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Chemosensory receptors are expressed primarily in sensory organs, but their expression elsewhere can permit ligand detection in other contexts that contribute to survival. The ability of sweet taste receptors to detect natural sugars, sugar alcohols, and artificial sweeteners suggests sweet taste receptors are involved in metabolic regulation in both peripheral organs and in the central nervous system. Our limited knowledge of sweet taste receptor expression in the brain, however, has made it difficult to assess their contribution to metabolic regulation. We, therefore, decided to profile the expression pattern of T1R2, a subunit specific to the sweet taste receptor complex, at the whole-brain level. Using T1r2-Cre knock-in mice, we visualized the overall distribution of Cre-labeled cells in the brain. T1r2-Cre is expressed not only in various populations of neurons, but also in glial populations in the circumventricular organs and in vascular structures in the cortex, thalamus, and striatum. Using immunohistochemistry, we found that T1r2 is expressed in hypothalamic neurons expressing neuropeptide Y and proopiomelanocortin in arcuate nucleus. It is also co-expressed with a canonical taste signaling molecule in perivascular cells of the median eminence. Our findings indicate that sweet taste receptors have unidentified functions in the brain and suggest that they may be a novel therapeutic target in the central nervous system.

Taste receptors are responsible for detecting their ligands not only in taste receptor cells (TRCs) but also in non-gustatory organs. For several decades, many research groups have accumulated evidence for such “ectopic” expression of taste receptors. More recently, some of the physiologic functions (apart from taste) of these ectopic taste receptors have been identified. Here, we summarize our current understanding of these ectopic taste receptors across multiple organs. With a particular focus on the specialized epithelial cells called tuft cells, which are now considered siblings of type II TRCs, we divide the ectopic expression of taste receptors into two categories: taste receptors in TRC-like cells outside taste buds and taste receptors with surprising ectopic expression in completely different cell types.

The sense of taste arises from the detection of chemicals in food by taste buds, the peripheral cellular detectors for taste. Although numerous studies have extensively investigated taste buds, research on neural circuits from primary taste neurons innervating taste buds to the central nervous system has only recently begun owing to recent advancements in neuroscience research tools. This minireview focuses primarily on recent reports utilizing advanced neurogenetic tools across relevant brain regions. [ABSTRACT FROM AUTHOR]

Abstract Introduction Although the risk of CVD is increased in cancer survivors, few studies have investigated the CVD risk in survivors of gastrointestinal (GI) cancer. Therefore, we evaluated the CVD risk using the 10-year atherosclerotic cardiovascular disease (ASCVD) risk score for GI cancer survivors and associated physical activity factors. Methods Using the 2014–2019 Korean National Health and Nutrition Examination Surveys, data were collected for 262 GI cancer survivors and 1,310 cancer-free controls matched at a 1:5 ratio based on age and sex. The International Physical Activity Questionnaire Short-Form was used to assess physical activity, and the Euro QoL Questionnaire 5-Dimensional Classification (EQ-5D) was used to assess the health-related quality of life. Results A multiple logistic regression analysis demonstrated a lower risk of ASCVD in GI cancer survivors than in controls (adjusted odds ratio [aOR] = 0.73, 95% confidence interval [CI] = 0.55-0.97). Moreover, the risk of having a high ASCVD score was significantly lower in individuals who performed sufficient aerobic physical activity (aOR = 0.59, 95% CI = 0.47-0.75) and those with an EQ-5D score 1 or 2 (aOR = 0.36, 95% CI = 0.20-0.65 and aOR = 0.31, 95% CI = 0.16-0.58, respectively). Conclusions This population-based study demonstrated that engaging in sufficient physical activity can reduce the ASCVD risk among GI cancer survivors.

Background/Aims We investigated the clinical practice patterns of post-polypectomy colonoscopic surveillance among Korean endoscopists. Methods In a web-based survey conducted between September and November 2021, participants were asked about their preferred surveillance intervals and the patient age at which surveillance was discontinued. Adherence to the recent guidelines of the U.S. Multi-Society Task Force on Colorectal Cancer (USMSTF) was also analyzed. Results In total, 196 endoscopists completed the survey. The most preferred first surveillance intervals were: a 5-year interval after the removal of 1–2 tubular adenomas < 10 mm; a 3-year interval after the removal of 3–10 tubular adenomas < 10 mm, adenomas ≥ 10 mm, tubulovillous or villous adenomas, ≤ 20 hyperplastic polyps < 10 mm, 1–4 sessile serrated lesions (SSLs) < 10 mm, hyperplastic polyps or SSLs ≥ 10 mm, and traditional serrated adenomas; and a 1-year interval after the removal of adenomas with highgrade dysplasia, >10 adenomas, 5–10 SSLs, and SSLs with dysplasia. In piecemeal resections of large polyps ( > 20 mm), surveillance colonoscopy was mostly preferred after 1 year for adenomas and 6 months for SSLs. The mean USMSTF guideline adherence rate was 30.7%. The largest proportion of respondents (40.8%–55.1%) discontinued the surveillance at the patient age of 80–84 years. Conclusions A significant discrepancy was observed between the preferred post-polypectomy surveillance intervals and recent international guidelines. Individualized measures are required to increase adherence to the guidelines.

