Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory disorder with an unknown etiology. IBD is composed of two different disease entities: Crohn's disease (CD) and ulcerative colitis ...(UC). IBD has been thought to be idiopathic but has two main attributable causes that include genetic and environmental factors. The gastrointestinal tract in which this disease occurs is central to the immune system, and the innate and the adaptive immune systems are balanced in complex interactions with intestinal microbes under homeostatic conditions. However, in IBD, this homeostasis is disrupted and uncontrolled intestinal inflammation is perpetuated. Recently, the pathogenesis of IBD has become better understood owing to advances in genetic and immunologic technology. Moreover, new therapeutic strategies are now being implemented that accurately target the pathogenesis of IBD. Beyond conventional immunesuppressive therapy, the development of biological agents that target specific disease mechanisms has resulted in more frequent and deeper remission in IBD patients, with mucosal healing as a treatment goal of therapy. Future novel biologics should overcome the limitations of current therapies and ensure that individual patients can be treated with optimal drugs that are safe and precisely target IBD.
The outbreak of coronavirus disease 2019 (COVID-19), which began in December 2019, is still ongoing in Korea, with >9,000 confirmed cases as of March 25, 2020. COVID-19 is a severe acute respiratory ...syndrome Coronavirus 2 (SARS-CoV-2) infection, and real-time reverse transcription-PCR is currently the most reliable diagnostic method for COVID-19 around the world. Korean Society for Laboratory Medicine and the Korea Centers for Disease Prevention and Control propose guidelines for diagnosing COVID-19 in clinical laboratories in Korea. These guidelines are based on other related domestic and international guidelines, as well as expert opinions and include the selection of test subjects, selection of specimens, diagnostic methods, interpretation of test results, and biosafety.
•Multi-objective optimization of a HPLD air-conditioning system is conducted.•Effects of operating parameters on two objective functions are investigated.•Pareto front is obtained using a ...multi-objective genetic algorithm.•Final optimum solution in many situations is derived by decision-making scenario.•Each energy and capacity-matching performance is improved by up to 24 % and 55 %.
In heat-pump-driven liquid-desiccant (HPLD) air-conditioning systems, releasing condensing heat from heat pump to regenerator solution and exhaust air (i.e., capacity matching) is important for maintaining dehumidification performance, operational feasibility, and system stability. Therefore, this study optimizes capacity matching, especially focusing on releasing extra condensing heat, which has simply been assumed to be well-treated in previous studies, in conjunction with energy performance. With four design variables under various outdoor air conditions, a multi-objective optimization is conducted to simultaneously maximize system coefficient of performance (COP) and minimize a newly defined capacity-matching index of extra condenser. Pareto front, a set of optimum points, is obtained using a multi-objective genetic algorithm. Final optimum solutions are then determined and discussed based on a decision-making scenario. In optimization results, the regenerator air and solution flow rates should be respectively greater and lower than those of the absorber. The optimum temperature of absorber inlet solution is generally distributed at approximately 18 °C, while that of regenerator inlet solution is significantly influenced by the decision-making scenario. Finally, the system COP was maximally increased by 24 %, and the capacity-matching index of extra condenser was maximally decreased by 55 %, compared with each initial value.
In this study, the ablation characteristics of carbon/phenolic composites were evaluated using X-ray microtomography. The ablation tests of carbon/phenolic composites were performed using a 0.4 MW ...arc-heated wind tunnel, and the composite samples were scanned using micro-computed tomography (Micro-CT) to analyze the ablation characteristics according to the duration of the ablation test. Through calibration of the scanned raw images, ~2,000 cross-sectional images were generated with micrometer level intervals. Using these obtained cross-sectional images, the porosity and density distributions in the longitudinal direction of the samples were calculated. The mass was then calculated using the analyzed porosity and density, and gave an error of 0.1–3.4% compared to the mass measured using an electronic balance. Our observations indicate that the physical properties of carbon/phenolic composite samples can be calculated using X-ray microtomography, and we expect that our results will be useful in analyzing the behavior of ablative composites.
Microbial dysbiosis has long been postulated to be associated with the pathogenesis of inflammatory bowel disease (IBD). Although evidence supporting the anti-colitic effects of melatonin have been ...accumulating, it is not clear how melatonin affects the microbiota. Herein, we investigated the effects of melatonin on the microbiome in colitis and identified involvement of Toll-like receptor (TLR) 4 signalling in the effects. Melatonin improved dextran sulfate sodium (DSS)-induced colitis and reverted microbial dysbiosis in wild-type (WT) mice but not in TLR4 knockout (KO) mice. Induction of goblet cells was observed with melatonin administration, which was accompanied by suppression of Il1b and Il17a and induction of melatonin receptor and Reg3β, an antimicrobial peptide (AMP) against Gram-negative bacteria. In vitro, melatonin treatment of HT-29 intestinal epithelial cells promotes mucin and wound healing and inhibits growth of Escherichia coli. Herein, we showed that melatonin significantly increases goblet cells, Reg3β, and the ratio of Firmicutes to Bacteriodetes by suppressing Gram-negative bacteria through TLR4 signalling. Our study suggests that sensing of bacteria through TLR4 and regulation of bacteria through altered goblet cells and AMPs is involved in the anti-colitic effects of melatonin. Melatonin may have use in therapeutics for IBD.
