Role of Lymphatic Deficiency in the Pathogenesis and Progression of Inflammatory Bowel Disease to Colorectal Cancer in an Experimental Mouse Model.

BACKGROUND: Inflammatory bowel disease (IBD) is characterized by chronic inflammation, which can progress to colorectal cancer, with duration of disease being the most important risk factor. Although many factors are involved, the pathogenic link between inflammation and cancer and the role played by the lymphatic system have not been fully investigated. This project uses lymphatic-deficient mice (Angiopoietin-2 [Ang2] knockout) to examine the lymphatic system in the progression of IBD to colorectal cancer. METHODS: Angiopoietin-2 wild-type, heterozygote, and knockout mice received a single injection of the procarcinogen azoxymethane and had an IBD-promoting chemical irritant (dextran sodium sulfate) added to their drinking water over a 7-week period. We measured disease activity (weight loss, stool consistency, fecal occult blood) during the study and at sacrifice, collected blood for cytokine/biomarker (Ang2, interleukin [IL] 1-ß, IL-6, tumor necrosis factor α [TNFα], and VEGF-C) enzyme-linked immunosorbent assay analysis, measured colon length, and assessed tumor burden. RESULTS: Ang2 knockout (KO) mice exhibited reduced (55%) survival vs wild-type (100%) and heterozygotes (91%; P < 0.01 and P < 0.0001, respectively). Most (>89%) mice developed tumors, and the incidence of colorectal cancer did not differ among the genotypes (P = 0.32). The tumor area was significantly increased in KO mice (P = 0.004). Of the biomarkers measured in the serum, Ang2 and TNF-α concentrations were significantly different among the genotypes (P = 3.35e-08 and P = 0.003 respectively). Disease activity was significantly increased in KO mice compared with wild-type and heterozygote mice (P = 0.033). CONCLUSIONS: Lymphatic deficiency, defective lymphangiogenesis, and impaired lymphatic-generated inflammation did not protect against clinical IBD or progression to colorectal cancer in this experimental model.

Faculty feedback versus residents' self-assessment of operative performance: Different but complementary.

BACKGROUND: Surgical training requires development of both technical and cognitive skills. The study analyzed feedback by faculty and residents' self-assessments during a laparoscopic training course to identify structure of feedback in this context and compared the focus of trainees to faculty. METHODS: This study collected assessments by surgical residents and faculty during an intensive laparoscopic training course at a single institution. The residents' operative performance was assessed using validated assessment tools including free text feedback. Assessments were completed immediately following procedures. Feedback was analyzed using qualitative method. RESULTS: Eighty (80) residents participated. Three themes were identified: Assessment, instruction and occasion. Faculty provided significantly more feedback than trainees. Moreover, the content of feedback was different. Residents focused on technical performance, while faculty commented on technical and cognitive skills, efficiency and level of independence. Errors were mainly addressed by faculty. CONCLUSION: This study demonstrated differences in cognitive focus of trainees and faculty. Text feedback is informative in understanding perceived challenges. Faculty provided explicit assessment and instruction for improvement. The effectiveness of self-assessment and feedback should be further studied.