• Title/Summary/Keyword: mediator effect

Search Result 745, Processing Time 0.03 seconds

The Effects of Service Employee's Surface Acting on Counterproductive Work Behavior: The Mediating Roles of Emotional Exhaustion (서비스 종업원의 표면행위가 반생산적 과업행동에 미치는 효과에 관한 연구: 감정소모의 매개효과를 중심으로)

  • Kang, Seong-Ho;Chay, Jong-Hak;Lee, Ji-Ae;Hur, Won-Moo
    • Journal of Distribution Science
    • /
    • v.14 no.2
    • /
    • pp.73-82
    • /
    • 2016
  • Purpose - Counterproductive work behavior(CWB) was typically categorized according to the behavior whether it targets other people(i.e., interpersonal CWB: I-CWB). Employing organizations(i.e., organizational CWB: O-CWB) has emerged as major concerns among researchers, managers, and the general public. An abundance of researches has informed us about the understanding for the antecedents of CWB, whereas little is known about the antecedents of CWB directed distribution service in employee's emotional labor. Therefore, the purpose of this research is to propose a research model in which surface acting enhances emotional exhaustion as an emotional labor strategy, which eventually increases counterproductive work behavior(including I-CWM and O-CWB). Research design, data, and methodology - This empirical research data were gathered from the samples of full time frontline hotel employees(including front office, call center, food/beverage, concierge, and room service) in South Korea. Six hotels were selected ranged from four to five stars, including privately owned and joint-venture properties. A convenience sampling method was used to select hotels. Full time frontline hotel employees from the six hotels were surveyed using a self-administered instrument for data collection. With the strong support of hotel managers, a total of 300 questionnaires were distributed, and 252 responses were collected indicating a response rate of 84.0%. In the process of working with the 252 samples, structural equation modeling is employed to test research hypotheses(H1: The relationship between surface acting and Interpersonal counterproductive work behavior(I-CWB) is mediated by emotional exhaustion, H2: The relationship between surface acting and organizational counterproductive work behavior(O-CWB) is mediated by emotional exhaustion). SPSS 18.0 and M-Plus 7.31 software were used for the data analysis. Descriptive statistics were used to assess the distribution of the employee profiles and correlations between factors. M-Plus 7.31 software was used to test the model fit, validity, and reliability of the factors, significance of the relationship between factors, and the effects of factors in the model. Results - To test our mediation hypotheses, we used an analytical strategy suggested by Preacher & Hayes (2008) and Shrout & Bolger (2002). This mediation approach directly tests the indirect effect between the predictor and the criterion variables through the mediator via a bootstrapping procedure. Thus, it addresses some weaknesses associated with the Sobel test. We found that surface acting was positively related to emotional exhaustion. Furthermore, emotional exhaustion was a significant predictor from the two kinds of counterproductive work behavior. In addition, surface acting was not significantly associated with the two kinds of counterproductive work behavior. These results indicated that the surface acting by frontline hotel employees was associated with higher emotional exhaustion, which is related with higher interpersonal counterproductive work behavior(I-CWB) and organizational counterproductive work behavior(O-CWB). In sum, we confirmed that the positive relationship between surface acting and the two kinds of counterproductive work behavior was fully mediated by emotional exhaustion. Conclusions - The current research broadens the conceptual work and empirical studies in counterproductive work behavior literature by representing a fundamental mechanism that how surface acting affects counterproductive work behavior.

The Effect of Antihistamine on Endotoxin-induced Acute Lung Injury (내독소 유도 급성폐손상에서 항히스타민의 역할)

