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Colonic Adenomas (colonic + adenoma)
Selected AbstractsDIAGNOSIS OF COLONIC ADENOMAS BY NEW AUTOFLUORESCENCE IMAGING SYSTEM: A PILOT STUDYDIGESTIVE ENDOSCOPY, Issue 2007Noriya Uedo Detection and removal of adenoma by colonoscopy is an important means of preventing cancer. Autofluorescence endoscopy can visualize flat or isochromatic tumor that was not detectable by white light endoscopy by the difference in tissue fluorescence properties. Recently, a new autofluorescence imaging system (AFI, Olympus Medical Systems) using a combination of autofluorescence and reflection imaging has been developed. The purpose of the present paper was to investigate its feasibility in detection of colonic adenoma in a clinical setting. A total of 64 patients were randomly assigned to AFI or white light groups, and the distal sigmoid colon and the rectum was observed under autofluorescence or white light followed by the other mode of observation by a different endoscopist. The diagnostic ability of each method for detection of neoplasms was compared in relation to the histology as a reference standard. Sensitivity and specificity of AFI for detection of neoplastic polyps was 84% and 60%, respectively, and were similar to those of white light colonoscopy: 90% and 64%. Conventional colonoscopy overlooked more flat lesions including one adenocarcinoma. AFI has the potential to detect more flat lesions but efficacy was unable to be demonstrated in the restricted population. Further investigations are needed to determine optimum usage. [source] Reversal of expression of 15-lipoxygenase-1 to cyclooxygenase-2 is associated with development of colonic cancerHISTOPATHOLOGY, Issue 4 2007M Yuri Aims:, Two different pathways of linoleic acid (LA) metabolism have opposite effects on the development of colonic cancer: a protumoral prostaglandin cascade metabolized by cyclooxygenase (COX)-2, and an antitumoral peroxisome proliferator-activated receptor (PPAR)-, ligands metabolized by 15-lipooxygenase (LOX)-1. The aim was to examine the switching of the two LA metabolic pathways in colonic adenomas and carcinomas. Materials and methods:, The expression of 15LOX-1 mRNA and COX-2 protein was examined in 54 adenomas, 21 pTis carcinoma-in-adenoma lesions and 36 pT3/p Stage II carcinomas of the colon by in-situ hybridization and immunohistochemistry, respectively. Results:, 15LOX-1 expression was found in 89% (48 of 54) of adenomas, 43% (nine of 21) of adenomas and 10% (two of 21) of carcinomas in carcinoma-in-adenoma lesions, but not in pT3 carcinomas (P < 0.0001). In contrast, COX-2 production was found in 11% (six of 54) of adenomas, 52% (11 of 21) of adenomas and 71% (15 of 21) of carcinomas in carcinoma-in-adenoma lesions, and 92% (33 of 36) of pT3 carcinomas (P < 0.0001). Concurrence of 15LOX-1 down-regulation and COX-2 up-regulation was found in 6% (three of 54) of adenomas, 33% (seven of 21) of adenomas and 71% (15 of 21) of carcinomas in carcinoma-in-adenoma lesions, and 92% (33 of 36) of pT3 carcinomas (P < 0.0001). Conclusions:, These results suggest that switching of LA metabolism by reversal of the expression of 15LOX-1 and COX-2 is associated with acquisition of malignant potential in colonic neoplasia. [source] Flat adenoma in colon: Two decades of debateJOURNAL OF DIGESTIVE DISEASES, Issue 4 2010Patrick CP LAU The existence of flat adenomas in the colon is well recognized. Whether they represent a distinct disease with a pathogenetic pathway different from that of the classical adenoma-carcinoma sequence in colorectal tumorigenesis and have higher malignant potential remains a matter of debate. To review the epidemiology, clinical features, detection and management of flat and depressed (non-polypoid) colonic neoplasm, we performed a thorough literature review on studies focusing on the prevalence, histological features, genetics, detection and treatment of flat and depressed (non-polypoid) colonic neoplasm. A high percentage of severe dysplasia in flat colonic adenomas has not been consistently demonstrated. Their malignant potential appears to be size-dependent. Flat adenomas are found to have a lower incidence of major genetic abnormalities involved in the classical adenoma-carcinoma sequence and that has raised suspicions that they may have a different pathogenesis. The depressed type of colorectal carcinoma is uncommon but shows more aggressive behavior. More advanced colonoscopic techniques, such as chromoendoscopy, may enhance the detection of small and inconspicuous colonic neoplastic lesions that lack a protruding configuration. It is essential for endoscopists to appreciate the existence and clinical significance of flat and depressed colonic lesions as an important variant of colonic neoplasms