Purpose Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (ARBs) are frequently employed to counteract the detrimental effects of proteinuria on glomerular diseases. However, the effects of ARBs remain poorly examined in pediatric patients with immunoglobulin A (IgA) nephropathy. Herein, we evaluated the efficacy and safety of losartan, an ARB, in pediatric IgA nephropathy with proteinuria. Methods This prospective, single-arm, multicenter study included children with IgA nephropathy exhibiting proteinuria. Changes in proteinuria, blood pressure, and kidney function were prospectively evaluated before and 4 and 24 weeks after losartan administration. The primary endpoint was the difference in proteinuria between baseline and 24 weeks. Results In total, 29 patients were enrolled and received losartan treatment. The full analysis set included 28 patients who received losartan at least once and had pre- and post-urinary protein to creatinine ratio measurements (n=28). The per-protocol analysis group included 22 patients who completed all scheduled visits without any serious violations during the study period. In both groups, the mean log (urine protein to creatinine ratio) value decreased significantly at 6 months. After 24 weeks, the urinary protein to creatinine ratio decreased by more than 50% in approximately 40% of the patients. The glomerular filtration rate was not significantly altered during the observation period. Conclusions Losartan decreased proteinuria without decreasing kidney function in patients with IgA nephropathy over 24 weeks. Losartan could be safely employed to reduce proteinuria in this patient population. ClinicalTrials.gov trial registration (NCT0223277)

Introduction The global market of flavour capsule cigarettes (FCCs) has grown significantly over the past decade; however, prevalence data exist for only a few countries. This study examined prevalence and perceptions of FCCs among adults who smoke across five countries.Methods Cross-sectional data among adults who smoked cigarettes came from the International Tobacco Control Policy Evaluation Project Surveys—Brazil (2016/2017), Japan (2021), Republic of Korea (2021), Malaysia (2020) and Mexico (2021). FCCs use was measured based on reporting one’s usual/current brand or favourite variety has flavour capsule(s). Perceptions of the harmfulness of one’s usual brand versus other brands were compared between those who used capsules versus no capsules. Adjusted logistic regression models examined correlates of FCC use.Results There were substantial differences in the prevalence of FCC use among adults who smoke across the five countries: Mexico (50.3% in 2021), Republic of Korea (31.8% in 2021), Malaysia (26.5% in 2020), Japan (21.6% in 2021) and Brazil (6.7% in 2016/2017). Correlates of FCC use varied across countries. Capsule use was positively associated with being female in Japan and Mexico, younger age in Japan, Republic of Korea and Malaysia, high education in Brazil, Japan and Mexico, non-daily smoking in Republic of Korea, and having plans to quit in Japan and Republic of Korea. There was no consistent pattern of consumer perceptions of brand harmfulness.Conclusion Our study documented the high prevalence of FCCs in some countries, pointing to the need to develop and implement regulatory strategies to control these attractive products.

The prevalence of obesity has increased significantly worldwide, and this trend is likely to continue in the coming years. There is substantial evidence that obesity plays a crucial role in the development of colorectal cancer. Epidemiological data have consistently demonstrated a correlation between obesity and colorectal cancer. Insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines, and various hormones are plausible biological mechanisms. In addition, obesity has been shown to have an impact on recurrence, treatment success, and overall survival. There are some reports, although the evidence is not conclusive, that weight loss and lifestyle changes such as dietary modification and physical activity can reduce the risk of colorectal cancer. The understanding that obesity is a potentially modifiable risk factor that can affect the incidence and prognosis of colorectal cancer is crucial knowledge that can have an impact on the prevention and treatment of the condition.

Abstract The association between ulcerative colitis (UC) and uterine cervical cancer is still unclear. To investigate cervical cancer risk in South Korean women with UC, we analyzed the Korean National Health Insurance claims data. UC was defined using both ICD-10 codes and UC-specific prescriptions. We analyzed incident cases of UC diagnosed between 2006 and 2015. Age-matched women without UC (control group) were randomly selected from the general population (1:3 ratio). Hazard ratios were calculated using multivariate Cox proportional hazard regression, and the event was defined as occurrence of cervical cancer. A total of 12,632 women with UC and 36,797 women without UC were enrolled. The incidence of cervical cancer was 38.8 per 100,000 women per year in UC patients and 25.7 per 100,000 women per year in controls, respectively. The adjusted HR for cervical cancer was 1.56 (95% CI 0.97–2.50) in the UC group with reference to the control group. When stratified by age, the adjusted HR for cervical cancer was 3.65 (95% CI 1.54–8.66) in elderly UC patients (≥ 60 years) compared to elderly control group (≥ 60 years). Within UC patients, increased age (≥ 40 years) and low socioeconomic status were associated with an increased risk of cervical cancer. The incidence of cervical cancer was found to be higher among elderly patients (≥ 60 years) with newly diagnosed UC in South Korea, compared to age-matched controls. Therefore, regular cervical cancer screening is recommended for elderly patients who have recently been diagnosed with UC.

OBJECTIVES We estimated the population prevalence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), including unreported infections, through a Korea Seroprevalence Study of Monitoring of SARS-CoV-2 Antibody Retention and Transmission (K-SEROSMART) in 258 communities throughout Korea. METHODS In August 2022, a survey was conducted among 10,000 household members aged 5 years and older, in households selected through two stage probability random sampling. During face-to-face household interviews, participants self-reported their health status, COVID-19 diagnosis and vaccination history, and general characteristics. Subsequently, participants visited a community health center or medical clinic for blood sampling. Blood samples were analyzed for the presence of antibodies to spike proteins (anti-S) and antibodies to nucleocapsid proteins (anti-N) SARS-CoV-2 proteins using an electrochemiluminescence immunoassay. To estimate the population prevalence, the PROC SURVEYMEANS statistical procedure was employed, with weighting to reflect demographic data from July 2022. RESULTS In total, 9,945 individuals from 5,041 households were surveyed across 258 communities, representing all basic local governments in Korea. The overall population-adjusted prevalence rates of anti-S and anti-N were 97.6% and 57.1%, respectively. Since the Korea Disease Control and Prevention Agency has reported a cumulative incidence of confirmed cases of 37.8% through July 31, 2022, the proportion of unreported infections among all COVID-19 infection was suggested to be 33.9%. CONCLUSIONS The K-SEROSMART represents the first nationwide, community-based seroepidemiologic survey of COVID-19, confirming that most individuals possess antibodies to SARS-CoV-2 and that a significant number of unreported cases existed. Furthermore, this study lays the foundation for a surveillance system to continuously monitor transmission at the community level and the response to COVID-19.