  • Jung, Bock-Hyun;Koh, Youn-Suck;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
    • /
    • v.52 no.3
    • /
    • pp.219-229
    • /
    • 2002
  • Background : Sepsis-induced acute lung injury (ALI) is caused by many cellular and humoral mediators induced by an endotoxin. Histamine, which is widely distributed in the lungs and has been considered as an important mediator of sepsis. It increases P-selectin expression on the endothelial cell surfaces and induces IL-8 secretion. Therefore, an endotoxin-induced histamine may be related to neutrophil-mediated ALI by inducing the migration and activation of neutrophils in the lung tissue. However, the role of endogenous histamine in endotoxin ALI has not been clarified. The purpose of this study was to investigate how endotoxin-induced ALI is influenced by endogenous histamine and to identify the possible mechanism of action. Materials and Methods : The study consisted of 4 groups using Sprague-Dawley rats : 1) control group, where the rats were infused intratracheally by normal saline, 2) an endotoxin group, where lipopolysaccharide (LPS) was administered intratracheally 3) the $H_2$ receptor antagonist-treated group ($H_2$ group) and 4) the $H_1$ receptor antagonist-treated group ($H_1$ group), where $H_2$-receptor blocker (ranitidine) and $H_1$-receptor blocker(pyrilamine) were co-treated intravenously with the intratracheal administration of an endotoxin. The lung leak index using $I^{125}$-BSA, the total protein and LDH concentration in the lung lavage fluid, myeloperoxidase(MPO) activity in the lung tissue, the pathologic score and the total number of neutrophils, TNF-$\alpha$, IL-$1{\beta}$ and IL-10 in lung lavage (BAL) fluid were measured in each group as the indices of lung injury. Results : Compared to the control group, the endotoxin group exhibited significant increases in all lung injury indices. Significant reductions in the endotoxin-mediated increases in lung leak index (p<0.05) were observed in both the $H_1$ and $H_2$ groups. In addition the total protein (p<0.05) and LDH concentration (p<0.05) in the BAL fluid were also lower in the $H_2$ group compared to the endotoxin group. However, there was no change in the MPO activity in the lung tissue, the pathologic score and the total number of neutrophils in the BAL fluid in both the $H_2$ and $H_1$ groups compared to the endotoxin group. The increases in TNF-$\alpha$ IL-$1{\beta}$ and IL-10 concentrations in the BAL fluid observed in the endotoxin group were not reduced in the $H_2$ and $H_1$ groups. Conclusion : Antihistamine attenuated the enhanced alveolar-capillary permeability induced by the endotoxin via the $H_2$ receptor. However the attenuating mechanism may not be related to the pathogenesis of neutrophil dependent lung injury.

Biphasic Increase of Pro-inflammatory Cytokines in Mice Lung after Irradiation (방사선 조사 후 흰 쥐의 폐에서 염증성 Cytokine의 발현 양상)

  • Choi, Yun Jung;Rho, Jing Kyung;Jang, Won Seok;Lee, Seon Joo;Lee, Seung Sook;Koh, Jae Soo;Kim, Jae Yeol;Kim, Hye-Ryoun;Kim, Cheol Hyeon;Lee, Jae Cheol
    • Tuberculosis and Respiratory Diseases
    • /
    • v.67 no.1
    • /
    • pp.14-20
    • /
    • 2009
  • Background: The pathophysiologic mechanisms of radiation-induced lung injury should be elucidated to enhance the therapeutic efficacy of radiotherapy and to manage patients exposed to serious radiation by accident. It has been suggested that pro-inflammatory cytokines play an important role in radiation-induced effect on the lung. This study was aimed to investigate changes in pro-inflammatory cytokines such as TNF-$\alpha$, MIP-2, IL-1$\beta$ and HMGB1, a newly recognized inflammatory mediator. Methods: The chests of BALB/c mice were selectively irradiated with single fraction of 20 Gy and then sacrificed at indicated times. Pathologic changes in the lung were examined after H&E staining. The expression level of pro-inflammatory cytokines was evaluated by ELISA kits in lung homogenate and in serum. Results: Radiation induced inflammatory changes and mild fibrosis in lung. Biphasic increase of TNF-$\alpha$ and IL-1$\beta$ was found in lung homogenate at 4 hours and at 3 weeks after radiation. The elevation in the second phase tended to be more intense. However, there was no similar change in serum. MIP-2 level was slightly increased in lung homogenate at 4 hours, but not at 3 weeks. HMGB1 was increased at 3 weeks in serum while there was no significant change in lung homogenate. Conclusion: Radiation induced a biphasic increase in TNF-$\alpha$ and IL-1$\beta$. The effective control of second phase cytokine elevation should contribute to preventing severe lung fibrosis caused by radiation.

