• Korean Journal of Medicinal Crop Science
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• v.28 no.2
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• pp.85-94
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• 2020

Background: Alzheimer's disease (AD) is caused by various factors, such as cholinergic dysfunction, regulation of neurotrophic factor expression, and accumulation of amyloid-beta. We investigated whether or not a combination of Carthamus tinctorius L. seed and Taraxacum coreanum (CT) has a protective effect on scopolamine-induced memory impairment in a mouse model. Methods and Results: Mice were orally pretreated with CT (50, 100 and 200 mg/kg/day) for 14 days, and scopolamine (1 mg/kg/day) was injected intraperitoneally before subjecting them to behavior tests. CT-administered mice showed better novel object recognition and working memory ability than scopolamine-treated control mice. In T-maze and Morris water maze tests, CT (100 and 200 mg/kg/day) significantly increased space perceptive ability and occupancy to the target quadrant, respectively. In addition, 100 and 200 mg/kg/day of CT attenuated cholinergic dysfunction through inhibition of butyryl cholinesterase in brain tissue. Furthermore, CT-administered mice showed higher cyclic adenosine monophosphate-response element-binding protein (CREB) levels and lower amyloid precursor protein (APP) levels compared to scopolamine-treated control mice. Conclusions: CT improved scopolamine-induced memory impairment through inhibition of cholinergic dysfunction, up-regulation of CREB, and down-regulation of APP. Therefore, CT could be a useful therapeutic agent for AD with protective effects on cognitive impairment.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.507-514
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• 2015

There is an increasing awareness about the abusive supervision(AS) and organizational silence(OS) in organizations and literature about the relation between organizational commitment(OC). But there is a shortage of studies about the abusive supervision and organizational silence in travel service. The purpose of this study is to research reasons of abuse supervision in organizations, its effects, results and applications which can minimize or remove abusive supervision by discussion. In this sense, Questionnaires were delivered 9 travel agencies in Seoul and 241 of them were taken. Questionnaire data was analyzed, and according to the results, some implications were proposed. Abusive supervision affects on organizational silence and organizational commitment of employee in travel agent. Organizational silence ha positive effects on organizational commitment. Organizational silence plays as a role of mediator variable in proposal research model. It is hoped that the present research will encourage future multi-level theoretical and empirical work on abusive supervision.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.50-58
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• 2006

Translationally controlled tumor protein (TCTP), also known as histamine releasing factor (HRF), is found abundantly in different eukaryotic cell types. The sequence homology of TCTP between different species is very high, belonging to the MSS4/DSS4 superfamily of proteins. TCTP is involved in both cell growth and human late allergy reaction, as well as having a calcium binding property; however, its primary biological functions remain to be clearly elucidated. In regard to many possible functions, the TCTP of Plasmodium falciparum (Pf) is known to bind with an antimalarial agent, artemisinin, which is activated by heme. It is assumed that the endoperoxide-bridge of artemisinin is opened up by heme to form a free radical, which then eventually alkylates, probably to the Cys14 of PfTCTP. Study of the docking of artemisinin with heme, and subsequently with PfTCTP, was carried out to verify the above hypothesis on the basis of structural interactions. The three dimensional (3D) structure of PfTCTP was built by homology modeling, using the NMR structure of the TCTP of Schizosaccharomyces pombe as a template. The quality of the model was examined based on its secondary structure and biological function, as well as with the use of structure evaluating programs. The interactions between artemisinin, heme and PfTCTP were then studied using the docking program, FlexiDock. The center of the peroxide bond of artemisinin and the Fe of heme were docked within a short distance of $2.6{\AA}$, implying the strong possibility of an interaction between the two molecules, as proposed. When the activated form of artemisinin was docked on the PfTCTP, the C4-radical of the drug faced towards the sulfur of Cys14 within a distance of $2.48{\AA}$, again suggesting the possibility of alkylation having occurred. These results confirm the proposed mechanism of the antimalarial effect of artemisinin, which will provide a reliable method for establishing the mechanism of its biological activity using a molecular modeling study.

