Soonchunhyang University Hospital Cheonan

Oxidative stress has been implicated in the pathogenesis of Alzheimer's disease (AD). Mitochondrial dysfunction is linked to oxidative stress and reactive oxygen species (ROS) in neurotoxicity during AD. Impaired mitochondrial metabolism has been associated with mitochondrial dysfunction in brain damage of AD. While the role of NADPH oxidase 4 (NOX4), a major source of ROS, has been identified in brain damage, the mechanism by which NOX4 regulates ferroptosis of astrocytes in AD remains unclear. Here, we show that the protein levels of NOX4 were significantly elevated in impaired astrocytes of cerebral cortex from patients with AD and APP/PS1 double-transgenic mouse model of AD. The levels of 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA), a marker of oxidative stress-induced lipid peroxidation, were significantly also elevated in impaired astrocytes of patients with AD and mouse AD. We demonstrate that the over-expression of NOX4 significantly increases the impairment of mitochondrial metabolism by inhibition of mitochondrial respiration and ATP production via the reduction of five protein complexes in the mitochondrial ETC in human astrocytes. Moreover, the elevation of NOX4 induces oxidative stress by mitochondrial ROS (mtROS) production, mitochondrial fragmentation, and inhibition of cellular antioxidant process in human astrocytes. Furthermore, the elevation of NOX4 increased ferroptosis-dependent cytotoxicity by the activation of oxidative stress-induced lipid peroxidation in human astrocytes. These results suggest that NOX4 promotes ferroptosis of astrocytes by oxidative stress-induced lipid peroxidation via the impairment of mitochondrial metabolism in AD.

Carbon-based nanomaterials emerge as promising platforms for theranostic applications in disease treatment and tissue repair.

BACKGROUND: Procedural results for percutaneous coronary intervention (PCI) in coronary vessels with chronic total occlusion (CTO) have improved in recent years, and PCI strategies have moved toward more complete revascularization with more liberal use of CTO-PCI. However, evidence evaluating CTO-PCI is limited to observational studies and small clinical trials. METHODS: In this open-label, multicenter, randomized, noninferiority trial, PCI-eligible patients were assigned to receive either 1 of 2 strategies: PCI or no PCI for the qualifying de novo CTO lesion with the option for PCI of obstructive non-CTO lesions at the discretion of the operator. The primary end point was a composite of death, myocardial infarction, stroke, or any revascularization. Health-related quality of life was assessed at baseline and at 1, 6, 12, 24, and 36 months. Because of slow recruitment, the trial was stopped before completion of the 1284 planned enrollments. RESULTS: Between March 2010 and September 2016, 834 patients were randomly assigned to the CTO-PCI (n=417) or no CTO-PCI (n=398) strategy. Among the patients assigned to the no CTO-PCI strategy, 78 (19.6%) crossed over to receive staged CTO-PCI within 3 days of randomization. The overall CTO-PCI success rate was 90.6%. Serious nonfatal complications associated with CTO-PCI occurred in 3 patients (1 stroke, 1 cardiac tamponade, and 1 patient with recurrent episodes of ventricular tachyarrhythmia induced by intracoronary thrombus). Approximately half of the patients in each group underwent PCI for an average of 1.3 non-CTO lesions, resulting in a comparable residual SYNTAX score (Synergy Between PCI With TAXUS and Cardiac Surgery; 3.7±5.4 versus 4.0±5.9, P=0.42) confined to non-CTO vessels. During a median follow-up of 4.0 years (interquartile range, 2.4 to 5.1 years), there was no significant difference between the CTO-PCI and the no CTO-PCI strategies in the incidence of the primary end point (22.3% versus 22.4%, hazard ratio, 1.03; 95% CI, 0.77 to 1.37; P=0.86). Both CTO-PCI and no CTO-PCI strategy were associated with significant improvements but without between-group differences in disease-specific health status that was sustained through 36 months. CONCLUSIONS: CTO-PCI was feasible with high success rates. There was no difference in the incidence of major adverse cardiovascular events with CTO-PCI versus no CTO-PCI, but the study was limited by low power for clinical end points and high crossover rates between groups. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01078051.

A new high-capacity electrode material made from only earth-abundant elements.