Rhodotorula toruloides is a non-conventional yeast with a natural carotenoid pathway. In particular, R. toruloides is an oleaginous yeast that can accumulate lipids in high content, thereby gaining interest as a promising industrial host. In this study, we isolated and taxonomically identified a new R. toruloides LAB-07 strain. De novo genome assembly using PacBio and Illumina hybrid platforms yielded 27 contigs with a 20.78 Mb genome size. Subsequent genome annotation analysis based on RNA-seq predicted 5296 protein-coding genes, including the fatty acid production pathway. We compared lipid production under different media; it was highest in the yeast extract salt medium with glycerol as a carbon source. Polyunsaturated α-linolenic acid was detected among the fatty acids, and docking phosphatidylcholine as a substrate to modeled Fad2, which annotated as Δ12-fatty acid desaturase showed bifunctional Δ12, 15-desaturation is structurally possible in that the distances between the diiron center and the carbon-carbon bond in which desaturation occurs were similar to those of structurally identified mouse stearoyl-CoA desaturase. Finally, the applicability of the extracted total lipid fraction of R. toruloides was investigated, demonstrating an increase in filaggrin expression and suppression of heat-induced MMP-1 expression when applied to keratinocytes, along with the additional antioxidant activity. This work presents a new R. toruloides LAB-07 strain with genomic and lipidomic data, which would help understand the physiology of R. toruloides. Also, the various skin-related effect of R. toruloides lipid extract indicates its potential usage as a promising cosmetic ingredient.

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: adenoma ≥10 mm in size; 3 to 5 (or more) adenomas; tubulovillous or villous adenoma; adenoma containing high-grade dysplasia; traditional serrated adenoma; sessile serrated lesion containing any grade of dysplasia; serrated polyp of at least 10 mm in size; and 3 to 5 (or more) sessile serrated lesions. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for the management of advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: (1) adenoma ≥10 mm in size; (2) 3 to 5 (or more) adenomas; (3) tubulovillous or villous adenoma; (4) adenoma containing high-grade dysplasia; (5) traditional serrated adenoma; (6) sessile serrated lesion (SSL) containing any grade of dysplasia; (7) serrated polyp of at least 10 mm in size; and (8) 3 to 5 (or more) SSLs. More studies are needed to fully comprehend the patients most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

Immunoglobulin G4 (IgG4)-related disease is a rare systemic fibroinflammatory condition characterized by elevated serum IgG4 levels and infiltration of IgG4-positive plasma cells in various organs. IgG4-related lung disease shows varied radiologic features on chest CT. Patients usually present with a solid nodule or mass mimicking lung cancer; therefore, distinguishing between IgG4-related disease and other conditions is often challenging. Additionally, co-existing radiologic findings of IgG4- related lung disease may mimic metastasis or lymphangitic carcinomatosis of the lung. We report two cases of histopathologically confirmed IgG4-related lung disease mimicking lung cancer. Chest CT revealed a solid nodule or mass with ancillary radiologic findings, which suggested lung cancer; therefore, IgG4-related lung disease was radiologically indistinguishable from lung cancer in both cases. Measurement of serum IgG4 levels and clinical evaluation to confirm involvement of various organs may be useful to establish the differential diagnosis. However, surgical biopsy evaluation is needed for confirmation.

Multiple markers are generally used in augmented reality (AR) applications that require accurate registration, such as medical and industrial fields. In AR using these markers, there are two inevitable problems: (1) geometric shape discrepancies between a real object and a virtual object, and (2) the relative positions of the markers placed on the virtual object and markers placed on the real object are not consistent. However, studies on applying multiple markers to a large object are still insufficient. Additionally, most studies did not consider these inevitable problems because the markers were subjectively placed (hereafter conventional method). In consideration of these problems, this paper proposes a method for placing multiple markers to provide accurate registration on a large object. The proposed method divides a virtual object evenly and determines the positions of multiple markers automatically using 3D interest points within the divided areas. The proposed method was validated through a performance comparison with the conventional method of subjectively placing markers, and it was confirmed to have more accurate registration.

Background/Aims: Inflammatory bowel disease (IBD) is associated with the occurrence of venous thromboembolism (VTE). However, to date, there have been few studies on the risk of VTE in Asian IBD patients. We aimed to estimate the incidence of VTE in Asian IBD patients and to determine if IBD is related to increased VTE risk. Methods: We performed a population-based cohort study between 2004 and 2015 using Korean National Health Insurance data. IBD and VTE were defined by ICD-10 codes. Incidence rates of VTE were calculated among patients with IBD and among age- and sex-matched controls. Hazard ratios were estimated using Cox regression with adjustment for multiple variables. We performed additional analyses stratifying by age, sex, Charlson comorbidity index (CCI) score, and disease type. Results: Among the 45,037 patients with IBD (IBD cohort) and 133,019 matched controls (non-IBD cohort) included in our analysis, 411 IBD patients and 641 controls developed VTE. The IBD cohort had a higher incidence rate ratio and risk of VTE than the non-IBD cohort (incidence rate ratio: 1.92 and hazard ratio: 1.93). Older age, female sex, higher CCI scores, cardiovascular disease, chronic kidney disease, use of steroids, and hospitalization were significant risk factors for VTE in patients with IBD. Conclusions: The IBD patients in this study were approximately two times more likely to develop VTE than the non-IBD individuals. Our findings support the need for thromboprophylaxis in Asian IBD patients with various factors that further increase the risk of VTE.