• Archives of Pharmacal Research
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• v.26 no.1
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• pp.83-88
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• 2003

KR-984055 is a new oral cephalosporin antibiotic with activity against both gram-positive and gram-negative bacteria. Lipophilic ester-type prodrugs of KR-984055, i.e., KR-999001 and KR-999002, have been synthesized in an attempt to increase the oral bioavailability of this broad-spectrum antibiotic agent. In this study we determined the oral bioavailability of KR-984055 and its prodrugs in the rat, and evaluated the pharmacokinetic model that best describes the plasma concentration behavior following single intravenous (IV) and oral single dose. In addition, concentrations in plasma as well as biliary and urinary recovery of KR-984055 were determined. Also, protein binding of KR-984055 in plasma was examined in vitro. The degree of protein binding of KR-984055 was in the range of 92.09~94.77%. KR-984055 exhibited poor oral bioavailability (7.02$\pm$1.58%). The observed oral bioavailabilities of KR-984055 from KR-999001 and KR-999002 were 38.77$\pm$2.81 % and 39.81$\pm$5.25%, respectively. These data were calculated from the levels of free KR-984055 in plasma. Oral KR-999001 and KR-999002 were not recovered from plasma, suggesting that it was readily cleaved to free KR-984055. KR-999001 and KR-999002 appear to be an efficient oral prod rug of KR-984055 that deserved further clinical evaluation in human.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.21-36
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• 2015

These days Automated Vehicle(AV) has been receiving attention as a fundamental solution to resolve the various transportation problems and various researches related to the benefits of AV have been done. However, previous researches mainly analyzed the effects in the virtual network. The purpose of this research is to predict and to find out the benefits by introducing the Automated Vehicle to present road traffic system. Thus, the study analyzes the traffic-flow changes of Gyeongbu freeway Seoul-Singal basic section which is planned for setting the test-bed. The results show that Automated Vehicle can have negative effects on the traffic-flow in low volume of LOS A and B. However, the average speed increases and the traffic density decreases in more than LOS C, the traffic volume increase. Therefore, the introduction of Automated Vehicle achieves positive effect on various transportation problems such as the traffic congestion.

• Survey Research
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• v.1 no.2
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• pp.59-87
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• 2000

The hypothesis of this study is that change acceptance and work adaptation of change agents are influenced by positive self-image and risk tolerance. In order to examine the hypothesis, this study was performed with 305 change agents from six branches of a conglomerate company. Specifically, self-image was measured by locus of control, self-efficacy, self-esteem, and positive affectivity; risk tolerance was measured by tolerance for ambiguity, risk aversion, and openness to experience. The result of this study indicated that self-image and risk tolerance significantly predicted change acceptance and work adaptation. Especially, the results of structural model revealed that change acceptance mediated the relationship between characteristic variables (such as self image and risk tolerance in this study) and work adaptation. Based on the results, we suggest that change agents keep developing positive self-image and risk tolerance in order to play the key role in leading organizational change.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.5
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• pp.169-178
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• 2014

In this paper, we present a research utilizing decentralized LTL specifications for ensuring a quality for interaction-centralized system. In this system, for ensuring the quality, we need to validate interactions between modules of the system and then we should check whether the system achieves the expected requirements. This task remains difficult and labor-intensive and requires an expert. In this paper, we present a method to assist such a task. First of all, the requirements of the system is written as multiple LTL specifications. Interactions between modules mean that behaviors of one module are related with other one's behavior. We generate the automaton model fully achieving specification through GR(1) synthesis. And we simulate them using the simulator based on the software agent for checking behaviors of the system. Finally, we validate the whole system whether it achieves given requirements.

• BMB Reports
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• v.37 no.2
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• pp.239-245
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• 2004

