Cascade Sequence of Photooxygenation-Epoxidation for the Flow Synthesis of Epoxy Alcohols.

A photooxygenation-epoxidation cascade sequence converting alkenes to epoxy alcohols was developed and evaluated in batch and continuous-flow systems. In the batch system, the undesired interactions between the photooxygenation and epoxidation catalysts resulted in suboptimal yields, whereas the fine control of reaction parameters in the flow system allowed the allyl hydroperoxides produced through photooxygenation of alkenes to be rapidly converted to epoxy alcohols in yields of up to 93%. The developed procedure allows one to avoid an important synthetic bottleneck, works well where traditional batch synthesis fails, and can be scaled up to meet the needs of industrial production, thus presenting a valuable addition to the toolbox of practicing organic chemists.

Crystal structures of human NSDHL and development of its novel inhibitor with the potential to suppress EGFR activity.

NAD(P)-dependent steroid dehydrogenase-like (NSDHL), an essential enzyme in human cholesterol synthesis and a regulator of epidermal growth factor receptor (EGFR) trafficking pathways, has attracted interest as a therapeutic target due to its crucial relevance to cholesterol-related diseases and carcinomas. However, the development of pharmacological agents for targeting NSDHL has been hindered by the absence of the atomic details of NSDHL. In this study, we reported two X-ray crystal structures of human NSDHL, which revealed a detailed description of the coenzyme-binding site and the unique conformational change upon the binding of a coenzyme. A structure-based virtual screening and biochemical evaluation were performed and identified a novel inhibitor for NSDHL harboring suppressive activity towards EGFR. In EGFR-driven human cancer cells, treatment with the potent NSDHL inhibitor enhanced the antitumor effect of an EGFR kinase inhibitor. Overall, these findings could serve as good platforms for the development of therapeutic agents against NSDHL-related diseases.

Discrete terminal ileal ulcers in patients diagnosed with ulcerative colitis: clinical significance and natural course.

BACKGROUND: Terminal ileal (TI) ulcers are occasionally detected in asymptomatic individuals and mostly resolve without any treatment. In patients with ulcerative colitis (UC), TI ulcers are infrequently observed without evidence of backwash ileitis. However, the clinical significance and natural course of the lesions are unclear. The aim of our study was to evaluate the frequency and clinical implications of TI ulcers in patients with UC. METHODS: We retrospectively reviewed 397 patients with UC via successful TI intubation during colonoscopy. We compared the clinical characteristics of patients manifesting TI ulcers with those who did not. The natural course of TI lesions was also investigated during the follow-up periods. RESULTS: Forty-one patients (10.3%) showed TI ulcers without evidence of inflammation in the right colon. The patients with and without TI ulcers were not different in terms of baseline characteristics, disease activity and extent at the time of the UC diagnosis, proximal extension, Mayo endoscopic score at the last endoscopic examination, medication history, UC-related hospitalization, and relapse during follow-up periods. Of the 30 patients who underwent follow-up colonoscopy in patients with TI ulcers, 23 (76.7%) showed resolution of TI ulcer. In addition, patients with remaining TI ulcers did not differ in disease activity and biopsy results compared with those with resolving TI ulcers. CONCLUSIONS: Discrete TI ulcers are more common in patients with UC, compared with the healthy cohort. No significant clinical impact on disease extension and severity is found.

Structural Basis of Inhibition of DCLK1 by Ruxolitinib.

Given the functional attributes of Doublecortin-like kinase 1 (DCLK1) in tumor growth, invasion, metastasis, cell motility, and tumor stemness, it is emerging as a therapeutic target in gastrointestinal cancers. Although a series of specific or nonspecific ATP-competitive inhibitors were identified against DCLK1, different types of scaffolds that can be utilized for the development of highly selective inhibitors or structural understanding of binding specificities of the compounds remain limited. Here, we present our work to repurpose a Janus kinase 1 inhibitor, ruxolitinib as a DCLK1 inhibitor, showing micromolar binding affinity and inhibitory activity. Furthermore, to gain an insight into its interaction mode with DCLK1, a crystal structure of the ruxolitinib-complexed DCLK1 has been determined and analyzed. Ruxolitinib as a nonspecific DCLK1 inhibitor characterized in this work is anticipated to provide a starting point for the structure-guided discovery of selective DCLK1 inhibitors.

Factors of Depressive Symptoms Among Elementary, Middle, and High School Students.