Background/Aims: Small rectal neuroendocrine tumors (NETs) are often managed with local resection (endoscopic or transanal excision) owing to their low risk of metastasis and recurrence. However, the clinical significance of lymphovascular invasion in resected specimens remains controversial. In this study, we aimed to analyze the frequency of and risk factors for lymph node metastasis proven by histopathologic examination after radical resection. Methods: We retrospectively reviewed the records of 750 patients diagnosed with a rectal NET at four academic medical centers in South Korea between 2001 and 2019. The frequency of histopathologically proven lymph node metastasis and the associated risk factors were analyzed for small tumors (≤1.5 cm) with lymphovascular invasion. Results: Among 750 patients, 75 had a small tumor (≤1.5 cm) with lymphovascular invasion, of whom 31 patients underwent endoscopic resection only and 44 patients underwent additional radical surgery. Among the 41 patients who underwent surgery and had available data, the rate of regional lymph node metastasis was 48.8% (20/41). In multivariate analysis, the Ki-67 index (odds ratio, 6.279; 95% confidence interval, 1.212 to 32.528; p=0.029) was an independent risk factor for lymph node metastasis. During the mean follow-up period of 37.7 months, only one case of recurrence was detected in the surgery group. The overall survival was not significantly different between radical resection and local resection (p=0.332). Conclusions: Rectal NETs with lymphovascular invasion showed a significantly high rate of regional lymph node metastasis despite their small size (≤1.5 cm).

With the ongoing coronavirus disease 2019 (COVID-19) pandemic, there is an increasing interest in the sequelae and care in recovered patients. Although the long-term sequelae of COVID-19 are still unknown, recently published reports suggest that some of the patients have persistent symptoms and show radiologic abnormalities after discharge. Herein, we present cases of four patients with previous COVID-19 infection manifesting pulmonary sequelae, including pulmonary fibrosis or organizing pneumonia pattern with persistent dyspnea after recovery.

Background/Aims: Endoscopic submucosal dissection (ESD) is a curative treatment modality for early gastric neoplasms; however, ESD can be a time-consuming process. To overcome this pitfall, we developed the one-step knife (OSK) approach, which combines an endoscopic knife and injection needle on a single sheath. We aimed to evaluate whether this approach could reduce the ESD procedure time.Methods: This single-blinded randomized multicenter trial at four tertiary hospitals from June 2019 to June 2020 included patients aged 19 to 85 years undergoing ESD. Patients were randomly assigned to two groups (OSK or conventional knife [CK]). The injection time, total procedure time, resected specimen size, submucosal fluid amount, degree of device satisfaction, and adverse events were evaluated and compared between groups.Results: Fifty-one patients were analyzed (OSK: 25 patients and CK: 26 patients). No baseline differences were observed between groups, with the exception of a higher portion of males in the OSK group. The mean injection time was significantly reduced in the OSK group (39.0 seconds) compared to that in the CK group (87.5 seconds, p

Multiple primary malignant neoplasms refer to two or more malignancies in an individual that are not related. We report a case of a 78-year-old male with concurrent breast mucinous carcinoma and extramammary lymphoma. The patient initially presented with palpable masses in the left breast and the right groin, which were pathologically confirmed after a surgical biopsy as breast mucinous carcinoma and diffuse large B-cell lymphoma, respectively. He underwent whole-body 18-fluorine deoxyglucose PET/CT before surgery, and an enhancing nodular lesion in the left lingual tonsil was found incidentally. It was later confirmed as a diffuse large B-cell lymphoma, a pathology of the same type as the right inguinal mass. Unspecified lymphadenopathies in breast cancer patients may easily be considered as metastatic lesions. However, this case suggests that lymphomas should be included in the differential diagnoses to avoid misdiagnosis and treatment delay, especially in older adult patients.

Background/Aims: Little is known about the national colonoscopy volume in Asian countries. This study aimed to assess the national colonoscopy volume in Korea over a 12-year period on the basis of a nationwide population-based database. Methods: We conducted a population-based study for colonoscopy claims (14,511,158 colonoscopies performed on 13,219,781 patients) on the basis of the Korean National Health Insurance Service database from 2002 to 2013. The 12-year national colonoscopy burden was analyzed according to patient age, patient sex, and healthcare facility type. Results: The overall volume of colonoscopy increased 8-fold over the 12-year period. The annual colonoscopic polypectomy rate significantly increased in all patient sex and age groups over the 12-years period (all p

Background/Aims Although proton pump inhibitors (PPIs) remain a mainstay for the suppression of gastric acid secretion, long-term PPI use is associated with side effects. However, the genotoxicity associated with long-term PPI use is unclear. Materials and Methods This prospective observational pilot study enrolled patients who had been on PPIs for >1 year and healthy controls from July 2015 to August 2016. The subjects completed self-report questionnaires pertaining to their drug and medical history, and only those with no medical history and a ≥2-year wash-out period (for drugs other than PPIs) were included. We collected peripheral-blood lymphocytes from long-term PPI users and healthy controls and analyzed the genotoxicity by using the cytokinesis-block micronucleus cytome assay; we also determined the fasting serum levels of pyridoxine, folate, cobalamin, and homocysteine. Results Ten long-term PPI users and 40 healthy control subjects were enrolled. The median serum pyridoxine, folate, cobalamin, and homocysteine levels were not significantly different between the groups. The median frequencies of micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (Nbuds) per 1,000 binucleated cells, in long-term PPI users and healthy controls, were 30.3 and 16.3 (P

