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Background: The validity of current animal colon cancer models is questionable. This study was performed to evaluate whether colonoscopic injection of a murine colon cancer cell line into the cecal wall of immunocompetent rats leads to a solid tumor. Methods: A bolus of bowel prep was given to BD-IX rats. Anesthesia was injected intraperitoneally. Video fiberscope allowed for irrigation and suction. Failure was inability to reach/inject cecum. Procedure was performed by four surgeons; 100 μl of colon tumor cell suspension (DHD/K12TRb; 10 million cells in 0.1 ml) was injected into cecal wall with 23-gauge needle placed on 3 mm wire resulting in a blister. Rats were allowed to recover. Solid tumor growth was measured at scheduled necropsy at 4 weeks. Sample size (107 rats: type I error 0.05; power 80%) was based on a pilot study. Data were presented as median (range). Results: A total of 107 male BD-IX retired breeders weighing 356 g (range 256-432 g) underwent colonoscopy with submucosal injection of cecal wall. A single solid cecal cancer was identified in 98 (91.5%) rats at scheduled necropsy. Histology confirmed adenocarcinoma with tumor size of 4 mm (range 2.6-8.4 mm). Peritoneal carcinomatosis was found in ten (9.3%) rats. Distant metastases were found in three (2.8%) rats. Complications occurred in four (3.8%) rats: two aspirations and two colon perforations. Conclusions: A solid cecal tumor without carcinomatosis or metastasis has been developed by colonoscopic injection of a rat colon cancer cell line in 79% of immunocompetent rats. [ABSTRACT FROM AUTHOR]

PURPOSE: Acute diverticulitis is a disease with a wide clinical spectrum, ranging from a phlegmon (stage Ia), to localized abscesses (stages Ib and II), to free perforation with purulent (stage III) or feculent peritonitis (stage IV). While there is little debate about the best treatment for mild episodes and/or very severe episodes, uncertainty persists about the optimal management for intermediate stages (Ib and II). The aim of our study was therefore to define the role of computed tomography (CT) and to analyze its impact on the management of acute diverticulitis.METHODS: We retrospectively analyzed 511 patients (296 males, 215 females) admitted for acute diverticulitis between January 1994 and December 2003. Excluded were patients with stoma reversal only,“diverticulitis” mimicked by cancer, or significantly deficient patient records. Patients were analyzed either as a whole or subgrouped according to age (<40 yr,>40 yr). A modified Hinchey classification was used to stage the severity of acute diverticulitis.RESULTS: In 99 patients (19.4%), an abscess was found (74 pericolic, 25 pelvic, median diameter: 4.0 cm). CT-guided drainage was performed in 16 patients, one failure requiring a two-stage operation. Whereas conservative treatment failed in 6.8% in patients without abscess or perforation, 22.2% of patients with an abscess required an urgent resection (68.2%, one-stage, 31.8%, two-stage). Recurrence rates were 13% for mild cases, as compared to 41.2% in patients with a pelvic abscess (stage II) treated conservatively with/without CT-guided drainage. Of all surgical cases, resection/primary anastomosis was achieved in 73.6% with perioperative mortality of 1.1% and leak rate was 2.1%.CONCLUSIONS: CT evidence of a diverticular abscess has a prognostic impact as it correlates with a high risk of failure from nonoperative management regardless of the patient's age. After treatment of diverticulitis with CT evidence of an abscess, physicians should strongly consider elective surgery in order to prevent recurrent diverticulitis.(Am J Gastroenterol 2005;100:1-8) [ABSTRACT FROM AUTHOR]