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BACKGROUND AND AIM Endoscopic resection is highly effective treatment option for rectal neuroendocrine tumors (NETs) as they usually present as small localized tumors. However, there are no well-established surveillance strategies following endoscopic resection. We established our own protocol for the surveillance of rectal NETs after endoscopic resection since 2013. This study aimed to assess the outcome and to optimize the surveillance strategies after endoscopic resection. METHODS We retrospectively analyzed the data of patients with endoscopically treated rectal NETs between January 2013 and April 2018 at Samsung Medical Center. We analyzed 337 patients with a median follow-up duration of 35.0 months (min-max: 12.0-88.3). RESULTS A total of 329 (97.6%) patients had tumors ≤ 1 cm in size, and eight (2.4%) patients had tumors > 1 cm in diameter. Synchronous rectal NETs were diagnosed in nine (2.7%) patients. Thirteen (3.9%) patients were identified as having positive resection margins. Regardless of the salvage treatment, none of these patients developed recurrence. Metachronous rectal NETs were diagnosed in nine (2.7%) patients. Metachronous lesions were associated with the number of synchronous lesions at initial diagnosis (P

Background and aim Previous studies suggested an association between Helicobacter pylori infection and osteoporosis; however, large-scale longitudinal studies are lacking to elucidate this association. Methods A cohort study of 10 482 women without osteoporosis at baseline who participated in a repeated health-screening examination including an H. pylori-specific immunoglobulin G antibody test was conducted to evaluate the association between H. pylori and osteoporosis development. Osteoporosis was diagnosed using dual-energy X-ray absorptiometry. Results During the 77 515.3 person-years of follow-up, women with H. pylori infection had a higher rate of incident osteoporosis than those who were uninfected. In a multivariable model adjusted for age, body mass index (BMI), menopausal status, smoking status, regular exercise, comorbidities (including hypertension, diabetes mellitus, dyslipidemia, stroke, or ischemic heart disease), and concomitant medications, the hazard ratio (HR) for incident osteoporosis in women with H. pylori infection compared with that in women without infection was 1.23 (95% confidence interval [CI], 1.03-1.45). The association between H. pylori and osteopenia development was also evident. In the multivariable analysis, menopause (HR, 1.68; 95% CI, 1.31-2.16) and increasing age (HR, 1.07; 95% CI, 1.06-1.08) were identified as significant risk factors for osteoporosis, whereas higher BMI (HR, 0.84; 95% CI, 0.81-0.87) was a protective factor for the risk of osteoporosis. Conclusions In this cohort study, H. pylori infection was associated with an increased risk of osteoporosis, independent of risk factors and confounding factors.

BACKGROUND The association between NUDT15 polymorphisms and thiopurine-induced leucopenia is well known. AIM To investigate the association between NUDT15 polymorphisms and time-to-leucopenia in paediatric patients with inflammatory bowel disease (IBD) receiving azathioprine and to determine the relationship between NUDT15 polymorphisms and 6-thioguanine nucleotide (6-TGN) levels. METHODS This retrospective observational study included Korean paediatric patients with IBD who were treated with azathioprine and underwent NUDT15 and TPMT genotyping. Azathioprine doses were adjusted by regular thiopurine metabolite monitoring. Factors associated with time-to-leucopenia and the relationship between NUDT15 polymorphisms and 6-TGN levels were analysed. RESULTS Among the 167 patients included, leucopenia was observed in 16% (19/119), 44% (20/45) and 100% (3/3) of the NUDT15 normal, intermediate and poor metabolisers respectively (P

AIMS: This study explores the effects of various genetic polymorphisms in candidate genes on thiopurine metabolism and toxicity in adult patients with Crohn's disease in Korea. METHODS: A total of 131 adult patients with Crohn's disease receiving thiopurine treatment were included. The TPMT and NUDT15 genes and an additional 116 genetic polymorphisms (in 40 genes and 3 intergenic locations) were screened for genotyping. Among the polymorphisms screened, 91 genetic polymorphisms (in 34 genes and 3 intergenic locations) in addition to TPMT and NUDT15 genotypes were included for statistical analyses to investigate their effects on thiopurine metabolites and adverse outcomes (leukopenia, hepatotoxicity, gastrointestinal intolerance, skin rash and alopecia). RESULTS: The median duration of thiopurine treatment was 47.0 months (range 6.0–153.4 months). Patient sex, maintenance dose of thiopurine, and use of anti‐tumour necrosis factor agents were associated with thiopurine metabolite concentrations (P < .05). In the univariate analysis, the TPMT genotype was associated with 6‐thioguanine level (P < .05), although the significance of this did not remain in multivariate analysis. Genetic polymorphisms in the ATIC (rs3821353 and rs16853834), IMPDH2 (rs11706052) and ITPA (rs6139036) genes were associated with thiopurine metabolism (P < .05). Genetic polymorphisms in the ABCC5 (rs8180093) and NUDT15 genotypes were associated with leukopenia (P < .05). CONCLUSION: The results of this study may help clinicians to understand the effects of other various polymorphisms in addition to TPMT and NUDP15 in thiopurine metabolism for management of Crohn's disease patients.