Polyamines Modulate Growth factor-Induced Membrane Protein Phosphorylation in MCF-7 Human Breast Cancer Cells (MCF-7 유방암세포에 있어서 growth factor에 의해 유도된 막 단백질의 인산화에 대한 폴리아민의 조절)

  • Lee, Ji-Young;Kim, Ji-Hyun;Lee, Kyeong-Hee;Kim, Byeong-Gee
    • Journal of Life Science
    • /
    • v.12 no.2
    • /
    • pp.164-172
    • /
    • 2002
  • Breast cancer cell lines display a wide variety of growth factor receptors, and considerable evidences implicate the importance of signalings from those receptors. A useful prognostic indicator would be the level of activity of a second messenger protein used in common by these receptors. Our studies were designed to obtain preliminary information on the possible role of polyamine as a mediator of the membrane-associated protein phosphorylation and as a regulator of second messenger in mitogenic signal of estrogen or growth factors in MCF-7 human breast lancer cells. DFMO significantly inhibited the phosphorylation induced by $E_2$, TGF-$\alpha$ and EGF in membrane-associated proteins (154, 134, 116, and 104 kDa). Exogenous polyamines abolished the inhibitory effect of DFMO. Tyrosine phosphorylations of membrane-associated proteins were not increased by $E_2$ or growth factor treatments and not affected DFMO treatment. Polyamine administration markedly enhanced the tyrosine phosphorylation of membrane-associated proteins (154, 134, and 116 kDa). In the present study, $E_2$ and TGF-$\alpha$ and EGF enhanced protein phosphorylation in the almost same levels. These data indicate that $E_2$ and growth factor signaling pathway may cross-talk through various protein kinase which phosphorylated many substrate proteins (154, 134, 116 and 104 kDa). Polyamines may be involved in growth signaling pathway of $E_2$ and TGF-$\alpha$ or EGF for the cross-talk through regulation of the protein phosphorylation such as 154, 134, 116 and 104 kDa. Polyamine may also selectively interfere with several different protein kinases, and the specific steps in signal transduction system were effected by polyamines.

Destabilization of TNF-α mRNA by Rapamycin

  • Park, Jong-Woo;Jeon, Ye-Ji;Lee, Jae-Cheol;Ahn, So-Ra;Ha, Shin-Won;Bang, So-Young;Park, Eun-Kyung;Yi, Sang-Ah;Lee, Min-Gyu;Han, Jeung-Whan
    • Biomolecules & Therapeutics
    • /
    • v.20 no.1
    • /
    • pp.43-49
    • /
    • 2012
  • Stimulation of mast cells through the high affinity IgE receptor (Fc${\varepsilon}$RI) induces degranulation, lipid mediator release, and cytokine secretion leading to allergic reactions. Although various signaling pathways have been characterized to be involved in the Fc${\varepsilon}$RI-mediated responses, little is known about the precious mechanism for the expression of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in mast cells. Here, we report that rapamycin, a specific inhibitor of mammalian target of rapamycin (mTOR), reduces the expression of TNF-${\alpha}$ in rat basophilic leukemia (RBL-2H3) cells. IgE or specific antigen stimulation of RBL-2H3 cells increases the expression of TNF-${\alpha}$ and activates various signaling molecules including S6K1, Akt and p38 MAPK. Rapamycin specifically inhibits antigeninduced TNF-${\alpha}$ mRNA level, while other kinase inhibitors have no effect on TNF-${\alpha}$ mRNA level. These data indicate that mTOR signaling pathway is the main regulation mechanism for antigen-induced TNF-${\alpha}$ expression. TNF-${\alpha}$ mRNA stability analysis using reporter construct containing TNF-${\alpha}$ adenylate/uridylate-rich elements (AREs) shows that rapamycin destabilizes TNF-${\alpha}$ mRNA via regulating the AU-rich element of TNF-${\alpha}$ mRNA. The antigen-induced activation of S6K1 is inhibited by specific kinase inhibitors including mTOR, PI3K, PKC and $Ca^{2+}$chelator inhibitor, while TNF-${\alpha}$ mRNA level is reduced only by rapamycin treatment. These data suggest that the effects of rapamycin on the expression of TNF-${\alpha}$ mRNA are not mediated by S6K1 but regulated by mTOR. Taken together, our results reveal that mTOR signaling pathway is a novel regulation mechanism for antigen-induced TNF-${\alpha}$ expression in RBL-2H3 cells.