The Big Data Research Committee of the Korean Society of Gastroenterology conducted activities and researches with three goals. First, it provides the basis for proper and cost-effective treatment of digestive diseases in Korea. Second, it carries out population- level global research by establishing a system of big data analysis related to gastroenterology. Third, it provides the members of the Korean Society of Gastroenterology with the opportunity to plan and assess the public interest related to big data. The studies published by the committee members in this paper were carried out under these objectives, and the findings are believed to have achieved the public interest goals that may be helpful in the current medical and health policy. The construction of the big data infrastructure for digestive drugs is also underway, and we expect to see meaningful results pertaining to important digestive drugs. Research using public health medical big data, such as the National Health Insurance Corporation data base, should ultimately provide a basis for reflecting public messages and policies for the public. To this end, it is necessary for Korean researchers to lead efforts to lower the barriers and to approach relevant information and opportunities using big data research.

Purpose Test equating studies in medical education have been conducted only for high-stake exams or to compare two tests given in a single course. Based on item response theory, we equated computer-based test (CBT) results from the basic medical education curriculum at the College of Medicine, the Catholic University of Korea and evaluated the validity of using fixed passing scores. Methods We collected 232 CBTs (28,636 items) for 40 courses administered over a study period of 9 years. The final data used for test equating included 12 pairs of tests. After test equating, Wilcoxon rank-sum tests were utilized to identify changes in item difficulty between previous tests and subsequent tests. Then, we identified gaps between equated passing scores and actual passing scores in subsequent tests through an observed-score equating method. Results The results of Wilcoxon rank-sum tests indicated that there were no significant differences in item difficulty distribution by year for seven pairs. In the other five pairs, however, the items were significantly more difficult in subsequent years than in previous years. Concerning the gaps between equated passing scores and actual passing scores, equated passing scores in 10 pairs were found to be lower than actual passing scores. In the other two pairs, equated passing scores were higher than actual passing scores. Conclusion Our results suggest that the item difficulty distributions of tests taught in the same course during successive terms can differ significantly. It may therefore be problematic to use fixed passing scores without considering this possibility.

Background : /Aims: Despite the many reports of colonoscopy complications worldwide, few studies have been performed at the population level in Korea. In this study, a population-based study was performed to evaluate the incidence of post-colonoscopy perforations compared to a control group. Methods : : Between January 2011 and December 2011, data for all cases (age over 45) who underwent a colonoscopy were collected from National Health Insurance Service using a random sampling method. The clinical characteristics and perforation incidence (within 30 days after the colonoscopy) of cases were identified, and cases were then compared with controls who had not undergone a colonoscopy. Results : : Among 1,380,000 subjects, 31,177 cases and 62,354 controls were identified. Perforation occurred in 14 patients (0.04%) in the case group and one patient (

This study investigated the service life prediction of fluorocarbon elastomers that are used in automotive vapor fuel hoses under thermal environments. The changes in mechanical properties such as the tensile strength, elongation, compression set (CS), and hardness according to thermal aging were investigated for two types of ternary fluoroelastomers. Destructive tests of the tensile strength and elongation showed large variations in the mechanical properties under the same condition because there is no continuity of samples. In contrast, nondestructive tests of the CS and hardness showed little variations in the mechanical properties under the same condition. The elongation, CS, and hardness were selected as the physical parameters for service life prediction as they showed a tendency according to the aging temperature, which is an accelerating factor. The effective activation energy derived using each physical parameter was 74.91–159.6 kJ mol−1, and the service life was 17.8–140 × 103 h based on B10. In this study, hardness, which has a small deviation between samples, is considered appropriate as mechanical parameter for predicting the service lifetime.

Polyamide 46 (PA46) is used in various automotive parts because of its excellent heat resistance and mechanical properties. This study aims to improve the frictional properties of PA46 using the lubricating ability of graphene. Nanocomposites are prepared via two mixing methods: Graphene powder is compounded directly with PA46 pellets through a twin-screw extruder, or PA46 powder is added to graphene dispersion for self-adsorption, and subsequently, it is dried and compounded with PA46 through the twin-screw extruder. Application of the nanocomposite in the friction field is evaluated via the pin-on-disk method. The coefficient of friction of the nanocomposite prepared by self-adsorption is lower than that of the nanocomposite prepared by direct compounding. The mechanical properties of the nanocomposite fabricated by self-adsorption are superior to those of other materials. This can be attributed to the uniform dispersion of graphene and the strong attractive force between the PA46 matrix and graphene.

Background: Anemia is a common extraintestinal manifestation of inflammatory bowel disease (IBD). However, data on the influence of anti-tumor necrosis factor-alpha (anti-TNF-α) agents and iron supplementation on anemia in patients with IBD are sparse. We assessed the effect of iron supplementation in patients with IBD initially treated with an anti-TNF-α agent. Methods: Data from 79 IBD patients who started anti-TNF-α treatment at a tertiary hospital were analyzed. The patients were divided into the anti-TNF-α ( n = 52) and anti-TNF-α with iron supplementation ( n = 27) groups. Effects on laboratory parameters, the prevalence of anemia, and disease activity were evaluated at baseline (year 0) and 1 year later. Results: The hemoglobin (Hb) level significantly increased between years 0 and 1 in both groups [12.0 ± 1.8–13.3 ± 2.0 g/dL in the anti-TNF-α group ( p

Endoscopic subureteral injection for treatment of vesicoureteral reflux (VUR) is known to be safe and efficient due to its minimal invasive nature. Being non-migratory, non-antigenic, and biocompatible, Macroplastique (Polydimethylsiloxane) is likely to be stable over time. A 5-year-old boy with a past history of subureteral administration of Macroplastique for unilateral Grade V VUR 4 years ago presented with recurrent gross and microscopic hematuria, along with suprapubic pain. On computed tomography (CT) abdomen, calcified material, suspected to be a stone, was visualized in the bladder. On diagnostic cystoscopy, calcification was seen around the orifice site where Macroplastique injection had been performed. We removed the calcific material by Holmium laser. Endoscopic subureteric implantation has several advantages, but nevertheless, vigilance is needed to detect long-term complications, especially in patients with gross or microscopic hematuria.