OBJECTIVES: Although some studies have shown that the quantitative, immunochemical fecal occult blood test (FOBT) (qFIT) has better performance characteristics than the standard guaiac-based FOBT (GT) for identifying advanced colorectal neoplasia (ACRN), there is limited information on test performance of these tests in average-risk populations. METHODS: Seven hundred seventy consecutive average-risk patients from four centers who were undergoing screening colonoscopy also provided stool samples. Stool specimens from three consecutive bowel movements were applied to a hemoccult II test card (Beckman Coulter, Fullerton, CA) and OC-SENSA MICRO (Eiken Chemical, Tokyo, Japan) sampling probes at the same time. We measured the diagnostic value of the qFIT for detecting an ACRN by using three criteria: sensitivity, specificity, and likelihood ratios. A receiver operating characteristic curve for determining the qFIT cutoff values and the number of tests that best discriminated between ACRNs and other findings were determined. RESULTS: Seventy-eight ACRNs were identified during colonoscopy. At all hemoglobin thresholds, the sensitivity of the qFIT was higher than that of the GT for cancer or ACRN. The sensitivity and specificity of the GT for detecting advanced adenomas, cancer, and ACRNs were 13.6%/92.4%, 30.8%/92.4%, and 16.7%/92.9%, respectively. Using the 100 ng/ml cut point and three-sample qFIT results, the sensitivity and specificity of the qFIT for detecting advanced adenomas, cancer, and ACRNs were 33.9%/90.6%, 84.6%/89.8%, and 43.7%/91.9%, respectively. The area under the curve for cancer indicated that using either 2 or 3 tests provided the best discrimination for cancer. CONCLUSIONS: The qFIT provides a higher sensitivity for detecting ACRN and cancer than the GT, and has an acceptable specificity that significantly reduces the need for colonoscopic evaluation in the screened population.

This paper describes a holistic approach to the theory of instantaneous power in three-phase four-wire systems, focusing on the original theory created in 1983 and a modified theory presented in 1994. The two theories are perfectly identical if no zero-sequence voltage is included in a three-phase three-wire system. However, they are different in the instantaneous active and reactive power in each phase if a zero-sequence voltage and current are included in a three-phase four-wire system. Theory and computer simulations in this paper lead to the following conclusions: an active filter without energy storage components can fully compensate for the neutral current even in a three-phase four-wire system including a zero-sequence voltage and current, when a proposed control strategy based on the original theory is applied. However, the active filter cannot compensate for the neutral current fully, when an already-proposed control strategy based on the modified theory is applied.

A phosphor was synthesized using a decomposition method without the use of toxic gas. and ZnCdS:Ag,Cl phosphors were chosen to produce green and red emissions, respectively, under excitation from a blue light emitting diode (LED). A three band white LED was obtained through a combination of nonabsorbed blue emission from a blue LED and green and red emissions from the and ZnCdS:Ag,Cl phosphors. The optical properties of the three band white LED are also discussed. © 2003 The Electrochemical Society. All rights reserved.

A new class of MnCo₂O₄ spinel supported Ru catalyst, Ru/MnCo₂O₄, was exploited to afford the highest yield of FDCA (99.1%) from base-free air-oxidation of HMF in water.

This paper proposed the rotating p-q-r reference frames where one instantaneous active power p, and two instantaneous reactive powers q/sub q/, q/sub r/ were defined in 3-phase 4-wire systems. The three power components are linearly independent, so that compensating for the two instantaneous reactive powers leads to control the two components of the current space vector independently. With the theory, this paper shows that the neutral current of a 3-phase 4-wire system can be eliminated by only compensating for the instantaneous reactive power using no energy storage element. Simulation results verify the theory very well.

Nanomedicine seeks to apply nanoscale materials for the therapy and diagnosis of diseased and damaged tissues. Recent advances in nanotechnology have made a major contribution to the development of multifunctional nanomaterials, which represents a paradigm shift from single purpose to multipurpose materials. Multifunctional nanomaterials have been proposed to enable simultaneous target imaging and on-demand delivery of therapeutic agents only to the specific site. Most advanced systems are also responsive to internal or external stimuli. This approach is particularly important for highly potent drugs (e.g. chemotherapeutics), which should be delivered in a discreet manner and interact with cells/tissues only locally. Both advances in imaging and precisely controlled and localized delivery are critically important in cancer treatment, and the use of such systems - theranostics - holds great promise to minimise side effects and boost therapeutic effectiveness of the treatment. Among others, mesoporous silica nanoparticles (MSNPs) are considered one of the most promising nanomaterials for drug delivery. Due to their unique intrinsic features, including tunable porosity and size, large surface area, structural diversity, easily modifiable chemistry and suitability for functionalization, and biocompatibility, MSNPs have been extensively utilized as multifunctional nanocarrier systems. The combination or hybridization with biomolecules, drugs, and other nanoparticles potentiated the ability of MSNPs towards multifunctionality, and even smart actions stimulated by specified signals, including pH, optical signal, redox reaction, electricity and magnetism. This paper provides a comprehensive review of the state-of-the-art of multifunctional, smart drug delivery systems centered on advanced MSNPs, with special emphasis on cancer related applications.