The Change of Alveolar-capillary Barrier by Germanium in Acute Lung Injury Induced by Lipopolysaccharide (LPS에 의한 급성 폐손상에서 게르마늄에 의한 폐포-모세혈관 장벽의 변화)

  • Lee, Yoon-Jeong;Cho, Hyun-Gug;Sin, Gun-Ho;Jeune, Kyung-Hee
    • Applied Microscopy
    • /
    • v.39 no.1
    • /
    • pp.27-40
    • /
    • 2009
  • Acute respiratory distress syndrome (ARDS), also known as an acute inflammatory lung disease is developed by various factors that is originated from the destruction of alveolar-capillary barrier, and neutrophils plays an important role in the destruction. The study intended to confirm, the anti-inflammatory effect of germanium, whether a lung injury has been mitigated with the reduction of injury in alveolar-capillary barrier resulting from inhibition of neutrophils migration in lung tissue. Test groups were divided in saline administered CON, 5 hours of endotoxin administered LPS and 5 hours of endotoxin administered Ge+LPS following 1 hours of pre-processed germanium. $100{\mu}g$ endotoxin was melted in 0.5 mL saline and sprayed into airway and 26 mg germanium per 100 g weight was administered into abdominal cavity. The endotoxin group which induced an acute lung injury with administered endotoxin showed dramatic increase of pulmonary edema (p<0.001), protein contents in bronchoalveolar lavage fluid, BALF (p<0.05) and neutrophils of infiltration in BALF (p<0.001) comparing with a control group, while a pre-treated germanium group showed significant decrease in all categories comparing to the endotoxin administerd group. In the result of a microscopic observation, the structure of alveolar-capillary barrier which is constructed with basal lamina, alveolar type I cells and endothelial cell were preserved of the pre-treated germanium group relatively well compare to the endotoxin administered group. And the construction of lamellar body, microvilli and basal lamina of alveolar type II cells were also preserved relatively well. Hence, germanium activates as an anti-Inflammatory mediator in other words, it interfered neutrophils migration into lung tissue, thereby reduced injury of alveolar-capillary barrier from toxic substances of activated neutrophils. Consequently, the study has determined that the acute lung injury induced by endotoxin has been decreased by the pre-treated germanium.

Effects of 20(S)-Protopanaxadiol and 20(S)-Protopanaxatriol on the Inflammatory Mediators Release from the Activated Mast Cells (20(S)-Protopanaxadiol 및 20(S)-Protopanaxatriol이 활성화된 비만세포로부터의 염증 매개체 유리에 미치는 영향)

  • Ro, Jai-Youl;Han, Yong-Nam;Choi, Kwang-Tae;Lee, Chang-Ho
    • Journal of Ginseng Research
    • /
    • v.33 no.4
    • /
    • pp.316-323
    • /
    • 2009
  • Ginseng saponins have various pharmacological effects on the immune system. 20(S)-protopanaxadiol (PPD) and 20(S)-protopanaxatriol (PPT) are the species of ginseng saponin metabolites that are formed by human intestinal bacteria and detected in circulation. The effects of PPD and PPT on the inflammatory mediator release from the activated mast cells were tested. Histamine release was evaluated in activated guinea pig lung mast cells, and the secretion of interleukin-4 (IL-4), interleukin-8 (IL-8), and the tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) was assessed in an HMC-1 cell after treating it with ginseng saponin metabolites. The results are as follows. PPT, at its maximum concentration of $100\;{\mu}M$, completely abolished the secretion of IL-4 from the PMA-stimulated HMC-1 cell. It also inhibited IL-8 secretion from the same cells by about 40-50% of the PMA-treated DMSO control. PPD, at its maximum concentration of $100\;{\mu}M$, showed a tendency to induce histamine release from the guinea pig lung mast cells. It inhibited the secretion of IL-4 (by 89% of the PMA-treated DMSO control) in the PMA-stimulated HMC-1 cell, but did have a significant effect on the IL-8 release from the same cell. Both PPD and PPT showed no effects, however, on the release of TNF-${\alpha}$ from the PMA-stimulated HMC-1 cell. These results suggest that PPD and PPT are from the ginseng metabolites that are responsible for the immunomodulating activity of ginseng extracts when they are taken orally.

