• Annals of Clinical Neurophysiology
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• 제8권1호
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• pp.40-43
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• 2006

Background: Benign paroxysmal positional vertigo (BPPV) is a relatively common disorder, and is characterized by episodic vertigo and nystagmus which was provoked by head motion. However, little is known about the short and long-term outcome and the prognostic factors for recurrence of BPPV. In this pilot study, we tried to identify the prognostic factors of BPPV for short-term outcome. Methods: We analyzed clinical features of 32 patients (men=21, mean $age=60.4^{\circ}{\pm}12.6y$) with BPPV that was diagnosed by typical nystagmus induced by positioning maneuver. The induced nystagmus was recorded using video-oculography (VOG). According to the semicircular canal involved, BPPV patients were classified into horizontal, posterior, or anterior canal type. Univariate analysis for age, sex, and history of vertigo, and Kaplan-Meier analysis for each canal type were performed. Results: Horizontal (n=21, 65.6%) semicircular canal type BPPV was more common than the posterior one (n=11, 34.4%). Median follow-up period was 113 day (from 34 to 216 days). Four patients with horizontal canal type BPPV had recurrent attacks. Age, history of vertigo, and days prior to diagnosis were not different between canal type. Overall recurrence rate of horizontal canal type BPPV by Kaplan-Meier estimation was 19% at 60 days (p=0.13). Conclusions: Horizontal canal type BPPV was more common and recurred more frequently than posterior canal type in the present study. However, we did not find prognostic factors for recurrence of BPPV.

• Korean Journal of Ophthalmology
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• 제32권6호
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• pp.470-477
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• 2018

Purpose: To investigate the relationship between the progression of visual field (VF) loss and changes in lamina cribrosa depth (LCD) as determined by spectral-domain optical coherence tomography (SD-OCT) enhanced depth imaging in patients with primary open angle glaucoma (POAG). Methods: Data from 60 POAG patients (mean follow-up, $3.5{\pm}0.7$ years) were included in this retrospective study. The LCD was measured in the optic disc image using SD-OCT enhanced depth imaging scanning at each visit. Change in the LCD was considered to either 'increase' or 'decrease' when the differences between baseline and the latest two consecutive follow-up visits were greater than the corresponding reproducibility coefficient value ($23.08{\mu}m$, as determined in a preliminary reproducibility study). All participants were divided into three groups: increased LCD (ILCD), decreased LCD (DLCD), and no LCD change (NLCD). The Early Manifest Glaucoma Trial criteria were used to define VF deterioration. Kaplan-Meier survival analysis and Cox's proportional hazard models were performed to explore the relationship between VF progression and LCD change. Results: Of the 60 eyes examined, 35.0% (21 eyes), 28.3% (17 eyes), and 36.7% (22 eyes) were classified as the ILCD, DLCD, and NLCD groups, respectively. Kaplan-Meier survival analysis showed a greater cumulative probability of VF progression in the ILCD group than in the NLCD (p < 0.001) or DLCD groups (p = 0.018). Increased LCD was identified as the only risk factor for VF progression in the Cox proportional hazard models (hazard ratio, 1.008; 95% confidence interval, 1.000 to 1.015; p = 0.047). Conclusions: Increased LCD was associated with a greater possibility of VF progression. The quantitative measurement of LCD changes, determined by SD-OCT, is a potential biomarker for the prediction of VF deterioration in patients with POAG.

• 한국간담췌외과학회지
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• 제27권3호
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• pp.251-257
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• 2023

Backgrounds/Aims: This is a retrospective analysis of whether the 8th edition American Joint Committee on Cancer (AJCC) was a significant improvement over the 7th AJCC distal extrahepatic cholangiocarcinoma classification. Methods: In total, 111 patients who underwent curative resection of mid-distal bile duct cancer from 2002 to 2019 were included. Cases were re-classified into 7th and 8th AJCC as well as clinicopathological univariate and multivariate, and Kaplan-Meier survival curve and log rank were calculated using R software. Results: In patient characteristics, pancreaticoduodenectomy/pylorus preserving pancreaticoduodenectomy had better survival than segmental resection. Only lymphovascular invasion was found to be significant (hazard ratio 2.01, p = 0.039) among all clinicopathological variables. The 8th edition AJCC Kaplan Meier survival curve showed an inability to properly segregate stage I and IIA, while there was a large difference in survival probability between IIA and IIB. Conclusions: The 8th distal AJCC classification did resolve the anatomical issue with the T stage, as T1 and T3 showed improvement over the 7th AJCC, and the N stage division of the N1 and N2 category was found to be justified, with poorer survival in N2 than N1. Meanwhile, in TMN staging, the 8th AJCC was able differentiate between early stage (I and IIA) and late stage (IIB and III) to better explain the patient prognosis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3923-3926
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• 2015