BACKGROUND AND AIM Little is known regarding the exact burden of inflammatory bowel disease (IBD) in Asian countries because previous epidemiologic studies were hospital based. We aimed to develop and validate an operational definition of IBD cases from health insurance claims data and to examine the epidemiological features of IBD in Korea. METHODS We analyzed stratified sample data from the Korean Health Insurance Review and Assessment (2010-2016) database using 12 different definitions and applied the best definition to the entire (2007-2016) dataset. RESULTS The definition that combined the International Classification of Disease 10th revision code with IBD-specific medications had the best performance characteristics among the 12 tested definitions. During the 8-year study period, IBD prevalence increased from 25 345 in 2009 to 47 444 in 2016. Over that period, the prevalence of Crohn's disease increased 1.9-fold (from 16.0/100 000 in 2009 to 29.6/100 000 in 2016) and that of ulcerative colitis increased 1.6-fold (from 41.4/100 000 in 2009 to 66.0/100 000 in 2016). Similarly, the estimated incidence of Crohn's disease also increased 1.2-fold (from 2.4 to 2.9 per 100 000) and that of ulcerative colitis rose 1.3-fold (from 4.0 to 5.3 per 100 000). During the study period, the predominant increase in IBD incidence was among younger individuals, especially those aged

Background Although a higher risk of other immune-mediated diseases has been reported in inflammatory bowel disease (IBD) patients, the risk factors of immune-mediated diseases development and the effect of concomitant immune-mediated diseases on outcomes remain poorly defined. Aim To determine the risk factors of incident immune-mediated diseases and the impact of comorbid immune-mediated diseases on outcomes in IBD. Methods Using the National Health Insurance claims data for the entire Korean population, we identified 35 581 IBD patients without immune-mediated diseases and 595 IBD patients with immune-mediated diseases from 2012 to 2013, and follow-up until 2016. We selected four controls by age and sex for comparing with cases. Results A total of 35 581 IBD patients without immune-mediated diseases and 142 324 matched controls without immune-mediated diseases were followed from 2014 to 2016 and of these 239 IBD patients and 357 controls developed immune-mediated disease. The overall immune-mediated diseases risk was higher in IBD patients (HR, hazard ratio, 2.47; 95% confidence interval, CI, 2.09-2.91). In a nested case-control study of the IBD cohort, adult patients aged ≥20 years and frequent hospitalisation ≥1 per year were independent risk factors for incident immune-mediated diseases, in contrast, 5-aminosalicylic acid (5-ASA) use had protective effect (odds ratio, 0.61; 95% CI, 0.41-0.90) for developing immune-mediated diseases. In addition, IBD patients with another immune-mediated disease had an increased risk of needing anti-TNF-α agent (HR, 2.40; 95% CI, 2.02-2.84) and developing acute flare (HR, 1.76; 95% CI, 1.37-2.26). Conclusions The incidence of immune-mediated diseases in IBD patients was higher than that of non-IBD population. 5-ASA use may reduce this risk.

