• Biomolecules & Therapeutics
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• 제4권2호
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• pp.162-166
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• 1996

This study was done to investigate whether cholic acid derivatives have anti-stress activity and what is a cause of this anti-stress effect. Seven cholic acid derivatives (cholic acid, taurocholic acid, ursodeoxycholic acid, tauroursodeoxychoic acid, chenodeoxy cholic acid, dehydrocholic acid, hyodeoxycholic acid) were used, silymarin and valproic acid were used as positive controls. Stress was induced by restraint immobilization technique plus water immersion (24hrs) and adrenal weight, spleen weight, adrenal ascorbic acid, serum cholesterol, lactate dehydrogenase (LDH), alkaline phosphatase (ALP), adrenal cholesterol, glucose and corticosterone levels were measured as stress indicators. Most cholic acid derivatives markedly decreased the adrenal weight, and TUDCA and DHCA increased the spleen weight. The restraint stress induced increments in serum LDH, ALP and cholesterol were attenuated by most cholic acid derivatives. Cholic acid, taurocholic acid and tauroursodeoxycholic acid only increased the content of adrenal ascorbate. While valproic acid showed an inhibitory effect against stress, silymarin did not. Our findings suggest that most cholic acid derivatives have anti-stress effect and that their anti-stress effect is, in part, related to choleretic activity.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.137-146
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• 2006

Shear wave velocity of uncemented soil can be expressed as the function of effective stresses when capillary phenomenons are negligible. However, the terms of effective stresses are divided to the direction of wave propagation and polarization because stress states are generally anisotropy. The shear wave velocities are affected by parameters and exponents that are experimentally determined. The exponents are controlled contact effects of particulate materials(sizes, shapes, and structures of particles) and the parameters are changed contact behaviors between particles, material properties of particles, and type of packing(i.e., void ratio and coordination number). In this study, consolidation tests are performed by using clay, mica and sand specimens. Shear wave velocities are measured during consolidation tests to investigate the stress-induced and inherent anisotropies through bender elements. Results show the shear wave velocities depends on the stress-induced anisotropy for round particles. Furthermore the shear wave velocity is dependent on particle alignment under the constant effective stress. This study suggests that the shear wave velocity and the shear modulus should be carefully calculated and used for the design and construction of geotechnical structures.

• Molecules and Cells
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• 제38권10호
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• pp.851-858
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• 2015

Disturbed blood flow with low-oscillatory shear stress (OSS) is a predominant atherogenic factor leading to dysfunctional endothelial cells (ECs). Recently, it was found that disturbed flow can directly induce endoplasmic reticulum (ER) stress in ECs, thereby playing a critical role in the development and progression of atherosclerosis. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid, has long been used to treat chronic cholestatic liver disease and is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, its role in atherosclerosis remains unexplored. In this study, we demonstrated the anti-atherogenic activity of UDCA via inhibition of disturbed flow-induced ER stress in atherosclerosis. UDCA effectively reduced ER stress, resulting in a reduction in expression of X-box binding protein-1 (XBP-1) and CEBP-homologous protein (CHOP) in ECs. UDCA also inhibits the disturbed flow-induced inflammatory responses such as increases in adhesion molecules, monocyte adhesion to ECs, and apoptosis of ECs. In a mouse model of disturbed flow-induced atherosclerosis, UDCA inhibits atheromatous plaque formation through the alleviation of ER stress and a decrease in adhesion molecules. Taken together, our results revealed that UDCA exerts anti-atherogenic activity in disturbed flow-induced atherosclerosis by inhibiting ER stress and the inflammatory response. This study suggests that UDCA may be a therapeutic agent for prevention or treatment of atherosclerosis.

