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Oversampling is an efficient technique in dealing with class-imbalance problem. It addresses the problem by reduplicating or generating the minority class samples to balance the distribution between the samples of the majority and the minority class. Synthetic minority oversampling technique (SMOTE) is one of the typical representatives. During the past decade, researchers have proposed many variants of SMOTE. However, the existing oversampling methods may generate wrong minority class samples in some scenarios. Furthermore, how to effectively mine the inherent complex characteristics of imbalanced data remains a challenge. To this end, this paper proposes a parameter-free data cleaning method to improve SMOTE based on constructive covering algorithm. The dataset generated by SMOTE is first partitioned into a group of covers, then the hard-to-learn samples can be detected based on the characteristics of sample space distribution. Finally, a pair-wise deletion strategy is proposed to remove the hard-to-learn samples. The experimental results on 25 imbalanced datasets show that our proposed method is superior to the comparison methods in terms of various metrics, such as F-measure, G-mean, and Recall. Our method not only can reduce the complexity of the dataset but also can improve the performance of the classification model. INDEX TERMSImbalanced data, SMOTE, oversampling, constructive covering algorithm, data cleaning.

Abstract Background and Aims The aim of this study was to investigate the metabolic profile of mesenteric adipocytes and the correlations between key metabolic changes and local inflammation in the context of Crohn’s disease [CD]. Methods Metabolic dysfunction was shown to be regulated by fatty acid desaturase-2 [FADS2], through metabolomics and functional analyses of mesenteric adipose tissue biopsies and primary mesenteric adipocytes isolated from surgical specimens collected from CD patients and control subjects. FADS2 was overexpressed in vitro and in vivo using a lentiviral vector and an adeno-associated virus [AAV], respectively. The interaction between mesenteric adipocytes and inflammation responses was evaluated by establishing a cell coculture system and a FADS2-AAV treated animal model; 3T3-L1 cells were used to elucidate the mechanism underlying FADS2 deregulation. Results We observed significant changes in the levels of metabolites involved in the multi-step synthesis of long-chain polyunsaturated fatty acids [PUFAs]. Gas chromatography analysis revealed impaired desaturation fluxes towards the n-6 and n-3 pathways, which are associated with reduced FADS2 activity in human mesentery tissue. Decreased FADS2 expression at both mRNA and protein levels was confirmed in surgical specimens. The restoration of FADS2 expression, which allows for the endogenous conversion of n-3 fatty acids into proresolving lipid mediators, resulted in a significant reduction in pro-inflammatory macrophage infiltration and attenuated expression of inflammatory cytokines or adipokines. Conclusions These findings indicate that impaired fatty acid desaturation and lipid mediator imbalance within mesenteric adipose tissue contributes to chronic inflammation in CD. The therapeutic role of FADS2 may lead to improved CD treatment.

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Background. Bone loss is common in patients with inflammatory bowel disease (IBD). The aim of the present study was to determine the prevalence of metabolic bone disease in patients newly diagnosed with IBD and to identify the risk factors for bone loss over time. Methods. We performed a retrospective, both cross-sectional and longitudinal, study to extract the risk factors of bone loss (including osteopenia and osteoporosis) in patients newly diagnosed with IBD, using dual-energy X-ray absorptiometry (DXA). Results. A total of 639 patients newly diagnosed with IBD that had at least one DXA were included in the cross-sectional study. Osteopenia and osteoporosis were diagnosed in 24.6% and 5.4% of patients, respectively. Age at diagnosis, body mass index, and serum phosphorus were identified as independent factors associated with bone loss at baseline. A total of 380 of the 639 IBD patients (including 212 CD patients and 168 UC patients) with at least a second DXA scan were included in the longitudinal study. 42.6% of the patients presented a worsening of bone loss in the follow-up study. Menopause, albumin, and use of corticosteroids were identified as independent factors associated with worsening of bone loss. Conclusions. Metabolic bone disease is common in IBD patients, and there is a significant increase in prevalence of bone loss over time. Postmenopausal female, malnourished patients, and those requiring corticosteroid treatment are at risk for persistent bone loss. Therefore, BMD measurements and early intervention with supplementation of calcium and vitamin D are recommended in IBD patients with high-risk factors.

BACKGROUND: The perioperative behavior of fecal calprotectin and whether it predicts early postoperative endoscopic recurrence of Crohn’s disease are unknown. OBJECTIVE: We aimed to compare the perioperative profiles of fecal calprotectin between patients with Crohn’s disease and patients without Crohn’s disease undergoing intestinal resection and to identify the association between consecutive fecal calprotectin levels and endoscopic recurrence 3 months after surgery in patients with Crohn’s disease. DESIGN: This was a prospective observational study. SETTINGS: This study was conducted in a tertiary referral hospital. PATIENTS: One hundred fourteen consecutive patients (90 Crohn’s disease, 24 non-Crohn’s disease) who underwent resection were recruited. MAIN OUTCOME MEASURES: Univariate and multivariate analyses were performed to identify variations and risk factors. The predictive accuracy of the possible predictors was assessed by using receiver operating characteristic curves. RESULTS: The fecal calprotectin levels on preoperative day 14 and postoperative days 14, 21, 28, 60, and 90 were higher in the Crohn’s disease group than they were in non-Crohn’s disease group (p < 0.05). Twenty patients (22.2%) developed endoscopic recurrence 3 months after resection. The trend for fecal calprotectin change (Δfecal calprotectin) from preoperative day 14 to postoperative day 14 was opposite in the recurrence and nonrecurrence groups. Multivariate analysis showed that this change was a predictive factor of early endoscopic recurrence (p < 0.05). ΔFecal calprotectin was more accurate at predicting early endoscopic recurrence than was fecal calprotectin at single time points with a cutoff value of 240 μg/g. LIMITATIONS: This is a single-center trial with a limited cohort of patients. CONCLUSIONS: The perioperative fecal calprotectin levels were higher in patients with Crohn’s disease than they were in the control group. The change in fecal calprotectin levels from preoperative day 14 to postoperative day 14 could serve as a practical predictive index for early postoperative endoscopic recurrence. See Video Abstract at http://links.lww.com/DCR/A796.

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