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연구논문 : 수술 전 알파태아단백치가 높은 간세포암 환자에서 간절제술 후 알파태아단백만을 이용한 추적관찰이 가능한가?
신우영 ( Woo Young Shin ),서경석 ( Kyung Suk Suh ),김태훈 ( Taehoon Kim ),전영민 ( Young Min Jeon ),이남준 ( Nam Joon Yi ),이건욱 ( Kuhn Uk Lee ) 대한간학회 2010 Clinical and Molecular Hepatology(대한간학회지) Vol.16 No.2
Background/Aims: The follow-up strategy after hepatectomy for hepatocellular carcinoma (HCC) usually depends on the experience of physician, resulting in frequent imaging studies, which leads to increased cost. Hence, we investigated the role of monitoring alpha-fetoprotein (AFP) levels after hepatectomy in patients with preoperative high AFP. Methods: From January 2000 to December 2004, 66 patients who underwent curative hepatectomy due to HCC with preoperative AFP level >400 ng/ml were reviewed. Changes in AFP level after the operation were investigated. The recurrence was suspected in case of two consecutive increase of AFP over cut-off value. Cut-off value was determined by ROC curve. All patients were divided into 2 groups: patients who met the definition (Group S) and those who didn`t (Group D). Results: AFP level of 20ng/ml was proposed as the cut-off value for diagnosis of recurrence by ROC curve. Thirty two patients who didn`t have the AFP level decreased below 20 ng/ml after the resection had HCC recurred, whereas 16 out of 34 patients who had AFP decreased had tumor recurrence. The AFP level of patients without recurrence was kept below 20 ng/ml during the follow-up. The AFP level of 44 out of 48 recurred patients increased over 20ng/ml upon recurrence. By definition, group D were 5 patients. In 4 patients of group D, the AFP level didn`t increase above 20 ng/ml upon recurrence. These patients had HCC and they recurred 1 year after the surgery. Conclusions: In patients with preoperative AFP level >400 ng/ml, the AFP level tended to increase above 20ng/ml at recurrence mostly within 1 year. Hence, we proposed that these patients could be monitored by only AFP until 1 year after surgery.
이분산성 존재시 효율적 정보기반기준 분위수 회귀모형 선택법
신우영(Wooyoung Shin),정윤서(Yoonsuh Jung) 한국데이터정보과학회 2021 한국데이터정보과학회지 Vol.32 No.5
이 논문은 오차의 이분산성 존재시 분위수 회귀모형의 선택에 대한 다양한 방법들을 제안한다. 분위수 손실함수 (check loss function)는 분위수 회귀분석에서 모형의 적합 과정과 선택 과정에 모두 사용된다. 저자들의 관심은 분위수 회귀모형의 선택에 (또는 조율 모수의 선택에) 있기 때문에, 모형의 적합에는 항상 분위수 손실함수를 사용한다. 모형의 선택 방법 중에는 정보기반기준(information-based criteria)이 많이 사용되며, 기존의 정보기반기준들은 오차의 이분산성 존재를 고려하지 않기 때문에 효율적인 모형 선택에 제약이 있다. 이를 해결하고자 본 논문에서는 분위수 손실함수를 이용한 모형의 선택시 관측값에 서로 다른 가중치를 부여하여, 관측값에 따른 변동성을 고려하는 새로운 방법론을 제안한다. 서로 다른 가중치를 추정하기 위하여 반응변수의 사분위수 범위를 추정하고, 이를 이용해 관측값에 따라 달라지는 반응변수의 변동을 모형 선택 과정에 반영한다. 그 결과 변동성이 큰 부분의 상대적인 중요도가 낮아져서, 변수 선택이나 조율 모수의 선택에 미치는 영향이 줄어든다. 선형모형과 비선형 모형인 경우로 나누어 제안하는 방법론의 구체적 적용 방법을 제시하고, 각각의 제안하는 방법론의 효율성을 모의 실험과 실제 데이터 분석을 통하여 제시한다. We propose a class of methods for the tuning parameter selection in quantile regression model when the errors are heteroscedastic. Check loss function is commonly used for quantile regression in model fitting and model (or tuning parameter) selection. As we are interested in the tuning parameter selection, we always use check loss function for the model fitting process. Information-based criteria are widely used for model selection, but it does not consider heteroscedastic errors. To attack this issue, we suggest using different weights in the information-based criteria. Specifically, we estimate the variation in the response variable using interquartile range (IQR). IQR is then utilized to yield weight for each sample. The effect of the samples in the high variation is expected to reduce due to the proposed method. The form of the proposed method changes depending on whether the model is linear or nonlinear. Its effectiveness for treating the heteroscedasticity is presented via simulated data and two real data sets.