Lithium-ion batteries with high energy density, long cycle life, and appropriate safety levels are necessary to facilitate the penetration of electrified transportation systems into the automobile market.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population. The Korean Heart Rhythm Society organized a Korean AF Management Guideline Committee and analyzed all available studies regarding the management of AF, including studies on Korean patients. This guideline is based on recent data of the Korean population and the recent guidelines of the European Society of Cardiology, European Association for Cardio-Thoracic Surgery, American Heart Association, and Asia Pacific Heart Rhythm Society. Expert consensus or guidelines for the optimal management of Korean patients with AF were achieved after a systematic review with intensive discussion. This article provides general principles for appropriate risk stratification and selection of anticoagulation therapy in Korean patients with AF. This guideline deals with optimal stroke prevention, screening, rate and rhythm control, risk factor management, and integrated management of AF.

In a paradigm of physician performance we propose that both "cognitive" and "noncognitive" components contribute to the performance of physicians-in-training and in-practice. Our review of the relevant literature indicates that personality, as an important factor of the "noncognitive" component, plays a significant role in academic and professional performances. We describe findings on 14 selected personality instruments in predicting academic and professional performances. We question the contention that personality can be validly and reliably assessed from admission interviews, letters of recommendation, essays, and personal statements. Based on conceptual relevance and currently available empirical evidence, we propose that personality attributes such as conscientiousness and empathy should be considered among the measures of choice for the assessment of pertinent aspects of personality in academic and professional performance. Further exploration is needed to search for additional personality attributes pertinent to medical education and patient care. Implications for career counseling, assessments of professional development and medical education outcomes, and potential use as supplementary information for admission decisions are discussed.

We introduce a high performance hybrid electrochemical energy storage system based on an aqueous electrolyte containing tin sulfate (SnSO₄) and vanadyl sulfate (VOSO₄) with nanoporous activated carbon.

BACKGROUND AND STUDY AIM: Rectal carcinoids are low-grade malignancies that are usually treated by endoscopic resection. However, on pathologic examination, resection margins that are positive for carcinoid cells are frequently found. Patient outcomes were reviewed after endoscopic resection of rectal carcinoids and the clinical significance of possible residual disease, as defined by pathologic and endoscopic examination, was evaluated. PATIENTS AND METHODS: The medical records and endoscopic findings of 347 patients presenting with rectal carcinoids to 14 university hospitals in Korea between January 1999 and June 2007 were retrospectively analyzed. RESULTS: A total of 304 patients were treated with endoscopic resection, and 43 patents were treated with surgery. In the endoscopic resection group, the complete resection rate was 88.2% based on endoscopic appearance (CR-E) and 60.2% based on pathologic evaluation (CR-P). The agreement between CR-E and CR-P was low (κ=0.192). No residual tumors were found in 77 of 85 patients (90.6%) who were CR-E but not CR-P and who had endoscopic biopsy taken at 24-month follow-up. The receiver-operating characteristic curve identified an optimal cut-off value of 10.5 mm, at which the sensitivity and the specificity for metastasis were 100% and 89%, respectively. The risk factors for metastasis by multivariate analysis were tumor size, increased mitotic rate, and lymphovascular invasion. CONCLUSIONS: Endoscopic resection is a safe and effective modality for treating well-differentiated rectal carcinoids smaller than 10 mm in diameter. Discrepancies were observed between CR-E and CR-P. The risk factors for metastasis were tumor size, increased mitotic rate, and lymphovascular invasion.