• 대한한의학방제학회지
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• 제30권2호
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• pp.85-93
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• 2022

Objectives : This study investigated anti-inflammatory effects of Nardotidis seu Sulculii Concha water extract (NSCE) against restraint-induced stress. Methods : In vivo, NSCE was orally administered to male white mice at concentrations of 250 mg/kg and 500 mg/kg for 3 days, and then restraint-induced stress was induced for 6 hours. The level of liver damage was measured by serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH). The stress-related hormones such as cortisol and corticosterone were measured by ELISA assay. Also, western blot analysis was performed to detect expression of mitogen-activated protein kinase (MAPK) and cyclooxygenase-2 (COX-2) proteins. Pathological changes were observed by hematoxylin and eosin (H&E) staining of the liver tissue, and Immunohistochemical (IHC) staining was performed to examine liver inflammation through macrophage infiltration. Results : The AST, ALT, LDH and the stress related hormones such as cortisol and corticosterone were significantly decreased in the NSCE treated group compared with stress group. In histological analysis, H&E staining of liver tissues did not detect the hepatic injury or damage in all groups. As a result of IHC staining, it was confirmed that infiltration of macrophages was increased in the stress-induced group, but decreased in the group treated with NSCE. The COX-2 and MAPK proteins expression was significantly increased by restraint-induced stress, but these proteins were decreased in the NSCE treated group. Conclusions : These results suggest that NSCE has the anti-inflammatory activity in restraint-induced stress model, and it is believed that NSCE can be used for the prevention of liver inflammation.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2002년도 봄 학술발표대회 발표논문집
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• pp.471-474
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• 2002

SA treatment significantly increased thermotolerance In cucumber seedlings. Pretreatment of seeds with $CaCl_2$ solution enhanced the SA- induced thermotolerance. On the contrary, pretreatment with the $Ca^{2+}$ chelator EGTA lowered this SA-induced thermotolerance. In addition, pretreatment with $Ca^{2+}$ channel blocker verapamil also weakened the SA-induced thermotolerance. However, the calmodulin antagonist chlorpromazine(CPZ) had little effect on the SA-induced thermotolerance. Measurement of activity of the antioxidant enzyme APX and the level of lipid peroxidation (in term of MDA) indicated that heat stress induced an oxidative stress in cucumber seedlings. SA treatment induced higher activities of APX and a lower level of lipid peroxidation. $Ca^{2+}$ pretreatment further enhanced the SA-induced increase in APX activity and lowered the heat stress-induced lipid peroxidation, but EGTA pretreatment had a contrary effect. These results suggest that $Ca^{2+}$ and calmodulin may be involved In the acquisition of the SA-induced thermotolerance; antioxidant enzyme system take part in the final generation of the SA-induced thermotolerance.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1877-1884
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• 2017

Mesenchymal stem cells (MSCs) have been suggested as a primary candidate for cell therapy applications because they have self-renewal and differentiation capabilities. Although they can be expanded in ex vivo system, clinical application of these cells is still limited because they survive poorly and undergo senescence or apoptosis when transplanted and exposed to environmental factors such as oxidative stress. Thus, reducing oxidative stress is expected to improve the efficacy of MSC therapy. The milk protein lactoferrin is a multifunctional iron-binding glycoprotein that plays various roles, including reduction of oxidative stress. Thus, we explored the effect of lactoferrin on oxidative stress-induced senescence and apoptosis of human MSCs (hMSCs). Measurement of reactive oxygen species (ROS) revealed that lactoferrin inhibited the production of hydrogen peroxide-induced intracellular ROS, suggesting lactoferrin as a good candidate as an antioxidant in hMSCs. Pretreatment of lactoferrin suppressed hydrogen peroxide-induced senescence of hMSCs. In addition, lactoferrin reduced hydrogen peroxide-induced apoptosis via inhibition of caspase-3 and Akt activation. These results demonstrate that lactoferrin can be a promising factor to protect hMSCs from oxidative stress-induced senescence and apoptosis, thus increasing the efficacy of MSC therapy.