Purpose Rhabdomyolysis is a metabolic disorder in which the content of damaged muscle cells is released into plasma. Its manifestations include asymptomatic, myalgia, gross hematuria, and complications of acute kidney injury. Because of limited data on rhabdomyolysis in children, we performed this study to determine clinical characteristics of rhabdomyolysis in children. Methods We retrospectively reviewed the records of patients with rhabdomyolysis who were treated at the Pusan National University Children’s hospital from January 2011 to July 2016. The diagnostic criteria were serum myoglobin level of ≥80 ng/mL, exclusive of acute myocardial injury, cardiac arrest, and brain damage. Results Forty-five patients were enrolled; mean age, 116±68 months. Of these, 35 were boys and 10 were girls. Twenty-six patients experienced myalgia and 12 patients showed gross hematuria. Among these, seven patients initially had both myalgia and gross hematuria. The most common causes of rhabdomyolysis were infection, physical exertion, prolonged seizures, metabolic abnormalities, and drug addiction. Acute kidney injury (AKI) was the most common complication, followed by disseminated intravascular coagulation. Thirty-seven patients improved with sufficient fluid supply but two patients underwent hemodialysis due to deterioration of kidney function. Gross hematuria, positive occult blood test, and positive urine protein were more common in patients with AKI than in those without AKI. Conclusions In children, infection was the most common cause of rhabdomyolysis. Most patients recovered by sufficient fluid therapy. However, in severe cases, especially in patients with underlying kidney disease, hemodialysis may be necessary in the present study.

Non-infectious complications of peritoneal dialysis (PD) are relatively less common than infectious complications but are a potentially serious problem in patients on chronic PD. Here, we present a case of a non-infectious complication of PD in a 13-year- old boy on chronic PD who presented with symptoms such as hypertension, edema, dyspnea, and decreased ultrafiltration. Chest and abdominal radiography showed pleural effusion and migration of the PD catheter tip. Laparoscopic PD catheter reposition was performed because PD catheter malfunction was suspected. However, pleural effusion relapsed whenever the dialysate volume increased. To identify peritoneal leakage, computed tomography (CT) peritoneography was performed, and a defect of the peritoneum in the left lower abdomen with contrast leakage to the left rectus and abdominis muscles was observed. He was treated conservatively by transiently decreasing the volume of night intermittent PD and gradually increasing the volume. At the 2-year follow-up visit, the patient had not experienced similar symptoms. Patients on PD who present with refractory or recurrent pleural effusion that does not respond to therapy should be assessed for the presence of infection, catheter malfunction, and pleuroperitoneal communication. Thoracentesis and CT peritoneography are useful for evaluating pleural effusion, and timely examination is important for identifying the defect or fistula.

Rituximab (RTX) is a chimeric monoclonal antibody that inhibits CD20-mediated B-cell proliferation and differentiation. Several studies have examined its use in intractable nephrotic syndrome (NS) with some positive results. However, those studies examined such effects for a short-term period of 1 year, and some patients continued to relapse after a lapse in RTX treatment. Our use of RTX as a maintenance therapy (RTX injection when the CD19 cell count exceeded 100–200/μL before relapse) showed some noticeable efficacy. We used RTX in 19 patients with steroid-dependent NS (SDNS). In 12 patients treated with RTX maintenance therapy, only one relapse occurred. The mean treatment period was 23.4±12.7 months, and the mean number of RTX administrations was 3.9±1.6. The relapse rates were decreased (from 2.68/year to 0.04/year), and the drug-free period also increased (from 22.5 days/year to 357.1 days/year) during maintenance therapy. The other seven patients were treated with one cycle of RTX or additional cycles in case of relapse (non-maintenance therapy). Relapse rates were significantly decreased after RTX treatment (from 1.76/year to 0.96/year, P=0.017). The relapse-free period was 15.55±7.38 (range, 5.3–30.7) months. No severe side effects of RTX were found except for a hypersensitivity reaction such as fever and chills during its infusion. In conclusion, RTX is considered an effective and safe option to reduce the relapse rate by a single- or maintenance-interval therapy in SDNS.