so that the goal of reducing colorectal carcinoma incidence by polypectomy can be better achieved. [source] Flat colonic adenomas in Malaysia: Fact or fancy?JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2003SHANMUGARAJAH RAJENDRA Abstract Background: Some two-thirds of colorectal carcinomas arise from adenomatous polyps, and as such, screening by colonoscopy and polyp removal should significantly reduce colorectal cancer. This has not been the case, as evidenced by recent studies, which revealed that endoscopy failed to prevent up to 50% of all subsequent carcinomas. Flat or depressed adenomas, frequently reported from Japan but rarely elsewhere, might explain the ,missed carcinomas.' Detection of flat adenomas has not been previously reported from Malaysia. Methods: In the present prospective study, 426 consecutive patients underwent colonoscopic examination between March 1997 and January 2000, for a variety of bowel symptoms. The examinations were performed by an experienced endoscopist using a standard colonoscope and methylene blue dye spraying technique. Macroscopically, flat adenomas were defined using the criteria proposed by Sawada. Results: Twenty-nine adenomas were identified in 12 patients, of which 15 were polypoid and 14 were flat, with no depressed lesions. Eight polypoidal lesions and all the flat adenomas contained mild or moderate areas of epithelial dysplasia. Seven severely dysplastic polyps were identified. One Duke's A polypoidal cancer and two advanced carcinomas were also found. All the severely dysplastic lesions and Duke's A carcinomas were found in polyps greater than 10 mm in mean size. The flat adenomas were all less than 5 mm in size. Conclusions: A significant proportion of colonic adenomas in Malaysian patients appear as small flat lesions, which could easily be missed during endoscopy. Increased recognition and treatment of flat adenomas among colonoscopists is warranted. [source] Review article: bifidobacteria as probiotic agents , physiological effects and clinical benefitsALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2005C. PICARD Summary Bifidobacteria, naturally present in the dominant colonic microbiota, represent up to 25% of the cultivable faecal bacteria in adults and 80% in infants. As probiotic agents, bifidobacteria have been studied for their efficacy in the prevention and treatment of a broad spectrum of animal and/or human gastrointestinal disorders, such as colonic transit disorders, intestinal infections, and colonic adenomas and cancer. The aim of this review is to focus on the gastrointestinal effects of bifidobacteria as probiotic agents in animal models and man. The traditional use of bifidobacteria in fermented dairy products and the GRAS (,Generally Recognised As Safe') status of certain strains attest to their safety. Some strains, especially Bifidobacterium animalis strain DN-173 010 which has long been used in fermented dairy products, show high gastrointestinal survival capacity and exhibit probiotic properties in the colon. Bifidobacteria are able to prevent or alleviate infectious diarrhoea through their effects on the immune system and resistance to colonization by pathogens. There is some experimental evidence that certain bifidobacteria may actually protect the host from carcinogenic activity of intestinal flora. Bifidobacteria may exert protective intestinal actions through various mechanisms, and represent promising advances in the fields of prophylaxis and therapy. [source] Overexpression of serine,threonine receptor kinase-associated protein in colorectal cancersPATHOLOGY INTERNATIONAL, Issue 4 2007Chang Jae Kim Transforming growth factor-, (TGF-,) regulates many cellular processes, including cellular proliferation and differentiation. Disruption of the TGF-, signaling pathway can lead to cancer. Serine,threonine receptor kinase-associated protein (STRAP), an inhibitor of TGF-, signaling, is an important regulator of cell proliferation. Here, in order to investigate the roles of STRAP in colorectal carcinogenesis, the expression of the STRAP protein was investigated in 59 colonic adenomas and 123 colorectal cancers by immunohistochemistry. Upregulation of STRAP protein was observed in 30 (50.8%) of 59 adenomas and 87 (70.7%) of 123 cancers, respectively. Statistically, overexpression of STRAP protein was not associated with clinicopathological parameters and 5 year survival (P > 0.05). Interestingly, significant association was observed between STRAP and Ki-67 positivity (P < 0.05), suggesting that STRAP contributes to an increased proliferate potential of tumor cells. These results indicate that upregulation of STRAP might play a role in tumor development as an early event for colorectal cancers. 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