We have previously demonstrated that the redox reactant pyruvate prevents apoptosis in the oxidant model of bovine pulmonary artery endothelial cells (BPAEC), and that the anti-apoptotic mechanism of pyruvate is mediated in part via the mitochondrial matrix compartment. However, cytosolic mechanisms for the cytoprotective feature of pyruvate remain to be elucidated. This study investigated the pyruvate protection against endothelial cytotoxicity when the glycolysis inhibitor 2-deoxy-D-glucose (2DG) was applied to BPAEC. Millimolar 2DG blocked the cellular glucose uptake in a concentration- and time-dependent manner with >85% inhibition at $\geq$5 mM within 24 h. The addition of 2DG evoked BPAEC cytotoxicity with a substantial increase in lipid peroxidation and a marked decrease in intracellular total glutathione. Exogenous pyruvate partially prevented the 2DG-induced cell damage with increasing viability of BPAEC by 25-30%, and the total glutathione was also modestly increased. In contrast, 10 mM L-lactate, as a cytosolic reductant, had no effect on the cytotoxicity and lipid peroxidation that are evoked by 2DG. These results suggest that 2DG toxicity may be a consequence of the diminished potential of glutathione antioxidant, which was partially restored by exogenous pyruvate but not L-lactate. Therefore, pyruvate qualifies as a cytoprotective agent for strategies that attenuate the metabolic dysfunction of the endothelium, and cellular glucose oxidation is required for the functioning of the cytosolic glutathione/NADPH redox system.

• Journal of Ginseng Research
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• v.39 no.4
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• pp.304-313
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• 2015

Background: Ginsenoside Rg3 is a promising anticancer agent. It is usually produced by heat treatment of ginseng, in which ginsenoside Rb1 is the major ginsenoside. A kinetic study was conducted to optimize ginsenoside Rg3 production by the heat treatment of ginsenoside Rb1. Methods: Ginsenoside Rb1 was heated using an isothermal machine at $80^{\circ}C$ and $100^{\circ}C$ and analyzed using HPLC. The kinetic parameters were calculated from the experimental results. The activation energy was estimated and used to simulate the process. The optimized parameters of ginsenoside Rg3 production are suggested based on the simulation. Results: The rate constants were $0.013h^{-1}$ and $0.073h^{-1}$ for the degradation of ginsenosides Rb1 and Rg3 at $80^{\circ}C$, respectively. The corresponding rate constants at $100^{\circ}C$ were $0.045h^{-1}$ and $0.155h^{-1}$. The estimated activation energies of degradation of ginsenosides Rb1 and Rg3 were 69.2 kJ/mol and 40.9 kJ/mol, respectively. The rate constants at different temperatures were evaluated using the estimated activation energies, and the kinetic profiles of ginsenosides Rb1 and Rg3 at each temperature were simulated based on the proposed kinetic model of consecutive reaction. The optimum strategies for producing ginsenoside Rg3 from ginsenoside Rb1 are suggested based on the simulation. With increased temperature, a high concentration of ginsenoside Rg3 is formed rapidly. However, the concentration decreases quickly after the reaching the maximal concentration value. Conclusion: The optimum temperature for producing ginsenoside Rg3 should be the highest temperature technically feasible below $180^{\circ}C$, in consideration of the cooling time. The optimum reaction time for heat treatment is 30 min.

• YAKHAK HOEJI
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• v.59 no.6
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• pp.259-265
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• 2015

In recent, there are increasing reports about pharmacological activities of Crataegi Fructus which has been used for many centuries as medicinal and food sources in East Asia. However, its antifungal efficacy needs to be investigated. Thus, in the current study, we determined synergistic antifungal activity of the Crataegi Fructus extract (CFE) when combined with fluconazole (FLC) against disseminated candidiasis due to Candida albicans. This fungus is one of the most problematic fungal pathogens. Data resulting from a microdilution susceptibility test showed that CFE had a dose-dependent antifungal activity. When the extract was combined with FLC, the activity was synergistic. For example, the antifungal activity by the combination of CFE at $20{\mu}g/ml$ plus FLC at $0.1{\mu}g/ml$ was 4 times more effective than antifungal activity by FLC alone at the same concentration (P<0.05). In the murine model of disseminated candidiasis, the combination therapy potentiated resistance of mice, resulting in 80% of C. albicans-infected animals surviving the entire period of 40 days observation, whereas mice given CFE alone or FLC alone all died with 17 and 23 days, respectively, although they survived longer than the untreated control animals (P<0.05). The CFE's antifungal activity seemed to be related to the blockage of hyphal production of C. albicans yeast cells. In summary, CFE has a synergistic antifungal activity, which can be produced by combining CFE with FLC. Thus, our data strongly indicate that CFE may be a potential candidate as an antifungal agent for combination therapy.