Background: Lung cancer is a fatal malignancy with high mortality and short survival time. The aim of this study was to estimate survival rates of Iranian patients with lung cancer and its associate predictive factors. Materials and Methods: The study was conducted on 355 patients admitted to hospitals of West Azerbaijan in the year 2007. The patients were followed up by phone calls until the end of June 2014. The survival rate was estimated using the Kaplan-Meier method and log-rank test for comparison. The Cox's proportional hazard model was used to investigate the effect of various variables on patient survival time, including age, sex, Eastern Cooperative Oncology Group (ECOG) performance, smoking status, tumor type, tumor stage, treatment, metastasis, and blood hemoglobin concentration. Results: Of the 355 patients under study, 240 died and 115 were censored. The mean and median survival time of patients was 13 and 4.8 months, respectively. According to the results of Kaplan-Meier method, 1, 2, and 3 years survival rates were 39%, 18%, and 0.07%, respectively. Based on Cox regression analysis, the risk of death was associated with ECOG group V (1.83, 95% CI: 1 Conclusions: The survival time of the patients with lung cancer is very short. While early diagnosis may improve the life expectancy effective treatment is not available.

• Advances in pediatric surgery
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• 제12권2호
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• pp.202-212
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• 2006

The prognostic factors for extrahepatic biliary atresia (EHBA) after Kasai portoenterostomy include the patient's age at portoenterostomy (age), size of bile duct in theporta hepatis (size), clearance of jaundice after operation (clearance) and the surgeon's experience. The aim of this study is to examine the most significant prognostic factor of EHBA after Kasai portoenterostomy. This retrospective study was done in 51 cases of EHBA that received Kasai portoenterostomy by one pediatric surgeon. For the statistical analysis, Kaplan-Meier method, Logrank test and Cox regression test were used. A p value of less than 0.05 was considered to be significant. Fifteen patients were regarded as dead in this study, including nine cases of liver transplantation. There was no significant difference of survival to age. The age is also not a significant risk factor for survival in this study (Cox Regression test; p = 0.63). There was no significant difference in survival in relation to the size of bile duct. However, bile duct size was a significant risk factor for survival (Cox Regression test; p = 0.002). There was a significant difference in relation to survival and clearance (Kaplan-Meier method; p = 0.02). The clearing was also a significant risk factor for survival (Cox Regression test; p = 0.001). The clearance of jaundice is the most significant prognostic factor of EHBA after Kasai portoenterostomy.

• 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 Data and Information Science Society
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• 제23권4호
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• pp.739-748
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• 2012

최소제곱 서포트벡터기계 (least squares support vector machine)는 분류 및 비선형 회귀분석에서 유용하게 사용되고 있는 통계적 기법이다. 본 논문에서는 각 집단별로 생존자료가 관측된 경우 적용할 수 있는 LS-SVM을 제안한다. 제안된 모형은 임의우측 중도절단자료를 비선형 회귀모형에 적용할 수 있게 Kaplan- Meier의 중도절단분포의 추정값을 이용하여 구해진 가중값을 사용하고, 집단 간의 변동을 나타내기 위하여 임의효과항을 포함한다. 벌칙상수와 커널모수의 최적값을 구하기 위하여 일반화 교차타당성함수가 사용되고 모의실험에서는 임의효과항을 포함하지 않은 LS-SVM과 성능을 비교함으로써 제안된 방법의 우수성을 보이기로 한다.

• 대한소아치과학회지
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• 제48권1호
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• pp.12-20
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• 2021

이 연구의 목적은 소아 환자의 유구치 인접면 우식증 치료에 유동성 복합레진을 이용한 II급 와동 수복물의 생존율을 기성금속관과 비교하여 후향적으로 평가하는 것이다. 2015년 6월부터 2019년 8월까지 인접면 우식증으로 진단되어 유동성 복합레진과 기성금속관 수복 치료를 시행한 590명의 1,504개의 유구치에 대한 전자의무기록과 방사선사진을 조사하였다. 수집된 자료는 Kaplan-Meier method를 이용해 생존 분석을 하였다. 유동성 복합레진 수복된 치아의 1년 생존율은 98.5%, 3년 생존율은 87.7%, 평균 생존기간은 39개월이었으며, 기성금속관과 비교할 때 통계적으로 유의한 차이는 없었다(p = 0.896). 현 연구의 한계 내에서 유동성 복합레진을 이용한 II급 수복은 유구치 인접면 우식증 치료의 예지력 있는 선택지가 될 수 있다고 사료된다.