Inhibitory Effects of Euphorbia supina Rafin on the Production of Pro-Inflammatory Mediator by LPS-Stimulated RAW 264.7 Macrophages (LPS로 활성화된 RAW 264.7 대식세포에서 애기땅빈대(Euphorbia supina Rafin)의 염증매개물질 억제효과)

  • Park, Sung-Chul;Son, Dae-Yeul
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.40 no.4
    • /
    • pp.486-492
    • /
    • 2011
  • This study was designed to evaluate the effect of hot water extract (ESW) and 70% ethanol extract (ESE) from Euphorbia supina Rafin on LPS-stimulated inflammatory response in RAW 264.7 macrophages. Upon investigation at concentrations up to $1000\;{\mu}g$/mL, ESW and ESE did not have any cytotoxic effects on RAW 264.7 macrophages. ESW induced inhibition of 21.6%~54.8% of nitric oxide (NO) production at 100~1000${\mu}g$/mL, and $PGE_2$ production was inhibited up to 25.7%~38.2% at 250~1000${\mu}g$/mL, proportional to the ESW concentrations. ESW induced inhibition of 66.1% and 54.3% of IL-6 production at 250 and $1000\;{\mu}g$/mL, respectively. ESE (100~1000${\mu}g$/mL) induced inhibition of 38.3%~77.5% of NO, 40%~94.7% of $PGE_2$, and 43.9%~89.4% of IL-6 production, proportional to the ESE concentrations. Only 44.1% of IL-10 production was inhibited at a concentration of $500\;{\mu}g$/mL. ESE induced an increase in TNF-${\alpha}$ production at a concentration of 100 and $250\;{\mu}g$/mL, whereas at high concentrations (500 and $1000\;{\mu}g$/mL), ESE induced inhibition of 19.2% and 92.4% of TNF-${\alpha}$ production, respectively. In conclusion, concentrations of more than $500\;{\mu}g$/mL ESE demonstrated effective immune-modulating activity through inhibition of NO, $PGE_2$, IL-6, IL-10, or TNF-${\alpha}$ production, as it relates to the macrophage's immuno-activity; therefore, ESE has potential as a good candidate substance for reduction of inflammatory responses.

Comparative Evaluation on Sperm Parameter of Transgenic Pigs with General Pigs (형질전환 돼지의 정자와 일반돼지의 정자성상에 대한 비교평가)