Cytodex 3 미립담체를 이용한 간세포의 구상체 배양에서 간세포와 미립담체 간의 최적 비율
신우영(Woo Young Shin),이건욱(Kuhn Uk Lee),이해원(Hae Won Lee),조응호(Eung-Ho Cho),이남준(Nam-Joon Yi),서경석(Kyung-Suk Suh) 대한외과학회 2007 Annals of Surgical Treatment and Research(ASRT) Vol.73 No.3
Purpose: The mass cultivation of functional hepatocytes is a key factor of a bioartificial liver. Combining spheroid and microcarrier cultures has been applied for enhancing the cell viability and metabolic activities. Hence, the optimal number of hepatocytes per microcarrier was investigated. Methods: Firstly, spheroid cultures were carried out with 1 g Cytodex 3 microcarrier plus 2×10?, 4×10? and ?×10? viable hepatocytes per flask. The numbers of hepatocytes per microcarrier were approximately 666.7, 133.3 and 26.7, respectively. The control group consisted of a spheroid culture of 4×10? hepatocytes without any microcarrier. According to the primary experimental results, spheroid cultures with 1×10? of hepatocytes plus 1 g, 2 g and 3 g of the Cytodex 3 microcarrier were performed. The numbers of hepatocytes per microcarrier were approximately 33.3, 16.7 and 11.1, respectively. The control group consisted of a spheroid culture of 1×10? hepatocytes. The cell viabilities were assayed using a Cell Counting Kit-8; with the albumin production assayed using ELISA. Results: According to the primary experiment, the group consisting of 26.7 hepatocytes per microcarrier showed the highest viability (P<0.01). However, there was no statistical difference in the albumin production between the groups (P=0.744). The second Experiment showed the groups consisting of 11.1 and 16.7 hepatocytes per microcarrier had higher viabilities than the other hepatocyte and control groups (P<0.01). The albumin production was similar for each group (P=0.187). Conclusion: With respect to their application to a bioartificial liver, about 130 hepatocytes per microcarrier was appeared to be good for the mass cultivation of a hepatocytes spheroid culture using the Cytodex 3 microcarrier.
신우영(Woo-young Shin),송정수(Jung Soo Song),김정하(Jung-ha Kim) 대한임상노인의학회 2021 대한임상노인의학회지 Vol.22 No.2
Polypharmacy is a major public health concern globally with aging populations and the increase in the prevalence of multimorbidity. This review provides an overview of polypharmacy and its management programs in older patients and describes the development direction and challenges of polypharmacy management strategies while considering the current situation in Korea. Although polypharmacy is often regarded as the routine use of at least five medications, the definition is more useful in terms of clinical appropriateness rather than the number of medications administered. The goal of polypharmacy management should be to ensure rational prescription based on clinical evidence and appropriate medication use in consideration of the patient’s individual factors. In order for doctors, nurses, and pharmacists to collaborate within a multidisciplinary team to ensure a comprehensive medication review, it would be effective to implement a management model in the form of a systematic program within the healthcare delivery system. Some countries are introducing sustainable polypharmacy management programs and developing standardized polypharmacy guidelines. It is required to conduct further benchmark studies of polypharmacy management programs in other countries that have proven their effectiveness while considering the Korean situation.