• 한국수산과학회지
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• 제37권3호
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• pp.186-191
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• 2004

The effects of temperature on the growth of larvae of wrinkled swimming crab (Liocarcinus corrugatus) under controlled laboratory conditions of 15, 20 and $24^{\circ}C$ were investigated (33.5 psu: 12L: 12B). Each specimen was maintained individually, the instar size was determined from exuvia, and the survival and intermolt period of each instar were recorded. There were no significant differences (P>0.05) in the survival rates at 15, 20, and $24^{\circ}C.$ Comparison of survival over the first 27 days between the three temperature regimes showed significant differences (P<0.001). The intermolt period increased with the instar number, and was greatly extended at the lowest temperature. The molt increment varied little with temperature, and had a mean value of $21.35\%$ over the whole study. Temperature had little effect on survival and molt increment.

• Journal of Gastric Cancer
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• 제1권3호
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• pp.161-167
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• 2001

Purpose: Although gastric carcinomas occur throughout the world and the incidence is on the decrease, they remain the most common type of carcinoma in Korea. Significant advancements in the diagnostics and the surgical treatment of gastric carcinomas have been achieved during the last three decades. The present retrospective study was undertaken to investigate the chronological changes in the clinical features, including clinicopathological findings, operative treatment, and prognosis of gastric carcinomas. Materials and Methods: A total of 1973 patients with a primary gastric adenocarcinoma who had been treated surgically during the period from 1983 to 1998 at the Department of Surgery, Korea University College of Medicine, were divided into two groups to evaluate chronological changes: 1007 patients had been treated during the period from 1983 to 1992 (early period) and 966 patients during the period from 1993 to 1998 (late period). Chronological changes in age, sex, ratio of early gastric cancer (EGC), and resectability were analyzed in all 1973 cases. For the 1755 resected cases, we also studied the chronological changes in the clinicopathological and treatment factors between the early-period (n=894) and the late-period (n=867) groups. Results: There were significant differences between the two periods with regard to age and ratio of EGC: EGC was more frequent in the late period. Univariate analysis of resected cases showed that gross type, tumor size, depth of invasion, UICC stage, and histological type were statistically significant. The analysis of the treatment factors revealed that total gastrectomies and extended lymphadenectomies were more frequent during the late period. The number of lymph nodes dissected was $26.0\pm12.7$ in the early period and $33.4\pm14.1$ in the late period (p<0.01). The 5-year survival rate in all cases was $51.4\%$ in the early period and $55.9\%$ in the late period. The stage-related survival rates (UICC 4th Ed., 1987) in the early vs. the late periods were $92.9\%\;vs.\;95.5\%$ in stage IA, $82.1\%\;vs.\;91.1\%$ in stage IB, $76.5\%\;vs.\;73.1\%$ in stage II, $46.5\%\;vs.\;52.1\%$ in stage IIIA, $14.5\%\;vs.\;33.6\%$ in stage IIIB, and $2.8\%\;vs.\;8.8\%$ in stage IV. There was a statistically significant difference in survival between stage IIIB and IV. Conclusion: These results suggest that the differences in the clinicopathological findings are related primarily to the increased number of early gastric cancer cases in the late period and that the improved survival noted during the late period for in stage IIIB and IV cancers might be related to extended surgery.

• 응용통계연구
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• 제19권3호
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• pp.395-406
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• 2006

임상시험 연구나 역학 연구에서 환자들의 예후는 흔히 생존을 추정을 통해 수량화 되곤 한다. 하지만 코호트 분석이나 완전분석에 의한 생존율 추정량들은 수년 전에 진단된 환자에 크게 의존하기 때문에 실제 생존율보다 더 낮게 추정하곤 한다. 본 연구에서는 최근의 생존정보를 잘 반영하는 생존을 추정을 위해 기간분석 방법을 통한누적한계 추정량을 제안하였고, 그 방법을 1993년 1월-1997년 12월 사이에 조사된 서울시 암등록 자료(Ahn등, 2002)에 적용하여 결과를 고찰하였다.