Background/Aims: Although some previous studies reported that a treatment combined with mucoprotective agent could improve the eradication rate in dual or triple therapy, there are other reports that question the efficacy of combining these drugs in concomitant therapy (CoCTx). The aim of this study was to investigate the effects of rebamipide or ecabet on the Helicobacter pylori (H. pylori) eradication combined with CoCTx. Methods: We retrospectively reviewed the medical records of 277 patients with proven H. pylori infection. They were assigned to one of 3 regimens for 10 days, twice daily: (a) CoCTx (n=118): lansoprazole 30 mg, amoxicillin 1 g, metronidazole 500 mg, and clarithromycin 500 mg; (b) CoCTx+rebamipide (100 mg) (n=85); (c) CoCTx+ecabet (1 g) (n=74). Results: The baseline characteristics were not significantly different. H. pylori eradication rates were 82.2% (97/118) in CoCTx, 90.6% (77/85) in CoCTx+rebamipide, and 89.2% (66/74) in CoCTx+ecabet (p=0.17), which were statistically insignificant. Overall adverse events were more frequently reported in the CoCTx+rebamipide (50.6%. 43/85) and CoCTx+ecabet (44.6%, 33/74) groups than in the CoCTx (32.2%, 38/118) (p = 0.03) group. Drug compliances were not different between three groups (CoCTx: 95.8%, 113/118; CoCT+rebamipide: 92.9%, 79/85; CoCTx+ecabet 98.6%,73/74) (p=0.209). Multivariate analysis showed that the risk of eradication failure was significantly increased with decreased drug compliance (odds ratio 3.52, 95% confidence interval 1.00-12.32; p=0.05). Conclusions: Addition of these mucoprotective agent was not superior to CoCTx alone for eradicating H. pylori infection with frequent adverse events. Rather, drug compliance is the most related factor affecting the eradication rate. Our data suggest the importance of drug compliance over the drugs used.

Hemolytic uremic syndrome (HUS) is often encountered in children with acute kidney injury. Besides the well-known shiga toxin-producing Escherichia coli-associated HUS, atypical HUS (aHUS) caused by genetic complement dysregulation has been studied recently. aHUS is a rare, chronic, and devastating disorder that progressively damages systemic organs, resulting in stroke, end-stage renal disease, and death. The traditional treatment for aHUS is mainly plasmapheresis or plasma infusion; however, many children with aHUS will progress to chronic kidney disease despite plasma therapy. Eculizumab is a newly developed biologic that blocks the terminal complement pathway and has been successfully used in the treatment of aHUS. Currently, several guidelines for aHUS, including the Korean guideline, recommend eculizumab as the first-line therapy in children with aHUS. Moreover, life-long eculizumab therapy is generally recommended. Further studies on discontinuation of eculizumab are needed.

Gastrointestinal subepithelial tumors (SETs) are generally found during endoscopy and their incidence has gradually increased. Although the indications for the endoscopic treatment of patients with SETs remain to be established, the feasibility and safety of endoscopic dissection, including the advantages of this method compared with surgical treatment, have been validated in many studies. The development of endoscopic techniques, such as endoscopic submucosal dissection, endoscopic enucleation, endoscopic excavation, endoscopic submucosal tunnel dissection, submucosal tunnel endoscopic resection, and endoscopic full-thickness resection has enabled the removal of SETs while reducing the occurrence of complications. Here, we discuss the endoscopic treatment of patients with SETs, outcomes for endoscopic treatment, and procedure-related complications. We also consider the advantages and disadvantages of the various endoscopic techniques.

Radiofrequency ablation (RFA), a local ablative modality, is gaining acceptance for the treatment of liver malignancies. Despite a relatively low complication rate, tumor seeding resulting from RFA in hepatocellular carcinoma (HCC) treatment can occur. A 44-year-old woman was diagnosed with HCC. Spiral computed tomography (CT) revealed a 2.3 × 2.0-cm mass in the S5 segment, which was treated with RFA on May, 2005. Follow-up imaging, performed at 6-month intervals after RFA, showed complete tumor necrosis. In October 2009, CT revealed a heterogeneous mass, 5.7 cm in diameter, in the right ovary. Since the lesion was limited to the right ovary without evidence of spread, bilateral salpingo-oophorectomy was performed. Histopathology indicated that the metastatic spread from the HCC to the ovary was positive for hepatocyte-specific antigen on immunohistochemistry. The ovary is a rare site for HCC metastasis. Moreover, needle tract implantation of HCC in the ovary is very rare.

Abstract Background In an integrated curriculum, multiple instructors take part in a course in the form of team teaching. Accordingly, medical schools strive to manage each course run by numerous instructors. As part of the curriculum management, course evaluation is conducted, but a single, retrospective course evaluation does not comprehensively capture student perception of classes by different instructors. This study aimed to demonstrate the need for individual class evaluation, and further to identify teaching characteristics that instructors need to keep in mind when preparing classes. Methods From 2014 to 2015, students at one medical school left comments on evaluation forms after each class. Courses were also assessed after each course. Their comments were categorized by connotation (positive or negative) and by subject. Within each subject category, test scores were compared between positively and negatively mentioned classes. The Mann-Whitney U test was performed to test group differences in scores. The same method was applied to the course evaluation data. Results Test results for course evaluation showed group difference only in the practice/participation category. However, test results for individual class evaluation showed group differences in six categories: difficulty, main points, attitude, media/contents, interest, and materials. That is, the test scores of classes positively mentioned in six domains were significantly higher than those of negatively mentioned classes. Conclusions It was proved that individual class evaluation is needed to manage multi-instructor courses in integrated curricula of medical schools. Based on the students’ extensive feedback, we identified teaching characteristics statistically related to academic achievement. School authorities can utilize these findings to encourage instructors to develop effective teaching characteristics in class preparation.

Systemic lupus erythematosus (SLE) is characterized by various symptoms and multi-organ involvement. Hypophosphatemia has been described in several diseases accompanied with systemic inflammation. However, hypophosphatemia has rarely been described in SLE patients, especially in those without nephritis. We report the case of a 13-year-old girl with SLE who developed hypophosphatemia without renal involvement. Her hypophosphatemia was caused by renal loss of phosphorus and persisted for 7 months. It improved as her complement levels increased. Therefore, hypophosphatemia may be related to disease activity in SLE patients.