Little attention has been paid to the individual, family, friends, and school profiles of depressed children during the transition from childhood to adolescence. This study aimed to describe the evolution of factors associated with depressive symptoms among elementary, middle, and high school students. This was a secondary analytic study using three datasets of a cohort of Korean children or adolescents. Children or adolescents with depressed symptoms reported lower self-esteem, peer attachment, academic performance, and adaptability in school. Other risk factors for depressive symptoms that included gender, obesity, family conflict, and with whom they discussed personal issues showed different patterns from the elementary school years to high school years. A sex difference (female>male) of depressive symptoms was evident only among high school students. Influences including individuals, family, friends, and school factors for adolescents varied depending upon school years. Understanding the correlates/risk factors could guide the screening and management of depressive symptoms.

In vitro neuroprotective activity of sesquiterpenoids from the flower buds of Tussilago farfara.

We have isolated four sesquiterpenoids from Tussilago farfara, a traditional herbal medicine in Korea and China, and investigated the protective effects on LPS-induced neuronal cell death. Four sesquiterpenoids inhibited the production of nitric oxide, prostaglandin E2 and tumor necrosis factor-α in LPS-treated BV-2 cells through the inhibition of NF-κB pathway. These sesquiterpenoids also inhibited reactive oxygen species (ROS) generation in LPS-treated BV-2 cells. Furthermore, they inhibited LPS-induced neuronal cell death in co-culture system through the inhibition of NF-κB pathway and scavenging of ROS. These results indicated that sesquiterpenoids from Tussilago farfara may have beneficial therapeutic potential for the treatment of neurodegenerative diseases through inhibition of microglial activation.

Association between proton pump inhibitors use and risk of asthma in Korea: A prevalent new-user cohort study.

There have been conflicting mechanisms that proton pump inhibitors (PPIs) may promote or prevent asthma development. However, the evidence on the association of PPI use with the risk of asthma and its exposure-response relationship has been limited. We aim to identify the association between the use of PPIs and the incidence of asthma, compared with use of histamine 2 receptor antagonists (H2RAs). A nationwide, prevalent new-user cohort study was conducted using Korea's National Sample Cohort database. Patients were defined as PPI or H2RA users between 2003 and 2019. PPI users matched to H2RA users based on time-conditional propensity score. Cox proportional hazards model was used to estimate adjusted hazard ratios with 95% confidence intervals of incident asthma associated with PPI use by duration of use, cumulative dose, and average dose per duration. Among the 250,041 pairs, PPI users (51.3% male; mean [SD] age, 42.6 [16.5]; mean follow-up, 6.7 years) showed a higher incidence rate of asthma (7.94 events per 1000 person-year) compared to H2RA users (3.70 events per 1000 person-year) with adjusted hazard ratio of 2.15 (95% confidence interval = 2.08-2.21). The risk of asthma was significantly increased across all observed groups of duration of use, cumulative dose, and average dose per duration. This study suggested that PPI use is associated with an increased risk of developing asthma compared to H2RA use.

Efficacy and Safety of Once-Weekly Semaglutide Versus Once-Daily Sitagliptin as Metformin Add-on in a Korean Population with Type 2 Diabetes.

INTRODUCTION: Glucagon-like peptide-1 receptor agonists are well-established type 2 diabetes (T2D) treatments. As variations among populations and culture might influence treatment effects, this post hoc analysis evaluates the efficacy and safety of once-weekly (OW) semaglutide in a Korean population. METHODS: Korean adults with T2D inadequately controlled on metformin included in a 30-week, phase 3a, international, multicentre trial (NCT03061214) compared OW subcutaneous semaglutide (0.5 mg and 1.0 mg) with once-daily sitagliptin (100 mg). Key endpoints included change in glycated haemoglobin (HbA1c) and body weight; additional endpoints assessed proportions of participants reaching targets of HbA1c < 7.0% and ≤ 6.5%, ≥ 5% weight loss, and a composite endpoint of HbA1c < 7.0% without severe/blood glucose-confirmed symptomatic hypoglycaemia and no weight gain. RESULTS: Korean participants (n = 110) showed a greater reduction in HbA1c and body weight with semaglutide 0.5 mg (-1.6%, -2.7 kg) and 1.0 mg (-1.8%, -4.8 kg) versus sitagliptin (-0.9%, 0.5 kg). HbA1c targets of < 7.0% and ≤ 6.5% were achieved by more participants treated with semaglutide 0.5 mg (80.0% and 60.0%, respectively) and 1.0 mg (87.5% and 67.5%, respectively) versus sitagliptin (54.3% and 25.7%, respectively); ≥ 5% weight loss was observed in 42.9% and 65.0% of participants treated with semaglutide 0.5 mg and 1.0 mg versus 0.0% with sitagliptin. The composite endpoint was achieved by 71.4%, 77.5%, and 31.4% of the population in the semaglutide 0.5 mg, 1.0 mg, and sitagliptin group, respectively. No new safety concerns were observed. CONCLUSION: This analysis confirms efficacy and safety of OW semaglutide (0.5 and 1.0 mg) in a Korean population with T2D. CLINICAL TRIAL REGISTRATION NUMBER: NCT03061214.