• 한국양식학회지
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• 제17권1호
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• pp.58-61
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• 2004

이 연구에서는 경남 통영에서 채집된 남방도화새우, Pandalus gracilis 유생의 적정 사육 온도와 수온이 성장에 미치는 영향을 파악하기 위해 10와 2$0^{\circ}C$(32.5∼34.5$\textperthousand$; 12L: 12D)두 온도 구간을 설정하여 이루어졌다. 유생의 생존율은 2$0^{\circ}C$가 1$0^{\circ}C$에 비해 높게 나타났으며, 유생의 탈피주기는 1$0^{\circ}C$에서 보다 긴것으로 나타났다.

• 대한수의학회지
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• 제39권4호
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• pp.838-845
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• 1999

To determine the prognostic factors for survival of dogs infected with canine parvovirus, clinical and laboratory data of 35 dogs with clinical signs compatible with canine parvoviral enteritis admitted to the Veterinary Medical Teaching Hospital, Seoul National University during the period 1997-1998 were collected. Dogs were grouped by some major covariates, which can be considered as guides to the relative prognosis of dogs in the different subgroups. The Kaplan-Meier survival analysis and Weibull proportional hazard model were used to estimate overall survival, evaluate the comparability between groups, and identify potential prognostic factors. The overall survival rate for all dogs was 45.7% over the study period, and the Kaplan-Meier estimate of one week survival was 0.4989. Gender was the most favorable prognosis ; male dog (median, 6 days) had significantly higher risk of dying than female dog (median, 17 days ; p = 0.0023). In addition to gender, age was significantly associated with survival, with juvenile dogs less than 6-month-old having higher risk (p = 0.0359). Dogs that vaccinated with complete protocol (p = 0.0374) and those of having higher value of mean corpuscular volume (p = 0.0346) were found to be of prognostic importance. The 7 dogs in which white blood cell count of less than 2000 had shorter median survival time (3 days) than the remaining 28 dogs (8 days), but no statistical significance was found between leukopenic and survival. The distribution of packed cell volume and hemoglobin measurement was such that the overall risk of dying in the two groups was comparable. Further studies are needed to more accurately assess these results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권2호
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• pp.68-75
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• 2014

Objectives: This study was performed to analyze the cumulative survival rate of Osstem implants (Osstem Implant Co., Ltd.) over a seven-year period. Materials and Methods: A total of 105 patients who had 467 Osstem implants that were placed at the Section of Dentistry, Seoul National University Bundang Hospital (Seongnam, Korea) from June 2003 through December 2005 were analyzed. The life table method and a cross-tubulation analysis, log rank test were used to evaluate the survival curve and the influence that the prognostic factors. The prognostic factors, i.e., age and gender of patients, diameter and length, type of implants, bone graft history and loading time were determined with a Cox proportional hazard model based on logistic regression analysis. Results: The seven-year cumulative survival rate of Osstem implants was 95.37%. The Cox proportional hazard model revealed that the following factors had a significant influence on survival rate; increased diameter, reduced prosthetic loading period and performance of bone grafting. Conclusion: The osstem implants showed satisfactory results over the seven-year study period.

• Journal of Chest Surgery
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• 제30권12호
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• pp.1214-1218
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• 1997

폐전이 골 연부조직 육종에 대한 폐절제 및 합병치료의 성적을 분석하였다. 1986년부터 1996년까지 14례 (남자 11례, 여자 3례)에서 15회의 폐절제술을 시행하였는데, 1례에서는 폐전이 육종의 재발로 2회의 폐절제술을 시행하였다. 절제된 폐전이 육종의 수는 1∼5개였다. 폐전이 육종의 병리조직학적 소견상 4례는 골육종 이었으며, 10례는 연부조직 육종이었다 폐절제술후 평균 생존기간은 29.2개월이었으며, Kaplan-Meier식에 의 한 5년생존율은 33.2%였다. 14례중 3례의 종양 자유기간이 3년이상으로 평균 생존기간은 52.6개월이었으며, 3년 이하의 11례는 추적기간중 모두 사망하여 이들의 평균 생존기간은 17.3개월이었다. 결론적으로 폐전이 육종에 대한 폐절제술은 뚜렷한 수명 연장 효과가 있을 것으로 생각된다.

