• Radiation Oncology Journal
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• v.23 no.1
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• pp.51-60
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• 2005

Purpose : Selective inhibition of multiple molecular targets may improve the antitumor activity of radiation. Two specific inhibitors of selective cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) were combined with radiation on the HeLa cell line. To investigate cooperative mechanism with selective COX-2 inhibitor and EGFR blocker, in vitro experiments were done. Materials and Methods : Antitumor effect was obtained by growth inhibition and apoptosis analysis by annexin V-Flous method. Radiation modulation effects were determined by the clonogenic cell survival assay. Surviving fractions at 2 Gy ($SF_2$) and dose enhancement ratio at a surviving fraction of 0.25 were evaluated. To investigate the mechanism of the modulation of radiosensitivity, the cell cycle analyses were done by flow cytometry. The bcl-2 and bax expressions were analyzed by western blot. Results : A cooperative effect were observed on the apoptosis of the HeLa ceil line when combination of the two drugs, AG 1478 and NS 398 with radiation at the lowest doses, apoptosis of $22.70\%$ compare with combination of the one drug with radiation, apoptosis of $8.49\%$. In cell cycle analysis, accumulation of cell on $G_0/G_l$ phase and decrement of S phase fraction was observed from 24 hours to 72 hours after treatment with radiation, AG 1478 and NS 398. The combination of NS 398 and AG 1478 enhanced radiosensitivity on a concentration-dependent manner in HeLa cells with dose enhancement ratios of 3.00 and $SF_2$ of 0.12 but the combination of one drug with radiation was not enhanced radlosensitivity with dose enhancement ratios of 1.12 and SF2 of 0.68 (p=0.005). The expression levels of bcl-2 and bax were reduced when combined with AG 1478 and NS 398. Conclusion : Our results indicate that the selective COX-2 inhibitor and EGFR blocker combined with radiation have potential additive or cooperative effects on radiation treatment and may act through various mechanisms including direct inhibition of tumor cell proliferation, suppression of tumor cell cycle progression and inhibition of anti-apoptotic proteins.

• The Journal of Korean Medicine
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• v.32 no.6
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• pp.18-29
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• 2011

Objectives: To investigate anti-inflammatory and anti-arthritic effects of Gyulpidaehwangbakcho-tang (GDBT) extract in a murine model of rheumatoid arthritis. Methods: The mice received $100{\mu}g$ of bovine type II collagen in Freund's complete adjuvant by intradermal injection at the base of the tail on day 0 and a booster injection on day 21. The mice were orally administered with GDBT (200 or 50mg/kg dissolved in distilled water) daily from day 1 to day 21 after arthritis incidence, and monitored for disease incidence and the severity of arthritis up to day 21. In order to evaluate the effect of GDBT on disease progression, we examined pro-inflammatory cytokines including IL-$1{\beta}$, IL-6, TNF-${\alpha}$, COX-2 and NOS-II. Results: GDBT produced a significant and dose dependent inhibition of arthritis and inflammation during the entire duration of the study. This action was characterized by the decreased production of IL-$1{\beta}$, IL-6, TNF-${\alpha}$, COX-2, and NOS-II in vivo. Conclusion: We believe that the anti-arthritic activity of GDBT is due to its modulatory effect on the expression of pro-inflammatory cytokine in the synovium. Our results contribute towards validation of the traditional use of GDBT in the treatment of RA and other inflammatory joint disorders.

• Journal of Korean Critical Care Nursing
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• v.3 no.2
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• pp.1-11
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• 2010

Purpose: This study was designed to identify the factors affecting healing of Stage 2 pressure ulcer in an acute care facility in Korea. Methods: 286 Stage 2 pressure ulcers of 145 patients were examined. Data were collected in the period between October $1^{st}$, 2006 and September $30^{th}$, 2007. Data were analyzed with Kaplan-Meier survival analysis for cumulative recovery rate of Stage 2 pressure ulcers. Cox proportional hazard model was used to examine effects of multiple variables simultaneously. Results: Out of 286 initial Stage 2 pressure ulcers, 204 (71.3%) pressure ulcers healed completely. The median time to heal was 15 days according to Kaplan-Meier survival analysis. Cox proportional hazard model showed that the Stage 2 pressure ulcers healed more quickly when pressure redistribution surfaces were used (p<.001, HR=2.184), patients were administered with vitamins (p= .038, HR=1.451), and the size of the pressure ulcers were small (${\leq}3.0cm^2$, p= .006, HR=1.765). Conclusion: The factors contributing to the healing of Stage 2 pressure ulcer in an acute care setting were the application of pressure redistribution surface, small ulcer size (${\leq}3.0cm^2$), and the administration of vitamins.

• Journal of the Korean Data and Information Science Society
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• v.21 no.2
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• pp.201-209
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• 2010

Due to the dramatic increase of mortality from ischemic heart disease (IHD) during the last decade, it is highly warranted to present the effective prevention strategy. Therefore this study identified the major risk factors of IHD over 10 years of follow-up among 2,268,018 participants of National Health Insurance Exam in 1996 with Cox proportional hazard model. In men, BMI, blood pressure, smoking were significantly associated with IHD, whereas hypertension, perceived health status and ${\gamma}$-GTP were related with IHD in women.

