• Journal of the Korean Data and Information Science Society
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• 제25권4호
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• pp.921-929
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• 2014

A bivariate exponential distribution with a location parameter is proposed as a model for a two-component shared load system with a guarantee time. Some statistical properties of the proposed model are investigated. The maximum likelihood estimators and uniformly minimum variance unbiased estimators of the parameters, mean time to failure, and the reliability function of system are obtained with unknown guarantee time. Simulation studies are given to illustrate the results.

• Tuberculosis and Respiratory Diseases
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• 제40권6호
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• pp.669-676
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• 1993

연구배경 : 종양세포는 세포의 분열성장이 매우 왕성하므로 정상 세포에 비하여 세포분열 주기 중 S-Phase fraction(SPF)의 증가를 예상할 수 있다. 같은 종양증에서도 SPF가 높으면 종양의 성장이 훨씬 빠를 것으로 생각되며, 이러한 종양세포의 생물학적 특성을 이용하여 원발성 편평상피성 폐암 환자에서 SPF와 생존기간과의 관계를 연구하였다. 방법 : 1985년 9월 부터 1990년 3월 까지 원광의대 부속병원에서 원발성 편평상피성 폐암으로 진단받고나서, 수술, 방사선, 화학요법 등을 실시받지 않고 사망한 21례를 대상으로 하였다. SPF 분석방법은 paraffin에 보관된 병리조직을 처리하여 유식세포 분석법에 의한 DNA histogram으로서 분석하였다. 결과 : 1) 전 대상군의 평균 생존기간은 225(${\pm}162$)일 이었고, TNM 병기, PS scale이 진행할 수록 단축되는 양상이다. 2) 전 대상군의 평균 SPF는 23.4(${\pm}11.3$)% 이었으며, TNM 병기, PS scale 별로 구분하여 비교한 결과, TNM 병기, PS scale의 진행정도와 SPF는 관계가 없었다. 3) SPF 20%를 기준으로 한, high SPF 군과 low SPF 군의 평균 생존기간은 각각 153(${\pm}99$)일, 342(${\pm}180$)일 로서 유의한 차이가 있었다(p<0.01). high SPF군과 low SPF군을 TNM 병기, PS scale 별로 구분하여 비교하여도 역시 유의하게 high SPF군이 low SPF 군 보다 평균 생존기간이 짧았다. 결론 : 편평상피성 폐암 환자에서 종양세포의 SPF가 증가되어 있으면, 예후가 유의하게 좋지 않으며, SPF는 TNM 병기, PS scale과는 무관한 독립된 예후추정 인자로서의 임상적 이용이 가능하다고 생각된다.

• 대한약침학회지
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• 제13권1호
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• pp.5-14
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• 2010

Objectives : This study was performed to examine the anticancer effect of mountain ginseng Pharmacopuncture(MGP) to the nude mouse of lung carcinoma induced by NCI-H460 human nonsmall lung cancer cells. Methods : Human lung cancer (NCI-H460) cells were cultured and applied to evaluate anti-tumor activity in nude mice. After confirmed tumor growth in mice, MGP was treated per 0.1ml/kg dose to intraperitoneal and intravenous injection everyday for four weeks. And checked the changes in body weights, tumor volume, mean survival time and percent, increase in life span, histo-pathological findings, organ weights, and blood chemistry levels. Results : The results of in vivo study showed that MGP may have potential as growth inhibitor of solid tumor induced NCI-H460 without marked side effects. MGP inhibited dosage-dependently the growth of NCI-H460 cell-transplanted solid tumor compared with the control group. And mean survival time of MGP treated group was prolonged comparing with control group. Generally the group of intravenous injection is more effective than intraperitoneal injection. Conclusion : These results were suggested that MGP may be a useful anticancer agent for therapy of human lung cancer. And follow study need for the certain evidence.