Objectives Periodontitis is a highly prevalent chronic inflammatory disease that results in destruction of tooth-supporting structures followed by tooth-loss. Until now, periodontitis has been regarded to be initiated by bacterial infection followed by aberrant host response. Although increasing evidence suggests a strong association between oxidative stress and periodontitis, precise molecular mechanism has been left unanswered. In this study, we investigated roles of SOD2, the main antioxidant enzyme maintaining reactive oxygen species (ROS) homeostasis, under inflammatory conditions. Methods We computationally analyzed SOD2 expression in periodontitis. To confirm this data, immunoblot assay was performed with samples from periodontitis patients. The cellular mechanism of change in SOD2 expression was identified through immunoblot assay and immunofluorescence. To evaluate the molecular function of SOD2, we generated SOD2-deficient cells by utilizing the CRISPR/Cas9 system. Results We first determined that SOD2 expression was significantly increased in periodontitis. We also confirmed that SOD2 expression was upregulated through the NF-κB pathway when the inflammatory signal was stronger and extended. Gene manipulation against SOD2 through the CRISPR/Cas9 system showed that the absence of SOD2 increased production of NLRP3 inflammasome components. Conclusions Our study demonstrates that intracellular SOD2 has a protective role by suppressing NLRP inflammasome-caspase-1-IL-1β axis under inflammatory conditions.

Background and aim Sarcopenia is a pathological condition characterized by the progressive loss of muscle mass and increased amount of visceral fat. Recent evidence has revealed that sarcopenia is associated with certain diseases. However, the impact of sarcopenia on colorectal neoplasia has not been documented clearly. We studied the association between sarcopenia and advanced colorectal neoplasia in a large screening population. Methods This cross-sectional study included 14 024 asymptomatic adults who underwent first-time screening colonoscopy. Sarcopenia (class II) was defined as an appendicular skeletal muscle mass (ASM)/bodyweight (%) value more than two standard deviations below the mean for healthy young adults. ASM was estimated using bioelectrical impedance analysis. Results In a multivariable model adjusted for age, sex, obesity (body mass index ≥ 25), smoking status, alcohol intake, regular exercise, and family history of colorectal cancer, the odds ratio (OR) for advanced colorectal neoplasia on comparing participants with sarcopenia (class II) to those without sarcopenia (class I + II) was 1.52 (95% confidence interval [CI], 1.23-1.86). Further adjustment for metabolic parameters attenuated this association, but the association was still significant (OR, 1.34; 95% CI, 1.07-1.68). Furthermore, the multivariable (traditional risk factors)-adjusted OR associated with a 1% decrease on the introduction of ASM/weight% as a continuous variable in regression models was 1.04 (95% CI, 1.01-1.07) for advanced colorectal neoplasia. Conclusions Our findings indicate that sarcopenia is significantly and progressively associated with the risk of advanced colorectal neoplasia. This association might be explained by metabolic factors that could be potential mediators of the effect of sarcopenia.

Summary Numerous studies have investigated the association between education and overweight/obesity. Yet less is known about the relative importance of causation (i.e. the influence of education on risks of overweight/obesity) and selection (i.e. the influence of overweight/obesity on the likelihood to attain education) hypotheses. A systematic review was performed to assess the linkage between education and overweight/obesity in prospective studies in general populations. Studies were searched within five databases, and study quality was appraised with the Newcastle–Ottawa scale. In total, 31 studies were considered for meta-analysis. Regarding causation (24 studies), the lower educated had a higher likelihood (odds ratio: 1.33, 1.21–1.47) and greater risk (risk ratio: 1.34, 1.08–1.66) for overweight/obesity, when compared with the higher educated. However, these associations were no longer statistically significant when accounting for publication bias. Concerning selection (seven studies), overweight/obese individuals had a greater likelihood of lower education (odds ratio: 1.57, 1.10–2.25), when contrasted with the non-overweight or non-obese. Subgroup analyses were performed by stratifying meta-analyses upon different factors. Relationships between education and overweight/obesity were affected by study region, age groups, gender and observation period. In conclusion, it is necessary to consider both causation and selection processes in order to tackle educational inequalities in obesity appropriately.