Inflammatory bowel disease (IBD) is a chronic relapsing intestinal inflammatory disorder with unidentified causes. Currently, studies indicate that IBD results from a complex interplay between ...various genetic and environmental factors that produce intestinal inflammation. However, these factors may differ for Asians and Caucasians. Thus, differences in epidemiology, genetic variants, and clinical phenotypes of IBD have been observed between the two populations. Understanding the discrepancies between data from populations with different genetic backgrounds and environmental factors may reveal fundamental aspects of IBD pathogenesis. Accordingly, this review will summarize the current knowledge of IBD genetics studied in Asian countries and compare it with that from Western countries, with special focus on innate bacterial sensing, autophagy, and the interleukin‐23 receptor‐T helper cell 17 pathway. The epigenetic nature of IBD pathogenesis as well as the pharmacogenetics related to the use of immunomodulators will also be briefly covered.
The incidence and prevalence of inflammatory bowel diseases (IBDs) are rapidly increasing worldwide. IBDs are considered an emerging problem not only in Western countries but also in developing ...counties. The relapses and complications of active IBD mandate various medications. Nevertheless, hospitalization, emergency room visits, or surgery may be required, resulting in a socioeconomic burden. Great advances have been made in the development of new therapeutic options for IBD to achieve induction and maintenance remission. Nevertheless, conventional therapy is still the mainstay in the treatment of IBD. This review article provides an update on recent advances in conventional therapies, including 5-aminosalicylates, corticosteroids, immunomodulators, and anti-tumor necrosis factor-α agents to treat IBD.
PURPOSE OF REVIEWThis review discusses recent scientific developments in the diagnosis, treatment, and prognosis of intestinal Behçetʼs disease.
RECENT FINDINGSGastrointestinal involvement is a major ...cause of morbidity and mortality in Behçetʼs disease. Patient clinical data are scarce because of the rarity of the disease; however, novel diagnostic criteria and disease activity indices have been developed recently to aid treatment of Behçetʼs disease patients. Current therapies include 5-aminosalicylic acids, corticosteroids, immunomodulators, or antitumor necrosis factor alpha agents. Antitumor necrosis factor alpha agents can achieve clinical responses and remission in patients that were previously nonresponsive to corticosteroids or immunomodulators. Clinical variables, including young age and higher disease activity at the time of diagnosis, volcano-type ulcers, absence of mucosal healing, higher C-reactive protein levels, prior history of surgery, and lack of initial response to medical therapy, can be regarded as poor prognostic factors.
SUMMARYPreviously, the diagnosis and management of intestinal Behçetʼs disease depended upon the expertise of individual clinicians; however, more standardized medical assessments and improved treatment regimens for Behçetʼs disease patients are evolving.
Metformin has been known to suppress cancer stem cells (CSCs) in some cancers. However, the differential effects of metformin on CSCs and their mechanisms have not been reported. Herein, metformin ...induced pAMPK activation and pS6 suppression in metformin-sensitive (HT29) cells, but not in metformin-resistant (SW620) cells. The oxygen consumption rate was higher in HT29 cells than in SW620 cells and showed a prominent decrease after metformin treatment in HT29 cells. In glutamine-depleted medium, but not in low-glucose medium, SW620 cells became sensitive to the CSC-suppressing effect of metformin. A combination of metformin and glutaminase C inhibitor (compound 968) suppressed CSCs in SW620 cells and enhanced that effect in HT29 cells. SW620 cells showed higher expression of glutaminase 1 and glutamine transporter (ASCT2) than HT29 cells, especially ASCT2 in CSCs. Knockdown of glutaminase 1, ASCT2, and c-Myc induced significant CSC-suppression and enhanced CSC-suppressing effect of metformin and compound 968. In xenografts and human cancer organoids, combined treatment with metformin and compound 968 showed the same results as those shown in vitro. In conclusion, the effect of metformin on CSCs varies depending on the AMPK-mTOR and glutamine metabolism. The inhibition of glutamine pathway could enhance the CSC-suppressing effect of metformin, overcoming metformin resistance.
PDF
