Background and Aim: Underwater endoscopic mucosal resection (UEMR) is effective for superficial non-ampullary duodenal epithelial neoplasms (SNADEN). However, the incidence of residual lesion after UEMR, especially for large lesions (≥20 mm), and their prognosis remain unclear. We aimed to assess the incidence of residual lesions and further outcomes after UEMR for SNADEN. Methods:We carried out a retrospective study at a tertiary cancer institute. Candidates for the study were systematically retrieved from an endoscopic and pathological database from Results: A total of 162 SNADEN resected with UEMR were analyzed. Median (range) procedure time was 5 (1-70) min. En bloc resection rates for large lesions (≥20 mm) and small lesions (<20 mm) were 14% and 79%, respectively. Intraprocedural bleeding occurred in one (0.6%) case, but no intraprocedural perforation occurred during the study. Delayed bleeding occurred in two (1.2%) cases and delayed perforation occurred in one (0.6%) case. A total of 157 (97%) lesions were followed up by at least one endoscopic examination. Of these lesions, residual lesions were recognized in seven cases (5%). Additional UEMR was carried out in five lesions and underwater cold snare polypectomy in one lesion. One lesion was observed without additional treatment. After salvage intervention, no cases experienced further residual lesions. Conclusion:Although UEMR for SNADEN can be relevant when other efficacious procedures are unavailable, careful follow up for residual lesions is required especially after piecemeal resection for large lesions.

Background and Aim The true incidence of incomplete muscularis mucosa resection with cold snare polypectomy (CSP) is unknown. We examined the incidence of incomplete muscularis mucosa resection both with and without cold snare defect protrusion (CSDP). Methods We prospectively enrolled patients undergoing polypectomy for 4 to 9mm nonpedunculated polyps. We evaluated the presence of CSDP immediately following CSP and biopsied the CSDP or the center of the mucosal defect without CSDP. The presence of the muscularis mucosa and any residual polyp in the biopsies was evaluated histologically. The primary outcome was the incidence of incomplete mucosal layer resection defined as the presence of muscularis mucosa or residual polyp in the biopsies. Results From August 2017 to October 2018, 188 patients were screened, and 357 polyps were included. CSDP was detected in 122/355 (34%) evaluated mucosal defects. Excluding five lesions requiring hemostasis immediately following CSP, 352 mucosal defects were biopsied. After excluding 102 biopsies containing normal mucosa, we evaluated 250 biopsies. The overall incidence of incomplete mucosal layer resection was 63% (159/250), 76% (68/90) with CSDP and 57% (91/159) without CSDP (P < 0.01). Both univariate and multivariate analyses showed that size (≥ 6 mm), resection time (≥ 5 s), and serrated lesions were risk factors for CSDP. Conclusions Cold snare defect protrusion (CSDP), which was present with 36%, was a good indicator for incomplete mucosal layer resection. Even in nonCSDP polypectomies, 57% of the mucosal layer was not removed completely. Thus, CSP should be used for intra‐epithelial lesions only, and careful pretreatment evaluation is recommended.

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Oxytocin is a central neuromodulator required for facilitating mate preferences for familiar individuals in a monogamous rodent (prairie vole), irrespective of sex. While the role of oxytocin in mate choice is only understood in a few monogamous species, its function in nonmonogamous species, comprising the vast majority of vertebrate species, remains unclear. To address this issue, we evaluated the involvement of an oxytocin homolog (isotocin, referred herein as oxt) in mate choice in medaka fish (Oryzias latipes). Female medaka prefer to choose familiar mates, whereas male medaka court indiscriminately, irrespective of familiarity. We generated mutants of the oxt ligand (oxt) and receptor genes (oxtr1andoxtr2) and revealed that the oxt-oxtr1 signaling pathway was essential for eliciting female mate preference for familiar males. This pathway was also required for unrestricted and indiscriminate mating strategy in males. That is, eitheroxtoroxtr1mutation in males decreased the number of courtship displays toward novel females, but not toward familiar females. Further, males with these mutations exhibited enhanced mate-guarding behaviors toward familiar females, but not toward novel females. In addition, RNA-sequencing (seq) analysis revealed that the transcription of genes involved in gamma-amino butyric acid metabolism as well as those encoding ion-transport ATPase are up-regulated in bothoxtandoxtr1mutants only in female medaka, potentially explaining the sex difference of the mutant phenotype. Our findings provide genetic evidence that oxt-oxtr1 signaling plays a role in the mate choice for familiar individuals in a sex-specific manner in medaka fish.

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