT-stained crypts in relation to the total number of crypts scored. Five hundred crypts per animal were scored. Data were analyzed by the Kruskal-Wallis test followed by the Dunn test. There was an increase in MTEC index in the groups either infected with T. cruzi or treated with nimesulide or both infected and treated when compared to control (401, 809, and 1011%, respectively). We suggest that the increased formation of MTEC may be related to the protection against carcinogenesis provided both by T. cruzi infection and nimesulide.

Animals↗

Immunohistochemical detection of the hMLH1 and hMSH2 proteins in hereditary non-polyposis colon cancer and sporadic colon cancer.

Defects in DNA mismatch repair system are involved in carcinogenesis of sporadic and inherited human cancers. We assessed the feasibility of using immunohistochemistry to detect tumors with DNA mismatch repair deficiency. We analyzed 81 samples (74 colon cancers (CC), 1 colon dysplasia and 6 extracolonic cancers) for hMLH1 and hMSH2 protein expression, microsatellite instability (MSI) and/or mutational analysis. A meta-analysis of the published data on immunohistochemistry of hMLH1/hMSH2 proteins was performed. Sensitivity and specificity of the method was calculated. Twenty four of 29 tumors from hMLH1/hMSH2 mutation carriers and 10 of 13 sporadic high frequency MSI tumors lost one of the proteins. None of the 42 tumors with stable microsatellites or low frequency MSI lost the proteins. Based on literature review of 49 publications on colorectal cancer, hMLH1 immunohistochemistry was able to detect 136 of 154 tumors from hMLH1 germline mutation carriers (the sensitivity of 88.3% [95%CI, 85.8-90.8%]), hMSH2 immunohistochemistry detected 99 of 109 tumors from hMSH2 mutation carriers (the sensitivity of 90.8% [95%CI, 88.5-93.1%]), and hMLH1/hMSH2 immunohistochemistry identified 1262 of 1382 tumors with high-frequency microsatellite instability not correlated with mutational analysis (the sensitivity of 91.3% [95%CI, 90.4-92.2%]). The specificity of the method was 99.4% (95%CI, 99.2-99.6%). In conclusion, immunohistochemistry of hMLH1 and hMSH2 proteins is a useful method to predict the presence of mismatch repair deficiency, although its sensitivity is lower than that of MSI analysis.

Adaptor Proteins, Signal Transducing↗

Crohn's disease of the colon. III. Toxic dilatation of the colon in Crohn's colitis.

In a group of 160 patients with Crohn's disease involving the colon, there were seven patients with toxic dilatation, four with granulomatous colitis and three with ileocolitis, all successfully treated without mortality. This complications is more common than previously recognized in Crohn's colitis. In Crohn's disease, toxic dilatation is less likely to proceed to perforation of the bowel, because of the nature of the pathology and is more likely to respond to conservative measures: intubation, with decompression, corticotropin, steroids and high-dose antibiotic administration. Although patients do recover from this life-threatening complication with conservative management, the majority of patients, if not all, will ultimately come to surgical excision of the colon. If surgery is mandatory, it should be carried out early, rather than late, in the patient who is failing to respond to medical therapy, certainly before the development of perforation, massive hemorrhage, or gram negative sepsis with shock. The surgical therapy will depend upon the state of the bowel at laparotomy. Thus, an intact bowel in a young patient, would favor subtotal colectomy or proctocolectomy; a sealed perforation, a diverting ileostomy with skin level colostomy decompression as suggested by Turnbull and a free perforation, the minimum adequate procedure which will tide the patient over the early postoperative period. Diverting ileostomy alone has been effective in two of our patients but should be avoided in ulcerative colitis. The critically ill patient with the ominous finding of "disintegrating colitis" and multiple leaks, will require nothing less than total radical excision of the diseased bowel in the hope of immediate salvage.

Adrenocorticotropic Hormone↗

Molecular biology of colon polyps and colon cancer.

From a histologic and endoscopic standpoint, colon and rectal cancer (CRC) begins as a small neoplastic polyp which progressively enlarges and transforms through a dysplasia stage into invasive cancer. Recently, molecular abnormalities underlying the adenomacarcinoma progression have been defined. The adenomatous polyposis coli (APC) gene and mismatch repair genes are found to be dysfunctional early in the neoplastic process; either as inherited or somatic mutations. Subsequently, polyps progress to cancer along one of two paths depending on which gene is abnormal. When the APC gene is the initial mutation tumor development follows the "loss of heterozygocity" (LOH) pathway. If mismatch repair genes are altered, the "replication error" (RER) pathway is followed. Somatic mutations of the K-ras oncogene and the MCC, DCC, and p53 tumor suppressor genes accumulate in the LOH pathway and mark the progression through polyp stages. Microsatellite instability is a characteristic of the RER pathway but the precise genes involved in this pathway currently are not known. Defining these pathways has led to a new classification scheme for CRC with resultant changes in our clinical approach to screening, surveillance, and treatment.

Adenomatous Polyposis Coli↗