• 한국콘텐츠학회논문지
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• 제22권6호
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• pp.692-700
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• 2022

외국인 투자기업의 사멸 연구를 위해 2013년부터 2017년까지 국내 시장 외국인 투자기업을 연구의 대상으로 선정했다. NICE 평가정보(주) 외국인 투자법인 자료를 표본으로 수집하고, 정제를 거쳐 분석에 사용했다. 종속변수인 외국인 투자기업 사멸에 대한 실증비교 검증은 기업 특성 지표인 외국인 투자 지분율과 근로자 수, 재무 유동성 지표는 자본, 자산, 부채, 매출, 수익성 지표로는 영업이익과 매출이익을 분석에 재무비율 지표로 ROA와 ROE를 사용했다. 이후 외국인 투자기업의 소유 지분을 100% 소유한 단독 투자기업과 합작회사, 기업분류에 따른 대기업과 중소기업의 사멸률을 실증했다. 외국인 투자기업 사멸률 영향요인 분석에서는 기업의 종업원 수, 부채, 영업이익과 매출이익 모두 기업의 경영위험도를 낮춰 지속 가능한 경영을 유지하는 효과가 있은 것으로 조사되었다. 그러나 지분 투자율, 자본, 자산, 매출 지표는 유의하지 않은 것으로 조사되었다. 외국인 투자기업 사멸률 실증 비교분석 결과에서도 100% 지분을 소유한 단독 투자기업과 대기업이 합작기업과 중소기업보다 상대적으로 사멸의 위험이 낮고, 지속 가능한 경영 가능성이 큰 것으로 분석되었다.

• Journal of Chest Surgery
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• 제42권1호
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• pp.34-40
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• 2009

배경: 1960년대 이래로 복부 대동맥류의 주된 수술적 접근 방법은 경복막 접근법이나, 최근에는 후복막 접근법을 이용한 향상된 수술 성적들이 보고되고 있다. 하지만 후복막 접근법과 경복막 접근법의 비교에 대한 국내 연구는 제한적이다. 대상 및 방법: 2001년 1월부터 2007년 7월까지 복부대동맥류로 진단 받고 수술적 대동맥 치환술을 받은 36명 중 후복막 접근법을 이용한 17명과 경복막 접근법을 이용한 19명의 수술 전 위험인자, 술 후 합병증, 수술 사망률을 비교 분석하였다. 전체 36명의 환자에서 수술사망의 위험인자를 조사하고 Kaplan-Meier 생존 분석을 이용한 술 후 장기 생존율 조사하였다. 결과: 대상 환자 중 두 군간에 성별, 연령, 동반 질환의 유무, 흡연력, 파열 유무, 술 전 증상간의 유의한 차이는 없었으며, 대동맥 재건술식, 수술시간 및 술 후 합병증의 발생빈도에서도 유의한 차이가 없었다. 그러나 후복막 접근법 군에서 술 후 금식 기간 및 비위관 제거 기간이 짧았으며(p<0.05), 중환자실 재실 기간에서도 경복막 접근법 군에 비하여 유의하게 짧았다(p<0.05), 수술 사망은 총 6명(16.7%)이었으며 그 중 5명이 술 전 파열된 경우로, 단변량 분석에서 수술 전 1.8 mg/dL 이상의 혈중 크레아티닌 수치를 보이는 경우(p=0.016)및 파열된 복부 대동맥류(p<0.001)가 유의한 수술 사망의 위험 인자로 조사되었다. Kaplan-Meier 생존율 조사에서는 두 군간의 장기생존율의 차이는 없었으며 전체 환자의 5년 생존율은 57.5%였다. 결론: 본 연구 결과 후복막 접근법이 경복막 접근법에 비하여 중환자실 재실 기간이 짧고 술 후 금식 기간 및 비위간 거치 기간이 짧은 장점이 있었다. 따라서 후복막 접근법에 대한 특별한 금기가 없다면 후복막 접근법을 일차적으로 고려하는 것이 좋을 것으로 사료된다.