  • Park, Sang Hyoun;Lee, Gunsup;Lee, Joo Yung;Kim, Kyung Woon;Byun, Sung-June;Ock, Sun A;Hwang, Seongsoo;Yang, Hyeon;Woo, Jae-Seok;Oh, Keon Bong
    • Journal of Embryo Transfer
    • /
    • v.32 no.3
    • /
    • pp.227-233
    • /
    • 2017
  • Pig has been known to be one of the most feasible animals as a bioreactor to produce pharmaceuticals in milk and as a mediator in xenotransplantation research. Previously, we generated transgenic pigs for both purposes, which were expressing Factor 8, vWF, hTPA, and hEPO in milk, along with expression of MCP at GalT gene locus ($GalT^{-MCP/-MCP}$) as well as expressing MCP at GalT gene loci with CD73 expression ($GalT^{-MCP/+}/CD73$). In this study, we performed comparative analyses of sperm parameters between wild type male (WT) pig and those transgenic males to examine the effects of transgenes integrated into the pigs on motility, morphology, viability, and acrosome integrity of the spermatozoa. Our results showed that the rates of actively motile spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, $GalT^{-MCP/+}/CD73$, and $GalT^{-MCP/-MCP}$ pigs were 85.0%, 83.3%, 82.5%, 83.3%, 82.5%, 77.5%, and 78.7%, respectively. Whereas, the rates of morphologically normal spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, $GalT^{-MCP/+}/CD73$, and $GalT^{-MCP/-MCP}$ pigs were 90.0%, 80.0%, 80.0%, 83.3%, 85.0%, 91.8%, and 80.8%, respectively. In addition, the viability in spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, $GalT^{-MCP/+}/CD73$, and $GalT^{-MCP/-MCP}$ pigs were 93.9%, 82.4%, 89.9%, 83.9%, 87.4%, 92.8%, and 83.6%, respectively. The rates of spermatozoa with normal acrosome integrity in WT, Factor 8, vWF, hTPA, hEPO, $GalT^{-MCP/+}/CD73$, and $GalT^{-MCP/-MCP}$ pigs were 98.1%, 98.6%, 98.6%, 98.7%, 98.1%, 99.5%, and 95.1%, respectively. There were no significant differences in motility, morphology, viability, and acrosome integrity of the spermatozoa among WT, Factor 8, vWF, hTPA, and hEPO, $GalT^{-MCP/+}/CD73$, and $GalT^{-MCP/-MCP}$ pigs. These mean that neither random integration nor targeted integration of the transgene into chromosome of pig effect on characteristics of spermatozoa. Ultimately, the transgenic male pigs subjected in this study could apply to propagate their progenies for production of human therapeutic proteins and advancing the xenotransplantation research.

A Study on the Factors Affecting the Entrepreneurial Intentions of Manufacturing Industry Employees: Focused on the Effects of Entrepreneurship and Personal Characteristics (중소 제조업 종사자의 창업의도에 미치는 영향 요인에 관한 연구: 기술개발 지원사업의 조절효과를 중심으로)

  • Shin, Yong-Sik;Kim, Jae-Hong;Lee, Il-han
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.16 no.4
    • /
    • pp.135-151
    • /
    • 2021
  • This research attempts to analyze the factors influencing the entrepreneurial intention of employees in manufacturing field. In particular, key factors of entrepreneurship and personal characteristics explain a significant association with the intention to start-up. And study whether R&D support from public enterprise adjusts intention to entrepreneurial Intention. This study conducted a online survey on 292 small and medium-sized enterprise manufacturing employees in May 2020. Using linear regression model and binary logistic model. The main study results are the following: First, among the key factors(innovativeness, proactiveness, risk-taking) of entrepreneurship, proactiveness hardly influenced the opportunity competency. Second, among the factors(risk-taking propensity, locus of control, tolerance for ambiguity) of personal characteristics, locus of control hardly influenced the opportunity competency. Third, opportunity competency(opportunity recognition and opportunity evaluation) had positive influence to entrepreneurial intention. Fourth, the study investigated the mediated effect of opportunity competency. The result showed that among the factors of entrepreneurship and personal characteristics, only two factors that are proactiveness and locus of control were not mediated by opportunity competency. and opportunity evaluation was acted as a mediator between proactiveness and entrepreneurial Intention, compared with opportunity recognition. Lastly, public enterprise's R&D supporting moderated the entrepreneurial intention). Based on the result, the study showed that first, the key factors of entrepreneurship except for proactiveness and personal characteristics(risk-taking propensity, locus of control, tolerance for ambiguity) except for locus of control affect the intention to start-up, repeatedly. This results are explained that employees have not started a business yet. Second, research on start-up suggests the need to analyze factors differentiated before and after the start-ups. Based on the results, entrepreneurship and personal characteristics show that study on the effects of start-up intentions should be carried out before and after the actual start-up takes place, and can be used as effective data in policies to promoting start-ups in manufacturing field.