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BackgroundDoublecortin and calcium/calmodulin-dependent protein kinase-like-1 (DCAMKL1) is a candidate marker for progenitor cells in the gastrointestinal mucosa. Lineage cells in the gastric mucosa are derived from progenitor cells, but this process can be altered after injury. Therefore, we explored DCAMKL1 expression under pathological conditions.MethodsAn immunohistochemical analysis was performed in rat stomach with acute superficial injury, chronic ulcer, intestinal metaplasia and dysplasia.ResultsDCAMKL1 was exclusively expressed in immature quiescent cells in the isthmus of normal fundic glands, where putative progenitor cells are thought to reside. DCAMKL1-positive cells and proliferating cells shed into the lumen after superficial injury and re-appeared during the regenerative process, mainly in the superficial mucosa. In the marginal mucosa around the active ulcer, parietal and chief cells diminished, foveolar hyperplasia was evident, and trefoil factor family 2 (TFF2)/spasmolytic polypeptide-expressing metaplasia (SPEM) emerged at the gland base. DCAMKL1 cells re-emerged in the deep mucosa juxtaposed with SPEM and proliferating cells. In the healing ulcer, the TFF2 cell population expanded and seemed to redifferentiate to chief cells, while proliferating cells and DCAMKL1 cells appeared above and below the TFF2 cells to promote healing. SPEM appeared and PCNA cells increased in the intestinalized mucosa, and DCAMKL1 was expressed in the proximity of the PCNA cells in the deep mucosa. DCAMKL1, PCNA and TFF2 were expressed in different dysplastic cells lining dilated glands near SPEM.ConclusionThe ultrastructural appearance of DCAMKL1-positive cells and the expression patterns of DCAMKL1 in normal and pathological states indicate that the cells belong to a progenitor cell population. DCAMKL1 expression is closely associated with TFF2/SPEM cells after injury. DCAMKL1 cells repopulate close to proliferating, hyperplastic, metaplastic and dysplastic cells, and the progenitor zone shifts according to the pathological circumstances.

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Background/Aims: Although colonic diverticular bleeding (CDB) often ceases spontaneously, re-bleeding occurs in about 30%. Bleeding diverticulum can be treated directly by endoscopic hemostasis; however, it is difficult to perform colonoscopy in all cases with limited medical resource and certain risks. The aim of this study was to clarify who should undergo colonoscopy as well as appropriate methods of initial management in CDB patients. Methods: A total of 285 patients who were diagnosed as CDB and underwent colonoscopy from March 2004 to October 2015 were retrospectively analyzed. First, the association between re-bleeding and various factors including patients’ background and initial management were analyzed. Second, the examination conditions that influenced bleeding point identification were analyzed. Results: Of 285 patients, 187 were men and 98 were women. Median age was 75 years, and the median observation period was 17.5 months. Re-bleeding was observed in 79 patients (28%). A history of CDB (OR 2.1, p = 0.0090) and chronic kidney disease (CKD; OR 2.3, p = 0.035) were risk factors, and bleeding point identification (OR 0.20, p = 0.0037) was a preventive factor for re-bleeding. Bleeding point identification significantly reduced approximately 80% of re-bleeding. Furthermore, extravasation on CT (OR 3.7, p = 0.031) and urgent colonoscopy (OR 5.3, p < 0.001) were predictors for identification of bleeding point. Compared to bleeding point identification of 11% in all patients who underwent colonoscopy, identification rate in those who had extravasation on CT and underwent urgent colonoscopy was as high as 70%. Conclusions: Contrast-enhanced CT upon arrival is suggested, and patients with extravasation on CT would be good candidates for urgent colonoscopy, as well as patients who have a history of CDB and CKD.