128 research outputs found

    Induction of inducible nitric oxide synthase expression by 18β-glycyrrhetinic acid in macrophages

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    AbstractGlycyrrhizin (GL), a triterpenoid saponin fraction of licorice, is reported to have anti-viral and anti-tumor activities and is metabolized to 18β-glycyrrhetinic acid (GA) in the intestine by intestinal bacteria. However, the mechanism underlying its effects is poorly understood. To further elucidate the mechanism of GA, the aglycone of GL, we investigated the effects of GA on the release of nitric oxide (NO) and at the level of inducible NO synthase (iNOS) gene expression in mouse macrophages. We found that GA elicited a dose-dependent increase in NO production and in the level of iNOS mRNA. Since iNOS transcription has been shown to be under the control of the transcription factor nuclear factor κB (NF-κB), the effects of GA on NF-κB activation were examined. Transient expression assays with NF-κB binding sites linked to the luciferase gene revealed that the increased level of iNOS mRNA, induced by GA, was mediated by the NF-κB transcription factor complex. By using DNA fragments containing the NF-κB binding sequence, GA was shown to activate the protein/DNA binding of NF-κB to its cognate site, as measured by electrophoretic mobility shift assay. These results demonstrate that GA stimulates NO production and is able to up-regulate iNOS expression through NF-κB transactivation in macrophages

    Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System

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    To increase the heat capacity in lightweight construction materials, a phase change material (PCM) can be introduced to building elements. A thermally activated building system (TABS) with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results

    A cost-effectiveness study of universal screening for hepatitis C virus infection in South Korea: A societal perspective

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    Background/Aims: This study aimed to evaluate the cost-effectiveness of hepatitis C virus (HCV) screening compared to no screening in the Korean population from societal and healthcare system perspectives. Methods: A published decision-tree plus Markov model was used to compare the expected costs and quality-adjusted life years (QALY) between one-time universal HCV screening and no screening in the population aged 40-65 years using the National Health Examination (NHE) program. Input parameters were obtained from analyses of the National Health Insurance claims data, Korean HCV cohort data, or from the literature review. The population aged 40-65 years was simulated in a model spanning a lifetime from both the healthcare system and societal perspectives, which included the cost of productivity loss due to HCV-related deaths. The incremental cost-effectiveness ratio (ICER) between universal screening and no screening was estimated. Results: The HCV screening strategy had an ICER of 2,666/QALYand2,666/QALY and 431/QALY from the healthcare system and societal perspectives, respectively. Both ICERs were far less than the willingness-to-pay threshold of $25,000/QALY, showing that universal screening was highly cost-effective compared to no screening. In various sensitivity analyses, the most influential parameters on cost-effectiveness were the antibodies to HCV (anti-HCV) prevalence, screening costs, and treatment acceptance; however, all ICERs were consistently less than the threshold. If the anti-HCV prevalence was over 0.18%, screening could be cost-effective. Conclusions: One-time universal HCV screening in the Korean population aged 40-65 years using NHE program would be highly cost-effective from both healthcare system and societal perspectives.Y

    A Case of Papillary Thyroid Cancer Recurring as an Esophageal Submucosal Tumor

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    A 75-year-old woman who underwent a total thyroidectomy for papillary thyroid cancer 7 years previously presented with a palpable neck mass. Computed tomography (CT) showed two metastatic masses on the thyroid bed and another mass that looked benign originating from the esophageal wall. Endoscopic ultrasonography (EUS) showed a hypoechoic mass in the esophageal wall that looked similar to a gastrointestinal stromal tumor. The mass on the esophagus had intense fluorodeoxyglucose (FDG) uptake in positron emission tomography-computed tomography (PET-CT), which suggested the possibility of malignancy. Subsequently, after surgery, the mass in the esophagus was confirmed as a metastasis from the thyroid papillary carcinoma. Here we report this unusual case of papillary thyroid cancer that recurred as an esophageal submucosal tumor

    Hepatocellular carcinoma with Budd-Chiari syndrome due to membranous obstruction of the inferior vena cava with long-term follow-up: a case report

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    Membranous obstruction of the inferior vena cava (MOVC) is a rare subset of Budd-Chiari syndrome (BCS) with a subacute onset that is often complicated by cirrhosis and hepatocellular carcinoma (HCC). Here we report a case of recurrent HCC in a patient with cirrhosis and BCS that was treated with several episodes of transarterial chemoembolization followed by surgical tumorectomy, whereas the MOVC was successfully treated with balloon angioplasty followed by endovascular stenting. The patient was followed up for 9.9 years without anticoagulation and experienced no stent thrombosis. After the tumorectomy, the patient was HCC-free for 4.4 years of follow-up

    Circulating tumor cells detected by lab-on-adisc: Role in early diagnosis of gastric cancer

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    [Background] The use of circulating tumor cells (CTCs) as an early diagnostic biomarker and prognostic indicator after surgery or chemotherapy has been suggested for various cancers. This study aimed to evaluate CTCs in patients who underwent gastrectomy for gastric cancer and to explore their clinical usefulness in the early diagnosis of gastric cancer. [Methods] A total of 116 patients with gastric cancer who underwent gastrectomy and 31 healthy volunteers were prospectively included between 2014 and 2015. Peripheral blood samples were collected before gastrectomy, and CTCs were examined using a centrifugal microfluidic system with a new fluid-assisted separation technique. [Results] After creating a receiver operating characteristic curve to identify the discriminative CTC value needed differentiate patients with gastric cancer from healthy volunteers, sensitivity and specificity were nearly optimized at a CTC threshold of 2 per 7.5 mL of blood. Of the 102 persons with a CTC level >= 2 per 7.5 mL of blood, 99 (97.1%) had gastric cancer, and of the 45 persons with a CTC level <2 per 7.5 mL of blood, 28 (62.2%) were healthy controls. Accordingly, the sensitivity and specificity for the differentiation of patients with gastric cancer from healthy controls were 85.3% and 90.3%, respectively. However, the presence of CTCs was not associated with any clinicopathologic features such as staging, histologic type, or mucin phenotype. [Conclusion] Although we could not prove the clinical feasibility of CTCs for gastric cancer staging, our results suggest a potential role of CTCs as an early diagnostic biomarker of gastric cancer

    The coffee diterpene kahweol induces heme oxygenase-1 via the PI3K and p38/Nrf2 pathway to protect human dopaminergic neurons from 6-hydroxydopamine-derived oxidative stress

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    AbstractIn this study, we investigated the mechanisms of kahweol protection of neuronal cells from cell death induced by the Parkinson’s disease-related neurotoxin 6-hydroxydopamine (6-OHDA). Pretreatment of SH-SY5Y cells with kahweol significantly reduced 6-OHDA-induced generation of ROS, caspase-3 activation, and subsequent cell death. Kahweol also up-regulated heme oxygenase-1 (HO-1) expression, which conferred neuroprotection against 6-OHDA-induced oxidative injury. Moreover, kahweol induced PI3K and p38 activation, which are involved in the induction of Nrf2, HO-1 expression, and neuroprotection. These results suggest that regulation of the anti-oxidant enzyme HO-1 via the PI3K and p38/Nrf2 signaling pathways controls the intracellular levels of ROS
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