Safety and Clinical Outcomes of Insulin Degludec in Korean Patients with Diabetes in Real-World Practices: A Prospective, Observational Study.

INTRODUCTION: To investigate the safety and effectiveness of insulin degludec (IDeg) in a real-world population of Korean patients with diabetes requiring insulin therapy. METHODS: This was a multicenter, prospective, single-arm, open-label, non-interventional study. Patients aged ≥ 12 months and treated with previous glucose-lowering medications were eligible to switch to IDeg. The primary endpoint was the incidence of adverse events (AEs), and the secondary endpoints were changes in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), postprandial glucose (PPG), and target HbA1c < 7.0%. RESULTS: In total, 3225 and 2450 patients were included in the safety analysis set (SAS) and effectiveness analysis set (EAS), respectively. The mean baseline HbA1c and duration of diabetes were 9.4% and 13.0 years, respectively. Adverse events were reported in 740 patients (22.9%); the majority were mild and resolved. Significant improvements were observed in HbA1c, FPG, and PPG at week 26 (all p < 0.0001). The target of HbA1c < 7% was achieved in 22.2% of patients at week 26. CONCLUSION: In real-world clinical practice, 26 weeks of IDeg treatment resulted in significant reductions in glycemic parameters with a low incidence of AEs in Korean patients with diabetes. No new safety signals were observed. CLINICAL TRIALS REGISTRY AND REGISTRATION NUMBER: This trial is registered under ClinicalTrials.gov (NCT02779413) and the universal trial number is [U1111-1176-2287].

Exploration of Variables Predicting Sense of School Belonging Using the Machine Learning Method-Group Mnet.

The purpose of this study was to explore variables related to school belonging from a holistic perspective, including a large number of variables in one model, different to the traditional analytical method. Using 2015 data from the Program for International Student Assessment (PISA), we sought to identify variables related to school belonging by searching for hundreds of predictors in one model using the group Mnet machine learning technique. The study repeated 100 rounds of model building after random data splitting. After exploring 504 variables (384 student and 99 parent), 32 variables were finally selected after selection counts. Variables predicting a sense of school belonging were categorized as individual/parent variables (e.g. motivation to achieve, tendency to cooperative learning, parental support) and school-related variables (e.g. school satisfaction, peer/teacher relationship, learning/physical activities). The significance and implications of the study as well as future research topics were discussed.

Two New Species and Three New Records of Ascomycetes in Korea.

During a survey of plant-inhabiting fungi and water niches from Korea, noteworthy fungi were collected; among them, two new species, Paracamarosporium noviaquum sp. nov. and Phyllosticta gwangjuensis sp. nov., are described based on morphology and multi-gene phylogenies. Paracamarosporium noviaquum was characterized by its production of 1-celled and 2-celled conidia, forming conidiomata on only potato dextrose agar medium. Phyllosticta gwangjuensis was characterized by conidia hyaline, ovoid to ellipsoid shape, rounded at both ends, containing numerous guttulae or with a single large central guttule. Additional species were identified as Cosmospora lavitskiae, Monochaetia cameliae, and Roussoella doimaesalongensis, which are reported as new record species from Korea. Detailed descriptions and illustrations of these taxa are provided herein.

A germacranolide sesquiterpene lactone suppressed inducible nitric oxide synthase by downregulating NF-κB activity.

A germacranolide sesquiterpene lactone, 2α,5-epoxy-5,10-dihydroxy-6α-angeloyloxy-9ß-(3-methylbutyloxy)-germacran-8α,12-olide (EDAG), isolated from Carpesium triste var. manshuricum, showed inhibitory activity in the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS) mRNA and protein in LPS-activated macrophage cells. Molecular analysis reveals that these suppressive effects are correlated with the inhibition of NF-κB activation by EDAG. Immunoblotting showed that EDAG suppressed the LPS-induced degradation of I-κBα and decreased nuclear translocation of p65. Furthermore, EDAG showed reduced phosphorylation of ERK1/2 and p38 MAPK, whereas activation of JNK was not changed. These data suggest, at least in part, that EDAG utilizes the signal cascades of ERK1/2, p38 MAPK, and NF-κB for the suppression of iNOS gene expression.