Recently reported genome-wide association studies have identified more than 20 common low-penetrance colorectal cancer (CRC) susceptibility loci. Recent studies have reported that copy number variations (CNVs) are considered important human genomic variants related to cancer, while the contribution of CNVs remains unclear. We performed array comparative genomic hybridization (aCGH) in 36 CRC patients and 47 controls. Using breakpoint PCR, we confirmed the breakpoint of the PKD1L2 deletion region. High frequency of PKD1L2 CNV was observed in CRC cases. We validated the association between PKD1L2 variation and CRC risk in 1,874 cases and 2,088 controls (OR=1.44, 95% CI=1.04-1.98, P=.028). Additionally, PKD1L2 CNV is associated with increased CRC risk in patients younger than 50 years (OR=2.14, 95% CI 1.39-3.30, P=5.8x10-4). In subgroup analysis according to body mass index (BMI), we found that the CN loss of PKD1L2 with BMI above or equal to 25 exhibited a significant increase in CRC risk (OR=2.29, 95% CI 1.29-4.05, P=.005). PKD1L2 CNV with BMI above or equal to 25 and age below 50 is associated with a remarkably increased risk of colorectal cancer (OR=5.24, 95% CI 2.36-11.64, P= 4.8x10-5). Moreover, we found that PKD1L2 variation in obese patients (BMI>=25) was associated with poor survival rate (P=.026). Our results suggest that the common PKD1L2 CNV is associated with CRC, and PKD1L2 CNV with high BMI and/or age below 50 exhibited a significant increased risk of CRC. In obese patients, PKD1L2 variation was associated with poor survival. This article is protected by copyright. All rights reserved.

Background and aim The role of diabetes mellitus as a risk factor for gastric cancer has been controversial. We studied the association between diabetic biomarkers and the risk of gastric cancer and whether these associations depend on cancer location. Methods In this retrospective cohort study with subjects with negative initial esophagogastroduodenoscopy findings (n = 23 218) during a routine health checkup, we measured fasting glucose and insulin levels, calculated the homeostatic model assessment insulin resistance (HOMA-IR) values, and analyzed the risk of gastric cancer in relation to diabetic biomarker tertiles and the presence of diabetes mellitus. Results The incidence rate of gastric cancer was 9.7 per 10 000 person-years during the mean 6.8-year follow up. Patients with diabetes, higher fasting glucose levels, or higher HOMA-IR levels were older; men, current smokers, and heavy alcohol consumers represented larger proportions of these groups. They also had high body mass index and hemoglobin A1c more often. In the multivariate-adjusted Cox regression analyses, the incidence of gastric cancer was not significantly associated with diabetes mellitus or higher diabetic biomarker levels. Compared with normal glucose levels, lower glucose levels were significantly associated with an increased risk of distal gastric cancer. The hazard ratio for fasting glucose level tertile 1 was 2.39 (95% confidence interval, 1.48-3.85) (reference, tertile 2). Lower glucose levels were not associated with a risk of proximal gastric cancer, compared with a normal glucose level. Conclusions Our findings suggest that fasting glucose levels have a different effect on distal and proximal gastric cancers.

We constructed simple model that characterizes overall behaviors of PDP power and luminance using five measurable indexes. By characterizing various design factors by measurable indexes, we can easily compare power consumptions of them on the conditions of same luminance and same video signal input. This comparison gives deep insight in reducing power consumption through overall optimization of cell structures, materials, gas, and driving schemes.

An ultra large-sized flexible plasma display panel for wall display with high luminous efficacy is proposed. It will be composed of three electrodes type unit cell whose discharge gap can be varied from 1 to 5 cm. The visible discharge efficiency increased from 30 lm/W to 76 lm/W as the electrode gap increased from 1 to 5 cm with Ne-Xe (4 %) mixture. Independent control of each cell in a multi-cell panel was demonstrated. It is suggested that a highly efficient, ultra large sized, flexible plasma display with sizes bigger than 300 inches diagonal can be realized if the developed cell is used as the basic pixel.

The characteristics of Mercury-free, flat light source has been studied. An electrodeless, Dielectric Barrier Discharge (DBD) was used to generate the plasma using Ne-Xe mixture gas of relatively low gas pressure in a 4 inch diagonal size of flat panel. Deployment of a special electrode structure resulted in discharges with high luminous efficiency with a wide driving voltage margin without contraction. When the gas and driving conditions were optimized, the luminous efficiency could be as high as more than 100 lm/W and the voltage margin a few hundred volts. The electrode structure was designed such that any hypersized flat light source can be made by a simple repeated connection of the base unit.

Enclosed barrier rib structure whose aspect ratio is 4:3 (horizontal to vertical) has shown an extraordinary high luminous efficiency increase compared to that of the conventional stripe cell structure (1:3 aspect ratio) when high Xe content gas or sustain auxiliary pulses are applied. The major reason we concluded through the numerical simulation to explain this phenomenon is the differences in the plasma loss to the barrier ribs. We also carried out experiments applying sustain auxiliary pulses to high Xe content test panels with green phosphor to obtain 6.7lm/W, 2800cd/m2 under continuous sustaining condition of 50kHz pulses.