• Journal of Korea Planning Association
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• v.54 no.2
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• pp.5-16
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• 2019

The purpose of this study is to analyze the spatial characteristics of business-type-changed parcel in the Hongik-University commercial area, from the view point of commercial gentrification. A commercial gentrification occurs through a business-type-change in a spatial basic unit (microscopic spatial unit such as parcel) of an area which has not been considered in relavent policies and research. So, this study analyzed the spatial characteristics of business-type-changed parcels using the Cox's proportional hazard regression model. The main results of this study are as follows. First, as new developments in the adjacent area occur, the business-type-change probability increases. Second, by the commercial area division, the business-type-change probability is different. Finally, the accessibility is better, the probability is higher. These results could suggest that a consideration of the spatial characteristics form microscopic viewpoint is necessary to understand the commercial gentrification. And these could be used as basic data for a gentrification diagnostic and management system, which can predict gentrification from the view point of business-type-change on the basis of a parcel.

• Journal of Korean Society for Quality Management
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• v.18 no.1
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• pp.9-20
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• 1990

The purpose of this paper is to propose the modified semiparametric estimators for survival function in the Cox's regression model with randomly censored data based on Tsiatis and Breslow estimators, and present their asymptotic variances estimates. The proposed estimators are compared to Tsiatis, Breslow, and Kaplan-Meier estimators through a small-sample Monte Carlo study. The simulation results show that the proposed estimators are preferred for small sample sizes.

• Journal of the Korean Statistical Society
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• v.20 no.1
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• pp.85-92
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• 1991

A set of conditions ensuring local asymptotic normality for independent but not necessarily identically distributed observations in semiparametric models is presented here. The conditions are turned out to be more direct and easier to verify than those of Oosterhoff and van Zwet(1979) in semiparametric models. Examples considered include the simple linear regression model and Cox's proportional hazards model without censoring where the covariates are not random.

• Journal of the Korean Data and Information Science Society
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• v.16 no.2
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• pp.271-281
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• 2005

Zokian(1993) and Li and Li(1996) developed TARCH(Threshold ARCH) model, considering the asymmetries in volatility. The models are based on Engle(1982)'s ARCH model and Bollerslev(1986)'s GARCH model. However, two TARCH models can be expressed a common model through Box Cox Power transformation, which was used by Higgins and Bera(1992) for developing NARCH(nonlinear ARCH) model. This article shows the PTARCH(Power transformation TARCH) model is necessary in some condition, and it checks the fact that PTARCH model has better performance comparing estimates and RMSE(Root Mean Square Error) with those of Zakoian's TARCH model and Li and Li's TARCH model. PTARCH model would give contribution in asymmetric study as well as heteroscedastic study.

• Korea Real Estate Review
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• v.28 no.3
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• pp.21-35
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• 2018

The recent performance of residential mortgages demonstrated how default risk operated separately from prepayment risk. In this study, we investigated the determinants of the borrowers' decisions pertaining to early termination through default from the mortgage performance data released by Freddie Mac, involving securitized mortgage loans from January 2011 to September 2013. We estimated a Cox-type, proportional hazard model with a single risk on fundamental factors associated with default options for individual mortgages. We proposed a mortgage default model that included two specifications of delinquency: one using a delinquency binary variable, while the other using a delinquency probability. We also compared the results obtained from two specifications with respect to goodness-of-fit proposed in the spirit of Vuong (1989) in both overlapping and nested models' cases. We found that a model with our proposed delinquency probability variable showed a statistically significant advantage compared to a benchmark model with delinquency dummy variables. We performed a default prediction power test based on the method proposed in Shumway (2001), and found a much stronger performance from the proposed model.

• Korean Journal of Acupuncture
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• v.22 no.2
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• pp.57-74
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• 2005

Objective : Frutus gardeniae, seed of Gardenia jasminoides Ellis is one of the crude drugs used for the treatment of inflammatory condition in oriental medicine. Methodes : The present study aimed to examine the analgesic effect and anti-inflammatory effect of Frutus gardeniae extract (FGE) on a rat model of ankle sprain pain, and the relations between FGE-induced effect and endogenous nitric oxide (NO) and inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and c-Fos protein expression in the spinal cord. As a chronic pain model, ankle sprain pain model was used to test the effect of FCE injection applied to acupuncture point. After the induction of ankle sprain, rats subsequently showed a reduced stepping force of the affected limb for at least the next 4 days. The reduced stepping force of the limb was presumably due to a painful knee. FGE dissolved in normal saline was injected several acupoints. Results : After the treatment, behavioral tests measuring stepping force were periodically conducted during the next 8 hours. FGE produced significant improvement of stepping force of the hindlimb affected by the ankle sprain lasting at least 4 hours. FGE produced the improvement of stepping force of the affected hindlimb in a dose-dependent manner. In addition, FGE injection showed inhibitory effect on the paw edema induced by ankle sprain. Both NO production and iNOS, COX-2 protein expression increased by ankle sprain were suppressed by FGE. FGE on combination with electroacupuncture (EA) produced more powerful and longer lasting improvement of stepping force of the hindlimb affected by the ankle sprain than either FGE or EA did. The present study suggest that FGE produces a potent analgesic effect on the ankle sprain pain model of the rat and that FGE-induced analgesia modulate endogenous NO through the suppression of iNOS/COX-2 protein expression.