Six Newly Recorded Fungal Taxa from Freshwater Niche in Korea.

Six interesting fungal strains were isolated during a survey of fungal diversity associated with freshwater; these strains were designated as CNUFC YJW2-22, CNUFC MSW11-6-2, CNUFC HRS5-3, CNUFC MSW242-6, CNUFC DMW2-2, and CNUFC CPWS-1. Based on a polyphasic approach including phylogenetic analyses of internal transcribed space (ITS), large subunit (LSU), beta-tubulin (BenA), and calmodulin (CaM) gene sequences, morphological analyses, the six strains were found to be identical to Acremonium guillematii, Cadophora novi-eboraci, Lectera nordwiniana, Mycoarthris corallina, Talaromyces siamensis, and Tetracladium globosum, respectively. To our knowledge, these are the first records of the rare Lectera, Mycoarthris, and Tetracladium genera in Korea, and the first reports of A. guillematii, C. novi-eboraci, L. nordwiniana, M. corallina, T. siamensis, and Te. globosum in a freshwater environment.

Discovery and Extrolite Production of Three New Species of Talaromyces Belonging to Sections Helici and Purpurei from Freshwater in Korea.

Three novel fungal species, Talaromyces gwangjuensis, T. koreana, and T. teleomorpha were found in Korea during an investigation of fungi in freshwater. The new species are described here using morphological characters, a multi-gene phylogenetic analysis of the ITS, BenA, CaM, RPB2 regions, and extrolite data. Talaromyces gwangjuensis is characterized by restricted growth on CYA, YES, monoverticillate and biverticillate conidiophores, and globose smooth-walled conidia. Talaromyces koreana is characterized by fast growth on MEA, biverticillate conidiophores, or sometimes with additional branches and the production of acid on CREA. Talaromyces teleomorpha is characterized by producing creamish-white or yellow ascomata on OA and MEA, restricted growth on CREA, and no asexual morph observed in the culture. A phylogenetic analysis of the ITS, BenA, CaM, and RPB2 sequences showed that the three new taxa form distinct monophyletic clades. Detailed descriptions, illustrations, and phylogenetic trees are provided.

Carabrol suppresses LPS-induced nitric oxide synthase expression by inactivation of p38 and JNK via inhibition of I-kappaBalpha degradation in RAW 264.7 cells.

Carabrol, isolated from Carpesium macrocephalum, showed anti-inflammatory potential in LPS-induced RAW 264.7 murine macrophages. In present study, carabrol demonstrated the inhibitory activity on pro-inflammatory cytokines such as IL-1beta, IL-6 and TNF-alpha. In addition, mRNA and protein levels of iNOS and COX-2 were reduced by carabrol. Molecular analysis revealed that these suppressive effects were correlated with the inactivation of p38 and JNK via inhibition of NF-kappaB activation. Immunoblotting showed that carabrol suppressed LPS-induced degradation of I-kappaBalpha and decreased nuclear translocation of p65. Taken together, these results suggest that carabrol can be a modulator of pro-inflammatory signal transduction pathway in RAW 264.7 cells.

Suppression of inducible nitric oxide synthase expression by furfuran lignans from flower buds of Magnolia fargesii in BV-2 microglial cells.

Activated microglia produces diverse neurotoxic factors such as nitric oxide (NO) and tumor necrosis factor-alpha that serve as apoptotic inducers resulting in various neurodegenerative diseases. The inhibition of microglia-derived NO production by inducible nitric oxide synthase (iNOS) has been reported to be beneficial in retarding neurodegenerative disorders. Three active lignans have been isolated from the flower buds of Magnolia fargesii by the bioassay-guided fractionation using lipopolysaccharide (LPS)-activated BV-2 microglial cell culture system. The structures of them were identified as kobusin (1), aschantin (2) and fargesin (3) by the analyses of spectroscopic data. They inhibited the production of NO by activated microglia. Their IC(50) values were 21.8 +/- 3.7, 14.8 +/- 2.5 and 10.4 +/- 2.8 microg/mL, respectively. They suppressed LPS-induced NF-kappaB activation and the expression of iNOS protein and mRNA. Furthermore, they showed scavenging activity of neurotoxic peroxynitrite that can be produced by NO and superoxide anion. These results imply that lignans from Magnolia fargesii might be beneficial for the treatment of neuro-inflammatory diseases through the inhibition of iNOS expression and peroxynitrite scavenging potential.