• IMMUNE NETWORK
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• 제16권4호
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• pp.242-248
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• 2016

Thymic atrophy is a complication that results from exposure to many environmental stressors, disease treatments, and microbial challenges. Such acute stress-associated thymic loss can have a dramatic impact on the host's ability to replenish the necessary naïve T cell output to reconstitute the peripheral T cell numbers and repertoire to respond to new antigenic challenges. We have previously reported that treatment with the orexigenic hormone ghrelin results in an increase in the number and proliferation of thymocytes after dexamethasone challenge, suggesting a role for ghrelin in restraint stress-induced thymic involution and cell apoptosis and its potential use as a thymostimulatory agent. In an effort to understand how ghrelin suppresses thymic T cell apoptosis, we have examined the various signaling pathways induced by receptor-specific ghrelin stimulation using a restraint stress mouse model. In this model, stress-induced apoptosis in thymocytes was effectively blocked by ghrelin. Western blot analysis demonstrated that ghrelin prevents the cleavage of pro-apoptotic proteins such as Bim, Caspase-3, and PARP. In addition, ghrelin stimulation activates the Akt and Mitogen-activated protein kinases (MAPK) signaling pathways in a time/dose-dependent manner. Moreover, we also revealed the involvement of the FoxO3a pathway in the phosphorylation of Akt and ERK1/2. Together, these findings suggest that ghrelin inhibits apoptosis by modulating the stress-induced apoptotic signal pathway in the restraint-induced thymic apoptosis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.47-47
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• 2009

The formation of variable one-dimensional structures including core/shell structure is of particular significance with respect to potential applications for thermoelectric devices with the enhanced figure of merit ($ZT=S2{\sigma}T/{\kappa}$). We report the fabrication of Bi-Te core/shell nanowire based on a novel stress induced method. Fig. 1 schematically shows the nanowire fabrication process. Bi nanowires are grown on the Si substrate by the stress-induced method, and then Te is evaporated on the Bi nanowires. Fig. 2 is a transmission electron microscopy image clearly showing a core/shell structure for which effective phonon scattering and quantum confinement effect are expected. Electrical conductivity of the core/shell nanowire was measured at the temperatures from 4K to 300K, respectively. Our results demonstrate that Bi-Te core/shell nanowire can be grown successfully by the stress-induced method. Based on the result of electrical transport measurement and characteristic morphology of rough surface, Seebeck coefficient and thermal conductivity of Bi-Te core/shell nanowires are presented.

• 한국축산식품학회지
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• 제40권5호
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• pp.734-745
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• 2020

Commercially sterilized ultra high temperature (UHT) milk was manufactured at different homogenization pressures (20, 25, and 30 MPa), and changes in fat particle size, mechanical stress-induced fat aggregation, plasmin activity, and lipid oxidation were monitored during ambient storage of the UHT milk for up to 16 wk. The particle sizes of milk fat globules were significantly decreased as homogenization pressure increased from 20 to 30 MPa (p<0.05). The presence of mechanical stress-induced fat aggregates in milk produced at 20 MPa was significantly higher than for UHT milk produced at either 25 or 30 MPa. This difference was maintained all throughout the storage. There were no significant differences in plasmin activity, trichloroacetic acid (12%, w/v) soluble peptides, and the extent of lipid oxidation. Based on these results, an increase of homogenization pressure from 20 (the typical homogenization pressure employed in the Korea dairy industry) to 25-30 MPa significantly decreased mechanical stress-induced fat aggregation without affecting susceptibility to lipid oxidation during storage.

• 대한한의학방제학회지
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• 제30권3호
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• pp.155-163
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• 2022

Objectives : Lonicera japonica is known for anti-inflammation and antibiotic effect in Korean medicine. This study aimed for investigating the cytoprotective effect of Lonicera japonica extract (LJE) for HepG2 cells against arachidonic acid (AA)+iron-induced oxidative stress. Methods : The effect of LJE on cell viability was assessed by MTT assay. ROS assay was selected to assess antioxidant effect of LJE. To assess LJE's effect on mitochondrial function, flow cytometric analysis was operated. And immunoblot analysis was used to establish the underlying mechanism of LJE. Results : LJE protected HepG2 cells against AA+iron-induced oxidative stress by phosphorylation of liver kinase B1 and blocked the decline of procaspase 3. Also, LJE preserved the mitochondrial membrane permeability induced by AA+iron. Conclusion : LJE protected the hepatocyte from AA+iron-induced oxidative stress by activation of LKB1 by the preservation of mitochondrial functions.