• 한국임상수의학회지
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• 제20권2호
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• pp.159-165
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• 2003

This study was performed to determine the effect of green tea on the late biological effect (survival, hematological change, carcinogenesis) of mice irradiated with 3 Gy of gamma-radiation. There was little difference in body weights between normal and irradiated mice. Survival rate were decreased in irradiated mice and the survival rate and mean survival time of the groups treated with green tea were far better than the irradiation control group. An elevation of mean number of total leukocyte or lymphocyte counts was seen at week 12 of the group treated with green tea. Stimulated recovery by the extract from green tea was also observed in thrombocyte. Main gross findings of irradiated mice were appeared as enlargement of spleen, thymus and liver, tumorous nodules in lung and cyst or mass in ovary. Microscopically, there were various findings including hematopoietic and lymphoid tumor, lung cancer, ovarian cancer and cancer of other lesions. Green tea reduced the incidence of tumor development. Further studies are needed to characterize better the protective nature of active compounds.

• Journal of Preventive Medicine and Public Health
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• 제23권1호
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• pp.77-86
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• 1990

Between 1977 and 1987, 20 patients with mesothelioma were treated at Severance Hospital. Data was gathered from medical charts at the time of hospitalization of mesothelioma patients and from a follow-up questionnaire by mail or telephone. The results acquired were as follows : 1. Among the 20 patients, 11 men and 9 women with mesothelioma were identified. The mean age at hospitalization was 47 years and 11 mesothelioma patients were known or presumed to be dead during the different observation periods. 2. Only one mesothelioma patient had a definite history of occupational asbestos exposure. 3. The sites of origin of mesothelioma were the pleura(13), peritoneum(2), pericardium(2), mediastinum (2), and pelvis(1). Common symptoms included dyspnea, chest pain, abdominal distension, etc. 4. Pathologically, mesotheliomas were divided into 14 malignant types and 6 benign types ; and histologically, 8 fibrous mesotheliomas and 3 epithelial mesotheliomas were shown. 5. There was a statistically significant difference in survival rate according to pathologic type and smoking status. In the groups with malignant mesothelioma, 50% survival time from first symptoms was 18 months and that from diagnosis was 11 months. Also, 75% survival time from diagnosis was 6 months in the smoking groups and 19 months in the non-smoking groups.

• Annals of dermatology
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• 제30권6호
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• pp.668-675
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• 2018

Background: Drug survival, defined as the time until discontinuation, is a parameter reflecting real-world therapeutic effectiveness. Few studies have examined the influence of economic factors on the drug survival of biologic agents for psoriasis, particularly in Asian countries. Objective: To determine the drug survival for ustekinumab in real-life settings and investigate the factors affecting drug survival for psoriasis patients in Korea. Methods: We evaluated 98 psoriasis patients who were treated with ustekinumab at a single center. We analyzed the efficacy and drug survival of ustekinumab. Cox proportional hazard analysis and competing risk regression analysis were performed to reveal the factors affecting the drug survival of ustekinumab. Results: The overall mean drug survival was 1,596 days (95% confidence interval [CI], 904~2,288). Among the 39 cessations of ustekinumab treatment, 9 (23.1%) patients discontinued treatment after experiencing satisfactory results. Multivariate Cox proportional hazard analysis revealed that paying on patients' own expense was the major predictor for the discontinuation of ustekinumab (hazard ratio [HR], 9.696; 95% CI, 4.088~22.998). Competing risk regression analysis modeling of discontinuation because of factors other than satisfaction of an event also revealed that ustekinumab treatment at the patient's expense (HR, 4.138; 95% CI, 1.684~10.168) was a predictor of discontinuation rather than satisfaction. Conclusion: The results of our study revealed that the cost of biologics treatment affects the drug survival of ustekinumab and suggested that economic factors affect the drug survival of ustekinumab treatment in Korea.

• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2006년도 추계학술대회
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• pp.327-336
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• 2006

The odds ratio is used for assessing the disease-exposure association, because epidemiological data for case-control of cohort studies are often summarized into 2 ${\times}$ 2 tables. In this paper we define the odds ratio function(ORF) that extends odds ratio used on discrete survival event data to continuous survival time data and propose estimation procedures with censored data. The first one is a nonparametric estimator based on the Nelson-Aalen estimator of comulative hazard function, and the others are obtained using the concept of empirical odds ratio. Asymptotic properties such as consistency and weak convergence results are also provided. The ORF provides a simple interpretation and is comparable to survival function or comulative hazard function in comparing two groups. The mean square errors are investigated via Monte Carlo simulation. The result are finally illustrated using the Melanoma data.

• 한국작물학회지
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• 제50권4호
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• pp.276-280
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• 2005

Low temperature is one of the most severe abiotic stress factors limiting growth, productivity and distribution of winter cereals. Reliable field screening method, which can detect small differences in winter survival, is important for the effective selection and development of plants to identity superior cold tolerant winter cereal genotypes. This study was undertaken to provide improved screening method of winter hardiness in the field by increasing the accuracy in evaluating winter hardiness of barley (Hordeum vulgare L.). We introduced furrow in field screening of winter survival. By sowing the plants at the ridge and base, we could minimize the effect of topographic variation in a field by giving higher and lower level of stress at the same time. This method could be used by breeders to conduct accurate evaluation of winter hardiness by selecting the better treatment, which shows close to normal distribution, among the winter survival rate from the ridge, base and mean survival rate of the two in a screening field.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3219-3221
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• 2013

Background: This study used receiver operating characteristic (ROC) curves to screen Surveillance, Epidemiology and End Results (SEER) skin melanoma data to identify and quantify the effects of socioeconomic factors on cause specific survival. Methods: 'SEER cause-specific death classification' used as the outcome variable. The area under the ROC curve was to select best pretreatment predictors for further multivariate analysis with socioeconomic factors. Race and other socioeconomic factors including rural-urban residence, county level % college graduate and county level family income were used as predictors. Univariate and multivariate analyses were performed to identify and quantify the independent socioeconomic predictors. Results: This study included 49,999 parients. The mean follow up time (SD) was 59.4 (17.1) months. SEER staging (ROC area of 0.08) was the most predictive foctor. Race, lower county family income, rural residence, and lower county education attainment were significant univariates, but rural residence was not significant under multivariate analysis. Living in poor neighborhoods was associated with a 2-4% disadvantage in actuarial cause specific survival. Conclusions: Racial and socioeconomic factors have a significant impact on the survival of melanoma patients. This generates the hypothesis that ensuring access to cancer care may eliminate these outcome disparities.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5043-5047
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• 2013

Background: This is a part of a larger effort to characterize the effects on socio-economic factors (SEFs) on cancer outcome. Surveillance, Epidemiology and End Result (SEER) bone and joint sarcoma (BJS) data were used to identify potential disparities in cause specific survival (CSS). Materials and Methods: This study analyzed SEFs in conjunction with biologic and treatment factors. Absolute BJS specific risks were calculated and the areas under the receiver operating characteristic (ROC) curve were computed for predictors. Actuarial survival analysis was performed with Kaplan-Meier method. Kolmogorov-Smirnov's 2-sample test was used to for comparing two survival curves. Cox proportional hazard model was used for multivariate analysis. Results: There were 13501 patients diagnosed BJS from 1973 to 2009. The mean follow up time (SD) was 75.6 (90.1) months. Staging was the highest predictive factor of outcome (ROC area of 0.68). SEER stage, histology, primary site and sex were highly significant pre-treatment predictors of CSS. Under multivariate analysis, patients living in low income neighborhoods and rural areas had a 2% and 5% disadvantage in cause specific survival respectively. Conclusions: This study has found 2-5% decrement of CSS of BJS due to SEFs. These data may be used to generate testable hypothesis for future clinical trials to eliminate BJS outcome disparities.