In vitro anti-inflammatory activity of lignans isolated from Magnolia fargesii.

The overproduction of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) causes neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Four lignans, (+)-eudesmin (1), (+)-magnolin (2), (+)-yangambin (3) and a new structure named as epimagnolin B (4) were isolated from Magnolia fargesii (Magnoliaceae) as the inhibitors of NO production in LPS-activated microglia. The most potent compound 4 inhibited the production of NO and PGE(2) and the expression of respective enzyme iNOS and COX-2 through the suppression of I-kappaB-alpha degradation and nuclear translocation of p65 subunit of NF-kappaB.

Structural and enzymatic characterization of DR1281: A calcineurin-like phosphoesterase from Deinococcus radiodurans.

We have determined the crystal structure of DR1281 from Deinococcus radiodurans. DR1281 is a protein of unknown function with over 170 homologs found in prokaryotes and eukaryotes. To elucidate the molecular function of DR1281, its crystal structure at 2.3 A resolution was determined and a series of biochemical screens for catalytic activity was performed. The crystal structure shows that DR1281 has two domains, a small alpha domain and a putative catalytic domain formed by a four-layered structure of two beta-sheets flanked by five alpha-helices on both sides. The small alpha domain interacts with other molecules in the asymmetric unit and contributes to the formation of oligomers. The structural comparison of the putative catalytic domain with known structures suggested its biochemical function to be a phosphatase, phosphodiesterase, nuclease, or nucleotidase. Structural analyses with its homologues also indicated that there is a dinuclear center at the interface of two domains formed by Asp8, Glu37, Asn38, Asn65, His148, His173, and His175. An absolute requirement of metal ions for activity has been proved by enzymatic assay with various divalent metal ions. A panel of general enzymatic assays of DR1281 revealed metal-dependent catalytic activity toward model substrates for phosphatases (p-nitrophenyl phosphate) and phosphodiesterases (bis-p-nitrophenyl phosphate). Subsequent secondary enzymatic screens with natural substrates demonstrated significant phosphatase activity toward phosphoenolpyruvate and phosphodiesterase activity toward 2',3'-cAMP. Thus, our structural and enzymatic studies have identified the biochemical function of DR1281 as a novel phosphatase/phosphodiesterase and disclosed key conserved residues involved in metal binding and catalytic activity.

Selenium suppresses the activation of transcription factor NF-kappa B and IRF3 induced by TLR3 or TLR4 agonists.

Toll-like receptors (TLRs) play an important role in recognition of microbial components and induce innate immune responses by recognizing invading microbial pathogens leading to the activation of the adaptive immune responses. The microbial components trigger the activation of two downstream signaling pathways of TLRs; MyD88- and TRIF-dependent pathways leading to the expression of pro-inflammatory cytokines and type I interferons (IFNs). The MyD88- and TRIF-dependent pathways lead to the activation of NF-kappa B and IRF3 through the activation of IKK-beta and TBK1, respectively. Selenium is an essential trace element nutrient possessing anticarcinogenic properties. Here, we attempted to identify the molecular targets of selenium in TLR signaling pathways. Selenium inhibited NF-kappaB activation induced by poly[I:C] (TLR3 agonist), LPS (TLR4 agonist) or overexpression of MyD88 or IKK-beta which is the key kinase of MyD88-dependent signaling pathway. Selenium inhibited IRF3 activation induced by poly[I:C], LPS or the overexpression of TRIF or TBK1. Selenium also suppressed the expression of COX-2 and iNOS and the endogenous IFN beta mRNA induced by poly[I:C] or LPS. Therefore, our results suggest that selenium can modulate both MyD88- and TRIF-dependent signaling pathways of TLRs leading to decreased inflammatory gene expression.

In vitro anti-inflammatory activity of 3-O-methyl-flavones isolated from Siegesbeckia glabrescens.

Four flavones, 3,4'-O-dimethylquercetin (1), 3,7-O-dimethylquercetin (2), 3-O-methylquercetin (3) and 3,7,4'-O-trimethylquercetin (4) were isolated as the inhibitors of nitric oxide production in activated microglia (IC(50) values: 11.1, 4.2, 3.8, and 25.1 microM, respectively). They suppressed the expression of protein and mRNA of inducible nitric oxide synthase. Furthermore, compounds 2 and 3 showed scavenging activity of peroxynitrite with SC(50) values of 1.75 and 0.77 microM, respectively.