BACKGROUND: Tegoprazan is a novel potassium-competitive acid blocker that has a fast onset of action and can control gastric pH for a prolonged period, which could offer clinical benefit in acid-related disorders. AIM: To confirm the non-inferiority of tegoprazan to esomeprazole in patients with erosive oesophagitis (EE). METHODS: In this multicentre, randomised, double-blind, parallel-group comparison study, 302 Korean patients with endoscopically confirmed EE (Los Angeles Classification Grades A-D) were randomly allocated to either tegoprazan (50 or 100 mg) or esomeprazole (40 mg) treatment groups for 4 or 8 weeks. The primary endpoint was the cumulative proportion of patients with healed EE confirmed by endoscopy up to 8 weeks from treatment initiation. Symptoms, safety and tolerability were also assessed. RESULTS: The cumulative healing rates at week 8 were 98.9% (91/92), 98.9% (90/91) and 98.9% (87/88) for tegoprazan 50 mg, tegoprazan 100 mg and esomeprazole 40 mg, respectively. Both doses of tegoprazan were non-inferior to esomeprazole 40 mg. The incidence of adverse events was comparable among the groups, and tegoprazan was well-tolerated. CONCLUSION: Once daily administration of tegoprazan 50 or 100 mg showed non-inferior efficacy in healing EE and tolerability to that of esomeprazole 40 mg.

High molecular weight bio furan-based copolyesters have been synthesized by melt polycondensation and solid-state polymerization for packaging applications as bio based alternatives to PET.

Although it is known that the expression and activity of sirtuin 1 (Sirt1) decrease in the aged kidney, the role of interaction between Sirt1 and hypoxia-inducible factor (HIF)-1α is largely unknown. In this study, we investigated whether HIF-1α could be a deacetylation target of Sirt1 and the effect of their interaction on age-associated renal injury. Five-week-old (young) and 24-month-old (old) C57Bl/6J mice were assessed for their age-associated changes. Kidneys from aged mice showed increased infiltration of CD68-positive macrophages, higher expression of extracellular matrix (ECM) proteins, and more apoptosis than young controls. They also showed decreased Sirt1 expression along with increased acetylated HIF-1α. The level of Bcl-2/adenovirus E1B-interacting protein 3, carbonic anhydrase 9, Snail, and transforming growth factor-β1, which are regulated by HIF-1α, was significantly higher in aged mice suggesting that HIF-1α activity was increased. In HK-2 cells, Sirt1 inhibitor sirtinol and siRNA-mediated knockdown of Sirt1 enhanced apoptosis and ECM accumulation. During hypoxia, Sirt1 was down-regulated, which allowed the acetylation and activation of HIF-1α. Resveratrol, a Sirt1 activator, effectively prevented hypoxia-induced production of ECM proteins, mitochondrial damage, reactive oxygen species generation, and apoptosis. The inhibition of HIF-1α activity by Sirt1-induced deacetylation of HIF-1α was confirmed by Sirt1 overexpression under hypoxic conditions and by resveratrol treatment or Sirt1 overexpression in HIF-1α-transfected HK-2 cells. Finally, we confirmed that chronic activation of HIF-1α promoted apoptosis and fibrosis, using tubular cell-specific HIF-1α transgenic mice. Taken together, our data suggest that Sirt1-induced deacetylation of HIF-1α may have protective effects against tubulointerstitial damage in aged kidney.

BACKGROUND AND STUDY AIMS: Although capsule endoscopy has become a central diagnostic tool for small-bowel evaluation, retention of a capsule remains a major concern. This study attempted to investigate the incidence and clinical outcomes of capsule retention, and to determine the factors predictive of spontaneous capsule passage after retention. PATIENTS AND METHODS: Through a nationwide multicenter survey, we retrospectively reviewed the records of 1291 patients who had a capsule endoscopy between February 2002 and July 2006 in Korea. Clinical and procedural characteristics and postprocedural outcomes were analyzed for the cases with capsule retention. RESULTS: Capsule retention occurred in 2.5 % of total cases (32/1291). The major diseases accompanying capsule retention were Crohn's disease, malignant tumors, and tuberculous enterocolitis, in decreasing order. In 11 of the 32 patients (34.4 %), early surgical or endoscopic interventions were instituted for diagnosis or treatment of diseases before retention symptoms developed. The remaining 21 (65.6 %) patients initially received medical treatments. Of these, 10 (31.3 %) ultimately underwent surgical intervention due to the development of symptoms of intestinal obstruction or medical treatment failure. The other 11 (34.4 %) eventually passed the capsule. The presence of a larger lumen diameter (greater than two-thirds of the capsule diameter) at the stricture site was associated with spontaneous passage. CONCLUSIONS: Our large-scale study suggests that retention occurs infrequently during capsule endoscopy. Moreover, a retained capsule might indicate the best intervention for the offending pathology, or it may spontaneously pass in the long run, particularly in patients with less small bowel stricture.

A sustainable method for reclaiming silicon (Si) wafers from an end-of-life photovoltaic module is examined in this paper.