Background/AimsThe increased resistance of Helicobacter pylori to antibiotics has increased the need to develop new treatments for this bacterium. The aim of our study was to identify new drugs with anti-H. pylori activity.Methods : We screened a small molecule library—the library of pharmacologically active compounds (LOPAC), which includes 1,280 pharmacologically active compounds—to identify inhibitors of H. pylori growth. The minimal inhibitory concentrations (MICs) of antibiotics against multidrug-resistant H. pylori strains were determined using the agar dilution method.Results : We identified diphenyleneiodonium (DPI) as a novel anti-H. pylori agent. The MIC values for DPI were

Background/AimsThe use of laparoscopic adjustable gastric banding (LAGB) is increasing proportionally with the obesity epidemic. However, some postoperative complications have been highlighted as major problems associated with LAGB. There is no consensus concerning the endoscopic management of these adverse events. The aim of this study was to retrospectively review the feasibility and effectiveness of endoscopic treatment for LAGB complications.Methods : We retrospectively evaluated 352 patients who underwent LAGB between 2011 and 2015. LAGB-associated complications developed in 26 patients (7.4%). This study involved six patients (1.7%) who received endoscopic treatment.Results : Types of LAGB-induced complications in our series included intragastric migration (n=3), gastric leaks (n=2), and gastric fistulas (n=1). The endoscopic treatment of these complications was successful in four of the six patients. Endoscopic band removal was successful in two patients. All gastric leaks were successfully closed via an endoscopic procedure. In two cases (intragastric migration and gastric fistula), endoscopic treatment was not sufficient, and surgery was performed.Conclusion : sEndoscopic procedures afforded acceptable treatment of band migration and gastric leaks after LAGB. However, the results were poor in patients with gastric fistula.

Tumor lysis syndrome is a serious complication of malignancy, resulting from the massive and rapid release of cellular components into the blood. Generally, it occurs after initiation of chemotherapy. The onset of spontaneous tumor lysis syndrome (STLS) before anti-cancer treatment is rare and occurs mostly in Burkitt lymphoma and non-Hodgkin’s lymphoma. There are only a few case reports in children. Here, we report a case of STLS secondary to T-cell acute lymphoblastic leukemia (ALL), which presented with urinary stone and subsequent acute kidney injury with severe hyperuricemia. Occult malignancy should be considered in case of unexplained acute kidney injury with extreme hyperuricemia.

Purpose Using standard mammographic phantom images, we compared the image quality obtained between a mammography dedicated 5 megapixel monitor (5M) and a UHD 4K (4K) monitor with digital imaging and communications in medicine display, to investigate the possibility of clinical application of 4K monitors. Materials and Methods Three different exposures (autoexposure, overexposure and underexposure) images of mammographic phantom were obtained, and six radiologists independently evaluated the images in 5M and 4K without image modulation, by scoring of fibers, groups of specks and masses within the phantom image. The mean score of each object on both monitors was independently analyzed, using t-test and interobserver reliability by intraclass correlation coefficient (ICC) of SPSS. Results The overall mean scores of fiber, group of specks, and mass in 5M were 4.25, 3.92, and 3.28 respectively, and scores obtained in 4K monitor were 3.81, 3.58, and 3.14, respectively. No statistical difference was seen in scores of fiber and mass between the two monitors at all exposure conditions, but the score of group of specks in 4K was statistically lower in the overall (p = 0.0492) and in underexposure conditions (p = 0.012). The ICC for interobserver reliability was excellent (0.874). Conclusion Our study suggests that since the mammographic phantom images are appropriate with no significant difference in image quality observed between the two monitors, the 4K monitor could be used for clinical studies. Since this is a small preliminary study using phantom images, the result may differ in actual mammographic images, and subsequent investigation with clinical mammographic images is required.

Deinoxanthin, a xanthophyll derived from Deinococcus species, is a unique organic compound that provides greater antioxidant effects compared to other carotenoids due to its superior scavenging activity against singlet oxygen and hydrogen peroxide. Therefore, it has attracted significant attention as a next-generation organic compound that has great potential as a natural ingredient in a food supplements. Although the microbial identification of deinoxanthin has been identified, mass production has not yet been achieved. Here, we report, for the first time, the development of an engineered extremophilic microorganism, Deinococcus radiodurans strain R1, that is capable of producing deinoxanthin through rational metabolic engineering and process optimization. The genes crtB and dxs were first introduced into the genome to reinforce the metabolic flux towards deinoxanthin. The optimal temperature was then identified through a comparative analysis of the mRNA expression of the two genes, while the carbon source was further optimized to increase deinoxanthin production. The final engineered D. radiodurans strain R1 was able to produce 394 ± 17.6 mg/L (102 ± 11.1 mg/g DCW) of deinoxanthin with a yield of 40.4 ± 1.2 mg/g sucrose and a productivity of 8.4 ± 0.2 mg/L/h from 10 g/L of sucrose. The final engineered strain and the strategies developed in the present study can act as the foundation for the industrial application of extremophilic microorganisms.

PurposeThis study investigated the prevalence and risk factors associated with vitamin D deficiency in children.MethodsWe analyzed the medical records of 330 patients from the age of 6 to 12, who visited the endocrinology clinic of the Department of Pediatrics at Pusan National University Hospital, from September, 2013 to May, 2014. According to their serum 25-hydroxyvitamin D (25(OH)D) levels, the patients were grouped into either the deficiency group (25(OH)D

Primary mediastinal leiomyoma is an extremely rare benign tumor of smooth muscle. Most common radiographic appearance is a well circumscribed heterogeneous solid mass. We reported a case of giant cyst-like lesion at the middle mediastinum, which was pathologically confirmed as a primary mediastinal leiomyoma.