• Journal of Periodontal and Implant Science
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• 제37권4호
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• pp.671-679
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• 2007

Background: $TiUnite^{TM}$ is a highly crystalline and phosphate enriched titanium oxide surface which has a unique porous surface structure. This improved implant surface enhances bone response and reduces healing period. It also assures early stability of implant. These help to increase the success of implant. The aim of this study is to evaluate the survival rate of $TiUnite^{TM}$ surfaced single implant. Materials and methods: A retrospective analysis of 89 $TiUnite^{TM}$ surfaced implants replacing a single tooth was assessed according to their dental record. The age of the patients ranged from 17 to 82 years (mean age: $45.8{\pm}14.6)$. Data were recorded regarding the survival rate of these implants. Results: Fifty-two implants (57%) were placed in the maxilla, and 37 (43%) in the mandible. Over 75% were placed in the posterior area. Of the placed implants, 67% were the wide type. while 25% were the regular type and only 8% were of the narrow type. The single implants produced an overall clinical survival rate of 96.6% over the observation period (mean 17.9 months). Among 89 implants, only 2 implants were removed and one implant was submerged. Conclusion: According to these data, $TiUnite^{TM}$ surfaced implant in a single tooth restoration showed favorable survival rate although this study was done in a short term period.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제25권2호
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• pp.132-142
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• 2023

Objective: Dual antiplatelet therapy (DAPT) is usually temporarily used after stent-assisted coil embolization (SACE), and is commonly converted to mono antiplatelet therapy (MAPT) for indefinitely. In this study, we aimed to find the possibility of discontinuing MAPT, and to determine the proper period of DAPT use. Methods: We used the Standard Sample Cohort DB dataset from the National Health Insurance Sharing Service. Among approximately 1 million people in the dataset, SACE was performed in 214 patients whose data this study analyzed. The relationship between discontinuation of antiplatelet therapy and intracranial hemorrhage or cerebral infarction was analyzed using multiple logistic regression, considering all confounding variables. The survival rate according to the continuation of antiplatelet therapy was obtained using Kaplan-Meier analysis, and the difference in survival rate according to the continuation of antiplatelet therapy was verified using the log-rank test. The hazard ratio according to continuation of antiplatelet therapy was obtained using the Cox proportional hazards model. The analysis was conducted by applying the same statistical method to the duration of DAPT use. Results: Among 214 patients who underwent SACE, 50, 159 and five patients continued, discontinued and did not use antiplatelet therapy (except at the time of procedure), respectively. In multiple logistic regression analysis, discontinuation of antiplatelet agents (including aspirin) and the period of DAPT use did not affect the occurrence of intracranial hemorrhage or cerebral infarction, considering various confounding factors. In the survival analysis according to the continuation of antiplatelet agents, patients who continued to use antiplatelet agents had a higher survival rate than those in other groups (p=0.00). The survival rate was higher in the rest of the group than in the group that received DAPT for three months (p=0.00). Conclusions: Continuation of antiplatelet agents or the period of DAPT use did not affect the occurrence of intracranial hemorrhage or cerebral infarction. Considering the survival rate, it would be better to maintain at least three months of antiplatelet therapy and it might be recommended to continue DAPT use for 12 months.

• Osong Public Health and Research Perspectives
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• 제5권4호
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• pp.187-192
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• 2014

Objectives: Measurement of the incidence of the human immunodeficiency virus (HIV) is very important for epidemiological studies. Here, we determined the recency period with the AxSYM avidity assay and the BED-capture enzyme immunoassay (BED-CEIA) in Korean seroconverters. Methods: Two hundred longitudinal specimens from 81 seroconverters with incident HIV infections that had been collected at the Korea National Institute of Health were subjected to the AxSYM avidity assay (cutoff = 0.8) and BED-CEIA (cutoff = 0.8). The statistical method used to estimate the recency period in recent HIV infections was nonparametric survival analyses. Sensitivity and specificity were calculated for 10-day increments from 120 days to 230 days to determine the recency period. Results: The mean recency period of the avidity assay and BED-CEIA using a survival method was 158 days [95% confidence interval (CI), 135-181 days] and 189 days (95% CI, 170-208 days), respectively. Based on the use of sensitivity and specificity, the mean recency period for the avidity assay and BED-CEIA was 150 days and 200 days, respectively. Conclusion: We determined the recency period to estimate HIV incidence in Korea. These data showed that the nonparametric survival analysis often led to shorter recency periods than analysis of sensitivity and specificity as a new method. These findings suggest that more data from seroconverters and other methodologies are needed to determine the recency period for estimating HIV incidence.